2.1.2: European Medieval Art (500 CE CE)
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Introduction
The Medieval, also known as the Middle Ages period in Europe, was bounded by the fall of the Roman Empire. It leads to the beginning of the Renaissance art period in Europe. At this time, Christianity was established as the primary religion bringing specific ideals and ecclesiastical standards. The fragments from the Roman Empire defined the boundaries of many European countries. The countries developed a political system based on the monarchy, a ruler empowered by heredity. Most people were farmers who lived in small rural villages. Women were primarily responsible for childcare, food preparation, tending livestock, and helping at harvest time to gather crops. Women who lived in the larger towns were responsible for childcare and food preparation. They also helped their father or husband in the many trades and crafts needed to support city life, including creating textiles, leather goods, or different metal objects or managing shops and inns.
In this period, the beliefs and teachings of the Catholic church generally informed people's lives. Biblical readings reflected in medieval art frequently portrayed Eve as responsible for leaving paradise, generating the long-held belief that women were weaker than men, easily tempted to sin, and inferior to men. Based on this story and other biblical tales, men's authority over women was emphasized, teaching women to be submissive. Biblical stories about the Virgin Mary became the elevated image of a woman as a powerful model of virtue and motherhood. All types of art forms were based on the ideas of Mary. The few places women could have power were to be a queen, regent to the throne, or the abbess of a convent.  A woman could marry or become a nun and live forever in a monastery to pray and work.
Visual arts, generally based on religious concepts, dominated artistic values. Unlike today's art, the concept of European medieval art was based on the ideas of theory and doctrine. It wasn't until later that artists became interested in their individuality. Medieval art was functional and an elevation of God and the church. The ruling class and the church commissioned most of the art seen in cathedrals, manuscripts, paintings, and sculptures. Very little identifiable art created by women is known today. Although men dominated art, the nuns lived in isolation and produced illuminated manuscripts that still survive today. Nuns were transformed when entering the convent, leaving their previous life and name behind and adopting a new name. In the convent, a woman was taught to read and write, and copying biblical passages was considered a privilege. Most illuminated manuscripts are anonymous because the nun's vows prevented her from using a name on her work. One exception was for the convent abbess or prioress as the leader and the permission to sign her name.
- Hildegard of Bingen (1098-1179)
- Herrad of Landsberg (c. 1130-1195)
- Ende (10 th century)
- Sibilla von Bondorf (c. 1440-1525)
- Claricia (or Clarica) (13 th century)
- Guda (Guta) (12 th century)
- Gunnborga (11 th century)
- Bayeux Tapestry (11 th century)
Hildegard of Bingen
Hildegard of Bingen (1098-1179) was born in Germany. Her family name was unknown, although early writers did note the family was wealthy. She suffered from poor health as a child, with trouble walking and seeing. Hildegard entered the convent and learned to read, write and sing religious psalms as part of her spiritual training. Even as a child, Hildegard believed she had visions of the future. When she related the visions to others, they did not believe her, and she learned to keep the concepts to herself. When Hildegard was almost forty years old, she was told by a superior to write about her visions. People began to believe the messages in Hildegard's writings and came from all parts of the country to hear her speak. Hildegard's works included medical information, visionary messages, and philosophical theories. She became a well-known composer of sacred music, and more of Hildegard's liturgical chants have survived than any other medieval composer. Hildegard wrote letters and poems, doing her extensive writings into illuminated manuscripts.
Scivias was the first of Hildegard's illuminated manuscripts she created about her religious visions. She divided the manuscript into three sections based on her concept of the Trinity. Part one included how she was instructed to compose the work and six different visions. The second part dealt with personal salvation through the church's teachings, and the third section described her visions about good and evil and the kingdom of God. Hildegard also included songs she thought of as the voice of heaven. It is unclear if she produced the illustrations or only made sketches of the visions and had others complete the images. At the beginning of each section, Hildegard opened with a prophetic statement. In the first section, she wrote, "I heard again the voice from heaven speaking to me"; in section two, "And again I heard a voice from the heavenly heights speaking to me," and in section three, "And I heard that light who sat on the throne speaking." [1]
The frontispiece of Scivias (3.2.1) is the image of Hildegard receiving the heavenly vision as she sketches the visions on the wax tablet. Volmar, one of her teachers, is watching her work. The visions are the focal point with a direct line down from above, into her head, down her arm, and onto the tablet. The Choir of Angels (3.2.2) is one of the illustrations of her twenty-six visions. The illumination is made with inks and gold leaf. The angels form concentric circles around God according to their defined hierarchy. The first sphere was the seraphim and cherubim, closest to God. As part of the first section, Hildegard wrote the music inspired by her visions. Her music was from the 12 th century and is still used in religious ceremonies. The video is a short selection of her music.
Herrad of Landsberg
Herrad of Landsberg (c. 1130-1195) was the Abbess of Hohenburg, a convent in eastern France. She was born into a noble family and entered the abbey when she was young. Many girls and women were from wealthy families and received a broader education than most young girls. As Herrad grew older, she rose within the abbey, eventually becoming the abbess. At first, she worked to rebuild the abbey and incorporate more of the surrounding land under the abbey's jurisdiction. As the abbess for twenty-eight years, she was well-liked both inside and outside the abbey and could maintain the support of the secular world.
About 1159, Herrad started her well-known work and was thought to be the first encyclopedia written by a woman, Hortus deliciarum (Garden of Delights) . The illuminated manuscript covered the known sciences and literature and was reported to teach the convent women about the biblical and moral ideals of the sciences. The manuscript was immense, with 648 pages on 324 parchment sheets. [2] The manuscript was written in Latin with notes in German. Over 300 illustrations decorated the text, representing historical, theological, and literary themes. The manuscript was based on knowledge existing in the 12 th century with poems and texts from classical writers.  The black background emphasizes the red tongues of fire, as devilish creatures tormented each person.  Philosophy and the Seven Liberal Arts (3.2.4) differ in looks and spirit. The light background is decorated with colorfully dressed people in the outer ring, each representing the seven liberal arts: Grammar, Logic, Rhetoric, Geometry, Arithmetic, Astronomy, and Music. The seven categories were defined in the late Roman period and used for medieval European education. Philosophy sits in the center as a queen with Socrates and Plato at her feet, the long scroll stating, "All wisdom comes from God. Only the wise can do what they will." [3]
Ende
Ende (10 th century) was the first known Spanish female to work on illuminated manuscripts and was believed to be a nun. Her work was identified by the signature " pintrix et D[e]I aiutrix (paintress and helper of god)." [4] Ende's work is seen in the illuminated manuscript Gerona Beatus. How much of the illustrated work was done by Ende is still debated; however, some historians believe most of the work was accomplished by her. The Gerona Beatus had two specific sections, Commentary on the Apocalypse , the manuscript written by Beatus of Liébana, and the Book of Daniel by Jerome. The illuminators were identified as Ende and the monk Emeterius.
The Last Judgment from the Gerona Beatus (3.2.5) demonstrates the concepts of the last judgment. The top half of the image shows the blessed rising towards the heavens while the sinful in the bottom half are descending into the horrors of hell. Those damned to hell are shackled as they fall while those going to heaven move towards the light. Maiestas Domini (3.2.6) features the image of Christ seated on a throne as he holds a gold disk in one hand and a closed gold book in his left hand. He is outlined by a sizeable quadrangular shape intersected with a rhombus. The evangelists, Mathew, Mark, Luke, and John, are represented, each facing the Christ image as they also hold a golden book. Each page is very detailed and uses color to define the spirit, feeling, and emotion.
Sibilla von Bondorf
Sibilla von Bondorf (c. 1440-1525) was a nun in a Clarissan convent in Germany. Much of von Bondorf's work was for prayer books or books used in the liturgy. Her primary work was a set of illustrations based on the lives of Saint Francis, Saint Clara, and Saint Elisabeth. Copies of her work were widely used among other convents. The full-page illustrations by von Bondorf included 52 for Saint Francis, 33 for Saint Clara, and 14 for Saint Elisabeth. Religious changes in Germany in the 1400s brought opportunities for women in convents to create and produce manuscripts and liturgical books. Although von Bondorf was not a trained artist, she mastered using line, color, and design. She developed perspective in her work by using patterns to delineate and unify the image's foreground and background. In one of the pages from the images of Saint Francis (3.2.7), von Bondorf uses bright colors and gold. The rug is highly patterned and anchors the bottom of the image. Saint Francis is standing on a chair, preaching to those who are opening their minds to his word. Von Bondorf used patterns extensively on the red-leaved background, the wood-grain door, and the elegant halos.
Claricia
Claricia (or Clarica) was a German artist who illuminated manuscripts in the late 12th or early 13 th century and was probably a nun in a Bavarian convent. Her most famous work was a German psalter (3.2.8) (a manuscript of the Psalms). The psalter was made on parchment with a large, elaborate letter Q. The tail of the Q is a self-portrait of Claricia swinging from the bottom of the letter with her name inscribed by her head. Scholars disagree on whether she was a nun or a high-born lady. One scholar believed her clothing, uncovered head, and braids indicate she was probably a lay student attending classes at the convent and working on manuscripts.
Guda
Guda (Guta) was born in Germany in the 12 th century as a nun and illuminator. Guda was one of the first women to develop a self-portrait in a manuscript, opening the door for those women following her. Guda created her image set in an initial letter (3.2.9) for the manuscript based on the homilies of St. Bartholomew. She drew herself dressed as a nun and wrote, "Guda, a sinner, wrote and painted this book." [5] She described herself as a sinner and an artist and hoped to be saved. By creating the illustrated initial, Guda made a signature and identified herself as a scribe.
Gunnborga
Gunnborga (11 th century) was from Sweden and was a runemaster. A runestone (3.2.10) was inscribed with a runic inscription based on the runic alphabet used by Germanic people in Northern Europe. Generally, the stone was raised and placed in specific places; some runestones were inscribed on boulders or bedrock. The inscriptions on the stone were brightly colored with paint. During Viking times in Sweden, runestones were carved and erected to depict people from Norse mythology. As Christianity increased, the runestone inscriptions had religious meanings. Gunnborga was the only female confirmed runemaster. The text on Hälsingland Rune Inscription 21, located by a church in Sweden, identified Gunnborga as the carver. The stone says, "Ásmundr and Farþegn erected this stone in memory of Þorketill of Vattrång, their father. Gunnborga the Good carved this stone." [6]
Bayeux Tapestry
Women in medieval times were also educated in embroidery and tapestry art, acceptable forms of art both in the home and the convent. Elite women did embroidery as a suitable occupation and pastime, while ordinary women embroidered for their families. Larger estates established workshops and hired local women, increasing production. By the time of the Norman conquest in 1066, there were many embroidery workshops in England, and English embroidery was famous throughout Europe.
