bluuebunny/crossref_metadata_2025 huggingface dataset:
Sintered magnetic cores of high Bs Fe84.3Si4B8P3Cu0.7 nano-crystalline alloy with a lamellar microstructure
Authors: Zhang Yan , Sharma Parmanand , Makino Akihiro
Published: February 2014

Fabrication of bulk cores of nano-crystalline Fe84.3Si4B8P3Cu0.7 alloy with a lamellar type of microstructure is reported. Amorphous ribbon flakes of size ∼1.0–2.0 mm were compacted in the bulk form by spark plasma sintering technique at different sintering temperatures. High density (∼96.4%) cores with a uniform nano-granular structure made from α-Fe (∼31 nm) were obtained. These cores show excellent mechanical and soft magnetic properties. The lamellar micro-structure is shown to be important in achieving significantly lower magnetic core loss than the non-oriented silicon steel sheets, commercial powder cores and even the core made of the same alloy with finer and randomly oriented powder particles.
Investigation on the pyroelectric property of polycrystalline GdMnO3
Authors: Zhang X. , Zhao Y. G. , Cui Y. F. , Ye L. D. , Zhao D. Y. , Li P. S. , Wang J. W. , Zhu M. H. , Zhang H. Y. , Rao G. H.
Published: February 2014

Pyroelectric property of orthorhomic GdMnO3 polycrystalline samples was investigated. Two pyrocurrent peaks were observed with the sharp one near 20 K and the broad one at around 120 K. The dependences of these two peaks on magnetic field, heating rate, and poling voltage were explored systematically. The sharp peak is related to the ferroelectric transition, while the behavior of the broad one corresponds to dipole reorientation. Some key pyroelectric features are proposed to separate the spin-induced ferroelectricity from other effects. This work is helpful for understanding the pyroelectric property of multiferroic materials.
Computation of radiative heat transport across a nanoscale vacuum gap
Authors: Budaev Bair V. , Bogy David B.
Published: February 2014

Radiation heat transport across a vacuum gap between two half-spaces is studied. By consistently applying only the fundamental laws of physics, we obtain an algebraic equation that connects the temperatures of the half-spaces and the heat flux between them. The heat transport coefficient generated by this equation for such structures matches available experimental data for nanoscale and larger gaps without appealing to any additional specific mechanisms of energy transfer.
Non-volatile, electric control of magnetism in Mn-substituted ZnO
Authors: Wang X. L. , Shao Q. , Leung C. W. , Lortz R. , Ruotolo A.
Published: February 2014

We show that the magnetic properties of a dilute semiconductor oxide can be altered in a reversible and non-volatile manner by the application of an electric field. The selected ferromagnetic oxide was manganese-substituted zinc oxide. Bipolar resistive memory switching was induced in the film sandwiched between two metallic electrodes. The bistable switching of the resistive state was accompanied by a bistable switching of the magnetic moment. The scalability of the system was investigated by fabricating devices with lateral size down to 400 nm.
Correlative analysis of the in situ changes of carrier decay and proton induced photoluminescence characteristics in chemical vapor deposition grown GaN
Authors: Gaubas E. , Ceponis T. , Jasiunas A. , Kovalevskij V. , Meskauskaite D. , Pavlov J. , Remeikis V. , Tekorius A. , Vaitkus J.
Published: February 2014

In order to evaluate carrier densities created by 1.6 MeV protons and to trace radiation damage of the 2.5 μm thick GaN epi-layers grown by metalorganic chemical vapor deposition technique, a correlation between the photoconductivity transients and the steady-state photoluminescence spectra have been examined. Comparison of luminescence spectra induced by proton beam and by laser pulse enabled us to evaluate the efficiency of a single proton generation being of 1 × 107 cm−3 per 1.6 MeV proton and 40 carrier pairs per micrometer of layer depth. This result indicates that GaN layers can be an efficient material for detection of particle flows. It has been demonstrated that GaN material can also be a rather efficient scintillating material within several wavelength ranges.
Smart microgrid operational planning considering multiple demand response programs
Authors: Zakariazadeh Alireza , Jadid Shahram
Published: February 2014

Microgrid (MG) is one of the important blocks in the future smart distribution systems. The scheduling pattern of MGs affects distribution system operation. Also, the optimal scheduling of MGs will result in reliable and economical operation of distribution system. In this paper, an operational planning model of a MG which considers multiple demand response programs is proposed. In the proposed approach, all types of loads can participate in demand response programs which will be considered in either energy or reserve scheduling. Also, the renewable distributed generation uncertainty is covered by reserve provided by both Distributed Generations (DGs) and responsive loads. The novelty of this paper is the demand side participation in energy and reserve scheduling, simultaneously. Furthermore, the energy and reserve scheduling is proposed for day-ahead and real-time. The proposed model was tested on a typical MG system and the results show that running demand response programs will reduce total operation cost of MG and cause more efficient use of resources.
The spin-dependent transport of Co-encapsulated Si nanotubes contacted with Cu electrodes
Authors: Guo Yan-Dong , Yan Xiao-Hong , Xiao Yang
Published: February 2014

