Dynamics of Crossover from a Chaotic to a Power Law State in Jerky Flow

We study the dynamics of an intriguing crossover from a chaotic to a power law state as a function of strain rate within the context of a recently introduced model which reproduces the crossover. While the chaotic regime has a small set of positive Lyapunov exponents, interestingly, the scaling regime has a power law distribution of null exponents which also exhibits a power law. The slow manifold analysis of the model shows that while a large proportion of dislocations are pinned in the chaotic regime, most of them are pushed to the threshold of unpinning in the scaling regime, thus providing insight into the mechanism of crossover.Comment: 5 pages, 3 figures. In print in Phy. Rev. E Rapid Communication

Study on Comparison Of Three Methods of Gradual Weaning from Mechanical Ventilators

INTRODUCTION: Mechanical ventilation (MV) is a life-supporting modality that is used in a significant proportion of patients in intensive care units , the term mechanical ventilation refers to various artificial means used to support ventilation and oxygenation1, 2 Mechanical ventilation is commonly delivered in intensive care by positive pressure ventilation. Positive pressure ventilation modes are defined by inspiratory events. Expiration is treated as an independent entity. The primary expiratory parameter, positive end expiratory pressure (PEEP) can be applied to any of the ventilator modes. VENTILATOR MODES: The various modes of ventilation are classified based on the types of breaths that are selected. The modes most commonly used in pediatric practice are discussed here. VOLUME TARGETED MODES : 1. Controlled Mechanical Ventilation (CMV): In this mode, the ventilator controls all the ventilation while patient has minimal or no respiratory effort. This is the mode used at the initiation of mechanical ventilation. 2. Assisted Mechanical Ventilation (AMV): All breaths are triggered when the patient’s inspiratory effort exceeds the preset sensitivity threshold of negative pressure. In all other respects, it is similar to controlled mechanical ventilation. 3. Assist Control Ventilation (ACV): ACV is a combination of AMV and CMV. In this mode, the patient initiates the breathing as in AMV. However, if the patients fails to initiate the breathing within a prescribed time the ventilator triggers the breathing and provides a controlled breath as in CMV, thus ensuring a guaranteed minute ventilation. 4. Intermittent Mandatory Ventilation (IMV): It is essentially a combination of spontaneous breathing and CMV. A modified circuit provides a continuous gas flow that allows the patient to breathe spontaneously with minimal work of breathing, At a predetermined frequency, the ventilator provides a positive pressure breath to the patient. 5. Synchronized Intermittent Mandatory Ventilation (SIMV): SIMV allows the patient to trigger a mandatory breath in the assist mode thereby synchronizing it with the patient’s respiratory effort. However, if the patient does not trigger a breath within an allotted time; the ventilator delivers a conventional breath. AIM OF THE STUDY: To assess the effectiveness of the 3 standard methods of weaning from mechanical ventilators namely T – tube weaning, synchronized intermittent mandatory ventilation (SIMV) , continuous positive airway pressure / pressure support ( CPAP/PSV) ventilation in terms of successful weaning, to assess the incidence of weaning failure and duration of weaning with each and also the duration of hospital stay and outcome of these patients so that the best of the weaning procedure can be followed for successful weaning in future. DISCUSSION: In this randomized control trial of comparing the three methods of weaning ( T – piece trial , CPAP / PSV & SIMV ) from mechanical ventilators in children aged 1 month to 12 years , the results were analysed using appropriate statistical tests. In our study weaning was successful as well as duration of weaning was shorter in T – Piece technique than the other two. Intermittent Mandatory Ventilation Several advantages have been claimed for intermittent mandatory ventilation as a weaning technique: it is supposed to prevent a patient from “fighting” the ventilator, reduce respiratory-muscle fatigue, and expedite weaning. However, there are few data to support these claims24,26Intermittent mandatory ventilation is usually delivered in a synchronized manner with demand- valve circuitry, which increases the work of breathing. The intermittent nature of assistance also poses a problem. It was previously assumed that the degree of respiratory-muscle rest was proportional to the level of machine assistance. However, recent evidence indicates that respiratory-sensor output does not adjust to breath-to-breath changes in respiratory load, and intermittent mandatory ventilation may therefore contribute to the development of respiratory muscle fatigue or prevent recovery from it. Studies of the efficacy of intermittent mandatory ventilation in weaning have serious limitations. Schachtern et al44. compared it with conventional ventilation & noted no difference between the two techniques in the duration of ventilator support. Their study suffers from a retrospective design nonuniform study groups, and inadequate description of the protocol. Esteban etal24 compared it with single daily and multiple daily spontaneous breathing trials with t- piece and pressure ventilation and found SIMV as the poorest method of weaning. On comparison with single daily T – piece trial P value was < 0.006. In our study P value was 0.000. SUMMARY AND CONCLUSION: A randomized trial of comparing three methods of weaning from mechanical ventilators was completed in 88 children. From this study we conclude that, 1. Spontaneous extubation during weaning was least with T – piece trial. 2. Duration of weaning & number of trials needed for weaning was least with T - piece trial. 3. Weaning was ~ 6 times faster with T – piece than with CPAP/PSV and ~ 8 times faster than with SIMV. 4. Weaning success was also highest with T – piece trial. 5. Duration of weaning was not significantly different between CPAP/PSV & SIMV group 6. T – piece trial as a technique for weaning of children from mechanical ventilators is the best as far as duration and success of weaning is concerned. This is independent of age or sex or etiology or duration of ventilation prior to weaning or presence of shock or use of inotropes or the underlying disease process

