Variation in habitat choice and delayed reproduction: Adaptive queuing strategies or individual quality differences?

In most species, some individuals delay reproduction or occupy inferior breeding positions. The queue hypothesis tries to explain both patterns by proposing that individuals strategically delay breeding (queue) to acquire better breeding or social positions. In 1995, Ens, Weissing, and Drent addressed evolutionarily stable queuing strategies in situations with habitat heterogeneity. However, their model did not consider the non - mutually exclusive individual quality hypothesis, which suggests that some individuals delay breeding or occupy inferior breeding positions because they are poor competitors. Here we extend their model with individual differences in competitive abilities, which are probably plentiful in nature. We show that including even the smallest competitive asymmetries will result in individuals using queuing strategies completely different from those in models that assume equal competitors. Subsequently, we investigate how well our models can explain settleme! nt patterns in the wild, using a long-term study on oystercatchers. This long-lived shorebird exhibits strong variation in age of first reproduction and territory quality. We show that only models that include competitive asymmetries can explain why oystercatchers' settlement patterns depend on natal origin. We conclude that predictions from queuing models are very sensitive to assumptions about competitive asymmetries, while detecting such differences in the wild is often problematic.

Annual Report of the Centre for Infectious Diseases Research, Diagnostics and Screening (IDS)

Veel (ziekenhuis)laboratoria sturen het te onderzoeken materiaal van patiënten naar het Centrum Infectieziekteonderzoek, diagnostiek en screening (IDS) van het RIVM. Dit betreft vooral bijzondere diagnostiek waarvoor de laboratoria zelf geen test in huis hebben. Ook komen patiëntmaterialen binnen om te monitoren of en in welke mate bepaalde ziekteverwekkende micro-organismen voorkomen. Soms worden de ziekteverwekkers zelf ingestuurd met de vraag of IDS deze wil karakteriseren. Met de verkregen resultaten houdt het RIVM er zicht op hoe vaak en waar bepaalde micro-organismen voorkomen. Op die manier kan het RIVM snel reageren op (plotselinge) ontwikkelingen op het gebied van infectieziekten. IDS beschrijft jaarlijks de resultaten om inzenders van patiëntmaterialen inzicht te geven in wat is gedaan aan diagnostiek, screening en onderzoek naar infectieziekten. De jaarrapportage 2015 beschrijft onder andere de bijdrage van IDS aan de ebola-diagnostiek in Sierra Leone. Zeven medewerkers hielpen ter plaatse door de laboratoriumdiagnostiek uit te voeren. Verder zijn bij IDS de eerste stappen gezet om de hielprikscreening uit te breiden, en wel met de screening op Severe combined immunodeficiency (SCID). Ook wordt toegelicht hoe het komt dat het griepvaccin in 2015 onvoldoende werkte. Een deel van de onder de bevolking circulerende influenzavirussen bleek af te wijken van de virussen die in het griepvaccin waren opgenomen. Het onderzoek bij IDS bestaat er vooral uit om innovatieve laboratoriumtesten te ontwikkelen, te verbeteren en in te zetten. Dit in het belang van de openbare gezondheidszorg. Bij veel van deze onderzoeken wordt een innovatieve methode gebruikt waarmee het hele genoom van een micro-organisme in kaart kan worden gebracht (Whole Genome sequencing).Many hospital and other laboratories send their patient materials to RIVM's Centre for Infectious Diseases Research, Diagnostics and Screening (IDS) for testing, particularly if special diagnostic procedures are required for which these laboratories lack the necessary testing facilities. Patient materials are also sent to IDS in order to monitor the incidence of specific pathogenic micro-organisms. In some cases the pathogens themselves are sent to IDS for characterization. The results obtained enable RIVM to keep track of where and how frequently specific micro-organisms occur, enabling RIVM to respond rapidly to any (sudden) developments relating to infectious diseases. IDS summarizes the results of these activities in an Annual Report to provide stakeholders with insight into infectious diseases research, diagnostics and screening. The topics covered in the Annual Report for 2015 include IDS's contribution to Ebola diagnostics in Sierra Leone. Seven staff members travelled to the West African nation to provide laboratory diagnostic assistance. In addition, IDS has taken initial steps to expand its heel prick screening programme to include Severe Combined Immune Deficiency syndrome (SCID). The report also explains why the Dutch flu vaccination programme was insufficiently effective in 2015. A part of the circulating influenza viruses in the human population was found to deviate from the viruses that were included in the flu vaccine. Research at IDS is mainly focused on developing, optimizing and implementing innovative laboratory tests that can help to improve public health. Much of its research uses Whole Genome Sequencing, an innovative laboratory process that determines the complete DNA sequence of a micro-organism's genome

