bluuebunny/crossref_metadata_2025 huggingface dataset:
Non-silicide Schottky barrier p-type tunnel FET with a gate-around-drain structure formed by a junctionless FET process
Authors: Fang Yung-Chin , Hsieh Ching-Heng , Sun Cherng-En , Wu Yung-Hsien
Published: May 2015

P-type Schottky barrier based tunnel FET with gate-around-drain structure formed by junctionless FET process.
Learning with and about advertising in chemistry education with a lesson plan on natural cosmetics – a case study
Authors: Belova Nadja , Eilks Ingo
Published: May 2015

This paper describes a case study on the chemistry behind natural cosmetics in five chemistry learning groups (grades 7–11, age range 13–17) in a German comprehensive school. The lesson plan intends to promote critical media literacy in the chemistry classroom and specifically emphasizes learning with and about advertising. The lessons of four lesson periods encompass several strategies for evaluating and creating advertising. Evaluation was carried out using a questionnaire with both open-ended and Likert-type questions. Classroom observation protocols were also analyzed. The lesson plan proved to be very motivating and it initiated intense discussion about chemistry and science-related information in advertising. The findings of this study indicate that the lessons triggered self-reflection on students' consumer behavior. Most of the younger pupils saw advertising as a suitable and important topic for the science classroom. More advanced students tended to regard such issues as an interesting, but in some cases an unnecessary, part of their science education. Findings from the different groups are compared. Future research directions are also considered.
Tensile properties and in vitro degradation of P(TMC-co-LLA) elastomers
Authors: Cork Jorja , Whittaker Andrew K. , Cooper-White Justin J. , Grøndahl Lisbeth
Published: May 2015

The degradation mechanism of P(TMC-co-LLA) films was dependent on the LLA content and found to transition from heterogeneous to homogeneous bulk degradation.
A hematite-based photoelectrochemical platform for visible light-induced biosensing
Authors: Ryu Gyeong Min , Lee Minah , Choi Da Som , Park Chan Beum
Published: May 2015

The first hematite-based PEC biosensor platform is developed and applied for the detection of NADH under visible-light irradiation.
Variation in Vowel Duration Among Southern African American English Speakers
Authors: Holt Yolanda Feimster , Jacewicz Ewa , Fox Robert Allen
Published: May 2015

Purpose

Atypical duration of speech segments can signal a speech disorder. In this study, we examined variation in vowel duration in African American English (AAE) relative to White American English (WAE) speakers living in the same dialect region in the South to characterize the nature of systematic variation between the 2 groups. The goal was to establish whether segmental durations in minority populations differ from the well-established patterns in mainstream populations.

Method

Participants were 32 AAE and 32 WAE speakers differing in age who, in their childhood, attended either segregated (older speakers) or integrated (younger speakers) public schools. Speech materials consisted of 14 vowels produced in
hVd
-frame.

Results

AAE vowels were significantly longer than WAE vowels. Vowel duration did not differ as a function of age. The temporal tense–lax contrast was minimized for AAE relative to WAE. Vowels produced by females were significantly longer than vowels produced by males for both AAE and WAE.

Conclusions

African American speakers should be expected to produce longer vowels relative to White speakers in a common geographic area. These longer durations are not deviant but represent a typical feature of AAE. This finding has clinical importance in guiding assessments of speech disorders in AAE speakers.
Non‐linear set‐membership identification approach based on the Bayesian framework
Authors: Fernández‐Cantí Rosa M. , Tornil‐Sin Sebastian , Blesa Joaquim , Puig Vicenç
Published: May 2015

This study deals with the problem of set‐membership identification of non‐linear‐in‐the‐parameters models. To solve this problem, this study illustrates how the Bayesian approach can be used to determine the feasible parameter set (FPS) by assuming uniform distributed estimation error and flat model prior probability distributions. The key point of the methodology is the interval evaluation of the likelihood function and the result is a set of boxes with associated credibility indices. For each box, the credibility index is in the interval (0, 1] and gives information about the amount of consistent models inside the box. The union of the boxes with credibility value equal to one provides an inner approximation of the FPS, whereas the union of all boxes provides an outer estimation. The boxes with credibility value smaller than one are located around the boundary of the FPS and their credibility index can be used to iteratively refine the inner and outer approximations up to a desired precision. The main issues and performance of the developed algorithms are discussed and illustrated by means of examples.
Lyapunov–Krasovskii functionals for input‐to‐state stability of switched non‐linear systems with time‐varying input delay
Authors: Wang Yue‐E , Sun Xi‐Ming , Wu Baowei
Published: May 2015

This study investigates the input‐to‐state stability issue and the Lyapunov–Krasovskii functional construction for a class of switched non‐linear systems with time‐varying input delay under mode‐dependent average dwell‐time scheme. The authors assume that an exponential stabilising state feedback controller has been predesigned for the nominal system and the Lyapunov function for the nominal closed‐loop system is available. When input delay and disturbance are involved, the closed‐loop system may be unstable under the average dwell time for the nominal system. In allusion to this instance, by introducing a positive definite relaxation matrix and constructing a novel piecewise Lyapunov–Krasovskii functional based on the known Lyapunov function, they provide sufficient conditions and the upper bound of the input delay such that the closed‐loop system is input‐to‐state stable with respect to the disturbance. Finally, numerical examples are given to illustrate the effective of the proposed method.
Stability of composite thermodynamic systems with interconnection constraints
Authors: Gromov Dmitry , Caines Peter E.
Published: May 2015

