Evidence for polarised boron in Co-B and Fe-B alloys

By exploiting the tunability of synchrotron radiation in measurements of spin-resolved photoemission it has proved possible to obtain information on the polarisation of the valence electrons of Co-B and Fe-B amorphous magnetic alloys, Both the spin-integrated and spin-resolved energy distribution curves show a marked dependence on photon energy indicating that the p states of boron hybridise with the d states of the transition metals giving rise to mixed states in the binding energy range 1 to 5 eV, The observed polarisation and spin-resolved densities of states imply that in the above restricted energy range there is a net negative polarisation of the boron states

Recombining your way out of trouble: the genetic architecture of hybrid fitness under environmental stress

Hybridization between species is a fundamental evolutionary force that can both promote and delay adaptation. There is a deficit in our understanding of the genetic basis of hybrid fitness, especially in non-domesticated organisms. We also know little about how hybrid fitness changes as a function of environmental stress. Here, we made genetically variable F2 hybrid populations from two divergent Saccharomyces yeast species, exposed populations to ten toxins, and sequenced the most resilient hybrids on low coverage using ddRADseq. We expected to find strong negative epistasis and heterozygote advantage in the hybrid genomes. We investigated three aspects of hybridness: 1) hybridity, 2) interspecific heterozygosity, and 3) epistasis (positive or negative associations between non-homologous chromosomes). Linear mixed effect models revealed strong genotype-by-environment interactions with many chromosomes and chromosomal interactions showing species-biased content depending on the environment. Against our predictions, we found extensive selection against heterozygosity such that homozygous allelic combinations from the same species were strongly overrepresented in an otherwise hybrid genomic background. We also observed multiple cases of positive epistasis between chromosomes from opposite species, confirmed by epistasis- and selection-free simulations, which is surprising given the large divergence of the parental species (~15% genome-wide). Together, these results suggest that stress-resilient hybrid genomes can be assembled from the best features of both parents, without paying high costs of negative epistasis across large evolutionary distances. Our findings illustrate the importance of measuring genetic trait architecture in an environmental context when determining the evolutionary potential of hybrid populations

Microscopic changes in the spinal extensor musculature in people with chronic spinal pain: a systematic review.

Chronic spinal pain is one the most common musculoskeletal disorders. Previous studies have observed microscopic structural changes in the spinal extensor muscles in people with chronic spinal pain. This systematic review synthesizes and analyses all the existing evidence of muscle microscopic changes in people with chronic spinal pain. To assess the microscopy of spinal extensor muscles including the fiber type composition, the area occupied by fiber types, fiber size/cross sectional area (CSA) and narrow diameter (ND) in people with and without chronic spinal pain. Further, to compare these outcome measures across different regions of the spine in people with chronic neck, thoracic and low back pain. Systematic review with meta-analysis METHODS: MEDLINE (Ovid Interface), Embase, PubMed, CINAHL Plus and Web of Science were searched from inception to October 2020. Key journals, conference proceedings, grey literature and hand searching of reference lists from eligible studies were also searched. Two independent reviewers were involved in the selection process. Only studies examining the muscle microscopy of the spinal extensor muscles (erector spinae (ES) and/or multifidus (MF)) between people with and without chronic spinal pain were selected. The risk of bias from the studies was assessed using modified Newcastle Ottawa Scale and the level of evidence was established using the GRADE approach. Data were synthesized based on homogeneity on the methodology and outcome measures of the studies for ES and MF muscles and only four studies were eligible for analysis. All the five studies included were related to chronic low back pain (CLBP). Meta-analysis (inverse variance method for random effect to calculate mean difference and 95% CI) was performed for the ES fiber type composition by numbers for both type I and type II fibers (I =43% and 0% respectively indicating homogeneity of studies) and showed no difference between the people with and without CLBP with an overall effect estimate Z= 1.49 (p=0.14) and Z=1.06 (p=0.29) respectively. Meta-analysis was performed for ES fiber CSA for both type I and type II fibers (I =0 for both) and showed no difference between people with and without CLBP with an overall effect estimate Z= 0.08 (p=0.43) and Z=0.75 (p=0.45) respectively. Analysis was not performed for ES area occupied by fiber types and ND due to heterogeneity of studies and lack of evidence respectively. Similarly, meta-analysis was not performed for MF fiber type composition by numbers due to heterogeneity of studies. MF analysis for area occupied by fiber type, fiber CSA and ND did not yield sufficient evidence. For the ES muscle, there was no difference in fiber type composition and fiber CSA between people with and without CLBP and no conclusions could be drawn for ND for the ES. For the MF, no conclusions could be drawn for any of the muscle microscopy outcome measures. Overall, the quality of evidence is very low and there is very low evidence that there are no differences in microscopic muscle features between people with and without CLBP. [Abstract copyright: Copyright © 2022. Published by Elsevier Inc.

