Numerical Results for the System Noise Temperature of an Aperture Array Tile and Comparison with Measurements

The purpose of this report is to document the noise performance of a complex beamforming array antenna system and to characterize the recently developed noise measurement facility called THACO, which was developed at ASTRON. The receiver system includes the array antenna of strongly coupled 144 TSA elements, 144 Low Noise Amplifiers (LNAs) (Tmin =35-40K) and the data recording/storing facilities of the initial test station that allow for off-line digital beamforming. The primary goal of this study is to compare the measured receiver noise temperatures with the simulated values for several practical beamformers, and to predict the associated receiver noise coupling contribution, antenna thermal noise and ground noise pick-up (due to the back radiation).Comment: ASTRON repor

Financieel-economische aspecten van Biobrandstofproductie : deskstopstudie naar de invloed van co-productie van bio-based producten op de financiële haalbaarheid van biobrandstoffen

Door uitvoering van een deskstop studie heeft WUR, in samenwerking met ECN, onderzocht of co-productie van biobrandstoffen en bio-based producten leidt tot meer marktcompetitieve biobrandstofproductie. De centrale vraagstelling van de studie was of aangetoond kan worden dat “co-productie” resulteert in realisatie van meer marktcompetitieve waardeketens voor grootschalige en duurzame inzet van biomassa in de biobased economy. De studie naar de financiële haalbaarheid van een twaalftal biobrandstofketens laten zien dat co-productie van biobrandstoffen tezamen met bio-based producten een goede methode is om additionele waarde toe te kennen aan de totale biomassa-product-keten. De co-producten die tezamen met biobrandstoffen geproduceerd kunnen worden zijn zeer divers. In het algemeen bestaat er voor deze co-producten een omvangrijke afzetmarkt, en gaat het om producten die op dit moment grotendeels uit aardolie vervaardigd worden. Technologieën voor productie en toepassing van hoogwaardige co-producten die naast biobrandstoffen uit biomassa geproduceerd kunnen worden bevinden zich in verschillende stadia van ontwikkeling

A practical view of fine-mapping and gene prioritization in the post-genome-wide association era

Over the past 15 years, genome-wide association studies (GWASs) have enabled the systematic identification of genetic loci associated with traits and diseases. However, due to resolution issues and methodological limitations, the true causal variants and genes associated with traits remain difficult to identify. In this post-GWAS era, many biological and computational fine-mapping approaches now aim to solve these issues. Here, we review fine-mapping and gene prioritization approaches that, when combined, will improve the understanding of the underlying mechanisms of complex traits and diseases. Fine-mapping of genetic variants has become increasingly sophisticated: initially, variants were simply overlapped with functional elements, but now the impact of variants on regulatory activity and direct variant-gene 3D interactions can be identified. Moreover, gene manipulation by CRISPR/Cas9, the identification of expression quantitative trait loci and the use of co-expression networks have all increased our understanding of the genes and pathways affected by GWAS loci. However, despite this progress, limitations including the lack of cell-type- and disease-specific data and the ever-increasing complexity of polygenic models of traits pose serious challenges. Indeed, the combination of fine-mapping and gene prioritization by statistical, functional and population-based strategies will be necessary to truly understand how GWAS loci contribute to complex traits and diseases

Electromagnetically Induced Transparency with an Ensemble of Donor-Bound Electron Spins in a Semiconductor

We present measurements of electromagnetically induced transparency with an ensemble of donor- bound electrons in low-doped n-GaAs. We used optical transitions from the Zeeman-split electron spin states to a bound trion state in samples with optical densities of 0.3 and 1.0. The electron spin dephasing time T* \approx 2 ns was limited by hyperfine coupling to fluctuating nuclear spins. We also observe signatures of dynamical nuclear polarization, but find these effects to be much weaker than in experiments that use electron spin resonance and related experiments with quantum dots.Comment: 4 pages, 4 figures; Improved analysis of data in Fig. 3, corrected factors of 2 and p

Public exhibit for demonstrating the quantum of electrical conductance

We present a new robust setup that explains and demonstrates the quantum of electrical conductance for a general audience and which is continuously available in a public space. The setup allows users to manually thin a gold wire of several atoms in diameter while monitoring its conductance in real time. During the experiment, a characteristic step-like conductance decrease due to rearrangements of atoms in the cross-section of the wire is observed. Just before the wire breaks, a contact consisting of a single atom with a characteristic conductance close to the quantum of conductance can be maintained up to several seconds. The setup is operated full-time, needs practically no maintenance and is used on different educational levels

Transition Form Factors between Pseudoscalar and Vector Mesons in Light-Front Dynamics

We study the transition form factors between pseudoscalar and vector mesons using a covariant fermion field theory model in $(3+1)$ dimensions. Performing the light-front calculation in the $q^+ =0$ frame in parallel with the manifestly covariant calculation, we note that the suspected nonvanishing zero-mode contribution to the light-front current $J^+$ does not exist in our analysis of transition form factors. We also perform the light-front calculation in a purely longitudinal $q^+ > 0$ frame and confirm that the form factors obtained directly from the timelike region are identical to the ones obtained by the analytic continuation from the spacelike region. Our results for the $B \to D^* l \nu_l$ decay process satisfy the constraints on the heavy-to-heavy semileptonic decays imposed by the flavor independence in the heavy quark limit.Comment: 20 pages, 14 figure

Wonen in Houwerzijl:vind je heil in Houwerzijl!

Deze managementsamenvatting omschrijft kort en bondig het onderzoek naar de woonomgeving van Houwerzijl. Deze samenvatting is bedoeld om de hoofdlijnen van het onderzoek weer te geven, voor het totale onderzoek wordt u doorverwezen naar het onderzoeksrapport ‘Wonen in Houwerzijl’. De doelstelling is het advies geven voor mogelijke aanpassingen ten aanzien van de leefomgeving. De probleemstelling en tevens de onderzoeksvraag van dit onderzoek luidt: ‘Wat vinden de inwoners van Houwerzijl van de kwaliteit van hun leefomgeving en hoe zien zij dit in 2020?’ Deze onderzoeksvraag is verder verdeeld in twee deelvragen, die de woonmotieven en de kwaliteit van de woningen onderzoeken. Studentonderzoek in het kader van het thema Werklandschappen

The Role of Deontic Logic in the Specification of Information Systems

In this paper we discuss the role that deontic logic plays in the specification of information systems, either because constraints on the systems directly concern norms or, and even more importantly, system constraints are considered ideal but violable (so-called `soft¿ constraints).\ud To overcome the traditional problems with deontic logic (the so-called paradoxes), we first state the importance of distinguishing between ought-to-be and ought-to-do constraints and next focus on the most severe paradox, the so-called Chisholm paradox, involving contrary-to-duty norms. We present a multi-modal extension of standard deontic logic (SDL) to represent the ought-to-be version of the Chisholm set properly. For the ought-to-do variant we employ a reduction to dynamic logic, and show how the Chisholm set can be treated adequately in this setting. Finally we discuss a way of integrating both ought-to-be and ought-to-do reasoning, enabling one to draw conclusions from ought-to-be constraints to ought-to-do ones, and show by an example the use(fulness) of this