Unlike carbon nanotubes, silicon ones are hard to form. However, they could be stabilized by metal-encapsulation. Using first-principles calculations, we investigate the spin-dependent electronic transport of Co-encapsulated Si nanotubes, which are contacted with Cu electrodes. For the finite tubes, as the tube-length increases, the transmission changes from spin-unpolarized to spin-polarized. Further analysis shows that, not only the screening of electrodes on Co's magnetism but also the spin-asymmetric Co-Co interactions are the physical mechanisms. As Cu and Si are the fundamental elements in semiconductor industry, our results may throw light on the development of silicon-based spintronic devices.
Photophysiological responses of marine diatoms to elevated CO2 and decreased pH: a review
Authors: Gao Kunshan , Campbell Douglas A.
Published: February 2014

Diatoms dominate nearly half of current oceanic productivity, so their responses to ocean acidification are of general concern regarding future oceanic carbon sequestration. Community, mesocosm and laboratory studies show a range of diatom growth and photophysiological responses to increasing pCO2. Nearly 20 studies on effects of elevated pCO2 on diatoms have shown stimulations, no effects or inhibitions of growth rates. These differential responses could result from differences in experimental setups, cell densities, levels of light and temperature, but also from taxon-specific physiology. Generally, ocean acidification treatments of lowered pH with elevated CO2 stimulate diatom growth under low to moderate levels of light, but lead to growth inhibition when combined with excess light. Additionally, diatom cell sizes and their co-varying metabolic rates can influence responses to increasing pCO2 and decreasing pH, although cell size effects are confounded with taxonomic specificities in cell structures and metabolism. Here we summarise known diatom growth and photophysiological responses to increasing pCO2 and decreasing pH, and discuss some reasons for the diverse responses observed across studies.
Functional epigenetics approach identifies BRM/SMARCA2 as a critical synthetic lethal target in BRG1-deficient cancers
Authors: Hoffman Gregory R. , Rahal Rami , Buxton Frank , Xiang Kay , McAllister Gregory , Frias Elizabeth , Bagdasarian Linda , Huber Janina , Lindeman Alicia , Chen Dongshu , Romero Rodrigo , Ramadan Nadire , Phadke Tanushree , Haas Kristy , Jaskelioff Mariela , Wilson Boris G. , Meyer Matthew J. , Saenz-Vash Veronica , Zhai Huili , Myer Vic E. , Porter Jeffery A. , Keen Nicholas , McLaughlin Margaret E. , Mickanin Craig , Roberts Charles W. M. , Stegmeier Frank , Jagani Zainab
Published: February 2014

Significance

Mammalian SWI/SNF (mSWI/SNF) alterations are highly prevalent, now estimated to occur in 20% of cancers. The inactivating nature of mSWI/SNF mutations presents a challenge for devising strategies to target these epigenetic lesions. By performing a comprehensive pooled shRNA screen of the epigenome using a unique deep coverage design shRNA (DECODER) library across a large cancer cell line panel, we identified that
BRG1/SMARCA4
mutant cancer cells are highly sensitive to
BRM/SMARCA2
depletion. Our study provides important mechanistic insight into the BRM/BRG1 synthetic lethal relationship, shows this finding translates in vivo, and highlights BRM as a promising therapeutic target for the treatment
BRG1
-mutant cancers.
Are Well-Child Visits a Risk Factor for Subsequent Influenza-Like Illness Visits?
Authors: Simmering Jacob E. , Polgreen Linnea A. , Cavanaugh Joseph E. , Polgreen Philip M.
Published: February 2014

Objective.

To determine whether well-child visits are a risk factor for subsequent influenza-like illness (ILI) visits within a child's family. DESIGN. Retrospective cohort.

Methods.

Using data from the Medical Expenditure Panel Survey from the years 1996-2008, we identified 84,595 families. For each family, we determined those weeks in which a well-child visit or an ILI visit occurred. We identified 23,776 well-child-visit weeks and 97,250 ILI-visit weeks. We fitted a logistic regression model, where the binary dependent variable indicated an ILI clinic visit in a particular week. Independent variables included binary indicators to denote a well-child visit in the concurrent week or one of the previous 2 weeks, the occurrence of the ILI visit during the influenza season, and the presence of children in the family in each of the age groups 0–3, 4–7, and 8–17 years. Socioeconomic variables were also included. We also estimated the overall cost of well-child-exam-related ILI using data from 2008.

Results.

We found that an ILI office visit by a family member was positively associated with a well-child visit in the same or one of the previous 2 weeks (odds ratio, 1.54). This additional risk translates to potentially 778,974 excess cases of ILI per year in the United States, with a cost of $500 million annually.

Conclusions.

Our results should encourage ambulatory clinics to strictly enforce infection control recommendations. In addition, clinics could consider time-shifting of well-child visits so as not to coincide with the peak of the influenza season.
No universal minimum-mass extrasolar nebula: evidence againstin situaccretion of systems of hot super-Earths
Authors: Raymond Sean N. , Cossou Christophe
Published: February 2014

