1,556 research outputs found
Analysis of resonance multipoles from polarization observables in eta photoproduction
A combined analysis of new eta photoproduction data for total and
differential cross sections, target asymmetry and photon asymmetry is
presented. Using a few reasonable assumptions we perform the first
model-independent analysis of the E0+, E2- and M2- eta photoproduction
multipoles. Making use of the well-known A3/2 helicity amplitude of the
D13(1520) state we extract its branching ratio to the eta-N channel,
Gamma(eta,N)/Gamma = (0.08 +- 0.01)%. At higher energies, we show that the
photon asymmetry is extremely sensitive to small multipoles that are excited by
photons in the helicity 3/2 state. The new GRAAL photon asymmetry data at
higher energy show a clear signal of the F15(1680) excitation which permits
extracting an F15(1680)->eta,N branching ratio of (0.15 +0.35 -0.10)%.Comment: 14 pages of LATEX including 7 postscript figure
Comparison of Bacterial Diversity within the Coral Reef Sponge, Axinella corrugata, and the Encrusting Coral Erythropodium caribaeorum
We compared the Caribbean reef sponge, Axinella corrugata, with the Caribbean reef coral, Erythropodium caribaeorum for differences in their resident microbial communities. This cursory survey of bacterial diversity applied 16S rRNA gene sequences. Over 100 culture-independent sequences were generated from five different Axinella 16S rRNA libraries, and compared with 69 cultured isolates. The cultureindependent 16S rDNA clones displayed a higher diversity of Proteobacteria, including âunculturedâ or âunknownâ representatives from the Deltaproteobacteria. Arcobacterium, and Cyanobacteria were also found. We have also confirmed that Axinella sponges appeared to host specific microbial symbionts, similar to the previously identified clones termed âOSOâ environmental samples. In contrast, seawater samples near Axinella were dominated by Pseudoalteromonas. Adjacent sediment samples yielded clones of Planctomycetacea, Proteobacteria, sulfate-reducing Desulfovibrio spp, and other Deltaproteobacteria. Anaerobe-like 16S rRNA sequences were detected after the oxygen supply to one Axinella sample was deliberately curtailed to assess temporal changes in the microbial community. E. caribaeorum yielded more Betaproteobacteria relative to Axinella 16S libraries, and also included the Gammaproteobacteria genus Spongiobacter. However, Axinella-derived microbes appeared phylogenetically deeper with greater sequence divergences than the coral. Overall this study indicated that marine microbial community diversity can be linked to specific source hosts and habitats
Advanced resistivity model for arbitrary magnetization orientation applied to a series of compressive- to tensile-strained (Ga,Mn)As layers
The longitudinal and transverse resistivities of differently strained
(Ga,Mn)As layers are theoretically and experimentally studied as a function of
the magnetization orientation. The strain in the series of (Ga,Mn)As layers is
gradually varied from compressive to tensile using (In,Ga)As templates with
different In concentrations. Analytical expressions for the resistivities are
derived from a series expansion of the resistivity tensor with respect to the
direction cosines of the magnetization. In order to quantitatively model the
experimental data, terms up to the fourth order have to be included. The
expressions derived are generally valid for any single-crystalline cubic and
tetragonal ferromagnet and apply to arbitrary surface orientations and current
directions. The model phenomenologically incorporates the longitudinal and
transverse anisotropic magnetoresistance as well as the anomalous Hall effect.
The resistivity parameters obtained from a comparison between experiment and
theory are found to systematically vary with the strain in the layer.Comment: 14 pages, 11 figures, submitted to Phys. Rev.
