bluuebunny/crossref_metadata_2025 huggingface dataset:
Nanoscale manipulation of Ge nanowires by ion irradiation
Authors: Romano Lucia , Rudawski Nicholas G. , Holzworth Monta R. , Jones Kevin S. , Choi S. G. , Picraux S. T.
Published: December 2009

Nanowires have generated considerable interest as nanoscale interconnects and as active components of both electronic and electromechanical devices. However, in many cases, manipulation and modification of nanowires are required to fully realize their potential. It is essential, for instance, to control the orientation and positioning of nanowires in some specific applications. This work demonstrates a simple method to reversibly control the shape and the orientation of Ge nanowires using ion beams. Crystalline nanowires were amorphized by 30 keV Ga+ implantation. Subsequently, viscous flow and plastic deformation occurred causing the nanowires to bend toward the beam direction. The bending was reversed multiple times by ion implanting the opposite side of the nanowires, resulting in straightening and subsequent bending into that opposite direction. This effect demonstrates the detailed manipulation of nanoscale structures is possible through the use of ion irradiation.
Inner-shell photoionization spectroscopy on deposited metal clusters using soft x-ray synchrotron radiation: An experimental setup
Authors: Peters S. , Peredkov S. , Balkaya B. , Ferretti N. , Savci A. , Vollmer A. , Neeb M. , Eberhardt W.
Published: December 2009

Exploration of mass-selected clusters by soft x-ray synchrotron radiation is well suited to receive element specific information on clusters in contact with a support and to systematically follow the evolution of size-dependent electronic and geometrical properties from the smallest clusters toward the bulk. Here we describe an experimental setup, which combines cluster synthesis, mass selection, soft landing, ultrahigh vacuum transfer, and photoionization experiments such as x-ray photoelectron spectroscopy, x-ray absorption, and Auger electron spectroscopy. First spectroscopic results and experimental conditions are briefly discussed for Cu19 deposited onto the natural oxide layer of a Si-wafer surface.
Lineshape analysis of Raman scattering from LO and SO phonons in III-V nanowires
Authors: Begum N. , Bhatti A. S. , Jabeen F. , Rubini S. , Martelli F.
Published: December 2009

Micro-Raman spectroscopy is employed to study the phonon confinement in Au- and Mn-catalyzed GaAs and InAs nanowires. The phonon confinement model is used to fit the LO phonon peaks, which also takes into account the contribution to the asymmetry of the line shape due to the presence of surface optical (SO) phonons and structural defects. This also allows us to determine the correlation lengths in these wires, that is the average distance between defects and the defect density in these nanowires. Influence of these defects on the SO phonon is also investigated. A good agreement between the experimental results and the calculations for the SO phonon mode by using the dielectric continuum model is also obtained.
Thermoreversible associating polymer networks. I. Interplay of thermodynamics, chemical kinetics, and polymer physics
Authors: Hoy Robert S. , Fredrickson Glenn H.
Published: December 2009

Hybrid molecular dynamics/Monte Carlo simulations are used to study melts of unentangled, thermoreversibly associating supramolecular polymers. In this first of a series of papers, we describe and validate a model that is effective in separating the effects of thermodynamics and chemical kinetics on the dynamics and mechanics of these systems, and is extensible to arbitrarily nonequilibrium situations and nonlinear mechanical properties. We examine the model’s quiescent (and heterogeneous) dynamics, nonequilibrium chemical dynamics, and mechanical properties. Many of our results may be understood in terms of the crossover from diffusion-limited to kinetically limited sticky bond recombination, which both influences and is influenced by polymer physics, i.e., the connectivity of the parent chains.
A terahertz two-wire waveguide with low bending loss
Authors: Mbonye Marx , Mendis Rajind , Mittleman Daniel M.
Published: December 2009

We present experimental and theoretical evidence for low loss terahertz pulse propagation along a two-wire waveguide. We find that the mode pattern at the end of the waveguide resembles that of a dipole, consistent with the fundamental transverse-electromagnetic mode of the structure. Compared to the weakly guided Sommerfeld wave of a single wire, this structure exhibits much lower bending losses. We also observe that a commercial 300 Ω two-wire TV-antenna cable can be used for guiding frequency components up to ∼0.2 THz, although they are generally designed to operate only up to about 800 MHz.
The photodissociation of oxetane at 193 nm as the reverse of the Paterno–Buchi reaction
Authors: Lee Shih-Huang
Published: December 2009

