933 research outputs found
Nash's bargaining problem and the scale-invariant Hirsch citation index
A number of citation indices have been proposed for measuring and ranking the
research publication records of scholars. Some of the best known indices, such
as those proposed by Hirsch and Woeginger, are designed to reward most highly
those records that strike some balance between productivity (number of papers
published), and impact (frequency with which those papers are cited). A large
number of rarely cited publications will not score well, nor will a very small
number of heavily cited papers. We discuss three new citation indices, one of
which was independently proposed in \cite{FHLB}. Each rests on the notion of
scale invariance, fundamental to John Nash's solution of the two-person
bargaining problem. Our main focus is on one of these -- a scale invariant
version of the Hirsch index. We argue that it has advantages over the original;
it produces fairer rankings within subdisciplines, is more decisive
(discriminates more finely, yielding fewer ties) and more dynamic (growing over
time via more frequent, smaller increments), and exhibits enhanced centrality
and tail balancedness. Simulations suggest that scale invariance improves
robustness under Poisson noise, with increased decisiveness having no cost in
terms of the number of ``accidental" reversals, wherein random irregularities
cause researcher A to receive a lower index value than B, although A's
productivity and impact are both slightly higher than B's. Moreover, we provide
an axiomatic characterization of the scale invariant Hirsch index, via axioms
that bear a close relationship, in discrete analogue, to those used by Nash in
\cite{Nas50}. This argues for the mathematical naturality of the new index.
An earlier version was presented at the 5th World Congress of the Game Theory
Society, Maastricht, Netherlands in 2016.Comment: 44 pages, 8 figure
10101 Abstracts Collection -- Computational Foundations of Social Choice
From March 7 to March 12, 2010, the Dagstuhl Seminar 10101
``Computational Foundations of Social Choice \u27\u27 was held in Schloss Dagstuhl~--~Leibniz Center for Informatics.
During the seminar, several participants presented their current
research, and ongoing work and open problems were discussed. Abstracts of
the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section
describes the seminar topics and goals in general.
Links to extended abstracts or full papers are provided, if available
10101 Executive Summary -- Computational Foundations of Social Choice
This seminar addressed some of the key issues in computational social choice, a novel interdisciplinary field of study at the interface of social choice theory and computer science. Computational social choice is concerned with the application of computational techniques to the study of social choice mechanisms, such as voting rules and fair division protocols, as well as with the integration of social choice paradigms into computing. The seminar brought together many of the most active researchers in the field and focussed the research community currently forming around these important and exciting topics
Depth of Field Analysis for Multilayer Automultiscopic Displays
With the re-emergence of stereoscopic displays, through polarized glasses for theatrical presentations and shuttered liquid crystal eyewear in the home, automultiscopic displays have received increased attention. Commercial efforts have predominantly focused on parallax barrier and lenticular architectures applied to LCD panels. Such designs suffer from reduced resolution and brightness. Recently, multilayer LCDs have emerged as an alternative supporting full-resolution imagery with enhanced brightness and depth of field. We present a signal-processing framework for comparing the depth of field for conventional automultiscopic displays and emerging architectures comprising multiple light-attenuating layers. We derive upper bounds for the depths of field, indicating the potential of multilayer configurations to significantly enhance resolution and depth of field, relative to conventional designs.Massachusetts Institute of Technology. Media LaboratoryMIT Camera Culture GroupNational Science Foundation (U.S.) (Grant IIS-1116452)United States. Defense Advanced Research Projects Agency. MOSAIC ProgramUnited States. Defense Advanced Research Projects Agency. SCENICC ProgramAlfred P. Sloan Foundation (Research Fellowship)United States. Defense Advanced Research Projects Agency. (Young Faculty Award
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Assessing the risk of venous thromboembolic events in women taking progestin-only contraception: a meta-analysis
