407,222 research outputs found

    Archetypes of land transformations and trajectories of ecosystem services in mountains. [ID660]

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    Based on a synthesis of 51 cases of temporal changes in land use and ecosystem services within mountain landscapes, we analyze how changes in land-use intensity influence the supply of ten key services and we describe six typical archetypes. Our analysis reveals that land-use intensity is an important factor shaping these archetypes. Land-use intensification often degrades ecosystem services (eg recreation and water regulation), with the exception of services targeted by intensification (food or timber) and with differences between forest and agricultural intensification. Service degradation following intensification is not always reversed by reductions in land-use intensity (extensification)

    Characteristics of feeding and breeding practices for intensification of smallholder dairy systems in the Kenya highlands

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    This study aimed at better understanding of the characteristics of feeding and breeding practices smallholder farmers adopt in intensifying their dairy production. Use of hired labour for fodder gathering, growing of fodder crops and purchase of feeds increased with increasing intensification, but Bos taurus breeds did not respond to increasing feeding intensification while Bos indicus cattle responded, calving at earlier age and yielding more milk. Overall, first calving occurred at 32 months, but days open prolonged to 250 days with milk yield of 4 litres per day of calving interval. A principal component analysis extracted six feeding and breeding components, explaining 71.79% of the total variations in feeding and breeding practices for dairy intensification. The six components were labelled: non- intensified feeding and breeding; breeding decisions based-intensification; high external resource based-intensification; moderate resource based-intensification; resource poor based-intensification; and moderate external resource based-intensification. These characteristics points to some `evolutionary process¿ of intensification involving feeding and breeding decisions, depending on the risk-bearing capacity of the household. Intensification enhancing interventions for smallholders need be considered in the context of the household economy. Interventions on feeding and breeding have to be packaged together holistically if intensification is to enhance productivity. A selective intervention on only one of these is associated with low productivity levels, only contributing to sustaining family subsistence livelihood

    Intensification of oxidation capacity using chloroalkanes as additives in hydrodynamic and acoustic cavitation reactors

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    The effect of the presence and absence of the chloroalkanes, dichloromethane (CH2Cl2), chloroform (CHCl3) and carbon tetrachloride (CCl4) on the extent of oxidation of aqueous I- to I3- has been investigated in (a) a liquid whistle reactor (LWR) generating hydrodynamic cavitation and (b) an ultrasonic probe, which produces acoustic cavitation. The aim has been to examine the intensification achieved in the extent of oxidation due to the generation of additional free radicals/oxidants in the reactor as a result of the presence of chloroalkanes. It has been observed that the extent of increase in the oxidation reaction is strongly dependent on the applied pressure in the case of the LWR. Also, higher volumes of the chloroalkanes favour the intensification and the order of effectiveness is CCl4> CHCl3 > CH2Cl2. However, the results with the ultrasonic probe suggest that an optimum concentration of CH2Cl2 or CHCl3 exists beyond which there is little increase in the extent of observed intensification. For CCl4, however, no such optimum concentration was observed and the extent of increase in the rates of oxidation reaction rose with the amount of CCl4 added. Stage wise addition of the chloroalkanes was found to give marginally better results in the case of the ultrasonic probe as compared to bulk addition at the start of the run. Although CCl4 is the most effective, its toxicity and carcinogenicity may mean that CH2Cl2 and CHCl3 offer a safer viable alternative and the present work should be useful in establishing the amount of chloroalkanes required for obtaining a suitable degree of intensification

    52-week efficacy and safety of telbivudine with conditional tenofovir intensification at week 24 in HBeAg-positive chronic Hepatitis B

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    Background and Aims: The Roadmap concept is a therapeutic framework in chronic hepatitis B for the intensification of nucleoside analogue monotherapy based on early virologic response. The efficacy and safety of this approach applied to telbivudine treatment has not been investigated. Methods: A multinational, phase IV, single-arm open-label study (ClinicalTrials.gov ID NCT00651209) was undertaken in HBeAg-positive, nucleoside-naive adult patients with chronic hepatitis B. Patients received telbivudine (600 mg once-daily) for 24 weeks, after which those with undetectable serum HBV DNA (<300 copies/mL) continued to receive telbivudine alone while those with detectable DNA received telbivudine plus tenofovir (300 mg once-daily). Outcomes were assessed at Week 52. Results: 105 patients commenced telbivudine monotherapy, of whom 100 were included in the efficacy analysis. Fifty-five (55%) had undetectable HBV DNA at Week 24 and continued telbivudine monotherapy; 45 (45%) received tenofovir intensification. At Week 52, the overall proportion of undetectable HBV DNA was 93% (93/100) by last-observation-carried-forward analysis (100% monotherapy group, 84% intensification group) and no virologic breakthroughs had occurred. ALT normalization occurred in 77% (87% monotherapy, 64% intensification), HBeAg clearance in 43% (65% monotherapy, 16% intensification), and HBeAg seroconversion in 39% (62% monotherapy, 11% intensification). Six patients had HBsAg clearance. Myalgia was more common in the monotherapy group (19% versus 7%). No decrease in the mean glomerular filtration rate occurred in either treatment group at Week 52. Conclusions: Telbivudine therapy with tenofovir intensification at Week 24, where indicated by the Roadmap strategy, appears effective and well tolerated for the treatment of chronic hepatitis B. Trial Registration: ClinicalTrials.gov NCT0065120

