Bilocal Dynamics for Self-Avoiding Walks

We introduce several bilocal algorithms for lattice self-avoiding walks that provide reasonable models for the physical kinetics of polymers in the absence of hydrodynamic effects. We discuss their ergodicity in different confined geometries, for instance in strips and in slabs. A short discussion of the dynamical properties in the absence of interactions is given.Comment: 38 LaTeX2e pages with 9 postscript figure

The bright optical companion to the eclipsing millisecond pulsar in NGC 6397

We report the possible optical identification of the companion to the eclipsing millisecond pulsar PSR J1740-5340 in the globular cluster NGC 6397. A bright variable star with an anomalous red colour and optical variability which nicely correlates to the orbital period of the pulsar has been found close to the pulsar position. If confirmed, the optical light curve, reminiscent of tidal distorsions similar to those observed in detached and contact binaries, support the idea that this is the first case of a Roche lobe filling companion to a millisecond pulsar.Comment: 9 pages, 4 embedded figures, submitted to ApJ Letter

Nuevos registros de microlíquenes para el norte de Argentina

Se presentan nuevos registros de microlíquenes para el norte de Argentina. Se incluyen comentarios de los siguientes taxones: Coniocarpon cinnabarinum (Arthoniaceae); Schistophoron tenue (Graphidaceae); Reimnitzia santensis (Thelotremataceae); Phyllopeltula steppae (Peltulaceae); Dichosporidium nigrocinctum, Enterographa pallidella y Syncesia effusa (Roccellaceae) y Tylophoron crassiusculum (Caliciales, incertae sedis).New records from Northern Argentina are here presented. Comments about the following taxa are included: Coniocarpon cinnabarinum (Arthoniaceae); Schistophoron tenue (Graphidaceae); Reimnitzia santensis (Thelotremataceae); Phyllopeltula steppae (Peltulaceae); Dichosporidium nigrocinctum, Enterographa pallidella y Syncesia effusa (Roccellaceae) y Tylophoron crassiusculum (Caliciales, incertae sedis).Fil: Michlig, Silvia Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Instituto de Botánica del Nordeste (i); ArgentinaFil: Ferraro, Lidia Itati. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Instituto de Botánica del Nordeste (i); Argentin

The first record of Parmotrema pseudocrinitum (Parmeliaceae, lichenized Ascomycota) in South America

Parmotrema pseudocrinitum is reported for the first time in South America, from northern Argentina. A description of this species and comparisons with related species are presented. A key to species of Parmotrema with ciliate isidia and maps of their distribution are included.Fil: Michlig, Silvia Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Instituto de Botánica del Nordeste (i); ArgentinaFil: Ferraro, Lidia Itati. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Instituto de Botánica del Nordeste (i); Argentin

HST absolute Proper Motions of NGC 6681 (M70) and the Sagittarius Dwarf Spheroidal Galaxy

We have measured absolute proper motions for the three populations intercepted in the direction of the Galactic globular cluster NGC 6681: the cluster itself, the Sagittarius dwarf spheroidal galaxy and the field. For this we used Hubble Space Telescope ACS/WFC and WFC3/UVIS optical imaging data separated by a temporal baseline of 5.464 years. Five background galaxies were used to determine the zero point of the absolute-motion reference frame. The resulting absolute proper motion of NGC 6681 is ($\mu_{\alpha}\cos\delta, \mu_{\delta}$)=($1.58\pm0.18, -4.57\pm0.16$) \masyr. This is the first estimate ever made for this cluster. For the Sgr dSph we obtain ($\mu_{\alpha}\cos\delta, \mu_{\delta})=(-2.54\pm0.18, -1.19\pm0.16$) \masyr, consistent with previous measurements and with the values predicted by theoretical models. The absolute proper motion of the Galaxy population in our field of view is ($\mu_{\alpha}\cos\delta, \mu_{\delta})=(-1.21\pm0.27, -4.39\pm0.26$) \masyr. In this study we also use background Sagittarius Dwarf Spheroidal stars to determine the rotation of the globular cluster in the plane of the sky and find that NGC 6681 is not rotating significantly:\ $v_{\rm rot}=0.82\pm1.02$ km$\,$s$^{-1}$ at a distance of 1 arcmin from the cluster center.Comment: 14 pages, 7 figures, accepted for publication by Ap

Diversidad de macrolíquenes del Parque Nacional Mburucuyá (Corrientes, Argentina)

Se presenta un estudio de los macrolíquenes presentes en el Parque Nacional Mburucuyá (Corrientes, Argentina). Se identificaron cuarenta y nueve especies pertenecientes a quince géneros. Se registran por primera vez para la Argentina Physcia krogiae Moberg, Bulbothrix regnelliana Jungbluth, Marcelli & Elix y Bulbothrix viatica Spielmann & Marcelli, y se amplía el área de distribución de diez especies. Se actualiza la distribución geográfica dentro del país de las especies estudiadas y se incluyen claves para la identificación de los géneros y especies.Macrolichen diversity in Mburucuyá National Park (Corrientes, Argentina). A study of the macrolichens from Mburucuyá National Park (Corrientes, Argentina) is presented. Forty nine species belonging to fifteen genera were identified. Physcia krogiae Moberg, Bulbothrix regnelliana Jungbluth, Marcelli & Elix, and Bulbothrix viatica Spielmann & Marcelli are recorded for the first time in Argentina and the distribution area of ten species is extended. The geographic distribution in the country is actualized and a key for the identification of the genera and species is included.Fil: Michlig, Silvia Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Ferraro, Lidia Itati. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; Argentin

New species and additional records of Coenogonium (Ostropales : Coenogoniaceae) from southern South America

Four new species of lichenized fungi from northern Argentina are described and illustrated: Coenogonium albomarginatum Michlig & L. I. Ferraro, C. brasiliense L. I. Ferraro & Michlig, C. flavovirens L. I. Ferraro & Michlig, and C. verrucosum Michlig & L. I. Ferraro. In addition, C. isidiatum (G. Thor & Vezda) Lücking et al., C. magdalenae Rivas Plata, Lücking & Lizano, C. persistens (Malme) Lücking et al., C. pusillum (Mont.) Lücking et al., and C. weberi (Vezda) Lücking et al. are recorded for the first time from South America. The known distribution of 24 species of this lichen genus is extended. A revision of the genus in Argentina and Paraguay is also presented.Fil: Ferraro, Lidia Itati. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Instituto de Botánica del Nordeste (i); Argentina;Fil: Michlig, Silvia Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Instituto de Botánica del Nordeste (i); Argentina

Normal form decomposition for Gaussian-to-Gaussian superoperators

In this paper we explore the set of linear maps sending the set of quantum Gaussian states into itself. These maps are in general not positive, a feature which can be exploited as a test to check whether a given quantum state belongs to the convex hull of Gaussian states (if one of the considered maps sends it into a non positive operator, the above state is certified not to belong to the set). Generalizing a result known to be valid under the assumption of complete positivity, we provide a characterization of these Gaussian-to-Gaussian (not necessarily positive) superoperators in terms of their action on the characteristic function of the inputs. For the special case of one-mode mappings we also show that any Gaussian-to-Gaussian superoperator can be expressed as a concatenation of a phase-space dilatation, followed by the action of a completely positive Gaussian channel, possibly composed with a transposition. While a similar decomposition is shown to fail in the multi-mode scenario, we prove that it still holds at least under the further hypothesis of homogeneous action on the covariance matrix