1,177 research outputs found

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

    Full text link
    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

    Manipulating graded exercise test variables affects the validity of the lactate threshold and VO2peak

    Get PDF
    Background To determine the validity of the lactate threshold (LT) and maximal oxygen uptake (V_ O2max) determined during graded exercise test (GXT) of different durations and using different LT calculations. Trained male cyclists (n = 17) completed five GXTs of varying stage length (1, 3, 4, 7 and 10 min) to establish the LT, and a series of 30-min constant power bouts to establish the maximal lactate steady state (MLSS). V_ O2 was assessed during each GXT and a subsequent verification exhaustive bout (VEB), and 14 different LTs were calculated from four of the GXTs (3, 4, 7 and 10 min)—yielding a total 56 LTs. Agreement was assessed between the highest V_ O2 measured during each GXT (V_ O2peak) as well as between each LT and MLSS. V_ O2peak and LT data were analysed using mean difference (MD) and intraclass correlation (ICC). Results The V_ O2peak value from GXT1 was 61.0 ± 5.3 mL.kg-1.min-1 and the peak power 420 ± 55 W (mean ± SD). The power at the MLSS was 264 ± 39 W. V_ O2peak from GXT3, 4, 7,10 underestimated V_ O2peak by ~1–5 mL.kg-1.min-1. Many of the traditional LT methods were not valid and a newly developed Modified Dmax method derived from GXT4 provided the most valid estimate of the MLSS (MD = 1.1 W; ICC = 0.96). Conclusion The data highlight how GXT protocol design and data analysis influence the determination of both V_ O2peak and LT. It is also apparent that V_ O2max and LT cannot be determined in a single GXT, even with the inclusion of a VEB

    Genetic assessment of population restorations of the critically endangered Silene hifacensis in the Iberian Peninsula

    Get PDF
    In order to preserve endangered plant populations and recover their evolutionary potential and ecological behavior, some restoration measures generally involve the reinforcement of the population size in existing natural populations or the reintroduction of new populations. Genetic monitoring of both natural and restored populations can provide an assessment of restoration protocol success in establishing populations that maintain levels of genetic diversity similar to those in natural populations. The highly threatened Spanish species Silene hifacensis (Caryophyllaceae) has only three natural reduced mainland populations in the Iberian Peninsula, following decline and extinction that occurred during the late 20th century. Preterit restoration strategies were essentially based on the implantation of new populations and reinforcement of certain existing populations using transplants mostly cultivated in greenhouses. In the present contribution, levels and patterns of genetic variability within natural and restored populations of Silene hifacensis were assessed using the molecular technique AFLP. Our results pointed out significant genetic diversity differences across the three existing natural populations though their population fragmentation and progressive loss of individuals have not had an impact on the global genetic diversity of this species. For restored populations, their levels of genetic diversity were similar and even higher than in natural populations. As a result, the past restoration protocols were successful in capturing similar and even higher levels of genetic diversity than those observed within natural pools. However, inbreeding processes have been detected for two restored populations. Finally, the main source of plant material for the long-time restored transplants appears to be the natural population of Cova de les Cendres. This study demonstrates, once again, how genetic markers are useful tools to be taken in consideration for endangered plant species conservation plans.Work was supported by the project CONSELLERIATERRITORIO4-06i (Conselleria de Territori i Habitage, Generalitat Valenciana)

    Visualizing Pyrazinamide Action by Live Single-Cell Imaging of Phagosome Acidification and Mycobacterium tuberculosis pH Homeostasis.

    Get PDF
    Mycobacterium tuberculosis segregates within multiple subcellular niches with different biochemical and biophysical properties that, upon treatment, may impact antibiotic distribution, accumulation, and efficacy. However, it remains unclear whether fluctuating intracellular microenvironments alter mycobacterial homeostasis and contribute to antibiotic enrichment and efficacy. Here, we describe a live dual-imaging approach to monitor host subcellular acidification and M. tuberculosis intrabacterial pH. By combining this approach with pharmacological and genetic perturbations, we show that M. tuberculosis can maintain its intracellular pH independently of the surrounding pH in human macrophages. Importantly, unlike bedaquiline (BDQ), isoniazid (INH), or rifampicin (RIF), the drug pyrazinamide (PZA) displays antibacterial efficacy by disrupting M. tuberculosis intrabacterial pH homeostasis in cellulo. By using M. tuberculosis mutants, we confirmed that intracellular acidification is a prerequisite for PZA efficacy in cellulo. We anticipate this imaging approach will be useful to identify host cellular environments that affect antibiotic efficacy against intracellular pathogens. IMPORTANCE We still do not completely understand why tuberculosis (TB) treatment requires the combination of several antibiotics for up to 6 months. M. tuberculosis is a facultative intracellular pathogen, and it is still unknown whether heterogenous and dynamic intracellular populations of bacteria in different cellular environments affect antibiotic efficacy. By developing a dual live imaging approach to monitor mycobacterial pH homeostasis, host cell environment, and antibiotic action, we show here that intracellular localization of M. tuberculosis affects the efficacy of one first-line anti-TB drug. Our observations can be applicable to the treatment of other intracellular pathogens and help to inform the development of more effective combined therapies for tuberculosis that target heterogenous bacterial populations within the host

