Orthogonal Block Structure and Uniformly Best Linear Unbiased Estimators

Models with orthogonal block structure, OBS, have variance covariance matrices that are linear combinations [...]info:eu-repo/semantics/publishedVersio

Magneto-optic superlattice thin films: Fabrication, structural and magnetic characterization

During this quarter studies were extended to determine the electronic contribution to the perpendicular interface anisotropy in Co-based multilayers. Using in situ Kerr effect measurements, the influences of different transition metals (TM = Ag, Au, Cu, and Pd) on the magnetic properties of single-crystal Co films grown on Pd (111) and Au (111) surfaces are investigated. Last quarter the discovery of a large peak in the perpendicular anisotropy when approximately one monolayer of Cu or Ag is deposited on the Co surface was reported. We now have added a computer-controlled stepper-motor drive to our MBE sample transfer mechanism. The motor allows us to move the sample at a constant velocity from behind a shutter during deposition. The film, therefore, is deposited as a wedge with a linear variation of thickness across the substrate. In this way, a continuous range of coverage on a single sample is studied. The stepper motor also provides the necessary control for precisely positioning the sample in the laser beam for Kerr effect measurements at the different coverages

Paratuberculosis sero-status and milk production, SCC and calving interval in Irish dairy herds

The objective of this study was to investigate the impact of paratuberculosis sero-status on milk yield, fat, protein, somatic cell count and calving interval in Irish dairy herds. Serum from all animals over 12 months of age (n = 2,602) in 34 dairy herds was tested for antibodies to Mycobacterium avium subsp. paratuberculosis using an ELISA. Herds were categorised by sero-status into positive, non-negative and negative, where a positive herd contained two or more positive cows, a non-negative herd contained only one positive cow and a negative herd contained no positive cows. Data at animal, parity and herd-level were analysed by multiple regression using general linear models. Positive herds (mean herd size = 129 cows) and non-negative herds (81 cows) were larger than negative herds (72 cows) (P < 0.01). Negative herds had the highest economic breeding index (EBI), while positive herds had the highest estimated breeding value (EBV) for milk yield. There was no significant effect of paratuberculosis sero-status at animal, parity or herd-level on milk yield, milk fat or protein production, somatic cell count score (SCCS) or calving interval. Negative herds tended to have a lower SCCS than positive and nonnegative herds (P = 0.087). This study only examined the effects of paratuberculosis sero-status but did not examine the clinical effects of Johne's disease at the farm or dairy industry levels

An Experimental Exploration of the QCD Phase Diagram: The Search for the Critical Point and the Onset of De-confinement

The QCD phase diagram lies at the heart of what the RHIC Physics Program is all about. While RHIC has been operating very successfully at or close to its maximum energy for almost a decade, it has become clear that this collider can also be operated at lower energies down to 5 GeV without extensive upgrades. An exploration of the full region of beam energies available at the RHIC facility is imperative. The STAR detector, due to its large uniform acceptance and excellent particle identification capabilities, is uniquely positioned to carry out this program in depth and detail. The first exploratory beam energy scan (BES) run at RHIC took place in 2010 (Run 10), since several STAR upgrades, most importantly a full barrel Time of Flight detector, are now completed which add new capabilities important for the interesting physics at BES energies. In this document we discuss current proposed measurements, with estimations of the accuracy of the measurements given an assumed event count at each beam energy.Comment: 59 pages, 78 figure

Promoting Evidence-based Veterinary Medicine through the online resource ‘EBVM Learning’: User feedback

‘EBVM Learning’ is a freely available resource created in 2015 by an international team with the support of RCVS Knowledge. The resource comprises a series of online modules teaching the fundamental concepts of evidence-based veterinary medicine (EBVM) (Ask, Acquire, Appraise, Apply & Assess) supported by case studies, exercises, worked examples and quizzes. The aim of the current study (undertaken in 2019) was to review ‘EBVM Learning’ to ensure its ongoing relevance and usefulness to the range of learners engaged in EBVM. Feedback was gathered from stakeholder groups using website statistics and feedback forms, a survey and semi-structured interviews to provide a combination of quantitative and qualitative data.Website statistics revealed an international audience and a steady increase in visitors exceeding 1,000 per month in August 2020. Feedback via the online form (n=35) and survey (n=71) indicated that the resource was well structured, with an appropriate level and amount of content, useful examples and quizzes and the majority of respondents would use it again. Semi-structured interviews of educators (n=5) and veterinarians (n=8) identified three themes: features of the ‘EBVM Learning’ resource (strengths, suggestions for improvement), embedding the resource in education (undergraduate, postgraduate) and promoting EBVM (challenges, motivation for engagement). At a project team workshop the results were used to plan updates to the existing content and to identify new ways to promote learning and engagement. An updated version of ‘EBVM Learning’ was developed.‘EBVM Learning’ is helping to produce the next generation of evidence-based practitioners and enabling to engage in the concepts of EBVM as part of their clinical practice

Synaptic Transmission from Horizontal Cells to Cones Is Impaired by Loss of Connexin Hemichannels

