1,869 research outputs found
Symmetries of L\'evy processes on compact quantum groups, their Markov semigroups and potential theory
Strongly continuous semigroups of unital completely positive maps (i.e.
quantum Markov semigroups or quantum dynamical semigroups) on compact quantum
groups are studied. We show that quantum Markov semigroups on the universal or
reduced C-algebra of a compact quantum group which are translation
invariant (w.r.t. to the coproduct) are in one-to-one correspondence with
L\'evy processes on its -Hopf algebra. We use the theory of L\'evy processes
on involutive bialgebras to characterize symmetry properties of the associated
quantum Markov semigroup. It turns out that the quantum Markov semigroup is
GNS-symmetric (resp. KMS-symmetric) if and only if the generating functional of
the L\'evy process is invariant under the antipode (resp. the unitary
antipode). Furthermore, we study L\'evy processes whose marginal states are
invariant under the adjoint action. In particular, we give a complete
description of generating functionals on the free orthogonal quantum group
that are invariant under the adjoint action. Finally, some aspects of
the potential theory are investigated. We describe how the Dirichlet form and a
derivation can be recovered from a quantum Markov semigroup and its L\'evy
process and we show how, under the assumption of GNS-symmetry and using the
associated Sch\"urmann triple, this gives rise to spectral triples. We discuss
in details how the above results apply to compact groups, group C-algebras
of countable discrete groups, free orthogonal quantum groups and the
twisted quantum group.Comment: 54 pages, thoroughly revised, to appear in the Journal of Functional
Analysi
Sinestesia in architettura. Parole e musica. Progetto architettonico e studio illuminotecnico e acustico di una biblioteca e auditorium a Pontassieve (Firenze)
La presente Tesi di Laurea ha come oggetto la progettazione architettonica, integrata da uno studio illuminotecnico e acustico, di una biblioteca di quartiere, con annesso auditorium, nel Comune di Pontassieve (Firenze).
Il tema scaturisce dalla proposta progettuale avanzata dal Comune per la sistemazione del Parco comunale adiacente a Piazza della LibertĂ , situato nel quartiere denominato âI Villiniâ, a sud â est di Pontassieve capoluogo.
Lo scopo essenziale della Tesi è quello di realizzare un progetto che assuma il ruolo di nuovo centro propulsore della vita culturale del quartiere e che sia dotato di una portata innovativa, pur nella continuitĂ e nel dialogo con le preesistenze e lâambiente circostante.
La multidisciplinaritĂ dellâintero iter progettuale, ovvero il continuo dialogo tra la materia compositivo-architettonica e quella illuminotecnico-acustica, si accorda coerentemente con lâispirazione alla base del progetto, derivata dalla figura retorica della sinestesia, un fenomeno percettivo che unisce diversi campi semantici e sensoriali
The Italian Retranslations of Virginia Woolf's To the Lighthouse: A Corpus-based Literary Analysis
The research goal is to clarify how and to what degree the modernist style and features of Virginia Woolfâs To the Lighthouse are rendered in the eleven retranslations into Italian of this novel and whether these can be characterised as modernist novels themselves. A suitable methodology has been developed, which is drawn on the existing corpus methods for descriptive translation studies. Empirical evidence of the differences between target texts have been found, which in many cases have been interpreted as due to the translatorsâ voice or thumb-prints. The present research uses a systematic literary comparison of the retranslations by adopting a mixed-method and bottom-up (inductive) approach by developing an empirical corpus approach. This corpus is specifically tailored to identify and study both linguistic and non-linguistic modernist features throughout the texts such as stream of consciousness-indirect interior monologue and free indirect speech. All occurrences will be analysed in this thesis in the computations of inferential and comparative statistics such as lexical variety and lexical frequency. The target texts were digitised, and the resulting text files were then analysed by using a bespoke, novel computer program, which is capable of the mentioned functions not provided by commercially available software such as WordSmith Tools and WMatrix. Not only did this methodology enable performing in-depth explorations of micro- and macro-textual features, but it also allowed a mixed-method approach combining close-reading qualitative analysis with systematic quantitative comparisons. The obtained empirical results identify a progressive source-text orientation of the retranslations of Woolfâs style in a few aspects of a few target texts. The translatorsâ presence affected all the eleven target texts in register and style under the influence of the Italian translation norms usually attributed to the translation of literary classics
