Medidas de eficiencia en la producción de leche: el caso de la provincia de Córdoba

En la presente investigacion se pretende buscar la mejor relacion entre costes, ingresos e inversion que de el mayor margen y rentabilidad a las explotaciones lecheras de Cordoba. Se toma la informacion recogida de 38 explotaciones lecheras, por el Centro de Investigacion y Formacion Agraria de Cordoba (CIFA-Cordoba), dentro del marco del proyecto INIA SC96-103. Como primer paso en la busqueda de esta mayor rentabilidad se empieza por evaluar sus eficiencias tecnicas en la produccion de leche considerando los inputs relevantes del sistema: alimentacion, coste de mano de obra, coste de amortizacion de equipos e instalaciones. Un ultimo analisis estima la eficiencia global de cada explotacion en terminos de rentabilidad considerando margenes y capitales invertidos. Todas estas medidas se realiza aplicando la metodologia DEA(Analisis Envolvente de Datos) estudiandose las principales causas o factores de ineficiencia y proponiendo mejoras concretas para optimizar el sistema, considerando las explotaciones de mejores practicas. Los resultados demuestran que la alimentacion es la variable que mas pesa en la eficiencia global del sistema, siendo el exceso de forraje aportado a la racion la principal causa de ineficienca. Para el grupo analizado, se estima su nivel optimo de asignacion por litro de lelche entre 0,44 y 0,59 kg de MS de concentrados y entre 0,12 y 0,24 kg de MS de forrajes (los valores actuales en terminos medios estan en 0,63 kg MS de concentrados y 0,48 kg MS de forrajes). Las variables de mano de obra y coste de amortizacion no resultaron motivo importante de ineficiencia, con pocas diferencia por litro entre explotaciones. Se alcanzaria una mayor rentabilidad y margen de explotacion aumentando la productividad a un minimo de 7600 litros/vaca en el grupo de estudio, logrando asi una mayor eficiencia de uso de factores y la reduccion consecuente de los costes unitarios de produccion. Las explotaciones eficientes del grupo analizado muestran que la rentabilidad marginal podria ir del 140% en las de menor escala al 10%, ajustandose al principio de rendimientos decrecientes

Native breeds conservation, sustainable economies and usefulness

In the present essay it is sought to tackle, from the point of view of Economic Methodology, questions so like: Must native breeds be preserved?. As soon as this question is resolved, assigning and appraising its importance, is the question. What values are derived from the native breeds existence?: Value by the obtained profit of its current consumption; Option value; Cuasi-option value. What appraisal techniques must be utilized?: Native breeds are considered like a flow resource; its services will be released in the future if a determined stock level is maintained, through the autoreproduction. Irreversibility and option values. The traditional economic analysis use to assume that decisions about resources use are reversible. That is, depending on avaible information, an agent makes an utilization plan of a renovable resource like the native breed, for today and for the future. Now, it is assumed that a new information (scientific and technological advance) appears in the future, and as a result of that, the optimal program of a resource use must be changed. If the taken decisions in the T period were reversible, it is accepted the agent could change the way of using this resource if the optimization process requires it. Is there a real extinction danger of a private renovable resource? The extinction danger of a renovable resource (native breed), independently and although it is in private hands, public hands or it is free, is originated from a serie of economic and market factors.En el presente ensayo se pretende abordar, desde el punto de vista de la metodología económica, la cuestión de si se deben conservar las razas autóctonas. Una vez que se resuelve esta pregunta se deben establecer los valores derivados de la existencia de las razas autóctonas: Valor por la utilidad obtenida de su actual consumo; Valor de la opción; Valor cuasi-opción. ¿Qúe técnicas de valoración se han de utilizar?. Se consideran las razas autóctonas como un recurso flujo; es decir cuyos servicios se liberarán en el futuro si se mantiene un nivel de stock determinado, a través de la autorreproducción. Irreversibilidad y valores de opción. El análisis económico convencional asume normalmente que las decisiones sobre utilización de recursos son reversibles. Es decir, que según la información disponible un agente hace un plan de utilización de un recurso renovable como la raza autóctona, para hoy y para el futuro. Ahora asumimos que en el futuro aparece un nueva información (avance científico y tecnológico) y que como consecuencia el programa óptimo de utilización de un recurso debe cambiar. Si las decisiones tomadas en el periodo T fuesen reversibles estamos aceptando que el agente podría cambiar el modo de usar este recurso si lo exige el proceso de optimización. ¿Existe un peligro real de extinción de un recurso renovable privado?. El peligro de extinción de un recurso renovable (raza autóctona) independientemente y aunque esté en manos privadas, públicas o se tenga libre acceso al mismo, nace en base a una serie de factores económicos y de mercado

