Safeguarding Agricultural Heritage: The Case of Colombia´s Coffee Cultural Landscape

The Coffee Cultural Landscape of Colombia exemplifies the historical, cultural, economic, ecological, and symbolic heritage values of an agricultural landscape. Its inscription as a World Heritage Site elucidates the complexity of safeguarding traditional agro-ecological systems of production threatened by changes in land use, urbanization, farming techniques, and environmental change. Coffee has been the quintessential crop sustaining rural livelihood in Colombia and a main driver behind the country´s development. It is a national symbol, and an internationally recognized high-value commodity. The Coffee Cultural Landscape has the ideal environmental conditions and knowledge to continue producing some of the best coffee in the world; however, the cultural and ecological values of traditional farming practices have yet to be articulated and incorporated into the site´s management. This study proposes a framework for assessing the heritage values of small-scale farms in the Cultural Landscape based on conditions, adjacencies, and connectivity. It considers three different scales for understanding agricultural areas as their function and public benefits change in relation to their surrounding context. Articulating the cultural and ecological values of cultivated lands should serve as a platform for fostering stewardship and responsibility, and for creating incentives and constraints to ensure the continuity and vitality of the Coffee Cultural Landscape

Energetic and Socioeconomic Justification for Solar-Powered Desalination Technology for Rural Indian Villages

This paper provides justification for solar-powered electrodialysis desalination systems for rural Indian villages. It is estimated that 11% of India’s 800 million people living in rural areas do not have access to an improved water source. If the source’s quality in regards to biological, chemical, or physical contaminants is also considered, this percentage is even higher. User interviews conducted by the authors and in literature reveal that users judge the quality of their water source based on its aesthetic quality (taste, odor, and temperature). Seventy-three percent of Indian villages rely on groundwater as their primary drinking supply. However, saline groundwater underlies approximately 60% of the land area in India. Desalination is necessary in order to improve the aesthetics of this water (by reducing salinity below the taste threshold) and remove contaminants that cause health risks. Both technical and socioeconomic factors were considered to identify the critical design requirements for inland water desalination in India. An off-grid power system is among those requirements due to the lack of grid access or intermittent supply, problems faced by half of Indian villages. The same regions in India that have high groundwater salinity also have the advantage of high solar potential, making solar a primary candidate. Within the salinity range of groundwater found in inland India, electrodialysis would substantially reduce the energy consumption to desalinate compared to reverse osmosis, which is the standard technology used for village-level systems. This energy savings leads to a smaller solar array required for electrodialysis systems, translating to reduced capital costs.Massachusetts Institute of Technology. Tata Center for Technology and DesignMassachusetts Institute of Technology. Undergraduate Research Opportunities Progra

Village-Scale Electrodialysis Desalination: Field Trial Validation

This paper presents the design and initial testing of a villagescale photovoltaic (PV) powered electrodialysis reversal (EDR) desalination system for rural India. The system was built by the authors and tested at the Brackish Groundwater National Desalination Research Facility in New Mexico. EDR has the potential to be more cost effective than currently installed village-scale reverse osmosis (RO) systems in offgrid locations due to the lower specific energy consumption of EDR versus RO at high recovery ratios. Lower energetic demand leads to lower solar power system costs for off-grid areas. The system tested in this study is designed to validate that energetic, product water quality, and water recovery requirements can be met. An analytical model of the system that accounts for the composition of natural groundwater is presented and compared to initial experimental results. Additionally, results from the USAID Desal Prize are presented showing the system's performance in regards to recovery ratio and product water quality. This paper presents the design methodology, resulting system parameters, and experimental results for an initial village-scale PV-EDR field trial.Jain Irrigation Systems Ltd.Massachusetts Institute of Technology. Tata Center for Technology and DesignMassachusetts Institute of Technology. Undergraduate Research Opportunities Progra

Sympathetic nervous regulation of calcium and action potential alternans in the intact heart

Rationale: Arrhythmogenic cardiac alternans are thought to be an important determinant for the initiation of ventricular fibrillation. There is limited information on the effects of sympathetic nerve stimulation (SNS) on alternans in the intact heart and the conclusions of existing studies, focused on investigating electrical alternans, are conflicted. Meanwhile, several lines of evidence implicate instabilities in Ca handling, not electrical restitution, as the primary mechanism underpinning alternans. Despite this, there have been no studies on Ca alternans and SNS in the intact heart. The present study sought to address this, by application of voltage and Ca optical mapping for the simultaneous study of APD and Ca alternans in the intact guinea pig heart during direct SNS. Objective: To determine the effects of SNS on APD and Ca alternans in the intact guinea pig heart and to examine the mechanism(s) by which the effects of SNS are mediated. Methods and Results: Studies utilized simultaneous voltage and Ca optical mapping in isolated guinea pig hearts with intact innervation. Alternans were induced using a rapid dynamic pacing protocol. SNS was associated with rate-independent shortening of action potential duration (APD) and the suppression of APD and Ca alternans, as indicated by a shift in the alternans threshold to faster pacing rates. Qualitatively similar results were observed with exogenous noradrenaline perfusion. In co ntrast with previous reports, both SNS and noradrenaline acted to flatten the slope of the electrical restitution curve. Pharmacological block of the slow delayed rectifying potassium current (I Ks ), sufficient to abolish I Ks -mediated APD-adaptation, partially reversed the effects of SNS on pacing-induced alternans. Treatment with cyclopiazonic acid, an inhibitor of the sarco(endo)plasmic reticulum ATPase, had opposite effects to that of SNS, acting to increase susceptibility to alternans, and suggesting that accelerated Ca reuptake into the sarcoplasmic reticulum is a major mechanism by which SNS suppresses alternans in the guinea pig heart. Conclusions: SNS suppresses calcium and action potential alternans in the intact guinea pig heart by an action mediated through accelerated Ca handling and via increased I Ks

