bluuebunny/crossref_metadata_2025 huggingface dataset:
Collaborating With the Community: Lessons From a Rural School District
Authors: Walker Anne
Published: August 2012

This article, based on case study research, highlights how a rural school district in the midwestern United States collaborated with local community organizations to meet the needs of English language learners after the district and community experienced rapid ethnic diversification. In particular, the district EL coordinator spearheaded the formation of a diversity committee composed of civic leaders and the heads of social service agencies; the diversity committee developed and supported collaborative projects aimed at meeting the social, academic, and health‐related needs of immigrant youth and their families in a rural community with limited social service resources, and educating community residents about their new immigrant neighbors in order to relieve racial tensions and more easily integrate immigrant youth into the community. The article concludes with recommendations for how schools can maximize outcomes for English language learners through community collaboration.
Cross‐District Collaboration: Curriculum and Professional Development
Authors: Short Deborah J. , Cloud Nancy , Morris Patricia , Motta Julie
Published: August 2012

Secondary English as a second language (ESL) curricula that address four levels of ESL proficiency and prepare students for the English language arts (ELA) curricula and state‐mandated ELA tests are not common. A curriculum jointly developed by two districts is even rarer. Yet two urban districts in Rhode Island undertook such a curriculum development effort that not only created and field‐tested a four‐level, standards‐based ESL curriculum but also developed a four‐subject newcomer curriculum for students with limited formal schooling. This article describes this innovative cross‐district curriculum development project and offers the design process as a model for educators seeking to align ESL standards with ELA standards. It also explains how district administrators pooled resources to provide cross‐district professional development to language and content teachers on effective academic literacy practices for English language learners.
Risk Factor of Surgical Site Infection After Pancreaticoduodenectomy
Authors: Sugiura Teiichi , Uesaka Katsuhiko , Ohmagari Norio , Kanemoto Hideyuki , Mizuno Takashi
Published: August 2012

Background

Although surgical site infection (SSI) following pancreaticoduodenectomy is a common complication, the risk factors remain unclear.

Patients and methods

A retrospective study of 408 consecutive patients undergoing pancreaticoduodenectomy was conducted and the risk factors for SSI were assessed. The bacterial composition was also analyzed.

Results

Sixty‐one patients developed incisional SSI, and 195 developed organ/space SSI. A multivariate analysis identified that length of operation >480 min (odds ratio [OR] 3.22), main pancreatic duct (MPD) ≤3 mm (OR 2.18), and abdominal wall thickness >10 mm (OR 2.16) were significant risk factors for incisional SSI. The development of pancreatic fistula (OR 7.56), use of semi‐closed drainage system (OR 3.68), body mass index >23.5 kg/m2 (OR 3.04), MPD ≤3 mm (OR 2.21), and length of operation >480 min (OR 1.78) were significantly associated with organ/space SSI. Bacterial isolation at the SSI foci revealed that gut‐derived micro‐organisms were the predominant bacterial species.

Conclusions

The presence of pancreatic fistula was the strongest risk factor for organ/space SSI. Efforts to reduce the development of pancreatic fistulas, to decrease length of operation, and to use a closed drainage system would decrease the incidence of SSI following pancreaticoduodenectomy. If SSI that requires antibacterial treatment occurs, then the treatment should target enterobacteria.
Effects of two different instructional formats on scores and reliability of a
script concordance test
Authors: Van den Broek W. E. Sjoukje , Van Asperen Marianne V. , Ten Cate Olle Th. J. , Custers Eug`ene , Valk Gerlof D.
Published: August 2012

The script concordance test (SCT) is designed to assess clinical reasoning by
adapting the likelihood of a case diagnosis, based on provided new information. In the
standard instructions students are asked to exclude alternative diagnoses they have in
mind when answering the questions, but it might be more authentic to include these.
Fifty-nine final-year medical students completed an SCT. Twenty-nine were asked to take
their differential diagnosis into account (adapted instructions). Thirty students were
asked not to consider other diagnoses (standard instructions). All participants were
asked to indicate for each question whether they were confused answering it with the
given instructions (‘confusion indication’). Mean score of the test with the adapted
instructions was 81.5 (SD 3.8) and of the test with the standard instructions 82.9 (SD
5.0) (p = 0.220). Cronbach’s alpha was 0.39 for the adapted instructions and 0.66 for
the standard instructions. The mean number of confusion indications was 4.2 (SD 4.4) per
student for the adapted instructions and 16.7 (SD 28.5) for the standard instructions
(p = 0.139). Our attempt to improve SCTs reliability by modifying the instructions did
not lead to a higher alpha; therefore we do not recommend this change in the
instructional format.
Lift force reduction due to body image of vortex for a hovering flight model
Authors: Wang X. X. , Wu Z. N.
Published: August 2012

