341 research outputs found
Hot nuclear matter in the modified quark-meson coupling model with quark-quark correlations
Short-range quark-quark correlations in hot nuclear matter are examined
within the modified quark-meson coupling model (MQMC) by adding repulsive
scalar and vector quark-quark interactions. Without these correlations, the bag
radius increases with the baryon density. However when the correlations are
introduced the bag size shrinks as the bags overlap. Also as the strength of
the scalar quark-quark correlation is increased, the decrease of the effective
nucleon mass with the baryonic density is slowed down and tends to
saturate at high densities. Within this model we study the phase transition
from the baryon-meson phase to the quark-gluon plasma (QGP) phase with the
latter modeled as an ideal gas of quarks and gluons inside a bag. Two models
for the QGP bag parameter are considered. In one case, the bag is taken to be
medium-independent and the phase transition from the hadron phase to QGP is
found to occur at 5-8 times ordinary nuclear matter density for temperatures
less than 60 MeV. For lower densities, the transition takes place at higher
temperature reaching up to 130 MeV at zero density. In the second case, the QGP
bag parameter is considered medium-dependent as in the MQMC model for the
hadronic phase. In this case, it is found that the phase transition occurs at
much lower densities.Comment: 8 pages, latex, 4 eps figure
Exploración del mediastino anterior por herida con arma de fuego en la región precordial
Se describe por primera vez en el país, la realización de la operación de Milton, modificada por Duval-Barasty (Toraco-laparotomía media, con esterno y pericardiotomía, por herida de la región precordial con arma de fuego. Se transcriben la técnica clásica
Lineamientos a 2030 para la adaptación y mitigación al riesgo del aumento del nivel del mar (ANM) en el sector turístico del borde litoral de Cartagena de Indias-Colombia
Ponencia presentada en: VIII Congreso de la Asociación Española de Climatología celebrado en Salamanca entre el 25 y el 28 de septiembre de 2012.[ES]El ANM es uno de los efectos más contraproducentes del cambio climático en las costas
Colombianas. El borde litoral de Cartagena de Indias D. T y C, ha sufrido procesos de inundación y
erosión costera, especialmente en la zona comprendida entre Bocagrande y la Boquilla. Producto de
esto y de que no se observa una gestión integral para enfrentar el problema, se analizó la gestión
institucional del manejo del riesgo y la problemática asociada al ANM, para plantear lineamentos que
fortalecen procesos institucionales para la adaptación y mitigación con prospectiva a 20 años. En el
proceso, se evaluaron impactos ambientales generados y proyectados a 2030 y se caracterizó el
proceso de gestión institucional desarrollado en torno a esta temática.[EN]The sea level rise is one of the most counterproductive effects of climate change in Colombia’s
coast. The coastal edge of Cartagena has undergone flooding processes and coastal erosion especially
in the area between Bocagrande and La Boquilla. Based on this and the lack of an integral
management process to address the problem. We analyzed the institutional risk management and the
problems associated to the sea level rise in order to set guidelines that strengthen institutional
processes for adaptation and mitigation with 20 years prospective.
In the process, generated environmental impacts were evaluated and projected to 2030 and the
characterization of the institutional management process which was developed in relation to this
topic
Implementation Science Research Examining the Integration of Evidence-Based Practices Into HIV Prevention and Clinical Care: Protocol for a Mixed-Methods Study Using the Exploration, Preparation, Implementation, and Sustainment (EPIS) Model
BACKGROUND: The Exploration, Preparation, Implementation, and Sustainment (EPIS) model is an implementation framework for studying the integration of evidence-based practices (EBPs) into real-world settings. The EPIS model conceptualizes implementation as a process starting with the earliest stages of problem recognition (Exploration) through the continued use of an EBP in a given clinical context (Sustainment). This is the first implementation science (IS) study of the integration of EBPs into adolescent HIV prevention and care settings.
