754 research outputs found

    Analytically weak solutions to SPDEs with unbounded time-dependent differential operators and an application

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    We analyze the concepts of analytically weak solutions of stochastic differential equations (SDEs) in Hilbert spaces with time-dependent unbounded operators and give conditions for existence and uniqueness of such solutions. Our studies are motivated by a stochastic partial differential equation (SPDE) arising in industrial mathematics

    Influence of an upper layer liquid on the phenomena and cavity formation associated with the entry of solid spheres into a stratified, two-layer system of immiscible liquids

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    New phenomena not previously documented in the available literature have been experimentally observed subsequent to the entry of falling steel spheres into a stratified system of a shallow layer of sunflower oil above a deep pool of water. Further experiments on similar sphere entries into sunflower oil demonstrated that these phenomena arose mainly as a result of the interaction between the surface of the spheres and the sunflower oil. It should be noted that the sunflower oil layer in the aforementioned two-layer system was relatively very thin compared to the dimensions of the spheres. Therefore, the experiments showed the substantial influence both the upper layer liquid and the surface conditions of the solid body could potentially have on the phenomena and cavity dynamics that arise as a result of solid entries into stratified two-layer systems of immiscible liquids

    Length heterogeneity at conserved sequence block 2 in human mitochondrial DNA acts as a rheostat for RNA polymerase POLRMT activity

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    The guanine (G)-tract of conserved sequence block 2 (CSB 2) in human mitochondrial DNA can result in transcription termination due to formation of a hybrid G-quadruplex between the nascent RNA and the nontemplate DNA strand. This structure can then influence genome replication, stability and localization. Here we surveyed the frequency of variation in sequence identity and length at CSB 2 amongst human mitochondrial genomes and used in vitro transcription to assess the effects of this length heterogeneity on the activity of the mitochondrial RNA polymerase, POLRMT. In general, increased G-tract length correlated with increased termination levels. However, variation in the population favoured CSB 2 sequences which produced efficient termination while particularly weak or strong signals were avoided. For all variants examined, the 3′ end of the transcripts mapped to the same downstream sequences and were prevented from terminating by addition of the transcription factor TEFM. We propose that CSB 2 length heterogeneity allows variation in the efficiency of transcription termination without affecting the position of the products or the capacity for regulation by TEFM

    An experimental study on the entry of spheres into a two-layer system of immiscible liquids

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    The phenomena, cavity formations and dynamics associated with rigid spheres entering into stratified, two-layer, oil-water systems were experimentally studied. The results were compared with available data for the corresponding type of cavities formed by spheres entering into single-phase, homogeneous liquids. The discussion and data analysis showed that the oil coating acquired by the spheres while passing through the oil layer, significantly modified the qualitative and quantitative aspects of the dynamics associated with cavity formation. In particular, ripple-like structures were discovered forming along the cavity walls, and such phenomenon was not known to exist when spheres entered into homogeneous liquids. The data analysis also showed that the ripples formed as a result of a two-dimensional instability, arising due to the shear between the oil layer coating the spheres and the surrounding water. Meanwhile, phenomena not consistent with present understanding were observed during entries of steel spheres into sunflower oil and the two-layer, sunflower oil-water system. Further experiments suggested that such phenomena arose as a result of the surface conditions of the spheres, thereby highlighting the substantial influence the surface conditions of a body could potentially have on cavity dynamics

    Applying Stakeholder and Self-Efficacy Theories to Classify Organizational Citizenship Behavior Antecedents

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    Most studies about organizational citizenship behavior (OCB) focus on particular actions that employees, supervisors, or owners of organizations should exhibit. To encourage OCB in service-oriented Filipino organizations, this paper proposes a classification of OCB antecedents collected from the literature in theory and industry practice. By using the stakeholder and self-efficacy theories, the proposed four clearly defined categories point out whether these antecedents are employee-led, leader-led, organization-led, or HR-led initiatives. Since it would be burdensome for an individual to know all the factors that may influence OCB, categorizing these antecedents will help the individual to identify the behavioral aspects that he or she has control over. Managerial implications are also discussed

    Gelsolin induces colorectal tumor cell invasion via modulation of the urokinase-type plasminogen activator cascade

