3,789 research outputs found

    Low frequency creep in CoNiFe films

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    The results of an investigation of domain wall motion excited by slow rise-time, bipolar, hard-axis pulses in vacuum deposited CoNiFe films 1500A to 2000A thick are presented. The results are consistent with those of comparable NiFe films in spite of large differences in film properties. The present low frequency creep data together with previously published results in this and other laboratories can be accounted for by a model which requires that the wall structure change usually associated with low frequency creep be predominately a gyromagnetic process. The correctness of this model is reinforced by the observation that the wall coercive force, the planar wall mobility, and the occurrence of an abrupt wall structure change are the only properties closely correlated to the creep displacement characteristics of a planar wall in low dispersion films

    Soils of Clay County South Dakota

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    The Clay County soil survey is an inventory of the soil resources found in that area. It is designed to help answer questions such as: What soil types do I have on my farm? Do different soil types need different management practices? If so, what are the suggested practices? Are certain crops better adapted to different soil types? Do soil types have different yield potentials? Published soil surveys are made up of two parts: a map and a report. The Clay County soil map, bound in the middle of the report, shows the location and extent of the various soils in the county. Descriptions of each of the soils shown on the map and the suggested management practices for each are given in the report. Tables are included which list estimated yields of principal crops for each soil, the general agricultural rating for each soil, specific management recommendations, and suitability for irrigation

    The shock compression of microorganism-loaded broths and emulsions: Experiments and simulations

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    By carefully selecting flyer plate thickness and the geometry of a target capsule for bacterial broths and emulsions, we have successfully subjected the contents of the capsule to simultaneous shock and dynamic compression when subjected to a flyer-plate impact experiment. The capsules were designed to be recovered intact so that post experimental analysis could be done on the contents. ANSYS® AUTODYN hydrocode simulations were carried out to interrogate the deformation of the cover plate and the wave propagation in the fluid. Accordingly, we have shown that microorganisms such as Escherichia coli, Enterococcus faecalis and Zygosaccharomyces bailii are not affected by this type of loading regime. However, by introducing a cavity behind the broth we were able to observe limited kill in the yeast sample. Further, on using this latter technique with emulsions it was shown that greater emulsification of an oil-based emulsion occurred due to the cavitation that was introduced

    The shock Hugoniot of hydroxy-terminated polybutadiene

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    The response of polymers to shock loading is becoming of increasing importance, both as binder systems in plastic-bonded explosives (PBXs) and as structural materials in their own right. In this paper, we report on the shock Hugoniot of hydroxy-terminated polybutadiene (HTPB), which is commonly used as a binder system in PBXs, but whose shock response has yet to be presented in the open literature. Results indicate that the shock velocity --- particle velocity relationship is linear, similar to some but not all polymer-based materials

    What do you need? 2007-08 findings from a national survey of people with diagnosed HIV

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    Over the past twenty-five years, both the needs of people with diagnosed HIV and our understanding of them have changed dramatically. During this time there have been many assessments of need, usually within specific geographic boundaries (such as Primary Care Trusts) but no consistent approach to describing needs has been adopted. Most needs assessments have been shaped by a variety of local factors, including the profile of existing services. This study provides an insight into the needs of people with diagnosed HIV living in the UK, based on a final sample of 1777 people. The approach taken to measuring and describing need is the same as our previous national survey (Weatherburn et al. 2002). This approach was shaped by our earlier qualitative studies exploring the experience of people with diagnosed HIV in the early days of anti-HIV treatments (Anderson et al. 2000, Anderson & Weatherburn 1999, Anderson & Weatherburn 1998). While this study uses the same methods as our 2001-2002 survey we do not draw direct comparisons with our previous data or discuss change over time. The limitations of self-completion surveys using convenience samples make change comparisons hazardous. However, it is worth noting that in any comparison with our prior data (Weatherburn et al. 2002) current levels of need very rarely seem lower than we have previously reported. The range and extent of medical and social care, support and information needs we present here reveal significant challenges for service commissioners and providers. The first challenge is to avoid drawing quick conclusions about what the patterns of need mean for service commissioning and delivery. Needs have deliberately been separated from service use because the question of what services are ‘needed’ cannot be answered simply by identifying the extent of personal needs. The overall pattern of need is a useful starting point, but this pattern is complex

