Search

The astrophysical journal / Supplement series 266(2), 37 (2023). doi:10.3847/1538-4365/acc181, We study the broadband emission of Mrk 501 using multiwavelength observations from 2017 to 2020 performed with a multitude of instruments, involving, among others, MAGIC, Fermi's Large Area Telescope (LAT), NuSTAR, Swift, GASP-WEBT, and the Owens Valley Radio Observatory. Mrk 501 showed an extremely low broadband activity, which may help to unravel its baseline emission. Nonetheless, significant flux variations are detected at all wave bands, with the highest occurring at X-rays and very-high-energy (VHE) $γ$-rays. A significant correlation (>3σ) between X-rays and VHE $γ$-rays is measured, supporting leptonic scenarios to explain the variable parts of the emission, also during low activity. This is further supported when we extend our data from 2008 to 2020, and identify, for the first time, significant correlations between the Swift X-Ray Telescope and Fermi-LAT. We additionally find correlations between high-energy γ-rays and radio, with the radio lagging by more than 100 days, placing the γ-ray emission zone upstream of the radio-bright regions in the jet. Furthermore, Mrk 501 showed a historically low activity in X-rays and VHE $γ$-rays from mid-2017 to mid-2019 with a stable VHE flux (>0.2 TeV) of 5% the emission of the Crab Nebula. The broadband spectral energy distribution (SED) of this 2 $γ$r long low state, the potential baseline emission of Mrk 501, can be characterized with one-zone leptonic models, and with (lepto)-hadronic models fulfilling neutrino flux constraints from IceCube. We explore the time evolution of the SED toward the low state, revealing that the stable baseline emission may be ascribed to a standing shock, and the variable emission to an additional expanding or traveling shock., Published by Institute of Physics Publ., London

Large-size Resistive Micromegas have been chosen for the upgrade of the forward muon spectrometer of the ATLAS experiment, the New Small Wheel project. These chambers, together with small-strip Thin Gap Chambers (sTGC), allow reconstruction of high-momentum muon tracks in a high-radiation environment and provide a robust low-threshold single-muon trigger. A collaboration of seven INFN units built 32 SM1 type chambers, corresponding to one fourth of the total number needed for this upgrade. Each SM1 chamber has a surface of approximately 2 m2 and four sensitive layers. The production was shared among five INFN construction sites and it was completed in fall 2020. The construction methods, as well as the results of the quality tests done on components of the detector and on the assembled chambers, are reported in the present paper.

El objetivo de este trabajo es celebrar más de tres décadas de la integración de los análisis de isótopos estables en investigaciones arqueológicas en nuestro país. Se presenta una síntesis sobre los conceptos,fundamentos teóricos y metodológicos y las aplicaciones, principalmente en tres grandes temas: paleodieta, paleomovilidad y paleoambiente. A su vez, brindamos ejemplos de abordajes isotópicos sobre problemáticas de paleodietas en sociedades cazadoras recolectoras y agricultoras; movilidad de grupos humanos; estrategias de pastoreo; preparación y cocción de alimentos; estudios paleoambientales y paleoclimáticos. Este compendio puede resultar una referencia útil para estudiantes e investigadores que decidan adentrarse en este campo de investigación. Los casos mencionados no agotan el estado de la cuestión, ni abarcan todas las regiones donde fueron desarrollados estos estudios, sino que el propósito es mostrar la diversidad temática y el modo en que los isótopos estables permiten ampliar el conocimiento sobre las sociedades en el pasado. The main goal of this work is to celebrate more than three decades of the application of stable isotope analyses in Argentinian archaeology. We present a synthesis of the concepts, theoretical and methodological aspects and applications covering three main topics: paleodiet, paleomobility and paleoenvironment. At the same time, we provide examples of isotopic approaches to study problems such as paleodiets in hunter-gatherer and agricultural societies, human mobility, herding strategies, food preparation and cooking, and paleoenvironmental and paleoclimatic studies. This compendium will be a useful reference for students and researchers inclined to enter this field of research. However, the cases mentioned here do not represent the state of art nor do they cover all the Argentinian regions where these studies were carried out, but rather show the thematic diversity and the way in which stable isotope analyses allow to broaden our knowledge about societies in the past. Introducción - Conceptos básicos, fundamentación y notación de los análisis de isótopos estables - Espectrometría de masas - Relaciones isotópicas mayormente utilizadas en arqueología -- Isótopos estables del carbono -- Isótopos estables del nitrógeno -- Isótopos estables del oxígeno e hidrógeno -- Otras relaciones isotópicas de interés: azufre y estroncio - Tejidos y materiales -- Tejidos biológicos -- Residuos orgánicos -- Carbonatos biogénicos -- Sedimentos - Conservación, contaminación y diagénesis -- Fracción orgánica o colágeno -- Fracción Mineral o Bioapatita - Discriminación y fraccionamiento isotópico - Interpretación paleodietaria y ecología isotópica - Abordajes isotópicos de problemáticas en arqueología argentina - Consideraciones finales y perspectivas futuras

The exhibition design has always been – among other design disciplines – one of the most innovative field of experimentation both for languages and projects improvement. The paper aims at studying the potential of art of being a metaphorical “tool” for the interior design approach both in terms of cultural exhibitions and installations. For this reason we present two groups of cases: cultural exhibitions designed by artists and artistic installations created by designers and architects. The relationship between the design approach and artistic installations can be seen in three dimensions of the design process: in exploring the theoretical meaning of the space (the art as a media to know novel vocations of spaces during the concept generation process); in experimenting the physical impact of the artifact in the space (the art as a matter of innovation during the verification of the project); in expressing innovative spatial concepts (the art as a “language” to communicate novel provocative and disruptive visions during the communication of the idea). In conclusion: we embrace the idea that art can be considered as a paradigmatic incubator in the process of “living” the Interiors. Starting from that, we are going to underline some methodological attitudes within the design culture in relation to the artistic research and to interpret new aesthetics.

