3,664 research outputs found
Perturbative unitarity bounds for effective composite models
In this paper we present the partial wave unitarity bound in the parameter
space of dimension-5 and dimension-6 effective operators that arise in a
compositeness scenario. These are routinely used in experimental searches at
the LHC to constraint contact and gauge interactions between ordinary Standard
Model fermions and excited (composite) states of mass . After deducing the
unitarity bound for the production process of a composite neutrino, we
implement such bound and compare it with the recent experimental exclusion
curves for Run 2, the High-Luminosity and High-Energy configurations of the
LHC. Our results also applies to the searches where a generic single excited
state is produced via contact interactions. We find that the unitarity bound,
so far overlooked, is quite complelling and significant portions of the
parameter space () become excluded in addition to the standard
request .Comment: This version of the paper merges the previous version published in
Phys. Lett. B 795 (2019) 644-649
(https://doi.org/10.1016/j.physletb.2019.06.042) with the subsequent Erratum
currently in press in Physics Letters B
(https://doi.org/10.1016/j.physletb.2019.134990
Hunting for heavy composite Majorana neutrinos at the LHC
We investigate the search for heavy Majorana neutrinos stemming from a
composite model scenario at the upcoming LHC Run II at a center of mass energy
of 13 TeV. While previous studies of the composite Majorana neutrino were
focussed on gauge interactions via magnetic type transition coupling between
ordinary and heavy fermions (with mass ) here we complement the composite
model with contact interactions at the energy scale and we find that
the production cross sections are dominated by such contact interactions by
roughly two/three orders of magnitude. This mechanism provides therefore very
interesting rates at the prospected luminosities. We study the same sign
di-lepton and di-jet signature () and perform a fast
detector simulation based on Delphes. We compute 3 and 5
contour plots of the statistical significance in the parameter space
(). We find that the potentially excluded regions at TeV are quite larger than those excluded so far at Run I considering
searches with other signatures.Comment: 14 pages, 9 figures, Minor comments and few references added. Version
accepted by the European Physical Journal C (EPJC
Advanced content-based semantic scene analysis and information retrieval: the SCHEMA project
The aim of the SCHEMA Network of Excellence is to bring together a critical mass of universities, research centers, industrial partners and end users, in order to design a reference system for content-based semantic scene analysis, interpretation and understanding. Relevant research areas include: content-based multimedia analysis and automatic annotation of semantic multimedia content, combined textual and multimedia information retrieval, semantic -web, MPEG-7 and MPEG-21 standards, user interfaces and human factors. In this paper, recent advances in content-based analysis, indexing and retrieval of digital media within the SCHEMA Network are presented. These advances will be integrated in the SCHEMA module-based, expandable reference system
Envy, Regret, and Social Welfare Loss
Incentive compatibility (IC) is a desirable property for any auction mechanism, including those used in online advertising. However, in real world applications practical constraints and complex environments often result in mechanisms that lack incentive compatibility. Recently, several papers investigated the problem of deploying black-box statistical tests to determine if an auction mechanism is incentive compatible by using the notion of IC-Regret that measures the regret of a truthful bidder. Unfortunately, most of those methods are computationally intensive, since they require the execution of many counterfactual experiments. In this work, we show that similar results can be obtained using the notion of IC-Envy. The advantage of IC-Envy is its efficiency: it can be computed using only the auction's outcome. In particular, we focus on position auctions. For position auctions, we show that for a large class of pricing schemes (which includes e.g. VCG and GSP), IC-Envy â„ IC-Regret (and IC-Envy = IC-Regret under mild supplementary conditions). Our theoretical results are completed showing that, in the position auction environment, IC-Envy can be used to bound the loss in social welfare due to the advertiser untruthful behavior. Finally, we show experimentally that IC-Envy can be used as a feature to predict IC-Regret in settings not covered by the theoretical results. In particular, using IC-Envy yields better results than training models using only price and value features
Conservation status of milkcaps (Basidiomycota, russulales, russulaceae), with notes on poorly known species
