cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
title: Phytochemical, Chemopreventive and Antimalarial Activity Evaluation of Five Selected Medicinal Plants from the Cameroonian Flora
Creators: name: Guetchueng Tamdem, S
Publisher: name: Liverpool John Moores University
Year: 2019

description: Screening of ethnomedicinal plants for antimalarial and chemopreventive activities among plants used in Cameroonian folklore medicine to treat fevers, malaria and tumour was conducted on Croton oligandrus (Euphorbiaceae), Justicia hypocrateriformis (Acanthanceae), Pseudospondias microcarpa (Anacardiaceae), Zanthoxylum lepreurii and Zanthoxylum zanthoxyloides (Rutaceae). The selection of plants was based on ethnomedicinal use and literature review. Bioassay-guided isolation of active components from the active plants was performed with the aim to scientifically validate their folklore usage. The plant materials were dried, ground, and Soxhlet-extracted, successively, with n-hexane, dichloromethane (DCM) and methanol (MeOH). The antimalarial and chemopreventive potential of the plants were evaluated using haem polymerisation and the luciferase assays, respectively. The n-hexane and the DCM extracts of C. oligandrus, and the DCM and MeOH extracts of Z. zanthoxyloides were the most active in the luciferase assay causing 18, 21, 34 and 36-fold induction of the level of luciferase in AREc32 cells, respectively. Pseudospondias microcarpa was the most active antimalarial plant with IC50 values of 73.9 ± 25.8, 2.5 ± 1.5 and 4.0 ± 1.7 µM for the stem bark n-hexane, DCM and MeOH extracts, respectively, and 13.0 ± 9.0 µM for the leaves MeOH extract. Fifty-one compounds including eleven novel ones were isolated from active fractions using column chromatography, thin layer chromatography and reversed-phase high-pressure liquid chromatography. Structural elucidation was carried out by spectroscopic means including 1D and 2D NMR and mass spectrometry. Crotonolins A-D, skimmianine, hesperidin and myrtopsine were identified as potent chemopreventive compounds with fold induction greater than 2. None of the isolated compounds demonstrated any inhibition of haem polymerisation. This study generated the first phytochemical report on P. microcarpa, the second of C. oligandrus and the third of J. hypocrateriformis. The biogenesis and chemotaxonomy of isolated compounds have also been discussed.
[2.2](4,7)Isobenzofuranophanes - Synthesis, Characterisation and Reactivity
Creators: name: König, Burkhard
name: Ramm, Sonja
name: Bubenitschek, Peter
name: Jones, Peter G.
name: Hopf, Henning
name: Knieriem, Burkhard
name: Meijere, Armin de
Publisher: name: Universität Regensburg
Year: 1994
Subjects: subject: [2.2]Paracyclophanes, new derivatives of; Isobenzofuranophanes, preparation and cycloadditions
subject: 540 Chemie

description: The isomeric Diels-Alder adducts 3, obtained by cycloaddition of tetraphenylcyclopentadienone to the 4,5:12,13-bis-(oxanorbornadieno)[2.2]paracyclophanes syn,syn- and anti,-syn-2[Note ][The stereochemical descriptors syn and anti refer to the orientation of the oxygen bridge in the oxabicyclo[2.2.1]heptadiene subunits with respect to the [2.2]paracyclophaneskeleton.], yield the unstable isobenzofuranophane 4 by consecutive extrusion of carbon monoxide and tetraphenylbenzene when heated to 180°C. The molecular ion of 4 was observed in the EI mass spectrum. The stable tetraphenyl-substituted analogue 10 was synthesized independently from the previously unknown 4,5,12,13-tetrabenzoyl[2.2]paracyclophane (9). UV/Vis as well as fluorescence spectra and an X-ray crystal structure analysis of 9 are reported.
Diels-Alder Reactions of [2.2]Paracyclophane-1-ene and [2.2]Paracyclophane-1,9-diene with 3,6-Disubstituted 1,2,4,5-Tetrazines
Creators: name: Meijere, Armin de
name: König, Burkhard
Publisher: name: Universität Regensburg
Year: 1992
Subjects: subject: 540 Chemie

description: [2.2] Paracyclophan-1-ene (1) and [2.2] paracyclophane-1,9-diene (6) apparently act as dienophiles with inverse electron demand and smoothly react with dimethyl 1,2,4,5-tetrazine-3,6-dicarboxylate (2a) at room temperature forming dihydropyridazine adducts, which are dehydrogenated to the pyridazino-anellated [2.2] paracyclophanes 5a and 8a, respectively. The molecular structure of 5a is determined by X-ray crystal-structure analysis. Under more rigorous conditions, phenyl-substituted derivatives 5b and 8b are obtained from 1 and 6, respectively, with 3,6-diphenyl-1,2,4,5-tetrazine. Compounds 1 and 6 are less reactive dienophiles than other strained cyclic olefins as shown by kinetic measurements.
Hilbert basis of the Lipman semigroup
Creators: name: Sahin, Mesut
Publisher: name: arXiv
Year: 2010
Subjects: subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics
subject: 14E15, 14M25, 13A50, 05E40

