bluuebunny/crossref_metadata_2025 huggingface dataset:
Entwicklungserwartungen deutscher und türkisch-deutscher Mütter von Vorschulkindern
Authors: Otyakmaz Berrin Özlem
Published: December 2012

Zusammenfassung. Kulturvergleichende Untersuchungen haben gezeigt, dass sich Mütter hinsichtlich ihrer Erwartungen, wann Kinder bestimmte (z. B. kognitive, motorische, soziale) Fähigkeiten entwickelt haben sollten, kulturell unterscheiden. In dieser Studie wurden die Entwicklungserwartungen von 107 türkisch-deutschen und 127 deutschen Mütter mit Kindern im Vorschulalter mit einem Instrument erfasst, das aus 61 Items besteht, die acht Entwicklungsbereichen angehören. Türkisch-deutsche Mütter erwarteten das Erreichen der Entwicklungsschritte in fast allen Domänen später als deutsche Mütter. Das Ergebnis wird im Hinblick auf die spezifische Ethnotheorie türkisch-deutscher Mütter diskutiert, die einen Einfluss auf ihre Entwicklungserwartungen haben könnte.
Perceptions of a Peer Suicide Prevention Program by Inmates and Professionals Working in Prisons
Authors: Auzoult Laurent , Abdellaoui Sid
Published: December 2012

Background: Suicide prevention is a major challenge for penal institutions in many countries. The traditional approach relies on the expertise of health professionals and is supplemented by the intervention of other professionals and the inmates themselves. New methods of suicide prevention based on peer support have been developed in recent years. Peer prevention programs rely on the ability of inmates to identify suicide risk. Aims: This study examines perceived suicide risk among inmates and explores possible explanations. Method: 54 inmates and 17 professionals working in prisons responded to a questionnaire. Results: The peer prevention program was found to change inmates’ expectations of support in the event of a suicide crisis. The study also found that the inmates involved in the program tended to underestimate the risk of suicide. The perception of the prevention program and the level of self-consciousness were found to account for the underestimation of suicide risk. Conclusions: Support for inmates involved in suicide prevention programs must take into account their isolation in prison. The training provided to inmates must also consider the biases affecting the assessment of risk.
Which Suicides Are Reported in the Media – and What Makes Them “Newsworthy”?
Authors: Machlin Anna , Pirkis Jane , Spittal Matthew J.
Published: December 2012

Background: Media reporting of suicide has attracted public health attention because of its potential to trigger “copycat” acts. Aims: To determine the factors associated with an individual suicide featuring in the media. Method: We identified from the National Coroners Information System (NCIS) all suicides that occurred in Australia over a 1-year period and established those that were reported in the Australian media using data from our earlier Media Monitoring Project. Available variables were used to examine factors associated with a suicide being reported in the media. Results: Of the 2,161 suicides, 29 were reported in the media. Suicides by younger individuals were particularly likely to be reported, as were suicides by gunshot and other violent methods, suicides in commercial areas (e.g., office buildings and hotels) and medical/residential facilities and other institutions (e.g., detention centers), and suicides that occurred in the context of multiple fatality events (e.g., homicide-suicides and suicide pacts). Conclusions: Striking the right balance in terms of media reporting of suicide is crucial. The current study suggests that the reported suicides tend to be those that may either heighten the risk of lethal imitative behaviors or serve to distort public perceptions about suicide.
The Impact of Universal Suicide-Prevention Programs on the Help-Seeking Attitudes and Behaviors of Youths
Authors: Klimes-Dougan Bonnie , Klingbeil David A. , Meller Sarah J.
Published: December 2012

Background: While the ultimate goal of adolescent suicide-prevention efforts is to decrease the incidence of death by suicide, a critical intermediary goal is directing youths toward effective sources of assistance. Aim: To comprehensively review the universal prevention literature and examine the effects of universal prevention programs on student’s attitudes and behaviors related to help-seeking. Method: We systematically reviewed studies that assessed help-seeking outcomes including prevention efforts utilizing (1) psychoeducational curricula, (2) gatekeeper training, and (3) public service messaging directed at youths. Of the studies reviewed, 17 studies evaluated the help-seeking outcomes. These studies were identified through a range of sources (e.g., searching online databases, examining references of published articles on suicide prevention). Results: The results of this review suggest that suicide-prevention programming has a limited impact on help-seeking behavior. Although there was some evidence that suicide-prevention programs had a positive impact on students’ help-seeking attitudes and behaviors, there was also evidence of no effects or iatrogenic effects. Sex and risk status were moderators of program effects on students help-seeking. Conclusions: Caution is warranted when considering which suicidal prevention interventions best optimize the intended goals. The impact on adolescents’ help-seeking behavior is a key concern for educators and mental-health professionals.
Perceived Need for Care and Health Care Utilization Among Depressed and Anxious Patients With and Without Suicidal Ideation
Authors: Stringer Barbara , van Meijel Berno , Eikelenboom Merijn , Koekkoek Bauke , Verhaak Peter F. M. , Kerkhof Ad J. M. F. , Penninx Brenda W. J. H. , Beekman Aartjan T. F.
Published: December 2012

