741 research outputs found
Logics of Finite Hankel Rank
We discuss the Feferman-Vaught Theorem in the setting of abstract model
theory for finite structures. We look at sum-like and product-like binary
operations on finite structures and their Hankel matrices. We show the
connection between Hankel matrices and the Feferman-Vaught Theorem. The largest
logic known to satisfy a Feferman-Vaught Theorem for product-like operations is
CFOL, first order logic with modular counting quantifiers. For sum-like
operations it is CMSOL, the corresponding monadic second order logic. We
discuss whether there are maximal logics satisfying Feferman-Vaught Theorems
for finite structures.Comment: Appeared in YuriFest 2015, held in honor of Yuri Gurevich's 75th
birthday. The final publication is available at Springer via
http://dx.doi.org/10.1007/978-3-319-23534-9_1
Radiative Transfer for Exoplanet Atmospheres
Remote sensing of the atmospheres of distant worlds motivates a firm
understanding of radiative transfer. In this review, we provide a pedagogical
cookbook that describes the principal ingredients needed to perform a radiative
transfer calculation and predict the spectrum of an exoplanet atmosphere,
including solving the radiative transfer equation, calculating opacities (and
chemistry), iterating for radiative equilibrium (or not), and adapting the
output of the calculations to the astronomical observations. A review of the
state of the art is performed, focusing on selected milestone papers.
Outstanding issues, including the need to understand aerosols or clouds and
elucidating the assumptions and caveats behind inversion methods, are
discussed. A checklist is provided to assist referees/reviewers in their
scrutiny of works involving radiative transfer. A table summarizing the
methodology employed by past studies is provided.Comment: 7 pages, no figures, 1 table. Filled in missing information in
references, main text unchange
An investigation of the apparent breast cancer epidemic in France: screening and incidence trends in birth cohorts
<p>Abstract</p> <p>Background</p> <p>Official descriptive data from France showed a strong increase in breast-cancer incidence between 1980 to 2005 without a corresponding change in breast-cancer mortality. This study quantifies the part of incidence increase due to secular changes in risk factor exposure and in overdiagnosis due to organised or opportunistic screening. Overdiagnosis was defined as non progressive tumours diagnosed as cancer at histology or progressive cancer that would remain asymptomatic until time of death for another cause.</p> <p>Methods</p> <p>Comparison between age-matched cohorts from 1980 to 2005. All women residing in France and born 1911-1915, 1926-1930 and 1941-1945 are included. Sources are official data sets and published French reports on screening by mammography, age and time specific breast-cancer incidence and mortality, hormone replacement therapy, alcohol and obesity. Outcome measures include breast-cancer incidence differences adjusted for changes in risk factor distributions between pairs of age-matched cohorts who had experienced different levels of screening intensity.</p> <p>Results</p> <p>There was an 8-fold increase in the number of mammography machines operating in France between 1980 and 2000. Opportunistic and organised screening increased over time. In comparison to age-matched cohorts born 15 years earlier, recent cohorts had adjusted incidence proportion over 11 years that were 76% higher [95% confidence limits (CL) 67%, 85%] for women aged 50 to 64 years and 23% higher [95% CL 15%, 31%] for women aged 65 to 79 years. Given that mortality did not change correspondingly, this increase in adjusted 11 year incidence proportion was considered as an estimate of overdiagnosis.</p> <p>Conclusions</p> <p>Breast cancer may be overdiagnosed because screening increases diagnosis of slowly progressing non-life threatening cancer and increases misdiagnosis among women without progressive cancer. We suggest that these effects could largely explain the reported "epidemic" of breast cancer in France. Better predictive classification of tumours is needed in order to avoid unnecessary cancer diagnoses and subsequent procedures.</p
The results of arthroscopic anterior stabilisation of the shoulder using the bioknotless anchor system
<p>Abstract</p> <p>Background</p> <p>Shoulder instability is a common condition, particularly affecting a young, active population. Open capsulolabral repair is effective in the majority of cases, however arthroscopic techniques, particularly using suture anchors, are being used with increasing success.</p> <p>Methods</p> <p>15 patients with shoulder instability were operated on by a single surgeon (VK) using BioKnotless anchors (DePuy Mitek, Raynham, MA). The average length of follow-up was 21 months (17 to 31) with none lost to follow-up. Constant scores in both arms, patient satisfaction, activity levels and recurrence of instability was recorded.</p> <p>Results</p> <p>80% of patients were satisfied with their surgery. 1 patient suffered a further dislocation and another had recurrent symptomatic instability. The average constant score returned to 84% of that measured in the opposite (unaffected) shoulder. There were no specific post-operative complications encountered.</p> <p>Conclusion</p> <p>In terms of recurrence of symptoms, our results show success rates comparable to other methods of shoulder stabilisation. This technique is safe and surgeons familiar with shoulder arthroscopy will not encounter a steep learning curve. Shoulder function at approximately 2 years post repair was good or excellent in the majority of patients and it was observed that patient satisfaction was correlated more with return to usual activities than recurrence of symptoms.</p
