3,655 research outputs found

    Farming systems and Conservation Agriculture: Technology, structures and agency in Malawi

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    Conservation Agriculture (CA) is advocated as an agricultural innovation that will improve smallholder famer resilience to future climate change. Under the conditions presented by the El Niño event of 2015/16, the implementation of CA was examined in southern Malawi at household, district and national institutional levels. Agricultural system constraints experienced by farming households are identified, and in response the technologies, structures and agency associated with CA are evaluated. The most significant constraints were linked to household health, with associated labour and monetary impacts, in addition to the availability of external inputs of fertiliser and improved seed varieties. Our findings show that such constraints are not adequately addressed through current agricultural system support structures, with the institutions surrounding CA (in both Government extension services and NGO agricultural projects) focusing attention predominantly at field level practice, rather than on broader system constraints such as education and health support systems. Limited capacity within local institutions undermines long term efforts to implement new technologies such as CA. It is vitally important that the flexibility of farmers to adapt new technologies in a locally-appropriate manner is not closed down through national and institutional aims to build consensus around narrow technical definitions of a climate-smart technology such as CA. To enable farmers to fully utilise CA programmes, interventions must take a more holistic, cross-sectoral approach, understanding and adapting to address locally experienced constraints. Building capacity within households to adopt new agricultural practices is critical, and integrating healthcare support into agricultural policy is a vital step towards increasing smallholder resilience to future climate change

    Modelling acidification, recovery and target loads for headwater catchments in Nova Scotia, Canada

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    The response of twenty acid-sensitive headwater catchments in Nova Scotia to acidic deposition was investigated for the period 1850&ndash;2100 using a dynamic hydrochemical model (MAGIC: Model of Acidification of Groundwater in Catchments). To ensure robust model simulation, MAGIC was calibrated to the long-term chemical trend in annual lake observations (13&ndash;20 years). Model simulations indicated that the surface waters of all twenty catchments acidified to the 1970s but showed subsequent recovery (increases in acid neutralising capacity (ANC) and pH) as sulphate deposition decreased. However, under proposed future emissions reductions (approximately 50% of current deposition) simulated ANC and pH will not return to estimated pre-industrial levels by 2100. An ANC of 20 &mu;mol<sub>c</sub> L<sup>&minus;1</sup> and pH of 5.4 were defined as acceptable chemical thresholds (or critical chemical limits) for aquatic organisms in the current study. Under the proposed emissions reductions only one catchment is predicted to remain below the critical limit for ANC by 2100; three additional catchments are predicted to remain below the critical limit for pH. Dynamic models may be used to estimate target loads, i.e., the required deposition reductions to achieve recovery within a given time. Setting target loads at approximately 30% of current depositions would allow three of the four lakes to reach the chemical criteria by 2030. In contrast to the generally good prognosis for surface waters, soils lost an average of 32% of estimated initial base saturation and recovery is estimated to be very slow, averaging 23% lower than pre-acidification levels in 2100

    Intrinsic point defects in off stoichiometric Cu2ZnSnSe4 A neutron diffraction study

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    This work is an experimental study of intrinsic point defects in off stoichiometric kesterite type CZTSe by means of neutron powder diffraction. We revealed the existence of copper vacancies VCu , various cation anti site defects CuZn, ZnCu, ZnSn, SnZn, and CuZn , as well as interstitials Cui, Zni in a wide range of off stoichiometric polycrystalline powder samples synthesized by the solid state reaction. The results show that the point defects present in off stoichiometric CZTSe agree with the off stoichiometry type model, assuming certain cation substitutions accounting for charge balance. In addition to the known off stoichiometry types A H, new types I L have been introduced. For the very first time, a correlation between the chemical composition of the CZTSe kesterite type phase and the occurring intrinsic point defects is presented. In addition to the offstoichiometry type specific defects, the Cu Zn disorder is always present in the CZTSe phase. In Cu poor Zn rich CZTSe, a composition considered as the one that delivers the best photovoltaic performance, mainly copper vacancies, ZnCu and ZnSn anti sites are present. Also, this compositional region shows the lowest degree of Cu Zn disorde

    Partial Photoionization Cross Sections And Photoelectron Angular Distributions For Double Excitations Up To The N=5 Threshold In Helium

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    Partial photoionization cross sections sigma(n) and photoelectron angular distributions beta(n) were measured for all possible final ionic states He+(n) in the region of the double excitations N(K,T)(A) up to the N=5 threshold. At a photon energy bandpass of 12 meV below the thresholds N=3,4, and 5, this level of differentiation offers the most critical assessment of the dynamics of the two-electron excitations to date. The experimental data are very well described by the most advanced theoretical calculations. Weaker double-excitation series with K=N-4 are clearly visible in the beta(n) data, and even previously unobserved extremely weak series members with A=-1 can be discerned, showing the high sensitivity of the angular resolved measurements. The shapes of the resonance-induced variations of sigma(n) or beta(n) in the double excitations below a given threshold N change radically depending on the final ionic state n but display striking similarities when comparing the satellite states with n=N-1 and n=N-2 below each threshold N. These systematic patterns may indicate a general rule for the underlying two-electron dynamics

