Positronium reflection and positronium beams

Specular reflection of positronium, Ps was observed and that there is adequate intensity at higher energies to make further study worthwhile was established. The scattering appears to be restricted to the outermost surface with a mean free path of (0.75 + or - 0.15)A for Ps in LiF(100). With a greater intensity Ps beam one should see higher order diffraction beams as the result of the periodicity of the surface. Ps diffraction thus offers the possibility of being a novel and valuable probe to study the outermost surface and to study adsorbants on it. Two methods for producing Ps beams are described

Full potential LAPW calculation of electron momentum density and related properties of Li

Electron momentum density and Compton profiles in Lithium along $$,$$, and $$ directions are calculated using Full-Potential Linear Augmented Plane Wave basis within generalized gradient approximation. The profiles have been corrected for correlations with Lam-Platzman formulation using self-consistent charge density. The first and second derivatives of Compton profiles are studied to investigate the Fermi surface breaks. Decent agreement is observed between recent experimental and our calculated values. Our values for the derivatives are found to be in better agreement with experiments than earlier theoretical results. Two-photon momentum density and one- and two-dimensional angular correlation of positron annihilation radiation are also calculated within the same formalism and including the electron-positron enhancement factor.Comment: 11 pages, 7 figures TO appear in Physical Review

Towards an understanding of hole superconductivity

From the very beginning K. Alex M\"uller emphasized that the materials he and George Bednorz discovered in 1986 were $hole$ superconductors. Here I would like to share with him and others what I believe to be $the$ key reason for why high $T_c$ cuprates as well as all other superconductors are hole superconductors, which I only came to understand a few months ago. This paper is dedicated to Alex M\"uller on the occasion of his 90th birthday.Comment: Dedicated to Alex M\"uller on the Occasion of his 90th Birthday. arXiv admin note: text overlap with arXiv:1703.0977

Lorlatinib with or without chemotherapy in ALK-driven refractory/relapsed neuroblastoma: phase 1 trial results.

Neuroblastomas harbor ALK aberrations clinically resistant to crizotinib yet sensitive pre-clinically to the third-generation ALK inhibitor lorlatinib. We conducted a first-in-child study evaluating lorlatinib with and without chemotherapy in children and adults with relapsed or refractory ALK-driven neuroblastoma. The trial is ongoing, and we report here on three cohorts that have met pre-specified primary endpoints: lorlatinib as a single agent in children (12 months to <18 years); lorlatinib as a single agent in adults (≥18 years); and lorlatinib in combination with topotecan/cyclophosphamide in children (<18 years). Primary endpoints were safety, pharmacokinetics and recommended phase 2 dose (RP2D). Secondary endpoints were response rate and 123I-metaiodobenzylguanidine (MIBG) response. Lorlatinib was evaluated at 45-115 mg/m2/dose in children and 100-150 mg in adults. Common adverse events (AEs) were hypertriglyceridemia (90%), hypercholesterolemia (79%) and weight gain (87%). Neurobehavioral AEs occurred mainly in adults and resolved with dose hold/reduction. The RP2D of lorlatinib with and without chemotherapy in children was 115 mg/m2. The single-agent adult RP2D was 150 mg. The single-agent response rate (complete/partial/minor) for <18 years was 30%; for ≥18 years, 67%; and for chemotherapy combination in <18 years, 63%; and 13 of 27 (48%) responders achieved MIBG complete responses, supporting lorlatinib's rapid translation into active phase 3 trials for patients with newly diagnosed high-risk, ALK-driven neuroblastoma. ClinicalTrials.gov registration: NCT03107988

Genomic Profiling of Childhood Tumor Patient-Derived Xenograft Models to Enable Rational Clinical Trial Design.

Accelerating cures for children with cancer remains an immediate challenge as a result of extensive oncogenic heterogeneity between and within histologies, distinct molecular mechanisms evolving between diagnosis and relapsed disease, and limited therapeutic options. To systematically prioritize and rationally test novel agents in preclinical murine models, researchers within the Pediatric Preclinical Testing Consortium are continuously developing patient-derived xenografts (PDXs)-many of which are refractory to current standard-of-care treatments-from high-risk childhood cancers. Here, we genomically characterize 261 PDX models from 37 unique pediatric cancers; demonstrate faithful recapitulation of histologies and subtypes; and refine our understanding of relapsed disease. In addition, we use expression signatures to classify tumors for TP53 and NF1 pathway inactivation. We anticipate that these data will serve as a resource for pediatric oncology drug development and will guide rational clinical trial design for children with cancer

