5,540 research outputs found

    Cassini detection of Enceladus' cold water-group plume ionosphere

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    This study reports direct detection by the Cassini plasma spectrometer of freshly-produced water-group ions (O+, OH+, H2O+, H3O+) and heavier water dimer ions (HxO(2))(+) very close to Enceladus where the plasma begins to emerge from the plume. The data were obtained during two close ( 52 and 25 km) flybys of Enceladus in 2008 and are similar to ion data in cometary comas. The ions are observed in detectors looking in the Cassini ram direction exhibiting energies consistent with the Cassini speed, indicative of a nearly stagnant plasma flow in the plume. North of Enceladus the plasma slowing commences about 4 to 6 Enceladus radii away, while south of Enceladus signatures of the plasma interaction with the plume are detected 22 Enceladus radii away. Citation: Tokar, R. L., R. E. Johnson, M. F. Thomsen, R. J. Wilson, D. T. Young, F. J. Crary, A. J. Coates, G. H. Jones, and C. S. Paty ( 2009), Cassini detection of Enceladus' cold water-group plume ionosphere, Geophys. Res. Lett., 36, L13203, doi:10.1029/2009GL038923

    A global review of animal translocation programs

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    We performed a bibliometric analysis to investigate the efficiency of release techniques (soft and hard–release), to analyse the characteristics and outcomes of the translocation programs, to identify knowledge gaps, and to provide recommendations. Animal conservation studies involving animal release to the wild increased significantly over the 31 years studied and were more frequently performed with terrestrial mammals than with other taxonomic groups. Most of the studies were performed by researchers from developed countries. Translocations occurred mostly in temperate regions, with almost no translocations occurring in the tropics. Almost 60 % of the studies did not provide information regarding the success or failure of the translocation programs. The most commonly used technique was hard release. Wild–caught specimens were preferred for translocations. Translocation programs were less common for groups like amphibians, fishes, and invertebrates. If criteria for suitable translocation are met, this management tool should also be conducted for tropical threatened species, led by native researchers. Furthermore, criteria for successful translocation should be clearly identified in order to improve future conservation actions

    Failure to activate the IFN-beta promoter by a paramyxovirus lacking an interferon antagonist

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    It is generally thought that pathogen-associated molecular patterns (PAMPs) responsible for triggering interferon (IFN) induction are produced during virus replication and, to limit the activation of the IFN response by these PAMPs, viruses encode antagonists of IFN induction. Here we have studied the induction of IFN by parainfluenza virus type 5 (PIV5) at the single-cell level, using a cell line expressing GFP under the control of the IFN-β promoter. We demonstrate that a recombinant PIV5 (termed PIV5-VΔC) that lacks a functional V protein (the viral IFN antagonist) does not activate the IFN-β promoter in the majority of infected cells. We conclude that viral PAMPs capable of activating the IFN induction cascade are not produced or exposed during the normal replication cycle of PIV5, and suggest instead that defective viruses are primarily responsible for inducing IFN during PIV5 infection in this syste

    Successful strategies for engaging Chinese breast cancer survivors in a randomized controlled trial

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    This is the author accepted manuscript. The final version is available from the American Psychological Association via the DOI in this record.Chinese immigrant breast cancer survivors face various challenges due to cultural and socioecological factors. Research efforts to develop culturally sensitive interventions have been limited by lack of knowledge regarding successful recruitment and implementation practices among Chinese immigrant populations. This paper documents strategies utilized during the development and implementation of a randomized controlled trial of a culturally sensitive psychosocial intervention for Chinese immigrant breast cancer survivors. In partnership with a community agency, we developed culturally and linguistically appropriate research materials, recruited participants from community channels, and conducted longitudinal data collection. Key strategies include building equitable research partnerships with community agencies to engage participants; being responsive to the needs of community agencies and participants; considering within-group diversity of the research population; utilizing recruitment as an opportunity for relationship-building with participants; and developing key strategies to promote retention. Successful participant engagement in cancer intervention research is the result of collaboration among breast cancer survivors, community leaders and agencies, and academic researchers. The engagement process for this study is novel because we have emphasized cultural factors in the process and taken a relational approach to recruitment and retention

