Terminology and definitions.

General.

Around the world, the English terms "youth", "adolescent", "teenager", "kid", and "young person" are interchanged, often meaning the same thing, but they are occasionally differentiated. "Youth" can be referred to as the time of life when one is young. This involves childhood, and the time of life which is neither childhood nor adulthood, but rather somewhere in between. "Youth" also identifies a particular mindset of attitude, as in "He is very "youth"ful". For certain uses, such as employment statistics, the term also sometimes refers to individuals from the ages of 14 to 21. However, the term "adolescence" refers to a specific age range during a specific developmental period in a person's life, unlike youth which is a socially constructed category.  The United Nations defines "youth" as persons between the ages of 15 and 24 with all UN statistics based on this range, the UN states education as a source for these statistics. The UN also recognizes that this varies without prejudice to other age groups listed by member states such as 18–30. A useful distinction within the UN itself can be made between teenagers (i.e. those between the ages of 13 and 19) and young adults (those between the ages of 18 and 32). While seeking to impose some uniformity on statistical approaches, the UN itself is aware of contradictions between approaches in its own statutes. Hence under the 15–24 definition (introduced in 1981) children are defined as those under the age of 14 while under the 1979 Convention on the Rights of the Child, those under the age of 18 are regarded as children. The UN also states they are aware that several definitions exist for youth within UN entities such as Youth Habitat 15–32 and African Youth Charter 15–35.  Although linked to biological processes of development and aging, "youth" is also defined as a social position that reflects the meanings different cultures and societies give to individuals between childhood and adulthood. The term in itself when referred to in a manner of social position, can be ambiguous when applied to someone of an older age with very low social position; potentially when still dependent on their guardians. Scholars argue that age-based definitions have not been consistent across cultures or times and that thus it is more accurate to focus on social processes in the transition to adult independence for defining youth.  Youth is the stage of constructing the self-concept. The self-concept of youth is influenced by variables such as peers, lifestyle, gender, and culture. It is a time of a person's life when their choices are most likely to affect their future.

Other definitions.

In much of sub-Saharan Africa, the term "youth" is associated with young men from 15 to 30 or 35 years of age. Youth in Nigeria includes all members of the Federal Republic of Nigeria aged 18–35. Many African girls experience youth as a brief interlude between the onset of puberty and marriage and motherhood. But in urban settings, poor women are often considered youth much longer, even if they bear children outside of marriage. Varying culturally, the gender constructions of youth in Latin America and Southeast Asia differ from those of sub-Saharan Africa. In Vietnam, widespread notions of youth are sociopolitical constructions for both sexes between the ages of 15 and 35.  In Brazil, the term "youth" refers to people of both sexes from 15 to 29 years old. This age bracket reflects the influence on Brazilian law of international organizations like the World Health Organization (WHO). It is also shaped by the notion of adolescence that has entered everyday life in Brazil through a discourse on children's rights.  The intergovernmental organization Organisation for Economic Co-operation and Development defines "youth" as "those between 15 and 29 years of age".  August 12 was declared International Youth Day by the United Nations.

Youth rights.

Children's rights cover all the rights that belong to children. When they grow up they are granted with new rights (like voting, consent, driving, etc.) and duties (criminal response, etc.). There are different minimum limits of age at which youth are not free, independent or legally competent to take some decisions or actions. Some of these limits are voting age, age of candidacy, age of consent, age of majority, age of criminal responsibility, drinking age, driving age, etc. After youth reach these limits they are free to vote, have sexual intercourse, buy or consume alcohol beverages or drive cars, etc.

Voting age.

Voting age is the minimum age established by law that a person must attain to be eligible to vote in a public election. Typically, the age is set at 18 years; however, ages as low as 16 and as high as 21 exist (see list below). Studies show that 21% of all 18 year olds have experience with voting. This is an important right since, by voting they can support politics selected by themselves and not only by people of older generations.

Age of candidacy.

Age of candidacy is the minimum age at which a person can legally qualify to hold certain elected government offices. In many cases, it also determines the age at which a person may be eligible to stand for an election or be granted ballot access.

Age of consent.

The age of consent is the age at which a person is considered legally competent to consent to sexual acts, and is thus the minimum age of a person with whom another person is legally permitted to engage in sexual activity. The distinguishing aspect of the age of consent laws is that the person below the minimum age is regarded as the victim, and their sex partner as the offender.

Defense of infancy.

The defense of infancy is a form of defense known as an excuse so that defendants falling within the definition of an "infant" are excluded from criminal liability for their actions, if at the relevant time, they had not reached an age of criminal responsibility. This implies that children lack the judgment that comes with age and experience to be held criminally responsible. After reaching the initial age, there may be levels of responsibility dictated by age and the type of offense committed.

Drinking age.

The legal drinking age is the age at which a person can consume or purchase alcoholic beverages. These laws cover a wide range of issues and behaviors, addressing when and where alcohol can be consumed. The minimum age alcohol can be legally consumed can be different from the age when it can be purchased in some countries. These laws vary among different countries and many laws have exemptions or special circumstances. Most laws apply only to drinking alcohol in public places, with alcohol consumption in the home being mostly unregulated (an exception being the UK, which has a minimum legal age of five for supervised consumption in private places). Some countries also have different age limits for different types of alcoholic drinks.

Driving age.

Driving age is the age at which a person can apply for a driver's license. Countries with the lowest driving ages (below 17) are Argentina, Australia, Canada, El Salvador, Iceland, Israel, Estonia, Macedonia, Malaysia, New Zealand, Norway, the Philippines, Russia, Saudi Arabia, Slovenia, Sweden, the United Kingdom (Mainland) and United States. The Canadian province of Alberta and several U.S. states permit youth driving as low as 14. Niger has the highest minimum driving age in the world at 23. In India, driving is legal after getting a license at the age of 18.

Legal working age.

The legal working age is the minimum age required by law for a person to work, in each country or jurisdiction. The threshold of adulthood, or "the age of majority" as recognized or declared in law in most countries has been set at age 18. Some types of labor are commonly prohibited even for those above the working age, if they have not reached yet the age of majority. Activities that are dangerous, harmful to the health or that may affect the morals of minors fall into this category.

Student rights in higher education.

Student rights are those rights, such as civil, constitutional, contractual and consumer rights, which regulate student rights and freedoms and allow students to make use of their educational investment. These include such things as the right to free speech and association, to due process, equality, autonomy, safety and privacy, and accountability in contracts and advertising, which regulate the treatment of students by teachers and administrators.

Smoking age.

The smoking age is the minimum age a person can buy tobacco, and/or smoke in public. Most countries regulate this law at the national level while at some it is done by the state or province.

School and education.

Young people spend much of their lives in educational settings, and their experiences in schools, colleges and universities can shape much of their subsequent lives. Research shows that poverty and income affect the likelihood for the incompletion of high school. These factors also increase the likelihood for the youth to not go to a college or university. In the United States, 12.3 percent of young people ages 16 to 24 are disconnected, meaning they are neither in school nor working.

Health and mortality.

The leading causes of morbidity and mortality among youth and adults are due to certain health-risk behaviors. These behaviors are often established during youth and extend into adulthood. Since the risk behaviors in adulthood and youth are interrelated, problems in adulthood are preventable by influencing youth behavior.  A 2004 mortality study of youth (defined in this study as ages 10–24) mortality worldwide found that 97% of deaths occurred in low to middle-income countries, with the majority in southeast Asia and sub-Saharan Africa. Maternal conditions accounted for 15% of female deaths, while HIV/AIDS and tuberculosis were responsible for 11% of deaths; 14% of male and 5% of female deaths were attributed to traffic accidents, the largest cause overall. Violence accounted for 12% of male deaths. Suicide was the cause of 6% of all deaths.  The U.S. Centers for Disease Control and Prevention developed its Youth Risk Behavior Surveillance System (YRBSS) in 2003 to help assess risk behavior. YRBSS monitors six categories of priority health-risk behaviors among youth and young adults. These are behaviors that contribute to unintentional injuries and violence;  YRBSS includes a national school-based survey conducted by CDC as well as state and local school-based surveys conducted by education and health agencies.  Universal school-based interventions such as formal classroom curricula, behavioural management practices, role‐play, and goal‐setting may be effective in preventing tobacco use, alcohol use, illicit drug use, antisocial behaviour, and improving physical activity of young people.

Obesity.

Obesity now affects one in five children in the United States, and is the most prevalent nutritional disease of children and adolescents in the United States. Although obesity-associated morbidities occur more frequently in adults, significant consequences of obesity as well as the antecedents of adult disease occur in obese children and adolescents.  Discrimination against overweight children begins early in childhood and becomes progressively institutionalized. Obese children may be taller than their non-overweight peers, in which case they are apt to be viewed as more mature. The inappropriate expectations that result may have an adverse effect on their socialization.  Many of the cardiovascular consequences that characterize adult-onset obesity are preceded by abnormalities that begin in childhood. Hyperlipidemia, hypertension, and abnormal glucose tolerance occur with increased frequency in obese children and adolescents. The relationship of cardiovascular risk factors to visceral fat independent of total body fat remains unclear. Sleep apnea, pseudotumor cerebri, and Blount's disease represent major sources of morbidity for which rapid and sustained weight reduction is essential. Although several periods of increased risk appear in childhood, it is not clear whether obesity with onset early in childhood carries a greater risk of adult morbidity and mortality.

