359 research outputs found

    An Assessment of the Hydration Status of Recreational Endurance Athletes during Mountain Marathon Events.

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    Changes in hydration status have been shown to have deleterious effects on physiological functioning, physical performance, mental decision making, and subjective sensation of effort. This exploratory study assessed the hydration status of athletes taking part in mountain marathon events and the implications on performance, cognition and well-being markers. Twenty-nine male recreational athletes from the Original Mountain Marathon (OMM) and nineteen from the Longmynd Hike (LH) provided urine samples before, at mid-point (in the OMM) and after the events. Body mass; reaction time tests; and subjective ratings of well-being and effort were also collected/performed at these time points. Post-urine specific gravity (Usg) values [(OMM: 1.023 (range: 1.008 – 1.038) g/ml; LH: 1.024 (range: 1.014 – 1.035) g/ml] were significantly higher than pre-values [(OMM: 1.013 (range: 1.002 – 1.026) g/ml; LH: 1.013 (range: 1.002 – 1.026) g/ml] in both events (p 0.05). There was no association between hydration status and overall performance in the LH, whilst change in Usg from pre- to mid-event was positively associated with performance in the OMM (r = .561, p = 0.004). Whilst no associations were observed between hydration status and reaction time, rate of perceived exertion and subjective ratings of nausea showed positive associations with Usg. These findings suggest that although changes in hydration status of this level may not significantly affect performance, they can impact on participant sensations of effort and well-being

    Macronutrient Consumption Prior to, and During, Mountain Marathon Events

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    Participation in ultra-endurance events such as mountain marathons is increasing, yet analysis of the nutritional intake and requirements of this group of athletes have received relatively little attention. This field study examined athletes’ food intake prior to, and during a mountain marathon event to assess compliance with recommendations and to identify associations with performance. Nineteen male athletes competing in the Longmynd Hike (LH) completed a 7-day food diary in the week prior to the event and a weighed food inventory of all items consumed during the event. Despite reported intentions to increase carbohydrate (CHO) consumption in the week prior to the event, there was no significant change in consumption across the week. The mean daily CHO intake of 4.5 g/kg/d was below that recommended to effectively enhance glycogen stores. CHO and energy consumption prior to the event were positively associated with performance [energy (kJ/kg/d): r = .56, p = 0.03; CHO (g/kg/d): r = .54, p = 0.04]. Energy and CHO consumption during the event were also positively correlated with performance [energy (kJ/kg/h): r = .80, p < 0.001; CHO (g/kg/h): r = .75, p = 0.001)], despite most participants again failing to meet recommendations for intake. Further research is needed to determine reasons for non-compliance with nutritional guidelines and to investigate to what extent type and timing of macronutrient intake during such events impacts on performance

    The Inq13 POOC::A Participatory Experiment in Open, Collaborative Teaching and Learning.

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    This article offers a broad analysis of a POOC (“Participatory Open Online Course”) offered through the Graduate Center, CUNY in 2013. The large collaborative team of instructors, librarians, educational technologists, videographers, students, and project leaders reflects on the goals, aims, successes, and challenges of the experimental learning project. The graduate course, which sought to explore issues of participatory research, inequality and engaged uses of digital technology with and through the New York City neighborhood of East Harlem, set forth a unique model of connected learning that stands in contrast to the popular MOOC (Massive Open Online Course) model

    Regular breakfast consumption and type 2 diabetes risk markers in 9- to 10-year-old children in the child heart and health study in England (CHASE): a cross-sectional analysis.

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    BACKGROUND: Regular breakfast consumption may protect against type 2 diabetes risk in adults but little is known about its influence on type 2 diabetes risk markers in children. We investigated the associations between breakfast consumption (frequency and content) and risk markers for type 2 diabetes (particularly insulin resistance and glycaemia) and cardiovascular disease in children. METHODS AND FINDINGS: We conducted a cross-sectional study of 4,116 UK primary school children aged 9-10 years. Participants provided information on breakfast frequency, had measurements of body composition, and gave fasting blood samples for measurements of blood lipids, insulin, glucose, and glycated haemoglobin (HbA1c). A subgroup of 2,004 children also completed a 24-hour dietary recall. Among 4,116 children studied, 3,056 (74%) ate breakfast daily, 450 (11%) most days, 372 (9%) some days, and 238 (6%) not usually. Graded associations between breakfast frequency and risk markers were observed; children who reported not usually having breakfast had higher fasting insulin (percent difference 26.4%, 95% CI 16.6%-37.0%), insulin resistance (percent difference 26.7%, 95% CI 17.0%-37.2%), HbA1c (percent difference 1.2%, 95% CI 0.4%-2.0%), glucose (percent difference 1.0%, 95% CI 0.0%-2.0%), and urate (percent difference 6%, 95% CI 3%-10%) than those who reported having breakfast daily; these differences were little affected by adjustment for adiposity, socioeconomic status, and physical activity levels. When the higher levels of triglyceride, systolic blood pressure, and C-reactive protein for those who usually did not eat breakfast relative to those who ate breakfast daily were adjusted for adiposity, the differences were no longer significant. Children eating a high fibre cereal breakfast had lower insulin resistance than those eating other breakfast types (p for heterogeneity <0.01). Differences in nutrient intakes between breakfast frequency groups did not account for the differences in type 2 diabetes markers. CONCLUSIONS: Children who ate breakfast daily, particularly a high fibre cereal breakfast, had a more favourable type 2 diabetes risk profile. Trials are needed to quantify the protective effect of breakfast on emerging type 2 diabetes risk. Please see later in the article for the Editors' Summary

