<IP_ADDRESS>.1: Database Administrator
Database Administrator
A database administrator (DBA) is the person who manages the databases for an organization through the use of either application software and existing systems, or design, engineer, install, and maintain a brand new database. The DBA must have an extensive understanding of database queries, theories, server systems, and computing skills in order to work successfully for a company. Oftentimes, it may be a requirement that a Database Administrator has at least a bachelor’s or master’s degree in computer science in addition to certifications in database administration.
References
Database administrator. (2021, April 19). Retrieved from https://en.Wikipedia.org/wiki/Database_administrator


6.4: Accordions
Accordion widgets can come in single or multi-select formats, in which one or multiple panels can be opened at once, respectively. They are typically used to reduce the space that content occupies and to reduce scrolling. Accordions are made up of Accordion Headers and Accordion Panels. The accordion headers control the display of their associated accordion panel.
The WAI-ARIA roles, states, and properties used in an accordion
- aria-multiselectable =”(true | false)”
- role=”heading”
- role=”button”
- aria-controls=”[panel id]”
- tabindex=”0″
- role=”region”
- aria-hidden= “(true | false)”
- aria-expanded= “(true | false)”
The following JSFiddle presents a typical accordion widget. Review the JavaScript and HTML markup. Test the accordion presented under the Result tab with ChromeVox to understand how it functions without any accessibility features added. You can work in JSFiddle itself by clicking “Edit in JSFiddle”, copying the accessibility/WAI-ARIA code described below to fix the accessibility of the accordion before completing Activity 9 on the page that follows.
First, add the accordion to the landmarked regions by assigning
role="region"
to the opening

element when the accordion is initialized, adding the region role to the
init()
function.
Next, add the
aria-multiselectable
attribute to the

, which will be dynamically set to true or false based on plugin configuration settings. This lets a user know that more than one accordion panel can be opened when set to TRUE or only a single panel when set to FALSE. Refer to the
$(document).ready
block in the HTML, where the assignment takes place.
The semantics of the children of the

element, which was assigned
role="presentation"
, will also have their definition list semantics removed. Add the accordion semantics
role="heading"
to assign a heading role to the

elements. The
aria-level
attribute might be used to implement nested accordion panels, but for our purpose here a simplified version is sufficient.
Add a

inside the header (i.e.,
DT
) and define its
role
as a button. The button is given an
aria-controls
attribute to define which of the accordion panels it controls. By default the toggle state is set to false with
aria-expanded="false"
to be updated dynamically when the button is clicked or key pressed. Finally add
tabindex="0"
to the button (

) to make it keyboard focusable.
The tabindex will make the button focusable, but it will not make it clickable. The
.on()
jQuery function adds a click event to the button, but a keypress event must also be added. Adding
.on('keydown')
activates the
onKeyDown
function, defined below, so the accordion headers operate with both a mouse click and a keypress.
In the
togglePanel()
function, before
autoCollapse()
, add in the toggle to add and update the
aria-expanded
attribute for the panel headers, based on whether the associated panel is visible or not.
Within the
autoCollapse()
function, toggle
aria-expanded="false"
and
aria-hidden="true"
for all accordion tabs that are not the current one. This ensures only one panel is open at a time.
Finally, the accordion panel semantics are added, defining the

elements that had its semantics removed when
role="presentation"
was added to the parent

. Panels are given a generic
role="region"
to make the panel browsable in the landmarks list, set to be hidden by default with
aria-hidden="true"
so all panels are closed when the page loads. Further,
tabindex="0"
is also added to make the panels keyboard focusable so the content of the panel is read as the user navigates to them.
Adding Keyboard Operability
WAI-ARIA best practices defines all recommended accordion keyboard functionality, listed below. In our example, only the required keyboard events are included.
Keyboard Interaction for Accordions
-
Enter or Space:
- When focus is on the accordion header for a collapsed panel, expands the associated panel. If the implementation allows only one panel to be expanded, and if another panel is expanded, collapses that panel.
- When focus is on the accordion header for an expanded panel, collapses the panel if the implementation supports collapsing. Some implementations require one panel to be expanded at all times and allow only one panel to be expanded; so they do not support a collapse function.
- Down Arrow (Optional): If focus is on an accordion header, moves focus to the next accordion header. If focus is on the last accordion header, either does nothing or moves focus to the first accordion header.
- Up Arrow (Optional): If focus is on an accordion header, moves focus to the previous accordion header. If focus is on the first accordion header, either does nothing or moves focus to the last accordion header.
- Home (Optional): When focus is on an accordion header, moves focus to the first accordion header.
- End (Optional): When focus is on an accordion header, moves focus to the last accordion header.
- Ctrl+Page Down (Optional): If focus is inside an accordion panel or on an accordion header, moves focus to the next accordion header. If focus is in the last accordion header or panel, either does nothing or moves focus to the first accordion header.
- Ctrl+Page Up (Optional): If focus is inside an accordion panel, moves focus to the header for that panel. If focus is on an accordion header, moves focus to the previous accordion header. If focus is on the first accordion header, either does nothing or moves focus to the last accordion header.
Source: WAI-ARIA Accordion Design Patterns
The following
onKeyDown
function has been created to add keyboard operability to the header elements of the accordion, allowing both Space bar and Enter keys to operate the toggles (i.e., headers) that open and close panels, and the Arrow keys to move between the accordion headers. By default, users can navigate between headers, and between headers and panels using the Tab key.
Accessible Accordion in Action
Watch the following video to see how ChromeVox interacts with an accordion. The Tab key is used to navigate into the accordions, move between accordion headers, and move between accordion headers and panels. Arrow keys can also be used to move between accordion headers, but not from headers to an associated panel. Aim to have the accordion you update in the activity on the following page operate and announce like the one in the video.
Video: Accessible Accordions


16.3: Membranes, Surface Features, and Layers
Our exploration of more in-depth heart structures begins by examining the membrane that surrounds the heart, the prominent surface features of the heart, and the layers that form the wall of the heart. Each of these components plays its own unique role in terms of function.
Membranes
The membrane that directly surrounds the heart and defines the pericardial cavity is called the pericardium or pericardial sac . It also surrounds the “roots” of the major vessels, or the areas of closest proximity to the heart. The pericardium, which literally translates as “around the heart,” consists of two distinct sublayers: the sturdy outer fibrous pericardium and the inner serous pericardium. The fibrous pericardium is made of tough, dense connective tissue that protects the heart and maintains its position in the thorax. The more delicate serous pericardium consists of two layers: the parietal pericardium, which is fused to the fibrous pericardium, and an inner visceral pericardium, or epicardium , which is fused to the heart and is part of the heart wall. The pericardial cavity, filled with lubricating serous fluid, lies between the epicardium and the pericardium
In most organs within the body, visceral serous membranes such as the epicardium are microscopic. However, in the case of the heart, it is not a microscopic layer but rather a macroscopic layer, consisting of a simple squamous epithelium called a mesothelium , reinforced with loose, irregular, or areolar connective tissue that attaches to the pericardium. This mesothelium secretes the lubricating serous fluid that fills the pericardial cavity and reduces friction as the heart contracts. Figure \(\PageIndex{1}\) illustrates the pericardial membrane and the layers of the heart.
Surface Features of the Heart
Inside the pericardium, the surface features of the heart are visible, including the four chambers. There is a superficial leaf-like extension of the atria near the superior surface of the heart, one on each side, called an auricle —a name that means “ear like”—because its shape resembles the external ear of a human (Figure \(\PageIndex{2}\)). Auricles are relatively thin-walled structures that can fill with blood and empty into the atria or upper chambers of the heart. You may also hear them referred to as atrial appendages. Also prominent is a series of fat-filled grooves, each of which is known as a sulcus (plural = sulci), along the superior surfaces of the heart. Major coronary blood vessels are located in these sulci. The deep coronary sulcus is located between the atria and ventricles. Located between the left and right ventricles are two additional sulci that are not as deep as the coronary sulcus. The anterior interventricular sulcus is visible on the anterior surface of the heart, whereas the posterior interventricular sulcus is visible on the posterior surface of the heart. Figure \(\PageIndex{2}\)illustrates anterior and posterior views of the surface of the heart.


