bluuebunny/crossref_metadata_2025 huggingface dataset:
DIMETER: A Haptic Master Device for Tremor Diagnosis in Neurodegenerative Diseases
Authors: González Roberto , Barrientos Antonio , Del Cerro Jaime , Coca Benito
Published: March 2014

In this study, a device based on patient motion capture is developed for the reliable and non-invasive diagnosis of neurodegenerative diseases. The primary objective of this study is the classification of differential diagnosis between Parkinson's disease (PD) and essential tremor (ET). The DIMETER system has been used in the diagnoses of a significant number of patients at two medical centers in Spain. Research studies on classification have primarily focused on the use of well-known and reliable diagnosis criteria developed by qualified personnel. Here, we first present a literature review of the methods used to detect and evaluate tremor; then, we describe the DIMETER device in terms of the software and hardware used and the battery of tests developed to obtain the best diagnoses. All of the tests are classified and described in terms of the characteristics of the data obtained. A list of parameters obtained from the tests is provided, and the results obtained using multilayer perceptron (MLP) neural networks are presented and analyzed.
Synthetic Spectrum Approach for Brillouin Optical Time-Domain Reflectometry
Authors: Nishiguchi Ken'ichi , Li Che-Hsien , Guzik Artur , Kishida Kinzo
Published: March 2014

We propose a novel method to improve the spatial resolution of Brillouin optical time-domain reflectometry (BOTDR), referred to as synthetic BOTDR (S-BOTDR), and experimentally verify the resolution improvements. Due to the uncertainty relation between position and frequency, the spatial resolution of a conventional BOTDR system has been limited to about one meter. In S-BOTDR, a synthetic spectrum is obtained by combining four Brillouin spectrums measured with different composite pump lights and different composite low-pass filters. We mathematically show that the resolution limit, in principle, for conventional BOTDR can be surpassed by S-BOTDR and experimentally prove that S-BOTDR attained a 10-cm spatial resolution. To the best of our knowledge, this has never been achieved or reported.
Positron Emission Tomography/Computed Tomography in the Staging of Colon Cancer
Authors: Lee Jae Hyung , Lee Min Ro
Published: March 2014

Purpose: Accurate preoperative staging of colon cancer is essential for providing the optimal treatment strategy and evaluating the expected prognosis. The aim of this study is to assess the value of positron emission tomography/computed tomography (PET/CT) over conventional studies in the staging of colon cancer.Methods: A total of 266 colon cancer patients diagnosed between January 2008 and December 2010 were assessed with both PET/CT and conventional studies. Discordance with PET/CT and conventional studies were evaluated, and changes in the management strategy were assessed for each stage. Discordant findings were verified by using intraoperative examination, pathology reports, and follow-up imaging studies.Results: Multidetector computed tomography (MDCT) and PET/CT showed similar accuracy in detecting lymph node metastasis in patients with clinical stage III (36.2% vs. 42%, P = 0.822) and stage IV (60.3% vs. 63.5%, P = 0.509) disease. PET/CT led to a change in management strategy for 1 of 40 patients (2.5%) with clinical stage I, 0 of 25 patients (0%) with stage II, 9 of 138 patients (6.5%) with stage III, and 8 of 63 patients (12.7%) with stage IV disease.Conclusion: PET/CT changed the management plan in 6.5% of patients with clinical stage III and 12.7% of patients with clinical stage IV colon cancer. Our findings suggest that PET/CT may be considered as a routine staging tool for clinical stage III and IV colon cancers.
Un savon « sans frontières » : une nouvelle carrière pour le savon de Naplouse ?
Authors: Bontemps Véronique
Published: March 2014

Conjuguant approche historique et anthropologique, cet article se penche sur le devenir du savon de Naplouse, longtemps fleuron de l’activité économique de la ville, ainsi que sur ses formes actuelles de patrimonialisation et de relance à travers le portrait d’un petit savonnier atypique, Mustapha Tbeîla. Le parcours de ce petit entrepreneur conduit à interroger les rapports entre tradition, patrimoine et modernité dans le contexte de l’occupation par Israël des Territoires palestiniens. Il permet aussi d’envisager les manières parfois inattendues dont les Palestiniens peuvent se réapproprier, voire travestir les politiques israéliennes de contrôle frontalier et de séparation.
Définition et sélection de l'expert IT : Approches cognitives et sociales
Authors: Guittard Claude , Welter Adeline
Published: March 2014

L’objet de ce travail est d’analyser le mode de sélection des experts en technologie de l’information (IT), domaine où la formalisation de ce processus de sélection n’est pas encore établie. Cela s’explique notamment par la multitude de définitions et de missions désignant l’expert et l’expertise. En effet, en s’intéressant aux définitions les plus couramment appliquées de l’expert, des discordances entre les domaines d’expertise sont mises en évidence. Ceci crée chez certains des barrières à la promotion de la profession et démobilise les éventuels candidats. Partant de ce constat, ce travail développe un exemple récent : le cas du projet européen IT2Rhine. Par le biais d’une approche ethnographique, cette étude de cas permet de présenter un mode de sélection des experts dans un cadre particulièrement intéressant, puisque les initiateurs du projet ne sont pas issus des mêmes secteurs (universitaire, industriel...) et n’ont donc pas les mêmes exigences de recrutement. Cependant, conduits par leur objectif commun, ils sont parvenus à la construction d’une matrice reprenant les caractéristiques principales, que chacun d’eux jugeaient indispensables à un expert en IT.
Gestion des connaissances et dynamiques collaboratives dans les pôles de compétitivité
Authors: Barbier Jean-Yves , Boissonnet Catherine
Published: March 2014