Ultrathin epitaxial Fe films in vicinal GaAs(001): A study by spin-resolved photoelectron spectroscopy

Thin epitaxial Fe films have been grown on vicinal GaAs(001) substrates and their remanent magnetic properties and the degree of substrate atom diffusion investigated using synchrotron-based photoelectron spectroscopy. The vicinal Fe films, though exhibiting greater As diffusion than their singular homologues, displayed better film quality both from the structural and the magnetic points of view. The spin-resolved valence spectra of the vicinal films resemble those for crystalline bulk Fe at lower film thicknesses than for singular films

Modelling and testing the x-ray performance of CCD and CMOS APS detectors using numerical finite element simulations

Pixellated monolithic silicon detectors operated in a photon-counting regime are useful in spectroscopic imaging applications. Since a high energy incident photon may produce many excess free carriers upon absorption, both energy and spatial information can be recovered by resolving each interaction event. The performance of these devices in terms of both the energy and spatial resolution is in large part determined by the amount of diffusion which occurs during the collection of the charge cloud by the pixels. Past efforts to predict the X-ray performance of imaging sensors have used either analytical solutions to the diffusion equation or simplified monte carlo electron transport models. These methods are computationally attractive and highly useful but may be complemented using more physically detailed models based on TCAD simulations of the devices. Here we present initial results from a model which employs a full transient numerical solution of the classical semiconductor equations to model charge collection in device pixels under stimulation from initially Gaussian photogenerated charge clouds, using commercial TCAD software. Realistic device geometries and doping are included. By mapping the pixel response to different initial interaction positions and charge cloud sizes, the charge splitting behaviour of the model sensor under various illuminations and operating conditions is investigated. Experimental validation of the model is presented from an e2v CCD30-11 device under varying substrate bias, illuminated using an Fe-55 source

Results from EDGES High-Band: II. Constraints on Parameters of Early Galaxies

We use the sky-average spectrum measured by EDGES High-Band ($90-190$ MHz) to constrain parameters of early galaxies independent of the absorption feature at $78$~MHz reported by Bowman et al. (2018). These parameters represent traditional models of cosmic dawn and the epoch of reionization produced with the 21cmFAST simulation code (Mesinger & Furlanetto 2007, Mesinger et al. 2011). The parameters considered are: (1) the UV ionizing efficiency ($\zeta$), (2) minimum halo virial temperature hosting efficient star-forming galaxies ($T^{\rm min}_{\rm vir}$), (3) integrated soft-band X-ray luminosity ($L_{\rm X\,<\,2\,keV}/{\rm SFR}$), and (4) minimum X-ray energy escaping the first galaxies ($E_{0}$), corresponding to a typical H${\rm \scriptstyle I}$ column density for attenuation through the interstellar medium. The High-Band spectrum disfavors high values of $T^{\rm min}_{\rm vir}$ and $\zeta$, which correspond to signals with late absorption troughs and sharp reionization transitions. It also disfavors intermediate values of $L_{\rm X\,<\,2\,keV}/{\rm SFR}$, which produce relatively deep and narrow troughs within the band. Specifically, we rule out $39.4<\log_{10}\left(L_{\rm X\,<\,2\,keV}/{\rm SFR}\right)<39.8$ ($95\%$ C.L.). We then combine the EDGES High-Band data with constraints on the electron scattering optical depth from Planck and the hydrogen neutral fraction from high-$z$ quasars. This produces a lower degeneracy between $\zeta$ and $T^{\rm min}_{\rm vir}$ than that reported in Greig & Mesinger (2017a) using the Planck and quasar constraints alone. Our main result in this combined analysis is the estimate $4.5$~$\leq \log_{10}\left(T^{\rm min}_{\rm vir}/\rm K\right)\leq$~$5.7$ ($95\%$ C.L.). We leave for future work the evaluation of $21$~cm models using simultaneously data from EDGES Low- and High-Band.Comment: Accepted in Ap

Serum Concentrations of Myostatin and Myostatin-Interacting Proteins do not differ between young and Scarcopenic elderly men

