bluuebunny/crossref_metadata_2025 huggingface dataset:
Dietary and lifestyle characteristics associated with normal-weight obesity: the National FINRISK 2007 Study
Authors: Männistö Satu , Harald Kennet , Kontto Jukka , Lahti-Koski Marjaana , Kaartinen Niina E. , Saarni Suoma E. , Kanerva Noora , Jousilahti Pekka
Published: November 2013

The aim of the present study was to compare the lifestyle (leisure-time physical activity, smoking habits and alcohol consumption) and dietary (energy-yielding nutrients, dietary fibre and foods) factors of Finns with a new syndrome called normal-weight obesity (NWO) with those of lean and overweight Finns. The representative population-based study included 4786 participants (25–74 years) from the National FINRISK 2007 Study with a health examination and questionnaires. Food intake was assessed using a validated FFQ. NWO was defined to include those with a normal BMI ( < 25 kg/m2) but excessive body fat (for men ≥ 20 % and for women ≥ 30 %) according to WHO definitions. The proportion of participants with a normal BMI was 28 % in men and 42 % in women. Of these, 34 % of the men and 45 % of the women had the NWO syndrome (among all the participants, 10 and 19 %, respectively). The waist circumference of the NWO participants was between that of the lean and overweight participants. Some potential risk factors, such as physical inactivity, (ex)-smoking and alcohol consumption, were related to NWO. In general, the intakes of energy-yielding nutrients were not associated with NWO. Instead, some healthy dietary factors (e.g. low intakes of meat and soft drinks) as well as unhealthy factors (e.g. low intakes of root vegetables, cereals and fish and high intake of confectionery) were related to NWO. The findings might explain why the NWO participants were of normal weight, but had an excessive body fat percentage. In conclusion, the proportion of normal-weight participants with an excessive body fat percentage was surprisingly high. The identification of NWO people may be of importance because although they appear lean, they have some unhealthy lifestyle and dietary habits related to obesity and overall health.
Association between energy-dense food consumption at 2 years of age and diet quality at 4 years of age
Authors: Vilela Sofia , Oliveira Andreia , Ramos Elisabete , Moreira Pedro , Barros Henrique , Lopes Carla
Published: November 2013

The present study aimed to evaluate the association between the consumption of energy-dense foods at 2 years of age and the consumption of foods and diet quality at 4 years of age. The sample included 705 children evaluated at 2 and 4 years of age, as part of the population-based birth cohort Generation XXI (Porto, Portugal). Data on sociodemographic and lifestyle factors of both children and mothers were collected by face-to-face interviews. The weight and height of children were measured by trained professionals. Based on FFQ, four energy-dense food groups were defined: soft drinks; sweets; cakes; salty snacks. A healthy eating index was developed using the WHO dietary recommendations for children (2006) aged 4 years. The associations were evaluated through Poisson regression models. After adjustment for maternal age and education, child's carer, child's siblings and child's BMI, higher consumption of energy-dense foods at 2 years of age was found to be associated with higher consumption of the same foods 2 years later. An inverse association was found between the intake ( ≥ median) of soft drinks (incidence rate ratio (IRR) = 0·74, 95 % CI 0·58, 0·95), salty snacks (IRR = 0·80, 95 % CI 0·65, 1·00) and sweets (IRR = 0·73, 95 % CI 0·58, 0·91) at 2 years of age and the consumption of fruit and vegetables at 4 years of age ( ≥ 5 times/d). Weekly and daily consumption of energy-dense foods at 2 years of age was associated with a lower healthy eating score at 4 years of age (IRR = 0·75, 95 % CI 0·58, 0·96; IRR = 0·56, 95 % CI 0·41, 0·77, respectively). The consumption of energy-dense foods at young ages is negatively associated with the diet quality of children a few years later.
Lehmer points and visible points on affine varieties over finite fields
Authors: MAK KIT-HO , ZAHARESCU ALEXANDRU
Published: November 2013

Let V be an absolutely irreducible affine variety over $\mathbb{F}_p$. A Lehmer point on V is a point whose coordinates satisfy some prescribed congruence conditions, and a visible point is one whose coordinates are relatively prime. Asymptotic results for the number of Lehmer points and visible points on V are obtained, and the distribution of visible points into different congruence classes is investigated.
The application of geometry corrections for Diffraction Strain Tomography (DST) analysis of a Ni-base superalloy blade
Authors: Baimpas Nikolaos , Xie Mengyin , Reinhard Christina , Korsunsky Alexander M.
Published: November 2013

