School-based interventions are thought to be the most universally applicable and effective way to counteract low physical activity (PA) and fitness although there is controversy about the optimal strategy to intervene. The objective of this review was therefore to summarize recent reviews with the aim of increasing PA or fitness in youth and carry out a systematic review of new intervention studies. Relevant systematic reviews and original controlled and randomized controlled schoolbased trials with a PA or fitness outcome measure, a duration of ≥12 weeks, a sufficient quality and involvement of a healthy (non-clinical) population aged 6-18 years that were published from 2007-2010 were included. In these reviews, 47-65% of trials were found to be effective. The effect was mostly seen in school-related PA while effects outside school were often not observed or assessed. The school-based application of multicomponent intervention strategies was the most consistent promising intervention strategy, while controversy existed regarding the effectiveness of family involvement, focus on healthy populations at increased risk, or duration and intensity of the intervention. All 20 trials fulfilling the inclusion criteria in the review update showed a positive effect on in-school, out-of-school or overall PA, and 6 of 11 studies showed an increase in fitness. Taking into consideration both assessment quality and Public Health relevance, multicomponent approaches in children including family components showed the highest level of evidence for increasing overall PA. This review confirms the Public Health potential of high quality school-based PA interventions for increasing PA and possibly fitness in healthy children and adolescents.
We present final Spitzer trigonometric parallaxes for 361 L, T, and Y dwarfs. We combine these with prior studies to build a list of 525 known L, T, and Y dwarfs within 20 pc of the Sun, 38 of which are presented here for the first time. Using published photometry and spectroscopy as well as our own follow-up, we present an array of colormagnitude and color-color diagrams to further characterize census members, and we provide polynomial fits to the bulk trends. Using these characterizations, we assign each object a T eff value and judge sample completeness over bins of T eff and spectral type. Except for types T8 and T eff < 600 K, our census is statistically complete to the 20 pc limit. We compare our measured space densities to simulated density distributions and find that the best fit is a power law ( µ a -dN dM M ) with α = 0.6 ± 0.1. We find that the evolutionary models of Saumon & Marley correctly predict the observed magnitude of the space density spike seen at 1200 K < T eff < 1350 K, believed to be caused by an increase in the cooling timescale across the L/T transition. Defining the low-mass terminus using this sample requires a more statistically robust and complete sample of dwarfs Y0.5 and with T eff < 400 K. We
We present preliminary trigonometric parallaxes of 184 late-T and Y dwarfs using observations from Spitzer (143), USNO (18), NTT (14), and UKIRT (9). To complete the 20-pc census of ≥T6 dwarfs, we combine these measurements with previously published trigonometric parallaxes for an additional 44 objects and spectrophotometric distance estimates for another 7. For these 235 objects, we estimate temperatures, sift into five 150K-wide T eff bins covering the range 300-1050K, determine the completeness limit for each, and compute space densities. To anchor the high-mass end of the brown dwarf mass spectrum, we compile a list of earlyto mid-L dwarfs within 20 pc. We run simulations using various functional forms of the mass function passed through two different sets of evolutionary code to compute predicted distributions in T eff . The best fit of these predictions to our L, T, and Y observations is a simple power-law model with α ≈ 0.6 (where dN/dM ∝ M −α ), meaning that the slope of the field substellar mass function is in rough agreement with that found for brown dwarfs in nearby star forming regions and young clusters. Furthermore, we find that published versions of the log-normal form do not predict the steady rise seen in the space densities from 1050K to 350K. We also find that the low-mass cutoff to formation, if one exists, is lower than ∼5 M Jup , which corroborates findings in young, nearby moving groups and implies that extremely low-mass objects have been forming over the lifetime of the Milky Way.
