Sexual dimorphism in resource acquisition and deployment: both size and timing matter.

Background and Aims The males and females of many dioecious plant species differ from one another in important life-history traits, such as their size. If male and female reproductive functions draw on different resources, for example, one should expect males and females to display different allocation strategies as they grow. Importantly, these strategies may differ not only between the two sexes, but also between plants of different age and therefore size. Results are presented from an experiment that asks whether males and females of Mercurialis annua, an annual plant with indeterminate growth, differ over time in their allocation of two potentially limiting resources (carbon and nitrogen) to vegetative (below-and above-ground) and reproductive tissues.Methods Comparisons were made of the temporal patterns of biomass allocation to shoots, roots and reproduction and the nitrogen content in the leaves between the sexes of M. annua by harvesting plants of each sex after growth over different periods of time.Key Results and Conclusions Males and females differed in their temporal patterns of allocation. Males allocated more to reproduction than females at early stages, but this trend was reversed at later stages. Importantly, males allocated proportionally more of their biomass towards roots at later stages, but the roots of females were larger in absolute terms. The study points to the important role played by both the timing of resource deployment and the relative versus absolute sizes of the sinks and sources in sexual dimorphism of an annual plant.

Men perform comparably to women in a perspective taking task after administration of intranasal oxytocin but not after placebo

Oxytocin (OT) is thought to play an important role in human interpersonal information processing and behavior. By inference, OT should facilitate empathic responding, i.e. the ability to feel for others and to take their perspective. In two independent double-blind, placebo-controlled between-subjects studies, we assessed the effect of intranasally administered OT on affective empathy and perspective taking, whilst also examining potential sex differences (e.g., women being more empathic than men). In study 1, we provided 96 participants (48 men) with an empathy scenario and recorded self reports of empathic reactions to the scenario, while in study 2, a sample of 120 individuals (60 men) performed a computerized implicit perspective taking task. Whilst results from Study 1 showed no influence of OT on affective empathy, we found in Study 2 that OT exerted an effect on perspective taking ability in men. More specifically, men responded faster than women in the placebo group but they responded as slowly as women in the OT group. We conjecture that men in the OT group adopted a social perspective taking strategy, such as did women in both groups, but not men in the placebo group. On the basis of results across both studies, we suggest that self-report measures (such as used in Study 1) might be less sensitive to OT effects than more implicit measures of empathy such as that used in Study 2. If these assumptions are confirmed, one could infer that OT effects on empathic responses are more pronounced in men than women, and that any such effect is best studied using more implicit measures of empathy rather than explicit self-report measures.

Endocrine response and perceived stress test during an experimental challenge task in adult survivors of a childhood cancer.

BACKGROUND: Although long-term implications of cancer in childhood or adolescence with regard to medical conditions are well documented, the impact on mental health and on response to stress, which may be an indicator of psychological vulnerability, is not yet well understood. In this study, psychological and physiological responses to stress were examined.¦PROCEDURE: Fifty-three participants aged 18-39 years (n = 25 survivors of childhood or adolescence cancer, n = 28 controls) underwent an experimental stress test, the Trier Social Stress Test (TSST). Participants were asked to provide repeated evaluations of perceived stress on visual-analogical scales and blood samples were collected before and after the TSST to measure plasma cortisol.¦RESULTS: The psychological perception of stress was not different between the two groups. However, the cancer survivors group showed a higher global plasma cortisol level as well as higher amplitude in the response to the TSST. The global cortisol level in cancer survivors was increased when depression symptoms were present. The subjective perception of stress and the plasma cortisol levels were only marginally correlated in both groups.¦CONCLUSIONS: It is suggested that the exposure to a life-threatening experience in childhood/adolescence increases the endocrine response to stress, and that the presence of depressive symptoms is associated with an elevation of plasma cortisol levels. A better knowledge of these mechanisms is important given that the dysregulations of the stress responses may cause psychological vulnerability. Pediatr Blood Cancer 2012; 59: 138-143. © 2011 Wiley Periodicals, Inc.

Advance directives and the impact of timing. A qualitative study with Swiss general practitioners.

