bluuebunny/crossref_metadata_2025 huggingface dataset:
In situ observation of x-ray irradiation effect by using a multiwave x-ray diffraction phenomenon
Authors: Yashiro Wataru , Yoda Yoshitaka , Miki Kazushi , Takahashi Toshio
Published: December 2011

In situ observation of the complex scattering amplitude of x-ray specular reflection (amplitude reflectivity) was performed by using a method with a multiwave x-ray diffraction phenomenon. The method can be applied to the noncrystalline layers on a single crystal and allows us to determine its amplitude reflectivity with only a 0.01 degree of crystal rotation, that is, the area irradiated by the incident x rays is almost unchanged during the measurement. We used this method to observe an irradiation effect induced by monochromatic synchrotron x-rays that occurred on a Si(001) single crystal covered with a native oxide layer. The obtained time evolution of the amplitude reflectivities exhibited counterclockwise behavior in the complex plane, indicating that the thickness of the noncrystalline layer on the crystalline substrate was increased by the irradiation.
In situ imaging of orthoclase–aqueous solution interfaces with x-ray reflection interface microscopy
Authors: Fenter P. , Lee S. S. , Zhang Z. , Sturchio N. C.
Published: December 2011

The use of x-ray reflection interface microscopy (XRIM) to image molecular-scale topography at the aqueous–solid interface, in situ, is described. Specifically, we image interfacial topography of the orthoclase-(001)–aqueous solution interface at room temperature and describe the challenges associated with in situ XRIM imaging. The measurements show that the reflectivity signal for in situ XRIM measurements is substantially smaller than that for ex situ measurements, because of both intrinsic and extrinsic factors. There is also a systematic temporal reduction in the image intensity with increasing x-ray dose, revealing that interaction of the focused x-ray beam with the orthoclase interfaces leads to interfacial perturbations, presumably in the form of surface roughening. This image fading is localized to the x-ray beam footprint, suggesting that the primary damage mechanism is initiated by photoelectrons produced by x-ray beam absorption near the substrate–electrolyte interface. Finally, the role of aqueous solution composition in controlling the sensitivity of the orthoclase surface to x-ray beam-induced effects is explored. A substantial increase in the orthoclase (001) surface stability was observed in solutions having elevated ionic strength, apparently as a result of the reduced lifetime of radiation chemistry products at these conditions.
Molecular dynamics study of the processes in the vicinity of the n-dodecane vapour/liquid interface
Authors: Xie Jian-Fei , Sazhin Sergei S. , Cao Bing-Yang
Published: December 2011

Molecular dynamics (MD) simulation is used to study the evaporation and condensation of n-dodecane (C12H26), the closest approximation to Diesel fuel. The interactions in chain-like molecular structures are modelled using an optimised potential for liquid simulation (OPLS). The thickness of the transition layer between the liquid and vapour phases at equilibrium is estimated. It is shown that molecules at the liquid surface need to obtain relatively large translational energy to evaporate. The vapour molecules with large translational energy can easily penetrate deeply into the transition layer and condense in the liquid phase. The evaporation/condensation coefficient is estimated and the results are shown to be compatible with the previous estimates based on the MD analysis and the estimate based on the transition state theory. The velocity distribution functions of molecules at the liquid-vapour equilibrium state are found in the liquid phase, interface, and the vapour phase. These functions in the liquid phase and at the interface are shown to be close to isotropic Maxwellian for all velocity components. The velocity distribution function in the vapour phase is shown to be close to bi-Maxwellian with the temperature for the distribution normal to the interface being larger than the one for the distribution parallel to the interface.
Equilibrium and quasi-equilibrium spin-electrical effect in the system of electrons floating on the surface of liquid helium
Authors: Gurzhi R. N , Kalinenko A. N. , Kopeliovich A. I. , Yanovskiy A. V.
Published: December 2011

It is shown that a potential difference, the value of which depends on the spin state of electrons, appears in the vicinity of the system of electrons floating on the surface of liquid helium in an inhomogeneous magnetic field.
Charge ordering and intermediate range order in ammonium ionic liquids
Authors: Siqueira Leonardo J. A. , Ribeiro Mauro C. C.
Published: December 2011

Molecular dynamics simulations were performed for ionic liquids based on the bis(trifluoromethylsulfonyl)imide anion, [NTf2], and ammonium cations with increasing length of the alkyl chain and ether functionalized chain. The signature of charge ordering is a sharp peak in the charge–charge structure factor, Sqq(k), whose intensity is barely affected for longer carbon chain in tetraalkylammonium systems, but decreases in ether functionalized ionic liquids. The first sharp diffraction peak (FSDP) and the corresponding intermediate range order (IRO) are observed in the total S(k) of ionic liquids containing ammonium cations with relatively long chains. The intensity of the FSDP is lower in the total S(k) of the ether derivative in comparison with the tetraalkylammonium counterpart of the same chain length. It is shown that the nature of the IRO is structural heterogeneity of polar and non-polar domains, even though domains defined by chain interactions in the ether derivatives become more polar. Charge correlation in the ether derivative is modified because cations can be coordinated by oxygen atoms of the ether functionalized chain of neighboring cations.
Selective zinc ion detection by functionalised ZnO nanorods with ionophore
Authors: Ibupoto Z. H. , Usman Ali Syed M. , Chey C. O. , Khun K. , Nur O. , Willander Magnus
Published: December 2011

