1,648 research outputs found

    Implementing antisemitism studies in German teacher education

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    The integration of antisemitism as a topic for teacher education is urgent, especially in the social sciences Education regarding contemporary antisemitism must be combined with an analysis of racism and historical-political perspectives on the Shoah to succeed in post-migrant society Slight changes of the curricula are a reliable base for further development A nexus between schools, universities and actors of civil society is needed in order to target antisemitism International summer schools, German-Israeli study groups or collaborative workshops are exemplary pilot projects in order to establish competence regarding education critical of antisemitism   Purpose: Following the current rise of antisemitism globally and in Germany, this paper examines the current situation regarding Antisemitism in teacher education. The paper aims to make a contribution for the demand of an implementation of education critical of Antisemitism in teacher education. Approach: Combining experience from university teacher training and the field of extracurricular political education we appoint perspectives for a sustainable implementation of education critical of antisemitism in teacher training via best practice examples. We evaluate the potentials of field trips, international study groups and networks between university and agents located in civil society. Findings: The revised curricula for Social Sciences in the state of North-Rhine-Westphalia (and formerly Berlin) name current antisemitism for the first time, indicating an urgent need for professionalization in Social Science teacher education where the facets of antisemitism only play a minor role. Hence, expertise and existing resource must be stabilized, a structural implementation and funding is needed in order to target the challenging topic of antisemitism. Research limitations/implications: This paper functions as a preliminary research in order to examine the given shape of Social Science teacher education and Antisemitism in Germany. A comprehensive, structured analyses of all teacher training facilities as well as extracurricular agents working in the field of education critical of antisemitism could be useful in order to pool expertise. Nonetheless this paper encourages local collaborations between university and civiliety actors

    Are sketch-and-precondition least squares solvers numerically stable?

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    Sketch-and-precondition techniques are efficient and popular for solving large least squares (LS) problems of the form ⁢= with ∈ℝ× and ≫. This is where is “sketched” to a smaller matrix ⁢ with ∈ℝ⌈⁢⌉× for some constant >1 before an iterative LS solver computes the solution to ⁢= with a right preconditioner , where is constructed from ⁢. Prominent sketch-and-precondition LS solvers are Blendenpik and LSRN. We show that the sketch-and-precondition technique in its most commonly used form is not numerically stable for ill-conditioned LS problems. For provable and practical backward stability and optimal residuals, we suggest using an unpreconditioned iterative LS solver on (⁢)⁢= with =⁢. Provided the condition number of is smaller than the reciprocal of the unit roundoff, we show that this modification ensures that the computed solution has a backward error comparable to the iterative LS solver applied to a well-conditioned matrix. Using smoothed analysis, we model floating-point rounding errors to argue that our modification is expected to compute a backward stable solution even for arbitrarily ill-conditioned LS problems. Additionally, we provide experimental evidence that using the sketch-and-solve solution as a starting vector in sketch-and-precondition algorithms (as suggested by Rokhlin and Tygert in 2008) should be highly preferred over the zero vector. The initialization often results in much more accurate soluti

    Autonomous Quantum Processing Unit: What does it take to construct a self-contained model for quantum computation?

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    Computation is an input-output process, where a program encoding a problem to be solved is inserted into a machine that outputs a solution. Whilst a formalism for quantum Turing machines which lifts this input-output feature into the quantum domain has been developed, this is not how quantum computation is physically conceived. Usually, such a quantum computation is enacted by the manipulation of macroscopic control interactions according to a program executed by a classical system. To understand the fundamental limits of computation, especially in relation to the resources required, it is pivotal to work with a fully self-contained description of a quantum computation where computational and thermodynamic resources are not be obscured by the classical control. To this end, we answer the question; "Can we build a physical model for quantum computation that is fully autonomous?", i.e., where the program to be executed as well as the control are both quantum. We do so by developing a framework that we dub the autonomous Quantum Processing Unit (aQPU). This machine, consisting of a timekeeping mechanism, instruction register and computational system allows an agent to input their problem and receive the solution as an output, autonomously. Using the theory of open quantum systems and results from the field of quantum clocks we are able to use the aQPU as a formalism to investigate relationships between the thermodynamics, complexity, speed and fidelity of a desired quantum computation.Comment: 21 + 18 pages, 1 table, 6 figures. Comments welcom

    Fundamental accuracy-resolution trade-off for timekeeping devices

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    From a thermodynamic point of view, all clocks are driven by irreversible processes. Additionally, one can use oscillatory systems to temporally modulate the thermodynamic flux towards equilibrium. Focusing on the most elementary thermalization events, this modulation can be thought of as a temporal probability concentration for these events. There are two fundamental factors limiting the performance of clocks: On the one level, the inevitable drifts of the oscillatory system, which are addressed by finding stable atomic or nuclear transitions that lead to astounding precision of today's clocks. On the other level, there is the intrinsically stochastic nature of the irreversible events upon which the clock's operation is based. This becomes relevant when seeking to maximize a clock's resolution at high accuracy, which is ultimately limited by the number of such stochastic events per reference time unit. We address this essential trade-off between clock accuracy and resolution, proving a universal bound for all clocks whose elementary thermalization events are memoryless.Comment: 5 + 7 pages, 8 figures, published versio

    Are sketch-and-precondition least squares solvers numerically stable?