description: In this work, we give a new method to compute the Hilbert basis of the semigroup of certain positive divisors supported on the exceptional divisor of a normal surface singularity. Our approach is purely combinatorial which permits to avoid the long calculation of the invariants of the ring as it is presented in the work of Altinok and Tosun.
description: In Theorem~4, the Cartesian product $S = S_1 \times S_2$ is replaced with a fiber product $S = S_1 \times_{\mathcal{E}} S_2$, thanks are due to Zach Teitler for his careful reading
Synthesis and Diels-Alder Reactions of 1,2-Dimethylene- and 1,2,9,10-Tetramethylene-[2.2]paracyclophane: New Routes to Bridge-Anellated[2.2]Paracyclophanedienes
Creators: name: König, Burkhard
name: Meijere, Armin de
Publisher: name: Universität Regensburg
Year: 1992
Subjects: subject: Bisdienes; Diels-Alder reaction with p-benzoquinone; p-Cyclophanes, bridge-anellated
subject: 540 Chemie

description: The title compounds 8 and 1 have been synthesized in three steps each from 1,2-dibromo[2.2]paracyclophan-1-ene (2) and 1,2,9,10-tetrabromo[2.2]paracyclophane-1,9-diene (4), respectively. Copper-mediated coupling of vinyl bromides 2 and 4 with methyl- and phenylmagnesium bromide gives substituted [2.2]paracyclophanes 3-CH3, 3-Ph, 5-CH3, and 5-Ph in good yields. The high reactivity of the [2.2]paracyclophane-1,2-dimethylene moieties in 8 and 1 in Diels-Alder reactions has been verified in cycloadditions with p-benzoquinone to give 10 and 13 and with naphthalene 1,4-endoxide to yield 12.
Residual Minimizing Model Interpolation for Parameterized Nonlinear Dynamical Systems
Creators: name: Constantine, Paul G.
name: Wang, Qiqi
Publisher: name: arXiv
Year: 2010
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics

description: We present a method for approximating the solution of a parameterized, nonlinear dynamical system using an affine combination of solutions computed at other points in the input parameter space. The coefficients of the affine combination are computed with a nonlinear least squares procedure that minimizes the residual of the governing equations. The approximation properties of this residual minimizing scheme are comparable to existing reduced basis and POD-Galerkin model reduction methods, but its implementation requires only independent evaluations of the nonlinear forcing function. It is particularly appropriate when one wishes to approximate the states at a few points in time without time marching from the initial conditions. We prove some interesting characteristics of the scheme including an interpolatory property, and we present heuristics for mitigating the effects of the ill-conditioning and reducing the overall cost of the method. We apply the method to representative numerical examples from kinetics - a three state system with one parameter controlling the stiffness - and conductive heat transfer - a nonlinear parabolic PDE with a random field model for the thermal conductivity.
description: 28 pages, 8 figures, 2 tables
Palladium-Catalyzed Coupling of Vinylferrocene with Aromatic Halides - A Highly Efficient Route to (Ferrocenylvinyl)arenes
Creators: name: König, Burkhard
name: Zieg, H.
name: Bubenitschek, P.
name: Jones, P. G.
Publisher: name: Universität Regensburg
Year: 1994
Subjects: subject: Vinylferrocene , Palladium-catalyzed couplin , (Ferrocenylvinyl)arenes
subject: 540 Chemie

description: (Ferrocenylvinyl)arenes 3, 5, and 7 are obtained from vinylferrocene (1) and substituted aromatic and heteroaromatic halides by palladium-catalyzed Heck-type reactions. Up to three ferrocene units are introduced in one step by the multi-fold reaction of 1,2-dibromo- (4) or 1,3,5-tribromobenzene (6) with 1. The first crystal structure of a bis(ferrocenylvinyl)benzene chromophore (5) is reported.
Practical and accurate calculations of Askaryan radiation
Creators: name: Alvarez-Muñiz, Jaime
name: Romero-Wolf, Andrés
name: Zas, Enrique
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: An in-depth characterization of coherent radio Cherenkov pulses from particle showers in dense dielectric media, referred to as the Askaryan effect, is presented. The time-domain calculation developed in this article is based on a form factor to account for the lateral dimensions of the shower. It is computationally efficient and able to reproduce the results of detailed particle shower simulations with high fidelity in most regions of practical interest including Fresnel effects due to the longitudinal development of the shower. In addition, an intuitive interpretation of the characteristics of the Askaryan pulse is provided. We expect our approach to benefit the analysis of radio pulses in experiments exploiting the radio technique.
description: Replaced with version published Phys. Rev. D
Essays in behavioral economics
Creators: name: Chakraborty, Anujit
Publisher: name: University of British Columbia
Year: 2017

