bluuebunny/crossref_metadata_2025 huggingface dataset:
Linguistique et école primaire: en quoi l'approche diglossique est-elle la meilleure façon d'apprendre le français ‘académique’?
Authors: BARRA-JOVER MARIO
Published: January 2013

L'enseignement du français académique à l'école primaire est fondé sur un préjugé injustifié: l'élève de CP arriverait à l'école avec une forme précaire de parler qui n'est identifiable que par référence à son écart vis-à-vis de la forme académique écrite qui est l'objectif à atteindre. Autrement dit, on n'accorde pas au dispositif langagier qu'il a acquis naturellement le statut de ‘grammaire’ et on confond les traits émanant du processus naturel d'apprentissage, encore incomplet, avec les traits propres au français spontanée et qui persistent chez les adultes qui ont, par ailleurs, été la source de stimuli pour l'enfant. À ceci s'ajoute une deuxième confusion: l'apprentissage de la seule ‘vraie’ grammaire et l'apprentissage de l'écrit n'en font qu'un, puisque l'oral n'est qu'un reflet appauvri de l'écrit. Ainsi, par exemple, l'enfant devra ‘juste’ apprendre à écrire l'accord en genre, sans pour autant avoir reçu assez de stimuli pour intégrer dans sa grammaire naturelle le fonctionnement de l'accord.

Dans cet article est proposé un programme qui, partant de l'hypothèse diglossique, cherche à établir une autre approche de l'apprentissage. La clé de cette approche est la bonne compréhension de la grammaire ‘de départ’ de l'enfant en tant qu'objet cohérent, de façon à faire la différence entre: a) les ‘anomalies’ qui vont évoluer spontanément dans le processus d'acquisition de la grammaire adulte indépendamment de l'apprentissage de la grammaire académique (par exemple, les formes analogiques comme le gent ou ouvri) ; b) les ‘anomalies’ par rapport à la grammaire académique qui vont persister dans la grammaire adulte (par exemple, les interrogatives comme c'est quoi ton problème ?) et qui ne doivent pas d'être stigmatisées mais placées dans un contexte d'interaction spécifique bien expliqué ; c) les traits de la grammaire académique qui ne pourront pas être intégrés dans la grammaire adulte de façon naturelle ou par simple pénalisation mais moyennant l'explicitation de règles et dont l'ignorance empêche l'accès actif à la grammaire académique (par exemple, l'accord en genre et nombre ou le sujet lexical sans dédoublement pronominal ; d) les traits de la grammaire académique soutenue qui ne peuvent pas être acquis sans un entraînement à un niveau supérieur et qui ne sont pas décisifs pour avoir un accès actif à cette grammaire (par exemple, le passé simple, la plupart des interrogatives à inversion et, surtout, l'imparfait de subjonctif).

Seulement une bonne conscience de l'existence de ces classes permettra de bâtir des programmes ciblant les aspects sur lesquels l'enseignant doit intervenir normativement ainsi que les stratégies pour le faire. C'est ainsi que le français académique sera perçu (et apprécie) comme une deuxième grammaire essentielle pour l'insertion sociale et non pas comme le vrai français.
On the Independence Number of Steiner Systems
Authors: EUSTIS ALEX , VERSTRAËTE JACQUES
Published: January 2013

Apartial Steiner (n,r,l)-systemis anr-uniform hypergraph onnvertices in which every set oflvertices is contained in at most one edge. A partial Steiner (n,r,l)-system iscompleteif every set oflvertices is contained in exactly one edge. In a hypergraph, the independence number α() denotes the maximum size of a set of vertices incontaining no edge. In this article we prove the following. Given integersr,lsuch thatr≥ 2l− 1 ≥ 3, we prove that there exists a partial Steiner (n,r,l)-systemsuch that$$\alpha(\HH) \lesssim \biggl(\frac{l-1}{r-1}(r)_l\biggr)^{\frac{1}{r-1}}n^{\frac{r-l}{r-1}} (\log n)^{\frac{1}{r-1}} \quad \mbox{ as }n \rightarrow \infty.$$This improves earlier results of Phelps and Rödl, and Rödl and Ŝinajová. We conjecture that it is best possible as it matches the independence number of a randomr-uniform hypergraph of the same density. Ifl= 2 orl= 3, then for infinitely manyrthe partial Steiner systems constructed are complete for infinitely manyn.
Effect of nutrition education intervention based on Pender's Health Promotion Model in improving the frequency and nutrient intake of breakfast consumption among female Iranian students
Authors: Dehdari Tahereh , Rahimi Tahereh , Aryaeian Naheed , Gohari Mahmood Reza
Published: January 2013

Objective

To determine the effectiveness of nutrition education intervention based on Pender's Health Promotion Model in improving the frequency and nutrient intake of breakfast consumption among female Iranian students.

Design

The quasi-experimental study based on Pender's Health Promotion Model was conducted during April–June 2011. Information (data) was collected by self-administered questionnaire. In addition, a 3 d breakfast record was analysed. P < 0·05 was considered significant.

Setting

Two middle schools in average-income areas of Qom, Iran.

Subjects

One hundred female middle-school students.

Results

There was a significant reduction in immediate competing demands and preferences, perceived barriers and negative activity-related affect constructs in the experimental group after education compared with the control group. In addition, perceived benefit, perceived self-efficacy, positive activity-related affect, interpersonal influences, situational influences, commitment to a plan of action, frequency and intakes of macronutrients and most micronutrients of breakfast consumption were also significantly higher in the experimental group compared with the control group after the nutrition education intervention.

