234 research outputs found

    Reading Matters : A Case Study of a Community Volunteer Tutoring Program

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    The objective of this qualitative research was to study through a phenomenological approach Reading Matters, a community volunteer reading program to determine if students are demonstrating improvement, to uncover the characteristics of the program and the tutoring techniques used by volunteers, and to create a potential model by which administrators can design volunteer tutoring programs for other schools. One coordinator, one principal, eight classroom teachers, three volunteers, and five students participated in the study. Conclusions drawn indicate that the volunteer tutoring program was successful for the students not only for academic results but also for the mentoring relationship that the tutoring sessions created

    HIghMass - High HI Mass, HI-Rich Galaxies at z∼0z\sim0: Combined HI and H2_2 Observations

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    We present resolved HI and CO observations of three galaxies from the HIghMass sample, a sample of HI-massive (MHI>1010M⊙M_{HI} > 10^{10} M_\odot), gas-rich (MHIM_{HI} in top 5%5\% for their M∗M_*) galaxies identified in the ALFALFA survey. Despite their high gas fractions, these are not low surface brightness galaxies, and have typical specific star formation rates (SFR/M∗/M_*) for their stellar masses. The three galaxies have normal star formation rates for their HI masses, but unusually short star formation efficiency scale lengths, indicating that the star formation bottleneck in these galaxies is in the conversion of HI to H2_2, not in converting H2_2 to stars. In addition, their dark matter spin parameters (λ\lambda) are above average, but not exceptionally high, suggesting that their star formation has been suppressed over cosmic time but are now becoming active, in agreement with prior Hα\alpha observations.Comment: 20 pages, 13 figure

    Testing the early Late Ordovician cool-water hypothesis with oxygen isotopes from conodont apatite

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    © 2017 Cambridge University Press. Latest Sandbian to early Katian sequences across Laurentia\u27s epicontinental sea exhibit a transition from lithologies characterized as \u27warm-water\u27 carbonates to those characterized as \u27cool-water\u27carbonates. This shift occurs across the regionally recognized M4/M5 sequence stratigraphic boundary and has been attributed to climatic cooling and glaciation, basin reorganization and upwelling of open ocean water, and/or increased water turbidity and terrigenous input associated with the Taconic tectophase. Documentation of oxygen isotopic trends across the M4/M5 and through bracketing strata provides a potential means of distinguishing among these alternative scenarios; however, oxygen isotopic records generated to date have failed to settle the debate. This lack of resolution is because δ18O records are open to multiple interpretations and potentially confounding factors related to local environmental conditions have not been tested by examining the critical interval in multiple areas and different depositional settings. To begin to address this shortcoming, we present new species-specific and mixed assemblage conodont δ18O values in samples spanning the M4/M5 boundary from the Upper Mississippi Valley, Alabama, and Virginia. The new results are combined with previous studies, providing a record of δ18O variability across SE Laurentia. The combined dataset allows us to test for regional trends at a resolution not previously available. Our results document a ~1.5‰ decrease in values across Laurentia instead of increasing δ18O values across the M4/M5 as predicted in various \u27cool-water\u27 scenarios. In short, these results do not support a shift to \u27cool-water\u27 conditions as an explanation for changes in early Katian carbonates across the M4/M5

    Filtering Medline for a clinical discipline: diagnostic test assessment framework

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    Objective To develop and test a Medline filter that allows clinicians to search for articles within a clinical discipline, rather than searching the entire Medline database

    Shorter Survival of SDF1-3′A/3′A Homozygotes Linked to CD4+ T Cell Decrease in Advanced Human Immunodeficiency Virus Type 1 Infection

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    The SDF-1 3′A allelic polymorphism has been reported to influence either positively or negatively the progression of human immunodeficiency virus type 1 (HIV-1) disease. Therefore, the SDF-1 genotype of 729 HIV-1-infected individuals pooled from 3 distinct cohorts was determined. A statistically nonsignificant association between the SDF1-3′A/3′A genotype and accelerated disease progression was evident among seroconverters (n = 319), but a striking correlation of decreased survival after either diagnosis of AIDS according to the 1993 definition or loss of CD4+ T cell counts <200 was observed. The relative hazards for SDF1-3′A/3′A homozygotes, compared with heterozygotes and wild-type homozygotes were 2.16 (P = .0047), for time from diagnosis according to the 1993 Centers for Disease Control and Prevention AIDS case definition (AIDS-'93) to death, and 3.43 (P = .0001), for time from CD4+ T cells <200 to death. Because no difference in survival was observed after diagnosis according to AIDS-'87, the association of the SDF1-3′A/3′A genotype with the accelerated progression of late-stage HIV-1 disease appears to be explained for the most part by the loss of CD4+ T lymphocyte

