bluuebunny/crossref_metadata_2025 huggingface dataset:
Li‐, Sb‐ and Ta‐modified (K, Na)NbO3 nanopowder prepared via a water‐based sol–gel method
Authors: Fang Jian , Wang Xiaohui , Li Longtu
Published: January 2012

Stable Li‐, Sb‐ and Ta‐modified (K, Na)NbO3 (LTS‐KNN) sol and gel were successfully prepared via an economical water‐based sol–gel method. Simultaneous thermogravimetry and differential scanning calorimetry (TG‐DSC) and X‐ray diffraction showed that organic compounds were eliminated and a pure perovskite phase formed around 600 °C. Transmission electron microscopy showed that the LTS‐KNN particle size was in the range of 11–34 nm after decomposition at 600 °C. Moreover, high performance LTS‐KNN ceramic was successfully prepared at a low sintering temperature of 1000 °C by use of the nanopowder, and its room‐temperature d33, Kp, K and loss are 311 pC/N, 46.8%, 1545 and 0.024, respectively. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Low‐temperature photoluminescence of oxide‐covered single‐layer MoS2
Authors: Plechinger G. , Schrettenbrunner F.‐X. , Eroms J. , Weiss D. , Schüller C. , Korn T.
Published: January 2012

We present a photoluminescence study of single‐layer MoS2 flakes on SiO2 surfaces. We demonstrate that the luminescence peak position of flakes prepared from natural MoS2, which varies by up to 25 meV between individual flakes, can be homogenized by annealing in vacuum. We use HfO2 and Al2O3 layers prepared by atomic layer deposition to cover some of our flakes. In these flakes, we observe a suppression of the low‐energy luminescence peak which appears in asprepared flakes at low temperatures. We infer that this peak originates from excitons bound to surface adsorbates. We also observe different temperature‐induced shifts of the luminescence peaks for the oxide‐covered flakes. This effect stems from the different thermal expansion coefficients of the oxide layers and the MoS2 flakes. It indicates that the single‐layer MoS2 flakes strongly adhere to the oxide layers and are therefore strained. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Deutsche Arbeitsmarktregionen – Neuabgrenzung nach den Kreisgebietsreformen 2007–2011
Authors: Kosfeld Reinhold , Werner Alexander
Published: January 2012

Studies in Regional Economics require functional regions as statistical units. Regional labour markets are characterized by close commuter links in the regional labour markets and high seclusion towards other regional labour markets. From time to time a new delineation of regional labour markets is necessary, due to permanent changes in both, the economic and the commuter structure of a country. Particularly in Germany a new delineation is necessary, because in recent years reforms of the area of the German districts change the basis for the regional labour markets. Former delineations cannot be reconstructed with the new district boundaries. As a method to construct new regional labour markets in Germany we employ the factor analysis with oblique Oblimin rotation to German commuter structure. Additionally, the commuting distance is considered as a constraint, which improves the homogeneity of the regional labour markets, and within commuting distance of employment areas is limited to politically acceptable commuting distances. Hereby we delineate 141 regional labour markets in Germany.
ON SOME PEXIDER-TYPE FUNCTIONAL EQUATIONS CONNECTED WITH THE ABSOLUTE VALUE OF ADDITIVE FUNCTIONS. PART II
Authors: PRZEBIERACZ BARBARA
Published: January 2012

We investigate the Pexider-type functional equation where f, g, h are real functions defined on an abelian group G. We solve this equation under the assumptions G=ℝ and f is continuous.
New Zealand green-lipped mussels (Perna canaliculus) enhance non-haem iron absorptionin vitro
Authors: Stewart Robin J. C. , Coad Jane , Reynolds Gordon W. , Pedley Kevin C.
Published: January 2012

Fe bioavailability can be manipulated by the nutritional composition of a meal. Ascorbic acid and unidentified components of meat, fish and poultry, but particularly beef, all appear to enhance the absorption of non-haem Fe. The aim of the present study is to identify whether extracts of green-lipped mussels (GLM;Perna canaliculus) enhance non-haem Fe absorption in Caco-2 cells and to compare the effect with that of beef. Raw GLM and raw beef homogenates were digestedin vitrowith pepsin at pH 2, and pancreatin and bile salts at pH 7. Tracer55Fe was used to measure cellular Fe uptake. Ascorbic acid was used as a positive control and egg albumin, exposed to the samein vitrodigestion process, was used as a negative control. Caco-2 cell monolayers were incubated with treatments for 60 min. All values were standardised per μg of GLM, egg albumin, beef or ascorbic acid. The results showed that ascorbic acid enhanced non-haem Fe absorption to the highest degree. Beef and GLM digestates both significantly enhanced Fe absorption compared with egg albumin. In conclusion, GLM digestate significantly enhances non-haem Fe uptake in Caco-2 cells with a similar magnitude to that of beef.
Multiplicity of solutions to the weighted critical quasilinear problems
Authors: Liang Sihua , Zhang Jihui
Published: January 2012

We consider a class of critical quasilinear problems

where 0 ∈ Ω ⊂ ℝN, N ≥ 3, is a bounded domain and 1 < p < N, a < N/p, a ≤ b < a + 1, λ is a positive parameter, 0 ≤ μ < $\bar{\mu}$ ≡ ((N − p)/p − a)p, q = q*(a, b) ≡ Np/[N − pd] and d ≡ a+1 − b. Infinitely many small solutions are obtained by using a version of the symmetric Mountain Pass Theorem and a variant of the concentration-compactness principle. We deal with a problem that extends some results involving singularities not only in the nonlinearities but also in the operator.
Foraging behaviour and diet selection of free-ranging sheep and goats in the Negev Desert, Israel
Authors: KAM M. , EL-MECCAWI S. , DEGEN A. A.
Published: January 2012

