952 resultados para cluster impact ratio


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Crotonaldehyde (2-butenal) adsorption over gold sub-nanometer particles, and the influence of co-adsorbed oxygen, has been systematically investigated by computational methods. Using density functional theory, the adsorption energetics of crotonaldehyde on bare and oxidised gold clusters (Au , d = 0.8 nm) were determined as a function of oxygen coverage and coordination geometry. At low oxygen coverage, sites are available for which crotonaldehyde adsorption is enhanced relative to bare Au clusters by 10 kJ mol. At higher oxygen coverage, crotonaldehyde is forced to adsorb in close proximity to oxygen weakening adsorption by up to 60 kJ mol relative to bare Au. Bonding geometries, density of states plots and Bader analysis, are used to elucidate crotonaldehyde bonding to gold nanoparticles in terms of partial electron transfer from Au to crotonaldehyde, and note that donation to gold from crotonaldehyde also becomes significant following metal oxidation. At high oxygen coverage we find that all molecular adsorption sites have a neighbouring, destabilising, oxygen adatom so that despite enhanced donation, crotonaldehyde adsorption is always weakened by steric interactions. For a larger cluster (Au, d = 1.1 nm) crotonaldehyde adsorption is destabilized in this way even at a low oxygen coverage. These findings provide a quantitative framework to underpin the experimentally observed influence of oxygen on the selective oxidation of crotyl alcohol to crotonaldehyde over gold and gold-palladium alloys. © 2014 the Partner Organisations.

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Emerging vehicular comfort applications pose a host of completely new set of requirements such as maintaining end-to-end connectivity, packet routing, and reliable communication for internet access while on the move. One of the biggest challenges is to provide good quality of service (QoS) such as low packet delay while coping with the fast topological changes. In this paper, we propose a clustering algorithm based on minimal path loss ratio (MPLR) which should help in spectrum efficiency and reduce data congestion in the network. The vehicular nodes which experience minimal path loss are selected as the cluster heads. The performance of the MPLR clustering algorithm is calculated by rate of change of cluster heads, average number of clusters and average cluster size. Vehicular traffic models derived from the Traffic Wales data are fed as input to the motorway simulator. A mathematical analysis for the rate of change of cluster head is derived which validates the MPLR algorithm and is compared with the simulated results. The mathematical and simulated results are in good agreement indicating the stability of the algorithm and the accuracy of the simulator. The MPLR system is also compared with V2R system with MPLR system performing better. © 2013 IEEE.

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This paper explores experimentally the impairments in performance that are generated when multiple single-sideband (SSB) subcarrier multiplexing (SCM) signals are closely allocated in frequency to establish a spectrally efficient wavelength division multiplexing (WDM) link. The performance of cost-effective SSB WDM/ SCM implementations, without optical filters in the transmitter, presents a strong dependency on the imperfect sideband suppression ratio that can be directly achieved with the electro-optical modulator. A direct detected broadband multichannel SCM link composed of a state-of-the-art optical IQ modulator and five quadrature phase-shift keyed (QPSK) subcarriers per optical channel is presented, showing that a suppression ratio of 20 dB obtained directly with the modulator produced a penalty of 2 dB in overall performance, due to interference between adjacent optical channels.

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The UK has a relatively low ratio of business R&D to GDP (the BERD ratio) compared to other leading economies. There has also been a small decline in UK’s BERD ratio in the 1990s, whereas other leading economies have experienced small rises. The relatively low BERD ratio cannot be explained solely by sectoral or industry-level differences between the UK and other countries. There is, therefore, considerable interest in understanding the firm-level determinants of investment in R&D. This report was commissioned by the DTI to analyse the link between R&D and productivity for a sample of firms derived from merging the ONS’s Business Research and Development Database (BERD) and the Annual Respondents Database (ARD). The analysis estimates the private rates of returns to R&D, and not the social rates of return, since it is the private returns that should drive firms’ decisions. A key objective of this research is to analyse the productivity of R&D in small and medium sized enterprises (SME). The analysis is intended to allow comparisons to the results in Rogers (2005), which uses publicly available data on R&D in medium to large UK firms in the 1990s.

