Polarization and Extent of Maser Emission from Late-Type Stars: Support for a Plasma Turbulence Model of Maser Production

The integrated spectrum of OH emission from late-type stars is often circularly polarized, by as much as 50% in some cases. While the spectra are partially polarized, the individual maser components revealed by VLBI are much more so. Using VLBI observations of late-type stars from the literature, we show that the difference in circular polarization between main lines correlates with a difference in angular extent for a given object. This is a natural result if turbulent magnetic fields are causing the masers to be polarized via the Cook mechanism, and might serve as a good diagnostic for determining which objects should be investigated in the search for magnetic fields around evolved stars.Comment: 5 pages, 2 figs ApJL, accepte

Peak inspiratory flow through Diskus and Turbuhaler, measured by means of a peak inspiratory flow meter (In-Check DIAL®)

AbstractWith a handheld peak inspiratory flow (PIF) meter (In-Check DIAL®), the internal resistance of the Diskus® (DKR) and the Turbuhaler® (THR) can be simulated by means of calibrated resistances. This study investigated whether patients with asthma or chronic obstructive pulmonary disease could generate a PIF which is optimal for the Diskus (DK) (30 l/min) and the Turbuhaler (TH) (60 l/min). Peak expiratory flow (PEF) and maximal inspiratory pressure (MIP) were also assessed. All 50 patients (30 males, mean age 56.9) achieved the required flow of 30 l/min with the DKR, while six patients (five females) could not generate the optimal flow of 60 l/min via the THR. Analysis showed that MIP was an independent predictor of an adequate PIF through the THR. During the study, eight patients were treated for an exacerbation of which four could not generate an adequate PIF via the THR. Analysis showed that the female gender and an exacerbation appeared to be independent predictors of the inability to generate an adequate PIF via the THR. Twelve per cent of patients (25% of females) could not generate the optimal inspiratory flow via the THR. When in doubt whether the patient can generate an adequate inspiration, measurement with the In-Check DIAL® is recommended

Relationship between infarct tissue characteristics and left ventricular remodeling in patients with versus without early revascularization for acute myocardial infarction as assessed with contrast-enhanced cardiovascular magnetic resonance imaging

Left ventricular (LV) remodeling following myocardial infarction (MI) is the result of complex interactions between various factors, including presence or absence of early revascularization. The impact of early revascularization on the relationship between infarct tissue characteristics and LV remodeling is incompletely known. Therefore, we investigated in patients with versus without successful early revascularization for acute MI potential relations between infarct tissue characteristics and LV remodeling with contrast-enhanced (CE) cardiovascular magnetic resonance (CMR). Patients with versus without successful early revascularization underwent CE-CMR for tissue characterization and assessment of LV remodeling including end-diastolic and end-systolic volumes, LV ejection fraction, and wall motion score index (WMSI). CE-CMR images were analyzed for infarct tissue characteristics including core-, peri- and total-infarct size, transmural extent, and regional scar scores. In early revascularized patients (n = 46), a larger area of infarct tissue correlated significantly with larger LV dimensions and a more reduced LV function (r = 0.39-0.68; all P ≤ 0.01). Multivariate analyses identified peri-infarct size as the best predictor of LV remodeling parameters (R2 = 0.44-0.62). In patients without successful early revascularization (n = 47), there was no correlation between infarct area and remodeling parameters; only peri-infarct size versus WMSI (r = 0.33; P = 0.03) and transmural extent versus LVEF (r = -0.27; P = 0.07) tended to be related. A correlation between infarct tissue characteristics and LV remodeling was found only in patients with early successful revascularization. Peri-infarct size was found to be the best determinant of LV remodeling. Our findings stress the importance of taking into account infarct tissue characteristics and success of revascularization when LV remodeling is studie

