Glassy swirls of active dumbbells

The dynamics of a dense binary mixture of soft dumbbells, each subject to an active propulsion force and thermal fluctuations, shows a sudden arrest, first to a translational then to a rotational glass, as one reduces temperature $T$ or the self-propulsion force $f$. Is the temperature-induced glass different from the activity-induced glass? To address this question, we monitor the dynamics along an iso-relaxation-time contour in the $(T-f)$ plane. We find dramatic differences both in the fragility and in the nature of dynamical heterogeneity which characterise the onset of glass formation - the activity-induced glass exhibits large swirls or vortices, whose scale is set by activity, and appears to diverge as one approaches the glass transition. This large collective swirling movement should have implications for collective cell migration in epithelial layers.Comment: 13 pages, 11 figure

Active fluidization in dense glassy systems

Dense soft glasses show strong collective caging behavior at sufficiently low temperatures. Using molecular dynamics simulations of a model glass former, we show that the incorporation of activity or self-propulsion, f0, can induce cage breaking and fluidization, resulting in a disappearance of the glassy phase beyond a critical f0 . The diffusion coefficient crosses over from being strongly to weakly temperature dependent as f0 is increased. In addition, we demonstrate that activity induces a crossover from a fragile to a strong glass and a tendency for clustering of active particles. Our results are of direct relevance to the collective dynamics of dense active colloidal glasses and to recent experiments on tagged particle diffusion in living cells.Comment: 8 pages, 9 figure

Activity controls fragility: A Random First Order Transition Theory for an active glass

How does nonequilibrium activity modify the approach to a glass? This is an important question, since many experiments reveal the near-glassy nature of the cell interior, remodelled by activity. However, different simulations of dense assemblies of active particles, parametrised by a self-propulsion force, $f_0$, and persistence time, $\tau_p$, appear to make contradictory predictions about the influence of activity on characteristic features of glass, such as fragility. This calls for a broad conceptual framework to understand active glasses; here we extend the Random First-Order Transition (RFOT) theory to a dense assembly of self-propelled particles. We compute the active contribution to the configurational entropy using an effective medium approach - that of a single particle in a caging-potential. This simple active extension of RFOT provides excellent quantitative fits to existing simulation results. We find that whereas $f_0$ always inhibits glassiness, the effect of $\tau_p$ is more subtle and depends on the microscopic details of activity. In doing so, the theory automatically resolves the apparent contradiction between the simulation models. The theory also makes several testable predictions, which we verify by both existing and new simulation data, and should be viewed as a step towards a more rigorous analytical treatment of active glass

Record of Tropical Rat Mite, Ornithonyssus bacoti (Acari: Mesostigmata: Macronyssidae) from Domestic and Peridomestic Rodents (Rattus rattus) in Nilgiris, Tamil Nadu, India

Background: Tropical rat mite (Ornithonyssus bacoti) is reported from many parts of the world and is considered important in transmitting rickettsial pathogens. There have been scanty reports on prevalence of this parasite from India. Following a recent report of O. bacoti infestation in a laboratory mice colony from Nilgiris, Tamil Nadu, In­dia, attempts were made to detect the parasite in its natural reservoir, ie the domestic and peridomestic rats (Rattus rattus). Methods: The National Centre for Disease Control, Coonoor is involved in screening plague in domestic and peridomestic rats in Nilgiris and erstwhile plague endemic areas of Southern India. The parasite samples were identi­fied based on the morphological characteristics attributable to O. bacoti and as per description of published literature. Results: Seven mite samples identified as O. bacoti based on morphological characteristics were isolated inci­dentally from domestic and peridomestic rodents in and around the hilly districts of Nilgiris, Southern India, during the routine plague surveillance programme. The identification was based on the morphological characteristics at­tributable to O. bacoti observed under a low power microscope. Conclusion: In India, this is probably the first record of isolation of O. bacoti from domestic and peridomestic ro­dents. Prevalence of such parasite in domestic and peridomestic rats necessitates further investigation on monitoring and surveillance of rickettsial diseases in the locality, as these parasites are considered to be potential vector of transmitting rickettsial pathogen

Road traffic accident: An emerging public health problem in Assam

Background: In the northern states, there is hardly any scientific study except road traffic accidents (RTAs) statistics obtained by the Ministry of Home whereas the main way of transportation is by road. There is the increasing load of motor vehicles on the already dilapidated roadways which has resulted in the increasing trend of RTAs in Assam. Objectives: To find out the prevalence, probable epidemiological factors and morbidity and mortality pattern due to RTAs in Dibrugarh district. Materials and Methods: Descriptive study was carried out in Dibrugarh district from September 1998 to August 1999 under the department of Community Medicine. The information was collected from Assam Medical College and Hospital and cross checked with the police report. A medical investigation including interview, clinical and radiological investigation was carried out; in case of fatality, post-mortem examination was examined in details. An on the spot investigation was carried out in accessible RTAs to collect the probable epidemiological factors. Results: RTAs affected mainly the people of productive age group which were predominantly male. Majority of the RTAs were single vehicle accidents and half of the victims were passengers. Accident rate was maximum in twilight and winter season demanding high morbidity and mortality. Head and neck, U.limb and L.limb were commonly involved. Conclusion: RTAs is a major public health problem in Assam which needs more scientific study

National noncommunicable disease monitoring survey (NNMS) in India: Estimating risk factor prevalence in adult population.

BackgroundThe primary objective of National NCD monitoring survey (NNMS) was to generate national-level estimates of key NCD indicators identified in the national NCD monitoring framework. This paper describes survey study protocol and prevalence of risk factors among adults (18-69 years).Materials and methodsNNMS was a national level cross-sectional survey conducted during 2017-18. The estimated sample size was 12,000 households from 600 primary sampling units. One adult (18-69 years) per household was selected using the World Health Organization-KISH grid. The study tools were adapted from WHO-STEPwise approach to NCD risk factor surveillance, IDSP-NCD risk factor survey and WHO-Global adult tobacco survey. Total of 8/10 indicators of adult NCD risk factors according to national NCD disease monitoring framework was studied. This survey for the first time estimated dietary intake of salt intake of population at a national level from spot urine samples.ResultsTotal of 11139 households and 10659 adults completed the survey. Prevalence of tobacco and alcohol use was 32.8% (95% CI: 30.8-35.0) and 15.9% (95% CI: 14.2-17.7) respectively. More than one-third adults were physically inactive [41.3% (95% CI: 39.4-43.3)], majority [98.4% (95% CI: 97.8-98.8)] consumed less than 5 servings of fruits and / or vegetables per day and mean salt intake was 8 g/day (95% CI: 7.8-8.2). Proportion with raised blood pressure and raised blood glucose were 28.5% (95% CI: 27.0-30.1) and 9.3% (95% CI: 8.3-10.5) respectively. 12.8% (95% CI: 11.2-14.5) of adults (40-69 years) had ten-year CVD risk of ≥30% or with existing CVD.ConclusionNNMS was the first comprehensive national survey providing relevant data to assess India's progress towards targets in National NCD monitoring framework and NCD Action Plan. Established methodology and findings from survey would contribute to plan future state-based surveys and also frame policies for prevention and control of NCDs