586 research outputs found
A study of patchiness in mid-season dairy pastures : consequences and control : a thesis presented in partial fulfilment of the requirements for the degree of Master of Applied Science at Massey University
There is interest among some dairy farmers in increasing herbage intake of cows during spring by increasing pasture cover but without compromising pasture quality into the summer. "Late control" is a grazing management strategy developed in Massey University that meets those requirements (Matthews et al., 1996). In addition, it has been demonstrated in previous trials that Late control increases pasture production in the summer-autumn period by increasing ryegrass tillering vigour. Late control requires a period of lax grazing during spring to allow some reproductive growth development on ryegrass pastures, which is then controlled by hard grazing in late spring before anthesis. However, patchiness may develop in Late control during the lax grazing period when the herbage allowance is high. The objectives for the present experiment were to compare the pasture characteristics under Late control and conventional "Early control" spring management strategies in December-January, with particular reference to the consequences of vegetation heterogeneity to pasture production and utilisation over this period, and to discuss the implications to spring grazing management. The experiment involved detailed studies on three paddocks chosen from each of two farmlets of 22 paddocks used for a system trial comparing Early and Late control spring management on herds of 120 cows. Herbage mass distributions were estimated by taking 200 capacitance meter readings at random on each paddock. Relationships between herbage mass and utilisation and accumulation were estimated by using two 30 m permanent transects in each paddock. To determine botanical composition and tiller population variability within a sward, five tall patches and five short patches were sampled in each paddock. Paddocks in Late control before the control phase in December had more herbage mass than paddocks in Early control (3600 vs. 5000 kg DM/ha), but the variability of herbage mass was similar (1000 vs. 1000, standard deviation in kg DM/ha). The skewness of the herbage mass distribution was positive but greater in Early control than in Late control (0.57 vs. 0.32). Botanical composition was similar between treatments and within paddocks. Pasture morphology showed tiller size-density compensation in both treatments. Pasture characteristics in late control were not an impediment for efficient pasture removal in late control and more herbage was harvested than in Early control (1900 vs. 1000 kg DM/ha), although herbage allowance was greater in Early control. Short patches in both treatments were defoliated in less proportion than tall patches, but in Late control the proportion of short patches was less than in Early control. Therefore, low herbage mass and greater proportion of short patches in Early control had a negative effect on total herbage utilisation. Harvesting efficiency was controlled on Late control paddocks to avoid limitations to herbage intake, and the skewness of the distribution of herbage mass after grazing increased compared to Early control, as well as the proportion of tall poorly utilised patches. Topping of pastures after grazing was effective in removing poorly utilised material and in decreasing patchiness in January. In January, Late control paddocks had more herbage mass, but less patchiness than Early control paddocks (6300 vs. 4700 kg DM/ha). Sward characteristics were affected by treatment, and in general Late control increased ryegrass content and its leafiness during January compared to Early control. In January, herbage utilisation was greater in Late control than in Early control (3000 vs. 1700 kg DM/ha). It was concluded that because Late control had greater responses in tall patches, the objective should be to modify management to a longer rotation length before controlling reproductive growth in late spring, to allow a greater proportion of the sward to achieve high herbage mass. The combination of grazing and topping of pastures gave high herbage intakes and effective pasture control. More pasture was produced in Late control than in Early control and the rotation length can also be increased during the summer in Late control, which may benefit further ryegrass tillering
El Cid, un personaje transfronterizo
