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1.
The Snowden affair gave rise to a huge public debate about not only the legitimacy of the secret surveillance programs he revealed but also about Snowden himself and about the accuracy of the information he leaked. In this paper we present an analysis of how the affair was discussed in the English language blogosphere, based on a corpus of 15,000 blog posts written about Snowden and published from June 2013 to June 2014, as a sub-corpus of a larger corpus of 100,000 blog posts on the topic of surveillance, written during the period 2006–2014. Automated tools are used to identify the topics that characterize the blogging about surveillance and the posts about the Snowden affair. Through an in-depth analysis of the blog posts that commented on Snowden’s revelations of the PRISM program for surveillance of social media users, we chart how bloggers responded to Snowden and his role in this disclosure, whether they found the information credible, and the extent to which they expressed criticism of the surveillance practices. The analysis is used as a basis for discussing the role of blogs in the civic engagement during the first phase of the Snowden affair.  相似文献   
2.
Frost resistance is one of the most frequent characteristics of concrete. It is a very complex subject and the test methods themselves are still in development and the international consensus on methodology is still sought, too. The determination concrete frost resistance takes several weeks, months or even more than a year. However micro-structural changes as micro-cracks have not been described sufficiently. Acoustic Emission Method as unusual Non-Destructive Methods can help to monitor structural changes during common frost resistance measuring. Note the Acoustic Emission Method detects only active “defects” into monitored structure. Thus when e.g. crack grows some acoustic waves spread from crack place, i. e. from acoustic emission source. The method does not detect geometric discontinuities and “passive” defects. Selected Non-Destructive Methods as Ultrasound, Non-Linear Ultrasonic Spectroscopy, Impact Echo etc. are used to confirm micro-structural changes. The article describes the first experiment with its imperfections, difficulties and possibilities.  相似文献   
3.
A new concept of the measurement of the height of microdischarge pulses is proposed and implemented on a special hardware assembly. The concept utilizes the highly asymmetric shape of microdischarge pulses, i.e. the sharp rise edge and slowly decaying tail that forms an almost `horizontal' plateau. The maximum height of a pulse can be determined by imposing a certain time delay in saving sample points. The time delay must be equal to or longer than the time necessary for the full rise of the front edge of the pulse. The new concept completely removes time-consuming procedures seeking for signal local maxima used in current digitizers with logic circuits. This makes the system very fast and brings it to the very limit of the underlying natural process itself which represents the main advantage compared with other existing methods. A certain disadvantage of the new concept is in its restriction to asymmetric pulses only, but, however, this class of pulses comprises the broad spectrum of pulsating phenomena appearing in various branches of science and technology. This gives the proposed concept good applicability not only in the field of electric microdischarges but also in many other experimental domains  相似文献   
4.
Quantum Monte Carlo (QMC) applications perform simulation with respect to an initial state of the quantum mechanical system, which is often captured by using a cubic B‐spline basis. This representation is stored as a read‐only table of coefficients and accesses to the table are generated at random as part of the Monte Carlo simulation. Current QMC applications, such as QWalk and QMCPACK, replicate this table at every process or node, which limits scalability because increasing the number of processors does not enable larger systems to be run. We present a partitioned global address space approach to transparently managing this data using Global Arrays in a manner that allows the memory of multiple nodes to be aggregated. We develop an automated data management system that significantly reduces communication overheads, enabling new capabilities for QMC codes. Experimental results with QWalk and QMCPACK demonstrate the effectiveness of the data management system. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   
5.
