Upper bounds on the superfluid stiffness and superconducting TcT_c: Applications to twisted-bilayer graphene and ultra-cold Fermi gases

Understanding the material parameters that control the superconducting transition temperature $T_c$ is a problem of fundamental importance. In many novel superconductors, phase fluctuations determine $T_c$, rather than the collapse of the pairing amplitude. We derive rigorous upper bounds on the superfluid phase stiffness for multi-band systems, valid in any dimension. This in turn leads to an upper bound on $T_c$ in two dimensions (2D), which holds irrespective of pairing mechanism, interaction strength, or order-parameter symmetry. Our bound is particularly useful for the strongly correlated regime of low-density and narrow-band systems, where mean field theory fails. For a simple parabolic band in 2D with Fermi energy $E_F$, we find that $k_BT_c \leq E_F/8$, an exact result that has direct implications for the 2D BCS-BEC crossover in ultra-cold Fermi gases. Applying our multi-band bound to magic-angle twisted bilayer graphene (MA-TBG), we find that band structure results constrain the maximum $T_c$ to be close to the experimentally observed value. Finally, we discuss the question of deriving rigorous upper bounds on $T_c$ in 3D.Comment: Revised figures, includes estimates from another model of MA-TBG, published version of manuscrip

Branching and size of CTAB-coated gold nanostars control the colorimetric detection of bacteria

Rapid detection of pathogenic bacteria is challenging because conventional methods require long incubation times. Nanoparticles have the potential to detect pathogens before they can cause an infection. Gold nanostars have recently been used for colorimetric biosensors but they typically require surface modification with antibodies or aptamers for cellular detection. Here, CTAB-coated gold nanostars have been used to rapidly (<5 min) detect infective doses of a model Gram-positive pathogen Staphylococcus aureus by an instrument-free colorimetric method. Varying the amounts of gold nanoseed precursor and surfactant can tune the size and degree of branching of gold nanostars as studied here by transmission electron microscopy. The size and morphology of gold nanostars determine the degree and rate of color change in the presence of S. aureus. The optimal formulation achieved maximum color contrast in the presence of S. aureus and produced a selective response in comparison to polystyrene microparticles and liposomes. These gold nanostars were characterized using UV-Visible spectroscopy to monitor changes in their surface plasmon resonance peaks. The visual color change was also quantified over time by measuring the RGB components of the pixels in the digital images of gold nanostar solutions. CTAB-coated gold nanostars serve as a promising material for simple and rapid detection of pathogens.This work was financially supported by the Natural Sciences and Engineering Research Council of Canada (NSERC)and 20/20 NSERC Ophthalmic Materials Network.M. S. Verma is grateful for the NSERC Vanier Canada Graduate Scholarship.P. Z. Chen is thankful for the NSERC Undergraduate Student Research Award

Genetic Algorithms: Usefulness and Effectiveness for Pattern Recognition

Genetic Algorithms have been gaining much interest since the early 1970\u27s and have intrigued people from the fields of machine learning, artificial intelligence, neural networks and operations research. This paper describes the approach of genetic algorithms applied to neural networks. The experiments were conducted using various functions such as XOR,AND,SINE and different network sizes. Based on the experimental data, we concluded that for small network architectures represented by the functions (SINE,ENCODE,etc), genetic algorithms were not effective and the desired results were not achieved within a reasonable period of time

Genome-wide Profiling of RNA splicing in prostate tumor from RNA-seq data using virtual microarrays

BACKGROUND: Second generation RNA sequencing technology (RNA-seq) offers the potential to interrogate genome-wide differential RNA splicing in cancer. However, since short RNA reads spanning spliced junctions cannot be mapped contiguously onto to the chromosomes, there is a need for methods to profile splicing from RNA-seq data. Before the invent of RNA-seq technologies, microarrays containing probe sequences representing exon-exon junctions of known genes have been used to hybridize cellular RNAs for measuring context-specific differential splicing. Here, we extend this approach to detect tumor-specific splicing in prostate cancer from a RNA-seq dataset. METHOD: A database, SPEventH, representing probe sequences of under a million non-redundant splice events in human is created with exon-exon junctions of optimized length for use as virtual microarray. SPEventH is used to map tens of millions of reads from matched tumor-normal samples from ten individuals with prostate cancer. Differential counts of reads mapped to each event from tumor and matched normal is used to identify statistically significant tumor-specific splice events in prostate. RESULTS: We find sixty-one (61) splice events that are differentially expressed with a p-value of less than 0.0001 and a fold change of greater than 1.5 in prostate tumor compared to the respective matched normal samples. Interestingly, the only evidence, EST (BF372485), in the public database for one of the tumor-specific splice event joining one of the intron in KLK3 gene to an intron in KLK2, is also derived from prostate tumor-tissue. Also, the 765 events with a p-value of less than 0.001 is shown to cluster all twenty samples in a context-specific fashion with few exceptions stemming from low coverage of samples. CONCLUSIONS: We demonstrate that virtual microarray experiments using a non-redundant database of splice events in human is both efficient and sensitive way to profile genome-wide splicing in biological samples and to detect tumor-specific splicing signatures in datasets from RNA-seq technologies. The signature from the large number of splice events that could cluster tumor and matched-normal samples into two tight separate clusters, suggests that differential splicing is yet another RNA phenotype, alongside gene expression and SNPs, that can be exploited for tumor stratification

