bluuebunny/crossref_metadata_2025 huggingface dataset:
The Empire of Tamerlane as an Adaptation of the Mongol Empire: An answer to David Morgan, “The Empire of Tamerlane: An Unsuccessful Re-Run of the Mongol State?”
Authors: MANZ BEATRICE F.
Published: May 2016

I write this article in the spirit of the Persian poetic tradition, in which an answer to an earlier work takes off from the original and charts its own course. I will suggest that Tamerlane's recreation of the Mongol Empire was symbolic, and was part of his successful creation of a regional state which was at once Turco-Mongolian and Perso-Islamic. His experiment was continued and elaborated by his successors, and the resulting state provided a highly useful model for later dynasties in the Middle East and Central Asia.

Through my long engagement with Mongols and Turks, David Morgan's influence and aid have been a constant advantage and his friendship a recurring pleasure. Our acquaintance began in 1987 with a kind letter he sent me after reading the manuscript forThe Rise and Rule of Tamerlanefor the Cambridge University Press. Since then I have profited from his scholarship, have used his two books to teach generations of students, and have called on him for uncountable letters of recommendation, always generously given. I also want to thank David for asking me to write the Mongol chapter for theNew Cambridge History of Islam, and thus attracting me into the Mongol period. It may seem odd to express my gratitude by writing an answer to David's article which is not entirely in agreement with his conclusions. I trust in the well-known openness of his mind and assume that he will take this in the spirit in which it is offered, as the continuation of many years of discussion.
Political Metaphors and Concepts in the Writings of an Eleventh-Century Sunni Scholar, Abū al-Ma‛ālī al-Juwaynī (419 – 478/1028 – 1085)
Authors: ANJUM OVAMIR
Published: May 2016

This article investigates political vocabulary and metaphor in the writings of al-Juwayni (d. 1085) to bring out the commitments and presuppositions of premodern Islamic political tradition and raises the question of their compatibility with those of the modern nation-state.
Al-Afḍal the Son of Saladin and His Reputation
Authors: HAWTING GERALD
Published: May 2016

The period following the death of Saladin (589/1193) was a formative one in the history of the Ayyūbid empire. It saw the eventual establishment of Saladin's younger brother Sayf al-Dīn al-Malik al-ʿĀdil as the acknowledged sovereign of the various territories ruled by members of the Ayyūbid family, overturning the succession arrangements that Saladin had put into place; and it established modes of behaviour to be followed, mutatis mutandis, following the death of a leading Ayyūbid ruler on future occasions. The main loser in al-ʿĀdil's rise to the sultanate was Saladin's eldest son, al-Malik al-Afḍal ʿAlī, whom some have written off as an incompetent failure. In this paper for David Morgan, for many years my trusted colleague in the SOAS History Department, I suggest that that judgment on al-Afḍal is open to appeal.
Segmentation Method of Time-Lapse Microscopy Images with the Focus on Biocompatibility Assessment
Authors: Soukup Jindřich , Císař Petr , Šroubek Filip
Published: May 2016

Biocompatibility testing of new materials is often performed in vitro by measuring the growth rate of mammalian cancer cells in time-lapse images acquired by phase contrast microscopes. The growth rate is measured by tracking cell coverage, which requires an accurate automatic segmentation method. However, cancer cells have irregular shapes that change over time, the mottled background pattern is partially visible through the cells and the images contain artifacts such as halos. We developed a novel algorithm for cell segmentation that copes with the mentioned challenges. It is based on temporal differences of consecutive images and a combination of thresholding, blurring, and morphological operations. We tested the algorithm on images of four cell types acquired by two different microscopes, evaluated the precision of segmentation against manual segmentation performed by a human operator, and finally provided comparison with other freely available methods. We propose a new, fully automated method for measuring the cell growth rate based on fitting a coverage curve with the Verhulst population model. The algorithm is fast and shows accuracy comparable with manual segmentation. Most notably it can correctly separate live from dead cells.
Is wheat germ grass detrimental during radiotherapy?: a hypothesis
Authors: Kataria Tejinder , Gupta Deepak , Sambasivam Sasikumar , Vishnu Nisha T. , Goyal Shikha , Bisht Shyam Singh , Basu Trinanjan , Abhishek Ashu , Narang Kushal , Banerjee Susovan
Published: May 2016

Background

Antioxidant therapies to control oxidative damage have already attracted worldwide attention in recent years. Extensive studies on phytochemicals in cell culture system and animal models have provided a wealth of information on the mechanism by which such nutraceuticals show their beneficial effect. Nutraceuticals include plant-derived factors (phytochemicals) and factors derived from animal sources as well as from microbial sources. The activities of nutraceuticals are broad and include antioxidation, modulation of enzyme activity and modification of natural hormonal activity (agonist or antagonist) to act as a precursor for one or more beneficial molecules. Antioxidants scavenge free radicals that cause cell damage. Antioxidant consumption during radiotherapy and its effects are still controversial. Some studies suggest that antioxidant supplementation during chemotherapy or radiotherapy may be beneficial and some, harmful. Wheat grass is rich in superoxide dismutase, an antioxidant enzyme. Radiotherapy causes tumour cell kill via activation of reactive oxygen species, specifically by the hydroxyl radical and needs the reactive species for effective tumour control. Wheat grass which is rich in free radical scavengers can interfere with reactive oxygen species generated by radiation for tumour cell kill and can be detrimental to the therapy per se.

