TRPV4 is the temperature-sensitive ion channel of human sperm.

Ion channels control the ability of human sperm to fertilize the egg by triggering hyperactivated motility, which is regulated by membrane potential, intracellular pH, and cytosolic calcium. Previous studies unraveled three essential ion channels that regulate these parameters: (1) the Ca2+ channel CatSper, (2) the K+ channel KSper, and (3) the H+ channel Hv1. However, the molecular identity of the sperm Na+ conductance that mediates initial membrane depolarization and, thus, triggers downstream signaling events is yet to be defined. Here, we functionally characterize DSper, the Depolarizing Channel of Sperm, as the temperature-activated channel TRPV4. It is functionally expressed at both mRNA and protein levels, while other temperature-sensitive TRPV channels are not functional in human sperm. DSper currents are activated by warm temperatures and mediate cation conductance, that shares a pharmacological profile reminiscent of TRPV4. Together, these results suggest that TRPV4 activation triggers initial membrane depolarization, facilitating both CatSper and Hv1 gating and, consequently, sperm hyperactivation

The effect of thermal-mechanical processing of the exfoliation corrosion resistance of an aluminum-zinc-magnesium-copper alloy

The objective of this investigation was to evaluate the effect of thermal-mechanical processing on the exfoliation corrosion resistance of an aluminum-zinc-magnesium-copper alloy. the aluminum alloy used was commercially available 7178 alloy in two thicknesses, 0.390 inch thick and 0.250 inch thick. this material was reduced 10, 25 and 40% in thickness in both the annealed and solution heat treated conditions. The material was then aged to a high strength condition, T6, or T8, in the case of the material reduced in the solution heat treated condition. The effect of the thermal-mechanical processing on the exfoliation corrosion resistance was then evaluated by exposing 3 by 6 inch specimens to both an intermittent acidified salt spray test and a salt spray plus sulfur dioxide gas test. Increasing amounts of mechanical deformation of material in the solution heat treated condition resulted in progressively lower resistance to exfoliation corrosion. As the amount of deformation of the annealed material increased to a point where recrystallization resulted during the subsequent solution heat treatment, the exfoliation corrosion resistance improved. The aging schedules developed for the T8 condition resulted in strengths equivalent to the high strength T6 condition without significant losses in ductility. It was also demonstrated that the salt spray plus sulfur dioxide test was a considerably more severe exfoliation test environment than the intermittent acidified salt spray test --Abstract, page ii

Die Wahl 2006, die Linke und der jähe Bedarf an Gespenstern…

Inhalt Eine Wahl ohne Wahl – Grundmerkmale der Wahlauseinandersetzung 2006 Warum die Linke 2006 scheinbar alles nur falsch machen kann Wozu eigentlich noch wählen? Die Delegitimierung der Politik und ihre Ursachen Worum geht es eigentlich? Der »Lagerwahlkampf« und das Argument der »verlorenen Stimme« Der Mensch als Kostenfaktor: Die Erosion des Politikfelds Sozialpolitik Getrennt marschieren, vereint schlagen? PDS und WASG und das wahltechnische Problem Dem Nein eine Stimme: Handlungsoptionen für die Linke Vom Schatten zum Gespenst »Die Gesellschaft findet sich plötzlich in einen Zustand momentaner Barbarei zurückversetzt ... die Industrie, der Handel scheinen vernichtet, und warum? Weil sie zu viel Zivilisation, zu viel Lebensmittel, zu viel Industrie, zu viel Handel besitzt ... Wodurch überwindet die Bourgeoisie die Krisen? Einerseits durch die erzwungene Vernichtung einer Masse von Produktivkräften; andererseits durch die Eroberung neuer Märkte und die gründlichere Ausbeutung alter Märkte. Wodurch also? Dadurch, dass sie allseitigere und gewaltigere Krisen vorbereitet und die Mittel, den Krisen vorzubeugen, vermindert.« Dieser Befund, aus dem Kommunistischen Manifest von 1848, liest sich wie eine unmittelbare Zustandsbeschreibung der gesellschaftlichen Verhältnisse im heutigen fortgeschrittenen Neoliberalismus. Das Manifest muss auch zur regelmäßigen Lektüre der Hartz-Kommission gehört haben; am Ende des angeblichen Jahrhundert-Reformwerks werden die im Manifest beschriebenen Verhältnisse des totalen Arbeitsmarkts stehen: »Die Arbeiter, die sich stückweis verkaufen müssen, sind eine Ware wie jeder andere Handelsartikel und daher gleichmäßig allen Wechselfällen der Konkurrenz, allen Schwankungen des Marktes ausgesetzt ... In demselben Maße, in dem die Widerwärtigkeit der Arbeit wächst, nimmt daher der Lohn ab.« Was fehlt, ist das Gespenst

Automatic source localization and spectra generation from sparse beamforming maps

Beamforming is an imaging tool for the investigation of aeroacoustic phenomena and results in high dimensional data that is broken down to spectra by integrating spatial Regions Of Interest. This paper presents two methods that enable the automated identification of aeroacoustic sources in sparse beamforming maps and the extraction of their corresponding spectra to overcome the manual definition of Regions Of Interest. The methods are evaluated on two scaled airframe half-model wind-tunnel measurements and on a generic monopole source. The first relies on the spatial normal distribution of aeroacoustic broadband sources in sparse beamforming maps. The second uses hierarchical clustering methods. Both methods are robust to statistical noise and predict the existence, location, and spatial probability estimation for sources based on which Regions Of Interest are automatically determined.Comment: Preprint for JASA special issue on machine learning in acoustics, Revision

