75 research outputs found
Two-loop Corrections to the B to pi Form Factor from QCD Sum Rules on the Light-Cone and |V(ub)|
We calculate the leading-twist O(alphas^2 beta0) corrections to the B to pi
transition form factor f+(0) in light-cone sum rules. We find that, as
expected, there is a cancellation between the O(alphas^2 beta0) corrections to
fB f+(0) and the large corresponding corrections to fB, calculated in QCD sum
rules. This suggests the insensitivity of the form factors calculated in the
light-cone sum rules approach to this source of radiative corrections. We
further obtain an improved determination of the CKM matrix element |V(ub)|,
using latest results from BaBar and Belle for f+(0)|V(ub)|.Comment: 18 pages, 3 figure
The Surgical Infection Society revised guidelines on the management of intra-abdominal infection
Background: Previous evidence-based guidelines on the management of intra-abdominal infection (IAI) were published by the Surgical Infection Society (SIS) in 1992, 2002, and 2010. At the time the most recent guideline was released, the plan was to update the guideline every five years to ensure the timeliness and appropriateness of the recommendations.
Methods: Based on the previous guidelines, the task force outlined a number of topics related to the treatment of patients with IAI and then developed key questions on these various topics. All questions were approached using general and specific literature searches, focusing on articles and other information published since 2008. These publications and additional materials published before 2008 were reviewed by the task force as a whole or by individual subgroups as to relevance to individual questions. Recommendations were developed by a process of iterative consensus, with all task force members voting to accept or reject each recommendation. Grading was based on the GRADE (Grades of Recommendation Assessment, Development, and Evaluation) system; the quality of the evidence was graded as high, moderate, or weak, and the strength of the recommendation was graded as strong or weak. Review of the document was performed by members of the SIS who were not on the task force. After responses were made to all critiques, the document was approved as an official guideline of the SIS by the Executive Council.
Results: This guideline summarizes the current recommendations developed by the task force on the treatment of patients who have IAI. Evidence-based recommendations have been made regarding risk assessment in individual patients; source control; the timing, selection, and duration of antimicrobial therapy; and suggested approaches to patients who fail initial therapy. Additional recommendations related to the treatment of pediatric patients with IAI have been included.
Summary: The current recommendations of the SIS regarding the treatment of patients with IAI are provided in this guideline
B-physics from Nf=2 tmQCD: the Standard Model and beyond
We present a lattice QCD computation of the b-quark mass, the B and B_s decay constants, the B-mixing bag parameters for the full four-fermion operator basis as well as determinations for \xi and f_{Bq}\sqrt{B_i^{(q)}} extrapolated to the continuum limit and to the physical pion mass. We used N_f = 2 twisted mass Wilson fermions at four values of the lattice spacing with pion masses ranging from 280 to 500 MeV. Extrapolation in the heavy quark mass from the charm to the bottom quark region has been carried out on ratios of physical quantities computed at nearby quark masses, exploiting the fact that they have an exactly known infinite mass limit. Our results are m_b(m_b, \overline{\rm{MS}})=4.29(12) GeV, f_{Bs}=228(8) MeV, f_{B}=189(8) MeV and f_{Bs}/f_B=1.206(24). Moreover with our results for the bag-parameters we find \xi=1.225(31), B_1^{(s)}/B_1^{(d)}=1.01(2), f_{Bd}\sqrt{\hat{B}_{1}^{(d)}} = 216(10) MeV and f_{Bs}\sqrt{\hat{B}_{1}^{(s)}} = 262(10) MeV. We also computed the bag parameters for the complete basis of the four-fermion operators which are required in beyond the SM theories. By using these results for the bag parameters we are able to provide a refined Unitarity Triangle analysis in the presence of New Physics, improving the bounds coming from B_{(s)}-\bar B_{(s)} mixing
Phenomenological aspects of the exotic quark in 331 models
In the context of 331 models we analyze the phenomenology of exotic
quarks with electric charge 2/3. We establish bounds for the corresponding
masses and mixing angles and study the decay modes , and . It
is found that the decays into scalars are strongly dependent on the model
parameters, and can be the dominant ones in a scenario with approximate flavor
symmetry.Comment: 11 pages, 2 figure
Screening toll-like receptor markers to predict latent tuberculosis infection and subsequent tuberculosis disease in a Chinese population
Prevalencija infekcije Neisseriom gonorrhoeae ili Chlamydiom trachomatis kod akutnoga mukopurulentnog cervicitisa
