A frequency measure robust to linear filtering

A definition of frequency (cycles per unit-time) based on an approximate reconstruction of the phase-space trajectory of an oscillator from a signal is introduced. It is shown to be invariant under linear filtering, and therefore inaccessible by spectral methods. The effect of filtering on frequency in cases where this definition does not perfectly apply is quantified.Comment: 10 pages, 2 figure

Stochastic to deterministic crossover of fractal dimension for a Langevin equation

Using algorithms of Higuchi and of Grassberger and Procaccia, we study numerically how fractal dimensions cross over from finite-dimensional Brownian noise at short time scales to finite values of deterministic chaos at longer time scales for data generated from a Langevin equation that has a strange attractor in the limit of zero noise. Our results suggest that the crossover occurs at such short time scales that there is little chance of finite-dimensional Brownian noise being incorrectly identified as deterministic chaos.Comment: 12 pages including 3 figures, RevTex and epsf. To appear Phys. Rev. E, April, 199

On the Co-Relation of Various Diseases in Stock in South Africa

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Dynamics of plasma blobs in a shear flow

The global dynamic of plasma blobs in a shear flow is investigated in a simple magnetized torus using the spatial Fourier harmonics (k-space) framework. Direct experimental evidence of a linear drift in k space of the density fluctuation energy synchronized with blob events is presented. During this drift, an increase of the fluctuation energy and a production of the kinetic energy associated with blobs are observed. The energy source of the blob is analyzed using an advection-dissipation-type equation that includes blob-flow exchange energy, linear drift in k space, nonlinear processes, and viscous dissipations. We show that blobs tap their energy from the dominant E B vertical background flow during the linear drift stage. The exchange of energy is unidirectional as there is no evidence that blobs return energy to the flow

Test your surrogate data before you test for nonlinearity

The schemes for the generation of surrogate data in order to test the null hypothesis of linear stochastic process undergoing nonlinear static transform are investigated as to their consistency in representing the null hypothesis. In particular, we pinpoint some important caveats of the prominent algorithm of amplitude adjusted Fourier transform surrogates (AAFT) and compare it to the iterated AAFT (IAAFT), which is more consistent in representing the null hypothesis. It turns out that in many applications with real data the inferences of nonlinearity after marginal rejection of the null hypothesis were premature and have to be re-investigated taken into account the inaccuracies in the AAFT algorithm, mainly concerning the mismatching of the linear correlations. In order to deal with such inaccuracies we propose the use of linear together with nonlinear polynomials as discriminating statistics. The application of this setup to some well-known real data sets cautions against the use of the AAFT algorithm.Comment: 14 pages, 15 figures, submitted to Physical Review

Emerging Infections and Pregnancy

Immunologic changes of pregnancy may increase susceptibility to certain intracellular pathogens

Primary Care Providers’ Perceptions of Mental and Behavioral Health Problems in Frontier Areas of Idaho

Depression and other significant mental and behavioral health (MBH) problems have not been well documented in frontier areas of Idaho. It has been suggested that residents of frontier areas access their primary care provider (PCP) for most of their general health and MBH needs. To determine PCPs’ perceptions of MBH issues in frontier areas of Idaho, surveys were sent to all 252 PCPs with a registered practice location in one of Idaho’s 26 frontier counties. The survey asked questions regarding the PCPs’ practice history, the percentage of their patients who have an MBH problem and what those MBH problems are, how often they make referrals to MBH care professionals, and if there are barriers to obtaining care, how prepared they feel to identify and treat MBH problems, and whether further training in these areas would be beneficial. Seventy-four PCPs (of the 228 successful mailings) replied to the survey, yielding a response rate of 32.5%, which was proportional to the distribution of the true PCP population and represented all frontier Idaho. It was found that doctors (MDs and DOs) had their professional degree longer and had practiced in a frontier area of Idaho longer than midlevel providers (physician assistants and nurse practitioners). PCPs reported that about 30% percent of their patients may have a MBH problem. Mood disorders, anxiety, and substance abuse were the three most commonly reported MBH problems that PCPs encountered in their clinics. Finances and transportation (88.6% and 71.4%, respectively) were the most frequently reported barriers to obtaining professional MBH care. Finally, although all PCPs reported feeling prepared to identify and treat MBH problems, most reported that additional training in the identification and treatment of MBH problems would be beneficial

Randomized trial comparing the i-gel™ and Magill tracheal tube with the single-use ILMA™ and ILMA™ tracheal tube for fibreoptic-guided intubation in anaesthetized patients with a predicted difficult airway

Background The i-gel™ is a single-use supraglottic airway device (SAD) that allows fibreoptic-guided tracheal intubation through the device. Until now, no prospective data for this procedure are available. Therefore, in a prospective randomized controlled trial, we evaluated fibreoptic-guided tracheal intubation with a standard Rüsch™ PVC tracheal tube (TT) through the i-gel™ compared with the single-use ILMA™ (sILMA™) TT through the sILMA™ in patients with a predicted difficult airway. Methods With ethics committee approval and written informed consent, 160 patients were randomly assigned to either SAD. After placement of the SAD, a fibreoptic bronchoscope was introduced into the trachea as a railroad for the TT. Primary outcome variable was the first-attempt fibreoptic-guided intubation success rate. Secondary variables included time for insertion and intubation, airway leak pressures, fibreoptic view, and adverse events. Data are presented as mean (sd) or percentages. A P-value of <0.05 was considered statistically significant. Results Fibreoptic-guided intubation was successful at the first attempt in 76 patients (96%) using the i-gel™ and in 71 patients (90%) using the sILMA™ (P=0.21). Most of the failed intubations were rescued by conventional laryngoscopy. Airway leak pressure was higher for the sILMA™. There were no problems during removal of either type of SAD. Conclusions Fibreopic-guided tracheal intubation through the i-gel™ using a standard Rüsch™ Magill TT is successful and an alternative to the sILMA™ with the sILMA™ T

Erfahrungen bei der Messung der Ergebnisqualität in der interventionellen Schmerztherapie

BACKGROUND There is a growing interest in patient-related outcome measurement. In this field questionnaires on touch screens are becoming more common. This study was designed to identify problems in usability and feasibility of a web-based questionnaire. STUDY PARTICIPANTS AND METHODS Patients who underwent a lumbar infiltration were recruited in 5 centers and 50 patients participated of which half were older than 62 years. One third of the patients had basically no former experience with computers or touch screens. The outcome was assessed before treatment and during follow-up on a simple web-based patient questionnaire, the Activity Index. Results were presented graphically and discussed during consultation. Patients, nurses and doctors were asked for standardized feedback. RESULTS Of the patients 84% completed the questionnaire in up to 6 min. An adapted form of the system usability scale (SUS) achieved an acceptance score of 71.8%. Problems in handling occurred mostly in older patients (>65 years). The system was scored with 72.9% and 78.5% in efficiency and handling, respectively, by the nurses. The attending physicians rated the usefulness and comprehensibility of the graphical representation of the results on average as 83.3% and both were scored neutral to positive; however, an average of 11.6% rated some aspects of the report to be suboptimal. CONCLUSION This web-based questionnaire is the first of its kind to be evaluated in everyday practice of interventional pain therapy for lumbar back pain. The vast majority of the patients were able to efficiently complete the questionnaire. The questionnaire was highly acceptable to patients, nurses and doctors. We found some usability problems but mainly in the older age group