Integral-field studies of the high-redshift Universe

We present results from a new method of exploring the distant Universe. We use 3-D spectroscopy to sample a large cosmological volume at a time when the Universe was less than 3 billion years old to investigate the evolution of star-formation activity. Within this study we also discovered a high redshift type-II quasar which would not have been identified with imaging studies alone. This highlights the crucial role that integral-field spectroscopy may play in surveying the distant Universe in the future.Comment: From proceedings of Euro3D Spectroscopy annual RTN network meeting (ed. J. Walsh). 5 pages, accepted for publication in Astron. Nach

Respiratory Syncytial Virus

RSV infection has an estimated global incidence of 33 million cases in children <5 years of age, with 10% requiring hospital admission and up to 199 000 dying of the disease. There is growing evidence that severe infantile RSV bronchiolitis, a condition characterised by an inflammatory reaction to the virus, is associated with later childhood wheeze in some vulnerable children; however, a direct causal relationship with asthma has not yet been established. RSV infection is also increasingly recognised as a cause of morbidity and mortality in those with underlying airway disease, the immunocompromised and frail elderly persons. Novel molecular-based diagnostic tools are becoming established, but treatment remains largely supportive, with palivizumab the only licensed agent currently available for passive prophylaxis of selected pre-term infants. While effective treatments remain elusive, there is optimism about the testing of novel antiviral drugs and the development of vaccines that may induce long-lasting immunity without the risk of disease augmentation

A Selected Ion Flow Tube Study of the Reactions of Several Cations with the Group 6B Hexafluorides SF6, SeF6, and TeF6

The first investigation of the ion chemistry of SeF$_6$ and TeF$_6$ is presented. Using a selected ion flow tube, the thermal rate coefficients and ion product distributions have been determined at 300 K for the reactions of fourteen atomic and molecular cations, namely H$_3$O$^+$, CF$_3^+$, CF$^+$, CF$_2^+$, H$_2$O$^+$, N$_2$O$^+$, O$^+$, CO$_2^+$, CO$^+$, N$^+$, N$_2^+$, Ar$^+$, F$^+$ and Ne$^+$ (in order of increasing recombination energy), with SeF$_6$ and TeF$_6$. The results are compared with those from the reactions of these ions with SF$_6$, for which the reactions with CF$^+$, CF$_2^+$, N$_2$O$^+$ and F$^+$ are reported for the first time. Several distinct processes are observed amongst the large number of reactions studied, including dissociative charge transfer, and F$^-$, F, F$_2^-$ and F$_2$ abstraction from the neutral reactant molecule to the reagent ion. The dissociative charge transfer channels are discussed in relation to vacuum ultraviolet photoelectron and threshold photoelectron-photoion coincidence spectra of XF$_6$ (X = S, Se, and Te). For reagent ions whose recombination energies lie between the first dissociative ionisation limit, XF$_6$ $\rightarrow$ XF$_5^+$ + F + e$^-$, and the onset of ionisation of the XF$_6$ molecule, the results suggest that if dissociative charge transfer occurs, it proceeds via an intimate encounter. For those reagent ions whose recombination energies are greater than the onset of ionisation, long-range electron transfer may occur depending on whether certain physical factors apply, for example non-zero Franck-Condon overlap. From the reaction kinetics, limits for the heats of formation of SeF$_4$, SeF$_5$, TeF$_4$ and TeF$_5$ at 298 K have been obtained; $\Delta_f$H$^o$(SeF$_4$) < -369 kJ mol$^{-1}$, $\Delta_f$H$^o$(SeF$_5$) < -621 kJ mol$^{-1}$, $\Delta_f$H$^o$(TeF$_4$) > -570 kJ mol$^{-1}$, and $\Delta_f$H$^o$(TeF$_5$) < -822 kJ mol$^{-1}$

Resource acquisition, distribution and end-use efficiencies and the growth of industrial society

A key feature of the growth of industrial society is the acquisition of increasing quantities of resources from the environment and their distribution for end use. With respect to energy, growth has been near exponential for the last 160 years. We attempt to show that the global distribution of resources that underpins this growth may be facilitated by the continual development and expansion of near optimal directed networks. If so, the distribution efficiencies of these networks must decline as they expand due to path lengths becoming longer and more tortuous. To maintain long-term exponential growth the physical limits placed on the distribution networks appear to be counteracted by innovations deployed elsewhere in the system: namely at the points of acquisition and end use. We postulate that the maintenance of growth at the specific rate of ~2.4% yr−1 stems from an implicit desire to optimise patterns of energy use over human working lifetimes

