A note on chances and limitations of psychometric AI

Human-level artificial intelligence (HAI) surely is a special research endeavor in more than one way: In the first place, the very nature of intelligence is not entirely clear; there are no criteria commonly agreed upon necessary or sufficient for the ascription of intelligence other than similarity to human performance (and even this criterion is open for a plethora of possible interpretations); there is a lack of clarity concerning how to properly investigate HAI and how to proceed after the very first steps of implementing an HAI system; etc. In this note I assess the ways in which the approach of Psychometric Artificial Intelligence [1] can (and cannot) be taken as a foundation for a scientific approach to HAI

Irradiation of Materials with Short, Intense Ion pulses at NDCX-II

We present an overview of the performance of the Neutralized Drift Compression Experiment-II (NDCX-II) accelerator at Berkeley Lab, and report on recent target experiments on beam driven melting and transmission ion energy loss measurements with nanosecond and millimeter-scale ion beam pulses and thin tin foils. Bunches with around 10^11 ions, 1-mm radius, and 2-30 ns FWHM duration have been created with corresponding fluences in the range of 0.1 to 0.7 J/cm^2. To achieve these short pulse durations and mm-scale focal spot radii, the 1.1 MeV He+ ion beam is neutralized in a drift compression section, which removes the space charge defocusing effect during final compression and focusing. The beam space charge and drift compression techniques resemble necessary beam conditions and manipulations in heavy ion inertial fusion accelerators. Quantitative comparison of detailed particle-in-cell simulations with the experiment play an important role in optimizing accelerator performance.Comment: 15 pages, 7 figures. revised manuscript submitted to Laser and Particle Beam

Effects of memory training or task design? A commentary on 'neural evidence for the use of digit-image mnemonic in a superior memorist: an fMRI study'

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Conceptualising a university teaching practice in an activity theory perspective

In this article I present a theorisation of a university mathematics teaching practice, based on a research study into the teaching of linear algebra in a first year mathematics undergraduate course. The research was largely qualitative and consisted of data collected in interviews with the lecturer and in observations of his lectures. Using Leontiev’s (1981) activity theory framework I categorised the teaching of linear algebra on three levels: activity-motive, actions-goals and operations-conditions. Each level of analysis provided insights into the lecturer’s teaching approach, his motivation, his intentions and his strategies in relation to his teaching. I developed a model of the teaching process that relates goals as expressed by the lecturer in interviews to the strategies that he designed for his teaching

Effective connectivity reveals strategy differences in an expert calculator

Mathematical reasoning is a core component of cognition and the study of experts defines the upper limits of human cognitive abilities, which is why we are fascinated by peak performers, such as chess masters and mental calculators. Here, we investigated the neural bases of calendrical skills, i.e. the ability to rapidly identify the weekday of a particular date, in a gifted mental calculator who does not fall in the autistic spectrum, using functional MRI. Graph-based mapping of effective connectivity, but not univariate analysis, revealed distinct anatomical location of “cortical hubs” supporting the processing of well-practiced close dates and less-practiced remote dates: the former engaged predominantly occipital and medial temporal areas, whereas the latter were associated mainly with prefrontal, orbitofrontal and anterior cingulate connectivity. These results point to the effect of extensive practice on the development of expertise and long term working memory, and demonstrate the role of frontal networks in supporting performance on less practiced calculations, which incur additional processing demands. Through the example of calendrical skills, our results demonstrate that the ability to perform complex calculations is initially supported by extensive attentional and strategic resources, which, as expertise develops, are gradually replaced by access to long term working memory for familiar material

N,O- und N,C,N-koordinierte Platinmetallkomplexe: Synthesen, Strukturen und katalytische Anwendungen