We investigated the photodissociation of oxetane (1,3-trimethylene oxide) at 193.3 nm in a molecular-beam apparatus using photofragment-translational spectroscopy and selective photoionization. We measured time-of-flight (TOF) spectra and angular anisotropy parameters β(t) as a function of flight time of products at m/z=26–30 u utilizing photoionization energies from 9.8 to 14.8 eV. The TOF distributions of the products alter greatly with the employed photon energy, whereas their β(t) distributions are insensitive to the photon energy. Dissociation to H2CO+C2H4 is the major channel in the title reaction. Three distinct dissociation paths with branching ratios 0.923:0.058:0.019 are responsible for the three features observed in the distribution of kinetic energy released in the channel H2CO+C2H4. The observation of H2 and H atoms, ∼1% in branching, indicates that products H2CO and C2H4 spontaneously decompose to only a small extent. Most HCO, C2H3, and C2H2 ions originate from dissociative photoionization of products H2CO and C2H4. Except atomic H and H2, the photoproducts have large angular anisotropies, β≥−0.8, which reflects rapid dissociation of oxetane following optical excitation at 193.3 nm. The mechanisms of dissociation of oxetane are addressed. Our results confirm the quantum-chemical calculations of Palmer et al. and provide profound insight into the Paterno–Buchi reaction.
Flexible CO2 laser system for fundamental research related to an extreme ultraviolet lithography source
Authors: Tao Y. , Tillack M. S. , Amin N. , Burdt R. A. , Yuspeh S. , Shaikh N. M. , Najmabadi F.
Published: December 2009

A CO2 laser system with flexible parameters was developed for fundamental research related to an extreme ultraviolet (EUV) lithography source. The laser is a master oscillator and power amplifier (MOPA) system, consisting of a master oscillator, an externally triggered plasma switch, a preamplifier, a main amplifier, and electronic synchronization units. The laser pulse duration can be varied easily from 10 to 110 ns, with a constant peak power for pulse durations from 25 to 110 ns. The MOPA laser system can also be operated in dual-oscillator mode to produce laser pulse with pulse duration as long as 200ns and a train of laser pulses with flexible interval. The divergence of the laser beam is 1.3 times the diffraction limit. The laser intensity on the target surface can be up to 8×1010 W/cm2. Utilizing this CO2 MOPA laser system, high conversion efficiency from laser to in-band (2% bandwidth) 13.5 nm EUV emission has been demonstrated over a wide range of laser pulse durations.
Terahertz pulsed spectroscopic imaging using optimized binary masks
Authors: Shen Y. C. , Gan L. , Stringer M. , Burnett A. , Tych K. , Shen H. , Cunningham J. E. , Parrott E. P. J. , Zeitler J. A. , Gladden L. F. , Linfield E. H. , Davies A. G.
Published: December 2009

We report the development of a terahertz pulsed spectroscopic imaging system based on the concept of compressive sensing. A single-point terahertz detector, together with a set of 40 optimized two-dimensional binary masks, was used to measure the terahertz waveforms transmitted through a sample. Terahertz time- and frequency-domain images of the sample comprising 20×20 pixels were subsequently reconstructed. We demonstrate that both the spatial distribution and the spectral characteristics of a sample can be obtained by this means. Compared with conventional terahertz pulsed imaging, no raster scanning of the object is required, and ten times fewer terahertz spectra need be taken. It is therefore ideal for real-time imaging applications.
Explicit connection between sample geometry and Hall response
Authors: Paul Oliver , Cornils Martin
Published: December 2009

The linear galvanomagnetic response of four-contact devices to the presence of a magnetic field B is deduced from two normalized current densities ja0 and jb0 in the device under rotated biasing conditions in the absence of B. When B and the transport coefficients are homogeneous, the integrals of the scalar and cross products of ja0 and jb0 over the device volume fully capture the influence of the device geometry on the measured offset signal and Hall voltage, respectively. As a consequence, the galvanomagnetic response of homogeneous planar devices exhibiting fourfold rotational symmetry is parameterized by a single geometric parameter.
Nonequilibrium many body theory for quantum transport in terahertz quantum cascade lasers
Authors: Schmielau T. , Pereira M. F.
Published: December 2009

This paper presents a predictive Keldysh nonequilibrium many body Green’s functions theory for quantum transport including high order electron-electron, electron-phonon, electron-impurity, and interface roughness scattering processes. Our approach is fully frequency and momentum dependent including nondiagonal dephasing terms in both frequency and k-space. A detailed balance between coherent and scattering processes leads to local current conservation even if a small number of states is considered. Good agreement with experiments is obtained for a terahertz quantum cascade laser.
Control of current-jump induced by voltage, temperature, light in p-type GaAs: Programmable critical temperature sensor
Authors: Choi Sungyoul , Kim Bong-Jun , Lee Yong Wook , Lim Yong Sik , Choi Jeongyong , Kim Hyun-Tak
Published: December 2009

For two-terminal devices fabricated by Be (or Mn)-doped p-type epitaxial GaAs thin films, when the Mott metal-insulator transition (MIT) as current jump occurs, we observe that the energy gap of GaAs is not shifted, its peak intensity decreases in an applied voltage, and that the MIT temperature is between 410 and 440 K, and that the current jump is controlled by temperature, voltage and light intensity. The control of the jump voltage, a characteristic of the Mott MIT, reveals that these devices can be applied for programmable critical temperature sensors or optical sensors with high sensitivity.
Impact of dopant compensation on the deactivation of boron-oxygen recombination centers in crystalline silicon
Authors: Lim Bianca , Liu An , Macdonald Daniel , Bothe Karsten , Schmidt Jan
Published: December 2009

