16,385 research outputs found
Altruism, Fertility, and the Value of Children: Health Policy Evaluation and Intergenerational Welfare
This paper accounts for the value of children and future generations in the evaluation of health policies. This is achieved through the incorporation of altruism and fertility in "value of life" type of framework. We are able to express adults' willingness to pay for changes in child mortality and also to incorporate the welfare of future generations in the evaluation of current policies. Our model clarifies a series of puzzles from the literature on the "value of life" and on intergenerational welfare comparisons. We show that, by incorporating altruism and fertility into the analysis, the estimated welfare gain from recent reductions in mortality in the U.S. easily doubles.
SWINE WASTE PHYTOREMEDIATION USING DUCKWEED (Landoltia punctata, Les & Crawford) IN A FULL SCALE PLANT
Banner Apresentado em Congresso: 11th International Conference, Heraklion, Crete, Greece PhytotechnologiesThe large amount of nitrogen and phosphorous compounds found in pig manure has caused ecological imbalances, with eutrophication of major river basins in the producing regions. Therefore, the aquatic macrophytes group named duckweeds (Araceae; Lemnoideae) have been successfully used for phytoextraction and rhizodegradation of nutrient and heavy metals from swine waste, generating further a biomass with high protein content. The present study evaluated the phytoremediation of nitrogen and phosphorus from swine waste using the duckweed Landoltia punctata and also their protein biomass production as by-product
Galactic halo stellar structures in the Triangulum-Andromeda region
This letter reports on the Galactic stellar structures that appear in the
foreground of our Canada-France-Hawaii-Telecopse/MegaCam survey of the halo of
the Andromeda galaxy. We recover the main sequence and main sequence turn-off
of the Triangulum-Andromeda structure recently found by Majewski and
collaborators at a heliocentric distance of ~20 kpc. The survey also reveals
another less populated main sequence at fainter magnitudes that could
correspond to a more distant stellar structure at ~28 kpc. Both structures are
smoothly distributed over the ~76 sq. deg. covered by the survey although the
closer one shows an increase in density by a factor of ~2 towards the
North-West. The discovery of a stellar structure behind the
Triangulum-Andromeda structure that itself appears behind the low-latitude
stream that surrounds the Galactic disk gives further evidence that the inner
halo of the Milky Way is of a spatially clumpy nature.Comment: accepted for publication in ApJL, 4 pages, 4 figures. Significant
changes including a larger dataset and a more thorough discussio
Numerical modeling of strain rate hardening effects on viscoplastic behavior of metallic materials
The main goal of the present work is to provide a finite strain elasticviscoplastic framework to numerically account for strain, strain rate hardening, and viscous effects in cold deformation of metallic materials. The aim is to provide a simple and robust numerical framework capable of modeling the main macroscopic behavior associated with high strain rate plastic deformation of metals. In order to account for strain rate hardening effects at finite strains, the hardening rule involves a rate dependent saturation hardening, and it accounts for linear hardening prevailing at latter deformation stages. The numerical formulation, finite element implementation, and constitutive modeling capabilities are assessed by means of decremental strain rate testing and constant strain rate loading followed by stress relaxation. The numerical results have demonstrated the overall framework can be an efficient numerical tool for simulation of plastic deformation processes where strain rate history effects have to be accounted for
Some numerical verification examples for plane stress elasto-viscoplasticity
This paper presents analytical, semi-analytical and numerical reference examples which can be employed for code verification of elasto-viscoplastic models under plane stress conditions. Mainly because of the overstress function the algorithms traditionally employed in elasto-plastic implementations must be rewritten to correctly impose the plane stress state along with the viscoplastic flow. The viscoplastic formulation presented here considers the strain-rate hardening effects by means of a hardening law that are assumed to have terms depending on the strain rate, which removed can represent a Voce type hardening. The proposed verification tests were employed for the numerical verification of an in-house implementation of the so-called stress-projected procedure inside the finite element method context. Although the focus of this paper is on the stressprojected algorithms the examples presented here can be employed for the verification of other algorithms intended to impose the plane stress state in viscoplasticit
Using full-scale duckweed ponds as the finish stage for swine waste treatment with a focus on organic matter degradation
Artigo Publicado em: IWA - Water Science & TechnologyThe rapid increase in the number of swine has caused pronounced environmental impacts worldwide, especially on water resources. As an aggregate, smallholdings have an important role in South American pork production, contributing to the net diffusion of pollution. Thus, duckweed ponds have been successfully used for swine waste polishing, mainly for nutrient removal. Few studies have been carried out to assess organic matter degradation in duckweed ponds. Hence, the present study evaluated the efficiency of two full-scale duckweed ponds for organic matter reduction of swine waste on small pig farms. Duckweed ponds, in series, received the effluent after an anaerobic biodigester and storage pond, with a flow rate of 1 m3 day 1. After 1 year of monitoring, an improvement in effluent quality was observed, with a reduction in biochemical oxygen demand (BOD) and total chemical oxygen demand (tCOD), respectively, of 94.8 and 96.7%, operating at a loading rate of approximately 27 kgBOD ha 1 day 1 and 131 kgCOD ha 1 day 1. Algae inhibition due to duckweed coverage was strongly observed in the pond effluent, where chlorophyll a and turbidity remained below 25 μg L 1 and 10 NTU. Using the study conditions described herein, duckweed ponds were shown to be a suitable technology for swine waste treatment, contributing to the environmental sustainability of rural areas
A Detection of Gas Associated with the M 31 Stellar Stream
Detailed studies of stellar populations in the halos of the Milky Way and the
Andromeda (M 31) galaxies have shown increasing numbers of tidal streams and
dwarf galaxies, attesting to a complicated and on-going process of hierarchical
structure formation. The most prominent feature in the halo of M 31 is the
Giant Stellar Stream, a structure ~4.5 degrees in extent along the sky, which
is close to, but not coincident with the galaxy's minor axis. The stars that
make up this stream are kinematically and chemically distinct from the other
stars in the halo. Here, we present HST/COS high-resolution ultraviolet
absorption spectra of three Active Galactic Nuclei sight lines which probe the
M 31 halo, including one that samples gas in the main southwestern portion of
the Giant Stream. We see two clear absorption components in many metal species
at velocities typical of the M 31 halo and a third, blue-shifted component
which arises in the stream. Photoionization modeling of the column density
ratios in the different components shows gas in an ionization state typical of
that seen in other galaxy halo environments and suggests solar to slightly
super-solar metallicity, consistent with previous findings from stellar
spectroscopy.Comment: 10 pages, 5 figures, accepted for publication in the Astrophysical
Journa
The role of the disorder range and electronic energy in the graphene nanoribbons perfect transmission
Numerical calculations based on the recursive Green's functions method in the
tight-binding approximation are performed to calculate the dimensionless
conductance in disordered graphene nanoribbons with Gaussian scatterers.
The influence of the transition from short- to long-ranged disorder on is
studied as well as its effects on the formation of a perfectly conducting
channel. We also investigate the dependence of electronic energy on the
perfectly conducting channel. We propose and calculate a backscattering
estimative in order to establish the connection between the perfectly
conducting channel (with ) and the amount of intervalley scattering.Comment: 7 pages, 9 figures. To be published on Phys. Rev.
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