Principles and juridical limits to human embryo research]

This work intends to provide a wide scope of the legal situation in Brazil referred to Human Embryos and how it has been developed through the 20th century. Across the last century, the human being got the possibility of making genetic experiments with human embryos. Our main goal is to assume the future responsibility of these actions through a juridical and ethical point of view.     

In vitro changes in human spermatozoa exposed to gastric juice: laboratory findings as a support for forensic practice

Samples of complete human semen were incubated in gastric juice for different time periods at 37 degrees C, and by simulating the post-mortem temperature decrease of the human body. The changes in the spermatozoa were similar in both experiments. Short incubation specimens were examined directly with interference contrast microscopy and showed an almost immediate immobilization of spermatozoa when they were brought in contact with gastric juice. Specimens with longer incubation periods were stained with alcalic fuchsine and examined by immersion microscopy. There was a morphologically stable plateau for the heads of the spermatozoa for up to 6 h of incubation. The tails disappeared progressively in the first 45 min. After more than 6 h of incubation a progressive swelling and lysis of the heads was observed. Spermatozoa could be recognized for up to 7 days of incubation.     

Child witness statement quality

Use of general questions in child witness interviews often limits the completeness of young children's recall. In this study experienced professionals interviewed 5–6 year olds and 8–9 year olds “as they would normally” about live events witnessed by the children. Interviewers' spontaneous use of general and specific questions was assessed, as were the effects of these question types on the children's recall. A main result was that the younger children would frequently fail to answer general questions but would then provide information relevant to these same questions later in the interview. Use of specific questions in these relatively naturalistic interviews did not necessarily improve the overall completeness of younger children's recall, contrary to some previous findings, although, in line with previous findings, such questioning reduced overall accuracy rates. These results highlighted the scale of the problem of “omission errors” in young children's recall. Implications for the use of general questions by professionals who interview child witnesses are discussed.     

Are people who cooperate ‘rational altruists’?

In experimental games, as in natural situations, people are often observed acting to the benefit of others even at considerable cost to themselves. Such behavior is contrary to the assumption of selfish behavior, but it is not necessarily contrary to the assumption of rationality: People cooperating under these circumstances could be ‘rational altruists’ who base their decision on the magnitude of the external benefit, as well as on the costs to themselves. We test that proposition using a prisoners' dilemma experimental paradigm. If it is correct, we should observe higher levels of cooperation as the external benefit in such games increases. But we do not — whether external benefit is measured in terms of number of individuals benefiting from a cooperative choice or the total dollar benefit produced. Cooperation must be explained otherwise.     

An improved method for subtyping Pi in old bloodstains.

Immunofixation procedures were used for detecting alpha-1 antitrypsin protease inhibitor (Pi) phenotypes in bloodstains. Neuraminidase elution of bloodstains, together with isoelectric focusing, immunofixation, and silver staining techniques, makes possible Pi subtyping in old bloodstains. No extra bands appear when the storage time is no longer than three months.