3,548 research outputs found
Top mass dependent alpha_s^3 corrections to B-meson mixing in the MSSM
We compute the top mass dependent NLO strong interaction matching conditions
to the Delta F=2 effective Hamiltonian in the general MSSM. We study the
relevance of such corrections, comparing its size with that of previously known
NLO corrections in the limit mt->0, in scenarios with degeneracy, alignment,
and hierarchical squarks. We find that, while these corrections are generally
small, there are regions in the parameter space where the contributions to the
Wilson coefficients C1 and C4 could partially overcome the expected suppression
m_t/M_SUSY.Comment: 15 pages, 6 figure
Identification by means of molecular tools of the microbiota responsible for the formation of histamine accumulated in commercial cheeses in Spain
Histamine intoxication is an important food safety and public health concern. Ripened cheeses are the most common dairy products in which histamine can accumulate. Histamine is formed by the microbiota present in cheese by decarboxylation of histidine, due to the action of the histidine decarboxylase. This study's objective was to identify the responsible for the formation of histamine accumulated in commercial cheeses. The content of histamine of 39 different types of cheeses marketed in Spain, of varying milk origin, was assessed. About one third of the cheeses analysed contained more than 200 mg/kg histamine; two cheeses exceeded 500 mg/kg histamine, the consumption of such cheeses can be harmful or even toxic for consumers. The five cheeses with the highest histamine concentrations were selected for in-depth molecular analysis. Firstly, bacterial and yeast isolates were obtained, and then the total genetic material from the cheeses was analysed, in order to verify the putative presence of the hdc histidine decarboxylase gene. In order to identify the histamine producing microorganisms, the nucleotide sequences of the histidine decarboxylase genes from the cheeses were amplified, and subjected them to Sanger sequencing. In four of the five selected cheeses, the main histamine producer was identified as Lentilactobacillus parabuchneri, whereas in the remaining cheese it was Tetragenococcus halophilus. The hdc gene was located in an unstable plasmid, only present in that cheese sample. Since all histamine producing microorganisms identified in this study are not part of the species used in cheese starter cultures, an improvement of hygienic manufacturing practices and/or thermal treatments for microbial inactivation in milk may be considered to prevent histamine accumulation in cheeses during ripening
Potential of histamine-degrading microorganisms and diamine oxidase (DAO) for the reduction of histamine accumulation along the cheese ripening process
Lentilactobacillus parabuchneri is the main bacteria responsible for the accumulation of histamine in cheese. The goal of this study was to assess the efficiency of potential histamine-degrading microbial strains or, alternatively, the action of the diamine oxidase (DAO) enzyme in the reduction of histamine accumulation along the ripening process in cheese. A total of 8 cheese variants of cow milk cheese were manufactured, all of them containing L. parabuchneri Deutsche Sammlung von Mikroorganismen 5987 (except for the negative control cheese variant) along with histamineâdegrading strains (Lacticaseibacillus casei 4a and 18b; Lactobacillus delbrueckii subsp. bulgaricus ColecciĂłn EspaĂąola de Cultivos Tipo (CECT) 4005 and Streptococcus salivarius subsp. thermophilus CECT 7207; two commercial yogurt starter cultures; or Debaryomyces hansenii), or DAO enzyme, tested in each cheese variant. Histamine was quantified along 100 days of cheese ripening. All the degrading measures tested significantly reduced the concentration of histamine. The highest degree of degradation was observed in the cheese variant containing D. hansenii, where the histamine content decreased up to 45.32 %. Cheese variants with L. casei, or L. bulgaricus and S. thermophilus strains, also decreased in terms of histamine content by 43.05 % and 42.31 %, respectively. No significant physicochemical changes (weight, pH, water activity, color, or texture) were observed as a consequence of the addition of potential histamine-degrading adjunct cultures or DAO in cheeses. However, the addition of histamine-degrading microorganisms was associated with a particular, not unpleasant aroma. Altogether, these results suggest that the use of certain histamine-degrading microorganisms could be proposed as a suitable measure in order to decrease the amount of histamine accumulated in cheeses. Š 2022 The Author
The significance of cheese sampling in the determination of histamine concentration: Distribution pattern of histamine in ripened cheeses
Cheeses are becoming a major safety and public health concern: cheeses available in supermarkets occasionally contain high histamine concentrations that can have negative effects on consumer health. In this study, we have attempted to assess the histamine distribution pattern in ripened cheeses, with the purpose of establishing a correct cheese sampling strategy for the quantification of histamine. To this aim, histamine was determined in four distinct areas of twelve long-ripened hard cheeses: the external and internal rind, along with the outer and inner core of the wedge. The concentrations measured were remarkably different: histamine accumulated in the central core, whereas the lowest amount was found in the peripheral rind. To explain this heterogenous distribution, histamine producers were determined in the four areas by identifying the hdc sequences obtained from cheese samples. Non-starter bacteria were identified as main histamine producers; however, these microbiota were homogeneously distributed throughout the wedge. Nevertheless, the analysis of psychochemical properties of the different areas revealed an observable trend: histamine tended to accumulate in the saltier, more humid, and less oxidized areas in a wedge. Overall, this study highlights the significance of a correct sampling strategy when histamine is quantified in cheese
Complete Anatomy of B -> K*ll and its angular distribution
We present a complete and optimal set of observables for the exclusive 4-body
B meson decay B -> K*(->K pi) l+l- in the low dilepton mass region, that
