119 research outputs found
Analysis of Long-range Clean Energy Investment Scenarios forEritrea, East Africa
We discuss energy efficiency and renewable energy investments in Eritrea from the strategic long-term economic perspective of meeting Eritrea's sustainable development goals and reducing greenhouse gas emissions. Energy efficiency and renewable energy are potentially important contributors to national productive capital accumulation, enhancement of the environment, expansion of energy services, increases in household standard of living, and improvements in health. In this study we develop a spreadsheet model for calculating some of the national benefits and costs of different levels of investment in energy efficiency and renewable energy. We then present the results of the model in terms of investment demand and investment scenario curves. These curves express the contribution that efficiency and renewable energy projects can make in terms of reduced energy sector operating expenses, and reduced carbon emissions. We provide demand and supply curves that show the rate of return, the cost of carbon emissions reductions vs. supply, and the evolution of the marginal carbon emissions per dollar of GDP for different investment levels and different fuel-type subsectors
Minimum energy performance standards for the 1.5 °C target: an effective complement to carbon pricing
Radical energy efficiency improvements are needed to keep global warming within 1.5 °C until the end of the century. Minimum energy performance standards (MEPS) are a widely applied policy instrument to improve the energy efficiency of appliances and reduce CO2 emissions, but they are criticized as redundant if an overarching carbon pricing scheme is in place. In order to better understand how MEPS could play a more effective role in reaching the 1.5 °C target, life cycle costs (LCC) for four home appliances were modelled considering a cost for emitting CO2. First, a significant social cost of carbon was introduced in a LCC optimisation model and it was found that a modest tightening of MEPS is sufficient to account for the climate externality. Second, more stringent MEPS were modelled and it was found that the switching prices needed to incentivize a shift up one or two efficiency classes were far higher than current carbon prices. These results have several implications for climate policy towards the 1.5 °C target. MEPS can easily internalize the climate externality and have the advantage over carbon pricing that policy makers can be certain that consumers actually move to more efficient appliances. While stringent MEPS do not appear to be economically efficient on the short-run, they are likely cost-effective in long-run 1.5 °C-consistent scenarios
Treatment of Rheumatoid Arthritis with Marine and Botanical Oils: Influence on Serum Lipids
The gap in mortality between patients with rheumatoid arthritis (RA) and the general population (1.5–3.0 fold risk) is increasing. This disparity is attributable mainly to cardiovascular disease (CVD), as the CVD risk is comparable to patients with diabetes mellitus. The purpose of this study is to determine whether borage seed oil rich in gamma-linolenic acid, fish oil rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), or the combination of both oils are useful treatments for dyslipidemia in patients with RA. We randomized patients into a double blind, 18 month trial. Mixed effects models were used to compare trends over time in serum lipids. No significant differences were observed between the three groups: All three treatment groups exhibited similar meaningful improvement in the lipid profile at 9 and 18 months. When all groups were combined, these treatments significantly reduced total and LDL-cholesterol and triglycerides, increased HDL-cholesterol, and improved the atherogenic index. All improvements observed at 9 months persisted at 18 months (P < 0.001 verses baseline). Conclusion. Marine and botanical oils may be useful treatment for rheumatoid arthritis patients who are at increased risk for cardiovascular disease compared to the general population
Treatment of Rheumatoid Arthritis with Marine and Botanical Oils: Influence on Serum Lipids (poster)
Background: Over the past 30 years substantial progress has been made in the medical and surgical management of patients with rheumatoid arthritis (RA). Despite this progress, there is an increasing gap in mortality between patients with RA (1.5-3.0 fold risk) and the general population. This disparity is mainly attributable to cardiovascular disease (CVD) as the CVD risk is comparable in RA patients as to patients with diabetes mellitus. Although the reasons for this gap are not entirely clear, the traditional risk of abnormalities in lipid profiles appears to be enhanced by a chronic increase in inflammatory cytokines, resulting in accelerated atherosclerosis.
Study Objective: The object of this study was to determine the effect of marine (fish oil) and botanical oils (borage oil) on lipids (TC, HDL, LDL, TG), a risk factor for cardiovascular disease in patients with RA. The main outcome (to be presented elsewhere) was to determine whether a combination of borage seed oil rich in gammalinolenic acid (GLA) and fish oil rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is superior to either oil alone for the treatment of RA.
Population and Setting: The study was an 18 month randomized, double-masked comparison of borage seed oil, fish oil, and the combination of both oils in RA patients with active synovitis.
