389 research outputs found

    Recursive estimation of possibly misspecified MA(1) models: Convergence of a general algorithm

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    We introduce a recursive algorithm of conveniently general form for estimating the coefficient of a moving average model of order one and obtain convergence results for both correct and misspecified MA(1) models. The algorithm encompasses Pseudolinear Regression (PLR--also referred to as AML and RML1RML_1) and Recursive Maximum Likelihood (RML2RML_2) without monitoring. Stimulated by the approach of Hannan (1980), our convergence results are obtained indirectly by showing that the recursive sequence can be approximated by a sequence satisfying a recursion of simpler (Robbins-Monro) form for which convergence results applicable to our situation have recently been obtained.Comment: Published at http://dx.doi.org/10.1214/074921706000000932 in the IMS Lecture Notes Monograph Series (http://www.imstat.org/publications/lecnotes.htm) by the Institute of Mathematical Statistics (http://www.imstat.org

    Influence of Calibration Factors on Crash Prediction on Rural Two-Lane, Two-Way Roadway Segments

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    [EN] Calibration factors are applied in the Highway Safety Manual predictive method for rural two-lane, two-way roadway segments to adjust the estimate for local conditions. This research aims to evaluate and recommend improvements related to the estimation of these calibration factors. An aggregated and disaggregated analysis was performed to study the influence of different calibration factors on the prediction of the number of crashes in North Carolina. As a result, those calibration factors based on both types of road elements (horizontal curves and tangents) led to overestimating and underestimating the number of crashes on tangents and horizontal curves, respectively. Furthermore, the calibration factors based on fatal-and-injury crashes allowed a more accurate estimation of the predicted number of crashes than those calibrated considering all severity levels. Therefore, it is recommended to apply a different calibration factors for each type of road element and each type of crash severity.This research was subsidized by the Spanish Ministry of Economy, Industry, and Competitiveness through "Ayudas a la movilidad predoctoral para la realizacion de estancias breves en centros de I+D 2016." In addition, the authors would like to thank the North Carolina Department of Transportation (NCDOT), which provided traffic and crash data.Llopis-Castelló, D.; Findley, DJ. (2019). Influence of Calibration Factors on Crash Prediction on Rural Two-Lane, Two-Way Roadway Segments. Journal of Transportation Engineering. 145(6):04019024-1-04019024-9. https://doi.org/10.1061/JTEPBS.000024504019024-104019024-9145

    TVNS IMPORVES EMOTION RECOGNITION ACCURACY

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    Growing evidence suggests that vagus nerve activity is an important aspect of social functioning. For instance, vagus nerve activity is linked to positive emotions, low-arousal states, social approach motivations, and emotion recognition, expression, and regulation. By modifying a relatively new manipulation technique – transcutaneous vagus nerve stimulation (tVNS) – we experimentally test the relationship between vagus nerve activity and social functioning, hypothesizing that participants receiving tVNS, compared to sham stimulation, will self-report more positive affect and less arousal, have greater accuracy in emotion recognition, perceive others as more trustworthy and less threatening, and have higher implicit and explicit motivations for social affiliation. One hundred and twenty-six undergraduate students from the University of North Carolina at Chapel Hill participated in this double-blind, placebo-controlled experiment. Results support the hypothesis that tVNS, compared to sham stimulation, improves emotion recognition accuracy. Limitations of the current study as well as the basic and clinical implications of this methodology and initial finding are discussed.Master of Art

    Comparison of the highway safety manual predictive method with safety performance functions based on geometric design consistency

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    This is an Accepted Manuscript of an article published by Taylor & Francis in Journal of Transportation Safety & Security, available online: http://www.tandfonline.com/10.1080/19439962.2020.1738612[EN] Road safety is a major public health concern in our society. Effective road design and accurate safety analyses must be a component of programs focused on reducing and eliminating roadway injuries and deaths. Various methodologies exist to determine the expected number of crashes on rural two-lane rural roads. This research compares different procedures which allow for the estimation of the number of crashes on homogeneous road segments. In this effort, a total of 27 two-lane rural road sections located in North Carolina were considered, resulting in 59 homogeneous road segments composed of 350 horizontal curves and 375 tangents along 150 km of road. Four methods were applied to the selected roadways: the Highway Safety Manual predictive method, two jurisdiction-specific Safety Performance Functions (SPFs), and a SPF which includes a consistency parameter. This research found that the use of SPFs which incorporate a consistency parameter allows highway engineers to consider human factor impacts on road safety assessment. The use of a consistency parameter can also simplify the crash estimation process. Analysis methods which only included local geometric variables provided unreliable results due to the calibration of only the specific road elements instead of their relationship with other road elements along homogeneous road segments.This research was subsidized by the Spanish Ministry of Science, Innovation, and Universities through "Ayudas a la movilidad predoctoral para la realizacion de estancias breves en centros de I+D 2017" (EEBB-I-17-12154) and is part of the research project titled "CASEFU - Estudio experimental de la funcionalidad y seguridad de las carreteras convencionales" (TRA2013-42578-P), subsidized by the above mentioned Spanish Ministry and the European Social Fund. In addition, the authors would like to thank the North Carolina Department of Transportation, which provided traffic and crash data.Llopis-Castelló, D.; Findley, DJ.; García García, A. (2021). Comparison of the highway safety manual predictive method with safety performance functions based on geometric design consistency. Journal of Transportation Safety & Security. 13(12):1365-1386. https://doi.org/10.1080/19439962.2020.1738612S13651386131

    The Association of Participation in a Summer Prelaw Training Program and First-Year Law School Students’ Grades

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    This study estimates the association of participation in a nine-week online educational program to prepare students for post-graduate (juris doctorate) education and law school grades. We collected registrar data from 17 U.S. law schools for participants and non-participants from the same year and a prior year. We compared first-semester law school grades between participating and non-participating students weighted by propensity scores. Course participation was associated with improved first-semester grades in a keyed course (Contracts Law) and overall grade point average. According to pre- and post-survey responses, a substantial portion of those who completed the program reported feeling more prepared for law school

    Toward Integration: From Quantitative Biology to Mathbio-Biomath?

