1,344 research outputs found

    A 2.5% measurement of the growth rate from small-scale redshift space clustering of SDSS-III CMASS galaxies

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    We perform the first fit to the anisotropic clustering of SDSS-III CMASS DR10 galaxies on scales of ~ 0.8 - 32 Mpc/h. A standard halo occupation distribution model evaluated near the best fit Planck LCDM cosmology provides a good fit to the observed anisotropic clustering, and implies a normalization for the peculiar velocity field of M ~ 2 x 10^13 Msun/h halos of f*sigma8(z=0.57) = 0.450 +/- 0.011. Since this constraint includes both quasi-linear and non-linear scales, it should severely constrain modified gravity models that enhance pairwise infall velocities on these scales. Though model dependent, our measurement represents a factor of 2.5 improvement in precision over the analysis of DR11 on large scales, f*sigma8(z=0.57) = 0.447 +/- 0.028, and is the tightest single constraint on the growth rate of cosmic structure to date. Our measurement is consistent with the Planck LCDM prediction of 0.480 +/- 0.010 at the ~1.9 sigma level. Assuming a halo mass function evaluated at the best fit Planck cosmology, we also find that 10% of CMASS galaxies are satellites in halos of mass M ~ 6 x 10^13 Msun/h. While none of our tests and model generalizations indicate systematic errors due to an insufficiently detailed model of the galaxy-halo connection, the precision of these first results warrant further investigation into the modeling uncertainties and degeneracies with cosmological parameters.Comment: 24 pages, 20 figures, submitted to MNRAS. v2 is 27 pages, 23 figures, accepted by MNRA

    Pharmacist Behavior Changes Following a Medication Counseling Training Program Targeting Teach-Back and Plain Language

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    Purpose: To evaluate whether active learning-based training in teach-back and plain language (TBPL) techniques can lead to observable changes to patient-centered practices in pharmacist-patient counseling. Methods: All pharmacists in direct patient care roles, inpatient and outpatient, were required to complete a didactic module and a workshop / webinar or small group training. The workshop / webinar and small group modalities incorporated elements of adult education theory. Following completion, pharmacists were surveyed to assess their ability, confidence and commitment to incorporating TBPL techniques into practice. Evaluation of pharmacist-patient counseling was completed pre- and post- training through direct observation. Student pharmacists were trained to evaluate pharmacists’ consultations on patients with ≥2 new medications. Students recorded completeness rates for 39 communication techniques. Results: One-hundred and eighteen pharmacists completed the TBPL training program and 59 pharmacists completed an evaluation. A total of 84 direct observations were completed (40 pre-training and 44 post-training). Skills improved included: using plain language (p Conclusion: Implementing a TBPL training program improved observable pharmacist-patient consultation skills. This approach is replicable and could be utilized as a model for other competencies.   Type: Original Researc

    Improving Reliability of Subject-Level Resting-State fMRI Parcellation with Shrinkage Estimators

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    A recent interest in resting state functional magnetic resonance imaging (rsfMRI) lies in subdividing the human brain into anatomically and functionally distinct regions of interest. For example, brain parcellation is often used for defining the network nodes in connectivity studies. While inference has traditionally been performed on group-level data, there is a growing interest in parcellating single subject data. However, this is difficult due to the low signal-to-noise ratio of rsfMRI data, combined with typically short scan lengths. A large number of brain parcellation approaches employ clustering, which begins with a measure of similarity or distance between voxels. The goal of this work is to improve the reproducibility of single-subject parcellation using shrinkage estimators of such measures, allowing the noisy subject-specific estimator to "borrow strength" in a principled manner from a larger population of subjects. We present several empirical Bayes shrinkage estimators and outline methods for shrinkage when multiple scans are not available for each subject. We perform shrinkage on raw intervoxel correlation estimates and use both raw and shrinkage estimates to produce parcellations by performing clustering on the voxels. Our proposed method is agnostic to the choice of clustering method and can be used as a pre-processing step for any clustering algorithm. Using two datasets---a simulated dataset where the true parcellation is known and is subject-specific and a test-retest dataset consisting of two 7-minute rsfMRI scans from 20 subjects---we show that parcellations produced from shrinkage correlation estimates have higher reliability and validity than those produced from raw estimates. Application to test-retest data shows that using shrinkage estimators increases the reproducibility of subject-specific parcellations of the motor cortex by up to 30%.Comment: body 21 pages, 11 figure

