68 research outputs found
A Simple Model for Solar Isorotational Contours
The solar convective zone, or SCZ, is nearly adiabatic and marginally
convectively unstable. But the SCZ is also in a state of differential rotation,
and its dynamical stability properties are those of a weakly magnetized gas.
This renders it far more prone to rapidly growing rotational baroclinic
instabilities than a hydrodynamical system would be. These instabilities should
be treated on the same footing as convective instabilites. If isentropic and
isorotational surfaces coincide in the SCZ, the gas is marginally (un)stable to
{\em both} convective and rotational disturbances. This is a plausible
resolution for the instabilities associated with these more general rotating
convective systems. This motivates an analysis of the thermal wind equation in
which isentropes and isorotational surfaces are identical. The characteristics
of this partial differential equation correspond to isorotation contours, and
their form may be deduced even without precise knowledge of how the entropy and
rotation are functionally related. Although the exact solution of the global
SCZ problem in principle requires this knowledge, even the simplest models
produce striking results in broad agreement with helioseismology data. This
includes horizontal (i.e. quasi-spherical) isorotational contours at the poles,
axial contours at the equator, and approximately radial contours at
midlatitudes. The theory does not apply directly to the tachocline, where a
simple thermal wind balance is not expected to be valid. The work presented
here is subject to tests of self-consistency, among them the prediction that
there should be good agreement between isentropes and isorotational contours in
sufficiently well-resolved large scale numerical MHD simulations.Comment: Final version: 21 pages, 4 figures, to appear in MNRAS; thorough
revision, typos and minor errors corrected, expanded development and
reordering of the material. Conclusions unchanged from origina
Magnetostrophic MRI in the Earth's Outer Core
We show that a simple, modified version of the Magnetorotational Instability
(MRI) can develop in the outer liquid core of the Earth, in the presence of a
background shear. It requires either thermal wind, or a primary instability,
such as convection, to drive a weak differential rotation within the core. The
force balance in the Earth's core is very unlike classical astrophysical
applications of the MRI (such as gaseous disks around stars). Here, the weak
differential rotation in the Earth core yields an instability by its
constructive interaction with the planet's much larger rotation rate. The
resulting destabilising mechanism is just strong enough to counteract
stabilizing resistive effects, and produce growth on geophysically interesting
timescales. We give a simple physical explanation of the instability, and show
that it relies on a force balance appropriate to the Earth's core, known as
magnetostrophic balance
Retail-led Regeneration and Store Switching Behaviour
Retail-led regeneration of ‘food deserts’ has become accepted policy in the UK, although the impacts of such stores remain under-researched. It is assumed that residents will switch their shopping behaviour to the new store and then alter their purchasing patterns to include more healthy options. A pre- and post ‘intervention’ study in a deprived area and an equally deprived non-intervention area of Glasgow finds that high switching rates to the new store were identified, indicating some success in altering shopping behaviours. Many switched from large food stores outside the area to shopping within the area. Dietary patterns in the intervention area were maintained after store development; store switching did not induce dietary switching. Results suggest policy should be based on attempting to change both shopping and purchasing behaviours rather than assuming the latter will automatically be transformed by new retail spaces and offers
Vertical monopoly power, profit and risk: The British beer industry, c.1970-2004
By investigating surplus and risk distribution in the British brewing industry, this paper shows that risk and risk transfer are important dimensions of vertical supply chain relationships. A comparative financial analysis shows the effects of models of vertical ownership before and after the break-up of producer controlled tenanted estates and the strategy and performance of pub-owning companies. Contrasting mechanisms for controlling the capture of surplus and division of risk are evaluated. The paper complements prior studies that have concentrated on the brewers by assessing winners and losers amongst pub owning companies and tenants in different models of vertical organisation and how they might be effectively regulated
Validating Health Impact Assessment: Prediction is difficult (especially about the future)
Health Impact Assessment (HIA) has been recommended as a means of estimating how policies, programmes and projects may impact on public health, and on health inequalities. This paper considers the difference between predicting health impacts, and measuring those impacts. It draws upon a case study of the building of a new hypermarket in a deprived area of Glasgow, which offered an opportunity to reflect on the issue of the predictive validity of HIA, and to consider the difference between potential and actual impacts. We found that the actual impacts of the new hypermarket on diet differed from that which would have been predicted based on previous studies. Furthermore they challenge current received wisdom about the impact of food retail outlets in poorer areas. These results are relevant to the validity of HIA as a process and emphasise the importance of further research on the predictive validity of HIA, which should help improve its value to decision-makers