A partir d’une série de cas abordés au sein de l’Observatoire des Pôles de Compétitivité et en recherche-intervention, nous proposons un cadre d’analyse de l’impact de la gestion des connaissances sur les dynamiques collaboratives des pôles de compétitivité. Nous identifions trois schémas d’organisation des échanges que nous relions aux modalités d’externalisation et de partage des savoirs tacites, considérés comme des vecteurs essentiels de l’innovation.
De la connaissance des réseaux aux réseaux de la connaissance. Vers de nouveaux modèles d'organisation innovants
Authors: Blum Guillaume , Ebrahimi Mehran
Published: March 2014

Cet article présente une conception réticulaire de la production de connaissance. Son objectif est de construire un idéal type de « réseau de connaissances » selon une posture épistémologique appropriée à la société de réseau actuelle. En effet, si la posture moderne pose un certain nombre de questions quant à sa validité pour décrire le monde contemporain de l’organisation, tout n’est pas à renier dans la modernité, comme la place du savoir scientifique qui demeure importante et ne correspond pas à n’importe quel discours. Mais la représentation moderne ne prend pas en considération que celui-ci s’intègre dans un réseau de connaissances où d’autres savoirs prennent leur place, et où interviennent des individus interagissant dans des milieux naturels et sociaux. Cela engendre, dans le monde des organisations, de nouvelles façons de s’organiser et un nouveau mode d’émergence de savoir en réseaux.
D'une « démocratie créatrice » à un « capitalisme raisonnable »
Authors: Bazzoli Laure , Dutraive Véronique
Published: March 2014

J. Dewey et J.R. Commons ont partagé un même combat intellectuel et pratique pour la démocratie. L’article défend l’idée selon laquelle la proximité de leurs analyses va au-delà de l’hommage explicite de Commons à la philosophie sociale de Dewey pour fonder sa conception des sciences sociales. Sur la base d’une lecture croisée de ces auteurs, nous montrons la convergence de leurs visions de la démocratie comme idéal éthique et de l’État démocratique comme processus inachevé ainsi que la complémentarité des solutions proposées aux problèmes de la démocratie, en soulignant que Commons a fait une contribution notable à la conception pragmatiste en étendant la « démocratie créatrice » de Dewey à un « capitalisme raisonnable ».
Autorisation à l'échange sur des externalités
Authors: Bertrand Élodie
Published: March 2014

La négociation sur des externalités, supposée par le « théorème de Coase », rencontre un possible obstacle dans une interdiction morale ou sociale à échanger sur ce type de droit de propriété. Cet article montre que les tests empiriques du « théorème de Coase » mettent en lumière trois degrés sur l’échelle croissante de l’autorisation morale ou sociale à l’échange légal sur des externalités : 1) interdiction entre les voisins agriculteurs d’Ellickson [1986], 2) permission entre les apiculteurs et pomiculteurs étudiés par Cheung [1973] et 3) incitation morale dans les expérimentations de laboratoire de Hoffman et Spitzer [1982]. Ce travail contribue ainsi à l’analyse de l’interaction entre normes sociales et contrats d’échange, en se concentrant sur les normes qui autorisent ou non le contrat.
On the Description of Individual Course Units for Programme Assessment and Better Syllabuses
Authors: Barros Joao Paulo
Published: March 2014

Presently, higher education programmes are being assessed at several different levels, locally, or even countrywide. In this paper, we propose a template for the description of each curricular unit in higher education programmes that seeks to promote reflective teaching, widely acknowledged as fundamental to improve practices leading to improved student learning, while being advantageous and convenient for programme assessment by external entities. To this end, we take as a starting point the template that all Portuguese higher education institutions have to fill for each curricular unit, for programme assessment purposes. Based on the literature, we argue this new template format fosters teacher reflection and provides additional and easier to compare data for accreditation boards, and the whole education community, most notably, students. Finally, we argue that it can and should be used to improve syllabuses.
Activity Theory Approach to Developing Context-Aware Mobile Learning Systems for Understanding Scientific Phenomenon and Theories
Authors: Uden Lorna , Hwang Gwo-Jen
Published: March 2014

Mobile computing offers potential opportunities for students’ learning especially when it combines a sensing device such as RFID (Radio Frequency Identification). Researchers have indicated that a key feature of in-field learning supported by mobile devices and technology is context awareness, with which context and functionality provided by the learning system are adapted to the user’s situation. However, the design of context-aware mobile learning systems provides the authors with major challenges in terms of both defining use context as well as developing appropriate concepts relevant to the design of contextual information on the systems. Educators have highlighted the role of activity in science development and learning, implying that activity theory can be used to design a mobile learning environment. This paper presents the use of activity theory as a framework for describing the design of a context aware mobile learning application. A case study for the design of a mobile learning application for science learning is described using activity theory.
Measuring the Characteristics of Hypervisor I/O Scheduling in the Cloud for Virtual Machine Performance Interference
Authors: Yang Ziye , Fang Haifeng , Wu Yingjun , Li Chunqi
Published: March 2014

In virtualized environments, the customers who purchase virtual machines (VMs) from a third-party cloud would expect that their VMs run in an isolated manner. However, the performance of a VM can be negatively affected by co-resident VMs. In this paper, the authors propose vExplorer, a distributed VM I/O performance measurement and analysis framework, where one can use a set of representative I/O operations to identify the I/O scheduling characteristics within a hypervisor, and potentially leverage this knowledge to carry out I/O based performance attacks to slow down the execution of the target VMs. The authors evaluate their prototype on both Xen and VMware platforms with four server benchmarks and show that vExplorer is practical and effective. The authors also conduct similar tests on Amazon’s EC2 platform and successfully slow down the performance of target VMs.
’n Prakties-teologiese besinning oor die begeleiding en toerusting van kinders tot dienswerk as ’n weg tot die navolging van die gesindheid van Christus
Authors: Breed Gert , Kruger Ferdi P.
Published: March 2014

