2,677 research outputs found
A robust SNP barcode for typing Mycobacterium tuberculosis complex strains
Strain-specific genomic diversity in the Mycobacterium tuberculosis complex (MTBC) is an important factor in pathogenesis that may affect virulence, transmissibility, host response and emergence of drug resistance. Several systems have been proposed to classify MTBC strains into distinct lineages and families. Here, we investigate single-nucleotide polymorphisms (SNPs) as robust (stable) markers of genetic variation for phylogenetic analysis. We identify ~92k SNP across a global collection of 1,601 genomes. The SNP-based phylogeny is consistent with the gold-standard regions of difference (RD) classification system. Of the ~7k strain-specific SNPs identified, 62 markers are proposed to discriminate known circulating strains. This SNP-based barcode is the first to cover all main lineages, and classifies a greater number of sublineages than current alternatives. It may be used to classify clinical isolates to evaluate tools to control the disease, including therapeutics and vaccines whose effectiveness may vary by strain type
End-to-End V2X Latency Modeling and Analysis in 5G Networks
networks provide higher flexibility and improved performance compared to previous cellular technologies. This has raised expectations on the possibility to support advanced Vehicle to Everything (V2X) services using the cellular network via Vehicle-to-Network (V2N) and Vehicle-to-Network-to-Vehicle (V2N2V) connections. The possibility to support critical V2X services using 5G V2N2V or V2N connections depends on their end-to-end (E2E) latency. The E2E latency of V2N2V or V2N connections depends on the particular 5G network deployment, dimensioning and configuration, in addition to the network load. To date, few studies have analyzed the capabilities of V2N2V or V2N connections to support critical V2X services, and most of them focus on the 5G radio access network or consider dedicated 5G pilot deployments under controlled conditions. This paper progresses the state-of-the-art by introducing a novel E2E latency model to quantify the latency of 5G V2N and V2N2V communications. The model includes the latency introduced at the radio, transport, core, Internet, peering points and application server (AS) when vehicles are supported by a single mobile network operator (MNO) and when they are supported by multiple MNOs. The model can quantify the latency experienced when the V2X AS is deployed from the edge of the network (using MEC platforms) to the cloud. Using this model, this study estimates the E2E latency of 5G V2N2V connections for a large variety of possible 5G network deployments and configurations. The analysis helps identify which 5G network deployments and configurations are more suitable to meet V2X latency requirements. To this aim, we consider as case study the cooperative lane change service. The conducted analysis highlights the challenge for centralized network deployments that locate the V2X AS at the cloud to meet the latency requirements of advanced V2X services. Locating the V2X AS closer to the cell edge reduces the latency. However, it requires a higher number of ASs and also a careful dimensioning of the network and its configuration to ensure sufficient network and AS resources are dedicated to serve the V2X traffic
Cohomology and Deformation of Leibniz Pairs
Cohomology and deformation theories are developed for Poisson algebras
starting with the more general concept of a Leibniz pair, namely of an
associative algebra together with a Lie algebra mapped into the
derivations of . A bicomplex (with both Hochschild and Chevalley-Eilenberg
cohomologies) is essential.Comment: 15 page
Phytochemical Profile of Opuntia ficus-indica (L.) Mill Fruits (cv. ‘Orito’) Stored at Different Conditions
This research analyzed the phytochemical profile of prickly pear fruits from ‘Orito’ cultivar stored under cold conditions (2◦ C, 85–90% RH) and shelf-life conditions at room temperature (stored at 20◦ C for three days after cold storage) for 28 days, mimicking the product life cycle. A total of 18 compounds were identified and quantitated through HPLC-DAD-MS/MS (High-Performance Liquid Chromatographic-Diode Array Detector-Mass Spectrometry) analyses. Phenolic acids such as eucomic acid and betalains such as indicaxanthin were the predominant chemical families, and piscidic acid was the most abundant compound. During cold storage, the content of eucomic acid isomer/derivative and syringaresinol increased, and citric acid decreased, which could be caused by the cold activation of the phenylalanine ammonia-lyase (PAL) and polyphenol oxidase (PPO) enzymes. However, no significant differences were found in the content of these compounds during shelf-life storage. These results showed that ‘Orito’ fruit marketability would be possible up to 28 days after harvesting, retaining its profile, which is rich in bioactive compounds