    Animal personality and conservation : basics for inspiring new research

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    The number of animal species threatened with extinction are increasing every year, and biologists are conducting animal translocations, as one strategy, to try to mitigate this situation. Furthermore, researchers are evaluating methods to increase translocation success, and one area that shows promise is the study of animal personality. Animal personality can be defined as behavioral and physiological differences between individuals of the same species, which are stable in time and across different contexts. In the present paper, we discuss how animal personality can increase the success of translocation, as well as in the management of animals intended for translocation by evaluating personality characteristics of the individuals. Studies of the influence of birthplace, parental behavior, stress resilience, and risk assessment can be important to select the most appropriate individuals to be released. Finally, we explain the two methods used to gather personality data

    Long-term high frequency measurements of ethane, benzene and methyl chloride at Ragged Point, Barbados: Identification of long-range transport events

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    Abstract Here we present high frequency long-term observations of ethane, benzene and methyl chloride from the AGAGE Ragged Point, Barbados, monitoring station made using a custom built GC-MS system. Our analysis focuses on the first three years of data (2005–2007) and on the interpretation of periodic episodes of high concentrations of these compounds. We focus specifically on an exemplar episode during September 2007 to assess if these measurements are impacted by long-range transport of biomass burning and biogenic emissions. We use the Lagrangian Particle Dispersion model, NAME, run forwards and backwards in time to identify transport of air masses from the North East of Brazil during these events. To assess whether biomass burning was the cause we used hot spots detected using the MODIS instrument to act as point sources for simulating the release of biomass burning plumes. Excellent agreement for the arrival time of the simulated biomass burning plumes and the observations of enhancements in the trace gases indicates that biomass burning strongly influenced these measurements. These modelling data were then used to determine the emissions required to match the observations and compared with bottom up estimates based on burnt area and literature emission factors. Good agreement was found between the two techniques highlight the important role of biomass burning. The modelling constrained by in situ observations suggests that the emission factors were representative of their known upper limits, with the in situ data suggesting slightly greater emissions of ethane than the literature emission factors account for. Further analysis was performed concluding only a small role for biogenic emissions of methyl chloride from South America impacting measurements at Ragged Point. These results highlight the importance of long-term high frequency measurements of NMHC and ODS and highlight how these data can be used to determine sources of emissions 1000’s km away.ATA would like to thank the GWR and the Met Office for the PhD funding that was useful in the initiation of this research and the Herchel Smith foundation for a Postdoctoral fellowship, and NCAS for funding. The operation of the AGAGE station at Ragged Point is supported by the National Aeronautic and Space Administration (NASA, USA) (grants NNX07AE89G and NNX11AF17G to MIT) and the National Oceanic and Atmospheric Administration (NOAA, USA) (contract RA133R09CN0062).This is the final version of the article. It first appeared from BioOne via http://dx.doi.org/10.12952/journal.elementa.00006

    The inevitable youthfulness of known high-redshift radio galaxies

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    Radio galaxies can be seen out to very high redshifts, where in principle they can serve as probes of the early evolution of the Universe. Here we show that for any model of radio-galaxy evolution in which the luminosity decreases with time after an initial rapid increase (that is, essentially all reasonable models), all observable high-redshift radio-galaxies must be seen when the lobes are less than 10^7 years old. This means that high-redshift radio galaxies can be used as a high-time-resolution probe of evolution in the early Universe. Moreover, this result helps to explain many observed trends of radio-galaxy properties with redshift [(i) the `alignment effect' of optical emission along radio-jet axes, (ii) the increased distortion in radio structure, (iii) the decrease in physical sizes, (iv) the increase in radio depolarisation, and (v) the increase in dust emission] without needing to invoke explanations based on cosmology or strong evolution of the surrounding intergalactic medium with cosmic time, thereby avoiding conflict with current theories of structure formation.Comment: To appear in Nature. 4 pages, 2 colour figures available on request. Also available at http://www-astro.physics.ox.ac.uk/~km