In this study, a formulation of thermodynamic systems in terms of contact geometry is proposed. Furthermore, a systematic approach to the description and analysis of composite thermodynamic systems, that is, systems containing a number of interacting thermodynamic subsystems, is developed. In such systems, there are always heat, work or matter flows between the subsystems which, together with constructive restrictions, form the interconnection structure of the composite system. This structure can be described by a set of constraints imposed on the system. In geometric terms, this can be seen as a restriction of the system space to a certain ‘constraint sub‐manifold’. Moreover, there are kinematic (non‐holonomic) constraints which restrict the system's dynamics while imposing no restrictions on the system configuration. Both geometric and kinematic constraints and their influence on the dynamics of the composite system are discussed. Finally, several types of composite thermodynamic system are presented and the LaSalle Invariance Principle is used to analyse the asymptotic dynamical behaviour of one important example.
Mechanism insight into the effect of I/P buffer layer on the performance of NIP-type hydrogenated microcrystalline silicon solar cells
Authors: Bai Lisha , Liu Bofei , Zhao Jing , Suo Song , Hou Guofu , Zhang Dekun , Sun Jian , Wei Changchun , Zhao Ying , Zhang Xiaodan
Published: May 2015

A simulation and experimental study on the effect of the buffer layer at the I/P interface on the performance of NIP-type hydrogenated microcrystalline silicon (μc-Si:H) single-junction solar cells is presented. Device-quality hydrogenated amorphous silicon (a-Si:H) material as a buffer layer at the I/P interface obviously improves the performance of NIP-type μc-Si:H single-junction solar cells. In addition to the well-known mechanism that an a-Si:H I/P buffer layer can reduce the recombination current density at I/P interfaces, the optically and electrically calibrated simulations and supporting experimental results in this study illustrate that the performance improvement also originates from the mitigation of the electric screening effect due to the reduced defect density at the I/P interfaces, which reinforces the bulk electric field. Integrating an optimized hydrogen profiling strategy and adding a-Si:H I/P buffer layer yielded an initial efficiency of 9.20% for μc-Si:H single-junction solar cells with an active area of 0.27 cm2. This study may provide new ideas of further improving the performance of NIP-type μc-Si:H single-junction solar cells by mitigating the electric screening effect.
The conductivity mechanism and an improved C−V model of ferroelectric PZT thin film
Authors: Liang K. , Buditama A. , Chien D. , Cui J. , Cheung P. L. , Goljahi S. , Tolbert S. H. , Chang J. P. , Lynch C. S.
Published: May 2015

A dense, homogeneous and crack-free ferroelectric PZT thin film with 〈100〉-preferred orientation was produced using the sol-gel method. The volume fraction α(100) of 〈100〉-oriented grains in the PZT film was calculated [α(100) ≈ 80%] from XRD of the PZT thin film and powder. The PZT thin film exhibits an open polarization vs. electric field loop and a low leakage current density from 10−8 A/cm2 to 10−7 A/cm2. The electrical conduction data were fit to a Schottky-emission model with deep traps from 100 kV/cm to 250 kV/cm. A modified capacitance model was introduced that adds electrical domain capacitance based on a metal-ferroelectric-metal (MFM) system with Schottky contacts. The model reproduces the observed non-linear capacitance vs. voltage behavior of the film.
On the rupture of DNA molecule
Authors: Mishra R. K. , Modi T. , Giri D. , Kumar S.
Published: May 2015

Using Langevin dynamics simulations, we study effects of the shear force on the rupture of a double stranded DNA molecule. The model studied here contains two single diblock copolymers interacting with each other. The elastic constants of individual segments of diblock copolymer are considered to be different. We showed that the magnitude of the rupture force depends on whether the force is applied at 3′ − 3′ − ends or 5′ − 5′ − ends. Distributions of extension in hydrogen bonds and covalent bonds along the chain show the striking differences. Motivated by recent experiments, we have also calculated the variation of rupture force for different chain lengths. Results obtained from simulations have been validated with the analytical calculation based on the ladder model of DNA.
A molecular dynamics investigation of the planar elongational rheology of chemically identical dendrimer-linear polymer blends
Authors: Hajizadeh Elnaz , Todd B. D. , Daivis P. J.
Published: May 2015

