bluuebunny/crossref_metadata_2025 huggingface dataset:
Bedeutung der Mathematik und Physik für die Erziehung
Authors: Kerst B.
Published: February 2013

Die Ausführungen von Studienrat Kerst sind aus dem gleichen Heft wie der vorstehende Aufsatz von Prof. Günther entnommen. Der Autor war zuletzt im Sachs. Volksbildungsministerium als Oberregierungsrat tätig. Er war ein alter Kämpfer der NSDAP und zugleich energischer Verfechter der Mathematik und Physik im höheren Schulwesen. Er erkannte, daß Wehrwille und Pflege des deutschen Kulturgutes die beiden wichtigen Gesichtspunkte sind, die die Förderung der deutschen Wissenschaft zur staatspolitischen Pflicht machen. Es sind die ganz ähnlichen Gedankengänge, wie sie dem Leser in dem Beitrag von Prof. Thomson (Phys. B1. 1. 51. 1944) entgegentraten.
Schulreform 1938 und Nachwuchs
Authors: Hamel Georg
Published: February 2013

Der Aufsatz ist ein Auszug aus dem Bericht: „Hochschule, höhere Schule und wissenschaftlicher Nachwuchs”︁, abgedruckt in den Mitteilungen der Gesellschaft deutscher Naturforscher und Ärzte, Dez. 1938. Er bringt Vorschläge darüber, wie den Auswirkungen der Verkürzung der Schulzeit auf der höheren Schule, wie sie die Neuordnung des höheren Schulwesens von 1938 bringt, begegnet werden muß, um trotzdem einen hochwertigen Nachwuchs für die wissenschaftlichen Gebiete zu sichern.
In vitro hemocompatibility and cytotoxicity study of poly(2‐methyl‐2‐oxazoline) for biomedical applications
Authors: Bauer Marius , Schroeder Susann , Tauhardt Lutz , Kempe Kristian , Schubert Ulrich S. , Fischer Dagmar
Published: February 2013

Since poly(2‐methyl‐2‐oxazolines) (PMeOx) attract high attention for the potential use in drug delivery, cytotoxicity, and hemocompatibility of a set of PMeOxs with molar masses in the range from 2 to 20 kDa are systematically investigated under standardized conditions in terms of molar mass, concentration and time dependency. PMeOx polymers are well tolerated in red blood cell aggregation and hemolysis assays without any damaging effects even at high concentrations up to 80 mg/mL. Only in long term cytotoxicity tests PMeOx polymers moderately influence cell viability in a time, concentration, and molar mass dependent manner. Referring to these results it can be concluded that PEtOx could be promising nonionic hydrophilic polymers for many biomedical applications without any cyto‐ and hemotoxic effects at typically used therapeutic doses. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013
A Silicon Nanowire‐Based Electrochemical Sensor with High Sensitivity and Electrocatalytic Activity
Authors: Su Shao , Wei Xinpan , Guo Yuanyuan , Zhong Yiling , Su Yuanyuan , Huang Qing , Fan Chunhai , He Yao
Published: February 2013

A new kind of silicon nanowire (SiNWs)‐based nanoelectrode assembly, a gold‐nanoparticle‐decorated silicon nanowire array (AuNPs@SiNWsAr), is employed for the construction of high‐performance electrochemical sensors. Significantly, the electrochemical nanosensors are capable of sensitive detection of various electroactive molecules (e.g., dopamine (DA), ascorbic acid (AA), hydrogen peroxide (H2O2), and glucose). Further, DA molecules loaded on the surface of AuNPs@SiNWsAr preserve stable high electroactivity overnight without special protection, while free DA molecules may lose their biological activity due to severe oxidization in ambient environment. These findings may offer new opportunities for the design of high‐performance electrochemical nanosensors with high sensitivity and robust stability.
Synthesis of Fluorinated Graphene Oxide and its Amphiphobic Properties
Authors: Mathkar Akshay , Narayanan T. N. , Alemany Lawrence B. , Cox Paris , Nguyen Patrick , Gao Guanhui , Chang Patricia , Romero‐Aburto Rebeca , Mani Sendurai A. , Ajayan P. M.
Published: February 2013

The richly functionalized basal plane bonded to polar organic moieties makes graphene oxide (GO) innately hydrophilic. Here, a methodology to synthesize fluorinated graphene oxide by oxidizing the basal plane of fluorinated graphite, allowing for tunable hydrophobicity of GO, is reported. Fluorine exists as tertiary alkyl fluorides covalently bonded to graphitic carbons, and using magic‐angle spinning (MAS) 13C NMR as a primary tool chemical structures for the two types of synthesized fluorinated graphene oxides (FGOs) with significantly different fluorine contents are proposed. The low surface energy of the C–F bond drastically affects GO's wetting behavior, leading to amphiphobicity in its highly fluorinated form. Ease of solution processing enables the fabrication of inks that are spray‐painted on various porous/non‐porous substrates. These coatings maintain amphiphobicity for solvents with surface tensions down to 59 dyn/cm, thus bypassing existing lithographic means to create similar surfaces. The approach towards fluorinating GO and fabricating graphene‐based surfaces with tunable wettability opens the path towards unique, accessible, carbon‐based amphiphobic coatings.
Fluorinated Eu‐Doped SnO2 Nanostructures with Simultaneous Phase and Shape Control and Improved Photoluminescence
Authors: Wang Hongkang , Wang Yu , Kershaw Stephen V. , Hung Tak Fu , Xu Jun , Rogach Andrey L.
Published: February 2013