The contribution of home-based technology to older people's quality of life in extra care housing
<p>Abstract</p> <p>Background</p> <p>British government policy for older people focuses on a vision of active ageing and independent living. In the face of diminishing personal capacities, the use of appropriate home-based technology (HBT) devices could potentially meet a wide range of needs and consequently improve many aspects of older people's quality of life such as physical health, psychosocial well-being, social relationships, and their physical or living environment. This study aimed to examine the use of HBT devices and the correlation between use of such devices and quality of life among older people living in extra-care housing (ECH).</p> <p>Methods</p> <p>A structured questionnaire was administered for this study. Using purposive sampling 160 older people living in extra-care housing schemes were selected from 23 schemes in England. A face-to-face interview was conducted in each participant's living unit. In order to measure quality of life, the SEIQoL-Adapted and CASP-19 were used.</p> <p>Results</p> <p>Although most basic appliances and emergency call systems were used in the living units, communally provided facilities such as personal computers, washing machines, and assisted bathing equipment in the schemes were not well utilised. Multiple regression analysis adjusted for confounders including age, sex, marital status, living arrangement and mobility use indicated a coefficient of 1.17 with 95% CI (0.05, 2.29) and <it>p </it>= 0.04 [SEIQoL-Adapted] and 2.83 with 95% CI (1.17, 4.50) and <it>p </it>= 0.001 [CASP-19].</p> <p>Conclusions</p> <p>The findings of the present study will be value to those who are developing new form of specialised housing for older people with functional limitations and, in particular, guiding investments in technological aids. The results of the present study also indicate that the home is an essential site for developing residential technologies.</p
Genetic polymorphisms in the matrix metalloproteinase 12 gene (MMP12) and breast cancer risk and survival: the Shanghai Breast Cancer Study
INTRODUCTION: Matrix metalloproteinase 12 (MMP12) is a proteolytic enzyme responsible for cleavage of plasminogen to angiotensin, which has an angiostatic effect. Using data from a population-based case–control study conducted among Chinese women in Shanghai, we evaluated the association of breast cancer risk and survival with two common polymorphisms in the MMP12 gene: A-82G in the promoter region and A1082G in exon, resulting in an amino acid change of asparagine to serine. METHODS: Included in the study were 1,129 cases and 1,229 age-frequency-matched population controls. Breast cancer patients were followed up to determine the intervals of overall survival and disease-free survival. RESULTS: The frequencies of the G allele in the A-82G and A1082G polymorphism among controls were 0.029 and 0.107, respectively. There were no associations between MMP12 polymorphisms and breast cancer risk. Patients with the AG or GG genotype of the A1082G polymorphism showed poorer overall survival (though the difference was not statistically significant) than patients with the AA genotype (hazard ratio 1.36, 95% CI 0.92 to 2.00). CONCLUSION: This result suggests that MMP12 A1082G polymorphism may be related to prognosis in breast cancer patients. Additional studies with larger sample sizes are warranted
Equivalence and noninferiority trials – are they viable alternatives for registration of new drugs? (III)
The scientific community's reliance on active-controlled trials is steadily increasing, as widespread agreement emerges concerning the role of these trials as viable alternatives to placebo trials. These trials present substantial challenges with regard to design and interpretation as their complexity increases, and the potential need for larger sample sizes impacts the cost and time variables of the drug development process. The potential efficacy and safety benefits derived from these trials may never be demonstrated by other methods. Active-controlled trials can develop valuable data to inform both prescribers and patients about the dose- and time-dependent actions of any new drug and can contribute to the management and communication of risks associated with the relevant therapeutic products
Type Ia Supernovae as Stellar Endpoints and Cosmological Tools
Empirically, Type Ia supernovae are the most useful, precise, and mature
tools for determining astronomical distances. Acting as calibrated candles they
revealed the presence of dark energy and are being used to measure its
properties. However, the nature of the SN Ia explosion, and the progenitors
involved, have remained elusive, even after seven decades of research. But now
new large surveys are bringing about a paradigm shift --- we can finally
compare samples of hundreds of supernovae to isolate critical variables. As a
result of this, and advances in modeling, breakthroughs in understanding all
aspects of SNe Ia are finally starting to happen.Comment: Invited review for Nature Communications. Final published version.
