Control del déficit energético y actividad ovárica de conejas primíparas sometidas a destete temprano

El objetivo de este estudio fue estudiar el efecto de un destete temprano, realizado a los 25 días post-parto (dpp), con el fin de reducir el déficit energético de las conejas primíparas y mejorar su eficacia reproductiva. Para ello, se estudió el efecto sobre las reservas corporales y la actividad ovárica de 34 conejas primíparas lactantes. Se sacrificó un grupo (n=10) a los 25 dpp (L25), otro (n=13) se destetó a los 25 dpp y se sacrificó a los 32 dpp (NL32) y un tercero (n=11), no se destetó y se sacrificó a los 32 dpp (L32). El peso vivo de los animales, las concentraciones de ácidos grasos no esterificados (AGNE) y de proteínas plasmáticas totales en el suero fueron similares en todos los grupos. Aunque el grupo NL32, después del destete, consumió menos alimento que el grupo L32 (122±23,5 vs. 402±26,7g/d, respectivamente; P < 0,001), sus contenidos estimados de lípidos (16,9±1,09%; P < 0,008), proteína (19,7±0,07%; P < 0,0001) y energía corporales (1147±42,7 MJ/kg; P < 0,006) fueron mayores, y sus concentraciones plasmáticas de glucosa (158±24,5mg/dl; P < 0,04) fueron menores que las del grupo L25 (11,9±1,3%, 18,5±0,08%, 942±51,3 MJ/kg y 212±27,9 mg/dl ) y que las del grupo L32, (13,4±1,03%, 18,5±0,1%, 993±40,4 MJ/kg and 259±29,5 mg/dl), respectivamente. El recuento de la población folicular en los ovarios fue similar en los tres grupos. La maduración nuclear (% de oocitos en metafase II) y la citoplásmica (% de gránulos corticales total o parcialmente migrados) fue significativamente menor en el grupo sacrificado a los 25 dpp (L25), que en los grupos NL32 y L32 (67 vs. 79,7 y 78,3%; P < 0,05; 16 vs. 38,3 y 60,0%; P<0,05, respectivamente). En conclusión, las reservas energéticas de la coneja primípara aumentan si es destetada a 25 dpp. Sin embargo, esta estrategia no es suficiente desde el punto de vista reproductivo, ya que a los 32 dpp, la actividad ovárica de las conejas es similar independientemente de si han sido destetadas previamente o no

Métodos de sincronización de celo en conejas primíparas lactantes a 25 días post-parto

La sincronización del celo es una técnica necesaria en las explotaciones cunícolas. En este trabajo se han utilizado un total de 60 conejas primíparas lactantes en día 25 post-parto (pp) distribuidas en 5 grupos de 12 animales: el grupo PG recibió un 2.5% de propilen glicol en el agua de bebida desde el día 22 pp, el grupo eCG se trató con 25 UI de eCG (i.m.) el día 23 pp, el grupo BIO fue separado transitoriamente de sus camadas durante 24 horas, el grupo PGBIO se suplementó con 2,5% de PG y además se le separó transitoriamente de su camada, y por último, el grupo C que no fue sincronizado. Estudiamos el efecto de estos tratamientos sobre el peso vivo, la composición corporal, el consumo de alimento, la concentración de los ácidos grasos no esterificados (AGNE), la glucosa y las proteínas plasmáticas, el crecimiento de los gazapos y la fisiología ovárica. Aunque todos los grupos tuvieron el mismo consumo de pienso, las conejas del grupo PG presentaron menos cantidad de proteína (P<0,003) y de grasa corporal (P<0,06) el día 25 pp que al principio del tratamiento. En los grupos PG y PGBIO, las concentraciones de AGNE no se modificaron y las concentraciones de proteínas plasmáticas eran más altas el día 22 que el 25 pp. En todos los grupos las concentraciones de glucosa aumentaron (P<0,001) y las camadas crecieron significativamente (P<0,001). Las poblaciones foliculares ováricas en el día 25 pp, así como la maduración nuclear in vitro de los oocitos no se vieron afectadas por ningún tratamiento. El grupo PG presentó una baja proporción de oocitos no madurados citoplásmicamente (P<0,05). En conclusión, ninguno de los tratamientos aplicados, incluido el hormonal, ha presentado resultados definitivamente mejores que el grupo control, por lo que es necesario estudiar otras combinaciones o métodos para poder conseguir mejorar sustancialmente los parámetros reproductivos en conejas primíparas lactantes en el día 25 pp

Respuesta hipofisaria y ovulatoria de conejas nulíparas alimentadas con dietas suplementadas con ácidos grasos poliinsaturados n-3