X-ray diffraction is commonly used for non-destructive and precise quantitative determination of internal strain distributions. In recent years tomographic imaging has also been established as a powerful tool for precise non-destructive evaluation of internal structure in materials offering submicron resolution 3D imaging of density distributions. “Diffraction Strain tomography” (DST) concept (Korsunsky, Vorster et al. 2006) has been introduced as a means of tomographic reconstruction of two-dimensional internal strain distributions. The application of this approach during in situ loading has been subsequently demonstrated (Korsunsky et al., 2011). In the present study, similar acquisition strategy was used for diffraction data collection from a Ni-base superalloy turbine blade fabricated by DMLS (Direct Metal Laser Sintering, also sometimes referred to as DLD, Direct Laser Deposition). The experiment was conducted on beamline I12 (JEEP) at Diamond Light Source, UK. Each location within the object was multiply “sampled” (i.e. diffraction patterns were collected containing its contribution) by incident X-ray beams travelling through the sample at different angles. The setup of the beamline also allowed to acquire simultaneously a conventional (absorption tomography) reconstruction of the sample shape. The aim of the experiment was to obtain detailed information about the sample shape, structure, and state. The interpretation of diffraction tomography data requires precise calibration of the sample detector distance at different rotations and positions across the sample, and subsequent application of corrections to remove geometry-induced strain aberrations.
UMo/Al nuclear fuel plate behavior under thermal treatment (425-550°C)
Authors: Palancher H. , Bonnin A. , Colin C.V. , Nassif V. , Honkimäki V. , Jungwirth R. , Ritter C. , Champion G. , Calzavara Y.
Published: November 2013

Nuclear fuel plates based on a γU-Mo/Al mixture are proposed for research reactors. In this work their thermal behavior in the [425; 550°C] temperature range has been studied mainly by neutron and high energy X-ray diffraction. Even if complementary studies will be necessary, the kinetics of first the growth of the interaction layer between γU-Mo and Al and second of the γU-Mo destabilization have been accurately measured. This basic work should be helpful for defining manufacturing conditions for fuel plates with optimized composition.
The new Material Science Powder Diffraction beamline at ALBA Synchrotron
Authors: Fauth F. , Peral I. , Popescu C. , Knapp M.
Published: November 2013

The current report describes the installation and the preliminary commissioning of the Material Science Powder Diffraction (MSPD) beamline at the Spanish synchrotron ALBA-CELLS. The beamline is fully dedicated to powder diffraction techniques and consists of two experimental stations positioned in series: a High Pressure/Microdiffraction station and a High Resolution/High Throughput powder diffraction station.
XRD profile modeling approach tools to investigate the effect of charge location on hydration behavior in the case of metal exchanged smectite
Authors: Ammar Marwa , Oueslati Walid , Ben Rhaiem Hafsia , Ben Haj Amara Abdesslem
Published: November 2013

This work aims to investigate the hydration behavior and structural properties of two dioctahedral smectites with contrasting location charge (beidellite SbId-1 and montmorillonite SWy-2) according to the nature of the bivalent compensator heavy metal cations (i.e. Hg (II), Ni (II), Ba (II) and Mg (II)). This study is achieved using XRD profile modeling approach based on the simulation of the 00lreflection which allowed us to determine structural characteristics along the c* axis related to the nature, abundance, size, position and organization of exchangeable cation and water molecule in the interlamellar space along the c* axis. The obtained results show that a heterogeneous hydration behavior is systematically observed in all studied samples and the structural models, used to fit samples with tetrahedral charge, are more heterogeneous than smectite with an octahedral sheets substitution. In the case of exchanged beidellite specimen, the proposed models are described by a mixed layer structure with variable abundance containing respectively, dehydrated (0W), mono-hydrated (1W) and bihydrated (2W) layers. Whereas, in the case of the montmorillonite, the absence of 0W hydration state is noted.
Covalent modification of calcium hydroxy and fluoroapatite surface by grafting alkylphosphonate
Authors: Agougui Hassen , Aissa Abdallah , Debbabi Mongi
Published: November 2013

Calcium hydroxyl and fluoroapatite (CaHAp and CaFAp) were prepared in the presence of the 2-carboxyletylphosphonic acid (2-CEPA), by hydrothermal method. The incorporation of phosphonic acid within the apatite structure was confirmed by powder XRD, IR and MAS-NMR spectroscopies and SSA. The X-ray powder analysis showed that the cristallinity was not affected by the presence of organic moieties. IR spectroscopy showed new vibration modes related to phosphonate groups.31P MAS-NMR spectra exhibit new signals, assigned to the presence of organic phosphorus. Specific surface area (SSA) increases with increasing of phosphonate amount, especially for CaHAp. According to these results, a mechanism is proposed for the formation of two types of ionic interaction (-C-O-Ca) and (Ca-O-Porg).
Pressure effects on oxygen-deficient Ba-substituted cobaltites
Authors: Sikolenko V. , Efimov V.V. , Többens D. , Schorr S. , Ritter C. , Bushinsky M.V. , Troyanchuk I.O.
Published: November 2013

Neutron diffraction studies of the La0.5Ba0.5CoO2.8 at the different temperatures has been performed. This solid solution crystallizes in the cubic structure (Pm3m space group) and exhibits below TN ~ 250K G-type antifferomagnetic ordering. Applied pressure suppresses magnetic ordering. Anomalous changes of the lattice parameters under pressure have been found.
Crystal structure of RbBaVO4 and high-pressure modification of KCaVO4
Authors: Tarakina N.V. , Tyutyunnik A.P. , Dyachkova T.V. , Surat L.L. , Slobodin B.V. , Zubkov V.G.
Published: November 2013