The structure and rheology of model polymer blends under planar elongational flow have been investigated through nonequilibrium molecular dynamics simulations. The polymeric blends consist of linear polymer chains (187 monomers per chain) and dendrimer polymers of generations g = 1 − 4. The number fraction, x, of the dendrimer species is varied (4%, 8%, and 12%) in the blend melt. We study the effect of extension rate, dendrimer generation, and dendrimer number fraction on pair distribution functions for different blend systems. We also calculate the extension-rate dependent radius of gyration and ratios of the eigenvalues of the gyration tensor to study the elongation-induced deformation of the molecules in the blend. Melt rheological properties including the first and second extensional viscosities are found to fall into the range between those of pure dendrimer and pure linear polymer melts, which are correlated with the mass fraction and generation of the dendrimers in the blend.
Measuring correlated electronic and vibrational spectral dynamics using line shapes in two-dimensional electronic-vibrational spectroscopy
Authors: Lewis Nicholas H. C. , Dong Hui , Oliver Thomas A. A. , Fleming Graham R.
Published: May 2015

Two-dimensional electronic-vibrational (2DEV) spectroscopy is an experimental technique that shows great promise in its ability to provide detailed information concerning the interactions between the electronic and vibrational degrees of freedom in molecular systems. The physical quantities 2DEV is particularly suited for measuring have not yet been fully determined, nor how these effects manifest in the spectra. In this work, we investigate the use of the center line slope of a peak in a 2DEV spectrum as a measure of both the dynamic and static correlations between the electronic and vibrational states of a dye molecule in solution. We show how this center line slope is directly related to the solvation correlation function for the vibrational degrees of freedom. We also demonstrate how the strength with which the vibration on the electronic excited state couples to its bath can be extracted from a set of 2DEV spectra. These analytical techniques are then applied to experimental data from the laser dye 3,3′-diethylthiatricarbocyanine iodide in deuterated chloroform, where we determine the lifetime of the correlation between the electronic transition frequency and the transition frequency for the backbone C = C stretch mode to be ∼1.7 ps. Furthermore, we find that on the electronic excited state, this mode couples to the bath ∼1.5 times more strongly than on the electronic ground state.
Negative permittivity behavior of aligned carbon nanotube films
Authors: Zhang Wei , Xiong Huagang , Wang Shaokai , Li Min , Gu Yizhuo
Published: May 2015

This paper reports a negative permittivity of aligned carbon nanotube (CNT) film materials by mechanical stretching. A CNT laminate with five layers of aligned CNT film exhibited unique negative permittivity, which was measured with waveguide method. Based on the microscopic morphology of aligned CNTs, a structure model from classical periodic array was introduced to describe the CNT arrangement and investigate the negative permittivity behavior of aligned CNT film. The influences of film's electrical conductivity, radius of CNT bundle, and lattice constant of aligned CNT assembly on real part of permittivity were discussed. Both experimental and simulation results indicate that the negative permittivity of aligned CNT film is closely related to its stretching ratio. The real part of permittivity drops below zero when stretching ratio reaches a certain level, which is about 15% stretching ratio in our experiment, and then it keeps decreasing with increasing stretching ratio.
Oersted field assisted magnetization reversal in cylindrical core-shell nanostructures
Authors: Otálora J. A. , Cortés-Ortuño D. , Görlitz D. , Nielsch K. , Landeros P.
Published: May 2015

A method to manipulate magnetization reversal in core-shell nanostructures is presented. The focus is on cylindrical multilayer structures comprising of an inner conductor wire covered by two shells: (i) an intermediate non-conducting and non-magnetic shell and (ii) a nanotube made of an outer ferromagnetic layer. The properties of the magnetization reversal of the ferromagnetic phase are investigated when a circular Oersted field is generated by applying an electric current through the inner wire. Coercive fields and remanent magnetization as functions of the circular field strength are explored. By means of a simple analytical model and OOMMF simulations, once the current is turned on, two key results have been found: (i) A manipulable axial demagnetization, that is, a magnetization transition from the quasi uniform alignment to a flux closure circular configuration when the circular field strength is above a critical field; and (ii) a quadratic reduction of the coercivity on the circular field strength, in the case that the nanotube magnetization is switched by an applied magnetic field along the tube axis and further assisted by a circular Oersted field. It is found that in this kind of structures, Oersted field assisted magnetization reversal (OAMR) can be an alternative way to reduce coercivity, as required by the magnetic storage industry and currently performed with heat assisted techniques.
Tests of the modified Sigmund model of ion sputtering using Monte Carlo simulations
Authors: Hofsäss Hans , Bradley R. Mark
Published: May 2015

Monte Carlo simulations are used to evaluate the Modified Sigmund Model of Sputtering. Simulations were carried out for a range of ion incidence angles and surface curvatures for different ion species, ion energies, and target materials. Sputter yields, moments of erosive crater functions, and the fraction of backscattered energy were determined. In accordance with the Modified Sigmund Model of Sputtering, we find that for sufficiently large incidence angles θ the curvature dependence of the erosion crater function tends to destabilize the solid surface along the projected direction of the incident ions. For the perpendicular direction, however, the curvature dependence always leads to a stabilizing contribution. The simulation results also show that, for larger values of θ, a significant fraction of the ions is backscattered, carrying off a substantial amount of the incident ion energy. This provides support for the basic idea behind the Modified Sigmund Model of Sputtering: that the incidence angle θ should be replaced by a larger angle Ψ to account for the reduced energy that is deposited in the solid for larger values of θ.
Phase-mixing of ion plasma modes in pair-ion plasmas
Authors: Pramanik Sourav , Maity Chandan , Chakrabarti Nikhil
Published: May 2015