Genetic influences in different aspects of language development: The etiology of language skills in 4.5 year-old twins

The genetic and environmental etiologies of diverse aspects of language ability and disability, including articulation, phonology, grammar, vocabulary, and verbal memory, were investigated in a U.K. sample of 787 pairs of 4.5-year-old same-sex and opposite-sex twins. Moderate genetic influence was found for all aspects of language in the normal range. A similar pattern was found at the low end of the distribution with the exception of two receptive measures. Environmental influence was mainly due to nonshared factors, unique to the individual, with little influence from shared environment for most measures. Genetic and environmental influences on language ability and disability are quantitatively and qualitatively similar for males and females

Comparing different models of the development of verb inflection in early child Spanish

How children acquire knowledge of verb inflection is a long-standing question in language acquisition research. In the present study, we test the predictions of some current constructivist and generativist accounts of the development of verb inflection by focusing on data from two Spanish-speaking children between the ages of 2;0 and 2;6. The constructivist claim that children's early knowledge of verb inflection is only partially productive is tested by comparing the average number of different inflections per verb in matched samples of child and adult speech. The generativist claim that children's early use of verb inflection is essentially error-free is tested by investigating the rate at which the children made subjectverb agreement errors in different parts of the present tense paradigm. Our results show: 1) that, although even adults ' use of verb inflection in Spanish tends to look somewhat lexically restricted, both children's use of verb inflection was significantly less flexible than that of their caregivers, and 2) that, although the rate at which the two children produced subjectverb agreement errors in their speech was very low, this overall error rate hid a consistent pattern of error in which error rates were substantially higher in low frequency than in high frequency contexts, and substantially higher for low frequency than for high frequency verbs. These results undermine the claim that children's use of verb inflection is fully productive from the earliest observable stages, and are consistent with the constructivist claim that knowledge of verb inflection develops only gradually

Household and market survey on availability of adequately iodized salt in the Volta region, Ghana

This is an Accepted Manuscript of an article published by Taylor & Francis in International Journal of Health Promotion and Education on 27/10/2016, available online: http://www.tandfonline.com/doi/full/10.1080/14635240.2016.1250658Consumption of adequately iodized salt (AIS) ≥15ppm is one of the criteria for measuring progress towards universal salt iodization (USI) and sustainable elimination of iodine deficiency disorders. After series of health promotion activities, this survey was conducted to evaluate the extent to which USI was achieved. Cross-sectional survey was conducted in 1,961 households and 350 markets to estimate the iodine levels of salt consumed or sold. Three degrees of iodization were estimated from fine, coarse and granular texture salt using MBI rapid field test kits. Differences in iodization levels were determined using Bonferroni test in STATA. Determinants for household utilization of AIS were identified using regression analysis and reported as odds ratio (OR). Availability of AIS in households (24.5%) and markets (30.9%) was far below the 90% recommendation. No differences where observed in urban (26.8%) and rural (24.1%) households. Households that used fine-texture salt (OR: 40.13; CI: 30.1-53.4) or stored salt in original packs (OR: 8.02; CI: 6.01-10.70) were more likely to consume AIS. Across districts, highest household availability of AIS was 51.7% while the least was 7.5%. The district with the highest market availability of AIS was 85.7% while the least was 8.3%. Almost 32% of the traders were aware that selling non-iodized salt was unauthorized but out of this, only 12% sold AIS. Public education should emphasis appropriate handling and storage of salt throughout the supply chain. To ensure adequate salt fortification with iodine, improved surveillance of factories and mining sites is recommended

Structure of dislocations in Al and Fe as studied by positron-annihilation spectroscopy

Positron-lifetime-spectra measurements have been performed on single crystals of Al and polycrystals of Fe deformed under the tensile mode at room temperature and 77 K, respectively. It is shown that the positron-trapping component in Al depends on the number of slip systems activated: The positron lifetime is 215, 220, and 240 ps when single-, double-, and multiple-slip planes are activated, respectively. This dependence is well understood if positrons annihilate at dislocation-associated defects (jogs) with different positron-annihilation characteristics revealing different jog structures. In iron, the positron-lifetime spectra associated with dislocations were found to be independent of the annealing temperature between 110 and 360 K. In this temperature range, screw dislocations should transform into nonscrew dislocations, suggesting that the positrons are not sensitive to the different types of dislocations. These results are interpreted on the basis that positrons annihilate at defects associated with the dislocations rather than at the dislocation lines. © 1992 The American Physical Society.Peer Reviewe