    Ionospheric electrons in Titan's tail: Plasma structure during the cassini T9 encounter

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    We present results from the CAPS electron spectrometer obtained during the downstream flyby of Titan on 26 December 2005, which occurred during a period of enhanced plasma pressure inside the magnetosphere. The electron data show an unusual split signature with two principal intervals of interest outside the nominal corotation wake. Interval 1 shows direct evidence for ionospheric plasma escape at several RT in Titan's tail. Interval 2 shows a complex plasma structure, a mix between plasma of ionospheric and magnetospheric origin. We suggest a mechanism for plasma escape based on ambipolar electric fields set up by suprathermal ionospheric photoelectrons

    Impacts of food-based enrichment on behaviour and physiology of male greater rheas (Rhea Americana, Rheidae, Aves)

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    Distress can be defined as a biological response of an individual to long-term threats to its homeostasis and it should be avoided from an animal welfare perspective. High levels of stress hormones and the expression of abnormal behaviours are responses normally observed in distressed animals. Captive environments can provoke distress, especially when inappropriate stimuli are provided to the animals. The concomitant use of behavioural and non-invasive hormonal measures is a means to evaluate captive animal welfare. Environmental enrichment is a tool that can reduce distress and minimize the expression of abnormal behaviour in captive animals. The aim of this study was to evaluate greater rheas’ responses (behavioral and hormonal) to food-based enrichment. Three birds from the Belo Horizonte Zoo, Brazil were studied. The study was divided into three phases (baseline, enrichment and post-enrichment): fruits scattered around the birds’ enclosure were used as enrichment. Behaviour and faecal sampling were undertaken in all phases of the study. Abnormal behaviours and faecal glucocorticoid metabolites (GCM) levels showed significant reduction during the environmental enrichment phase, and a significative positive correlation between GCM production and abnormal pacing was observed. From the results of this study, we conclude that the use of food as environmental enrichment should be encouraged because of its positive effects on animal welfare. Besides, studies with larger groups of greater rheas, with individuals of both sexes, should also be encouraged to evaluate if the results found in this pilot study are consistent and can be generalized to the species

    Three-dimensional scapular morphology is associated with rotator cuff tears and alters the abduction moment arm of the supraspinatus.

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    BACKGROUND: Numerous studies have reported an association between rotator cuff injury and two-dimensional measures of scapular morphology. However, the mechanical underpinnings explaining how these shape features affect glenohumeral joint function and lead to injury are poorly understood. We hypothesized that three-dimensional features of scapular morphology differentiate asymptomatic shoulders from those with rotator cuff tears, and that these features would alter the mechanical advantage of the supraspinatus. METHODS: Twenty-four individuals with supraspinatus tears and twenty-seven age-matched controls were recruited. A statistical shape analysis identified scapular features distinguishing symptomatic patients from asymptomatic controls. We examined the effect of injury-associated morphology on mechanics by developing a morphable model driven by six degree-of-freedom biplanar videoradiography data. We used the model to simulate abduction for a range of shapes and computed the supraspinatus moment arm. FINDINGS: Rotator cuff injury was associated with a cranial orientation of the glenoid and scapular spine (P = .011, d = 0.75) and/or decreased subacromial space (P = .001, d = 0.94). The shape analysis also identified previously undocumented features associated with superior inclination and subacromial narrowing. In our computational model, warping the scapula from a cranial to a lateral orientation increased the supraspinatus moment arm at 20° of abduction and decreased the moment arm at 160° of abduction. INTERPRETATIONS: Three-dimensional analysis of scapular morphology indicates a stronger relationship between morphology and cuff tears than two-dimensional measures. Insight into how morphological features affect rotator cuff mechanics may improve patient-specific strategies for prevention and treatment of cuff tears
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