Bronze is formed as a result of copper and tin bonding in what is called a c. Metallic bond or Enlace metálico.
A metallic bond:
- Joins the atoms of a metal to that of another metal
- Are quite strong
- Lead to the formation on materials that have high melting points and high boiling points.
The bonding of copper and tin is therefore a metallic bond as both of these are metals. Bronze is therefore a product of metallic bonding which is why it has a high melting point and a high boiling point.
In conclusion, bronze is made from metallic bonding.
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The Tuskegee Study of Untreated Syphilis in the African American Male is the longest nontherapeutic experiment on human beings in medical history, as noted by Arthur L. Caplan (1992). Begun in 1932 by the United States Public Health Service (USPHS), the study was purportedly designed to determine the natural course of untreated latent syphilis in some 400 African American men in Tuskegee, Macon County, Alabama. The research subjects, all of whom had syphilis when they were enrolled in the study-contrary to the “urban myth” that holds “black men in Alabama were injected with the virus that causes syphilis” (Walker, 1992)-were matched against 200 uninfected subjects who served as a control group.
The subjects were recruited with misleading promises of “special free treatment,” which were actually spinal taps done without anesthesia to study the neurological effects of syphilis, and they were enrolled without their informed consent.
The subjects received heavy metals therapy, standard treatment in 1932, but were denied antibiotic therapy when it became clear in the 1940s that penicillin was a safe and effective treatment for the disease. When penicillin became widely available by the early 1950s as the preferred treatment for syphilis, this therapy was again withheld. On several occasions, the USPHS actually sought to prevent treatment.
The first published report of the study appeared in 1936, with subsequent papers issued every four to six years until the early 1970s. In l969, a committee at the federally operated Center for Disease Control decided the study should continue. Only in 1972, when accounts of the study first appeared in the national press, did the Department of Health, Education and Welfare (HEW) halt the experiment.
At that time, 74 of the test subjects were still alive; at least 28, but perhaps more than 100, had died directly from advanced syphilis. An investigatory panel appointed by HEW in August 1972 found the study “ethically unjustified” and argued that penicillin should have been provided to the men. As a result, the National Research Act, passed in 1974, mandated that all federally funded proposed research with human subjects be approved by an institutional review board (IRB). By 1992, final payments of approximately $40,000 were made to survivors under an agreement settling the class action lawsuit brought on behalf of the Tuskegee Study subjects. President Clinton publicly apologized on behalf of the federal government to the handful of study survivors in April 1997.
Several major ethical issues involving human research subjects need to be studied further. The first major ethical issue to be considered is informed consent, which refers to telling potential research participants about all aspects of the research that might reasonably influence their decision to participate. A major unresolved concern is exactly how far researchers’ obligations extend to research subjects. Another concern has to do with the possibility that a person might feel pressured to agree or might not understand precisely what he or she is agreeing to. The investigators took advantage of a deprived socioeconomic situation in which the participants had experienced low levels of care. The contacts were with doctors and nurses who were seen as authority figures.
Nazis anti-semitisitm the Holocaust
Answer:
The right answer is D.
Explanation:
The lure of getting free land or inexpensive lands plus government policies to encourage settlement and colonization, provided a powerful stimulus to migration to the West along the 19th century in the United States, both before and after the Mexican-American War of 1846-1848.
