2,352 research outputs found

    Reinventing College Physics for Biologists: Explicating an epistemological curriculum

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    The University of Maryland Physics Education Research Group (UMd-PERG) carried out a five-year research project to rethink, observe, and reform introductory algebra-based (college) physics. This class is one of the Maryland Physics Department's large service courses, serving primarily life-science majors. After consultation with biologists, we re-focused the class on helping the students learn to think scientifically -- to build coherence, think in terms of mechanism, and to follow the implications of assumptions. We designed the course to tap into students' productive conceptual and epistemological resources, based on a theoretical framework from research on learning. The reformed class retains its traditional structure in terms of time and instructional personnel, but we modified existing best-practices curricular materials, including Peer Instruction, Interactive Lecture Demonstrations, and Tutorials. We provided class-controlled spaces for student collaboration, which allowed us to observe and record students learning directly. We also scanned all written homework and examinations, and we administered pre-post conceptual and epistemological surveys. The reformed class enhanced the strong gains on pre-post conceptual tests produced by the best-practices materials while obtaining unprecedented pre-post gains on epistemological surveys instead of the traditional losses.Comment: 35 pages including a 15 page appendix of supplementary material

    Eucrite Impact Melt NWA 5218 - Evidence for a Large Crater on Vesta

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    Northwest Africa (NWA) 5218 is a 76 g achondrite that is classified as a eucrite [1]. However, an initial classification [2] describes it as a "eucrite shock-melt breccia...(in which) large, partially melted cumulate basalt clasts are set in a shock melt flow...". We explore the petrology of this clast-bearing impact melt rock (Fig. 1), which could be a characteristic lithology at large impact craters on asteroid Vesta [3]. Methods: Optical microscopy, scanning electronmicroscopy, and Raman spectroscopy were used on a thin section (Fig. 1) for petrographic characterization. The impact melt composition was determined by 20 m diameter defocused-beam analyses with a Cameca SX-100 electron microprobe. The data from 97 spots were corrected for mineral density effects [4]. Constituent mineral phases were analyzed with a focusedbeam. Bidirectonal visible and near-infrared (VNIR) and biconical FT-IR reflectance spectra were measured on the surface of a sample slab on its central melt area and on an eucrite clast, and from 125-500 m and 100 m are coarse-grained with equigranular ~1 mm size plagioclase, quartz, and clinopyroxene (Fig. 1). Single crystals of chromite, ilmenite, zircon, Ca-Mg phosphate, Fe-metal, and troilite are embedded in the melt. Polymineralic clasts are mostly compositionally similar to the above mentioned larger clasts but scarce granulitic fragments are observed as well

    Changes in Sexual Roles and Quality of Life for Gay Men after Prostate Cancer: Challenges for Sexual Health Providers

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    Introduction Gay men with prostate cancer ( GMPCa ) may have differential health‐related quality of life ( HRQOL ) and sexual health outcomes than heterosexual men with prostate cancer ( PCa ), but existing information is based on clinical experience and small studies. Aims Our goals were to: (i) describe HRQOL and examine changes in sexual functioning and bother; (ii) explore the psychosocial aspects of sexual health after PCa ; and (iii) examine whether there were significant differences on HRQOL and sexual behavior between GMPCa and published norms. Methods A convenience sample of GMPCa completed validated disease‐specific and general measures of HRQOL , ejaculatory function and bother, fear of cancer recurrence, and satisfaction with prostate cancer care. Measures of self‐efficacy for PCa management, illness intrusiveness, and disclosure of sexual orientation were also completed. Where possible, scores were compared against published norms. Main Outcome Measures Main outcome measures were self‐reported sexual functioning and bother on the E xpanded P rostate C ancer I ndex. Results Compared with norms, GMPCa reported significantly worse functioning and more severe bother scores on urinary, bowel, hormonal symptom scales ( P s < 0.015–0.0001), worse mental health functioning ( P  < 0.0001), greater fear of cancer recurrence ( P  < 0.0001), and were more dissatisfied with their PCa medical care. However, GMPCa reported better sexual functioning scores ( P  < 0.002) compared with norms. Many of the observed differences met criteria for clinical significance. Physical functioning HRQOL and sexual bother scores were similar to that of published samples. GMPCa tended to be more “out” about their sexual orientation than other samples of gay men. Conclusions GMPCa reported substantial changes in sexual functioning after PCa treatment. They also reported significantly worse disease‐specific and general HRQOL , fear of recurrence, and were less satisfied with their medical care than other published PCa samples. Sexual health providers must have an awareness of the unique functional and HRQOL differences between gay and heterosexual men with PCa. Hart TL, Coon DW, Kowalkowski MA, Zhang K, Hersom JI, Goltz HH, Wittmann DA, and Latini DM. Changes in sexual roles and quality of life for gay men after prostate cancer: Challenges for sexual health providers. J Sex Med 2014;11:2308–2317.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108360/1/jsm12598.pd

