Payments for Watershed Services: An Application to Irrigation Pricing in the El Angel Watershed, Carchi, Ecuador

Water scarcity is increasingly viewed as the principal constraint limiting agricultural production and human livelihood improvement in the rural areas of many developing countries. Policies that encourage more efficient and equitable water use - including the introduction of incentive-based water pricing systems - are an important challenge. This paper reports the results of a mathematical programming model which was constructed for the El Angel watershed in northern Ecuador with the goal of exploring the effects of several water pricing alternatives. The model incorporates farmers' crop and pasture planting and resource allocation decisions, based on maximizing regional gross margin subject to land, water, labor, seasonal, food security and other constraints. Four water pricing scenarios are examined. The results show that adequate water resources currently exist to permit a reallocation of water within the watershed, which would generate higher regional production and incomes. Several water pricing alternatives are explored which would discipline water use in those parts of the watershed where water is currently overused and unregulated. Incomes could be significantly increased in currently waterscarce parts of the watershed while generating only small reductions in production and incomes in water-abundant zones. While tradeoffs exist among economic, environmental and employment goals, significant net gains are achievable. If a differentiated system of water prices is considered to be unrealistic, a system of single seasonal prices would likely generate reduced, though significant, benefits. Introducing a system of comprehensive water charges would likely create similar benefits in other developing country watersheds facing similar resource constraints.Resource /Energy Economics and Policy,

Effect of hydrofracking fluid on colloid transport in the unsaturated zone

Hydraulic fracturing is expanding rapidly in the US to meet increasing energy demand and requires high volumes of hydrofracking fluid to displace natural gas from shale. Accidental spills and deliberate land application of hydrofracking fluids, which return to the surface during hydrofracking, are common causes of environmental contamination. Since the chemistry of hydrofracking fluids favors transport of colloids and mineral particles through rock cracks, it may also facilitate transport of in situ colloids and associated pollutants in unsaturated soils. We investigated this by subsequently injecting deionized water and flowback fluid at increasing flow rates into unsaturated sand columns containing colloids. Colloid retention and mobilization was measured in the column effluent and visualized in situ with bright field microscopy. While <5% of initial colloids were released by flushing with deionized water, 32–36% were released by flushing with flowback fluid in two distinct breakthrough peaks. These peaks resulted from 1) surface tension reduction and steric repulsion and 2) slow kinetic disaggregation of colloid flocs. Increasing the flow rate of the flowback fluid mobilized an additional 36% of colloids, due to the expansion of water filled pore space. This study suggests that hydrofracking fluid may also indirectly contaminate groundwater by remobilizing existing colloidal pollutants

The effects of a 25% discount on fruits and vegetables: results of a randomized trial in a three-dimensional web-based supermarket

<p>Abstract</p> <p>Background</p> <p>Lowering the price of fruit and vegetables is a promising strategy in stimulating the purchase of those foods. However, the true effects of this strategy are not well studied and it is unclear how the money saved is spent. The aim of this study is to examine the effects of a 25% discount on fruits and vegetables on food purchases in a supermarket environment.</p> <p>Methods</p> <p>A randomized controlled trial with two research conditions was conducted: a control condition with regular prices (n = 52) and an experimental condition with a 25% discount on fruits and vegetables (n = 63). The experiment was carried out using a three-dimensional web-based supermarket, which is a software application in the image of a real supermarket. Data were collected in 2010 in the Netherlands. Participants received a fixed budget and were asked to buy weekly household groceries at the web-based supermarket. Differences in fruit and vegetable purchases, differences in expenditures in other food categories and differences in total calories were analyzed using independent samples t-tests and multiple linear regression models accounting for potential effect modifiers and confounders.</p> <p>Results</p> <p>The purchased amount of fruit plus vegetables was significantly higher in the experimental condition compared to the control condition (Δ984 g per household per week, <it>p </it>= .03) after appropriate adjustments. This corresponds to a 25% difference compared to the control group. Both groups had similar expenditures in unhealthier food categories, including desserts, soda, crisps, candy and chocolate. Furthermore, both groups purchased an equal number of food items and an equal amount of calories, indicating that participants in the discount condition did not spend the money they saved from the discounts on other foods than fruits and vegetables.</p> <p>Conclusion</p> <p>A 25% discount on fruits and vegetables was effective in stimulating purchases of those products and did neither lead to higher expenditures in unhealthier food categories nor to higher total calories purchased. Future studies in real supermarkets need to confirm these findings.</p

Pore scale consideration in unstable gravity driven finger flow

To explain the dynamic behavior of the matric potential at the wetting front of gravity driven fingers, we take into account the pressure across the interface that is not continuous and depends on the radius of the meniscus, which is a function of pore size and the dynamic contact angle θ[subscript d] • θ[subscript d] depends on a number of factors including velocity of the water and can be found by the Hoffman-Jiang equation that was modified for gravity effects. By assuming that water at the wetting front imbibes one pore at a time, realistic velocities are obtained that can explain the capillary pressures observed in unstable flow experiments in wettable and water repellent sands.Keywords: overshoot, fingered flow, dynamic pressure, column flow, preferential flow, dynamic contact angl