The crystal structures of KCaVO4 and RbBaVO4, synthesized at high-pressure/high-temperature and by a conventional solid-state reaction, respectively, were determined using X-ray powder diffraction data. These compounds were found to have the β-K2SO4 structure type (space group Pnma, Z = 4) with parameters a = 7.2628(5) Å, b = 5.7258(4) Å, c = 9.6854(7) Å (KCaVO4), and a = 7.8887(1) Å, b = 5.9589(1) Å, c = 10.3958(2) Å (RbBaVO4). The unit cell volume of KCaVO4, 402.77(5) Å3, is significantly lower than for the low-temperature modification reported previously, 436.2 Å3. The difference can be explained by a pressure-induced phase transition to a more dense state resulting from the rotation of tetrahedra and the exchange of oxygen atoms from the first and second coordination spheres for potassium and calcium atoms.
Testing the Debye Function Approach on a Laboratory X-ray Powder Diffraction Equipment. A Critical Study.
Authors: Frison Ruggero , Cervellino Antonio , Cernuto Giuseppe , Guagliardi Antonietta , Masciocchi Norberto
Published: November 2013

Total Scattering Methods are nowadays widely used for the characterization of defective and nanosized materials. They commonly rely on highly accurate neutron and synchrotron diffraction data collected at dedicated beamlines. Here, we compare the results obtained on conventional laboratory equipment and synchrotron radiation when adopting the Debye Function Analysis method on a simple nanocrystalline material (a synthetic iron oxide with average particle size near to 10 nm). Such comparison, which includes the cubic lattice parameter, the sample stoichiometry and the microstructural (size-distribution) analyses, highlights the limitations, but also some strengthening points, of dealing with conventional powder diffraction data collections on nanocrystalline materials.
Interpreting Regimes of Memory
Authors: Dénes Iván Zoltán
Published: November 2013

This introduction gives a brief account of the conceptual framework and the topics of the case studies, especially the connection between the psychological concept of trauma applied in the social sciences and the characteristics of the historical analysis of traumatic events or processes, the link between the patterns of consolidation and the regimes of memory, and the context of the chosen case studies of this focus.
Mass Graves from the Civil War and the Franco Era in Spain: Once Forgotten, Now at the Heart of the Public Debate
Authors: Gelonch-Solé Josep
Published: November 2013

Since October 2000, mass graves from the Civil War and Franco's dictatorship have become the most visible issue of the process of recovery of historical memory in Spain, as a metaphor for digging up the traumatic past. This paper offers a historical reading of this process, pointing out the importance of recovering the buried bodies to give them a worthy burial, to restore their memory, and to allow families to complete their mourning. Mass graves have been the subject of different interventions: they have been located, marked and dignified, in some cases opened and the human remains exhumed. The graves, previously symbols of silence and oblivion are now sites of mourning and memory. In addition, many forgotten memories have been recovered. The victims of the war and the dictatorship have returned to the heart of the public debate, although not without controversy.
Making Democratic Political Culture
Authors: Zoltán Dénes Iván
Published: November 2013

The essay deals with the criterion and the distortion of making democratic political culture the basis of the democratic political community in the context of the traumatic historical experiences. The historical traumas of the communities may lead to a fluid or vacuum situation, a non-democratic consolidation, a fall back to personal power, even political hysteria if the assessment of the situation is wrong and bad aims are chosen; to a situation that could bring almost all the countries of Europe to the brink of disaster, and only those countries that could recall democratic political culture and education will be able to keep up with the rise of democratic crowd emotion. A comparative European research into the ways and means of processing collective traumas is not only an area that might shed new light on political phenomena, but a requirement of democratic functioning.
Psychometric Properties of the Social Physique Anxiety Scale (SPAS–7) in Spanish Adolescents
Authors: Sáenz-Alvarez Piedad , Sicilia Álvaro , González-Cutre David , Ferriz Roberto
Published: November 2013

The purpose of this study was to validate the Spanish version of Motl and Conroy’s model of the Social Physique Anxiety Scale (SPAS–7). To achieve this goal, a sample of 398 secondary school students was used, and the psychometric properties of the SPAS–7 were examined through different analyses. The results supported the seven-item model, although the item 5 did not show any significant correlation with two items from this model and had a lower factor loading than the rest of items. The structure of the model was invariant across gender and Body Mass Index (BMI). Alpha value over .70 and suitable levels of temporal stability were obtained. Girls and students classified according to the BMI as overweight and obese had higher scores in social physique anxiety than boys and the group classified as underweight and normal range. The findings of this study provided reliability and validity for the SPAS–7 in a Spanish adolescent sample.
Structural and molecular basis of ZNRF3/RNF43 transmembrane ubiquitin ligase inhibition by the Wnt agonist R-spondin
Authors: Zebisch Matthias , Xu Yang , Krastev Christos , MacDonald Bryan T. , Chen Maorong , Gilbert Robert J. C. , He Xi , Jones E. Yvonne
Published: November 2013

