Poles, Shocks and Tygers: The Time-reversible Burgers Equation

We construct a formally time-reversible, one-dimensional forced Burgers equation by imposing a global constraint of energy conservation, wherein the constant viscosity is modified to a fluctuating state-dependent dissipation coefficient. The new system exhibits dynamical properties which bear strong similarity with those observed for the Burgers equation and can be understood using the dynamics of the poles, shocks and truncation effects such as tygers. A complex interplay of these give rise to interesting statistical regimes ranging from hydrodynamic behaviour to a completely thermalized warm phase. The end of the hydrodynamic regime is associated with the appearance of a shock in the solution and a continuous transition leading to a truncation dependent state. Beyond this, the truncation effects such as tygers and appearance of secondary discontinuity at the resonance point in the solution strongly influence the statistical properties. These disappear at the second transition, at which the global quantities exhibit a jump and attain values that are consistent with the establishment of a 'quasi-equilibrium' state characterized by energy equipartition among the Fourier modes. Our comparative analysis shows that the macroscopic statistical properties of the formally time-reversible system and the Burgers equation are equivalent in all the regimes, irrespective of the truncation effects, and this equivalence is not just limited to the hydrodynamic regime, thereby further strengthening the Gallavotti's equivalence conjecture. The properties of the system are further examined by inspecting the complex space singularities in the velocity field of the Burgers equation. Furthermore, an effective theory is proposed to describe the discontinuous transition.Comment: 25 pages, 18 figure

Circular string in a Black p-brane leading to chaos

We consider a pulsating string near a non-extremal black p-brane (p=5 and p=6) and investigate the chaos in the corresponding string dynamics by examining the Fast Lyapunov indicator(FLI) and Poincare section. In our system, the energy and the charge play the role of control parameters. For generic values of these parameters, the numerical results show that the dynamics primarily fall into three modes: capture, escape to infinity, and quasiperiodic depending on the initial location (near to or far away from the black brane horizon) of the string. Finally, probing for different values of the winding number (n) the dynamics turns out to be sensitive to n. In particular, we observe the point particle (n=0) scenario to be integrable whereas at higher n the dynamics seems to be chaotic.Comment: 21 pages, 40 figure

An elasto-plastic approach based on microscopic insights for the steady state and transient dynamics of sheared disordered solids

In this letter, we develop a framework to study the mechanical response of athermal amorphous solids via a coupling of mesoscale and microscopic models. Using measurements of coarse grained quantities from simulations of dense disordered particulate systems, we present a coherent elasto-plastic model approach for deformation and flow of yield stress materials. For a given set of parameters, this model allows to match consistently transient and steady state features of driven disordered systems under both applied shear-rate and creep protocols

In Situ Studies of the Primary Immune Response to (4-Hydroxy-3-Nitrophenyl)Acetyl. V. Affinity Maturation Develops in Two Stages of Clonal Selection

To examine the role of germinal centers (GCs) in the generation and selection of high affinity antibody-forming cells (AFCs), we have analyzed the average affinity of (4-hydroxy-3-nitrophenyl)acetyl (NP)-specific AFCs and serum antibodies both during and after the GC phase of the immune response. In addition, the genetics of NP-binding AFCs were followed to monitor the generation and selection of high affinity AFCs at the clonal level. NP-binding AFCs gradually accumulate in bone marrow (BM) after immunization and BM becomes the predominant locale of specific AFCs in the late primary response. Although the average affinity of NP-specific BM AFCs rapidly increased while GCs were present (GC phase), the affinity of both BM AFCs and serum antibodies continued to increase even after GCs waned (post-GC phase). Affinity maturation in the post-GC phase was also reflected in a shift in the distribution of somatic mutations as well as in the CDR3 sequences of BM AFC antibody heavy chain genes. Disruption of GCs by injection of antibody specific for CD154 (CD40 ligand) decreased the average affinity of subsequent BM AFCs, suggesting that GCs generate the precursors of high affinity BM AFCs; inhibition of CD154-dependent cellular interactions after the GC reaction was complete had no effect on high affinity BM AFCs. Interestingly, limited affinity maturation in the BM AFC compartment still occurs during the late primary response even after treatment with anti-CD154 antibody. Thus, GCs are necessary for the generation of high affinity AFC precursors but are not the only sites for the affinity-driven clonal selection responsible for the maturation of humoral immune responses

TRADITIONAL BONE SETTING PRACTICE OF RABHA PEOPLE OF ASSAM

Objective: The aim of this work is to document the various ethnomedicinal healing plant species used in traditional bone setting (TBS) practice of Rabha community of Assam.Methods: This has been done using interview method which includes semi-structured questionnaire and the field walks method.Results: The results reveal that eight healing plants wear employed to in the TBS practice. Among these, Cissus quadrangularis L. is the most commonly used plant species to treat bone fracture. In this study, two modes of preparation for the ethnomedicine have been served (i.e., paste and extract) where paste form has higher used (75%).Conclusions: It has been concluded that Rabha Hasong area of Assam is indeed rich in ethnomedicinal plants. People get benefited from the traditional practices performed by the medicine men. This is the chief reason TBS practice that is still running smoothly with full faith and hope even in the current time where sophisticated orthopedic treatments are obtainable. Moreover, systematic nutraceutical appraisal of these species would provide a remarkable research possibility in the fields of ethnopharmacology that would be useful in the modern orthopedic treatments

