bluuebunny/crossref_metadata_2025 huggingface dataset:
Robotic‐assisted Colorectal Surgery in the United States: A Nationwide Analysis of Trends and Outcomes
Authors: Halabi Wissam J. , Kang Celeste Y. , Jafari Mehraneh D. , Nguyen Vinh Q. , Carmichael Joseph C. , Mills Steven , Stamos Michael J. , Pigazzi Alessio
Published: April 2013

Background

While robotic‐assisted colorectal surgery (RACS) is becoming increasingly popular, data comparing its outcomes to other established techniques remain limited to small case series. Moreover, there are no large studies evaluating the trends of RACS at the national level.

Methods

The Nationwide Inpatient Sample 2009–2010 was retrospectively reviewed for robotic‐assisted and laparoscopic colorectal procedures performed for cancer, benign polyps, and diverticular disease. Trends in different settings, indications, and demographics were analyzed. Multivariate regression analysis was used to compare selected outcomes between RACS and conventional laparoscopic surgery (CLS).

Results

An estimated 128,288 colorectal procedures were performed through minimally invasive techniques over the study period, and RACS was used in 2.78 % of cases. From 2009 to 2010, the use of robotics increased in all hospital settings but was still more common in large, urban, and teaching hospitals. Rectal cancer was the most common indication for RACS, with a tendency toward its selective use in male patients. On multivariate analysis, robotic surgery was associated with higher hospital charges in colonic ($11,601.39; 95 % CI 6,921.82–16,280.97) and rectal cases ($12,964.90; 95 % CI 6,534.79–19,395.01), and higher rates of postoperative bleeding in colonic cases (OR = 2.15; 95 % CI 1.27– 3.65). RACS was similar to CLS with respect to length of hospital stay, morbidity, anastomotic leak, and ileus. Conversion to open surgery was significantly lower in robotic colonic and rectal procedures (0.41; 95 % CI 0.25–0.67) and (0.10; 95 % CI 0.06–0.16), respectively.

Conclusions

The use of RACS is still limited in the United States. However, its use increased over the study period despite higher associated charges and no real advantages over laparoscopy in terms of outcome. The one advantage is lower conversion rates.
Smoking cessation counselling practices of family physicians in Jordan
Authors: Alomari Mousa Abdullah , Khader Yousef Saleh , Dauod Ali Shakir , Abu-Hammour Khaled Adel , Khassawneh Adi Harbi , Jibril Nuha Ibrahim
Published: April 2013

Objectives: To assess the smoking cessation counselling practices of family physicians in Jordan and assess their perception about the availability of smoking cessation resources and about the barriers to effective smoking cessation practices. Methods: A pre-structured questionnaire was distributed to 124 family physicians practicing in teaching and Ministry of Health medical centres in Jordan. All participants were asked about their smoking cessation practices and about the barriers to effective smoking cessation practices. Results: Only 39.8% reported that they assess the willingness of the patients to quit smoking and 28.2% reported that they discuss counselling options with smokers. Considerably fewer percentages of physicians reported that they prepare their patients for withdrawal symptoms (11.6%), discuss pharmacotherapies (4.9%), describe a nicotine patch (5.0%), and provide patients with self-help materials (6.7%). The two factors cited most often by physicians as significant barriers to smoking cessation counselling were lack or too few available cessation programmes (90.3%) and limited training for physicians on tobacco and cessation interventions (90.3%). Conclusion: While a high proportion of Jordanian family physicians reported that they usually ask patients about smoking status and advise them to stop smoking, they do not regularly provide extensive assistance to help their patients to quit smoking. Lack or too few available cessation programmes and limited training for physicians on smoking cessation interventions were identified as the two major barriers to effective smoking cessation counselling.
Radiocarbon dating of musk-ox (Ovibos moschatus) bones from the Thule region, northwest Greenland
Authors: Bennike Ole
Published: April 2013

The Thule region in north Greenland formerly supported a population of musk-oxen (Ovibos moschatus). Radiocarbon dating of bones of this mammal collected on the terrain surface and from archaeological sites has yielded late Holocene ages, indicating that the species was a late immigrant to this part of Greenland. The species may have arrived at a time when the area was uninhabited, and it had at least a thousand years to spread south, before the Late Dorset people arrived. The heavy glaciation of Melville Bugt in the late Holocene was probably the main reason that the musk-ox did not disperse south to west Greenland. The population of musk-ox in the region may have peaked during the Medieval Warm Period, and the species survived during the occupation of the region by the Late Dorset people. The size of the population may have declined during the beginning of the Little Ice Age, and musk-ox was probably exterminated from the region shortly after the arrival of the mobile Thule people.
Leisure, economy and colonial urbanism: Darjeeling, 1835–1930
Authors: BHATTACHARYA NANDINI
Published: April 2013

This article posits that the hill station of Darjeeling was a unique form of colonial urbanism. It shifts historiographical interest from major urban centres in colonial India (such as Bombay or Calcutta) and instead attempts a greater understanding of smaller urban centres. In the process, it also interrogates the category of hill stations, which have been understood as exotic and scenic sites rather than as towns that were integral to the colonial economy. In arguing that hill stations, particularly Darjeeling, were not merely the scenic and healthy ‘other’ of the clamorous, dirty and diseased plains of India, it refutes suggestions that the ‘despoiling’ or overcrowding of Darjeeling was incremental to the purposes of its establishment. Instead, it suggests that Darjeeling was part of the colonial mainstream; its urbanization and inclusion into the greater colonial economy was effected from the time of its establishment. Therefore, a constant tension between its exotic and its functional elements persisted throughout.
Zusammenhang zwischen Empathie und dem Verstehen literarischer Texte
Authors: Henschel Sofie , Roick Thorsten
Published: April 2013

