Swinging Atwood's Machine: Experimental and Theoretical Studies

A Swinging Atwood Machine (SAM) is built and some experimental results concerning its dynamic behaviour are presented. Experiments clearly show that pulleys play a role in the motion of the pendulum, since they can rotate and have non-negligible radii and masses. Equations of motion must therefore take into account the inertial momentum of the pulleys, as well as the winding of the rope around them. Their influence is compared to previous studies. A preliminary discussion of the role of dissipation is included. The theoretical behaviour of the system with pulleys is illustrated numerically, and the relevance of different parameters is highlighted. Finally, the integrability of the dynamic system is studied, the main result being that the Machine with pulleys is non-integrable. The status of the results on integrability of the pulley-less Machine is also recalled.Comment: 37 page

Concentración de TSH endógena : un nuevo test para el diagnóstico de hipotiroidismo canino

Desde hace varios años disponemos del test para calcular la concentración de tirotropina (TSH) endógena canina. Los estudios publicados hasta el momento coinciden en que se trata de una prueba útil para el diagnóstico del hipotiroidismo en el perro. La concentración basal de TSH canina presenta una sensibilidad moderada (70%) y una especificidad alta (90%). Aunque la interpretación conjunta de los niveles de tiroxina (T4) total y de TSH aporta una buena eficacia diagnóstica, es conveniente descartar enfermedades no tiroideas antes de realizar estas pruebas hormonales. Cuando se evalúa un perro con un cuadro clínico compatible de hipotiroidismo, una concentración baja de T4 Y alta de TSH confirma el diagnóstico.An assay for determination of canine thyrotropin (cTSH) has become available a few years ago. Recent studies agree that determination of cTSH is a useful test for the diagnosis of hypothyroidism in dogs. The basal eTSH concentration has a moderate sensitivity (70%) and a high specificity (90%). Although the interpretation of both thyroxine (T4) and cTSH concentrations provides a good diagnostic accuracy, is suitable to rule out non-thyroidal illnesses before performing thyroid functíon tests. When evaluating a dog with clinical signs consistent with hypothyroidism, the finding of a low thyroxine concentration (T4) and a high eTSH concentration in a dog confirms the diagnosis

Análisis sobre la influencia de la densidad en la termografía de infrarrojos y el alcance de esta técnica en la detección de defectos internos en la madera

This paper shows the results of a laboratory phase for the determination of the 1limits of infrared thermography in detecting internal defects in wood and, furthermore, it analyses how the density of this material can influence the surface temperature displayed in a thermogram. To this end, experimental work is carried out whereby a series of work and environmental parameters are monitored (such as environmental temperature, relative humidity, distance to target), and the process is systematized by using pieces of different wood species (different densities) and by devising a set of samples for which various possible cases are analysed in terms of size and internal position of the damage. Similarly, using these samples, a study has been conducted on the effect on the thermal image produced by an increase of humidity inside the defect phenomena normally associated with wood decay.En el presente artículo se muestran los resultados obtenidos en una fase de laboratorio al tratar de determinar el alcance de la termografía de infrarrojos en la detección de defectos internos en la madera y, por otro lado, cómo interviene la densidad de este material sobre la temperatura superficial mostrada en un termograma. Para ello se ha desarrollado un trabajo experimental donde se han controlado una serie de parámetros ambientales y de trabajo (temperatura ambiente, humedad relativa, distancia al objetivo…), y se ha sistematizado el proceso utilizando piezas de distintas especies de madera (distintas densidades) y diseñando una serie de probetas donde se han analizado varias casuísticas posibles en cuanto a tamaño y posición interna de los daños. Análogamente, sobre estas probetas se ha estudiado el efecto que produce sobre la imagen termográfica un incremento de humedad interna en el defecto asociada normalmente a los fenómenos de pudrición de la madera

First Record of Leea guineensis (Vitaceae) in Cuban Scientific Literature

The presence of Leea guineensis G. Don. was confirmed in Cuba. It is a widely cultivated alochtonous species used in Cuba as ornameltal plants, which had not been previously registered in the scientific literature of the country. Several botanical procedures (collections, specialized catalogs, descriptions, and scientific illustrations) were applied. It is a new taxon of the genus in the country. A key is suggested as a way to distinguish it from other genera of the Vitaceae family

P10 25. ¿Aumenta la extracción endoscópica de vena safena las complicaciones inmediatas en los pacientes coronarios?