description: This thesis studies individual choice in both individualistic and interactive decisions, under different situations of risk, uncertainty and time delay. The first chapter of my dissertation investigates the tendency of human beings to make choices that are biased towards alternatives in the present. I characterize the general class of utilities which are consistent with present-biased behavior. I show that any present-biased preference has a subjective max-min representation, which can be cognitively interpreted as the decision maker considering the most conservative “present equivalents” in the face of subjective uncertainty about future tastes. The second chapter of my thesis provides desiderata of choice consistency that experimenters should employ while estimating time preferences from choice data. We also show how application of this desiderata can help us learn new insights from previous experimental studies. The third chapter of my thesis establishes a tight relation between non-standard behaviors in the domains of risk and time by considering a decision maker with non-expected utility preferences who believes that only present consumption is certain while any future consumption is uncertain. We provide the first complete characterization of the two-way relations between i) certainty effect and present bias, and, ii) common ratio effect and the common difference effect. A corollary to our results is that hyperbolic discounting implies the Common Ratio Effect and that quasi-hyperbolic discounting implies the Certainty Effect. In the fourth chapter of my thesis, I use variation in experimental design (time-discounting) and belief data from subjects to investigate the determinants of behavior in Finitely Repeated Prisoner's Dilemma games.
Перспективы применения турбогенераторных установок малой мощности для предприятий горно-металлургической отрасли
Creators: name: Николаевич, Минко Александр
name: Владимировна, Шевченко Валентина
Publisher: name: Zenodo
Year: 2016
Subjects: электрические машины
турбогенераторы
ТГ
энергоресурсы
энергосбережение
ТГ малой мощности
ТГ в горно-металлургической отрасли

description: На русском: [Минко А.Н., Шевченко В.В. Перспективы применения турбогенераторных установок малой мощности для предприятий горно-металлургической отрасли // Тезисы докладов 24-й международной научно-практической конференции "Информационные технологии: наука, техника, технология, образование, здоровье" (MicroCAD-2016), 18-20 мая 2016 года, Харьков (ISSN 2222-2944), часть 2, cекция 9 "Электромеханическое и электрическое преобразование энергии". - Украина, Харьков: НТУ "ХПИ", 2016. - С. 112. https://doi.org/10.5281/zenodo.2595602]

Ключевые слова: электрические машины, турбогенераторы (ТГ), энергоресурсы, энергосбережение, ТГ малой мощности, ТГ в горно-металлургической отрасли.

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Extensions of Toric Varieties
Creators: name: Sahin, Mesut
Publisher: name: arXiv
Year: 2010
Subjects: subject: Commutative Algebra (math.AC)
subject: Algebraic Geometry (math.AG)
subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 14M25, 13D40, 14M10, 13D02

description: In this paper, we introduce the notion of "extension" of a toric variety and study its fundamental properties. This gives rise to infinitely many toric varieties with a special property, such as being set theoretic complete intersection or arithmetically Cohen-Macaulay (Gorenstein) and having a Cohen-Macaulay tangent cone or a local ring with non-decreasing Hilbert function, from just one single example with the same property, verifying Rossi's conjecture for larger classes and extending some results appeared in literature.
description: 8 pages
Components in time-varying graphs
Creators: name: Nicosia, V.
name: Tang, J.
name: Musolesi, M.
name: Russo, G.
name: Mascolo, C.
name: Latora, V.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Physics and Society (physics.soc-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Social and Information Networks (cs.SI)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: Real complex systems are inherently time-varying. Thanks to new communication systems and novel technologies, it is today possible to produce and analyze social and biological networks with detailed information on the time of occurrence and duration of each link. However, standard graph metrics introduced so far in complex network theory are mainly suited for static graphs, i.e., graphs in which the links do not change over time, or graphs built from time-varying systems by aggregating all the links as if they were concurrent in time. In this paper, we extend the notion of connectedness, and the definitions of node and graph components, to the case of time-varying graphs, which are represented as time-ordered sequences of graphs defined over a fixed set of nodes. We show that the problem of finding strongly connected components in a time-varying graph can be mapped into the problem of discovering the maximal-cliques in an opportunely constructed static graph, which we name the affine graph. It is therefore an NP-complete problem. As a practical example, we have performed a temporal component analysis of time-varying graphs constructed from three data sets of human interactions. The results show that taking time into account in the definition of graph components allows to capture important features of real systems. In particular, we observe a large variability in the size of node temporal in- and out-components. This is due to intrinsic fluctuations in the activity patterns of individuals, which cannot be detected by static graph analysis.
description: 12 pages, 4 figures, 3 tables
Zirconocene Complexes of [2.2]Paracyclophane with Formal Triple Bonds in the Bridges
Creators: name: König, Burkhard
name: Bennett, Martin A.
name: Meijere, Armin de
Publisher: name: Universität Regensburg
Year: 1994
Subjects: subject: 540 Chemie

description: Zirconocene complexes of [2.2]paracylophanes with formal triple bonds in the bridges, corresponding to zirconacyclo-propenes, were synthesized from [2.2]paracylophan-1-ene (1) and 1,9(10)-dibromo[2.2]paracyclophan-1,9-diene (5) via their vinyl lithium derivatives and characterized by spectroscopic methods. The zirconocene-alkyne complexes 7, 9 react with bromine or iodine with loss of the bis(cyclopentadienyl)zirconium moiety to yield the expected stable halogenated products 8 and 10, respectively. Insertion of 2-butyne into the initially formed 16e complexes gave zirconacyclopentadiene complexes 3, 9.
Embodied perception during walking using Deep Recurrent Neural Networks
Creators: name: Chen, Jacob
Publisher: name: University of British Columbia
Year: 2017