Deep Underground Science and Engineering Laboratory - Preliminary Design Report
The DUSEL Project has produced the Preliminary Design of the Deep Underground
Science and Engineering Laboratory (DUSEL) at the rehabilitated former
Homestake mine in South Dakota. The Facility design calls for, on the surface,
two new buildings - one a visitor and education center, the other an experiment
assembly hall - and multiple repurposed existing buildings. To support
underground research activities, the design includes two laboratory modules and
additional spaces at a level 4,850 feet underground for physics, biology,
engineering, and Earth science experiments. On the same level, the design
includes a Department of Energy-shepherded Large Cavity supporting the Long
Baseline Neutrino Experiment. At the 7,400-feet level, the design incorporates
one laboratory module and additional spaces for physics and Earth science
efforts. With input from some 25 science and engineering collaborations, the
Project has designed critical experimental space and infrastructure needs,
including space for a suite of multidisciplinary experiments in a laboratory
whose projected life span is at least 30 years. From these experiments, a
critical suite of experiments is outlined, whose construction will be funded
along with the facility. The Facility design permits expansion and evolution,
as may be driven by future science requirements, and enables participation by
other agencies. The design leverages South Dakota's substantial investment in
facility infrastructure, risk retirement, and operation of its Sanford
Laboratory at Homestake. The Project is planning education and outreach
programs, and has initiated efforts to establish regional partnerships with
underserved populations - regional American Indian and rural populations
Missed Opportunities: Family History and Behavioral Risk Factors in Breast Cancer Risk Assessment Among a Multiethnic Group of Women
BACKGROUND: Clinician’s knowledge of a woman’s cancer family history (CFH) and counseling about health-related behaviors (HRB) is necessary for appropriate breast cancer care. OBJECTIVE: To evaluate whether clinicians solicit CFH and counsel women on HRB; to assess relationship of well visits and patient risk perception or worry with clinician’s behavior. DESIGN: Cross-sectional population-based telephone survey. PARTICIPANTS: Multiethnic sample; 1,700 women from San Francisco Mammography Registry with a screening mammogram in 2001–2002. MEASUREMENTS: Predictors: well visit in prior year, self-perception of 10-year breast cancer risk, worry scale. Outcomes: Patient report of clinician asking about CFH in prior year, or ever counseling about HRB in relation to breast cancer risk. Multivariate models included age, ethnicity, education, language of interview, insurance/mammography facility, well visit, ever having a breast biopsy/follow-up mammography, Gail-Model risk, Jewish heritage, and body mass index. RESULTS: 58% reported clinicians asked about CFH; 33% reported clinicians ever discussed HRB. In multivariate analysis, regardless of actual risk, perceived risk, or level of worry, having had a well visit in prior year was associated with increased odds (OR = 2.3; 95% CI 1.6, 3.3) that a clinician asked about CFH. Regardless of actual risk of breast cancer, a higher level of worry (OR = 1.9; 95% CI 1.4, 2.6) was associated with increased odds that a clinician ever discussed HRB. CONCLUSIONS: Clinicians are missing opportunities to elicit family cancer histories and counsel about health-related behaviors and breast cancer risk. Preventive health visits offer opportunities for clinicians to address family history, risk behaviors, and patients’ worries about breast cancer
Molecular Characterization of a 21.4 Kilobase Antibiotic Resistance Plasmid from an α-Hemolytic Escherichia coli O108:H- Human Clinical Isolate
This study characterizes the 21.4 kilobase plasmid pECTm80 isolated from Escherichia coli strain 80, an α hemolytic human clinical diarrhoeal isolate (serotype O108:H-). DNA sequence analysis of pECTm80 revealed it belonged to incompatibility group X1, and contained plasmid partition and toxin-antitoxin systems, an R6K-like triple origin (ori) replication system, genes required for replication regulation, insertion sequences IS1R, ISEc37 and a truncated transposase gene (Tn3-like ΔtnpA) of the Tn3 family, and carried a class 2 integron. The class 2 integron of pECTm80 contains an intact cassette array dfrA1-sat2, encoding resistance to trimethoprim and streptothricin, and an aadA1 gene cassette truncated by the insertion of IS1R. The complex plasmid replication system includes α, β and γ origins of replication. Pairwise BLASTn comparison of pECTm80 with plasmid pE001 reveals a conserved plasmid backbone suggestive of a common ancestral lineage. Plasmid pECTm80 is of potential clinical importance, as it carries multiple genes to ensure its stable maintenance through successive bacterial cell divisions and multiple antibiotic resistance genes
- …