The foraging behaviour and dietary selection of free-ranging Awassi sheep and Negev goats when shepherded in the Negev Desert was determined. Measurements were made for 9 weeks (W1–W9) from the beginning of February, following winter rains and emergence of annual plants, to the end of March, after the herbaceous vegetation dried up. Since sheep are grazers and goats are intermediate feeders, it was predicted that goats would browse more and consume proportionately more browse than sheep. These predictions were only partially supported. In fact, the foraging pattern was similar between sheep and goats (Mantel test, P<0·05) until W8 and only towards the end, at W9, did patterns differ significantly (Mantel test, P=0·214) between these two ruminants. There was no difference (P=0·575) between sheep and goats in foraging; however, a period effect was found (P<0·001). In February (W2), sheep and goats grazed 0·69 and 0·71 of the time allotted for foraging and neither species browsed. Browsing commenced only at the beginning of March (W4), when goats browsed 0·08 of the time and sheep 0·07 of the allotted time for foraging. The proportion of time spent browsing increased at the end of March (W9) when annuals disappeared, but the total time spent foraging decreased: goats browsed 0·29 and grazed 0·25, while sheep browsed 0·19 and grazed 0·26 of the time allotted for foraging. Goats increased the proportion of browse consumed gradually throughout the season, whereas sheep maintained a relatively higher proportion of herbaceous plants and only in late March (W8), at which time very little herbaceous plants were available, shifted abruptly to consume mainly browse. In W8, browse composed 0·85 of the dry matter (DM) intake in goats and 0·62 of the DM intake in sheep. A simultaneous analysis of foraging time allocation and relative diet composition revealed that both small ruminants were more efficient in consuming browse than herbaceous plants, more so in goats than sheep. It was concluded that vegetation availability and foraging habits affected dietary selection. Both sheep and goats only grazed when herbaceous plants were abundantly available; differences between ruminant species were apparent when herbaceous plants became scarcer, at which time goats browsed more and consumed proportionately more browse than sheep. The results contribute to better understanding of feeding behaviour and dietary selection of sheep and goats under natural desert pastures and could be useful in the management of mixed flocks.
The absent piece of skin: Gendered, racialized and territorial inscriptions of sexual violence during the Bangladesh war
Authors: MOOKHERJEE NAYANIKA
Published: January 2012

This paper addresses how the wombs of women and the absent skin on the circumcised penises of men become the predominant sites on which racialized and gendered discourses operating during the Bangladesh War are inscribed. This is explored by examining instances of sexual violence by Pakistani soldiers and their local Bengali collaborators. The prevalence of these discourses in colonial documents about the Bengali Muslims underscores the role of history, the politics of identity and in the process, establishes its link with the rapes of Bangladeshi women and men. Through this, the relationship between sexual violence and historical contexts is highlighted. I locate the accounts of male violations by the West Pakistani army within the historical and colonial discourses relating to the construction of the Bengali Muslim and its intertextual, contemporary citational references in photographs and interviews.

I draw on Judith Butler's and Marilyn Strathern's work on gendering and performativity to address the citational role of various practices of discourses of gender and race within colonial documents and its application in a newer context of colonization and sexual violence of women and men during wars. The role of photographs and image-making is intrinsic to these practices. The open semiotic of the photographs allows an exploration of the territorial identities within these images and leads to traces of the silence relating to male violations. Through an examination of the silence surrounding male sexual violencevis-à-visthe emphasis on the rape of women in independent Bangladesh, it is argued that these racialized and gendered discourses are intricately associated to the link between sexuality and the state in relation to masculinity.
Morphological, biological and molecular characterization of three strains ofTrypanosoma cruziChagas, 1909 (Kinetoplastida, Trypanosomatidae) isolated fromTriatoma sordida(Stal) 1859 (Hemiptera, Reduviidae) and a domestic cat
Authors: RIMOLDI ALINE , TOMÉ ALVES RENATA , AMBRÓSIO DANIELA LUZ , FERNANDES MARIA ZENAIDE TITA , MARTINEZ ISABEL , DE ARAÚJO RENATO FREITAS , CICARELLI REGINA MARIA BARRETO , DA ROSA JOÃO ARISTEU
Published: January 2012

A study was conducted of the biological, morphological and molecular characters of 3 strains ofTrypanosoma cruzi(SI5, SI8and SIGR3) isolated from specimens ofTriatoma sordidacollected in Santo Inácio and a domestic cat. In order to carry out the study, the following parameters were evaluated: pre-patent period, parasitaemia curves, morphology of the parasites, mortality rates, histopathological lesions and molecular typing. The strains presented variable pre-patent periods, low parasitaemia and no animal mortality. The morphological study of trypomastigotes showed a predominance of intermediate-width and short-length forms, as well as low nuclear index. Epimastigotes presented a low nuclear index, intermediate-width forms in strains SI5and SI8, and large-width forms in SIGR3. A shorter length could be noted in strains SI8and SIGR3, whereas SI5displayed an intermediate length. The histopathological study did not detect amastigote nests in tissues. The amplification of the divergent domain of 24SαrRNA, HSP60 and GPI genes of strains SI5, SI8and SIGR3classified the 3 strains into Group II. Biological parameters made it possible to classify the strains isolated in Santo Inácio (BA) into Biodeme III, Zymodeme 1 and Group II ofT. cruzi.
Effectiveness of water treatment for the removal ofCryptosporidiumandGiardiaspp.
Authors: BAJER A. , TOCZYLOWSKA B. , BEDNARSKA M. , SINSKI E.
Published: January 2012