    Proposed mechanisms of tau: relationships to traumatic brain injury, Alzheimer’s disease, and epilepsy

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    Traumatic brain injury (TBI), Alzheimer’s disease (AD), and epilepsy share proposed mechanisms of injury, including neuronal excitotoxicity, cascade signaling, and activation of protein biomarkers such as tau. Although tau is typically present intracellularly, in tauopathies, phosphorylated (p-) and hyper-phosphorylated (hp-) tau are released extracellularly, the latter leading to decreased neuronal stability and neurofibrillary tangles (NFTs). Tau cleavage at particular sites increases susceptibility to hyper-phosphorylation, NFT formation, and eventual cell death. The relationship between tau and inflammation, however, is unknown. In this review, we present evidence for an imbalanced endoplasmic reticulum (ER) stress response and inflammatory signaling pathways resulting in atypical p-tau, hp-tau and NFT formation. Further, we propose tau as a biomarker for neuronal injury severity in TBI, AD, and epilepsy. We present a hypothesis of tau phosphorylation as an initial acute neuroprotective response to seizures/TBI. However, if the underlying seizure pathology or TBI recurrence is not effectively treated, and the pathway becomes chronically activated, we propose a “tipping point” hypothesis that identifies a transition of tau phosphorylation from neuroprotective to injurious. We outline the role of amyloid beta (Aβ) as a “last ditch effort” to revert the cell to programmed death signaling, that, when fails, transitions the mechanism from injurious to neurodegenerative. Lastly, we discuss targets along these pathways for therapeutic intervention in AD, TBI, and epilepsy

    Tensile Cervical Facet Capsule Ligament Mechanics: Failure and Subfailure Responses in the Rat

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    Clinical, epidemiological, and biomechanical studies suggest the involvement of the cervical facet joint in neck pain. Mechanical studies have suggested the facet capsular ligament to be at risk for subfailure tensile injury during whiplash kinematics of the neck. Ligament mechanical properties can be altered by subfailure injury and such loading can induce cellular damage. However, at present, there is no clear understanding of the physiologic context of subfailure facet capsular ligament injury and mechanical implications for whiplash-related pain. Therefore, this study aimed to define a relationship between mechanical properties at failure and a subfailure condition associated with pain for tension in the rat cervical facet capsular ligament. Tensile failure studies of the C6/C7 rat cervical facet capsular ligament were performed using a customized vertebral distraction device. Force and displacement at failure were measured and stiffness and energy to failure were calculated. Vertebral motions and ligament deformations were tracked and maximum principal strains and their directions were calculated. Mean tensile force at failure (2.96±0.69 N) was significantly greater (p\u3c0.005) than force at subfailure (1.17±0.48 N). Mean ligament stiffness to failure was 0.75±0.27 N/mm. Maximum principal strain at failure (41.3±20.0%) was significantly higher (p=0.003) than the corresponding subfailure value (23.1±9.3%). This study determined that failure and a subfailure painful condition were significantly different in ligament mechanics and findings provide preliminary insight into the relationship between mechanics and pain physiology for this ligament. Together with existing studies, these findings offer additional considerations for defining mechanical thresholds for painful injuries

    Forage grasses with lower uptake of casesium and strontium could provide 'safer' crops for radiologically contaminated areas

