743 research outputs found

    DeepColor: Reinforcement Learning optimizes information efficiency and well-formedness in color name partitioning

    Get PDF
    As observed in the World Color Survey (WCS), some universal properties can be identified in color naming schemes over a large number of languages. For example, Regier, Kay, and Khetrapal (2007) and Regier, Kemp, and Kay (2015); Gibson et al. (2017) recently explained these universal patterns in terms of near optimal color partitions and information theoretic measures of efficiency of communication. Here, we introduce a computational learning framework with multi-agent systems trained by reinforcement learning to investigate these universal properties. We compare the results with Regier et al. (2007, 2015) and show that our model achieves excellent quantitative agreement. This work introduces a multi-agent reinforcement learning framework as a powerful and versatile tool to investi- gate such semantic universals in many domains and contribute significantly to central questions in cognitive science

    Comparative study of heart rate variability in normotensive young adults with family history of hypertension

    Get PDF
    Background: Hypertension is a risk factor for the development of cardiovascular and cerebro-vascular diseases. Autonomic nervous system plays a crucial role in the development of hypertension. The integrity of autonomic modulation of heart rate is evaluated by analysing heart rate variability (HRV), which refers to oscillations in the intervals between consecutive heartbeats or R-R intervals. The present study was designed to analyse the indices of heart rate variability in the offsprings of hypertensive parents and off springs of normotensive parents to understand if there is any autonomic imbalance between the two groups.  Methods: The study was conducted in the Department of Physiology, Government Medical College, Srinagar. The test group consisted of 30 healthy normotensive subjects studying in 1st year of MBBS with hypertensive parents and the control group consisted of healthy normotensive of 1st year of MBBS with both parents normotensive. In time domain analysis the standard deviation of all normal-to-normal intervals {SDNN(ms)} was taken as index of overall HRV. Frequency domain analysis was done with respect to low frequency (LF) analysis and high frequency (HF) analysis. Low and high frequency power were expressed in normalized units.Results: The SDNN was reduced in cases but was not statistically significant. RMSSD was also reduced in cases though not statistically significant. LFnu was found to be significantly higher in cases. The HFnu was significantly reduced in cases. LF/HF ratio was found to be higher in cases and the difference was statistically significant.  Conclusions: Our study reveals that incidence of prehypertension and the risk of cardiovascular dysfunction in relation to sympathovagal imbalance is more in the off springs of hypertensive parents than in the off springs of normotensive parents. Sympathovagal imbalance in the form of increased sympathetic drive and decreased parasympathetic drive can lead to prehypertension in these genetically predisposed individuals.

    Exploring critical factors for choice of mobile service providers and its effectiveness on Malaysian consumers

    Get PDF
    From the late 1990 to till now the growth rate of Malaysian telecommunication sector is remarkable manner. Under this circumstances new players to these businesses soaring dramatic business competition. Nowadays they are trying to attract customers by offering aggressive marketing strategy for instance: price promotion. As competition is looming among the companies, it deems a necessity for them to learn the consumers’ inherent perceptions that can play significant factors in terms of choosing the tele-service providers. The aim of this study was to find out what were the factors that may have played significant role to select the telecommunication service providers. To accomplish the objectives, this research explains the related concepts and theories; revealed and synchronized literature on consumer perception. In general this research has an intention to develop a research framework grounded on a strong theoretical and literature review background. The survey instruments employed on Malaysian consumers included demographic background, price, service quality, product quality and availability, and promotional offers for consumer perception. Thus the structural equation modeling approach was necessary in order to examine the variables. The data analysis was conducted using SPSS and AMOS (Analysis of Moment Structure) with the software package for windows. From the result it is revealed that paths are related to the casual processes significantly. Among all the significant variables, from our result, Price is the most important among our respondents followed by Service quality, product quality and promotion. However, the findings of this study may provide needed feedback and contribute to the improvement of players’ strategy and their marketing program

    A reinforcement-learning approach to efficient communication

    Get PDF
    We present a multi-agent computational approach to partitioning semantic spaces using reinforcement-learning (RL). Two agents communicate using a finite linguistic vocabulary in order to convey a concept. This is tested in the color domain, and a natural reinforcement learning mechanism is shown to converge to a scheme that achieves a near-optimal trade-off of simplicity versus communication efficiency. Results are presented both on the communication efficiency as well as on analyses of the resulting partitions of the color space. The effect of varying environmental factors such as noise is also studied. These results suggest that RL offers a powerful and flexible computational framework that can contribute to the development of communication schemes for color names that are near-optimal in an information-theoretic sense and may shape color-naming systems across languages. Our approach is not specific to color and can be used to explore cross-language variation in other semantic domains