In this paper, highly dense and well aligned single-crystal zinc oxide nanorods were grown along the c-axis on a gold coated glass substrate using a low temperature aqueous chemical growth approach. The prepared ZnO nanorods were functionalized with plastic membrane coatings containing specific ionophore (12-crown-4) which is highly selective to zinc ions (Zn+2). The electrochemical response of the sensor was found to be linear over a relatively wide logarithmic concentration range from 1 μM to 100 mM. The proposed sensor showed a good linearity with a high sensitivity of ∼35 mV/decade for sensing Zn+2 ions. A fast response time of less than 5 s with a good selectivity, repeatability, reproducibility, and negligible response to common interferents ions such as calcium (Ca2+), magnesium (Mg2+), or potassium (K+), and iron (Fe+3) and copper (Cu+2) was also demonstrated. Moreover, the proposed sensor showed good stoichiometric results for potentiometric titration.
The instability of the boundary layer over a disk rotating in an enforced axial flow
Authors: Hussain Z. , Garrett S. J. , Stephen S. O.
Published: December 2011

We consider the convective instability of stationary and traveling modes within the boundary layer over a disk rotating in a uniform axial flow. Complementary numerical and high Reynolds number asymptotic analyses are presented. Stationary and traveling modes of type I (crossflow) and type II (streamline curvature) are found to exist within the boundary layer at all axial flow rates considered. For low to moderate axial flows, slowly traveling type I modes are found to be the most amplified, and quickly traveling type II modes are found to have the lower critical Reynolds numbers. However, near-stationary type I modes are expected to be selected due to a balance being struck between onset and amplification. Axial flow is seen to stabilize the boundary layer by increasing the critical Reynolds numbers and reducing amplification rates of both modes. However, the relative importance of type II modes increases with axial flow and they are, therefore, expected to dominate for sufficiently high rates. The application to chemical vapour deposition (CVD) reactors is considered.
Photoelectron spectroscopic study on the electronic structures of the dental gold alloys and their interaction with L-cysteine
Authors: Ogawa Koji , Tsujibayashi Toru , Takahashi Kazutoshi , Azuma Junpei , Ichimiya Masayoshi , Fujimoto Hitoshi , Sumimoto Michinori , Kamada Masao
Published: December 2011

The valence electronic structures of the dental gold alloys, type 1, type 3, and K14, and their interaction with L-cysteine have been studied by ultraviolet photoelectron spectroscopy with synchrotron radiation. It was found that the electronic structures of the type-1 and type-3 dental alloys are similar to that of polycrystalline Au, while that of the K14 dental alloy is much affected by Cu. The peak shift and the change in shape due to alloying are observed in all the dental alloys. It is suggested that the new peak observed around 2 eV for the L-cysteine thin films on all the dental alloys may be due to the bonding of S 3sp orbitals with the dental alloy surfaces, and the Cu–S bond, as well as the Au–S and Au–O bonds, may cause the change in the electronic structure of the L-cysteine on the alloys.
Sound velocity, temperature, melting along the Hugoniot and equation of state for two porosity aluminums
Authors: Song Ping , Cai Ling-cang , Wang Qing-song , Zhou Xian-ming , Li Xinzhu , Zhang Yi , Yuan Shuai , Weng Ji-dong , Li Jia-bo
Published: December 2011

The shock-induced melting of porous aluminum samples of two different porosities occurred at pressures about 116 GPa and 81 GPa based on measurements of the sound velocity and shock temperature. An equation of state for porous aluminum was developed from these results, and the anharmonic parameters were determined quantitatively. The variation in the shock melting pressure, melting temperature, and anharmonic parameter with porosity are explored.
Self-heating of metallic carbon nanotube bundles in the regime of the Luttinger-liquid conductivity
Authors: Danilchenko B. A. , Tripachko N. A. , Voytsihovska E. A. , Obukhov I. A. , Yaskovets I. I. , Sundqvist B.
Published: December 2011

The conductivity of bundles of carbon single-walled nanotubes with metallic conductivity (metallic nanotubes) is investigated over the wide temperature range 4.2–330 K and electrical fields up to 50 V. The usage of short electrical pulses of the duration of 10 ns allowed to avoid an influence of a self-heating of the investigated structures on current-voltage characteristics. It is shown that the temperature dependence of conductivity is described by the power function G∝Tα. At helium temperatures the asymptotic dependence of current on applied voltage is close to J∝V1+α with α = 0.45. From comparison of the obtained results of measurements with calculations, it is shown that the conductivity of nanotube bundles is well described within the theory of the Luttinger-liquid conductivity for one-dimensional conductors. The self-heating of the carbon nanotube bundles was observed in the case of measurements in the regime of dc current. A method for determination of the self-heating temperature of nanotube bundles as a function of an applied electrical field is proposed. The power dependence of the self-heating temperature on voltage T∝Vp with the exponent p = 2.1 was observed above some threshold voltage in the temperature range 4.2–200 K. Above 200 K the exponent decreased down to p = 1.35.
Electrostatic interactions in finite systems treated with periodic boundary conditions: Application to linear-scaling density functional theory
Authors: Hine Nicholas D. M. , Dziedzic Jacek , Haynes Peter D. , Skylaris Chris-Kriton
Published: December 2011

