Grand Canonical Evolution for the Kac Model

We study a model of random colliding particles interacting with an infinite reservoir at fixed temperature and chemical potential. Interaction between the particles is modeled via a Kac master equation \cite{kac}. Moreover, particles can leave the system toward the reservoir or enter the system from the reservoir. The system admits a unique steady state given by the Grand Canonical Ensemble at temperature $T=\beta^{-1}$ and chemical potential $\chi$. We show that any initial state converges exponentially to equilibrium by computing the spectral gap of the generator in a suitable $L^2$ space and by showing exponential decrease of the relative entropy with respect to the steady state. We also show propagation of chaos and thus the validity of a Boltzmann-Kac type equation for the particle density in the infinite system limit

The Relationship of Emotions and Burnout to Medical Student's Academic Performance

Phenomenon: Medical school curricula challenge even the most adept learner, potentially leading to feelings of burnout. When faced with uncertainties in a new curriculum, confidence in achieving academic goals may be threatened. We previously found associations between academic performance and pride, hope, anxiety, and shame in medical students. Are these emotions still associated in the context of an evolving curriculum? Approach: All 1st- and 2nd-year medical students were invited to participate in a survey study (n = 264). Year 1 students were in the first semester of the new curriculum. The Hope, Pride, Shame, and Anxiety subscales of the Achievement Emotions Questionnaire and the Maslach Burnout Inventory (MBI) General Survey for Students were administered in fall 2017. Academic performance (semester overall percentage) was matched to participants completing all 4 questionnaires. Descriptive and inferential statistics were used to analyze the results. Findings: Response rates for those who completed every survey administered was 18.5%. Combined data from the classes revealed relationships between academic performance with MBI subscale-professional efficacy (r = .577), hope (r = .497), pride (r = .411), anxiety (r = −.307), and shame (r = −.402). Upon analyzing data from each class, professional efficacy (M1: r = .535; M2: r = .674) and pride (M1: r = .591; M2: r = .450) were correlated to academic performance. In a stepwise regression model, professional efficacy was the only predictor of academic performance (B = .560, t = 3.82, R2 = .31). Insights: When faced with challenges from medical school, positive emotions strengthen self-efficacy, allowing students to identify strategies to accomplish academic goals. Although it is important to acknowledge the emotions that students experience, our finding that professional efficacy was the most significant predictor of academic performance suggests the need for strategies to enhance self-efficacy. Use of flipped classrooms or problem-based learning offers opportunities for cognitive appraisal to foster their self-efficacy

Rancière and the poetics of the social sciences

This article reviews the significance of Jacques Rancière’s work for methodological debates in the social sciences, and education specifically. It explores the implications of framing methodology as an aesthetic endeavour, rather than as the applied technique of research. What is at stake in this distinction is the means by which research intervenes in social order and how it assumes political significance, with Rancière arguing against a notion of science as the other of ideology. Rancière’s argument for a democratic research practice organised around a ‘method of equality’ is situated in relation to openly ideological’ feminist ethnography. The implications of Rancière’s work for investigating affect in academic discourse and subjectification in education are reviewed in the conclusion

Potential and Pitfalls of Prescribed Burning Big Sagebrush Habitat to Enhance Nesting and Early Brood-Rearing Habitats for Greater Sage-Grouse

We describe short-term (≤10 yrs) and long-term (\u3e10 yrs) responses of prescribed burning to enhance nesting and early brood-rearing habitat for greater sage-grouse (Centrocercus urophasianus). Our primary objective was to provide a literature synthesis to identify short- and long-term responses of prescribed burning to important components of sage-grouse nesting and early brood-rearing habitats in mountain (Artemisia tridentata vaseyana) and Wyoming (A. t. wyomingensis) big sagebrush. In our synthesis, we evaluated ecological status (bare ground and litter), food availability (forbs and insects), and vegetation structure (grass and sagebrush cover). We used six criteria to identify n = 12 papers providing meaningful and rigorous results. Of these papers, six reported the effects of burning in mountain big sagebrush; seven in Wyoming big sagebrush; and one provided information for mountain and Wyoming big sagebrush. Our findings point to some potential for short-term enhancement of forbs and grasses in mountain big sagebrush, but no long-term enhancement of herbs in mountain big sagebrush or short- or long-term enhancement of herbs in Wyoming big sagebrush. In particular, prescribed burning leads to a pronounced negative response in sagebrush cover that lasts for at least a few decades. Based on our findings, we cannot recommend burning Wyoming big sagebrush to enhance sage-grouse nesting or early brood-rearing habitat and we suggest prescribed burning has limited short-term value in enhancing forbs and grasses for sage-grouse inhabiting Mountain big sagebrush

Effects of CO2 and H2S on corrosion of martensitic steels in brines at low temperature

