2,644 research outputs found
A topological approach to neural complexity
Considerable efforts in modern statistical physics is devoted to the study of
networked systems. One of the most important example of them is the brain,
which creates and continuously develops complex networks of correlated
dynamics. An important quantity which captures fundamental aspects of brain
network organization is the neural complexity C(X)introduced by Tononi et al.
This work addresses the dependence of this measure on the topological features
of a network in the case of gaussian stationary process. Both anlytical and
numerical results show that the degree of complexity has a clear and simple
meaning from a topological point of view. Moreover the analytical result offers
a straightforward algorithm to compute the complexity than the standard one.Comment: 6 pages, 4 figure
Comparison of the VIMOS-VLT Deep Survey with the Munich semi-analytical model. II. The colour-density relation up to z=1.5
[Abridged] We perform on galaxy mock catalogues the same colour-density
analysis made by Cucciati et al. (2006) on a 5 Mpc/h scale using the VVDS-Deep
survey, and compare the results from mocks with observed data. We use mocks
with the same flux limits (I=24) as the VVDS (CMOCKS), built using the semi-
analytic model by De Lucia & Blaizot (2007) applied to the Millennium
Simulation. From CMOCKS, we extracted samples of galaxies mimicking the VVDS
observational strategy (OMOCKS). We computed the B-band Luminosity Function LF
and the colour-density relation (CDR) in the mocks. We find that the LF in
mocks roughly agrees with the observed LF, but at z<0.8 the faint-end slope of
the model LF is steeper than the VVDS one. Computing the LF for early and late
type galaxies, we show that mocks have an excess of faint early-type and of
bright late-type galaxies with respect to data. We find that the CDR in OMOCKS
is in excellent agreement with the one in CMOCKS. At z~0.7, the CDR in mocks
agrees with the VVDS one (red galaxies reside mainly in high densities). Yet,
the strength of the CDR in mocks does not vary within 0.2<z<1.5, while the
observed relation flattens with increasing z and possibly inverts at z=1.3. We
argue that the lack of evolution in the CDR in mocks is not due only to
inaccurate prescriptions for satellite galaxies, but that also the treatment of
central galaxies has to be revised. The reversal of the CDR can be explained by
wet mergers between young galaxies, producing a starburst event. This should be
seen on group scales. A residual of this is found in observations at z=1.5 on
larger scales, but not in the mocks, suggesting that the treatment of physical
processes affecting satellites and central galaxies in models should be
revised.Comment: 15 pages, 12 figures, accepted for publication in A&
Neural detection of complex sound sequences in the absence of consciousness
Neural responses to violations of global regularities are thought to require consciousness. However, Tzovara et al. show that some comatose patients can also detect deviations in sequences composed of repeated groups of sounds, suggesting that the unconscious brain has a greater capacity to track sensory inputs than previously believe
The VIMOS-VLT Deep Survey: Dependence of galaxy clustering on stellar mass
We have investigated the dependence of galaxy clustering on their stellar
mass at z~1, using the data from the VIMOS-VLT Deep Survey (VVDS). We have
measured the projected two-point correlation function of galaxies, wp(rp) for a
set of stellar mass selected samples at an effective redshift =0.85. We have
control and quantify all effects on galaxy clustering due to the incompleteness
of our low mass samples. We find that more massive galaxies are more clustered.
When compared to similar results at z~0.1 in the SDSS, we observed no evolution
of the projected correlation function for massive galaxies. These objects
present a stronger linear bias at z~1 with respect to low mass galaxies. As
expected, massive objects at high redshift are found in the highest pics of the
dark matter density field.Comment: 4 pages, 2 figures, 43rd Rencontres de Moriond - March 15-22, 2008 -
La Thuile (Val d'Aosta, Italy
Reply: Neural detection of complex sound sequences or of statistical regularities in the absence of consciousness?
IL MUSEO DELL’OSSERVATORIO VESUVIANO E IL SUO PUBBLICO. ANNI 2005 - 2009
The Vesuvius Observatory, first volcanological observatory in the world, was built in 1841 by King Ferdinand II of Bourbon. It is now the Naples section of the National Institute of Geophysics and Volcanology (INGV). Since its foundation it has been not only a reference point for national and international scientific community, but also a place of information and dissemination for the population in the field of research and monitoring of volcanic phenomena. Always museum activities, guided tours through the collections of scientific instruments, rocks and minerals have been carried out in it.
Since 2000 scientific and historical collections located into the old building of Vesuvius Observatory have been organized in the exhibition "Vesuvius: 2000 years of observations", which describes the eruptive
history of Somma-Vesuvius, with the aim of providing updated information about monitoring of active volcanoes, on eruptive phenomena and related hazards, educating the population of areas exposed to volcanic hazards.
The museum path is targeted to public of any geographical origin and cultural background and could be considered a journey through the history of volcanology from the beginning until the present day.
In the exhibition, Vesuvius is the backdrop to an exhibition in which purely scientific elements coexist with historical, archaeological, literary, artistic aspects, thanks to the support of images, documents such as the geological map of Henry James Johnston-Lavis and the book "Campi Flegrei" by William Hamilton, specimens of rocks and minerals and old scientific instruments, used in the past for monitoring volcanic activity, including the first electromagnetic seismograph made by Luigi Palmieri.
The first part of this work is focussed on the description of the existing exhibition.
Since 2000 the statistical survey of the public of the museum has been carried out through an evaluation procedure form. The findings relate to the monthly and annual attendance, geographical origin and kind of visitors. In the second part of this work results for the five years from 2005 to 2009 are described.
The characterization of different audiences in the museum means that, from time to time, the path of the visit could be arranged according to the expectations and needs of visitors; in this context, the museum
educator plays the delicate role of mediator, with accurate language, between the contents of the museum and those who interact with it
COVID-19 infection and rheumatoid arthritis: Faraway, so close!
The outbreak of the new coronavirus infections COVID-19 in December 2019 in China has quickly become a global health emergency. Given the lack of specific anti-viral therapies, the current management of severe acute respiratory syndrome coronaviruses (SARS-CoV-2) is mainly supportive, even though several compounds are now under investigation for the treatment of this life-threatening disease. COVID-19 pandemic is certainly conditioning the treatment strategy of a complex disorder as rheumatoid arthritis (RA), whose infectious risk is increased compared to the general population because of an overall impairment of immune system typical of autoimmune diseases combined with the iatrogenic effect generated by corticosteroids and immunosuppressive drugs. However, the increasing knowledge about the pathophysiology of SARS-CoV-2 infection is leading to consider some anti-rheumatic drugs as potential treatment options for the management of COVID-19. In this review we will critically analyse the evidences on either positive or negative effect of drugs commonly used to treat RA in this particular scenario, in order to optimize the current approach to RA patients
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