988 resultados para Ribé, Maria Carme
Resumo:
Aquest treball presenta una anàlisi textual de l'obra de Maria Aurèlia Capmany 'Feliçment, jo sóc una dona'. D'una banda, a través d'una breu presentació de l'autora fins al moment de la publicació de l'obra i, d'una altra, d'una síntesi del feminisme a Catalunya, l'autora del treball ens apropa a les teories feministes que Capmany aboca en la seva novel·la, fet que representa un punt d'inflació en la seva trajectòria novel·lística. L'anàlisi textual ens permet apropar-nos al concepte d'identitat femenina i a la seva construcció, així com relacionar-lo amb les teories feministes més recents.
Resumo:
MGRO J2019+37 is an unidentified extended source of very high energy gamma-rays originally reported by the Milagro Collaboration as the brightest TeV source in the Cygnus region. Its extended emission could be powered by either a single or several sources. The GeV pulsar AGL J2020.5+3653 , discovered by AGILE and associated with PSR J2021+3651 , could contribute to the emission from MGRO J2019+37 . Aims. Our aim is to identify radio and near-infrared sources in the field of the extended TeV source MGRO J2019+37 , and study potential counterparts to explain its emission. Methods. We surveyed a region of about 6 square degrees with the Giant Metrewave Radio Telescope (GMRT) at the frequency 610 MHz. We also observed the central square degree of this survey in the near-infrared -band using the 3.5 m telescope in Calar Alto. Archival X-ray observations of some specific fields are included. VLBI observations of an interesting radio source were performed. We explored possible scenarios to produce the multi-TeV emission from MGRO J2019+37 and studied which of the sources could be the main particle accelerator. Results. We present a catalogue of 362 radio sources detected with the GMRT in the field of MGRO J2019+37 , and the results of a cross-correlation of this catalog with one obtained at near-infrared wavelengths, which contains ~3105 sources, as well as with available X-ray observations of the region. Some peculiar sources inside the ~1° uncertainty region of the TeV emission from MGRO J2019+37 are discussed in detail, including the pulsar PSR J2021+3651 and its pulsar wind nebula PWN G75.2+0.1 , two new radio-jet sources, the H II region Sh 2-104 containing two star clusters, and the radio source NVSS J202032+363158 . We also find that the hadronic scenario is the most likely in case of a single accelerator, and discuss the possible contribution from the sources mentioned above. Conclusions. Although the radio and GeV pulsar PSR J2021+3651 / AGL J2020.5+3653 and its associated pulsar wind nebula PWN G75.2+0.1 can contribute to the emission from MGRO J2019+37 , extrapolation of the GeV spectrum does not explain the detected multi-TeV flux. Other sources discussed here could contribute to the emission of the Milagro source.
Resumo:
One fundamental question about pulsars concerns the mechanism of their pulsed electromagnetic emission. Measuring the high-end region of a pulsar's spectrum would shed light on this question. By developing a new electronic trigger, we lowered the threshold of the Major Atmospheric γ-ray Imaging Cherenkov (MAGIC) telescope to 25 giga-electron volts. In this configuration, we detected pulsed γ-rays from the Crab pulsar that were greater than 25 giga-electron volts, revealing a relatively high cutoff energy in the phase-averaged spectrum. This indicates that the emission occurs far out in the magnetosphere, hence excluding the polar-cap scenario as a possible explanation of our measurement. The high cutoff energy also challenges the slot-gap scenario.
Resumo:
The Cherenkov light flashes produced by Extensive Air Showers are very short in time. A high bandwidth and fast digitizing readout, therefore, can minimize the influence of the background from the light of the night sky, and improve the performance in Cherenkov telescopes. The time structure of the Cherenkov image can further be used in single-dish Cherenkov telescopes as an additional parameter to reduce the background from unwanted hadronic showers. A description of an analysis method which makes use of the time information and the subsequent improvement on the performance of the MAGIC telescope (especially after the upgrade with an ultra fast 2 GSamples/s digitization system in February 2007) will be presented. The use of timing information in the analysis of the new MAGIC data reduces the background by a factor two, which in turn results in an enhancement of about a factor 1.4 of the flux sensitivity to point-like sources, as tested on observations of the Crab Nebula.
Resumo:
We present the results of stereoscopic observations of the satellite galaxy Segue 1 with the MAGIC Telescopes, carried out between 2011 and 2013. With almost 160 hours of good-quality data, this is the deepest observational campaign on any dwarf galaxy performed so far in the very high energy range of the electromagnetic spectrum. We search this large data sample for signals of dark matter particles in the mass range between 100 GeV and 20 TeV. For this we use the full likelihood analysis method, which provides optimal sensitivity to characteristic gamma-ray spectral features, like those expected from dark matter annihilation or decay. In particular, we focus our search on gamma-rays produced from different final state Standard Model particles, annihilation with internal bremsstrahlung, monochromatic lines and box-shaped signals. Our results represent the most stringent constraints to the annihilation cross-section or decay lifetime obtained from observations of satellite galaxies, for masses above few hundred GeV. In particular, our strongest limit (95% confidence level) corresponds to a ~ 500 GeV dark matter particle annihilating into τ+τ−, and is of order langleσannvrangle simeq 1.2 × 10−24 cm3 s−1 a factor ~ 40 above the langleσannvrangle simeq thermal value.