The effect of the body on the lift force in hovering flight is studied here by including the effect of image vortex rings (IVRs) in the inviscid vortex ring model proposed by Rayner (J. Fluid Mech., vol. 91, 1979, pp. 697–730) and used by Wang & Wu (J. Fluid Mech., vol. 654, 2010, pp. 453–472) to study lift force due to wakes. The body is treated simply as an equivalent sphere following the data of Ellington (Phil. Trans. R. Soc. Lond.B, vol. 305, 1984a, pp. 17–40). It is shown that the body image reduces the lift by inducing a further downwash near the wing tip and an additional contraction to the real vortex rings (RVRs). The amount of force reduction due to body image is found to grow cubically with relative body size, defined by the equivalent radius relative to the wing span, and approximately linearly with the feathering parameter. ForApisandBombuswith large relative body size and large feathering parameter, the body images reduce lift by an amount near 8 % according to the present simplified analysis.
Who Was He? Reflections on China’s First Medical ‘Naturalist’
Authors: Brown Miranda
Published: August 2012

This paper examines the reasons why Physician He (Yi–He, sixth century BCE) was regarded as a founder in the classical medical tradition of China. By most accounts, Physician He’s importance owes much to his theoretical innovations. In contrast to earlier healers, Physician He purportedly framed the aetiology of illnesses solely in terms of natural causes, as opposed to attributing sickness to gods or demons. In this paper, I reread a famous episode in theCommentary by Zuo, which is often cited as evidence of the physician’s naturalism. By paying close attention to the formal elements of the narrative as well as its larger discursive context, I argue that the standard reading of Physician He falls short. The episode provides little evidence of any secular challenge to religious conceptions of illness, and Physician He was, in fact, patterned after occult experts. A careful look moreover at the reception of Physician He in premodern histories of medicine reveals that the physician was extolled for his attunement to the will of the spirits as well as his powers of examination. Physician He’s reputation as a naturalist furthermore represents a modern interpretation, one that reflects efforts to defend the indigenous medical tradition against its biomedical detractors.
Re-visiting ‘Galen in Tibet’1
Authors: Yoeli-Tlalim Ronit
Published: August 2012

This paper readdresses the assertion found in much secondary literature that Greek medicine was adopted in Tibet in the seventh and eighth centuries. I discuss some of the traces of Galenic medical knowledge in early Tibetan medicine, and raise the question of why Tibetan medical histories who mention Galen give Galenic medicine a much more significant place than is evidenced in the Tibetan medical literature itself. I discuss some historiographical considerations and argue that the centrality given to Galenic medicine is more indicative of the period in which these sources are written than of the period which they presumably describe.
VISIBLE ACTIONS ON FLAG VARIETIES OF TYPE B AND A GENERALISATION OF THE CARTAN DECOMPOSITION
Authors: TANAKA YUICHIRO
Published: August 2012

We give a generalisation of the Cartan decomposition for connected compact Lie groups of type B motivated by the work on visible actions of Kobayashi [‘A generalized Cartan decomposition for the double coset space $(U(n_{1})\times U(n_{2})\times U(n_{3})) \backslash U(n)/ (U(p)\times U(q))$’, J. Math. Soc. Japan59 (2007), 669–691] for type A groups. Suppose that $G$ is a connected compact Lie group of type B, $\sigma $ is a Chevalley–Weyl involution and $L$, $H$ are Levi subgroups. First, we prove that $G=LG^{\sigma }H$ holds if and only if either (I) both $H$ and $L$ are maximal and of type A, or (II) $(G,H)$ is symmetric and $L$ is the Levi subgroup of an arbitrary maximal parabolic subgroup up to switching $H$ and $L$. This classification gives a visible action of $L$ on the generalised flag variety $G/H$, as well as that of the $H$-action on $G/L$ and of the $G$-action on $(G\times G)/(L\times H)$. Second, we find an explicit ‘slice’ $B$ with $\dim B=\mathrm {rank}\, G$ in case I, and $\dim B=2$ or $3$ in case II, such that a generalised Cartan decomposition $G=LBH$holds. An application to multiplicity-free theorems of representations is also discussed.
Egoism or the problem of evil: a dilemma for sceptical theism
Authors: RANCOURT BENJAMIN T.
Published: August 2012

Sceptical theists undermine the argument from evil by claiming that our ability to distinguish between justified and unjustified evil is weak enough that we must take seriously the possibility that all evil is justified. However, I argue that this claim leads to a dilemma: either our judgements regarding unjustified evil are reliable enough that the problem of evil remains a problem, or our judgements regarding unjustified evil are so unreliable that it would be misguided to use them in our decision-making. The first horn undermines theism, while the second undermines our moral decision-making. Thus, sceptical theism is problematic.
Inverse dynamic modeling and analysis of a new caterpillar robotic mechanism by Kane's method
Authors: Wei Hong-Xing , Wang Tian-Miao , Liu Miao , Xiao Jiang-Yang
Published: August 2012

