698 research outputs found

    Fermi Surface Reconstruction in CeRh1−x_{1-x}Cox_{x}In5_{5}

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    The evolution of the Fermi surface of CeRh1−x_{1-x}Cox_xIn5_5 was studied as a function of Co concentration xx via measurements of the de Haas-van Alphen effect. By measuring the angular dependence of quantum oscillation frequencies, we identify a Fermi surface sheet with ff-electron character which undergoes an abrupt change in topology as xx is varied. Surprisingly, this reconstruction does not occur at the quantum critical concentration xcx_c, where antiferromagnetism is suppressed to T=0. Instead we establish that this sudden change occurs well below xcx_c, at the concentration x ~ 0.4 where long range magnetic order alters its character and superconductivity appears. Across all concentrations, the cyclotron effective mass of this sheet does not diverge, suggesting that critical behavior is not exhibited equally on all parts of the Fermi surface.Comment: 4 pages, 4 figure

    Do ecosystem service maps and models meet stakeholders’ needs? A preliminary survey across sub-Saharan Africa

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    To achieve sustainability goals, it is important to incorporate ecosystem service (ES) information into decision-making processes. However, little is known about the correspondence between the needs of ES information users and the data provided by the researcher community. We surveyed stakeholders within sub-Saharan Africa, determining their ES data requirements using a targeted sampling strategy. Of those respondents utilising ES information (>90%; n=60), 27% report having sufficient data; with the remainder requiring additional data – particularly at higher spatial resolutions and at multiple points in time. The majority of respondents focus on provisioning and regulating services, particularly food and fresh water supply (both 58%) and climate regulation (49%). Their focus is generally at national scales or below and in accordance with data availability. Among the stakeholders surveyed, we performed a follow-up assessment for a sub-sample of 17 technical experts. The technical experts are unanimous that ES models must be able to incorporate scenarios, and most agree that ES models should be at least 90% accurate. However, relatively coarse-resolution (1–10 km2) models are sufficient for many services. To maximise the impact of future research, dynamic, multi-scale datasets on ES must be delivered alongside capacity-building efforts

    Substance abuse and intimate partner violence: treatment considerations

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    Given the increased use of marital- and family-based treatments as part of treatment for alcoholism and other drug disorders, providers are increasingly faced with the challenge of addressing intimate partner violence among their patients and their intimate partners. Yet, effective options for clinicians who confront this issue are extremely limited. While the typical response of providers is to refer these cases to some form of batterers' treatment, three fundamental concerns make this strategy problematic: (1) most of the agencies that provide batterers' treatment only accept individuals who are legally mandated to complete their programs; (2) among programs that do accept nonmandated patients, most substance-abusing patients do not accept such referrals or drop out early in the treatment process; and (3) available evidence suggests these programs may not be effective in reducing intimate partner violence. Given these very significant concerns with the current referral approach, coupled with the high incidence of IPV among individuals entering substance abuse treatment, providers need to develop strategies for addressing IPV that can be incorporated and integrated into their base intervention packages

    A continental-scale validation of ecosystem service models

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    Faced with environmental degradation, governments worldwide are developing policies to safeguard ecosystem services (ES). Many ES models exist to support these policies, but they are generally poorly validated, especially at large scales, which undermines their credibility. To address this gap, we describe a study of multiple models of five ES, which we validate at an unprecedented scale against 1675 data points across sub-Saharan Africa. We find that potential ES (biophysical supply of carbon and water) are reasonably well predicted by the existing models. These potential ES models can also be used as inputs to new models for realised ES (use of charcoal, firewood, grazing resources and water), by adding information on human population density. We find that increasing model complexity can improve estimates of both potential and realised ES, suggesting that developing more detailed models of ES will be beneficial. Furthermore, in 85% of cases, human population density alone was as good or a better predictor of realised ES than ES models, suggesting that it is demand, rather than supply that is predominantly determining current patterns of ES use. Our study demonstrates the feasibility of ES model validation, even in data-deficient locations such as sub-Saharan Africa. Our work also shows the clear need for more work on the demand side of ES models, and the importance of model validation in providing a stronger base to support policies which seek to achieve sustainable development in support of human well-being