Conclusions

Constructs of Pender's Health Promotion Model provide a suitable source for designing strategies and content of a nutrition education intervention for improving the frequency and nutrient intake of breakfast consumption among female students.
Role of state-dependent learning in the cognitive effects of caffeine in mice
Authors: Sanday Leandro , Zanin Karina A. , Patti Camilla L. , Fernandes-Santos Luciano , Oliveira Larissa C. , Longo Beatriz M. , Andersen Monica L. , Tufik Sergio , Frussa-Filho Roberto
Published: January 2013

Caffeine is the most widely used psychoactive substance in the world and it is generally believed that it promotes beneficial effects on cognitive performance. However, there is also evidence suggesting that caffeine has inhibitory effects on learning and memory. Considering that caffeine may have anxiogenic effects, thus changing the emotional state of the subjects, state-dependent learning may play a role in caffeine-induced cognitive alterations. Mice were administered 20 mg/kg caffeine before training and/or before testing both in the plus-maze discriminative avoidance task (an animal model that concomitantly evaluates learning, memory, anxiety-like behaviour and general activity) and in the inhibitory avoidance task, a classic paradigm for evaluating memory in rodents. Pre-training caffeine administration did not modify learning, but produced an anxiogenic effect and impaired memory retention. While pre-test administration of caffeine did not modify retrieval on its own, the pre-test administration counteracted the memory deficit induced by the pre-training caffeine injection in both the plus-maze discriminative and inhibitory avoidance tasks. Our data demonstrate that caffeine-induced memory deficits are critically related to state-dependent learning, reinforcing the importance of considering the participation of state-dependency on the interpretation of the cognitive effects of caffeine. The possible participation of caffeine-induced anxiety alterations in state-dependent memory deficits is discussed.
Review of Antarctic astronomy
Authors: Storey John W. V.
Published: January 2013

Astronomers have always sought the best sites for their telescopes. Antarctica, with its high plateau reaching to above 4,000 metres, intense cold, exceptionally low humidity and stable atmosphere, offers what for many forms of astronomy is the ultimate observing location on this planet. While optical, infrared and millimetre astronomers are building their observatories on the ice, particle physicists are using the ice itself as a detector and exploration of the terahertz region is being conducted from circumpolar long-duration balloons. Remarkable astronomical discoveries are already coming out of Antarctica, and much, much more is just around the corner.
Autonomous observatories for the Antarctic plateau
Authors: Lawrence J. S. , Ashley M. C. B. , Storey J. W. V.
Published: January 2013

Antarctic astronomical site-testing has been conducted using autonomous self-powered observatories for more than a decade (the AASTO at South Pole, the AASTINO at Dome C, and PLATO at Dome A/Dome F). More recently autonomous (PLATO) observatories have been developed and deployed to support small-scale scientific instruments, such as HEAT, a 0.6 m aperture terahertz telescope at Ridge A, and AST3, a 0.5 m optical telescope array at Dome A. This paper reviews the evolution of autonomous Antarctic astronomical observatories, and discusses the requirements and implications for observatories that will be needed for future larger-scale facilities.
First look at HRCAM images from Dome A, Antarctica
Authors: Sims Geoff , Ashley Michael C. B. , Cui Xiangqun , Feng Long Long , Gong Xuefei , Hu Zhongwen , Lawrence Jon S. , Luong-Van Daniel M. , Shang Zhaohui , Storey John W. V. , Tothill Nick , Wang Lifan , Yang Huigen , Yang Ji , Zhou Xu , Zhu Zhenxi
Published: January 2013

HRCAM (High Resolution CAMera) is a Canon 50D 15-megapixel digital SLR camera equipped with a Sigma 4.5 mm f/2.8 fish-eye lens. It was installed at Dome A on the Antarctic plateau in January 2010 and photographs the sky every 15 minutes. Primarily functioning as a site-testing instrument, data obtained from HRCAM provide valuable statistics on cloud cover, sky transparency and the distribution and frequency of auroral activity. We present a first look at data from HRCAM during 2010, including an overview of how we intend to reduce the images. We also demonstrate the potential of stellar photometry by using linear combinations of the in-built Canon RGB filters to convert instrumental magnitudes into the photometric BVR bands.
The Path from AMANDA to IceCube
Authors: Karle Albrecht
Published: January 2013

In May 2011, IceCube, a neutrino telescope with one cubic kilometer instrumented volume started full operation with 5,160 sensors. The plan to build an experiment of this scale was based in part on the successful realization of a prototype experiment, the Antarctic Muon and Neutrino Detector Array. Here, we will review some of the major challenges and milestones.
Submillimeter Astronomy from the South Pole (AST/RO)
Authors: Stark Antony A.
Published: January 2013

The Antarctic Submillimeter Telescope and Remote Observatory (AST/RO), a 1.7 m diameter offset Gregorian telescope for astronomy and aeronomy studies at wavelengths between 200 and 2000 μm, saw first light in 1995 and operated until 2005. It was the first radio telescope to operate continuously throughout the winter on the Antarctic Plateau. It served as a site testing instrument and prototype for later instruments, as well as executing a wide variety of scientific programs that resulted in six doctoral theses and more than one hundred scientific publications. The South Pole environment is unique among observatory sites for unusually low wind speeds, low absolute humidity, and the consistent clarity of the submillimeter sky. Especially significant are the exceptionally low values of sky noise found at this site, a result of the small water vapor content of the atmosphere. Multiple submillimeter-wave and Terahertz detector systems were in operation on AST/RO, including heterodyne and bolometric arrays. AST/RO's legacy includes comprehensive submillimeter-wave site testing of the South Pole, spectroscopic studies of 492 GHz and 809 GHz neutral atomic carbon and 460 GHz and 806 GHz carbon monoxide in the Milky Way and Magellanic Clouds, and the first detection of the 1.46 THz [N II] line from a ground-based observatory.
Dome Fuji Station in East Antarctica and the Japanese Antarctic Research Expedition
Authors: Shiraishi Kazuyuki
Published: January 2013

