Growth of phase-pure, crack-free single crystals and large-grained polycrystals of molybdenum disilicide

High purity molybdenum disilicide crystals are prepared by zone melting sintered compacts. This method yields single crystals or polycrystals free from macrocracks which allow better measurement and evaluation of mechanical properties

Reaching out to culturally and linguistically diverse families: strategies and challenges reported by parent training and information center staff

Within special education policy and practice, parents are expected to advocate for their children to receive appropriate special education and related services. However, the majority of parents report feeling disempowered to advocate; families from culturally and linguistically diverse (CLD) backgrounds may feel especially disempowered. Federally funded Parent Training and Information Centers (PTIs) exist in each state to empower historically underserved (including CLD) parents of children with disabilities. In this study, we examined how PTIs educate and empower CLD families through semi-structured interviews with 13 PTI staff members who work with CLD families across five states. The participants emphasized the importance of strategies such as conducting outreach in local communities and developing parent leaders among the CLD families they support. The findings also indicated that PTIs struggle with addressing external, systemic barriers which influence CLD families. Implications for research, policy, and practice are discussed.Accepted manuscrip

Improving Visual Field Examination of the Macula Using Structural Information

Purpose: To investigate a novel approach for structure-function modeling in glaucoma to improve visual field testing in the macula. Methods: We acquired data from the macular region in 20 healthy eyes and 31 with central glaucomatous damage. Optical coherence tomography (OCT) scans were used to estimate the local macular ganglion cell density. Perimetry was performed with a fundus-tracking device using a 10-2 grid. OCT scans were matched to the retinal image from the fundus perimeter to accurately map the tested locations onto the structural damage. Binary responses from the subjects to all presented stimuli were used to calculate the structure-function model used to generate prior distributions for a ZEST (Zippy Estimation by Sequential Testing) Bayesian strategy. We used simulations based on structural and functional data acquired from an independent dataset of 20 glaucoma patients to compare the performance of this new strategy, structural macular ZEST (MacS-ZEST), with a standard ZEST. Results: Compared to the standard ZEST, MacS-ZEST reduced the number of presentations by 13% in reliable simulated subjects and 14% with higher rates (≥20%) of false positive or false negative errors. Reduction in mean absolute error was not present for reliable subjects but was gradually more important with unreliable responses (≥10% at 30% error rate). Conclusions: Binary responses can be modeled to incorporate detailed structural information from macular OCT into visual field testing, improving overall speed and accuracy in poor responders. Translational Relevance: Structural information can improve speed and reliability for macular testing in glaucoma practice

Back and forth from cool core to non-cool core: clues from radio-halos

X-ray astronomers often divide galaxy clusters into two classes: "cool core" (CC) and "non-cool core" (NCC) objects. The origin of this dichotomy has been the subject of debate in recent years, between "evolutionary" models (where clusters can evolve from CC to NCC, mainly through mergers) and "primordial" models (where the state of the cluster is fixed "ab initio" by early mergers or pre-heating). We found that in a well-defined sample (clusters in the GMRT Radio halo survey with available Chandra or XMM-Newton data), none of the objects hosting a giant radio halo can be classified as a cool core. This result suggests that the main mechanisms which can start a large scale synchrotron emission (most likely mergers) are the same that can destroy CC and therefore strongly supports "evolutionary" models of the CC-NCC dichotomy. Moreover combining the number of objects in the CC and NCC state with the number of objects with and without a radio-halo, we estimated that the time scale over which a NCC cluster relaxes to the CC state, should be larger than the typical life-time of radio-halos and likely shorter than about 3 Gyr. This suggests that NCC transform into CC more rapidly than predicted from the cooling time, which is about 10 Gyr in NCC systems, allowing the possibility of a cyclical evolution between the CC and NCC states.Comment: Accepted for publication in A&

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Single crystal boules of molybdenum disilicide for performing static fatigue test

Mass profiles and concentration-dark matter relation in X-ray luminous galaxy clusters

(Abriged) Assuming that the hydrostatic equilibrium holds between the intracluster medium and the gravitational potential, we constrain the NFW profiles in a sample of 44 X-ray luminous galaxy clusters observed with XMM-Newton in the redshift range 0.1-0.3. We evaluate several systematic uncertainties that affect our reconstruction of the X-ray masses. We measure the concentration c200, the dark mass M200 and the gas mass fraction within R500 in all the objects of our sample, providing the largest dataset of mass parameters for galaxy clusters in this redshift range. We confirm that a tight correlation between c200 and M200 is present and in good agreement with the predictions from numerical simulations and previous observations. When we consider a subsample of relaxed clusters that host a Low-Entropy-Core (LEC), we measure a flatter c-M relation with a total scatter that is lower by 40 per cent. From the distribution of the estimates of c200 and M200, with associated statistical (15-25%) and systematic (5-15%) errors, we use the predicted values from semi-analytic prescriptions calibrated through N-body numerical runs and measure sigma_8*Omega_m^(0.60+-0.03)= 0.45+-0.01 (at 2 sigma level, statistical only) for the subsample of the clusters where the mass reconstruction has been obtained more robustly, and sigma_8*Omega_m^(0.56+-0.04) = 0.39+-0.02 for the subsample of the 11 more relaxed LEC objects. With the further constraint from the fgas distribution in our sample, we break the degeneracy in the sigma_8-Omega_m plane and obtain the best-fit values sigma_8~1.0+-0.2 (0.75+-0.18 when the subsample of the more relaxed objects is considered) and Omega_m = 0.26+-0.01.Comment: 21 pages. A&A in press. Minor revisions to match accepted version. Corrected 2nd and 3rd column in Table 3, and equation (A.4

Understanding decision making among individuals With Intellectual and Developmental Disabilities (IDD) and their siblings

Many siblings anticipate fulfilling caregiving roles for their brothers and sisters with intellectual and developmental disabilities (IDD). Given these roles and the importance of supported decision-making, it is crucial to understand how individuals with IDD and their siblings make decisions. Using dyadic interviews, we examined the perspectives of nine sibling dyads (N = 18) about decision-making in relation to self-determination, independent living, and employment. The ages of participants ranged from 19 to 57. Data were analyzed using constant comparative analysis to identify themes. Decision-making was characterized by: parents and siblings primarily identifying courses of action; the probability of respective consequences based on the person-environment fit; and the role of the sibling in making the final decision. Characteristics related to the individual with IDD, the family, the sibling, and the environment impacted decision-making. Individuals with IDD were more likely to make their own decisions about leisure activities, however, siblings were more likely to make formal decisions for their brothers and sisters.Accepted manuscrip