Theory of Bubble Nucleation and Cooperativity in DNA Melting

The onset of intermediate states (denaturation bubbles) and their role during the melting transition of DNA are studied using the Peyrard-Bishop-Daxuois model by Monte Carlo simulations with no adjustable parameters. Comparison is made with previously published experimental results finding excellent agreement. Melting curves, critical DNA segment length for stability of bubbles and the possibility of a two states transition are studied.Comment: 4 figures. Accepted for publication in Physical Review Letter

SiGe quantum dots for fast hole spin Rabi oscillations

We report on hole g-factor measurements in three terminal SiGe self-assembled quantum dot devices with a top gate electrode positioned very close to the nanostructure. Measurements of both the perpendicular as well as the parallel g-factor reveal significant changes for a small modulation of the top gate voltage. From the observed modulations we estimate that, for realistic experimental conditions, hole spins can be electrically manipulated with Rabi frequencies in the order of 100MHz. This work emphasises the potential of hole-based nano-devices for efficient spin manipulation by means of the g-tensor modulation technique

Thermodynamics of Extended Bodies in Special Relativity

Relativistic thermodynamics is generalized to accommodate four dimensional rotation in a flat spacetime. An extended body can be in equilibrium when its each element moves along a Killing flow. There are three types of basic Killing flows in a flat spacetime, each of which corresponds to translational motion, spatial rotation, and constant linear acceleration; spatial rotation and constant linear acceleration are regarded as four dimensional rotation. Translational motion has been mainly investigated in the past literature of relativistic thermodynamics. Thermodynamics of the other two is derived in the present paper.Comment: 8 pages, no figur

Measuring carbon nanotube vibrations using a single-electron transistor as a fast linear amplifier

We demonstrate sensitive and fast electrical measurements of a carbon nanotube mechanical resonator. The nanotube is configured as a single-electron transistor, whose conductance is a sensitive transducer for its own displacement. Using an impedance-matching circuit followed by a cryogenic amplifier, the vibrations can be monitored in real time. The sensitivity of this continuous displacement measurement approaches within a factor 470 of the standard quantum limit.Comment: 10 pages, 6 figures; Published versio

Echolucency of carotid plaques correlates with plaque cellularity

AbstractObjective: to analyse the relationship between carotid plaque echolucency and cellularity. Methods: carotid plaques (14 symptomatic and 16 asymptomatic) were snap frozen after endarterectomy and defined on the basis of their grey-scale-median (GSM), obtained from pre-operative high-definition ultrasonography, as either echolucent (<32) or echogenic (≥32). DNA and total soluble protein were determined to assess cellularity. Results: after correcting for wet weight, symptomatic plaques had significantly more DNA (0.400 ± 0.07 vs 0.335 ± 0.07 mg/g; p = 0.03) and soluble protein (34.1 ± 6.6 vs 29.7 ± 3.4 mg/g; p = 0.03) than asymptomatic plaques. Predominantly echolucent (Grey-Weale classification) plaques had more DNA (0.404 ± 0.06 vs 0.332 ± 0.08 mg/g; p = 0.03) than echogenic plaques. Plaques with GSM < 32 also had more DNA (0.386 ± 0.08 vs 0.319 ± 0.06 mg/g; p = 0.04) and soluble protein (34.7 ± 7.3 vs 29.6 ± 4.2 mg/g; p = 0.03) than those with GSM ≥ 32. Inverse relations were found between GSM and plaque DNA (r = −0.47; p = 0.02) and soluble protein (r = −0.45; p = 0.02) as well as between age and DNA (r = 0.39; p = 0.04) and soluble protein (r = −0.50; p = 0.003). Conclusions: echolucency of carotid plaques as assessed by ultrasonography reflects plaque cellularity. This observation support the notion that ultrasonography can be used to identify high-risk plaques and evaluate effect of interventions on plaque structure.Eur J Vasc Endovasc Surg 26, 32-38 (2003

Relationships between site factors and the growth of conifers introduced in Ventania (Province of Buenos Aires), Argentina

