Age distributions of star clusters in spiral and barred galaxies as a test for theories of spiral structure

We consider models of gas flow in spiral galaxies in which the spiral structure has been excited by various possible mechanisms: a global steady density wave, self-gravity of the stellar disc and an external tidal interaction, as well as the case of a galaxy with a central rotating bar. In each model we estimate in a simple manner the likely current positions of star clusters of a variety of ages, ranging from ~ 2 Myr to around 130 Myr, depending on the model. We find that the spatial distribution of cluster of different ages varies markedly depending on the model, and propose that observations of the locations of age-dated stellar clusters is a possible discriminant between excitation mechanisms for spiral structure in an individual galaxy.Comment: 10 pages, 4 figures, accepted for publication in MNRA

Acute Cardiovascular Effects of Controlled Exposure to Dilute Petrodiesel and Biodiesel Exhaust in Healthy Volunteers: A Crossover Study

Abstract Background Air pollution derived from combustion is associated with considerable cardiorespiratory morbidity and mortality in addition to environmental effects. Replacing petrodiesel with biodiesel may have ecological benefits, but impacts on human health remain unquantified. The objective was to compare acute cardiovascular effects of blended and pure biodiesel exhaust exposure against known adverse effects of petrodiesel exhaust (PDE) exposure in human subjects. In two randomized controlled double-blind crossover studies, healthy volunteers were exposed to PDE or biodiesel exhaust for one hour. In study one, 16 subjects were exposed, on separate occasions, to PDE and 30% rapeseed methyl ester biodiesel blend (RME30) exhaust, aiming at PM10 300 μg/m3. In study two, 19 male subjects were separately exposed to PDE and exhaust from a 100% RME fuel (RME100) using similar engine load and exhaust dilution. Generated exhaust was analyzed for physicochemical composition and oxidative potential. Following exposure, vascular endothelial function was assessed using forearm venous occlusion plethysmography and ex vivo thrombus formation was assessed using a Badimon chamber model of acute arterial injury. Biomarkers of inflammation, platelet activation and fibrinolysis were measured in the blood. Results In study 1, PDE and RME30 exposures were at comparable PM levels (314 ± 27 μg/m3; (PM10 ± SD) and 309 ± 30 μg/m3 respectively), whereas in study 2, the PDE exposure concentrations remained similar (310 ± 34 μg/m3), but RME100 levels were lower in PM (165 ± 16 μg/m3) and PAHs, but higher in particle number concentration. Compared to PDE, PM from RME had less oxidative potential. Forearm infusion of the vasodilators acetylcholine, bradykinin, sodium nitroprusside and verapamil resulted in dose-dependent increases in blood flow after all exposures. Vasodilatation and ex vivo thrombus formation were similar following exposure to exhaust from petrodiesel and the two biodiesel formulations (RME30 and RME100). There were no significant differences in blood biomarkers or exhaled nitric oxide levels between exposures. Conclusions Despite differences in PM composition and particle reactivity, controlled exposure to biodiesel exhaust was associated with similar cardiovascular effects to PDE. We suggest that the potential adverse health effects of biodiesel fuel emissions should be taken into account when evaluating future fuel policies. Trial registration ClinicalTrials.gov, NCT01337882 /NCT01883466. Date of first enrollment March 11, 2011, registered April 19, 2011, i.e. retrospectively registered

Photocatalytic Decomposition of Formic Acid on Mo2C-Containing Catalyst

Soluble components in the peripheral blood from experimental exposure of 14 healthy subjects to filtered air and wood smoke. Samples were collected before (pre), at 24 h and 44 h after exposure, to air and wood smoke. Data are given as medians with interquartile range. (DOCX 62 kb

Digit Ratio Predicts Sense of Direction in Women

The relative length of the second-to-fourth digits (2D:4D) has been linked with prenatal androgen in humans. The 2D:4D is sexually dimorphic, with lower values in males than females, and appears to correlate with diverse measures of behavior. However, the relationship between digit ratio and cognition, and spatial cognition in particular, has produced mixed results. In the present study, we hypothesized that spatial tasks separating cue conditions that either favored female or male strategies would examine this structure-function correlation with greater precision. Previous work suggests that males are better in the use of directional cues than females. In the present study, participants learned a target location in a virtual landscape environment, in conditions that contained either all directional (i.e., distant or compass bearing) cues, or all positional (i.e., local, small objects) cues. After a short delay, participants navigated back to the target location from a novel starting location. Males had higher accuracy in initial search direction than females in environments with all directional cues. Lower digit ratio was correlated with higher accuracy of initial search direction in females in environments with all directional cues. Mental rotation scores did not correlate with digit ratio in either males or females. These results demonstrate for the first time that a sex difference in the use of directional cues, i.e., the sense of direction, is associated with more male-like digit ratio.National Science Foundation (U.S.) (NSF ECCS-1028319)National Science Foundation (U.S.) (NSF Graduate Student Fellowship)Mary Elisabeth Rennie Endowment for Epilepsy Researc

Investing in Localized Relationships with Universities: What are the Benefits for R&D Subsidiaries of Multinational Enterprises?

