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Endurance athletes expend large amounts of energy in prolonged high-intensity exercise and, due to the weight-sensitive nature of most endurance sports, often practice periods of dietary restriction. The Female Athlete Triad and Relative Energy Deficiency in Sport models consider endurance athletes at high-risk for suffering from low energy availability and associated health complications, including an increased chance of bone stress injury. Several studies have examined the effects of low energy availability on various parameters of bone structure and markers of bone (re)modelling; however, there are differences in findings and research methods and critical summaries are lacking. It is difficult for athletes to reduce energy expenditure or increase energy intake (to restore energy availability) in an environment where performance is a priority. Development of an alternative tool to help protect bone health would be beneficial. High-impact exercise can be highly osteogenic and energy efficient; however, at present, it is rarely utilized to promote bone health in endurance athletes. Therefore, with a view to reducing the prevalence of bone stress injury, the objectives of this review are to evaluate the effects of low energy availability on bone health in endurance athletes and explore whether a high-impact exercise intervention may help to prevent those effects from occurring.

PurposeThis study aimed to investigate the impact of short-term low energy availability (LEA) on vascular function in young, regularly menstruating women.MethodsParticipants were 19 women, aged 22.9 ± 4.2 years, with body mass index 18–30 kg·m2. They were divided into two groups and completed two conditions in a crossover design: a 3-day control condition (CON) with an energy availability of 45 kcals·kgFFM−1·day−1 and a 3-day LEA condition of 15 kcals·kgFFM−1 day–1. Assessments were conducted during the early follicular phase of the menstrual cycle. Outcome measures included forearm blood flow (FBF), heart rate, blood pressure, arterial stiffness, resting energy expenditure (REE), metabolic blood markers and body composition.ResultsSignificant time-by-condition interactions were found for resting FBF (p = .004), REE (p = .042), triiodothyronine (p = .006), β-hydroxybutyrate (p = .002) and body mass (p < .001). Resting FBF was 1.43 ± 1.01 and 1.31 ± 0.61 (arbitrary units) at pre and post, respectively, in LEA and 1.52 ± 0.7 and 1.76 ± 0.57 at pre and post in CON. The LEA condition led to a decrease in triiodothyronine (pre: 1.54 ± 0.28, post: 1.29 ± 0.27 ng ml−1), REE (pre: 1588 ± 165, post: 1487 ± 160 kcals day−1) and body mass (pre: 61.4 ± 7.5, post: 59.6 ± 7.3 kg). Changes in resting FBF were significantly correlated with changes in REE in the LEA condition (r = 0.53; p = 0.02).ConclusionShort-term LEA modifies regional blood flow and this might contribute to the observed decreased in REE. Findings emphasize the need for careful management of energy availability in populations at risk of LEA.

Background Full-time employees often exhibit unhealthy 24-hour movement behaviours (i.e., prolonged sedentary behaviour, insufficient physical activity, and inadequate sleep). The workplace provides a unique setting for implementing interventions aimed at changing movement behaviours, but there is limited understanding of the design, implementation and effectiveness of these interventions conducted during paid working time. This review aimed to describe the characteristics and outcomes of movement behaviour interventions conducted as a break from work during paid working time. Methods Five databases (MEDLINE, Web of Science, Scopus, APA PsycInfo, Cochrane Library) were searched from inception to June 2024. Inclusion criteria consisted of: (1) adults in full-time employment, (2) interventions that included a break from work allocated to changing movement behaviour(s), and (3) breaks that occurred during paid working time, not during pre-existing breaks. Results Of 168 articles included, 134 (79.8%) were physical activity, 28 (16.7%) were sedentary behaviour, and 6 (3.6%) were sleep interventions. Studies were predominantly randomised controlled trials ( n  = 101, 60.1%), conducted in high-income countries ( n  = 136, 81.0%), and involved white-collar employees ( n  = 139, 82.7%) from office/administrative ( n  = 79, 47.0%) and healthcare ( n  = 27, 16.1%) professions. Positive effects on primary outcomes were reported in 85.1% of physical activity and 85.7% of sedentary behaviour interventions. Conclusion Despite heterogeneity in designs and outcomes, interventions targeting physical activity and sedentary behaviour largely showed promising results. However, the predominance of studies conducted in high-income countries and among white-collar employees may limit generalisability. Future interventions should focus on scalability and allow employees greater autonomy to choose movement behaviour(s) based on individual preferences/needs. Further research is needed to determine the effectiveness of sleep interventions, particularly in identifying implementation barriers. Protocol registration Open Science Framework ( https://osf.io/m9w5t ).

