Solving reaction-diffusion equations 10 times faster

The most popular numerical method for solving systems of reaction-diffusion equations continues to be a low order finite-difference scheme coupled with low order Euler time stepping. This paper extends previous 1D work and reports experiments that show that with high--order methods one can speed up such simulations for 2D and 3D problems by factors of 10--100. A short MATLAB code (2/3D) that can serve as a template is included.\ud \ud This work was supported by the Engineering and Physical Sciences Research Council (UK) and by the MathWorks, Inc

Antidumping Duties in the Agriculture Sector: Trade Restricting or Trade Deflecting

The key issues on the negotiation table in the agriculture sector are the elimination of export subsidies, a progressive reduction of tariffs and reduction in domestic support. However, it is observed that trade liberalization often involves moving from one set of distortions to another rather than a movement to free trade. More specifically, in the case of trade liberalization in manufacturing, countries have replaced lower tariffs with antidumping duties (ADD). Feinberg and Olson (2005) empirically show that countries that agreed to larger tariff reductions under the Uruguay Round are more likely to use AD statutes to protect their domestic industries. Thus if the use of ADD in agriculture are effective as a trade barrier (that is there is little trade diversion) then negotiators might need to include AD reform along-with lower tariffs in their future negotiations. In this paper we analyze whether imposition of an antidumping duty restrict imports of the named commodity or is the supply of imports deflected from countries named in the petition to countries not named in the antidumping petition? We find that AD duties have had a significant impact on the imports of agricultural commodities from countries named on the petition. However, our results also indicate that there was little trade diversion towards countries not named in the AD petition. It seems that AD is a plausible protectionist policy.Agriculture, Antidumping, Trade Effect, US, Protection, International Relations/Trade,

Aquaculture and food security, poverty alleviation and nutrition in Ghana: Case study prepared for the Aquaculture for Food Security, Poverty Alleviation and Nutrition project

This study provides an overview of the aquaculture sector in Ghana. It assesses the actual and potential contribution of aquaculture to poverty reduction and food security, and identifies enabling conditions for and drivers of the development of Ghana’s aquaculture sector. The study uses data collected from a variety of primary and secondary sources, including key informant interviews with actors within the aquaculture sector and relevant secondary literature

Gaining Rights to Citizenship: The Presence of Social Sciences in Agricultural Research and the Global Progress of

This article first presents reflections on the joint work carried out by Michael Cernea and this paper's author over 8-9 years for gaining "room, recognition and resources" within the CGIAR for sociological and socio-anthropological research on farmers, their practices and needs. The status of social research inside the CGIAR has gone through ups and downs in the uphill battle for expanding social research within this organization. Social scientists have constantly worked to feed their findings into the Centers' biophysical research. The paper documents the contribution of Michael Cernea, the first sociologist who acceded to CGIAR's top science and policy bodies, to strengthening the presence and influence of sociological and anthropological knowledge within CGIAR's institutional architecture and scientific products.The second part of this study presents the high promise of Conservation Agriculture (CA) - a new paradigm for non-tillage agricultural production that offers improved productivity and environmental protection. CA principles are universally applicable. The author offers global data on the impressive advances and distribution of CA, which covers already some 125 million ha distributed across all continents and agro-ecologies. CA is a farmer-driven socio-cultural phenomenon which has expanded at a yearly rate of 7 mil. ha during the past decade

Making Sustainable Agriculture Real in CAP 2020: The Role of Conservation Agriculture

Europe is about to redefine its Common Agriculture Policy (CAP) for the near future. The question is whether this redefinition is more a fine-tuning of the existing CAP or whether thorough changes can be expected. Looking back to the last revision of CAP the most notable change is, undoubtedly, the concern about EU and global food security. The revival of the interest in agricultural production already became evident during the Health Check as a consequence of climbing commodity prices in 2007/08. It is therefore no surprise that “rising concerns regarding both EU and global food security” is the first topic to appear in the list of justifications for the need for a CAP reform. Other challenges mentioned in this list such as sustainable management of natural resources, climate change and its mitigation, improvement of competitiveness to withstand globalization and rising price volatility, etc., while not new are considered worthwhile enough to be maintained and reappraised

