Some effects of meteorological processes on the air quality in Medford, Oregon

In Medford, Oregon, the major source of pollution is the lumber mill waste burner. Its low combustion efficiency results in the emission of large quantities of particulate into the atmosphere. Due to the influence of the atmospheric radiation inversion and possibly the poor performance of the burners at the time of start-up, concentrations of particulate were found to be highest in the morning. Correlating these morning concentrations with average surface relative humidity, average surface wind speed, and various stability indices, most of which were determined from the U.S. Weather Bureau's 0300 PST radiosonde release, provided a measure of the degree of relationship between these meteorological factors and pollution. In addition, the analysis resulted in a determination of what stability factors could readily be used to predict pollution concentrations with reasonable accuracy (correlation coefficients ≥ 0.65). These included the sounding energy to 850 mb (energy required to lift a parcel of air from surface to 850 mb), the temperature difference index (difference in temperature between 850 mb and surface), the Modified Showalter Stability Index (Showalter Index applied to the layer of air between surface and 850 mb), and the persistence index (the sum of three weighted Modified Showalter Index values for three consecutive mornings). Graphical and regression prediction models involving the persistence index and average surface wind speed were developed. These relationships proved to be more accurate in predicting morning concentrations of particulate (multiple correlation coefficients 0.84) than those involving only one meteorological variable (highest correlation coefficient = 0.74). In order to illustrate the effects of air pollution on visibility, a preliminary relationship between concentrations of suspended particulate and visibility was developed. If visibility were selected as the criterion for judging air quality as it might well be in a tourist-oriented economy, such a relationship could serve as the basis for forecasting conditions of unacceptably low visibility as a result of high concentrations

Estimating survival of precocial chicks during the prefledging period using a catch-curve analysis and count-based age-class data

ABSTRACT: Estimating reproductive success for birds with pre-cocial young can be difficult because chicks leave nests soon after hatching and individuals or broods can be difficult to track. Researchers often turn to estimating survival during the pre-fledging period and, though effective, mark-recapture based approaches are not always feasible due to cost, time, and animal welfare concerns. Using a threatened population of Piping Plovers (Charadrius melodus) that breeds along the Missouri River, we present an approach for estimating chick survival during the pre-fledging period using long-term (1993–2005), count-based, age-class data. We used a modified catch-curve analysis, and data collected during three 5-day sampling periods near the middle of the breeding season. The approach has several ecological and statistical assumptions and our analyses were designed to minimize the probability of violating those assumptions. For example, limiting the sampling periods to only 5 days gave reasonable assurance that population size was stable during the sampling period. Annual daily survival estimates ranged from 0.825 (SD = 0.03) to 0.931 (0.02) depending on year and sampling period, with these estimates assuming constant survival during the pre-fledging period and no change in the age structure of the population. The average probability of survival to fledging ranged from 0.126 to 0.188. Our results are similar to other published estimates for this species in similar habitats. This method of estimating chick survival may be useful for a variety of pre-cocial bird species when mark-recapture methods are not feasible and only count-based age class data are available. RESUMEN. La estimaci´on de la supervivencia de polluelos precociales durante el periodo pre-volant´on usando un an´alisis de curva de captura y datos con clases de edades basados en conteos Estimar el ´exito reproductivo de aves con polluelos precociales puede ser dif´ıcil debido a que los polluelos dejan el nido poco despu´es de eclosionar y los individuos o nidadas pueden ser dif´ıciles de seguir. Los investigadores a menudo estiman la supervivencia durante el periodo pre-volant´on y aunque son efectivos, los m´etodos de marcaje y recaptura no son siempre factibles por razones del costo, tiempo y bienestar del animal. Usando una poblaci´on amenazada de Charadrius melodus que se reproduce sobre el R´ıo Missouri, presentamos un m´etodo para estimar la supervivencia de polluelos durante el periodo pre-volant´on usando datos de largo plazo (1993–2005) con clases de edades, basados en conteos. Utilizamos un an´alisis de curva de captura modificada y datos colectados durante tres periodos de muestreo de cinco d´ıas cada uno, cerca del medio de la ´epoca reproductiva. Este m´etodo tiene algunos supuestos ecol´ogicos y estad´ısticos y nuestros an´alisis fueron dise˜nados para minimizar la probabilidad de violar dichos supuestos. Por ejemplo, limitando los periodos de muestreo a solo cinco d´ıas dio el resultado razonable de que el tama˜no de la poblaci´on fue estable durante el periodo de muestreo. Las estimaciones de la supervivencia diaria anual variaron entre 0.825 (DE = 0.03) y 0.931 (0.02), dependiendo del a˜no y periodo de muestreo. Estas estimaciones dependieron de la suposici´on de una supervivencia constante durante el periodo pre-volant´on y de ning´un cambio en la estructura de la edad de la poblaci´on. El promedio de la probabilidad de supervivencia en la etapa pre-volant´on vari´o desde 0.126 hasta 0.188. Nuestros resultados son similares a otras estimaciones publicadas para esta especie en h´abitats similares. Este m´etodo de estimar la supervivencia de los polluelos podr´ıa ser ´util para una variedad de especies de aves precociales cuando los m´etodos de marcaje y recaptura no son factibles y cuando solo est´an disponibles datos con clases de edades basados en conteos