description: Movements such as walking require knowledge of the environment in order to be robust. This knowledge can be gleaned via embodied perception. While information about the upcoming terrain such as compliance, friction, or slope may be difficult to directly estimate, using the walking motion itself allows for these properties to be implicitly observed over time from the stream of movement data. However, the relationship between a parameter such as ground compliance and the movement data may be complex and difficult to discover. In this thesis, we demonstrate the use of a Deep LSTM Network to estimate slope and ground compliance of terrain by observing a stream of sensory information that includes the character state and foot pressure information.
Ein allgemeiner Zugang zu starren Systemen mit alternierenden orthogonalen Arene-Einheiten über Diels-Alder Reaktionen
Creators: name: König, Burkhard
name: Heinze, Jürgen
name: Meerholz, Klaus
name: Meijere, Armin de
Publisher: name: Universität Regensburg
Year: 1991
Subjects: subject: 540 Chemie

description: auch erschienen in: Angew. Chem. Int. Ed. Engl 30, 1361 - 1362 (1991)
Observation of the Far-ultraviolet Continuum Background with SPEAR/FIMS
Creators: name: Seon, K. -I.
name: Edelstein, J.
name: Korpela, E.
name: Witt, A.
name: Min, K. -W.
name: Han, W.
name: Shinn, J.
name: Kim, I. -J.
name: Park, J. -W.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present the general properties of the far-ultraviolet (FUV; 1370-1720A) continuum background over most of the sky, obtained with the Spectroscopy of Plasma Evolution from Astrophysical Radiation instrument (SPEAR, also known as FIMS), flown aboard the STSAT-1 satellite mission. We find that the diffuse FUV continuum intensity is well correlated with N_{HI}, 100 $μ$m, and H-alpha intensities but anti-correlated with soft X-ray. The correlation of the diffuse background with the direct stellar flux is weaker than the correlation with other parameters. The continuum spectra are relatively flat. However, a weak softening of the FUV spectra toward some sight lines, mostly at high Galactic latitudes, is found not only in direct-stellar but also in diffuse background spectra. The diffuse background is relatively softer that the direct stellar spectrum. We also find that the diffuse FUV background averaged over the sky has about the same level as the direct-stellar radiation field in the statistical sense and a bit softer spectrum compared to direct stellar radiation. A map of the ratio of 1400-1510A to 1560-1660A shows that the sky is divided into roughly two parts. However, this map shows a lot of patchy structures on small scales. The spatial variation of the hardness ratio seems to be largely determined by the longitudinal distribution of spectral types of stars in the Galactic plane. A correlation of the hardness ratio with the FUV intensity at high intensities is found but an anti-correlation at low intensities. We also find evidence that the FUV intensity distribution is log-normal in nature.
description: 39 pages, 26 figures, accepted for publication in ApJS
Time Varying Uncertainty and the Credit Channel
Creators: name: Dorofeenko, Victor
name: Lee, Gabriel
name: Salyer, Kevin
Publisher: name: Universität Regensburg
Year: 2008
Subjects: subject: agency costs; credit channel; time-varying uncertainty
subject: 330 Wirtschaft

description: We extend the Carlstrom and Fuerst (American Economic Review, 1997, 87, pp. 893–910) agency cost model of business cycles by including time-varying uncertainty in the technology shocks that affect capital production. We first demonstrate that standard linearization methods can be used to solve the model yet second moments enter the economy’s equilibrium policy functions.We then demonstrate that an increase in uncertainty causes, ceteris paribus, a fall in investment supply. We also show that persistence of uncertainty affects both quantitatively and qualitatively the behaviour of the economy.
Queen-queen competition and reproductive skew in a Cardiocondyla ant
Creators: name: yamauchi, K.
name: Ishida, Y.
name: Hashim, R.
name: Heinze, J.
Publisher: name: Universität Regensburg
Year: 2007
Subjects: subject: Reproductive skew; queen fighting; dominance; color polymorphism
subject: 570 Biowissenschaften, Biologie
subject: 590 Tiere (Zoologie)

description: Queens and female sexuals of the Southeast Asian ant Cardiocondyla sp. engage in aggressive interactions. By biting and violently antennating female sexuals, queens appear to prevent them from shedding their wings and presumably also from starting to lay haploid eggs. Aggression among dealate queens apparently results in the establishment of reproductive rank orders with considerable differences in offspring production among individual nestmate queens, as visualized by the pronounced color polymorphism of this taxon. Reproductive skew ranged from complete monopolization of both worker and female sexual production to more or less equal partitioning of reproduction. Division of reproduction was associated with variation in the location of queens close to or away from the center of the brood pile, which again appeared to be caused by queen-queen antagonism.
Back to one: consequences of derived monogyny in an ant with polygynous ancestors
Creators: name: Schrempf, Alexandra
name: Heinze, Jürgen
Publisher: name: Universität Regensburg
Year: 2007
Subjects: subject: Cardiocondyla; colony founding; longevity; queen number; queen polymorphism; trade-off reproduction–dispersal; wing muscle polymorphism
subject: 570 Biowissenschaften, Biologie
subject: 590 Tiere (Zoologie)
subject: Animals
subject: Ants/anatomy & histology
subject: Body Fat Distribution
subject: Feeding Behavior
subject: Female
subject: Flight, Animal
subject: Longevity
subject: Male
subject: Reproduction/physiology
subject: Sexual Behavior, Animal
subject: Wing/physiology