    Medically Biodegradable Hydrogenated Amorphous Silicon Microspheres

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    [EN] Hydrogenated amorphous silicon colloids of low surface area (<5 m(2)/g) are shown to exhibit complete in-vitro biodegradation into orthosilicic acid within 10-15 days at 37 degrees C. When converted into polycrystalline silicon colloids, by high temperature annealing in an inert atmosphere, microparticle solubility is dramatically reduced. The data suggests that amorphous silicon does not require nanoscale porosification for full in-vivo biodegradability. This has significant implications for using a-Si:H coatings for medical implants in general, and orthopedic implants in particular. The high sphericity and biodegradability of submicron particles may also confer advantages with regards to contrast agents for medical imaging.This work has been partially supported by the Spanish CICyT projects, FIS2009-07812, Consolider CSD2007-046, MAT2009-010350 and PROMETEO/2010/043.Shabir, Q.; Pokale, A.; Loni, A.; Johnson, DR.; Canham, L.; Fenollosa Esteve, R.; Tymczenko, MK.... (2011). Medically Biodegradable Hydrogenated Amorphous Silicon Microspheres. Silicon. 3(4):173-176. https://doi.org/10.1007/s12633-011-9097-4S17317634Salonen J, Kaukonen AM, Hirvonen J, Lehto VP (2008) J Pharmaceutics 97:632–53Anglin EJ, Cheng L, Freeman WR, Sailor MJ (2008) Adv Drug Deliv Rev 60:1266–77O’Farrell N, Houlton A, Horrocks BR (2006) Int J Nanomedicine 1:451–72Canham LT (1995) Adv Mater 7:1037, PCT patent WO 97/06101,1999Park JH, Gui L, Malzahn G, Ruoslahti E, Bhatia SN, Sailor MJ (2009) Nature Mater 8:331–6Cullis AG, Canham LT, Calcott PDJ (1997) J Appl Phys 82:909–66Canham LT, Reeves CR (1996) Mat Res Soc Symp 414:189–90Edell DJ, Toi VV, McNeil VM, Clark LD (1992) IEEE Trans Biomed Eng 39:635–43Fenollosa R, Meseguer F, Tymczenko M (2008) Adv Mater 20:95Fenollosa R, Meseguer F, Tymczenko M, Spanish Patent P200701681, 2007Pell LE, Schricker AD, Mikulec FV, Korgel BA (2004) Langmuir 20:6546Xifré-Perez E, Fenollosa R, Meseguer F (2011) Opt Express 19:3455–63Fenollosa R, Ramiro-Manzano F, Tymczenko M, Meseguer F (2010) J Mater Chem 20:5210Xifré-Pérez E, Domenech JD, Fenollosa R, Muñoz P, Capmany J, Meseguer F (2011) Opt Express 19–4:3185–92Rodriguez I, Fenollosa R, Meseguer F, Cosmetics & Toiletries 2010;42–49Ramiro-Manzano F, Fenollosa R, Xifré-Pérez E, Garín M, Meseguer F (2011) Adv Mater 23:3022–3025. doi: 10.1002/adma.201100986Iler RK (1979) Chemistry of silica: solubility, polymerization, colloid & surface properties & biochemistry. Wiley, New YorkTanaka K, Maruyama E, Shimado T, Okamoto H (1999) Amorphous silicon. Wiley, New York, NYPatterson AL (1939) Phys Rev 56:978–82Canham LT, Reeves CL, King DO, Branfield PJ, Gabb JG, Ward MC (1996) Adv Mater 8:850–2Iler RK In: Chemistry of silica: solubility, polymerization, colloid & surface properties &Biochemistry. Wiley, New York, NYFinnie KS, Waller DJ, Perret FL, Krause-Heuer AM, Lin HQ, Hanna JV, Barbe CJ (2009) J Sol-Gel Technol 49:12–8Zhao D, Huo Q, Feng J, Chmelka BF, Stucky GD (1998) J Am Chem Soc 120:6024–36Fan D, Akkaraju GR, Couch EF, Canham LT, Coffer JL (2010) Nanoscale 1:354–61Tasciotti E, Godin B, Martinez JO, Chiappini C, Bhavane R, Liu X, Ferrari M (2011) Mol Imaging 10:56–

    Solubilization of Proteins in 2DE: An Outline

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    Protein solubilization for two-dimensional electrophoresis (2DE) has to break molecular interactions to separate the biological contents of the material of interest into isolated and intact polypeptides. This must be carried out in conditions compatible with the first dimension of 2DE, namely isoelectric focusing. In addition, the extraction process must enable easy removal of any nonprotein component interfering with the isoelectric focusing. The constraints brought in this process by the peculiar features of isoelectric focusing are discussed, as well as their consequences in terms of possible solutions and limits for the solubilization process
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