22,725 research outputs found
Chlorotic mottle of bean (Phaseolus vulgaris L.)
No full textFor the past years there have been outbreaks of a disease of bean ( Phaseolus vulgaris L.) in Colombia called bean chlorotic mottle. The etiology of bean chlorotic mottle was not known, but the disease was generally believed to be incited by the same whitefly-transmitted virus that causes variegation in malvaceous plants. The aim of this study was to identify and further characterize the causal agent of bean chlorotic mottle.As from the literature it was not clear which symptoms were characteristic of the disease, firstly a symptom had to be established common to all allegedly bean chlorotic mottle-affected bean plants. This symptom, a sharp mosaic in which the discoloured areas ranged from pale greenish-yellow to bright yellow, was of diagnostic value to detect infected plants in the field. In addition to this sharp mosaic, chlorotic mottle-affected bean plants in the field often showed a host of other symptoms, such as mild mottle, rugosity, leaf curling, malformation, dwarfing, proliferation and witches' broom-like growth. In the same affected population some bean plants showed only the sharp mosaic, whereas others showed additional witches' broom-like growth.Mechanical inoculation experiments conducted with crude sap and partially purified preparations from bean plants exhibiting chlorotic mottle in the field, showed three viruses to be present, viz. bean mild mosaic virus, cucumber mosaic virus and southern bean mosaic virus. By means of differential hosts these three viruses could be separated. Isolates of these viruses were designated BMMV-CIAT, CMV-CIAT and SBMV-CIAT, respectively. Experiments conducted with whiteflies did not reveal the presence of any whitefly-transmitted virus in chlorotic mottle-affected bean plants.BMMV-CIAT, is an isometric particle, 32 nm in diameter, with a single-stranded RNA molecule. The virus is readily transmitted mechanically and its host range is restricted to legumes, viz. Glycine max , Macroptilium spp., Phaseolus spp. and Rhynchosia minima . In P. vulgaris the virus usually causes a mild mosaic which is hardly visible, and in certain cultivars with age, the virus becomes latent. Though affected bean plants grew normally producing healthy- looking pods, flowering and pod formation were usually delayed by about a week under glasshouse conditions. The chrysomelid beetles Diabrotica balteata and Cerotoma facialis were efficient vectors of BMMV-CIAT. The virus is seed-transmitted in beans, percentages ranging from 1.2 to 3.6 in the different cultivars tested. In contrast to many other beetle-transmitted viruses, BMMV-CIAT sediments in sucrose gradients as one particle. The physical and chemical properties of BMMV-CIAT are similar or equal to those of BMMV described by Waterworth et al. (1977). The darkly stained granular material in root cells occasionally observed in the light microscope, proved to be aggregates of virus particles.Cross protection and serological tests showed that CMV-CIAT is related to the CMV-type strain. However, many differences exist between them, the most striking being the ability of CMV-CIAT to cause systemic mosaic in P. vulgaris . The host reactions of CMV- CIAT resembled those of CMV-B 32, an isolate from bean in Spain (Bos and Maat, 1974), but the former had a longer longevity in vitro . Generally, CMV-CIAT induced a yellow mosaic in P. vulgaris , but the symptoms varied greatly in different cultivars. In the cultivars Honduras 46 and Porrillo 1 a sharp mosaic, similar to chlorotic mottle, was produced one month after inoculation with CMV-CIAT None of the bean cultivars and CIAT advanced breeding lines tested were found to be resistant or hypersensitive to CMV-CIAT The virus is transmitted by Aphis gossypii and through seeds of P. vulgaris , Vigna radiata and V. unguiculata 'California Blackeye'. It has poor antigenic properties and is serologically related to CMV-B 32, to a CMV isolate from Yucca (Bouwen et al., 1978) and to the Y-strain of CMV (Scott, 1968). Large inclusions in plant tissues infected with CMV-CIAT could easily be detected in the light microscope.The third virus, SBMV-CIAT, is readily transmitted mechanically. Though the host plant range included mostly legumes, the virus also infected Cucumis sativus 'Ashley'. The virus was more harmful to P. acutifolius , in which it caused severe top necrosis, than to P. vulgaris . Among the cultivars and CIAT advanced breeding lines of P. vulgaris , hypersensitive hosts were found. The virus induced a bright yellow mosaic in G. max . Besides P. vulgaris 'Pinto U.I. 650' other suitable assay hosts for SBMV-CIAT