    Human Auditory Cortical Activation during Self-Vocalization

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    During speaking, auditory feedback is used to adjust vocalizations. The brain systems mediating this integrative ability have been investigated using a wide range of experimental strategies. In this report we examined how vocalization alters speech-sound processing within auditory cortex by directly recording evoked responses to vocalizations and playback stimuli using intracranial electrodes implanted in neurosurgery patients. Several new findings resulted from these high-resolution invasive recordings in human subjects. Suppressive effects of vocalization were found to occur only within circumscribed areas of auditory cortex. In addition, at a smaller number of sites, the opposite pattern was seen; cortical responses were enhanced during vocalization. This increase in activity was reflected in high gamma power changes, but was not evident in the averaged evoked potential waveforms. These new findings support forward models for vocal control in which efference copies of premotor cortex activity modulate sub-regions of auditory cortex

    Chimpanzees overcome the tragedy of the commons with dominance

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    Competition over common-pool resources (CPR) is a ubiquitous challenge for social animals. Many species face similar dilemmas, yet our understanding of the evolutionary trajectory of CPR social strategies remains unexplored. Here, we provide a first look at the social strategies of our closest living relatives, chimpanzees (Pan troglodytes), in two novel resource dilemma experiments. Dyads of chimpanzees were presented with renewable resource systems, collapsible at a quantity-dependent threshold. Dyads had to continuously resist overconsumption to maximize collective gains. In study 1, dyads of chimpanzees sustained a renewing juice source. Inequality of juice acquisition between partners predicted sustaining success, indicating that one individual dominated the task while the partner inhibited. Dyads in study 2 fed together on accumulating carrot pieces but could end the accumulation any time by grabbing an immediate selfish source of carrots. Dyads with low tolerance were more successful at collectively sustaining the resource than highly tolerant dyads. Further, the dominant individual was more likely to cause collapse in dyads with low tolerance than dyads with high tolerance. These results indicate that chimpanzees use a dominance-based monopolisation strategy moderated by social tolerance to overcome the tragedy of the commons

    Tumor Growth Decreases NK and B Cells as well as Common Lymphoid Progenitor

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    Background: It is well established that chronic tumor growth results in functional inactivation of T cells and NK cells. It is less clear, however, whether lymphopoeisis is affected by tumor growth. Principal Findings: In our efforts of analyzing the impact of tumor growth on NK cell development, we observed a major reduction of NK cell numbers in mice bearing multiple lineages of tumor cells. The decrease in NK cell numbers was not due to increased apoptosis or decreased proliferation in the NK compartment. In addition, transgenic expression of IL-15 also failed to rescue the defective production of NK cells. Our systematic characterization of lymphopoeisis in tumor-bearing mice indicated that the number of the common lymphoid progenitor was significantly reduced in tumor-bearing mice. The number of B cells also decreased substantially in tumor bearing mice. Conclusions and Significance: Our data reveal a novel mechanism for tumor evasion of host immunity and suggest a new interpretation for the altered myeloid and lymphoid ratio in tumor bearing hosts

    The auditory cortex of the bat Phyllostomus discolor: Localization and organization of basic response properties

