464 research outputs found
Irrigation efficiency and water-policy implications for river basin resilience
Rising demand for food, fiber, and biofuels drives
expanding irrigation withdrawals from surface water and groundwater. Irrigation
efficiency and water savings have become watchwords in response to
climate-induced hydrological variability, increasing freshwater demand for
other uses including ecosystem water needs, and low economic productivity of
irrigation compared to most other uses. We identify three classes of
unintended consequences, presented here as paradoxes. Ever-tighter cycling
of water has been shown to increase resource use, an example of the
<i>efficiency paradox</i>. In the absence of effective policy to
constrain irrigated-area expansion using "saved water", efficiency can
aggravate scarcity, deteriorate resource quality, and impair river basin
resilience through loss of flexibility and redundancy. Water scarcity and
salinity effects in the lower reaches of basins (symptomatic of the
<i>scale paradox</i>) may partly be offset over the short-term through
groundwater pumping or increasing surface water storage capacity. However,
declining ecological flows and increasing salinity have important
implications for riparian and estuarine ecosystems and for non-irrigation
human uses of water including urban supply and energy generation, examples
of the <i>sectoral paradox</i>. This paper briefly considers three
regional contexts with broadly similar climatic and water-resource
conditions – central Chile, southwestern US, and south-central
Spain – where irrigation efficiency directly influences basin resilience.
The comparison leads to more generic insights on water policy in relation to
irrigation efficiency and emerging or overdue needs for environmental protection
Analyzing climate change adaptation in the agriculture and water sectors: screening risks and opportunities.
As part of the Mediterranean area, the Guadiana basin in
Spain is particularly exposed to increasing water stress
due to climate change. Future warmer and drier climate
will have negative implications for the sustainability of
water resources and irrigation agriculture, the main socio-
economic sector in the region. This paper illustrates a
systematic analysis of climate change impacts and adaptation in the Guadiana basin based on a two-stage modeling approach. First, an integrated hydro-economic modeling framework was used to simulate the potential
effects of regional climate change scenarios for the period 2000-2069. Second, a participatory multi-criteria technique, namely the Analytic Hierarchy Process (AHP), was applied to rank potential adaptation measures based on agreed criteria. Results show that, in the middle-long run and under severe climate change, reduced water availability, lower crop yields and increased irrigation demands might lead to water shortages, crop failure, and up to ten percent of income losses to irrigators. AHP results show how private farming adaptation measures, including improving irrigation efficiency and adjusting crop
varieties, are preferred to public adaptation measures,
such as building new dams. The integrated quantitative and qualitative methodology used in this research can be
considered a socially-based valuable tool to support adaptation decision-making
In vivo activity of plant-based interleukin-12 in the lung of Balb/c mouse
<p>Abstract</p> <p>Background</p> <p>In the last years, plants are being used for the production of a wide variety of biopharmaceuticals, including cytokines, and have the potential to serve as vehicles for mucosal administration of these molecules. We had previously reported the expression of a cytokine, interleukin-12 (IL-12), in transgenic tomato plants and had demonstrated that it retained its biologic activity <it>in vitro</it>.</p> <p>Findings</p> <p>In this work, we administered crude extracts of IL-12-containing tomato fruits to mice through the intratracheal route, measuring endogenous IL-12 and determining biologic activity by quantification of interferon-gamma (IFN-γ) in lungs and by histological analysis. IFN-γ expression in lungs, as well as histological analysis, indicate that tomato-expressed IL-12 retains its biologic activity and, most importantly, its effects are restricted to the site of administration.</p> <p>Conclusion</p> <p>Our results indicate that the functional activity of tomato-expressed IL-12 is comparable to that of commercial recombinant IL-12 when given via the mucosal route. This opens the possibility of using crude extracts prepared from tomatoes expressing IL-12 for certain immunotherapies.</p
Protective Effect of Melatonin Against Mitomycin C-Induced Genotoxic Damage in Peripheral Blood of Rats
Mitomycin C (MMC) generates free radicals when metabolized. We investigated the effect of melatonin against MMC-induced genotoxicity in polychromatic erythrocytes and MMC-induced lipid peroxidation in brain and liver homogenates. Rats (N = 36) were classified into 4 groups: control, melatonin, MMC, and MMC + melatonin. Melatonin and MMC doses of
10 mg/kg and 2 mg/kg, respectively, were injected intraperitoneally. Peripheral blood samples were collected at 0, 24, 48, 72, and 96 hours posttreatment and homogenates were obtained at 96 hours posttreatment. The number of micronucleated polychromatic erythrocytes (MN-PCE) per 1000 PCE was used as a genotoxic marker. Malondialdehyde (MDA) plus 4-hydroxyalkenal (4-HDA) levels were used as an index of lipid peroxidation. The MMC group showed a significant increase in MN-PCE at 24, 48, 72, and 96 hours that was significantly reduced with melatonin begin coadministrated. No significant differences were found in lipid peroxidation. Our results indicate that MMC-induced genotoxicity can be reduced by melatonin
Dinámicas socioecológicas y ecoturismo comunitario: Un análisis comparativo en el eje fluvial Guayabero-Guaviare