5: Polynomial and Rational Functions
-
- 5.1: Prelude to Polynomial and Rational Functions
- Digital photography has dramatically changed the nature of photography. No longer is an image etched in the emulsion on a roll of film. Instead, nearly every aspect of recording and manipulating images is now governed by mathematics. An image becomes a series of numbers, representing the characteristics of light striking an image sensor. When we open an image file, software on a camera or computer interprets the numbers and converts them to a visual image.
-
- 5.2: Quadratic Functions
- In this section, we will investigate quadratic functions, which frequently model problems involving area and projectile motion. Working with quadratic functions can be less complex than working with higher degree functions, so they provide a good opportunity for a detailed study of function behavior.
-
- 5.3: Power Functions and Polynomial Functions
- Suppose a certain species of bird thrives on a small island. The population can be estimated using a polynomial function. We can use this model to estimate the maximum bird population and when it will occur. We can also use this model to predict when the bird population will disappear from the island. In this section, we will examine functions that we can use to estimate and predict these types of changes.
-
- 5.4: Graphs of Polynomial Functions
- The revenue in millions of dollars for a fictional cable company can be modeled by the polynomial function From the model one may be interested in which intervals the revenue for the company increase or decreases? These questions, along with many others, can be answered by examining the graph of the polynomial function. We have already explored the local behavior of quadratics, a special case of polynomials. In this section we will explore the local behavior of polynomials in general.
-
- 5.5: Dividing Polynomials
- We are familiar with the long division algorithm for ordinary arithmetic. We begin by dividing into the digits of the dividend that have the greatest place value. We divide, multiply, subtract, include the digit in the next place value position,. Division of polynomials that contain more than one term has similarities to long division of whole numbers. We can write a polynomial dividend as the product of the divisor and the quotient added to the remainder.
-
- 5.6: Zeros of Polynomial Functions
- In the last section, we learned how to divide polynomials. We can now use polynomial division to evaluate polynomials using the Remainder Theorem. If the polynomial is divided by \(x–k\), the remainder may be found quickly by evaluating the polynomial function at \(k\), that is, \(f(k)\).
-
- 5.9: Modeling Using Variation
- A used-car company has just offered their best candidate, Nicole, a position in sales. The position offers 16% commission on her sales. Her earnings depend on the amount of her sales. For instance, if she sells a vehicle for $4,600, she will earn $736. She wants to evaluate the offer, but she is not sure how. In this section, we will look at relationships, such as this one, between earnings, sales, and commission rate.
Thumbnail: Identifying the behavior of the graph at an x-intercept by examining the multiplicity of the zero.
Contributors
-
Jay Abramson (Arizona State University) with contributing authors. Textbook content produced by OpenStax College is licensed under a Creative Commons Attribution License 4.0 license. Download for free at https://openstax.org/details/books/precalculus .


2.5: Standard Deviation (4 of 4)
Learning Objectives
- Use mean and standard deviation to describe a distribution.
Deciding Which Measurements to Use
We now have a choice between two measurements of center and spread. We can use the median with the interquartile range, or we can use the mean with the standard deviation. How do we decide which measurements to use?
Our next examples show that the shape of the distribution and the presence of outliers helps us answer this question.
Example
Homework Scores with an Outlier
Here are two summaries of the same set of homework scores earned by a student: a boxplot and an SD hatplot. Notice that the distribution of scores has an outlier. This student has mostly high homework scores with one score of 0. Here are some observations about the homework data.
- Five-number summary: low: 0 Q1: 82 Q2: 84.5 Q3: 89 high: 100
- Median is 84.5 and IQR is 7
- Mean = 81.8, SD = 17.6
The typical range of scores based on the first and third quartiles is 82 to 89.
The typical range of scores based on Mean ± SD is 64.2 to 99.4 (Here’s how we calculated this: 81.8 – 17.6 = 64.2, 81.8 + 17.6 = 99.4.)
Which is the better summary of the student’s performance on homework?
The typical range based on the mean and standard deviation is not a good summary of this student’s homework scores. Here we see that the outlier decreases the mean so that the mean is too low to be representative of this student’s typical performance. We also see that the outlier increases the standard deviation, which gives the impression of a wide variability in scores. This makes sense because the standard deviation measures the average deviation of the data from the mean. So a point that has a large deviation from the mean will increase the average of the deviations. In this example, a single score is responsible for giving the impression that the student’s typical homework scores are lower than they really are.
The typical range based on the first and third quartiles gives a better summary of this student’s performance on homework because the outlier does not affect the quartile marks.
Example
Skewed Incomes
In this example, we look at how skewness in a data set affects the standard deviation. The following histogram shows the personal income of a large sample of individuals drawn from U.S. census data in the year 2000. Notice that it is strongly skewed to the right. This type of skewness is often present in data sets of variables such as income.
Following are some summary statistics for this data:
- Mean = $24,000, SD = $27,500
- Median = $16,900, IQR = $28,000
The typical range based on the mean and standard deviation is not a good summary of the distribution of incomes. The small number of people with higher incomes increases the mean. The mean is too high to represent the large number of people making less than $20,000 a year. The small number of people with higher incomes also increase the standard deviation, so a small number of high incomes gives the misleading impression that typical incomes in the sample are higher than they really are.
Notice also that Mean ± SD gives an awkward range of typical values. The left endpoint is at −3,500 (Mean − SD = 24,000 − 27,500 = −3,500), but there are no negative values in this data set. This is another reason why it is better to use the IQR when measuring the spread of a skewed data set.
Let’s take a look at the same histogram, except this time we overlay a boxplot.
We see that the median represents the typical income of people in this sample better than the mean. The small number of people with higher incomes does not impact the median or the other quartile marks, so the first and third quartile marks give a range of incomes that more accurately represent typical incomes in the sample. Notice also that this range is always within the overall range of the data, so we will never have the problem that we encountered earlier with the standard deviation.
In a skewed distribution, the upper half and the lower half of the data have a different amount of spread, so no single number such as the standard deviation could describe the spread very well. We get a better understanding of how the values are distributed if we use the quartiles and the two extreme values in the five-number summary.
These examples illustrate some general guidelines for choosing numerical summaries:
- Use the mean and the standard deviation as measures of center and spread only for distributions that are reasonably symmetric with a central peak. When outliers are present, the mean and standard deviation are not a good choice.
- Use the five-number summary (which gives the median, IQR, and range) for all other cases.
Both of these examples also highlight another important principle: Always plot the data.
We need to use a graph to determine the shape of the distribution. By looking at the shape, we can determine which measures of center and spread best describe the data.
Let’s Summarize
- The average deviation from the mean (ADM) is a measurement of spread about the mean. More precisely, ADM measures the average distance of the data from the mean. In practice, ADM is not commonly used, but it helps us understand the standard deviation (SD).
- The standard deviation is a measure of spread. We use it as a measure of spread when we use the mean as a measure of center.
- The standard deviation is approximately the average distance of the data from the mean, so it is approximately equal to ADM.
- We can use the standard deviation to define a typical range of values about the mean. We mark the mean, then we mark 1 SD below the mean and 1 SD above the mean. This interval is centered at the mean and defines typical values about the mean. We often write this interval as Mean ± SD.
- We use technology to calculate the standard deviation.
- Like the mean, the standard deviation is strongly affected by outliers and skew in the data.
When choosing numerical summaries,
- Use the mean and the standard deviation as measures of center and spread only for distributions that are reasonably symmetric with a central peak. When outliers are present, the mean and standard deviation are not a good choice.
- Use the five-number summary (which gives the median, IQR, and range) for all other cases.
- Always plot the data. We need to use a graph to determine the shape of the distribution. By looking at the shape, we can determine which measures of center and spread best describe the data.
Contributors and Attributions
- Concepts in Statistics. Provided by : Open Learning Initiative. Located at : http://oli.cmu.edu . License : CC BY: Attribution


19.3: Introduction to Hiring for the Start-up Environment
What you’ll learn to do: Discuss how to hire for a start-up culture and environment
There are small businesses, and there are start-ups. Is there even a difference?
You hear the word “start-up” a lot in the technology field, and there’s a reason for that. A “start-up” is a small company that’s looking for a scalable and repeatable business model. Technology companies innovate a new product, and they’re looking to take it from something that’s been created in their garage to something that reach the far corners of the earth. They aren’t necessarily sure how to do that, but part of their business model is to show off that new technology and look for something or someone (like an “angel investor”) that can help them to that scalable, repeatable, next step.
A small business, on the other hand, is creating a business model that will work for the company from day one and continue to sustain them as they grow. There’s less innovation involved, and in fact, business models are often copied from other successful businesses in the same industry.
Contributors and Attributions
- Introduction to Hiring for the Start-up Environment. Authored by : Freedom Learning Group. Provided by : Lumen Learning. License : CC BY: Attribution
- Authored by : geralt. Provided by : Pixabay. Located at : pixabay.com/illustrations/arrows-growth-hacking-marketing-1229845/. License : CC0: No Rights Reserved . License Terms : Pixabay License