Affektive Komponenten, wie die Empathie, werden in der Literaturwissenschaft als bedeutsam für das Verstehen literarischer Texte erachtet. Empirische Belege gibt es dafür bislang aber nicht. Die vorliegende Studie untersucht den Zusammenhang zwischen Empathie und dem Verstehen literarischer Texte resp. Sachtexte unter Berücksichtigung motivationaler und soziodemografischer Hintergrundmerkmale. An der Untersuchung nahmen 1369 Jugendliche der 9. Klassenstufe teil. Die Jugendlichen bearbeiteten Testverfahren zum Verstehen literarischer Texte und Sachtexte und einen Fragebogen, über den soziodemografische und motivationale Variablen sowie Teilfacetten der Empathie erfasst wurden. Während Betroffenheit und kognitive Fantasieempathie keine bedeutsamen Zusammenhänge mit dem Textverstehen aufweisen, zeigt sich, dass emotionale Fantasieempathie stärker mit dem literarischen Textverstehen zusammenhängt als mit dem Sachtextverstehen. Dieser differenzielle Zusammenhang bleibt auch unter Kontrolle soziodemografischer und motivationaler Merkmale erhalten.
Retracted Article: Doping, strain, defects and magneto-optical properties of Zn1−xMnxO nanocrystals
Authors: Sharma Prashant K. , Dutta Ranu K. , Choudhary R. J. , Pandey Avinash C.
Published: April 2013

High resolution transmission electron microscopic images of ZnO:Mn2+ nanoparticles, for (a) 10% Mn doping, showing defect free regular atomic arrangement, and (b) 20% Mn doping, irregular lattice planes with significant defects. (c) Digital photograph of liquid suspension of ZnO:Mn2+ nanocrystals under UV lamp. (d) MH loop of ZnO:Mn2+ nanoparticles.
Accurate combined-hyperbolic-inverse-power-representation of ab initio potential energy surface for the hydroperoxyl radical and dynamics study of $\bf O+OH$O+OH reaction
Authors: Varandas A. J. C.
Published: April 2013

The Combined-Hyperbolic-Inverse-Power-Representation method, which treats evenly both short- and long-range interactions, is used to fit an extensive set of ab initio points for HO2 previously utilized [Xu et al., J. Chem. Phys. 122, 244305 (2005)10.1063/1.1944290] to develop a spline interpolant. The novel form is shown to perform accurately when compared with others, while quasiclassical trajectory calculations of the O + OH reaction clearly pinpoint the role of long-range forces at low temperatures.
Measurement of specific contact resistivity using scanning voltage probes
Authors: Wang Weigang , Beasley Malcolm R.
Published: April 2013

Specific contact resistivity measurements have conventionally been heavy in both fabrication and simulation/calculation in order to account for complicated geometries and other effects such as parasitic resistance. We propose a simpler geometry to deliver current and the use of a scanning voltage probe to sense the potential variation along the sample surface, from which the specific contact resistivity can be straightforwardly deduced. We demonstrate an analytical example in the case where both materials are thin films. Experimental data with a scanning Kelvin probe measurement on graphene from the literature corroborate our model calculation.
The magnetic, relaxometric, and optical properties of gadolinium-catalyzed single walled carbon nanotubes
Authors: Sitharaman Balaji , Jacobson Barry D. , Wadghiri Youssef Z. , Bryant Henry , Frank Joseph
Published: April 2013

We report the magnetic behavior, relaxometry, phantom magnetic resonance imaging (MRI), and near-infrared (NIR) photoluminescence spectroscopy of gadolinium (Gd) catalyzed single-walled carbon nanotubes (Gd-SWCNTs). Gd-SWCNTs are paramagnetic with an effective magnetic moment of 7.29 μB. Gd-SWCNT solutions show high r1 and r2 relaxivities at very low (0.01 MHz) to clinically relevant (61 MHz) magnetic fields (r1 ≥ 130 mM−1 s−1, r2 ≥ 160 mM−1 s−1). Analysis of nuclear magnetic resonance dispersion profiles using Solomon, Bloembergen, and Morgan equations suggests that multiple structural and dynamic parameters such as rotational correlation time τR, rate of water exchange τM, and the number of fast-exchanging water molecules within the inner sphere q may be responsible for the increase in r1 and r2 relaxivity. The T1 weighted MRI signal intensity (gradient echo sequence; repetition time (TR) = 66 ms, echo time (TE) = 3 ms, flop angle = 108°) of Gd-SWCNT phantom solution is 14 times greater than the Gd-based clinical MRI contrast agent Magnevist. Additionally, these nanotubes exhibit near infrared fluorescence with distinct E11 transitions of several semiconducting SWCNTs. Taken together, these results demonstrate that Gd-SWCNTs have potential as a novel, highly efficacious, multimodal MRI-NIR optical imaging contrast agent.
Cumulative energy, emissions, and water consumption for geothermal electric power production
Authors: Sullivan J. L. , Clark C. , Han J. , Harto C. , Wang M.
Published: April 2013