    Plus One: HIV diagnosis and disclosure

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    Plus One: HIV sero-discordant relationships among black African people in England (NAHIP) Duration: September 2010 - November 2011 Plus One involved in-depth, face-to-face interviews with black African people living in England who were in relationships where one person had diagnosed HIV and the other did not (ie. HIV serodiscordant)

    The VANDELS survey: Dust attenuation in star-forming galaxies at z=3−4\mathbf{z=3-4}

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    We present the results of a new study of dust attenuation at redshifts 3<z<43 < z < 4 based on a sample of 236236 star-forming galaxies from the VANDELS spectroscopic survey. Motivated by results from the First Billion Years (FiBY) simulation project, we argue that the intrinsic spectral energy distributions (SEDs) of star-forming galaxies at these redshifts have a self-similar shape across the mass range 8.2≤8.2 \leq log(M⋆/M⊙)≤10.6(M_{\star}/M_{\odot}) \leq 10.6 probed by our sample. Using FiBY data, we construct a set of intrinsic SED templates which incorporate both detailed star formation and chemical abundance histories, and a variety of stellar population synthesis (SPS) model assumptions. With this set of intrinsic SEDs, we present a novel approach for directly recovering the shape and normalization of the dust attenuation curve. We find, across all of the intrinsic templates considered, that the average attenuation curve for star-forming galaxies at z≃3.5z\simeq3.5 is similar in shape to the commonly-adopted Calzetti starburst law, with an average total-to-selective attenuation ratio of RV=4.18±0.29R_{V}=4.18\pm0.29. We show that the optical attenuation (AVA_V) versus stellar mass (M⋆M_{\star}) relation predicted using our method is consistent with recent ALMA observations of galaxies at 2<z<32<z<3 in the \emph{Hubble} \emph{Ultra} \emph{Deep} \emph{Field} (HUDF), as well as empirical AV−M⋆A_V - M_{\star} relations predicted by a Calzetti-like law. Our results, combined with other literature data, suggest that the AV−M⋆A_V - M_{\star} relation does not evolve over the redshift range 0<z<50<z<5, at least for galaxies with log(M⋆/M⊙)≳9.5(M_{\star}/M_{\odot}) \gtrsim 9.5. Finally, we present tentative evidence which suggests that the attenuation curve may become steeper at log(M⋆/M⊙)≲9.0(M_{\star}/M_{\odot}) \lesssim 9.0.Comment: 16 pages, 12 figures, accepted for publication in MNRA

    The VANDELS survey: Dust attenuation in star-forming galaxies at z=3−4\mathbf{z=3-4}

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    We present the results of a new study of dust attenuation at redshifts 3<z<43 < z < 4 based on a sample of 236236 star-forming galaxies from the VANDELS spectroscopic survey. Motivated by results from the First Billion Years (FiBY) simulation project, we argue that the intrinsic spectral energy distributions (SEDs) of star-forming galaxies at these redshifts have a self-similar shape across the mass range 8.2≤8.2 \leq log(M⋆/M⊙)≤10.6(M_{\star}/M_{\odot}) \leq 10.6 probed by our sample. Using FiBY data, we construct a set of intrinsic SED templates which incorporate both detailed star formation and chemical abundance histories, and a variety of stellar population synthesis (SPS) model assumptions. With this set of intrinsic SEDs, we present a novel approach for directly recovering the shape and normalization of the dust attenuation curve. We find, across all of the intrinsic templates considered, that the average attenuation curve for star-forming galaxies at z≃3.5z\simeq3.5 is similar in shape to the commonly-adopted Calzetti starburst law, with an average total-to-selective attenuation ratio of RV=4.18±0.29R_{V}=4.18\pm0.29. We show that the optical attenuation (AVA_V) versus stellar mass (M⋆M_{\star}) relation predicted using our method is consistent with recent ALMA observations of galaxies at 2<z<32<z<3 in the \emph{Hubble} \emph{Ultra} \emph{Deep} \emph{Field} (HUDF), as well as empirical AV−M⋆A_V - M_{\star} relations predicted by a Calzetti-like law. Our results, combined with other literature data, suggest that the AV−M⋆A_V - M_{\star} relation does not evolve over the redshift range 0<z<50<z<5, at least for galaxies with log(M⋆/M⊙)≳9.5(M_{\star}/M_{\odot}) \gtrsim 9.5. Finally, we present tentative evidence which suggests that the attenuation curve may become steeper at log(M⋆/M⊙)≲9.0(M_{\star}/M_{\odot}) \lesssim 9.0.Comment: 16 pages, 12 figures, accepted for publication in MNRA
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