Bionic engineering has been a focus in the field of robotic researches. Inverse dynamic analysis is significant for the determination of dynamic parameters of bionic robots. The present paper uses a newly developed robot modular named Sambot to construct a caterpillar robotic mechanism, and designs a gait of trapezoidal wave locomotion for it. Two open-link models are put forth to simulate the dynamic behavior of such a locomotion. The inverse dynamic differential equations are derived by Kane's method and are then solved numerically by the Runge–Kutta method of the fourth order. Based on the numerical solutions of these differential equations, the applied joint torques required to produce the harmonic trapezoidal wave locomotion are determined finally, providing us important information on the gait control of the caterpillar robotic mechanism. Finally, the theoretical values of the joint torques are applied onto the present caterpillar mechanism to perform a locomotion experiment, which verifies the effectiveness of the present dynamics analysis.
Deformation of plasma bubbles and the associated field aligned current system during substorm recovery phase
Authors: Pang Y. , Lin M. H. , Deng X. H. , Zhou M. , Huang S. Y.
Published: August 2012

Multiple plasma bubbles have been detected by CLUSTER satellites on August 15th 2001 in midtail (∼−18 Re). Those bubbles can be classified into two types. Type‐I bubbles are similar to those bubbles in previous studies [Sergeev et al., 1996; Walsh et al., 2009]. Unlike type‐I bubbles, the trailing parts/tails of type‐II bubbles are much more dynamic than their leading parts/heads and have larger the flux transfer rate. The leading parts of type‐II bubbles were suffering a deceleration process and the interaction between the leading and trailing parts will lead to the intensification of |B| and Bz and also a flow shear layer at the trailing parts. Those shear flows cause the twist of magnetic field line, the enhancement of x and y components magnetic field and the generation of field aligned current system. Enhancement of electric field fluctuations also can be found at the trailing parts of type‐II bubbles. The corresponding ionospheric signatures were also detected by ground geomagnetic stations. We suggested that the type‐II bubbles are bubbles in their late evolution stage and our results are important in understanding the evolution of plasma bubble or fast flow and the transportation of energy from magnetotail to ionosphere.
A small spacecraft mission with large accomplishments
Authors: Baker Daniel N. , Mason Glenn M. , Mazur Joseph E.
Published: August 2012

A remarkable era of space research will end soon when, after 20 years of space‐based observations, the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) spacecraft will reenter Earth's atmosphere. This will result from the resurgence of the Sun's activity and the related increase of atmospheric drag produced by increasing solar ultraviolet radiation. The best estimate is that SAMPEX will succumb to drag forces (and burn up on reentry) in late September 2012, but this could occur as early as August or as late as December 2012 [see Baker et al., 2012]. SAMPEX has been a pacesetting mission since its inception. It was selected in 1989 for flight as NASA's first spacecraft in the “Small Explorer” (SMEX) program [Baker et al., 1993]. The SMEX program was intended both to accomplish forefront science (at a very affordable cost) as well as to provide a training ground in the best space development practices for a new generation of scientists, engineers, and managers. As its full name suggests, SAMPEX was always intended to perform multiple duties and was geared toward making measurements in space of moderate to very high energy particles [see Baker et al., 1993]. A few of the key contributions made by the SAMPEX program are summarized below.
Workshop discusses database for Marcellus water issues
Authors: Brantley Susan L. , Wilderman Candie , Abad Jorge
Published: August 2012

ShaleNetwork 2012 Workshop; State College, Pennsylvania, 23–24 April 2012 The largest source of natural gas in the United States, the Marcellus shale, underlies a 95,000‐square‐mile area from Virginia to New York and from Ohio to Pennsylvania. Since 2005, about 5000 wells have been drilled in Pennsylvania alone, and about 2500 of these are now producing gas. While many welcome the shale gas jobs, others worry about environmental impacts. A workshop was convened at Pennsylvania State University to coordinate the collection of data for water quality and quantity in regions of hydrofracturing. The purpose of the event was to encourage participants to use and contribute data to a growing database of water quality and quantity for regions of shale gas development (www.shalenetwork.org).
Elixir: A history of water and humankind
Authors: Lakshmi Venkat
Published: August 2012

The book Elixir: A History of Water and Humankind outlines the role and profound importance of water in human civilizations and tells the story of how the human race came to discover, understand, and harness water for daily use; control it during floods; and store and use it during droughts. Elixir is based on three broad themes outlined in the preface. The first theme is gravity and the fact that humans discovered the role of gravity in the flow of water and used it to their advantage, whether to store water, divert it for agriculture, or move it away from their homes in the case of floods. The second theme is the connection between water and religious practices followed by humans over the course of history. The book discusses the symbolism that cultures and civilizations have bestowed on water as a religious icon, which heralds humankind's deep‐seated respect for water as the sustenance of human life. The third theme is the connection or balance between technology and sustainability The use of water in daily activities and irrigation has spurred much technological advancement that has helped humans to harness water. The concept of sustainability was present centuries ago with the recycling of water; this helped societies to achieve more with the water they had and avoid facing shortages.
Streamflow changes following the 2010 Chile earthquake
Authors: Balcerak Ernie
Published: August 2012