Objective: To examine neuropsychological measures among normal individuals that predict time to subsequent cognitive decline.Design: Cognitive performance, as measured by 6 neuropsychological tests, was examined at baseline. Participants were followed up for approximately 5 years. Cox proportional hazards models were used to evaluate the neuropsychological measures at baseline that predicted time to progression from normal cognition to mild impairment. Comparable data also examined time to progression from mild impairment to a diagnosis of Alzheimer disease.Setting: Community volunteer-based sample examined at a medical institution. Participants: One hundred and seven individuals who were cognitively normal and 235 individuals with mild cognitive impairment at baseline. Main Outcome Measures: Time to progression from normal cognition to mild impairment and time to progression from mild impairment to a diagnosis of Alzheimer disease.Results: The risk of progressing from normal to mild impairment was considerably greater among those with
The term "neurolymphomatosis" (NL) has included infiltration of the peripheral nervous system by lymphoma and nontumor lymphocytes. We describe NL as a lymphoma entity that affects cranial and peripheral nerves and roots. We reviewed the medical records of patients at the Massachusetts General Hospital (MGH) who registered between 1972 and 2000, as well as cases published in the English-language literature. Inclusion criteria were (A) histopathologic demonstration of lymphoma within peripheral nerve, nerve root/plexus, or cranial nerve or (B) CT/MRI or intraoperative evidence of nerve enlargement and/or enhancement beyond the dural sleeve in the setting of prior or concurrent lymphoma in systemic or CNS sites. We identified 25 patients with NL in addition to 47 reported by others. Four clinical presentations were (1) painful involvement of nerves or roots, (2) cranial neuropathy with or without pain, (3) painless involvement of peripheral nerves, (4) painful or painless involvement of a single peripheral nerve. Twenty of our patients and 44 of those reported had histopathologic confirmation of lymphoma infiltrating root or nerve. In the remainder, diagnosis was based upon clinical presentation, nodular nerve enlargement or enhancement, and lymphoma cells in spinal fluid or extraneural sites. For antemortem diagnosis, imaging studies were of greatest utility, followed by biopsy. Thirty-three patients of the combined series were not correctly diagnosed until postmortem examination. Systemic chemotherapy was used to address the multiple potential sites of involvement. When properly treated, NL carries a prognosis similar to primary CNS lymphoma in the modern era.
Orbiting planets induce a weak radial velocity (RV) shift in the host star that provides a powerful method of planet detection. Importantly, the RV technique provides information about the exoplanet mass, which is unavailable with the complementary technique of transit photometry. However, RV detection of an Earth-like planet in the ‘habitable zone’ 1 requires extreme spectroscopic precision that is only possible using a laser frequency comb (LFC) 2 . Conventional LFCs require complex filtering steps to be compatible with astronomical spectrographs, but a new chip-based microresonator device, the Kerr soliton microcomb 3 – 8 , is an ideal match for astronomical spectrograph resolution and can eliminate these filtering steps. Here, we demonstrate an atomic/molecular line-referenced soliton microcomb as a first in-the-field demonstration of microcombs for calibration of astronomical spectrographs. These devices can ultimately provide LFC systems that would occupy only a few cubic centimetres 9 , 10 , thereby greatly expanding implementation of these technologies into remote and mobile environments beyond the research lab.
We use the AllWISE Data Release to continue our search for WISE-detected motions. In this paper, we publish another 27,846 motion objects, bringing the total number to 48,000 when objects found during our original AllWISE motion survey are included. We use this list, along with the lists of confirmed WISE-based motion objects from the recent papers by Luhman and by Schneider et al. and candidate motion objects from the recent paper by Gagné et al. to search for widely separated, common-proper-motion systems. We identify 1,039 such candidate systems. All 48,000 objects are further analyzed using color-color and color-mag plots to provide possible characterizations prior to spectroscopic follow-up. We present spectra of 172 of these, supplemented with new spectra of 23 comparison objects from the literature, and provide classifications and physical interpretations of interesting sources. Highlights include: (1) the identification of three G/K dwarfs that can be used as standard candles to study clumpiness and grain size in nearby molecular clouds because these objects are currently moving behind the clouds, (2) the confirmation/discovery of several M, L, and T dwarfs and one white dwarf whose spectrophotometric distance estimates place them 5-20 pc from the Sun, (3) the suggestion that the Na I 'D' line be used as a diagnostic tool for interpreting and classifying metal-poor late-M and L dwarfs, (4) the recognition of a triple system including a carbon dwarf and late-M subdwarf, for which model fits of the late-M subdwarf (giving [Fe/H]≈−1.0) provide a measured metallicity for the carbon star, and (5) a possible 24-pc-distant K5 dwarf + peculiar red L5 system with an apparent physical separation of 0.1 pc. a This is the motion measured between the 2MASS and AllWISE epochs. bIf the source is a motion discovery unique to AllWISE, this column is "0". For previous discoveries the column is "1".
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