bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydration and hydrogen bond network of water around hydrophobic surface investigated by terahertz spectroscopy
Authors: Shiraga K. , Suzuki T. , Kondo N. , Ogawa Y.
Published: December 2014

Water conformation around hydrophobic side chains of four amino acids (glycine, L-alanine, L-aminobutyric acid, and L-norvaline) was investigated via changes in complex dielectric constant in the terahertz (THz) region. Each of these amino acids has the same hydrophilic backbone, with successive additions of hydrophobic straight methylene groups (–CH2–) to the side chain. Changes in the degree of hydration (number of dynamically retarded water molecules relative to bulk water) and the structural conformation of the water hydrogen bond (HB) network related to the number of methylene groups were quantitatively measured. Since dielectric responses in the THz region represent water relaxations and water HB vibrations at a sub-picosecond and picosecond timescale, these measurements characterized the water relaxations and HB vibrations perturbed by the methylene apolar groups. We found each successive straight –CH2– group on the side chain restrained approximately two hydrophobic hydration water molecules. Additionally, the number of non-hydrogen-bonded (NHB) water molecules increased slightly around these hydrophobic side chains. The latter result seems to contradict the iceberg model proposed by Frank and Evans, where water molecules are said to be more ordered around apolar surfaces. Furthermore, we compared the water–hydrophilic interactions of the hydrophilic amino acid backbone with those with the water–hydrophobic interactions around the side chains. As the hydrophobicity of the side chain increased, the ordering of the surrounding water HB network was altered from that surrounding the hydrophilic amino acid backbone, thereby diminishing the fraction of NHB water and ordering the surrounding tetrahedral water HB network.
Dynamics in the quantum/classical limit based on selective use of the quantum potential
Authors: Garashchuk Sophya , Dell’Angelo David , Rassolov Vitaly A.
Published: December 2014

A classical limit of quantum dynamics can be defined by compensation of the quantum potential in the time-dependent Schrödinger equation. The quantum potential is a non-local quantity, defined in the trajectory-based form of the Schrödinger equation, due to Madelung, de Broglie, and Bohm, which formally generates the quantum-mechanical features in dynamics. Selective inclusion of the quantum potential for the degrees of freedom deemed “quantum,” defines a hybrid quantum/classical dynamics, appropriate for molecular systems comprised of light and heavy nuclei. The wavefunction is associated with all of the nuclei, and the Ehrenfest, or mean-field, averaging of the force acting on the classical degrees of freedom, typical of the mixed quantum/classical methods, is avoided. The hybrid approach is used to examine evolution of light/heavy systems in the harmonic and double-well potentials, using conventional grid-based and approximate quantum-trajectory time propagation. The approximate quantum force is defined on spatial domains, which removes unphysical coupling of the wavefunction fragments corresponding to distinct classical channels or configurations. The quantum potential, associated with the quantum particle, generates forces acting on both quantum and classical particles to describe the backreaction.
Probing ground and low-lying excited states for HIO2 isomers
Authors: de Souza Gabriel L. C. , Brown Alex
Published: December 2014

We present a computational study on HIO2 molecules. Ground state properties such as equilibrium structures, relative energetics, vibrational frequencies, and infrared intensities were obtained for all the isomers at the coupled-cluster with single and double excitations as well as perturbative inclusion of triples (CCSD(T)) level of theory with the aug-cc-pVTZ-PP basis set and ECP-28-PP effective core potential for iodine and the aug-cc-pVTZ basis set for hydrogen and oxygen atoms. The HOIO structure is confirmed as the lowest energy isomer. The relative energies are shown to be HOIO < HOOI < HI(O)O. The HO(O)I isomer is only stable at the density functional theory (DFT) level of theory. The transition states determined show interconversion of the isomers is possible. In order to facilitate future experimental identification, vibrational frequencies are also determined for all corresponding deuterated species. Vertical excitation energies for the three lowest-lying singlet and triplet excited states were determined using the configuration interaction singles, time-dependent density functional theory (TD-DFT)/B3LYP, TD-DFT/G96PW91, and equation of motion-CCSD approaches with the LANL2DZ basis set plus effective core potential for iodine and the aug-cc-pVTZ basis set for hydrogen and oxygen atoms. It is shown that HOIO and HOOI isomers have excited states accessible at solar wavelengths (<4.0 eV) but these states have very small oscillator strengths (<2 × 10−3).
Geometry-dependent lifetime of Interatomic coulombic decay using equation-of-motion coupled cluster method
Authors: Ghosh Aryya , Vaval Nayana
Published: December 2014

Electronically excited atom or molecule in an environment can relax via transferring its excess energy to the neighboring atoms or molecules. The process is called Interatomic or Intermolecular coulombic decay (ICD). The ICD is a fast decay process in environment. Generally, the ICD mechanism predominates in weakly bound clusters. In this paper, we have applied the complex absorbing potential approach/equation-of-motion coupled cluster (CAP/EOMCCSD) method which is a combination of CAP and EOMCC approach to study the lifetime of ICD at various geometries of the molecules. We have applied this method to calculate the lifetime of ICD in Ne-X; X = Ne, Mg, Ar, systems. We compare our results with other theoretical and experimental results available in literature.
Probing chirality fluctuations in molecules by nonlinear optical spectroscopy
Authors: Mann N. , Nalbach P. , Mukamel S. , Thorwart M.
Published: December 2014