The effects of the ecotourism in the relationships between inhabitants and their environment are complex and multidimensional. To explore these effects, two community ecotourism initiatives in the Guaviare Province were comparatively analyzed. This territory has been historically affected by the armed conflict and today is given priority as a scenery for the peace construction. The analysis herein articulates approaches both from the political ecology and the socio-ecological systems and considers how important it is to understand the power relations emerging in community ecotourism contexts that, in turn, help to measure how this kind of tourism impacts the socio-ecological dynamics and the strategies by the peasant families who try to diversify their economies to made them sustainable. © 2018, Pontificia Universidad Javeriana. All rights reserved
Whole system approaches for managing land-use change to deliver multiple benefits from biodiversity in tropical forest landcapes
Presentamos en una sesión dedicada al proyecto ROBIN: Session No. 101: Whole system approaches for managing land-use change to deliver multiple benefits from biodiversity in tropical forest landcapes (Chairs: Terry Parr, Michael Schmidt, Kirsten Thonicke - Theme 3
How can irrigated agriculture adapt to climate change? Insights from the Guadiana Basin in Spain
Climate change is already affecting many natural systems and human environments worldwide, like the semiarid Guadiana Basin in Spain. This paper illustrates a systematic analysis of climate change adaptation in the Guadiana irrigation farming region. The study applies a solution-oriented diagnostic framework structured along a series of sequential analytical steps. An initial stage integrates economic and hydrologic modeling to evaluate the effects of climate change on the agriculture and water sectors. Next, adaptation measures are identified and prioritized through a stakeholder-based multi-criteria analysis. Finally, a social network analysis identifies key actors and their relationships in climate change adaptation. The study shows that under a severe climate change scenario, water availability could be substantially decreased and drought occurrence will augment. In consequence, farmers will adapt their crops to a lesser amount of water and income gains will diminish, particularly for smallholder farms. Among the various adaptation measures considered, those related to private farming (new crop varieties and modern irrigation technologies) are ranked highest, whereas public-funded hard measures (reservoirs) are lowest and public soft measures (insurance) are ranked middle. In addition, stakeholders highlighted that the most relevant criteria for selecting adaptation plans are environmental protection, financial feasibility and employment creation. Nonetheless, the social network analysis evidenced the need to strengthen the links among the different stakeholder groups to facilitate the implementation of adaptation processes. In sum, the diagnostic framework applied in this research can be considered a valuable tool for guiding and supporting decision making in climate change adaptation and communicating scientific results
Oxygen and nitrogen abundances of HII regions in six spiral galaxies
Spectroscopic observations of 63 HII regions in six spiral galaxies (NGC 628,
NGC 783, NGC 2336, NGC 6217, NGC 7331, and NGC 7678) were carried out with the
6-meter telescope (BTA) of Russian Special Astrophysical Observatory with the
Spectral Camera attached to the focal reducer SCORPIO in the multislit mode
with a dispersion of 2.1A/pixel and a spectral resolution of 10A. These
observations were used to estimate the oxygen and nitrogen abundances and the
electron temperatures in HII regions through the recent variant of the strong
line method (NS calibration). The parameters of the radial distribution (the
extrapolated central intercept value and the gradient) of the oxygen and
nitrogen abundances in the disks of spiral galaxies NGC 628, NGC 783, NGC 2336,
NGC 7331, and NGC 7678 have been determined. The abundances in the NGC 783, NGC
2336, NGC 6217, and NGC 7678 are measured for the first time. Galaxies from our
sample follow well the general trend in the luminosity - central metallicity
diagram for spiral and irregular galaxies.Comment: 11 pages, 7 figures, 6 tables. Accepted for publication in MNRA
Long-term efficacy of orthokeratology contact lens wear in controlling the progression of childhood myopia
Purpose: The primary outcome of this study is to compare the axial length growth of white European myopic children wearing orthokeratology contact lenses (OK) to a control group (CT) over a 7-year period. Methods: Subjects 6–12 years of age with myopia −0.75 to −4.00DS and astigmatism ≤1.00DC were prospectively allocated OK or distance single-vision spectacles (SV) correction. Measurements of axial length (Zeiss IOLMaster), corneal topography, and cycloplegic refraction were taken at 6-month intervals over a 2-year period. Subjects were invited to return to the clinic approximately 5 years later (i.e., 7 years after the beginning of the study) for assessment of their ocular refractive and biometric components. The CT consisted of 4 SV and 12 subjects who switched from SV to soft contact lens wear after the initial 2 years of SV lens wear. Changes in axial length relative to baseline over a 7-year period were compared between groups. Results: Fourteen and 16 subjects from the OK and CT groups, respectively, were examined 6.7 ± 0.5 years after the beginning of the study. Statistically significant changes in the axial length were found over time and between groups (both p <0.001), but not for the time*group interaction (p = 0.125). The change in the axial length for the OK group was 22% (p = 0.328), 42% (p = 0.007), 40% (p = 0.020), 41% (p = 0.013), and 33% (p = 0.062) lower than the CT group following 6, 12, 18, 24, and 84 months of lens wear, respectively. Conclusion: A trend toward a reduction in the rate of axial elongation of the order of 33% was found in the OK group in comparison to the CT group following 7 years of lens wear
Analyzing adaptation to climate change in the water and the agricultural sectors in the Spanish Guadiana basin.
1. Introduction: setting and problem definition
2. The Adaptation Pathway
–2.1 Stage 1: appraising risks and opportunities
•Step 1: Impact analysis
•Step 2: Policy analysis
•Step 3: Socio-institutional analysis
–2.2 Stage 2: appraising and choosing adaptation opt
ions
•Step 4: identifying and prioritizing adaptation o
ptions
3. Conclusion
- …