It has been proposed that the observed systems of hot super-Earths formed in situ from high-mass discs. By fitting a disc profile to the entire population of Kepler planet candidates, Chiang & Laughlin constructed a ‘minimum-mass extrasolar nebula’ with surface density profile Σ ∝ r−1.6. Here, we use multiple-planet systems to show that it is inconsistent to assume a universal disc profile. Systems with 3–6 low-mass planets (or planet candidates) produce a diversity of minimum-mass discs with surface density profiles ranging from Σ ∝ r−3.2 to Σ ∝ r0.5 (5th–95th percentile). By simulating the transit detection of populations of synthetic planetary systems designed to match the properties of observed super-Earth systems, we show that a universal disc profile is statistically excluded at high confidence. Rather, the underlying distribution of minimum-mass discs is characterized by a broad range of surface density slopes. Models of gaseous discs can only explain a narrow range of slopes (roughly between r0 and r−1.5). Yet accretion of terrestrial planets in a gas-free environment preserves the initial radial distribution of building blocks. The known systems of hot super-Earths must therefore not represent the structure of their parent gas discs and cannot have predominantly formed in situ. We instead interpret the diversity of disc slopes as the imprint of a process that re-arranged the solids relative to the gas in the inner parts of protoplanetary discs. A plausible mechanism is inward type 1 migration of Mars- to Earth-mass planetary embryos, perhaps followed by a final assembly phase.
Study of the Intracluster and Intergalactic Medium in the Sculptor Supercluster with Suzaku
Authors: Sato Kosuke , Kelley Richard L. , Takei Yoh , Tamura Takayuki , Yamasaki Noriko Y. , Ohashi Takaya , Gupta Anjali , Galeazzi Massimiliano
Published: February 2014

We studied the high-temperature plasma in the direction of the Sculptor supercluster at $z =$ 0.108 with Suzaku. Suzaku carried out four observations in the supercluster: namely, A 2811, A 2811 offset, A 2804, A 2801 regions in 2005 November–December, including the regions beyond the virial radii of these clusters. The spectra taken in regions outside of the virial radii of the member clusters were used as background that included both of the Galactic and Cosmic X-ray Background (CXB) components. Temperature and metal abundance profiles were determined to the virial radii of the member clusters, and we then searched for oxygen line emission in the region outside of the virial radii of the clusters. As a result, the temperature of the clusters decreased toward the virial radii, and the spectral fits for the filament region did not require any extra component other than the Galactic and CXB components. We constrained the intensities of the OVII and OVIII lines to be less than 8.1 and 5.1 $\times$ 10$^{-8}$ photons cm$^{-2}\ $s$^{-1}\ $arcmin$^{-2}\ $, respectively, as 2$\ \sigma$ upper limits in the filament region. The intensity of OVII indicates $n_{\rm H}$$<$ 1.6 $\times$ 10$^{-5}\ $cm$^{-3}$ ($Z/$0.1$\ Z_{\odot}$)$^{-1/2}$($L/$25 Mpc)$^{-1/2}$, which corresponds to an over density of $\delta$$<$ 60($Z/$0.1$\ Z_{\odot}$)$^{-1/2}$($L/$25 Mpc)$^{-1/2}$.
Cosmic Star-Formation Activity at z = 2.2 Probed by H α Emission-Line Galaxies
Authors: Tadaki Ken-ichi , Kodama Tadayuki , Koyama Yusei , Hayashi Masao , Tanaka Ichi , Tokoku Chihiro
Published: February 2014

We present a pilot narrow-band survey of H$\alpha$ emitters at z  $=$ 2.2 in the Great Observatories Origins Deep Survey North (GOODS-N) field with MOIRCS instrument on the Subaru Telescope. The survey reached a 3$\ \sigma$ limiting magnitude of 23.6 (NB209), which corresponds to a 3$\ \sigma$ limiting line flux of 2.5 $\times$ 10$^{-17}\ $erg s$^{-1}\ $cm$^{-2}$ over a 56 arcmin$^2$ contiguous area (excluding a shallower area). From this survey, we have identified eleven H$\alpha$ emitters and one AGN at z  $=$ 2.2 on the basis of narrow-band excesses and photometric redshifts. We obtained spectra for seven out of the new objects, including one AGN; also, an emission line above 3$\ \sigma$ was detected from all of them. We estimated star-formation rates (SFR) and stellar masses ($M_{\mathrm{star}}$) for individual galaxies. The average SFR and $M_{\mathrm{star}}$ are 27.8$\ M_{\odot}\ $yr$^{-1}\ $ and 4.0 $\times$ 10$^{10}\ M_\odot$, respectively. Their specific star-formation rates negatively correlate with their stellar masses. Fitting to a Schechter function yields the H$\alpha$ luminosity function with log$L$  $=$ 42.82, log$\phi$  $=$  $-$2.78, and $\alpha$  $=$  $-$1.37. The average star-formation rate density in the survey volume is estimated to be 0.31$\ M_{\odot}\ $yr$^{-1}\ $Mpc$^{-3}$ according to the Kennicutt relation between the H$\alpha$ luminosity and the star-formation rate. We compared our H$\alpha$ emitters at z  $=$ 2.2 in GOODS-N with narrow-band line emitters in other fields and clusters to see their time evolution and environmental dependence. We found that the star-formation activity is rapidly reduced from z  $=$ 2.5 to z  $=$ 0.8 in the cluster environment, while it only moderately changed in the field environment. This result suggests that the time scale of galaxy formation differs among different environments, and the star-forming activities in high density regions eventually overtake those in lower-density regions as a consequence of “galaxy-formation bias” at high redshifts.
Infrared 3–4 μm Spectroscopy of Nearby PG QSOs and AGN–Nuclear Starburst Connections in High-Luminosity AGN Populations
Authors: Imanishi Masatoshi , Ichikawa Kohei , Takeuchi Tomoe , Kawakatu Nozomu , Oi Nagisa , Imase Keisuke
Published: February 2014