CryptosporidiumandGiardiaare intestinal parasites of humans and of many other species of animals. Water constitutes an important route of transmission for human infections in both developed and developing countries. In Poland, contamination of water sources with oocysts/cysts is not routinely monitored and scientific research in this field is scarce. Our aim was to compare the contamination of surface and treated water and thus the success of water treatment processes. Water samples (n=94) of between 30 l (surface water) to over 1000 l for tap water, were taken in the period of 2008–2009 using specially constructed equipment with cartridge filtration (Filta-Max; IDEXX, USA). Immunofluorescent assay, and nested polymerase chain reaction were used for the detection of parasites.Cryptosporidiumoocysts were found in 85% of surface water and in 59% of raw (intake) water samples. Oocysts were also detected in treated water (16%) but were absent in samples of swimming pool water. The highest mean number ofCryptosporidiumoocysts [geometric mean (GM)=61/10 l] was found in samples of rinsing water.Giardiacysts were observed in 61% of surface water samples, in 6% of raw water and in 19% of treated water, with the highest number of cysts noted in rinsing water samples (GM=70 cysts/10 l). Our study highlights the frequent occurrence of parasites in surface waters in Poland and the effectiveness of water treatment for the removal of parasites from drinking water.
Raman analysis of blue ice tephra: an approach to tephrachronological dating of ice cores
Authors: Barletta Robert E.
Published: January 2012

Tephra in glacial ice provide a method to obtain a depth vs chronology correlation within an ice core. Currently, core sections containing particulate must be sacrificially analysed to determine the nature of the particulate (e.g. aerosol, micrometeor, volcanic ash), and, in the case of volcanic ash, the event tied to the particle. Characterization through melting and chemical analysis precludes, de facto, its use for other purposes. A non-destructive technique to characterize particulates in ice cores prior to sectioning the samples, e.g. optical interrogation, would be useful, especially if chemical information specific to particular volcanic eruptions could be gleaned from such an analysis. We investigated the use of micro-Raman spectroscopy for this purpose. Spectra were obtained on samples of Antarctic blue ice tephra from different sources along with a reference ash sample of New Mexico Bandelier Tuff. Vitreous and crystalline particles in the samples were characterized. For vitreous material, a detailed analysis of the Raman-active vibrational bands of the glass structure was found to have the potential of being a unique identifier of the source of the glass, however, additional library development is needed for implementation.
Developing a visual temporal modeller: applying an extensible nlp system to support learners’ understanding of tense and aspect in English
Authors: Kerins John , Ramsay Allan
Published: January 2012

This paper reports on the development of a prototype tool which shows how learners can be helped to reflect upon the accuracy of their writing. Analysis of samples of freely written texts by intermediate and advanced learners of English as a foreign language (EFL) showed evidence of weakness in the use of tense and aspect. Computational discourse modelling techniques were applied to the data to generate semantic models of fragments of the narratives with particular focus on their temporal structure. These models have been converted into dynamic graphical representations of the temporal relationships between discourse events as the narratives are written. The system also provides access to the ontology devised to model individual events and this offers learners insights into the events’ semantic properties. These techniques provide the basis for a stimulating learning tool capable of capturing key elements of written narratives, and prompting learners’ awareness of language use, particularly tense and aspect.
Reforming the Presidential Primary System: The Voter Turnout Initiative
Authors: Frederick Heather
Published: January 2012

This article examines the presidential nomination process and proposes reform that includes shortening the primary calendar and ordering the states by voter turnout in the previous presidential general election.
APSA Executive Director's Report, 2011
Authors: Brintnall Michael
Published: January 2012

The annual executive director's report documents APSA's activities and directions for the year. The traditional core activities for a learned society are its journals and conferences. APSA, like its counterparts, also supports the discipline and the professional interests of members in a variety of ways: support for department chairs and academic programs, engagement with federal policymaking on support for scholarship and education, and attention to the pipeline of prospective new scholars in the discipline. Some of these initiatives focus on resources for individual political scientists, such as our mentoring initiative, and many are built around management of the commons of the discipline and efforts to assure that we collectively address matters that affect the discipline. APSA is active on many of these fronts, and this report in particular highlights those APSA activities that help support the disciplinary community as a whole.
APSA's Financial Operations 2010–2011
Authors: Lupia Arthur , Chavis Regina
Published: January 2012

The purpose of this report is to inform APSA's membership about the association's financial health. This report provides an overview of APSA's assets and current financial operations.
Defensa – Tesoro II. A Medley of Filmed Sequences from the Performance
Authors: Ingemarsson Eva
Published: January 2012

At http://www.evaingemarsson.se/verk/defensa you will find a medley of scenes from Eve Ingemarsson's performance Defensa – Tesoro II, which was included in the seminar programme.
Cognitive Behavioural Therapy for Japanese Children and Adolescents with Anxiety Disorders: A Pilot Study
Authors: Ishikawa Shin-ichi , Motomura Naoyasu , Kawabata Yasuo , Tanaka Hidetaka , Shimotsu Sakie , Sato Yoko , Ollendick Thomas H.
Published: January 2012