The environment and host haloes of the brightest z~6 Lyman-break galaxies

By studying the large-scale structure of the bright high-redshift Lyman-break galaxy (LBG) population it is possible to gain an insight into the role of environment in galaxy formation physics in the early Universe. We measure the clustering of a sample of bright (-22.7<M_UV<-21.125) LBGs at z~6 and use a halo occupation distribution (HOD) model to measure their typical halo masses. We find that the clustering amplitude and corresponding HOD fits suggests that these sources are highly biased (b~8) objects in the densest regions of the high-redshift Universe. Coupled with the observed rapid evolution of the number density of these objects, our results suggest that the shape of high luminosity end of the luminosity function is related to feedback processes or dust obscuration in the early Universe - as opposed to a scenario where these sources are predominantly rare instances of the much more numerous M_UV ~ -19 population of galaxies caught in a particularly vigorous period of star formation. There is a slight tension between the number densities and clustering measurements, which we interpret this as a signal that a refinement of the model halo bias relation at high redshifts or the incorporation of quasi-linear effects may be needed for future attempts at modelling the clustering and number counts. Finally, the difference in number density between the fields (UltraVISTA has a surface density ~1.8 times greater than UDS) is shown to be consistent with the cosmic variance implied by the clustering measurements.Comment: 19 pages, 8 figures, accepted MNRAS 23rd March 201

Kinetic study of adsorption and photo-decolorization of Reactive Red 198 on TiO2 surface

Recycling and reuse of wastewater after purification will reduce the environmental pollution as well as fulfill the increasing demand of water. Adsorption-based water treatment process is very popular for dye-house wastewater treatment. The present study deals with treatment of wastewater contaminated by reactive dye. TiO2 is used as adsorbent and the spent adsorbent has been regenerated by Advanced Oxidation Process (AOP), without using any other chemicals. TiO2 adsorbs dye molecules and then those dye molecules have been oxidized via a photocatalytic reaction in presence of UV irradiation. Kinetics of dye adsorption and photocatalytic oxidation reaction has been developed in this study. Photocatalyst adsorbent (TiO2) has been reused several times after regeneration. The activity of catalyst decreases after each cycle; due to poisoning cause by intermediate by-products. Kinetic of this catalyst deactivation has been incorporated with L–H model to develop the photocatalytic reaction kinetic model

Validity and reliability of strategy metrics to assess countermovement jump performance using the newly developed My Jump Lab smartphone application

The aim of the present study was to analyse the validity and reliability of the newly developed My Jump Lab smartphone app, which includes the option to calculate time to take-off and the reactive strength index modified (RSI_Mod – calculated as jump height divided by time to take-off), in addition to jump height. Twenty-seven postgraduate sport science students attended a single test session and performed three maximal effort countermovement jumps (CMJ) on twin force plates, whilst concurrently being filmed using the app. Results showed no significant differences in jump height between measurement methods (g = 0.00) or RSI_Mod (g = -0.49), although a significant difference was evident for time to take-off (g = 0.68). When a correction factor was applied to time to take-off data, no meaningful differences were evident (g = 0.00), which also had a knock-on effect for RSI_Mod (g = 0.10). Bland-Altman analysis showed near perfect levels of agreement for jump height with a bias estimate of 0.001 m, whilst time to take-off reported a bias estimate of 0.075 s initially and, 0.000 s once the correction factor was applied. For RSI_Mod, bias estimate was initially -0.048, and 0.006 once calculated with the corrected time to take-off data. Pearson’s r correlations were: 0.98 for jump height, 0.81 for time to take-off, and 0.85 for RSI_Mod. Based on the findings from the present study, and with the inclusion of the newly embedded correction factor, My Jump Lab can now be used as both a valid and reliable means of measuring time to take-off and RSI_Mod in the CMJ

Reactive strength index and its associations with measures of physical and sports performance: a systematic review with meta-analysis

