bluuebunny/crossref_metadata_2025 huggingface dataset:
Changes in fetal cardiac axis between 8 and 15 weeks' gestation
Authors: McBrien A. , Howley L. , Yamamoto Y. , Hutchinson D. , Hirose A. , Sekar P. , Jain V. , Motan T. , Trines J. , Savard W. , Hornberger L. K.
Published: April 2013

Objectives

To document changes in the normal embryonic/fetal cardiac axis in the late first and early second trimesters of pregnancy.

Methods

Images from 188 fetal echocardiograms performed prospectively between 8 and 15 weeks' gestation in 166 healthy pregnancies and in 10 pregnancies with severe fetal heart disease were reviewed. For each echocardiogram, three measurements of the cardiac axis were taken in the axial plane at the level of the four‐chamber view. Differences in mean embryonic/fetal cardiac axis at different gestational ages in the healthy pregnancies were compared.

Results

The mean ± SD embryonic/fetal cardiac axis was 25.5 ± 11.5° from 8 + 0 to 9 + 6 weeks (Group  1), 40.4 ± 9.2° from 10 + 0 to 11 + 6 weeks (Group  2), 49.2 ± 7.4° from 12 + 0 to 12 + 6 weeks (Group  3), 50.6 ± 5.7° from 13 + 0 to 13 + 6 weeks (Group 4) and 48.6 ± 7.3° from 14 + 0 to 14 + 6 weeks (Group 5). Groups 1 and 2 were significantly different from each other and all other groups (P < 0.05). The results for 22 cases with repeat measurements from 8 + 0 to 11 + 6 and 12 + 0 to 14 + 6 weeks confirmed that the embryonic/fetal cardiac axis increased significantly (P < 0.001). In the cases with severe congenital heart disease, the cardiac axis was > 90th centile in four cases and < 10th centile in two cases.

Conclusions

The embryonic cardiac axis is relatively midline at 8 weeks and levorotates in the late first trimester. By 12 weeks' gestation, the normal leftward fetal cardiac axis is established and remains stable until at least 14 + 6 weeks. Observation of an abnormal cardiac axis in some cases of severe congenital heart disease prior to 15 weeks' gestation may assist in prenatal detection. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd.
Methods for generating families of univariate continuous distributions in the recent decades
Authors: Lee Carl , Famoye Felix , Alzaatreh Ayman Y.
Published: April 2013

There has been a renewed interest in developing more flexible statistical distributions in recent decades. A major milestone in the methods for generating statistical distributions is undoubtedly the system of differential equation approach. There is a recent renewed interest in generating skewed distributions. Generally speaking, the methods developed prior to 1980s may be summarized into three categories: (1) method of differential equation, (2) method of transformation, and (3) quantile method. Techniques developed since 1980s may be categorized as ‘methods of combination’ for the reason that these methods attempt to combine existing distributions into new distributions or adding new parameters to an existing distribution. This article discusses five general methods of combination and their variations. These five are (1) method of generating skew distributions, (2) method of adding parameters (e.g., exponentiation), (3) beta generated method, (4) transformed‐transformer method, and (5) composite method.WIREs Comput Stat2013, 5:219–238. doi: 10.1002/wics.1255

This article is categorized under:

Algorithms and Computational Methods > Random Number Generation

Statistical and Graphical Methods of Data Analysis > Modeling Methods and Algorithms

Statistical and Graphical Methods of Data Analysis > Nonparametric Methods
Comparison of the Frying Performance of High Oleic Oils Subjected to Discontinuous and Prolonged Thermal Treatment
Authors: Romano Raffaele , Manzo Nadia , Le Grottaglie Laura , Giordano Anella , Romano Annalisa , Masi Paolo
Published: April 2013

Frying is a popular practice because of its unique sensory characteristics and low cost. The high temperature reached with this cooking method alters molecules present in the oil. The deterioration of the oil depends primarily on its chemical composition. The aim of this study was to evaluate the thermal stability of high oleic sunflower oil (HOSO), sunflower oil (SO) and mixed oil (MIX) during deep frying of French fries. Octanoic acid and unsaturated fatty acid (UFA)/saturated fatty acid (SFA) ratio showed a good correlation with total polar compounds (TPC) for all frying samples analyzed. HOSO and MIX were characterized by reduced levels of thermal degradation, while SO resulted in the highest values of oxidation products (highest TPC values). SO was also the oil more retained by the food matrix, whereas MIX was the least absorbed. HOSO and MIX, having a high oleic acid content (77.58 and 59.92 %, respectively) and a low linoleic acid content (13.42 and 25.70 %, respectively), showed the best characteristics for the frying process.
Disaster Preparedness and Pandemic Plans: A Survey of Nebraska Home Health Agencies
Authors: Kassmeier Michele D. , Medcalf Sharon , Hansen Keith , Smith Philip W.
Published: April 2013

Objective

To develop a tool that assesses disaster-planning strategies used by Home Health Agencies (HHAs) throughout Nebraska.

Methods

A survey of HHAs in Nebraska was created, distributed, and analyzed to assess and gain information about their written disaster plans. Part 1 of this 2-part survey identified agencies with written disaster plans and collected basic information about plan and structure. Part 2 identified detailed characteristics of the HHA and their pandemic influenza plans. Also, pandemic influenza preparedness of HHAs was assessed and compared to other health care institutions.