were found viz. Mucuna pruriens and M. utilis which reacted with pin-point necrotic local lesions to the virus. SBMV-CIAT is seed transmitted, the percentages ranging from 3.6 to 33.6 depending on the bean cultivar. Thephysical and chemical properties of SBMV-CIAT are similar or equal to the SBMV bean strain, except for the guanine content of the nucleic acid.An experiment conducted to find out the effect of the above- mentioned viruses alone or in combination with each other on bean plants, indicated that symptoms resembling chlorotic mottle could be reproduced in bean plants by mechanical inoculation with CMV-CIAT alone or in combination with the other two viruses. The vast range of other symptoms sometimes exhibited by bean plants with chlorotic mottle in the field, could also be reproduced by mechanically inoculating the viruses in different combinations at different times after planting of seeds. Witches' broom-like symptoms were produced in bean plants inoculated on their primary leaves with a mixture containing SBMV-CIAT with BMMV-CIAT or with CMV-CIATFrom the present study it is clear that bean chlorotic mottle, as described in literature, is a composite disease caused by a combination of BMMV-CIAT, CMV-CIAT and SBMV-CIAT in which CMV-CIAT is responsible for the sharp mosaic and the other two viruses together are responsible for the additional symptoms like rugosity, leaf curling, witches' broom-like growth etc. Efficient vectors of these viruses are present in the bean fields. Though data are not available for the population distribution of aphids, chrysomelid beetles are present throughout the year in the CIAT fields. Seed transmission of the virus is of considerable epidemiological significance. Infected seeds are vehicles for long distance transport and survival from one season to another, especially in case of BMMV-CIAT, and BMMV-CIAT which have a narrow host range. The diseases caused by the three viruses might be controlled by reducing the number of infection sources and by limiting the spread of the viruses
The generalized Liénard polynomial differential systems x'=y,y'= -g(x) - f (x)y with deg g = deg f 1 are not Liouvillian integrable
No full textAgraïments: The second author was supported by Portuguese National Funds through FCT - Fundação para a Ciência e a Tecnologia within the project PTDC/MAT/117106/2010 and by CAMGSD (PEst-OE/EEI/LA0009/2013)We prove the nonexistence of Liouvillian first integrals for the generalized Li\'enard polynomial differential systems of the form x' = y, y'=-g(x)-f(x)y, where g(x) and f(x) are arbitrary polynomials such that g = f 1
Pensar la violencia desde G. Deleuze
No full textEl artículo reflexiona sobre el fenómeno de la violencia en nuestras sociedades tardomodernas. En primer lugar, critica la concepción ilustrada de la violencia, según la cual ésta es siempre una desviación de la razón, es decir, una "sinrazón". En segundo lugar, el autor sostiene que la comprensión de la violencia debe hacerse desde el "pensamiento de la diferencia". Desde esta última perspectiva, la violencia es el resultado del imperio de la "lógica oposicional" o "lógica binaria", la cual sustituye a la relación diferencial de carácter rizomático. Se recurre, fundamentalmente, al pensamiento de G. Deleuze, matizando el fenómeno de la violencia como "necedad", "geometría de Estado" e "incapacidad para ser afectado".The article reflects on the phenomenon of violence in our late modern societies. First, criticizes the Enlightenment conception of violence, that it is always a deviation of reason, ie a "unreason". Secondly, the author argues that the understanding of violence must be from the "thought of difference". From the latter perspective, violence is the result of the rule of "oppositional logic" or "binary logic" which replaces the differential relation of rhizomatic character. It basically resorts to thoughts of G. Deleuze, qualifying the phenomenon of violence as "stupidity", "geometry of State" and "incapacity to be affected"
Cooling rates of neutron stars and the young neutron star in the Cassiopeia A supernova remnant
