185 research outputs found

    Raccoon (\u3cem\u3eProcyon lotor\u3c/em\u3e) Diets Shed Light on Baylisascaris procyonis Roundworm Prevalence

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    The raccoon, Procyon lotor, is the definitive host for raccoon roundworm (Baylisascaris procyonis), which causes a dangerous neurological disease known as larva migrans encephalopathy in intermediate hosts. As omnivores, raccoons rely on a variety of food items. Parasitized animals may exhibit altered eating habits and diets, and may undergo genetic variations as a result of parasite abundance. In this study, we analyzed the diets of necropsied raccoons from nine townships of Clark and Greene Counties, Ohio, by examining their stomach contents. We measured the mass of plant material found in raccoon stomachs and recorded the prevalence of B. procyonis. Mean mass of plant material varied among the nine townships surveyed (0.88g – 6.40g), indicating a correlation between raccoon diet and regional landscape. The townships with the least amount of agriculture had the greatest difference between all raccoons and B. procyonis infected raccoons (r²= 0.40). These results suggest that the complexity of raccoon diet exceeds that which can be explained by agricultural landscape alone. These findings help us better understand the relationship between B. procyonis and raccoon diet, therefore helping us to understand the ecological impacts of parasites on animal behavior

    De novo origins of multicellularity in response to predation

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    The transition from unicellular to multicellular life was one of a few major events in the history of life that created new opportunities for more complex biological systems to evolve. Predation is hypothesized as one selective pressure that may have driven the evolution of multicellularity. Here we show that de novo origins of simple multicellularity can evolve in response to predation. We subjected outcrossed populations of the unicellular green alga Chlamydomonas reinhardtii to selection by the filter-feeding predator Paramecium tetraurelia. Two of five experimental populations evolved multicellular structures not observed in unselected control populations within ~750 asexual generations. Considerable variation exists in the evolved multicellular life cycles, with both cell number and propagule size varying among isolates. Survival assays show that evolved multicellular traits provide effective protection against predation. These results support the hypothesis that selection imposed by predators may have played a role in some origins of multicellularity

    Mutations In SID2, A Novel Gene In Saccharomyces Cerevisiae, Cause Synthetic Lethality With Sic1 Deletion And May Cause A Defect During S Phase

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    SIC1 encodes a nonessential B-type cyclin/CDK inhibitor that functions at the G1/S transition and the exit from mitosis. To understand more completely the regulation of these transitions, Mutations causing synthetic lethality with sic1 Delta were isolated. In this screen, we identified a novel gene, SID2, which encodes an essential protein that appear., to be required for DNA replication or repair. sid2-1 sic1 Delta strains and sid2-21 temperature-sensitive strains arrest preanaphase as large-budded cells with a single nucleus, a short spindle, and an similar to 2C DNA content. RAD9, which is necessary for the DNA damage checkpoint, is required for the preanaphase arrest of sid2-1 sic1 Delta cells. Analysis of chromosomes in mutant sid2-21 cells by field inversion gel clectropiioresis suggests the presence of replication forks and bubbles at the arrest. Deleting the two S phase cyclins, CLB5 and CLB6, substantially suppresses the sid2-1 sir1 Delta inviability, while stabilizing Clb5 protein exacerbates the defects of sid2-1 sic1 Delta, cells. In synchronized sid2-1 mutant strains, the onset of replication appears normal, but completion of DNA synthesis is delayed. sid2-1 mutants are sensitive to hydroxytirea indicating that sid2-1 cells may suffer DNA damage that, when combined with additional insult, leads to a decrease in viability. Consistent with this hypothesis, sid2-1 rad9 cells are dead or very slow growing even when SIC1 is expressed

    Monitoring brown trout (Salmo trutta) eradication in a wildlife sanctuary using environmental DNA

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    Restoration of habitats often necessitates the eradication of exotic animals from a specified area. One of the many challenges associated with the removal of introduced animals is determining the distribution and continued presence of individuals in order to efficiently target control operations and minimise any adverse effects associated with removal. We examined the feasibility of using environmental DNA (eDNA) from water samples, relative to more traditional electric fishing, netting and spotlight surveys (i.e., visual observations of the small streams at night), to determine the presence of brown trout. Samples were taken from within the Zealandia Sanctuary near Wellington, New Zealand, before and after treatment with the piscicide rotenone. Using filtration of water samples, we successfully extracted brown trout DNA from water both before and after rotenone treatment. In most cases, DNA presence corresponded to results obtained through netting and spotlight surveys, and in one instance detected the continued presence of trout in a treated stream (which was subsequently confirmed). We conclude that the use of environmental DNA to detect the presence of exotic fish can be a useful tool to assist in the assessment and restoration of aquatic habitats

