4,898 research outputs found

    An Empirical Study of Civil Servants’ Lifelong E-Learning Continuance Intention

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    E-learning is an effective way for job-training and continuous education. In recognizing the need for civil servants to embrace the lifelong learning to sustain competitiveness, many countries around the world have created policies to develop e-learning. This study is focus on civil servants’ e-learning continuance intention and through e-learning experience to achieve lifelong learning. Based on Information system (IS) success model proposed by Seddon (1997) and adding organizational factors (Incentive, Supervisor Support, and Technical Support) to survey civil servants’ e-learning behaviour. The sample for the study was taken from the civil servants in Taiwan who have the experience of using the lifelong e-learning websites. The results also support Seddon’s IS success model. Finally, the implications and limitations of the study are discussed

    A Study on the Satisfaction of Supply Chain Management System from the View of Justice and Value

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    Due to the common, most enterprises have utilized information technology (IT) to enhance their competition and performance. Meanwhile, governments in Taiwan have encouraged enterprises to adapt e-commerce by putting policies and facilitating technology. Nevertheless, only few literatures discuss or evaluate the satisfaction of E-SCM after establishing information systems by enterprises. This research attempts to integrate three well-founded theories – Information System Success model (ISS), Organization Justice Theory and Consumer Value to develop our model. Using Structural Square Modeling (SEM) analysis performed on results of a questionnaire given to the providers of SCM who have established the E-SCM in their enterprises. The results showed that the distributive justice, procedural justice and interactive justice in the organization justice theory have a significant effect on the performance outcome in the E-SCM. It also showed that the system and service quality in the IS success model and the cost and service value in shopping value have a significant effect on the satisfaction of the E-SCM. The contribution of this study can be further research in academic and practical

    C2H N=1-0 and N2H+ J=1-0 observations of Planck Galactic cold clumps

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    A survey of C2H N=1-0 and N2H+ J=1-0 toward Planck Galactic cold clumps (PGCCs) was performed using the Purple Mountain Observatory's 13.7 m telescope. C2H and N2H+ were chosen to study the chemical evolutionary states of PGCCs. Among 121 observed molecular cores associated with PGCCs, 71 and 58 are detected with C2H N=1-0 and N2H+ J=1-0, respectively. The detected lines of most sources can be fitted with a single component with compatible Vlsr and line widths, which confirms that these PGCC cores are very cold (with gas temperatures 9-21 K) and quiescent while still dominanted by turbulence. The ratio between the column densities of C2H and N2H+ (N(C2H)/N(N2H+)) is found to be a good tracer for the evolutionary states of PGCC cores. Gas-grain chemical model can reproduce the decreasing trend of N(C2H)/N(N2H+) as a function of time. The cores with the lowest abundances of N2H+ (X[N2H+] < 10^{-10}) are the youngest, and have nearly constant abundances of C2H. In evolved cores with X[N2H+] ~ 1E-9, abundances of C2H drop quickly as the exhaustion of carbon atoms. Although these PGCC cores are in different evolutionary states, they are all quite young ( N(N2H+). Mapping observations are carried out toward 20 PGCC cores. The PGCC cores in Cepheus have lower N(C2H)/N(N2H+) and larger line widths compared with those in Taurus. This implies that PGCC cores in Taurus are less chemically evolved than those in Cepheus.Comment: 23 pages, 6 figures, 5 table

    Optimizing mixture properties of biodiesel production using genetic algorithm-based evolutionary support vector machine

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    Nowadays, biodiesel is used as one of the alternative renewable energy due to the increasing energy demand. However, optimum production of biodiesel still requires a huge number of expensive and time-consuming laboratory tests. To address the problem, this research develops a novel Genetic Algorithm-based Evolutionary Support Vector Machine (GA-ESIM). The GA-ESIM is an Artificial Intelligence (AI)-based tool that combines K-means Chaotic Genetic Algorithm (KCGA) and Evolutionary Support Vector Machine Inference Model (ESIM). The ESIM is utilized as a supervised learning technique to establish a highly accurate prediction model between the input--output of biodiesel mixture properties; and the KCGA is used to perform the simulation to obtain the optimum mixture properties based on the prediction model. A real biodiesel experimental data is provided to validate the GA-ESIM performance. Our simulation results demonstrate that the GA-ESIM establishes a prediction model with better accuracy than other AI-based tool and thus obtains the mixture properties with the biodiesel yield of 99.9%, higher than the best experimental data record, 97.4%

    Signs of outflow feedback from a nearby young stellar object on the protostellar envelope around HL Tau