Commentary: osteoarthritis of the knee and glucosamine

peer reviewe

Quantitative copper measurement in oxidized p-type silicon wafers using microwave photoconductivity decay

We propose a method to measure trace copper contamination in p-type silicon using the microwave photoconductivity decay (μ-PCD) technique. The method is based on the precipitation of interstitial copper, activated by high-intensity light, which results in enhanced minority carrier recombination activity. We show that there is a quantitative correlation between the enhanced recombination rate and the Cu concentration by comparing μ-PCD measurements with transient ion drift and total reflection x-ray fluorescence measurements. The results indicate that the method is capable of measuring Cu concentrations down to 10exp10cm−3. There are no limitations to wafer storage time if corona charge is used on the oxidized wafer surfaces as the charge prevents copper outdiffusion. We briefly discuss the role of oxide precipitates both in the copperprecipitation and in the charge carrier recombination processes.Peer reviewe

beta-Lactamase can function as a reporter of bacterial protein export during Mycobacterium tuberculosis infection of host cells

Mycobacterium tuberculosis is an intracellular pathogen that is able to avoid destruction by host immune defenses. Exported proteins of M. tuberculosis, which include proteins localized to the bacterial surface or secreted into the extracellular environment, are ideally situated to interact with host factors. As a result, these proteins are attractive candidates for virulence factors, drug targets, and vaccine components. Here we describe a new β-lactamase reporter system capable of identifying exported proteins of M. tuberculosis during growth in host cells. Because β-lactams target bacterial cell wall synthesis, β-lactamases must be exported beyond the cytoplasm to protect against these drugs. When used in protein fusions, β-lactamase can report on the subcellular location of another protein as measured by protection from β-lactam antibiotics. Here we demonstrate that a truncated TEM-1 β-lactamase lacking a signal sequence for export (‘BlaTEM-1) can be used in this manner directly in a mutant strain of M. tuberculosis lacking the major β-lactamase, BlaC. The ‘BlaTEM-1 reporter conferred β-lactam resistance when fused to both Sec and Tat export signal sequences. We further demonstrate that β-lactamase fusion proteins report on protein export while M. tuberculosis is growing in THP-1 macrophage-like cells. This genetic system should facilitate the study of proteins exclusively exported in the host environment by intracellular M. tuberculosis

The transition between stochastic and deterministic behavior in an excitable gene circuit

We explore the connection between a stochastic simulation model and an ordinary differential equations (ODEs) model of the dynamics of an excitable gene circuit that exhibits noise-induced oscillations. Near a bifurcation point in the ODE model, the stochastic simulation model yields behavior dramatically different from that predicted by the ODE model. We analyze how that behavior depends on the gene copy number and find very slow convergence to the large number limit near the bifurcation point. The implications for understanding the dynamics of gene circuits and other birth-death dynamical systems with small numbers of constituents are discussed.Comment: PLoS ONE: Research Article, published 11 Apr 201

Education as Risk Factor of Mild Cognitive Impairment:The Link to the Gut Microbiome