    Evidence for the formation of two phases during the growth of SrTiO3 on silicon

    No full text
    International audienceEpitaxial SrTiO3 (STO)/Si templates open a unique opportunity for the integration of ferroelectric oxides, such as BaTiO3 on silicon and for the realization of new devices exploiting ferroelectricity. STO itself has been shown as ferroelectric at room temperature when deposited in thin layers on Si, while bulk STO is tetragonal and, thus, ferroelectric below 105 K. Here, we demonstrate the coexistence, at room temperature, of strained cubic and tetragonal phases in thin STO/Si layers. The tetragonal STO phase presents a pronounced tetragonality for thicknesses up to 24 ML. Above this thickness, the strained cubic STO phase starts relaxing while the tetragonal STO phase progressively transits to cubic STO. The origin of the simultaneous formation of these two phases is analyzed and is attributed to oxygen segregation at the early stages of the growth

    Cyclodextrins: properties and applications of inclusion complex formation

    Get PDF
    Las ciclodextrinas son macromoléculas formadas por distinto número de residuos de D(+) glucopiranosa unidos mediante enlaces a(1-4). Las más utilizadas son la a-, 13- y y-CD que contienen 6,7 y 8 moléculas de glucopiranosa respectivamente. A pesar de que son muy hidrosolubles, el interior de la cavidad de las ciclodextrinas es apolar, por lo que son capaces de formar complejos de inclusión con distintos tipos de moléculas que se alojan en su interior. La mayoría de las aplicaciones de las ciclodextrinas en la industria están encaminadas a mejorar las características del producto terminado (solubilidad, caracteres organolépticos) y a incrementar la estabilidad de los compuestos lábiles. En este artículo se comentan algunas de las aplicaciones de las ciclodextrinas en la industria farmacéutica y en catálisis química así como en química analítica. La formación de los complejos de inclusión incrementa la selectividad y la sensibilidad de la mayoría de los métodos analíticos.Cyclodextrins are macrocyclic compounds consisting of a varying number of D(+) glucopiranose residues linked through a(1-4) bonds. The most widely used are a-, 13-, y-cyclodextrins containing respectively 6,7 and 8 glucose units. In spite of their high aqueous solubility, the inner cyclodextrin cavity is non-polar and they can form complexes with many types of molecules placed inside this cavity. Most industrial applications of cyclodextrins aim at improving certain properties offmished products (solubility, organoleptic properties, stability). In this article several applications of cyclodextrins to pharmaceutical industry and chemical catalysis are reviewed. Analytical applications are al so considered, since cyclodextrin inclusion improves the sensitivity and selectivity of most analytical methods

    Physics potential of future supernova neutrino observations

    Get PDF
    We point out possible features of neutrino spectra from a future galactic core collapse supernova that will enhance our understanding of neutrino mixing as well as supernova astrophysics. We describe the neutrino flavor conversions inside the star, emphasizing the role of "collective effects" that has been appreciated and understood only very recently. These collective effects change the traditional predictions of flavor conversion substantially, and enable the identification of neutrino mixing scenarios through signatures like Earth matter effects.Comment: 8 pages, uses jpconf.cls. Talk given at Neutrino 2008, Christchurch, NZ. Some entries in Table 2 have been correcte

    Iso-singlet Down Quark Mixing And CP Violation Experiments

    Full text link
    We confront the new physics models with extra iso-singlet down quarks in the new CP violation experimental era with sin(2β)\sin{(2\beta)} and ϵ/ϵ\epsilon'/\epsilon measurements, K+π+ννˉK^+ \to \pi^+ \nu \bar{\nu} events, and xsx_s limits. The closeness of the new experimental results to the standard model theory requires us to include full SM amplitudes in the analysis. In models allowing mixing to a new isosinglet down quark, as in E6_6, flavor changing neutral currents are induced that allow a Z0Z^0 mediated contribution to BBˉB-\bar B mixing and which bring in new phases. In (ρ,η)(\rho,\eta), (xs,sin(γ))(x_s,\sin{(\gamma)}), and (xs,sin(2ϕs))(x_s, \sin{(2\phi_s)}) plots we still find much larger regions in the four down quark model than in the SM, reaching down to η0\eta \approx 0, 0sin(γ)10 \leq \sin{(\gamma)} \leq 1, .75sin(2α)0.15-.75 \leq \sin{(2\alpha)} \leq 0.15, and sin(2ϕs)\sin{(2\phi_s)} down to zero, all at 1σ\sigma. We elucidate the nature of the cancellation in an order λ5\lambda^5 four down quark mixing matrix element which satisfies the experiments and reduces the number of independent angles and phases. We also evaluate tests of unitarity for the 3×33\times3 CKM submatrix.Comment: 14 pages, 16 figures, REVTeX

    Demethylation of oligogalacturonides by FaPE1 in the fruits of the wild strawberry Fragaria vesca triggers metabolic and transcriptional changes associated with defence and development of the fruit

    Get PDF
    Ectopic expression of the strawberry (Fragariaxananassa) gene FaPE1 encoding pectin methyl esterase produced in the wild species Fragaria vesca partially demethylated oligogalacturonides (OGAs), which conferred partial resistance of ripe fruits to the fungus Botrytis cinerea. Analyses of metabolic and transcriptional changes in the receptacle of the transgenic fruits revealed channelling of metabolites to aspartate and aromatic amino acids as well as phenolics, flavanones, and sesquiterpenoids, which was in parallel with the increased expression of some genes related to plant defence. The results illustrate the changes associated with resistance to B. cinerea in the transgenic F. vesca. These changes were accompanied by a significant decrease in the auxin content of the receptacle of the ripe fruits of transgenic F. vesca, and enhanced expression of some auxin-repressed genes. The role of these OGAs in fruit development was revealed by the larger size of the ripe fruits in transgenic F. vesca. When taken together these results show that in cultivated F. ananassa FaPE1 participates in the de-esterification of pectins and the generation of partially demethylated OGAs, which might reinforce the plant defence system and play an active role in fruit development
    corecore