1,623 research outputs found
The Benefits of a Challenge Approach on Match Day: Investigating Cardiovascular Reactivity in Professional Academy Soccer Players.
This study assessed physiological (cardiovascular) and psychological (confidence, control, and approach focus) data in professional academy soccer players prior to performance in competitive matches. A challenge state is characterised by an increase in cardiac output (CO), and a decrease in total peripheral vascular resistance (TPR). Data were collected from 37 participants, with 19 of these providing data on two separate occasions. Performance was measured using coach and player self-ratings. Challenge reactivity was positively, and significantly, associated with performance. Participants who demonstrated blunted cardiovascular (CV) responses performed significantly worse than participants who displayed either challenge or threat reactivity. There was mixed consistency in CV reactivity for those participants whose data were collected on more than one occasion, suggesting that some participants responded differently across the competitive matches. The association between self-report data and CV responses was weak. This study supports previous research demonstrating that challenge reactivity is associated with superior performance
The non-Abelian gauge theory of matrix big bangs
We study at the classical and quantum mechanical level the time-dependent
Yang-Mills theory that one obtains via the generalisation of discrete
light-cone quantisation to singular homogeneous plane waves. The non-Abelian
nature of this theory is known to be important for physics near the
singularity, at least as far as the number of degrees of freedom is concerned.
We will show that the quartic interaction is always subleading as one
approaches the singularity and that close enough to t=0 the evolution is driven
by the diverging tachyonic mass term. The evolution towards asymptotically flat
space-time also reveals some surprising features.Comment: 29 pages, 8 eps figures, v2: minor changes, references added: v3
small typographical changes
Extremely high He isotope ratios in MORB-source mantle from the proto-Iceland plume
The high <sup>3</sup>He/<sup>4</sup>He ratio of volcanic rocks thought to be derived from mantle plumes is taken as evidence for the existence of a mantle reservoir that has remained largely undegassed since the Earth's accretion. The helium isotope composition of this reservoir places constraints on the origin of volatiles within the Earth and on the evolution and structure of the Earth's mantle. Here we show that olivine phenocrysts in picritic basalts presumably derived from the proto-Iceland plume at Baffin Island, Canada, have the highest magmatic <sup>3</sup>He/<sup>4</sup>He ratios yet recorded. A strong correlation between <sup>3</sup>He/<sup>4</sup>He and <sup>87</sup>Sr/<sup>86</sup>Sr, <sup>143</sup>Nd/<sup>144</sup>Nd and trace element ratios demonstrate that the <sup>3</sup>He-rich end-member is present in basalts that are derived from large-volume melts of depleted upper-mantle rocks. This reservoir is consistent with the recharging of depleted upper-mantle rocks by small volumes of primordial volatile-rich lower-mantle material at a thermal boundary layer between convectively isolated reservoirs. The highest <sup>3</sup>He/<sup>4</sup>He basalts from Hawaii and Iceland plot on the observed mixing trend. This indicates that a <sup>3</sup>He-recharged depleted mantle (HRDM) reservoir may be the principal source of high <sup>3</sup>He/<sup>4</sup>He in mantle plumes, and may explain why the helium concentration of the 'plume' component in ocean island basalts is lower than that predicted for a two-layer, steady-state model of mantle structure
Surgical Treatment of Iatrogenic Ventral Glottic Stenosis Using a Mucosal Flap Technique
OBJECTIVE: To describe a novel surgical technique for correcting postoperative ventral glottic stenosis (cicatrix or web formation) and the outcome in 2 Thoroughbred racehorses. STUDY DESIGN: Retrospective case report. ANIMALS: Thoroughbreds diagnosed with ventral glottic stenosis (n=2). METHODS: Horses presenting with iatrogenic ventral glottic stenosis and resultant exercise intolerance and abnormal exerciseârelated noise were anesthetized and a midline sagittal skin incision was made over the ventral larynx and between the sternohyoideus muscles overlying the cricothyroid notch. The cricothyroid ligament, attached laryngeal cicatrix, and overlying mucosa were sagittally sectioned at the dorsal aspect of the cicatrix on the left side. The laryngeal mucosa, cicatrix, and underlying cricothyroid ligament immediately rostral and caudal to the cicatrix were sectioned in a medial (axial) direction as far as the right side of the cricothyroid notch. After resection of the majority of the attached cicatrix tissue, the residual mucosal flap (attached to the right side of the larynx) was reflected ventrally and sutured to the attachment of the cricothyroid ligament on the right side of the cricothyroid notch, creating an intact mucosal layer on the right side of the ventral larynx. RESULTS: Both horses had good intralaryngeal wound healing with minimal redevelopment of ventral glottic stenosis at 5 and 9 months postoperatively and were successfully returned to racing with complete absence of abnormal respiratory noise. CONCLUSION: The unique laryngeal anatomy of horses, with a cartilageâfree ventral laryngeal area (cricothyroid notch), allowed the use of this novel surgical technique to successfully treat ventral glottic stenosis