Background: Information is scarce concerning the perceived needs and the amount of health-care utilization of persons with suicidal ideation (SI) compared to those without SI. Aims: To describe the needs and health care use of persons with and without SI and to investigate whether these differences are associated with the severity of the axis-I symptomatology. Method: Data were obtained from 1,699 respondents with a depressive and/or anxiety disorder who participated in the Netherlands Study of Depression and Anxiety. Persons with and without SI were distinguished. Outcome variables were perceived needs and health-care utilization. We used multivariate regression in two models: (1) adjusted only for sociodemographic variables and (2) adjusted additionally for severity of axis-I symptomatology. Results: Persons with SI had higher odds for both unmet and met needs in almost all domains and made more intensive use of mental-health care. Differences in needs and health-care utilization of persons with and without SI were strongly associated with severity of axis I symptomatology. Conclusions: Our results validate previous findings about perceived needs and health-care use of persons with SI. The results also suggest that suicidal persons are more seriously ill, and that they need more professional care, dedication, and specialized expertise than anxious and depressed persons without SI, especially in the domains of information and referral.
Adaptive Memory
Authors: VanArsdall Joshua E. , Nairne James S. , Pandeirada Josefa N. S. , Blunt Janell R.
Published: December 2012

It is adaptive to remember animates, particularly animate agents, because they play an important role in survival and reproduction. Yet, surprisingly, the role of animacy in mnemonic processing has received little direct attention in the literature. In two experiments, participants were presented with pronounceable nonwords and properties characteristic of either living (animate) or nonliving (inanimate) things. The task was to rate the likelihood that each nonword-property pair represented a living thing or a nonliving object. In Experiment 1, a subsequent recognition memory test for the nonwords revealed a significant advantage for the nonwords paired with properties of living things. To generalize this finding, Experiment 2 replicated the animate advantage using free recall. These data demonstrate a new phenomenon in the memory literature – a possible mnemonic tuning for animacy – and add to growing data supporting adaptive memory theory.
Selective Interference of Finger Movements on Basic Addition and Subtraction Problem Solving
Authors: Michaux Nicolas , Masson Nicolas , Pesenti Mauro , Andres Michael
Published: December 2012

Fingers offer a practical tool to represent and manipulate numbers during the acquisition of arithmetic knowledge, usually with a greater involvement in addition and subtraction than in multiplication. In adults, brain-imaging studies show that mental arithmetic increases activity in areas known for their contribution to finger movements. It is unclear, however, if this truly reflects functional interactions between the processes and/or representations controlling finger movements and those involved in mental arithmetic, or a mere anatomical proximity. In this study we assessed whether finger movements interfere with basic arithmetic problem solving, and whether this interference is specific for the operations that benefit the most from finger-based calculation strategies in childhood. In Experiment 1, we asked participants to solve addition, subtraction, and multiplication problems either with their hands at rest or while moving their right-hand fingers sequentially. The results showed that finger movements induced a selective time cost in solving addition and subtraction but not multiplication problems. In Experiment 2, we asked participants to solve the same problems while performing a sequence of foot movements. The results showed that foot movements produced a nonspecific interference with all three operations. Taken together, these findings demonstrate the specific role of finger-related processes in solving addition and subtraction problems, suggesting that finger movements and mental arithmetic are functionally related.
β
-expansion attractors observed in A/D converters
Authors: Kohda Tohru , Horio Yoshihiko , Aihara Kazuyuki
Published: December 2012

The recently proposed β-encoders, analog-to-digital converters using an amplifier with a factor β and a flaky quantizer with threshold ν, have proven to be explained by the deterministic dynamics of multi-valued Rényi-Parry maps. Such a map is locally eventually onto [ν−1, ν), which is topologically conjugate to Parry's (β,α)-map with α=(β−1)(ν−1). This implies that β-encoders have a closed subinterval [ν−1,ν), which includes an attractor. Thus, the iteration of the multi-valued Rényi-Parry map performs the β-expansion of x while quantization errors in β-encoders behave chaotically and do not converge to a fixed point. This β-expansion attractor is relatively simpler than previously reported attractors. The object of this paper is twofold: to observe the embedded attractors in the β-encoder and to identify attractors that are useful for spread-spectrum codes and optimization techniques using pseudo-random numbers.
μ-Raman spectroscopy characterization of LiNbO3 femtosecond laser written waveguides
Authors: Tejerina M. R. , Jaque D. , Torchia G. A.
Published: December 2012

In this paper, we present an iterative method which merges experimental μ-Raman measurements and numerical simulations to describe femtosecond written waveguides in LiNbO3 crystals. This method is based on the deformation potential theory, and uses the finite element method to analyze elastic deformations after femtosecond laser micro-explosions in x-cut Mg:LiNbO3 crystals. The resultant strain and refractive index field after laser interaction were estimated and yielded similar values to those obtained in other works. The LiNbO3 Raman deformation potential constants were also estimated in this work.
Advance in multi-hit detection and quantization in atom probe tomography
Authors: Costa G. Da , Wang H. , Duguay S. , Bostel A. , Blavette D. , Deconihout B.
Published: December 2012

The preferential retention of high evaporation field chemical species at the sample surface in atom-probe tomography (e.g., boron in silicon or in metallic alloys) leads to correlated field evaporation and pronounced pile-up effects on the detector. The latter severely affects the reliability of concentration measurements of current 3D atom probes leading to an under-estimation of the concentrations of the high-field species. The multi-hit capabilities of the position-sensitive time-resolved detector is shown to play a key role. An innovative method based on Fourier space signal processing of signals supplied by an advance delay-line position-sensitive detector is shown to drastically improve the time resolving power of the detector and consequently its capability to detect multiple events. Results show that up to 30 ions on the same evaporation pulse can be detected and properly positioned. The major impact of this new method on the quantization of chemical composition in materials, particularly in highly-doped Si(B) samples is highlighted.
On transition rates in surface hopping
Authors: Escartín J. M. , Romaniello P. , Stella L. , Reinhard P.-G. , Suraud E.
Published: December 2012

