1,721,015 research outputs found
Evaluating an adaptation: rice-sediment trade-offs in the Vietnamese Mekong Delta
No full textThe exceptional vulnerability of river deltas to climate change and development pressures means there is an urgent need to implement systemic adaptation actions. One of the most important cases is the Vietnamese Mekong Delta (VMD). This thesis performs a novel application of a system dynamics methodology to evaluate the VMD’s dyke network as a hard adaptation to changes in the region’s hydrological conditions. In doing so it makes a methodological and case study contribution to an emerging research body on the evaluation of adaptation action. Policy analysis and stakeholder consultation are first performed to elucidate the drivers behind the policy to heighten the VMD’s dyke network. A farmer survey is then executed within the rice-growing community in order to quantify the socioeconomic impacts of the adaptation. Finally, a system dynamics model is built to explore the dynamics controlling the impacts of the adaptation and the efficacy of alternative policies for the local agricultural system. A key original theme running through this thesis is its consideration of the socioeconomic role of fluvial sediment in the system.The principle finding, on which both the model and survey agree, is that the switch to high dyke compartments in the VMD(the adaptation) is exacerbating the divide between land-rich and land-poor farmers through the promotion of triple-cropping and sediment exclusion. Factors including the loss of free sediment-bound nutrients for fertilisation, and increasing fertilisation demands, reduce the resilience of poorer farmers to increasing and unpredictable fertiliser prices. The policy currently recommended by the provincial governments to encourage sediment accretion and mitigate the rate of relative sea-level rise is to advocate triennial inundation of paddies. The data presented herein suggest such a policy is sub-optimal,further increasing the risk of debt for smaller-scale farming operations. The testing of various different success criteria weightings did, however, suggest that the less rigid policy of allowing sporadic floodplain inundation and sediment deposition during intense flooding events is preferable to most stakeholder groups
Evaluating sustainable adaptation strategies for vulnerable mega-deltas using system dynamics modelling: rice agriculture in the Mekong Delta’s An Giang Province, Vietnam
No full textAbstractChallenging dynamics are unfolding in social-ecological systems around the globe as society attempts to mitigate and adapt to climate change while sustaining rapid local development. The IPCC's 5th assessment suggests these changing systems are susceptible to unforeseen and dangerous ‘emergent risks’. An archetypal example is the Vietnamese Mekong Delta (VMD) where the river dyke network has been heightened and extended over the last decade with the dual objectives of (1) adapting the delta's 18 million inhabitants and their livelihoods to increasingly intense river-flooding, and (2) developing rice production through a shift from double to triple-cropping. Negative impacts have been associated with this shift, particularly in relation to its exclusion of fluvial sediment deposition from the floodplain. A deficit in our understanding of the dynamics of the rice-sediment system, which involve unintuitive delays, feedbacks, and tipping points, is addressed here, using a system dynamics (SD) approach to inform sustainable adaptation strategies. Specifically, we develop and test a new SD model which simulates the dynamics between the farmers' economic system and their rice agriculture operations, and uniquely, integrates the role of fluvial sediment deposition within their dyke compartment.We use the model to explore a range of alternative rice cultivation strategies. Our results suggest that the current dominant strategy (triple-cropping) is only optimal for wealthier groups within society and over the short-term (ca. 10years post-implementation). The model suggests that the policy of opening sluice gates and leaving paddies fallow during high-flood years, in order to encourage natural sediment deposition and the nutrient replenishment it supplies, is both a more equitable and a more sustainable policy. But, even with this approach, diminished supplies of sediment-bound nutrients and the consequent need to compensate with artificial fertilisers will mean that smaller-scale farmers in the VMD are more vulnerable to accruing debt
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Impulsivity and emotion dysregulation in borderline personality disorder
No full textThis study examined the association of borderline personality disorder (BPD) and negative emotional states with impulsivity in the laboratory. Undergraduate participants who were high in BPD features (high-BPD; n = 39) and controls who were low in BPD features (low-BPD; n = 56) completed measures of negative emotional state before a laboratory measure of impulsivity—a passive avoidance learning task. Controlling for psychopathology, high-BPD participants committed a greater number of impulsive responses than did low-BPD participants. Negative emotional state moderated the effect of BPD on impulsive responses. High-BPD participants who were in a negative emotional state committed fewer impulsive responses than high-BPD participants who were low in negative emotional state. Fear, nervousness, and shame negatively correlated with impulsivity among high-BPD participants but not among low-BPD participants. In addition, high-BPD participants reported greater emotion dysregulation in a variety of domains, compared with low-BPD participant
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Adaptation and development trade-offs: fluvial sediment deposition and the sustainability of rice-cropping in An Giang Province, Mekong Delta
No full textDeltas around the globe are facing a multitude of intensifying environmental change and development-linked pressures. One key concern is the reduction in the quantity of suspended sediment reaching and building floodplains. Sediment deposition provides multiple services to deltaic social-ecological systems, in particular, countering the subsidence of the delta-body, and providing plentiful nutrients. Experiencing particularly rapid change is the Vietnamese Mekong Delta (VMD). In An Giang Province an increasing number of high dyke rings, which exclude the flood and facilitate triple rice-cropping, simultaneously prevent much of the sediment load from reaching the floodplain. This paper explores the trade-offs implicit in the decision to shift from (i) doublecropping (higher sediment deposition) to (ii) triple cropping (lower sediment deposition) by asking: what is the impact of the shift on VMD farmers? Is it sustainable? And what is the significance of the associated sediment exclusion? A novel survey of An Giang rice farmers was conducted, investigating key agricultural practices, and uniquely, the farmers’ estimates of annual sediment deposition depth. The survey elicits some key changes under the adapted system (ii), particularly, unsustainable trajectories in the yield to fertiliser ratio which penalise land-poor farmers. Furthermore, the value (to farmers) of the sediment contribution to agricultural fertilisation which is lost due to triple-cropping is estimated at USD 15 (±5) million annually. We argue that our growing understanding of the importance of sediment in the deltaic social-ecological system may be revealing an emergent risk; arising from conflicting long and short-term adaptation and agricultural development objectives
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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