We present the results of infrared $L$-band (3–4$\ \mu$m) slit spectroscopy of 30 PG QSOs at z$\lt$ 0.17, a representative sample of local high-luminosity, optically selected AGNs. The 3.3$\ \mu$m polycyclic aromatic hydrocarbon (PAH) emission feature is used to probe nuclear ($\lt$ a few kpc) starburst activity and to investigate the connections between AGNs and nuclear starbursts in PG QSOs. The 3.3$\ \mu$m PAH emission is detected in the individual spectra of 5/30 of the observed PG QSOs. We constructed a composite spectrum of PAH-undetected PG QSOs and discerned the presence of the 3.3$\ \mu$m PAH emission therein. We estimated the nuclear-starburst and AGN luminosities from the observed 3.3$\ \mu$m PAH emission and 3.35$\ \mu$m continuum luminosities, respectively, and found that the nuclear-starburst-to-AGN luminosity ratios in PG QSOs are similar to those of previously studied AGN populations with lower luminosities, suggesting that AGN–nuclear starburst connections are valid over a wide luminosity range of AGNs in the local universe. The observed nuclear-starburst-to-AGN luminosity ratios in PG QSOs with available supermassive black-hole masses are comparable to a theoretical prediction based on the assumption that the growth of a supermassive black hole is controlled by starburst-induced turbulence.
Exploring the [S$/$Fe] Behavior of Metal-Poor Stars with the S I 1.046μm Lines
Authors: Takeda Yoichi , Takada-Hidai Masahide
Published: February 2014

In an attempt of clarifying the [S$/$Fe] behavior with the run of [Fe$/$H] in the metal-poor regime, which has been a matter of debate, an extensive non-LTE analysis of near-IR S I triplet lines (multiplet 3) at 1.046$\ \mu$m was carried out for 33 selected halo/disk stars over a wide metallicity range of [Fe$/$H] $\sim-$3.7 to $\sim\ +$0.3, based on spectral data collected with IRCS$+$AO188 of the Subaru Telescope. We found evidence of a considerably large [S$/$Fe] ratio, amounting to $\sim\ +$0.7–0.8 dex at very low metallicity of [Fe$/$H] $\sim$  $-$3, which makes marked contrast with other $\alpha$-elements (Mg, Si, Ca, Ti) flatly showing a moderately supersolar [$\alpha/$Fe] of $\sim$0.3 dex. Meanwhile, a locally-flat tendency of [S$/$Fe] at $\sim\ +$0.3 is seen at $-$2.5 $\lesssim$ [Fe$/$H] $\lesssim$  $-$1.5. These results may suggest that the nature of [S$/$Fe] in metal-poor halo stars is not as simple as has been argued (i.e., neither being globally flat independent of [Fe$/$H] nor monotonically increasing with a decrease in [Fe$/$H]), but rather complicated with a local plateau around [Fe$/$H] $\sim-$2, followed by a discontinuous jump between the narrow interval of $-$3 $\lesssim$ [Fe$/$H] $\lesssim$  $-$2.5.
Sphericity Preference in Shapes of Sub-km-Sized Fast-Rotating Main-Belt Asteroids
Authors: Nakamura Tsuko , Dermawan Budi , Yoshida Fumi
Published: February 2014

Here, we report on results of statistical analyses on spin periods and shapes of main-belt asteroids (MBAs) smaller than $\ \sim\ $1 km in diameter, which were derived from lightcurve observations of a single night with the 8.2 m Subaru telescope. It is shown that, among our detected 68 MBAs giving reliable lightcurve periods, the fraction of fast-rotating asteroids (with spin periods of $\lt\ \sim\ $2.3 hr, candidates of monolithic bodies) is about 49%. In particular, statistical tests reveal with a high confidence level that, in terms of the shape (deduced from the light variation amplitude), the fast rotators belong to a population quite different from that for non fast-rotators; in other words, most of the fast-rotators show a strong trend that they are more spherical in shape than the non fast-rotator group. Consideration of several orbital and rotational evolution timescales for small asteroids in the main asteroid belt seems to indicate that the above-mentioned trend is not by coincidence, but primordial. Therefore, referring to the shape distributions of impact fragments produced in laboratory experiments, our discovered sphericity preference of small fast-rotating asteroids probably requires some spin deceleration mechanisms, which selectively worked on all elongated objects during their impact formation and/or subsequent evolution. We also note that our fast rotators are much more spherical compared to known small MBAs and near-Earth objects.
Cryogenic Volume-Phase Holographic Grisms for MOIRCS
Authors: Ebizuka Noboru , Ichiyama Kotaro , Yamada Toru , Tokoku Chihiro , Onodera Masato , Hanesaka Mai , Kodate Kashiko , Uchimoto Yuka Katsuno , Maruyama Miyoko , Shimasaku Kazuhiro , Tanaka Ichi , Yoshikawa Tomohiro , Kashikawa Nobunari , Iye Masanori , Ichikawa Takashi
Published: February 2014