Fluorinated Eu‐doped SnO2 nanostructures with tunable morphology (shuttle‐like and ring‐like) are prepared by a hydrothermal method, using NaF as the morphology controlling agent. X‐ray diffraction, field‐emission scanning electron microscopy, high‐resolution transmission electron microscopy, X‐ray photoelectron spectroscopy, and energy dispersive spectroscopy are used to characterize their phase, shape, lattice structure, composition, and element distribution. The data suggest that Eu3+ ions are uniformly embedded into SnO2 nanocrystallites either through substitution of Sn4+ ions or through formation of Eu‐F bonds, allowing for high‐level Eu3+ doping. Photoluminescence features such as transition intensity ratios and Stark splitting indicate diverse localization of Eu3+ ions in the SnO2 nanoparticles, either in the crystalline lattice or in the grain boundaries. Due to formation of Eu‐F and Sn‐F bonds, the fluorinated surface of SnO2 nanocrystallites efficiently inhibits the hydroxyl quenching effect, which accounts for their improved photoluminescence intensity.
Spirometric reference values in urban children in madagascar: Poverty is a risk factor for low lung function
Authors: Wolff Peter Th. , Arison Lala , Rahajamiakatra Abel , Raserijaona Francis , Niggemann Bodo
Published: February 2013

Background

Studies about children with respiratory diseases in Africa are impeded by the dearth of reliable data for the vast majority of countries on the continent. This study was conducted to establish representative reference values, therefore allowing a more accurate evaluation of lung function in Malagasy children.

Methods

One thousand two hundred thirty‐six students from three public and five private schools aged 8–12 years were recruited. A total of 1,093 children were healthy, had a valid lung function measurement and were thus deemed evaluable for this study. Lung function data were collected on consecutive days in Antananarivo, Madagascar's capital, using spirometry and a modified International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire.

Results

The lung volumes found were substantially lower compared to Caucasian and African equations. The mean Z‐score (Stanojevic) for the forced vital capacity (FVC) found was −1.45 and −0.93 for the forced expiratory volume in 1 sec (FEV1) with significant differences between private and public schools (FVC: P = 0.0023, FEV1: P = 0.0004).

Conclusions

The equations established for school children in Madagascar's capital Antananarivo showed lung function values were lower than reference values for the same age group seen not only in European, but also in African American and African children. The unique ethnicity of the Malagasy people, which combines Southeast‐Asian with substantial African influences, the heavy burden of pollution and poverty may explain these differences. Pediatr Pulmonol. 2014; 49:76–83. © 2013 Wiley Periodicals, Inc.
Evolution of crystallins for a role in the vertebrate eye lens
Authors: Slingsby Christine , Wistow Graeme J. , Clark Alice R.
Published: February 2013

The camera eye lens of vertebrates is a classic example of the re‐engineering of existing protein components to fashion a new device. The bulk of the lens is formed from proteins belonging to two superfamilies, the α‐crystallins and the βγ‐crystallins. Tracing their ancestry may throw light on the origin of the optics of the lens. The α‐crystallins belong to the ubiquitous small heat shock proteins family that plays a protective role in cellular homeostasis. They form enormous polydisperse oligomers that challenge modern biophysical methods to uncover the molecular basis of their assembly structure and chaperone‐like protein binding function. It is argued that a molecular phenotype of a dynamic assembly suits a chaperone function as well as a structural role in the eye lens where the constraint of preventing protein condensation is paramount. The main cellular partners of α‐crystallins, the β‐ and γ‐crystallins, have largely been lost from the animal kingdom but the superfamily is hugely expanded in the vertebrate eye lens. Their structures show how a simple Greek key motif can evolve rapidly to form a complex array of monomers and oligomers. Apart from remaining transparent, a major role of the partnership of α‐crystallins with β‐ and γ‐crystallins in the lens is to form a refractive index gradient. Here, we show some of the structural and genetic features of these two protein superfamilies that enable the rapid creation of different assembly states, to match the rapidly changing optical needs among the various vertebrates.
The PSV That Did Not Fail—Misconceptions About PSVs
Authors: Hagey Emmanuelle
Published: February 2013

Pressure relief devices generally represent the last line of defense for a pressure vessel in a chemical plant during abnormal situations. The article title comes from the numerous times the author heard that “a pressure safety device had failed” when the person making this statement was in essence thinking that “the pressure safety device had opened.” The use of the term “failure” conveys the impression that something was wrong about this safety device, when in fact it had done exactly what it was supposed to do. And although the consequences of the device activation may cause an undesirable event such as plant shutdown, it is not a relief system failure. Some misconceptions are so widely spread among plant engineers that it is very hard (especially for young engineers) to challenge and deviate from that common “knowledge.” It is not the goal of this article to provide in‐depth design considerations for pressure safety devices. The objective of this article is to present some key points that “every plant engineer should know” about the pressure safety valve lifecycle, from design to installation and maintenance. © 2013 American Institute of Chemical Engineers Process Saf Prog 32: 84–89, 2013
Ignition Characteristics for Methane‐Air Mixtures atVarious Initial Temperatures
Authors: Zhang Qi , Li Wei
Published: February 2013

