10,226 research outputs found
Electroweak Constraints from Atomic Parity Violation and Neutrino Scattering
Precision electroweak physics can provide fertile ground for uncovering new
physics beyond the Standard Model (SM). One area in which new physics can
appear is in so-called "oblique corrections", i.e., next-to-leading order
expansions of bosonic propagators corresponding to vacuum polarization. One may
parametrize their effects in terms of quantities and that discriminate
between conservation and non-conservation of isospin. This provides a means of
comparing the relative contributions of precision electroweak experiments to
constraints on new physics. Given the prevalence of strongly -sensitive
experiments, there is an acute need for further constraints on , such as
provided by atomic parity-violating experiments on heavy atoms. We evaluate
constraints on arising from recently improved calculations in the Cs atom.
We show that the top quark mass provides stringent constraints on
within the context of the Standard Model. We also consider the potential
contributions of next-generation neutrino scattering experiments to improved
constraints.Comment: 10 pages, 4 figures, final corrected version to be published in
Physical Review
Space missions to comets
The broad impact of a cometary mission is assessed with particular emphasis on scientific interest in a fly-by mission to Halley's comet and a rendezvous with Tempel 2. Scientific results, speculations, and future plans are discussed
Network-constrained models of liberalized electricity markets: the devil is in the details
Numerical models for electricity markets are frequently used to inform and support decisions. How robust are the results? Three research groups used the same, realistic data set for generators, demand and transmission network as input for their numerical models. The results coincide when predicting competitive market results. In the strategic case in which large generators can exercise market power, the predicted prices differed significantly. The results are highly sensitive to assumptions about market design, timing of the market and assumptions about constraints on the rationality of generators. Given the same assumptions the results coincide. We provide a checklist for users to understand the implications of different modelling assumptions.Market power, Electricity, Networks, Numeric models, Model comparison
Gravitational wave detection using pulsars: status of the Parkes Pulsar Timing Array project
The first direct detection of gravitational waves may be made through
observations of pulsars. The principal aim of pulsar timing array projects
being carried out worldwide is to detect ultra-low frequency gravitational
waves (f ~ 10^-9 to 10^-8 Hz). Such waves are expected to be caused by
coalescing supermassive binary black holes in the cores of merged galaxies. It
is also possible that a detectable signal could have been produced in the
inflationary era or by cosmic strings. In this paper we review the current
status of the Parkes Pulsar Timing Array project (the only such project in the
Southern hemisphere) and compare the pulsar timing technique with other forms
of gravitational-wave detection such as ground- and space-based interferometer
systems.Comment: Accepted for publication in PAS
Techniques development for whale migration tracking
Effort leading to the completion of development and fabrication of expansible whale harnesses and whale-carried instrument pods is described, along with details of the gear. Early preparative effort for a January-February 1974 field expedition is reported
Magnetically-controlled velocity selection in a cold atom sample using stimulated Raman transitions
We observe velocity-selective two-photon resonances in a cold atom cloud in
the presence of a magnetic field. We use these resonances to demonstrate a
simple magnetometer with sub-mG resolution. The technique is particularly
useful for zeroing the magnetic field and does not require any additional laser
frequencies than are already used for standard magneto-optical traps. We verify
the effects using Faraday rotation spectroscopy.Comment: 5 pages, 6 figure
Long term changes in health-related quality of life for people with heart failure:the ECHOES study
Aims: Heart failure (HF) impairs all aspects of health-related quality of life (HRQoL), but little is known about the effect of developing HF on HRQoL over time. We aimed to report changes in HRQoL over a 13-year period. Methods and results: HRQoL was measured in the Echocardiographic Heart of England Screening (ECHOES) study and the ECHOES-X follow-up study (N = 1618) using the SF-36 questionnaire (Version 1). Mixed modelling compared changes in HRQoL across diagnostic groups, adjusting for potential predictors and design variables. Patients who had developed HF with reduced ejection fraction (HFrEF) or HF with preserved ejection fraction (HFpEF) at rescreening had significantly greater reduction in physical functioning (PF) and role physical (RP) scores compared with those without HF; adjusted mean difference in PF: HFrEF −16.1, [95% confidence interval (CI) −22.2 to −10.1]; HFpEF −14.6, (95% CI −21.2 to −8.1); in RP: HFrEF −20.7, (95% CI −31.8 to −9.7); HFpEF −19.3, (95% CI −31.0 to −7.6). Changes in HRQoL of those with a HF diagnosis at baseline and rescreen, with exception of role emotion, were similar to those without HF but started from a much lower baseline score. Conclusions: People with a new diagnosis of HF at rescreening had a significant reduction in HRQoL. Conversely, for those with HF detected on initial screening, little change was observed in HRQoL scores on rescreening. Further research is required to understand the development of HF over time and to test interventions designed to prevent decline in HRQoL, potentially through earlier diagnosis and treatment optimization.</p
The Total Economic Costs Of Finance Faculty Replacement
The purpose of this study is to estimate the total economic costs associated with filling a vacated finance faculty line. These economic costs include both explicit and opportunity costs associated with the production process. Hiring costs include explicit costs such as advertising the position and implicit costs such as the opportunity costs of faculty time spent in various search committee activities. In addition, the recent market for finance professors has included a significant mark-to-market salary component associated with replacing departed faculty with new hires. This paper utilizes survey data from recent finance faculty vacancies at AACSB International accredited schools to estimate the total hiring cost equation
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Provision of ecosystem services by hedges in urban domestic gardens: focus on rainfall mitigation
In the UK urban context, domestic gardens are an important resource, taking up to 25% of an urban area, with hedges being their popular and widespread features. Garden hedges are able to provide a number of ecosystem services, including mitigation of rainfall, trapping of particulate pollution, local temperature regulation etc. Using hedges as a model, we argue that differences in plants’ capacity to provide environmental benefits should be taken into account, in addition to their suitability for particular conditions, ornamental appeal and cost, when choosing plants for green spaces. The overarching aim of our project is to quantify the simultaneous provision of multiple services by several widely used hedge species and cultivars. In this paper, we are focusing on the provision of rainfall capture by the hedges. The following species and cultivars, differing in the leaf and canopy structure and size, and in some physiological parameters, were chosen for the study: Photinia x fraseri 'Red Robin', Thuja plicata ‘Atrovirens’, Taxus baccata, Ligustrum ovalifolium ‘Aureum’ and ‘Argenteum’ and Cotoneaster franchetii. The experiments were conducted June-July 2015 in glasshouses at the University of Reading, UK. We measured the water use of different species/cultivars (6 plant ‘treatments’ and bare substrate as a control, in 10 L containers, with 6-8 replicates each) and their ability to hold water within the canopy. Plants’ leaf and root biomass and leaf area (LA) were also measured. Species/cultivars differed in the capacity of canopies to retain water after a simulated rainfall event. Ligustrum ‘Aureum’ held significantly more water within the canopy than other species/cultivars, despite not having the largest LA. Furthermore, when differences in LA were taken into the account, Cotoneaster, Thuja, Taxus and Ligustrum ‘Argenteum’ lost most water per unit leaf area suggesting that they have the greatest potential to restore soil’s capacity to receive subsequent rainfall. Our initial findings confirm the hypothesis that differences in plant structure and function lead to different capacities for rainfall capture. This could inform our planting choices and help to manage/reduce problems associated with excess rainfall
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