4,258 research outputs found
Impact of Income on Calorie and Nutrient Intakes: A Cross-Country Analysis
The relationship between income and nutrient intake is explored. Nonparametric, panel, and quantile regressions are used. Engle curves for calories, fat, and protein are approximately linear in logs with carbohydrate intakes exhibiting diminishing elasticities as incomes increase. Elasticities range from 0.10 to 0.25, with fat having the highest elasticities. Countries in higher quantiles have lower elasticities than those in lower quantiles. Results predict significant cumulative increases in calorie consumption which are increasingly composed of fats. Though policies aimed at poverty alleviation and economic growth may assuage hunger and malnutrition, they may also exacerbate problems associated with obesity.calorie and nutrient consumption, food and nutrition policy, income elasticities, nonparametric, panel, quantile regression., Agricultural and Food Policy, Food Consumption/Nutrition/Food Safety, Food Security and Poverty, International Development, Research Methods/ Statistical Methods, C11, C14, C21, C23, O10, O47, Q18,
Integrating spatial dependence into stochastic frontier analysis
An approach to incorporate spatial dependence into Stochastic Frontier analysis is developed and applied to a sample of 215 dairy farms in England and Wales. A number of alternative specifications for the spatial weight matrix are used to analyse the effect of these on the estimation of spatial dependence. Estimation is conducted using a Bayesian approach and results indicate that spatial dependence is present when explaining technical inefficiency.Spatial dependence, technical efficiency, Bayesian, spatial weight matrix
Provision of an environmental output within a multi-output distance function approach
This paper redefines technical efficiency by incorporating provision of environmental goods as one of the outputs of the farm within a multi-outptut distance function framework. Permanent and rough grassland area are used as a proxy for the provision of environmental goods. The multi-output distance function approach is used to estimate technical efficiency. A Bayesian procedure involving the use of a Gibbs sampler is used to estimate the farm specific efficiency as well as the coefficients of the distance function. In addition, a number of explanatory variables for the efficiency were introduced in the analysis and posterior distributions of those were obtained. The methodology is applied to panel data on 215 dairy farms in England and Wales from the Defra Farm Business Survey. Results show that both farm efficiency rankings and determinants of inefficiency change when provision of environmental outputs by farms is incorporated in the efficiency analysis, which may have important political implications.Technical efficiency, environmental good, multi-output
Dark energy effects in the Schr\"odinger-Newton approach
The Schr\"odinger-Newton equation is a proposed model to explain the
localization of macroscopic particles by suppressing quantum dispersion with
the particle's own gravitational attraction. On cosmic scales, however, dark
energy also acts repulsively, as witnessed by the accelerating rate of
universal expansion. Here, we introduce the effects of dark energy in the form
of a cosmological constant , that drives the late-time acceleration of
the Universe, into the Schr\"odinger-Newton approach. We then ask in which
regime dark energy dominates both canonical quantum diffusion and gravitational
self-attraction. It turns out that this happens for sufficiently delocalized
objects with an arbitrary mass and that there exists a minimal delocalization
width of about m. While extremely macroscopic from a quantum perspective,
the value is in principle accessible to laboratories on Earth. Hence, we
analyze, numerically, how the dynamics of an initially spherical Gaussian wave
packet is modified in the presence of . A notable feature is the
gravitational collapse of part of the wave packet, in the core region close to
the center of mass, accompanied by the accelerated expansion of the more
distant shell surrounding it. The order of magnitude of the distance separating
collapse from expansion matches analytical estimates of the classical
turnaround radius for a spherically symmetric body in the presence of dark
energy. However, the time required to observe these modifications is
astronomical. They can potentially be measured only in physical systems
simulating a high effective cosmological constant, or, possibly, via their
effects on the inflationary universe.Comment: 8 pages, 4 figures, 2 appendices. Published versio
Mass Additivity and A Priori Entailment
The principle of mass additivity states that the mass of a composite object
is the sum of the masses of its elementary components. Mass additivity is true
in Newtonian mechanics but false in special relativity. Physicists have
explained why mass additivity is true in Newtonian mechanics by reducing it to
Newton's microphysical laws. This reductive explanation does not fit well with
deducibility theories of reductive explanation such as the modern Nagelian
theory of reduction, and the a priori entailment theory of reduction that is
prominent in the philosophy of mind. Nonetheless, I argue that a reconstruction
of the explanation that incorporates distinctively philosophical concepts in
fact fits both theories. I discuss the implications of this result for both
theories and for the reductive explanation of consciousness
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Realising the therapeutic potential of neuroactive steroid modulators of the GABA<sub>A</sub> receptor
In the 1980s particular endogenous metabolites of progesterone and of deoxycorticosterone were revealed to be potent, efficacious, positive allosteric modulators (PAMs) of the GABAA receptor (GABAAR). These reports were followed by the discovery that such steroids may be synthesised not only in peripheral endocrine glands, but locally in the central nervous system (CNS), to potentially act as paracrine, or autocrine "neurosteroid" messengers, thereby fine tuning neuronal inhibition. These discoveries triggered enthusiasm to elucidate the physiological role of such neurosteroids and explore whether their levels may be perturbed in particular psychiatric and neurological disorders. In preclinical studies the GABAAR-active steroids were shown to exhibit anxiolytic, anticonvulsant, analgesic and sedative properties and at relatively high doses to induce a state of general anaesthesia. Collectively, these findings encouraged efforts to investigate the therapeutic potential of neurosteroids and related synthetic analogues. However, following over 30 years of investigation, realising their possible medical potential has proved challenging. The recent FDA approval for the natural neurosteroid allopregnanolone (brexanolone) to treat postpartum depression (PPD) should trigger renewed enthusiasm for neurosteroid research. Here we focus on the influence of neuroactive steroids on GABA-ergic signalling and on the challenges faced in developing such steroids as anaesthetics, sedatives, analgesics, anticonvulsants, antidepressants and as treatments for neurodegenerative disorders
Information erasure without an energy cost
Landauer argued that the process of erasing the information stored in a
memory device incurs an energy cost in the form of a minimum amount of
mechanical work. We find, however, that this energy cost can be reduced to zero
by paying a cost in angular momentum or any other conserved quantity. Erasing
the memory of Maxwell's demon in this way implies that work can be extracted
from a single thermal reservoir at a cost of angular momentum and an increase
in total entropy. The implications of this for the second law of thermodynamics
are assessed.Comment: 8 pages with 1 figure. Final published versio
Four Tails Problems for Dynamical Collapse Theories
The primary quantum mechanical equation of motion entails that measurements typically do not have determinate outcomes, but result in superpositions of all possible outcomes. Dynamical collapse theories (e.g. GRW) supplement this equation with a stochastic Gaussian collapse function, intended to collapse the superposition of outcomes into one outcome. But the Gaussian collapses are imperfect in a way that leaves the superpositions intact. This is the tails problem. There are several ways of making this problem more precise. But many authors dismiss the problem without considering the more severe formulations. Here I distinguish four distinct tails problems. The first (bare tails problem) and second (structured tails problem) exist in the literature. I argue that while the first is a pseudo-problem, the second has not been adequately addressed. The third (multiverse tails problem) reformulates the second to account for recently discovered dynamical consequences of collapse. Finally the fourth (tails problem dilemma) shows that solving the third by replacing the Gaussian with a non-Gaussian collapse function introduces new conflict with relativity theory
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