Coding Efficiency of Fly Motion Processing Is Set by Firing Rate, Not Firing Precision

To comprehend the principles underlying sensory information processing, it is important to understand how the nervous system deals with various sources of perturbation. Here, we analyze how the representation of motion information in the fly's nervous system changes with temperature and luminance. Although these two environmental variables have a considerable impact on the fly's nervous system, they do not impede the fly to behave suitably over a wide range of conditions. We recorded responses from a motion-sensitive neuron, the H1-cell, to a time-varying stimulus at many different combinations of temperature and luminance. We found that the mean firing rate, but not firing precision, changes with temperature, while both were affected by mean luminance. Because we also found that information rate and coding efficiency are mainly set by the mean firing rate, our results suggest that, in the face of environmental perturbations, the coding efficiency is improved by an increase in the mean firing rate, rather than by an increased firing precision

Neutrophil depletion reduces edema formation and tissue loss following traumatic brain injury in mice

Background: Brain edema as a result of secondary injury following traumatic brain injury (TBI) is a major clinical concern. Neutrophils are known to cause increased vascular permeability leading to edema formation in peripheral tissue, but their role in the pathology following TBI remains unclear. Methods: In this study we used controlled cortical impact (CCI) as a model for TBI and investigated the role of neutrophils in the response to injury. The outcome of mice that were depleted of neutrophils using an anti-Gr-1 antibody was compared to that in mice with intact neutrophil count. The effect of neutrophil depletion on blood-brain barrier function was assessed by Evan's blue dye extravasation, and analysis of brain water content was used as a measurement of brain edema formation (24 and 48 hours after CCI). Lesion volume was measured 7 and 14 days after CCI. Immunohistochemistry was used to assess cell death, using a marker for cleaved caspase-3 at 24 hours after injury, and microglial/macrophage activation 7 days after CCI. Data were analyzed using Mann-Whitney test for non-parametric data. Results: Neutrophil depletion did not significantly affect Evan's blue extravasation at any time-point after CCI. However, neutrophil-depleted mice exhibited a decreased water content both at 24 and 48 hours after CCI indicating reduced edema formation. Furthermore, brain tissue loss was attenuated in neutropenic mice at 7 and 14 days after injury. Additionally, these mice had a significantly reduced number of activated microglia/macrophages 7 days after CCI, and of cleaved caspase-3 positive cells 24 h after injury. Conclusion: Our results suggest that neutrophils are involved in the edema formation, but not the extravasation of large proteins, as well as contributing to cell death and tissue loss following TBI in mice

Entwicklung eines 600 GHz-Empfaengers Schlussbericht

Receivers with cryogenic Schottky-mixers have been developed in the framework of a technology program for the ESA satellite project FIRST and the american - german airborne observatory project SOFIA. Three receivers have been built for the frequency ranges 330-345 GHz, 460/492 GHz and 660 GHz. The achieved DSB-receiver noise temperatures are 350 K (330-345 GHz), 550 K (460/492 GHz) and around 5000 K (660 GHz, uncooled). Especially the results of the first two receivers are internationally the best values for cryogenic Schottky-receivers. However, in the meantime better results have been achieved with superconducting (SIS) mixers, with the disadvantage of more complicated cryosystems (cryogenic cooling to 4 K instead of 20 K for Schottky-mixers). In the framework of the project, quasi-optic components, Gunn-oscillators and frequency multipliers have been developed. The combination Gunn-oscillator -multiplier generates the necessary pump power to drive the mixers. This type of pump sources is appropriate for space applications, because they are very compact and have a low power consumption. (orig.)Im Rahmen der Vorentwicklung fuer das Satelliten-Projekt FIRST (ESA) und dem amerikanisch-deutschen Flugzeugprojekt SOFIA wurden Empfaenger mit gekuehlten Schottky-Mischern entwickelt. Es wurden insgesamt drei Empfaenger aufgebaut und zwar fuer den Frequenzbereich 330-345 GHz, 460/492 GHz und 660 GHz. Die erreichten DSB-Empfaengerrauschtemperaturen liegen bei 350 K (330-345 GHz), 550 K (460/492 GHz) und um 5000 K (660 GHz, ungekuehlt). Insbesondere die Werte fuer die ersten beiden Empfaenger sind die international besten fuer gekuehlte Schottky-Empfaenger. Mit supraleitenden (SIS) Mischern werden jedoch inzwischen bessere Rauschwerte erreicht, allerdings mit dem Nachteil eines groesseren Aufwandes fuer die Kuehltechnik (Kuehlung auf ca. 4 K gegenueber 20 K bei Schottky-Mischern). Im Rahmen des Projektes wurden weiterhin quasi-optische Komponenten, Gunn-Oszillatoren und Frequenzvervielfacher entwickelt. Die Kombination Gunn-Oszillator-Frequenzvervielfacher liefert die erforderliche Pumpleistung fuer den Betrieb der Schottky-Mischer. Insbesondere bei Raumfahrtanwendungen sind diese Art von Pumpquellen sehr geeignet, da sie sehr kompakt sind und einem geringen elektrischen Leistungsbedarf haben. (orig.)SIGLEAvailable from TIB Hannover: F96B203+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany); Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA) GmbH, Bonn (Germany)DEGerman