Symmetry breaking caused by geometric fluctuations can enable processes that are otherwise forbidden. An example is a perylene bisimide dyad whose dipole moments are perpendicular to each other. Förster-type energy transfer is thus forbidden at the equilibrium geometry since the dipolar coupling vanishes. Yet, fluctuations of the geometric arrangement have been shown to induce finite energy transfer that depends on the dipole variance, rather than the mean. We demonstrate an analogous effect associated with chirality symmetry breaking. In its equilibrium geometry, this dimer is non-chiral. The linear chiral response which depends on the average geometry thus vanishes. However, we show that certain 2D chiral optical signals are finite due to geometric fluctuations. Furthermore, the correlation time of these fluctuations can be experimentally revealed by the waiting time dependence of the 2D signal.
Investigation of cycle-to-cycle variations in an engine-like geometry
Authors: Schmitt M. , Frouzakis C. E. , Wright Y. M. , Tomboulides A. G. , Boulouchos K.
Published: December 2014

The multiple-cycle direct numerical simulation data of the flow in the valve/piston assembly investigated in Schmitt et al. [“Direct numerical simulation of multiple cycles in a valve/piston assembly,” Phys. Fluids 26, 035105 (2014)] is revisited to identify the relevant flow features leading to the observed cyclic variations. These are found to be the radial velocity at top dead center (TDC) remaining from the previous cycle, the location of the center of the hollow jet during intake and the strength and orientation of the vortex ring at bottom dead center. Comparisons between these features showed strong correlations in the flow field within a cycle and between two consecutive cycles. The trajectory of the hollow jet during intake is strongly influenced by the remaining radial velocity from the previous cycle. Subsequently, the hollow jet forms a vortex ring whose orientation and strength influences the radial velocity at TDC of the next cycle. This has in turn an effect on the jet trajectory of the following cycle. The results in this simplified geometry are a first attempt to understand the origin of cause-and-effect relationships of cycle-to-cycle variations (CCVs) in the flow field and can serve as a base for investigating CCVs in more realistic engine geometries. Moreover, the reported correlations are a useful validation platform for large Eddy simulation models.
Terahertz pulse generation from bulk GaAs by a tilted-pulse-front excitation at 1.8 μm
Authors: Blanchard F. , Schmidt B. E. , Ropagnol X. , Thiré N. , Ozaki T. , Morandotti R. , Cooke D. G. , Légaré F.
Published: December 2014

We report on terahertz (THz) generation via optical rectification in a room temperature gallium arsenide (GaAs) crystal pumped at a wavelength of 1.8 μm using a modified tilted-pulse-front scheme, leading to a 0.05% energy conversion efficiency. The spectral content of the measured THz pulses, ranging from 0.1 to 3 THz, confirmed a good broadband phase matching between the pump and the THz pulses over several millimeters (>20 mm) in a semi-insulating 〈110〉 cut bulk GaAs crystal. Our findings also suggest that the pump-to-THz conversion efficiency can be further increased by using a pump source with a narrower bandwidth.
Interpreting the behavior of a quarter-wave transmission line resonator in a magnetized plasma
Authors: Gogna G. S. , Karkari S. K. , Turner M. M.
Published: December 2014

The quarter wave resonator immersed in a strongly magnetized plasma displays two possible resonances occurring either below or above its resonance frequency in vacuum, fo. This fact was demonstrated in our recent articles [G. S. Gogna and S. K. Karkari, Appl. Phys. Lett. 96, 151503 (2010); S. K. Karkari, G. S. Gogna, D. Boilson, M. M. Turner, and A. Simonin, Contrib. Plasma Phys. 50(9), 903 (2010)], where the experiments were carried out over a limited range of magnetic fields at a constant electron density, ne. In this paper, we present the observation of dual resonances occurring over the frequency scan and find that ne calculated by considering the lower resonance frequency is 25%–30% smaller than that calculated using the upper resonance frequency with respect to fo. At a given magnetic field strength, the resonances tend to shift away from fo as the background density is increased. The lower resonance tends to saturate when its value approaches electron cyclotron frequency, fce. Interpretation of these resonance conditions are revisited by examining the behavior of the resonance frequency response as a function of ne. A qualitative discussion is presented which highlights the practical application of the hairpin resonator for interpreting ne in a strongly magnetized plasma.
Formation kinetics of copper-related light-induced degradation in crystalline silicon
Authors: Lindroos J. , Savin H.
Published: December 2014

Light-induced degradation (LID) is a deleterious effect in crystalline silicon, which is considered to originate from recombination-active boron-oxygen complexes and/or copper-related defects. Although LID in both cases appears as a fast initial decay followed by a second slower degradation, we show that the time constant of copper-related degradation increases with increasing boron concentration in contrast to boron-oxygen LID. Temperature-dependent analysis reveals that the defect formation is limited by copper diffusion. Finally, interface defect density measurements confirm that copper-related LID is dominated by recombination in the wafer bulk.
Magnetic antenna excitation of whistler modes. I. Basic properties
Authors: Urrutia J. M. , Stenzel R. L.
Published: December 2014