We have developed high-dispersion VPH (volume phase holographic) grisms with zinc selenide (ZnSe) prisms for the cryogenic optical system of MOIRCS (Multi-Object near-InfraRed Camera and Spectrograph) for Y-, J-, H-, and K-band observations. We fabricated VPH gratings using a hologram resin. After several heat cycles at between room temperature and 120 K, the VPH gratings were assembled to grisms by gluing with two ZnSe prisms. Several heat cycles were also carried out for the grisms before being installed into MOIRCS. We measured the efficiencies of the VPH grisms in a laboratory, and found them to be 70%–82%. The performances obtained by observations of MOIRCS with the 8.2 m Subaru Telescope have been found to be very consistent with the results in the laboratory test. This is the first astronomical application of cryogenic VPH grisms.
Measuring Oxidative Gelation of Aqueous Flour Suspensions Using the Rapid Visco Analyzer
Authors: Ross Andrew S. , Bettge Arthur D. , Kongraksawech Teepakorn , Engle Douglas A.
Published: February 2014

The Rapid Visco Analyzer (RVA) was investigated as a tool to measure oxidative gelation capacity (OGC) of aqueous wheat flour suspensions. One club wheat patent flour was used to determine optimal hydration time, and 33 straight‐grade flours (representing 12 hard and 21 soft varieties) were used to observe varietal differences in OGC. A 33.3% w/w flour–water suspension was tested in the RVA at 30°C and 160 rpm for 1 min to establish the flour–water baseline viscosity, and then 65 μL of 3% H2O2 was added and the viscosity of the suspension measured at 160 rpm for a further 5 min. Flour from the club wheat showed that 20 min of prehydration was needed to observe full OGC potential. For the 33 straight‐grade flours, final RVA water baseline viscosity was correlated with Bostwick Consistometer (BC) flow (r = −0.93, P ≤ 0.01), and RVA H2O2 peak viscosity was correlated with H2O2 BC flow (r = –0.81, P ≤ 0.01). The RVA was able to differentiate H2O2‐reactive from nonreactive flours. The RVA can observe phenomena not observable with the BC method (e.g., viscosity reduction over time at constant shear rate), which can provide potentially valuable additional information about the nature of OGC in wheat flour suspensions.
Molecular Mapping and Improvement of Leaf Rust Resistance in Wheat Breeding Lines
Authors: Tsilo Toi J. , Kolmer James A. , Anderson James A.
Published: February 2014

Leaf rust, caused by Puccinia triticina, is the most common and widespread disease of wheat (Triticum aestivum) worldwide. Deployment of host-plant resistance is one of the strategies to reduce losses due to leaf rust disease. The objective of this study was to map genes for adult-plant resistance to leaf rust in a recombinant inbred line (RIL) population originating from MN98550-5/MN99394-1. The mapping population of 139 RILs and five checks were evaluated in 2005, 2009, and 2010 in five environments. Natural infection occurred in the 2005 trials and trials in 2009 and 2010 were inoculated with leaf rust. Four quantitative trait loci (QTL) on chromosomes 2BS, 2DS, 7AL, and 7DS were detected. The QTL on 2BS explained up to 33.6% of the phenotypic variation in leaf rust response, whereas the QTL on 2DS, 7AL, and 7DS explained up to 15.7, 8.1, and 34.2%, respectively. Seedling infection type tests conducted with P. triticina races BBBD and SBDG confirmed that the QTL on 2BS and 2DS were Lr16 and Lr2a, respectively, and these genes were expressed in the seedling and field plot tests. The Lr2a gene mapped at the same location as Sr6. The QTL on 7DS was Lr34. The QTL on 7AL is a new QTL for leaf rust resistance. The joint effects of all four QTL explained 74% of the total phenotypic variation in leaf rust severity. Analysis of different combinations of QTL showed that the RILs containing all four or three of the QTL had the lowest average leaf rust severity in all five environments. Deployment of these QTL in combination or with other effective genes will lead to successful control of leaf rust.
Multidisciplinary Testing of Floor Pads on Stability, Energy Absorption, and Ease of Hospital Use for Enhanced Patient Safety
Authors: Crane Barbara , Goodworth Adam D. , Liquori Melissa , Ghosh Suhash , Certo Catherine , McCafferty Lorraine
Published: February 2014

Objectives

A major improvement in hospital safety could be realized if serious injury did not accompany falls. We studied several commercially available floor pads made of different materials to determine which (if any) would be practical in a hospital room and reduce injury without posing a threat to the balance of patients.

Methods

A multidisciplinary approach was undertaken to (1) measure upper and lower body motion in 17 young (<50 years) and 17 older (>55 years) adults during an instrumented sit to stand test from a hospital bed onto the different floor pads, (2) predict the energy dissipation available in floor pads by quantifying the relative mechanical properties, and (3) obtain professional feedback from hospital nurses via a questionnaire (8 questions) following a period of working on the different floor pads. Five floor pads, composed of foam, gel, and/or rubber were tested. All pads were compared with a typical hospital floor (concrete covered with linoleum tiles, considered the control).

Results

All of the pads subject to mechanical testing showed at least 3 times more energy absorption compared with the control. Balance testing showed that three of the pads resulted in minimal or no significant increases in body motion during sit-to-stand. Nursing feedback revealed that only 2 of these 3 pads may be feasible for hospital room use: one made primarily of firm rubber and one made of foam.