The boron-oxygen recombination center responsible for the light-induced degradation of Czochralski silicon solar cells can be permanently deactivated by illumination at elevated temperature. In this study, we examine the impact of dopant compensation on the deactivation process. The experimental results show that the deactivation rate depends inversely on the total boron concentration instead of the net doping concentration, suggesting that boron is directly involved in the deactivation process. A linear dependence of the activation energy on the total boron concentration further supports this conclusion.
An image-guided atomistic reconstruction of pyrolytic carbons
Authors: Leyssale Jean-Marc , Da Costa Jean-Pierre , Germain Christian , Weisbecker Patrick , Vignoles Gérard L.
Published: December 2009

A method for the generation of atomistic models of dense nanotextured carbons is presented. This method is based on the statistical analysis of high resolution transmission electron microscopy images and their three-dimensional (3D) extension through image synthesis under constraint. The resulting 3D images then serve as an external potential bringing the atoms to settle preferentially on the black areas during a conventional simulated annealing simulation. Application of this method to the case of two laminar pyrocarbons, differing in their degree of disorder, highlights the promising nature of this approach.
Strain-rate dependent shear viscosity of the Gaussian core model fluid
Authors: Ahmed Alauddin , Mausbach Peter , Sadus Richard J.
Published: December 2009

Nonequilibrium molecular dynamics simulations are reported for the shear viscosity of the Gaussian core model (GCM) fluid over a wide range of densities, temperatures and strain rates. A transition from Newtonian and non-Newtonian behavior is observed in all cases for sufficiently high strain rates. On the high-density side of the solid region where re-entrant melting occurs, the shear viscosity decreases significantly when the density is increased at constant temperature and Newtonian behavior persists until very high strain rates. This behavior, which is attributed to particle overlap, is in contrast to the monotonic increase in shear viscosity with density observed for the Lennard-Jones potential. Contrary to the behavior of normal fluids, the viscosity is observed to increase with increasing temperatures at high densities. This reflects a peculiarity of the GCM, namely the approach to the “infinite-density ideal-gas limit.” The behavior is also consistent with viscosity measurements of cationic surfactant solutions. In contrast to other potentials, the shear viscosities for the Gaussian core potential at low to moderate strain rates are obtained with modest statistical uncertainties. Zero shear viscosities extrapolated from the nonequilibrium simulations are in good agreement with equilibrium Green–Kubo calculations.
Rubber Hand Illusions and Size–Weight Illusions: Self-Representation Modulates Representation of External Objects
Authors: Haggard Patrick , Jundi Shyma
Published: December 2009

Bodily illusions offer an experimental method to investigate the origins and functional role of the sense of one's own body. Using the rubber hand illusion (RHI) we show that a representation of one's own body is implicitly used to calibrate perception of external objects. Twelve participants experienced the RHI while watching stimulation of a large or small glove simultaneously with stimulation of their own hand. They then grasped cylinders of identical size but varying weight. RHI with the large glove caused the cylinders to feel heavier. We suggest that an illusory increase in hand size made the subsequently grasped cylinder feel correspondingly small, evoking a size–weight illusion. Self-representation thus influenced exteroception. The sense of one's own body provides a fundamental reference for perception in general.
Two-Dimensional Layered Metal - Organic Frameworks of Lanthanum(III) Pyridine-2,6-dicarboxylate
Authors: Liu Yong-Ru , Yang Tao , Li Lei , Liu Jun-Min , Su Cheng-Yong
Published: December 2009

Three two-dimensional (2D) LaIII metal–organic frameworks, {[La4(pda)6(H2O)8]·2H2O}
n
(1), {[La2(pda)3(H2O)4]·H2O}
n
(2), and {[La2(pda)2(H2O)5SO4]·2H2O}
n
(3) (pda = pyridine-2,6-dicarboxylate), have been synthesized under hydro(solvo)thermal conditions and characterized by means of X-ray single-crystal diffraction, X-ray powder diffraction, and IR spectroscopy. Complexes 1 and 2 crystallize in the same triclinic system of a P-1 space group, share the same composition, and 4·82 net topology, but have a different local coordination environment and symmetry for the LaIII ions, thus they form a pair of supramolecular isomers. Complex 3 contains two kinds of crystallographically independent LaIII ions and bis-chelating SO4
2– anions, to generate a 2D grid structure of (4, 4) topology. All three complexes display layered crystal packing in the crystal lattice. The thermogravimetric analyses indicate that the solvated and coordinated water molecules in all complexes can be removed upon heating, and the frameworks decompose above 400°C.
New Copper(II) and Nickel(II) Complexes with Bifunctional Tetrazolate-5-carboxylate Ligands: Syntheses, Crystal Structures, and Magnetic Properties
Authors: Wu A-Qing , Chen Qi-Yong , Wu Mei-Feng , Zheng Fa-Kun , Chen Feng , Guo Guo-Cong , Huang Jin-Shun
Published: December 2009