Japanese Antarctic Research Expedition (JARE) commenced on the occasion of International Geophysical Year in 1957–1958. Syowa Station, the primary station for JARE operations, is located along the northeastern coastal region of Lützow-Holm Bay, East Antarctica (69° 00′S, 39° 35′E), and was opened on 29 January 1957. Since then, JARE have been carrying out research in various fields of earth and planetary sciences and life science. Astronomical science, however, has not been popular in Antarctica. In 1995, JARE established a new inland station, Dome Fuji Station (77° 19′S, 39° 42′E), which, at 3,810 m a.s.l., is located on one of major domes of the Antarctic ice sheet, some 1,000 km south of Syowa. The climatic conditions at Dome Fuji are harsh, with an annual average air temperature of −54°C, and a recorded minimum of −79°C. In 2007, JARE completed scientific drilling to obtain ice core samples of the Antarctic ice sheet reaching 3,050 m in depth. These ice cores record environmental conditions of the earth extending back some 720,000 B.P. In recent years, it is widely known that the high-altitude environment of inland Antarctica is suitable for astronomical observations and the Japanese astronomy community identified Dome Fuji Station as a potential candidate for a future astronomical observatory. In this article, the history of Japanese Antarctic activities are described in terms of access to the inland plateau of the Antarctic continent. The general scheme and future plans of science objectives and logistics of JARE will also be introduced.
Dome Fuji in Antarctica as a Site for Infrared and Terahertz Astronomy
Authors: Seta Masumichi , Nakai Naomasa , Ishii Shun , Nagai Makoto , Miyamoto Yusuke , Ichikawa Takashi , Takato Naruhisa , Motoyama Hideaki
Published: January 2013

Dome Fuji on the Antarctic high plateau may be a good site for terahertz astronomy because of its high altitude of 3,810 m and low average temperature of −54°C. We have demonstrated that the opacity at 220 GHz from Dome Fuji in summer is very good and stable; τ = 0.045 ± 0.007. We have developed a transportable 30 cm telescope to map the Milky Way in the CO (J=4–3) and the [CI] (3P1–3P0) lines at Dome Fuji from 2014. It has a 9′ beam. Physical conditions such as density and temperature of molecular clouds could be derived from a direct comparison of CO (J=4–3) and [CI] (3P1–3P0) with CO (J=1–0) taken by the Columbia–CfA survey. We are also developing a 1.2 m sub-millimeter telescope. It will be equipped with a dual superconducting device (SIS) receiver for 500/800 GHz. The 1.2 m telescope produces a 2.2′ beam at 492 GHz and could map a molecular cloud entirely. It could also observe nearby galaxies in the CO (J=4–3), CO (J=7–6), [CI] (3P1–3P0), [CI] (3P2–3P1) and in continuum emission between 460–810 GHz.
Opportunities for Terahertz Facilities on the High Plateau
Authors: Kulesa Craig A. , Ashley Michael C.B. , Augarten Yael , Bonner Colin S. , Burton Michael G. , Bycroft Luke , Lawrence Jon , Lesser David H. , Loomis John , Luong-Van Daniel M. , Martin Christopher L. , McLaren Campbell , Stapleton Shawntel , Storey John W.V. , Swift Brandon J. , Tothill Nicholas F.H. , Walker Christopher K. , Young Abram G.
Published: January 2013

While the summit of the Antarctic Plateau has long been expected to harbor the best ground-based sites for terahertz (THz) frequency astronomical investigations, it is only recently that direct observations of exceptional THz atmospheric transmission and stability have been obtained. These observations, in combination with recent technological advancements in astronomical instrumentation and autonomous field platforms, make the recognition and realization of terahertz observatories on the high plateau feasible and timely. Here, we will explore the context of terahertz astronomy in the era of Herschel, and the crucial role that observatories on the Antarctic Plateau can play. We explore the important scientific questions to which observations from this unique environment may be most productively applied. We examine the importance and complementarity of Antarctic THz astronomy in the light of contemporary facilities such as ALMA, CCAT, SOFIA and (U)LDB ballooning. Finally, building from the roots of THz facilities in Antarctica to present efforts, we broadly highlight future facilities that will exploit the unique advantages of the Polar Plateau and provide a meaningful, lasting astrophysical legacy.
Optical Interferometry from the Antarctic
Authors: Tuthill Peter
Published: January 2013

The unique atmospheric conditions which pertain in the high Antarctic plateau offer dramatic gains for many areas of Astrophysics. Optical Interferometry is among the most technologically demanding branches of modern instrumentation, and furthermore, is one which is most strongly limited by the stability of the atmosphere at the observatory site. The long-term potential for spectacular gains by implementing an interferometer on the high Antarctic plateau are presented.
A Multi-Aperture Scintillation Sensor for Dome A, Antarctica
Authors: Chen Hualin , Pei Chong , Yuan Xiangyan
Published: January 2013