Results

More than 90% of the HHAs that responded to the survey reported that they have written disaster plans; almost half of the plans address strategies for surge capacity. The majority of HHAs with plans also have disaster-specific plans for pandemic influenza preparedness. Our findings suggest that Nebraska HHAs have taken substantial steps toward preparedness, although individual plans may vary considerably.

Conclusions

This survey provides a first step at evaluating HHA disaster preparedness plans. It also demonstrates that Nebraska HHAs have taken substantial steps toward being prepared, although individual plans vary widely. (Disaster Med Public Health Preparedness. 2013;0:1–9)
A Resource Management Tool for Public Health Continuity of Operations During Disasters
Authors: Turner Anne M. , Reeder Blaine , Wallace James C.
Published: April 2013

Objective

We developed and validated a user-centered information system to support the local planning of public health continuity of operations for the Community Health Services Division, Public Health - Seattle & King County, Washington.

Methods

The Continuity of Operations Data Analysis (CODA) system was designed as a prototype developed using requirements identified through participatory design. CODA uses open-source software that links personnel contact and licensing information with needed skills and clinic locations for 821 employees at 14 public health clinics in Seattle and King County. Using a web-based interface, CODA can visualize locations of personnel in relationship to clinics to assist clinic managers in allocating public health personnel and resources under dynamic conditions.

Results

Based on user input, the CODA prototype was designed as a low-cost, user-friendly system to inventory and manage public health resources. In emergency conditions, the system can run on a stand-alone battery-powered laptop computer. A formative evaluation by managers of multiple public health centers confirmed the prototype design's usefulness. Emergency management administrators also provided positive feedback about the system during a separate demonstration.

Conclusions

Validation of the CODA information design prototype by public health managers and emergency management administrators demonstrates the potential usefulness of building a resource management system using open-source technologies and participatory design principles.(Disaster Med Public Health Preparedness. 2013;0:1–7)
Plasma 25-hydroxyvitamin D3, folate and vitamin B12 biomarkers among international colorectal cancer patients: a pilot study
Authors: Ulrich Cornelia M. , Toriola Adetunji T. , Siegel Erin M. , Brenner Hermann , Chang-Claude Jenny , Abbenhardt Clare , Kotzmann Jana , Song Xiaoling , Owen Robert W. , Hoffmeister Michael , Becher Heiko , Shibata David , Vickers Kathy , Rush Shannon K. , Makar Karen , Würtele Gerd , Haubner Roswitha , Sellers Thomas A. , Grady William
Published: April 2013

Vitamin D and folate are associated with decreased colorectal cancer risk and their association with colorectal cancer prognosis is under investigation. We assessed the levels of plasma 25-hydroxyvitamin D3 (25(OH)D3), folate and vitamin B12 in an international pilot study in order to determine variability of these biomarkers based on geographical location. Plasma 25(OH)D3, folate and vitamin B12 concentrations were measured in 149 invasive, newly diagnosed colorectal cancer cases from Heidelberg (Germany), Seattle (WA, USA), and Tampa (FL, USA) and in ninety-one age- and sex-matched controls. Their associations with potential predictors were assessed using multivariate linear regression analyses. Plasma 25(OH)D3, folate and vitamin B12 concentrations differed by location. Other predictors were season for 25(OH)D3 and tumour stage (vitamin B12). Season-corrected average 25(OH)D3 concentrations were higher in Heidelberg (31·7 ng/ml; range 11·0–83·0 ng/ml) than in Seattle (23·3 ng/ml; range 4·0–80·0 ng/ml) and Tampa (21·1 ng/ml; range 4·6–51·6 ng/ml). In Heidelberg, a strong seasonal variation was observed. Folate (11·1 ng/ml) and vitamin B12 (395 pg/ml) concentrations in Heidelberg were lower than those in Seattle (25·3 ng/ml and 740 pg/ml, respectively) and Tampa (23·8 ng/ml and 522 pg/ml, respectively). Differences in plasma 25(OH)D3 and folate concentrations between Heidelberg and the US sites were observed, probably reflecting variation in outdoor activities and sun-avoidance behaviour during summer as well as in folic acid fortification and supplement use. Intra-site differences at each study location were greater than between-location variability, suggesting that individual health behaviours play a significant role. Nevertheless, the intra-site differences we observed may be due to chance because of the limited sample size. Our pilot study illustrates the value of an international cohort in studying colorectal cancer prognosis to discern geographical differences in a broad range of exposures.
Industrial research at the Eastern Telegraph Company, 1872–1929
Authors: NOAKES RICHARD
Published: April 2013

By the late nineteenth century the submarine telegraph cable industry, which had blossomed in the 1850s, had reached what historians regard as technological maturity. For a host of commercial, cultural and technical reasons, the industry seems to have become conservative in its attitude towards technological development, which is reflected in the small scale of its staff and facilities for research and development. This paper argues that the attitude of the cable industry towards research and development was less conservative and altogether more complex than historians have suggested. Focusing on the crucial case of the Eastern Telegraph Company, the largest single operator of submarine cables, it shows how the company encouraged inventive activity among outside and in-house electricians and, in 1903, established a small research laboratory where staff and outside scientific advisers pursued new methods of cable signalling and cable designs. The scale of research and development at the Eastern Telegraph Company, however, was small by comparison with that of its nearest competitor, Western Union, and dwarfed by that of large electrical manufacturers. This paper explores the reasons for this comparatively weak provision but also suggests that this was not inappropriate for a service-sector firm.
Listening for the Lex Orandi: The Constructed Theology of Contemporary Worship Events
Authors: Holmes Stephen R.
Published: April 2013