Bullying.

Bullying among school-aged youth is increasingly being recognized as an important problem affecting well-being and social functioning. While a certain amount of conflict and harassment is typical of youth peer relations, bullying presents a potentially more serious threat to healthy youth development. The definition of bullying is widely agreed on in literature on bullying.  The majority of research on bullying has been conducted in Europe and Australia. Considerable variability among countries in the prevalence of bullying has been reported. In an international survey of adolescent health-related behaviors, the percentage of students who reported being bullied at least once during the current term ranged from a low of 15% to 20% in some countries to a high of 70% in others. Of particular concern is frequent bullying, typically defined as bullying that occurs once a week or more. The prevalence of frequent bullying reported internationally ranges from a low of 1.9% among one Irish sample to a high of 19% in a Malta study.  Research examining characteristics of youth involved in bullying has consistently found that both bullies and those bullied demonstrate poorer psychosocial functioning than their non-involved peers. Youth who bully others tend to demonstrate higher levels of conduct problems and dislike of school, whereas youth who are bullied generally show higher levels of insecurity, anxiety, depression, loneliness, unhappiness, physical and mental symptoms, and low self-esteem. Males who are bullied also tend to be physically weaker than males in general. The few studies that have examined the characteristics of youth who both bully and are bullied found that these individuals exhibit the poorest psychosocial functioning overall.

Sexual health and politics.

General.

Globalization and transnational flows have had tangible effects on sexual relations, identities, and subjectivities. In the wake of an increasingly globalized world order under waning Western dominance, within ideologies of modernity, civilization, and programs for social improvement, discourses on population control,'safe sex', and'sexual rights'. Sex education programmes grounded in evidence-based approaches are a cornerstone in reducing adolescent sexual risk behaviours and promoting sexual health. In addition to providing accurate information about consequences of Sexually transmitted disease or STIs and early pregnancy, such programmes build life skills for interpersonal communication and decision making. Such programmes are most commonly implemented in schools, which reach large numbers of teenagers in areas where school enrollment rates are high. However, since not all young people are in school, sex education programmes have also been implemented in clinics, juvenile detention centers and youth-oriented community agencies. Notably, some programmes have been found to reduce risky sexual behaviours when implemented in both school and community settings with only minor modifications to the curricula.

Philippines.

The Sangguniang Kabataan ("Youth Council" in English), commonly known as SK, was a youth council in each barangay (village or district) in the Philippines, before being put "on hold", but not quite abolished, prior to the 2013 barangay elections. The council represented teenagers from 15 to 17 years old who have resided in their barangay for at least six months and registered to vote. It was the local youth legislature in the village and therefore led the local youth program and projects of the government. The Sangguniang Kabataan was an offshoot of the KB or the "Kabataang Barangay" (Village Youth) which was abolished when the Local Government Code of 1991 was enacted.

In the Global South.

The vast majority of young people live in developing countries: according to the UN, globally around 85 per cent of 15- to 25-year-olds live in developing countries, a figure projected to grow 89.5 per cent by 2025. Moreover, this majority are extremely diverse: some live in rural areas but many inhabit the overcrowded metropolises of India, Mongolia and other parts of Asia and in South America, some live traditional lives in tribal societies, while others participate in global youth culture in ghetto contexts.  Many young lives in developing countries are defined by poverty, some suffer from famine and a lack of clean water, while involvement in armed conflict is all common. Health problems are rife, especially due to the prevalence of HIV/AIDS in certain regions. The United Nations estimates that 200 million young people live in poverty, 130 million are illiterate and 10 million live with HIV/AIDS.

Youth is the time of life when one is young, and often means the time between childhood and adulthood (maturity). It is also defined as "the appearance, freshness, vigor, spirit, etc., characteristic of one who is young". Its definitions of a specific age range varies, as youth is not defined chronologically as a stage that can be tied to specific age ranges; nor can its end point be linked to specific activities, such as taking unpaid work or having sexual relations.

La jeunesse est une classe d'âge réunissant une population mineure, qui varie selon les lois des pays, et majeure. Pour la sociologie, le terme jeunesse fait référence au temps entre l'enfance et l'âge adulte. Ce temps s'allonge de plus en plus avec le recul général de l'entrée dans la vie active.


Rationale.

Seismic waves are elastic waves that propagate through the Earth with a finite velocity, governed by the elastic properties of the rock in which they are travelling. At an interface between two rock types, with different acoustic impedances, the seismic energy is either refracted, reflected back towards the surface or attenuated by the medium. The reflected energy arrives at the surface and is recorded by geophones that are placed at a known distance away from the source of the waves. When a geophysicist views the recorded energy from the geophone, they know both the travel time and the distance between the source and the receiver, but not the distance down to the reflector.  In the simplest geological setting, with a single horizontal reflector, a constant velocity and a source and receiver at the same location (referred to as zero-offset, where offset is the distance between the source and receiver), the geophysicist can determine the location of the reflection event by using the relationship:  where d is the distance, v is the seismic velocity (or rate of travel) and t is the measured time from the source to the receiver.  In this case, the distance is halved because it can be assumed that it only took one-half of the total travel time to reach the reflector from the source, then the other half to return to the receiver.  The result gives us a single scalar value, which actually represents a half-sphere of distances, from the source/receiver, which the reflection could have originated from. It is a half-sphere, and not a full sphere, because we can ignore all possibilities that occur above the surface as unreasonable. In the simple case of a horizontal reflector, it can be assumed that the reflection is located vertically below the source/receiver point (see diagram).  The situation is more complex in the case of a dipping reflector, as the first reflection originates from further up the direction of dip (see diagram) and therefore the travel-time plot will show a reduced dip that is defined the “migrator’s equation” :  where is the "apparent dip" and is the "true dip".  Zero-offset data is important to a geophysicist because the migration operation is much simpler, and can be represented by spherical surfaces. When data is acquired at non-zero offsets, the sphere becomes an ellipsoid and is much more complex to represent (both geometrically, as well as computationally).

Use.

For a geophysicist, complex geology is defined as anywhere there is an abrupt or sharp contrast in lateral and/or vertical velocity (e.g. a sudden change in rock type or lithology which causes a sharp change in seismic wave velocity).  Some examples of what a geophysicist considers complex geology are: faulting, folding, (some) fracturing, salt bodies, and unconformities. In these situations a form of migration is used called pre-stack migration (PreSM), in which all traces are migrated before being moved to zero-offset. Consequently, much more information is used, which results in a much better image, along with the fact that PreSM honours velocity changes more accurately than post-stack migration.

Types of migration.

Depending on budget, time restrictions and the subsurface geology, geophysicists can employ 1 of 2 fundamental types of migration algorithms, defined by the domain in which they are applied: time migration and depth migration.

Time migration.

Time migration is applied to seismic data in time coordinates. This type of migration makes the assumption of only mild lateral velocity variations and this breaks down in the presence of most interesting and complex subsurface structures, particularly salt. Some popularly used time migration algorithms are: Stolt migration, Gazdag and Finite-difference migration.

Depth migration.

Depth Migration is applied to seismic data in depth (regular Cartesian) coordinates, which must be calculated from seismic data in time coordinates. This method does therefore require a velocity model, making it resource-intensive because building a seismic velocity model is a long and iterative process. The significant advantage to this migration method is that it can be successfully used in areas with lateral velocity variations, which tend to be the areas that are most interesting to petroleum geologists. Some of the popularly used depth migration algorithms are Kirchhoff depth migration, Reverse Time Migration (RTM), Gaussian Beam Migration and Wave-equation migration.

Resolution.

The goal of migration is to ultimately increase spatial resolution and one of the basic assumptions made about the seismic data is that it only shows primary reflections and all noise has been removed. In order to ensure maximum resolution (and therefore maximum uplift in image quality) the data should be sufficiently pre-processed before migration. Noise that may be easy to distinguish pre-migration could be smeared across the entire aperture length during migration, reducing image sharpness and clarity.  A further basic consideration is whether to use 2D or 3D migration. If the seismic data has an element of cross-dip (a layer that dips perpendicular to the line of acquisition) then the primary reflection will originate from out-of-plane and 2D migration cannot put the energy back to its origin. In this case, 3D migration is needed to attain the best possible image.  Modern seismic processing computers are more capable of performing 3D migration, so the question of whether to allocate resources to performing 3D migration is less of a concern.

Graphical migration.

The simplest form of migration is that of graphical migration. Graphical migration assumes a constant velocity world and zero-offset data, in which a geophysicist draws spheres or circles from the receiver to the event location for all events. The intersection of the circles then form the reflector's "true" location in time or space. An example of such can be seen in the diagram.

Technical details.

