1,142 research outputs found

    Household Projections for Rural and Urban Areas of Major Regions of the World

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    Demographic dynamics are important drivers of environmental change, including effects on climate through energy and land use that lead to emissions of greenhouse gases. These dynamics include changes to population size, age structure, and urbanization, as well as changes in household living arrangements. Population and household projections are therefore essential for investigating potential future demographic effects, but no long-term, global projections exist that simultaneously describe consistent outcomes for population, urbanization, and households. We therefore develop a new set of population/household projections for nine world regions. The projections are based partly on existing population and urbanization projections, partly on new multi-state projections for China and India, and on a new household projection using age-, size-, and urban/rural-specific headship rates. We discuss principle results that foresee future aging, urbanization, and trends toward smaller household sizes

    Impacts of Demographic Events on US Household Change

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    Understanding the determinants and consequences of changes in household size and structure is important to a wide range of social, economic, and environmental issues. In the U.S., living arrangements have undergone tremendous changes over the past 200+ years, but have been relatively stable since 1980. What drove these changes, and whether the recent stability can be expected to continue, are critical questions. While research has identified demographic events that drive particular types of changes in households, a systematic understanding of past and potential future changes is lacking. We use a household projection model to assess the sensitivity of household size and structure to various demographic events, and show that outcomes are most sensitive to changes in fertility rates and union formation and dissolution rates. They are less sensitive to the timing of marriage and childbearing and to changes in life expectancy. We then construct a set of future scenarios designed to reflect a wide but plausible range of outcomes, including a new set of scenarios for union formation and dissolution rates based on past trends, experience in other countries, and current theory. We find that the percentage of people living in households headed by the elderly may climb from 11% in 2000 to 20-31% in 2050 and 20-39% in 2100, while the average size of households could plausibly be as low as 2.0 or as high as 3.1 by the second half of the century

    Projecting U.S. Household Changes with a New Household Model

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    Anticipating changes in number, size, and composition of households is an important element of many issues of social concern. To facilitate continued progress in these areas, an efficient household projection model with moderate data requirements, manageable complexity, explicit accounting for the effects of demographic events, and output that includes the most important household characteristics is needed. None of the existing modelling approaches meets all these needs. This study proposes a new type of headship rate model that projects changes in age- and size-specific headship rates by accounting for the effect of changes in population age structure, changes in the age structure of household heads, and the effect of demographic events. We compare model results to historical data on the last 100 years of experience in the United United States, and to results from a projection over the next 100 years using the dynamic household model ProFamy. Results show that the new model is a substantial improvement over the commonly used constant headship rate approach. A simplified version of the model that does not require projecting the effect of changes in demographic events on headship rates appears to produce reasonably accurate projections of the composition of the population by household size and age of the household head

    Household Survey Data Used in Calibrating the Population-Environment-Technology Model

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    The Population-Environment-Technology (PET) model is an inter-temporal general equilibrium model of global scale used to project future energy demand and related CO2 emissions. It can include multiple production and consumption sectors and is well suited to incorporate a heterogeneous population structure. Calibration of general equilibrium models is usually very data intensive. In this report we present the data used in the calibration of the household side of the PET model. We include a description of the household surveys, the process of analyzing both income and consumption data, and a few illustratve results of variations in household characteristics across regions and household types

    Population Aging and Future Carbon Emissions in the United States

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    Changes in the age composition of U.S. households over the next several decades could affect energy use and carbon dioxide emissions. this article incorporates population age structure into and energy-economic growth model with multiple dynasties of heterogenous households. The model is used to estimate and compare effects of population aging and technical change on baseline paths of U.S. energy use and emissions. Results show that population aging reduces long-term carbon dioxide emissions, by almost 40% in low population scenario, and effects of aging on emissions can be as large, or larger than effects of technical change in some cases

    Role of additives in electrochemical deposition of ternary metal oxide microspheres for supercapacitor applications

