New results from the lattice on the theoretical inputs to the hadronic tau determination of V_us

Recent sum rule determinations of |V_us|, employing flavor-breaking combinations of hadronic tau decay data, are significantly lower than either expectations based on 3-family unitarity or determinations from K_ell3 and Gamma[K_mu2]/Gamma[pi_mu2]. We use lattice data to investigate the accuracy/reliability of the OPE representation of the flavor-breaking correlator combination entering the tau decay analyses. The behavior of an alternate correlator combination, constructed to reduce problems associated with the slow convergence of the D = 2 OPE series, and entering an alternate sum rule requiring both electroproduction cross-section and hadronic tau decay data, is also investigated. Preliminary updates of both analyses, with the lessons learned from the lattice data in mind, are also presented.Comment: 8 pages, 5 figures. Prepared for the proceedings of the 12th International Workshop on Tau Lepton Physics, Sep. 17-21, 2012, Nagoya, Japan and the 10th International Conference on Confinement and the Hadron Spectrum, Oct. 6-13, 2012, Garching/Munich, German

Some continuum physics results from the lattice V-A correlator

We present preliminary results on extractions of the chiral LECs L_10 and C_87 and constraints on the excited pseudoscalar state pi(1300) and pi(1800) decay constants obtained from an analysis of lattice data for the flavor ud light quark V-A correlator. A comparison of the results for the correlator to the corresponding mildly-model-dependent continuum results (based primarily on experimental hadronic tau decay data) is also givenComment: 7 pages, 3 figures. Prepared for the Proceedings of the 30th International Symposium on Lattice Field Theory, Cairns, Australia, June 24-29, 2012; expanded version of Reference 1

Energetics of metal slabs and clusters: the rectangle-box model

An expansion of energy characteristics of wide thin slab of thickness L in power of 1/L is constructed using the free-electron approximation and the model of a potential well of finite depth. Accuracy of results in each order of the expansion is analyzed. Size dependences of the work function and electronic elastic force for Au and Na slabs are calculated. It is concluded that the work function of low-dimensional metal structure is always smaller that of semi-infinite metal sample. A mechanism for the Coulomb instability of charged metal clusters, different from Rayleigh's one, is discussed. The two-component model of a metallic cluster yields the different critical sizes depending on a kind of charging particles (electrons or ions). For the cuboid clusters, the electronic spectrum quantization is taken into account. The calculated critical sizes of Ag_{N}^{2-} and Au_{N}^{3-} clusters are in a good agreement with experimental data. A qualitative explanation is suggested for the Coulomb explosion of positively charged Na_{\N}^{n+} clusters at 3<n<5.Comment: 11 pages, 6 figures, 1 tabl

Long-distance dimension-eight operators in B_K

Besides their appearance at short distances \gtrsim 1/M_W, local dimension-eight operators also contribute to kaon matrix elements at long distances of order \gtrsim 1/mu_ope, where mu_ope is the scale controlling the Operator Product Expansion in pure QCD, without weak interactions. This comes about in the matching condition between the effective quark Lagrangian and the Chiral Lagrangian of mesons. Working in dimensional regularization and in a framework where these effects can be systematically studied, we calculate the correction from these long-distance dimension-eight operators to the renormalization group invariant B_K factor of K^0-K^0bar mixing, to next-to-leading order in the 1/Nc expansion and in the chiral limit. The correction is controlled by the matrix element <0|\bar s_L \tilde{G}_{mu nu}gamma^mu d_L|K^0>, is small, and lowers B_K.Comment: 14 pages, LaTeX. Explanatory comments added to match version in journa

A Combined NNLO Lattice-Continuum Determination of L10rL_{10}^r

The renormalized next-to-leading-order (NLO) chiral low-energy constant, $L_{10}^r$, is determined in a complete next-to-next-to-leading-order (NNLO) analysis, using a combination of lattice and continuum data for the flavor $ud$ $V-A$ correlator and results from a recent chiral sum-rule analysis of the flavor-breaking combination of $ud$ and $us$ $V-A$ correlator differences. The analysis also fixes two combinations of NNLO low-energy constants, the determination of which is crucial to the precision achieved for $L_{10}^r$. Using the results of the flavor-breaking chiral $V-A$ sum rule obtained with current versions of the strange hadronic $\tau$ branching fractions as input, we find $L_{10}^r(m_\rho )\, =\, -0.00346(32)$. This result represents the first NNLO determination of $L_{10}^r$ having all inputs under full theoretical and/or experimental control, and the best current precision for this quantity.Comment: 21 pages, 4 figures, 1 table. Updated references, one additional clarifying footnote in discussion sectio

