1,438 research outputs found
Equivalence between various versions of the self-dual action of the Ashtekar formalism
Different aspects of the self-dual (anti-self-dual) action of the Ashtekar
canonical formalism are discussed. In particular, we study the equivalences and
differences between the various versions of such an action. Our analysis may be
useful for the development of an Ashtekar formalism in eight dimensions.Comment: 10 pages, Latex, minor correction
Towards an Ashtekar formalism in eight dimensions
We investigate the possibility of extending the Ashtekar theory to eight
dimensions. Our approach relies on two notions: the octonionic structure and
the MacDowell-Mansouri formalism generalized to a spacetime of signature 1+7.
The key mathematical tool for our construction is the self-dual (antiself-dual)
four-rank fully antisymmetric octonionic tensor. Our results may be of
particular interest in connection with a possible formulation of M-theory via
matroid theory.Comment: 15 pages, Latex, minor changes, to appear in Class. Quantum Gra
Hamiltonian Noether theorem for gauge systems and two time physics
The Noether theorem for Hamiltonian constrained systems is revisited. In
particular, our review presents a novel method to show that the gauge
transformations are generated by the conserved quantities associated with the
first class constraints. We apply our results to the relativistic point
particle, to the Friedberg et al. model and, with special emphasis, to two time
physics.Comment: 20 pages, Latex, references added, the "massless" sense of (87) is
clarifie
Binding of retinoids to uteroglobin
AbstractUteroglobin, a progesterone-binding secretory protein, was shown to bind retinoic acid and retinol in a non-saturable manner, at least up to concentrations of retinoids of 20 μM. Binding is increased about 10-fold by previous reduction of uteroglobin with 10 mM dithothreitol and it is not affected by previous saturation of the progesterone binding site, suggesting different binding sites for the steroid and the retinoids. The results are discussed in relation to a possible physiological role for this protein
Efecto del ejercicio sobre las subpoblaciones HDL, la enzima lecitina-colesterol acil-transferasa y la proteína transportadora de ésteres de colesterol en estudiantes de Medicina
ResumenObjetivoEvaluar el efecto del ejercicio físico sobre los niveles de las subpoblaciones HDL, enzima lecitina-colesterol acil-transferasa y la proteína transportadora de ésteres de colesterol en estudiantes de Medicina.MétodoLa población se dividió de manera voluntaria en 2 grupos: ejercicio y no ejercicio. Se midieron perímetro abdominal e índice de masa corporal, subfracciones de HDL2 y HDL3 por precipitación iónica, y enzima lecitina-colesterol acil-transferasa y proteína transportadora de ésteres de colesterol mediante Enzyme-Linked Immuno Sorbent Assay (ELISA).ResultadosEl perfil lipídico de riesgo aumentó en ambos grupos: las HDL, HDL3 y HDL2 disminuyeron en ambos grupos, pero solo las HDL2 lo hicieron de forma significativa en el grupo que realizó ejercicio. La lecitina-colesterol acil-transferasa y la proteína transportadora de ésteres de colesterol permanecieron sin cambios significativos. Sin embargo, en el grupo que hizo ejercicio hubo disminución estadísticamente significativa de HDL2 y lecitina-colesterol acil-transferasa, en las mujeres.ConclusionesEl ejercicio logra modificar algunas variables como el perímetro abdominal, el índice de masa corporal y las HDL3. Estas modificaciones son dependientes del género, pero, a pesar de la intervención de 3 meses con un programa de ejercicio, este no logra reducir los factores de riesgo lipídico en esta población de estudiantes de Medicina, debido a que su entorno hace muy compleja la respuesta metabólica al ejercicio.AbstractObjectiveTo evaluate exercise effect on HDL subpopulations, lecithin-cholesterol acyltransferase enzyme and ester transfer protein cholesterol levels in medical students.MethodPopulation was divided voluntarily into 2 groups, exercise and no exercise. Waist circumference and body mass index were measured; subfractions HDL2 and HDL3 by ion precipitation and LCAT and CETP enzymes Enzyme-Linked Immuno-Sorbent Assay (ELISA).ResultsLipidrisk profile increased in both groups; HDL, HDL2 and HDL3 decreased in both groups, but only the HDL2 decreased significantly in students who exercised. LCAT and CETP remained without significant changes, however, in the exercise group, there was statistically significant decrease in HDL2 and LCAT in women.ConclusionsThis study shows that exercise does alter some variables such as waist circumference, body mass index and HDL3. These changes are dependent on gender, but despite the intervention of 3 months with an exercise program, it fails reducing lipid risk factors in this medical student populations, given their environment, which complicates their metabolic response to exercise
