Branching annihilating random walks with parity conservation on a square lattice

Using Monte Carlo simulations we have studied the transition from an "active" steady state to an absorbing "inactive" state for two versions of the branching annihilating random walks with parity conservation on a square lattice. In the first model the randomly walking particles annihilate when they meet and the branching process creates two additional particles; in the second case we distinguish particles and antiparticles created and annihilated in pairs. Quite distinct critical behavior is found in the two cases, raising the question of what determines universality in this kind of systems.Comment: 4 pages, 4 EPS figures include

Directed percolation with an absorbing boundary

We consider directed percolation with an absorbing boundary in 1+1 and 2+1 dimensions. The distribution of cluster lifetimes and sizes depend on the boundary. The new scaling exponents can be related to the exponents characterizing standard directed percolation in 1+1 dimension. In addition, we investigate the backbone cluster and red bonds, and calculate the distribution of living sites along the absorbing boundary.Comment: 10 latex pages, including 4 figure

The Calgary student run clinic in context: a mixed-methods case study

Background: Student Run Clinics (SRCs) provide students with clinical education while caring for underserved populations. While much of the research on SRCs comes from the USA, SRCs in other contexts need to be appraised in the context of the systems they interact with. This study explored how stakeholders in the University of Calgary’s SRC perceived its purpose and beneficiaries with respect to patients, students, undergraduate medical education, and its intersections within the healthcare system in Calgary.  Methods: Data came from the SRC’s EMR and stakeholder interviews at the Inn from the Cold (IFTC) shelter. Qualitative data were analyzed using standard grounded theory techniques. Results: There were 13 interviews - seven with student clinicians and six with preceptors and other stakeholders. Interviews highlighted the uncertainty of the SRCs role. Majority of participants saw the SRC as facilitating further access to other healthcare services, while some commented on its primarily education-focused role. Major limitations in the SRC’s scope of care and its integration with other services were identified. Conclusion: SRCs need to consider theiraccountabilities, both educational and healthcare-focused at individual and organization levels, in order to function as responsible healthcare providers in Calgary

The impact of schizophrenia and intelligence on the relationship between age and brain volume

Age has been shown to have an impact on both grey (GM) and white matter (WM) volume, with a steeper slope of age-related decline in schizophrenia compared to healthy controls. In schizophrenia, the relation between age and brain volume is further complicated by factors such as lower intelligence, antipsychotic medication, and cannabis use, all of which have been shown to have independent effects on brain volume. In a study of first-episode, antipsychotic-naïve schizophrenia patients (N = 54) and healthy controls (N = 56), we examined the effects of age on whole brain measures of GM and WM volume, and whether these relationships were moderated by schizophrenia and intelligence (IQ). Secondarily, we examined lifetime cannabis use as a moderator of the relationship between age and brain volume. Schizophrenia patients had lower GM volumes than healthy controls but did not differ on WM volume. We found an age effect on GM indicating that increasing age was associated with lower GM volumes, which did not differ between groups. IQ did not have a direct effect on GM, but showed a trend-level interaction with age, suggesting a greater impact of age with lower IQ. There were no age effects on WM volume, but a direct effect of IQ, with higher IQ showing an association with larger WM volume. Lifetime cannabis use did not alter these findings significantly. This study points to effects of schizophrenia on GM early in the illness, before antipsychotic treatment is initiated, suggesting that WM changes may occur later in the disease process

Dipolar interaction between two-dimensional magnetic particles

We determine the effective dipolar interaction between single domain two-dimensional ferromagnetic particles (islands or dots), taking into account their finite size. The first correction term decays as 1/D^5, where D is the distance between particles. If the particles are arranged in a regular two-dimensional array and are magnetized in plane, we show that the correction term reinforces the antiferromagnetic character of the ground state in a square lattice, and the ferromagnetic one in a triangular lattice. We also determine the dipolar spin-wave spectrum and evaluate how the Curie temperature of an ensemble of magnetic particles scales with the parameters defining the particle array: height and size of each particle, and interparticle distance. Our results show that dipolar coupling between particles might induce ferromagnetic long range order at experimentally relevant temperatures. However, depending on the size of the particles, such a collective phenomenon may be disguised by superparamagnetism.Comment: 11 pages, 5 figure