Peer reviewedPostprin

Large Magellanic Cloud Planetary Nebula Morphology: Probing Stellar Populations and Evolution

Planetary Nebulae (PNe) in the Large Magellanic Cloud (LMC) offer the unique opportunity to study both the Population and evolution of low- and intermediate-mass stars, by means of the morphological type of the nebula. Using observations from our LMC PN morphological survey, and including images available in the HST Data Archive, and published chemical abundances, we find that asymmetry in PNe is strongly correlated with a younger stellar Population, as indicated by the abundance of elements that are unaltered by stellar evolution (Ne, Ar, S). While similar results have been obtained for Galactic PNe, this is the first demonstration of the relationship for extra-galactic PNe. We also examine the relation between morphology and abundance of the products of stellar evolution. We found that asymmetric PNe have higher nitrogen and lower carbon abundances than symmetric PNe. Our two main results are broadly consistent with the predictions of stellar evolution if the progenitors of asymmetric PNe have on average larger masses than the progenitors of symmetric PNe. The results bear on the question of formation mechanisms for asymmetric PNe, specifically, that the genesis of PNe structure should relate strongly to the Population type, and by inference the mass, of the progenitor star, and less strongly on whether the central star is a member of a close binary system.Comment: The Astrophysical Journal Letters, in press 4 figure

Hot-Fire Thruster Testing Approach at University Level

Technological advancements in chemical propulsion systems leading to increased interest and new applications for small satellites in recent years has created a need for additional testing resources and targeted workforce development. Generally, chemical propulsion testing requires interactions with hazardous materials and environments, which presents significant challenges in a university setting. The Center for Aerospace Exploration and Technology Research (cSETR) at the University of Texas at El Paso (UTEP) has developed a sustainable hot-fire testing program for chemical thrusters that is operated by undergraduate and graduate students. The program is managed analogous to testing programs in professional settings to enable reliable test results, ensure safety of all participants, and provide appropriate training to student engineers. The day-to-day activities of the test program are managed entirely by the student team. A flow-down mentoring approach is used where graduate students with years of experience in the lab train new students joining the program. Tests are planned and executed using standard industry practices, including approved testing procedures, assigned participant roles, and test readiness reviews. The use of a standardized and systematic approach enhances the repeatability and validity of each test. Safety management is achieved using readily-available, low cost resources to maintain operation within a standard University budget. This program is presented as a working example for other University groups looking to establish or improve in-house chemical testing methods to enable expanded hot-fire chemical propulsion testing capabilities and workforce development

Repurposing Immunomodulatory Imide Drugs (IMiDs) in Neuropsychiatric and Neurodegenerative Disorders

Neuroinflammation represents a common trait in the pathology and progression of the major psychiatric and neurodegenerative disorders. Neuropsychiatric disorders have emerged as a global crisis, affecting 1 in 4 people, while neurological disorders are the second leading cause of death in the elderly population worldwide (WHO, 2001; GBD 2016 Neurology Collaborators, 2019). However, there remains an immense deficit in availability of effective drug treatments for most neurological disorders. In fact, for disorders such as depression, placebos and behavioral therapies have equal effectiveness as antidepressants. For neurodegenerative diseases such as Parkinson’s disease and Alzheimer’s disease, drugs that can prevent, slow, or cure the disease have yet to be found. Several non-traditional avenues of drug target identification have emerged with ongoing neurological disease research to meet the need for novel and efficacious treatments. Of these novel avenues is that of neuroinflammation, which has been found to be involved in the progression and pathology of many of the leading neurological disorders. Neuroinflammation is characterized by glial inflammatory factors in certain stages of neurological disorders. Although the meta-analyses have provided evidence of genetic/proteomic upregulation of inflammatory factors in certain stages of neurological disorders. Although the mechanisms underpinning the connections between neuroinflammation and neurological disorders are unclear, and meta-analysis results have shown high sensitivity to factors such as disorder severity and sample type, there is significant evidence of neuroinflammation associations across neurological disorders. In this review, we summarize the role of neuroinflammation in psychiatric disorders such as major depressive disorder, generalized anxiety disorder, post-traumatic stress disorder, and bipolar disorder, as well as in neurodegenerative disorders, such as Parkinson’s disease and Alzheimer’s disease, and introduce current research on the potential of immunomodulatory imide drugs (IMiDs) as a new treatment strategy for these disorders