Background: Thirty-three Japanese children and adolescents diagnosed with an anxiety disorder participated in individual or group Cognitive Behaviour Therapy (CBT) that was modelled after evidence-based intervention programs developed in Western countries. Method: The treatment consisted of: (a) building rapport and education; (b) identifying emotions and recognizing cognitive self-talk; (c) challenging anxious self-talk; (d) developing an anxiety hierarchy and in vivo exposures; and (e) planning for future challenges. Results: Three months following treatment, 20 of the 33 children and adolescents (60.91%) no longer met criteria for their principal anxiety disorders and 16 (48.48%) were free from all anxiety disorders. Self-reported anxiety, depression, and cognitive errors also decreased significantly from pre- to post-treatment and these gains were maintained at 3-month follow-up. For the most part, similar outcomes were found in both the group and individual formats of CBT. Conclusions: This study provides preliminary support for the transportability of CBT in both an individual and group format to Japan.
Priming of code-switches in sentences: The role of lexical repetition, cognates, and language proficiency
Authors: KOOTSTRA GERRIT JAN , VAN HELL JANET G. , DIJKSTRA TON
Published: January 2012

In two experiments, we tested the role of lexical repetition, cognates, and second language (L2) proficiency in the priming of code-switches, using the structural priming technique. Dutch–English bilinguals repeated a code-switched prime sentence (starting in Dutch and ending in English) and then described a target picture by means of a code-switched sentence (also from Dutch into English). Low- and high-proficient speakers of L2 English were tested in Experiments 1 and 2, respectively. We found that the participants’ tendency to switch at the same position as in the prime sentence was influenced by lexical repetition between prime sentence and target picture and by the presence of a cognate in prime and target. A combined analysis showed that these lexical effects were stronger in the high-proficient than in the low-proficient L2 speakers. These results provide new insights into how language-related and speaker-related variables influence code-switching in sentences, and extend cognitive models of lexical and combinatorial processes in bilingual sentence production.
Dye Surface Coating Enables Visible Light Activation of TiO2 Nanoparticles Leading to Degradation of Neighboring Biological Structures
Authors: Blatnik Jay , Luebke Lanette , Simonet Stephanie , Nelson Megan , Price Race , Leek Rachael , Zeng Leyong , Wu Aiguo , Brown Eric
Published: January 2012

Biologically and chemically modified nanoparticles are gaining much attention as a new tool in cancer detection and treatment. Herein, we demonstrate that an alizarin red S (ARS) dye coating on TiO2 nanoparticles enables visible light activation of the nanoparticles leading to degradation of neighboring biological structures through localized production of reactive oxygen species. Successful coating of nanoparticles with dye is demonstrated through sedimentation, spectrophotometry, and gel electrophoresis techniques. Using gel electrophoresis, we demonstrate that visible light activation of dye-TiO2 nanoparticles leads to degradation of plasmid DNA in vitro. Alterations in integrity and distribution of nuclear membrane associated proteins were detected via fluorescence confocal microscopy in HeLa cells exposed to perinuclear localized ARS-TiO2 nanoparticles that were photoactivated with visible light. This study expands upon previous studies that indicated dye coatings on TiO2 nanoparticles can serve to enhance imaging, by clearly showing that dye coatings on TiO2 nanoparticles can also enhance the photoreactivity of TiO2 nanoparticles by allowing visible light activation. The findings of our study suggest a therapeutic application of dye-coated TiO2 nanoparticles in cancer research; however, at the same time they may reveal limitations on the use of dye assisted visualization of TiO2 nanoparticles in live-cell imaging.
Characterization of Nanometer-Scale Porosity in Reservoir Carbonate Rock by Focused Ion Beam–Scanning Electron Microscopy
Authors: Bera Bijoyendra , Gunda Naga Siva Kumar , Mitra Sushanta K. , Vick Douglas
Published: January 2012

Sedimentary carbonate rocks are one of the principal porous structures in natural reservoirs of hydrocarbons such as crude oil and natural gas. Efficient hydrocarbon recovery requires an understanding of the carbonate pore structure, but the nature of sedimentary carbonate rock formation and the toughness of the material make proper analysis difficult. In this study, a novel preparation method was used on a dolomitic carbonate sample, and selected regions were then serially sectioned and imaged by focused ion beam–scanning electron microscopy. The resulting series of images were used to construct detailed three-dimensional representations of the microscopic pore spaces and analyze them quantitatively. We show for the first time the presence of nanometer-scale pores (50–300 nm) inside the solid dolomite matrix. We also show the degree of connectivity of these pores with micron-scale pores (2–5 μm) that were observed to further link with bulk pores outside the matrix.
Flow and turbulence redistribution in a straight artificial pool
Authors: MacVicar Bruce J. , Rennie Colin D.
Published: January 2012

Multiple hypotheses have been advanced to explain the occurrence of pools in gravel bed rivers. These hypotheses were developed without a hydrodynamic model of how open channel flow is affected by pools, and it is not clear why and when the flow phenomena they describe might occur. Laboratory experiments are warranted to improve our understanding of how a gradual convective deceleration and acceleration of the flow, without flow separation, redistributes flow and turbulence in an open channel. Experiments are conducted in a 1.5 m wide flume with a 0.25 m deep, 7.29 m long straight pool, entry and exit slopes of 5°, vertical side walls, and gravel sediment (D50 = 9.9 mm). Three‐dimensional velocity components are recorded at 50 Hz using Nortek Vectrinos. Velocity and Reynolds stress profiles in the channel centerline agree with previous results in nonuniform flow and include increased Reynolds stress during deceleration and high velocity near the bed during acceleration. Lateral flow convergence occurs where depth is increasing, which demonstrates that convergence is induced during flow deceleration and does not require a lateral flow constriction. Turbulence during deceleration is characterized by sweeps angled toward the sidewall of the channel, an effect that could lead to the formation of a nonuniform pool depth through lateral gradients in the deposition of mobile sediment. A conceptual model of pool hydrodynamics is proposed that includes increased turbulence, near‐bed acceleration, and lateral flow convergence as linked aspects of convective deceleration and acceleration due to depth changes in the pool.
Shear wave reflectivity imaging of the Nazca‐South America subduction zone: Stagnant slab in the mantle transition zone?
Authors: Contenti Sean , Gu Yu Jeffrey , Ökeler Ahmet , Sacchi Mauricio D.
Published: January 2012