This study was aimed at determining the effects of initial temperature on minimum ignition energy (MIE) and combustion parameters of methane‐air mixtures. A series experiments were carried out with an ignition energy measurement system and two combustion vessels (5 L and 20 L). The results described in this article include: (a) the MIE of methane‐air mixtures reached their lowest values at a concentration of 8.5%, instead of 9.5% stoichiometric concentration, (b) the MIE of methane‐air mixtures decreases as initial temperature increases, (c) the combustion temperature and maximum rate of combustion temperature rise of methane‐air mixtures decrease as initial temperature increases, and (d) the combustion pressure of methane‐air mixtures decreases as initial temperature increases. © 2013 American Institute of Chemical Engineers Process Saf Prog 32: 37–41, 2013
Enhanced efficiency in InGaN‐based photovoltaic devices combined with nanocrystalline Bi2O3/P3HT heterojunction structures
Authors: Lai Chun‐Feng , Chang Chung‐Chieh , Wen Min‐Hsueh , Lin Chung‐Kwei , Wu Mau‐Kuen
Published: February 2013

This study experimentally investigates the ability of Bi2O3/P3HT heterojunction thin films to improve the power‐conversion efficiency of InGaN‐based photovoltaic (PV) devices. InGaN‐based PV devices combined with Bi2O3/P3HT heterojunctions were prepared using the pulsed laser deposition method. The Bi2O3/P3HT heterojunction creates carriers that combine with excitons through the light‐absorbance process, which enhances the power‐conversion efficiency of InGaN PV devices by approximately 36%. Thus, these Bi2O3/P3HT heterojunctions can provide an efficiency improvement in InGaN PV devices and other related solar‐cell applications.
Tailoring broadband gain incorporating quantum dot fluctuations for a GaInNAs semiconductor optical amplifier
Authors: Sun X. , Vogiatzis N. , Rorison J. M.
Published: February 2013

It has been observed experimentally that the band edge photoluminescence (PL) of GaxIn1‐xNyAs1‐yquantum well (QW) materials is broadened due to compositional fluctuations with N distribution. These fluctuations can be modelled as quantum dot‐like region at the conduction band minimum in as‐grown GaInNAs/GaAs QWs. We have developed a rate‐equation approach to describe the distribution of electrons in the QW and QD‐like fluctuations which include the carrier recombination from both the conventional 2D QW layer and the inhomogeneous dot‐like fluctuations. The electron dynamics in the QW and QDs states are examined and the resulting carrier population and broadband gain is derived for a single QW. This is then applied to the design of a broadband gain multi‐QW semiconductor optical amplifier (SOA). (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Statistical Process Control‐Based Intrusion Detection and Monitoring
Authors: Park Yongro , Baek Seung Hyun , Kim Seong‐Hee , Tsui Kwok‐Leung
Published: February 2013

Intrusion detection systems have a vital role in protecting computer networks and information systems. In this article, we applied a statistical process control (SPC)–monitoring concept to a certain type of traffic data to detect a network intrusion. We proposed an SPC‐based intrusion detection process and described it and the source and the preparation of data used in this article. We extracted sample data sets that represent various situations, calculated event intensities for each situation, and stored these sample data sets in the data repository for use in future research. This article applies SPC charting methods for intrusion detection. In particular, it uses the basic security module host audit data from the MIT Lincoln Laboratory and applies the Shewhart chart, the cumulative sum chart, and the exponential weighted moving average chart to detect a denial of service intrusion attack. The case study shows that these SPC techniques are useful for detecting and monitoring intrusions. Copyright © 2013 John Wiley & Sons, Ltd.
Chemical treatment of wood fiber and its reinforced unsaturated polyester composites
Authors: Zhang Hui‐hui , Cui Yihua , Zhang Zhidan
Published: February 2013

In order to enhance the interfacial adhesion between wood fiber and an unsaturated polyester matrix (UPE), acrylic acid (acrylic acid)/poly(methyl methacrylate), and (acrylic acid)/silanization (AAS) were used to treat the wood fibers. The mechanical properties and the impact fracture surfaces of the prepared composites were measured and characterized, and the fracture mechanism of these kinds of composites was analyzed. The results showed that the AAS composites possessed the optimum comprehensive mechanical properties. When the weight fraction of wood fiber was 16%, the flexural strength and flexural modulus of the AAS composites were increased by 28.9 and 51.8%, respectively, compared to those of untreated composites. The highest tensile strength and lowest water absorption were also noted for AAS composites. These composites possessed the strongest interfacial adhesion between wood fiber and the UPE matrix. J. VINYL ADDIT. TECHNOL., 19:18–24, 2013. © 2013 Society of Plastics Engineers
Effects of halloysite nanotubes and kaolin loading on the tensile, swelling, and oxidative degradation properties of poly(vinyl alcohol)/chitosan blends
Authors: Ismail Hanafi , Khoo Wee Shen , Ariffin Azlan
Published: February 2013

[Halloysite nanotubes (HNT)]‐filled and kaolin filled composite films based on poly(vinyl alcohol) (PVA)/chitosan (CS) blend were prepared via solution casting method. Tensile properties, fracture morphology, FTIR spectra, thermal stability, swelling properties, moisture absorption, and oxidative degradation of the composite films were investigated. Addition of 0.5 wt% of filler led to the optimum tensile properties of the films. Increased roughness and tearing in the fracture surface morphology supported the tensile results. The FTIR results indicated there were physical interactions present in the composite films. Thermal stability of the composite films differed slightly where PVA/CS/HNT composite films showed better thermal stability than PVA/CS/kaolin composite films. Moreover, the presence of HNT and kaolin fillers in the blend reduced the swelling and moisture absorption properties of the films. Finally, the composite films were degraded by using Fenton's reagent. Degradation percentage of the composite films decreased with increasing filler loading. J. VINYL ADDIT. TECHNOL., 19:55–64, 2013. © 2013 Society of Plastics Engineers
Carbon markets: a historical overview
Authors: Calel Raphael
Published: February 2013