Scholarly attention to the popular style of contemporary worship has so far been infrequent, and generally dismissive. Dismissive attitudes have generally been based on claims that individual contemporary worship songs are lacking in theological development, and that contemporary worship merely apes the mores of pop culture, replacing a proper liturgical event with something akin to a rock concert. In this paper I suggest that both these criticisms are false. The first is a misunderstanding of the nature of the liturgical tradition of contemporary worship, in which the crucial liturgical event is the ‘time of worship’, constructed out of a number of songs and other liturgical elements, which together construct a liturgical narrative with theological and pastoral depth; criticising individual songs is therefore largely irrelevant. The second fails to pay attention to the nuanced negotiation with popular culture that is evident in the tradition of contemporary worship, when observed carefully; dominant cultural practices are not unreflectively adopted, but modified and, if embraced, embraced critically and put to use. I demonstrate these two points by offering readings of two (video recordings of) contemporary worship events, Matt Redman's Facedown DVD and Tim Hughes's Happy Day DVD; in each case I explore the ways in which cultural practices are modified and effectively subverted in pursuit of a liturgical goal, and offer a theological reading of the narrative of the time of worship. I propose that, whilst there are significant differences, both can be seen to be liturgically responsible and theologically deep experiences of worship.
Thinking about Roman Imperialism: Postcolonialism, Globalisation and Beyond?
Authors: Gardner Andrew
Published: April 2013

For the last twenty years or so, archaeologists of Roman Britain, among other provinces, have been seeking ways of moving beyond the concept of ‘Romanisation’ as a framework for thinking about Roman imperialism. Many of the ideas proposed have been drawn from two related bodies of thought which have emerged as ways of understanding the contemporary world: postcolonialism and globalisation theory. While achieving significant success in transforming interpretations of the Roman world, applications of these approaches present some fresh problems of theoretical and practical coherence. These in turn point to important issues to do with the role of theory in Roman archaeology, issues which have rarely been tackled head-on but which present obstacles to interdisciplinary dialogue. The aim of this paper is to evaluate and compare the perspectives of postcolonial and globalisation theories, assess their strengths and weaknesses, and suggest some possibilities for linking the insights of these and other approaches to define a more holistic agenda for Roman archaeology.
The Church–Clergy Relationship and Anti-discrimination Law
Authors: Hatzis Nicholas
Published: April 2013

In its recent judgment in Hosanna-Tabor Evangelical Lutheran Church and School v EEOC, the United States Supreme Court held that the First Amendment precludes the application of anti-discrimination law to the employment relationship between a church and its clergy. In 2005 the House of Lords had reached the opposite conclusion, ruling, in Percy v Board of National Mission of the Church of Scotland, that the decision to dismiss an ordained minister was not a spiritual matter falling outside the scope of anti-discrimination legislation. This article argues that Percy largely neglected important aspects of church autonomy and that the reasoning in Hosanna-Tabor offers an opportunity to rethink whether secular law should be allowed to affect a religious group's decision to appoint or dismiss a minister.
How Novel Was Vatican II?
Authors: Tanner Norman
Published: April 2013

The Second Vatican Council is recognised by the Roman Catholic Church as the twenty-first ecumenical council. The largest in terms of participants and one of the longest-running, it also covered the widest range of topics and produced the largest volume of documents and decrees. This article, based on the text of the ninth Lyndwood Lecture, examines a number of characteristics of Vatican II in comparison with previous councils, arguing that, while in many ways Vatican II was novel, in its composition, agenda, influence and reception one can discern parallels with past councils back as far as the first ecumenical council at Nicea in 325.1
The internationalization of musical life at the end of the nineteenth century in modernized Paris and Rome
Authors: ZUR NIEDEN GESA
Published: April 2013

This article examines the relationship between the processes of urban renovation in European capitals and the internationalization of musical theatre productions, using the example of theatres constructed in Paris and Rome at the end of the nineteenth century. Due to the limited availability of governmental and municipal funding, the more popular theatres in both capitals came to provide an important space for musical productions on an avant-garde level, with international repertoires and casts.
Pandering to Ignorance on Climate Change: Lessons from an Investment Strategist
Authors: Burkle Frederick M.
Published: April 2013

An investment strategist recently published, in the journal Nature, an impassioned plea to all scientists that they must begin to speak out on the resource crisis exacerbated by global warming. In this Editorial response, the author reminds health professionals that they can no longer stay silent and pander to the ignorance of others, and challenges them, along with multidisciplinary partners and stakeholders, to define a strong collaborative and cooperative stance on climate change.

