Phenological dynamics of four populations of Handroanthus spongiosus in seasonally dry tropical forest in Brazil.

The scarcity of phenological studies based on different populations of tropical forest trees limits seed management and collection for reforestation efforts. Precipitation is the primary factor driving tropical plant phenology in seasonal environments, although other environmental variables and plant traits may be associated. We examined the seasonality, synchrony, and intensities of the vegetative and reproductive phenophases of four populations of Handroanthus spongiosus, an endangered species, under similar climate regimes in a seasonally dry tropical forest, in northeastern Brazil. We expected to observe some divergence in the phenologies of the populations related to distinct functional traits selected for by differences in rainfall and soil properties. Mature trees (n = 87) were monitored during a three-year period. Seasonality was examined using circular statistics, and the influences of environmental variables on phenophases were investigated using generalized additive models. Variations in intensities and activity indices were identified among the different populations. Vegetative phenophases were seasonal, driven by precipitation and photoperiod, with leaf longevity of up to 7 months; budding peaked in February-March, while leaf fall peaked in April and October. The reproductive phenophases were found to be seasonal, during the rainy season (November to April), influenced by temperature and photoperiod. The slight divergences noted among the phenological behaviors of the populations were related to distinct functional traits (e.g., tree height, stem diameter) selected for by differences in certain environmental variables (rainfall volumes and soil properties). Given ongoing global climate changes, increases in leaf fall and reductions of flowering intensity, as verified here, will likely be observed

How well do adolescents recall use of mobile telephones? Results of a validation study

<p>Abstract</p> <p>Background</p> <p>In the last decade mobile telephone use has become more widespread among children. Concerns expressed about possible health risks have led to epidemiological studies investigating adverse health outcomes associated with mobile telephone use. Most epidemiological studies have relied on self reported questionnaire responses to determine individual exposure. We sought to validate the accuracy of self reported adolescent mobile telephone use.</p> <p>Methods</p> <p>Participants were recruited from year 7 secondary school students in Melbourne, Australia. Adolescent recall of mobile telephone use was assessed using a self administered questionnaire which asked about number and average duration of calls per week. Validation of self reports was undertaken using Software Modified Phones (SMPs) which logged exposure details such as number and duration of calls.</p> <p>Results</p> <p>A total of 59 adolescents participated (39% boys, 61% girls). Overall a modest but significant rank correlation was found between self and validated number of voice calls (ρ = 0.3, P = 0.04) with a sensitivity of 57% and specificity of 66%. Agreement between SMP measured and self reported duration of calls was poorer (ρ = 0.1, P = 0.37). Participants whose parents belonged to the 4^thsocioeconomic stratum recalled mobile phone use better than others (ρ = 0.6, P = 0.01).</p> <p>Conclusion</p> <p>Adolescent recall of mobile telephone use was only modestly accurate. Caution is warranted in interpreting results of epidemiological studies investigating health effects of mobile phone use in this age group.</p

Influences on pre-hospital delay in the diagnosis of colorectal cancer: a systematic review

Colorectal cancer is a major global health problem, with survival varying according to stage at diagnosis. Delayed diagnosis can result from patient, practitioner or hospital delay. This paper reports the results of a review of the factors influencing pre-hospital delay – the time between a patient first noticing a cancer symptom and presenting to primary care or between first presentation and referral to secondary care. A systematic methodology was applied, including extensive searches of the literature published from 1970 to 2003, systematic data extraction, quality assessment and narrative data synthesis. Fifty-four studies were included. Patients' non-recognition of symptom seriousness increased delay, as did symptom denial. Patient delay was greater for rectal than colon cancers and the presence of more serious symptoms, such as pain, reduced delay. There appears to be no relationship between delay and patients' age, sex or socioeconomic status. Initial misdiagnosis, inadequate examination and inaccurate investigations increased practitioner delay. Use of referral guidelines may reduce delay, although evidence is currently limited. No intervention studies were identified. If delayed diagnosis is to be reduced, there must be increased recognition of the significance of symptoms among patients, and development and evaluation of interventions that are designed to ensure appropriate diagnosis and examination by practitioners

Outline of a Theory of Scientific Aesthetics

I offer a theory of art that is based on science. I maintain that, as any other human activity, art can be studied with the tools of science. This does not mean that art is scientific, but aesthetics, the theory of art, can be formulated in accord with our scientific knowledge. I present elucidations of the concepts of aesthetic experience, art, work of art, artistic movement, and I discuss the ontological status of artworks from the point of view of scientific philosophy.Fil: Romero, Gustavo Esteban. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; Argentin

Social Relationships and Mortality Risk: A Meta-analytic Review

In a meta-analysis, Julianne Holt-Lunstad and colleagues find that individuals' social relationships have as much influence on mortality risk as other well-established risk factors for mortality, such as smoking