The four R-spondin (Rspo) proteins are secreted agonists of Wnt signalling in vertebrates, functioning in embryogenesis and adult stem cell biology. Through ubiquitination and degradation of Wnt receptors, the transmembrane E3 ubiquitin ligase ZNRF3 and related RNF43 antagonize Wnt signalling. Rspo ligands have been reported to inhibit the ligase activity through direct interaction with ZNRF3 and RNF43. Here we report multiple crystal structures of the ZNRF3 ectodomain (ZNRF3ecto), a signalling-competent Furin1–Furin2 (Fu1–Fu2) fragment of Rspo2 (Rspo2Fu1–Fu2), and Rspo2Fu1–Fu2 in complex with ZNRF3ecto, or RNF43ecto. A prominent loop in Fu1 clamps into equivalent grooves in the ZNRF3ecto and RNF43ecto surface. Rspo binding enhances dimerization of ZNRF3ecto but not of RNF43ecto. Comparison of the four Rspo proteins, mutants and chimeras in biophysical and cellular assays shows that their signalling potency depends on their ability to recruit ZNRF3 or RNF43 via Fu1 into a complex with LGR receptors, which interact with Rspo via Fu2.
Event triggered robust filter design for discrete‐time systems
Authors: Meng Xiangyu , Chen Tongwen
Published: November 2013

This study introduces a general event triggered framework of state estimation for discrete‐time systems with parameter uncertainties residing in a polytope. A robust filter is designed to ensure the ℓ2 stability from disturbance to the estimation error and to minimise the ℓ2 gain subject to both packet rate and size constraints. The number of data transmission and the data size are reduced by the utilisation of an event detector and a logarithmic quantiser, respectively. The event detector compares the current output measurement with the last transmitted measurement: if the difference is beyond a prescribed percentage of the current measurement, then the current measurement is transmitted to the quantiser. The quantiser encodes the measurement before sending to the filter via a digital communication channel. Conditions for filter design are found using polynomially parameter‐dependent Lyapunov functions, which generalise the results using quadratic and linearly parameter‐dependent Lyapunov functions. The usefulness of the techniques is demonstrated with an illustrative example.
Molecular electrostatic potentials by systematic molecular fragmentation
Authors: Reid David M. , Collins Michael A.
Published: November 2013

A simple method is presented for estimating the molecular electrostatic potential in and around molecules using systematic molecular fragmentation. This approach estimates the potential directly from the electron density. The accuracy of the method is established for a set of organic molecules and ions. The utility of the approach is demonstrated by estimating the binding energy of a water molecule in an internal cavity in the protein ubiquitin.
Phase transition enhanced thermoelectric figure-of-merit in copper chalcogenides
Authors: Brown David R. , Day Tristan , Borup Kasper A. , Christensen Sebastian , Iversen Bo B. , Snyder G. Jeffrey
Published: November 2013

While thermoelectric materials can be used for solid state cooling, waste heat recovery, and solar electricity generation, low values of the thermoelectric figure of merit, zT, have led to an efficiency too low for widespread use. Thermoelectric effects are characterized by the Seebeck coefficient or thermopower, which is related to the entropy associated with charge transport. For example, coupling spin entropy with the presence of charge carriers has enabled the enhancement of zT in cobalt oxides. We demonstrate that the coupling of a continuous phase transition to carrier transport in Cu2Se over a broad (360–410 K) temperature range results in a dramatic peak in thermopower, an increase in phonon and electron scattering, and a corresponding doubling of zT (to 0.7 at 406 K), and a similar but larger increase over a wider temperature range in the zT of Cu1.97Ag.03Se (almost 1.0 at 400 K). The use of structural entropy for enhanced thermopower could lead to new engineering approaches for thermoelectric materials with high zT and new green applications for thermoelectrics.
Heat kernel asymptotics for magnetic Schrödinger operators
Authors: Bolte Jens , Keppeler Stefan
Published: November 2013

We explicitly construct parametrices for magnetic Schrödinger operators on \documentclass[12pt]{minimal}\begin{document}${\mathbb {R}}^d$\end{document}Rd and prove that they provide a complete small-t expansion for the corresponding heat kernel, both on and off the diagonal.
A new post-quantization constrained propagator for rigid tops for use in path integral quantum simulations
Authors: Guillon Grégoire , Zeng Tao , Roy Pierre-Nicholas
Published: November 2013

In this paper, we extend the previously introduced Post-Quantization Constraints (PQC) procedure [G. Guillon, T. Zeng, and P.-N. Roy, J. Chem. Phys. 138, 184101 (2013)] to construct approximate propagators and energy estimators for different rigid body systems, namely, the spherical, symmetric, and asymmetric tops. These propagators are for use in Path Integral simulations. A thorough discussion of the underlying geometrical concepts is given. Furthermore, a detailed analysis of the convergence properties of the density as well as the energy estimators towards their exact counterparts is presented along with illustrative numerical examples. The Post-Quantization Constraints approach can yield converged results and is a practical alternative to so-called sum over states techniques, where one has to expand the propagator as a sum over a complete set of rotational stationary states [as in E. G. Noya, C. Vega, and C. McBride, J. Chem. Phys. 134, 054117 (2011)] because of its modest memory requirements.
High resolution autofocus for spatial temporal biomedical research
Authors: Li Sihong , Cui Xiaodong , Huang Wei
Published: November 2013