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    In response to the call of BIO2010 for integrating quantitative skills into undergraduate biology education, 30 Howard Hughes Medical Institute (HHMI) Program Directors at the 2006 HHMI Program Directors Meeting established a consortium to investigate, implement, develop, and disseminate best practices resulting from the integration of math and biology. With the assistance of an HHMI-funded mini-grant, led by Karl Joplin of East Tennessee State University, and support in institutional HHMI grants at Emory and University of Delaware, these institutions held a series of summer institutes and workshops to document progress toward and address the challenges of implementing a more quantitative approach to undergraduate biology education. This report summarizes the results of the four summer institutes (2007–2010). The group developed four draft white papers, a wiki site, and a listserv. One major outcome of these meetings is this issue of CBE—Life Sciences Education, which resulted from proposals at our 2008 meeting and a January 2009 planning session. Many of the papers in this issue emerged from or were influenced by these meetings

    Cognitive Behavioral Therapy for Insomnia in Alcohol‐Dependent Veterans: A Randomized, Controlled Pilot Study

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149521/1/acer14030.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149521/2/acer14030-sup-0001-FigS1-S3.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149521/3/acer14030_am.pd

    What drives Senegalese migration to Europe? The role of economic restructuring, labor demand, and the multiplier effect of networks

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    Background: International migration from Sub-Saharan Africa to Europe is poorly understood. Furthermore, existing studies pay insufficient attention to the links between the micro-level factors and political, social, and economic processes in both origin and destination areas. Here we integrate insights from institutional approaches in migration and development research with perspectives that highlight the role of labor market and social capital. Objective: We analyze the contextual and individual-level determinants of migration from Senegal to France, Italy, and Spain since the mid-1970s. We examine the following hypotheses: (1) In Senegal, the deterioration of living conditions and heightened economic insecurity have created the conditions for increasing out-migration propensities. (2) In Europe, labor market restructuring has increased job opportunities in particular places and job niches. (3) In facilitating access of Senegalese migrants to jobs in Europe, social networks have linked these two processes. (4) The conjunction of periods of strong labor demand and the availability of personal networks in Europe creates a boosting effect on the migration probabilities of the Senegalese to Europe. Methods: We use event history models to analyze life course data from the Migrations between Africa and Europe survey (2008). Results: Our empirical results concerning both individual socioeconomic indicators and contextual indicators provide consistent support for the four hypotheses proposed. Conclusions: The initiation and expansion of migration between Senegal and Europe stem from the simultaneous presence of several key factors at origin and destination, including processes of economic restructuring and the mutually reinforcing process of social capital formation and changing labor market conditions. These factors are historically contingent, but they may have a wider relevance in the explanation of migration from developing countries to developed countries

    Feigned Consensus: Usurping the Law in Shaken Baby Syndrome/Abusive Head Trauma Prosecutions

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    Few medico-legal matters have generated as much controversy--both in the medical literature and in the courtroom--as Shaken Baby Syndrome (SBS), now known more broadly as Abusive Head Trauma (AHT). The controversies are of enormous significance in the law because child abuse pediatricians claim, on the basis of a few non-specific medical findings supported by a weak and methodologically flawed research base, to be able to “diagnose” child abuse, and thereby to provide all of the evidence necessary to satisfy all of the legal elements for criminal prosecution (or removal of children from their parents). It is a matter, therefore, in which medical opinion claims to fully occupy the legal field. As controversies flare up increasingly in the legal arena, child abuse pediatricians and prosecutors now respond by claiming both that there is actually no real controversy about SBS/AHT, and that it is a purely medical “diagnosis” and not a legal conclusion, so testimony in support of the SBS hypothesis should not be challenged in court. This article, coauthored by four law professors, two physicians, and a physicist, demonstrates that there is very much a live controversy about the SBS/AHT hypothesis and maintains that, under traditional principles of evidence law, physicians should not be permitted to “diagnose” abuse in court (as opposed to identifying specific symptoms or medical findings)

    Land Use Change in a Pericolonial Society: Intensification and Diversification in Ifugao, Philippines Between 1570 and 1800 CE

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    Land use modelling is increasingly used by archaeologists and palaeoecologists seeking to quantify and compare the changing influence of humans on the environment. In Southeast Asia, the intensification of rice agriculture and the arrival of European colonizers have both been seen as major catalysts for deforestation, soil erosion, and biodiversity change. Here we consider the Tuwali-Ifugao people of the Cordillera Central (Luzon, Philippines), who resisted Spanish colonial subjugation from the 16th to the mid-nineteenth century, in part through the development of a world-renowned system of intensive wet-rice terrace agriculture. To quantify changes in how the Tuwali-Ifugao used their environment, we model land use in Old Kiyyangan Village, a long-inhabited settlement, at two timepoints: circa 1570 CE, prior to the Spanish arrival in Luzon, and circa 1800 CE, before the village was sacked by Spanish military expeditions. Our model demonstrates that between 1570 and 1800 the adoption of rice as a staple and the corresponding expansion in terrace agriculture, along with a general diversification of diet and land use, enabled the village’s population to double without increasing total land use area. Further, this major intensification led to the solidification of social hierarchies and occurred without a proportional increase in deforestation
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