The global carbon trade has in a short space of time grown into a market worth over $175 billion a year. The history of carbon markets is a great political success story, and today they form an integral part of international climate change policy. Yet we only have a very limited understanding of how well these markets work in practice. Studying the incoming evidence and piecing it together with past emissions trading experiences can teach us a lot about how carbon markets work, and how they can fail. This article reviews the history of emissions trading and the rise of carbon markets as a basis for better understanding what is happening now. Viewing these markets in a historical light reveals that many of the current problems have precedent, and that we are perhaps not learning enough from past experiences. If carbon market policies were more geared toward systematic evaluation, and more open to incorporating past lessons into new policy, carbon markets would stand a greater chance of helping achieve the transition to a low‐carbon economy. WIREs Clim Change 2013, 4:107–119. doi: 10.1002/wcc.208

This article is categorized under:

The Carbon Economy and Climate Mitigation > Policies, Instruments, Lifestyles, Behavior
High‐throughput molecular dynamics simulations: toward a dynamic view of macromolecular structure
Authors: Hospital Adam , Gelpi Josep Ll
Published: February 2013

Molecular dynamics (MD) simulation is nowadays the eligible theoretical technique to account for macromolecular flexibility. Molecular simulations, from ab initio to coarse‐grained representation levels, allow having a direct visualization of macromolecular dynamic behavior and its influence in molecular recognition. In the postgenomic era, where most bioinformatics studies should be performed genome‐wide, molecular simulations should not be an exception. However, moving MD simulations to the high‐throughput regime is not a trivial issue. High‐performance computing systems (highly parallel supercomputers or graphical processing units‐based systems) allow performing large and complex simulations at a significantly reduced time. Besides, data storage strategies have also been largely improved. However, system preparation and trajectory analysis are still performed almost manually and become highly limited by the need of human intervention. A number of projects, like Dynameomics, BioSimGrid, or MoDEL have addressed the issue of high‐throughput MD. Such initiatives have released tools that have meant a significant progress in the field. The extension of structural studies, mainly molecular simulations, to the high‐throughput regime, will allow matching genomic‐wide studies now performed.

This article is categorized under:

Molecular and Statistical Mechanics > Molecular Dynamics and Monte-Carlo Methods
Comparison of techniques for estimating evaporation from an irrigation water storage
Authors: McJannet D. L. , Cook F. J. , Burn S.
Published: February 2013

Key Points

Techniques for estimating evaporation were compared to measured values

Penman‐Monteith model performed well with local site data and wind function

Model predictions are sensitive to local variation in meteorological data
Joint interpretation of sequential pumping tests in unconfined aquifers
Authors: Mao Deqiang , Yeh Tian‐Chyi J. , Wan Li , Wen Jet‐Chau , Lu Wenxi , Lee Cheng‐Haw , Hsu Kuo‐Chin
Published: February 2013

Key Points

Joint interpretation of sequential pumping tests

Variably saturated flow assumption for flow in unconfined aquifers

Estimation of unsaturated parameters
Mechano‐sensing and transduction by endothelial surface glycocalyx: composition, structure, and function
Authors: Fu Bingmei M. , Tarbell John M.
Published: February 2013

The endothelial cells (ECs) lining every blood vessel wall are constantly exposed to the mechanical forces generated by blood flow. The EC responses to these hemodynamic forces play a critical role in the homeostasis of the circulatory system. To ensure proper EC mechano‐sensing and transduction, there are a variety of mechano‐sensors and transducers that have been identified on the EC surface, intra‐ and trans‐EC membrane and within the EC cytoskeleton. Among them, the most recent candidate is the endothelial surface glycocalyx (ESG), which is a matrix‐like thin layer covering the luminal surface of the EC. It consists of various proteoglycans, glycosaminoglycans, and plasma proteins, and is close to other prominent EC mechano‐sensors and transducers. The ESG thickness was found to be in the order of 0.1–1 µm by different visualization techniques and in different types of vessels. Detailed analysis on the electron microscopy (EM) images of the microvascular ESG revealed a quasi‐periodic substructure with the ESG fiber diameter of 10–12 and 20 nm spacing between adjacent fibers. Atomic force microscopy and optical tweezers were applied to investigate the mechanical properties of the ESG on the cultured EC monolayers and in solutions. Enzymatic degradation of specific ESG glycosaminoglycan components was used to directly elucidate the role of the ESG in EC mechano‐sensing and transduction by measuring the shear‐induced productions of nitric oxide and prostacyclin, two characteristic responses of the ECs to the flow. The unique location, composition, and structure of the ESG determine its role in EC mechano‐sensing and transduction. WIREs Syst Biol Med 2013, 5:381–390. doi: 10.1002/wsbm.1211

This article is categorized under:

Models of Systems Properties and Processes > Cellular Models

Biological Mechanisms > Cell Signaling

Physiology > Organismal Responses to Environment
Chemical Vapor Transport Reactions – A Historical Review
Authors: Binnewies Michael , Glaum Robert , Schmidt Marcus , Schmidt Peer
Published: February 2013

