4,267 research outputs found
Testing and validating the CERES-wheat (Crop Estimation through Resource and Environment Synthesis-wheat) model in diverse environments
CERES-Wheat is a computer simulation model of the growth, development, and yield of spring and winter wheat. It was designed to be used in any location throughout the world where wheat can be grown. The model is written in Fortran 77, operates on a daily time stop, and runs on a range of computer systems from microcomputers to mainframes. Two versions of the model were developed: one, CERES-Wheat, assumes nitrogen to be nonlimiting; in the other, CERES-Wheat-N, the effects of nitrogen deficiency are simulated. The report provides the comparisons of simulations and measurements of about 350 wheat data sets collected from throughout the world
The paradox of medical necessity
The concept of medical necessity is often used to explain or justify certain decisions—for example, which treatments should be allowed under certain conditions—as though it had an obvious, agreed-upon meaning as well as an inherent normative force. In introducing this special issue of Clinical Ethics on medical necessity, we argue that the term, as used in various discourses, generally lacks a definition that is clear, non-circular, conceptually plausible, and fit for purpose. We propose that future work on this concept should address three main questions: what medical necessity is (i.e., what makes something medically necessary, as opposed to something else); what the concept does (what ‘work’ is it doing when invoked in different settings); and what should follow, normatively, from the fact that something is indeed medically necessary (on some plausible conception)
Determinants of Tanzania and Kenya Trade in the East African Community: A Gravity Model Approach
The paper aims at studying the determinants of trade in the East African Community (EAC). The paper explains as to why despite having five members, the two countries Kenya and Tanzania dominates trade among EAC members.Using the aggregated gravity model, the study finds that, Tanzania and Kenya Trade are much determined by the economic size (GDP) of the EAC members rather than the Per capita GDPs of these countries. The coefficient of a distance variable has negative impact meaning the costs of trading, time related costs and costs related to market access are higher. In a disintegrated model, the economic size of the respective countries, Kenya and Tanzania,exerts a positive impact but Tanzania’s GDP have a higher value of coefficient than Kenya. The Tanzania’s importers GDPs coefficient is positive but not significant for Tanzania, while it is positive and significant for Kenya’s export Trade. Importers population showed a remarkable contribution to bilateral trade between Tanzania, Kenya and the rest of EAC. However, per capita income coefficient explains that Kenya and Tanzania does not trade high income oriented products for the coefficient had a negative sign which is significant. The distance, representing the cost of trading, is affects Tanzania export negatively more than how it does for Kenya. The exchange rate coefficient shows that price competition is important because for Tanzania lowering her currency does not half the export as if Kenya would do. Openness variable shows trade liberalization, perhaps the formation of EAC bloc;measures have significantly improved trade flows between EAC countries. Keywords: Gravity model, export oriented economy; Regional or Free Trade Agreements; production’s specialization and competitivenes
Sequence of the OXA2 β-lactamase: comparison with other penicillin-reactive enzymes
AbstractThe nucleotide sequence of the unusual plasmid-mediated OXA2 β-lactamase is presented, and compared with other β-lactamases. The OXA2 enzyme has similar features at the presumed active site, but no other significant regions ofhomology with other penicillin-reactive enzymes. The active site homology may therefore represent convergent evolution of otherwise dissimilar genes
More echoes from David Lodge’s Small World
David Lodge's Small World avoids closure, and further contains a seemingly endless number of references to prior texts. It thus encourages the reader to make his own interpretation of the book, based on his personal literary experiences. This study explores one possible interpretation, and draws an analog between Lodge's book and the great Baroque novels of seventeenth-century France
DISTRIBUTION OF IRON (II) BETWEEN BUFFERED AQUEOUS SOLUTIONS AND CHLOROFORM SOLUTION OF N,N’-ETHYLENEBIS(4-BUTANOYL-2,4-DIHYDRO-5-METHYL-2-PHENYL-3H-PYRAZOL-3-ONEIMINE)
