2,548 research outputs found

    Energy poverty in rural and urban India : are the energy poor also income poor ?

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    Energy poverty is a frequently used term among energy specialists, but unfortunately the concept is rather loosely defined. Several existing approaches measure energy poverty by defining an energy poverty line as the minimum quantity of physical energy neededto perform such basic tasks as cooking and lighting. This paper proposes an alternative measure that is based on energy demand. The energy poverty line is defined as the threshold point at which energy consumption begins to rise with increases in household income. This approach was applied to cross-sectional data from a comprehensive 2005 household survey representative of both urban and rural India. The findings suggest that in rural areas some 57 percent of households are energy poor, versus 22 percent that are income poor. For urban areas the energy poverty rate is 28 percent compared with 20 percent that are income poor. Policies to reduce energy poverty would include support for rural electrification, the promotion of more modern cooking fuels, and encouraging greater adoption of improved biomass stoves. A combination of these programs would play a significant role in reducing energy poverty in rural India.Energy Production and Transportation,Rural Poverty Reduction,Energy and Environment,Environment and Energy Efficiency,Energy Demand

    Welfare impacts of rural electrification : a case study from Bangladesh

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    Lack of access to electricity is one of the major impediments to growth and development of the rural economies in developing countries. That is why access to modern energy, in particular to electricity, has been one of the priority themes of the World Bank and other development organizations. Using a cross-sectional survey conducted in 2005 of some 20,000 households in rural Bangladesh, this paper studies the welfare impacts of households'grid connectivity. Based on rigorous econometric estimation techniques, this study finds that grid electrification has significant positive impacts on households'income, expenditure, and educational outcomes. For example, the gain in total income due to electrification can be as much as 30 percent and as low as 9 percent. Benefits go up steadily as household exposure to grid electrification (measured by duration) increases and eventually reach a plateau. This paper also finds that rich households benefit more from electrification than poor households. Finally, estimates also show that income benefits of electrification on an average exceed cost by a wide margin.Energy Production and Transportation,Access to Finance,Engineering,Electric Power,Rural Poverty Reduction

    Welfare impacts of rural electrification : evidence from Vietnam

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    Access to electricity is crucial for economic development and there is a growing body of literature on the impact of rural electrification on development. However, most studies have so far relied on cross-sectional surveys comparing households with and without electricity, which have well known causal attribution problems. This paper is one of the first studies to examine the welfare impacts of households’ rural electrification based on panel surveys conducted in 2002 and 2005 for some 1,100 households in rural Vietnam,. The findings indicate that grid electrification has been both extensive (connecting all surveyed communes by 2005) and intensive (connecting almost 80 percent of the surveyed households by 2005). Vietnam is unusual in that once electricity is locally available, both rich and poor households are equally likely to get the connection. The econometric estimations suggest that grid electrification has significant positive impacts on households’ cash income, expenditure, and educational outcomes. The benefits, however, reach a saturation point after prolonged exposure to electricity. Finally, this study recommends investigating the long-term benefits of rural electrification - not just for households, but for the rural economy as a whole.Energy Production and Transportation,Electric Power,Engineering,Access to Finance,Rural Poverty Reduction

    Nurses\u27 and Patients\u27 Appraisals Show Patient Safety in Hospitals Remains a Concern

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    In the report To Err is Human (1999), the National Academy of Medicine called for national action to improve patient safety in hospitals. The report concluded that improving nurse work environments—assuring adequate nurse staffing and supporting nurses’ ability to care for patients—was critical to these efforts. Two decades later, have nurse work environments improved, and has that had a noticeable impact on patient safety? To find out, a research team led by LDI Senior Fellow Linda Aiken, PhD, RN surveyed more than 800,000 patients and 53,000 nurses in 535 hospitals in 2005, and again in 2016

    Spin dynamics of SrCu2_2O3_3 and the Heisenberg ladder

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    The S=1/2S=1/2 Heisenberg antiferromagnet in the ladder geometry is studied as a model for the spin degrees of freedom of SrCu2_2O3_3. The susceptibility and the spin echo decay rate are calculated using a quantum Monte Carlo technique, and the spin-lattice relaxation rate is obtained by maximum entropy analytic continuation of imaginary time correlation functions. All calculated quantities are in reasonable agreement with experimental results for SrCu2_2O3_3 if the exchange coupling J≈850J \approx 850K, i.e. significantly smaller than in high-Tc_c cuprates.Comment: 11 pages (Revtex) + 3 uuencoded ps files. To appear in Phys. Rev. B, Rapid Com