A Dust-Penetrated Classification Scheme for Bars as Inferred from their Gravitational Force Fields

The division of galaxies into ``barred'' (SB) and ``normal'' (S) spirals is a fundamental aspect of the Hubble galaxy classification system. This ``tuning fork'' view was revised by de Vaucouleurs, whose classification volume recognized apparent ``bar strength'' (SA, SAB, SB) as a continuous property of galaxies called the ``family''. However, the SA, SAB, and SB families are purely visual judgments that can have little bearing on the actual bar strength in a given galaxy. Until very recently, published bar judgments were based exclusively on blue light images, where internal extinction or star formation can either mask a bar completely or give the false impression of a bar in a nonbarred galaxy. Near-infrared camera arrays, which principally trace the old stellar populations in both normal and barred galaxies, now facilitate a quantification of bar strength in terms of their gravitational potentials and force fields. In this paper, we show that the maximum value, Qb, of the ratio of the tangential force to the mean radial force is a quantitative measure of the strength of a bar. Qb does not measure bar ellipticity or bar shape, but rather depends on the actual forcing due to the bar embedded in its disk. We show that a wide range of true bar strengths characterizes the category ``SB'', while de Vaucouleurs category ``SAB'' corresponds to a much narrower range of bar strengths. We present Qb values for 36 galaxies, and we incorporate our bar classes into a dust-penetrated classification system for spiral galaxies.Comment: Accepted for publication in the Astrophysical Journal (LaTex, 30 pages + 3 figures); Figs. 1 and 3 are in color and are also available at http://bama.ua.edu/~rbuta/bars

Two-Sided Derivatives for Regular Expressions and for Hairpin Expressions

The aim of this paper is to design the polynomial construction of a finite recognizer for hairpin completions of regular languages. This is achieved by considering completions as new expression operators and by applying derivation techniques to the associated extended expressions called hairpin expressions. More precisely, we extend partial derivation of regular expressions to two-sided partial derivation of hairpin expressions and we show how to deduce a recognizer for a hairpin expression from its two-sided derived term automaton, providing an alternative proof of the fact that hairpin completions of regular languages are linear context-free.Comment: 28 page

An economic valuation of the horse production and utilization in Andalucia (Spain)

The Tourism and Sport Department of the Andalusian Government agreed to the University of Córdoba (Spain) an economic analysis of all the equestrian activities developed in Andalucía in 2002. It was sought to establish some axes of strategic behavior for the sector. With this idea, the general objectives of the work are planned: to analyze the total production generated by each activity developed in Andalucía in 2002, in which the horse is the main element of operation. The work begins with the definition of each activity and the executioner establishments. Once activites are defined, the economic valuation is realized by analyzing their costs of organization and participation. These results are aggregated and ordered in input-output tables for economic valuation of the total production generated by the sector in Andalucía. The results show that, in 2002, this sector produced 478 million of euros of which 320 millions proceeded from productive and selection activities of horses; 50 millions from sport activities; 31.3 millions from activities of leisure; 15 millions of recreational activities with participation and 26.4 millions were specific from the World Equestrian Games.La Consejería de Turismo y Deportes de la Junta de Andalucía convino con la Universidad de Córdoba un análisis de todas las actividades relacionadas con el caballo desarrolladas en Andalucía en el 2002. Con este fin se planean los objetivos generales del trabajo: analizar la producción total generada por cada una de las actividades desarrolladas en Andalucía en el 2002, en las que el caballo es el elemento esencial para su ejecución. El trabajo comienza con la definición de cada una de las actividades y los establecimientos operadores de aquellas. La valoración económica se realiza a partir del análisis de sus costes de organización y participación. Estos resultados se agregan y ordenan en tablas input-output para obtener la valoración económica de la producción total generada por el sector del caballo en Andalucía. Los resultados demuestran que, en 2002, este sector aportó a la producción bruta andaluza 478 millones de euros de los cuales 320 fueron de actividades productivas y selectivas de ganado; 50 de actividades deportivas; 31,3 de actividades de ocio contemplativo; 15 de actividades recreativas participativas y 26,4 específicos del encuentro de Jerez 2002