A practical-theological reflection on coaching and equipping children for service as a way to emulating the attitude of Christ. The hypothesis for this research is that the youth is an inherent part of the church. The church, which includes the children, received spiritual gifts from God. The edification of the church is the main purpose in the utilisation of all the gifts. The church received a significant responsibility in equipping and convoying children to be obedient in their calling to be followers of Jesus Christ. Parents and children must use their gifts for their own diakonia. The word diakonia gives expression to the fact that diakonia must take place in accordance to the calling by God. In recent research the expression diakonia also received a more comprehensive meaning. The research field will be explored in four phases and, in doing so, try to come to grips with the current practical-theological situation. In phase one the authors tried to offer a descriptive reflection on research in the practical theology. In phase two the authors undertook exploratory research from the field of the social psychology in order to indicate the prominent role of wrong attitudes and insufficient convoying of children in the praxis. Therefore the authors undertook an intra-disciplinary conversation with the development psychology. In phase three the authors offered basic-theoretical perspectives from Scripture in order to show how the praxis must be. In the last phase of this research practical-theoretical perspectives are explored in order to underline the responsibility of churches in this regard of equipping children in fulfilling their own diakonia. The authors drew a conclusion from their research that children who serve in diakonia and also in obedience to Christ, are also people that are enabled to show the attitude of Jesus Christ towards the world. Parents and other believers must serve in mentoring children. By mentoring children in their diakonia, they enable children and also contribute towards spiritual maturity in their lives.
Acoustic Prosodic Parameters in Japanese and Slovene: Accent and Intonation
Authors: GOLOB Nina
Published: March 2014

The study investigates realizations of the three acoustic parameters, duration, fundamental frequency and intensity, in relation to accent and intonation in Japanese and Slovene. Ten native speakers of each language pronounced nonsense words of different accentual patterns placed within the declarative-interrogative intonational context. Results of the acoustic analysis reveal clear differences in behavior of the three parameters under various conditions, and suggest the following phonological differences between the two languages: 1. Prosodic features realizing accent and intonation differ, 2. Interaction between accent and intonation differs, and 3. Prosodic features function uniformly within different units of successive segments, the so-called prosodic units. However, looking into the overall characteristics of the acoustic signal, certain similarities are also observed. The study anticipates that the above phonological differences, especially those realized as phonetic similarities represent a great difficulty in acquisition of L2 prosody, and specific examples of a possible L1 interference are provided.
Laparoscopic Treatment of Splenic Injury in Blunt Abdominal Trauma
Authors: Yahya Ali I , Shwerief Hussen E , Latifi Rifat , Endaha Najala E , Algyead Fatma O
Published: March 2014

Introduction

Road traffic accidents are very common and pose a serious community problem in Libya. In 1998, the surgery unit at Zliten Teaching Hospital began using laparoscopy in the trauma unit for patients who were admitted to intensive care unit. A challenge for trauma surgeons is negative laparotomy which can result in increased complications for patients.

Objective

We reviewed medical records following the implementation of laparoscopic techniques in the trauma unit to determine the effectiveness of the treatment with patients who had been in road traffic accidents.

Methods

Review of medical records for patients admitted to Zliten General Hospital in Libya who had been involved in road traffic accidents was conducted. The records analyzed were from 1998 through 2012.

Results

One hundred and twenty-four patients underwent diagnostic and therapeutic laparoscopy over the 14 years time period, of which 76 patients had blunt abdominal trauma. The review of Zliten's trauma registry shows that 18 patients had splenic trauma and those patients who had splenic trauma.

Out of the 18 patients who had blunt splenic trauma, three patients underwent laparoscopic splenectomy because it was not possible to preserve the spleen. One patient, aged 9 years, had an open laparotomy because the surgeons found that the spleen has avulsed completely and was lying at the left iliac fossa during diagnostic laparoscopy. Fourteen patients had small lacerations in the spleen. The spleen was not removed in these patients because profuse bleeding did not occur. No significant morbidity and no mortality were recorded. The hospital stay was between 2 and 5 days.

Conclusion

By using laparoscopy in trauma, we were able to preserve the spleen in the majority of our patients with splenic injuries who were hemodinamically stable.

How to cite this article

Yahya AI, Shwerief HE, Latifi R, Endaha NE, Algyead FO. Laparoscopic Treatment of Splenic Injury in Blunt Abdominal Trauma. J Trauma Critical Care Emerg Surg 2013;2(3):112-115.
Opinion Paper: Forest management and biodiversity
Authors: Schulze E. D. , Bouriaud L. , Bussler H. , Gossner M. , Walentowski H. , Hessenmöller D. , Bouriaud O. , Gadow K. v.
Published: March 2014

