916 resultados para Sociology of development
Resumo:
Results of a large-scale survey of resource-poor smallholder cotton farmers in South Africa over three years conclusively show that adopters of Bt cotton have benefited in terms of higher yields, lower pesticide use, less labour for pesticide application and substantially higher gross margins per hectare. These benefits were clearly related to the technology, and not to preferential adoption by farmers who were already highly efficient. The smallest producers are shown to have benefited from adoption of the Bt variety as much as, if not more than, larger producers. Moreover, evidence from hospital records suggests a link between declining pesticide poisonings and adoption of the Bt variety.
Resumo:
Crop production is inherently sensitive to variability in climate. Temperature is a major determinant of the rate of plant development and, under climate change, warmer temperatures that shorten development stages of determinate crops will most probably reduce the yield of a given variety. Earlier crop flowering and maturity have been observed and documented in recent decades, and these are often associated with warmer (spring) temperatures. However, farm management practices have also changed and the attribution of observed changes in phenology to climate change per se is difficult. Increases in atmospheric [CO2] often advance the time of flowering by a few days, but measurements in FACE (free air CO2 enrichment) field-based experiments suggest that elevated [CO2] has little or no effect on the rate of development other than small advances in development associated with a warmer canopy temperature. The rate of development (inverse of the duration from sowing to flowering) is largely determined by responses to temperature and photoperiod, and the effects of temperature and of photoperiod at optimum and suboptimum temperatures can be quantified and predicted. However, responses to temperature, and more particularly photoperiod, at supraoptimal temperature are not well understood. Analysis of a comprehensive data set of time to tassel initiation in maize (Zea mays) with a wide range of photoperiods above and below the optimum suggests that photoperiod modulates the negative effects of temperature above the optimum. A simulation analysis of the effects of prescribed increases in temperature (0-6 degrees C in + 1 degrees C steps) and temperature variability (0% and + 50%) on days to tassel initiation showed that tassel initiation occurs later, and variability was increased, as the temperature exceeds the optimum in models both with and without photoperiod sensitivity. However, the inclusion of photoperiod sensitivity above the optimum temperature resulted in a higher apparent optimum temperature and less variability in the time of tassel initiation. Given the importance of changes in plant development for crop yield under climate change, the effects of photoperiod and temperature on development rates above the optimum temperature clearly merit further research, and some of the knowledge gaps are identified herein.
Resumo:
Development policies in the pastoral areas of Africa assume that pastoralists are poor. Using the Afar pastoralists of Ethiopia as the focus of research this article challenges this depiction of pastoralism by exploring pastoral livelihood goals and traditional strategies for managing risk. Investment in social institutions to minimise the risk of outright destitution, sometimes at the cost of increased poverty, and significant manipulation of local markets enable the Afar to exploit a highly uncertain and marginal environment. Improved development assistance and enhanced targeting of the truly vulnerable within pastoral societies demands an acceptance that pastoral poverty is neither uniform nor universal.
Resumo:
The interest in animal welfare and welfare-friendly food products has been increasing in Europe over the last 10 years. The media, highlighting traditional farming methods and food scares such as those related to salmonella, bovine spongiform encephalopathy/variant Creutzfeldt-Jakob disease (BSE) and avian influenza, have brought the methods of animal farming to public attention. Concerns about farm animal welfare are reflected in the increase in the number of vegetarians and vegans and an increase in consumers wishing to purchase food which is more animal welfare-friendly. This paper considers consumers’ attitudes to animal welfare and to marketing practices, such as product labelling, welfare grading systems and food assurance marks using comparative data collected in a survey of around 1500 consumers in each of Great Britain, Italy and Sweden as part of the EU-funded Welfare Quality research project. The findings suggest a need for the provision of improved consumer information on the welfare provenance of food using appropriate product labelling and other methods.
Resumo:
Poverty is central to the concept of development. However, the relevance given to particular aspects of poverty has changed over the years and with it the manner in which poverty has been represented. The following paper explores how concepts of poverty within the 'poverty discourse' have altered over a 30-year period. A diachronic analysis is performed to explore changes in the topical and thematic composition of the definitions, in addition to the manner in which poverty has been 'framed'. The results illustrated that poverty was variably framed across the decades ranging from a 'neutral' fact to a highly contested state with little agreement over causes and consequences. Nevertheless, the relational analysis revealed the de-problematization of poverty over time. The finding has clear implications for development praxis: poverty needs to be 'attacked', but the root causes, at least from a discursive perspective, may be ignored.