MicroRNA profiling reveals marker of motor neuron disease in ALS models
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder marked by the loss of motor neurons (MNs) in the brain and spinal cord, leading to fatally debilitating weakness. Because this disease predominantly affects MNs, we aimed to characterize the distinct expression profile of that cell type to elucidate underlying disease mechanisms and to identify novel targets that inform on MN health during ALS disease time course. microRNAs (miRNAs) are short, noncoding RNAs that can shape the expression profile of a cell and thus often exhibit cell-type-enriched expression. To determine MN-enriched miRNA expression, we used Cre recombinase-dependent miRNA tagging and affinity purification in mice. By defining thein vivomiRNA expression of MNs, all neurons, astrocytes, and microglia, we then focused on MN-enriched miRNAs via a comparative analysis and found that they may functionally distinguish MNs postnatally from other spinal neurons. Characterizing the levels of the MN-enriched miRNAs in CSF harvested from ALS models of MN disease demonstrated that one miRNA (miR-218) tracked with MN loss and was responsive to an ALS therapy in rodent models. Therefore, we have used cellular expression profiling tools to define the distinct miRNA expression of MNs, which is likely to enrich future studies of MN disease. This approach enabled the development of a novel, drug-responsive marker of MN disease in ALS rodents.SIGNIFICANCE STATEMENTAmyotrophic lateral sclerosis (ALS) is a neurodegenerative disease in which motor neurons (MNs) in the brain and spinal cord are selectively lost. To develop tools to aid in our understanding of the distinct expression profiles of MNs and, ultimately, to monitor MN disease progression, we identified small regulatory microRNAs (miRNAs) that were highly enriched or exclusive in MNs. The signal for one of these MN-enriched miRNAs is detectable in spinal tap biofluid from an ALS rat model, where its levels change as disease progresses, suggesting that it may be a clinically useful marker of disease status. Furthermore, rats treated with ALS therapy have restored expression of this MN RNA marker, making it an MN-specific and drug-responsive marker for ALS rodents.</jats:p
Loss of AP-3 function affects spontaneous and evoked release at hippocampal mossy fiber synapses
Synaptic vesicle (SV) exocytosis mediating neurotransmitter release occurs
spontaneously at low intraterminal calcium concentrations and is stimulated by
a rise in intracellular calcium. Exocytosis is compensated for by the
reformation of vesicles at plasma membrane and endosomes. Although the adaptor
complex AP-3 was proposed to be involved in the formation of SVs from
endosomes, whether its function has an indirect effect on exocytosis remains
unknown. Using mocha mice, which are deficient in functional AP-3, we identify
an AP-3-dependent tetanus neurotoxin-resistant asynchronous release that can be
evoked at hippocampal mossy fiber (MF) synapses. Presynaptic targeting of the
tetanus neurotoxin-resistant vesicle soluble N-ethylmaleimide-sensitive factor
attachment protein receptor (SNARE) tetanus neurotoxin-insensitive
vesicle-associated membrane protein (TI-VAMP) is lost in mocha hippocampal MF
terminals, whereas the localization of synaptobrevin 2 is unaffected. In
addition, quantal release in mocha cultures is more frequent and more sensitive
to sucrose. We conclude that lack of AP-3 results in more constitutive
secretion and loss of an asynchronous evoked release component, suggesting an
important function of AP-3 in regulating SV exocytosis at MF terminals
The role of social identity and self-efficacy in predicting service providersâ use of Stepping Stones Triple P following training
Background: Identifying factors that may contribute to the use of programs following the completion of training by practitioners is of practical and theoretical importance. Aim: This study examined the role of social identity and self-efficacy in contributing to the delivery of an evidence-based parenting program. Methods and Procedures: A sample of 63 multi-disciplinary professionals trained in the Stepping Stones Triple P-Positive Parenting Program, for parents of children with developmental disability, as part of a statewide roll-out were interviewed two years after training. Data on the number of hours of delivery during the 2-year period was analysed along with quantitative data obtained during interviews that assessed professionalsâ self-efficacy and social identity as a Stepping Stones professional. Outcomes and Results: Social identity was associated with the use of SSTP in an independent analysis, but the association was no longer significant when other factors were included in a regression model. Self-efficacy predicted the use of SSTP and was found to be a mediator in the relationship between social identity and use of SSTP. Conclusions and Implications: This first investigation into the role of social identity in the implementation of evidence-based parenting programs showed that social identity could play an important role. The role of self-efficacy in predicting program use was further supported in this study and the mediator function of self-efficacy is explored. The practical and theoretical implications of the role of self-efficacy and social identity in the training of professionals are discussed.</p