description: The number of queens per colony is of fundamental importance in the life history of social insects. Multiple queening (polygyny), with dependent colony founding by budding, has repeatedly evolved from ancestral single queening (monogyny) and independent founding by solitary queens in waSPS, bees and ants. By contrast, the reversal to monogyny appears to be rare, as polygynous queens often lack morphological adaptations necessary for dispersal and independent colony founding. In the ant genus Cardiocondyla, monogynous species evolved from polygynous ancestors. Here, we show that queens of monogynous species found their colonies independently, albeit in an unusual way: they mate in the maternal nest, disperse on foot and forage during the founding phase. This reversal appears to be associated with the occurrence of a wing polymorphism, which reflects a trade-off between reproduction and dispersal. Moreover, queens of monogynous species live considerably longer than queens in related polygynous taxa, suggesting that queen life span is a plastic trait.
Linking smallholders to livestock markets in Tanzania: combing market and household survey data
Creators: name: Pica-Ciamarra, Ugo
name: Baker, Derek
name: Chassama, John
name: Fadiga, Mohamadou
name: Nsiima, Longin
Publisher: name: Gates Open Research
Year: 2019

description: Linking smallholders to livestock markets in Tanzania: combing market and household survey data
The effect of self-correction on implicit and explicit representational change in children’s problem-solving
Creators: name: Yuniarto, Laras Sekarrini
Publisher: name: The University of St Andrews
Year: 2022
Subjects: Problem-solving
Mental representation
Implicit and explicit representation
Cognitive development
Preschool children
Representational Redescription Model

description: Children’s understanding of problems becomes more abstract and sophisticated as they gain experience with solving them. This thesis uses the framework of the Representational Redescription Model (RRM; Karmiloff-Smith, 1992) to capture how children’s representations progress from implicit to explicit through a process of representational redescription, which progressively re-represents information in the mind to make it more conscious, manipulable, and accessible to verbal and gestural report. In particular, I focus on the RRM’s claim that redescription is triggered through a period of behavioural success without explicit understanding. The lack of opportunities to achieve such implicit, procedural success may explain why young children fail to solve causal problems that they might otherwise understand (e.g., trap-tasks). The RRM suggests that modifying such tasks to facilitate behavioural mastery, such as by incorporating correction of one’s mistakes, might improve performance and understanding amongst young children. The empirical studies of this thesis investigated the role of self-correction on problem-solving in 2.5- and 3-year-old children. Using a physical trap-task, Study 1 showed that self-corrective practice (compared to non-corrective practice) led to significant improvements in performance when the role of the trap was reversed. Study 2 extended these findings to a digital trap-task, finding that such improvement was not unique to self-correction but could be elicited through extra remedial trials as well. In Study 1, self-correction benefited all ages, while in Study 2, only older children benefited. However, in both studies, children could explain the task appropriately for their age regardless of their performance or their practice condition. I discuss my interpretation of these findings as possible evidence of partial representational redescription, and as evidence of a more complex relationship between behaviour and explanation than predicted by the RRM, with implications for the model’s future use as well as for our understanding of representational change during problem-solving.
Attraction Between Like-Charge Surfaces in Polar Mixtures
Creators: name: Samin, Sela
name: Tsori, Yoav
Publisher: name: arXiv
Year: 2011
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: We examine the force between two charged surfaces immersed in aqueous mixtures having a coexistence curve. For a homogeneous water-poor phase, as the distance between the surfaces is decreased, a water-rich phase condenses at a distance $D_t$ in the range 1-100nm. At this distance the osmotic pressure can become negative leading to a long-range attraction between the surfaces. The osmotic pressure vanishes at a distance $D_e
description: 6 pages, 6 figures
Crystal structure identification with 3D convolutional neural networks with application to high-pressure phase transitions in SiO$_2$
Creators: name: Erhard, Linus C.
name: Utt, Daniel
name: Klomp, Arne J.
name: Albe, Karsten
Publisher: name: arXiv
Year: 2024
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Efficient, reliable and easy-to-use structure recognition of atomic environments is essential for the analysis of atomic scale computer simulations. In this work, we train two neuronal network (NN) architectures, namely PointNet and dynamic graph convolutional NN (DG-CNN) using different hyperparameters and training regimes to assess their performance in structure identification tasks of atomistic structure data. We show benchmarks on simple crystal structures, where we can compare against established methods. The approach is subsequently extended to structurally more complex SiO$_2$ phases. By making use of this structure recognition tool, we are able to achieve a deeper understanding of the crystallization process in amorphous SiO$_2$ under shock compression. Lastly, we show how the NN based structure identification workflows can be integrated into OVITO using its python interface.
XVII МЕЖДУНАРОДНАЯ НАУЧНО-ПРАКТИЧЕСКАЯ КОНФЕРЕНЦИЯ «Развитие науки и практики в глобально меняющемся мире в условиях рисков» http://nauka20-35.ru/Conferences#
Creators: name: ООО "Институт развития образования и консалтинга"
Publisher: name: ООО "Институт развития образования и консалтинга"
Year: 2023