Site-testing measurements by the Australian group has already shown that Dome C on the Antarctic plateau is one of the best ground-based astronomical sites. Furthermore, Dome A, the Antarctic Kunlun Station, as the highest point on Antarctic inland plateau, where a Chinese Antarctic scientific expedition team first reached in 2005, is widely predicted to be an even better astronomical site by the international astronomical community. Preliminary site-testing carried out by the Center for Antarctic Astronomy (CAS) also confirms Dome A as a potential astronomical site. Multi-aperture scintillation sensors (MASS) can measure the seeing and isoplantic angle, the turbulence profile, etc., which are very important site-testing parameters that we urgently need. The MASS site testing at Dome A is presented here, and includes the method of processing data and the hardware for the extreme conditions of Dome A, Antarctica.
The self-perpetuation of EU constitutionalism in the area of free movement of persons: Virtuous or vicious cycle?
Authors: WIESBROCK ANJA
Published: January 2013

This paper analyses the mutual influence and self-perpetuating cycle of legitimacy of EU legal scholars and the Court of Justice of the European Union (CJEU) in expanding and broadening the free movement rights of Union citizens and their family members. It is argued that legal scholars have played a dual role in promoting the constitutional paradigm of an ever-expanding scope of directly enforceable residence and movement rights in the EU. First, by presenting the expansion of free movement rights as an inevitable outcome of the EU constitutional order based on directly enforceable individual rights, scholars have played a significant role in legitimizing the jurisprudence of the Court in the face of initial resistance from the member states. Second, legal scholars have been an important source for the Court of Justice in developing its case law in this area. The Advocates General in their opinions have drawn on an expanding field of scholarship presenting the expansion of free movement rights as an inherent feature of the EU as a constitutional legal order. Spurred by the objective of turning the EU into more than an internal market, the opinions of the Advocates General have mostly been followed by the Court. Legal scholars have thus served not only as a legitimizing force, but also as a source of inspiration for the perceived constitutionalization of free movement rights in the EU.
Psychophysiological Response to Acoustic Intensity Change in a Musical Chord
Authors: Olsen Kirk N. , Stevens Catherine J.
Published: January 2013

This paper investigates psychological and psychophysiological components of arousal and emotional response to a violin chord stimulus comprised of continuous increases (up-ramp) or decreases (down-ramp) of intensity. A factorial experiment manipulated direction of intensity change (60–90 dB SPL up-ramp, 90–60 dB SPL down-ramp) and duration (1.8 s, 3.6 s) within-subjects (N = 45). Dependent variables were ratings of emotional arousal, valence, and loudness change, and a fine-grained analysis of event-related skin conductance response (SCR). As hypothesized, relative to down-ramps, musical up-ramps elicited significantly higher ratings of emotional arousal and loudness change, with marginally longer SCR rise times. However, SCR magnitude was greater in response to musical down-ramps. The implications of acoustic intensity change for music-induced emotion and auditory warning perception are discussed.
Age-Related Changes in Spontaneous Oscillations Assessed by Wavelet Transform of Cerebral Oxygenation and Arterial Blood Pressure Signals
Authors: Li Zengyong , Zhang Ming , Xin Qing , Luo Site , Cui Ruofei , Zhou Weiei , Lu Liqian
Published: January 2013

The study aims to assess the spontaneous oscillations in elderly subjects based on the wavelet transform of cerebral oxygenation (CO) and arterial blood pressure (ABP) signals. Continuous recordings of near-infrared spectroscopy (NIRS) and ABP signals were obtained from simultaneous measurements in 20 young subjects (age: 27.3 ± 7.1 years) and 15 elderly subjects (age: 70.8 ± 5.1 years) at rest. Using spectral analysis based on wavelet transform, five frequency intervals were identified (I, 0.005 to 0.02 Hz; II, 0.02 to 0.06 Hz; III, 0.06 to 0.15 Hz; IV, 0.15 to 0.40 Hz; and V, 0.40 to 2.0 Hz). The average amplitudes of the Δ[HbO2] and tissue oxygenation index in intervals I to V and the relative amplitudes in intervals IV and V were significantly lower in elderly subjects than in young subjects ( P < 0.05). In addition, the relative amplitudes of the ABP in interval I were significantly lower in elderly subjects than in young subjects ( P = 0.016). The present findings suggest the presence of a cerebrovascular degenerative process caused by aging. Spontaneous oscillations in the CO could be used as an indicator of cerebrovascular changes and could be used to identify the risk for cerebrovascular degenerative processes.
Ultrasonographic Markers of Vascular Risk in Patients with Asymptomatic Carotid Stenosis
Authors: Silvestrini Mauro , Altamura Claudia , Cerqua Raffaella , Pasqualetti Patrizio , Viticchi Giovanna , Provinciali Leandro , Paulon Luca , Vernieri Fabrizio
Published: January 2013

Six-hundred twenty-one subjects with unilateral asymptomatic severe internal carotid artery (ICA) stenosis were prospectively evaluated with a median follow-up of 27 months (min = 6, max = 68). Vascular risk profile, plaque characteristic, stenosis progression, and common carotid artery intima-media thickness (IMT) were investigated in all patients. Outcome measures were occurrence of ischemic stroke ipsilateral to ICA stenosis and vascular death, while myocardial infarction, contralateral strokes, and transient ischemic attack were considered as competing events. A total of 99 subjects (15.9%) suffered from a vascular event. Among them, 39 were strokes ipsilateral to the stenosis (6.3%). Degree of stenosis, stenosis progression, and common carotid artery IMT resulted as independent predictive factors of ipsilateral stroke. Considering a stenosis of 60% to 70% as reference, a degree between 71% and 90% increased the risk by 2.45, while a degree between 91% and 99% increased the risk by 3.26. The progression of stenosis was a strong risk factor (hazard ratio = 4.32). Finally, the role of carotid IMT was confirmed as crucial additional measure, with an increased risk by 25% for each 0.1 mm IMT increase. Our data suggest that IMT, stenosis progression and severity should be considered as risk factors for cerebrovascular events in asymptomatic subjects with severe ICA stenosis.
Phosphorylation regulates TRPV1 association with β-arrestin-2
Authors: Por Elaine D. , Gomez Ruben , Akopian Armen N. , Jeske Nathaniel A.
Published: January 2013

