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For microscale gaps, DC breakdown voltage is described theoretically and through simulation by accounting for field emission generated electrons and the subsequent ionization of neutral gas and ion-induced secondary electron emission. Here, we extend DC microscale breakdown theory to AC. Particle-in-cell (PIC) simulations show that breakdown voltage V varies linearly with gap distance d independent of frequency and the ion-induced secondary electron coefficient γ S E for d ≲ 4 μ m , where field emission dominates breakdown over ionization and avalanche. For d ≳ 4 μ m and γ S E = 0 , DC breakdown voltage increases linearly with d; for γ S E = 0.05 , DC breakdown voltage decreases to a minimum before beginning to increase at larger gap distances. For AC fields with γ S E = 0.05 , V behaves similarly to the DC case with the decrease corresponding to secondary emission occurring at higher voltages and larger gap distances with increasing frequency. At 10 GHz and γ S E = 0.05 , V resembles that of the DC case with γ S E = 0 up to ∼8 μm, suggesting that increasing the frequency effectively changes the number of ions striking the electrodes and the resulting electrons released. Phase space plots showing electron and ion velocities as a function of position across the gap show that electrons and ions are increasingly trapped within the gap with increasing frequency, reducing the number of ions that can strike the cathode and the subsequent secondary emission. Incorporating the resulting effective secondary emission coefficient for AC microscale gaps yields a simple phenomenologically based modification of the DC microscale gas breakdown equation. [ABSTRACT FROM AUTHOR]

Widespread loss of genes on the Y is considered a hallmark of sex chromosome differentiation. Here we show that the initial stages of Y evolution are driven by massive amplification of distinct classes of genes. The neo-Y chromosome of Drosophila miranda initially contained about 3,000 protein-coding genes, but has gained over 3,200 genes since its formation about 1.5 million years ago primarily by tandem amplification of protein-coding genes ancestrally present on this chromosome. We show that distinct evolutionary processes may account for this drastic increase in gene number on the Y. Testis-specific and dosage-sensitive genes appear to have amplified on the Y to increase male fitness. A distinct class of meiosis-related multi-copy Y genes independently co-amplified on the X, and their expansion is probably driven by conflicts over segregation. Co-amplified X/Y genes are highly expressed in testis, enriched for meiosis and RNA interference functions and are frequently targeted by small RNAs in testis. This suggests that their amplification is driven by X versus Y antagonism for increased transmission, where sex chromosome drive suppression is probably mediated by sequence homology between the suppressor and distorter through the RNA interference mechanism. Thus, our analysis suggests that newly emerged sex chromosomes are a battleground for sexual and meiotic conflict.

Sex-chromosomes have formed repeatedly across Diptera from ordinary autosomes, and X-chromosomes mostly conserve their ancestral genes. Y-chromosomes are characterized by abundant gene-loss and an accumulation of repetitive DNA, yet the nature of the gene repertoire of fly Y-chromosomes is largely unknown. Here we trace gene-content evolution of Y-chromosomes across 22 Diptera species, using a subtraction pipeline that infers Y genes from male and female genome, and transcriptome data. Few genes remain on old Y-chromosomes, but the number of inferred Y-genes varies substantially between species. Young Y-chromosomes still show clear evidence of their autosomal origins, but most genes on old Y-chromosomes are not simply remnants of genes originally present on the proto-sex-chromosome that escaped degeneration, but instead were recruited secondarily from autosomes. Despite almost no overlap in Y-linked gene content in different species with independently formed sex-chromosomes, we find that Y-linked genes have evolved convergent gene functions associated with testis expression. Thus, male-specific selection appears as a dominant force shaping gene-content evolution of Y-chromosomes across fly species.

Alternative pre-mRNA splicing ("AS") greatly expands proteome diversity, but little is known about the evolutionary landscape of AS in Drosophila and how it differs between embryonic and adult stages or males and females. Here we study the transcriptomes from several tissues and developmental stages in males and females from four species across the Drosophila genus. We find that 20-37% of multi-exon genes are alternatively spliced. While males generally express a larger number of genes, AS is more prevalent in females, suggesting that the sexes adopt different expression strategies for their specialized function. While the number of total genes expressed increases during early embryonic development, the proportion of expressed genes that are alternatively spliced is highest in the very early embryo, before the onset of zygotic transcription. This indicates that females deposit a diversity of isoforms into the egg, consistent with abundant AS found in ovary. Cluster analysis by gene expression ("GE") levels shows mostly stage-specific clustering in embryonic samples, and tissue-specific clustering in adult tissues. Clustering embryonic stages and adult tissues based on AS profiles results in stronger species-specific clustering, suggesting that diversification of splicing contributes to lineage-specific evolution in Drosophila. Most sex-biased AS found in flies is due to AS in gonads, with little sex-specific splicing in somatic tissues.