5.3: Example of Multiple Genes Affecting One Character
-
- Last updated
- Save as PDF
- Ying Liu
- City College of San Francisco
Cat Fur Genetics
Most aspects of the fur phenotypes of common cats can be explained by the action of just a few genes (Table 6-2). Other genes, not described here, may further modify these traits and account for the phenotypes seen in tabby cats and in more exotic breeds, such as Siamese.
For example, the X-linked Orange gene has two allelic forms. The O O allele produces orange fur, while the O B alleles produce non-orange (often black) fur. Note however, that because of X-chromosome inactivation the result is mosaicism in expression. In O O / O B female heterozygotes patches of black and orange are seen, which produces the tortoise shell pattern (Figure 6-13 A,B). This is a rare example of co-dominance since the phenotype of both alleles can be seen. Note that the cat in part A has short fur compared to the cat in part B; recessive alleles at an independent locus (L/l) produce long ( ll ) rather than short ( L_ ) fur.
Alleles of the dilute gene affect the intensity of pigmentation, regardless of whether that pigmentation is due to black or orange pigment. Part C shows a black cat with at least one dominant allele of dilute ( D_ ), in contrast to the cat in D, which is grey rather than black, because it has the dd genotype.
Epistasis is demonstrated by an allele of only one of the genes in Table \(\PageIndex{2}\). One dominant allele of white masking ( W ) prevents normal development of melanocytes (pigment producing cells). Therefore, cats with genotype ( W_ ) will have entirely white fur regardless of the genotype at the Orange or dilute loci (part E). Although this locus produces a white colour, W_ is not the same as albinism, which is a much rarer phenotype caused by mutations in other genes. Albino cats can be distinguished by having red eyes, while W_ cats have eyes that are not red.
Piebald spotting is the occurrence of patches of white fur. These patches vary in size due to many reasons, including genotype. Homozygous cats with genotype ss do not have any patches of white, while cats of genotype Ss and SS do have patches of white, and the homozygotes tend to have a larger proportion of white fur than heterozygotes (part F). The combination of piebald spotting and tortoise shell patterning produce a calico cat , which has separate patches of orange, black, and white fur.
| Trait | Phenotype | Genotype | Comments |
|---|---|---|---|
| fur length | short | LL or Ll | L is completely dominant |
| long | ll | ||
| all white fur (non-albino) | 100% white fur | WW or Ww | If the cat has red eyes it is albino, not W_ . W is epistatic to all other fur color genes; if cat is W_ , can’t infer genotypes for any other fur color genes. |
| ww | |||
| piebald spotting | > 50% white patches (but not 100%) | SS | S is incompletely dominant and shows variable expressivity |
| < 50% white patches | Ss | ||
| no white patches | ss | ||
| orange fur | all orange fur | X O X O or X O Y | O is X-linked |
| tortoise shell variegation | X O X B | ||
| no orange fur (often black) | X B X B or X B Y | ||
| dilute pigmentation | pigmentation is intense | Dd or dd | D is completely dominant |
| pigmentation is dilute (e.g. gray rather than black; cream rather than orange; light brown rather than brown) | dd | ||
| tabby | tabby pattern | AA or Aa | This is a simplification of the tabby phenotype, which involves multiple genes |
| solid coloration | aa | ||
| sex | female | XX | |
| male | XY |
References
- Adapted f rom Christensen (2000) Genetics 155:999-1004 )


1.1: Let’s Get Started- First Assignments
Introduction
Congratulations! You have now entered the world of making music with your voice. Whether you have sung for many years, or you just want to learn how to sing, this course is for you. The key to learning how to sing is to find your true voice, remove anything that stands in its way, and use your body and mind to create beautiful sound.
One common scenario for people wanting to learn how to sing better is the desire to sound like your favorite artist. We all enjoy listening to someone sing, and many wonder if they too could sound like that and maybe even become the next rising star. With the dawn of Youtube stars, shows like The Voice , and the easy access to an unlimited variety of music through devices such as smart phones, now it is easier than ever to put yourself out there for the world to hear. What if someone discovers me, and I get that recording contract and tour around the world?
Another common scenario for people interested in this course is simply curiosity about how to sing. Instead of the dream of being the next star, this student simply wants to learn how to actually sing. It doesn’t hurt that the course fulfills a SUNY General Elective, so why not learn this great skill in college?
This course is designed to bring the student back to the basics of singing, remove any obstacles the student has created mentally and physically, and receive core knowledge of how to sing properly with one’s true voice. There are many things a person can do to try to make his or her voice sound like someone else, and most times this is a contrived sound, destined to become difficult to produce due to tension. Instead, why not create sound with the real voice that follows that style of singing, and brings out one’s unique voice? This type of sound is not only sustainable over time, but allows the singer to explore several different styles of music, giving flexibility to his or her performance.
If you have never read music before and simply learn by ear, fear not. This course is also designed to allow the inexperienced singer to learn the material in different ways. There will be a brief introduction on how to read music, but all the material can also be learned by ear through the use of recordings.
Throughout the course, a variety of assessment methods will be used, giving the opportunity to consume the material from different styles of learning. There are written recorded lectures, written summaries, quizzes, discussions, vocal assessments in which the singer recorded him or herself singing for evaluation, and exams. The vocal assessments follow a pretest/posttest model. In other words, you are graded on mastery but mainly on improvement throughout the course. No matter where you start vocally, the main idea is to improve. By the end of the course, all will have the tools to look at any new music, and know how to sing it well.
First, I need to know where your starting point will be, so there will be a series of written questions, and vocal assessments just to judge where you are today vocally. So let’s begin!
What you will need for this course:
A solid connection to the Internet: If you are working on a quiz and your Internet times out, all work can be lost. Be sure when working on assessments that you have a strong connection.
A device to video record yourself for singing assessments: A smart phone is ideal for this requirement, but any device that can record and upload to the Internet will be sufficient. See system requirements for file type and size.
Access to a second device to play audio while recording: For some of the assessments, there will be a prerecorded track to play behind your singing. Smart phones have limited ability to play and record at the same time, so this can be any other device such as a computer, smart device, or even another phone.
About Yourself
Please answer the following questions in complete sentences:
1. What is your singing background?
2. What is your favorite style of singing?
3. If you had to pick a favorite singer, who would that be, and why?
4. What are your singing goals for this course?
5. On a scale of 1 to 7, 7 being the best, how would you rate your music reading ability?


7.1: Triads
- Triads are basic three-note chords built of thirds. They can be in root position, first inversion, or second inversion.
Harmony in Western music is based on triads. Triads are simple three-note chords built of thirds .
Triads in Root Position
Triads in Root Position
The chords in Figure 1 are written in root position, which is the most basic way to write a triad. In root position, the root, which is the note that names the chord, is the lowest note. The third of the chord is written a third higher than the root, and the fifth of the chord is written a fifth higher than the root (which is also a third higher than the third of the chord). So the simplest way to write a triad is as a stack of thirds, in root position.
The type of interval or chord - major, minor, diminished, etc., is not important when you are determining the position of the chord. To simplify things, all notes in the examples and exercises below are natural, but it would not change their position at all if some notes were sharp or flat. It would, however, change the name of the triad - see Naming Triads .
Write a triad in root position using each root given. If you need some staff paper for exercises you can print this PDF file .
Solution
First and Second Inversions
Any other chord that has the same-named notes as a root position chord is considered to be essentially the same chord in a different position. In other words, all chords that have only D naturals, F sharps, and A naturals, are considered D major chords.
But if you change the pitch or spelling of any note in the triad, you have changed the chord (see Naming Triads ). For example, if the F sharps are written as G flats, or if the A's are sharp instead of natural, you have a different chord, not an inversion of the same chord. If you add notes, you have also changed the name of the chord (see Beyond Triads ). You cannot call one chord the inversion of another if either one of them has a note that does not share a name (for example "F sharp" or "B natural") with a note in the other chord.
If the third of the chord is the lowest note, the chord is in first inversion. If the fifth of the chord is the lowest note, the chord is in second inversion. A chord in second inversion may also be called a six-four chord, because the intervals in it are a sixth and a fourth.
It does not matter how far the higher notes are from the lowest note, or how many of each note there are (at different octaves or on different instruments); all that matters is which note is lowest. (In fact, one of the notes may not even be written, only implied by the context of the chord in a piece of music. A practiced ear will tell you what the missing note is; we won't worry about that here.) To decide what position a chord is in, move the notes to make a stack of thirds and identify the root.
Rewrite each chord in root position, and name the original position of the chord.