The Bayeux Tapestry was based on England's conquest by William, Duke of Normandy, following the Battle of Hastings in 1066. The entire tapestry is seventy meters long. The images depict different stories and activities from the beginning of the battle, as the longships crossed the sea, to the installation of William on the throne. The immense work was commissioned in 1077 by Bishop Odo for the new cathedral in Bayeux. The tapestry tells the story of medieval England's ordinary people and the military. The details move from large castles to miniature helmets; everything is detailed in any scene. The large central panel is bordered by a small seven-centimeter border along the top, covered with real and imaginary animals.
Although it is called a tapestry, the work was embroidered on nine linen panels joined together. The embroidery was made with wool thread using guide marks. Scholars believe the guide marks were originally basic drawings for the pattern. The pictures in the different sections were used to educate the illiterate people about the war, battles, and conquest, a sort of newspaper. The wool thread was hand-dyed using local plants. Woad was used for different shades of blue, and Dyer's rocket was made yellow. Madder produced various red tones, including orange, pink, and brown. The embroidery stitches used in the tapestry are still used today, including the stem, chain, and split stitches. The couching stitch is often named the Bayeux stitch and is used to fill solid areas.
The combatants portrayed in the tapestry are identified by their customs; the Anglo-Saxons had mustaches, and the Normans had the habit of shaving the back of their heads. Guy I, Count of Ponthieu (3.2.11) is a small section of the tapestry depicting the messengers meeting with the count. Guy took Harold prisoner, and William sent messengers to tell Guy to release Harold. The small border strip portrays the processes of medieval agriculture. The death of King Harold at the Battle of Hastings (3.2.12) is part of the scene when King Harold is slain at the Battle of Hastings. The title states HIC HAROLD REX INTERFECTUS EST (Here, King Harold is killed). The coronation of Harold II of England (3.2.13) displays Harold's coronation as king after King Edward's death. King Harold received the orb and scepter denoting his kingship as courtiers surrounded him. The outline of the castle covers the king on his throne.
Interactive Element: The Bayeux Tapestry
A video outlining the masterpiece of embroidery in the Medieval Times.
[1] Flanagan, S. (1998). Hildegard of Bingen: A Visionary Life (2 nd ed.). London: Routledge. Retrieved from https://en.Wikipedia.org/wiki/Scivias
[2] Engelhardt, Christian Moritz (1818). Herrad von Landsperg, Aebtissin zu Hohenburg oder St. Odilien, im Elsaß, im zwölften Jahrhundert; und ihre Werk: Hortus deliciarum: ein Beytrag zur Geschichte der Wissenschaften, Literatur, Kunst, Kleidung, Waffen und Sitten des Mittelalters . Stuttgarts and Tubingen. Retrieved from https://en.Wikipedia.org/wiki/Herrad_of_Landsberg
[3] Retrieved from https://liberalarts.online/philosoph...-liberal-arts/
[4] Retrieved from https://www.brooklynmuseum.org/eascf...age_floor/ende
[5] Women in the Making: Early Medieval Signatures and Artists' Portraits (9th–12th c.)" , Reassessing the Roles of Women as 'Makers' of Medieval Art and Architecture , BRILL, pp. 393–427, 2012-01-01, doi : 10.1163/9789004228320_012 , ISBN<PHONE_NUMBER>320 . Retrieved from https://en.Wikipedia.org/wiki/Guda_(nun)
[6] Retrieved from http://www.365womenartists.com/2018/...11th-cent.html


8.10: Timur
Under Timur (1370 – 1405), Central Asia moved to the fore of world events. He developed a political arrangement that could harness the best attributes of each society, without the dangerous side effect of communal violence. The new political and military system was deeply ingrained in the political background of the Chagatai Khanate, and eliminated the Inju practice. Timur provided a framework for both societies to live in harmony.
Born in 1336, near Kesh in modern-day Uzbekistan, Timur was a product of the Turko-Mongol fusion. He descended from an aristocratic Mongol clan, but he was raised as a Muslim and spoke a Turkic language. A native to Transoxiana, he could not assert Genghis-Khanid legitimacy. Thus, he could not take the title of khan in his own right. Because he did not have the correct pedigree, he would have to earn it. So, he took the title of emir, meaning commander, and ruled through a Chagatayid puppet khan acting as a figurehead. He married into the family of Genghis Khan. By changing the law of descent, he could accommodate his children, who would be able to claim Genghis-Khanid legitimacy.
To strengthen the security of his position as emir, he constructed a system of support that ordered his political connections in a series of concentric rings.
- In his primary circle resided his family and close allies.
- The second ring consisted of loyal tribes and Timur’s own Barlas Clan, from which he traced his lineage.
- The third circle was made up of those peoples Timur had defeated on the battlefield. This way, the second and third rings balanced one another.
- The outermost bands included Timur’s hereditary professional administrators and bureaucrats, soldiers from the plains serving in his cavalry units, and finally the Persian urban and agricultural populations, from which he recruited his infantry and siege units.
Like many transitional figures in history, such as Suleiman the Magnificent, Timur bridged the medieval and modern worlds. He attempted to imitate Genghis Khan’s success in the field and designed a novel military machine that was well adapted to the environment in which he lived. His military was the product of a Turko-Mongol fusion, employing Turkic siege techniques and the Mongol cavalry. Unlike Genghis Khan, however, Timur increasingly combined his cavalry, siege, and infantry units, placing his heavy cavalry at the center of formations. His army also utilized an early form of artillery. He ventured to monopolize the market on gunpowder technology so that other powers could not benefit from it.
Timur was determined to keep his volatile army occupied, so they would not be a burden to the sedentary population in his realm. To promote peace at home and success in war aboard, he externalized the violence of the steppe and destroyed all of the other trade routes that bypassed his territory. Timur attempted to reactivate and dominate the Silk Road and diverted trade to his lands in order to help rebuild the cities that had been damaged from years of Mongol and nomad rule. He did not aim at permanent occupation or the creation of new states. He campaigned against the Golden Horde, Delhi Sultanate, and the Ottoman Empire, all in an effort to redirect trade in his direction.
From 1370 to 1385, he conquered and subdued Mogholistan to the northeast, with the aim of securing the core central land route of the Silk Road. (The Chagatai Khanate had already been divided into two parts by the 1340s, Transoxania in the west, and Mogholistan in the east.) Then he engaged the Golden Horde between 1385 and 1395 to divert trade to his lands. The Golden Horde had been the master of the northern trade route that bypassed Timur’s territory.
Timur showed his strategic genius in these expeditions. He defeated a steppe power on the steppe. He put the pieces of his army together so that he could take his enemies on in their arena and on their terms. In this manner, Timur crushed Tokhtamysh , leader of the Golden Horde, in 1395. During the course of this campaign, Timur destroyed their principal trade cities of Astrakhan and Sarai. As a result of the campaign, the Grand Duchy of Moscow was able to throw off the Mongol yoke and arise.
Timur raided into India from 1398 to 1399 and dealt a blow to the southern sea route that connected the Occident to the Orient. This expedition was primarily for looting, since he never intended to conquer and annex the territory of Nasir-ud-Din Mahmud Shah Tughlu q, the last member of the Tughluq Dynasty of the Delhi Sultanate. During this campaign, Timur’s tactical brilliance was on full display; he had an uncanny ability to adapt to any martial environment that he confronted. For instance, when threatened with a cavalry of war elephants, Timur responded by unleashing a pack of camels laden with incendiary material to charge the enemy lines. The rest was utter pandemonium among Nasir-ud-Din’s cavalry of elephants, who rampaged through the sultan’s own lines. Timur easily routed the sultan’s forces. When faced with the townspeople of Delhi rising up against their aggressors, Timur brutally sacked the capital of the sultanate and justified the violence in religious terms. His was a Muslim victory over the Hindu unbelievers of India.
In Timur’s final period of conquest, which lasted from 1400 to 1404, he campaigned against the Islamic far west, directing his army against the Ottomans. Actually, Timur had initially attempted to avoid conflict with the Ottomans, and even tried to negotiate with Bayezid I, the Ottoman Sultan, offering him part of Golden Horde’s territory west of Dnieper River.
As the Ottomans expanded to the east, they took control of some Turkmen tribes in eastern Anatolia already under the protection of Timur. The emir responded by taking some other Turkmen tribes under Ottoman suzerainty. A war of words ensued, as Timur bided his time, waiting for the perfect moment to attack. In 1402, as the Ottomans were preoccupied with campaigning against the Hungarians, he attacked. During the Battle of Ankara in 1402, Timur managed to convince many of the Ottoman forces to defect to his side. He captured the Ottoman sultan, who died in captivity three months later. Timur had not attempted to conquer the Ottomans. Rather, he just wanted to punish them for their unwillingness to cooperate. His Levantine expedition also seems to have been designed to weaken the western end of the Silk Road in Aleppo, Syria.
Timur died in 1405 while on a campaign against the Ming Dynasty in China. His empire had spanned the breadth of Central Asia. The sons of Timur and their followers squabbled over succession. As members of the Timurid Dynasty competed among themselves, the empire fragmented. The steppe military that had been redirected, returned on Timur's death. A weak state emerged from all this strife.
8.9.1: Terror and Destruction
Timur certainly committed what we would describe today as war crimes. In fact, as an admirer of architecture, he is known to have constructed pyramids of human skulls. Extant accounts describe him slaughtering 100,000 Indian prisoners following the Delhi uprising. But not all destruction was the same. Genghis Khan’s used terror as a method to protect his troops, whereas Timur engaged in terror and destruction for pleasure.
8.9.2: Legacy
A product of the Turko-Mongolian fusion, Timur had been the first to reunite the eastern and western parts of the Chagatai ulus. His empire represents the construction of the political boundaries that would define modern-day Central Asia up to the twentieth century. Under his rule, we see growing political and cultural distinctions between Iran, Central Asia proper, and India beginning to cement. In this context, we also witness a split taking place on the steppe that will lead to a differentiation of the Uzbeks and Kazaks. By the late fourteenth century, the tribes on the steppe to the north will become known to Muslim writers as Kazaks, whereas the tribes to the south will be increasingly referred to as Uzbeks.


7.1: Chronology
This chronology cover over 500 years of history. You do not need to memorize it. Rather, the list is provided for references purposes.