Migration of seismic data is the correction of the flat-geological-layer assumption by a numerical, grid-based spatial convolution of the seismic data to account for dipping events (where geological layers are not flat). There are many approaches, such as the popular Kirchhoff migration, but it is generally accepted that processing large spatial sections (apertures) of the data at a time introduces fewer errors, and that depth migration is far superior to time migration with large dips and with complex salt bodies.  Basically, it repositions/moves the energy (seismic data) from the recorded locations to the locations with the correct common midpoint (CMP). While the seismic data is received at the proper locations originally (according to the laws of nature), these locations do not correspond with the assumed CMP for that location. Though stacking the data without the migration corrections yields a somewhat inaccurate picture of the subsurface, migration is preferred for better most imaging recorder to drill and maintain oilfields. This process is a central step in the creation of an image of the subsurface from active source seismic data collected at the surface, seabed, boreholes, etc., and therefore is used on industrial scales by oil and gas companies and their service providers on digital computers.  Explained in another way, this process attempts to account for wave dispersion from dipping reflectors and also for the spatial and directional seismic wave speed (heterogeneity) variations, which cause wavefields (modelled by ray paths) to bend, wave fronts to cross (caustics), and waves to be recorded at positions different from those that would be expected under straight ray or other simplifying assumptions. Finally, this process often attempts to also preserve and extract the formation interface reflectivity information imbedded in the seismic data amplitudes, so that they can be used to reconstruct the elastic properties of the geological formations (amplitude preservation, seismic inversion). There are a variety of migration algorithms, which can be classified by their output domain into the broad categories of time migration or depth migration, and pre-stack migration or post-stack migration (orthogonal) techniques. Depth migration begins with time data converted to depth data by a spatial geological velocity profile. Post-stack migration begins with seismic data which has already been stacked, and thus already lost valuable velocity analysis information.

Seismic migration is the process by which seismic events are geometrically re-located in either space or time to the location the event occurred in the subsurface rather than the location that it was recorded at the surface, thereby creating a more accurate image of the subsurface. This process is necessary to overcome the limitations of geophysical methods imposed by areas of complex geology, such as: faults, salt bodies, folding, etc. Migration moves dipping reflectors to their true subsurface positions and collapses diffractions, resulting in a migrated image that typically has an increased spatial resolution and resolves areas of complex geology much better than non-migrated images. A form of migration is one of the standard data processing techniques for reflection-based geophysical methods (seismic reflection and ground-penetrating radar)

La migration sismique est un procédé d'amélioration de l'imagerie sismique utilisé généralement en sismique pétrolière consistant à replacer les arrivées sur une section sismique à leurs emplacements réels à l'aide de différentes méthodes mathématiques ou numériques (migration de Kirchoff, migration par équation d'onde,...)


Early life.

Muhammad Ahmad was born on 12 August 1844 at Labab Island, Dongola in northern Sudan to a humble Nubian family of boat-builders who trace their descent from the Islamic prophet Muhammad through the line of his grandson Hassan. When Muhammad Ahmad was still a child, the family moved to the town of Karari, north of Omdurman, where Muhammad Ahmad's father, Abdullah, could find an adequate supply of timber for his successful boat-building business.  While his siblings joined his father's trade, Muhammad Ahmad showed a proclivity for religious study. He studied first under Sheikh al-Amin al-Suwaylih in the Gezira region around Khartoum, and subsequently under Sheikh Muhammad al-Dikayr 'Abdallah Khujali near the town of Berber in North Sudan. Determined to live a life of asceticism, mysticism and worship, in 1861 he sought out Sheikh Muhammad Sharif Nur al-Dai'm, the grandson of the founder of the Samaniyya Sufi sect in Sudan. Muhammad Ahmad stayed with Sheikh Muhammad Sharif for seven years, during which time he was recognized for his piety and asceticism. Near the end of this period, he was awarded the title of Sheikh himself, and began to travel around the country on religious missions. He was permitted to give tariqa and Uhūd to new followers.  In 1870, his family moved again in search for timber, this time to Aba Island on the White Nile south of Khartoum. On Aba Island, Muhammad Ahmad built a mosque and started to teach the Qur'an. He soon gained a notable reputation among the local population as an excellent speaker and mystic. The broad thrust of his teaching followed that of other reformers, his Islam was one devoted to the words of Muhammad and based on a return to the virtues of strict devotion, prayer, and simplicity as laid down in the Qur'an.  In 1872, Muhammad Ahmad invited Sheikh Sharif to move to al-Aradayb, an area on the White Nile neighboring Aba Island. Despite initially amicable relations, in 1878 the two religious leaders had a dispute motivated by Sheikh Sharif's resentment of his former student's growing popularity. As a result, Sheikh Sharif expelled his former student from the Samaniyya order, and despite numerous attempts at reconciliation by Muhammad Ahmad, his mentor refused to make peace.  After recognizing that the split with Sheikh Sharif was irreconcilable, Muhammad Ahmad approached another respected leader of the Samaniyya order named Sheikh al-Qurashi wad al-Zayn. Muhammad Ahmad resumed his life of piety and religious devotion at Aba Island. During this period, he also traveled to the province of Kordofan, west of Khartoum, where he visited with the notables of the capital, El-Obeid, who were enmeshed in a power struggle between two rival claimants to the governorship of the province.  On 25 July 1878, Sheikh al-Qurashi died and his followers recognized Muhammad Ahmad as their new leader. Around this time, Muhammad Ahmad first met Abdallahi bin Muhammad al-Ta'aishi, who was to become his chief deputy and successor in the years to come.

Announcement of the Mahdiyya.

On 29 June 1881, Muhammad Ahmad publicly announced his Mahdiyya so as to prepare the way for the second coming of the Prophet Isa (Jesus). In part, his claim was based on his status as a prominent Sufi sheikh with a large following in the Samaniyya order and among the tribes in the area around Aba Island. Yet the idea of the Mahdiyya had been central to the belief of the Samaniyya prior to Muhammad Ahmad's manifestation. The previous Samaniyya leader, Sheikh al-Qurashi Wad al-Zayn, had asserted that the long-awaited-for redeemer would come from the Samaniyya line. According to Sheikh al-Qurashi, the Mahdi would make himself known through a number of signs, some established in the early period of Islam and recorded in the Hadith literature, and others having a more distinctly local origin, such as the prediction that the Mahdi would ride the sheikh's pony and erect a dome over his grave after his death.  Drawing from aspects of the Sufi tradition that were intimately familiar to both his followers and his opponents, Muhammad Ahmad claimed that he had been appointed as the Mahdi by a prophetic assembly or hadra (Arabic: Al-Hadra Al-Nabawiyya, الحضرة النبوية). A hadra, in the Sufi tradition, is a gathering of all the prophets from the time of Adam to Muhammad, as well as many Sufi holy men who are believed to have reached the highest level of affinity with the divine during their lifetime. The hadra is chaired by the Prophet Muhammad, known as Sayyid al-Wujud, and at his side are the seven Qutb, the most senior of whom is known as Ghawth az-Zaman. The hadra was also the source of a number of central beliefs about the Mahdi, including that he was created from the sacred light at the centre of the Prophet's heart, and that all living creatures had acknowledged the Mahdi's claim since his birth.  Muhammad Ahmad framed the Mahdiyya as a return to the early days of Islam, when the Muslim community, or Ummah, was unified under the guidance of the Prophet Muhammad and his immediate successors. Later, in order to distinguish his followers from adherents of other Sufi sects, he forbade the use of the word darwish (commonly known as "dervish" in English) to describe his followers, replacing it with the title Ansar, the term the Prophet Muhammad used for the people of Medina who welcomed him and his followers after their flight from Mecca.

Response of the 'Ulema.

Despite his popularity among the clerics of the Samaniyya and other sects, and among the tribes of western Sudan, some of the Ulema, or orthodox religious authorities, rejected Muhammad Ahmad's claim to be the Mahdi. Among his most prominent critics were the Sudanese Ulema loyal to the Ottoman Sultan and employed by the Turco-Egyptian government, such as the Mufti Shakir al-Ghazi, who sat on the Council of Appeal in Khartoum, and the Qadi Ahmad al-Azhari in Kordofan.  These critics were careful not to deny the concept of the Mahdi as such, but rather to discredit Muhammad Ahmad's claim to it. They pointed out that Muhammad Ahmad's manifestation did not conform to the prophecies laid out in the Hadith literature. In particular, they argued for the political interests of the Turco-Egyptian government and its British rulers, that his manifestation did not conform with the "time of troubles" "when the land is filled with oppression, tryanny, and enmity".

Advance of the rebellion.

