RESUMEN
We present measurements of the cross section and double-helicity asymmetry A_{LL} of direct-photon production in p[over â]+p[over â] collisions at sqrt[s]=510 GeV. The measurements have been performed at midrapidity (|η|<0.25) with the PHENIX detector at the Relativistic Heavy Ion Collider. At relativistic energies, direct photons are dominantly produced from the initial quark-gluon hard scattering and do not interact via the strong force at leading order. Therefore, at sqrt[s]=510 GeV, where leading-order-effects dominate, these measurements provide clean and direct access to the gluon helicity in the polarized proton in the gluon-momentum-fraction range 0.02Asunto(s)
Alimentos
, Fotones
, Movimiento (Física)
RESUMEN
Studying spin-momentum correlations in hadronic collisions offers a glimpse into a three-dimensional picture of proton structure. The transverse single-spin asymmetry for midrapidity isolated direct photons in p^{↑}+p collisions at sqrt[s]=200 GeV is measured with the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC). Because direct photons in particular are produced from the hard scattering and do not interact via the strong force, this measurement is a clean probe of initial-state spin-momentum correlations inside the proton and is in particular sensitive to gluon interference effects within the proton. This is the first time direct photons have been used as a probe of spin-momentum correlations at RHIC. The uncertainties on the results are a 50-fold improvement with respect to those of the one prior measurement for the same observable, from the Fermilab E704 experiment. These results constrain gluon spin-momentum correlations in transversely polarized protons.
RESUMEN
Systemic and coronary hemodynamic parameters were determined during an arrhythmia and immediately after a direct current transthoracic shock given in an attempt to convert the arrhythmia to a sinus mechanism. No anesthesia or drugs were administered between the two studies. 16 patients with atrial fibrillation converted to sinus rhythm and five did not. In two patients with atrial flutter and one with supraventricular tachycardia, the arrhythmia was corrected. The arrhythmia persisted in a single patient with ventricular tachycardia. Utilizing each patient as his own control, we compared statistically various hemodynamic parameters before and after the shock. In addition, the group of patients whose atrial fibrillation terminated was compared to the group treated in the same manner but in which the atrial fibrillation persisted. Pressures in the right side of the heart decreased in both groups so that the changes appeared to be caused by factors associated with the transthoracic direct current shock or the catheterization procedure. The differences between those with atrial fibrillation who converted to sinus rhythm as compared to those who did not were a decrease in heart rate, an increase in stroke volume, and an increase in cardiac efficiency. There was no immediate effect on the cardiac output or coronary blood flow.
Asunto(s)
Arritmias Cardíacas/fisiopatología , Cardioversión Eléctrica , Hemodinámica , Adulto , Arritmias Cardíacas/terapia , Fibrilación Atrial/fisiopatología , Dióxido de Carbono/sangre , Cateterismo Cardíaco , Gasto Cardíaco , Vasos Coronarios , Técnica de Dilución de Colorante , Femenino , Frecuencia Cardíaca , Humanos , Masculino , Persona de Mediana Edad , Oxígeno/sangre , Flujo Sanguíneo Regional , Taquicardia/fisiopatologíaRESUMEN
Exercise training may be useful for a variety of patients with and without established cardiovascular disease. The degree to which a patient participates in a prescribed exercise program depends strongly on initial motivation. The primary care physician can provide appropriate reinforcement with careful explanation of the effects of exercise on cardiovascular and metabolic function. Exercise programs may be combined effectively with other life-style adjustments, including weight loss, blood pressure control, and discontinuation of smoking. As a single intervention factor, exercise cannot prevent the evolution of cardiovascular disease in multiple-risk patients. Exercise is best used in combination with a program of comprehensive cardiovascular risk factor modification.