Post-translational modifications in TRPV1 (transient receptor potential vanilloid 1) play a critical role in channel activity. Phosphorylation of serine/threonine residues within the N- and C-termini of TRPV1 are implicated in receptor sensitization and activation. Conversely, TRPV1 desensitization occurs via a calcium-dependent mechanism and leads to receptor de-phosphorylation. Importantly, we recently demonstrated that TRPV1 association with β-arrestin-2 is critical to receptor desensitization via its ability to scaffold the phosphodiesterase PDE4D5 to the receptor, regulating TRPV1 phosphorylation. In the present study, we demonstrate that phosphorylation of TRPV1 and β-arrestin-2 regulates this association at the membrane. Under serum-free media conditions, we observed a significant decrease in TRPV1 and β-arrestin-2 association in transfected CHO (Chinese-hamster ovary) cells. Pharmacological activation of the kinases PKA (protein kinase A) and PKC (protein kinase C) led to a robust increase in TRPV1 and β-arrestin-2 association, whereas inhibition of PKA and PKC decreased association. Previously, we identified potential PKA residues (Ser116, Thr370) in the N-terminus of TRPV1 modulated by β-arrestin-2. In the present study we reveal that the phosphorylation status of Thr370 dictates the β-arrestin-2 and TRPV1 association. Furthermore, we demonstrate that CK2 (casein kinase 2)-mediated phosphorylation of β-arrestin-2 at Thr382 is critical for its association with TRPV1. Taken together, the findings of the present study suggest that phosphorylation controls the association of TRPV1 with β-arrestin-2.
The rapid acceleration model and the growth rate of a turbulent mixing zone induced by Rayleigh-Taylor instability
Authors: Gréa B.-J.
Published: January 2013

A nonlinear model giving the short-time dynamics of turbulent mixing layers of two incompressible miscible fluids submitted to strong accelerations is proposed. This model encompasses both the linear rapid distortion theory applied to unstably stratified flows and an equation of evolution for the mixing zone width L. The nonlinear mechanism coming from the interaction between the turbulent quantities and the mean concentration field leads to a self-similar regime. The convergence to this state is analyzed in depth using dynamical system techniques. In this framework, the existence of a central manifold is established and allows a reduction of dimension of the problem. This is associated with a Lagrangian formulation depending only on \documentclass[12pt]{minimal}\begin{document}$L, \dot{L}$\end{document}L,L̇ so that the dynamics of L degenerates into a buoyancy-drag equation. Here, the expression for the buoyancy coefficient is explicit. It depends only on the global mixing parameter and a quantity called the dimensionality parameter characterizing the form of density turbulent structures inside the mixing zone. An extension of the rapid acceleration model to the classical self-similar Rayleigh-Taylor problem is presented leading to an analytical expression for the growth parameter α, which is compared to existing numerical simulations and experiments.
Global existence of solution for thermally radiative magnetohydrodynamic equations with the displacement current
Authors: Zhang Jingjun , Guo Boling
Published: January 2013

In this paper, we study thermally radiative magnetohydrodynamic equations in the presence of the displacement current. By using exquisite energy estimate, global existence and uniqueness of strong solution are obtained under some general assumptions on the pressure and internal energy. This result generalizes the already known results for the thermally radiative magnetohydrodynamic equations without the displacement current.
Mechanisms of droplet formation and Bi incorporation during molecular beam epitaxy of GaAsBi
Authors: Vardar G. , Paleg S. W. , Warren M. V. , Kang M. , Jeon S. , Goldman R. S.
Published: January 2013

We have examined the mechanisms of droplet formation and Bi incorporation during molecular beam epitaxy of GaAsBi. We consider the role of the transition from group-V-rich to group-III-rich conditions, i.e., the stoichiometry threshold, in the presence of Bi. For As-rich GaAsBi growth, Bi acts as a surfactant, leading to the formation of droplet-free GaAsBi films. For films within 10% of the stoichiometric GaAsBi growth regime, surface Ga droplets are observed. However, for Ga-rich GaAsBi growth, Bi acts as an anti-surfactant, inducing Ga-Bi droplet formation. We propose a growth mechanism based upon the growth-rate-dependence of the stoichiometry threshold for GaAsBi.
Note: Simultaneous measurement of transverse speed and axial velocity from a single optical beam
Authors: Moro Erik A. , Briggs Matthew E.
Published: January 2013

A method is introduced for simultaneously measuring transverse speed and axial velocity using a single optical beam and a standard photon Doppler velocimetry (PDV) sensing architecture. This result is of particular interest given the recent, widespread use of PDV and the fact that optical velocimetry has thus far been limited to measuring motion in one dimension per probe. Further, this result demonstrates that both axial velocity data and transverse speed data (at least qualitative) may be obtained entirely through signal analysis; not requiring hardware modification. This result is immediately relevant to analyses of existing PDV data and to future efforts in high-speed optical velocimetry.
Direct observation of a multiple-peak structure in the Raman spectra of 74Ge and 70Ge nanocrystals
Authors: Levy Shai , Shlimak Issai , Dressler David H. , Lu Tiecheng
Published: January 2013