Since their first recognition in mineral forming processes some 150 years ago chemical vapor transport reactions (CVTR) have attracted continuous scientific interest. Due to the pioneering work of Harald Schäfer quantitative understanding and exploitation of transport reactions for crystal growth, synthesis, investigation of high‐temperature gas species, and thermodynamic studies have become possible. Renewed interest in CVT is triggered by the demand of material sciences for novel compounds with tailor‐made physical properties and by the need for efficient recycling strategies for various metals from industrial waste.
Gender differences in first-episode psychosis at 5-year follow-up – two different courses of disease? Results from the OPUS study at 5-year follow-up
Authors: Thorup A. , Albert N. , Bertelsen M. , Petersen L. , Jeppesen P. , Le Quack P. , Krarup G. , Jørgensen P. , Nordentoft M.
Published: February 2013

Objective

Gender differences in psychosis have been investigated, and the results have contributed to a better understanding of the disease, but many questions are unanswered. In clinical terms, women and men with psychosis differ in terms of access to social support, tendency of substance abuse, level of functioning and symptom patterns. We aimed to investigate how gender differences at onset of psychosis develop during the first 5 years of treatment.

Method

A total of 578 patients with a first-episode psychosis in the schizophrenia spectrum were included in the Danish OPUS trial – a randomized clinical trial comparing 2 years of intensive early-intervention programme with standard treatment. All patients were assessed with validated instruments at inclusion, and after 2 and 5 years. Data were analysed for significant gender differences.

Results

Males have significantly higher levels of negative symptoms at all times, and are more likely to live alone and suffer from substance abuse. Females reach higher levels of social functioning at follow-up, and show a greater tendency to be employed or in education than males. Markedly more women than men live with children. More women than men reach a state of recovery and are more compliant with medication.

Conclusion

There are significant gender differences at 2- and 5-year follow-up in this large cohort of first-episode psychotic patients. Males and females show different symptomatology and different levels of social functioning.
Self-limiting and regenerative dynamics of perturbation growth on a vortex column
Authors: Hussain Fazle , Stout Eric
Published: February 2013

We study the mechanisms of centrifugal instability and its eventual self-limitation, as well as regenerative instability on a vortex column with a circulation overshoot (potentially unstable) via direct numerical simulations of the incompressible Navier–Stokes equations. The perturbation vorticity (${\boldsymbol{\omega} }^{\prime } $) dynamics are analysed in cylindrical ($r, \theta , z$) coordinates in the computationally accessible vortex Reynolds number, $\mathit{Re}({\equiv }\mathrm{circulation/viscosity} )$, range of 500–12 500, mostly for the axisymmetric mode (azimuthal wavenumber $m= 0$). Mean strain generates azimuthally oriented vorticity filaments (i.e. filaments with azimuthal vorticity, ${ \omega }_{\theta }^{\prime } $), producing positive Reynolds stress necessary for energy growth. This ${ \omega }_{\theta }^{\prime } $ in turn tilts negative mean axial vorticity, $- {\Omega }_{z} $ (associated with the overshoot), to amplify the filament, thus causing instability. (The initial energy growth rate (${\sigma }_{r} $), peak energy (${G}_{\mathit{max}} $) and time of peak energy (${T}_{p} $) are found to vary algebraically with $\mathit{Re}$.) Limitation of vorticity growth, also energy production, occurs as the filament moves the overshoot outward, hence lessening and shifting $\vert {- }{\Omega }_{z} \vert $, while also transporting the core $+ {\Omega }_{z} $, to the location of the filament. We discover that a basic change in overshoot decay behaviour from viscous to inviscid occurs at $Re\sim 5000$. We also find that the overshoot decay time has an asymptotic limit of 45 turnover times with increasing $\mathit{Re}$. After the limitation, the filament generates negative Reynolds stress, concomitant energy decay and hence self-limitation of growth; these inviscid effects are enhanced further by viscosity. In addition, the filament transports angular momentum radially inward, which can produce a new circulation overshoot and renewed instability. Energy decays at the $\mathit{Re}$ studied, but, at higher $\mathit{Re}$, regenerative growth of energy is likely due to the renewed mean shearing. New generation of overshoot and Reynolds stress is examined using a helical ($m= 1$) perturbation. Regenerative energy growth, possibly resulting in even vortex breakup, can be triggered by this new overshoot at practical $\mathit{Re}$ (${\sim }1{0}^{6} $ for trailing vortices), which are currently beyond the computational capability.
The role of large-scale vortical structures in transient convective heat transfer augmentation
Authors: Hubble David O. , Vlachos Pavlos P. , Diller Tom E.
Published: February 2013

The physical mechanism by which large-scale vortical structures augment convective heat transfer is a fundamental problem of turbulent flows. To investigate this phenomenon, two separate experiments were performed using simultaneous heat transfer and flow field measurements to study the vortex–wall interaction. Individual vortices were identified and studied both as part of a turbulent stagnation flow and as isolated vortex rings impacting on a surface. By examining the temporal evolution of both the flow field and the resulting heat transfer, it was observed that the surface thermal transport was governed by the transient interaction of the vortical structure with the wall. The magnitude of the heat transfer augmentation was dependent on the instantaneous strength, size and position of the vortex relative to the boundary layer. Based on these observations, an analytical model was developed from first principles that predicts the time-resolved surface convection using the transient properties of the vortical structure during its interaction with the wall. The analytical model was then applied, first to the simplified vortex ring model and then to the more complex stagnation region experiments. In both cases, the model was able to accurately predict the time-resolved convection resulting from the vortex interactions with the wall. These results reveal the central role of large-scale turbulent structures in the augmentation of thermal transport and establish a simple model for quantitative predictions of transient heat transfer.
On non-existence of steady periodic solutions of the Prandtl equations
Authors: Renardy Michael
Published: February 2013