Potential for conservation agriculture in the dry marginal zone of central Syria: A preliminary assessment

This paper reports on early soil related outcomes from conservation agriculture (CA) benchmark sites located within the marginal rainfed environment of agro-ecological zone 4 (annual rainfall: 200–250 mm) in pre-conflict central Syria. The outcomes reported are specifically those that relate to beneficial soil quality and water retention attributes relative to conventional tillage-based soil management practices applied to the fodder barley–livestock system, the dominant system in the zone. On-farm operational research was established to examine the impact of a barley (Hordeum vulgare) and vetch (Vicia sativa) rotation intercropped with atriplex (Atriplex halimus) and salsola (Salsola collina), under CA and conventional tillage agriculture, on the soil quality parameters and crop productivity. Preliminary results showed that CA had a positive effect on the soil quality parameters and crop performance. The soil moisture and hydraulic conductivity were higher under CA (p < 0.05), combined with improved productivity (grain and above-ground biomass) under specific crop mixes. The results suggest that despite the marginal nature of the zone, the use of CA is a viable option for the future of farmers’ livelihoods within similar localities and agro-climates, given the benefits for soil moisture and grain and straw productivity. In addition, it is likely to positively impact those in marginal environments where both pastoralism and agro-pastoralism production systems co-exist and compete for crop biomass as a main source of livestock feed. The increase in grain and straw yields vis-à-vis improvements in biophysical parameters in the CA system relative to tillage agriculture does suggest, however, that the competition with livestock for biomass is likely to reduce over time, and farmers would be able to return increased levels of straw (as stubble and residue) as mulch, given improved biomass yields

Barriers and Enablers of Water Conservation in Formal Residential Households in Cape Town, South Africa

In recent years, climate change has caused great changes in weather patterns such as extreme changes in rainfall leading to prolonged drought. Rapid urbanization has led to more than half of the world's population living in urban centres, and the growing urban population must share increasing scarcity of water, exacerbated by climate change. Thus, climate change and urbanization has contributed to the emergence of more water-stressed cities. This thesis is concerned with water conservation as a method of adaptation to an urban water crisis. It looks into the water crisis in the City of Cape Town that took place during 2015-2017. The severe water crisis has been attributed to prolonged drought, rapid population growth, reliance on six-rain-fed dams to provide 95% of the city's water supply, and excessively high water use by formal residential households. The City of Cape Town took various measures to manage both the demand and the supply of water in order to alleviate the stress caused by the water scarcity. From January 2016, a public education campaign was paired with progressively increased water restrictions. However, despite the growing water restrictions and the worsening of the water crisis, Capetonians did not reduce water consumption enough. Against this background, this thesis aims at gaining a nuanced understanding of the barriers and enablers to water conservation amongst residents in formal residential households in the City of Cape Town. The study focuses on formal residential households because the residents use 65% of the total municipal water supply. Data collection was carried out primarily in the Southern and Northern suburbs and consisted of in-depth interviews with 44 respondents using a semi-structured interview guide about daily water conservation as well as perceptions of the water crisis and of their role in mitigating the water crisis. The data analysis involved development of a coding system and identification of three categories of water savers amongst the highest, the lowest, and the median levels of water conversation within the data set, referred to as respective the ‘avid', the ‘low' and the ‘moderate' water savers. The key findings are that the main barrier of water conservation for the ‘low water savers' is lack of willingness to inconvenience one-self in relation to water conservation. Other important barriers to water conservation for the ‘low water savers' included lack of information regarding the on-going water crisis, perceptions of the water crisis as non-urgent, limited trust in water governance institutions, and interest in maximising own benefit from the common water resource. The dominant enabler amongst the ‘avid water savers' is the pro-environment identity they possess, combined with a high self-efficacy to make a difference to the water crisis through their actions. The study showed that this dominant enabling factor works as a catalyst to enhance other enabling factors, especially seeking information and engaging in conversations about water conservation within their social networks. Barriers such as the discomfort of taking short showers, standing inside a bucket during a shower and collecting greywater for re-use are seen as necessary actions that align with their identity and altruistic outlook towards the environment. Interestingly, ‘the moderate water savers' held similar proenvironment identity but were constrained, mostly by institutional barriers, to reduce their water use. Thus, the overall argument is that there is not one barrier or one enabler to water conservation. Rather, the main argument is that an overriding enabling factor for increased water conservation in daily life is a pro-environment identity combined with a high sense of self-efficacy. Finally, this study has shown that the factor of Personal Characteristics, serves as the main enabler and as the main barrier to water conservation because Personal Characteristics have a ripple effect on how factors such as Information, Social, Technical, Financial or Institutional factors affect a respondent's water conservation