Intervention: Patients received 3.5 gm omega-3 fatty acids daily in a 2.1gm EPA/1.4 gm DHA ratio (7 fish oil and 6 sunflower oil capsules daily); or 1.8 gm /d GLA (6 borage oil and 7 sunflower oil capsules /d); or 7 fish oil and 6 borage oil capsules daily (combination therapy).
Discussion: Rheumatoid Arthritis (RA) is a chronic systemic inflammatory disease. Mediators of inflammation and prothrombotic factors contribute to endothelial dysfunction and development of cardiovascular disease in RA patients. Marine and botanical oils represent an excellent primary or secondary therapy for improvement of the cardiovascular risk management in RA.
Patients taking these oils exhibit significant additional reductions in total and LDL-cholesterol, triglycerides, the TC/HDL ratio, and in the atherogenic index, and experience a significant increase in HDL-cholesterol. All of these improvements in the lipid profile were seen after 9 months of therapy, and increased after 18 months of oils administration.
The overall dropout rate was 51%, and was similar across groups: 25 in the borage oil group, 28 in the fish oil group, and 22 in the combination group. Reasons for dropout were mainly gastrointestinal distress (belching, bloating, diarrhea, nausea, cramping), or an inability to swallow the large number of rather sizable capsules. This can be ameliorated by freezing the capsules and reducing their size. Among those evaluated for this study, compliance was 100%, assessed by pill counts.
Learning Outcome: All treatments were safe, thus treatment of RA patients with one or a combination of these or similar oils should prove useful for reduction of cardiovascular risk in RA patients
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Conservation in California during the summer of 2001
The goal of this study is to measure the results of energy-conservation, energy-efficiency, and load-reduction measures in the California Independent System Operator (CAISO) region during the summer of 2001. During the period leading up to summer 2001, California experienced power outages and unprecedented instability in electricity and natural gas markets. Expecting that warm summer temperatures would exacerbate the already unstable energy market, state agencies and utilities created conservation and load-reduction programs that included advertisements and publicity, bill discounts for decreased customer electricity use, and financial payments for real-time load interruptions. Because the state avoided major electricity grid disturbances during the summer, few of the load-reduction programs were tested; however, the conservation and energy-efficiency programs appear to have been quite effective. The purpose of this study is to determine the extent to which electricity loads decreased in summer 2001 relative to summer 2000 and summer 1999, independent of differences in weather patterns. Our assumption is that the portion of load reduction that is not attributable to weather can be attributed to energy-efficiency and conservation measures. To determine the load reduction, we adjusted year 1999 and year 2000 hourly loads to simulate what load would have been under year 2001 weather conditions given the use patterns of years 1999 and 2000. The resulting load growth profile for 2001 was then compared with the load growth between 1999 and 2000 to determine how the pattern of load growth was affected by the energy crisis and the conservation programs put into place in response to it
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Refrigerator Efficiency in Ghana: Tailoring an appliance markettransformation program design for Africa
A simple replication of developed country applianceefficiency labels and standards is unlikely to be feasible in Ghana andmany other countries in Africa. Yet by creatively modifying the developedcountry appliance efficiency market transformation model, it should bepossible to achieve dramatic energy use reductions. As was true indeveloped countries in the previous two decades, refrigeration efficiencyimprovements provide the greatest energy savings potential in theresidential electricity sector in Ghana. Although Ghana, like manyAfrican countries may impose standards on imports since Ghana does nothave manufacturing facilities for appliances in country. This approachmay hurt some consumers who patronize a very diverse market of usedappliances imported from Europe. We discuss how meeting the challenges ofthe Ghanaian market will require modification of the usual energyefficiency labeling and standards paradigm. But once a refrigeratormarket transformation is accomplished in Ghana, we estimate an averageenergy savings potential of 550 kWh/refrigerator/year, and a monetarysavings of more than $35/refrigerator/year. We discuss how this modifiedrefrigerator efficiency market transformation may occur in the Ghanaiancontext. If successful, this market transformation is likely to be anexample for many other African countries
Predator‐induced changes in the chemical defence of a vertebrate
1. Inducible defences are ubiquitous in the animal kingdom, but little is known about
facultative changes in chemical defences in response to predators, especially so in
vertebrates.
2. We tested for predator‐induced changes in toxin production of larval common
toads (Bufo bufo), which are known to synthesize bufadienolide compounds.