Spøgelsescyklisme – Udbredelse, kendetegn og risiko: Artikel

En spøgelsescyklist er en cyklist, som ulovligt cykler mod færdselsretningen, dvs. i den forkerte side af vejen på veje med to eller flere kørespor. I dette projekt er spøgelsescyklister inddelt i grønne, gule og røde spøgelsescyklister, som er cyklister, som cykler hhv. kort (under 50 m), mellemlangt (50-500 m) og langt (over 500 m) mod færdselsretningen. Betegnelsen spøgelsescyklist er inspireret af spøgelsesbilist, som er en bilist, der kører mod færdselsretningen. Spøgelsesbilisme har fået stor opmærksomhed i mange år, mens opmærksomheden mod spøgelsescyklisme har været begrænset. I denne artikel har vi derfor rettet opmærksomheden mod netop spøgelsescyklisme.Formålet med projektet har været at udforske spøgelsescyklistfænomen nærmere, og konkret at undersøge 1) hvor mange de er, 2) hvornår de findes, 3) hvor de findes, 4) hvem de er, 5) hvorfor de findes, 6) hvor farlige de er og 7) hvordan antallet kan reduceres. For at undersøge disse delmål har vi foretaget 1) litteraturstudie af danske og udenlandske studier, erfaringer og tiltag, 2) analyse af 21 stræknings- og krydstællinger af cykeltrafik i København og Aarhus, 3) registrering af kendetegn og adfærd for 750 spøgelsescyklister i Aarhus, 4) videooptagelse og -analyse på fem lokaliteter i Aarhus, 5) stopinterview i trafikken af 50 spøgelsescyklister i Aarhus, og 6) landsdækkende web-spørgeundersøgelse blandt 1010 repræsentativt udvalgte danske trafikanter

The prognostic effect of cardiac rehabilitation in the era of acute revascularisation and statin therapy : A systematic review and meta-analysis of randomized and non-randomized studies - The Cardiac Rehabilitation Outcome Study (CROS)

BACKGROUND: The prognostic effect of multi-component cardiac rehabilitation (CR) in the modern era of statins and acute revascularisation remains controversial. Focusing on actual clinical practice, the aim was to evaluate the effect of CR on total mortality and other clinical endpoints after an acute coronary event. DESIGN: Structured review and meta-analysis. METHODS: Randomised controlled trials (RCTs), retrospective controlled cohort studies (rCCSs) and prospective controlled cohort studies (pCCSs) evaluating patients after acute coronary syndrome (ACS), coronary artery bypass grafting (CABG) or mixed populations with coronary artery disease (CAD) were included, provided the index event was in 1995 or later. RESULTS: Out of n = 18,534 abstracts, 25 studies were identified for final evaluation (RCT: n = 1; pCCS: n = 7; rCCS: n = 17), including n = 219,702 patients (after ACS: n = 46,338; after CABG: n = 14,583; mixed populations: n = 158,781; mean follow-up: 40 months). Heterogeneity in design, biometrical assessment of results and potential confounders was evident. CCSs evaluating ACS patients showed a significantly reduced mortality for CR participants (pCCS: hazard ratio (HR) 0.37, 95% confidence interval (CI) 0.20-0.69; rCCS: HR 0.64, 95% CI 0.49-0.84; odds ratio 0.20, 95% CI 0.08-0.48), but the single RCT fulfilling Cardiac Rehabilitation Outcome Study (CROS) inclusion criteria showed neutral results. CR participation was also associated with reduced mortality after CABG (rCCS: HR 0.62, 95% CI 0.54-0.70) and in mixed CAD populations. CONCLUSIONS: CR participation after ACS and CABG is associated with reduced mortality even in the modern era of CAD treatment. However, the heterogeneity of study designs and CR programmes highlights the need for defining internationally accepted standards in CR delivery and scientific evaluation