Abstract. In this opinion paper we investigate the effects of forest management on animal and plant biodiversity by comparing protected areas with intensively and extensively managed forests in Germany and in Romania. We want to know the extent to which differences in diversity of Romanian compared to German forests are based on management. The number of tree species was not different in protected and managed forests ranging between 1.8 and 2.6 species per plot in Germany and 1.3 and 4.0 in Romania. Also herbaceous species were independent of management, ranging between 13 species per plot in protected forests of Romania and 38 species per plot in German coniferous forest. Coarse woody debris was generally low, also in protected forests (14 to 39 m3 ha−1). The main difference between Romania and Germany was the volume of standing dead trees (9 to 28 m3 ha−1 for Romania), which resulted in larger numbers of forest relict saproxylic beetles independent of management. Large predators (wolves, bears and lynxes) are only found in regions with low human intervention. Thus, we identified a "cut and leave" type of management in Romania, in which clear-felling of forest are followed by long periods of no human intervention. Forests managed in the "cut and leave" mode contained the highest diversity, due to a natural succession of plant species and due to habitat continuity for animals. In Germany intensive management eliminates poorly formed tree individual and species of low market value during stand development. Forest protection does not ensure the maintenance of more light demanding key species of earlier stages of succession unless competition by shade-tolerant competitors is reduced through disturbances. We compare the economics of intensive and extensive management. The "cut and leave" mode delivers less wood to the wood market, but saves expenses of tending, thinning and administration. Thus the net income could be quite similar to intensive management at a higher level of biodiversity. Our analysis suggests that forest protection per se does not yet ensure the maintenance of species. Clear-felling followed by natural succession may even be superior to the protection of old growth forests, regarding biodiversity. Further research is needed to substantiate this hypothesis.
La reforma de la formación inicial del profesorado de ciencias de secundaria: propuesta de un diseño del currículo basado en competencias
Authors: Perales Palacios Francisco Javier , Cabo Hernández José Manuel , Vilchez González Jose Miguel , Fernández González Manuel , González García Francisco , Jiménez Tejada Pilar
Published: March 2014

El principal objetivo de este trabajo es proponer un mecanismo de selección de competencias específicas para la formación inicial del profesorado de ciencias experimentales, contando para ello con distintas fuentes relevantes para dicha formación. Con tal fin hemos hecho uso de un procedimiento consistente en ir incorporando de forma crítica las competencias procedentes de las siguientes fuentes curriculares: los modelos de formación inicial del profesorado vigentes en la literatura educativa, el currículo actual de ciencias en la educación secundaria obligatoria en España, el Programa internacional de evaluación PISA, la opinión del profesorado en activo mediante una encuesta cuyos resultados más relevantes son mostrados, las concepciones epistemológicas del profesorado, la profesionalización docente y las demandas que genera y, finalmente, la dimensión social de la ciencia.
Incidencia del «aplicacionismo» en la integración de la modelización matemática en la enseñanza universitaria de las ciencias experimentales
Authors: Barquero Farràs Berta , Bosch Casabò Marianna , Gascón Pérez Josep
Published: March 2014

Investigaciones recientes sobre la enseñanza y aprendizaje de la modelización matemática subrayan la existencia de fuertes restricciones institucionales que afectan su integración generalizada y a largo plazo en nuestros sistemas educativos. El estudio de estas restricciones y la forma cómo las nuevas propuestas educativas intentan superarlas aparece como un paso inevitable para la investigación en educación matemática. Desde el marco de la Teoría antropológica de lo didáctico, se propone una jerarquía de niveles de codeterminación didáctica como herramienta para detectar y analizar la emergencia de estas restricciones, y con el objetivo de saber en qué nivel es necesario actuar para instaurar las condiciones que se requieren para que la modelización pueda existir como una actividad normalizada. Vamos a centrarnos en el caso de la enseñanza universitaria de las matemáticas para las Ciencias Experimentales, poniendo especial atención en aquellas restricciones que proviene de la «epistemología dominante».
Nanostructure modification to carbon nanowall surface employing hydrogen peroxide solution
Authors: Shimoeda Hironao , Kondo Hiroki , Ishikawa Kenji , Hiramatsu Mineo , Sekine Makoto , Hori Masaru
Published: March 2014

Carbon nanowalls (CNWs), which are three-dimensional carbon nanomaterials consisting of stacks of graphene sheets vertically standing on substrates, possess a mazelike architecture containing high-density graphene edges and large-area plane surfaces. A selective morphological modification technique for the surfaces of CNWs after their growth has been developed employing hydrogen peroxide (H2O2) solution. It was found that oxidative radicals in H2O2 solution formed characteristic nanometer-scale asperities on the CNW surface without etching from the top edges. Photoelectron spectra indicate that hydroxyl adsorption and subsequent reactions at the edge and plane of graphene contribute to the selective morphological change on the CNW surface.
Origins of vertical phase separation in P3HT:PCBM mixed films
Authors: Liu I-Hsiu , Chao Yi-Ping , Fang Jian-Jhih , Tseng Wei-Hsuan , Lan Yu-Bing , Chen Yu-Jen , Wu Kaung-Hsiung , Chen Mei-Hsin
Published: March 2014

The origins of vertical phase separation and their implication on the device efficiency of poly(3-hexylthiophene):[6,6]-phenyl C61-butyric acid methyl ester (P3HT:PCBM) based solar cells, with both regular and inverted structures, were investigated. We found that the light irradiation and the filtration processes during the device fabrications are two key steps that induce the vertical phase separation in the active layers. Upon light irradiation, the devices with inverted structures exhibit improved power conversion efficiency, whereas the regular devices show degradation. The inverted devices spun cast with filtered P3HT:PCBM solution also present a better improvement as compared to regular devices. X-ray and ultraviolet photoemission spectroscopies indicate that both illumination and filtration enhance the vertical phase separation of the blend film with additional PCBM segregated to the bottom interface.
Polarized light-emitting backlight unit using a retardation film for improving light efficiency in a twisted nematic mode liquid crystal module
Authors: Moon Jeongmin , Lee Sungrae , Lee Sejin , Jung Woohyun , Oh Kyunghwan
Published: March 2014

