266 research outputs found
Do terraces and coconut mats affect seeds and submerged aquatic vegetation at Sabine National Wildlife Refuge?
Terraces are a widely used wetland restoration tools in coastal Louisiana, yet the benefits of terraces are poorly documented. Like terraces, coconut mats also may increase abundance of submerged aquatic vegetation (SAV), but their benefits are undocumented. I compared SAV and seed abundance in a marsh pond among three treatments: terrace, coconut mat, and marsh. I evaluated terraces constructed in 1999 and coconut mats installed in 2001 in portions of unit 7 of Sabine National Wildlife Refuge that converted from emergent marsh to open water between 1956 and 1978. I randomly selected 3 terrace, marsh, and coconut mat stations. I evaluated transects 0 meters, 5 meters, and 50 meters (here after open water) from emergent vegetation at each station. Submerged aquatic vegetation was evaluated on the terrace and marsh by harvesting SAV from 10-cm diameter cores, harvesting SAV from 1-m2 plots, and raking: only 1-m2 plot sampling was conducted on coconut mat treatments. I evaluated seed abundance on terrace and marsh transects with 10-cm diameter cores, which could not be used on the coconut mats. Submerged aquatic vegetation biomass differed between treatments and sampling dates. Biomass of SAV, as estimated by the cores, was greater on the marsh transects than the terrace transects. The SAV biomass, as estimated by 1-m2 plots, was greatest during September 2002. Biomass of SAV, as estimated by 1-m2 plots, was greater on coconut mats than terrace or marsh transects. Raking indicated that in September 2002, the percent occurrence of SAV was greater on the marsh transects than on the terrace transects. Seed biomass was greater adjacent to marsh than to terraces, which was similar to that in open water. Seeds of sawgrass (Cladium jamaicense Crantz) accounted for 87% of the seed biomass but did not germinate in a greenhouse. My results indicated that terraces failed to increase SAV abundance above levels found in open water as was predicted. I concluded that restoration planners should no longer assume that terraces increase SAV abundance. Coconut mats increased SAV abundance. Additional studies on a variety of areas and configurations are needed to determine if my observations are typical
Influence of Heating and Biological Sex on Vascular Dysfunction Associated with Long-Duration Sitting and Standing
Purpose: The purpose of these studies was to determine if arterial angulations (through sitting or standing), shear stress (through local heating), or a combination of these factors affected vascular function. Moreover, this studied estimated the magnitude of the effect that biological sex has on these vascular responses. Methods: Twenty-six healthy, young (18-40 years old) males (n=13) and females (n=13) completed two experimental trials (2-h sitting and 2-h standing). In a randomized fashion, one leg was passively heated in order to increase shear rate. Following a 48-h washout, participants returned to the laboratory to complete the other trial. Flow-mediated dilation (FMD) at the superficial femoral artery (SFA), and central and peripheral pulse-wave velocity (PWV) were measured using vascular ultrasound. Endothelin-1 (ET-1) was analyzed using an enzyme-linked immunoassay (ELISA). Results: There was a non-significant decrease in FMD (1.45%; p = .06) during sitting and the decline in FMD was not different between biological sexes (p \u3e .05). Further, standing resulted in a significant increase in peripheral PWV (50 cm/s; p \u3c .05) but there was no change during sitting (p \u3e .05). Overall, passive heating (1.42%; p \u3c .05) and standing (1.42%; p \u3c .05) both independently improved FMD in comparison to sitting. However, neither intervention attenuated the increases in peripheral PWV that occurred during standing (p \u3e .05). ET-1 did not increase over the course of either trial and was not different between sexes (p \u3e .05). Antegrade shear rate increased (p \u3c .001) and retrograde stress decreased (p \u3c .001) when passively heated. Further, there was vasoconstriction during standing with SFA diameter decreasing compared to sitting (0.28 mm; p \u3c .001). Conclusions: Both interventions, passive heating and standing, appear to be equally effective at improving FMD. Further, we demonstrate that there is no significant impact of biological sex on sitting induced vascular dysfunction and the interventions intended to prevent this dysfunction. However, standing increased peripheral PWV and passive heating did not attenuate this response
Olfaction and anxiety are differently associated in men and women in cognitive physiological and pathological aging
Background: Olfaction impairment in aging is associated with increased anxiety. We
explored this association in cognitively healthy controls (HCs), Mild Cognitive Impairment (MCI) and