Conclusions

Floor pads do exist that show promise for hospital use that absorbing energy without major impacts on balance during sit-to-stand. Although only commercially available pads were investigated, results may inform the design and multidisciplinary testing of other floor surfaces.
Competition, virulence, host body mass and the diversification of macro-parasites
Authors: Rascalou Guilhem , Gourbière Sébastien
Published: February 2014

Adaptive speciation has been much debated in recent years, with a strong emphasis on how competition can lead to the diversification of ecological and sexual traits. Surprisingly, little attention has been paid to this evolutionary process to explain intrahost diversification of parasites. We expanded the theory of competitive speciation to look at the effect of key features of the parasite lifestyle, namely fragmentation, aggregation and virulence, on the conditions and rate of sympatric speciation under the standard ‘pleiotropic scenario’. The conditions for competitive speciation were found similar to those for non-parasite species, but not the rate of diversification. Adaptive evolution proceeds faster in highly fragmented parasite populations and for weakly aggregated and virulent parasites. Combining these theoretical results with standard empirical allometric relationships, we showed that parasite diversification can be faster in host species of intermediate body mass. The increase in parasite load with body mass, indeed, fuels evolution by increasing mutants production, but because of the deleterious effect of virulence, it simultaneously weakens selection for resource specialization. Those two antagonistic effects lead to optimal parasite burden and host body mass for diversification. Data on the diversity of fishes' gills parasites were found consistent with the existence of such optimum.
On the quasi-steady aerodynamics of normal hovering flight part I: the induced power factor
Authors: Nabawy Mostafa R. A. , Crowther William J.
Published: February 2014

An analytical treatment to quantify the losses captured in the induced power factor,k, is provided for flapping wings in normal hover, including the effects of non-uniform downwash, tip losses and finite flapping amplitude. The method is based on a novel combination of actuator disc and lifting line blade theories that also takes into account the effect of advance ratio. The model has been evaluated against experimental results from the literature and qualitative agreement obtained for the effect of advance ratio on the lift coefficient of revolving wings. Comparison with quantitative experimental data for the circulation as a function of span for a fruitfly wing shows that the model is able to correctly predict the circulation shape of variation, including both the magnitude of the peak circulation and the rate of decay in circulation towards zero. An evaluation of the contributions to induced power factor in normal hover for eight insects is provided. It is also shown how Reynolds number can be accounted for in the induced power factor, and good agreement is obtained between predicted span efficiency as a function of Reynolds number and numerical results from the literature. Lastly, it is shown that for a flapping wing in hoverkowing to the non-uniform downwash effect can be reduced to 1.02 using an arcsech chord distribution. For morphologically realistic wing shapes based on beta distributions, it is shown that a value of 1.07 can be achieved for a radius of first moment of wing area at 40% of wing length.
Space–time-bounded quantum fields for detection processes
Authors: Aguayo Fernando J. , Jaroszkiewicz George
Published: February 2014

We discuss a quantum field detection model comprising two types of detection procedures: maximal detection, where the initial state of the system and detectors undergoes an irreversible evolution, and minimal detection, where the system–detector interaction consists of a small, reversible coupling and posterior maximal detection performed over the detector system. Combined, these detection procedures allow for a time-dependent description of signalling experiments involving yes/no type of questions. A particular minimal detection model, stable in the presence of the vacuum, is presented and studied, successfully reproducing the localization of the state after a detection.
Zero and root loci of disturbed spring–mass systems
Authors: Lecomte Christophe
Published: February 2014

Models consisting of chains of particles that are coupled to their neighbours appear in many applications in physics or engineering, such as in the study of dynamics of mono-atomic and multi-atomic lattices, the resonances of crystals with impurities and the response of damaged bladed discs. Analytical properties of the dynamic responses of such disturbed chains of identical springs and masses are presented, including when damping is present. Several remarkable properties in the location of the resonances (poles) and anti-resonances (zeros) of the displacements in the frequency domain are presented and proved. In particular, it is shown that there exists an elliptical region in the frequency–disturbance magnitude plane from which zeros are excluded and the discrete values of the frequency and disturbance at which double poles occur are identified. A particular focus is on a local disturbance, such as when a spring or damper is modified at or between the first and last masses. It is demonstrated how, notably through normalization, the techniques and results of the paper apply to a broad category of more complex systems in physics, chemistry and engineering.
A quantum prisoner's dilemma cellular automaton
Authors: Alonso-Sanz Ramón
Published: February 2014

The dynamics of a spatial quantum formulation of the iterated prisoner's dilemma game is studied in this work. The game is played in the cellular automata manner, i.e. with local and synchronous interaction. The evolution is driven by the imitation of the best neighbour. It is shown how spatial structure enables in fully quantum contests a dramatically rapid emergence of mutual cooperation. In unfair contests, such as quantum versus classic players, the velocity in which the quantum players take advantage of its privileged status is also very notable.
Extracellular DNA can preserve the genetic signatures of present and past viral infection events in deep hypersaline anoxic basins
Authors: Corinaldesi C. , Tangherlini M. , Luna G. M. , Dell'Anno A.
Published: February 2014

