Variations on S-fold CFTs

A local SL(2,Z) transformation on the Type IIB brane configuration gives rise to an interesting class of superconformal field theories, known as the S-fold CFTs. Previously it has been proposed that the corresponding quiver theory has a link involving the T(U(N)) theory. In this paper, we generalise the preceding result by studying quivers that contain a T(G) link, where G is self-dual under S-duality. In particular, the cases of G = SO(2N), USp'(2N) and G_2 are examined in detail. We propose the theories that arise from an appropriate insertion of an S-fold into a brane system, in the presence of an orientifold threeplane or an orientifold fiveplane. By analysing the moduli spaces, we test such a proposal against its S-dual configuration using mirror symmetry. The case of G_2 corresponds to a novel class of quivers, whose brane construction is not available. We present several mirror pairs, containing G_2 gauge groups, that have not been discussed before in the literature.Comment: v2: minor corrections and references adde

Entropy function from toric geometry

It has recently been claimed that a Cardy-like limit of the superconformal index of 4d $\mathcal{N}=4$ SYM accounts for the entropy function, whose Legendre transform corresponds to the entropy of the holographic dual AdS$_5$ rotating black hole. Here we study this Cardy-like limit for $\mathcal{N}=1$ toric quiver gauge theories, observing that the corresponding entropy function can be interpreted in terms of the toric data. Furthermore, for some families of models, we compute the Legendre transform of the entropy function, comparing with similar results recently discussed in the literature.Comment: 34 pages, typos corrected in section 2, a reference adde

identificazione di geni differenzialmente espressi nel cervello di ratto dopo trattamento con acetil-L-carnitina

L’ Acetil-L-Carnitina ( ALC ) è una biomolecola ubiquitariamente distribuita nell’organismo e in particolare nel Sistema Nervoso Centrale, dove rappresenta l’estere di carnitina più abbondante. Diversi studi hanno dimostrato la validità delle applicazioni cliniche dell’ALC nel trattamento di pazienti affetti dal morbo di Alzheimer, nella sindrome cronica di affaticamento, nell’ ischemia, nell’ invecchiamento. L’ALC inoltre influenza positivamente la capacità di apprendimento, attenzione e memoria nei ratti vecchi trattati con tale sostanza. Studi comportamentali eseguiti sull’invertebrato Hirudo medicinalis hanno evidenziato che l’ALC è in grado di influenzare processi di apprendimento di tipo non associativo, in particolare, di bloccare la sensitizzazione e di ridurre la disabitudine nell’induzione al nuoto e che tali effetti permangono nel tempo. Il prolungarsi di cambiamenti comportamentali nel tempo ha suggerito che potesse in qualche modo essere modulata l’espressione genica . Lo scopo del nostro studio è stato quello di identificare geni che sono differenzialmente espressi nel cervello di giovani ratti sani dopo 21 giorni di trattamento con iniezioni intraperitoneali di ALC ( 100 mg/Kg ; gruppo sperimentale ) o soluzione salina ( gruppo di controllo ) . Le variazioni nel pattern di espressione genica, indotte dal trattamento, sono state analizzate utilizzando la tecnica dell’ibridazione sottrattiva soppressiva, SSH ( suppression subtractive hybridisation ).Questa tecnica permette di individuare geni la cui espressione può essere indotta, inibita o modulata da particolari stati fisiologici tramite la costruzione di librerie sottrattive di cDNA. In particolare, questa tecnica risulta efficiente nell’isolamento di trascritti rari non evidenziabili con altre tecniche che analizzano pattern di espressione genica. Precedentemente nei nostri laboratori l’utilizzo di questa tecnica ha permesso la costruzione di due librerie sottrattive di cDNA, forward e reverse, costituite rispettivamente dai trascritti dei geni la cui espressione è modulata positivamente o negativamente dal trattamento con ALC. I cDNA delle due librerie sono stati clonati e sottoposti a screening.I cloni ottenuti da ciascuna libreria sono stati circa 750, in questo studio sono stati riportati i dati relativi allo screening di circa 600 cloni. Lo screening primario ha permesso di selezionare i cloni differenzialmente espressi, eliminando i falsi positivi. Le sequenze dei cloni differenziali ,ottenute con sequenziatore automatico, sono state analizzate mediante comparazione con le sequenze depositate nella banca dati GenBank , EMBL , utilizzando programmi come FASTA , BLASTX e BLASTN. L’analisi dei più interessanti cDNA differenzialmente espressi ha mostrato omologia con sequenze codificanti proteine note, quali: ferritina, subunità H; pompa H+- ATPasica;; canale anionico voltaggio dipendente,VDCA1, citocromo b ossidasi, complesso bc1 . Al fine di confermare questi risultati sono in corso esperimenti di Northern blot e RT-PCR relativa

