576 research outputs found
A Pinned Polymer Model of Posture Control
A phenomenological model of human posture control is posited. The dynamics
are modelled as an elastically pinned polymer under the influence of noise. The
model accurately reproduces the two-point correlation functions of experimental
posture data and makes predictions for the response function of the postural
control system. The physiological and clinical significance of the model is
discussed.Comment: uuencoded post script file, 17 pages with 3 figure
CRT: A numerical tool for propagating ultra-high energy cosmic rays through Galactic magnetic field models
Deflection of ultra high energy cosmic rays (UHECRs) by the Galactic magnetic
field (GMF) may be sufficiently strong to hinder identification of the UHECR
source distribution. A common method for determining the effect of GMF models
on source identification efforts is backtracking cosmic rays. We present the
public numerical tool CRT for propagating charged particles through Galactic
magnetic field models by numerically integrating the relativistic equation of
motion. It is capable of both forward- and back-tracking particles with varying
compositions through pre-defined and custom user-created magnetic fields. These
particles are injected from various types of sources specified and distributed
according to the user. Here, we present a description of some source and
magnetic field model implementations, as well as validation of the integration
routines.Comment: 12 pages, 9 figure
Programa de Conservación del Merino Negro: Caracterización de la aptitud productiva y valoración genética para caracteres de crecimiento
A pesar de que el merino negro como miembro del
tronco merino nativo español, ha sufrido la mayoría de
los vaivenes del merino blanco, no ha existido paralelismo
en la evolución de los censos de ambas poblaciones
a lo largo de la historia, principalmente debido al color de
su fibra.
En la actualidad está considerada una raza en peligro
de extinción. Dentro de las actuaciones llevadas a cabo
por la Asociación Nacional de Criadores para su conservación
in situ, y en el ámbito del proyecto de investigación
lNIA (RZ- 2004-00024), se ha realizado el control
productivo de 170 corderos hijos de 5 moruecos pertenecientes
al Censyra de Extremadura (Badajoz) que fueron
sometidos a prueba de descendencia. Se realizaron 4
pesadas por cordero desde el nacimiento hasta el sacrificio (edad media 75 días). La ganancia media diaria osciló
en el caso de los machos entre los 0,223 Kg. (ganancia
en el primer mes de vida) hasta los 0,265 Kg. (en la última
fase del cebo) y los 0,195 Kg. a 0,221 Kg. en los mismos
periodos para las hembras. Esto determinó que los
pesos medios obtenidos fueron en todos los casos estadísticamente
menores a los del merino blanco que se controla dentro del Esquema de Selección de la raza (alrededor
de 1 Kg. de media a los 30 días de edad, y 2 kgs. al
final del cebo). Esto justifica en parte la situación en la
que se encuentra actualmente esta raza. No obstante consideramos
que las diferencias detectadas son más bien un
reflejo de la diferente historia selectiva de ambas razas en
la última década. Finalmente se ha realizado la primera valoración genética de esta raza empleando la metodología
BLUP modelo animal para caracteres de crecimiento
utilizando para ello los mismos parámetros y modelo que
el merino blanco, contando en la actualidad con el valor
genético de 898 animales para 4 caracteres de crecimiento
(gmd hasta los 30 días y de 30 a los 75 dias, peso
a los 3O y 75 días), y la calificación morfológica
Evaluación de las necesidades hídricas de tres variedades de fresas y de su respuesta frente a un recorte hídrico moderado
Instituto Nacional de Investigaciones RTA2012-00001-00-00FEDER CC10-009-C02-0
Hypopituitarism and pregnancy : clinical characteristics, management and pregnancy outcome
Altres ajuts: Acord transformatiu CRUE-CSICAltres ajuts: Open Access Funding provided by Universitat Autonoma de Barcelona.Purpose: To describe the clinical characteristics, management and pregnancy outcome of women with prepregnancy hypopituitarism (HYPO) that received care at our center. Methods: Retrospective study describing 12 pregnancies in women with prepregnancy HYPO (two or more pituitary hormonal deficiencies under replacement treatment) that received care during pregnancy at Hospital Santa Creu i Sant Pau. Clinical characteristics, management and pregnancy outcome were systematically collected. Results: Average patients' age was 35 years and HYPO duration at the beginning of pregnancy was 19 years. The most frequent cause of HYPO was surgical treatment of a sellar mass (8 pregnancies). Eight pregnancies were in primigravid women and 10 required assisted reproductive techniques. The hormonal deficits before pregnancy were as follows: GH in 12 women, TSH in 10, gonadotropin in 9, ACTH in 5 and ADH in 2. All deficits were under hormonal substitution except for GH deficit in 4 pregnancies. During pregnancy, 4 new deficits were diagnosed. The dosage of replacement treatment for TSH, ACTH and ADH deficits was increased and GH was stopped. Average gestational age at birth was 40 weeks, gestational weight gain was excessive in 9 women, 8 patients required induction/elective delivery and cesarean section was performed in 6. Average birthweight was 3227 g. No major complications were observed. Five women were breastfeeding at discharge. Conclusions: In this group of women with long-standing HYPO, with careful clinical management (including treatment of new-onset hormonal deficits) pregnancy outcome was satisfactory but with a high rate of excessive gestational weight gain and cesarean section
Directed polymers in high dimensions
We study directed polymers subject to a quenched random potential in d
transversal dimensions. This system is closely related to the
Kardar-Parisi-Zhang equation of nonlinear stochastic growth. By a careful
analysis of the perturbation theory we show that physical quantities develop
singular behavior for d to 4. For example, the universal finite size amplitude
of the free energy at the roughening transition is proportional to (4-d)^(1/2).
This shows that the dimension d=4 plays a special role for this system and
points towards d=4 as the upper critical dimension of the Kardar-Parisi-Zhang
problem.Comment: 37 pages REVTEX including 4 PostScript figure
Update on the effects of antioxidants on diabetic retinopathy : In vitro experiments, animal studies and clinical trials
Current therapies for diabetic retinopathy (DR) incorporate blood glucose and blood pressure control, vitrectomy, photocoagulation, and intravitreal injections of anti-vascular endothelial growth factors or corticosteroids. Nonetheless, these techniques have not been demonstrated to completely stop the evolution of this disorder. The pathophysiology of DR is not fully known, but there is more and more evidence indicating that oxidative stress is an important mechanism in the progression of DR. In this sense, antioxidants have been suggested as a possible therapy to reduce the complications of DR. In this review we aim to assemble updated information in relation to in vitro experiments, animal studies and clinical trials dealing with the effect of the antioxidants on DR
From nonassociativity to solutions of the KP hierarchy
A recently observed relation between 'weakly nonassociative' algebras A (for
which the associator (A,A^2,A) vanishes) and the KP hierarchy (with dependent
variable in the middle nucleus A' of A) is recalled. For any such algebra there
is a nonassociative hierarchy of ODEs, the solutions of which determine
solutions of the KP hierarchy. In a special case, and with A' a matrix algebra,
this becomes a matrix Riccati hierarchy which is easily solved. The matrix
solution then leads to solutions of the scalar KP hierarchy. We discuss some
classes of solutions obtained in this way.Comment: 7 pages, 4 figures, International Colloquium 'Integrable Systems and
Quantum Symmetries', Prague, 15-17 June 200
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