Active Brownian Particles. From Individual to Collective Stochastic Dynamics

We review theoretical models of individual motility as well as collective dynamics and pattern formation of active particles. We focus on simple models of active dynamics with a particular emphasis on nonlinear and stochastic dynamics of such self-propelled entities in the framework of statistical mechanics. Examples of such active units in complex physico-chemical and biological systems are chemically powered nano-rods, localized patterns in reaction-diffusion system, motile cells or macroscopic animals. Based on the description of individual motion of point-like active particles by stochastic differential equations, we discuss different velocity-dependent friction functions, the impact of various types of fluctuations and calculate characteristic observables such as stationary velocity distributions or diffusion coefficients. Finally, we consider not only the free and confined individual active dynamics but also different types of interaction between active particles. The resulting collective dynamical behavior of large assemblies and aggregates of active units is discussed and an overview over some recent results on spatiotemporal pattern formation in such systems is given.Comment: 161 pages, Review, Eur Phys J Special-Topics, accepte

Burden and risk factors for Pseudomonas aeruginosa community-acquired pneumonia:a Multinational Point Prevalence Study of Hospitalised Patients

Pseudornonas aeruginosa is a challenging bacterium to treat due to its intrinsic resistance to the antibiotics used most frequently in patients with community-acquired pneumonia (CAP). Data about the global burden and risk factors associated with P. aeruginosa-CAP are limited. We assessed the multinational burden and specific risk factors associated with P. aeruginosa-CAP. We enrolled 3193 patients in 54 countries with confirmed diagnosis of CAP who underwent microbiological testing at admission. Prevalence was calculated according to the identification of P. aeruginosa. Logistic regression analysis was used to identify risk factors for antibiotic-susceptible and antibiotic-resistant P. aeruginosa-CAP. The prevalence of P. aeruginosa and antibiotic-resistant P. aeruginosa-CAP was 4.2% and 2.0%, respectively. The rate of P. aeruginosa CAP in patients with prior infection/colonisation due to P. aeruginosa and at least one of the three independently associated chronic lung diseases (i.e. tracheostomy, bronchiectasis and/or very severe chronic obstructive pulmonary disease) was 67%. In contrast, the rate of P. aeruginosa-CAP was 2% in patients without prior P. aeruginosa infection/colonisation and none of the selected chronic lung diseases. The multinational prevalence of P. aeruginosa-CAP is low. The risk factors identified in this study may guide healthcare professionals in deciding empirical antibiotic coverage for CAP patients

Agriculture Insurance’s Outreach Constrained by Procedural Delays and Norms: Reflections from North Karnataka, India

Karnataka is one of the states, which experienced severe drought continuously for four years since 2014. In addition, heavy rainfall for the past two years has adversely affected agriculture produce in the entire state putting farmers into debt trap as most of them are not covered by crop insurance for crop failure. Although crop insurance was available to farmers in India since 1972, the coverage across the states including Karnataka was not found to be satisfactory. The average percentage of farmers covered under crop insurance was less than 10% during 1999-2015,both for India and Karnataka. It was 11.3% under NAIS 2015 kharif,increased to 12.2% in 2016, 17.1% in 2017 going down to 15.6% in 2018 and to 14.1% in 2019 under Pradhan Mantri Fasal Bima Yojana (PMFBY)kharif in Karnataka. PMFBY was one new kind of agriculture insurance company and introduced throughout the country in 2016.This paper examines the performance of this scheme with specific reference to north Karnataka based on primary data collected from farmers’ survey in four districts, secondary data collected from official documents and first-hand information gathered from regional stakeholder workshops organized in six selected districts of north Karnataka. The study tries to look into the extent of coverage and, flaws and merits of crop insurance schemes with reference to problems faced by farmers in getting insurance coverage and claims. The study covered around 1000 stakeholders including farmers,officials of banks, department of economics and statistics, agriculture department and insurance agencies, representatives of gram panchayats and cooperative societies. Three agricultural crop seasons have passed since then. Central government has brought in some changes in guidelines and is likely to make further changes in procedures in response to concerns expressed by States and farmers’ representatives. Follow up discussions with key stakeholders in Karnataka held after the initial farmers’ survey reveal that while a few of the anomalies in applying for crop insurance have been addressed by the concerned departments, major obstacles in assessment and claims continue to exasperate farmers who are miffed by these procedural lapses. This paper throws light on some of these issues and discusses measures to make crop insurance, particularly PMFBY farmers’ friendly

Ion implanted and laser processed solar cells made from EFG ribbon

The use of ion implantation and laser processing has a number of conceptual advantages which could result in a low-cost process for manufacturing high performance solar cells from EFG ribbon. Samples were phosphorus ion implanted, laser processed using either a pulse large area ruby laser or a scanned YAG laser with a second harmonic generator, and then processed into solar cells. Many of the samples had high reverse leakage and it was determined that this was due to too high a laser processing power. This effect was determined to be more severe for the scanned YAG laser, and is thought to be due to point defects. Cells were made from EFG ribbon with a low laser energy density which had efficiencies of up to 10% at AMI demonstrating the feasibility of this approach. High efficiencies should be attainable by optimizing the laser processing parameters

One size does not fit all: Monitoring faecal glucocorticoid metabolites in marsupials

Marsupial research, conservation, and management can benefit greatly from knowledge about glucocorticoid (GC) secretion patterns because GCs influence numerous aspects of physiology and play a crucial role in regulating an animal's response to stressors. Faecal glucocorticoid metabolites (FGM) offer a noninvasive tool for tracking changes in GCs over time. To date, there are relatively few validated assays for marsupials compared with other taxa, and those that have been published generally test only one assay. However, different assays can yield very different signals of adrenal activity. The goal of this study was to compare the performance of five different enzyme immunoassays (EIAs) for monitoring adrenocortical activity via FGM in 13 marsupial species. We monitored FGM response to two types of events: biological stressors (e.g., transport, novel environment) and pharmacological stimulation (ACTH injection). For each individual animal and assay, FGM peaks were identified using the iterative baseline approach. Performance of the EIAs for each species was evaluated by determining (1) the percent of individuals with a detectable peak 0.125-4.5 days post-event, and (2) the biological sensitivity of the assay as measured by strength of the post-event response relative to baseline variability (Z-score). Assays were defined as successful if they detected a peak in at least 50% of the individuals and the mean species response had a ZP2. By this criterion, at least one assay was successful in 10 of the 13 species, but the best performing assay varied amo g species, even those species that were closely related. Furthermore, the ability to confidently assess assay performance was influenced by the experimental protocols used. We discuss the implications of our findings for biological validation studies