9.9B: Muscles of the Wrist and Hand
Muscles in the forearm move the wrists, and hand movement is caused by both forearm and hand muscles.
- Outline the movements of the wrist and hand muscles
Key Points
- Movements of the wrist include abduction, adduction, extension, and flexion.
- Movements of the fingers and thumb include abduction, adduction, extension, and flexion.
- Rotation of the thumb and little finger allows for opposition.
- Muscles of the forearm that act on the wrist and hand are referred to as extrinsic muscles, or external to the hand.
- Muscles within the wrist and hand are referred to as intrinsic muscles.
Key Terms
- Palmaris Longus : A long muscle originating near the elbow and passing through into the wrist, attaching to the base of the hand.
- Flexor Digitorum Superficialis : A key muscle controlling wrist and finger flex.
- Flexor Carpi Ulnaris : A long muscle originating near the elbow and passing through into the wrist, attaching to one of the carpal bones in the wrist.
- Flexor Carpi Radialis : A long muscle originating near the elbow and passing through into the wrist, attaching to the base of the digits (fingers).
- Flexor Digitorum Profundus : A long muscle originating near the elbow and passing through into the wrist, flexing the wrist and the most distant regions of the fingers.
- Pronator Teres : A rectangular muscle that pronates the forearm.
- Flexor Pollicis Longus : A long, deep muscle responsible for flexing the thumb.
- Pronator quadratus : A square-shaped muscle located adjacent to the wrist.
Muscles associated with the wrist include those of the forearm and hand that move the wrist and digits. The wrist and hand exhibit a remarkable range of movement, key for grasping and interaction with objects. These muscles can generate highly variable force, from the strong grip required when lifting a heavy object to the delicate movements required to write.
Muscles and tendons of the forearm and hand: The extrinsic muscles of the forearm are responsible for movement of the wrist and fingers. Often providing the more forceful movements required.
Muscles of the forearm that act on the wrist and hand are referred to as extrinsic muscles, or external to the hand. Those located within the hand are referred to as intrinsic.
Muscles of the Forearm
As with the upper arm, the forearm is split into anterior and posterior compartment. Each contains many more muscles than described below due to the requirement for more complex movements in the wrist and hand.
Anterior
The anterior compartment of the forearm is split into superficial, intermediate, and deep layers. These muscles are generally responsible for flexing of the wrist and fingers and pronation of the forearm.
Superficial Layer
Three muscles are located in the superficial layer of the anterior compartment of the forearm.
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Flexor Carpi Ulnaris
: A long muscle originating near the elbow and passing through into the wrist.
- Attachments: Originates from the humerus and ulna and attaches to one of the carpal bones in the wrist.
- Actions: Flexion and adduction at the wrist.
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Palmaris Longus
: A long muscle originating near the elbow and passing through into the wrist.
- Attachments: Originates from the humerus and attaches to the base of the hand.
- Actions: Flexion at the wrist.
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Flexor Carpi Radialis
: A long muscle originating near the elbow and passing through into the wrist.
- Attachments: Originates from the humerus and attaches to the base of the digits.
- Actions: Flexion and abduction at the wrist.
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Pronator Teres
: A rectangular muscle.
- Attachments: The pronator teres has two origins, one on the proximal end of the humerus and one of the distal end of the ulna. It attaches to the mid region of the radius.
- Actions: Pronates the forearm.
Intermediate Layer
There is just one muscle in the intermediate layer of the anterior compartment of the forearm.
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Flexor Digitorum Superficialis
: Lying below the superficial region, the flexor digitorum superficialis is a key muscle controlling wrist and finger flex.
- Attachments: Originates from the humerus and the radius, splitting into four tendons at the wrist which travel through the carpal tunnel and attach to the fingers.
- Actions: Flexes fingers and wrist.
Deep Layer
There are three muscles in the deep layer of the anterior compartment of the forearm.
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Flexor Digitorum Profundus
: A long muscle originating near the elbow and passing through into the wrist, lying adjacent to the flexor pollicis longus.
- Attachments: Originates from the ulna, splitting into four tendons at the wrist which travel through the carpal tunnel and attach distally to the fingers.
- Actions: Flexes the wrist and the most distal regions of the fingers.
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Flexor Pollicis Longus
: A long muscle originating near the elbow and passing through into the wrist, lying adjacent to the flexor digitorum profundus.
- Attachments: Originates from the radius and attaches to the base of the thumb.
- Actions: Flexes the thumb.
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Pronator quadratus
: A square-shaped muscle located adjacent to the wrist.
- Attachments: Originates from the ulna and attaches to the radius.
- Actions: Pronates the forearm.
Posterior
The posterior compartment of the forearm is split into superficial and deep regions. The muscles are generally responsible for extension of the wrist and fingers.
Superficial Layer
The superficial layer of the posterior forearm contains seven muscles.
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Aconeus
: The aconeus is located in the superficial region of the forearm posterior compartment and is blended with the triceps brachii.
- Attachments: Originates from the humerus and attaches to the ulna.
- Actions: Moves the ulna during pronation and extends the forearm at the elbow.
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Brachioradialis
: The brachioradialis is located in the superficial region of the forearm posterior compartment.
- Attachments: Originates from the humerus and attaches to the distal end of the radius.
- Actions: Flexes the forearm at the elbow.
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Extensor Carpi Radialis Longus and Brevis
: A pair of muscles located on the side of the forearm, allowing them to control extension and abduction of the wrist.
- Attachments: Both originate from the humerus and attach to the base of the hand.
- Actions: Extend and abduct the wrist.
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Extensor Digitorum
: The extensor digitorum is the main extensor of the fingers.
- Attachments: Originates from the humerus, splitting into four tendons at the wrist which travel through the carpal tunnel and attach to the digits.
- Actions: Extends fingers.
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Extensor Digiti Minimi
: Originates from the extensor digitorum. In some people, these muscles cannot be individually defined.
- Attachments: Originates from the humerus and attaches to the little finger.
- Actions: Extends the little finger, and contributes to extension at the wrist.
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Extensor Carpi Ulnaris
: Located on the other side of the forearm to the extensor carpi radialis longus and brevis, it performs a similar role.
- Attachments: Originates from the humerus and attaches to the base of the hand.
- Actions: Extension and adduction of wrist.
Deep Layer
There are four muscles in the deep layer of the posterior compartment of the forearm.
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Supinator
: The supinator is located in the deep region of the forearm posterior compartment.
- Attachments: The supinator has two heads: one originates from the humerus, the other from the ulna. Together they attach to the radius.
- Actions: Supinates the forearm.
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Abductor Pollicis Longus
: The abductor pollicis longus is situated immediately distal to the supinator muscle.
- Attachments: Originates from the radius and ulna attaching to the base of the thumb.
- Actions: Abducts the thumb.
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Extensor Pollicis Brevis
: The extensor pollicis brevis is located below the abductor pollicis longus.
- Attachments: Originates from radius and attaches to the base of the thumb.
- Actions: Extends the thumb.
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Extensor Indicis Proprius
: This muscle allows the index finger to be independent of the other fingers during extension.
- Attachments: Originates from the ulna and attaches to the index finger.
- Actions: Extends the index finger.
Muscles of the Hand
The extrinsic muscles of the hand are responsible for the larger scale, stronger movements of the wrist and hand. The intrinsic muscles produce finer, more controlled movements and play important roles in maintaining grip.
Thenar Muscles
Muscles of the hand
The thenar muscles are three short muscles located at the base of the thumb and responsible for its fine movement.
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Opponens Pollicis
: The opponens pollicis is the largest and deepest-lying of the thenar muscles.
- Attachments: Originates from the wrist and attaches to the thumb.
- Actions: Rotates the thumb towards the palm, producing opposition and improving grip.
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Abductor Pollicis Brevis
: Located anteriorly to the opponens pollicis and proximal to the flexor pollicis brevis.
- Attachments: Originates from the wrist and attaches to the thumb.
- Actions: Abducts the thumb.
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Flexor Pollicis Brevis
: The smallest and most distal of the thenar muscles.
- Attachments: Originates from the wrist and attaches to the thumb.
- Actions: Flexes the thumb.
Hypothenar Muscles
The hypothenar muscles are located at the base of the little finger. Their naming, function, and organization are similar to those of the thenar muscles.
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Opponens Digiti Minimi
: The opponens digit minimi is the deepest-lying of the hypothenar muscles.
- Attachments: Originates from the wrist and attaches to the little finger.
- Actions: Rotates little finger towards the palm, producing opposition and improving grip.
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Abductor Digiti Minimi
: The most superficial of the hypothenar muscles.
- Attachments: Originates from the wrist and attaches to the little finger.
- Actions: Abducts the little finger.
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Flexor Digiti Minimi Brevis
: Located laterally to the digiti minimi.
- Attachments: Originates from the wrist and attaches to the little finger.
- Actions: Flexes little finger.
Lumbricals
These are four lumbricals in the hand, each associated with an individual finger.
- Attachments: Originates from a tendon of attached to the flexor digitorum profundus of the forearm, each attaching to an individual finger
- Actions: Flexes and extends the fingers.
Interossei
The interossei muscles are located between the fingers; they can be split into two groups.
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Dorsal
Interossei
: Located superficially on the dorsal side of the hand, there are four dorsal interossei muscles.
- Attachments: Originates from the base of the finger, each attaching after the first finger joint.
- Actions: Abducts the fingers.
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Palmar Interossei
: Located on the anterior side of the hand, there are three palmar interossei, with the index finger controlled by the extensor indicis proprius.
- Attachments: Originates from the base of the finger, each attaching after the first finger joint.
- Actions: Adducts the fingers.
Other Muscles
One other muscle in the hand is not easily grouped with the above categories.
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Palmaris Brevis
: The palmaris brevis is a small superficial muscle found in the palm.
- Attachments: Originates from the fascia of the palm and attaches to the dermis.
- Actions: Wrinkles the skin and deepens the curvature of the palm improving grip.


11.5: Key Words and Terms
| 64 codons | genetic code | ribonucleoprotein |
| adapter molecules | initiation | ribosome |
| amino terminus | initiation complex | small ribosomal subunit |
| aminoacyl tRNA | initiation factors | start codon |
| aminoacyl tRNA synthase | large ribosomal subunit | termination |
| anticodon | meaningful codons | termination factor |
| AUG | mRNA, tRNA | translocation |
| bacterial bound ribosomes | nascent chains | triplets |
| Carboxyl-terminus | ochre, amber, opal | tRNA v. tRNAaa |
| colinearity | peptide linkage | UAG, UUA, UGA |
| comma-less genetic code | peptidyl transferase | universal genetic code |
| degenerate genetic code | polypeptide | UUU |
| elongation | polysome | Wobble Hypothesis |
| free v. bound ribosomes | reading phase |