    Protein Kinase C Epsilon Overexpression in Prostate Adenocarcinoma is Associated with Oncogenesis

    Get PDF
    Background: PKCε, an isozyme of serine-threonine kinase, has been implicated in epithelial cancer metastasis and progression. This study investigates the impact of the oncogenic PKCε, overexpressed abnormally in human Prostate tumor samples and cell lines, to understand its efficacy. Methods: The microarray dataset, GSE86257, was processed for normalization. The identification of upregulated and downregulated genes was based on FDR >1 and p <0.05 values. Cytoscape analysis and functional enrichment of significant genes were done. The identified genes were validated on the TCGA dataset and survival analysis was performed by Kaplan-Meier analysis. Results: A total of 1524 DEGs were identified with 728 upregulated genes and 818 downregulated genes. The two significant modules with MCODE score:9.0 and Venn analysis provided cyclin-dependent kinase inhibitor protein (CDK1), Cyclin B1 (CCNB1), Phospholipase C Gamma 1 (PLCG1), Cyclin Dependent Kinase 9 (CDK9), Phosphoinositide-3-Kinase Regulatory Subunit 3 (PIK3R3), H4 Clustered Histone 6 (H4C6), Phospholipase C Gamma 2 (PLCG2) as most interacting genes. TCGA data analysis and Prognostic analysis revealed CCNBI, CDK9, and PLCG1 associated with poor prognosis. Conclusion: PKCε regulates genes that are responsible for cancer progression. Therefore, targeting PKCε in Prostate cancer may serve as an important regulatory effect and may improve the prognosis of the disease.&nbsp

    Identification of novel clostridium perfringens type E strains that carry an iota toxin plasmid with a functional enterotoxin gene

    Get PDF
    Clostridium perfringens enterotoxin (CPE) is a major virulence factor for human gastrointestinal diseases, such as food poisoning and antibiotic associated diarrhea. The CPE-encoding gene (cpe) can be chromosomal or plasmid-borne. Recent development of conventional PCR cpe-genotyping assays makes it possible to identify cpe location (chromosomal or plasmid) in type A isolates. Initial studies for developing cpe genotyping assays indicated that all cpe-positive strains isolated from sickened patients were typable by cpe-genotypes, but surveys of C. perfringens environmental strains or strains from feces of healthy people suggested that this assay might not be useful for some cpe-carrying type A isolates. In the current study, a pulsed-field gel electrophoresis Southern blot assay showed that four cpe-genotype untypable isolates carried their cpe gene on a plasmid of ~65 kb. Complete sequence analysis of the ~65 kb variant cpe-carrying plasmid revealed no intact IS elements and a disrupted cytosine methyltransferase (dcm) gene. More importantly, this plasmid contains a conjugative transfer region, a variant cpe gene and variant iota toxin genes. The toxin genes encoded by this plasmid are expressed based upon the results of RT-PCR assays. The ~65 kb plasmid is closely related to the pCPF4969 cpe plasmid of type A isolates. MLST analyses indicated these isolates belong to a unique cluster of C. perfringens. Overall, these isolates carrying a variant functional cpe gene and iota toxin genes represent unique type E strains. © 2011 Miyamoto et al

    Organization of the cpe Locus in CPE-Positive Clostridium perfringens Type C and D Isolates

    Get PDF
    Clostridium perfringens enterotoxin (encoded by the cpe gene) contributes to several important human, and possibly veterinary, enteric diseases. The current study investigated whether cpe locus organization in type C or D isolates resembles one of the three (one chromosomal and two plasmid-borne) cpe loci commonly found amongst type A isolates. Multiplex PCR assays capable of detecting sequences in those type A cpe loci failed to amplify products from cpe-positive type C and D isolates, indicating these isolates possess different cpe locus arrangements. Therefore, restriction fragments containing the cpe gene were cloned and sequenced from two type C isolates and one type D isolate. The obtained cpe locus sequences were then used to construct an overlapping PCR assay to assess cpe locus diversity amongst other cpe-positive type C and D isolates. All seven surveyed cpe-positive type C isolates had a plasmid-borne cpe locus partially resembling the cpe locus of type A isolates carrying a chromosomal cpe gene. In contrast, all eight type D isolates shared the same plasmid-borne cpe locus, which differed substantially from the cpe locus present in other C. perfringens by containing two copies of an ORF with 67% identity to a transposase gene (COG4644) found in Tn1546, but not previously associated with the cpe gene. These results identify greater diversity amongst cpe locus organization than previously appreciated, providing new insights into cpe locus evolution. Finally, evidence for cpe gene mobilization was found for both type C and D isolates, which could explain their cpe plasmid diversity

