397 research outputs found

    A Ricardian analysis of the climate change impact on Nepalese agriculture

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    This paper applies Ricardian approach to measure the effect of climate change on crop production in Nepal using cross-section data of Nepal Living Standard Survey 2003/04 and climate data from Department of Hydrology and Meteorology, Nepal. The study examines the relationship between net farm revenue and climate variables using 656 households of 14 districts covering all climatic zones of Nepal. Net farm revenue is regressed on climate and socio-economic variables. The findings show that these variables have significant impact on the net farm value per hectare. More specifically, relatively low precipitation and high temperature seem to have positive impact on net farm income during the fall and spring seasons. Net farm income is likely to be increased by summer precipitation, but not by temperature. Marginal impacts are mostly in line with the Ricardian model, showing marginally increasing precipitation during summer and winter would increase net farm income, but reduce by the quarter terms and temperature of these seasons. Moreover, marginally increasing precipitation would increase farm income in the hilly region, but reduce in Terai region. Other variables such as ratio of irrigated farm land and obtaining credit are found to be positive impact on net farm value but not by farm size. Conclusively, the impact of climate change on agriculture seems to be varied with the temperature and precipitation in different climatic zones.climate change, agriculture, Ricardian approach, marginal impact, Nepal

    Accurate Regression Test Cases Generation in Live Build Routines

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    Regression testing is typically performed after changing the code of a software program or system. Identifying the relevant regression tests to be performed to test all of the code changes is difficult, and usually a manual process. A technique is disclosed that automatically identifies and selects an optimal set of test cases to cover the impact of changes in the code base

    Management of Biochemical Recurrence after Primary Localized Therapy for Prostate Cancer

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    Clinically localized prostate cancer is typically managed by well established therapies like radical prostatectomy, brachytherapy, and external beam radiation therapy. While many patients can be cured with definitive local therapy, some will have biochemical recurrence (BCR) of disease detected by a rising serum prostate-specific antigen (PSA). Management of these patients is nuanced and controversial. The natural history indicates that a majority of patients with BCR will not die from prostate cancer but from other causes. Despite this, a vast majority of patients with BCR are empirically treated with non-curable systemic androgen deprivation therapy (ADT), with its myriad of real and potential side effects. In this review article, we examined the very definition of BCR after definitive local therapy, the current status of imaging studies in its evaluation, the need for additional therapies, and the factors involved in the decision making in the choice of additional therapies. This review aims to help clinicians with the management of patients with BCR. The assessment of prognostic factors including absolute PSA level, time to recurrence, PSA kinetics, multivariable nomograms, imaging, and biopsy of the prostatic bed may help stratify the patients into localized or systemic recurrence. Patients with low-risk of systemic disease may be cured by a salvage local therapy, while those with higher risk of systemic disease may be offered the option of ADT or a clinical trial. An algorithm incorporating these factors is presented

    Nature of reactive O2 and slow CO2 evolution kinetics in CO oxidation by TiO2 supported Au cluster

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    Journal ArticleRecent experiments on CO oxidation reaction using seven-atom Au clusters deposited on TiO2 surface correlate CO2 formation with oxygen associated with Au clusters. We perform first principles calculations using a seven-atom Au cluster supported on a reduced TiO2 surface to explore potential candidates for the form of reactive oxygen. These calculations suggest a thermodynamically favorable path for O2 diffusion along the surface Ti row, resulting in its dissociated state bound to Au cluster and TiO2 surface. CO can approach along the same path and react with the O2 so dissociated to form CO2. The origin of the slow kinetic evolution of products observed in experiments is also investigated and is attributed to the strong binding of CO2 simultaneously to the Au cluster and the surface

    Critical epinucleation on reconstructured surfaces and first-principle calculation of homonucleation on Si(100)

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    Journal ArticleWe introduce the concept of ‘‘critical epinucleation'' to distinguish nucleation on surfaces with and without reconstruction. On a reconstructed surface, the critical classical nucleus is stable against dissociation, but may not yet break the underlying surface reconstruction. Consequently, there must exist a ‘‘critical epinucleus'' that is not only stable but also has established the epiconfiguration by unreconstructing the underlying substrate. We illustrate this concept by first-principle calculation of homonucleation on reconstructed Si(001) surface where the critical epinucleus consists of six adatoms

    Lymphadenectomy in Management of Invasive Bladder Cancer

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    Radical cystectomy with pelvic lymphadenectomy represents the gold standard for treatment of muscle-invasive bladder cancer. Extent of the lymph node dissection and lymph node involvement during radical cystectomy are the most powerful prognostic factors associated with poor oncological outcome. However, the optimal boundaries of the lymph node dissection during a radical cystectomy are controversial. The published literature based mostly on retrospective studies suggests that increasing the number of nodes excised may have therapeutic and diagnostic benefits without significantly increasing the surgical morbidity. These conclusions are, however, influenced by selection and surgeon biases, inconsistencies in the quality of the surgery, and node count variability. In this paper, we establish the current understanding about the utility of lymphadenectomy during a radical cystectomy for muscle-invasive bladder cancer

    Determining the adsorptive and catalytic properties of strained metal surfaces using adsorption-induced stress

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    Journal ArticleWe demonstrate a model for determining the adsorptive and catalytic properties of strained metal surfaces based on linear elastic theory, using first-principles calculations of CO adsorption on Au and K surfaces and CO dissociation on Ru surface. The model involves a single calculation of the adsorption-induced surface stress on the unstrained metal surface, which determines quantitatively how adsorption energy changes with external strain. The model is generally applicable to both transition- and non-transition-metal surfaces, as well as to different adsorption sites on the same surface. Extending the model to both the reactant and transition state of surface reactions should allow determination of the effect of strain on surface reactivity
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