Properties of magnetic loop antennas for exciting electron whistler modes have been investigated in a large laboratory plasma. The parameter regime is that of large plasma frequency compared to the cyclotron frequency and signal frequency below half the cyclotron frequency. The antenna diameter is smaller than the wavelength. Different directions of the loop antenna relative to the background magnetic field have been measured for small amplitude waves. The differences in the topology of the wave magnetic field are shown from measurements of the three field components in three spatial directions. The helicity of the wave magnetic field and of the hodogram of the magnetic vector in space and time are clarified. The superposition of wave fields is used to investigate the properties of two antennas for small amplitude waves. Standing whistler waves are produced by propagating two wave packets in opposite directions. Directional radiation is obtained with two phased loops separated by a quarter wavelength. Rotating antenna fields, produced with phased orthogonal loops at the same location, do not produce directionality. The concept of superposition is extended in a Paper II to generate antenna arrays for whistlers. These produce nearly plane waves, whose propagation angle can be varied by the phase shifting the currents in the array elements. Focusing of whistlers is possible. These results are important for designing antennas on spacecraft or diagnosing and heating of laboratory plasmas.
Measurement of ion density in an atmospheric pressure argon with pin-to-plate dielectric barrier discharge by resonance of plasma radiation
Authors: Qi Bing , Pan Lizhu , Zhou Qiujiao , Huang Jianjun , Liu Ying
Published: December 2014

The measurements of the ion densities in the atmospheric AC barrier corona argon discharge are carried out by receiving and analyzing the frequencies of the electromagnetic radiation emitted from the plasma. An auxiliary excitation source composed of a pin-to-pin discharge system is introduced to excite the oscillations of the main discharge. To analyze the resonance mechanism, a complemented model based on a one-dimensional description of forced vibrations is given. Calculations indicate that Ar2+ is the dominant ion (∼89% in number density). By analyzing resonance frequencies, the ion densities of Ar2+ are in the order of 1019∼1020m−3 and increase slowly as the applied voltage increases.
Frequency division using a micromechanical resonance cascade
Authors: Qalandar K. R. , Strachan B. S. , Gibson B. , Sharma M. , Ma A. , Shaw S. W. , Turner K. L.
Published: December 2014

A coupled micromechanical resonator array demonstrates a mechanical realization of multi-stage frequency division. The mechanical structure consists of a set of N sequentially perpendicular microbeams that are connected by relatively weak elastic elements such that the system vibration modes are localized to individual microbeams and have natural frequencies with ratios close to 1:2:⋯:2N. Conservative (passive) nonlinear inter-modal coupling provides the required energy transfer between modes and is achieved by finite deformation kinematics. When the highest frequency beam is excited, this arrangement promotes a cascade of subharmonic resonances that achieve frequency division of 2j at microbeam j for j = 1, …, N. Results are shown for a capacitively driven three-stage divider in which an input signal of 824 kHz is passively divided through three modal stages, producing signals at 412 kHz, 206 kHz, and 103 kHz. The system modes are characterized and used to delineate the range of AC input voltages and frequencies over which the cascade occurs. This narrow band frequency divider has simple design rules that are scalable to higher frequencies and can be extended to a larger number of modal stages.
Microwave shielding enhancement of high-transparency, double-layer, submillimeter-period metallic mesh
Authors: Lu Zhengang , Wang Heyan , Tan Jiubin , Lin Shen
Published: December 2014

We demonstrate both theoretically and experimentally that the microwave-shielding effectiveness of a double-layer metallic mesh with a submillimeter period can be improved by increasing the separation between the two mesh layers (without affecting transmittance). This double-layer mesh consists of two layers of square aluminum mesh separated by a quartz-glass substrate. By increasing the substrate's optical thickness from zero to λ/4  of the shielding band's upper frequency, the shielding of the double-layer mesh improves considerably, owing to the increased reflectivity of the double-layer mesh with increasing separation in the low-frequency band. A Ku-band shielding effectiveness of over 32 dB is observed for the double-layer mesh with a normalized visible transmittance greater than 91%. It is found that the electromagnetic shielding effectiveness is enhanced by over 7 dB (80.0% energy attenuation) across the Ku-band, compared with that of a single-layer mesh, while the optical transmittances are almost identical for both tested structures. Such an enhancement permits the design of high-transparency optical elements with stronger microwave shielding that can be achieved using single-layer metallic mesh.
Recovery of image distorted by turbulent atmosphere using phase-conjugate image generated by difference frequency generation
Authors: Zou Xingquan , Hong Pengda , Ding Yujie J.
Published: December 2014

We demonstrate dynamic recovery of blurred images caused by atmospheric turbulence. In particular, using a phase-conjugate wave generated by a second-order nonlinear crystal or composite, we restore the original quality of the image after the optical radiation forming the image propagates through the turbulent atmosphere. One of the key elements for our experiment is a rotating phase plate being placed in the beam path for simulating turbulent atmosphere. Using the nonlinear composite, we demonstrate that the image recovery is insensitive to the polarization of the optical radiation forming the image.
Low electric-field driven ultrahigh electrostrains in Sb-substituted (Na,K)NbO3 lead-free ferroelectric ceramics
Authors: Fu Jian , Zuo Ruzhong , Qi He , Zhang Chen , Li Jingfeng , Li Longtu
Published: December 2014