    Appraisal of the environmental sustainability of milk production systems in New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Science in Life Cycle Management at Massey University, Manawatū, New Zealand

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    Life Cycle Assessment (LCA) plays an important role in the environmental assessment of agricultural product systems, including dairy farming systems. Generally, an LCA study accounts for the comprehensive resource use and environmental emissions associated with the life cycle of a studied product system. The inventoried inputs and outputs are then transformed into different environmental impact categories using science-based environmental cause-effect mechanisms. There are different LCA modelling approaches (e.g. attributional LCA [ALCA] and consequential LCA [CLCA]) that can be used to address different research questions; however, there is currently no consensus on the most appropriate approach and when to use it. These LCA approaches require different types of data and methodological procedures and, therefore, generate different sets of environmental information which may have different implications for decision-making. In the present research, a series of studies utilising different LCA modelling approaches were undertaken of pasture-based dairy farming systems in the Waikato region (the largest dairy region in New Zealand). The purposes of the studies were to: (i) assess the environmental impacts and identify environmental hotspots of current pasture-based dairy farming systems, (ii) compare environmental hotspots between high and low levels of dairy farm intensification, (iii) investigate the environmental impacts of potential alternative farm intensification methods to increase milk productivity, and (iv) assess the environmental impacts of different future intensified dairy farming scenarios. Twelve midpoint impact categories were assessed: Climate Change (CC), Ozone Depletion Potential (ODP), Human Health Toxicity - non-cancer effects (Non-cancer), Human Health Toxicity - cancer effects (Cancer), Particulate Matter (PM), Ionizing Radiation - human health effects (IR), Photochemical Ozone Formation Potential (POFP), Acidification Potential (AP), Terrestrial Eutrophication Potential (TEP), Freshwater Eutrophication Potential (FEP), Marine Eutrophication Potential (MEP) and Ecotoxicity for Aquatic Freshwater (Ecotox). Firstly, the environmental impacts of 53 existing pasture-based dairy farm systems in the Waikato region were assessed using ALCA. The results showed that both the offfarm and on-farm stages made significant contributions to a range of environmental impacts per kg of fat- and protein-corrected milk (FPCM), and the relative contributions of the stages varied across different impact categories. Farms classified as high intensification based on a high level of farm inputs (i.e. stocking rate, level of nitrogen (N) fertiliser and level of brought-in feeds) had higher impact results than low intensification farms for 10 of 12 impact categories. This was driven mainly by the offfarm stage, including production of brought-in feeds, manufacturing of agrichemicals (e.g. fertilisers and pesticides), and transport of off-farm inputs for use on a dairy farm. The exceptions were the environmental indicators PM, POFP, AP and TEP; their results were determined mainly by ammonia emissions from the on-farm activities. Secondly, environmental consequences resulting from meeting a future increase in demand for milk production (i.e. 20% more milk production per hectare relative to that in 2010/11) by using different farm intensification scenarios for dairy farming systems in the Waikato region were assessed using CLCA. In this study, only technologies/flows that were actually affected by use of different intensification options to increase milk production were accounted for. The identified intensification methods were: (i) increased pasture utilisation efficiency, (ii) increased use of N fertiliser to boost on-farm pasture production, and (iii) increased use of brought-in feed (i.e. maize silage). The results showed that improved pasture utilisation efficiency was the most effective intensification option since it resulted in lower environmental impacts than the other two intensification options. The environmental performance between the other two intensification options varied, depending on impact categories (environmental tradeoffs). Thirdly, prospective ALCA was used to assess the environmental impacts of six prospective (future) dairy farming intensification scenarios in the Waikato region, primarily involving increased stocking rate, that were modelled to increase milk production per hectare by 50% in 2025. In this study, prospective (future) average flows that were derived from extrapolation were accounted for. The potential intensification scenarios were: (i) increased animal productivity (increased milk production per cow), (ii) increased use of mixed brought-in feed, (iii) improved pasture utilisation efficiency, (iv) increased use of N fertiliser to boost on-farm pasture production, (v) increased use of brought-in maize silage, and (vi) replacement of total mixed brought-in feed in the second scenario by wheat grain. The results showed that, apart from improved animal productivity which was considered the best option, improved pasture utilisation efficiency was the second environmentally-preferential option compared with other intensification options for pasture-based dairy farming systems in the Waikato region. There were environmental trade-offs between other intensification options. The present research demonstrated that pasture-based dairy farming systems in the Waikato region contribute to a range of environmental impacts. More intensive farming systems not only have increased milk productivity (milk production per hectare) but also increased environmental impacts (per kg FPCM) in most environmental impact categories. Farm intensification options associated with improved farm efficiency (e.g. animal productivity or pasture utilisation efficiency) are promising as they have lower environmental indicator results (per kg FPCM) compared with other intensification methods. Increased use of off-farm inputs (e.g. N fertilisers and brought-in feeds) increases some, and decreases other, environmental indicator results. Therefore, decision-making associated with choice of alternative farm intensification options beyond farm efficiency improvements will require prioritisation between different environmental impacts and/or focusing on the ability of key decision-makers to effect change (for example, by distinguishing between local and global activities contributing to environmental impacts). The present research has shown that different LCA modelling approaches can be used in a sequential manner to maximise the usefulness of environmental assessment. Initially, ALCA (based on current average flows) can be used to identify environmental hotspots in the life cycle of dairy farming systems. This will generate environmental information that can assist in selection of improvement options. Subsequently, the improvement options selected should be evaluated using CLCA (based on marginal flows). This will produce comparative environmental information resulting from implementing the selected improvement options, strategies or policies in relation to a non-implementation scenario, when the wider contribution of co-products is accounted for. Finally, prospective ALCA (based on future average flows) can be used to assess total or net environmental benefits

