Paradigm of biased PAR1 (protease-activated receptor-1) activation and inhibition in endothelial cells dissected by phosphoproteomics

Thrombin is the key serine protease of the coagulation cascade and mediates cellular responses by activation of PARs (protease-activated receptors). The predominant thrombin receptor is PAR1, and in endothelial cells (ECs), thrombin dynamically regulates a plethora of phosphorylation events. However, it has remained unclear whether thrombin signaling is exclusively mediated through PAR1. Furthermore, mechanistic insight into activation and inhibition of PAR1-mediated EC signaling is lacking. In addition, signaling networks of biased PAR1 activation after differential cleavage of the PAR1 N terminus have remained an unresolved issue. Here, we used a quantitative phosphoproteomics approach to show that classical and peptide activation of PAR1 induce highly similar signaling, that low thrombin concentrations initiate only limited phosphoregulation, and that the PAR1 inhibitors vorapaxar and parmodulin-2 demonstrate distinct antagonistic properties. Subsequent analysis of the thrombin-regulated phosphosites in the presence of PAR1 inhibitors revealed that biased activation of PAR1 is not solely linked to a specific G-protein downstream of PAR1. In addition, we showed that only the canonical thrombin PAR1 tethered ligand induces extensive early phosphoregulation in ECs. Our study provides detailed insight in the signaling mechanisms downstream of PAR1. Our data demonstrate that thrombin-induced EC phosphoregulation is mediated exclusively through PAR1, that thrombin and thrombin-tethered ligand peptide induce similar phosphoregulation, and that only canonical PAR1 cleavage by thrombin generates a tethered ligand that potently induces early signaling. Furthermore, platelet PAR1 inhibitors directly affect EC signaling, indicating that it will be a challenge to design a PAR1 antagonist that will target only those pathways responsible for tissue pathology

Using Cox's Proportional Hazard Models to Implement Optimal Strategies: An Example from Behavioural Ecology

Simple behavioural rules, or "rules of thumb", which lead to behaviour that closely approximates an optimal strategy, have generated a lot of recent interest in the field of foraging behaviour. In this paper, we derive rules of thumb from a stochastic simulation model in which the foragers behave optimally. We use a particular biological system: the patch leaving behaviour of a parasitoid. We simulate parasitoids whose patch leaving behaviour is determined by a stochastic dynamic programming (SDP) model, while allowing parasitoids to make mistakes in their estimation of host density when arriving in a patch. We use Cox's proportional hazards models to obtain statistical rules of thumb from the simulated behaviour. This represents the first use of a proportional hazard approximation to generate rules of thumb from a complex optimal strategy

Возможностим развития конкуренции на рынках теплоснабжения Донбасса

Проаналізовано стан ситем теплопостачання Донбасу, виявлено зниження виробництва та відпуску теплової енергії, що викликано появою конкурента — автономного опалення. Обгрунтовано причини протиріччя законодавства, що регулює діяльність у сфері комунального теплопостачання — природної монополії, в результаті чого порушені конституційні, цивільні, споживчі права людей. Розглянуто практику регулювання ринків теплопостачання в країнах з розвиненою ринковою економікою, і можливості застосування їх досвіду в Україні. Визначено роль держави, як найважливішого регулятора, який здійснює контроль за ринком теплопостачання, і є влавником стратегічно важливих підприємств сектора. Ключові слова: централізоване теплопостачання, природна монополія, автономне опалення, конкуренція, приватний капітал, державне регулювання.Проанализировано состояние ситем теплоснабжения Донбасса, выявлено снижение производства и отпуска тепловой энергии, что вызвано появлением конкурента — автономного отопления. Обоснованы причины протеворечивости законодательства регулирующего деятельность в сфере коммунального теплоснабжения — естественной монополии, в результате чего нарушены конституционные, гражданские, потребительские права людей. Рассмотрена практика регулирования рынков теплоснабжения в странах с развитой рыночной экономикой, и возможности применения их опыта в Украине. Определена роль государства, как важнейшего регулятора, осуществляющего контроль за рынком теплоснабжения, и собственика стратегически важных предприятий сектора. Ключевые слова: централизованное теплоснабжение, естественная монополия, автономное отопление, конкуренция, частный капитал, государственное регулирование.The state of Donbass Heating System Works, showed a reduction in production and supply of heat energy that is caused by the emergence of competitors — independent heating. Substantiated reasons imperfect legislation governing activities in the field of district heating — natural monopoly, resulting in a violation of the constitutional, civil, consumer rights of people. The practical management of district heating markets in countries with developed market economies, and the possibility of applying their experience in Ukraine. Defined the place of government as an important regulator, controlling the heating market, and the owners of strategically important enterprises in the sector. Key words: district heating, natural monopoly, independent heating, competition, private capital, government regulation