Amine-modified polyionic liquid supports enhance the efficacy of PdNPs for the catalytic hydrogenation of CO<sub>2</sub> to formate
Ben Lawers: an archaeological landscape in time. Results from the Ben Lawers Historic Landscape Project, 1996â2005
This volume presents the results of archaeological investigations between 1996 and 2005, carried out as part of the Ben Lawers Historic Landscape Project, a multi-disciplinary project based on north Loch Tayside in the Central Highlands of Scotland. Archaeological surveys and excavations formed the core of the Ben Lawers Project, but many other disciplines also contributed to researching this landscape. Some of these partner projects are reported here, while others have been presented elsewhere (Tipping et al 2009), and some have formed part of doctoral research projects (Watters 2007). The results of the 13 field seasons, particularly the nine evaluation and excavation seasons, together with the results of the partner projects, specialist studies and scientific analyses, have provided a body of evidence which permits the story of the land of Lawers to be told. The historical continuum in that story can be used to curate and manage this landscape for generations to come
Ursodeoxycholic acid to reduce adverse perinatal outcomes for intrahepatic cholestasis of pregnancy: the PITCHES RCT
Background:
Intrahepatic cholestasis of pregnancy, characterised by maternal pruritus and raised serum bile acid concentrations, is associated with increased rates of stillbirth, preterm birth and neonatal unit admission. Ursodeoxycholic acid is widely used as a treatment, but without an adequate evidence base. /
Objective:
We aimed to evaluate whether or not ursodeoxycholic acid reduces adverse perinatal outcomes in affected women. /
Design:
Multicentre, masked, randomised, placebo-controlled, two-arm, parallel-group trial. /
Setting:
Thirty-three UK maternity units. /
Participants:
Women with intrahepatic cholestasis of pregnancy aged â„â18 years, between 20+0 and 40+6 weeksâ gestation with a singleton or twin pregnancy and no known lethal fetal anomaly. /
Interventions:
Women were randomly assigned (1â:â1 allocation ratio) to take ursodeoxycholic acid tablets or matched placebo tablets, at an equivalent dose of 1000âmg daily, titrated as needed. /
Main outcome measures:
The primary outcome was a composite of perinatal death (in utero fetal death after randomisation or known neonatal death up to 7 days) or preterm delivery (<â37 weeksâ gestation) or neonatal unit admission for at least 4 hours (from birth until hospital discharge). Each infant was counted once within this composite. Analyses were by intention to treat. /
Results:
Between 23 December 2015 and 7 August 2018, 605 women were randomised, with 305 women allocated to the ursodeoxycholic acid arm and 300 women to the placebo arm. There was no evidence of a significant difference in the incidence of the primary outcome between the groups: 23.0% (74 out of 322 infants) in the ursodeoxycholic acid group compared with 26.7% (85 out of 318 infants) in the placebo group; adjusted risk ratio 0.85 (95% confidence interval 0.62 to 1.15). There was no evidence of a significant difference in total costs (maternal, infant and the cost of ursodeoxycholic acid) between the two trial groups. There were two serious adverse events in the ursodeoxycholic acid group and six in the placebo group. /
Limitations:
Limitations include a primary outcome event rate in the control group that was lower than that estimated for the sample size calculation, but the lack of evidence of effect in all analyses suggests that it is unlikely that the trial had insufficient power. /
Conclusions:
In this clinical trial of ursodeoxycholic acid in women with intrahepatic cholestasis of pregnancy, there is no evidence that it is effective in reducing a composite of adverse perinatal outcomes. /
Future work:
Future research should aim to elucidate the aetiology and pathophysiology of adverse perinatal outcomes, particularly stillbirth, in women with intrahepatic cholestasis of pregnancy to assist the development of an effective preventative treatment. Further exploratory analyses may identify groups of women who might respond to ursodeoxycholic acid treatment. /
Trial registration:
Current Controlled Trials ISRCTN91918806. /
Funding:
This project was funded by the Efficacy and Mechanism Evaluation (EME) Programme, a Medical Research Council and National Institute for Health Research (NIHR) partnership. This will be published in full in Efficacy and Mechanism Evaluation; Vol. 7, No. 9. See the NIHR Journals Library website for further project information
Development of a taxonomy to describe massage treatments for musculoskeletal pain
BACKGROUND: One of the challenges in conducting research in the field of massage and bodywork is the lack of consistent terminology for describing the treatments given by massage therapists. The objective of this study was to develop a taxonomy to describe what massage therapists actually do when giving a massage to patients with musculoskeletal pain. METHODS: After conducting a review of the massage treatment literature for musculoskeletal pain, a list of candidate techniques was generated for possible inclusion in the taxonomy. This list was modified after discussions with a senior massage therapist educator and seven experienced massage therapists participating in a study of massage for neck pain. RESULTS: The taxonomy was conceptualized as a three level classification system, principal goals of treatment, styles, and techniques. Four categories described the principal goal of treatment (i.e., relaxation massage, clinical massage, movement re-education and energy work). Each principal goal of treatment could be met using a number of different styles, with each style consisting of a number of specific techniques. A total of 36 distinct techniques were identified and described, many of which could be included in multiple styles. CONCLUSION: A new classification system is presented whereby practitioners using different styles of massage can describe the techniques they employ using consistent terminology. This system could help facilitate standardized reporting of massage interventions
Topological crystalline insulator states in Pb(1-x)Sn(x)Se
Topological insulators are a novel class of quantum materials in which
time-reversal symmetry, relativistic (spin-orbit) effects and an inverted band
structure result in electronic metallic states on the surfaces of bulk
crystals. These helical states exhibit a Dirac-like energy dispersion across
the bulk bandgap, and they are topologically protected. Recent theoretical
proposals have suggested the existence of topological crystalline insulators, a
novel class of topological insulators in which crystalline symmetry replaces
the role of time-reversal symmetry in topological protection [1,2]. In this
study, we show that the narrow-gap semiconductor Pb(1-x)Sn(x)Se is a
topological crystalline insulator for x=0.23. Temperature-dependent
magnetotransport measurements and angle-resolved photoelectron spectroscopy
demonstrate that the material undergoes a temperature-driven topological phase
transition from a trivial insulator to a topological crystalline insulator.
These experimental findings add a new class to the family of topological
insulators. We expect these results to be the beginning of both a considerable
body of additional research on topological crystalline insulators as well as
detailed studies of topological phase transitions.Comment: v2: published revised manuscript (6 pages, 3 figures) and
supplementary information (5 pages, 8 figures
Probing Behavior of Apterous and Alate Morphs of two PotatoâColonizing Aphids
Secondary host plant colonization by aphids involves alate and apterous morphs to spread in the population at a large scale by flying or, at a finer one, by walking. Macrosiphum euphorbiae Thomas (Hemiptera: Aphididae) and Myzus persicae Sulzer (Hemiptera: Aphididae) are two polyphagous aphids that cause serious losses on many crops, particularly on potato, Solanum tuberosum L. (Solanales: Solanaceae). When settlement of virginoparous alate aphids occurs, apterous individuals are produced and spread within the potato field. As these two potato colonizers originate from different areas and show different body length, this study compared probing behaviors of virginoparous alate and apterous M. persicae and M. euphorbiae on one of their secondary host plants, Solanum tuberosum. Nonâchoice bioassays and electrical penetration graph (EPG) recordings were performed. Most M. euphorbiae of the two morphs rapidly accepted potato plants and exhibited long duration of probing, phloem sap salivation, and ingestion phases. In contrast, at the end of the experiment, most alates of M. persicae left the potato leaflet after brief gustative probes. Moreover, EPG experiments showed that the main difference between both morphs of the two species concerned the xylem ingestion parameter. Differences between species were also reported, such as an increased total duration of probing in both morphs and enhanced phloem ingestion duration in apterous M. euphorbiae. All the differences highlighted in this study are discussed according to the variations observed in aphid body size and to their historical association with Solanum species
- âŠ