Having Fun in Learning Formal Specifications

There are many benefits in providing formal specifications for our software. However, teaching students to do this is not always easy as courses on formal methods are often experienced as dry by students. This paper presents a game called FormalZ that teachers can use to introduce some variation in their class. Students can have some fun in playing the game and, while doing so, also learn the basics of writing formal specifications in the form of pre- and post-conditions. Unlike existing software engineering themed education games such as Pex and Code Defenders, FormalZ takes the deep gamification approach where playing gets a more central role in order to generate more engagement. This short paper presents our work in progress: the first implementation of FormalZ along with the result of a preliminary users' evaluation. This implementation is functionally complete and tested, but the polishing of its user interface is still future work

Chikungunya virus requires an intact microtubule network for efficient viral genome delivery

Chikungunya virus (CHIKV) is a re-emerging mosquito-borne alphavirus, which has rapidly spread around the globe thereby causing millions of infections. CHIKV is an enveloped virus belonging to the Togaviridae family and enters its host cell primarily via clathrin-mediated endocytosis. Upon internalization, the endocytic vesicle containing the virus particle moves through the cell and delivers the virus to early endosomes where membrane fusion is observed. Thereafter, the nucleocapsid dissociates and the viral RNA is translated into proteins. In this study, we examined the importance of the microtubule network during the early steps of infection and dissected the intracellular trafficking behavior of CHIKV particles during cell entry. We observed two distinct CHIKV intracellular trafficking patterns prior to membrane hemifusion. Whereas half of the CHIKV virions remained static during cell entry and fused in the cell periphery, the other half showed fast-directed microtubule-dependent movement prior to delivery to Rab5-positive early endosomes and predominantly fused in the perinuclear region of the cell. Disruption of the microtubule network reduced the number of infected cells. At these conditions, membrane hemifusion activity was not affected yet fusion was restricted to the cell periphery. Furthermore, follow-up experiments revealed that disruption of the microtubule network impairs the delivery of the viral genome to the cell cytosol. We therefore hypothesize that microtubules may direct the particle to a cellular location that is beneficial for establishing infection or aids in nucleocapsid uncoating

Spectroscopic detection of brain propylene glycol in neonates: Effects of different pharmaceutical formulations of phenobarbital

Background The first choice for treatment of neonatal convulsions is intravenous phenobarbital, which contains propylene glycol (PG) as a solvent. Although PG is generally considered safe, the dosage can exceed safety thresholds in neonates. High PG levels can cause lactic acidosis. Purpose/Hypothesis To investigate a relationship between brain PG concentration and medication administered to neonates, and to study if a correlation between spectroscopically detected PG and lactate was present. Study Type Retrospective. Population Forty‐one neonates who underwent MRI/MRS. Field Strength/Sequence Short echo time single voxel MRS at 1.5T. Assessment Spectra were quantified. Concentrations of PG were correlated with medication administered, because intravenously administered phenobarbital solutions contained 10, 25, or 50 mg phenobarbital per ml, all containing 350 mg PG per ml. The interval between medication and MRI/MRS was determined. Statistical Tests Chi‐square test, Student's t‐test, Mann–Whitney U‐test and Spearman correlation. Results Eighteen neonates had brain PG >1 mM (median 3.4 mM, maximum 9.5 mM). All 18 neonates with high brain PG and 14 neonates with low brain PG (<1 mM) received phenobarbital as the only source of PG. Nine neonates did not receive any phenobarbital/PG‐containing medication. Neonates with high brain PG more often received 10 mg/ml phenobarbital, resulting in higher PG dose (high vs. low brain PG (median [interquartile range]: 1400 [595] vs. 350 [595] mg/kg, respectively, P < 0.01). In addition, the interval between the last phenobarbital dose and MRI was shorter in the high brain PG group (high vs. low brain PG: 16 [21] vs. 95 [83] hours, respectively, P < 0.001). Within neonates that received phenobarbital, there was no conclusive correlation between spectroscopically detected PG and lactate (Spearman's rho = 0.23, P = 0.10). Data Conclusion These MRS findings may increase awareness of potentially toxic PG concentrations in the neonatal brain due to intravenous phenobarbital administration and its dependence on the phenobarbital formulation used. Level of Evidence:4Technical Efficacy:Stage