Rapid behavioral transitions produce chaotic mixing by a planktonic microswimmer

Despite their vast morphological diversity, many invertebrates have similar larval forms characterized by ciliary bands, innervated arrays of beating cilia that facilitate swimming and feeding. Hydrodynamics suggests that these bands should tightly constrain the behavioral strategies available to the larvae; however, their apparent ubiquity suggests that these bands also confer substantial adaptive advantages. Here, we use hydrodynamic techniques to investigate "blinking," an unusual behavioral phenomenon observed in many invertebrate larvae in which ciliary bands across the body rapidly change beating direction and produce transient rearrangement of the local flow field. Using a general theoretical model combined with quantitative experiments on starfish larvae, we find that the natural rhythm of larval blinking is hydrodynamically optimal for inducing strong mixing of the local fluid environment due to transient streamline crossing, thereby maximizing the larvae's overall feeding rate. Our results are consistent with previous hypotheses that filter feeding organisms may use chaotic mixing dynamics to overcome circulation constraints in viscous environments, and it suggests physical underpinnings for complex neurally-driven behaviors in early-divergent animals.Comment: 20 pages, 4 figure

Ciliary flocking and emergent instabilities enable collective agility in a non-neuromuscular animal

Effective organismal behavior responds appropriately to changes in the surrounding environment. Attaining this delicate balance of sensitivity and stability is a hallmark of the animal kingdom. By studying the locomotory behavior of a simple animal (\textit{Trichoplax adhaerens}) without muscles or neurons, here, we demonstrate how monociliated epithelial cells work collectively to give rise to an agile non-neuromuscular organism. Via direct visualization of large ciliary arrays, we report the discovery of sub-second ciliary reorientations under a rotational torque that is mediated by collective tissue mechanics and the adhesion of cilia to the underlying substrate. In a toy model, we show a mapping of this system onto an "active-elastic resonator". This framework explains how perturbations propagate information in this array as linear speed traveling waves in response to mechanical stimulus. Next, we explore the implications of parametric driving in this active-elastic resonator and show that such driving can excite mechanical 'spikes'. These spikes in collective mode amplitudes are consistent with a system driven by parametric amplification and a saturating nonlinearity. We conduct extensive numerical experiments to corroborate these findings within a polarized active-elastic sheet. These results indicate that periodic and stochastic forcing are valuable for increasing the sensitivity of collective ciliary flocking. We support these theoretical predictions via direct experimental observation of linear speed traveling waves which arise from the hybridization of spin and overdamped density waves. We map how these ciliary flocking dynamics result in agile motility via coupling between an amplified resonator and a tuning (Goldstone-like) mode of the system. This sets the stage for how activity and elasticity can self-organize into behavior which benefits the organism as a whole

Investigating the effect of electronic correlation on transport properties and phononic states of Vanadium

In the present work, we have tried to investigate the importance of electronic correlation on transport properties and phononic states of Vanadium (V). The temperature-dependent electrical resistivity ($\rho$) and electronic part of thermal conductivity ($\kappa_e$) due to electron-electron interactions (EEIs) and electron-phonon interactions (EPIs) are computed. The values of $\rho$ due to EEIs are found to be extremely small in comparison to $\rho$ due to EPIs. For instance, at 300 K, the calculated value of $\rho$ due to EEIs (EPIs) is $\sim$ 0.859$\times10^{-3}$ ($\sim$ 0.20) $\mu\Omega$m. The magnitudes of $\kappa_e$ due to EPIs are found to be in good agreement with the experimental results. These observations indicate the negligible importance of EEIs to these quantities for V. However, at 300 K, the value of Seebeck coefficient ($S$) at DFT+DMFT level ($\sim$ -0.547 $\mu$VK$^{-1}$) is found to be entirely different than at DFT level ($\sim 7.401$ $\mu$VK$^{-1}$). Also, the DFT+DMFT value of $S$ at 300 K is in good match with the available experimental data (-1.06 $\mu$VK$^{-1}$, 1.0 $\mu$VK$^{-1}$). Apart from this, the study of phononic states at DFT and DFT+DMFT level is performed. The obtained phononic band structure and phonon DOS at DFT+DMFT differ to a good extent from that at DFT. The maximum energy of phononic state obtained at DFT (DFT+DMFT) is $\sim$ 33.83 ($\sim$ 35.15) meV, where the result of DFT+DMFT is obtained more closer to the experimental data (35.15, 36.98 & 41.77 meV). These results highlight the importance of electronic correlation on $S$ & phononic states of simple correlated V metal