Burkle FM Jr. Pandering to ignorance on climate change: lessons from an investment strategist. Prehosp Disaster Med. 2013;28(4):1-2.
Fisheries subsidies and potential catch loss in SIDS Exclusive Economic Zones: food security implications
Authors: Sumaila U. Rashid , Dyck Andrew , Cheung William W.L.
Published: April 2013

We study the effects of providing subsidies to the fisheries in small island developing states (SIDS), where fisheries are important to both the food security and livelihoods of the populations. By analyzing data on current and potential catch and computing the potential catch losses from the Exclusive Economic Zones (EEZs) of SIDS, we find that, collectively, SIDS have currently overfished their waters to the extent that their current catch is just under 50 per cent of the maximum catch potential. This catch loss results in direct and indirect food security impacts in terms of losses in healthy, varied and nutrient-rich food, revenues, incomes and economic impacts in SIDS. Our results also demonstrate that capacity-enhancing subsidies contribute to overfishing while the effect of good subsidies is unclear and needs further analysis.
Charcoal production and household welfare in Uganda: a quantile regression approach
Authors: Ainembabazi John Herbert , Shively Gerald , Angelsen Arild
Published: April 2013

Previous research suggests that forest-dependent households tend to be poorer than other groups, and that extreme reliance on forest resources might constitute a poverty trap. We provide an example in which a non-timber forest product – charcoal – appears to be providing a pathway out of poverty for some rural households in Uganda. Data come from households living adjacent to natural forests, some of whom engage in charcoal production. We use a semi-parametric method to identify the determinants of participation in charcoal production and a quantile regression decomposition to measure the heterogeneous effect of participation on household income. We find that younger households and those with few productive assets are more likely to engage in charcoal production. We also show that, as a result of their participation, charcoal producers are better off than non-charcoal producers in terms of income, even though they are worse off in terms of productive assets.
Specifications for Hard Condensed Matter Specimens for Three-Dimensional High-Resolution Tomographies
Authors: Bleuet P. , Audoit G. , Barnes J.-P. , Bertheau J. , Dabin Y. , Dansas H. , Fabbri J.-M. , Florin B. , Gergaud P. , Grenier A. , Haberfehlner G. , Lay E. , Laurencin J. , Serra R. , Villanova J.
Published: April 2013

Tomography is a standard and invaluable technique that covers a large range of length scales. It gives access to the inner morphology of specimens and to the three-dimensional (3D) distribution of physical quantities such as elemental composition, crystalline phases, oxidation state, or strain. These data are necessary to determine the effective properties of investigated heterogeneous media. However, each tomographic technique relies on severe sampling conditions and physical principles that require the sample to be adequately shaped. For that purpose, a wide range of sample preparation techniques is used, including mechanical machining, polishing, sawing, ion milling, or chemical techniques. Here, we focus on the basics of tomography that justify such advanced sample preparation, before reviewing and illustrating the main techniques. Performances and limits are highlighted, and we identify the best preparation technique for a particular tomographic scale and application. The targeted tomography techniques include hard X-ray micro- and nanotomography, electron nanotomography, and atom probe tomography. The article mainly focuses on hard condensed matter, including porous materials, alloys, and microelectronics applications, but also includes, to a lesser extent, biological considerations.
Yet Another Nail in the Coffin of Zeroing: United States – Anti-Dumping Administrative Reviews and Other Measures Related to Imports of Certain Orange Juice from Brazil
Authors: SAGGI KAMAL , WU MARK
Published: April 2013

This paper analyzes Brazil's WTO challenge to the methods undertaken by the United States in calculating anti-dumping duties in administrative reviews and other investigations of Brazilian orange juice. The dispute resulted in a Panel ruling that conforms with earlier Appellate Body decisions outlawing the use of ‘weighted average to transaction’ zeroing in such reviews. However, we note that the Panel's stance was driven largely from a desire to preserve ‘stability and predictability’ within the system, suggesting a practical recognition of the shadow of past Appellate Body decisions on the same legal question. In addition, we argue that to understand fully the effects of zeroing, it is important to account for the underlying reasons behind observed price changes in the market. We show that zeroing is more likely to convert a negative dumping determination into a positive one when price changes are driven by variations in demand relative to when they are driven by variations in the cost of exporting. In the present case, Brazilian exporters of orange juice experienced an increase in (residual) demand for their product since, by reducing the local supply of round oranges, adverse weather conditions in the United States made it difficult for US orange-juice producers to meet local demand.
Kardiale Stamm- und Progenitorzelltherapie: Bereit für die Zukunft?
Authors: Emmert Maximilian Y. , Templin Christian
Published: April 2013

Herz-Kreislauf-Erkrankungen stellen die Haupttodesursache in den Industrienationen dar. Die regenerative Medizin verspricht erstmals einen neuartigen Therapieansatz für die Behandlung des akuten Myokardinfarktes und der chronischen ischämischen Kardiomyopathie, mit dem Ziel untergegangenes Myokardgewebe zu regenerieren oder zu ersetzen. In den letzten Jahren wurden zahlreiche experimentelle und klinische Studien mit unterschiedlichen Stamm- und Progenitorzellen durchgeführt. Metanalysen zeigten eine kardiale Funktionsverbesserung im Vergleich zu Kontroll-behandelten Patienten von ca. 3 %. Insgesamt konnten jedoch die zum Teil sehr positiven Befunde tierexperimenteller Arbeiten nicht in dem Ausmass bestätigt werden. Zahlreiche ungeklärte Fragen (Zelltyp, Applikationswege, Zellmenge, Zellformate, Zeitpunkt, Endpunkte) scheinen in diesem Zusammenhang für die limitierte Translation verantwortlich zu sein. Geeignete präklinische Grosstiermodelle und moderne nicht-invasive Bildgebungsverfahren, nicht nur zur Beurteilung der kardialen Funktion, sondern auch zur Langzeitdetektion transplantierter Zellen, spielen für zukünftige translationale Fragestellungen eine zentrale Rolle. Zukünftige Studien müssen ebenfalls zeigen, ob durch die Optimierung der adulten Stammzelltherapie und dem parakrinen Wirkmechanismus der Zellen ein langfristiger positiver Nutzen erzielt werden kann, oder ob neue pluripotente Stammzellen, wie die induzierten pluripotenten Stammzellen sich zu einer nebenwirkungsfreien Therapieoption entwickeln können. Aktuelle experimentelle Studien haben eine direkte Reprogrammierung von Fibroblasten in Kardiomyozyten gezeigt. Somit könnte in Zukunft auch eine regenerative Therapie ohne den direkten Einsatz von Stammzellen möglich werden.
Gas-to-cluster effects in S 2p-excited SF6
Authors: Flesch Roman , Serdaroglu Ertugrul , Brykalova Xenia O. , Kan Elena I. , Klyushina Ekaterina S. , Krivosenko Yuri S. , Pavlychev Andrey A. , Rühl Eckart
Published: April 2013

