8,699 research outputs found
Vacuum Cerenkov Radiation in Lorentz-Violating Theories Without CPT Violation
In theories with broken Lorentz symmetry, Cerenkov radiation may be possible
even in vacuum. We analyze the Cerenkov emissions that are associated with the
least constrained Lorentz-violating modifications of the photon sector,
calculating the threshold energy, the frequency spectrum, and the shape of the
Mach cone. In order to obtain sensible results for the total power emitted, we
must make use of information contained within the theory which indicates at
what scale new physics must enter.Comment: 9 page
Cerenkov Radiation in a Lorentz-Violating and Birefringent Vacuum
We calculate the emission spectrum for vacuum Cerenkov radiation in
Lorentz-violating extensions of electrodynamics. We develop an approach that
works equally well if the presence or the absence of birefringence. In addition
to confirming earlier work, we present the first calculation relevant to
Cerenkov radiation in the presence of a birefringent photon k_F term,
calculating the lower-energy part of the spectrum for that case.Comment: 17 pages, version to appear in Phys. Rev.
THE IMPACT OF HEALTH, ENVIRONMENTAL AND SOCIAL ATTRIBUTES OF SALMON CHOICE IN THE UNITED STATES
In recent years, U.S. consumers have increasingly sought information about the health implications of their food purchases, as well as the environmental and social impact of the food production process. While this growing consumer demand has helped facilitate the development of several seafood certification programs, no accessible public or private data shows that U.S. shoppers are willing to pay a premium for certified seafood. To estimate whether a price premium exists for current and forthcoming certifications for wild and farmed salmon producers, and to better understand U.S. consumers’ preferences for salmon, we surveyed a representative sample of 955 shoppers from the United States. We then conducted a conjoint analysis on their willingness to pay for different methods of production (wild or farmed), countries or regions of origin, the Marine Stewardship Council’s wild seafood ‘ecolabel’, and hypothetical certifications assuring that the salmon product is associated with fewer health risks, environmental impacts, or negative social issues. Of the factors which affect consumers’ salmon purchasing decisions, the combination of fresh salmon’s method of production and its region of origin is generally a stronger determinant of U.S. salmon shopper’s purchasing decisions than the salmon’s certifications. Consumers strongly favor wild salmon to farmed salmon, prefer salmon from the United States to salmon from other countries, are willing to pay the largest premiums for environmental certifications, and state they are willing to pay the lowest premium for the health and safety certification. Results show that 1) fresh salmon producers and retailers have financial incentives to display social and environmental labels at seafood counters in markets, 2) a price premium for a health and safety certification of farmed salmon would be limited, since salmon consumers are more responsive to negative than positive information related to health issues associated with the salmon that they purchase, and 3) certifying agencies, and all retailers have financial incentives to inform consumers about the benefits and risks of salmon production and consumption, because informed consumers are willing to pay more for certified fresh salmon as well as most types of uncertified fresh salmon.Agricultural and Food Policy, Consumer/Household Economics, Demand and Price Analysis, Food Consumption/Nutrition/Food Safety, Food Security and Poverty, Health Economics and Policy,
Bounds on Spin-Dependent Lorentz Violation From Inverse Compton Observations
Some of the best bounds on possible Lorentz violation in the electron sector
come from observations of high-energy astrophysical phenomena. Using
measurements of TeV inverse Compton radiation from a number of sources, we
place the first bounds--at the 10^(-15) level--on seven of the electron d
coefficients.Comment: 10 page
Estimating the Indirect Effect of Sports Books on Other In-House Gaming Volumes
Using data from a repeater market hotel in Las Vegas, Nevada, the relationship between sports book and slot machine revenues is examined. Daily sports book write and daily slot handle are compared over a 250 day period. Though many industry leaders theorize that sports book gamblers also wager in slot banks, the results of this Autoregressive Integrated Moving Average (ARIMA) analysis fail to demonstrate a statistically significant relationship between sports book write and slot coin-in at the 0.05 alpha cutoff. This study advances literature currently available by establishing the lack of such a relationship and disputing the generally accepted assumption that sports books produce a substantial indirect contribution to slot revenues. While the sports book does generate a fairly constant direct profit for the casino, the absolute value of that profit is minimal and the results of the study show there is no indirect profit contribution from sports books to slot machines. Given these results, casino management may want to consider that a sports book is not an optimal use of casino floor space
Screening for familial hypercholesterolaemia in primary care: Time for general practice to play its part
Fifty per cent of first-degree relatives of index cases with familial hypercholesterolemia (FH) inherit the disorder. Despite cascade screening being the most cost-effective method for detecting new cases, only a minority of individuals with FH are currently identified. Primary care is a key target area to increase identification of new index cases and initiate cascade screening, thereby finding close relatives of all probands. Increasing public and health professional awareness about FH is essential.