Changes in stream‐flow and groundwater levels are known to occur following earthquakes, but the mechanisms for stream‐flow changes are not fully understood and vary from one location to another. Mohr et al investigated stream‐flow response in small upland catchments in south central Chile following the magnitude 8.8 Chilean earthquake on 27 February 2010. Stream‐flow initially decreased after the quake, then increased to as much as 400% of pre‐earthquake levels. The increases peaked hours to several days following the earthquake, after which flow gradually declined, though changes were not uniform across all the catchments the authors studied.
New technologies measuring optics of the upper ocean
Authors: Bhattacharya Atreyee
Published: August 2012

Understanding precisely how light propagates across the air‐sea interface and the factors that control this propagation are essential for several studies associated with the upper ocean. For example, estimates of organic activity are based on the amount of chlorophyll present, the number and types of organisms in the upper ocean, and measurements of the number of bubbles in breaking waves (a key factor that controls air‐sea gas exchange). Optical properties of the surface and upper ocean are among the few tools available to scientists interested in understanding physical and chemical processes in the ocean. However, optical properties of the upper ocean vary within milliseconds and over millimeters as well as at longer time and space scales. This is because several factors affect the optical properties of the ocean, ranging from season, cloud cover, fog, aerosols, and wind to ocean turbulence and the organisms and chemicals present in the upper ocean.
Tropical instability waves linked to sea surface salinity anomalies
Authors: Schultz Colin
Published: August 2012

Stretching westward from the South American coast, a tongue of cold water straddles the equator, reaching at times clear across the Pacific Ocean. The behavior of this cold tongue affects the marine ecosystem within its reach and influences the global climate through the El Niño–Southern Oscillation. The Pacific cold tongue is mirrored in the Atlantic, though that version is much weaker and less well defined. In the Pacific, westward propagating waves can periodically radiate outward from the South American coast. Known as tropical instability waves (TIWs), they give the cold tongue's edges a ribbed appearance when observed from space. TIWs are already associated with anomalous sea surface heights and temperatures, surface winds, chlorophyll concentrations, and ocean circulation patterns. Research by Lee et al. provides the first observational evidence of sea surface salinity anomalies associated with TIWs.
Turbulent forces within river plumes affect spread
Authors: Bhattacharya Atreyee
Published: August 2012

When rivers drain into oceans through narrow mouths, hydraulic forces squeeze the river water into buoyant plumes that are clearly visible in satellite images. Worldwide, river plumes not only disperse freshwater, sediments, and nutrients but also spread pollutants and organisms from estuaries into the open ocean. In the United States, the Columbia River—the largest river by volume draining into the Pacific Ocean from North America—generates a plume at its mouth that transports juvenile salmon and other fish into the ocean. Clearly, the behavior and spread of river plumes, such as the Columbia River plume, affect the nation's fishing industry as well as the global economy.
Deformation and stability of over‐pressured wedges: Insight from sandbox models
Authors: Pons A. , Mourgues R.
Published: August 2012

In the well‐known and widely used critical taper model of accretionary wedges, pore pressure is introduced as a first‐order parameter. Despite the fact that the importance of the pore pressure on deformation is largely accepted, the theoretical predictions of the critical model has never been experimentally confirmed for over‐pressured wedges. To fill this gap and to understand how pore pressure may influence deformation within a wedge, we performed scaled experiments under conditions close to the critical taper hypothesis. The wedges were built with a non‐cohesive sand and lied on glass microbeads layer to insure a weak décollement. As we applied horizontally varying fluid pressure at the base of the model, the pore pressure ratioλ was almost constant in the whole wedge. Combining these experiments with an optical image correlation technique (Particle Imaging Velocimetry), we followed the strain in the model during the shortening. We highlighted three different modes of deformation which are strongly influenced by the pressure ratio, λ, and the wedge taper. Although we found a pretty good agreement between the experimental observations and the critical taper model predictions, it appears that the transition between sub‐critical and super‐critical conditions is not sharp as described by the critical taper model but continuous. The distance to the critical taper condition, which depends on both the topographic angle,α and the pressure ratio, λ seems to control the propagation rate of the décollement and the strain localization within the wedge.
Ground‐based aerosol optical depth trends at three high‐altitude sites in Switzerland and southern Germany from 1995 to 2010
Authors: Nyeki S. , Halios C. H. , Baum W. , Eleftheriadis K. , Flentje H. , Gröbner J. , Vuilleumier L. , Wehrli C.
Published: August 2012

Ground‐based aerosol optical depth (AOD) climatologies at three high‐altitude sites in Switzerland (Jungfraujoch and Davos) and Southern Germany (Hohenpeissenberg) are updated and re‐calibrated for the period 1995–2010. In addition, AOD time series are augmented with previously unreported data, and are homogenized for the first time. Trend analysis revealed weak AOD trends (λ = 500 nm) at Jungfraujoch (JFJ; +0.007 decade−1), Davos (DAV; +0.002 decade−1) and Hohenpeissenberg (HPB; −0.011 decade−1) where the JFJ and HPB trends were statistically significant at the 95% and 90% confidence levels. However, a linear trend for the JFJ 1995–2005 period was found to be more appropriate than for 1995–2010 due to the influence of stratospheric AOD which gave a trend −0.003 decade−1 (significant at 95% level). When correcting for a recently available stratospheric AOD time series, accounting for Pinatubo (1991) and more recent volcanic eruptions, the 1995–2010 AOD trends decreased slightly at DAV and HPB but remained weak at +0.000 decade−1 and −0.013 decade−1 (significant at 95% level). The JFJ 1995–2005 AOD time series similarly decreased to −0.003 decade−1(significant at 95% level). We conclude that despite a more detailed re‐analysis of these three time series, which have been extended by five years to the end of 2010, a significant decrease in AOD at these three high‐altitude sites has still not been observed.
Grid-connectivity of remote isolated islands—A proposition in Indian context
Authors: Das Aurobi , Balakrishnan V.
Published: August 2012