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Objectives - In line with a national policy to move care ‘closer to home’, a specialist children's hospital in the National Health Service in England introduced consultant-led ‘satellite’ clinics to two community settings for general paediatric outpatient services. Objectives were to reduce non-attendance at appointments by providing care in more accessible locations and to create new physical clinic capacity. This study evaluated these satellite clinics to inform further development and identify lessons for stakeholders. Methods - Impact of the satellite clinics was assessed by comparing community versus hospital-based clinics across the following measures: (1) non-attendance rates and associated factors (including patient characteristics and travel distance) using a logistic regression model; (2) percentage of appointments booked within local catchment area; (3) contribution to total clinic capacity; (4) time allocated to clinics and appointments; and (5) clinic efficiency, defined as the ratio of income to staff-related costs. Results - Satellite clinics did not increase attendance beyond their contribution to shorter travel distance, which was associated with higher attendance. Children living in the most-deprived areas were 1.8 times more likely to miss appointments compared with those from least-deprived areas. The satellite clinics’ contribution to activity in catchment areas and to total capacity was small. However, one of the two satellite clinics was efficient compared with most hospital-based clinics. Conclusions - Outpatient clinics were relocated in pragmatically chosen community settings using a ‘drag and drop’ service model. Such clinics have potential to improve access to specialist paediatric healthcare, but do not provide a panacea. Work is required to improve attendance as part of wider efforts to support vulnerable families. Satellite clinics highlight how improved management could contribute to better use of existing capacity.

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Advanced signal processing, such as multi-channel digital back propagation and mid span optical phase conjugation, can compensate for inter channel nonlinear effects in point to point links. However, once such are effects are compensated, the interaction between the signal and noise fields becomes dominant. We will show that this interaction has a direct impact on the signal to noise ratio improvement, observing that ideal optical phase conjugation offers 1.5 dB more performance benefit than DSP based compensation.

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OBJECTIVE: Our aim was to study the impact of depressive disorders on work disability to discover the determinants of depression for work disability in the European countries. DESIGN: The sample was composed of 31,126 individuals from 29 countries included in the 2002 World Health Survey of the World Health Organization. National representative samples of countries from all regions of Europe and with different levels of economic development and health coverage were selected. RESULTS: Estimates of people not working because of ill health did not differ among European countries in relation to levels of economic development or health coverage. Significant determinants of people with diagnosis of depression not working because of ill health (reference category) versus working were age (odds ratio = 0.97), female sex (odds ratio = 1.71), education (odds ratio = 1.11), marital status (being unmarried indicating less probability), lowest income level, and comorbidity with angina pectoris (odds ratio = 0.51). Moreover, according to previous studies, we found some determinants (comorbidity with other diseases, young age, and unemployment) impacting on health status. CONCLUSIONS: Depression is a substantial cause of work disability and it is a complex phenomenon that involves many variables. Investigation into this relationship should improve, focusing on the role of determinants.

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Noha az 1990-es évek első felében felbomlott az akadémiai közgazdászok sok évtizeden át örök érvényűnek hitt közmegegyezése a minimálbér szükségképpen negatív foglalkoztatási hatásáról, a túlságosan magas minimálbért minden közgazdász foglalkoztatáscsökkentő hatásúnak jósolja. Tanulmányunkban a magyar minimálbér-szabályozást e hatás szempontjából vizsgáljuk és értékeljük. / === / Although the long-held view of an unambiguously negative employment effect of a binding minimum wage was challenged by empirical findings in the early 1990’s, it is unanimously predicted that if the minimum wage is set too high it will bring about adverse employment effects. Accordingly, our study starts from an evaluation of the magnitude of the Hungarian minimum wage, i.e., of how it relates to minimum wage rates elsewhere, and of how it has developed through time. Next we inspect the main features that characterize the Hungarian system of minimum wage regulation. Theoretical views on the potential employment effect of minimum wage regulation are then surveyed and contrasted to empirical findings. The study concludes by policy recommendations. To sum up the main strand of arguments, we try to demonstrate that even though Hungary’s minimum wage, if assessed by its ratio to average and/or median full-time earnings, does not appear particularly high by international standards, it might rightly be regarded as unreasonably high in light of Hungary’s excessively low relative rate of employment among the least schooled. This diagnose should become particularly evident once one takes into account that, in sharp contrast to established rules elsewhere, a significantly higher wage floor is in effect for those with lower secondary schooling. Abolition of this legally guaranteed premium over the minimum wage as well as more moderation in minimum wage adjustments are thus highly recommended.