In this study we utilize over 5000 SS waveforms to investigate the high‐resolution mantle reflectivity structure down to 1200 km beneath the South American convergent margin. Our results indicate that the dynamics of the Nazca subduction are more complex than previously suggested. The 410‐ and 660‐km seismic discontinuities beneath the Pacific Ocean and Amazonian Shield exhibit limited lateral depth variations, but their depths vary substantially in the vicinity of the subducting Nazca plate. The reflection amplitude of the 410‐km discontinuity is greatly diminished in a ∼1300‐km wide region in the back‐arc of the subducting plate, which is likely associated with a compositional heterogeneity on top of the upper mantle transition zone. The underlying 660‐km discontinuity is strongly depressed, showing localized depth and amplitude variations both within and to the east of the Wadati‐Benioff zone. The width of this anomalous zone (∼1000 km) far exceeds that of the high‐velocity slab structure and suggesting significant slab deformation within the transition zone. The shape of the 660‐km discontinuity and the presence of lower mantle reflectivity imply both stagnation and penetration are possible as the descending Nazca slab impinges upon the base of the upper mantle.
Effects of amines on formation of sub‐3 nm particles and their subsequent growth
Authors: Yu Huan , McGraw Robert , Lee Shan‐Hu
Published: January 2012

Field observations and quantum chemical calculations suggest that amines can be important for formation of nanometer size particles. Amines and ammonia often have common atmospheric emission sources and the similar chemical and physical properties. While the effects of ammonia on aerosol nucleation have been previously investigated, laboratory studies of homogeneous nucleation involving amines are lacking. We have made kinetics studies of multicomponent nucleation (MCN) with sulfuric acid, water, ammonia and amines under conditions relevant to the atmosphere. Low concentrations of aerosol precursors were measured with chemical ionization mass spectrometers (CIMS) to provide constrained precursor concentrations needed for nucleation. Particle sizes larger than ∼2 nm were measured with a nano‐differential mobility analyzer (nano‐DMA), and number concentrations of particles larger than ∼1 nm were measured with a particle size magnifier (PSM). Our observations provide the laboratory evidence that amines indeed can participate in aerosol nucleation and growth at the molecular cluster level. The enhancement of particle number concentrations due to several atmospherically relevant amine compounds and ammonia were related to the basicity of these compounds, indicating that acid–base reactions may contribute to the formation of sub‐3 nm particles.
Fundamental characteristics of field‐aligned auroral acceleration derived from AKR spectra
Authors: Morioka A. , Miyoshi Y. , Kitamura N. , Misawa H. , Tsuchiya F. , Menietti J. D. , Honary F.
Published: January 2012

This paper examines AKR spectra using the long‐term observation from the Polar satellite to prove the comprehensive features of field‐aligned auroral acceleration and to give observational constraints to the theoretical mechanisms for acceleration at substorm. The remote observations of substorm phenomena through auroral radio waves from the high altitude polar magnetosphere disclosed some fundamental characteristics of the vertical auroral acceleration region and provided new information on the formation process for field‐aligned electric field at substorm onset. Furthermore, we reveal new aspect of the relationship between the plasma state in the plasma sheet and the formation of auroral acceleration.
Slip in the 2010–2011 Canterbury earthquakes, New Zealand
Authors: Elliott J. R. , Nissen E. K. , England P. C. , Jackson J. A. , Lamb S. , Li Z. , Oehlers M. , Parsons B.
Published: January 2012

The 3rd September 2010 Mw 7.1 Darfield and 21st February 2011 Mw 6.3 Christchurch (New Zealand) earthquakes occurred on previously unknown faults. We use InSAR ground displacements, SAR amplitude offsets, field mapping, aerial photographs, satellite optical imagery, a LiDAR DEM and teleseismic body‐wave modeling to constrain the pattern of faulting in these earthquakes. The InSAR measurements reveal slip on multiple strike‐slip segments and secondary reverse faults associated with the Darfield main shock. Fault orientations are consistent with those expected from the GPS‐derived strain field. The InSAR line‐of‐sight displacement field indicates the main fault rupture is about 45 km long, and is confined largely to the upper 10 km of the crust. Slip on the individual fault segments of up to 8 m at 4 km depth indicate stress drops of 6–10 MPa. In each event, rupture initiated on a reverse fault segment, before continuing onto a strike‐slip segment. The non‐double couple seismological moment tensors for each event are matched well by the sum of double couple equivalent moment tensors for fault slip determined by InSAR. The slip distributions derived from InSAR observations of both the Darfield and Christchurch events show a 15‐km‐long gap in fault slip south‐west of Christchurch, which may present a continuing seismic hazard if a further unknown fault structure of significant size should exist there.
Lightning morphology and impulse charge moment change of high peak current negative strokes
Authors: Lu Gaopeng , Cummer Steven A. , Blakeslee Richard J. , Weiss Stephanie , Beasley William H.
Published: January 2012