Twenty rabbit does were fed ad libitum from 10 to 16 weeks of age two isofibrous, isoenergetic and isoproteic diets (n=10) supplemented with two different fat sources: 0.75% lard for diet C (control) or 1.5% of a supplement (Optomega-50; Optivite International Ltd., Spain) containing a 50% of EE and 38% of n-3 polyunsaturated fatty acids for diet P (PUFA n-3). Does feed intake, ovulation rate and plasma progesterone and LH concentrations at 0, 60 min, 5, 7 and 9 days post-induction of ovulation with 20 μg of Gonadorelina (Inducel-GnRH, Lab. Ovejero) at 16 weeks of age were assessed. Average daily intake (150.5 g/d), ovulation rate (95%), preovulatory peak of plasma LH (149.7±10.9 ng/ml ng/ml) and number of corpora lutea (9.8±0.7) were similar between dietary treatments. Plasma progesterone concentrations increased at 60 minutes (7.13±1.9 ng/ml) and 5 days (13.3±1.9 ng/ml) after induction with respect to day 0 (0.7±1.9 ng/ml; P<0.05), remaining constant afterward in both groups (19.4±1.9 ng/ml). Moreover, plasma progesterone of does fed diet P tended to be higher than for diet C on day 5 and 7 post-induction (16.6±1.9 vs.12.6±1.8 and 19.0±1.8 vs. 15.5±2.1 ng/ml, P=0.068 and P=0.082; respectively). Therefore, PUFA n-3 supplementation in does rabbit diets might be related with high progesterone levels and reduced early embryo mortality.Veinte conejas nulíparas se alimentaron ad libitum desde las 10 a las 16 semanas de edad con dos piensos isofibrosos, isoenergéticos e isoproteicos suplementados con dos fuentes de grasa diferentes: 0,75% de manteca para la dieta control (grupo C; n=10) ó 1,5% de un suplemento (Optomega-50; Optivite International Ltd., España) que contenía un 50% de extracto etérero y 38% de ácidos grasos poli-insaturados n-3 (AG n-3) para la dieta experimental (grupo P; n=10). A las 16 semanas de edad se determinó el consumo de pienso, así como la tasa de ovulación y las concentraciones plasmáticas de progesterona y LH a 0, 60 min, 5, 7 y 9 días post-inducción de ovulación con 20 μg de Gonadorelina (Inducel-GnRH, Lab. Ovejero). El consumo de pienso (150,5 g/d), el pico preovulatorio de LH (149,7±10,9 ng/ml), la tasa de ovulación (95%) y el número de cuerpos lúteos (9,8±0,7) fueron similares entre tratamientos. Las concentraciones plasmáticas de progesterona aumentaron a los 60 minutos (7,13±19 ng/ml) y 5 días (13,3±1,9 ng/ml) con respecto al día 0 (0,7±1,9 ng/ml; P<0.05), permaneciendo elevadas el día 9 en ambos grupos (19,4±1,9 ng/ml). Además, el día 5 y 7 post-inducción, las hembras alimentadas con la dieta P tendieron a tener niveles más elevados de progesterona en sangre que las alimentadas con la dieta C (16,6±1,9 vs.12,6±1,8 y 19,0±1,8 vs. 15,5±2,1 ng/ml, P=0,068 y P=0,082; respectivamente) que coinciden con el momento de la implantación embrionaria en esta especie. Por lo tanto, la suplementación con AG n-3 podría mejorar los niveles de progesterona en sangre y por lo tanto reducir la mortalidad embrionaria en este punto

Acceleration Schemes for Ab-Initio Molecular Dynamics and Electronic Structure Calculations

We study the convergence and the stability of fictitious dynamical methods for electrons. First, we show that a particular damped second-order dynamics has a much faster rate of convergence to the ground-state than first-order steepest descent algorithms while retaining their numerical cost per time step. Our damped dynamics has efficiency comparable to that of conjugate gradient methods in typical electronic minimization problems. Then, we analyse the factors that limit the size of the integration time step in approaches based on plane-wave expansions. The maximum allowed time step is dictated by the highest frequency components of the fictitious electronic dynamics. These can result either from the large wavevector components of the kinetic energy or from the small wavevector components of the Coulomb potential giving rise to the so called {\it charge sloshing} problem. We show how to eliminate large wavevector instabilities by adopting a preconditioning scheme that is implemented here for the first-time in the context of Car-Parrinello ab-initio molecular dynamics simulations of the ionic motion. We also show how to solve the charge-sloshing problem when this is present. We substantiate our theoretical analysis with numerical tests on a number of different silicon and carbon systems having both insulating and metallic character.Comment: RevTex, 9 figures available upon request, to appear in Phys. Rev.

