The genus Gertrudiella broth. (Pottiaceae, Bryophyta) in Paraguay

As part of a study of the bryophytes of South America, some samples collected in Paraguay were identified as Gertrudiella uncinicoma, a species of Pottiaceae characterized by the presence of a well-developed central strand and a thick-walled hyalodermis on the stem, lanceolate leaves, laminal cells ventrally mammillose, and several rows of guides cells at the transverse section of the costae. This work represents the first record of the genus from Paraguay. A complete description, ecological comments, illustrations in optical and scanning electron microscopy, and a distribution map are presented.Fil: Jimenez, Maria Soledad. 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; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: Suarez, Guillermo Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; Argentina. Universidad Nacional de Tucumán; Argentin

Philonotis pomangium (Bartramiaceae, Bryophyta): una adición a la flora briológica de Perú

Philonotis pomangium (Bartramiaceae, Bryophyta): una adición a la flora briológica de Perú. Philonotis pomangium es una especie neotropical registrada para Argentina, Bolivia y Brasil. Se caracteriza por las hojas ovado-lanceoladas, células de la lámina cuadradas hacia la base, papilosas en el ángulo distal, y propágulos presentes (tipo "brood branches"). Durante la revisión del género Philonotis en el sur de Sudamérica, algunos especímenes coleccionados en Perú coinciden con P. pomangium, una especie registrada por primera vez para el país. Adicionalmente, se estudió el ejemplar tipo de Philonotis boliviensis, y se la propone aquí como un nuevo sinónimo de P. pomangium. Se presenta una descripción detallada, fotomicrografías en MO y MEB, comentarios sobre la especie y una tabla comparativa de las especies emparentadas de Philonotis del Perú. La distribución Neotropical de P. pomangium se ilustra en un mapa.Philonotis pomangium is a neotropical species recorded from Argentina, Bolivia and Brazil. It is characterized by the ovate-lanceolate leaves, laminal cell quadrate at the base, papillose at the distal angles, and propagules present (brood branches). During the revision of the genus Philonotis in southern South America some samples collected in Peru agreed with P. pomangium, a species not recorded for the country. In addition, the study of the type specimens of Philonotis boliviensis was performed, and it is proposed as a new synonym of P. pomangium. A description, photomicrographs on OM and SEM, comments on the species, and a comparative table for related Philonotis species of Peru are here presented. The Neotropical distribution of P. pomangium is depicted in a map.Fil: Jimenez, Maria Soledad. 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: Suarez, Guillermo Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; Argentin

Distributed Successive Approximation Coding using Broadcast Advantage: The Two-Encoder Case

Traditional distributed source coding rarely considers the possible link between separate encoders. However, the broadcast nature of wireless communication in sensor networks provides a free gossip mechanism which can be used to simplify encoding/decoding and reduce transmission power. Using this broadcast advantage, we present a new two-encoder scheme which imitates the ping-pong game and has a successive approximation structure. For the quadratic Gaussian case, we prove that this scheme is successively refinable on the {sum-rate, distortion pair} surface, which is characterized by the rate-distortion region of the distributed two-encoder source coding. A potential energy saving over conventional distributed coding is also illustrated. This ping-pong distributed coding idea can be extended to the multiple encoder case and provides the theoretical foundation for a new class of distributed image coding method in wireless scenarios.Comment: In Proceedings of the 48th Annual Allerton Conference on Communication, Control and Computing, University of Illinois, Monticello, IL, September 29 - October 1, 201

Rauiella niveo-calycina es un sinónimo nuevo de R. praelonga

Rauiella niveo-calycina (Müll. Hal) Wijk & Marg. is proposed as a new synonym of R. praelonga (Schimp. ex Besch) Wijk & Marg. The species treated is discussed briefly.Rauiella niveo-calycina es un sinónimo nuevo de R. praelonga. R. niveo-calycina (Müll. Hal) Wijk & Marg. es propuesta en este trabajo como un sinónimo nuevo de R. praelonga (Schimp. ex Besch) Wijk & Marg. La especie tratada es brevemente discutida.Fil: Suarez, Guillermo Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: Schiavone, María M.. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentin

Interactions between Eriosyce villicumensis (Cactaceae) and shrubs: a study case in the hyper arid Monte desert of Argentina

