346 research outputs found

    Alternative communication network designs for an operational Plato 4 CAI system

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    The cost of alternative communications networks for the dissemination of PLATO IV computer-aided instruction (CAI) was studied. Four communication techniques are compared: leased telephone lines, satellite communication, UHF TV, and low-power microwave radio. For each network design, costs per student contact hour are computed. These costs are derived as functions of student population density, a parameter which can be calculated from census data for one potential market for CAI, the public primary and secondary schools. Calculating costs in this way allows one to determine which of the four communications alternatives can serve this market least expensively for any given area in the U.S. The analysis indicates that radio distribution techniques are cost optimum over a wide range of conditions

    Difference Amongst Your Own: The Lived Experiences Of Low-Income African-American Students and Their Encounters With Class Within Elite Historically Black College (HBCU) Environments

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    The subtle and deeply impactful nuances of Black intra-racial social class differences that manifest amongst students who attend historically Black colleges (HBCU) has remained untouched and understudied in higher-education scholarship. In this phenomenological study, I explore how low-income African-American students encounter social class within elite HBCU environments. The men and women in this study graduated between the years of 2001 and 2010. Contemporary HBCU student experiences are underscored and reveal great tension between self, community, and place. The philosophical works of Martin Heidegger, Hans-Georg Gadamer and Edward Casey are joined with the voices of Black scholars including W.E.B. DuBois, Audre Lorde, Frantz Fanon, bell hooks, and Toni Morrison to provide critical context for the phenomenon being studied. Max van Manen’s key phenomenological insights also provide a methodological foundation for the study. My co-researchers encountered significant shifts and evolved within their oppressed identities during their undergraduate years. During their undergraduate years they felt a difference amongst their own that they still reconcile today. The participants within this study endured feelings of alienation, wonder, and even confusion within their distinct higher education environments. This study concludes with phenomenological insights for myriad educational stakeholders that include higher educational researchers, higher education practitioners, families, and students. I provide pedagogical insights into how elite HBCU environments can not only intercede and provide a more enriching cultural environment for their low-income students, but their families as well. The pedagogical insights that “end” this study also summon the need for future research to continue to explore Black intra-racial differences that are present within both elite HBCU communities and elite PWI institutions as well. Exposure to the pertinent issues that are outlined in this scholarship provide a new entry into critical discourses that must now be had. This dialogue is needed so that students within elite HBCU environments do not continue to suffer in silence within their oppressed identities

    An Unusual Reaction and Other Observations of Sperm Whales Near Fixed-Wing Aircraft

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    Reported behavioral reactions by sperm whales to aircraft are sparse, highly variable, and largely anecdotal as summarized below. Observers since the whaling era began have noted that sperm whales tend to be skittish (Whitehead 2003). When documented, sperm whale reactions to both planes and helicopters range from no reaction (Clarke 1956, Gambell 1968, Green et al. 1992) to reactions such as increased surface intervals and dramatic behavioral changes (Clarke 1956, Fritts et al. 1983, Mullin et al. 1991, Würsig et al. 1998, Richter et al. 2003, 2006). Given the lack of supporting data for either case, it is important that these types of data are collected and consolidated into a cohesive document. Therefore, the specific objectives of our paper are to report our visual observations of sperm whale reactions to straight-line aircraft fly-bys (i.e., passes), to report a unique observation of a recognized “stress behavioral reaction” exhibited by sperm whales during an overhead circling by small fixed-wing aircraft, and to provide a summary review of published related studies

    Evidence of MyomiR Regulation of the Pentose Phosphate Pathway during Mechanical Load-Induced Hypertrophy

