3,575 research outputs found
On an optimality property of ternary trees
The concept of effort is defined for rooted trees. The class of rooted trees with minimal effort is determined. The asymptotic behaviour of the minimal effort is calculated. Various choices for the effort function are considered, as well as variations of the optimality criterion
A Gas Generating System for Complex Gas Mixtures – Multifunctional Application in PTR Method Optimization and Downstream Methanol Synthesis
The multifunctional applicability of a gas mixing system is presented within the scope of Carbon2Chem® for the simulation of steel mill flue gases and their application in downstream processes. A special focus is set on the parallel operation of the gas mixing system to enable PTR-MS method optimization and methanol synthesis with simulated real gas matrices. Information is gathered for the design of downstream processes and their application, where methanol synthesis is chosen as a model reaction. A proof-of-principle study is presented where operation of a catalytic reactor setup in combination with the gas mixing system and a compressor generate reproducible results. The addition of potential trace components in methanol synthesis is exemplarily demonstrated using ammonia. With respect to the PTR-MS application, the dosing of two calibration gas standards, toluene and carbonyl sulfide, via the gas mixing system were analyzed in detail. The obtained results give insight into its applicability to simulate traces and enables the further development of analytical methods for the analysis of trace impurities in the ppb and ppt range in complex gas mixtures
Influence of Axial Workpiece Positioning during Magnetic Pulse Welding of Aluminum-Steel Joints
Magnetic Pulse Welding (MPW) offers a method to economically join similar and dissimilar
metals without the need for external physical or chemical binders, while avoiding the
adverse heating effects seen in many welding techniques. MPW allows for the fabrication
of joints via the harnessing of Lorentz forces, which result from discharging a current
pulse through a coil. In the process an outer piece (flyer) is accelerated onto an inner
piece (parent), and welding is achieved using propagating impact fronts. There are
several geometrical factors to be considered including the flyer-coil distance, the parentflyer
distance, as well as the axial relationship between flyer and coil (working length).
Various shapes of the front are possible and each configuration has its own advantages
and drawbacks. The goal of this work is to show not only how the aforementioned
parameters are related, but also ways to optimize front propagations, which are vital to the
welding result. This is done primarily by determining the influence of the working length of
tubular MPW specimens. It is shown that for steel-aluminum joints in the given
arrangements, three different front regimes exist, which are related to geometrical factors.
These results are especially useful to avoid seemingly favorable but nevertheless
suboptimal conditions for flyer movement that would reduce weld quality and energy
efficiency of the process
The Turkey Ig-like receptor family: identification, expression and function.
The chicken leukocyte receptor complex located on microchromosome 31 encodes the chicken Ig-like receptors (CHIR), a vastly expanded gene family which can be further divided into three subgroups: activating CHIR-A, bifunctional CHIR-AB and inhibitory CHIR-B. Here, we investigated the presence of CHIR homologues in other bird species. The available genome databases of turkey, duck and zebra finch were screened with different strategies including BLAST searches employing various CHIR sequences, and keyword searches. We could not identify CHIR homologues in the distantly related zebra finch and duck, however, several partial and complete sequences of CHIR homologues were identified on chromosome 3 of the turkey genome. They were designated as turkey Ig-like receptors (TILR). Using cDNA derived from turkey blood and spleen RNA, six full length TILR could be amplified and further divided according to the typical sequence features into one activating TILR-A, one inhibitory TILR-B and four bifunctional TILR-AB. Since the TILR-AB sequences all displayed the critical residues shown to be involved in binding to IgY, we next confirmed the IgY binding using a soluble TILR-AB1-huIg fusion protein. This fusion protein reacted with IgY derived from various gallinaceous birds, but not with IgY from other bird species. Finally, we tested various mab directed against CHIR for their crossreactivity with either turkey or duck leukocytes. Whereas no staining was detectable with duck cells, the CHIR-AB1 specific mab 8D12 and the CHIR-A2 specific mab 13E2 both reacted with a leukocyte subpopulation that was further identified as thrombocytes by double immunofluorescence employing B-cell, T-cell and thrombocyte specific reagents. In summary, although the turkey harbors similar LRC genes as the chicken, their distribution seems to be distinct with predominance on thrombocytes rather than lymphocytes
The InMAS Approach