962 CE Otto I crowned Holy Roman Emperor
987 CE Hugh Capet elected king of France
c. 1000 – 1100 CE Emergence of Western European feudalism
1031 CE Fall of the Cordoba Caliphate
1049 CE Pope Leo IX begins papal efforts at Church reform
1054 CE Schism between the pope and the patriarch of Constantinople
1066 CE Norman Conquest of England
1071 CE Battle of Manzikert annihilates Byzantine field army
1077 CE Henry IV repents to Pope Gregory VII at Canossa
1085 CE Fall of Muslim Toledo to the Christian kingdom of Leon-Castile
1088 – 1231 CE Foundation of Universities of Bologna, Paris, Oxford, and Cambridge
1091 CE Norman conquest of Muslim Sicily complete
1095 CE Council of Clermont, calling of the First Crusade
1099 CE Fall of Jerusalem to Christian Crusaders, the establishment of Crusader States
1100 – 1135 CE King Henry I rules England
1118 – 1143 CE Emperor John II rules the Byzantine Empire
1122 CE Concordat of Worms
1125 – 1152 CE Raymond is archbishop of Toledo, begins sponsoring the translation of Muslim and Greek philosophy from Arabic into Latin
1143 – 1180 CE Emperor Manuel Komnenos rules the Byzantine Empire
1154 – 1189 CE King Henry II rules England
1176 CE Frederick Barbarossa defeated by Lombard League at the Battle of Legnano; Manuel Komnenos defeated by Saljuq Turks at the Battle of Myriokephalon
1187 CE Kingdom of Jerusalem defeated by Saladin at the Battle of Hattin; fall of Jerusalem; Pope Gregory VIII issues Audita tremendi, calling the Third Crusade
1189 – 1192 CE The Third Crusade, a rump (remnant of a larger government) the Christian Kingdom of Jerusalem is re-established, but Jerusalem remains in Muslim hands
1203 – 1226 CE France’s Capetian kings extend the control of lands directly ruled by the crown
1204 CE Crusaders sack Constantinople, break-up of the Byzantine Empire
1212 CE Almohad Caliphate defeated by Spanish Christian kingdoms at the Battle of Las Navas de Tolosa
1215 CE Magna Carta
1215 – 1250 CE Frederick II is Holy Roman Emperor
1224 – 1274 CE Life of St. Thomas Aquinas
1229 CE A treaty between Frederick II and Egyptian sultan al-Kamil returns Jerusalem to Christian rule
1240 CE Mongol Conquest of Kievan Rus
1241 CE Mongol invasion of Hungary
1244 CE Jerusalem falls to Ayyubid Egypt
1248 – 1254 CE The Seventh Crusade; France’s King Louis IX defeated by Egypt; Egyptian Mamluk coup d’état
1250 – 1273 CE There is no Holy Roman Emperor
1261 CE Restoration of the Byzantine Empire
1291 CE Last Crusader territory in the Levant falls to Mamluk Egypt
c. 1300 CE Genoese sailors begin exploring the Atlantic Ocean
early 1300s CE Genoese sailors are visiting the Canary Islands
1309 CE Beginning of Avignon papacy
1314 – 1326 CE Civil war in the Holy Roman Empire
1315 – 1322 CE The Great Famine
1324 CE Mansa Musa’s hajj
1331 CE Nearly all Byzantine territory in Asia Minor has fallen to the Ottoman Turks
1337 CE The Hundred Years’ War begins
c. 1350 CE Beginning of Italian Renaissance and Humanism
1347 – 1351 CE The Black Death, nearly a third of Europe’s population dies
1356 CE The Holy Roman Empire becomes an elected monarchy
1358 CE French peasant revolt
1378 CE Beginning of Great Schism
1385 CE Lithuania united with Poland, Lithuanian monarch converts to Christianity
1396 CE Ottoman Turks conquer Bulgaria
1397 CE Union of Kalmar unites Sweden, Denmark, and Norway under a single crown
c. 1400 – 1500 CE Renaissance Humanism spreads throughout Europe
1404 CE Castilian effort to conquer the Canaries begins
1415 – 1417 CE Council of Constance resolves the Great Schism
1440 CE Lorenzo Valla shows the Donation of Constantine to be a forgery
mid 1400s CE Iberians are settling the Azores, a plantation economy worked by African slaves begins to flourish in the Canaries and Azores
1453 CE Ottoman conquest of Constantinople, final fall of the Byzantine Empire; End of Hundred Years’ War and English attempts to conquer France
1454 CE Treaty of Lodi brings nearly a half-century of peace to Italy
1455 – 1485 CE Wars of the Roses in England
1459 CE Final Ottoman conquest of Serbia
1479 CE Marriage of Queen Isabella of Castile and Ferdinand of Aragon creates a united Spanish monarchy
1492 CE King Ferdinand and Queen Isabella complete the Reconquista with the conquest of Granada; Christopher Columbus, sailing for the Spanish crown, makes landfall in the Western Hemisphere
1494 CE France invades Italy


3: The Cell
In the 17th century, observations of microscopic life led to the development of the cell theory: the idea that the fundamental unit of life is the cell, that all organisms contain at least one cell, and that cells only come from other cells. Despite sharing certain characteristics, cells may vary significantly. The two main types of cells are prokaryotic cells (lacking a nucleus) and eukaryotic cells (containing a well-organized, membrane-bound nucleus). Each type of cell exhibits remarkable variety in structure, function, and metabolic activity. This chapter will focus on the historical discoveries that have shaped our current understanding of microbes, including their origins and their role in human disease. We will then explore the distinguishing structures found in prokaryotic and eukaryotic cells.
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- 3.0: Spontaneous Generation
- The theory of spontaneous generation states that life arose from nonliving matter. It was a long-held belief dating back to Aristotle and the ancient Greeks. Experimentation by Francesco Redi in the 17th century presented the first significant evidence refuting spontaneous generation by showing that flies must have access to meat for maggots to develop on the meat. Louis Pasteur is credited with conclusively disproving the theory and proposed that “life only comes from life.”
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- 3.1: Foundations of Modern Cell Theory
- Although cells were first observed in the 1660s by Robert Hooke, cell theory was not well accepted for another 200 years. The work of scientists such as Schleiden, Schwann, Remak, and Virchow contributed to its acceptance. Endosymbiotic theory states that mitochondria and chloroplasts, organelles found in many types of organisms, have their origins in bacteria. Significant structural and genetic information support this theory. The miasma theory was widely accepted until the 19th century.
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- 3.2: Unique Characteristics of Prokaryotic Cells
- Prokaryotic cells differ from eukaryotic cells in that their genetic material is contained in a nucleoid rather than a membrane-bound nucleus. In addition, prokaryotic cells generally lack membrane-bound organelles. Prokaryotic cells of the same species typically share a similar cell morphology and cellular arrangement. Most prokaryotic cells have a cell wall that helps the organism maintain cellular morphology and protects it against changes in osmotic pressure.
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- 3.3: Unique Characteristics of Eukaryotic Cells
- Eukaryotic cells are defined by the presence of a nucleus containing the DNA genome and bound by a nuclear membrane (or nuclear envelope) composed of two lipid bilayers that regulate transport of materials into and out of the nucleus through nuclear pores. Eukaryotic cell morphologies vary greatly and may be maintained by various structures, including the cytoskeleton, the cell membrane, and/or the cell wall The nucleolus in the nucleus of eukaryotic cells is the site of ribosomal synthesis.
Thumbnail: A 3D rendering of an animal cell cut in half. Image used with permission (CC -BY-SA 4.0; Zaldua I., Equisoain J.J., Zabalza A., Gonzalez E.M., Marzo A., Public University of Navarre).


4.5: Checklist - Obtain a Blood Sample From a CVAD
*Disclaimer: Always follow agency policy and manufacturer recommendations
Checklist: Obtain a Blood Sample From a CVAD [1] , [2]
- Verify the provider’s order.
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Gather the necessary equipment:
- Gloves
- 10-mL prefilled syringes containing preservative-free normal saline flush solution (or syringes specifically designed to generate lower injection pressure)
- Antiseptic pads or scrubs (chlorhexidine-based, povidone-iodine, or alcohol)
- Appropriately sized syringes or needleless blood collection tube holder
- Blood collection tubes
- Labels
- Laboratory biohazard transport bag
- Puncture-resistant sharps disposal container
- Perform hand hygiene.
- Confirm the client’s identity using at least two patient identifiers and check allergies.
- Provide privacy.
- Explain the procedure to the client and family (if appropriate) and answer any questions.
- Put on gloves and, if splashing is likely, put on a mask with a face shield or a mask and goggles.
- Raise the bed to waist level when providing care.
- Trace the tubing from the client to its point of origin.
- Stop any infusing IV fluids, including those running through another lumen of the catheter. Follow agency policy for how long the IV fluids must be stopped before the blood draw. Clamp the lumen, if appropriate. Detach the administration set from the needleless connector and place a sterile cap over the end of the administration set, if necessary.
- If no IV fluids are infusing and an antiseptic-impregnated sterile cap is covering the end of the needleless connector, replace it according to agency policy. For example, if drawing blood for blood cultures, agencies may require changing the cap before the blood draw to prevent contamination of blood culture results.
- Perform a vigorous mechanical scrub of the needleless connector for at least 15 seconds using an antiseptic pad. Allow it to air dry; do not fan or wave over it.
- While maintaining sterility of the syringe tip, attach a prefilled syringe containing preservative-free normal saline solution to the needleless connector. Unclamp the catheter and slowly aspirate for blood return. Troubleshoot if no blood return occurs; notify the practitioner if troubleshooting is ineffective.
- If blood return occurs, slowly inject the preservative-free normal saline solution into the catheter.
- Using the attached syringe used for flushing, aspirate the same volume of blood as amount of saline used to flush the catheter.
- Clamp the catheter and remove and discard the blood collection tube or syringe.
- Perform a vigorous mechanical scrub of the needleless connector for at least 15 seconds using an antiseptic pad, allow it to dry, connect an empty syringe to the catheter, release the clamp, and withdraw the blood sample.
- Clamp the catheter and remove the syringe.
- Change the needleless connector according to the manufacturer’s instructions.
- Perform a vigorous mechanical scrub of the needleless connector for at least five seconds using an antiseptic pad; allow it to dry.
- While maintaining sterility of the syringe tip, attach the syringe containing preservative-free normal saline solution.
- Unclamp the catheter, slowly inject the preservative-free normal saline solution into the catheter, and then reclamp the catheter.
- Remove and discard the syringe.
- Continue the client’s prescribed continuous IV infusion; if the client doesn’t have a continuous infusion prescribed, proceed with locking the device if required by the facility. Discard the syringe.
- Place a new antiseptic-impregnated sterile cap, if available at the facility, on the needleless connector after locking it with saline.

- Label the samples in the presence of the client.
- Place all blood collection tubes in a laboratory biohazard transport bag and send them to the laboratory with a completed laboratory request form.
- Dispose of used equipment in appropriate receptacles.
- Remove and discard gloves and other personal protective equipment.
- Perform hand hygiene.