We propose and demonstrate a new polarized backlight unit (BLU) configuration to enhance light transmission in a twisted nematic (TN) mode liquid crystal (LC) panel. By adding an optimized phase retardation film (PRF) to the BLU, we efficiently controlled the polarization state of the light from the light guide plate (LGP), enabling it to be aligned along the transmission axis of the bottom polarizer of the LC panel. We designed and fabricated a 7 in. edge-lit BLU with a PRF. To obtain a uniform positional distribution in both light intensity and degree of polarization (DOP), the LGP was optimized with linear groove patterns. To maximize BLU light transmission through the bottom polarizer in a TN-mode LC panel, the slow axis of the PRF was aligned at 22.5° with respect to the LED array axis. We improved the transmittance from 45 to 72%.
Optical Study of High-Tc Superconducting Copper Oxides
Authors: Tajima S. , Uchida S. , Kanbe S. , Kitazawa K. , Fueki K. , Tanaka S.
Published: March 2014

The optical reflectivity spectra of the new high-Tc superconductors (La1-xAx)2CuO4 (A=Ba,Ca,Sr) and MBa2Cu3Oy (M=Y,Er) were investigated. In each spectrum a clear plasma edge was observed. However, the spectrum deviated obviouly from the Drude-type spectrum, indicating the existence of some excitation in the infrared region. The origin of this excitation and its relevance to the superconductivity were discussed.
Infrared Properties of the High Tc Superconductor (La, Y)–Ba–Cu–O and La–Sr–Cu–O Compounds
Authors: Saito Yosuke , Yoshizaki Ryozo , Sawada Hideaki , Iwazumi Toshiaki , Abe Yoshihito , Matsuura Etsuyuki
Published: March 2014

Infrared transmission spectra were measured in YBa2Cu3Oz prepared by rapid cooling from various temperatures. Two types of spectra have been obtained corresponding to the crystal structures, tetragonal or orthorhomblc. The spectrum of La0.4Ba0.6CuOw whose superconducting transition temperature of 50 K was similar to the spectra of tetragonal-YBa2Cu3Oz compounds and could be distinguished from the spectrum of (La0.925Ba0.075)2CuO4-y.
High-Tc Superconductivity in Ln–Ba–Cu–O Systems (Ln=Lanthanide Atoms)
Authors: Sato Masatoshi , Hosoya Syoichi , Shamoto Shin-ichi , Onoda Masashige
Published: March 2014

High-Tc superconductivity has been discovered for Ln-Ba-Cu-O systems with Ln=Lu, Yb, Tm, Er, Ho, Dy, Gd, Eu, Sm and Nd. The transition temperatures Tc are as high as that of the Y-Ba-Cu-O system, although almost all Ln atoms carry magnetic moments. The insensitivity of the Tc-values seems to be understood by the consideration of their structures, where the superconducting electrons are within the layers of Ba-Cu-O system sepeparated by the layers of Ln atoms.
The Superconducting Properties for La–Sr–Cu–O Systems
Authors: Wakata M. , Fujiwara F. , Kubo Y. , Miyashita S. , Matsuno S. , Nagai T. , Higuma H. , Yoshizaki K. , Morita M. , Yokoyama S. , Yamamoto S. , Yamada T.
Published: March 2014

Superconducting oxides, La–Sr–Cu–O and Y–Ba–Cu–O were prepared using nitrate mixture by spray dry method and/or oxide and carbonate powder mixtures followed by pressing and sintering. The superconducting properties such as critical temperature (Tc) and critical current density (Jc) were measured by resistive and inductive methods, and transport current and magnetization measurements, respectively. The Tc's(the resistive offset) were 32, 91 K for La and Y system, respectively. The Jc(77K) of 1,840 A/cm2 was observed for Y system by transport current measurement.
Superconductivity above 90 K in Single Phase Y–Ba–Cu–O Compound
Authors: Nagarajan V. , Paulose P. L. , Grover A. K. , Dhar S. K. , Sampathkumaran E. V.
Published: March 2014

The results of x-ray diffraction, electrical resistance, DC and AC magnetization studies on two specimens of compositions Y2.1Ba3.9Cu6O14 and Y1.8Ba4.2Cu6O14 are presented. Our studies confirm that La3Ba3Cu6O14 type ortnornombic phase is responsible for superconductivity in 90K range. The heat treatment that yields high quality samples with sharp transition in electrical resistance as well as in AC magnetic susceptibility measurements is described. Magnetic response just below Tc is found to be sensitive to the measuring field.
Correlation of Layered Structure and Superconductivity in (La, Y)–Ba–Cu–O System
Authors: Iwazumi Toshiaki , Yoshizaki Ryozo , Sawada Hideaki , Saito Yosuke , Ikeda Hiroshi , Abe Yoshihito , Matsuura Etsuyuki
Published: March 2014

The oxide superconductors In the (La,Y)–Ba–Cu–O system were Investigated by X-ray powder diffraction, electrical resistivity and magnetic susceptibility measurements. In the La–Ba–Cu–O system, we have synthesized the two types of the superconductors by varying only their composition ratio. In the Y–Ba–Cu–O system, the correlation between the onset temperature of the superconducting transition and the oxygen contents was found.
High Tc Superconductivity of BaxY1-xCuO3-y
Authors: Zhang Zhang , Qirui Qirui , Qian Qian , Yitai Yitai , Chen Chen , Zuyao Zuyao , Guan Guan , Weiyan Weiyan , Zhao Zhao , Yong Yong , Zhang Zhang , Han Han , Xia Xia , Jiansheng Jiansheng , Pan Pan , Guoqiang Guoqiang , Cao Cao , Liezhao Liezhao , Zhang Zhang , Minjian Minjian , Yu Yu , Daoqi Daoqi , He He , Zhenhui Zhenhui , Sun Sun , Shifang Shifang , Zhang Zhang , Tao Tao
Published: March 2014