Enfermedad meningocócica e impacto de la vacunación sistemática con la vacuna conjugada antimeningocócica C en el área sanitaria de Andalucía
comenzó en julio de 2000 la vacunación con vacuna conjugada antimeningocócica
C de todos los niños nacidos con posterioridad al 1 de
enero de 1995, y en septiembre de 2001 se amplíó a los nacidos a partir
del 1 de enero de 1991, esto es, hasta los 10 años de edad. El objetivo
de este trabajo es valorar la efectividad de esta vacuna tras su
introducción masiva en los niños del área geográfica de un distrito
sanitario, midiendo su impacto.
Métodos: Mediante un estudio longitudinal retrospectivo de
incidencia poblacional se calculan las coberturas vacunales de los
niños nacidos entre los años 1991 y 2001 y las tasas de incidencia de
los casos declarados de enfermedad meningocócica en siete temporadas
epidemiológicas (1997/98 a 2003/04). El impacto de la vacunación
frente a la meningitis del serogrupo C se calcula comparando
las tasas promedios anuales de las temporadas previas y posteriores
a las campañas de vacunación en la población menor y mayor de 10
años, utilizando el test exacto de Fisher.
Resultados: En el periodo de estudio se declararon 109 casos de
enfermedad meningocócica, de los que 50 eran de meningitis C. A
partir de la temporada 2000-2001 descendió la incidencia de meningitis
C en los niños menores de 10 años. En este grupo de edad se
encuentran diferencias significativas entre las tasas promedio anual
de las temporadas prevacunales y postvacunales (de 8,2 a 2,0 por
100.000 habitantes). En la población mayor de 10 años no se observa
este descenso en la incidencia. En el periodo de estudio no se ha
declarado ningún caso de fallo vacunal.
Conclusiones: La ausencia de fallos vacunales y la disminución
de la incidencia de enfermedad meningocócica C en los niños menores
de 10 años sugiere la buena efectividad de esta nueva vacuna conjugada
frente al meningococo
Nota corta. Aplicación de la ultrasonografía transrectal en el diagnóstico precoz de gestación y evaluación de la mortalidad embrionaria/fetal en ciervas ibéricas mantenidas en granja
[EN]: The main objective of the present study was to evaluate the accuracy of the trans-rectal ultrasonography technique applied to the Iberian red deer hinds since it has not been previously documented in Spain. Experimentation was also used to test the hypothesis that a lower fertility in young hinds could be due to an increment in embryonic or foetal mortality. For this purpose, 116 hinds divided in three groups depending on its age (young, adults and senescent) were examined by rectal ultrasonography and the different foetal structures measured two months after the males were removed from the groups of hinds. With these data, specificity and predictive value of negative diagnoses of the technique has been calculated. Trans-rectal ultrasonography is an accurate technique to use in Iberian red deer dams with overall levels of pregnant detection near to 92%. Finally, the youngest hinds showed poorer fertility rates (17.24% vs. 59.30% and 58.33% of senescent and prime-age respectively) and also higher of embryonic or foetal mortality (2 deaths out of 7 positive pregnant diagnoses compared with no deaths in the senescent group and 4 deaths out of 39 positive pregnant diagnoses in the prime-age group).[ES]: El objetivo principal del presente estudio ha sido evaluar la precisión de la ultrasonografía transrectal aplicada a las
ciervas ibéricas, ya que no ha sido documentado previamente en España. Paralelamente, se ha intentado comprobar la
hipótesis de que la menor fertilidad en las hembras más jóvenes podría deberse a una mayor mortalidad embrionariofetal.