Chapter 8: The Cost of Business – Gender Dynamics of Media Labor in Afghanistan
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On September 11, 2001, Afghanistan’s media sphere was one of the sparsest in the world. Few newspapers had survived the previous half-decade of Taliban rule, during which the nation devolved into a “country without news or pictures,” according to Reporters Without Borders.¹ A single radio station, Radio Sharia, was in operation—the lone remnant of a bygone Soviet era marked by relatively sophisticated, if centrally controlled, broadcasting practices. According to the architects of the American-led invasion that would ultimately overthrow the Taliban regime, this lack of media was not only a symptom of totalitarianism but also a cause.
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8.1: Introduction
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Overview of the chapter's aims: to understand the specific gender dynamics that have emerged in Western-funded Afghan media production, comparing the nonprofit and commercial sectors, and to identify the instability affecting workers in both sectors, especially women workers.
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8.2: Rightful Suspicions
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The Western emphasis on media assistance as a form of women's liberation in Afghanistan post-9/11; the "top-down" nature of that gender rights discourse that assumes Afghan women lack the agency to empower themselves and asserts a neoliberal, individualist ideal of women's empowerment.
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8.3: Case by Case – Women in For-Profit TV
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The youth-dominated Afghan for-profit mediasphere, and some of the factors that bring women to producerial positions in this sphere but keep them from retaining stable positions there.
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8.4: The Noncommercial Sector
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Examining the role of and the challenges faced by women in Afghanistan's noncommercial, Western-funded media sector, focusing on the case studies of Zakia Zaki and Farida Nekzad.
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8.5: Conclusion
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Considering the ways in which the American-funded media system in Afghanistan has created new opportunities for women, while at the same time creating additional precarity for women working in media.
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8.6: Notes
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26.3: Electrolyte Balance
Learning Objectives
- List the role of the six most important electrolytes in the body
- Name the disorders associated with abnormally high and low levels of the six electrolytes
- Identify the predominant extracellular anion
- Describe the role of aldosterone on the level of water in the body
The body contains a large variety of ions, or electrolytes, which perform a variety of functions. Some ions assist in the transmission of electrical impulses along cell membranes in neurons and muscles. Other ions help to stabilize protein structures in enzymes. Still others aid in releasing hormones from endocrine glands. All of the ions in plasma contribute to the osmotic balance that controls the movement of water between cells and their environment.
Electrolytes in living systems include sodium, potassium, chloride, bicarbonate, calcium, phosphate, magnesium, copper, zinc, iron, manganese, molybdenum, copper, and chromium. In terms of body functioning, six electrolytes are most important: sodium, potassium, chloride, bicarbonate, calcium, and phosphate.
Roles of Electrolytes
These six ions aid in nerve excitability, endocrine secretion, membrane permeability, buffering body fluids, and controlling the movement of fluids between compartments. These ions enter the body through the digestive tract. More than 90 percent of the calcium and phosphate that enters the body is incorporated into bones and teeth, with bone serving as a mineral reserve for these ions. In the event that calcium and phosphate are needed for other functions, bone tissue can be broken down to supply the blood and other tissues with these minerals. Phosphate is a normal constituent of nucleic acids; hence, blood levels of phosphate will increase whenever nucleic acids are broken down.
Excretion of ions occurs mainly through the kidneys, with lesser amounts lost in sweat and in feces. Excessive sweating may cause a significant loss, especially of sodium and chloride. Severe vomiting or diarrhea will cause a loss of chloride and bicarbonate ions. Adjustments in respiratory and renal functions allow the body to regulate the levels of these ions in the ECF.
Table \(\PageIndex{1}\) lists the reference values for blood plasma, cerebrospinal fluid (CSF), and urine for the six ions addressed in this section. In a clinical setting, sodium, potassium, and chloride are typically analyzed in a routine urine sample. In contrast, calcium and phosphate analysis requires a collection of urine across a 24-hour period, because the output of these ions can vary considerably over the course of a day. Urine values reflect the rates of excretion of these ions. Bicarbonate is the one ion that is not normally excreted in urine; instead, it is conserved by the kidneys for use in the body’s buffering systems.
| Name | Chemical symbol | Plasma | CSF | Urine |
|---|---|---|---|---|
| Sodium | Na + | 136.00–146.00 (mM) | 138.00–150.00 (mM) | 40.00–220.00 (mM) |
| Potassium | K + | 3.50–5.00 (mM) | 0.35–3.5 (mM) | 25.00–125.00 (mM) |
| Chloride | Cl - | 98.00–107.00 (mM) | 118.00–132.00 (mM) | 110.00–250.00 (mM) |
| Bicarbonate | HCO 3 - | 22.00–29.00 (mM) | ------ | ------ |
| Calcium | Ca ++ | 2.15–2.55 (mmol/day) | ------ | Up to 7.49 (mmol/day) |
| Phosphate | HPO 2 − 4 | 0.81–1.45 (mmol/day) | ------ | 12.90–42.00 (mmol/day) |
Sodium
Sodium is the major cation of the extracellular fluid. It is responsible for one-half of the osmotic pressure gradient that exists between the interior of cells and their surrounding environment. People eating a typical Western diet, which is very high in NaCl, routinely take in 130 to 160 mmol/day of sodium, but humans require only 1 to 2 mmol/day. This excess sodium appears to be a major factor in hypertension (high blood pressure) in some people. Excretion of sodium is accomplished primarily by the kidneys. Sodium is freely filtered through the glomerular capillaries of the kidneys, and although much of the filtered sodium is reabsorbed in the proximal convoluted tubule, some remains in the filtrate and urine, and is normally excreted.
Hyponatremia is a lower-than-normal concentration of sodium, usually associated with excess water accumulation in the body, which dilutes the sodium. An absolute loss of sodium may be due to a decreased intake of the ion coupled with its continual excretion in the urine. An abnormal loss of sodium from the body can result from several conditions, including excessive sweating, vomiting, or diarrhea; the use of diuretics; excessive production of urine, which can occur in diabetes; and acidosis, either metabolic acidosis or diabetic ketoacidosis.
A relative decrease in blood sodium can occur because of an imbalance of sodium in one of the body’s other fluid compartments, like IF, or from a dilution of sodium due to water retention related to edema or congestive heart failure. At the cellular level, hyponatremia results in increased entry of water into cells by osmosis, because the concentration of solutes within the cell exceeds the concentration of solutes in the now-diluted ECF. The excess water causes swelling of the cells; the swelling of red blood cells—decreasing their oxygen-carrying efficiency and making them potentially too large to fit through capillaries—along with the swelling of neurons in the brain can result in brain damage or even death.
Hypernatremia is an abnormal increase of blood sodium. It can result from water loss from the blood, resulting in the hemoconcentration of all blood constituents. Hormonal imbalances involving ADH and aldosterone may also result in higher-than-normal sodium values.
Potassium
Potassium is the major intracellular cation. It helps establish the resting membrane potential in neurons and muscle fibers after membrane depolarization and action potentials. In contrast to sodium, potassium has very little effect on osmotic pressure. The low levels of potassium in blood and CSF are due to the sodium-potassium pumps in cell membranes, which maintain the normal potassium concentration gradients between the ICF and ECF. The recommendation for daily intake/consumption of potassium is 4700 mg. Potassium is excreted, both actively and passively, through the renal tubules, especially the distal convoluted tubule and collecting ducts. Potassium participates in the exchange with sodium in the renal tubules under the influence of aldosterone, which also relies on basolateral sodium-potassium pumps.
Hypokalemia is an abnormally low potassium blood level. Similar to the situation with hyponatremia, hypokalemia can occur because of either an absolute reduction of potassium in the body or a relative reduction of potassium in the blood due to the redistribution of potassium. An absolute loss of potassium can arise from decreased intake, frequently related to starvation. It can also come about from vomiting, diarrhea, or alkalosis.
Some insulin-dependent diabetic patients experience a relative reduction of potassium in the blood from the redistribution of potassium. When insulin is administered and glucose is taken up by cells, potassium passes through the cell membrane along with glucose, decreasing the amount of potassium in the blood and IF, which can cause hyperpolarization of the cell membranes of neurons, reducing their responses to stimuli.
Hyperkalemia , an elevated potassium blood level, also can impair the function of skeletal muscles, the nervous system, and the heart. Hyperkalemia can result from increased dietary intake of potassium. In such a situation, potassium from the blood ends up in the ECF in abnormally high concentrations. This can result in a partial depolarization (excitation) of the plasma membrane of skeletal muscle fibers, neurons, and cardiac cells of the heart, and can also lead to an inability of cells to repolarize. For the heart, this means that it won’t relax after a contraction, and will effectively “seize” and stop pumping blood, which is fatal within minutes. Because of such effects on the nervous system, a person with hyperkalemia may also exhibit mental confusion, numbness, and weakened respiratory muscles.
Chloride
Chloride is the predominant extracellular anion. Chloride is a major contributor to the osmotic pressure gradient between the ICF and ECF, and plays an important role in maintaining proper hydration. Chloride functions to balance cations in the ECF, maintaining the electrical neutrality of this fluid. The paths of secretion and reabsorption of chloride ions in the renal system follow the paths of sodium ions.
