72 research outputs found

    User-centred design of a digital advisory service: enhancing public agricultural extension for sustainable intensification in Tanzania

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    Sustainable intensification (SI) is promoted as a rural development paradigm for sub-Saharan Africa. Achieving SI requires smallholder farmers to have access to information that is context-specific, increases their decision-making capacities, and adapts to changing environments. Current extension services often struggle to address these needs. New mobile phone-based services can help. In order to enhance the public extension service in Tanzania, we created a digital service that addresses smallholder farmers’ different information needs for implementing SI. Using a co-design methodology – User-Centered Design – we elicited feedback from farmers and extension agents in Tanzania to create a new digital information service, called Ushauri. This automated hotline gives farmers access to a set of pre-recorded messages. Additionally, farmers can ask questions in a mailbox. Extension agents then listen to these questions through an online platform, where they record and send replies via automated push-calls. A test with 97 farmers in Tanzania showed that farmers actively engaged with the service to access agricultural advice. Extension agents were able to answer questions with reduced workload compared to conventional communication channels. This study illustrates how User-Centered Design can be used to develop information services for complex and resource-restricted smallholder farming contexts

    Robotized spraying of prefabricated panels

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    A robotic manufacturing cell of pre-fabricated glass reinforced cement panels for construction industry has been developed by DISAM for the Spanish construction company Dragados, SA. The main contribution of the developed system is the automatic programming and control of the whole plan. The architect's 3D-drawing of the building facade done on a CAD system serves as input. From the CAD design, the optimum facade to panels partition is obtained. In order to manufacture each panel, automatic task and path planning are performed for the equipment present in the manufacturing cell: spraying robot, PLCs, control computer, etcThis work was supported by the construction company Dragados, S.A. and the Spanish Ministry of Industry under project PAUTA 1691/91. The authors thank A. Garcia, E. Pinto, 1. Florez, E. Marquez, C. Corpas, 1. Arauzo and A. Cases, and the staff of the Caracola factory in Torrejon de Ardoz (Madrid). Thanks are also due to Christian Schafer for his assistance with the final manuscript.Publicad

    Dark Matter, Light Stops and Electroweak Baryogenesis

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    We examine the neutralino relic density in the presence of a light top squark, such as the one required for the realization of the electroweak baryogenesis mechanism, within the minimal supersymmetric standard model. We show that there are three clearly distinguishable regions of parameter space, where the relic density is consistent with WMAP and other cosmological data. These regions are characterized by annihilation cross sections mediated by either light Higgs bosons, Z bosons, or by the co-annihilation with the lightest stop. Tevatron collider experiments can test the presence of the light stop in most of the parameter space. In the co-annihilation region, however, the mass difference between the light stop and the lightest neutralino varies between 15 and 30 GeV, presenting an interesting challenge for stop searches at hadron colliders. We present the prospects for direct detection of dark matter, which provides a complementary way of testing this scenario. We also derive the required structure of the high energy soft supersymmetry breaking mass parameters where the neutralino is a dark matter candidate and the stop spectrum is consistent with electroweak baryogenesis and the present bounds on the lightest Higgs mass.Comment: 24 pages, 8 figures; version published in Phys.Rev.

    Flavour physics constraints in the BMSSM

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    We study the implications of the presence of the two leading-order, non-renormalizable operators in the Higgs sector of the MSSM to flavour physics observables. We identify the constraints of flavour physics on the parameters of the BMSSM when we: a) focus on a region of parameters for which electroweak baryogenesis is feasible, b) use a CMSSM-like parametrization, and c) consider the case of a generic NUHM-type model. We find significant differences as compared to the standard MSSM case.Comment: 22 pages, 7 figure

    The Light Stop Scenario from Gauge Mediation

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    In this paper we embed the light stop scenario, a MSSM framework which explains the baryon asymmetry of the universe through a strong first order electroweak phase transition, in a top-down approach. The required low energy spectrum consists in the light SM-like Higgs, the right-handed stop, the gauginos and the Higgsinos while the remaining scalars are heavy. This spectrum is naturally driven by renormalization group evolution starting from a heavy scalar spectrum at high energies. The latter is obtained through a supersymmetry-breaking mix of gauge mediation, which provides the scalars masses by new gauge interactions, and gravity mediation, which generates gaugino and Higgsino masses. This supersymmetry breaking also explains the \mu\ and B_\mu\ parameters necessary for electroweak breaking and predicts small tri-linear mixing terms A_t in agreement with electroweak baryogenesis requirements. The minimal embedding predicts a Higgs mass around its experimental lower bound and by a small extension higher masses m_H\lesssim 127 GeV can be accommodated.Comment: 20 pages, 3 figures; v2: changes in the conventions; v3: more details on the Higgs mass prediction, version published in JHE