PRINCIPLES: Advance directives are seen as an important tool for documenting the wishes of patients who are no longer competent to make decisions in regards to their medical care. Due to their nature, approaching the subject of advance directives with a patient can be difficult for both the medical care provider and the patient. This paper focuses on general practitioners' perspectives regarding the timing at which this discussion should take place, as well as the advantages and disadvantages of the different moments. METHODS: In 2013, 23 semi-structured face-to-face interviews were performed with Swiss general practitioners. Interviews were analysed using qualitative content analysis. RESULTS: In our sample, 23 general practitioners provided different options that they felt were appropriate moments: either (a) when the patient is still healthy, (b) when illness becomes predominant, or (c) when a patient has been transferred to a long-term care facility. Furthermore, general practitioners reported uncertainty and discomfort regarding initiating the discussion. CONCLUSION: The distinct approaches, perspectives and rationales show that there is no well-defined or "right" moment. However, participants often associated advance directives with death. This link caused discomfort and uncertainty, which led to hesitation and delay on the part of general practitioners. Therefore we recommend further training on how to professionally initiate a conversation about advance directives. Furthermore, based on our results and experience, we recommend an early approach with healthy patients paired with later regular updates as it seems to be the most effective way to inform patients about their end-of-life care options.

The alcohol purchase task in young men from the general population.

BACKGROUND: The alcohol purchase task (APT), which presents a scenario and asks participants how many drinks they would purchase and consume at different prices, has been used among students and small clinical samples to obtain measures of alcohol demand but not in large, general population samples. METHODS: We administered the APT to a large sample of young men from the general population (Cohort Study on Substance Use Risk Factors). Participants who reported drinking in the past year (n=4790), reported on past 12 months alcohol use, on DSM-5 alcohol use disorder (AUD) criteria and on alcohol related consequences were included. RESULTS: Among the APT's demand parameters, intensity was 8.7 (SD=6.5) indicating that, when drinks are free, participants report a planned consumption of almost 9 drinks. The maximum alcohol expenditure (Omax) was over 35CHF (1CHF=1.1USD) and the demand became elastic (Pmax) at 8.4CHF (SD=5.6). The mean price at which the consumption was suppressed was 15.6CHF (SD=5.4). Exponential equation provided a satisfactory fit to individual responses (mean R(2): 0.8, median: 0.8). Demand intensity was correlated with alcohol use, number of AUD criteria and number of consequences (all r≥0.3, p<0.0001). Omax was correlated with alcohol use (p<0.0001). The elasticity parameter was weakly correlated with alcohol use in the expected direction. CONCLUSION: The APT measures are useful in characterizing demand for alcohol in young men in the general population. Demand may provide a clinically useful index of strength of motivation for alcohol use in general population samples.

How critical is timing for the diagnosis of influenza in general practice?

QUESTIONS UNDER STUDY: The diagnostic significance of clinical symptoms/signs of influenza has mainly been assessed in the context of controlled studies with stringent inclusion criteria. There was a need to extend the evaluation of these predictors not only in the context of general practice but also according to the duration of symptoms and to the dynamics of the epidemic. PRINCIPLES: A prospective study conducted in the Medical Outpatient Clinic in the winter season 1999-2000. Patients with influenza-like syndrome were included, as long as the primary care physician envisaged the diagnosis of influenza. The physician administered a questionnaire, a throat swab was performed and a culture acquired to document the diagnosis of influenza. RESULTS: 201 patients were included in the study. 52% were culture positive for influenza. By univariate analysis, temperature >37.8 degrees C (OR 4.2; 95% CI 2.3-7.7), duration of symptoms <48 hours (OR 3.2; 1.8-5.7), cough (OR 3.2; 1-10.4) and myalgia (OR 2.8; 1.0-7.5) were associated with a diagnosis of influenza. In a multivariable logistic analysis, the best model predicting influenza was the association of a duration of symptom <48 hours, medical attendance at the beginning of the epidemic (weeks 49-50), fever >37.8 and cough, with a sensitivity of 79%, specificity of 69%, positive predictive value of 67%, negative predictive value of 73% and an area under the ROC curve of 0.74. CONCLUSIONS: Besides relevant symptoms and signs, the physician should also consider the duration of symptoms and the epidemiological context (start, peak or end of the epidemic) in his appraisal, since both parameters considerably modify the value of the clinical predictors when assessing the probability of a patient having influenza.