We present a comparison of methods for treating the electrostatic interactions of finite, isolated systems within periodic boundary conditions (PBCs), within density functional theory (DFT), with particular emphasis on linear-scaling (LS) DFT. Often, PBCs are not physically realistic but are an unavoidable consequence of the choice of basis set and the efficacy of using Fourier transforms to compute the Hartree potential. In such cases the effects of PBCs on the calculations need to be avoided, so that the results obtained represent the open rather than the periodic boundary. The very large systems encountered in LS-DFT make the demands of the supercell approximation for isolated systems more difficult to manage, and we show cases where the open boundary (infinite cell) result cannot be obtained from extrapolation of calculations from periodic cells of increasing size. We discuss, implement, and test three very different approaches for overcoming or circumventing the effects of PBCs: truncation of the Coulomb interaction combined with padding of the simulation cell, approaches based on the minimum image convention, and the explicit use of open boundary conditions (OBCs). We have implemented these approaches in the ONETEP LS-DFT program and applied them to a range of systems, including a polar nanorod and a protein. We compare their accuracy, complexity, and rate of convergence with simulation cell size. We demonstrate that corrective approaches within PBCs can achieve the OBC result more efficiently and accurately than pure OBC approaches.
Infrared photocurrent with one- and two-photon absorptions in a double-barrier quantum well system
Authors: Degani Marcos H. , Maialle Marcelo Z. , Farinas Paulo F. , Studart Nelson
Published: December 2011

We present a theoretical investigation of a double-barrier quantum-well infrared photodetector (QWIP) having two-color selectivity. The quantum well is placed between a pair of potential barriers in order to increase selectivity through modulation of the continuum states. This also leads to a potential decrease in the dark current. Calculations are carried in the effective-mass approximation using a single-electron hamiltonian. The approach used to obtain the photocurrent yields the observation of single as well as many-photon transitions in a unified manner, by naturally accounting for real and virtual processes through intermediate states that take part in the generation of photocurrent. The two-color selectivity of the calculated photocurrent spectra comes from both one- and two-photon transitions. The performance of the system studied is compared to the results for the isolated quantum well and the advantages of the double barrier are pointed out.
Magnetic properties of L1-FePt/permalloy exchange-spring films
Authors: Utsumiya Kazutoshi , Seki Takeshi , Takanashi Koki
Published: December 2011

In-plane magnetized L10-FePt/permalloy (Py) bilayer films were prepared on an MgO (110) single crystal substrate, and their exchange-spring behavior was investigated. The FePt single layer deposited at the substrate temperature (Ts) of 300 °C showed large uniaxial magnetic anisotropy in the in-plane direction. However, the coercivity (Hc) was reduced remarkably when the FePt layer of Ts = 300 °C was combined with the Py layer, resulting in no observation of exchange-spring behavior. By elevating Ts up to 450 °C, on the other hand, Hc for the FePt layer was enhanced. Owing to the increase in Hc for Ts = 450 °C, spring back was definitely observed in the minor magnetization curves for the FePt/Py bilayers. This suggests the existence of the twisted magnetic structure in the Py layer. The dependence of exchange-spring behavior on the Py layer thickness was systematically examined. The experimental results were also discussed in comparison with numerical calculations.
Mean field theory of charged dendrimer molecules
Authors: Lewis Thomas , Pryamitsyn Victor , Ganesan Venkat
Published: December 2011

Using self-consistent field theory (SCFT), we study the conformational properties of polyelectrolyte dendrimers. We compare results for three different models of charge distributions on the polyelectrolytes: (1) a smeared, quenched charge distribution characteristic of strong polyelectrolytes; (2) a smeared, annealed charge distribution characteristic of weak polyelectrolytes; and (3) an implicit counterion model with Debye-Huckel interactions between the charged groups. Our results indicate that an explicit treatment of counterions is crucial for the accurate characterization of the conformations of polyelectrolyte dendrimers. In comparing the quenched and annealed models of charge distributions, annealed dendrimers were observed to modulate their charges in response to the density of polymer monomers, counterions, and salt ions. Such phenomena is not accommodated within the quenched model of dendrimers and is shown to lead to significant differences between the predictions of quenched and annealed model of dendrimers. In this regard, our results indicate that the average dissociated charge \documentclass[12pt]{minimal}\begin{document}$\bar{\alpha }$\end{document}α¯ inside the dendrimer serves as a useful parameter to map the effects of different parametric conditions and models onto each other. We also present comparisons to the scaling results proposed to explain the behavior of polyelectrolyte dendrimers. Inspired by the trends indicated by our results, we develop a strong segregation theory model whose predictions are shown to be in very good agreement with the numerical SCFT calculations.
Electronic transitions of cobalt monoboride
Authors: Ng Y. W. , Pang H. F. , Cheung A. S.-C.
Published: December 2011