A life cycle analysis has been conducted on geothermal electricity generation. The technologies covered in the study include flash, binary, enhanced geothermal systems (EGS), and coproduced gas and electricity plants. The life cycle performance metrics quantified in the study include materials, water, and energy use, and greenhouse gas (GHG) emissions. The life cycle stages taken into account were the plant and fuel cycle stages, the latter of which includes fuel production and fuel use (operational). The plant cycle includes the construction of the plant, wells, and above ground piping and the production of the materials that comprise those systems. With the exception of geothermal flash plants, GHG emissions from the plant cycle are generally small and the only such emissions from geothermal plants. Some operational GHGs arise from flash plants, and though substantial when compared to other geothermal power plants, these are nonetheless considerably smaller than those emitted from fossil fuel fired plants. For operational geothermal emissions, an emission rate (g/kW h) distribution function vs. cumulative capacity was developed using California plant data. Substantial GHG emissions arise from coproduced facilities and two other “renewable” power plants, but these are almost totally due to the production and use of natural gas and biofuels. Nonetheless, those GHGs are still much less than those from fossil fuel fired plants. Though significant amounts of water are consumed for plant and well construction, especially for well field stimulation of EGS plants, they are small in comparison to estimated water consumed during plant operation. This also applies to air cooled plants, which nominally should consume no water during operation. Considering that geothermal operational water use data are scarce, our estimates show the lowest water consumption for flash and coproduced plants and the highest for EGS, though the latter must be considered provisional due to the absence of field data. The EGS estimate was based on binary plant data.
An analysis of the explosion limits of hydrogen-oxygen mixtures
Authors: Wang Xianming , Law Chung K.
Published: April 2013

In this study, the essential factors governing the Z-shaped explosion limits of hydrogen-oxygen mixtures are studied using eigenvalue analysis. In particular, it is demonstrated that the wall destruction of H and HO2 is essential for the occurrence of the first and third limits, while that of O, OH, and H2O2 play secondary, quantitative roles for such limits. By performing quasi-steady-state analysis, an approximate, cubic equation for the explosion limits is obtained, from which explicit expressions governing the various explosion limits including the state of the loss of non-monotonicity are derived and discussed.
Novel in situ device for investigating the tensile and fatigue behaviors of bulk materials
Authors: Ma Zhichao , Zhao Hongwei , Li Qinchao , Wang Kaiting , Zhou Xiaoqin , Hu Xiaoli , Cheng Hongbing , Lu Shuai
Published: April 2013

For investigating the static tensile and dynamic fatigue behaviors of bulk materials, a miniaturized device with separate modular tensile and fatigue actuators was developed. The fatigue actuator presented good compatibility with the tensile actuator and mainly consisted of a special flexure hinge and piezoelectric stack. In situ fatigue tests under scanning electron microscope or metallographic microscope could be carried out due to the miniaturized dimensions of the device. A displacement correction method of tensile actuator based on load sensor compliance was investigated, and the feasibility of the method was verified by the comparison tests with a commercial tensile instrument. The application of testing the storage and loss modulus as a function of frequency was explained, and the temperature rises of both the piezoelectric stack and specimen were obtained as a function of frequency. Output characteristics of the fatigue actuator were also investigated. Additionally, the discharge performance of piezoelectric stack based on various initial voltages and fatigue tests on C11000 copper was carried out. This paper shows a modularized example that combines a servo motor with a piezoelectric actuator attached to the specimen grip to realize the in situ fatigue tests.
Critical magnetic behavior of magnetocaloric materials with the Gd5Si4-type structure
Authors: Belo J. H. , Pereira A. M. , Magen C. , Morellon L. , Ibarra M. R. , Algarabel P. A. , Araújo J. P.
Published: April 2013

An extensive investigation on the magnetism of Gd5(SixGe1−x)4 compounds which stabilize in the Gd5Si4-type structure is here presented, focusing on the Gd5Si4 and Gd5Si2Ge2 compositions. Through Arrott plot analysis, the temperature dependencies of the spontaneous magnetizations are retrieved and the magnetic interaction coefficients (Jexch) are estimated. The obtained Jexch value for Gd5Si4 is 15% higher than that of Gd5Si2Ge2. Such enhancement cannot be attributed to a magneto-volume coupling only, being mainly associated with the magnetic polarization of the (Si,Ge)-(Si,Ge) interslab connections. The critical exponents were estimated (δ=3.1 and 2.9, γ=1.01 and 1.06, β=0.48 and 0.56, and n=0.67 and 0.63 for Gd5Si4 and Gd5Si2Ge2, respectively) demonstrating that both compositions belong to the same universal class. This conclusion is reinforced by the construction of a universal logarithmic scaling plot of the M(H) isothermal curves. Hence, we conclude that the magnetism of the Gd5Si4-type structure compounds is simply dominated by long range ferromagnetic interactions. This contrasts to other Gd5(SixGe1−x)4 compositions where a strong competition antiferro versus ferromagnetic interactions and short versus long range order are observed. Finally, the Gd5Si4 composition has shown a reduction of 50% on the magnetic entropy change maxima when compared with the Gd5Si2Ge2 compound studied, despite its higher magnetic interaction coefficient value.
Bond breaking in a Morse chain under tension: Fragmentation patterns, higher index saddles, and bond healing
Authors: Mauguière F. A. L. , Collins P. , Ezra G. S. , Wiggins S.
Published: April 2013

