2,077 research outputs found

    The effects of a four week primary and secondary speed training protocol on 40 yard sprint times in female college soccer players

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    Improvements in running speed have been attributed to both primary and secondary speed training techniques. Primary techniques involve attention to running mechanics and form, and secondary techniques involve resisted or assisted sprinting. The purpose of this study was to assess the effect of combining both primary and secondary speed training techniques on 40 yard sprint speed in young soccer players. To compare the effects of pre- and post- four week speed training protocol on 40-yard sprint times in female collegiate soccer players. Twelve (19.5+1.5y) normal weight (BMI: 22.7+3.4 kg·m-2) and body composition (BF: 27.75+3.8%) active white female collegiate soccer players participated in a four week training protocol which implemented primary and secondary speed training methods. A standard running mechanics program was implemented two times per week and was immediately followed by resisted or assisted sprinting. Sled towing was chosen for resisted sprinting, while elastic towing devices were chosen for assisted sprinting. Forty yard sprint times were assessed pre and post protocol. Statistical analysis was conducted using SPSS. A paired samples t-test showed the four week speed training protocol elicited statistically significant reductions in 40 yard sprint times (p<0.001). The average sprint time decreased by 0.248 seconds (pre=5.463+0.066 vs post=5.215+0.053). A four week speed training protocol of primary and secondary techniques may play a significant role in reducing 40 yard sprint times in college female soccer athletes. Values are presented as (mean+SEM)

    Tuning localized plasmons in nanostructured substrates for surface-enhanced Raman scattering

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    Comprehensive reflectivity mapping of the angular dispersion of nanostructured arrays comprising of inverted pyramidal pits is demonstrated. By comparing equivalently structured dielectric and metallic arrays, diffraction and plasmonic features are readily distinguished. While the diffraction features match expected theory, localised plasmons are also observed with severely flattened energy dispersions. Using pit arrays with identical pitch, but graded pit dimensions, energy scaling of the localised plasmon is observed. These localised plasmons are found to match a simple model which confines surface plasmons onto the pit sidewalls thus allowing an intuitive picture of the plasmons to be developed. This model agrees well with a 2D finite-difference time-domain simulation which shows the same dependence on pit dimensions. We believe these tuneable plasmons are responsible for the surface-enhancement of the Raman scattering (SERS) of an attached layer of benzenethiol molecules. Such SERS substrates have a wide range of applications both in security, chemical identification, environmental monitoring and healthcare

    Understanding the influence of parent-clinician communication on antibiotic prescribing for children with respiratory tract infections in primary care: a qualitative observational study using a conversation analysis approach

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    Background: Acute respiratory tract infections (RTI) in children are a common reason for antibiotic prescribing. Clinicians’ prescribing decisions are influenced by perceived parental expectations for antibiotics, however there is evidence that parents actually prefer to avoid antibiotics. This study aimed to investigate the influence of parent-clinician communication on antibiotic prescribing for RTI in children in England.Methods: A mixed methods analysis of videoed primary care consultations for children (under 12 years) with acute cough and RTI. Consultations were video-recorded in six general practices in southern England, selected for socio-economic diversity. 56 recordings were transcribed in detail and a subset of recordings and transcripts used to develop a comprehensive interaction-based coding scheme. The scheme was used to examine communication practices between parents and clinicians and how these related to antibiotic or non-antibiotic treatment strategies.Results: Parents’ communication rarely implied an expectation for antibiotics, some explicitly offering a possible viral diagnosis. Clinicians mostly gave, or implied, a viral diagnosis and mainly recommended non-antibiotic treatment strategies. In the minority of cases where parents’ communication behaviours implied they may be seeking antibiotic treatment, antibiotics were not usually prescribed. Where clinicians did prescribe antibiotics, they voiced concern about symptoms or signs, including chest pain, discoloured phlegm, prolonged fever, abnormal chest sounds, or pink /bulging ear drums.Conclusions: We found little evidence of a relationship between parents’ communication behaviours and antibiotic prescribing. Rather, where antibiotics were prescribed, this was associated with clinicians’ expressed concerns regarding symptoms and signs

