Signal processing for a laser-Doppler blood perfusion meter

Two signal processing methods for laser-Dopper perfusion velocimetry are presented. The methods are based on the calculation of the moments of the frequency power spectrum. The first uses Vω-filtering (ω is the frequency) with analogous electronics, the second uses signal autocorrelation with digital electronics. Comparison is made with a third instrument: a spectrum analyzer coupled to a computer, using Fourier transform tecniques. The performance of these setups (sensitivity, limit sensitivity and accuracy) are investigated. We propose a calibration standard for signal processors to be used for blood perfusion measurements. The analogous instrument proved to be the cheapest but the digital instrument had the best performance

Farm level factors associated with feather pecking in organic laying hens

Farm-level factors that could be associated with feather pecking of layers kept in organic farming systems were monitored in 63 flocks from 26 farms located in different areas of The Netherlands. Data on housing and management practices were collected and plumage damage as a measure of feather pecking was scored at 50 weeks of age or older. No or little plumage damage was found in 18 (29%) flocks, moderate damage in 12 (19%) flocks and severe damage in 33 (52%) flocks. A high percentage of hens in the flock using the outdoor run, a young age at purchase and an increasing number of cockerels present in the flock were found to significantly decrease feather pecking damage at 50 weeks or older. Factors associated with increased usage of the outdoor run were smaller flock size, a young age at purchase, an increasing number of cockerels present in the flock and a higher percentage of cover in the run. Based on the results organic farmers are likely to benefit from rearing their own layers. They should keep cockerels with their layers. Other practices resulting in low feather pecking damage are stimulating the use of the outdoor run by making it attractive with vegetative or artificial cover or keeping the flock size at around 500 birds

Comparison of four different programs for the analysis of hemispherical photographs using parameters of canopy structure and solar radiation transmittance

There have been many studies involving the use of hemispherical photographs to indirectly estimate canopy structures and forest light environments. A variety of commercial and free software packages are available for the analysis of hemispherical photographs. The costs of investment might represent an advantage of the free programmes over the commercial, but as yet little has been documented about the differences in their outputs and in the technical applications from a user (ecologist and forester) perspective. The objective of the study was to compare the canopy structure variables (canopy openness and effective plant area index) and solar radiation transmission estimates (direct, diffuse and global solar radiation transmittances) from digital hemispherical photographs taken under two forest canopy conditions (gap and closed canopy) in three different broadleaf forest regions (Chile, Germany, Venezuela) and calculated using four different programmes. The hemispherical photographs were analysed using one commercial (HemiView) and three free programmes (Gap Light Analyzer, hemIMAGE and Winphot). The results obtained revealed that all of the programmes computed similar estimates of both canopy structures and below-canopy solar radiation. Only the results relating to the effective plant area index with an ellipsoidal leaf angle distribution made with HemiView and Winphot deviated significantly. Other user aspects are also discussed, such as costs, image formats, computer system requirements, etc.In vielen Studien werden Hemisphärenphotos genutzt um indirekt die Kronenstruktur und die Belichtungsverhältnisse zu schätzen. Verschiedene kommerzielle und kostenfreie Softwarepakete sind zu Analyse von Hemisphärenphotos verfügbar. Es gibt bisher keine umfassende Vergleichsstudie zu Ergebnissen oder technischer Handhabung aus Sicht der Nutzer dieser Programme (Ökologen und Forstwissenschaftler). Das Ziel dieser Studie war der Vergleich der Schätzungen von Kronenstrukturvariablen (Kronenöffnung und effektiver Pflanzenflächenindex) Solartransmission (direkte, diffuse und Global-Strahlung) aus digitalen Hemisphärenphotos berechnet mit vier verschiedenen Programmen (kostenpflichtig: Hemi- View und frei: Gap Light Analyzer, hemIMAGE and Winphot). Die verwendeten Photos stammen aus drei verschiedenen Laubwaldregionen (Chile, Deutschland und Venezuela) und repräsentieren jeweils Verhältnisse unter geschlossenem Kronendach und in Lücken. Die ermittelten Schätzungen für die verschiedenen Strukturvariablen und Einstrahlungsverhältnisse zeigten eine sehr hohe Übereinstimmung. Einzig der effektive Pflanzenflächenindex basierend auf ellipsoider Blattwinkelverteilung unterschied sich signifikant zwischen den Programmen. Weitere für Nutzer interessante Aspekte wie Kosten, Bildformate, Systemvoraussetzungen und mehr wurden verglichen und diskutiert

The Mellin Transform Technique for the Extraction of the Gluon Density

A new method is presented to determine the gluon density in the proton from jet production in deeply inelastic scattering. By using the technique of Mellin transforms not only for the solution of the scale evolution equation of the parton densities but also for the evaluation of scattering cross sections, the gluon density can be extracted in next-to-leading order QCD. The method described in this paper is, however, more general, and can be used in situations where a repeated fast numerical evaluation of scattering cross sections for varying parton distribution functions is required.Comment: 13 pages (LaTeX); 2 figures are included via epsfig; the corresponding postscript files are uuencode

