658 research outputs found

    Dynamical phase transition of a 1D transport process including death

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    Motivated by biological aspects related to fungus growth, we consider the competition of growth and corrosion. We study a modification of the totally asymmetric exclusion process, including the probabilities of injection α\alpha and death of the last particle δ\delta. The system presents a phase transition at δc(α)\delta_c(\alpha), where the average position of the last particle grows as t\sqrt{t}. For δ>δc\delta>\delta_c, a non equilibrium stationary state exists while for δ<δc\delta<\delta_c the asymptotic state presents a low density and max current phases. We discuss the scaling of the density and current profiles for parallel and sequential updates.Comment: 4 pages, 5 figure

    Circular Bedforms Due to Pit Foraging of Greater Flamingo Phoenicopterus roseus in a Back-barrier Intertidal Habitat

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    The Greater Flamingo Phoenicopterus roseus is known as an ecosystem engineer, rearranging sediment in peculiar bedforms as a consequence of its filter-feeding behaviour. In recent decades, the populations of the Greater Flamingo have notably increased, and now the species is one of the most abundant waterbirds in Mediterranean wetlands. Owing to its range expansion, it inhabits and exploits new and suitable foraging sites detectable by foraging structures left on the sediment. There are few images of the foraging morphologies in the literature, possibly due to their ephemeral nature and difficulty in detecting them. In this manuscript, we present a very detailed UAV (Unmanned Aerial Vehicle) image of an aggregate of pit foraging structures of Greater Flamingo discovered on a back-barrier washover fan in the Marano and Grado Lagoon (Northern Adriatic, Italy)

    Management of post-intubation tracheal stenoses using the endoscopic approach

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    Background and Aim. Tracheal stenosis is a common complication of intubation with or without subsequent tracheotomy whose management remains poorly defined. Over 600 post-intubation tracheal stenoses have been treated in our centre since 1982: the aim of this study was to determine the safety and efficacy of our endoscopic approach. Methods. This retrospective study includes 113 new cases treated between 1998 and 2001. We chose this period to have a standardised technique and a significant number of cases with a sufficiently long follow up (28-78 months). Forty patients who did not meet the criteria for “true stenosis” (granulomas, pseudoglottic stenosis, etc.) were excluded from the study. Results. 73 patients (50±21 years) entered the study: 13 (18%) web-like and 60 (82%) complex stenoses. Most web-like stenoses were successfully treated with Laser Assisted Mechanical Dilation (LAMD) alone; among complex stenoses LAMD was sufficient to treat 13 patients (22%), whereas 47 patients (78%) required stent placement: 22 had their stent removed after one year and did not require any further therapy, 13 inoperable patients required permanent stent and 12 were referred to surgery after failure of multiple endoscopic treatments. No permanent complications secondary to endoscopic treatment were observed. 48 patients (66%) obtained a stable, good result with the endoscopic procedure, 13 (18%) required a permanent stent while 12 patients (16%) were referred to surgery. Conclusions. Our results indicate that the endoscopic treatment of post-intubation tracheal stenoses performed in an expert setting can be considered a safe first-line therapy, leaving some selected cases and the relapsing stenoses, for surgical resection

    Small world effects in evolution

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    For asexual organisms point mutations correspond to local displacements in the genotypic space, while other genotypic rearrangements represent long-range jumps. We investigate the spreading properties of an initially homogeneous population in a flat fitness landscape, and the equilibrium properties on a smooth fitness landscape. We show that a small-world effect is present: even a small fraction of quenched long-range jumps makes the results indistinguishable from those obtained by assuming all mutations equiprobable. Moreover, we find that the equilibrium distribution is a Boltzmann one, in which the fitness plays the role of an energy, and mutations that of a temperature.Comment: 13 pages and 5 figures. New revised versio

    Archeologia delle alte quote sulla montagna veneta: la campagna di ricognizione di superficie 2019 a Recoaro Terme (Vicenza)