Made available in DSpace on 2016-08-29T11:04:06Z (GMT). No. of bitstreams: 1 tese_8717_As interações da cultura midiática na escola - texto completo.pdf: 11467368 bytes, checksum: c0b63bdfb50734fafaf88ddf2b83b90e (MD5) Previous issue date: 2015-03-31 Pesquisa as interações da cultura midiática na escola. Problematiza o alto índice de consumo de mídia na atualidade e justifica a necessidade de pesquisas que deem conta de entender os sentidos dessa teia de interações, em especial a construção de sentido, em ato, entre crianças, adolescentes e cultura midiática. Adota como referencial teórico-metodológico a sociossemiótica baseando-se em Algirdas Julien Greimas, Eric Landowski, Ana Cláudia Oliveira e outros. Escolhe uma escola municipal, situada em Jardim Camburi, Vitória/Espírito Santo, como locus e sujeitos de estudo. Propõe como procedimentos metodológicos a pesquisa exploratória, descritiva e sociossemiótica, com tratamento de dados de forma qualitativa, com os métodos da observação participante, conversação, entrevista em profundidade e da pesquisa semiótica. Usa na coleta de dados as anotações em diário de bordo e fotografias. Contribui para o entendimento da construção de sentido que se estabelece, em ato, entre crianças, adolescentes e cultura midiática, e apresenta sugestões de diálogo construtivo a ser promovido pela escola.

Le antenne integrate attive (AIA), rappresentano la nuova frontiera nella progettazione dei moderni sistemi a radiofrequenza e ad onde millimetriche, sia per applicazioni militari che per applicazioni commerciali. Negli ultimi anni, la progettazione dell’antenna, oltre al raggiungimento dei requisiti sul diagramma di irradiazione, sul guadagno e sull’adattamento di impedenza, richiede una forte integrazione dell’elemento radiante nel sistema. Infatti, nei sistemi di trasmissione, ed in special modo in quelli mobili, è di fondamentale importanza ridurre al minimo la dissipazione di potenza in continua, per aumentare la durata delle batterie e per ridurre il peso e l’ingombro dell’intera unità, riducendo sia le dimensioni dei sistemi di alimentazione che dei sistemi di raffreddamento. Fattori cruciali nelle scelte progettuali saranno quindi l’efficienza, le dimensioni e la larghezza di banda, oltre al controllo delle interferenze elettromagnetiche tra i vari sottosistemi. Allo scopo di investigare questi nuovi concetti e sviluppare strutture innovative, è stato proposto e finanziato il progetto PRIN’05 dal titolo “Antenne Integrate Attive per Terminali Mobili ad Alta Efficienza”. Il progetto di ricerca si pone come obiettivo lo sviluppo di un’antenna integrata attiva per terminali mobili ad alta efficienza per applicazioni in banda Ku. Gli aspetti innovativi proposti riguardano la possibilità di integrazione dell’elettronica di front-end con l’elemento radiante, al fine di migliorare le prestazioni dell’intero trasmettitore. Le problematiche di rilievo sono l’integrazione dello stadio di potenza con il singolo elemento radiante, lo sviluppo di oscillatori VCO basati su1 concetto di injection locking per l’implementazione di array fasati e lo studio delle problematiche di sviluppo di array ad alta efficienza. Per quanto riguarda lo stadio di potenza integrato con l’elemento radiante, l’idea è stata quella di usare quest’ultimo anche come carico armonico per l’ottimizzazione delle prestazioni dello stadio di potenza.

A novel predistortion approach well suited for MMIC design is discussed. The theoretical analysis shows third-order intermodulation product (IMP3) cancellation independent of the specific technology exploited for implementation and of the detailed behaviour of the power stage nonlinearity; further improvements can be obtained through optimization. The active stages of the predistorter are modeled through a nonlinear describing function, which can be experimentally characterized through standard LS S-parameters measurements. The predistortion scheme has been implemented within the Agilent ADS environment and applied to the linearity optimization of a power amplifier stage. In accordance with theoretical results, significant improvement in the linearity of the Pin-Pout is demonstrated together with IMP3 reduction. A sensitivity analysis on the optimization parameters is also presented, showing that this approach is robust and well suited for circuit design.

This paper presents a new RF dynamic behavioral model based on a neural network (NN) approach suitable for FET devices in a wide range of working classes, and capable to identify the device response, through the training procedure, for a wide range of input power levels. The presented model has been effectively applied to GaN-based devices at 1 GHz, working in class A and B.

An extensive power characterization of devices fabricated on GaN grown on SiC and sapphire substrates has been carried out, including powers weep and load-pull measurements in different bias conditions from class A to class B. An active load-pull bench optimized for high voltage and high power measurements allows to extend the load-pull characterization to the whole Smith chart, and to localize the optimum load conditions even for devices with almost reactive optimum terminations. The characterization procedure allows to verify scaling rules and the effects of defects and thermal degradation on the device power performances. The results of the SiC and sapphire-based devices show that, on one side, SiC-based devices exibit state-of-the-art performances in Class A, and, on the other side, low-cost sapphire-based devices, when biased in high efficiency classes, can be viable candidates for medium power applications, despite the higher thermal resistivity of sapphire compared with the one of SiC.

The paper presents a measurement-based largesignal distributed model for high-speed electroabsorption modulators, integrated within an RF circuit CAD environment. The model is implemented through a cascaded-cell approach; the identification of the nonlinear lumped equivalent circuit parameters of each cell through measurements is discussed and an example is provided of circuit extraction. An example of integrated driver-EAM simulation is finally discussed.