Anti-deSitter universe dynamics in LQC

A model for a flat isotropic universe with a negative cosmological constant $\Lambda$ and a massless scalar field as sole matter content is studied within the framework of Loop Quantum Cosmology. By application of the methods introduced for the model with $\Lambda=0$, the physical Hilbert space and the set of Dirac observables are constructed. As in that case, the scalar field plays here the role of an emergent time. The properties of the system are found to be similar to those of the $k=1$ FRW model: for small energy densities, the quantum dynamics reproduces the classical one, whereas, due to modifications at near-Planckian densities, the big bang and big crunch singularities are replaced by a quantum bounce connecting deterministically the large semiclassical epochs. Thus in Loop Quantum Cosmology the evolution is qualitatively cyclic.Comment: Revtex4, 29 pages, 20 figures, typos correcte

Neuropatia uditiva: incidenza e caratteristiche cliniche in neonati a rischio

INTRODUZIONE La neuropatia uditiva (NU), entità nosografica di recente individuazione, costituisce un’importante causa di ipoacusia di grado variabile dal lieve al severo, ad insorgenza sia nella primissima infanzia che nell’età giovanile, raramente nell’anziano. È riconducibile ad alterazioni di alcune componenti della via uditiva, tra cui le cellule cocleari ciliate interne (le esterne sono caratteristicamente risparmiate), le loro sinapsi con le fibre afferenti del nervo acustico o il nervo acustico stesso. L’eziologia, fatta eccezione per le forme riconducibili a mutazioni del gene OTOF (codificante per l’otoferlina, una proteina espressa dalle cellule ciliate interne cocleari), è stata posta in relazione con differenti fattori di rischio. In particolare, diversi studi hanno evidenziato una maggiore incidenza di NU tra i neonati ricoverati in UTIN o esposti, in epoca perinatale, a particolari condizioni quali iperbilirubinemia, anossia, patologie infettive, farmaci ~ 239 ~ ototossici. MATERIALI E METODI Dato il caratteristico profilo audiologico la diagnosi necessita della registrazione contemporanea delle OAEs (presenti in quanto integre le cellule ciliate esterne) e delle risposte ABR che risultano alterate, desincronizzate o addirittura irriconoscibili. Si rileva anche l’assenza del riflesso stapediale, sia ipsi che controlateralmente. RISULTATI Il nostro studio ha rilevato, in un campione di 110 bambini ricoverati in UTIN per un periodo > 5 giorni, 15 soggetti con deficit uditivo, tra i quali sono stati individuati 4 casi (26,6%) con profilo audiologico compatibile con diagnosi di NU.Gli autori descrivono le caratteristiche audiologiche ed eziologiche legate a suddetti pazienti paragonando l’incidenza della neuropatia uditiva in UTIN, il grado della sordità, la mono-bilateralità, i fattori di rischio e l’iter riabilitativo più idoneo con i dati riportati in letteratura. CONCLUSIONI La neuropatia uditiva, essendo causa di ipoacusia, può compromettere lo sviluppo del linguaggio e necessita di una diagnosi tempestiva per poter adottare le opportune misure riabilitative. In considerazione della necessità di esecuzione contemporanea di OAEs e dell’ABR ai fini di una corretta diagnosi, oltre che dei costi associati a quest’ultima metodica si raccomanda la valutazione dei potenziali evocati uditivi nei neonati ricoverati in UTIN e nei soggetti esposti a fattori di rischio più frequentemente associati a NU

Seed production of common teasel (Dipsacus fullonum) and response to intraspecific competition in Buenos Aires province, Argentina

