An Ultraviolet-to-Radio Broadband Spectral Atlas of Nearby Galaxies

The ultraviolet-to-radio continuum spectral energy distributions are presented for all 75 galaxies in the Spitzer Infrared Nearby Galaxies Survey (SINGS). A principal component analysis of the sample shows that most of the sample's spectral variations stem from two underlying components, one representative of a galaxy with a low infrared-to-ultraviolet ratio and one representative of a galaxy with a high infrared-to-ultraviolet ratio. The influence of several parameters on the infrared-to-ultraviolet ratio is studied (e.g., optical morphology, disk inclination, far-infrared color, ultraviolet spectral slope, and star formation history). Consistent with our understanding of normal star-forming galaxies, the SINGS sample of galaxies in comparison to more actively star-forming galaxies exhibits a larger dispersion in the infrared-to-ultraviolet versus ultraviolet spectral slope correlation. Early type galaxies, exhibiting low star formation rates and high optical surface brightnesses, have the most discrepant infrared-to-ultraviolet correlation. These results suggest that the star formation history may be the dominant regulator of the broadband spectral variations between galaxies. Finally, a new discovery shows that the 24 micron morphology can be a useful tool for parametrizing the global dust temperature and ultraviolet extinction in nearby galaxies. The dust emission in dwarf/irregular galaxies is clumpy and warm accompanied by low ultraviolet extinction, while in spiral galaxies there is typically a much larger diffuse component of cooler dust and average ultraviolet extinction. For galaxies with nuclear 24 micron emission, the dust temperature and ultraviolet extinction are relatively high compared to disk galaxies.Comment: Accepted for publication in the Astrophysical Journal; Fixed radio flux density units (mJy

Academic Performance and Behavioral Patterns

Identifying the factors that influence academic performance is an essential part of educational research. Previous studies have documented the importance of personality traits, class attendance, and social network structure. Because most of these analyses were based on a single behavioral aspect and/or small sample sizes, there is currently no quantification of the interplay of these factors. Here, we study the academic performance among a cohort of 538 undergraduate students forming a single, densely connected social network. Our work is based on data collected using smartphones, which the students used as their primary phones for two years. The availability of multi-channel data from a single population allows us to directly compare the explanatory power of individual and social characteristics. We find that the most informative indicators of performance are based on social ties and that network indicators result in better model performance than individual characteristics (including both personality and class attendance). We confirm earlier findings that class attendance is the most important predictor among individual characteristics. Finally, our results suggest the presence of strong homophily and/or peer effects among university students

Cerebral cortical thickness in chronic pain due to knee osteoarthritis: the effect of pain duration and pain densitization

Objective This study investigates associations between cortical thickness and pain duration, and central sensitization as markers of pain progression in painful knee osteoarthritis. Methods Whole brain cortical thickness and pressure pain thresholds were assessed in 70 participants; 40 patients with chronic painful knee osteoarthritis (age = 66.1± 8.5 years, 21 females, mean duration of pain = 8.5 years), and 30 healthy controls (age = 62.7± 7.4, 17 females). Results Cortical thickness negatively correlated with pain duration mainly in fronto-temporal areas outside of classical pain processing areas (p<0.05, age-controlled, FDR corrected). Pain sensitivity was unrelated to cortical thickness. Patients showed lower cortical thickness in the right anterior insula (p<0.001, uncorrected) with no changes surviving multiple test correction. Conclusion With increasing number of years of suffering from chronic arthritis pain we found increasing cortical thinning in extended cerebral cortical regions beyond recognised pain-processing areas. While the mechanisms of cortical thinning remain to be elucidated, we show that pain progression indexed by central sensitization does not play a major role

Mechanism of exaggerated natriuresis in hypertensive man: impaired sodium transport in the loop of Henle.

To evaluate the effects of saline loading on distal sodium reabsorption in hypertensive man, studies were performed during both water deprivation and water diuresis in eight hypertensive subjects, and the results were compared to data obtained from similar studies in normal subjects. All hypertensive patients exhibited an enhanced excretion of filtered sodium (C(Na)/C(In)) at any level of distal delivery of sodium compared to normal controls. Free water reabsorption (T(c) (H2O)) during hypertonic saline loading was quantitatively abnormal in the hypertensives at high levels of osmolar clearance (C(Osm)), and also the curve of T(c) (H2O) vs. C(Osm) leveled off above a C(Osm) of 18 ml/min per 1.73 m(2) in the hypertensive group in contrast to the normal controls in whom T(c) (H2O) showed no evidence of achieving an upper limit. Sodium depletion exaggerated the abnormality in T(c) (H2O) in hypertensives, and resulted in a positive free water clearance (C(H2O)) during hydropenia. During hypotonic saline loading in water diuresis, changes in free water clearance per 100 ml of glomerular filtrate (C(H2O)/C(In)) were less at any given increment in urine flow per 100 ml of glomerular filtrate (V/C(In)) in the hypertensives compared to normal controls (P \u3c 0.001). This abnormality in C(H2O)/C(In) in the hypertensives in conjunction with the defect in T(c) (H2O) observed during hydropenia indicates that sodium reabsorption in the loop of Henle was abnormal at any given rate of distal delivery of sodium in hypertension. Furthermore, these abnormalities in T(c) (H2O) and C(H2O) coincided temporally with the development of the exaggerated natriuresis. Although the distal defect in sodium transport, in large part, accounted for the augmented natriuresis in hypertension, evidence was present also for enhanced rejection of sodium in the proximal tubule during saline loading in the hypertensives. Additional studies utilizing acetazolamide which increases distal delivery of sodium without extracellular fluid volume expansion showed only minimal abnormalities in C(H2O) in the hypertensive group, indicating that the defect in sodium transport in the loop of Henle in hypertensives is mainly an abnormal response to extracellular fluid expansion rather than an intrinsic defect in the loop to handle increased tubular loads of sodium. It is possible that the abnormality in sodium reabsorption in the loop of Henle is due to the transmission of the abnormally elevated blood pressure of the hypertensives to the medullary vasa recta during saline loading