Purpose To examine the dose–response effects of acute glutamine supplementation on markers of gastrointestinal (GI) permeability, damage and, secondary, subjective symptoms of GI discomfort in response to running in the heat. Methods Ten recreationally active males completed a total of four exercise trials; a placebo trial and three glutamine trials at 0.25, 0.5 and 0.9 g kg −1 of fat-free mass (FFM) consumed 2 h before exercise. Each exercise trial consisted of a 60-min treadmill run at 70% of V ˙ O 2max in an environmental chamber set at 30 °C. GI permeability was measured using ratio of lactulose to rhamnose (L:R) in serum. Plasma glutamine and intestinal fatty acid binding protein (I-FABP) concentrations were determined pre and post exercise. Subjective GI symptoms were assessed 45 min and 24 h post-exercise. Results Relative to placebo, L:R was likely lower following 0.25 g kg −1 (mean difference: − 0.023; ± 0.021) and 0.5 g kg −1 (− 0.019; ± 0.019) and very likely following 0.9 g kg − 1 (− 0.034; ± 0.024). GI symptoms were typically low and there was no effect of supplementation. Discussion Acute oral glutamine consumption attenuates GI permeability relative to placebo even at lower doses of 0.25 g kg −1 , although larger doses may be more effective. It remains unclear if this will lead to reductions in GI symptoms. Athletes competing in the heat may, therefore, benefit from acute glutamine supplementation prior to exercise in order to maintain gastrointestinal integrity.

My dissertation consists of three essays on econometric forecasting and forecast evaluation. Each essay contributes to the literature in its own way. In the first essay, I employ a common qualitative analysis framework on a widely-available consensus forecast. I evaluate the consensus forecast's performance using the Predictive Failure statistic. I find that the survey respondents provide statistically significant directional forecasts or signals. The second essay evaluates forecasts of a prominent energy policy model. This includes analysis of the forecasts, developing a rival forecasting model, and attempting to identify information to improve the policy model's forecasts. This analysis finds that the policy model generally performs well against a sophisticated time-series model. Specifically, the model appears to incorporate data dynamics appropriately, and this technique can serve as a new benchmark to evaluate the forecasts. The third essay examines the role of data revisions on models employing error correction relationships. These error correction relationships are rooted in economic theory and thus should be robust to changing economic conditions and data revisions. This essay finds that an older, popular model breaks down using newer data vintages, suggesting that data revisions and data issues can influence the stability of vector error correction models.