High Tc superconductivity transition was observed in both single-phase and multi-phase samples in Ba–Y–Cu–O system. The differences between these two types of samples in electrical resistivity and a.c. magnetic susceptibility and in superconductivity were also noticed and have been discussed by us in this letter.
Fermi Surface Instability of Quasi-Two-Dimensional Tight Binding Electrons: A Possible Phase Diagram of (La1-xMx)2CuO4
Authors: Hasegawa Yasumasa , Fukuyama Hidetoshi
Published: March 2014

The instability of the nearly nested Fermi surface in quasi-two-dimensional systems against the spin density wave (SDW) is investigated as a function of band filling within the mean field approximation. It is found that SDW is stable only in a small region around the half-filled case. The present result implies that the ground state of (La1-xMx)2Cu4 for very small x will be the SDW state and the superconductivity state is stabilized above some critical value of x of the order of 0.01.
Electronic Properties of High Tc Superconducting Oxides
Authors: Uchida S. , Tajima S. , Takagi H. , Kishio K. , Hasegawa T. , Kitazawa K. , Fueki K. , Tanaka S.
Published: March 2014

The normal-state electronic properties of (La,A)2CuO4 and LnBa2Cu3O7-y are investigated to have an insight into the electronic states of these high Tc superconductors. The experimental results suggest that the states may be modified strongly due possibly to the Fermi surface instability and/or to some excitations extending to higher energies.
High-Pressure X-Ray Study on (L1-xAx)aCubOcSystem
Authors: Takahashi Hiroki , Murayama Chizuko , Yomo Shusuke , Mōri Nobuo , Ustumi Wataru , Yagi Takehiko
Published: March 2014

The (L1-xAx)aCubOc system have high Tc superconductivity, where L stands for La, Y and so on, A for the alkaline earth elements, like Ba, Sr and so on. The pressure effect on the lattice constants of YBa2Cu3O7-y has been measured at room temperature up to 60 kbar. Compression coefficients of a- and c-axis are found to be almost the same value of (3.3±0.3)×10-4 kbar-1, which is larger than the value for (La0.9Sr0.1)2CuO4 and the ratio of c/a is found to be almost constant, whose tendency was observed in (La0.9Sr0.1)2CuO4. But the ratio of a/b decreases slightly under pressure.
BW State of the Superfluid 3He in Restricted Geometry
Authors: Kara Jun'ichiro , Nagai Katsuhiko
Published: March 2014

The BW state of the superfluid 3He in a slab with specular reflection walls is investigated by the method of quasiclassical Green function. The separation of the slab is still much larger than the Fermi wave length, but not necessarily larger than the coherence length. The second order phase transition between the BW state and the Planar state due to the size effects is studied in detail. The phase diagram shows a reentrant behavior.
Ultrasonic Studies and the Phonon Modes of High Tc Superconductors BaPb1-xBixO3 and (La1-xSrx)2CuO4
Authors: Horie Yuuji , Fukami Takeshi , Mase Shoichi
Published: March 2014

The measurements of the temperature dependence of the sound attenuation coefficient α(T) were performed with the sintered oxide superconductors of BaPb1-xBixO3 (BPBO: Tc,max=12 K at x = 0.25) and (La1-xSrx)2CuO4 (LSCO: Tc,max=38 K at x = 0.07). In the curves of α(T) versus T several peaks were observed below room temperature: the peak points were T ∼ 30, 75 and 150 K for BPBO (x = 0.25) and T ∼ 100 and 200 K for LSCO (x = 0.07). Some of these peaks exhibit the existence of optical modes in the B. Z. center whose energy in the temperature scale is identified with the peak points. Using these experimental results we calculated the phonon dispersion curves and found a good similarity in the softening behaviors of optic phonons between BPBO and LSCO. On the basis of these results, we discussed about the origin of the high Tc in these materials.
Anisotropy of the Superconducting Critical Magnetic Field Hc2 of La–M–Cu–O System (M=Sr and Ba)
Authors: Shamoto S. , Onoda M. , Sato M. , Hosoya S.
Published: March 2014

Results of experimental studies on single crystals of high-Tc oxide superconductors are presented. The anisotropy of the superconducting critical magnetic field Hc2 of (La1-xMx)2CuO4-δ (M=Ba and Sr and x∼0.075) indicates that the ratio of the conductivities along the directions within and perpendicular to the c plane, σ||
/σ⊥, is of the order of 102. The results show the direct evidence of the two dimensional character of the electron transport. The thermoelectric power of the same crystal of (La1-xSrxCuO4-δ is also shown. Brief comments on the crystal preparation are presented.
Single Crystal Growth of Superconducting Oxides with the Layered Perovskite Structure
Authors: Kawabe Ushio , Hasegawa Haruhiro , Aita Toshiyuki , Ishiba Tsutomu
Published: March 2014

(La,Sr)2CuO4 single crystals were grown in a molten copper oxide flux at a relatively low temperature, and their habit planes were examined by X-ray Laue patterns.
Evidence for Electron-Electron Correlations in Pure and Sr-Doped La2CuO4
Authors: Maletta H. , Greene R. L. , Plaskett T. S. , Bednorz J. G. , Muller K. A.
Published: March 2014