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    HL Tau is a Class I-II protostar embedded in an infalling and rotating envelope and possibly associated with a planet forming disk, and it is co-located in a 0.1 pc molecular cloud with two nearby young stellar objects. Our ALMA observations revealed two arc-like structures on a 1000 au scale connected to the disk, and their kinematics could not be explained with any conventional model of infalling and rotational motions. In this work, we investigate the nature of these arc-like structures connected to the HL Tau disk. We conducted new observations in the 13CO and C18O (3-2; 2-1) lines with JCMT and IRAM 30m, and obtained the ACA data with the 7-m array. With the single-dish, ACA, and ALMA data, we analyzed the gas motions on both 0.1 pc and 1000 au scales in the HL Tau region. We constructed new kinematical models of an infalling and rotating envelope with the consideration of relative motion between HL Tau and the envelope. By including the relative motion between HL Tau and its protostellar envelope, our kinematical model can explain the observed velocity features in the arc-like structures. The morphologies of the arc-like structures can also be explained with an asymmetric initial density distribution in our model envelope. In addition, our single-dish results support that HL Tau is located at the edge of a large-scale (0.1 pc) expanding shell driven by the wind or outflow from XZ Tau, as suggested in the literature. The estimated expanding velocity of the shell is comparable to the relative velocity between HL Tau and its envelope in our kinematical model. These results hints that the large-scale expanding motion likely impacts the protostellar envelope around HL Tau and affects its gas kinematics. We found that the mass infalling rate from the envelope onto the HL Tau disk can be decreased by a factor of two due to this impact by the large-scale expanding shell.Comment: Accepted by A&

    Density alteration in non-physiological cells

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    In the present study an important phenomenon of cells was discovered: the change of intracellular density in cell&#x27;s response to drug and environmental factors. For convenience, this phenomenon is named as &#x22;density alteration in non-physiological cells&#x22; ( DANCE). DANCE was determined by discontinuous sucrose gradient centrifugation (DSGC), in which cells were separated into several bands. The number and position of the bands in DSGC varied with the change of cell culture conditions, drugs, and physical process, indicating that cell&#x27;s response to these factors was associated with alteration of intracellular density. Our results showed that the bands of cells were molecularly different from each other, such as the expression of some mRNAs. For most cells tested, intracellular density usually decreased when the cells were in bad conditions, in presence of drugs, or undergoing pathological changes. However, unlike other tissue cells, brain cells showed increased intracellular density in 24 hrs after the animal death. In addition, DANCE was found to be related to drug resistance, with higher drug-resistance in cells of lower intracellular density. Further study found that DANCE also occurred in microorganisms including bacteria and fungus, suggesting that DANCE might be a sensitive and general response of cells to drugs and environmental change. The mechanisms for DANCE are not clear. Based on our study the following causes were hypothesized: change of metabolism mode, change of cell membrane function, and pathological change. DANCE could be important in medical and biological sciences. Study of DANCE might be helpful to the understanding of drug resistance, development of new drugs, separation of new subtypes from a cell population, forensic analysis, and importantly, discovery of new physiological or pathological properties of cells

    HII region G46.5-0.2: the interplay between ionizing radiation, molecular gas and star formation

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    HII regions are particularly interesting because they can generate dense layers of gas and dust, elongated columns or pillars of gas pointing towards the ionizing sources, and cometary globules of dense gas, where triggered star formation can occur. Understanding the interplay between the ionizing radiation and the dense surrounding gas is very important to explain the origin of these peculiar structures, and hence to characterize triggered star formation. G46.5-0.2 (G46), a poorly studied galactic HII region located at about 4 kpc, is an excellent target to perform this kind of studies. Using public molecular data extracted from the Galactic Ring Survey (13CO J=1-0) and from the James Clerk Maxwell Telescope data archive (12CO, 13CO, C18O J=3-2, HCO+ and HCN J=4-3), and infrared data from the GLIMPSE and MIPSGAL surveys, we perform a complete study of G46, its molecular environment and the young stellar objects placed around it. We found that G46, probably excited by an O7V star, is located close to the edge of the GRSMC G046.34-00.21 molecular cloud. It presents a horse-shoe morphology opening in direction of the cloud. We observed a filamentary structure in the molecular gas likely related to G46 and not considerable molecular emission towards its open border. We found that about 10' towards the southwest of G46 there are some pillar-like features, shining at 8 um and pointing towards the HII region open border. We propose that the pillar-like features were carved and sculpted by the ionizing flux from G46. We found several young stellar objects likely embedded in the molecular cloud grouped in two main concentrations: one, closer to the G46 open border consisting of Class II type sources, and other one mostly composed by Class I type YSOs located just ahead the pillars-like features, strongly suggesting an age gradient in the YSOs distribution.Comment: Accepted for publication in The Astronomical Journal (April 14, 2015). Some figures were degraded to reduce file siz
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