    Rotation of planet-harbouring stars

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    The rotation rate of a star has important implications for the detectability, characterisation and stability of any planets that may be orbiting it. This chapter gives a brief overview of stellar rotation before describing the methods used to measure the rotation periods of planet host stars, the factors affecting the evolution of a star's rotation rate, stellar age estimates based on rotation, and an overview of the observed trends in the rotation properties of stars with planets.Comment: 16 pages, 4 figures: Invited review to appear in 'Handbook of Exoplanets', Springer Reference Works, edited by Hans J. Deeg and Juan Antonio Belmont

    Transit Timing Observations from Kepler: VII. Confirmation of 27 planets in 13 multiplanet systems via Transit Timing Variations and orbital stability

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    We confirm 27 planets in 13 planetary systems by showing the existence of statistically significant anti-correlated transit timing variations (TTVs), which demonstrates that the planet candidates are in the same system, and long-term dynamical stability, which places limits on the masses of the candidates---showing that they are planetary. %This overall method of planet confirmation was first applied to \kepler systems 23 through 32. All of these newly confirmed planetary systems have orbital periods that place them near first-order mean motion resonances (MMRs), including 6 systems near the 2:1 MMR, 5 near 3:2, and one each near 4:3, 5:4, and 6:5. In addition, several unconfirmed planet candidates exist in some systems (that cannot be confirmed with this method at this time). A few of these candidates would also be near first order MMRs with either the confirmed planets or with other candidates. One system of particular interest, Kepler-56 (KOI-1241), is a pair of planets orbiting a 12th magnitude, giant star with radius over three times that of the Sun and effective temperature of 4900 K---among the largest stars known to host a transiting exoplanetary system.Comment: 12 pages, 13 figures, 5 tables. Submitted to MNRA

    Kinematic properties of early-type galaxy haloes using planetary nebulae

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    We present new planetary nebulae (PNe) positions, radial velocities, and magnitudes for 6 early-type galaxies obtained with the Planetary Nebulae Spectrograph, their two-dimensional velocity and velocity dispersion fields. We extend this study to include an additional 10 early-type galaxies with PNe radial velocity measurements available from the literature, to obtain a broader description of the outer-halo kinematics in early-type galaxies. These data extend the information derived from stellar kinematics to typically up to ~8 Re. The combination of photometry, stellar and PNe kinematics shows: i) good agreement between the PNe number density and the stellar surface brightness in the region where the two data sets overlap; ii) good agreement between PNe and stellar kinematics; iii) that the mean rms velocity profiles fall into two groups: with of the galaxies characterized by slowly decreasing profiles and the remainder having steeply falling profiles; iv) a larger variety of velocity dispersion profiles; v) that twists and misalignments in the velocity fields are more frequent at large radii, including some fast rotators; vi) that outer haloes are characterised by more complex radial profiles of the specific angular momentum-related lambda_R parameter than observed within 1Re; vii) that many objects are more rotationally dominated at large radii than in their central parts; and viii) that the halo kinematics are correlated with other galaxy properties, such as total luminosity, isophotal shape, total stellar mass, V/sigma, and alpha parameter, with a clear separation between fast and slow rotators.Comment: 36 pages, 21 figures, revised version for MNRA

    Dark Stars and Boosted Dark Matter Annihilation Rates

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    Dark Stars (DS) may constitute the first phase of stellar evolution, powered by dark matter (DM) annihilation. We will investigate here the properties of DS assuming the DM particle has the required properties to explain the excess positron and elec- tron signals in the cosmic rays detected by the PAMELA and FERMI satellites. Any possible DM interpretation of these signals requires exotic DM candidates, with an- nihilation cross sections a few orders of magnitude higher than the canonical value required for correct thermal relic abundance for Weakly Interacting Dark Matter can- didates; additionally in most models the annihilation must be preferentially to lep- tons. Secondly, we study the dependence of DS properties on the concentration pa- rameter of the initial DM density profile of the halos where the first stars are formed. We restrict our study to the DM in the star due to simple (vs. extended) adiabatic contraction and minimal (vs. extended) capture; this simple study is sufficient to illustrate dependence on the cross section and concentration parameter. Our basic results are that the final stellar properties, once the star enters the main sequence, are always roughly the same, regardless of the value of boosted annihilation or concentration parameter in the range between c=2 and c=5: stellar mass ~ 1000M\odot, luminosity ~ 10^7 L\odot, lifetime ~ 10^6 yrs (for the minimal DM models considered here; additional DM would lead to more massive dark stars). However, the lifetime, final mass, and final luminosity of the DS show some dependence on boost factor and concentration parameter as discussed in the paper.Comment: 37 pages, 11 figure
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