A Short Guide to Flavour Physics and CP Violation

We present the invited lectures given at the second Asia-Europe-Pacific School of High-Energy Physics (AEPSHEP), which took place in Puri, India in November 2014. The series of lectures aimed at graduate students in particle experiment/theory, covering the very basics of flavor physics and CP violation, some useful theoretical methods such as OPE and effective field theories, and some selected topics of flavour physics in the era of LHC.Comment: 51 pages, 19 figures, paper submitted for publication in a CERN Yellow Report (YR

Pneumocéfalo Espontâneo Hipertensivo

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Anarchic Yukawas and top partial compositeness: the flavour of a successful marriage

The top quark can be naturally singled out from other fermions in the Standard Model due to its large mass, of the order of the electroweak scale. We follow this reasoning in models of pseudo Nambu Goldstone Boson composite Higgs, which may derive from an underlying confining dynamics. We consider a new class of flavour models, where the top quark obtains its mass via partial compositeness, while the lighter fermions acquire their masses by a deformation of the dynamics generated at a high flavour scale. One interesting feature of such scenario is that it can avoid all the flavour constraints without the need of flavour symmetries, since the flavour scale can be pushed high enough. We show that both flavour conserving and violating constraints can be satisfied with top partial compositeness without invoking any flavour symmetry for the up-type sector, in the case of the minimal SO(5)/SO(4) coset with top partners in the four-plet and singlet of SO(4). In the down-type sector, some degree of alignment is required if all down-type quarks are elementary. We show that taking the bottom quark partially composite provides a dynamical explanation for the hierarchy causing this alignment. We present explicit realisations of this mechanism which do not require to include additional bottom partner fields. Finally, these conclusions are generalised to scenarios with non-minimal cosets and top partners in larger representations.Comment: 37 pages, 1 figure, v2: typos fixed, Eq. (3.44) added, version corresponds to published article in JHE

Computing the zeros of quaternion polynomials

A method is developed to compute the zeros of a quaternion polynomial with all terms of the form qkXk. This method is based essentially in Niven's algorithm [1], which consists of dividing the polynomial by a characteristic polynomial associated to a zero. The information about the trace and the norm of the zero is obtained by an original idea which requires the companion matrix associated to the polynomial. The companion matrix is represented by a matrix with complex entries. Three numerical examples using Mathematica 2.2 version are given.http://www.sciencedirect.com/science/article/B6TYJ-444G6J6-N/1/2ab1f648c1929ffc5374c2a8b11c2a7

A 2d in vivo approach to study photosynthesis in grape berry

Is argued that fruit photosynthesis serves mainly as a respiratory CO2 refixation mechanism [1] but its contribution to growth and metabolism, localization and dynamics during fruit development are poorly known. Unlike the leaves, fruit volume imposes a constraint to photosynthesis by limiting light penetration. However, the patterns of chlorophyll distribution are apparently independent of a light intensity gradient. Microscopic observations of transversal slices of green stage grape berries (6-8 weeks after fruit set) of Alvarinho cultivar, revealed that exocarp cells, mesocarp cells next to vascular bundles, and seed coat cells present higher chlorophyll contents than inner mesocarp cells. The photosynthetic activity was determined on this material by Imaging-PAM fluorometry, a powerful tool for 2D mapping of in vivo photosynthesis. In 2 mm-thick grape berry discs, chlorophyll fluorescence parameters were estimated (Fv/Fm and II), and rapid light curves (RLC) were performed. Exocarp and seed coats of green berries showed the highest Fv/Fm values (ca. 0.6-0.7), and mesocarp cells around 85% of that value. Exocarp from mature grapes maintained Fv/Fm values during maturation, but in mesocarp and seed coats this value strongly decreased. ETRr were very sensitive to increasing light intensities and decreased with grape berry maturation. Our future prospects include the implication of photosynthesis on grape berry solute contents (sugars, acids), fruit and seed development.Fundação para a Ciência e a Tecnologia (research project no. PTDC/AGR-ALI/100636/2008

In vitro cultures of grape tissues: new possibilities to study grape berry physiology

Grape berries suffer important morphological, biochemical and physiological changes during its development and maturation. It is known that photoassimilates translocated from leaves serve as the major source of carbon and energy to support fruit needs, but recent findings revealed that, at least in the green phase, grape berries show high photosynthetic activity especially in the exocarp. The contribution of fruit photosynthesis for fruit growth and production of organic compounds is far from being understood. In this study photomixotrophic cell suspensions were established as an in vitro model to complement the study grape berry photosynthesis. Calli of CSB (Cabernet Sauvignon Berry) cells derived from the inner tissues of the grape berry were sub-cultured in liquid modified MS medium supplemented with 2% sucrose and different hormonal combinations, one auxin (NAA) and three cytokinins (BAP, ZEA and KIN) at two different final concentrations (0.5 and 1 g mL-1). Two different growth light intensities (45- 60 and 80-105 mol m-1 s-1) were also tested. Chlorophyll fluorescence PAM fluorometry was used to evaluate the photochemical efficiency (Fv/Fm) of all suspensions and chlorophyll content was also determined. Results showed that the cytokinin type was crucial to induce the photosynthetic phenotype, but Fv/Fm was low when compared to the value exhibited by grape berry skin. To further study the photoautrophy of the grape berry tissues new callus cultures were established from the exocarp tissues of the fruit, harvested at the green stage (Alvarinho cv). Portions of detached exocarp were cultured on B5 solid medium supplemented with different hormonal combinations (NAA or 2,4-D with BAP or ZEA) at different concentrations (0.1 or 0.2 g mL-1 for auxins and 0.2 or 0.4 g mL-1 for cytokinins). Only two combinations were responsive but both induced pale green calli with higher growth rates. To our knowledge, this is a pioneer study on calli production from the exocarp of the grape berry from the Portuguese variety Alvarinho. This approach opens good perspectives to study in more detail the physiology of these cells, namely the role of photosynthesis on cell growth and metabolite production. Moreover, it will allow to investigate the impact of several environmental factors on fruit photosynthesis, such as temperature, light and water potential.Fundação para a Ciência e a Tecnologia (research project no. PTDC/AGR-ALI/100636/2008