Dipsacus fullonum L. (common teasel) is a short-lived perennial plant that has become an invasive weed in Argentina and many other countries. It reduces native species diversity and forage production in natural protected areas and grasslands. Reproduction is only through seeds. Field surveys were carried out to determine reproductive potential under natural populations growing in four different locations of Buenos Aires province, Argentina (Bahía Blanca, Saldungaray, Necochea and Energía). At the onset of flowering, 30 plants were randomly tagged at each location. Selected plants included those considered growing in a group and those growing alone (when no other plant was adjacent for at least 60 cm). Once plant senescence was identified, all heads were counted and harvested individually. A linear regression model that described the relationship between the weight of seeds from a single head and the number of seeds was used to estimate the total seed production of each plant. The number of heads per plant varied from 3 (Energía) to 62 (Bahía Blanca). No differences were detected in the number of seeds in the principal head at the different growth situations. Across growth situations, principal heads from plants growing in Bahía Blanca showed 16%, 12%, and 22% more seeds than Energía, Necochea and Saldungaray, respectively. Total seed production per plant ranged from 1,485 (Energía) to 15,551 (Bahía Blanca). Plants growing in Bahía Blanca produced a number of heads and seeds higher than the other evaluated locations. Plants growing alone showed 46% and 48% greater head production and seed production across locations than plants in groups, respectively. This high production potential of common teasel plants growing alone would encourage the invasion of new areas, when compared with plants growing in dense patches.Dipsacus fullonum L. (carda silvestre) es una especie perenne de vida corta considerada una maleza invasora en Argentina y en varios otros países. La carda silvestre compite con especies nativas en los sitios que invade reduciendo la diversidad florística en áreas protegidas y la disponibilidad de forraje en pastizales naturales. Su modo de reproducción es únicamente a través de semillas. El objetivo de este trabajo fue determinar el potencial reproductivo y el efecto de la competencia intraespecífica sobre este mismo parámetro, en poblaciones naturales de carda creciendo en cuatro localidades diferentes de la provincia de Buenos Aires, Argentina (Bahía Blanca, Saldungaray, Necochea y Energía). Al inicio de la floración, se marcaron 30 plantas al azar en cada población. Las plantas se seleccionaron incluyendo aquellas creciendo en grupos y creciendo aisladas (cuando ninguna otra planta de carda se encontraba creciendo dentro de un radio de al menos 60 cm). Una vez identificada la senescencia de la planta, todas las inflorescencias (capítulos) fueron cosechadas individualmente. Se utilizó un modelo de regresión lineal para describir la relación entre el peso de semillas de un solo capítulo y el número de semillas, con el objetivo de estimar la producción total de semillas de cada planta. El número de capítulos por planta varió entre 3 (Energía) y 62 (Bahía Blanca). No se detectaron diferencias en el número de semillas del capítulo principal en las diferentes condiciones de crecimiento. El capítulo principal de las plantas que se encontraban creciendo en Bahía Blanca mostró un número de semillas 16%, 12% y 22% más alto que Energía, Necochea y Saldungaray, respectivamente. La producción total de semillas registrada por planta osciló entre 1.485 (Energía) y 15.551 (Bahía Blanca). Las plantas que se encontraban creciendo en Bahía Blanca produjeron un mayor número de capítulos y semillas que el resto de las localidades. Las plantas que crecieron aisladas mostraron un 46% y un 48% más de producción de capítulos y semillas en todas las localidades censadas que las plantas en grupos, respectivamente. Este alto potencial de producción de semillas, en plantas de carda silvestre creciendo aisladas, fomentaría la invasión de nuevas áreas, en comparación con plantas que se encuentran creciendo en parches densos.Gerencia de Contenidos Periodísticos y Editoriales, DNACI, INTAFil: Daddario, Juan Facundo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiarida; ArgentinaFil: Daddario, Juan Facundo. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiarida; ArgentinaFil: Daddario, Juan Facundo. Universidad Nacional del Sur. Departamento de Agronomía; Argentina.Fil: Tucat, Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiarida; ArgentinaFil: Tucat, Guillermo. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiarida; ArgentinaFil: Fernández, Osvaldo A. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Bentivegna, Diego Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiarida; ArgentinaFil: Bentivegna, Diego Javier. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiarida; Argentin

MODERNIZATION OF THE TRADING AND LOGISTIC SYSTEM OF THE FRUIT AND VEGETABLE SECTOR OF CHUBUT PROVINCE, PATAGONIA

The Valle Inferior del Río Chubut (VIRCH) is the main valley irrigated of Patagonia –Argentina- with 23,000 hectares (69,000 acres) where, after livestock, the vegetable and fruit production has gained second place in importance because of its localization underneath the Barrier of Animal and Plant Health of Rio Colorado, which makes the products safer since it is used much less agrochemicals, and consequently offers higher quality and less perishable, although the valley production do not cover local consumption. Because of that, the Provincial Government with the National Government’s technical support created a Program denominated "Development and Strengthening of an Agrifood Platform for fruit and vegetable in Chubut Province", counting with local and international financing. This proposal tries to ensure the provision or supply of fruits and vegetables to local consumers for which requires infrastructure and adequate tools to improve transparency of commercial transactions. In the meantime, to transforming the system of wholesale marketing it is required the construction of a platform as a place of development of new services companies and improvement the current ones. This Unit will be a right marketplace for buying wholesale horticultural products coming from other markets outside the region and for stimulates consumption through the implementation of food safety and quality control among other advantages such as fair prices. The main purpose is to analyze modernization of the Trading System and Logistics for fruits and vegetables of the province of Chubut