Parkinson’s disease (PD) patients. Both olfaction and anxiety have sex differences, therefore we also
investigated these variances. Objectives: Investigate the association of olfaction with anxiety in three
distinct clinical categories of aging, exploring the potential role of sex. Methods: 117 subjects (29 HCs,
43 MCI, and 45 PD patients) were assessed for olfaction and anxiety. We used regression models
to determine whether B-SIT predicted anxiety and whether sex impacted that relationship. Results:
Lower olfaction was related to greater anxiety traits in all groups (HCs: p = 0.015; MCI: p = 0.001
and PD: p = 0.038), significantly differed by sex. In fact, in HCs, for every unit increase in B-SIT,
anxiety traits decreased by 7.63 in men (p = 0.009) and 1.5 in women (p = 0.225). In MCI patients for
every unit increase in B-SIT, anxiety traits decreased by 1.19 in men (p = 0.048) and 3.03 in women
(p = 0.0036). Finally, in PD patients for every unit increase in B-SIT, anxiety traits decreased by 1.73 in
men (p = 0.004) and 0.41 in women (p = 0.3632). Discussion: Olfaction and anxiety are correlated in
all three distinct diagnostic categories, but differently in men and women
Proposal of a Selection Protocol for Replication of Studies in Sports and Exercise Science
To improve the rigor of science, experimental evidence for scientific claims ideally needs to be replicated repeatedly with comparable analyses and new data to increase the collective confidence in the veracity of those claims. Large replication projects in psychology and cancer biology have evaluated the replicability of their fields but no collaborative effort has been undertaken in sports and exercise science. We propose to undertake such an effort here. As this is the first large replication project in this field, there is no agreed-upon protocol for selecting studies to replicate. Criticism of previous selection protocols include claims they were non-randomised and non-representative. Any selection protocol in sports and exercise science must be representative to provide an accurate estimate of replicability of the field. Our aim is to produce a protocol for selecting studies to replicate for inclusion in a large replication project in sports and exercise science
Distances to Populous Clusters in the LMC via the K-Band Luminosity of the Red Clump
We present results from a study of the distances and distribution of a sample
of intermediate-age clusters in the Large Magellanic Cloud. Using deep
near-infrared photometry obtained with ISPI on the CTIO 4m, we have measured
the apparent K-band magnitude of the core helium burning red clump stars in 17
LMC clusters. We combine cluster ages and metallicities with the work of
Grocholski & Sarajedini to predict each cluster's absolute K-band red clump
magnitude, and thereby calculate absolute cluster distances. An analysis of
these data shows that the cluster distribution is in good agreement with the
thick, inclined disk geometry of the LMC, as defined by its field stars. We
also find that the old globular clusters follow the same distribution,
suggesting that the LMC's disk formed at about the same time as the globular
clusters, ~ 13 Gyr ago. Finally, we have used our cluster distances in
conjunction with the disk geometry to calculate the distance to the LMC center,
for which we find (m-M)o = 18.40 +/- 0.04_{ran} +/- 0.08_{sys}, or Do = 47.9
+/- 0.9 +/- 1.8 kpc.Comment: 31 pages including 5 figures and 7 tables. Accepted for publication
in the August 2007 issue of A
Confidence in eating disorder knowledge does not predict actual knowledge in collegiate female athletes
Background Eating disorders are serious psychological disorders with long term health impacts. Athletic populations, tend to have higher incidences of eating disorders compared to the general population. Yet there is little known about athletes’ eating disorder knowledge and how it relates to their confidence in their knowledge. Therefore, the purpose of our study was to evaluate collegiate female athletes’ eating disorder (ED) knowledge and confidence in their knowledge. 51 participants were recruited from a National Association of Intercollegiate Athletics (NAIA) university in the mid-west and asked to complete a 30-question exam assessing one’s knowledge of five different categories related to eating disorders. Confidence in the correctness of answers was assessed with a 5-point Likert-scale (1 = very unconfident, 5 = very confident). A one-way ANOVA was used to determine differences between scores on different categories and overall scores. A simple regression analysis was used to determine if confidence or age was predictive in knowledge scores. Results The average score of participants was 69.1%, SD = 10.8% with an average confidence of 3.69/5, SD = 0.33. Athletes scored lowest with regards to Identifying Signs and Symptoms of EDs compared to other sub-scores (p < 0.05). There was no relationship between knowledge and confidence scores. Discussion There is limited ED knowledge among collegiate female athletes. This may be problematic as many athletes appear confident in the correctness of their answers despite these low scores. Coaches should be aware of this lack of knowledge and work with clinical practitioners, such as dieticians, team physicians and athletic trainers to educate and monitor their athletes on eating disorders, specifically signs and symptoms