NEW MILLIMETER-WAVE INTRACAVITY JET SPECTROMETER BASED ON OROTRON

Author Institution: Institute of Spectroscopy, Russian Academy of Sciences; I. Physical Institute, University of CologneA new highly sensitive millimeter-wave spectrometer has been developed for the investigation of weakly bounded van der Waals molecular complexes produced in a supersonic jet expansion. The main feature of the spectrometer is that the molecular jet expands into the high quality $(Q = 10^{4})$ resonator of a tunable coherent source of radiation - OROTRON (106- 150 GHz). The absorption of the radiation inside the cavity is detected by the variation of the electron current of the orotron in a collector circuit. This simple method of detection and the narrow linewidth of the orotron radiation (10-15 kHz) without any frequency and phase stabilization make this spectrometer very simple and convenient for searching of new lines and for recording of weak spectra. The large effective length of absorption results in an improvement of sensitivity for more than two orders of magnitude in comparison with the existing single path schemes. The new set-up has been adjusted and tested by the observation of the isotopomers of CO in natural abundance. The rotational transition $J = 1 - 0$ of isotopic species $^{13}C^{17}O (0.000\%)$ with partially resolved quadrupole structure was observed. The measurements of the $K = 1 - 0$ high-J $(10<J<20)$ pure rotational transitions of Ar-CO and the first observation of Ne-CO (for${^{20.21,22}}Ne$ isotopes in natural abundance) in millimeter-wave range have been made. The analysis of these data will be presented

Phantom-Based Evaluation of a Planar Microwave Sensor for Non-Invasive Intracranial Pressure Monitoring

Intracranial pressure (ICP) measurements are essential to improve current clinical decision schemes in different scenarios: hospital, home, sports field, military field, etc. ICP is fundamental for understanding cerebrospinal fluid (CSF) mechanics and modelling better physiological conditions. Nowadays, several studies have focused on developing non-invasive ICP monitoring methods (nICP) based on different sensing modalities with advantages and disadvantages. Some works have focused on microwave-based sensing; among them is the application of NASA SansEC spectroscopy technology. This work extends previous results on this technology to nICP. Notably, in a simple phantom-based experiment and with a square spiral planar resonator sensor, pressure values up to 48 mmHg could be achievable. The phantom-based experiment consists of a large column tank gradually filled with a liquid that mimics the cerebrospinal fluid (CSF) based on data from the Italian database IFAC. Microwave-based methods for non-invasive intracranial pressure monitoring could be instrumental as tools that can be easily embedded and worn and give indications of brain health to trigger proper care in the future

Millimeter and submillimeter wave spectroscopy of higher energy conformers of 1,2-propanediol

We have performed a study of the millimeter/submillimeter wave spectrum of four higher energy conformers of 1,2-propanediol. The present analysis of rotational transitions carried out in the frequency range 38-400 GHz represents a significant extension of previous microwave work. The new data were combined with previously-measured microwave transitions and fitted using a Watson's S-reduced Hamiltonian. The final fits were within experimental accuracy, and included spectroscopic parameters up to sixth order of angular momentum, for the ground states of the four higher energy conformers following previously studied ones: gGa, gG'g', aGg' and g'Gg. The present analysis provides reliable frequency predictions for astrophysical detection of 1,2-propanediol by radio telescope arrays at millimeter wavelengths. (C) 2017 Elsevier Inc. All rights reserved

Laboratory spectroscopy of 1, 2-propanediol at millimeter and submillimeter wavelengths

Context. Ethanediol is one of the largest complex organic molecules detected in space thus far. It has been found in different types of molecular clouds. The two propanediol isomers are the next larger diols. Hence, they are viable candidates to be searched for in space. Aims. We wish to provide sufficiently large and accurate sets of spectroscopic parameters of 1, 2-propanediol to facilitate searches for this molecule at millimeter and longer submillimeter wavelengths. Methods. We recorded rotational spectra of 1, 2-propanediol in three wide frequency windows between 38 and 400 GHz. Results. We made extensive assignments for the three lowest energy conformers to yield spectroscopic parameters up to eighth order of angular momentum. Conclusions. Our present data will be helpful for identifying 1, 2-propanediol at moderate submillimeter or longer wavelengths with radio telescope arrays such as ALMA, NOEMA, or EVLA. In particular, its detection with ALMA in sources, in which ethanediol was detected, appears to be promising