The rarity of terrestrial gamma-ray flashes

We report on the first search for Terrestrial Gamma-ray Flashes (TGFs) from altitudes where they are thought to be produced. The Airborne Detector for Energetic Lightning Emissions (ADELE), an array of gamma-ray detectors, was flown near the tops of Florida thunderstorms in August/September 2009. The plane passed within 10 km horizontal distance of 1213 lightning discharges and only once detected a TGF. If these discharges had produced TGFs of the same intensity as those seen from space, every one should have been seen by ADELE. Separate and significant nondetections are established for intracloud lightning, negative cloud-to-ground lightning, and narrow bipolar events. We conclude that TGFs are not a primary triggering mechanism for lightning. We estimate the TGF-to-flash ratio to be on the order of 10^(−2) to 10^(−3) and show that TGF intensities cannot follow the well-known power-law distribution seen in earthquakes and solar flares, due to our limits on the presence of faint events

The Cosmic Background Imager

Design and performance details are given for the Cosmic Background Imager (CBI), an interferometer array that is measuring the power spectrum of fluctuations in the cosmic microwave background radiation (CMBR) for multipoles in the range 400 < l < 3500. The CBI is located at an altitude of 5000 m in the Atacama Desert in northern Chile. It is a planar synthesis array with 13 0.9-m diameter antennas on a 6-m diameter tracking platform. Each antenna has a cooled, low-noise receiver operating in the 26-36 GHz band. Signals are cross-correlated in an analog filterbank correlator with ten 1 GHz bands. This allows spectral index measurements which can be used to distinguish CMBR signals from diffuse galactic foregrounds. A 1.2 kHz 180-deg phase switching scheme is used to reject cross-talk and low-frequency pick-up in the signal processing system. The CBI has a 3-axis mount which allows the tracking platform to be rotated about the optical axis, providing improved (u,v) coverage and a powerful discriminant against false signals generated in the receiving electronics. Rotating the tracking platform also permits polarization measurements when some of the antennas are configured for the orthogonal polarization.Comment: 14 pages. Accepted for publication in PASP. See also http://www.astro.caltech.edu/~tjp/CBI

Critical incident technique: an innovative participatory approach to examine and document racial disparities in breast cancer healthcare services

Disproportionate and persistent inequities in quality of healthcare have been observed among persons of color in the United States. To understand and ultimately eliminate such inequities, several public health institutions have issued calls for innovative methods and approaches that examine determinants from the social, organizational and public policy contexts to inform the design of systems change interventions. The authors, including academic and community research partners in a community-based participatory research (CBPR) study, reflected together on the use and value of the critical incident technique (CIT) for exploring racial disparities in healthcare for women with breast cancer. Academic and community partners used initial large group discussion involving a large partnership of 35 academic and community researchers guided by principles of CBPR, followed by the efforts of a smaller interdisciplinary manuscript team of academic and community researchers to reflect, document summarize and translate this participatory research process, lessons learned and value added from using the CIT with principles of CBPR and Undoing Racism. The finding of this article is a discussion of the process, strengths and challenges of utilizing CIT with CBPR. The participation of community members at all levels of the research process including development, collection of the data and analysis of the data was enhanced by the CIT process. As the field of CBPR continues to mature, innovative processes which combine the expertise of community and academic partners can enhance the success of such partnerships. This report contributes to existing literature by illustrating a unique and participatory research application of CIT with principles of CBPR and Undoing Racism. Findings highlight the collaborative process used to identify and implement this novel method and the adaptability of this technique in the interdisciplinary exploration of system-level changes to understand and address disparities in breast cancer and cancer care

Mass equidistribution of Hilbert modular eigenforms

Let F be a totally real number field, and let f traverse a sequence of non-dihedral holomorphic eigencuspforms on GL(2)/F of weight (k_1,...,k_n), trivial central character and full level. We show that the mass of f equidistributes on the Hilbert modular variety as max(k_1,...,k_n) tends to infinity. Our result answers affirmatively a natural analogue of a conjecture of Rudnick and Sarnak (1994). Our proof generalizes the argument of Holowinsky-Soundararajan (2008) who established the case F = Q. The essential difficulty in doing so is to adapt Holowinsky's bounds for the Weyl periods of the equidistribution problem in terms of manageable shifted convolution sums of Fourier coefficients to the case of a number field with nontrivial unit group.Comment: 40 pages; typos corrected, nearly accepted for

