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1.
Heliyon ; 10(2): e24359, 2024 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-38293548

RESUMO

The current study aimed to create a reliable and valid scale to measure athletes' perception of fairness regarding coaches' behaviors. The study utilized a scale development process, including three steps: (a) item generation, (b) scale development, and (c) scale evaluation. Both quantitative and qualitative approaches were utilized to generate items and achieve content validity. In developing the AJ scale, elite athletes from 29 different sports in Saudi Arabia were recruited for two rounds of data collection. The first data set (n = 279) was collected using an initial 35-item AJ scale developed from existing justice scales and interviews with elite athletes, while the second data collection (n = 503) was performed using a refined 12-item scale based on the analysis of the first data set. The results of ESEM showed an appropriate model fit for the scale with 12 items including four dimensions. In addition, the criterion validity was supported as each dimension of AJ was positively associated with athlete satisfaction. The newly developed AJ scale will help researchers measure perceived fairness toward coaches' behaviors based on the unique culture, climate, and environment that exists in the context of sports and explore the relationships between AJ and important attitudinal and behavioral outcomes that impact team performance.

2.
Behav Sci (Basel) ; 13(10)2023 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-37887486

RESUMO

Athletes' perceptions of fairness toward coaching behaviors and decisions can play a crucial role in the development and maintenance of a strong coach-athlete relationship. However, scholars have given limited attention to athletes' perceptions of fairness. Therefore, the current study aimed to explore the relationship between coaches and athletes by applying the concept of organizational justice based on met-expectation theory. The primary objective of the study was to empirically examine the direct and indirect relationships between the met-expectation of athletic justice and athletes' attitudinal outcomes, such as athletic satisfaction and organizational commitment, through leader-member exchange (LMX). Data were collected from 289 elite athletes (238 men and 51 women) in the Kingdom of Saudi Arabia using a mixed-mode approach (paper-and-pencil and online surveys). The results of Structural Equation Modeling indicated that when athletes perceive that their expectations of fair treatment are met, it positively affects their satisfaction. This relationship is partially influenced by the quality of their relationship with their leader. However, the findings also suggest that while the athletes' met-expectation of athletic justice has a positive effect on their satisfaction, it does not have a significant impact on their commitment to the team. The findings provide insight about important work-related outcomes by validating the coach-athlete relationship based on met-expectation of athletic justice. The findings can be utilized to improve athlete satisfaction and commitment, leading to positive team and individual outcomes.

4.
Front Psychol ; 13: 1012953, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36578680

RESUMO

Introduction: The current study investigated the impacts of autocratic and democratic leadership styles on the coach-athlete relationship, athletes' motivations, and athlete satisfaction. Methods: Survey data were collected from 298 student-athletes (male = 157; 52.7%, female = 141; 47.3%) from 20 different Chinese collegiate sports. The Structural Equation Model was used to test the hypothesized model. Results: The results indicated democratic leadership had a direct positive influence on the coach-athlete relationship, while autocratic leadership had no direct effect. Both leadership styles did not influence autonomous motivation. The coach-athlete relationship, meanwhile, had a full mediation effect between democratic leadership and athletes' motivation and satisfaction. In addition, autonomous motivation had a partial mediation effect between the coach-athlete relationship and athlete satisfaction. Discussion: Ultimately, the findings of the current study underscore the need for coaches and administrators to understand the impact of different leadership styles and highlight the importance of democratic leadership in improving athletes' psychological outcomes.

5.
Adapt Phys Activ Q ; 33(3): 253-70, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27623609

RESUMO

Adults with Down syndrome (DS) tend to have low physical activity levels, which may relate to how they perceive participation in physical activities. The current study entailed interviews with 30 adults with DS (age 18-71 yr, 18 women) to examine how they perceived physical activity, exercise, and sport. Through qualitative analysis informed by grounded theory, the investigators found that adults with DS have positive perceptions of physical activity that center on enjoyment. Three facets of enjoyment were identified: interaction, achievement, and process. Interaction reflected enjoyment of social contact with others including relatives, peers, caregivers, and animals. Achievement involved enjoyment of achieving particular ends including accomplishment of tasks, material rewards, formation of athletic identities, and improvement of health. Process represented enjoyment from performing a particular activity itself. This multifaceted enjoyment expressed by adults with DS may facilitate physical activity and should be considered when developing programs to improve their well-being.