We investigate the fragmentation dynamics of an atomic chain under tensile stress. We have classified the location, stability type (indices), and energy of all equilibria for the general n-particle chain, and have highlighted the importance of saddle points with index >1. We show that for an n = 2-particle chain under tensile stress the index 2 saddle plays a central role in organizing the dynamics. We apply normal form theory to analyze phase space structure and dynamics in a neighborhood of the index 2 saddle. We define a phase dividing surface (DS) that enables us to classify trajectories passing through a neighborhood of the saddle point using the values of the integrals associated with the normal form. We also generalize our definition of the dividing surface and define an extended dividing surface (EDS), which is used to sample and classify all trajectories that pass through a phase space neighborhood of the index 2 saddle at total energies less than that of the saddle. Classical trajectory simulations are used to study fragmentation patterns for the n = 2 chain under tension. That is, we investigate the relative probability for breaking one bond versus concerted fission of several (two, in this case) bonds. Initial conditions for trajectories are obtained by sampling the EDS at constant energy. We sample trajectories at fixed energies both above and below the energy of the saddle. The fate of trajectories (single versus multiple bond breakage) is explored as a function of the location of the initial condition on the EDS, and a connection made to the work of Chesnavich on collision-induced dissociation. A significant finding is that we can readily identify trajectories that exhibit bond healing. Such trajectories pass outside the nominal (index 1) transition state for single bond dissociation, but return to the potential well region, possibly several times, before ultimately dissociating.
Automated high precision secondary pH measurements
Authors: Bastkowski F. , Jakobsen P. T. , Stefan F. , Kristensen H. B. , Jensen H. D. , Kawiecki R. , Wied C. E. , Kauert A. , Seidl B. , Spitzer P. , Eberhardt R. , Adel B.
Published: April 2013

A new setup for high precision, automated secondary pH measurements together with a reference measurement procedure has been developed and tested in interlaboratory comparisons using buffers pH 4.005, pH 7.000, and pH 10.012 at 25 °C and 37 °C. Using primary buffers as standards, a standard uncertainty in pH better than 0.005 can be reached. The central measuring device is a one piece, thermostatted cell of PFA (perfluoroalkoxy) with a built-in Hamilton® Single Pore™ Glass electrode. Due to its flow-through principle this device allows pH measurements with low consumption of measurement solutions. The very hydrophobic and smooth PFA as construction material facilitates complete emptying of the cell. Furthermore, the tempering unit affords very precise temperature control and hence contributes to the low target uncertainty of the produced secondary buffer solutions. Use of a symmetric measurement sequence and the two point calibration was sufficient to reach high precision and accuracy.
Effective electrostatic interactions arising in core-shell charged microgel suspensions with added salt
Authors: Moncho-Jordá A. , Anta J. A. , Callejas-Fernández J.
Published: April 2013

The mixture formed by charged (ionic) microgels in the presence of 1:1 added salt, with explicit consideration of a core-shell structure of the microgel particles, is studied. By solving numerically the three-component Ornstein-Zernike integral equations, the counter- and coion penetration inside the microgel network and the resulting effective microgel-microgel electrostatic interaction are calculated. This is done in the limit of very low microgel concentration, so that the resulting pair-wise effective potential is not affected by many-body particle-particle interactions. The ion-ion, microgel-ion, and microgel-microgel correlations are all treated within the Hypernetted-Chain approximation. The results obtained clearly show that the addition of salt to the microgel suspension has a deep impact on the screening of the bare charge of the particles, confirming an already well-known result: the strong reduction of the effective charge of the microgel occurring even for diluted electrolyte concentrations. We show that this effect becomes more important as we increase the shell size of the particle and derive a semi-empirical model for the effective charge as a function of the electrolyte concentration and the shell extension. The resulting microgel-microgel effective pair potential is analysed as a function of the shell extension and salt concentration. In all cases the interaction is a soft potential when particles overlap. For non-overlapping distances, our theoretical results indicate that microgel particles can be regarded as hard spherical colloids bearing an effective charge given by the net charge inside the particle and the microgel-microgel interaction shows a Yukawa-like behaviour as a function of the interparticle distance. It is also observed that increasing the bare-charge of the microgel induces a strong microgel-counterion coupling in the limit of very low electrolyte concentrations, which cannot be justified using linearized theories. This leads to an even more important adsorption of counterions inside the microgel network and to a reduction of the microgel-microgel effective repulsion.
Magnetic anisotropy in Fe films epitaxied by thermal deposition and pulse laser deposition on GaAs(001)
Authors: Xiao X. , Liang J. H. , Huo Y. , Zhu J. , Chen G. , Wu Y. Z.
Published: April 2013

The in-plane magnetic anisotropy of Fe films fabricated with thermal deposition (TD) and pulse laser deposition (PLD) techniques on GaAs(001) substrate was studied quantitatively. The volume anisotropy in TD Fe film is attributed to the constant strain anisotropy, supported by reflection high-energy electron diffraction analysis. The PLD growth was found to deeply influence the interface anisotropy at Fe/GaAs interface even through a 30 ML Fe TD underlayer. The volume anisotropy was found to exist in TD Fe film even grown on top of a PLD film. Our study indicates that the uniaxial magnetic anisotropy in Fe/GaAs(001) system can be controlled by a combination of TD and PLD growth.
Electrostatic frequency shifts in amide I vibrational spectra: Direct parameterization against experiment
Authors: Reppert Mike , Tokmakoff Andrei
Published: April 2013