Stoichiometry of a regulatory splicing complex revealed by single-molecule analyses

Splicing is regulated by complex interactions of numerous RNA-binding proteins. The molecular mechanisms involved remain elusive, in large part because of ignorance regarding the numbers of proteins in regulatory complexes. Polypyrimidine tract-binding protein (PTB), which regulates tissue-specific splicing, represses exon 3 of α-tropomyosin through distant pyrimidine-rich tracts in the flanking introns. Current models for repression involve either PTB-mediated looping or the propagation of complexes between tracts. To test these models, we used single-molecule approaches to count the number of bound PTB molecules both by counting the number of bleaching steps of GFP molecules linked to PTB within complexes and by analysing their total emissions. Both approaches showed that five or six PTB molecules assemble. Given the domain structures, this suggests that the molecules occupy primarily multiple overlapping potential sites in the polypyrimidine tracts, excluding propagation models. As an alternative to direct looping, we propose that repression involves a multistep process in which PTB binding forms small local loops, creating a platform for recruitment of other proteins that bring these loops into close proximity

Preliminary analysis of the genetic variability of two natural beds of the Scallop Euvola ziczac (Linnaeus, 1758) in Brazil

Euvola ziczac (formerly Pecten ziczac), a simultaneous hermaphroditic scallop was heavily fished in Brazil between 1972 and 1980. The production peaked in 1980 with 8,800 tons and was followed by the total collapse of the resource. In order to investigate the possible loss of genetic variability of the stock associated to overfishing and self-fertilization, the polymorphism of phosphoglucomutase (PGM) and glucose phosphate isomerase (GPI) was analyzed by electrophoresis of the adductor muscle of scallops from São Francisco (26° 20.583S; 48° 16.507W) and Bom Abrigo (25° 28.735S; 47° 37.621W) beds; the southern and northern extremes of the scallop fishing ground, respectively. Animals from São Francisco showed a strong deficiency of heterozygosity for GPI and PGM. In addition, PGM showed *exclusive alleles for each bed. Such results coupled with other information about the species suggested the following hypothesis: a) the stock was a metapopulation with at least two populations; b) some reproductive isolation might be occurring which might be influenced by conditions of larval transport and by the extremely low densities of scallops; c) presently, the stock seemed to be mostly maintained through self-fertilization; d) São Francisco could constitute a source-area, contributing with larvae and recruits to Bom Abrigo and other areas; e) both beds were suffering a genetic homogenization more evident in São Francisco. Such hypothesis needed to be investigated in order to furnish guidelines for future programs of recovery and management of the resource.info:eu-repo/semantics/publishedVersio

A Holistic Systems Approach to Characterize the Impact of Pre- and Post-natal Oxycodone Exposure on Neurodevelopment and Behavior

Background: Increased risk of oxycodone (oxy) dependency during pregnancy has been associated with altered behaviors and cognitive deficits in exposed offspring. However, a significant knowledge gap remains regarding the effect of in utero and postnatal exposure on neurodevelopment and subsequent behavioral outcomes. Methods: Using a preclinical rodent model that mimics oxy exposure in utero (IUO) and postnatally (PNO), we employed an integrative holistic systems biology approach encompassing proton magnetic resonance spectroscopy (1H-MRS), electrophysiology, RNA-sequencing, and Von Frey pain testing to elucidate molecular and behavioral changes in the exposed offspring during early neurodevelopment as well as adulthood. Results: 1H-MRS studies revealed significant changes in key brain metabolites in the exposed offspring that were corroborated with changes in synaptic currents. Transcriptomic analysis employing RNA-sequencing identified alterations in the expression of pivotal genes associated with synaptic transmission, neurodevelopment, mood disorders, and addiction in the treatment groups. Furthermore, Von Frey analysis revealed lower pain thresholds in both exposed groups. Conclusions: Given the increased use of opiates, understanding the persistent developmental effects of these drugs on children will delineate potential risks associated with opiate use beyond the direct effects in pregnant women