This paper has analyzed the cases of Moushuni Island at Sundarban of 24 Parganas South of West Bengal, India. The proposition is to find out the possibility of grid-connectivity of isolated remote islands which is under rural electrification scheme by hybrid renewable energies under Jawaharlal Nehru National Solar Mission of India. In these rural electrification program, grid extension can be the best option if the grid is reliable, the rural community rather big and in proximity to the grid. In many circumstances, a strong case for mini-grids based on hybrid systems can be made. Scattered communities and isolated houses are well served by solar and small hydro (where available) or small wind energy systems. By feeding renewable electricity to the utility grid through grid-connected hybrid renewable energy system, during time of peak demand, sufficient electrical loads can be shed to prevent turning on a coal or natural gas-fired plant and therefore save CO2 emissions and potentially energy import costs, replacing fossil fuels. But there is a barrier for grid-connectivity for isolated island, which can be overcome by feed-in-tariff policy implementation for renewables. Also, feed-in-tariff for mini-grids is a promising approach for linking off-grid and grid-connected renewable energy support. Also, most intelligent controller for grid interactive operation of solar photovoltaic-wind-bio hybrid energy system at Moushuni Island is proposed. This intelligent controller will switch from various renewable resources like solar-wind-biomass through change over switch panel to find out optimized hybrid renewable energy system. Malda district of West Bengal, India is a vision towards smart-grid city towards sustainable future, where rural consumers can upgrade their quality of life through solar energy resource. This paper also illustrated the socio-economic and environmental benefits and social costing of adopting renewables future for India. Cost proposition for integrating distributed renewable energy sources-solar energy to electricity grid has been analyzed along with the feasibility studies for factors responsible for cost/unit reduction. The feasibility studies for social, economic, and environmental benefits of renewables have been discussed along with justifications for hybrid renewable vs stand alone-photovoltaic and other types of renewable energy systems along with the comparative analysis of economic costing of installation of various types of renewable energy systems.
Analysis of stable periodic orbits in the one dimensional linear piecewise-smooth discontinuous map
Authors: Rajpathak Bhooshan , Pillai Harish K. , Bandyopadhyay Santanu
Published: August 2012

In this paper, we consider one dimensional linear piecewise-smooth discontinuous maps. It is well known that stable periodic orbits exist for such maps, in some parameter region. It is also known that the corresponding bifurcation phenomena (termed as period adding bifurcation) exhibit a special structure. In the last couple of years, several authors have analyzed this structure using border collision bifurcation curves and given the characterization for various parameter regions. In this paper, we have analyzed a specific parameter range employing a different approach. We show that this approach enables one to pose some interesting questions like: what is the number of distinct periodic orbits of any given cardinality? We prove that there are precisely ϕ(n) distinct orbits of period n, where ϕ is the Euler’s totient function. We propose an algorithm which calculates the location of fixed points of all these ϕ(n) distinct orbits and gives the precise range of existence of these orbits with respect to the parameters. Further, we show how the amount of computations required to find these ranges of existence can be optimized.
A methodology for calibrating wavelength dependent spectral resolution for crystal spectrometers
Authors: Loisel G. , Bailey J. E. , Rochau G. A. , Dunham G. S. , Nielsen-Weber L. B. , Ball C. R.
Published: August 2012

High quality absorption spectroscopy measurements were recently achieved at the Sandia National Laboratories Z facility in the soft x-ray range. Detailed spectral resolution knowledge is a key requirement for their interpretation. We present a methodology for measuring the wavelength dependent crystal spectral resolution, with a particular focus on the 7–17 Å range. We apply this procedure to the case of 1st order resolution of a potassium acid phthalate (KAP) convex crystal spectrometer. One calibration issue is that inferring the crystal resolution requires that the x-ray source emission feature widths and spectral profiles are known. To this aim, we resolve Manson x-ray source Si, Al, and Mg Kα line profiles using a KAP crystal spectrometer in 2nd order to achieve relatively high resolution. This information is exploited to measure 1st order KAP resolving powers λ/Δλ∼1100–1300 in the 7–10 Å wavelength range.
New solvable discrete-time many-body problem featuring several arbitrary parameters
Authors: Calogero F. , Leyvraz F.
Published: August 2012

A new dynamical system interpretable as a discrete-time many-body problem is identified, and it is shown how its initial-value problem can be solved by purely algebraic operations.
Neutron scattering studies of K3H(SO4)2 and K3D(SO4)2: The particle-in-a-box model for the quantum phase transition
Authors: Fillaux François , Cousson Alain
Published: August 2012

