2,029 research outputs found

    Customer views on service delivery in the Child Support Agency

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    This research was commissioned to investigate further a range of issues identified in the last CSA national client survey carried out in 1995. It is a qualitative study involving in-depth interviews with parents with care and absent parents. The research aimed to identify client satisfaction and dissatisfaction arising specifically from operational or staff activities. The main findings are: Absent parents and parents with care accepted the principle of dual responsibility. Parents with care valued the recognition of the father's responsibilities and regular payments of maintenance. Although absent parents tended to agree with the Agency's aims, some thought they had been incorrectly implemented. The Agency was seen as pursuing 'soft targets' and thought to be ineffective in obtaining maintenance from absent parents who refused to comply. Overall people were left with an impression of an impersonal system consisting of forms, letters and, increasingly, telephone calls. The Agency was seen as lacking even handedness in ensuring that all absent parents paid maintenance. Many parents were dissatisfied with their assessment as they felt it was too high and therefore inaccurate. None of the parents were able to explain fully how their assessment had been calculated and many wanted to know the details of the formula used. There were mixed views on the forms used in the assessment, some found them easy to complete, while for others it was more difficult, but few had tried to use the help notes provided. There was some objection to having to provide information on partners income and the failure to ask about debt. Contact with the Agency was a source of dissatisfaction. Some parents disliked the tone of letters from the CSA, and many complained about delays and not being kept informed of progress. Very few parents in the study had had face-to-face contact with the CSA, but many said it would be their preferred method of contact. Although there were no cases of the absent parent giving up work as a result of involvement with the CSA, some reported no longer working overtime or looking for promotion, as they believed any extra income would go in maintenance payments. For parents with care there was a greater incentive to take employment when maintenance replaced Income Support, but if it was not regularly received, they had to live on a reduced amount of benefit

    CXCR4 expression heterogeneity in neuroblastoma cells due to ligand-independent regulation

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    <p>Abstract</p> <p>Background</p> <p>CXCR4, the receptor for the chemokine stromal-derived factor 1 (SDF-1), has been shown to mediate many of the processes essential for cancer progression such as tumor cell proliferation, metastasis, and angiogenesis. To understand the role of CXCR4 in the biology of neuroblastoma, a disease that presents with wide spread metastases in over 50% of patients, we screened ten patient derived-neuroblastoma cell-lines for basal CXCR4 expression and sought to identify characteristics that correlate with tumor cell phenotype.</p> <p>Results</p> <p>All cell lines expressed <it>CXCR4 </it>mRNA at variable levels, that correlated well with three distinct classes of CXCR4 surface expression (low, moderate, or high) as defined by flow cytometry. Analysis of the kinetics of CXCR4 surface expression on moderate and high expressing cell lines showed a time-dependent down-regulation of the receptor that directly correlated with cell confluency, and was independent of SDF1. Cell lysates showed the presence of multiple CXCR4 isoforms with three major species of approximately 87, 67 and 55 kDa associating with high surface expression, and two distinct species of 45 and 38 kDa correlating with low to null surface expression. Western blot analysis of CXCR4 immunoprecipitates showed that the 87 and 67 kDa forms were ubiquitinated, while the others were not. Finally, treatment of cells with a proteasome inhibitor resulted in down regulation of CXCR4 surface expression.</p> <p>Conclusions</p> <p>Taken together, these data show that regulation of CXCR4 surface expression in neuroblastoma cells can occur independently of SDF-1 contribution arguing against an autocrine mechanism. Additionally these data suggest that post-translational modifications of CXCR4, in part through direct ubiquitination, can influence trafficking of CXCR4 to the surface of neuroblastoma cells in a ligand-independent manner.</p

