2,489 research outputs found
An Excess of Jupiter Analogs in Super-Earth Systems
We use radial velocity observations to search for long-period gas giant
companions in systems hosting inner super-Earth (1-4 R_Earth, 1-10 M_Earth)
planets to constrain formation and migration scenarios for this population. We
consistently re-fit published RV datasets for 65 stars and find 9 systems with
statistically significant trends indicating the presence of an outer companion.
We combine these RV data with AO images to constrain the masses and semi-major
axes of these companions. We quantify our sensitivity to the presence of
long-period companions by fitting the sample with a power law distribution and
find an occurrence rate of 39+/-7% for companions 0.5-20 M_Jup and 1-20 AU.
Half of our systems were discovered by the transit method and half were
discovered by the RV method. While differences in RV baselines and number of
data points between the two samples lead to different sensitivities to distant
companions, we find that occurrence rates of gas giant companions in each
sample are consistent at the 0.5 level. We compare the frequency of
Jupiter analogs in these systems to the equivalent rate from field star surveys
and find that Jupiter analogs are more common around stars hosting
super-Earths. We conclude that the presence of outer gas giants does not
suppress the formation of inner super-Earths, and that these two populations of
planets instead appear to be correlated. We also find that the stellar
metallicities of systems with gas giant companions are higher than those
without companions, in agreement with the well-established metallicity
correlation from RV surveys of field stars.Comment: published in A
Items on a Perceived Environment Tool are Grouped Differently in Low and High Income African American Women
Purpose: Prevalence of physical inactivity is greater in African American (AA) women than any other population sub group. The neighborhood environment is an important influence on physical activity, and accurate measurement of neighborhood perceptions is needed to determine the influence of neighborhood environment on physical activity. The purpose of this study was to investigate the stability of constructs represented by items from the International Prevalence Study (IPS) environmental module among high and low income AA women. Method: African American women (N=387) completed the IPS environmental module questionnaire which measured perception of neighborhood environment. A principle component analysis with varimax rotation was conducted using fifteen of seventeen items from the survey. Factor analysis was conducted separately for high and low income participants. Results: Four factors with eigenvalues ≥ 1.0 were extracted from the 15 item questionnaire for both groups. These four factors accounted for 56.6% of total variance in the high income group, and 53.1% of total variance in the low income group. The four factors for the high income group were Aesthetic Qualities and Social Environment, Neighborhood Safety, Neighborhood Infrastructure, and Destinations and Street Connectivity. The four factors for the low income group were Aesthetic Qualities and Social Environment, Neighborhood Safety, Opportunities to be active and Street Connectivity, and Public Transportation. Conclusion: The factors extracted for high and low income AA women may have been different due to dissimilarities in neighborhood infrastructure, design and quality. Inconsistent grouping of items into factors from the same instrument used to measure perceptions of neighborhood environment underscores the importance of accounting for differences in how high and low income residents perceive their neighborhood when considering physical activity interventions and policies
Fast Food and Supermarket Availability, Neighborhood Income and Health Outcomes in Public Housing Residents.
Purpose: The availability of fast food restaurants (FFRs) and supermarkets varies by neighborhood income level and may influence health outcomes such as body mass index (BMI) and blood pressure (BP). The purpose of this study was to determine whether neighborhood income moderates the association between fast food restaurant or supermarket availability and health outcomes in public housing residents. Method: Number of FFRs and supermarkets on every street segment in neighborhoods surrounding public housing developments (N=12) in Houston, Texas were counted, then aggregated at the neighborhood level. Residents (N=213) completed measures of BMI (kg/m2) and resting BP. Median household income at the census block level for each housing development was obtained from the 2006-2010 American Community Survey. Linear regression models determined whether availability of fast food restaurants and supermarkets predicts BMI or BP after controlling for age and gender, and if neighborhood income moderated these associations. Results: Participants were middle aged (M=43.5±17.1 years) females (n=138) and males (n=75). BP did not differ by gender (M=121.5/74.0±17.5/12.8 mmHg), females were on average obese (MBMI=33.0±8.7kg/ m2) and males were overweight (MBMI=33.0±8.7kg/ m2). Neighborhood income ranged from 57,618. There were (M=.003±.03) FFRs per neighborhood and (M=.001±.008) supermarkets per neighborhood. Bivariate correlations found that neighborhood income was associated with fast food restaurant (r=.205, p.05). Income did not moderate these associations (p\u3e.05). Conclusions: BP changes with age, and BMI varies by gender. After controlling for these variables, fast food restaurant and supermarket availability did not predict BMI or BP in public housing residents, and neighborhood income did not affect the direction of these associations. Actual consumption of the foods sold at these places may have a more direct relationship with health outcomes. Limited variability in the number of FFRs and supermarkets in each neighborhood may have diminished our ability to detect an effect of these neighborhood factors on BMI and BP
The California Legacy Survey IV. Lonely, Poor, and Eccentric: A Comparison Between Solitary and Neighborly Gas Giants
We compare systems with single giant planets to systems with multiple giant
planets using a catalog of planets from a high-precision radial velocity survey
of FGKM stars. Our comparison focuses on orbital properties, planet masses, and
host star properties. We use hierarchical methods to model the orbital
eccentricity distributions of giant singles and giant multis, and find that the
distributions are distinct. The multiple giant planets typically have moderate
eccentricities and their eccentricity distribution extends to (90th
percentile), while the single giant planets have a pile-up of nearly circular
orbits and a long tail that extends to . We determine that stellar
hosts of multiple giants are distinctly more metal-rich than hosts of solitary
giants, with respective mean metallicities vs.