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    Many of the molecular and cellular mechanisms discovered to regulate skeletal muscle hypertrophy were first identified using the rodent synergist ablation model. This model reveals the intrinsic capability and necessary pathways of skeletal muscle growth in response to mechanical overload (MOV). Reminiscent of the rapid cellular growth observed with cancer, we hypothesized that in response to MOV, skeletal muscle would undergo metabolic programming to sustain increased demands to support hypertrophy. To test this hypothesis, we analyzed the gene expression of specific metabolic pathways taken from transcriptomic microarray data of a MOV time course. We found an upregulation of genes involved in the oxidative branch of the pentose phosphate pathways (PPP) and mitochondrial branch of the folate cycle suggesting an increase in the production of NADPH. In addition, we sought to determine the potential role of skeletal muscle-enriched microRNA (myomiRs) and satellite cells in the regulation of the metabolic pathways that changed during MOV. We observed an inverse pattern in gene expression between muscle-enriched myomiR-1 and its known target gene glucose-6-phosphate dehydrogenase, G6pdx, suggesting myomiR regulation of PPP activation in response to MOV. Satellite cell fusion had a significant but modest impact on PPP gene expression. These transcriptomic findings suggest the robust muscle hypertrophy induced by MOV requires enhanced redox metabolism via PPP production of NADPH which is potentially regulated by a myomiR network

    “Selling Sisterhood”: (Re)Viewing White Sorority Women’s Self-Portrayals in Recruitment Videos

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    Amidst the contemporary higher education and student affairs research landscape, there is a critical need to explore how sororities engage social media — specifically how their participation in these particular mediums may reinforce negative stereotypes about these organizations. This qualitative study engaged a content analysis of the top 100 most viewed National Panhellenic Conference (NPC) sorority recruitment videos. Findings highlight how many of these videos overwhelmingly cast strong signals to viewers regarding gender, race, and social class. Findings suggest that researchers and practitioners must better understand how these videos overtly and covertly highlight sorority life on college campuses and the implications therein

    A Novel Tetracycline-Responsive Transgenic Mouse Strain for Skeletal Muscle-Specific Gene Expression

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    Background: The tetracycline-responsive system (Tet-ON/OFF) has proven to be a valuable tool for manipulating gene expression in an inducible, temporal, and tissue-specific manner. The purpose of this study was to create and characterize a new transgenic mouse strain utilizing the human skeletal muscle α-actin (HSA) promoter to drive skeletal muscle-specific expression of the reverse tetracycline transactivator (rtTA) gene which we have designated as the HSA-rtTA mouse. Methods: To confirm the HSA-rtTA mouse was capable of driving skeletal muscle-specific expression, we crossed the HSA-rtTA mouse with the tetracycline-responsive histone H2B-green fluorescent protein (H2B-GFP) transgenic mouse in order to label myonuclei. Results: Reverse transcription-PCR confirmed skeletal muscle-specific expression of rtTA mRNA, while single-fiber analysis showed highly effective GFP labeling of myonuclei in both fast- and slow-twitch skeletal muscles. Pax7 immunohistochemistry of skeletal muscle cross-sections revealed no appreciable GFP expression in satellite cells. Conclusions: The HSA-rtTA transgenic mouse allows for robust, specific, and inducible gene expression across muscles of different fiber types. The HSA-rtTA mouse provides a powerful tool to manipulate gene expression in skeletal muscle

    Bovine Milk Extracellular Vesicles (EVs) Modification Elicits Skeletal Muscle Growth in Rats

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    The current study investigated how bovine milk extracellular vesicles (EVs) affected rotarod performance and biomarkers of skeletal muscle physiology in young, growing rats. Twenty-eight-day Fisher 344 rats were provided an AIN-93G-based diet for 4 weeks that either remained unadulterated [EVs and RNA-sufficient (ERS; n = 12)] or was sonicated [EVs and RNA-depleted (ERD; n = 12)]. Prior to (PRE) and on the last day of the intervention (POST), animals were tested for maximal rotarod performance. Following the feeding period, the gastrocnemius muscle was analyzed at the histological, biochemical, and molecular levels and was also used to measure mitochondrial function and reactive oxygen species (ROS) emission. A main effect of time was observed for rotarod time (PRE \u3e POST, p = 0.001). Terminal gastrocnemius mass was unaffected by diet, although gastrocnemius muscle fiber cross sectional area was 11% greater (p = 0.018) and total RNA (a surrogate of ribosome density) was 24% greater (p = 0.001) in ERD. Transcriptomic analysis of the gastrocnemius indicated that 22 mRNAs were significantly greater in ERS versus ERD (p \u3c 0.01), whereas 55 mRNAs were greater in ERD versus ERS (p \u3c 0.01). There were no differences in gastrocnemius citrate synthase activity or mitochondrial coupling (respiratory control ratio), although mitochondrial ROS production was lower in ERD gastrocnemius (p = 0.016), which may be explained by an increase in glutathione peroxidase protein levels (p = 0.020) in ERD gastrocnemius. Dietary EVs profiling confirmed that sonication in the ERD diet reduced EVs content by ∌60%. Our findings demonstrate that bovine milk EVs depletion through sonication elicits anabolic and transcriptomic effects in the gastrocnemius muscle of rapidly maturing rats. While this did not translate into a functional outcome between diets (i.e., rotarod performance), longer feeding periods may be needed to observe such functional effects