Resumo:
Maria Teresa Codina i Mir és una mestra i pedagoga que ha tingut especial rellevància en la pedagogia del segle XX a Catalunya. Durant la seva trajectòria personal i professional ha estat compromesa en l’educació dels sectors socials més desfavorits i en la renovació pedagògica de Catalunya. Aquesta tasca tan important que ha dut a terme de manera silenciosa, no pot ser ignorada. Amb aquest treball pretenem analitzar-la i donar-la a conèixer. És per aquest motiu que hem fet una aproximació biogràfica de la vida i idees pedagògiques de Maria Teresa Codina a partir de la veu de persones que l’han coneguda i que han estat significatives en la seva vida. A través de successives entrevistes i l’anàlisi de documents personals i inèdits de Codina, volem aprofundir en la seva trajectòria personal i professional i conèixer les seves idees educatives des d’una visió més propera, viva i humana.
Resumo:
Maria Àngels Anglada tenia una clara consciència del lloc, que va deixar una empremta profunda en la seva obra literària. L’article analitza les visions que l’autora dóna de Vic, la ciutat natal, a través de la poesia, la narrativa i la prosa assagística. En particular, l’anàlisi se centra en el relat de fons autobiogràfic No em dic Laura. Aquest text vehicula una dura crítica política, social i moral del Vic sotmès a la dictadura franquista. I, alhora, constitueix la millor mostra del vigatanisme crític que caracteritza l’autora.
Resumo:
En els anys vuitanta i noranta, Maria Àngels Anglada s’endinsà en l’art de la traducció i traslladà alguns títols, majoritàriament clàssics, amb l’objectiu de recuperar noms poc atesos pels discursos literaris del nostre país. Se centrà en quatre textos: Les germanes de Safo (1983), Epigrames (1993), L’esplanada (1987), i, amb Maria Ohannesian, Terra porpra i altres poemes. Anglada també va fer feina de torsimany en els seus tres llibres de viatges Paisatge amb poetes (1988), Paradís amb poetes (1993) i Retalls de la vida a Grècia i Roma (1997).
Resumo:
Tutkielmassa analysoidaan Maria Jotunin Miehen kylkiluu -näytelmän interrogatiivi- ja direktiivimuotoisia ilmauksia. Lisäksi tarkastellaan kysymisen ja käskemisen funktiossa käytettyjä kieliopillisten rakenteiden toissijaisia käyttöjä. Aineistoa tutkitaan kahdesta näkökulmasta: yhtäältä ilmausten pintamuotojen yhteyttä niiden puhefunktioihin ja toisaalta ilmausten puhefunktioiden ja illokuutioiden vaikutuksia puhetilanteissa. Pragmaattisen näkökulman myötä tarkastelussa otetaan huomioon myös tutkittavien ilmausten aiheuttamat reaktiot ja vastaukset. Tutkielmassa käytetty interrogatiivi- ja direktiivirakenteiden muodollinen jaottelu pohjautuu pääosin Isoon suomen kielioppiin. Pragmaattisen tarkastelun taustana on J. L. Austinin ja J. Searlen ajatusten pohjalta syntynyt puheaktiteoria ja puheaktien illokuutioiden luokittelu. Puheaktiteoreettista ajattelua soveltaen tutkielmassa selvitetään aineiston yksittäisten ilmausten vaikutuksia puhetilanteissa ja analysoidaan niiden illokutiivisia sävyjä. Lausumien puhefunktioiden ja niiden vaikutusten tulkinta edellyttää usein laajankin kontekstin huomioimista. Analyysissä havainnoidaan myös jonkin verran kohteliaisuuden ja erilaisten sosiolingvististen seikkojen yhteyttä niin kielellisiin rakenteisiin kuin pragmaattiseen kontekstiin. Ilmausten pintamuotojen suhteesta niiden puhefunktioihin voi tutkielman aineiston perusteella todeta analyysin vahvistaneen teorialuvuissa esitettyä kielioppeihin perustuvaa suomen kielen kysymys- ja käskyrakenteiden muodollista ja funktionaalista jaottelua. Määrällisestä suppeudestaan huolimatta tutkielman aineisto on monipuolinen. Miehen kylkiluu -näytelmä sisältää laajan läpileikkauksen tutkimusaiheen kannalta oleellisista suomen kielen rakenteista ja niiden käytöistä. Tutkielman pragmaattisesta näkökulmasta voi aineiston perusteella yleisenä huomiona esittää puhujien illokuutioiden yleensä toteutuvan. Tämä lienee seurausta keskustelun yleisien yhteistyön periaatteiden noudattamisesta. Lisäksi esimerkiksi suorat imperatiivimuotoiset käskyt tietyissä vuorovaikutuskonteksteissa esitettyinä eivät jätä puhuteltavalle mahdollisuuksia kieltäytymiseen.
