Filter by Topic
Filter by Format
"Reproductive Options for HIV-Serodiscordant Couples” (2006) by Pablo Barreiro, Ann Duerr, Karen Beckerman, and Vincent Soriano
In July 2006, scientist Pablo Barreiro and colleagues published “Reproduction Options for HIV-Serodiscordant Couples,” in which they recommended methods for human immunodeficiency virus, or HIV, serodiscordant couples to procreate. An HIV-serodiscordant couple is one in which one partner is HIV-positive, meaning they carry HIV, and the other is HIV-negative, meaning they do not carry the virus. HIV is a virus that can spread by sexual contact and it attacks the immune system, causing a person with the virus to have weakened responses to illnesses.
Regeneration is a fascinating phenomenon. The fact that many organisms have the capacity to regenerate lost parts and even remake complete copies of themselves is difficult to fathom; so difficult, in fact, that for a very long time people were reluctant to believe regeneration actually took place. It seemed unbelievable that some organisms could re-grow lost limbs, organs, and other body parts. If only we could do the same!
Sprayed extensively by the US military in Vietnam, Agent Orange contained a dioxin contaminant later found to be toxic to humans. Despite reports by Vietnamese citizens and Vietnam War veterans of increased rates of stillbirths and birth defects in their children, studies in the 1980s showed conflicting evidence for an association between the two. In 1996, the US National Academy of Sciences reported that there was evidence that suggested dioxin and Agent Orange exposure caused spina bifida, a birth defect in which the spinal cord develops improperly.
"Altruism and the Origin of the Worker Caste" from The Ants (1990), by Bert Hölldobler and Edward Osborne Wilson
In 'Altruism and the Origin of the Worker Caste,' Bert Hölldobler and Edward Osborne Wilson explore the evolutionary origins of worker ants. 'Altruism and the Origin of the Worker Caste' is the fourth chapter of Hölldobler and Wilson's book, The Ants, which was published by The Belknap Press of Harvard University in Cambridge, Massachusetts, in 1990. In 'Altruism and the Origin of the Worker Caste,' Hölldobler and Wilson evaluate various explanations for how a non-reproductive caste of ant evolved.
Homology is a central concept of comparative and evolutionary biology, referring to the presence of the same bodily parts (e.g., morphological structures) in different species. The existence of homologies is explained by common ancestry, and according to modern definitions of homology, two structures in different species are homologous if they are derived from the same structure in the common ancestor.
Format: Essays and Theses