1,999 research outputs found
Early life nutrition and gastrointestinal and allergic outcomes: the Generation R Study
This thesis particularly focused on the outcomes of constipation, celiac disease auto antibodies, asthma-like symptoms, and atopic dermatitis, which are all prevalent in the general population. In line with this, the main goals of this thesis were to assess:
· Infant nutrition:
o Consequences of timing of complementary feeding
o Determinants of dietary patterns in toddlers
· Gastrointestinal outcomes:
o Consequences of celiac disease autoantibodies during pregnancy
o Nutritional and endocrinological determinants of functional constipation in childhood
· Asthma-like symptoms and atopic dermatitis:
o Nutritional determinants of asthma-like symptoms and atopic de
The impact of product complexity on ramp-up performance
Fast product ramp-ups are crucial in consumer electronics because short product lifecycles prevail and profit margins diminish rapidly over time. Yet many companies fail to meet their volume, cost and quality targets and the ramp-up phase remains largely unexplored in new product and supply chain management research. This study identifies the key product characteristics that affect ramp-up performance using operational data from the cell phone industry. We investigate three research questions: (1) How to measure software and hardware complexity characteristics of consumer electronics products – and specifically cell phones? (2) To what extent drive product complexity characteristics manufacturing performance? and (3), in turn, to what extent drive manufacturing performance and complexity characteristics ramp up performance? The findings contribute to operations management literature in three ways: First, our model reflects the growing importance of software characteristics in driving hardware complexity, an aspect that prior empirical ramp-up studies have not yet addressed. Second, specific hardware and software complexity characteristics (i.e., component count, parts coupling and SW code size) primarily drive the performance of the manufacturing system in terms of final yield and effective capacity. And finally, effective capacity together with the novelty aspects of both software and hardware complexity (i.e., SW novelty and product novelty) are the key determinants of ramp-up performance
How does development lead time affect performance over the ramp-up lifecycle? : evidence from the consumer electronics industry
In the fast-paced world of consumer electronics, short development lead times and efficient product ramp-ups are invaluable. The sooner and faster a firm can ramp-up production of a new product, the faster it can start to earn revenues, profit from early market opportunities, establish technology standards and release scarce development resources to support new product development projects. Yet, many companies fail to meet their time-to-market and time-to-volume targets and the complex interrelationships between product characteristics, development lead time and ramp-up performance are largely unexplored. In response to these limitations our study focuses on three research questions: (1) To what extent is ramp-up performance determined by development lead time and product complexity? (2) How do these relationships change in the course of the ramp-up lifecycle? and (3) How can the results be explained? Our results contribute to the field of operations management in three ways. First, we offer a more comprehensive and enriched analysis of the drivers for development lead time and ramp-up performance in the cell phone industry. Second, we demonstrate that late schedule slips – although disastrous for customer relations in which due dates are crucial – provide the opportunity to build up (semi-finished) product buffers which in turn increase the initial ramp-up performance. Third, we show that it is important to take these effects into account in a jointly and lifecycle-dependent manner. Thus, our insights support management efforts to anticipate the consequences of product design decisions, predict development schedule risk levels, and make informed decisions about production volume commitments
Inference of hot star density stream properties from data on rotationally recurrent DACs
The information content of data on rotationally periodic recurrent discrete absorption components (DACs) in hot star wind emission lines is discussed. The data comprise optical depths tau(w,phi) as a function of dimensionless Doppler velocity w=(Deltalambda/lambda(0))(c/v(infinity)) and of time expressed in terms of stellar rotation angle phi. This is used to study the spatial distributions of density, radial and rotational velocities, and ionisation structures of the corotating wind streams to which recurrent DACs are conventionally attributed. The simplifying assumptions made to reduce the degrees of freedom in such structure distribution functions to match those in the DAC data are discussed and the problem then posed in terms of a bivariate relationship between tau(w, phi) and the radial velocity v(r)(r), transverse rotation rate Omega(r) and density rho(r, phi) structures of the streams. The discussion applies to cases where: the streams are equatorial; the system is seen edge on; the ionisation structure is approximated as uniform; the radial and transverse velocities are taken to be functions only of radial distance but the stream density is allowed to vary with azimuth. The last kinematic assumption essentially ignores the dynamical feedback of density on velocity and the relationship of this to fully dynamical models is discussed. The case of narrow streams is first considered, noting the result of Hamann et al. (2001) that the apparent acceleration of a narrow stream DAC is higher than the acceleration of the matter itself, so that the apparent slow acceleration of DACs cannot be attributed to the slowness of stellar rotation. Thus DACs either involve matter which accelerates slower than the general wind flow, or they are formed by structures which are not advected with the matter flow but propagate upstream (such as Abbott waves). It is then shown how, in the kinematic model approximation, the radial speed of the absorbing matter can be found by inversion of the apparent acceleration of the narrow DAC, for a given rotation law. The case of broad streams is more complex but also more informative. The observed tau(w,phi) is governed not only by v(r)(r) and Omega(r) of the absorbing stream matter but also by the density profile across the stream, determined by the azimuthal (phi(0)) distribution function F-0(phi(0)) of mass loss rate around the stellar equator. When F-0(phi(0)) is fairly wide in phi(0), the acceleration of the DAC peak tau(w, phi) in w is generally slow compared with that of a narrow stream DAC and the information on v(r)(r), Omega(r) and F- 0(phi(0)) is convoluted in the data tau(w, phi). We show that it is possible, in this kinematic model, to recover by inversion, complete information on all three distribution functions v(r)(r), Omega(r) and F-0(phi(0)) from data on tau(w, phi) of sufficiently high precision and resolution since v(r)(r) and Omega(r) occur in combination rather than independently in the equations. This is demonstrated for simulated data, including noise effects, and is discussed in relation to real data and to fully hydrodynamic models
Customer evaluations of after-sales service contact modes : an empirical analysis of national culture's consequences
Technological advances extend the after-sales services portfolio from traditional service encounters to voice- and bit-based services. Technology enables service organizations to transcend geographical as well as cultural boundaries. It might even result in geographical convergence, often treated synonymously with cultural convergence. In this paper we address this issue. This paper examines the interaction between perceived service performance and national cultural characteristics in the formation of customer satisfaction for three types of after-sales service contact modes. The results suggest that, in contrast to the traditional face-to-face service encounter, the perceived quality-satisfaction relationship is particularly moderated by national culture in case of an after-sales service contact mode mediated by technology
A Direct Catalytic Synthesis of Sodium Diarylphosphinates and Their Corresponding Acids from Sodium Phosphinate
Does having good articulatory skills lead to more fluent speech in first and second languages?
Speaking fluently requires three main processes to run smoothly: conceptualization, formulation, and articulation. This study investigates to what extent fluency in spontaneous speech in both first (L1) and second (L2) languages can be explained by individual differences in articulatory skills. A group of L2 English learners (n = 51) performed three semispontaneous speaking tasks in their L1 Spanish and in their L2 English. In addition, participants performed articulatory skill tasks that measured the speed at which their articulatory speech plans could be initiated (delayed picture naming) and the rate and accuracy at which their articulatory gestures could be executed (diadochokinetic production). The results showed that fluency in spontaneous L2 speech can be predicted by L1 fluency, replicating earlier studies and showing that L2 fluency measures are, to a large degree, measures of personal speaking style. Articulatory skills were found to contribute modestly to explaining variance in both L1 and L2 fluency.Theoretical and Experimental LinguisticsTeaching and Teacher Learning (ICLON
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