Anisotropic diffusion in confined colloidal dispersions: The evanescent diffusivity

We employ an analogy to traditional dynamic light scattering to describe the inhomogeneous and anisotropic diffusion of colloid particles near a solid boundary measured via evanescent wave dynamic light scattering. Following this approach, we generate new expressions for the short-time self- and collective diffusivities of colloidal dispersions with arbitrary volume fraction. We use these expressions in combination with accelerated Stokesian dynamics simulations to calculate the diffusivities in the limit of large and small scattering wave numbers for evanescent penetration depths ranging from four particle radii to one-fifth of a particle radius and volume fractions from 10% to 40%. We show that at high volume fractions, and larger penetration depths, the boundaries have little effect on the dynamics of the suspension parallel to the wall since, to a first approximation, the boundary acts hydrodynamically much as another nearby particle. However, near and normal to the wall, the diffusivity shows a strong dependence on penetration depth for all volume fractions. This is due to the lubrication interactions between the particles and the boundary as the particle moves relative to the wall. These results are novel and comprehensive with respect to the range of penetration depth and volume fraction and provide a complete determination of the effect of hydrodynamic interactions on colloidal diffusion adjacent to a rigid boundary

Competences of IT Architects

The field of architecture in the digital world uses a plethora of terms to refer to different kinds of architects, and recognises a confusing variety of competences that these architects are required to have. Different service providers use different terms for similar architects and even if they use the same term, they may mean something different. This makes it hard for customers to know what competences an architect can be expected to have.\ud \ud This book combines competence profiles of the NGI Platform for IT Professionals, The Open Group Architecture Framework (TOGAF), as well as a number of Dutch IT service providers in a comprehensive framework. Using this framework, the book shows that notwithstanding a large variety in terminology, there is convergence towards a common set of competence profiles. In other words, when looking beyond terminological differences by using the framework, one sees that organizations recognize similar types of architects, and that similar architects in different organisations have similar competence profiles. The framework presented in this book thus provides an instrument to position architecture services as offered by IT service providers and as used by their customers.\ud \ud The framework and the competence profiles presented in this book are the main results of the special interest group “Professionalisation” of the Netherlands Architecture Forum for the Digital World (NAF). Members of this group, as well as students of the universities of Twente and Nijmegen have contributed to the research on which this book is based

Search for QCD-instanton induced events in deep inelastic ep scattering at HERA

A search for QCD-instanton-induced events in deep inelastic ep scattering has been performed with the ZEUS detector at the HERA collider, using data corresponding to an integrated luminosity of 38 pb-1. A kinematic range defined by cuts on the photon virtuality, Q2 > 120 GeV2, and on the Bjorken scaling variable, x > 10-3, has been investigated. The QCD-instanton induced events were modelled by the Monte Carlo generator QCDINS. A background-independent, conservative 95% confidence level upper limit for the instanton cross section of 26 pb is obtained, to be compared with the theoretically expected value of 8.9 pb

Einfluss der Art der Materialgewinnung auf die Diagnosefindung in der Lungenpathologie

Das Ziel der Arbeit ist die Darstellung der Möglichkeiten der Kryobiopsien für die Diagnostik von Lungenerkrankungen und Pleuraerkrankungen. Es wurde zunächst gezeigt, dass die transbronchialen Kryobiopsien einen deutlichen morphologischen Unterschied gegenüber den konventionellen transbronchialen Biopsien zeigen, indem sie größer sind und häufiger alveoläres Gewebe enthalten. Entnahmebedingte Artefakte des alveolären Gewebes zeigten sich nicht. Untersucht wurden Patientenkollektive mit Krebserkrankungen sowie mit interstitiellen Lungenerkrankungen. In beiden Gruppen zeigt sich eine deutliche Steigerung der diagnostischen Ausbeute. Bei den pleuralen Läsionen konnte mindestens eine Gleichwertigkeit der Methode der Kryobiopsie der Pleura mit einer flexiblen Zangenbiopsie gezeigt werden. Die letzte vorgelegte Arbeit zeigt die erste Beschreibung einer durch Kryobiopsie gesicherten diffusen idiopathischen Hyperplasie der neuroendokrinen Zellen (DIPNECH). Insgesamt zeigt sich eine gute Einsetzbarkeit der Methode bei allen Lungen- und Pleuraerkrankungen.The aim of this work is to present a variety of cryobiopsies for the diagnosis of pulmonary and pleural diseases. The first paper describes a distinct morphologic difference between cryobiopsies and traditional transbronchial biopsies. Cryobiopsies reveal to be larger, contain more common alveolar tissue, which does not show any artefacts. The following analyses included patient groups with cancer and interstitial lung diseases. Both groups show a higher diagnostic yield concerning the specific disease. For the pleural lesions it could be demonstrated that there is at least a diagnostic equivalence between cryobiopsy and flexible thoracosopy. Finally, the last paper is a first case report of a cryobiopsy-diagnosed diffuse idiopathic neuroendocrine cell hyperplasia (DIPNECH). Altogether, the method presents itself suitable for application in all groups of lung and pleural diseases