Study of serum homocysteine level in patients with chronic kidney disease and its association with renal function and serum albumin

 Background: Chronic kidney disease (CKD) includes irreversible destruction of nephrons leading to progressive decline in glomerular filtration rate. A preferential defect in Homocysteine disposal could hypothetically occur in CKD and subsequently lead to hyperhomocysteinemia. Understanding the status of Homocysteine and other parameters in CKD is useful in the management of the disease. Objective of the study is to estimate serum Homocysteine in CKD patients and its association with renal function and serum albumin in patients with CKD.Methods: The study design involves hospital based observational comparative study. The study was conducted in Department of Biochemistry in association with Department of Nephrology of Mahatma Gandhi Medical College and Hospital, Jaipur between May 2017 to June 2018. 100 diagnosed patients of CKD, visiting the Outpatient Department of Nephrology were enrolled as cases for the study. Patients having cardiovascular disease, Chronic liver disease, Age more than 60 years and pregnant females were excluded from study. The control group consists of 100 age and sex matched healthy individuals.Results: The mean serum creatinine levels of case and control group were 7.50±3.74 mg% and 0.83±0.22 mg% respectively. The mean of serum homocysteine levels of subject group was 27.35±12.52 µmol/L while the mean serum homocysteine levels of control group was 11.06±3.52 µmol/L. The serum homocysteine levels were significantly higher in the CKD patient group. The serum level of albumin in CKD patients and control group were 2.86±0.86 g/dl and 4.10±0.58 g/dl respectively. A positive correlation was found between serum creatinine and serum homocysteine levels. A negative correlation between serum homocysteine and serum albumin was found.Conclusions: Findings of the present study exhibit that serum homocysteine levels are elevated in CKD in comparison to healthy controls and it is positively correlated with serum creatinine level

Energy spectra in turbulent bubbly flows

We conduct experiments in a turbulent bubbly flow to study the nature of the transition between the classical $-$5/3 energy spectrum scaling for a single-phase turbulent flow and the $-$3 scaling for a swarm of bubbles rising in a quiescent liquid and of bubble-dominated turbulence. The bubblance parameter, which measures the ratio of the bubble-induced kinetic energy to the kinetic energy induced by the turbulent liquid fluctuations before bubble injection, is often used to characterise the bubbly flow. We vary the bubblance parameter from $b = \infty$ (pseudo-turbulence) to $b = 0$ (single-phase flow) over 2-3 orders of magnitude ($0.01 - 5$) to study its effect on the turbulent energy spectrum and liquid velocity fluctuations. The probability density functions (PDFs) of the liquid velocity fluctuations show deviations from the Gaussian profile for $b > 0$, i.e. when bubbles are present in the system. The PDFs are asymmetric with higher probability in the positive tails. The energy spectra are found to follow the $-$3 scaling at length scales smaller than the size of the bubbles for bubbly flows. This $-$3 spectrum scaling holds not only in the well-established case of pseudo-turbulence, but surprisingly in all cases where bubbles are present in the system ($b > 0$). Therefore, it is a generic feature of turbulent bubbly flows, and the bubblance parameter is probably not a suitable parameter to characterise the energy spectrum in bubbly turbulent flows. The physical reason is that the energy input by the bubbles passes over only to higher wave numbers, and the energy production due to the bubbles can be directly balanced by the viscous dissipation in the bubble wakes as suggested by Lance $\&$ Bataille (1991). In addition, we provide an alternative explanation by balancing the energy production of the bubbles with viscous dissipation in the Fourier space.Comment: J. Fluid Mech. (in press

