327 research outputs found

    Using residential segregation to predict colorectal cancer stage at diagnosis: two different approaches

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    Studies have found a variety of evidence regarding the association between residential segregation measures and health outcomes in the US. Some have focused on any individuals living in residentially segregated places, while others have examined whether persons of specific races or ethnicities living in places with high segregation of their own race or ethnicity have differential outcomes. This paper compares and contrasts these two approaches in the study of predictors of late-stage CRC diagnoses in a cross-national study. We argue that it is very important when interpreting results from studies like this to carefully consider the geographic scope of the analysis, which can significantly change the context and meaning of the results

    Simulations of Oligomeric Intermediates in Prion Diseases

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    We extend our previous stochastic cellular automata based model for areal aggregation of prion proteins on neuronal surfaces. The new anisotropic model allow us to simulate both strong beta-sheet and weaker attachment bonds between proteins. Constraining binding directions allows us to generate aggregate structures with the hexagonal lattice symmetry found in recently observed in vitro experiments. We argue that these constraints on rules may correspond to underlying steric constraints on the aggregation process. We find that monomer dominated growth of the areal aggregate is too slow to account for some observed doubling time-to-incubation time ratios inferred from data, and so consider aggregation dominated by relatively stable but non-infectious oligomeric intermediates. We compare a kinetic theory analysis of oligomeric aggregation to spatially explicit simulations of the process. We find that with suitable rules for misfolding of oligomers, possibly due to water exclusion by the surrounding aggregate, the resulting oligomeric aggregation model maps onto our previous monomer aggregation model. Therefore it can produce some of the same attractive features for the description of prion incubation time data. We propose experiments to test the oligomeric aggregation model.Comment: 8 pages, 10 figures For larger versions of several figures, see http://asaph.ucdavis.edu/~dmobley and click on the prion paper lin

    Modeling Geospatial Patterns of Late-Stage Diagnosis of Breast Cancer in the US

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    In the US, about one-third of new breast cancers (BCs) are diagnosed at a late stage, where morbidity and mortality burdens are higher. Health outcomes research has focused on the contribution of measures of social support, particularly the residential isolation or segregation index, on propensity to utilize mammography and rates of late-stage diagnoses. Although inconsistent, studies have used various approaches and shown that residential segregation may play an important role in cancer morbidities and mortality. Some have focused on any individuals living in residentially segregated places (place-centered), while others have focused on persons of specific races or ethnicities living in places with high segregation of their own race or ethnicity (person-centered). This paper compares and contrasts these two approaches in the study of predictors of late-stage BC diagnoses in a cross-national study. We use 100% of U.S. Cancer Statistics (USCS) Registry data pooled together from 40 states to identify late-stage diagnoses among ~1 million new BC cases diagnosed during 2004–2009. We estimate a multilevel model with person-, county-, and state-level predictors and a random intercept specification to help ensure robust effect estimates. Person-level variables in both models suggest that non-White races or ethnicities have higher odds of late-stage diagnosis, and the odds of late-stage diagnosis decline with age, being highest among the <age 50 group. After controlling statistically for all other factors, we examine place-centered isolation and find for anyone living in an isolated Asian community there is a large beneficial association (suggesting lower odds of late-stage diagnosis) while for anyone living in an isolated White community there is a large detrimental association (suggesting greater odds of late-stage diagnosis). By contrast, living in neighborhoods among others of one’s own race or ethnicity (person-centered isolation) is associated with greater odds of late-stage diagnosis, as this measure is dominated by Whites (the majority). At the state level, living in a state that allows unfettered access to a specialist is associated with a somewhat lower likelihood of being diagnosed at a late stage of BC. Geographic factors help explain the likelihood of late-stage BC diagnosis, which varies considerably across the U.S. as heterogeneous compositional and contextual factors portray very different places and potential for improving information and outcomes. The USCS database is expanding to cover more states and is expected to be a valuable resource for ongoing and future place-based cancer outcomes research

    Toward closure of upwelling radiance in coastal waters

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    We present three methods for deriving water-leaving radiance Lw(λ) and remote-sensing reflectance using a hyperspectral tethered spectral radiometer buoy (HyperTSRB), profiled spectroradiometers, and Hydrolight simulations. Average agreement for 53 comparisons between HyperTSRB and spectroradiometric determinations of Lw(λ) was 26%, 13%, and 17% at blue, green, and red wavelengths, respectively. Comparisons of HyperTSRB (and spectroradiometric) Lw(λ) with Hydrolight simulations yielded percent differences of 17% (18%), 17% (18%), and 13% (20%) for blue, green, and red wavelengths, respectively. The differences can be accounted for by uncertainties in model assumptions and model input data (chlorophyll fluorescence quantum efficiency and the spectral chlorophyll-specific absorption coefficient for the red wavelengths, and scattering corrections for input ac-9 absorption data and volume scattering function measurements for blue wavelengths) as well as radiance measurement inaccuracies [largely differences in the depth of the Lu(λ, z) sensor on the HyperTSRB]. © 2003 Optical Society of America

    Targeted Employee Retention: Performance-Based and Job-Related Differences in Reported Reasons for Staying

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    A content model of 12 retention factors is developed in the context of previous theory and research. Coding of open-ended responses from 24,829 employees in the leisure and hospitality industry lends support to the identified framework and reveals that job satisfaction, extrinsic rewards, constituent attachments, organizational commitment, and organizational prestige were the most frequently mentioned reasons for staying. Advancement opportunities and organizational prestige were more common reasons for staying among high performers and non-hourly workers, and extrinsic rewards was more common among low performers and hourly employees, providing support for ease/desirability of movement and psychological contract rationales. The findings highlight the importance of differentiating human resource management practices when the goal is to retain those employees valued most by the organization