Trajectory surface hopping (TSH) is one of the most widely used quantum-classical algorithms for nonadiabatic molecular dynamics. Despite its empirical effectiveness and popularity, a rigorous derivation of TSH as the classical limit of a combined quantum electron-nuclear dynamics is still missing. In this work, we aim to elucidate the theoretical basis for the widely used hopping rules. Naturally, we concentrate thereby on the formal aspects of the TSH. Using a Gaussian wave packet limit, we derive the transition rates governing the hopping process at a simple avoided level crossing. In this derivation, which gives insight into the physics underlying the hopping process, some essential features of the standard TSH algorithm are retrieved, namely (i) non-zero electronic transition rate (“hopping probability”) at avoided crossings; (ii) rescaling of the nuclear velocities to conserve total energy; (iii) electronic transition rates linear in the nonadiabatic coupling vectors. The well-known Landau-Zener model is then used for illustration.
Nonlinear dielectric response in piezoelectric materials for underwater transducers
Authors: Sherlock N. P. , Garten L. M. , Zhang S. J. , Shrout T. R. , Meyer R. J.
Published: December 2012

SONAR transducers based on single crystal lead magnesium niobate-lead titanate (PMNT) have demonstrated improvements over conventional lead zirconate titanate ceramics. Compositional modifications to PMNT have combined the high piezoelectric coefficient (d33 > 2000 pC/N) and electromechanical coupling factor (k33 > 0.90) with the low mechanical losses (QM > 1000) of “hard” piezoelectric ceramics. The dielectric losses of single crystal PMNT have not been investigated as extensively as the mechanical losses but may significantly affect the performance of a device when water loaded. In this work, nonlinearities in the dielectric permittivity and losses have been investigated as a function of applied electric field, measurement frequency, and temperature. It is shown that electromechanically “hard” single crystals offer greater stability of the dielectric properties while maintaining a high permittivity with respect to conventional lead zirconate titanate ceramics.
Transport and magnetic properties of Fe doped CaMnO3
Authors: Neetika  , Das A. , Dhiman I. , Nigam A. K. , Yadav A. K. , Bhattacharyya D. , Meena S. S.
Published: December 2012

The structural, transport, and magnetic properties of CaMn1−xFexO3−δ (0.0 ≤ x ≤ 0.3) have been studied by using resistivity, magnetization, and neutron powder diffraction techniques. The compounds are found to be isostructural and crystallize in GdFeO3-type orthorhombic structure (space group Pnma). With Fe doping, no structural change is observed. Mössbauer and paramagnetic susceptibility measurements show that Fe substitutes in 4+ valence state, and XANES measurements indicate the presence of mixed valence state of Mn. The compounds exhibit insulating behavior in the studied temperature range. The temperature dependence of resistivity is found to be described by small polaron model for x = 0 and variable range hopping model for x = 0.1. For higher x values, it follows a parallel combination resistance model. A small reduction in TN from 120 K to 100 K with increase in x is found. The magnetic structure changes from Gz-type collinear antiferromagnetic (AFM) structure for x = 0.0 to canted AFM structure GZFY-type for Fe doped compounds. The AFM component of the moment progressively decreases with x while FM component exhibits a maximum at x = 0.2.
Intraband absorption in finite, inhomogeneous quantum dot stacks for intermediate band solar cells: Limitations and optimization
Authors: Bragar Igor , Machnikowski Paweł
Published: December 2012

We present a theoretical analysis of intraband optical transitions from the intermediate pseudo-band of confined states to the conduction band in a finite, inhomogeneous stack of self-assembled semiconductor quantum dots (QDs). The chain is modeled with an effective Hamiltonian including nearest-neighbor tunnel couplings and the absorption under illumination with both coherent (laser) and thermal radiation is discussed. We show that the absorption spectrum already for a few coupled dots differs from that of a single dot and develops a structure with additional maxima at higher energies. We find out that this leads to an enhancement of the overall transition rate under solar illumination by up to several percent which grows with the number of QDs but saturates already for a few QDs in the chain. The decisive role of the strength of inter-dot coupling for the stability of this enhancement against QD stack inhomogeneity and temperature is revealed.
Effect of surface alignment layer and polymer network on the Helfrich deformation in cholesteric liquid crystals
Authors: Nemati H. , Yang D.-K. , Cheng K.-L. , Liang C.-C. , Shiu J.-W. , Tsai C.-C. , Zola R. S.
Published: December 2012

We show that the Helfrich deformation can be used for fast response time, low driving voltage reflective displays by using cholesteric liquid crystals under short voltage pulses (∼10 ms). Rather than turning planar domains into focal conic domains through a nucleation process, as used in bistable modes, the fast voltage pulse only deforms the cholesteric planar layers to form wrinkled layers. Since the deformed state is formed through a homogeneous process, quick response times and low operating voltage can be achieved. We studied the effects of alignment layer and dispersed polymer on the stability of the Helfrich deformed cholesteric layers, and found that homogeneous alignment layer and polymer network can inhibit the nucleation process responsible for breaking the layers.
Alternating electric force microscopy: Static electric field gradient imaging in an air atmosphere for Ba0.7Sr0.3TiO3 ferroelectric thin film
Authors: Lu Jia , Kinoshita Yukinori , Egawa Genta , Yoshimura Satoru , Asano Hidefumi , Saito Hitoshi
Published: December 2012

