1,006 research outputs found

    A new species of mudfish, Neochanna (Teleostei: Galaxidae), from northern New Zealand

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    A new species of mudfish, Neochanna, is described from Northland. Neochanna heleios n.sp. is known from only three ephemeral wetland sites on the Kerikeri volcanic plateau and is abundant only at the type locality. The new species has a head resembling that of the brown mudfish, Neochanna apoda, and a caudal region resembling that of the black mudfish, Neochanna diversus. It can be distinguished from all Neochanna species in having a reduced number of principal caudal fin rays (13 or less). Morphometric and meristic comparisons with N. apoda and N. diversus are provided

    UK managers’ conceptions of training and development

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    Purpose: The paper commences with a review of the practical and theoretical distinctions between training and development in the organizational psychology and HRD literature perspectiveto investigate the conceptual distinctions between training and development. We then investigate how managers responsible for the training and development function conceptualise these activities in practice, the factors which guide their decision making, how they evaluate the outcomes and they extent they perceive a relationship between training and development. Design/methodology/approach: Interview data from 26 UK managers were coded using Template. Findings: Managers conceptualisations of training and development vary. Formal training is prioritised due to a perceived more tangible demonstrable return on investment. Perceived success in training focuses on improvements to job related skills whereas success outcomes for development are more varied and difficult to measure. Managers consider training and development more valuable when combined. Implications for research: The findings highlight the need for further process driven research to understand the interrelationship between training and development and the need to develop methods that can be used by organisations to evaluate both. These need to go beyond those currently in use and include both qualitative and quantitative measures. Implications for practice: Managers may take a more proactive and directive role in facilitating development than the literature suggests, thus their role needs to be more actively considered in HRD learning strategies. Originality/value: This is one of the first qualitative studies to explore the conceptualisations of managers responsible for training and development, highlighting the interrelationship between training and development and the factors guiding decisions regarding these activitie

    Ultrastructure and complex polar architecture of the human pathogen Campylobacter jejuni

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    Campylobacter jejuni is one of the most successful food-borne human pathogens. Here we use electron cryotomography to explore the ultrastructure of C. jejuni cells in logarithmically growing cultures. This provides the first look at this pathogen in a near-native state at macromolecular resolution (∼5 nm). We find a surprisingly complex polar architecture that includes ribosome exclusion zones, polyphosphate storage granules, extensive collar-shaped chemoreceptor arrays, and elaborate flagellar motors

    Distribution and abundance of fish and crayfish in a Waikato stream in relation to basin area

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    The aim of this study was to relate the longitudinal distribution of fish and crayfish to increasing basin area and physical site characteristics in the Mangaotama Stream, Waikato region, North Island, New Zealand. Fish and crayfish were captured with two-pass removal electroshocking at 11 sites located in hill-country with pasture, native forest, and mixed land uses within the 21.6 km2 basin. Number of fish species and lineal biomass of fish increased with increasing basin area, but barriers to upstream fish migration also influenced fish distribution; only climbing and non-migratory species were present above a series of small waterfalls. Fish biomass increased in direct proportion to stream width, suggesting that fish used much of the available channel, and stream width was closely related to basin area. Conversely, the abundance of crayfish was related to the amount of edge habitat, and therefore crayfish did not increase in abundance as basin area increased. Densities of all fish species combined ranged from 17 to 459 fish 100 m-2, and biomass ranged from 14 to 206 g m-2. Eels dominated the fish assemblages, comprising 85-100% of the total biomass; longfinned eels the majority of the biomass at most sites. Despite the open access of the lower sites to introduced brown trout, native species dominated all the fish communities sampled

    Fluctuations and differential contraction during regeneration of Hydra vulgaris tissue toroids

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    We studied regenerating bilayered tissue toroids dissected from Hydra vulgaris polyps and relate our macroscopic observations to the dynamics of force-generating mesoscopic cytoskeletal structures. Tissue fragments undergo a specific toroid-spheroid folding process leading to complete regeneration towards a new organism. The time scale of folding is too fast for biochemical signalling or morphogenetic gradients which forced us to assume purely mechanical self-organization. The initial pattern selection dynamics was studied by embedding toroids into hydro-gels allowing us to observe the deformation modes over longer periods of time. We found increasing mechanical fluctuations which break the toroidal symmetry and discuss the evolution of their power spectra for various gel stiffnesses. Our observations are related to single cell studies which explain the mechanical feasibility of the folding process. In addition, we observed switching of cells from a tissue bound to a migrating state after folding failure as well as in tissue injury. We found a supra-cellular actin ring assembled along the toroid's inner edge. Its contraction can lead to the observed folding dynamics as we could confirm by finite element simulations. This actin ring in the inner cell layer is assembled by myosin- driven length fluctuations of supra-cellular {\alpha}-actin structures (myonemes) in the outer cell-layer.Comment: 19 pages and 8 figures, submitted to New Journal of Physic

    Inverse Transport Theory of Photoacoustics

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    We consider the reconstruction of optical parameters in a domain of interest from photoacoustic data. Photoacoustic tomography (PAT) radiates high frequency electromagnetic waves into the domain and measures acoustic signals emitted by the resulting thermal expansion. Acoustic signals are then used to construct the deposited thermal energy map. The latter depends on the constitutive optical parameters in a nontrivial manner. In this paper, we develop and use an inverse transport theory with internal measurements to extract information on the optical coefficients from knowledge of the deposited thermal energy map. We consider the multi-measurement setting in which many electromagnetic radiation patterns are used to probe the domain of interest. By developing an expansion of the measurement operator into singular components, we show that the spatial variations of the intrinsic attenuation and the scattering coefficients may be reconstructed. We also reconstruct coefficients describing anisotropic scattering of photons, such as the anisotropy coefficient g(x)g(x) in a Henyey-Greenstein phase function model. Finally, we derive stability estimates for the reconstructions

    Alzheimer\u27s, angiotensin IV and an aminopeptidase

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    The angiotensin AT4 receptor was originally defined as the specific, high affinity binding site for the hexapeptide angiotensin IV (Ang IV). Subsequently, the peptide LVV-hemorphin 7 was also demonstrated to be a bioactive ligand of the AT4 receptor. Central administration of Ang IV or LVV-hemorphin 7 (LVV-H7) markedly enhances learning and memory in normal rodents and reverse memory deficits observed in animal models of amnesia. The high affinity binding site has a broad distribution in the brain including areas such as the hippocmapus that are involved in memory processing. The high affinity Ang IV binding site (AT4 receptor) has been identified as the transmembrane enzyme, insulin-regulated membrane aminopeptidase (IRAP). Insulin-regulated aminopeptidase is a type II integral membrane spanning protein belonging to the M1 family of aminopeptidases and in insulin-responsive cells colocalizes with GLUT4 in specific intra-cellular vesicles. Both Ang IV and LVV-H7 are competitive inhibitors of IRAP catalytic activity and are not substrates of the enzyme.<br /
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