Combining ability analysis in linseed (Linum usitatissimum L.) for improvement of seed yield and its component traits

Twenty eight hybrids developed from eight genotypes of linseed through diallel mating design (excluding reciprocal) along with one checks viz., Shekhar were evaluated in randomized block design with three replications for eleven distinct morphological traits during rabi season of 2012-13, to estimate the general combining ability (GCA) of the parents and specific combining ability (SCA) of hybrids considered for the development of high yielding varieties. The analysis of variance for combining ability revealed significant mean sum of squares due to GCA and SCA for all the traits under study. Genotype EC-1392 (0.50) and TL-11 (0.45) has been found good general combiner with highest magnitude of GCA effects for seed yield per plant. In addition to above, EC-1392 and TL-11 also showed good GCA effects for plant height, secondary branches per plant, capsules per plant and biological yield per plant. Hybrids A.95.B x Shekhar (2.43), TL-11 x EC-1392 (1.71) and NDL-2004-05 x GS-234 (1.53) showed higher positive significant SCA effects for seed yield per plant. These hybrids also exhibited positive significant SCA effects for plant height, secondary brances per plant, capsules per plant, indicating potential for exploiting hybrid vigour in breeding programme

Nucleic Acid Detection of Live Pathogens on Contaminated Foods

The goal is to develop a point-of-care biosensor for the detection of live pathogens contaminating beef products. Biosensing of live pathogens is based on isothermal amplification of nucleic acid on a paper-based device. A colorimetric dye is employed as an indicator of the amplification product for visual result. The assay incorporates a compound Propidium monoazide (PMA) that makes the DNA from dead cells inaccessible for amplification. This approach is especially applicable for pathogens that can enter a viable but non-culturable state (VBNC)

Envisioning the Future: Post-Pandemic Content Strategy for Destination Marketing Organizations

The highly contagious nature of the novel Coronavirus locks-unlocks and economic uncertainty around the world have changed the complete landscape of the tourism sector. To attract tourists, it is necessary to revise the content strategy of Destination Marketing Organizations (DMOs) in the post-Covid economy. This study explores how different characteristics of DMO’s social media posts influence tourists’ online engagement. We used 876 posts from July 2021 to June 2022 on the official Facebook handle of Incredible India, through which we assessed the tourists’ ‘engagement’, using the number of likes, comments, and shares. Additionally, linguistic features-based categorization of posts was done using LIWC. The results demonstrate that message format, message appeal, motives, and time orientation of posts significantly influence the tourists’ online engagement. These findings are relevant to information dissemination and provide valuable insights for DMOs. DMOs could use this study to design their future messages to gather maximum engagement through social media posts

Environmental Responsibilities and Firms Financial Performance: A Systematic Review and Bibliometric Analysis

The aim of this study is to present a systematic review and bibliometric analysis of 512 studies on environmental responsibilities and firm financial performance literature. The study aims to track the research trend and identify the reasons behind heterogeneity in the studied association. The Scopus database was comprehensively searched to collect bibliographic material, giving an overview of contributing and influential research areas, key authors, journals, and countries. Network visualization is used to identify clusters. Content analysis of the literature revealed the essential topics of the investigation. The systematic review revealed that geographical constraints, regulatory constraints, and lack of standardizability are significant reasons for heterogeneity. We identify three major researched areas: a) economic and financial impact, b) innovation, environment management system, and standards, and c) supply chain management development. Discussion on the signifi cant clusters concludes that studies showing positive economic benefits dominate the literature. Overall, the results of different scientific production do not indicate consensus in one direction, but mixed results help to build a new perspective and expand the research horizon. Using a systematic process, this study recognizes the value-creation potential of proactive environmental management practices

Effect of Carbohydrates on the Gut Microbiome

The microbiome within the gut is directly linked to biological processes within a person, influencing factors such as metabolism, signaling pathways, and available nutrients. Long term dieting is known to alter ecological conditions within the gut, allowing certain types of microbes to flourish. Therefore, the overall health of an individual is ultimately influenced by shifts in the microbial community state caused by persistent dieting. This study investigates the connection between diet and the microbiome and draws an understanding of how common carbohydrates in food can affect bacterial composition. Using KBase software, anaerobic bacterial growth was investigated for bacteria subject to a defined media with distinct sugars. Common bacteria found in young children were studied as microbiome development begins post-partum. The results show that only certain carbohydrates have a crucial impact on bacterial growth while others are inert. In future studies, it is recommended that co-cultures of bacteria are studied in the sugar additive media to determine relative abundance and how different bacterial strains can dominate one another