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Lean manufacturing (LM) is currently enjoying its second heyday. Companies in several industries are implementing leanpractices to keep pace with the competition and achieve better results. In this article, we will concentrate on how companies can improve their inventoryturnover performance through the use ofleanpractices. According to our main proposition, firms that widely apply leanpractices have higher inventoryturnover than those that do not rely on LM. However, there may be significant differences in inventoryturnover even among lean manufacturers depending on their contingencies. Therefore, we also investigate how various contingency factors (production systems, order types, product types) influence theinventoryturnoveroflean manufacturers. We use cluster and correlation analysis to separate manufacturers based onthe extent of their leanness and to examine the effect of contingencies. We acquired the data from the International Manufacturing Strategy Survey (IMSS) in ISIC sectors 28–35.

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In the past few years, several papers have been published in the international literature on the impact of the economic crisis on health and health care. However, there is limited knowledge on this topic regarding the Central and Eastern European (CEE) countries. The main aims of this study are to examine the effect of the financial crisis on health care spending in four CEE countries (the Czech Republic, Hungary, Poland and Slovakia) in comparison with the OECD countries. In this paper we also revised the literature for economic crisis related impact on health and health care system in these countries. OECD data released in 2012 were used to examine the differences in growth rates before and after the financial crisis. We examined the ratio of the average yearly growth rates of health expenditure expressed in USD (PPP) between 2008–2010 and 2000–2008. The classification of the OECD countries regarding “development” and “relative growth” resulted in four clusters. A large diversity of “relative growth” was observed across the countries in austerity conditions, however the changes significantly correlate with the average drop of GDP from 2008 to 2010. To conclude, it is difficult to capture visible evidence regarding the impact of the recession on the health and health care systems in the CEE countries due to the absence of the necessary data. For the same reason, governments in this region might have a limited capability to minimize the possible negative effects of the recession on health and health care systems.

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In the past few years, several papers have been published in the international literature on the impact of the economic crisis on health and health care. However, there is limited knowledge on this topic regarding the Central and Eastern European (CEE) countries. The main aims of this study are to examine the effect of the financial crisis on health care spending in four CEE countries (the Czech Republic, Hungary, Poland and Slovakia) in comparison with the OECD countries. In this paper we also revised the literature for economic crisis related impact on health and health care system in these countries. OECD data released in 2012 were used to examine the differences in growth rates before and after the financial crisis. We examined the ratio of the average yearly growth rates of health expenditure expressed in USD (PPP) between 2008–2010 and 2000–2008. The classification of the OECD countries regarding “development” and “relative growth” resulted in four clusters. A large diversity of “relative growth” was observed across the countries in austerity conditions, however the changes significantly correlate with the average drop of GDP from 2008 to 2010. To conclude, it is difficult to capture visible evidence regarding the impact of the recession on the health and health care systems in the CEE countries due to the absence of the necessary data. For the same reason, governments in this region might have a limited capability to minimize the possible negative effects of the recession on health and health care systems.

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Az írás a globális értékláncok élén álló autóipari cégek világgazdasági válságra adott reakcióit foglalja össze. Megállapítja, hogy a válságnak messze nincs vége: az iparág globális átrendeződése folytatódik. A globális értékláncokba sikeresen betagozódott közép-európai autóipari klaszter ezeknek a folyamatoknak mindmáig nyertese volt. Számolni kell azonban azzal, hogy továbbra is sok a technológiai és a piaci bizonytalanság: az új szereplők belépése, új üzleti modellek elterjedése hosszabb távon felboríthatja a jelenlegi status quo-t, és veszélyeztetheti a hagyományos autóipari befektetőiket munkabér-alapú versenyképességgel megtartani próbáló közép- és kelet-európai országok pozícióit. Az autóipari működő tőkét fogadó közép-kelet-európai országok számára hosszabb távon veszélyt jelenthet az autóipari üzleti modellek átalakulása, a gyártás teljes kiszervezése komplex gyártási szolgáltatást vállaló cégekhez, mivel ez esetben az értéklánc vezető vállalatai bezárhatják a régióban működő gyártóbázisaikat. Az értékláncok élén álló globális cégek „menekülés a minőségbe” stratégiája helyi szinten is követhető, követendő, a működő tőkét fogadó országok versenyképessége kizárólag a helyi leányvállalatok állandó „feljebb lépésével” tartható fenn. ______ This paper summarizes lead firms’ reactions to crisis in global automotive value chains. The paper advances five theses. Author argues that crisis is not over yet, the global restructuring of the industry continues. Actors in the CEE automotive cluster have successfully become integrated into global value chains and have thereby been the winners of past restructuring processes. Nevertheless, technological and market uncertainties prevail: entry of new economic actors and the diffusion of new business models may, in the long run, disrupt the current status quo and jeopardise the world economic position of CEE countries that have been relying solely on their labour cost advantages to sustain direct investment inflows in their automotive industries. In the long run the automotive industries of Central and Eastern European (CEE) economies may become threatened by the transformation of the prevailing automotive business model, the outsourcing of manufacturing and related support activities to complex manufacturing services providers, which could lead to the closure of lead firms’ manufacturing facilities in CEE. Lead firms’ increased focus on high quality high value adding activities strategy can and should be followed by local subsidiaries through a continuous strive for upgrading.

