1,392 research outputs found

    Using Social Networking for Educational and Cultural Adaptation: An Exploratory Study

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    This study investigates how an innovative technology, social networking, can be used in the process of building and maintaining social capital and exchanging knowledge in an educational setting. We employ a qualitative methodology, autoethnography, to examine how social networking can help students learn from other classmates and professors, exchange knowledge, and adjust both to a new program of study and to living in the United States. Using the theoretical foundation of social capital (Jacobs, 1960) and a social support framework created by Drentea and Moren-Cross (2005), autobiographical narratives are classified as instrumental support, emotional support, and community building. Our findings provide evidence that social networking sites can enhance social capital through these mechanisms in a doctoral education context, and our research serves as an important first step in addressing a gap in educational and cultural adaptation studies using social networking tools

    No Differences in Strength Improvements Following Low- or High-Volume Resistance Training

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    Resistance training is a widely used modality for improving muscular strength and reducing risks of injury, which is vital to counteracting physical declines associated with aging and poor health. Despite this, the minimal effective training dose for improving muscular strength has yet to be fully elucidated. PURPOSE: The purpose of this study was to examine the role of training volume (number of sets per session) on muscular strength changes following 8 weeks of progressive resistance training. METHODS: Fourteen and 12 trained males (Mean±SD; Age: 23±3y) and females (Age: 20±1y) participated in 8 weeks of supervised 3x/week progressive resistance training. Experimental sessions consisted of 3-5 repetition maximum testing both pre- and post-intervention, in accordance with the protocol outlined by the NSCA, in the following exercises: leg press (LP), bench press (BP), horizontal row (ROW), barbell Romanian deadlift (RDL), dumbbell overhead press (OHP), and lat pulldown (LAT). Following baseline strength testing, each participant was randomly allocated to either a low volume (LV; n=12 (5F)) or high volume (HV; n=14 (7F)) training group, completing 2 or 4 sets per exercise per training visit, respectively. Across all 8 weeks, participants completed each lift twice weekly, and loads were adjusted based on exercise performance using the autoregulated progressive resistance exercise protocol. Each group completed the same repetitions in their first sets, but completed the last set of every exercise until volitional failure. Percent change for each exercise was calculated as the difference between baseline strength (kgs) and post-training strength (kgs), expressed as a percentage of baseline strength. To examine the effect of group and exercise on the change in strength, a 2 (Group) × 6 (Exercise) analysis of covariance (ANCOVA) was performed, covarying for pre-test strength. In the event of a significant F test, the Bonferroni-corrected dependent-samples t-test was used. Values are presented as estimated marginal means ± standard error. RESULTS: There was no significant Group × Exercise interaction effect on percent strength change (p=0.754), nor a main effect of Group (p=0.397). However, there was a significant effect of Exercise (p\u3c0.001). Post-hoc analyses indicated, when collapsing across training groups, improvements in strength were greater in LP when compared to BP (40.6±6.8%; p\u3c0.001), RDL (26.9±6.1%; p\u3c0.001), OHP (37.4±7.9%; p\u3c0.001), and LAT (22.7±6.8%; p=0.015). Additionally, greater strength improvements were seen in ROW when compared to BP (29.7±4.5%, p\u3c0.001), RDL (16.0±4.6%, p\u3c0.001), and OHP (26.5±4.8%, p\u3c0.001). Finally, LAT experienced greater strength increases than both BP (17.8±4.5%, p\u3c0.01) and OHP (14.6±4.7%, p=0.036). There were no additional significant differences between exercises (p=0.054-0.999). CONCLUSION: Our findings suggest that a resistance training volume of as few as 2 sets per exercise twice weekly is adequate to induce muscular strength adaptations in previously trained young adults. Further examination is needed to determine if upper and lower body exercises require differing volumes to elicit similar adaptations

    The Landscape of Galaxies Harboring Changing-Look Active Galactic Nuclei in the Local Universe

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    We study the properties of the host galaxies of Changing-Look Active Galactic Nuclei (CL AGNs) with the aim of understanding the conditions responsible for triggering CL activity. We find that CL AGN hosts primarily reside in the so-called green valley that is located between spiral-like star-forming galaxies and dead ellipticals, implying that CL AGNs are activated during distinct periods of quenching and galaxy transformation processes. CL AGN hosts have low galaxy asymmetry indicators, suggesting that secular evolutionary processes (the influence of bars and spirals, and possibly minor mergers) might be the primary mechanism for transporting gas to the vicinity of the supermassive black hole (SMBH) rather than major mergers. Similar to tidal disruption events (TDEs) and highly variable AGNs, we find that CL AGN hosts are associated with SMBHs residing in high density pseudo-bulges and appear to overlap most significantly with the population of low-ionization nuclear emission-line region (LINER) galaxies. As such, CL AGN are likely fueled by strong episodic bursts of accretion activity, which appear to take place preferentially as the amount of material accessible for star formation and accretion dwindles. We also identify that CL AGN hosts are characterized by either large S\'ersic indices or high bulge fractions, which suggests a simple metric for identifying candidates for spectroscopic follow-up observations in forthcoming synoptic surveys.Comment: 17 pages, 9 figures. Accepted to ApJ Letters. Revised version includes an expanded discussion on asymmetry measurements and galaxy disturbance