    Supporting 'design for reuse' with modular design

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    Engineering design reuse refers to the utilization of any knowledge gained from the design activity to support future design. As such, engineering design reuse approaches are concerned with the support, exploration, and enhancement of design knowledge prior, during, and after a design activity. Modular design is a product structuring principle whereby products are developed with distinct modules for rapid product development, efficient upgrades, and possible reuse (of the physical modules). The benefits of modular design center on a greater capacity for structuring component parts to better manage the relation between market requirements and the designed product. This study explores the capabilities of modular design principles to provide improved support for the engineering design reuse concept. The correlations between modular design and 'reuse' are highlighted, with the aim of identifying its potential to aid the little-supported process of design for reuse. In fulfilment of this objective the authors not only identify the requirements of design for reuse, but also propose how modular design principles can be extended to support design for reuse

    An Introduction to Quantum Programming in Quipper

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    Quipper is a recently developed programming language for expressing quantum computations. This paper gives a brief tutorial introduction to the language, through a demonstration of how to make use of some of its key features. We illustrate many of Quipper's language features by developing a few well known examples of Quantum computation, including quantum teleportation, the quantum Fourier transform, and a quantum circuit for addition.Comment: 15 pages, RC201

    Nature as a 'Lifeline': The Power of Photography when Exploring the Experiences of Older Adults living with Memory Loss and Memory Concerns.

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    The visual is an underutilised modality through which to investigate experiences of memory loss in older people. We describe a visual ethnography with older adults experiencing subjective or objective memory loss, receiving a cognitive wellbeing group intervention designed to prevent cognitive decline and dementia (APPLE-Tree programme). We aimed to explore lived experiences of people with memory concerns, how participants engaged with this photography and co-design project, and how collaboration with an artist/photographer enhanced this process. Nineteen participants shared photographs reflecting what they valued in their daily lives, their experiences of memory concerns, and the intervention. Fourteen participated in qualitative photo-elicitation interviews, and thirteen collaborated with a professional artist/photographer to co-create an exhibition, in individual meetings and workshops, during which a researcher took ethnographic field notes. Eight participants were re-interviewed after the exhibition launch. We contextualise images produced by participants in relation to discourses around the visual and ageing and highlight their relationship with themes developed through thematic analysis that interconnects photographic, observational and interview data. We present themes around the use of photographs to: (1) celebrate connections to nature as a lifeline; (2) anchor lives within the context of relationships with family; (3) reflect on self and identity, enduring through ageing, memory concerns, pandemic, and ageing stereotypes. We explore visual research as a powerful tool for eliciting meaningful accounts from older adults experiencing cognitive change and to connect the arts and social sciences within ageing studies

    High-Resolution Electron Time-of-Flight Apparatus for the Soft-X-Ray Region

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    A gas-phase time-of-flight (TOF) apparatus, capable of supporting as many as six electron-TOF analyzers viewing the same interaction region, has been developed to measure energy- and angle-resolved electrons with kinetic energies up to 5 keV. Each analyzer includes a newly designed lens system that can retard electrons to about 2% of their initial kinetic energy without significant loss of transmission; the analyzers can thus achieve a resolving power (E/ΔE) greater than 104 over a wide kinetic-energy range. Such high resolving power is comparable to the photon energy resolution of state-of-the-art synchrotron–radiation beamlines in the soft x-ray range, opening the TOF technique to numerous high-resolution applications. In addition, the angular placement of the analyzers, by design, permits detailed studies of nondipolar angular distribution effects in gas-phase photoemission

    Density-dependent increase in superpredation linked to food limitation in a recovering population of northern goshawks, Accipiter gentilis

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    We are grateful to R. Lourenço and A.K. Mueller for their helpful comments. We thank Forest Research for funding all fieldwork on goshawks during 1973-1996, Forest Enterprise for funding fieldwork after 1998 and T. Dearnley and N. Geddes for allowing and facilitating work in Kielder Forest. This work was also partly funded by a Natural Environment Research Council studentship NE/J500148/1 to SH and a grant NE/F021402/1 to XL and by Natural Research. We thank I. Yoxall and B. Little for the data they collected and their contributions to this study. Lastly, we thank English Nature and the British Trust for Ornithology for kindly issuing licences to monitor goshawk nest sitesPeer reviewedPostprin

    Angular distributions of the atomic scandium 3d and 4s photoelectrons in the region of the 3p - \u3e 3d giant resonance

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    A determination of the angular distribution parameter beta of the 3d and 4s main lines of atomic scandium in the resonance region of the 3p-- \u3e nd,ms excitations has been carried out using electron spectrometry in conjunction with monochromatized synchrotron radiation., These measurements reveal strong variations of beta8 throughout the entire resonance region, highlighting the complicated nature of the ionization process for this first and seemingly simple 3d transition metal. The beta values-of the photoelectrons resulting in 4s subshell, ionization deviate significantly from 2.0 in qualitative, but not-quantitative, agreement with recent many-body perturbation-theory calculations
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