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Clusters are aggregations of atoms or molecules, generally intermediate in size between individual atoms and aggregates that are large enough to be called bulk matter. Clusters can also be called nanoparticles, because their size is on the order of nanometers or tens of nanometers. A new field has begun to take shape called nanostructured materials which takes advantage of these atom clusters. The ultra-small size of building blocks leads to dramatically different properties and it is anticipated that such atomically engineered materials will be able to be tailored to perform as no previous material could.^ The idea of ionized cluster beam (ICB) thin film deposition technique was first proposed by Takagi in 1972. It was based upon using a supersonic jet source to produce, ionize and accelerate beams of atomic clusters onto substrates in a vacuum environment. Conditions for formation of cluster beams suitable for thin film deposition have only recently been established following twenty years of effort. Zinc clusters over 1,000 atoms in average size have been synthesized both in our lab and that of Gspann. More recently, other methods of synthesizing clusters and nanoparticles, using different types of cluster sources, have come under development.^ In this work, we studied different aspects of nanoparticle beams. The work includes refinement of a model of the cluster formation mechanism, development of a new real-time, in situ cluster size measurement method, and study of the use of ICB in the fabrication of semiconductor devices.^ The formation process of the vaporized-metal cluster beam was simulated and investigated using classical nucleation theory and one dimensional gas flow equations. Zinc cluster sizes predicted at the nozzle exit are in good quantitative agreement with experimental results in our laboratory.^ A novel in situ real-time mass, energy and velocity measurement apparatus has been designed, built and tested. This small size time-of-flight mass spectrometer is suitable to be used in our cluster deposition systems and does not suffer from problems related to other methods of cluster size measurement like: requirement for specialized ionizing lasers, inductive electrical or electromagnetic coupling, dependency on the assumption of homogeneous nucleation, limits on the size measurement and non real-time capability. Measured ion energies using the electrostatic energy analyzer are in good accordance with values obtained from computer simulation. The velocity (v) is measured by pulsing the cluster beam and measuring the time of delay between the pulse and analyzer output current. The mass of a particle is calculated from m = (2E/v$\sp2).$ The error in the measured value of background gas mass is on the order of 28% of the mass of one N$\sb2$ molecule which is negligible for the measurement of large size clusters. This resolution in cluster size measurement is very acceptable for our purposes.^ Selective area deposition onto conducting patterns overlying insulating substrates was demonstrated using intense, fully-ionized cluster beams. Parameters influencing the selectivity are ion energy, repelling voltage, the ratio of the conductor to insulator dimension, and substrate thickness. ^

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Siliceous sponges have survived pre-historical mass extinction events caused by ocean acidification and recent studies suggest that siliceous sponges will continue to resist predicted increases in ocean acidity. In this study, we monitored silica biomineralization in the Hawaiian sponge Mycale grandis under predicted pCO2 and sea surface temperature scenarios for 2100. Our goal was to determine if spicule biomineralization was enhanced or repressed by ocean acidification and thermal stress by monitoring silica uptake rates during short-term (48 h) experiments and comparing biomineralized tissue ratios before and after a long-term (26 d) experiment. In the short-term experiment, we found that silica uptake rates were not impacted by high pCO2 (1050 µatm), warmer temperatures (27°C), or combined high pCO2 with warmer temperature (1119 µatm; 27°C) treatments. The long-term exposure experiments revealed no effect on survival or growth rates of M. grandis to high pCO2 (1198 µatm), warmer temperatures (25.6°C), or combined high pCO2 with warmer temperature (1225 µatm, 25.7°C) treatments, indicating that M. grandis will continue to prosper under predicted increases in pCO2 and sea surface temperature. However, ash-free dry weight to dry weight ratios, subtylostyle lengths, and silicified weight to dry weight ratios decreased under conditions of high pCO2 and combined pCO2 warmer temperature treatments. Our results show that rising ocean acidity and temperature have marginal negative effects on spicule biomineralization and will not affect sponge survival rates of M. grandis.