1,306 research outputs found

    Die Anfänge der Eisenverhüttung im Bereich der Przeworsk-Kultur

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    Technische Innovationen wie die Eisenverhüttung bedurften zu ihrer Ausbreitung grundlegender natürlicher Ressourcen und handwerklicher Fähigkeiten sowie gesellschaftlicher Akzeptanz und Notwendigkeit. Der vorliegende Band untersucht die Anfänge der Eisenverhüttung im polnischen Raum im Bereich der Przeworsk-Kultur, die in der jüngeren vorrömischen Eisenzeit im 2. Jh. v. Chr. liegen sollen. Die Untersuchung bewegt sich dabei in einem Spannungsfeld zwischen vielfältigen Nachweisen von Eisenobjekten aus Gräbern und möglichen Belegen einer Eisenverhüttung im polnischen Raum. Nach aktuellem Forschungsstand ist die Herkunt des Eisens in der vorrömischen Przeworsk-Kultur jedoch nicht mit einer ausgeprägten lokalen oder regionalen Eisenproduktion zu verbinden, sondern basiert vielmehr auf Kommunikations- und Austauschnetzwerken sowohl auf intrakultureller als auch auf interkultureller Ebene vor allem zur Latènekultur. Erst mit dem Übergang zur römischen Kaiserzeit verdichten sich die Nachweise für den Beginn einer weiträumigen Eisenproduktion in Schlesien und Masowien. Dabei ist diese verstärkt einsetzende Eisenverhüttung ab der frühen römischen Kaiserzeit kein isoliertes Phänomen im Bereich der Przeworsk-Kultur, sondern eine Entwicklung, die sich in vielen Regionen des Barbaricums abzeichnet

    Recommendation for a Medical System Concept of Operations for Gateway Missions

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    NASAs exploration missions to cis-lunar space will establish a permanent gateway to future transport missions to Mars. These missions mandate a significant paradigm change for mission planning, spacecraft design, human systems integration, and in-flight medical care due to constraints on mass, volume, power, resupply, and medical evacuation capability. These constraints require medical system development to be tightly integrated with mission and habitat design to provide a sufficient medical infrastructure and enable mission success. This concept of operations provides a vision of medical care needs that will be used to guide the development of a medical system for the cis-lunar Gateway Habitat. This medical system will serve as the precursor to what is implemented in future exploration missions to Mars. This concept of operations documents an overview of the stakeholder needs and system goals of a medical system and provides examples of the types of activities for which the system will be used during the mission. This concept of operations informs the ExMC systems engineering effort to define the Gateway Habitat Medical System by documenting the medical activities and capabilities relevant to Gateway missions, as identified by the ExMC clinician community. In addition, this concept of operations will inform the subsequent systems engineering process of developing technical requirements, system architectures, interfaces, and verification and validation approaches for the medical system. This document supports the closure of ExMC Gap Med01: We do not have a concept of operations for medical care during exploration missions, corresponding to the ExMC-managed human system risk: Risk of Adverse Health Outcomes & Decrements in Performance due to Inflight Medical Conditions

    Medical System Concept of Operations for Mars Exploration Mission-11: Exploration Medical Capability (ExMC) Element - Human Research Program

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    NASAs exploration missions to Mars will have durations of 2-3 years and will take humans farther away from Earth than ever before. This will result in a paradigm shift for mission planning, spacecraft design, human systems integration, and in-flight medical care. Constraints on real-time communication, resupply, and medical evacuation are major architectural drivers. These constraints require medical system development to be tightly integrated with mission and vehicle design to provide crew autonomy and enable mission success. This concept of operations provides a common vision of medical care for developing a medical system for Mars exploration missions. It documents an overview of the stakeholder needs and goals of a medical system and provides examples of the types of activities the system will be used for during the mission. Development of the concept of operations considers mission variables such as distance from Earth, duration of mission, time to definitive medical care, communication protocols between crewmembers and ground support, personnel capabilities and skill sets, medical hardware and software, and medical data management. The information provided in this document informs the ExMC Systems Engineering effort to define the functions to be provided by the medical system. In addition, this concept of operations will inform the subsequent systems engineering process of developing technical requirements, system architectures, interfaces, and verification and validation approaches for the medical system. This document supports the closure of ExMC Gap Med01: We do not have a concept of operations for medical care during exploration missions, corresponding to the ExMC-managed human system risk: Risk of Adverse Health Outcomes & Decrements in Performance due to Inflight Medical Conditions. This document is applicable to the ExMC Element Systems Engineering process and may be used for collaboration within the Human Research Program