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    Substitution of a species or cultivar with higher uptake of an element by one with lower uptake has been proposed as a remediation strategy following accidental releases of radioactivity. However, despite the importance of pasture systems for radiological dose, species/cultivar substitution has not been thoroughly investigated for forage grasses. 397 cultivars from four forage grass species; hybrid ryegrass (Lolium perenne L. x Lolium multiflorum Lam.), perennial ryegrass (Lolium perenne L.), Italian ryegrass (Lolium multiflorum Lam.) and tall fescue (Festuca arundinacea Shreb.); were sampled from 19 field-based breeding experiments in Aberystwyth and Edinburgh (UK) in spring 2013 and analysed for caesium (Cs) and strontium (Sr) concentrations. In order to calculate concentration ratios (CRs; the concentration of an element in a plant in relation to the concentration in the soil), soils from the experiments were also analysed to calculate extractable concentrations of Cs and Sr. To test if cultivars have consistently low Cs and Sr concentration ratios, 17 hybrid ryegrass cultivars were sampled from both sites again in summer 2013 and spring and summer 2014. Tall fescue cultivars had lower Cs and Sr CRs than the other species. Three of the selected 17 hybrid ryegrass cultivars had consistently low Cs CRs, two had consistently low Sr CRs and one had consistently low Cs and Sr CRs. Cultivar substitution could reduce Cs CRs by up to 14-fold and Sr CRs by 4-fold in hybrid ryegrass. The identification of species and cultivars with consistently low CRs suggests that species or cultivar substitution could be an effective remediation strategy for contaminated areas

    Connecting massive galaxies to dark matter halos in BOSS - I. Is galaxy color a stochastic process in high-mass halos?

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    We use subhalo abundance matching (SHAM) to model the stellar mass function (SMF) and clustering of the Baryon Oscillation Spectroscopic Survey (BOSS) "CMASS" sample at z0.5z\sim0.5. We introduce a novel method which accounts for the stellar mass incompleteness of CMASS as a function of redshift, and produce CMASS mock catalogs which include selection effects, reproduce the overall SMF, the projected two-point correlation function wpw_{\rm p}, the CMASS dn/dzdn/dz, and are made publicly available. We study the effects of assembly bias above collapse mass in the context of "age matching" and show that these effects are markedly different compared to the ones explored by Hearin et al. (2013) at lower stellar masses. We construct two models, one in which galaxy color is stochastic ("AbM" model) as well as a model which contains assembly bias effects ("AgM" model). By confronting the redshift dependent clustering of CMASS with the predictions from our model, we argue that that galaxy colors are not a stochastic process in high-mass halos. Our results suggest that the colors of galaxies in high-mass halos are determined by other halo properties besides halo peak velocity and that assembly bias effects play an important role in determining the clustering properties of this sample.Comment: 22 pages. Appendix. B added. Matches the version accepted by MNRAS. Mock galaxy catalog and HOD table are available at http://www.massivegalaxies.co

    The Reflective Fostering Programme fidelity rating scale: development and inter-rater reliability

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    Purpose: The purpose of this study is to describe the development of the 14-item reflective fostering fidelity rating (RFFR), an observational rating system to evaluate model fidelity of group facilitators in the Reflective Fostering Programme (RFP), a mentalisation-based psychoeducation programme to support foster carers. The authors assess usability, dimensionality, inter-rater reliability and discriminative ability of the RFFR. Design/methodology/approach: Eighty video clip extracts documenting 20 RFP sessions were independently rated by four raters using the RFFR. The dimensionality of the RFFR was assessed using principal components analysis. Inter-rater agreement was assessed using the intra-class correlation coefficient. Findings: The proportion of missing ratings was low at 2.8%. A single principal component summarised over 90% of the variation in ratings for each rater. The inter-rater reliability of individual item ratings was poor-to-moderate, but a summary score had acceptable inter-rater reliability. The authors present evidence that the RFFR can distinguish RFP sessions that differ in treatment fidelity. Originality/value: To the best of the authors’ knowledge, this is the first investigation and report of the RFFR’s validity in assessing the programme fidelity of the RFP. The paper concludes that the RFFR is an appropriate rating measure for treatment fidelity of the RFP and useful for the purposes of both quality control and supervision

    Simulating Hamiltonians in Quantum Networks: Efficient Schemes and Complexity Bounds

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    We address the problem of simulating pair-interaction Hamiltonians in n node quantum networks where the subsystems have arbitrary, possibly different, dimensions. We show that any pair-interaction can be used to simulate any other by applying sequences of appropriate local control sequences. Efficient schemes for decoupling and time reversal can be constructed from orthogonal arrays. Conditions on time optimal simulation are formulated in terms of spectral majorization of matrices characterizing the coupling parameters. Moreover, we consider a specific system of n harmonic oscillators with bilinear interaction. In this case, decoupling can efficiently be achieved using the combinatorial concept of difference schemes. For this type of interactions we present optimal schemes for inversion.Comment: 19 pages, LaTeX2
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