Relay exchanges in elite short track speed skating

In short track speed skating, the relay exchange provides an additional strategic component to races by allowing a team to change the skater involved in the pack race. Typically executed every 1 ½ laps, it is the belief of skaters and coaches that during this period of the race, time can be gained or lost due to the execution of the relay exchange. As such, the aim of this study was to examine the influence of the relay exchange on a team's progression through a 5000 m relay race. Using data collected from three World Cup relay events during the 2012-13 season, the time taken to complete the straight for the scenarios with and without the relay exchange were compared at different skating speeds for the corner exit prior to the straight. Overall, the influence of the relay exchange was found to be dependent on this corner exit speed. At slower corner exit speeds (12.01 - 13.5 m/s), relay exchange straight times were significantly faster than the free skating scenario (P < 0.01). Whilst at faster corner exit speeds (14.01 - 15 m/s), straight times were significantly slower (P < 0.001). The findings of this study suggest that the current norm of executing relay exchanges every 1 ½ laps may not be optimal. Instead, varying the frequency of relay exchange execution throughout the race could allow: (1) time to be gained relative to other teams; and (2) facilitate other race strategies by providing an improved opportunity to overtake

Climbing depth-bounded adjacent discrepancy search for solving hybrid flow shop scheduling problems with multiprocessor tasks

This paper considers multiprocessor task scheduling in a multistage hybrid flow-shop environment. The problem even in its simplest form is NP-hard in the strong sense. The great deal of interest for this problem, besides its theoretical complexity, is animated by needs of various manufacturing and computing systems. We propose a new approach based on limited discrepancy search to solve the problem. Our method is tested with reference to a proposed lower bound as well as the best-known solutions in literature. Computational results show that the developed approach is efficient in particular for large-size problems

Association patterns and foraging behaviour in natural and artificial guppy shoals

Animal groups are often nonrandom assemblages of individuals that tend to be assorted by factors such as sex, body size, relatedness and familiarity. Laboratory studies using fish have shown that familiarity among shoal members confers a number of benefits to individuals, such as increased foraging success. However, it is unclear whether fish in natural shoals obtain these benefits through association with familiars. We investigated whether naturally occurring shoals of guppies, Poecilia reticulata, are more adept at learning a novel foraging task than artificial (in which we selected shoal members randomly) shoals. We used social network analysis to compare the structures of natural and artificial shoals and examined whether shoal organization predicts patterns of foraging behaviour. Fish in natural shoals benefited from increased success in the novel foraging task compared with fish in artificial shoals. Individuals in natural shoals showed a reduced latency to approach the novel feeder, followed more and formed smaller subgroups compared to artificial shoals. Our findings show that fish in natural shoals do gain foraging benefits and that this may be facilitated by a reduced perception of risk among familiarized individuals and/or enhanced social learning mediated by following other individuals and small group sizes. Although the structure of shoals was stable over time, we found no direct relationship between shoal social structure and patterns of foraging behaviour

Metagenetic analysis of patterns of distribution and diversity of marine meiobenthic eukaryotes

AimMeiofaunal communities that inhabit the marine benthos offer unique opportunities to simultaneously study the macroecology of numerous phyla that exhibit different life-history strategies. Here, we ask: (1) if the macroecology of meiobenthic communities is explained mainly by dispersal constraints or by environmental conditions; and (2) if levels of meiofaunal diversity surpass existing estimates based on morphological taxonomy. LocationUK and mainland European coast. MethodsNext-generation sequencing techniques (NGS; Roche 454 FLX platform) using 18S nuclear small subunit ribosomal DNA (rDNA) gene. Pyrosequences were analysed using AmpliconNoise followed by chimera removal using Perseus. ResultsRarefaction curves revealed that sampling saturation was only reached at 15% of sites, highlighting that the bulk of meiofaunal diversity is yet to be discovered. Overall, 1353 OTUs were recovered and assigned to 23 different phyla. The majority of sampled sites had c. 60-70 unique operational taxonomic units (OTUs) per site, indicating high levels of beta diversity. The environmental parameters that best explained community structure were seawater temperature, geographical distance and sediment size, but most of the variability (R-2=70%-80%) remains unexplained. Main conclusionsHigh percentages of endemic OTUs suggest that meiobenthic community composition is partly niche-driven, as observed in larger organisms, but also shares macroecological features of microorganisms by showing high levels of cosmopolitanism (albeit on a much smaller scale). Meiobenthic communities exhibited patterns of isolation by distance as well as associations between niche, latitude and temperature, indicating that meiobenthic communities result from a combination of niche assembly and dispersal processes. Conversely, isolation-by-distance patterns were not identified in the featured protists, suggesting that animals and protists adhere to radically different macroecological processes, linked to life-history strategies.Natural Environment Research Council (NERC) [NE/E001505/1, NE/F001266/1, MGF-167]; Portuguese Foundation for Science and Technology (FCT) [SFRH/BD/27413/2006, SFRH/BPD/80447/2014]; EPSRC [EP/H003851/1]; BBSRC CASE studentship; Unilever; Biotechnology and Biological Sciences Research Council [987347]; Engineering and Physical Sciences Research Council [EP/H003851/1]; Natural Environment Research Council [NE/F001290/1, NE/F001266/1, NE/E001505/1, NBAF010002]info:eu-repo/semantics/publishedVersio

Influence of Caloric Expenditure on Postprandial Triglyceride and Glucose Responses Following a High-Carbohydrate Meal

