Effects of brood manipulation costs on optimal sex allocation in social hymenoptera.

In eusocial Hymenoptera, queens and workers are in conflict over optimal sex allocation. Sex ratio theory, while generating predictions on the extent of this conflict under a wide range of conditions, has largely neglected the fact that worker control of investment almost certainly requires the manipulation of brood sex ratio. This manipulation is likely to incur costs, for example, if workers eliminate male larvae or rear more females as sexuals rather than workers. In this article, we present a model of sex ratio evolution under worker control that incorporates costs of brood manipulation. We assume cost to be a continuous, increasing function of the magnitude of sex ratio manipulation. We demonstrate that costs counterselect sex ratio biasing, which leads to less female-biased population sex ratios than expected on the basis of relatedness asymmetry. Furthermore, differently shaped cost functions lead to different equilibria of manipulation at the colony level. While linear and accelerating cost functions generate monomorphic equilibria, decelerating costs lead to a process of evolutionary branching and hence split sex ratios.

Appropriate end-points for right results in the age of antiangiogenic agents: Future options for phase II trials in patients with recurrent glioblastoma.

The progression-free survival rate at 6months (PFS-6) has long been considered the best end-point for assessing the efficacy of new agents in phase II trials in patients with recurrent glioblastoma. However, due to the introduction of antiangiogenic agents in this setting, and their intrinsic propensity to alter neuroradiological disease assessment by producing pseudoregression, any end-point based on neuroradiological modifications should be reconsidered. Further, statistically significant effects on progression-free survival (PFS) only should not automatically be considered reliable evidence of meaningful clinical benefit. In this context, because of its direct and unquestionable clinical relevance, overall survival (OS) represents the gold standard end-point for measuring clinical efficacy, despite the disadvantage that it is influenced by subsequent therapies and usually takes longer time to be evaluated. Therefore, while awaiting novel imaging criteria for response evaluation and/or new imaging tools to distinguish between 'true' and 'pseudo'-responses to antiangiogenic agents, the measurement of OS or OS rates should be considered primary end-points, also in phase II trials with these agents.

Topics in public finance: social security and taxation

Summary The field of public finance focuses on the spending and taxing activities of governments and their influence on the allocation of resources and distribution of income. This work covers in three parts different topics related to public finance which are currently widely discussed in media and politics. The first two parts deal with issues on social security, which is in general one of the biggest spending shares of governments. The third part looks at the main income source of governments by analyzing the perceived value of tax competition. Part one deals with the current problem of increased early retirement by focusing on Switzerland as a special case. Early retirement is predominantly considered to be the result of incentives set by social security and the tax system. But the Swiss example demonstrates that the incidence of early retirement has dramatically increased even in the absence of institutional changes. We argue that the wealth effect also plays an important role in the retirement decision for middle and high income earners. An actuarially fair, but mandatory funded system with a relatively high replacement rate may thus contribute to a low labor market participation rate of elderly workers. We provide evidence using a unique dataset on individual retirement decisions in Swiss pension funds, allowing us to perfectly control for pension scheme details. Our findings suggest that affordability is a key determinant in the retirement decisions. The higher the accumulated pension capital, the earlier men, and to a smaller extent women, tend to leave the workforce. The fact that early retirement has become much more prevalent in the last 15 years is a further indicator of the importance of a wealth effect, as the maturing of the Swiss mandatory funded pension system over that period has led to an increase in the effective replacement rates for middle and high income earners. Part two covers the theoretical side of social security. Theories analyzing optimal social security benefits provide important qualitative results, by mainly using one general type of an economy. Economies are however very diverse concerning numerous aspects, one of the most important being the wealth level. This can lead to significant quantitative benefit differences that imply differences in replacement rates and levels of labor supply. We focus on several aspects related to this fact. In a within cohort social security model, we introduce disability insurance with an imperfect screening mechanism. We then vary the wealth level of the model economy and analyze how the optimal social security benefit structure or equivalently, the optimal replacement rates, changes depending on the wealth level of the economy, and if the introduction of disability insurance into a social security system is preferable for all economies. Second, the screening mechanism of disability insurance and the threshold level at which people are defined as disabled can differ. For economies with different wealth levels, we determine for different thresholds the screening level that maximizes social welfare. Finally, part three turns to the income of governments, by adding an element to the controversy on tax competition versus tax harmonization.2 Inter-jurisdictional tax competition can generate at least two potential benefits or costs: On a public level, tax competition may result in a lower or higher efficiency in the production of public services. But there is also a more private benefit in the form of an option for individuals to move to a community with a lower tax rate in the future. To explore the value citizens attach to tax competition we analyze a unique popular vote for a complete tax harmonization between communities in the third largest Swiss canton, Vaud. Although a majority of voters would have seemingly benefited from replacing the current tax rate by a revenue-neutral average tax rate, the proposal was rejected by a large margin. Our estimates suggest that the estimated combined perceived benefit from tax competition is in the range of 10%.

Genetic variability in a population of arbuscular mycorrhizal fungi causes variation in plant growth.

