We study the existence of strange nonchaotic attractors (SNA) in the family of Harper maps. We prove that for a set of parameters of positive measure, the map possesses a SNA. However, the set is nowhere dense. By changing the parameter arbitrarily small amounts, the attractor is a smooth curve and not a SNA.

Spontaneous fluctuations (SF) in skin conductance are often used to index sympathetic arousal and emotional states. SF are caused by sudomotor nerve activity (SNA), which is a direct indicator of sympathetic arousal. Here, we describe a dynamic causal model (DCM) of how SNA causes SF, and apply variational Bayesian model inversion to infer SNA, given empirically observed SF. The estimated SNA b...

The study of collaborative action under a situated perspective demands the adoption of an interpretative framework in which social network analysis (SNA) is combined with other methods of analysis, in order to gain insight into the processes being studied. Additionally, the complexity of CSCW situations demands the use of distinct sources of data as the input of the analysis. We introduce our p...

The successful adaptation of telephone networks to data transmission has fostered two decades of rapid growth in data processing systems using telecommunications facilities. To augment the telephony base, new public networks are now being designed specifically for data communications. The international scope and technological aspects of these new services have been described elsewhere in this i...

A controversial issue in exercise physiology is the relative contribution of central command versus afferent input from contracting muscles and baroreceptors in the regulation of sympathetic nerve activity (SNA) during exercise. Recent studies of exercising humans have suggested that central command increases cutaneous sympathetic sudomotor nerve activity but have challenged the concept that ce...

Salivary gland function is regulated by both the sympathetic and parasympathetic nervous systems. Previously we showed that the basal sympathetic outflow to the salivary glands (SNA(SG)) was higher in hypertensive compared to normotensive rats and that diabetes reduced SNA(SG) discharge at both strains. In the present study we sought to investigate how SNA(SG) might be modulated by acute change...

OBJECTIVES Among patients with HIV, the risk of death associated with different AIDS events has been quantified, but the risk of death associated with non-AIDS events has not been examined. We compared the risk of all-cause mortality following AIDS versus serious non-AIDS (SNA) events in the Strategies for Management of Antiretroviral Therapy (SMART) study and the Evaluation of Subcutaneous Pro...

Morgan DA, Thedens DR, Weiss R, Rahmouni K. Mechanisms mediating renal sympathetic activation to leptin in obesity. Am J Physiol Regul Integr Comp Physiol 295: R1730–R1736, 2008. First published September 24, 2008; doi:10.1152/ajpregu.90324.2008.— Leptin plays a critical role in the control of energy homeostasis. The sympathetic cardiovascular actions of leptin have emerged as a potential link ...

PURPOSE This study aimed to evaluate the efficacy, safety, and pharmacokinetics of 20 and 40 mg/day conivaptan (Vaprisol®) in patients with hypervolemic or euvolemic hyponatremia. METHODS Hyponatremic patients - serum sodium (sNa) ≤130 mEq/L - received either 20 or 40 mg/day of conivaptan for 4 days, following an initial 20 mg loading dose. Efficacy was evaluated by the magnitude and extent o...

Leptin plays a critical role in the control of energy homeostasis. The sympathetic cardiovascular actions of leptin have emerged as a potential link between obesity and hypertension. We previously demonstrated that in mice, modest obesity induced by 10 wk of a high-fat diet is associated with preservation of leptin ability to increase renal sympathetic nerve activity (SNA) despite the resistanc...