Purpose: To examine the effects of aerobic exercise expending 350 and 700 kcal of energy on postprandial triglyceride (Tg) and glucose responses following a high carbohydrate (CHO) meal. Methods: Non-active individuals (n=9 women/4 men; age=22.8±3.7 yrs; Ht=169±10.4 cm; Wt=75.7± 22.4 kg; BMI=26.1±5.8 kg/m2; VO2 max=34.1±6.9 ml/kg/min) completed three trials in a random order: 1) control trial, 2) single exercise session expending 350 kcal (EX350), and 3) single exercise session expending 700 kcal (EX700). Exercise consisted of treadmill walking at 60% VO2 max until 350 and 700 kcal of energy had been expended. The control session consisted of seated rest. The morning after each experimental session, a fasting (12hr) blood sample was collected followed by consumption of a high-CHO liquid meal (2.44 g/kg of fat free mass (CHO), 0.33 g/kg FFM fat, and 0.56 g/kg FFM protein. Blood was collected again at 1, 2, 3, 4, 5, and 6 hrs post-meal and analyzed for (Tg) and glucose concentrations. The areas under the curve (AUC) were calculated for both (Tg) and glucose concentrations. A repeated measures ANOVA was used to determine statistical significance (p\u3c0.05). Results: Baseline glucose concentrations were not different between trials (p=0.71). Postprandial AUC for glucose concentrations were not different between trials (p=0.38). Baseline Tg concentrations were not altered with exercise (p=.94) of 350 kcal (102.7±77.1 mg/dl) or 700 kcal (112.2±80.6 mg/dl) when compared with rest (115.3±113.9 mg/dl). Postprandial Tg concentrations following rest (937.3± 928.4 mg/dl) were not altered (p=0.37) following exercise of 350 kcal (807.1±605.1 mg/dl) or 700 kcal (867.3±672.6). Conclusion: The glucose and Tg responses following a high-CHO meal were unaffected by a prior exercise session. These results are in contrast to previous investigations that have used high-fat test meals demonstrating that a single bout of exercise reduces the postprandial Tg response. Substantial inter-subject variability was seen in the postprandial Tg responses following exercise ranging from reductions of 27.4% to increments of 17.4%. This study was supported by Texas Woman’s University’s Research Enhancement Program

Measuring straight time in elite short track speed skating relays

In short track speed skating, the relay exchange provides an additional strategic component to races by allowing a team to change the skater involved in the pack race. It is thought that during this period of the race, time can be gained or lost due to the execution of the relay exchange. However, the only temporal measurement reported in short track speed skating is lap time, of which the relay exchange accounts for less than 30 %. As such, a more appropriate measurement of relay exchange performance might be the time taken to complete the straight where the relay exchange was executed. The aim of this study, therefore, was to validate a method for measuring straight time during elite short track speed skating relays. The proposed method used a single HD camcorder to create virtual timing gates at the start and end of both straights. To validate the method, straight times measured using the single HD camcorder were compared to synchronised cameras located perpendicular to the virtual timing gates. The root mean square error for both near and far straight times was less than the temporal resolution of the camera. In addition, Bland-Altman plots showed that the single HD camcorder method was invariant to race speed. Collectively, these findings suggest that a single HD camcorder does provide a valid method for measuring straight times during elite short track speed skating relays

Conservative Treatment for Patients with Suspected SLAP Tears: A Case Series

Objective: Outcome following non-operative management of superior labral anterior to posterior (SLAP) lesions has been under reported with little empirical data demonstrating the effectiveness of conservative treatment. Material and Methods: 10 patients, 5 matched pairs, presenting with symptoms consistent with a SLAP lesion performed a standardized phased rehabilitation program completing patient reported outcome (PRO) and pain measures before and following rehabilitation. Physical therapy notes and home exercise logs were reviewed and all exercises were recorded and coded using the phased rehabilitation protocol as a guide. At followup, patients were divided into two groups; responders and non-responders to treatment based on PRO. The volume of exercise and type of exercise performed for each patient were compared using frequency counts. Results: The non-responders did on average 33 more stretching exercises than the responders. The non-responders did on average 21 more scapular orientation exercises than the responders. There were few to no differences in the volume of strengthening exercises between the two groups except responders performed 38 more scapular retraction exercises at shoulder level while non-responders performed 49 more scapular retraction exercises below shoulder level. Conclusions: This case series identified few exercises that were beneficial to patients\u27 responding to conservative intervention but more often identified exercises that were performed that did not facilitate an improved patient outcome. Therapeutic exercises are often the cornerstone of a rehabilitation program, yet limited evidence exists in which specific exercises are beneficial or not beneficial in patients with symptoms consistent with a SLAP lesion

Microvascular pericyte contractility in vitro: comparison with other cells of the vascular wall

Collagen lattices containing bovine retinal pericytes (RPs), vascular smooth muscle cells (VSMCs), pulmonary microvessel endothelial cells (PMECs), or aortic endothelial cells (AECs) were prepared and contraction was quantitated by measuring the resulting change in lattice area. VSMCs were the most efficient at lattice contraction followed by RPs and then PMECs. AECs did not contract the lattices. To document further that these observations represent contraction, cells were grown on inert silicone rubber sheets. Substratum wrinkling was indicative of tension development and quantitated as percent of cells contracted. RPs were more contractile than PMECs, and AECs were incapable of developing tension. VSMCs were less contractile than RPs, unlike the comparative contractility observed with the lattice system. Alteration of actin-containing filaments by cytochalasin B significantly reduced RP contraction of silicone rubber and inhibited their contraction of collagen lattices in a dose-dependent manner. Rhodamine-phalloidin staining of contracting RPs revealed microfilament bundle orientations that suggested their association in the force applied for contraction. RP, VSMC and PMEC contraction of collagen lattices was directly proportional to the concentration of fetal calf serum. Also, RP contraction was greater in calf serum than calf plasma-derived serum, an indication that RPs respond to substances that appear continuously and episodically in blood. These in vitro findings support the theory that pericytes in vivo are contractile but that endothelial cells may also contribute to microvascular tonus