    Sphingosine 1-phosphate, a potential target in neovascular retinal disease

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    Neovascular ocular diseases (such as age-related macular degeneration, diabetic retinopathy and retinal vein occlusion) are characterised by common pathological processes that contribute to disease progression. These include angiogenesis, oedema, inflammation, cell death and fibrosis. Currently available therapies target the effects of vascular endothelial growth factor (VEGF), the main mediator of pathological angiogenesis. Unfortunately, VEGF blockers are expensive biological therapeutics that necessitate frequent intravitreal administration and are associated with multiple adverse effects. Thus, alternative treatment options associated with fewer side effects are required for disease management. This review introduces sphingosine 1-phosphate (S1P) as a potential pharmacological target for the treatment of neovascular ocular pathologies. S1P is a sphingolipid mediator that controls cellular growth, differentiation, survival and death. S1P actions are mediated by five G protein-coupled receptors (S1P1-5 receptors) which are abundantly expressed in all retinal and subretinal structures. The action of S1P on S1P1 receptors can reduce angiogenesis, increase endothelium integrity, reduce photoreceptor apoptosis and protect the retina against neurodegeneration. Conversely, S1P2 receptor signalling can increase neovascularisation, disrupt endothelial junctions, stimulate VEGF release, and induce retinal cell apoptosis and degeneration of neural retina. The aim of this review is to thoroughly discuss the role of S1P and its different receptor subtypes in angiogenesis, inflammation, apoptosis and fibrosis in order to determine which of these S1P-mediated processes may be targeted therapeutically

    The effect of a single dose of beetroot juice on speed, strength, and power in healthy recreationally active females.

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    Nitrate-rich beetroot juice (BR) improves muscle contraction which is relevant for intense intermittent-type sports. However, few studies have examined the effect of BR ingestion on performance using sport-specific exercise protocols. Moreover, there is a scarcity of research that include female participants which limits real world application given that females potentially have different responses to BR ingestion. The purpose of the present study was to examine the effect of BR supplementation on speed, acceleration, strength and power before and after fatigue in females. In a double-blind, randomized crossover design, 15 recreationally active females consumed BR and nitrate-depleted placebo juice (PL) ~2.5 hours prior to exercise testing. Measurements included 20 m sprint and acceleration using timing gates, strength using isokinetic handgrip dynamometry, and upper and lower body power using the medicine ball power throw and countermovement jump (CMJ) before and after a fatiguing running protocol. Data from a subset of participants (n=15) were analyzed and revealed no significant difference between PL and BR for 20 m speed and 10 m acceleration (P\u3e0.05), isokinetic handgrip dynamometry (PL: PRE: 76±10 vs POST: 76±13; BR: PRE: 78±12 vs POST: 78±12 lb; P\u3e0.05), medicine ball power throw (PL: PRE: 4.45±0.48 vs POST: 4.35±0.48; BR: PRE: 4.41±0.38 vs POST: 4.49±0.47 m; P\u3e0.05) or CMJ (PL: PRE: 1.72±0.27 vs POST: 1.7±0.26; BR: PRE: 1.77±0.25 vs POST: 1.73±0.28 m; P\u3e0.05). These results indicate that there are no effects of BR supplementation on exercise performance in female athletes; however, this study is currently underpowered, and research is still in progress

    Longitudinal Body Composition Changes in NCAA Division I College Football Players

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    Many athletes seek to optimize body composition to fit the physical demands of their sport. American football requires a unique combination of size, speed, and power. The purpose of the current study was to evaluate longitudinal changes in body composition in Division I collegiate football players. For 57 players (Mean ± SD; Age=19.5 ± 0.9 yrs; Height=186.9 ± 5.7 cm; Weight=107.7 ± 19.1 kg), body composition was assessed via dual-energy x-ray absorptiometry in the off-season (March-Pre), end of off-season (May), mid-July (Pre-Season), and the following March (March-Post). Outcome variables included weight, body fat percentage (BF%), fat mass (FM), lean mass (LM), android (AND) and gynoid (GYN) fat, bone mineral content (BMC), and bone density (BMD). For a subset of athletes (n=13 out of 57), changes over a 4-year playing career were evaluated with measurements taken every March. Throughout a single year, favorable changes were observed for BF% (Δ=−1.3 ± 2.5%), LM (Δ=2.8 ± 2.8 kg), GYN (Δ=−1.5 ± 3.0%), BMC (Δ=0.06 ± 0.14 kg), and BMD (Δ=0.015 ± 0.027g·cm−2; all p<0.05). Across four years, weight increased significantly (Δ=6.6 ± 4.1kg), and favorable changes were observed for LM (Δ=4.3 ± 3.0 kg), BMC (Δ=0.18 ± 0.17 kg), and BMD (Δ=0.033 ± 0.039 g·cm−2; all p<0.05). Similar patterns in body composition changes were observed for linemen and non-linemen. Results indicate that well-trained collegiate football players at high levels of competition can achieve favorable changes in body composition, even late in the career, which may confer benefits for performance and injury prevention

