10,694 research outputs found
Climate Variability and Health: Sweden 1751-2004
Several studies have examined the link between climate and health, mainly focusing on the short term impacts of extreme temperatures. This paper analyzes instead the long term relation between climate variability and health using Swedish temperature and mortality data for the period 1751-2004 using different time scales. We find that periods with higher temperature are associated with lower mortality. The results indicate that long term climate variations in annual mean temperatures and not short term variations explain the connection between temperature and mortality. Considering annual extreme temperatures, we find that extreme low winter temperatures are correlated with higher short term mortality. We identify the impact of the 11-year solar cycle on crop yields as a possible explanation for our findings. The results have besides their economic-historical merits implications for modern day policy for developing countries, especially since the correlation with solar activity implies predictability.Mortality; Wavelet; Climate
One-Nucleon Effective Generators of the Poincare Group derived from a Field Theory: Mass Renormalization
We start from a Lagrangian describing scalar "nucleons" and mesons which
interact through a simple vertex. Okubo's method of unitary transformation is
used to describe a single nucleon dressed by its meson cloud. We find an
expression for the physical mass of the nucleon being correct up to second
order in the coupling constant. It is then verified that this result is the
same as the corresponding expression found by Feynman techniques. Finally we
also express the three boost operators in terms of the physical nucleon mass.
Doing so we find expressions for all the ten generators of Poincar\'e
transformations for the system of one single dressed nucleon.Comment: 19 pages, no figure
Driven colloidal suspensions in confinement and density functional theory: Microstructure and wall-slip
We theoretically investigate general properties of driven (sheared) colloidal
suspensions in confinement, based on methods of classical density functional
theory. In the absence of an exact closed (Smoluchowski-) equation for the
one-particle density under shear, we formulate a set of general conditions for
approximations, and show that a simple closure fulfills them. The exact
microscopic stress tensor is identified. Exemplifying the situation near a wall
(oriented parallel to the direction of shear), we note that the microscopic
shear stress is not necessarily homogeneous. Formulating a second equation
additional to the Smoluchowski equation, we achieve a homogeneous shear stress,
and thereby compute the local flow velocity near the wall. This finally leads
to a slip length of the complex fluid at the wall.Comment: 11 pages, 8 figure
Theory of rheology in confinement
The viscosity of fluids is generally understood in terms of kinetic
mechanisms, i.e., particle collisions, or thermodynamic ones as imposed through
structural distortions upon e.g. applying shear. Often the former is less
relevant, and (damped) Brownian particles are considered good fluid model
systems. We formulate a general theoretical approach for rheology in
confinement, based on the many particle diffusion equation, evaluated via
classical density functional theory. We discuss the viscosity for the situation
of two parallel walls in relative motion as a function of wall-to-wall
distance.Comment: 5 pages, 3 figure
Episode of unusual high solar ultraviolet radiation over central Europe due to dynamical reduced total ozone in May 2005
In late May 2005 unusual high levels of solar ultraviolet radiation were observed over central Europe. In Northern Germany the measured irradiance of erythemally effective radiation exceeded the climatological mean by more than about 20%. An extreme low ozone event for the season coincided with high solar elevation angles and high pressure induced clear sky conditions leading to the highest value of erythemal UV-radiation ever observed over this location in May since 1994. This hereafter called "ozone mini-hole" was caused by an elevation of tropopause height accompanied with a poleward advection of ozone-poor air from the tropics. The resultant increase in UV-radiation is of particular significance for human health. Dynamically induced low ozone episodes that happen in late spring can considerably enhance the solar UV-radiation in mid latitudes and therefore contribute to the UV-burden of people living in these regions
Good Times Are Drinking Times: Empirical Evidence on Business Cycles an Alcohol Sales in Sweden 1861-2000