Lattice Input on the Inclusive ττ Decay VusV_{us} Puzzle

Recent analyses of flavor-breaking hadronic-$\tau$-decay-based sum rules produce values of $\vert V_{us}\vert$ $\sim 3\sigma$ low compared to 3-family unitarity expectations. An unresolved systematic issue is the significant variation in $\vert V_{us}\vert$ produced by different prescriptions for treating the slowly converging $D=2$ OPE series. We investigate the reliability of these prescriptions using lattice data for various flavor-breaking correlators and show the fixed-scale prescription is clearly preferred. Preliminary updates of the conventional $\tau$-based, and related mixed $\tau$-electroproduction-data-based, sum rule analyses incorporating B-factory results for low-multiplicity strange $\tau$ decay mode distributions are then performed. Use of the preferred FOPT $D=2$ OPE prescription is shown to significantly reduce the discrepancy between 3-family unitarity expectations and the sum rule results.Comment: 5 pages, 2 figures. Contribution to the proceedings of the International Workshop on e^+ e^- Collisions from Phi to Psi, 201

Spinal infection: state of the art and management algorithm

Spinal infection is a rare pathology although a concerning rising incidence has been observed in recent years. This increase might reflect a progressively more susceptible population but also the availability of increased diagnostic accuracy. Yet, even with improved diagnosis tools and procedures, the delay in diagnosis remains an important issue. This review aims to highlight the importance of a methodological attitude towards accurate and prompt diagnosis using an algorithm to aid on spinal infection management. METHODS: Appropriate literature on spinal infection was selected using databases from the US National Library of Medicine and the National Institutes of Health. RESULTS: Literature reveals that histopathological analysis of infected tissues is a paramount for diagnosis and must be performed routinely. Antibiotic therapy is transversal to both conservative and surgical approaches and must be initiated after etiological diagnosis. Indications for surgical treatment include neurological deficits or sepsis, spine instability and/or deformity, presence of epidural abscess and upon failure of conservative treatment. CONCLUSIONS: A methodological assessment could lead to diagnosis effectiveness of spinal infection. Towards this, we present a management algorithm based on literature findings

Bacteriophage-encoded depolymerases: their diversity and biotechnological applications

Bacteriophages (phages), natural enemies of bacteria, can encode enzymes able to degrade polymeric substances. These substances can be found in the bacterial cell surface, such as polysaccharides, or are produced by bacteria when they are living in biofilm communities, the most common bacterial lifestyle. Consequently, phages with depolymerase activity have a facilitated access to the host receptors, by degrading the capsular polysaccharides, and are believed to have a better performance against bacterial biofilms, since the degradation of extracellular polymeric substances by depolymerases might facilitate the access of phages to the cells within different biofilm layers. Since the diversity of phage depolymerases is not yet fully explored, this is the first review gathering information about all the depolymerases encoded by fully sequenced phages. Overall, in this study, 160 putative depolymerases, including sialidases, levanases, xylosidases, dextranases, hyaluronidases, peptidases as well as pectate/pectin lyases, were found in 143 phages (43 Myoviridae, 47 Siphoviridae, 37 Podoviridae, and 16 unclassified) infecting 24 genera of bacteria. We further provide information about the main applications of phage depolymerases, which can comprise areas as diverse as medical, chemical, or food-processing industry.DPP acknowledges the financial support from the Portuguese Foundation for Science and Technology (FCT) through the grant SFRH/BD/76440/2011. SS is an FCT investigator (IF/01413/2013). The authors also thank FCT for the Strategic Project of the UID/BIO/04469/2013 unit, FCT and European Union funds (FEDER/COMPETE) for the project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER027462)