    Impact of phytoplankton community size on a linked global ocean optical and ecosystem model

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    Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Elsevier for personal use, not for redistribution. The definitive version was published in Journal of Marine Systems 89 (2012): 61-75, doi:10.1016/j.jmarsys.2011.08.002.We isolated the effect phytoplankton cell size has on varying remote sensing reflectance spectra (Rrs(λ)) in the presence of optically active constituents by using optical and radiative transfer models linked in an offline diagnostic calculation to a global biogeochemical/ecosystem/circulation model with explicit phytoplankton size classes. Two case studies were carried out, each with several scenarios to isolate the effects of chlorophyll concentration, phytoplankton cell size, and size-varying phytoplankton absorption on Rrs(λ). The goal of the study was to determine the relative contribution of phytoplankton cell size and chlorophyll to overall Rrs(λ) and to understand where a standard band ratio algorithm (OC4) may under/overestimate chlorophyll due to Rrs(λ) being significantly affected by phytoplankton size. Phytoplankton cell size was found to contribute secondarily to Rrs(λ) variability and to amplify or dampen the seasonal cycle in Rrs(λ), driven by chlorophyll. Size and chlorophyll were found to change in phase at low to mid-latitudes, but were anti-correlated or poorly correlated at high latitudes. Phytoplankton size effects increased model calculated Rrs(443) in the subtropical ocean during local spring through early fall months in both hemispheres and decreased Rrs(443) in the Northern Hemisphere high latitude regions during local summer to fall months. This study attempts to tease apart when/where variability about the OC4 relationship may be associated with cell size variability. The OC4 algorithm may underestimate [Chl] when the fraction of microplankton is elevated, which occurs in the model simulations during local spring/summer months at high latitudes in both hemispheres.Funding for this study came from a NASA Earth and Space Science Fellowship and University of Rhode Island Graduate School Oceanography Alumni Fellowship, both awarded to C. Mouw. The CCSM-3 BEC simulations were generated with support from NASA Ocean Biology and Biogeochemistry Program (NNX07AL80G) and the NSF Center for Microbial Oceanography Research and Education (C-MORE, EF-0424599)

    Mentoring promotion/tenure-seeking faculty: principles of good practice within a counselor education program

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    Approaches to mentoring junior faculty in counselor education departments have received minimal attention in the counseling literature. In this article, the authors describe a successful program based on the 10 principles for good mentoring recommended by Sorcinelli (2000). Application of the principles within a combined formal and informal mentoring approach is described, as are the experiences of junior faculty whose careers have been shaped within this system

    DOSCATs: Double standards for protein quantification

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    The two most common techniques for absolute protein quantification are based on either mass spectrometry (MS) or on immunochemical techniques, such as western blotting (WB). Western blotting is most often used for protein identification or relative quantification, but can also be deployed for absolute quantification if appropriate calibration standards are used. MS based techniques offer superior data quality and reproducibility, but WB offers greater sensitivity and accessibility to most researchers. It would be advantageous to apply both techniques for orthogonal quantification, but workflows rarely overlap. We describe DOSCATs (DOuble Standard conCATamers), novel calibration standards based on QconCAT technology, to unite these platforms. DOSCATs combine a series of epitope sequences concatenated with tryptic peptides in a single artificial protein to create internal tryptic peptide standards for MS as well as an intact protein bearing multiple linear epitopes. A DOSCAT protein was designed and constructed to quantify five proteins of the NF-κB pathway. For three target proteins, protein fold change and absolute copy per cell values measured by MS and WB were in excellent agreement. This demonstrates that DOSCATs can be used as multiplexed, dual purpose standards, readily deployed in a single workflow, supporting seamless quantitative transition from MS to WB

    Prototype GaAs X‐ray detector and preamplifier electronics for a deep seabed mineral XRF spectrometer

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    Work towards developing a prototype GaAs based X-ray fluorescence spectrometer focusing on the detector-preamplifier system for in situ characterisation of deep seabed minerals is presented. Such an instrument could be useful for marine geology and provide insight into hydrothermal processes. It would also be beneficial for deep sea mining applications. The GaAs photodiode was electrically characterised at 4 °C (ambient seawater temperature) and 33 °C. A system energy resolution (full width at half maximum) at 5.9 keV of 580 eV at 4°C, limited by the dielectric noise, broadening to 680 eV at 33°C, was recorded. The spectral performance of the system was characterised across the energy range 4.95 keV to 21.17 keV, at 33°C, using high-purity X-ray fluorescence calibration samples excited by a Mo target X-ray tube. The charge output from the system was found to be linear with incident photon energy. The energy resolution was found to broaden from 695 eV at 4.95 keV to 735 eV at 21.17 keV, attributed to the increasing Fano noise with energy. The same X-ray tube was used to fluoresce an unprepared manganese nodule (revealing the presence of Mn, Fe, Ni, Cu, Zn, Pb, Sr, and Mo) and a black smoker hydrothermal vent sample (containing Fe, Co, Ni, Cu, Zn, Pb, and Mo). Such a spectrometer may also find use in future space missions to study the hydrothermal vents that are believed to exist in the oceans of Jupiter's moon Europa

    Counselor Education and Supervision

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    Abstract: Approaches to mentoring junior faculty in counselor education departments have received minimal attention in the counseling literature. In this article, the authors describe a successful program based on the 10 principles for good mentoring recommended b
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