Four new complexes with bifunctional tetrazolate-5-carboxylate ligands of 1H-tetrazole-5-formic acid (H2tzf) and 1H-tetrazole-5-acetic acid (H2tza), namely two dinuclear [M(tzf)(H2O)3]2·2H2O (M = Cu 1, Ni 2) and two mononuclear [Cu(tzf)(2,2′-bipy)2]·5H2O 3 and Cu(tza)(2,2′-bipy)H2O 4, were prepared and structurally characterized by single-crystal X-ray diffraction. Two different coordination modes of tetrazolate-5-carboxylate ligands exist: a tridentate N,O-chelated-N-bridged mode in 1 and 2, and a bidentate N,O-chelated mode in 3 and 4, which was first observed for the tetrazolate-5-carboxylate complexes. Extensive hydrogen bonds play an important role in the construction of the supramolecular network. Variable-temperature magnetic susceptibility data show the presence of antiferromagnetic interactions in 1 and 2. The thermogravimetric analyses of complexes 1–4 are also discussed.
Campbell's monkeys concatenate vocalizations into context-specific call sequences
Authors: Ouattara Karim , Lemasson Alban , Zuberbühler Klaus
Published: December 2009

Primate vocal behavior is often considered irrelevant in modeling human language evolution, mainly because of the caller's limited vocal control and apparent lack of intentional signaling. Here, we present the results of a long-term study on Campbell's monkeys, which has revealed an unrivaled degree of vocal complexity. Adult males produced six different loud call types, which they combined into various sequences in highly context-specific ways. We found stereotyped sequences that were strongly associated with cohesion and travel, falling trees, neighboring groups, nonpredatory animals, unspecific predatory threat, and specific predator classes. Within the responses to predators, we found that crowned eagles triggered four and leopards three different sequences, depending on how the caller learned about their presence. Callers followed a number of principles when concatenating sequences, such as nonrandom transition probabilities of call types, addition of specific calls into an existing sequence to form a different one, or recombination of two sequences to form a third one. We conclude that these primates have overcome some of the constraints of limited vocal control by combinatorial organization. As the different sequences were so tightly linked to specific external events, the Campbell's monkey call system may be the most complex example of ‘proto-syntax’ in animal communication known to date.
FM dyes enter via a store-operated calcium channel and modify calcium signaling of cultured astrocytes
Authors: Li Dongdong , Hérault Karine , Oheim Martin , Ropert Nicole
Published: December 2009

The amphiphilic fluorescent styryl pyridinium dyes FM1-43 and FM4-64 are used to probe activity-dependent synaptic vesicle cycling in neurons. Cultured astrocytes can internalize FM1-43 and FM4-64 inside vesicles but their uptake is insensitive to the elevation of cytosolic calcium (Ca
2+
) concentration and the underlying mechanism remains unclear. Here we used total internal reflection fluorescence microscopy and pharmacological tools to study the mechanisms of FM4-64 uptake into cultured astrocytes from mouse neocortex. Our data show that: (
i
) endocytosis is not a major route for FM4-64 uptake into astrocytes; (
ii
) FM4-64 enters astrocytes through an aqueous pore and strongly affects Ca
2+
homeostasis; (
iii
) partitioning of FM4-64 into the outer leaflet of the plasma membrane results in a facilitation of store-operated Ca
2+
entry (SOCE) channel gating; (
iv
) FM4-64 permeates and competes with Ca
2+
for entry through a SOCE channel; (
v
) intracellular FM4-64 mobilizes Ca
2+
from the endoplasmic reticulum stores, conveying a positive feedback to activate SOCE and to sustain dye uptake into astrocytes. Our study demonstrates that FM dyes are not markers of cycling vesicles in astrocytes and calls for a careful interpretation of FM fluorescence.
A genome-wide screen in
Saccharomyces cerevisiae
reveals a critical role for the mitochondria in the toxicity of a trichothecene mycotoxin
Authors: McLaughlin John E. , Bin-Umer Mohamed Anwar , Tortora Andrew , Mendez Natasha , McCormick Susan , Tumer Nilgun E.
Published: December 2009

Trichothecene mycotoxins synthesized by
Fusarium
species are potent inhibitors of eukaryotic translation. They are encountered in both the environment and in food, posing a threat to human and animal health. They have diverse roles in the cell that are not limited to the inhibition of protein synthesis. To understand the trichothecene mechanism of action, we screened the yeast knockout library to identify genes whose deletion confers resistance to trichothecin (Tcin). The largest group of resistant strains affected mitochondrial function, suggesting a role for fully active mitochondria in trichothecene toxicity. Tcin inhibited mitochondrial translation in the wild-type strain to a greater extent than in the most resistant strains, implicating mitochondrial translation as a previously unrecognized site of action. The Tcin-resistant strains were cross-resistant to anisomycin and chloramphenicol, suggesting that Tcin targets the peptidyltransferase center of mitochondrial ribosomes. Tcin-induced cell death was partially rescued by mutants that regulate mitochondrial fusion and maintenance of the tubular morphology of mitochondria. Treatment of yeast cells with Tcin led to the fragmentation of the tubular mitochondrial network, supporting a role for Tcin in disruption of mitochondrial membrane morphology. These results provide genome-wide insight into the mode of action of trichothecene mycotoxins and uncover a critical role for mitochondrial translation and membrane maintenance in their toxicity.
Worthy the Name of a Grammar
Authors: Fountain Catherine
Published: December 2009

