Sectoral water use responses to droughts and heatwaves: analyses from local to global scales for 1990–2019

Water use for various sectors (e.g. irrigation, livestock, domestic, energy and manufacturing) is increasing due to a growing global population and economic development. Additionally, increases in frequency and severity of droughts, heatwaves and compound drought-heatwave events, also lead to responses in sectoral water use and a reduction in water availability, intensifying water scarcity. However, limited knowledge exists on the responses in sectoral water use during these hydroclimatic extremes. In this study we quantify the impacts of droughts, heatwaves and compound events on water use of irrigation, livestock, domestic, energy and manufacturing sectors at global, country and local scales. To achieve this, datasets of reported and downscaled sectoral water use (i.e. withdrawal and consumption) were evaluated during these hydroclimatic extremes and compared to normal (non-extreme) periods for 1990–2019. Our analysis shows that these hydroclimatic extremes affect water use patterns differently per sector and region. Reported data show that domestic and irrigation water use increases during heatwaves in Eastern Europe and central continental United States, while water use decreases for thermoelectric sector, particularly in Europe while it increases in north and Eastern Asia. Additionally, global water use response patterns reveal that irrigation and domestic sectors are mostly prioritized over livestock, thermoelectric and manufacturing. Reported local-scale data reveal that for most sectors and regions/locations, stronger water use responses are found for heatwaves and compound events compared to impacts during hydrological droughts. Our outcomes provide improved understanding of sectoral water use behaviour under hydroclimatic extremes. Nonetheless, given the future threats to water availability and the limited accessible information of water use, there is an urgency to collect more monitored-driven data of sectoral water use for improved assessments of water scarcity under these extremes. Consequently, this research reveals the necessity of more realistic water use models to better represent the sectoral responses to hydroclimatic extremes

Energy Recovery from a Zipline Braking System via Regenerative Braking using Buck-Boost Converter

This paper provides the study on the design, construction, and testing of a Regenerative Braking prototype, for zipline rides, that recovers energy upon its activation. The authors of this study wanted to address the energy crisis issue by providing other means for energy generation, which is the innovation of Regenerative Brake. The design of the prototype depends on the operating parameters of the chosen zipline ride. The elements used in the prototype are: geared dc motors, each coupled to the roller of the trolley; capacitors; Buck-Boost converter; and a lead-acid battery. The prototype works by having geared dc motors convert the kinetic energy from the rider to electrical energy. The generated electricity goes through the buck-boost converter to regulate the resulting voltage. This is done to meet the voltage requirement of the lead-acid battery before storing the regulated electricity. After recording the needed data, the resulting currents and battery charging times are averaged to help determine the energy generated. Resulting data showed it would take roughly two years to charge the 4Ah lead acid battery using the prototype for this study. Despite the minimal result, the prototype is proven to be capable of recovering energy from the zipline braking system. This implies that this study can now be an option for energy generation, instead of always resorting to construction of renewable- and coal-fired power plants

National identity predicts public health support during a global pandemic (vol 13, 517, 2022) : National identity predicts public health support during a global pandemic (Nature Communications, (2022), 13, 1, (517), 10.1038/s41467-021-27668-9)

Publisher Copyright: © The Author(s) 2022.In this article the author name ‘Agustin Ibanez’ was incorrectly written as ‘Augustin Ibanez’. The original article has been corrected.Peer reviewe

Economic analysis of prawn (Penaeus monodon) culture in the Philippines, II: Grow-out operations

