860 research outputs found
De late prehistorie en protohistorie van Holoceen Noord-Nederland:onderzoeksagenda, versie 2.0
Opgraving Wartena-Noord 2013 (GIA-131):onderzoek aan een huisterp en een oud verkavelingspatroon in het Friese klei-op-veengebied tussen Warten en Warstiens
Opgraving Wartena-Noord 2013 (GIA-131):onderzoek aan een huisterp en een oud verkavelingspatroon in het Friese klei-op-veengebied tussen Warten en Warstiens
Cross-linguistic study of vocal pathology: perceptual features of spasmodic dysphonia in French-speaking subjects
Clinical characterisation of Spasmodic Dysphonia of the adductor type (SD) in French speakers by Klap and colleagues (1993) appears to differ from that of SD in English. This perceptual analysis aims to describe the phonetic features of French SD. A video of 6 French speakers with SD supplied by Klap and colleagues was analysed for frequency of phonatory breaks, pitch breaks, harshness, creak, breathiness and falsetto voice, rate of production, and quantity of speech output. In contrast to English SD, the French speaking SD patients demonstrated no evidence pitch breaks, but phonatory breaks, harshness and breathiness were prominent features. This verifies the French authors’ (1993) clinical description. These findings suggest that phonetic properties of a specific language may affect the manifestation of pathology in neurogenic voice disorders
A Dynamic Programming Approach to Adaptive Fractionation
We conduct a theoretical study of various solution methods for the adaptive
fractionation problem. The two messages of this paper are: (i) dynamic
programming (DP) is a useful framework for adaptive radiation therapy,
particularly adaptive fractionation, because it allows us to assess how close
to optimal different methods are, and (ii) heuristic methods proposed in this
paper are near-optimal, and therefore, can be used to evaluate the best
possible benefit of using an adaptive fraction size.
The essence of adaptive fractionation is to increase the fraction size when
the tumor and organ-at-risk (OAR) are far apart (a "favorable" anatomy) and to
decrease the fraction size when they are close together. Given that a fixed
prescribed dose must be delivered to the tumor over the course of the
treatment, such an approach results in a lower cumulative dose to the OAR when
compared to that resulting from standard fractionation. We first establish a
benchmark by using the DP algorithm to solve the problem exactly. In this case,
we characterize the structure of an optimal policy, which provides guidance for
our choice of heuristics. We develop two intuitive, numerically near-optimal
heuristic policies, which could be used for more complex, high-dimensional
problems. Furthermore, one of the heuristics requires only a statistic of the
motion probability distribution, making it a reasonable method for use in a
realistic setting. Numerically, we find that the amount of decrease in dose to
the OAR can vary significantly (5 - 85%) depending on the amount of motion in
the anatomy, the number of fractions, and the range of fraction sizes allowed.
In general, the decrease in dose to the OAR is more pronounced when: (i) we
have a high probability of large tumor-OAR distances, (ii) we use many
fractions (as in a hyper-fractionated setting), and (iii) we allow large daily
fraction size deviations.Comment: 17 pages, 4 figures, 1 tabl
From planning the port/city to planning the port-city : exploring the economic interface in European port cities
In last three decades, planning agencies of most ports have institutionally evolved into a (semi-) independent port authority. The rationale behind this process is that port authorities are able to react more quickly to changing logistical and spatial preferences of maritime firms, hence increasing the competitiveness of ports. Although these dedicated port authorities have proven to be largely successful, new economic, social, and environmental challenges are quickly catching up on these port governance models, and particularly leads to (spatial) policy ‘conflicts’ between port and city. This chapter starts by assessing this conflict and argue that the conflict is partly a result of dominant—often also academic—spatial representations of the port city as two separate entities. To escape this divisive conception of contemporary port cities, this chapter presents a relational visualisation method that is able to analyse the economic interface between port and city. Based on our results, we reflect back on our proposition and argue that the core challenge today for researchers and policy makers is acknowledging the bias of port/city, being arguably a self-fulfilling prophecy. Hence, we turn the idea of (planning the) port/city conflicts into planning the port-city’s strengths and weaknesses
Measurement of the Probability Distribution of Total Transmission in Random Waveguides
Measurements have been made of the probability distribution of total
transmission of microwave radiation in waveguides filled with randomly
positioned scatterers which would have values of the dimensionless conductance
g near unity. The distributions are markedly non-Gaussian and have exponential
tails. The measured distributions are accurately described by diagrammatic and
random matrix calculations carried out for nonabsorbing samples in the limit g
>> 1 when g is expressed in terms of the variance of the distribution, which
equals the degree of long-range intensity correlation across the output face of
the sample.Comment: 5 pages, 5 post script figures, RevTe
Effect of incoherent scattering on shot noise correlations in the quantum Hall regime
We investigate the effect of incoherent scattering in a Hanbury Brown and
Twiss situation with electrons in edge states of a three-terminal conductor
submitted to a strong perpendicular magnetic field. The modelization of
incoherent scattering is performed by introducing an additional voltage probe
through which the current is kept equal to zero which causes voltage
fluctuations at this probe. It is shown that inelastic scattering can lead in
this framework to positive correlations, whereas correlations remain always
negative for quasi-elastic scattering.Comment: 5 pages latex, 5 eps figure
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