1,026 research outputs found
Species Composition of Benthic Diatoms and Distribution of Chlorophyll a on an Intertidal Flat in the Dutch Wadden Sea
A linear transect with 12 sampling points was sampled in a tidal estuarine environment during 1973 for chlorophyll a and pheophytin, and for species composition of epipelic diatoms. A gradual pattern in sediment from coarse to fine was found from the most seaward station towards the most landward station of the transect. Differences in station level gave emersion times of 37 to 67 % of the tidal cycle. In the course of the year, fluctuations in chlorophyll a content (mg chlorophyll a m-* in the top 2 cm of the sediment) appeared to be distinctly parallel at all stations. However, mean yearly values differed widely from station to station, ranging between 20 and 100mg chlorophyll a m-2. Chlorophyll a concentration was positively related to the amount of particles < 16 pm in the sediment; this proportion was considered to relate negatively to the degree of exposure to currents and wave action. It is likely that low daily winter irradiances limited diatom growth. Heavy rain and strong wave action during storms suddenly reduced the chlorophyll a content considerably. Species composition of epipelic benthic diatoms could partly be related to the sediment gradient and time of year. It seems that high biomass values are formed almost exclusively by single species which are indifferent in their spatial distribution
Two-qubit logic between distant spins in silicon
Direct interactions between quantum particles naturally fall off with
distance. For future-proof qubit architectures, however, it is important to
avail of interaction mechanisms on different length scales. In this work, we
utilize a superconducting resonator to facilitate a coherent interaction
between two semiconductor spin qubits 250 m apart. This separation is
several orders of magnitude larger than for the commonly employed direct
interaction mechanisms in this platform. We operate the system in a regime
where the resonator mediates a spin-spin coupling through virtual photons. We
report anti-phase oscillations of the populations of the two spins with
controllable frequency. The observations are consistent with iSWAP oscillations
and ten nanosecond entangling operations. These results hold promise for
scalable networks of spin qubit modules on a chip.Comment: 17 pages, 9 figure
Learning from Sustainability-Oriented Innovation
This chapter argues that insights from the realm of sustainability-oriented innovation can provide useful answers to the question of why Small and Medium-Sized Enterprises (SMEs) would (or should) become interested in implementing responsible innovation practices. It is based on the assumption that âresponsible innovationâ and âsustainability-oriented innovationâ are different approaches aimed at orienting innovation towards increased positive impacts on social and natural environments. Motivations and influences for pursuing sustainability-oriented inno-vation have been studied in the past, and can provide insights into reasons for pursu-ing the implementation of responsible innovation practices
Biosubstraat : Duurzaam substraat op basis van BioFoam
Doelstelling van het project was het ontwikkelen van een hernieuwbare grondstof/substraat, welke voldoet aan de wensen en eisen van de kwekers en waar een kwalitatief goed product op geteeld kan worden met handhaving of verbetering van het rendement. Het belangrijkste eindproduct is een bio substraat op basis van gemodificeerde BioFoam. De volgende activiteiten hebben bijgedragen aan het realiseren van de doelstelling: âą Het ontwikkelen en produceren van diverse varianten gemodificeerde BioFoam en het uitvoeren van een aantal fysische en chemische testen in het laboratorium. âą Het bepalen van belangrijke eigenschappen van deze gemodificeerde BioFoam als substraat in combinatie en vergelijking tot andere grondstoffen in het laboratorium âą Het uitvoeren van diverse teeltproeven met mengsels van BioFoam met andere grondstoffen âą Het in beeld brengen van de voordelen met betrekking tot de ketenkosten. Er is maar een teeltjaar (alleen 2012) gebruikt om testen uit te voeren. Ketens moeten daarom nog deels opgezet worden. âą Op basis van de (teelt)proeven zijn wel meer partijen bij het project betrokken geraakt en heeft de markt belangstelling getoond. Het belangrijkste eindproduct is een getest substraat op basis van gemodificeerde BioFoam
Long-term Exposure to Traffic-related Air Pollution and Type 2 Diabetes Prevalence in a Cross-sectional Screening-study in the Netherlands
<p>Abstract</p> <p>Background</p> <p>Air pollution may promote type 2 diabetes by increasing adipose inflammation and insulin resistance. This study examined the relation between long-term exposure to traffic-related air pollution and type 2 diabetes prevalence among 50- to 75-year-old subjects living in Westfriesland, the Netherlands.</p> <p>Methods</p> <p>Participants were recruited in a cross-sectional diabetes screening-study conducted between 1998 and 2000. Exposure to traffic-related air pollution was characterized at the participants' home-address. Indicators of exposure were land use regression modeled nitrogen dioxide (NO<sub>2</sub>) concentration, distance to the nearest main road, traffic flow at the nearest main road and traffic in a 250 m circular buffer. Crude and age-, gender- and neighborhood income adjusted associations were examined by logistic regression.</p> <p>Results</p> <p>8,018 participants were included, of whom 619 (8%) subjects had type 2 diabetes. Smoothed plots of exposure versus type 2 diabetes supported some association with traffic in a 250 m buffer (the highest three quartiles compared to the lowest also showed increased prevalence, though non-significant and not increasing with increasing quartile), but not with the other exposure metrics. Modeled NO<sub>2</sub>-concentration, distance to the nearest main road and traffic flow at the nearest main road were not associated with diabetes. Exposure-response relations seemed somewhat more pronounced for women than for men (non-significant).</p> <p>Conclusions</p> <p>We did not find consistent associations between type 2 diabetes prevalence and exposure to traffic-related air pollution, though there were some indications for a relation with traffic in a 250 m buffer.</p
The LOFAR LBA Sky Survey II. First data release
The Low Frequency Array (LOFAR) is the only existing radio interferometer
able to observe at ultra-low frequencies (<100 MHz) with high resolution (<15")
and high sensitivity (<1 mJy/beam). To exploit these capabilities, the LOFAR
Surveys Key Science Project is using the LOFAR Low Band Antenna (LBA) to carry
out a sensitive wide-area survey at 41-66 MHz named the LOFAR LBA Sky Survey
(LoLSS). LoLSS is covering the whole northern sky above declination 24 deg with
a resolution of 15" and a sensitivity of 1-2 mJy/beam (1 sigma) depending on
declination, field properties, and observing conditions. Here we present the
first data release. An automated pipeline was used to reduce the 95 fields
included in this data release. The data reduction procedures developed for this
project have general application and are currently being used to process LOFAR
LBA interferometric observations. Compared to the preliminary release,
direction-dependent errors have been corrected for during the calibration
process. This results in a typical sensitivity of 1.55 mJy/beam at the target
resolution of 15". The first data release of the LOFAR LBA Sky Survey covers
650 sqdeg in the HETDEX spring field. The resultant data products released to
the community include mosaic images (I and V Stokes) of the region, and a
catalogue of 42463 detected sources and related Gaussian components used to
describe sources' morphologies. Separate catalogues for 6 in-band frequencies
are also released. The first data release of LoLSS shows that, despite the
influences of the ionosphere, LOFAR can conduct large-scale surveys in the
frequency window 42-66 MHz with unprecedentedly high sensitivity and
resolution. The data can be used to derive unique information on the
low-frequency spectral properties of many thousands of sources with a wide
range of applications in extragalactic and galactic astronomy.Comment: 20 pages, 22 figures, images and catalogues available at
https://www.lofar-surveys.org/lolss.htm
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