1,261 research outputs found

    Source energy spectra from demodulation of solar particle data by interplanetary and coronal transport

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    The data on source energy spectra of solar cosmic rays (SCR), i.e. the data on the spectrum form and on the absolute SCR are of interest for three reasons: (1) the SCR contain the energy comparable to the total energy of electromagnetic flare radiation (less than or equal to 10 to the 32nd power ergs); (2) the source spectrum form indicates a possible acceleration mechanism (or mechanism); and (3) the accelerated particles are efficiently involved in nuclear electromagnetic and plasma processes in the solar atmosphere. Therefore, the data on SCR source spectra are necessary for a theoretical description of the processes mentioned and for the formulation of the consistent flare model. Below it is attempted to sound solar particle sources by means of SCR energy spectrum obtained near the Sun, at the level of the roots of the interplanetary field lines in the upper solar corona. Data from approx. 60 solar proton events (SPE) between 1956-1981. These data were obtained mainly by the interplanetary demodulation of observed fluxes near the Earth. Further, a model of coronal azimuthal transport is used to demodulate those spectra, and to obtain the source energy spectra

    Chiral Symmetry Breaking and Confinement Beyond Rainbow-Ladder Truncation

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    A non-perturbative construction of the 3-point fermion-boson vertex which obeys its Ward-Takahashi or Slavnov-Taylor identity, ensures the massless fermion and boson propagators transform according to their local gauge covariance relations, reproduces perturbation theory in the weak coupling regime and provides a gauge independent description for dynamical chiral symmetry breaking (DCSB) and confinement has been a long-standing goal in physically relevant gauge theories such as quantum electrodynamics (QED) and quantum chromodynamics (QCD). In this paper, we demonstrate that the same simple and practical form of the vertex can achieve these objectives not only in 4-dimensional quenched QED (qQED4) but also in its 3-dimensional counterpart (qQED3). Employing this convenient form of the vertex \emph{ansatz} into the Schwinger-Dyson equation (SDE) for the fermion propagator, we observe that it renders the critical coupling in qQED4 markedly gauge independent in contrast with the bare vertex and improves on the well-known Curtis-Pennington construction. Furthermore, our proposal yields gauge independent order parameters for confinement and DCSB in qQED3.Comment: 8 pages, 6 figure

    Examining the Reliability, Validity and Factor Structure of the DRS-15 with College Athletes

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    Hardiness, comprising feelings of commitment, control and challenge, is most frequently measured with the Dispositional Resiliency Scale (DRS), but little work has been done with the brief 15-item version. To examine the factor structure, reliability, validity, and item functioning for gender invariance of the 15-item DRS with 525 collegiate athletes from a wide range of sports. Convergent and divergent validity were examined through relationships with mental toughness, grit and competitive anxiety. Participants completed measures of mental toughness, optimism, grit, competitive anxiety, and the DRS-15. Confirmatory Factor Analysis revealed a poor fit for the three-factor hardiness model, and subsequent exploratory factor analysis yielded a four-factor model with better fit than the three-factor structure. Additionally, several items appear to be biased towards males or females. The fourth factor may be unique to the collegiate athlete population, and related to perceived lack of control in future life directions. Convergent and divergent validity were supported through correlations of DRS scores with related measures. The four-factor model should be tested with different samples to determine if these changes should be adapted when using the DRS-15 in collegiate athletics or other settings

    A Pilot Study Investigating the Reasons for Playing Through Pain and Injury: Emerging Themes in Men’s and Women’s Collegiate Rugby

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    Collegiate rugby is a competitive, collision sport, yet insufficient empirical evidence exists regarding participants’ perspectives on pain and injury. This study addressed male and female rugby players’ experiences with injury, and their views about playing through pain and injury. Eleven rugby players (five male; six female) competing in USA Rugby’s National College 7’s tournament participated in semi structured interviews, which were recorded, transcribed, and content-analyzed. Two major themes emerged: passion for sport and sport ethic. Passion for sport was composed of (a) love of the sport, (b) meaning of the sport, and (c) desire to be on the field. Sport ethic included: (a) helping the team, (b) game time sacrifice, (c) personality, (d) minimize, and (e) accepted behavior. The researchers explain these findings and propose strategies for increasing future athletes’ understanding of the dangers associated with playing through pain, and confronting the currently accepted culture of risk

    Investigating ground-motion duration effects on building portfolio loss estimates