Electronic transition spectrum of cobalt monoboride (CoB) in the visible region between 495 and 560 nm has been observed and analyzed using laser-induced fluorescence spectroscopy. CoB molecule was produced by the reaction of laser-ablated cobalt atom and diborane (B2H6) seeded in argon. Fifteen vibrational bands with resolved rotational structure have been recorded, which included transitions of both Co10B and Co11B isotopic species. Our analysis showed that the observed transition bands are ΔΩ = 0 transitions with Ω″ = 2 and Ω″ = 3 lower states. Four transition systems have been assigned, namely, the [18.1]3Π2–X3Δ2, the [18.3]3Φ3–X3Δ3, the [18.6]3– X3Δ3, and the [19.0]2–X3Δ2 systems. The bond length, ro, of the X 3Δ3 state of CoB is determined to be 1.705 Å. The observed rotational lines showed unresolved hyperfine structure arising from the nuclei, which conforms to the Hund's case (aβ) coupling scheme. This work represents the first experimental investigation of the CoB spectrum.
Multifrequency impedance measurement technique for wireless characterization of microbiological cell cultures
Authors: Wissenwasser J. , Vellekoop M. J. , Kapferer W. , Lepperdinger G. , Heer R.
Published: December 2011

An impedance measurement system with probe signal frequencies up to 50 kHz with AC-probe voltages below 30 mV rms was integrated for wireless and battery-free monitoring of microbiological cell cultures. The here presented modular design and the use of state-of-the-art components greatly eases adoptions to a wide range of biotechnological applications without the need of bulky LCR-meters or potentiostats. The device had a power consumption of less than 2.5 mA at a 3.3 V single power supply and worked trouble-free within the humid environment of a cell culture incubator. Measurements on lumped RC-elements showed an error of less than 1% for absolute values and less than 1° regarding the phase of the complex impedance. The performance of sensor devices with interdigitated electrode structures for the measurement of adherent cell cultures was tested in the presence of phosphate-buffered saline solution in the humid atmosphere of an incubator for biological cell cultures.
Milliwatt-level output power in the sub-terahertz range generated by photomixing in a GaAs photoconductor
Authors: Peytavit E. , Lepilliet S. , Hindle F. , Coinon C. , Akalin T. , Ducournau G. , Mouret G. , Lampin J.-F.
Published: December 2011

It is shown from accurate on-wafer measurement that continuous wave output powers of 1.2 mW at 50 GHz and 0.35 mW at 305 GHz can be generated by photomixing in a low temperature grown GaAs photoconductor using a metallic mirror Fabry-Pérot cavity. The output power is improved by a factor of about 100 as compared to the previous works on GaAs photomixers. A satisfactory agreement between the theory and the experiment is obtained in considering both the contribution of the holes and the electrons to the total photocurrent.
Role of oxygen in the OFF-state degradation of AlGaN/GaN high electron mobility transistors
Authors: Gao Feng , Lu Bin , Li Libing , Kaun Stephen , Speck James S. , Thompson Carl. V. , Palacios Tomás
Published: December 2011

The physical degradation of AlGaN/GaN high electron mobility transistors during OFF-state stress experiments has been systematically studied. Oxide particles and stringers were found to form along the gate edge of stressed devices. When the gate electrode is removed, pits are seen to have formed underneath each particle. The observed room-temperature oxidation process is strongly dependent on the duration of the electrical stressing and the electric field. Moreover, the oxidation can be significantly reduced in vacuum (3 × 10−5 Torr), with a corresponding 30% reduction of current collapse. Finally, a degradation process with electric-field-driven oxidation of the AlGaN surface has been proposed.
Anisotropic effect of piezoelectric polarization on Schottky barrier height in elastically deformed bulk GaN crystal
Authors: Fujikane Masaki , Yokogawa Toshiya , Nagao Shijo , Nowak Roman
Published: December 2011

We studied electrical characteristics in c-pane (0001) and m-plane (10−10) GaN by nanoindentation examination with a conductive diamond indenter. At constant voltage during partial indentation, the current density increased stepwise as the loading–unloading cycle went by in c-plane GaN and was constant in m-plane GaN. During several constant-indentation loads, the turn-on voltage decreased with increasing indentation load in c-plane GaN and was constant in m-plane GaN. We investigated the piezoelectric polarization anisotropy by in situ electric measurement while controlling strain in GaN crystals.
Nobel Prize in Chemistry honors the discovery of quasicrystals
Authors: Smart Ashley G.
Published: December 2011

The realization that ordered solids needn’t be translationally periodic sent experts scrambling to rewrite the textbooks on condensed matter.
”Faked states” mimic quantum entanglement
Authors: Miller Johanna L.
Published: December 2011

Bell’s inequalities are the quintessential test of the quantum nature of a system. But experiments show that the test can be fooled—if one ignores the fine print.
Texas cuts “low-producing” physics programs
Authors: Matthews Jermey N. A.
Published: December 2011

