1,325 research outputs found
End User Query Performance: The Interaction of User Characteristics and Information Request Ambiguity
This paper investigates the effects of personality characteristics on individualsâ abilities to resolve ambiguity in an information retrieval environment. In particular, this research examines the effects on query performance of the interaction of personality characteristics (as measured using the NEO PI-R) with information requests that contained extraneous, syntactic, or both extraneous and syntactic ambiguities. The results indicate that ambiguity affected performance. The results also show that various personality dimensions significantly affect end-usersâ abilities to compose accurate queries. Neuroticism, agreeableness, openness to experience, and conscientiousness affected the number of errors made in the query formulations. Conscientiousness affected the length of time taken to compose the queries and neuroticism affected the confidence end users had in the accuracy of their queries. In addition, the results indicated that, while the personality dimensions affected performance, there was no interaction between the personality dimensions and ambiguity
Experimental Inoculation of Coyotes with \u3ci\u3eMycobacterium bovis\u3c/i\u3e Susceptibility and Shedding
Several wildlife species have tested positive for bovine tuberculosis in Michigan and may potentially transmit the disease to other animals. Coyotes have the highest known prevalence in the endemic area and thus, our objective was to investigate the shedding of Mycobacterium bovis by coyotes. Four coyotes were orally inoculated with 1 ml of 1 x 105 CFU/ml of M. bovis. Oral and nasal swabs, and feces were collected regularly and tested by culture. Fecal samples were also tested by exposing guinea pigs to the coyotes\u27 feces. All animals were necropsied to determine if infection occurred. All swabs, feces and tissues were negative on culture. The dosage of M. bovis given to these coyotes was considered biologically relevant, but was insufficient for causing infection. Due to the lack of infection, we still do not know the risk coyotes pose for shedding M. bovis
The soil and plant biogeochemistry sampling design for The National Ecological Observatory Network
Human impacts on biogeochemical cycles are evident around the world, from changes to forest structure and function due to atmospheric deposition, to eutrophication of surface waters from agricultural effluent, and increasing concentrations of carbon dioxide (CO2) in the atmosphere. The National Ecological Observatory Network (NEON) will contribute to understanding human effects on biogeochemical cycles from local to continental scales. The broad NEON biogeochemistry measurement design focuses on measuring atmospheric deposition of reactive mineral compounds and CO2 fluxes, ecosystem carbon (C) and nutrient stocks, and surface water chemistry across 20 ecoâclimatic domains within the United States for 30 yr. Herein, we present the rationale and plan for the groundâbased measurements of C and nutrients in soils and plants based on overarching or âhighâlevelâ requirements agreed upon by the National Science Foundation and NEON. The resulting design incorporates early recommendations by expert review teams, as well as recent input from the larger natural sciences community that went into the formation and interpretation of the requirements, respectively. NEON\u27s efforts will focus on a suite of data streams that will enable endâusers to study and predict changes to biogeochemical cycling and transfers within and across air, land, and water systems at regional to continental scales. At each NEON site, there will be an initial, oneâtime effort to survey soil properties to 1 m (including soil texture, bulk density, pH, baseline chemistry) and vegetation community structure and diversity. A sampling program will follow, focused on capturing longâterm trends in soil C, nitrogen (N), and sulfur stocks, isotopic composition (of C and N), soil N transformation rates, phosphorus pools, and plant tissue chemistry and isotopic composition (of C and N). To this end, NEON will conduct extensive measurements of soils and plants within stratified random plots distributed across each site. The resulting data will be a new resource for members of the scientific community interested in addressing questions about longâterm changes in continentalâscale biogeochemical cycles, and is predicted to inspire further processâbased research
Behavior of the Escape Rate Function in Hyperbolic Dynamical Systems
For a fixed initial reference measure, we study the dependence of the escape
rate on the hole for a smooth or piecewise smooth hyperbolic map. First, we
prove the existence and Holder continuity of the escape rate for systems with
small holes admitting Young towers. Then we consider general holes for Anosov
diffeomorphisms, without size or Markovian restrictions. We prove bounds on the
upper and lower escape rates using the notion of pressure on the survivor set
and show that a variational principle holds under generic conditions. However,
we also show that the escape rate function forms a devil's staircase with jumps
along sequences of regular holes and present examples to elucidate some of the
difficulties involved in formulating a general theory.Comment: 21 pages. v2 differs from v1 only by additions to the acknowledgment
Effect of Mixing and Other Operating Parameters in Sol-Gel Processes
In this work the effect of mixing on a sol-gel process is quantitatively investigated. Titanium dioxide synthesis from titanium tetra-isopropoxide is used as a test reaction. Solutions of titanium alkoxide in isopropyl alcohol and water in isopropyl alcohol are mixed in a special mixing device (i.e., vortex reactor) at different mixing rates, and the effect of mixing is quantiïŹed and compared with the effect of the other relevant operating parameters, namely the water to alkoxide, acid to alkoxide ratios, and alkoxide initial concentration. Dynamic light scattering, speciïŹc surface area measurement through nitrogen adsorption, X-ray diffraction, and ïŹeld emission scanning electron microscopy are employed to determine particle size distribution, morphology, and crystallite size of the different particulate products (i.e., sols, gels, powders) obtained before and after thermal treatments under different synthesis conditions. A factorial design is used to plan the experimental campaign and results show that the role of mixing cannot be neglected. Moreover results show that mixing can be actively used to control the ïŹnal product characteristics and must be taken into account when a process is transferred from the laboratory to the industrial scale. Eventually a scale-up criterion based on our previous work will be discussed