Objectives: To evaluate the risk of venous thromboembolic events associated with the use of progestin-only contraception and whether that risk differs with the mode of drug delivery (oral, intrauterine, or depot injection). Design: Systematic review and meta-analysis of randomised controlled trials and observational studies. Data sources: Pubmed, Embase, Cochrane Library, and reference lists of relevant reviews. Study selection: Randomised controlled trials and case-control, cohort, and cross sectional studies with venous thromboembolic outcome for progestin-only contraception reported relative to a non-hormone comparator group. Data extraction: Data were extracted by two independent investigators, and consensus for inclusion was reached after assessment by additional investigators. Results: Among the 2022 unique references identified by all searches, eight observational studies fulfilled inclusion criteria. A total of 147 women across all studies were diagnosed with a venous thromboembolic event while taking progestin-only contraception, and the summary measure for the adjusted relative risk of a venous thromboembolic episode for users versus non-users of a progestin-only contraceptive was, based on the random effects model, 1.03 (95% CI 0.76 to 1.39). Subgroup analysis confirmed there was no association between venous thromboembolic risk and progestin-only pills (relative risk 0.90 (0.57 to 1.45)) or a progestin intrauterine device (0.61 (0.24 to 1.53)). The relative risk of a venous thromboembolic event for users of an injectable progestin versus non-users was 2.67 (1.29 to 5.53). Conclusions: Published data assessing the risk of venous thromboembolism in women prescribed progestin-only contraception are limited. In this meta-analysis of eight observational studies, the use of progestin-only contraception was not associated with an increased risk of venous thromboembolism compared with non-users of hormonal contraception. The potential association between injectable progestins and thrombosis requires further study
Almost Envy-Free Allocations with Connected Bundles
We study the existence of allocations of indivisible goods that are envy-free up to one good (EF1), under the additional constraint that each bundle needs to be connected in an underlying item graph G. When the items are arranged in a path, we show that EF1 allocations are guaranteed to exist for arbitrary monotonic utility functions over bundles, provided that either there are at most four agents, or there are any number of agents but they all have identical utility functions. Our existence proofs are based on classical arguments from the divisible cake-cutting setting, and involve discrete analogues of cut-and-choose, of Stromquist\u27s moving-knife protocol, and of the Su-Simmons argument based on Sperner\u27s lemma. Sperner\u27s lemma can also be used to show that on a path, an EF2 allocation exists for any number of agents. Except for the results using Sperner\u27s lemma, all of our procedures can be implemented by efficient algorithms. Our positive results for paths imply the existence of connected EF1 or EF2 allocations whenever G is traceable, i.e., contains a Hamiltonian path. For the case of two agents, we completely characterize the class of graphs G that guarantee the existence of EF1 allocations as the class of graphs whose biconnected components are arranged in a path. This class is strictly larger than the class of traceable graphs; one can check in linear time whether a graph belongs to this class, and if so return an EF1 allocation
Th17 micro-milieu regulates NLRP1-dependent caspase-5 activity in skin autoinflammation.
IL-1β is a potent player in cutaneous inflammation and central for the development of a Th17 micro-milieu in autoinflammatory diseases including psoriasis. Its production is controlled at the transcriptional level and by subsequent posttranslational processing via inflammatory caspases. In this study, we detected inflammatory caspase-5 active in epidermal keratinocytes and in psoriatic skin lesions. Further, interferon-γ and interleukin-17A synergistically induced caspase-5 expression in cultured keratinocytes, which was dependent on the antimicrobial peptide psoriasin (S100A7). However, diseases-relevant triggers for caspase-5 activity and IL-1β production remain unknown. Recently, extranuclear DNA has been identified as danger-signals abundant in the psoriatic epidermis. Here, we could demonstrate that cytosolic double-stranded (ds) DNA transfected into keratinocytes triggered the activation of caspase-5 and the release of IL-1β. Further, interleukin-17A promoted caspase-5 function via facilitation of the NLRP1-inflammasome. Anti-inflammatory vitamin D interfered with the IL-1β release and suppressed caspase-5 in keratinocytes and in psoriatic skin lesions. Our data link the disease-intrinsic danger signals psoriasin (S100A7) and dsDNA for NLPR1-dependent caspase-5 activity in psoriasis providing potential therapeutic targets in Th17-mediated skin autoinflammation
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