In the crystal of K3H(SO4)2 or K3D(SO4)2, dimers SO4⋅⋅⋅H⋅⋅⋅SO4 or SO4⋅⋅⋅D⋅⋅⋅SO4 are linked by strong centrosymmetric hydrogen or deuterium bonds whose O⋅⋅⋅O length is ≈2.50 Å. We address two open questions. (i) Are H or D sites split or not? (ii) Is there any structural counterpart to the phase transition observed for K3D(SO4)2 at Tc ≈ 85.5 K, which does not exist for K3H(SO4)2? Neutron diffraction by single-crystals at cryogenic or room temperature reveals no structural transition and no resolvable splitting of H or D sites. However, the width of the probability densities suggest unresolved splitting of the wavefunctions suggesting rigid entities HL1/2 −HR1/2 or DL1/2 −DR1/2 whose separation lengths are lH ≈ 0.16 Å or lD ≈ 0.25 Å. The vibrational eigenstates for the center of mass of HL1/2 −HR1/2 revealed by inelastic neutron scattering are amenable to a square-well and we suppose the same potential holds for DL1/2 −DR1/2. In order to explain dielectric and calorimetric measurements of mixed crystals K3D(1 − ρ)Hρ(SO4)2 (0 ⩽ ρ ⩽ 1), we replace the classical notion of order-disorder by the quantum notion of discernible (e.g., DL1/2 −DR1/2) or indiscernible (e.g., HL1/2 −HR1/2) components depending on the separation length of the split wavefunction. The discernible-indiscernible isostructural transition at finite temperatures is induced by a thermal pure quantum state or at 0 K by ρ.
High-speed acousto-optic shutter with no optical frequency shift
Authors: Schwenger W. J. , Higbie J. M.
Published: August 2012

Acousto-optic modulators are widely used for rapid switching and shuttering of laser beams. In many applications, the concomitant frequency shift is undesirable and must be compensated for elsewhere in the system. Here we present a simple method of achieving rapid laser power switching without an accompanying laser frequency shift. The demonstrated acousto-optic shutter achieves a switching time of around 25 ns, an extinction ratio of 46 dB, and efficiency comparable to a conventional double-pass acousto-optical modulator configuration.
Achieving partial decoherence in surface hopping through phase correction
Authors: Shenvi Neil , Yang Weitao
Published: August 2012

Fewest-switches surface hopping is one of the simplest and most popular methods for the computational study of nonadiabatic processes. Recently, a very simple phase correction was introduced to the traditional surface hopping algorithm, substantially improving its accuracy with essentially no associated computational cost [N. Shenvi, J. E. Subotnik, and W. Yang, J. Chem. Phys. 135, 024101 (2011)]10.1063/1.3603447. In this paper, we show that we can modify our phase-corrected algorithm slightly such that it takes into account one type of decoherence, again with no additional computational cost. We apply our algorithm to two existing model problems, demonstrating that it can indeed capture one particular type of decoherence without any of the sophisticated machinery of alternative algorithms.
The architecture of dynamic reservoir in the echo state network
Authors: Cui Hongyan , Liu Xiang , Li Lixiang
Published: August 2012

Echo state network (ESN) has recently attracted increasing interests because of its superior capability in modeling nonlinear dynamic systems. In the conventional echo state network model, its dynamic reservoir (DR) has a random and sparse topology, which is far from the real biological neural networks from both structural and functional perspectives. We hereby propose three novel types of echo state networks with new dynamic reservoir topologies based on complex network theory, i.e., with a small-world topology, a scale-free topology, and a mixture of small-world and scale-free topologies, respectively. We then analyze the relationship between the dynamic reservoir structure and its prediction capability. We utilize two commonly used time series to evaluate the prediction performance of the three proposed echo state networks and compare them to the conventional model. We also use independent and identically distributed time series to analyze the short-term memory and prediction precision of these echo state networks. Furthermore, we study the ratio of scale-free topology and the small-world topology in the mixed-topology network, and examine its influence on the performance of the echo state networks. Our simulation results show that the proposed echo state network models have better prediction capabilities, a wider spectral radius, but retain almost the same short-term memory capacity as compared to the conventional echo state network model. We also find that the smaller the ratio of the scale-free topology over the small-world topology, the better the memory capacities.
Kinetic model of electric potentials in localized collisionless plasma structures under steady quasi-gyrotropic conditions
Authors: Schindler K. , Birn J. , Hesse M.
Published: August 2012

