2,661 research outputs found
Exploring internal child sex trafficking networks using social network analysis
This article explores the potential of social network analysis as a tool in supporting the investigation of internal child sex trafficking in the UK. In doing so, it uses only data, software, and training already available to UK police. Data from two major operations are analysed using in-built centrality metrics, designed to measure a network’s overarching structural properties and identify particularly powerful individuals. This work addresses victim networks alongside offender networks. The insights generated by SNA inform ideas for targeted interventions based on the principles of Situational Crime Prevention. These harm-reduction initiatives go beyond traditional enforcement to cover prevention, disruption, prosecution, etc. This article ends by discussing how SNA can be applied and further developed by frontline policing, strategic policing, prosecution, and policy and research
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Beyond dichotomies in reinforcement learning
Reinforcement learning (RL) is a framework of particular importance to psychology, neuroscience and machine learning. Interactions between these fields, as promoted through the common hub of RL, has facilitated paradigm shifts that relate multiple levels of analysis in a singular framework (for example, relating dopamine function to a computationally defined RL signal). Recently, more sophisticated RL algorithms have been proposed to better account for human learning, and in particular its oft-documented reliance on two separable systems: a model-based (MB) system and a model-free (MF) system. However, along with many benefits, this dichotomous lens can distort questions, and may contribute to an unnecessarily narrow perspective on learning and decision-making. Here, we outline some of the consequences that come from overconfidently mapping algorithms, such as MB versus MF RL, with putative cognitive processes. We argue that the field is well positioned to move beyond simplistic dichotomies, and we propose a means of refocusing research questions towards the rich and complex components that comprise learning and decision-making
Whole body cryotherapy, cold water immersion, or a placebo following resistance exercise: a case of mind over matter?
PURPOSE: The use of cryotherapy as a recovery intervention is prevalent amongst athletes. Performance of high volume, heavy load resistance exercise is known to result in disturbances of muscle function, perceptual responses and blood borne parameters. Therefore, this study investigated the influence of cold water immersion (CWI), whole body cryotherapy (WBC) or a placebo (PL) intervention on markers of recovery following an acute resistance training session.
METHODS: 24 resistance trained males were matched into a CWI (10 min at 10 °C), WBC (3- and 4 min at - 85 °C) or PL group before completing a lower body resistance training session. Perceptions of soreness and training stress, markers of muscle function, inflammation and efflux of intracellular proteins were assessed before, and up to 72 h post exercise.
RESULTS: The training session resulted in increased soreness, disturbances of muscle function, and increased inflammation and efflux of intracellular proteins. Although WBC attenuated soreness at 24 h, and positively influenced peak force at 48 h compared to CWI and PL, many of the remaining outcomes were trivial, unclear or favoured the PL condition. With the exception of CRP at 24 h, neither cryotherapy intervention attenuated the inflammatory response compared to PL.
CONCLUSION: There was some evidence to suggest that WBC is more effective than CWI at attenuating select perceptual and functional responses following resistance training. However, neither cryotherapy intervention was more effective than the placebo treatment at accelerating recovery. The implications of these findings should be carefully considered by individuals employing cryotherapy as a recovery strategy following heavy load resistance training
The influence of repeated cold water immersion on adaptations to strength and power training
Introduction
Cold Water Immersion (CWI) is a popular recovery strategy utilised by athletes in order to attenuate the negative influence of strenuous exercise on subsequent performance. One of the proposed physiological mechanisms underpinning the use of CWI is the potential to limit the inflammatory response after acute exercise. Given that the inflammatory cascade ultimately leads to muscle regeneration and repair, it is pertinent to investigate the longer term impact of regular cryotherapy exposure on adaptations to strength and power training.
Methods
Thirteen resistance trained males (mean age 25.8 ± 5.5 years; height 1.8 ± 0.1 m; mass 83.6 ± 15.7 kg; 4RM back squat 146.2 ± 38.5 kg) completed an 8 week (1 x 4 week strength and 1 x 4 week power block) lower body resistance training program. Participants were match-paired into either the CWI (10 min at 10° ± 0.5°) or placebo group based on a ratio of lean mass to 4RM back squat. Participants completed 2 training sessions per week and completed their allocated recovery intervention after each training session. Measures of muscle fibre pennation angle, maximal voluntary isometric contraction (MVIC) at 90°, peak torque of the knee extensors (60deg∙s), and isometric squat parameters (peak force and rate of force development (RFD))were measured at baseline, midpoint and post training intervention. Results were analysed using magnitude based inferences.
Results
At the post testing session, CWI demonstrated a likely moderate harmful effect on muscle fibre pennation angle compared to the placebo group (CWI: 11.4; ±4.8%; placebo: 21.5; ±8.4%). However, CWI demonstrated a likely large beneficial effect on peak torque (60deg∙s) compared to the placebo group (CWI: 7.5; ±6.5%; placebo: -2.4; ±4.0%) at midpoint. There were trivial differences between groups for isometric peak force and peak torque (60deg∙s) from baseline to post. All other effects were unclear.