    D-Branes and Fluxes in Supersymmetric Quantum Mechanics

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    Type 0A string theory in the (2,4k) superconformal minimal model backgrounds, with background ZZ D-branes or R-R fluxes can be formulated non-perturbatively. The branes and fluxes have a description as threshold bound states in an associated one-dimensional quantum mechanics which has a supersymmetric structure, familiar from studies of the generalized KdV system. The relevant bound state wavefunctions in this problem have unusual asymptotics (they are not normalizable in general, and break supersymmetry) which are consistent with the underlying description in terms of open and closed string sectors. The overall organization of the physics is very pleasing: The physics of the closed strings in the background of branes or fluxes is captured by the generalized KdV system and non-perturbative string equations obtained by reduction of that system (the hierarchy of equations found by Dalley, Johnson, Morris and Watterstam). Meanwhile, the bound states wavefunctions, which describe the physics of the ZZ D-brane (or flux) background in interaction with probe FZZT D-branes, are captured by the generalized mKdV system, and non-perturbative string equations obtained by reduction of that system (the Painleve II hierachy found by Periwal and Shevitz in this context).Comment: 41 pages, LaTe

    Effects of Prey Abundance on Breeding Season Diet of Northern Goshawks (\u3cem\u3eAccipiter gentilis\u3c/em\u3e) Within an Unusual Prey Landscape

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    A critical element of diet analysis is species adaptability to alternative prey sources. The breeding-season diet of Northern Goshawks (Accipiter gentilis) includes both mammalian and avian species, varies geographically, and is often dependent upon tree squirrels of the genera Sciurus andTamiasciurus. We studied alternative prey sources of Northern Goshawks in the South Hills of south-central Idaho, an area where tree squirrels are naturally absent and other prey frequently important in the diet of goshawks, such as smaller corvids, are uncommon. We quantified the diet of goshawks using nest cameras and surveyed abundance of prey using line transects. We found that goshawks consumed roughly 18.5% birds and 78.7% mammals by biomass, with diet dominated by the Belding\u27s ground squirrel (Urocitellus beldingi, also known as Spermophilus beldingi; 74.8% of total biomass consumed); however, the percentages of mammals and birds in the diet varied between years. The diet was low in diversity, with high overlap among nests, indicating a strong local dependence on the dominant food item. Lastly, the proportion of mammalian prey in the diet was greater in larger broods than in smaller broods. This study provides new insight into the adaptability of the goshawk, particularly in areas with unique prey assemblages

    Resonant Inelastic X-Ray Scattering at the K Edge of Ge

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    We study the resonant inelastic x-ray scattering (RIXS) at the KK edge of Ge. We measure RIXS spectra with systematically varying momenta in the final state. The spectra are a measure of exciting an electron-hole pair. We find a single peak structure (except the elastic peak) as a function of photon energy, which is nearly independent of final-state momenta. We analyze the experimental data by means of the band structure calculation. The calculation reproduces well the experimental shape, clarifying the implication of the spectral shape.Comment: 17 pages,9 figures, Please also see our related paper: cond-mat/040500

    Predicting Nesting Habitat of Northern Goshawks in Mixed Aspen-Lodgepole Pine Forests in a High-Elevation Shrub-Steppe Dominated Landscape

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    We developed a habitat suitability model for predicting nest locations of breeding Northern Goshawks (Accipiter gentilis) in the high-elevation mixed forest and shrub-steppe habitat of south-central Idaho, USA. We used elevation, slope, aspect, ruggedness, distance-to-water, canopy cover, and individual bands of Landsat imagery as predictors for known nest locations with logistic regression. We found goshawks prefer to nest in gently-sloping, east-facing, non-rugged areas of dense aspen and lodgepole pine forests with low reflectance in green (0.53 - 0.61 ÎŒm) wavelengths during the breeding season. We used the model results to classify our 43,169 hectare study area into nesting suitability categories: well suited (8.8%), marginally suited (5.1%), and poorly suited (86.1%). We evaluated our model’s performance by comparing the modeled results to a set of GPS locations of known nests (n = 15) that were not used to develop the model. Observed nest locations matched model results 93.3% of the time for well suited habitat and fell within poorly suited areas only 6.7% of the time. Our method improves on goshawk nesting models developed previously by others and may be applicable for surveying goshawks in adjacent mountain ranges across the northern Great Basin

    Furthering the understanding of silicate-substitution in α-tricalcium phosphate : an X-ray diffraction, X-ray fluorescence and solid-state nuclear magnetic resonance study