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    Gelsolin is a cytoskeletal protein which participates in actin filament dynamics and promotes cell motility and plasticity. Although initially regarded as a tumor suppressor, gelsolin expression in certain tumors correlates with poor prognosis and therapy-resistance. In vitro, gelsolin has anti-apoptotic and pro-migratory functions and is critical for invasion of some types of tumor cells. We found that gelsolin was highly expressed at tumor borders infiltrating into adjacent liver tissues, as examined by immunohistochemistry. Although gelsolin contributes to lamellipodia formation in migrating cells, the mechanisms by which it induces tumor invasion are unclear. Gelsolin’s influence on the invasive activity of colorectal cancer cells was investigated using overexpression and small interfering RNA knockdown. We show that gelsolin is required for invasion of colorectal cancer cells through matrigel. Microarray analysis and quantitative PCR indicate that gelsolin overexpression induces the upregulation of invasion-promoting genes in colorectal cancer cells, including the matrix-degrading urokinase-type plasminogen activator (uPA). Conversely, gelsolin knockdown reduces uPA levels, as well as uPA secretion. The enhanced invasiveness of gelsolin-overexpressing cells was attenuated by treatment with function-blocking antibodies to either uPA or its receptor uPAR, indicating that uPA/uPAR activity is crucial for gelsolin-dependent invasion. In summary, our data reveals novel functions of gelsolin in colorectal tumor cell invasion through its modulation of the uPA/uPAR cascade, with potentially important roles in colorectal tumor dissemination to metastatic sites

    The impact of working capital management on manufacturing firms' profitability - an emerging market perspective

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    Purpose: This study aims to investigate the effects of working capital management on firm profitability of listed manufacturing companies in Malaysia. Design/methodology/approach: This study uses account payables, inventory turnover, account receivables, cash conversion cycle, firm size, growth, leverage and current ratio as accounting information variables. Secondary data was collected for all variables over a ten-year period, i.e. 2009 to 2018 and was obtained from the annual report published via Bursa Malaysia (Malaysian Stock Exchange) official website. Data was analyzed by using IBM SPSS Statistics Subscription software. Descriptive statistics, correlation analysis and multiple regression analysis were utilized in this study. Findings: The results revealed that inventory turnover in days, account receivables and firm size have a positive significant relationship with manufacturing firms’ profitability, while account payables and cash conversion cycle have a positive insignificant relationship. Research limitations/implications: The sample size is too small for any generalization. A mixed method approach in the future could contribute to a holistic finding. Practical implications: Since these variables contained significant influence on firm profitability, it is recommended that listed manufacturing companies should prepare a complete and timely manner of accounting information based on the regulation context in Malaysia. Social implications: It provides an empirical evidence on the importance of working capital management amongst the manufacturing concerns in Malaysia and its impact on its business sustainability. Originality/value: This study contributes to the limited research on working capital management involving manufacturing companies in Malaysia

    Over-expression of severe acute respiratory syndrome coronavirus 3b protein induces both apoptosis and necrosis in Vero E6 cells

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    The genome of the severe acute respiratory syndrome coronavirus encodes for eight accessory viral proteins with no known homologues in other coronaviruses. One of these is the 3b protein, which is encoded by the second open reading frame in subgenomic RNA 3 and contains 154 amino acids. Here, a detailed time-course study was performed to compare the apoptosis and necrosis profiles induced by full-length 3b, a 3b mutant that was deleted by 30 amino acids from the C terminus (3b 124-154) and the classical apoptosis inducer, Bax. Our results showed that Vero E6 cells transfected with a construct for expressing 3b underwent necrosis as early as 6 h after transfection and underwent simultaneous necrosis and apoptosis at later time-points. At all the time-points analysed, the apoptosis induced by the expression of 3b was less than the level induced by Bax but the level of necrosis was comparable. The 3b 124-154 mutant behaves in a similar manner indicating that the localization of the 3b protein does not seems to be important for the cell-death pathways since full-length 3b is localized predominantly to the nucleolus, while the mutant is found to be concentrated in the peri-nuclear regions. To our knowledge, this is the first report of the induction of necrosis by a SARS-CoV protein.IS

    An Exploratory Study on Corporate Governance From Neuro-Governance Lenses in the Malaysian Context

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    Our minds are powerful, creative, forceful, and strong, controlling our thinking and behaviors. A series of high-profile accounting and financial scandals have been revealed in the past few decades, and the Enron case was the most representative of them all. Corporate decision-makers have traditionally enjoyed high remunerations, compensations, and social status. Hence, the underlying rationales and motivation drivers that motivate managers to conduct unethical behaviors have always been a heightened concern. This research aims to delineate the narratives of corporate governance misconducts and the underlying rationales of these unethical behaviors. This study incorporates independent variables of neuro-accounting, neuroeconomics, neuro-ethics, and human nature using a qualitative methodology. From this study, the social norm of fairness showed that the human nature of greed and selfishness would motivate corporate decision-makers to engage in any exchange that could benefit themselves, although it is unethical and illegal. Second, neuroeconomics revealed that scarcity of economic resources, level of risks and uncertainties, and expected rewards could be the factors that motivate managers to conduct unethical behaviors, especially when their remunerations are tightly linked to company performances. Third, neuroethics shows that managers who lack moral values, have unstable emotions, and possess negative moral intuitions or personal assumptions could be more likely to pursue their interests at the cost of others. Lastly, neuro-governance also proved that self-benefits and financial incentives will usually be the priority and would be a motivating factor for misconduct
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