The interpretation of protein amide I infrared spectra has been greatly assisted by the observation that the vibrational frequency of a peptide unit reports on its local electrostatic environment. However, the interpretation of spectra remains largely qualitative due to a lack of direct quantitative connections between computational models and experimental data. Here, we present an empirical parameterization of an electrostatic amide I frequency map derived from the infrared absorption spectra of 28 dipeptides. The observed frequency shifts are analyzed in terms of the local electrostatic potential, field, and field gradient, evaluated at sites near the amide bond in molecular dynamics simulations. We find that the frequency shifts observed in experiment correlate very well with the electric field in the direction of the C=O bond evaluated at the position of the amide oxygen atom. A linear best-fit mapping between observed frequencies and electric field yield sample standard deviations of 2.8 and 3.7 cm−1 for the CHARMM27 and OPLS-AA force fields, respectively, and maximum deviations (within our data set) of 9 cm−1. These results are discussed in the broader context of amide I vibrational models and the effort to produce quantitative agreement between simulated and experimental absorption spectra.
Ultrafast dynamics of hot electrons and phonons in chemical vapor deposited graphene
Authors: Lin Kuan-Chun , Li Ming-Yang , Li L. J. , Ling D. C. , Chi C. C. , Chen Jeng-Chung
Published: April 2013

The relaxation dynamics of photoexcited carriers in a chemical vapor deposited graphene transferred on quartz substrate has been investigated by using ultrafast optical-pump terahertz (THz)-probe spectroscopy. Terahertz transmission through graphene sample is reduced by optical pumping. The change of transmission decays exponentially after the optical pulse. We find the relaxation time is insensitive to the substrate temperature from 10 K to 300 K but increases sublinearly with pump fluence. We model the relaxation process involving electron-phonon coupling together with a set of rate equations to describe the transient responses of quasi-particles and optical phonons. The increases of the extracted carrier temperature and the measured relaxation time with pump fluence are associated with the fact that high pump fluence significantly increases the carrier temperature and broadens the carrier distribution. As a result, it leads to the reduction of optical phonon emission efficiency and the decrease of cooling rate as well.
Electrical and chemical characteristics of Al2O3/InP metal-oxide-semiconductor capacitors
Authors: Galatage R. V. , Dong H. , Zhernokletov D. M. , Brennan B. , Hinkle C. L. , Wallace R. M. , Vogel E. M.
Published: April 2013

The interface trap density (Dit) and bonding at the Al2O3/InP interface was investigated using capacitance-voltage (C-V) measurements and X-ray photoelectron spectroscopy (XPS). The Dit extracted using C-V measurements show a peak near midgap and a tail, which extends into the InP conduction band. After post high-k deposition annealing, only midgap Dit increases while minimal change in conduction band Dit is observed. The magnitude of extracted Dit is higher for the Al2O3/InP interface compared to the HfO2/InP interface. XPS analysis shows that the native oxides at the Al2O3/InP interface are more phosphorous rich than for HfO2/InP interface.
Efficient inverted polymer solar cells with thermal-evaporated and solution-processed small molecular electron extraction layer
Authors: Sun Fu-Zhou , Shi Ai-Li , Xu Zai-Quan , Wei Huai-Xin , Li Yan-Qing , Lee Shuit-Tong , Tang Jian-Xin
Published: April 2013

Efficient inverted polymer solar cell is reported upon by integrating with a small molecular 1,3,5-tri(phenyl-2-benzimi-dazolyl)-benzene (TPBi) electron extraction layer (EEL) at low processing temperature with thermal-evaporation and solution-process, resulting in the power conversion efficiencies of 3.70% and 3.47%, respectively. The potential of TPBi as an efficient EEL is associated with its suitable electronic energy level for electron extraction and hole blocking from the active layer to the indium tin oxide cathode.
Mechanisms of ring and island formation in lattice mismatched droplet epitaxy
Authors: DeJarld M. , Reyes Kris , Smereka P. , Millunchick J. M.
Published: April 2013

Lattice mismatched GaSb nanostructures were grown using droplet epitaxy. In this method, liquid Ga droplets are deposited on GaAs substrates and then exposed to a Sb flux at various temperatures. At increasing temperature and droplet volumes, the morphologies changed from two-dimensional islands to nanoholes, three-dimensional islands, rings, and clusters of islands. A theoretical model describes the relationship between the volume of the droplet and the final nanostructure, and is validated by kinetic Monte Carlo simulations. The combined experimental and simulation results demonstrate another process to obtain complex nanostructures, widening the design window for devices.
Assessment of the thermal expansion mismatch in lanthanum strontium cobalt ferrite-yttria stabilized zirconia two-layers systems using photoacoustic methodology
Authors: Guimarães A. O. , Mansanares A. M. , Guimarães V. F. , Paes H. R. , Vargas H.
Published: April 2013

In this letter we investigate the thermo-elastic mismatch in lanthanum strontium cobalt ferrite (La0.6Sr0.4Co0.2Fe0.8O3−δ) (LSCF) films deposited onto yttria stabilized zirconia (YSZ) substrates, applicable to solid oxide fuel cells. We investigated composite LSCF+YSZ and pure LSCF films deposited onto commercial YSZ substrate. Photoacoustics was used to obtain the effective thermal diffusivity and thermal expansion coefficient of the two-layers samples. Based on a thermal–electrical analogy model, it was possible to get the thermo-elastic properties of the films and to confirm the desired reduction on the thermo-elastic mismatch between film and substrate when comparing composite LSCF+YSZ and pure LSCF films.
Assessment the effect of wheat farm sizes on energy consumption and CO2 emission
Authors: Sefeedpari P. , Ghahderijani M. , Pishgar-Komleh S. H.
Published: April 2013