SQUID susceptibility measurements on La2CuO4 and La2-xSrxCuO4 provide evidence for electron-electron correlations. Our data suggest that La2CuO4 has a spin-density wave (or antiferromagnetic) transition near 250 K. The Sr doped superconductors have a Pauli susceptibility in the normal state that is enhanced by electron-electron correlations. The variation in the superconducting Tc with Sr doping is not directly correlated with the change in electron density of states.
3He-A vs Quantum Electrodynamics: Paradox of Linear and Angular Momenta vs Chiral Anomaly
Authors: Volovik G. E.
Published: March 2014

Due to two nodes in the fermionic energy gap the normal fermionic quasiparticles take part in 3He-A dynamics even at T=0, producing a singular behavior of 3He-A at low temperatures. Near the nodes the fermionic quasiparticles interacting with the order parameter field are identical to massless right-handed electrons and left-handed positrons interacting with electromagnetic, weak and gravitational fields. As a result, the peculiarities in behavior of 3He-A (anomalous mass current, nonanalytic gradient expansion, nonconservation of the linear momentum of superflow at T=0, paradox of the orbital momentum, non-zero normal density at T=0, etc) are of the same origin as the chiral anomaly and vacuum polarization effects in quantum electrodynamics (QED).
On Spin Density and Charge Density Wave Instabilities of Tetragonal La2CuO4
Authors: Ozaki Masa-aki
Published: March 2014

We give the group theoretical classification of spin density wave (SDW) and charge density wave (CDW) (with lattice distortion) instabilities derived from half filled nesting. It is shown that on site (on oxygen), Cu–O and O–O nearest Coulomb interaction are favorable to unusual SDW on oxygen atom.
Percolative Superconductivity in Ba–La–Cu Oxide Prepared below 1000°C
Authors: Razavi F. S. , Koffyberg P. P. , Mitrović B.
Published: March 2014

Magnetic and resistivity measurements have been carried out on two samples of Ba0.15La1.85CuO4 that were heated below 1000°C. The superconductivity is found to be of nonbulk-percolative type in both of these samples.
The Nature of Superfluid 3He Confined in a Planar Geometry
Authors: Freeman M. R. , Germain R. S. , Opsahl L. , Houseman E. , Richardson R. C.
Published: March 2014

In order to improve our understanding of how superfluid 3He adapts itself to the presence of walls, we have begun experiments which use nuclear magnetic resonance to probe the order parameter while simultaneously measuring the superfluid density as liquid decouples from an oscillating substrate. Our present results are for ∼0.5 µm thick slabs, at pressures between 1.5 and 9 bar. The data are consistent with the assumption that A phase superfluid is stabilized in the slabs, although it is not possible to identify uniquely any particular phase. We also observe manifestations of the rapid exchange of atoms between the liquid and the highly polarized layer at the solid boundary.
Superfluid Helmholtz Resonance in Liquid 3He
Authors: Yamasaki S. , Takeda M. , Kodama T. , Shigi T. , Nagai K.
Published: March 2014

Using a glass filter as orifices, Helmholtz resonance signals have been observed in superfluid 3He in the temperature range of 0.2<T/Tc<0.9 and at six pressures between 0.61 and 28 bar. The experiments were carried out for two glass filters of 8.0and 4.2 µm pore diameter. For these pore sizes, only superfluid component can move through the orifices. From the measurements of the resonance frequencies for different pore length, the superfluid fraction ρs/ρ in the pore and the contribution due to the end correction have been obtained separately.
k-Dependent Energy Gap in Two Band Superconductors
Authors: Menezes O. L. T. De , Aligia A. A.
Published: March 2014

The presence of a k-dependent superconducting energy gap is studied. The quasi-particle electron-phonon interaction shows a strong variation of the effective coupling around the Fermi level within a two hybridized band model. Numerically results are obtained and connections with heavy fermion superconductor systems are discussed.
Superconductivity in Thin Films of UBe13
Authors: Kang J. H. , Maps J. , Goldman A. M. , Brooks J. S. , Fisk Z. , Smith James L.
Published: March 2014

Films of the heavy fermion compound UBe13 have been prepared by dc sputtering from a compound target. The transition temperatures of 3000 Å thick films deposited onto single-crystal sapphire substrates approach those of bulk material. Temperature dependences of the parallel and perpendicualar critical fileds of UBe13 were determined resistively. The ratio Hc11/Hc⊥ was found to be 1.25, a value which suggests the partial rather than complete of the films. This result implies that the pairing configuration in UBe13, at least near the surface, cannot be pure triplet, or any other pure state with L≠0.
Possible Phase Transition in UPt3 in a Magnetic Field?
Authors: Xu M-F. , Qian Y. J. , Schenstrom A. , Baum H-P. , Ketterson J. B. , Hinks D. , Levy M. , Sarma Bimal K.
Published: March 2014

Longitudinal sound attenuation was measured in a magnetic field in UPt3. A possible phase transition is indicated by the appearance of a small peak in the attenuation at about 0.6 Hc2. Below this peak, at low fields, the attenuation αs/αn varies linearly with the magnetic field H; close to Hc2, the attenuationhas a parabolic dependence αs/αn∼(Hc2-H)2. The peak, at the change over from linear to parabolic behavior may correspond to a phase transition in the vortex lattice.
Suppression of the Superfluid Transition of 3He in 350 nm Channels
Authors: Kotsubo V. , Hahn K. D. , Parpia J. M.
Published: March 2014

We have measured the suppresssion of the superfluid transition temperature due to confinement of the fluid by 350 nm diameter pores in Nuclepore filter. The experiments were carried out at several pressures between 0 bar and 29 bar, where the pressure variation allows us to vary the ratio of the coherence length to pore diameter by approximately a factor of five. The Nuclepore filter was mounted across an annular flow channel which formed part of the inertial bob of a torsional oscillator. Flow was induced by operating the device at its resonant frequency of 850 Hz at amplitudes between 50 pm and 10 nm. The measured suppression of the superfluid transition is less than that predicted by theory.
Thermoelectric Power Measurements on Some Chevrel Phase Superconductors
Authors: Sankaranarayanan V. , Balakrishnan Geetha , Srinivasan R. , Vaidhyanathan L. S.
Published: March 2014