RESUMEN: En trabajos anteriores habíamos definido al Cid Campeador como un “habitante de frontera”, expresión que pretendía resaltar el carácter aventurero y arriesgado de Rodrigo Díaz, tanto en su actuación política como, sobre todo, militar. Del repaso de su vida, ciertamente, se saca la impresión de haber sido vivida constantemente al límite. Pues bien, sin perder de vista esta valoración de anteriores trabajos, ofrecemos en este artículo una nueva perspectiva de análisis para mejor entender el paso del Cid por la historia; por su historia concreta y limitada, y por los siglos en que su imagen se ha prolongado al amparo de la leyenda y del mito. Y acometemos este análisis utilizando una nueva palabra clave para definir a este personaje como un sujeto transfronterizo; es decir, como un individuo que sabe desenvolverse con soltura, incluso con fortuna, en etapas históricas, ambientes culturales, legalidades y formas de presencia radicalmente diferentes.ABSTRACT: In previous works, we have defined el Cid Campeador as an “inhabitant of the frontiers” of Christendom, a turn-of-phrase intended to highlight the adventurous and daring character of Rodrigo Díaz in his political life and, above all, in his military engagements. A review of his past certainly leaves a lasting impression that he lived his life to the hilt. Without losing touch with this viewpoint expressed in previous works, a new analytical perspective is advanced in this article to gain a deeper understanding of el Cid’s passage through history; through his own specific, time-bound history, and through those centuries in which his name lived on, taking refuge in both legend and myth. We begin this analysis referring to a new keyword that defines el Cid as a historical figure who crossed frontiers; in other words, as an individual who was able to conduct himself with almost fortuitous ease, in the face of radically different historical periods, cultural realms, codes of law, and demeanours.</p
La sombra del Cid y de otros mitos medievales en el pensamiento franquista
El pensamiento franquista, huérfano de argumentos para legitimar y enraizar la figura del caudillo Francisco Franco en la historia de España, busca su fuente nutricia, entre otros referentes ideales, en algunas leyendas y mitos de ascendencia medieval hispana: el de la Reconquista y Cruzada, o lucha sin cuartel contra el infiel musulmán; el de Fernán González, presunto símbolo de la defensa de la unidad de Castilla y, por extensión, de toda España; o el del Cid, ilusorio arquetipo del defensor de la patria, legendario vasallo siempre fiel y leal a su rey y a su reino, utópico cancerbero de la moralidad pública y garante imaginario de la continuidad en el ejercicio del poder.Francoist thought, bereft of arguments to legitimize and embed the figure of the Caudillo Francisco Franco in the history of Spain, sought its inspirational sources, among other ideal references, in various legends and myths of Spanish medieval stock: the Reconquista and the Crusades, or the allout war against the Muslim infidel; that of Fernán González, supposedly the symbolic defender of Castilian unity and, by extension, of the rest of Spain; or that of El Cid, illusory archetype of the defender of the Fatherland, legendary vassal of constant faith and loyalty to his king and to his kingdom, utopian guardian of public morality, and imaginary guarantor of continuity in the exercise of power.peerReviewe
Castilla, 1065: un reino prematuro
Por inercia, los historiadores hispanos sitúan la elevación
del condado de Castilla a la categoría de reino en los años 1035
o inmediatamente siguientes. El dato, sin embargo, puede ponerse
bajo sospecha si repasamos detenidamente la realidad sociopolítica
del momento en el conjunto del reino de León. En este trabajo, a modo
de aproximación y sugerencia, defendemos el retraso del momento
hasta la fecha de toma de posesión del reino castellano –indudablemente
ya reconocido como tal– por parte de Sancho II en 1065, aunque
su consolidación no se hará efectiva sino unas décadas más tarde.From habit, Spanish historians consider the elevation
of Castile from an earldom to a kingdom by 1035 or the immediate
following years. This fact can be questioned following a deep analysis
of the sociopolitical reality of that time throughout the kingdom
of Leon. In this study it will be defended, as an approximation and
a suggestion, a retardation of this event till the moment in which
Sancho II took over the Castilian kingdom –at that moment un -
doubtedly acknowledged as a kingdom– which occurred in 1065,
although the consolidation of the kingdom will not be effective till
some decades later
Ultrasound-Assisted Extraction, Followed by Gas Chromatography–Mass Spectrometry for the Simultaneous Quantification of Ethinyl Estradiol and Drospirenone in Contraceptive Formulations