3. The experiment included larvae originating from three permanent and three temporary
ponds reared in the presence or absence of chemical cues of three predators:
dragonfly larvae, newts or fish.
4. Tadpoles raised with chemical cues of predation risk produced higher numbers
of bufadienolide compounds and larger total bufadienolide quantities than predator‐
naive conspecifics. Further, the increase in intensity of chemical defence was
greatest in response to fish, weakest to newts and intermediate to dragonfly larvae.
Tadpoles originating from temporary and permanent ponds did not differ in their
baseline toxin content or in the magnitude of their induced chemical responses.
5. These results provide the first compelling evidence for predator‐induced changes
in chemical defence of a vertebrate that may have evolved to enhance survival under
predation risk
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Incorporating Experience Curves in Appliance Standards Analysis
The technical analyses in support of U.S. energy conservation standards for residential appliances and commercial equipment have typically assumed that manufacturing costs and retail prices remain constant during the projected 30-year analysis period. There is, however, considerable evidence that this assumption does not reflect real market prices. Costs and prices generally fall in relation to cumulative production, a phenomenon known as experience and modeled by a fairly robust empirical experience curve. Using price data from the Bureau of Labor Statistics, and shipment data obtained as part of the standards analysis process, we present U.S. experience curves for room air conditioners, clothes dryers, central air conditioners, furnaces, and refrigerators and freezers. These allow us to develop more representative appliance price projections than the assumption-based approach of constant prices. These experience curves were incorporated into recent energy conservation standards for these products. The impact on the national modeling can be significant, often increasing the net present value of potential standard levels in the analysis. In some cases a previously cost-negative potential standard level demonstrates a benefit when incorporating experience. These results imply that past energy conservation standards analyses may have undervalued the economic benefits of potential standard levels
Zonal surface wind jets across the Red Sea due to mountain gap forcing along both sides of the Red Sea
Author Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 36 (2009): L19605, doi:10.1029/2009GL040008.Mesoscale atmospheric modeling over the Red Sea, validated by in-situ meteorological buoy data, identifies two types of coastal mountain gap wind jets that frequently blow across the longitudinal axis of the Red Sea: (1) an eastward-blowing summer daily wind jet originating from the Tokar Gap on the Sudanese Red Sea coast, and (2) wintertime westward-blowing wind-jet bands along the northwestern Saudi Arabian coast, which occur every 10–20 days and can last for several days when occurring. Both wind jets can attain wind speeds over 15 m s−1 and contribute significantly to monthly mean surface wind stress, especially in the cross-axis components, which could be of importance to ocean eddy formation in the Red Sea. The wintertime wind jets can cause significant evaporation and ocean heat loss along the northeastern Red Sea coast and may potentially drive deep convection in that region. An initial characterization of these wind jets is presented.Supported by Award Numbers USA
00001, USA 00002, and KSA 00011 made by KAUST
Vms1 and ANKZF1 peptidyl-tRNA hydrolases release nascent chains from stalled ribosomes
Ribosomal surveillance pathways scan for ribosomes that are transiently paused or terminally stalled owing to structural elements in mRNAs or nascent chain sequences. Some stalls in budding yeast are sensed by the GTPase Hbs1, which loads Dom34, a catalytically inactive member of the archaeo-eukaryotic release factor 1 superfamily. Hbs1–Dom34 and the ATPase Rli1 dissociate stalled ribosomes into 40S and 60S subunits. However, the 60S subunits retain the peptidyl-tRNA nascent chains, which recruit the ribosome quality control complex that consists of Rqc1–Rqc2–Ltn1–Cdc48–Ufd1–Npl4. Nascent chains ubiquitylated by the E3 ubiquitin ligase Ltn1 are extracted from the 60S subunit by the ATPase Cdc48–Ufd1–Npl4 and presented to the 26S proteasome for degradation. Failure to degrade the nascent chains leads to protein aggregation and proteotoxic stress in yeast and neurodegeneration in mice. Despite intensive investigations on the ribosome quality control pathway, it is not known how the tRNA is hydrolysed from the ubiquitylated nascent chain before its degradation. Here we show that the Cdc48 adaptor Vms1 is a peptidyl-tRNA hydrolase. Similar to classical eukaryotic release factor 1, Vms1 activity is dependent on a conserved catalytic glutamine. Evolutionary analysis indicates that yeast Vms1 is the founding member of a clade of eukaryotic release factor 1 homologues that we designate the Vms1-like release factor 1 clade
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