448 resultados para OECT PEDPT:PSS Biosensoristica elettrochimica


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In order to analyze the test anxiety of Beijing's high school students, relevant factors affecting test anxiety and how those factors have effect on the test anxiety of those high school students, a cross-sectional study had been conducted among 2,089 students randomly selected from 15 high schools in Beijing, using the Test Anxiety Scale(TAS), Parenting Style Scale (PSS) and Academic Aggregate Graphic (AAG). Five months later, 194 students from one of those high schools were retested with TAS with students remaining anonymous. In the retest, the classes and birth dates of those students were strictly matched. This paper is composed of three parts to examine the issue. The first part examines the test anxiety among high school students in Beijing and establishes the model; the second part conducts a comparative study of issues related to test anxiety and academic performance; the third part examines the factors affecting test anxiety and establishes the model. Results showed that: 1. The reliability and validity of TAS are satisfied and can meet survey requirement. The 25-item version of TAS turned out to have equal or even better performance compared with the original 37-item version. 2. Incidence of test anxiety in high schools of Beijing: 57.9 percent of samples have an overall score at or higher 15. 55 percent of male student samples have a score at or higher than 15 while that for female student samples is 61 percent. A score of 20 refers to fairly serious test anxiety and 31.9 percent of samples have a score over 20. 28.1 percent of the male student samples have a score of over 20 while that for female student samples is 35.9 percent. 3. The effect of grade and sex and the interaction between the two factors are statistically significant. Female students have higher test anxiety than male students and the level of test anxiety varies from grade to grade. 4. Samples are divided into two groups, one with test anxiety and the other without. The academic performance gap between the two groups is very significant. There is a significant negative correlation between academic score and test anxiety. 5. There is a negative correlation between test anxiety and mastery goal orientation and a positive correlation between test anxiety and performance goal orientation. Students with higher academic self-efficiency have lower test anxiety. The more one thinks study is valuable, the lower his/her test anxiety is. Those whose parents communicate smoothly with them have lower test anxiety. Those whose parents have an inconsistent communication style have higher test anxiety. 6. Achievement goal is mediate variable for the effect of lack of values on test anxiety. 7. The indirect effect of introduction of achievement goal and parenting style, including communication, monitoring and communication consistence, on test anxiety is significant. Key words: Test anxiety,reliability, validity, self-efficiency,parenting style,achievement goal orientation, academic values, academic score

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Both perceived organizational support and job stresses have impact on employees’ work outcomes. Great progresses have been made in past researches. However, there are many disputes about the impact of perceived organizational support (POS) on job performance (especially, safety performance), the impact of job stresses on job performance (especially, safety performance) and job attitudes, as well as the interaction of subordinates’ POS and job stresses, and the impact of supervisor on subordinates’ POS et al.. Thus, the aim of the study is to explore the impact of supervisors’ POS, leader-member exchange(LMX) on subordinates’ POS, the direct impact of subordinates’ POS and job stressors from task and rewards on work attitudes(job satisfaction, turnover intention) and safety behaviors(safety compliance and safety participation), and the interaction of subordinates’ POS and job stresses. Analyses are based on the data from interviewing of 20 staff, posts of a Chinese civil aviation Bulletin Board System (BBS) and surveys of 216 subordinates and 42 supervisors from two Chinese civil aviation Air traffic control centers (ATC). The major findings are listed as follows: Firstly, the exchange relationship between supervisors and members has impact on subordinates’ POS by the fully mediating role of subordinates’ perceived supervisor support (PSS). But supervisors’ POS have no impact on subordinates’ POS. Secondly, subordinates’ POS has a direct and positive impact on their job satisfaction and safety behaviors, and a negative impact on turnover intention. Specifically, the higher the employees’ perceived organizational support, the higher job satisfaction and safety behaviors, as well as the lower turnover intention they have. Moreover, POS has stronger relationship with safety participation behaviors than that of safety compliance behaviors. Thirdly, task-related stressor has no significant impact on job satisfaction, turnover intention and safety behaviors. And compensation-related stressor has significant and positive impact on turnover intention and safety behaviors, which means that with the compensation-related stress increases, turnover intention increases, safety behaviors including safety compliance and safety participation also increases. Fourthly, POS and task-related stressor, POS and compensation-related stressor have significant interaction, respectively. Specifically, POS moderates the relationship between task-related stressor and job satisfaction, and between task-related stressor and turnover intention. Moreover, POS also moderates the relationship between compensation-related stressor and safety compliance behaviors.

