11,374 research outputs found
The relationship between noise and annoyance around Orly
The extent to which annoyance estimated by an isopsophic index is a good forecaster for annoyance perceived near airport approaches was investigated. An index of sensed annoyance is constructed, and the relationship between the annoyance index and the isopsophic index is studied
Culture and Development: An Analytical Framework
This paper develops a framework which analyzes how a population's culture affects the decisions of rational profit maximizing firms, while simultaneously exploring how the actions of these firms in turn affect the population's culture.By endogenizing culture as well as the more usual economic variables, it shows how an economically valuablebehavioural trait can be sustained as part of a competitive equilibrium.It is shown that, for given primitives, an economy can be in either a 'good' steady state, in which the valuable cultural trait is present, or a welfare dominated 'bad' one in which the valuable cultural trait disappears.Starting from the 'good' steady state and implementing productivity improvements raises welfare, but if changes are too rapid this steady state will not be reached from the old one.Instead, the unique trajectory is to the bad steady state where welfare is reduced.culture;development;inequality;technological change
Contracting Productivity Growth
In this paper, we analyze the interactions between growth and the contracting environment in the production sector.Allowing incompleteness in contracting implies that viable production relationships for firms and workers, and therefore the profitability of industries, depend on the rates of innovation and growth.The speed at which new innovations arrive in turn depends on the profitability of production, for the usual reasons examined in the endogenous growth literature.We show that these interactions can have important implications which are consistent with observed phenomena in both the micro and macro environment.In particular, we demonstrate that a technological shock (increasing productivity of research) can, through this interaction, lead to a productivity slowdown and a shift in labor market contracts away from firms providing implicit guarantees of lifetime employment and towards shorter-term "contractor" type arrangements.We show the consistency of an increase in the proportion of the labor force under short term employment, increased relative returns of workers in high productivity sectors, and increased income inequality, with a productivity slowdown of finite duration.economic growth;contracts;productivity
Trust, Social Capital and Economic Development
Many argue that elements of a society s norms, culture or social capital are central to understanding its development.However, these notions have been difficult to capture in economic models.Here we argue that trustworthiness is the economically relevant component of a society s culture and hence comprises its social capital.Individuals are trustworthy when they perform actions they have promised, even if these do not maximize their payoffs.The usual focus on incentive structures in motivating behaviour plays no role here.Instead, we emphasize more deep-seated modes of behaviour and consider that trustworthy agents are socialized to act as they do.To model this socialization, we borrow from a relatively new process of preference evolution pioneered by Bisin and Verdier (2001).The model developed endogenously accounts for social capital and explores its role in the process of economic development.It captures in a simple, formal way the interaction between social capital and the economy s productive process.The results obtained caution against rapid reform, provide an explanation for why late developing countries cannot easily transplant the modes of production that have proved useful in the West, and suggest an explanation for the pattern of reform experiences in ex-communist countries.technological change;public finance;economic development
Initial data for black hole-neutron star binaries: a flexible, high-accuracy spectral method
We present a new numerical scheme to solve the initial value problem for
black hole-neutron star binaries. This method takes advantage of the
flexibility and fast convergence of a multidomain spectral representation of
the initial data to construct high-accuracy solutions at a relatively low
computational cost. We provide convergence tests of the method for both
isolated neutron stars and irrotational binaries. In the second case, we show
that we can resolve the small inconsistencies that are part of the
quasi-equilibrium formulation, and that these inconsistencies are significantly
smaller than observed in previous works. The possibility of generating a wide
variety of initial data is also demonstrated through two new configurations
inspired by results from binary black holes. First, we show that choosing a
modified Kerr-Schild conformal metric instead of a flat conformal metric allows
for the construction of quasi-equilibrium binaries with a spinning black hole.
