Modelling and experiments of self-reflectivity under femtosecond ablation conditions

We present a numerical model which describes the propagation of a single femtosecond laser pulse in a medium of which the optical properties dynamically change within the duration of the pulse. We use a Finite Difference Time Domain (FDTD) method to solve the Maxwell's equations coupled to equations describing the changes in the material properties. We use the model to simulate the self-reflectivity of strongly focused femtosecond laser pulses on silicon and gold under laser ablation condition. We compare the simulations to experimental results and find excellent agreement.Comment: 11 pages, 8 figure

Coherent vibrations of submicron spherical gold shells in a photonic crystal

Coherent acoustic radial oscillations of thin spherical gold shells of submicron diameter excited by an ultrashort optical pulse are observed in the form of pronounced modulations of the transient reflectivity on a subnanosecond time scale. Strong acousto-optical coupling in a photonic crystal enhances the modulation of the transient reflectivity up to 4%. The frequency of these oscillations is demonstrated to be in good agreement with Lamb theory of free gold shells.Comment: Error in Eqs.2 and 3 corrected; Tabl. I corrected; Fig.1 revised; a model that explains the dependence of the oscillation amplitude of the transient reflectivity with wavelength adde

The relation between hyperinflation and daily activity in COPD patients

Although we did not find any relation between DH and PA, SH could be a useful marker to indicate reduced PA. Many patients used a decreased tidal volume and pursed-lips breathing to counteract DH. Different correlations between SH and PA were found to be present between subjects who either were or were not engaged in an exercise-training program. Therefore, this stratification should also be investigated in future studies

IDLaS-NL – A platform for running customized studies on individual differences in Dutch language skills via the internet

We introduce the Individual Differences in Language Skills (IDLaS-NL) web platform, which enables users to run studies on individual differences in Dutch language skills via the internet. IDLaS-NL consists of 35 behavioral tests, previously validated in participants aged between 18 and 30 years. The platform provides an intuitive graphical interface for users to select the tests they wish to include in their research, to divide these tests into different sessions and to determine their order. Moreover, for standardized administration the platform provides an application (an emulated browser) wherein the tests are run. Results can be retrieved by mouse click in the graphical interface and are provided as CSV-file output via email. Similarly, the graphical interface enables researchers to modify and delete their study configurations. IDLaS-NL is intended for researchers, clinicians, educators and in general anyone conducting fundamental research into language and general cognitive skills; it is not intended for diagnostic purposes. All platform services are free of charge. Here, we provide a description of its workings as well as instructions for using the platform. The IDLaS-NL platform can be accessed at www.mpi.nl/idlas-nl

Long-range potential fluctuations and 1/f noise in hydrogenated amorphous silicon

We present a microscopic theory of the low-frequency voltage noise (known as "1/f" noise) in micrometer-thick films of hydrogenated amorphous silicon. This theory traces the noise back to the long-range fluctuations of the Coulomb potential produced by deep defects, thereby predicting the absolute noise intensity as a function of the distribution of defect activation energies. The predictions of this theory are in very good agreement with our own experiments in terms of both the absolute intensity and the temperature dependence of the noise spectra.Comment: 8 pages, 3 figures, several new parts and one new figure are added, but no conceptual revision

Investigating the current knowledge and needs concerning a follow-up for long-term cardiovascular risks in Dutch women with a preeclampsia history:a qualitative study

Background There is increasing evidence that a history of preeclampsia is an important risk factor for future cardiovascular events. Awareness of this risk could provide opportunities for identification of women at risk, with opportunities for prevention and / or early intervention. A standardized follow-up has not yet been implemented in the north of the Netherlands. The objective of this qualitative study was to explore the opinions and wishes among women and physicians about the follow-up for women with a history of preeclampsia. Methods Semi-structured interviews with 15 women and 14 physicians (5 obstetricians, 4 general practitioners, 3 vascular medicine specialists and 2 cardiologists) were performed and addressed topics about knowledge on CVR, current - and future follow-up. Women were approached through the HELLP foundation and their physicians. Physicians were approached by email. The interviews were recorded, typed and coded using ATLAS.ti software. A theoretical-driven thematic analysis was performed. Results Women had some knowledge about the association between preeclampsia and the increased CVR, but missed information from their health care providers. Specialists were aware of the association, but the information and advice they provided to their patients was minimal and inconsistent according to themselves. Whereas some general practitioners regarded their own knowledge as limited. There was a clear desire among women for a more extensive follow-up with specific attention to both emotional and physical consequences of preeclampsia. Physicians indicated that they preferred to see a follow up program concerning the CVR at the general practitioner as part of the already existent cardiovascular risk management (CVRM) program. Conclusion Women and medical specialists consider it important to improve aftercare for women after a pregnancy complicated by preeclampsia. Introducing these women into the CVRM program at the general practitioner is regarded as a preferred first step. Further research is warranted to establish an evidence-based guideline for the follow-up of these women

Ioffe Physical-Technical Institute

Abstract We present results of pump-probe anti-Stokes Raman experiments at 1.8 K on the generation of nonequilibrium phonons in a-Si:H following intense optical excitation. We obtained a decay time of &70 ns for the TO phonons in all samples studied. In plasma deposited samples we observed an additional slowly decaying ( <100 ns) contribution to the Raman signal, which was not seen in hot-wire deposited samples. We propose a model to explain the additional phonons as resulting from fast nonradiative recombination of free carriers with carriers localized in the tail states

Shared lexical access processes in speaking and listening? An individual differences study

- * indicates joint first authorship - Lexical access is a core component of word processing. In order to produce or comprehend a word, language users must access word forms in their mental lexicon. However, despite its involvement in both tasks, previous research has often studied lexical access in either production or comprehension alone. Therefore, it is unknown to which extent lexical access processes are shared across both tasks. Picture naming and auditory lexical decision are considered good tools for studying lexical access. Both of them are speeded tasks. Given these commonalities, another open question concerns the involvement of general cognitive abilities (e.g., processing speed) in both linguistic tasks. In the present study, we addressed these questions. We tested a large group of young adults enrolled in academic and vocational courses. Participants completed picture naming and auditory lexical decision tasks as well as a battery of tests assessing non-verbal processing speed, vocabulary, and non-verbal intelligence. Our results suggest that the lexical access processes involved in picture naming and lexical decision are related but less closely than one might have thought. Moreover, reaction times in picture naming and lexical decision depended as least as much on general processing speed as on domain-specific linguistic processes (i.e., lexical access processes)