An alternating electric force microscopy (A-EFM) technique, which is effective for the imaging of static electric field gradient in an air atmosphere, is proposed by using our developed alternating force microscopy. A-EFM uses a frequency modulation of a mechanically oscillating conductive tip, which is induced by applying off-resonant AC voltage to the tip. The AC voltage generates off-resonant alternating electric force at the tip. A-EFM detects static electric field gradient with the field polarity from a sample without involving surface forces by using a lock-in detection technique. For a Ba0.7Sr0.3TiO3 ferroelectric thin film, A-EFM clearly imaged the static electric field gradient with field polarity and the boundary of electric domain in an air atmosphere.
Diamond heat sinking of terahertz antennas for continuous-wave photomixing
Authors: Ackemann T. , Alduraibi M. , Campbell S. , Keatings S. , Luke Sam P. , Fraser H. , Arnold A. S. , Riis E. , Missous M.
Published: December 2012

The generation of cw Terahertz radiation from photomixing in low-temperature grown GaAs is limited by the thermal load for single emitters. We propose a new heat sinking scheme based on high thermal conductivity, transparent crystalline heat spreaders as diamond in direct contact with the active zone. A first working device based on recessed electrodes is demonstrated and has a significant power dissipation capability of more than 0.75 W (average). The electrical and terahertz characteristics are analyzed.
Electronic structure, small polaron, and F center in LiCaAlF6
Authors: Du Mao-Hua , Singh David J.
Published: December 2012

LiCaAlF6 (LiCAF) is a promising inorganic neutron scintillator material. Here, we report the electronic structure as well as properties of the small hole polaron and F center in LiCAF based on first-principles calculations. The results suggest that lowering the Fermi level by acceptor doping will stabilize F+ against F− and reduce the reabsorption of Ce emission by F centers in LiCAF:Ce3+, thereby increasing light yield and radiation resistance.
Resolving the phase structure of nonstoichiometric Co2FeGa Heusler nanoparticles
Authors: Wang Changhai , Casper Frederick , Guo Yanzhi , Gasi Teuta , Ksenofontov Vadim , Balke Benjamin , Fecher Gerhard H. , Felser Claudia , Hwu Yeu-Kuang , Lee Jey-Jau
Published: December 2012

Heusler nanocrystals, i.e., Heusler compounds with dimensions in nanometer range are promising materials for next-generation spin-related devices. Recently, we have developed a chemical approach to prepare L21 ordered Heusler nanoparticles and characterized their size-related structure and magnetic properties. In this work, effect of precursor composition is investigated in terms of their importance in controlling the phase structure of Co2FeGa nanoparticles. The formation of the L21 ordered Co2FeGa phase is evidenced by combining X-ray diffraction (XRD) and extended X-ray absorption fine structure (EXAFS) spectroscopy and Mössbauer spectroscopy measurements. From XRD, precursor compositions of low Co and high Fe are associated with decreasing amounts and even disappearance of fcc Co and fcc Fe impurities. We also find that, even though the XRD data indicate only pure Co2FeGa phase in sample with excess Fe, EXAFS and Mössbauer spectroscopy data unambiguously reveal the co-existence of bcc Fe with Co2FeGa main phase.
Patterning of templated-confined nanoscale Au films by thermal-induced dewetting process of a poly(methylmethacrylate) underlying layer
Authors: Ruffino F. , Torrisi V. , Marletta G. , Grimaldi M. G.
Published: December 2012

In this work, we propose a new approach to prepare surface micro-patterns in nanoscale deposited Au films. In particular, we exploit the idea to use a template confined dewetting aging not directly on the deposited Au film but on an underlying poly(methylmethacrylate) (PMMA) substrate by thermal processes. The idea consists of the following basic concepts: (a) to perform nanoscale Au film deposition assisted by micrometric templates to obtain a template confined film and (b) by low-temperature thermal processes (<400 °C) to induce a dewetting process of the PMMA to guide specific patterning effects in the top nanoscale Au film. In this approach, the Au surface pattern order is established by the template confined deposition on a micrometric scale (which is a highly efficient way to synthesize metallic surface patterns with controllable structures, large pattern areas, and to achieve a high throughput), while the realization and control of the Au surface pattern is given by the control of the dewetting process of the underlying substrate, without invoking high temperature thermal processes. We illustrate experimental results of such an approach, and we propose it as a model methodology for surface large scale micro-patterning of nanoscale metal films which can be applied to a wide range of systems towards device applications (i.e., plasmonics).
Localized interaction of single porphyrin molecules with oxygen vacancies on TiO2(110)
Authors: Lackinger Markus , Janson Martin S. , Ho W.
Published: December 2012

