3,163 research outputs found
Recommended from our members
Essential tremor associated with pathologic changes in the cerebellum
Background: Although essential tremor (ET) is one of the most common neurologic disorders, there have been few postmortem studies. We recently reported postmortem changes (torpedoes and Bergmann gliosis) in the cerebellar cortex in a few ET cases. Objective: To describe more extensive postmortem changes in the cerebellum in another ET case. Design: Case report. Results: A 90-year-old woman had a 30-year history of ET. At postmortem examination, there was segmental loss of Purkinje cells, presence of torpedoes, and Bergmann gliosis in the cerebellar cortex. Moreover, there were extensive changes in the dentate nucleus, in the form of neuronal loss, neuronal atrophy, microglial clusters, and reduction in the number of efferent fibers (ie, pallor of the hilum). Conclusions: The brain in the current case exhibited more marked cerebellar pathologic features than noted in previously reported ET cases and thereby extends the described cerebellar findings in this common, yet pathologically poorly characterized, neurologic disorder
Gravitation: Global Formulation and Quantum Effects
A nonintegrable phase-factor global approach to gravitation is developed by
using the similarity of teleparallel gravity with electromagnetism. The phase
shifts of both the COW and the gravitational Aharonov-Bohm effects are
obtained. It is then shown, by considering a simple slit experiment, that in
the classical limit the global approach yields the same result as the
gravitational Lorentz force equation of teleparallel gravity. It represents,
therefore, the quantum mechanical version of the classical description provided
by the gravitational Lorentz force equation. As teleparallel gravity can be
formulated independently of the equivalence principle, it will consequently
require no generalization of this principle at the quantum level.Comment: Latex (IOP style), 14 pages, 3 figures. To appear in Classical and
Quantum Gravit
Persistent starspot signals on M dwarfs: multi-wavelength Doppler observations with the Habitable-zone Planet Finder and Keck/HIRES
Young, rapidly-rotating M dwarfs exhibit prominent starspots, which create
quasiperiodic signals in their photometric and Doppler spectroscopic
measurements. The periodic Doppler signals can mimic radial velocity (RV)
changes expected from orbiting exoplanets. Exoplanets can be distinguished from
activity-induced false positives by the chromaticity and long-term incoherence
of starspot signals, but these qualities are poorly constrained for
fully-convective M stars. Coherent photometric starspot signals on M dwarfs may
persist for hundreds of rotations, and the wavelength dependence of starspot RV
signals may not be consistent between stars due to differences in their
magnetic fields and active regions. We obtained precise multi-wavelength RVs of
four rapidly-rotating M dwarfs (AD Leo, G 227-22, GJ 1245B, GJ 3959) using the
near-infrared (NIR) Habitable-zone Planet Finder, and the optical Keck/HIRES
spectrometer. Our RVs are complemented by photometry from Kepler, TESS, and the
Las Cumbres Observatory (LCO) network of telescopes. We found that all four
stars exhibit large spot-induced Doppler signals at their rotation periods, and
investigated the longevity and optical-to-NIR chromaticity for these signals.
The phase curves remain coherent much longer than is typical for Sunlike stars.
Their chromaticity varies, and one star (GJ 3959) exhibits optical and NIR RV
modulation consistent in both phase and amplitude. In general, though, we find
that the NIR amplitudes are lower than their optical counterparts. We conclude
that starspot modulation for rapidly-rotating M stars frequently remains
coherent for hundreds of stellar rotations, and gives rise to Doppler signals
that, due to this coherence, may be mistaken for exoplanets.Comment: Accepted for publication in the Astrophysical Journa
The First Extrasolar Planet Discovered with a New Generation High Throughput Doppler Instrument
We report the detection of the first extrasolar planet, ET-1 (HD 102195b),
using the Exoplanet Tracker (ET), a new generation Doppler instrument. The
planet orbits HD 102195, a young star with solar metallicity that may be part
of the local association. The planet imparts radial velocity variability to the
star with a semiamplitude of m s and a period of 4.11 days.
