ECONOMICS OF ALTERNATIVE BEEF CATTLE GENOTYPE AND MANAGEMENT/MARKETING SYSTEMS

Livestock Production/Industries,

INTEGRATION, RISK, AND SUPPLY RESPONSE: A SIMULATION AND LINEAR PROGRAMMING ANALYSIS OF AN EAST TEXAS COW-CALF PRODUCER

Livestock Production/Industries,

A Hilbert Scheme in Computer Vision

Multiview geometry is the study of two-dimensional images of three-dimensional scenes, a foundational subject in computer vision. We determine a universal Groebner basis for the multiview ideal of n generic cameras. As the cameras move, the multiview varieties vary in a family of dimension 11n-15. This family is the distinguished component of a multigraded Hilbert scheme with a unique Borel-fixed point. We present a combinatorial study of ideals lying on that Hilbert scheme.Comment: 26 page

Effect of temperature, rainfall and planting date on aflatoxin and fumonisin contamination in commercial Bt and non-Bt corn hybrids in Arkansas

Corn (maize, Zea mays) is susceptible to contamination with aflatoxins, fumonisins and other mycotoxins, particularly in the southeastern USA. In principle, mycotoxin contamination could be reduced in commercial corn hybrids with shorter growing seasons by planting at dates which minimize plant stress during the critical kernel-filling period. To evaluate this strategy, commercial Bt and non-Bt hybrids were planted in Arkansas in mid-April and early May of 2002, 2004 and 2005. The mid-April planting date resulted in lower aflatoxin contamination in harvested corn each yr and in significantly less frequent contamination above a regulatory action level in 2005 and overall than did the early-May planting date in both Bt and non-Bt corn. The mid-April planting date resulted in significantly lower total fumonisin contamination in harvested corn and in less frequent contamination above a regulatory advisory level than the early May planting date in 2 of 3 yr and overall in both Bt and non-Bt corn. All fumonisin subtypes studied were reduced. Frequent co-occurrence of aflatoxin and fumonisin was observed. Fumonisin levels averaged lower in Bt hybrids than in non-Bt hybrids at all plantings. Reduced aflatoxin and fumonisin contamination with mid-April planting could not be explained by any measure of heat stress during the kernel-filling period.Le maïs (Zea mays) est sensible à la contamination par les aflatoxines, les fumonisines et d'autres mycotoxines, surtout dans le sud-est des États-Unis. En principe, la contamination par les mycotoxines pourrait être diminuée chez les hybrides commerciaux de maïs par des saisons de croissance plus courtes en plantant à des dates qui minimisent le stress sur les plantes au moment de la période critique du remplissage des grains. Pour évaluer cette stratégie, des hybrides commerciaux Bt et non Bt ont été semés en Arkansas de la mi-avril au début de mai 2002, 2004 et 2005. Pour toutes les années, tant pour le maïs Bt que le non Bt, le grain issu des semis de la mi-avril était moins contaminé aux aflatoxines que celui semé au début de mai. De même, la contamination supérieure aux niveaux légalement acceptés a été moindre en 2005 et dans l'ensemble pour les semis de la mi-avril. Avec les semis de la mi-avril, il y avait significativement moins de contamination par les fumonisines dans le grain récolté et moins de contamination supérieure aux niveaux légalement acceptés qu'avec les semis du début de mai pour deux des trois années et dans l'ensemble, tant pour le maïs Bt que celui non Bt. La quantité de tous les sous-types de fumonisines étudiés a été diminuée. La présence simultanée d'aflatoxines et de fumonisines a fréquemment été observée. Pour tous les semis, les quantités de fumonisines des hybrides Bt ont été inférieures en moyenne à celles des hybrides non Bt. Les moindres contaminations par les aflatoxines et les fumonisines avec les semis de la mi-avril n'ont pu être expliquées par aucune des mesures du stress causé par la chaleur lors de la période du remplissage des grains

Community safety in an age of austerity: an urban regime analysis of Cardiff 1999-2015