Fertilidad, desarrollo embrionario y prolificidad de conejas nulíparas alimentadas con piensos enriquecidos en ácidos grasos poliinsaturados n-3

One hundred and five nulliparous rabbit does were fed ad libitum one month before and during pregnancy with two isofibrous, isoenergetic and isoproteic diets supplemented with two different fat sources: 0.75% lard for control diet (C group: n=53) or 1.5% of a supplement (Optomega-50; Optivite International Ltd., España) containing a 50% of ether extract and 38% of n-3 polyunsaturated fatty acids (PUFA) for experimental diet (group P n-3; n=52). Fertility after artificial insemination and induction of ovulation with 20 μg of Gonadorelina (Inducel-GnRH, Ovejero) at 4.5 months of age was assessed. At parturition, pregnancy length and prolificacy (number and weight of born alive and number of stillborn) were observed. A total of 8 pregnant does from each experimental group were chosen at random to study embryo and placenta dimensions by means of ultrasonography at 8, 15 and 22 days of pregnancy. PUFA n-3 supplementation did not affect any productive results due the success on reproductive features of nulliparous does which are difficult to improve. Neither, any differences in ultrasonographic meausrements were obtained; nevertheless we have defined useful physiological parameters of rabbit embryo and placenta to future studies in this specie.Un total de 105 conejas nulíparas se alimentaron ad libitum un mes antes y durante su primera gestación con dos piensos isofibrosos, isoenergéticos e isoproteicos suplementados con dos fuentes de grasa diferentes: 0,75% de manteca para la dieta control (grupo C; n=53) ó 1,5% de un suplemento (Optomega-50; Optivite International Ltd., España) que contenía un 50% de extracto etéreo y 38% de ácidos grasos poli-insaturados (AG n-3) para la dieta experimental (grupo P; n=52). A los 4,5 meses de edad se determinó la fertilidad después de ser inseminadas artificialmente y tratadas con 20 μg de Gonadorelina (Inducel-GnRH, Ovejero) para inducirles la ovulación. Al parto se determinó la duración de la gestación, el número y peso de los gazapos nacidos vivos y muertos. Se escogieron 16 conejas al azar, 8 de cada grupo, y se realizaron ecografías a los 8, 15 y 22 días de gestación en las que se determinó las dimensiones del embrión y de los anejos fetales. La suplementación con AG n-3 no afectó a los resultados productivos determinados ya que se trata de parámetros que en nulíparas son difíciles de mejorar y suelen ser altos. Tampoco se observaron diferencias en las determinaciones ecográficas pero se han podido definir medidas fisiológicas de los fetos y anejos placentarios de gran utilidad para futuros estudios en esta especie

The Covariant Entropy Bound, Brane Cosmology, and the Null Energy Condition

In discussions of Bousso's Covariant Entropy Bound, the Null Energy Condition is always assumed, as a sufficient {\em but not necessary} condition which helps to ensure that the entropy on any lightsheet shall necessarily be finite. The spectacular failure of the Strong Energy Condition in cosmology has, however, led many astrophysicists and cosmologists to consider models of dark energy which violate {\em all} of the energy conditions, and indeed the current data do not completely rule out such models. The NEC also has a questionable status in brane cosmology: it is probably necessary to violate the NEC in the bulk in order to obtain a "self-tuning" theory of the cosmological constant. In order to investigate these proposals, we modify the Karch-Randall model by introducing NEC-violating matter into $AdS_5$ in such a way that the brane cosmological constant relaxes to zero. The entropy on lightsheets remains finite. However, we still find that the spacetime is fundamentally incompatible with the Covariant Entropy Bound machinery, in the sense that it fails the Bousso-Randall consistency condition. We argue that holography probably forbids all {\em cosmological} violations of the NEC, and that holography is in fact the fundamental physical principle underlying the cosmological version of the NEC.Comment: 21 pages, 3 figures, version 2:corrected and greatly improved discussion of the Bousso-Randall consistency check, references added; version3: more references added, JHEP versio

Conformally flat spacetimes and Weyl frames

We discuss the concepts of Weyl and Riemann frames in the context of metric theories of gravity and state the fact that they are completely equivalent as far as geodesic motion is concerned. We apply this result to conformally flat spacetimes and show that a new picture arises when a Riemannian spacetime is taken by means of geometrical gauge transformations into a Minkowskian flat spacetime. We find out that in the Weyl frame gravity is described by a scalar field. We give some examples of how conformally flat spacetime configurations look when viewed from the standpoint of a Weyl frame. We show that in the non-relativistic and weak field regime the Weyl scalar field may be identified with the Newtonian gravitational potential. We suggest an equation for the scalar field by varying the Einstein-Hilbert action restricted to the class of conformally-flat spacetimes. We revisit Einstein and Fokker's interpretation of Nordstr\"om scalar gravity theory and draw an analogy between this approach and the Weyl gauge formalism. We briefly take a look at two-dimensional gravity as viewed in the Weyl frame and address the question of quantizing a conformally flat spacetime by going to the Weyl frame.Comment: LATEX - 18 page