Purpose

To hypothesise if the antioxidant properties of wheat grass could influence tumour activity, the effects of radiation therapy on tumour cells can be nullified when wheat grass is taken during radiotherapy.
Konservative und operative Behandlung der chronischen Rhinosinusitis
Authors: Friedrich Hergen , Negoias Simona , Caversaccio Marco Domenico
Published: May 2016

Zusammenfassung: Die chronische Rhinosinusitis ist ein häufiges, komplexes Krankheitsbild, welches mit ausgeprägten Therapiekosten und deutlicher Beeinträchtigung der Lebensqualität assoziiert ist. Das EPOS2012 beinhaltet den aktuellen Standard für das Management von Patienten mit chronischer Rhinosinusitis für beide definierten Krankheitsentitäten: mit und ohne Polypen. Die Diagnose besteht in der Kombination zwischen Anamnese und endoskopischen oder CT-bildmorphologischen Befunden. Die Therapie einer chronischen Rhinosinusitis sollte sich zum einen an den Beschwerden des Patienten orientieren als auch an dem endoskopischen Befund. Im Zentrum der medikamentösen Therapie der chronischen Rhinosinusits mit und ohne Polypen steht die topische Applikation von Steroiden begleitet von Salzwasserspülung. Bei Ausbleiben von Besserung oder schwereren Formen steht eine Anpassung der Cortisontherapie oder die Operation im Vordergrund. Die funktionelle endoskopische Sinusoperation ist der aktuelle Goldstandard der Nasennebenhöhlenchirurgie. Ziel dieser ist die möglichst schonende Eröffnung der Nasennebenhöhlen um hier eine adäquate und zielführende Belüftung zu ermöglichen und eine Applikation von topischen Medikamenten an der erkrankten Schleimhaut sicherzustellen.
Apparative und operative Rehabilitation des Hörvermögens
Authors: Stieger Christof , Bodmer Daniel , Brand Yves
Published: May 2016

Zusammenfassung: Menschen mit einer Hörminderung sind im klinischen Alltag häufig. Sowohl Kinder als auch Erwachsene können von einer Hörminderung betroffen sein. Unabhängig vom Alter hat eine Hörstörung einen entscheidenden Einfluss auf die Lebensqualität eines Menschen. Glücklicherweise stehen zahlreiche Möglichkeiten einer apparativen und operativen Rehabilitation des Hörvermögens zu Verfügung. Ziel dieser Arbeit ist es, die häufigsten Rehabilitationsmassnahmen für das Gehör vorzustellen. Diese umfassen rein apparative Massnahmen, wie ein konventionelles Hörgerät. Oder aber sie beschreiben rein operative Massnahmen wie zum Beispiel das Einsetzen einer passiven Prothese bei der Verknöcherung des Stapes an der Fussplatte infolge einer Otosklerose. Des Weiteren gibt es Rehabilitatonsmöglichkeiten bei welchen eine Operation mit einer apparativen Massnahme kombiniert wird. Dies ist der Fall bei einem knochenverankertem Hörgerät, einem aktiven Mittelohrimplantat oder bei einem Cochlea Implantat. Der Schwerpunkt dieses Artikels liegt in der Darstellung von exemplarischen klinischen Beispielen der diskutierten Gehörrehabilitation.
Abklärung und Behandlung von Schnarchen und obstruktiver Schlafapnoe
Authors: Knaus Christoph
Published: May 2016

Zusammenfassung: Der Übergang eines einfachen Schnarchens (Rhonchopathie) zur obstruktiven Schlafapnoe ist fliessend. Die einfache Rhonchopathie ohne gesundheitliche Folgen ist mit einer Prävalenz von bis zu 60 % sehr hoch. Im Gegensatz zur einfachen Rhonchopathie ist die obstruktive Schlafapnoe mit teilweise schwerwiegenden Folgeerkrankungen assoziiert. Ihre Häufigkeit in der Gesamtbevölkerung wird auf 2 – 5 % geschätzt. In der folgenden Übersichtsarbeit werden unterschiedliche diagnostische Methoden und die sich daraus ergebenden therapeutischen Konsequenzen zusammengefasst. Neben der Standardtherapie mit der nächtlichen CPAP-Therapie werden sowohl konservative als auch operative Therapieoptionen beleuchtet.
Langzeitfolgen der Radiochemotherapie bei Kopf-Hals-Tumoren
Authors: Schoch Manuel , Broglie Däppen Martina , Henke Guido , Stöckli Sandro
Published: May 2016

Zusammenfassung: Die häufigsten Tumore im Kopf-Hals-Bereich sind Plattenepithelkarzinome im Pharynx, der Mundhöhle und im Larynx. Sie können je nach Tumorlokalisation und -ausdehnung mittels primärer Radio(chemo)therapie oder alleiniger Chirurgie oder einer Kombination beider Modalitäten behandelt werden. Dieser Artikel beleuchtet die Entwicklungen im Bereich der Strahlentherapie und gibt einen Überblick über deren häufigsten Langzeitkomplikationen und ihre Einflussfaktoren.
Psychometric Properties of Drinking Motives Questionnaire-Revised	(DMQ-R) in Spanish Adolescents
Authors: Mezquita Laura , Ibáñez Manuel I. , Moya-Higueras Jorge , Villa Helena , Arias Bárbara , Fañanás Lourdes , Ortet Generós
Published: May 2016