description: XVII МЕЖДУНАРОДНАЯ НАУЧНО-ПРАКТИЧЕСКАЯ КОНФЕРЕНЦИЯ «Развитие науки и практики в глобально меняющемся мире в условиях рисков» http://nauka20-35.ru/Conferences#
Дефекты сердечников турбогенераторов и работы по предупреждению их отказов
Creators: name: Владимировна, Шевченко Валентина
Publisher: name: Zenodo
Year: 2016
Subjects: электрические машины
турбогенераторы
ТГ
отказы ТГ
классификация дефектов ТГ
экономический эффект

description: На русском: [Шевченко В.В. Дефекты сердечников турбогенераторов и работы по предупреждению их отказов // Тезисы докладов 24-й международной научно-практической конференции "Информационные технологии: наука, техника, технология, образование, здоровье" (MicroCAD-2016), 18-20 мая 2016 года, Харьков (ISSN 2222-2944), часть 2, cекция 9 "Электромеханическое и электрическое преобразование энергии". -  Украина, Харьков: НТУ "ХПИ", 2016. - С. 125. https://doi.org/10.5281/zenodo.2594741]

Ключевые слова: электрические машины, турбогенераторы, ТГ, отказы ТГ, классификация дефектов ТГ, экономический эффект.

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Many-particle mechanics with D(2,1;alpha) superconformal symmetry
Creators: name: Krivonos, Sergey
name: Lechtenfeld, Olaf
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: We overcome the barrier of constructing N=4 superconformal models in one space dimension for more than three particles. The D(2,1;alpha) superalgebra of our systems is realized on the coordinates and momenta of the particles, their superpartners and one complex pair of harmonic variables. The models are determined by two prepotentials, F and U, which must obey the WDVV and a Killing-type equation plus homogeneity conditions. We investigate permutation-symmetric solutions, with and without translation invariance. Models based on deformed A_n and BCD_n root systems are constructed for any value of alpha, and exceptional F_n-type and super root systems admit solutions as well. Translation-invariant mechanics occurs for any number of particles at alpha=-1/2 (osp(4|2) invariance as a degenerate limit) and for four particles at arbitrary alpha (three series).
description: 1+12 pages, no figures; v2: two refs added, typos corrected, version published in JHEP; v3: minor correction to (3.8) & (3.10)
Specialization in policing behaviour among workers in the ant Pachycondyla inversa
Creators: name: van Zweden, Jelle S.
name: Fürst, Matthias A.
name: Heinze, Jürgen
name: D'Ettorre, Patrizia
Publisher: name: Universität Regensburg
Year: 2007
Subjects: subject: division of labour; worker reproduction; worker policing; egg eating; aggression
subject: 570 Biowissenschaften, Biologie
subject: 590 Tiere (Zoologie)
subject: Aggression
subject: Animals
subject: Ants/physiology
subject: Behavior, Animal
subject: Conflict (Psychology)
subject: Female
subject: Male
subject: Ovary/growth & development
subject: Ovum
subject: Reproduction
subject: FOS: Medical biotechnology
subject: Social Behavior

description: Most animal societies are non-clonal and thus subject to conflicts. In social insects, conflict over male production can be resolved by worker policing, i.e. eating of worker-laid eggs (WLE) or aggression towards reproductive workers. All workers in a colony have an interest in policing behaviour being expressed, but there can be asymmetries among workers in performing the actual behaviour. Here, we show that workers of the ant Pachycondyla inversa specialize in policing behaviour. In two types of behavioural assays, workers developed their ovaries and laid eggs. In the first experiment, reproductive workers were introduced into queenright colonies. In the second experiment, WLE were introduced. By observing which individuals policed, we found that aggressive policing was highly skewed among workers that had opportunity to police, and that a similar tendency occurred in egg policing. None of the policing workers had active ovaries, so that policing did not incur a direct selfish benefit to the policer. This suggests that policing is subject to polyethism, just like other tasks in the colony. We discuss several hypotheses on the possible causes of this skew in policing tasks. This is the first non-primate example of specialization in policing tasks without direct selfish interests.
Integrality of the Chern character in small codimension
Creators: name: Haution, Olivier
Publisher: name: arXiv
Year: 2011
Subjects: subject: Algebraic Geometry (math.AG)
subject: K-Theory and Homology (math.KT)
subject: FOS: Mathematics
subject: 14C40, 14C15

description: We prove an integrality property of the Chern character with values in Chow groups. As a consequence we obtain, for a prime number p, a construction of the p-1 first homological Steenrod operations on Chow groups modulo p and p-primary torsion, over an arbitrary field. We provide applications to the study of correspondences between algebraic varieties.
description: Correct some typos; add an appendix extending the results to schemes of finite type over a regular base
Data mining in the spectro-microscopic analysis of complex material
Creators: name: Tavassoli, Najmeh
Publisher: name: University of British Columbia
Year: 2017