Predictors of outcome in myxoedema coma: a study from a tertiary care centre

BACKGROUND: With the easy availability of thyroid hormone assays, thyroid disorders are now recognised even in a subclinical state. However, patients are still seen with advanced manifestations of the disease, particularly in developing countries. This observational study analysed the predictors of outcome in patients with myxoedema coma and tested the validity of different modules to define morbidity and mortality in these patients. METHODS: Twenty-three consecutive patients with myxoedema coma who presented from January 1999 to August 2006 were studied. The thyroid function test and random serum cortisol were measured in all patients at the time of admission. Patients were given oral or intravenous (i.v.) thyroxine with intention to treat with the latter according to availability. Various modules that predict outcome, including Glasgow Coma Scale (GCS), Acute Physiology and Chronic Health Evaluation II (APACHE II) score, and Sequential Organ Failure Assessment (SOFA) score, were analysed. SOFA score was repeated every 2 days until the time of discharge or demise. RESULTS: Twenty-three patients (20 women; 87%) of 59.5 +/- 14.4 years of age (range, 30 to 89 years) were seen during the study period. Nine (39%) patients were diagnosed with hypothyroidism for the first time at the time of presentation of myxoedema coma, whereas 14 (70%) were diagnosed with hypothyroidism previously. However, the treatment defaulters presented early to the hospital and had more severe manifestations than de novo subjects. Nineteen (82%) had thyroprivic (primary) and 4 (17%) had trophoprivic (secondary) hypothyroidism. Fifteen (65%) patients presented in the winter and in 17 (74%) sepsis was the major accompanying comorbidity. Twelve (52%) had a history of diuretic use, thereby delaying the initial diagnosis. Patients who received oral L-thyroxine had no difference in outcome from those receiving i.v. thyroxine. Twelve (52%) subjects died and sepsis was the predominant cause of death. Various predictors of mortality included hypotension (p = 0.01) and bradycardia (p = 0.03) at presentation, need for mechanical ventilation (p = 0.00), hypothermia unresponsive to treatment (p = 0.01), sepsis (p = 0.01), intake of sedative drugs (p = 0.02), lower GCS (p = 0.03), high APACHE II score (p = 0.04), and high SOFA score (p = 0.00). However, SOFA score was more effective than other predictive models as baseline and day 3 SOFA scores of more than 6 were highly predictive of poor outcome. CONCLUSION: L-Thyroxine treatment defaulters had more severe manifestations compared with de novo subjects. Outcome was not influenced by either aetiology or route of administration of L-thyroxine, and SOFA score was the best outcome predictor model

Low-Abundance Members of the Firmicutes Facilitate Bioremediation of Soil Impacted by Highly Acidic Mine Drainage From the Malanjkhand Copper Project, India

Sulfate- and iron-reducing heterotrophic bacteria represented minor proportion of the indigenous microbial community of highly acidic, oligotrophic acid mine drainage (AMD), but they can be successfully stimulated for in situ bioremediation of an AMD impacted soil (AIS). These anaerobic microorganisms although played central role in sulfate- and metal-removal, they remained inactive in the AIS due to the paucity of organic carbon and extreme acidity of the local environment. The present study investigated the scope for increasing the abundance and activity of inhabitant sulfate- and iron-reducing bacterial populations of an AIS from Malanjkhand Copper Project. An AIS of pH 3.5, high soluble SO42− (7838 mg/l) and Fe (179 mg/l) content was amended with nutrients (cysteine and lactate). Thorough geochemical analysis, 16S rRNA gene amplicon sequencing and qPCR highlighted the intrinsic metabolic abilities of native bacteria in AMD bioremediation. Following 180 days incubation, the nutrient amended AIS showed marked increase in pH (to 6.6) and reduction in soluble -SO42− (95%), -Fe (50%) and other heavy metals. Concomitant to physicochemical changes a vivid shift in microbial community composition was observed. Members of the Firmicutes present as a minor group (1.5% of total community) in AIS emerged as the single most abundant taxon (∼56%) following nutrient amendments. Organisms affiliated to Clostridiaceae, Peptococcaceae, Veillonellaceae, Christensenellaceae, Lachnospiraceae, Bacillaceae, etc. known for their fermentative, iron and sulfate reducing abilities were prevailed in the amended samples. qPCR data corroborated with this change and further revealed an increase in abundance of dissimilatory sulfite reductase gene (dsrB) and specific bacterial taxa. Involvement of these enhanced populations in reductive processes was validated by further enrichments and growth in sulfate- and iron-reducing media. Amplicon sequencing of these enrichments confirmed growth of Firmicutes members and proved their sulfate- and iron-reduction abilities. This study provided a better insight on ecological perspective of Firmicutes members within the AMD impacted sites, particularly their involvement in sulfate- and iron-reduction processes, in situ pH management and bioremediation