3,170 research outputs found

    Fecundity and oviposition behaviour of the cowpea seed beetle, Callosobruchus maculatus (Fabricius)

    Get PDF
    The reproductive biology of three strains of Callosobruchus maculatus F. (Coleoptera: Bruchidae), the cowpea-seed beetle, was studied. This beetle is a serious pest of stored legume seeds in the semi-arid tropics.As females aged, energy reserves were depleted and aspects of this decline were related to the number of eggs laid in order to explain the observed daily egg laying pattern of C. macuiatus. Various factors affected the fecundity of females. The initial adult weight of females showed a strong positive relationship with the number of eggs laid. Substances, which could be extracted from cowpeas, were shown to be necessary to allow normal oviposition on an artificial substrate, glass beads. The male contribution to female fecundity was also investigated. Approximately half of the study was concerned with factors which govern a female's choice of oviposition site. The presence of a pheromone which enabled females to distribute their eggs more efficiently among cowpeas was demonstrated. This demonstration necessitated the development of a bioassay using a choice chamber which allowed beetles to choose between cowpeas marked with pheromone and control cowpeas. Using the bioassay, the solubility of the pheromone in different solvents was examined. The persistence of the pheromone over different periods of time was investigated and it was shown that the pheromone can remain active for at least thirty days.In addition to the marking pheromone, the role of physical characteristics of the oviposition substrates was also studied. The surface area and weight of such substrates were shown to affect the choice of oviposition site by females. The results obtained are discussed in the context of previous work on bruchids, particularly models of oviposition behaviour proposed by some workers.<p

    A statistical framework for testing functional categories in microarray data

    Get PDF
    Ready access to emerging databases of gene annotation and functional pathways has shifted assessments of differential expression in DNA microarray studies from single genes to groups of genes with shared biological function. This paper takes a critical look at existing methods for assessing the differential expression of a group of genes (functional category), and provides some suggestions for improved performance. We begin by presenting a general framework, in which the set of genes in a functional category is compared to the complementary set of genes on the array. The framework includes tests for overrepresentation of a category within a list of significant genes, and methods that consider continuous measures of differential expression. Existing tests are divided into two classes. Class 1 tests assume gene-specific measures of differential expression are independent, despite overwhelming evidence of positive correlation. Analytic and simulated results are presented that demonstrate Class 1 tests are strongly anti-conservative in practice. Class 2 tests account for gene correlation, typically through array permutation that by construction has proper Type I error control for the induced null. However, both Class 1 and Class 2 tests use a null hypothesis that all genes have the same degree of differential expression. We introduce a more sensible and general (Class 3) null under which the profile of differential expression is the same within the category and complement. Under this broader null, Class 2 tests are shown to be conservative. We propose standard bootstrap methods for testing against the Class 3 null and demonstrate they provide valid Type I error control and more power than array permutation in simulated datasets and real microarray experiments.Comment: Published in at http://dx.doi.org/10.1214/07-AOAS146 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

    Theoretical foundation of 3D Alfvén resonances : normal modes

    Get PDF
    We consider the resonant coupling of fast and Alfvén magnetohydrodynamic (MHD) waves in a 3D equilibrium. Numerical solutions to normal modes (∝ exp(−iωt)) are presented, along with a theoretical framework to interpret them. The solutions we find are fundamentally different from those in 1D and 2D. In 3D there exists an infinite number of possible resonant solutions within a “Resonant Zone," and we show how boundary conditions and locally 2D regions can favor particular solutions. A unique feature of the resonance in 3D is switching between different permissible solutions when the boundary of the Resonant Zone is encountered. The theoretical foundation that we develop relies upon recognizing that in 3D the orientation of the resonant surface will not align in a simple fashion with an equilibrium coordinate. We present a method for generating the Alfvén wave natural frequencies for an arbitrarily oriented Alfvén wave, which requires a careful treatment of scale factors describing the background magnetic field geometry.PostprintPeer reviewe

    The integrity and provenance of religious education : modernism, deconstruction and critical realism.

