Microlensing By a Prolate All-Macho Halo

It is widely believed that dark matter halos are flattened, that is closer to oblate than prolate. The evidence cited is based largely on observations of galaxies which do not look anything like our own and on numerical simulations which use ad hoc initial conditions. Given what we believe to be a ``reasonable doubt'' concerning the shape of dark Galactic halo we calculate the optical depth and event rate for microlensing of stars in the LMC assuming a wide range of models that include both prolate and oblate halos. We find, in agreement with previous analysis, that the optical depth for a spherical (E0) halo and for an oblate (E6) halo are roughly the same, essentially because two competing effects cancel approximately. However the optical depth for an E6 prolate halo is reduced by ~35%. This means that an all-Macho prolate halo with reasonable parameters for the Galaxy is consistent with the published microlensing event rate.Comment: 7 pages (24K), LaTeX; 2 Postscript figure

Conservation Value and Permeability of Neotropical Oil Palm Landscapes for Orchid Bees

The proliferation of oil palm plantations has led to dramatic changes in tropical landscapes across the globe. However, relatively little is known about the effects of oil palm expansion on biodiversity, especially in key ecosystem-service providing organisms like pollinators. Rapid land use change is exacerbated by limited knowledge of the mechanisms causing biodiversity decline in the tropics, particularly those involving landscape features. We examined these mechanisms by undertaking a survey of orchid bees, a well-known group of Neotropical pollinators, across forest and oil palm plantations in Costa Rica. We used chemical baits to survey the community in four regions: continuous forest sites, oil palm sites immediately adjacent to forest, oil palm sites 2km from forest, and oil palm sites greater than 5km from forest. We found that although orchid bees are present in all environments, orchid bee communities diverged across the gradient, and community richness, abundance, and similarity to forest declined as distance from forest increased. In addition, mean phylogenetic distance of the orchid bee community declined and was more clustered in oil palm. Community traits also differed with individuals in oil palm having shorter average tongue length and larger average geographic range size than those in the forest. Our results indicate two key features about Neotropical landscapes that contain oil palm: 1) oil palm is selectively permeable to orchid bees and 2) orchid bee communities in oil palm have distinct phylogenetic and trait structure compared to communities in forest. These results suggest that conservation and management efforts in oil palm-cultivating regions should focus on landscape features.This work was supported by a Hosteling International-Austin Travel Fellowship (http://www.hiusa.org/austin) and a grant from the Graduate Program in Ecology, Evolution and Behavior at the University of Texas (http://www.biosci.utexas.edu/graduate/ee​b/default.aspx) to GL. GL was supported by a US National Science Foundation Graduate Research Fellowship. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Integrative BiologyEmail: [email protected]

Shadowland

https://digitalcommons.library.umaine.edu/mmb-vp/1358/thumbnail.jp

Class, colour consciousness and the search for identity : blacks at the Kimberley diamond diggings, 1867-1893

Bibliography: pages 168-176.The discovery of diamonds in the Kimberley area was to have far reaching consequences, not only for the region but the entire sub-continent. In addition to the hundreds of individual diggers, mainly white, who converged on this arid corner of southern Africa, there appeared also, in a remarkably short time, a complete infrastructure of urban facilities to serve their needs. Perhaps the most unique component of the otherwise colonial population was the massive influx of migrant Africans in response to the insatiable labour demands of the diamond mines. We examine the interplay of racial attitudes and conflicts and the ambiguous position of the black elites in the diverse groups of 'colonial' or 'civilised' Africans, 'Cape Coloureds', Muslims and Indians who came to Kimberley to seek their fortune. It is our contention that it was this ambiguity which was to provide a spur to black political activity. We closely consult contemporary accounts, official documentation and local newspapers, all of which faithfully record the ebb and flow of the state of racial relations. Never a typical microcosm of colonial urban society because of the extraneous factor of economic competition for limited employment and resources, social relationships in Kimberley gradually changed until the essential confrontation was not between colonials and the rest, but rather more specifically between blacks and whites. While the early history of Kimberley was marked by the virulent racism of white· diggers resisting black competition, the ensuing years were to witness a more tranquil period of racial co-existence. This tranquillity proved to be only the calm before the storm. We show how a series of crises strained relations between blacks and whites to breaking point. The failed rebellion by indigenous blacks, the smallpox epidemic during which the Muslim community incurred the wrath of white public opinion by failing to adopt western preventative measures, a revolt - the Black Flag Revolt- by militant white diggers and the effects of the new recruitment policies of the mining companies in the 1880s, which opened jobs to cheap black workers, all resulted in an increasing polarisation of race relations in Kimberley. We argue that where before official documents and newspapers had shown a class discrimination directed against migrant African labourers, this changed over time to become a negative portrayal of blacks in general. The effect of the emergence of this negative stereotype was to separate whites and blacks in many facets of life in the mining centre