    HIghMass—High H I Mass, H I-rich Galaxies at z ~ 0: Combined H I and H_2 Observations

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    We present resolved and CO observations of three galaxies from the HIghMass sample, a sample of -massive (M_(H I) > 10^(10) M⊙), gas-rich (M_(H I) in the top 5% for their M *) galaxies identified in the ALFALFA survey. Despite their high gas fractions, these are not low-surface-brightness galaxies and have typical specific star formation rates (SFR/M*) for their stellar masses. The three galaxies have normal SFRs for their masses, but unusually short star formation efficiency scale lengths, indicating that the star formation bottleneck in these galaxies is in the conversion of H I to H_2, not in converting H_2 to stars. In addition, their dark matter spin parameters (λ) are above average, but not exceptionally high, suggesting that their star formation has been suppressed over cosmic time but is now becoming active, in agreement with prior Hα observations

    Prophylactic evaluation of verubecestat on disease- and symptom-modifying effects in 5XFAD mice.

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    Introduction: Alzheimer\u27s disease (AD) is the most common form of dementia. Beta-secretase (BACE) inhibitors have been proposed as potential therapeutic interventions; however, initiating treatment once disease has significantly progressed has failed to effectively stop or treat disease. Whether BACE inhibition may have efficacy when administered prophylactically in the early stages of AD has been under-investigated. The present studies aimed to evaluate prophylactic treatment of the BACE inhibitor verubecestat in an AD mouse model using the National Institute on Aging (NIA) resources of the Model Organism Development for Late-Onset Alzheimer\u27s Disease (MODEL-AD) Preclinical Testing Core (PTC) Drug Screening Pipeline. Methods: 5XFAD mice were administered verubecestat ad libitum in chow from 3 to 6 months of age, prior to the onset of significant disease pathology. Following treatment (6 months of age), in vivo imaging was conducted with 18F-florbetapir (AV-45/Amyvid) (18F-AV45) and 18-FDG (fluorodeoxyglucose)-PET (positron emission tomography)/MRI (magnetic resonance imaging), brain and plasma amyloid beta (Aβ) were measured, and the clinical and behavioral characteristics of the mice were assessed and correlated with the pharmacokinetic data. Results: Prophylactic verubecestat treatment resulted in dose- and region-dependent attenuations of 18F-AV45 uptake in male and female 5XFAD mice. Plasma Aβ40 and Aβ42 were also dose-dependently attenuated with treatment. Across the dose range evaluated, side effects including coat color changes and motor alterations were reported, in the absence of cognitive improvement or changes in 18F-FDG uptake. Discussion: Prophylactic treatment with verubecestat resulted in attenuated amyloid plaque deposition when treatment was initiated prior to significant pathology in 5XFAD mice. At the same dose range effective at attenuating Aβ levels, verubecestat produced side effects in the absence of improvements in cognitive function. Taken together these data demonstrate the rigorous translational approaches of the MODEL-AD PTC for interrogating potential therapeutics and provide insight into the limitations of verubecestat as a prophylactic intervention for early-stage AD

    Testing Simulation Theory with Cross-Modal Multivariate Classification of fMRI Data

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    The discovery of mirror neurons has suggested a potential neural basis for simulation and common coding theories of action perception, theories which propose that we understand other people's actions because perceiving their actions activates some of our neurons in much the same way as when we perform the actions. We propose testing this model directly in humans with functional magnetic resonance imaging (fMRI) by means of cross-modal classification. Cross-modal classification evaluates whether a classifier that has learned to separate stimuli in the sensory domain can also separate the stimuli in the motor domain. Successful classification provides support for simulation theories because it means that the fMRI signal, and presumably brain activity, is similar when perceiving and performing actions. In this paper we demonstrate the feasibility of the technique by showing that classifiers which have learned to discriminate whether a participant heard a hand or a mouth action, based on the activity patterns in the premotor cortex, can also determine, without additional training, whether the participant executed a hand or mouth action. This provides direct evidence that, while perceiving others' actions, (1) the pattern of activity in premotor voxels with sensory properties is a significant source of information regarding the nature of these actions, and (2) that this information shares a common code with motor execution
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