406 research outputs found

    Identificação in vivo de um ponto de controle na síntese do amido em milho normal

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    The effect of 3-phosphoglycerate and inorganic pyrophosphate, known activator and inhibitor from in vitro studies of the enzyme ADPG-pyrophosphorylase, was determined in vivo using starchy-corn. The results suggest that above metabolites do modify the activity of the ADPG-pyrophosphorylase, and indicate that conclusions based on in vitro studies do operate in vivo, providing further evidence that this enzymatic step is an important control point in starch biosynthesis.Para verificar in vivo o efeito do 3-PGA (3-fosfoglicerato ou ácido 3-fosfoglicérico) e do PPi (pirofosfato inorgânico) sobre a atividade da ADPG (adenosina difosfato glicose-pirofosforilase), já demonstrado in vitro atuarem como ativador e inibidor, respectivamente, desta enzima, efetuou-se a aplicação de soluções desses dois metabolitos em espigas de milho normal durante o desenvolvimento dos grãos. A análise do conteúdo em açúcares redutores, sacarose e açúcares solúveis, após a maturação dos grãos, parece ter comprovado in vivo o comportamento in vitro desses dois metabolitos. No tratamento com 3-PGA, o nível da sacarose baixou acentuadamente, assim como o nível dos açúcares solúveis, indicando sua utilização para a síntese do amido, com a velocidade da reação aumentada pela ativação da ADPG-pirofosforilase. No tratamento com PPi, houve aumento do nível dos açúcares redutores, indicando sua não utilização na síntese do amido devido à inibição da ADPG-pirofosforilase, e, também neste tratamento, diminuição do nível da sacarose. A germinação dos grãos ocorrida neste tratamento explicaria a diminuição no nível da sacarose por sua utilização na síntese de poli-holosídios estruturais e não na síntese do amido. Os resultados sugerem que 3-PGA e PPi modificam a atividade da ADPG-pirofosforilase e indicam que as conclusões baseadas em estudos in vitro parecem ser válidas in vivo, comprovando evidências anteriores de que este passo enzimático é um importante ponto de controle na síntese do amido

    Novel insights into the marine phase and river fidelity of anadromous twaite shad Alosa fallax in the UK and Ireland

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    © 2020 The Authors. Aquatic Conservation: Marine and Freshwater Ecosystems published by John Wiley & Sons Ltd Most research on anadromous fishes has been invested in their freshwater life-phases, resulting in a relatively sparse understanding of their spatial ecology during marine life-phases. However, understanding the marine dispersal of anadromous fishes is essential to identify threats and to implement conservation measures that fully encompass their lifecycle. The twaite shad Alosa fallax is an anadromous fish increasingly imperilled across its range due to pollution, harvesting, and impediments to freshwater migration, but little is known about its distribution and movements during its marine life-phase. Here, the application of acoustic telemetry provided novel insights into the coastal dispersal of twaite shad in the UK and Ireland during 2018–2019, and the freshwater entry of individuals during the 2019 spawning season. Of 73 twaite shad acoustic-tagged during their upstream migration in the River Severn in May 2018, 58 emigrated from the river. Twelve were subsequently detected 200 km to the south-west at the Taw–Torridge Estuary between July 2018 and April 2019, where estuarine movements up to 5.8 km inland occurred in summer, winter, and spring. One was subsequently detected in the Munster Blackwater Estuary (Ireland) and then in the River Severn, indicating a minimum movement distance of 950 km. Thirty-four (59%) of the emigrating individuals from 2018 re-entered fresh water in the rivers Severn (n = 33) and Wye (n = 2) in April and May 2019. These results suggest year-round use of estuarine and nearshore habitats by at least a subset of the twaite shad population during their marine phase, providing evidence of potential range overlap between populations that spawn in different areas in the UK and Ireland, which may be facilitated by substantial dispersal. The results also highlight the potential of telemetry for estimating freshwater and marine mortality, and the benefits of sharing detection data across networks

    Draft genome sequence of isolate Staphylococcus aureus LHSKBClinical, isolated from an infected hip

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    We report here the genome sequence of a clinical isolate of <i>Staphylococcus aureus</i> from an orthopedic infection. Phenotypically diverse <i>Staphylococcus aureus</i> strains are associated with orthopedic infections and subsequent implant failure, and some are highly resistant to antibiotics. This genome sequence will support further analyses of strains causing orthopedic infections

    Limits on Cosmological Variation of Strong Interaction and Quark Masses from Big Bang Nucleosynthesis, Cosmic, Laboratory and Oklo Data