High resolution X-ray spectroscopic studies on free SF6 molecules and SF6 clusters near the S 2p ionization thresholds are reported. Spectral changes occurring in clusters for the intense molecular-like S 2p1/2,3/2 → 6a1g-, 2t2g-, and 4eg-resonances are examined in detail. Neither gas-to-cluster spectral shifts nor changes in peak shape are observed for the pre-edge 6a1g-band. Significant changes in band shape and distinct gas-to-cluster shifts occur in the S 2p1/2,3/2 → 2t2g- and 4eg-transitions. These are found in the S 2p-ionization continua. The quasiatomic approach is used to assign the experimental results. It is shown that a convolution of asymmetric and symmetric contributions from Lorentzian and Gaussian line shapes allows us to model the spectral distribution of oscillator strength for the S 2p1/2,3/2 → 2t2g-, and 4eg-transitions. The asymmetry is due to trapping of the photoelectron within the finite size potential barrier. The Lorentzian contribution is found to be dominating in the line shape of the S 2p → 2t2g- and 4eg-bands. The spectroscopic parameters of the spin-orbit components of both the 2t2g- and 4eg-bands are extracted and their gas-to-cluster changes are analyzed. The photoelectron trapping times in free and clustered SF6 molecules are determined. Specifically, it is shown that spectral changes in clusters reflected in core-to-valence-transitions are due to a superposition of the singly scattered photoelectron waves at the neighboring molecules with the primary and multiply scattered waves within the molecular cage.
Density of atoms in Ar*(3p54s) states and gas temperatures in an argon surfatron plasma measured by tunable laser spectroscopy
Authors: Hübner S. , Sadeghi N. , Carbone E. A. D. , van der Mullen J. J. A. M.
Published: April 2013

This study presents the absolute argon 1 s (in Paschens’s notation) densities and the gas temperature, Tg, obtained in a surfatron plasma in the pressure range 0.65
10 mbar, for which the pressure broadening can no more be neglected. Tg is in the range of 480-750 K, increasing with pressure and decreasing with the distance from the microwave launcher. Taking into account the line of sight effects of the absorption measurements, a good agreement is found with our previous measurements by Rayleigh scattering of Tg at the tube center. In the studied pressure range, the Ar(4 s) atom densities are in the order of 1016−1018 m−3, increasing towards the end of the plasma column, decreasing with the pressure. In the low pressure side, a broad minimum is found around 10<p<20 mbar and hence the Ar(4 s) atom densities increase slightly with rising pressure. For the studied pressure range and all axial positions, the density ratio: 1s5/1s4/1s3 is very close to a Boltzmann equilibrium by electron impact mixing at the local Te, which was previously measured by Thomson scattering. The Ar(4 s) densities are successfully compared to a detailed Collisional Radiative Model.
Effect of a finite external heat transfer coefficient on the Darcy-Bénard instability in a vertical porous cylinder
Authors: Barletta A. , Storesletten L.
Published: April 2013

The onset of thermal convection in a vertical porous cylinder is studied by considering the heating from below and the cooling from above as caused by external forced convection processes. These processes are parametrised through a finite Biot number, and hence through third-kind, or Robin, temperature conditions imposed on the lower and upper boundaries of the cylinder. Both the horizontal plane boundaries and the cylindrical sidewall are assumed to be impermeable; the sidewall is modelled as a thermally insulated boundary. The linear stability analysis is carried out by studying separable normal modes, and the principle of exchange of stabilities is proved. It is shown that the Biot number does not affect the ordering of the instability modes that, when the radius-to-height aspect ratio increases, are displayed in sequence at the onset of convection. On the other hand, the Biot number plays a central role in determining the transition aspect ratios from one mode to its follower. In the limit of a vanishingly small Biot number, just the first (non-axisymmetric) mode is displayed at the onset of convection, for every value of the aspect ratio.
An influence of mechanical deformations on crystal structure and spin configuration in magnetic nanowires
Authors: Ognev A. V. , Samardak A. S. , Chebotkevich L. A. , Sukovatitsina E. V. , Stebliy M. E. , Modin E. B. , Pustovalov E. V. , Plotnikov V. S. , Nasirpouri F.
Published: April 2013

