Can coarse-graining introduce long-range correlations in a symbolic sequence?

We present an exactly solvable mean-field-like theory of correlated ternary sequences which are actually systems with two independent parameters. Depending on the values of these parameters, the variance on the average number of any given symbol shows a linear or a superlinear dependence on the length of the sequence. We have shown that the available phase space of the system is made up a diffusive region surrounded by a superdiffusive region. Motivated by the fact that the diffusive portion of the phase space is larger than that for the binary, we have studied the mapping between these two. We have identified the region of the ternary phase space, particularly the diffusive part, that gets mapped into the superdiffusive regime of the binary. This exact mapping implies that long-range correlation found in a lower dimensional representative sequence may not, in general, correspond to the correlation properties of the original system.Comment: 10 pages including 1 figur

A growth walk model for estimating the canonical partition function of Interacting Self Avoiding Walk

We have explained in detail why the canonical partition function of Interacting Self Avoiding Walk (ISAW), is exactly equivalent to the configurational average of the weights associated with growth walks, such as the Interacting Growth Walk (IGW), if the average is taken over the entire genealogical tree of the walk. In this context, we have shown that it is not always possible to factor the the density of states out of the canonical partition function if the local growth rule is temperature-dependent. We have presented Monte Carlo results for IGWs on a diamond lattice in order to demonstrate that the actual set of IGW configurations available for study is temperature-dependent even though the weighted averages lead to the expected thermodynamic behavior of Interacting Self Avoiding Walk (ISAW).Comment: Revised version consisting of 12 pages (RevTeX manuscript, plus three .eps figure files); A few sentences in the second paragraph on Page 4 are rewritten so as to make the definition of the genealogical tree, ${\cal Z}_N$, clearer. Also, the second equality of Eq.(1) on Page 4, and its corresponding statement below have been remove

Attenuation of hemodynamic responses to tracheal Extubation: comparison of Diltiazem, Lignocaine and Diltiazem-lignocaine combination