Egyptian authorities attempted to arrest him for inciting the Sudanese people to achieve their independence and overthrow their oppressors. A military expedition was sent to reassert the government's authority on Aba Island, but the government's forces were ambushed and nearly annihilated by the Mahdi's followers.  The Mahdi and a party of his followers, the "Ansār" (helpers, known in the West as "the Dervishes"), made a long march to Kurdufan. There he gained a large number of recruits, especially from the Baqqara, and notable leaders such as Sheikh Madibbo ibn Ali of Rizeigat and Abdallahi ibn Muhammad of Ta'aisha tribes. They were also joined by the Hadendoa Beja, who were rallied to the Mahdi by an Ansār captain in east of Sudan in 1883, Osman Digna. The Mahdist revolution was backed by the Northern and western regions of Sudan, and it also found a great support from the Nuer, Shilluk and Anuak tribes from southern Sudan in addition to the tribes of Bahr Alghazal, a thing which affirmed that the Mahdist revolution was a national revolution and not a regional one. In addition to unifying different tribes, the revolution also cut across religious divides, despite its religious origins. The Mahdi was supported by non-Muslims and Muslims alike. This had important implications for the slave trade, because the Mahdi, going against traditional Islamic injunctions, allowed the enslavement of free Muslims who did not support him and forbade the enslavement of the traditionally hunted non-Muslims who did support him.  Late in 1883, the Ansār, armed only with spears and swords, overwhelmed a 4,000-man Egyptian force not far from El-Obeid, and seized their rifles and ammunition. The Mahdi followed up this victory by laying siege to El-Obeid and starving it into submission after four months. The town remained the headquarters of the Ansar for much of the decade.  The Ansār, now 40,000 strong, then defeated an 8,000-man Egyptian relief force led by British officer William Hicks at Sheikan, in the battle of El Obeid. The defeat of Hicks sealed the fate of Darfur, which until then had been effectively defended by Rudolf Carl von Slatin. Jabal Qadir in the south was also taken. The western half of Sudan was now firmly in Ansārī hands.  Their success emboldened the Hadendoa, who under the generalship of Osman Digna wiped out a smaller force of Egyptians under the command of Colonel Valentine Baker near the Red Sea port of Suakin. Major-General Gerald Graham was sent with a force of 4,000 British soldiers and defeated Digna at El Teb on February 29, but were themselves hard-hit two weeks later at Tamai. Graham eventually withdrew his forces.

Khartoum.

After much debate the British decided to abandon the Sudan in December 1883, holding only several northern towns and Red Sea ports, such as Khartoum, Kassala, Sannar, and Sawakin. The evacuation of Egyptian troops and officials and other foreigners from Sudan was assigned to General Gordon, who had been reappointed governor general with orders to return to Khartoum and organize a withdrawal of the Egyptian garrisons there.

Arrival of Gordon.

Gordon reached Khartoum in February 1884. At first he was greeted with jubilation as many of the tribes in the immediate area were at odds with the Mahdists. Transportation northward was still open and the telegraph lines intact. However, the uprising of the Beja soon after his arrival changed things considerably, reducing communications to runners.  Gordon considered the routes northward to be too dangerous to extricate the garrisons and so pressed for reinforcements to be sent from Cairo to help with the withdrawal. He also suggested that his old enemy Al-Zubayr Rahma Mansur, a fine military commander, be given tacit control of the Sudan in order to provide a counter to the Ansār. London rejected both proposals, and so Gordon prepared for a fight.  In March 1884, Gordon tried to stage an offensive to clear the road northward to Egypt but a number of the officers in the Egyptian force went over to the enemy and their forces fled the field after firing a single salvo. This convinced him that he could carry out only defensive operations and he returned to Khartoum to construct defensive works.  By April 1884, Gordon had managed to evacuate some 2500 of the foreign population that were able to make the trek northwards. His mobile force under Colonel Stewart then returned to the city after repeated incidents where the 200 or so Egyptian forces under his command would turn and run at the slightest provocation.

Siege.

That month the Ansār reached Khartoum and Gordon was completely cut off. Nevertheless, his defensive works, consisting mainly of mines, proved so frightening to the Ansār that they were unable to penetrate into the city. Stewart maintained a number of small skirmishes using gunboats on the Nile once the waters rose, and in August managed to recapture Berber for a short time. However, Stewart was killed soon after in another foray from Berber to Dongola, a fact Gordon only learned about in a letter from the Mahdi himself.  Under increasing pressure from the public to support him, the British Government under Prime Minister Gladstone eventually ordered Lord Garnet Joseph Wolseley to relieve Gordon. He was already deployed in Egypt due to the attempted coup there earlier, and was able to form up a large force of infantry, moving forward at an extremely slow rate. Realizing they would take some time to arrive, Gordon pressed for him to send forward a "flying column" of camel-borne troops across the Bayyudah Desert from Wadi Halfa under the command of Brigadier-General Sir Herbert Stuart. This force was attacked by the Hadendoa Beja, or "Fuzzy Wuzzies", twice, first at the Battle of Abu Klea and two days later nearer Metemma. Twice the British square held and the Mahdists were repelled with heavy losses.  At Metemma, north of Khartoum, Wolseley's advance guard met four of Gordon's steamers, sent down to provide speedy transport for the first relieving troops. They gave Wolseley a dispatch from Gordon claiming that the city was about to fall. However, only moments later a runner brought in a message claiming the city could hold out for a year. Deciding to believe the latter, the force stopped while they refit the steamers to hold more troops.

Fall of Khartoum.

They finally arrived in Khartoum on 28 January 1885 to find the town had fallen during the Battle of Khartoum two days earlier. When the Nile had receded from flood stage, one of Gordon's pashas (officers), Faraz Pasha, had opened the river gates and let the Ansār in. The garrison was slaughtered, the male population massacred, the women and children enslaved, and Gordon was killed fighting the Mahdi's warriors on the steps of the palace, hacked to pieces and beheaded. When Gordon's head was unwrapped at the Mahdi's feet, he ordered the head transfixed between the branches of a tree "where all who passed it could look in disdain, children could throw stones at it and the hawks of the desert could sweep and circle above." When Wolseley's force arrived, they retreated after attempting to force their way to the center of the town on ships, being met with a hail of fire.  The Mahdi Army continued its sweep of victories. Kassala and Sannar fell soon after and by the end of 1885 the Ansār had begun to move into the southern regions of Sudan. In all Sudan, only Suakin, reinforced by Indian troops, and Wadi Halfa on the northern frontier remained in Anglo-Egyptian hands.

Death and succession.

Six months after the capture of Khartoum, Muhammad Ahmad died of typhus. He was buried in Omdurman near the ruins of Khartoum. The Mahdi had planned for this eventuality and chose three deputies to replace him.  After the final defeat of the Khalifa by the British under General Kitchener in 1898, Muhammad Ahmad's tomb was destroyed and his bones were thrown into the Nile. General Kitchener was said to have retained his skull. Allegedly the skull was later buried at Wadi Halfa. The tomb was eventually rebuilt.

Aftermath.

Political heritage.

Muhammed Ahmad's posthumous son, Abd al-Rahman al-Mahdi, whom the British considered important as a popular leader of the Mahdists, became a leader of the neo-Mahdist movement in the Anglo-Egyptian Sudan. The Sudanese considered Abd al-Rahman to be the King of Sudan when the country gained independence, but he declined the title for spiritual reasons. 'Abd al-Rahman sponsored the Umma (Nation) political Party in the period before and just after Sudan became independent in 1956.  In modern-day Sudan, Muhammad Ahmad is sometimes seen as a precursor of Sudanese nationalism. The Umma party claim to be his political descendants. Their leader Imam Sadiq al-Mahdi, is the great-great-grandson of Muhammad Ahmad, and also the imam of the Ansar, the religious order that pledges allegiance to Muhammad Ahmad. Sadiq al-Mahdi was a democratic leader and Prime Minister of Sudan on two occasions: first briefly in 1966–67, and then between 1986 and 1989.

Muhammad Ahmad bin Abd Allah (; 12 August 1844 – 22 June 1885) was a Nubian religious leader of the Samaniyya order in Sudan who, as a youth, combined orthodox religious study with a mystical interpretation of Islam. On 29 June 1881, he was proclaimed the Mahdi by his disciples, the messianic redeemer of the Islamic faith. His proclamation came during a period of widespread resentment among the Sudanese population towards the oppressive policies of the Turco-Egyptian rulers and was supported by the messianic belief popular among the various Sudanese religious sects of the time. He led a successful war against Ottoman-Egyptian military rule and achieved a remarkable victory over the British. He then created a vast Islamic state extending from the Red Sea to Central Africa and founded a movement that remained influential in Sudan a century later.

Muhammad Ahmad ibn Abd Allah Al-Mahdi (en arabe : محمد أحمد ابن عبد الله), né le à Dongola et mort le à Khartoum, est un chef politique religieux musulman, fondateur d'un mouvement et d'un État théocratique sur le territoire du Soudan.


Jambo Bwana.

In 1982, the Kenyan hostel band Them Mushrooms (now known as Uyoga) released the Swahili song "Jambo Bwana" ("Hello Mister"), which repeats the phrase "Hakuna matata" in its refrain. The song was written by band leader John Katana.

Jambo – Hakuna Matata.

In 1983, German group Boney M. released "Jambo—Hakuna Matata", an English-language version of Them Mushrooms song Jambo Bwana. Liz Mitchell provided the song's lead vocals, backed by Reggie Tsiboe, Frank Farian, Cathy Bartney, Madeleine Davis and Judy Cheeks. The single was intended to be included in the group's untitled seventh album, to be released in the fall of 1983. Due to a poor chart performance (No. 48 in the German charts), the single ultimately was not included in the album (which was completely reworked and not released until May 1984 as "Ten Thousand Lightyears").

"The Lion King" song.