The purpose of this dissertation is to determine the agent(s) of accumulation for the fossil bone assemblages from Bundu Farm and Pniel 6, two Middle Stone Age (MSA), open-air archaeological sites located near seasonal bodies of water in the Northern Cape Province, South Africa. A primary goal is to further establish the relationship between the early MSA artifacts and faunal remains recovered from the sites, and to determine whether that association indicates hominin hunting or primary access to carcasses, or secondary scavenging from non-hominin carnivore kills and other natural death events. The wider objective is to expand our current understanding of hominin subsistence behaviors during this important period of human evolution, models of which are largely based on evidence inferred from coastal cave archaeological sites. For comparison, I detail the modern bone accumulations resulting from carnivore serial predation surrounding a complex of seasonal waterholes at Ngamo Pan, located in Hwange National Park, Zimbabwe. As both hominin and non-hominin carnivore influence is to be expected at open-air bone assemblages, the actualistic studies at Ngamo Pan provide baseline measures for which to determine the relative impacts of those agents of accumulation at Bundu Farm, Pniel 6, and other open-air archaeological sites. The Bundu Farm pan site, dating to roughly 245 ka, preserved zooarchaeological and taphonomic features in the faunal assemblage indicative of early access to animal carcasses by early MSA hominins, followed by secondary scavenging by non-hominin carnivores. The faunal assemblage from the Pniel 6 riverine site, tentatively dated ∼243-300 ka, yielded evidence to suggest secondary scavenging by early MSA hominins from carnivore kills or other natural deaths. Similar to many MSA coastal cave sites, these open-air sites within the interior of southern Africa show variability among hominin subsistence behaviors, but patterns consistent with adaptations to more marginal grassland environments as opposed to the relatively more wet and productive coastal environments. The open grassland expanse surrounding Ngamo Pan serves as fitting analog to interpret the processes of natural bone accumulation in these environments. The modern bone assemblages resulting from carnivore serial predation at Ngamo Pan included many of the same patterns shown at Bundu Farm and Pniel 6, thus there is a limited set of variables that can be used to distinguish between hominin and non-hominin carnivore bone accumulations at open-air archaeological sites. Analyses that can distinguish between the two agents of accumulation are mortality profiles, correlations between limb bone density and carnivore feeding behaviors, and hominin and non-hominin carnivore bone surface modifications. Measures that provide ambiguous results include site location and bone distribution, species representation, raw skeletal part representation, correlations with hunter-gatherer transport decisions, trampling and weathering damage, and bone breakage patterns.

Drawing on the large body of taphonomic, ethnoarchaeological, and general zooarchaeological literature currently available, the main goal of this research report is to provide the first comprehensive taphonomic account of the fauna at Kalkbank in order to establish whether humans, carnivores, or other natural processes were the major accumulators of the assemblage.Through examination of species presence and abundance, patterns of bone breakage, various surface modifications to the bones, several aspects of skeletal part representation, and mortality profiles, it has been proven that carnivores were the main agent of accumulation. Furthermore, it has been determined that the site accumulated sometime during the late Pleistocene, but closely resembles several open-air sites dated from the Acheulean.

Differential expression analysis in single-cell transcriptomics enables the dissection of cell-type-specific responses to perturbations such as disease, trauma, or experimental manipulations. While many statistical methods are available to identify differentially expressed genes, the principles that distinguish these methods and their performance remain unclear. Here, we show that the relative performance of these methods is contingent on their ability to account for variation between biological replicates. Methods that ignore this inevitable variation are biased and prone to false discoveries. Indeed, the most widely used methods can discover hundreds of differentially expressed genes in the absence of biological differences. To exemplify these principles, we exposed true and false discoveries of differentially expressed genes in the injured mouse spinal cord. Differential expression analysis of single-cell transcriptomics allows scientists to dissect cell-type-specific responses to biological perturbations. Here, the authors show that many commonly used methods are biased and can produce false discoveries.

A spinal cord injury disrupts communication between the brain and the circuits in the spinal cord that regulate neurological functions. The consequences are permanent paralysis, loss of sensation and debilitating dysautonomia. However, the majority of circuits located above and below the injury remain anatomically intact, and these circuits can reorganize naturally to improve function. In addition, various neuromodulation therapies have tapped into these processes to further augment recovery. Emerging research is illuminating the requirements to reconstitute damaged circuits. Here, we summarize these natural and targeted reorganizations of circuits after a spinal cord injury. We also advocate for new concepts of reorganizing circuits informed by multi-omic single-cell atlases of recovery from injury. These atlases will uncover the molecular logic that governs the selection of 'recovery-organizing' neuronal subpopulations, and are poised to herald a new era in spinal cord medicine.The authors summarize changes in circuits after spinal cord injury and current strategies to target these circuits in order to improve recovery, but also advocate for new concepts of reorganizing circuits informed by multi-omic single-cell atlases.