This article compares two missionary grammars written in the middle of the 17th century, Horacio Carochi’s (1579–1662)Arte de la Lengua Mexicana con la declaración de los adverbios della(1645) and John Eliot’s (1604–1690)The Indian Grammar Begun: or, an Essay to Bring the Indian Language into Rules(1666). Although published only 21 years apart, the two works differ in both context and theoretical underpinnings. These differences are manifested both in the type and depth of analysis undertaken by each author. Indeed, Carochi’s analysis goes much deeper and offers a more complete description of the language treated. While this can be attributed in part to Carochi’s own linguistic ability, the quality and completeness of his grammar is due in large part to the existence of a tradition of scholarship concerning Nahuatl in New Spain, a tradition that is strikingly absent in New England of the time.
Léxico purépecha en tiempos de la Ilustración
Authors: Villavicencio Frida
Published: December 2009

En 1756 Joseph Zepherino Botello Movellan (1734–c.1785) terminó de componer unCathecismo breve en lengua tarasca. Dicha obra fue escrita en purépecha o tarasco, una lengua indígena que aún hoy es hablada por cerca de 100,000 personas que radican en la parte noroccidental del estado de Michoacán, México. Éste es, hasta donde sabemos, el único documento de corte religioso escrito en esta lengua durante el siglo XVIII En esta obra el autor incluyó cuatro listas de palabras que en conjunto constituyen un breve vocabulario de la lengua de Michoacán. Sin tener la extensión ni la importancia de los trabajos lexicográficos que fueron realizados durante el siglo XVI, el valor de este documento consiste en ser el único testimonio de este tipo con el que contamos para conocer uno de los períodos menos documentados en la historia de la lengua.

En este artículo se describen las características generales del catecismo de Botello incluyendo las cuatro secciones lexicográficas prestando especial atención a la lista de partes del cuerpo. Como punto de referencia para el análisis se utiliza la lista de partes del cuerpo que aparece en el Diccionario de Lagunas (editado en 1574), así como información proveniente de diversos diccionarios actuales. El material lingüístico que encontramos en la obra de Botello nos permite hacernos una buena idea del el purépecha del siglo XVIII y nos ayuda a entender más sobre el desarrollo que ha experimentado esta lengua en casi cinco siglos de historia. También nos provee interesantes datos sobre diversos tópicos, entre ellos: la representación ortográfica, la variación dialectal, los procesos de gramaticalización y derivación, la introducción de préstamos y algunas relaciones semánticas. Por último, en el texto de Botello también encontramos algunos datos interesantes para el español utilizado en México durante esa época.
Australian Young People's Awareness of Headspace, Beyondblue and other Mental Health Organizations
Authors: Jorm Anthony F.
Published: December 2009

Objective: The aim of this paper is to assess young people's awareness of mental health organizations supporting their age group. Of particular interest was awareness of headspace, which was created in 2006 to provide youth-oriented mental health services, and of beyondblue, which aims to raise community awareness of depression, anxiety and related disorders.

Method: A telephone survey was carried out on a national sample of young people who were part of a 2-year follow-up study of youth mental health literacy. Data were analysed for those aged 13–25 years.

Results: Awareness was highest for beyondblue and telephone helplines; headspace had established some awareness, particularly in areas where its services operate. However, awareness was unrelated to the participant's psychological symptoms in the past year.

Conclusions: If youth-oriented services are to be successful, young people need to know about them. Awareness campaigns need to be targeted at the sub-group who have greatest need for these services, namely those with mental health problems.
Challenges in Psychiatric Classification: The Case of Generalized Anxiety Disorder
Authors: Ash David , Galletly Cherrie
Published: December 2009

Objective: This paper aims to describe some of the challenges in psychiatric classification, using generalized anxiety disorder (GAD) as an example. A range of different conceptualizations of GAD are presented. Some are based on theoretical formulations, while others draw on epidemiological data. Each has merit, but also deficiencies. The evolution of diagnostic criteria is not simply a theoretical exercise, but reflects assumptions about the nature of the underlying pathology and the relationships between different disorders. Furthermore, these criteria determine which subjects are included in research and in clinical trials, so they shape the further development of psychiatric classification systems.

Conclusion: The controversies about the classification of GAD illustrate the complexities and challenges of developing a valid classification system for psychiatric disorders.
Pearl in the Oyster: Climate Change as a Mental Health Opportunity
Authors: Berry Helen
Published: December 2009

Objective: Our world faces potentially catastrophic climate change and we have limited capacity to adapt to rapid or extreme climatic changes. As a result, we can expect significant adverse impacts on health. This includes mental health, a major and growing global concern. It is essential to understand how to respond quickly, effectively and within a manageable budget. The aim of this paper is to propose that the adverse consequences of climate change might offer a subtle but important mental health promotion opportunity which meets these criteria.