The planetary minimum mass () is .Comment: 42 pages, 11 figures and 5 tables, Accepted for publication in Ap
Pioglitazone for secondary prevention after ischemic stroke and transient ischemic attack: Rationale and design of the Insulin Resistance Intervention after Stroke Trial
Background: Recurrent vascular events remain a major source of morbidity and mortality after stroke or transient ischemic attack (TIA). The IRIS Trial is evaluating an approach to secondary prevention based on the established association between insulin resistance and increased risk for ischemic vascular events. Specifically, IRIS will test the effectiveness of pioglitazone, an insulin-sensitizing drug of the thiazolidinedione class, for reducing the risk for stroke and myocardial infarction (MI) among insulin resistant, nondiabetic patients with a recent ischemic stroke or TIA. Design: Eligible patients for IRIS must have had insulin resistance defined by a Homeostasis Model Assessment-Insulin Resistance \u3e3.0 without meeting criteria for diabetes. Within 6 months of the index stroke or TIA, patients were randomly assigned to pioglitazone (titrated from 15 to 45 mg/d) or matching placebo and followed for up to 5 years. The primary outcome is time to stroke or MI. Secondary outcomes include time to stroke alone, acute coronary syndrome, diabetes, cognitive decline, and all-cause mortality. Enrollment of 3,876 participants from 179 sites in 7 countries was completed in January 2013. Participant follow-up will continue until July 2015. Summary: The IRIS Trial will determine whether treatment with pioglitazone improves cardiovascular outcomes of nondiabetic, insulin-resistant patients with stroke or TIA. Results are expected in early 2016
Recommended from our members
Seeking and accessing professional support for child anxiety in a community sample
There is a lack of current data on help-seeking, and barriers to accessing professional support for child anxiety disorders. This study aimed to provide current data on the frequency and type of parental help-seeking, professional support received, and parent-reported barriers/facilitators in the context of child anxiety, and to explore factors associated with help-seeking, and parent-reported barriers among help-seekers and non help-seekers. We conducted a survey of help-seeking in parents of 222 children (aged 7-11) with elevated anxiety symptoms identified through screening in schools, 138 children of whom met diagnostic criteria for an anxiety disorder. Almost two-thirds (64.5%) of parents of children with an anxiety disorder reported seeking help from a professional; in 38.4% of cases parents reported that their child had received support from a professional to help manage and overcome their anxiety difficulties, and < 3% had received evidence-based treatment (CBT). Frequently reported parental barriers related to difficulties differentiating between developmentally appropriate and clinically significant anxiety, a lack of help-seeking knowledge, perceived negative consequences of help-seeking, and limited service provision. Non-help seekers were more likely than help seekers to report barriers related to thinking a child's anxiety may improve without professional support, and the absence of professional recognition. Findings identify the need for (i) tools for parents and primary school staff to help identify children who may benefit from professional support to overcome difficulties with anxiety; and (ii) increased evidence-based provision for child anxiety disorders, including delivery within schools and direct support for parents
Evidence synthesis as the basis for decision analysis: a method of selecting the best agricultural practices for multiple ecosystem services
Agricultural management practices have impacts not only on crops and livestock, but also on soil, water, wildlife, and ecosystem services. Agricultural research provides evidence about these impacts, but it is unclear how this evidence should be used to make decisions. Two methods are widely used in decision making: evidence synthesis and decision analysis. However, a system of evidence-based decision making that integrates these two methods has not yet been established. Moreover, the standard methods of evidence synthesis have a narrow focus (e.g., the effects of one management practice), but the standard methods of decision analysis have a wide focus (e.g., the comparative effectiveness of multiple management practices). Thus, there is a mismatch between the outputs from evidence synthesis and the inputs that are needed for decision analysis. We show how evidence for a wide range of agricultural practices can be reviewed and summarized simultaneously (“subject-wide evidence synthesis”), and how this evidence can be assessed by experts and used for decision making (“multiple-criteria decision analysis”). We show how these methods could be used by The Nature Conservancy (TNC) in California to select the best management practices for multiple ecosystem services in Mediterranean-type farmland and rangeland, based on a subject-wide evidence synthesis that was published by Conservation Evidence (www.conservationevidence.com). This method of “evidence-based decision analysis” could be used at different scales, from the local scale (farmers deciding which practices to adopt) to the national or international scale (policy makers deciding which practices to support through agricultural subsidies or other payments for ecosystem services). We discuss the strengths and weaknesses of this method, and we suggest some general principles for improving evidence synthesis as the basis for multi-criteria decision analysis