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    Earthquake-induced ground-motion duration can be an important factor to consider when assessing ground-motion damage potential, as evidenced by recent earthquake events worldwide. In current practice, duration is commonly relegated to implicit, qualitative considerations. This study introduces a framework to explicitly quantify the influence of duration on building portfolio direct economic losses. To this end, a simulation-based probabilistic risk modelling framework is developed for different synthetic building portfolios impacted by a case-study seismic source. Two building typologies, representative of distinct vulnerability classes in southern Europe, are considered. A simulation-based probabilistic seismic hazard analysis is performed, explicitly simulating duration jointly with spectral-shape-related intensity measures. Sets of long and one-to-one spectrally-equivalent short duration ground-motion records are selected and then used jointly to perform nonlinear dynamic analysis and derive fragility models for each considered building typology. Fragility relationships are derived by using average spectral acceleration as the primary intensity measure and: 1) maximum inter-storey drift ratio as a demand parameter, indirectly accounting for ground-motion duration (through the adopted nonlinear modelling strategy); 2) maximum inter-storey drift ratio as demand parameter, explicitly considering duration as an intensity measure together with spectral shape, in a vector-valued format. For each case, vulnerability models are developed by combining the fragility relationships with a building-level damage-to-loss model. The portfolio expected annual losses estimated using the described vulnerability models are critically compared and discussed. Depending on the location/portfolio, the impact of ground-motion duration can be significant, and the proposed approaches allow an analyst to account for it in a practical way

    Call repertoire and inferred ecotype presence of killer whales (\u3ci\u3eOrcinus orca\u3c/i\u3e) recorded in the southeastern Chukchi Sea

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    Killer whales occur in the Arctic but few data exist regarding the ecotypes present. The calling behavior differs among ecotypes, which can be distinguished based on pulsed call type, call rate, and bandwidth. In this study, a passive acoustic recorder was deployed 75 km off Point Hope, Alaska, in the southeastern Chukchi Sea to identify which ecotypes were present. A total of 1323 killer whale pulsed calls were detected on 38 of 276 days during the summers (June–August) of 2013–2015. The majority of calls (n = 804, 61%) were recorded in 2013 with the most calls recorded in July (76% of total calls). The calls were manually grouped into six categories: multipart, downsweep, upsweep, modulated, single modulation, and flat. Most detections were flat (n = 485, 37%) or multipart calls (n = 479, 36%), which contained both high and low frequency components. Call comparisons with those reported in the published literature showed similarities with other transient populations in fundamental frequency contour point distribution and median frequency. This study provides the first comprehensive catalog of transient killer whale calls in this region as well as reports on previously undescribed calls

    Detection of high-risk human papillomavirus RNA in urine for cervical cancer screening with HPV 16 & 18/45 genotyping

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    © 2020 The Authors Objective: To detect high-risk human papillomavirus (hrHPV) messenger-RNA (mRNA) in urine samples, compare their concordance with cervical samples including HPV 16 & 18/45 genotyping, and to determine the utility in detecting ≥ CIN 2 lesions. Methods: A cohort of 189 non-pregnant patients (age ≥ 25) was recruited in three groups: Group 1 with abnormal pap-smears and hrHPV positivity, Group 2 with normal pap-smears and hrHPV positivity, and Group 3 with normal pap-smears and hrHPV negativity. Urine samples were tested for hrHPV-mRNA and subsequent hrHPV-mRNA genotype if positive. High-risk HPV detection and genotyping were performed using Aptima assays which are validated for cervical HPV testing. Colposcopy results from groups 1 & 2 were analyzed. Results: The sensitivity of urine hrHPV-mRNA detection was 31.5% while the specificity and PPV were above 95% (96.9% & 95.1% respectively) (p \u3c 0.001). The kappa agreement with cervical samples was fair (0.22, p = 0.04). The sensitivity and specificity of urine hrHPV-mRNA genotyping were 20.0% & 100% respectively (p \u3c 0.001) with 100% genotype-specific concordance. The kappa agreement with cervical samples was fair (0.25, p = 0.16). For urine hrHPV-mRNA detection of ASC-H/HSIL when grouped by age ≥ 30, the sensitivity and specificity were 45.4% & 63.9% respectively (p = 0.009). For urine hrHPV-mRNA detection of ≥ CIN 2 for all ages, the sensitivity and specificity were 45.5% & 75.0% respectively (p = 0.03). Conclusion: Using the Aptima Assay, urine hrHPV-mRNA detection is suboptimal for cervical cancer screening but given the high specificity, it has the potential to identify high-grade lesions (≥ CIN 2). Urine hrHPV-mRNA genotyping via this modality is not beneficial in triage settings of normal or abnormal cytology to determine the need for colposcopy

