7,325 research outputs found
Sensitivity of a climatologically-driven sea ice model to the ocean heat flux
Ocean heat flux sensitivity was studied on a numerical model of sea ice covering the Weddell Sea region of the southern ocean. The model is driven by mean monthly climatological atmospheric variables. For each model run, the ocean heat flux is uniform in both space and time. Ocean heat fluxes below 20 W m to the minus 2 power do not provide sufficient energy to allow the ice to melt to its summertime thicknesses and concentrations by the end of the 14 month simulation, whereas ocean heat fluxes of 30 W m to the minus 2 power and above result in too much ice melt, producing the almost total disappearance of ice in the Weddell Sea by the end of the 14 months. These results are dependent on the atmospheric forcing fields
Low dimensional magnetic solids and single crystal elpasolites: Need for improved crystal growing techniques
The need for extensive crystal growing experiments to develop techniques for preparing crystals suitable for magnetic anisotropy measurements and detailed X-ray and neutron diffraction studies is rationalized on the basis of the unique magnetic properties of the materials and their hydrogen bonded structures which have many features in common with metalloenzyme and metalloprotein active sites. Single crystals of the single and mixed lanthanide species are prepared by the Bridgeman technique of gradient solidification of molten samples. The effects of crystal imperfections on the optical properties of these materials are an important part of the projected research. A series of a-amido acid complexes of first row transition metals were prepared which crystallize as infinite linear chains and exhibit low dimensional magnetic ordering (one or two) at temperature below 40 K
Polyhexamethylene Biguanide and Nadifloxacin Self-Assembled Nanoparticles: Antimicrobial Effects against Intracellular Methicillin-Resistant Staphylococcus aureus
The treatment of skin and soft tissue infections caused by methicillin-resistant Staphylococcus aureus (MRSA) remains a challenge, partly due to localization of the bacteria inside the host’s cells, where antimicrobial penetration and efficacy is limited. We formulated the cationic polymer polyhexamethylene biguanide (PHMB) with the topical antibiotic nadifloxacin and tested the activities against intracellular MRSA in infected keratinocytes. The PHMB/nadifloxacin nanoparticles displayed a size of 291.3 ± 89.6 nm, polydispersity index of 0.35 ± 0.04, zeta potential of +20.2 ± 4.8 mV, and drug encapsulation efficiency of 58.25 ± 3.4%. The nanoparticles killed intracellular MRSA, and relative to free polymer or drugs used separately or together, the nanoparticles displayed reduced toxicity and improved host cell recovery. Together, these findings show that PHMB/nadifloxacin nanoparticles are effective against intracellular bacteria and could be further developed for the treatment of skin and soft tissue infections
Style and Performance of Agricultural Market Advisory Services
This paper describes the degree of marketing activeness of market advisory programs for corn and soybeans, and analyzes the relationship between activeness degree and pricing performance. The data set employed consists of advisory programs tracked by the AgMAS Project at the University of Illinois between 1995 and 2001. Cluster analysis was conducted to group the programs according to their degree of activeness. Panel data regression models were estimated to evaluate the relationship between activeness degree and pricing performance. In the corn market, point estimates indicate a positive effect of the degree of activeness on pricing performance, but this effect is of small magnitude and statistically insignificant. For soybeans,there is a stronger positive relationship between activeness degree and performance, with an estimated effect of activeness on performance larger in magnitude and statistically significant. This positive relationship suggests that active marketing programs are based on superior information and/or analytical skills.Agribusiness, Marketing,
AN EVALUATION OF CROP FORECAST ACCURACY FOR CORN AND SOYBEANS: USDA AND PRIVATE INFORMATION SERVICES
Using 1971-2000 data, we examine the accuracy of corn and soybean production forecasts provided by the USDA and two private services. All agencies improved their forecasts as the harvest progressed, and forecast errors across the agencies were highly correlated. Relative accuracy varied by crop and month. In corn, USDA 's forecasts ranked as most accurate in all periods except in August during recent times, and improved more markedly as harvest progressed. In soybeans, forecast errors were very similar with the private agencies ranking as most accurate in August and September and making largest relative improvements in August during recent times. The USDA provided the most accurate October and November forecasts.Crop Production/Industries,
The Pricing Performance of Market Advisory Services in Corn and Soybeans Over 1995-2004
The purpose of this research report is to evaluate the pricing performance of market advisory services for the 1995-2004 corn and soybean crops. Marketing assumptions applied to advisory program track records are intended to accurately depict “real-world” marketing conditions facing a representative central Illinois corn and soybean farmer. Several key assumptions are: i) with a few exceptions, the marketing window for a crop year runs from September before harvest through August after harvest, ii) on-farm or commercial physical storage costs, as well as interest opportunity costs, are charged to post-harvest sales, iii) brokerage costs are subtracted for all futures and options transactions and iv) Commodity Credit Corporation (CCC) marketing loan recommendations made by advisory programs are followed wherever feasible. Based on these and other assumptions, the net price received by a subscriber to market advisory programs is calculated for the 1995-2004 corn and soybean crops. Market and farmer benchmarks are developed for the performance evaluations. Two market benchmarks are specified in order to test the sensitivity of performance results to changing benchmark assumptions. The 24-month market benchmark averages market prices for the entire 24-month marketing window. The 20-month market benchmark is computed in a similar fashion, except the first four months of the marketing window are omitted. Given the uncertainties involved in measuring the average price received by farmers, two alternative farmer benchmarks for central Illinois are specified. The market and farmer benchmarks are computed using the same assumptions applied to advisory program track records. Five basic indicators of performance are applied to advisory program prices and revenues over 1995-2004. Results show that advisory program prices fall in the top-third of the price range relatively infrequently. There is limited evidence that advisory programs as a group outperform market benchmarks, particularly