62 research outputs found
The non-linear q-voter model
We introduce a non-linear variant of the voter model, the q-voter model, in
which q neighbors (with possible repetition) are consulted for a voter to
change opinion. If the q neighbors agree, the voter takes their opinion; if
they do not have an unanimous opinion, still a voter can flip its state with
probability . We solve the model on a fully connected network (i.e.
in mean-field) and compute the exit probability as well as the average time to
reach consensus. We analyze the results in the perspective of a recently
proposed Langevin equation aimed at describing generic phase transitions in
systems with two ( symmetric) absorbing states. We find that in mean-field
the q-voter model exhibits a disordered phase for high and an
ordered one for low with three possible ways to go from one to the
other: (i) a unique (generalized voter-like) transition, (ii) a series of two
consecutive Ising-like and directed percolation transition, and (iii) a series
of two transitions, including an intermediate regime in which the final state
depends on initial conditions. This third (so far unexplored) scenario, in
which a new type of ordering dynamics emerges, is rationalized and found to be
specific of mean-field, i.e. fluctuations are explicitly shown to wash it out
in spatially extended systems.Comment: 9 pages, 7 figure
The synaptic vesicle protein CSP alpha prevents presynaptic degeneration
Cysteine string protein α (CSPα)âan abundant synaptic vesicle protein that contains a DNA-J domain characteristic of Hsp40 chaperonesâis thought to regulate Ca2+ channels and/or synaptic vesicle exocytosis. We now show that, in young mice, deletion of CSPα does not impair survival and causes no significant changes in presynaptic Ca2+ currents or synaptic vesicle exocytosis as measured in the Calyx of Held synapse. At 2â4 weeks of age, however, CSPα-deficient mice develop a progressive, fatal sensorimotor disorder. The neuromuscular junctions and Calyx synapses of CSPα-deficient mice exhibit increasing neurodegenerative changes, synaptic transmission becomes severely impaired, and the mutant mice die at âŒ2 months of age. Our data suggest that CSPα is not essential for the normal operation of Ca2+ channels or exocytosis but acts as a presynaptic chaperone that maintains continued synaptic function, raising the possibility that enhanced CSPα function could attenuate neurodegenerative diseases
The CANDELS/SHARDS multiwavelength catalog in GOODS-N : photometry, photometric redshifts, stellar masses, emission-line fluxes, and star formation rates
We present a WFC3 F160W (H-band) selected catalog in the CANDELS/GOODS-N field containing photometry from the ultraviolet (UV) to the far-infrared (IR), photometric redshifts, and stellar parameters derived from the analysis of the multiwavelength data. The catalog contains 35,445 sources over the 171 arcmin(2) of the CANDELS F160W mosaic. The 5 sigma detection limits (within an aperture of radius 0 ''.17) of the mosaic range between H = 27.8, 28.2, and 28.7 in the wide, intermediate, and deep regions, which span approximately 50%, 15%, and 35% of the total area. The multiwavelength photometry includes broadband data from the UV (U band from KPNO and LBC), optical (HST/ACS F435W, F606W, F775W, F814W, and F850LP), near-to-mid IR (HST/WFC3 F105W, F125W, F140W, and F160W; Subaru/MOIRCS Ks; CFHT/Megacam K; and Spitzer/IRAC 3.6, 4.5, 5.8, and 8.0 mu m), and far-IR (Spitzer/MIPS 24 mu m, HERSCHEL/PACS 100 and 160 mu m, SPIRE 250, 350 and 500 mu m) observations. In addition, the catalog also includes optical medium-band data (R similar to 50) in 25 consecutive bands, lambda = 500-950 nm, from the SHARDS survey and WFC3 IR spectroscopic observations with the G102 and G141 grisms (R similar to 210 and 130). The use of higher spectral resolution data to estimate photometric redshifts provides very high, and nearly uniform, precision from z = 0-2.5. The comparison to 1485 good-quality spectroscopic redshifts up to z similar to 3 yields Delta z/(1 + z(spec)) = 0.0032 and an outlier fraction of eta = 4.3%. In addition to the multiband photometry, we release value-added catalogs with emission-line fluxes, stellar masses, dust attenuations, UV- and IR-based star formation rates, and rest-frame colors
Euclid preparation. XXXI. Performance assessment of the NISP Red-Grism through spectroscopic simulations for the Wide and Deep surveys
This work focuses on the pilot run of a simulation campaign aimed at
investigating the spectroscopic capabilities of the Euclid Near-Infrared
Spectrometer and Photometer (NISP), in terms of continuum and emission line
detection in the context of galaxy evolutionary studies. To this purpose we
constructed, emulated, and analysed the spectra of 4992 star-forming galaxies
at using the NISP pixel-level simulator. We built the
spectral library starting from public multi-wavelength galaxy catalogues, with
value-added information on spectral energy distribution (SED) fitting results,
and from Bruzual and Charlot (2003) stellar population templates. Rest-frame
optical and near-IR nebular emission lines were included using empirical and
theoretical relations. We inferred the 3.5 NISP red grism spectroscopic
detection limit of the continuum measured in the band for star-forming
galaxies with a median disk half-light radius of \ang{;;0.4} at magnitude ABmag for the Euclid Wide Survey and at ABmag for the Euclid Deep Survey. We found a very good
