727 research outputs found
Temperature-sensitive Tien Shan tree ring chronologies show multi-centennial growth trends
Two millennia-length juniper ring width chronologies, processed to preserve multi-centennial growth trends, are presented for the Alai Range of the western Tien Shan in Kirghizia. The chronologies average the information from seven near-timberline sampling sites, and likely reflect summer temperature variation. For comparison, chronologies are also built using standard dendrochronological techniques. We briefly discuss some qualities of these "inter-decadal” records, and show the low frequency components removed by the standardization process include a long-term negative trend in the first half of the last millennium and a long-term positive trend since about AD 1800. The multi-centennial scale Alai Range chronologies, where these trends are retained, are both systematically biased (but in an opposite sense) in their low frequency domains. Nevertheless, they represent the best constraints and estimates of long-term summer temperature variation, and reflect the Medieval Warm Period, the Little Ice Age, and a period of warming since about the middle of the nineteenth centur
Linear Estimation of Location and Scale Parameters Using Partial Maxima
Consider an i.i.d. sample X^*_1,X^*_2,...,X^*_n from a location-scale family,
and assume that the only available observations consist of the partial maxima
(or minima)sequence, X^*_{1:1},X^*_{2:2},...,X^*_{n:n}, where
X^*_{j:j}=max{X^*_1,...,X^*_j}. This kind of truncation appears in several
circumstances, including best performances in athletics events. In the case of
partial maxima, the form of the BLUEs (best linear unbiased estimators) is
quite similar to the form of the well-known Lloyd's (1952, Least-squares
estimation of location and scale parameters using order statistics, Biometrika,
vol. 39, pp. 88-95) BLUEs, based on (the sufficient sample of) order
statistics, but, in contrast to the classical case, their consistency is no
longer obvious. The present paper is mainly concerned with the scale parameter,
showing that the variance of the partial maxima BLUE is at most of order
O(1/log n), for a wide class of distributions.Comment: This article is devoted to the memory of my six-years-old, little
daughter, Dionyssia, who leaved us on August 25, 2010, at Cephalonia isl. (26
pages, to appear in Metrika
The version available in this research repository is a preprint. Its content does not reflect the peer-review process and it lacks publisher layout and branding
Immigration represents a promising counter-narrative for Rust Belt cities in the 21st century. Increasingly, both immigrants and refugees are part of the comeback stories of Northeastern and Midwestern cities from Buffalo, to Dayton and Pittsburgh. This review explores recent research in urban geography and allied disciplines focusing on the international migration patterns,
processes, and politics reshaping the urban geography of the American Rust Belt. Recent research sheds crucial light on how im/migrant lives are reshaping urban landscapes of Rust Belt cities, and conversely, how local immigration policies in these cities are rearranging the uneven geographies of immigrant receptivity across the U.S. Overall, this review highlights the limitations of the singular spatial imaginary of the Rust Belt advanced previously by many urbanists. Rather, this review illustrates the rich, complex, and tangled contemporary spatial nuances associated with international migration in this region. These spatial nuances are complicated by increasingly exclusionary immigration policy and rhetoric at the federal level since January of 2017
Observations of Collective Ion Acceleration by a Relativistic Electron Beam in a Magnetic Cusp
Leadership Training in Endocrinology Fellowship? A Survey of Program Directors and Recent Graduates
Context: There is growing recognition that more physician leaders are needed to navigate the next era of medicine.
Objective: To determine current opinions about leadership training in endocrinology fellowship programs.
Design/Participants: Twenty-seven-question survey addressing various aspects of leadership training to current nationwide fellowship program directors (PDs) and fellowship graduates since 2010.
Intervention: In partnership with the Endocrine Society, the electronic survey was advertised primarily via direct e-mail. It was open from March through July 2016.
Main Outcome Measures: The survey addressed leadership traits, importance of leadership training, preferred timing, and content of leadership training.
Results: Forty-six of 138 PDs (33.3%) and 147 of 1769 graduates (8.3%) completed the survey. Among PDs and graduates, there was strong agreement (\u3e95%) about important leadership characteristics, including job knowledge, character traits, team-builder focus, and professional skills. PDs (64.5%) and graduates (60.8%) favored teaching leadership skills during fellowship, with PDs favoring mentoring/coaching (75.0%), direct observation of staff clinicians (72.5%), and seminars (72.5%). Graduates favored a variety of approaches. Regarding topics to include in a leadership curriculum, PDs responded that communication skills (97.5%), team building (95.0%), professional skills (90.0%), clinic management (87.5%), strategies to impact the delivery of endocrinology care (85.0%), and personality skills (82.5%) were most important. Graduates responded similarly, with \u3e80% agreement for each topic. Finally, most PDs (89%) expressed a desire to incorporate more leadership training into their programs.
Conclusions: Our survey suggests a need for leadership training in endocrinology fellowships. More work is needed to determine how best to meet this need
Improving statistical inference on pathogen densities estimated by quantitative molecular methods: malaria gametocytaemia as a case study
BACKGROUND: Quantitative molecular methods (QMMs) such as quantitative real-time polymerase chain reaction (q-PCR), reverse-transcriptase PCR (qRT-PCR) and quantitative nucleic acid sequence-based amplification (QT-NASBA) are increasingly used to estimate pathogen density in a variety of clinical and epidemiological contexts. These methods are often classified as semi-quantitative, yet estimates of reliability or sensitivity are seldom reported. Here, a statistical framework is developed for assessing the reliability (uncertainty) of pathogen densities estimated using QMMs and the associated diagnostic sensitivity. The method is illustrated with quantification of Plasmodium falciparum gametocytaemia by QT-NASBA. RESULTS: The reliability of pathogen (e.g. gametocyte) densities, and the accompanying diagnostic sensitivity, estimated by two contrasting statistical calibration techniques, are compared; a traditional method and a mixed model Bayesian approach. The latter accounts for statistical dependence of QMM assays run under identical laboratory protocols and permits structural modelling of experimental measurements, allowing precision to vary with pathogen density. Traditional calibration cannot account for inter-assay variability arising from imperfect QMMs and generates estimates of pathogen density that have poor reliability, are variable among assays and inaccurately reflect diagnostic sensitivity. The Bayesian mixed model approach assimilates information from replica QMM assays, improving reliability and inter-assay homogeneity, providing an accurate appraisal of quantitative and diagnostic performance. CONCLUSIONS: Bayesian mixed model statistical calibration supersedes traditional techniques in the context of QMM-derived estimates of pathogen density, offering the potential to improve substantially the depth and quality of clinical and epidemiological inference for a wide variety of pathogens
Defining Responses to Therapy and Study Outcomes in Clinical Trials of Invasive Fungal Diseases: Mycoses Study Group and European Organization for Research and Treatment of Cancer Consensus Criteria
Invasive fungal diseases (IFDs) have become major causes of morbidity and mortality among highly immunocompromised patients. Authoritative consensus criteria to diagnose IFD have been useful in establishing eligibility criteria for antifungal trials. There is an important need for generation of consensus definitions of outcomes of IFD that will form a standard for evaluating treatment success and failure in clinical trials. Therefore, an expert international panel consisting of the Mycoses Study Group and the European Organization for Research and Treatment of Cancer was convened to propose guidelines for assessing treatment responses in clinical trials of IFDs and for defining study outcomes. Major fungal diseases that are discussed include invasive disease due to Candida species, Aspergillus species and other molds, Cryptococcus neoformans, Histoplasma capsulatum, and Coccidioides immitis. We also discuss potential pitfalls in assessing outcome, such as conflicting clinical, radiological, and/or mycological data and gaps in knowledg
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