    The effects of nitrate-rich beetroot juice supplementation on nonverbal executive function in healthy recreationally active females

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    Nitrate-rich beetroot juice (BR) supplementation has been reported to preserve executive function (i.e. decision making and reaction time) before and after a simulated soccer match in recreationally active males, which may be due to enhanced cerebral blood flow. However, the literature examining the physiological response following BR ingestion in females is scarce, which hampers the extrapolation of results since physiological sex-differences may exist. Therefore, the purpose of this study was to assess if BR ingestion influenced executive function in an unfatigued and fatigued state in healthy recreationally active females. In a double-blind, randomized crossover design, 20 females consumed 140 mL of concentrated BR or nitrate-depleted placebo juice (PL) approximately 2.5 hours prior to each experimental visit. The Delis-Kaplan Executive Function (D-KEF) test, used for assessing higher-level cognitive function, was administered before and after completing a high-intensity intermittent running protocol. The D-KEF test involved 3 x 60-s conditions evaluating various cognitive tasks. A two-way repeated measures analysis of variance was conducted (n=15) and revealed no significant differences in executive function between PL (PRE: 15.27 ± 32.71 vs. POST: 16.93 ± 1.44) and BR (PRE: 15.80 ± 2.65 vs. POST: 16.60 ± 1.88). These preliminary data suggest that acute BR ingestion does not have an influence on processing and creative thinking of nonverbal executive function in an unfatigued or fatigued state in healthy recreationally active females, although importantly, the study is still in progress

    In vitro dissolution models for the prediction of in vivo performance of an oral mesoporous silica formulation

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    Drug release from mesoporous silica systems has been widely investigated in vitro using USP Type II (paddle) dissolution apparatus. However, it is not clear if the observed enhanced in vitro dissolution can forecast drug bioavailability in vivo. In this study, the ability of different in vitro dissolution models to predict in vivo oral bioavailability in a pig model was examined. The fenofibrate-loaded mesoporous silica formulation was compared directly to a commercial reference product, Lipantil Supra®. Three in vitro dissolution methods were considered; USP Type II (paddle) apparatus, USP Type IV (flow-through cell) apparatus and a USP IV Transfer model (incorporating a SGF to FaSSIF-V2 media transfer). In silico modelling, using a physiologically based pharmacokinetic modelling and simulation software package (Gastroplus™), to generate in vitro/in vivo relationships was also investigated. The study demonstrates that the in vitro dissolution performance of a mesoporous silica formulation varies depending on the dissolution apparatus utilised and experimental design. The findings show that the USP IV transfer model was the best predictor of in vivo bioavailability. The USP Type II (paddle) apparatus was not effective at forecasting in vivo behaviour. This observation is likely due to hydrodynamic differences between the two apparatus and the ability of the transfer model to better simulate gastrointestinal transit. The transfer model is advantageous in forecasting in vivo behaviour for formulations which promote drug supersaturation and as a result are prone to precipitation to a more energetically favourable, less soluble form. The USP IV transfer model could prove useful in future mesoporous silica formulation development. In silico modelling has the potential to assist in this process. However, further investigation is required to overcome the limitations of the model for solubility enhancing formulations

    Estimating and exploring the proportions of inter- and intrastate cattle shipments in the United States

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    Mathematical models are key tools for the development of surveillance, preparedness and response plans for the potential events of emerging and introduced foreign animal diseases. Creating these types of plans requires data; when data are incomplete, mathematical models can help fill in missing information, provided they are informed by the data that are available. In the United States, the most complete national-scale data available on cattle shipments are based on Interstate Certificates of Veterinary Inspection, which track the shipment of cattle between states; data on intrastate cattle shipments are lacking. Here we develop four new datasets on intrastate cattle shipments in the U.S., including an expert elicitation survey covering 19 states and territories and three state-level brand inspection data sets. The expert elicitation survey provides estimates on the proportion of shipments that travel interstate over multiple regions of the U.S. These survey data also identify differences in shipment patterns between regions, cattle commodity types, and sectors of the cattle industry. These survey data cover more states than any other source of intrastate data; however, one limitation of these data is the small number of participating experts in many of the states, only seven of the 19 responding states and territories had a group size of three or larger. The brand data sets include origin and destination information for both intra- and interstate shipments. These data, therefore, also provide detailed information on the proportion of interstate shipments in three Western states, including the temporal and geographic variation in shipments. Because the survey and brand data overlap in the Western U.S., they can be compared. We find that in the Western U.S. the expert estimates of the overall proportion of cattle shipments matched the brand data well. However, the experts estimated that there would be larger differences in beef and dairy shipments than the brand data show. This suggests the cattle industries in the West may be sending similar proportions of commodity specific cattle shipments over state lines. We additionally used the expert survey data to explore how differences in the proportion of interstate shipments can change predictions about cattle shipment patterns using the example of model-guided suggestions for targeted surveillance in Texas. Together these four data sets are the most extensive and geographically comprehensive information to date on intrastate cattle shipments. Additionally, our analyses on predicted shipment patterns suggest that assumptions about intrastate shipments could have consequences for targeted surveillance
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