12 research outputs found
On exact solutions for quantum particles with spin S= 0, 1/2, 1 and de Sitter event horizon
Exact wave solutions for particles with spin 0, 1/2 and 1 in the static
coordinates of the de Sitter space-time model are examined in detail. Firstly,
for a scalar particle, two pairs of linearly independent solutions are
specified explicitly: running and standing waves. A known algorithm for
calculation of the reflection coefficient on the background of
the de Sitter space-time model is analyzed. It is shown that the determination
of R_{\epsilon j} requires an additional constrain on quantum numbers \epsilon
\rho / \hbar c >> j, where \rho is a curvature radius. When taken into account
of this condition, the R_{\epsilon j} vanishes identically. It is claimed that
the calculation of the reflection coefficient R_{\epsilon j} is not required at
all because there is no barrier in an effective potential curve on the
background of the de Sitter space-time. The same conclusion holds for arbitrary
particles with higher spins, it is demonstrated explicitly with the help of
exact solutions for electromagnetic and Dirac fields.Comment: 30 pages. This paper is an updated and more comprehensive version of
the old paper V.M. Red'kov. On Particle penetrating through de Sitter
horizon. Minsk (1991) 22 pages Deposited in VINITI 30.09.91, 3842 - B9
Requirements for a processing-node quantum repeater on a real-world fiber grid
We numerically study the distribution of entanglement between the Dutch cities of Delft and Eindhoven realized with a processing-node quantum repeater and determine minimal hardware requirements for verifiable blind quantum computation using color centers and trapped ions. Our results are obtained considering restrictions imposed by a real-world fiber grid and using detailed hardware-specific models. By comparing our results to those we would obtain in idealized settings, we show that simplifications lead to a distorted picture of hardware demands, particularly on memory coherence and photon collection. We develop general machinery suitable for studying arbitrary processing-node repeater chains using NetSquid, a discrete-event simulator for quantum networks. This enables us to include time-dependent noise models and simulate repeater protocols with cut-offs, including the required classical control communication. We find minimal hardware requirements by solving an optimization problem using genetic algorithms on a high-performance-computing cluster. Our work provides guidance for further experimental progress, and showcases limitations of studying quantum-repeater requirements in idealized situations.QID/Wehner GroupQID/Elkouss GroupQID/Software GroupQuantum Computer Scienc
Antifungal activity and ultrastructural alterations in Pseudocercospora griseola treated with essential oils Atividade antifúngica e alterações ultraestruturais em Pseudocercospora griseola tratado com óleos essenciais
Pseudocercospora griseola, the etiologic agent of angular leaf spot of common bean (Phaseolus vulgaris), is an important disease in all bean-producing regions worldwide and may cause extremely high yield losses. The control of this disease is made more difficult by the pathogen's genetic variability and the inefficiency of fungicides. In this study, of 26 essential oils tested at different concentrations, 25 demonstrated efficiency in affecting the germination of strains 63-31 and 63-63 of the pathogen, reaching inhibition levels of between 80% and 100%. Cymbopogon citratus and Cymbopogon martinii inhibited conidia germination at all concentrations; Eugenia caryophyllata, Cinnamomum sp., Thymus vulgaris, Matricaria recutita, Cordia verbenacea, Origanum vulgare, Cymbopogon nardus, at 0.1 and 0.5%; and Zingiber officinale, Mentha arvensis, Chamaecyparis pisifera, Lavandula officinalis, Ocimum basilicum, Pimpinella anisum, Ocimum selloi, Baccharis dracunculifolia, Laurus nobilis, Citrus sinensis, Melaleuca alternifolia and Eucalyptus globulus, at 0.5%. The main constituents identified were cinnamaldehyde in Cinnamomum sp.; eugenol in E. caryophyllata; trans-β-farnesene in M. recutita; pulegone in C. verbenacea; thymol in T. vulgaris; geranial and neral in C. citratus, and geraniol in C. martini. Through transmission electron microscopy (TEM), it was verified that C. citratus, C. martini and E. caryophyllata presented direct fungitoxic action on P. griseola, causing severe damage to the cellular ultrastructure of the conidia, invalidating germination. These results indicated that essential oils are a promising alternative strategy for the control of angular leaf spot in bean, representing less risk to human health and the environment.