- In an inpatient setting, help the client into a comfortable position and place personal items, the tray table, and the call light within easy reach. Make sure the client knows how to use the call light to summon assistance. To ensure the client’s safety, raise the appropriate number of side rails and lower the bed to the lowest position. Ensure the bed is locked.
- Perform hand hygiene.
- Document the procedure and assessments.
Documentation Cues:
- Date and time the blood sample was drawn
- Volume of blood withdrawn
- Lumen used if the client has a multi-lumen central venous access catheter
- Laboratory tests for which the sample was drawn
- Time the sample was sent to the laboratory
- Assessment of the catheter exit site and the patency of the catheter
- Absence of signs and symptoms of complications
- Presence of blood return on aspiration
- Lack of resistance when flushing
- Amount and types of flushes used
- Teaching provided to the client and family (if applicable), understanding, and follow-up teaching needed
View a YouTube video [3] showing an instructor demonstration of this skill:
- Clinical skills: Essentials collection (1st ed.). (2021). Elsevier. ↵
- Lippincott procedures. http://procedures.lww.com ↵
- Chippewa Valley Technical College. (2023, January 5). Obtaining a blood sample from a central venous access device (CVAD) [Video]. YouTube. Video licensed under CC BY 4.0 . ↵


11.1.5D: The Psychological Perspective
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Learning Objectives
- Describe how the psychological perspective views race and ethnicity
One of the most important social psychological findings concerning race relations is that members of stereotyped groups internalize those stereotypes and thus suffer a wide range of harmful consequences.
Stereotype Threat is the experience of anxiety or concern in a situation where a person has the potential to confirm a negative stereotype about their social group. Since its introduction into the academic literature in 1995, Stereotype Threat has become one of the most widely studied topics in the field of social psychology. First described by social psychologist, Claude Steele and his colleagues, Stereotype Threat has been shown to reduce the performance of individuals who belong to negatively stereotyped groups. If negative stereotypes are present regarding a specific group, they are likely to become anxious about their performance, which in turn may hinder their ability to perform at their maximum level.
Stereotype Threat is a potential contributing factor to long-standing racial and gender gaps in academic performance. However, it may occur whenever an individual’s performance might confirm a negative stereotype. This is because Stereotype Threat is thought to arise from the particular situation rather than from an individual’s personality traits or characteristics. Since most people have at least one social identity which is negatively stereotyped, most people are vulnerable to Stereotype Threat if they encounter a situation in which the stereotype is relevant.
Situational factors that increase Stereotype Threat can include the difficulty of the task, the belief that the task measures their abilities, and the relevance of the negative stereotype to the task. Individuals show higher degrees of Stereotype Threat on tasks they wish to perform well on and when they identify strongly with the stereotyped group. These effects are also increased when they expect discrimination due to their identification with negatively stereotyped group. Repeated experiences of Stereotype Threat can lead to a vicious circle of diminished confidence, poor performance, and loss of interest in the relevant area of achievement.
The opposite of Stereotype Threat is known as Stereotype Enhancement, which entails an individual’s potential to confirm a positive stereotype about their social group, and a subsequent increase in performance ability in the related task as compared to their ability prior to their exposure to the stereotype.
Advocates of Stereotype Threat explanation have been criticized for exaggerating it and for misrepresenting evidence as more conclusive than it is.
Key Points
- Stereotype Threat is the experience of anxiety or concern in a situation where a person has the potential to confirm a negative stereotype about their social group.
- If negative stereotypes are present regarding a specific group, they are likely to become anxious about their performance which may hinder their ability to perform at their maximum level.
- Stereotype Threat is a potential contributing factor to long-standing racial and gender gaps in academic performance.
- Advocates of Stereotype Threat explanation have been criticized for exaggerating the importance of stereotype threat and for misrepresenting evidence as more conclusive than it is.
Key Terms
- internalize : To make something internal; to incorporate it in oneself.
- stereotype threat : The anxiety or stress a person experiences when they find themselves in a situation in which they could potentially confirm a negative stereotype about their social group.
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5.7: Multiple Eigenvalues
It may very well happen that a matrix has some “repeated” eigenvalues. That is, the characteristic equation \(\det(A-\lambda I)=0\) may have repeated roots. As we have said before, this is actually unlikely to happen for a random matrix. If we take a small perturbation of \(A\) (we change the entries of \(A\) slightly), then we will get a matrix with distinct eigenvalues. As any system we will want to solve in practice is an approximation to reality anyway, it is not indispensable to know how to solve these corner cases. On the other hand, these cases do come up in applications from time to time. Furthermore, if we have distinct but very close eigenvalues, the behavior is similar to that of repeated eigenvalues, and so understanding that case will give us insight into what is going on.
Geometric Multiplicity
Take the diagonal matrix
\[ A = \begin{bmatrix}3&0\\0&3 \end{bmatrix} \nonumber \]
\(A\) has an eigenvalue \(3\) of multiplicity \(2\). We call the multiplicity of the eigenvalue in the characteristic equation the algebraic multiplicity . In this case, there also exist \(2\) linearly independent eigenvectors, \(\begin{bmatrix}1\\0 \end{bmatrix}\) and \(\begin{bmatrix} 0\\1 \end{bmatrix}\) corresponding to the eigenvalue \(3\). This means that the so-called geometric multiplicity of this eigenvalue is also \(2\).
In all the theorems where we required a matrix to have \(n\) distinct eigenvalues, we only really needed to have \(n\) linearly independent eigenvectors. For example, \(\vec{x} = A \vec{x} \) has the general solution
\[\vec{x} = c_1 \begin{bmatrix} 1\\0 \end{bmatrix} e^{3t} + c_2 \begin{bmatrix} 0\\1 \end{bmatrix} e^{3t}. \nonumber \]
T he geometric multiplicity of an eigenvalue of algebraic multiplicity n is equal to the number of corresponding linearly independent eigenvectors . The geometric multiplicity is always less than or equal to the algebraic multiplicity. We have handled the case when these two multiplicities are equal. If the geometric multiplicity is equal to the algebraic multiplicity, then we say the eigenvalue is complete .
In other words, the hypothesis of the theorem could be stated as saying that if all the eigenvalues of \(P\) are complete, then there are \(n\) linearly independent eigenvectors and thus we have the given general solution.
If the geometric multiplicity of an eigenvalue is \(2\) or greater, then the set of linearly independent eigenvectors is not unique up to multiples as it was before. For example, for the diagonal matrix \(A = \begin{bmatrix} 3&0 \\ 0&3 \end{bmatrix} \) we could also pick eigenvectors \(\begin{bmatrix} 1\\1 \end{bmatrix} \) and \( \begin{bmatrix} 1\\-1 \end{bmatrix} \) , or in fact any pair of two linearly independent vectors. The number of linearly independent eigenvectors corresponding to \(\lambda\) is the number of free variables we obtain when solving \(A\vec{v} = \lambda \vec{v} \) . We pick specific values for those free variables to obtain eigenvectors. If you pick different values, you may get different eigenvectors.
Defective Eigenvalues
If an \(n \times n\) matrix has less than n linearly independent eigenvectors, it is said to be deficient . Then there is at least one eigenvalue with an algebraic multiplicity that is higher than its geometric multiplicity. We call this eigenvalue defective and the difference between the two multiplicities we call the defect .
The next theorem shows what to do in this situation.
Suppose the \(n\times n\) matrix \(A\) has an eigenvalue \(\lambda_1\) of multiplicity \(\ge2\) and the associated eigenspace has dimension \(1;\) that is\(,\) all \(\lambda_1\)-eigenvectors of \(A\) are scalar multiples of an eigenvector \({\bf x}.\) Then there are infinitely many vectors \({\bf u}\) such that
\[\label{eq:10.5.2} (A-\lambda_1I){\bf u}={\bf x}.\]
Moreover\(,\) if \({\bf u}\) is any such vector then
\[\label{eq:10.5.3} {\bf y}_1={\bf x}e^{\lambda_1t}\quad\mbox{and }\quad {\bf y}_2={\bf u}e^{\lambda_1t}+{\bf x}te^{\lambda_1t}\]
are linearly independent solutions of \({\bf y}'=A{\bf y}.\)
Use Theorem 5.7.1 to find the general solution of the system
\[\label{eq:10.5.6} {\bf y}'=\left[\begin{array}{cc}{11}&{-25}\\{4}&{-9}\end{array} \right]{\bf y}\]
considered in Example 5.7.1 .
Solution
In Example 5.7.1 we saw that \(\lambda_1=1\) is an eigenvalue of multiplicity \(2\) of the coefficient matrix \(A\) in Equation \ref{eq:10.5.6}, and that all of the eigenvectors of \(A\) are multiples of
\[{\bf x}=\begin{bmatrix} 5 \\ 2 \end{bmatrix}.\nonumber\]
Therefore
\[{\bf y}_1=\begin{bmatrix} 5 \\ 2 \end{bmatrix}e^t\nonumber\]
is a solution of Equation \ref{eq:10.5.6}. From Theorem 5.7.1 , a second solution is given by \({\bf y}_2={\bf u}e^t+{\bf x}te^t\), where \((A-I){\bf u}={\bf x}\). The augmented matrix of this system is
\[\left[\begin{array}{rrcr}10&-25&\vdots&5\\4&-10&\vdots&2\end{array}\right],\nonumber\]
which is row equivalent to
\[\left[\begin{array}{rrcr}1&-\frac{5}{2}&\vdots&\frac{1}{2}\\0&0&\vdots&0\end{array}\right],\nonumber\]
Therefore the components of \({\bf u}\) must satisfy
\[u_1-{5\over2}u_2={1\over2},\nonumber\]
where \(u_2\) is arbitrary. We choose \(u_2=0\), so that \(u_1=1/2\) and
\[{\bf u}=\begin{bmatrix} 1\over2 \\ 0 \end{bmatrix}.\nonumber\]
Thus,
\[{\bf y}_2=\begin{bmatrix} 1 \\ 0 \end{bmatrix}{e^t\over2}+\begin{bmatrix} 5 \\ 2 \end{bmatrix}te^t.\nonumber\]
Since \({\bf y}_1\) and \({\bf y}_2\) are linearly independent by Theorem 5.7.1 , they form a fundamental set of solutions. Therefore the general solution is
\[{\bf y}=c_1\begin{bmatrix} 5 \\ 2 \end{bmatrix}e^t+c_2\left(\begin{bmatrix} 1 \\ 0 \end{bmatrix}{e^t\over2}+\begin{bmatrix} 5 \\ 2 \end{bmatrix}te^t\right).\nonumber\]
Note that choosing the arbitrary constant \(u_2\) to be nonzero is equivalent to adding a scalar multiple of \({\bf y}_1\) to the second solution \({\bf y}_2\) ( Exercise 10.5.33 ).