To dash or to dawdle: verb-associated speed of motion influences eye movements during spoken sentence comprehension
In describing motion events verbs of manner provide information about the speed of agents or objects in those events. We used eye tracking to investigate how inferences about this verb-associated speed of motion would influence the time course of attention to a visual scene that matched an event described in language. Eye movements were recorded as participants heard spoken sentences with verbs that implied a fast (“dash”) or slow (“dawdle”) movement of an agent towards a goal. These sentences were heard whilst participants concurrently looked at scenes depicting the agent and a path which led to the goal object. Our results indicate a mapping of events onto the visual scene consistent with participants mentally simulating the movement of the agent along the path towards the goal: when the verb implies a slow manner of motion, participants look more often and longer along the path to the goal; when the verb implies a fast manner of motion, participants tend to look earlier at the goal and less on the path. These results reveal that event comprehension in the presence of a visual world involves establishing and dynamically updating the locations of entities in response to linguistic descriptions of events
Fermionic R-Operator and Algebraic Structure of 1D Hubbard Model: Its application to quantum transfer matrix
The algebraic structure of the 1D Hubbard model is studied by means of the
fermionic R-operator approach. This approach treats the fermion models directly
in the framework of the quantum inverse scattering method. Compared with the
graded approach, this approach has several advantages. First, the global
properties of the Hamiltonian are naturally reflected in the algebraic
properties of the fermionic R-operator. We want to note that this operator is a
local operator acting on fermion Fock spaces. In particular, SO(4) symmetry and
the invariance under the partial particle hole transformation are discussed.
Second, we can construct a genuinely fermionic quantum transfer transfer matrix
(QTM) in terms of the fermionic R-operator. Using the algebraic Bethe Ansatz
for the Hubbard model, we diagonalize the fermionic QTM and discuss its
properties.Comment: 22 pages, no figure
Aspects of Two-Photon Physics at Linear e+e- Colliders
We discuss various reactions at future e+e- and gamma-gamma colliders
involving real (beamstrahlung or backscattered laser) or quasi--real
(bremsstrahlung) photons in the initial state and hadrons in the final state.
The production of two central jets with large pT is described in some detail;
we give distributions for the rapidity and pT of the jets as well as the
di--jet invariant mass, and discuss the relative importance of various initial
state configurations and the uncertainties in our predictions. We also present
results for `mono--jet' production where one jet goes down a beam pipe, for the
production of charm, bottom and top quarks, and for single production of W and
Z bosons. Where appropriate, the two--photon processes are compared with
annihilation reactions leading to similar final states. We also argue that the
behaviour of the total inelastic gamma-gamma cross section at high energies
will probably have little impact on the severity of background problems caused
by soft and semi--hard (`minijet') two--photon reactions. We find very large
differences in cross sections for all two--photon processes between existing
designs for future e+e- colliders, due to the different beamstrahlung spectra;
in particular, both designs with >1 events per bunch crossing exist.Comment: 51 pages, 13 figures(not included
On the Papapetrou field in vacuum
In this paper we study the electromagnetic fields generated by a Killing
vector field in vacuum space-times (Papapetrou fields). The motivation of this
work is to provide new tools for the resolution of Maxwell's equations as well
as for the search, characterization, and study of exact solutions of Einstein's
equations. The first part of this paper is devoted to an algebraic study in
which we give an explicit and covariant procedure to construct the principal
null directions of a Papapetrou field. In the second part, we focus on the main
differential properties of the principal directions, studying when they are
geodesic, and in that case we compute their associated optical scalars. With
this information we get the conditions that a principal direction of the
Papapetrou field must satisfy in order to be aligned with a multiple principal
direction of the Weyl tensor in the case of algebraically special vacuum