The absolute thermoelectric power measurements on AgMo6S8, Mo6S8, pbMo6S8, SnMo6S8, SnMo6S8 were made from 4.2 to 300 k. All the compounds have positive thermoelectric power near room temperature. Mo6S8 and the compounds containing small metal ion such as Cu and Ag show a negative peak and the compounds containing large metal ion such as Pb, Sn show a positive peak in the thermopower vs. temperature graph. There seems to be a correlation between low temperature peak in the thermopower and delocalisation of the metal ion in the compound. Two mechanisms may account for the peaks in the thermopower viz. phonon drag effect and the enhancement of thermopower caused by the renormalisation of energy, velocity and relaxation time due to electron-phonon interaction. In the present case the mechanism mentioned later aoes not seem to provide an explanation for the negative peaks in the thermopower.
Voltage Oscillations in Percolating Superconducting Films
Authors: Gerber Alexander , Deutscher Guy
Published: March 2014

We have studied the superconducting transition in thin films of Pb and Al as a function of temperature and magnetic field. Examination of the films in a transmission electron microscope shows a percolative structure with typical small loop sizes of a few thousand angstroms in Pb and a few hundred in Al. We have observed an antisymmetric voltage across the samples as a function of an external DC magnetic field. This voltage shows sharp oscillations with a periodicity of about 250 gauss in Pb and about 1000 gauss in Al. These fields correspond to about one flux quantum in elementary loops of the respective films.
The Relation between Tc and Mössbauer Spectrum Parameters on Superconducting Sn Films
Authors: Taniwaki M. , Uneta M. , Maeda M.
Published: March 2014

Mössbauer spectra on vapor quenched Sn films were observed to investigate the lattice vibration and the electronic state in the disturbed lattice and to clarify their effects on the super-conducing- transition temperature, Tc, quantitatively. The average interatomic spacing in quenched Sn is expanded compared with β Sn, and this causes the lowering of Debye parameter and the increase in the number of free electrons. Tc estimated from these changes is 5.82 K which is in good accord with measured Tc.
Influence of Landau Interaction on the Paramagnetic Critical Behavior of S-Paired Superfluid Fermi Liquid
Authors: Jacak L. , Krzyźanowski I. H.
Published: March 2014

The s-paired system of strongly interacting fermions in the presence of magnetic field, of order of Tc, is considered in the framework of microscopic weak coupling approach. The paramagnetic instability phenomenon and unhomogeneous state, of Larkin-Ovchinnikov type, are studied for nonzeroth Landau interaction. They both turn to be very sensitive with respect to magnitude of spin exchange Landau interaction, which considerably modifies the paramagnetic phenomena of superfluid Fermi system. The temperature and field coordinates of tricritical points for superfluid-normal phase transition are determined with respect to zeroth spin exchange Landau parameter. Application to magnetically polarizable superconductor ErRh4B4 is suggested and bo parameter for this ternary compound is evaluated by use of Pauli limiting upper critical field model.
Pair-Breaking Mechanism for Disorder of Sb/Sn Thin Films
Authors: Kojima S. , Kobayashi T. , Okamoto K. , Ohtsuka M.
Published: March 2014

The superconducting transition temperature of Sb/Sn thin films was measured as a function of the normal sheet resistance. The samples were prepared by alternate deposition of Sb and Sn. When the thickness of Sn layer and the total layer number were kept constant, the normal sheet resistance
increased with the increase of Sb layer thickness. The normal sheet resistance of the samples ranged from 20 to 100(Ω). The transition temperature decreased proportionally with the increase of the normal sheet resistance. This result shows that there exists the pair-breaking mechanism dependent on the normal sheet resistance in the films. As the normal sheet resistance relates to the disorder in the films, it is suggested that the disorder contributes to the pair-breaking mechanism.
Paraconductivity and Magnetoresistance in Thin Films of In-Sn Oxide Superconductors
Authors: Mori Natsuki
Published: March 2014

The fluctuation conductivity above T
c (the paraconductivity) and the magnetoresistance were measured in superconducting thin films of indium-tin oxide. The paraconductivity data near T
c (∼3 K) are well described by the Aslamazov-Larkin and Maki-Thompson theories if the depairing parameter δ in the latter theory is suitably chosen. Results of the magnetoresistance were analyzed in terms of the Larkin formula to know the phase coherence time τφ of the conduction electrons. The relation between δ and τφ is discussed.
Anisotropic Superconductivity and NMR Relaxation Rate in Organic Superconductors
Authors: Hasegawa Yasumasa , Fukuyama Hidetoshi
Published: March 2014

Various possible types of anisotropic superconductivity are examined in both quasi-one and quasi-two dimensional systems. The NMR relaxation rate, T1
-1, is calculated for these states. Comparison with the recent experiment by Takigawa, Yasuoka and Saito on the quasi-one-dimensional organic superconductor, (TMTSF)2C104, indicates that the superconductivity of this family belongs to a novel type having lines of zeros of gaps on the Fermi surface. Onthe other hand the calculated T1
-1 for any possible types of quasi-two dimensional superconductors does not agree with that observed in (BEDT-TTF)2I3, which is quasi-two-dimensional organic conductor. A possibility of the origin of discrepancy between the theory and experiments is indicated.