Corrosion studies were conducted for martensitic carbon steels in 5 wt% NaCl brine solutions at 4°C and 10 MPa (1,450 psi). These studies simulated different subsurface environments relevant to Arctic drilling. Here, two high-strength martensitic carbon steels, S-135 and UD-165, were studied in three different environments: (1) a CO2-NaCl-H2O solution with a CO2:H2O molar ratio of 0.312 in the whole system, (2) an H2SNaCl- H2O solution with an H2S:H2O molar ratio of 3.12 × 10−4, and (3) a CO2-H2S-NaCl-H2O solution with the same acid gas to water ratios as environments 1 and 2. Results from the CO2+H2S mixed environment indicated that sour corrosion mechanism was dominant when the CO2:H2S molar ratio was 1,000. This impact of a small amount of H2S on the corrosion mechanism could be attributed to the specific adsorption of H2S on the steel surface. Electrochemical and mass loss measurements showed a distinct drop in the corrosion rate (CR) by more than one order of magnitude when transitioning from sweet to sour corrosion. This inhibiting effect on CR was attributed to the formation of a protective sulfide thin film

Citizen forecasting suggests Macron will win a comfortable victory over Marine Le Pen

With the second round of the French presidential election just days away, what can election forecasts tell us about the likely result? Drawing on a citizen forecasting model, Andreas Murr, Yannick Dufresne, Justin Savoie, Bruno Jérôme and Michael S. Lewis-Beck write that Emmanuel Macron looks set to win a comfortable victory over Marine Le Pen

Global analysis of seasonal streamflow predictability using an ensemble prediction system and observations from 6192 small catchments worldwide

Key Points Global bimonthly streamflow forecasts show potentially valuable skill Initial catchment conditions are responsible for most skill Skill can be estimated from model performance and theoretical skill Ideally, a seasonal streamflow forecasting sy

Corrosion behavior of 13Cr casing steel in cement-synthetic pore solution exposed to high pressure CO2 and H2S

The electrochemical corrosion behavior of grade L-80, type 13Cr casing steel was investigated in cement-synthetic pore solution (CSPS) exposed to CO2 and H2S using in-situ electrochemical methods and ex-situ surface analyses at 85 and 200 °C, respectively. Total system pressure was 10 MPa. Corrosion rates increased significantly when the temperature increased from 85 to 200 °C. Limiting current behavior was observed for the anode reaction, while charge-transfer control was observed for the cathode reaction. Surface analyses revealed the presence of CaCO3 on the surface at both temperatures and FeCO3-like deposits at 200 °C

The impact of obesity on the immune response to infection

There is strong evidence indicating that excess adiposity negatively impacts immune function and host defence in obese individuals. This is a review of research findings concerning the impact of obesity on the immune response to infection, including a discussion of possible mechanisms. Obesity is characterised by a state of low-grade, chronic inflammation in addition to disturbed levels of circulating nutrients and metabolic hormones. The impact of these metabolic abnormalities on obesity-related comorbidities has undergone intense scrutiny over the past decade. However, relatively little is known of how the immune system and host defence are influenced by the pro-inflammatory and excess energy milieu of the obese. Epidemiological data suggest obese human subjects are at greater risk for nosocomial infections, especially following surgery. Additionally, the significance of altered immunity in obese human subjects is emphasised by recent studies reporting obesity to be an independent risk factor for increased morbidity and mortality following infection with the 2009 pandemic influenza A (H1N1) virus. Rodent models offer important insight into how metabolic abnormalities associated with excess body weight can impair immunity. However, more research is necessary to understand the specific aspects of immunity that are impaired and what factors are contributing to reduced immunocompetence in the obese. Additionally, special consideration of how infection in this at-risk population is managed is required, given that this population may not respond optimally to antimicrobial drugs and vaccination. Obesity impacts millions globally, and greater understanding of its associated physiological disturbances is a key public health concern

A path integral approach to the dynamics of a random chain with rigid constraints

In this work the dynamics of a freely jointed random chain which fluctuates at constant temperature in some viscous medium is studied. The chain is regarded as a system of small particles which perform a brownian motion and are subjected to rigid constraints which forbid the breaking of the chain. For simplicity, all interactions among the particles have been switched off and the number of dimensions has been limited to two. The problem of describing the fluctuations of the chain in the limit in which it becomes a continuous system is solved using a path integral approach, in which the constraints are imposed with the insertion in the path integral of suitable Dirac delta functions. It is shown that the probability distribution of the possible conformations in which the fluctuating chain can be found during its evolution in time coincides with the partition function of a field theory which is a generalization of the nonlinear sigma model in two dimensions. Both the probability distribution and the generating functional of the correlation functions of the positions of the beads are computed explicitly in a semiclassical approximation for a ring-shaped chain.Comment: 36 pages, 2 figures, LaTeX + REVTeX4 + graphicx, minor changes in the text, reference adde