Nonlinear interaction between two electrostatic normal modes of a warm pair-ion plasma, viz., ion plasma mode (Langmuir mode) and ion acoustic mode has been analyzed by employing a perturbation technique. It is shown that a gradual loss of phase coherence in the excited Langmuir wave dynamics (phase-mixing) occurs in such a plasma, leading to wave-breaking at arbitrarily low wave amplitudes. Nonlinear results provide an approximate expression for the phase-mixing time which is found to increase with the increase of the ratio of acoustic frequency to Langmuir frequency. The results of our investigation are expected to be relevant to the laboratory produced paired fullerene-ion plasmas.
Note: Measuring capacitance and inductance of a helical resonator and improving its quality factor by mutual inductance alteration
Authors: Panja S. , De S. , Yadav S. , Sen Gupta A.
Published: May 2015

Narrow bandwidth and high voltage radio frequency (RF) is an essential requirement for stable confinement of ions within a RF trap and helical resonators are commonly used for that purpose. Effective capacitance and inductance of a helical resonator are estimated by measuring resonant frequencies for different external loads. Load capacitance of an ion trap can be estimated from this method and a resonator can be constructed for desired resonant frequency. We demonstrate a very simple method to achieve higher Q-factor of a resonator by optimizing mutual separation between the primary antenna and helical coil. We also formulate a set of analytical equations for calculating overall inductance, resistance, and Q-factor of a loaded helical resonator.
Boiling on spatially controlled heterogeneous surfaces: Wettability patterns on microstructures
Authors: Jo HangJin , Yu Dong In , Noh Hyunwoo , Park Hyun Sun , Kim Moo Hwan
Published: May 2015

We investigated nucleate boiling heat transfer with precisely controlled wetting patterns and micro-posts, to gain insights into the impact of surface heterogeneity. To create heterogeneous wetting patterns, self-assembled monolayers (SAMs) were spatially patterned. Even at a contact angle <90°, bubble nucleation and bubble frequency were accelerated on SAM patterns, since this contact angle is larger than that found on plain surfaces. Micro-posts were also fabricated on the surface, which interrupted the expansion of generated bubbles. This surface structuring induced smaller bubbles and higher bubble frequency than the plain surface. The resistance provided by surface structures to bubble expansion broke the interface between the vapor mushroom and the heating surface, and water could therefore be continuously supplied through these spaces at high heat flux. To induce synergistic effects with wetting patterns and surface structures on boiling, we fabricated SAM patterns onto the heads of micro-posts. On this combined surface, bubble nucleation was induced from the head of the micro-posts, and bubble growth was influenced by both the SAM pattern and the micro-post structures. In particular, separation of the vapor path on the SAM patterns and the liquid path between micro-post structures resulted in high heat transfer performance without critical heat flux deterioration.
Graphite edge controlled registration of monolayer MoS2 crystal orientation
Authors: Lu Chun-I , Butler Christopher John , Huang Jing-Kai , Hsing Cheng-Rong , Yang Hung-Hsiang , Chu Yu-Hsun , Luo Chi-Hung , Sun Yung-Che , Hsu Shih-Hao , Yang Kui-Hong Ou , Wei Ching-Ming , Li Lain-Jong , Lin Minn-Tsong
Published: May 2015

Transition metal dichalcogenides such as the semiconductor MoS2 are a class of two-dimensional crystals. The surface morphology and quality of MoS2 grown by chemical vapor deposition are examined using atomic force and scanning tunneling microscopy techniques. By analyzing the moiré patterns from several triangular MoS2 islands, we find that there exist at least five different superstructures and that the relative rotational angles between the MoS2 adlayer and graphite substrate lattices are typically less than 3°. We conclude that since MoS2 grows at graphite step-edges, it is the edge structure which controls the orientation of the islands, with those growing from zig-zag (or armchair) edges tending to orient with one lattice vector parallel (perpendicular) to the step-edge.
H-point exciton transitions in bulk MoS2
Authors: Saigal Nihit , Ghosh Sandip
Published: May 2015

Reflectance and photoreflectance spectrum of bulk MoS2 around its direct bandgap energy have been measured at 12 K. Apart from spectral features due to the A and B ground state exciton transitions at the K-point of the Brillouin zone, one observes additional features at nearby energies. Through lineshape analysis the character of two prominent additional features are shown to be quite different from that of A and B. By comparing with reported electronic band structure calculations, these two additional features are identified as ground state exciton transitions at the H-point of the Brillouin zone involving two spin-orbit split valance bands. The excitonic energy gap at the H-point is 1.965 eV with a valance bands splitting of 185 meV. While at the K-point, the corresponding values are 1.920 eV and 205 meV, respectively.
Spin-current diode with a ferromagnetic semiconductor
Authors: Sun Qing-Feng , Xie X. C.
Published: May 2015