Localized plasma structures, such as thin current sheets, generally are associated with localized magnetic and electric fields. In space plasmas localized electric fields not only play an important role for particle dynamics and acceleration but may also have significant consequences on larger scales, e.g., through magnetic reconnection. Also, it has been suggested that localized electric fields generated in the magnetosphere are directly connected with quasi-steady auroral arcs. In this context, we present a two-dimensional model based on Vlasov theory that provides the electric potential for a large class of given magnetic field profiles. The model uses an expansion for small deviation from gyrotropy and besides quasineutrality it assumes that electrons and ions have the same number of particles with their generalized gyrocenter on any given magnetic field line. Specializing to one dimension, a detailed discussion concentrates on the electric potential shapes (such as “U” or “S” shapes) associated with magnetic dips, bumps, and steps. Then, it is investigated how the model responds to quasi-steady evolution of the plasma. Finally, the model proves useful in the interpretation of the electric potentials taken from two existing particle simulations.
Low intensity dust ion-acoustic shock waves due to dust charge fluctuation in a nonextensive dusty plasma
Authors: Alinejad H. , Shahmansory M.
Published: August 2012

The properties of low intensity dust ion acoustic shock waves are studied in a charge varying dusty plasma with nonextensive electrons. Owing to the departure from the Maxwellian electron distribution to a nonextensive one, the modified electrostatic charging of a spherical dust particle in plasma with ion streaming speed is considered. Based on the weakly nonlinear analysis, a new relationship between the low intensity localized disturbances and nonextensive electrons is derived. It is found that both strength and steepness of shock structures arise as the electrons evolve far from their thermodynamic equilibrium in such plasma with parameter ranges corresponding to Saturn’s rings. It is also shown that the ion temperature and population of electrons reduce the possibility of the formation of the shock profile.
Changes in organic compound composition in soil following heating to maximum soil water repellency under anoxic conditions
Authors: Atanassova I. , Doerr S. H. , Bryant R.
Published: August 2012

Environmental contextHeating of soils under wildfires can substantially reduce their ability to absorb rainfall, causing reduced vegetation recovery and increased erosion and flooding. This study examines, for the first time, the chemical changes in soil organic matter associated with heating in the oxygen-limited conditions typical under many wildfires. There was a noticeable tendency for production of non-polar compounds, which may ultimately contribute to a more persistent form of soil water repellency with important implications for managing fire affected terrain.
AbstractSoil heating, as experienced during wildfires or management burns, can lead to extreme soil water repellency (WR). Previous work has focussed on the chemical composition of soil organic matter (SOM) that may be associated with WR in natural soil samples or samples heated in air. Under wildfires, however, oxygen supply is typically reduced and previous work has shown that the extreme WR induced under such conditions resists eventual destruction at temperatures ~200 °C higher than that of the same soil heated in air. This study examines, for the first time, the chemical changes in SOM associated with extreme WR following heating under oxygen limited conditions. Extracts obtained by accelerated solvent extraction (ASE), using mixtures of isopropyl alcohol/aqueous ammonia (IPA/NH3) and dichloromethane/methanol (DCM/MeOH), were analysed using gas chromatography–mass spectrometry (GC/MS). The data were compared with the SOM composition of the same soil unheated and following heating in air. In the absence of oxygen during soil heating, phthalic acid esters, substituted benzaldehydes, unsaturated amides and organophosphate esters were produced. In comparison with extracts of the same soil heated in air, there was a decreased methoxyphenol/phenol ratio, suggesting progressive demethoxylation and synthesis of new aromatic structures likely to promote extreme WR in soil.
Trace metal speciation predictions in natural aquatic systems: incorporation of dissolved organic matter (DOM) spectroscopic quality
Authors: Mueller Kristin K. , Lofts Stephen , Fortin Claude , Campbell Peter G. C.
Published: August 2012

Environmental contextTo assess the risk posed by environmental contaminants such as metals, one needs to be able to identify the key chemical species that prevail in natural waters. One of the recognised stumbling blocks is the need to quantify the influence of heterogeneous dissolved organic matter (DOM). Here we explore the possibility of using the optical signature of DOM to determine its quality, to alleviate the need to make assumptions about its metal-binding properties and to improve the prediction of trace metal species distributions in natural waters.
AbstractTo calculate metal speciation in natural waters, modellers must choose the proportion of dissolved organic matter (DOM) that is actively involved in metal complexation, defined here as the percentage of active fulvic acid (FA); to be able to estimate this proportion spectroscopically would be very useful. In the present study, we determine the free Cd2+, Cu2+, Ni2+ and Zn2+ concentrations in eight Canadian Shield lakes and compare these measured concentrations to those predicted by the Windermere Humic Aqueous Model (WHAM VI). For seven of the eight lakes, the measured proportions of Cd2+ and Zn2+ fall within the range of values predicted by WHAM; the measured proportion of Cu2+ falls within this range for only half of the lakes sampled, whereas for Ni, WHAM systematically overestimated the proportion of Ni2+. With the aim of ascribing the differences between measured and modelled metal speciation to variations in DOM quality, the percentage of active FA needed to fit modelled and measured free metal concentrations was compared with the lake-to-lake variation in the spectroscopic quality of the DOM, as determined by absorbance and fluorescence measurements. Relationships between the percentage of active FA and DOM quality were apparent for Cd, Cu, Ni and Zn, suggesting the possibility of estimating the percentage of active FA spectroscopically and then using this information to refine model predictions. The relationships for Ni differed markedly from those observed for the other metals, suggesting that the DOM binding sites active in Cd, Cu and Zn complexation are different from those involved in Ni complexation. To our knowledge, this is the first time that such a distinction has been resolved in natural water samples.
Currently used pesticides, hexachlorobenzene and hexachlorocyclohexanes in the air and seawater of the German Bight (North Sea)
Authors: Zhong Guangcai , Xie Zhiyong , Möller Axel , Halsall Crispin , Caba Armando , Sturm Renate , Tang Jianhui , Zhang Gan , Ebinghaus Ralf
Published: August 2012

