76 research outputs found

    She? The Role of Perceived Agent Gender in Social Media Customer Service

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    This paper investigated the role of perceived agent gender in customer behavior using a unique dataset from Southwest Airlines\u27 Twitter account. We inferred agent gender based on the first names provided by agents when responding to customers. We measured customer behavior using three outcomes: whether a customer decided to continue the service conversation upon receiving an agent’s initial response as well as the valence and arousal levels in their second tweet if the customer chose to continue the interaction. Our identification strategy relied on the Backdoor Criterion and hinged on the assumption that customer service requests are assigned to the next available agent, independent of agent gender. The findings revealed that customers were more likely to continue interactions with female agents than male agents and they were more negative in valence but less intense in arousal with the former group than with the latter

    Connections Between Connexins, Calcium, and Cataracts in the Lens

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    There is a good deal of evidence that the lens generates an internal micro circulatory system, which brings metabolites, like glucose, and antioxidants, like ascorbate, into the lens along the extracellular spaces between cells. Calcium also ought to be carried into the lens by this system. If so, the only path for Ca2+ to get out of the lens is to move down its electrochemical gradient into fiber cells, and then move by electrodiffusion from cell to cell through gap junctions to surface cells, where Ca-ATPase activity and Na/Ca exchange can transport it back into the aqueous or vitreous humors. The purpose of the present study was to test this calcium circulation hypothesis by studying calcium homeostasis in connexin (Cx46) knockout and (Cx46 for Cx50) knockin mouse lenses, which have different degrees of gap junction coupling. To measure intracellular calcium, FURA2 was injected into fiber cells, and the gradient in calcium concentration from center to surface was mapped in each type of lens. In wild-type lenses the coupling conductance of the mature fibers was ∼0.5 S/cm2 of cell to cell contact, and the best fit to the calcium concentration data varied from 700 nM in the center to 300 nM at the surface. In the knockin lenses, the coupling conductance was ∼1.0 S/cm2 and calcium varied from ∼500 nM at the center to 300 nM at the surface. Thus, when the coupling conductance doubled, the concentration gradient halved, as predicted by the model. In knockout lenses, the coupling conductance was zero, hence the efflux path was knocked out and calcium accumulated to ∼2 μM in central fibers. Knockout lenses also had a dense central cataract that extended from the center to about half the radius. Others have previously shown that this cataract involves activation of a calcium-dependent protease, Lp82. We can now expand on this finding to provide a hypothesis on each step that leads to cataract formation: knockout of Cx46 causes loss of coupling of mature fiber cells; the efflux path for calcium is therefore blocked; calcium accumulates in the central cells; at concentrations above ∼1 μM (from the center to about half way out of a 3-wk-old lens) Lp82 is activated; Lp82 cleaves cytoplasmic proteins (crystallins) in central cells; and the cleaved proteins aggregate and scatter light

    A kernel-free L1 norm regularized ν-support vector machine model with application

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    With a view to overcoming a few shortcomings resulting from the kernel-based SVM models, these kernel-free support vector machine (SVM) models are newly promoted and researched. With the aim of deeply enhancing the classification accuracy of present kernel-free quadratic surface support vector machine (QSSVM) models while avoiding computational complexity, an emerging kernel-free ν-fuzzy reduced QSSVM with L1 norm regularization model is proposed. The model has well-developed sparsity to avoid computational complexity and overfitting and has been simplified as these standard linear models on condition that the data points are (nearly) linearly separable. Computational tests are implemented on several public benchmark datasets for the purpose of showing the better performance of the presented model compared with a few known binary classification models. Similarly, the numerical consequences support the more elevated training effectiveness of the presented model in comparison with those of other kernel-free SVM models. What`s more, the presented model is smoothly employed in lung cancer subtype diagnosis with good performance, by using the gene expression RNAseq-based lung cancer subtype (LUAD/LUSC) dataset in the TCGA database

    Lens intracellular hydrostatic pressure is generated by the circulation of sodium and modulated by gap junction coupling

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    We recently modeled fluid flow through gap junction channels coupling the pigmented and nonpigmented layers of the ciliary body. The model suggested the channels could transport the secretion of aqueous humor, but flow would be driven by hydrostatic pressure rather than osmosis. The pressure required to drive fluid through a single layer of gap junctions might be just a few mmHg and difficult to measure. In the lens, however, there is a circulation of Na+ that may be coupled to intracellular fluid flow. Based on this hypothesis, the fluid would cross hundreds of layers of gap junctions, and this might require a large hydrostatic gradient. Therefore, we measured hydrostatic pressure as a function of distance from the center of the lens using an intracellular microelectrode-based pressure-sensing system. In wild-type mouse lenses, intracellular pressure varied from ∼330 mmHg at the center to zero at the surface. We have several knockout/knock-in mouse models with differing levels of expression of gap junction channels coupling lens fiber cells. Intracellular hydrostatic pressure in lenses from these mouse models varied inversely with the number of channels. When the lens’ circulation of Na+ was either blocked or reduced, intracellular hydrostatic pressure in central fiber cells was either eliminated or reduced proportionally. These data are consistent with our hypotheses: fluid circulates through the lens; the intracellular leg of fluid circulation is through gap junction channels and is driven by hydrostatic pressure; and the fluid flow is generated by membrane transport of sodium

    Comprehensive Pan-Genomic Characterization of Adrenocortical Carcinoma

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    SummaryWe describe a comprehensive genomic characterization of adrenocortical carcinoma (ACC). Using this dataset, we expand the catalogue of known ACC driver genes to include PRKAR1A, RPL22, TERF2, CCNE1, and NF1. Genome wide DNA copy-number analysis revealed frequent occurrence of massive DNA loss followed by whole-genome doubling (WGD), which was associated with aggressive clinical course, suggesting WGD is a hallmark of disease progression. Corroborating this hypothesis were increased TERT expression, decreased telomere length, and activation of cell-cycle programs. Integrated subtype analysis identified three ACC subtypes with distinct clinical outcome and molecular alterations which could be captured by a 68-CpG probe DNA-methylation signature, proposing a strategy for clinical stratification of patients based on molecular markers

    Comprehensive Molecular Portraits of Invasive Lobular Breast Cancer

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    Invasive lobular carcinoma (ILC) is the second most prevalent histologic subtype of invasive breast cancer. Here, we comprehensively profiled 817 breast tumors, including 127 ILC, 490 ductal (IDC), and 88 mixed IDC/ILC. Besides E-cadherin loss, the best known ILC genetic hallmark, we identified mutations targeting PTEN, TBX3 and FOXA1 as ILC enriched features. PTEN loss associated with increased AKT phosphorylation, which was highest in ILC among all breast cancer subtypes. Spatially clustered FOXA1 mutations correlated with increased FOXA1 expression and activity. Conversely, GATA3 mutations and high expression characterized Luminal A IDC, suggesting differential modulation of ER activity in ILC and IDC. Proliferation and immune-related signatures determined three ILC transcriptional subtypes associated with survival differences. Mixed IDC/ILC cases were molecularly classified as ILC-like and IDC-like revealing no true hybrid features. This multidimensional molecular atlas sheds new light on the genetic bases of ILC and provides potential clinical options
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