OBJECTIVE: This protocol (ATN 153 EPIS) is part of the Scale It Up program, a research program administered by the Adolescent Medicine Trials Network for HIV/AIDS Interventions (ATN), described in this issue by Naar et al. The EPIS study is a descriptive study of the uptake of 4 EBPs within the Scale It Up program. The goal of EPIS is to understand the barriers and facilitators associated with the Preparation, Implementation, and Sustainment of EBPs into HIV prevention and clinical care settings.
METHODS: The EPIS study is a convergent parallel mixed-methods IS study. Key implementation stakeholders, that is, clinical care providers and leaders, located within 13 ATN sites across the United States will complete a qualitative interview conducted by telephone and Web-based surveys at 3 key implementation stages. The Preparation assessment occurs before EBP implementation, Implementation occurs immediately after sites finish implementation activities and prepare for sustainment, and Sustainment occurs 1 year postimplementation. Assessments will examine stakeholders\u27 perceptions of the barriers and facilitators to EBP implementation within their clinical site as outlined by the EPIS framework.
RESULTS: The EPIS baseline period began in June 2017 and concluded in May 2018; analysis of the baseline data is underway. To date, 153 stakeholders have completed qualitative interviews, and 91.5% (140/153) completed the quantitative survey.
CONCLUSIONS: The knowledge gained from the EPIS study will strengthen the implementation and sustainment of EBPs in adolescent prevention and clinical care contexts by offering insights into the barriers and facilitators of successful EBP implementation and sustainment in real-world clinical contexts
Study Protocol For Clinical Trial of the Fit Families Multicomponent Obesity intervention For african american adolescents and their Caregivers: Next Step From the orbit initiative
INTRODUCTION: This study will test the effectiveness of FIT Families (FIT), a multicomponent family-based behavioural intervention, against a credible attention control condition, Home-Based Family Support (HBFS). This protocol paper describes the design of a randomised clinical trial testing the efficacy of the FIT intervention. The protocol will assess the efficacy of FIT to improve health status in African American adolescents with obesity (AAAO) and their primary caregivers on primary (percent body fat) and secondary (physical activity, metabolic control, weight loss) outcomes and its cost-effectiveness.
METHODS: 180 youth/caregiver dyads are randomised into FIT or HBFS, stratified by age, gender and baseline per cent overweight. The proposed study follows a two condition (FIT, HBFS) by four assessment time points. Tests will be conducted to identify potential relationship of baseline demographic and clinical variables to our dependent variables and see whether they are balanced between groups. It is hypothesised that youth/caregiver dyads randomised to FIT will show significantly greater reductions in percent body fat over a 12-month follow-up period compared with AAAO receiving HBFS. Preliminary findings are expected by November 2023.
ETHICS: This protocol received IRB approval from the Medical University of South Carolina (Pro00106021; see \u27MUSC IRB 106021 Main Approval.doxc\u27 in online supplemental materials).
DISSEMINATION: Dissemination activities will include summary documents designed for distribution to the broader medical community/family audience and submission of manuscripts, based on study results, to relevant peer-reviewed scientific high-impact journals.