Retranslating Virginia Woolf's To the Lighthouse in Modernist and Post-modernist Italy: A Corpus-based Study
A corpus-based analysis is employed to study the literary style's evolution in eleven Italian retranslations of Virginia Woolf's To the Lighthouse. The aim is to examine how and to what degree the literary movements have affected the target texts. During the twentieth century, increasing criticism, scepticism, and distance concerning the world's traditional vision and life were reflected in post-modernist literature, although in different ways across the European countries. New literary forms took place also in Italian literature. Woolf's novel's modernist features are a case in point to test Berman's Retranslation Hypothesis, which states that further retranslations tend to be text-source-oriented. This close-reading analysis partially confirms the proposed theory and indicates that the examined retranslations also remain relatively distant from the modernist and post-modernist experiments in Italy
Mantle-Crust Isotopic Relationships along Mid Ocean Ridges: Constraints from the Analysis of Time Series
Isotopic relationships between parent mantle and
daughter MORBs have been used to reveal the composite
nature of the source tracking the missing components in their
isotopic fingerprints. An opportunity to address this issue is
given by temporal sections of single ridge segments where
MORB and residual parent mantle peridotites can be assessed
together. The possibility has been offered by the flexured and
uplifted lithospheric slab that exposes, on the sea floor along
a seafloor spreading flow line, a zero to 26 Ma relatively
undisturbed lithospheric section (Vema Lithospheric Section
or VLS) generated at the 80 km long Mid Atlantic ridge
segment (EMAR) at 11°N.
Temporal variations of the Nd isotopic composition of
crustal basalts and parental mantle along the VLS reveal a
large dispersion of residual isotopic composition with respect
to the melt products. Equilibration with partially mixed melts
can account for the observed relationships in the mantle
rocks. The mean MORB isotopic composition and the
average composition of the residues do not match because of
the preferential extraction of the low-melting component. The
compositional difference in both isotopic and elemental
distribution is a function of the average degree of melting of
the mantle. This observation can only be justified by
progressive melting of composite lithologies where mantle
potential temperature and amount of dispersed low-melting
lithologies control the relative extent of melting of the mantle
host and that of the dispersed heterogeneities resulting in
differential fractions of mixed melts in the final products.
This observation is confirmed by global correlations in Nd
isotopes and chemical indicators of degree of melting from
other portions of the mid ocean ridge system
Pyroxenites sow discord between parent mantle and daughter MORB
Mantle rocks and MORBs sampled along the 26 Ma
record of the Vema Lithospheric Section or VLS (Mid
Atlantic 11\ub0N) reveal a profound divergence between parent
and daughter rocks in their compositional evolution. Finding
the cause of this discordance requires comparing the
evolution through time of the extent of melting with the
produced crustal thickness and changes in the chemistry and
isotopic composition of the sampled rocks. Mantle rocks
show a progressive increase of their degree of melting during
time, as if the potential temperature had increased in the last
26 Ma. However, plate kinematics reveal a significant
decrease of the spreading rate that should sensibly lower the
average degree of melting. MORB inferred degree of melting
decreases through time while their isotopic fingerprint
becomes more depleted. The observed variations can be
reconciled by considering that a variable amount of lowmelting
lithologies entered the melting region. The observed
decoupling of the degree of melting of mantle and MORB is
attributed to the effect of undercooling exerted by lowmelting
heterogeneities due to heat diffusion before the host
mantle starts melting itself. The observed temporal evolution
is matched by a decreasing amount of low-melting,
isotopically enriched, lithologies (pyroxenites) dispersed in a
DMM-type host mantle. Approaching the present day setting,
the amount of pyroxenites has become negligible restoring
harmony between parent mantle and MORB daughters in
terms of degree of melting and integrated melt production.