    Negative information seeking experiences of long-term prostate cancer survivors

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    Purpose Many prostate cancer survivors have lasting symptoms and disease-related concerns for which they seek information. To understand survivors’ information seeking experiences, we examined the topics of their information searches, their overall perceptions of the search, and perceptions of their health information seeking self-efficacy (i.e., confidence in their ability to obtain information). We hypothesized that negative search experiences and lower health information seeking self-efficacy would be associated with certain survivor characteristics such as non-white race, low income, and less education. Methods This was a retrospective study using data from the Michigan Prostate Cancer Survivor Study (state-based survey of long-term prostate cancer survivor outcomes, N=2,499, response rate = 38%). Participants recalled their last search for information and reported the topics and overall experience. We conducted multivariable regression to examine the association between survivor characteristics and the information-seeking experience. Results Nearly a third (31.7%) of prostate cancer survivors (median age of 76 years and 9 years since diagnosis) reported having negative information seeking experiences when looking for information. However, only 13.4% reported having low health information seeking self-efficacy. Lower income and less education were both significantly associated with negative information seeking experiences. Conclusions Our findings suggest that many long-term prostate cancer survivors have negative experiences when searching for information, and lower income and less education were survivor factors related to negative information seeking experiences. Implications for cancer survivors We advocate for ongoing, information needs assessment at the point-of-care as the survivorship experience progresses to assess and potentially improve survivors’ quality of life

    Forecasting the Impacts of Silver and Bighead Carp on the Lake Erie Food Web

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    Nonindigenous bigheaded carps (Bighead Carp Hypophthalmichthys nobilis and Silver Carp H. molitrix; hereafter, “Asian carps” [AC]) threaten to invade and disrupt food webs and fisheries in the Laurentian Great Lakes through their high consumption of plankton. To quantify the potential effects of AC on the food web in Lake Erie, we developed an Ecopath with Ecosim (EwE) food web model and simulated four AC diet composition scenarios (high, low, and no detritus and low detritus with Walleye Sander vitreus and Yellow Perch Perca flavescens larvae) and two nutrient load scenarios (the 1999 baseline load and 2× the baseline [HP]). We quantified the uncertainty of the potential AC effects by coupling the EwE model with estimates of parameter uncertainty in AC production, consumption, and predator diets obtained using structured expert judgment. Our model projected mean ± SD AC equilibrium biomass ranging from 52 ± 34 to 104 ± 75 kg/ha under the different scenarios. Relative to baseline simulations without AC, AC invasion under all detrital diet scenarios decreased the biomass of most fish and zooplankton groups. The effects of AC in the HP scenario were similar to those in the detrital diet scenarios except that the biomasses of most Walleye and Yellow Perch groups were greater under HP because these fishes were buffered from competition with AC by increased productivity at lower trophic levels. Asian carp predation on Walleye and Yellow Perch larvae caused biomass declines among all Walleye and Yellow Perch groups. Large food web impacts of AC occurred in only 2% of the simulations, where AC biomass exceeded 200 kg/ha, resulting in biomass declines of zooplankton and planktivorous fish near the levels observed in the Illinois River. Our findings suggest that AC would affect Lake Erie's food web by competing with other planktivorous fishes and by providing additional prey for piscivores. Our methods provide a novel approach for including uncertainty into forecasts of invasive species' impacts on aquatic food webs. Received December 6, 2014; accepted July 15, 201

    Molecularly defined diffuse leptomeningeal glioneuronal tumor (DLGNT) comprises two subgroups with distinct clinical and genetic features