space-times. Finally, we illustrate this study using the Kerr, Kasner and pp
waves space-times.Comment: 24 pages, LaTeX2e, IOP style. To appear in Classical and Quantum
Gravit
-- mixing and oblique corrections in an model
A global fit for experiments is included in this revised version.Comment: IFP-460-UNC, TRI-PP-93-11, 20 pages, 2 figures are appende
An analysis of innovation in textile companies: an efficiency approach
[EN] The elimination of trade contingency measures in 2005 triggered a process of renewal in the textile sector, requiring major investments. The divide between efficiency and innovation has become an issue of major importance for decision-making in the Spanish textile sector. This study provides quantitative data on the efficiency levels of innovative Spanish textile companies. The aim is to identify their distinguishing features and establish a possible pattern to follow. In addition, truncated regression is used to estimate the determinants of efficiency, in order to check the significance of innovation processes for firms.Puertas Medina, RM.; Martí Selva, ML.; Calafat Marzal, MC. (2020). An analysis of innovation in textile companies: an efficiency approach. Bulletin of Economic Research (Online). 72(1):63-76. https://doi.org/10.1111/boer.12210S6376721Banker, R. D., Charnes, A., & Cooper, W. W. (1984). Some Models for Estimating Technical and Scale Inefficiencies in Data Envelopment Analysis. Management Science, 30(9), 1078-1092. doi:10.1287/mnsc.30.9.1078Bastos F. &Nasir J.(2004).Productivity and the investment climate: What matters most?World Bank Policy Research Working Paper3335.Becker, S. O., & Egger, P. H. (2009). Endogenous product versus process innovation and a firm’s propensity to export. Empirical Economics, 44(1), 329-354. doi:10.1007/s00181-009-0322-6Beneito, P., Coscollá-Girona, P., Rochina-Barrachina, M. E., & Sanchis, A. (2015). Competitive Pressure and Innovation at the Firm Level. The Journal of Industrial Economics, 63(3), 422-457. doi:10.1111/joie.12079Bhandari, A. K., & Ray, S. C. (2011). TECHNICAL EFFICIENCY IN THE INDIAN TEXTILES INDUSTRY: A NON-PARAMETRIC ANALYSIS OF FIRM-LEVEL DATA. Bulletin of Economic Research, 64(1), 109-124. doi:10.1111/j.1467-8586.2010.00381.xCassiman, B., Golovko, E., & Martínez-Ros, E. (2010). Innovation, exports and productivity. International Journal of Industrial Organization, 28(4), 372-376. doi:10.1016/j.ijindorg.2010.03.005Crépon B. Duguet E. &Mairesse J.(1998).Research innovation and productivity an econometric analysis at the firm level. NBER Working Paper 6696.https://doi.org/10.1080/10438599800000031De Jorge-Moreno, J., & Rojas Carrasco, O. (2015). Technical efficiency and its determinants factors in Spanish textiles industry (2002-2009). Journal of Economic Studies, 42(3), 346-357. doi:10.1108/jes-06-2013-0085Diaz-Balteiro, L., Casimiro Herruzo, A., Martinez, M., & González-Pachón, J. (2006). An analysis of productive efficiency and innovation activity using DEA: An application to Spain’s wood-based industry. Forest Policy and Economics, 8(7), 762-773. doi:10.1016/j.forpol.2005.06.004Duch N.(2006).Posición competitiva y estrategias de las empresas catalanas. Análisis del Programa Créixer (2003–2005). Documents de treball. CIDEM. Generalitat de Catalunya.Goedhuys, M., & Veugelers, R. (2012). Innovation strategies, process and product innovations and growth: Firm-level evidence from Brazil. Structural Change and Economic Dynamics, 23(4), 516-529. doi:10.1016/j.strueco.2011.01.004Harrison, R., Jaumandreu, J., Mairesse, J., & Peters, B. (2014). Does innovation stimulate employment? A firm-level analysis using comparable micro-data from four European countries. International Journal of Industrial Organization, 35, 29-43. doi:10.1016/j.ijindorg.2014.06.001Huergo, E., & Jaumandreu, J. (2004). Firms’ age, process innovation and productivity growth. International Journal of Industrial Organization, 22(4), 541-559. doi:10.1016/j.ijindorg.2003.12.002Kouliavtsev, M., Christoffersen, S., & Russel, P. (2006). Productivity, Scale and Efficiency in the U.S. Textile Industry. Empirical Economics, 32(1), 1-18. doi:10.1007/s00181-006-0069-2Sanchez R. &Diaz A.(2013).Are large innovative firms more efficient?MRPA Paper n° 44592.Sellers R. Nicolau J. L. &Mas F. J.(2002).Eficiencia en la distribución: Una aplicación en el sector de agencias de viaje. Working paper serie ED N°17. Instituto Valenciano de Investigaciones Económicas. Retrieved fromhttp://hdl.handle.net/10045/23320Zheng J. Liu X. &Bigsten A.(2000).Efficiency Technical Progress and Best Practice in Chinese State Enterprises (1980–1994). Working Papers in Economics n 30 Department of Economics. Göteborg.https://doi.org/10.1016/S0147-5967(02)00010-
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