5,526 research outputs found
Changes over time in socioeconomic inequalities in breast and rectal cancer survival in England and Wales during a 32-year period (1973-2004): the potential role of health care.
BACKGROUND: Socioeconomic inequalities in cancer survival are well documented but they vary for different cancers and over time. Reasons for these differences are poorly understood. PATIENTS AND METHODS: For England and Wales, we examined trends in socioeconomic survival inequalities for breast cancer in women and rectal cancer in men during the 32-year period 1973-2004. We used a theoretical framework based on Victora's 'inverse equity' law, under which survival inequalities could change with the advent of successive new treatments, of varying effectiveness, which are disseminated with different speed among patients of different socioeconomic groups. We estimated 5-year relative survival for patients of different deprivation quintiles and examined trends in survival inequalities in light of major treatment innovations. RESULTS: Inequalities in breast cancer survival (921,611 cases) narrowed steadily during the study (from -10% to -6%). In contrast, inequalities in rectal cancer survival (187,104 cases) widened overall (form -5% to -11%) with fluctuating periods of narrowing inequality. CONCLUSIONS: Trends in socioeconomic differences in tumour or patient factors are unlikely explanations of observed changes over time in survival inequalities. The sequential introduction into clinical practice of new treatments of progressively smaller incremental benefit may partly explain the reduction in inequality in breast cancer survival
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Up and away: ontogenic transference as a pathway for aerial dispersal of microplastics
Microplastics (MPs) are ubiquitous pollutants found in marine, freshwater and terrestrial ecosystems. With so many MPs in aquatic systems it is inevitable that they will be ingested by aquatic organisms, and be transferred up through the food chain. However, to date, no study has considered whether MPs can be transmitted by means of ontogenic transference i.e. between life stages that utilise different habitats. Here, we determine whether fluorescent polystyrene beads could transfer between Culex mosquito life stages and, particularly, could move into the flying adult stage. We show for the first time that MPs can be transferred ontogenically from a feeding (larva) into a non-feeding (pupa) life stage and subsequently into the adult terrestrial life stage. However, transference is dependent on particle size, with smaller 2 µm MPs transferring readily into pupae and adult stages, whilst 15 µm MPs transferred at a significantly reduced rate. Microplastics appear to accumulate in the Malpighian tubule renal excretion system. The transfer of MPs to the adults represents a potential aerial pathway to contamination of new environments. Thus, any organism that feeds on terrestrial life phases of freshwater insects could be impacted by MPs found in aquatic ecosystems
Thermodynamics of Dyonic Lifshitz Black Holes
Black holes with asymptotic anisotropic scaling are conjectured to be gravity
duals of condensed matter system close to quantum critical points with
non-trivial dynamical exponent z at finite temperature. A holographic
renormalization procedure is presented that allows thermodynamic potentials to
be defined for objects with both electric and magnetic charge in such a way
that standard thermodynamic relations hold. Black holes in asymptotic Lifshitz
spacetimes can exhibit paramagnetic behavior at low temperature limit for
certain values of the critical exponent z, whereas the behavior of AdS black
holes is always diamagnetic.Comment: 26 pages, 4 figure
Field-induced quantum fluctuations in the heavy fermion superconductor CeCu2Ge2
Quantum-mechanical fluctuations in strongly correlated electron systems cause
unconventional phenomena such as non-Fermi liquid behavior, and arguably high
temperature superconductivity. Here we report the discovery of a field-tuned
quantum critical phenomenon in stoichiometric CeCu2Ge2, a spin density wave
ordered heavy fermion metal that exhibits unconventional superconductivity
under ~ 10 GPa of applied pressure. Our finding of the associated quantum
critical spin fluctuations of the antiferromagnetic spin density wave order,
dominating the local fluctuations due to single-site Kondo effect, provide new
information about the underlying mechanism that can be important in
understanding superconductivity in this novel compound.Comment: Heavy Fermion, Quantum Critical Phenomeno
Large, high quality single-crystals of the new Topological Kondo Insulator, SmB6
