New and simple algorithms for stable flow problems

Stable flows generalize the well-known concept of stable matchings to markets in which transactions may involve several agents, forwarding flow from one to another. An instance of the problem consists of a capacitated directed network, in which vertices express their preferences over their incident edges. A network flow is stable if there is no group of vertices that all could benefit from rerouting the flow along a walk. Fleiner established that a stable flow always exists by reducing it to the stable allocation problem. We present an augmenting-path algorithm for computing a stable flow, the first algorithm that achieves polynomial running time for this problem without using stable allocation as a black-box subroutine. We further consider the problem of finding a stable flow such that the flow value on every edge is within a given interval. For this problem, we present an elegant graph transformation and based on this, we devise a simple and fast algorithm, which also can be used to find a solution to the stable marriage problem with forced and forbidden edges. Finally, we study the stable multicommodity flow model introduced by Kir\'{a}ly and Pap. The original model is highly involved and allows for commodity-dependent preference lists at the vertices and commodity-specific edge capacities. We present several graph-based reductions that show equivalence to a significantly simpler model. We further show that it is NP-complete to decide whether an integral solution exists

A cohort study of the impact of COVID-19 on the quality of life of people newly diagnosed with dementia and their family carers

Introduction COVID-19 has impacted people with dementia and their family carers, yet little is known about effects on overall quality of life. Methods In a UK cohort study, pre- and post-pandemic data were collected from 114 carers and 93 recently diagnosed people with dementia. Latent growth curve modeling examined change in quality of life. Results Carers reported significant decline in quality of life, although no change was demonstrated by people with dementia. In multivariable analyses, higher levels of cognitive impairment, deprivation, study site, and lower number of memory clinic contacts were associated with greater decline in carer quality of life. Discussion Maintaining life quality for people with dementia during the pandemic appears to have come at the expense of their family carers. This inequity has fallen hardest on those caring for people with more severe dementia, in deprived areas, and with least support from memory services. These effects may be prevented or reversed by post-diagnostic care

DETERMinants of quality of life, care and costs, and consequences of INequalities in people with dementia and their carers (DETERMIND): a protocol paper

Objectives: DETERMIND (DETERMinants of quality of life, care and costs, and consequences of INequalities in people with Dementia and their carers) is designed to address fundamental, and, as yet unanswered, questions about inequalities, outcomes and costs following diagnosis with dementia. These answers are needed to improve the quality of care and equity of access to care, and therefore the quality of life, of people with dementia and their carers. Method: DETERMIND is a programme of research consisting of seven complementary workstreams (WS) exploring various components that may result in unequal dementia care: WS1: Recruitment and follow-up of the DETERMIND cohort - 900 people with dementia and their carers from three geographically and socially diverse sites within six months following diagnosis, and follow them up for three years. WS2: Investigation of the extent of inequalities in access to dementia care WS3: Relationship between use and costs of services and outcomes WS4: Experiences of self-funders of care WS5: Decision-making processes for people with dementia and carers WS6: Effect of diagnostic stage and services on outcomes WS7: Theory of Change informed strategy and actions for applying the research findings Outcomes: During the life of the programme, analysing baseline results and then follow-up of the DETERMIND cohort over 3 years, we will establish evidence on current services and practice. DETERMIND will deliver novel, detailed data on inequalities in dementia care and what drives positive and negative outcomes and costs for people with dementia and carers, and identify factors that help or hinder living well with dementia

Transmitted drug resistance, selection of resistance mutations and moderate antiretroviral efficacy in HIV-2: Analysis of the HIV-2 Belgium and Luxembourg database

BACKGROUND: Guidelines established for the treatment of HIV-1 infection and genotype interpretation do not apply for HIV-2. Data about antiretroviral (ARV) drug efficacy and resistance mutations is scarce. METHODS: Clinical data about HIV-2 infected patients in Belgium and Luxembourg were collected and the effect of ARV therapy on plasma viral load and CD4 counts were analysed. Viral RNA encoding for protease (PR) and reverse transcriptase (RT) from ARV-naive and treated patients were sequenced. RESULTS: Sixty-five HIV-2 infected patients were included in this cohort. Twenty patients were treated with 25 different ARV combinations in a total of 34 regimens and six months after the start of ARV therapy, only one third achieved viral load suppression. All of these successful regimens bar one contained protease inhibitors (PIs). Mean CD4 gains in the group of viral load suppressors and the group of patients treated with PI-containing regimens were respectively significantly higher than in the group of non-suppressors and the group of PI-sparing regimens. The most frequent mutations selected under therapy (compared to HIV-2 ROD) were V71I, L90M and I89V within PR. Within RT, they were M184V, Q151M, V111I and K65R. All of these mutations, except K65R and M184V, were also found in variable proportions in ARV-naive patients. CONCLUSION: Despite a high rate of ARV treatment failure, better virological and immunological results were achieved with PI-containing regimens. The analysis of polymorphic positions and HIV-2 specific mutations selected during therapy showed for the first time that transmission of drug resistant viruses has occurred in Belgium and Luxembourg. The high heterogeneity in ARV combinations reflects a lack of guidelines for the treatment of HIV-2 infection