Resumo:
Here we discuss two consecutive MERLIN observations of the X-ray binary LS I +61° 303 . The first observation shows a double-sided jet extending up to about 200 AU on both sides of a central source. The jet shows a bent S-shaped structure similar to the one displayed by the well-known precessing jet of SS 433 . The precession suggested in the first MERLIN image becomes evident in the second one, showing a one-sided bent jet significantly rotated with respect to the jet of the day before. We conclude that the derived precession of the relativistic (beta=0.6) jet explains puzzling previous VLBI results. Moreover, the fact that the precession is fast could be the explanation of the never understood short term (days) variability of the associated gamma-ray source 2CG 135+01 / 3EG J0241+6103
Resumo:
We present Very Long Baseline Interferometry (VLBI) observations of the high mass X-ray binary LS I +61˚303, carried out with the European VLBI Network (EVN). Over the 11 hour observing run, performed ~10 days after a radio outburst, the radio source showed a constant flux density, which allowed sensitive imaging of the emission distribution. The structure in the map shows a clear extension to the southeast. Comparing our data with previous VLBI observations we interpret the extension as a collimated radio jet as found in several other X-ray binaries. Assuming that the structure is the result of an expansion that started at the onset of the outburst, we derive an apparent expansion velocity of 0:003 c, which, in the context of Doppler boosting, corresponds to an intrinsic velocity of at least 0:4 c for an ejection close to the line of sight. From the apparent velocity in all available epochs we are able to establish variations in the ejection angle which imply a precessing accretion disk. Finally we point out that LS I +61˚303, like SS 433 and Cygnus X-1, shows evidence for an emission region almostorthogonal to the relativistic jet
Resumo:
Context. MGRO J2019+37 is an unidentified extended source of very high energy gamma-rays originally reported by the Milagro Collaboration as the brightest TeV source in the Cygnus region. Its extended emission could be powered by either a single or several sources. The GeV pulsar AGL J2020.5+3653, discovered by AGILE and associated with PSR J2021+3651, could contribute to the emission from MGRO J2019+37. Our aim is to identify radio and near-infrared sources in the field of the extended TeV source MGRO J2019+37, and study potential counterparts to explain its emission. Methods: We surveyed a region of about 6 square degrees with the Giant Metrewave Radio Telescope (GMRT) at the frequency 610 MHz. We also observed the central square degree of this survey in the near-infrared Ks-band using the 3.5 m telescope in Calar Alto. Archival X-ray observations of some specific fields are included. VLBI observations of an interesting radio source were performed. We explored possible scenarios to produce the multi-TeV emission from MGRO J2019+37 and studied which of the sources could be the main particle accelerator. Results: We present a catalogue of 362 radio sources detected with the GMRT in the field of MGRO J2019+37, and the results of a cross-correlation of this catalog with one obtained at near-infrared wavelengths, which contains ∼3 × 105 sources, as well as with available X-ray observations of the region. Some peculiar sources inside the ∼1◦ uncertainty region of the TeV emission from MGRO J2019+37 are discussed in detail, including the pulsar PSR J2021+3651 and its pulsar wind nebula PWN G75.2+0.1, two new radio-jet sources, the Hii region Sh 2-104 containing two star clusters, and the radio source NVSS J202032+363158. We also find that the hadronic scenario is the most likely in case of a single accelerator, and discuss the possible contribution from the sources mentioned above. Conclusions: Although the radio and GeV pulsar PSR J2021+3651 / AGL J2020.5+3653 and its associated pulsar wind nebula PWN G75.2+0.1 can contribute to the emission from MGRO J2019+37, extrapolation of the GeV spectrum does not explain the detected multi-TeV flux. Other sources discussed here could contribute to the emission of the Milagro source
Resumo:
The autophagic process is a lysosomal degradation pathway, which is activated during stress conditions, such as starvation or exercise. Regular exercise has beneficial effects on human health, including neuroprotection. However, the cellular mechanisms underlying these effects are incompletely understood. Endurance and a single bout of exercise induce autophagy not only in brain but also in peripheral tissues. However, little is known whether autophagy could be modulated in brain and peripheral tissues by long-term moderate exercise. Here, we examined the effects on macroautophagy process of long-term moderate treadmill training (36 weeks) in adult rats both in brain (hippocampus and cerebral cortex) and peripheral tissues (skeletal muscle, liver and heart). We assessed mTOR activation and the autophagic proteins Beclin 1, p62, LC3B (LC3B-II/LC3B-I ratio) and the lysosomal protein LAMP1, as well as the ubiquitinated proteins. Our results showed in the cortex of exercised rats an inactivation of mTOR, greater autophagy flux (increased LC3-II/LC3-I ratio and reduced p62) besides increased LAMP1. Related with these effects a reduction in the ubiquitinated proteins was observed. No significant changes in the autophagic pathway were found either in hippocampus or in skeletal and cardiac muscle by exercise. Only in the liver of exercised rats mTOR phosphorylation and p62 levels increased, which could be related with beneficial metabolic effects in this organ induced by exercise. Thus, our findings suggest that long-term moderate exercise induces autophagy specifically in the cortex