9,824 research outputs found
Finding large stable matchings
When ties and incomplete preference lists are permitted in the stable marriage and hospitals/residents problems, stable matchings can have different sizes. The problem of finding a maximum cardinality stable matching in this context is known to be NP-hard, even under very severe restrictions on the number, size, and position of ties. In this article, we present two new heuristics for finding large stable matchings in variants of these problems in which ties are on one side only. We describe an empirical study involving these heuristics and the best existing approximation algorithm for this problem. Our results indicate that all three of these algorithms perform significantly better than naive tie-breaking algorithms when applied to real-world and randomly-generated data sets and that one of the new heuristics fares slightly better than the other algorithms, in most cases. This study, and these particular problem variants, are motivated by important applications in large-scale centralized matching schemes
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The assessment of the implementation of fuel related legislations and their impact on air quality and public health
The main focus of Work Package 6 of the Aphekom project was: to develop innovative methods to analyse the decrease in air pollution levels following implementation of an European regulation to reduce the sulphur content in liquid fuels; to follow the evolution of health risks over time; to track related effect modifiers; and to quantify the monetary costs of health impacts of the implemented regulation
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Profiling SO2 air pollution patterns in 9 EU Aphekom cities: The Aphekom Project
A detailed analysis of hourly pollutant concentrations mainly focusing on SO2 data obtained from 9 centres involved in the Aphekom project was conducted. This involved the generation of individual diurnal SO2 profiles in order to:
(i) identify city specific patterns including source apportionment and quantification,
(ii) track changes over time,
(iii) analyse the changes in SO2 concentrations from different emission sources, i.e. traffic, heating, shipping and industrial sources, overtime
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Mortality impacts of sulphur concetrations in 20 European cities in the APHEKOM Project
The implementation of three EU directives to reduce sulphur content in fuel was assessed for mortality impacts
in 20 European cities, between 1990 and 2007 in the APHEKOM project. This specific study aimed to examine whether different lag structures apply to the relationships between cardiovascular and respiratory events and SO2 concentrations, which will therefore result in differences in mortality impacts from regulation implementation. Prior evidence has shown that cardiovascular mortality is more likely to be affected by SO2 concentrations on the same or the previous day of the event, while respiratory mortality more likely to show a delayed effect of exposure to the same pollutant
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The APHEKOM Project: A literature review of air pollution interventions and their impact of public health
Intervention studies play an important role in supporting and complementing scientific validation of results of epidemiological non-intervention studies linking air pollution and health. In this paper a collection of existing published intervention studies is reviewed with the aim to give a summarized overview spanning a variety of approaches regarding the type of the intervention and findings with the main focus on studies that assessed interventions that improved air quality and the associated positive impact on public health. Air pollution interventions were defined as events aimed at reducing air pollution and also events where air pollution reductions occurred as a side effect
Rice endosperm is cost-effective for the production of recombinant griffithsin with potent activity against HIV
Protein microbicides containing neutralizing antibodies and antiviral lectins may help to reduce the rate of infection with human immunodeficiency virus (HIV) if it is possible to manufacture the components in large quantities at a cost affordable in HIV‐endemic regions such as sub‐Saharan Africa. We expressed the antiviral lectin griffithsin (GRFT), which shows potent neutralizing activity against HIV, in the endosperm of transgenic rice plants (Oryza sativa), to determine whether rice can be used to produce inexpensive GRFT as a microbicide ingredient. The yield of (OS)GRFT in the best‐performing plants was 223 μg/g dry seed weight. We also established a one‐step purification protocol, achieving a recovery of 74% and a purity of 80%, which potentially could be developed into a larger‐scale process to facilitate inexpensive downstream processing. (OS)GRFT bound to HIV glycans with similar efficiency to GRFT produced in Escherichia coli. Whole‐cell assays using purified (OS)GRFT and infectivity assays using crude extracts of transgenic rice endosperm confirmed that both crude and pure (OS)GRFT showed potent activity against HIV and the crude extracts were not toxic towards human cell lines, suggesting they could be administered as a microbicide with only minimal processing. A freedom‐to‐operate analysis confirmed that GRFT produced in rice is suitable for commercial development, and an economic evaluation suggested that 1.8 kg/ha of pure GRFT could be produced from rice seeds. Our data therefore indicate that rice could be developed as an inexpensive production platform for GRFT as a microbicide component
Regression of murine lung tumors by the let-7 microRNA.
MicroRNAs (miRNAs) have recently emerged as an important new class of cellular regulators that control various cellular processes and are implicated in human diseases, including cancer. Here, we show that loss of let-7 function enhances lung tumor formation in vivo, strongly supporting the hypothesis that let-7 is a tumor suppressor. Moreover, we report that exogenous delivery of let-7 to established tumors in mouse models of non-small-cell lung cancer (NSCLC) significantly reduces the tumor burden. These results demonstrate the therapeutic potential of let-7 in NSCLC and point to miRNA replacement therapy as a promising approach in cancer treatment
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