Alterations in the electronic structure of adsorbed zinc(II) etioporphyrin I (ZnEtio) through interaction with bridging oxygen vacancies on TiO2(110) are studied by scanning tunneling microscopy and spectroscopy at cryogenic temperatures under ultrahigh vacuum (UHV) conditions. Upon lateral manipulation of ZnEtio molecules above surface oxygen vacancies, the highest occupied molecular orbital shifts away from the Fermi level. The magnitude of the shift rapidly decreases with increasing distance of the molecule from the vacancy, indicating a highly localized interaction.
Universal programmable quantum circuit schemes to emulate an operator
Authors: Daskin Anmer , Grama Ananth , Kollias Giorgos , Kais Sabre
Published: December 2012

Unlike fixed designs, programmable circuit designs support an infinite number of operators. The functionality of a programmable circuit can be altered by simply changing the angle values of the rotation gates in the circuit. Here, we present a new quantum circuit design technique resulting in two general programmable circuit schemes. The circuit schemes can be used to simulate any given operator by setting the angle values in the circuit. This provides a fixed circuit design whose angles are determined from the elements of the given matrix–which can be non-unitary–in an efficient way. We also give both the classical and quantum complexity analysis for these circuits and show that the circuits require a few classical computations. For the electronic structure simulation on a quantum computer, one has to perform the following steps: prepare the initial wave function of the system; present the evolution operator U = e−iHt for a given atomic and molecular Hamiltonian H in terms of quantum gates array and apply the phase estimation algorithm to find the energy eigenvalues. Thus, in the circuit model of quantum computing for quantum chemistry, a crucial step is presenting the evolution operator for the atomic and molecular Hamiltonians in terms of quantum gate arrays. Since the presented circuit designs are independent from the matrix decomposition techniques and the global optimization processes used to find quantum circuits for a given operator, high accuracy simulations can be done for the unitary propagators of molecular Hamiltonians on quantum computers. As an example, we show how to build the circuit design for the hydrogen molecule.
Applied Koopmanism
Authors: Budišić Marko , Mohr Ryan , Mezić Igor
Published: December 2012

A majority of methods from dynamical system analysis, especially those in applied settings, rely on Poincaré's geometric picture that focuses on “dynamics of states.” While this picture has fueled our field for a century, it has shown difficulties in handling high-dimensional, ill-described, and uncertain systems, which are more and more common in engineered systems design and analysis of “big data” measurements. This overview article presents an alternative framework for dynamical systems, based on the “dynamics of observables” picture. The central object is the Koopman operator: an infinite-dimensional, linear operator that is nonetheless capable of capturing the full nonlinear dynamics. The first goal of this paper is to make it clear how methods that appeared in different papers and contexts all relate to each other through spectral properties of the Koopman operator. The second goal is to present these methods in a concise manner in an effort to make the framework accessible to researchers who would like to apply them, but also, expand and improve them. Finally, we aim to provide a road map through the literature where each of the topics was described in detail. We describe three main concepts: Koopman mode analysis, Koopman eigenquotients, and continuous indicators of ergodicity. For each concept, we provide a summary of theoretical concepts required to define and study them, numerical methods that have been developed for their analysis, and, when possible, applications that made use of them. The Koopman framework is showing potential for crossing over from academic and theoretical use to industrial practice. Therefore, the paper highlights its strengths in applied and numerical contexts. Additionally, we point out areas where an additional research push is needed before the approach is adopted as an off-the-shelf framework for analysis and design.
Measurement of contact voltage drop and resistance in organic solar cells
Authors: Williams Evan L. , Ooi Zien , Sonar Prashant , Dodabalapur Ananth
Published: December 2012

Bulk heterojunction organic solar cells based on poly[4,7-bis(3-dodecylthiophene-2-yl) benzothiadiazole-co-benzothiadiazole] and [6,6]-phenyl C71-butyric acid methyl ester are investigated. A prominent kink is observed in the fourth quadrant of the current density-voltage (J-V) response. Annealing the active layer prior to cathode deposition eliminates the kink. The kink is attributed to an extraction barrier. The J-V response in these devices is well described by a power law. This behavior is attributed to an imbalance in charge carrier mobility. An expected photocurrent for the device displaying a kink in the J-V response is determined by fitting to a power law. The difference between the expected and measured photocurrent allows for the determination of a voltage drop within the device. Under simulated 1 sun irradiance, the peak voltage drop and contact resistance at short circuit are 0.14 V and 90 Ω, respectively.
Portable double-sided laser-heating system for Mössbauer spectroscopy and X-ray diffraction experiments at synchrotron facilities with diamond anvil cells
Authors: Kupenko I. , Dubrovinsky L. , Dubrovinskaia N. , McCammon C. , Glazyrin K. , Bykova E. , Ballaran T. Boffa , Sinmyo R. , Chumakov A. I. , Potapkin V. , Kantor A. , Rüffer R. , Hanfland M. , Crichton W. , Merlini M.
Published: December 2012

The diamond anvil cell (DAC) technique coupled with laser heating is a major method for studying materials statically at multimegabar pressures and at high temperatures. Recent progress in experimental techniques, especially in high-pressure single crystal X-ray diffraction, requires portable laser heating systems which are able to heat and move the DAC during data collection. We have developed a double-sided laser heating system for DACs which can be mounted within a rather small (∼0.1 m2) area and has a weight of ∼12 kg. The system is easily transferable between different in-house or synchrotron facilities and can be assembled and set up within a few hours. The system was successfully tested at the High Pressure Station of White Beam (ID09a) and Nuclear Resonance (ID18) beamlines of the European Synchrotron Radiation Facility. We demonstrate examples of application of the system to a single crystal X-ray diffraction investigation of (Mg0.87,Fe3+0.09,Fe2+0.04)(Si0.89,Al0.11)O3 perovskite (ID09a) and a Synchrotron Mössbauer Source (SMS) study of (Mg0.8Fe0.2)O ferropericlase (ID18).
Polarization-resolved resonant fluorescence of a single semiconductor quantum dot
Authors: Robertson J. , Founta S. , Hughes M. , Hopkinson M. , Ramsay A. J. , Skolnick M. S. , Shih C. K.
Published: December 2012

