43 research outputs found
A Ricardian analysis of the climate change impact on Nepalese agriculture
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
A Ricardian analysis of the climate change impact on Nepalese agriculture
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
A Ricardian analysis of the climate change impact on Nepalese agriculture
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
Factors Influencing Food Insecurity in Nepal
Nepal has been persistently encountering food insecurity and under-nutrition. It is therefore utmost important to determine the factors responsible for influencing food insecurity in Nepal. This study examines the factors determining food insecurity in Nepal applying binary logistic models for food poverty, household with inadequate food consumption and poor dietary diversity using data from Nepal Living Standard Survey 2010/11. Food security was determined to be strongly associated with education level and age of household head, household with higher female education level, larger farm size with higher ratio of irrigated land, better access to markets, roads and cooperatives, better household assets and remittance recipient households. Food insecure is relatively more prevalent in rural areas with higher dependent on rain-fed agriculture, higher dependency ratio and larger family size. Improving both physical and economic access to foods, together with investment in education and agriculture could help to reduce food insecurity and hunger from Nepal
Determinants of Per Capita Food Expenditure to Assess Food Security Status of Nepal
Food security is the global issue as the Sustainable Development Goal (SDG) has explicitly considered zero hunger in the Goal 2. Nonetheless, in the recent years, the number of hunger population is in constant rise. Therefore, the paper attempts to estimate the determinants of the per capita food expenditure from the household expenditure. The data of National Living Standard Survey 2010/11 by the Central Bureau of Statistics Nepal has been used for the study. The multiple regression analysis has been performed. The per capita food expenditure has been used as the dependent variable. The model was found significant and the R-squared value was found 0.77. All the explanatory variables – except gender and education level (completed grade 5-7), were found significant. The number of households, area related variables urban rural and few development regions were found negatively associated with the per capita food expenditure
Primary Black Hole Spin in OJ 287 as Determined by the General Relativity Centenary Flare
OJ 287 is a quasi-periodic quasar with roughly 12 year optical cycles. It displays prominent outbursts that are predictable in a binary black hole model. The model predicted a major optical outburst in 2015 December. We found that the outburst did occur within the expected time range, peaking on 2015 December 5 at magnitude 12.9 in the optical R -band. Based on Swift /XRT satellite measurements and optical polarization data, we find that it included a major thermal component. Its timing provides an accurate estimate for the spin of the primary black hole, ##IMG## [http://ej.iop.org/images/2041-8205/819/2/L37/apjl523055ieqn1.gif] . The present outburst also confirms the established general relativistic properties of the system such as the loss of orbital energy to gravitational radiation at the 2% accuracy level, and it opens up the possibility of testing the black hole no-hair theorem with 10% accuracy during the present decade.Peer reviewe
Authenticating the Presence of a Relativistic Massive Black Hole Binary in OJ 287 Using Its General Relativity Centenary Flare : Improved Orbital Parameters
Results from regular monitoring of relativistic compact binaries like PSR 1913+16 are consistent with the dominant (quadrupole) order emission of gravitational waves (GWs). We show that observations associated with the binary black hole (BBH) central engine of blazar OJ 287 demand the inclusion of gravitational radiation reaction effects beyond the quadrupolar order. It turns out that even the effects of certain hereditary contributions to GW emission are required to predict impact flare timings of OJ 287. We develop an approach that incorporates this effect into the BBH model for OJ 287. This allows us to demonstrate an excellent agreement between the observed impact flare timings and those predicted from ten orbital cycles of the BBH central engine model. The deduced rate of orbital period decay is nine orders of magnitude higher than the observed rate in PSR 1913+16, demonstrating again the relativistic nature of OJ 287's central engine. Finally, we argue that precise timing of the predicted 2019 impact flare should allow a test of the celebrated black hole "no-hair theorem" at the 10% level.Peer reviewe
Global burden and strength of evidence for 88 risk factors in 204 countries and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021
Background: Understanding the health consequences associated with exposure to risk factors is necessary to inform public health policy and practice. To systematically quantify the contributions of risk factor exposures to specific health outcomes, the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 aims to provide comprehensive estimates of exposure levels, relative health risks, and attributable burden of disease for 88 risk factors in 204 countries and territories and 811 subnational locations, from 1990 to 2021. Methods: The GBD 2021 risk factor analysis used data from 54 561 total distinct sources to produce epidemiological estimates for 88 risk factors and their associated health outcomes for a total of 631 risk–outcome pairs. Pairs were included on the basis of data-driven determination of a risk–outcome association. Age-sex-location-year-specific estimates were generated at global, regional, and national levels. Our approach followed the comparative risk assessment framework predicated on a causal web of hierarchically organised, potentially combinative, modifiable risks. Relative risks (RRs) of a given outcome occurring