Diode is a key device in electronics: the charge current can flow through the device under a forward bias, while almost no current flows under a reverse bias. Here, we propose a corresponding device in spintronics: the spin-current diode, in which the forward spin current is large but the reversed one is negligible. We show that the lead/ferromagnetic quantum dot/lead system and the lead/ferromagnetic semiconductor/lead junction can work as spin-current diodes. The spin-current diode, a low dissipation device, may have important applications in spintronics, as the conventional charge-current diode does in electronics.
Effect of hot-carrier energy relaxation on main properties of collapsing field domains in avalanching GaAs
Authors: Palankovski V. , Vainshtein S. , Yuferev V. , Kostamovaara J. , Egorkin V.
Published: May 2015

Multiple “collapsing” field domains are a physical reason for superfast switching and sub-terahertz (sub-THz) emission experimentally observed in powerfully avalanching GaAs structures. This phenomenon, however, has been studied so far without considering carrier energy relaxation and that essentially has restricted the possibility of correct interpretation of experimental results. Here, we apply a hydrodynamic approach accounting for non-local hot-carrier effects. The results confirm the collapsing domain concept, but show that the domains cannot reduce well below 100 nm in width, since a moving collapsing domain leaves behind it a tail of hot carriers, which causes broadening in the rear wall of the domain. This puts principal restrictions on the emission band achievable with our unique avalanche mm-wave source to about 1 THz. Another finding suggested here is a physical mechanism for the single collapsing domain's quasi-steady-state motion determined by powerful impact ionization. The results are of significance for physical interpretation of properties of our pulsed sub-THz source, which has recently demonstrated its application potential in mm-wave imaging in both amplitude and time-domain pulse modes with picosecond time-of-flight precision.
Characterization of locally strained Ge1−xSnx/Ge fine structures by synchrotron X-ray microdiffraction
Authors: Ike Shinichi , Nakatsuka Osamu , Moriyama Yoshihiko , Kurosawa Masashi , Taoka Noriyuki , Imai Yasuhiko , Kimura Shigeru , Tezuka Tsutomu , Zaima Shigeaki
Published: May 2015

We have investigated the formation of the locally strained Ge nanostructure with epitaxial Ge1−xSnx stressors and characterized the microscopic strain field in the Ge1−xSnx/Ge fine-heterostructures by synchrotron X-ray microdiffraction and finite element method (FEM) calculations. We achieved local epitaxial growth of Ge1−xSnx with Sn contents of 2.9% and 6.5%, sandwiching the 25 nm-wide Ge fine line structure. Microdiffraction measurements revealed that out-of-plane tensile strain induced in the Ge line effectively increased with decreasing Ge width and increasing Sn content of Ge1−xSnx stressors, which is in good agreement with FEM calculations. An out-of-plane tensile strain of 0.8% along the Ge[001] direction is induced in a 25 nm-wide Ge line, which corresponds to an in-plane uniaxial compressive strain of 1.4% in the Ge line sandwiched between Ge0.935Sn0.065 stressors.
Self-assembled peptide nanotubes as electronic materials: An evaluation from first-principles calculations
Authors: Akdim Brahim , Pachter Ruth , Naik Rajesh R.
Published: May 2015

In this letter, we report on the evaluation of diphenylalanine (FF), dityrosine (YY), and phenylalanine-tryptophan (FW) self-assembled peptide nanotube structures for electronics and photonics applications. Realistic bulk peptide nanotube material models were used in density functional theory calculations to mimic the well-ordered tubular nanostructures. Importantly, validated functionals were applied, specifically by using a London dispersion correction to model intertube interactions and a range-separated hybrid functional for accurate bandgap calculations. Bandgaps were found consistent with available experimental data for FF, and also corroborate the higher conductance reported for FW in comparison to FF peptide nanotubes. Interestingly, the predicted bandgap for the YY tubular nanostructure was found to be slightly higher than that of FW, suggesting higher conductance as well. In addition, the band structure calculations along the high symmetry line of nanotube axis revealed a direct bandgap for FF. The results enhance our understanding of the electronic properties of these material systems and will pave the way into their application in devices.
Magnetoelectrets prepared by using temperature gradient method
Authors: Ojha Pragya , Qureshi M.S , Malik M.M
Published: May 2015

A novel Temperature Gradient method for preparation of magnetoelectret is proposed. Non uniform magnetic field and temperature gradient are expected to be the main cause for the formation of magnetoelectrets (MEs). Being bad conductors of heat, during their formation, there is a possibility for the existence of a temperature gradient along the dielectric electrode interface. In this condition, the motion of, molecules and charge carriers are dependent on Temperature Gradient in a preferred direction. To increase this temperature gradient on both sides of the sample novel method for the preparation of MEs is developed for the first time. For this method the special sample holders are designed in our laboratory. MEs are prepared in such a way that one surface is cooled and the other is heated, during the process. With the help of XRD analysis using Type-E orientation pattern and surface charge studies on magnetoelectrets, the two main causes Non uniform magnetic field and temperature gradient for the formation of magnetoelectrets (MEs), are authenticated experimentally.
Ecotypic differentiation of mid-Atlantic Quercus species in response to ultramafic soils
Authors: Burgess Jerry , Szlavecz Katalin , Rajakaruna Nishanta , Swan Christopher
Published: May 2015