We prove that periodic solutions of the steady Prandtl equations do not exist on a stationary boundary. On a moving boundary, there are no solutions with a monotone velocity profile.
Testing Potential New Sites for Optical Telescopes in Australia
Authors: Hotan C. E. , Tingay S. J. , Glazebrook K.
Published: February 2013

In coming years, Australia may find the need to build new optical telescopes to continue local programmes, contribute to global survey projects, and form a local multi-wavelength connection for the new radio telescopes being built. In this study, we refine possible locations for a new optical telescope by studying remotely sensed meteorological infrared data to ascertain expected cloud coverage rates across Australia, and combine these data with a digital elevation model using a geographic information system. We find that the best sites within Australia for building optical telescopes are likely to be on the highest mountains in the Hamersley Range in northwest Western Australia, while the MacDonnell Ranges in the Northern Territory may also be appropriate. We believe that similar seeing values to Siding Spring should be obtainable and with significantly more observing time at the identified sites. We expect to find twice as many clear nights as at current telescope sites. These sites are thus prime locations for future on-site testing.
The Murchison Widefield Array: The Square Kilometre Array Precursor at Low Radio Frequencies
Authors: Tingay S. J. , Goeke R. , Bowman J. D. , Emrich D. , Ord S. M. , Mitchell D. A. , Morales M. F. , Booler T. , Crosse B. , Wayth R. B. , Lonsdale C. J. , Tremblay S. , Pallot D. , Colegate T. , Wicenec A. , Kudryavtseva N. , Arcus W. , Barnes D. , Bernardi G. , Briggs F. , Burns S. , Bunton J. D. , Cappallo R. J. , Corey B. E. , Deshpande A. , Desouza L. , Gaensler B. M. , Greenhill L. J. , Hall P. J. , Hazelton B. J. , Herne D. , Hewitt J. N. , Johnston-Hollitt M. , Kaplan D. L. , Kasper J. C. , Kincaid B. B. , Koenig R. , Kratzenberg E. , Lynch M. J. , Mckinley B. , Mcwhirter S. R. , Morgan E. , Oberoi D. , Pathikulangara J. , Prabu T. , Remillard R. A. , Rogers A. E. E. , Roshi A. , Salah J. E. , Sault R. J. , Udaya-Shankar N. , Schlagenhaufer F. , Srivani K. S. , Stevens J. , Subrahmanyan R. , Waterson M. , Webster R. L. , Whitney A. R. , Williams A. , Williams C. L. , Wyithe J. S. B.
Published: February 2013

The Murchison Widefield Array (MWA) is one of three Square Kilometre Array Precursor telescopes and is located at the Murchison Radio-astronomy Observatory in the Murchison Shire of the mid-west of Western Australia, a location chosen for its extremely low levels of radio frequency interference. The MWA operates at low radio frequencies, 80–300 MHz, with a processed bandwidth of 30.72 MHz for both linear polarisations, and consists of 128 aperture arrays (known as tiles) distributed over a ~3-km diameter area. Novel hybrid hardware/software correlation and a real-time imaging and calibration systems comprise the MWA signal processing backend. In this paper, the as-built MWA is described both at a system and sub-system level, the expected performance of the array is presented, and the science goals of the instrument are summarised.
Influences of Galaxy Interactions on AGN Activity
Authors: Deng Xin-Fa , Yu Guisheng , Jiang Peng
Published: February 2013

Using two volume-limited Main galaxy samples of the Sloan Digital Sky Survey Data Release 7 , we explore influences of galaxy interactions on AGN activity. It is found that in the faint volume-limited sample, paired galaxies have a slightly higher AGN fraction than isolated galaxies, whereas in the luminous volume-limited sample, an opposite trend can be observed. The significance is <1σ. Thus, we do not observe strong evidence that interactions or mergers likely trigger the AGN activity.
The impact of a 16-week dietary intervention with prescribed amounts of whole-grain foods on subsequent, elective whole grain consumption
Authors: Brownlee Iain A. , Kuznesof Sharron A. , Moore Carmel , Jebb Susan A. , Seal Chris J.
Published: February 2013