The influence of strain induced into individual fine-grain Ni nanowires on crystalline and magnetic structures is discussed in this paper. Using transmission electron microscopy, we have found that the crystal twinning occurs in the strained parts of the nanowires. Changes in crystalline structure due to the mechanical deformations induce a magnetic anisotropy, which leads to a transverse magnetic structure.
Preisach analysis of sputtered SmCo thick films
Authors: SoltanMohammad Sina , Belochapkine Serguei , Missell F. P. , Rhen F. M. F.
Published: April 2013

Here, we present an implementation of the moving Preisach model to describe the magnetic behaviour of Sm-Co films. We use two independent Preisach distributions to separate the magnetization into reversible and irreversible components. The numerical simulation works very well for a system where two magnetic phases are weakly or negligibility coupled. We tested our implementation on nanocrystalline Sm-Co films prepared by sputtering and having composition around Sm25Co75. We found that the Sm25Co75 film has a soft and hard phase and quantified their contributions to the total magnetization. Using the moving Preisach model, we characterized the properties of the hard phase, which has a coercivity of 1.26 T and contribution of 74% to the total magnetization. The soft magnetic phase contributes 26% to the total magnetization and has a coercivity of 0.056 T.
Magnetic Compton scattering studies of magneto-dielectric Ba(Co0.85Mn0.15)O3−δ
Authors: Shinoda R. , Itou M. , Sakurai Y. , Yamamoto H. , Hirao N. , Baba Y. , Iwase A. , Matsui T.
Published: April 2013

We revealed that the Ba(Co0.85Mn0.15)O3−δ ceramic samples exhibited ferromagnetic-dielectric behavior below the magnetic transition temperature of about 35 K. The origin of their magnetic ordering was expected to super-exchange coupling of Co4+(d5)-O2−-Mn4+(d3) with bonding angle of 180° and/or Mn4+(d3)-O2−-Mn4+(d3) with bonding angle of 90°. The magnetic spin momentum estimated by the magnetic Compton profiles (MCP) of the samples had similar temperature dependence as that determined by the temperature dependence of magnetic moment by superconducting quantum interference device, which meant that the observed magnetic moments could be ascribed to the spin moment. The shapes of the MCPs of the samples were completely same regardless of the temperature measured. This result indicates that there are no changes of the momentum space distribution of spin density between ferromagnetic and paramagnetic states. So, this magnetic transition is simply caused by a thermal fluctuation of the spin.
Crossover between in-plane and perpendicular anisotropy in Ta/CoxFe100-x/MgO films as a function of Co composition
Authors: Ahn Sung-Min , Beach G. S. D.
Published: April 2013

Interfacial magnetic anisotropy in Ta/CoxFe100-x (CoFe)/MgO films for alloy compositions spanning pure Co to pure Fe has been studied in order to investigate the role of chemical composition in the onset of perpendicular magnetic anisotropy at the CoFe/MgO interface. Out-of-plane magnetization is not observed in Ta/Fe/MgO (x = 0) and Ta/Co/MgO (x = 100), for all ranges of CoFe thickness (t), but a t-dependent crossover between in-plane and out-of-plane anisotropy is found for x = 20, 50, and 80. Interestingly, effective magnetic anisotropy Ku as well as interfacial anisotropy Ki are maximized for Co50Fe50 at a fixed t = 0.8 nm. The results suggest that the degree of filling of valence bands in the CoFe adjacent to the interface, which determines the relative population of the anisotropic d-bands, plays an important role in the interfacial anisotropy brought on by CoFe-O hybridization at the metal/oxide interface.
Band structure, magnetic, and transport properties of two dimensional compounds Sr2−xGdxCoO4
Authors: Yao Q. W. , Wang X. L. , Kimura H. , Dou S. X. , Konstantinov K. , Cheng Z. X. , Hong F. , Zhao H. Y. , Qiu H. , Ozawa K.
Published: April 2013

The layered perovskite compound Sr2−xGdxCoO4 has not yet been subjected to detailed study so far. In this report, structures, transport, magnetic properties, and first principle calculations will be reported for the two dimensional compounds Sr2−xGdxCoO4 (x = 0.5, 0.75, 1, 1.25). Rietveld refinement revealed that these compounds are crystallized in K2NiF4-type structures with space group I4/mmm. It was found that the lattice parameter c decreases as x increases. Through the Curies Weiss fitting of the temperature dependent magnetization, it was found that the Sr1.25Gd0.75CoO4 sample exhibits a weak ferromagnetic to paramagnetic transition at about 62 K, with a Curie constant of 0.113 emu K/mol. Band structure calculations indicated that electrons of these compounds are spin polarized at the Fermi level. The 2-D Variable Range Hopping model fitting indicated that the two dimensional variable range hopping mechanism could be used to account for the conducting mechanism for these samples.
Nanophase stability in a granular FeRh-Cu system
Authors: Barua Radhika , Jimenez-Villacorta Felix , Shield J. E. , Heiman D. , Lewis L. H.
Published: April 2013

A granular system of FeRh-based nanoprecipitates (∼10–15 nm diameter) embedded in a rapidly solidified copper ribbon matrix was found to transit from a metastable tetragonal L10 (AuCu-1-type) structure to a stable B2 (CsCl-type) structure upon annealing-induced coarsening to ∼94 nm. The hysteretic magnetic transition observed at ∼100 K develops a gradual broadening that accompanies the L10 → B2 crystal structure transition. It is proposed that the Cu matrix influences the structural and magnetic properties of the FeRh-based nanoparticles through interfacial strain and chemical effects. These results emphasize the sensitivity of the magnetostructural response of FeRh to changes in the nanostructural scale, and provide pathways for tailoring the transition.
Enhanced magnetic performance of metal-organic nanowire arrays by FeCo/polypyrrole co-electrodeposition
Authors: Luo X. J. , Xia W. B. , Gao J. L. , Zhang S. Y. , Li Y. L. , Tang S. L. , Du Y. W.
Published: April 2013

