3,146 research outputs found
Collective patterns arising out of spatio-temporal chaos
We present a simple mathematical model in which a time averaged pattern
emerges out of spatio-temporal chaos as a result of the collective action of
chaotic fluctuations. Our evolution equation possesses spatial translational
symmetry under a periodic boundary condition. Thus the spatial inhomogeneity of
the statistical state arises through a spontaneous symmetry breaking. The
transition from a state of homogeneous spatio-temporal chaos to one exhibiting
spatial order is explained by introducing a collective viscosity which relates
the averaged pattern with a correlation of the fluctuations.Comment: 11 pages (Revtex) + 5 figures (postscript
The Breakdown of Synchronization in Systems of Non-identical Chaotic Oscillators: Theory and Experiment
The synchronization of chaotic systems has received a great deal of attention. However, most of the literature has focused on systems that possess invariant manifolds that persist as the coupling is varied. In this paper, we describe the process whereby synchronization is lost in systems of nonidentical coupled chaotic oscillators without special symmetries. We qualitatively and quantitatively analyze such systems in terms of the evolution of the unstable periodic orbit structure. Our results are illustrated with data from physical experiments
Gender Differences in Takotsubo Cardiomyopathy as a Secondary Diagnosis: Higher Hospital Charges, More Procedures, and Longer Length of Stays
Background The incidence of Takotsubo Cardiomyopathy (TC) has risen steadily over the past decade, with current estimates of 15-30 cases per 100,000 per year. Historically, men diagnosed with TC have worse outcomes compared to women. The relationship between total hospital charges, number of procedures performed, and length of stay (LOS) between genders has not been previously reported with TC as a secondary diagnosis. Methods National Inpatient Sample (NIS) data from 2009-2015 was used to identify encounters of adult patients (â„18 years) undergoing coronary angiography that were ultimately given a secondary diagnosis of TC (International Classification of Diseases â 9 code 429.83). Demographics, comorbidities and outcomes including hospital mortality, total charges, and LOS were assessed and stratified by gender. Continuous variables were described using means and compared using independent two-sample t-tests. Total charges and LOS were described using medians and compared using Wilcoxon rank sum test. TC encounters were propensity matched by age, number of chronic conditions, number of procedures performed, and severity of illness. A discharge weight was included in all analyses to account for the complex sample design of the NIS. Results
During 2009-2015, 1,448 men and 9,404 women with secondary TC were identified in the dataset, corresponding to a national estimate of 7,124 men and 46,163 women. The median hospital charges were 45,455 for women (p Conclusion Compared to women, men with a secondary diagnosis of TC are more likely to have a greater number of procedures, leading to a longer LOS and âŒ$10,000 more in hospital charges. Greater awareness of TC as a potential secondary diagnosis is warranted among men
How physicians caring for adult patients presenting a chronic mental disturbance take account of the difficulties their patientsâ children under 18: Preliminary study
AbstractAimsTo study how physicians caring for adult patients presenting a chronic mental disturbance take account of the difficulties of their patientsâ children under 18.MethodExploratory and qualitative study based on an in-depth study of interviews.Study populationThirteen physiatrists or neurologists following brain-damaged patients and 12 psychiatrists following patients with chronic psychiatric disorders.ResultsIn the two groups of physicians, diversified practices in catering for the issues of the patient's parenthood, childâparent relationships, and difficulties experienced by the child. The child's difficulties are not approached as such. For many of the physicians, representations of the parenting function, and of the child's needs and difficulties are not often used in work with the patient. Patient-centred care appears at odds with catering for the patient's children and their specific difficulties. The seriousness of the mental pathologies, their chronic nature, and the fact that they can affect the patient in his/her parental functioning and concerns, appear as factors in the reluctance of physicians. Other reasons are lack of familiarity with issues relating to childhood, and the feeling of encroaching on a private and intimate sphere. The representations of physicians with regard to parenthood, parentâchild relations, and the needs and difficulties of children, are often not integrated into the corpus of knowledge. These issues are more often aspects of physiciansâ own experience.ConclusionThe conflict of values and the uneasiness of the physicians suggest the need for ethical reflection groups or Balint groups
Stochastic synchronization in globally coupled phase oscillators
Cooperative effects of periodic force and noise in globally Cooperative
effects of periodic force and noise in globally coupled systems are studied
using a nonlinear diffusion equation for the number density. The amplitude of
the order parameter oscillation is enhanced in an intermediate range of noise
strength for a globally coupled bistable system, and the order parameter
oscillation is entrained to the external periodic force in an intermediate
range of noise strength. These enhancement phenomena of the response of the
order parameter in the deterministic equations are interpreted as stochastic
resonance and stochastic synchronization in globally coupled systems.Comment: 5 figure
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