Se evaluó la influencia de factores de sitio sobre el crecimiento de 22 rodales de pino de Alepo (Plnus halepensis MUI), 20 de pino de Monterrey (Plnus radiata D.Don.), 15 de cedro del Himalaya (Cedrus deociara (Roxb) Loudon) y 15 de ciprés horizontal (Cupressus sempervirens i. horizontal (Mid.) Voos), ubicados en una vasta área del sistema serrano de Ventania. Las variables edáficas correlacionadas con el índice de sitio como indicador del crecimiento, fueron: profundidad deenraizamiento y pedregosldad a 0-30 y 30-60 cm de profundidad en P. halepensis; pedregosidad y contenidos de gravas finas y gravillas, y de arena en C. deodara, y profundidad de enraizamiento y color (value) del horizonte A en C. sempervirens. Ningún factor edáfico se correlacionó significativamente con el crecimiento de P. radiata. Los modelos de regresión utilizando únicamente aspectos edáficos permitieron explicar entre 23 y 70% de la variabilidad en el índice de sitio. Entre las variables geográficas, topográficas y climáticas se encontraron correlacionadas con el creci­miento de las distintas especies: latitud, longitud, altitud, longitud e inclinación de la pendiente, posición en el relieve, precipitación, suma anual de déficits y superávits hídricos, temperatura media del mes más cálido y otras variables climáticas, las que tuvieron particular incidencia en P. radiata. Incluyendo todas las variables ambientales en forma conjunta, la explicación de la varianza del índicede sitio se elevó a 60-85% según la especie.It was studied the influence of site factors on growth of stands of Aleppo pine (Plnus halepensis. Mill.), 20 stands of Monterey pine (Pinos radiate D. Don.), 15 stands of deodar cedar (Cedros deodara (Roxb) Loudon) and 15 stands of itaiian or common cypress (Cupressus sempervirens f. horizontalis (Mill.) Voos), located in a large area of the hilly system of Ventania Soil variables correlated with site index as growth estimator were: depth of rooting and stoniness at a depth of 0-30 and 30-60 cm for P. halepensis, stoniness, and gravel and sand content for C. deodara and depth of rooting and cotor (value) of A horizon for C. sempervirens. No soil factor was significantly correlated with the growth of P. radiate. Regression models including soil variables explained between 23 and 70% of foe variation in site index. Growth of the studied species was correlated with foe following geographic, topographic and climatic variables: latitude, longitude, altitude, slope length and gradient, slope position, rainfall, annual sum of water deficits and surpluses, mean temperature of the warmest month and other climatic variables which mainly affected growth of P. radiata. Including all the environmental variables, the explanation of the variation in site index grew up to 60-85%.Facultad de Ciencias Agrarias y Forestale

Influence of the context in the quality of the clinical interview in physiotherapy

[Resumen] La calidad es un tema que está de actualidad no sólo en su vertiente científico técnica, sino también en el aspecto de las relaciones humanas. Si bien es un asunto muy abordado en varias profesiones sanitarias, pocos estudios se han realizado en este sentido en el ámbito de la Fisioterapia. Sin embargo, se ha encontrado que la relación del fisioterapeuta con el paciente es susceptible de mejora. Dicha relación se inicia en la entrevista clínica y ésta a su vez está enmarcada en un contexto o entorno que debe ser favorable para su desarrollo. Dentro del contexto se ha de prestar atención a la imagen del profesional, proxémica o distribución del espacio, lenguaje corporal (gestos y posturas) y componentes paralingüísticos. Se persigue con la atención a los componentes enunciados la facilitación de la comunicación y con ello una mejora en la entrevista clínica.[Abstract] The quality of medical care has been given increased attention in recent years, not only in its scientific and technical version but in the human relationships. Doctors have focused on the latter aspect but few studies have been done in this area about physiotherapists communications and relationships. The results point out that communications and relationships between physiotherapists and patients can be improved. This relationship begins in the clinical interview which is framed in a context or environment That has to be favourable for its development. Inside the context it is necessary to pay attention to the professional image, room distribution, body language and paralinguistic. The aim of the focus on these components is to make easier the clinical interview, and finally an improvement of the clinical interview

Collective modes of coupled phase oscillators with delayed coupling

We study the effects of delayed coupling on timing and pattern formation in spatially extended systems of dynamic oscillators. Starting from a discrete lattice of coupled oscillators, we derive a generic continuum theory for collective modes of long wavelength. We use this approach to study spatial phase profiles of cellular oscillators in the segmentation clock, a dynamic patterning system of vertebrate embryos. Collective wave patterns result from the interplay of coupling delays and moving boundary conditions. We show that the phase profiles of collective modes depend on coupling delays.Comment: 5 pages, 2 figure