What's scene and not seen: Influences of movement and task upon what we see

Studies concerning the processing of natural scenes using eye movement equipment have revealed that observers retain surprisingly little information from one fixation to the next. Other studies, in which fixation remained constant while elements within the scene were changed, have shown that, even without refixation, objects within a scene are surprisingly poorly represented. Although this effect has been studied in some detail in static scenes, there has been relatively little work on scenes as we would normally experience them, namely dynamic and ever changing. This paper describes a comparable form of change blindness in dynamic scenes, in which detection is performed in the presence of simulated observer motion. The study also describes how change blindness is affected by the manner in which the observer interacts with the environment, by comparing detection performance of an observer as the passenger or driver of a car. The experiments show that observer motion reduces the detection of orientation and location changes, and that the task of driving causes a concentration of object analysis on or near the line of motion, relative to passive viewing of the same scene.

Goal setting among adolescents: A comparison of delinquent, at risk, and not-at-risk youth

A series of studies was conducted to compare group differences in the goal orientations of delinquent, at-risk, and not-at-risk adolescents. An Importance of Goals Scale was developed by examining the item responses of 230 high school students and validated by administering the revised scale to 80 delinquent, 90 at-risk, and 90 not-at-risk adolescents. Results identified differences in the importance attributed to different goals by the 3 groups. Delinquent and at-risk adolescents attached significantly more importance to goals associated with developing a social image (e.g., delinquency, freedom-autonomy), whereas not-at-risk adolescents were more concerned with goals associated with an academic image (e.g., educational, interpersonal). Results are discussed in terms of their implications for school achievement, peer relations, and future life paths.

Microcin J25 has a threaded sidechain-to-backbone ring structure and not a head-to-tail cyclized backbone

Microcin J25 is a 21 amino acid bacterial peptide that has potent antibacterial activity against Gram-negative bacteria, resulting from its interaction with RNA polymerase. The peptide was previously proposed to have a head-to-tail cyclized peptide backbone and a tight globular structure (Blond, A., Peduzzi, J., Goulard, C., Chiuchiolo, M. J., Barthelemy, M., Prigent, Y., Salomon, R. A., Farias, R. N., Moreno, F. & Rebuffat, S. Eur. J. Biochem. 1999, 259, 747-755). It exhibits remarkable thermal stability for a peptide of its size lacking disulfide bonds and in part this was previously proposed to derive from its macrocyclic structure. We show here that in fact the peptide does not have a head-to-tail cyclic structure but rather a side chain to backbone cyclization between Glu8 and the N-terminus. This creates an embedded ring that is threaded by the C-terminal tail of the molecule, forming a noose-like feature. The three-dimensional structure deduced from NMR data suggests that slippage of the noose is prevented by two aromatic residues flanking the embedded ring. Unthreading does not occur even when the molecule is enzymatically digested with thermolysin. The new structural interpretation fully accounts for previously reported NMR and biophysical data and is consistent with the remarkable stability of this potent antimicrobial peptide.

Family structure and age at menarche: A children-of-twins approach

Girls who grow up in households with an unrelated adult male reach menarche earlier than peers, a finding hypothesized to be an evolutionary strategy for families under stress. The authors tested the alternative hypothesis that nonrandom selection into stepfathering due to shared environmental and/or genetic predispositions creates a spurious relation between stepfathering and early menarche. Using the unique controls for genetic and shared environmental experiences offered by the children-of-twins design, the authors found that cousins discordant for stepfathering did not differ in age of menarche. Moreover, controlling for mother's age of menarche eliminated differences in menarcheal age associated with stepfathering in unrelated girls. These findings strongly suggest selection, and not causation, accounts for the relationship between stepfathering and early menarche.

Should the health community promote smokeless tobacco (snus) as a harm reduction measure?