No full textWe explore the thermal state of the neutron star in the Cassiopeia A supernova remnant using the recent result of Ho & Heinke that the thermal radiation of this star is well described by a carbon atmosphere model and the emission comes from the entire stellar surface. Starting from neutron star cooling theory, we formulate a robust method to extract neutrino cooling rates of thermally relaxed stars at the neutrino cooling stage from observations of thermal surface radiation. We show how to compare these rates with the rates of standard candles – stars with non-superfluid nucleon cores cooling slowly via the modified Urca process. We find that the internal temperature of standard candles is a well-defined function of the stellar compactness parameter x=rg/R, irrespective of the equation of state of neutron star matter (R and rg are circumferential and gravitational radii, respectively). We demonstrate that the data on the Cassiopeia A neutron star can be explained in terms of three parameters: f?, the neutrino cooling efficiency with respect to the standard candle; the compactness x; and the amount of light elements in the heat-blanketing envelope. For an ordinary (iron) heat-blanketing envelope or a low-mass (? 10?13 M?) carbon envelope, we find the efficiency f?? 1 (standard cooling) for x? 0.5 and f?? 0.02 (slower cooling) for a maximum compactness x? 0.7. A heat blanket containing the maximum mass (?10?8 M?) of light elements increases f? by a factor of 50. We also examine the (unlikely) possibility that the star is still thermally non-relaxe
Flow behaviour of dielectric liquids in an electric field
No full textA family of 10 silicone oils with electrical conductivity similar to 10(-13) S m(-1) (a regime hitherto systematically unexplored) and viscosities ranging from 1 to 2000mPas have been Subjected to an electrical field of up to 1.5kV mm(-1) during flow from a needle. The flow behaviour of these liquids is investigated experimentally in the flow rate regime 10(-8)-10(-12) m(3) s(-1) and we analyse the results using the Ohnesorge number. Due to the low electrical conductivity and high electrical relaxation time of the silicone oils, only unsteady transient jets were found. The onset of this type of jetting has been defined using current measurements and, in contrast to conducting liquids, the non-dimensional jet diameter increases with increase in Ohnesorge number. The time elapsed between the start and finish of jetting increases with increasing Ohnesorge number
Overview of the Author Profiling Task at PAN 2013
No full text[EN] This overview presents the framework and results for the Author Profiling
task at PAN 2013. We describe in detail the corpus and its characteristics,
and the evaluation framework we used to measure the participants performance to
solve the problem of identifying age and gender from anonymous texts. Finally,
the approaches of the 21 participants and their results are described.The author profiling task @PAN-2013 was an activity of the WIQ-EI IRSES project (Grant No. 269180) within the FP 7 Marie Curie People Framework of the European Commission. We want to thank the Forensic Lab of the Universitat Pompeu Fabra Barcelona for sponsoring the award for the winner team. The work of the first author was partially funded by Autoritas Consulting SA and by Ministerio de Economía y Competitividad de España under grant ECOPORTUNITY IPT-2012-1220-430000. The work of the second author was in the framework the DIANA-APPLICATIONS-Finding Hidden Knowledge in Texts: Applications (TIN2012-38603-C02-01) project, and the VLC/CAMPUS Microcluster on Multimodal Interaction in Intelligent Systems. The work of fifth author was funded in part by the Swiss National Science Foundation (SNF) project "Mining Conversational Content for Topic Modelling and Author Identification (ChatMiner)" under grant number 200021_130208.Rangel, F.; Rosso, P.; Koppel, M.; Stamatatos, E.; Inches, G. (2013). Overview of the Author Profiling Task at PAN 2013. CLEF Conference on Multilingual and Multimodal Information Access Evaluation. 352-365. https://riunet.upv.es/handle/10251/46636S35236
G-Drazin inverse combined with inner inverse
No full text[EN] This article introduces new classes of generalized inverses for square matrices named GD1, and the dual, called 1GD inverse. In addition, we discuss a few characterizations and representations of these inverses. The explicit expressions of these inverses have been established via core-nilpotent decomposition. Further, we introduce a binary relation for GD1 inverse and 1GD inverse, along with a few derived properties.The second author is partially supported by the Science & Engineering Research Board (SERB),Govt. of India [grant ID SUR/2022/004357]. The third author was partially supported by the Universidad Nacional de Rio Cuarto [grant PPI 18/C559], Universidad Nacional de La Pampa, Facultadde Ingenieria [grant resol. nro. 135/19], Universidad Nacional del Sur [grant PGI 24/L108], and Ministerio de Economia, Industria y Competitividad (Spain) [grant red de excelencia RED2022-134176-T].Maharana, G.; Sahoo, JK.; Thome, N. (2024). G-Drazin inverse combined with inner inverse. Linear and Multilinear Algebra. https://doi.org/10.1080/03081087.2024.2316786