Considerations of Development in Malaysian Borneo

Given Malaysia’s vast natural resources, the country has embarked on an ambitious set of development projects capitalizing on the opportunities afforded by extractive industrialization. Global and national demand for oil palm products, timber, and hydropower resources coupled with a governmental development agenda guided by neoliberal market principles has led to both economic growth and social and environmental injustice. This chapter argues for an alternative development model along the lines suggested by Escobar in addressing Malaysia’s path to development and fiscal well-being in a manner that safeguards its cultural and natural resources

The potential therapeutic role of selenium in diffuse large B-cell lymphoma

PhDThe clinical background to this work confirms the very poor outcome of patients with recurrent diffuse large B-cell lymphoma (DLBCL) and highlights the need for better therapies. One such potential option would be to add selenium (Se) to conventional chemotherapy. Previous work has demonstrated the ability of non-toxic concentrations of Se to sensitise DLBCL cell lines to chemotherapy and to protect normal cells from chemotherapy-induced toxicity. The aims of this study were therefore to identify mechanisms of Se action and potential biomarkers of Se activity. The form of Se used was methylseleninic acid (MSA), a precursor of methylselenol, which is the metabolite thought to be responsible for the anti-tumour effects of organic Se compounds. DLBCL cell lines differed in their sensitivity to MSA, which may relate to differences in intracellular glutathione depletion by MSA. MSA sensitivity, however, was not related to the induction of DNA damage or to the p53 status of lymphoma cell lines. Although cytotoxic concentrations of MSA induced apoptosis, chemo-sensitising concentrations did not enhance apoptosis or alter pro-apoptotic pathways. MSA induced endoplasmic reticulum (ER) stress in a concentration-dependent manner, however, in an MSA-resistant cell line, this led to autophagy and cell survival. Thus, ER stress induction is not a mechanism of chemo-sensitisation. MSA inhibited HDAC activity in DLBCL cell lines but only in a cell-based assay, suggesting that a metabolite of MSA is responsible for this effect. In addition, MSA inhibited the hypoxia-induced induction of HIF-1α in DLBCL cell lines. Peripheral blood mononuclear cells (PBMCs) were relatively resistant to MSA and this was associated with increased expression of two pro-survival proteins, GRP78 and NF-κB. In addition, the metabolism of MSA differed between PBMCs and DLBCL cell lines, suggesting that methylselenol is formed more efficiently in the latter. In contrast, keratinocytes and fibroblasts were relatively sensitive to MSA, but MSA was unable to protect keratinocytes from the toxicity of chemotherapeutic agents. These results differ 3 from those obtained in DLBCL cell lines in which MSA enhances the activity of chemotherapeutic agents. Combining MSA and bortezomib in mantle cell lymphoma cell lines unexpectedly resulted in an antagonistic interaction. This was associated with the induction of ER stress and autophagy and increased expression of two pro-survival proteins, Bcl-2 and Mcl-1. A proteomics approach identified novel protein changes induced by chemo-sensitising concentrations of MSA in two DLBCL cell lines. Several potential biomarkers of Se activity were identified; GRP78, NF-κB, vascular endothelial growth factor and acetylated histone H3. In conclusion, Se in the form of MSA affects many intracellular pathways in DLBCL cell lines, such that it has not been possible to identify a single unifying mechanism of Se action. However, differences have been observed between PBMCs and DLBCL cell lines and this work has identified novel protein changes and mechanisms of Se actionKatherine Priestly Trust Fund Medical reseach Counci