Hierarchische Modelle für das visuelle Erkennen und Lernen von Objekten, Szenen und Aktivitäten

In many computer vision applications, objects have to be learned and recognized in images or image sequences. Most of these objects have a hierarchical structure.For example, 3d objects can be decomposed into object parts, and object parts, in turn, into geometric primitives. Furthermore, scenes are composed of objects. And also activities or behaviors can be divided hierarchically into actions, these into individual movements, etc. Hierarchical models are therefore ideally suited for the representation of a wide range of objects used in applications such as object recognition, human pose estimation, or activity recognition. In this work new probabilistic hierarchical models are presented that allow an efficient representation of multiple objects of different categories, scales, rotations, and views. The idea is to exploit similarities between objects, object parts or actions and movements in order to share calculations and avoid redundant information. We will introduce online and offline learning methods, which enable to create efficient hierarchies based on small or large training datasets, in which poses or articulated structures are given by instances. Furthermore, we present inference approaches for fast and robust detection. These new approaches combine the idea of compositional and similarity hierarchies and overcome limitations of previous methods. They will be used in an unified hierarchical framework spatially for object recognition as well as spatiotemporally for activity recognition. The unified generic hierarchical framework allows us to apply the proposed models in different projects. Besides classical object recognition it is used for detection of human poses in a project for gait analysis. The activity detection is used in a project for the design of environments for ageing, to identify activities and behavior patterns in smart homes. In a project for parking spot detection using an intelligent vehicle, the proposed approaches are used to hierarchically model the environment of the vehicle for an efficient and robust interpretation of the scene in real-time.In zahlreichen Computer Vision Anwendungen müssen Objekte in einzelnen Bildern oder Bildsequenzen erlernt und erkannt werden. Viele dieser Objekte sind hierarchisch aufgebaut.So lassen sich 3d Objekte in Objektteile zerlegen und Objektteile wiederum in geometrische Grundkörper. Und auch Aktivitäten oder Verhaltensmuster lassen sich hierarchisch in einzelne Aktionen aufteilen, diese wiederum in einzelne Bewegungen usw. Für die Repräsentation sind hierarchische Modelle dementsprechend gut geeignet. In dieser Arbeit werden neue probabilistische hierarchische Modelle vorgestellt, die es ermöglichen auch mehrere Objekte verschiedener Kategorien, Skalierungen, Rotationen und aus verschiedenen Blickrichtungen effizient zu repräsentieren. Eine Idee ist hierbei, Ähnlichkeiten unter Objekten, Objektteilen oder auch Aktionen und Bewegungen zu nutzen, um redundante Informationen und Mehrfachberechnungen zu vermeiden. In der Arbeit werden online und offline Lernverfahren vorgestellt, die es ermöglichen, effiziente Hierarchien auf Basis von kleinen oder großen Trainingsdatensätzen zu erstellen, in denen Posen und bewegliche Strukturen durch Beispiele gegeben sind. Des Weiteren werden Inferenzansätze zur schnellen und robusten Detektion vorgestellt. Diese werden innerhalb eines einheitlichen hierarchischen Frameworks sowohl räumlich zur Objekterkennung als auch raumzeitlich zur Aktivitätenerkennung verwendet. Das einheitliche Framework ermöglicht die Anwendung des vorgestellten Modells innerhalb verschiedener Projekte. Neben der klassischen Objekterkennung wird es zur Erkennung von menschlichen Posen in einem Projekt zur Ganganalyse verwendet. Die Aktivitätenerkennung wird in einem Projekt zur Gestaltung altersgerechter Lebenswelten genutzt, um in intelligenten Wohnräumen Aktivitäten und Verhaltensmuster von Bewohnern zu erkennen. Im Rahmen eines Projektes zur Parklückenvermessung mithilfe eines intelligenten Fahrzeuges werden die vorgestellten Ansätze verwendet, um das Umfeld des Fahrzeuges hierarchisch zu modellieren und dadurch das Szenenverstehen zu ermöglichen

Weighted Data Spaces for Correlation-Based Array Imaging in Experimental Aeroacoustics

This article discusses aeroacoustic imaging methods based on correlation measurements in the frequency domain. Standard methods in this field assume that the estimated correlation matrix is superimposed with additive white noise. In this paper we present a mathematical model for the measurement process covering arbitrarily correlated noise. The covariance matrix of correlation data is given in terms of fourth order moments. The aim of this paper is to explore the use of such additional information on the measurement data in imaging methods. For this purpose a class of weighted data spaces is introduced, where each data space naturally defines an associated beamforming method with a corresponding point spread function. This generic class of beamformers contains many well-known methods such as Conventional Beamforming, (Robust) Adaptive Beamforming or beamforming with shading. This article examines in particular weightings that depend on the noise (co)variances. In a theoretical analysis we prove that the beamformer, weighted by the full noise covariance matrix, has minimal variance among all beamformers from the described class. Application of the (co)variance weighted methods on synthetic and experimental data show that the resolution of the results is improved and noise effects are reduced.Comment: Preprint subitted to "Journal of Sound and Vibration

Experimental demonstration of the stability of Berry's phase for a spin-1/2 particle

The geometric phase has been proposed as a candidate for noise resilient coherent manipulation of fragile quantum systems. Since it is determined only by the path of the quantum state, the presence of noise fluctuations affects the geometric phase in a different way than the dynamical phase. We have experimentally tested the robustness of Berry's geometric phase for spin-1/2 particles in a cyclically varying magnetic field. Using trapped polarized ultra-cold neutrons it is demonstrated that the geometric phase contributions to dephasing due to adiabatic field fluctuations vanish for long evolution times.Comment: 4 pages, 4 figure