38,910 research outputs found
Livestock products in the Third World: past trends and projections to 1990 and 2000
Meat industry and trade Developing countries Statistics., Dairy products industry Developing countries Statistics., Meat industry and trade Developing countries Forecasting Statistical methods., Dairy products industry Developing countries Forecasting Statistical methods.,
Numerical solution of a non-linear conservation law applicable to the interior dynamics of partially molten planets
The energy balance of a partially molten rocky planet can be expressed as a
non-linear diffusion equation using mixing length theory to quantify heat
transport by both convection and mixing of the melt and solid phases. In this
formulation the effective or eddy diffusivity depends on the entropy gradient,
, as well as entropy. First we present a simplified
model with semi-analytical solutions, highlighting the large dynamic range of
, around 12 orders of magnitude, for physically-relevant
parameters. It also elucidates the thermal structure of a magma ocean during
the earliest stage of crystal formation. This motivates the development of a
simple, stable numerical scheme able to capture the large dynamic range of
and provide a flexible and robust method for
time-integrating the energy equation.
We then consider a full model including energy fluxes associated with
convection, mixing, gravitational separation, and conduction that all depend on
the thermophysical properties of the melt and solid phases. This model is
discretised and evolved by applying the finite volume method (FVM), allowing
for extended precision calculations and using as the
solution variable. The FVM is well-suited to this problem since it is naturally
energy conserving, flexible, and intuitive to incorporate arbitrary non-linear
fluxes that rely on lookup data. Special attention is given to the numerically
challenging scenario in which crystals first form in the centre of a magma
ocean.
Our computational framework is immediately applicable to modelling high melt
fraction phenomena in Earth and planetary science research. Furthermore, it
provides a template for solving similar non-linear diffusion equations arising
in other disciplines, particularly for non-linear functional forms of the
diffusion coefficient
Letter to Readers, Table of Contents, and Members of the National Seminar on Jesuit Higher Education
Entanglement witnesses and a loophole problem
We consider a possible detector-efficiency loophole in experiments that
detect entanglement via the local measurement of witness operators. Here, only
local properties of the detectors are known. We derive a general threshold for
the detector efficiencies which guarantees that a negative expectation value of
a witness is due to entanglement, rather than to erroneous detectors. This
threshold depends on the local decomposition of the witness and its measured
expectation value. For two-qubit witnesses we find the local operator
decomposition that is optimal with respect to closing the loophole.Comment: 5 pages, 2 figures, published versio
Viscous fingering in miscible, immiscible and reactive fluids
With the Lattice Boltzmann method (using the BGK approximation) we
investigate the dynamics of Hele-Shaw flow under conditions corresponding to
various experimental systems. We discuss the onset of the instability
(dispersion relation), the static properties (characterization of the
interface) and the dynamic properties (growth of the mixing zone) of simulated
Hele-Shaw systems. We examine the role of reactive processes (between the two
fluids) and we show that they have a sharpening effect on the interface similar
to the effect of surface tension.Comment: 6 pages with 2 figure, to be published in J.Mod.Phys
A Deep Multicolor Survey I. Imaging Observations and Catalog of Stellar Objects
We have used the KPNO 4-meter Mayall telescope to image 0.83 square degrees
of sky in six fields at high galactic latitude in six filters spanning
3000-10000\AA\ to magnitude limits ranging from 22.1 to 23.8. We have assembled
a catalog of 21,375 stellar objects detected in the fields for use primarily in
conducting a multicolor search for quasars. This paper describes the data
reduction techniques used on the CCD data, the methods used to construct the
stellar object catalog, and the simulations performed to understand its
completeness and contamination.Comment: To Appear in ApJ Supplement, 1996. 168k uuencoded gunzipped tarred
tex file (requires aas2pp4.sty and tighten.sty) and 4 PostScript figures.
Also available at http://astro.as.arizona.edu/~pathall/astro.html#preprint
Molecular Genetic Typing of Staphylococcus aureus from Cows, Goats, Sheep, Rabbits and Chickens
End of project reportsS. aureus can also cause a number of infections in animals such as tick-associated pyaemia in lambs, staphylococcosis in rabbits, septicaemia, abscesses and chondronecrosis in chickens and pneumonia and osteomyelitis complex in turkeys. S. aureus is the most frequent cause of bovine mastitis, a disease that is of economic importance worldwide (Beck et al., 1992). Typically staphylococcal mastitis is chronic in nature, with subclinical mastitis being the most common form
Privacy Attitudes among Early Adopters of Emerging Health Technologies.
IntroductionAdvances in health technology such as genome sequencing and wearable sensors now allow for the collection of highly granular personal health data from individuals. It is unclear how people think about privacy in the context of these emerging health technologies. An open question is whether early adopters of these advances conceptualize privacy in different ways than non-early adopters.PurposeThis study sought to understand privacy attitudes of early adopters of emerging health technologies.MethodsTranscripts from in-depth, semi-structured interviews with early adopters of genome sequencing and health devices and apps were analyzed with a focus on participant attitudes and perceptions of privacy. Themes were extracted using inductive content analysis.ResultsAlthough interviewees were willing to share personal data to support scientific advancements, they still expressed concerns, as well as uncertainty about who has access to their data, and for what purpose. In short, they were not dismissive of privacy risks. Key privacy-related findings are organized into four themes as follows: first, personal data privacy; second, control over personal information; third, concerns about discrimination; and fourth, contributing personal data to science.ConclusionEarly adopters of emerging health technologies appear to have more complex and nuanced conceptions of privacy than might be expected based on their adoption of personal health technologies and participation in open science. Early adopters also voiced uncertainty about the privacy implications of their decisions to use new technologies and share their data for research. Though not representative of the general public, studies of early adopters can provide important insights into evolving attitudes toward privacy in the context of emerging health technologies and personal health data research
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