In the vertebrate retina, horizontal cells generate the inhibitory surround of bipolar cells, an essential step in contrast enhancement. For the last decades, the mechanism involved in this inhibitory synaptic pathway has been a major controversy in retinal research. One hypothesis suggests that connexin hemichannels mediate this negative feedback signal; another suggests that feedback is mediated by protons. Mutant zebrafish were generated that lack connexin 55.5 hemichannels in horizontal cells. Whole cell voltage clamp recordings were made from isolated horizontal cells and cones in flat mount retinas. Light-induced feedback from horizontal cells to cones was reduced in mutants. A reduction of feedback was also found when horizontal cells were pharmacologically hyperpolarized but was absent when they were pharmacologically depolarized. Hemichannel currents in isolated horizontal cells showed a similar behavior. The hyperpolarization-induced hemichannel current was strongly reduced in the mutants while the depolarization-induced hemichannel current was not. Intracellular recordings were made from horizontal cells. Consistent with impaired feedback in the mutant, spectral opponent responses in horizontal cells were diminished in these animals. A behavioral assay revealed a lower contrast-sensitivity, illustrating the role of the horizontal cell to cone feedback pathway in contrast enhancement. Model simulations showed that the observed modifications of feedback can be accounted for by an ephaptic mechanism. A model for feedback, in which the number of connexin hemichannels is reduced to about 40%, fully predicts the specific asymmetric modification of feedback. To our knowledge, this is the first successful genetic interference in the feedback pathway from horizontal cells to cones. It provides direct evidence for an unconventional role of connexin hemichannels in the inhibitory synapse between horizontal cells and cones. This is an important step in resolving a long-standing debate about the unusual form of (ephaptic) synaptic transmission between horizontal cells and cones in the vertebrate retina

A Positive Feedback Synapse from Retinal Horizontal Cells to Cone Photoreceptors

Cone photoreceptors and horizontal cells (HCs) have a reciprocal synapse that underlies lateral inhibition and establishes the antagonistic center-surround organization of the visual system. Cones transmit to HCs through an excitatory synapse and HCs feed back to cones through an inhibitory synapse. Here we report that HCs also transmit to cone terminals a positive feedback signal that elevates intracellular Ca2+ and accelerates neurotransmitter release. Positive and negative feedback are both initiated by AMPA receptors on HCs, but positive feedback appears to be mediated by a change in HC Ca2+, whereas negative feedback is mediated by a change in HC membrane potential. Local uncaging of AMPA receptor agonists suggests that positive feedback is spatially constrained to active HC-cone synapses, whereas the negative feedback signal spreads through HCs to affect release from surrounding cones. By locally offsetting the effects of negative feedback, positive feedback may amplify photoreceptor synaptic release without sacrificing HC-mediated contrast enhancement

Gaia Data Release 1: Open cluster astrometry: performance, limitations, and future prospects

Context. The first Gaia Data Release contains the Tycho-Gaia Astrometric Solution (TGAS). This is a subset of about 2 million stars for which, besides the position and photometry, the proper motion and parallax are calculated using Hipparcos and Tycho-2 positions in 1991.25 as prior information.Aims. We investigate the scientific potential and limitations of the TGAS component by means of the astrometric data for open clusters.Methods. Mean cluster parallax and proper motion values are derived taking into account the error correlations within the astrometric solutions for individual stars, an estimate of the internal velocity dispersion in the cluster, and, where relevant, the effects of the depth of the cluster along the line of sight. Internal consistency of the TGAS data is assessed.Results. Values given for standard uncertainties are still inaccurate and may lead to unrealistic unit-weight standard deviations of least squares solutions for cluster parameters. Reconstructed mean cluster parallax and proper motion values are generally in very good agreement with earlier HIPPARCOS-based determination, although the Gaia mean parallax for the Pleiades is a significant exception. We have no current explanation for that discrepancy. Most clusters are observed to extend to nearly 15 pc from the cluster centre, and it will be up to future Gaia releases to establish whether those potential cluster-member stars are still dynamically bound to the clusters.Conclusions. The Gaia DR1 provides the means to examine open clusters far beyond their more easily visible cores, and can provide membership assessments based on proper motions and parallaxes. A combined HR diagram shows the same features as observed before using the HIPPARCOS data, with clearly increased luminosities for older A and F dwarfs

Assessment of coagulated and non-coagulated ASB performance used to treat Pinus radiata sulfite pulp and paper mill effluent by resin fractionation and HPSEC techniques

Resin fractionation (XAD-8), high performance size exclusion chromatography (HPSEC) UV260 and 280 nm and HPSEC-fluorescence techniques were used to characterise very hydrophobic acid (VHA) and slightly hydrophobic to hydrophilic (Non-VHA) compounds in treated wastewater from a Pinus radiata (Sulfite) pulp and paper mill that incorporates aerated stabilisation basins (ASBs). The use of these techniques enabled a rigorous evaluation of ASB performance with coagulation pre-treatment, using laboratory-based simulation studies and a full-scale ASB. The laboratory scale ASB treatment comprised two parallel sets of three tanks (A and B) that were operated over three hydraulic retention times (HRTs) of 84days. Simulations were based on the full-scale HRT. The influent used for both simulations was post-coagulated pulp mill mixed with paper mill wastewater (1:2). Sludge collected from the full scale ASB pond system was added to the tanks of both simulations for inoculation with indigenous microorganisms. In addition, settled sludge collected after coagulation of pulp mill wastewaters was added to simulation B to investigate the effects of alum flocculated material. Coagulation pre-treatment with alum removed HMW compounds (∼3-8kDa), and alum sludge addition to further simulate potential long-term application of coagulation as a pre-treatment step prior to ASB resulted in further removal of HMW components. SUVA and specific colour of wastewaters increased during ASB treatment with the least colour formation occurring in Simulation B. There were no significant differences in DOC, UV-visible absorbance and total relative abundance of VHA and Non-VHA compounds between pre-coagulated (A and B) and untreated waters following ASB, except for a HMW of VHA component of ∼1700Da, which was attributed to the significant colour development in the treated wastewater. The use of these analytical tools provided insight on the fate and transformation of recalcitrant organic compounds typically present in pulp and paper mill effluents. © 2012 Elsevier B.V.Rosmala Lewis, John A. van Leeuwen, Christopher W.K. Chow, Andrew Everson, David M. Lewi