Spatial heterogeneity of soil conditions combined with intraspecific variation confer site-specific edaphic tolerance, resulting in local adaptation and speciation. To understand the geoecological processes controlling community assembly of woodland tree species on serpentine and mafic soils, we investigated resource gradients and provenance (geographic area of propagule collection) as variables affecting typical representative upland oak (Quercus) species distribution. Accordingly, we conducted a year-long reciprocal transplant experiment in the greenhouse with serpentine and mafic soils, using seedlings of five oak species (Quercus marilandica, Q. stellata, Q. montana, Q. michauxii and Q. alba). All seedlings, regardless of provenance or soil depth, displayed more robust growth in the mafic soils. Soil depth was an important determinant, with all species exhibiting increased growth in the deeper-soil treatments. Fitness surrogates such as stem height, relative growth rate, and leaves per plant were greater when seedlings were grown in their home soil than when they were grown in the non-resident soil, suggesting an ecotypic effect. Mean stomatal conductance and stem growth were positively correlated with soil depth in all treatments. Taken together, the study showed provenance-specific growth responses of oak seedlings to soil type and depth, providing a better understanding of the mechanisms controlling species assembly in woodland communities.
Shifts in shell mineralogy and metabolism of Concholepas concholepas juveniles along the Chilean coast
Authors: Ramajo Laura , Rodríguez-Navarro Alejandro B. , Duarte Carlos M. , Lardies Marco A. , Lagos Nelson A.
Published: May 2015

Along the west coast of South America, from the tropical zone to the Patagonian waters, there is a significant latitudinal gradient in seawater temperature, salinity and carbonate chemistry. These physical–chemical changes in seawater induce morphological and physiological responses in calcifying organisms, which may alter their energy budget and calcification processes. In this study, we study the organism energy maintenance (i.e. metabolic rate) and mineralogical composition of the shell of the juvenile marine snails Concholepas concholepas (Gastropoda: Muricidae), collected from benthic populations located ~2000km apart, varies across geographic regions along the Chilean coast. We found that in juvenile snails, the calcite:aragonite ratio in the pallial shell margin (i.e. newly deposited shell) increase significantly from northern to southern populations and this increase in calcite precipitation in the shell of juveniles snails was associated with a decrease in oxygen consumption rates in these populations. Our result suggests that calcite secretion may be favoured when metabolic rates are lowered, as this carbonate mineral phase might be less energetically costly for the organism to precipitate. This result is discussed in relation to the natural process such as coastal upwelling and freshwater inputs that promote geographic variation in levels of pH and carbonate saturation state in seawater along the Chilean coast.
Connectivity reveals relationship of brain areas for reward-guided learning and decision making in human and monkey frontal cortex
Authors: Neubert Franz-Xaver , Mars Rogier B. , Sallet Jérôme , Rushworth Matthew F. S.
Published: May 2015

Significance

Because of the interest in reward-guided learning and decision making, these neural mechanisms have been studied in both humans and monkeys. But whether and how key brain areas correspond between the two species has been uncertain. Areas in the two species can be compared as a function of the brain circuits in which they participate, which can be estimated from patterns of correlation in brain activity measured with functional MRI. Taking such measurements in 38 humans and 25 macaques, we identified fundamental similarities between the species and one human frontal area with no monkey counterpart. Altogether these findings suggest that everyday human decision-making capitalizes on a neural apparatus similar to the one that supports monkeys when foraging in the wild.
Modulation of extrasynaptic NMDA receptors by synaptic and tonic zinc
Authors: Anderson Charles T. , Radford Robert J. , Zastrow Melissa L. , Zhang Daniel Y. , Apfel Ulf-Peter , Lippard Stephen J. , Tzounopoulos Thanos
Published: May 2015

Significance

As an essential element for living organisms, zinc is a cofactor in many enzymes and regulatory proteins. After the surprising discovery of mobile zinc in synaptic vesicles throughout many areas of the brain, numerous investigators have studied its possible roles during neurotransmission. Nonetheless, knowledge of the physiology of zinc at the synapse is still in its infancy. Here, we show that synaptic and tonic zinc inhibit extrasynaptic NMDA receptors (NMDARs), which are widely distributed in the CNS and are important for normal and pathological excitatory signaling. Our work indicates that this newly discovered interaction between zinc and extrasynaptic NMDARs can provide a general mechanism for controlling neuronal excitability in the CNS.
Proliferation-dependent positioning of individual centromeres in the interphase nucleus of human lymphoblastoid cell lines
Authors: Ollion Jean , Loll François , Cochennec Julien , Boudier Thomas , Escudé Christophe
Published: May 2015