The political and economic context following the election of the Coalition Government in 2010 has had a significant impact upon community safety work in England and Wales. More specifically, the governmental austerity agenda - the term given to policies aimed at reducing sovereign debt through reductions in public expenditure - and the introduction of locally elected Police and Crime Commissioners present a number of challenges for community safety and the local coordination of multi-agency partnership practices around crime and disorder. In addition, the currently dominant discourses and policies of localism and a decentralisation of power have placed greater emphasis on the role of locally situated actors in having to choose how to respond to the external political and economic constraints placed upon them. Borrowing and adapting concepts from regime theory, this research employs a single-embedded case study of community safety in Cardiff to examine how the Cardiff policy ‘regime’ has sought to respond to the current economic and political climate. Building upon the analytical framework offered by regime theory, and utilising a combination of ethnographic observations, interviews and documentary analysis of policy texts over the last two decades, this thesis explores the changes to the governing arrangements in Cardiff, from a well resourced multi-agency community safety team, to the dispersal of responsibility for community safety under the guise of integration and reducing complexity. Demonstrating the opportunities presented by localism the research finds evidence of an attempt to form a governing regime around a ‘transformative’ strategic agenda orientated around ideas of social justice and civic inclusion. However, illustrating the constraints on this freedom afforded to local governing actors, the realisation of this strategic agenda has been compromised by changes to the governing arrangements in Cardiff that have resulted in a degradation of governing capacity for community safety and the hollowing out of community safety expertise in the city. Accordingly, the research finds evidence of a disparity between the transformative rhetoric of the shared strategic agenda, and the fragmented and divergent operational practices of community safety. This use of regime theory makes an original contribution to the nascent conceptual and empirical debate about the contested and uncertain future of community safety in an age of austerity. It highlights the need for further locally situated case studies that can disambiguate the political agency available to local policy actors and the external political and economic constrains placed upon them

Observation and contagion effects in cooperation: An experimental investigation

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.We experimentally disentangle two potential sources for endogenous social interactions effects. By comparing groups where the aggregate behavior is publicly observable with those where it is not we can measure the size of any endogenous observation effect. By comparing connected with disconnected groups we can measure the size of any endogenous contagion effect. Results are provided for both a coordination game and social dilemma. We find strong evidence of an endogenous observation effect in the coordination game but not social dilemma. We find no evidence of an endogenous contagion effect in either game. While our results point towards a conformity effect we argue that information on group behavior primarily acts as a coordinating device which may be reflected in changes in beliefs

Rock mechanical properties of immature, organic-rich source rocks and their relationships to rock composition and lithofacies

Mechanical properties of layered rocks are critical in ensuring wellbore integrity and predicting natural fracture occurrence for successful reservoir development, particularly in unconventional reservoirs for which fractures provide the main pathway for hydrocarbon flow. We examine rock mechanical properties of exceptionally organic-rich, immature source rocks from Jordan, and understand their relationships with rock mineral composition and lithofacies variations. Four depositional microfacies were identified: organic-rich mudstone, organic-rich wackestone, silica-rich packstone and fine-grained organic-rich wackestone. The four types exhibit various mineralogical compositions, dominated by carbonates, biogenic quartz and apatite. Leeb hardness ranges between 288 and 654, with the highest average values occurring in silica-rich packstone and organic-rich mudstone. The highest uniaxial compressive strength (derived from the intrinsic specific energy measured using an Epslog Wombat scratch device), and compressional- and shear-wave velocities were measured in organic-rich mudstones (140 MPa, 3368 m s−1 and 1702 m s−1, respectively). Porosity shows higher average values in organic-rich wackestones and fine-grained organic-rich wackestones (33–35%). Silica-rich packstone and organic-rich mudstone have brittle properties, while organic-rich wackestone and fine-grained organic-rich wackestone are ductile. High silica contents are correlated positively with brittleness. A strong hardness–brittleness correlation suggests that Leeb hardness is a useful proxy for brittleness. Our study allows a better understanding of the relationships between lithofacies, organic content and rock mechanical properties, with implications for fracking design to well completion and hydrocarbon production. Further work involving systematic sampling and a more rigorous study is still required to better understand the spatial distribution of target lithologies and their mechanical properties

Cement nanotubes: on chemical gardens and cement

© 2016 Springer Science+Business Media New York“Do cement nanotubes exist?” is a question that has recently been asked. The answer is yes, they do exist. The evidence is in the literature, in tens of papers showing in detail chemical garden-type tubes in cement from the nanoscale upwards that were published in the 1970s and 1980s. Here, we present a nano-review of the literature

Phylogenetics of Trachylina (Cnidaria: Hydrozoa) with new insights on the evolution of some problematical taxa

Some of the most interesting and enigmatic cnidarians are classified within the hydrozoan subclass Trachylina. Despite being relatively depauperate in species richness, the clade contains four taxa typically accorded ordinal status: Actinulida, Limnomedusae, Narcomedusae and Trachymedusae. We bring molecular data (mitochondrial 16S and nuclear small and large subunit ribosomal genes) to bear on the question of phylogenetic relationships within Trachylina. Surprisingly, we find that a diminutive polyp form, Microhydrula limopsicola (classified within Limnomedusae) is actually a previously unknown life stage of a species of Stauromedusae. Our data confirm that the interstitial form Halammohydra sp. (Actinulida) is derived from holopelagic direct developing ancestors, likely within the trachymedusan family Rhopalonematidae. Trachymedusae is shown to be diphyletic, suggesting that the polyp stage has been lost independently at least two times within trachyline evolution. Narcomedusae is supported as a monophyletic group likely also arising from trachymedusan ancestors. Finally, some data, albeit limited, suggest that some trachyline species names refer to cryptic species that have yet to be sorted taxonomicall