Abstract. The Drinking Motives Questionnaire-Revised (DMQ-R; Cooper, 1994 ) is the most widely used questionnaire to assess drinking motives. This research aimed to adapt and study the validity and reliability of the Spanish DMQ-R and its short form in a sample of adolescents. We assessed 504 drinkers at Time 1 (T1, Mage = 14.15, SD = 0.60, 52.38% female), of whom 238 participated in a 1-year follow-up (T2, Mage = 15.05, SD = 0.54, 58.82% female). They completed the DMQ-R at T1, the alcohol use measure at T1 and T2, and the alcohol-related problems questionnaire at T2. We performed Confirmatory Factor Analyses (CFAs) to test the structure validity of the questionnaire, Cronbach’s alphas to test the internal consistencies of the scales, and path analyses to test the concurrent and predictive validity of motives on alcohol outcomes. CFA indicated that the short form of the 4-factor model best fitted the data. Cronbach’s alphas were .70 or higher. Direct effects of the path analysis showed that social motives cross-sectionally predicted alcohol use, while coping motives prospectively predicted alcohol-related problems. Indirect effects showed that social motives prospectively predicted alcohol use and problems. To conclude, the DMQ-R short form appears to be reliable and valid to assess drinking motives among Spanish adolescents.
Does the Factor Structure of the Brief COPE Fit Different Types of Traumatic Events?
Authors: Wang Ashley Wei-Ting , Cheng Chung-Ping , Chang Cheng-Shyong , Chen Dar-Ren , Chen Shou-Tung , Shieh Vincent , Lo Angela , Hsu Wen-Yau
Published: May 2016

Abstract. The current study aims to explore the likelihood of there being a higher-order factorial model of the Brief COPE ( Carver, 1997 ) that is equally appropriate and valid for different traumatic groups (i.e., breast cancer patients and female flood survivors) at 3–4 months after the traumatic event. Both groups of participants include 180 survivors. Five factorial models for the Brief COPE were identified when reviewing the literature, and model comparisons were made by conducting confirmatory factor analyses (CFAs). The three dimensions of the Brief COPE posited by Litman (2006) and Gutiérrez, Peri, Torres, Caseras, and Valdés (2007) , namely self-sufficient coping, socially-supported coping, and avoidant coping, were supported in both traumatic populations. Tests of measurement invariance generally supported invariance (factor form, factor loadings, item intercepts, error variances, factor variances, and covariances) across groups, implying that groups perceive the latent factors in the same way and the higher-order coping across different traumatic groups is meaningful. Moreover, the relationship between the three higher-order coping factors and variables of psychological adjustment was examined. Generally, different relationships between the subtypes of coping and the outcomes of adaptation existed between female flood survivors and breast cancer patients. Further theoretical and practical implications for these relationships are discussed.
Development of the Teacher Attitudes Towards Self-Regulated Learning	Scale
Authors: Steinbach Julia , Stoeger Heidrun
Published: May 2016

Abstract. We describe the development and validation of an instrument for measuring the affective component of primary school teachers’ attitudes towards self-regulated learning. The questionnaire assesses the affective component towards those cognitive and metacognitive strategies that are especially effective in primary school. In a first study (n = 230), the factor structure was verified via an exploratory factor analysis. A confirmatory factor analysis with data from a second study (n = 400) indicated that the theoretical factor structure is appropriate. A comparison with four alternative models identified the theoretically derived factor structure as the most appropriate. Concurrent validity was demonstrated by correlations with a scale that measures the degree to which teachers create learning environments that enable students to self-regulate their learning. Retrospective validity was demonstrated by correlations with a scale that measures teachers’ experiences with self-regulated learning. In a third study (n = 47), the scale’s concurrent validity was tested with scales measuring teachers’ evaluation of the desirability of different aspects of self-regulated learning in class. Additionally, predictive validity was demonstrated via a binary logistic regression, with teachers attitudes as predictor on their registration for a workshop on self-regulated learning and their willingness to implement a seven-week training program on self-regulated learning.
The topography of mutational processes in breast cancer genomes
Authors: Morganella Sandro , Alexandrov Ludmil B. , Glodzik Dominik , Zou Xueqing , Davies Helen , Staaf Johan , Sieuwerts Anieta M. , Brinkman Arie B. , Martin Sancha , Ramakrishna Manasa , Butler Adam , Kim Hyung-Yong , Borg Åke , Sotiriou Christos , Futreal P. Andrew , Campbell Peter J. , Span Paul N. , Van Laere Steven , Lakhani Sunil R. , Eyfjord Jorunn E. , Thompson Alastair M. , Stunnenberg Hendrik G. , van de Vijver Marc J. , Martens John W. M. , Børresen-Dale Anne-Lise , Richardson Andrea L. , Kong Gu , Thomas Gilles , Sale Julian , Rada Cristina , Stratton Michael R. , Birney Ewan , Nik-Zainal Serena
Published: May 2016