FeCo/polypyrrole (PPy) composite nanowire array, which shows enhanced magnetic remanence and coercivity along the nanowires, was fabricated by AC electrodeposition using anodic aluminum oxide templates. High resolution transmission electron microscopy shows that PPy grows on the surface of FeCo nanowires forming a coaxial nanowire structure, with a coating layer of about 4 nm. It suggests that the decreased dipolar interaction due to the reduced nanowire diameters is responsible for the enhancement of magnetic performance. The possible mechanism of this coating may be that PPy is inclined to nucleate along the pore wall of the templates.
Optimisation of NbN thin films on GaAs substrates for in-situ single photon detection in structured photonic devices
Authors: Reithmaier G. , Senf J. , Lichtmannecker S. , Reichert T. , Flassig F. , Voss A. , Gross R. , Finley J. J.
Published: April 2013

We prepare NbN thin films by DC magnetron sputtering on [100] GaAs substrates, optimise their quality, and demonstrate their use for efficient single photon detection in the near-infrared. The interrelation between the Nb:N content, growth temperature, and crystal quality is established for 4–22 nm thick films. Optimised films exhibit a superconducting critical temperature of 12.6 ± 0.2K for a film thickness of 22 ± 0.5 nm and 10.2 ± 0.2 K for 4 ± 0.5 nm thick films that are suitable for single photon detection. The optimum growth temperature is shown to be ∼475 °C reflecting a trade-off between enhanced surface diffusion, which improves the crystal quality, and arsenic evaporation from the GaAs substrate. Analysis of the elemental composition of the films provides strong evidence that the δ-phase of NbN is formed in optimised samples, controlled primarily via the nitrogen partial pressure during growth. By patterning optimum 4 nm and 22 nm thick films into a 100 nm wide, 369μm long nanowire meander using electron beam lithography and reactive ion etching, we fabricated single photon detectors on GaAs substrates. Time-resolved studies of the photo-response, absolute detection efficiency, and dark count rates of these detectors as a function of the bias current reveal maximum single photon detection efficiencies as high as 21 ± 2% at 4.3 ± 0.1 K with ∼50 k dark counts per second for bias currents of 98%IC at a wavelength of 950 nm. As expected, similar detectors fabricated from 22 nm thick films exhibit much lower efficiencies (0.004%) with very low dark count rates ≤3 cps. The maximum lateral extension of a photo-generated resistive region is estimated to be 30 ± 8 nm, clearly identifying the low detection efficiency and dark count rate of the thick film detectors as arising from hotspot cooling via the heat reservoir provided by the NbN film.
Defect reduction in photon-accelerated negative bias instability of InGaZnO thin-film transistors by high-pressure water vapor annealing
Authors: Seung Rim You , Jeong Wooho , Du Ahn Byung , Jae Kim Hyun
Published: April 2013

We investigated the effects of high-pressure water vapor annealing (WHPA) under negative bias temperature illumination stress and light incidence on amorphous InGaZnO thin-film transistors. WHPA could improve device reliability and reduce the hump occurrence. It was attributed to the effective reduction and passivation in oxygen vacancies under WHPA. By comparing the experimental and technology computer-aided design simulation, we could confirm that the low-density of deep-donor-like oxygen vacancy (Vo) states near the valance band maximum contributed to the reduction of photo-excited single ionized oxygen vacancies (Vo+) and double ionized oxygen vacancies (Vo2+) as shallow-donor states near the conduction band minimum.
Hybrid pyroelectric/nanotube LiNbO3/TiO2 X-ray source
Authors: Alivov Yahya , Klopfer Michael , Molloi Sabee
Published: April 2013

LiNbO3/TiO2 pyroelectric/nanotube system was fabricated by bonding electrochemically grown TiO2 nanotubes on −z face of pyroelectric LiNbO3 crystal and X-ray emission properties of such system were studied. The hybrid LiNbO3/TiO2 system had both higher electron energy and output X-ray flux compared to LiNbO3 without nanotubes. The endpoint energy increased from 38–45 keV to 55–74 keV, and the maximum X-ray flux increased by a factor of 3.6. The improved output energy and flux are thought to be due to the electric field amplification of nanotube tips increasing the efficiency of ionization of residual gas.
Surface field excitation by an obliquely incident wave
Authors: Konoplev I. V. , Phipps A. R. , Phelps A. D. R. , Robertson C. W. , Ronald K. , Cross A. W.
Published: April 2013

Observation of surface field excitation by an obliquely incident wave inside a cylindrical two-dimensional periodic surface lattice is a step forward toward THz Cherenkov amplifiers. Here we observe and discuss this phenomenon, investigating it using different approaches. The results are compared, and it is shown that an increase in the lattice contrast results in excitation of surface fields by an obliquely incident wave resulting in the eigenmode formation. Measurements were conducted by studying forward transmission of the signal, and it is shown that the measured gaps in the spectra are associated with the eigenmode formation rather than band gap establishment.
Controllable-permittivity and high-tunability of Ba0.5Sr0.5TiO3/MgO based ceramics by composite configuration
Authors: Tang Linjiang , Wang Jinwen , Zhai Jiwei , Bing Kong Ling , Yao Xi
Published: April 2013