agreement with the red grism emission line detection limit requirement for the
Wide and Deep surveys. We characterised the effect of the galaxy shape on the
detection capability of the red grism and highlighted the degradation of the
quality of the extracted spectra as the disk size increases. In particular, we
found that the extracted emission line signal to noise ratio (SNR) drops by
45 when the disk size ranges from \ang{;;0.25} to \ang{;;1}. These
trends lead to a correlation between the emission line SNR and the stellar mass
of the galaxy and we demonstrate the effect in a stacking analysis unveiling
emission lines otherwise too faint to detect.Comment: 23 pages, 21 figure
Local disorder and structure relation induced by magnetic exchange interactions in A2(Mo1 12yMny)2O7 pyrochlores
We present an extended X-ray absorption fine structure study at the Mo K-edge of A2(Mo1 12yMny)2O7 (A = Gd, Ho; y = 0.05 and 0.10) pyrochlores, as a function of temperature and composition, coupled to diffractometric and magnetic characterizations. Extending the study reported in our previous paper on the pristine A2Mo2O7 compounds to these Mo/Mn partially substituted samples, where we hypothesize a competition between double-exchange and superexchange couplings, we aim to check which structure parameters are related to the nature of the nearest-neighbor magnetic interactions, looking for the presence and evolution of order and structure anomalies. Two Ho samples Ho2(Mo1 12yMny)2O7 (y = 0.05 and 0.10) keep the spin-glass nature of the parent compositions with a strong distortion of the MoO(1)6 octahedron and of the Mo\u2012Ho and Mo\u2012Mo second shell. On the other hand, two Gd2(Mo1 12yMny)2O7 samples, ferromagnetic at low temperature in the undoped case, show the appearance on a local scale of a spin-glass transition mirrored by a quite high structure disorder and by a distortion coherent with a lattice frustration after Mn-doping. Therefore, the Gd and Ho Mn-doped samples display a similar frustrated behavior, differently from the corresponding undoped ones
Clinical Guidelines: A Crossroad of Many Research Areas. Challenges and Opportunities in Process Mining for Healthcare
14siClinical Guidelines, medical protocols, and other healthcare indications, cover a significant slice of physicians daily routine, as they are used to support clinical choices also with relevant legal implications. On the one hand, informatics have proved to be a valuable mean for providing formalisms, methods, and approaches to extend clinical guidelines for better supporting the work performed in the healthcare domain. On the other hand, due to the different perspectives that can be considered for addressing similar problems, it lead to an undeniable fragmentation of the field. It may be argued that such fragmentation did not help to propose a practical, accepted, and extensively adopted solutions to assist physicians. As in Process Mining as a general field, Process Mining for Healthcare inherits the requirement of Conformance Checking. Conformance Checking aims to measure the adherence of a particular (discovered or known) process with a given set of data, or vice-versa. Due to the intuitive similarities in terms of challenges and problems to be faced between conformance checking and clinical guidelines, one may be tempted to expect that the fragmentation issue will naturally arise also in the conformance checking field. This position paper is a first step on the direction to embrace experience, lessons learnt, paradigms, and formalisms globally derived from the clinical guidelines challenge. We argue that such new focus, joint with the even growing notoriety and interest in PM4HC, might allow more physicians to make the big jump from user to protagonist becoming more motivated and proactive in building a strong multidisciplinary community.nonenoneGatta R.; Vallati M.; Fernandez-Llatas C.; Martinez-Millana A.; Orini S.; Sacchi L.; Lenkowicz J.; Marcos M.; Munoz-Gama J.; Cuendet M.; de Bari B.; Marco-Ruiz L.; Stefanini A.; Castellano M.Gatta, R.; Vallati, M.; Fernandez-Llatas, C.; Martinez-Millana, A.; Orini, S.; Sacchi, L.; Lenkowicz, J.; Marcos, M.; Munoz-Gama, J.; Cuendet, M.; de Bari, B.; Marco-Ruiz, L.; Stefanini, A.; Castellano, M
Origin of the magnetic transition at 100 K in ϵ-Fe2O3nanoparticles studied by x-ray absorption fine structure spectroscopy
The current study unveils the structural origin of the magnetic transition of the \ucf\ub5-Fe2O3polymorph from an incommensurate magnetic order to a collinear ferrimagnetic state at low temperature. The high crystallinity of the samples and the absence of other iron oxide polymorphs have allowed us to carry out temperature-dependent x-ray absorption fine structure spectroscopy experiments out. The deformation of the structure is followed by the Debye-Waller factor for each selected Fe-O and Fe-Fe sub-shell. For nanoparticle sizes between 7 and 15 nm, the structural distortions between the Feteand Fe-D1ocsites are localized in a temperature range before the magnetic transition starts. On the contrary, the inherent interaction between the other sub-shells (named Fe-O1,2 and Fe-Fe1) provokes cooperative magneto-structural changes in the same temperature range. This means that the Fetewith Fe-D1oc polyhedron interaction seems to be uncoupled with temperature dealing with these nanoparticle sizes wherein the structural distortions are likely moderate due to surface effects
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