1,355,478 research outputs found
Osservazioni su una metafora strutturale
No full textDies ist eine veröffentlichte Manuskriptfassung, welche veröffentlicht wurde in: Pirazzini, Daniela; Santulli, Francesca; Detti, Tommaso: "Übersetzen als Verhandlung", in der Buchreihe "Bonner Romanistische Arbeiten". © Peter Lang GmbH 2012. Alle Rechte vorbehaltenIn his book "Dire quasi la stessa cosa. Esperienze di traduzione" (2003) Eco conceptualizes translation as a negotiation process between conflicting parties. Having verified the existence of a metaphor which connects translation with negotiation, we pose the following question: If it is true that there are two different concepts of negotiation, is it also true that there are two different concepts of translation? In order to answer this question we contrast Eco's statements with those of Benjamin, analyzing both on the basis of the metaphor translation-negotiation.1. Introduzione
2. Primo modello concettuale Traduzione-Negoziazione
3. Negoziazione e perdita
4. Secondo modello concettuale Traduzione-Negoziazione
5. Negoziazione e guadagnoConvegno internazionale "Tradurre è –anche – scomettere. Oder die Übersetzung als 'negozianione'" (Bonn, 22-24 nomembre 2010)
Il cimitero ebraico di Lugo
No full textIl volume fornisce il testo ebraico annotato e una versione italiana degli epitaffi incisi sulle lapidi conservate nell'attuale cimitero ebraico di Lugo, in cui si trovano sia le stele ivi trasportate dal vecchio cimitero verso il 1877 sia quelle posate successivamente. Le ampie introduzioni sulla presenza ebraica a Lugo, sulla storia del suo cimitero, sull'epitaffio come genere letterario e fonte storica e sulle moltissime fonti prodotte dagli ebrei lughesi mostrano come nel Sei-Settecento Lugo fosse uno dei centri più fecondi e importanti della cultura ebraica in Italia. Situata nel Ducato di Ferrara, la cittadina divenne di grande importanza come centro ebraico dopo che nel 1639 papa Urbano VIII ordinò a tutti gli ebrei del ducato di concentrarsi nei ghetti di Ferrara, Lugo e Cento. Anche se vantava una presenza ebraica precedente, con questo decreto papale il centro romagnolo vide un aumento esponenziale della sua popolazione ebraica, che raggiunse oltre seicento persone, pari al dieci per cento di tutti gli abitanti. Già nel tardo Cinquecento, ma specialmente durante l'età barocca, gli epitaffi divennero vere e proprie poesie in rima e ritmo, che, arricchite da citazioni bibliche e rabbiniche, costituiscono sia pregievoli documenti letterari che interessanti fonti storiche: essi forniscono preziose informazioni su personaggi noti e meno noti e sulle loro reciproche relazioni parentali. Durante lo studio delle epigrafi è stato possibile identificare la lapide di Dawid Semu'el Del Vecchio, illustre rabbino lughese che nel 1807 partecipò al Grand Sanhedrin, convocato a Parigi da Napoelone, nonché quelle di suo suocero e di altre personalità. Di grandissimo interesse per completare la ricostruzione storica si è dimostrata l'integrazione dei dati contenuti negli epitaffi con quelli contenuti nel registro dei morti della comunità di Lugo, documento che copre un arco di quasi due secoli e che oggi è conservato a New York. Un sedicesimo di immagini a colori e un indice dei nomi in ebraico e in italiano arricchiscono e rendono agevole la consultazione del volume, che nelle appendici presenta anche due cippi funerari ebraici del Cinquecento conservati a Ravenna, uno scoperto nella vicina Bagnacavallo, e due note in memoria di alcuni membri delle famiglie ebraiche lughesi Sinigaglia e Marach. Grazie alla ricomposizione delle tessere di questo affascinante mosaico, si apre al lettore uno spettacolare squarcio sulla vita e la cultura di una comunità ebraica nell'Italia settentrionale dei secoli XVII-XIX
Construction of a Hierarchical Organization in Semantic Memory: A Model Based on Neural Masses and Gamma-Band Synchronization