Previous (mainly population-based) studies have suggested the health benefits of the elective, lifelong inclusion of whole-grain foods in the diet, forming the basis for public health recommendations to increase whole grain consumption. Currently, there is limited evidence to assess how public health recommendations can best result in longer-term improvements in dietary intake. The present study aimed to assess the impact of a previous 16-week whole-grain intervention on subsequent, elective whole grain consumption in free-living individuals. Participants completed a postal FFQ 1, 6 and 12 months after the end of the whole-grain intervention study period. This FFQ included inputs for whole-grain foods commonly consumed in the UK. Whole grain consumption was significantly higher (approximately doubled) in participants who had received whole-grain foods during the intervention (P< 0·001) compared with the control group who did not receive whole-grain foods during the intervention. This increased whole grain consumption was lower than whole grain intake levels required by participants during the intervention period between 60 and 120 g whole grains/d. Aside from a significant increase (P< 0·001) in NSP consumption compared with control participants (mean increase 2–3 g/d), there were no obvious improvements to the pattern of foods of the intervention group. The results of the present study suggest that a period of direct exposure to whole-grain foods in non-habitual whole-grain food consumers may benefit subsequent, elective dietary patterns of whole grain consumption. These findings may therefore aid the development of future strategies to increase whole grain consumption for public health and/or food industry professionals.
The natural absence of RPA1N domain did not impair Leishmania amazonensis RPA-1 participation in DNA damage response and telomere protection
Authors: DA SILVEIRA RITA DE CÁSSIA VIVEIROS , DA SILVA MARCELO SANTOS , NUNES VINÍCIUS SANTANA , PEREZ ARINA MARINA , CANO MARIA ISABEL NOGUEIRA
Published: February 2013

We have previously shown that the subunit 1 of Leishmania amazonensis RPA (LaRPA-1) alone binds the G-rich telomeric strand and is structurally different from other RPA-1. It is analogous to telomere end-binding proteins described in model eukaryotes whose homologues were not identified in the protozoan´s genome. Here we show that LaRPA-1 is involved with damage response and telomere protection although it lacks the RPA1N domain involved with the binding with multiple checkpoint proteins. We induced DNA double-strand breaks (DSBs) in Leishmania using phleomycin. Damage was confirmed by TUNEL-positive nuclei and triggered a G1/S cell cycle arrest that was accompanied by nuclear accumulation of LaRPA-1 and RAD51 in the S phase of hydroxyurea-synchronized parasites. DSBs also increased the levels of RAD51 in non-synchronized parasites and of LaRPA-1 and RAD51 in the S phase of synchronized cells. More LaRPA-1 appeared immunoprecipitating telomeres in vivo and associated in a complex containing RAD51, although this interaction needs more investigation. RAD51 apparently co-localized with few telomeric clusters but it did not immunoprecipitate telomeric DNA. These findings suggest that LaRPA-1 and RAD51 work together in response to DNA DSBs and at telomeres, upon damage, LaRPA-1 works probably to prevent loss of single-stranded DNA and to assume a capping function.
A coordination-based CPG structure for 3D walking control
Authors: Huang Weiwei , Chew Chee-Meng , Hong Geok-Soon
Published: February 2013

In most of our daily motion tasks, the coordination between limbs is very crucial for successful execution of the tasks. In this paper, coordination among oscillators controlling in Cartesian space is studied to control bipedal walking. In our method, phase adjustment among oscillators is considered as one of the key issues to achieve coordination. A new phase adjustment method is proposed. With this method, an oscillator is able to coordinate other oscillators and maintain a desired phase relationship. This property is important for the walking control especially when external perturbations are given. To simplify the relationship between oscillators in a central pattern generator (CPG), a hierarchical CPG structure is adopted, where a main oscillator will be used to adjust other oscillators. In the simulation, the walking motion controlled by the CPG controller converges to a stable pattern even with external perturbations. We have implemented the controller in both the simulation model and real hardware robot.
On the automatic compilation of e-learning models to planning
Authors: Garrido Antonio , Fernández Susana , Morales Lluvia , Onaindía Eva , Borrajo Daniel , Castillo Luis
Published: February 2013

This paper presents a general approach to automatically compile e-learning models to planning, allowing us to easily generate plans, in the form of learning designs, by using existing domain-independent planners. The idea is to compile, first, a course defined in a standard e-learning language into a planning domain, and, second, a file containing students learning information into a planning problem. We provide a common compilation and extend it to three particular approaches that cover a full spectrum of planning paradigms, which increases the possibilities of using current planners: (i) hierarchical, (ii) including PDDL (Planning Domain Definition Language) actions with conditional effects and (iii) including PDDL durative actions. The learning designs are automatically generated from the plans and can be uploaded, and subsequently executed, by learning management platforms. We also provide an extensive analysis of the e-learning metadata specification required for planning, and the pros and cons on the knowledge engineering procedures used in each of the three compilations. Finally, we include some qualitative and quantitative experimentation of the compilations in several domain-independent planners to measure its scalability and applicability.
Past tense productivity in Dutch children with and without SLI: the role of morphophonology and frequency
Authors: RISPENS JUDITH E. , DE BREE ELISE H.
Published: February 2013

This study focuses on morphophonology and frequency in past tense production. It was assessed whether Dutch five- and seven-year-old typically developing (TD) children and eight-year-old children with specific language impairment (SLI) produce the correct allomorph in regular, irregular, and novel past tense formation. Type frequency of the allomorph, token frequency and phonotactic probability (PP) of the novel verb form are considered. The results showed all groups were sensitive to the phonological cue. PP did not contribute to past tense inflection of novel verbs in any of the groups, but type frequency did in all three groups. Only the seven-year-old typically developing children relied on token frequency for inflection of regulars. The findings point to an important role of phonology and frequency in past tense acquisition for both TD children and children with SLI. We discuss how the SLI performance pattern relates to theories on SLI.
Material Scaffolds in Numbers and Time
Authors: Overmann Karenleigh A.
Published: February 2013