The cell nucleus is a highly organized structure and plays an important role in gene regulation. Understanding the mechanisms that sustain this organization is therefore essential for understanding genome function. Centromeric regions (CRs) of chromosomes have been known for years to adopt specific nuclear positioning patterns, but the significance of this observation is not yet completely understood. Here, using a combination of fluorescence in situ hybridization and immunochemistry on fixed human cells and high-throughput imaging, we directly and quantitatively investigated the nuclear positioning of specific human CRs. We observe differential attraction of individual CRs toward both the nuclear border and the nucleoli, the former being enhanced in nonproliferating cells and the latter being enhanced in proliferating cells. Similar positioning patterns are observed in two different lymphoblastoid cell lines. Moreover, the positioning of CRs differs from that of noncentromeric regions, and CRs display specific orientations within chromosome territories. These results suggest the existence of not-yet-characterized mechanisms that drive the nuclear positioning of CRs and therefore pave the way toward a better understanding of how CRs affect nuclear organization.
Synergistic interaction between the fibroblast growth factor and bone morphogenetic protein signaling pathways in lens cells
Authors: Boswell Bruce A. , Musil Linda S.
Published: May 2015

Fibroblast growth factors (FGFs) play a central role in two processes essential for lens transparency—fiber cell differentiation and gap junction–mediated intercellular communication (GJIC). Using serum-free primary cultures of chick lens epithelial cells (DCDMLs), we investigated how the FGF and bone morphogenetic protein (BMP) signaling pathways positively cooperate to regulate lens development and function. We found that culturing DCDMLs for 6 d with the BMP blocker noggin inhibits the canonical FGF-to-ERK pathway upstream of FRS2 activation and also prevents FGF from stimulating FRS2- and ERK-independent gene expression, indicating that BMP signaling is required at the level of FGF receptors. Other experiments revealed a second type of BMP/FGF interaction by which FGF promotes expression of BMP target genes as well as of BMP4. Together these studies reveal a novel mode of cooperation between the FGF and BMP pathways in which BMP keeps lens cells in an optimally FGF-responsive state and, reciprocally, FGF enhances BMP-mediated gene expression. This interaction provides a mechanistic explanation for why disruption of either FGF or BMP signaling in the lens leads to defects in lens development and function.
A multilingual gold-standard corpus for biomedical concept recognition: the Mantra GSC
Authors: Kors Jan A , Clematide Simon , Akhondi Saber A , van Mulligen Erik M , Rebholz-Schuhmann Dietrich
Published: May 2015

Objective To create a multilingual gold-standard corpus for biomedical concept recognition.

Materials and methods We selected text units from different parallel corpora (Medline abstract titles, drug labels, biomedical patent claims) in English, French, German, Spanish, and Dutch. Three annotators per language independently annotated the biomedical concepts, based on a subset of the Unified Medical Language System and covering a wide range of semantic groups. To reduce the annotation workload, automatically generated preannotations were provided. Individual annotations were automatically harmonized and then adjudicated, and cross-language consistency checks were carried out to arrive at the final annotations.

Results The number of final annotations was 5530. Inter-annotator agreement scores indicate good agreement (median F-score 0.79), and are similar to those between individual annotators and the gold standard. The automatically generated harmonized annotation set for each language performed equally well as the best annotator for that language.

Discussion The use of automatic preannotations, harmonized annotations, and parallel corpora helped to keep the manual annotation efforts manageable. The inter-annotator agreement scores provide a reference standard for gauging the performance of automatic annotation techniques.

Conclusion To our knowledge, this is the first gold-standard corpus for biomedical concept recognition in languages other than English. Other distinguishing features are the wide variety of semantic groups that are being covered, and the diversity of text genres that were annotated.
Interrupting Coercion
Authors: Forgatch Marion S. , Domenech Rodríguez Melanie M.
Published: May 2015

The Oregon Model of Parent Management Training (PMTO) is an intervention based on the social interaction learning model, which posits coercion as a disruptor for family processes and outcomes. This chapter examines the role that coercion plays in the context of theory-based intervention, reviewing two randomized, controlled trials that evaluated coercive and positive parenting practices as mediators of outcomes. The studies examined the differential effects of changes on coercive and positive parenting as well as the orderly sequence of these changes and their mediating effects in short-term and longer term follow-up data. The chapter considers family contextual factors and their impact on change processes during intervention and includes a discussion of factors such as parental adjustment (depression, antisocial qualities) and stressful circumstances and their relationship to parental resistance during intervention. Practitioner variables and practices are examined as contributors to the change process. Some findings of resistance observed during therapy are discussed.
Changing Parental Perspectives of Coercion Dynamics
Authors: Smith Justin D.
Published: May 2015

This chapter considers video feedback as an intervention strategy for managing parent-child coercion dynamics and associated child behavior problems during the early childhood period. It begins with a discussion of parent-child interactions and the coercive interpersonal dynamic between children and their parents. It then reviews the evidence base for the effectiveness of various interventions in early childhood, together with the theoretical and empirical rationale for videotaped feedback interventions. It also examines caregivers’ relational schemas in the context of parent-child interactions before concluding with an explanation of how to deliver video feedback interventions effectively. The Family Check-Up program is used to illustrate the way in which a brief video feedback intervention can be integrated within existing family-focused intervention protocols.
Tip-of-the-Tongue States, Déjà Vu Experiences, and Other Odd Metacognitive Experiences
Authors: Schwartz Bennett L. , Cleary Anne M.
Published: May 2015