    Intensification test on maize production in the Sudano-Sahelian zone: techniques, soils, climate and economic conditions. [P28]

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    The global context expects increased food production in the agricultural sector thereby substituting benefits in the petroleum sector and related services i.e. the conservation of biodiversity or carbon sequestration. These objectives are intended to be achieved under the constraint of expected climate change. Progress is particularly hoped for African agriculture, which by its low-intensity practices and low current yields is faced with a substantial margin of progression. The study conducted in two villages (Gashiga and Kawtal) in northern Cameroon during the 2013 farming season aimed to understand the feasibility of maize intensification in the current physical, climatic and economic conditions. Gashiga experienced sporadic rainfall during the 2013 farming season contrary to better rainfall conditions at Kawtal. Two levels of intensification were compared to the peasant practices (NP) consisting of 36 plots of producers with contrasting soil fertility levels, two repetitions conducted per plot. The first level (N1) corresponds to the specifications of the crop currently disseminated. The second level (N2) comprised of more intensive techniques (variety, seed treatments, organo-mineral fertilization and fight against weeds). The test cluster analysis showed increased production for N1 and N2 against NP (respectively 0.8 and 1.9 t.ha-1) of maize grain at Kawtal. Yields for NP and N1 were equivalent at Gashiga and N2 experienced an increase of 1.5 t.ha-1 of maize grain Soil fertility impacted just NP. Factors such as crop density and weed pressure limited the result of intensification. Despite the increased production achieved, both levels of intensification were not profitable. More than climate, economic conditions are a major constraint for crop intensification in North Cameroon. (Résumé d'auteur

    Girl Farm Labour And Double-Shift Schooling In The Gambia: The Paradox Of Development Intervention

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    This article examines the intensification of Gambian girls’ domestic and farm labour contributions as a result of the introduction of double-shift schooling. Drawing on fieldwork among female farmers and their daughters in Brikama the article puts forth the following arguments: double shift schooling facilitates the intensification and increased appropriation of surplus value from girls’ household and farm labour because girls are more readily able to meet gendered labour obligations that are central to the moral economy of the household and to the demands of agrarian production; secondly, double shift schooling highlights the paradoxical nature of development intervention where, on the one hand, legislation and policy call for a reduction in child labour by increasing access to school and, on the other, neo-liberal educational policy serves to facilitate the intensification of girls’ domestic and farm labour. It maintains that the intensification of girls’ work must be placed within a wider context where children’s, particularly girls’ cheap, flexible and/or unremunerated labour is central to the functioning of local and global processes of accumulation.Inequality, Poverty, Labour, Schooling

    Intensified processes for FAME production from waste cooking oil: a technological review

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    This article reviews the intensification of fatty acid methyl esters (FAME) production from waste cooking oil (WCO) using innovative process equipment. In particular, it addresses the intensification of WCO feedstock transformation by transesterification, esterification and hydrolysis reactions. It also discusses catalyst choice and product separation. FAME production can be intensified via the use of a number of process equipment types, including as cavitational reactors, oscillatory baffled reactors, microwave reactors, reactive distillation, static mixers and microstructured reactors. Furthermore, continuous flow equipment that integrate both reaction and separation steps appear to be the best means for intensifying FAME production. Heterogeneous catalysts have also shown to provide attractive results in terms of reaction performance in certain equipment, such as microwave reactors and reactive distillation

    The diurnal nature of future extreme precipitation intensification

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    Short‐duration, high‐impact precipitation events in the extratropics are invariably convective in nature, typically occur during the summer, and are projected to intensify under climate change. The occurrence of convective precipitation is strongly regulated by the diurnal convective cycle, peaking in the late afternoon. Here we perform very high resolution (convection‐permitting) regional climate model simulations to study the scaling of extreme precipitation under climate change across the diurnal cycle. We show that the future intensification of extreme precipitation has a strong diurnal signal and that intraday scaling far in excess of overall scaling, and indeed thermodynamic expectations, is possible. We additionally show that, under a strong climate change scenario, the probability maximum for the occurrence of heavy to extreme precipitation may shift from late afternoon to the overnight/morning period. We further identify the thermodynamic and dynamic mechanisms which modify future extreme environments, explaining both the future scaling's diurnal signal and departure from thermodynamic expectations
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