Ba0.5Sr0.5TiO3 (BST50)/MgO composites, with 2-2-type configurations, consisting of BST layers and MgO layers, were fabricated by using tape-casting and laminating technique. Microstructure, dielectric response, and tunable properties of the 2-2-type composites were investigated. An important feature of the 2-2 type composites is that DC fields can be effectively applied to the high-permittivity ferroelectric phase when the fields are applied in parallel direction to the inter-phase boundaries. As a result, with increasing volume fraction (q) of MgO, tunability of the composites remained almost unchanged, whereas their permittivity value could be reduced significantly. This behavior has not been observed in the conventional 3-0 type composites.
Generation of phonons from electrostriction in small-core optical waveguides
Authors: Laude Vincent , Beugnot Jean-Charles
Published: April 2013

We investigate the generation of acoustic phonons from electrostriction of optical waves in small core waveguides. We specifically consider simple step-index strip waveguides composed of silica or silicon in air, with sub-micron lateral dimensions. Such waveguidessupport one or a few optical modes, but a rich spectrum of acoustic phonons that becomes densely populated as the phonon frequency increases. We evaluate rigorously the phonon energy density that results from the electrostriction of two frequency detuned guided optical waves,that are either co- or contra-propagating, including phonon loss. Plotting this energy density as a function of frequency detuning reveals the phononwave packets that are electrostrictively active and gives a quantitative estimation of the energy transfer from optical waves to particular phonons. Furthermore, in the backward interaction geometry, the dispersion relation of such phonons can be accessed directly by varying the optical wavelength.
Role of defect states in magnetic and electrical properties of ZnO nanowires
Authors: Kushwaha Ajay , Tyagi Himanshu , Aslam M.
Published: April 2013

The perfect crystalline nature along with a defect ridden surface controls the electrical and magnetic properties of ZnOnanowires. Herein, a soft chemical approach is presented to grow ZnOnanowires in powder as well as highly oriented nanowirefilm form. Photoluminescencemeasurements reveal high surface defects in as-grown nanowire and post growth annealing treatment in argon and oxygen atmosphere reduces intensity of defect emissions. Magnetic measurements illustrate the ferromagnetic nature of submicron sized zinc oxide (ZnO) nanorods arising due to singly charged oxygen vacancies.Nanowires show diamagnetic behavior when annealed at higher temperature in oxygen while argon annealing does not affect the magnetic behavior. In an analogous manner, we also investigated the effect of surface defects on electrical properties and correlated electrical conductivity with a responsible defect state.
Circuit-level input integration in bacterial gene regulation
Authors: Espinar Lorena , Dies Marta , Çağatay Tolga , Süel Gürol M. , Garcia-Ojalvo Jordi
Published: April 2013

Gene regulatory circuits can receive multiple simultaneous inputs, which can enter the system through different locations. It is thus necessary to establish how these genetic circuits integrate multiple inputs as a function of their relative entry points. Here, we use the dynamic circuit regulating competence for DNA uptake in
Bacillus subtilis
as a model system to investigate this issue. Specifically, we map the response of single cells in vivo to a combination of (
i
) a chemical signal controlling the constitutive expression of key competence genes, and (
ii
) a genetic perturbation in the form of copy number variation of one of these genes, which mimics the level of stress signals sensed by the bacteria. Quantitative time-lapse fluorescence microscopy shows that a variety of dynamical behaviors can be reached by the combination of the two inputs. Additionally, the integration depends strongly on the relative locations where the two perturbations enter the circuit. Specifically, when the two inputs act upon different circuit elements, their integration generates novel dynamical behavior, whereas inputs affecting the same element do not. An in silico bidimensional bifurcation analysis of a mathematical model of the circuit offers good quantitative agreement with the experimental observations, and sheds light on the dynamical mechanisms leading to the different integrated responses exhibited by the gene regulatory circuit.
Parametric representation of open quantum systems and cross-over from quantum to classical environment
Authors: Calvani Dario , Cuccoli Alessandro , Gidopoulos Nikitas I. , Verrucchi Paola
Published: April 2013

The behavior of most physical systems is affected by their natural surroundings. A quantum system with an environment is referred to as open, and its study varies according to the classical or quantum description adopted for the environment. We propose an approach to open quantum systems that allows us to follow the cross-over from quantum to classical environments; to achieve this, we devise an exact parametric representation of the principal system, based on generalized coherent states for the environment. The method is applied to the

Heisenberg star with frustration, where the quantum character of the environment varies with the couplings entering the Hamiltonian
H
. We find that when the star is in an eigenstate of
H
, the central spin behaves as if it were in an effective magnetic field, pointing in the direction set by the environmental coherent-state angle variables

, and broadened according to their quantum probability distribution. Such distribution is independent of
φ
, whereas as a function of
θ
is seen to get narrower as the quantum character of the environment is reduced, collapsing into a Dirac-δ function in the classical limit. In such limit, because
φ
is left undetermined, the Von Neumann entropy of the central spin remains finite; in fact, it is equal to the entanglement of the original fully quantum model, a result that establishes a relation between this latter quantity and the Berry phase characterizing the dynamics of the central spin in the effective magnetic field.