We have analyzed very high frequency lightning mapping observations and remote magnetic field measurements to investigate connections between lightning morphology and impulse charge moment change (iCMC) of negative cloud‐to‐ground (CG) strokes with high estimated peak currents. Four lightning morphologies are identified for a total of 2126 strokes within optimum detection range of the North Alabama Lightning Mapping Array, and statistical iCMC distributions are given for each of these types. Almost all (>90%) of the largest impulse charge moments (greater than −200 C km in this data set) are not produced by strokes in ordinary negative CG flashes. Instead, negative strokes with the largest iCMCs are almost exclusively associated with two unusual flash types that both initially develop as positive (normal) intracloud lightning. In the first type the negative stroke with high iCMCs results from a negative leader that descends from the midlevel negative charge region after the upper level negative leader ceases propagating. In the second type, the upper level negative leader of the intracloud lightning progresses toward ground as a so‐called bolt from the blue to generate the negative stroke. Measurements of strokes associated with four negative polarity sprites suggest that all four were most likely produced in the first unusual lightning type. Our results highlight that estimated peak current and impulse charge transfer are not always well correlated and that the in‐cloud lightning structure strongly influences charge transfer on short time scales in negative CG strokes.
Seasonal composition of remote and urban fine particulate matter in the United States
Authors: Hand J. L. , Schichtel B. A. , Pitchford M. , Malm W. C. , Frank N. H.
Published: January 2012

Speciated aerosol composition data from the rural Interagency Monitoring for Protected Visual Environments (IMPROVE) network and the Environmental Protection Agency's urban/suburban Chemical Speciation Network (CSN) were combined to evaluate and contrast the PM2.5 composition and its seasonal patterns at urban and rural locations throughout the United States. We examined the 2005–2008 monthly and annual mean mass concentrations of PM2.5 ammonium sulfate (AS), ammonium nitrate (AN), particulate organic matter (POM), light‐absorbing carbon (LAC), mineral soil, and sea salt from 168 rural and 176 urban sites. Urban and rural AS concentrations and seasonality were similar, and both were substantially higher in the eastern United States. Urban POM and LAC concentrations were higher than rural concentrations and were associated with very different seasonality depending on location. The highest urban and rural POM and LAC concentrations occurred in the southeastern and northwestern United States. Wintertime peaks in AN were common for both urban and rural sites, but urban concentrations were several times higher, and both were highest in California and the Midwest. Fine soil concentrations were highest in the Southwest, and similar regional patterns and seasonality in urban and rural concentrations suggested impacts from long‐range transport. Contributions from sea salt to the PM2.5 budget were non‐negligible only at coastal sites. This analysis revealed spatial and seasonal variability in urban and rural aerosol concentrations on a continental scale and provided insights into their sources, processes, and lifetimes.
Using the deuterium isotope composition of permafrost meltwater to constrain thermokarst lake contributions to atmospheric CH4 during the last deglaciation
Authors: Brosius L. S. , Walter Anthony K. M. , Grosse G. , Chanton J. P. , Farquharson L. M. , Overduin P. P. , Meyer H.
Published: January 2012

Thermokarst lakes are thought to have been an important source of methane (CH4) during the last deglaciation when atmospheric CH4 concentrations increased rapidly. Here we demonstrate that meltwater from permafrost ice serves as an H source to CH4production in thermokarst lakes, allowing for region‐specific reconstructions ofδDCH4 emissions from Siberian and North American lakes. δDCH4 reflects regionally varying δD values of precipitation incorporated into ground ice at the time of its formation. Late Pleistocene‐aged permafrost ground ice was the dominant H source to CH4production in primary thermokarst lakes, whereas Holocene‐aged permafrost ground ice contributed H to CH4 production in later generation lakes. We found that Alaskan thermokarst lake δDCH4 was higher (−334 ± 17‰) than Siberian lake δDCH4 (−381 ± 18‰). Weighted mean δDCH4values for Beringian lakes ranged from −385‰ to −382‰ over the deglacial period. Bottom‐up estimates suggest that Beringian thermokarst lakes contributed 15 ± 4 Tg CH4 yr−1 to the atmosphere during the Younger Dryas and 25 ± 5 Tg CH4 yr−1during the Preboreal period. These estimates are supported by independent, top‐down isotope mass balance calculations based on ice coreδDCH4 and δ13CCH4 records. Both approaches suggest that thermokarst lakes and boreal wetlands together were important sources of deglacial CH4.
Necking of continental crust in magma‐poor rifted margins: Evidence from the fossil Alpine Tethys margins
Authors: Mohn G. , Manatschal G. , Beltrando M. , Masini E. , Kusznir N.
Published: January 2012

