Efecto del peso inicial en el desarrollo sostenible de la producción de ganado vacuno en engorde intensivo a corral

The aim of this study was to conduct cultural energy (CE) analyses of beef cattle animals with different initial weights. Data were obtained by a questionnaire administered to 100 beef farms selected by stratified random sampling. The beef farms were divided into three groups based on initial animal weights and were analyzed. Initial weights were assigned as light (276 kg, 32 farms). Cultural energy used for feed for the treatments was derived from their lot feed consumption and values from the literature. Transportation energy was included in the analysis. As the objective of the study was to evaluate CE analysis of the feeding systems, energy that the calves had deposited in muscle and fat tissue, when they were purchased was deducted from carcass energy. Total expended CE was highest for the lighter animals (PEl propósito de este estudio fue realizar análisis de la energía para el engorde (CE) de ganado vacuno con diferentes pesos iniciales. Los datos se obtuvieron mediante un cuestionario dirigido a 100 granjas de vacuno seleccionadas por un método de muestreo estratificado y al azar. Las granjas fueron clasificadas en tres grupos, de acuerdo a los pesos iniciales, y analizadas. De acuerdo al peso inicial fueron agrupadas como ligeras ( 276 kg, 32 granjas). La energía utilizada para la alimentación en los tratamientos se obtuvo de los consumos correspondientes de cada uno de los lotes y de los valores de la bibliografía. La energía de transporte también se incluyó en el análisis. Puesto que el objetivo del estudio fue evaluar el análisis de CE de los sistemas de engorde, la energía que los terneros habían depositados en músculo y en tejido graso cuando fueron comprados se descontó de la energía de la canal. La CE total gastada fue superior para los más ligeros (

Absolute Dimensions and Apsidal Motion of the Young Detached System LT Canis Majoris

New high resolution spectra of the short period (P~1.76 days) young detached binary LT CMa are reported for the first time. By combining the results from the analysis of new radial velocity curves and published light curves, we determine values for the masses, radii and temperatures as follows: M_1= 5.59 (0.20) M_o, R_1=3.56 (0.07) R_o and T_eff1= 17000 (500) K for the primary and M_2=3.36 (0.14) M_o, R_2= 2.04 (0.05) R_o and T_eff2= 13140 (800) K for the secondary. Static absorbtion features apart from those coming from the close binary components are detected in the several spectral regions. If these absorbtion features are from a third star, as the light curve solutions support, its radial velocity is measured to be RV_3=70(8) km s^-1. The orbit of the binary system is proved to be eccentric (e=0.059) and thus the apsidal motion exists. The estimated linear advance in longitude of periastron corresponds to an apsidal motion of U=694+/-5 yr for the system. The average internal structure constant log k_2,obs=-2.53 of LT CMa is found smaller than its theoretical value of log k_2,theo=-2.22 suggesting the stars would have more central concentration in mass. The photometric distance of LT CMa (d=535+/-45 pc) is found to be much smaller than the distance of CMa OB1 association (1150 pc) which rules out membership. A comparison with current stellar evolution models for solar metallicity indicates that LT CMa (35 Myr) is much older than the CMa OB1 association (3 Myr), confirming that LT CMa is not a member of CMa OB1. The kinematical and dynamical analysis indicate LT CMa is orbiting the Galaxy in a circular orbit and belongs to the young thin-disk population.Comment: 19 pages, 6 figures and 6 tables, accepted for publication in Publication of the Astronomical Society of Japa

Generation of unipolar half-cycle pulse via unusual reflection of a single-cycle pulse from an optically thin metallic or dielectric layer