    Get PDF
    This thesis focuses on contemporary religious education within the state system of England and Wales. It explores the influence upon religious education of epistemology, theological and religious formulations, and educational philosophy in the context of the decline of modernism and concurrent emergence of programmes of post-modernism and critical realism. Within this developing context the question of the ability of religious education to make possible the emergence of authentic religious understanding is asked. In Part One, the provenance of religious education between 1944 and 1988 is identified as being that of the tradition of liberal modernism that grew out of the Enlightenment. The basic dualistic epistemological contours of modernism are identified, and it is shown how these give rise to a liberal experiential-expressive understanding of the nature of religion. In similar fashion, modernism engenders specifically modem forms of educational philosophy. Religious education has elected to work within this modernist provenance, making uncritical assumptions that are dependent upon modem philosophical, religious and educational debate, and as a result is unable to uphold the integrity of its subject matter. In Part Two, the nature of deconstructive post-modem responses to the limitations of modernism are outlined, together with the understanding of the nature of religion that such a reaction produces. It is suggested that the implementation of a programme of religious education within this alternative setting would also fail to do justice to the integrity of religion. In Part Three, the response of critical realism to modernism is set out, and the implications of this for an understanding of the nature of religion are explored. A philosophy of education within critical realism is proposed, together with a revised framework for religious education, one able to uphold the integrity of religion, both in terms of its intrinsic diversity and its intrinsically realistic self-understandin

    Free-living Neoparamoeba perurans depth distribution is mostly uniform in salmon cages, but reshaped by stratification and potentially extreme fish crowding

    Get PDF
    Understanding the spatio-temporal positioning of hosts and their parasites in free-living states is useful in devising methods to diminish parasite encounters in animal production systems. We explored the potential for depth-based control methods of the amoebic gill disease (AGD) agent, Neoparamoeba perurans, in salmon mariculture systems by conducting: (1) depth-stratified N. perurans water sampling surveys in 2 years, and (2) a mensurative experiment comparing depth distributions of N. perurans and salmon hosts in commercial salmon sea-cages. From water sampling mostly at marine salinities, N. perurans abundance (quantitative PCR-derived cells l-1) varied among years, but overall, neither depth, time since freshwater bathing, temperature and salinity were predictors of N. perurans abundance. However, at 1 survey time, depth patterns in N. perurans abundance appeared during strong vertical salinity gradients following rainfall (at 1 site, salinity ranged between 14 and 35 g l-1), with greater numbers of cells below a less saline surface layer. This suggested that salinity mediates N. perurans depth distribution during intermittent halocline development. Fish depth distribution monitoring revealed intense fish crowding, with local swimming densities up to 5 times stocking densities, typically at the surface at night. Simultaneously collected daytime water samples during low levels of fish crowding, with stock scattered amongst upper and lower cage sections, revealed no relationship between N. perurans and fish depth distributions. If intense fish crowding in narrow depth bands leads to high concentrations of N. perurans in cage environments and increased AGD risk, behavioural manipulations that vertically spread fish could be a successful AGD mitigation strategy.publishedVersio

    Smart grid measurement uncertainty : definitional and influence quantity considerations

    Get PDF
    Measurement uncertainty, in general terms, is an expression of the quality of a measurement. It is typically quan- tified by defining the location and spread of the distribution of a hypothetical infinitely large number of measurements of the thing being measured. The Guide to the Expression of Uncertainty in Measurement (GUM) classifies uncertainties according to whether they are evaluated by statistical means or not. The GUM also mentions that an incomplete definition of the measurand can give rise to large uncertainty in the result. For some of the quantities measured in the Smart Grid, it may be that this "definitional uncertainty" could be a major source of problems. Influence quantities may have a bearing on the result of a measurement without being the subject of the measurement. For example, signal harmonics, noise and temperature effects, while not desired as part of a measurement, exist in power system signals being measured, and they have (sometimes significant) effects on the measurement process

    Morgellons disease, illuminating an undefined illness: a case series

    Get PDF
    <p>Abstract</p> <p>Introduction</p> <p>This review of 25 consecutive patients with Morgellons disease (MD) was undertaken for two primary and extremely fundamental reasons. For semantic accuracy, there is only one "proven" MD patient: the child first given that label. The remainder of inclusive individuals adopted the label based on related descriptions from 1544 through 1884, an internet description quoted from Sir Thomas Browne (1674), or was given the label by practitioners using similar sources. Until now, there has been no formal characterization of MD from detailed examination of all body systems. Our second purpose was to differentiate MD from Delusions of Parasitosis (DP), another "informal" label that fit most of our MD patients. How we defined and how we treated these patients depended literally on factual data that would determine outcome. How they were labeled in one sense was irrelevant, except for the confusing conflict rampant in the medical community, possibly significantly skewing treatment outcomes.</p> <p>Case presentation</p> <p>Clinical information was collected from 25 of 30 consecutive self-defined patients with Morgellons disease consisting of laboratory data, medical history and physical examination findings. Abnormalities were quantified and grouped by system, then compared and summarized, but the numbers were too small for more complex mathematical analysis. The quantification of physical and laboratory abnormalities allowed at least the creation of a practical clinical boundary, separating probable Morgellon<it>s</it> from non-Morgellons patients. All the 25 patients studied meet the most commonly used DP definitions.</p> <p>Conclusions</p> <p>These data suggest Morgellons disease can be characterized as a physical human illness with an often-related delusional component in adults. All medical histories support that behavioral aberrancies onset only after physical symptoms. The identified abnormalities include both immune deficiency and chronic inflammatory markers that correlate strongly with immune cytokine excess. The review of 251 current NLM DP references leads us to the possibility that Morgellons disease and DP are grossly truncated labels of the same illness but with the reversal of the cause-effect order. Further, the patients' data suggest that both illnesses have an infectious origin.</p