Somatic mutations in human cancers show unevenness in genomic distribution that correlate with aspects of genome structure and function. These mutations are, however, generated by multiple mutational processes operating through the cellular lineage between the fertilized egg and the cancer cell, each composed of specific DNA damage and repair components and leaving its own characteristic mutational signature on the genome. Using somatic mutation catalogues from 560 breast cancer whole-genome sequences, here we show that each of 12 base substitution, 2 insertion/deletion (indel) and 6 rearrangement mutational signatures present in breast tissue, exhibit distinct relationships with genomic features relating to transcription, DNA replication and chromatin organization. This signature-based approach permits visualization of the genomic distribution of mutational processes associated with APOBEC enzymes, mismatch repair deficiency and homologous recombinational repair deficiency, as well as mutational processes of unknown aetiology. Furthermore, it highlights mechanistic insights including a putative replication-dependent mechanism of APOBEC-related mutagenesis.
Nature of surface carbon species and pathways of their formation in the heterogeneously catalysed acetoxylation of toluene
Authors: Reining S. , Kondratenko E. V. , Bentrup U. , Radnik J. , Kalevaru V. N. , Martin A.
Published: May 2016

The origins of surface carbon species in the acetoxylation of toluene to benzyl acetate over Pd–Sb/TiO2 catalyst and their formation pathways were systematically investigated.
Sorption selectivity of birnessite particle edges: a d-PDF analysis of Cd(ii) and Pb(ii) sorption by δ-MnO2and ferrihydrite
Authors: van Genuchten Case M. , Peña Jasquelin
Published: May 2016

Birnessite minerals (layer-type MnO2), which bear both internal (cation vacancies) and external (particle edges) metal sorption sites, are important sinks of contaminants in soils and sediments.
Recovery of phycobiliproteins from the red macroalga Gracilaria sp. using ionic liquid aqueous solutions
Authors: Martins Margarida , Vieira Flávia A. , Correia Isabel , Ferreira Rute A. S. , Abreu Helena , Coutinho João A. P. , Ventura Sónia P. M.
Published: May 2016

Bioactive compounds extracted from natural renewable sources have attracted increased interest from both industry and academia.
In situ formation of bromobenzene diazonium ions and their spontaneous reaction with carbon-coated LiFePO4 in organic media
Authors: Delaporte Nicolas , Zaghib Karim , Bélanger Daniel
Published: May 2016

In this study, the diazotization of bromoaniline in the presence of carbon-coated LiFePO4 and the grafting of bromobenzene moieties are investigated.
New cyclometalated Ir(iii) complexes with bulky ligands with potential applications in LEC devices: experimental and theoretical studies of their photophysical properties
Authors: Dreyse Paulina , González Iván , Cortés-Arriagada Diego , Ramírez Oscar , Salas Ignacio , González Andrea , Toro-Labbe Alejandro , Loeb Bárbara
Published: May 2016

The synthesis and the electrochemical, photoluminescent and electroluminescent properties is reported for two new Ir(iii) cyclometalated complexes described as [Ir(F2ppy)2L1](PF6) and [Ir(F2ppy)2L2](PF6).
The role of crystallinity of the Nb2O5 blocking layer on the performance of dye-sensitized solar cells
Authors: Suresh Sankarapanicker , Deepak Thrithamarassery Gangadharan , Ni Chengsheng , Sreekala Chandrasekharan Nair Omanaamma , Satyanarayana Malladi , Nair A. Sreekumaran , Pillai Vellara Pappukkuty Pillai Mahadevan
Published: May 2016

Role of Nb2O5 amorphous/crystalline blocking layers were investigated in DSSCs and a theoretical explanation was deduced from transient voltage decay analysis.
The application of double click to synthesize a third-order nonlinear polymer containing donor–acceptor chromophores
Authors: Wang Dong , Guo Qingsen , Gao Hong , Yang Zhou , Xing Yan , Cao Hui , He Wanli , Wang Huihui , Gu Jianming , Hu Huiying
Published: May 2016

A new linear polymer containing the dialkylaniline-substituted electron-rich alkynes in the side chains was designed and synthesized by copper-catalyzed azide–alkyne cycloaddition (CuAAC).
Hispanic Immigrant Mothers of Young Children With Autism Spectrum Disorders: How Do They Understand and Cope With Autism?
Authors: Ijalba Elizabeth
Published: May 2016

Purpose

This study aimed to understand the experiences of raising a child with autism spectrum disorders (ASD) in a group of Hispanic immigrant mothers. The following 3 aspects were explored: (a) the families' social environments, (b) cultural beliefs on development and autism, and (c) perceptions of bilingualism influencing language choices.

Method

In-depth 3-part phenomenological interviews and thematic analyses were conducted with 22 Hispanic immigrant mothers of preschool children with ASD.

Results

A total of 3 thematic categories emerged: stigmatization and social isolation, preconceptions about developmental milestones and autism, and mothers' reluctance to speak Spanish with their children. A lack of awareness about autism influenced social isolation, and autism was viewed as temporary and associated with fear or sadness. The mothers believed that exposure to 2 languages would increase their children's language difficulties.

Conclusions

Hispanic immigrant mothers raising children with autism were often challenged by immigration status, economic hardship, and advice against using Spanish with their children. Professional training and parent education are needed to facilitate early identification of ASD. Immigrant families should be encouraged to communicate in the home language with their children. Information about ASD should be disseminated through community outreach, home–school connections, and pediatricians, who remain pivotal in informing Hispanic immigrant families.