The generalized Liénard polynomial differential systems x'=y,y'= -g(x) - f (x)y with deg g = deg f 1 are not Liouvillian integrable
No full textAgraïments: The second author was supported by Portuguese National Funds through FCT - Fundação para a Ciência e a Tecnologia within the project PTDC/MAT/117106/2010 and by CAMGSD (PEst-OE/EEI/LA0009/2013)We prove the nonexistence of Liouvillian first integrals for the generalized Li\'enard polynomial differential systems of the form x' = y, y'=-g(x)-f(x)y, where g(x) and f(x) are arbitrary polynomials such that g = f 1
High-resolution numerical analysis of turbulent flow in straight open ducts with rectangular cross-section
No full textTurbulent secondary flow in straight open ducts with rectangular cross-section are studied numerically by means of pseudo- spectral direct numerical simulation (DNS). Similarly to the corresponding closed duct flows, the mean streamwise vorticity pattern in turbulent open duct flows were found to be the statistical footprint of the most probable locations of the quasi-streamwise vortices. A major difference between the two configurations was found in the vicinity of mixed-boundary corners where noticeably persistent vortical structures exist.Turbulent secondary flow in straight open ducts with rectangular cross-section are studied numerically by means of pseudo- spectral direct numerical simulation (DNS). Similarly to the corresponding closed duct flows, the mean streamwise vorticity pattern in turbulent open duct flows were found to be the statistical footprint of the most probable locations of the quasi-streamwise vortices. A major difference between the two configurations was found in the vicinity of mixed-boundary corners where noticeably persistent vortical structures exist
Galdós, el periodismo y la escritura. Reflexiones a partir del cuento "El artículo de fondo"
No full textGaldós was experiencing in his formation and in his first stage of production the narrative space of the press. The short story “El artículo de fondo” was published in 1871 in Revista de España, in 1879, in three installments in El Océano and reappears in 1889 in a collection of brief narrative texts that accompany his Torquemada en la hoguera. This study tries to focus, on the one hand, the variants introduced by the author, especially in the last edition, in order to evaluate the process of maturation of galdosian writing. On the other hand, taking into account the essentially heterotextual consistency of this short story, it try to put it in relation to the pluritextual narrative texture, which the newspaper macrotexts emblematically reflects.Galdós da a conocer por primera vez el cuento “El artículo de fondo” en 1871 en la publicación periódica Revista de España (XIX, 3, 427-440). Bastante años después, volverá a editarlo en una colección de textos de narrativa breve que acompañan su Torquemada en la hoguera (Madrid, La Guirnalda y Episodios y Episodios Nacionales, 1889), advirtiendo a su amigo Clarín en una carta que las «antiguallas» que presentaba el volumen, sacadas del olvido por voluntad ajena al autor, no merecían la pena de una lectura. Sin embargo, Galdós tuvo que empeñarse en la revisión, por lo menos del texto que aquí nos interesa, si consideramos las variantes introducidas, las elisiones y las ampliaciones que la segunda edición del cuento presenta ya sólo a través de una rápida collatio y a partir del incipit. Siguiendo esta pista, no mencionada en los escasos estudios que la crítica galdosiana ha dedicado a “El artículo de fondo” y que hemos podidos consultar, y enfocando la consistencia esencialmente heterotextual del cuento, se ha ido hilvanando una serie de reflexiones acerca del interés de Galdós por los procesos de construcción del texto, del tejido narrativo pluritextual, conjunto de piezas da variada naturaleza verbal y genérica, que el macrotexto del periódico emblemáticamente refleja. Galdós iba experimentando en su formación y en su primera etapa de producción precisamente el espacio narrativo de la prensa, instalado en lo sustancial de la narración diversificada por registros y dispositivos informativos, entre los cuales los visuales, de la actualidad. De ahí, la hipótesis de este estudio que intenta enfocar, más allá de la incontrovertible parodia del periodista costumbrista o serial que el cuento elige come sujeto, las estrategias de trasvase de la realidad en el texto, una realidad siempre multifacética que necesita la yuxtaposición de piezas verbales y de perspectivas singulares, según los rasgos del discurso periodístico y del periódico como sistema textual complejo
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