Risperidone (depot) for schizophrenia

Background: Risperidone is the first new generation antipsychotic drug made available in a long-acting injection formulation. Objectives To examine the effects of depot risperidone for treatment of schizophrenia or related psychoses in comparison with placebo, no treatment or other antipsychotic medication. To critically appraise and summarise current evidence on the resource use, cost and cost-effectiveness of risperidone (depot) for schizophrenia. Search methods: We searched the Cochrane Schizophrenia Group's Register (December 2002, 2012, and October 28, 2015). We also checked the references of all included studies, and contacted industry and authors of included studies. Selection criteria: Randomised clinical trials comparing depot risperidone with other treatments for people with schizophrenia and/or schizophrenia-like psychoses. Data collection and analysis: Two review authors independently selected trials, assessed trial quality and extracted data. For dichotomous data, we calculated the risk ratio (RR), with 95% confidence interval (CI). For continuous data, we calculated mean differences (MD). We assessed risk of bias for included studies and created 'Summary of findings' tables using GRADE. Main results: Twelve studies, with a total of 5723 participants were randomised to the following comparison treatments: Risperidone depot versus placebo Outcomes of relapse and improvement in mental state were neither measured or reported. In terms of other primary outcomes, more people receiving placebo left the study early by 12 weeks (1 RCT, n=400, RR 0.74 95% CI 0.63 to 0.88, very low quality evidence), experienced severe adverse events in short term (1 RCT, n=400, RR 0.59 95% CI 0.38 to 0.93, very low quality evidence). There was however, no difference in levels of weight gain between groups (1 RCT, n=400, RR 2.11 95% CI 0.48 to 9.18, very low quality evidence). Risperidone depot versus general oral antipsychotics The outcome of improvement in mental state was not presented due to high levels of attrition, nor were levels of severe adverse events explicitly reported. Most primary outcomes of interest showed no difference between treatment groups. However, more people receiving depot risperidone experienced nervous system disorders (long-term:1 RCT, n=369, RR 1.34 95% CI 1.13 to 1.58, very-low quality evidence). Risperidone depot versus oral risperidone Data for relapse and severe adverse events were not reported. All outcomes of interest were rated as moderate quality evidence. Main results showed no differences between treatment groups with equivocal data for change in mental state, numbers leaving the study early, any extrapyramidal symptoms, weight increase and prolactin-related adverse events. Risperidone depot versus oral quetiapine Relapse rates and improvement in mental state were not reported. Fewer people receiving risperidone depot left the study early (long-term: 1 RCT, n=666, RR 0.84 95% CI 0.74 to 0.95, moderate quality evidence). Experience of serious adverse events was similar between groups (low quality evidence), but more people receiving depot risperidone experienced EPS (1 RCT, n=666, RR 1.83 95% CI 1.07 to 3.15, low quality evidence), had greater weight gain (1 RCT, n=666, RR 1.25 95% CI 0.25 to 2.25, low quality evidence) and more prolactin-related adverse events (1 RCT, n=666, RR 3.07 95% CI 1.13 to 8.36, very low quality evidence). Risperidone depot versus oral aripiprazole Relapse rates, mental state using PANSS, leaving the study early, serious adverse events and weight increase were similar between groups. However more people receiving depot risperidone experienced prolactin-related adverse events compared to those receiving oral aripiprazole (2 RCTs, n=729, RR 9.91 95% CI 2.78 to 35.29, very low quality of evidence). Risperidone depot versus oral olanzapine Relapse rates were not reported in any of the included studies for this comparison. Improvement in mental state using PANSS and instances of severe adverse events were similar between groups. More people receiving depot risperidone left the study early than those receiving oral olanzapine (1 RCT, n=618, RR 1.32 95% CI 1.10 to 1.58, low quality evidence) with those receiving risperidone depot also experiencing more extrapyramidal symptoms (1 RCT, n=547, RR 1.67 95% CI 1.19 to 2.36, low quality evidence). However, more people receiving oral olanzapine experienced weight increase (1 RCT, n=547, RR 0.56 95% CI 0.42 to 0.75, low quality evidence). Risperidone depot versus atypical depot antipsychotics (specifically paliperidone palmitate) Relapse rates were not reported and rates of response using PANSS, weight increase, prolactin-related adverse events and glucose-related adverse events were similar between groups. Fewer people left the study early due to lack of efficacy from the risperidone depot group (long term: 1 RCT, n=749, RR 0.60 95% CI 0.45 to 0.81, low quality evidence), but more people receiving depot risperidone required use of EPS-medication (2 RCTs, n=1666, RR 1.46 95% CI 1.18 to 1.8, moderate quality evidence). Risperidone depot versus typical depot antipsychotics Outcomes of relapse, severe adverse events or movement disorders were not reported. Outcomes relating to improvement in mental state demonstrated no difference between groups (low quality evidence). However, more people receiving depot risperidone compared to other typical depots left the study early (long-term:1 RCT, n=62, RR 3.05 95% CI 1.12 to 8.31, low quality evidence). Authors' conclusions: Depot risperidone may be more acceptable than placebo injection but it is hard to know if it is any more effective in controlling the symptoms of schizophrenia. The active drug, especially higher doses, may be associated with more movement disorders than placebo. People already stabilised on oral risperidone may continue to maintain benefit if treated with depot risperidone and avoid the need to take tablets, at least in the short term. In people who are happy to take oral medication the depot risperidone is approximately equal to oral risperidone. It is possible that the depot formulation, however, can bring a second-generation antipsychotic to people who do not reliably adhere to treatment. People with schizophrenia who have difficulty adhering to treatment, however, are unlikely to volunteer for a clinical trial. Such people may gain benefit from the depot risperidone with no increased risk of extrapyramidal side effects

