738 research outputs found
The US golf academy system and the twenty first century talent tourists! Future lines of research to understand this new golfing talent pathway
This paper addresses the rapid growth, popularity, and structure of US Golf Academies. Specifically, we highlight a phenomenon from a non-US golfing community’s perspective; namely, that of the “talent tourist” (i.e., youth golfer) seeking to develop their playing skills and academic ability within a foreign talent pathway. With so much of these golfers’ futures at stake (e.g., large financial costs and time dedicated), there is a surprising lack of research attention paid to these academies’ talent development environments; for instance, their structure, position in the overall talent pathway, the quality of the approaches used, or reasons why golfers strive to enroll onto them. By addressing these issues, this paper will present the case for greater research interest and the development of more effective talent development pathways
The Origin of Galactic Cosmic Rays
Motivated by recent measurements of the major components of the cosmic
radiation around 10 TeV/nucleon and above, we discuss the phenomenology of a
model in which there are two distinct kinds of cosmic ray accelerators in the
galaxy. Comparison of the spectra of hydrogen and helium up to 100 TeV per
nucleon suggests that these two elements do not have the same spectrum of
magnetic rigidity over this entire region and that these two dominant elements
therefore receive contributions from different sources.Comment: To be published in Physical Review D, 13 pages, with 3 figures,
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Strings in Homogeneous Background Spacetimes
The string equations of motion for some homogeneous (Kantowski-Sachs, Bianchi
I and Bianchi IX) background spacetimes are given, and solved explicitly in
some simple cases. This is motivated by the recent developments in string
cosmology, where it has been shown that, under certain circumstances, such
spacetimes appear as string-vacua.
Both tensile and null strings are considered. Generally, it is much simpler
to solve for the null strings since then we deal with the null geodesic
equations of General Relativity plus some additional constraints.
We consider in detail an ansatz corresponding to circular strings, and we
discuss the possibility of using an elliptic-shape string ansatz in the case of
homogeneous (but anisotropic) backgrounds.Comment: 25 pages, REVTE
Physical symptoms and brain morphology:a population neuroimaging study in 12,286 pre-adolescents
Physical symptoms, also known as somatic symptoms, are those for which medical examinations do not reveal a sufficient underlying root cause (e.g., pain and fatigue). The extant literature of the neurobiological underpinnings of physical symptoms is largely inconsistent and primarily comprises of (clinical) case-control studies with small sample sizes. In this cross-sectional study, we studied the association between dimensionally measured physical symptoms and brain morphology in pre-adolescents from two population-based cohorts; the Generation R Study (n = 2649, 10.1 ± 0.6 years old) and ABCD Study (n = 9637, 9.9 ± 0.6 years old). Physical symptoms were evaluated using continuous scores from the somatic complaints syndrome scale from the parent-reported Child Behavior Checklist (CBCL). High‐resolution structural magnetic resonance imaging (MRI) was collected using 3-Tesla MRI systems. Linear regression models were fitted for global brain metrics (cortical and subcortical grey matter and total white matter volume) and surface-based vertex-wise measures (surface area and cortical thickness). Results were meta-analysed. Symptoms of anxiety/depression were studied as a contrasting comorbidity. In the meta-analyses across cohorts, we found negative associations between physical symptoms and surface area in the (i) left hemisphere; in the lateral orbitofrontal cortex and pars triangularis and (ii) right hemisphere; in the pars triangularis, the pars orbitalis, insula, middle temporal gyrus and caudal anterior cingulate cortex. However, only a subset of regions (left lateral orbitofrontal cortex and right pars triangularis) were specifically associated with physical symptoms, while others were also related to symptoms of anxiety/depression. No significant associations were observed for cortical thickness. This study in preadolescents, the most representative and well-powered to date, showed that more physical symptoms are modestly related to less surface area of the prefrontal cortex mostly. While these effects are subtle, future prospective research is warranted to understand the longitudinal relationship of physical symptoms and brain changes over time. Particularly, to elucidate whether physical symptoms are a potential cause or consequence of distinct neurodevelopmental trajectories.</p
White Matter Microstructure and the General Psychopathology Factor in Children
Objective: Co-occurrence of behavioral and emotional problems in childhood is widespread, and previous studies have suggested that this reflects vulnerability to experience a range of psychiatric problems, often termed a general psychopathology factor. However, the neurobiological substrate of this general factor is not well understood. We tested the hypothesis that lower overall white matter microstructure is associated with higher levels of the general psychopathology factor in children and less with specific factors. Method: Global white matter microstructure at age 10 years was related to general and specific psychopathology factors. These factors were estimated using a latent bifactor model with multiple informants and instruments between ages 6 and 10 years in 3,030 children from the population-based birth cohort Generation R. The association of global white matter microstructure and the psychopathology factors was examined with a structural equation model adjusted for sex, age at scan, age at psychopathology assessment, parental education/income, and genetic ancestry. Results: A 1-SD increase of the global white matter factor was associated with a β = −0.07SD (standard error [SE] = 0.02, p < .01) decrease in general psychopathology. In contrast, a 1-SD increase of white matter microstructure predicted an increase of β = +0.07 SD (SE = 0.03, p < .01) specific externalizing factor levels. No association was found with the specific internalizing and specific attention factor. Conclusion: The results suggest that general psychopathology in childhood is related to white matter structure across the brain and not only to specific tracts. Taking into account general psychopathology may also help reveal neurobiological mechanisms behind specific symptoms that are otherwise obscured by comorbidity