Para ello, 116 hembras divididas en tres grupos en función de su edad (jóvenes, adultas y viejas) fueron ecografiadas
a los 2 meses de la retirada de los machos y medidas las diferentes estructuras fetales. Con estos datos se ha
calculado la especificidad y seguridad en el diagnóstico negativo de la técnica. La ultrasonografía transrectal es una
técnica precisa para su uso en ciervas ibéricas, con niveles de detección de gestación cercanos al 92%. Finalmente, las
ciervas más jóvenes muestran peores índices de fertilidad (17,24% vs 59,30% y 58,33% del grupo de viejas y adultas
respectivamente) y mayores mortalidades embrionario-fetales (2 muertes de 7 diagnósticos gestantes positivos en
comparación con ninguna muerte en el grupo de hembras de más edad y con 4 muertes de 39 diagnósticos gestantes
en las hembras adultas).Peer Reviewe
Exercises using a touchscreen tablet application improved functional ability more than an exercise program prescribed on paper in people after surgical carpal tunnel release: a randomised trial
Question: In people who have undergone surgical carpal tunnel release, do sensorimotor-based exercises performed on the touchscreen of a tablet device improve outcomes more than a conventional home exercise program prescribed on paper? Design: Randomised, parallel-group trial with concealed allocation, assessor blinding, and intention-to-treat analysis. Participants: Fifty participants within 10 days of surgical carpal tunnel release. Intervention: Each participant was prescribed a 4-week home exercise program. Participants in the experimental group received the ReHand tablet application, which administered and monitored exercises via the touchscreen. The control group was prescribed a home exercise program on paper, as is usual practice in the public hospital system. Outcome measures: The primary outcome was functional ability of the hand, reported using the shortened form of the Disabilities of the Arm, Shoulder and Hand (QuickDASH) questionnaire. Secondary outcomes were grip strength, pain intensity measured on a 10-cm visual analogue scale, and dexterity measured with the Nine-Hole Peg Test. Outcomes were measured by a blinded assessor at baseline and at the end of the 4-week intervention period. Results: At Week 4, functional ability improved significantly more in the experimental group than the control group (MD –21, 95% CI –33 to –9) on the QuickDASH score (0 to 100). Although the mean estimates of effect on the secondary outcome also all favoured the experimental group, none reached statistical significance: grip strength (MD 5.6 kg, 95% CI –0.5 to 11.7), pain (MD –1.4 cm, 95% CI –2.9 to 0.1), and dexterity (MD –1.3 seconds, 95% CI –3.7 to 1.1). Conclusion: Use of the ReHand tablet application for early rehabilitation after carpal tunnel release is more effective in the recovery of functional ability than a conventional home exercise program. It remains unclear whether there are any benefits in grip strength, pain or dexterity. Trial registration: ACTRN12618001887268
Anemia profile in critical septic patients hospitalized in the ICU
This article is part of the supplement: 31st International Symposium on Intensive Care and Emergency MedicineThe aim was to describe the anemia profile of medical or surgical patients with severe sepsis or septic shock in the ICU, assessing severity scale, length of stay and mortality. The prevalence of microcytic anemia is more than one-half of our septic patients. There are iron metabolism disorders without significant differences between medical and surgical patients. Transferrin, a protein related to malnutrition, inflammatory response and organ dysfunction, is significantly lower in the most severe patients with higher organ dysfunction scores.Ye
Self-dual gravity and self-dual Yang-Mills in the context of Macdowell-Mansouri formalism
In this work we propose an action which unifies self-dual gravity and
self-dual Yang-Mills in the context of the Macdowell-Mansouri formalism. We
claim that such an action may be used to find the S-dual action for both
self-dual gravity and self-dual Yang-Mills.Comment: 8 pages, Revtex, no figures, submitted to Phys. Rev.
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