4,415 research outputs found

    Fostering Transformative Learning, Self-reflexivity and Medical Citizenship Through Guided Tours of Disadvantaged Neighborhoods

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    Background and objectives: Medical school curricula increasingly seek to promote medical students’ commitment to redressing health disparities, but traditional pedagogical approaches have fallen short of this goal. The objective of this work was to assess the value of using community-based guided tours of disadvantaged neighborhoods to fill this gap. Methods: A total of 50 second-year medical students participated in a guided tour of disadvantaged public housing neighborhoods in Richmond, Virginia. Students completed self-reflexive writing exercises during a post-tour debriefing session. Student writings were analyzed to assess the tour’s effect on their awareness of poverty’s impact on vulnerable populations’ health and wellbeing, and their personal reactions to the tour. Results: Student writings indicated that the activity fostered transformative learning experiences around the issue of poverty and its effects on health and stimulated a personal commitment to working with underserved populations. Themes from qualitative analysis included: increased awareness of the extent of poverty, enhanced self-reflexive attitude towards personal feelings, biases and misperceptions concerning the poor, increased intentional awareness of the effects of poverty on patient health and well-being, and, encouragement to pursue careers of medical service. Conclusions: This pilot demonstrated that incorporating self-reflexive learning exercises into a brief community-based guided tour can enhance the social consciousness of medical students by deepening understandings of health disparities and promoting transformative learning experiences

    Scaling of Splay and Total Rigidity for Elastic Percolation on the Triangular Lattice

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    The randomly diluted elastic network with central force interactions is simulated on the triangular lattice using a constraint analysis of cluster displacement vectors. The exponents for the percolation of splay and total rigidity are found to be the same, ν=1.14±0.1, γ=1.6±0.3, and β=0.46±0.4. The concentration of bonds that are in clusters rigid only with respect to a splay deformation is evaluated as a function of bond concentration. The area under the resulting distribution diminishes with lattice size as ∼L−1.1, indicating that splay and total rigidity have the same threshold, pc≊0.64

    A “Behind-the-Scenes” Look at Interprofessional Care Coordination: How Person-Centered Care in Safety-Net Health System Complex Care Clinics Produce Better Outcomes

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    Introduction: While the effectiveness of team-based care and wrap-around services for high utilizers is clear, how complex care clinics deliver effective, person-centered care to these vulnerable populations is not well understood. This paper describes how interactions among interprofessional team members enabled individualized, rapid responses to the complex needs of vulnerable patients at the Virginia Commonwealth University Health System’s Complex Care Clinic. Methods: Researchers attended twenty weekly care coordination meetings, audio-recorded the proceedings, and wrote brief observational field notes. Researchers also qualitatively interviewed ten clinic team members. Emergent coding based on grounded theory and a consensus process were used to identify and describe key themes. Results: Analysis resulted in three themes that evidence the structures, processes, and interactions which contributed to the ability to provide person-centred care: team-based communication strategies, interprofessional problem-solving, and personalized patient engagement efforts. Conclusion: Our study suggests that in care coordination meetings team members were able to strategize, brainstorm, and reflect on how to better care for patients. Specifically, flexible team leadership opened an inter-disciplinary communicative space to foster conversations, which revealed connections between the physical, and socio-emotional components of patients’ lives and hidden factors undermining progress, while proactive strategies prevented patient’s rapid deterioration and unnecessary use of inappropriate health services

    COX-1 and COX-2 in Human Periodontal Disease States

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    Cyclooxygenase (COX) catalyses the conversion of arachidonic acid into prostanoids and related compounds which have been implicated in periodontal bone loss. Therefore, the aim of this study was to quantify COX-1 and COX-2 expression in gingival tissue derived from healthy/gingivitis and periodontitis sites

    Quasar accretion disk sizes from continuum reverberation mapping in the DES standard-star fields