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    Diffuse leptomeningeal glioneuronal tumors (DLGNT) represent rare CNS neoplasms which have been included in the 2016 update of the WHO classification. The wide spectrum of histopathological and radiological features can make this enigmatic tumor entity difficult to diagnose. In recent years, large-scale genomic and epigenomic analyses have afforded insight into key genetic alterations occurring in multiple types of brain tumors and provide unbiased, complementary tools to improve diagnostic accuracy. Through genome-wide DNA methylation screening of &gt; 25,000 tumors, we discovered a molecularly distinct class comprising 30 tumors, mostly diagnosed histologically as DLGNTs. Copy-number profiles derived from the methylation arrays revealed unifying characteristics, including loss of chromosomal arm 1p in all cases. Furthermore, this molecular DLGNT class can be subdivided into two subgroups [DLGNT methylation class (MC)-1 and DLGNT methylation class (MC)-2], with all DLGNT-MC-2 additionally displaying a gain of chromosomal arm 1q. Co-deletion of 1p/19q, commonly seen in IDH-mutant oligodendroglioma, was frequently observed in DLGNT, especially in DLGNT-MC-1 cases. Both subgroups also had recurrent genetic alterations leading to an aberrant MAPK/ERK pathway, with KIAA1549:BRAF fusion being the most frequent event. Other alterations included fusions of NTRK1/2/3 and TRIM33:RAF1, adding up to an MAPK/ERK pathway activation identified in 80% of cases. In the DLGNT-MC-1 group, age at diagnosis was significantly lower (median 5 vs 14 years, p &lt; 0.01) and clinical course less aggressive (5-year OS 100, vs 43% in DLGNT-MC-2). Our study proposes an additional molecular layer to the current histopathological classification of DLGNT, of particular use for cases without typical morphological or radiological characteristics, such as diffuse growth and radiologic leptomeningeal dissemination. Recurrent 1p deletion and MAPK/ERK pathway activation represent diagnostic biomarkers and therapeutic targets, respectively—laying the foundation for future clinical trials with, e.g., MEK inhibitors that may improve the clinical outcome of patients with DLGNT

    Forecasting the Impacts of Silver and Bighead Carp on the Lake Erie Food Web

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    Nonindigenous bigheaded carps (Bighead Carp Hypophthalmichthys nobilis and Silver Carp H. molitrix; hereafter, “Asian carps” [AC]) threaten to invade and disrupt food webs and fisheries in the Laurentian Great Lakes through their high consumption of plankton. To quantify the potential effects of AC on the food web in Lake Erie, we developed an Ecopath with Ecosim (EwE) food web model and simulated four AC diet composition scenarios (high, low, and no detritus and low detritus with Walleye Sander vitreus and Yellow Perch Perca flavescens larvae) and two nutrient load scenarios (the 1999 baseline load and 2× the baseline [HP]). We quantified the uncertainty of the potential AC effects by coupling the EwE model with estimates of parameter uncertainty in AC production, consumption, and predator diets obtained using structured expert judgment. Our model projected mean ± SD AC equilibrium biomass ranging from 52 ± 34 to 104 ± 75 kg/ha under the different scenarios. Relative to baseline simulations without AC, AC invasion under all detrital diet scenarios decreased the biomass of most fish and zooplankton groups. The effects of AC in the HP scenario were similar to those in the detrital diet scenarios except that the biomasses of most Walleye and Yellow Perch groups were greater under HP because these fishes were buffered from competition with AC by increased productivity at lower trophic levels. Asian carp predation on Walleye and Yellow Perch larvae caused biomass declines among all Walleye and Yellow Perch groups. Large food web impacts of AC occurred in only 2% of the simulations, where AC biomass exceeded 200 kg/ha, resulting in biomass declines of zooplankton and planktivorous fish near the levels observed in the Illinois River. Our findings suggest that AC would affect Lake Erie's food web by competing with other planktivorous fishes and by providing additional prey for piscivores. Our methods provide a novel approach for including uncertainty into forecasts of invasive species' impacts on aquatic food webs. Received December 6, 2014; accepted July 15, 201

    Distortions of Subjective Time Perception Within and Across Senses

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    Background: The ability to estimate the passage of time is of fundamental importance for perceptual and cognitive processes. One experience of time is the perception of duration, which is not isomorphic to physical duration and can be distorted by a number of factors. Yet, the critical features generating these perceptual shifts in subjective duration are not understood. Methodology/Findings: We used prospective duration judgments within and across sensory modalities to examine the effect of stimulus predictability and feature change on the perception of duration. First, we found robust distortions of perceived duration in auditory, visual and auditory-visual presentations despite the predictability of the feature changes in the stimuli. For example, a looming disc embedded in a series of steady discs led to time dilation, whereas a steady disc embedded in a series of looming discs led to time compression. Second, we addressed whether visual (auditory) inputs could alter the perception of duration of auditory (visual) inputs. When participants were presented with incongruent audio-visual stimuli, the perceived duration of auditory events could be shortened or lengthened by the presence of conflicting visual information; however, the perceived duration of visual events was seldom distorted by the presence of auditory information and was never perceived shorter than their actual durations. Conclusions/Significance: These results support the existence of multisensory interactions in the perception of duration and, importantly, suggest that vision can modify auditory temporal perception in a pure timing task. Insofar as distortions in subjective duration can neither be accounted for by the unpredictability of an auditory, visual or auditory-visual event, we propose that it is the intrinsic features of the stimulus that critically affect subjective time distortions
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