INTRODUCTION: Tracheal intubation as well as extubation often provoke significant cardiovascular changes with marked increase in heart rate and blood pressure. These hemodynamic changes during extubation are probably of little consequence in healthy individuals but may be more severe and more dangerous in hypertensive patients. Hemodynamic changes during extubation and emergence from anaesthesia may cause dangerous increase in myocardial oxygen demand in patients with coronary artery disease and in those with risk factors for CAD. Several drugs like lignocaine, esmolol, alfentanil, fentanyl, prostaglandin E1 and diltiazem are used to attenuate the cardiovascular responses to tracheal extubation in normotensive patients. Diltiazem a calcium channel blocker has been used extensively to maintain perioperative hemodynamic stability. This drug is effective in blunting the hemodynamic changes associated with laryngoscopy and tracheal intubation. The exact mechanism whereby tracheal intubation and extubation cause hemodynamic changes may be different and remain as yet to be elucidated. Tracheal intubation produces a profound but short uniform stimulation in the anaesthetized patient. But during tracheal extubation stimulation which affects the hemodynamic changes is multifactorial; e.g., pain of the wound, emergence from anaesthesia and tracheal irritation. Even if a drug is used effectively to control cardiovascular changes during tracheal intubation, its dose and timing of dosing most probably are different during extubation. Because the pharmacological mechanism for the control of the hemodynamic changes during extubation is thought to differ between diltiazem and lignocaine, combining these two drugs may be more effective than giving each drug alone for attenuating cardiovascular responses. The present study was undertaken to compare the efficacy of diltiazem along with lignocaine with each drug given alone in suppressing the hemodynamic changes during extubation in normotensive patients. After getting approval from the hospital ethical committee, the study was carried out in the Department of Anaesthesiology, Madras Medical College and Government General Hospital, Chennai. AIM OF THE STUDY: The aim of the study is to evaluate the efficacy of combination of diltiazem with lignocaine in suppressing the hemodynamic changes during tracheal extubation and to compare the effects with these drugs given individually. MATERIALS AND METHODS: The study was done to compare the efficacy of combined diltiazem and lignocaine with that of giving each of these drugs separately in suppressing the hemodynamic changes during tracheal extubation in patients posted for elective spine surgeries (lumbar & cervical spine). The study comprised of 60 patients of both sex in the age group of 16 to 60 years. All the patients were informed of the study and prior written informed consent was obtained. The surgeon was also informed about the study. Patients were assessed by a detailed history & physical examination supported by investigations like routine blood tests – Hb, blood sugar, blood urea, serum creatinine, serum electrolytes, chest X-ray PA view and Electrocardiogram. INCLUSION CRITERIA: 1) Patients in ASA Physical Status I & II. 2) Age 16 to 60 years. 3) Patients with modified Mallampatti scores I & II. EXCLUSION CRITERIA: 1) Patients with predicted difficult airway. 2) Patients with co-existing cardio vascular diseases (Hypertension, conduction blocks, Ischaemic heart diease & cardiac failure). 3) Patients on cardiovascular drugs (β-blockers, Calcium channel blockers). 4) Patients with heart rate < 60 beats / min. (hypothyroidism, sinus node disease, other medications). 5) Patients with blood pressure less than 100/60mm Hg. 6) Patients with documented hepatic or renal disease. 7) Pregnant patients. SUMMARY: This prospective randomized study was designed to evaluate the efficacy of combination of diltiazem and lignocaine in suppressing the hemodynamic changes during tracheal extubation. The effect of Diltiazem-Lignocaine combination was compared with that of Diltiazem and Lignocaine given individually. A total of sixty patients belonging to ASA physical status 1 and 2 were randomly divided into three groups. Patients in Group D received Inj.Diltiazem 0.1mg/kg, patients in Group L received Inj.Lignocaine 1.5mg/kg and patients in Group D-L received both Inj.Diltiazem 0.1mg/kg and Inj.Lignocaine 1.5mg/kg. Tracheal extubation was done two minutes after administration of study drug. Changes in heart rate and blood pressure were measured up to five minutes after tracheal extubation. The following observations were made: • Patients in Group D-L showed the maximum attenuation of heart rate and blood pressure changes following tracheal extubation. • Patients in Group D showed a significant increase in heart rate (p < 0.05) after extubation but the increase in blood pressure was not significant. • Patients in Group L showed significant increase in both heart rate and blood pressure following tracheal extubation. • The percentage of patients who had significant coughing and straining during extubation was greater in Group D than in the other two groups. • No patients in any of the three groups developed laryngeal spasm, profound hypotension (SBP < 80mmHg) or bradycardia (HR < 50 bpm). CONCLUSION: From the above study it is concluded that the hemodynamic changes associated with extubation of trachea can be effectively obtunded by using a combination of Diltiazem and Lignocaine than giving each drug separately

Model Adaptation with Synthetic and Real Data for Semantic Dense Foggy Scene Understanding

This work addresses the problem of semantic scene understanding under dense fog. Although considerable progress has been made in semantic scene understanding, it is mainly related to clear-weather scenes. Extending recognition methods to adverse weather conditions such as fog is crucial for outdoor applications. In this paper, we propose a novel method, named Curriculum Model Adaptation (CMAda), which gradually adapts a semantic segmentation model from light synthetic fog to dense real fog in multiple steps, using both synthetic and real foggy data. In addition, we present three other main stand-alone contributions: 1) a novel method to add synthetic fog to real, clear-weather scenes using semantic input; 2) a new fog density estimator; 3) the Foggy Zurich dataset comprising $3808$ real foggy images, with pixel-level semantic annotations for $16$ images with dense fog. Our experiments show that 1) our fog simulation slightly outperforms a state-of-the-art competing simulation with respect to the task of semantic foggy scene understanding (SFSU); 2) CMAda improves the performance of state-of-the-art models for SFSU significantly by leveraging unlabeled real foggy data. The datasets and code are publicly available.Comment: final version, ECCV 201