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    In this paper we present the preliminary results of the 2019 field survey conducted in the framework of the project “Beyond the border. Study and enhancement of the highlands between Veneto and Trentino”. The aim of this overarching project, which applies a multidisciplinary approach, is threefold: to detect in this mountain landscape the main activity areas and reconstruct possible connections between them; to analyse the long-term relationships between Trentino and Prealpine Veneto from prehistory to the present day; and to study the evolving function of this frontier area during periods of conflict/interaction. Several methods were employed to shed light on the above-mentioned research aims: field-walking survey, analysis of aerial photos, ethnographic and archival research, GIS-based landscape analysis and predictive modelling, and LiDAR data for feature detection in wooded areas. The combined use of all these approaches allowed us to identify long-term exploitation activities, which are documented also by both the ethnographic and archaeological data. The major periods of conflict in these areas are also highlighted in the archaeological record. The 2019-survey campaign opens up new research directions such as the future excavation of Bronze Age occupation zones; network and connectivity analysis between Prealpine Veneto and Trentino; hillforts and their interaction with the highlands. Digital ArchaeologyClassical & Mediterranean ArchaeologyEuropean Prehistor

    Synaptic Integration of Adult-Born Hippocampal Neurons Is Locally Controlled by Astrocytes.

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    Adult neurogenesis is regulated by the neurogenic niche, through mechanisms that remain poorly defined. Here, we investigated whether niche-constituting astrocytes influence the maturation of adult-born hippocampal neurons using two independent transgenic approaches to block vesicular release from astrocytes. In these models, adult-born neurons but not mature neurons showed reduced glutamatergic synaptic input and dendritic spine density that was accompanied with lower functional integration and cell survival. By taking advantage of the mosaic expression of transgenes in astrocytes, we found that spine density was reduced exclusively in segments intersecting blocked astrocytes, revealing an extrinsic, local control of spine formation. Defects in NMDA receptor (NMDAR)-mediated synaptic transmission and dendrite maturation were partially restored by exogenous D-serine, whose extracellular level was decreased in transgenic models. Together, these results reveal a critical role for adult astrocytes in local dendritic spine maturation, which is necessary for the NMDAR-dependent functional integration of newborn neurons

    Surgical resection is superior to TACE in the treatment of HCC in a well selected cohort of BCLC-B elderly patients—A retrospective observational study

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    Simple Summary Hepatocellular carcinoma (HCC) is the most common primary liver malignancy. Liver transplantation (LT) and surgical resection (SR) are currently the primary treatments with curative intent. Nevertheless, more than two-thirds of patients are elderly and, therefore, excluded from LT; while, according to the Barcelona Clinic Liver Cancer (BCLC) system, SR should only be offered to a small group of patients with early stage HCC. The identification in stage B of an intermediate subgroup of patients that fulfill the criteria for surgery may play an important role in the implementation of potentially curative treatments. Hepatocellular carcinoma (HCC) usually develops in cirrhotic liver, with high recurrence rates. However, considering its increasing detection in non-cirrhotic liver, the choice of treatment assumes particular relevance. This study aimed to investigate outcomes of patients among BCLC stages and enrolled for surgical resection (SR) according to a more complex evaluation, to establish its safety and efficacy. A total of 186 selected HCC patients (median age 73.2 yrs), submitted to SR between January 2005 and January 2021, were retrospectively analyzed. Of which, 166 were staged 0, A, B according to the BCLC system, while 20 with a single large tumor (&gt;5 cm) were classified as stage AB. No perioperative mortality was recorded; complications occurred in 48 (25.80%) patients, and all but two were Clavien-Dindo grade I-II. Median follow-up was 9.2 years. Subsequently, 162 recurrent patients (87,1%) were selected for new treatments. Comparable overall survival rates (OS) were observed at 1, 3, 5, and 10 years in 0, A, B and AB stages (p = 0.2). Eventually, the BCLC-B group was matched to 40 BCLC-B patients treated (2015-2021) with TACE. Significant differences in baseline characteristics (p &lt;0.0001) and in OS were observed at 1 and 3 years (p &lt;0.0001); a significant difference was also observed in oncological outcomes, in terms of the absence, residual, or relapse of disease (p &lt;0.05). Surgery might be a valid treatment in HCC for patients affected by chronic liver disease in a condition of compensation, up to BCLC-B stage. Surgical indication for liver resection in case of HCC should be extensively revised
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