In 1994 the Walt Disney Animation Studios animated movie "The Lion King" brought the phrase international recognition, featuring it prominently in the plot and devoting a song to it. A meerkat and a warthog, Timon and Pumbaa, teach Simba that he should forget his troubled past and live in the present. The song was written by Elton John (music) and Tim Rice (lyrics), who found the term in a Swahili phrasebook. It was nominated for Best Original Song at the 1995 Academy Awards, and was later ranked the 99th best song in movie history by the American Film Institute on a list of 100.

"Hakuna-matata" () is a Swahili language phrase from East Africa, meaning "no trouble" or "no worries" (literally "hakuna": "there is no/there are no"; "matata": "worries".) The phrase was used in the 1994 Disney animated film "The Lion King" and its 2019 remake (which feature a song named after the phrase), in which it is translated as "no worries". The song is often heard at resorts, hotels, and other places appealing to the tourist trade.

Hakuna matata est une devise issue de l'expression swahilie "Hakuna matatizo", signifiant « il n'y a pas de problème ». L'expression s'est d'abord fait connaître dans les pays occidentaux en 1983, avec la reprise, par Boney M., de la chanson "Jambo Bwana" (« Bonjour Monsieur ») du groupe kényan, sortie l'année précédente et qui reprend la phrase "« Hakuna matata »" dans son refrain. Elle a ensuite connu une nouvelle popularité avec le film d'animation "Le Roi lion" en 1994.


Description.

The flame tetra reaches about in standard length. The rear half of the body is flame red while the area in front of the dorsal fin is silver crossed by two dark vertical bars. All the fins are red except for the pectoral fins, which are colourless. The tip of the anal fin on the male is black, while on the female the fins have less red colouration but darker tips of the pectoral fins.

Distribution, habitat and status.

The flame tetra is native to Southeast Brazil, where it occurs in coastal parts of Rio de Janeiro (Guanabara bay region, and Paraíba do Sul and Guandu River basins) and São Paulo (upper Tietê River basin). It lives in rivers and streams, generally preferring shallow (less than deep), slow-flowing sections with vegetation and a water temperature from.  The species has declined drastically, mainly because of habitat loss, pollution and introduced species (especially tilapia and black bass). Although sometimes reported as extinct in the wild, wild populations survive. In its small remaining distribution, it is common in the Tietê River basin (which possibly is not natural, but introduced) and rare elsewhere. The last confirmed record from Rio de Janeiro is from 1992. The species is listed as endangered in the Brazilian national red list. Today large numbers are bred in captivity and it is common in the aquarium trade. This includes some selectively-bred forms (such as golden, orange and albino) that differ from the original wild form.

Aquarium keeping and captive breeding.

"H. flammeus" is a peaceful schooling fish, and will generally do well in groups. "H. flammeus" has an omnivorous diet. The species will breed in captivity.

The flame tetra ("Hyphessobrycon flammeus"), also known as the red tetra or Rio tetra, is a small freshwater fish of the characin family Characidae. This tetra was first introduced as aquarium fish in 1920 by C. Bruening, Hamburg, Germany, and formally described in 1924 by Dr. George S. Myers. Today large numbers are bred in captivity and it is common in the aquarium trade, but the remaining wild population in Southeast Brazil is highly threatened.

Le Tétra de Rio (Hyphessobrycon flammeus), aussi appelé Tétra flamme, est une espèce de poissons de la famille des Characidae. En aquariophilie, c'est le poisson idéal pour le débutant. Joliment coloré, résistant et pacifique, il met en valeur n'importe quel aquarium planté.


Les Premiers Hommes dans la Lune (film, 1964)

Plot.

In 1964, the United Nations has launched a rocket flight to the Moon. A multi-national group of astronauts in the UN spacecraft land, believing themselves to be the first lunar explorers. However, they discover a Union Jack flag on the surface and a note mentioning Katherine Callender, which claims the Moon for Queen Victoria.  Attempting to trace Callender in the records office in Dymchurch in Kent, south-east England, the UN authorities discover that she has died, but that her husband Arnold Bedford is still living in a nursing home known as "The Limes". The home's staff do not let him watch television reports of the Moon expedition because, according to the matron, it "excites him". Bedford's repeated lunar claims are dismissed as senile delusion. The UN representatives question him about the Moon, and he tells them his story, which is then shown in flashback.  In 1899, Arnold Bedford lives in a romantic spot, Cherry Cottage, next to a canal lock in Dymchurch. His fiancée, Katherine Callender, known as Kate, arrives by car (driving herself) visiting the house for the first time. It is implied that Bedford is in financial difficulties as he has a letter for rent arrears. They meet a nearby neighbour, inventor Joseph Cavor, who wants to buy the cottage, in case his experiments damage the cottage. Kate agrees this on Bedfords behalf. Bedford starts spending much time at Cavor's house, where he has a large laboratory. There he has invented Cavorite, a substance that will let anything it is applied to or made of deflect the force of gravity. He plans to use it to travel to the Moon. Bedford gets deeds signed up in Kath's name selling the cottage to Cavor in exchange for £5000... it must be remembered that he is selling something he does not own!  Cavor tempts Bedford into his scheme by telling him there are nuggets of gold on the moon. He has already built a spherical spaceship in the greenhouse next to the cottage. The sphere is lined inside in green velvet and has electric lights. There is an explosion at Cavor's house just as Kate arrives at the cottage. This is caused by Cavors assistant, Gibbs, going to the pub instead of watching the boiler. He shows her deep sea diving suits intended to keep them alive on the moon. The production of Cavorite is increased. Kate brings things for the trip: gin and bitters, chickens and an elephant gun. But she gives Bedford an ultimatum: Cavorite or me. Back at the cottage Kate is served with a summons by a bailiff accompanied by a silent policeman, charged with selling a property she does not own. Bedford and Cavor are just about to leave when Kate angrily hammers on the outside wanting to know what he has done. They pull her inside as the sphere launches.  On the long journey they eat only sardines. It is not explained how they steer, but opening a blind causes the sphere to instead head for the sun. They crash land on the moon. The men don the diving suits and Kate is put in the air-tight compartment.  While exploring the lunar surface, Bedford and Cavor fall down a vertical shaft, where there is breathable air and discover an insectoid population, the Selenites, living beneath the surface. (Cavor coins this name for the creatures after the Greek goddess of the Moon, Selene). Bedford attacks a group of Selenites out of fear, killing several, despite Cavor's horrified protests. After escaping from them, the two men discover that their sphere, still containing Kate, has been dragged into the underground city.  They are then attacked by a giant caterpillar-like "Moon Bull" which pursues them until the Selenites are able to dispatch it with their rayguns. Cavor and Bedford see the city's power station, a perpetual motion machine powered by sunlight. The Selenites quickly learn English and interrogate Cavor, who believes they wish to exchange scientific knowledge. Cavor has a discussion with the "Grand Lunar", the ruling entity of the Selenites. Bedford makes the assumption that Cavor, and presumably all humanity, is actually on trial, and attempts to kill the Grand Lunar with an elephant gun but fails due to Cavor's interference. Running for their lives, Bedford manages to find their sphere, and he and Kate escape; Cavor voluntarily stays on the Moon.  Bedford flies the sphere up a vertical light shaft, shattering the window-like covering at the top, and returns to Earth. He concludes his story by mentioning that they came down in the sea off Zanzibar, and their sphere sank without trace, while he and Kate managed to swim ashore. Cavor's ultimate fate remained unknown to them.  In the present, Bedford, the UN party and newspaper reporters watch on television the latest events on the Moon, where the UN astronauts have broken into the Selenite city and find it deserted and decaying. The ruined city starts to crumble and collapse, forcing the astronauts to retreat hastily. Seconds later the city is completely destroyed. Bedford realizes that the Selenites must have succumbed to Cavor's common cold virus to which they had no immunity.

Production.

Development.

Harryhausen was planning on following "Jason and the Argonauts"(1963) with a version of H.G. Wells' 1904 novel "The Food of the Gods and How It Came to Earth" when he met with writer Nigel Kneale. Harryhausen had long wanted to film Wells' "First Men in the Moon" but producer Charles Schneer was not enthusiastic, in part due to worries about the film's period setting. Kneale thought it was an excellent idea however and he and Harryhausen managed to persuade Schneer to make it.  Schneer said Kneale "is a very dour, straightforward, serious classicist. He was recognized in England as being the contemporary science-fiction screenwriter. I hired him because we needed his technical expertise. Then, we superimposed on that what we thought audiences would appreciate."  Another writer was brought on to rework Kneale's script. According to Kneale: "They wanted to jazz it up, make it funnier than I had imagined." He says this inspired the casting of Lionel Jeffries.  Kneale said in the book, Judd's character "was a blundering creature and it seemed important to keep that". The writer says he knew that a country would get to the Moon relatively soon and discover there were no Selenites. This is why he added to the script that the Selenites were wiped out by a cold from the professor, an idea Kneale says he took from "The War of the Worlds".

Director.

This was the third collaboration between producer Charles Schneer and director Nathan Juran. Schneer said Juran "was an excellent man for what he did, but he wasn't an actor's director. Many of our actors were used to more help from a director than he gave them. They felt a little adrift when they were expected to get on with their work without any great directorial assist. Jerry wasn't very patient with actors. He couldn't tolerate actors who wanted to know what their character's motivation was. He wanted to get on with the job he was hired to do."