No full textSemantic memory is characterized by a hierarchical organization of concepts based on shared properties. However, this aspect is insufficiently dealt with in recent neurocomputational models. Moreover, in many cognitive problems that exploit semantic memory, gamma-band synchronization can be relevant in favoring information processing and feature binding. In this work, we propose an attractor network model of semantic memory. Each computational unit, coding for a different feature, is described with a neural mass circuit oscillating in the gamma range. The model is trained with an original nonsymmetric Hebb rule based on a presynaptic gating mechanism. After training, the network creates a taxonomy of categories, distinguishes between subordinate and superordinate concepts, and discriminates between salient and marginal features. Examples are provided concerning a fourteen-animal taxonomy, including several subcategories. A sensitivity analysis reveals the robustness of the network but also points out conditions leading to confusion among categories, similar to the one observed in dreaming and some neurological disorders. Finally, the analysis emphasizes the role of fast GABAergic interneurons and inhibitory-excitatory balance to allow the correct synchronization of features. The model represents an original attempt to deal with a hierarchical organization of objects in semantic memory and correlated patterns, still exploiting gamma-band synchronization to favor neural processing. The same ideas, introduced in a more sophisticated multilayer network, can deepen our knowledge of semantic memory organization in the brain. Finally, they can open new perspectives in quantitatively analyzing neurological disorders connected with distorted semantics
Theta–gamma coupling as a ubiquitous brain mechanism: implications for memory, attention, dreaming, imagination, and consciousness
No full textBrain rhythms are known to play a relevant role in many cognitive functions. In particular, coupling between theta and gamma oscillations was first observed in the hippocampus, where it is assumed to implement a code for organizing multiple items in memory. More recent advances, however, demonstrate that this mechanism is ubiquitously present in the brain and plays a role not only in working memory but also in episodic and semantic memory, attention, emotion, dreaming, and imagination. Furthermore, altered mental states and neurological disorders show profound alterations in the theta–gamma code. In this review, which summarizes the most recent experimental and theoretical evidence, we suggest that the substantial capacity to integrate information characteristic of the theta–gamma entrainment is fundamental for implementing many conscious cognitive processes
Conflict or Dialogue? Legal Argumentation and the Search for Truth
No full textThe paper deals with the topic of legal argumentation with respect to evidentiary issues and the search of truth in a trial. It claims that adversary procedures are the best means for the discovery of truth, contrary to some recent criticism of them as being "fight" devices.
The volume collects several contributions, from scholars of different countries, on the subject of dialogue in argumentation, in a multidisciplinary perspective
Challenges in searching for therapeutics against Botulinum Neurotoxins
No full textBotulinum neurotoxins (BoNTs) are the most potent toxins known. BoNTs are responsible for botulism, a deadly neuroparalytic syndrome caused by the inactivation of neurotransmitter release at peripheral nerve terminals. Thanks to their specificity and potency, BoNTs are both considered potential bio-weapons and therapeutics of choice for a variety of medical syndromes. Several variants of BoNTs have been identified with individual biological properties and little antigenic relation. This expands greatly the potential of BoNTs as therapeutics but poses a major safety problem, increasing the need for finding appropriate antidotes. Areas covered: The authors describe the multi-step molecular mechanism through which BoNTs enter nerve terminals and discuss the many levels at which the toxins can be inhibited. They review the outcomes of the different strategies adopted to limit neurotoxicity and counter intoxication. Potential new targets arising from the last discoveries of the mechanism of action and the approaches to promote neuromuscular junction recovery are also discussed. Expert opinion: Current drug discovery efforts have mainly focused on BoNT type A and addressed primarily light chain proteolytic activity. Development of pan-BoNT inhibitors acting independently of BoNT immunological properties and targeting a common step of the intoxication process should be encouraged
Modeling the contribution of theta-gamma coupling to sequential memory, imagination, and dreaming