The aim of this study was to determine the incidence of N. gonorrhoae (NG) and/or C. trachomatis (CT) in acute mucopurulent cervicitis (MPC). The study included 617 non-pregnant women with MPC, who had not been receiving any antimicrobial treatment. The average age of patients was 22.2 years. There were no statistically significant differences according to place of residence, education, and marital status. Samples for laboratory analysis were collected using a routine procedure; NG was identified using the cytochrome oxidase test and Gram staining. CT was isolated on McCoy cell culture and stained with Lugol solution. NG was isolated in three women (0.8 %) and CT in 58 women (9.4 %). Fifty-six of the CT-positive patients were nullipara and only two were unipara. All NG-positive patients were also nullipara. The mean number of sexual partners was 2.2 in all study subjects, 2.4 in CT-positive subjects, and 2.9 in NG-positive subjects. Vaginal discharge purity according to Schröder was significantly deteriorated in CT-positive patients (p=0.011). When asked about the use of contraceptives, as many as 32.7 % patients answered that they did not use any protection, 39 % women used the rhythm method and coitus interruptus, 20 % were taking oral contraceptives, 6.1 % used mechanical devices, and 1.9 % used chemical protection. Previous acute and chronic pelvic infl ammatory diseases correlated with MPC (p<0.01). Our statistical analysis suggests that chlamydial infection significantly reduces the purity of vaginal discharge, which is more pronounced in nulliparae. Pap smear was not specific enough to demonstrate chlamydial infection. In view of the MPC findings, the prevalence of CT and NG infection is low.Cilj istraživanja jest utvrditi koincidenciju N. gonorrhoae (NG) i/ili C. trachomatis (CT) u akutnim mukopurulentnim cervicitisima (MPC). Istraživanje je provedeno na populaciji 617 žena izvan trudnoće koje prethodno nisu uzimale antimikrobnu terapiju. NG i CT su izolirane iz obrisaka vrata maternice primjenom standardnih metoda. NG je transportirana na selektivnoj hranjivoj podlozi i identificirana citokrom-oksidaznim testom bojenjem po Gramu. CT je izolirana McCoyevom staničnom kulturom nakon bojenja Lugolovom otopinom. NG je izolirana u tri ispitanice (0,8 %), a CT u 58 ispitanica (9,4 %). Srednja dob bolesnica iznosila je 22,2 godine. Školovanje i bračno stanje nisu statistički značajno utjecali na rezultate istraživanja. Među bolesnicama s izoliranom CT prevladavaju nulipare, a u slučaju NG sve su pozitivne bolesnice također bile nulipare. Srednja vrijednost broja partnera za čitavu populaciju iznosi 2,2. Bolesnice s potvrđenom CT imale su prosječno 2,4, a one s potvrđenom NG 2,9 partnera. Vrijednost određivanja stupnja čistoće rodničkog iscjetka po Schroderu značajno je povišena u CT-pozitivnih bolesnica (p=0.011). Utvrđeno je da 32.7 % ispitanica uopće nije koristilo kontracepciju, dok je većina (39 %) rabila ritmičke metode i prekinuti snošaj. Preostale ispitanice uzimale su oralne kontraceptive (20 %), mehaničku zaštitu (6,1 %) ili lokalne kemijske kontraceptive (1,9 %). Također je dokazano da prethodna akutna i kronična zdjelična upalna bolest korelira s MPC-om (p<0.01). Zaključeno je da klamidijska infekcija statistički značajno korelira sa stupnjem čistoće rodničkog iscjetka, posebice u nulipara. Papanicolaouov razmaz nije specifičan u određivanju klamidijske infekcije. Rezultati istraživanja pokazuju da je učestalost klamidijske i gonokokne infekcije ipak relativno niska u odnosu na nalaz MPC-a
QCD and strongly coupled gauge theories : challenges and perspectives
We highlight the progress, current status, and open challenges of QCD-driven physics, in theory and in experiment. We discuss how the strong interaction is intimately connected to a broad sweep of physical problems, in settings ranging from astrophysics and cosmology to strongly coupled, complex systems in particle and condensed-matter physics, as well as to searches for physics beyond the Standard Model. We also discuss how success in describing the strong interaction impacts other fields, and, in turn, how such subjects can impact studies of the strong interaction. In the course of the work we offer a perspective on the many research streams which flow into and out of QCD, as well as a vision for future developments.Peer reviewe
Societal-level versus individual-level predictions of ethical behavior: a 48-society study of collectivism and individualism
Is the societal-level of analysis sufficient today to understand the values of those in the global workforce? Or are individual-level analyses more appropriate for assessing the influence of values on ethical behaviors across country workforces? Using multi-level analyses for a 48-society sample, we test the utility of both the societal-level and individual-level dimensions of collectivism and individualism values for predicting ethical behaviors of business professionals. Our values-based behavioral analysis indicates that values at the individual-level make a more significant contribution to explaining variance in ethical behaviors than do values at the societal-level. Implicitly, our findings question the soundness of using societal-level values measures. Implications for international business research are discussed
Is small really beautiful? A review of the concept of niches in innovation
This article reviews the concept of innovation niches through three categories: strategic niche management (SNM), specialised markets and niches formed as a technology declines. In the literature, innovation niches generate interest from both innovation and marketing perspectives. This review focuses predominately on the former from which the niche types have been adopted and analysed. Mostly, contributions since 1980 have been included, representing the period of academic interest in innovative small firms, while both temporal and locational filters were applied to the study. It is noted that SNM has been proposed as a means to protect potentially useful innovations from full market competition, while specialist niches supply technologies to few customers in more stable environments. Incumbent technologies at the stage of decline may also retreat to niches where they can still remain competitive. Finally, it is suggested that further research on innovation niches would extend our understanding of technology dynamics
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