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    Sketch-and-precondition techniques are popular for solving large least squares (LS) problems of the form Ax=bAx=b with A∈Rm×nA\in\mathbb{R}^{m\times n} and m≫nm\gg n. This is where AA is ``sketched" to a smaller matrix SASA with S∈R⌈cn⌉×mS\in\mathbb{R}^{\lceil cn\rceil\times m} for some constant c>1c>1 before an iterative LS solver computes the solution to Ax=bAx=b with a right preconditioner PP, where PP is constructed from SASA. Popular sketch-and-precondition LS solvers are Blendenpik and LSRN. We show that the sketch-and-precondition technique is not numerically stable for ill-conditioned LS problems. Instead, we propose using an unpreconditioned iterative LS solver on (AP)y=b(AP)y=b with x=Pyx=Py when accuracy is a concern. Provided the condition number of AA is smaller than the reciprocal of the unit round-off, we show that this modification ensures that the computed solution has a comparable backward error to the iterative LS solver applied to a well-conditioned matrix. Using smoothed analysis, we model floating-point rounding errors to provide a convincing argument that our modification is expected to compute a backward stable solution even for arbitrarily ill-conditioned LS problems.Comment: 22 page

    The Impact of Imperfect Timekeeping on Quantum Control

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    In order to unitarily evolve a quantum system, an agent requires knowledge of time, a parameter which no physical clock can ever perfectly characterise. In this letter, we study how limitations on acquiring knowledge of time impact controlled quantum operations in different paradigms. We show that the quality of timekeeping an agent has access to limits the gate complexity they are able to achieve within circuit-based quantum computation. It also exponentially impacts state preparation for measurement-based quantum computation. Another area where quantum control is relevant is quantum thermodynamics. In that context, we show that cooling a qubit can be achieved using a timer of arbitrary quality for control: timekeeping error only impacts the rate of cooling and not the achievable temperature. Our analysis combines techniques from the study of autonomous quantum clocks and the theory of quantum channels to understand the effect of imperfect timekeeping on controlled quantum dynamics.Comment: 5 + 7 pages, 2 figure

    Simple method for fast deprotection of nucleosides by triethylamine-catalyzed methanolysis of acetates in aqueous medium

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    A straightforward methodology for deacetylation of protected ribonucleosides was developed based on triethylamine-catalyzed solvolysis in aqueous methanol. Reactions are completed in a few minutes under microwave irradiation and the free nucleosides are obtained in high yield after simple evaporation of volatiles. Other important features include the involvement of readily available reagents and the compatibility with diverse functional groups, which make this process very attractive for broad application

    Significance of Coprophagy for the Fatty Acid Profile in Body Tissues of Rabbits Fed Different Diets

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    Four groups of eight New Zealand hybrid rabbits were fattened with ad libitum access to the following pelleted experimental diets: ryegrass meal or alfalfa meal fed either alone or with oats meal in a ratio of 1:1. After 25weeks they were slaughtered and dissected. Fatty acid (FA) profiles of caecotrophs (re-ingested fermentation products of the caecum), perirenal adipose tissue and intramuscular fat in the Musculus quadriceps were determined. With high proportions of branched-chain FA (BFA) and trans FA, and increased proportions of saturated FA relative to the diets, the caecotroph FA profile showed a clear fingerprint of anaerobe microbial lipid metabolism including biohydrogenation. By contrast, the FA profiles of adipose and lean tissue comprised high proportions of polyunsaturated FA (PUFA), whilst BFA and trans FA occurred in much lower proportions compared to the caecotrophs. Thus, coprophagy did not substantially modify the FA composition of the tissues investigated. Use of forage-only diets, compared to the oats supplemented diets, led to extraordinary high proportions of n-3 PUFA (including 18:3 and long-chain n-3) in the fat of adipose (21.3 vs. 6.7%) and lean tissue (15.4 vs. 5.7%). The forage type diet (grass vs. alfalfa) had smaller effects on the FA profiles. Indications of diet effects on endogenous desaturation, chain elongation and differential distribution of functional FA between the two tissues investigated were foun

    Raufutter als Alleinfutter für Kaninchen – Auswirkungen auf das Fettsäurenmuster des Fleisches

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    Four groups of eight New Zealand hybrid rabbits were fed ryegrass meal only, alfalfa meal only, ryegrass and oats 1:1, or alfalfa and oats 1:1. Diets were offered ad libitum in pelleted form from 5-30 weeks of age, when they were slaughtered. Intramuscular fatty acid profiles were determined in the Musculus quadriceps of the left hindleg. Feed intake was not statistically different between the four groups, nor was carcass weight. The main effect of the forage-only diets on the fatty acid profiles was a decrease of monounsaturated and an increase of polyunsaturated fatty acid (PUFA) proportions. Within PUFA, the n-3 fatty acids more than doubled with forage-only compared to forage-oats diets, while the n-6 fatty acids slightly decreased. In general, the proportion of n-3 fatty acids in intramuscular fat of forage-only fed rabbits was extraordinarily high compared to any other meat of agricultural origin. The results demonstrate a specific advantage of roughage-based diets in the nutrition of productive herbivores, which is also known for ruminants
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