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    Measurements of the physical properties of accretion disks in active galactic nuclei are important for better understanding the growth and evolution of supermassive black holes. We present the accretion disk sizes of 22 quasars from continuum reverberation mapping with data from the Dark Energy Survey (DES) standard star fields and the supernova C fields. We construct continuum lightcurves with the \textit{griz} photometry that span five seasons of DES observations. These data sample the time variability of the quasars with a cadence as short as one day, which corresponds to a rest frame cadence that is a factor of a few higher than most previous work. We derive time lags between bands with both JAVELIN and the interpolated cross-correlation function method, and fit for accretion disk sizes using the JAVELIN Thin Disk model. These new measurements include disks around black holes with masses as small as 107\sim10^7 MM_{\odot}, which have equivalent sizes at 2500\AA \, as small as 0.1\sim 0.1 light days in the rest frame. We find that most objects have accretion disk sizes consistent with the prediction of the standard thin disk model when we take disk variability into account. We have also simulated the expected yield of accretion disk measurements under various observational scenarios for the Large Synoptic Survey Telescope Deep Drilling Fields. We find that the number of disk measurements would increase significantly if the default cadence is changed from three days to two days or one day.Comment: 33 pages, 24 figure

    Astrometric calibration and performance of the Dark Energy Camera

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    We characterize the ability of the Dark Energy Camera (DECam) to perform relative astrometry across its 500~Mpix, 3 deg^2 science field of view, and across 4 years of operation. This is done using internal comparisons of ~4x10^7 measurements of high-S/N stellar images obtained in repeat visits to fields of moderate stellar density, with the telescope dithered to move the sources around the array. An empirical astrometric model includes terms for: optical distortions; stray electric fields in the CCD detectors; chromatic terms in the instrumental and atmospheric optics; shifts in CCD relative positions of up to ~10 um when the DECam temperature cycles; and low-order distortions to each exposure from changes in atmospheric refraction and telescope alignment. Errors in this astrometric model are dominated by stochastic variations with typical amplitudes of 10-30 mas (in a 30 s exposure) and 5-10 arcmin coherence length, plausibly attributed to Kolmogorov-spectrum atmospheric turbulence. The size of these atmospheric distortions is not closely related to the seeing. Given an astrometric reference catalog at density ~0.7 arcmin^{-2}, e.g. from Gaia, the typical atmospheric distortions can be interpolated to 7 mas RMS accuracy (for 30 s exposures) with 1 arcmin coherence length for residual errors. Remaining detectable error contributors are 2-4 mas RMS from unmodelled stray electric fields in the devices, and another 2-4 mas RMS from focal plane shifts between camera thermal cycles. Thus the astrometric solution for a single DECam exposure is accurate to 3-6 mas (0.02 pixels, or 300 nm) on the focal plane, plus the stochastic atmospheric distortion.Comment: Submitted to PAS

    Mir142 loss unlocks IDH2R140-dependent leukemogenesis through antagonistic regulation of HOX genes

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    AML is a genetically heterogeneous disease and understanding how different co-occurring mutations cooperate to drive leukemogenesis will be crucial for improving diagnostic and therapeutic options for patients. MIR142 mutations have been recurrently detected in IDH-mutated AML samples. Here, we have used a mouse model to investigate the interaction between these two mutations and demonstrate a striking synergy between Mir142 loss-of-function and IDH2R140Q, with only recipients of double mutant cells succumbing to leukemia. Transcriptomic analysis of the non-leukemic single and leukemic double mutant progenitors, isolated from these mice, suggested a novel mechanism of cooperation whereby Mir142 loss-of-function counteracts aberrant silencing of Hoxa cluster genes by IDH2R140Q. Our analysis suggests that IDH2R140Q is an incoherent oncogene, with both positive and negative impacts on leukemogenesis, which requires the action of cooperating mutations to alleviate repression of Hoxa genes in order to advance to leukemia. This model, therefore, provides a compelling rationale for understanding how different mutations cooperate to drive leukemogenesis and the context-dependent effects of oncogenic mutations
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