Raman scattering (RS) spectra were measured in samples of germanium nanocrystals (Ge-NC) prepared by ion-implantation of 74Ge and 70Ge isotopes into an amorphous SiO2 layer initially grown on a Si 〈100〉 surface. A rich multiple-peak structure has been detected in addition to the well-known Ge-Ge peak at about 300 cm−1 of bulk Ge. Specifically, new 74Ge-NC-related peaks centered around 202 cm−1, 217 cm−1, and 317 cm−1 were directly observed as verified by isotopic Raman shift in 70Ge-NC samples. Lorentzian line shape fit of the RS spectra implies the existence of two additional Ge-related vibration modes around 260 cm−1 and 360 cm−1. The origin of each of the Ge related peaks was determined using a theoretical calculation based on the harmonic approximation.
Growth, structure and dielectric characteristics of Ba[(Fe1/2Nb1/2)0.1Ti0.9]O3 thin films by pulsed laser deposition
Authors: Zhang Wei , Li Lei , Ming Chen Xiang
Published: January 2013

Ba[(Fe1/2Nb1/2)0.1Ti0.9]O3 thin films were grown on Pt/TiO2/SiO2/Si substrates by pulsed laser deposition at 823 and 923 K. X-ray diffraction analysis suggested the cubic perovskite structure at room temperature. The dielectric properties were investigated at various frequencies (100–106 Hz). Three dielectric abnormalities were observed in the temperature range of 120 to 400 K. The abrupt change in dielectric constant and dielectric loss around 288 K demonstrated the diffused ferroelectric behavior of the thin films. The polarization-electric filed (P-E) loops were measured at different temperatures. Slimmer P-E hysteresis loops were observed with increasing temperature. Raman spectra of Ba[(Fe1/2Nb1/2)0.1Ti0.9]O3 thin films at room temperature indicated local C4v symmetry caused by the displacement of Ti4+ ions. Extra Raman peaks in the thin films compared to that of the bulk ceramic implied extra structure distortion in the thin films. The stress relating to the misfit of the thermal expansion coefficient between the substrate and the thin film might contribute the structure distortion in the thin films.
Monolithic integrated enhancement/depletion-mode AlGaN/GaN high electron mobility transistors with cap layer engineering
Authors: Kong Yuechan , Zhou Jianjun , Kong Cen , Dong Xun , Zhang Youtao , Lu Haiyan , Chen Tangsheng
Published: January 2013

Monolithic integrated enhancement/depletion (E/D)-mode AlGaN/GaN high electron mobility transistors (HEMTs) are fabricated on an AlGaN/GaN heterostructure with an engineered triple-cap-layer. The energy band of the cap layer is greatly tailored by the polarizations within it, which improves the controllability of D-to-E mode conversion with gate recess. The uniformity of the threshold voltage (Vth) across a 3″ wafer is assessed and the standard deviations of Vth are 0.1 V and 0.14 V for E-mode and D-mode devices, respectively. Direct-coupled field-effect transistor logic E/D HEMT inverter and 17-stage ring oscillator are demonstrated, and the latter shows a oscillation frequency of 201 MHz at a supply voltage of 1 V, corresponding to a propagation delay of 146 ps/stage and a power-delay product of 1.96 pJ/stage.
Thickness dependent red shift of the photocurrent spectrum in bulk heterojunction solar cells
Authors: Abeyweera B. K. , Alphenaar B. W.
Published: January 2013

Photocurrent spectra are measured for two different types of bulk heterojunction organic solar cells having a range of active layer thicknesses. Normalized by the number of incident photons, the photocurrent peak red shifts with respect to the absorption maximum as the sample thickness increases. Comparison to photocurrent measurements made with a chopped light source shows that the shift is due to an increased contribution from long wavelength absorption in the central active region. Fitting the thickness dependent photocurrent to a charge recombination model provides a measure of carrier collection lengths and surface recombination.
Self-organized Archimedean spiral pattern: Regular bundling of fullerene through solvent evaporation
Authors: Chen Yong-Jun , Suzuki Kosuke , Mahara Hitoshi , Yoshikawa Kenichi , Yamaguchi Tomohiko
Published: January 2013

We report the spontaneous generation of an Archimedean spiral pattern of fullerene via the evaporation of solvent. The self-organized spiral pattern exhibited equi-spacing on the order of μm between neighboring stripes. The characteristics of the spirals, such as the spacing between stripes, the number of stripes, and the band width of stripes, could be controlled by tuning the thickness of the liquid bridge and the concentration of solution. The mechanism of pattern formation is interpreted in terms of a specific traveling wave on the liquid-solid interface accompanied by a stick-slip process of the contact line.
A possible origin of core-level shift in SiO2/Si stacks
Authors: Wang Xiaolei , Xiang Jinjuan , Wang Wenwu , Zhang Jing , Han Kai , Yang Hong , Ma Xueli , Zhao Chao , Chen Dapeng , Ye Tianchun
Published: January 2013

Band alignments of SiO2/Si stacks with different SiO2 thicknesses are re-examined by X-ray photoelectron spectroscopy (XPS) and X-ray Auger electron spectroscopy. The energy difference between core-levels of SiO2 and Si is found to decrease with thicker SiO2. A possible explanation based on surface gap states (SGS) and charge neutrality level (CNL) is proposed to elucidate band alignment of SiO2/Si. Due to lower CNL of SiO2 SGS than Fermi level of Si, electrons transfer from Si to SiO2 SGS. With thicker SiO2 fewer electrons transfer from Si to SiO2, resulting in larger potential drop across SiO2 and XPS results.
Blue shift of plasmonic resonance induced by nanometer scale anisotropy of chemically synthesized gold nanospheres
Authors: Watanabe-Tamaki Ryoko , Ishikawa Atsushi , Tanaka Takuo
Published: January 2013