Assuntos
Síndrome de Down/psicologia , Exercício Físico , Adolescente , Adulto , Idoso , Teoria Fundamentada , Humanos , Entrevistas como Assunto , Pessoa de Meia-Idade , Percepção , Pesquisa Qualitativa
6.
Percept Mot Skills ; 121(2): 371-89, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26474439

RESUMO

The current study examined perceived event prestige as a mediator between sport involvement and sport participation behavioral intent. A total of 455 participants (M age = 28.6 yr., SD = 9.1) were recruited at the 2013 Standard Chartered Hong Kong Marathon. The findings indicated that a model in which perceived event prestige partially mediated the relationship between sport involvement and intent to return to the event was most representative of the data. While individuals with higher sport involvement were more likely to indicate an interest in continued participation, this relationship was strongest among those who perceived the event to be particularly prestigious. Thus, those who market mass participation sporting events should use strategies designed to emphasize the prestigious stature of the event and should employ measures to increase sport involvement among participants.


Assuntos
Comportamento Competitivo , Intenção , Internacionalidade , Motivação , Corrida/psicologia , Desejabilidade Social , Adolescente , Adulto , Feminino , Hong Kong , Humanos , Masculino , Pessoa de Meia-Idade , Psicometria , Inquéritos e Questionários , Adulto Jovem
7.
Biosecur Bioterror ; 10(1): 108-22, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22352747

RESUMO

Decontaminating civilian facilities or large urban areas following an attack with Bacillus anthracis poses daunting challenges because of the lack of resources and proven technologies. Nevertheless, lessons learned from the 2001 cleanups together with advances derived from recent research have improved our understanding of what is required for effective decontamination. This article reviews current decontamination technologies appropriate for use in outdoor environments, on material surfaces, within large enclosed spaces, in water, and on waste contaminated with aerosolized B. anthracis spores.


Assuntos
Antraz/prevenção & controle , Bacillus anthracis , Bioterrorismo/prevenção & controle , Descontaminação/métodos , Antraz/economia , Bioterrorismo/economia , Descontaminação/economia , Descontaminação/instrumentação , Desinfetantes , Órgãos Governamentais/organização & administração , Humanos , Estados Unidos , Gerenciamento de Resíduos
8.
J Hazard Mater ; 196: 115-22, 2011 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-21944706

RESUMO

Bench-scale testing was used to evaluate the efficacy of four decontamination formulations on typical indoor surfaces following exposure to the liquid chemical warfare agents sarin (GB), soman (GD), sulfur mustard (HD), and VX. Residual surface contamination on coupons was periodically measured for up to 24h after applying one of four selected decontamination technologies [0.5% bleach solution with trisodium phosphate, Allen Vanguard Surface Decontamination Foam (SDF™), U.S. military Decon Green™, and Modec Inc. and EnviroFoam Technologies Sandia Decontamination Foam (DF-200)]. All decontamination technologies tested, except for the bleach solution, performed well on nonporous and nonpermeable glass and stainless-steel surfaces. However, chemical agent residual contamination typically remained on porous and permeable surfaces, especially for the more persistent agents, HD and VX. Solvent-based Decon Green™ performed better than aqueous-based bleach or foams on polymeric surfaces, possibly because the solvent is able to penetrate the polymer matrix. Bleach and foams out-performed Decon Green for penetrating the highly polar concrete surface. Results suggest that the different characteristics needed for an ideal and universal decontamination technology may be incompatible in a single formulation and a strategy for decontaminating a complex facility will require a range of technologies.