    Benchmark Parameters for CMB Polarization Experiments

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    The recently detected polarization of the cosmic microwave background (CMB) holds the potential for revealing the physics of inflation and gravitationally mapping the large-scale structure of the universe, if so called B-mode signals below 10^{-7}, or tenths of a uK, can be reliably detected. We provide a language for describing systematic effects which distort the observed CMB temperature and polarization fields and so contaminate the B-modes. We identify 7 types of effects, described by 11 distortion fields, and show their association with known instrumental systematics such as common mode and differential gain fluctuations, line cross-coupling, pointing errors, and differential polarized beam effects. Because of aliasing from the small-scale structure in the CMB, even uncorrelated fluctuations in these effects can affect the large-scale B modes relevant to gravitational waves. Many of these problems are greatly reduced by having an instrumental beam that resolves the primary anisotropies (FWHM << 10'). To reach the ultimate goal of an inflationary energy scale of 3 \times 10^{15} GeV, polarization distortion fluctuations must be controlled at the 10^{-2}-10^{-3} level and temperature leakage to the 10^{-4}-10^{-3} level depending on effect. For example pointing errors must be controlled to 1.5'' rms for arcminute scale beams or a percent of the Gaussian beam width for larger beams; low spatial frequency differential gain fluctuations or line cross-coupling must be eliminated at the level of 10^{-4} rms.Comment: 11 pages, 5 figures, submitted to PR

    Cosmic 21-cm Fluctuations as a Probe of Fundamental Physics

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    Fluctuations in high-redshift cosmic 21-cm radiation provide a new window for observing unconventional effects of high-energy physics in the primordial spectrum of density perturbations. In scenarios for which the initial state prior to inflation is modified at short distances, or for which deviations from scale invariance arise during the course of inflation, the cosmic 21-cm power spectrum can in principle provide more precise measurements of exotic effects on fundamentally different scales than corresponding observations of cosmic microwave background anisotropies.Comment: 8 pages, 2 figure

    Evaluation of an Atmosphere Revitalization Subsystem for Deep Space Exploration Missions

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    An Atmosphere Revitalization Subsystem (ARS) suitable for deployment aboard deep space exploration mission vehicles has been developed and functionally demonstrated. This modified ARS process design architecture was derived from the International Space Station's (ISS) basic ARS. Primary functions considered in the architecture include trace contaminant control, carbon dioxide removal, carbon dioxide reduction, and oxygen generation. Candidate environmental monitoring instruments were also evaluated. The process architecture rearranges unit operations and employs equipment operational changes to reduce mass, simplify, and improve the functional performance for trace contaminant control, carbon dioxide removal, and oxygen generation. Results from integrated functional demonstration are summarized and compared to the performance observed during previous testing conducted on an ISS-like subsystem architecture and a similarly evolved process architecture. Considerations for further subsystem architecture and process technology development are discussed

    A Climatology of Cold-Season Nonconvective Wind Events in the Great Lakes Region

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    A 44-yr climatology of nonconvective wind events (NCWEs) for the Great Lakes region has been created using hourly wind data for 38 first-order weather stations during the months of November through April. The data were analyzed in terms of the two National Weather Service (NWS) criteria for a high-wind watch or warning: sustained winds of at least 18 m s-1for at least 1 h or a wind gust of at least 26 m s-1for any duration. The results indicate a pronounced southwest quadrant directional preference for nonconvective high winds in this region. Between 70% and 76% of all occurrences that satisfied the NWS criteria for NCWEs were associated with wind directions from 180° through 270°. Within the southwest quadrant, the west-southwest direction is preferred, with 14%-35% of all NCWEs coming from this particular compass heading. This directional preference is borne out in five out of six stations with high occurrences of cold-season NCWEs (Buffalo, New York; Dayton, Ohio; Lansing, Michigan; Moline, Illinois; Springfield, Illinois). Given the geographic spread of these stations, a nontopographic cause for the directional preference of cold-season NCWEs is indicated. The connection between NCWEs and low pressure systems found in this climatology and in case studies suggests that midlatitude cyclone dynamics may be a possible cause of the directional preference

    Comparative route of administration studies using therapeutic siRNAs show widespread gene modulation in Dorset sheep

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    siRNAs comprise a class of drugs that can be programmed to silence any target gene. Chemical engineering efforts resulted in development of divalent siRNAs (di-siRNAs), which support robust and long-term efficacy in rodent and nonhuman primate brains upon direct cerebrospinal fluid (CSF) administration. Oligonucleotide distribution in the CNS is nonuniform, limiting clinical applications. The contribution of CSF infusion placement and dosing regimen on relative accumulation, specifically in the context of large animals, is not well characterized. To our knowledge, we report the first systemic, comparative study investigating the effects of 3 routes of administration - intrastriatal (i.s.), i.c.v., and intrathecal catheter to the cisterna magna (ITC) - and 2 dosing regimens - single and repetitive via an implanted reservoir device - on di-siRNA distribution and accumulation in the CNS of Dorset sheep. CSF injections (i.c.v. and ITC) resulted in similar distribution and accumulation across brain regions. Repeated dosing increased homogeneity, with greater relative deep brain accumulation. Conversely, i.s. administration supported region-specific delivery. These results suggest that dosing regimen, not CSF infusion placement, may equalize siRNA accumulation and efficacy throughout the brain. These findings inform the planning and execution of preclinical and clinical studies using siRNA therapeutics in the CNS
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