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Grande, Manuel; Kellett, B.; Howe, C.; Perry, C.H., 'The D-CIXS X-ray spectrometer on the SMART-1 mission to the Moon - First Results', Planetary And Space Science (2007) 55(4) pp.494-502 RAE2008

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For efficient use of metal oxides, such as MnO(2) and RuO(2), in pseudocapacitors and other electrochemical applications, the poor conductivity of the metal oxide is a major problem. To tackle the problem, we have designed a ternary nanocomposite film composed of metal oxide (MnO(2)), carbon nanotube (CNT), and conducting polymer (CP). Each component in the MnO(2)/CNT/CP film provides unique and critical function to achieve optimized electrochemical properties. The electrochemical performance of the film is evaluated by cyclic voltammetry, and constant-current charge/discharge cycling techniques. Specific capacitance (SC) of the ternary composite electrode can reach 427 F/g. Even at high mass loading and high concentration of MnO(2) (60%), the film still showed SC value as high as 200 F/g. The electrode also exhibited excellent charge/discharge rate and good cycling stability, retaining over 99% of its initial charge after 1000 cycles. The results demonstrated that MnO(2) is effectively utilized with assistance of other components (fFWNTs and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) in the electrode. Such ternary composite is very promising for the next generation high performance electrochemical supercapacitors.

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The NOMAD spectrometer suite on the ExoMars Trace Gas Orbiter will map the composition and distribution of Mars atmospheric trace species in unprecedented detail, fulfilling many of the scientific objectives of the joint ESA-Roscosmos ExoMars Trace Gas Orbiter mission. The instrument is a combination of three channels, covering a spectral range from the UV to the IR, and can perform solar occultation, nadir and limb observations. In this paper, we present the science objectives of the instrument and how these objectives have influenced the design of the channels. We also discuss the expected performance of the instrument in terms of coverage and detection sensitivity.

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Western manufacturing companies are developing innovative ways of delivering value that competes with the low cost paradigm. One such strategy is to deliver not only products, but systems that are closely aligned with the customer value proposition. These systems are comprised of integrated products and services, and are referred to as Product-Service Systems (PSS). A key challenge in PSS is supporting the design activity. In one sense, PSS design is a further extension of concurrent engineering that requires front-end input from the additional downstream sources of product service and maintenance. However, simply developing products and service packages is not sufficient: the new design challenge is the integrated system. This paper describes the development of a PSS data structure that can support this integrated design activity. The data structure is implemented in a knowledge base using the Protégé knowledge base editor.

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The presenilins (PSs) were identified as causative genes in cases of early-onset familial Alzheimer's disease (AD) and current evidence indicates that PSs are part of the gamma-secretase complex responsible for proteolytic processing of type I membrane proteins. p75NTR, a common neurotrophin receptor, was shown to be subject to gamma-secretase processing. However, it is not clear if the p75NTR downstream signal is altered in response to gamma-secretase cleavage, and further there is a possibility that AD-related PS mutations may affect this cleavage, resulting in pathogenic alterations in signal transduction. In this study, we confirmed that p75NTR downstream signalling is altered by PS2 mutation or gamma-secretase inhibition in SHSY-5Y cells. The activity of the small GTPase RhoA is strongly affected by these treatments. This study demonstrates that gamma-secretase and PS2 play an important role in regulating neurotrophin signal transduction and either mutation of PS2 or inhibition of gamma-secretase disturbs this function.

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Photoresponse of n-type indium-doped ZnO and a p-type polymer (PEDOT:PSS) heterojunction devices are studied, juxtaposed with the photoluminescence of the In-ZnO samples. In addition to the expected photoresponse in the ultraviolet, the heterojunctions exhibit significant photoresponse to the visible (532 nm). However, neither the doped ZnO nor PEDOT: PSS individually show any photoresponse to visible light. The sub-bandgap photoresponse of the heterojunction originates from visible photon mediated e-h generation between the In-ZnO valence band and localized states lying within the band gap. Though increased doping of In-ZnO has limited effect on the photoluminescence, it significantly diminishes the photoresponse. The study indicates that optimally doped devices are promising for the detection of wavelengths in selected windows in the visible. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4704655]

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Bulk paleosol samples collected from a Middle to Early Miocene moraine in the New Mountain area of the Dry Valleys, Antarctica, yielded Coleoptera exoskeletons and occasional endoskeletons showing considerable diagenetic effects along with several species of bacteria, all lodged in a dry-frozen but salt-rich horizon at shallow depth to the land surface. The till is at the older end of a chronologic sequence of glacial deposits, thought to have been deposited before the transition from wet-based to cold-based ice (similar to 15 Ma), and hence, entirely weathered in contact with the subaerial atmosphere. It is possible, though not absolutely verifiable, that the skeletons date from this early stage of emplacement having undergone modifications whenever light snowmelt occurred or salt concentrations lowered the freezing temperature to maintain water as liquid. Correlation of the Coleoptera species with cultured bacteria in the sample and the likelihood of co-habitation with Beauveria bassiani found in two adjacent, although younger paleosols, leads to new questions about the antiquity of the Coleoptera and the source of N and glucose from chitinase derived from the insects. The skeletons in the 831 section may date close to the oldest preserved chitin (Oligocene) yet found on Earth. While harsh Martian conditions make it seemingly intolerable for complex, multicellular organisms such as insects to exist in the near-surface and subaerially, life within similar cold, dry paleosol microenvironments (Cryosols) of Antarctica point to life potential for the Red Planet, especially when considering the relatively diverse microbe (bacteria and fungi) population. (C) 2011 Elsevier Ltd. All rights reserved.

