129 research outputs found

    Classical and quantum harmonic mean-field models coupled intensively and extensively with external baths

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    We study the nonequilibrium steady-state of a fully-coupled network of N quantum harmonic oscillators, interacting with two thermal reservoirs. Given the long-range nature of the couplings, we consider two setups: one in which the number of particles coupled to the baths is fixed (intensive coupling) and one in which it is proportional to the size N (extensive coupling). In both cases, we compute analytically the heat fluxes and the kinetic temperature distributions using the nonequilibrium Green's function approach, both in the classical and quantum regimes. In the large N limit, we derive the asymptotic expressions of both quantities as a function of N and the temperature difference between the baths. We discuss a peculiar feature of the model, namely that the bulk temperature vanishes in the thermodynamic limit, due to a decoupling of the dynamics of the inner part of the system from the baths. At variance with the usual case, this implies that the steady-state depends on the initial state of the bulk particles. We also show that quantum effects are relevant only below a characteristic temperature that vanishes as 1/N. In the quantum low-temperature regime the energy flux is proportional to the universal quantum of thermal conductance

    Non-equilibrium steady states of long-range coupled harmonic chains

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    We perform a numerical study of transport properties of a one-dimensional chain with couplings decaying as an inverse power r−(1+σ)r^{-(1+\sigma)} of the intersite distance rr and open boundary conditions, interacting with two heat reservoirs. Despite its simplicity, the model displays highly nontrivial features in the strong long-range regime, −1<σ<0-1<\sigma<0. At weak coupling with the reservoirs, the energy flux departs from the predictions of perturbative theory and displays anomalous superdiffusive scaling of the heat current with the chain size. We trace back this behavior to the transmission spectrum of the chain, which displays a self-similar structure with a characteristic sigma-dependent fractal dimension.Comment: 9 pages, 8 figure

    De Episcopis Cardinalibus Suburbicariis quaestiones selectae : propositae ad usum Congregationis Casuum ...

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    Sign.: a4-b4, A4-M4.Grab. xil. en port

    Removal of micro-pollutants from urban wastewater by constructed wetlands with Phragmites australis and Salix matsudana

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    This study assessed the ability to remove micro-pollutants from wastewater using herbaceous species (Phragmites australis L.) and trees (Salix matsudana Koidz.) in constructed wetland (CW) systems. The targets of the study were as follows: (i) pharmaceuticals like diclofenac, ketoprofen, and atenolol; (ii) 4-n-NP (4-n-nonylphenol) and the ethoxylated derivatives monoethoxylated nonylphenol (NP1EO) and diethoxylated nonylphenol (NP2EO); (iii) triclosan, a bactericide used in personal care products. The 12 CW systems, filled with clay and gravel, were irrigated with wastewater from municipal area of Pagnana (Tuscany, Italy) and influent and effluent water samples analyzed periodically by gas chromatography-mass spectrometry (GC-MS/MS). The removal efficiency of CWs planted with willow and common red ranged from 8.4 up to 100%, with the higher removal efficiency for triclosan. On the contrary, the removal efficiency of NPs and NPEOs appears lower than pharmaceuticals. Data demonstrated that P. australis efficiently removed NP, diclofenac, and atenolol, while S. matsudana preferentially removed NP1EO, NP2EO, ketoprofene, and triclosan. A specific selection of plants used in CWs could be exploited for the removal of specific xenobiotics from wastewater

    Aluminum effects on embryo suspensor polytene chromosomes of Phaseolus coccineus L

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    Aluminum (Al) represents a widespread environmental pollutant, with severe toxic impacts on plants. In this study, we documented for the first time the structural and functional responses induced by two concentrations of AlCl3 (10−2 M and 10−1 M) in the polytene chromosomes that characterize the chromatin organization in the embryo suspensor cells of Phaseolus coccineus. Polytene chromosomes showed signs of dose-dependent genotoxicity following AlCl3 treatments with a significant increase in both chromatin stickiness and chromatin fragmentation. Polytene chromosomes specifically reacted to AlCl3 also in terms of DNA and RNA puffing activity: with respect to the control, the treatments promoted ex-novo and/or inhibited puff formation along chromosome arms, suggesting a fine modulation of the differential genome activity in response to the treatments. The nuclei of suspensors from control and treated seeds showed nucleoli mainly arranged by more than one NOR-bearing chromosome. In addition, AlCl3 treatments affected the frequency of nucleoli organized by singular organizer chromosomes, with an increase in the frequencies of nucleoli organized by chromosome II and a reduction in the frequencies of those organized by chromosomes I or V. These results confirm that, also in our system, nucleolus may react as stress response organelle. Introductio

    AQUA1 is a mercury sensitive poplar aquaporin regulated at transcriptional and post-translational levels by Zn stress