<br>Pseudocercospora griseola, agente etiológico da mancha angular do feijoeiro comum (Phaseolus vulgaris), é uma doença importante nas regiões produtoras de feijão em todo o mundo e pode causar perdas de produtividade extremamente elevados. O controle dessa doença é dificultado pela variabilidade genética do patógeno e da ineficiência de fungicidas. Neste estudo, de 26 óleos essenciais testados em concentrações diferentes, 25 demonstraram eficiência em inibir a germinação das linhagens 63-31 e 63-63 do agente patogênico, atingindo níveis de inibição entre 80% e 100%. Cymbopogon citratus e Cymbopogon martini inibiram a germinação de conídios em todas as concentrações; Eugenia caryophyllata, Cinnamomum sp., Thymus vulgaris, Matricaria recutita, Cordia verbenacea, Origanum vulgare, Cymbopogon nardus, em 0,1 e 0,5%, e Zingiber officinale, Mentha arvensis, Chamaecyparis pisifera, Lavandula officinalis, Ocimum basilicum, Pimpinella anisum, Ocimum selloi, Baccharis dracunculifolia, Laurus nobilis, Citrus sinensis, Melaleuca alternifolia e Eucalyptus globulus, em 0,5%. Os principais constituintes identificados foram cinamaldeído em Cinnamomum sp.; Eugenol em E. caryophyllata; trans-β-farneseno em M. recutita; pulegona em C. verbenacea; timol em T. vulgaris; geranial e neral em C. citratus e geraniol em C. martini. Através de microscopia eletrônica de transmissão (TEM), verificou-se que C. citratus, C. martini e E. caryophyllata apresentaram ação antifúngica direta sobre P. griseola, causando graves danos na ultraestrutura celular dos conídios, invalidando a germinação. Esses resultados indicaram que os óleos essenciais são uma estratégia alternativa promissora para o controle da mancha angular do feijoeiro, o que representa menos risco para a saúde humana e ao ambiente
Preserving accuracy in GenBank
GenBank, the public repository for nucleotide and protein sequences, is a critical resource for molecular biology, evolutionary biology, and ecology. While some attention has been drawn to sequence errors, common annotation errors also reduce the value of this database. In fact, for organisms such as fungi, which are notoriously difficult to identify, up to 20% of DNA sequence records may have erroneous lineage designations in GenBank. Gene function annotation in protein sequence databases is similarly error-prone. Because identity and function of new sequences are often determined by bioinformatic analyses, both types of errors are propagated into new accessions, leading to long-term degradation of the quality of the database. Currently, primary sequence data are annotated by the authors of those data, and can only be reannotated by the same authors. This is inefficient and unsustainable over the long term as authors eventually leave the field. Although it is possible to link third-party databases to GenBank records, this is a short-term solution that has little guarantee of permanence. Similarly, the current third-party annotation option in GenBank (TPA) complicates rather than solves the problem by creating an identical record with a new annotation, while leaving the original record unflagged and unlinked to the new record. Since the origin of public zoological and botanical specimen collections, an open system of cumulative annotation has evolved, whereby the original name is retained, but additional opinion is directly appended and used for filing and retrieval. This was needed as new specimens and analyses allowed for reevaluation of older specimens and the original depositors became unavailable. The time has come for the public sequence database to incorporate a community-curated, cumulative annotation process that allows third parties to improve the annotations of sequences when warranted by published peer-reviewed analyses.Fil: Bidartondo, Martin I.. Imperial College London; Reino Unido. Royal Botanic Gardens; Reino UnidoFil: Bruns, Thomas D.. University of California at Berkeley; Estados UnidosFil: Blackwell, Meredith. Louisiana State University; Estados UnidosFil: Edwards, Ivan. University of Michigan; Estados UnidosFil: Taylor, Andy F. S.. Swedish University of Agricultural Sciences; SueciaFil: Bianchinotti, Maria Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur; ArgentinaFil: Padamsee, Mahajabeen. University of Minnesota; Estados UnidosFil: Callac, Philippe. Institut National de la Recherche Agronomique; FranciaFil: Lima, Nelson. Universidade do Minho; PortugalFil: White, Merlin M.. Boise State University; Estados UnidosFil: Barreau Daly, Camila. Centre National de la Recherche Scientifique; Francia. Institut National de la Recherche Agronomique; FranciaFil: Juncai, M. A.. Chinese Academy of Sciences; República de ChinaFil: Buyck, Bart. Museum National d'Histoire Naturelle; FranciaFil: Rabeler, Richard K.. University of Michigan; Estados UnidosFil: Liles, Mark R.. Auburn University; Estados UnidosFil: Estes, Dwayne. Austin Peay State University; Estados UnidosFil: Carter, Richard. Valdosta State University; Estados UnidosFil: Herr Jr., J. M.. University of South Carolina; Estados UnidosFil: Chandler, Gregory. University of North Carolina; Estados UnidosFil: Kerekes, Jennifer. University of California at Berkeley; Estados UnidosFil: Cruse Sanders, Jennifer. Salem College Herbarium; Estados UnidosFil: Galán Marquez, R.. Universidad de Alcalá; EspañaFil: Horak, Egon. Zurich Herbarium; SuizaFil: Fitzsimons, Michael. University of Chicago; Estados UnidosFil: Döering, Heidi. Royal Botanic Gardens; Reino UnidoFil: Yao, Su. China Center of Industrial Culture Collection; ChinaFil: Hynson, Nicole. University of California at Berkeley; Estados UnidosFil: Ryberg, Martin. University Goteborg; SueciaFil: Arnold, A. E.. University of Arizona; Estados UnidosFil: Hughes, Karen. University of Tennessee; Estados Unido