We present a significantly different reflection process from an optically thin flat metallic or dielectric layer and propose a strikingly simple method to form approximately unipolar half-cycle optical pulses via reflection of a single-cycle optical pulse. Unipolar pulses in reflection arise due to specifics of effectively one-dimensional pulse propagation. Namely, we show that in considered system the field emitted by a flat medium layer is proportional to the velocity of oscillating medium charges instead of their acceleration as it is usually the case. When the single-cycle pulse interacts with linear optical medium, the oscillation velocity of medium charges can be then forced to keep constant sign throughout the pulse duration. Our results essentially differ from the direct mirror reflection and suggest a possibility of unusual transformations of the few-cycle light pulses in linear optical systems

Study of Eclipsing Binary and Multiple Systems in OB Associations: I. Ori OB1a - IM Mon

All available photometric and spectroscopic observations were collected and used as the basis of a detailed analysis of the close binary IM Mon. The orbital period of the binary was refined to 1.19024249(0.00000014) days. The Roche equipotentials, fractional luminosities (in (B, V) and H_p bands) and fractional radii for the component stars in addition to mass ratio q, inclination i of the orbit and the effective temperature T_eff of the secondary cooler less massive component were obtained by the analysis of light curves. IM Mon is classified to be a detached binary system in contrast to the contact configuration estimations in the literature. The absolute parameters of IM Mon were derived by the simultaneous solutions of light and radial velocity curves as M_1,2=5.50(0.24)M_o and 3.32(0.16)M_o, R1,2=3.15(0.04)R_o and 2.36(0.03)R_o, T_eff1,2=17500(350) K and 14500(550) K implying spectral types of B4 and B6.5 ZAMS stars for the primary and secondary components respectively. The modelling of the high resolution spectrum revealed the rotational velocities of the component stars as V_rot1=147(15) km/s and V_rot2=90(25) km/s. The photometric distance of 353(59) pc was found more precise and reliable than Hipparcos distance of 341(85) pc. An evolutionary age of 11.5(1.5) Myr was obtained for IM Mon. Kinematical and dynamical analysis support the membership of the young thin-disk population system IM Mon to the Ori OB1a association dynamically. Finally, we derived the distance, age and metallicity information of Ori OB1a sub-group using the information of IM Mon parameters.Comment: 26 pages, 5 figures and 6 tables, accepted for publication in Publication of the Astronomical Society of Japa

Study of Eclipsing Binary and Multiple Systems in OB Associations II. The Cygnus OB Region: V443 Cyg, V456 Cyg and V2107 Cyg

Three presumably young eclipsing binary systems in the direction of the Cygnus OB1, OB3 and OB9 associations are studied. Component spectra are reconstructed and their orbits are determined using light curves and spectra disentangling techniques. V443 Cyg and V456 Cyg have circular orbits, while the light curve of V2107\,Cyg imposes a slightly eccentric orbit ($e=0.045\pm0.03)$. V443 Cyg harbours F-type stars, and not young early-A stars as previously suggested in the literature based on photometry solely. It appears to be situated in the foreground (distance $0.6\pm0.2$ kpc) of the young stellar populations in Cygnus. V456 Cyg, at a distance of $0.50\pm0.03$ kpc consists of a slightly metal-weak A--type and an early--F star. The age of both systems, on or very near to the main sequence, remains uncertain by an order of magnitude. V2107 Cyg is a more massive system ($8.9\pm2$ and $4.5\pm1.2 M_\odot$) at $1.5\pm0.5$ kpc and, also kinematically, a strong candidate-member of Cyg OB1. The more massive component is slightly evolved and appears to undergo non-radial $\beta Cep$-type pulsations. The Doppler signal of the secondary is barely detectable. A more extensive study is important to fix masses more precisely, and an asteroseismological study would then become appropriate. Nevertheless, the position of the primary in the HR-diagram confines the age already reasonably well to $20\pm5$ Myr, indicating for Cyg OB1 a similar extent of star formation history as established for Cyg OB2.Comment: 27 pages, including 9 figures and 6 tables, accepted for publication in Astronomical Journa

The Spectroscopic Orbits of Three Double-lined Eclipsing Binaries: I. BG Ind, IM Mon, RS Sgr