Stakeholder views on taxation of sugar-sweetened beverages and its adoption in the Netherlands

An increasing number of governments worldwide have introduced a tax on sugar-sweetened beverages (SSB) for public health. However, the adoption of such a policy is still debated in many other countries, such as in the Netherlands. We investigated Dutch stakeholder views on taxation of SSB and perceived barriers and facilitators to its adoption in the Netherlands. Semi-structured interviews were conducted in 2019 with 27 stakeholders from health and consumer organizations, health professional associations, trade associations, academia, advisory bodies, ministries and parliamentary parties. Data were analysed using a thematic content approach. The findings reveal that, between and within sectors, stakeholders expressed contradictory views on the effectiveness, appropriateness and (socio)economic effects of an SSB tax. Perceived barriers to the adoption of an SSB tax in the Netherlands included an unfavourable political context, limited advocacy for an SSB tax, a strong lobby against an SSB tax, perceived public opposition, administrative load and difficulties in defining SSB. Perceived facilitators to its adoption included an increasing prevalence of overweight, disappointing results from voluntary industry actions, a change of government, state budget deficits, a shift in public opinion, international recommendations and a solid legal basis. In conclusion, this study shows that several challenges remain to be overcome for the adoption of an SSB tax in the Netherlands. Similar research on stakeholder views in other countries may further inform SSB tax policy processes

The effects of a controlled worksite environmental intervention on determinants of dietary behavior and self-reported fruit, vegetable and fat intake

BACKGROUND: Eating patterns in Western industrialized countries are characterized by a high energy intake and an overconsumption of (saturated) fat, cholesterol, sugar and salt. Many chronic diseases are associated with unhealthy eating patterns. On the other hand, a healthy diet (low saturated fat intake and high fruit and vegetable intake) has been found important in the prevention of health problems, such as cancer and cardio-vascular disease (CVD). The worksite seems an ideal intervention setting to influence dietary behavior. The purpose of this study is to present the effects of a worksite environmental intervention on fruit, vegetable and fat intake and determinants of behavior. METHODS: A controlled trial that included two different governmental companies (n = 515): one intervention and one control company. Outcome measurements (short-fat list and fruit and vegetable questionnaire) took place at baseline and 3 and 12 months after baseline. The relatively modest environmental intervention consisted of product information to facilitate healthier food choices (i.e., the caloric (kcal) value of foods in groups of products was translated into the number of minutes to perform a certain (occupational) activity to burn these calories). RESULTS: Significant changes in psychosocial determinants of dietary behavior were found; subjects at the intervention worksite perceived more social support from their colleagues in eating less fat. But also counter intuitive effects were found: at 12 months the attitude and self-efficacy towards eating less fat became less positive in the intervention group. No effects were found on self-reported fat, fruit and vegetable intake. CONCLUSION: This environmental intervention was modestly effective in changing behavioral determinant towards eating less fat (social support, self-efficacy and attitude), but ineffective in positively changing actual fat, fruit and vegetable intake of office workers

Immune dynamics in SARS-CoV-2 experienced immunosuppressed rheumatoid arthritis or multiple sclerosis patients vaccinated with mRNA-1273

BACKGROUND: Patients affected by different types of autoimmune diseases, including common conditions such as multiple sclerosis (MS) and rheumatoid arthritis (RA), are often treated with immunosuppressants to suppress disease activity. It is not fully understood how the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific humoral and cellular immunity induced by infection and/or upon vaccination is affected by immunosuppressants. METHODS: The dynamics of cellular immune reactivation upon vaccination of SARS-CoV-2 experienced MS patients treated with the humanized anti-CD20 monoclonal antibody ocrelizumab (OCR) and RA patients treated with methotrexate (MTX) monotherapy were analyzed at great depth via high-dimensional flow cytometry of whole blood samples upon vaccination with the SARS-CoV-2 mRNA-1273 (Moderna) vaccine. Longitudinal B and T cell immune responses were compared to SARS-CoV-2 experienced healthy controls (HCs) before and 7 days after the first and second vaccination. RESULTS: OCR-treated MS patients exhibit a preserved recall response of CD8(+) T central memory cells following first vaccination compared to HCs and a similar CD4(+) circulating T follicular helper 1 and T helper 1 dynamics, whereas humoral and B cell responses were strongly impaired resulting in absence of SARS-CoV-2-specific humoral immunity. MTX treatment significantly delayed antibody levels and B reactivation following the first vaccination, including sustained inhibition of overall reactivation marker dynamics of the responding CD4(+) and CD8(+) T cells. CONCLUSIONS: Together, these findings indicate that SARS-CoV-2 experienced MS-OCR patients may still benefit from vaccination by inducing a broad CD8(+) T cell response which has been associated with milder disease outcome. The delayed vaccine-induced IgG kinetics in RA-MTX patients indicate an increased risk after the first vaccination, which might require additional shielding or alternative strategies such as treatment interruptions in vulnerable patients. FUNDING: This research project was supported by ZonMw (The Netherlands Organization for Health Research and Development, #10430072010007), the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement (#792532 and #860003), the European Commission (SUPPORT-E, #101015756) and by PPOC (#20_21 L2506), the NHMRC Leadership Investigator Grant (#1173871)