    Rotation of planet-harbouring stars

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    The rotation rate of a star has important implications for the detectability, characterisation and stability of any planets that may be orbiting it. This chapter gives a brief overview of stellar rotation before describing the methods used to measure the rotation periods of planet host stars, the factors affecting the evolution of a star's rotation rate, stellar age estimates based on rotation, and an overview of the observed trends in the rotation properties of stars with planets.Comment: 16 pages, 4 figures: Invited review to appear in 'Handbook of Exoplanets', Springer Reference Works, edited by Hans J. Deeg and Juan Antonio Belmont

    Fractionation of sulfide phases controls the chalcophile metal budget of arc magmas: evidence from the Chilas complex, Kohistan arc, Pakistan

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    Some arc magmas lead to the formation of porphyry deposits in the relatively shallow upper crust (<5 km). Porphyry deposits are major sources of Cu and an important Au source but lack significant amounts of platinum group elements (PGE). Sulfide phases control the behavior of chalcophile elements and affect the potential to form ore deposits either by remaining in the mantle residue or by fractionating from arc magmas at lower crustal levels, although in detail the role of sulfide saturation in the lower crust remains poorly understood. Lower crustal cumulate rocks from the 85 Ma Chilas Complex of the Kohistan arc, Pakistan, provide insight into processes that occur at depth in arcs. Here we provide Cu, Ni, Au, and PGE concentrations and Os isotope ratios of the Chilas Complex in order to constrain the extent of sulfide saturation in the lower crust and the effect of sulfide saturation on the metal budget of evolved melts that ascend to the upper crust. The Chilas rock suite contains less than 0.17 wt % sulfides and low PGE concentrations. In situ laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) measurements of the sulfide inclusions in silicate minerals show enrichment in several chalcophile elements (up to 34 wt % Cu, 23 ppm Au, 245 ppm Pd, and 20 ppm Pt), whereas iridium group PGE (IPGE- Os, Ir, Ru) are mainly below detection limits. The metal content of the parental melt was modeled based on the elemental concentrations of the sulfides. The modeled parental arc magmas contain 70 to 140 ppm Cu, 0.2 to 1.5 ppb Au, and 1.2 to 8 ppb Pd, but low concentrations of IPGE, suggesting that IPGE were likely retained in the mantle source. Mass balance calculations show that segregation of a sulfide melt in the lower crust could further deplete the melt by more than 95% in Pd and Pt, 33 to 85% in Au, and 13 to 60% in Cu. Thus, magmas that ascend to the upper crust would contain very low concentrations of Au (< 0.2 ppb) and Pd (< 0.04 ppb), but they would retain sufficient concentration of Cu (~45–57 ppm) to form porphyry Cu deposits upon emplacement in the upper crust, as is commonly observed in arc settings

    Diel activity patterns of two distinct populations of Aedes aegypti in Miami, FL and Brownsville, TX

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    The diel biting activity of Aedes (Stegomyia) aegypti (L) populations was extensively investigated in the early 1900s to gain more information on the biology of Ae. aegypti, and this information was used to devise effective approaches to controlling populations of this species and protect the human population from widespread arbovirus outbreaks. However, few contemporary studies are available regarding the diel activity patterns of Ae. aegypti. To assess the diel activity patterns of Ae. aegypti in southern Florida and Texas, we conducted 96-h uninterrupted mosquito collections once each month from May through November 2019 in Miami, Florida, and Brownsville, Texas, using BG-Sentinel 2 Traps. The overall diel activity pattern in both cities was bimodal with morning and evening peak activity between 7:00 and 8:00 and between 19:00 and 20:00. There were significant daily, monthly, seasonal, and site-specific differences in activity patterns, but these differences did not affect the overall peak activity times. These differences suggest daily, monthly, seasonal, and site-specific variations in human exposure to Ae. aegypti. Our observations can be used in planning and executing Ae. aegypti vector control activities in southern Florida and southern Texas, specifically those targeting the adult mosquito populations
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