SmB6 has recently been predicted to be a Topological Kondo Insulator, the first strongly correlated heavy fermion material to exhibit topological surface states. High quality crystals are necessary to investigate the topological properties of this material. Single crystal growth of the rare earth hexaboride, SmB6, has been carried out by the floating zone technique using a high power xenon arc lamp image furnace. Large, high quality single-crystals are obtained by this technique. The crystals produced by the floating zone technique are free of contamination from flux materials and have been characterised by resistivity and magnetisation measurements. These crystals are ideally suited for the investigation of both the surface and bulk properties of SmB6
Sine-Gordon Model - Renormalization Group Solutions and Applications
The sine-Gordon model is discussed and analyzed within the framework of the
renormalization group theory. A perturbative renormalization group procedure is
carried out through a decomposition of the sine-Gordon field in slow and fast
modes. An effective slow modes's theory is derived and re-scaled to obtain the
model's flow equations. The resulting Kosterlitz-Thouless phase diagram is
obtained and discussed in detail. The theory's gap is estimated in terms of the
sine-Gordon model paramaters. The mapping between the sine-Gordon model and
models for interacting electrons in one dimension, such as the g-ology model
and Hubbard model, is discussed and the previous renormalization group results,
obtained for the sine-Gordon model, are thus borrowed to describe different
aspects of Luttinger liquid systems, such as the nature of its excitations and
phase transitions. The calculations are carried out in a thorough and
pedagogical manner, aiming the reader with no previous experience with the
sine-Gordon model or the renormalization group approach.Comment: 44 pages, 7 figure
Controlling the Optical Properties of a Conjugated Co-polymer through Variation of Backbone Isomerism and the Introduction of Carbon Nanotubes
The need to control the formation of weakly emitting species in polymers such as aggregates and excimers, which are normally detrimental to device performance, is illustrated for the example of the polymer poly(m-phenylenevinylene-co-2,5-dioctyloxy-p-phenylenevinylene), using the model compound, 2,5-dioctyloxy-p-distyrylbenzene as a comparison. Two different methods, namely a Homer-Emmons polycondensation in dimethylformamide (DMF) and a Wittig polycondensation in dry toluene, have been used during synthesis resulting in a polymer with a predominantly trans-vinylene backbone and a polymer with a predominantly cis-vinylene backbone, respectively. Photoluminescence and absorption spectroscopy indicate that the polymer forms aggregate species in solution with spectra that are distinctly red-shifted from those associated with the intra-chain exciton. Concentration dependent optical studies were used to probe the evolution of aggregation in solution for both polymers. The results indicate that inter-chain coupling in the predominantly cis-polymer is prominent at lower concentrations than in the case of the trans-counterpart. These results are supported by pico-second pump and probe transient absorption measurements where, in dilute solutions, the polymer in a cis-configuration exhibits highly complex excited state dynamics, whereas the polymer in a trans-configuration behaves similarly to the model compound. It is proposed therefore that the degree of backbone isomerism has a profound impact on the morphology of the polymeric solid and control over it is a route towards optimising the performance of the material in thin film form. Another method to inhibit inter-chain effects using multi walled carbon nanotubes (MWNT) as nano-spacers in the polymer solutions is proposed. By comparison to spectroscopic analysis, aggregation effects are shown to be reduced by the introduction of nanotubes. Electron microscopy and computer simulation suggest a well-defined interaction between the polymer backbone and the lattice of the nanotube
Documenting the NICU design dilemma: parent and staff perceptions of open ward versus single family room units
Objective: With neonatal intensive care units (NICUs) evolving from multipatient wards toward family-friendly, single-family room units, the study objective was to compare satisfaction levels of families and health-care staff across these differing NICU facility designs.
Study Design: This prospective study documented, by means of institutional review board-approved questionnaire survey protocols, the perceptions of parents and staff from two contrasting NICU environments.
Result: Findings showed that demographic subgroups of parents and staff perceived the advantages and disadvantages of the two facility designs differently. Staff perceptions varied with previous experience, acclimation time and employment position, whereas parental perceptions revealed a naiveté bias through surveys of transitional parents with experience in both NICU facilities.
Conclusion: Use of transitional parent surveys showed a subject naiveté bias inherent in perceptions of inexperienced parents. Grouping all survey participants demographically provided more informative interpretations of data, and revealed staff perceptions to vary with position, previous training and hospital experience
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