22 research outputs found
Beam-Normal Single Spin Asymmetry in Elastic Electron Scattering off Si and Zr
We report on a new measurement of the beam-normal single spin asymmetry
in the elastic scattering of 570 MeV transversely polarized
electrons off Si and Zr at . The
studied kinematics allow for a comprehensive comparison with former results on
C. No significant mass dependence of the beam-normal single spin
asymmetry is observed in the mass regime from C to Zr.Comment: Submitted for publication to Physics Letters
Stability of the human gut virome and effect of gluten-free diet
The human gut microbiome consists of bacteria, archaea, eukaryotes, and viruses. The gut viruses are relatively underexplored. Here, we longitudinally analyzed the gut virome composition in 11 healthy adults: its stability, variation, and the effect of a gluten-free diet. Using viral enrichment and a de novo assembly-based approach, we demonstrate the quantitative dynamics of the gut virome, including dsDNA, ssDNA, dsRNA, and ssRNA viruses. We observe highly divergent individual viral communities, carrying on an average 2,143 viral genomes, 13.1% of which were present at all 3 time points. In contrast to previous reports, the Siphoviridae family dominates over Microviridae in studied individual viromes. We also show individual viromes to be stable at the family level but to vary substantially at the genera and species levels. Finally, we demonstrate that lower initial diversity of the human gut virome leads to a more pronounced effect of the dietary intervention on its composition
Comparison of recoil polarization in the process for protons extracted from and shell
We present first measurements of the double ratio of the polarization
transfer components for knock-out protons from and
shells in measured by the reaction in quasi-elastic kinematics. The data are
compared to theoretical predictions in relativistic distorted-wave impulse
approximation. Our results show that differences between - and -shell
protons, observed when compared at the same initial momentum (missing momentum)
largely disappear when the comparison is done at the same proton virtuality. We
observe no density-dependent medium modifications for protons from and
shells with the same virtuality in spite of the large differences in the
respective nuclear densities
A highly segmented neutron polarimeter for A1
A new neutron polarimeter for measuring the neutron’s electric form factor was designed and constructed to complement the A1 spectrometer setup at the Mainz Microtron (MAMI). The design is based on a previous polarimeter with significant improvements to halve the error of the extracted form factor. A higher granularity of the polarimeter sections and a deeper first section on the one hand, and a faster readout employing Time-over-Threshold methods to measure the signal amplitudes combined with a high-precision FPGA-based TDC on the other hand will allow to achieve this goal. The performance of the new polarimeter during a first measurement campaign in 2019 using liquid hydrogen and deuterium targets will be discussed
ASPECTS OF DEM GENERATION FROM UAS IMAGERY
Since a few years, micro UAS (unmanned aerial systems) with vertical take off and landing capabilities like quadro- or octocopter
are used as sensor platform for Aerophotogrammetry. Since the restricted payload of micro UAS with a total weight up of 5 kg
(payload only up to 1.5 kg), these systems are often equipped with small format cameras. These cameras can be classified as
amateur cameras and it is often the case, that these systems do not meet the requirements of a geometric stable camera for
photogrammetric measurement purposes. However, once equipped with a suitable camera system, an UAS is an interesting
alternative to expensive manned flights for small areas.
The operating flight height of the above described UAS is about 50 up to 150 meters above ground level. This low flight height
lead on the one hand to a very high spatial resolution of the aerial imagery. Depending on the cameras focal length and the sensor's
pixel size, the ground sampling distance (GSD) is usually about 1 up to 5 cm. This high resolution is useful especially for the
automatic generation of homologous tie-points, which are a precondition for the image alignment (bundle block adjustment).
On the other hand, the image scale depends on the object's height and the UAV operating height. Objects like mine heaps or
construction sites show high variations of the object's height. As a result, operating the UAS with a constant flying height will lead
to high variations in the image scale. For some processing approaches this will lead to problems e.g. the automatic tie-point
generation in stereo image pairs.
As precondition to all DEM generating approaches, first of all a geometric stable camera, sharp images are essentially. Well known
calibration parameters are necessary for the bundle adjustment, to control the exterior orientations. It can be shown, that a
simultaneous on site camera calibration may lead to misaligned aerial images. Also, the success rate of an automatic tie-point
generation differs extremely between several photogrammetric software packages.
In this article, the calibration results of a suitable camera system will be shown. For a small format consumer grade camera, the
authors will give the proof of ability for photogrammetric measurements purposes. This includes the results of different processing
approaches for DEM generation of environments showing high object height variations
PHOTOGRAMMETRY AND REMOTE SENSING: NEW GERMAN STANDARDS (DIN) SETTING QUALITY REQUIREMENTS OF PRODUCTS GENERATED BY DIGITAL CAMERAS, PAN-SHARPENING AND CLASSIFICATION
10 years after the first introduction of a digital airborne mapping camera in the ISPRS conference 2000 in Amsterdam, several digital
cameras are now available. They are well established in the market and have replaced the analogue camera. A general improvement
in image quality accompanied the digital camera development. The signal-to-noise ratio and the dynamic range are significantly
better than with the analogue cameras. In addition, digital cameras can be spectrally and radiometrically calibrated.
The use of these cameras required a rethinking in many places though. New data products were introduced. In the recent years, some
activities took place that should lead to a better understanding of the cameras and the data produced by these cameras. Several
projects, like the projects of the German Society for Photogrammetry, Remote Sensing and Geoinformation (DGPF) or EuroSDR
(European Spatial Data Research), were conducted to test and compare the performance of the different cameras.
In this paper the current DIN (Deutsches Institut fuer Normung - German Institute for Standardization) standards will be presented.
These include the standard for digital cameras, the standard for ortho rectification, the standard for classification, and the standard for
pan-sharpening. In addition, standards for the derivation of elevation models, the use of Radar / SAR, and image quality are in
preparation.
The OGC has indicated its interest in participating that development. The OGC has already published specifications in the field of
photogrammetry and remote sensing. One goal of joint future work could be to merge these formerly independent developments and
the joint development of a suite of implementation specifications for photogrammetry and remote sensing
Stability of the human gut virome and effect of gluten-free diet
The human gut microbiome consists of bacteria, archaea, eukaryotes, and viruses. The gut viruses are relatively underexplored. Here, we longitudinally analyzed the gut virome composition in 11 healthy adults: its stability, variation, and the effect of a gluten-free diet. Using viral enrichment and a de novo assembly-based approach, we demonstrate the quantitative dynamics of the gut virome, including dsDNA, ssDNA, dsRNA, and ssRNA viruses. We observe highly divergent individual viral communities, carrying on an average 2,143 viral genomes, 13.1% of which were present at all 3 time points. In contrast to previous reports, the Siphoviridae family dominates over Microviridae in studied individual viromes. We also show individual viromes to be stable at the family level but to vary substantially at the genera and species levels. Finally, we demonstrate that lower initial diversity of the human gut virome leads to a more pronounced effect of the dietary intervention on its composition
A highly segmented neutron polarimeter for A1
International audienceA new neutron polarimeter for measuring the neutron’s electric form factor was designed and constructed to complement the A1 spectrometer setup at the Mainz Microtron (MAMI). The design is based on a previous polarimeter with significant improvements to halve the error of the extracted form factor. A higher granularity of the polarimeter sections and a deeper first section on the one hand, and a faster readout employing Time-over-Threshold methods to measure the signal amplitudes combined with a high-precision FPGA-based TDC on the other hand will allow to achieve this goal. The performance of the new polarimeter during a first measurement campaign in 2019 using liquid hydrogen and deuterium targets will be discussed