[EN]Contraceptive tablets typically contain a combination of two synthetic versions of an estrogen and a progestogen, which work together to inhibit the ovulation process. An accurate and precise quantification of these components is essential for contraceptive producers. In this study, we have developed the first gas chromatography–mass spectrometry (GC–MS) method for the simultaneous quantification of 17α-ethinyl estradiol (EE) and drospirenone (DP) in contraceptive formulations. Under the final working conditions, analytes were extracted from the solid by ultrasound-assisted extraction (15 min) in methanol. The resulting suspension was diluted in ethyl acetate, subjected to centrifugation and, finally, the supernatant was directly injected into the GC–MS system. No derivatization reagents were utilized. To correct for instrumental variations, calibration was performed using the internal standard method, with cholesterol as the internal standard. A good linearity was achieved throughout the calibration range for both EE (3–12 µg mL−1) and DP (300–1200 µg mL−1), with R2 values exceeding 0.99. Trueness, assessed in terms of percentages of recovery, was also found to be satisfactory for both analytes, with recovery rates of 106 ± 8% for EE and 93 ± 9% for DP. Furthermore, intra-day and inter-day precision studies yielded relative standard deviation values below 6% for both analytes. In terms of sensitivity, the instrumental limits of detection were 0.25 µg mL−1 for EE and 6.6 µg mL−1 for DP, and the instrumental limits of quantification 0.82 µg mL−1 for EE and 22 µg mL−1 for DP. The method was successfully applied to the analysis of contraceptive tablets from three different pharmaceutical companies. No differences were observed between the measured and the declared amount of active principle per tablet, demonstrating the applicability of the procedure. In addition, a stability study conducted on both the standards and sample extracts demonstrated that they can be stored at room temperature for a minimum period of seven days.Junta de Castilla y Leó
Los documentales científicos como instrumentos de educación para la sostenibilidad
El objeto de este trabajo se centra en analizar el papel que están jugando y pueden llegar a jugar los documentales científicos que se difunden ampliamente a través de la TV, venta en quioscos, etc., en la formación de una ciudadanía consciente de los problemas a los que se enfrenta hoy la humanidad y preparada para participar en la adopción de las medidas necesarias
El estudio de la energía en la educación tecnológica: una ocasión privilegiada para analizar la situación del mundo
El propósito de este trabajo es mostrar cómo el estudio de la energía constituye una ocasión privilegiada para abordar la situación del mundo y contribuir a una mejor comprensión de los problemas y las medidas que se pueden adoptar ante la actual situación de emergencia planetaria. Y se plantea como una contribución, desde el ámbito de la educación tecnológica, a los objetivos de la Década de la Educación para el Desarrollo Sostenible que Naciones Unidas, ante la gravedad de los problemas, promueve de 2005 a 2014
Papel de la Energía en nuestras vidas : una ocasión privilegiada para el estudio de la situación del mundo
El objetivo de este trabajo es presentar un programa de actividades centrado en el estudio de la energía como contribución a una mejor comprensión de la actual situación de emergencia planetaria, estrechamente vinculada a la obtención y uso de recursos energéticos, así como para generar actitudes y comportamientos adecuados para hacer frente a los problemas que caracterizan dicha situación. Este material didáctico ha sido utilizado en talleres dirigidos a profesores en formación inicial y permanente, así como a estudiantes de universidad y de secundaria, con resultados que quedan recogidos en los comentarios a las actividades
Mercados Informales y Control Vertical: Comercialización de Pesca Artesanal Perecible
This paper offers an in-depth case study analysis about institutional changes occurring since the late 1990s at the Chilean Austral Hake artisanal fishery. This high-value exporting fishery, specialized on selling fresh-chilled products, represents a pioneering example of self-government developments within artisanal fishermen's communities exploiting mobile marine resources in Chile. Despite entry restrictions and global catch quotas, this fishery faced a productivity crisis from the late 1980s up to the second half of the 1990s. As a response to this, fishermen initiated talks with the Government in order to introduce new management rules. After gradual evolution, today there prevails a well-developed system of de facto individual non-transferable quotas subject to a high degree of self-management by fishermen organizations. We discuss industrial organization issues which condition the exchange solutions found at this fishery. In particular, we discuss incentives derived from industrial concentration and buyer power, vertical integration and other strategies of vertical control between transacting parties at this industry; namely, between wholesale marketing brokers, exporters, processors, direct buyers of the catch and fishermen. Contractual issues of relevancy are: the use of informal markets; multi-dimensional contracting; temporal specificity due to product perishability; the use of different instruments for vertical control; and the influence of increasing degrees of industrial concentration as we advance through the wholesale commercialization channel, moving closer to the retailing stages at final export markets.Producción y comercialización de Alimentos; Cadenas de producción; Control y Coordinación Vertical; Pesca Artesanal en Chile; Merluza Austral.
- …