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    Aquaporins are water channel proteins that regulate plant development, growth, and response to environmental stresses. Populus trichocarpa is one of the plants with the highest number of aquaporins in its genome, but only few of them have been characterized at the whole plant functional level. Here we analyzed a putative aquaporin gene, aqua1, a gene that encodes for a protein of 257 amino acid with the typical NPA (Asp-Pro-Ala) signature motif of the aquaporin gene family. aqua1 was down-regulated of ∼10 fold under excess Zn in both leaves and roots, and conferred Zn tolerance when expressed in yeast Zn hypersensitive strain. In vivo localization of AQUA1-GFP in Arabidopsis protoplast showed a heterogeneous distribution of this protein on different membranes destined to form aggregates related to autophagic multivesicular bodies. Zn-dependent AQUA1-GFP re-localization was perturbed by phosphatases' and kinases' inhibitors that could affect both intracellular trafficking and aquaporins' activity. Exposed to high concentration of Zn, AQUA1 also co-localized with AtTIP1;1, a well-known Arabidopsis vacuolar marker, probably in pro-vacuolar multivesicular bodies. These findings suggest that high concentration of Zn down-regulates aqua1 and causes its re-localization in new forming pro-vacuoles. This Zn-dependent re-localization appears to be mediated by mechanisms regulating intracellular trafficking and aquaporins' post-translational modifications. This functional characterization of a poplar aquaporin in response to excess Zn will be a useful reference for understanding aquaporins' roles and regulation in response to high concentration of Zn in poplar

    A adequação dos meios de solução de conflitos na perspectiva dos direitos fundamentais: um ensaio pela cultura mediação e da paz

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    Notória a insatisfação para com o modelo tradicional de solução de conflitos, que consagra técnicas individualistas e procedimentos jurisdicionais estatais extremamente formais, que emperram a máquina judiciária estatal. Nessa perspectiva, surge a necessidade de revisitação e atualização do conceito de acesso à Justiça, tendo em vista a construção de um sistema multiportas, por meio do qual seja possível gerenciar os conflitos e solucioná-los pelos mecanismos de resolução mais aderentes e adequados à crise de direito material subjacente. Nesse contexto se destaca a mediação, meio consensual de solução de conflitos que, por meio do restabelecimento da comunicação entre os indivíduos em conflito, possibilita a construção da solução pelos próprios envolvidos no litígio, de sorte a estimular o exercício da cidadania e propiciar o desenvolvimento de uma cultura de pacificação

    Caratterizzazione fisiografica, geomorfologica e bionomica della <i>Rias</i> di Santa Teresa di Gallura: Sardegna nord-orientale = Physiographic, geomorphological and bionomic characterization of the Santa Teresa di Gallura <i>Rias</i> (N.E. Sardinia)

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    An underwater survey in the Rias of S. Teresa di Gallura was made to characterize the benthic environment by integrating three methods: Side Scan Sonar, ROV, SCUBA diving. The main bionomic features at different depths were described and mapped. The presence of Savalia savaglia, a rare Mediterranean species contributed to enhance the environmental value of the study area

    Emergency Resection for Colonic Cancer Has an Independent and Unfavorable Effect on Long-Term Oncologic Outcome

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    Background Long-term outcomes in patients undergoing emergency versus elective resection for colorectal cancer (CRC) remain controversial. This study aims to assess short- and long-term outcomes of emergency versus elective CRC surgery. Methods In this single-center retrospective cohort study, patients undergoing emergency or elective colonic resections for CRC from January 2013 to December 2017 were included. Primary outcome was long-term survival. As secondary outcomes, we sought to analyze potential differences on postoperative morbidity and concerning the oncological standard of surgical resection. The Kaplan-Meier curves and Cox proportional hazard model were used to compare survival between the groups. Results Overall, 225 CRC patients were included. Of these 192 (85.3%) had an elective and 33 (14.7%) an emergency operation. Emergency indications were due to obstruction, perforation, or bleeding. Patients in the emergency group had higher ASA score (p = 0.023), higher Charlsson comorbidity index (CCI, p = 0.012), and were older than those in the elective group, with median age 70 (IQR 63-79) years and 78 (IQR 68-83) years, for elective and emergency, respectively (p = 0.020). No other preoperative differences were observed. Patients in the emergency group experienced significantly more major complications (12.1% vs. 3.6%, p = 0.037), more anastomotic leakage (12.1% vs. 1.6%, p = 0.001), need for reoperation (12.1% vs. 3.1%, p = 0.021), and postoperative mortality (2 patients vs. 0, p &lt; 0.001). No differences in terms of final pathological stage, nor in accuracy of lymphadenectomy were observed. Overall survival was significantly worse in case of emergency operation, with estimated median 41 months vs. not reached in elective cases (p &lt; 0.001). At the multivariate analysis, emergency operation was confirmed as independent unfavorable determinant of survival (with hazard rate HR = 1.97, p = 0.028), together with age (HR = 1.05, p &lt; 0.001), postoperative major morbidity (HR = 3.18, p = 0.012), advanced stage (HR = 5.85, p &lt; 0.001), and need for transfusion (HR = 2.10, p = 0.049). Conclusion Postoperative morbidity and mortality were increased in emergency versus elective CRC resections. Despite no significant differences in terms of accuracy of resection and pathological stages, overall survival was significantly worse in patients who underwent emergency procedure, and independent of other determinants of survival
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