Differences in early and late pattern-onset visual-evoked potentials between self-reported migraineurs and controls

Striped patterns have been shown to induce strong visual illusions and discomforts to migraineurs in previous literature. Previous research has suggested that these unusual visual symptoms to be linked with the hyperactivity on the visual cortex of migraine sufferers. The present study searched for evidence supporting this hypothesis by comparing the visual evoked potentials (VEPs) elicited by striped patterns of specific spatial frequencies (0.5, 3, and 13 cycles-per-degree) between a group of 29 migraineurs (17 with aura/12 without) and 31 non-migraineurs. In addition, VEPs to the same stripped patterns were compared between non-migraineurs who were classified as hyperexcitable versus non-hyperexcitable using a previously established behavioural pattern glare task. We found that the migraineurs had a significantly increased N2 amplitude for stimuli with 13 cpd gratings but an attenuated late negativity (LN: 400 - 500 ms after the stimuli onset) for all the spatial frequencies. Interestingly, non-migraineurs who scored as hyperexcitable appeared to have similar response patterns to the migraineurs, albeit in an attenuated form. We propose that the enhanced N2 could reflect disruption of the balance between parvocellular and magnocellular pathway, which is in support of the cortical hyperexcitation hypothesis in migraineurs. In addition, the attenuation of the late negativity could reflect a top-down feedback mechanism to suppress visual processing of an aversive stimulus

Attenuated alpha oscillation and hyperresponsiveness reveals impaired perceptual learning in migraineurs.

Background: Anomalous phantom visual perceptions coupled to an aversion and discomfort to some visual patterns (especially grating in mid-range spatial frequency) have been associated with the hyperresponsiveness in migraine patients. Previous literature has found fluctuations of alpha oscillation (8-14 Hz) over the visual cortex to be associated with the gating of the visual stream. In the current study, we examined whether alpha activity was differentially modulated in migraineurs in anticipation of an upcoming stimulus as well as post-stimulus periods. Methods: We used EEG to examine the brain activity in a group of 28 migraineurs (17 with aura/11 without) and 29 non-migraineurs and compared their alpha power in the pre/post-stimulus period relative to the onset of stripped gratings. Results: Overall, we found that migraineurs had significantly less alpha power prior to the onset of the stimulus relative to controls. Moreover, migraineurs had significantly greater post-stimulus alpha suppression (i.e event-related desynchronization) induced by the grating in 3 cycles per degree at the 2nd half of the experiment. Conclusions: These findings taken together provide strong support for the presence of the hyperresponsiveness of the visual cortex of migraine sufferers. We speculate that it could be the consequence of impaired perceptual learning driven by the dysfunction of GABAergic inhibitory mechanism

A Gramaticalização do Verbo Ir e a Variação de Formas para Expressar o Futuro do Presente: uma Fotografia Capixaba

Esta pesquisa verifica o estágio do processo de gramaticalização do verbo IR, que tem assumido a função de auxiliar em construções perifrásticas para expressar tempo. Para isso, investiga-se a variação entre as formas sintética e perifrástica com IR para expressão do futuro do presente. Temos por hipótese que a forma perifrástica já atinge todos os gêneros das duas modalidades da língua, uma vez que já se especializou para codificar tempo. São examinados dois gêneros, tomando-os como prototípicos do continuun oral/escrito: entrevistas com informantes universitários e editoriais de jornal. Partindo de uma orientação teórica Funcionalista, num quadro mais geral, concebe-se a língua como flexível ao uso, passível de influências cognitivas, sociais e também individuais, embora haja nela forças que atuam no sentido de regularizar a estrutura. Seguindo algumas pesquisas que têm se mostrado frutíferas, o modelo funcionalista estará em diálogo com outro modelo que procura dar conta da heterogeneidade estruturada da língua e de seus processos de mudança: a Teoria Variacionista. Num quadro mais específico, os fundamentos que orientam a pesquisa são os da Gramaticalização. Os dados extraídos dos gêneros selecionados serão submetidos ao programa computacional GOLDVARB 2001 e, em seguida, interpretados à luz das teorias lingüísticas que fundamentam esta pesquisa