Assuntos
Clareadores/química , Substâncias para a Guerra Química/análise , Descontaminação/métodos , Poluentes Ambientais/análise , Habitação/normas , Oxirredução , Projetos Piloto , Propriedades de Superfície
9.
Hum Ecol Risk Assess ; 17(1): 57-121, 2011 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-21399674

RESUMO

In the event of a chemical terrorist attack on a transportation hub, post-event remediation and restoration activities necessary to attain unrestricted facility re-use and re-entry could require hours to multiple days. While timeframes are dependent on numerous variables, a primary controlling factor is the level of pre-planning and decision-making completed prior to chemical release. What follows is the second of a two-part analysis identifying key considerations, critical information and decision criteria to facilitate post-attack and post-decontamination consequence management activities. Decision criteria analysis presented here provides first-time, open-literature documentation of multi-pathway, health-based remediation exposure guidelines for selected toxic industrial compounds, chemical warfare agents, and agent degradation products for pre-planning application in anticipation of a chemical terrorist attack. Guideline values are provided for inhalation and direct ocular vapor exposure routes as well as percutaneous vapor, surface contact, and ingestion. Target populations include various employees as well as transit passengers. This work has been performed as a national case study conducted in partnership with the Los Angeles International Airport and The Bradley International Terminal. All recommended guidelines have been selected for consistency with airport scenario release parameters of a one-time, short-duration, finite airborne release from a single source followed by compound-specific decontamination.

10.
Hum Ecol Risk Assess ; 17(1): 2-56, 2011 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-21390292

RESUMO

In the event of a chemical terrorist attack on a transportation hub, post-event remediation and restoration activities necessary to attain unrestricted facility reuse and re-entry could require hours to multiple days. While restoration timeframes are dependent on numerous variables, a primary controlling factor is the level of pre-planning and decision-making completed prior to chemical terrorist release. What follows is the first of a two-part analysis identifying key considerations, critical information, and decision criteria to facilitate post-attack and post-decontamination consequence management activities. A conceptual site model and human health-based exposure guidelines are developed and reported as an aid to site-specific pre-planning in the current absence of U.S. state or Federal values designated as compound-specific remediation or re-entry concentrations, and to safely expedite facility recovery to full operational status. Chemicals of concern include chemical warfare nerve and vesicant agents and the toxic industrial compounds phosgene, hydrogen cyanide, and cyanogen chloride. This work has been performed as a national case study conducted in partnership with the Los Angeles International Airport and The Bradley International Terminal. All recommended guidelines have been selected for consistency with airport scenario release parameters of a one-time, short-duration, finite airborne release from a single source followed by compound-specific decontamination.

13.
Analyst ; 133(5): 608-15, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18427681

RESUMO

A compact and low-power microcantilever-based sensor array has been developed and used to detect various chemical vapor analytes. In contrast to earlier micro-electro-mechanical systems (MEMS) array sensors, this device uses the static deflection of piezoresistive cantilevers due to the swelling of glassy polyolefin coatings during sorption of chemical vapors. To maximize the sensor response to a variety of chemical analytes, the polymers are selected based on their Hildebrand solubility parameters to span a wide range of chemical properties. We utilize a novel microcontact spotting method to reproducibly coat a single side of each cantilever in the array with the polymers. To demonstrate the utility of the sensor array we have reproducibly detected 11 chemical vapors, representing a breadth of chemical properties, in real time and over a wide range of vapor concentrations. We also report the detection of the chemical warfare agents (CWAs) VX and sulfur mustard (HD), representing the first published report of CWA vapor detection by a polymer-based, cantilever sensor array. Comparisons of the theoretical polymer/vapor partition coefficient to the experimental cantilever deflection responses show that, while general trends can be reasonably predicted, a simple linear relationship does not exist.


