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Search Results: 1 - 10 of 457183 matches for " I. M. Pepe "
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T. Pepe,M. Ceruso,A. Carpentieri,I. Ventrone
Italian Journal of Food Safety , 2011, DOI: 10.4081/ijfs.2011.1s.177
Abstract: An accurate identification of similar fish species is necessary to prevent illegal substitution and is imposed by labeling regulations in UE countries (1). The genus Thunnus comprises many species of different quality and commercial value. The increasing trade of fish preparations of the species included in this genus and the consequent loss of the external anatomical and morphological features enables fraudulent substitutions. This study reports data relating to the proteomic analysis of four tuna species (T. thynnus, T. alalunga, T. albacares, T. obesus). Sarcoplasmic proteins were studied by mono and two dimensional electrophoresis. The most significant proteins for the characterization of the species were analyzed by mass spectrometric techniques. As reported in a previous study (2), an accurate identification of the species seems possible, owing to the polymorphism displayed by the species of the Thunnus genus.
T. Pepe,I. Ventrone,E. Suffredini,M. Ceruso
Italian Journal of Food Safety , 2013, DOI: 10.4081/ijfs.2010.7.61
Abstract: Shellfish are recognized as a potential vehicle of viral diseases. However, according to European Regulations, only bacteriological parameters (Salmonella and E. coli) are used to establish their microbiological quality. Because of the lack of a standard reference method for the detection of viruses, data on the incidence of enteric viruses in European production areas are still limited. Aim of the present study was the evaluation of the Norovirus (NoV) contamination in shellfish from different harvesting areas (both class A and B) and from registered and not- registered retails of the Campania region (Tyrrhenian Sea, Italy). Seventy shellfish (Mytilus galloprovincialis) were collected from 15 harvesting areas, one authorized and two not authorized retails and were examined for virus presence (NoV genogroups I and II) by Real Time PCR. Ten harvesting areas (66%) showed presence of viral contamination, with three of them belonging to A areas and seven to B areas. The shellfish collected from the registered retail tested positive for Norovirus presence, whereas the shellfish collected from not-authorized retails didn’t show viral contamination. Twenty-nine samples were positive for genogroup II, ten of which tested positive also for NoV genogroup I.
Field transformation and Monte Carlo simulations
M. Pepe
Physics , 1998, DOI: 10.1016/S0920-5632(99)85225-6
Abstract: A new method to compute observables at many values of the parameters \lambda for a model with lattice action {\cal{S}}(\phi, \lambda) is described. After fixing a reference set \lambda^r of parameters, a single simulation is carried out by using a ``reference action'' {\cal{S}} (\phi^r, \lambda^r) to generate configurations of the field \phi^r. Then a suitable analytic transformation is performed from the configurations of \phi^r to the ones corresponding to the action {\cal{S}} (\phi, \lambda). Such a transformation allows to obtain the observables for values of the parameters \lambda close to \lambda^r. I present studies on the reliability of the algorithm in the case of the \phi^4 model in 2 dimensions.
Deconfinement in Yang-Mills: a conjecture for a general gauge Lie group G
M. Pepe
Physics , 2004, DOI: 10.1016/j.nuclphysbps.2004.12.036
Abstract: Svetitsky and Yaffe have argued that -- if the deconfinement phase transition of a (d+1)-dimensional Yang-Mills theory with gauge group G is second order -- it should be in the universality class of a d-dimensional scalar model symmetric under the center C(G) of G. These arguments have been investigated numerically only considering Yang-Mills theory with gauge symmetry in the G=SU(N) branch, where C(G)=Z(N). The symplectic groups Sp(N) provide another extension of SU(2)=Sp(1) to general N and they all have the same center Z(2). Hence, in contrast to the SU(N) case, Sp(N) Yang-Mills theory allows to study the relevance of the group size on the order of the deconfinement phase transition keeping the available universality class fixed. Using lattice simulations, we present numerical results for the deconfinement phase transition in Sp(2) and Sp(3) Yang-Mills theories both in (2+1)d and (3+1)d. We then make a conjecture on the order of the deconfinement phase transition in Yang-Mills theories with general Lie groups SU(N), SO(N), Sp(N) and with exceptional groups G(2), F(4), E(6), E(7), E(8). Numerical results for G(2) Yang-Mills theory at finite temperature in (3+1)d are also presented.
String effects in Yang-Mills theory
M. Pepe
Physics , 2010,
Abstract: We study some features of the confining string connecting a quark-anti-quark pair in Yang-Mills theory. Monte Carlo investigations of the flux tube between two static quarks in the fundamental representation show that its thickness increases with the separation of the sources. The collected numerical data in (2+1)-d SU(2) Yang-Mills theory are in very good quantitative agreement with the next-to-leading order formula derived from the systematic low-energy effective theory of the confining string. At zero temperature, we observe the predicted logarithmic broadening. At finite and low temperature, the flux tube thickness is expected to broaden linearly. We also verify that prediction, finding an excellent agreement with the analytic expression. No adjustable parameter has been used to fit the numerical data. Then we investigate the confining strings connecting color sources in larger representations of the gauge group. Concerning stable strings -- the k-strings -- we study the Luscher term of the fundamental string and of the 2-string in (2+1)-d SU(4) Yang-Mills theory. We find that, at large separation between the two static sources, the coefficient of the Luscher term of the 2-string appraoches the value -pi/24. However, at intermediate distances, there are relevant deviations. This result may suggest that, for SU(N) at large N, a different intermediate string regime could set in. For unstable strings, in (2+1)-d SU(2) Yang-Mills theory we investigate the decay between two different string states and the multiple decays of the confining string connecting color sources in large representations. The multiple decays result from the progressive partial screening of the color sources.