We observe the resonantly excited emission of a single self assembled quantum dot (QD) positioned in a planar μ-cavity, free of any background scattering from defects in the surrounding lattice matrix. Making use of this technique, we are able to obtain the second-order correlation function g2(τ) and, therefore, observe its oscillations under strong continuous-wave excitation. By determining that its correlation function is near zero for g2(τ = 0), we are able to verify its status as a single quantum emitter. By altering the input scheme geometry, we are also able to demonstrate further direct control of a single QD's properties by gaining access to and observing emission from both of its polarization states πx and πy by merely tuning the excitation wavelength.
Investigation of carbon interstitials with varied SiO2 thickness in HfO2/SiO2/4H-SiC structure
Authors: Hsu Chia-Ming , Hwu Jenn-Gwo
Published: December 2012

The electrical performance of SiC-based devices is strongly affected by the border traps of high-k dielectrics and carbon (C) interstitials in SiC. The abrupt HfO2/ SiC junction exhibits frequency dispersion in capacitance–voltage (C-V) curves. The thin SiO2 (7.5 nm) sample that is without excess C clusters exhibits ideal C-V characteristics. With the increase of SiO2 thickness, excess C in SiC substrates is detected by using both auger electron spectroscopy and x-ray photoelectron spectroscopy. The thick SiO2 (15.5 nm) sample contains enormous excess C inside SiC close to SiO2 interface, and excess C changes the substrates to n+-like behavior.
Large decrease of characteristic frequency of dielectric relaxation associated with domain-wall motion in Sb5+-modified (K,Na)NbO3-based ceramics
Authors: Zhang Jialiang , Hao Wentao , Gao Yong , Qin Yalin , Tan Yongqiang , Wang Chunlei
Published: December 2012

The (K,Na)NbO3-based ceramics have drawn considerable attention as a type of promising lead-free piezoelectric materials in recent years. However, investigations on the dielectric dispersion spectra in the microwave range have rarely been conducted so far. Dielectric dispersion spectra of several representative (K,Na)NbO3-based ceramics were measured and compared in this study. An interesting physical phenomenon that the Sb5+-modified (K,Na)NbO3-based ceramics differ distinctly from those without Sb5+-modification in the aspect of characteristic frequency fp of dielectric relaxation associated with the domain-wall motion has been found. The former group shows the fp values in several tens of MHz at room temperature, whereas the latter group has generally the fp values of several GHz at least. For the Sb5+-modified (K,Na)NbO3-based ceramics, the change of fp with temperature follows roughly a thermally activated character. In contrast, the ones without Sb5+-modification exhibit a temperature-insensitive character in fp. Analysis showed that the results could be understood from the viewpoint of domain-wall vibration. It is speculated that a large change occurring in the damping constant due to the incorporation of Sb5+ is possibly the origin.
Random lasing in structures with multi-scale transport properties
Authors: Leonetti Marco , Lopez Cefe
Published: December 2012

In a random laser (RL), a system possessing in itself both resonator and amplifying medium while lacking a macroscopic cavity, the feedback is provided by the scattering, which forces light to travel very long random paths. Here, we demonstrate that RL properties may be tuned by the topology of the scattering system retaining unchanged scattering strength and gain efficiency. This is possible in a system based on sparse clusters, possessing two relevant structural lengths: the macroscopic inter cluster separation and the mesoscopic intra-cluster mean free path.
Widely tuned room temperature terahertz quantum cascade laser sources based on difference-frequency generation
Authors: Lu Q. Y. , Bandyopadhyay N. , Slivken S. , Bai Y. , Razeghi M.
Published: December 2012

We demonstrate room temperature THz quantum cascade laser sources with a broad spectral coverage based on intracavity difference-frequency generation. Two mid-infrared active cores based on the single-phonon resonance scheme are designed with a THz nonlinearity specially optimized at the high operating fields that correspond to the highest mid-infrared output powers. A Čerenkov phase-matching scheme along with integrated dual-period distributed feedback gratings are used for efficient THz extraction and spectral purification. Single mode emissions from 1.0 to 4.6 THz with a side-mode suppression ratio and output power up to 40 dB and 32 μW are obtained, respectively.
Large reduction in thermal conductivity for Ge quantum dots embedded in SiO2 system
Authors: Hung M.-T. , Wang C.-C. , Hsu J.-C. , Chiou J.-Y. , Lee S.-W. , Hsu T. M. , Li P.-W.
Published: December 2012