Viral forensic genomics reveals the relatedness of classic herpes simplex virus strains KOS, KOS63, and KOS79
Herpes simplex virus 1 (HSV-1) is a widespread global pathogen, of which the strain KOS is one of the most extensively studied. Previous sequence studies revealed that KOS does not cluster with other strains of North American geographic origin, but instead clustered with Asian strains. We sequenced a historical isolate of the original KOS strain, called KOS63, along with a separately isolated strain attributed to the same source individual, termed KOS79. Genomic analyses revealed that KOS63 closely resembled other recently sequenced isolates of KOS and was of Asian origin, but that KOS79 was a genetically unrelated strain that clustered in genetic distance analyses with HSV-1 strains of North American/European origin. These data suggest that the human source of KOS63 and KOS79 could have been infected with two genetically unrelated strains of disparate geographic origins. A PCR RFLP test was developed for rapid identification of these strains
Arbaclofen in fragile X syndrome: results of phase 3 trials
Background: Arbaclofen improved multiple abnormal phenotypes in animal models of fragile X syndrome (FXS) and showed promising results in a phase 2 clinical study. The objective of the study is to determine safety and efficacy of arbaclofen for social avoidance in FXS. Methods: Two phase 3 placebo-controlled trials were conducted, a flexible dose trial in subjects age 12-50 (209FX301, adolescent/adult study) and a fixed dose trial in subjects age 5-11 (209FX302, child study). The primary endpoint for both trials was the Social Avoidance subscale of the Aberrant Behavior Checklist-Community Edition, FXS-specific (ABC-C FX ). Secondary outcomes included other ABC-C FX subscale scores, Clinical Global Impression-Improvement (CGI-I), Clinical Global Impression-Severity (CGI-S), and Vineland Adaptive Behavior Scales, Second Edition (Vineland-II) Socialization domain score. Results: A total 119 of 125 randomized subjects completed the adolescent/adult study (n = 57 arbaclofen, 62 placebo) and 159/172 completed the child study (arbaclofen 5 BID n = 38; 10 BID n = 39; 10 TID n = 38; placebo n = 44). There were no serious adverse events (AEs); the most common AEs included somatic (headache, vomiting, nausea), neurobehavioral (irritability/agitation, anxiety, hyperactivity), decreased appetite, and infectious conditions, many of which were also common on placebo. In the combined studies, there were 13 discontinuations (n = 12 arbaclofen, 1 placebo) due to AEs (all neurobehavioral). The adolescent/adult study did not show benefit for arbaclofen over placebo for any measure. In the child study, the highest dose group showed benefit over placebo on the ABC-C FX Irritability subscale (p = 0.03) and Parenting Stress Index (PSI, p = 0.03) and trends toward benefit on the ABC-C FX Social Avoidance and Hyperactivity subscales (both p < 0.1) and CGI-I (p = 0.119). Effect size in the highest dose group was similar to effect sizes for FDA-approved serotonin reuptake inhibitors (SSRIs). Conclusions: Arbaclofen did not meet the primary outcome of improved social avoidance in FXS in either study. Data from secondary measures in the child study suggests younger patients may derive benefit, but additional studies with a larger cohort on higher doses would be required to confirm this finding. The reported studies illustrate the challenges but represent a significant step forward in translating targeted treatments from preclinical models to clinical trials in humans with FXS
Stream Centric Methods for Determining Groundwater Contributions in Karst Mountain Watersheds
Climate change influences on mountain hydrology are uncertain but likely to be mediated by variability in subsurface hydrologic residence times and flow paths. The heterogeneity of karst aquifers adds complexity in assessing the resiliency of these water sources to perturbation, suggesting a clear need to quantify contributions from and losses to these aquifers. Here we develop a stream centric method that combines mass and flow balances to quantify net and gross gains and losses at different spatial scales. We then extend these methods to differentiate between karst conduit and matrix contributions from the aquifer. In the Logan River watershed in Northern Utah we found significant amounts of the river water repeatedly gained and then lost through a 35âkm study reach. Further, the direction and amount of water exchanged varied over space, time, and discharge. Streamflow was dominated by discharge of karst conduit groundwater after spring runoff with increasing, yet still small, fractions of matrix water later in the summer. These findings were combined with geologic information, prior subsurface dye tracing, and chemical sampling to provide additional lines of evidence that repeated groundwater exchanges are likely occurring and river flows are highly dependent on karst aquifer recharge and discharge. Given the large population dependent on karst aquifers throughout the world, there is a continued need to develop simple methods, like those presented here, for determining the resiliency of karst groundwater resources
Event Horizons in Numerical Relativity II: Analyzing the Horizon
We present techniques and methods for analyzing the dynamics of event
horizons in numerically constructed spacetimes. There are three classes of
analytical tools we have investigated. The first class consists of proper
geometrical measures of the horizon which allow us comparison with perturbation
theory and powerful global theorems. The second class involves the location and
study of horizon generators. The third class includes the induced horizon
2-metric in the generator comoving coordinates and a set of membrane-paradigm
like quantities. Applications to several distorted, rotating, and colliding
black hole spacetimes are provided as examples of these techniques.Comment: 23 double column pages including 28 figures. Higher quality figures
(big size!) available upon request (jmasso OR [email protected]
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