662 research outputs found
Management system for building materials as a basis for closed loop material flow analysis considering material efficiency and climate change mitigation
Resource management is becoming increasingly important in the construction sector. In order to support the recycling of materials, it is necessary to determine the quantities in the building stock and those caused by construction activities. At present, a large number of different actors use different categories for construction materials and the raw materials they consist of as well as for waste categories, depending on their field of activity. This results in imprecisions that make it difficult to consistently track and influence mass flows and hinder targeted resource management. This is the starting point of this paper as it discusses possibilities to establish a consistent allocation of materials to context-typical groups following the approach of continuous material flow analysis. On the input-side, aspects of mineral planning and on the output-side aspects of waste and secondary raw material management are being considered and references to grey emissions are established along the entire process chain. In this way, cross-departmental planning relating to recycling management and climate protection will be supported. With regard to the object of consideration and the level of action, a distinction is made between two different spatial scale levels: on the one hand, the individual building level, where the material inventory approach is used to provide detailed information on the building\u27s material composition, and on the other hand the regional level, for which more aggregated information on building material groups is provided in the form of material cadastres. Current results of a research project in Germany are presented
Topoisomer Differentiation of Molecular Knots by FTICR MS: Lessons from Class II Lasso Peptides
Lasso peptides constitute a class of bioactive peptides sharing a knotted
structure where the C-terminal tail of the peptide is threaded through and
trapped within an N-terminalmacrolactamring. The structural characterization of
lasso structures and differentiation from their unthreaded topoisomers is not
trivial and generally requires the use of complementary biochemical and
spectroscopic methods. Here we investigated two antimicrobial peptides
belonging to the class II lasso peptide family and their corresponding
unthreaded topoisomers: microcin J25 (MccJ25), which is known to yield
two-peptide product ions specific of the lasso structure under collisioninduced
dissociation (CID), and capistruin, for which CID does not permit to
unambiguously assign the lasso structure. The two pairs of topoisomers were
analyzed by electrospray ionization Fourier transform ion cyclotron resonance
mass spectrometry (ESI-FTICR MS) upon CID, infrared multiple photon
dissociation (IRMPD), and electron capture dissociation (ECD). CID and
ECDspectra clearly permitted to differentiate MccJ25 from its non-lasso
topoisomer MccJ25-Icm, while for capistruin, only ECD was informative and
showed different extent of hydrogen migration (formation of c\bullet/z from
c/z\bullet) for the threaded and unthreaded topoisomers. The ECD spectra of the
triply-charged MccJ25 and MccJ25-lcm showed a series of radical b-type product
ions {\eth}b0In{\TH}. We proposed that these ions are specific of
cyclic-branched peptides and result from a dual c/z\bullet and y/b
dissociation, in the ring and in the tail, respectively. This work shows the
potentiality of ECD for structural characterization of peptide topoisomers, as
well as the effect of conformation on hydrogen migration subsequent to electron
capture
Test of Lorentz Symmetry by using a 3He/129Xe Co-Magnetometer
To test Lorentz symmetry we used a 3He/129Xe co-magnetometer. We will give a
short summary of our experimental setup and the results of our latest
measurements. We obtained preliminary results for the equatorial component of
the background field interacting with the spin of the bound neutron: b_n < 3.72
x 10^(-32) GeV (95 C.L.).Comment: Presented at the Fifth Meeting on CPT and Lorentz Symmetry,
Bloomington, Indiana, June 28 - July 2, 201
Limit on Lorentz and CPT violation of the bound Neutron Using a Free Precession 3He/129Xe co-magnetometer
We report on the search for Lorentz violating sidereal variations of the
frequency difference of co-located spin-species while the Earth and hence the
laboratory reference frame rotates with respect to a relic background field.
The co-magnetometer used is based on the detection of freely precessing nuclear
spins from polarized 3He and 129Xe gas samples using SQUIDs as low-noise
magnetic flux detectors. As result we can determine the limit for the
equatorial component of the background field interacting with the spin of the
bound neutron to be bn < 3.7 x 10^{-32} GeV (95 C.L.).Comment: 5 pages, 4 figure
Taxonomic corpus-based concept summary generation for document annotation.