Resumo:
In many river floodplains in the UK, there has been a long history of flood defence, land reclamation and water regime management for farming. In recent years, however, changing European and national policies with respect to farming, environment and flood management are encouraging a re-appraisal of land use in rural areas. In particular, there is scope to develop, through the use of appropriate promotional mechanisms, washland areas, which will simultaneously accommodate winter inundation, support extensive farming methods, deliver environmental benefits, and do this in a way which can underpin the rural economy. This paper explores the likely economic impacts of the development of flood storage and washland creation. In doing so, consideration is given to feasibility of this type of development, the environmental implications for a variety of habitats and species, and the financial and institutional mechanisms required to achieve implementation. (C) 2007 Elsevier Ltd. All rights reserved.
Resumo:
This article examines shock persistence in agricultural and industrial output in India. Drawing on the dual economy literature, the linkages between the sectors through the terms of trade are emphasised. However different dual economy models make differing assumptions regarding the categorisation of variables as being either endogenous or exogenous and this distinction is crucial in explaining the pattern of shock persistence. Using annual data for 1955-95, our results show that shocks to both output series are permanent while those to the terms of trade are transient.
Resumo:
A series of articles, many of them published in this journal, have charted the rapid spread of supermarkets in developing and middle-income countries and forecast its continuation. In this article, the level of supermarket penetration (share of the retail food market) is modelled quantitatively on a cross-section of 42 countries for which data could be obtained, representing all stages of development. GDP per capita, income distribution, urbanisation, female labour force participation and openness to inward foreign investment are all significant explanators. Projections to 2015 suggest significant but not explosive further penetration; increased openness and GDP growth are the most significant factors.
Resumo:
To further our understanding of powdery mildew biology during infection, we undertook a systematic shotgun proteomics analysis of the obligate biotroph Blumeria graminis f. sp. hordei at different stages of development in the host. Moreover we used a proteogenomics approach to feed information into the annotation of the newly sequenced genome. We analyzed and compared the proteomes from three stages of development representing different functions during the plant-dependent vegetative life cycle of this fungus. We identified 441 proteins in ungerminated spores, 775 proteins in epiphytic sporulating hyphae, and 47 proteins from haustoria inside barley leaf epidermal cells and used the data to aid annotation of the B. graminis f. sp. hordei genome. We also compared the differences in the protein complement of these key stages. Although confirming some of the previously reported findings and models derived from the analysis of transcriptome dynamics, our results also suggest that the intracellular haustoria are subject to stress possibly as a result of the plant defense strategy, including the production of reactive oxygen species. In addition, a number of small haustorial proteins with a predicted N-terminal signal peptide for secretion were identified in infected tissues: these represent candidate effector proteins that may play a role in controlling host metabolism and immunity. Molecular & Cellular Proteomics 8: 2368-2381, 2009.
Resumo:
To investigate flower induction in June-bearing strawberry plants, morphological changes in shoot apices and Historic H4 expression in the central zone during flower initiation were observed. Strawberry plants were placed under flower inducible, short-day conditions (23 degrees C/17 degrees C, 10 h day length) for differing number of days (8, 16, 20, 24 or 32 days) and then these plants were transferred to non-inducible, long-day conditions (25 degrees C/20 degrees C, 14 h day length). The shoot apices of plants placed under short-day conditions for 8 days were flat, similar to shoot apices of plants in the vegetative phase of development, and Histone H4 was not expressed in the central zone during the experimental period. On the other hand, the shoot apices of plants placed under short-day conditions for 16 days remained flat, similar to shoot apices of plants placed under short-day conditions for 8 days, but Histone H4 was expressed in the central zone at the end of the short-day treatment. Morphological changes in the shoot apices of these plants were observed 8 days after the change in day-length. These plants developed differentiated flower organs after they were grown for another 30 days under long-day conditions. These results indicate that changes in the expression pattern of the Histone H4 gene occur before morphological changes during flower induction and that the expression of the gene in the central zone can be used as one of the indicators of the flowering process in strawberries. (c) 2006 Elsevier B.V. All rights reserved.