A coalition of affected institutions is preparing a proposal that could allow them to continue recruiting students and teaching advanced courses.
The curious aftermath of Neptune’s discovery
Authors: Kent Deborah
Published: December 2011

Controversy following the announcement of the new planet propelled US astronomers to the international limelight.
Wildfire activity in rainforests in western Patagonia linked to the Southern Annular Mode
Authors: Holz Andrés , Veblen Thomas T.
Published: December 2011

Increased wildfire activity in relation to future climate warming is likely for temperate rainforest biomes where fire depends on anomalously dry fuel conditions. Tree-ring fire history records were developed from fires scars in western Patagonia, and synchrony in fire activity was examined to determine the role of regional climate variability in promoting fires. Interannual variability in the multicentury fire history records was related to El Niño–Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO) and the Southern Annular Mode (SAM). Interannual fire synchrony and decadal-scale trends in wildfires document a strong influence of broad-scale climatic variability on wildfires in western Patagonia. SAM is above average during years of regional drought that coincide with widespread fires. Analyses of contingent interactions of ENSO, PDO and SAM revealed that fire frequencies were greater than expected only when SAM was in its positive phase, regardless of the phase of ENSO and PDO. The fire-enhancing influence of SAM was greatest when PDO was also positive, which indicates Pacific-wide warmer conditions. There is a strong increase in wildfire activity coincident with warming and drying trends during the 20th century and with variability in SAM, which is predicted to continue to be in this fire-conducive phase for the 21st century.
Impact of crop cycle on movement patterns of pest rodent species between fields and houses in Africa
Authors: Monadjem Ara , Mahlaba Themb'a A. , Dlamini Nomfundo , Eiseb Seth J. , Belmain Steven R. , Mulungu Loth S. , Massawe Apia W. , Makundi Rhodes H. , Mohr Katrine , Taylor Peter J.
Published: December 2011

Context Rodent pests can have severe impacts on crop production in sub-Saharan Africa. In particular, the multimammate mouse Mastomys natalensis severely damages agricultural crops in southern and eastern Africa, leading to significant losses. Both its population ecology and breeding biology have been studied in agricultural and natural habitats. Population numbers erupt depending on the timing and amount of rainfall and may reach plague proportions, especially in agricultural settings, where it may become a serious pest. However, the ecology of this species, in particular its interactions with other species within the context of human settlement, is poorly understood. It may occasionally enter houses, but the degree to which it does so and the factors influencing this movement are not known. Aims We investigated the relationship between Rattus spp. and M. natalensis entering buildings in an agro-ecological setting. We predicted that M. natalensis would enter houses more readily when food availability was lowest in the surrounding fields, and when the larger Rattus spp. were absent. Methods We followed 40 individuals of M. natalensis in Swaziland and Namibia by radio-telemetry. Mice were captured in maize fields within 50 m of a homestead and fitted with radio-transmitters at three different times corresponding to different stages of crop development: pre-harvest, post-harvest and pre-planting. To corroborate the findings of the telemetry study, a non-toxic marker, rhodamine B, was mixed with standard bait and left at bait stations inside houses in 10 homesteads in Swaziland and Tanzania. Key results Mice remained in the fields during the entire period of study in Swaziland, but entered buildings in Namibia during the post-harvest stage, which may represent a period of food shortage for these mice in the field. Rodents captured after baiting with rhodamine B demonstrated that Rattus spp. predominated within the houses. A small number of rhodamine B-marked M. natalensis were captured outside the houses, the proportion declining with distance away from the houses. Conclusions These results suggest that in a typical rural African setting dominated by subsistence agriculture, Rattus spp. (when present) competitively exclude the smaller M. natalensis from entering houses. Implications Interactions between rodent pest species may be important in determining which rodent species enter houses in rural African landscapes. Consideration of such interactions may play an important role when developing pest management strategies.
Can media campaign messages influence change towards ecologically based rodent management?
Authors: Flor Rica Joy B. , Singleton Grant R.
Published: December 2011

Context In Asia, losses to rodents contribute to the undernourishment of smallholder families. Ecologically based rodent management (EBRM) has become the national policy for rodent management in rice-based agriculture in Indonesia, the Philippines and Vietnam. EBRM requires community action. Therefore we need to develop communication campaigns that increase community involvement in rodent management. Aims This study evaluates the effects of a campaign to promote EBRM in a community that suffers chronic rodent losses to their rice crop. We hypothesised that the campaign would create changes in rodent management by farmers based on key messages delivered. Methods We documented existing beliefs and management practices, and captured changes in knowledge, attitudes and behaviour of smallholder farmers after the campaign. We also document benefits to the community. We used qualitative tools to evaluate existing beliefs and management practices of rodents in nine villages in Zaragosa, one of which was a focus village for the campaign. Key results Farmers who were influenced by the campaign had significantly higher mean rank scores in knowledge and attitudes pertaining to key messages of the campaign, such as working together, proper timing of management actions, and that rodents can be controlled. Farmers who heard the campaign obtained yields that were higher by 0.7 t ha–1 compared with those with no exposure to the campaign. A year after the campaign, the increase in rice yield in Zaragosa was sufficient to feed 1375 adult Filipinos for a year. The campaign influenced policy on rodent management in Zaragosa and subsequently at the provincial level. Conclusions A media campaign with support from local leaders and extension staff is an effective way to disseminate EBRM, leading to positive economic benefits for smallholder farmers. A media campaign alone is less effective. Implications A communication campaign on EBRM with follow-up support from extension experts is a highly effective pathway for changing attitudes and practices of smallholder farmers on rodent management, and for effective dissemination of EBRM.
Affordance and ability
Authors: Marandin Jean-Marie
Published: December 2011