Mixture randomized item-response modeling:a smoking behavior validation study

Misleading response behavior is expected in medical settings where incriminating behavior is negatively related to the recovery from a disease. In the present study, lung patients feel social and professional pressure concerning smoking and experience questions about smoking behavior as sensitive and tend to conceal embarrassing or threatening information. The randomized item-response survey method is expected to improve the accuracy of self-reports as individual item responses are masked and only randomized item responses are observed. We explored the validation of the randomized item-response technique in a unique experimental study. Therefore, we administered a new multi-item measure assessing smoking behavior by using a treatment–control design (randomized response (RR) or direct questioning). After the questionnaire, we administered a breath test by using a carbon monoxide (CO) monitor to determine the smoking status of the patient. We used the response data to measure the individual smoking behavior by using a mixture item-response model. It is shown that the detected smokers scored significantly higher in the RR condition compared with the directly questioned condition. We proposed a Bayesian latent variable framework to evaluate the diagnostic test accuracy of the questionnaire using the randomized-response technique, which is based on the posterior densities of the subject's smoking behavior scores together with the breath test measurements. For different diagnostic test thresholds, we obtained moderate posterior mean estimates of sensitivity and specificity by observing a limited number of discrete randomized item response

Infarct tissue characterization in implantable cardioverter-defibrillator recipients for primary versus secondary prevention following myocardial infarction: a study with contrast-enhancement cardiovascular magnetic resonance imaging

Knowledge about potential differences in infarct tissue characteristics between patients with prior life-threatening ventricular arrhythmia versus patients receiving prophylactic implantable cardioverter-defibrillator (ICD) might help to improve the current risk stratification in myocardial infarction (MI) patients who are considered for ICD implantation. In a consecutive series of (ICD) recipients for primary and secondary prevention following MI, we used contrast-enhanced (CE) cardiovascular magnetic resonance (CMR) imaging to evaluate differences in infarct tissue characteristics. Cine-CMR measurements included left ventricular end-diastolic and end-systolic volumes (EDV, ESV), left ventricular ejection fraction (LVEF), wall motion score index (WMSI), and mass. CE-CMR images were analyzed for core, peri, and total infarct size, infarct localization (according to coronary artery territory), and transmural extent. In this study, 95 ICD recipients were included. In the primary prevention group (n = 66), LVEF was lower (23 ± 9 % vs. 31 ± 14 %; P < 0.01), ESV and WMSI were higher (223 ± 75 ml vs. 184 ± 97 ml, P = 0.04, and 1.89 ± 0.52 vs. 1.47 ± 0.68; P < 0.01), and anterior infarct localization was more frequent (P = 0.02) than in the secondary prevention group (n = 29). There were no differences in infarct tissue characteristics between patients treated for primary versus secondary prevention (P > 0.6 for all). During 21 ± 9 months of follow-up, 3 (5 %) patients in the primary prevention group and 9 (31 %) in the secondary prevention group experienced appropriate ICD therapy for treatment of ventricular arrhythmia (P < 0.01). There was no difference in infarct tissue characteristics between recipients of ICD for primary versus secondary prevention, while the secondary prevention group showed a higher frequency of applied ICD therapy for ventricular arrhythmia.\u

Amphibian Species’ Traits, Evolutionary History, and Environment Predict Batrachochytrium Dendrobatidis Infection Patterns, but not Extinction Risk

The fungal pathogen Batrachochytrium dendrobatidis (B. dendrobatidis) has emerged as a major agent of amphibian extinction, requiring conservation intervention for many susceptible species. Identifying susceptible species is challenging, but many aspects of species biology are predicted to influence the evolution of host resistance, tolerance, or avoidance strategies towards disease. In turn, we may expect species exhibiting these distinct strategies to differ in their ability to survive epizootic disease outbreaks. Here, we test for phylogenetic and trait-based patterns of B. dendrobatidis infection risk and infection intensity among 302 amphibian species by compiling a global data set of B. dendrobatidis infection surveys across 95 sites. We then use best-fit models that associate traits, taxonomy and environment with B. dendrobatidis infection risk and intensity to predict host disease mitigation strategies (tolerance, resistance, avoidance) for 122 Neotropical amphibian species that experienced epizootic B. dendrobatidis outbreaks, and noted species persistence or extinction from these events. Aspects of amphibian species life history, habitat use and climatic niche were consistently linked to variation in B. dendrobatidis infection patterns across sites around the world. However, predicted B. dendrobatidis infection risk and intensity based on site environment and species traits did not reveal a consistent pattern between the predicted host disease mitigation strategy and extinction outcome. This suggests that either tolerant or resistant species may have no advantage in ameliorating disease during epizootic events, or that other factors drive the persistence of amphibian populations during chytridiomycosis outbreaks. These results suggest that using a trait-based approach may allow us to identify species with resistance or tolerance to endemic B. dendrobatidis infections, but that this approach may be insufficient to ultimately identify species at risk of extinction from epizootics