    Reconfigurable spin-wave propagation in magnetic stripe domains in hybrid system

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    Resumen del trabajo presentado a la INTERMAG Conference - IEEE International Magnetics, celebrada on-line del 26 al 30 de abril de 2021.Very recently magnetic stripe domains, characterized by alternating up and down out-of-plane orientation of the magnetization, have received great interest due to the possibility to use stripe patterns to manipulate spin-wave (SW) propagation as in artificial magnonic crystals. In this work, we demonstrate the control of the SW propagation by using reconfigurable regular stripe-pattern domain structure in the hybrid system. The investigated system consists of 64-nm-thick NdCo layer and 10-nm-thick NiFe layer, coupled through an Al layer of different thicknesses. Magnetic force microscopy (MFM) measurements show that, due to the perpendicular magnetic anisotropy of the NdCo film, the system develops stripe domains aligned with the last in-plane saturation direction. The domain pattern is found to have a period of about 140 nm, which is almost independent on the thickness of the Al layer. The magnetization reversal of the trilayer system was investigated by vibrating sample magnetometer, showing that the hysteresis loop is characterized by a two-step process, due to the different coercivity of the NiFe and NdCo films. Detailed analysis of the hysteresis loops along with micromagnetic simulations indicates that the stray magnetic field coming from the NdCo layer induces a regular domain structure also in the NiFe layer, which is tuned by the thickness of Al spacer. In addition, upon reversing the applied magnetic field, an antiparallel state, characterized by an antiparallel alignment of the magnetization component parallel to the domain axis in the NdCo and NiFe stripes, is formed. Then, Brillouin light scattering spectroscopy has been used to measure the spectra of the SWs propagating in the direction perpendicular to stripe domains for the parallel and the antiparallel state. For both configurations, the dispersion relation shows a strongly nonreciprocal mode. However, in the parallel state SWs propagating with positive and negative wavevector are both characterized by a positive dispersion, while in the reversed state SWs propagating with negative wavevector show a negative dispersion. The above experimental results have been satisfactorily reproduced by numerical simulations. The latter show that the detected SW mode is mainly localized in the NiFe layer and its frequency nonreciprocity can be ascribed to the static magnetization configuration as well as to the interaction with the NdCo induced by the SWs via the dynamic stray field.PID2019-104604RBPeer reviewe

    Fine mapping and conditional analysis identify a new mutation in the autoimmunity susceptibility gene BLK that leads to reduced half-life of the BLK protein

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    OBJECTIVES: To perform fine mapping of the autoimmunity susceptibility gene BLK and identify functional variants involved in systemic lupus erythematosus (SLE). METHODS: Genotyping of 1163 European SLE patients and 1482 controls and imputation were performed covering the BLK gene with 158 single-nucleotide polymorphisms. Logistic regression analysis was done using PLINK and conditional analyses using GENABEL's test score. Transfections of BLK constructs on HEK293 cells containing the novel mutation or the wild type form were analysed for their effect on protein half-life using a protein stability assay, cycloheximide and western blot. CHiP-qPCR for detection of nuclear factor κ B (NFkB) binding. RESULTS: Fine mapping of BLK identified two independent genetic effects with functional consequences: one represented by two tightly linked associated haplotype blocks significantly enriched for NFκB-binding sites and numerous putative regulatory variants whose risk alleles correlated with low BLK mRNA levels. Binding of NFkBp50 and p65 to an associated 1.2 Kb haplotype segment was confirmed. A second independent genetic effect was represented by an Ala71Thr, low-frequency missense substitution with an OR=2.31 (95% CI 1.38 to 3.86). The 71Thr decreased BLK protein half-life. CONCLUSIONS: These results show that rare and common regulatory variants in BLK are involved in disease susceptibility and both, albeit independently, lead to reduced levels of BLK protein

    Decoupling property of the supersymmetric Higgs sector with four doublets

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    In supersymmetric standard models with multi Higgs doublet fields, selfcoupling constants in the Higgs potential come only from the D-terms at the tree level. We investigate the decoupling property of additional two heavier Higgs doublet fields in the supersymmetric standard model with four Higgs doublets. In particular, we study how they can modify the predictions on the quantities well predicted in the minimal supersymmetric standard model (MSSM), when the extra doublet fields are rather heavy to be measured at collider experiments. The B-term mixing between these extra heavy Higgs bosons and the relatively light MSSM-like Higgs bosons can significantly change the predictions in the MSSM such as on the masses of MSSM-like Higgs bosons as well as the mixing angle for the two light CP-even scalar states. We first give formulae for deviations in the observables of the MSSM in the decoupling region for the extra two doublet fields. We then examine possible deviations in the Higgs sector numerically, and discuss their phenomenological implications.Comment: 26 pages, 24 figures, text sligtly modified,version to appear in Journal of High Energy Physic

    A phase I randomized therapeutic MVA-B vaccination improves the magnitude and quality of the T cell immune responses in HIV-1-infected subjects on HAART

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    Trial Design Previous studies suggested that poxvirus-based vaccines might be instrumental in the therapeutic HIV field. A phase I clinical trial was conducted in HIV-1-infected patients on highly active antiretroviral therapy (HAART), with CD4 T cell counts above 450 cells/mm3 and undetectable viremia. Thirty participants were randomized (2:1) to receive either 3 intramuscular injections of MVA-B vaccine (coding for clade B HIV-1 Env, Gag, Pol and Nef antigens) or placebo, followed by interruption of HAART. Methods The magnitude, breadth, quality and phenotype of the HIV-1-specific T cell response were assayed by intracellular cytokine staining (ICS) in 22 volunteers pre- and post-vaccination. Results MVA-B vaccine induced newly detected HIV-1-specific CD4 T cell responses and expanded pre-existing responses (mostly against Gag, Pol and Nef antigens) that were high in magnitude, broadly directed and showed an enhanced polyfunctionality with a T effector memory (TEM) phenotype, while maintaining the magnitude and quality of the pre-existing HIV-1- specific CD8 T cell responses. In addition, vaccination also triggered preferential CD8+ T cell polyfunctional responses to the MVA vector antigens that increase in magnitude after two and three booster doses
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