Discussion
The greater increase in muscle fibre pennation angle in the placebo group compared to the CWI group would indicate a greater increase lean muscle mass. However, CWI still demonstrated a positive impact on peak torque at 60 deg∙s compared to the placebo group. Blood sample analyses are ongoing and may offer further insight into the underpinning mechanisms. Further investigation is warranted to better understand the potential negative impact of repeated cryotherapy exposure on functional adaptations to strength and power training stimuli
Assessment of energy intake and energy expenditure of male adolescent academy-level soccer players during a competitive week
This study investigated the energy intake and expenditure of professional adolescent academy-level soccer players during a competitive week. Over a seven day period that included four training days, two rest days and a match day, energy intake (self-reported weighed food diary and 24-h recall) and expenditure (tri-axial accelerometry) were recorded in 10 male players from a professional English Premier League club. The mean macronutrient composition of the dietary intake was 318 ± 24 g·day−1 (5.6 ± 0.4 g·kg−1 BM) carbohydrate, 86 ± 10 g·day−1 (1.5 ± 0.2 g·kg−1 BM) protein and 70 ± 7 g·day−1 (1.2 ± 0.1 g·kg−1 BM) fats, representing 55% ± 3%, 16% ± 1%, and 29% ± 2% of mean daily energy intake respectively. A mean daily energy deficit of −1302 ± 1662 kJ (p = 0.035) was observed between energy intake (9395 ± 1344 kJ) and energy expenditure (10679 ± 1026 kJ). Match days (−2278 ± 2307 kJ, p = 0.012) and heavy training days (−2114 ± 2257 kJ, p = 0.016) elicited the greatest deficits between intake and expenditure. In conclusion, the mean daily energy intake of professional adolescent academy-level soccer players was lower than the energy expended during a competitive week. The magnitudes of these deficits were greatest on match and heavy training days. These findings may have both short and long term implications on the performance and physical development of adolescent soccer players
The effect of milk on recovery from repeat-sprint cycling in female team-sport athletes
The consumption of milk post-eccentric exercise attenuates the effects of muscle damage in team-sport athletes. However, participation in team sport involves both concentric-eccentric loading and metabolic stress. Therefore, the aim of this study was to investigate the effects of post-exercise milk consumption on recovery from a cycling protocol designed to simulate the metabolic demands of team sport. Ten female team-sport athletes participated in a randomised cross-over investigation. Upon completion of the protocol participants consumed 500ml of milk (MILK) or 500ml of an energy-matched carbohydrate (CHO) drink. Muscle function (peak torque, rate of force development (RFD), countermovement jump (CMJ), 20m sprint, muscle soreness and tiredness, serum creatine kinase (CK), (high-sensitivity C reactive protein (hsCRP) and measures of oxidative stress (protein carbonyls (PC) and GSH:GSSG (oxidized glutathione:reduced glutathione) ratio) were determined pre-, 24h, 48h and 72h post-exercise. MILK had a possible beneficial effect in attenuating losses in peak torque (180 s) from baseline to 24h (3.2±7.8% v -6.2±7.5%, MILK v CHO) and a possible beneficial effect in minimising soreness (baseline-48h; baseline-72h) and tiredness (baseline-24h; baseline-72h). There was no change in oxidative stress following the exercise protocol, though a likely benefit of milk was observed for GSH:GSSH ratio at baseline-24h (0.369 x/÷ 1.89, 1.103 x/÷ 3.96, MILK v CHO). MILK had an unclear effect on all other variables. Consumption of 500ml milk post-repeat sprint cycling had little to no benefit in minimising losses in peak torque, or minimising increases in soreness and tiredness and had no effect on serum markers of muscle damage and inflammation
Fluctuating and dissipative dynamics of dark solitons in quasi-condensates
The fluctuating and dissipative dynamics of matter-wave dark solitons within
harmonically trapped, partially condensed Bose gases is studied both
numerically and analytically. A study of the stochastic Gross-Pitaevskii
equation, which correctly accounts for density and phase fluctuations at finite
temperatures, reveals dark soliton decay times to be lognormally distributed at
each temperature, thereby characterizing the previously predicted long lived
soliton trajectories within each ensemble of numerical realizations (S.P.
Cockburn {\it et al.}, Phys. Rev. Lett. 104, 174101 (2010)). Expectation values
for the average soliton lifetimes extracted from these distributions are found
to agree well with both numerical and analytic predictions based upon the
dissipative Gross-Pitaevskii model (with the same {\it ab initio} damping).
Probing the regime for which , we find average
soliton lifetimes to scale with temperature as , in agreement
with predictions previously made for the low-temperature regime .
The model is also shown to capture the experimentally-relevant decrease in the
visibility of an oscillating soliton due to the presence of background
fluctuations.Comment: 17 pages, 14 figure
Matter-wave dark solitons: stochastic vs. analytical results
The dynamics of dark matter-wave solitons in elongated atomic condensates are
discussed at finite temperatures. Simulations with the stochastic
Gross-Pitaevskii equation reveal a noticeable, experimentally observable spread
in individual soliton trajectories, attributed to inherent fluctuations in both
phase and density of the underlying medium. Averaging over a number of such
trajectories (as done in experiments) washes out such background fluctuations,
revealing a well-defined temperature-dependent temporal growth in the
oscillation amplitude. The average soliton dynamics is well captured by the
simpler dissipative Gross-Pitaevskii equation, both numerically and via an
analytically-derived equation for the soliton center based on perturbation
theory for dark solitons.Comment: 4 pages, 3 figures. Added several reference
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