Different species of arbuscular mycorrhizal fungi (AMF) alter plant growth and affect plant coexistence and diversity. Effects of within-AMF species or within-population variation on plant growth have received less attention. High genetic variation exists within AMF populations. However, it is unknown whether genetic variation contributes to differences in plant growth. In our study, a population of AMF was cultivated under identical conditions for several generations prior to the experiments thus avoiding environmental maternal effects. We show that genetically different Glomus intraradices isolates from one AMF population significantly alter plant growth in an axenic system and in greenhouse experiments. Isolates increased or reduced plant growth meaning that plants potentially receive benefits or are subject to costs by forming associations with different individuals in the AMF population. This shows that genetic variability in AMF populations could affect host-plant fitness and should be considered in future research to understand these important soil organisms.

Detection of erythropoiesis-stimulating agents in human anti-doping control: past, present and future.

Stimulation of erythropoiesis is one of the most efficient ways of doping. This type of doping is advantageous for aerobic physical exercise and of particular interest to endurance athletes. Erythropoiesis, which takes place in bone marrow, is under the control of EPO, a hormone secreted primarily by the kidneys when the arterial oxygen tension decreases. In certain pathological disorders, such as chronic renal failure, the production of EPO is insufficient and results in anemia. The pharmaceutical industry has, thus, been very interested in developing drugs that stimulate erythropoiesis. With this aim, various strategies have been, and continue to be, envisaged, giving rise to an expanding range of drugs that are good candidates for doping. Anti-doping control has had to deal with this situation by developing appropriate methods for their detection. This article presents an overview of both the drugs and the corresponding methods of detection, and thus follows a roughly chronological order.

Differential effect of Charlson index and its components on in-hospital mortality and health costs

Introduction: The Charlson index (Charlson, 1987) is a commonly used comorbidity index in outcome studies. Still, the use of different weights makes its calculation cumbersome, while the sum of its components (comorbidities) is easier to compute. In this study, we assessed the effects of 1) the Charlson index adapted for the Swiss population and 2) the sum of its components (number of comorbidities, maximum 15) on a) in-hospital deaths and b) cost of hospitalization. Methods: Anonymous data was obtained from the administrative database of the department of internal medicine of the Lausanne University Hospital (CHUV). All hospitalizations of adult (>=18 years) patients occurring between 2003 and 2011 were included. For each hospitalization, the Charlson index and the number of comorbidities were calculated. Analyses were conducted using Stata. Results: Data from 32,741 hospitalizations occurring between 2003 and 2011 was analyzed. On bivariate analysis, both the Charlson index and the number of comorbidities were significantly and positively associated with in hospital death. Conversely, multivariate adjustment for age, gender and calendar year using Cox regression showed that the association was no longer significant for the number of comorbidities (table). On bivariate analysis, hospitalization costs increased both with Charlson index and with number of comorbidities, but the increase was much steeper for the number of comorbidities (figure). Robust regression after adjusting for age, gender, calendar year and duration of hospital stay showed that the increase in one comorbidity led to an average increase in hospital costs of 321 CHF (95% CI: 272 to 370), while the increase in one score point of the Charlson index led to a decrease in hospital costs of 49 CHF (95% CI: 31 to 67). Conclusion: Charlson index is better than the number of comorbidities in predicting in-hospital death. Conversely, the number of comorbidities significantly increases hospital costs.

Pancreatic stone protein: a marker of organ failure and outcome in ventilator-associated pneumonia.

Background: Ventilator-associated pneumonia (VAP) is the most common hospital-acquired, life-threatening infection. Poor outcome and health-care costs of nosocomial pneumonia remain a global burden. Currently, physicians rely on their experience to discriminate patients with good and poor outcome. However, standardized prognostic measures might guide medical decisions in the future. Pancreatic stone protein (PSP)/regenerating protein (reg) is associated with inflammation, infection, and other disease-related stimuli. The prognostic value of PSP/reg among critically ill patients is unknown. The aim of this pilot study was to evaluate PSP/reg in VAP.Methods: One hundred one patients with clinically diagnosed VAP were assessed. PSP/reg was retrospectively analyzed using deep-frozen serum samples from VAP onset up to day 7. The main end point was death within 28 days after VAP onset.Results: Serum PSP/reg was associated with the sequential organ failure assessment score from VAP onset (Spearman rank correlation coefficient 0.49 P < .001) up to day 7. PSP/reg levels at VAP onset were elevated in nonsurvivors (n = 20) as compared with survivors (117.0 ng/mL [36.1-295.3] vs 36.3 ng/mL [21.0-124.0] P = .011). The areas under the receiver operating characteristic curves of PSP/reg to predict mortality/survival were 0.69 at VAP onset and 0.76 at day 7. Two PSP/reg cutoffs potentially allow for identification of individuals with a particularly good and poor outcome. Whereas PSP/reg levels below 24 ng/mL at YAP onset were associated with a good chance of survival, levels above 177 ng/mL at day 7 were present in patients with a very poor outcome.Conclusions: Serum PSP/reg is a biomarker related to organ failure and outcome in patients with VAP.