High population growth and providing the food for this population have increased the amount of energy consumption in agricultural production systems. One of the most important issues for high energy consumption in recent century is the global warming where greenhouse gas (GHG) emission plays an important role. This study evaluated the energy balance between the input and output and the amount of GHG emission per unit area of wheat production in Iran. The total energy input and output were calculated as 31.5 and 44.6 GJ ha−1, respectively, where the highest energy consumer was chemical fertilizer with share of 64% of total energy. Total GHG emission was 1118.94 kgCO2eq ha−1 in which chemical fertilizer and diesel fuel had the highest contributions. The results of regression analysis indicated that use of 10 MJ in forms of direct, indirect, renewable, and nonrenewable energy leads to 3.0, 0.4, 2.8, and 0.6 kg ha−1 growth in wheat yield, respectively. The results of farm size analysis indicated that very large farms have better energy ratio and less GHG emission in comparison with other farm size levels due to better management. The results of this study indicated a list of choices which are available to reduce energy use and GHG emission in wheat production.
Electron transport through Ni/1,4-benzenedithiol/Ni single-molecule junctions under magnetic field
Authors: Horiguchi Kazunori , Sagisaka Takami , Kurokawa Shu , Sakai Akira
Published: April 2013

We have studied electron transport through Ni/1,4-benzenedithiol (BDT)/Ni single molecule junctions at cryogenic temperatures under magnetic field up to 250 mT. Instead of examining magnetoresistance (MR) of individual junctions, we measured the conductance of many junctions under a constant magnetic field and investigated how a single-molecule peak in a conductance histogram shifts with the field strength. We found that the single-molecule resistance at 77 K, deduced from the conductance peak position, shows a hysteresis against the field strength and takes a maximum around 50 mT when the magnetic field increases from 0 T to 150 mT. The observed resistance change yields a MR of ∼(80−90)% for Ni/BDT/Ni single molecule junctions. This MR is higher than experimental MR reported for non-conjugating molecules but consistent with high theoretical MR predicted for π-conjugated molecules such as BDT. We have also investigated the nonlinearity of the current-voltage (I−V) characteristics of Ni/BDT/Ni junctions under 0 T and 150 mT and found that the nonlinearity changes its sign from negative at 0 T to positive at 150 mT. This result suggests that the junction transmission spectrum at 0 T should have a low-lying peak within ±0.1 eV from the Fermi level, but the peak moves out of the bias window when the magnetic field increases to 150 mT. The observed field-induced change in the I−V nonlinearity is qualitatively consistent with theoretical I−V curves of Ni/BDT/Ni calculated for magnetized and non-magnetized Ni electrodes.
Polarization-resolved extinction and scattering cross-sections of individual gold nanoparticles measured by wide-field microscopy on a large ensemble
Authors: Payne Lukas M. , Langbein Wolfgang , Borri Paola
Published: April 2013

We report a simple, rapid, and quantitative wide-field technique to measure the optical extinction σext and scattering σsca cross-section of single nanoparticles using wide-field microscopy enabling simultaneous acquisition of hundreds of nanoparticles for statistical analysis. As a proof-of-principle, we measured gold nanoparticles of 40 nm and 100 nm diameter and found mean values and standard deviations of σext and σsca consistent with the literature. Switching from unpolarized to linearly polarized excitation, we measured σext as a function of the polarization direction and characterized the nanoparticle asphericity. The method can be implemented cost-effectively on any conventional wide-field microscope and is applicable to any nanoparticles.
Observation of double percolation transitions in Ag-SnO2 nanogranular films
Authors: Wei Yan-Fang , Li Zhi-Qing
Published: April 2013

Two percolation transitions are observed in Agx(SnO2)1−x nanogranular films with Ag volume fraction x ranging from ∼0.2 to ∼0.9. In the vicinity of each percolation threshold xci (i=1,2), the variation in σ with x obeys a power law for x>xci. The origin of the first percolation transition at xc1 (xc1>xc2) is similar to that of the classical one, while the second transition is explained as originating from the tunneling to the second-nearest neighboring Ag particles. These observations provide strong experimental support for the validity of current theories concerning tunneling effect in conductor-insulator nanogranular composites.
Bulk silicon as photonic dynamic infrared scene projector
Authors: Malyutenko V. K. , Bogatyrenko V. V. , Malyutenko O. Yu.
Published: April 2013

A Si-based fast (frame rate >1 kHz), large-scale (scene area 100 cm2), broadband (3–12 μm), dynamic contactless infrared (IR) scene projector is demonstrated. An IR movie appears on a scene because of the conversion of a visible scenario projected at a scene kept at elevated temperature. Light down conversion comes as a result of free carrier generation in a bulk Si scene followed by modulation of its thermal emission output in the spectral band of free carrier absorption. The experimental setup, an IR movie, figures of merit, and the process's advantages in comparison to other projector technologies are discussed.
Quasi-two-dimensional conducting layer on TiO2 (110) introduced by sputtering as a template for resistive switching
Authors: Rogala M. , Klusek Z. , Rodenbücher C. , Waser R. , Szot K.
Published: April 2013