ObjetivoEn 2009 se ha empleado en nuestro centro la extracción endoscópica de vena safena (EEVS). Analizamos si tiene un impacto inmediato en infarto perioperatorio y supervivencia.Material y métodosSe han analizado todos los pacientes coronarios aislados intervenidos en 2009. Se emplearon el Vasoview 6 y Hemopro.La duración de la intervención, estancia en unidad de cuidados intensivos (UCI), troponina postoperatoria y necesidad de aminas fueron comparadas en ambos grupos.ResultadosFueron intervenidos 291 pacientes de revascularización coronaria aislada, con un 28,5% de EEVS.Edad media 67,38 (36-83), varones 79,4%. El 47,6% fue cirugía sin bomba extracorpórea. Mortalidad global del 2,9%. Se realizaron una media de 2,64 (desviación estándar [DE] 0,904) injertos/paciente, con un tiempo total medio de quirófano de 5,83 h (DE 1,18).No precisó soporte inotrópico el 65%, y a dosis bajas en el 25,6%. Troponina máxima 0,701 (0,1-12,5). Estancia mediana en UCI 1 día (1-30).La duración de la intervención fue significativamente mayor en los pacientes con EEVS (5,68 h vs 6,41 h; p = 0,005).La troponina máxima fue ligeramente superior en el grupo de extracción convencional (0,73 vs 0,65; p = 0,667), no significativa. No hubo diferencias significativas en duración media del ingreso en UCI, ni en necesidad de soporte inotrópico.ConclusiónLa EEVS no produce repercusión precoz en cuanto a infarto perioperatorio/duración de UCI, aunque se precisa seguimiento para estimar diferencias a largo plazo.La EEVS prolonga la duración de la intervención dada su mayor complejidad técnica

Stability of excited states of a Bose-Einstein condensate in an anharmonic trap

We analyze the stability of non-ground nonlinear states of a Bose-Einstein condensate in the mean field limit in effectively 1D (``cigar-shape'') traps for various types of confining potentials. We find that nonlinear states become, in general, more stable when switching from a harmonic potential to an anharmonic one. We discuss the relation between this fact and the specifics of the harmonic potential which has an equidistant spectrum

Growth Hormone Receptor Signaling Pathways and its Negative Regulation by SOCS2

Growth hormone (GH) is a critical regulator of linear body growth during childhood but continues to have important metabolic actions throughout life. The GH receptor (GHR) is ubiquitously expressed, and deficiency of GHR signaling causes a dramatic impact on normal physiology during somatic development, adulthood, and aging. GHR belongs to a family of receptors without intrinsic kinase activity. However, GH binding to homodimers of GHR results in a conformational change in the receptors and the associated tyrosine kinase Janus kinase 2 (JAK2) molecules. Activated JAK2 phosphorylates the GHR cytoplasmic domain on tyrosine residues, and subsequent JAK2-dependent and JAK2-independent intracellular signal transduction pathways evoke cell responses including changes in gene transcription, proliferation, cytoskeletal reorganization, and lipid and glucose metabolism. JAK2 phosphorylates STAT5b, which is a key transcription factor in GH regulation of target genes associated with body growth, intermediate metabolism, and gender dimorphism; although STAT1, 3, and 5a have also been shown to be recruited by the GHR. In addition, many transcripts are regulated independently of STAT5b as a result of GHR activation of Src, ERK, and PI3K-mTOR signaling pathways. The analysis of molecular mechanisms involved in inactivation of GHR-dependent signaling pathway is also imperative for understanding GH physiology. This is clearly illustrated in the case of hepatic GHR-JAK2-STAT5b activation where signal duration regulates gender differences in liver gene expression. An early step in the termination of GH-dependent signaling is removal of GHRs by endocytosis and ubiquitination. The level of ubiquitin ligase SOCS2 is constitutively low, but its expression is rapidly induced by GH. SOCS2 binding to GHR complex promotes their ubiquitination and subsequent proteasomal degradation, contributing to the termination of the GH intracellular signaling. Clinically relevant, SOCS2 is a key negative regulator of GH-dependent body growth and lipid and glucose homeostasis. Furthermore, several cytokines, growth factors, xenobiotics, and sex hormones can regulate SOCS2 protein level, which provides a mechanism for cross-talking where multiple factors can regulate GHR signaling during somatic development. A better understanding of this complex regulation in physiological and pathological states will contribute to prevent health damage and improve clinical management of patients with growth and metabolic disorders

Diodos orgánicos emisores de luz: estrategias para la optimización de dispositivos y la obtención de un oled blanco

III Encuentro sobre Nanociencia y Nanotecnología de Investigadores y Tecnólogos Andaluce