Maintaining focus has been a critical but challenging issue in optical microscopy, particularly for microscopic imaging systems currently used in biomedical research. During live cell imaging, environmental temperature fluctuations and other factors contribute to the unavoidable focus drift. For single molecular imaging and super resolution, focus drift can be significant even over short durations. The current commercial and experimental solutions are either optically complicated, expensive, or with limited axial resolution. Here, we present a simple autofocus solution based on low cost solid state laser and imaging sensor. By improving the optical train design and using real-time data analysis, improvement in axial resolution by approximately two orders of magnitudes over the focal depth of microscope objectives can be achieved. This solution has been tested for prolonged live cell imaging for fast ramping up in environmental chamber temperature and large daily swing in room temperature. In addition, this system can be used to spatial-temporally measure the surface for three-dimensional cell culture and tissue engineering, with flexibility that exceeds commercially available systems.
A high-stability scanning tunneling microscope achieved by an isolated tiny scanner with low voltage imaging capability
Authors: Wang Qi , Hou Yubin , Wang Junting , Lu Qingyou
Published: November 2013

We present a novel homebuilt scanning tunneling microscope (STM) with high quality atomic resolution. It is equipped with a small but powerful GeckoDrive piezoelectric motor which drives a miniature and detachable scanning part to implement coarse approach. The scanning part is a tiny piezoelectric tube scanner (industry type: PZT-8, whose d31 coefficient is one of the lowest) housed in a slightly bigger polished sapphire tube, which is riding on and spring clamped against the knife edges of a tungsten slot. The STM so constructed shows low back-lashing and drifting and high repeatability and immunity to external vibrations. These are confirmed by its low imaging voltages, low distortions in the spiral scanned images, and high atomic resolution quality even when the STM is placed on the ground of the fifth floor without any external or internal vibration isolation devices.
Conduction mechanisms in thin atomic layer deposited Al2O3 layers
Authors: Spahr Holger , Montzka Sebastian , Reinker Johannes , Hirschberg Felix , Kowalsky Wolfgang , Johannes Hans-Hermann
Published: November 2013

Thin Al2O3 layers of 2–135 nm thickness deposited by thermal atomic layer deposition at 80 °C were characterized regarding the current limiting mechanisms by increasing voltage ramp stress. By analyzing the j(U)-characteristics regarding ohmic injection, space charge limited current (SCLC), Schottky-emission, Fowler-Nordheim-tunneling, and Poole-Frenkel-emission, the limiting mechanisms were identified. This was performed by rearranging and plotting the data in a linear scale, such as Schottky-plot, Poole-Frenkel-plot, and Fowler-Nordheim-plot. Linear regression then was applied to the data to extract the values of relative permittivity from Schottky-plot slope and Poole-Frenkel-plot slope. From Fowler-Nordheim-plot slope, the Fowler-Nordheim-energy-barrier was extracted. Example measurements in addition to a statistical overview of the results of all investigated samples are provided. Linear regression was applied to the region of the data that matches the realistic values most. It is concluded that ohmic injection and therefore SCLC only occurs at thicknesses below 12 nm and that the Poole-Frenkel-effect is no significant current limiting process. The extracted Fowler-Nordheim-barriers vary in the range of up to approximately 4 eV but do not show a specific trend. It is discussed whether the negative slope in the Fowler-Nordheim-plot could in some cases be a misinterpreted trap filled limit in the case of space charge limited current.
Sputtering of Si, SiC, InAs, InP, Ge, GaAs, GaSb, and GaN by electrosprayed nanodroplets
Authors: Borrajo-Pelaez Rafael , Grustan-Gutierrez Enric , Gamero-Castaño Manuel
Published: November 2013

This article presents a characterization of the damage caused by energetic beams of electrosprayed nanodroplets striking the surfaces of single-crystal semiconductors including Si, SiC, InAs, InP, Ge, GaAs, GaSb, and GaN. The sputtering yield (number of atoms ejected per projectile's molecule), sputtering rate, and surface roughness are measured as functions of the beam acceleration potential. The maximum values of the sputtering yields range between 1.9 and 2.2 for the technological important but difficult to etch SiC and GaN respectively, and 4.5 for Ge. The maximum sputtering rates for the non-optimized beam flux conditions used in our experiments vary between 409 nm/min for SiC and 2381 nm/min for GaSb. The maximum sputtering rate for GaN is 630 nm/min. Surface roughness increases modestly with acceleration voltage, staying within 2 nm and 20 nm for all beamlet acceleration potentials and materials except Si. At intermediate acceleration potentials, the surface of Si is formed by craters orders of magnitude larger than the projectiles, yielding surface roughness in excess of 60 nm. The effect of projectile dose is studied in the case of Si. This parameter is correlated with the formation of the large craters typical of Si, which suggests that the accumulation of damage following consecutive impacts plays an important role in the interaction between beamlet and target.
High temperature impact response of 998 alumina
Authors: Zaretsky E. B.
Published: November 2013

