1,075 research outputs found

    Planning work crew assignments for pedestrian area renovation to improve its impact on the public

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    When renovating a pedestrian area, it is crucial to maintain as normal as possible an operation while the renovation activities are underway. Usually the area is divided into several zones to accommodate the renovation in sections. A zone closure forces the users to take an alternative route that could be longer or more congested. The impact of such rerouting must be minimized by properly planning the work crews. In this paper, the author proposed a model using simulation to estimate the impact of the extra walking distance on pedestrians, and ant colony optimization to search for the nearoptimal work crew schedule. The author applied the model to the renovation of a public pedestrian area in a villa resort. It provides a near-optimal work schedule for a variety of work crews with minimal walking time delay for the pedestrians. This model takes into account total walking time delay, average delay per person, and total duration in order to evaluate all alternatives to allow both owner and contractor to decide the appropriate work schedule

    How can value co-creation be integrated into a customer experience evaluation?

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    With the arrival of the service economy, businesses across different sectors have to rely increasingly on service design, with its focus on the viewpoints of customers and their experiences. Existing frameworks for evaluating customer experience tend to neglect the connection between customer experience and value co-creation, which is critical for enhancing the performance of service design. The aim of this conceptual paper is, therefore, to develop a customer experience evaluation framework that is coherently integrated with the value co-creation construct. It is achieved by intersecting the most relevant insights from prior approaches to evaluating customer experiences with a theoretical interpretation of service value as value in the experience that is always co-created and uniquely determined by the customer's personal lived and imagined experiences. The proposed framework is original in its theorizing of the evaluation process as a transformation from a customer experience evaluation to a synchronized evaluation of value in the experience and value co-creation throughout and beyond the service process. The framework proposes to utilize it in both major service redesign and on-the-spot service improvements, which are extremely relevant to businesses operating in highly competitive environments. The proposed framework is designed to guide future empirical evaluations, accommodate new theoretical extensions, and inform practical applications to design service offerings as unique and preferred experiences for customers

    Increased Risk for Entamoeba histolytica Infection and Invasive Amebiasis in HIV Seropositive Men Who Have Sex with Men in Taiwan

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    Entamoeba histolytica, morphologically identical to but genetically different from E. dispar and E. moshkovskii, is the causative agent of amebiasis. Recently there have been reports of increased risk for amebiasis among men who have sex with men (MSM) due to oral-anal sexual contact in several developed countries. In this longitudinal follow-up study, the incidence of amebiasis was determined among HIV-infected patients using serological and specific amebic antigen assays. DNA extracted from stool samples containing E. histolytica were analyzed by PCR, sequenced, and compared. Clinical manifestations and treatment response of invasive amebiasis in HIV-infected patients were reviewed. The results demonstrated that HIV-infected MSM were at significantly higher risk of amebiasis than patients from other risk groups. Clustering of E. histolytica isolates by sequencing analyses from geographically unrelated patients suggested person-to-person transmission. Despite immunosuppression, amebic liver abscesses and colitis responded favorably to metronidazole therapy. It is important to investigate in areas of high incidence of both amebiasis and HIV (sub-Saharan Africa) how generalizable these findings are

    Technology Anxiety and Implicit Learning Ability Affect Technology Leadership to Promote the use of Information Technology at Elementary Schools

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    Abstract“Oversold & underused” is a criticism by Cuban (2001) of the investment of information technology (IT) in the classroom. Recently, Taiwan's educational administration has provided considerable financial support to IT in elementary schools, but few reports have provided evidence of its successful use. The present study aims to identify the personal factors that affect principals’ beliefs about the promotion of IT in their schools. 331 data were collected and analyzed with AMOS 19.0. The results of this study indicated that greater technology anxiety was negatively associated with perceived ease of using (PEU) IT, whereas implicit learning ability was positively correlated with perceived usefulness of IT. Technology leadership increased significantly with PEU and perceived usefulness (PU), it is also associated with the intention to overcome difficulties in promoting information technology in schools. The implications of this study may contribute to the reduction of principals’ technology anxiety, increasing their implicit learning ability and therefore fostering the future implementation of IT in schools, changing the myth of technology as “oversold & underused”

    The genome sequence of Salmonella enterica serovar Choleraesuis, a highly invasive and resistant zoonotic pathogen

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    Salmonella enterica serovar Choleraesuis (S.Choleraesuis), a highly invasive serovar among non-typhoidal Salmonella, usually causes sepsis or extra-intestinal focal infections in humans. S.Choleraesuis infections have now become particularly difficult to treat because of the emergence of resistance to multiple antimicrobial agents. The 4.7 Mb genome sequence of a multidrug-resistant S.Choleraesuis strain SC-B67 was determined. Genome wide comparison of three sequenced Salmonella genomes revealed that more deletion events occurred in S.Choleraesuis SC-B67 and S.Typhi CT18 relative to S.Typhimurium LT2. S.Choleraesuis has 151 pseudogenes, which, among the three Salmonella genomes, include the highest percentage of pseudogenes arising from the genes involved in bacterial chemotaxis signal-transduction pathways. Mutations in these genes may increase smooth swimming of the bacteria, potentially allowing more effective interactions with and invasion of host cells to occur. A key regulatory gene of TetR/AcrR family, acrR, was inactivated through the introduction of an internal stop codon resulting in overexpression of AcrAB that appears to be associated with ciprofloxacin resistance. While lateral gene transfer providing basic functions to allow niche expansion in the host and environment is maintained during the evolution of different serovars of Salmonella, genes providing little overall selective benefit may be lost rapidly. Our findings suggest that the formation of pseudogenes may provide a simple evolutionary pathway that complements gene acquisition to enhance virulence and antimicrobial resistance in S.Choleraesuis