Mesenchymal stem cells (MSCs) represent an attractive source within the field of tissue engineering. However, their harvesting often requires invasive medical procedures. Urine-derived stem cells (UDSCs) display similar properties to MSCs, and their obtention and further processing is non-invasive for the donors as well as low cost. Here, we offer a comprehensive analysis of their biological properties. The goal of this study was to analyze their morphology, stemness, differentiation potential and cytokine profile. We have successfully isolated UDSCs from 25 urine samples. First colonies emerged up to 9 days after the initial seeding. Cell doubling time was 45 ± 0.24 SD, and when seeded at the density of 100 cells/cm2, they formed 42 ± 6.5 SD colonies within 10 days. Morphological analyzes revealed that two different types of the cell populations have been present. The first type had a rice-grain shape and the second one was characterized by a polyhedral shape. In several cell cultures, dome-shaped cells were observed as well. All examined UDSCs expressed typical MSC-like surface markers, CD73, CD90 and CD105. Moreover, conditioned media from UDSCs were harvested, and cytokine profile has been evaluated showing a significantly higher secretory rate of IL-8, IL-6 and chemokines MCP-1 and GM-CSF. We have also successfully induced human UDSCs into chondrogenic, osteogenic and myogenic cell lineages. Our findings indicate that UDSCs might have immense potential in the regeneration of the damaged tissues.  相似文献   
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7.
Background: Tenascin-C (TN-C) plays a maladaptive role in left ventricular (LV) hypertrophy following pressure overload. However, the role of TN-C in LV regression following mechanical unloading is unknown. Methods: LV hypertrophy was induced by transverse aortic constriction for 10 weeks followed by debanding for 2 weeks in wild type (Wt) and TN-C knockout (TN-C KO) mice. Cardiac function was assessed by serial magnetic resonance imaging. The expression of fibrotic markers and drivers (angiotensin-converting enzyme-1, ACE-1) was determined in LV tissue as well as human cardiac fibroblasts (HCFs) after TN-C treatment. Results: Chronic pressure overload resulted in a significant decline in cardiac function associated with LV dilation as well as upregulation of TN-C, collagen 1 (Col 1), and ACE-1 in Wt as compared to TN-C KO mice. Reverse remodeling in Wt mice partially improved cardiac function and fibrotic marker expression; however, TN-C protein expression remained unchanged. In HCF, TN-C strongly induced the upregulation of ACE 1 and Col 1. Conclusions: Pressure overload, when lasting long enough to induce HF, has less potential for reverse remodeling in mice. This may be due to significant upregulation of TN-C expression, which stimulates ACE 1, Col 1, and alpha-smooth muscle actin (α-SMA) upregulation in fibroblasts. Consequently, addressing TN-C in LV hypertrophy might open a new window for future therapeutics.  相似文献   
8.
Eco-friendly mixtures may substitute pure working fluids in thermodynamic cycle processes, yet the existing calculation approaches of mixture condensation are complex due to iterative procedures and multiple input data. To simplify condenser design, this project aims for a new calculation method of mixtures. On this behalf, experimental data for the condensation of ethanol/water and ethanol/octamethyltrisiloxane is provided within a wide composition range to identify the most influential parameters. Finally, a practical prediction method for heat transfer coefficients of mixtures is suggested.  相似文献   
9.
Programmed cell death plays an essential role in the normal embryonic development of Drosophila melanogaster. One region of the embryo where cell death occurs, but has not been studied in detail, is the abdominal epidermis. Because cell death is a fleeting process, we have used time-lapse, fluorescence microscopy to map epidermal apoptosis throughout embryonic development. Cell death occurs in a stereotypically striped pattern near both sides of the segment border and to a lesser extent in the middle of the segment. This map of wild-type cell death was used to determine how cell death patterns change in response to genetic perturbations that affect epidermal patterning. Previous studies have suggested that segment polarity mutant phenotypes are partially the result of increased cell death. Mutations in wingless, armadillo, and gooseberry led to dramatic increases in apoptosis in the anterior of the segment while a naked mutation resulted in a dramatic increase in the death of engrailed cells in the posterior of the segment. These results show that segment polarity gene expression is necessary for the survival of specific rows of epidermal cells and may provide insight into the establishment of the wild-type epidermal cell death pattern.  相似文献   
10.
We provide a brief review of recent applications of quantum Monte Carlo (QMC) methods to the electronic structure of nanosystems. We report on calculations of carbon rings with second-order Jahn-Teller effect, energy ordering of silicon clusters, dissociation enthalpies of protonated hydrogen clusters, and other interesting challenges. We point out the QMC accuracy and outline a few ideas that characterize the current position of QMC among the electronic structure methods and its future development.  相似文献   
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