3,693 research outputs found

    Multi-frequency fine resolution imaging radar instrumentation and data acquisition

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    Development of a dual polarized L-band radar imaging system to be used in conjunction with the present dual polarized X-band radar is described. The technique used called for heterodyning the transmitted frequency from X-band to L-band and again heterodyning the received L-band signals back to X-band for amplification, detection, and recording

    Legal and Ethical Issues in Evaluating Abortion Services

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    ABSTRACT When evaluation studies are conducted in a sensitive area, ethical and legal implications are bound to challenge evaluators. All too often, evaluators must deal with competing responsibilities in evaluating these programs or services. This article focuses on several ethical and legal issues that arose during an evaluation of abortion services. We discuss how we developed decision rules and considered trade-offs in dealing with these ethical and legal issues so that rational and objective decisions could be reached. We place this discussion within the context of balancing the utility and propriety evaluation standards with respect to obtaining true informed consent and protecting the privacy and confidentiality of data when evaluating abortion services. The article concludes with recommendations concerning the evaluation of abortion services

    Adolescents and Young Adults with Chronic or End-Stage Kidney Disease

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    Adolescents and young adults face unique and complex physical, psychological, and family challenges. Despite improvements in care for chronic kidney disease (CKD) and end-stage kidney disease (ESKD), long-term mortality for children, adolescents, and young adults with CKD remains substantially higher than their healthy counterparts. In this article, we discuss the complex challenges that adolescent and young adult CKD/ESKD patients face. Adolescents have different CKD etiologies and progress along a course dissimilar to the adult population, but have similar multifarious comorbidities. In the setting of puberty and learning to become self-sufficient, adolescence is a critical time for growth and psychosocial development. Physiological complications of CKD underlie many of the long-term outcomes. CKD-mineral and bone disorder and anemia are particularly challenging given that they are exacerbated by the rapid growth of adolescents. Endocrine imbalances and malnutrition can delay and limit growth. All of these factors, together with family dynamics and socioeconomic status, contribute to the poor long-term outcomes and decreased quality of life (QoL) for these patients and their families. Care for the adolescent CKD/ESKD population is uniquely challenging, but research has identified ways in which we can continue to improve long-term outcomes and QoL for adolescents with CKD/ESKD

    Developing a Research Mentorship Program: The American Society of Pediatric Nephrology's Experience

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    Background: Most pediatric nephrologists work in academia. Mentor-mentee relationships provide support and guidance for successful research career. Mentorship program implementation is valuable in medical fields for providing research opportunities to young faculty. Methods: The American Society of Pediatric Nephrology (ASPN) established a research mentorship program to (a) assist with matching of appropriate mentor-mentee dyads and (b) establish metrics for desirable mentor-mentee outcomes with two independent components: (1) the grants review workshop, a short-term program providing mentor feedback on grant proposals, and (2) the longitudinal program, establishing long-term mentor-mentee relationships. Regular surveys of both mentors and mentees were reviewed to evaluate and refine the program. Results: Twelve mentees and 17 mentors participated in the grant review workshop and 19 mentees were matched to mentors in the longitudinal program. A review of NIH RePORTER data indicated that since 2014, 13 NIH grants have been awarded. Mentees in the longitudinal program reported that the program helped most with identifying an outside mentor, improving grant research content, and with general career development. Mentors perceived themselves to be most helpful in assisting with overall career plans. Email communications were preferred over phone or face-to-face communications. Mentees endorsed strong interest in staying in touch with their mentors and 100% of mentors expressed their willingness to serve in the future. Conclusion: This mentorship program was initiated and supported by a relatively small medical society and has shown early success in cultivating mentoring relationships for a future generation of clinician-scientists

    Phenotype of p53 wild-type epitope-specific T cells in the circulation of patients with head and neck cancer

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    CD8(+) cytotoxic T-cell (CTL) specific for non-mutated, wild type (wt) sequence p53 peptides derived from wt or mutant p53 molecules expressed in head and neck squamous cell carcinomas (HNSCC) have been detected in the circulation of patients with this disease. The frequency and differentiation/maturation phenotypes of these anti-tumor specific CTL can reflect the host's immunologic response. Therefore, we investigated the frequency and phenotypes of wt sequence p53 peptide-specific CTL in patients with HNSCC (n = 33) by flow cytometric analysis using HLA-A*0201 tetrameric peptides (tet) complexed with the wt sequence p53(264-272) or p53(149-157) peptide and co-staining with phenotypic markers. One main finding was that increasing frequencies of tet(+) CD8(+) T cells in patients' circulation correlated with increased frequencies of inactive naive tet(+) cells, while those with effector memory and terminally differentiated phenotypes, which are associated with positive anti-tumor immune responses, decreased. We also found that the frequency of circulating tet(+) CD8(+) T cells negatively correlated with p53 expression in tumor tissues and tumor stage. Our findings support further clinical-based investigations to define the frequencies and phenotypes of wt sequence p53 peptide-specific CD8(+) T cells to predict disease severity, enhance selection of patients for inclusion in vaccination trials and highlight prerequisites to enhance immune susceptibility by activation of inactive naive tet+ T cells and/or enhancing circulating effector T cell activity by checkpoint blockage

    Coast-to-Interior Gradient in Recent Northwest Greenland Precipitation Trends (1952–2012)

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    The spatial and temporal variability of precipitation on the Greenland ice sheet is an essential component of surface mass balance, which has been declining in recent years with rising temperatures. We present an analysis of precipitation trends in northwest (NW) Greenland (1952–2012) using instrumental (coastal meteorological station) and proxy records (snow pits and ice cores) to characterize the precipitation gradient from the coast to the ice sheet interior. Snow-pit-derived precipitation near the coast (1950–2000) has increased (~7% decade−1, p \u3c 0.01) whereas there is no significant change observed in interior snow pits. This trend holds for 1981–2012, where calculated precipitation changes decrease in magnitude with increasing distance from the coast: 13% decade−1 (2.4 mm water equivalent (w.e.) decade−2) at coastal Thule air base (AB), 8.6% decade−1 (4.7 mm w.e. decade−2) at the 2Barrel ice core site 150 km from Thule AB, −5.2% decade−1 (1.7 mm w.e. decade−2) at Camp Century located 205 km from Thule AB, and 4.4% decade−1 (1.0 mm w.e. decade−2) at B26 located 500 km from Thule AB. In general, annually averaged precipitation and annually and seasonally averaged mean air temperatures observed at Thule AB follow trends observed in composite coastal Greenland time series, with both notably indicating winter as the fastest warming season in recent periods (1981–2012). Trends (1961–2012) in seasonal precipitation differ, specifically with NW Greenland summer precipitation increasing (~0.6 mm w.e. decade−2) in contrast with decreasing summer precipitation in the coastal composite time series (3.8 mm w.e. decade−2). Differences in precipitation trends between NW Greenland and coastal composite Greenland underscore the heterogeneity in climate influences affecting precipitation. In particular, recent (1981–2012) changes in NW Greenland annual precipitation are likely a response to a weakening North Atlantic oscillation
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