    High resolution HLA-A, -B, -C and -DRB1 allele and haplotype frequencies in the Costa Rica Central Valley population

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    The Costa Rica Central Valley population (CCVP) is the major population in this country, accounting for over 60% of the Costa Rican inhabitants concentrated since colonial times in a 2,500 km2 intermontane region. Interesting historic, demographic and genetic characteristics of this hybrid population have attracted researchers interested in testing genetic associations for various diseases. However, no study describing Human Leukocyte Antigen (HLA) frequencies by molecular methods had been performed. We have recently described low resolution HLA allele group and haplotype frequencies in a sample of this population. In this report, we extend our study to high resolution by sequence-based typing of exons 2, 3 and 4 for class I, and exon 2 for HLA-DRB1. DNA was extracted from blood or saliva samples from a cohort of 205 non-related healthy donors recruited as part of the University of Costa Rica’s Centre for Research in Hematology and Related Disorders (CIHATA) DNA bank. All participants were born in the CCVP and gave informed consent. A total of 37 HLA-A, 61 HLA-B, 24 HLA-C and 38 HLA-DRB1 alleles were seen in this sample. The five most frequent alleles for these genes are HLA-A*02:01:01, HLA-A*24:02:01, HLA-A*03:01:01, HLA-A*01:01:01, HLA-A*68:01:02, HLA-B*07:02:01, HLA-B*40:02:01, HLA-B*35:01:01, HLA-B*44:02:01, HLA-B*14:02:01, HLA-C*04:01:01, HLA-C*07:02:01, HLA-C*03:05, HLA-C*06:02:01, HLA-C*07:01:01, HLA-DRB1*13:01:01G, HLA-DRB1*04:07:01G, HLA-DRB1*15:01:01G, HLA-DRB1*03:01:01G, and HLA-DRB1*07:01:01G. Preliminary haplotype estimation results show, as a proxy for admixture proportions, that 68% of the extended haplotypes are Caucasian, while 23% are Amerindian in origin and 9% are clearly Sub-Saharan African. Principal coordinates analysis based on HLA-A and –B allele group frequencies reveals that this population clusters among other admixed groups with strong Caucasian component that lie closely to Iberian populations

    Psychological Responses of Division I Female Athletes Throughout Injury Recovery: A Case Study Approach

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    Abstract: Using the Integrated Model of Response to Sport Injury as a theoretical framework, athletes' psychological strengths and emotional responses were explored throughout the injury process using a case study approach. Four Division I athletes completed measures of mental toughness, hardiness, and optimism before their season (time 1), once they became injured (time 2), midway through rehabilitation (time 3), and when they were cleared to participate (time 4). Coping behavior, psychological response, and rehabilitation adherence were recorded at time 2-time 4, while recovering. In addition, interviews were conducted after time 4. Mental toughness, hardiness, and optimism varied over time and across cases, with broad individual differences in response to injury. Athletes experienced a loss of athletic identity combined with feelings of guilt and helplessness over the initial stages of injury, but positive experiences were also found. All cases also reported playing through injury. Understanding the psychological strengths and responses of athletes can help professionals work with injured athletes. Keywords: athletes | injury | Integrated Model of Response to Sport Injury | case study Article: Each year sports-related injuries to children and young adults result in nearly three million emergency room visits, 30,000 hospitalizations, and billions of dollars in healthcare expenditure

    FORTY YEARS OF BEHAVIOR ANALYSIS IN MEXICO: A REVIEW OF THE MEXICAN JOURNAL OF BEHAVIOR ANALYSIS

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    The present paper shows a current review of the Mexican Journal of Behavior Analysis (MJBA). The review includes a brief historical summary of the Mexican Society of Behavior Analysis, along with some aspects about the academic and social context of behavior analysis in Mexico which are mentioned in order to understand the origin of MJBA. The paper presents the number of articles published in English and Spanish, an analysis of the articles related to human and non-human behavior, basic and applied research. The paper also reports the first authors’ university affiliation with higher percentage of articles published.Keywords: behavior analysis in Mexico, Mexican Journal of Behavior Analysis, Mexican Society of Behavior Analysi
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