    Resistance training in humans and mechanical overload in rodents do not elevate muscle protein lactylation

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    Although several reports have hypothesized that exercise may increase skeletal muscle protein lactylation, empirical evidence in humans is lacking. Thus, we adopted a multifaceted approach to examine if acute and subchronic resistance training (RT) altered skeletal muscle protein lactylation levels. In mice, we also sought to examine if surgical ablation-induced plantaris hypertrophy coincided with increases in muscle protein lactylation. To examine acute responses, participants’ blood lactate concentrations were assessed before, during, and after eight sets of an exhaustive lower body RT bout (n = 10 trained college-aged men). Vastus lateralis biopsies were also taken before, 3-h post, and 6-h post-exercise to assess muscle protein lactylation. To identify training responses, another cohort of trained college-aged men (n = 14) partook in 6 weeks of lower-body RT (3x/week) and biopsies were obtained before and following the intervention. Five-month-old C57BL/6 mice were subjected to 10 days of plantaris overload (OV, n = 8) or served as age-matched sham surgery controls (Sham, n = 8). Although acute resistance training significantly increased blood lactate responses ~7.2- fold (p \u3c 0.001), cytoplasmic and nuclear protein lactylation levels were not significantly altered at the post-exercise time points, and no putative lactylation-dependent mRNA was altered following exercise. Six weeks of RT did not alter cytoplasmic protein lactylation (p = 0.800) despite significantly increasing VL muscle size (+3.5%, p=0.037), and again, no putative lactylation-dependent mRNA was significantly affected by training. Plantaris muscles were larger in OV versus Sham mice (+43.7%, p \u3c 0.001). However, cytoplasmic protein lactylation was similar between groups (p = 0.369), and nuclear protein lactylation was significantly lower in OV versus Sham mice (p \u3c 0.001). The current null findings, along with other recent null findings in the literature, challenge the thesis that lactate has an appreciable role in promoting skeletal muscle hypertrophy

    Influence of environmental parameters on movements and habitat utilization of humpback whales (Megaptera novaeangliae) in the Madagascar breeding ground

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    © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Royal Society Open Science 3 (2016): 160616, doi:10.1098/rsos.160616.Assessing the movement patterns and key habitat features of breeding humpback whales is a prerequisite for the conservation management of this philopatric species. To investigate the interactions between humpback whale movements and environmental conditions off Madagascar, we deployed 25 satellite tags in the northeast and southwest coast of Madagascar. For each recorded position, we collated estimates of environmental variables and computed two behavioural metrics: behavioural state of ‘transiting’ (consistent/directional) versus ‘localized’ (variable/non-directional), and active swimming speed (i.e. speed relative to the current). On coastal habitats (i.e. bathymetry < 200 m and in adjacent areas), females showed localized behaviour in deep waters (191 ± 20 m) and at large distances (14 ± 0.6 km) from shore, suggesting that their breeding habitat extends beyond the shallowest waters available close to the coastline. Males' active swimming speed decreased in shallow waters, but environmental parameters did not influence their likelihood to exhibit localized movements, which was probably dominated by social factors instead. In oceanic habitats, both males and females showed localized behaviours in shallow waters and favoured high chlorophyll-a concentrations. Active swimming speed accounts for a large proportion of observed movement speed; however, breeding humpback whales probably exploit prevailing ocean currents to maximize displacement. This study provides evidence that coastal areas, generally subject to strong human pressure, remain the core habitat of humpback whales off Madagascar. Our results expand the knowledge of humpback whale habitat use in oceanic habitat and response to variability of environmental factors such as oceanic current and chlorophyll level.Funding was provided by Total Foundation to NeuroPSI, and by individuals and foundations to the WCS Ocean Giants Program
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