The present article develops a framework for interpreting Upper Palaeolithic artefacts from an analysis of material complexity, numeration systems and timekeeping using cultural categorizations, insights on the emergence of number terms in language, and the astronomy practices of 33 contemporary hunter-gatherer societies. Our key findings suggest that astronomy originates in the ability to estimate and infer contextual relations among natural phenomena and transitions from these natural associations to material representations and cognitive technologies that mediate conceptual apprehensions of time as a substance that can be quantified. Given that artefacts may act as scaffolds for explicit concepts of numbers, and numbers scaffold explicit concepts of time, prehistoric artefacts such as the Blombos Cave beads (c. 75,000 bp), Abri Blanchard and Cellier artefacts (c. 28,000 bp), and plaque from Grotte du Taï (c. 14,000 bp) may represent similar scaffolding and conceptual development in numbers and time. It is proposed that the prehistoric societies making these artefacts possessed, in addition to material complexity, the abilities to express quantities in language and to use material externalization and cognitive technologies. Furthermore, the Abri Blanchard artefact is proposed to represent externalized working memory, a very modern interaction between mind and material culture.
Treatment of bipolar depression
Authors: Musetti Laura , Del Grande Claudia , Marazziti Donatella , Dell'Osso Liliana
Published: February 2013

Depressive symptoms and episodes dominate the long-term course of bipolar disorder and are associated with high levels of disability and an increased risk of suicide. However, the treatment of bipolar depression has been poorly investigated in comparison with that of manic episodes and unipolar major depressive disorder. The goal of treatment in bipolar depression is not only to achieve full remission of acute symptoms, but also to avoid long-term mood destabilization and to prevent relapses. A depressive presentation of bipolar disorder may often delay the appropriate management and, thus, worsen the long-term outcome. In these cases, an accurate screening for diagnostic indicators of a possible bipolar course of the illness should guide the therapeutic choices, and lead to prognostic improvement. Antidepressant use is still the most controversial issue in the treatment of bipolar depression. Despite inconclusive evidence of efficacy and tolerability, this class of agents is commonly prescribed in acute and long-term treatment, often in combination with mood stabilizers. In this article, we review available treatment options for bipolar depression, and we shall provide some suggestions for the management of the different presentations of depression in the course of bipolar disorder.
Effects of Stereotype Threat, Perceived Discrimination, and Examiner Race on Neuropsychological Performance: Simple as Black and White?
Authors: Thames April D. , Hinkin Charles H. , Byrd Desiree A. , Bilder Robert M. , Duff Kimberley J. , Mindt Monica Rivera , Arentoft Alyssa , Streiff Vanessa
Published: February 2013

The purpose of the current study was to examine the predictive roles of stereotype threat and perceived discrimination and the mediating role of examiner-examinee racial discordance on neuropsychological performance in a non-clinical sample of African American and Caucasian individuals. Ninety-two African American (n = 45) and Caucasian (n = 47) adults were randomly assigned to either a stereotype threat or non-threat condition. Within each condition, participants were randomly assigned to either a same race or different race examiner. All participants underwent neuropsychological testing and completed a measure of perceived discrimination. African Americans in the stereotype threat condition performed significantly worse on global NP (Mz = −.30, 95% confidence interval [CI] [−0.07, −0.67] than African Americans in the non-threat condition (Mz = 0.09, CI [0.15, 0.33]. African Americans who reported high levels of perceived discrimination performed significantly worse on memory tests when tested by an examiner of a different race, Mz = −1.19, 95% CI [−1.78, −.54], than African Americans who were tested by an examiner of the same race, Mz = 0.24, 95% CI [−0.24, 0.72]. The current study underscores the importance of considering the role of contextual variables in neuropsychological performance, as these variables may obscure the validity of results among certain racial/ethnic groups. (JINS, 2013, 19, 1–10)
Failure of the Hasse principle on general surfaces
Authors: Hassett Brendan , Várilly-Alvarado Anthony
Published: February 2013

We show that transcendental elements of the Brauer group of an algebraic surface can obstruct the Hasse principle. We construct a general $K 3$ surface $X$ of degree $2$ over $ \mathbb{Q} $, together with a 2-torsion Brauer class $\alpha $ that is unramified at every finite prime, but ramifies at real points of $X$. With motivation from Hodge theory, the pair $(X, \alpha )$ is constructed from a double cover of ${ \mathbb{P} }^{2} \times { \mathbb{P} }^{2} $ ramified over a hypersurface of bidegree $(2, 2)$.
Boundaries of instability zones for symplectic twist maps
Authors: Arnaud M.-C.
Published: February 2013

Very few things are known about the curves that are at the boundary of the instability zones of symplectic twist maps. It is known that in general they have an irrational rotation number and that they cannot be KAM curves. We address the following questions. Can they be very smooth? Can they be non-${C}^{1} $?

Can they have a Diophantine or a Liouville rotation number? We give a partial answer for${C}^{1} $and${C}^{2} $twist maps.

In Theorem 1, we construct a${C}^{2} $symplectic twist map$f$of the annulus that has an essential invariant curve$\Gamma $such that

$\bullet $ $\Gamma $is not differentiable;

$\bullet $the dynamics of${f}_{\vert \Gamma } $is conjugated to the one of a Denjoy counter-example;

$\bullet $ $\Gamma $is at the boundary of an instability zone for$f$.

Using the Hayashi connecting lemma, we prove in Theroem 2 that any symplectic twist map restricted to an essential invariant curve can be embedded as the dynamics along a boundary of an instability zone for some${C}^{1} $symplectic twist map.