Heat Conduction in two-dimensional harmonic crystal with disorder

We study the problem of heat conduction in a mass-disordered two-dimensional harmonic crystal. Using two different stochastic heat baths, we perform simulations to determine the system size (L) dependence of the heat current (J). For white noise heat baths we find that J ~ 1/L^a with $a \approx 0.59$ while correlated noise heat baths gives $a \approx 0.51$. A special case with correlated disorder is studied analytically and gives a=3/2 which agrees also with results from exact numerics.Comment: Revised version. 4 pages, 3 figure

A constant travel time budget? In search for explanations for an increase in average travel time

Recent research suggests that during the past decades the average travel time of the Dutch population has probably increased. However, different datasources show different levels of increase. Possible causes of the increase in average travel time are presented here. Increased incomes have probablyresulted in an increase in both costs and benefits of travel. The increase in travel time may also be due to benefits having increased more rapidly than costs. Costs may even have decreased due to the increased comfort level of cars and increased opportunities offered to make double use of one's time(e.g. working in a train)

An optical study of interdiffusion in ZnSe/ZnCdSe

Copyright 1996 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. This article appeared in Applied Physics Letters 69, 1579 (1996) and may be found at

Global Journalist: Singapore confronts a second coronavirus

On this April 27, 2020 program, veteran news editors in Singapore discussed how journalists there are adapting to COVID-19 by applying the lessons learnt from SARS, another coronavirus which hit the country in 2003. Host: Aqil Hamzah. Guests: P.N Balji, Eugene Wee

Endoscopic orbital decompression for Graves' ophthalmopathy

Graves’ disease may occasionally result in significant proptosis that is either cosmetically unacceptable or causes visual loss. This has traditionally been managed surgically by external decompression of the orbital bony skeleton. Trans-nasal endoscopic orbital decompression is emerging as a new minimally-invasive technique, that avoids the need for cutaneous or gingival incisions. Decompression of the medial orbital wall can be performed up to the anterior wall of the sphenoid sinus. This can be combined with resection of the medial and posterior portion of the orbital floor (preserving the infra-orbital nerve). This technique produces decompression which is comparable to external techniques. We present a series of 10 endoscopic orbital decompressions with an average improvement of 4.4 mm in orbital proptosis. There was an improvement in visual acuity in all patients with visual impairment. Endoscopic orbital decompression is recommended as an alternative to traditional decompression techniques.Desmond T. H. Wee, A. Simon Carney, Mark Thorpe and Peter J. Wormal

Competition, autonomy, and prestige: Mechanisms through which the Dark Triad predict job satisfaction

Organizational researchers increasingly recognize the need to consider the Dark Triad traits (i.e., psychopathy, Machiavellianism, and narcissism) when explaining undesirable work outcomes (e.g., counterproductive behaviors). However, little research has focused on the motivations of those who actually hold the traits. In this study (N= 361) we examined how the Dark Triad traits predispose individuals to perceive situations as competitive, prestigious, and comprised of restrictions (i.e., autonomy) which differentially predict job satisfaction. Individuals high on psychopathy and Machiavellianism perceived their workplaces as competitive, whereas individuals high on narcissism perceived their workplaces as prestigious and with fewer restrictions. Sex differences in perceptions were fully mediated by psychopathy and Machiavellianism. We discuss our results from an Evolutionary Industrial/Organization Psychology framework

Transport Modelling During Preparation of General Plans in Big Cities: Reasons and Challenges

Rapidly growing mobility of people in European cities attaches greater importance to the sustainable developmentconcept. The dynamics of European cities are however different. Cites such as Lithuanian, Slovakian and Polishones will rapidly increase traffic flows and car ownership at fast pace. Also in most of Western Europe, even if at lowerrates, private mobility is increasing. In some cities, however, car use and car ownership are finally decreasing, alsothanks to policies implemented. Of course, an increase of traffic flows poses problems in terms of street space, pollutionand liveability of cities. Sustainable integration of all kinds of transport into the urban development process is one ofthe most effective actions in the hands of city planners. The coordination between the planning of residential and businessdevelopment areas and the expansion of public transport and its hierarchical integration is however a difficult butnecessary exercise. Transport modelling tools, in particular, need important advancements to integrate transport andland use in simulations. This article analyses the main challenges in the use of transport models to support the constructionof city plans by means of two case studies of Milan and Vilnius. The analysis deals both with traditional aspects,such as the proper simulation of multimodal choices, the level of detail of zoning, the issues associated to the simulationof traffic management policies. Then, we will focus on two aspects still open: the integration of transport modelling andeconomic assessment or ranking of actions, and the inclusion of land use changes in the modelling

Activity Recognition from Physiological Data using Conditional Random Fields

We describe the application of conditional random fields (CRF) to physiological data modeling for the application of activity recognition. We use the data provided by the Physiological Data Modeling Contest (PDMC), a Workshop at ICML 2004. Data used in PDMC are sequential in nature: they consist of physiological sessions, and each session consists of minute-by-minute sensor readings. We show that linear chain CRF can effectively make use of the sequential information in the data, and, with Expectation Maximization, can be trained on partially unlabeled sessions to improve performance. We also formulate a mixture CRF to make use of the identities of the human subjects to further improve performance. We propose that mixture CRF can be used for transfer learning, where models can be trained on data from different domains. During testing, if the domain of the test data is known, it can be used to instantiate the mixture node, and when it is unknown (or when it is a completely new domain), the marginal probabilities of the labels over all training domains can still be used effectively for prediction.Singapore-MIT Alliance (SMA

The activation energy for GaAs/AlGaAs interdiffusion

Copyright 1997 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. This article appeared in Journal of Applied Physics 82, 4842 (1997) and may be found at