270 research outputs found

    A heuristics approach for computing the largest eigenvalue of a pairwise comparison matrix

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    Pairwise comparison matrices (PCMs) are widely used to capture subjective human judgements, especially in the context of the Analytic Hierarchy Process (AHP). Consistency of judgements is normally computed in AHP context in the form of consistency ratio (CR), which requires estimation of the largest eigenvalue (Lmax) of PCMs. Since many of these alternative methods do not require calculation of eigenvector, Lmax and hence the CR of a PCM cannot be easily estimated. We propose in this paper a simple heuristics for calculating Lmax without any need to use Eigenvector Method (EM). We illustrated the proposed procedure with larger size matrices. Simulation is used to compare the accuracy of the proposed heuristics procedure with actual Lmax for PCMs of various sizes. It has been found that the proposed heuristics is highly accurate, with errors less than 1%. The proposed procedure would avoid biases and help managers to make better decisions. The advantage of the proposed heuristics is that it can be easily calculated with simple calculations without any need for specialised mathematical procedures or software and is independent of the method used to derive priorities from PCMs

    On the nature of the spore-appendage in Neottiospora Desm.

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    Anthasthoopa, a new genus of the Sphæropsidales

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    TEXTRON: Weakly Supervised Multilingual Text Detection through Data Programming

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    Several recent deep learning (DL) based techniques perform considerably well on image-based multilingual text detection. However, their performance relies heavily on the availability and quality of training data. There are numerous types of page-level document images consisting of information in several modalities, languages, fonts, and layouts. This makes text detection a challenging problem in the field of computer vision (CV), especially for low-resource or handwritten languages. Furthermore, there is a scarcity of word-level labeled data for text detection, especially for multilingual settings and Indian scripts that incorporate both printed and handwritten text. Conventionally, Indian script text detection requires training a DL model on plenty of labeled data, but to the best of our knowledge, no relevant datasets are available. Manual annotation of such data requires a lot of time, effort, and expertise. In order to solve this problem, we propose TEXTRON, a Data Programming-based approach, where users can plug various text detection methods into a weak supervision-based learning framework. One can view this approach to multilingual text detection as an ensemble of different CV-based techniques and DL approaches. TEXTRON can leverage the predictions of DL models pre-trained on a significant amount of language data in conjunction with CV-based methods to improve text detection in other languages. We demonstrate that TEXTRON can improve the detection performance for documents written in Indian languages, despite the absence of corresponding labeled data. Further, through extensive experimentation, we show improvement brought about by our approach over the current State-of-the-art (SOTA) models, especially for handwritten Devanagari text. Code and dataset has been made available at https://github.com/IITB-LEAP-OCR/TEXTRONComment: Accepted at the WACV 2024 Conferenc

    Glycerol conversion to 1, 3-Propanediol is enhanced by the expression of a heterologous alcohol dehydrogenase gene in Lactobacillus reuteri

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    In this work, Lactobacillus reuteri has been metabolically engineered for improving 1, 3-propanediol (1, 3-PD) production by the expression of an Escherichia coli alcohol dehydrogenase, yqhD, that is known to efficiently convert the precursor 3-hydroxypropionaldehyde (3-HPA) to 1, 3-PD. The engineered strain exhibited significantly altered formation rates for the product and other metabolites during the fermentation. An increase in the 1, 3-PD specific productivity of 34% and molar yield by 13% was achieved in the clone, relative to the native strain. A concomitant decrease in the levels of toxic intermediate, 3-HPA, was observed, with the specific productivity levels being 25% lesser than that of the native strain. Interestingly, the recombinant strain exhibited elevated rates of lactate and ethanol formation as well as reduced rate of acetate production, compared to the native strain. The preferential utilization of NADPH by YqhD with a possible decrease in the native 1, 3-PD oxidoreductase (NADH-dependent) activity, could have resulted in the diversion of surplus NADH towards increased lactate and ethanol productivities

    Chemical and Physicochemical Pretreatment of Lignocellulosic Biomass: A Review

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    Overcoming the recalcitrance (resistance of plant cell walls to deconstruction) of lignocellulosic biomass is a key step in the production of fuels and chemicals. The recalcitrance is due to the highly crystalline structure of cellulose which is embedded in a matrix of polymers-lignin and hemicellulose. The main goal of pretreatment is to overcome this recalcitrance, to separate the cellulose from the matrix polymers, and to make it more accessible for enzymatic hydrolysis. Reports have shown that pretreatment can improve sugar yields to higher than 90% theoretical yield for biomass such as wood, grasses, and corn. This paper reviews different leading pretreatment technologies along with their latest developments and highlights their advantages and disadvantages with respect to subsequent hydrolysis and fermentation. The effects of different technologies on the components of biomass (cellulose, hemicellulose, and lignin) are also reviewed with a focus on how the treatment greatly enhances enzymatic cellulose digestibility