No full textGamma oscillations nested in a theta rhythm are observed in the hippocampus, where are assumed to play a role in sequential episodic memory, i.e., memorization and retrieval of events that unfold in time. In this work, we present an original neurocomputational model based on neural masses, which simulates the encoding of sequences of events in the hippocampus and subsequent retrieval by exploiting the theta-gamma code. The model is based on a three-layer structure in which individual Units oscillate with a gamma rhythm and code for individual features of an episode. The first layer (working memory in the prefrontal cortex) maintains a cue in memory until a new signal is presented. The second layer (CA3 cells) implements an auto-associative memory, exploiting excitatory and inhibitory plastic synapses to recover an entire episode from a single feature. Units in this layer are disinhibited by a theta rhythm from an external source (septum or Papez circuit). The third layer (CA1 cells) implements a hetero-associative net with the previous layer, able to recover a sequence of episodes from the first one. During an encoding phase, simulating high-acetylcholine levels, the network is trained with Hebbian (synchronizing) and anti-Hebbian (desynchronizing) rules. During retrieval (low-acetylcholine), the network can correctly recover sequences from an initial cue using gamma oscillations nested inside the theta rhythm. Moreover, in high noise, the network isolated from the environment simulates a mind-wandering condition, randomly replicating previous sequences. Interestingly, in a state simulating sleep, with increased noise and reduced synapses, the network can “dream” by creatively combining sequences, exploiting features shared by different episodes. Finally, an irrational behavior (erroneous superimposition of features in various episodes, like “delusion”) occurs after pathological-like reduction in fast inhibitory synapses. The model can represent a straightforward and innovative tool to help mechanistically understand the theta-gamma code in different mental states
The entry of tetanus and botulinum neurotoxins into neurons
No full textTetanus and botulinum neurotoxins cause neuroparalysis by inhibiting neuroexocytosis. They are composed by two main chains: the 100 kDa heavy chain (H) mediates the neurospecific binding to target cells and chaperons the entry of the 50 kDa light chain (L). After binding on the plasma membrane, these neurotoxins enter into nerve terminals via endocytosis inside synaptic vesicles, as shown here for the first time by immuno-electron microscopy. The lumenal acidic pH induces a structural change of the neurotoxin molecule that becomes capable of translocating its L chain into the cytosol, via a transmembrane protein-conducting channel made by the H chain. This is the least understood step of the intoxication process primarily because it takes place inside vesicles within the cytosol. In the present study, we describe how this passage can be made accessible to investigation by making it to occur at the plasma membrane of neurons. The neurotoxin, bound to the plasma membrane of cerebellar granular neurons in the cold, was exposed to a low pH extracellular medium and the entry of the L chain was monitored by measuring its specific metalloprotease activity with a ratiometric method. We found that the neurotoxin has to be bound to the membrane via at least two anchorage sites in order for a productive low-pH induced structural change to take place. In addition, this process can only occur if the single inter-chain disulfide bond is intact. The pH dependence of the conformational change of tetanus neurotoxin (TeNT) and botulinum neurotoxin (BoNT) /B, /C and /D is similar and takes place in the same slightly acidic range, which comprises that present inside synaptic vesicles. Thanks to this reliable method we have also studied the temperature dependence and the time course of TeNT, BoNT/C and BoNT/D L chain entry across the plasma membrane. The time course of translocation of the L chain varies for the three neurotoxins, but remains in the range of minutes at 37 °C, whilst it takes much longer at °20 C. BoNT/C does not enter neurons at 20 °C. Translocation also depends on the dimension of the pH gradient. These data are discussed with respect to the contribution of the membrane translocation step to the total time to paralysis and to the low toxicity of these neurotoxins in cold-blood vertebrates.