A Study of Parental Attitudes Regarding Secondary Boarding Schools of the Mid-America Union of Seventh-day Adventists

Problem. One of the challenging problems of SDA education in North America is the possible trend of declining enrollment of boarding academies, which have been the mainstay of the SDA secondary school system. It was the purpose of this study to determine if a relationship existed between the declining enrollment and parental attitudes concerning the boarding academies. Method. A five-page Likert-type scale survey was used to gather information from randomly selected parents of high-school-age students in the Mid-America Union. Seven sub-hypotheses were used to test the major hypothesis which stated there would be a significant relationship between declining boarding school enrollment and parental attitudes toward the boarding school. The seven sub-hypotheses chosen covered areas of specific attitudes: financial costs, church attendance, socio-economic levels, length of church membership, dormitory concept, and the school\u27s fulfillment ofits mission. A chi-square analysis was run on the 210 surveys, applying .10 as the level for significance. Results and Conclusions. There was a significant relationship between the decline of enrollment of the boarding schools and the attitudes of parents. There was asignificant difference between parents who did not send their young people to SDA schools and parents who did send them in the areas of: quality of academics, cost of attendance, parental church attendance and length of membership, work program, faculty dedication, witnessing training, and the dormitory concept. There was no significant difference found between the two groups in the areas of: socio-economic levels, effectiveness of teachers, and parental perception of school\u27s uniqueness concerning teaching Christian beliefs and values. The study revealed that the cost of the boarding school and the dormitory situation were two negative variables that may have contributed to non-attendance. Recommendations were made in the areas of: (1) the promotion of Christian education, (2) academic achievement, (3) the cost of boarding school attendance, and (4) the dormitory situation

River Flood Modelling with Mike 11: Case of Nzoia River (Budalangi) in Kenya

This paper presents a one-dimensional unsteady flow hydraulic model used for the simulation of flow in rivers: the MIKE 11 model from the Danish Hydraulic Institute (DHI). The approach used for this model leads to unsteady flow simulations along river channel reach. The study case applied to the model is the lower Nzoia River, about 25 km in length. The study’s focus was the development of a MIKE 11 river model based on surveyed river cross-section data. The flooding problem in the lower Nzoia (Budalangi floodplains) in Kenya has been perennial each time causing a reversal of gains on economic and social development. The main objective of this study is to implement a one dimensional hydrodynamic model for the lower part of Nzoia river using the MIKE 11 modelling software. This was done with an aim of investigating the nature of the 2008 Budalangi floods. Two scenarios were considered, namely; reference case (intact dyke) and the breached dyke case. Longitudinal river stretch profiles were produced for the two cases and it was conclusive that the 2008 flooding was mainly necessitated by dyke breach. Further, the optimal computational spatial step (?x) and time step (?t) for the model were found to be 500m and 1 minute respectively. For this condition no instability of the model simulation was observed. Key words: Nzoia River, MIKE 11 hydrodynamic model, Budalangi, floodplains, river hydraulics, unsteady flo

Entropy measures as geometrical tools in the study of cosmology

Classical chaos is often characterized as exponential divergence of nearby trajectories. In many interesting cases these trajectories can be identified with geodesic curves. We define here the entropy by $S = \ln \chi (x)$ with $\chi(x)$ being the distance between two nearby geodesics. We derive an equation for the entropy which by transformation to a Ricatti-type equation becomes similar to the Jacobi equation. We further show that the geodesic equation for a null geodesic in a double warped space time leads to the same entropy equation. By applying a Robertson-Walker metric for a flat three-dimensional Euclidian space expanding as a function of time, we again reach the entropy equation stressing the connection between the chosen entropy measure and time. We finally turn to the Raychaudhuri equation for expansion, which also is a Ricatti equation similar to the transformed entropy equation. Those Ricatti-type equations have solutions of the same form as the Jacobi equation. The Raychaudhuri equation can be transformed to a harmonic oscillator equation, and it has been shown that the geodesic deviation equation of Jacobi is essentially equivalent to that of a harmonic oscillator. The Raychaudhuri equations are strong geometrical tools in the study of General Relativity and Cosmology. We suggest a refined entropy measure applicable in Cosmology and defined by the average deviation of the geodesics in a congruence.Comment: Final Versio

