2,189 research outputs found

    LABOR MARKET BEHAVIOR IN WASHINGTON: A COINTEGRATION APPROACH

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    In recent years, the research that investigates impact of employment on other labor related variables has a prominent place in regional science. Generally, it is well understood that new business investment brings changes in population, increased labor force participation rate and migration of new residents. There is mixed research results regarding the extent that new migrants tend to account for new employment. Bartik (1993) found that about one-quarter of the new jobs go to local workers because of the increase in the labor force participation rates of local residents in the long run. He considered the long run effects by estimating the effects of 1% job growth in a certain period on the labor force participation rate seventeen years after the period. In contrast Blanchard and Katz's (1992) research reaches the opposite conclusion - in five to seven years the employment response consists entirely of the migration of new migrants. Their finding is that long-run effect of the job growth on the labor force participation rate is negligible. In this study, from the cointegration time series analysis, we found a long run equilibrium relationship among population, labor force participation rate and employment, in which population is positively related to employment and negatively related to labor force participation rate. The long run effect of a unit change of labor force participation rate (1%) is a decrease of 73,880 in population and the long run effect of a unit change in employment (1000) is an increase of 2,190 in population. We decomposed the time series into stationary components and non-stationary components. The pattern of the stationary component of population is quite similar to that of labor force participation rate while that of employment shows a different fluctuation. From the decomposition, it was obvious that the pattern of stationary component of employment and net migration is quite similar, which means net migration is the short run, temporary response to employment change. The patterns of three years delayed stationary components of population are similar to that of employment and net migration, and the plots correspond to changing economic conditions. According to the change in economic conditions population responds three years later than employment and net migration. We interpreted the non-stationary component of labor force participation rate as reflecting the increasing trend of labor force participation rate in Washington mainly due to a considerable increase in the female labor force participation. The impulse responses of population, employment and labor force participation rate to a one standard deviation shock in employment show permanent increase effects. They settle at different equilibrium value after long term periods. The response of the labor force participation rate to an impulse in employment supports Bartik's finding. Obviously the result is the opposite of Blanchard-Katz's finding that the long-run effect of job growth on the labor force participation rate is negligible. However, since the effect of population is also significantly high, we doubt that the effect of increase in labor force participation rate according to the employment shock covers only local resident labor force.Labor and Human Capital,

    User survey regarding the needs of network researchers in trace-anonymization tools

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    To understand the needs of network researchers in an anonymization tool, we conducted a survey on the network researchers. We invited network researchers world-wide to the survey by sending invitation emails to well-known mailing lists whose subscribers may be interested in network research with collecting, sharing and sanitizing network traces

    Ginseng (Panax quinquefolius) and Licorice (Glycyrrhiza uralensis) Root Extract Combinations Increase Hepatocarcinoma Cell (Hep-G2) Viability

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    The combined cytoactive effects of American ginseng (Panax quinquefolius) and licorice (Glycyrrhiza uralensis) root extracts were investigated in a hepatocarcinoma cell line (Hep-G2). An isobolographic analysis was utilized to express the possibility of synergistic, additive or antagonistic interaction between the two extracts. Both ginseng and licorice roots are widely utilized in traditional Chinese medicine preparations to treat a variety of ailments. However, the effect of the herbs in combination is currently unknown in cultured Hep-G2 cells. Ginseng (GE) and licorice (LE) extracts were both able to reduce cell viability. The LC50 values, after 72 h, were found to be 0.64 ± 0.02 mg/mL (GE) and 0.53 ± 0.02 mg/mL (LE). An isobologram was plotted, which included five theoretical LC50s calculated, based on the fixed fraction method of combination ginseng to licorice extracts to establish a line of additivity. All combinations of GE to LE (1/5, 1/3, 1/2, 2/3, 4/5) produced an effect on Hep-G2 cell viability but they were all found to be antagonistic. The LC50 of fractions 1/3, 1/2, 2/3 were 23%, 21% and 18% above the theoretical LC50. Lactate dehydrogenase release indicated that as the proportion of GE to LE increased beyond 50%, the influence on membrane permeability increased. Cell-cycle analysis showed a slight but significant arrest at the G1 phase of cell cycle for LE. Both GE and LE reduced Hep-G2 viability independently; however, the combinations of both extracts were found to have an antagonistic effect on cell viability and increased cultured Hep-G2 survival

    Tidal current turbine blade optimisation with improved blade element momentum theory and a non-dominated sorting genetic algorithm