Casting.

Schneer cast Judd off the back of his performance in "The Day the Earth Caught Fire" (1961). Edward Judd was under contract to Columbia Pictures. "I had never done anything like that at the time, so I thought it would be fun", Judd said. "Since Lionel was already a great chum of mine I knew we would have laughs on the set".  Martha Hyer's character was not in original drafts of scripts but introduced later.

Designs.

Ray Harryhausen used blueprints from NASA for the UN's lunar lander while designing sets.  The sculptor Bryan Kneale constructed the Selenites from Harryhausen's designs.

Spacesuits used.

Two types of space suits are featured in the film. During the story's main events, which take place in the 1890s, the film's Victorian-era astronauts are outfitted in space suits adapted from deep sea diving suits. Each is fitted with a 1960s-type aqualung cylinder worn as a backpack. Their space suits are neither pressurized nor heated or cooled, and they do not wear protective gloves in the vacuum of space and extreme cold and heat found on the lunar surface. There is an important technical issue with the heating and cooling provided: Using rubber-lined diving suits on the Moon is impractical due to the brittleness of natural rubber once it is exposed to a vacuum.  Cavor and Bedford have no radio communication and must make their space helmets touch in order to be able to talk with one another in the Moon's vacuum (the filmmakers violate this rule several times). It is not made clear whether the Selenites have radio. On Earth, the history of radio was only just beginning when the film's 1890s-set events were unfolding. Wireless communication from the stranded Cavor within the Moon appears later in Wells' novel.  The spacesuit type worn by the UN Astronauts in the film is actually the Windak high-altitude pressure suit, developed for the Royal Air Force, each fitted with a 1960s-type aqualung cylinder worn as a backpack. These pressure suits would also be used in two "Doctor Who" stories: William Hartnell's final story "The Tenth Planet" and the Patrick Troughton-era "The Wheel in Space". They also appear in the original "Star Wars" trilogy as the costumes for Bossk and Bo Shek.

Shooting.

Filming started on 1 October 1963.  Schneer convinced Harryhausen the movie's commercial prospects would be improved if it was shot in Panavision. "Ray was terrified of Panavision," said the producer. "All I had to do was suggest something different to him, and he would get nervous. "  "After you got past the first couple of reels, it was a funny film", said Juran. "Lionel was a swell actor. I liked him very much. His performance added immeasurably to the picture's entertainment value. He played it tongue-in-cheek but being such a good comic actor he controlled himself and never went too far. He made a great team with Edward Judd. Their personalities, one against the other, were just perfect".  "It was fun to do but it was bloody hard work," said Judd. "Lionel called it 'acting with chalk marks' because we were pointing at things that weren't there and dealing with blue backing and traveling mattes".  Harryhausen would explain to the actors what the creatures would eventually look like just before they shot scenes involving them.  "Lionel and I didn't like Jerry's working methods too much," said Judd. "He was more of a technician than an actor's director. We always thought of him as an art director, which of course he had been".

Reception.

Critical reception.

Among contemporary reviews, "Variety" wrote, "Ray Harryhausen and his special effects men have another high old time in this piece of science-fiction hokum filmed in Dynamation", adding that "Wells' novel and has been neatly updated", and concluding that "The three principals play second fiddle to the special effects and art work, which are impressive in color, construction and animation".  However, "The New York Times" wrote, "Only the most indulgent youngsters should derive much stimulation - let alone fun - from the tedious, heavyhanded science-fiction vehicle that arrived yesterday from England".  "The Guardian" called it "good of its type".  "TV Guide" called it "An enjoyable science fiction film". and "Blu-ray.com" highly recommended the film as "a fun and exciting viewing experience".

Box-office.

The film was a box-office disappointment. Harryhausen felt this was due to the inclusion of too much comedy.  Schneer said he preferred the film to "Jason and the Argonauts" because "it was set in the Victorian era, whereas "Jason" took place in a much further removed period of history. Also, I thought the humor in it was delicious, whereas there wasn't much humor in "Jason"." The producer says Harryhausen felt "fantasy film fans are dead serious about these pictures and have no sense of humor. So, who am I to quarrel with him?"  Kneale says the final movie was "all right. It could have been better if it had been a bit less farcical; that would have been more imaginative."

Legacy.

Schneer says that when the real Moon landing happened, NASA "had no footage showing the space capsule separating from the'mother ship' and landing on the Moon's surface. All they had were shots of Neil Armstrong walking around." NASA went to Columbia Pictures and used the opening sequence of "First Men on the Moon". "They used those portions of it which were applicable to their needs," said the producer.  Following the movie, Harryhausen and Schneer did not work together for five years.

First Men in the Moon is a 1964 British Technicolor science fiction film, produced by Charles H. Schneer, directed by Nathan Juran, and starring Edward Judd, Martha Hyer and Lionel Jeffries. The film, distributed by Columbia Pictures, is an adaptation by screenwriter Nigel Kneale of H. G. Wells' 1901 novel "The First Men in the Moon".

Les Premiers Hommes dans la Lune () est un film britannique réalisé par Nathan Juran, sorti en 1964. La technique de l'animation en volume est utilisée dans ce film (comme dans tous les films où Ray Harryhausen a officié).


Life.

Agostino Carracci was born in Bologna as the son of a tailor. He was the elder brother of Annibale Carracci and the cousin of Ludovico Carracci. He initially trained as a goldsmith. He later studied painting, first with Prospero Fontana, who had been Lodovico's master, and later with Bartolomeo Passarotti. He traveled to Parma to study the works of Correggio. Accompanied by his brother Annibale, he spent a long time in Venice, where he trained as an engraver under the renowned Cornelis Cort. Starting from 1574 he worked as a reproductive engraver, copying works of 16th century masters such as Federico Barocci, Tintoretto, Antonio Campi, Veronese and Correggio. He also produced some original prints, including two etchings.  He traveled to Venice (1582, 1587–1589) and Parma (1586–1587). Together with Annibale and Ludovico he worked in Bologna on the fresco cycles in Palazzo Fava ("Histories of Jason and Medea", 1584) and Palazzo Magnani ("Histories of Romulus", 1590–1592). In 1592 he also painted the "Communion of St. Jerome", now in the Pinacoteca di Bologna and considered his masterwork. In 1620, Giovanni Lanfranco, a pupil of the Carracci, famously accused another Carracci student, Domenichino, of plagiarizing this painting. From 1586 is his altarpiece of the "Madonna with Child and Saints", in the National Gallery of Parma. In 1598 Carracci joined his brother Annibale in Rome, to collaborate on the decoration of the Gallery in Palazzo Farnese. From 1598–1600 is a "triple Portrait", now in Naples, an example of genre painting. In 1600 he was called to Parma by Duke Ranuccio I Farnese to begin the decoration of the Palazzo del Giardino, but he died before it was finished.  Agostino's son Antonio Carracci was also a painter, and attempted to compete with his father's Academy.  An engraving by Agostino Carraci after the painting "Love in the Golden Age" by the 16th-century Flemish painter Paolo Fiammingo was the inspiration for Matisse's "Le bonheur de vivre" (Joy of Life).

See also.

The Carracci

Agostino Carracci (or Caracci) (16 August 1557 – 22 March 1602) was an Italian painter, printmaker, tapestry designer, and art teacher. He was, together with his brother, Annibale Carracci, and cousin, Ludovico Carracci, one of the founders of the Accademia degli Incamminati (Academy of the Progressives) in Bologna. This teaching academy promoted the Carracci emphasized drawing from life. It promoted progressive tendencies in art and was a reaction to the Mannerist distortion of anatomy and space. The academy helped propel painters of the School of Bologna to prominence.

Agostino Carracci, dit aussi Caracci ou Augustin Carrache, né à Bologne le et mort à Parme le, est un peintre et graveur italien de la Renaissance.


Origins.

There is evidence that soldering was employed as early as 5,000 years ago in Mesopotamia. Soldering and brazing are thought to have originated very early in

Applications.

Soldering is used in plumbing, electronics, and metalwork from flashing to jewellery and musical instruments. Soldering provides reasonably permanent but reversible connections between copper pipes in plumbing systems as well as joints in sheet metal objects such as food cans, roof flashing, rain gutters and automobile radiators.  Jewelry components, machine tools and some refrigeration and plumbing components are often assembled and repaired by the higher temperature silver soldering process. Small mechanical

Solders.

Soldering filler materials are available in many different alloys for differing applications. In electronics assembly, the eutectic alloy with 63% tin and 37% lead (or 60/40, which is almost identical in melting point) has been the alloy of choice. Other alloys are used for plumbing, mechanical assembly, and other applications. Some examples of soft-solder are tin-lead for general purposes, tin-zinc for joining aluminium, lead-silver for strength at higher than room temperature, cadmium-silver for strength at high temperatures, zinc-aluminium for aluminium and corrosion resistance, and tin-silver and tin-bismuth for electronics.  A eutectic formulation has advantages when applied to soldering: the liquidus and solidus temperatures are the same, so there is no plastic phase, and it has the lowest possible melting point. Having the lowest possible melting point minimizes heat stress on electronic components during soldering. And, having no plastic phase allows for quicker wetting as the solder heats up, and quicker setup as the solder cools. A non-eutectic formulation

Flux.