Conclusions: Climate change will affect mental health directly through increasing exposure to trauma, and indirectly through harming physical health and damaging the physical environment on which economic opportunity depends. Disadvantaged people and communities, especially in rural and remote Australia, will be hardest hit. Seminal work by Alexander Leighton demonstrated how profound disadvantage and associated elevated psychiatric morbidity could be addressed by building community capacity. His methods might be adapted, using the need to address adverse climate change as an opportunity to build social capital. Social capital is associated with a wide range of socioeconomic and health advantages, particularly decreased psychiatric morbidity.
‘Radical Hope’ and Rain: Climate Change and the Mental Health of Indigenous Residents of Northern Australia
Authors: Hunter Ernest
Published: December 2009

Objective: This paper considers the short, intermediate and longer term effects of climate change in relation to the mental health of Indigenous residents of northern Australia, and what these effects mean in terms of supporting adaptation and resilience.

Conclusions: Indigenous Australians have contended with change for millennia, with the drivers shifting from ecological to social pressures since European colonization. Climate change resulting from human activities introduces a new set of change forces which will in the short term be mediated by economic and social effects internationally.
Expanding Psychiatry Training: Australian Specialists’ and Trainees’ Perceived Gaps in Experiences and Settings
Authors: O'Connor Daniel , Schweizer Yolanda , Spratt Christine
Published: December 2009

Objective: The Royal Australian and New Zealand College of Psychiatrists (RANZCP) is working together with the Australian Federal Government to expand the range of training experiences and settings with the object of producing better equipped and better distributed psychiatrists to address the rising prevalence of mental disorder. To assist in this process, the College sought the views of its Fellows (psychiatrists) and trainees concerning important gaps in clinical experience and the settings best suited to filling them.

Method: An electronic survey was sent to all Australian RANZCP psychiatrists and trainees in June 2008.

Results: Only 15% of psychiatrists and 28% of trainees responded to the survey. There was striking concordance, however, that psychological therapies required much greater emphasis and that this experience would best be acquired in the private healthcare system.

Conclusions: These findings support the recommendations of the Medical Specialist Training Steering Committee's report on expanded settings, suggesting that RANZCP members are likely to engage enthusiastically in the expanded specialist training program. It will be important to ensure that trainees are well supervised in their treatment of anxiety, affective and substance abuse disorders.
Patient Aggression Perceived by Community Support Workers
Authors: Gale Christopher , Hannah Annette , Swain Nicola , Gray Andrew , Coverdale John , Oud Nico
Published: December 2009

Objective: Aggression by patients is a known risk factor for hospital workers. Within New Zealand, the bulk of ongoing care for physical and mental disabilities and health issues is not hospital based, but contracted to various non-governmental agencies. The rate of client aggression towards care workers from these organizations, to our knowledge, has not been assessed.

Method: Two hundred and forty-two support workers in non-governmental agencies caring for people with disabilities responded to an anonymous mailed survey on client aggression, personal distress, and communication style.

Results: Most support workers did experience verbal forms of aggression or destructive behaviour, fewer experienced physical aggression, and a minority were injured, sexually harassed, stalked or harassed by means of formal complaint. The median total violence score was five (interquartile range 12.25). A higher total violence score (using the POPAS-NZ) was associated with age and gender, the primary disability of clients, and the numbers of hours worked. The length of time worked was not associated with total violence risk. Communication style, after correcting for other factors, was a predictor of aggression. Almost 6% of care workers reported distress symptoms at a level associated with clinically significant stress reactions.

Conclusions: Patient aggression is common among care workers, and can cause distress in the minority. We suggest that further research to clarify risk factors and develop interventions for care workers is needed.
The solution of a coupled system of nonlinear physical problems using the homotopy analysis method
Authors: El-Wakil S A , Abdou M A
Published: December 2009

In this article, the homotopy analysis method (HAM) has been applied to solve coupled nonlinear evolution equations in physics. The validity of this method has been successfully demonstrated by applying it to two nonlinear evolution equations, namely coupled nonlinear diffusion reaction equations and the (2+1)-dimensional Nizhnik–Novikov Veselov system. The results obtained by this method show good agreement with the ones obtained by other methods.

The proposed method is a powerful and easy to use analytic tool for nonlinear problems and does not need small parameters in the equations. The HAM solutions contain an auxiliary parameter that provides a convenient way of controlling the convergence region of series solutions. The results obtained here reveal that the proposed method is very effective and simple for solving nonlinear evolution equations. The basic ideas of this approach can be widely employed to solve other strongly nonlinear problems.
New applications of He's homotopy perturbation method for nonlinear differential difference equations
Authors: Abdou M A
Published: December 2009

We extend He's homotopy perturbation method (HPM) with a computerized symbolic computation to find approximate and exact solutions for nonlinear differential difference equations (DDEs) arising in physics. The results reveal that the method is very effective and simple. We find that the extended method for nonlinear DDEs is of good accuracy. To illustrate the effectiveness and the advantage of the proposed method, three models of nonlinear DDEs of special interest in physics are chosen, namely, the hybrid equation, the Toda lattice equation and the relativistic Toda lattice difference equation. Comparisons are made between the results of the proposed method and exact solutions. The results show that the HPM is an attractive method for solving the DDEs.
Electric field generation by the electron beam filamentation instability: filament size effects
Authors: Dieckmann M E , Bret A
Published: December 2009