description: Vibrational spectroscopy has received significant interest in last decades as a robust, rapid, and cost-effective alternative to the traditional wet-chemical methods employed by various industries. The spectra of complex materials may contain some components with a low concentration, whose information is buried within a major peak of another component. These small hidden peaks contain critical information in some analysis. This thesis aims to develop novel data mining methods to improve the quality of data, select its essential features, and finally build prediction models. The pulp industry offers one example in which spectroscopy offers attractive advantages as an on-line method for optimizing manufacturing. While spectroscopic techniques are inherently sensitive to many of properties of interest to the pulp industry, they are potentially sensitive to provide features uncorrelated with physical properties of pulp; which could hinder the development of robust prediction models. To overcome this challenge, we introduced Template Oriented Genetic Algorithm (TOGA). TOGA is aimed to establish significant features to assign predictors according to a template determined to minimize prediction variance in a calibration space. It was found that TOGA significantly improved the prediction accuracy of certain pulp properties compared to those without undergoing these data processing techniques. Near Infrared (NIR) is the most well-known spectroscopy technique which has been successfully applied to pulp industry. However, broad overtone NIR absorption band makes discerning of signature features a difficult process. We showed that a combination of DWT and Orthogonal Signal Correction improved accuracy of prediction models built based on pulp NIR spectra.In the second part of this thesis, a combined technique of interferometric scattering microscopy (iSCAT) and Raman spectroscopy was used to study the dynamics of gold-nanoparticle cellular uptake in cancer and normal cells model. Images derived from the study of these complex samples are heterogeneous which poses a challenge on true quantification and identification of the structure and components of a cell. To address this challenge, we used DWT to remove the out-of-focus and uncorrelated features from the original iSCAT images. This would make a true 3D volume of a cell and a precise track of AuNP internalizing a cell.
The influence of hybridization on colony structure in the ant species Temnothorax nylanderi and T. crassispinus
Creators: name: Pusch, K.
name: Heinze, J.
name: Foitzik, S.
Publisher: name: Universität Regensburg
Year: 2006
Subjects: subject: Contact zone; sibling species; hybridization; reproductive investment
subject: 570 Biowissenschaften, Biologie
subject: 590 Tiere (Zoologie)

description: The parapatric sibling ant species Temnothorax nylanderi and T. crassispinus hybridize in the contact zone in the Franconian Jura, Southern Germany. Aim of our study was to investigate the impact of hybridization on colony composition and fitness. We classified colonies as either ‘pure’ or containing hybrids by determining their allozyme pattern at GPI, an enzyme that is fixed for different alleles in the two parental species, and quantified their reproductive output. Most colonies with hybrid workers had a T. crassispinus queen. Colonies with heterozygous, hybrid workers produced more young workers than colonies of the parental species but similar numbers of male and female sexuals. Female sexuals from colonies with heterozygous workers had a significantly lower weight than female sexuals from pure colonies. Only a single reproductive queen was found to be heterozygous, suggesting reduced fitness of hybrid queens. As in the parental species, hybrid colonies appear to be frequently taken over by alien queens, which obscures the genetic colony structure.
Recovery Rates in investment-grade pools of credit assets: A large deviations analysis
Creators: name: Spiliopoulos, Konstantinos
name: Sowers, Richard B.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Risk Management (q-fin.RM)
subject: Probability (math.PR)
subject: FOS: Economics and business
subject: FOS: Mathematics
subject: 60F05, 60F10 and 91G40

description: We consider the effect of recovery rates on a pool of credit assets. We allow the recovery rate to depend on the defaults in a general way. Using the theory of large deviations, we study the structure of losses in a pool consisting of a continuum of types. We derive the corresponding rate function and show that it has a natural interpretation as the favored way to rearrange recoveries and losses among the different types. Numerical examples are also provided.
description: 27 Pages, 3 Figures
Mating success and potential male-worker conflict in a male-dimorphic ant
Creators: name: Schrempf, Alexandra
name: Darrouzet, Eric
name: Heinze, Jürgen
Publisher: name: Universität Regensburg
Year: 2007
Subjects: subject: 570 Biowissenschaften, Biologie
subject: 590 Tiere (Zoologie)
subject: Animals
subject: Ants/genetics
subject: Female
subject: Longevity
subject: Male
subject: Reproduction
subject: FOS: Medical biotechnology
subject: Sex Characteristics
subject: Sexual Behavior, Animal

description: BACKGROUND: Males of many species adjust their reproductive tactics with regard to their condition and status. For example, large males may develop weapons and fight for access to females, whereas small or undernourished males do not express costly weapons or ornaments and sneak copulations. Different condition-dependent reproductive tactics may be associated with unequal average fitness, but the tactic chosen by a given male under given circumstances is thought to result in the highest possible fitness return.The ant species Cardiocondyla obscurior exhibits an environment-controlled polymorphism of docile, winged males and aggressive "ergatoid" males. Ergatoid males, which can replenish their sperm supply throughout their lives, engage in lethal fighting, and attempt to monopolize all female sexuals available in their nests, were previously assumed to gain higher lifetime reproductive success than the peaceful, winged males, which disperse to mate away from the nest and whose spermatogenesis is limited to the first days of adult life. However, precise data on male mating success have as yet not been available.Here, we compare the average mating success of the two male morphs, taking the high mortality rate of immature ergatoid males into account. Because individuals in insect societies may have opposing interests about their own development, we also investigate whether the interests of male larvae coincide with those of the workers and the rest of the society. RESULTS: When the survival probability of males is taken into account, winged males are more likely to mate multiply and in consequence have a higher estimated average mating success than ergatoid males. Therefore, male larvae are expected to prefer developing into winged instead of ergatoid adults. CONCLUSION: Though male larvae can expect a higher average mating success when developing into winged males, most colonies produce only ergatoid males under standard conditions. This might point at a novel type of potential kin conflict within the social insect colony. Because workers in insect societies usually control male larval development, ergatoid male production under normal conditions probably reflects the optimal allocation strategy of workers to maximise their inclusive fitness.
Dynamics of sperm transfer in the ant Leptothorax gredleri
Creators: name: Oppelt, Angelika
name: Heinze, Jürgen
Publisher: name: Universität Regensburg
Year: 2007
Subjects: subject: Reproductive biology; Mating; Spermatophore; Spermatheca; Spermathecal duct; Formicidae
subject: 570 Biowissenschaften, Biologie
subject: 590 Tiere (Zoologie)
subject: Animals
subject: Ants/physiology
subject: Female
subject: Fertilization/physiology
subject: Male
subject: Spermatogonia/physiology
subject: Spermatozoa/physiology