Find the general solution of
\[\label{eq:10.5.7} {\bf y}'=\left[\begin{array}{ccc}{3}&{4}&{-10}\\{2}&{1}&{-2}\\{2}&{2}&{-5}\end{array} \right] {\bf y}.\]
Solution
The characteristic polynomial of the coefficient matrix \(A\) in Equation \ref{eq:10.5.7} is
\[\left|\begin{array}{ccc} 3-\lambda & 4 & -10\\ 2 & 1-\lambda & -2\\ 2 & 2 &-5-\lambda\end{array}\right| =- (\lambda-1)(\lambda+1)^2.\nonumber\]
Hence, the eigenvalues are \(\lambda_1=1\) with multiplicity \(1\) and \(\lambda_2=-1\) with multiplicity \(2\). Eigenvectors associated with \(\lambda_1=1\) must satisfy \((A-I){\bf x}={\bf 0}\). The augmented matrix of this system is
\[\left[\begin{array}{rrrcr} 2 & 4 & -10 &\vdots & 0\\ 2& 0 & -2 &\vdots & 0\\ 2 & 2 & -6 & \vdots & 0\end{array}\right],\nonumber\]
which is row equivalent to
\[\left[\begin{array}{rrrcr} 1 & 0 & -1 &\vdots& 0\\ 0 & 1 & -2 &\vdots& 0\\ 0 & 0 & 0 &\vdots&0\end{array}\right].\nonumber\]
Hence, \(x_1 =x_3\) and \(x_2 =2 x_3\), where \(x_3\) is arbitrary. Choosing \(x_3=1\) yields the eigenvector
\[{\bf x}_1=\begin{bmatrix} 1 \\ 2 \\ 1 \end{bmatrix} .\nonumber\]
Therefore
\[{\bf y}_1 =\begin{bmatrix} 1 \\ 2 \\ 1 \end{bmatrix} e^t\nonumber\]
is a solution of Equation \ref{eq:10.5.7}. Eigenvectors associated with \(\lambda_2 =-1\) satisfy \((A+I){\bf x}={\bf 0}\). The augmented matrix of this system is
\[\left[\begin{array}{rrrcr} 4 & 4 & -10 &\vdots & 0\\ 2 & 2 & -2 & \vdots & 0\\2 & 2 & -4 &\vdots & 0\end{array}\right],\nonumber\]
which is row equivalent to
\[\left[\begin{array}{rrrcr} 1 & 1 & 0 &\vdots& 0\\ 0 & 0 & 1 &\vdots& 0 \\ 0 & 0 & 0 &\vdots&0\end{array}\right].\nonumber\]
Hence, \(x_3=0\) and \(x_1 =-x_2\), where \(x_2\) is arbitrary. Choosing \(x_2=1\) yields the eigenvector
\[{\bf x}_2=\begin{bmatrix} -1 \\ 1 \\ 0 \end{bmatrix} ,\nonumber\]
so
\[{\bf y}_2 =\begin{bmatrix} -1 \\ 1 \\ 0 \end{bmatrix} e^{-t}\nonumber\]
is a solution of Equation \ref{eq:10.5.7}. Since all the eigenvectors of \(A\) associated with \(\lambda_2=-1\) are multiples of \({\bf x}_2\), we must now use Theorem 5.7.1 to find a third solution of Equation \ref{eq:10.5.7} in the form
\[\label{eq:10.5.8} {\bf y}_3={\bf u}e^{-t}+\begin{bmatrix} -1 \\ 1 \\ 0 \end{bmatrix} te^{-t},\]
where \({\bf u}\) is a solution of \((A+I){\bf u=x}_2\). The augmented matrix of this system is
\[\left[\begin{array}{rrrcr} 4 & 4 & -10 &\vdots & -1\\ 2 & 2 & -2 & \vdots & 1\\ 2 & 2 & -4 &\vdots & 0\end{array}\right],\nonumber\]
which is row equivalent to
\[\left[\begin{array}{rrrcr} 1 & 1 & 0 &\vdots& 1\\ 0 & 0 & 1 &\vdots& {1\over2} \\ 0 & 0 & 0 &\vdots&0\end{array}\right].\nonumber\]
Hence, \(u_3=1/2\) and \(u_1 =1-u_2\), where \(u_2\) is arbitrary. Choosing \(u_2=0\) yields
\[{\bf u} =\begin{bmatrix} 1 \\ 0 \\ 1\over2 \end{bmatrix} ,\nonumber\]
and substituting this into Equation \ref{eq:10.5.8} yields the solution
\[{\bf y}_3=\begin{bmatrix} 2 \\ 0 \\ 1 \end{bmatrix} {e^{-t}\over2}+\begin{bmatrix} -1 \\ 1 \\ 0 \end{bmatrix} te^{-t}\nonumber\]
of Equation \ref{eq:10.5.7}. Since the Wronskian of \(\{{\bf y}_1,{\bf y}_2,{\bf y}_3\}\) at \(t=0\) is
\[\left|\begin{array}{rrr} 1&-1&1\\2&1&0\\1&0&1\over2\end{array}\right|={1\over2},\nonumber\]
\(\{{\bf y}_1,{\bf y}_2,{\bf y}_3\}\) is a fundamental set of solutions of Equation \ref{eq:10.5.7}. Therefore the general solution of Equation \ref{eq:10.5.7} is
\[{\bf y}=c_1\begin{bmatrix} 1 \\ 2 \\ 1 \end{bmatrix} e^t+c_2\begin{bmatrix} -1 \\ 1 \\ 0 \end{bmatrix} e^{-t}+c_3\left (\begin{bmatrix} 2 \\ 0 \\ 1 \end{bmatrix} {e^{-t}\over2}+\begin{bmatrix} -1 \\ 1 \\ 0 \end{bmatrix} e^{-t}\right).\nonumber\]
Below is a video on solving a defective system of differential equations.
Note that the system \( \vec{x}' = A \vec{x} \) has a simpler solution since \(A\) is a so-called upper triangular matrix , that is every entry below the diagonal is zero. In particular, the equation for \( x_2 \) does not depend on \(x_1\). Mind you, not every defective matrix is triangular.
Solve \( \vec{x}' = \begin{bmatrix} 3&1\\ 0&3 \end{bmatrix} \vec{x} \) by first solving for \(x_2\) and then for \( x_1 \) independently. Check that you got the same solution as we did above.
Let us describe the general algorithm. Suppose that \(\lambda \) is an eigenvalue of multiplicity \(2\), defect \(1\). First find an eigenvector \(\vec{v_1} \) of \( \lambda\). Then, find a vector \( \vec{v_2} \) such that
\[ (A - \lambda I) \vec{v_2} = \vec{v_1} \nonumber \]
This gives us two linearly independent solutions
\[\begin{align}\begin{aligned} \vec{x_1} &= \vec{v_1} e^{\lambda t} \\ \vec{x_2} &= (\vec{v_2} + \vec{v_1} t )e^{\lambda t }\end{aligned}\end{align} \nonumber \]
Consider the system \[\vec{x}' = \begin{bmatrix} 2 & -5 & 0 \\ 0 & 2 & 0 \\ -1 & 4 & 1 \end{bmatrix} \vec{x} . \nonumber \] Compute the eigenvalues,
Solution
\[0 = \det(A-\lambda I) = \det\left( \begin{bmatrix} 2-\lambda & -5 & 0 \\ 0 & 2-\lambda & 0 \\ -1 & 4 & 1-\lambda \end{bmatrix} \right) = (2-\lambda)^2(1-\lambda) . \nonumber \] The eigenvalues are 1 and 2, where 2 has multiplicity 2. We leave it to the reader to find that \(\left[ \begin{smallmatrix} 0 \\ 0 \\ 1 \end{smallmatrix} \right]\) is an eigenvector for the eigenvalue \(\lambda = 1\).
Let’s focus on \(\lambda = 2\). We compute eigenvectors: \[\vec{0} = (A - 2 I) \vec{v} = \begin{bmatrix} 0 & -5 & 0 \\ 0 & 0 & 0 \\ -1 & 4 & -1 \end{bmatrix} \begin{bmatrix} v_1 \\ v_2 \\ v_3 \end{bmatrix} . \nonumber \] The first equation says that \(v_2 = 0\), so the last equation is \(-v_1 -v_3 = 0\). Let \(v_3\) be the free variable to find that \(v_1 = -v_3\). Perhaps let \(v_3 = -1\) to find an eigenvector \(\left[ \begin{smallmatrix} 1 \\ 0 \\ -1 \end{smallmatrix} \right]\). Problem is that setting \(v_3\) to anything else just gets multiples of this vector and so we have a defect of 1. Let \(\vec{v}_1\) be the eigenvector and let’s look for a generalized eigenvector \(\vec{v}_2\): \[(A - 2 I) \vec{v}_2 = \vec{v}_1 , \nonumber \] or \[\begin{bmatrix} 0 & -5 & 0 \\ 0 & 0 & 0 \\ -1 & 4 & -1 \end{bmatrix} \begin{bmatrix} a \\ b \\ c \end{bmatrix} = \begin{bmatrix} 1 \\ 0 \\ -1 \end{bmatrix} , \nonumber \] where we used \(a\), \(b\), \(c\) as components of \(\vec{v}_2\) for simplicity. The first equation says \(-5b = 1\) so \(b = \frac{-1}{5}\). The second equation says nothing. The last equation is \(-a + 4b - c = -1\), or \(a + \frac{4}{5} + c = 1\), or \(a + c = \frac{1}{5}\). We let \(c\) be the free variable and we choose \(c=0\). We find \(\vec{v}_2 = \left[ \begin{smallmatrix} \frac{1}{5} \\ \frac{-1}{5} \\ 0 \end{smallmatrix} \right]\).