contains a maximal number of clean observables. This basis of observables is
built in a systematic way. We show that all the previously defined observables
and any observable that one can construct, can be expressed as a function of
this basis. This set of observables contains all the information that can be
extracted from the angular distribution in the cleanest possible way. We
provide explicit expressions for the full and the uniangular distributions in
terms of this basis. The conclusions presented here can be easily extended to
the large-q^2 region. We study the sensitivity of the observables to
right-handed currents and scalars. Finally, we present for the first time all
the symmetries of the full distribution including massive terms and scalar
contributions.Comment: 37 pages, 12 Figures. Corrected typo in Eqs. (29) and (44). Results
and conclusions unchange
Implications from clean observables for the binned analysis of B -> K*ll at large recoil
We perform a frequentist analysis of q^2-dependent B-> K*(->Kpi)ll angular
observables at large recoil, aiming at bridging the gap between current
theoretical analyses and the actual experimental measurements. We focus on the
most appropriate set of observables to measure and on the role of the
q^2-binning. We highlight the importance of the observables P_i exhibiting a
limited sensitivity to soft form factors for the search for New Physics
contributions. We compute predictions for these binned observables in the
Standard Model, and we compare them with their experimental determination
extracted from recent LHCb data. Analyzing b->s and b->sll transitions within
four different New Physics scenarios, we identify several New Physics benchmark
points which can be discriminated through the measurement of P_i observables
with a fine q^2-binning. We emphasise the importance (and risks) of using
observables with (un)suppressed dependence on soft form factors for the search
of New Physics, which we illustrate by the different size of hadronic
uncertainties attached to two related observables (P_1 and S_3). We illustrate
how the q^2-dependent angular observables measured in several bins can help to
unravel New Physics contributions to B-> K*(->Kpi)ll, and show the
extraordinary constraining power that the clean observables will have in the
near future. We provide semi-numerical expressions for these observables as
functions of the relevant Wilson coefficients at the low scale.Comment: 50 pages, 21 figures. Improved form factor analysis, conclusions
unchanged. Plots with full resolution. Version published in JHE
EOS: a software for flavor physics phenomenology
EOS is an open-source software for a variety of computational tasks in flavor physics. Its use cases include theory predictions within and beyond the Standard Model of particle physics, Bayesian inference of theory parameters from experimental and theoretical likelihoods, and simulation of pseudo events for a number of signal processes. EOS ensures high-performance computations through a C++ back-end and ease of usability through a Python front-end. To achieve this flexibility, EOS enables the user to select from a variety of implementations of the relevant decay processes and hadronic matrix elements at run time. In this article, we describe the general structure of the software framework and provide basic examples. Further details and in-depth interactive examples are provided as part of the EOS online documentation
Proceedings of the 2nd Workshop on Flavor Symmetries and Consequences in Accelerators and Cosmology (FLASY12)
These are the proceedings of the 2nd Workshop on Flavor Symmetries and
Consequences in Accelerators and Cosmology, held 30 June 2012 - 4 July 2012,
Dortmund, Germany.Comment: Order 400 pages, several figures including the group picture v2:
corrected author list and contributio
Transboundary cooperation and Mechanisms for Maritime Spatial Planning implementation. SIMNORAT Project
El proyecto SIMNORAT, Supporting Implementation of Maritime Spatial Planning in the Northern European Atlantic region (SIMNORAT), fue un proyecto cofundado por la UE de ordenaciĂłn del espacio marĂtimo desarrollado en la regiĂłn atlĂĄntica. Los objetivos del proyecto eran apoyar a los Estados miembros (EM) para aplicar la Directiva 2014/89/UE del Parlamento Europeo y del Consejo, de 23 de julio de 2014, por la que se establece un marco para la ordenaciĂłn del espacio marĂtimo (OEM); y poner en marcha y llevar a cabo iniciativas concretas y transfronterizas de OEM entre los EM participantes en el proyecto (EspaĂąa, Francia y Portugal). Para desarrollar y probar aspectos de la ordenaciĂłn del espacio marĂtimo con el fin de elaborar directrices y recomendaciones Ăştiles en un contexto transfronterizo, las autoridades competentes de los paĂses tambiĂŠn participaron en el proyecto. Los resultados de SIMNORAT, como el desarrollo de una metodologĂa conceptual para la ordenaciĂłn del espacio marĂtimo transfronterizo, el anĂĄlisis de las herramientas y los datos aplicados en el proceso de ordenaciĂłn del espacio marĂtimo, la evaluaciĂłn de las demandas y tendencias espaciales de los sectores marĂtimos, y la participaciĂłn de las partes interesadas, ayudaron a identificar las mejores prĂĄcticas en los aspectos cientĂficos, tĂŠcnicos y sociales de la ordenaciĂłn del espacio marĂtimo para una cooperaciĂłn eficaz, especialmente en las ĂĄreas de estudio de casos transfronterizos, para mejorar la aplicaciĂłn de la Directiva sobre ordenaciĂłn del espacio marĂtimo en cada paĂs con esfuerzos de colaboraciĂłn y una visiĂłn comĂşn. Esto, a su vez, puede apoyar la creaciĂłn del marco adecuado para desarrollar una economĂa azul sostenible en la regiĂłn, gestionando el sistema socioecolĂłgico asociado en un entorno cambiante
Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV
A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay
channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7
TeV is presented. The data were collected at the LHC, with the CMS detector,
and correspond to an integrated luminosity of 4.6 inverse femtobarns. No
significant excess is observed above the background expectation, and upper
limits are set on the Higgs boson production cross section. The presence of the
standard model Higgs boson with a mass in the 270-440 GeV range is excluded at
95% confidence level.Comment: Submitted to JHE
- âŚ