Lead-free (Na0.52K0.48)(Nb1−ySby)O3 (NKNSy) ferroelectric ceramics were reported to exhibit an ultrahigh electrostrain (dynamic d33* (=S/E) of 800–1100 pm/V) in a relatively low driving electric field range (1–4 kV/mm). As evidenced by in-situ synchrotron x-ray diffraction and dielectric measurements, the mechanism of generating large strains was ascribed to both the low-field induced reversible rhombohedral-monoclinic phase transition (1–2 kV/mm) and the enhanced domain switching (2–4 kV/mm) owing to the normal to relaxor phase transformation, which contribute to ∼62% and ∼38% of the total strain, respectively. The results indicate that the NKNSy compositions would have excellent potentials for applications of lead-free actuator ceramics.
Molecular beam epitaxial growth and characterization of Bi2Se3/II-VI semiconductor heterostructures
Authors: Chen Zhiyi , Garcia Thor Axtmann , Hernandez-Mainet Luis C. , Zhao Lukas , Deng Haiming , Krusin-Elbaum Lia , Tamargo Maria C.
Published: December 2014

Surfaces of three-dimensional topological insulators (TIs) have been proposed to host quantum phases at the interfaces with other types of materials, provided that the topological properties of interfacial regions remain unperturbed. Here, we report on the molecular beam epitaxy growth of II-VI semiconductor–TI heterostructures using c-plane sapphire substrates. Our studies demonstrate that Zn0.49Cd0.51Se and Zn0.23Cd0.25Mg0.52Se layers have improved quality relative to ZnSe. The structures exhibit a large relative upward shift of the TI bulk quantum levels when the TI layers are very thin (∼6nm), consistent with quantum confinement imposed by the wide bandgap II-VI layers. Our transport measurements show that the characteristic topological signatures of the Bi2Se3 layers are preserved.
Localized heating of electrons in ionization zones: Going beyond the Penning-Thornton paradigm in magnetron sputtering
Authors: Anders André
Published: December 2014

The fundamental question of how energy is supplied to a magnetron discharge is commonly answered by the Penning-Thornton paradigm invoking secondary electrons. Recently, Huo and coworkers (Plasma Sources Sci. Technol. 22, 045005 (2013)) used a global discharge model to show that electron heating in the electric field of the magnetic presheath is dominant over heating by secondary electrons. In this contribution, this concept is applied locally taking into account the electric potential structure of ionization zones. Images of ionization zones can and should be interpreted as diagrams of the localization of high electric potential and related electron energy.
Effective medium model for the spectral properties of nanoporous gold in the visible
Authors: Jalas D. , Canchi R. , Petrov A. Yu. , Lang S. , Shao L. , Weissmüller J. , Eich M.
Published: December 2014

The spectral properties of nanoporous gold are distinguished by two peaks in the transmission spectrum. Unlike earlier works, we do not attribute the peaks in the transmission to two separate localized plasmon resonances. Instead we show that the spectral shape can be understood as that of diluted gold with a spectrally narrow dip in transmission that arises from the averaged electric field approaching zero. Thus, the transmission characteristics are rather featured by a dip in one broad transmission curve than by two distinct peaks. Nanoporous gold is approximated by the effective medium model of a cubic grid of gold wires.
Structure and magnetic properties of the perovskite YCo0.5Fe0.5O3
Authors: Wei Yingfen , Gui Hong , Zhao Zhenjie , Li Junrui , Liu Yong , Xin Shengwei , Li Xiaohong , Xie Wenhui
Published: December 2014

Y Co0.5Fe0.5O3, in a structure of perovskite, has been successfully prepared with citrate precursors at 950-1100 °C in air by the sol-gel method. The X-ray diffraction patterns show that the samples are orthorhombic within the space group Pnma, where the Co and Fe ions are disordered at the 4b crystallographic sites. The crystal structure refinement undertaken by the Rietveld method has shown that the distortion of Co(Fe)O6 octahedra are large, where the ratio of Co/Fe-O bonding length along a axis to that in the bc plane is about 1.07. Such a large crystal lattice distortion implies a strong lattice-magnetism coupling, which may be utilized in the magnetoelectric devices. Magnetic measurement indicates that the Y Co0.5Fe0.5O3 is antiferromagnetic but showing weak ferromagnetism. We find that Fe3+ ions are in high-spin states, while Co3+ ions are in low-spin states which do not contribute to the magnetism. Both Fe3+ and Co3+ ions are not Jahn-Teller activated although the lattice distortion is large.
Birefringent phononic structures
Authors: Psarobas I. E. , Exarchos D. A. , Matikas T. E.
Published: December 2014

Within the framework of elastic anisotropy, caused in a phononic crystal due to low crystallographic symmetry, we adopt a model structure, already introduced in the case of photonic metamaterials, and by analogy, we study the effect of birefringence and acoustical activity in a phononic crystal. In particular, we investigate its low-frequency behavior and comment on the factors which determine chirality by reference to this model.
Diversity and consistency: a case study of regionalised clinical placements for medical students
Authors: Casey Mavourneen G. , David Michael , Eley Diann
Published: December 2014

