32,838 research outputs found

    Comparative Response of Two Hydrilla Strains to Fluridone

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    Experiments were conducted in a controlled-environmental growth chamber to evaluate the response of two strains of the invasive submersed plant Hydrilla verticillata (L.f.) Royle to fluridone (1-methyl-3-phenyl-5-[3-trifluoromethyl)phenyl]- 4(1H)-pyridinone). (PDF has 6 pages.

    The XMM-Newton spectral-fit database

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    The XMM-Newton spectral-fit database is an ongoing ESA funded project aimed to construct a catalogue of spectral-fitting results for all the sources within the XMM-Newton serendipitous source catalogue for which spectral data products have been pipeline-extracted (~ 120,000 X-ray source detections). The fundamental goal of this project is to provide the astronomical community with a tool to construct large and representative samples of X-ray sources by allowing source selection according to spectral properties.Comment: Conference proceedings of IAU Symposium 304: Multiwavelength AGN surveys and studie

    The Role of Connexins and Pannexins in Mammary Gland Development and Tumorigenesis

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    The identification of key regulators of breast cancer onset and progression is critical for the development of targeted therapies. Connexins and pannexins are characterized by their ability to form large-pore channels and are frequently dysregulated in cancer. However, their role in breast cancer progression remains poorly understood due to a lack of in vivo models capable of assessing the proposed and opposing roles of connexins and pannexins as both tumor suppressors and/or facilitators in multiple stages of the disease. Using 2 previously uncharacterized genetically-modified mice, connexin43 (Cx43) and connexin26 (Cx26) were evaluated for their role in normal mammary gland development and function prior to using the mice to assess their linkage to breast cancer onset and progression. In addition, pannexin1 (Panx1) was evaluated for the first time in the context of mammary gland development and correlated to clinical outcomes in patients with breast cancer using in silico arrays. Using a mouse model expressing a loss-of-function Cx43 mutant it was revealed that the severity of milk ejection defects associated with Cx43 are linked to its functional status. Using a similar mouse model induced to develop primary breast cancer lesions, we identified that low functional levels of Cx43 resulted in mainly hyperplasic mammary glands that greatly increased the frequency of developing metastases to the lungs. Our assessment of mice with conditional knockdown of Cx26 during pregnancy revealed that basal levels of Cx26 were sufficient for normal alveolar development and proper lactation, but increased the susceptibility of mammary tumor onset in a chemically induced mouse model of breast cancer. Finally, genetically modified mice with systemic knockout of Panx1 identified a role for Panx1 in timely alveolar development during early lactation. In addition, Panx1 mRNA expression was correlated with worse clinical outcomes in breast cancer. Collectively, our results redefine our view of Cx43, Cx26 and Panx1 in mammary gland development; supporting a tumor suppressive role for Cx43 and Cx26, and a tumor facilitating role for Panx1 in breast cancer progression which may have implications for extending to their use as therapeutic targets

    Gas sensing based on optical fibre coupled diode laser spectroscopy : a new approach to sensor systems for safety monitoring

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    We describe an entirely passive fibre optic network which senses, amongst other species, CH¬4¬ and CO¬¬2 , with sensitivity and selectivity compatible with safety sensing in the mine environment. The basic principle is that a single laser diode source targeted to a particular species addresses up to 200 sensing points which may be spread over an area of dimensions ten or more km. The detection and processing electronics is typically located with the laser source. Several laser sources can be introduced in parallel to enable monitoring multiple species. The network itself, entirely linked through optical fibre, is inherently intrinsically safe. It is self checking for faults at the sensing location and continuously self calibrating. In the methane sensing mode its sensitivity is sub 100ppm and it responds accurately up to 100% methane. It is therefore capable of detecting extremely hazardous gas pockets which are completely missed by other sensor technologies. The network has demonstrated stability with zero maintenance or recalibration over periods in excess of two years. We believe that this system offers unique benefits in the context of mine safety and ventilation system monitoring

    The asymptotic quasi-stationary states of the two-dimensional magnetically confined plasma and of the planetary atmosphere

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    We derive the differential equation governing the asymptotic quasi-stationary states of the two dimensional plasma immersed in a strong confining magnetic field and of the planetary atmosphere. These two systems are related by the property that there is an intrinsic constant length: the Larmor radius and respectively the Rossby radius and a condensate of the vorticity field in the unperturbed state related to the cyclotronic gyration and respectively to the Coriolis frequency. Although the closest physical model is the Charney-Hasegawa-Mima (CHM) equation, our model is more general and is related to the system consisting of a discrete set of point-like vortices interacting in plane by a short range potential. A field-theoretical formalism is developed for describing the continuous version of this system. The action functional can be written in the Bogomolnyi form (emphasizing the role of Self-Duality of the asymptotic states) but the minimum energy is no more topological and the asymptotic structures appear to be non-stationary, which is a major difference with respect to traditional topological vortex solutions. Versions of this field theory are discussed and we find arguments in favor of a particular form of the equation. We comment upon the significant difference between the CHM fluid/plasma and the Euler fluid and respectively the Abelian-Higgs vortex models.Comment: Latex 126 pages, 7 eps figures included. Discussion on various forms of the equatio