O efeito da descontinuação dos corticóides inalados em doentes com Doença Pulmonar Obstrutiva Crónica — O estudo COPE

RESUMO: Os autores desenharam um estudo duplamente cego para investigar o efeito da descontinuação do propionato de fluticasona (PF) nas exacerbações e qualidade de vida em doentes com DPOC (estudo COPE).Durante 4 meses, 244 doentes com DPOC foram medicados com propionato de fluticasona (1000 (g /dia).A selecção dos doentes baseou se em critérios clínicos e funcionais e idade compreendida entre os 40 e os 75 anos. Após este período de tempo, 123 doentes mantiveram o tratamento com PF e 121 doentes receberam placebo durante 6 meses. As visitas de controlo ocorreram aos 3 e 6 meses, tendo os doentes sido avaliados do ponto de vista funcional e clínico. Os critérios analisados no estudo foram o número, gravidade e intervalo de tempo entre as exacerbações, a qualidade de vida (questionário respiratório de St Georgeâs), parâmetros funcionais respiratórios (espirometria) e tolerância ao esforço (prova de 6 minutos de marcha standardizada).Na análise dos resultados, os autores demonstraram que no grupo medicado com PF, 47% dos doentes sofreram pelo menos uma agudização, em contraste dos 57 % do grupo placebo. No grupo placebo, 21 % dos doentes apresentaram exacerbações recorrentes e rápidas, ao contrário dos 6% de doentes medicados com PF. Em termos de qualidade de vida, uma diferença significativa ocorreu também entre os 2 grupos, a nível do score total, actividade e sintomas.Não se verificaram diferenças na prova de marcha entre os 2 grupos avaliados. O estudo funcional mostrou uma diferença significativa de 38 ml de VEMS pós-broncodilatação, a favor do grupo medicado com FP.Este estudo indica que a descontinuação de PF em doentes com DPOC está associada a um mais rápido início e recorrência de agudização, bem como uma deterioração maior da qualidade de vida. COMENTÃRIO: Estima-se que a DPOC constitua a 5.ª doença mais frequente e a 4.ª causa de morte a nível mundial.Não existindo cura para esta doença, a terapêutica assenta fundamentalmente na broncodilatação e na evicção tabágica.Sabe se que apesar de a DPOC ser uma doença inflamatória crónica das vias aéreas, os corti cóides inalados (CI) não modificam o declínio mais acelerado do VEMS constatado na DPOC.Múltiplos estudos foram efectuados tendo como um dos objectivos determinar a validade da utilização de CI na DPOC, dos quais se salienta:O estudo EUROSCOP revela eficácia reduzida e transitória do budesonido; o estudo ISOLDE mostrou uma pequena redução no declínio do VEMS, um menor número de exacerbações e score sintomático, em doentes com DPOC grave tratados com fluticasona e o estudo COPENHAGEN não demonstrou qualquer beneficio do budesonido na DPOC ligeira e moderada.O projecto GOLD considera os CI como fármacos de 2.ª linha no tratamento da DPOC, mas refere também uma melhoria sintomática, uma redução no número e gravidade das exacerbações e melhoria da qualidade de vida.Este estudo vem exactamente reforçar o efeito benéfico dos CI em doentes com DPOC a nível da qualidade de vida e frequência e gravidade das agudizações, assim como o agravamento destes parâmetros após a suspensão dos CI. Palavras-chave: Corticóides inalados, DPOC, Qualidade de vida, Exacerbaçã