558 research outputs found

    Abundant variation in microsatellites of the parasitic nematode Trichostrongylus tenuis and linkage to a tandem repeat

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    An understanding of how genes move between and within populations of parasitic nematodes is important in combating the evolution and spread of anthelmintic resistance. Much has been learned by studying mitochondrial DNA markers, but autosomal markers such as microsatellites have been applied to only a few nematode species, despite their many advantages for studying gene flow in eukaryotes. Here, we describe the isolation of 307 microsatellites from Trichostrongylus tenuis, an intestinal nematode of red grouse. High levels of variation were revealed at sixteen microsatellite loci (including three sex-lined loci) in 111 male T. tenuis nematodes collected from four hosts at a single grouse estate in Scotland (average He = 0.708; mean number of alleles = 12.2). A population genetic analysis detected no deviation from panmixia either between (F(ST) = 0.00) or within hosts (F(IS) = 0.015). We discuss the feasibility of developing microsatellites in parasitic nematodes and the problem of null alleles. We also describe a novel 146-bp repeat element, TteREP1, which is linked to two-thirds of the microsatellites sequenced and is associated with marker development failure. The sequence of TteREP1 is related to the TcREP-class of repeats found in several other trichostrongyloid species including Trichostrongylus colubriformis and Haemonchus contortus

    An in-situ approach for preparing atom probe tomography specimens by xenon plasma-focused ion beam

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    A method for the rapid preparation of atom probe tomography (APT) needles using a xenon plasma-focused ion beam (FIB) instrument is presented and demonstrated on a test sample of Ti-6Al-4V alloy. The method requires significantly less operator input than the standard lift-out protocol, is site-specific and produces needles with minimal ion-beam damage; electron microscopy indicated the needle's surface amorphised/oxidised region to be less than 2 nm thick. The resulting needles were routinely analysable by APT, confirming the expected microstructure and showing negligible Xe contamination

    Correction of EELS dispersion non-uniformities for improved chemical shift analysis

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    We outline a simple routine to correct for non-uniformities in the energy dispersion of a post-column electron energy-loss spectrometer for use in scanning transmission electron microscopy. We directly measure the dispersion and its variations by sweeping a spectral feature across the full camera to produce a calibration that can be used to linearize datasets post-acquisition, without the need for reference materials. The improvements are illustrated using core excitation electron energy-loss spectroscopy (EELS) spectra collected from NiO and diamond samples. The calibration is rapid and will be of use in all EELS analysis, particularly in assessments of the chemical states of materials via the chemical shift of core-loss excitations

    The magnetic field influence on magnetostructural phase transition in Ni2.19Mn0.81Ga

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    Magnetic properties of a polycrystalline alloy Ni2.19_{2.19}Mn0.81_{0.81}Ga, which undergoes a first-order magnetostructural phase transition from cubic paramagnetic to tetragonal ferromagnetic phase, are studied. Hysteretic behavior of isothermal magnetization M(H)M(H) has been observed in a temperature interval of the magnetostructural transition in magnetic fields from 20 to 100 kOe. Temperature dependencies of magnetization MM, measured in magnetic fields H=400H = 400 and 60 kOe, indicate that the temperature of the magnetostructural transition increases with increasing magnetic field.Comment: Presented at the Second Moscow International Symposium on Magnetism (Moscow-2002

    Denial at the top table: status attributions and implications for marketing

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    Senior marketing management is seldom represented on the Board of Directors nowadays, reflecting a deteriorating status of the marketing profession. We examine some of the key reasons for marketing’s demise, and discuss how the status of marketing may be restored by demonstrating the value of marketing to the business community. We attribute marketing’s demise to several related key factors: narrow typecasting, marginalisation and limited involvement in product development, questionable marketing curricula, insensitivity toward environmental change, questionable professional standards and roles, and marketing’s apparent lack of accountability to CEOs. Each of these leads to failure to communicate, create, or deliver value within marketing. We argue that a continued inability to deal with marketing’s crisis of representation will further erode the status of the discipline both academically and professionally