Changes in microphytobenthos fluorescence over a tidal cycle: implications for sampling designs

Intertidal microphytobenthos (MPB) are important primary producers and provide food for herbivores in soft sediments and on rocky shores. Methods of measuring MPB biomass that do not depend on the time of collection relative to the time of day or tidal conditions are important in any studies that need to compare temporal or spatial variation, effects of abiotic factors or activity of grazers. Pulse amplitude modulated (PAM) fluorometry is often used to estimate biomass of MPB because it is a rapid, non-destructive method, but it is not known how measures of fluorescence are altered by changing conditions during a period of low tide. We investigated this experimentally using in situ changes in minimal fluorescence (F) on a rocky shore and on an estuarine mudflat around Sydney (Australia), during low tides. On rocky shores, the time when samples are taken during low tide had little direct influence on measures of fluorescence as long as the substratum is dry. Wetness from wave-splash, seepage from rock pools, run-off, rainfall, etc., had large consequences for any comparisons. On soft sediments, fluorescence was decreased if the sediment dried out, as happens during low-spring tides on particularly hot and dry days. Surface water affected the response of PAM and therefore measurements used to estimate MPB, emphasising the need for care to ensure that representative sampling is done during low tide

Photoinhibition in benthic diatom assemblages under light stress

Microphytobenthos are frequently subjected to light intensities higher than those required to saturate photosynthesis, which consequently can cause photoinhibition. Photosystem II (PSII) protein D1 (the main target of photoinhibition) and xanthophyll cycle pigments were quantified in epipelic benthic diatom assemblages under high irradiance, in the presence of inhibitors and promoters of photoprotection mechanisms. Levels of D1 protein were significantly lower under high irradiance (1 h, 1500 µmol photons m–2 s–1) than under low light (80 µmol photons m–2 s–1), corresponding to a photoinhibition of 22 to 29%. Photoinhibition increased to 44 and 80% in the presence of lincomycin (inhibitor of chloroplast-protein synthesis) and dithiothreitol (inhibitor of the xanthophyll cycle), respectively. High light treatment had no significant effect on D1 protein concentrations in the presence of added glutathione and ascorbate, scavengers of reactive oxygen species (ROS). In contrast, the ROS promoter methylviologen increased photoinhibition to 63%. Under light stress, the functional stability of PSII reaction centres of the studied epipelic benthic diatoms was more dependent on xanthophyll cycle activation than on D1 protein recycling mechanisms, and our results substantiate the role of antioxidants in photoprotection via ROS scavenging.publishe

Polynomials over quaternions and coquaternions: a unified approach

This paper aims to present, in a unified manner, results which are valid on both the algebras of quaternions and coquaternions and, simultaneously, call the attention to the main differences between these two algebras. The rings of one-sided polynomials over each of these algebras are studied and some important differences in what concerns the structure of the set of their zeros are remarked. Examples illustrating this different behavior of the zero-sets of quaternionic and coquaternionic polynomials are also presented.(undefined)info:eu-repo/semantics/publishedVersio

Are cyanobacteria a nearly immortal source of high market value compounds?

BACKGROUND: When the human population increases, so does the need to explore a wider range of feedstocks and biomasses, such as cyanobacteria. However, a deeper understanding of the growth patterns and pigment production is required to support the selection of the most beneficial species and conditions for industrial production. The growth and pigment production (i.e., chlorophyll a and C-phycocyanin) of three cyanobacterium species were evaluated following a three-fold aim. The first goal was to compare among a species commonly selected for exploitation (Arthrospira platensis) and two alternative species (Anabaena cylindrica and Nostoc muscorum). The second goal was analyzing pigment production in the long-term. The last goal involved comparing different methods (spectrophotometry and fluorimetry) to understand whether there is an appropriate proxy of biomass increase and pigment production that can be used for monitoring purposes. RESULTS: All species showed high longevity and proved capable of growing for more than 100 days without any additional supplementation. However, the maximum quantum yield of PS II (Fv /Fm) revealed that their photosynthetic efficiency varied over time with a clear decrease after 2 months. Pigment analysis showed a heterogeneous pattern during the growth periods of all three species that could only be captured by the parameter Fv /Fm, but the pattern was only present for A. cylindrica and N. muscorum in some stages of the culture period. CONCLUSION: N. muscorum was found to be the best chlorophyll a and C-phycocyanin producer, with the production peaking for all species at defined time periods within the growth profile. © 2022 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).publishe