Reactive strength index (RSI) is used frequently in the testing and monitoring of athletes. Associations with sports performance measures may vary dependent on the task but a literature synthesis has not been performed. The aim of this meta-analysis was to examine associations between RSI measured during rebound jumping tasks and measures of strength, linear and change of direction speed, and endurance performance. A systematic literature search with meta-analysis was conducted using databases PubMed, SPORTDiscus, Web of Science, and Ovid. Inclusion criteria required studies to (1) examine the relationship between RSI and an independent measure of physical or sporting performance for at least one variable; and (2) provide rebound test instructions to minimise ground contact time and maximise displacement of the jump. Methodological quality was assessed using a modified version of the Downs and Black Quality Index tool. Heterogeneity was examined via the Q statistic and I . Pooled effect sizes were calculated using a random-effects model, with Egger's regression test used to assess small study bias (inclusive of publication bias). Of the 1320 citations reviewed, a total of 32 studies were included in this meta-analysis. RSI was significantly and moderately associated with strength (isometric: r = 0.356 [95% CI 0.209-0.504]; isotonic: r = 0.365 [0.075-0.654]; pooled strength measures: r = 0.339 [0.209-0.469]) and endurance performance (r = 0.401 [0.173-0.629]). Significant moderate and negative associations were indicated for acceleration (r = - 0.426 [- 0.562 to - 0.290]), top speed (r = - 0.326 [- 0.502 to - 0.151]), and significant large negative associations were noted for change of direction speed (r = - 0.565 [- 0.726 to - 0.404]). Heterogeneity was trivial to moderate across all measures (I  = 0-66%), and significant for isotonic strength and change of direction speed (p < 0.1). Evidence of small study bias was apparent for both acceleration and change of direction speed (p < 0.05). We identified primarily moderate associations between RSI and independent measures of physical and sporting performance, and the strength of these relationships varied based on the task and physical quality assessed. The findings from this meta-analysis can help practitioners to develop more targeted testing and monitoring processes. Future research may wish to examine if associations are stronger in tasks that display greater specificity. [Abstract copyright: © 2021. The Author(s), under exclusive licence to Springer Nature Switzerland AG.

The acute effects of heavy sled towing on subsequent sprint acceleration performance

Objectives: The purpose of this study was to assess the practical use of heavy sled towing and its acute implications on subsequent sprint acceleration performance. Design and Methods: Eight healthy male varsity team sport athletes (age: 21.8±1.8years, height: 185.5±5.0cm, weight: 88.8±15.7kg, 15m sprint time: 2.66±0.13s) performed sprints under three separate weighted sled towing conditions in a randomized order. Each condition consisted of one baseline unweighted sprint (4-min pre), the sled towing sprint protocol: (1) 1x50% body mass, (2) 2x50% body mass, (3) 3x50% body mass (multiple sprints interspersed with 90s recovery), and 3 post-testing unweighted sprints thereafter (4, 8, 12-min post). All sprints were conducted over a 15m distance. Results: Significantly faster sprint times for the 3x sled towing protocol were identified following 8-min of rest (p=0.025, d=0.46, 2.64±0.15s to 2.57±0.17s). When individual best sprint times were analyzed against baseline data, significantly faster sprint times were identified following both 1x (p=0.007, d=0.69, 2.69±0.07s to 2.64±0.07s) and 3x (p=0.001, d=0.62, 2.64±0.15s to 2.55±0.14s) sled towing protocols. Within the 3x condition, all athletes achieved fastest sprint times following 8–12 min of rest. Conclusions: The findings from the present study indicate that a repeated bout of sled towing (3x50% body mass) leads to the enhancement in subsequent sprint acceleration performance, following adequate, and individualized recovery periods

Using the split squat to potentiate bilateral and unilateral jump performance

The purpose of this study was to examine if a split squat conditioning exercise with no or light loads could potentiate unilateral and bilateral jump performance. Twelve semi-professional rugby players (age: 22.3 +/- 1.4 years; height: 1.84 +/- 0.05 m, mass: 92.4 +/- 9.6 kg) from the English National League 1 performed a series of unilateral and bilateral countermovement jumps (CMJ) and broad jumps (BJ) over the course of two testing days. Both testing days involved performing baseline jumps before completing two sets of ten repetitions of a split squat, this completed with either bodyweight (testing session 1) or a 30kg weighted vest (testing session 2). A five-minute recovery period was permitted both following the warm up and following the completion of the split squat exercise. Significantly larger bilateral jump scores were reported following completion of the bodyweight split squat: CMJ (p = 0.001, ES = 0.44, [mean difference 2.517]), BJ (p = 0.001, ES = 0.37, [mean difference 3.817]), and the weighted vest split squat; CMJ (p = 0.001, ES = 0.8, [mean difference 4.383]), BJ (p = 0.001, ES = 0.68, [mean difference 6.817]). The findings of this study demonstrate that no or light loads of a split squat conditioning exercise are able to potentiate bilateral jump performance in semi-professional rugby players without the need for expensive weight room equipment. As such, this may provide coaches with a viable option of enhancing bilateral jump performance as part of a warm up or on-field conditioning practice