    Kein Haushalt ist geschlechtsneutral : Geschlechtergerechte Haushaltsführung als Beitrag zur Demokratisierung der Gesellschaft

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    »We must look for that which we have been trained not to see.« Denkspruch der Weltbank in ihrer Broschüre »Toward Gender Equality« Hartz IV verschärft die Ungleichheit zwischen den Geschlechtern Bundesweit wurden 2003 knapp 184 000 Arbeitslosenhilfeanträge abgelehnt. Zu 75% waren Frauen betroffen. Dieser Trend hielt 2004 an. Durch das Gesamtpaket der Hartz-Gesetze wird sich diese Situation sowohl hinsichtlich von Negativ-Bescheiden für Frauen als auch in bezug auf die generellen Ungleichheiten zwischen Frauen und Männern weiter verschärfen. Damit ist das Hartz IV Gesetz ein anschauliches Beispiel für die Forderung, politische Strategien stets danach zu hinterfragen, welche zu erwartenden direkten und indirekten Wirkungen sie auf Frauen und Männer haben. Bezüglich Hartz IV wurde bereits vor dem In-Kraft-Treten eingeschätzt, dass die Auswirkungen auf die Geschlechter ungleich sein werden. Inhalt Hartz IV verschärft die Ungleichheit zwischen den Geschlechtern Initiative für eine geschlechtergerechte Haushaltsführung in Berlin Zum chronologischen Verlauf Gender Budgeting – was ist das, wie geht es und wem nützt es

    Principles and applications of balanced SSFP techniques

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    During the past 5years balanced steady-state free precession (SSFP) has become increasingly important for diagnostic and functional imaging. Balanced SSFP is characterized by two unique features: it offers a very high signal-to noise ratio and a T2/T1-weighted image contrast. This article focuses on the physical principles, on the signal formation, and on the resulting properties of balanced SSFP. Mechanisms for contrast modification, recent clinical application, and potential extensions of this technique are discusse

    Mechanical fluidity of fully suspended biological cells

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    Mechanical characteristics of single biological cells are used to identify and possibly leverage interesting differences among cells or cell populations. Fluidity---hysteresivity normalized to the extremes of an elastic solid or a viscous liquid---can be extracted from, and compared among, multiple rheological measurements of cells: creep compliance vs. time, complex modulus vs. frequency, and phase lag vs. frequency. With multiple strategies available for acquisition of this nondimensional property, fluidity may serve as a useful and robust parameter for distinguishing cell populations, and for understanding the physical origins of deformability in soft matter. Here, for three disparate eukaryotic cell types deformed in the suspended state via optical stretching, we examine the dependence of fluidity on chemical and environmental influences around a time scale of 1 s. We find that fluidity estimates are consistent in the time and the frequency domains under a structural damping (power-law or fractional derivative)model, but not under an equivalent-complexity lumpedcomponent (spring-dashpot) model; the latter predicts spurious time constants. Although fluidity is suppressed by chemical crosslinking, we find that adenosine triphosphate (ATP) depletion in the cell does not measurably alter the parameter, and thus conclude that active ATP-driven events are not a crucial enabler of fluidity during linear viscoelastic deformation of a suspended cell. Finally, by using the capacity of optical stretching to produce near-instantaneous increases in cell temperature, we establish that fluidity increases with temperature---now measured in a fully suspended, sortable cell without the complicating factor of cell-substratum adhesion

    IMPACT Concept of Operations

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    NASAs future exploration missions mandate a significant paradigm change for mission planning, spacecraft design, human systems integration, and in-flight medical care due to constraints on mass, volume, power, resupply missions, and medical evacuation capabilities. These constraints require further development of the human health and performance system, which includes the medical, task performance, wellness, data, human and other systems necessary to keep the crew healthy and functioning optimally. The human health and performance system will be tightly integrated with mission and habitat design to provide a sufficient human health and performance infrastructure to enable mission success. A suite of systems engineering tools will aid in the decision making process for the development of such a human health and performance system. This Concept of Operations provides a vision for a tool suite to conduct evaluations of human health and performance system options, inform research prioritization, and provide trade study support, based on evidence, risks, and systems engineering principles. The integrated tool suite under development is IMPACT

    The effect of reflux in the continuous separation of hydrocarbon mixtures by rectification

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    Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1924.Includes bibliographical references.by L. P. Elliott and Emil H. M. Lehnhardt.M.S
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