    Mechanisms underlying Actinobacillus pleuropneumoniae exotoxin ApxI induced expression of IL-1β, IL-8 and TNF-α in porcine alveolar macrophages

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    Actinobacillus pleuropneumoniae (A. pleuropneumoniae) causes fibrino-hemorrhagic necrotizing pleuropneumonia in pigs. Production of proinflammatory mediators in the lungs is an important feature of A. pleuropneumoniae infection. However, bacterial components other than lipopolysaccharide involved in this process remain unidentified. The goals of this study were to determine the role of A. pleuropneumoniae exotoxin ApxI in cytokine induction and to delineate the underlying mechanisms. Using real-time quantitative PCR analysis, we found native ApxI stimulated porcine alveolar macrophages (PAMs) to transcribe mRNAs of IL-1β, IL-8 and TNF-α in a concentration- and time-dependent manner. Heat-inactivation or pre-incubation of ApxI with a neutralizing antiserum attenuated ApxI bioactivity to induce cytokine gene expression. The secretion of IL-1β, IL-8 and TNF-α protein from PAMs stimulated with ApxI was also confirmed by quantitative ELISA. In delineating the underlying signaling pathways contributing to cytokine expression, we observed mitogen-activated protein kinases (MAPKs) p38 and cJun NH2-terminal kinase (JNK) were activated upon ApxI stimulation. Administration of an inhibitor specific to p38 or JNK resulted in varying degrees of attenuation on ApxI-induced cytokine expression, suggesting the differential regulatory roles of p38 and JNK in IL-1β, IL-8 and TNF-α production. Further, pre-incubation of PAMs with a CD18-blocking antibody prior to ApxI stimulation significantly reduced the activation of p38 and JNK, and subsequent expression of IL-1β, IL-8 or TNF-α gene, indicating a pivotal role of β2 integrins in the ApxI-mediated effect. Collectively, this study demonstrated ApxI induces gene expression of IL-1β, IL-8 and TNF-α in PAMs that involves β2 integrins and downstream MAPKs

    Cosmology and Accelerator Tests of Strongly Interacting Dark Matter

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    A natural possibility for dark matter is that it is composed of the stable pions of a QCD-like hidden sector. Existing literature largely assumes that pion self-interactions alone control the early universe cosmology. We point out that processes involving vector mesons typically dominate the physics of dark matter freeze-out and significantly widen the viable mass range for these models. The vector mesons also give rise to striking signals at accelerators. For example, in most of the cosmologically favored parameter space, the vector mesons are naturally long-lived and produce Standard Model particles in their decays. Electron and proton beam fixed-target experiments such as HPS, SeaQuest, and LDMX can exploit these signals to explore much of the viable parameter space. We also comment on dark matter decay inherent in a large class of previously considered models and explain how to ensure dark matter stability.Comment: 20 pages (4 in the Appendix), 6 figures; references adde

    All-trans retinoic acid ameliorates glycemic control in diabetic mice via modulating pancreatic islet production of vascular endothelial growth factor-A.

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    Patients with type 1 diabetes mellitus are associated with impairment in vitamin A metabolism. This study evaluated whether treatment with retinoic acid, the biologically active metabolite of vitamin A, can ameliorate diabetes. All-trans retinoic acid (atRA) was used to treat streptozotocin (STZ)-induced diabetic mice which revealed atRA administration ameliorated blood glucose levels of diabetic mice. This hyperglycemic amelioration was accompanied by an increase in the amount of β cells co-expressed Pdx1 and insulin and by restoration of the vascular laminin expression. The atRA-induced production of vascular endothelial growth factor-A from the pancreatic islets was possibly the key factor that mediated the restoration of islet vascularity and recovery of β-cell mass. Furthermore, the combination of islet transplantation and atRA administration significantly rescued hyperglycemia in diabetic mice. These findings suggest that vitamin A derivatives can potentially be used as a supplementary treatment to improve diabetes management and glycemic control

    Toxicity assessments of chalcone and some synthetic chalcone analogues in a zebrafish model

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    [[abstract]]The aim of this study was to investigate the in vivo toxicities of some novel synthetic chalcones. Chalcone and four chalcone analogues 1a–d were evaluated using zebrafish embryos following antibody staining to visualize their morphological changes and muscle fiber alignment. Results showed that embryos treated with 3'-hydroxychalcone (compound 1b) displayed a high percentage of muscle defects (96.6%), especially myofibril misalignment. Ultrastructural analysis revealed that compound 1b-treated embryos displayed many muscle defect phenotypes, including breakage and collapse of myofibrils, reduced cell numbers, and disorganized thick (myosin) and thin (actin) filaments. Taken together, our results provide in vivo evidence of the myotoxic effects of the synthesized chalcone analogues on developing zebrafish embryos.[[incitationindex]]SCI[[booktype]]電子
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