Objective A major challenge for medical schools is the provision of clinical skills training for increasing student numbers. This case study describes the expansion of the clinical school network at The University of Queensland (UQ). The purpose of the study was to investigate consistency in medical education standards across a regional clinical teaching network, as measured by academic performance. Methods A retrospective analysis of academic records for UQ medical students (n = 1514) completing clinical rotations (2009–2012) was performed using analysis of covariance (ANCOVA) for comparisons between clinical school cohorts and linear mixed-effects modelling (LEM) to assess predictors of academic performance. Results In all, 13 036 individual clinical rotations were completed between 2009 and 2012. ANCOVA found no significant differences in rotation grades between the clinical schools except that Rural Clinical School (RCS) cohorts achieved marginally higher results than non-RCSs in the general practice rotation (5.22 vs 5.10–5.18; P = 0.03) and on the final clinical examination (objective structured clinical examination; 5.27 vs 5.01–5.09; P < 0.01). LEM indicated that the strongest predictor of academic performance on clinical rotations was academic performance in the preclinical years of medical school (β = 0.38; 95% confidence interval 0.35–0.41; P < 0.001). Conclusions The decentralised UQ clinical schools deliver a consistent standard of clinical training for medical students in all core clinical rotations across a range of urban, regional and rural clinical settings. Further research is required to monitor the costs versus benefits of regionalised clinical schools for students, local communities and regional healthcare services. What is known about the topic? To help meet the demand of increasing numbers of students, Australian medical schools locate clinical training outside the traditional tertiary hospitals. However the viability of maintaining teaching standards across regional and rural locations is uncertain. What does this paper add? Maintaining teaching standards outside established urban teaching hospitals and across a diverse range of urban, regional and rural clinical settings is viable. What are the implications for practitioners? Decentralised clinical teaching networks provide consistent quality of clinical placements while diversifying exposure to different patient populations and clinical environments. These important outcomes may not only alleviate the strain on clinical teaching resources, but also help address the maldistribution of doctors in Australia.
A better way to do this? Views of mental health nursing directors about preparation for mental health nursing practice
Authors: Happell Brenda
Published: December 2014

Objective Nursing directors in mental health services hold important leadership positions that include responsibility for the nursing workforce. The comprehensive or generalist approach to undergraduate nursing education consistently poses significant recruitment problems. Specialisation in mental health within Bachelor of Nursing programs has been suggested as a potential solution. This paper presents the views and opinions of mental health nursing directors regarding undergraduate specialisation. Methods A qualitative exploratory study was undertaken. Thirteen nursing directors from Queensland Mental Health Services participated in an in-depth telephone interview. The data were analysed thematically. Results Nursing directors were very supportive of specialisation in mental health at the undergraduate level. Thematic analysis revealed four main themes: perceived advantages of the specialist stream; knowledge and experience; increased recruitment; and commitment. Conclusions Nursing directors are important stakeholders in educational preparation for practice in mental health settings. The research participants described many potential benefits to undergraduate specialisation. Their voice provides an important contribution to this issue. What is known about the topic? The current model of nurse education in Australia aims to prepare graduates for practice in a broad range of healthcare settings with specialisation occurring at the postgraduate level. Mental health nursing is identified as one of the least popular career options for nursing graduates, and mental health services struggle to recruit sufficient graduates for their nursing workforce; this is attributed, at least in part, to the current model of education. What does this paper add? This paper gives voice to the perspectives of nursing directors from the mental health service delivery sector about the educational preparation for nursing practice in mental health. Nursing directors support the introduction of specialist preparation in mental health nursing at the undergraduate level. A more skilled and committed workforce is seen as contributing to addressing current recruitment problems. What are the implications for practitioners? The educational preparation for nursing graduates for mental health practice impacts significantly on nursing leaders, and their perspective is essential in addressing the debate. Mental health nursing directors need to be formally recognised as key stakeholders in the preparation of nursing graduates.
A systems life cycle approach to managing the radiology profession: an Australian perspective
Authors: Taba Seyedamir Tavakoli , Atkinson Simon Reay , Lewis Sarah , Chung Kon Shing Kenneth , Hossain Liaquat
Published: December 2014