In the United Kingdom and in Australia, most of the population are reviewed by a General Practitioner (GP) at least once over a three-year period, offering opportunities to check for FH as part of routine clinical consultations. Such opportunistic approaches can be supplemented by systematically searching electronic health records with information technology tools that identify high risk patients. GPs can help investigate and implement results of this data retrieval.
Current evidence suggests that early detection of FH and cascade testing meet most of the criteria for a worthwhile screening program. Among heterozygous patients the long latent period before the expected onset of coronary artery disease provides an opportunity for initiating effective drug and lifestyle changes. The greatest challenge for primary care is to implement an efficacious model of care that incorporates sustainable identification and management pathways
Laboratory Bounds on Electron Lorentz Violation
Violations of Lorentz boost symmetry in the electron and photon sectors can
be constrained by studying several different high-energy phenomenon. Although
they may not lead to the strongest bounds numerically, measurements made in
terrestrial laboratories produce the most reliable results. Laboratory bounds
can be based on observations of synchrotron radiation, as well as the observed
absences of vacuum Cerenkov radiation. Using measurements of synchrotron energy
losses at LEP and the survival of TeV photons, we place new bounds on the three
electron Lorentz violation coefficients c_(TJ), at the 3 x 10^(-13) to 6 x
10^(-15) levels.Comment: 18 page
Synchrotron and Inverse Compton Constraints on Lorentz Violations for Electrons
We present a method for constraining Lorentz violation in the electron
sector, based on observations of the photons emitted by high-energy
astrophysical sources. The most important Lorentz-violating operators at the
relevant energies are parameterized by a tensor c^{nu mu) with nine independent
components. If c is nonvanishing, then there may be either a maximum electron
velocity less than the speed of light or a maximum energy for subluminal
electrons; both these quantities will generally depend on the direction of an
electron's motion. From synchrotron radiation, we may infer a lower bound on
the maximum velocity, and from inverse Compton emission, a lower bound on the
maximum subluminal energy. With observational data for both these types of
emission from multiple celestial sources, we may then place bounds on all nine
of the coefficients that make up c. The most stringent bound, on a certain
combination of the coefficients, is at the 6 x 10^(-20) level, and bounds on
the coefficients individually range from the 7 x 10^(-15) level to the 2 x
10^(-17) level. For most of the coefficients, these are the most precise bounds
available, and with newly available data, we can already improve over previous
bounds obtained by the same methods.Comment: 28 page
The search for novel analgesics: re-examining spinal cord circuits with new tools
In this perspective, we propose the absence of detailed information regarding spinal cord
circuits that process sensory information remains a major barrier to advancing analgesia.
We highlight recent advances showing that functionally discrete populations of neurons in
the spinal cord dorsal horn play distinct roles in processing sensory information. We then
discuss new molecular, electrophysiological, and optogenetic techniques that can be
employed to understand how dorsal horn circuits process tactile and nociceptive
information. We believe this information can drive the development of entirely new classes
of pharmacotherapies that target key elements in spinal circuits to selectively modify
sensory function and blunt pain
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