The general solution is therefore, \[\vec{x} = c_1 \begin{bmatrix} 0 \\ 0 \\ 1 \end{bmatrix} e^t + c_2 \begin{bmatrix} 1 \\ 0 \\ -1 \end{bmatrix} e^{2t} + c_3 \left( \begin{bmatrix} \frac{1}{5} \\ \frac{-1}{5} \\ 0 \end{bmatrix} + \begin{bmatrix} 1 \\ 0 \\ -1 \end{bmatrix} t \right) e^{2t} . \nonumber \]
This machinery can also be generalized to higher multiplicities and higher defects. We will not go over this method in detail, but let us just sketch the ideas. Suppose that \(A\) has an eigenvalue \( \lambda \) of multiplicity \(m\). We find vectors such that
Such vectors are called generalized eigenvectors (then \(\vec{v_{1}}=(A-\lambda I)^{k-1}\vec{v}\) is an eigenvector) . For every eigenvector \(\vec{v}_{1} \) we find a chain of generalized eigenvectors \( \vec{v}_{2} \) through \(\vec{v}_{k} \) such that:
\[\begin{align}\begin{aligned} (A - \lambda I) \vec{v_1} &= \vec{0}, \\ (A - \lambda I)\vec{v_2} &= \vec{v_1}, \\ &\vdots \\ (A - \lambda I )\vec{v_k} &= \vec{v_{k-1}}. \end{aligned}\end{align} \nonumber \]
Really once you find the \(\vec{v}_k\) such that \({(A - \lambda I)}^k \vec{v}_k = \vec{0}\) but \({(A - \lambda I)}^{k-1} \vec{v}_k \not= \vec{0}\), you find the entire chain since you can compute the rest, \(\vec{v}_{k-1} = (A - \lambda I) \vec{v}_k\), \(\vec{v}_{k-2} = (A - \lambda I) \vec{v}_{k-1}\), etc. We form the linearly independent solutions
\[\begin{align}\begin{aligned} \vec{x_1} &= \vec{v_1} e^{\lambda t} \\ \vec{x_2} &= ( \vec{v_2} + \vec{v_1} t) e^{\lambda t } \\ & \vdots \\ \vec{x_k} &= \left( \vec{v_k}+ \vec{v}_{k-1} t + \vec{v}_{k-2} \frac{t^2}{2} + \cdots + \vec{v}_{2} \frac{t^{k-2}}{(k-2)!} + \vec{v}_{1}\frac{t^{k-1}}{(k-1)!} ) e^{\lambda t} \right) \end{aligned}\end{align} \nonumber \]
Recall that \(k! = 1 \cdot 2 \cdot 3 \cdots (k-1) \cdot k\) is the factorial. If you have an eigenvalue of geometric multiplicity \(\ell\), you will have to find \(\ell\) such chains (some of them might be short: just the single eigenvector equation). We go until we form \(m\) linearly independent solutions where \(m\) is the algebraic multiplicity. We don’t quite know which specific eigenvectors go with which chain, so start by finding \(\vec{v}_k\) first for the longest possible chain and go from there.
For example, if \(\lambda\) is an eigenvalue of \(A\) of algebraic multiplicity \(3\) and defect \(2\), then solve \[(A - \lambda I) \vec{v}_1 = \vec{0} , \qquad (A - \lambda I) \vec{v}_2 = \vec{v}_1 , \qquad (A - \lambda I) \vec{v}_3 = \vec{v}_2 . \nonumber \] That is, find \(\vec{v}_3\) such that \({(A - \lambda I)}^3 \vec{v}_3 = \vec{0}\), but \({(A - \lambda I)}^2 \vec{v}_3 \not= \vec{0}\). Then you are done as \(\vec{v}_2 = (A - \lambda I) \vec{v}_3\) and \(\vec{v}_1 = (A - \lambda I) \vec{v}_2\). The 3 linearly independent solutions are \[\vec{x}_1 = \vec{v}_1 e^{\lambda t} , \qquad \vec{x}_2 = ( \vec{v}_2 + \vec{v}_1 t ) \, e^{\lambda t} , \qquad \vec{x}_3 = \left( \vec{v}_3 + \vec{v}_2 t + \vec{v}_{1} \frac{t^2}{2} \right) \, e^{\lambda t} . \nonumber \]
If on the other hand \(A\) has an eigenvalue \(\lambda\) of algebraic multiplicity \(3\) and defect \(1\), then solve \[(A - \lambda I) \vec{v}_1 = \vec{0} , \qquad (A - \lambda I) \vec{v}_2 = \vec{0} , \qquad (A - \lambda I) \vec{v}_3 = \vec{v}_2 . \nonumber \] Here \(\vec{v}_1\) and \(\vec{v}_2\) are actual honest eigenvectors, and \(\vec{v}_3\) is a generalized eigenvector. So there are two chains. To solve, first find a \(\vec{v}_3\) such that \({(A - \lambda I)}^2 \vec{v}_3 = \vec{0}\), but \((A - \lambda I) \vec{v}_3 \not= \vec{0}\). Then \(\vec{v}_2 = (A - \lambda I) \vec{v}_3\) is going to be an eigenvector. Then solve for an eigenvector \(\vec{v}_1\) that is linearly independent from \(\vec{v}_2\). You get 3 linearly independent solutions \[\vec{x}_1 = \vec{v}_1 e^{\lambda t} , \qquad \vec{x}_2 = \vec{v}_2 e^{\lambda t} , \qquad \vec{x}_3 = ( \vec{v}_3 + \vec{v}_2 t ) \, e^{\lambda t} . \nonumber \]


6.7: §51. Chapter 6- Exercises
1. By using one of the suffixes -(I)TAS , -ITUDO , or -ITIA , form a Latin abstract noun from each of the following Latin adjectives, and then show the English noun derivative:
| Latin adjective | Latin noun | English noun | |
| e.g. | dignus (worthy) | dignitas | dignity (also dainty ) |
| a. | severus (stern) | __________________ | ____________________ |
| b. | beatus (blessed) | __________________ | ____________________ |
| c. | avarus (greedy) | __________________ | ____________________ |
| d. | socius (allied) | __________________ | ____________________ |
| e. | integer (whole) | __________________ | ____________________ |
| f. | aptus (fit) | __________________ | ____________________ |
2. The following English abstract nouns are of Germanic origin; can you think of parallel English nouns (semantic and structural counterparts) derived from Latin?
| Nouns in -(I)TY (< -(I)TAS) | Nouns in -ITUDE (< -ITUDO) | ||||
| a. | freedom | _______________ | f. | height | _______________ |
| b. | wordiness | _______________ | g. | breadth | _______________ |
| c. | stillness | _______________ | h. | strength | _______________ |
| d. | darkness | _______________ | i. | loneliness | _______________ |
| e. | ripeness | _______________ | j. | greatness | _______________ |
3. Look up the etymology of the English word city , and write down the main stages in its evolution from the original Latin root:
_____________________________________________________________________
_____________________________________________________________________
4. The following English nouns have been disguised during their transmission through French. Find the Latin abstract noun and Latin adjective from which each is derived:
| Latin Abstract Noun | Latin Adjective | (meaning) | ||||
| a. | < | poverty | __________ | < | __________ | __________ |
| b. | < | bounty | __________ | < | __________ | __________ |
| c. | < | dainty | __________ | < | __________ | __________ |
| d. | < | frailty | __________ | < | __________ | __________ |
5. Give a schematic analysis for each of the following words:
| e.g. | vitality | < L vitalitas : noun base vit – ( vita , “life”) + adj. suffix – alis (“pertaining to”) + noun suffix – itas |
| a. | femininity | ___________________________________________________________ |
| b. | originality | ___________________________________________________________ |
| c. | longitude | ___________________________________________________________ |
| d. | luminosity | ___________________________________________________________ |
| e. | acrimonious | ___________________________________________________________ |
| f. | spirituality | ___________________________________________________________ |
For Key to Exercises (Latin) , see Appendix I .


2.5: Magnetic Flux Density
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Magnetic flux density is a vector field which we identify using the symbol \({\bf B}\) and which has SI units of tesla (T). Before offering a formal definition, it is useful to consider the broader concept of the magnetic field .
Magnetic fields are an intrinsic property of some materials, most notably permanent magnets. The basic phenomenon is probably familiar, and is shown in Figure \(\PageIndex{1}\). A bar magnet has “poles” identified as “N” (“north”) and “S” (“south”). The N-end of one magnet attracts the S-end of another magnet but repels the N-end of the other magnet and so on. The existence of a vector field is apparent since the observed force acts at a distance and is asserted in a specific direction. In the case of a permanent magnet, the magnetic field arises from mechanisms occurring at the scale of the atoms and electrons comprising the material. These mechanisms require some additional explanation which we shall defer for now.
Figure \(\PageIndex{1}\): Evidence of a vector field from observations of the force perceived by the bar magnets on the right in the presence of the bar magnets on the left. ( CC BY 3.0 ; Y. Qin).Magnetic fields also appear in the presence of current. For example, a coil of wire bearing a current is found to influence permanent magnets (and vice versa) in the same way that permanent magnets affect each other. This is shown in Figure \(\PageIndex{2}\). From this, we infer that the underlying mechanism is the same – i.e., the vector field generated by a current-bearing coil is the same phenomenon as the vector field associated with a permanent magnet. Whatever the source, we are now interested in quantifying its behavior.
Figure \(\PageIndex{2}\): Evidence that current can also create a magnetic field. ( CC BY 4.0 ; Y. Qin).To begin, let us consider the effect of a magnetic field on a electrically-charged particle. First, imagine a region of free space with no electric or magnetic fields. Next, imagine that a charged particle appears. This particle will experience no force. Next, a magnetic field appears; perhaps this is due to a permanent magnet or a current in the vicinity. This situation is shown in Figure \(\PageIndex{2}\) (top). Still, no force is applied to the particle. In fact, nothing happens until the particle in set in motion. Figure \(\PageIndex{3}\) (bottom) shows an example. Suddenly, the particle perceives a force. We’ll get to the details about direction and magnitude in a moment, but the main idea is now evident. A magnetic field is something that applies a force to a charged particle in motion, distinct from (in fact, in addition to) the force associated with an electric field.
Figure \(\PageIndex{3}\): The force perceived by a charged particle that is (top) motionless and (bottom) moving with velocity \(\mathbf { v } = \hat { \mathbf { z } } v\), which is perpendicular to the plane of this document and toward the reader ( CC BY 4.0 ; Y. Qing).Now, it is worth noting that a single charged particle in motion is the simplest form of current. Remember also that motion is required for the magnetic field to influence the particle. Therefore, not only is current the source of the magnetic field, the magnetic field also exerts a force on current. Summarizing:
The magnetic field describes the force exerted on permanent magnets and currents in the presence of other permanent magnets and currents.
So, how can we quantify a magnetic field? The answer from classical physics involves another experimentally-derived equation that predicts force as a function of charge, velocity, and a vector field \({\bf B}\) representing the magnetic field. Here it is: The force applied to a particle bearing charge \(q\) is
\[\mathbf { F } = q \mathbf { v } \times \mathbf { B } \label{m0005_eFqvB} \]
where \({\bf v}\) is the velocity of the particle and “\(\times\)” denotes the cross product . The cross product of two vectors is in a direction perpendicular to each of the two vectors, so the force exerted by the magnetic field is perpendicular to both the direction of motion and the direction in which the magnetic field points.