The purpose of flux is to facilitate the soldering process. One of the obstacles to a successful solder joint is an impurity at the site of the joint, for example, dirt, oil or oxidation. The impurities can be removed by mechanical cleaning or by chemical means, but the elevated temperatures required to melt the filler metal (the solder) encourages the work piece (and the solder) to re-oxidize. This effect is accelerated as the soldering temperatures increase and can completely prevent the solder from joining to the workpiece. One of the earliest forms of flux was charcoal, which acts as a reducing agent and helps prevent oxidation during the soldering process. Some fluxes go beyond the simple prevention of oxidation and also provide some form of chemical

Processes.

There are three forms of soldering, each requiring progressively higher temperatures and producing an increasingly stronger joint strength:  The alloy of the filler metal for each type of soldering can be adjusted to modify the melting temperature of the filler. Soldering differs from gluing significantly in that the filler metals directly bond with the surfaces of the workpieces at the junction to form an electrically conductive gas- and liquid-tight bond.  Soft soldering is characterized by having a melting point of the filler metal below approximately, whereas silver soldering and brazing use higher temperatures, typically requiring a flame or carbon arc torch to achieve the melting of the filler. Soft solder filler metals are typically alloys (often containing lead) that have liquidus temperatures below.  In this soldering process, heat is applied to the parts to be joined, causing the solder to melt and to bond to the workpieces in a surface alloying process called wetting. In stranded wire, the solder is drawn up into the wire between the strands by capillary action in a process called 'wicking'. Capillary action also takes place when the workpieces are very close together or touching. The joint's tensile strength is dependent on the filler metal used; in electrical soldering little tensile strength comes from the added solder which is why it is advised that wires be twisted or folded together before soldering to provide some mechanical strength for a joint. A good solder joint produces an electrically-conductive, water- and gas-tight join.  Each type of solder offers advantages and disadvantages. Soft solder is so called because of the soft lead that is its primary ingredient. Soft soldering uses the lowest temperatures (and so thermally stresses components the least) but does not make a strong joint and is unsuitable for mechanical load-bearing applications. It is also unsuitable for high-temperature applications as it loses strength, and eventually melts. Silver soldering, as used by jewelers, machinists and in some plumbing applications, requires the use of a torch or other high-temperature source, and is much stronger than soft soldering. Brazing provides the strongest of the non-welded joints but also requires the hottest temperatures to melt the filler metal, requiring a torch or other high temperature source and darkened goggles to protect the eyes from the bright light produced by the white-hot work. It is often used to repair cast-iron objects, wrought-iron furniture, etc.  Soldering operations can be performed with hand tools, one joint at a time, or "en masse" on a production line. Hand soldering is typically performed with a soldering iron, soldering gun, or a torch, or occasionally a hot-air pencil. Sheetmetal work was traditionally done with "soldering coppers" directly heated by a flame, with sufficient stored heat in the mass of the soldering copper to complete a joint; gas torches (e.g. butane or propane) or electrically-heated soldering irons are more convenient. All soldered joints require the same elements of cleaning of the metal parts to be joined, fitting up the joint, heating the parts, applying flux, applying the filler, removing heat and holding the assembly still until the filler metal has completely solidified. Depending on the nature of flux material used and the application, cleaning of the joint may be required after it has cooled.  Each solder alloy has characteristics that work best for certain applications, notably strength and conductivity, and each type of solder and alloy has different melting temperatures. The term "silver solder" denotes the type of solder that is used. Some soft solders are "silver-bearing" alloys used to solder silver-plated items. Lead-based solders should not be used on precious metals because the lead dissolves the metal and disfigures it.

Solderability.

The solderability of a substrate is a measure of

Desoldering and resoldering.

Used solder contains some of the dissolved base metals and is unsuitable for reuse in making new joints. Once the solder's capacity for the base metal has been achieved it will no longer properly bond with the base metal, usually resulting in a brittle cold solder joint with a crystalline appearance.  It is good practice to remove solder from a joint prior to resoldering—desoldering braids or vacuum desoldering equipment (solder suckers)

Lead-free electronic soldering.

More recently environmental legislation has specifically targeted the wide use of lead in the electronics industry. The RoHS directives in Europe required many new electronic circuit boards to be lead-free by 1 July 2006, mostly in the consumer goods industry, but in some others as well. In Japan lead was phased out prior to legislation by manufacturers due to the additional expense in recycling products containing lead. However, even without the presence of lead, soldering can release fumes that are harmful and/or toxic to humans. It is highly recommended to use a device that can remove the fumes from the work area either by ventilating outside or filtering the air.  Lead free soldering

Soldering defects.

In the joining of copper tube, failure to properly heat and fill a joint may lead to a 'void' being formed. This is usually a result of improper placement of the flame. If the heat of the flame is not directed at the back of the fitting cup, and the solder wire applied degrees opposite the flame, then solder will quickly fill the opening of the fitting, trapping some flux inside the joint. This bubble of trapped flux is the void; an area inside a soldered joint where solder is unable to completely fill the fittings' cup, because flux has become sealed inside the joint, preventing solder from occupying that space.

Electronics.

Various problems may arise in the soldering process which lead to joints which are nonfunctional either immediately or after a period of use.  The most common defect when hand-soldering results from the parts being joined not exceeding the solder's liquidus temperature, resulting in a "cold solder" joint. This is usually the result of the soldering iron being used to heat the solder directly, rather than the parts themselves. Properly done, the iron heats the parts to be connected, which in turn melt the solder, guaranteeing adequate heat in the joined parts

Tools.

In principle any type of soldering tool can carry out any work using solder at temperatures it can generate. In practice different tools are more suitable for different applications.  Hand-soldering tools widely used for electronics work include the electric soldering iron, which can be fitted with a variety of tips ranging from blunt to very fine, to chisel heads for hot-cutting plastics rather than soldering. The simplest irons do not have temperature regulation; small irons rapidly cool when used to solder to, say, a metal chassis, while large irons have tips too cumbersome for working on PCBs and similar fine work. Temperature-controlled irons have a reserve of power and can maintain temperature over a wide range of work. The soldering gun heats faster but has a larger and heavier body. Gas-powered irons using a catalytic tip to heat a bit, without flame, are used for portable applications. Hot-air guns and pencils allow rework of component packages which cannot easily be performed with electric irons and guns.  For non-electronic applications soldering torches use a flame rather than a soldering tip to heat solder. Soldering torches are often powered by butane and are available in sizes ranging from very small butane/oxygen units suitable for very fine but high-temperature jewelry work, to full-size oxy-fuel torches suitable for much larger work such as copper piping. Common multipurpose propane torches, the same kind used for heat-stripping paint and thawing pipes, can be used for soldering pipes and other fairly large objects either with or without a soldering tip attachment; pipes are generally soldered with a torch by directly applying the open flame.  A soldering copper is a tool with a large copper head and a long handle which is heated in a blacksmith's forge fire and used to apply heat to sheet metal for soldering. Typical soldering coppers have heads weighing between one and four pounds. The head provides a large thermal mass to store enough heat for soldering large areas before needing re-heating in the fire; the larger the head, the longer the working time. Historically, soldering coppers were standard tools used in auto bodywork, although body solder has been mostly superseded by spot welding for mechanical connection, and non-metallic fillers for contouring.  Toaster ovens and hand held infrared lights have been used by hobbyists to replicate production soldering processes on a much smaller scale.  Bristle brushes are usually used to apply plumbing paste flux. For electronic work, flux-core solder is generally used, but additional flux may be used from a flux pen or dispensed from a small bottle with a syringe-like needle.  Wire brush, wire wool and emery cloth are commonly used to prepare plumbing joints for connection. Electronic joints are usually made between surfaces that have been tinned and rarely require mechanical cleaning, though tarnished component leads and copper traces with a dark layer of oxide passivation (due to aging), as on a new prototyping board that has been on the shelf for about a year or more, may need to be mechanically cleaned.  Some fluxes for electronics are designed to be stable and inactive when cool and do not need to be cleaned off, though they still can be if desired, while other fluxes are acidic and must be removed after soldering to prevent corrosion of the circuits. For PCB assembly and rework, either an alcohol or acetone is commonly used with cotton swabs or bristle brushes to remove flux residue after soldering. A heavy rag is usually used to remove flux from a plumbing joint before it cools and hardens. A fiberglass brush can also be used.  A heat sink, such as a crocodile clip, can be used to prevent damaging heat-sensitive components while hand-soldering. The heat sink limits the temperature of the component body by absorbing and dissipating heat (reducing the thermal resistance between the component and the air), while the thermal resistance of the leads maintains the temperature difference between the part of the leads being soldered and the component body so that the leads become hot enough to melt the solder while the component body remains cooler. When soldering pipes closely connected to valves such as in refrigeration systems it may be necessary to protect the valve from heat that could damage rubber or plastic components within, in this case a wet cloth wrapped around the valve can often sink sufficient heat through the boiling of the water to protect the valve.  During WW2 and for some time afterwards SOE forces used small pyrotechnic self-soldering joints to make connections for the remote detonation of demolition and sabotage explosives. These consisted of a small copper tube partially filled with solder and a slow-burning pyrotechnic composition wrapped around the tube. The wires to be joined would be inserted into the tube and a small blob of ignition compound allowed the device to be struck like a match to ignite the pyrotechnic and heat the tube for long enough to melt the solder and make the joint.