    Evaluating Dryland Crop/Livestock System Alternatives for Risk Management under Declining Irrigation in the Texas Panhandle

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    Production budgets for dryland crop and crop/livestock systems are developed to estimate yields, costs and returns for dryland wheat and sorghum and for alternative dryland crop/livestock systems. A crop simulation model aids yield estimation. The yield and return distributions are used to estimate risk and relative risk for included alternatives.Relative Risk, Ogallala Aquifer, Crop-Livestock Systems, Wheat, Sorghum, Crop Production/Industries, Farm Management, Livestock Production/Industries, Production Economics, Productivity Analysis,

    Perspectives on financial incentives to health service providers for increasing breast feeding and smoking quit rates during pregnancy: a mixed methods study

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    Objective: To explore the acceptability, mechanisms and consequences of provider incentives for smoking cessation and breast feeding as part of the Benefits of Incentives for Breastfeeding and Smoking cessation in pregnancy (BIBS) study. Design: Cross-sectional survey and qualitative interviews. Setting: Scotland and North West England. Participants: Early years professionals: 497 survey respondents included 156 doctors; 197 health visitors/maternity staff; 144 other health staff. Qualitative interviews or focus groups were conducted with 68 pregnant/postnatal women/family members; 32 service providers; 22 experts/decision-makers; 63 conference attendees. Methods: Early years professionals were surveyed via email about the acceptability of payments to local health services for reaching smoking cessation in pregnancy and breastfeeding targets. Agreement was measured on a 5-point scale using multivariable ordered logit models. A framework approach was used to analyse free-text survey responses and qualitative data. Results: Health professional net agreement for provider incentives for smoking cessation targets was 52.9% (263/497); net disagreement was 28.6% (142/497). Health visitors/maternity staff were more likely than doctors to agree: OR 2.35 (95% CI 1.51 to 3.64; p<0.001). Net agreement for provider incentives for breastfeeding targets was 44.1% (219/497) and net disagreement was 38.6% (192/497). Agreement was more likely for women (compared with men): OR 1.81 (1.09 to 3.00; p=0.023) and health visitors/maternity staff (compared with doctors): OR 2.54 (95% CI 1.65 to 3.91; p<0.001). Key emergent themes were 'moral tensions around acceptability', 'need for incentives', 'goals', 'collective or divisive action' and 'monitoring and proof'. While provider incentives can focus action and resources, tensions around the impact on relationships raised concerns. Pressure, burden of proof, gaming, box-ticking bureaucracies and health inequalities were counterbalances to potential benefits. Conclusions: Provider incentives are favoured by non-medical staff. Solutions which increase trust and collaboration towards shared goals, without negatively impacting on relationships or increasing bureaucracy are required

    Electronic and Magnetic Properties of Electron-doped Superconductor, Sm_{1.85}Ce_{0.15}CuO_{4-delta}

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    Temperature-dependent magnetization (M(T)) and specific heat (C_p(T)) measurements were carried out on single crystal Sm_{1.85}Ce_{0.15}CuO_{4-delta} (T_c = 16.5 K). The magnetic anisotropy in the static susceptibility, chi {equiv} M/H, is apparent not only in its magnitude but also in its temperature dependence, with chi_{perp} for H{perp}c larger than chi_{parallel} for H{parallel}c. For both field orientations, chi does not follow the Curie-Weiss behavior due to the small energy gap of the J = 7/2 multiplet above the J = 5/2 ground-state multiplet. However, with increasing temperature, chi_{parallel}(T) exhibits a broad minimum near 100 K and then a slow increase while chi_{perp}(T) shows a monotonic decrease. A sharp peak in C_p(T) at 4.7 K manifests an antiferromagnetic ordering. The electronic contribution, gamma, to C_p(T) is estimated to be gamma = 103.2 (7) mJ/moleSmK^2. The entropy associated with the magnetic ordering is much smaller than Rln2, where R is the gas constant, which is usually expected for the doublet ground state of Sm^{+3}. The unusual magnetic and electronic properties evident in M(T) and C_p(T) are probably due to a strong anisotropic interaction between conduction electrons and localized electrons at Sm^{+3} sites.Comment: 5 pages, 5 encapsulated postscript figures, late
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