Gettysburg College

About: Gettysburg College is a education organization based out in Gettysburg, Pennsylvania, United States. It is known for research contribution in the topics: Population & Politics. The organization has 1223 authors who have published 2348 publications receiving 52162 citations. The organization is also known as: Pennsylvania College.

Osmotic and Nonosmotic Regulation of Arginine Vasopressin during Prolonged Endurance Exercise

Abstract: Context: Although the primary cause of exercise-associated hyponatremia (EAH) is relative overconsumption of fluids beyond the kidneys’ ability to excrete excess fluid, the mechanisms limiting maximum renal excretory ability during exercise remain to be elucidated. Objective: The objective of the study was to: 1) perform a comprehensive evaluation of the endocrine secretion of pituitary, natriuretic and adrenal steroid hormones, and cytokines immediately before and after running an ultramarathon; and 2) evaluate the relationship between osmotic and nonosmotic stimuli to arginine vasopressin (AVP) secretion within the overall context of assessing the hormonal regulation of fluid balance during prolonged endurance exercise. Design: This was an observational study. Setting: The study setting was a 56-km ultramarathon. Participants: Eighty-two runners participated in the study. Interventions: There were no interventions. Main Outcome Measures: Plasma sodium concentration [Na+] and plasma volume [(AVP)p] were measured. Results: Fluid homeostasis during exercise (356 ± 4 min) was maintained with ad libitum fluid intakes. [Na+] was maintained from before the race (139.3 ± 0.3 mmol/liter) to after the race (138.1 ± 0.4 mmol/liter) with a significant decrease in plasma volume (−8.5 ± 0.1%, P < 0.01). Increases in the plasma (AVP)p (3.9-fold), oxytocin (1.9-fold), brain natriuretic peptide (4.5-fold), and IL-6 (12.5-fold) were highly significant (P < 0.0001). Changes in brain natriuretic peptide, oxytocin, and corticosterone were associated with 47% of the variance noted in (AVP)p and 13% of the variance in plasma [Na+] in pathway analyses. Conclusions: (AVP)p was markedly elevated after the ultramarathon despite unchanged plasma [Na+]. Therefore, an inability to maximally suppress (AVP)P during exercise as a result of nonosmotic stimulation of AVP secretion may contribute to the pathogenesis of exercise-associated hyponatremia if voluntary fluid intake were to exceed fluid output.

Hybrid stars in a strong magnetic field

Abstract: We study the effects of high magnetic fields on the particle population and equation of state of hybrid stars using an extended hadronic and quark SU(3) non-linear realization of the sigma model. In this model the degrees of freedom change naturally from hadrons to quarks as the density and/or temperature increases. The effects of high magnetic fields and anomalous magnetic moment are visible in the macroscopic properties of the star, such as mass, adiabatic index, moment of inertia, and cooling curves. Moreover, at the same time that the magnetic fields become high enough to modify those properties, they make the star anisotropic.

Radial Velocity Survey of Members and Candidate Members of the TW Hydrae Association

Abstract: We report spectroscopic observations of stars belonging to the young nearby group known as the TW Hydrae association, as well as of a number of potential members of the association identified in kinematic and X-ray surveys. Multiple radial velocity measurements were obtained for each object, several of which turn out to be multiple systems. Orbital solutions are presented for three double-lined binaries, one singlelined binary, and a double-lined triple system, all with short periods. Effective temperatures and projected rotational velocities are presented for each visible object. None of the candidate members of the association in our sample are confirmed as a true member. The large fraction of close binaries among the candidate members has to do with their selection based on X-ray emission from ROSAT, which tends to favor the inclusion of tidally locked systems that are active but not necessarily young.

Effects of supplemental fish oil on resting metabolic rate, body composition, and salivary cortisol in healthy adults

Abstract: To determine the effects of supplemental fish oil (FO) on resting metabolic rate (RMR), body composition, and cortisol production in healthy adults. A total of 44 men and women (34 ± 13y, mean+SD) participated in the study. All testing was performed first thing in the morning following an overnight fast. Baseline measurements of RMR were measured using indirect calorimetry using a facemask, and body composition was measured using air displacement plethysmography. Saliva was collected via passive drool and analyzed for cortisol concentration using ELISA. Following baseline testing, subjects were randomly assigned in a double blind manner to one of two groups: 4 g/d of Safflower Oil (SO); or 4 g/d of FO supplying 1,600 mg/d eicosapentaenoic acid (EPA) and 800 mg/d docosahexaenoic acid (DHA). All tests were repeated following 6 wk of treatment. Pre to post differences were analyzed using a treatment X time repeated measures ANOVA, and correlations were analyzed using Pearson's r. Compared to the SO group, there was a significant increase in fat free mass following treatment with FO (FO = +0.5 ± 0.5 kg, SO = -0.1 ± 1.2 kg, p = 0.03), a significant reduction in fat mass (FO = -0.5 ± 1.3 kg, SO = +0.2 ± 1.2 kg, p = 0.04), and a tendency for a decrease in body fat percentage (FO = -0.4 ± 1.3% body fat, SO = +0. 3 ± 1.5% body fat, p = 0.08). No significant differences were observed for body mass (FO = 0.0 ± 0.9 kg, SO = +0.2 ± 0.8 kg), RMR (FO = +17 ± 260 kcal, SO = -62 ± 184 kcal) or respiratory exchange ratio (FO = -0.02 ± 0.09, SO = +0.02 ± 0.05). There was a tendency for salivary cortisol to decrease in the FO group (FO = -0.064 ± 0.142 μg/dL, SO = +0.016 ± 0.272 μg/dL, p = 0.11). There was a significant correlation in the FO group between change in cortisol and change in fat free mass (r = -0.504, p = 0.02) and fat mass (r = 0.661, p = 0.001). 6 wk of supplementation with FO significantly increased lean mass and decreased fat mass. These changes were significantly correlated with a reduction in salivary cortisol following FO treatment.

Gastrointestinal distress is common during a 161-km ultramarathon

Abstract: This study examined the incidence, severity, and timing of gastrointestinal (GI) symptoms in finishers and non-finishers of the 161-km Western States Endurance Run. A total of 272 runners (71.0% of starters) completed a post-race questionnaire that assessed the incidence and severity (none = 0, mild = 1, moderate = 2, severe = 3, very severe = 4) of 12 upper (reflux/heartburn, belching, stomach bloating, stomach cramps/pain, nausea, vomiting) and lower (intestinal cramps/pain, flatulence, side ache/stitch, urge to defecate, loose stool/diarrhoea, intestinal bleeding/bloody faeces) GI symptoms experienced during each of four race segments. GI symptoms were experienced by most runners (96.0%). Flatulence (65.9% frequency, mean value 1.0, s = 0.6 severity), belching (61.3% frequency, mean value 1.0, s = 0.6 severity), and nausea (60.3% frequency, mean value 1.0, s = 0.7 severity) were the most common symptoms. Among race finishers, 43.9% reported that GI symptoms affected their race performance, with...