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    High-purity (SupT) and reagent-grade (ST), stoichiometric and silicate-containing α-tricalcium phosphate (α-TCP: ST0/SupT0 and Si-TCP x = 0.10: ST10/SupT10) were prepared by solid-state reaction based on the substitution mechanism Ca3(PO4)(2-x)(SiO4)x. Samples were determined to be phase pure by X-ray diffraction (XRD), and Rietveld analysis performed on the XRD data confirmed inclusion of Si in the α-TCP structure as determined by increases in unit cell parameters; particularly marked increases in the b-axis and ÎČ-angle were observed. X-ray fluorescence (XRF) confirmed the presence of expected levels of Si in Si-TCP compositions as well as significant levels of impurities (Mg, Al and Fe) present in all ST samples; SupT samples showed both expected levels of Si and a high degree of purity. Phosphorus (31P) magic-angle-spinning solid-state nuclear magnetic resonance (MAS NMR) measurements revealed that the high-purity reagents used in the synthesis of SupT0 can resolve the 12 expected peaks in the 31P spectrum of α-TCP compared to the low-purity ST0 that showed significant spectral line broadening; line broadening was also observed with the inclusion of Si which is indicative of induced structural disorder. Silicon (29Si) MAS NMR was also performed on both Si-TCP samples which revealed Q0 species of Si with additional Si Q1/Q2 species that may indicate a potential charge-balancing mechanism involving the inclusion of disilicate groups; additional Q4 Si species were also observed, but only for ST10. Heating and cooling rates were briefly investigated by 31P MAS NMR which showed no significant line broadening other than that associated with the emergence of ÎČ-TCP which was only realised with the reagent-grade sample ST0. This study provides an insight into the structural effects of Si-substitution in α-TCP and could provide a basis for understanding how substitution affects the physicochemical properties of the material

    String Theory and Water Waves

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    We uncover a remarkable role that an infinite hierarchy of non-linear differential equations plays in organizing and connecting certain {hat c}<1 string theories non-perturbatively. We are able to embed the type 0A and 0B (A,A) minimal string theories into this single framework. The string theories arise as special limits of a rich system of equations underpinned by an integrable system known as the dispersive water wave hierarchy. We observe that there are several other string-like limits of the system, and conjecture that some of them are type IIA and IIB (A,D) minimal string backgrounds. We explain how these and several string-like special points arise and are connected. In some cases, the framework endows the theories with a non-perturbative definition for the first time. Notably, we discover that the Painleve IV equation plays a key role in organizing the string theory physics, joining its siblings, Painleve I and II, whose roles have previously been identified in this minimal string context.Comment: 49 pages, 4 figure

    Resonant inelastic x-ray scattering (RIXS) spectra of magnesium diboride

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    Using the tight-binding linear muffin-tin orbitals method, the soft x-ray fluorescence K-emission spectra of boron in MgB_2, excited close to the absorption edge, are estimated. In the calculations the angle of incidence between the direction of the incoming photon and the hexagonal axis of the specimen is 60 degrees and 75 degrees. Comparison with experiment is possible in the former case where good agreement is found. Furthermore, another resonant feature below the Fermi energy is predicted for the larger angle. This feature can be related to the excitations to the antibonding B pi-band in the neighbourhood of the L-H line in the Brillouin zone.Comment: 4 pages with 4 figure

    An angle-resolved soft x-ray spectroscopy study of the electronic states of single crystal MgB2

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    Angle-resolved soft x-ray measurements made at the boron K-edge in single crystal MgB2 provide new insights into the B-2p local partial density of both unoccupied and occupied band states. The strong variation of absorption with incident angle of exciting x-rays permits the clear separation of contributions from \sigma states in the boron plane and \pi states normal to the plane. A careful comparison with theory accurately determines the energy of selected critical kk points in the conduction band. Resonant inelastic x-ray emission at an incident angle of 15 degrees shows a large enhancement of the emission spectra within about 0.5 eV of the Fermi level that is absent at 45 degrees and is much reduced at 60 degrees. We conclude that momentum transferred from the resonant inelastic x-ray scattering (RIXS) process couples empty and filled states across the Fermi level.Comment: Accepted to PRB. 13 pages, 6 figure
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