Differing results obtained in the doping of semiconductors by energetic ions

Conflicting results have been reported on the doping of semiconductors by energetic ions. The purpose of this communication is to call attention to certain experimental parameters which are important in resolving these discrepancies

Dynamic facilitation explains democratic particle motion of metabasin transitions

Transitions between metabasins in supercooled liquids seem to occur through rapid "democratic" collective particle rearrangements. Here we show that this apparent homogeneous particle motion is a direct consequence of dynamic facilitation. We do so by studying metabasin transitions in facilitated spin models and constrained lattice gases. We find that metabasin transitions occur through a sequence of locally facilitated events taking place over a relatively short time frame. When observed on small enough spatial windows these events appear sudden and homogeneous. Our results indicate that metabasin transitions are essentially "non-democratic" in origin and yet another manifestation of dynamical heterogeneity in glass formers.Comment: 6 pages, 6 figure

Avalanches and Dynamical Correlations in supercooled liquids

We identify the pattern of microscopic dynamical relaxation for a two dimensional glass forming liquid. On short timescales, bursts of irreversible particle motion, called cage jumps, aggregate into clusters. On larger time scales, clusters aggregate both spatially and temporally into avalanches. This propagation of mobility, or dynamic facilitation, takes place along the soft regions of the systems, which have been identified by computing isoconfigurational Debye-Waller maps. Our results characterize the way in which dynamical heterogeneity evolves in moderately supercooled liquids and reveal that it is astonishingly similar to the one found for dense glassy granular media.Comment: 4 pages, 3 figure

How to be an attractive male: floral dimorphism and attractiveness to pollinators in a dioecious plant

BACKGROUND: Sexual selection theory predicts that males are limited in their reproductive success by access to mates, whereas females are more limited by resources. In animal-pollinated plants, attraction of pollinators and successful pollination is crucial for reproductive success. In dioecious plant species, males should thus be selected to increase their attractiveness to pollinators by investing more than females in floral traits that enhance pollinator visitation. We tested the prediction of higher attractiveness of male flowers in the dioecious, moth-pollinated herb Silene latifolia, by investigating floral signals (floral display and fragrance) and conducting behavioral experiments with the pollinator-moth, Hadena bicruris. RESULTS: As found in previous studies, male plants produced more but smaller flowers. Male flowers, however, emitted significantly larger amounts of scent than female flowers, especially of the pollinator-attracting compounds. In behavioral tests we showed that naïve pollinator-moths preferred male over female flowers, but this preference was only significant for male moths. CONCLUSION: Our data suggest the evolution of dimorphic floral signals is shaped by sexual selection and pollinator preferences, causing sexual conflict in both plants and pollinators

Selection and immunomagnetic purging of peripheral blood CD34+ cells for autologous transplantation in B-cell non-Hodgkin's lymphomas

Background: Clonogenic tumor cells in the hematopoietic progenitor cell harvest may contribute to relapse after high dose therapy for B-cell malignancies. Purging of the HPC harvest requires large amounts of anti-B-cell antibodies, whereas CD34-selection enriches self renewing HPC's but malignant cells are still detectable in many CD34+ fractions. Patients and methods: We examined the feasability and safety of a CD34-selection followed by purging with anti-B-cell antibodies in 11 patients with B-cell non-Hodgkin's lymphomas undergoing high-dose therapy with cyclophospha-mide, BCNU and etoposide with retransfusion of autologous HPC's. Results: A mean number of 340 × 108 mononuclear cells was used for CD34-selection and immunomagnetic purging. CD34+ cells were enriched from a mean of 1.7% (range 0.2%-4.5%) to a mean of 68% (range 49%-87%) with a mean recovery of 27% (range 15%-43%). The mean number of retransfused CD34+ cells was 1.2× 106/kg (range 0.6-2.2 ×106/kg) body weight with a median of 11 days (range 10-13 days) to neutrophil recovery of 0.5×109/1 and 17 days (range 13-25 days) to platelet recovery of 50 × 109/1. Mean number of intravenous antibiotics and inpatient days were 8 (range 0-14) and 22 (range 19-26) respectively. Major toxicity consisted in four septicemias. Conclusions: CD34-selected and purged HPC's are safe and mediate rapid hematological recovery after high dose therapy for B-cell non-Hodgkin's lymphoma