The reader would be well-justified in wondering why the force exerted by the magnetic field should perpendicular to \({\bf B}\). For that matter, why should the force depend on \(\bf v\)? These are questions for which classical physics provides no obvious answers. Effective answers to these questions require concepts from quantum mechanics, where we find that the magnetic field is a manifestation of the fundamental and aptly-named electromagnetic force . The electromagnetic force also gives rises to the electric field, and it is only limited intuition, grounded in classical physics, that leads us to perceive the electric and magnetic fields as distinct phenomena. For our present purposes – and for most commonly-encountered engineering applications – we do not require these concepts. It is sufficient to accept this apparent strangeness as fact and proceed accordingly.
Dimensional analysis of \ref{m0005_eFqvB} reveals that \({\bf B}\) has units of (N\(\cdot\)s)/(C\(\cdot\)m). In SI, this combination of units is known as the tesla (T).
We refer to \({\bf B}\) as magnetic flux density , and therefore tesla is a unit of magnetic flux density. A fair question to ask at this point is: What makes this a flux density? The short answer is that this terminology is somewhat arbitrary, and in fact is not even uniformly accepted. In engineering electromagnetics, the preference for referring to \({\bf B}\) as a “flux density” is because we frequently find ourselves integrating \({\bf B}\) over a mathematical surface. Any quantity that is obtained by integration over a surface is referred to as “flux,” and so it becomes natural to think of \({\bf B}\) as a flux density; i.e., as flux per unit area. The SI unit for magnetic flux is the weber (Wb). Therefore, \({\bf B}\) may alternatively be described as having units of Wb/m\(^2\), and 1 Wb/m\(^2\) \(=\) 1 T.
Magnetic flux density (\({\bf B}\), T or Wb/m\(^2\)) is a description of the magnetic field that can be defined as the solution to Equation \ref{m0005_eFqvB}.
When describing magnetic fields, we occasionally refer to the concept of a field line , defined as follows:
A magnetic field line is the curve in space traced out by following the direction in which the magnetic field vector points.
This concept is illustrated in Figure \(\PageIndex{4}\) for a permanent bar magnet and Figure \(\PageIndex{5}\) for a current-bearing coil.
Figure \(\PageIndex{5}\): The magnetic field of a current-bearing coil, illustrating field lines. ( CC BY 4.0 ; Y. Qing).Magnetic field lines are remarkable for the following reason:
A magnetic field line always forms a closed loop.
This is true in a sense even for field lines which seem to form straight lines (for example, those along the axis of the bar magnet and the coil in Figures \(\PageIndex{4}\) and \(\PageIndex{5}\), since a field line that travels to infinity in one direction reemerges from infinity in the opposite direction.


11.1: What Is Evidence-Based Decision-Making?
By the end of this section, you should be able to:
- Describe evidence-based decision-making in public health.
- Describe the steps of evidence-based decision-making.
- Explain the importance of evidence-based decision-making in public health.
- Identify tools to support evidence-based public health decision-making.
Health care is designed to help enhance the quality of life for clients through preventative care, maximization of development, care of acute illness, and guidance toward death. Health care providers should use the most up-to-date information on care and treatment plans in these efforts. Evidence-based public health (EBPH) uses the best available current research and information to make decisions that encourage health promotion , disease prevention , and health maintenance . Comprehensively, “EBPH involves accessing the best available research to inform decisions, systematically using data and information systems, applying appropriate frameworks in program planning, engaging the community in assessment and decision-making activities, evaluating the program, and disseminating lessons learned to key stakeholders” (Ruebush, 2019, p. 1). Evidence-based decision-making (EBDM) is an essential element of EBPH. A key part of effective practice is applying evidence-based information.
EBDM is similar to evidence-based practice (EBP), yet each has its nuances for use in nursing. EBP uses the best available research, clinical experience, and client preferences to inform client-care interventions and evaluation. EBDM is the process of using the most recent research and clinical practice experience to make optimal decisions regarding a policy, practice, and/or program. Foundationally, EBDM extends from EBPH as they both consider the context of the community in conjunction with found evidence to identify and implement appropriate interventions. Additional considerations in the EBDM process include community partner buy-in, feasibility, cost-effectiveness, sustainability, health equity, and public sentiment.
Use of Evidence-Based Decision-Making
Public health is a sector of health care that seeks to protect and enhance the health of people and the communities in which they live, work, and play. Public health decisions and initiatives can have a broad impact, so it is important that they direct health care providers to use the most efficient and effective practices to promote the best possible results. Public health decision makers use EBDM to methodically determine which interventions work best in public health and then share this information with clients and other health care professionals.
The following are fundamental characteristics of EBDM that nurses and health care providers must consider (Cincinnati Children’s Hospital Medical Center [CCHMC], 2023):
- Using the best available peer-reviewed information to make decisions
- Using multiple forms of evidence
- Systematically utilizing data and information systems
- Employing program planning frameworks
- Optimizing community participation in decision-making and assessment, followed by a comprehensive evaluation
- Providing learned information to affected individuals and decision makers
- Implementing successful communication, scientific methods, common sense, and political concerns throughout each step
The National Collaborating Centre for Methods and Tools (NCCMT) has outlined seven steps in the evidence-based decision-making process in public health. Figure 11.2 breaks down these steps—define, search, appraise, synthesize, adapt, implement, and evaluate—to describe the process of EBDM.
Defining the Problem
The first step in the EBDM process is to clearly define the concern, the problem or question that needs to be addressed. Questions to consider in this step include:
- Who is the target group?
- Which problem or problems need to be solved?
- What is the anticipated plan to implement necessary changes?
The concern is generally formatted as an answerable PICOT question . A PICOT question frames the problem in terms of the affected population, the proposed intervention, the groups in the population that will be compared to determine the effectiveness of the intervention, the outcome being studied, and the time frame in which the study will take place. Table 11.1 presents the breakdown of a PICOT question.
| P | Population |
Outlines the client or client population affected by the problem and with whom the nurse will be in contact. Populations may be defined in multiple ways, some of which include the following:
|
| I | Intervention | Refers to the change or treatment that will be implemented for the outlined client (population). |
| C | Comparison | Outlines the reference groups for whom the population in question will be compared. This would be a comparison for the chosen intervention. |
| O | Outcome | The result that the project will be studying or evaluating. |
| T | Time | The time interval in which this project will take place, such as when and for how long the intervention will be in place and then compared to the outlined control group. |
Identifying each component of a PICOT question helps to clearly define the problem. This question then guides the literature search and the steps in EBDM in public health. As noted, the population may include individuals, communities, or a larger population group. The nurse must decide if the population will be further defined, such as by age, literacy level, or socioeconomic status. Interventions may involve a specific change or treatment, or they may test an approach to health not previously used or studied in this specific population with the outlined concern. The comparison may be a different intervention, often the one currently in practice, or the absence of the proposed intervention. Outcomes will contain measurable results or the aftermath of the implemented intervention. Time outlines how long the intervention will be in place and/or how long outcomes will be measured. Table 11.2 provides example PICOT questions as well as the breakdown of the elements for each question.
| Examples | Population | Intervention | Comparison | Outcome | Time |
|---|---|---|---|---|---|
| Do early intervention programs provided between 14 and 16 years of age prevent underage drinking among adolescents who live in rural areas within the United States? | Adolescents in rural areas within the United States | Early intervention programs | No early intervention programs | Prevent underage drinking | 14–16 years of age |
| For adults over age 60, does a daily 20-minute exercise regimen reduce the risk of hypertension compared with no daily exercise regimen over 3 years? | Adults over age 60 | 20-minute daily exercise regimen | No daily exercise regimen | Risk of hypertension | 3 years |
| Are women ages 18–25 years who use intrauterine devices (IUDs) for contraception at an increased risk for developing blood clots compared to women 18–25 years who use oral contraception over 5 years? | Women ages 18–25 years | IUD contraception | Oral Contraception | Risk for blood clot development | 5 years |
Searching the Literature
The next step in the process, searching , involves reviewing the literature to examine what research is available to address the defined concern and additional data points, which should consider the population in question. A clearly defined question guides nurses’ evidence search. Where to Find Evidence-Based Interventions will further discuss potential sources. Public health may utilize both qualitative and quantitative data or information as they both may apply to this subset of health care, and both may be used to help answer questions in public health. Quantitative research contains numbers and objective data to evaluate outcomes and determine results. Quantitative data are expressed by amounts in numerical terms. Often in public health, this is epidemiologic data. Qualitative research deals with nonnumerical data such as experiences, attitudes, and behaviors. Qualitative data are expressed in word form, cannot be quantified, and describe perspectives of individuals and populations. Another option for seeking information is a focus group. Focus groups are interviews conducted with small groups of participants who share similar traits or interests that will inform the current problem or issue in discussion. These groups are often used to gauge health beliefs, evaluate programs, and provide information fitting the needs assessment.
A community needs assessment is an appraisal that identifies a community’s strengths and resources. The needs assessment gives reviewers a quick overview of existing systems and policies and areas that need improvement or additional resources. Assessment, Analysis, and Diagnosis covers conducting a community needs assessment in more detail. Often a windshield survey is part of the community assessment. This is the process of observing the community while driving or walking through it to obtain a visual overview. Creating a Healthy Community discusses windshield surveys in more detail. An additional part of this needs assessment is identifying any possible community partners. Community partners are those individuals or organizations who are impacted by the project’s evaluations and outcomes and thus are interested in the process. While selecting search modalities, health care providers should consider all public health angles, such as issues in the community context, community and political actions and preferences, research, and public health resources. These link closely with the NCCMT model for evidence-based decision-making (see Where to Find Evidence-Based Interventions). Finally, public health nurses may also obtain information regarding a population’s morbidity and mortality rates through the National Vital Statistics System . Public health care providers may also utilize public health surveillance to obtain data. The four types of broad categories for public health surveillance are noninfectious health conditions, infectious diseases, both infectious and noninfectious diseases and health conditions, and risk factors and exposures (Centers for Disease Control and Prevention [CDC], 2023a).
While searching the literature, nurses must seek data that note the experiences and requirements of marginalized communities. Since research and scientific work are driven, and thus inhibited, by the perspectives and biases of those who conduct the work, there are notable communities and populations that lack accurate representation within studies, scientific theories, policies, and fact statements. To gather accurate information regarding these marginalized communities, nurses should utilize disaggregated data, or data that has been further broken down into subcategories, such as gender or race, to evaluate health inequities. Additionally, nurses must have a full understanding of the social determinants of health and how these apply to the root causes of inequitable health care access and availability. Ultimately, to identify disparities that may go otherwise unnoticed, data should be analyzed from an intersectional vantage point that recognizes the interdependence of different social identities such as gender, race, ethnicity, age, religious beliefs, developmental abilities and disabilities, and socioeconomic status.