Using item response theory to explore the psychometric properties of extended matching questions examination in undergraduate medical education

BACKGROUND: As assessment has been shown to direct learning, it is critical that the examinations developed to test clinical competence in medical undergraduates are valid and reliable. The use of extended matching questions (EMQ) has been advocated to overcome some of the criticisms of using multiple-choice questions to test factual and applied knowledge. METHODS: We analysed the results from the Extended Matching Questions Examination taken by 4th year undergraduate medical students in the academic year 2001 to 2002. Rasch analysis was used to examine whether the set of questions used in the examination mapped on to a unidimensional scale, the degree of difficulty of questions within and between the various medical and surgical specialties and the pattern of responses within individual questions to assess the impact of the distractor options. RESULTS: Analysis of a subset of items and of the full examination demonstrated internal construct validity and the absence of bias on the majority of questions. Three main patterns of response selection were identified. CONCLUSION: Modern psychometric methods based upon the work of Rasch provide a useful approach to the calibration and analysis of EMQ undergraduate medical assessments. The approach allows for a formal test of the unidimensionality of the questions and thus the validity of the summed score. Given the metric calibration which follows fit to the model, it also allows for the establishment of items banks to facilitate continuity and equity in exam standards

The Application of New Molecular Methods in the Investigation of a Waterborne Outbreak of Norovirus in Denmark, 2012

In December 2012, an outbreak of acute gastrointestinal illness occurred in a geographical distinct area in Denmark covering 368 households. A combined microbiological, epidemiological and environmental investigation was initiated to understand the outbreak magnitude, pathogen(s) and vehicle in order to control the outbreak. Norovirus GII.4 New Orleans 2009 variant was detected in 15 of 17 individual stool samples from 14 households. Norovirus genomic material from water samples was detected and quantified and sequencing of longer parts of the viral capsid region (>1000 nt) were applied to patient and water samples. All five purposely selected water samples tested positive for norovirus GII in levels up to 1.8×10(4) genomic units per 200 ml. Identical norovirus sequences were found in all 5 sequenced stool samples and 1 sequenced water sample, a second sequenced water sample showed 1 nt (<0.1%) difference. In a cohort study, including 256 participants, cases were defined as residents of the area experiencing diarrhoea or vomiting onset on 12-14 December 2012. We found an attack rate of 51%. Being a case was associated with drinking tap-water on 12-13 December (relative risk = 6.0, 95%CI: 1.6-22) and a dose-response relation for the mean glasses of tap-water consumed was observed. Environmental investigations suggested contamination from a sewage pipe to the drinking water due to fall in pressure during water supply system renovations. The combined microbiological, epidemiological and environmental investigations strongly indicates the outbreak was caused by norovirus contamination of the water supply system

Gaze stabilization reflexes in the mouse: New tools to study vision and sensorimotor

__abstract__ Gaze stabilization reflexes are a popular model system in neuroscience for connecting neurophysiology and behavior as well as studying the neural correlates of behavioral plasticity. These compensatory eye movements are one of the simplest motor behaviors, consisting of a more or less spherical object that rotates with three degrees of freedom, without significantly changing the load during a movement trajectory. Additionally, it is a model system where the sensory input, consisting of visual and/or vestibular stimulation, can be fully controlled. The output, reflexive compensatory eye movements and electrophysiological activity, can be recorded and correlated with the sensory input. By manipulating those reflexive eye movements by using different combinations of sensory input, motor learning can be studied in a well‐controlled environment. In this thesis, we describe several innovative approaches that can be added to the neuroscientific arsenal. We are the first lab to describe how to record three dimensional eye movements in mice using video‐oculography. Additionally, we describe how compensatory eye movements can be used to quantify contrast sensitivity; the ability to detect small increments in shades of gray on a uniform background, which is one of the main limiting factors in a wide variety of visual tasks. This new and sensitive method is useful in characterizing mouse models where vision is affected as a result of mutations, aging, retinal degeneration or neurological impairment of the visual system

The teaching of recent and violent conflicts as challenges for history education

This paper has been written with the support of Projects EDU2015-65088P from the DGICYT (Ministry of Education, Spain) and also the Project PICT2012-1594 from the ANPCYT (Argentina) coordinated by the autho