This paper addresses epistemological issues raised by the use of elicited data in linguistic analyses. A common suspicion raised by experimental settings is this: participants in the lab do not replicate their everyday use of language, due to the artificiality of the tasks and of the contexts involved, so that elicited speech should not constitute a reliable source of data. I set out the experimental settings and results of four empirical studies – two studies investigating the pragmatic value of prosodic focalization through the controversial use of elicited data, one study on dative alternations based on a corpus and on a rating task, and one study on the contextual determinants of intonational contours based on a production task – to dispel this methodological suspicion: the artificiality of elicitation protocols does not prevent participants from using language as they do in spontaneous interactions. Careful examination reveals that the biases observed in the first two studies arise because subjects are not provided with sufficient cues concerning the context. I borrow the Gibsonian notion of affordance to characterise the state in which a context provides optimal resources to enable the production of the targeted construction, and argue that elicited data are reliable only when contexts optimise affordances.
Metaphor: For adults only?
Authors: Pouscoulous Nausicaa
Published: December 2011

Many experimental studies from the 70s and 80s show that children do not understand metaphors until fairly late in development (not until adolescence, some claim). I will argue that children’s metaphorical abilities may not be as weak as they first appear. Findings suggesting a poor comprehension of metaphor by young children might be better explained by factors other than purportedly inadequate pragmatic abilities. Furthermore, attested cases of metaphor production by children have often been re-analysed either as cases of overextension (i.e., erroneous extension of the term’s conventional denotation) or as cases of pretence, and are thus not considered to be genuine metaphors. I would like to explore the hypothesis that such re-analyses do not preclude the possibility that young children possess the necessary abilities to produce metaphors. Instead, some aspects of overextension and pretence may pave the way to metaphorical abilities.
Adjectival vs. nominal categorization processes
Authors: Sassoon Galit W.
Published: December 2011

Classification of entities into categories can be determined based on a rule – a single criterion or relatively few criteria combined with logical operations like ‘and’ or ‘or’. Alternatively, classification can be based on similarity to prototypical examples, i.e. an overall degree of match to prototypical values on multiple dimensions. Two cognitive systems are reported in the literature to underlie processing by rules vs. similarity. This paper presents a novel thesis according to which adjectives and nouns trigger processing by the rule vs. similarity systems, respectively. The paper defends the thesis that nouns are conceptually gradable and multidimensional, but, unlike adjectives, their dimensions are integrated through similarity operations, like weighted sums, to yield an overall degree of match to ideal values on multiple dimensions. By contrast, adjectives are associated with single dimensions, or several dimensions bound by logical operations, such as ‘and’ and ‘or’. In accordance, nouns are predicted to differ from adjectives semantically, developmentally, and processing-wise. Similarity-based dimension integration is implicit – processing is automatic, fast, and beyond speaker awareness – whereas logical, rule-based dimension integration is explicit, and is acquired late. The paper highlights a number of links between findings reported in the literature about rule- vs. similarity-based categorization and corresponding structural, distributional, neural and developmental findings about adjectives and nouns. These links suggest that the rule vs. similarity (RS) hypothesis for the adjective-noun distinction should be studied more directly in the future.
Thematising multilingualism in the media
Authors: Kelly-Holmes Helen , Milani Tommaso M.
Published: December 2011

The focus of this special issue is on the opportunities presented and challenges posed by the thematisation of multilingualism in the media. A number of case studies from a variety of linguistic, media, political, social, economic and educational contexts are presented, with the objective of addressing the challenges and opportunities that arise when multilingualism becomes thematised. In this introduction, we would like to address two main theoretical and methodological issues: (1) what we mean bymultilingualism; and, (2) what we mean bythematising.
Spanish diphthongizing stems
Authors: Carlson Matthew T. , Gerfen Chip
Published: December 2011