    The California Planet Survey. I. Four New Giant Exoplanets

    Get PDF
    We present precise Doppler measurements of four stars obtained during the past decade at Keck Observatory by the California Planet Survey (CPS). These stars, namely, HD 34445, HD 126614, HD 13931, and Gl 179, all show evidence for a single planet in Keplerian motion. We also present Doppler measurements from the Hobby-Eberly Telescope (HET) for two of the stars, HD 34445 and Gl 179, that confirm the Keck detections and significantly refine the orbital parameters. These planets add to the statistical properties of giant planets orbiting near or beyond the ice line, and merit follow-up by astrometry, imaging, and space-borne spectroscopy. Their orbital parameters span wide ranges of planetary minimum mass (M sin i = 0.38-1.9 M(Jup)), orbital period (P = 2.87-11.5 yr), semimajor axis (a = 2.1-5.2 AU), and eccentricity (e = 0.02-0.41). HD 34445 b (P = 2.87 yr, M sin i = 0.79 MJup, e = 0.27) is a massive planet orbiting an old, G-type star. We announce a planet, HD 126614 Ab, and an M dwarf, HD 126614 B, orbiting the metal-rich star HD 126614 (which we now refer to as HD 126614 A). The planet, HD 126614 Ab, has minimum mass M sin i = 0.38 MJup and orbits the stellar primary with period P = 3.41 yr and orbital separation a = 2.3 AU. The faint M dwarf companion, HD 126614 B, is separated from the stellar primary by 489 mas (33 AU) and was discovered with direct observations using adaptive optics and the PHARO camera at Palomar Observatory. The stellar primary in this new system, HD 126614 A, has the highest measured metallicity ([ Fe/ H] = + 0.56) of any known planet-bearing star. HD 13931 b (P = 11.5 yr, M sin i = 1.88 MJup, e = 0.02) is a Jupiter analog orbiting a near solar twin. Gl 179 b (P = 6.3 yr, M sin i = 0.82 M(Jup), e = 0.21) is a massive planet orbiting a faint M dwarf. The high metallicity of Gl 179 is consistent with the planet-metallicity correlation among M dwarfs, as documented recently by Johnson & Apps.NSF AST-0702821NASA NNX06AH52GMcDonald Observator

    First NuSTAR Limits on Quiet Sun Hard X-Ray Transient Events

    Get PDF
    We present the first results of a search for transient hard X-ray (HXR) emission in the quiet solar corona with the \textit{Nuclear Spectroscopic Telescope Array} (\textit{NuSTAR}) satellite. While \textit{NuSTAR} was designed as an astrophysics mission, it can observe the Sun above 2~keV with unprecedented sensitivity due to its pioneering use of focusing optics. \textit{NuSTAR} first observed quiet Sun regions on 2014 November 1, although out-of-view active regions contributed a notable amount of background in the form of single-bounce (unfocused) X-rays. We conducted a search for quiet Sun transient brightenings on time scales of 100 s and set upper limits on emission in two energy bands. We set 2.5--4~keV limits on brightenings with time scales of 100 s, expressed as the temperature T and emission measure EM of a thermal plasma. We also set 10--20~keV limits on brightenings with time scales of 30, 60, and 100 s, expressed as model-independent photon fluxes. The limits in both bands are well below previous HXR microflare detections, though not low enough to detect events of equivalent T and EM as quiet Sun brightenings seen in soft X-ray observations. We expect future observations during solar minimum to increase the \textit{NuSTAR} sensitivity by over two orders of magnitude due to higher instrument livetime and reduced solar background.Comment: 11 pages, 7 figures; accepted for publication in The Astrophysical Journa
    corecore