    Utjecaj pojačane ekspresije gena biosintetskog puta za 3-hidroksipropionsku kiselinu na njezin prinos u bakteriji Lactobacillus reuteri

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    3-Hydroxypropionic acid (3-HP) is a novel antimicrobial agent against foodborne pathogens like Salmonella and Staphylococcus species. Lactobacillus reuteri converts glycerol into 3-HP using a coenzyme A-dependent pathway, which is encoded by propanediol utilization operon (pdu) subjected to catabolite repression. In a catabolite repression-deregulated L. reuteri RPRB3007, quantitative PCR revealed a 2.5-fold increase in the transcripts of the genes pduP, pduW and pduL during the mid-log phase of growth. The production of 3-HP was tested in resting cells in phosphate buff er and growing batch cultures in MRS broth of various glucose/glycerol ratios. Due to the upregulation of pathway genes, specific formation rate of 3-HP in the mutant strain was found to be enhanced from 0.167 to 0.257 g per g of cell dry mass per h. Furthermore, formation of 3-HP in resting cells was limited due to the substrate inhibition by reuterin at a concentration of (30±5) mM. In batch cultures, the formation of 3-HP was not observed during the logarithmic and stationary phases of growth of wild-type and mutant strains, which was confi rmed by NMR spectroscopy. However, the cells collected in these phases were found to produce 3-HP aft er washing and converting them to resting cells. Lactate and acetate, the primary end products of glucose catabolism, might be the inhibiting elements for 3-HP formation in batch cultures. This was confirmed when lactate (25±5 mM) or acetate (20±5 mM) were added to biotransformation medium, which prevented the 3-HP formation. Moreover, the removal of sodium acetate and glucose (carbon source for lactic acid production) was found to restore 3-HP formation in the MRS broth in a similar manner to that of the phosphate buff er. Even though the genetic repression was circumvented by the up-regulation of pathway genes using a mutant strain, 3-HP formation was further limited by the substrate and catabolite inhibition.3-Hidroksipropionska kiselina je novi antimikrobni agens koji se može upotrijebiti za suzbijanje patogenih bakterija u hrani, kao što su vrste iz rodova Salmonella i Staphylococcus. Bakterija Lactobacillus reuteri iz glicerola sintetizira 3-hidroksipropionsku kiselinu biosintetskim putem ovisnim o koenzimu A, kodiranim operonom za korištenje propandiola koji je reguliran kataboličkom represijom. U mutantu L. reuteri RPRB3007 u kojem nema kataboličke represije, ispitanom pomoću metode PCR, primijećeno je 2,5 puta više transkripata gena pduP, pduW i pduL, i to tijekom logaritamske faze rasta bakterije. Proizvodnja 3-hidroksipropionske kiseline određena je u stanicama koje se ne dijele, a bile su resuspendirane u fosfatnom puferu, te u šaržnim kulturama uzgojenim u podlozi MRS s različitim omjerima glukoze i glicerola. Utvrđeno je da se u mutantu zbog pojačane ekspresije gena biosintetskog puta povećala specifična brzina nastajanja 3-hidroksipropionske kiseline, i to s 0,167 na 0,257 g po gramu suhe biomase po satu. Osim toga, sinteza je 3-hidroksipropionske kiseline u stanicama koje se ne dijele bila usporena nakon dodatka reuterina u koncentraciji od (30±5) mM. U šaržnom uzgoju nije utvrđena prisutnost 3-hidroksipropionske kiseline tijekom logaritamske i stacionarne faze rasta divljeg soja i mutanta, što je potvrđeno i NMR spektroskopijom. Međutim, nakon ispiranja i povratka u stanje mirovanja ove su stanice ponovno proizvodile 3-hidroksipropionsku kiselinu. Zaključeno je da laktat i acetat, primarni produkti katabolizma glukoze, vjerojatno inhibiraju sintezu 3-hidroksipropionske kiseline u šaržnim kulturama, što je potvrđeno činjenicom da dodatak laktata u koncentraciji od (25±5) mM ili acetata u koncentraciji od (20±5) mM podlozi sprečava sintezu 3-hidroksipropionske kiseline. Osim toga, uklanjanjem je natrijevog acetata i glukoze (izvora ugljika za proizvodnju mliječne kiseline) potaknuta proizvodnja 3-hiroksipropionske kiseline u hranjivoj podlozi MRS na sličan način kao i uporabom fosfatnog pufera. Iako je genetička represija u mutantu izbjegnuta pojačanom ekspresijom gena biosintetskog puta, proizvodnja je 3-hidroksipropionske kiseline i dalje bila ograničena supstratom i kataboličkom inhibicijom
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