Background: With differences apparent in the gut microbiome in mild cognitive impairment (MCI) and dementia, and risk factors of dementia linked to alterations of the gut microbiome, the question remains if gut microbiome characteristics may mediate associations of education with MCI. Objectives: We sought to examine potential mediation of the association of education and MCI by gut microbiome diversity or composition. Design: Cross-sectional study. Setting: Luxembourg, the Greater Region (surrounding areas in Belgium, France, Germany). Participants: Control participants of the Luxembourg Parkinson’s Study. Measurements: Gut microbiome composition, ascertained with 16S rRNA gene amplicon sequencing. Differential abundance, assessed across education groups (0–10, 11–16, 16+ years of education). Alpha diversity (Chao1, Shannon and inverse Simpson indices). Mediation analysis with effect decomposition was conducted with education as exposure, MCI as outcome and gut microbiome metrics as mediators. Results: After exclusion of participants below 50, or with missing data, n=258 participants (n=58 MCI) were included (M [SD] Age=64.6 [8.3] years). Higher education (16+ years) was associated with MCI (Odds ratio natural direct effect=0.35 [95% CI 0.15–0.81]. Streptococcus and Lachnospiraceae-UCG-001 genera were more abundant in higher education. Conclusions: Education is associated with gut microbiome composition and MCI risk without clear evidence for mediation. However, our results suggest signatures of the gut microbiome that have been identified previously in AD and MCI to be reflected in lower education and suggest education as important covariate in microbiome studies

Age at onset as stratifier in idiopathic Parkinson's disease - effect of ageing and polygenic risk score on clinical phenotypes

Several phenotypic differences observed in Parkinson's disease (PD) patients have been linked to age at onset (AAO). We endeavoured to find out whether these differences are due to the ageing process itself by using a combined dataset of idiopathic PD (n = 430) and healthy controls (HC; n = 556) excluding carriers of known PD-linked genetic mutations in both groups. We found several significant effects of AAO on motor and non-motor symptoms in PD, but when comparing the effects of age on these symptoms with HC (using age at assessment, AAA), only positive associations of AAA with burden of motor symptoms and cognitive impairment were significantly different between PD vs HC. Furthermore, we explored a potential effect of polygenic risk score (PRS) on clinical phenotype and identified a significant inverse correlation of AAO and PRS in PD. No significant association between PRS and severity of clinical symptoms was found. We conclude that the observed non-motor phenotypic differences in PD based on AAO are largely driven by the ageing process itself and not by a specific profile of neurodegeneration linked to AAO in the idiopathic PD patients

Prognostic factors for abatacept retention in patients who received at least one prior biologic agent: an interim analysis from the observational, prospective ACTION study

Background: The emergence of new therapies for the treatment of rheumatoid arthritis (RA), the paucity of head-to-head studies, and the heterogeneous nature of responses to current biologics highlight the need for the identification of prognostic factors for treatment response and retention in clinical practice. Prognostic factors for patient retention have not been explored thoroughly despite data for abatacept and other biologics being available from national registries. Real-world data from the ACTION study may supplement the findings of randomized controlled trials and show how abatacept is used in clinical practice. The aim of this interim analysis was to identify prognostic factors for abatacept retention in patients with RA who received at least one prior biologic agent. Methods: A large, international, non-interventional cohort of patients with moderate-to-severe RA who initiated intravenous abatacept in Canada and Europe (May 2008–January 2011) enrolled in the ACTION study. Potential prognostic factors for retention in this interim analysis (data cut-off February 2012; including patients from Canada, Germany, Greece, and Italy) were baseline demographics and disease characteristics, medical history, and previous and concomitant medication. Clinically relevant variables with p ≤ 0.20 in univariate analysis and no collinearity were entered into a Cox proportional hazards regression model, adjusted for clustered data. Variables with p ≤ 0.10 were retained in the final model (backward selection). Results: The multivariate model included 834 patients. Anti-cyclic citrullinated peptide (CCP) antibody positivity (hazard ratio [95 % confidence interval]: 0.55 [0.40, 0.75], p < 0.001), failure of <2 prior anti-tumor necrosis factors (TNFs) (0.71 [0.56, 0.90], p = 0.005 versus ≥2 prior anti-TNFs), and cardiovascular comorbidity at abatacept initiation (0.48 [0.28, 0.83], p = 0.009) were associated with lower risk of abatacept discontinuation. Patients in Greece and Italy were less likely to discontinue abatacept than patients in Germany and Canada (Greece: 0.30 [0.16, 0.58]; Italy: 0.50 [0.33, 0.76]; Canada: 1.04 [0.78, 1.40], p < 0.001 versus Germany). Conclusions: Real-world prognostic factors for abatacept retention include anti-CCP positivity and fewer prior anti-TNF failures. Differences in retention rates between countries may reflect differences in healthcare systems. The finding that abatacept has potential advantages in patients with cardiovascular comorbidities needs to be confirmed in further research