The selected β-amino alcohols acted as N-monodentate ligands towards the dirhodium complex [(C8H12)2Rh2(Cl)2] to form [(C8H12)RhCl{HN(R)_OH}] by nucleophilic cleavage of the chlorido bridges. Many of such complexes have been characterized by X-ray diffractometry. Coordination of the free hydroxy function of the N,O-ligands was brought about either by dehydrochlorination to furnish the alcoholato chelates [(C8H12)Rh(H2NCMe2CH2O)] and [(C8H12)Rh{(S)-H2NCH(CHMe2)CH2O}] or by precipitation of the metal-bound chloride as TlCl, which converted the neutral [(C8H12)RhCl{HN(R)_OH}] compounds into cationic [(C8H12)Rh{HN(R)_OH}]+ amino alcohol chelate complexes.Such complexes were examined for their activity in asymmetric catalysis. Though being able to hydrogenate C=C- and C=O-double bonds the catalysts displayed only a limited tendency toward enantioselectivity due to facile loss of their N,O-ligands in the course of the reaction and subsequent decomposition. The heterolytic cleavage of the hydrogen bond in coordinatively unsaturated amido derivatives of platinum metals is a key step in ruthenium-catalyzed C=O-hydrogenation reactions. In order to evaluate such amido intermediates and their role in asymmetric catalysis transition metal complexes were synthesized which contained the novel bidentate N,C,N-pincerligand: 1,3-Bis(aminoisopropyl)benzene.The ditertiary carbinamine 1,3-C6H4(CMe2NH2)2 was prepared by a simple two-step synthesis starting from 1,3-C6H4(CMe2NCO)2. Studies of its coordination behavior towards platinum metal ions showed that the diamine can form bimetallic complexes such as [{(C8H12)2RhCl}2{1,3-C6H4(CMe2NH2)2} and trans,trans-[{1,3-C6H4(CMe2NH2)2}2(PdCl2)]2 with one or two N,N-bridges, and can also produce N,C,N-chelated metalaheterocycles as examplified by [{2,6-C6H3(CMe2NH2)2}PdCl]. Replacement of the substitutionally labile chlorido ligand by PEt3 afforded the phosphine-containing complex [{2,6-C6H3(CMe2NH2)2}Pd(PEt3)]Cl.Durch Reaktion von achiralen wie auch optisch aktiven ß-Aminoalkoholen mit geeigneten Precursoren wie z.B. [(C8H12)2Rh2(Cl)2] gelang so die Darstellung von Verbindungen, in welchen der Ligand einzähnig über das Stickstoffatom gebunden ist. Die Koordination der freien OH-Gruppe des N,O-Liganden erfolgte entweder durch Dehydrochlorierung unter Bildung der neutralen Alkoholato-Komplexe [(C8H12)Rh(H2NCMe2CH2O)] und [(C8H12)Rh{(S)-H2NCH(CHMe2)-CH2O}] oder durch Fällung des metallgebundenen Chlorids als schwerlösliches Thalliumchlorid. Die anschließende Substitution der Dien-Liganden mit (R)-BINAP lieferte kationische Verbindungen des Typs [(R2P_PR2)Rh(H2N_OH)]+.Derartige Komplexe wurden auf ihr Potential in der asymmetrischen Katalyse untersucht, zwar erwiesen sie sich als fähig C=C- sowie C=O-Doppelbindungen zu hydrieren, jedoch verliefen diese Katalysen nur bedingt enantioselektiv, da die Katalysatoren unter Verlust ihrer N,O-Liganden im Verlauf der Reaktionen abgebaut wurden. Die heterolytische Spaltung der Bindung des Diwasserstoff-Moleküls an der Metall-Amid-Funktion unterkoordinierter Amidokomplexe ist ein entscheidender Zwischenschritt der Ruthenium-katalysierten C=O-Hydrierung. Mit dem Ziel solche koordinativ ungesättigten Amidointermediate der enantioselektiven Hydrierung besser untersuchen zu können wurden Übergangsmetallkomplexe synthetisiert, die einen neuartigen N,C,N-Pinzettenliganden enthielten: 1,3-Bis(aminoisopropyl)benzol. Das Diamin ist in der Lage zweikernige Metallkomplexe zu bilden, wie z.B. [{(C8H12)2RhCl}2{1,3-C6H4(CMe2NH2)2} und trans,trans-[{μ-1,3-C6H4(CMe2NH2)2}2-(PdCl2)]2 und dabei als N,N-verbrückener Ligand zu fungieren. Der Pinzettenligand reagierte außerdem mit PdCl2 oder K2[PdCl4] unter Cyclometallierung zum N,C,N-chelatisierten Metallaheterocyclus [{2,6-C6H3(CMe2NH2)2-PdCl] der sich wiederum als substitutionslabil gegenüber einfachen Phosphinen erwies und mit PEt3 den strukturanalytisch eindeutig charakterisierten Komplex [{2,6-C6H3(CMe2NH2)2}Pd(PEt3)]Cl lieferte

