659 research outputs found

    Different degrees of career success: social origin and graduates’ education and labour market trajectories

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    Most research on social inequalities in higher education (HE) graduates’ labour market outcomes has analysed outcomes at one or two points in time, thus providing only snapshots of graduates’ occupational destinations. This study contributes to the existing literature by examining the education and labour market trajectories of degree holders across their life course and how these trajectories vary by social class of origin. We analyse data from the 1970 British Cohort Study and employ sequence analysis, followed by cluster analysis, to identify HE graduates’ typical trajectories. We assess the degree of social inequalities in the chance of following more or less advantaged pathways from age 16 up to the age of 42 and the extent to which these inequalities are explained by differences in higher education experiences. The results show that graduates from lower social classes of origin have more diverse and less stable trajectories, are less likely to enter top-level jobs in their 20s and more likely to enter and remain in lower social classes than their more socially advantaged counterparts. The age at which people graduate from HE emerges to be a key factor in explaining some of these patterns. Interestingly, HE factors - such as class of degree, fields of study and type of university attended - only partially explain social class differences. Our research provides new insights into the dynamic nature of inequalities among graduates showing that not only does the final destination matter but also the timing and sequencing of spells within the trajectories are important

    On the Finite-Time Behavior of Suboptimal Linear Model Predictive Control

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    Inexact methods for model predictive control (MPC), such as real-time iterative schemes or time-distributed optimization, alleviate the computational burden of exact MPC by providing suboptimal solutions. While the asymptotic stability of such algorithms is well studied, their finite-time performance has not received much attention. In this work, we quantify the performance of suboptimal linear model predictive control in terms of the additional closed-loop cost incurred due to performing only a finite number of optimization iterations. Leveraging this novel analysis framework, we propose a novel suboptimal MPC algorithm with a diminishing horizon length and finite-time closed-loop performance guarantees. This analysis allows the designer to plan a limited computational power budget distribution to achieve a desired performance level. We provide numerical examples to illustrate the algorithm's transient behavior and computational complexity.Comment: Accepted for Publication at the 62nd IEEE Conference on Decision and Control (CDC), Singapore, 202

    Heavy metal distribution in a sediment phytoremediation system at pilot scale

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    The continuous stream of polluted sediments, dredged from harbors and water bodies in order to maintain the navigation, is a common practice, but the fate of these sediments is an issue recognized worldwide. This pilot case study evaluated the application of phytoremediation as sustainable management strategy for the decontamination of polluted dredged marine sediments. The synergic action of different plant species (Paspalum vaginatum; P. vaginatum + Spartium junceum and P. vaginatum + Tamarix gallica) and organic matter (compost) in removing both heavy metals (Cd, Ni, Zn, Pb and Cu) and total petroleum hydrocarbons, and in recovering the nutritive and biological sediment properties were evaluated. In addition to the detection of total metal removal efficiency, the chemical distribution of metals in the sediment phases (exchangeable, manganese and iron oxides, organic matter and residual minerals) was also measured in order to make a more realistic estimation of the phytoremediation efficiency for the sediment decontamination. Finally, a complete picture of the metal flux was obtained by investigating the metal mass-balance in the treated sediments. The results of metal content in the sediment phases showed that metal distribution was not uniform and each metal predominated in different fractions; the solubility of metals in the sediment in the decreasing order was: Cd>Zn>Cu>Pb>Ni. The higher proportion of Ni and Pb in the residual phase can be the reason of the lower translocation of these metals in the plant tissues. On the other hand, Cd, Zn and Cu were the metals most easily translocated in plant tissues, both aboveground and roots, confirming their higher availability for the plants. The results of mass balance indicated that, at the end of the experimentation, a high content of metals were still found in the sediment. The greatest contribution in metal removal was attributed to a phytostabilization process at rhizosphere level followed by gravel and sand absorption. The capacity of rhizophere to precipitate heavy metals, could be considered as an alternative option for reducing the metal availability and, consequently, the toxicity in contaminated sediments

    Dynamics of a structured slug population model in the absence of seasonal variation

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    We develop a novel, nonlinear structured population model for the slug Deroceras reticulatum, a highly significant agricultural pest of great economic impact, in both organic and non-organic settings. In the absence of seasonal variations, we numerically explore the effect of life history traits that are dependent on an individual's size and measures of population biomass. We conduct a systematic exploration of parameter space and highlight the main mechanisms and implications of model design. A major conclusion of this work is that strong size dependent predation significantly adjusts the competitive balance, leading to non-monotonic steady state solutions and slowly decaying transients consisting of distinct generational cycles. Furthermore, we demonstrate how a simple ratio of adult to juvenile biomass can act as a useful diagnostic to distinguish between predated and non-predated environments, and may be useful in agricultural settings

    New Oral Anticoagulants Versus Warfarin in Atrial Fibrillation After Early Postoperative Period in Patients With Bioprosthetic Aortic Valve