    Tune in to your emotions: a robust personalized affective music player

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    The emotional power of music is exploited in a personalized affective music player (AMP) that selects music for mood enhancement. A biosignal approach is used to measure listeners’ personal emotional reactions to their own music as input for affective user models. Regression and kernel density estimation are applied to model the physiological changes the music elicits. Using these models, personalized music selections based on an affective goal state can be made. The AMP was validated in real-world trials over the course of several weeks. Results show that our models can cope with noisy situations and handle large inter-individual differences in the music domain. The AMP augments music listening where its techniques enable automated affect guidance. Our approach provides valuable insights for affective computing and user modeling, for which the AMP is a suitable carrier application

    Robust statistics towards detection of the 21 cm signal from the Epoch of Reionization

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    © 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. We explore methods for robust estimation of the 21 cm signal from the Epoch of Reionization (EoR). A Kernel Density Estimator (KDE) is introduced for measuring the spatial temperature fluctuation power spectrum from the EoR. The KDE estimates the underlying probability distribution function of fluctuations as a function of spatial scale, and contains different systematic biases and errors to the typical approach to estimating the fluctuation power spectrum. Extraction of histograms of visibilities allows moments analysis to be used to discriminate foregrounds from 21 cm signal and thermal noise. We use the information available in the histograms, along with the statistical dis-similarity of foregrounds from two independent observing fields, to robustly separate foregrounds from cosmological signal, while making no assumptions about the Gaussianity of the signal. Using two independent observing fields to robustly discriminate signal from foregrounds is crucial for the analysis presented in this paper. We apply the techniques to 13 h of Murchison Widefield Array EoR data over two observing fields. We compare the output to that obtained with a comparative power spectrum estimation method, and demonstrate the reduced foreground contamination using this approach. Using the second moment obtained directly from the KDE distribution functions yields a factor of 2-3 improvement in power for k < 0.3 h Mpc-1 compared with a matched delay space power estimator, while weighting data by additional statistics does not offer significant improvement beyond that available for thermal noise-only weights

    The anti-NGF antibody muMab 911 both prevents and reverses pain behaviour and subchondral osteoclast numbers in a rat model of osteoarthritis pain

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    Objective: Nerve growth factor (NGF) has a pivotal role in peripheral hyperalgesia and inflammation; anti-NGF antibodies attenuate pain responses in inflammatory pain models, and in people with osteoarthritis (OA) or low back pain. The aim of this study was to characterise the peripheral mechanisms contributing to the analgesic effects of anti-NGF antibody treatment in an established model of joint pain, which mimics key clinical features of OA. Design: Effects of preventative vs therapeutic treatment with an anti-NGF antibody (monoclonal antibody 911: muMab 911 (10 mg/kg, s.c.)) on pain behaviour (weight bearing asymmetry and hindpaw withdrawal thresholds (PWT)), cartilage damage, synovitis and numbers of subchondral osteoclasts were investigated in the monosodium iodoacetate (MIA) model. Potential direct effects of NGF on receptor activator of nuclear factor kappa-B ligand (RANKL) mediated osteoclastogenesis were investigated in cultured human osteoclasts. Results: Intra-articular MIA injection resulted in significant pain behaviour, cartilage damage, synovitis and increased numbers of subchondral osteoclasts. Both preventative and therapeutic treatment with muMab 911 significantly prevented, or reversed, MIA-induced pain behaviour, but did not alter cartilage or synovial pathology quantified at the end of the treatment period. NGF did not facilitate RANKL driven osteoclast differentiation in vitro, but preventative or therapeutic muMab 911 reduced numbers of TRAP positive osteoclasts in the subchondral bone. Conclusions: We demonstrate that anti-NGF antibody treatment attenuates OA pain behaviour despite permitting cartilage damage and synovitis. Indirec
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