TRIAL REGISTRATION NUMBER: NCT04974554
Finite Temperature Quark Matter and Supernova Explosion
We study the equation of state of quark matter at finite temperature, using a
confinement model in which chiral symmetry remains broken in the deconfined
phase. Implications for type II supernova explosion and for the structure and
evolution of the proto-neutron star are discussed.Comment: RevTeX file + 5 postscript figure
Characterization of Marine Aerosol for Assessment of Human Exposure to Brevetoxins
Red tides in the Gulf of Mexico are commonly formed by the fish-killing dinoflagellate Karenia brevis, which produces nine potent polyether brevetoxins (PbTxs). Brevetoxins can be transferred from water to air in wind-powered white-capped waves. Inhalation exposure to marine aerosol containing brevetoxins causes respiratory symptoms. We describe detailed characterization of aerosols during an epidemiologic study of occupational exposure to Florida red tide aerosol in terms of its concentration, toxin profile, and particle size distribution. This information is essential in understanding its source, assessing exposure to people, and estimating dose of inhaled aerosols. Environmental sampling confirmed the presence of brevetoxins in water and air during a red tide exposure period (September 2001) and lack of significant toxin levels in the water and air during an unexposed period May 2002). Water samples collected during a red tide bloom in 2001 showed moderate-to-high concentrations of K. brevis cells and PbTxs. The daily mean PbTx concentration in water samples ranged from 8 to 28 μg/L from 7 to 11 September 2001; the daily mean PbTx concentration in air samples ranged from 1.3 to 27 ng/m(3). The daily aerosol concentration on the beach can be related to PbTx concentration in water, wind speed, and wind direction. Personal samples confirmed human exposure to red tide aerosols. The particle size distribution showed a mean aerodynamic diameter in the size range of 6–12 μm, with deposits mainly in the upper airways. The deposition pattern correlated with the observed increase of upper airway symptoms in healthy lifeguards during the exposure periods
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Effective elastic thickness of the lithosphere along the Easter Seamount Chain
Bathymetry and gravity data collected during Legs 5, 6, and 7 of the 1993 GLORIA Expedition and the recently released 2-min altimetry-derived global gravity grid are used to determine the effective elastic thickness of the lithosphere along the Easter Seamount Chain (ESC). Forward modeling, admittance, and coherence methods yield consistent results. With the exception of the eastern and western ends of the ESC the effective elastic thickness along the chain is similar to 1-4 km. The thin elastic thickness for the majority of the ESC seamounts is compatible with a young seafloor age at the time of loading derived from new radiometric ages of the seamounts along the chain and a magnetic isochron age interpretation of the Nazca plate seafloor age. The elastic thickness southeast of the Nazca fracture zone is similar to 6 km, apparently because of the seafloor age discontinuity across the fracture zone. The elastic thickness near the San Felix Island, at the eastern end of the ESC, is even greater (similar to 11 km), which is compatible with the estimated seafloor age at the time of loading. A slight increase in the effective elastic thickness of the far western part of the ESC suggests dynamic compensation or less thermal weakening of lithosphere above a plume channel versus directly above the plume center. These findings combined with published geochemistry support a hotspot origin for the ESC, complicated by large-scale plate boundary reorganizations and channeling of plume material to the East Pacific Rise
Modified Quark-Meson Coupling Model for Nuclear Matter
The quark-meson coupling model for nuclear matter, which describes nuclear
matter as non-overlapping MIT bags bound by the self-consistent exchange of
scalar and vector mesons, is modified by introducing medium modification of the
bag constant. We model the density dependence of the bag constant in two
different ways: one invokes a direct coupling of the bag constant to the scalar
meson field, and the other relates the bag constant to the in-medium nucleon
mass. Both models feature a decreasing bag constant with increasing density. We
find that when the bag constant is significantly reduced in nuclear medium with
respect to its free-space value, large canceling isoscalar Lorentz scalar and
vector potentials for the nucleon in nuclear matter emerge naturally. Such
potentials are comparable to those suggested by relativistic nuclear
phenomenology and finite-density QCD sum rules. This suggests that the
reduction of bag constant in nuclear medium may play an important role in low-
and medium-energy nuclear physics.Comment: Part of the text is reordered, revised version to appear in Phys.
Rev. C. 19 pages, ReVTeX, 4 figures embedde
Excluded Volume Effects in the Quark Meson Coupling Model
Excluded volume effects are incorporated in the quark meson coupling model to
take into account in a phenomenological way the hard core repulsion of the
nuclear force. The formalism employed is thermodynamically consistent and does
not violate causality. The effects of the excluded volume on in-medium nucleon
properties and the nuclear matter equation of state are investigated as a
function of the size of the hard core. It is found that in-medium nucleon
properties are not altered significantly by the excluded volume, even for large
hard core radii, and the equation of state becomes stiffer as the size of the
hard core increases.Comment: 14 pages, revtex, 6 figure
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