The cranial osteology and feeding ecology of the Metriorhynchid Crocodylomorph Genera <i>Dakosaurus</i> and <i>Plesiosuchus</i> from the late Jurassic of Europe
Background: Dakosaurus and Plesiosuchus are characteristic genera of aquatic, large-bodied, macrophagous metriorhynchid crocodylomorphs. Recent studies show that these genera were apex predators in marine ecosystems during the latter part of the Late Jurassic, with robust skulls and strong bite forces optimized for feeding on large prey. Methodology/Principal Findings: Here we present comprehensive osteological descriptions and systematic revisions of the type species of both genera, and in doing so we resurrect the genus Plesiosuchus for the species Dakosaurus manselii. Both species are diagnosed with numerous autapomorphies. Dakosaurus maximus has premaxillary 'lateral plates'; strongly ornamented maxillae; macroziphodont dentition; tightly fitting tooth-to-tooth occlusion; and extensive macrowear on the mesial and distal margins. Plesiosuchus manselii is distinct in having: non-amblygnathous rostrum; long mandibular symphysis; microziphodont teeth; tooth-crown apices that lack spalled surfaces or breaks; and no evidence for occlusal wear facets. Our phylogenetic analysis finds Dakosaurus maximus to be the sister taxon of the South American Dakosaurus andiniensis, and Plesiosuchus manselii in a polytomy at the base of Geosaurini (the subclade of macrophagous metriorhynchids that includes Dakosaurus, Geosaurus and Torvoneustes). Conclusions/Significance: The sympatry of Dakosaurus and Plesiosuchus is curiously similar to North Atlantic killer whales, which have one larger 'type' that lacks tooth-crown breakage being sympatric with a smaller 'type' that has extensive crown breakage. Assuming this morphofunctional complex is indicative of diet, then Plesiosuchus would be a specialist feeding on other marine reptiles while Dakosaurus would be a generalist and possible suction-feeder. This hypothesis is supported by Plesiosuchus manselii having a very large optimum gape (gape at which multiple teeth come into contact with a prey-item), while Dakosaurus maximus possesses craniomandibular characteristics observed in extant suction-feeding odontocetes: shortened tooth-row, amblygnathous rostrum and a very short mandibular symphysis. We hypothesise that trophic specialisation enabled these two large-bodied species to coexist in the same ecosystem.Facultad de Ciencias Naturales y Muse
NOP Receptor Antagonists Decrease Alcohol Drinking in the Dark in C57BL/6J Mice
Background: The nociceptin/orphanin FQ opioid peptide (NOP) receptor and its endogenous ligand N/OFQ have been implicated in the regulation of drug and alcohol use disorders (AUD). In particular, evidence demonstrated that NOP receptor activation blocks reinforcing and motivating effects of alcohol across a range of behavioral measures, including alcohol intake, conditioned place preference, and vulnerability to relapse. Methods: Here, we show the effects of pharmacological activation and inhibition of NOP receptors on binge-like alcohol consumption, as measured by the âdrinking in the darkâ (DID) model in C57BL/6J mice. Results: We found that 2 potent and selective NOP agonists AT-202 (0, 0.3, 1, 3 mg/kg) and AT-312 (0, 0.3, 1 mg/kg) did not affect binge alcohol drinking at doses that do not affect locomotor activity. AT-202 also failed to alter DID behavior when administered to mice previously exposed to chronic alcohol treatment with an alcohol-containing liquid diet. Conversely, treatment with either the high affinity NOP receptor antagonist SB-612111 (0, 3, 10, 30 mg/kg) or the selective antagonist LY2817412 (0, 3, 10, 30 mg/kg) decreased binge drinking. SB-612111 was effective at all doses examined, and LY2817412 was effective at 30 mg/kg. Consistently, NOP receptor knockout mice consumed less alcohol compared to wild type. SB-612111 reduced DID and increased sucrose consumption at doses that do not appear to affect locomotor activity. However, the high dose of SB-612111 (30 mg/kg) reduced alcohol intake but failed to inhibit preference in a 2-bottle choice DID model that can assess moderate alcohol intake. Conclusions: The present results suggest that NOP receptor inhibition rather than activation may represent a valuable approach for treatment of AUD characterized by excessive alcohol consumption such as binge drinking
On the spin-statistics connection in curved spacetimes
The connection between spin and statistics is examined in the context of
locally covariant quantum field theory. A generalization is proposed in which
locally covariant theories are defined as functors from a category of framed
spacetimes to a category of -algebras. This allows for a more operational
description of theories with spin, and for the derivation of a more general
version of the spin-statistics connection in curved spacetimes than previously
available. The proof involves a "rigidity argument" that is also applied in the
standard setting of locally covariant quantum field theory to show how
properties such as Einstein causality can be transferred from Minkowski
spacetime to general curved spacetimes.Comment: 17pp. Contribution to the proceedings of the conference "Quantum
Mathematical Physics" (Regensburg, October 2014
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