The dynamic compressive strength (amplitude of the elastic precursor wave) of alumina of 99.8% purity has been studied in a series of planar impact experiments with the 0.25 to 3-mm thick alumina samples, preheated to 1300 K. The dependence of the dynamic tensile (spall) strength of alumina on the ultimate compressive strength was studied with 2-mm thick samples at 300 and 1300 K. The compressive strength of alumina was found to decline by some 30%-35% between 300 and 1300 K, while the absolute values of the spall strength and its dependence on the peak stress were found to stay almost unchanged between 300 and 1300 K. Over the studied temperature interval, the elastic precursor waves in alumina decayed with propagation distance with the decay parameters almost independent of temperature. The availability of decay parameters made it possible to determine the strain rate function τ(γ̇,T) of alumina and to derive some conclusions regarding the onset of inelastic deformation in this ceramic.
Atom probe tomography evaporation behavior of C-axis GaN nanowires: Crystallographic, stoichiometric, and detection efficiency aspects
Authors: Diercks David R. , Gorman Brian P. , Kirchhofer Rita , Sanford Norman , Bertness Kris , Brubaker Matt
Published: November 2013

The field evaporation behavior of c-axis GaN nanowires was explored in two different laser-pulsed atom probe tomography (APT) instruments. Transmission electron microscopy imaging before and after atom probe tomography analysis was used to assist in reconstructing the data and assess the observed evaporation behavior. It was found that the ionic species exhibited preferential locations for evaporation related to the underlying crystal structure of the GaN and that the species which evaporated from these locations was dependent on the pulsed laser energy. Additionally, the overall stoichiometry measured by APT was significantly correlated with the energy of the laser pulses. At the lowest laser energies, the apparent composition was nitrogen-rich, while higher laser energies resulted in measurements of predominantly gallium compositions. The percent of ions detected (detection efficiency) for these specimens was found to be considerably below that shown for other materials, even for laser energies which produced the expected Ga:N ratio. The apparent stoichiometry variation and low detection efficiency appear to be a result of evaporation of Ga ions between laser pulses at the lowest laser energies and evaporation of neutral N2 species at higher laser energies. All of these behaviors are tied to the formation of nitrogen-nitrogen bonds on the tip surface, which occurred under all analysis conditions. Similar field evaporation behaviors are therefore expected for other materials where the anionic species readily form a strong diatomic bond.
Ultra-high throughput detection of single cell β-galactosidase activity in droplets using micro-optical lens array
Authors: Lim Jiseok , Vrignon Jérémy , Gruner Philipp , Karamitros Christos S. , Konrad Manfred , Baret Jean-Christophe
Published: November 2013

We demonstrate the use of a hybrid microfluidic-micro-optical system for the screening of enzymatic activity at the single cell level. Escherichia coli β-galactosidase activity is revealed by a fluorogenic assay in 100 pl droplets. Individual droplets containing cells are screened by measuring their fluorescence signal using a high-speed camera. The measurement is parallelized over 100 channels equipped with microlenses and analyzed by image processing. A reinjection rate of 1 ml of emulsion per minute was reached corresponding to more than 105 droplets per second, an analytical throughput larger than those obtained using flow cytometry.
Voltage-controlled ferromagnetism and magnetoresistance in LaCoO3/SrTiO3 heterostructures
Authors: Hu Chengqing , Park Keun Woo , Posadas Agham , Jordan-Sweet Jean L. , Demkov Alexander A. , Yu Edward T.
Published: November 2013

A LaCoO3/SrTiO3 heterostructure grown on Si (001) is shown to provide electrically switchable ferromagnetism, a large, electrically tunable magnetoresistance, and a vehicle for achieving and probing electrical control over ferromagnetic behavior at submicron dimensions. Fabrication of devices in a field-effect transistor geometry enables application of a gate bias voltage that modulates strain in the heterostructure via the converse piezoelectric effect in SrTiO3, leading to an artificial inverse magnetoelectric effect arising from the dependence of ferromagnetism in the LaCoO3 layer on strain. Below the Curie temperature of the LaCoO3 layer, this effect leads to modulation of resistance in LaCoO3 as large as 100%, and magnetoresistance as high as 80%, both of which arise from carrier scattering at ferromagnetic-nonmagnetic interfaces in LaCoO3. Finite-element numerical modeling of electric field distributions is used to explain the dependence of carrier transport behavior on gate contact geometry, and a Valet-Fert transport model enables determination of spin polarization in the LaCoO3 layer. Piezoresponse force microscopy is used to confirm the existence of piezoelectric response in SrTiO3 grown on Si (001). It is also shown that this structure offers the possibility of achieving exclusive-NOR logic functionality within a single device.
Estimation of forest structure and canopy fuel parameters from small-footprint full-waveform LiDAR data
Authors: Hermosilla Txomin , Ruiz Luis A. , Kazakova Alexandra N. , Coops Nicholas C. , Moskal L. Monika
Published: November 2013