Mycological conservation has finally come of age. The increasingly recognized crucial role played by fungi in ecosystem functioning has spurred a wave of attention toward the status of fungal populations across the world. Milkcaps (Lactarius and Lactifluus) are a large and widespread group of ectomycorrhizal basidiomycetes; besides their ecological relevance, many species of milkcaps are of socio-economic significance because of their edibility. We analysed the presence of milkcaps in fungal Red Lists worldwide, ending up with an impressive list of 265 species assessed in various threat categories. Lactarius species are disproportionally red-listed with respect to Lactifluus (241 versus 24 species). Two species of Lactarius (L. maruiaensis and L. ogasawarashimensis) are currently considered extinct, and four more are regionally extinct; furthermore, 37 species are critically endangered at least in part of their distribution range. Several problems with the red-listing of milkcaps have been identified in this study, which overall originate from a poor understanding of the assessed species. Wrong or outdated nomenclature has been applied in many instances, and European names have been largely used to indicate taxa occurring in North America and Asia, sometimes without any supporting evidence. Moreover, several rarely recorded and poorly known species, for which virtually no data exist, have been included in Red Lists in some instances. We stress the importance of a detailed study of the species of milkcaps earmarked for insertion in Red Lists, either at national or international level, in order to avoid diminishing the value of this important conservation tool
CO2-Reduktion und Energieeffizienz im StraĂengĂŒterverkehr
The objective of our research was to analyse the relevant logistic factors influencing energy efficiency in road freight transport, while quantifying the potential for CO2 reduction. We carried out a survey and linked fuel consumption to transport performance parameters in 50 German haulage companies during 2003. Efficiency ranges from 0.8 tkm to 26 tkm for 1 kg CO2 emissions. The results show a high potential for improvements, given a low level of efficiency in vehicle usage and load
factor, scarce use of lightweight vehicle design, incorrectly selected vehicle class and a high proportion of empty runs. Efficiency measures are poorly applied
POTENTIAL BENEFITS OF COLOSTRUM IN GASTROINTESTINAL DISEASES
This paper reviews the composition of colostrum and the potebntial preventive and therapeutic use of this "first milk" for treating various gastrointestinal disorders in humans. Colostrum is a complex biological liquid that is rich in antimicrobial peptides, immune-regulanting compounds and growth factors than the subsequent mature milk. The main functions of colostrum are to provide essential nutritional components, strenghten the natural defense system, modulate immune response, balance intestinal microbiota and enhance the growth and repair of several tissues. several studies and clinical trials carried out both in vitro and in vivo on humans and animals suggest the clinical benefits of bovine colostrum (BC) supplementation in gastro-intestinal diseases. Despite the encouraging results, there are no contraindications regarding high dose levels and few side effects of clinical relevance have been reported. In conclusion, in the near future, colostrum-based supplementations may be play a role to synthetic drugs in the prevention and treatment of various gastrointestinal disorders
Technology and Sociomaterial Performation
Part 1: IS/IT Implementation and AppropriationInternational audienceOrganizational researchers have acknowledged that understanding the relationship between technology and organization is crucial to understanding modern organizing and organizational change [1]. There has been a significant amount of debate concerning the theoretical foundation of this relationship. Our research draws and extends Deleuze and DeLandaâs work on assemblages and Callonâs concept of performation to investigate how different sociomaterial practices are changed and stabilized after the implementation of new technology. Our findings from an in-depth study of two ambulatory clinics within a hospital system indicate that âperform-ingâ of constituting, counter-performing, calibrating, and stratifying explained the process of sociomaterial change and that this process is governed by an overarching principle of âperformative exigencyâ. Future studies on sociomateriality and change may benefit from a deeper understanding of how sociomaterial assemblages are rendered performative
How Equalization Techniques Affect the TCP Performance of MC-CDMA Systems in Correlated Fading Channels
This paper investigates the impact of several equalization techniques for multicarrier code division multiple access systems on the performance at both lower and upper layers (i.e., physical and TCP layers). Classical techniques such as maximal ratio combining, equal gain combining, orthogonality restoring combining, minimum mean square error, as well as a partial equalization (PE) are investigated in time- and frequency-correlated fading channels with various numbers of interferers. Their impact on the performance at upper level is then studied. The results are obtained through an integrated simulation platform carefully reproducing all main aspects affecting the quality of service perceived by the final user, allowing an investigation of the real gain produced by signal processing techniques at TCP level
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