Daphnia Halloween genes that encode cytochrome P450s mediating the synthesis of the arthropod molting hormone: Evolutionary implications

<p>Abstract</p> <p>Background</p> <p>In crustaceans and insects, development and reproduction are controlled by the steroid hormone, 20-hydroxyecdysone (20E). Like other steroids, 20E, is synthesized from cholesterol through reactions involving cytochrome P450s (CYPs). In insects, the CYP enzymes mediating 20E biosynthesis have been identified, but evidence of their probable presence in crustaceans is indirect, relying solely on the ability of crustaceans to synthesize 20E.</p> <p>Results</p> <p>To investigate the presence of these genes in crustaceans, the genome of <it>Daphnia pulex </it>was examined for orthologs of these genes, the Halloween genes, encoding those biosynthetic CYP enzymes. Single homologs of <it>spook-CYP307A1</it>, <it>phantom-CYP306A1</it>, <it>disembodied-CYP302A1</it>, <it>shadow-CYP315A1 </it>and <it>shade-CYP314A1 </it>were identified in the <it>Daphnia </it>data base. Phylogenetic analysis indicates an orthologous relationship between the insect and <it>Daphnia </it>genes. Conserved intron/exon structures and microsynteny further support the conclusion that these steroidogenic CYPs have been conserved in insects and crustaceans through some 400 million years of evolution.</p> <p>Conclusion</p> <p>Although these arthropod steroidogenic CYPs are related to steroidogenic CYPs in <it>Caenorhabditis elegans </it>and vertebrates, the data suggest that the arthropod steroidogenic CYPs became functionally specialized in a common ancestor of arthropods and are unique to these animals.</p

Behavioral discrimination between monogyne and polygyne red fire ants (Hymenoptera: Formicidae) in their native range

Nestmate recognition among social insects is presumed to restrict non-nestmates from exploiting nest resources. Here, we developed aggression bioassays to assess the discrimination behaviors of both polygynous and monogynous forms of the red fire ant, Solenopsis invicta Buren, during symmetrical interactions in neutral arenas. Workers from polygyne colonies exhibited risk avoidance behaviors; that is, defensive postures or the avoidance of direct contact during interactions. Workers from monogyne colonies always exhibited aggressive behaviors in the form of physical or chemical attacks. In interactions between both, monogyne workers usually started the aggression by surrounding and biting the polygyne ants. Polygyne S. invicta workers also distinguished nestmates from foreigners, but their response was not as aggressive as that of monogynes. The proposed ethogram that we constructed identified monogyne and polygyne forms of S. invicta colonies in concordance with current measures, including number of queens, and expression of the Gp-9 gene.Fil: Chirino, Monica Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Centro de Estudios e Investigación; ArgentinaFil: Gilbert, Lawrence E.. University of Texas at Austin; Estados UnidosFil: Folgarait, Patricia Julia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Centro de Estudios e Investigación; Argentin

Perceived Roles of Religious and Cultural Teachers in Implementing the Curriculum towards Achieving and Sustaining Peace in Imo State

The study investigated the perceived roles of Religious and Cultural Teachers in Implementing the Curriculum towards Achieving and Sustaining Peace in Imo State. The study was guided by two research questions and one hypothesis. Descriptive survey research design was adopted for the study. Multistage proportionate stratified random sampling techniques were used to draw a sample of 224 Christian religious teachers from population of 602 Christian religious teachers in junior and senior public secondary schools. Researchers developed two rating scales: Religious and Cultural Teachers Roles in Peace Achievement Rating Scale (RCTRPARS) and Level Religious and Cultural Teachers Discharge their Roles Towards Achieving Peace Rating Scale (LRCTDRTAPRS). The reliability of internal consistency of RCTPPARS and LRCTDRTAPRS are 0.86 and 0.82 respectively while reliability of temporal stability are 0.80 and 0.83 respectively. Mean and standard deviations were used to answer the research questions while z-test statistics was used to test the hypothesis at 0.05 significant levels. Findings showed the sixteen specific roles religious and cultural teachers are expected to play in discharging these duties, the religious and cultural teachers have significantly performed below the expected average level. Religious and cultural teachers should endeavour to be more proactive in the discharge of their duties in these areas through effective curriculum implementation so as to enhance the realization of peaceful society for all citizens