Supplemental Material

https://doi.org/10.23641/asha.6170258
Remote ischemic Conditioning – endogene Gewebeprotektion und ihre Einsatzmöglichkeiten in der Chirurgie
Authors: Sogorski A. , Harati K. , Kapalschinski N. , Daigeler A. , Hirsch T. , Lehnhardt M. , Goertz O. , Kolbenschlag J.
Published: May 2016

Als Grundlage für Wundheilung und Regeneration nach Operationen kommt der Gewebeperfusion zentrale Bedeutung zu. Ischämien und Reperfusion führen über die Auslösung von Entzündungsreaktionen im Gewebe zu Gewebeschäden bis hin zur Nekrose. Um im Rahmen des perioperativen Managements das Gewebe vor solch schädigenden Einflüssen zu schützen, wurden eine Vielzahl an Konditionierungsverfahren beschrieben. Die wenigsten dieser Verfahren erfüllen jedoch die Forderung nach Wirksamkeit, zeit- und kosteneffektiver Anwendbarkeit und nicht invasiver Anwendung ohne zusätzliche Geräte oder Medikamente. Remote ischemic Conditioning (RIC) stellt eine Möglichkeit der endogenen Gewebekonditionierung dar, welche diese Kriterien erfüllt. Durch kurze wiederholte Zyklen aus Ischämie und Reperfusion eines isolierten vaskulären Territoriums kommt es über die Aktivierung körpereigener Signalwege zu gesteigerter Toleranz gegenüber Minderversorgung und Begrenzung des Reperfusionsschadens im Gewebe auch fernab des eigentlich konditionierten Gebiets. Zur nicht invasiven Applikation der notwendigen Ischämie-/Reperfusionszyklen genügt eine Druckmanschette, die am Oberarm angelegt und wiederholt auf suprasystolische Werte aufgepumpt wird. Die verschiedenen Konzepte des Remote ischemic Pre-, Per- und Postconditioning ermöglichen die Anwendung sowohl im Rahmen von Elektiveingriffen als auch bei Notfallinterventionen. RIC findet, aufbauend auf vielversprechenden experimentellen Studien, zunehmend klinische Anwendung. Neben Studien zur Kardio-, Nephro- und Neuroprotektion liegen auch erste Ergebnisse für den potenziellen Einsatz von RIC in der rekonstruktiven Mikrochirurgie vor. Dieser Artikel soll daher einen Überblick über Entwicklung, Konzepte und beteiligte Mechanismen des RIC mit Schwerpunkt auf den Einsatzmöglichkeiten in der Chirurgie geben.
Colloidal suspensions of C-particles: Entanglement, percolation and microrheology
Authors: Hoell Christian , Löwen Hartmut
Published: May 2016

We explore structural and dynamical behavior of concentrated colloidal suspensions made up by C-shape particles using Brownian dynamics computer simulations and theory. In particular, we focus on the entanglement process between nearby particles for almost closed C-shapes with a small opening angle. Depending on the opening angle and the particle concentration, there is a percolation transition for the cluster of entangled particles which shows the classical scaling characteristics. In a broad density range below the percolation threshold, we find a stretched exponential function for the dynamical decorrelation of the entanglement process. Finally, we study a setup typical in microrheology by dragging a single tagged particle with constant speed through the suspension. We measure the cluster connected to and dragged with this tagged particle. In agreement with a phenomenological theory, the size of the dragged cluster depends on the dragging direction and increases markedly with the dragging speed.
Amplitude hysteresis of the surface reactance of a layered superconductor
Authors: Apostolov S. S. , Bozhko A. A. , Maizelis Z. A. , Sorokina M. A. , Yampol'skii V. A.
Published: May 2016

A new nonlinear electrodynamic phenomenon in layered superconducting slabs irradiated on one side by plane electromagnetic waves in the terahertz range is predicted and studied theoretically. It is shown that the surface reactance of a sample and its reflection coefficient have hysteresis behavior when the amplitude of the incident wave is changed. The analogy between the electrodynamic problem of the electromagnetic field distribution in a superconductor and the mechanical problem of particle motion in a central field is also discussed.
Isotropic rotation vs. shear relaxation in supercooled liquids with globular cage molecules
Authors: Kaseman Derrick C. , Gulbiten Ozgur , Aitken Bruce G. , Sen Sabyasachi
Published: May 2016

The temperature dependence of the rotational dynamics of P4Se3 molecules in the glass-forming molecular liquid P5Se3 is studied using two-dimensional 31P nuclear magnetic resonance spectroscopy. Unlike typical molecular glass-forming liquids, the constituent molecules in the P5Se3 liquid perform rapid isotropic rotation without significant translational diffusion in the supercooled regime and this rotational process shows a decoupling in time scale from shear relaxation by nearly six orders of magnitude at the glass transition. This dynamical behavior of liquid-like rotation and localized translation appears to be universal to glass-forming liquids with high-symmetry globular molecules that are characterized by an underlying thermodynamically stable plastic crystal phase.
Low-temperature magnetic phase transitions in the multiferroic Nd0.9Dy0.1Fe3(BO3)4. Part 1. Transitions induced by magnetic fields directed along the trigonal symmetry axis. Spontaneous transitions with temperature changes
Authors: Zvyagina G. A. , Zhekov K. R. , Bilych I. V. , Kolodyazhnaya M. P. , Zvyagin A. A. , Bludov A. N. , Pashchenko V. A. , Gudim I. A.
Published: May 2016

The elastic and magnetic characteristics of single-crystal Nd0.9Dy0.1Fe3(BO3)4 are studied at low temperatures in zero magnetic field and in external fields H||C3. The temperature dependences of the acoustic mode velocities and the magnetic susceptibility manifest a transition of the magnetic subsystem into a magnetically ordered state and two successive, spontaneous spin-reorientation phase transitions. The possibility of a spontaneous transition into an incommensurate (spiral) magnetic phase in the crystal is discussed. It is shown that an external magnetic field directed along the trigonal axis of the crystal induces a sequence of spin-reorientation phase transitions. An H-T phase diagram (H||C3) is constructed for this compound.
Inverted point-contact spectrum of electron-phonon interactions in arsenic homocontacts
Authors: Khotkevich A. V. , Krasnyi A. S.
Published: May 2016