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    Recent data on cosmological variation of the electromagnetic fine structure constant from distant quasar (QSO) absorption spectra have inspired a more general discussion of possible variation of other constants. We discuss variation of strong scale and quark masses. We derive the limits on their relative change from (i) primordial Big-Bang Nucleosynthesis (BBN); (ii) Oklo natural nuclear reactor, (iii) quasar absorption spectra, and (iv) laboratory measurements of hyperfine intervals.Comment: 10 pages 2 figurs: second version have several references added and some new comment

    Exciton swapping in a twisted graphene bilayer as a solid-state realization of a two-brane model

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    It is shown that exciton swapping between two graphene sheets may occur under specific conditions. A magnetically tunable optical filter is described to demonstrate this new effect. Mathematically, it is shown that two turbostratic graphene layers can be described as a "noncommutative" two-sheeted (2+1)-spacetime thanks to a formalism previously introduced for the study of braneworlds in high energy physics. The Hamiltonian of the model contains a coupling term connecting the two layers which is similar to the coupling existing between two braneworlds at a quantum level. In the present case, this term is related to a K-K' intervalley coupling. In addition, the experimental observation of this effect could be a way to assess the relevance of some theoretical concepts of the braneworld hypothesis.Comment: 15 pages, 3 figures, final version published in European Physical Journal

    Phenomenology of Λ\Lambda-CDM model: a possibility of accelerating Universe with positive pressure

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    Among various phenomenological Λ\Lambda models, a time-dependent model Λ˙H3\dot \Lambda\sim H^3 is selected here to investigate the Λ\Lambda-CDM cosmology. Using this model the expressions for the time-dependent equation of state parameter ω\omega and other physical parameters are derived. It is shown that in H3H^3 model accelerated expansion of the Universe takes place at negative energy density, but with a positive pressure. It has also been possible to obtain the change of sign of the deceleration parameter qq during cosmic evolution.Comment: 16 Latex pages, 11 figures, Considerable modifications in the text; Accepted in IJT

    The development of videoconference-based support for people living with rare dementias and their carers: Protocol for a 3-phase support group evaluation

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    Background: People living with rarer dementias face considerable difficulty accessing tailored information, advice, and peer and professional support. Web-based meeting platforms offer a critical opportunity to connect with others through shared lived experiences, even if they are geographically dispersed, particularly during the COVID-19 pandemic. Objective: We aim to develop facilitated videoconferencing support groups (VSGs) tailored to people living with or caring for someone with familial or sporadic frontotemporal dementia or young-onset Alzheimer disease, primary progressive aphasia, posterior cortical atrophy, or Lewy body dementia. This paper describes the development, coproduction, field testing, and evaluation plan for these groups. Methods: We describe a 3-phase approach to development. First, information and knowledge were gathered as part of a coproduction process with members of the Rare Dementia Support service. This information, together with literature searches and consultation with experts by experience, clinicians, and academics, shaped the design of the VSGs and session themes. Second, field testing involved 154 Rare Dementia Support members (people living with dementia and carers) participating in 2 rounds of facilitated sessions across 7 themes (health and social care professionals, advance care planning, independence and identity, grief and loss, empowering your identity, couples, and hope and dementia). Third, a detailed evaluation plan for future rounds of VSGs was developed. Results: The development of the small groups program yielded content and structure for 9 themed VSGs (the 7 piloted themes plus a later stages program and creativity club for implementation in rounds 3 and beyond) to be delivered over 4 to 8 sessions. The evaluation plan incorporated a range of quantitative (attendance, demographics, and geography; pre-post well-being ratings and surveys; psycholinguistic analysis of conversation; facial emotion recognition; facilitator ratings; and economic analysis of program delivery) and qualitative (content and thematic analysis) approaches. Pilot data from round 2 groups on the pre-post 3-word surveys indicated an increase in the emotional valence of words selected after the sessions. Conclusions: The involvement of people with lived experience of a rare dementia was critical to the design, development, and delivery of the small virtual support group program, and evaluation of this program will yield convergent data about the impact of tailored support delivered to geographically dispersed communities. This is the first study to design and plan an evaluation of VSGs specifically for people affected by rare dementias, including both people living with a rare dementia and their carers, and the outcome of the evaluation will be hugely beneficial in shaping specific and targeted support, which is often lacking in this population

    Heavy quarkonium: progress, puzzles, and opportunities

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    A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the BB-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations. The plethora of newly-found quarkonium-like states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b}, and b\bar{c} bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hot- and cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K. Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D. Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A. Petrov, P. Robbe, A. Vair
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