We examine a classic problem in Spanish morphophonology as a way of shedding new light on the relationship between grammar and processing. Spanish derivations with diphthongizing stems may contain either the diphthong or the monophthong stem allomorph, but the likelihood of the (phonotactically marked) diphthong appearing is related to the productivity of the suffix. Prior data also indicate that this bias constrains the formal properties of possible, but as yet unattested derivations. Interestingly, the documented relevance of suffix productivity and stem phonotactics for lexical processing suggests a relationship between the processing characteristics of neologisms and their favored formal properties. Spanish diphthongization provides an ideal window on this relationship because the availability of either allomorph for any neologism allows us to compare the processing characteristics of the grammatically preferred and the dispreferred form. We present visual lexical decision results that confirm the systematic biases concerning Spanish diphthongization and shed light on their possible roots in processing. The results illuminate this long-standing conundrum in Spanish and point to a more general picture in which the impact of distributional properties of morphemes on processing can account for the current shape and dynamic evolution of the lexicon.
Structural characteristics of Mg-doped (1-x)(K0.5Na0.5)NbO3–xLiSbO3 lead-free ceramics as revealed by Raman spectroscopy
Authors: Zhu W L , Zhu J L , Meng Y , Wang M S , Zhu B , Zhu X H , Zhu J G , Xiao D Q , Pezzotti G
Published: December 2011

This paper presents a Raman spectroscopic study of compositional-change-induced structure variation and of the related mechanism of Mg doping in LiSbO3 (LS)-modified (K0.5Na0.5)NbO3 (KNN) ceramics. With increasing LS content from 0 to 0.06, a discontinuous shift towards higher wavenumbers was found for the band position of the A1g(v
1) stretching mode of KNN, accompanied by a clearly nonlinear broadening of this band and a decrease in its intensity. Such morphological changes in the Raman spectrum result from two factors: (i) changes in polarizability/binding strength of the O–Nb–O vibration upon incorporation of Li ions in the KNN perovskitic structure and (ii) a polymorphic phase transition (PPT) from orthorhombic to tetragonal (O → T) phase at x > 0.04. Upon increasing the amount, w, of Mg dopant incorporated into the (1-x)KNN–xLS ceramic structure, the intensity of the Raman bands are enhanced, while the peak position and the full width at half maximum of the A1g(v
1) mode was found to experience a clear dependence on both w and x. Raman characterization revealed that the mechanism of Mg doping is strongly correlated with the concentration of Li in the perovskite structure: Mg2+ ions will preferentially replace Li+ ions for low Mg doping while replace K/Na ions for higher doping of Mg. The PPT O → T was also found to be altered by the introduction of Mg and the critical value of LS concentration, x
O−T, for incipient O → T transition in the KNN–xLS–wMT system was strongly dependent on Mg content, with x
O → T being roughly equal to 0.04 + 2w, for the case of dilute Mg alloying.
Effect of Glutamate and Blood Glutamate Scavengers Oxaloacetate and Pyruvate on Neurological Outcome and Pathohistology of the Hippocampus after Traumatic Brain Injury in Rats
Authors: Zlotnik Alexander , Sinelnikov Igor , Gruenbaum Benjamin F. , Gruenbaum Shaun E. , Dubilet Michael , Dubilet Elena , Leibowitz Akiva , Ohayon Sharon , Regev Adi , Boyko Matthew , Shapira Yoram , Teichberg Vivian I.
Published: December 2011

Background

Decreasing blood glutamate concentrations after traumatic brain injury accelerates brain-to-blood glutamate efflux, leading to improved neurologic outcomes. The authors hypothesize that treatment with blood glutamate scavengers should reduce neuronal cell loss, whereas administration of glutamate should worsen outcomes. The authors performed histologic studies of neuronal survival in the rat hippocampus after traumatic brain injury and treatment with blood glutamate scavengers.

Methods

Traumatic brain injury was induced on anesthetized male Sprague-Dawley rats by a standardized weight drop. Intravenous treatment groups included saline (control), oxaloacetate, pyruvate, and glutamate. Neurologic outcome was assessed using a Neurological Severity Score at 1 h, and 1, 2, 7, 14, 21, 28 days. Blood glutamate was determined at baseline and 90 min. Four weeks after traumatic brain injury, a histologic analysis of surviving neurons was performed.

Results

Oxaloacetate and pyruvate treatment groups demonstrated increased neuronal survival (oxaloacetate 2,200 ± 37, pyruvate 2,108 ± 137 vs. control 1,978 ± 46, P < 0.001, mean ± SD). Glutamate treatment revealed decreased neuronal survival (1,715 ± 48, P < 0.001). Treatment groups demonstrated favorable neurologic outcomes at 24 and 48 h (Neurological Severity Score at 24 and 48 h: 5.5 (1-8.25), 5 (1.75-7.25), P = 0.02 and 3(1-6.5), 4 (1.75-4.5), P = 0.027, median ± corresponding interquartile range). Blood glutamate concentrations were decreased in the oxaloacetate and pyruvate treatment groups. Administration of oxaloacetate and pyruvate was not shown to have any adverse effects.