China-United States Research Collaborations in Antimicrobial Resistance

A strong synergy can result from China-US antimicrobial resistance (AMR) collaborations given similarities and differences between their respective healthcare systems and research infrastructures. The Antibacterial Resistance Leadership Group has employed a model of realistic growth, starting with a feasible, relatively low-resource observational study in a critical priority pathogen. This and other observational studies will provide vital scientific information required for the rational design of future interventional trials. In addition, it provides a mutual, low-risk opportunity for determining the strengths and opportunities of the research collaboration. Issues identified during the observational studies can be addressed prior to the initiation of high-resource interventional studies. Collaborative clinical AMR studies between China and the United States have tremendous potential to decrease AMR rates, improve responsible antibiotic use, and ultimately improve the lives of patients in both countries

High prognostic value of measurable residual disease detection by flow cytometry in chronic lymphocytic leukemia patients treated with front-line fludarabine, cyclophosphamide, and rituximab, followed by three years of rituximab maintenance

It has been postulated that monitoring measurable residual disease (MRD) could be used as a surrogate marker of progression-free survival (PFS) in chronic lymphocytic leukemia (CLL) patients after treatment with immunochemotherapy regimens. In this study, we analyzed the outcome of 84 patients at 3 years of follow-up after first-line treatment with fludarabine, cyclophosphamide and rituximab (FCR) induction followed by 36 months of rituximab maintenance thearpy. MRD was assessed by a quantitative four-color flow cytometry panel with a sensitivity level of 10-4. Eighty out of 84 evaluable patients (95.2%) achieved at least a partial response or better at the end of induction. After clinical evaluation, 74 patients went into rituximab maintenance and the primary endpoint was assessed in the final analysis at 3 years of follow-up. Bone marrow (BM) MRD analysis was performed after the last planned induction course and every 6 months in cases with detectable residual disease during the 36 months of maintenance therapy. Thirty-seven patients (44%) did not have detectable residual disease in the BM prior to maintenance therapy. Interestingly, 29 patients with detectable residual disease in the BM after induction no longer had detectable disease in the BM following maintenance therapy. After a median followup of 6.30 years, the median overall survival (OS) and PFS had not been reached in patients with either undetectable or detectable residual disease in the BM, who had achieved a complete response at the time of starting maintenance therapy. Interestingly, univariate analysis showed that after rituximab maintenance OS was not affected by IGHV status (mutated vs. unmutated OS: 85.7% alive at 7.2 years vs. 79.6% alive at 7.3 years, respectively). As per protocol, 15 patients (17.8%), who achieved a complete response and undetectable peripheral blood and BM residual disease after four courses of induction, were allowed to stop fludarabine and cyclophosphamide and complete two additional courses of rituximab and continue with maintenance therapy for 18 cycles. Surprisingly, the outcome in this population was similar to that observed in patients who received the full six cycles of the induction regimen. These data show that, compared to historic controls, patients treated with FCR followed by rituximab maintenance have high-quality responses with fewer relapses and improved OS. The tolerability of this regime is favorable. Furthermore, attaining an early undetectable residual disease status could shorten the duration of chemoimmunotherapy, reducing toxicities and preventing long-term side effects. The analysis of BM MRD after fludarabine-based induction could be a powerful predictor of post-maintenance outcomes in patients with CLL undergoing rituximab maintenance and could be a valuable tool to identify patients at high risk of relapse, influencing further treatment strategies

Permanent Genetic Resources added to Molecular Ecology Resources Database 1 February 2013-31 March 2013

This article documents the addition of 142 microsatellite marker loci to the Molecular Ecology Resources database. Loci were developed for the following species: Agriophyllum squarrosum, Amazilia cyanocephala, Batillaria attramentaria, Fungal strain CTeY1 (Ascomycota), Gadopsis marmoratus, Juniperus phoenicea subsp. turbinata, Liriomyza sativae, Lupinus polyphyllus, Metschnikowia reukaufii, Puccinia striiformis and Xylocopa grisescens. These loci were cross-tested on the following species: Amazilia beryllina, Amazilia candida, Amazilia rutila, Amazilia tzacatl, Amazilia violiceps, Amazilia yucatanensis, Campylopterus curvipennis, Cynanthus sordidus, Hylocharis leucotis, Juniperus brevifolia, Juniperus cedrus, Juniperus osteosperma, Juniperus oxycedrus, Juniperus thurifera, Liriomyza bryoniae, Liriomyza chinensis, Liriomyza huidobrensis and Liriomyza trifolii. © 2013 John Wiley & Sons Ltd.Peer Reviewe