Anisotropic plasmonic responses on oblate spheroidal shape were investigated using chemically synthesized gold nanospheres. By employing the polarized transmission spectroscopy with oblique incidence, we observe 12-nm blue shift of the plasmonic resonant wavelength for gold nanospheres. The gold nanospheres with 3-nm deformation exhibited anisotropy by adsorbing on a substrate surface, resulting in the blue shift of plasmon resonant wavelength. The good agreement in measured and simulated transmission spectra leads to a precise design of gold nanospheres for plasmonic applications.
Fluorescent molecules offer another route to efficient organic LEDs
Authors: Miller Johanna L.
Published: January 2013

The new materials bypass the need for costly heavy metals.
Lagrangian coherent structures: The hidden skeleton of fluid flows
Authors: Peacock Thomas , Haller George
Published: January 2013

New techniques promise better forecasting of where damaging contaminants in the ocean or atmosphere will end up.
Too Much Food and Too Little Sidewalk? Problematizing the Obesogenic Environment Thesis
Authors: Guthman Julie
Published: January 2013

The obesogenic environment thesis is that increased prevalence of obesity is because people are surrounded by cheap, fast, nutritionally inferior food and a built environment that discourages physical activity. This thesis has animated various planning, advocacy, and educational interventions to address these obesogenic qualities. However, studies designed to test the thesis have generated inconclusive or marginal results, and the more robust findings may be based on spurious correlations. Part of the problem is methodological: researchers embed many assumptions in their models and derive causality from unexamined correlation. As such, they neglect the possibility that features of the built environment may be as much an effect of sociospatial patterning as a cause. In addition, in embedding taken-for-granted assumptions about the causes of obesity—namely, the energy-balance model—these studies foreclose alternative explanations, including the possible role of environmental toxins. This approach to studying the obesogenic environment is a textbook example of problem closure, in which a specific definition of a problem and socially acceptable solutions are used to frame the study of the problem's causes and consequences.
Gentrification or ‘Multiplication of the Suburbs’? Residential Development in New Zealand's Coastal Countryside
Authors: Collins Damian
Published: January 2013

This paper conceptualizes recent residential development in New Zealand's coastal countryside, which has entailed dramatic escalations in land and housing values. It considers whether this process should be understood as gentrification, as has recently been suggested. The argument against this interpretation is twofold. First, some qualities of coastal development that echo themes in the rural gentrification literature may be better understood as characteristics of a buoyant real estate market. Second, various central elements of rural gentrification are absent. These include restoration and reuse of the built environment, a shift in locational preferences prompting in-migration, and countercultural lifestyle opportunities. The process is also unlikely to cause significant direct displacement, as growth has proceeded in large part through greenfield new-build. An alternative, and long-standing, conceptualization of rural coastal development in New Zealand is as a type of suburbanization. The reproduction of suburban forms and functions is illustrated with reference to a case study from the Northland region. The paper emphasizes that definitions of gentrification need to be tailored so as not to capture any type of real estate-related investment and upgrading.
Photosynthetic reaction center as a quantum heat engine
Authors: Dorfman Konstantin E. , Voronine Dmitri V. , Mukamel Shaul , Scully Marlan O.
Published: January 2013

Two seemingly unrelated effects attributed to quantum coherence have been reported recently in natural and artificial light-harvesting systems. First, an enhanced solar cell efficiency was predicted and second, population oscillations were measured in photosynthetic antennae excited by sequences of coherent ultrashort laser pulses. Because both systems operate as quantum heat engines (QHEs) that convert the solar photon energy to useful work (electric currents or chemical energy, respectively), the question arises whether coherence could also enhance the photosynthetic yield. Here, we show that both effects arise from the same population–coherence coupling term which is induced by noise, does not require coherent light, and will therefore work for incoherent excitation under natural conditions of solar excitation. Charge separation in light-harvesting complexes occurs in a pair of tightly coupled chlorophylls (the special pair) at the heart of photosynthetic reaction centers of both plants and bacteria. We show the analogy between the energy level schemes of the special pair and of the laser/photocell QHEs, and that both population oscillations and enhanced yield have a common origin and are expected to coexist for typical parameters. We predict an enhanced yield of 27% in a QHE motivated by the reaction center. This suggests nature-mimicking architectures for artificial solar energy devices.
Public policy as information
Authors: Stewart Jenny
Published: January 2013

Clearly, public policy-making is an activity that both generates and uses information. Both the role of public policy in relation to informational assets and the role of information technologies have been widely canvassed, But can the concept of information itself be used analytically to understand public policy-making? In pursuit of this objective, key theories of public policy are re-interpreted from an informational perspective using a process of reciprocal interrogation. From this analysis, three types of informational role are identified within the policy process: response, control and accountability; structured interaction; and meaning-making. In summary, it is argued that public policy enables collective responses to problems to be formulated and implemented through information transmission and signalling. Through institutional pattern-making, public policy structures and selects information flows. Finally, information forms the basis of meaning-making in public policy. As a result of this exploration, some suggestions are made as to how these concepts may be used to improve policy-making.
Laser-induced Fluorescence Spectroscopy of NiCl in 12900–15000 cm−1
Authors: Qin Cheng-bing , Zang Jian-zheng , Zhang Qun , Chen Yang
Published: January 2013