The Parkinson\u27s Disease Protein α-Synuclein Disrupts Cellular Rab Homeostasis
α-Synuclein (α-syn), a protein of unknown function, is the most abundant protein in Lewy bodies, the histological hallmark of Parkinson\u27s disease (PD). In yeast α-syn inhibits endoplasmic reticulum (ER)-to-Golgi (ER→Golgi) vesicle trafficking, which is rescued by overexpression of a Rab GTPase that regulates ER→Golgi trafficking. The homologous Rab1 rescues α-syn toxicity in dopaminergic neuronal models of PD. Here we investigate this conserved feature of α-syn pathobiology. In a cell-free system with purified transport factors α-syn inhibited ER→Golgi trafficking in an α-syn dose-dependent manner. Vesicles budded efficiently from the ER, but their docking or fusion to Golgi membranes was inhibited. Thus, the in vivo trafficking problem is due to a direct effect of α-syn on the transport machinery. By ultrastructural analysis the earliest in vivo defect was an accumulation of morphologically undocked vesicles, starting near the plasma membrane and growing into massive intracellular vesicular clusters in a dose-dependent manner. By immunofluorescence/immunoelectron microscopy, these clusters were associated both with α-syn and with diverse vesicle markers, suggesting that α-syn can impair multiple trafficking steps. Other Rabs did not ameliorate α-syn toxicity in yeast, but RAB3A, which is highly expressed in neurons and localized to presynaptic termini, and RAB8A, which is localized to post-Golgi vesicles, suppressed toxicity in neuronal models of PD. Thus, α-syn causes general defects in vesicle trafficking, to which dopaminergic neurons are especially sensitive
Exclusive processes in electron - ion collisions
The exclusive processes in electron-ion () interactions are an important
tool to investigate the QCD dynamics at high energies as they are in general
driven by the gluon content of the target, which is strongly subject to parton
saturation effects. In this paper we compute the cross sections for the
exclusive vector meson production as well as the deeply virtual Compton
scattering (DVCS) relying on the color dipole approach and considering the
numerical solution of the Balitsky-Kovchegov equation including running
coupling corrections (rcBK). The production cross sections obtained with the
rcBK solution and bCGC parametrization are very similar, the former being
slightly larger.Comment: 6 pages, 4 figure
A longitudinal study examining the effects of a season of American football on lipids and lipoproteins
Background
Dyslipidemia is one factor cited for increased risk of cardiovascular disease (CVD) in American football players. However, American football players undergo physical conditioning which is known to influence lipids. This study examined if the physical activity of an American football season is associated with changes in lipids and if a relationship exists between lipids and body composition.
Methods
Fourteen division I freshmen American football players had blood drawn prior to summer training (T1), end of competition (T2), and end of spring training (T3). Samples were analyzed for total cholesterol (TCHL), HDL-C, LDL-C, and triglycerides (TG). Body composition was assessed via dual-x-ray absorptiometry. National Cholesterol Education Program (NCEP) lipid categorization was used to characterize participants. Pearson correlations were computed to determine relationships.
Results
Body mass increased T2 (p = 0.008) as a result of increase in fat mass (p = 0.005) and remained high despite a decrease T3. Lean mass did not differ significantly at any time. No significant time effects were observed for lipids measured. The number of participants presenting with risk factors attributed to dyslipidemia varied. By T3, no participant was categorized as “low” for HDL-C. TCHL was moderately correlated (r = 0.60) with fat mass at T1; whereas a moderate correlation (r = −0.57) was observed between BMI and HDL-C at T2. TG was strongly correlated with fat mass at each time point (T1, r = 0.83; T2, r = 0.94; T3, r = 0.70).
Conclusion
The physical activity associated with a season of football results in little change in blood lipids and CVD risk. Further, TG are strongly related to fat mass. Future research should focus on examining the cause of dyslipidemia in American football players.The open access fee for this work was funded through the Texas A&M University Open Access to Knowledge (OAK) Fund
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