In this paper, systems formed by networks of simple nonlinear cells are studied. Using lattice models, some of the fundamental features of complex systems such as self-organization and pattern formation are illustrated. In the first part of this work, a lattice of identical Chua’s circuit is used to experimentally study its global spatiotemporal dynamics, according to the variation of some macr...

Neural networks can be classified into recurrent and nonrecurrent categories. Nonrecurrent (feedforward) networks have no feedback elements; the output is calculated directly from the input through feedforward connections. In recurrent networks the output depends not only on the current input to the network, but also on the current or previous outputs or states of the network. For this reason, ...

We exactly solve a class of Frenkel-Kontorova models with a periodic potential composed of piecewise convex parabolas having the same curvature. All rotationally ordered stable configurations can be depicted with appropriate phase parameters. The elements of a phase parameter are grouped into subcommensurate clusters. Phase transitions, manifested in the gap structure changes previously seen in...

Let Ω be an invariant nonrecurrent Fatou component associated with the automorphism F : C → C. Assume that all of the limit maps of {F|Ω} are constant. We prove the following theorem. If there is more than one such limit map then there are uncountably many. The images of these limit maps form a closed set in the boundary of Ω containing no isolated points. Additionally there cannot be more than...

OBJECTIVE To determine the role of angiogenesis in the clinical behavior and pathogenesis of lymphangioma tumors. DESIGN A retrospective study. Median follow-up period was 44.5 months. SETTING Children's Memorial Hospital, Chicago, Ill. PATIENTS Tumor specimens from 12 pediatric patients who underwent surgical excision of cervicofacial lymphangioma were examined for expression of angiogen...

Let {Xi},i = l, • • • , be a sequence of independent and identically distributed random variables with density function f(x). We shall assume throughout that EXi=p>0. Let {Sn}, n = l, • • • , be the sequence of cumulative sums Sn= 23"-1 -^«'Let H(x) = 23»= i P(Sn ^x) and h(x)=H'(x). Since H(x) is nondecreasing, h(x) is defined for almost all x. Let A be any Borel set of positive real numbers an...

Recurrence equations for the number of types and the frequency of each type in a random sample drawn from a finite population undergoing discrete, nonoverlapping generations and reproducing according to the Cannings exchangeable model are deduced under the assumption of a mutation scheme with infinitely many types. The case of overlapping generations in discrete time is also considered. The equ...

We reviewed the records of all patients in the intensive care unit (ICU) who had Pseudomonas aeruginosa pneumonia over a 2.5-year period. Of patients with P aeruginosa pneumonia, 20 of 34 survived the initial episode of pneumonia. Ten of these 20 developed recurrence. In the nonrecurrent group, nine of ten survived hospitalization, compared to only four of ten in the recurrent group. Comparing ...