High Repetition-Rate Laser-Driven Particle Generation – Towards High Flux Fast Neutron Sources

High-flux, high repetition-rate pulsed neutron sources are of interest for probing studies such as neutron-induced damage processes in materials employed and considered for shielding purposes in fusion reactors. Simulating the effect an intense neutron flux has on such materials will ultimately guide designs for future fusion reactors. Laser-driven neutron sources employing petawatt laser systems show great potential to fulfill the need for such a neutron source. One of the most common approaches for neutron generation utilizing lasers as drivers is the pitcher–catcher geometry in which a directional ion beam is generated from a pitcher target and impinges on a catcher target producing neutrons through nuclear reactions within the catcher material. Despite the fact that neutron generation using such setups have only recently gained attention, it has so far shown the highest neutron yields using short-pulse lasers. To date, experiments predominantly studied neutron generation on a single shot basis, especially since the development of a high repetition-rate laser-driven neutron source faces a variety of challenges. In this thesis, the individual components of a successful high repetition-rate laser-driven neutron source were investigated and developed. The focus of this work was especially the development of a stable target system compatible with high repetition-rate laser operations, the development of a design for the catcher target, allowing for optimization of ion beam-catcher overlap, and an efficient ion and neutron beam detection platform. For this work, a robust version of the SLAC-developed converging liquid microjet target delivery systems was designed and fielded. This system was successfully implemented at two different laser facilities, surviving more than 1000 shots on target with no apparent damage to the nozzle or degradation of the liquid target. The liquid microjet system was implemented to study high repetition-rate deuteron acceleration from heavy water microjet targets at the ALEPH laser facility reaching average fluxes of 1×10^12 deuterons/sr/min at a repetition rate of 0.5 Hz. Stable deuteron acceleration over 60 shots was observed at varying laser energies on target, suggesting a more favorable scaling of the ion beam cut-off energy than currently established in the literature. A flexible, repetition-rate compatible neutron generation platform was designed around a stackable catcher target, which can be adjusted based on laser parameters and experimental conditions. This specific design aims at enhancing the generation of high-flux, directional neutron beams. A flexible detector setup simultaneously monitors the ion and neutron beam emission characteristics to study their individual shot-to-shot parameter changes and the correlations between them. Employing cryogenic or ambient-temperature liquid jet targets as a pitcher enables high-repetition-rate operation. This novel platform was successfully tested using cryogenic liquid deuterium jet targets at the Texas Petawatt laser facility demonstrating efficient generation of forward directed neutron beams with fluxes reaching 7.2×10^9 neutrons/sr within a narrow divergence angle of ±20◦. As such, this work lays the foundation for future high-repetition-rate experiments towards pulsed, high-flux, fast neutron sources for radiation-induced effect studies relevant for fusion science and applications that require neutron beams with short pulse duration for the probing of fast evolving processes complementary to X-rays

Linear algebra with a didactical focus

How might you construct an introductory linear algebra course for first year mathematics students? What decisions would you have to make and what issues would you have to address? Barbara Jaworski, Stephanie Treffert-Thomas and Thomas Bartsch, as a small research team, set out to address these questions and others relating to a first year, first semester module in linear algebra. The authors are all members of the School of Science at Loughborough University, they all teach mathematics and do research into mathematics or mathematics education. Thomas Bartsch is a mathematician working in the Department of Mathematical Sciences; Barbara Jaworski and Stephanie Treffert-Thomas are mathematics educators working in the Mathematics Education Centre