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    Background: The efficacy of novel nonvitamin K antagonist oral anticoagulants (NOACs) in nonvalvular atrial fibrillation (AF) to prevent stroke is well assessed, but NOACs use in AF that occurs after bioprosthetic aortic valve replacement (AVR) is not endorsed. This retrospective real-world study evaluated the efficacy and safety of NOACs prescribed no earlier than 4 months after AVR as an alternative to warfarin in patients with AF. Methods: We pooled 1032 patients from the databases of 5 centers. Ischemic/embolic events and major bleeding rates were compared between 340 patients assuming NOACs and 692 prescribed warfarin. Propensity score matching was performed to avoid the bias between groups. Results: The NOACs vs warfarin embolic/ischemic rate was 13.5% (46 of 340) vs 22.7% (157 of 692), respectively, (hazard ratio [HR], 0.5; 95% confidence interval [CI], 0.37-0.75; P < .001), and the incidence rate was 3.7% vs 6.9% patients/year, respectively (log-rank test P = .009). The major bleeding rate was 7.3% (25 of 340) vs 13% (90 of 692) (HR, 0.5; 95% CI, 0.33-0.84; P = .007), and the incidence rate was 2% vs 4% patients/year (log-rank test P = .002.) After propensity score matching, the NOACs vs warfarin embolic/ischemic rate was 13.1% (42 of 321) vs 21.8% (70 of 321) (HR, 0.6; 95% CI, 0.4-0.9; P = .02), and the incidence rate was 4.1% vs 6.7% patients/year (log rank test P = .01). The major bleeding rate was 7.8% (25 of /321) vs 13.7% (44 of 321) (HR, 0.5; 95% CI, 0.31-0.86; P = .01), and the incidence rate was 2.4% vs 4.2% patients/year (log-rank P = .01). Conclusions: In a real-word study, NOACs use overcomes the indications provided by guidelines. This study evidenced that NOACs use in patients who developed AF after bioprosthetic AVR was more effective in prevention of thromboembolism and safe in reduction of major bleeding events compared with warfarin

    Mitogenomics reveals two cryptic species in Ciona intestinalis

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    Individual mitochondrial genes or genomic features are commonly used as phylogenetic markers at many taxonomic levels. We used a mitogenomics approach to demonstrate the existence of two cryptic species in the ascidian Ciona intestinalis, a model chordate whose status as a single species has recently been questioned. Comprehensive comparative analysis of the mitochondrial genome of the two cryptic species revealed significant differences in gene order, size and number of noncoding regions, compositional features and divergence of protein-coding genes

    Polyacetylenes Bearing Chiral-Substituted Fluorene and Terfluorene Pendant Groups: Synthesis and Properties

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    The synthesis of the first polyacetylenes bearing chiral fluorene-based pendant groups is described. Poly{9,9-bis[(S)-3,7-dimethyloctyl]fluoren-2-ylacetylene} (PFA1), poly{9,9-bis[(S)-2-methylbutyl]- fluoren-2-ylacetylene} (PFA2), and poly{9,9,9′,9′,9′′,9′′-hexakis[(S)-2-methylbutyl]-7,2′;7′,2′′-terfluoren- 2-ylacetylene} (PFA3) have been obtained by Rh(I)-catalyzed polymerization of the corresponding terminal acetylene monomers 2-ethynyl-9,9-bis[(S)-3,7-dimethyloctyl]fluorene (2a), 2-ethynyl-9,9-bis[(S)-2-methylbutyl]fluorene (2b), and 2-ethynyl-9,9,9′,9′,9′′,9′′-hexakis[(S)-2-methylbutyl]-7,2′;7′,2′′-terfluorene (10). The effect of the alkyl chain length at the C-9 position of fluorene on the structural and conformational aspects of the polymers PFA1 and PFA2 as well as on their chiroptical properties was studied by XRD, DSC, TGA, GPC, UV-vis, and CD. A more planar conformation of the polyenic backbone of PFA1 with respect to PFA2 can be inferred by a red shift of the ð-ð* transition in the UV-vis spectra. Their photoluminescence properties are those typical of fluorene systems. CD measurements evidenced Cotton effects of opposite signs in correspondence of the backbone absorption region, ascribable to an excess of a screw sense of the helical conformations assumed by the two polymers. PFA3 revealed an amorphous structure and exhibited peculiar thermal stability features (as indicated by TGA and DSC). Its emission spectra interest the violet-blue region and do not show any substantial red shift passing from solution to solid state, thus pointing out an aggregation prevention of terfluorene groups by means of the polyacetylene backbone

    approach to a water safety plan for recreational waters disinfection of a drainage pumping station as an unconventional point source of fecal contamination

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    Abstract In the context of the management of bathing water quality, the intermittent contamination of rainwater drainage pumps (unconventional point sources) could be controlled by peracetic acid disinfection. Thus, a field experimental study was carried out to set up a water safety plan, determining the monitoring parameters and the critical limit for corrective actions. With a 0.5 mg/l dosage, the average logarithmic microbial reduction was 0.50 ± 0.48 for Escherichia coli (EC) and 0.43 ± 0.54 for intestinal enterococci. Among the chemical and physical parameters that could be monitored in real time, the oxidation–reduction potential was the only one able to predict the microbial concentration discharged from a drainage pump and the logarithmic abatement of EC. Considering the possible impact of this source on bathing waters in terms of additional risk of gastrointestinal infections, the critical limit for continuous monitoring was established using a quantitative microbial risk assessment (QMRA) model
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