Shortened, update
Social sciences research in neglected tropical diseases 2: A bibliographic analysis
The official published version of the article can be found at the link below.Background
There are strong arguments for social science and interdisciplinary research in the neglected tropical diseases. These diseases represent a rich and dynamic interplay between vector, host, and pathogen which occurs within social, physical and biological contexts. The overwhelming sense, however, is that neglected tropical diseases research is a biomedical endeavour largely excluding the social sciences. The purpose of this review is to provide a baseline for discussing the quantum and nature of the science that is being conducted, and the extent to which the social sciences are a part of that.
Methods
A bibliographic analysis was conducted of neglected tropical diseases related research papers published over the past 10 years in biomedical and social sciences. The analysis had textual and bibliometric facets, and focussed on chikungunya, dengue, visceral leishmaniasis, and onchocerciasis.
Results
There is substantial variation in the number of publications associated with each disease. The proportion of the research that is social science based appears remarkably consistent (<4%). A textual analysis, however, reveals a degree of misclassification by the abstracting service where a surprising proportion of the "social sciences" research was pure clinical research. Much of the social sciences research also tends to be "hand maiden" research focused on the implementation of biomedical solutions.
Conclusion
There is little evidence that scientists pay any attention to the complex social, cultural, biological, and environmental dynamic involved in human pathogenesis. There is little investigator driven social science and a poor presence of interdisciplinary science. The research needs more sophisticated funders and priority setters who are not beguiled by uncritical biomedical promises
Evaluation of the current knowledge limitations in breast cancer research: a gap analysis
BACKGROUND
A gap analysis was conducted to determine which areas of breast cancer research, if targeted by researchers and funding bodies, could produce the greatest impact on patients.
METHODS
Fifty-six Breast Cancer Campaign grant holders and prominent UK breast cancer researchers participated in a gap analysis of current breast cancer research. Before, during and following the meeting, groups in seven key research areas participated in cycles of presentation, literature review and discussion. Summary papers were prepared by each group and collated into this position paper highlighting the research gaps, with recommendations for action.
RESULTS
Gaps were identified in all seven themes. General barriers to progress were lack of financial and practical resources, and poor collaboration between disciplines. Critical gaps in each theme included: (1) genetics (knowledge of genetic changes, their effects and interactions); (2) initiation of breast cancer (how developmental signalling pathways cause ductal elongation and branching at the cellular level and influence stem cell dynamics, and how their disruption initiates tumour formation); (3) progression of breast cancer (deciphering the intracellular and extracellular regulators of early progression, tumour growth, angiogenesis and metastasis); (4) therapies and targets (understanding who develops advanced disease); (5) disease markers (incorporating intelligent trial design into all studies to ensure new treatments are tested in patient groups stratified using biomarkers); (6) prevention (strategies to prevent oestrogen-receptor negative tumours and the long-term effects of chemoprevention for oestrogen-receptor positive tumours); (7) psychosocial aspects of cancer (the use of appropriate psychosocial interventions, and the personal impact of all stages of the disease among patients from a range of ethnic and demographic backgrounds).
CONCLUSION
Through recommendations to address these gaps with future research, the long-term benefits to patients will include: better estimation of risk in families with breast cancer and strategies to reduce risk; better prediction of drug response and patient prognosis; improved tailoring of treatments to patient subgroups and development of new therapeutic approaches; earlier initiation of treatment; more effective use of resources for screening populations; and an enhanced experience for people with or at risk of breast cancer and their families. The challenge to funding bodies and researchers in all disciplines is to focus on these gaps and to drive advances in knowledge into improvements in patient care
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