6 resultados para Chiloscyllium punctatum, Crescita, Sacco vitellino, Sviluppo embrionale, Illuminamento, Acquario

em CentAUR: Central Archive University of Reading - UK


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This study investigated the potential of Dichrostachys cinerea fruits as a protein supplement in semi-arid areas of Zimbabwe. The tanniniferous fruits were treated with aqueous solutions of polyethylene glycol (PEG) or sodium hydroxide (NaOH). Both treatments increased the soluble fraction, rate of degradation and effective degradability (ED) of nitrogen (N) in sacco. The PEG effects were higher than the NaOH effects (e.g. a 25% vs. 6% increase in effective N degradabilities, respectively). Five treatments were evaluated in a N-balance trial using Matebele goats: ground, PEG- or NaOH-treated D. cinerea fruits, a commercial protein supplement (CPS) and no supplement. Animals offered ground fruits or CPS retained most N (3.7 or 4.1 g N/day, respectively), while those offered NaOH- or PEG-treated fruits retained significantly less N (2.7 or 1.0 g/day, respectively). Unsupplemented animals were in negative N balance (-2.4 g/day). PEG treatment deactivated the tannins more than the NaOH treatment. PEG treatment resulted in excessive protein degradation in the rumen leading to high urine N loss. It is concluded that the D. cinerea fruits were beneficial for goat N-nutrition and that the tannins did not require inactivation. D. cinerea fruits can, therefore, replace the expensive commercial protein supplement. It is also suggested that the collection and grinding of fruits could be used as a management tool to control bush encroachment. (C) 2004 Elsevier B.V. All rights reserved.

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As the ideal method of assessing the nutritive value of a feedstuff, namely offering it to the appropriate class of animal and recording the production response obtained, is neither practical nor cost effective a range of feed evaluation techniques have been developed. Each of these balances some degree of compromise with the practical situation against data generation. However, due to the impact of animal-feed interactions over and above that of feed composition, the target animal remains the ultimate arbitrator of nutritional value. In this review current in vitro feed evaluation techniques are examined according to the degree of animal-feed interaction. Chemical analysis provides absolute values and therefore differs from the majority of in vitro methods that simply rank feeds. However, with no host animal involvement, estimates of nutritional value are inferred by statistical association. In addition given the costs involved, the practical value of many analyses conducted should be reviewed. The in sacco technique has made a substantial contribution to both understanding rumen microbial degradative processes and the rapid evaluation of feeds, especially in developing countries. However, the numerous shortfalls of the technique, common to many in vitro methods, the desire to eliminate the use of surgically modified animals for routine feed evaluation, paralleled with improvements in in vitro techniques, will see this technique increasingly replaced. The majority of in vitro systems use substrate disappearance to assess degradation, however, this provides no information regarding the quantity of derived end-products available to the host animal. As measurement of volatile fatty acids or microbial biomass production greatly increases analytical costs, fermentation gas release, a simple and non-destructive measurement, has been used as an alternative. However, as gas release alone is of little use, gas-based systems, where both degradation and fermentation gas release are measured simultaneously, are attracting considerable interest. Alternative microbial inocula are being considered, as is the potential of using multi-enzyme systems to examine degradation dynamics. It is concluded that while chemical analysis will continue to form an indispensable part of feed evaluation, enhanced use will be made of increasingly complex in vitro systems. It is vital, however, the function and limitations of each methodology are fully understood and that the temptation to over-interpret the data is avoided so as to draw the appropriate conclusions. With careful selection and correct application in vitro systems offer powerful research tools with which to evaluate feedstuffs. (C) 2003 Elsevier B.V. All rights reserved.