Three-dimensional Lagrangian Voronoi analysis for clustering of particles and bubbles in turbulence

Three-dimensional Voronoi analysis is used to quantify the clustering of inertial particles in homogeneous isotropic turbulence using data from numerics and experiments. We study the clustering behavior at different density ratios and particle response times (i.e. Stokes numbers St). The Probability Density Functions (PDFs) of the Voronoi cell volumes of light and heavy particles show a different behavior from that of randomly distributed particles -i.e. fluid tracers-implying that clustering is present. The standard deviation of the PDF normalized by that of randomly distributed particles is used to quantify the clustering. Light particles show maximum clustering for St around 1-2. The results are consistent with previous investigations employing other approaches to quantify the clustering. We also present the joint PDFs of enstrophy and Voronoi volumes and their Lagrangian autocorrelations. The small Voronoi volumes of light particles correspond to regions of higher enstrophy than those of heavy particles, indicating that light particles cluster in higher vorticity regions. The Lagrangian temporal autocorrelation function of Voronoi volumes shows that the clustering of light particles lasts much longer than that of heavy or neutrally buoyant particles. Due to inertial effects, the Lagrangian autocorrelation time-scale of clustered light particles is even longer than that of the enstrophy of the flow itself.Comment: J. Fluid Mech. 201

The clustering morphology of freely rising deformable bubbles

We investigate the clustering morphology of a swarm of freely rising deformable bubbles. A three-dimensional Vorono\"i analysis enables us to quantitatively distinguish between two typical clustering configurations: preferential clustering and a grid-like structure. The bubble data is obtained from direct numerical simulations (DNS) using the front-tracking method. It is found that the bubble deformation, represented by the aspect ratio \chi, plays a significant role in determining which type of clustering is realized: Nearly spherical bubbles with \chi <~ 1.015 form a grid-like structure, while more deformed bubbles show preferential clustering. Remarkably, this criteria for the clustering morphology holds for different diameters of the bubbles, surface tension, and viscosity of the liquid in the studied parameter regime. The mechanism of this clustering behavior is connected to the amount of vorticity generated at the bubble surfaces.Comment: 10 pages, 5 figure

Non-bilaterians as Model Systems for Tissue Mechanics

In animals, epithelial tissues are barriers against the external environment, providing protection against biological, chemical, and physical damage. Depending on the animal's physiology and behavior, these tissues encounter different types of mechanical forces and need to provide a suitable adaptive response to ensure success. Therefore, understanding tissue mechanics in different contexts is an important research area. Here, we review recent tissue mechanics discoveries in a few early-divergent non-bilaterian animals -- Trichoplax adhaerens, Hydra vulgaris, and Aurelia aurita. We highlight each animal's simple body plan and biology, and unique, rapid tissue remodeling phenomena that play a crucial role in its physiology. We also discuss the emergent large-scale mechanics that arise from small-scale phenomena. Finally, we emphasize the enormous potential of these non-bilaterian animals to be model systems for further investigation in tissue mechanics.Comment: Review paper, Comments/suggestions are welcom

Tracking collective emotions in sixteen countries during COVID-19: A novel methodology for identifying major emotional events using Twitter

Using messages posted on Twitter, this research developed a new methodology for estimating collective emotions (CEs) within countries. It applied time-series analytic methodology to develop and demonstrate a novel application of CEs to identify emotional events that are significant at the societal level. The study analyzed over 200 million words from over 10 million Twitter messages posted in sixteen countries during the first 120 days of the COVID-19 pandemic. Daily levels of collective anxiety and positive emotions were estimated using Linguistic Inquiry and Word Count’s (LIWC) psychologically validated lexicon. The resulting time series estimates of both collective emotions were analyzed for structural breaks which mark abrupt changes in a series due to external shocks. External shocks to collective emotions come from events that are of shared emotional relevance and the analysis of structural breaks showed that a reduction in collective anxiety and increase in collective positive emotions in most countries followed WHO’s declaration of the COVID-19 situation as a global pandemic. Announcements of economic support packages and social restrictions also had similar impacts in countries. This indicated that reduction of uncertainties around the rapidly evolving COVID-19 situation during the first 120 days of the pandemic had a positive emotional impact on people in all the countries in the study. The study contributes to the field of CEs and applied research on collective psychological phenomena