620 research outputs found
Mobility of thorium ions in liquid xenon
We present a measurement of the Th ion mobility in LXe at 163.0 K and
0.9 bar. The result obtained, 0.2400.011 (stat) 0.011 (syst)
cm/(kV-s), is compared with a popular model of ion transport.Comment: 6.5 pages,
Characterization of the near-Earth Asteroid 2002NY40
In August 2002, the near-Earth asteroid 2002 NY40, made its closest approach
to the Earth. This provided an opportunity to study a near-Earth asteroid with
a variety of instruments. Several of the telescopes at the Maui Space
Surveillance System were trained at the asteroid and collected adaptive optics
images, photometry and spectroscopy. Analysis of the imagery reveals the
asteroid is triangular shaped with significant self-shadowing. The photometry
reveals a 20-hour period and the spectroscopy shows that the asteroid is a
Q-type
From "Infant Hercules" to "Ghost Town":Industrial collapse and social harm on Teesside
This article explicates the harms associated with deindustrialization in Teesside in the North East of England in the context of neoliberalism. Drawing on in-depth qualitative interviews (n = 25), the article explores how ongoing industrial collapse, typified by Sahaviriya Steel Industries’ (SSI) closure in 2015, has generated various harms. First, the article examines industrialism’s socioeconomic security and stability. It then explores the negative impact of SSI’s closure in 2015, including a sense of loss and unemployment. Next, it demonstrates how the absence of economic stability produces harmful outcomes, namely insecurity, mental health problems and bleak visions of the future. The article concludes by casting industrial ruination as an impediment to human flourishing; the normal functioning of capitalism represents a “negative motivation to harm” that prevents the stability and security necessary for individual and collective flourishin
Low Complexity Regularization of Linear Inverse Problems
Inverse problems and regularization theory is a central theme in contemporary
signal processing, where the goal is to reconstruct an unknown signal from
partial indirect, and possibly noisy, measurements of it. A now standard method
for recovering the unknown signal is to solve a convex optimization problem
that enforces some prior knowledge about its structure. This has proved
efficient in many problems routinely encountered in imaging sciences,
statistics and machine learning. This chapter delivers a review of recent
advances in the field where the regularization prior promotes solutions
conforming to some notion of simplicity/low-complexity. These priors encompass
as popular examples sparsity and group sparsity (to capture the compressibility
of natural signals and images), total variation and analysis sparsity (to
promote piecewise regularity), and low-rank (as natural extension of sparsity
to matrix-valued data). Our aim is to provide a unified treatment of all these
regularizations under a single umbrella, namely the theory of partial
smoothness. This framework is very general and accommodates all low-complexity
regularizers just mentioned, as well as many others. Partial smoothness turns
out to be the canonical way to encode low-dimensional models that can be linear
spaces or more general smooth manifolds. This review is intended to serve as a
one stop shop toward the understanding of the theoretical properties of the
so-regularized solutions. It covers a large spectrum including: (i) recovery
guarantees and stability to noise, both in terms of -stability and
model (manifold) identification; (ii) sensitivity analysis to perturbations of
the parameters involved (in particular the observations), with applications to
unbiased risk estimation ; (iii) convergence properties of the forward-backward
proximal splitting scheme, that is particularly well suited to solve the
corresponding large-scale regularized optimization problem
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Bioavailability in soils
The consumption of locally-produced vegetables by humans may be an important exposure pathway for soil contaminants in many urban settings and for agricultural land use. Hence, prediction of metal and metalloid uptake by vegetables from contaminated soils is an important part of the Human Health Risk Assessment procedure. The behaviour of metals (cadmium, chromium, cobalt, copper, mercury, molybdenum, nickel, lead and zinc) and metalloids (arsenic, boron and selenium) in contaminated soils depends to a large extent on the intrinsic charge, valence and speciation of the contaminant ion, and soil properties such as pH, redox status and contents of clay and/or organic matter. However, chemistry and behaviour of the contaminant in soil alone cannot predict soil-to-plant transfer. Root uptake, root selectivity, ion interactions, rhizosphere processes, leaf uptake from the atmosphere, and plant partitioning are important processes that ultimately govern the accumulation ofmetals and metalloids in edible vegetable tissues. Mechanistic models to accurately describe all these processes have not yet been developed, let alone validated under field conditions. Hence, to estimate risks by vegetable consumption, empirical models have been used to correlate concentrations of metals and metalloids in contaminated soils, soil physico-chemical characteristics, and concentrations of elements in vegetable tissues. These models should only be used within the bounds of their calibration, and often need to be re-calibrated or validated using local soil and environmental conditions on a regional or site-specific basis.Mike J. McLaughlin, Erik Smolders, Fien Degryse, and Rene Rietr
“It’s not something I chose you know”: making sense of pedophiles’ sexual interest in children and the impact on their psychosexual identity