Hypochloremia , or lower-than-normal blood chloride levels, can occur because of defective renal tubular absorption. Vomiting, diarrhea, and metabolic acidosis can also lead to hypochloremia. Hyperchloremia , or higher-than-normal blood chloride levels, can occur due to dehydration, excessive intake of dietary salt (NaCl) or swallowing of sea water, aspirin intoxication, congestive heart failure, and the hereditary, chronic lung disease, cystic fibrosis. In people who have cystic fibrosis, chloride levels in sweat are two to five times those of normal levels, and analysis of sweat is often used in the diagnosis of the disease.
Watch this video to see an explanation of the effect of seawater on humans. What effect does drinking seawater have on the body?
Bicarbonate
Bicarbonate is the second most abundant anion in the blood. Its principal function is to maintain your body’s acid-base balance by being part of buffer systems. This role will be discussed in a different section.
Bicarbonate ions result from a chemical reaction that starts with carbon dioxide (CO 2 ) and water, two molecules that are produced at the end of aerobic metabolism. Only a small amount of CO 2 can be dissolved in body fluids. Thus, over 90 percent of the CO 2 is converted into bicarbonate ions, HCO 3 – , through the following reactions:
\[CO_2 + H_2O \rightleftharpoons H_2CO_3 \rightleftharpoons H_2CO_3^- + H^+\]
The bidirectional arrows indicate that the reactions can go in either direction, depending on the concentrations of the reactants and products. Carbon dioxide is produced in large amounts in tissues that have a high metabolic rate. Carbon dioxide is converted into bicarbonate in the cytoplasm of red blood cells through the action of an enzyme called carbonic anhydrase. Bicarbonate is transported in the blood. Once in the lungs, the reactions reverse direction, and CO 2 is regenerated from bicarbonate to be exhaled as metabolic waste.
Calcium
About two pounds of calcium in your body are bound up in bone, which provides hardness to the bone and serves as a mineral reserve for calcium and its salts for the rest of the tissues. Teeth also have a high concentration of calcium within them. A little more than one-half of blood calcium is bound to proteins, leaving the rest in its ionized form. Calcium ions, Ca 2+ , are necessary for muscle contraction, enzyme activity, and blood coagulation. In addition, calcium helps to stabilize cell membranes and is essential for the release of neurotransmitters from neurons and of hormones from endocrine glands.
Calcium is absorbed through the intestines under the influence of activated vitamin D. A deficiency of vitamin D leads to a decrease in absorbed calcium and, eventually, a depletion of calcium stores from the skeletal system, potentially leading to rickets in children and osteomalacia in adults, contributing to osteoporosis.
Hypocalcemia , or abnormally low calcium blood levels, is seen in hypoparathyroidism, which may follow the removal of the thyroid gland, because the four nodules of the parathyroid gland are embedded in it. Hypercalcemia , or abnormally high calcium blood levels, is seen in primary hyperparathyroidism. Some malignancies may also result in hypercalcemia.
Phosphate
Phosphate is present in the body in three ionic forms: H 2 PO 4 , HPO 4 2- and PO 4 3- .The most common form is HPO 4 2- Bone and teeth bind up 85 percent of the body’s phosphate as part of calcium-phosphate salts. Phosphate is found in phospholipids, such as those that make up the cell membrane, and in ATP, nucleotides, and buffers.
Hypophosphatemia , or abnormally low phosphate blood levels, occurs with heavy use of antacids, during alcohol withdrawal, and during malnourishment. In the face of phosphate depletion, the kidneys usually conserve phosphate, but during starvation, this conservation is impaired greatly. Hyperphosphatemia , or abnormally increased levels of phosphates in the blood, occurs if there is decreased renal function or in cases of acute lymphocytic leukemia. Additionally, because phosphate is a major constituent of the ICF, any significant destruction of cells can result in dumping of phosphate into the ECF.
Regulation of Sodium and Potassium
Sodium is reabsorbed from the renal filtrate, and potassium is excreted into the filtrate in the renal collecting tubule. The control of this exchange is governed principally by two hormones—aldosterone and angiotensin II.
Aldosterone
Recall that aldosterone increases the excretion of potassium and the reabsorption of sodium in the distal tubule. Aldosterone is released if blood levels of potassium increase, if blood levels of sodium severely decrease, or if blood pressure decreases. Its net effect is to conserve and increase water levels in the plasma by reducing the excretion of sodium, and thus water, from the kidneys. In a negative feedback loop, increased osmolality of the ECF (which follows aldosterone-stimulated sodium absorption) inhibits the release of the hormone (Figure \(\PageIndex{1}\)).
Angiotensin II
Angiotensin II causes vasoconstriction and an increase in systemic blood pressure. This action increases the glomerular filtration rate, resulting in more material filtered out of the glomerular capillaries and into Bowman’s capsule. Angiotensin II also signals an increase in the release of aldosterone from the adrenal cortex.
In the distal convoluted tubules and collecting ducts of the kidneys, aldosterone stimulates the synthesis and activation of the sodium-potassium pump (Figure \(\PageIndex{2}\)). Sodium passes from the filtrate, into and through the cells of the tubules and ducts, into the ECF and then into capillaries. Water follows the sodium due to osmosis. Thus, aldosterone causes an increase in blood sodium levels and blood volume. Aldosterone’s effect on potassium is the reverse of that of sodium; under its influence, excess potassium is pumped into the renal filtrate for excretion from the body.
Regulation of Calcium and Phosphate
Calcium and phosphate are both regulated through the actions of three hormones: parathyroid hormone (PTH), dihydroxyvitamin D (calcitriol), and calcitonin. All three are released or synthesized in response to the blood levels of calcium.
PTH is released from the parathyroid gland in response to a decrease in the concentration of blood calcium. The hormone activates osteoclasts to break down bone matrix and release inorganic calcium-phosphate salts. PTH also increases the gastrointestinal absorption of dietary calcium by converting vitamin D into dihydroxyvitamin D (calcitriol), an active form of vitamin D that intestinal epithelial cells require to absorb calcium.
PTH raises blood calcium levels by inhibiting the loss of calcium through the kidneys. PTH also increases the loss of phosphate through the kidneys.
Calcitonin is released from the thyroid gland in response to elevated blood levels of calcium. The hormone increases the activity of osteoblasts, which remove calcium from the blood and incorporate calcium into the bony matrix.
Chapter Review
Electrolytes serve various purposes, such as helping to conduct electrical impulses along cell membranes in neurons and muscles, stabilizing enzyme structures, and releasing hormones from endocrine glands. The ions in plasma also contribute to the osmotic balance that controls the movement of water between cells and their environment. Imbalances of these ions can result in various problems in the body, and their concentrations are tightly regulated. Aldosterone and angiotensin II control the exchange of sodium and potassium between the renal filtrate and the renal collecting tubule. Calcium and phosphate are regulated by PTH, calcitrol, and calcitonin.
Interactive Link Questions
Q. Watch this video to see an explanation of the effect of seawater on humans. What effect does drinking seawater have on the body?
Answer: Drinking seawater dehydrates the body as the body must pass sodium through the kidneys, and water follows.
Review Questions
Q. Bone serves as a mineral reserve for which two ions?
A. sodium and potassium
B. calcium and phosphate
C. chloride and bicarbonate
D. calcium and bicarbonate
Answer: B
Q. Electrolytes are lost mostly through ________.
A. renal function
B. sweating
C. feces
D. respiration
Answer: A
Q. The major cation in extracellular fluid is ________.
A. sodium
B. potassium
C. chloride
D. bicarbonate
Answer: A
Q. The major cation in intracellular fluid is ________.
A. sodium
B. potassium
C. chloride
D. bicarbonate
Answer: B
Q. The major anion in extracellular fluid is ________.
A. sodium
B. potassium
C. chloride
D. bicarbonate
Answer: C
Q. Most of the body’s calcium is found in ________.
A. teeth
B. bone
C. plasma
D. extracellular fluids
Answer: B
Q. Abnormally increased blood levels of sodium are termed ________.
A. hyperkalemia
B. hyperchloremia
C. hypernatremia
D. hypercalcemia
Answer: C
Q. The ion with the lowest blood level is ________.
A. sodium
B. potassium
C. chloride
D. bicarbonate
Answer: B
Q. Which two ions are most affected by aldosterone?
A. sodium and potassium
B. chloride and bicarbonate
C. calcium and phosphate
D. sodium and phosphate
Answer: A
Critical Thinking Questions
Q. Explain how the CO 2 generated by cells and exhaled in the lungs is carried as bicarbonate in the blood.
A. Very little of the carbon dioxide in the blood is carried dissolved in the plasma. It is transformed into carbonic acid and then into bicarbonate in order to mix in plasma for transportation to the lungs, where it reverts back to its gaseous form.
Q. How can one have an imbalance in a substance, but not actually have elevated or deficient levels of that substance in the body?
A. Without having an absolute excess or deficiency of a substance, one can have too much or too little of that substance in a given compartment. Such a relative increase or decrease is due to a redistribution of water or the ion in the body’s compartments. This may be due to the loss of water in the blood, leading to a hemoconcentration or dilution of the ion in tissues due to edema.
Glossary
- dihydroxyvitamin D
- active form of vitamin D required by the intestinal epithelial cells for the absorption of calcium
- hypercalcemia
- abnormally increased blood levels of calcium
- hyperchloremia
- higher-than-normal blood chloride levels
- hyperkalemia
- higher-than-normal blood potassium levels
- hypernatremia
- abnormal increase in blood sodium levels
- hyperphosphatemia
- abnormally increased blood phosphate levels
- hypocalcemia
- abnormally low blood levels of calcium
- hypochloremia
- lower-than-normal blood chloride levels
- hypokalemia
- abnormally decreased blood levels of potassium
- hyponatremia
- lower-than-normal levels of sodium in the blood
- hypophosphatemia
- abnormally low blood phosphate levels