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    Tidal current energy has the advantage of predictability over most of the other renewable energy resources. However, due to the harsh operating environment and complicated site conditions, developments in this domain have been gradual. Paramount to these points is device design and optimisation of hydrodynamic performance. Recent developments in the correction models of BEM theory have further improved the accuracy of the prediction model. Using an improved blade element momentum theory model that is capable of accurately capturing the downwash angle and combining it with a well-developed and reliable non-dominated sorting genetic algorithm model, an effective and efficient tidal current turbine blade optimisation tool has been developed and is presented in this paper. This novel work incorporated a NACA generator that is capable of reproducing any NACA profile, such a tool allows the solver to analyse each and every profile used in each spanwise blade element. As a result, the model is very effective at producing tidal current turbine blades that have been optimised not only for local twist angle and chord length, but also for the suitable NACA profiles to be used at a particular spanwise blade element. The use of the non-dominated sorting genetic algorithm in this work allows the model to efficiently explore a wide range of solutions, outputting a number of tidal current turbine blades suitable for a specified operating condition. The accuracy of the performance prediction of the improved BEM model is validated against an experimentally validated tidal current turbine blade. The coefficient of determination (R2) values for power and thrust coefficient are 0.99828 and 0.99488 respectively when comparing this work with experimental measurements found in the literature. Furthermore this proves that the improved BEM model is capable of efficiently predicting hydrodynamic performance of a tidal current turbine blade to a high degree of accuracy. Further work includes implementing computational fluid dynamics for further validation and evaluation

    A Correlation Attack Against User Mobility Privacy in a Large-scale WLAN network

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    User association logs collected from real-world wireless LANs have facilitated wireless network research greatly. To protect user privacy, the common practice in sanitizing these data before releasing them to the public is to anonymize users\u27 sensitive information such as the MAC addresses of their devices and their exact association locations. In this work,we demonstrate that these sanitization measures are insufficient in protecting user privacy from a novel type of correlation attack that is based on CRF (Conditional Random Field). In such a correlation attack, the adversary observes the victim\u27s AP (Access Point) association activities for a short period of time and then infers her corresponding identity in a released user association dataset. Using a user association log that contains more than three thousand users and millions of AP association records, we demonstrate that the CRF-based technique is able to pinpoint the victim\u27s identity exactly with a probability as high as 70%

    Catch, Clean, and Release: A Survey of Obstacles and Opportunities for Network Trace Sanitization

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    Network researchers benefit tremendously from access to traces of production networks, and several repositories of such network traces exist. By their very nature, these traces capture sensitive business and personal activity. Furthermore, network traces contain significant operational information about the target network, such as its structure, identity of the network provider, or addresses of important servers. To protect private or proprietary information, researchers must “sanitize” a trace before sharing it. \par In this chapter, we survey the growing body of research that addresses the risks, methods, and evaluation of network trace sanitization. Research on the risks of network trace sanitization attempts to extract information from published network traces, while research on sanitization methods investigates approaches that may protect against such attacks. Although researchers have recently proposed both quantitative and qualitative methods to evaluate the effectiveness of sanitization methods, such work has several shortcomings, some of which we highlight in a discussion of open problems. Sanitizing a network trace, however challenging, remains an important method for advancing network–based research

    Ginseng (Panax quinquefolius) Reduces Cell Growth, Lipid Acquisition and Increases Adiponectin Expression in 3T3-L1 Cells

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    An American ginseng (Panax quinquefolius) extract (GE) that contained a quantifiable amount of ginsenosides was investigated for the potential to inhibit proliferation, affect the cell cycle, influence lipid acquisition and adiponectin expression in 3T3-L1 cells. Six fingerprint ginsenosides were quantified by high performance liquid chromatography and the respective molecular weights were confirmed by LC-ESI-MS analysis. The extract contained Rg1 (347.3 ± 99.7 μg g−1, dry weight), Re (8280.4 ± 792.3 μg g−1), Rb1 (1585.8 ± 86.8 μg g−1), Rc (32.9 ± 8 μg g−1), Rb2 (62.6 ± 10.6 μg g−1) and Rd (90.4 ± 3.2 μg g−1). The GE had a dose-dependent effect on 3T3-L1 cell growth, the LC50 value was determined to be 40.3 ± 5 μg ml−1. Cell cycle analysis showed modest changes in the cell cycle. No significant changes observed in both G1 and G2/M phases, however there was a significant decrease (P < .05) in the S phase after 24 and 48 h treatment. Apoptotic cells were modest but significantly (P < .05) increased after 48 h (3.2 ± 1.0%) compared to untreated control cells (1.5 ± 0.1%). Lipid acquisition was significantly reduced (P < .05) by 13 and 22% when treated at concentrations of 20.2 and 40.3 μg ml−1 compared to untreated control cells. In relation to adiponectin activation, western blot analysis showed that the protein expression was significantly (P < .05) increased at concentrations tested. A quantified GE reduced the growth of 3T3-L1 cells, down-regulated the accumulation of lipid and up-regulated the expression of adiponectin in the 3T3-L1 adipocyte cell model
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