Increased toxin expression in a Clostridium difficile mfd mutant

BACKGROUND: The symptoms of Clostridium difficile infection are mediated primarily by two toxins, TcdA and TcdB, the expression of which is governed by a multitude of factors including nutrient availability, growth phase and cell stress. Several global regulators have been implicated in the regulation of toxin expression, such as CcpA and CodY. RESULTS: During attempts to insertionally inactivate a putative secondary cell wall polysaccharide synthesis gene, we obtained several mutants containing off-target insertions. One mutant displayed an unusual branched colony morphology and was investigated further. Marker recovery revealed an insertion in mfd, a gene encoding a transcription-coupled repair factor. The mfd mutant exhibited pleiotropic effects, in particular increased expression of both toxin A and B (TcdA and TcdB) compared to the parental strain. Western blotting and cellular cytotoxicity assays revealed increased expression across all time points over a 24 h period, with inactivation of mfd resulting in at least a 10 fold increase in cell cytotoxicity. qRT-PCR demonstrated the upregulation of both toxins occurred on a transcriptional level. All effects of the mfd mutation were complemented by a plasmid-encoded copy of mfd, showing the effects are not due to polar effects of the intron insertion or to second site mutations. CONCLUSIONS: This study adds Mfd to the repertoire of factors involved in regulation of toxin expression in Clostridium difficile. Mfd is known to remove RNA polymerase molecules from transcriptional sites where it has stalled due to repressor action, preventing transcriptional read through. The consistently high levels of toxin in the C. difficile mfd mutant indicate this process is inefficient leading to transcriptional de-repression

Process intensification for the production of cyclic macrolactones: identification of safe operating conditions in tubular reactors

In this work, the possibility to shift from a batch to a continuous production of 16-hexadecanolide, one of the main components of the white musk essence, was theoretically studied. The selected synthesis was an upgraded version of that proposed by Story in 1968, who obtained macrocyclic compounds from the decomposition of ketone peroxides (in this case the involved peroxide was tricyclohexylidene triperoxide). But such reaction presents some huge criticalities: 1) high exothermicity and, 2) production of carbon dioxide, which are known to both modify the kinetics of the desired reaction and lead to a pressure increase inside the reactor whether the gases are not vented. For such reasons, to implement any safe continuous production of this chemical compound, two main points must be addressed: 1) determination of the system runaway boundaries and 2) identification of the optimal operating conditions to make sustainable the production of 16-hexadecanolide (that is, the theoretical design of a tubular reactor capable of continuously discharging the produced incoercible gases). For what concerns the first point, a sensitivity analysis was carried out to determine the safe operating range of the most important operating variables (that is, coolant temperature and reactant inlet temperature) possibly taking into account the effect of radial dispersion; for the second point, as carbon dioxide is produced over the decomposition and needs to be continuously vented to avoid reactor pressurization, a Teflon tube, highly permeable with respect to carbon dioxide, was proposed and its theoretical performances was investigated trying to maximize 16-hexadecanolide productivity also maintaining safe operating conditions. Results showed the theoretical possibility of developing a continuous production process capable of being also commercially sustainable

Expression of p53 Protein and Tumor Angiogenesis as Prognostic Factors in Nasopharyngeal Carcinoma Patients.