MICA: A fast short-read aligner that takes full advantage of Many Integrated Core Architecture (MIC)

Background: Short-read aligners have recently gained a lot of speed by exploiting the massive parallelism of GPU. An uprising alterative to GPU is Intel MIC; supercomputers like Tianhe-2, currently top of TOP500, is built with 48,000 MIC boards to offer ~55 PFLOPS. The CPU-like architecture of MIC allows CPU-based software to be parallelized easily; however, the performance is often inferior to GPU counterparts as an MIC card contains only ~60 cores (while a GPU card typically has over a thousand cores). Results: To better utilize MIC-enabled computers for NGS data analysis, we developed a new short-read aligner MICA that is optimized in view of MIC's limitation and the extra parallelism inside each MIC core. By utilizing the 512-bit vector units in the MIC and implementing a new seeding strategy, experiments on aligning 150 bp paired-end reads show that MICA using one MIC card is 4.9 times faster than BWA-MEM (using 6 cores of a top-end CPU), and slightly faster than SOAP3-dp (using a GPU). Furthermore, MICA's simplicity allows very efficient scale-up when multiple MIC cards are used in a node (3 cards give a 14.1-fold speedup over BWA-MEM). Summary: MICA can be readily used by MIC-enabled supercomputers for production purpose. We have tested MICA on Tianhe-2 with 90 WGS samples (17.47 Tera-bases), which can be aligned in an hour using 400 nodes. MICA has impressive performance even though MIC is only in its initial stage of development. Availability and implementation: MICA's source code is freely available at http://sourceforge.net/projects/mica-aligner under GPL v3. Supplementary information: Supplementary information is available as "Additional File 1". Datasets are available at www.bio8.cs.hku.hk/dataset/mica.published_or_final_versio

Fine Mapping of the NRG1 Hirschsprung's Disease Locus

The primary pathology of Hirschsprung's disease (HSCR, colon aganglionosis) is the absence of ganglia in variable lengths of the hindgut, resulting in functional obstruction. HSCR is attributed to a failure of migration of the enteric ganglion precursors along the developing gut. RET is a key regulator of the development of the enteric nervous system (ENS) and the major HSCR-causing gene. Yet the reduced penetrance of RET DNA HSCR-associated variants together with the phenotypic variability suggest the involvement of additional genes in the disease. Through a genome-wide association study, we uncovered a ∼350 kb HSCR-associated region encompassing part of the neuregulin-1 gene (NRG1). To identify the causal NRG1 variants contributing to HSCR, we genotyped 243 SNPs variants on 343 ethnic Chinese HSCR patients and 359 controls. Genotype analysis coupled with imputation narrowed down the HSCR-associated region to 21 kb, with four of the most associated SNPs (rs10088313, rs10094655, rs4624987, and rs3884552) mapping to the NRG1 promoter. We investigated whether there was correlation between the genotype at the rs10088313 locus and the amount of NRG1 expressed in human gut tissues (40 patients and 21 controls) and found differences in expression as a function of genotype. We also found significant differences in NRG1 expression levels between diseased and control individuals bearing the same rs10088313 risk genotype. This indicates that the effects of NRG1 common variants are likely to depend on other alleles or epigenetic factors present in the patients and would account for the variability in the genetic predisposition to HSCR

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Efficient analysis solution for DNA short-read sequencing