This observation can be extended to the entire MOR
system revealing the sensitivity of the spreading system to the
amount of low-melting lithologies dispersed in the depleted
mantle host. At limit conditions of the mantle potential
temperature, heat diffusion into the low-solidus melting
lithology prevents the host mantle from reaching its solidus
Nonchondritic 142Nd in suboceanic mantle peridotites
The discovery that several solid Earth reservoirs have a superchondritic 142Nd/144Nd ratio led to the hypothesis that either the bulk silicate Earth is not chondritic or that a subchondritic reservoir lies hidden somewhere within the Earth's interior. One important reservoir, i.e., mid-ocean ridge peridotites representing the main component of the upper oceanic mantle and the source of mid-ocean ridge basalt, has never been tested for 142Nd/144Nd. We determined the 142Nd/144Nd ratio in clinopyroxene separated from two peridotites and a pyroxenite from the SW Indian Ridge and one peridotite from the northern Mid-Atlantic Ridge. All samples analyzed have superchondritic 142Nd/144Nd ratios in line with mantle-derived material measured to date, except for some ancient cratonic rocks
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Water-rich basalts at mid-ocean-ridge cold spots
Although water is only present in trace amounts in the suboceanic upper mantle, it is thought to play a significant role in affecting mantle viscosity, melting and the generation of crust at mid-ocean ridges. The concentration of water in oceanic basalts has been observed to stay below 0.2wt%, except for water-rich basalts sampled near hotspots and generated by 'wet' mantle plumes. Here, however, we report unusually high water content in basaltic glasses from a cold region of the mid-ocean-ridge system in the equatorial Atlantic Ocean. These basalts are sodium-rich, having been generated by low degrees of melting of the mantle, and contain unusually high ratios of light versus heavy rare-earth elements, implying the presence of garnet in the melting region. We infer that water-rich basalts from such regions of thermal minima derive from low degrees of 'wet' melting greater than 60 km deep in the mantle, with minor dilution by melts produced by shallower 'dry' meltingâa view supported by numerical modelling. We therefore conclude that oceanic basalts are water-rich not only near hotspots, but also at 'cold spots'
Spatial ecology of moose in Sweden: Combined Sr-O-C isotope analyses of bone and antler
The study of spatial (paleo)ecology in mammals is critical to understand how animals adapt
to and exploit their environment. In this work we analysed the 87Sr/86Sr, δ18O and δ13C isotope
composition of 65 moose bone and antler samples from Sweden from wild-shot individuals
dated between 1800 and 1994 to study moose mobility and feeding behaviour for
(paleo)ecological applications. Sr data were compared with isoscapes of the Scandinavian
region, built ad-hoc during this study, to understand how moose utilise the landscape in
Northern Europe. The 87Sr/86Sr isoscape was developed using a machine-learning
approach with external geo-environmental predictors and literature data. Similarly, a δ18O
isoscape, obtained from average annual precipitation δ18O values, was employed to highlight
differences in the isotope composition of the local environment vs. bone/antler. Overall,
82% of the moose samples were compatible with the likely local isotope composition (n =
53), suggesting that they were shot not far from their year-round dwelling area. âLocalâ samples
were used to calibrate the two isoscapes, to improve the prediction of provenance for
the presumably ânon-localâ individuals. For the latter (n = 12, of which two are antlers and ten
are bones), the probability of geographic origin was estimated using a Bayesian approach
by combining the two isoscapes. Interestingly, two of these samples (one antler and one
bone) seem to come from areas more than 250 km away from the place where the animals
were hunted, indicating a possible remarkable intra-annual mobility. Finally, the δ13C data
were compared with the forest cover of Sweden and ultimately used to understand the dietary
preference of moose. We interpreted a difference in δ13C values of antlers (13Cenriched)
and bones (13C-depleted) as a joint effect of seasonal variations in moose diet
and, possibly, physiological stresses during winter-time, i.e., increased consumption of
endogenous 13C-depleted lipids
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