The distribution of Fe(II) between buffered aqueous solution and chloroform solution of N,N’-Ethylenebis(4-butanoyl-2-4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-oneimine)(H2BuEtP) was investigated. The effect of 4-butanoyl-2-4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one(HBuP) in the distribution was also studied. Fe(II) concentration in aqueous raffinate was determined colorimetrically and distribution ratios and percentage extractions calculated by difference from Fe(II) in aqueous phase before and after equilibrations. The optimal pH for Fe(II) distribution slightly lowered to 8.00 in mixed ligands(H2BuEtP/HBuP) organic phase from 8.25 in ligand (H2BuEtP) alone organic phase. The pH range at which quantitative extraction of Fe(II) from aqueous buffered solution into both type of organic phases used for the study was very narrow. The extraction parameters; pH1/2, log D from extraction plots, and log Kex calculated using extraction equations derived from slope analysis showed that the values in both type of organic phases were very close even though mixed ligands(H2BuEtP/HBuP) organic phase values were slightly higher and better. Slope analysis also indicated that the Fe(II) complexes extracted into both organic phases were Fe(BuEtP)o and Fe(HBuEtP)(BuP)o respectively
Effects of Different Concentrations of Biocides on Fungal Populations Isolated from Biofilms of Corroded Oil Pipelines
Microbiologically influenced corrosion is a problem commonly encountered in facilities in the oil and gas industries. The present study described fungal enumeration and identification in biofilms of oil pipelines in Oshie flow station in Rivers State and Irri flow station in Delta State, Nigeria using traditional cultivation technique. The fungal species isolated in biofilms from the two sites are as follows Verticillium dahlae, Saccharomyces cerevisiae, Penicillium corylophilum, Botrytis cinerea, Fusarium paradoxus, Aspergillus paradoxus, Humicola grisae, Aureobasidium pullulans, Monilia balanitis, Hormoconis resinea, Asperillus flavus and Helimenthosporium maydis. The study also focuses on the use of three biocides to inhibit or eliminate the identified organisms in order to minimize the material and financial losses encountered by oil and gas companies, because of microbiologically influenced corrosion (MIC). The performance of three biocides (ozone, sodium hypochlorite and formaldehyde) at the concentrations 0, 1, 2, 3, 4 and 5% in eliminating the fungal species isolated from biofilms of oil pipelines in Rivers and Delta States, Niger Delta, Nigeria. It is shown that formaldehyde an ozone exhibit the best biocidal characteristics and concentrations of 1 and 2 % eliminated all to almost the fungal species after 72 hours of contact time. This study is relevant to the problem of microbiologically influenced corrosion as the data may contribute to elucidate which fungal species contribute to the MIC process and to gain a better understanding of the fungal community of biofilms. This study will give us better understanding of the biocide capable of eliminating fungal species in biofilm of oil and gas pipelines. Key word: Concentration, fungal population, biocides, microbiologically influenced corrosion, biofilm
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The Impact of Gender on Domestic Human Rights Abuse
This study develops three models of human rights determinants with the inclusion an untested variable, women in parliaments. The research is conducted on pooled cross-sectional time-series data from 130 countries between 1978 and 1996. For the purpose of analysis the Prais-Winsten Regression method with Panel Corrected Standard Errors was used. The women in power variable is hypothesized to be significantly, positively correlated with a state's propensity toward respect for human rights and is operationalized as percentage of women in parliaments. Three models incorporating as control variables previously identified correlates of human rights abuse were utilized to asses the impact of percentages of women in parliaments on two individual subsets of human rights: personal integrity rights and socio-economic rights. Two models were designed to measure the subset of rights categorized as personal integrity rights using two separate measures: State Department Scores and Amnesty International Scores. Model number three utilized the Physical Quality of Life Index to measure levels of socio-economic rights. Statistical significance was demonstrated by the women in parliament variable in all three models
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