Studies conducted in present‐day magma‐poor rifted margins reveal that the transition from weakly thinned continental crust (∼30 km) in proximal margins to hyper‐extended crust (≤10 km) in distal margins occurs within a narrow zone, referred to as the necking zone. We have identified relics of a necking zone and of the adjacent distal margin in the Campo, Grosina and Bernina units of the fossil Alpine Tethys margins and investigated the deformation and sedimentary processes associated with extreme crustal thinning during rifting. Within the basement rocks of the necking zone, we show that: (1) Grosina basement represents pre‐rift upper/middle crust, while the underlying Campo unit consists of pre‐rift middle/lower crust that was exhumed and cooled below ∼300°C by ca. 180 Ma, when rifting started to localize within the future distal margin; (2) the juxtaposition of the Campo and Grosina units was accommodated by the Eita shear zone, which is interpreted as a decollement/decoupling horizon active at mid‐crustal depth at 180–205 Ma; (3) the Grosina unit hosts a large‐scale brittle detachment fault. Our observations suggest that crustal thinning, accommodated through the necking zone, is the result of the interplay between detachment faulting in the brittle layers and decoupling and thinning in ductile quartzo‐feldspatic middle crustal levels along localized ductile decollements. The excision of ductile mid‐crustal layers and the progressive embrittlement of the crust enables major detachment faults to cut into the underlying mantle, exhuming it to the seafloor. This structural evolution can explain the first‐order crustal architecture of many present‐day rifted margins.
White-Matter Astrocytes, Axonal Energy Metabolism, and Axonal Degeneration in Multiple Sclerosis
Authors: Cambron Melissa , D'Haeseleer Miguel , Laureys Guy , Clinckers Ralph , Debruyne Jan , De Keyser Jacques
Published: January 2012

In patients with multiple sclerosis (MS), a diffuse axonal degeneration occurring throughout the white matter of the central nervous system causes progressive neurologic disability. The underlying mechanism is unclear. This review describes a number of pathways by which dysfunctional astrocytes in MS might lead to axonal degeneration. White-matter astrocytes in MS show a reduced metabolism of adenosine triphosphate-generating phosphocreatine, which may impair the astrocytic sodium potassium pump and lead to a reduced sodium-dependent glutamate uptake. Astrocytes in MS white matter appear to be deficient in β2 adrenergic receptors, which are involved in stimulating glycogenolysis and suppressing inducible nitric oxide synthase (NOS2). Glutamate toxicity, reduced astrocytic glycogenolysis leading to reduced lactate and glutamine production, and enhanced nitric oxide (NO) levels may all impair axonal mitochondrial metabolism, leading to axonal degeneration. In addition, glutamate-mediated oligodendrocyte damage and impaired myelination caused by a decreased production of N-acetylaspartate by axonal mitochondria might also contribute to axonal loss. White-matter astrocytes may be considered as a potential target for neuroprotective MS therapies.
Structure–function studies of a plant tyrosyl-DNA phosphodiesterase provide novel insights into DNA repair mechanisms of Arabidopsis thaliana
Authors: Kim Hoyeun , Na Sang Hyeon , Lee So-Young , Jeong Young-Min , Hwang Hyun-Ju , Hur Jae Young , Park Sang-Hyun , Woo Je-Chang , Kim Sang-Gu
Published: January 2012

TDP1 (tyrosyl-DNA phosphodiesterase 1), a member of the PLD (phospholipase D) superfamily, catalyses the hydrolysis of a phosphodiester bond between a tyrosine residue and the 3′-phosphate of DNA. We have previously identified and characterized the AtTDP gene in Arabidopsis thaliana, an orthologue of yeast and human TDP1 genes. Sequence alignment of TDP1 orthologues revealed that AtTDP has both a conserved C-terminal TDP domain and, uniquely, an N-terminal SMAD/FHA (forkhead-associated) domain. To help understand the function of this novel enzyme, we analysed the substrate saturation kinetics of full-length AtTDP compared with a truncated AtTDP mutant lacking the N-terminal FHA domain. The recombinant AtTDP protein hydrolysed a single-stranded DNA substrate with Km and kcat/Km values of 703±137 nM and (1.5±0.04)×109M−1·min−1 respectively. The AtTDP-(Δ1–122) protein (TDP domain) showed kinetic parameters that were equivalent to those of the full-length AtTDP protein. A basic amino acid sequence (RKKVKP) within the AtTDP-(Δ123–605) protein (FHA domain) was necessary for nuclear localization of AtTDP. Analysis of active-site mutations showed that a histidine and a lysine residue in each of the HKD motifs were critical for enzyme activity. Vanadates, inhibitors of phosphoryl transfer reactions, inhibited AtTDP enzymatic activity and retarded the growth of an Arabidopsis tdp mutant. Finally, we showed that expression of the AtTDP gene could complement a yeast tdp1Δrad1Δ mutant, rescuing the growth inhibitory effects of vanadate analogues and CPT (camptothecin). Taken together, the results of the present study demonstrate the structure-based function of AtTDP through which AtTDP can repair DNA strand breaks in plants.
Electric-field-induced current-voltage characteristics in electronic conducting perovskite thin films
Authors: Rupp Jennifer L. M. , Reinhard Patrick , Pergolesi Daniele , Ryll Thomas , Tölke Rene , Traversa Enrico
Published: January 2012

Mixed ionic-electronic conductors (MIECs) such as the (La,Sr)(Co,Fe)O3−d perovskite family are well described in their charge transport through their high temperature applications, i.e., as solid-oxide fuel cell electrodes (600–1000 °C). In this study, the current-voltage (I-V) profiles of these well-known MIEC perovskites are studied between room temperature and 150 °C under bias of ±15 V for potential applications in resistance random access memories. The impact of the metal-oxide interface on the I-V characteristics ranging from ohmic to non-linear hysteretic is discussed for metals of varying work functions and redox potentials, as well as changes in metal electrode distances and areas.
Tree-shaped fluid flow and heat storage in a conducting solid
Authors: Combelles L. , Lorente S. , Anderson R. , Bejan A.
Published: January 2012