Background to the debate: The tobacco control community is divided on whether or not to inform the public that using oral, smokeless tobacco (Swedish snus) is less hazardous to health than smoking tobacco. Proponents of 'harm reduction' point to the Swedish experience. Snus seems to be widely used as an alternative to cigarettes in Sweden, say these proponents, contributing to the low overall prevalence of smoking and smoking-related disease. Harm reduction proponents thus argue that the health community should actively inform inveterate cigarette smokers of the benefits of switching to snus. However, critics of harm reduction say that snus has its own risks, that no form of tobacco should ever be promoted, and that Sweden’s experience is likely to be specific to that culture and not transferable to other settings. Critics also remain deeply suspicious that the tobacco industry will use snus marketing as a 'gateway' to promote cigarettes. In the interests of promoting debate, the authors (who are collaborators on a research project on the future of tobacco control) have agreed to outline the strongest arguments for and against promoting Swedish snus as a form of harm reduction.

Who does not gain weight? Prevalence and predictors of weight maintenance in young women

OBJECTIVE: To investigate the prevalence and predictors of weight maintenance over time in a large sample of young Australian women. DESIGN: This population study examined baseline and 4y follow-up data from the cohort of young women participating in the Australian Longitudinal Study on Women's Health. SUBJECTS: A total of 8726 young women aged 18 - 23y at baseline. MEASURES: Height, weight and body mass index (BMI); physical activity; time spent sitting; selected eating behaviours (eg dieting, disordered eating, takeaway food consumption); cigarette smoking, alcohol consumption; parity; and socio-demographic characteristics. RESULTS: Only 44% of the women reported their BMI at follow-up to be within 5% of their baseline BMI (maintainers); 41% had gained weight and 15% had lost weight. Weight maintainers were more likely to be in managerial or professional occupations; to have never married; to be currently studying; and not to be mothers. Controlling for sociodemographic factors, weight maintainers were more likely to be in a healthy weight range at baseline, and to report that they spent less time sitting, and consumed less takeaway food, than women who gained weight. CONCLUSIONS: Fewer than half the young women in this community sample maintained their weight over this 4y period in their early twenties. Findings of widespread weight gain, particularly among those already overweight, suggest that early adulthood, which is a time of significant life changes for many women, may be an important time for implementing strategies to promote maintenance of healthy weight. Strategies which encourage decreased sitting time and less takeaway food consumption may be effective for encouraging weight maintenance at this life stage.

Stress in veterinary science students: A study at the University of Queensland

This paper reports on the results of a survey of selected University of Queensland (UQ) veterinary students aimed at elucidating factors causing stress during the five undergraduate years of the program. Students from each of the five years were asked to form six- or seven-member focus groups. Each focus group was then interviewed and their opinions sought on causes of ongoing stress and the ranking of those causes into predetermined categories. They were also asked to give their opinions on counseling services available within the university and what, if any, services they would like to see in place to help students with stress-related problems. Students in the first, third, and fourth years of the program rated academic issues as the most likely causes of ongoing stress, while students in the second and fifth years of the program ranked lifestyle and financial issues as more likely to cause ongoing stress. in most cases, students coped well with these causes of stress and tended not to use counseling services available to all UQ students. When faced with stressful issues, students looked to their classmates or family members for help and not to university counseling services. Students were also happy to approach staff members in the Veterinary School when faced with a problem. The authors nevertheless conclude that mechanisms set in place at the undergraduate level to help veterinary students cope with stress should particularly benefit those students when they become new graduates and are faced with the stresses of veterinary practice.

Mutations in the MYB intron I regulatory sequence increase transcription in colon cancers

Although MYB overexpression in colorectal cancer (CRC) is known to be a prognostic indicator for poor survival, the basis for this overexpression is unclear. Among multiple levels of MYB regulation, the most dynamic is the control of transcriptional elongation by sequences within intron I. The authors have proposed that this regulatory sequence is transcribed into an RNA stem-loop and 19-residue polyuridine tract, and is subject to mutation in CRC. When this region was examined in colorectal and breast carcinoma cell lines and tissues, the authors found frequent mutations only in CRC. It was determined that these mutations allowed increased transcription compared with the wild type sequence. These data suggest that this MYB regulatory region within intron I is subject to mutations in CRC but not breast cancer, perhaps consistent with the mutagenic insult that occurs within the colon and not mammary tissue. In CRC, these mutations may contribute to MYB overexpression, highlighting the importance of noncoding sequences in the regulation of key cancer genes. (c) 2006 Wiley-Liss, Inc.