The point-contact (microcontact) spectra (second derivatives of the current-voltage characteristics) of As/As point homocontacts are measured at liquid helium temperatures. Inversion of the sign of the point-contact spectrum is observed as a result of the destruction of electron localization in the arsenic contacts owing to electron-phonon interactions. The point-contact spectrum contains two major peaks at energies of 10 and 25 meV. The boundary of the single-phonon part of the spectrum corresponds to 34 meV. This agrees with available data on the density of phonon states. Assuming that the inverted point-contact spectrum reflects features of the electro-phonon interaction spectral function, the mean-square frequency of the phonons is calculated and the Debye temperature is estimated.
A secondary diffraction effect and the generation of Scholte–Stoneley acoustic wave on periodically corrugated surface
Authors: Liu Jingfei , Declercq Nico F.
Published: May 2016

When a wideband sound beam is incident onto a periodically corrugated surface, a series of diffraction related phenomena can occur. In this work, we report the observation of a secondary diffraction, which is different from those previously investigated. The search of the physical origin of this newly observed diffraction leads to the discovery of the possibility of generating Scholte–Stoneley waves, inspired by Guo, Margetan, and Thompson's work in sound backscattering from rough surfaces, through a nonconventional energy conversion mechanism: direct coupling of the incident energy with the periodic interface. This mechanism allows for the Scholte–Stoneley wave generation at any angle of incidence, which distinguishes it from the well-known energy conversion mechanism of the diffraction-related phenomena such as acoustic Wood anomaly and backward displacement in which wave generation is highly angle dependent. The findings of this work not only enrich the understanding of the interaction of sound with periodically corrugated structures but also provide a new surface wave generation method for the potential applications in nondestructive evaluation of materials.
A multi-probe thermophoretic soot sampling system for high-pressure diffusion flames
Authors: Vargas Alex M. , Gülder Ömer L.
Published: May 2016

Optical diagnostics and physical probing of the soot processes in high pressure combustion pose challenges that are not faced in atmospheric flames. One of the preferred methods of studying soot in atmospheric flames is in situ thermophoretic sampling followed by transmission electron microscopy imaging and analysis for soot sizing and morphology. The application of this method of sampling to high pressures has been held back by various operational and mechanical problems. In this work, we describe a rotating disk multi-probe thermophoretic soot sampling system, driven by a microstepping stepper motor, fitted into a high-pressure chamber capable of producing sooting laminar diffusion flames up to 100 atm. Innovative aspects of the sampling system design include an easy and precise control of the sampling time down to 2.6 ms, avoidance of the drawbacks of the pneumatic drivers used in conventional thermophoretic sampling systems, and the capability to collect ten consecutive samples in a single experimental run. Proof of principle experiments were performed using this system in a laminar diffusion flame of methane, and primary soot diameter distributions at various pressures up to 10 atm were determined. High-speed images of the flame during thermophoretic sampling were recorded to assess the influence of probe intrusion on the flow field of the flame.
A broadband micro-machined far-infrared absorber
Authors: Wollack E. J. , Datesman A. M. , Jhabvala C. A. , Miller K. H. , Quijada M. A.
Published: May 2016

The experimental investigation of a broadband far-infrared meta-material absorber is described. The observed absorptance is >0.95 from 1 to 20 THz (300–15 μm) over a temperature range spanning 5–300 K. The meta-material, realized from an array of tapers ≈100 μm in length, is largely insensitive to the detailed geometry of these elements and is cryogenically compatible with silicon-based micro-machined technologies. The electromagnetic response is in general agreement with a physically motivated transmission line model.
On the canonical forms of the multi-dimensional averaged Poisson brackets
Authors: Maltsev A. Ya.
Published: May 2016

We consider here special Poisson brackets given by the “averaging” of local multi-dimensional Poisson brackets in the Whitham method. For the brackets of this kind it is natural to ask about their canonical forms, which can be obtained after transformations preserving the “physical meaning” of the field variables. We show here that the averaged bracket can always be written in the canonical form after a transformation of “Hydrodynamic Type” in the case of absence of annihilators of initial bracket. However, in general case the situation is more complicated. As we show here, in more general case the averaged bracket can be transformed to a “pseudo-canonical” form under some special (“physical”) requirements on the initial bracket.
Algorithms for calculating mass-velocity and Darwin relativistic corrections with n-electron explicitly correlated Gaussians with shifted centers
Authors: Stanke Monika , Palikot Ewa , Adamowicz Ludwik
Published: May 2016

Algorithms for calculating the leading mass-velocity (MV) and Darwin (D) relativistic corrections are derived for electronic wave functions expanded in terms of n-electron explicitly correlated Gaussian functions with shifted centers and without pre-exponential angular factors. The algorithms are implemented and tested in calculations of MV and D corrections for several points on the ground-state potential energy curves of the H2 and LiH molecules. The algorithms are general and can be applied in calculations of systems with an arbitrary number of electrons.
Virial series for inhomogeneous fluids applied to the Lennard-Jones wall-fluid surface tension at planar and curved walls
Authors: Urrutia Ignacio , Paganini Iván E.
Published: May 2016