We present the spectroscopic orbit solutions of three double-lines eclipsing binaries, BG Ind, IM Mon and RS Sgr. The first precise radial velocities (RVs) of the components were determined using high resolution echelle spectra obtained at Mt. John University Observatory in New Zealand. The RVs of the components of BG Ind and RS Sgr were measured using Gaussian fittings to the selected spectral lines, whereas two-dimensional cross-correlation technique was preferred to determine the RVs of IM Mon since it has relatively short orbital period among the other targets and so blending of the lines is more effective. For all systems, the Keplerian orbital solution was used during the analysis and also circular orbit was adopted because the eccentricities for all targets were found to be negligible. The first precise orbit analysis of these systems gives the mass ratios of the systems as 0.894, 0.606 and 0.325, respectively for BG Ind, IM Mon and RS Sgr. Comparison of the mass ratio values, orbital sizes and minimum masses of the components of the systems indicates that all systems should have different physical, dynamical and probable evolutionary status.Comment: 17 pages, 6 figures and 4 tables, accepted for publication in New Astronom

On the orbital period of the magnetic Cataclysmic Variable HS 0922+1333

Context: The object HS 0922+1333 was visited briefly in 2002 in a mini survey of low accretion rate polars (LARPs) in order to test if they undergo high luminosity states similar to ordinary polars. On the basis of that short observation the suspicion arose that the object might be an asynchronous polar (Tovmassian et al. 2004). The disparity between the presumed orbital and spin period appeared to be quite unusual. Aims: We performed follow-up observations of the object to resolve the problem. Methods: New simultaneous spectroscopic and photometric observations spanning several years allowed measurements of radial velocities of emission and absorption lines from the secondary star and brightness variations due to synchrotron emission from the primary. Results: New observations show that the object is actually synchronous and its orbital and spin period are equal to 4.04 hours. Conclusions: We identify the source of confusion of previous observations to be a high velocity component of emission line arousing from the stream of matter leaving L1 point.Comment: 5 pages, 5 figures, accepted for publication in Astronomy & Astrophysic

All-optical attoclock: accessing exahertz dynamics of optical tunnelling through terahertz emission

The debate regarding attosecond dynamics of optical tunneling has so far been focused on time delays associated with electron motion through the potential barrier created by intense ionizing laser fields and the atomic core. Compelling theoretical and experimental arguments have been put forward to advocate the polar opposite views, confirming or refuting the presence of tunnelling time delays. Yet, such delay, whether present or ot, is but a single quantity characterizing the tunnelling wavepacket; the underlying dynamics are richer. Here we propose to complement photo-electron detection with detecting light, focusing on the so-called Brunel adiation -- the near-instantaneous nonlinear optical response triggered by the tunnelling event. Using the combination of single-color and two-color driving fields, we determine not only the ionization delays, but also the re-shaping of the tunnelling wavepacket as it emerges from the classically forbidden region. Our work introduces a new type of attoclock for optical tunnelling, one that is based on measuring light rather than photo-electrons. All-optical detection paves the way to time-resolving multiphoton transitions across bandgaps in solids, on the attosecond time-scale

Binary Bose-Einstein Condensate Mixtures in Weakly and Strongly Segregated Phases

We perform a mean-field study of the binary Bose-Einstein condensate mixtures as a function of the mutual repulsive interaction strength. In the phase segregated regime, we find that there are two distinct phases: the weakly segregated phase characterized by a `penetration depth' and the strongly segregated phase characterized by a healing length. In the weakly segregated phase the symmetry of the shape of each condensate will not take that of the trap because of the finite surface tension, but its total density profile still does. In the strongly segregated phase even the total density profile takes a different symmetry from that of the trap because of the mutual exclusion of the condensates. The lower critical condensate-atom number to observe the complete phase segregation is discussed. A comparison to recent experimental data suggests that the weakly segregated phase has been observed.Comment: minor change