In spite of a long-standing interest in the distribution of knowledge spillovers from university research, there is only limited theoretical understanding of if and when opportunities to interact with a research university constitute a significant force of attraction for globally mobile investment in R&D. Based on an empirical investigation of the benefits of interaction with universities, this paper proposes an analytical framework and four ideal types of strategy for localised collaboration between R&D subsidiaries and universities. This taxonomy, which largely transcends industry sectors, and the illustrative cases presented in this paper provide insights into the potential scope for localised university-industry interaction from the perspective of multinational enterprises. By connecting the empirical results to the question whether these benefits are significant enough to enhance a region's attractiveness as a location for R&D, we are able to develop a better understanding of the alternative strategies for policymakers and university leaders interested in stimulating such linkages.Knowledge spillovers, multinational enterprises, university-industry interaction, localisation of R&D,

Experimental determination of the respiratory tract deposition of diesel combustion particles in patients with chronic obstructive pulmonary disease

Background: Air pollution, mainly from combustion, is one of the leading global health risk factors. A susceptible group is the more than 200 million people worldwide suffering from chronic obstructive pulmonary disease (COPD). There are few data on lung deposition of airborne particles in patients with COPD and none for combustion particles. Objectives: To determine respiratory tract deposition of diesel combustion particles in patients with COPD during spontaneous breathing. Methods: Ten COPD patients and seven healthy subjects inhaled diesel exhaust particles generated during idling and transient driving in an exposure chamber. The respiratory tract deposition of the particles was measured in the size range 10-500 nm during spontaneous breathing. Results: The deposited dose rate increased with increasing severity of the disease. However, the deposition probability of the ultrafine combustion particles (< 100 nm) was decreased in COPD patients. The deposition probability was associated with both breathing parameters and lung function, but could be predicted only based on lung function. Conclusions: The higher deposited dose rate of inhaled air pollution particles in COPD patients may be one of the factors contributing to their increased vulnerability. The strong correlations between lung function and particle deposition, especially in the size range of 20-30 nm, suggest that altered particle deposition could be used as an indicator respiratory disease

The phenotype of concurrent chronic bronchitis and frequent exacerbations in patients with severe COPD attending Swedish secondary care units

Background: Chronic bronchitis and previous exacerbations are both well-known risk factors for new exacerbations, impaired health-related quality of life, and increased mortality in COPD. The aim of the study was to characterize the phenotype of concurrent chronic bronchitis and frequent exacerbation in severe COPD. Methods: Information on patient characteristics, comorbidity, and exacerbations from the previous year (total number and number requiring hospitalization) was collected from 373 patients with stage III and IV COPD attending 27 secondary care respiratory units in Sweden. Logistic regression used chronic bronchitis and frequent exacerbations (. 2 exacerbations or. 1 hospitalized exacerbations in the previous year) as response variables. Stratification and interaction analyses examined effect modification by sex. Results: Chronic bronchitis was associated with current smoking (adjusted odds ratio [OR] [95% CI], 2.75 [1.54-4.91]; P=0.001), frequent exacerbations (OR [95% CI], 1.93 [1.24-3.01]; P=0.004), and musculoskeletal symptoms (OR [95% CI], 1.74 [1.05-2.86]; P=0.031), while frequent exacerbations were associated with lung function (forced expiratory volume in 1 second as a percentage of predicted value [FEV1% pred]) (OR [95% CI] 0.96 [0.94-0.98]; P=0.001) and chronic bronchitis (OR [95% CI] 1.73 [1.11-2.68]; P=0.015). The phenotype with both chronic bronchitis and frequent exacerbations was associated with FEV1% pred (OR [95% CI] 0.95 [0.92-0.98]; P=0.002) and musculoskeletal symptoms (OR [95% CI] 2.55 [1.31-4.99]; P=0.006). The association of smoking with the phenotype of chronic bronchitis and exacerbations was stronger in women than in men (interaction, P=0.040). Conclusion: Musculoskeletal symptoms and low lung function are associated with the phenotype of combined chronic bronchitis and frequent exacerbations in severe COPD. In women, current smoking is of specific importance for this phenotype. This should be considered in clinical COPD care

The phenotype of concurrent chronic bronchitis and frequent exacerbations in patients with severe COPD attending Swedish secondary care units

Background: Chronic bronchitis and previous exacerbations are both well-known risk factors for new exacerbations, impaired health-related quality of life, and increased mortality in COPD. The aim of the study was to characterize the phenotype of concurrent chronic bronchitis and frequent exacerbation in severe COPD. Methods: Information on patient characteristics, comorbidity, and exacerbations from the previous year (total number and number requiring hospitalization) was collected from 373 patients with stage III and IV COPD attending 27 secondary care respiratory units in Sweden. Logistic regression used chronic bronchitis and frequent exacerbations (. 2 exacerbations or. 1 hospitalized exacerbations in the previous year) as response variables. Stratification and interaction analyses examined effect modification by sex. Results: Chronic bronchitis was associated with current smoking (adjusted odds ratio [OR] [95% CI], 2.75 [1.54-4.91]; P=0.001), frequent exacerbations (OR [95% CI], 1.93 [1.24-3.01]; P=0.004), and musculoskeletal symptoms (OR [95% CI], 1.74 [1.05-2.86]; P=0.031), while frequent exacerbations were associated with lung function (forced expiratory volume in 1 second as a percentage of predicted value [FEV1% pred]) (OR [95% CI] 0.96 [0.94-0.98]; P=0.001) and chronic bronchitis (OR [95% CI] 1.73 [1.11-2.68]; P=0.015). The phenotype with both chronic bronchitis and frequent exacerbations was associated with FEV1% pred (OR [95% CI] 0.95 [0.92-0.98]; P=0.002) and musculoskeletal symptoms (OR [95% CI] 2.55 [1.31-4.99]; P=0.006). The association of smoking with the phenotype of chronic bronchitis and exacerbations was stronger in women than in men (interaction, P=0.040). Conclusion: Musculoskeletal symptoms and low lung function are associated with the phenotype of combined chronic bronchitis and frequent exacerbations in severe COPD. In women, current smoking is of specific importance for this phenotype. This should be considered in clinical COPD care