3,691 research outputs found

    PAH emission from Nova Cen 1986

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    The discovery of broad emission features between 3.2 and 3.6 microns were reported in the spectrum of Nova Cen 1986 (V842 Cen) some 300 days following outburst and remaining prominent for several months. The general characteristics of these features are similar to those attributed to polycyclic hydrocarbon (PAH) molecules in other dusty sources, although the relative strengths are different, and these observations provide the first clear evidence for molecular constituents other than graphite particles in the ejecta of novae

    Moduli and periods of simply connected Enriques surfaces

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    We describe a period map for those simply connected Enriques surfaces in characteristic 2 whose canonical double cover is K3. The moduli stack for these surfaces has a Deligne-Mumford quotient that is an open substack of a P1\mathbb P^1-bundle over the period space. We also give some general results relating local and global moduli for algebraic varieties and describe the difference in their dimensions in terms of the failure of the automorphism group scheme to be reduced

    Net selectivity for Barramundi (Lates calcarifer)

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    Log-linear modelling of two fisheries-independent barramundi catch and effort datasets (2000-2006 research survey data and 1981-1984 research survey data) from the east coast of Queensland provided estimates of selectivity of barramundi for seven mesh sizes from 101.6 mm to 203.2 mm. These estimates provide a basis for assessing the sensitivity of barramundi production model (SHASSAM) to selectivity. The two datasets were best fitted by different selection curves with a gamma selection curve providing the best fit to the 2000-2006 barramundi catch data and a lognormal selection curve for the 1891-1984 dataset. The difference in the optimum length of capture across the range of mesh sizes between these two selection curves ranged from 20 to 40 mm. However, the optimum lengths of capture for are substantially larger than reported previously for gillnet selectivity of barramundi in Fly River (Milton et al.1998). A thorough investigation of net selectivity characteristics for barramundi would require rigorous experimental design to account for factors other than mesh size including hanging ratio, filament gauge and fishing intensity and to assess entangling effects. Additional investigation is also required to investigate the relationship between contact selection and population selection to ensure appropriate catch size structure adjustment for stock assessment

    Biopsychosocial implications of living with multiple sclerosis: a qualitative study using interpretative phenomenological analysis

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    Background: Multiple sclerosis (MS) is estimated to affect 2.8 million people worldwide, with increasing prevalence in all world regions (Walton et al). While there is no cure for MS, medication and lifestyle modifications can slow disease progression and enhance patients’ quality of life. The biopsychosocial model of health recognises important interactions among biological, psychological and social factors in illness, including those relating to illness management, which contribute to the experience of those diagnosed with MS. Objective: This qualitative, idiographic study aimed to explore the lived experiences of patients in the United Arab Emirates (UAE) diagnosed with S. Methods: Semistructured interviews were conducted with a purposive sample of eight patients with MS ranging in age from 25 to 56 years. All participants were residing in the UAE at the time of data collection. Interpretative phenomenological analysis was used to analyse the data. Results: Three superordinate themes were identified from patients’ candid accounts of their lives with MS, highlighting issues of illness management, acceptance and gratitude, and adaptive coping. These themes broadly illustrate biological, psychological and social aspects of patients’ MS experiences. Conclusion: The study emphasised the importance of adopting the biopsychosocial model to treat and manage MS. Additionally, it highlights the need for routine assessment and early, multidimensional approach with multidisciplinary team efforts to improve patients’ quality of life

    Design and implementation of robust decentralized control laws for the ACES structure at Marshall Space Flight Center

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    Many large space system concepts will require active vibration control to satisfy critical performance requirements such as line-of-sight accuracy. In order for these concepts to become operational it is imperative that the benefits of active vibration control be practically demonstrated in ground based experiments. The results of the experiment successfully demonstrate active vibration control for a flexible structure. The testbed is the Active Control Technique Evaluation for Spacecraft (ACES) structure at NASA Marshall Space Flight Center. The ACES structure is dynamically traceable to future space systems and especially allows the study of line-of-sight control issues

    French Nuclear Forces

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    Declared French nuclear strategy rests today on the Gaullist doctrine of proportional deterrence elaborated more than two decades ago. Proportional deterrence doctrine states a weak state (France) can deter a strong state (USSR) when the weak nation possesses the capability to inflict enough damage on the strong one so that the value of the conquest of the weak country to the strong one is less than the value of the damage which the weak can inflict on the strong

    Observations of deep coral and sponge assemblages in Olympic Coast National Marine Sanctuary, Washington. Cruise Report: NOAA Ship McArthur II Cruise AR06-07/07

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    From May 22 to June 4, 2006, NOAA scientists led a research cruise using the ROPOS Remotely Operated Vehicle (ROV) to conduct a series of dives at targeted sites in the Olympic Coast National Marine Sanctuary (OCNMS) with the goal of documenting deep coral and sponge communities. Dive sites were selected from areas for which OCNMS had side scan sonar data indicating the presence of hard or complex substrate. The team completed 11 dives in sanctuary waters ranging from six to 52 hours in length, at depths ranging from 100 to 650 meters. Transect surveys were completed at 15 pre-selected sites, with additional observations made at five other sites. The survey locations included sites both inside and outside the Essential Fish Habitat (EFH) Conservation Area, known as Olympic 2, established by the Pacific Fishery Management Council, enacted on June 12, 2006. Bottom trawling is prohibited in the Olympic 2 Conservation Area for nontribal fishermen. The Conservation Area covers 159.4 square nautical miles or about 15 percent of the sanctuary. Several species of corals and sponges were documented at 14 of the 15 sites surveyed, at sites both inside and outside the Conservation Area, including numerous gorgonians and the stony corals Lophelia pertusa and Desmophyllum dianthus, as well as small patches of the reef building sponge Farrea occa. The team also documented Lophelia sp. and Desmophyllum sp. coral rubble, dead gorgonians, lost fishing gear, and other anthropogenic debris, supporting concerns over potential risks of environmental disturbances to coral health. (PDF contains 60 pages.

    Atmospheric effects on the underground muon intensity

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    It has previously been reported that the barometric pressure coefficient observed for muons at Poatina (vertical absorber depth 357 hg/sq cm) appears to be appreciably higher than would be expected from atmospheric absorption alone. There is a possibility that the effect is due to an upper atmospheric temperature effect arising from an inverse correlation of surface pressure with stratospheric temperature. A new proportional telescope is discussed which has been operating at Poatina since about the beginning of 83 and which has a long term stability suitable for studying variations of atmospheric origin
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