Sexual interest in children is one of the most strongly predictive of the known risk factors for sexual reconviction. It is an important aspect of risk assessment to identify the presence of such interest, and an important task for treatment providers to address such a sexual interest where it is present. It has been argued that understanding pedophiles’ deviant sexual interest in children can enhance risk assessment, management, and treatment planning. This research study aims to explore the phenomenology of deviant sexual interest in children, the impact it has on pedophilic offenders’ identities, and their views on the treatability of that interest. The study used semistructured interviews and repertory grids to make sense of participants’ experiences. The results revealed three superordinate themes: “‘living’ with a deviant sexual interest,” “relational sexual self,” and “possible and feared sexual self.” The analysis unpacks these themes and repertory grid analysis is used to explore a subset of participants’ identities in more detail. The results reveal that there needs to be an acceptance from both client and therapist that their sexual interest in children may never go away. Through this acceptance, clients could work on enhancing sexual self-regulation, recognizing their triggers, and so managing their sexual thoughts, feelings, and behavior. Implications for treatment are also discussed
Pseudouridine profiling reveals regulated mRNA pseudouridylation in yeast and human cells
Post-transcriptional modification of RNA nucleosides occurs in all living organisms. Pseudouridine, the most abundant modified nucleoside in non-coding RNAs, enhances the function of transfer RNA and ribosomal RNA by stabilizing the RNA structure. Messenger RNAs were not known to contain pseudouridine, but artificial pseudouridylation dramatically affects mRNA function—it changes the genetic code by facilitating non-canonical base pairing in the ribosome decoding centre. However, without evidence of naturally occurring mRNA pseudouridylation, its physiological relevance was unclear. Here we present a comprehensive analysis of pseudouridylation in Saccharomyces cerevisiae and human RNAs using Pseudo-seq, a genome-wide, single-nucleotide-resolution method for pseudouridine identification. Pseudo-seq accurately identifies known modification sites as well as many novel sites in non-coding RNAs, and reveals hundreds of pseudouridylated sites in mRNAs. Genetic analysis allowed us to assign most of the new modification sites to one of seven conserved pseudouridine synthases, Pus1–4, 6, 7 and 9. Notably, the majority of pseudouridines in mRNA are regulated in response to environmental signals, such as nutrient deprivation in yeast and serum starvation in human cells. These results suggest a mechanism for the rapid and regulated rewiring of the genetic code through inducible mRNA modifications. Our findings reveal unanticipated roles for pseudouridylation and provide a resource for identifying the targets of pseudouridine synthases implicated in human disease.American Cancer Society (Robbie Sue Mudd Kidney Cancer Research Scholar Grant RSG-13-396-01-RMC)National Institutes of Health (U.S.) (GM094303)National Institutes of Health (U.S.) (GM081399)American Cancer Society. New England Division (Ellison Foundation Postdoctoral Fellowship)American Cancer Society (Postdoctoral Fellowship PF-13-319-01-RMC)National Institutes of Health (U.S.) (Pre-doctoral Training Grant T32GM007287
Molecular Evolution of Regulatory Genes in Spruces from Different Species and Continents: Heterogeneous Patterns of Linkage Disequilibrium and Selection but Correlated Recent Demographic Changes
Genes involved in transcription regulation may represent valuable targets in association genetics studies because of their key roles in plant development and potential selection at the molecular level. Selection and demographic signatures at the sequence level were investigated for five regulatory genes belonging to the knox-I family (KN1, KN2, KN3, KN4) and the HD-Zip III family (HB-3) in three Picea species affected by post-glacial recolonization in North America and Europe. To disentangle neutral and selective forces and estimate linkage disequilibrium (LD) on a gene basis, complete or nearly complete gene sequences were analysed. Nucleotide variation within species, haplotype structure, LD, and neutrality tests, in addition to coalescent simulations based on Tajima’s D and Fay and Wu’s H, were estimated. Nucleotide diversity was generally low in all species (average π = 0.002–0.003) and much heterogeneity was seen in LD and selection signatures among genes and species. Most of the genes harboured an excess of both rare and frequent alleles in the three species. Simulations showed that this excess was significantly higher than that expected under neutrality and a bottleneck during the Last Glacial Maximum followed by population expansion at the Pleistocene/Holocene boundary or shortly after best explains the correlated sequence patterns. These results indicate that despite recent large demographic changes in the three boreal species from two continents, species-specific selection signatures could still be detected from the analysis of nearly complete regulatory gene sequences. Such different signatures indicate differential subfunctionalization of gene family members in the three congeneric species
Atypical birdsong and artificial languages provide insights into how communication systems are shaped by learning, use and transmission
In this article, I argue that a comparative approach focusing on the cognitive capacities and behavioral mechanisms that underlie vocal learning in songbirds and humans can provide valuable insights into the evolutionary origins of language. The experimental approaches I discuss use abnormal song and atypical linguistic input to study the processes of individual learning, social interaction, and cultural transmission. Atypical input places increased learning and communicative pressure on learners, so exploring how they respond to this type of input provides a particularly clear picture of the biases and constraints at work during learning and use. Furthermore, simulating the cultural transmission of these unnatural communication systems in the laboratory informs us about how learning and social biases influence the structure of communication systems in the long run. Findings based on these methods suggest fundamental similarities in the basic social–cognitive mechanisms underlying vocal learning in birds and humans, and continuing research promises insights into the uniquely human mechanisms and into how human cognition and social behavior interact, and ultimately impact on the evolution of language
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