Parallel-cascade realizations and approximations of truncated volterra systems

Journal ArticleThis paper introduces parallel-cascade realizations of truncated Volterra systems with arbitrary, but finite order of nonlinearity. Parallel-cascade realizations implement higher-order Volterra systems using parallel and multiplicative combinations of lower-order Volterra systems. Such realizations are very modular and therefore well-suited for VLSI implementation. A systematic way of approximating higher-order Volterra systems in parallel-cascade form using a reduced number of branches and a bound on the mean-square error in the output signals caused by such approximate realizations are derived in this paper. A variation of the parallel-cascade structure in which a pth order Volterra filter is implemented as a parallel combination of linear filters whose outputs are raised to the pth power is also described in this paper

Adaptive parallel-cascade truncated volterra filters

Journal ArticleAbstract-This paper studies adaptive truncated Volterra filters employing parallel-cascade structures. Parallel-cascade realizations implement higher order Volterra systems a s a parallel connection of multiplicative combinations of lower order truncated Volterra systems. A normalized LMS adaptive filter is developed, and its performance capabilities are evaluated using a series of simulation experiments. The experimental results indicate that the normalized LMS adaptive parallel-cascade Volterra filter has superior convergence properties over several competing structures. This paper also includes an experiment that demonstrates the capability of the parallel-cascade adaptive system to reduce its implementation complexity by using fewer than the maximum number of branches required for the most general realization of the system

On The Application Of Log Compression and Enhanced Denoising In Contrast Enhancement Of Digital Radiography Images

Digital radiography (DR) is becoming popular for the point of care imaging in the recent past. To reduce the radiation exposure, controlled radiation based on as low as reasonably achievable (ALARA) principle is employed and this results in low contrast images. To address this issue, post-processing algorithms such as the Multiscale Image Contrast Amplification (MUSICA) algorithm can be used to enhance the contrast of DR images even with a low radiation dose. In this study, a modification of the MUSICA algorithm is investigated to determine the potential for further contrast improvement specifically for DR images. The conclusion is that combining log compression and its inverse at the appropriate stage with a multi-stage MUSICA and denoising is very promising. The proposed method resulted in an average of 66.5 % increase in the mean contrast-to-noise ratio (CNR) for the test images considered.Comment: 4 pages, 4 figure

Fowler's syndrome: a primary disorder of urethral sphincter relaxation

Key content: Urinary retention is a relatively uncommon presentation in young women. Women with Fowler's syndrome are often found to have an abnormally elevated urethral pressure profile, increased urethral sphincter volume and characteristically abnormal electromyography of the urethral sphincter. The only treatment that has been found to restore voiding in women with Fowler's syndrome is sacral neuromodulation. Sphincter injections of botulinum toxin are a possible outpatient‐based alternative. / Learning objectives: To review the typical symptoms and signs associated with Fowler's syndrome. To share the current understanding about why this condition may occur. To understand how to evaluate and treat a woman with suspected Fowler's syndrome. / Ethical issues: Fowler's syndrome should be considered in women presenting with urinary retention where the cause for retention is uncertain

Parallel-cascade realizations and approximations of truncated volterra systems

Journal ArticleAbstract This paper introduces parallel-cascade realizations of truncated Volterra systems with arbitrary, but finite order of nonlinearity. Parallel-cascade realizations implement higher-order Volterra systems using parallel and multiplicative combinations of lower-order Volterra systems. Such realizations are very modular and therefore well-suited for VLSI implementation. A Systematic way of approximating higher-order Volterra systems in parallel-cascade form using a reduced number of branches and a bound on the mean-square error in the output signals caused by such approximate realizations are derived in this paper. A variation of the parallel-cascade structure in which a pth order Volterra filter is implemented as a parallel combination of linear filters whose outputs are raised to the pth power is also described in this paper

Fine-scale spatial and temporal acoustic occurrence of island-associated odontocetes near a mid-oceanic atoll in the northern Indian Ocean

© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Panicker, D., Baumgartner, M. F., & Stafford, K. M. Fine-scale spatial and temporal acoustic occurrence of island-associated odontocetes near a mid-oceanic atoll in the northern Indian Ocean. Marine Ecology Progress Series, 683, (2022): 195–208, https://doi.org/10.3354/meps13947.Temporal patterns of oceanic predators can provide valuable information on both lunar and diel influences not just on the distributions of these predators, but also on prey patches that are often difficult to study. Mid-oceanic island chains in the northern Indian Ocean have high odontocete occurrence, but the ecology of these animals is not well characterized. We investigated fine-scale spatial and temporal patterns of island-associated odontocetes using passive acoustic monitoring from January 2019 to January 2020 around Kavaratti Island, Lakshadweep, India. Based on opportunistic recordings in the presence of odontocetes, the majority of the detected whistles were likely made by spinner dolphins Stenella longirostris. We identified a resident population whose whistle occurrence was significantly influenced by month, site, and diel and lunar cycles. More acoustic detections were made in the northeast monsoon month of November and fewer during pre-monsoon and southwest monsoon periods. Distinct day-night differences along with fine-scale temporal variability were also observed, suggesting that delphinids use nearshore waters as a daytime resting habitat. Odontocete detections were highest during the new moon period and lowest during the first quarter phase. Detection rates were higher on the south side of the island. Our study shows that solar and lunar cycles modulate odontocete vocal occurrence, presumably through influences on their prey. Similarities of odontocete occurrence around Lakshadweep to other mid-oceanic island chains suggests that an island-associated micronekton community may exist around Lakshadweep that may also be important to other pelagic species targeted by local fisheries.Funding was provided by the Office of Naval Research Marine Mammal Biology Program, USA, under grant N000141812795. We thank Ajith Kumar, the National Centre for Biological Sciences and Idrees Babu for in-country support

ANTIBACTERIAL ACTIVITY OF TABERNAEMONTANA DIVARICATA (APOCYNACEAE) SECONDARY METABOLITES CAPPED SILVER AND GOLD NANOPARTICLES

Objective: To study the antibacterial activity of Tabernaemontana divaricata (Apocynaceae) secondary metabolites capped silver nanoparticles(SNPs) and gold nanoparticles (AuNPs).Methods: In the present investigation, SNPs and AuNPs were synthesized using an aqueous extract of T. divaricata leaves. Leaf aqueous extractwas mixed with 1 mM silver nitrate and chloroauric acid for the biosynthesis of nanoparticles, and the same was analyzed using ultraviolet-visible(UV-Vis) spectrophotometer and particle size analyzer. The antibacterial activity of SNPs and AuNPs was determined against various bacterial culturesincluding laboratory isolates using the agar well diffusion method.Results: The results recorded from UV-Vis spectrum supported the biosynthesis and characterization of SNPs and AuNPs. The SNPs when comparedto AuNPs, showed the highest antibacterial activity against Gram-positive and Gram-negative bacteria.Conclusion: The present study envisions on the biosynthesis of SNPs from T. divaricata plant which are emerging as antibacterial therapy in modernmedical applications.Keywords: Antibacterial activity, Gold nanoparticles, Silver nanoparticles, Tabernaemontana divaricata

Genotoxic effects of culture media on human pluripotent stem cells

Culture conditions play an important role in regulating the genomic integrity of Human Pluripotent Stem Cells (HPSCs). We report that HPSCs cultured in Essential 8 (E8) and mTeSR, two widely used media for feeder-free culturing of HPSCs, had many fold higher levels of ROS and higher mitochondrial potential than cells cultured in Knockout Serum Replacement containing media (KSR). HPSCs also exhibited increased levels of 8-hydroxyguanosine, phospho-histone-H2a.X and p53, as well as increased sensitivity to γ-irradiation in these two media. HPSCs in E8 and mTeSR had increased incidence of changes in their DNA sequence, indicating genotoxic stress, in addition to changes in nucleolar morphology and number. Addition of antioxidants to E8 and mTeSR provided only partial rescue. Our results suggest that it is essential to determine cellular ROS levels in addition to currently used criteria i.e. pluripotency markers, differentiation into all three germ layers and normal karyotype through multiple passages, in designing culture media

A practical approach to assessing and managing sexual dysfunction in multiple sclerosis

Sexual dysfunction is common in both men and women with multiple sclerosis but is often under-reported and undertreated. Neurologists report that a major barrier to discussing sexual dysfunction with patients is their lack of knowledge. Here we review the common presentations of sexual dysfunction, discuss its causes in people with multiple sclerosis, and provide a practical approach for neurologists to assess and manage these problems

A Method to Identify and Isolate Pluripotent Human Stem Cells and Mouse Epiblast Stem Cells Using Lipid Body-Associated Retinyl Ester Fluorescence.

We describe the use of a characteristic blue fluorescence to identify and isolate pluripotent human embryonic stem cells and human-induced pluripotent stem cells. The blue fluorescence emission (450–500 nm) is readily observed by fluorescence microscopy and correlates with the expression of pluripotency markers (OCT4, SOX2, and NANOG). It allows easy identification and isolation of undifferentiated human pluripotent stem cells, high-throughput fluorescence sorting and subsequent propagation. The fluorescence appears early during somatic reprogramming. We show that the blue fluorescence arises from the sequestration of retinyl esters in cytoplasmic lipid bodies. The retinoid-sequestering lipid bodies are specific to human and mouse pluripotent stem cells of the primed or epiblast-like state and absent in naive mouse embryonic stem cells. Retinol, present in widely used stem cell culture media, is sequestered as retinyl ester specifically by primed pluripotent cells and also can induce the formation of these lipid bodies