Se estudió la distribución espacial intraespecífica e interespecífica de Eriosyce villicumensis (Rausch) Katt. en tres unidades fisiográficas y a microescala bajo los arbustos. Se analizó la influencia de los arbustos en la radiación fotosintéticamente activa y temperatura del suelo. La distribución intraespecífica de E. villicumensis resultó aleatoria. La distribución interespecífica estuvo asociada con Larrea cuneifolia y/o Zuccagnia punctata, observándose disminución de asociación desde el centro al borde de los arbustos, coincidiendo con los gradientes de luz y temperatura detectados bajo los arbustos. En ambientes desérticos, la interacción entre especies es una estrategia que permite la supervivencia de varias especies.The spatial intraspecific and interspecific distribution of Eriosyce villicumensis (Rausch) Katt. was studied in three physiographic units and at micro-scale under shrubs. The influence of shrubs on photosynthetically active radiation and on soil temperature was analyzed. The intraspecific distribution of E. villicumensis was random. The interspecific distribution was highly associated with Larrea cuneifolia and/or Zuccagnia punctata, observing decreasing association from the centre toward the edge of shrub canopies, coinciding with both the light and temperature gradients detected under those shrubs. In desert environments, the interaction between species is a strategy that allows survival of several plants.Fil: Almiron, Martin Guillermo. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Martinez Carretero, Eduardo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; Argentin

Quality of Life in Buenos Aires Neighborhoods: Hedonic Price Regressions and the Life Satisfaction Approach

This paper studies quality of life in urban neighborhoods in the Buenos Aires Metropolitan Area. First, hedonic price regressions for residential prices are augmented with neighborhood characteristics, based on a real estate database with indicators on each property’s distance to public facilities and amenities, and on a smaller survey with greater detail. Second, following recent developments in the field of happiness research, the document assesses the importance of different neighborhood characteristics on quality of life by interacting objective and subjective indicators. Indices of quality of life related to local amenities are derived for the different neighborhoods for both the hedonic regression and life satisfaction approaches. The results indicate a strong but not perfect correlation between real estate prices, income levels and neighborhood characteristics, suggesting scope for welfare-improving policy interventions.

Physical evolution in Loop Quantum Cosmology: The example of vacuum Bianchi I

We use the vacuum Bianchi I model as an example to investigate the concept of physical evolution in Loop Quantum Cosmology (LQC) in the absence of the massless scalar field which has been used so far in the literature as an internal time. In order to retrieve the system dynamics when no such a suitable clock field is present, we explore different constructions of families of unitarily related partial observables. These observables are parameterized, respectively, by: (i) one of the components of the densitized triad, and (ii) its conjugate momentum; each of them playing the role of an evolution parameter. Exploiting the properties of the considered example, we investigate in detail the domains of applicability of each construction. In both cases the observables possess a neat physical interpretation only in an approximate sense. However, whereas in case (i) such interpretation is reasonably accurate only for a portion of the evolution of the universe, in case (ii) it remains so during all the evolution (at least in the physically interesting cases). The constructed families of observables are next used to describe the evolution of the Bianchi I universe. The performed analysis confirms the robustness of the bounces, also in absence of matter fields, as well as the preservation of the semiclassicality through them. The concept of evolution studied here and the presented construction of observables are applicable to a wide class of models in LQC, including quantizations of the Bianchi I model obtained with other prescriptions for the improved dynamics.Comment: RevTex4, 22 pages, 4 figure

Biased Perceptions of Income Distribution and Preferences for Redistribution: Evidence from a Survey Experiment

Individual perceptions of income distribution play a vital role in political economy and public finance models, yet there is little evidence regarding their origins or accuracy. This study examines how individuals form these perceptions and posits that systematic biases arise from the extrapolation of information extracted from reference groups. A tailored household survey provides original evidence on the significant biases in individuals’ evaluations of their own relative position in the distribution. Furthermore, the data supports the hypothesis that the selection process into the reference groups is the source of those biases. Finally, this study also assesses the practical relevance of these biases by examining their impact on attitudes towards redistributive policies. An experimental design incorporated into the survey provides consistent information on the own ranking within the income distribution to a randomly selected group of respondents. Confronting agents’ biased perceptions with this information has a significant effect on their stated preferences for redistribution. Those who had overestimated their relative position and thought of themselves relatively richer than they were demand higher levels of redistribution when informed of their true ranking. This relationship between biased perceptions and political attitudes provides an alternative explanation for the relatively low degree of redistribution observed in modern democracies.preferences for redistribution, limited information, perceptions of income distribution, field experiment