72 research outputs found
The Hospitals/Residents Problem with Couples: complexity and integer programming models
The Hospitals / Residents problem with Couples (hrc) is a generalisation of the classical Hospitals / Residents problem (hr) that is important in practical applications because it models the case where couples submit joint preference lists over pairs of (typically geographically close) hospitals. In this paper we give a new NP-completeness result for the problem of deciding whether a stable matching exists, in highly restricted instances of hrc, and also an inapproximability bound for finding a matching with the minimum number of blocking pairs in equally restricted instances of hrc. Further, we present a full description of the first Integer Programming model for finding a maximum cardinality stable matching in an instance of hrc and we describe empirical results when this model applied to randomly generated instances of hrc
Grain growth in nanocrystalline copper thin films investigated by non-ambient X-ray diffraction measurements
Signatures of the excitonic memory effects in four-wave mixing processes in cavity polaritons
We report the signatures of the exciton correlation effects with finite
memory time in frequency domain degenerate four-wave mixing (DFWM) in
semiconductor microcavity. By utilizing the polarization selection rules, we
discriminate instantaneous, mean field interactions between excitons with the
same spins, long-living correlation due to the formation of biexciton state by
excitons with opposite spins, and short-memory correlation effects in the
continuum of unbound two-exciton states. The DFWM spectra give us the relative
contributions of these effects and the upper limit for the time of the
exciton-exciton correlation in the unbound two-exciton continuum. The obtained
results reveal the basis of the cavity polariton scattering model for the DFWM
processes in high-Q GaAs microcavity.Comment: 11 pages, 1 figur
Views of the Chiral Magnetic Effect
My personal views of the Chiral Magnetic Effect are presented, which starts
with a story about how we came up with the electric-current formula and
continues to unsettled subtleties in the formula. There are desirable features
in the formula of the Chiral Magnetic Effect but some considerations would lead
us to even more questions than elucidations. The interpretation of the produced
current is indeed very non-trivial and it involves a lot of confusions that
have not been resolved.Comment: 19 pages, no figure; typos corrected, references significantly
updated, to appear in Lect. Notes Phys. "Strongly interacting matter in
magnetic fields" (Springer), edited by D. Kharzeev, K. Landsteiner, A.
Schmitt, H.-U. Ye
Genetic variation at MECOM, TERT, JAK2 and HBS1L-MYB predisposes to myeloproliferative neoplasms
Clonal proliferation in myeloproliferative neoplasms (MPN) is driven by somatic mutations in JAK2, CALR or MPL, but the contribution of inherited factors is poorly characterized. Using a three-stage genome-wide association study of 3,437 MPN cases and 10,083 controls, we identify two SNPs with genome-wide significance in JAK2V617F-negative MPN: rs12339666 (JAK2; meta-analysis P=1.27 × 10−10) and rs2201862 (MECOM; meta-analysis P=1.96 × 10−9). Two additional SNPs, rs2736100 (TERT) and rs9376092 (HBS1L/MYB), achieve genome-wide significance when including JAK2V617F-positive cases. rs9376092 has a stronger effect in JAK2V617F-negative cases with CALR and/or MPL mutations (Breslow–Day P=4.5 × 10−7), whereas in JAK2V617F-positive cases rs9376092 associates with essential thrombocythemia (ET) rather than polycythemia vera (allelic χ2 P=7.3 × 10−7). Reduced MYB expression, previously linked to development of an ET-like disease in model systems, associates with rs9376092 in normal myeloid cells. These findings demonstrate that multiple germline variants predispose to MPN and link constitutional differences in MYB expression to disease phenotype
Effects of rare kidney diseases on kidney failure: a longitudinal analysis of the UK National Registry of Rare Kidney Diseases (RaDaR) cohort
Background
Individuals with rare kidney diseases account for 5–10% of people with chronic kidney disease, but constitute more than 25% of patients receiving kidney replacement therapy. The National Registry of Rare Kidney Diseases (RaDaR) gathers longitudinal data from patients with these conditions, which we used to study disease progression and outcomes of death and kidney failure.
Methods
People aged 0–96 years living with 28 types of rare kidney diseases were recruited from 108 UK renal care facilities. The primary outcomes were cumulative incidence of mortality and kidney failure in individuals with rare kidney diseases, which were calculated and compared with that of unselected patients with chronic kidney disease. Cumulative incidence and Kaplan–Meier survival estimates were calculated for the following outcomes: median age at kidney failure; median age at death; time from start of dialysis to death; and time from diagnosis to estimated glomerular filtration rate (eGFR) thresholds, allowing calculation of time from last eGFR of 75 mL/min per 1·73 m2 or more to first eGFR of less than 30 mL/min per 1·73 m2 (the therapeutic trial window).
Findings
Between Jan 18, 2010, and July 25, 2022, 27 285 participants were recruited to RaDaR. Median follow-up time from diagnosis was 9·6 years (IQR 5·9–16·7). RaDaR participants had significantly higher 5-year cumulative incidence of kidney failure than 2·81 million UK patients with all-cause chronic kidney disease (28% vs 1%; p<0·0001), but better survival rates (standardised mortality ratio 0·42 [95% CI 0·32–0·52]; p<0·0001). Median age at kidney failure, median age at death, time from start of dialysis to death, time from diagnosis to eGFR thresholds, and therapeutic trial window all varied substantially between rare diseases.
Interpretation
Patients with rare kidney diseases differ from the general population of individuals with chronic kidney disease: they have higher 5-year rates of kidney failure but higher survival than other patients with chronic kidney disease stages 3–5, and so are over-represented in the cohort of patients requiring kidney replacement therapy. Addressing unmet therapeutic need for patients with rare kidney diseases could have a large beneficial effect on long-term kidney replacement therapy demand.
Funding
RaDaR is funded by the Medical Research Council, Kidney Research UK, Kidney Care UK, and the Polycystic Kidney Disease Charity
Nitrate reductase activity in Paul's scarlet rose suspension cultures and the differential role of nitrate and molybdenum in induction
Associations between perceived neighbourhood problems and quality of life in older adults with and without osteoarthritis: results from the Hertfordshire Cohort Study
This study examined whether the association of quality of life (QoL) with perceived neighbourhood problems is stronger in older adults with osteoarthritis (OA) than in those without OA. Of all 294 participants, 23.8% had OA. More perceived neighbourhood problems were associated with a stronger decrease in QoL over time in participants with OA (B=-0.018; p=0.02) than in those without OA (B=-0.004; p=0.39). Physical activity did not mediate this relationship. Older adults with OA may be less able to deal with more challenging environments
Existence of optimal strategies in linear multisector models
Endogenous growth, Optimal control with mixed constraints, von Neumann growth model,
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