Chaotic and pseudochaotic attractors of perturbed fractional oscillator

We consider a nonlinear oscillator with fractional derivative of the order alpha. Perturbed by a periodic force, the system exhibits chaotic motion called fractional chaotic attractor (FCA). The FCA is compared to the ``regular'' chaotic attractor. The properties of the FCA are discussed and the ``pseudochaotic'' case is demonstrated.Comment: 20 pages, 7 figure

Pediatric pacemaker infections: Twenty years of experience

AbstractObjective: We sought to evaluate possible predictors of early and late pacemaker infections in children. Methods: A review was performed of all pacemakers implanted in children at The Children's Hospital of Philadelphia between 1982 and 2001. Infections were classified as superficial cellulitus, deep pacemaker pocket infection necessitating removal, or positive blood culture without an identifiable source. Results: A total of 385 pacemakers (224 epicardial and 161 endocardial) were implanted in 267 patients at 8.4 ± 6.2 years. All 2141 outpatient visits were reviewed (median follow-up, 29.4 months; range, 2-232 months). There were 30 (7.8%) pacemaker infections: 19 (4.9%) superficial infections; 9 (2.3%) pocket infections; and 2 (0.5%) isolated positive blood cultures. All superficial infections resolved with intravenous antibiotics. The median time from implantation to infection was 16 days (range, 2 days-5 years). Only 1 deep infection occurred after primary pacemaker implantation. Six patients with deep infections were pacemaker dependent and were successfully managed with intravenous antibiotics, followed by lead-generator removal and implantation of a new pacemaker in a remote location. In univariate analyses trisomy 21 (relative risk, 3.9; P <.01), pacemaker revisions (relative risk, 2.5; P <.01), and single-chamber devices (relative risk, 2.4; P <.05) were identified as predictors of infection. However, in multivariate analyses only trisomy 21 and pacemaker revisions were predictors. Conclusions: The incidences of superficial and deep pacemaker infections were 4.9% and 2.3%, respectively. Trisomy 21 and pacemaker revisions were significant risk factors in the development of infection after pacemaker implantation. For primary pacemaker implantation, the risk of infection requiring system removal is low (0.3%).J Thorac Cardiovasc Surg 2002;124:821-

Relationship between Tibial conformation, cage size and advancement achieved in TTA procedure

Previous studies have suggested that there is a theoretical discrepancy between the cage size and the resultant tibial tuberosity advancement, with the cage size consistently providing less tibial tuberosity advancement than predicted. The purpose of this study was to test and quantify this in clinical cases. The hypothesis was that the advancement of the tibial tuberosity as measured by the widening of the proximal tibia at the tibial tuberosity level after a standard TTA, will be less than the cage sized used, with no particular cage size providing a relative smaller or higher under-advancement, and that the conformation of the proximal tibia will have an influence on the amount of advancement achieved

Effect of Spirulina platensis supplementation on growth, performance and body conformation of two Omani goat breeds

Context: Spirulina platensis (SP) has been found to be an important dietary supplement for boosting animal growth performance, having a high protein content (60–70% on a dry-matter basis) with minimal toxicity. Aims: The effect of Spirulina platensis (SP) supplementation on the growth and performance of two Omani goat breeds (Jabbali and Sahrawi) was investigated. Methods: Thirty-six 11-month-old bucks from two Omani goat breeds were studied for 70 days at the Livestock Research Centre, Ministry of Agriculture, Fisheries and Water Resources, Oman. Each breed was divided into three groups (n = 6) and fed one of the following three rations: (1) control (CON): concentrate with 14% crude protein and 11.9% energy (MJ/kg DM); (2) Treatment 1 (T1): the same concentrate with 2 g/head.day SP; and (3) Treatment 2 (T2): the same concentrate with 4 g/head.day SP. Weekly growth, performance and body conformation data collected included live bodyweight (BWT), body condition score (BCS), average daily gain (ADG), chest girth (CG), wither height (WH) and body length (BL). Key results: The Jabbali breed had a higher feed conversion ratio for T1 and T2 than did the Sahrawi breed. During the trial, no differences in total DM intake were found between treatments for either breed. T1 and T2 SP supplementation levels significantly (P 0.05) for any of the studied traits. However, the breed effect was highly significant (P < 0.001) on BWT, ADG, BCS and treatment effect was significant (P < 0.05) on CG traits. Conclusions: Spirulina platensis could be used as a supplement feed to improve growth, performance and morphological traits in Omani goat production. Feeding spirulina to kids led to increased growth, herd performance and buck selection facilitation at an earlier age. Implications: These findings will benefit Omani goat producers in managing productivity and product quality

paediatric respiratory disease past present and future

Paediatric respiratory disease has changed in the past 20 yrs; we could fill a whole issue of the journal paying tribute to our famous forebears. We are posing new challenges to our colleagues in the field of adult respiratory disease. They have to learn to deal with conditions that 20 yrs ago were rare in the adult chest clinic, such as cystic fibrosis (CF) and the long-term consequences of premature birth and congenital malformations of the respiratory tract. Furthermore, studies in childhood are challenging pathophysiological concepts throughout life. The many great prospective birth cohort studies have shed light on the different patterns of wheezing, their risk factors and their evolution through childhood. Who would have thought it was good to be born in a barn! It is becoming increasingly clear that even for "adult" diseases, such as chronic obstructive pulmonary disease (COPD), antenatal and early life events are at least as important as smoking in adulthood 1. CF has become a disease also of adults 2. Although many factors have contributed, the main reason has been the development of expert special CF centres, a model increasingly adopted by adult teams. This can serve as a model for other diseases; how a well-structured multidisciplinary approach to treatment can translate into benefits for patients. Perhaps numerically the most important achievement is in the field of public health. The benefit of the decrease in invasive bacterial infections, due to vaccination programmes for infants, is among the most important achievements of the past. Other areas of change include the survival of ever smaller preterm neonates. These children are reaching adult life with impaired lung function and abnormal computed tomography scans. What will happen to their ageing lungs? Interstitial lung disease (ILD) is becoming increasingly well understood, with new genetic entities, such as