4,804 research outputs found
The Distribution and Paleoecological Interpretation of Cornulites in the Waynesville Formation (Upper Ordovician) of Southwestern Ohio
Author Institution: Department of Geology, Wittenberg University, Springfield, Ohio and Department of Earth and Planetary Sciences, University of Pittsburgh, Pittsburgh, PennsylvaniaSeventeen species of marine invertebrates collected from the Upper Ordovician Waynesville Formation of southwestern Ohio were found encrusted by Cornulites, a presumed tubicolous annelid worm. Encrustation was interpreted as symbiotic in cases where the cornulitid tubes exhibited preferred orientation upon the exoskeleton of the host. This situation may reflect cornulitid utilization of feeding currents generated or employed by the host species. Symbiotic attachments of Cornulites were encountered most commonly on several species of brachiopods, but were also observed on a pelecypod, a monoplacophoran, two species of bryozoa, and questionably on a gastropod and nautiloid.
Post-mortem encrustation of a host by Cornulites was inferred either from random orientation of the cornulitid tubes or from attachment in a manner or position incompatible with the functional morphology of the host species. Cornulites was found in post-mortem association with brachiopods, bryozoans, and a trilobite. In this situation the host species presumably provided, after death, a suitably hard substrate for cornulitid larval attachment.
Symmetrically positioned cornulitid clusters on a specimen of Cyrtolites sp. cf. C. ornatus Conrad supports the accepted, but unproven, interpretation of bilaterally developed mantle-cavity organs in cyclomyan monoplacophorans
Validating gravitational-wave detections: The Advanced LIGO hardware injection system
Hardware injections are simulated gravitational-wave signals added to the Laser Interferometer Gravitational-wave Observatory (LIGO). The detectors’ test masses are physically displaced by an actuator in order to simulate the effects of a gravitational wave. The simulated signal initiates a control-system response which mimics that of a true gravitational wave. This provides an end-to-end test of LIGO’s ability to observe gravitational waves. The gravitational-wave analyses used to detect and characterize signals are exercised with hardware injections. By looking for discrepancies between the injected and recovered signals, we are able to characterize the performance of analyses and the coupling of instrumental subsystems to the detectors’ output channels. This paper describes the hardware injection system and the recovery of injected signals representing binary black hole mergers, a stochastic gravitational wave background, spinning neutron stars, and sine-Gaussians
Impact of Illness Management and Recovery Programs on Hospital and Emergency Room Use by Medicaid Enrollees
Objective—Illness management and recovery is a structured program that helps consumers with severe mental illness learn effective ways to manage illness and pursue recovery goals. This study
examined the impact of the program on health service utilization.
Methods—This was a retrospective cohort study of five assertive community treatment (ACT) teams in Indiana that implemented illness management and recovery. With Medicaid claims data
from July 1, 2003, to June 30, 2008, panel data were created with person-months as the level of analysis, resulting in 14,261 observations, for a total of 498 unique individuals. Zero-inflated negative binomial regression models were used to predict hospitalization days and emergency room visits, including covariates of demographic characteristics, employment status, psychiatric diagnosis, and concurrent substance use disorder. The main predictor variables of interest were
receipt of illness management and recovery services, dropout from the program, and program graduation status.
Results—Consumers who received some illness management and recovery services had fewer hospitalization days than those receiving only ACT. Graduates had fewer emergency room visits than did ACT-only consumers.
Conclusions—This is the first study to examine the impact of illness management and recovery on service utilization. Controlling for a number of background variables, the study showed that
illness management and recovery programs were associated with reduced inpatient hospitalization and emergency room use over and above ACT
Is there evidence of selection in the dopamine receptor D4 gene in Australian invasive starling populations?