Laser-induced fluorescence excitation spectra of jet-cooled NiCl molecules were recorded in the energy range of 12900–15000 cm−1. Six vibronic bands with rotational structure have been observed and assigned to the [13.0]2Π3/2(ν′= 0–5)-X2Π3/2(ν″=0) transition progression. The relevant rotational constants, significant isotopic shifts, and (equilibrium) molecular parameters have been determined. In addition, the lifetimes of the observed bands have also been measured.
Softening of C—H Symmetric Stretching Vibrational Modes for CH2 and CH3 Radicals Adsorbed on Cun(n=1–6) Clusters
Authors: Cheng Xi-hui , Ding Da-jun , Yu Yong-gang , Jin Ming-xing
Published: January 2013

The properties of C—H vibration softening for CH2 and CH3 radicals absorbed on Cun (n=1–6) clusters have been investigated, using the density functional theory with hybrid functional. The results indicate that the absorption of CH2 on Cu clusters is stronger than the case of CH3. The vibrational frequencies of C—H bonding agree with the experimental results obtained for CH2 and CH3 absorbed on Cu(111). With the increase of cluster size, the softening (Einstein shift) of C—H vibrational modes become stronger.
Red Emission of Eu(III) Complex Based on 1-(7-(tert-butyl)-9-ethyl-9H-carbazol-2-yl)-4,4,4-trifluorobutane-1,3-dione Excited by Blue Light
Authors: Liu Sheng-gui , Su Wen-yi , Pan Rong-kai , Zhou Xiao-ping
Published: January 2013

A new Eu(III) complex, EuL3(phen), was synthesized, where L is the abbreviation of deprotonated 1-(7-(tert-butyl)-9-ethyl-9H-carbazol-2-yl)-4,4,4-trifluorobutane-1,3-dione(HL), phen is the abbreviation of 1,10-phenanthroline. The Eu(III) complex was characterized by element analysis, IR, 1H NMR, UV-visible absorption spectroscopy, thermogravimetric analysis (TGA), and photoluminescence measurements (PL). TGA shows that thermal stability of the complex is up to 325 °C. PL measurement indicates that the Eu(III) complex exhibits intense red-emission and extends their excitation bands to visible region. LEDs device was successfully fabricated by precoating complex EuL3(phen) onto 460 nm blue-emitting InGaN chip. The emission of device shows that the complex can act as red phosphor in combination with 460 nm blue-emitting chips. This europium complex based on 1-(7-(tert-butyl)-9-ethyl-9H-carbazol-2-yl)-4,4,4-trifluorobutane-1,3-dione is a kind of interesting red-emitting material excited by blue light, which could avoid the damage of excitation by UV light.
Growth and Electronic Properties of Ag Nanoparticles on Reduced CeO2−x(111) Films
Authors: Kong Dan-dan , Pan Yong-he , Wang Guo-dong , Pan Hai-bin , Zhu Jun-fa
Published: January 2013

Ag nanoparticles grown on reduced CeO2−x thin films have been studied by X-ray photoelectron spectroscopy and resonant photoelectron spectroscopy of the valence band to understand the effect of oxygen vacancies in the CeO2−x thin films on the growth and interfacial electronic properties of Ag. Ag grows as three-dimensional particles on the CeO2−x(111) surface at 300 K. Compared to the fully oxidized ceria substrate surface, Ag favors the growth of smaller particles with a larger particle density on the reduced ceria substrate surface, which can be attributed to the nucleation of Ag on oxygen vacancies. The binding energy of Ag3d increases when the Ag particle size decreases, which is mainly attributed to the final-state screening. The interfacial interaction between Ag and CeO2−x(111) is weak. The resonant enhancement of the 4f level of Ce3+ species in RPES indicates a partial Ce4+→Ce3+ reduction after Ag deposited on reduced ceria surface. The sintering temperature of Ag on CeO1.85(111) surface during annealing is a little higher than that of Ag on CeO2(111) surface, indicating that Ag nanoparticles are more stable on the reduced ceria surface.
Means of self-preservation: how an intrinsically disordered ubiquitin-protein ligase averts self-destruction
Authors: Fredrickson Eric K. , Clowes Candadai Sarah V. , Tam Cheuk Ho , Gardner Richard G.
Published: January 2013

Ubiquitin-protein ligases (E3s) that ubiquitinate substrates for proteasomal degradation are often in the position of ubiquitinating themselves due to interactions with a charged ubiquitin-conjugating enzyme (E2). This can mediate the E3’s proteasomal degradation. Many E3s have evolved means to avoid autoubiquitination, including protection by partner or substrate binding, preventative modifications, and deubiquitinating enzyme reversal of ubiquitination. Here we describe another adaptation for E3 self-protection discovered while exploring San1, which ubiquitinates misfolded nuclear proteins in yeast for proteasomal degradation. San1 is highly disordered in its substrate-binding regions N- and C-terminal to its RING domain. In cis autoubiquitination could occur if these flexible regions come in proximity to the E2. San1 prevents this by containing no lysines in its disordered regions; thus the canonical residue used for ubiquitin attachment has been selectively eliminated. San1’s target substrates have lost their native structures and expose hydrophobicity. To avoid in trans autoubiquitination, San1 possesses little concentrated hydrophobicity in its disordered regions, and thus the that feature San1 recognizes in misfolded substrates has also been selectively eliminated. Overall the presence of key residues in San1 have been evolutionarily minimized to avoid self-destruction either in cis or in trans. Our work expands the ways in which E3s protect themselves from autoubiquitination.