Search

In this review we present and discuss the determination of the magnitude of the Cabibbo–Kobayashi–Maskawa (CKM) matrix parameter Vcb. The CKM matrix parametrizes the weak charged current interactions of quarks in the standard model (SM), and a precise determination of its elements has always been one of the most important targets of particle physics. The precise knowledge of the |Vcb| value plays a pivotal role in testing the flavour sector of the SM and in the analyses of the unitarity of the CKM matrix. The SM does not predict the values of the CKM matrix elements, which have to be extracted by experimental data. Given the variety of channels that allow the extraction of |Vcb|, different theoretical and experimental techniques are mustered for the |Vcb| determination. The exertion towards precision represents not only a significant test of our theoretical procedures but a stimulus towards better detection performances. The most precise measurements of |Vcb| come from semileptonic decays, that being tree level at the lowest order in the SM are generally considered unaffected by physics beyond the SM. After summarizing the characteristics of the SM that set the frame for the determination of |Vcb|, we discuss inclusive and exclusive semileptonic B decays. We analyse the |Vcb| extraction methods and recent results, detailing both the theoretical and experimental techniques, and, finally, outline future prospects. We also comment on exclusive decays into heavy leptons, on the observables R(D) and R(D*), on decays to excited D meson states and on baryon decays. [ABSTRACT FROM AUTHOR]

Objectives: The use of short implants has been suggested in recent years as an option for facilitating prosthetic restoration in resorbed jawbones. The aim of the present study was to determine how implant success rate is affected in the long term when ultra-short implants are rehabilitated with fixed restorations, resulting in a crown to implant (C/I) ratio of more than 3:1. Materials and methods: The study was conducted as an analysis on all patients operated from December 2005 to November 2007 with ultra-short dental implants. All implants were sintered porous-surfaced (SPS) with a length of 5 mm and a diameter of 5 mm (5 × 5 mm) and were restored with a single crown or a fixed dental prosthesis (FDP). Data collected included implant positioning site, crestal bone levels (CBL), and clinical and anatomical C/I ratios, and pre-established success criteria were used to evaluate the success rate of the implants. Statistical analysis was used to determine any significant differences or correlations (p = 0.05). Results: Forty-one patients completed the follow-up and were eligible for this retrospective study on a total of 50 ultra-short SPS implants. The mean follow-up was 9.5 years (range 8.3 to 10.2 years). Three of the 50 implants failed because they were lost due to peri-implantitis, while all the other 47 met the pre-established success criteria giving an overall implant success rate of 94%. During the follow-up period, the mean peri-implant bone loss (PBL) was 0.41 + 0.36 mm. Conclusions: This study shows that ultra-short SPS implants can prove a reliable solution for prosthetic restoration in patients with severe alveolar bone atrophy. In selected patients with a sufficient bone width, ultra-short implants with a resulting C/I ratio of more than 3:1 presented no contraindications. Clinical relevance: In selected cases, ultra-short implants may represent an alternative to bone augmentation procedures and a long-term predictable solution. [ABSTRACT FROM AUTHOR]

We summarize the status of semileptonic and leptonic B decays, including and exclusive and inclusive determinations, decays to excited states of the charm meson spectrum and decays into leptons. [ABSTRACT FROM AUTHOR]

Conventional signals are maintained via social costs and commonly used in the animal kingdom to assess conspecifics' agonistic ability during disputes over resources. In the last decade, some experimental studies reported the existence of visual conventional signals in several social wasp species, being good rank predictors in different social contexts. Females of the social wasp Polistes gallicus do not cooperate to start nests but they often try to usurp conspecific nests. Here, we showed that the reproductive females of this species have variable facial colour patterns that function as conventional signals. Wasps with larger black spots on their clypeus are more likely to successfully overwinter, are larger, and are better at fighting and at holding a nest. Furthermore, in field experiments, resident foundresses rely on facial pattern to assess usurpers' fighting abilities, modulating their defence reaction accordingly, so that rivals with larger black spot receive more aggression than rivals with smaller or no black spots on the clypeus. Our study reveals that visual recognition abilities are widespread among paper wasps that, regardless of their social biology, face similar selective pressures within competitive contexts. [ABSTRACT FROM AUTHOR]

We report on the current status of semi-leptonic B(s) decays, including rare decays, and the extraction of the absolute values of the CKM matrix elements |Vcb| and |Vub|. [ABSTRACT FROM AUTHOR]

We review the current status of |Vcb|, |Vub| and |Vtb|, the absolute values of the matrix elements in the CKM third column. [ABSTRACT FROM AUTHOR]

We concisely review semileptonic B-decays, focusing on recent progress on both theo-retical and experimental sides [ABSTRACT FROM AUTHOR]

As it is well known, large threshold logarithmic contributions can be resummed in the form factors within a fixed order approximation. Such form factors, however, are divergent at large x, as a consequence of the QCD coupling hitting the Landau pole in the resumming procedure. A possible solution is presented here, and it requires using an effective coupling which takes into account additional –usually neglected– absorptive physical effects; as a consequence, the theory becomes completely predictive with regular form factors at large x. These results are pertinent to a wide class of phenomenological applications, and in particular are of interest for processes at the B meson mass scale. [ABSTRACT FROM AUTHOR]

• A higher CHA 2 DS 2 -VASc score is correlated to higher cytokine levels • The CHA 2 DS 2 -VASc score is an expression of a complex clinical status • The CHA 2 DS 2 -VASc score is inversely associated with SPPB, an index of frailty • An association also exists between IL-6 levels and frailty • In AF, inflammation could mediate the link between CHA 2 DS 2 -VASc score and frailty [ABSTRACT FROM AUTHOR]

The article discusses a study which examines cases of interspecific feeding of an Eurasian coot Fulica atra chick by an adult non breeding whiskered tern Chlidonias hybrida in a wetland in Central Italy in May 2013. Based on the results, it is suggested that the behavior of the tern was triggered by the begging of the chick or by its own hormonal status. Topics include implications of the interspecific altruistic behavior for the species and how the observations were done.

Abstract: We compare experimental spectra of radiative and semileptonic B decays with the predictions of a model based on soft-gluon resummation to next-to-next-to-leading order and on a ghost-less time-like coupling. We find a good agreement with photon spectra in the radiative decay and with hadron mass distributions in the semileptonic one: the extracted values for are in agreement with the current PDG average within at most two standard deviations. The agreement is instead less good for the electron spectra measured by BaBar and Belle in semileptonic decays for small electron energies (): our spectrum is harder. We also show that, in general, the inclusion of next-to-next-to-leading order effects is crucial for bringing the model closer to the data and that the non-power expansion introduced in the framework of analytic coupling studies does not accurately describe soft-gluon effects. [Copyright &y& Elsevier]

Massive gravitational modes in effective field theories can be recovered by extending General Relativity and taking into account generic functions of the curvature invariants, not necessarily linear in the Ricci scalar R. In particular, adopting the minimal extension of f(R) gravity, an effective field theory with massive modes is straightforwardly recovered. This approach allows to evade shortcomings like ghosts and discontinuities if a suitable choice of expansion parameters is performed. [ABSTRACT FROM AUTHOR]