Sex chromosomes have evolved independently in many different taxa, and so have mechanisms to compensate for expression differences on sex chromosomes in males and females. Different clades have evolved vastly different ways to achieve dosage compensation, including hypertranscription of the single X in male Drosophila, downregulation of both X's in XX Caenorhabditis, or inactivation of one X in female mammals. In the flour beetle Tribolium, the X appears hyperexpressed in both sexes, which might represent the first of two steps to evolve dosage compensation along the paths mammals may have taken (i.e., upregulation of X in both sexes, followed by inactivation of one X in females). Here we test for dosage compensation in Strepsiptera, a sister taxon to beetles. We identify sex-linked chromosomes in Xenos vesparum based on genomic analysis of males and females, and show that its sex chromosome consists of two chromosomal arms in Tribolium: The X chromosome that is shared between Tribolium and Strepsiptera, and another chromosome that is autosomal in Tribolium and another distantly related Strepsiptera species, but sex-linked in X. vesparum. We use RNA-seq (RNA sequencing) to show that dosage compensation along the X of X. vesparum is partial and heterogeneous. In particular, genes that are X-linked in both beetles and Strepsiptera appear fully dosage compensated probably through downregulation in both sexes, whereas genes on the more recently added X segment have evolved only partial dosage compensation. In addition, reanalysis of published RNA-seq data suggests that Tribolium has evolved dosage compensation, without hypertranscribing the X in females. Our results demonstrate that patterns of dosage compensation are highly variable across sex-determination systems and even within species.

Snakes exhibit genetic sex determination, with female heterogametic sex chromosomes (ZZ males, ZW females). Extensive cytogenetic work has suggested that the level of sex chromosome heteromorphism varies among species, with Boidae having entirely homomorphic sex chromosomes, Viperidae having completely heteromorphic sex chromosomes, and Colubridae showing partial differentiation. Here, we take a genomic approach to compare sex chromosome differentiation in these three snake families. We identify homomorphic sex chromosomes in boas (Boidae), but completely heteromorphic sex chromosomes in both garter snakes (Colubridae) and pygmy rattlesnake (Viperidae). Detection of W-linked gametologs enables us to establish the presence of evolutionary strata on garter and pygmy rattlesnake sex chromosomes where recombination was abolished at different time points. Sequence analysis shows that all strata are shared between pygmy rattlesnake and garter snake, i.e., recombination was abolished between the sex chromosomes before the two lineages diverged. The sex-biased transmission of the Z and its hemizygosity in females can impact patterns of molecular evolution, and we show that rates of evolution for Z-linked genes are increased relative to their pseudoautosomal homologs, both at synonymous and amino acid sites (even after controlling for mutational biases). This demonstrates that mutation rates are male-biased in snakes (male-driven evolution), but also supports faster-Z evolution due to differential selective effects on the Z. Finally, we perform a transcriptome analysis in boa and pygmy rattlesnake to establish baseline levels of sex-biased expression in homomorphic sex chromosomes, and show that heteromorphic ZW chromosomes in rattlesnakes lack chromosome-wide dosage compensation. Our study provides the first full scale overview of the evolution of snake sex chromosomes at the genomic level, thus greatly expanding our knowledge of reptilian and vertebrate sex chromosomes evolution.

Amidst Covid-19, young adults have experienced major symptoms of anxiety and/or depression disorder (56%). Mental health issues have been spiking all over the world rapidly. People have taken up to social media as a platform to vent about their mental breakdowns. Twitter has seen enormous rise in depressive and anxious tweets in these times, but the downside being that majority of the population has neglected the importance of mental health issues and there are not enough resources to liberate people about it. Also, people hesitate to talk about their mental issues and seek help. So, a machine learning model using distant supervision to detect depression on Twitter is curated. Use of Sentiment140 dataset with 1.6 million records of different tweets. Our training data makes use of Twitter tweets included with emojis, which are classified as noisy labels on a dataset. Further, this paper mentions about how to use models like Support Vector Machine (SVM), Logistic Regression, Naive Bayes, Random Forest, XGBoost to distinguishing tweets between depressive or nondepressive. The purpose behind using multiple models is to achieve highest accuracy when trained with emoticon dataset. The paper’s main contribution is the idea of using tweets with emoticons for distant supervised learning.

Sorting is the procedure of arranging the elements in ascending or descending order. Sorting algorithms are not only used in computer science but also in our day-to-day life to reduce complexity. For optimizing the use of other algorithms, efficient sorting is required. This paper makes a comparison between merge sort, quick sort, selection sort and insertion sort by their time complexities. [ABSTRACT FROM AUTHOR]

Background: A high level of preoperative anxiety is common among patients undergoing medical and surgical procedures. Anxiety impacts of gastroenterological procedures on psychological and physiological responses are worth consideration. Aims and Objectives: To analyze the effect of listening to Vedic chants and Indian classical instrumental music on anxiety levels and on blood pressure (BP), heart rate (HR), and oxygen saturation in patients undergoing upper gastrointestinal (GI) endoscopy. Materials and Methods: A prospective, randomized controlled trial was done on 199 patients undergoing upper GI endoscopy. On arrival, their anxiety levels were assessed using state and trait scores and various physiological parameters such as HR, BP, and SpO2. Patients were randomly divided into three groups: Group I of 67 patients who were made to listen prerecorded Vedic chants for 10 min, Group II consisting of 66 patients who listened to Indian classical instrumental music for 10 min, and Group III of 66 controls who remained seated for same period in the same environment. Thereafter, their anxiety state scores and physiological parameters were reassessed. Results: A significant reduction in anxiety state scores was observed in the patients in Group I (from 40.4 ± 8.9 to 38.5 ± 10.7; P < 0.05) and Group II (from 41.8 ± 9.9 to 38.0 ± 8.6; P < 0.001) while Group III controls showed no significant change in the anxiety scores. A significant decrease in systolic BP (P < 0.001), diastolic BP (P < 0.05), and SpO2 (P < 0.05 was also observed in Group II. Conclusion: Listening to Vedic chants and Indian classical instrumental music has beneficial effects on alleviating anxiety levels induced by apprehension of invasive procedures and can be of therapeutic use. [ABSTRACT FROM AUTHOR]