Chemistry of layered d-metal pnictide oxides and their potential as candidates for new superconductors

Layered d-metal pnictide oxides are a unique class of compounds which consists of characteristic d-metal pnictide layers and metal oxide layers. More than 100 of these layered compounds, including the recently discovered Fe-based superconducting pnictide oxides, can be classified into 9 structure types. These structure types and the chemical and physical properties of the characteristic d-metal pnictide layers and metal oxide layers of the layered d-metal pnictide oxides are reviewed and discussed. Furthermore, possible approaches to design new superconductors based on these layered d-metal pnictide oxides are proposed.Comment: 29 pages including 6 tables and 2 figure

Deep Broadband Observations of the Distant Gamma-ray Blazar PKS 1424+240

We present deep VERITAS observations of the blazar PKS 1424+240, along with contemporaneous Fermi Large Area Telescope, Swift X-ray Telescope and Swift UV Optical Telescope data between 2009 February 19 and 2013 June 8. This blazar resides at a redshift of $z\ge0.6035$, displaying a significantly attenuated gamma-ray flux above 100 GeV due to photon absorption via pair-production with the extragalactic background light. We present more than 100 hours of VERITAS observations from three years, a multiwavelength light curve and the contemporaneous spectral energy distributions. The source shows a higher flux of (2.1$\pm0.3$)$\times10^{-7}$ ph m$^{-2}$s$^{-1}$ above 120 GeV in 2009 and 2011 as compared to the flux measured in 2013, corresponding to (1.02$\pm0.08$)$\times10^{-7}$ ph m$^{-2}$s$^{-1}$ above 120 GeV. The measured differential very high energy (VHE; $E\ge100$ GeV) spectral indices are $\Gamma=$3.8$\pm$0.3, 4.3$\pm$0.6 and 4.5$\pm$0.2 in 2009, 2011 and 2013, respectively. No significant spectral change across the observation epochs is detected. We find no evidence for variability at gamma-ray opacities of greater than $\tau=2$, where it is postulated that any variability would be small and occur on longer than year timescales if hadronic cosmic-ray interactions with extragalactic photon fields provide a secondary VHE photon flux. The data cannot rule out such variability due to low statistics.Comment: ApJL accepted March 17, 201

Genome erosion and evidence for an intracellular niche – exploring the biology of mycoplasmas in Atlantic salmon

Mycoplasmas are the smallest autonomously self-replicating life form on the planet. Members of this bacterial genus are known to parasitise a wide array of metazoans including vertebrates. Whilst much research has been significant targeted at parasitic mammalian mycoplasmas, very little is known about their role in other vertebrates. In the current study, we aim to explore the biology of mycoplasmas in Atlantic Salmon, a species of major significance for aquaculture, including cellular niche, genome size structure and gene content. Using fluorescent in-situ hybridisation (FISH), mycoplasmas were targeted in epithelial tissues across the digestive tract (stomach, pyloric caecum and midgut) from different development stages (eggs, parr, subadult) of farmed Atlantic salmon (Salmo salar), and we present evidence for an intracellular niche for some of the microbes visualised. Via shotgun metagenomic sequencing, a nearly complete, albeit small, genome (~0.57 MB) as assembled from a farmed Atlantic salmon subadult. Phylogenetic analysis of the recovered genome revealed taxonomic proximity to other salmon derived mycoplasmas, as well as to the human pathogen Mycoplasma penetrans (~1.36 Mb). We annotated coding sequences and identified riboflavin pathway encoding genes and sugar transporters, the former potentially consistent with micronutrient provisioning in salmonid development. Our study provides insights into mucosal adherence, the cellular niche and gene catalog of Mycoplasma in the gut ecosystem of the Atlantic salmon, suggesting a high dependency of this minimalist bacterium on its host. Further study is required to explore and functional role of Mycoplasma in the nutrition and development of its salmonid host