Environmental contextThe occurrence of pesticides in remote areas such as high mountains and the Arctic demands an understanding of their regional environmental fate. We investigate the levels and sources of currently used pesticides and legacy pesticides in the air and seawater of the German Bight. Volatilisation from local surfaces and long-range transport were the major sources of these chemicals to the air, whereas riverine input and atmospheric deposition by air–seawater exchange were the main sources of these chemicals to the seawater.
AbstractSurface seawater and air samples collected from the German Bight (North Sea) in March, May and July 2010 were analysed for hexachlorobenzene (HCB) and hexachlorocyclohexanes (HCHs), five currently used pesticides (CUPs) (trifluralin, endosulfan, chlorpyrifos, dacthal and quintozene) and pentachloroanisole (metabolite). Volatilisation from local surfaces was considered to be the main source of these chemicals to the air (excluding trifluralin). Long-range transport from Western Europe partly contributed to the higher air concentrations observed in July whereas riverine input was the main source for HCHs and pentachloroanisole in seawater in March. Air–sea gas exchange of HCB and α-HCH in the German Bight was found to be near equilibrium, probably reflecting the past use of these chemicals, their wide dispersal in the environment and lack of contemporary use. Deposition of target compounds from the air to seawater was observed to be much higher in July compared with depositional fluxes for March and May, except for chlorpyrifos (with volatilisation fluxes in all sampling periods: ~25 ng m–2 day–1). Concentrations of trifluralin in seawater appear to have decreased since its restriction of use in European Union member states, with net volatilisation from seawater observed in March (flux: 6.3 ± 7.2 ng m–2 day–1). With the exception of chlorpyrifos, our results indicate that volatilisation from local sources combined with long-range transport from Western Europe and subsequent deposition are important pathways for these compounds to German Bight seawater during summer periods.
Variability in reproductive investment of skipjack tuna (Katsuwonus pelamis) in relation to the ocean - climate dynamics in the tropical eastern Indian Ocean
Authors: Kanaji Yu , Tanabe Toshiyuki , Watanabe Hikaru , Oshima Tatsuki , Okazaki Makoto
Published: August 2012

The Indian Ocean is characterised by significant climatic and oceanographic variability such as the seasonal monsoon and the decadal and inter-annual oscillation of the Indian Ocean Dipole (IOD). Understanding the effects of ocean–climate variability on marine top predators is important for both fisheries and ecosystem management. To test the hypothesis that variability in surface and subsurface temperature affects the annual reproductive cycles of skipjack tuna (Katsuwonus pelamis) in the tropical eastern Indian Ocean, we examined the seasonal and inter-annual variations of the gonadosomatic index (GSI) and determined hatch date by using otolith microstructure analysis. The GSI tended to be higher in January–February during the north-eastern monsoon when seawater cooling at the subsurface layer is induced by the seasonal inflow of the South Equatorial Countercurrent (SECC). The mode of the hatch-month distribution was also detected in that season. The generalised linear model (GLM) resulted in a dome-shaped quadratic relationship, with a peak GSI between 24°C and 26°C occurring at a depth of 50 m during austral summer. These findings indicate that seasonal monsoons and associated changes in oceanographic conditions strongly affect the energy-allocation pattern of skipjack tunas.
Genetic catch verification to support recovery plans for deepsea gulper sharks (genus Centrophorus, family Centrophoridae) - an Australian example using the 16S gene
Authors: Daley Ross K. , Appleyard Sharon A. , Koopman Mathew
Published: August 2012

Several species of Centrophorus have been harvested beyond sustainable limits in the Pacific, Atlantic, and Indian Oceans. Effective monitoring of current recovery plans in Australia requires the implementation of a catch data verification plan. The utility of the 16S mitochondrial gene region was evaluated for discriminating among seven recognised morphologically similar Centrophorus species caught in commercial fisheries in Australia and Indonesia. The 16S gene amplified consistently, was sequenced in all individuals tested, and was able to distinguish all species with sufficient resolution for routine testing, apart from C. harrissoni and C. isodon. These two allopatric species were distinguishable using four types of external morphological characters. We conclude that the 16S gene is a robust marker suitable for fishery catch verification of Centrophorus, particularly for Australian samples collected under non-ideal conditions for preservation. When combined with morphological characters, this approach is a reliable and efficient system for routine testing. Trials with the CO1 mtDNA gene found that specialised primers are needed; trials with the Cytb mtDNA gene found this marker is sensitive to preservation problems. Future development of the 16S and CO1 markers are likely to contribute to resolution of taxonomic problems within the Centrophoridae.