3,979 research outputs found

    Normalizing Weak Boson Pair Production at the Large Hadron Collider

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    The production of two weak bosons at the Large Hadron Collider will be one of the most important sources of SM backgrounds for final states with multiple leptons. In this paper we consider several quantities that can help normalize the production of weak boson pairs. Ratios of inclusive cross-sections for production of two weak bosons and Drell-Yan are investigated and the corresponding theoretical errors are evaluated. The possibility of predicting the jet veto survival probability of VV production from Drell-Yan data is also considered. Overall, the theoretical errors on all quantities remain less than 5-20%. The dependence of these quantities on the center of mass energy of the proton-proton collision is also studied.Comment: 11 pages; added references, minor text revisions, version to appear in Phys. Rev.

    Investigation of latent heat effects at the stratocumulus top using direct numerical simulations

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    Prevalence of Bartonella henselae in blood donors and risk of blood transmission in Chile

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    Indexación: Scopus; Scielo.Bartonella henselae es el agente causal de la enfermedad del arañazo del gato en personas inmunocompetentes y de la angiomatosis bacilar y peliosis hepatis en inmunocomprometidos. En Chile la prevalencia de anticuerpos contra B. henselae en niños y adolescentes sanos es de 13,3%, en personas con riesgo ocupacional 60,5% y en gatos 85,6%. No existen datos publicados respecto de la seroprevalencia en donantes de sangre en nuestro país, por lo que determinar si B. henselae se encuentra presente en la sangre de los donantes al momento de la donación es muy importante, ya que este microorganismo puede sobrevivir hasta 35 días en los eritrocitos almacenados en banco de sangre a 4 °C. Objetivo: Determinar la prevalencia de B. henselae en donantes de sangre. Metodología: Se analizaron 140 muestras de sangre de donantes, para detectar la presencia de B. henselae, utilizando la técnica de la reacción de polimerasa en cadena (RPC). Resultados: Se obtuvo 13,6% de los donantes de sangre con RPC positiva para la B. henselae. La secuencia de los fragmentos amplificados presentó una identidad por sobre 98% con respecto a secuencias de B. henselae de referencia. Conclusión: El riesgo de transmisión sanguínea debiera ser considerado en un país con alta seroprevalencia de infección por B. henselae.Bartonella henselae is the causal agent of cat scratch disease in immunocompetent persons and bacterial angiomatosis in immunocompromised patients. In Chile, the prevalence of antibodies against B. henselae in healthy children and adolescents is 13.3%, in persons with occupational risk 60.5%, and in cats 85.6%. There are no published data regarding the seroprevalence in blood donors in our country, so determining if B. henselae is present in the blood of donors at the time of donation is very important, since this microorganism can survive up to 35 days in the red blood cells stored in a blood bank at 4 °C. Objective: To determine the prevalence of B. henselae in blood donors. Methodology: 140 donor blood samples were analyzed to detect the presence of B. henselae, using the polymerase chain reaction technique. Results: 13.6% of the blood donors with positive polymerase chain reaction for B. henselae were obtained. The sequence of the amplified fragments showed an identity of over 98% with respect to B. henselae reference sequences. Conclusion: The risk of blood transmission is due to a country with high B. henselae infection.https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0716-10182017000600539&lng=en&nrm=iso&tlng=e

    Valoración del cambio tecnológico. Renta visible o invisible en las sociedades de regantes a los efectos de la valoración según la nueva ley del suelo (ls 2/2008) en España

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    In this study, a new valuation model is proposed for undergroundwater extraction for irrigation, within the framework of thenew Land Law (Ley del Suelo) in Spain. For this purpose, amethod for rent capitalization, real or potential, is appliedunder different possible scenarios in irrigator communitiesin the province of Valencia, depending on the procedure forprice fixing of water sold to members and the adoption of newlocalized irrigation technologies. In practice, water prices areequivalent to unit costs, which is why the actual rent of theexploitation is made invisible, and to make it visible, a waterprice must be considered. Consideration of the potential rentversus the real rent does not influence the value of societies thatuse new irrigation technologies, contrary to what happens inexploitations with traditional irrigation systems, which elevatetheir value.En el presente trabajo se formula un modelo de valoración delas explotaciones de agua subterránea para riego, en el marco dela nueva Ley del Suelo en España. Para ello se aplica el métodode capitalización de la renta, real o potencial, bajo distintos escenariosposibles de las comunidades de regantes de la provinciade Valencia, según sea el procedimiento de fijación del preciode venta del agua a los socios y la adopción de las nuevas tecnologíasde riego localizado. En la práctica, los precios del aguase hacen equivalentes a los costos unitarios, por lo que la rentareal de la explotación se hace invisible, y para hacerla visiblese debe considerar un precio del agua. La consideración de larenta potencial frente a la renta real no influye en el valor de lassociedades que utilizan nuevas tecnologías de riego, al contrariode lo que ocurre en las explotaciones con sistemas de riego tradicionales,que hace elevar su valor