The filamentation instability (FI) of counter-propagating beams of electrons is modelled with a particle-in-cell simulation in one spatial dimension and with a high statistical plasma representation. The simulation direction is orthogonal to the beam velocity vector. Both electron beams have initially equal densities, temperatures and moduli of their non-relativistic mean velocities. The FI is electromagnetic in this case. A previous study of a small filament demonstrated that the magnetic pressure gradient force (MPGF) results in a nonlinearly driven electrostatic field. The probably small contribution of the thermal pressure gradient to the force balance implied that the electrostatic field performed undamped oscillations around a background electric field. Here, we consider larger filaments, which reach a stronger electrostatic potential when they saturate. The electron heating is enhanced and electrostatic electron phase space holes form. The competition of several smaller filaments, which grow simultaneously with the large filament, also perturbs the balance between the electrostatic and magnetic fields. The oscillations are damped but the final electric field amplitude is still determined by the MPGF.
Dynamically weighted clustering with noise set
Authors: Shen Yijing , Sun Wei , Li Ker-Chau
Published: December 2009

Motivation: Various clustering methods have been applied to microarray gene expression data for identifying genes with similar expression profiles. As the biological annotation data accumulated, more and more genes have been organized into functional categories. Functionally related genes may be regulated by common cellular signals, thus likely to be co-expressed. Consequently, utilizing the rapidly increasing functional annotation resources such as Gene Ontology (GO) to improve the performance of clustering methods is of great interest. On the opposite side of clustering, there are genes that have distinct expression profiles and do not co-express with other genes. Identification of these scattered genes could enhance the performance of clustering methods.

Results: We developed a new clustering algorithm, Dynamically Weighted Clustering with Noise set (DWCN), which makes use of gene annotation information and allows for a set of scattered genes, the noise set, to be left out of the main clusters. We tested the DWCN method and contrasted its results with those obtained using several common clustering techniques on a simulated dataset as well as on two public datasets: the Stanford yeast cell-cycle gene expression data, and a gene expression dataset for a group of genetically different yeast segregants.

Conclusion: Our method produces clusters with more consistent functional annotations and more coherent expression patterns than existing clustering techniques.

Contact:  yshen@stat.ucla.edu

Supplementary information:  Supplementary data are available at Bioinformatics online.
Ellagic Acid, the Active Compound of Phyllanthus urinaria, Exerts In Vivo Anti‐Angiogenic Effect and Inhibits MMP‐2 Activity
Authors: Huang Sheng-Teng , Wang Chen-Yu , Yang Rong-Chi , Wu Hsiao-Ting , Yang Su-Hui , Cheng Yung-Chi , Pang Jong-Hwei S.
Published: December 2009

This study aimed to assess the potential anti‐angiogenic mechanism of Phyllanthus urinaria (P. urinaria) and characterize the major compound in P. urinaria that exerts anti‐angiogenic effect. The water extract of P. urinaria and Ellagic Acid were used to evaluate the anti‐angiogenic effect in chorioallantoic membrane (CAM) in chicken embryo and human vascular endothelial cells (HUVECs). The matrix metalloproteinase‐2 (MMP‐2) activity was determined by gelatin zymography. The mRNA expressions of MMP‐2, MMP‐14 and tissue inhibitor of metalloproteinase‐2 (TIMP‐2) were analyzed by reverse transcription polymerase chain reaction (RT‐PCR). Level of MMP‐2 proteins in conditioned medium or cytosol was determined by western blot analysis. We confirmed that P. urinaria′s in vivo anti‐angiogenic effect was associated with a reduction in MMP‐2 activity. Ellagic acid, one of the major polyphenolic components as identified in P. urinaria by high performance liquid chromatography mass spectrometry (HPLC/MS), exhibited the same anti‐angiogenic effect in vivo. Both P. urinaria and Ellagic Acid inhibited MMP‐2 activity in HUVECs with unchanged mRNA level. The mRNA expression levels of MMP‐14 and TIMP‐2 were not altered either. Results from comparing the change of MMP‐2 protein levels in conditioned medium and cytosol of HUVECs after the P. urinaria or Ellagic Acid treatment revealed an inhibitory effect on the secretion of MMP‐2 protein. This study concluded that Ellagic Acid is the active compound in P. urinaria to exhibit anti‐angiogenic activity and to inhibit the secretion of MMP‐2 protein from HUVECs.
Does encephalization correlate with life history or metabolic rate in Carnivora?
Authors: Finarelli John A.
Published: December 2009

