Statistics of synchronization times in Kuramoto oscillators

The synchronization of coupled systems is a widely studied phenomenon in nonlinear science. As a completely synchronized state emerges asymptotically, it is pertinent to quantify the statistics of the timescales in which it is attained. We study the Kuramoto model, a paradigmatic model of synchronization, and record the time at which the synchronized state is reached for the first time. The First Synchronization Time (FST), on suitable rescaling, exhibits a universal distribution for a wide range of parameter values and even in the presence of noise. We obtain an approximate time evolution of the order parameter using the celebrated Ott-Antonsen ansatz and analytically demonstrate that the FST exhibits a universal Gumbel distribution

Field Enhancement in Nanoparticles Due to IR Vortex Beams

In this report we present our study of interaction of light carrying OAM (Orbital Angular Momentum) with nanometric metallic discs. Plasmonic effects are known to give rise to high local field enhancement factors in gold nano-discs [1]. These high intensities near fields have found use in a wide variety of imaging and detection applications [2]. The local field enhancement factor near the surface of the disc was calculated numerically using finite element method using the Comsol package. We report a significant increase in the local field enhancement factor for light beams carrying OAM compared to Gaussian beams which are attributed to localised surface plasmon resonances (LSPR). Such large enhancements in the field can be immensely useful in the field on near field microscopy and electron generation. © The Electrochemical Societ

Interaction of Tungsten tips with Laguerre-Gaussian beams

Interaction of femtosecond laser pulses with metallic tips have been studied extensively and they have proved to be a very good source of ultrashort electron pulses. We present our study of interaction of Laguerre-Gaussian (LG) laser modes with Tungsten tips. We report a change in the order of the interaction for LG beams and the difference in the order of interaction is attributed to ponderomotive shifts in the energy levels corresponding to the enhanced near field intensity supported by numerical simulations

Above-threshold ionization of argon with ultrashort orbital-angular-momentum beams

Light-matter interaction with laser pulses endowed with orbital angular momentum (OAM) raises a fundamental question about the nature of the transfer of this property of light to matter. In this work, a "reaction microscope" is used for precise measurement of the momentum of ionized photoions and photoelectrons from the interaction of Ar atoms with a linearly polarized, ultrashort (similar to 25 fs), moderately intense (10(13)-10(14) W/cm(2)) OAM carrying laser pulses. The angle and energy-resolved photoelectron spectrum is compared with the photoelectron spectrum obtained from the interaction with the laser beams with no OAM at similar intensities. No evidence of angular momentum transfer to the electrons from light is observed in our experiment

Measurement of normal reference values of spinal canal diameter andal reference values of spinal canal diameter and space available for cord (SAC) at mid sagittal level in cervical spine (C3 to C7) in adult East Indian population by MRI

Background: Assessment of cervical spinal stenosis, which is not very uncommon presentation among adult age group, is necessary for planning of the management protocol, especially regarding surgical intervention, if necessary. Specific measurements used for assessing spinal canal stenosis, the spinal canal diameter and space available for cord (SAC) at mid sagittal level are considered  to be very important ones. Materials & Methods: To determine the normal range of the absolute values of these two parameters in the local population and their importance in predicting cervical canal stenosis, we selected 100 asymptomatic adult subjects of each of both sexes and 50 symptomatic subjects of each of both sexes. The parameters used in this study for assessment of cervical spinal canal stenosis were mid sagittal spinal canal diameter and the space available for the cord (SAC), which was measured using T2 weighted axial and sagittal MRI cuts at the respective vertebral level.Results: In our study, we analyzed 100 asymptomatic subjects by MRI study (T2 weighted sagittal and axial images) for determination of normal  reference values of canal diameter and space available for cord in C3 to C7 vertebral body level. The values of canal diameter (mean +/- 2SD) in different levels were 12.0±3.3mm (C3); 12.0±2.32mm (C4); 12.0±2.32mm (C5); 12.0±2.3mm (C6); 12.6±2.62mm (C7) and the corresponding space available for cord values were 5.0±2.76mm (C3); 5.1±1.92mm (C4); 5.3±2.14mm (C5); 5.6±2.08mm (C6); 6.3±2.54mm (C7) levels.Conclusion: It is well recognized that mid sagittal spinal canal diameter and space available for the cord (SAC) in cervical vertebrae (C3 to C7) varies considerably in normal adult population of both the sexes and decrease in them will result in cervical stenosis symptoms. Knowledge of normal reference values of these two parameters in Indian population will be helpful for concerned researchers and the normal acceptable range of values will be very helpful for the clinicians to predict spinal canal stenosis and to decide for the necessity of surgical intervention

Lewy Body-like Pathology and Loss of Dopaminergic Neurons in Midbrain Organoids Derived from Familial Parkinson’s Disease Patient

Progressive accumulation of α-Synuclein (αSyn) in Lewy bodies (LBs) and loss of dopaminergic (DA) neurons are the hallmark pathological features of Parkinson’s disease (PD). Although currently available in vitro and in vivo models have provided crucial information about PD pathogenesis, the mechanistic link between the progressive accumulation of αSyn into LBs and the loss of DA neurons is still unclear. To address this, it is critical to model LB formation and DA neuron loss, the two key neuropathological aspects of PD, in a relevant in vitro system. In this study, we developed a human midbrain-like organoid (hMBO) model of PD. We demonstrated that hMBOs generated from induced pluripotent stem cells (hiPSCs), derived from a familial PD (fPD) patient carrying αSyn gene (SNCA) triplication accumulate pathological αSyn over time. These cytoplasmic inclusions spatially and morphologically resembled diverse stages of LB formation and were composed of key markers of LBs. Importantly, the progressive accumulation of pathological αSyn was paralleled by the loss of DA neurons and elevated apoptosis. The model developed in this study will complement the existing in vitro models of PD and will provide a unique platform to study the spatiotemporal events governing LB formation and their relation with neurodegeneration. Furthermore, this model will also be beneficial for in vitro screening and the development of therapeutic compounds

SAtellite-based Marine Process Understanding, Development, Research and Applications for Blue Economy (SAMUDRA): A Technology Demonstration Program in the Bay of Bengal

SAtellite-based Marine Process Understanding, Development, Research and Applications (SAMUDRA) for blue economy, a technology development program of the Space Applications Centre, is an umbrella program covering research and applications geared toward physical and biological oceanography making use of current and future satellite observations for developing the nation’s blue economy. The main motivation behind this project was to develop satellite and numerical model-based information and value-added products and to demonstrate the implementation of developed applications for operational requirements. The program also aimed at improving existing methodologies for various applications by utilizing space-based inputs. Several field campaigns with the use of NavIC-enabled instruments and NABHMITRA were conducted for measuring biophysical parameters and validation of developed applications in the coastal regions. One of the key aspects of this project was development of web-based customized tools/dissemination system for providing the information to the end users. Some of the key/notable achievements of SAMUDRA were development of a portal OceanEye (tailor-made web-portal for Shipping Corporation of India), storm-surge/inundation system, oil-spill trajectory modeling, level-next potential fishing zone algorithm and rip current alert system