Appraising the Literature
While a significant amount of published research may be available for any given concern, the studies may not be of equal quality. Critically appraising , or assessing each study for relevance and credibility, is necessary to ensure the information provided is meaningful, trustworthy, and relevant. Literature that is meaningful will be useful in some way and/or produce important information. Information is considered trustworthy based on its confirmability and the reviewer’s confidence in the believability of the information produced in the literature. Finally, relevance considers how pertinent the evidence is to the current problem and population. While there may be literature and evidence that provide valuable information, if the information is irrelevant to the topic in discussion or does not consider similar circumstances for the population, it may not be useful or applicable. This appraisal step should help nurses and other health care providers determine if the methods used in the selected studies or data points are strong enough to use in the problem-solving process. Once each source has been appraised for validity and then reviewed, the information can be synthesized. Where to Find Evidence-Based Interventions in this chapter will further discuss where to find evidence-based interventions, and Evaluating the Quality of the Evidence will discuss evaluating the quality of evidence.
In addition to appraising research articles themselves, all other forms of data should be appraised accordingly. Depending on the population, problem, and resources available, some sources may hold a greater weight based on the specific topic and community in question.
Synthesizing the Data
Synthesizing the data involves compiling the information to determine what the research says about the concern. The nurse synthesizing the articles and other data points should consider overlapping themes or messages from different sources. If the research offers conflicting messages, referring back to the appraisal step will be helpful in determining which may be more trustworthy or applicable to the current project. The research that the appraisal process determines to be of the highest quality should hold more weight in decisions. Additionally, in this step, health care providers should synthesize the information gathered from other data sources to identify common themes or attributes of the community or client.
Adapting the Information
The adapting step of this process involves determining if this synthesized information can apply to the client (which may be a single person, a family, a community, or a population). In population health, the client is often a community or a whole population, and therefore interventions must work broadly. Referring to the synthesizing step, the nurse should identify actionable steps as possible interventions. In the adapting stage, nurses should consider whether these interventions will be successful or relevant to the client in question and/or if the intervention will need adaptation to work efficiently. Components to consider are the identified problem, the identified intervention, the level of client (single person, family, community, or population), and any other affected individuals that need to be considered, such as organizations or partners in the process. An intervention that is successful in one community may not be successful in another community. Community and population attributes should be considered to determine applicability across clients. These should be considered and discussed during the dissemination phase of the project. Limitations or additional factors to consider should be discussed to help others determine if the intervention(s) can be applied to their specific population.
Implementing the Intervention
The implementation stage involves acting on the information and carrying out the determined plan after a possible intervention or action is identified and brainstorming has taken place regarding how this may need to be adapted to the client in question. In this step, public health nurses will identify actionable and tangible steps for the process. In the public health sector, these often include changes in practice, programs, or policies. This may mean revision of the previously designed practice, program, or policy or delivery of a new version of these components. Client characteristics are crucial at this step as they drive how interventions may be implemented.
Thinking back to the appraisal step, recall that interventions that seem optimal based on research may not be the best option for the current problem. For example, literature might state that frequent time away or vacation would benefit the mental health of teens and young adults. Yet this population may have limited financial means or transportation that make this intervention less feasible. While multiple pieces of evidence may support an intervention, a public health nurse can use their expertise to determine whether an intervention is appropriate for a specific population. If this is discussed in the adapt stage, it may be possible to alter aspects of an intervention to meet the needs of the local context.
Evaluating the Effectiveness of the Plan
Evaluation , the final step in this process, entails determining if the plan accomplished what was intended and, if not, what may need to be changed moving forward. The previously determined indicators are used as an objective measurement of success for the project. Once the effectiveness has been reviewed and evaluated, the team may then determine if they should continue with the intervention(s) as designed or adjust them based on the evaluation.
The NCCMT has created the video “Using Evidence in Public Health Decisions: Why It Matters” to emphasize why using evidence-informed decision-making is essential in public health.
Watch the video, and then respond to the following questions.
- How does EBDM impact financial decisions regarding implementation of health interventions?
- Discuss how EBDM can help build the relationship between health care providers and the public.
(See NCCMT, 2017.)
Additionally, the information should be disseminated for use by other health care providers or systems. An essential step in all health care research is sharing results to benefit the population as a whole. Sharing information within the nursing community increases the scope of knowledge within the field and helps to ensure all parties stay up-to-date with policies, practices, programs, and interventions. This may also optimize the cost and quality of care by sharing what has or has not worked in the past. This eliminates multiple steps of trial and error regarding the same topic.
Read the scenario, and then answer the questions that follow.
Recall from the beginning of this chapter that Amari and Milo have noticed an increased rate of anxiety in teens within their community and that the interventions they have used previously are not eliciting the same results. To efficiently identify possible interventions for this population, they know their best option is to use evidence-based practice strategies and that they must first draft a PICOT question as the foundation for their EBP project.
Amari and Milo develop the following PICOT question: Does daily exercise have an impact on anxiety rates in adolescents compared to those who do not engage in daily exercise over 3 months?
1. Which of the following components must be covered to be an effective PICOT question?
- Population, interest, cost, outcome, time
- Population, intervention, comparison, outcome, time
- Price, interest, comparison, overhead, time
- Price, intervention, company, outcome, time
2. In the PICOT question developed by Amari and Milo, which of the following is the proposed intervention?
- Anxiety rates
- Adolescents
- Daily exercise
- 3 months
Importance of Evidence-Based Decision-Making
The intent of health care is to ultimately improve client outcomes with the goal of providing the most effective care available. The EBDM process increases the objectivity of public health decision-making. Historically, health care treatments and skills relied on wisdom passed from one person to another in the form of anecdotes and demonstrations, which may be unreliable. This informal transmission of knowledge, skills, and treatments exemplifies a 19th-century technique that American surgeon William Stewart Halsted called “see one, do one, teach one” (Ayub, 2022). Following this philosophy, nurses should see a skill or technique being completed by another nurse, perform this skill or technique themselves, and then teach a less experienced nurse how to do the skill as needed. While this technique has been relatively effective historically, and while the nursing field as a whole is based on collaboration and knowledge sharing, the technique has flaws. If the original nurse did not perform the skill safely based on the most recent evidence, any nurses who learned the skill from the original nurse would follow the same unsafe pattern. For example, if the first nurse demonstrating insertion of a peripheral intravenous line chooses to rip the finger off their glove to touch the vein site after cleaning the identified site, each subsequent nurse may follow this unsafe process, increasing infection risks to all clients moving forward based on this inappropriate protocol. Similarly, the “see one, do one, teach one” technique relies on each nurse’s memory and the efficacy of each nurse who follows, leading to many opportunities for subjective error. Furthermore, this practice is more difficult to implement on a larger scale such as public health nursing where there is often not an opportunity to directly view the application of a skill.
EBP and EBDM are objective and concrete methods for finding relevant information and applying it to a particular problem. In public health, EBDM is used to ensure that interventions are supported by data and thus should be effective and that they reach the intended population (CCHMC, 2023). It also considers the available resources within the community. The EBDM process provides a compelling rationale for a course of action, whether that action is the continuation of an existing practice or the adoption of a new intervention. The process is thorough and can be replicated. According to NCCMT, evidence-based decision-making in public health should consider research, community health issues (with local context), community and political preference and actions, public health resources, and the public health expertise of decision makers (NCCMT, 2023a) (Table 11.3). Though there may be more steps involved in EBDM than in historic methods of teaching and decision-making, it enables the nurse to use informed and objective data to make the best and safest decision for the client (Erwin et al., 2020).
| Public Health Expertise | Sources of Evidence |
|---|---|
| Decision makers use their public health expertise and consider evidence from these sources: |
|
The video “NCCMT - URE - Evidence Informed Decision Making - A Guiding Framework for Public Health” presents an overview of the EIDM model. It examines the five overlapping ovals depicted in the model as types of evidence used to inform decision-making. The video uses the example of respiratory illness rates to show how two communities might use other sources of evidence to reach different evidence-informed decisions.
Watch the video, and then respond to the following questions.
- How might health inequities impact the research phase of the evidence-based decision-making process?
- Discuss how the unique sources of evidence discussed in the model overlap with one another and with public health expertise.
(See NCCMT, 2018.)
Tools to Support Evidence-Based Decision-Making
Multiple resources and tools are available to assist health care providers in using EBDM. To effectively use these tools and resources, it is necessary to have a strong foundational understanding of the specific client, from a single person up to a whole population. Though much of the information will be gathered from research, to align interventions, these tools must also connect to the designated population and the identified concern for them to prove valuable in the decision-making process. Some tools and resources are designed to support clinical decisions, while others are aimed at working through the EBDM process.
Clinical decision-making support tools are formatted as resources in which health care providers can quickly look up information on clinical practices, assessments, diagnostics, and treatments. One example is UpToDate , which focuses on point-of-care utilizing EBP to make recommendations (Wolters Kluwer, 2023b). This user-friendly, broadly accepted tool provides information for all subspecialties of internal medicine. Another available tool is Lexicomp , which houses detailed drug information in real time (Wolters Kluwer, 2023a). These tools can help health care providers at all levels make and discuss clinical decisions to determine what is currently in practice and help determine what may need to change.
Just as there are support tools available to facilitate clinical decisions, many tools are available to assist with the multistep process of EBDM. Some of these tools help determine a searchable question, while others help with the organization and categorization of identified research articles. Resources to help users define the problem focus on turning the identified concern into an answerable question and identifying key terms to guide an efficient search. Search tools are available to help users sift through data points and document results to track trends and highlighted usable factors. Tools for the appraisal step allow users to organize the data and appraise them accordingly. These tools have prompts and helpful formatting templates to keep appraised information organized. Synthesizing tools then help users pull out relevant information from their search and appraisal process. Adapting tools helps users evaluate the evidence for applicability and usability regarding their current concerns. Approaching the tactical aspect of the process, implementation tools help users plan for and carry out implementation based on their specific circumstance. Finally, evaluation tools and resources provide checklists of key aspects of EBDM and how to review the process that has taken place, starting with defining and moving through implementation (NCCMT, 2023b). To complete the process, there are tools to help with the reflection process of the evaluation phase. For example, McMaster University’s Health Evidence website has multiple tools specifically designed for this process in the public health sector.
McMaster University’s Health Evidence website offers tools for evidence-informed decision-making. Examples of tools include an EIDM checklist, a resource guide, a search tracker, and search strategies for developing a PICOT question.
Watch the video, and then answer the following questions.
- What are the three main methods for searching within Health Evidence?
- Health Evidence utilizes sources at which level of evidence to evaluate the effectives of public health interventions? Why is this evidence leveling important?
- What rating system is used in this database?
By utilizing these tools, nurses and other health care providers can make the complex process of EBDM more attainable by breaking these steps into manageable tasks.