Conclusions

The authors demonstrate that the blood glutamate scavengers oxaloacetate and pyruvate provide neuroprotection after traumatic brain injury, expressed both by reduced neuronal loss in the hippocampus and improved neurologic outcomes. The findings of this study may bring about new therapeutic possibilities in a variety of clinical settings.
Evolutionary significance of metabolic network properties
Authors: Basler Georg , Grimbs Sergio , Ebenhöh Oliver , Selbig Joachim , Nikoloski Zoran
Published: December 2011

Complex networks have been successfully employed to represent different levels of biological systems, ranging from gene regulation to protein–protein interactions and metabolism. Network-based research has mainly focused on identifying unifying structural properties, such as small average path length, large clustering coefficient, heavy-tail degree distribution and hierarchical organization, viewed as requirements for efficient and robust system architectures. However, for biological networks, it is unclear to what extent these properties reflect the evolutionary history of the represented systems. Here, we show that the salient structural properties of six metabolic networks from all kingdoms of life may be inherently related to the evolution and functional organization of metabolism by employing network randomization under mass balance constraints. Contrary to the results from the common Markov-chain switching algorithm, our findings suggest the evolutionary importance of the small-world hypothesis as a fundamental design principle of complex networks. The approach may help us to determine the biologically meaningful properties that result from evolutionary pressure imposed on metabolism, such as the global impact of local reaction knockouts. Moreover, the approach can be applied to test to what extent novel structural properties can be used to draw biologically meaningful hypothesis or predictions from structure alone.
Electromechanical phase transition in dielectric elastomers
Authors: Huang Rui , Suo Zhigang
Published: December 2011

Subject to forces and voltage, a dielectric elastomer may undergo electromechanical phase transition. A phase diagram is constructed for an ideal dielectric elastomer membrane under uniaxial force and voltage, reminiscent of the phase diagram for liquid–vapour transition of a pure substance. We identify a critical point for the electromechanical phase transition. Two states of deformation (thick and thin) may coexist during the phase transition, with the mismatch in lateral stretch accommodated by wrinkling of the membrane in the thin state. The processes of electromechanical phase transition under various conditions are discussed. A reversible cycle is suggested for electromechanical energy conversion using the dielectric elastomer membrane, analogous to the classical Carnot cycle for a heat engine. The amount of energy conversion, however, is limited by failure of the dielectric elastomer owing to electrical breakdown. With a particular combination of material properties, the electromechanical energy conversion can be significantly extended by taking advantage of the phase transition without electrical breakdown.
Evolutionary history of novel genes on the tammar wallaby Y chromosome: Implications for sex chromosome evolution
Authors: Murtagh Veronica J. , O'Meally Denis , Sankovic Natasha , Delbridge Margaret L. , Kuroki Yoko , Boore Jeffrey L. , Toyoda Atsushi , Jordan Kristen S. , Pask Andrew J. , Renfree Marilyn B. , Fujiyama Asao , Graves Jennifer A. Marshall , Waters Paul D.
Published: December 2011

We report here the isolation and sequencing of 10 Y-specific tammar wallaby (Macropus eugenii) BAC clones, revealing five hitherto undescribed tammar wallaby Y genes (in addition to the five genes already described) and several pseudogenes. Some genes on the wallaby Y display testis-specific expression, but most have low widespread expression. All have partners on the tammar X, along with homologs on the human X. Nonsynonymous and synonymous substitution ratios for nine of the tammar XY gene pairs indicate that they are each under purifying selection. All 10 were also identified as being on the Y in Tasmanian devil (Sarcophilus harrisii; a distantly related Australian marsupial); however, seven have been lost from the human Y. Maximum likelihood phylogenetic analyses of the wallaby YX genes, with respective homologs from other vertebrate representatives, revealed that three marsupial Y genes (HCFC1X/Y, MECP2X/Y, and HUWE1X/Y) were members of the ancestral therian pseudoautosomal region (PAR) at the time of the marsupial/eutherian split; three XY pairs (SOX3/SRY, RBMX/Y, and ATRX/Y) were isolated from each other before the marsupial/eutherian split, and the remaining three (RPL10X/Y, PHF6X/Y, and UBA1/UBE1Y) have a more complex evolutionary history. Thus, the small marsupial Y chromosome is surprisingly rich in ancient genes that are retained in at least Australian marsupials and evolved from testis–brain expressed genes on the X.
Sequence shortening in the rodent ancestor
Authors: Laurie Steve , Toll-Riera Macarena , Radó-Trilla Núria , Albà M. Mar
Published: December 2011

Insertions and deletions (indels), together with nucleotide substitutions, are major drivers of sequence evolution. An excess of deletions over insertions in genomic sequences—the so-called deletional bias—has been reported in a wide range of species, including mammals. However, this bias has not been found in the coding sequences of some mammalian species, such as human and mouse. To determine the strength of the deletional bias in mammals, and the influence of mutation and selection, we have quantified indels in both neutrally evolving noncoding sequences and protein-coding sequences, in six mammalian branches: human, macaque, ancestral primate, mouse, rat, and ancestral rodent. The results obtained with an improved algorithm for the placement of insertions in multiple alignments, Prank+F, indicate that contrary to previous results, the only mammalian branch with a strong deletional bias is the rodent ancestral branch. We estimate that such a bias has resulted in an ∼2.5% sequence loss of mammalian syntenic region in the ancestor of the mouse and rat. Further, a comparison of coding and noncoding sequences shows that negative selection is acting more strongly against mutations generating amino acid insertions than against mutations resulting in amino acid deletions. The strength of selection against indels is found to be higher in the rodent branches than in the primate branches, consistent with the larger effective population sizes of the rodents.