Assuntos
Poluentes Atmosféricos/análise , Substâncias para a Guerra Química/análise , Eletroquímica/métodos , Gases/análise , Medidas de Segurança , Eletroquímica/instrumentação , Eletrônica , Monitoramento Ambiental/instrumentação , Monitoramento Ambiental/métodos , Desenho de Equipamento , Polímeros , Volatilização
14.
Methods Enzymol ; 402: 402-22, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16401517

RESUMO

Accelerator mass spectrometry (AMS) traces isotopically labeled biochemicals and provides significant new directions for understanding molecular kinetics and dynamics in biological systems. AMS traces low-abundance radioisotopes for high specificity but detects them with MS for high sensitivity. AMS reduces radiation exposure doses to levels safe for use in human volunteers of all ages. Total radiation exposures are equivalent to those obtained in very short airplane flights, a commonly accepted radiation risk. Waste products seldom reach the Nuclear Regulatory Commission (NRC) definition of radioactive waste material for (14)C and (3)H. Attomoles of labeled compounds are quantified in milligram-sized samples, such as 20 microl of blood. AMS is available from several facilities that offer services and new spectrometers that are affordable. Detailed examples of designing AMS studies are provided, and the methods of analyzing AMS data are outlined.


Assuntos
Radioisótopos de Carbono , Espectrometria de Massas/métodos , Trítio , Radioisótopos de Carbono/sangue , Radioisótopos de Carbono/urina , Humanos , Aceleradores de Partículas , Trítio/sangue , Trítio/urina
15.
Chemosphere ; 57(10): 1257-64, 2004 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-15519370

RESUMO

Laboratory experiments were conducted to determine environmental variables that affect the affinities and persistence of the nerve agent O-ethyl S-(2-diisopropylaminoethyl) methylphosphonothiolate (VX) at dilute concentrations in environmental matrices. Quantitative analyses of VX and its degradation products were performed using LC-MS. Batch hydrolysis experiments demonstrated an increasing hydrolysis rate as pH increased, as shown in previous studies, but also indicated that dissolved aqueous constituents can cause significant differences in the absolute hydrolysis rate. Adsorption isotherms from batch aqueous experiments revealed that VX has a high affinity for hydrophobic organics, a moderate affinity for montmorillonite clay, and a very low affinity for an iron-oxyhydroxide soil mineral, goethite. The adsorption on goethite was increased with the presence of dissolved organic matter in solution. VX degraded rapidly when dried onto goethite, when specific adsorption was forced. No enhanced degradation occurred with goethite in small amounts of water. These results suggest that aqueous conditions have important controls on VX adsorption and degradation in the environment and a more mechanistic understanding of these controls is needed in order to enable accurate predictions of its long-term fate and persistence.


Assuntos
Substâncias para a Guerra Química/química , Meio Ambiente , Compostos Organotiofosforados/química , Adsorção , Cromatografia Líquida , Hidrólise , Compostos de Ferro , Espectrometria de Massas , Minerais , Fatores de Tempo
16.
Environ Sci Technol ; 37(19): 4330-5, 2003 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-14572081

RESUMO

Annual tritium exposures were reconstructed using tree cores from Pinus jeffreyi and Eucalyptus globulus near a tritiated water vapor release stack. Both tritium (3H) and carbon-14 (14C) from the wood were measured from milligram samples using accelerator mass spectrometry. Because the annual nature of the eucalyptus tree rings was in doubt, 14C measurements provided growth rates used to estimate the age for 3H determinations. A 30-yr comparison of organically bound tritium (OBT) levels to reported 3H release data is achieved using OBT measurements from three trees nearthe stack. The annual average 3H, determined from atmospheric water vapor monitoring stations, is comparable to the OBT in proximal trees. For situations without adequate historical monitoring data, this measurement-based historical assessment provides the only independent means of assessing exposure as compared to fate and transport models that require prior knowledge of environmental conditions and 3H discharge patterns.