We formulate a straightforward scheme of statistical mechanics for inhomogeneous systems that includes the virial series in powers of the activity for the grand free energy and density distributions. There, cluster integrals formulated for inhomogeneous systems play a main role. We center on second order terms that were analyzed in the case of hard-wall confinement, focusing in planar, spherical, and cylindrical walls. Further analysis was devoted to the Lennard-Jones system and its generalization, the 2k-k potential. For these interaction potentials, the second cluster integral was evaluated analytically. We obtained the fluid-substrate surface tension at second order for the planar, spherical, and cylindrical confinement. Spherical and cylindrical cases were analyzed using a series expansion in the radius including higher order terms. We detected a lnR/R2 dependence of the surface tension for the standard Lennard-Jones system confined by spherical and cylindrical walls, no matter if particles are inside or outside of the hard walls. The analysis was extended to bending and Gaussian curvatures, where exact expressions were also obtained.
Transformation of the critical state in hard superconductors resulting from thermomagnetic avalanches
Authors: Chabanenko V. V. , Kuchuk E. I. , Rusakov V. F. , Abaloszewa I. , Nabiałek A. , Pérez-Rodríguez F.
Published: May 2016

The results of experimental studies of magnetic flux dynamics in finite-size superconductors, obtained using integral and local measurements methods, are presented. Local methods were aimed at clarifying the role of the demagnetizing factor in the dynamic formation of a complex magnetic structure of the critical state of hard superconductors. To understand the reasons for drastic transformation of the magnetic induction, we further analyzed the literature data on the visualization of flux dynamics in the presence of avalanches, obtained by magneto-optical methods. New features in the behavior of the magnetic flux during and after an avalanche were revealed and characterized: two stages in the formation of the magnetic induction distribution inside the avalanche region were established—homogeneous and heterogeneous filling with magnetic flux; the mechanism of inversion of the induction profile; velocity oscillations in the propagating magnetic flux front; transformation of the critical state band near the edge of the sample; and the role of the thermal effects and demagnetizing factor in the dissipative flux dynamics. The generalized information allowed us to present, within the framework of the Bean concept, a model of the transformation of the patterns of magnetic induction in the critical state and superconducting currents in a finite superconductor occurring as a result of flux avalanches in two different regimes—shielding and trapping of magnetic flux.
Phosphorus and carrier density of heavily n-type doped germanium
Authors: Takinai K. , Wada K.
Published: May 2016

The threshold current density of n-type, tensile-strained Ge lasers strongly depends on the electron density. Although optical net gain analyses indicate that the optimum electron density should be on the order of 1 × 1020 cm−3 to get the lowest threshold, it is not a simple task to increase the electron density beyond the mid range of 1019 cm−3. The present paper analyzes the phenomenon where electron density is not proportional to phosphorus donor density, i.e., “saturation” phenomenon, by applying the so-called amphoteric defect model. The analyses indicate that the saturation phenomenon can be well explained by the charge compensation between the phosphorus donors (P+) and doubly negative charged Ge vacancies (V2−).
Simple locking of infrared and ultraviolet diode lasers to a visible laser using a LabVIEW proportional-integral-derivative controller on a Fabry-Perot signal
Authors: Kwolek J. M. , Wells J. E. , Goodman D. S. , Smith W. W.
Published: May 2016

Simultaneous laser locking of infrared (IR) and ultraviolet lasers to a visible stabilized reference laser is demonstrated via a Fabry-Perot (FP) cavity. LabVIEW is used to analyze the input, and an internal proportional-integral-derivative algorithm converts the FP signal to an analog locking feedback signal. The locking program stabilized both lasers to a long term stability of better than 9 MHz, with a custom-built IR laser undergoing significant improvement in frequency stabilization. The results of this study demonstrate the viability of a simple, computer-controlled, non-temperature-stabilized FP locking scheme for our applications, laser cooling of Ca+ ions, and its use in other applications with similar modest frequency stabilization requirements.
Method for measuring settling phenomena by means of frequency domain instrumentation
Authors: D’Apuzzo M. , D’Arco M. , Liccardo A. , Vadursi M.
Published: May 2016

The paper deals with the analysis of settling phenomena that characterize the step response of digital to analog converters, amplifiers, and several other devices. Settling is described by means of a minimal second order model that is suitable to account for the distortion terms recognized in the signal spectrum. An alternative method for dynamic performance assessment of systems characterized by poor settling performance is then proposed. Thanks to the use of high bandwidth spectrum analyzers, the proposed method overtakes the limits characterizing the measurement approaches based on the use of time-domain instruments in the presence of modern ultra-wideband systems.
Fractality of pulsatile flow in speckle images
Authors: Nemati M. , Kenjeres S. , Urbach H. P. , Bhattacharya N.
Published: May 2016