El splicing alternativo del exón 5 de la citocromo p450 aromatasa podría ser un mecanismo de regulación de la producción de estrógenos en humanos Exon 5 alternative splicing of the cytochrome P450 aromatase could be a regulatory mechanism for estrogen production in humans
Carolina M. Pepe,Nora I. Saraco,María Sonia Baquedano,Gabriela Guercio
Medicina (Buenos Aires) , 2007,
Abstract: La enzima P450 aromatasa (P450Aro) participa en la síntesis de estrógenos a partir de andrógenos. La mutación c655G>A, descripta en forma heterocigota en una ni a y en forma homocigota en un hombre adulto, ambos con déficit de aromatasa, genera la disrupción del sitio dador de splicing exón5-intrón5. Se ha postulado que la retención del intrón5 y la generación de una proteína truncada inactiva serían las consecuencias de esta mutación. Sorpresivamente, la paciente presentó desarrollo espontáneo de mamas y niveles puberales de estradiol, sugiriendo una actividad aromatasa (AA) residual. En principio postulamos que la mutación c655G>A generaría la pérdida del exón5 con conservación del marco de lectura, generándose una proteína con menor actividad que podría explicar el déficit parcial. La expresión del ARNm sin exón5 (ARNm- E5) en linfocitos de la paciente sugiere una asociación entre la pérdida del exón y la presencia de la mutación; posteriormente confirmada realizando ensayos de splicing en células Y1. Sin embargo, la expresión del cDNAE5 en células Y1 presentó una AA nula que no explicaría un déficit parcial. La expresión del ARNm-E5 fue detectada en placenta, testículo y adrenal humanos como una variante de splicing normal. Estos resultados indicarían la ocurrencia de splicing alternativo (SA) en la zona codificante de P450Aro como un posible mecanismo regulador de la producción de estrógenos en tejidos esteroidogénicos humanos. La mutación c655G>A podría alterar los mecanismos fisiológicos reguladores del SA del exón5 favoreciendo su exclusión. De esta forma, bajos niveles de ARNm+E5 podrían expresarse aun en presencia de la mutación explicando el fenotipo de déficit parcial observado en la paciente. P450 aromatase (P450Aro), involved in androgen to estrogen conversion, is encoded by the CYP19 gene. P450Aro c655G>A mutation described in heterozygous form in a girl and in homozygous form in an adult male with P450Aro deficiency results in an aberrant splicing due to disruption of a donor splice site. A truncated inactive protein would be expected if intron5 is retained. Surprisingly, the girl described with this mutation showed spontaneous breast development and pubertal estradiol (E2) levels suggesting residual P450Aro activity (AA). Formerly, we postulate the in frame E5 skipping as a consequence of this mutation generating a protein with some degree of activity. When P450Aro mRNA expression was analysed from patient's lymphocytes, an aberrant spliced mRNA lacking E5 (-E5mRNA) was detected, suggesting an association between E5 skipping and the pre
Higgs Searches and Prospects from LEP2
M. Pepe-Altarelli
Physics , 1999,
Abstract: The status of the search at LEP2 for the Higgs in the Standard Model (SM) and in the minimal supersymmetric extension of the Standard Model MSSM) is reviewed. A preliminary lower limit of 95.5/c^2 at 95% C.L. on the SM Higgs is obtained after a preliminary analysis of the data collected at sqrt(s)= 189 GeV. For standard choices of MSSM parameter sets, the search for the neutral Higgs bosons h and A leads to preliminary 95% C.L. exclusion lower limits of 83.5GeV/c^2 and 84.5 GeV/c^2, respectively.
Four loop results for the 2D O(n) nonlinear sigma model with 0-loop and 1-loop Symanzik actions
B. Alles,M. Pepe
Physics , 1999, DOI: 10.1016/S0920-5632(00)91783-3
Abstract: We present complete three loop results and preliminary four loop results for the 2D O(n) nonlinear sigma model with 0-loop and 1-loop Symanzik improved actions. This calculation aims to test the improvement in the numerical precision that the combination of Symanzik actions and effective couplings can give in Monte Carlo simulations.
W physics at LEP
M. Pepe-Altarelli
Physics , 1998,
Abstract: A summary of the W-boson properties measured by the four LEP collaborations is presented here. These properties are updated to take into account the most recent results presented at the ICHEP98 conference.
Four-loop free energy for the 2D O(n) nonlinear sigma-model with 0-loop and 1-loop Symanzik improved actions
B. Alles,M. Pepe
Physics , 1999, DOI: 10.1016/S0550-3213(99)00604-5
Abstract: We calculate up to four loops the free energy of the two-dimensional (2D) O(n) nonlinear sigma-model regularized on the lattice with the 0-loop and 1-loop Symanzik improved actions. An effective coupling constant based on this calculation is defined.
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