Objective Although the medical system has expanded considerably over the past two decades in almost all countries, so too has the demand for health care. The radiology specialisation may be an early system indicator, being especially sensitive to changes in supply and demand in both rural and urban environments. The question is whether the new policies of increasing the number of radiologists can be a proper long-term solution for the imbalance of workforce supply and demand or not. Methods Using system dynamics modelling, we present our integrated descriptive models for the supply and demand of Australian radiologists to find the actual gap. Followed by this, we pose a prescriptive model for the supply in order to lessen the identified imbalance between supply and demand. Our system dynamics models compare the demand and supply of Australian radiologists over 40 years between 2010 and 2050. Results The descriptive model shows that even if the radiology training program grows at a higher rate than the medical training growth rate and its own historical growth, the system will never be able to meet demand. The prescriptive model also indicates that although changing some influential factors (e.g the intake rate) reduces the level of imbalance, the system will still stay unstable during the study period. Conclusion We posit that Australia may need to design a new system of radiology provision to meet future demands for high-quality medical radiation services. We also suggest some strategies, such as greater development of radiographers’ role, are critical for enabling sustainable change over time. What is known about the topic? Long-term workforce planning for medical services at the national level has been very challenging for policy makers of the 21st century. The current demographic imbalance in the supply and demand of the Australian radiologist workforce makes it difficult to plan the effects of extra inflow of radiology students over time. What does this paper add? This paper discovers the current situation facing the Australian Radiology profession and identifies all the factors that influence the long-term matching of radiologist workforce supply and demand. This Australian case study adds to the current literature of medical workforce planning and its challenges. Moreover, this paper answers how the problem of workforce imbalance can be solved through a sustainable change over time. What are the implications for practitioners? Conventional responses in Australia and many developed countries in response to radiological services demand have been to increase the number of radiologists. However, our models and analyses show that this is not an all-inclusive long-term solution: merely increasing the number of radiologists will not result in a balance between supply and demand.
Effects of physically effective neutral detergent fibre content on dry-matter intake, digestibility and chewing activity in beef cattle fed total mixed ration
Authors: Park Jae Hyun , Kim Kyoung Hoon , Park Pyo Jam , Jeon Byong Tae , Oh Mi Rae , Jang Se Yeong , Sung Si Heung , Moon Sang Ho
Published: December 2014

Our aim in this study was to determine the effects of physically effective neutral detergent fibre (peNDF) in a total mixed ration (TMR) on feed intake, digestibility and chewing activity in beef cattle. The experiment had a replicated 3 × 3 Latin square desig, using three fattening Hanwoo (Bos taurus coreanae) steers with ruminal cannulas. Steers were offered one of three diets (high, medium or low peNDF content) obtained by mixing the same TMR for different periods of time (5, 13 and 25 min). peNDF content of TMR was calculated as [total chewing time/NDF intake (kg)] × dietary NDF content, and the proportion of sample dry matter (DM) collected in a ≥1.18-mm sieve is commonly used as the physical effectiveness factor in the equation. The peNDF1.18 contents of the high, medium and low diets were 25.97%, 21.10% and 17.94% (P < 0.05). In addition, the proportion of particles collected on the 19-mm, 1.18-mm, and pan sieves changed linearly with an increase of TMR mixing time. Mean particle-size distributions of diets were 11.43, 24.11, 30.70 and 33.68 for 19 mm, 8 mm, 1.18 mm and pan, respectively. Eating rate and ruminating and chewing efficiencies were significantly decreased with reduced peNDF content, and DM intake was increased significantly (P < 0.05). Lower peNDF content reduced the total number of chews significantly (P < 0.05). Total time spent chewing associated with eating was not affected by peNDF contents. Digestibility of DM, crude protein and crude fat decreased with reducing peNDF content in the diet, but there was no significant difference among the three groups. These results indicated that peNDF affects intake, digestibility and chewing activity in beef cattle. Therefore, high levels of peNDF appears to improve TMR, as it can increase efficiency and may prevent ruminal disorders in Hanwoo steer.
Effects of different doses of sodium monensin on feeding behaviour, dry matter intake variation and selective consumption of feedlot Nellore cattle
Authors: Pereira Murillo C. S. , Carrara Tássia V. B. , da Silva Juliana , Silva Diego P. , Watanabe Daniel H. M. , Tomaz Lais A. , Arrigoni Mário D. B. , Millen Danilo D.
Published: December 2014

The experiment was designed to determine the effects of different doses of sodium monensin (MON) on feeding behaviour, dry matter intake (DMI) variation and selective consumption of feedlot Nellore cattle. The experiment was a randomised complete block design, replicated 12 times, in which 60 20-month-old yearling Nellore bulls (402.52 ± 33.0 kg) were fed the following different doses of MON (expressed in mg per kg, on a DM basis) in individual pens for 84 days: 0, 9, 18, 27 and 36. The adaptation program consisted of ad libitum feeding of two adaptation diets over a period of 14 days with concentrate level increasing from 68% to 84% of diet DM. Orthogonal contrasts were used to assess linear, quadratic, cubic and quartic relationships between doses of MON and the dependent variable. As the dose of MON increased, the time spent ruminating (P < 0.01), feeding efficiency of DM (P < 0.05) and feeding efficiency of neutral detergent fibre (NDF; P < 0.05) were affected linearly during the period of adaptation. For the finishing period, as the dose of MON increased, time spent eating and ruminating, and feeding efficiency of DM were affected quadratically (P < 0.05), in which animals fed 9 ppm of MON presented better feeding efficiency of DM. Thus, as animals fed 9 ppm of MON presented better feeding efficiency of DM and NDF during the adaptation and finishing periods, it should be the dose of choice for feedlot Nellore cattle.
Evolution of the syphilis epidemic among men who have sex with men
Authors: Solomon Marc M. , Mayer Kenneth H.
Published: December 2014