The objective of this study was to evaluate the possible prognostic significance of p53 protein overexpression and tumor angiogenesis (TA) in nasopharyngeal carcinoma (NPC) patients, together with other clinicopathological variables. Forty-two NPC patients were evaluated in relation to survival. Nuclear p53 overexpression in neoplastic and endothelial cells was detected by immunohistochemistry (IHC) with the monoclonal antibody DO-7 and the polyclonal antibody against factor VIII-related antigen, respectively. Thereafter, we evaluated p53 cases in order to determine their nuclear immunoreactivity from negative (-) to positive (+, ++, +++). In addition, microvessels were counted in the most active areas of tumor neovascularization or hotspots using an image computer analyzer (MicroImage®). A Cox multiple regression survival analysis was used to determine the best prognostic indicators in NPC patients. As a result, tumor microvessel count, considered as a continuous variable, was the most important independent prognostic indicator in relation to survival (p = 0.0273), with a relative risk of death of 2,4399 [95% confidence interval = 1.1051 ; 5.3871] associated with the highest microvessel counts. Moreover, the only clinicopathological variable that demonstrated prognostic value in a Cox multiple regression survival analysis was histological type (p = 0.05). In addition, we did not observe any statistical association between intratumoral microvessel density (IMD), clinicopathological variables and p53 protein expression. Key words: p53 protein - Angiogenesis - Morphometry - Prognosis - Nasopharyngeal carcinom

Rights of pasture: A strategy to conservare the extensive capríne breeds

Se plantea la utilización de los derechos de pastoreo como una estrategia de conservación de parques naturales, de la biodiversidad, así como de las economías y poblaciones asociadas. La creación de un "mercado de derechos" y la posterior asignación en base a los "derechos históricos" transforma a los ganaderos en gestores del medio ambiente, a la vez que posibilita la conservación de las razas autóctonas caprinas en peligro de extinción.It is proposed the use of the Rights of pasture like a strategy to conservate natural parks, biodiversity, as soon as connected economies and populations. The creation of a “Rights market” and the subsequent allotment on a basis of the “historical rights” transformes the cattles in environmental managers, while makes posible to conservate native carprine breds in extiction danger

At the Cutting Edge Ghrelin and reproduction: a novel signal linking energy status and fertility?

Abstract Ghrelin was originally identified in 1999 as the endogenous ligand of the growth hormone (GH) secretagogue receptor (GHS-R). Since then, an ever growing number of publications have reported the potential involvement of this molecule in the regulation of a large array of endocrine and non-endocrine functions, including the control of GH secretion and several other neuroendocrine axes as well as food intake and energy balance. On the basis of its proposed role as indicator of energy insufficiency and the proven reproductive effects of other regulators of energy homeostasis and growth (such as the adipocyte-derived hormone leptin), it is tempting to hypothesize that ghrelin might play a role in the control of reproductive function and fertility. Indeed, although evidences in this area are still fragmentary, we review herein data from different research groups, which have recently substantiated the reproductive facets of this newly identified hormone. Thus, expression of ghrelin has been demonstrated in human and rodent placenta, and ghrelin has been reported to inhibit early embryo development. In addition, ghrelin was shown to suppress luteinizing hormone (LH) secretion in vivo, and to decrease LH responsiveness to LH-releasing hormone (LHRH) in vitro. Moreover, ghrelin was able to inhibit stimulated testicular testosterone secretion, whereas androgens have been proven independent modulators of circulating ghrelin levels. In this context, our group has recently provided extensive evidence for the expression of ghrelin and its putative receptor, the type 1a GHS-R, in rat and human gonads. Testicular expression of ghrelin was highly selective for mature Leydig cells and under the hormonal control of pituitary LH, while in the ovary, expression of ghrelin was demonstrated in steroidogenically active luteal cells and interstitial hilus cells. Likewise, expression of GHS-R type 1a was demonstrated in Sertoli and Leydig cells of the testis and follicular, luteal and interstitial hilus cells in the ovary. In summary, the data so far available indicate that ghrelin may operate at different levels of the reproductive system, including the testis and the ovary, which are potential targets for systemic ghrelin actions. In addition, ghrelin is produced locally within the human and rodent gonads, where the presence of both components (ligand and receptor) of ghrelin signaling system is highly suggestive of a conserved regulatory role for this newly discovered molecule in the regulation of mammalian gonadal function. Overall, it is proposed that ghrelin may cooperate with other regulatory signals, such as leptin, in the integrated control of energy balance and reproduction