Partition Functions for the Rigid String and Membrane at Any Temperature

Exact expressions for the partition functions of the rigid string and membrane at any temperature are obtained in terms of hypergeometric functions. By using zeta function regularization methods, the results are analytically continued and written as asymptotic sums of Riemann-Hurwitz zeta functions, which provide very good numerical approximations with just a few first terms. This allows to obtain systematic corrections to the results of Polchinski et al., corresponding to the limits $T\rightarrow 0$ and $T\rightarrow \infty$ of the rigid string, and to analyze the intermediate range of temperatures. In particular, a way to obtain the Hagedorn temperature for the rigid membrane is thus found.Comment: 20 pages, LaTeX file, UB-ECM-PF 93/

Poor nutritional status is associated with other geriatric domain impairments and adverse postoperative outcomes in onco-geriatric surgical patients – a multicentre cohort study

Background: Nutritional status (NS), though frequently affected in onco-geriatric patients, is no standard part of a geriatric assessment. The aim of this study was to analyse the association between a preoperatively impaired NS and geriatric domain impairments and adverse postoperative outcomes in onco-geriatric surgical patients. Methods: 309 patients ≥70 years undergoing surgery for solid tumours were prospectively recruited. Nine screening tools were preoperatively administered as part of a geriatric assessment. NS was based on BMI, weight loss and food intake. Odds ratio’s (OR) and 95% confidence intervals (95%CI) were estimated using logistic regression analysis. The occurrence of 30-day adverse postoperative outcomes was recorded. Results: At a median age of 76 years, 107 patients (34.6%) had an impaired NS. Decreased performance status and depression were associated with an impaired NS, when adjusted for tumour characteristics and comorbidities (ORPS>1 3.46; 95%CI 1.56-7.67. ORGDS>5 2.11; 95%CI 1.05-4.26). An impaired NS was an independent predictor for major complications (OR 3.3; 95%CI 1.6-6.8). Ten out of 11 patients who deceased had an impaired NS. Conclusion: An impaired NS is prevalent in onco-geriatric patients considered to be fit for surgery. It is associated with decreased performance status and depression. An impaired NS is a predictor for adverse postoperative outcomes. NS should be incorporated in a geriatric assessment

Phylogenomics and the rise of the angiosperms

Angiosperms are the cornerstone of most terrestrial ecosystems and human livelihoods1,2. A robust understanding of angiosperm evolution is required to explain their rise to ecological dominance. So far, the angiosperm tree of life has been determined primarily by means of analyses of the plastid genome3,4. Many studies have drawn on this foundational work, such as classification and first insights into angiosperm diversification since their Mesozoic origins5,6,7. However, the limited and biased sampling of both taxa and genomes undermines confidence in the tree and its implications. Here, we build the tree of life for almost 8,000 (about 60%) angiosperm genera using a standardized set of 353 nuclear genes8. This 15-fold increase in genus-level sampling relative to comparable nuclear studies9 provides a critical test of earlier results and brings notable change to key groups, especially in rosids, while substantiating many previously predicted relationships. Scaling this tree to time using 200 fossils, we discovered that early angiosperm evolution was characterized by high gene tree conflict and explosive diversification, giving rise to more than 80% of extant angiosperm orders. Steady diversification ensued through the remaining Mesozoic Era until rates resurged in the Cenozoic Era, concurrent with decreasing global temperatures and tightly linked with gene tree conflict. Taken together, our extensive sampling combined with advanced phylogenomic methods shows the deep history and full complexity in the evolution of a megadiverse clade

Dairy proteins and the response to pneumovax in senior citizens : a randomized, double-blind, placebo-controlled pilot study

With the progressive aging of the world's population, immunosenescence is rapidly becoming a clinical concern as it accounts for a higher incidence of severe infections and poor response to vaccines. To identify nutritional approaches that may counteract immunosenescence is of obvious importance in clinical practice. Dairy products in general and whey proteins in particular share the capacity to stimulate the immune system within the digestive tract while the antibody response to Streptococcus pneumoniae vaccine is a good marker of the immune function. We performed a controlled, randomized, double-blind pilot study to determine if an eight-week supplementation with whey protein (or soy protein used as control) could enhance the serum response to pneumococcal vaccine in healthy senior citizens. Out of 127 volunteers, 17 subjects were eligible and completed the study receiving the vaccine after four weeks of supplementation. Antibody levels were measured at baseline and the end of the study against 14 pneumococcal types and a detailed nutritional questionnaire was administered to all subjects. Subjects receiving whey protein manifested a serum response higher compared to the control soy supplementation against 12/14 bacterial types. In particular, whey led to a higher frequency of response to all four more virulent types (4, 9, 14, and 23). Calorie and protein intake data suggest a better nutritional status in the whey group. Whey protein supplementation is a promising supplement to stimulate the immune response to vaccine in senior citizens and possibly to counteract immunosenescence while larger studies are warranted

Parenting Styles and Health-Related Behavior in Childhood and Early Adolescence Results of a Longitudinal Study

Lohaus A, Vierhaus M, Ball J. Parenting Styles and Health-Related Behavior in Childhood and Early Adolescence Results of a Longitudinal Study. Journal of Early Adolescence. 2009;29(4):449-475.This study addresses the development of health-related behavior during childhood and adolescence and the protective influence of an authoritative parenting style. The study is based on two samples followed from Grades 2 through 5 and from Grades 4 through 7. The first sample consisted of 432 second graders with a mean age of 7.9 years at the beginning of the study, while the second sample consisted of 366 fourth graders with a mean age of 10.1 years. Later health behavior showed substantial correlations to previous health behavior over a 3-year interval. Moreover, there was an increase of favorable health behavior during elementary school and a decrease in the subsequent age periods. The slope for negative health behavior showed an inverted pattern. The level of this general trend was significantly affected by the perceived maternal and paternal parenting style and by gender. The significance of the results for health promotion is discussed