The insulator-to-metal transformation in the surface layer of TiO2 (110) induced by the Ar+ ion sputtering process is analyzed on the nanoscale. Local conductivity atomic force microscopy and photoelectron spectroscopy allow the changes in the valence of the Ti ions in the surface layer to be linked to the formation of its grain-like structure. The investigation of the cleavage plane of the crystal allowed us to estimate the thickness of the quasi-two-dimensional conducting layer generated by ion bombardment as 30 nm. The conducting layer is a template where the resistive switching of each single grain can be carried out.
X-ray diffraction study of surface acoustic waves and pseudo-surface acoustic waves propagation in La3Ga5.5Ta0.5O14 crystal
Authors: Roshchupkin Dmitry , Ortega Luc , Plotitcyna Olga , Erko Alexei , Zizak Ivo , Irzhak Dmitry
Published: April 2013

X-ray diffraction on the crystal La3Ga5.5Ta0.5O14 modulated by surface acoustic waves (SAW) and pseudo-surface acoustic waves (PSAW) with wavelength of Λ=8 μm was studied using a double axis X-ray diffractometer at the BESSY II synchrotron radiation source. The propagation of SAW and PSAW leads to sinusoidal modulation of the crystal lattice and gives rise to diffraction satellites on the rocking curve, with the intensity and angular divergence between the diffraction satellites depending on the wavelength and amplitude of the crystal lattice acoustic modulation. The analysis of diffraction spectra enables the determination of the amplitude and acoustic wavelengths, and power flow angles of acoustic energy propagation. The investigation of acoustic wave fields showed that PSAW is a flowing back wave which propagates at an angle to the crystal surface.
Atomically smooth and homogeneously N-polar AlN film grown on silicon by alumination of Si3N4
Authors: Hu Jiannan , Hao Zhibiao , Niu Lang , E Yanxiong , Wang Lai , Luo Yi
Published: April 2013

By using an alumination process of Si3N4 at high temperature with aluminum flux irradiation for sufficient time, homogeneously N-polar and atomically smooth AlN film has been realized on silicon substrate with inversion domain suppressed to less than 3.0 × 106 cm−2 and root mean square surface roughness of ∼0.4 nm. A general interface model is proposed to explain the mechanism of polarity determination. The sharp AlN(0001)/Si(111) interface exhibits 5:4 coincidence domain matching, resulting in an almost fully relaxed AlN film.
Terahertz intersubband electroluminescence from InAs quantum cascade light emitting structures
Authors: Ohtani K. , Fischer M. , Scalari G. , Beck M. , Faist J.
Published: April 2013

Terahertz intersubband electroluminescence from an InAs/AlSb quantum cascade structure based on a single quantum well active layer is studied. A sharp electroluminescence peak with a linewidth of 0.6 meV is observed at 4 THz. Low temperature magneto-transport measurements are also performed to investigate alignment of subbands in the active layer. The model taking account of a conduction band nonparabolicity reproduces well the subband energy in the InAs/AlSb THz quantum cascade structure.
Generation of second harmonic radiation from sub-stoichiometric silicon nitride thin films
Authors: Francesco Pecora Emanuele , Capretti Antonio , Miano Giovanni , Dal Negro Luca
Published: April 2013

Enhancing second-order optical processes in Si-compatible materials is important for the demonstration of innovative functionalities and nonlinear optical devices integrated on a chip. Here, we demonstrate significantly enhanced Second-Harmonic Generation (SHG) by silicon-rich silicon nitride materials over a broad spectral range, and show a maximum conversion efficiency of 4.5 × 10−6 for sub-stoichiometric samples with 46 at. % silicon. The SHG process in silicon nitride thin films is systematically investigated over a range of material stoichiometry and thermal annealing conditions. These findings can enable the engineering of innovative Si-based devices for nonlinear signal processing and sensing applications on a Si platform.
Defining pyromes and global syndromes of fire regimes
Authors: Archibald Sally , Lehmann Caroline E. R. , Gómez-Dans Jose L. , Bradstock Ross A.
Published: April 2013

Fire is a ubiquitous component of the Earth system that is poorly understood. To date, a global-scale understanding of fire is largely limited to the annual extent of burning as detected by satellites. This is problematic because fire is multidimensional, and focus on a single metric belies its complexity and importance within the Earth system. To address this, we identified five key characteristics of fire regimes—size, frequency, intensity, season, and extent—and combined new and existing global datasets to represent each. We assessed how these global fire regime characteristics are related to patterns of climate, vegetation (biomes), and human activity. Cross-correlations demonstrate that only certain combinations of fire characteristics are possible, reflecting fundamental constraints in the types of fire regimes that can exist. A Bayesian clustering algorithm identified five global syndromes of fire regimes, or pyromes. Four pyromes represent distinctions between crown, litter, and grass-fueled fires, and the relationship of these to biomes and climate are not deterministic. Pyromes were partially discriminated on the basis of available moisture and rainfall seasonality. Human impacts also affected pyromes and are globally apparent as the driver of a fifth and unique pyrome that represents human-engineered modifications to fire characteristics. Differing biomes and climates may be represented within the same pyrome, implying that pathways of change in future fire regimes in response to changes in climate and human activity may be difficult to predict.
Effect of Dietary Herbal Supplements on Some Physiological Conditions of Sea BassDicentrarchus labrax
Authors: Yılmaz Sevdan , Ergün Sebahattin , Çelik Ekrem Şanver
Published: April 2013