This paper documents the time-dependent thermal interaction between a fluid stream configured as a plane tree of varying complexity embedded in a conducting solid with finite volume and insulated boundaries. The time scales of the convection-conduction phenomenon are identified. Two-dimensional and three-dimensional configurations are simulated numerically. The number of length scales of the tree architecture varies from one to four. The results show that the heat transfer density increases, and the time of approach to equilibrium decreases as the complexity of the tree designs increases. These results are then formulated in the classical notation of energy storage by sensible heating, which shows that the effective number of heat transfer units increases as the complexity of the tree design increases. The complexity of heat transfer designs in many applications is constrained by first cost and operating cost considerations. This work provides a fundamental basis for objective evaluation of cost and performance tradeoffs in thermal design of energy systems with complexity as an unconstrained parameter that can be actively varied over a broad range to determine the optimum system design.
Hydrogen bonds in the nucleobase-gold complexes: Photoelectron spectroscopy and density functional calculations
Authors: Cao Guo-Jin , Xu Hong-Guang , Li Ren-Zhong , Zheng Weijun
Published: January 2012

The nucleobase-gold complexes were studied with anion photoelectron spectroscopy and density functional calculations. The vertical detachment energies of uracil-Au−, thymine-Au−, cytosine-Au−, adenine-Au−, and guanine-Au− were estimated to be 3.37 ± 0.08 eV, 3.40 ± 0.08 eV, 3.23 ± 0.08 eV, 3.28 ± 0.08 eV, and 3.43 ± 0.08 eV, respectively, based on their photoelectron spectra. The combination of photoelectron spectroscopy experiments and density functional calculations reveals the presence of two or more isomers for these nucleobase-gold complexes. The major isomers detected in the experiments probably are formed by Au anion with the canonical tautomers of the nucleobases. The gold anion essentially interacts with the nucleobases through N-H···Au hydrogen bonds.
Basis set dependence of higher-order correlation effects in π-type interactions
Authors: Carrell Emily J. , Thorne Cara M. , Tschumper Gregory S.
Published: January 2012

The basis set dependence of higher-order correlation effects on π-type interaction energies was examined by scanning the potential energy surfaces of five dimer systems. The dimers of acetylene (H−C≡C−H), diacetylene (H−C≡C−C≡C−H), cyanogen (N≡C−C≡N), diphosphorous (P≡P), and 1,4-diphosphabutadiyne (P≡C−C≡P) were studied in three different configurations: cross, parallel-displaced, and t-shaped. More than 800 potential energy curves (PECs) were generated by computing the interaction energies for all 15 dimer configurations over a range of intermolecular distances with the MP2, coupled-cluster single double (CCSD), and coupled-cluster single double triple (CCSD(T)) methods in conjunction with 21 basis sets ranging from a small 6-31G*(0.25) split-valence basis set to a large aug-cc-pVQZ correlation consistent basis set. Standard extrapolation techniques were also used to construct MP2, CCSD, and CCSD(T) complete basis set (CBS) limit PECs as well as CBS limit higher-order correlation corrections based on the differences between CCSD(T) and MP2 interaction energies, denoted \documentclass[12pt]{minimal}\begin{document}$\delta _{\mathrm{MP2}} ^{\mathrm{CCSD(T)}}$\end{document}δ MP 2 CCSD (T), and the corresponding differences between CCSD(T) and CCSD interactions energies, denoted \documentclass[12pt]{minimal}\begin{document}$\delta _{\mathrm{CCSD}}^{\mathrm{CCSD(T)}}$\end{document}δ CCSD CCSD (T). Double-ζ basis sets struggled to reproduce the former but provided quite reasonable descriptions of the latter as long as diffuse functions were included. The aug-cc-pVDZ basis deviated from the \documentclass[12pt]{minimal}\begin{document}$\delta _{\mathrm{CCSD}}^{\mathrm{CCSD(T)}}$\end{document}δ CCSD CCSD (T) CBS limit by only 0.06 kcal mol−1 on average and never by more than 0.24 kcal mol−1, whereas the corresponding deviations were approximately twice that for the \documentclass[12pt]{minimal}\begin{document}$\delta _{\mathrm{MP2}}^{\mathrm{CCSD(T)}}$\end{document}δ MP 2 CCSD (T) term. While triple-ζ basis sets typically improved results, only aug-cc-pVTZ provided appreciable improvement over utilizing the aug-cc-pVDZ basis set to compute \documentclass[12pt]{minimal}\begin{document}$\delta _{\mathrm{CCSD}}^{\mathrm{CCSD(T)}}$\end{document}δ CCSD CCSD (T). Counterpoise (CP) corrections were also applied to all double- and triple-ζ basis sets, but they rarely yielded a better description of these higher-order correlation effects. CP corrections only consistently improved results when the aug-cc-pVDZ basis set was used to compute \documentclass[12pt]{minimal}\begin{document}$\delta _{\mathrm{MP2}}^{\mathrm{CCSD(T)}}$\end{document}δ MP 2 CCSD (T), yielding mean and maximum absolute deviations from the CBS values of 0.10 and 0.39 kcal mol−1, respectively, for all five dimer systems.
On the local well posedness and blow-up solution of a coupled Camassa-Holm equations in Besov Spaces
Authors: Tian Lixin , Yan Wanfeng , Gui Guilong
Published: January 2012

In this paper, we establish the local well-posedness for a new coupled Camassa-Holm system in a range of the Besov spaces by employing a series of norm estimates. A wave-breaking mechanism for solutions is described in detail and a result of blow-up solutions with certain profile is established.