A recent analysis of brain size evolution reconstructed the plesiomorphic brain–body size allometry for the mammalian order Carnivora, providing an important reference frame for comparative analyses of encephalization (brain volume scaled to body mass). I performed phylogenetically corrected regressions to remove the effects of body mass, calculating correlations between residual values of encephalization with basal metabolic rate (BMR) and six life-history variables (gestation time, neonatal mass, weaning time, weaning mass, litter size, litters per year). No significant correlations were recovered between encephalization and any life-history variable or BMR, arguing against hypotheses relating encephalization to maternal energetic investment. However, after correcting for clade-specific adaptations, I recovered significant correlations for several variables, and further analysis revealed a conserved carnivoran reproductive strategy, linking degree of encephalization to the well-documented mammalian life-history trade-off between neonatal mass and litter size. This strategy of fewer, larger offspring correlating with increased encephalization remains intact even after independent changes in encephalization allometries in the evolutionary history of this clade.
Impending conservation crisis for Southeast Asian amphibians
Authors: Rowley Jodi , Brown Rafe , Bain Raoul , Kusrini Mirza , Inger Robert , Stuart Bryan , Wogan Guin , Thy Neang , Chan-ard Tanya , Trung Cao Tien , Diesmos Arvin , Iskandar Djoko T. , Lau Michael , Ming Leong Tzi , Makchai Sunchai , Truong Nguyen Quang , Phimmachak Somphouthone
Published: December 2009

With an understudied amphibian fauna, the highest deforestation rate on the planet and high harvesting pressures, Southeast Asian amphibians are facing a conservation crisis. Owing to the overriding threat of habitat loss, the most critical conservation action required is the identification and strict protection of habitat assessed as having high amphibian species diversity and/or representing distinctive regional amphibian faunas. Long-term population monitoring, enhanced survey efforts, collection of basic biological and ecological information, continued taxonomic research and evaluation of the impact of commercial trade for food, medicine and pets are also needed. Strong involvement of regional stakeholders, students and professionals is essential to accomplish these actions.
Poverty trap formed by the ecology of infectious diseases
Authors: Bonds Matthew H. , Keenan Donald C. , Rohani Pejman , Sachs Jeffrey D.
Published: December 2009

While most of the world has enjoyed exponential economic growth, more than one-sixth of the world is today roughly as poor as their ancestors were many generations ago. Widely accepted general explanations for the persistence of such poverty have been elusive and are needed by the international development community. Building on a well-established model of human infectious diseases, we show how formally integrating simple economic and disease ecology models can naturally give rise to poverty traps, where initial economic and epidemiological conditions determine the long-term trajectory of the health and economic development of a society. This poverty trap may therefore be broken by improving health conditions of the population. More generally, we demonstrate that simple human ecological models can help explain broad patterns of modern economic organization.
The role of extinction in large-scale diversity–stability relationships
Authors: Simpson Carl , Kiessling Wolfgang
Published: December 2009

More-diverse communities are thought to be ecologically stable because a greater number of ecological interactions among members allows for the increases in robustness and resilience. Diversity–stability relationships have mostly been studied on short ecological time scales but one study has identified such patterns over million-year time scales in reef communities. Here we propose and test a hypothesis for the mechanism of large-scale diversity–stability relationships in reefs. The extinction of community members destabilizes the community as a whole, unless there is sufficient diversity to buffer the community from the stochastic loss of members, thereby preventing collapse. If genera have high extinction rates, any variation in diversity among communities will result in a diversity–stability relationship. Conversely, in the absence of other mechanisms, the stability of low extinction communities is expected to be independent of diversity. We compare the extinction rates of six reef-building metazoan taxa to patterns of reef community stability and reef volume. We find that extinction of reef-builders occurs independent of reef volume, and that the strength of the diversity–stability relationship varies positively with extinction rate.
SEUSSandSEUSS-LIKETranscriptional Adaptors Regulate Floral and Embryonic Development in Arabidopsis
Authors: Bao Fang , Azhakanandam Sridevi , Franks Robert G.
Published: December 2009

Multimeric protein complexes are required during development to regulate transcription and orchestrate cellular proliferation and differentiation. The Arabidopsis (Arabidopsis thaliana) SEUSS (SEU) gene encodes a transcriptional adaptor that shares sequence similarity with metazoan Lim domain-binding transcriptional adaptors. In Arabidopsis, SEU forms a physical complex with the LEUNIG transcriptional coregulator. This complex regulates a number of diverse developmental events, including proper specification of floral organ identity and number and the development of female reproductive tissues derived from the carpel margin meristem. In addition to SEU, there are three Arabidopsis SEUSS-LIKE (SLK) genes that encode putative transcriptional adaptors. To determine the functions of the SLK genes and to investigate the degree of functional redundancy between SEU and SLK genes, we characterized available slk mutant lines in Arabidopsis. Here, we show that mutations in any single SLK gene failed to condition an obvious morphological abnormality. However, by generating higher order mutant plants, we uncovered a degree of redundancy between the SLK genes and between SLK genes and SEU. We report a novel role for SEU and the SLK genes during embryonic development and show that the concomitant loss of both SEU and SLK2 activities conditions severe embryonic and seedling defects characterized by a loss of the shoot apical meristem. Furthermore, we demonstrate that SLK gene function is required for proper development of vital female reproductive tissues derived from the carpel margin. We propose a model that posits that SEU and SLK genes support organ development from meristematic regions through two different pathways: one that facilitates auxin response and thus organ initiation and a second that sustains meristematic potential through the maintenance of SHOOTMERISTEM-LESS and PHABULOSA expression.