    Anterior spinal artery syndrome from type A aortic dissection in a patient with Marfan syndrome due to a novel fibrillin mutation

    Get PDF
    Type A aortic dissection is a rare but important cardiac surgical emergency. Few reports exist in the literature describing anterior spinal artery syndrome as a presenting feature. We report a case of anterior spinal artery syndrome due to aortic dissection in a patient with Marfan syndrome caused by a novel fibrillin mutation. A 53-year old female presented with chest pain and sudden-onset paralysis. Neurological examination revealed normal upper limb examination, reduced lower limb power and reflexes but normal sensation. CT scanning revealed type A acute aortic dissection which was treated with emergent cardiac surgical repair. At clinic follow up 3 years later, signs of Marfan syndrome were opportunistically noted and genetic testing revealed a novel mutation in the Fibrillin 1 gene. This case emphasises the importance of a good initial clinical assessment, including thorough neurological examination, as well as a low threshold of clinical suspicion for an aortic dissection in such a constellation of symptoms. The importance of family history should also be emphasised given the coincidental diagnosis of Marfan syndrome in a first-degree relative. Furthermore, this case illustrates the classical signs of anterior spinal artery syndrome

    Seismic Analysis And Design of Cantilever Retaining Walls

    Get PDF
    This project deals with analysis and design with an emphasis laid on effect of earthquake on an important soil retaining structure like cantilever retaining wall. This work also throws light on earthquake damages to retaining structures with help of some case studies. The determination static as well as dynamic earth pressure of cantilever retaining walls will give an idea on the how less intense or severe load combination can result in for a retaining wall to bear it. Retaining walls should be designed for the most onerous load case which could be applied over the lifetime of the structure giving due regard to water table levels and water pressures, parapet loads, consolidation of soils action of by tree roots, collision loads etc. Careful consideration is required to devise all the load cases for which the wall should be designed. The overall stability of the retaining wall against sliding and overturning must be determined prior to construction giving due regard the site soil condition in particular the bearing capacity of the foundation strata based upon the ability of the ground to withstand the combined actions of vertical, horizontal and rotational loading that the wall transfers to the ground

    Carbohydrate restriction for glycemic control in Type 2 diabetes : a systematic review and meta-analysis

    Get PDF
    Aim To conduct a systematic review and meta‐analysis to evaluate the effect of carbohydrate restriction on glycaemic control in Type 2 diabetes. Methods We searched Medline, EMBASE and CINAHL for the period between 1976 and April 2018. We included randomized controlled trials comparing carbohydrate restriction with a control diet which aimed to maintain or increase carbohydrate intake, and that reported HbA1c as an outcome and reported the amount of carbohydrate consumed during or at the end of the study, with outcomes reported at ≥3 months. Results We identified 1402 randomized controlled trials, 25 of which met the inclusion criteria, incorporating 2132 participants for the main outcome. Definitions of low carbohydrate varied among the studies. The pooled effect estimate from meta‐analysis was a weighted mean difference of –0.09% [95% CI –0.27, 0.08 (P = 0.30); I2 72% (P <0.001)], suggesting no effect on HbA1c of restricting the quantity of carbohydrate. A subgroup analysis of diets containing 50–130 g carbohydrate resulted in a pooled effect estimate of –0.49% [95% CI –0.75, –0.23 (P <0.001); I2 0% (P = 0.56)], suggesting a clinically and statistically significant effect on HbA1c in favour of low‐carbohydrate diets in studies of ≤6 months’ duration. Conclusions There was no overall pooled effect on HbA1c in favour of restricting carbohydrate; however, restriction of carbohydrate to 50–130 g per day had beneficial effects on HbA1c in trials up to 6 months. Future randomized controlled trials should be of >12 months’ duration, assess pre‐study carbohydrate intake, use recognized definitions of low‐carbohydrate diets and examine reasons for non‐concordance in greater detail
    corecore