Thermal conductivity (k(T)) of Ge quantum dots (QDs) embedded in SiO2 was investigated at T = 100–400 K. The Ge QD/SiO2 system appears to have much lower k(T) than their counterparts of bulk Ge and SiO2, and the reduction factor increases with the surface-to-volume ratio of the QD in SiO2. Attendant to reduced magnitude includes delayed Umklapp decline and weaker dependence on temperature for k(T). Effective medium analysis suggests the reduction in k primarily comes from the decreased group velocity thanks to the QD inclusion that induces interfacial stress on SiO2, phonon confinement, and boundary scatterings.
Enhanced magneto-impedance in Fe73.5Cu1Nb3Si13.5B9 ribbons from laminating with magnetostrictive terfenol-D alloy plate
Authors: Jia Yanmin , Zheng Chen , Wu Zheng , Zheng R. K. , Fang Yunzhang , Zhang Yihe , Li Huamei
Published: December 2012

The authors report an amplified magneto-impedance (MI) in a laminated composite composed of a magnetostrictive terfenol-D plate and a Fe73.5Cu1Nb3Si13.5B9 ribbon that exhibits an intrinsic MI. When a dc magnetic field is applied to a laminated composite, the magnetostriction from the terfenol-D plate induces a giant stress that is simultaneously transferred to the ribbon, generating a stress-induced impedance (SI). Combining the terfenol-D magnetostriction and the SI of the ribbon produces an enhanced MI. The maximum MI ratio for the composite is ∼74%, which is ∼27 times higher than that for a single ribbon.
Pediatric Infectious Diseases Fellowship Training in Healthcare Epidemiology A National Needs Assessment
Authors: Sandora Thomas J. , Esbenshade Jennifer C. , Bryant Kristina A. ,   on behalf of the Pediatric Leadership Council of SHEA
Published: December 2012

Objective.

Pediatric infectious diseases (ID) fellows are required to receive training in hospital epidemiology and infection control and prevention. We sought to assess the current state of healthcare epidemiology training for fellows and to determine which topics are considered important by key stakeholders.

Participants.

US pediatric ID fellowship program directors and hospital epidemiologists.

Methods.

We conducted an anonymous Web-based survey in February 2012. We assessed the presence and content of curricula, perceived importance of specific topics, and barriers to career development.

Results.

Of 97 eligible participants, 76 (78%) completed the survey, representing 54 programs. Respondents were program directors (60%), hospital epidemiologists (25%), or both (15%). A total of 82% of programs with didactic curricula have infection control sessions, most commonly 1–2 hours in total duration. Of 17 identified topics, only 3 were covered by more than 50% of programs: isolation precautions (54%), central line-associated bloodstream infection (CLABSI; 53%), and hand hygiene (51%). Of the 76 respondents, 35% indicated that fellows participate in a dedicated infection control rotation. Six topics were considered very important by more than 75% of respondents: antimicrobial stewardship (94%), isolation precautions (93%), hand hygiene (90%), CLABSI (90%), surveillance for resistant bacteria (81%), and communicable disease exposure management (81%).

Conclusions.

Pediatric ID fellowship programs dedicate little time to didactic or experiential learning in healthcare epidemiology. There are a wide array of topics that the majority of programs do not cover, including several subjects that are considered to be very important by program directors and hospital epidemiologists. Creating a standardized pediatric infection control curriculum would likely benefit fellows in training.
MYADM controls endothelial barrier function through ERM-dependent regulation of ICAM-1 expression
Authors: Aranda Juan F. , Reglero-Real Natalia , Marcos-Ramiro Beatriz , Ruiz-Sáenz Ana , Fernández-Martín Laura , Bernabé-Rubio Miguel , Kremer Leonor , Ridley Anne J. , Correas Isabel , Alonso Miguel A. , Millán Jaime
Published: December 2012

The endothelium maintains a barrier between blood and tissue that becomes more permeable during inflammation. Membrane rafts are ordered assemblies of cholesterol, glycolipids, and proteins that modulate proinflammatory cell signaling and barrier function. In epithelial cells, the MAL family members MAL, MAL2, and myeloid-associated differentiation marker (MYADM) regulate the function and dynamics of ordered membrane domains. We analyzed the expression of these three proteins in human endothelial cells and found that only MYADM is expressed. MYADM was confined in ordered domains at the plasma membrane, where it partially colocalized with filamentous actin and cell–cell junctions. Small interfering RNA (siRNA)-mediated MYADM knockdown increased permeability, ICAM-1 expression, and leukocyte adhesion, all of which are features of an inflammatory response. Barrier function decrease in MYADM-silenced cells was dependent on ICAM-1 expression. Membrane domains and the underlying actin cytoskeleton can regulate each other and are connected by ezrin, radixin, and moesin (ERM) proteins. In endothelial cells, MYADM knockdown induced ERM activation. Triple-ERM knockdown partially inhibited ICAM-1 increase induced by MYADM siRNA. Importantly, ERM knockdown also reduced ICAM-1 expression in response to the proinflammatory cytokine tumor necrosis factor-α. MYADM therefore regulates the connection between the plasma membrane and the cortical cytoskeleton and so can control the endothelial inflammatory response.
Direct binding of the Kex2p cytosolic tail to the VHS domain of yeast Gga2p facilitates TGN to prevacuolar compartment transport and is regulated by phosphorylation
Authors: De Mithu , Abazeed Mohamed E. , Fuller Robert S.
Published: December 2012