Deep hypersaline anoxic basins (DHABs) of the Mediterranean Sea are among the most extreme ecosystems on Earth and host abundant, active and diversified prokaryotic assemblages. However, factors influencing biodiversity and ecosystem functioning are still largely unknown. We investigated, for the first time, the impact of viruses on the prokaryotic assemblages and dynamics of extracellular DNA pool in the sediments of La Medee, the largest DHAB found on Earth. We also compared, in La Medee and L'Atalante sediments, the diversity of prokaryotic 16S rDNA sequences contained in the extracellular DNA released by virus-induced prokaryotic mortality. We found that DHAB sediments are hot-spots of viral infections, which largely contribute to the release of high amounts of extracellular DNA. DNase activities in DHAB sediments were much higher than other extracellular enzymatic activities, suggesting that extracellular DNA released from killed prokaryotes can be the most suitable trophic resource for benthic prokaryotes. Preserved extracellular DNA pools, which contained novel and diversified gene sequences, were very similar between the DHABs but dissimilar from the respective microbial DNA pools. We conclude that the strong viral impact in DHAB sediments influences the genetic composition of extracellular DNA, which can preserve the signatures of present and past infections.
Decoupling of body-plan diversification and ecological structuring during the Ediacaran–Cambrian transition: evolutionary and geobiological feedbacks
Authors: Mángano M. Gabriela , Buatois Luis A.
Published: February 2014

The rapid appearance of bilaterian clades at the beginning of the Phanerozoic is one of the most intriguing topics in macroevolution. However, the complex feedbacks between diversification and ecological interactions are still poorly understood. Here, we show that a systematic and comprehensive analysis of the trace-fossil record of the Ediacaran–Cambrian transition indicates that body-plan diversification and ecological structuring were decoupled. The appearance of a wide repertoire of behavioural strategies and body plans occurred by the Fortunian. However, a major shift in benthic ecological structure, recording the establishment of a suspension-feeder infauna, increased complexity of the trophic web, and coupling of benthos and plankton took place during Cambrian Stage 2. Both phases were accompanied by different styles of ecosystem engineering, but only the second one resulted in the establishment of the Phanerozoic-style ecology. In turn, the suspension-feeding infauna may have been the ecological drivers of a further diversification of deposit-feeding strategies by Cambrian Stage 3, favouring an ecological spillover scenario. Trace-fossil information strongly supports the Cambrian explosion, but allows for a short time of phylogenetic fuse during the terminal Ediacaran–Fortunian.
Widespread and frequent horizontal transfers of transposable elements in plants
Authors: El Baidouri Moaine , Carpentier Marie-Christine , Cooke Richard , Gao Dongying , Lasserre Eric , Llauro Christel , Mirouze Marie , Picault Nathalie , Jackson Scott A. , Panaud Olivier
Published: February 2014

Vertical, transgenerational transmission of genetic material occurs through reproduction of living organisms. In addition to vertical inheritance, horizontal gene transfer between reproductively isolated species has recently been shown to be an important, if not dominant, mechanism in the evolution of prokaryotic genomes. In contrast, only a few horizontal transfer (HT) events have been characterized so far in eukaryotes and mainly concern transposable elements (TEs). Whether these are frequent and have a significant impact on genome evolution remains largely unknown. We performed a computational search for highly conserved LTR retrotransposons among 40 sequenced eukaryotic genomes representing the major plant families. We found that 26 genomes (65%) harbor at least one case of horizontal TE transfer (HTT). These transfers concern species as distantly related as palm and grapevine, tomato and bean, or poplar and peach. In total, we identified 32 cases of HTTs, which could translate into more than 2 million among the 13,551 monocot and dicot genera. Moreover, we show that these TEs have remained functional after their transfer, occasionally causing a transpositional burst. This suggests that plants can frequently exchange genetic material through horizontal transfers and that this mechanism may be important in TE-driven genome evolution.
A Subfamily of Putative Cytokinin Receptors Is Revealed by an Analysis of the Evolution of the Two-Component Signaling System of Plants
Authors: Gruhn Nijuscha , Halawa Mhyeddeen , Snel Berend , Seidl Michael F. , Heyl Alexander
Published: February 2014

The two-component signaling system—the major signaling pathway of bacteria—is found among higher eukaryotes only in plants, where it regulates diverse processes, such as the signaling of the phytohormone cytokinin. Cytokinin is perceived by a hybrid histidine (His) kinase receptor, and the signal is transduced by a multistep phosphorelay system of His phosphotransfer proteins and different classes of response regulators (RRs). To shed light on the origin and evolution of the two-component signaling system members in plants, we conducted a comprehensive domain-based phylogenetic study across the relevant kingdoms, including Charophyceae algae, the group of green algae giving rise to land plants. Surprisingly, we identified a subfamily of cytokinin receptors with members only from the early diverging land plants Marchantia polymorpha and Physcomitrella patens and then experimentally characterized two members of this subfamily. His phosphotransfer proteins of Charophyceae seemed to be more closely related to land plants than to other groups of green algae. Farther down the signaling pathway, the type-B RRs were found across all plant clades, but many members lack either the canonical Asp residue or the DNA binding domain. In contrast, the type-A RRs seemed to be limited to land plants. Finally, the analysis provided hints that one additional group of RRs, the type-C RRs, might be degenerated receptors and thus, of a different evolutionary origin than bona fide RRs.
Lifetime consequences of food protein‐carbohydrate content for an insect herbivore
Authors: Roeder Karl A. , Behmer Spencer T.
Published: February 2014

Food protein–carbohydrate content has significant consequences for animal survival, growth and reproduction. Rarely, though, is its effect examined over an animal's entire lifetime.