This paper studies the relationship between the business cycle and alcohol sales in Sweden using a data set for the years 1861-2000. Using wavelet based band-pass filtering it is found that there is a pro-cyclical relationship, i.e. alcohol sales increases in short-term economic upturns. Using moving window techniques we see that the pro-cyclical relationship holds over the entire time period. We also find that alcohol sales are a long-memory process with non-stationary behavior, i.e. a shock in alcohol sales has persistent effectsBusinesscycles:Alcohol:Sweden
The Impact of Real Options on Willingness to Pay for Investments in Road Safety
Abstract: Public investments are dynamic in nature, and decision making must account for the uncertainty, irreversibility and potential for future learning. In this paper we adapt the theory for investment under uncertainty for a public referendum setting and perform the first empirical test to show that estimates of the value of safety (VSL) from stated preference surveys are highly dependent on the inclusion of the option value. Our results indicate an option value of a major economic magnitude. This implies that previously reported VSL estimates are exaggerated.Value of a Statistical Life; Real Options; Contingent Valuation; Road Safety
The sejugal furrow in camel spiders and acariform mites
Camel spiders (Arachnida: Solifugae) are one of the arachnid groups characterised by a prosomal dorsal shield composed of three distinct elements: the pro-, meso- and metapeltidium. These are associated respectively with prosomal appendages one to four, five, and six. What is less well known, although noted in the historical literature, is that the coxae of the 4th and 5th prosomal segments (i.e. walking legs 2 and 3) of camel spiders are also separated ventrally by a distinct membranous region, which is absent between the coxae of the other legs. We suggest that this essentially ventral division of the prosoma specifically between coxae 2 and 3 is homologous with the so-called sejugal furrow (the sejugal interval sensu van der Hammen). This division constitutes a fundamental part of the body plan in acariform mites (Arachnida: Acariformes). If homologous, this sejugal furrow could represent a further potential synapomorphy for (Solifugae + Acariformes); a relationship with increasing morphological and molecular support. Alternatively, outgroup comparison with sea spiders (Pycnogonida) and certain early Palaeozoic fossils could imply that the sejugal furrow defines an older tagma, derived from a more basal grade of organisation. In this scenario the (still) divided prosoma of acariform mites and camel spiders would be plesiomorphic. This interpretation challenges the textbook arachnid character of a peltidium (or ‘carapace’) covering an undivided prosoma
Linear response relations in fluctuational electrodynamics
Near field radiative heat transfer and dynamic Casimir forces are just two
instances of topics of technological and fundamental interest studied via the
formalism of fluctuational electrodynamics. From the perspective of experiment
and simulations, it is hard to precisely control and probe such non-equilibrium
situations. Fluctuations in equilibrium are easier to measure, and can
typically be related to non-equilibrium response functions by Green-Kubo
relations. We consider a collection of arbitrary objects in vacuum, perturbed
by changing the temperature or velocity of one object. Developing a method for
computation of higher order correlation functions in fluctuational
electrodynamics, we explicitly compare linear response and equilibrium
fluctuations. We obtain a Green-Kubo relation for the radiative heat transfer,
as well as a closed formula for the vacuum friction in arbitrary geometries in
the framework of scattering theory. We comment on the signature of the
radiative heat conductivity in equilibrium fluctuations.Comment: Main article: 5 pages, 2 figures; Supplemental Material: 2 page
Neutron matter from chiral effective field theory interactions
The neutron-matter equation of state constrains the properties of many
physical systems over a wide density range and can be studied systematically
using chiral effective field theory (EFT). In chiral EFT, all many-body forces
among neutrons are predicted to next-to-next-to-next-to-leading order (N3LO).
We present details and additional results of the first complete N3LO
calculation of the neutron-matter energy, which includes the subleading
three-nucleon as well as the leading four-nucleon forces, and provides
theoretical uncertainties. In addition, we discuss the impact of our results
for astrophysics: for the supernova equation of state, the symmetry energy and
its density derivative, and for the structure of neutron stars. Finally, we
give a first estimate for the size of the N3LO many-body contributions to the
energy of symmetric nuclear matter, which shows that their inclusion will be
important in nuclear structure calculations.Comment: published version; 21 pages, 11 figures, 5 table
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