This study was conducted in order to investigate the effects of dietary thymeThymus vulgaris, rosemaryRosmarinus officinalis, and fenugreekTrigonella foenum graecumas feed additives on total liver fat levels and biometric indices of Sea BassDicentrarchus labrax. Four isonitrogenous (48% crude protein) and isocaloric (21 kJ/g) diets were formulated to contain 0% (control), or 1% of thyme, rosemary, or fenugreek. In a 45‐d feeding trial, 12 fiberglass tanks (140 L) were each stocked with 17 fish (20.43 ± 0.03 g). Herbal supplemented diets significantly decreased the total liver fat, visceral fat index, viscerosomatic index, hepatosomatic index, and increased the spleen–somatic index and bile–somatic index (P < 0.05). In conclusion, the results indicated that a dietary level of 1.0% for thyme, rosemary, or fenugreek could improve some of the physiological parameters of Sea Bass. Thus, this work provides a new perspective for the use of medicinal herbs that can be added to fish feed to improve the status of fish organs. Thyme, rosemary, and fenugreek contain a number of different active components, which possibly play an important role in improving these conditions, but the mechanism by which this is achieved needs further and more detailed study.

Received July 19, 2012; accepted January 15, 2013
When can “principles” support advice on fisheries and environmental management?
Authors: Jennings S.
Published: April 2013

Jennings, S. 2013. When can “principles” support advice on fisheries and environmental management? – ICES Journal of Marine Science, 70: 726–733. Demands for advice on fisheries and environmental management often outstrip scientists' capacity to supply it. The imbalance would be smaller if some of the advice could be based on principles rather than tailored case-by-case analyses, where I define principles as “evidence-based rules that underpin scientific advice on management options and reduce uncertainty about decisions and outcomes with fewer resources than tailored case-by-case analyses”. I consider the role, development, existing and potential uses, strengths and weaknesses of principles in underpinning advice, and how principles might complement methodological innovations and risk assessment. The extent to which principles might replace case-by-case analyses is expected to depend on structures and processes in the management system, particularly the treatment of uncertainty and risk. If advice based on principles is seen as less salient, credible, and legitimate than advice developed from case-by-case analyses then this could lead to political push-back or non-compliance with management measures, transferring costs from the advisory process to other parts of the management system. In general, I propose that principles provide the greatest benefits in a management system when they address complex advisory issues that lead to advice on management measures with relatively small social and economic consequences or when they simplify parts of an advisory process leading to management measures with a range of consequences. Notwithstanding limits on their application, further development and uptake of principles could reduce demands for case-by-case advice on fisheries and environmental management. A formalized challenge, testing, and updating process for principles, supported by an audit trail, would encourage and increase their use. The development of principles would provide a new focus for the targeting, review, and uptake of research. Spatial planning initiatives, the emergence of marine protected area networks, and other changes in management measures can be treated as experiments to inform development and testing of principles.
First Report of Leaf Blight in Chinese Hickory (Carya cathayensis) Caused by Alternaria petroselini in China
Authors: Liu Y. H. , Zhang C. Q. , Xu B. C.
Published: April 2013

Chinese hickory (Carya cathayensis) is one of the important economic forest crops in Zhejiang and Anhui Provinces, China. In 2012, nearly 40% of hickory orchards and 6.8% of hickory trees were affected by leaf blight in Zhejiang. Initial symptoms consisted of small, brown, water-soaked lesions, which subsequently enlarged and developed a black sporulating necrotic center surrounded by a chlorotic halo. Infected leaf samples collected from 25 different orchards in Lin'an and 13 different orchards in Chun'an were surface sterilized with 1.5% sodium hypochlorite for 1.5 min, rinsed in water, plated on 2% potato dextrose agar (PDA), and incubated at 25°C in the dark for 1 week. Single conidium cultures were consistently isolated and cultured on PDA and V8 agar for morphological characterization (1,3). On both agar media, colonies were dark olive brown with smooth margins and concentric rings of sporulation. Conidia were solitary, darkly pigmented, predominantly ovoid-subsphaeroid, and 23 to 52 × 13 to 23 μm with up to six or seven transepta and one to three longisepta. The ribosomal internal transcribed spacers ITS1 and ITS2 of 10 isolates were amplified using primers ITS1/ITS4 on DNA extracted from mycelium and nucleotide sequences showed 100% similarity to that of A. petroselini (GenBank Accession Nos. AY154685.1 and EU807868.1). To confirm pathogenicity, 10 uninfected leaves from each of 10 C. cathayensis trees were sprayed either with a conidia suspension (105 conidia per ml) or with distilled water only to serve as an un-inoculated control. Leaves were subsequently wrapped in plastic bags to retain moisture, and incubated for 48 h. After 1 week, 8 of 10 isolates caused lesions identical to those initially described whereas no symptoms developed on water inoculated leaves. Cultures reisolated from lesions and cultured on PDA exhibited morphological characteristics identical to A. petroselini (1,2,3), confirming Koch's postulates. To our knowledge, this is the first report of leaf blight in C. cathayensis, and this identification would allow producers to identify for appropriate management practices.

References: (1) P. M. Kirk et al. The Dictionary of the Fungi, 10th edition, page 159. CABI Bioscience, UK, 2008. (2) B. M. Pryor et al. Mycologia 94:49, 2002. (3) E. G. Simmons. Alternaria: An Identification Manual. CBS Fungal Biodiversity Centre, Utrecht, The Netherlands, 2007.