This chapter discusses several forms of metamemory hiccups—subjective experiences that alert us to potential conflict between our metacognitive state and our memory capabilities at the moment; for example, tip-of-the-tongue states, déjà vu experiences, and blank-in-the-mind states. These states occur when we set out to accomplish a task but find ourselves with the will to complete a task but unable to recall what that task was. This chapter describes these phenomena, the research on their causes and consequences, and why they are important to our understanding of metamemory in general. These experiences can prompt us to attempt to resolve these discrepancies through metacognitive control, such as by directing attention toward information-gathering or retrieval efforts. By alerting us that something is amiss, such experiences act as early-warning systems, allowing us to monitor and control our own mental processes.
Work–Family Issues in Family Business
Authors: Pieper Torsten , Astrachan Joseph H. , Neglia John
Published: May 2015

This chapter discusses work–family issues in family business, a particular type of work arrangement not commonly studied in the traditional work–family literature. Specifically, unlike in nonfamily business settings, family influence permeates the organization, including within employee, management, and ownership realms. Another characteristic worthy of study is that family firms have work–family conflict among family owner employees as well as typical nonowner employees often leading to heightened emotions as well as more relaxed work–family interface policies. The purpose of this chapter is to describe the particularities of family businesses with regard to both positive and negative work–family and family–work conflicts, explain some of the underlying dynamics, and point out potential avenues for future studies that might be of interest to work–family and family business researchers.
Work, Family, and Employee Health
Authors: Grzywacz Joseph
Published: May 2015

Evidence and initiatives suggest that everyday work and family life may shape human health. Unfortunately, this literature remains theoretically underdeveloped and methodologically speculative. This chapter is designed to equip researchers to design and implement effective translational research focused on work and family and employee health. The chapter begins by illustrating the complexity of “health” and prioritizing the value of studying discrete aspects of health. The chapter then identifies three primary ways of thinking about “successful integration of work and family,” and it delineates four discrete hypotheses linking successful integration of work and family to health outcomes. This section includes a review of empirical evidence relevant to each hypothesis. The chapter concludes by identifying a high priority agenda for catapulting work, family, and health research forward.
Medical Illness, Suicide, and Assisted Death
Authors: Kleespies Phillip M.
Published: May 2015

Because of their focus on psychopathology, mental health clinicians may overlook the potential significance of medical illness as a risk factor for suicide. In this chapter, the author presents evidence that physical illness, particularly certain physical illnesses, can be independent risk factors for suicide. In a number of these illnesses, depression is clearly a confounding risk factor, while in others the illness itself or its consequent functional impairments may lead to increased risk. When an individual has multiple physical illnesses, as often happens with the elderly, the cumulative burden can become overwhelming and heighten the risk of suicide. When physical illness becomes terminal, the competent patient has the right to refuse life-sustaining treatment. Whether that individual can receive assistance in dying has been more controversial. The chapter concludes with a presentation of data from a state where assisted suicide, also known as assisted death, has been legalized.
Impact on Organizations
Authors: Smith Alexis , Simms Shalei
Published: May 2015

This chapter examines the organizational impact of discrimination. Through its effect on organizational personnel processes, unfair discrimination has far-reaching and long-lasting impact on individuals, groups, and the organization as a whole. The chapter reviews the multiple ways that discrimination can infect human resource practices and policies, which in turn negatively impacts organizational outcomes such as applicant attraction, employee well-being and retention, group and organizational performance, and firm reputation. It then turns to the role of organizational climate for diversity, which has a potentially mitigating effect on the impact of discrimination. It suggests that, through deliberate organizational learning, companies with positive climates for diversity have the capacity to use events of discrimination as a turning point toward sustained organizational change and growth. The chapter closes by exploring how organizations can create the conditions for this redemptive potential and, ultimately, learn from discrimination and prevent its reoccurrence.
Biological Markers of Substance Use
Authors: Snell Lawrence D. , Bhave Sanjiv V. , Takacs Laszlo , Tabakoff Boris
Published: May 2015

Ascertaining an individual’s history of alcohol consumption is an important component in the proper treatment of accidental trauma or acute or chronic illness, as well as for matters of public health and safety, legal issues, insurance coverage, and the management of and recovery from hazardous/harmful levels of alcohol consumption. Although self-report of alcohol consumption in both research and clinical settings represents the most common mode of assessment, there is long-standing interest in developing objective measures of alcohol consumption that do not rely on the ability or willingness of a person to truthfully report consumption. Biologic diagnostic tests or biomarkers can provide information on current and past quantity and frequency of alcohol consumption. This chapter discusses and evaluates many of the biomarker candidates that have been investigated and provides insights into future searches for optimal diagnostic tools to provide biologic evidence of duration, quantity, and frequency of individual alcohol consumption. We have included a limited discussion of biomarkers for assessing cannabis use since cannabis and alcohol use many times are a concomitant feature of intoxication.