Resumo:
To further our understanding of powdery mildew biology during infection, we undertook a systematic shotgun proteomics analysis of the obligate biotroph Blumeria graminis f. sp. hordei at different stages of development in the host. Moreover we used a proteogenomics approach to feed information into the annotation of the newly sequenced genome. We analyzed and compared the proteomes from three stages of development representing different functions during the plant-dependent vegetative life cycle of this fungus. We identified 441 proteins in ungerminated spores, 775 proteins in epiphytic sporulating hyphae, and 47 proteins from haustoria inside barley leaf epidermal cells and used the data to aid annotation of the B. graminis f. sp. hordei genome. We also compared the differences in the protein complement of these key stages. Although confirming some of the previously reported findings and models derived from the analysis of transcriptome dynamics, our results also suggest that the intracellular haustoria are subject to stress possibly as a result of the plant defense strategy, including the production of reactive oxygen species. In addition, a number of small haustorial proteins with a predicted N-terminal signal peptide for secretion were identified in infected tissues: these represent candidate effector proteins that may play a role in controlling host metabolism and immunity. Molecular & Cellular Proteomics 8: 2368-2381, 2009.
Resumo:
Senescence of plant organs is a genetically controlled process that regulates cell death to facilitate nutrient recovery and recycling, and frequently precedes, or is concomitant with, ripening of reproductive structures. In Arabidopsis thaliana, the seeds are contained within a silique, which is itself a photosynthetic organ in the early stages of development and undergoes a programme of senescence prior to dehiscence. A transcriptional analysis of the silique wall was undertaken to identify changes in gene expression during senescence and to correlate these events with ultrastructural changes. The study revealed that the most highly up-regulated genes in senescing silique wall tissues encoded seed storage proteins, and the significance of this finding is discussed. Global transcription profiles of senescing siliques were compared with those from senescing Arabidopsis leaf or petal tissues using microarray datasets and metabolic pathway analysis software (MapMan). In all three tissues, members of NAC and WRKY transcription factor families were up-regulated, but components of the shikimate and cell-wall biosynthetic pathways were down-regulated during senescence. Expression of genes encoding ethylene biosynthesis and action showed more similarity between senescing siliques and petals than between senescing siliques and leaves. Genes involved in autophagy were highly expressed in the late stages of death of all plant tissues studied, but not always during the preceding remobilization phase of senescence. Analyses showed that, during senescence, silique wall tissues exhibited more transcriptional features in common with petals than with leaves. The shared and distinct regulatory events associated with senescence in the three organs are evaluated and discussed.
Resumo:
The incidence of obesity has reached alarming levels worldwide, thus increasing the risk of development of metabolic disorders (e.g. type 2 diabetes, coronary heart disease (CHD) and cancer). Among the causes of obesity, diet and lifestyle play a central role. Although the treatment of obesity may appear quite straightforward, by simply re-addressing the balance between energy intake and energy expenditure, practically it has been very challenging. In the search for new therapeutic targets for treatment of obesity and related disorders, the gut microbiota and its activities have been investigated in relation to obesity. The human gut microbiota has already been shown to influence total energy intake and lipid metabolism, particularly through colonic fermentation of undigestible dietary constituents and production of short chain fatty acids (SCFA). Recent studies have highlighted the contribution of the gut microbiota to mammalian metabolism and energy harvested from the diet. A dietary modulation of the gut microbiota and its metabolic output could positively influence host metabolism and, therefore, constitute a potential coadjutant approach in the management of obesity and weight loss.
Resumo:
Diverticular disease (DD) is an age-related disorder of the large bowel which may affect half of the population over the age of 65 in the UK. This high prevalence ranks it as one of the most common bowel disorders in western nations. The majority of patients remain asymptomatic but there are associated life-threatening co-morbidities, which, given the large numbers of people with DD, translates into a considerable number of deaths per annum. Despite this public health burden, relatively little seems to be known about either the mechanisms of development or causality. In the 1970s, a model of DD formulated the concept that diverticula occur as a consequence of pressureinduced damage to the colon wall amongst those with a low intake of dietary fiber. In this review, we have examined the evidence regarding the influence of ageing, diet, inflammation and genetics on DD development. We argue that the evidence supporting the barotrauma hypothesis is largely anecdotal. We have also identified several gaps in the knowledge base which need to be filled before we can complete
Resumo:
Dynamic relationships between technologies and organizations are investigated through research on digital visualization technologies and their use in the construction sector. Theoretical work highlights mutual adaptation between technologies and organizations but does not explain instances of sustained, sudden, or increasing maladaptation. By focusing on the technological field, I draw attention to hierarchical structuring around inter-dependent levels of technology; technological priorities of diverse groups; power asymmetries and disjunctures between contexts of development and use. For complex technologies, such as digital technologies, I argue these field-level features explain why organizations peripheral to the field may experience difficulty using emerging technology.