Participant- and disease-related factors as independent predictors of treatment outcomes in the RESTORE-IMI 2 clinical trial: A multivariable regression analysis

BACKGROUND: In the RESTORE-IMI 2 trial, imipenem/cilastatin/relebactam (IMI/REL) was noninferior to piperacillin/tazobactam in treating hospital-acquired bacterial pneumonia/ventilator-associated bacterial pneumonia. This post hoc analysis was conducted to determine independent predictors of efficacy outcomes in the RESTORE-IMI 2 trial, to assist in treatment decision making. METHODS: A stepwise multivariable regression analysis was conducted to identify variables that were independently associated with day 28 all-cause mortality (ACM), favorable clinical response at early follow-up (EFU), and favorable microbiologic response at end of treatment (EOT). The analysis accounted for the number of baseline infecting pathogens and in vitro susceptibility to randomized treatment. RESULTS: Vasopressor use, renal impairment, bacteremia at baseline, and Acute Physiologic Assessment and Chronic Health Evaluation (APACHE) II scores ≥15 were associated with a greater risk of day 28 ACM. A favorable clinical response at EFU was associated with normal renal function, an APACHE II score \u3c15, no vasopressor use, and no bacteremia at baseline. At EOT, a favorable microbiologic response was associated with IMI/REL treatment, normal renal function, no vasopressor use, nonventilated pneumonia at baseline, intensive care unit admission at randomization, monomicrobial infections at baseline, and absence of CONCLUSIONS: This analysis, which accounted for baseline pathogen susceptibility, validated well-recognized patient- and disease-related factors as independent predictors of clinical outcomes. These results lend further support to the noninferiority of IMI/REL to piperacillin/tazobactam and suggests that pathogen eradication may be more likely with IMI/REL. CLINICAL TRIALS REGISTRATION: NCT02493764

A new treatment for eating disorders combining physical exercise and dietary therapy (the PED-t): experiences from patients who dropped out

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Lynx1 and Aβ1–42 bind competitively to multiple nicotinic acetylcholine receptor subtypes

AbstractLynx1 regulates synaptic plasticity in the brain by regulating nicotinic acetylcholine receptors (nAChRs). It is not known to which extent Lynx1 can bind to endogenous nAChR subunits in the brain or how this interaction is affected by Alzheimer's disease pathology. We apply affinity purification to demonstrate that a water-soluble variant of human Lynx1 (Ws-Lynx1) isolates α3, α4, α5, α6, α7, β2, and β4 nAChR subunits from human and rat cortical extracts, and rat midbrain and olfactory bulb extracts, suggesting that Lynx1 forms complexes with multiple nAChR subtypes in the human and rodent brain. Incubation with Ws-Lynx1 decreases nicotine-mediated extracellular signal–regulated kinase phosphorylation in PC12 cells and striatal neurons, indicating that binding of Ws-Lynx1 is sufficient to inhibit signaling downstream of nAChRs. The effect of nicotine in PC12 cells is independent of α7 or α4β2 nAChRs, suggesting that Lynx1 can affect the function of native non-α7, non-α4β2 nAChR subtypes. We further show that Lynx1 and oligomeric β-amyloid1–42 compete for binding to several nAChR subunits, that Ws-Lynx1 prevents β-amyloid1–42–induced cytotoxicity in cortical neurons, and that cortical Lynx1 levels are decreased in a transgenic mouse model with concomitant β-amyloid and tau pathology. Our data suggest that Lynx1 binds to multiple nAChR subtypes in the brain and that this interaction might have functional and pathophysiological implications in relation to Alzheimer's disease