description: Mating tactics differ remarkably between and within species of social Hymenoptera (bees, wasps, ants) concerning, e.g., mating frequencies, sperm competition, and the degree of male sperm limitation. Although social Hymenoptera might, therefore, potentially be ideal model systems for testing sexual selection theory, the dynamics of mating and sperm transfer have rarely been studied in species other than social bees, and basic information needed to draw conclusions about possible sperm competition and female choice is lacking. We investigated sperm transfer in the ant Leptothorax gredleri, a species in which female sexuals attract males by "female calling." The analysis of 38 female sexuals fixed immediately or up to 7 days after copulation with a single male each revealed that the sperm is transferred into the female bursa copulatrix embedded in a gelatinous mass, presumably a spermatophore. Sperm cells rapidly start to migrate from the tip of the spermatophore towards the spermatheca, but transfer is drastically slowed down by an extreme constriction of the spermathecal duct, through which sperm cells have to pass virtually one by one. This results in the spermatheca being filled only between one and several hours after mating. During this time, the posterior part of the spermatophore seals the junction between bursa copulatrix and spermathecal duct and prevents sperm loss. The prolonged duration of sperm transfer might allow female sexuals to chose between ejaculates and explain previously reported patterns of single paternity of the offspring of multiply mated queens.
Higher Lie algebra actions on Lie algebroids
Creators: name: Zambon, Marco
name: Zhu, Chenchang
Publisher: name: arXiv
Year: 2010
Subjects: subject: Differential Geometry (math.DG)
subject: Category Theory (math.CT)
subject: Symplectic Geometry (math.SG)
subject: FOS: Mathematics
subject: 53D17, 58A50, 18D35

description: We consider a simple instance of action up to homotopy. More precisely, we consider strict actions of DGLAs in degrees -1 and 0 on degree 1 NQ-manifolds. In a more conventional language this means: strict actions of Lie algebra crossed modules on Lie algebroids. When the action is strict, we show that it integrates to group actions in the categories of Lie algebroids and Lie groupoids (i.e. actions of LA-groups and 2-groups). We perform the integration in the framework of Mackenzie's doubles.
description: 29 pages. Presentation improved. Sections 1.3 and 4 have been removed (see arXiv:1202.1378)
Measuring the dynamic thermal expansivity of molecular liquids near the glass transition
Creators: name: Niss, Kristine
name: Gundermann, Ditte
name: Christensen, Tage
name: Dyre, Jeppe C.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: Based on previous works on polymers by Bauer et al. [Phys, Rev. B (2000)], this paper describes a capacitative method for measuring the dynamical expansion coefficient of a viscous liquid. Data are presented for the glass-forming liquid tetramethyl tetraphenyl trisiloxane (DC704) in the ultraviscous regime. Compared to the method of Bauer et al. the dynamical range has been extended by making time-domain experiments and by making very small and fast temperature steps. The modelling of the experiment presented in this paper includes the situation where the capacitor is not full because the liquid contracts when cooling from room temperature down to around the glass-transition temperature, which is relevant when measuring on a molecular liquid rather than polymer.
Ground states of semi-relativistic Pauli-Fierz and no-pair Hamiltonians in QED at critical Coulomb coupling
Creators: name: Könenberg, Martin
name: Matte, Oliver
Publisher: name: arXiv
Year: 2011
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences
subject: 81Q10, 47B25

description: We consider the semi-relativistic Pauli-Fierz Hamiltonian and a no-pair model of a hydrogen-like atom interacting with a quantized photon field at the respective critical values of the Coulomb coupling constant. For arbitrary values of the fine-structure constant and the ultra-violet cutoff, we prove the existence of normalizable ground states of the atomic system in both models. This complements earlier results on the existence of ground states in (semi-)relativistic models of quantum electrodynamics at sub-critical coupling by E. Stockmeyer and the present authors. Technically, the main new achievement is an improved estimate on the spatial exponential localization of low-lying spectral subspaces yielding uniform bounds at large Coulomb coupling constants. In the semi-relativistic Pauli-Fierz model our exponential decay rate given in terms of the binding energy reduces to the one known from the electronic model when the radiation field is turned off. In particular, an increase of the binding energy due to the radiation field is shown to improve the localization of ground states.
description: Revised second version providing optimized exponential decay rates for the semi-relativistic Pauli-Fierz model; see Theorem 4.5 and Remark 4.7. The revised manuscript is accepted for publication in the Journal of Operator Theory. 25 pages