Another fundamental event along CNTs neuron intoxication process is the reduction of the interchain disulphide bond. This is a conditio sine qua non to free the catalytic part of the molecule in the cytosol of neurons. By using specific inhibitors of the various cytosolic protein disulfides reducing systems, we show here that the NADPH-Thioredoxin reductase-Thioredoxin redox system is the main responsible for this disulfide reduction. In addition, we indicate auranofin, as a possible basis for the design of novel inhibitors of these neurotoxins.
BoNT/A is the most frequent cause of human botulism and at the same time is largely used in human therapy. Some evidences indicate that it enters inside nerve terminals via endocytosis of synaptic vesicles, though this has not been formally proven. The metalloprotease L chain of the neurotoxin then reaches the cytosol in a process driven by low pH, but the acidic compartment wherefrom it translocates has not been identified. Using immunoelectron microscopy, we show that BoNT/A does indeed enter inside synaptic vesicles and that each vesicle contains either one or two toxin molecules. This finding indicates that it is the BoNT/A protein receptor SV2, and not its polysialoganglioside receptor that determines the number of toxin molecules taken up by a single vesicle. In addition, by rapid quenching the vesicle transmembrane pH gradient, we show that translocation of the neurotoxin into the cytosol is a fast process. Taken together, these results strongly indicate that translocation of BoNT/A takes place from synaptic vesicles, and not from endosomal compartments, and that the translocation machinery is operated by one or two neurotoxin molecules.
Another important aspect regarding CNTs research is their employment in human therapy. Accordingly, BoNT/A is almost invariably used in the treatment of many human diseases characterized by hyperactivity of peripheral cholinergic nerve terminals. Unfortunately, some patients are or become resistant to it. This drawback can be overcome by using other botulinum toxins, and pre-clinical studies have been performed with different toxin serotypes. Botulinum neurotoxin type D has never been tested in human muscles in vivo. Here we show that BoNT/D is very effective upon injection in mice, on the mouse hemidiaphragm preparation and on different rat primary neuronal cultures. From these experiments, doses to be injected in human volunteers were determined. The effect of the injection into the human Extensor Digitorum Brevis muscle was assayed by measuring the compound muscle action potential at different times after injection. Botulinum toxin type D was found to be very uneffective in inducing human skeletal muscle paralysis. These results are interpreted in terms of recent reports on neuronal surface receptors of this neurotoxin and of the established double receptor model of binding
Tetanus and tetanus neurotoxin: From peripheral uptake to central nervous tissue targets
No full textTetanus is a deadly but preventable disease caused by a protein neurotoxin produced by Clostridium tetani. Spores of C. tetani may contaminate a necrotic wound and germinate into a vegetative bacterium that releases a toxin, termed tetanus neurotoxin (TeNT). TeNT enters the general circulation, binds to peripheral motor neurons and sensory neurons, and is transported retroaxonally to the spinal cord. It then enters inhibitory interneurons and blocks the release of glycine or GABA causing a spastic paralysis. This review attempts to correlate the metalloprotease activity of TeNT and its trafficking and localization into the vertebrate body to the nature and sequence of appearance of the symptoms of tetanus. (Figure presented.)
Automated microwave device characterization set-up based on a technology-independent generalized Bias System
No full textIn this paper an automated laboratory set-up for the characterization of micro- and millimeter-wave electron devices under DC, small- and large-signal operation is described, which is based on a generalized, technology-independent bias system. The biasing parameters adopted, which are a linear combination between currents and voltages at the device ports, allow for a complete characterization of the desired empirical data (e.g. multi-frequency S-matrix) throughout all the regions in which the quiescent operation of the device can be conventionally divided, without any need for the switch between different biasing strategies. The look-up tables of experimental data obtained, which are carried out homogeneously with respect to the same couple of bias parameters, independently of the quiescent regions investigated, are particularly suitable for the characterization of empirical non-linear dynamic models for the electron device
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