571 research outputs found
Can intergroup contact affect ingroup dynamics? Insights from a field study with Jewish and Arab-Palestinian youth in Israel
How can intergroup contact programs affect conflict-ridden communities besides improving the outgroup attitudes of participating individuals? We address this question by examining the effects of an intergroup contact intervention on ingroup dynamics that may mitigate intergroup conflict. We also examine how outgroup attitudes and psychological resources mediate such effects. We present the results from a difference-in-differences design with 149 Jewish and Arab-Palestinian youth, some of whom participated in an intergroup contact and sports program operated by a nongovernmental organizations in Israel. Our main outcome is oneâs tendency to censure ingroup membersâ provocations toward the outgroup. As expected, we find a positive impact of the program on ingroup censuring. However, this result is only marginally significant. We find a positive effect of program participation on outgroup attitudes among Jewish youth as expected. To our surprise, among Arab-Palestinian youth, we find a negative effect on outgroup attitudes. Exploring the underlying processes and group-based differences further, we find that outgroup regard mediates the effect of intergroup contact on ingroup censuring for Jewish youth. We find no evidence for mediation among Arab-Palestinian youth but a positive association between ingroup censuring and psychological resources. These results suggest that the psychological conditions of ingroup censuring may differ by group. We discuss implications for peace-building interventions in societies with groups in conflict
Automation of orbit determination functions for National Aeronautics and Space Administration (NASA)-supported satellite missions
The Flight Dynamics Facility (FDF) at Goddard Space Flight Center (GSFC) provides spacecraft trajectory determination for a wide variety of National Aeronautics and Space Administration (NASA)-supported satellite missions, using the Tracking Data Relay Satellite System (TDRSS) and Ground Spaceflight and Tracking Data Network (GSTDN). To take advantage of computerized decision making processes that can be used in spacecraft navigation, the Orbit Determination Automation System (ODAS) was designed, developed, and implemented as a prototype system to automate orbit determination (OD) and orbit quality assurance (QA) functions performed by orbit operations. Based on a machine-resident generic schedule and predetermined mission-dependent QA criteria, ODAS autonomously activates an interface with the existing trajectory determination system using a batch least-squares differential correction algorithm to perform the basic OD functions. The computational parameters determined during the OD are processed to make computerized decisions regarding QA, and a controlled recovery process isactivated when the criteria are not satisfied. The complete cycle is autonomous and continuous. ODAS was extensively tested for performance under conditions resembling actual operational conditions and found to be effective and reliable for extended autonomous OD. Details of the system structure and function are discussed, and test results are presented
Evolution of E2 transition strength in deformed hafnium isotopes from new measurements on Hf, Hf, and Hf
The available data for E2 transition strengths in the region between
neutron-deficient Hf and Pt isotopes are far from complete. More and precise
data are needed to enhance the picture of structure evolution in this region
and to test state-of-the-art nuclear models. In a simple model, the maximum
collectivity is expected at the middle of the major shell. However, for actual
nuclei, this picture may no longer be the case, and one should use a more
realistic nuclear-structure model. We address this point by studying the
spectroscopy of Hf. We remeasure the 2^+_1 half-lives of 172,174,176Hf, for
which there is some disagreement in the literature. The main goal is to
measure, for the first time, the half-lives of higher-lying states of the
rotational band. The new results are compared to a theoretical calculation for
absolute transition strengths. The half-lives were measured using \gamma-\gamma
and conversion-electron-\gamma delayed coincidences with the fast timing
method. For the determination of half-lives in the picosecond region, the
generalized centroid difference method was applied. For the theoretical
calculation of the spectroscopic properties, the interacting boson model is
employed, whose Hamiltonian is determined based on microscopic energy-density
functional calculations. The measured 2^+_1 half-lives disagree with results
from earlier \gamma-\gamma fast timing measurements, but are in agreement with
data from Coulomb excitation experiments and other methods. Half-lives of the
4^+_1 and 6^+_1 states were measured, as well as a lower limit for the 8^+_1
states. We show the importance of the mass-dependence of effective boson charge
in the description of E2 transition rates in chains of nuclei. It encourages
further studies of the microscopic origin of this mass dependence. New data on