That expanding understanding of themselves and others develops with age. Here is a table of social and emotional milestones that children typically experience during early childhood.
Table \(\PageIndex{1}\): Social and Emotional Milestones (
Developmental Milestones
by the
CDC
is in the public domain)
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Typical Age
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What Most Children Do by This Age
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3 years
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Copies adults and friends
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Shows affection for friends without prompting
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Takes turns in games
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Shows concern for a crying friend
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Dresses and undresses self
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Understands the idea of “mine” and “his” or “hers”
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Shows a wide range of emotions
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Separates easily from mom and dad
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May get upset with major changes in routine
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4 years
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Enjoys doing new things
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Is more and more creative with make-believe play
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Would rather play with other children than by self
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Cooperates with other children
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Plays “mom” or “dad”
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Often can’t tell what’s real and what’s make-believe
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Talks about what she likes and what she is interested in
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5 years
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Wants to please friends
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Wants to be like friends
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More likely to agree with rules
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Likes to sing, dance, and act
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Is aware of gender
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Can tell what’s real and what’s make-believe
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Shows more independence
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Is sometimes demanding and sometimes very cooperative
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Many things influence how children develop those milestones as how they view themselves and how they interact with those around them changes. Let’s look more at these.


5.3: How not to divide with 3 parties
When first approaching the question of 3-party fair division, it is very tempting to propose this method: Randomly designate one participant to be the divider, and designate the rest choosers. Proceed as follows:
1) Have the divider divide the item into 3 pieces
2) Have the first chooser select any of the three pieces they feel is worth a fair share
3) Have the second chooser select either of the remaining pieces
4) The divider gets the piece left.
Suppose we have three people splitting a cake. We can immediately see that the divider will receive a fair share as long as they cut the cake fairly at the beginning. The first chooser certainly will also receive a fair share. What about the second chooser? Suppose each person values the three pieces like this:
\(\begin{array}{|l|l|l|l|}
\hline & \textbf { Piece 1 } & \textbf { Piece 2 } & \textbf { Piece 3 } \\
\hline \textbf { Chooser 1 } & 40 \% & 30 \% & 30 \% \\
\hline \textbf { Chooser 2 } & 45 \% & 30 \% & 25 \% \\
\hline \textbf { Divider } & 33.3 \% & 33.3 \% & 33.3 \% \\
\hline
\end{array}\)
Solution
Since the first chooser will clearly select Piece 1, the second chooser is left to select between Piece 2 and Piece 3, neither of which she values as a fair share (1/3 or about 33.3%). This example shows that this method does not guarantee a fair division.
To handle division with 3 or more parties, we’ll have to take a more clever approach.


5.7: Contracts
What you’ll learn to do: list and describe the elements of a legally enforceable contract, and explain the consequences of breach of contract
The contract is probably the most familiar legal concept in American society because it’s so central to deeply held convictions about the nature of our political, economic, and social life. In this section you’ll learn what contracts are and why they’re so central to business.
Learning Objectives
- Identify the four elements of a legally enforceable contract
- Explain the legal remedies for breach of contract
What Is a Contract?
A contract is a voluntary arrangement between two or more parties that is enforceable as a binding legal agreement.
A contract arises when the parties concur that there is an agreement. Formation of a contract generally requires an offer, acceptance, consideration, and a mutual intent to be bound. Each party to a contract must have capacity to enter the agreement. Minors, intoxicated persons, and those under a mental affliction may have insufficient capacity to enter a contract.
A contract may be oral or written, and the lack of a writing does not automatically make the contract void. English law and later U.S. law, however, recognized that oral contracts were subject to fraudulent claims by unscrupulous parties, and so developed the “Statute of Frauds” requiring that certain types of contracts be put into writing in order to be enforceable.
Under U.S. law, a contract must have four essential elements in order to be valid:
- Offer and Acceptance
- Consideration
- Competent Parties
- Legal Purpose
The following video explains these requirements in greater detail.
Breaches of Contracts
We speak of contracts as being either enforceable (legally binding) or unenforceable. An enforceable contract creates legal obligations, and the failure to comply with them creates a breach of contract.
When a party fails to live up to its obligations under the contract, he is said to have breached the agreement or to be in breach of contract . In the case of a breach of contract, the party that has suffered as a result of the breach may be granted one or more of the following remedies:
- Specific Performance . In some circumstances a court will order a party to perform his or her promise under the contract. In this case, the court will make an order of what is called “specific performance,” requiring that the contract be performed. There may be circumstances in which it would be unjust to permit the defaulting party simply to buy out the injured party with damages—for example, if an art collector purchased a rare painting and the vendor refused to deliver, the collector’s damages would be equal to the sum paid, but that wouldn’t exactly be just, since the contracted stipulated receipt of the painting.
- Damages . Damages may be general or consequential. General damages are those damages that naturally flow from a breach of contract. Consequential damages are those damages that, although not naturally flowing from a breach, are naturally supposed by both parties at the time of contract formation. An example would be when someone rents a car to get to a business meeting, but when that person arrives to pick up the car, it isn’t there. General damages would be the cost of renting a different car. Consequential damages would be the business lost if that person were unable to get to the meeting, if both parties knew the reason the party was renting the car. However, there is still a duty to mitigate the losses. The fact that the car wasn’t there doesn’t give the party a right not to attempt to rent another car.
- Discharge of Duties. There are some instances when, after the breach, both parties are relieved of their obligations under the contract. Let’s say you enter into a contract to purchase a house, but the house is destroyed by a tornado before you can complete the purchase. In this case, the court may decide that since the house is no longer there, the best remedy is to discharge the contract and relieve both parties of their obligation to perform under the contract.
Since almost every exchange in business creates some form of contract, it is essential that business owners as well as consumers understand the fundamental principles of contracts and contract laws.


10.1: Introduction
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- Jennifer Paris, Kristin Beeve, & Clint Springer
- College of the Canyons
Children have a sense of wonder and natural curiosity about objects and events in their environment. Just like scientists, they seek information and actively explore and investigate the world around them, try things out to see what happens, and confirm or adjust their expectations.
Science is a natural and developmentally appropriate focus for young children. Preschool science is about active learning, not memorizing scientific facts or watching the teacher perform science demonstrations. The purpose of preschool science is to nurture children’s habits of inquiry, critical thinking, creativity, innovative problem solving, open mindedness, and the motivation to learn. Preschool science guides children’s natural curiosity into opportunities to observe, explore, and inquire about basic phenomena and materials in their world.
From infancy, children gain knowledge and develop concepts about living things and physical objects. Preschool science provides children with focused experiences that allow them to learn ways to explore and extend their knowledge. Children begin to adopt scientific ideas and to acquire the basic skills and language of scientific inquiry (ways to explore and develop knowledge and understanding of scientific ideas). Making observations, posing questions, planning investigations, using tools to gather information, making predictions, recording information, and communicating findings and explanations all combine in an evolving process of developing science understanding and creating a disposition to choose to learn science in the future.
Science can be conducted in any preschool setting. All preschools, regardless of the level of resources and access to nature, can use their existing resources to create a program with meaningful science learning experiences. Pushing cars down an incline, building with blocks, manipulating tubes at the water table, or mixing clay with water are everyday play activities that engage children in experimenting with objects and materials. Collecting leaves, searching for insects in the yard, sorting and classifying fruits and vegetables, and sprouting seeds in pots engage children with living things. Experiences of child-initiated play are important as they provide children with opportunities to construct understanding and integrate knowledge. With teachers’ intentional planning, guidance, and support, children’s play and interactions with objects can become rich experiences of scientific inquiry and facilitate children’s knowledge and understanding of objects and events in the world.
Preschool teachers play a pivotal role in expanding children’s understanding of science concepts and developing children’s attitudes, skills, and the language of scientific inquiry. The teachers can focus children’s attention on particular science concepts, those that are developmentally appropriate, interesting, and engaging for both children and teachers. They can create engaging inquiry experiences, encouraging close observations of objects and events.
Children may draw the connection to their own growth and the growth of other animals and begin to develop a broader understanding of living things. Such experiences of scientific inquiry not only support children’s development of scientific knowledge, but provide a natural vehicle for developing children’s social skills, and their development in mathematics, language, literacy, and other domains.
Preschool teachers do not need to have extensive knowledge about science in order to teach it well, but they should be willing to research and gain general knowledge of the concepts and principles they explore with children. The kind and amount of information or knowledge they need to know is readily available through basic research. Acquiring some background knowledge about the topic helps teachers in planning inquiry experiences and challenging and supporting children through their explorations.
Teachers do not need to have answers to all the questions children will raise. Rather than providing children with answers, teachers can use children’s questions as a springboard for further investigations. They may say, “I don’t know. Let’s find out together.” It is essential that teachers become “scientists” together with children, model a questioning mind for children and think out loud, expressing interest and enthusiasm. Teachers’ thoughtful guidance and support through inquiry experiences builds a foundation for children’s understanding of basic science concepts, fosters a positive approach to learning, and develops learning skills and attitudes necessary for later success in science and in other subjects. [2]
References
[1] The California Preschool Curriculum Framework, Volume 3 by the California Department of Education is used with permission
[2] The California Preschool Curriculum Framework, Volume 3 by the California Department of Education is used with permission