Percepção de autoeficácia, assertividade sexual e uso do preservativo em jovens colombianos
El uso correcto y consistente del condón en las relaciones sexuales es un procedimiento altamente eficaz para la prevención del VIH/SIDA, así como para otras infecciones de transmisión sexual (ITS). Algunos estudios reportan que las habilidades psicosociales y de interrelación favorecen el desarrollo de prácticas sexuales protegidas, como con el uso de preservativos. El objetivo del presente estudio fue determinar en qué medida la percepción de autoeficacia y la asertividad sexual predicen el uso del condón en las relaciones sexuales en un grupo de jóvenes. Se realizó un estudio descriptivo correlacional y predictivo con una muestra de 631 jóvenes con edades entre 19 y 26 años que reportaron haber tenido relaciones o ser activos sexualmente. Los resultados muestran que la percepción de autoeficacia y la asertividad sexual fueron fuertes predictores del uso del condón en las relaciones sexuales de las mujeres, mientras que para el caso de los hombres, solo la asertividad sexual predijo su uso.O uso correto e consistente do preservativo nas relações sexuais é um procedimento altamente eficaz para a prevenção do HIV/ Aids, bem como para outras infecções de transmissão sexual (ITS). Alguns estudos mostram que as habilidades psicossociais e de inter-relação favorecem o desenvolvimento de práticas sexuais protegidas, como com o uso do preservativo. O objetivo do presente estudo foi determinar em que medida a percepção de autoeficácia e a assertividade sexual predizem o uso do preservativo nas relações sexuais em um grupo de jovens. Realizou-se um estudo descritivo correlacional e preditivo com uma amostra de 631 jovens com idades entre 19 e 26 anos que relataram ter tido relações ou ser ativos sexualmente. Os resultados mostram que a percepção de autoeficácia e a assertividade sexual foram fortes indicadores do uso do preservativo nas relações sexuais das mulheres, enquanto para o caso dos homens, só a assertividade sexual predisse seu uso.The correct and consistent use of condoms during sexual intercourse is a highly effective procedure for the prevention of HIV / AIDS as well as other sexually transmitted infections (STIs). Some studies report that psychosocial skills and interaction promote the development of safe sexual relations by using condoms. The objective of this study was to determine to what extent the perception of self-efficacy and sexual assertiveness predicts condom use in sexual activity in a group of young people. The study was descriptive correlational and predictive.The sample consisted of 645 young people aged between 19 and 26 years who reported having had sex or being sexually active. Results showed that, unlike men, the perception of selfefficacy coupled with sexual assertiveness are strong predictors of condom use in women's sexual relations, whereas for men only sexual assertiveness predicts condom use in sexual relations
Persistent Starspot Signals on M Dwarfs: Multiwavelength Doppler Observations with the Habitable-zone Planet Finder and Keck/HIRES
Young, rapidly rotating M dwarfs exhibit prominent starspots, which create quasiperiodic signals in their photometric and Doppler spectroscopic measurements. The periodic Doppler signals can mimic radial velocity (RV) changes expected from orbiting exoplanets. Exoplanets can be distinguished from activity-induced false positives by the chromaticity and long-term incoherence of starspot signals, but these qualities are poorly constrained for fully convective M stars. Coherent photometric starspot signals on M dwarfs may persist for hundreds of rotations, and the wavelength dependence of starspot RV signals may not be consistent between stars due to differences in their magnetic fields and active regions. We obtained precise multiwavelength RVs of four rapidly rotating M dwarfs (AD Leo, G227-22, GJ 1245B, GJ 3959) using the near-infrared (NIR) Habitable-zone Planet Finder and the optical Keck/HIRES spectrometer. Our RVs are complemented by photometry from Kepler, TESS, and the Las Cumbres Observatory network of telescopes. We found that all four stars exhibit large spot-induced Doppler signals at their rotation periods, and investigated the longevity and optical-to-NIR chromaticity for these signals. The phase curves remain coherent much longer than is typical for Sunlike stars. Their chromaticity varies, and one star (GJ 3959) exhibits optical and NIR RV modulation consistent in both phase and amplitude. In general, though, we find that the NIR amplitudes are lower than their optical counterparts. We conclude that starspot modulation for rapidly rotating M stars frequently remains coherent for hundreds of stellar rotations and gives rise to Doppler signals that, due to this coherence, may be mistaken for exoplanets
- …