Syphilis has existed for millenni, but its epidemiology was only recently linked to men who have sex with men (MSM) after the introduction of penicillin in the 1940s; the syphilis epidemic became concentrated within the MSM community in subsequent decades. The HIV/AIDS epidemic in the 1980s led to a surge of new syphilis cases and revealed the potentiation between HIV and syphilis, as evidenced by a shift in the natural history of neurosyphilis. In response, MSM revolutionised their sexual behaviour by implementing community-driven seroadaptive strategies to stem HIV transmission. The Centers for Disease Control in the US called for the elimination of syphilis in the late 1990s since the rates had fallen sharply but this effort was overtaken by a resurgence of global outbreaks among MSM in the 2000s, many of which were linked to methamphetamine use and sexual networking websites. Syphilis remains highly prevalent today, especially among MSM and individuals infected with HIV, and it continues to present a significant public health conundrum. Innovative syphilis prevention strategies are warranted. MSM engaging in high-risk behaviour such as condomless anal receptive intercourse, sex with multiple partners or recreational drug use should be routinely screened for syphilis infection; they should also be counselled about the limits of seroadaptive behaviours and HIV pre-exposure prophylaxis as they relate to syphilis transmission.
Large-scale topology and the default mode network in the mouse connectome
Authors: Stafford James M. , Jarrett Benjamin R. , Miranda-Dominguez Oscar , Mills Brian D. , Cain Nicholas , Mihalas Stefan , Lahvis Garet P. , Lattal K. Matthew , Mitchell Suzanne H. , David Stephen V. , Fryer John D. , Nigg Joel T. , Fair Damien A.
Published: December 2014

Significance

Noninvasive brain imaging holds great promise for expanding our capabilities of treating human neurologic and psychiatric disorders. However, key limitations exist in human-only studies, and the ability to use animal models would greatly advance our understanding of human brain function. Mice offer sophisticated genetic and molecular methodology, but correlating these data to functional brain imaging in the mouse brain has remained a major hurdle. This study is the first, to our knowledge, to use whole-brain functional imaging to show large-scale functional architecture with structural correlates in the mouse. Perhaps more important is the finding of conservation in brain topology and default network among rodents and primates, thereby clearing the way for a bridge measurement between human and mouse models.
Interspecific introgressive origin of genomic diversity in the house mouse
Authors: Liu Kevin J. , Steinberg Ethan , Yozzo Alexander , Song Ying , Kohn Michael H. , Nakhleh Luay
Published: December 2014

Significance

The mouse has been one of the main mammalian model organisms used for genetic and biomedical research. Understanding the evolution of house mouse genomes would shed light not only on genetic interactions and their interplay with traits in the mouse but would also have significant implications for human genetics and health. Analysis using a recently developed statistical method shows that the house mouse genome is a mosaic that contains previously unrecognized contributions from a different mouse species. We traced these contributions to ancient and recent interbreeding events. Our findings reveal the extent of introgression in an important mammalian genome and provide an approach for genome-wide scans of introgression in other eukaryotic genomes.
Phytochrome controls alternative splicing to mediate light responses in
Arabidopsis
Authors: Shikata Hiromasa , Hanada Kousuke , Ushijima Tomokazu , Nakashima Moeko , Suzuki Yutaka , Matsushita Tomonao
Published: December 2014

Significance

Plants adapt to their fluctuating environment by monitoring surrounding light conditions through several photoreceptors, such as phytochrome. It is widely believed that upon absorbing red light, phytochrome induces plant light responses by regulating the transcription of numerous target genes. In this study, we provide clear evidence that phytochrome controls not only transcription, but also alternative splicing in
Arabidopsis
. We reveal that 6.9% of the annotated genes in the
Arabidopsis
genome undergo rapid changes in their alternative splicing patterns in a red light- and phytochrome-dependent manner. Our results demonstrate that phytochrome simultaneously regulates two different aspects of gene expression, namely transcription and alternative splicing to mediate light responses in plants.
Bifurcation analysis of single-cell gene expression data reveals epigenetic landscape
Authors: Marco Eugenio , Karp Robert L. , Guo Guoji , Robson Paul , Hart Adam H. , Trippa Lorenzo , Yuan Guo-Cheng
Published: December 2014

Significance

Characterization of cellular heterogeneity and hierarchy are important tasks in developmental biology and may help overcome drug resistance in treatment of cancer and other diseases. Single-cell technologies provide a powerful tool for detecting rare cell types and cell-fate transition events, whereas traditional gene expression profiling methods can be used only to measure the average behavior of a cell population. However, the lack of suitable computational methods for single-cell data analysis has become a bottleneck. Here we present a method with the focuses on automatically detecting multilineage transitions and on modeling the associated changes in gene expression patterns. We show that our method is generally applicable and that its applications provide biological insights into developmental processes.
The role of self-interest in elite bargaining
Authors: LeVeck Brad L. , Hughes D. Alex , Fowler James H. , Hafner-Burton Emilie , Victor David G.
Published: December 2014

Significance

Humans frequently act contrary to their self-interest and reject low offers in bargaining games. Some evidence suggests that elites, however, are much more rational and self-interested, but this hypothesis has never been directly tested in bargaining games. Using a unique sample of US policy and business elites, we find the opposite. Compared with typical convenience samples, elites are even more prone to act contrary to self-interest by rejecting low offers when bargaining. Appearing to anticipate this fact, elites also make higher offers. This may help to explain why policy elites, such as the diplomats who negotiate treaties on topics like global warming, pay close attention to distributional concerns even though such concerns have been a perennial source of policy gridlock.
Nonredundant protective properties of FPR2/ALX in polymicrobial murine sepsis
Authors: Gobbetti Thomas , Coldewey Sina M. , Chen Jianmin , McArthur Simon , le Faouder Pauline , Cenac Nicolas , Flower Roderick J. , Thiemermann Christoph , Perretti Mauro
Published: December 2014

