3,614 research outputs found
Economic and Groundwater Use Implications of Climate Change and Bioenergy Feedstock Production in the Ogallala Aquifer Region
The sustainable water use especially for irrigated agriculture in the Texas Panhandle Region is a major concern. A semi-arid climate and average low rainfalls results in little surface water being available year-round. The Ogallala Aquifer is the primary source of irrigation water in this region. The intensive irrigated agricultural production and growing livestock industry have led to substantial decline of water tables. Furthermore, climate change and growing bioenergy feedstock productions exacerbates the water shortage and quality problems. Given the critical dependence of the regional economy on Ogallala Aquifer, underground water use is an intergenerational issue that must be evaluated in terms of the sustainability of agricultural activities in the long run. This paper develops a dynamic multi-county land allocation optimization model which integrates three sectors: agriculture, climate and hydrology. The sustainable water use and associated irrigated agricultural economic consequences under climate change are analyzed. This model also serves as a policy tool in evaluating economic impacts of alternative bioenergy expansion policies and water saving technologies in Ogallala Aquifer Region. The simulation results show that availability of extractable water has a direct impact on optimal land allocation. Deficit irrigation for major crops is an effective short-run strategy for water sustainability. In the longer run, dryland and pastureland farming will dominate. Climate change has heterogeneous impacts on agricultural production over counties and sub-counties because of the non-uniform hydrological characteristics.Groundwater, Land Use Change, Climate Change, Bioenergy feedstock, Dynamic Optimization Model, Deficit Irrigation, Environmental Economics and Policy, Land Economics/Use, Resource /Energy Economics and Policy, Q24, Q25, Q54,
Dryland Wheat variety selection in the Texas High Plain
Selecting the best wheat varieties affects producers’ profit and financial risk. This study identifies the optimal wheat variety selection using the portfolio approach at various risk aversion levels. Results showed that the optimal wheat variety selection was significantly affected by changes in levels of risk aversion of decision makersDryland, Portfolio, risk, wheat Variety, Farm Management,
Tonicity response element binding protein associated with neuronal cell death in the experimental diabetic retinopathy
AIM: To study the contribution of tonicity response element binding protein (TonEBP) in retinal ganglion cell (RGC) death of diabetic retinopathy (DR).
METHODS: Diabetes was induced in C57BL/6 mice by five consecutive intraperitoneal injections of 55 mg/kg streptozotocin (STZ). Control mice received vehicle (phosphate -buffered saline). All mice were killed 2mo after injections, and the extent of cell death and the protein expression levels of TonEBP and aldose reductase (AR) were examined.
RESULTS: The TonEBP and AR protein levels and the death of RGC were significantly increased in the retinas of diabetic mice compared with controls 2mo after the induction of diabetes. Terminal deoxynucleotidyl transferase (TdT) -mediated dUTP nick end labeling (TUNEL) -positive signals co -localized with TonEBP immunoreactive RGC. These changes were increased in the diabetic retinas compared with controls.
CONCLUSION: The present data show that AR and TonEBP are upregulated in the DR and TonEBP may contribute to apoptosis of RGC in the DR.close2
The effect of Fe atoms on the adsorption of a W atom on W(100) surface
We report a first-principles calculation that models the effect of iron (Fe)
atoms on the adsorption of a tungsten (W) atom on W(100) surfaces. The
adsorption of a W atom on a clean W(100) surface is compared with that of a W
atom on a W(100) surface covered with a monolayer of Fe atoms. The total energy
of the system is computed as the function of the height of the W adatom. Our
result shows that the W atom first adsorbs on top of the Fe monolayer. Then the
W atom can replace one of the Fe atoms through a path with a moderate energy
barrier and reduce its energy further. This intermediate site makes the
adsorption (and desorption) of W atoms a two-step process in the presence of Fe
atoms and lowers the overall adsorption energy by nearly 2.4 eV. The Fe atoms
also provide a surface for W atoms to adsorb facilitating the diffusion of W
atoms. The combination of these two effects result in a much more efficient
desorption and diffusion of W atoms in the presence of Fe atoms. Our result
provides a fundamental mechanism that can explain the activated sintering of
tungsten by Fe atoms.Comment: 9 pages, 2 figure
Highly stacked 3D organic integrated circuits with via-hole-less multilevel metal interconnects
Multilevel metal interconnects are crucial for the development of large-scale organic integrated circuits. In particular, three-dimensional integrated circuits require a large number of vertical interconnects between layers. Here, we present a novel multilevel metal interconnect scheme that involves solvent-free patterning of insulator layers to form an interconnecting area that ensures a reliable electrical connection between two metals in different layers. Using a highly reliable interconnect method, the highest stacked organic transistors to date, a three-dimensional organic integrated circuits consisting of 5 transistors and 20 metal layers, is successfully fabricated in a solvent-free manner. All transistors exhibit outstanding device characteristics, including a high on/off current ratio of similar to 10(7), no hysteresis behavior, and excellent device-to-device uniformity. We also demonstrate two vertically-stacked complementary inverter circuits that use transistors on 4 different floors. All circuits show superb inverter characteristics with a 100% output voltage swing and gain up to 35 V per V.11Ysciescopu
488 MENISCAL REPLACEMENT IN CANINE MODEL USING AUTOLOGOUS SYNOVIUM-DERIVED STEM CELLS-SEEDED SCAFFOLD
The in vitro effects of dehydroepiandrosterone on human osteoarthritic chondrocytes
AbstractObjective: To investigate the in vitro effects of dehydroepiandrosterone (DHEA) on human osteoarthritic chondrocytes.Design: Chondrocytes isolated from human osteoarthritic knee cartilage were three-dimensionally cultured in alginate beads, except for cell proliferation experiment. Cells were treated with DHEA in the presence or absence of IL-1β. The effects on chondrocytes were analyzed using a 3-(4,5-dimethylthiazol-2yl)-5-(3-carboxymethoxy-phenyl)-2-(4-sulfophenyl)-2H-tetrazolium inner salt (MTS) assay (for chondrocyte proliferation), a dimethylmethylene blue (DMB) assay (for glycosaminoglycan (GAG) synthesis), and an indole assay (for DNA amount). Gene expressions of type I and II collagen, metalloproteinase-1 and -3 (MMP-1 and -3), and tissue inhibitor of metalloproteinase-1 (TIMP-1) as well as the IL-1β-induced gene expressions of MMP-1 and -3 were analyzed by reverse transcription-polymerase chain reaction (RT-PCR). The protein synthesis of MMP-1 and -3 and TIMP-1 was determined by Western blotting.Results: The treatment of chondrocytes with DHEA did not affect chondrocyte proliferation or GAG synthesis up to 100μM of concentration. The gene expression of type II collagen increased in a dose-dependent manner, while that of type I decreased. DHEA suppressed the expression of MMP-1 significantly at concentrations exceeding 50μM. The gene expression of MMP-3 was also suppressed, but this was without statistical significance. The expression of TIMP-1 was significantly increased by DHEA at concentrations exceeding 10μM. The effects of DHEA on the gene expressions of MMP-1 and -3 were more prominent in the presence of IL-1β, in which DHEA suppressed not only MMP-1, but also MMP-3 at the lower concentrations, 10 and 50μM, respectively. Western blotting results were in agreement with RT-PCR, which indicates that DHEA acts at the gene transcription level.Conclusions: Our study demonstrates that DHEA has no toxic effect on chondrocytes up to 100μM of concentration and has an ability to modulate the imbalance between MMPs and TIMP-1 during OA at the transcription level, which suggest that it has a protective role against articular cartilage loss
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