Human Golgi-localized, γ-ear–containing, ADP-ribosylation factor–binding proteins (Ggas) bind directly to acidic dileucine sorting motifs in the cytosolic tails (C-tails) of intracellular receptors. Despite evidence for a role in recruiting ubiquitinated cargo, it remains unclear whether yeast Ggas also function by binding peptide-sorting signals directly. Two-hybrid analysis shows that the Gga1p and Gga2p Vps27, Hrs, Stam (VHS) domains both bind a site in the Kex2p C-tail and that the Gga2p VHS domain binds a site in the Vps10p C-tail. Binding requires deletion of an apparently autoinhibitory sequence in the Gga2p hinge. Ser780in the Kex2p C-tail is crucial for binding: an Ala substitution blocks but an Asp substitution permits binding. Biochemical assays using purified Gga2p VHS–GGA and TOM1 (GAT) and glutathione S-transferase–Kex2p C-tail fusions show that Gga2p binds directly to the Kex2p C-tail, with relative affinities Asp780> Ser780> Ala780. Affinity-purified antibody against a peptide containing phospho-Ser­780recognizes wild-type Kex2p but not S780A Kex2p, showing that Ser780is phosphorylated in vivo; phosphorylation of Ser780is up-regulated by cell wall–damaging drugs. Finally, mutation of Ser780alters trafficking of Kex2p both in vivo and in cell-free trans-Golgi network (TGN)–prevacuolar compartment (PVC) transport. Thus yeast Gga adaptors facilitate TGN–PVC transport by direct binding of noncanonical phosphoregulated Gga-binding sites in cargo molecules.
Effects of Intravascular Volume Replacement on Lung and Kidney Function and Damage in Nonseptic Experimental Lung Injury
Authors: Silva Pedro L. , Güldner Andreas , Uhlig Christopher , Carvalho Nadja , Beda Alessandro , Rentzsch Ines , Kasper Michael , Wiedemann Bärbel , Spieth Peter M. , Koch Thea , Capelozzi Vera L. , Pelosi Paolo , Rocco Patricia R. M. , de Abreu Marcelo Gama
Published: December 2012

Background:

Intravascular volume replacement is often required in the presence of increased pulmonary capillary leakage, for example in patients with volutrauma with major hemorrhage. In the present study, the effects of Ringer’s acetate (RA), gelatin-polysuccinate (GEL), and a modern hydroxyethyl starch (HES, 6% 130/0.42) on lung and kidney function and damage were compared in a two-hit model of acute lung injury. The authors hypothesized that GEL and HES, compared to RA: (1) reduced lung histological damage, (2) impaired kidney morphology and function.

Methods:

Acute lung injury was induced in 30 anesthetized pigs by tidal volumes approximately 40 ml/kg, after saline lung lavage. Protective ventilation was initiated and approximately≈25% of estimated blood volume was drawn. Animals were randomly assigned to receive RA, GEL, or HES (n = 10/group) aimed at approximately 90% of intrathoracic blood volume before blood drainage.

Results:

Fluid volumes were higher with RA (2,250 ± 764 ml) than GEL (704 ± 159 ml) and HES (837 ± 82 ml) (P < 0.05). Compared to RA, HES reduced diffuse alveolar damage overall, and GEL in nondependent zones only. GEL and HES yielded lower wet-to-dry ratios compared to RA (6.5 ± 0.5 and 6.5 ± 0.6 vs. 7.9 ± 0.9, respectively, P < 0.05). HES and RA resulted in less kidney damage than GEL, but kidney function did not differ significantly among groups. Compared to GEL, HES yielded lower lung elastance (55 ± 12 vs. 45 ± 13 cm H2O/l, P < 0.05) and intra-abdominal pressure (15 ± 5 vs. 11 ± 4 cm 14;H2O, P < 0.05).

Conclusions:

In this model of acute lung injury, intravascular volume expansion after major hemorrhage with HES yielded less lung damage than RA and less kidney damage than GEL.
International Incidence and Outcomes of Biliary Atresia
Authors: Jimenez‐Rivera Carolina , Jolin‐Dahel Kheira S. , Fortinsky Kyle J. , Gozdyra Peter , Benchimol Eric I.
Published: December 2012

Objectives:

International trends in incidence and outcomes of biliary atresia (BA) are controversial and a wide range of estimates have been reported worldwide. We reviewed the population‐based literature to assess international variation of BA incidence and outcomes, and to assess the evidence for seasonal variation in incidence, centralization of Kasai hepatoportoenterostomy, and newborn screening.

Methods:

We conducted a systematic review (registration number CRD42011001441) of observational or interventional research within MEDLINE, EMBASE, and the Cochrane Database, which reported incidence, prevalence, or outcomes of infants with BA. Population‐based studies, defined by inclusion of an entire population or representative sample, were included. Outcomes included overall survival, native liver survival (NLS), and time to Kasai hepatoportoenterostomy. Single‐ or multicenter studies were excluded unless those centers captured all potential patients within a jurisdiction. Two independent data extractors reviewed the abstracts and articles.

Results:

A total of 40 studies were included following review of 3128 references. A wide range of incidence was reported internationally. Ten‐year overall survival ranged from 66.7% to 89%. NLS ranged from 20.3% to 75.8% at 1 to 3 years and 24% to 52.8% at 10 years. Earlier age at Kasai was a predictor of improved NLS. Seasonality was reported in 11 studies, and 3 reported an increased incidence during the months of August to March. The evidence for centralization of Kasai to high‐volume centers is promising but does not account for all case‐mix, provider, or health system factors involved in volume–outcome relations. Stool color card screening resulted in earlier Kasai and improved NLS in Taiwan.

Conclusions:

Large, international studies could help fill the gaps in knowledge identified by this review.