The Internet Malware Analysis System (InMAS) is a modular platform for distributed, large-scale monitoring of malware on the Internet. InMAS integrates diverse tools for malware collection (using honeypots)
and malware analysis (mainly using dynamic analysis). All collected information is aggregated and accessible through an intuitive and easy-to-use web interface. In this paper, we provide an overview of the structure of InMAS and the various tools it integrates. We also introduce the web frontend that displays all information on different levels of abstraction, from a coarse-grained overview down to highly detailed information on demand
Botulinum toxin type A in the prophylactic treatment of chronic tension-type headache: A multicentre, double-blind, randomized, placebo-controlled, parallel-group study
We studied the safety and efficacy of 0 U, 50 U, 100 U, 150 U (five sites), 86 Usub and 100 Usub (three sites) botulinum toxin type A (BoNTA; BOTOX); Allergan, Inc., Irvine, CA, USA) for the prophylaxis of chronic tension-type headache (CTTH). Three hundred patients (62.3% female; mean age 42.6 years) enrolled. For the primary endpoint, the mean change from baseline in the number of TTH-free days per month, there was no statistically significant difference between placebo and four BoNTA groups, but a significant difference favouring placebo vs. BoNTA 150 was observed (4.5 vs. 2.8 tension headache-free days/month; P = 0.007). All treatment groups improved at day 60. Although efficacy was not demonstrated for the primary endpoint, at day 90, more patients in three BoNTA groups had \u3eor=50% decrease in tension headache days than did placebo (
The Ni(n,) cross section measured with DANCE
The neutron capture cross section of the s-process branch nucleus Ni
affects the abundances of other nuclei in its region, especially Cu and
Zn. In order to determine the energy dependent neutron capture cross
section in the astrophysical energy region, an experiment at the Los Alamos
National Laboratory has been performed using the calorimetric 4 BaF
array DANCE. The (n,) cross section of Ni has been determined
relative to the well known Au standard with uncertainties below 15%.
Various Ni resonances have been identified based on the Q-value.
Furthermore, the s-process sensitivity of the new values was analyzed with the
new network calculation tool NETZ.Comment: 11 pages, 13 page
Electron-phonon renormalization of the absorption edge of the cuprous halides
Compared to most tetrahedral semiconductors, the temperature dependence of
the absorption edges of the cuprous halides (CuCl, CuBr, CuI) is very small.
CuCl and CuBr show a small increase of the gap with increasing
temperature, with a change in the slope of vs. at around 150 K: above
this temperature, the variation of with becomes even smaller. This
unusual behavior has been clarified for CuCl by measurements of the low
temperature gap vs. the isotopic masses of both constituents, yielding an
anomalous negative shift with increasing copper mass. Here we report the
isotope effects of Cu and Br on the gap of CuBr, and that of Cu on the gap of
CuI. The measured isotope effects allow us to understand the corresponding
temperature dependences, which we also report, to our knowledge for the first
time, in the case of CuI. These results enable us to develop a more
quantitative understanding of the phenomena mentioned for the three halides,
and to interpret other anomalies reported for the temperature dependence of the
absorption gap in copper and silver chalcogenides; similarities to the behavior
observed for the copper chalcopyrites are also pointed out.Comment: 14 pages, 5 figures, submitted to Phys. Rev.
Infection by a foliar endophyte elicits novel arabidopside-based plant defence reactions in its host, Cirsium arvense
Endophytic fungi live asymptomatically within plants. They are usually regarded as non-pathogenic or even mutualistic, but whether plants respond antagonistically to their presence remains unclear, particularly in the little-studied associations between endophytes and nong-raminoid herbaceous plants.
We investigated the effects of the endophyte Chaetomium cochlioides on leaf chemistry in Cirsium arvense. Plants were sprayed with spores; leaf material from both subsequent new growth and the sprayed leaves was analysed 2 wk later. Infection frequency was 91% and63% for sprayed and new growth, respectively, indicating that C. cochlioides rapidly infects new foliage.
Metabolomic analyses revealed marked changes in leaf chemistry with infection, especially in new growth. Changes in several novel oxylipin metabolites were detected, including arabi-dopsides reported here for the first time in a plant species other than Arabidopsis thaliana,and a jasmonate-containing galactolipid.
The production of these metabolites in response to endophyte presence, particularly in newly infected foliage, suggests that endophytes elicit similar chemical responses in plants to those usually produced following wounding, herbivory and pathogen invasion. Whether en-dophytes benefit their hosts may depend on a complex series of chemically mediated interactions between the plant, the endophyte, other microbial colonists and natural enemies
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