4,754 research outputs found
Noncommutative geometry, topology and the standard model vacuum
As a ramification of a motivational discussion for previous joint work, in
which equations of motion for the finite spectral action of the Standard Model
were derived, we provide a new analysis of the results of the calculations
herein, switching from the perspective of Spectral triple to that of Fredholm
module and thus from the analogy with Riemannian geometry to the pre-metrical
structure of the Noncommutative geometry. Using a suggested Noncommutative
version of Morse theory together with algebraic -theory to analyse the
vacuum solutions, the first two summands of the algebra for the finite triple
of the Standard Model arise up to Morita equivalence. We also demonstrate a new
vacuum solution whose features are compatible with the physical mass matrix.Comment: 24 page
Conduction of topologically-protected charged ferroelectric domain walls
We report on the observation of nanoscale conduction at ferroelectric domain
walls in hexagonal HoMnO3 protected by the topology of multiferroic vortices
using in situ conductive atomic force microscopy, piezoresponse force
microscopy, and kelvin-probe force microscopy at low temperatures. In addition
to previously observed Schottky-like rectification at low bias [Phys. Rev.
Lett., 104, 217601 (2010)], conductance spectra reveal that negatively charged
tail-to-tail walls exhibit enhanced conduction at high forward bias, while
positively charged head-to-head walls exhibit suppressed conduction at high
reverse bias. Our results pave the way for understanding the semiconducting
properties of the domains and domain walls in small-gap ferroelectrics.Comment: 8 pages, 4 figure
Calculation of energy levels and transition amplitudes for barium and radium
The radium atom is a promising system for studying parity and time invariance
violating weak interactions. However, available experimental spectroscopic data
for radium is insufficient for designing an optimal experimental setup. We
calculate the energy levels and transition amplitudes for radium states of
significant interest. Forty states corresponding to all possible configurations
consisting of the , and single-electron states as well as the
states of the , and configurations have been calculated.
The energies of ten of these states corresponding to the , ,
, and configurations are not known from experiment. Calculations
for barium are used to control the accuracy.Comment: 12 pages, 4 table
Cost Effectiveness of First-Line Treatment with Doxorubicin/Ifosfamide Compared to Trabectedin Monotherapy in the Management of Advanced Soft Tissue Sarcoma in Italy, Spain, and Sweden
BACKGROUND: Doxorubicin/ifosfamide is a first-line systemic chemotherapy for the majority of advanced soft tissue sarcoma (ASTS) subtypes. Trabectedin is indicated for the treatment of ASTS after failure of anthracyclines and/or ifosfamide; however it is being increasingly used off-label as a first-line treatment. This study estimated the cost effectiveness of these two treatments in the first-line management of ASTS in Italy, Spain, and Sweden. METHODS: A Markov model was constructed to estimate the cost effectiveness of doxorubicin/ifosfamide compared to trabectedin monotherapy, defined as the cost per QALY gained, in each country. RESULTS: First-line treatment with doxorubicin/ifosfamide resulted in lower two-year healthcare costs and more QALYs than first-line treatment with trabectedin monotherapy in all three countries. Probabilistic sensitivity analysis showed that at a cost per QALY threshold of €35,000, >90% of a cohort would be cost effectively treated with doxorubicin/ifosfamide compared to trabectedin monotherapy in all three countries. CONCLUSION: Within the model’s limitations, first-line treatment of patients with ASTS with doxorubicin/ifosfamide instead of trabectedin monotherapy affords a cost-effective use of publicly funded healthcare resources in Italy, Spain, and Sweden and is therefore the preferred treatment in all three countries. These findings support the recommendation that trabectedin should remain a second-line treatment
A statistical evaluation of the effects of gender differences in assessment of acute inhalation toxicity
Acute inhalation toxicity of chemicals has conventionally been assessed by the median lethal concentration
(LC50) test (organisation for economic co-operation and development (OECD) TG 403). Two new methods,
the recently adopted acute toxic class method (ATC; OECD TG 436) and a proposed fixed concentration procedure
(FCP), have recently been considered, but statistical evaluations of these methods did not investigate
the influence of differential sensitivity between male and female rats on the outcomes. This paper presents an
analysis of data from the assessment of acute inhalation toxicity for 56 substances. Statistically significant differences
between the LC50 for males and females were found for 16 substances, with greater than 10-fold differences
in the LC50 for two substances. The paper also reports a statistical evaluation of the three test
methods in the presence of unanticipated gender differences. With TG 403, a gender difference leads to a
slightly greater chance of under-classification. This is also the case for the ATC method, but more pronounced
than for TG 403, with misclassification of nearly all substances from Globally Harmonised System (GHS) class 3
into class 4. As the FCP uses females only, if females are more sensitive, the classification is unchanged. If males
are more sensitive, the procedure may lead to under-classification. Additional research on modification of the
FCP is thus proposed
Multi-level decision-based system architecting
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 209-212).Decision-based system architecting represents a complex system as a set of interconnected decisions that a .system architect can make about the trade space. Modeling a system using decision-based frameworks allows the architect to not only enumerate and evaluate feasible architectures, but also, to gain insight into how influential each decision is to the overall system. A single-level decision-based model allows an architect to examine the decisions and architectural combinations at a single level of abstraction of the architecture. Through linking of multiple single-level models, each focusing at a different level of abstraction of the architecture, the system architect can gain insight into the decisions and options for system, element, and component designs while maintaining the validity of the decision support data provided by the models. Single and multi-level decision based system architecting is applied to multiple future human spaceflight projects. The architecture of the Lunar Surface System and the mission design for a human Near Earth Object (NEO) mission are examined through single-level models. The habitat design for potential NEO missions is further examined through the application of multi-level decision-based system architecting techniques.by Arthur N. Guest.S.M
Health economic burden that wounds impose on the National Health Service in the UK
OBJECTIVE: To estimate the prevalence of wounds managed by the UK's National Health Service (NHS) in 2012/2013 and the annual levels of healthcare resource use attributable to their management and corresponding costs. METHODS: This was a retrospective cohort analysis of the records of patients in The Health Improvement Network (THIN) Database. Records of 1000 adult patients who had a wound in 2012/2013 (cases) were randomly selected and matched with 1000 patients with no history of a wound (controls). Patients' characteristics, wound-related health outcomes and all healthcare resource use were quantified and the total NHS cost of patient management was estimated at 2013/2014 prices. RESULTS: Patients' mean age was 69.0 years and 45% were male. 76% of patients presented with a new wound in the study year and 61% of wounds healed during the study year. Nutritional deficiency (OR 0.53; p<0.001) and diabetes (OR 0.65; p<0.001) were independent risk factors for non-healing. There were an estimated 2.2 million wounds managed by the NHS in 2012/2013. Annual levels of resource use attributable to managing these wounds and associated comorbidities included 18.6 million practice nurse visits, 10.9 million community nurse visits, 7.7 million GP visits and 3.4 million hospital outpatient visits. The annual NHS cost of managing these wounds and associated comorbidities was pound5.3 billion. This was reduced to between pound5.1 and pound4.5 billion after adjusting for comorbidities. CONCLUSIONS: Real world evidence highlights wound management is predominantly a nurse-led discipline. Approximately 30% of wounds lacked a differential diagnosis, indicative of practical difficulties experienced by non-specialist clinicians. Wounds impose a substantial health economic burden on the UK's NHS, comparable to that of managing obesity ( pound5.0 billion). Clinical and economic benefits could accrue from improved systems of care and an increased awareness of the impact that wounds impose on patients and the NHS.Ye
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