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    A simple two-step approach has been employed to synthesize a cobalt–nickel–copper ternary metal oxide, involving electrochemical precipitation/deposition followed by calcination. The ternary metal hydroxide gets precipitated/deposited from a nitrate bath at the cathode in the catholyte chamber of a two-compartment diaphragm cell at room temperature having a pH ≈ 3. The microstructure of the ternary hydroxides was modified in situ by two different surfactants such as cetyltrimethylammonium bromide and dodecyltrimethylammonium bromide in the bath aiming for enhanced storage performance in the electrochemical devices. The effect of the surfactant produces a transition from microspheres to nanosheets, and the effect of micelle concentration produces nanospheres at a higher ion concentration. The ternary hydroxides were calcined at 300 °C to obtain the desired ternary mixed oxide materials as the electrode for hybrid supercapacitors. X-ray diffraction analysis confirmed the formation of the ternary metal oxide product. The scanning electron microscopy images associated with energy-dispersive analysis suggest the formation of a nanostructured porous composite. Ternary metal oxide in the absence and presence of a surfactant served as the cathode and activated carbon served as the anode for supercapacitor application. DTAB-added metal oxide showed 95.1% capacitance retention after 1000 cycles, achieving 188 F/g at a current density of 0.1 A/g, and thereafter stable until 5000 cycles, inferring that more transition metals in the oxide along with suitable surfactants at an appropriate micellar concentration may be better for redox reactions and achieving higher electrical conductivity and smaller charge transfer resistance. The role of various metal cations and surfactants as additives in the electrolytic bath has been discussed

    Flavor Twisted Boundary Conditions, Pion Momentum, and the Pion Electromagnetic Form Factor

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    We investigate the utility of partially twisted boundary conditions in lattice calculations of meson observables. For dynamical simulations, we show that the pion dispersion relation is modified by volume effects. In the isospin limit, we demonstrate that the pion electromagnetic form factor can be computed on the lattice at continuous values of the momentum transfer. Furthermore, the finite volume effects are under theoretical control for extraction of the pion charge radius.Comment: 15 pages, 8 figures, revisions to text, refs adde

    Electroweak Supersymmetry around the Electroweak Scale

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    Inspired by the phenomenological constraints, LHC supersymmetry and Higgs searches, dark matter search as well as string model building, we propose the electroweak supersymmetry around the electroweak scale: the squarks and/or gluinos are around a few TeV while the sleptons, sneutrinos, bino and winos are within one TeV. The Higgsinos can be either heavy or light. We consider bino as the dominant component of dark matter candidate, and the observed dark matter relic density is achieved via the neutralino-stau coannihilations. Considering the Generalized Minimal Supergravity (GmSUGRA), we show explicitly that the electroweak supersymmetry can be realized, and the gauge coupling unification can be preserved. With two Scenarios, we study the viable parameter spaces that satisfy all the current phenomenological constraints, and we present the concrete benchmark points. Furthermore, we comment on the fine-tuning problem and LHC searches.Comment: RevTex4, 28 pages, 8 figures, 8 tables, version to appear in EPJ

    Stationary State Solutions of a Bond Diluted Kinetic Ising Model: An Effective-Field Theory Analysis

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    We have examined the stationary state solutions of a bond diluted kinetic Ising model under a time dependent oscillating magnetic field within the effective-field theory (EFT) for a honeycomb lattice (q=3)(q=3). Time evolution of the system has been modeled with a formalism of master equation. The effects of the bond dilution, as well as the frequency (ω)(\omega) and amplitude (h/J)(h/J) of the external field on the dynamic phase diagrams have been discussed in detail. We have found that the system exhibits the first order phase transition with a dynamic tricritical point (DTCP) at low temperature and high amplitude regions, in contrast to the previously published results for the pure case \cite{Ling}. Bond dilution process on the kinetic Ising model gives rise to a number of interesting and unusual phenomena such as reentrant phenomena and has a tendency to destruct the first-order transitions and the DTCP. Moreover, we have investigated the variation of the bond percolation threshold as functions of the amplitude and frequency of the oscillating field.Comment: 8 pages, 4 figure

    Meson Screening Mass in a Strongly Coupled Pion Superfluid

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    We calculate the meson screening mass in a pion superfluid in the framework of Nambu--Jona-Lasinio model. The minimum of the attractive quark potential is always located at the phase boundary of pion superfluid. Different from the temperature and baryon density effect, the potential at finite isospin density can not be efficiently suppressed and the matter is always in a strongly coupled phase due to the Goldstone mode in the pion superfluid.Comment: 8 pages, 7 figures(Accepted by European Physical Journal C
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