4,203 research outputs found
Category Theory and Model-Driven Engineering: From Formal Semantics to Design Patterns and Beyond
There is a hidden intrigue in the title. CT is one of the most abstract
mathematical disciplines, sometimes nicknamed "abstract nonsense". MDE is a
recent trend in software development, industrially supported by standards,
tools, and the status of a new "silver bullet". Surprisingly, categorical
patterns turn out to be directly applicable to mathematical modeling of
structures appearing in everyday MDE practice. Model merging, transformation,
synchronization, and other important model management scenarios can be seen as
executions of categorical specifications.
Moreover, the paper aims to elucidate a claim that relationships between CT
and MDE are more complex and richer than is normally assumed for "applied
mathematics". CT provides a toolbox of design patterns and structural
principles of real practical value for MDE. We will present examples of how an
elementary categorical arrangement of a model management scenario reveals
deficiencies in the architecture of modern tools automating the scenario.Comment: In Proceedings ACCAT 2012, arXiv:1208.430
Reproductive Management of Dairy Cows with Particular Reference to Organic Systems
Reproductive efficiency is a major factor affecting production and economic efficiency indairy herds. In seasonally calving herds the requirement of good reproductive performance is of greater importance than in other production systems in order to maximally exploit the use of grazed grass in the diet of the cow. Reproductive
performance of lactating dairy cows worldwide has declined over the past 30 years in association with selection for milk yield. There is increasing and consistent evidence to
suggest that at least some part of the decline in cow reproductive performance is related to underlying changes in reproductive physiology caused by high milk production and or negative energy balance (NEB) in early lactation. Organic systems of milk production demand high tight seasonal calving patterns, maximal production from grazed grass, low involuntary culling rates and the continuous genetic improvement of the herd for commercially important traits. Organic milk production systems should also allow for replacement rates of 25% - 30% to ensure a young herd age structure and low somatic cell counts (SCC). The objective of this paper is to review the role of management factors in herd reproductive performance with particular reference to organic herds
Performance and carcass traits of progeny of Limousin sires differing in genetic merit
peer-reviewedGenetic indices for growth and carcass classification are published for beef sires used in Ireland for artificial insemination (AI). The objective of this study was to compare growth and carcass traits of progeny of Limousin sires of low and high genetic index for growth. A total of 70 progeny (42 males and 28 females) out of predominantly Holstein-Friesian cows by 7 AI Limousin sires were reared together to slaughter. The 7 sires were classified as low (n=3) or high (n=4) index based on their published genetic index for growth. The male progeny were reared entire and all animals were slaughtered at about 20 months of age. Carcasses were classified for conformation and fatness, and a rib joint (ribs 6 to 10) was separated into fat, muscle and bone. Growth rate did not differ significantly between the index groups but tended to be higher for the high index progeny. This higher growth rate, combined with a significantly higher kill out proportion, resulted in carcass weight andcarcass weight per day of age being significantly higher for the high index progeny. Carcass conformation and fat class were not affected by genetic index, nor was the composition of the rib joint. Compared with males, females had a significantly lower growth rate and kill out proportion and, consequently, had a significantly lower carcass weight. The proportions of fat and bone in the rib joint were significantly higher, and the proportion of muscle was significantly lower for females than for males. It is concluded that carcass weight reflected sire group genetic index for growth but feed intake, carcass classification and rib joint composition were not affected
Targeting Assistance to the Poor and Food Insecure: A Review of the Literature
Targeting involves the identification and selection of certain groups or households or even individuals, and the distribution of benefits (or costs) to them. Targeting is required because governments face resource constraints, and because households have different needs: some are poorer and more food insecure than others. In general, the managerial costs of targeting increase with its narrowness or intended accuracy, and these costs may exceed the savings achieved by targeting. The benefits of targeting arise precisely because it reduces the size of the target population, and the cost of narrower targeting includes the unintentional exclusion of some of the target population. The literature highlights several factors common to successful public works programs, such as the need for flexibility in design and the need to pay attention to the local cultural, geographic, and economic environment in which the projects are to be implemented.food security, food policy, Food Security and Poverty, Downloads June 2008-July 2009: 21, Q18,
Understanding Linkages among Food Availability, Access, Consumption, and Nutrition in Africa: Empirical Findings and Issues from the Literature
This paper starts with the unsurprising observations that (1) having enough food available at national and local levels is necessary but not sufficient for ensuring that households have adequate access to food; (2) having adequate household access to food is necessary but not sufficient for ensuring that all household members consume an adequate diet; and (3) consuming an adequate diet is necessary but not sufficient for maintaining a healthy nutritional status. Recognizing that the links from food availability to access to consumption to nutritional status are not automatic, the challenge for policy makers and analysts concerned with achieving food and nutrition security is to understand how these variables are linked to one another, how closely they are related in various contexts, and what the important intervening variables are which affect the linkages among these variables. Unfortunately, however, our ability to understand the nature and extent of the relationships among these variables in detail has been hampered by a lack of information as well as by concerns over the appropriateness of the analytical approaches and indicators that have been used in empirical studies of these issues.food security, food policy, Food Security and Poverty, Downloads July 2008-July 2009: 14, Q18,
Following Likud’s victory in Israel, Benjamin Netanyahu faces a challenge to secure a stable coalition
Israel held legislative elections on 17 March, with the result producing a victory for incumbent Prime Minister Benjamin Netanyahu’s Likud party. Abraham Diskin writes on the coalition formation process which will follow the elections. He notes that the most likely outcome is for Netanyahu to attempt to form a coalition of the right which includes the new centrist party Kulanu
Studies relating to Polyunsaturated Fatty Acid (PUFA) Supplementation and Fertility in Cattle
End of project reportReproductive inefficiency has a significant impact on the economic performance of both dairy and beef herds, particularly in seasonal calving systems. Nutrition plays a fundamental role in reproduction. Furthermore, there is emerging evidence that supplemental dietary polyunsaturated fatty acids (PUFA) may increase cow fertility independent of their role as energy substrates. A number of studies have reported enhanced reproductive performance in dairy cows following dietary supplementation with sources of n-3 PUFA. However the possible mechanisms involved have not been identified and there is some inconsistency in the published literature on this topic. The objective of the research reported was to conduct a holistic examination of the effects of dietary long-chain n-3 PUFA supplementation on metabolic and reproductive responses in cattle. Such information is essential for the appropriate formulation of diets to enhance cow reproductive performance and in particular embryo survival
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