Comparison of Different Orthographies for Machine Translation of Under-Resourced Dravidian Languages

Under-resourced languages are a significant challenge for statistical approaches to machine translation, and recently it has been shown that the usage of training data from closely-related languages can improve machine translation quality of these languages. While languages within the same language family share many properties, many under-resourced languages are written in their own native script, which makes taking advantage of these language similarities difficult. In this paper, we propose to alleviate the problem of different scripts by transcribing the native script into common representation i.e. the Latin script or the International Phonetic Alphabet (IPA). In particular, we compare the difference between coarse-grained transliteration to the Latin script and fine-grained IPA transliteration. We performed experiments on the language pairs English-Tamil, English-Telugu, and English-Kannada translation task. Our results show improvements in terms of the BLEU, METEOR and chrF scores from transliteration and we find that the transliteration into the Latin script outperforms the fine-grained IPA transcription

Production, Characterization and Uses of a Fungal Biopolymer Isolated from Different Sources: A Comparison

Chitin is highly insoluble N - acetylated polymer of β- (1, 4)-D-glucosamine. Chitosan is an acid soluble deacetylated form of chitin. Chitin is commonly found in exoskeleton of marine invertebrates and cuticles of insects. Both chitin and chitosan are also present in the cell wall of most fungi. Chitosan can be obtained by deacetylating chitin prepared from crab or shrimp shell. However, this process fails to produce chitosan of uniform quality. The physicochemical characteristics of chitosan depend on the degree of deacetylation and it also differs, based on the crustacean species and preparation methods used. Chitosan can also be obtained from filamentous fungi. No chemical deacetylation is necessary in this process. As a result, the quality of fungal chitosan is more consistent, inexpensive, eco friendly and chitin and chitosan are extracted simultaneously. Therefore the physicochemical properties and yield of chitosan isolated directly from fungi may be optimized by controlled fermentation. In this work fungal chitosan was prepared from Aspergillus niger, Rhizopus oryzae and Mucor hiemalis without using strong alkaline solution normally used for deacetylation. Fungal chitosan was isolated, with 85-95% degree of deacetylation and viscosity of 13-18 (cP). The profile of both isolated and commercial chitosan showed similar FT-IR and 1HNMR spectra. The antioxidant activity of the isolated chitosan was studied using the stable DPPH (2, 2 diphenyl- picryl- hydrazylhydrate) free radical method. Ascorbic acid was used as standard. The fungal chitosan showed maximum scavenging of DPPH free radicals (EC 50 value was in the range of 3.1- 5.3). The results suggest that chitosan possesses significant in vitro antioxidant activity compared with ascorbic acid. The antibacterial activity of the isolated chitosan was studied by Kirby-Bauer method and it showed good activity against S. aureus, E.coli, including clinical isolate of E.coli

Band filling and interband scattering effects in MgB2_2: C vs Al doping

We argue, based on band structure calculations and Eliashberg theory, that the observed decrease of $T_c$ of Al and C doped MgB$_2$ samples can be understood mainly in terms of a band filling effect due to the electron doping by Al and C. A simple scaling of the electron-phonon coupling constant $\lambda$ by the variation of the density of states as function of electron doping is sufficient to capture the experimentally observed behavior. Further, we also explain the long standing open question of the experimental observation of a nearly constant $\pi$ gap as function of doping by a compensation of the effect of band filling and interband scattering. Both effects together generate a nearly constant $\pi$ gap and shift the merging point of both gaps to higher doping concentrations, resolving the discrepancy between experiment and theoretical predictions based on interband scattering only.Comment: accepted by PR