Temporal sensitivity analysis of erosivity estimations in a high rainfall tropical island environment
The Erosivity Index (EI) and the Modified
Fournier Index (MFI) are two commonly used methods in
calculating the R factor of the universal soil loss equation/
revised universal soil loss equation formula. Using Mauritius
as a case study, the value of high-resolution data versus
long-term totals in erosivity calculations is investigated. A
limited number of four Mauritius Meteorological Services
stations located on the west coast and the Central Plateau
provided the study with detailed rainfall data for 6 years at
6-min intervals. Rainfall erosivity for erosive events was
calculated using different set interval data. In this study,
within the EI, the use of 6-min rainfall intervals during
erosive rainfall gave estimates of around 10% more erosivity
than the 30-min time intervals and 33% more rainfall erosivity
than the 60-min rainfall measurements. When the MFI
was used to determine erosivity through annual and monthly
rainfall totals, substantially higher erosivity than the EI
method was calculated in both regions. This stems from the
large amount of non-erosive rainfall that is generated on
Mauritius. Even when the MFI was used to calculate erosivity
through monthly and annual rainfall totals derived purely
from erosive rainfall, erosivity calculations were not comparable
to those from high-resolution data within the EI. We
suggest that for the computation of erosivity, rainfall data
with the highest possible resolution should be utilised if
available and that the application of annual and monthly
rainfall totals to assess absolute soil erosion risk within a
high rainfall tropical environment must be used with caution.http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1468-0459hb201
Monitoring of drinking water quality using automated ATP quantification
A microfluidic based system was developed for automated online method for the rapid detection and monitoring of drinking water contamination utilising microbial Adrenosine-5′-Triphosphate (ATP) as a bacterial indicator. The system comprises a polymethyl methacrylate based microfluidic cartridge inserted into an enclosure incorporating the functions of fluid storage and delivery, lysis steps and real-time detection. Design, integration and operation of the resulting automated system are reported, including the lysis method, the design of the mixing circuit, the choices of flow rate, temperature and reagent amount. Calibration curves of both total and free ATP were demonstrated to be highly linear over a range from 2.5–5000 pg/mL with the limit of detection being lower than 2.5 pg/mL of total ATP. The system was trialled in a lab study with different types of water, with lysis efficiency being found to be strongly dependent upon water type. Further development is required before online implementation
Positive effects of tree diversity on tropical forest restoration in a field-scale experiment
Acknowledgments We thank all SEARPP research assistants and other collaborators for the help in establishing and maintaining the Sabah Biodiversity Experiment. We acknowledge assistance and support from SEARRP, Sabah Forestry Department, and the Leverhulme Trust—the Leverhulme Centre for Nature Recovery (A.H). Sabah Biodiversity Experiment data collection and maintenance was supported by Agencia Estatal de Investigación de España. This is Sabah Biodiversity Experiment publication 25. Funding: This work was supported by Natural Environment Research Council grants NE/S007474/1 (R.V.), NE/K016253/1 (A.H., S.B., D.F.R.P.B., and G.R.), and NE/X000281/1 (A.H. and D.F.R.P.B.); Comunidad de Madrid Atracción de Talento Modalidad I Fellowship 2018-T1/AMB-11095 (MJO); Agencia Estatal de Investigación de España (Ramon y Cajal, RYC2021-032049-I) (MJO); University of Zurich Research Priority Program on Global Change and Biodiversity (B.S.); and National Natural Science Foundation of China grant 42101407 (J.W.).Peer reviewedPublisher PD
NN Core Interactions and Differential Cross Sections from One Gluon Exchange
We derive nonstrange baryon-baryon scattering amplitudes in the
nonrelativistic quark model using the ``quark Born diagram" formalism. This
approach describes the scattering as a single interaction, here the
one-gluon-exchange (OGE) spin-spin term followed by constituent interchange,
with external nonrelativistic baryon wavefunctions attached to the scattering
diagrams to incorporate higher-twist wavefunction effects. The short-range
repulsive core in the NN interaction has previously been attributed to this
spin-spin interaction in the literature; we find that these perturbative
constituent-interchange diagrams do indeed predict repulsive interactions in
all I,S channels of the nucleon-nucleon system, and we compare our results for
the equivalent short-range potentials to the core potentials found by other
authors using nonperturbative methods. We also apply our perturbative
techniques to the N and systems: Some
channels are found to have attractive core potentials and may accommodate
``molecular" bound states near threshold. Finally we use our Born formalism to
calculate the NN differential cross section, which we compare with experimental
results for unpolarised proton-proton elastic scattering. We find that several
familiar features of the experimental differential cross section are reproduced
by our Born-order result.Comment: 27 pages, figures available from the authors, revtex, CEBAF-TH-93-04,
MIT-CTP-2187, ORNL-CCIP-93-0
KASCADE measurements of energy spectra for elemental groups of cosmic rays: Results and open problems
A composition analysis of KASCADE air shower data is performed by means of
unfolding the two-dimensional frequency spectrum of electron and muon numbers.
Aim of the analysis is the determination of energy spectra for elemental groups
representing the chemical composition of primary cosmic rays. Since such an
analysis depends crucially on simulations of air showers the two different
hadronic interaction models QGSJet and SIBYLL are used for their generation.
The resulting primary energy spectra show that the knee in the all particle
spectrum is due to a steepening of the spectra of light elements but, also,
that neither of the two simulation sets is able to describe the measured data
consistently over the whole energy range with discrepancies appearing in
different energy regions.Comment: 39 pages, accepted for publication in Astropart. Phy
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