Precise knowledge of fuel conditions is important for predicting fire hazards and simulating fire growth and intensity across the landscape. We present a methodology to retrieve and map forest canopy fuel and other forest structural parameters using small-footprint full-waveform airborne light detection and ranging (LiDAR) data. Full-waveform LiDAR sensors register the complete returned backscattered signal through time and can describe physical properties of the intercepted objects. This study was undertaken in a mixed forest dominated by Douglas-fir, occasionally mixed with other conifers, in north-west Oregon (United States). We extracted two sets of LiDAR metrics using pulse detection and waveform modelling and then constructed several predictive models using forward stepwise multiple linear regression. The resulting models explained ~80% of the variability for many of the canopy fuel and forest structure parameters: aboveground biomass (R2=0.84), quadratic mean diameter (R2=0.82), canopy height (R2=0.79), canopy base height (R2=0.78) and canopy fuel load (R2=0.79). The lowest performing models included basal area (R2=0.76), stand volume (R2=0.73), canopy bulk density (R2=0.67) and stand density index (R2=0.66). Our results indicate that full-waveform LiDAR systems show promise in systematically characterising the structure and canopy fuel loads of forests, which may enable accurate fire behaviour forecasting that in turn supports the development of prevention and planning policies.
Fine-scale variation in meiotic recombination in
Mimulus
inferred from population shotgun sequencing
Authors: Hellsten Uffe , Wright Kevin M. , Jenkins Jerry , Shu Shengqiang , Yuan Yaowu , Wessler Susan R. , Schmutz Jeremy , Willis John H. , Rokhsar Daniel S.
Published: November 2013

Significance

This work characterizes variation in recombination across the genome of a flowering plant in detail using unique population genomic and computational approaches. The resulting recombination map approaches nucleotide-level resolution and advances our understanding of basic properties of recombination, notably the findings of enhanced recombination near starts of genes, varying degrees of intensities of “hotspots,” higher activity in exons than introns, and that a large fraction of the genome appears devoid of any recombination activity.
ESCRT regulates surface expression of the Kir2.1 potassium channel
Authors: Kolb Alexander R. , Needham Patrick G. , Rothenberg Cari , Guerriero Christopher J. , Welling Paul A. , Brodsky Jeffrey L.
Published: November 2013

Protein quality control (PQC) is required to ensure cellular health. PQC is recognized for targeting the destruction of defective polypeptides, whereas regulated protein degradation mechanisms modulate the concentration of specific proteins in concert with physiological demands. For example, ion channel levels are physiologically regulated within tight limits, but a system-wide approach to define which degradative systems are involved is lacking. We focus on the Kir2.1 potassium channel because altered Kir2.1 levels lead to human disease and Kir2.1 restores growth on low-potassium medium in yeast mutated for endogenous potassium channels. Using this system, first we find that Kir2.1 is targeted for endoplasmic reticulum–associated degradation (ERAD). Next a synthetic gene array identifies nonessential genes that negatively regulate Kir2.1. The most prominent gene family that emerges from this effort encodes members of endosomal sorting complex required for transport (ESCRT). ERAD and ESCRT also mediate Kir2.1 degradation in human cells, with ESCRT playing a more prominent role. Thus multiple proteolytic pathways control Kir2.1 levels at the plasma membrane.
Age and growth parameters for three heavily exploited shark species off temperate eastern Australia
Authors: Geraghty Pascal T. , Macbeth William G. , Harry Alastair V. , Bell Jacqueline E. , Yerman Michelle N. , Williamson Jane E.
Published: November 2013

The removal of large predatory sharks from the world's oceans poses profound threats to marine community structure and species conservation. Effective management of exploited shark stocks requires a sound understanding of the life histories of target species. Here we provide the first assessment of age and growth for Carcharhinus brevipinna in Australian waters, and for C. obscurus and C. plumbeus in eastern Australian waters, based on interpretations of vertebral growth bands. In doing so, we provide arguably among the most robust growth parameters to date for the abovementioned taxa on the bases of genetic validation and sample size and distribution, but acknowledge equally a range of limitations—most notably those associated with vertebral ageing and our lack of age validation. Comparatively, the three species displayed both contrasts and consistencies in their growth characteristics off Australia's southeast coast. For all three sharks, rates of growth were greatest in the years immediately after birth, males grew more rapidly than females in the juvenile phase, and females were observed to grow larger, live longer and were generally larger at any given age. Longevity and all modelled growth parameters (L∞, k and L0), however, differed among the three species, and appeared to challenge the findings for conspecific populations in other parts of the world. The validity of these latter comparisons is, however, compromised by a range of confounding factors. Nevertheless, we provide the least conservative k estimates for C. obscurus and C. plumbeus of those previously reported, and extend maximum age estimates for C. brevipinna. In this way, our results have important implications for the assessment of natural mortality, productivity, and hence resilience to stock depletion, in these species in southeastern Australian waters.
Twentieth century Atlantic meridional overturning circulation as an indicator of global ocean multidecadal variability: influences on sea level anomalies and small pelagic fishery synchronies
Authors: Kamykowski Daniel
Published: November 2013

