Application of a quasi-open ion source for neutral particle density measurements in the thermosphere

Open ion source mass spectrometer used with omegatron mass spectrometer to measure atmospheric gas density and composition in thermosphere probe experimen

Exploring the functional domain and the target of the tetanus toxin light chain in neurohypophysial terminals

The tetanus toxin light chain blocks calcium induced vasopressin release from neurohypophysial nerve terminals. Here we show that histidine residue 233 within the putative zinc binding motif of the tetanus toxin light chain is essential for the inhibition of exocytosis, in the rat. The zinc chelating agent dipicolinic acid as well as captopril, an inhibitor of zinc-dependent peptidases, counteract the effect of the neurotoxin. Synthetic peptides, the sequences of which correspond to motifs present in the cytoplasmic domain of the synaptic vesicle membrane protein synaptobrevin 1 and 2, prevent the effect of the tetanus toxin light chain. Our results indicate that zinc bound to the zinc binding motif constitutes the active site of the tetanus toxin light chain. Moreover they suggest that cleavage of synaptobrevin by the neurotoxin causes the inhibition of exocytotic release of vasopressin from secretory granules

Fluctuations of 1/f1/f noise and the low frequency cutoff paradox

Recent experiments on blinking quantum dots and weak turbulence in liquid crystals reveal the fundamental connection between $1/f$ noise and power law intermittency. The non-stationarity of the process implies that the power spectrum is random -- a manifestation of weak ergodicity breaking. Here we obtain the universal distribution of the power spectrum, which can be used to identify intermittency as the source of the noise. We solve an outstanding paradox on the non integrability of $1/f$ noise and the violation of Parseval's theorem. We explain why there is no physical low frequency cutoff and therefore cannot be found in experiments.Comment: 5 pages, 2 figures, supplementary material (4 pages

Desulfuromonas svalbardensis sp nov and Desulfuromusa ferrireducens sp nov., psychrophilic, Fe(III)-reducing bacteria isolated from Arctic sediments, Svalbard

Two psychrophilic, Gram-negative, rod-shaped, motile bacteria (strains 112T and 102T) that conserved energy from dissimilatory Fe(III) reduction concomitant with acetate oxidation were isolated from permanently cold Arctic marine sediments. Both strains grew at temperatures down to -2 degrees C, with respective temperature optima of 14 degrees C and 14-17 degrees C for strains 112T and 102T. The isolated strains reduced Fe(III) using common fermentation products such as acetate, lactate, propionate, formate or hydrogen as electron donors, and they also grew with fumarate as the sole substrate. As alternatives to Fe(III), they reduced fumarate, S0 and Mn(IV). Based on 16S rRNA gene sequence similarity, strain 112T was most closely related to Desulfuromonas acetoxidans (97.0 %) and Desulfuromonas thiophila NZ27T (95.5 %), and strain 102T to Malonomonas rubra Gra Mal 1T (96.3 %) and Desulfuromusa succinoxidans GylacT (95.9 %) within the Deltaproteobacteria. Strains 112T and 102T therefore represent novel species, for which the names Desulfuromonas svalbardensis sp. nov. (type strain 112T=DSM 16958T=JCM 12927T) and Desulfuromusa ferrireducens sp. nov. (type strain 102T=DSM 16956T=JCM 12926T) are proposed

Effects of different deep freezing and thawing procedures on the developmental capacity of bovine embryos

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Off-axis reflection zone plate for quantitative soft x-ray source characterization

A compact system for high-resolution spectroscopy and quantitative photon flux and brilliance measurements of pulsed soft x-ray sources is described. The calibrated system combines a novel elliptical off-axis reflection zone plate with charge-coupled device detection for simultaneous spectral and spatial measurements. Experiments on a water-window droplet-target laser-plasma source demonstrate lambda/Delta lambda greater than or equal to 1000 spectral resolution and absolute flux and brilliance measurements. (C) 1997 American Institute of Physics

Pitch determination considering laryngealization effects in spoken dialogs

A frequent phenomenon in spoken dialogs of the information seeking type are short elliptic utterances whose mood (declarative or interrogative) can only be distinguished by intonation. The main acoustic evidence is conveyed by the fundamental frequency or Fo-contour. Many algorithms for Fo determination have been reported in the literature. A common problem are irregularities of speech known as "laryngealizations". This article describes an approach based on neural network techniques for the improved determination of fundamental frequency. First, an improved version of our neural network algorithm for reconstruction of the voice source signal (glottis signal) is presented. Second, the reconstructed voice source signal is used as input to another neural network distinguishing the three classes "voiceless", "voiced non-laryngealized", and "voiced laryngealized". Third, the results are used to improve an existing Fo algorithm. Results of this approach are presented and discussed in the context of the application in a spoken dialog system

Diurnal survey of the thermosphere Final report

Nike-Tomahawk launched soundings over Cape Kennedy to study composition and diurnal variations of thermospher