after considering risk. The evidence is somewhat more positive with respect to farmer benchmarks, even after taking risk into account. For example, the average advisory return relative to the farmer benchmarks is 8 to $12 per acre with only a marginal increase in risk. Even though this return is small and mainly from corn, it nonetheless represents a non-trivial increase in net farm income per acre for grain farms in central Illinois. Test results also suggest that it is difficult to predict the year-to-year pricing performance of advisory programs based on past pricing performance. However, there is some evidence that performance is more predictable over longer time horizons, particularly at the extremes of performance rankings. The results raise the interesting possibility that even though advisory services do not appear to “beat the market,” they nonetheless provide the opportunity for some farmers to improve performance relative to the market. Mirroring debates about stock investing, the relevant issue is whether farmers can most effectively improve marketing performance by pursuing “active” strategies, like those recommended by advisory services, or “passive” strategies, which involve routinely spreading sales across the marketing window.Agricultural Finance, Financial Economics,
Isospin asymmetry and type-I superconductivity in neutron star matter
It has been argued by Buckley et. al.(Phys. Rev. Lett. 92, 151102, 2004) that
nuclear matter is a type-I rather than a type-II superconductor. The suggested
mechanism is a strong interaction between neutron and proton Cooper pairs,
which arises from an assumed U(2) symmetry of the effective potential, which is
supposed to originate in isospin symmetry of the underlying nuclear
interactions. To test this claim, we perform an explicit mean-field calculation
of the effective potential of the Cooper pairs in a model with a simple
four-point pairing interaction. In the neutron star context, matter is very
neutron rich with less than 10% protons, so there is no neutron-proton pairing.
We find that under these conditions our model shows no interaction between
proton Cooper pairs and neutron Cooper pairs at the mean-field level. We
estimate the leading contribution beyond mean field and find that it is is
small and attractive at weak coupling.Comment: 7 pages, 2 figure
The Marketing Performance of Illinois and Kansas Wheat Farmers
The purpose of this paper is to analyze the marketing performance of wheat farmers in Illinois and Kansas over 1982–2004. The results show that farmer benchmark prices for wheat in Illinois and Kansas fall in the middle third of the price range about half to three-quarters of the time. Consistent with previous studies, this refutes the contention that Illinois and Kansas wheat farmers routinely market the bulk of their wheat crop in the bottom portion of the price range. Tests of the average difference between farmer and market benchmark prices are sensitive to the market benchmark considered. The marketing performance of wheat farmers in Illinois and Kansas is about equal to the market if a 24- or 20-month market benchmark is used, slightly above the market if a 12-month price benchmark is used, and significantly less than the market if the harvest benchmark is used. The sensitivity of marketing performance to the market benchmark considered is explained by the seasonal pattern of prices. While Illinois producers performed slightly better than their counterparts in Kansas, notable differences in performance across these two geographic areas is not observed.benchmarks, Illinois, Kansas, marketing, performance, price, wheat, Agribusiness, Crop Production/Industries, Marketing, Production Economics, Productivity Analysis, Q11, Q13,
The Cure: Making a game of gene selection for breast cancer survival prediction
Motivation: Molecular signatures for predicting breast cancer prognosis could
greatly improve care through personalization of treatment. Computational
analyses of genome-wide expression datasets have identified such signatures,
but these signatures leave much to be desired in terms of accuracy,
reproducibility and biological interpretability. Methods that take advantage of
structured prior knowledge (e.g. protein interaction networks) show promise in
helping to define better signatures but most knowledge remains unstructured.
Crowdsourcing via scientific discovery games is an emerging methodology that
has the potential to tap into human intelligence at scales and in modes
previously unheard of. Here, we developed and evaluated a game called The Cure
on the task of gene selection for breast cancer survival prediction. Our
central hypothesis was that knowledge linking expression patterns of specific
genes to breast cancer outcomes could be captured from game players. We
envisioned capturing knowledge both from the players prior experience and from
their ability to interpret text related to candidate genes presented to them in
the context of the game.
Results: Between its launch in Sept. 2012 and Sept. 2013, The Cure attracted
more than 1,000 registered players who collectively played nearly 10,000 games.
Gene sets assembled through aggregation of the collected data clearly
demonstrated the accumulation of relevant expert knowledge. In terms of
predictive accuracy, these gene sets provided comparable performance to gene
sets generated using other methods including those used in commercial tests.
The Cure is available at http://genegames.org/cure
Interpretation, translation and intercultural communication in refugee status determination procedures in the UK and France
This article explores the interplay between language and intercultural communication within refugee status determination procedures in the UK and France, using material taken from ethnographic research that involved a combination of participant observation, semi-structured interviews and documentary analysis in both countries over a two-year period (2007–2009). It is concerned, in particular, to examine the role played by interpreters in facilitating intercultural communication between asylum applicants and the different administrative and legal actors responsible for assessing or defending their claims. The first section provides an overview of refugee status determination procedures in the UK and France, introducing the main administrative and legal contexts of the asylum process within which interpreters operate in the two countries. The second section compares the organisation of interpreting services, codes of conduct for interpreters and institutional expectations about the nature of interpreters’ activity on the part of the relevant UK and French authorities. The third section then explores some of the practical dilemmas for interpreters and barriers to communication that exist in refugee status determination procedures in the two countries. The article concludes by emphasising the complex and active nature of the interpreter's role in UK and French refugee status determination procedures
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