Soldering (AmE:, BrE: ) is a process in which two or more items are joined together by melting and putting a filler metal (solder) into the joint, the filler metal having a lower melting point than the adjoining metal. Unlike welding, soldering does not involve melting the work pieces. In brazing, the work piece metal also does not melt, but the filler metal is one that melts at a higher temperature than in soldering. In the past, nearly all solders contained lead, but environmental and health concerns have increasingly dictated use of lead-free alloys for electronics and plumbing purposes.

Le brasage des métaux est un procédé d'assemblage permanent qui établit une liaison métallique entre les pièces réunies. Contrairement au soudage, il n'y a pas fusion des bords assemblés. Selon les cas il peut y avoir ou non utilisation d'un. Le mécanisme du brasage est la diffusion/migration atomique de part et d'autre de l'interface solide/solide dans le cas d'un brasage sans métal d'apport et de l'interface solide/liquide/solide lorsqu'un métal d'apport est utilisé, processus obtenu par action calorique et/ou mécanique.


Species.

The following 15 species are currently accepted in "Saxicola":  Formerly included in the genus "Saxicola", but now treated in a separate genus:

Taxonomy.

The genus was introduced by the German naturalist Johann Matthäus Bechstein in 1802. The type species was subsequently designated as the European stonechat. The name "Saxicola" is from Latin "saxum", "saxi" "stone" and "-cola" "dweller".  The genus was formerly included in the thrush family Turdidae, but as with several other related genera, has now been shown to be correctly classified in the Old World flycatcher family Muscicapidae, in which it is most closely related to the genera "Oenanthe" (wheatears) and "Campicoloides".  Genetic and behavioural evidence has also resulted in several new species being accepted in the genus in recent years, most notably the splitting of the former broad "species" common stonechat "Saxicola torquatus" into five species, a change now widely though not yet universally accepted. With addition of mtDNA cytochrome "b" sequence and nDNA fingerprinting data, it was confirmed that not only the Fuerteventura and Réunion stonechats are distinct species, but that in addition, the African, Madagascan, European, Siberian and Stejneger's stonechats are also all separate species. Due to confusion of subspecies allocation, the name "S. torquatus" was briefly used for the European species, with the African stonechat being incorrectly listed as "S. axillaris".  Owing to misunderstandings of Latin syntax, several species have in the past been widely but incorrectly cited with feminine name endings (""S. torquata, S. maura, S. leucura, S. ferrea"", etc.).

Saxicola (Latin: "saxum", rock + "incola", dwelling in), the stonechats or chats, is a genus of 15 species of small passerine birds restricted to the Old World. They are insectivores occurring in open scrubland and grassland with scattered small shrubs.

Saxicola est un genre d'oiseaux de l'ordre des Passeriformes et de la famille des muscicapidés. Ses espèces sont appelées tariers et parfois traquets.


Subspecies.

Several subspecies are recognized by some authors:

Distribution.

This species is native to Europe:  "Arianta arbustorum" is introduced to North America, but is only known from Canada, where established populations are known from Newfoundland, New Brunswick, Ontario, and Prince Edward Island.  This species has not yet become established in the US, but it is considered to represent a potentially serious threat as a pest, an invasive species which could negatively affect agriculture, natural ecosystems, human health or commerce. Therefore, it has been suggested that this species be given top national quarantine significance in the USA.

Description.

The shell is usually brown with numerous pale yellowish rows of spots and usually with a brown band above the periphery, occasionally yellowish, reddish or with greenish hue, weakly striated and with fine spiral lines on the upper side. The shell has 5-5.5 convex whorls with deep suture. The last whorl is slightly descending near the aperture. The aperture is with prominent white lip inside. The apertural margin is reflected. Umbilicus is entirely covered by the reflected columellar margin.  The width of the shell is 18–25 mm. The height of the shell is 12–22 mm. Dimensions are locally variable.  The shell shape is globular in most present-day populations, but originally is believed to have been depressed in the Pleistocene, before lowlands were invaded and shells became globular, re-invading mountain regions except some isolated spots among glaciers.  The animal is usually black.

Life cycle.

"Arianta arbustorum" lives in forests and open habitats of any kind. It requires humidity. It lives also in disturbed habitats (not in Ireland where it is restricted to old native woodland). It may locally tolerate non-calcareous substrate, in north Scotland also on sandhills. In the Alps up to 2700 m, in Britain 1200 m, in Bulgaria 1500 m.  It feeds on green herbs, dead animals and faeces.  If snails hatched more than 50 m distant from each other, they are considered isolated since they would not move more than 25 m (neighbourhood area 32–50 m), usually they move about 7–12 m in a year, mostly along water currents. This species of snail makes and uses calcareous love darts during mating. Reproduction is usually after copulation, but self-fertilization is also possible. The size of the egg is 3.2 mm. Maturity is reached after 2–4 years. The maximum age up to 14 years.  "Angiostrongylus vasorum" has successfully experimentally infected this snail.

References.

This article incorporates public domain text from the reference.

Arianta arbustorum is a medium-sized species of land snail, sometimes known as the "copse snail", a terrestrial pulmonate gastropod mollusk in the family Helicidae.

Arianta arbustorum ou « Hélice des bois » est un escargot européen, qui est comme son nom le rappelle inféodé aux forêts, bois et bosquets. Il craint les milieux ouverts et non végétalisés.


Description.

"C. pubescens" varies from small to large in size, growing to 10 meters in height (33 ft). When cut, the bark tends to turn red. Leaves are elliptical to oblate and thin. The leaves have pubescent teeth that turn red when they are older, hence its nickname the red quinine tree. Its flowers form in large panicles. They are pink and fragrant, while in the Galapagos they are light pink.

Ecology.

"C. pubescens" has the widest distribution of all "Cinchona" species, with the native range spanning Costa Rica, Panama, Venezuela, Colombia, Ecuador, Peru, and Bolivia. In Ecuador it is distributed within an altitude from. It also grows well in volcanic soil with high nutrient levels.  C. pubescens is a resilient species that is able to recover from even extreme damage. If the tree is felled but the stump is left, it can grow back new stalks. If the bark is removed and the xylem is exposed to the elements, the tree will grow the bark back. The tree can even grow back if roots that are left in the ground are larger than 2 cm in diameter.  It reproduces rapidly and spreads its seeds via wind. It reaches maturity and begins seeding in 4 years. Growing at a rate of 1–2 m per year, it quickly reaches a tall height where it can shade out the rest of the native plants. Adult trees grow much slower than juveniles.

Invasive species.

It has become an invasive species where planted outside of its native range, especially on tropical climate islands such as the Galapagos, Hawaii, and Tahiti. In the Galapagos it has become a dominant species in the formerly shrub dominated Miconia and Fern-Sedge zones on Santa Cruz Island. It has been subject to control in the Galapagos National Park to reduce its impacts using a variety of methods. However, controlling it over its total range on Santa Cruz island would cost US$1.65 million according to research done through the Charles Darwin Foundation.  According to Jäger "et al." 2007, the species richness on Santa Cruz Island, Galapagos Islands has declined by 33% in the Miconia Zone and 10% in the Fern-Sedge Zone since the introduction "C. pubescens". It is also invasive in Hawaii, on Maui and the Big Island "C. pubescens" was first introduced to these to be cultivated for quinine harvesting.

Control Strategies.

There are currently two strategies for removal of "C. pubescens". They include a physical method and a chemical method. The physical method involves manually felling adult trees and fully removing the stumps. Samplings must be pulled out of the soil. The chemical method uses herbicides diluted in water and sprayed on hack marks on the bark. Buddenhagen "et al." tried this at the Galapagos Island National Park using a mixture of picloram and metsulfuron. This technique has been recommended to be performed in Tahiti and Hawaii since it is an invasive there as well.  Buddenhagen "et al." 2004 analyzed data using six different herbicide methods from 1999-2002 with a different trial each year: picloram salt, triclopyr ester, triclopyr salt, glyphosate, diesel fuel, and picloram and metsulfuron. The herbicide was sprayed onto the trees where they were hacked with machetes. In the first trial, triclopyr ester could control "C. pubescens" with 77% chance of the trees dying. In the second trial, a picloram and metsulfuron solution was 100% successful in concentrations greater than 4% solution. In the third trial, picloram- metsulfuron solution of 10% concentrations or higher was successful in eradicating the tree.

Cinchona pubescens, also known as red cinchona and quina (Quechua) ( "Cascarilla, cinchona"; "quina-do-amazonas, quineira"), is native to Central and South America. It is known as a medicinal plant for its bark's high quinine content- and has similar uses to "Cinchona officinalis" in the production of quinine, most famously used for treatment of malaria.

Le quinquina rouge "(Cinchona pubescens)" est un petit arbre sempervirent de la famille des Rubiacées, originaire de la Cordillère des Andes et d'Amérique centrale et dont l'écorce est riche en quinine.