Second, we construct binaries in low-eccentricity orbits, which are a better
approximation to astrophysical binaries than quasi-equilibrium systems.Comment: 19 pages, 11 figures, Modified to match final PRD versio
The Earliest Phases of Galaxy Evolution
In this paper we study the very early phases of the evolution of our Galaxy
by means of a chemical evolution model which reproduces most of the
observational constraints in the solar vicinity and in the disk. We have
restricted our analysis to the solar neighborhood and present the predicted
abundances of several elements (C, N, O, Mg, Si, S, Ca, Fe) over an extended
range of metallicities to compared to previous
models. We adopted the most recent yield calculations for massive stars taken
from different authors (Woosley & Weaver 1995 and Thielemann et al. 1996) and
compared the results with a very large sample of data, one of the largest ever
used to this purpose. These data have been analysed with a new and powerful
statistical method which allows us to quantify the observational spread in
measured elemental abundances and obtain a more meaningful comparison with the
predictions from our chemical evolution model. Our analysis shows that the
``plateau'' observed for the [/Fe] ratios at low metallicities () is not perfectly constant but it shows a slope, especially for
oxygen. This slope is very well reproduced by our model with both sets of
yields. This is not surprising since realistic chemical evolution models,
taking into account in detail stellar lifetimes, never predicted a completely
flat plateau. This is due either to the fact that massive stars of different
mass produce a slightly different O/Fe ratio or to the often forgotten fact
that supernovae of type Ia, originating from white dwarfs, start appearing
already at a galactic age of 30 million years and reach their maximum at 1 Gyr.Comment: 32 pages, 9 figures, to be published in Ap
An ab initio study of the C3(+) cation using multireference methods
The energy difference between the linear 2 sigma(sup +, sub u) and cyclic 2B(sub 2) structures of C3(+) has been investigated using large (5s3p2d1f) basis sets and multireference electron correlation treatments, including complete active space self consistent fields (CASSCF), multireference configuration interaction (MRCI), and averaged coupled-pair functional (ACPF) methods, as well as the single-reference quadratic configuration interaction (QCISD(T)) method. Our best estimate, including a correction for basis set incompleteness, is that the linear form lies above the cyclic from by 5.2(+1.5 to -1.0) kcal/mol. The 2 sigma(sup +, sub u) state is probably not a transition state, but a local minimum. Reliable computation of the cyclic/linear energy difference in C3(+) is extremely demanding of the electron correlation treatment used: of the single-reference methods previously considered, CCSD(T) and QCISD(T) perform best. The MRCI + Q(0.01)/(4s2p1d) energy separation of 1.68 kcal/mol should provide a comparison standard for other electron correlation methods applied to this system
The Canada-UK Deep Sub-Millimeter Survey II: First identifications, redshifts and implications for galaxy evolution
Identifications are sought for 12 sub-mm sources detected by Eales et al
(1998). Six are securely identified, two have probable identifications and four
remain unidentified with I_AB > 25. Spectroscopic and estimated photometric
redshifts indicate that four of the sources have z < 1, and four have 1 < z <
3, with the remaining four empty field sources probably lying at z > 3. The
spectral energy distributions of the identifications are consistent with those
of high extinction starbursts such as Arp 220. The far-IR luminosities of the
sources at z > 0.5 are of order 3 x 10^12 h_50^-2 L_sun, i.e. slightly larger
than that of Arp 220. Based on this small sample, the cumulative bolometric
luminosity function shows strong evolution to z ~ 1, but weaker or possibly
even negative evolution beyond. The redshift dependence of the far-IR
luminosity density does not appear, at this early stage, to be inconsistent
with that seen in the ultraviolet luminosity density. Assuming that the energy
source in the far-IR is massive stars, the total luminous output from
star-formation in the Universe is probably dominated by the far-IR emission.
The detected systems have individual star-formation rates (exceeding 300
h_50^-2 M_O yr^-1) that are much higher than seen in the ultraviolet selected
samples, and which are sufficient to form substantial stellar populations on
dynamical timescales of 10^8 yr. The association with merger-like morphologies
and the obvious presence of dust makes it attractive to identify these systems
as forming the metal-rich spheroid population, in which case we would infer
that much of this activity has occurred relatively recently, at z ~ 2.Comment: 17 pages text + 14 figures. Accepted for publication in the
Astrophysical Journal. Gzipped tar file contains one text.ps file for text
and tables, one Fig2.jpg file for Fig 2, and 13 Fig*.ps files for the
remaining figure
Sulfur reduction in sediments of marine and evaporite environments
Transformations of sulfur in sediments of ponds ranging in salinities from that of normal seawater to those of brines saturated with sodium chloride were examined. The chemistry of the sediment and pore waters were focused on with emphasis on the fate of sulfate reduction. The effects of increasing salinity on both forms of sulfur and microbial activity were determined. A unique set of chemical profiles and sulfate-reducing activity was found for the sediments of each of the sites examined. The quantity of organic matter in the salt pond sediments was significantly greater than that occurring in the adjacent intertidal site. The total quantitative and qualitative distribution of volatile fatty acids was also greater in the salt ponds. Volatile fatty acids increased with salinity
Giraffe translocation population viability analysis
Most populations of giraffes have declined in recent decades, leading to the recent IUCN decision to upgrade the species to Vulnerable status, and some subspecies to Endangered. Translocations have been used as a conservation tool to re-introduce giraffes to previously occupied areas or establish new populations, but guidelines for founding populations are lacking. To provide general guidelines for translocation projects regarding feasibility, we simulated various scenarios of translocated giraffe populations to identify viable age and sex distributions of founding populations using population viability analysis (PVA) implemented in Vortex software. We explored the parameter space for demography and the genetic load, examining how variation in founding numbers and sex ratios affected 100 yr probability of population extinction and genetic diversity. We found that even very small numbers of founders (N ≤ 10 females) can appear to be successful in the first decades due to transient positive population growth, but with moderate population growth rate and moderate genetic load, long-term population viability (probability of extinction 95% genetic diversity of the source population in an isolated population, 50 females and 5 males are recommended to compose the founding population. Sensitivity analyses revealed first-year survival and reproductive rate were the simulation parameters with the greatest proportional influence on probability of extinction and genetic diversity. These simulations highlight important considerations for translocation success and data gaps including true genetic load in wild giraffe populations
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