Assuntos
Exposição Ambiental , Monitoramento Ambiental/métodos , Poluentes Ambientais/análise , Eucalyptus/crescimento & desenvolvimento , Modelos Teóricos , Pinus/crescimento & desenvolvimento , Trítio/análise , Poluentes Ambientais/farmacocinética , Pinus/química , Trítio/farmacocinética , Volatilização
17.
J Environ Eng (New York) ; 129(7): 659-666, 2003 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-20333267

RESUMO

Two sediment cores were collected from a marina in the San Francisco Bay to characterize historical sediment contamination resulting from the direct discharge of industrial wastewater from Naval Air Station Alameda. Depth profiles of trace metals, petroleum hydrocarbons, and radionuclides were determined with a 12-cm spacing down to a depth of 120 cm. The chronology of sediment accumulation is established by depth profiles of sedimentary time markers in conjunction with information on site history. The traditional approach of determining sediment accumulation rates by measuring atmospheric (210)Pb deposition was obscured by a larger source of (210)Pb in the sediments from the decay of anthropogenic (226)Ra, likely from luminescent paints used at this facility and released to the marina. The sedimentation rates inferred from the data indicate that the greatest amount of contamination by trace metals and petroleum hydrocarbons took place between 1940 and 1960. In addition, anthropogenic (226)Ra activities are positively correlated with some of the contaminants in the sediments, allowing the wastewater discharged from the facility to be distinguished from baywide contamination. In locations such as this, where there is a complex history of contaminant deposition, a source-specific tracer may be the only feasible method of attributing historical contamination to a point source.

18.
Environ Sci Technol ; 36(13): 2848-52, 2002 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-12144257

RESUMO

Public concerns over the health effects associated with low-level and long-term exposure to tritium released from industrial point sources have generated the demand for better methods to evaluate historical tritium exposure levels for these communities. The cellulose of trees accurately reflects the tritium concentration in the source water and may contain the only historical record of tritium exposure. The tritium activity in the annual rings of a tree was measured using accelerator mass spectrometry to reconstruct historical annual averages of tritium exposure. Milligram-sized samples of the annual tree rings from a Tamarix located at the Nevada Test Site are used for validation of this methodology. The salt cedar was chosen since it had a single source of tritiated water that was well-characterized as it varied over time. The decay-corrected tritium activity of the water in which the salt cedar grew closely agrees with the organically bound tritium activity in its annual rings. This demonstrates that the milligram-sized samples used in tritium accelerator mass spectrometry are suited for reconstructing anthropogenic tritium levels in the environment.


Assuntos
Monitoramento Ambiental/métodos , Espectrometria de Massas/métodos , Tamaricaceae/química , Trítio/análise , Celulose/química , Exposição Ambiental , Humanos , Saúde Pública , Sensibilidade e Especificidade , Tamaricaceae/crescimento & desenvolvimento , Trítio/química
19.
Anal Chem ; 74(24): 6285-90, 2002 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-12510750

RESUMO

The capability to prepare samples accurately and reproducibly for analysis of tritium (3H) content by accelerator mass spectrometry (AMS) greatly facilitates isotopic tracer studies in which attomole levels of 3H can be measured in milligram-sized samples. A method has been developed to convert the hydrogen of organic samples to a solid, titanium hydride, which can be analyzed by AMS. Using a two-step process, the sample is first oxidized to carbon dioxide and water. In the second step, the water is transferred within a heated manifold into a quartz tube, reduced to hydrogen gas using zinc, and reacted with titanium powder. The 3H/1H ratio of the titanium hydride is measured by AMS and normalized to standards whose ratios were determined by decay counting to calculate the amount of 3H in the original sample. Water, organic compounds, and biological samples with 3H activities measured by liquid scintillation counting were utilized to develop and validate the method. The 3H/1H ratios were quantified in samples that spanned 5 orders of magnitude, from 10(-10) to 10(-15), with a detection limit of 3.0 x 10(-15), which is equivalent to 0.02 dpm tritium/mg of material. Samples smaller than 2 mg were analyzed following addition of 2 mg of a tritium-free-hydrogen carrier. Preparation of organic standards containing both 14C and 3H in 2-mg organic samples demonstrated that this sample preparation methodology can also be applied to quantify both of these isotopes from a single sample.


Assuntos
Espectrometria de Massas/instrumentação , Espectrometria de Massas/métodos , Trítio/análise , DNA/química , Hidrogênio/análise , Fígado/química , Compostos Orgânicos/química , Aceleradores de Partículas , Plasma/química , Proteínas/química , Triglicerídeos/química , Urina/química
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