Is Pyroglutamic Acid a Prognostic Factor Among Patients with Suspected Infection? A Prospective Cohort Study

AbstractPyroglutamic acid (PGA) is a compound that accumulates during oxidative stress and hence, elevated levels may be associated with poor prognosis in patients with infection or sepsis. To examine this hypothesis, patients presenting with acute infection were recruited in the emergency department and prospectively followed for 30 days. Sport urine samples were quantified for PGA. Outcomes were mortality and composite outcome of death or organ failure. Thirty two (32%) patients had qSOFA≥2. Median urine PGA was 22.9 (IQR 17.64, 33.53) µmol/mmol creatinine. Four patients demonstrated PGA values ≥ 63 µmol/mmol creatinine. Univariate analysis showed that PGA concentration ≥ 75th percentile (i.e. 33.53 µmol/mmol creatinine) was associated with higher rates of in-hospital mortality (p = 0.041) with similar trend for PGA ≥ 63 µmol/mmol creatinine (p = 0.04). However, multivariate analysis showed that PGA was not associated with worse outcomes, whereas heart rate was associated with both composite outcomes (HR 1.0, p = 0.008 and HR 1.02, p = 0.001 for composite outcome with 30 days and in-hospital mortality, respectively). Among low risk patients, high PGA levels were consistently associated with worse outcomes. In conclusion, urine PGA concentration was not associated with worse outcomes among septic patients. Nevertheless, future studies should evaluate this association in larger cohorts.</jats:p

Optimization of chickpea irrigation in a semi-arid climate based on morpho-physiological parameters

ABSTRACTContextWhile the world population is steadily growing, the demand for plant-based protein in general, and chickpea in particular, is rising. Heatwaves and terminal drought are the main abiotic factors limiting chickpea yield worldwide.ObjectiveDeveloping better irrigation management for the chickpea agro-system can promote higher and more sustainable yields. Supplemental irrigation at the right timing and dose may increase yield dramatically.MethodsWe studied the response of a modern Kabuli chickpea cultivar to irrigation during the pod-filling period over three growing seasons (2019-2021) in northern Negev, Israel, under semi-arid conditions. Six irrigation treatments were applied based on crop coefficients (Kc) of 0, 0.5, 0.7, 1.0, 1.25, and 1.4 of crop evapotranspiration (ETc) as measured by a meteorological station on site. Morpho-physiological parameters and above-ground biomass accumulation were monitored throughout the cropping seasons, and the final grain yield was determined at maturation. Irrigation onset was determined based on the plants’ water potential (&gt; 15 bar).ResultsOur results indicate that optimal water status (as reflected by pressure chamber values) was in the range of 12-14 bar during the irrigation period. Irrigation according to evapotranspiration (ETc) with a crop coefficient factor (Kc) of 1.25 resulted in the highest grain yields over the three years. To ensure optimal water supply during the reproductive phase, one that is compatible with the crop water requirements, maintaining values of 25 mm node length above the Last Fully Developed Pod (LFDP) and a 90 mm distance between LFDP to the stem apex is recommended.ConclusionsIrrigation onset when the crop is already at mild drought stress, followed by sufficient irrigation while following the indicated morphology and water potential values, may help farmers optimize irrigation and maximize chickpea crop production.</jats:sec

Three-dimensional matching instances are rich in stable matchings

Extensive studies have been carried out on the Stable Matching problem, but they mostly consider cases where the agents to match belong to either one or two sets. Little work has been done on the three-set extension, despite the many applications in which three-dimensional stable matching (3DSM) can be used. In this paper we study the Cyclic 3DSM problem, a variant of 3DSM where agents in each set only rank the agents from one other set, in a cyclical manner. The question of whether every Cyclic 3DSM instance admits a stable matching has remained open for many years. We give the exact number of stable matchings for the class of Cyclic 3DSM instances where all agents in the same set share the same master preference list. This number is exponential in the size of the instances. We also show through empirical experiments that this particular class contains the most constrained Cyclic 3DSM instances, the ones with the fewest stable matchings. This would suggest that not only do all Cyclic 3DSM instances have at least one stable matching, but they each have an exponential number of them