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Deze studie gebruikt het concept voedselomgeving om de brug te maken tussen omgeving en voeding. Het begrip voedselomgeving wijst op de voedingswaarde, voedselveiligheid, prijs, informatie en promotie van voeding in de omgeving waar het dagelijks leven van mensen zich afspeelt. Het is deze omgeving die de mogelijkheden en keuzes bepaalt om een bepaald voedingspatroon te volgen. Duurzame en gezonde voedselomgevingen worden gekenmerkt door een goede bereikbaarheid, beschikbaarheid, betaalbaarheid en zichtbaarheid van gezonde en duurzame voeding, terwijl de keuze voor niet-duurzame en ongezonde voeding wordt afgeraden. Daarenboven zijn voedselomgevingen van grote culturele en sociale betekenis. Deze studie bespreekt op basis van academische literatuur en een aantal voorbeelden het concept ‘gezonde en duurzame voedselomgeving’ als basis voor beleid. De overkoepelende doelstellingen zijn om de impact op het milieu van het voedselsysteem te beperken, en om gezonde voedingspatronen te stimuleren die een antwoord bieden op onder meer de toenemende problematiek van overgewicht en obesitas. Daarnaast zijn er gerelateerde doelstellingen als het versterken van de band tussen producenten en consumenten om zo de vervreemding op vlak van voeding te counteren.

Digital X-ray laminography is a technique for generating sectional images of an object, using an X-ray source and detector that move in opposite directions in planes above and below the object. However, motion of the X-ray source and detector during acquisition causes blurring in the projection images, which in turn leads to blurred reconstructions. To prevent these motion artifacts, both the source and detector need to be still during the X-ray pulse which leads to longer acquisition times. In this paper, we consider a system for continuous digital laminography in which the X-ray source is continuously moving and emitting, which would allow for a higher rotation speed. The inherent motion related blurring in the projections is modeled in the reconstruction algorithm. A preliminary simulation experiment comparing the classical digital laminography with the proposed continuous technique indicates that a higher reconstruction quality can be achieved near the rotation center and less streak artifacts are present, at the cost of a decreasing tangential resolution with increasing distance from the rotation center.

In medical imaging, Chest Tomosynthesis (TS) is a form of limited angle tomography that allows to compute section images of a patient, in planes parallel to a flat panel detector placed behind the patient. Projection images are acquired using an X-ray tube that moves on a linear path with respect to the stationary detector. An important cause of artifacts in TS images are errors in the assumed geometrical setup of the system, especially the orientation of the X-ray tube path with respect to the detector. In this paper, we present a method for correcting errors in the acquisition geometry without the need for a calibration phantom. The method is evaluated on simulation data and experimental acquisitions and proves to substantially reduce reconstruction artifacts caused by geometry mismatches.

Purpose: Projections acquired with continuous gantry rotation may suffer from blurring effects, depending on the rotation speed and the exposure time of each projection. This leads to blurred reconstructions if conventional reconstruction algorithms are applied. In this paper, the authors propose a reconstruction method for fast acquisitions based on a continuously moving and continuously emitting x-ray source. They study the trade-off between total acquisition time and reconstruction quality and compare with conventional reconstructions using projections acquired with a stepwise moving x-ray source. Methods: The authors introduce the algebraic reconstruction technique with angular integration concept, which models the angular integration due to the relative motion of the x-ray source during the projection. Results: Compared to conventional reconstruction from projections acquired with pulsed x-ray emission, the proposed method results in substantially improved reconstruction quality around the center of rotation. Outside this region, the proposed method results in improved radial resolution and a decreased tangential resolution. For a fixed reconstruction quality of this region of interest, the proposed method enables a lower number of projections and thus a faster acquisition. Conclusions: The modeling of the continuous gantry rotation in the proposed method substantially improves the reconstruction quality in a region of interest around the rotation center. The proposed method shows potential for fast region of interest tomography. (C) 2015 American Association of Physicists in Medicine.

An important design aspect in tomographic image reconstruction is the choice between a step-and-shoot protocol versus continuous X-ray tube movement for image acquisition. A step-and-shoot protocol implies a perfectly still tube during X-ray exposure, and hence involves moving the tube to its next position only in between exposures. In a continuous movement protocol, the tube is in a constant motion. The angular integration of the rays inherently produces blurred projections. Conventional reconstruction from such projections leads to blurred reconstructed images, and therefore the projection angles are kept small. Important advantages of a continuous scanning protocol are shorter acquisition times and less demands on modality construction from a mechanical point of view. In this work, the continuous protocol is extended with continuous projections, in which the X-ray source is continuously emitting X-rays over larger angles. The focal spot motion can no longer be ignored and is modeled in the reconstruction. The reconstruction quality is compared with the equivalent step-and-shoot counterpart showing improved results for region of interest tomography.

Due to the globalization and the fragmentation of industrial production processes, the logistics sector, which organizes the linkages between different production plants and the market, is growing fast. This results in an increasing demand for suitable new business locations. Previous research has indicated that accessibility is a key factor in the location decision making process. Though the literature on this subject is extensive, little research has been done to quantify the impact of the different dimensions of accessibility on the location decision process of logistics companies. This paper aims to fill this void in the literature by means of a revealed preference study (using a Geographic Information System (GIS) analysis) and a stated preference study (using a designed discrete choice experiment) in Flanders (Belgium). The results of the revealed preference study served as input to the design of the choice situations in the stated preference study. In this study, the respondents were confronted with a series of choice situations described by means of accessibility variables as well as land rent information. An analysis of the resulting data revealed that land rent is the most important factor in the location choice of logistics companies in Flanders. Access to a port is the one but most important factor, followed by access to a motorway and an inland navigation terminal, and the location in a business park. Finally access to a rail terminal plays no significant role in the location choice of logistics companies in Flanders.