13.17: Advantages of Employee Diversity
- Explain the advantages of employee diversity within organizations
While social justice, legal compliance, or maintaining industry standard employee environment protocols is typically the initial impetus behind [inclusion and diversity] efforts, many successful companies regard I&D as a source of competitive advantage, and specifically as a key enabler of growth.
—McKinsey & Company. Delivering Through Diversity , Jan 2018.
In the workplace, employee diversity can be a source of competitive advantage. Here are a few specific advantages:
- Leveraging a cross-cultural (in the broadest sense of the word) awareness to identify opportunities and avoid blind spots
- Increasing the productivity of employees who feel valued
- Improving an organization’s employer brand and, therefore, ability to recruit and retain talent
- Improving the market relevance and market value of a company/organization
As a case in point, consider Apple’s Health App that claims to allow you to “keep tabs on a wide array of data that matters to you—from measurements of your blood pressure and blood glucose to records for your weight and reproductive health.” Despite the promised capability to track reproductive health, the app was launched without a provision for monitoring menstrual cycles in what was critiqued as a stereotypical case of gender blindness. TechCrunch writer Sarah Perez summarized the disconnect, noting that menstrual tracking is a key function that “roughly half the population would expect to see included in a comprehensive health tracking app.” And as Perez noted , perhaps that’s not surprising given that 80 percent of Apple’s engineering staff is male.
Perez concludes: “the issue with the Health app is a perfect example of how not having the right [gender] balance internally can actually impact innovations and technology developments.” [1] Over a year after the product’s initial launch, Apple still hadn’t addressed the oversight and didn’t respond to Splinter writer Kashmir Hill’s request for comment , prompting her to suggest that the answer to her question why there’s still no period-tracking in HealthKit might be answered by the composition of the executive team: nine men and one woman.
For a financial performance view, let’s consider McKinsey Consulting’s research on diversity in the workplace. In a 2015 report titled Why Diversity Matters , McKinsey highlights the following findings, based on the composition of top management and boards:
- Companies in the top quartile for racial and ethnic diversity are 35 percent more likely to have financial returns above their respective national industry medians.
- Companies in the top quartile for gender diversity are 15 percent more likely to have financial returns above their respective national industry medians.
- Companies in the bottom quartile both for gender and for ethnicity and race are statistically less likely to achieve above-average financial returns than the average companies in the data set (that is, bottom-quartile companies are lagging rather than merely not leading).
- In the United States, there is a linear relationship between racial and ethnic diversity and better financial performance: for every ten percent increase in racial and ethnic diversity on the senior-executive team, earnings before interest and taxes (EBIT) rise 0.8 percent.
- Racial and ethnic diversity has a stronger impact on financial performance in the United States than gender diversity, perhaps because earlier efforts to increase women’s representation in the top levels of business have already yielded positive results.
In their 2018 publication, Delivering Through Diversity , McKinsey Consulting again reported finding a “positive, statistically significant correlation between executive team diversity and financial performance.” Although correlation is not causation, the report notes that “there is a real relationship between diversity and performance that has persisted over time and across geographies.” [2] The conclusion drawn from their 2015 Why Diversity Matters report still applies: “diversity is a competitive differentiator shifting market share toward more diverse companies.” [3]
- Perez, Sarah. " Apple Stops Ignoring Women’s Health With iOS 9 HealthKit Update, Now Featuring Period Tracking ," Tech Crunch , 09 Jun 2015. Web. 26 June 2018.
- McKinsey&Company. Delivering Through Diversity , Jan 2018. Web. 26 June 2018.
- McKinsey&Company. Diversity Matters , 2015. Web. 26 June 2018.
Contributors and Attributions
- Advantages of Employee Diversity. Authored by : Nina Burokas. Provided by : Lumen Learning. License : CC BY: Attribution
- hands. Authored by : rawpixel. Provided by : Pixabay. Located at : pixabay.com/en/man-people-achievement-african-3230661/. License : CC0: No Rights Reserved


5.3: Program Quality
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Overview
Program quality describes fundamental properties of the program’s source code and executable code, including reliability, robustness, usability, portability, maintainability, efficiency, and readability.
Discussion
Whatever the approach to development may be, the final program must satisfy some fundamental properties. The following properties are among the most important:
- Reliability : how often the results of a program are correct. This depends on the conceptual correctness of algorithms, and minimization of programming mistakes, such as mistakes in resource management (e.g., buffer overflows and race conditions) and logic errors (such as division by zero or off-by-one errors).
- Robustness : how well a program anticipates problems due to errors (not bugs). This includes situations such as incorrect, inappropriate or corrupt data, unavailability of needed resources such as memory, operating system services and network connections, user error, and unexpected power outages.
- Usability : the ergonomics of a program: the ease with which a person can use the program for its intended purpose or in some cases even unanticipated purposes. Such issues can make or break its success even regardless of other issues. This involves a wide range of textual, graphical and sometimes hardware elements that improve the clarity, intuitiveness, cohesiveness, and completeness of a program’s user interface.
- Portability : the range of computer hardware and operating system platforms on which the source code of a program can be compiled/interpreted and run. This depends on differences in the programming facilities provided by the different platforms, including hardware and operating system resources, expected behavior of the hardware and operating system, and availability of platform specific compilers (and sometimes libraries) for the language of the source code.
- Maintainability : the ease with which a program can be modified by its present or future developers in order to make improvements or customizations, fix bugs and security holes, or adapt it to new environments. Good practices during initial development make the difference in this regard. This quality may not be directly apparent to the end user but it can significantly affect the fate of a program over the long term.
- Efficiency /performance: the measure of system resources a program consumes (processor time, memory space, slow devices such as disks, network bandwidth and to some extent even user interaction): the less, the better. This also includes careful management of resources, for example cleaning up temporary files and eliminating memory leaks.
- Readability : the ease with which a human reader can comprehend the purpose, control flow , and operation of source code. It affects the aspects of quality above, including portability, usability and most importantly maintainability. Readability is important because programmers spend the majority of their time reading, trying to understand and modifying existing source code, rather than writing new source code. Unreadable code often leads to bugs, inefficiencies, and duplicated code .
Key Terms
- efficiency
- The measure of system resources a program consumes.
- maintainability
- The ease with which a program can be modified by its present or future developers.
- portability
- The range of computer hardware and operating system platforms on which the source code of a program can be compiled/interpreted and run.
- readability
- The ease with which a human reader can comprehend the purpose, control flow, and operation of source code.
- reliability
- How often the results of a program are correct.
- robustness
- How well a program anticipates problems due to errors.
- usability
- The ease with which a person can use the program.


6.9: References
Adler, R., Rosenfeld, L., & Proctor, R. (2018). Interplay: The process of interpersonal communication . Oxford University Press.
Barker, L.L., Edwards, R., Gaines, C., Gladney, K., & Holley, F. (1981). An investigation of proportional time spent in various communication activities by college students. Journal of Applied Communication Research, 8, 101-109.
Barnard, D. (2022, November 8). Average speaking rate and words per minute. VirtualSpeech. https://virtualspeech.com/blog/average-speaking-rate-words-per-minute
Burgoon, J., Mayew, W. J., Giboney, J. S., Elkins, A. C., Moffitt, K., Dorn, B., Byrd, M. & Spitzley, L. (2015). Which spoken language markers identify deception in high-stakes settings? Evidence from earnings conference calls. Journal of Language and Social Psychology, 35 (2). doi.org/10.1177/0261927X15586792
Editors of Encyclopedia Britannica. (n.d.) Quinceañera. In Encyclopedia Britannica . https://www.britannica.com/topic/quinceanera
Emanuel, R., Adams, J., Baker, K., Daufin, E. K., Ellington, C., Fitts, E., Himsel, J., Holladay, L., & Okeowo, D. (2008). How college students spend their time communicating. International Journal of Listening , 22, 13-28. doi.org/10.1080/10904010701802139
Floyd, J. J. (1985). Listening, a practical approach . Scott Foresman & Co.
Fundamentals of Public Speaking Florida State College at Jacksonville and Mary Lee Cunill, PhD. CC BY 4.0 .
Hall, E. T., & Hall, M. R. (2001). Key concepts: Underlying structures of culture. International HRM: Managing diversity in the workplace , 24 .
Hargie, O. (2010). Skilled interpersonal communication: Research, theory and practice (5th ed.). Taylor and Francis.
Hargie, O. (2021). Skilled interpersonal communication: Research, theory and practice (6th ed.) . Routledge.
Harwood, J. (2017). Understanding Communication and Aging (2nd ed.). Cognella, Inc..
Mallard, K. S. (1999). Lending an ear: The chair’s role as listener. The Department Chair, 9 (3), 1-13.
McCornack, S., & Morrison, K. (2019) Reflect & Relate: An introduction to interpersonal communication . Bedford/St. Martin's.
Shahadi, j. (2020, August 27). 90% of employers say working remotely hasn't hurt productivity. CNN Business . https://www.cnn.com/2020/08/27/success/work-from-home-employer-plans-for-more-flexible-policies/index.html
Tannen, D. (2013). You just don't understand: Women and men in conversation . Virago.
Watson, K. W., Barker, L. L., & Weaver, J. B., III. (1995). The listening styles profile (LSP-16): Development and validation of an instrument to assess four listening styles. International Journal of Listening, 9 (1), 1-13.
Watson, K. W., Barker, L. L., & Weaver, J. B., III. (1992, March). Development and validation of the Listener Preference Profile. Paper presented at the International Listening Association in Seattle, WA.