Time evolution of the extremely diluted Blume-Emery-Griffiths neural network

The time evolution of the extremely diluted Blume-Emery-Griffiths neural network model is studied, and a detailed equilibrium phase diagram is obtained exhibiting pattern retrieval, fluctuation retrieval and self-sustained activity phases. It is shown that saddle-point solutions associated with fluctuation overlaps slow down considerably the flow of the network states towards the retrieval fixed points. A comparison of the performance with other three-state networks is also presented.Comment: 8 pages, 5 figure

Correlation of internal representations in feed-forward neural networks

Feed-forward multilayer neural networks implementing random input-output mappings develop characteristic correlations between the activity of their hidden nodes which are important for the understanding of the storage and generalization performance of the network. It is shown how these correlations can be calculated from the joint probability distribution of the aligning fields at the hidden units for arbitrary decoder function between hidden layer and output. Explicit results are given for the parity-, and-, and committee-machines with arbitrary number of hidden nodes near saturation.Comment: 6 pages, latex, 1 figur

A canonical ensemble approach to graded-response perceptrons

Perceptrons with graded input-output relations and a limited output precision are studied within the Gardner-Derrida canonical ensemble approach. Soft non- negative error measures are introduced allowing for extended retrieval properties. In particular, the performance of these systems for a linear and quadratic error measure, corresponding to the perceptron respectively the adaline learning algorithm, is compared with the performance for a rigid error measure, simply counting the number of errors. Replica-symmetry-breaking effects are evaluated.Comment: 26 pages, 10 ps figure

Prilagodba usnih organa kod nekih podzemnih holevina (Cholevinae) (Coleoptera, Leiodidae)

Cholevinae are a group of beetles with many cave representatives that are mainly detritivorous or saprophagous. Some species show modifications of the mouthparts on account of their dietary niche, being adapted to a semi-aquatic way of life, or on account of the degree of adaptation to the life in caves. Differences are obvious also among the genera, and cave species that are at the same level of adaptation. The main modifications concern the shape and structure of the different parts, as well as their length and the disposal of hairs, bristles and setae. The adaptation to an aquatic dietary niche has modified the mandibles, which acquired a spoon-like form to bring water near the mouth, the lacinia taking on the role of stirring and the galea of filtering the organic particles with its fine and very dense hairs. The apparent uniformity of the subterranean environmental conditions and of the trophic resources, together with the scarcity of the latter, might mistakenly lead to the conclusion of a one-way evolution for the underground colonizers. The observed differences between the mouthparts of the studied species can be good material for taxonomists, who can include some of these features in their studies, often difficult due to the homogenous morphology of many inhabitants of the underground. As a contribution to the comparative study of the mouthparts at some representatives of cholevin beetles, we can also highlight the effect of adaptation to cave life on the mouthparts and the evidence of a divergent evolution in a relatively constant environment in terms of climate and food input.Holevine su skupina kornjaša s mnogo podzemnih predstavnika koji su pretežno detritivorni ili saprofagni. Neke vrste pokazuju modifikacije usnih organa zbog svoje prehrambene niše, prilagođavajući se poluakvatičkom načinu života, ili zbog stupnja adaptacije na život u špilji. Razlike su očite i među rodovima i špiljskim vrstama koje su na istom stupnju adaptacije. Glavne modifikacije tiču se oblika i strukture različitih dijelova, kao i njihove duljine, i rasporeda dlaka, čekinja i seta. Prilagodba na akvatičku prehrambenu nišu modificirala je čeljusti, koje su dobile oblik žlice kojom se voda prinosi ustima; lacinia preuzima ulogu miješanja, a galea filtriranja organskih čestica svojim finim i vrlo gustim dlačicama. Očita jednoličnost uvjeta u podzemnom okolišu, te izvora hrane, zajedno s njenom rijetkošću, mogu pogrešno upućivati na jednosmjernu evoluciju stanovnika podzemlja. Uočene razlike između usnih organa proučavanih vrsta mogu biti dobar materijal za taksonomiste koji neke od tih osobina mogu uključiti u svoj rad, obično težak zbog homogene morfologije mnogih stanovnika podzemlja. Kao doprinos komparativnoj studiji usnih organa nekih predstavnika holevina, na temelju usnih organa naglašavamo efekt prilagodbe na špiljski život te dokaz divergentne evolucije u relativno konstantnom okolišu, u smislu klime i dotoka hrane

Retrieval behavior and thermodynamic properties of symmetrically diluted Q-Ising neural networks

The retrieval behavior and thermodynamic properties of symmetrically diluted Q-Ising neural networks are derived and studied in replica-symmetric mean-field theory generalizing earlier works on either the fully connected or the symmetrical extremely diluted network. Capacity-gain parameter phase diagrams are obtained for the Q=3, Q=4 and $Q=\infty$ state networks with uniformly distributed patterns of low activity in order to search for the effects of a gradual dilution of the synapses. It is shown that enlarged regions of continuous changeover into a region of optimal performance are obtained for finite stochastic noise and small but finite connectivity. The de Almeida-Thouless lines of stability are obtained for arbitrary connectivity, and the resulting phase diagrams are used to draw conclusions on the behavior of symmetrically diluted networks with other pattern distributions of either high or low activity.Comment: 21 pages, revte

Iron Status and Analysis of Efficacy and Safety of Ferric Carboxymaltose Treatment in Patients with Inflammatory Bowel Disease

Background and Aims:We analyzed iron deficiency and the therapeutic response following intravenous ferric carboxymaltose in a large single-center inflammatory bowel disease (IBD) cohort. Methods: 250 IBD patients were retrospectively analyzed for iron deficiency and iron deficiency anemia. A subgroup was analyzed regarding efficacy and side effects of iron supplementation with ferric carboxymaltose. Results: In the cohort (n = 250), 54.4% of the patients had serum iron levels 60 mu g/dl, 61.6% had ferritin >100 ng/ml, and 90.7% reached Hb >12/13 g/dl at follow-up (p < 0.0001 for all parameters vs. pretreatment values). The most frequent adverse event was a transient increase of liver enzymes with male gender as risk factor (p = 0.008, OR 8.62, 95% CI 1.74-41.66). Conclusions: Iron deficiency and anemia are frequent in IBD patients. Treatment with ferric carboxymaltose is efficious, safe and well tolerated in iron-deficient IBD patients. Copyright (C) 2011 S. Karger AG, Base