Semantic annotation is an enabling technology which links documents to concepts that unambiguously describe their content. Annotation improves access to document contents for both humans and software agents. However, the annotation process is a challenging task as annotators often have to select from thousands of potentially relevant concepts from controlled vocabularies. The best approaches to assist in this task rely on reusing the annotations of an annotated corpus. In the absence of a pre-annotated corpus, alternative approaches suffer due to insufficient descriptive texts for concepts in most vocabularies. In this paper, we propose an unsupervised method for recommending document annotations based on generating node descriptors from an external corpus. We exploit knowledge of the taxonomic structure of a thesaurus to ensure that effective descriptors (concept summaries) are generated for concepts. Our evaluation on recommending annotations show that the content that we generate effectively represents the concepts. Also, our approach outperforms those which rely on information from a thesaurus alone and is comparable with supervised approaches
Bichromatic electromagnetically induced transparency in cold rubidium atoms
In a three-level atomic system coupled by two equal-amplitude laser fields
with a frequency separation 2, a weak probe field exhibits a
multiple-peaked absorption spectrum with a constant peak separation .
The corresponding probe dispersion exhibits steep normal dispersion near the
minimum absorption between the multiple absorption peaks, which leads to
simultaneous slow group velocities for probe photons at multiple frequencies
separated by . We report an experimental study in such a
bichromatically coupled three-level system in cold Rb atoms.
The multiple-peaked probe absorption spectra under various experimental
conditions have been observed and compared with the theoretical calculations.Comment: RevTex, 4 pages, 6 figures, Email address: [email protected]
Electromagnetically induced transparency in multi-level cascade scheme of cold rubidium atoms
We report an experimental investigation of electromagnetically induced
transparency in a multi-level cascade system of cold atoms. The absorption
spectral profiles of the probe light in the multi-level cascade system were
observed in cold Rb-85 atoms confined in a magneto-optical trap, and the
dependence of the spectral profile on the intensity of the coupling laser was
investigated. The experimental measurements agree with the theoretical
calculations based on the density matrix equations of the rubidium cascade
system.Comment: 9 pages, 5 figure
Cross-infection of virulent Dichelobacter nodosus between sheep and co-grazing cattle
AbstractDichelobacter nodosus is the main aetiological agent of ovine footrot and the bacterium has also been associated with interdigital dermatitis is cattle. The aim of this study was to investigate possible cross-infection of virulent D. nodosus between sheep and co-grazing cattle. Five farms, where sheep previously diagnosed with virulent D. nodosus were co-grazing with cattle for different periods of time, were included. The study sample consisted of 200 cows and 50 sheep. All cows were examined for the presence of interdigital dermatitis, and ten ewes, preferably with symptoms of footrot, had the footrot scores recorded. On each farm, the same ten ewes and ten cows were chosen for bacterial analyses. Swabs were analysed for D. nodosus by PCR and culturing. D. nodosus isolates were virulence-tested and assigned to serogroups by fimA variant determination. Biopsies were evaluated histopathologically and analysed by fluorescent in situ hybridization for D. nodosus, Treponema spp. and Fusobacterium necrophorum. D. nodosus defined as virulent by the gelatin gel test were isolated from 16 sheep from four farms and from five cows from two of the same farms. All five cows had interdigital dermatitis. Two of the cows stayed infected for at least eight months. By pulsed-field gel electrophoresis (PFGE), the isolates from the five cows were found to be genetically indistinguishable or closely related to isolates from sheep from the same farm. This indicates that cross-infection between sheep and cows have occurred
Ultra-sensitive magnetometry based on free precession of nuclear spins
We discuss the design and performance of a very sensitive low-field
magnetometer based on the detection of free spin precession of gaseous, nuclear
polarized 3He or 129Xe samples with a SQUID as magnetic flux detector. The
device will be employed to control fluctuating magnetic fields and gradients in
a new experiment searching for a permanent electric dipole moment of the
neutron as well as in a new type of 3He/129Xe clock comparison experiment which
should be sensitive to a sidereal variation of the relative spin precession
frequency. Characteristic spin precession times T_2 of up to 60h could be
measured. In combination with a signal-to-noise ratio of > 5000:1, this leads
to a sensitivity level of deltaB= 1fT after an integration time of 220s and to
deltaB= 10^(-4)fT after one day. Even in that sensitivity range, the
magnetometer performance is statistically limited, and noise sources inherent
to the magnetometer are not limiting. The reason is that free precessing 3He
(129Xe) nuclear spins are almost completely decoupled from the environment.
That makes this type of magnetometer in particular attractive for precision
field measurements where a long-term stability is required
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