In recent years, the demand for DNA sequencing analysis has been boosted with the advance of DNA sequencing technologies; exceeding the capacities of high-end computer servers. This thesis presents integrated software solutions for popular DNA Sequencing analyses, along with implementation and experiments with real data to demonstrate the strength of the solutions over conventional solutions. The first software tool presented is BALSA, which integrates the DNA pairend short reads aligner SOAP3-dp with a newly designed secondary analysis. BALSA finishes 30x Whole-Genome Analysis (WGA) within 6 hours. The well-known pipeline BWA+GATK takes about 20 hours for the same analysis. BALSA’s efficiency is rooted at its fast alignment algorithm and an integrated design that significantly reduces the time spent on file IO. More importantly, experiments show that variant calling accuracy and sensitivity of BALSA are competitive to other existing solutions. The second tool presented is BALSA-Amplicon, which is designed for amplicon sequencing analysis. Unlike WGA, amplicon sequencing data come along with artificial primers, which will contaminate the analysis. A common fix is to trim the reads at the beginning, but this also removes useful data that helps to map the read correctly. BALSA takes advantage of aligning with the primer and only trims it when updating the in-memory alignment information data structure. The sequencing depth of amplicon data could also be several thousands of times of that of WGA data. The data structure has been modified to support the high sequencing depth without degrading the performance. Experiments show BALSA-amplicon takes 20 minutes for calling variants from 3 million of 275bp amplicon short-read pairs. Thirdly, we introduce a short-read aligner SOAP4, targeted on aligning short-read pairs with read length larger than or equal to 150bp (the current standard of high-throughput sequencers like HiSeq 10X). Unlike 100bp reads, the number of mismatches along the reads are generally greater than 2. SOAP3-dp is unable to be aligned quickly by using BWT index solely. SOAP4 highly adapts the seed-and-extend strategy. Experiments, with real data with 250bp length, show that SOAP4 is 8% faster than SOAP3-dp and the sensitivity of SOAP4 is 95.83%, compared to 85.32% of SOAP3-dp. And simulated data experiments show SOAP4 gives competitive accuracy compare with SOAP3-dp. Lastly, we introduce the tool ELSA, CPU-version BALSA. ELSA tries to compensate a GPU card (which typically contains hundreds to a few thousand cores) by multiple-cores CPUs in a single computing node (typically 2x12 cores). Although GPU is a popular tool in the aspect of high-performance computing, it is costly and requires special maintenance especially on its evolving software environment. ELSA is targeted to be a cost-effective solution for secondary analysis.published_or_final_versionComputer ScienceMasterMaster of Philosoph

Younger adults tolerate more relational risks in everyday life as revealed by the general risk-taking questionnaire

Abstract A range of self-report questionnaires were developed to quantify one’s risk-taking (RT) tendency. Exploring people’s perceived risk level associated with negative risk behaviors is essential to develop a better understanding and intervention policies for RT. In the present study, we proposed a 2 × 10-item scale, namely, the general risk-taking questionnaire (GRTQ), to evaluate RT tendency and risk attitude among the general population by measuring people’s engagement in and perceptions toward 10 commonly known risky behaviors. A total of 2984 adults residing in 10 prefectures in Japan (age range = 20–59, 53.12% female) provided valid responses to an online survey. Apart from the factor analysis procedures, multivariate negative binomial regression models have been applied to investigate the relationship between RT engagement and perception. We obtained two identical factors, namely, personal risk and relational risk, for both scales of the GRTQ. Increased levels of RT engagement were found in younger, male, nonmarried, nonparent and urban respondents. Despite an overall negative correlation between RT engagement and perception, our model revealed a weaker linkage in the younger population for relational risk behaviors. Overall, we showed evidence that the GRTQ is an easy-to-administer, valid and reliable measure of RT for future clinical research

Online learning in management education amid the pandemic: a bibliometric and content analysis

The COVID-19 pandemic (2020–2022) had triggered a global crisis which led to the suspension of colleges and universities. Management educators had digitally transformed their teaching to new modalities with digital technologies and adapted to technological solutions. The management students had experienced different online modes of learning and adjusted their methods to the new reality of content delivery. This study aims to discuss opportunities and challenges for management education and facilitate further investigation into the emerging trends on online learning by analyzing the characteristics of management education research and examining the most frequent research themes from 2020 to 2022. A bibliometric analysis is used to review 920 papers retrieved from the Scopus database for exploring key research themes of management education and online learning. The findings revealed that the publications are concentrated in developed countries while European countries had accounted for the largest proportion of the listed publications. Five sub themes are identified for receiving the most scholarly attention, such as pedagogy, technology, assessment methods, learning outcomes or skills, and challenges. After all, the bibliometric and thematic findings identified pivotal theoretical contributions, including fields of online or blended learning and management education converge, to extend the existing online learning theories