transition rates in nuclei from neighboring isotopic chains could support these
studies.Comment: 16 pages, 16 figures, 7 tables; Abstract shortened due to character
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Effects of limonene on ruminal fusobacterium necrophorum concentrations, fermentation, and lysine degradation in cattle
Citation: Samii, S. S., Wallace, N., Nagaraja, T. G., Engstrom, M. A., Miesner, M. D., Armendariz, C. K., & Titgemeyer, E. C. (2016). Effects of limonene on ruminal fusobacterium necrophorum concentrations, fermentation, and lysine degradation in cattle. Journal of Animal Science, 94(8), 3420-3430. doi:10.2527/jas2016-0455Previous in vitro data showed that Fusobacterium necrophorum was inhibited by limonene. We further evaluated effects of limonene on growth of F. necrophorum in vitro as well as on ruminal concentrations of F. necrophorum in vivo. With in vitro cultivation in anaerobic brain-heart infusion broth, limonene decreased growth of F. necrophorum. Thymol also reduced growth of F. necrophorum, but it was less effective than limonene. Tylosin effectively reduced growth of F. necrophorum in vitro. Although the response over fermentation times and concentrations of antimicrobials differed somewhat between tylosin and limonene, the 2 antimicrobial agents yielded similar inhibitory effects on growth of F. necrophorum at concentrations ranging from 6 to 24 mg/L. The effects of limonene on ruminal F. necrophorum concentration in vivo were tested in 7 ruminally cannulated heifers (225 kg initial BW) used in a 7 à 4 Youden square design. Treatments included: 1) control, 2) limonene at 10 mg/kg diet DM, 3) limonene at 20 mg/kg diet DM, 4) limonene at 40 mg/kg diet DM, 5) limonene at 80 mg/kg diet DM, 6) CRINA-L (a blend of essential oil components) at 180 mg/kg diet DM, and 7) tylosin at 12 mg/kg diet DM. Each period included 11 d with 10 d washouts between periods. Samples of ruminal contents were collected before treatment initiation and after 4, 7, and 10 d of treatment for measuring F. necrophorum by the most probable number method using selective culture medium. Limonene linearly decreased (P = 0.03) ruminal F. necrophorum concentration, with the lowest concentration achieved with 40 mg of limonene/kg dietary DM. Limonene tended (P ? 0.07) to linearly reduce ruminal molar proportions of propionate and valerate while tending to linearly increase (P ? 0.10) those of butyrate and 2-methyl butyrate. Limonene did not affect ruminal NH3 concentrations or degradation rates of lysine. Neither CRINA-L (P = 0.52) nor tylosin (P = 0.19) affected ruminal F. necrophorum concentrations. CRINA-L significantly decreased ruminal concentrations of NH3 and molar proportions of 3-methyl butyrate, whereas tylosin significantly decreased molar proportions of propionate while increasing those of butyrate and tending to increase those of acetate. Limonene supplementation reduced ruminal concentrations of F. necrophorum suggesting that it may have the potential to reduce the prevalence of liver abscesses, although further research is needed to assess the effect of limonene in feedlot cattle. © 2016 American Society of Animal Science. All rights reserved
Implementation of an Optimised Cassegrain System for Radio Telescopes
We present the antenna design for a radio interferometer, the Arcminute
Microkelvin Imager, together with its beam pattern measurement. Our aim was to
develop a low-cost system with high aperture efficiency and low ground-spill
across the frequency range 12-18GHz. We use a modified cassegrain system
consisting of a commercially-available paraboloidal primary mirror with a
diameter of 3.7m, and a shaped secondary mirror. The secondary mirror is
oversized with respect to a ray-optics design and has a surface that is bent
towards the primary near its outer edge using a square term for the shaping.
The antennas are simple to manufacture and therefore their cost is low. The
design increased the antenna gain by approximately 10 per cent compared to a
normal Cassegrain system while still maintaining low contamination from
ground-spill and using a simple design for the horn.Comment: 4 pages, 7 figures, to be published in MNRA
The Optical Design and Characterization of the Microwave Anisotropy Probe
The primary goal of the MAP satellite, now in orbit, is to make high fidelity
polarization sensitive maps of the full sky in five frequency bands between 20
and 100 GHz. From these maps we will characterize the properties of the cosmic
microwave background (CMB) anisotropy and Galactic and extragalactic emission
on angular scales ranging from the effective beam size, <0.23 degree, to the
full sky. MAP is a differential microwave radiometer. Two back-to-back shaped
offset Gregorian telescopes feed two mirror symmetric arrays of ten corrugated
feeds. We describe the prelaunch design and characterization of the optical
system, compare the optical models to the measurements, and consider multiple
possible sources of systematic error.Comment: ApJ in press; 22 pages with 11 low resolution figures; paper is
available with higher quality figures at
http://map.gsfc.nasa.gov/m_mm/tp_links.htm
Langerhans cell histiocytosis of the suprasellar region: diagnosis based on thyroid cytology.