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Variations in the phase angle difference between a remote 11kV connected wind farm and the centre of Belfast during a typical working day are investigated in the paper. The results obtained using phasor measurement units (PMUs) are compared with the data generated using a PSS/E simulator configured to model the N.Ireland network. The study investigates the effect of changes in the load demand and the wind farm output power on the phase angles at various locations on the network. The paper finally describes how a major system disturbance on the All-Ireland network was monitored and analysed using PMUs located at Queen's University, Belfast and University College Dublin. ©2007 IEEE.

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This paper presents a case-study of a PMU application with PSS support in a real large scale Chinese power system to suppress inter-area oscillations. The paper uses PMU measured feedback signals from a PSS input signal for dynamic torque analysis (DTA). In the paper, a mathematical model of multi-machine power system is described, followed by formation of the residue and DTA indices. Simulations of the model are used with a large-scale power system model to demonstrate the role of PSS and the equivalence of DTA residue indices.

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A PMU based WAMS is to be placed on a weakly coupled section of distribution grid, with high levels of distributed generation. In anticipation of PMU data a Siemens PSS/E model of the electrical environment has been used to return similar data to that expected from the WAMS. This data is then used to create a metric that reflects optimization, control and protection in the region. System states are iterated through with the most desirable one returning the lowest optimization metric, this state is assessed against the one returned by PSS/E under normal circumstances. This paper investigates the circumstances that trigger SPS in the region, through varying generation between 0 and 110% and compromising the network through line loss under summer minimum and winter maximum conditions. It is found that the optimized state can generally tolerate an additional 2 MW of generation (3% of total) before encroaching the same thresholds and in one instance moves the triggering to 100% of generation output.

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Since the Oslo Accords were signed between Israel and the Palestinian Liberation Organization (PLO) in September 1993, the international community has supported civil policing programmes. It has done so as part of its development commitments to Palestinian state-building. Such programmes were, until the outbreak of the second Intifada in 2000, largely regarded as successful in terms of supporting the establishment of a Palestinian civil police (PCP). Such programmes were essentially Western imported models which loosely mixed community and public order policing approaches. With re-engagement in the Palestinian security sector (PSS) in the West Bank in 2007, the international community has once again sought to play a major role in PSS reform. This role includes supporting rehabilitation and retraining of the PCP as a principal institution of state-building. Such activities alongside the so-called transformation efforts within the wider realm of the PSS have re-established as their goal law and order. Within the transformation agenda, there are inherent demands with respect to Israel and the Palestinian National Authority's security and counterterrorism agendas. This analysis examines these activities, and accompanying political intent to contend that such approaches are undermining principles of democratic policing including civil police primacy (CPP). CPP reinforces police universality and means supporting rule of law by putting security under governmental control with proper mechanisms of accountability. This article argues that support to the security sector in the West Bank has increasingly only paid lip service or sought to subvert normative approaches to democratic policing.

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The small signal stability of interconnected power systems is one of the important aspects that need to be investigated since the oscillations caused by this kind of instability have caused many incidents. With the increasing penetration of wind power in the power system, particularly doubly fed induction generator (DFIG), the impact on the power system small signal stability performance should be fully investigated. Because the DFIG wind turbine integration is through a fast action converter and associated control, it does not inherently participate in the electromechanical small signal oscillation. However, it influences the small signal stability by impacting active power flow paths in the network and replacing synchronous generators that have power system stabilizer (PSS). In this paper, the IEEE 39 bus test system has been used in the analysis. Furthermore, four study cases and several operation scenarios have been conducted and analysed. The selective eigenvalue Arnoldi/lanczos's method is used to obtain the system eigenvalue in the range of frequency from 0.2 Hz to 2 Hz which is related to electromechanical oscillations. Results show that the integration of DFIG wind turbines in a system during several study cases and operation scenarios give different influence on small signal stability performance.

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Fossil mesofauna and bacteria recovered from a paleosol in a moraine situated adjacent to the inland ice, Antarctica, and dating to the earliest glacial event in the Antarctic Dry Valleys opens several questions. The most important relates to understanding of the mineralogy and chemistry of the weathered substrate habitat in which Coleoptera apparently thrived at some point in the Early/Middle Miocene and perhaps earlier. Here, Coleoptera remains are only located in one of six horizons in a paleosol formed in moraine deposited during the alpine glacial event (> 15 Ma). A tendency for quartz to decrease upward in the section may be a detrital effect or a product of dissolution in the early stage of profile morphogenesis when climate was presumably milder and the depositing glacier of temperate type. Discontinuous distributions of smectite, laumontite, and hexahydrite may have provided nutrients and water to mesofauna and bacteria during the early stage of biotic colonization of the profile. Because the mesofauna were members of burrowing Coleoptera species, future work should assess the degree to which the organisms occupied other sites in the Dry Valleys in the past. Whereas there is no reasonable expectations of finding Coleoptera/insect remains on Mars, the chemistry and mineralogy of the paleosol is within a life expectancy window for the presence of microorganisms, principally bacteria and fungi. Thus, parameters discussed here within this Antarctic paleosol could provide an analogue to identifying similar fossil or life-bearing weathered regolith on Mars.