In this study, we reared newly hatched caterpillars [Heliothis virescens Fabricus (Lepidoptera: Noctuidae)] on diets containing different protein/carbohydrate (p/c) ratios. We recorded larval survival, time to pupation, pupal mass, eclosion success, time to eclosion and pupal body lipid content. Additionally, for each treatment, we mated eclosed males and females and measured egg production and egg viability.

Larval performance (survival to pupation and time to pupation) was similar across all except the two most extreme treatments. In contrast, pupal performance (mass, eclosion success and time to eclosion) was best on diets that were balanced or slightly protein‐biased. However, eclosion success differed between sexes. For males, it was best on diets with balanced p/c ratios, while female eclosion was strong across all but the most carbohydrate‐biased diet. Pupal body lipid content in both males and females increased as the food p/c ratio decreased.

Egg production was best on diets with balanced or slightly protein‐biased p/c ratios.

We also estimated the effect of food p/c ratio at the population level, using the data generated in this study. Population size was largest on diets with a balanced p/c ratio and declined steadily and strongly as the food p/c ratio became increasingly more imbalanced.

Our findings show, for the first time, the effect of food p/c content over an insect herbivore's entire life. Our data indicate that there is a narrow range of p/c ratios that maximize lifetime performance, and for H. virescens, this range coincides with its self‐selected p/c ratio.
Life‐history diversity and its importance to population stability and persistence of a migratory fish: steelhead in two large North American watersheds
Authors: Moore Jonathan W. , Yeakel Justin D. , Peard Dean , Lough Jeff , Beere Mark
Published: February 2014

Life‐history strategies can buffer individuals and populations from environmental variability. For instance, it is possible that asynchronous dynamics among different life histories can stabilize populations through portfolio effects.

Here, we examine life‐history diversity and its importance to stability for an iconic migratory fish species. In particular, we examined steelhead (Oncorhynchus mykiss), an anadromous and iteroparous salmonid, in two large, relatively pristine, watersheds, the Skeena and Nass, in north‐western British Columbia, Canada. We synthesized life‐history information derived from scales collected from adult steelhead (N = 7227) in these watersheds across a decade.

These migratory fishes expressed 36 different manifestations of the anadromous life‐history strategy, with 16 different combinations of freshwater and marine ages, 7·6% of fish performing multiple spawning migrations, and up to a maximum of four spawning migrations per lifetime. Furthermore, in the Nass watershed, various life histories were differently prevalent through time – three different life histories were the most prevalent in a given year, and no life history ever represented more than 45% of the population.

These asynchronous dynamics among life histories decreased the variability of numerical abundance and biomass of the aggregated population so that it was > 20% more stable than the stability of the weighted average of specific life histories: evidence of a substantial portfolio effect. Year of ocean entry was a key driver of dynamics; the median correlation coefficient of abundance of life histories that entered the ocean the same year was 2·5 times higher than the median pairwise coefficient of life histories that entered the ocean at different times. Simulations illustrated how different elements of life‐history diversity contribute to stability and persistence of populations.

This study provides evidence that life‐history diversity can dampen fluctuations in population abundances and biomass via portfolio effects. Conserving genetic integrity and habitat diversity in these and other large watersheds can enable a diversity of life histories that increases population and biomass stability in the face of environmental variability.
Dispersal‐mediated effect of microhabitat availability and density dependence determine population dynamics of a forest floor web spider
Authors: Takada Mayura B. , Miyashita Tadashi
Published: February 2014

Landscapes in nature can be viewed as a continuum of small total habitable area with high fragmentation to widely spreading habitats. The dispersal‐mediated rescue effect predominates in the former landscapes, while classical density‐dependent processes generally prevail in widely spread habitats. A similar principle should be applied to populations of organisms utilizing microhabitats in limited supply.

To test this hypothesis, we examined the population dynamics of a web spider,Neriene brongersmai,in 16 populations with varying degrees of microhabitat availability, and we explored whether: (i) high microhabitat availability improves survival rate during density‐independent movement, while the resultant high density reduces survival rate in a density‐dependent manner; and (ii) temporal population stability increases with microhabitat availability at the population level. Furthermore, we conducted two types of field experiments to verify whether high microhabitat availability actually reduces mortality associated with web‐site movement.

Field observations revealed that demographic change inN. brongersmaipopulations was affected by three factors at different stages, namely the microhabitat limitation from the early to late juvenile stages, the density dependence from the late juvenile to adult stages and the food limitation from the adult to the next early juvenile stages. In addition, there was a tendency for a positive association between population stability and microhabitat availability at the population level.

A small‐scale experiment, where the frequency of spider web relocation was equalized artificially, revealed that high microhabitat availability elevated the survival rate during a movement event between web‐sites. The larger spatiotemporal scale experiment also revealed an improved spider survival rate following treatment with high microhabitat availability, even though spider density was kept at a relatively low level.

The population dynamics ofN. brongersmaican be determined primarily by density‐independent processes based on web‐site fragmentation and density‐dependent processes driven by interference competition. We conclude that depending on the amount of habitat resources, the relative importance of the two contrasting paradigms—equilibrium and non‐equilibrium—appears to vary, even within a particular system.