Although population genetic theory is largely based on the premise that loci under study are selectively neutral, it has been acknowledged that the study of DNA sequence data under the influence of selection can be useful. In some circumstances, these loci show increased population differentiation and gene diversity. Highly polymorphic loci may be especially useful when studying populations having low levels of diversity overall, such as is often the case with threatened or newly established invasive populations. Using common starlings Sturnus vulgaris sampled from invasive Australian populations, we investigated sequence data of the dopamine receptor D4 gene (DRD4), a locus suspected to be under selection for novelty-seeking behaviour in a range of taxa including humans and passerine birds. We hypothesised that such behaviour may be advantageous when species encounter novel environments, such as during invasion. In addition to analyses to detect the presence of selection, we also estimated population differentiation and gene diversity using DRD4 data and compared these estimates to those from microsatellite and mitochondrial DNA sequence data, using the same individuals. We found little evidence for selection on DRD4 in starlings. However, we did find elevated levels of within-population gene diversity when compared to microsatellites and mitochondrial DNA sequence, as well as a greater degree of population differentiation. We suggest that sequence data from putatively nonneutral loci are a useful addition to studies of invasive populations, where low genetic variability is expected
Steady Hall Magnetohydrodynamics Near a X-type Magnetic Neutral Line
Hall magnetohydrodynamics (MHD) properties near a two-dimensional (2D) X-type
magnetic neutral line in the steady state are considered via heuristic and
rigorous developments. Upon considering the steady-state as the asymptotic
limit of the corresponding \textit{time-dependent} problem and using a rigorous
development, Hall effects are shown to be able to sustain the hyperbolicity of
the magnetic field (and hence a more open X-point configuration) near the
neutral line in the steady state. The heuristic development misses this subtle
connection of the steady state with the corresponding \textit{time-dependent}
problem and predicts only an elongated current-sheet configuration (as in
resistive MHD). However, the heuristic development turns out to be useful in
providing insight into the lack of dependence of the reconnection rate on the
mechanism breaking the frozen-in condition of the magnetic field lines. The
latter result can be understood in terms of the ability of the ions and
electrons to transport equal amounts of magnetic flux per unit time out of the
reconnection region.Comment: 1-10 page
Surface Superconductivity in Niobium for Superconducting RF Cavities
A systematic study is presented on the superconductivity (sc) parameters of
the ultrapure niobium used for the fabrication of the nine-cell 1.3 GHz
cavities for the linear collider project TESLA. Cylindrical Nb samples have
been subjected to the same surface treatments that are applied to the TESLA
cavities: buffered chemical polishing (BCP), electrolytic polishing (EP),
low-temperature bakeout (LTB). The magnetization curves and the complex
magnetic susceptibility have been measured over a wide range of temperatures
and dc magnetic fields, and also for di erent frequencies of the applied ac
magnetic field. The bulk superconductivity parameters such as the critical
temperature Tc = 9.26 K and the upper critical field Bc2(0) = 410 mT are found
to be in good agreement with previous data. Evidence for surface
superconductivity at fields above Bc2 is found in all samples. The critical
surface field exceeds the Ginzburg-Landau field Bc3 = 1.695Bc2 by about 10% in
BCP-treated samples and increases even further if EP or LTB are applied. From
the field dependence of the susceptibility and a power-law analysis of the
complex ac conductivity and resistivity the existence of two different phases
of surface superconductivity can be established which resemble the Meissner and
Abrikosov phases in the bulk: (1) coherent surface superconductivity, allowing
sc shielding currents flowing around the entire cylindrical sample, for
external fields B in the range between Bc2 and Bcohc3, and (2) incoherent
surface superconductivity with disconnected sc domains between Bcohc3 and Bc3.