Antibiotic consumption in nursing homes of the Canton of Vaud: trends over the years 2009 - 2014

Background & Objectives: Excessive use of antibiotics in nursing homes was reported in several studies1-3. Surveillance of their use in nursing homes is essential to plan interventions fostering an appropriate use and to measure the impact of these interventions. The aims of the study were to describe the antibiotic consumption in nursing homes of the Canton of Vaud and to examine whether the antibiotic consumption was correlated to the urinary catheter use and to methicillin-resistant Staphylococcus aureus (MRSA) colonization. Methods: Data on the use of systemic antibiotics (class J01 of WHO Anatomical Therapeutic Chemical (ATC) system, 2015) were collected from the community pharmacies' annual invoice data including 13 nursing homes in 2009. The number of nursing homes in the database increased to 67 in 2014, representing 46% of all nursing homes of the Canton of Vaud and 54% of the available beds. Aggregated data were converted into defined daily doses (DDD) and antibiotic consumption expressed in number of defined daily doses per 1000 beds and per day (DDD/1000B/D). Proportion of urinary catheter use and MRSA colonization data were provided through a point prevalence study. Results: The total consumption of systemic antibiotics was 52.2 DDD/1000B/D in 2009 and 48.3 in 2014. Beta-lactam antibacterials other than penicillins, macrolides and other antibacterials (including nitrofurantoin) consumption increased resp. by 80%, 45% and 187% between 2009 and 2014, while the use of sulfonamides and trimethoprim decreased by 41%. Penicillin and quinolone use remained relatively stable between 2009 and 2014. Amoxicillin and clavulanic acid (oral) was the most common antibiotic prescribed (31% of the total use), followed by ciprofloxacin (oral) (20%) and nitrofurantoin (10%). Among nursing homes, we reported a large variation in antibiotic consumption from 6.8 to 164.6 DDD/1000B/D in 2014. No correlation was found between global antibiotic consumption and urinary catheter use and between quinolone consumption and proportion of MRSA in 2010 and 2011 (p>0.05). Discussion & Conclusions: This study is the first that analyzes longitudinal data of antibiotic consumption in nursing homes of the Canton of Vaud. The findings suggest that a large variation in antibiotic consumption exists among nursing homes. Thus, antibiotic stewardship programs should be implemented to promote a more accurate use

Further improvements to linear mixed models for genome-wide association studies

We examine improvements to the linear mixed model (LMM) that better correct for population structure and family relatedness in genome-wide association studies (GWAS). LMMs rely on the estimation of a genetic similarity matrix (GSM), which encodes the pairwise similarity between every two individuals in a cohort. These similarities are estimated from single nucleotide polymorphisms (SNPs) or other genetic variants. Traditionally, all available SNPs are used to estimate the GSM. In empirical studies across a wide range of synthetic and real data, we find that modifications to this approach improve GWAS performance as measured by type I error control and power. Specifically, when only population structure is present, a GSM constructed from SNPs that well predict the phenotype in combination with principal components as covariates controls type I error and yields more power than the traditional LMM. In any setting, with or without population structure or family relatedness, a GSM consisting of a mixture of two component GSMs, one constructed from all SNPs and another constructed from SNPs that well predict the phenotype again controls type I error and yields more power than the traditional LMM. Software implementing these improvements and the experimental comparisons are available at http://microsoft.com/science

Evaluation of range of motion restriction within the hip joint

In Total Hip Arthroplasty, determining the impingement free range of motion requirement is a complex task. This is because in the native hip, motion is restricted by both impingement as well as soft tissue restraint. The aim of this study is to determine a range of motion benchmark which can identify motions which are at risk from impingement and those which are constrained due to soft tissue. Two experimental methodologies were used to determine motions which were limited by impingement and those motions which were limited by both impingement and soft tissue restraint. By comparing these two experimental results, motions which were limited by impingement were able to be separated from those motions which were limited by soft tissue restraint. The results show motions in extension as well as flexion combined with adduction are limited by soft tissue restraint. Motions in flexion, flexion combined with abduction and adduction are at risk from osseous impingement. Consequently, these motions represent where the maximum likely damage will occur in femoroacetabular impingement or at most risk of prosthetic impingement in Total Hip Arthroplasty