Significance

Sepsis defines a syndrome with poor clinical management characterized by overlapping phases of excessive inflammation temporally aligned with an immunosuppressed state. We define an endogenous pathway centered on formyl-peptide receptor 2/3 (Fpr2/3)—ortholog to human FPR2/ALX (receptor for lipoxin A4)—that protects the host against polymicrobial sepsis. Using null mice and proof-of-concept experiments with a peptide–agonist, we demonstrate how engagement of Fpr2/3 is crucial to enact nonredundant functions that span from control of cell recruitment and phagocytosis, modulation of soluble mediator generation, to containment of bacteremia, thus preventing spreading to vital organs and opening new opportunities to manipulate the host response in sepsis.
Licensed human natural killer cells aid dendritic cell maturation via TNFSF14/LIGHT
Authors: Holmes Tim D. , Wilson Erica B. , Black Emma V. I. , Benest Andrew V. , Vaz Candida , Tan Betty , Tanavde Vivek M. , Cook Graham P.
Published: December 2014

Significance

As well as having potent cytotoxic activity, natural killer (NK) cells have a regulatory role and interactions between NK cells and dendritic cells (DCs) aid DC maturation and adaptive immunity. However, the mechanisms underpinning NK–DC cross-talk are poorly defined. We show that tumor cells induce rapid production of the cytokine TNF superfamily member 14 (TNFSF14) in human NK cells and that these NK cells induce DC maturation in a TNFSF14-dependent manner. The synergistic activity of NK cell activation receptors in licensed NK cells couples the release of cytotoxic granules to TNFSF14 production. Thus, NK cell activation by tumor cells is linked to the initiation of adaptive immunity via TNFSF14-mediated NK–DC cross-talk.
STAT3 promotes survival of mutant photoreceptors in inherited photoreceptor degeneration models
Authors: Jiang Ke , Wright Katherine L. , Zhu Ping , Szego Michael J. , Bramall Alexa N. , Hauswirth William W. , Li Qiuhong , Egan Sean E. , McInnes Roderick R.
Published: December 2014

Significance

There is a great need for a therapy for inherited photoreceptor degenerations (IPDs) that would be effective irrespective of the affected gene. A treatment that slows photoreceptor (PR) death, even by 10–20%, could greatly extend the years of useful vision of patients with IPD for whom specific treatment is not available. Up-regulation of
Stat3
has been reported in the retinas of many IPD models, but whether
Stat3
expression is neuroprotective in mutant PRs has not been established. We show that
Stat3
plays a strong prosurvival role in two distinct IPD models and that further augmentation of PR
Stat3
expression slows PR death. These findings suggest the potential of
Stat3
augmentation, for example, by recombinant adenoassociated virus (rAAV) vector-mediated gene therapy, as a treatment for IPDs.
Laser altimetry reveals complex pattern of Greenland Ice Sheet dynamics
Authors: Csatho Beata M. , Schenk Anton F. , van der Veen Cornelis J. , Babonis Gregory , Duncan Kyle , Rezvanbehbahani Soroush , van den Broeke Michiel R. , Simonsen Sebastian B. , Nagarajan Sudhagar , van Angelen Jan H.
Published: December 2014

Significance

We present the first detailed reconstruction of surface elevation changes of the Greenland Ice Sheet from NASA’s laser altimetry data. Time series at nearly 100,000 locations allow the characterization of ice sheet changes at scales ranging from individual outlet glaciers to larger drainage basins and the entire ice sheet. Our record shows that continuing dynamic thinning provides a substantial contribution to Greenland mass loss. The large spatial and temporal variations of dynamic mass loss and widespread intermittent thinning indicate the complexity of ice sheet response to climate forcing, strongly enforcing the need for continued monitoring at high spatial resolution and for improving numerical ice sheet models.
TSPAN12 is a critical factor for cancer–fibroblast cell contact-mediated cancer invasion
Authors: Otomo Ryo , Otsubo Chihiro , Matsushima-Hibiya Yuko , Miyazaki Makoto , Tashiro Fumio , Ichikawa Hitoshi , Kohno Takashi , Ochiya Takahiro , Yokota Jun , Nakagama Hitoshi , Taya Yoichi , Enari Masato
Published: December 2014

Significance

Cancer-associated fibroblasts (CAFs) are abundant and promote cancer proliferation, invasion, and metastasis. Mutations in the p53 gene and decreased p53 expression are often detected in CAFs, and a dysfunction in p53 in CAFs contributes to cancer progression. However, how host-derived p53 influences cancer cells remains unclear. We herein established coculture systems to monitor enhancements in invasiveness and proliferation elicited by p53-depleted fibroblasts and demonstrated that tetraspanin 12 (TSPAN12), identified as a p53-regulated gene, was required for these processes through the contact of cancer cells with stromal fibroblasts and β-catenin–mediated CXC chemokine ligand 6 (CXCL6) secretion. These results suggest that antibodies against TSPAN12 and CXCL6 may be effective therapeutic agents for cancer.