The Dynamics of Public Goods

We analyze the replicator equation for two games closely related with the social dilemma occurring in public goods situation. In one case, players can punish defectors in their group. In another case, they can choose not to take part in the game. In both cases, interactions are not pairwise and payoffs are nonlinear. Nevertheless, the qualitative dynamics can be fully analyzed. The games offer potential solutions for the problem of the emergence of cooperation in sizeable groups of non-related individuals - a basic question in evolutionary biology and economics

How Do Payers Respond to Regulatory Actions? The Case of Bevacizumab

In February 2008, the US Food and Drug Administration (FDA) granted accelerated approval for bevacizumab for metastatic breast cancer. After public hearings in July 2010, and June 2011, the FDA revoked this approved indication in November 2011, on the basis of additional evidence regarding its risk/benefit profile. The Centers for Medicare and Medicaid Services, local Medicare contractors, and commercial payers varied in their stated intentions to cover bevacizumab after FDA's regulatory actions. We examined payer-specific trends in bevacizumab use after the FDA's regulatory actions

Global predictability of temperature extremes

Extreme temperatures are one of the leading causes of death and disease in both developed and developing countries, and heat extremes are projected to rise in many regions. To reduce risk, heatwave plans and cold weather plans have been effectively implemented around the world. However, much of the world’s population is not yet protected by such systems, including many data-scarce but also highly vulnerable regions. In this study, we assess at a global level where such systems have the potential to be effective at reducing risk from temperature extremes, characterizing (1) long-term average occurrence of heatwaves and coldwaves, (2) seasonality of these extremes, and (3) short-term predictability of these extreme events three to ten days in advance. Using both the NOAA and ECMWF weather forecast models, we develop global maps indicating a first approximation of the locations that are likely to benefit from the development of seasonal preparedness plans and/or short-term early warning systems for extreme temperature. The extratropics generally show both short-term skill as well as strong seasonality; in the tropics, most locations do also demonstrate one or both. In fact, almost 5 billion people live in regions that have seasonality and predictability of heatwaves and/or coldwaves. Climate adaptation investments in these regions can take advantage of seasonality and predictability to reduce risks to vulnerable populations

Recombinant human erythropoietin increases survival and reduces neuronal apoptosis in a murine model of cerebral malaria

<p>Abstract</p> <p>Background</p> <p>Cerebral malaria (CM) is an acute encephalopathy with increased pro-inflammatory cytokines, sequestration of parasitized erythrocytes and localized ischaemia. In children CM induces cognitive impairment in about 10% of the survivors. Erythropoietin (Epo) has – besides of its well known haematopoietic properties – significant anti-inflammatory, antioxidant and anti-apoptotic effects in various brain disorders. The neurobiological responses to exogenously injected Epo during murine CM were examined.</p> <p>Methods</p> <p>Female C57BL/6j mice (4–6 weeks), infected with <it>Plasmodium berghei </it>ANKA, were treated with recombinant human Epo (rhEpo; 50–5000 U/kg/OD, i.p.) at different time points. The effect on survival was measured. Brain pathology was investigated by TUNEL (Terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP)-digoxigenin nick end labelling), as a marker of apoptosis. Gene expression in brain tissue was measured by real time PCR.</p> <p>Results</p> <p>Treatment with rhEpo increased survival in mice with CM in a dose- and time-dependent manner and reduced apoptotic cell death of neurons as well as the expression of pro-inflammatory cytokines in the brain. This neuroprotective effect appeared to be independent of the haematopoietic effect.</p> <p>Conclusion</p> <p>These results and its excellent safety profile in humans makes rhEpo a potential candidate for adjunct treatment of CM.</p

Changes in Drug Utilization during a Gap in Insurance Coverage: An Examination of the Medicare Part D Coverage Gap

Jennifer Polinski and colleagues estimated the effect of the "coverage gap" during which US Medicare beneficiaries are fully responsible for drug costs and found that the gap was associated with a doubling in discontinuing essential medications

Linezolid for treatment of catheter-related cerebrospinal fluid infections in preterm infants

Ventriculostomy-related cerebrospinal fluid (CSF) infection remains a major problem in neonatal intensive care. The spectrum of pathogens causing these infections is dominated by coagulase-negative staphylococci, and vancomycin is the antibiotic of choice for treatment. However, vancomycin is known to have only poor penetration into the CSF when applied intravenously and is therefore being applied intraventricularly. The oxazolidinone linezolid has antibacterial activity against most drug-resistant Gram-positive bacteria and has been shown to have excellent penetration into the CSF in adults. Here, its successful use in five neonates with infected ventriculostomies is described

Data from: Topography as a driver of diversification in the Cape Floristic Region of South Africa

The rugged topography of the Cape Floristic Region (CFR), South Africa, is frequently invoked to explain the spectacular radiation of the Cape flora, but the mechanisms involved remain unclear. Where recent authors emphasize the importance of elevation gradients as stimuli for ecological speciation, earlier workers stressed the role of topography as an isolating mechanism, particularly in montane lineages. Using six Cape plant lineages, we tested whether elevation niches are phylogenetically conserved. We then assessed whether high-elevation species are more consistently range-restricted than low-elevation species, and whether high-elevation sisters show stronger range exclusivity (allopatry) and weaker ecological and phenotypic differentiation, suggestive of nonecological speciation. Elevation niches tend to be phylogenetically conserved. Also, high-elevation species are more consistently range-restricted than low-elevation species, potentially explaining the generally stronger range exclusivity of high-elevation sisters. While the high-elevation zone is less homogeneous ecologically, more data are required to demonstrate that high-elevation sister species show generally weaker ecological and phenotypic differentiation. Topographic complexity promotes geographical isolation at high elevations, thereby providing opportunities for nonecological, vicariant speciation. While recognizing the need for additional data, we suggest that the upland and lowland floras of the CFR may differ with regard to predominant speciation mode