The coherent critical surface field separating the two phases is found to be
Bcoh c3 = 0.81Bc3 for all samples. The exponents in the power law analysis are
different for BCP and EP samples, pointing to different surface topologies.Comment: 15 pages, 21 figures, DESY-Report 2004-02
The deletion of the ORF1 and ORF71 genes reduces virulence of the neuropathogenic EHV-1 strain Ab4 without compromising host immunity in horses
The equine herpesvirus type 1 (EHV-1) ORF1 and ORF71 genes have immune modulatory effects in vitro. Experimental infection of horses using virus mutants with multiple deletions including ORF1 and ORF71 showed promise as vaccine candidates against EHV-1. Here, the combined effects of ORF1 and ORF71 deletions from the neuropathogenic EHV-1 strain Ab4 on clinical disease and host immune response were further explored. Three groups of EHV-1 naïve horses were experimentally infected with the ORF1/71 gene deletion mutant (Ab4ΔORF1/71), the parent Ab4 strain, or remained uninfected. In comparison to Ab4, horses infected with Ab4ΔORF1/71 did not show the initial high fever peak characteristic of EHV-1 infection. Ab4ΔORF1/71 infection had reduced nasal shedding (1/5 vs. 5/5) and, simultaneously, decreased intranasal interferon (IFN)-α, interleukin (IL)-10 and soluble CD14 secretion. However, Ab4 and Ab4ΔORF1/71 infection resulted in comparable viremia, suggesting these genes do not regulate the infection of the mononuclear cells and subsequent viremia. Intranasal and serum anti-EHV-1 antibodies to Ab4ΔORF1/71 developed slightly slower than those to Ab4. However, beyond day 12 post infection (d12pi) serum antibodies in both virus-infected groups were similar and remained increased until the end of the study (d114pi). EHV-1 immunoglobulin (Ig) G isotype responses were dominated by short-lasting IgG1 and long-lasting IgG4/7 antibodies. The IgG4/7 response closely resembled the total EHV-1 specific antibody response. Ex vivo re-stimulation of PBMC with Ab4 resulted in IFN-γ and IL-10 secretion by cells from both infected groups within two weeks pi. Flow cytometric analysis showed that IFN-γ producing EHV-1-specific T-cells were mainly CD8+/IFN-γ+ and detectable from d32pi on. Peripheral blood IFN-γ+ T-cell percentages were similar in both infected groups, albeit at low frequency (~0.1%). In summary, the Ab4ΔORF1/71 gene deletion mutant is less virulent but induced antibody responses and cellular immunity similar to the parent Ab4 strain
Integrating Assertive Community Treatment and Illness Management and Recovery for Consumers with Severe Mental Illness
This study examined the integration of two evidence-based practices for adults with severe mental illness: Assertive community treatment (ACT) and illness management and recovery (IMR) with peer specialists as IMR practitioners. Two of four ACT teams were randomly assigned to implement IMR. Over 2 years, the ACT–IMR teams achieved moderate fidelity to the IMR model, but low penetration rates: 47 (25.7%) consumers participated in any IMR sessions and 7 (3.8%) completed the program during the study period. Overall, there were no differences in consumer outcomes at the ACT team level; however, consumers exposed to IMR showed reduced hospital use over time
Expected Shannon entropy and Shannon differentiation between subpopulations for neutral genes under the finite island model
<div><p>Shannon entropy <i>H</i> and related measures are increasingly used in molecular ecology and population genetics because (1) unlike measures based on heterozygosity or allele number, these measures weigh alleles in proportion to their population fraction, thus capturing a previously-ignored aspect of allele frequency distributions that may be important in many applications; (2) these measures connect directly to the rich predictive mathematics of information theory; (3) Shannon entropy is completely additive and has an explicitly hierarchical nature; and (4) Shannon entropy-based differentiation measures obey strong monotonicity properties that heterozygosity-based measures lack. We derive simple new expressions for the expected values of the Shannon entropy of the equilibrium allele distribution at a neutral locus in a single isolated population under two models of mutation: the infinite allele model and the stepwise mutation model. Surprisingly, this complex stochastic system for each model has an entropy expressable as a simple combination of well-known mathematical functions. Moreover, entropy- and heterozygosity-based measures for each model are linked by simple relationships that are shown by simulations to be approximately valid even far from equilibrium. We also identify a bridge between the two models of mutation. We apply our approach to subdivided populations which follow the finite island model, obtaining the Shannon entropy of the equilibrium allele distributions of the subpopulations and of the total population. We also derive the expected mutual information and normalized mutual information (“Shannon differentiation”) between subpopulations at equilibrium, and identify the model parameters that determine them. We apply our measures to data from the common starling (<i>Sturnus vulgaris</i>) in Australia. Our measures provide a test for neutrality that is robust to violations of equilibrium assumptions, as verified on real world data from starlings.</p></div
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