    Characterization of the Basic Replicon of pCM1, a Narrow- Host-Range Plasmid from the Moderate Halophile Chromohalobacter marismortui

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    The moderately halophilic bacterium Chromohalobacter marismortui contains a 17.5-kb narrow-host-range plasmid, pCM1, which shows interesting properties for the development of cloning vectors for the genetic manipulation of this important group of extremophiles. Plasmid pCM1 can stably replicate and is maintained in most gram-negative moderate halophiles tested. The replication origin has been identified and sequenced, and the minimal pCM1 replicon has been localized to a 1,600-bp region which includes two functionally discrete regions, the oriV region and the repA gene. oriV, located on a 700-bp fragment, contains four iterons 20 bp in length adjacent to a DnaA box that is dispensable but required for efficient replication of pCM1, and it requires trans-acting functions. The repA gene, which encodes a replication protein of 289 residues, is similar to the replication proteins of other gram-negative bacteria

    Maintaining security requirements of software systems using evolving crosscutting dependencies

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    Security requirements are concerned with protecting assets of a system from harm. Implemented as code aspects to weave protection mechanisms into the system, security requirements need to be validated when changes are made to the programs during system evolution. However, it was not clear for developers whether existing validation procedures such as test cases are sufficient for security and when the implemented aspects need to adapt. In this chapter, we propose an approach for detecting any change to the satisfaction of security requirements in three steps: (1) identify the asset variables in the systems that are only accessed by a join-point method; (2) trace these asset variables to identify both control and data dependencies between the non-aspect and aspect functions; and (3) update the test cases ac-cording to implementation of these dependencies to strengthen the protection when a change happens. These steps are illustrated by a case study of a meeting scheduling system where security is a critical concern

    Rapid discrimination and classification of edible insect powders using ATR-FTIR spectroscopy combined with multivariate analysis

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    Insects are being proposed as an alternative way to ensure world''s food and feed security. Methods to determine edible insect powder''s origin and species will be needed for quality control purposes. Infrared spectroscopy has been extensively used in rapid chemical fingerprinting of food products. The present research explores a new approach to discriminate and classify commercial edible insect powders using attenuated total reflectance mid-infrared spectroscopy combined with multivariate analysis. Infrared spectra of seven commercial edible insect powders from different species (Tenebrio molitor, Alphitobius diaperinus, Gryllodes sigillatus, Acheta domesticus and Locusta migratoria) and origins (the Netherlands and New Zealand) were collected to build up soft independent modelling of class analogy (SIMCA) models. SIMCA models clearly discriminated insects by their species and origin linking their differences to lipids and chitin. SIMCA models performance was tested using five spectra of each class not used to build up the training set. 100% correct predictions were obtained for all the samples analysed with the exception of one sample of Alphitobius diaperinus. Infrared spectroscopy coupled to multivariate analysis provided a powerful method for the assurance of insect powder''s authenticity

    Architectures for Future Media Internet

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    Among the major reasons for the success of the Internet have been the simple networking architecture and the IP interoperation layer. However, the traffic model has recently changed. More and more applications (e.g. peerto-peer, content delivery networks) target on the content that they deliver rather than on the addresses of the servers who (originally) published/hosted that content. This trend has motivated a number of content-oriented networking studies. In this paper we summarize some the most important approache

    Secure Geographic Routing in Ad Hoc and Wireless Sensor Networks

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    Security in sensor networks is one of the most relevant research topics in resource constrained wireless devices and networks. Several attacks can be suffered in ad hoc and wireless sensor networks (WSN), which are highly susceptible to attacks, due to the limited resources of the nodes. In this paper, we propose innovative and lightweight localization techniques that allow for intrusion identification and isolation schemes and provide accurate location information. This information is used by our routing protocol which additionally incorporates a distributed trust model to prevent several routing attacks to the network. We finally evaluate our algorithms for accurate localization and for secure routing which have been implemented and tested in real ad hoc and wireless sensor networks
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