dex. We measure the distinct occurrence distributions of single and multiple
giants with respect to orbital separation, and find that single gas giants have
a 2.3 significant hot () Jupiter pile-up not seen among
multi giant systems. We find that the median mass (\msini ) of giants in
multiples is nearly double that of single giants (1.71 \mjup vs. 0.92 \mjup
). We find that giant planets in the same system have correlated masses,
analogous to the `peas in a pod' effect seen among less massive planets
Best Practices and Considerations: Including Young Children with Disabilities in Early Childhood Settings
Best Practices and Considerations: Including Young Children with Disabilities in Early Childhood Settings
Designer Reagents for Mass Spectrometry-Based Proteomics: Clickable Cross-Linkers for Elucidation of Protein Structures and Interactions
We present novel homobifunctional amine-reactive clickable cross-linkers (CXLs) for investigation of three-dimensional protein structures and protein–protein interactions (PPIs). CXLs afford consolidated advantages not previously available in a simple cross-linker, including (1) their small size and cationic nature at physiological pH, resulting in good water solubility and cell-permeability, (2) an alkyne group for bio-orthogonal conjugation to affinity tags via the click reaction for enrichment of cross-linked peptides, (3) a nucleophilic displacement reaction involving the 1,2,3-triazole ring formed in the click reaction, yielding a lock-mass reporter ion for only clicked peptides, and (4) higher charge states of cross-linked peptides in the gas-phase for augmented electron transfer dissociation (ETD) yields. Ubiquitin, a lysine-abundant protein, is used as a model system to demonstrate structural studies using CXLs. To validate the sensitivity of our approach, biotin-azide labeling and subsequent enrichment of cross-linked peptides are performed for cross-linked ubiquitin digests mixed with yeast cell lysates. Cross-linked peptides are detected and identified by collision induced dissociation (CID) and ETD with linear quadrupole ion trap (LTQ)-Fourier transform ion cyclotron resonance (FTICR) and LTQ-Orbitrap mass spectrometers. The application of CXLs to more complex systems (e.g., in vivo cross-linking) is illustrated by Western blot detection of Cul1 complexes including known binders, Cand1 and Skp2, in HEK 293 cells, confirming good water solubility and cell-permeability
Systematic Literature Review of AbobotulinumtoxinA in Clinical Trials for Lower Limb Spasticity
AbstractTo elucidate clinical trial efficacy, safety, and dosing practices of AbobotulinumtoxinA (ABO) treatment in adult patients with lower limb spasticity.A systematic literature review was performed to identify randomized controlled trials of ABO in the treatment of adult lower limb spasticity.Of the 295 records identified, 6 primary publications evaluated ABO for the management of lower limb spasticity of various etiologies and were evaluated. Total ABO doses ranged between 500 and 2000 U for lower limb spasticity, depending on the muscles injected. All studies in lower limb spasticity showed statistically significant reduction in muscle tone based on Modified Ashworth Scale of ABO versus placebo. Significant effects on active movement and pain were demonstrated albeit less consistently. ABO was generally well tolerated across the individual studies; most adverse events reported were considered unrelated to treatment. Treatment-related adverse events included but not limited to fatigue, local pain at injection site, hypertonia, dry mouth, weakness of the noninjected muscle, abnormal gait, and urinary tract infection.These data from 6 randomized clinical studies provide the beginnings of an evidence base for the use of ABO to reduce lower limb spasticity. Ongoing studies in this area will add to this evidence base
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