The scattering of coherent light from a system with underlying flow can be used to yield essential information about dynamics of the process. In the case of pulsatile flow, there is a rapid change in the properties of the speckle images. This can be studied using the standard laser speckle contrast and also the fractality of images. In this paper, we report the results of experiments performed to study pulsatile flow with speckle images, under different experimental configurations to verify the robustness of the techniques for applications. In order to study flow under various levels of complexity, the measurements were done for three in-vitro phantoms and two in-vivo situations. The pumping mechanisms were varied ranging from mechanical pumps to the human heart for the in vivo case. The speckle images were analyzed using the techniques of fractal dimension and speckle contrast analysis. The results of these techniques for the various experimental scenarios were compared. The fractal dimension is a more sensitive measure to capture the complexity of the signal though it was observed that it is also extremely sensitive to the properties of the scattering medium and cannot recover the signal for thicker diffusers in comparison to speckle contrast.
The microstructure of non-polar a-plane (112¯0) InGaN quantum wells
Authors: Griffiths James T. , Oehler Fabrice , Tang Fengzai , Zhang Siyuan , Fu Wai Yuen , Zhu Tongtong , Findlay Scott D. , Zheng Changlin , Etheridge Joanne , Martin Tomas L. , Bagot Paul A. J. , Moody Micheal P. , Sutherland Danny , Dawson Philip , Kappers Menno J. , Humphreys Colin J. , Oliver Rachel A.
Published: May 2016

Atom probe tomography and quantitative scanning transmission electron microscopy are used to assess the composition of non-polar a-plane (11-20) InGaN quantum wells for applications in optoelectronics. The average quantum well composition measured by atom probe tomography and quantitative scanning transmission electron microscopy quantitatively agrees with measurements by X-ray diffraction. Atom probe tomography is further applied to study the distribution of indium atoms in non-polar a-plane (11-20) InGaN quantum wells. An inhomogeneous indium distribution is observed by frequency distribution analysis of the atom probe tomography measurements. The optical properties of non-polar (11-20) InGaN quantum wells with indium compositions varying from 7.9% to 20.6% are studied. In contrast to non-polar m-plane (1-100) InGaN quantum wells, the non-polar a-plane (11-20) InGaN quantum wells emit at longer emission wavelengths at the equivalent indium composition. The non-polar a-plane (11-20) quantum wells also show broader spectral linewidths. The longer emission wavelengths and broader spectral linewidths may be related to the observed inhomogeneous indium distribution.
A compressible two-phase model for dispersed particle flows with application from dense to dilute regimes
Authors: McGrath Thomas P. , St. Clair Jeffrey G. , Balachandar S.
Published: May 2016

Multiphase flows are present in many important fields ranging from multiphase explosions to chemical processing. An important subset of multiphase flow applications involves dispersed materials, such as particles, droplets, and bubbles. This work presents an Eulerian–Eulerian model for multiphase flows containing dispersed particles surrounded by a continuous media such as air or water. Following a large body of multiphase literature, the driving force for particle acceleration is modeled as a direct function of both the continuous-phase pressure gradient and the gradient of intergranular stress existing within the particle phase. While the application of these two components of driving force is well accepted in much of the literature, other models exist in which the particle-phase pressure gradient itself drives particle motion. The multiphase model treats all phases as compressible and is derived to ensure adherence to the 2nd Law of Thermodynamics. The governing equations are presented and discussed, and a characteristic analysis shows the model to be hyperbolic, with a degeneracy in the case that the intergranular stress, which is modeled as a configuration pressure, is zero. Finally, results from a two sample problems involving shock-induced particle dispersion are presented. The results agree well with experimental measurements, providing initial confidence in the proposed model.
Analytic energy gradients for the coupled-cluster singles and doubles method with the density-fitting approximation
Authors: Bozkaya Uğur , Sherrill C. David
Published: May 2016

An efficient implementation is presented for analytic gradients of the coupled-cluster singles and doubles (CCSD) method with the density-fitting approximation, denoted DF-CCSD. Frozen core terms are also included. When applied to a set of alkanes, the DF-CCSD analytic gradients are significantly accelerated compared to conventional CCSD for larger molecules. The efficiency of our DF-CCSD algorithm arises from the acceleration of several different terms, which are designated as the “gradient terms”: computation of particle density matrices (PDMs), generalized Fock-matrix (GFM), solution of the Z-vector equation, formation of the relaxed PDMs and GFM, back-transformation of PDMs and GFM to the atomic orbital (AO) basis, and evaluation of gradients in the AO basis. For the largest member of the alkane set (C10H22), the computational times for the gradient terms (with the cc-pVTZ basis set) are 2582.6 (CCSD) and 310.7 (DF-CCSD) min, respectively, a speed up of more than 8-folds. For gradient related terms, the DF approach avoids the usage of four-index electron repulsion integrals. Based on our previous study [U. Bozkaya, J. Chem. Phys. 141, 124108 (2014)], our formalism completely avoids construction or storage of the 4-index two-particle density matrix (TPDM), using instead 2- and 3-index TPDMs. The DF approach introduces negligible errors for equilibrium bond lengths and harmonic vibrational frequencies.
Short range atomic migration in amorphous silicon
Authors: Strauß F. , Jerliu B. , Geue T. , Stahn J. , Schmidt H.
Published: May 2016

Experiments on self-diffusion in amorphous silicon between 400 and 500 °C are presented, which were carried out by neutron reflectometry in combination with 29Si/natSi isotope multilayers. Short range diffusion is detected on a length scale of about 2 nm, while long range diffusion is absent. Diffusivities are in the order of 10−19–10−20 m2/s and decrease with increasing annealing time, reaching an undetectable low value for long annealing times. This behavior is strongly correlated to structural relaxation and can be explained as a result of point defect annihilation. Diffusivities for short annealing times of 60 s follow the Arrhenius law with an activation enthalpy of (0.74 ± 0.21) eV, which is interpreted as the activation enthalpy of Si migration.