Langerhans cell histiocytosis (LCH) may present as unifocal disease of the suprasellar region, with symptoms and signs of hypopituitarism, arginine vasopressin deficiency (AVP-D), and weight gain. Transcranial biopsy is necessary to define diagnosis and guide treatment decisions, but it is associated with significant morbidity. We describe a patient with Hashimoto thyroiditis and a single hypothalamic mass in whom LCH diagnosis was made by thyroid fine-needle aspiration cytology (FNAC) performed despite nonspecific findings in thyroid imaging, on the basis of a slightly elevated [18F]-fluorodeoxyglucose (FDG) avidity on PET/CT and volume increase during follow-up
Neurofibromatosis
Neurofibromatosis (NF) is one of the most common genetic disorders. Inherited in an autosomal dominant fashion, this phacomatosis is classified into two genetically distinct subtypes characterized by multiple cutaneous lesions and tumors of the peripheral and central nervous system. Neurofibromatosis type 1 (NF1), also referred to as Recklinghausen's disease, affects about 1 in 3500 individuals and presents with a variety of characteristic abnormalities of the skin and the peripheral nervous system. Neurofibromatosis type 2 (NF2), previously termed central neurofibromatosis, is much more rare occurring in less than 1 in 25 000 individuals. Often first clinical signs of NF2 become apparent in the late teens with a sudden loss of hearing due to the development of bi-or unilateral vestibular schwannomas. In addition NF2 patients may suffer from further nervous tissue tumors such as meningiomas or gliomas. This review summarizes the characteristic features of the two forms of NF and outlines commonalities and distinctions between NF1 and NF2
Within study comparisons and risk of bias in international development: Systematic review and critical appraisal
Background Many systematic reviews incorporate nonrandomised studies of effects, sometimes called quasiâexperiments or natural experiments. However, the extent to which nonrandomised studies produce unbiased effect estimates is unclear in expectation or in practice. The usual way that systematic reviews quantify bias is through ârisk of bias assessmentâ and indirect comparison of findings across studies using metaâanalysis. A more direct, practical way to quantify the bias in nonrandomised studies is through âinternal replication researchâ, which compares the findings from nonrandomised studies with estimates from a benchmark randomised controlled trial conducted in the same population. Despite the existence of many risks of bias tools, none are conceptualised to assess comprehensively nonrandomised approaches with selection on unobservables, such as regression discontinuity designs (RDDs). The few that are conceptualised with these studies in mind do not draw on the extensive literature on internal replications (withinâstudy comparisons) of randomised trials. Objectives Our research objectives were as follows: Objective 1: to undertake a systematic review of nonrandomised internal study replications of international development interventions. Objective 2: to develop a risk of bias tool for RDDs, an increasingly common method used in social and economic programme evaluation. Methods We used the following methods to achieve our objectives. Objective 1: we searched systematically for nonrandomised internal study replications of benchmark randomised experiments of social and economic interventions in lowâ and middleâincome countries (L&MICs). We assessed the risk of bias in benchmark randomised experiments and synthesised evidence on the relative bias effect sizes produced by benchmark and nonrandomised comparison arms. Objective 2: We used document review and expert consultation to develop further a risk of bias tool for quasiâexperimental studies of interventions (ROBINSâI) for RDDs. Results Objective 1: we located 10 nonrandomised internal study replications of randomised trials in L&MICs, six of which are of RDDs and the remaining use a combination of statistical matching and regression techniques. We found that benchmark experiments used in internal replications in international development are in the main wellâconducted but have âsome concernsâ about threats to validity, usually arising due to the methods of outcomes data collection. Most internal replication studies report on a range of different specifications for both the benchmark estimate and the nonrandomised replication estimate. We extracted and standardised 604 bias coefficient effect sizes from these studies, and present average results narratively. Objective 2: RDDs are characterised by prospective assignment of participants based on a threshold variable. Our review of the literature indicated there are two main types of RDD. The most common type of RDD is designed retrospectively in which the researcher identifies postâhoc the relationship between outcomes and a threshold variable which determines assignment to intervention at pretest. These designs usually draw on routine data collection such as administrative records or household surveys. The other, less common, type is a prospective design where the researcher is also involved in allocating participants to treatment groups from the outset. We developed a risk of bias tool for RDDs. Conclusions Internal study replications provide the grounds on which bias assessment tools can be evidenced. We conclude that existing risk of bias tools needs to be further developed for use by Campbell collaboration authors, and there is a wide range of risk of bias tools and internal study replications to draw on in better designing these tools. We have suggested the development of a promising approach for RDD. Further work is needed on common methodologies in programme evaluation, for example on statistical matching approaches. We also highlight that broader efforts to identify all existing internal replication studies should consider more specialised systematic search strategies within particular literatures; so as to overcome a lack of systematic indexing of this evidence
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