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“La questione di Trieste”, ovvero la questione del confine italo-yugoslavo all’indomani della seconda guerra mondiale costituisce da lungo tempo oggetto di attenzione e di esame da parte della storiografia italiana e straniera. Con alcune importanti eccezioni, la ricostruzione complessiva di quelle vicende ha visto il più delle volte il prevalere di un approccio storico-diplomatico che ha reso difficile comprendere con chiarezza i rapporti e le interdipendenze fra contesto locale, contesto nazionale e contesto internazionale. Attraverso la lettura incrociata dell’ampia documentazione proveniente dai fondi dei National Archives Records Administration (NARA) questo studio tenta una rilettura delle varie fasi di sviluppo della questione nel periodo compreso tra il giugno del 1945 e l’ottobre del 1954 secondo una duplice prospettiva: nella prima parte si concentra sulla politica americana a Trieste, guardando nello specifico a due aspetti interni tra loro strettamente correlati, la gestione dell’ordine pubblico e la “strategia” del consenso da realizzarsi mediante il controllo dell’informazione da un lato e la promozione di una politica culturale dall’altro. Sono aspetti entrambi riconducibili al modello del direct rule, che conferiva al governo militare alleato (GMA) piena ed esclusiva autorità di governo sulla zona A della Venezia Giulia, e che ci appaiono centrali anche per cogliere l’interazione fra istituzioni e soggetti sociali. Nella seconda parte, invece, il modificarsi della fonte d’archivio indica un cambiamento di priorità nella politica estera americana relativa a Trieste: a margine dei negoziati internazionali, i documenti del fondo Clare Boothe Luce nelle carte dell’Ambasciata mostrano soprattutto come la questione di Trieste venne proiettata verso l’esterno, verso l’Italia in particolare, e sfruttata – principalmente dall’ambasciatrice – nell’ottica bipolare della guerra fredda per rinforzare il sostegno interno alla politica atlantica. Il saggio, dunque, si sviluppa lungo due linee: dentro e fuori Trieste, dentro 1945-1952, fuori 1953-1954, perché dalle fonti consultate sono queste ad emergere come aree di priorità nei due periodi. Abstract - English The “Trieste question”, or the question regarding the Italian - Yugoslav border after the Second World War, has been the object of careful examination in both Italian and foreign historiography for a long time. With a few important exceptions, the overall reconstruction of these events has been based for the most part on historic and diplomatic approaches, which have sometimes made it rather difficult to understand clearly the relationships and interdependences at play between local, national and international contexts. Through a comparative analysis of a large body of documents from the National Archives and Records Administration (NARA), College Park MD, this essay attempts a second reading of the various phases in which the question developed between June 1945 and October 1954, following a twofold perspective: the first part focuses on American policy for Trieste, specifically looking at two internal and closely linked aspects, on the one hand, the management of ‘law and order’, as well as a ‘strategy’ of consent, to be achieved through the control of all the means of information , and, on the other, the promotion of a cultural policy. Both aspects can be traced back to the ‘direct rule’ model, which gave the Allied Military Government (AMG) full and exclusive governing authority over Venezia Giulia’s Zone A. These issues are also fundamental to a better understanding of the relationships between institutions and social subjects. In the second part of the essay , the change in archival sources clearly indicates a new set of priorities in American foreign policy regarding Trieste: outside any international negotiations for the settlement of the question, the Clare Boothe Luce papers held in the Embassy’s archives, show how the Trieste question was focused on external concerns, Italy in particular, and exploited – above all by the ambassador – within the bi-polar optic of the Cold War, in order to strengthen internal support for Atlantic policies. The essay therefore follows two main lines of inquiry: within and outside Trieste, within in 1945-1952, and outside 1953-1954, since, from the archival sources used, these emerge as priority areas in the two periods.

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Global climate change and a growing population require tackling the reduction in arable land and improving biomass production and seed yield per area under varying conditions. One of these conditions is suboptimal water availability. Here, we review some of the classical approaches to dealing with plant response to drought stress and we evaluate how research on RECEPTOR-LIKE KINASES (RLKs) can contribute to improving plant performance under drought stress. RLKs are considered as key regulators of plant architecture and growth behavior, but they also function in defense and stress responses. The available literature and analyses of available transcript profiling data indeed suggest that RLKs can play an important role in optimizing plant responses to drought stress. In addition, RLK pathways are ideal targets for nontransgenic approaches, such as synthetic molecules, providing a novel strategy to manipulate their activity and supporting translational studies from model species, such as Arabidopsis thaliana, to economically useful crops.