Sistemi informativi 3D per i BB.CC. e l'archeologia: il Castello di Maredolce a Palermo

Il mondo della ricerca nel campo dei BB.CC. sta guardando con sempre maggior interesse all’uso di tecnologie informatiche integrate, che consentano di fornire e condividere in rete dati quantitativi e qualitativi, geometrici, posizionali, alfanumerici, relativi ai BB.CC., sfruttando l’interazione tra banche dati e modelli 3D. Tali modelli, dunque, oltre a fornire una ricostruzione virtuale del monumento con la possibilità di navigare ed analizzare l’oggetto in dettaglio, costituiscono lo strumento per accedere ad informazioni eterogenee (testi, immagini, sequenze video, ecc.) sui manufatti, raccolte ed organizzate in database relazionali interrogabili, al fine di una piena comprensione e contestualizzazione degli stessi. In tale prospettiva, negli ultimi dieci anni, nell’ambito dei sistemi informativi territoriali sono stati fatti diversi passi avanti verso il GIS (Geographic Information System) 3D, in particolare nell’ambito della visualizzazione di oggetti tridimensionali all’interno di un sistema informativo geografico. I prototipi di sistemi GIS realmente 3D, tuttavia, sono ancora pochi e per la maggior parte dedicati alla descrizione di ambiti urbani. In tale contesto, la sperimentazione qui illustrata, realizzata all’interno del GISLab (CNR/UNIPA) di Palermo, è stata orientata verso l’implementazione di un sistema informativo 3D per la descrizione di beni archeologici e monumentali: in tale sistema l’informazione grafica di un modello tridimensionale, incorporato all’interno di un PDF 3D (formato di Acrobat Reader per lo scambio di documenti contenenti oggetti tridimensionali), è associata all’informazione semantica, allocata in un RDBMS (Relational DataBase Management System). Tale sperimentazione è stata applicata a scala territoriale al caso studio dei sollazzi arabo-normanni di Palermo e a scala architettonica e di dettaglio ad uno di essi: il Castello di Maredolce.Researchers in the field of Cultural Heritage are watching with increasing interest in the use of integrated computer technology: it allows to provide and share on the Internet both quantitative and qualitative data (geometric, positional, alphanumeric, etc.) related to Cultural Heritage, using the interaction between databases and 3D models. Such models, therefore, not only provide a virtual reconstruction of monuments as well as the browsing and the analysis of the subject in detail, but they also enable users to access to heterogeneous information (texts, images, video clips, etc.) on artifacts. Data are collected and organised in relational databases that are queriable, in order to a full understanding and contextualization of the cultural objects. In this perspective, in the last decade, we have been making several steps towards the 3D GIS (Geographic Information System), particularly in displaying three-dimensional objects within a geographic information system. The prototypes of effective 3D GIS systems, however, are still few and for the most part devoted to the description of urban areas. In this context, this research work, made within the GISLab (CNR / UNIPA) of Palermo, was aimed at implementing an information system for the description of 3D archaeological and monumental heritage: within this system the graphic information of a three-dimensional model, embedded within a 3D PDF (the Acrobat Reader format for exchanging documents, containing three-dimensional objects), is associated with semantic information, allocated in a RDBMS (Relational DataBase Management System). Such experimentation has been applied on a regional scale to the case study of the Arab-Norman "sollazzi" in Palermo and on an architectural and detailed scales to one of them: the Castle of Maredolce

Supersymmetric Indices of 3d S-fold SCFTs

Enhancement of global symmetry and supersymmetry in the infrared is one of the most intriguing phenomena in quantum field theory. We investigate such phenomena in a large class of three dimensional superconformal field theories, known as the S-fold SCFTs. Supersymmetric indices are computed for a number of theories containing small rank gauge groups. It is found that indices of several models exhibit enhancement of supersymmetry at the superconformal fixed point in the infrared. Dualities between S-fold theories that have different quiver descriptions are also analysed. We explore a new class of theories with a discrete global symmetry, whose gauge symmetry in the quiver has a different global structure from those that have been studied earlier.Comment: 32 pages and several figures. Version 2: minor corrections and references adde