The dramatic fall in prawn (Penaeus monodon) prices coupled with environmental concerns has resulted in a relative stagnation of prawn grow-out operations in the Philippines. Leaders of the Philippine aquaculture sector are concerned that their cost of production is higher than that of their close competitors in Indonesia and Thailand. Also, the environmental and production crash experienced in Taiwan has led to a general perception that intensive culture cannot be sustained. The sector recently experienced a lack of direction and growth, combined with crowded water sheds, excessive use of water bodies, overuse of groundwater and continued destruction of mangrove. A field survey of prawn growers was conducted in August-October 1992 using a standardized economic questionnaire that included costs, returns and growers perceptions of constraints. Economic estimates were developed for representative production systems; intensive, semi-intensive, extensive and prawn-milkfish rotation. The incentive to expand the prawn pond area is not strong. Existing intensive facilities can be operated efficiently and profitably, but new intensive operations will most likely need to include water treatment capabilities for water entering and exiting grow-out ponds. Canals, reservoirs or ponds used for water quality improvement may be able to concurrently produce a profitable crop, such as milkfish-prawn rotation. Internal rate of return for semi-intensive ponds using earthen ponds was higher than for other culture systems. If, over time, water quality and conservation constraints are sufficiently addressed, stocking densities might be increased. Research and extension programs targeting equity should focus on integrated systems

Economic analysis of prawn (Penaeus monodon) culture in the Philippines, I. Hatchery operations

High prices of prawn (Penaeus monodon) fry, profitability of hatchery operations, and a low cost hatchery design introduced by the Southeast Asian Fisheries Development Center attracted millions of dollars of investments in the mid-1980s. When export prices for prawn fell dramatically in 1989, demand for fry dropped as most prawn growers stopped operations or reduced stocking densities. Natural calamities – typhoons, earthquakes and volcanic eruptions – further depressed conditions in the hatchery sector. This paper presents an economic analysis of hatchery operations in the Philippines using data gathered through interviews and structured questionnaires in 1992. Economic indicators estimated include: investment requirements, unit cost, benefit over cost ratios, and internal rates of return. Breakeven and sensitivity analyses of operating hatcheries were employed to determine the degree of risk and changes in profitability levels associated with different scales of operation given changes in output price, input price and production level. Results indicate that net income per production run was positive for all scales of hatchery operation in spite of the current adverse market conditions. New hatchery investments, however, should be made in medium- and small-scale facilities because these have a better chance to survive worsening market conditions and periodic spawner shortages. Medium-size operations provide the best returns, and large-scale operations showed negative returns. Large-scale hatcheries are operating below capacity due to scarcity of spawners and low market demand

Aquaculture economics in Asia and the Pacific: A regional assessment

As aquaculture expands in importance globally, there is an increasing need for corresponding economic information, to aid managers, policy-makers and planners. This document seeks to provide a review of the current state of this aquaculture economics information and research base in developing countries, based on a comprehensive compilation of available literature on the subject. A broad integrated view is adopted, encompassing micro- and macro-economics, market analysis, socio-economics and environmental economics, the relationship with non-aquaculture economic activities (household economics), as well as relevant socio-cultural considerations. The circular contains two principal components. First, there is a set of regional assessments (Africa and the Middle East, Latin America and the Caribbean, Asia and the Pacific) reviewing the economics of aquaculture activity, the state of the art in aquaculture economics research, and research priorities for the future, on a region-by-region basis. Second, a set of annotated bibliographies is provided, one for each of the three regions, together with a bibliography of general references. In total, 1 154 references are included: 77 General; 223 for Africa and the Middle East; 133 for Latin America and the Caribbean; and 721 for Asia and the Pacific. Each bibliography documents available literature on the economics of aquaculture systems, emphasizing the most recent literature but also including older literature as relevant to the current state of aquaculture. All bibliographies are indexed according to country, aquatic species, production environment, production system and eight economic subject areas.A broad overview is given of research and information on aquaculture economics in Asia and the Pacific. Following a description of the general state of aquaculture in the region, an examination is made of the available research and information on the various aquaculture systems: inland/freshwater aquaculture; brackishwater /coastal aquaculture; and, marine aquaculture/sea farming. Studies on post-harvest handling, processing, transportation and marketing, and market analysis and development are discussed. Environmental issues and concerns, social equity and women's issues, community-based coastal resources management, technology transfer and macro-economic policies and institutional structures are also analysed. Aquaculture economics research is also assessed, highlighting thrusts, priorities, constraints and needs