ENERGY REQUIREMENT OF ALTERNATIVE TECHNOLOGIES FOR DESALINATING GROUNDWATER FOR IRRIGATION

Increased global water demand coupled with limited water resources has led to acute water shortage in many regions, significantly affecting a griculture, which is the world’s largest consumer of water. Groundwater resources are thus increasingly being used to meet irrigation requirements. However, groundwater resources around the world tend to be saline ( 0.5 ≤ S ≤ 5 g/kg ) rquiring desalination before use. Furthermore, with decreasing water availability, demands for producing permeate from the feed at higher recoveries (>85%) is also increasing. In this work, a thermodynamic least work analysis for desalination and pumping ground water is developed first. Then, the actual energy required by high recovery desalination technologies such as brackish water reverse osmosis (RO), closed circuit reverse osmosis (CCRO) and electrodialysis reversal (EDR) are compared with the thermodynamic least work of desalination from 50-95% recovery. CCRO consumed the least energy until a recovery of 92% after which EDR consumed the least energy. While the energy required for RO and CCRO changed with recovery, EDR energy consumption remained approximately constant at 0.85 kWh/m³. Water table depth was also found to significantly contribute to the total energy consumed, with the power required to pump groundwater being comparable to the desalination power requirements at water table depths greater than 50 m. Thus, the choice of selection of desalination technologies is particularly crucial for water table depths less than 50 m

Feasibility Study of an Electrodialysis System for In-Home Water Desalination and Purification in Urban India

Desalination of high salinity water is an effective way of improving the aesthetic quality of drinking water and has been demonstrated to be a characteristic valued by consumers. Across India, 60% of the groundwater, the primary water source for millions, is brackish or contains a high salt content with total dissolved solids (TDS) ranging from 500 parts per million (ppm) to 3,000ppm. The government does not provide sufficient desalination treatment before the water reaches the tap of a consumer. Therefore consumers have turned to in-home desalination. However, current products are either expensive or have low recovery, product water output per untreated feed water, (∼30%) wasting water resources. Electrodialysis (ED) is a promising technology that desalinates water while maintaining higher recovery (up to 95%) compared to existing consumer reverse osmosis (RO) products. This paper first explores the in-home desalination market to determine critical design requirements for an in-home ED system. A model was then used to evaluate and optimize the performance of an ED stack at this scale and designated salinity range. Additionally, testing was conducted in order to validate the model and demonstrate feasibility. Finally, cost estimates of the proposed in-home ED system and product design concept are presented. The results of this work identified a system design that provides consumers with up to 80% recovery of feed water with cost and size competitive to currently available in-home RO products

Preparation and Characterization of High-Entropy Alloy (TaNb)1−x_{1-x}(ZrHfTi)x_x Superconducting Films

We report on the preparation and the physical properties of superconducting (TaNb)_1-x(ZrHfTi)_x high-entropy alloy films. The films were prepared by means of magnetron sputtering at room temperature, with x ranging from 0 to 1 with an average thickness of 600 - 950 nm. All films crystallize in a pseudo body-centered cubic (BCC) structure. For samples with x < 0.65, the normal-state properties are metallic, while for x > 0.65 the films are weakly insulating. The transition from metallic to weakly insulating occurs right at the near-equimolar stoichiometry. We find all films, except for x = 0 or 1, to become superconducting at low temperatures, and we interpret their superconducting properties within the Bardeen-Cooper-Schrieffer (BCS) framework. The highest transition temperature T_c = 6.9 K of the solid solution is observed for x = 0.43. The highest upper-critical field B_c2(0) = 11.05 T is found for the near-equimolar ratio x = 0.65, where the mixing entropy is the largest. The superconducting parameters derived for all the films from transport measurements are found to be close to those that are reported for amorphous superconductors. Our results indicate that these films of high-entropy alloys are promising candidates for superconducting device fabrication

Effects of a pragmatic lifestyle intervention for reducing body mass in obese adults with obstructive sleep apnoea: a randomised controlled trial

This study investigated the effects of a pragmatic lifestyle intervention in obese adults with continuous positive airway pressure-treated obstructive sleep apnoea hypopnoea syndrome (OSAHS). Sixty patients were randomised 1 : 1 to either a 12-week lifestyle intervention or an advice-only control group. The intervention involved supervised exercise sessions, dietary advice, and the promotion of lifestyle behaviour change using cognitive-behavioural techniques. Outcomes were assessed at baseline (week 0), intervention end-point (week 13), and follow-up (week 26). The primary outcome was 13-week change in body mass. Secondary outcomes included anthropometry, blood-borne biomarkers, exercise capacity, and health-related quality of life. At end-point, the intervention group exhibited small reductions in body mass (−1.8 [−3.0, −0.5] kg; P = 0.007) and body fat percentage (−1 [−2, 0]%; P = 0.044) and moderate improvements in C-reactive protein (−1.3 [−2.4, −0.2] mg·L−1; P = 0.028) and exercise capacity (95 [50, 139] m; P <0.001 ). At follow-up, changes in body mass (−2.0 [−3.5, −0.5] kg; P = 0.010), body fat percentage (−1 [−2, 0]%; P = 0.033), and C-reactive protein (−1.3 [−2.5, −0.1] mg·L−1; P = 0.037 ) were maintained and exercise capacity was further improved (132 [90, 175] m; P <0.001). This trial is registered with ClinicalTrials.gov NCT01546792