Comprehending deterministic and stochastic occasional uncoupling induced synchronizations through each other

In this paper, we numerically study the stochastic and the deterministic occasional uncoupling methods of effecting identical synchronized states in low dimensional, dissipative, diffusively coupled, chaotic flows that are otherwise not synchronized when continuously coupled at the same coupling strength parameter. In the process of our attempt to understand the mechanisms behind the success of the occasional uncoupling schemes, we devise a hybrid between the transient uncoupling and the stochastic on-off coupling, and aptly name it the transient stochastic uncoupling---yet another stochastic occasional uncoupling method. Our subsequent investigation on the transient stochastic uncoupling allows us to surpass the effectiveness of the stochastic on-off coupling with very fast on-off switching rate. Additionally, through the transient stochastic uncoupling, we establish that the indicators quantifying the local contracting dynamics in the corresponding transverse manifold are generally not useful in finding the optimal coupling region of the phase space in the case of the deterministic transient uncoupling. In fact, we highlight that the autocorrelation function---a non-local indicator of the dynamics---of the corresponding response system's chaotic time-series dictates when the deterministic uncoupling could be successful. We illustrate all our heuristic results using a few well-known examples of diffusively coupled chaotic oscillators.Comment: Accepted in Eur. Phys. J.

TransDocAnalyser: A Framework for Offline Semi-structured Handwritten Document Analysis in the Legal Domain

State-of-the-art offline Optical Character Recognition (OCR) frameworks perform poorly on semi-structured handwritten domain-specific documents due to their inability to localize and label form fields with domain-specific semantics. Existing techniques for semi-structured document analysis have primarily used datasets comprising invoices, purchase orders, receipts, and identity-card documents for benchmarking. In this work, we build the first semi-structured document analysis dataset in the legal domain by collecting a large number of First Information Report (FIR) documents from several police stations in India. This dataset, which we call the FIR dataset, is more challenging than most existing document analysis datasets, since it combines a wide variety of handwritten text with printed text. We also propose an end-to-end framework for offline processing of handwritten semi-structured documents, and benchmark it on our novel FIR dataset. Our framework used Encoder-Decoder architecture for localizing and labelling the form fields and for recognizing the handwritten content. The encoder consists of Faster-RCNN and Vision Transformers. Further the Transformer-based decoder architecture is trained with a domain-specific tokenizer. We also propose a post-correction method to handle recognition errors pertaining to the domain-specific terms. Our proposed framework achieves state-of-the-art results on the FIR dataset outperforming several existing modelsComment: This paper has been accepted in 17th International Conference on Document Analysis and Recognition(ICDAR) as an Oral presentatio

Intra-night Optical Variability of BL Lacs, Radio-Quiet Quasars and Radio-Loud Quasars

We report optical monitoring observations of 20 high-luminosity AGN, 12 of which are radio-quiet quasars (RQQs). Intra-night optical variability (INOV) was detected for 13 of the 20 objects, including 5 RQQs. The variations are distinctly stronger and more frequent for blazars than for the other AGN classes. By combining these data with results obtained earlier in our program, we have formed an enlarged sample consisting of 9 BL Lacs, 19 RQQs and 11 lobe-dominated radio-loud quasars. The moderate level of rapid optical variability found for both RQQs and radio lobe-dominated quasars argues against a direct link between INOV and radio-loudness. We supplemented the present observations of 3 BL Lacs with additional data from the literature. In this extended sample of 12 well observed BL Lacs, stronger INOV is found for the EGRET detected BL Lacs.Comment: 8 pages, 3 Postscript figures, Accepted for publication in MNRAS, uses mn2e.cl

A Digital Image Processing Tool for size and number density distribution of precipitates in creep exposed material

Present paper deals with developing an advanced digital image processing tool for determination of size and number density of precipitates present in creep exposed P92 steel. The image processing tool box in MATLAB is usually employed for noise detection and removal, edge detection, cropping, histogram of region of interest as well as size wise distribution of the desired objects from the micrograph. This tool helps in fast and accurate acquisition of information. In this investigation, creep testing has been carried out on two P92 steel specimens at temperature of 650C and stress of 120MPa till rupture. Scanning electron microscopy was used to capture images of the specimen in as-tempered condition and in the near rupture gage region after creep rupture. The developed software has been used to analyze the micrographs for quantification of precipitates in terms of area fraction, size and number density. The use of edge detection technique in the developed software helps in avoiding human intervention during image thresholding thereby increasing accuracy in precipitate sizing. Findings from this investigation have been used to evaluate the role of precipitation morphology for specimen failure due to creep especially in precipitate strengthened steel like P92 steel