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    <p>Abstract</p> <p>Background</p> <p>The mammalian auditory cortex can be subdivided into various fields characterized by neurophysiological and neuroarchitectural properties and by connections with different nuclei of the thalamus. Besides the primary auditory cortex, echolocating bats have cortical fields for the processing of temporal and spectral features of the echolocation pulses. This paper reports on location, neuroarchitecture and basic functional organization of the auditory cortex of the microchiropteran bat <it>Phyllostomus discolor </it>(family: Phyllostomidae).</p> <p>Results</p> <p>The auditory cortical area of <it>P. discolor </it>is located at parieto-temporal portions of the neocortex. It covers a rostro-caudal range of about 4800 μm and a medio-lateral distance of about 7000 μm on the flattened cortical surface.</p> <p>The auditory cortices of ten adult <it>P. discolor </it>were electrophysiologically mapped in detail. Responses of 849 units (single neurons and neuronal clusters up to three neurons) to pure tone stimulation were recorded extracellularly. Cortical units were characterized and classified depending on their response properties such as best frequency, auditory threshold, first spike latency, response duration, width and shape of the frequency response area and binaural interactions.</p> <p>Based on neurophysiological and neuroanatomical criteria, the auditory cortex of <it>P. discolor </it>could be subdivided into anterior and posterior ventral fields and anterior and posterior dorsal fields. The representation of response properties within the different auditory cortical fields was analyzed in detail. The two ventral fields were distinguished by their tonotopic organization with opposing frequency gradients. The dorsal cortical fields were not tonotopically organized but contained neurons that were responsive to high frequencies only.</p> <p>Conclusion</p> <p>The auditory cortex of <it>P. discolor </it>resembles the auditory cortex of other phyllostomid bats in size and basic functional organization. The tonotopically organized posterior ventral field might represent the primary auditory cortex and the tonotopically organized anterior ventral field seems to be similar to the anterior auditory field of other mammals. As most energy of the echolocation pulse of <it>P. discolor </it>is contained in the high-frequency range, the non-tonotopically organized high-frequency dorsal region seems to be particularly important for echolocation.</p

    Upregulation of pirin expression by chronic cigarette smoking is associated with bronchial epithelial cell apoptosis

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    BACKGROUND: Cigarette smoke disrupts the protective barrier established by the airway epithelium through direct damage to the epithelial cells, leading to cell death. Since the morphology of the airway epithelium of smokers does not typically demonstrate necrosis, the most likely mechanism for epithelial cell death in response to cigarette smoke is apoptosis. We hypothesized that cigarette smoke directly up-regulates expression of apoptotic genes, which could play a role in airway epithelial apoptosis. METHODS: Microarray analysis of airway epithelium obtained by bronchoscopy on matched cohorts of 13 phenotypically normal smokers and 9 non-smokers was used to identify specific genes modulated by smoking that were associated with apoptosis. Among the up-regulated apoptotic genes was pirin (3.1-fold, p < 0.002), an iron-binding nuclear protein and transcription cofactor. In vitro studies using human bronchial cells exposed to cigarette smoke extract (CSE) and an adenovirus vector encoding the pirin cDNA (AdPirin) were performed to test the direct effect of cigarette smoke on pirin expression and the effect of pirin expression on apoptosis. RESULTS: Quantitative TaqMan RT-PCR confirmed a 2-fold increase in pirin expression in the airway epithelium of smokers compared to non-smokers (p < 0.02). CSE applied to primary human bronchial epithelial cell cultures demonstrated that pirin mRNA levels increase in a time-and concentration-dependent manner (p < 0.03, all conditions compared to controls). Overexpression of pirin, using the vector AdPirin, in human bronchial epithelial cells was associated with an increase in the number of apoptotic cells assessed by both TUNEL assay (5-fold, p < 0.01) and ELISA for cytoplasmic nucleosomes (19.3-fold, p < 0.01) compared to control adenovirus vector. CONCLUSION: These observations suggest that up-regulation of pirin may represent one mechanism by which cigarette smoke induces apoptosis in the airway epithelium, an observation that has implications for the pathogenesis of cigarette smoke-induced diseases

    Widespread impact of horizontal gene transfer on plant colonization of land

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    In complex multicellular eukaryotes such as animals and plants, horizontal gene transfer is commonly considered rare with very limited evolutionary significance. Here we show that horizontal gene transfer is a dynamic process occurring frequently in the early evolution of land plants. Our genome analyses of the moss Physcomitrella patens identified 57 families of nuclear genes that were acquired from prokaryotes, fungi or viruses. Many of these gene families were transferred to the ancestors of green or land plants. Available experimental evidence shows that these anciently acquired genes are involved in some essential or plant-specific activities such as xylem formation, plant defence, nitrogen recycling as well as the biosynthesis of starch, polyamines, hormones and glutathione. These findings suggest that horizontal gene transfer had a critical role in the transition of plants from aquatic to terrestrial environments. On the basis of these findings, we propose a model of horizontal gene transfer mechanism in nonvascular and seedless vascular plants
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