Padé and Gregory error estimates for the logarithm of block triangular matrices

In this paper we give bounds for the error arising in the approximation of the logarithm of a block triangular matrix T by Padé approximants of the function f(x)=log[(1+x)/(1-x)] and partial sums of Gregory's series. These bounds show that if the norm of all diagonal blocks of the Cayley-transform B=(T-I)(T+I)-1 is sufficiently close to zero, then both approximation methods are accurate. This will contribute for reducing the number of successive square roots of T needed in the inverse scaling and squaring procedure for the matrix logarithm.http://www.sciencedirect.com/science/article/B6TYD-4G5BJ9P-2/1/398a212a906943d2474a2cd6166c1d3

Improved burn wound healing using a bioactive peptide

[Excerpt] Antimicrobial peptides (AMPs) are good candidates to treat burn wounds, a major cause of morbidity, impaired life quality and resources consumption in developed countries. We took advantage of a commercially available hydrogel, Carbopol, a vehicle for topical administration that maintains a moist environment within the wound site. We hypothesized that the incorporation of LLKKK18 conjugated to dextrin would improve the healing process in rat burns. Whereas the hydrogel improves healing, LLKKK18 released from the dextrin conjugates further accelerates wound closure, and simultaneously improving the quality of healing. Indeed, the release of LLKKK18 reduces oxidative stress and inflammation (low neutrophil and macrophage infiltration and pro-inflammatory cytokines levels). Importantly, it induced a faster resolution of the inflammatory stage through early M2 macrophage recruitment. In addition, LLKKK18 stimulates angiogenesis (increased VEGF and microvessel development in vivo), potentially contributing to more effective transport of nutrients and cytokines. Moreover, collagen staining evaluated by Masson’s Trichrome was visually much more intense after treatment with LLKKK18, suggesting higher collagen deposition. (...

Bounds on gamma from CP violation measurements in B -> pi+ pi- and B -> psi K_S

We study the determination of gamma from CP-violating observables in B -> pi+ pi- and B -> psi K_S. This determination requires theoretical input to one combination of hadronic parameters. We show that a mild assumption about this quantity may allow bounds to be placed on gamma, but we stress the pernicious effects that an eightfold discrete ambiguity has on such an analysis. The bounds are discussed as a function of the direct (C) and interference (S) CP-violating observables obtained from time-dependent B -> pi+ pi- decays, and their behavior in the presence of new physics effects in B-Bbar mixing is studied. (V2: Misprints corrected. Slightly improved discussion.)Comment: 11 pages, RevTex 4, 5 eps figures include

Reparametrization invariance of B decay amplitudes and implications for new physics searches in B decays

When studying B decays within the Standard Model, it is customary to use the unitarity of the CKM matrix in order to write the decay amplitudes in terms of only two of the three weak phases which appear in the various diagrams. Occasionally, it is mentioned that those two weak phases can be used in order to describe any decay amplitude, even beyond the Standard Model. Here we point out that, when describing a generic decay amplitude, the two weak phases can be chosen completely at will, and we study the behavior of the decay amplitudes under changes in the two weak phases chosen as a basis. Of course, physical observables cannot depend on such reparametrizations. This has an impact in discussions of the SM and in attempts to parametrize new physics effects in the decay amplitudes. We illustrate these issues by looking at B --> psi K_S and the isospin analysis in B --> pi pi.Comment: 16 pages, RevTe

Planning forest recreation: environmental economic instruments and the public participation

In Portugal there is a growing demand for natural areas that provide a wide range of outdoor recreation. This paper focuses on the particular case of the Mata Nacional de Leiria (Leiria National Forest). This is a pine tree forest with 11,000 hectares and eight centuries of history. It has always been a public forest with open access to everyone, a fact that contributes to different kinds of use and benefits (walking, cycling, picnics, collecting firewood, fruits and berries, and other recreation activities). The proximity to a major urban and industrial centre, on one hand, and to a very popular beach coast, on the other, makes this a resource that is widely used by both residents and visitors. In the future there is the possibility of implementing a set of actions to improve forest amenities and recreation, and later the emergence of environmental tourism activities and equipment. In this context, we want to know the economic valuation that actual users attach to these recreation improvements, but also realize their preferences and opinions regarding this project. For this purpose we designed, tested and applied a double bounded dichotomous choice contingent valuation questionnaire. The results presented in this paper focus on responses to attitudinal and follow-up questions. More than 70% of respondents have positively assessed the proposed improvements to the study area and about 40% enhanced their personal opinion on the type of interventions that they consider most appropriate. Answers focus the priority areas of intervention in the Mata Nacional de Leiria, the main concerns in its development, the type of actions that should (and should not) be implemented, respondents willingness to actively take part and, also, what the public authorities' role should be. At this stage, where Mata Nacional de Leiria is being considered in terms of future recreation and tourism offers, the results obtained provide important contributions and enhance the contingent valuation survey as a tool to support recreation planning, promoting public participation and the political decision-making process

Influence of cross section geometry on the confinement of reinforced concrete columns with CFRP composites

Comunicação apresentada em International Symposium Polymers in Concrete (ISPIC 2006), Guimarães, 2006Confinement effectiveness of externally bonded FRP jackets depends on different parameters namely type of concrete, steel reinforcement, FRP jacket stiffness (type of FRP, number of plies and design of wrap), shape of cross section, radius of corners for non-circular sections, and loading conditions. In order to investigate the effect of some of these parameters on the axial behavior of columns under compression and to quantify the level of confinement exerted on the concrete core, an experimental program has been developed. The experimental research consisted of a sequence of axial compressive tests on cylinders and square prisms. Prisms were divided into three representative groups: sharpedged sections and sections with rounded corners with corner radii equal to either 20mm or 38mm. The results presented in this paper are for the columns which were wrapped with two plies of unidirectional carbon fibers

Processing of continuous fibre reinforced thermoplastics

ECCM15 - 15TH EUROPEAN CONFERENCE ON COMPOSITE MATERIALS, Venice, Italy, 24-28 June 2012Towpregs based on different fibres and thermoplastic matrices were processed for highly demanding and more commercial applications by different composite processing technologies. In the technologies used, compression moulding and pultrusion, the final composite pr ocessing parameters were studied in order to obtain composites with adequate properties at industrial compatible production rates. The produced towpregs were tested to verify its polymer content and degree of impregnation. The obtained results have shown t hat the coating line enabled to produce, with efficiency and industrial scale speed rates, thermoplastic matrix towpregs that may be used to manufacture composites for advanced and larger volume commercial markets