Star formation in young star cluster NGC 1893

We present a comprehensive multi-wavelength study of the star-forming region NGC 1893 to explore the effects of massive stars on low-mass star formation. Using near-infrared colours, slitless spectroscopy and narrow-band $H\alpha$ photometry in the cluster region we have identified candidate young stellar objects (YSOs) distributed in a pattern from the cluster to one of the nearby nebulae Sim 129. The $V, (V-I)$ colour-magnitude diagram of the YSOs indicates that majority of these objects have ages between 1 to 5 Myr. The spread in the ages of the YSOs may indicate a non-coeval star formation in the cluster. The slope of the KLF for the cluster is estimated to be $0.34\pm0.07$, which agrees well with the average value ($\sim 0.4$) reported for young clusters. For the entire observed mass range $0.6 < M/M_\odot \le 17.7$ the value of the slope of the initial mass function, $`\Gamma$', comes out to be $-1.27\pm0.08$, which is in agreement with the Salpeter value of -1.35 in the solar neighborhood. However, the value of $`\Gamma$' for PMS phase stars (mass range $0.6 < M/M_\odot \le 2.0$) is found to be $-0.88\pm0.09$ which is shallower than the value ($-1.71\pm0.20$) obtained for MS stars having mass range $2.5 < M/M_\odot \le 17.7$ indicating a break in the slope of the mass function at $\sim 2 M_\odot$. Estimated $`\Gamma$' values indicate an effect of mass segregation for main-sequence stars, in the sense that massive stars are preferentially located towards the cluster center. The estimated dynamical evolution time is found to be greater than the age of the cluster, therefore the observed mass segregation in the cluster may be the imprint of the star formation process. There is evidence for triggered star formation in the region, which seems to govern initial morphology of the cluster.Comment: Accepted for the publication in MNRAS, 21 pages, 26 figures, 10 table

Studies on Genotoxic Effects of Mobile Phone Radiation on A375 Cells

Introduction: Radiation from cell phones has been associated with an increased risk of cancer. The literature has reported evidence of certain biological effects resulting from exposure to various wavelengths, doses, and intensities of radiofrequency radiation. The present study aimed to evaluate the possible adverse effects of radiation from a GSM mobile phone operating at 900 MHz on human melanoma A375 cells. Material and Methods: Cellular morphology was observed under an inverted phase contrast microscope. Cell viability was determined through trypan blue dye exclusion and clonogenic assay. Moreover, flow cytometry was applied to detect DNA damage, cell cycle arrest, and reactive oxygen species (ROS) production. Cellular reduced glutathione (GSH) content was estimated by measuring the total soluble thiol. In addition, the physico-chemical changes were assessed using spectrophotometer and viscometer. Results: This study revealed that there was no change in cellular morphology and necrotic cell killing; although a small effect was observed on delayed cell death. Depletion in GSH content was noted, but ROS generation was not significantly different from that of the control group. No DNA damage was found during such exposure and there was no alteration in cell cycle distribution. In vitro evaluation of radiation effect on calf thymus DNA showed a slight perturbation in absorption spectra that was completely reversible with time. On the other hand, viscometric analysis showed no changes. Conclusion: From the findings, it can be concluded that this range of mobile phone radiation for 60 min of continuous exposure has no genotoxic impact on A375 cells

CCD photometry in VRI bands of the galactic cluster NGC 2818

The open cluster NGC 2818 containing a planetary nebula has been observed in VRI bands using the CCD system at prime focus of the 2.3- metre Vainu Bappu Telescope. The study extending to stars V ~ 21 magnitude establishes the distance modulus as (m-M)0 = 12.9 &#177;0.1 for the cluster. Based on the fitting of theoretical isochrones computed for solar metallicity, an age of 5(&#177;1) &#215; 108 years has been assigned to the cluster. Association of the planetary nebula with the cluster indicates that the progenitor mass of the planetary nebula on the main sequence is &#8805;2.5M&#x02299;