The Atlantic dipole phosphate utilization (ADPU) index, derived through statistical conversion of 20th century Atlantic basin subpolar sea surface temperatures, is used as a fingerprint of Atlantic meridional overturning circulation (AMOC) variability and as an indicator of global Meridional Overturing Circulation (MOC) variability. ADPU index correlations with differences in sea level anomalies (SLAs) between Canada and the UK and across the Isthmus of Panama demonstrate intrabasin and interbasin associations with MOC variability. Cross-correlation analyses of ADPU index, SLAs, and sardine (S) and anchovy (A) catch differences [S −A] (normalized sardine catch minus normalized anchovy catch) confirm strong correlations between ADPU and [S −A] off Japan, California, Peru and Southwest Africa (Benguela). Statistically significant cross correlations also exist between the ADPU index and SLAs for Japan, California, Peru and Benguela, and for SLAs and [S − A] for Japan, California and Peru, but the short time-series lengths compared with the length of the multidecadal cycle limit the interpretation of the observed lead-lags. Though correlation is not causality, the correlation analyses developed here are useful in support of hypothesis generation. The proposed hypothesis to explain the observed small pelagic fishery synchronies asserts: (i) ocean bathymetry and continental distributions interact with multidecadal variations in MOC strength that occur along the conceptual global conveyor belt to generate changes in global oceanic planetary waves and mesoscale eddies that propagate through the world ocean; (ii) each small pelagic fishery region has a unique spatial relationship with pertinent oceanic planetary wave and mesoscale eddy source regions that affect the timing and strength of the waves and eddies that influence the nearby boundary current; (iii) synchronous changes or phasing among global fisheries depend on how and when MOC variability mediated by oceanic planetary waves and mesoscale eddies reaches each fishery region; (iv) oceanic planetary waves and/or mesoscale eddies influence the strength or meandering of the boundary current adjacent to a small pelagic fishery region to change local SLAs and environmental conditions to favour sardine or anchovy populations at different times.
Polymer crystallization studies under processing-relevant conditions at the SAXS/WAXS DUBBLE beamline at the ESRF
Authors: Portale Giuseppe , Cavallo Dario , Alfonso Giovanni Carlo , Hermida-Merino Daniel , van Drongelen Martin , Balzano Luigi , Peters G. W. M. , Goossens J. G. P. , Bras Wim
Published: November 2013

Recent developments on the experimental infrastructure and the acquisition of new detectors on the Dutch–Belgian beamline BM26B at the ESRF offer novel and promising possibilities for synchrotron X-ray experiments in the field of polymer crystallization under processing-relevant conditions. In this contribution, some of the most recent experiments mimicking conditions similar to those relevant for the plastics processing industry are discussed. Simultaneous thermal analysis and wide-angle X-ray scattering (WAXS) experiments, at the millisecond time-frame level, on β-nucleated isotactic polypropylene (i-PP) samples subjected to ballistic cooling up to 230 K s−1, show that the efficiency of the nucleating agent can be suppressed when quenched cooling rates higher than 130 K s−1are used.In situWAXS experiments using small-scale industrial equipment during a real film blowing process reveal the dependence of the onset of crystallinity (the so-called freeze line) and the crystal orientation as a function of different take-up and blow-up ratios.In situsmall-angle X-ray scattering (SAXS) experiments during high-flow fields reveal the formation of shish and kebab structures in i-PP as a function of the imposed stress. Quantitative analysis of i-PP flow-induced structures is presented. The beamline specifications required to obtain high quality and industrially relevant results are also briefly reported.
Fast pole figure acquisition using area detectors at the DiffAbs beamline – Synchrotron SOLEIL
Authors: Mocuta Cristian , Richard Marie-Ingrid , Fouet Julie , Stanescu Stefan , Barbier Antoine , Guichet Christophe , Thomas Olivier , Hustache Stéphanie , Zozulya Alexey V. , Thiaudière Dominique
Published: November 2013

Structural anisotropy, for example texture, may govern important physical properties of thin film, such as electrical, magnetic and/or mechanical ones. Texture (orientation information) is typically observed and quantified by the measurement of so-called pole figures. An optimized experimental approach implemented at the DiffAbs beamline (Synchrotron SOLEIL) is presented here. Using an X-ray pixel area detector and synchrotron radiation sources, a complete pole figure (with resolutions adapted for metallic textured thin films, typically of the order of a few degrees) can be measured in time intervals as short as one minute. The necessary corrections enabling complete pole figure retrieval from the experimental data using this optimized approach are provided and discussed. A gain in measuring time by up to two orders of magnitude is found with respect to the use of a point detector (classical approach) under the same experimental conditions. Data measured using these two approaches are shown, compared and discussed.
Symmetry groups of Moroccan geometric woodwork patterns
Authors: Aboufadil Youssef , Thalal Abdelmalek , Raghni My Ahmed El Idrissi
Published: November 2013

Many works report the classification and analysis of geometric patterns, particularly those found in the Alhambra, Spain, but few authors have been interested in Moroccan motifs, especially those made on wood. Studies and analyses made on nearly a thousand Moroccan patterns constructed on wood and belonging to different periods between the 14th and 19th centuries show that, despite their great diversity, only five plane groups are present. Groupsp4mmandc2mmare predominant,p6mmandp2mmare less frequent, whilep4gmis rare. In this work, it is shown that it is possible to obtain the 17 plane symmetry groups by using a master craftsmen's method calledHasba. The set of patterns are generated fromn-fold rosettes, considered as the basic motif, by theHasbamethod. The combination and the overlap between these basic elements generate other basic elements. By repeating these basic elements, it is possible to construct patterns having various symmetry groups. In this article, only uncoloured patterns are considered and the interlace patterns are disregarded.