as a function of risk factor exposure were estimated separately for each risk–outcome pair, and summary exposure values (SEVs), representing risk-weighted exposure prevalence, and theoretical minimum risk exposure levels (TMRELs) were estimated for each risk factor. These estimates were used to calculate the population attributable fraction (PAF; ie, the proportional change in health risk that would occur if exposure to a risk factor were reduced to the TMREL). The product of PAFs and disease burden associated with a given outcome, measured in disability-adjusted life-years (DALYs), yielded measures of attributable burden (ie, the proportion of total disease burden attributable to a particular risk factor or combination of risk factors). Adjustments for mediation were applied to account for relationships involving risk factors that act indirectly on outcomes via intermediate risks. Attributable burden estimates were stratified by Socio-demographic Index (SDI) quintile and presented as counts, age-standardised rates, and rankings. To complement estimates of RR and attributable burden, newly developed burden of proof risk function (BPRF) methods were applied to yield supplementary, conservative interpretations of risk–outcome associations based on the consistency of underlying evidence, accounting for unexplained heterogeneity between input data from different studies. Estimates reported represent the mean value across 500 draws from the estimate's distribution, with 95% uncertainty intervals (UIs) calculated as the 2·5th and 97·5th percentile values across the draws. Findings: Among the specific risk factors analysed for this study, particulate matter air pollution was the leading contributor to the global disease burden in 2021, contributing 8·0% (95% UI 6·7–9·4) of total DALYs, followed by high systolic blood pressure (SBP; 7·8% [6·4–9·2]), smoking (5·7% [4·7–6·8]), low birthweight and short gestation (5·6% [4·8–6·3]), and high fasting plasma glucose (FPG; 5·4% [4·8–6·0]). For younger demographics (ie, those aged 0–4 years and 5–14 years), risks such as low birthweight and short gestation and unsafe water, sanitation, and handwashing (WaSH) were among the leading risk factors, while for older age groups, metabolic risks such as high SBP, high body-mass index (BMI), high FPG, and high LDL cholesterol had a greater impact. From 2000 to 2021, there was an observable shift in global health challenges, marked by a decline in the number of all-age DALYs broadly attributable to behavioural risks (decrease of 20·7% [13·9–27·7]) and environmental and occupational risks (decrease of 22·0% [15·5–28·8]), coupled with a 49·4% (42·3–56·9) increase in DALYs attributable to metabolic risks, all reflecting ageing populations and changing lifestyles on a global scale. Age-standardised global DALY rates attributable to high BMI and high FPG rose considerably (15·7% [9·9–21·7] for high BMI and 7·9% [3·3–12·9] for high FPG) over this period, with exposure to these risks increasing annually at rates of 1·8% (1·6–1·9) for high BMI and 1·3% (1·1–1·5) for high FPG. By contrast, the global risk-attributable burden and exposure to many other risk factors declined, notably for risks such as child growth failure and unsafe water source, with age-standardised attributable DALYs decreasing by 71·5% (64·4–78·8) for child growth failure and 66·3% (60·2–72·0) for unsafe water source. We separated risk factors into three groups according to trajectory over time: those with a decreasing attributable burden, due largely to declining risk exposure (eg, diet high in trans-fat and household air pollution) but also to proportionally smaller child and youth populations (eg, child and maternal malnutrition); those for which the burden increased moderately in spite of declining risk exposure, due largely to population ageing (eg, smoking); and those for which the burden increased considerably due to both increasing risk exposure and population ageing (eg, ambient particulate matter air pollution, high BMI, high FPG, and high SBP). Interpretation: Substantial progress has been made in reducing the global disease burden attributable to a range of risk factors, particularly those related to maternal and child health, WaSH, and household air pollution. Maintaining efforts to minimise the impact of these risk factors, especially in low SDI locations, is necessary to sustain progress. Successes in moderating the smoking-related burden by reducing risk exposure highlight the need to advance policies that reduce exposure to other leading risk factors such as ambient particulate matter air pollution and high SBP. Troubling increases in high FPG, high BMI, and other risk factors related to obesity and metabolic syndrome indicate an urgent need to identify and implement interventions
Authenticating the Presence of a Relativistic Massive Black Hole Binary in OJ 287 Using Its General Relativity Centenary Flare: Improved Orbital Parameters
© 2018. The American Astronomical Society. All rights reserved. Results from regular monitoring of relativistic compact binaries like PSR 1913+16 are consistent with the dominant (quadrupole) order emission of gravitational waves (GWs). We show that observations associated with the binary black hole (BBH) central engine of blazar OJ 287 demand the inclusion of gravitational radiation reaction effects beyond the quadrupolar order. It turns out that even the effects of certain hereditary contributions to GW emission are required to predict impact flare timings of OJ 287. We develop an approach that incorporates this effect into the BBH model for OJ 287. This allows us to demonstrate an excellent agreement between the observed impact flare timings and those predicted from ten orbital cycles of the BBH central engine model. The deduced rate of orbital period decay is nine orders of magnitude higher than the observed rate in PSR 1913+16, demonstrating again the relativistic nature of OJ 287's central engine. Finally, we argue that precise timing of the predicted 2019 impact flare should allow a test of the celebrated black hole "no-hair theorem" at the 10% level