Optimizar y facilitar el trabajo docente con herramientas digitales

Este trabajo se propone describir el modo en el que la Coordinación de los Cursos Especiales del Area de Inglés de la Escuela de Lenguas de la Universidad Nacional de La Plata hace uso de diversas herramientas digitales, tanto para el trabajo administrativo como para la enseñanza en los distintos cursos que la componen. En todos los casos, se expondrán los motivos pedagógicos que guiaron la selección de estos recursos y los fines para los que son empleados. Se hará referencia a las razones por las cuales la incorporación de estas herramientas permite simplificar el trabajo del personal de esta sección y, también, a las iniciativas relacionadas con su empleo en la enseñanza que ya se han puesto en práctica en los cursos de exámenes internacionales y en los Talleres de inglés para adultos mayores. Por último, se analizarán los resultados obtenidos en cada caso, pasando revista a las ventajas y los inconvenientes encontrados durante su implementaciónFil: Enríquez, Silvia Cecilia. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina

A non-contact optical technique for vehicle tracking along bounded trajectories

This paper presents a method for measuring the non-controlled trajectory of a cart along a bounded rectilinear path. The method uses non-contact measurement devices to identify the position of a movable laser scanner working in helical mode in order to reconstruct the 3D model of bridges. The main idea of the proposed method is to use vision systems in order to identify the coordinates of the laser scanner placed on the cart with respect to the global reference system. A fit-to-purpose vision system has been implemented: the system uses three CCD's cameras mounted on the cart to identify the relative rotations with respect to the environment. Two lasers pointers and a laser distance meter are fixed at the starting point of the trajectory and pointing in the direction of motion of the cart, creating three dots on a plane placed on the cart. One of the camera detects the cart displacements and rotations in the plane using a blob analysis procedure. The method described in this paper has a constant uncertainty and the measurement range only depends on the lasers power. The theoretical accuracy of the measurement system is close to 1 mm for the translation along the motion direction and around 0.5 mm along the other two directions. Orientations measurement have a theoretical accuracy of less than 0.1 °. The solution has been implemented for the 3D reconstruction of concrete bridge; preliminary experimental results are presented and discussed

The effects of methanol on the trapping of volatile ice components

The evaporation of icy mantles, which have been formed on the surface of dust grains, is acknowledged to give rise to the rich chemistry that has been observed in the vicinity of hot cores and corinos. It has long been established that water ice is the dominant species within many astrophysical ices. However, other molecules found within astrophysical ices, particularly methanol, can influence the desorption of volatile species from the ice. Here we present a detailed investigation of the adsorption and desorption of methanol-containing ices, showing the effect that methanol has on the trapping and release of volatiles from model interstellar ices. OCS and CO2 have been used as probe molecules since they have been suggested to reside in water-rich and methanol-rich environments. Experiments show that methanol fundamentally changes the desorption characteristics of both OCS and CO2, leading to the observation of mainly codesorption of both species with bulk water ice for the tertiary ices and causing a lowering of the temperature of the volcano component of the desorption. In contrast, binary ices are dominated by standard volcano desorption. This observation clearly shows that codepositing astrophysically relevant impurities with water ice, such as methanol, can alter the desorption dynamics of volatiles that become trapped in the pores of the amorphous water ice during the sublimation process. Incorporating experimental data into a simple model to simulate these processes on astrophysical timescales shows that the additional methanol component releases larger amounts of OCS from the ice mantle at lower temperatures and earlier times. These results are of interest to astronomers as they can be used to model the star formation process, hence giving information about the evolution of our Universe

A study of methyl formate in astrochemical environments

Several complex organic molecules are routinely detected in high abundances towards hot cores and hot corinos. For many of them, their paths of formation in space are uncertain, as gas phase reactions alone seem to be insufficient. In this paper, we investigate a possible solid-phase route of formation for methyl formate (HCOOCH3). We use a chemical model updated with recent results from an experiment where simulated grain surfaces were irradiated with 200 keV protons at 16 K, to simulate the effects of cosmic ray irradiation on grain surfaces. We find that this model may be sufficient to reproduce the observed methyl formate in dark clouds, but not that found in hot cores and corinos.Comment: 6 pages, 2 figures, 2 tables Accepted by MNRA