Asunto(s)
Rehabilitación Cardiaca , Terapia por Ejercicio , Adulto , Presión Sanguínea , Gasto Cardíaco , Enfermedades Cardiovasculares/fisiopatología , Prueba de Esfuerzo , Frecuencia Cardíaca , Humanos , Persona de Mediana Edad , Educación y Entrenamiento Físico , Esfuerzo Físico , Pulso Arterial , RiesgoAsunto(s)
Electrocardiografía , Cardiopatías/diagnóstico , Potasio , Adulto , Ansiedad , Enfermedad Coronaria/diagnóstico , Diagnóstico Diferencial , Reacciones Falso Positivas , Femenino , Humanos , Hiperventilación/diagnóstico , Masculino , Persona de Mediana Edad , Miocarditis/diagnóstico , Pericarditis/diagnóstico , Esfuerzo Físico , Postura , Potasio/farmacología , Sodio/farmacologíaAsunto(s)
Fibroma , Neoplasias Cardíacas , Adolescente , Angiocardiografía , Cateterismo Cardíaco , Electrocardiografía , Circulación Extracorporea , Femenino , Fibroma/diagnóstico , Fibroma/diagnóstico por imagen , Fibroma/cirugía , Neoplasias Cardíacas/diagnóstico , Neoplasias Cardíacas/diagnóstico por imagen , Neoplasias Cardíacas/cirugía , Ventrículos Cardíacos , HumanosAsunto(s)
Presión Sanguínea/efectos de los fármacos , Gasto Cardíaco/efectos de los fármacos , Frecuencia Cardíaca/efectos de los fármacos , Fenitoína/farmacología , Circulación Pulmonar/efectos de los fármacos , Resistencia Vascular/efectos de los fármacos , Animales , Circulación Sanguínea/efectos de los fármacos , Perros , Hematócrito , Consumo de OxígenoAsunto(s)
Fibrilación Atrial/fisiopatología , Circulación Sanguínea/efectos de los fármacos , Gasto Cardíaco , Perros , Estimulación Eléctrica , Corazón/efectos de los fármacos , Hemodinámica , Consumo de Oxígeno/efectos de los fármacos , Propranolol/farmacología , Simpaticolíticos/farmacología , AnimalesAsunto(s)
Sistema Cardiovascular/efectos de los fármacos , Miocardio/metabolismo , Vasopresinas/farmacología , Animales , Presión Sanguínea/efectos de los fármacos , Determinación de la Presión Sanguínea , Bradicardia/etiología , Gasto Cardíaco/efectos de los fármacos , Perros , Corazón/efectos de los fármacos , Frecuencia Cardíaca , Hemodinámica , Hipoxia/etiología , Inyecciones Intravenosas , Lactatos/sangre , Oxígeno/sangre , Consumo de Oxígeno/efectos de los fármacos , Respiración/efectos de los fármacos , Resistencia Vascular/efectos de los fármacos , Vasoconstrictores/farmacologíaAsunto(s)
Angiografía , Gasto Cardíaco/efectos de los fármacos , Medios de Contraste/farmacología , Animales , Presión Sanguínea/efectos de los fármacos , Bradicardia/inducido químicamente , Diatrizoato/farmacología , Perros , Inyecciones Intraarteriales , Taquicardia/inducido químicamente , Fibrilación Ventricular/inducido químicamenteAsunto(s)
Trastornos por Estrés Postraumático/terapia , Terrorismo/psicología , Miedo , Pesar , Humanos , Estados UnidosRESUMEN
A 10-year-old boy who had portal hypertension secondary to portal fibrosis/intrahepatic biliary atresia developed syncopal episodes related to strenuous activity. A work-up excluded a metabolic or neurologic etiology and cardiac catheterization demonstrated significant pulmonary hypertension. Six months later he died and an autopsy revealed pulmonary plexogenic arteriopathy without microemboli. Previous reported cases of this symptom complex are reviewed. In addition, he had a history of nonspecific colitis, ulcerative stomatitis, and conjunctivitis responsive to steroid therapy. The possible relationship of these manifestations to the portal pulmonary pathology is discussed.