bluuebunny/crossref_metadata_2025 huggingface dataset:
Geodynamics and stress–strain patterns in different tectonic settings
Authors: Dobretsov N.L. , Koulakov I.Yu. , Polyansky O.P.
Published: March 2013

Deformation patterns in subduction zones, feeder systems of volcanoes, and rifts are compared and investigated in terms of relations among elastoplastic strain, rheology, pore fluids, and temperature. Regional-scale subduction processes have been explored in segments of the Kuriles–Kamchatka, Izu-Bonin, and Mariana zones. Slab geometry constraints from the 3D velocity structure are used to model the balance of forces in the three subduction zones and to distinguish the regions of predominant push or pull. Stress and strain variations in suprasubduction crust are considered for the case of magma sources beneath the Klyuchevskoy group of volcanoes. Time-lapse (4D) seismic tomography shows crustal magma reservoirs to appear and disappear rapidly as the volcanoes become active or dormant, respectively. This behavior is due to rapid strain changes which cause fast flow of fluids and the ensuing decrease or increase of melting temperature in the magma reservoirs. In addition to subduction zones, stress-strain patterns are modeled for collisional (compressive) settings, with the example of the Altai–Sayan area and the Caucasus, and for the conditions of rifting (extension), in the case of the Vilyui basin. As the modeling shows, formation of a superdeep basin does not necessarily require the crust to stretch twice or more: only 20% stretching in the necking region is enough to produce a 10–15 km deep basin.
Kinematic reconstruction of the Early Caledonian accretion in the southwest of the Siberian paleocontinent based on paleomagnetic results
Authors: Metelkin D.V.
Published: March 2013

The kinematics of the Early Caledonian accretion process in the southwest (in modern coordinate) of the Siberian paleocontinent, and the structure of its active continental margin are debatable subjects. This paper contains a generalization of paleomagnetic data on island-arc terranes of the territories of the Altai–Sayan and Baikal–Vitim folded areas for the Late Vendian/Cambrian–Early Ordovician time interval, obtained mostly with the author’s participation during the last two decades. The large accumulated database finally allows one to find unambiguously interpretable patterns in the distribution of paleomagnetic poles for the analyzed terrane system and to justify numerically the kinematics of the Early Caledonian accretion. In particular, the analysis of paleomagnetic data proves our idea stating that the transformation of the active continental margin in the Cambrian consisted in its breakup and segmentation as well as in the detachment of fragments of the initially whole island arc along a system of sinistral strike-slips during the clockwise rotation of the craton and conform drift of the continental and oceanic lithospheric plates. It also validates the mostly oblique conditions of the subduction and subsequent accretion, which means a subduction-transform mode on the ocean–continent margin. We propose a complemented version of the paleotectonic reconstruction for the Cambrian evolution of the Siberian continent western margin, based on the kinematic scheme constructed from paleomagnetic data.
The stability of ortho- and clinopyroxenes, olivine, and garnet in kimberlitic magma
Authors: Chepurov A.I. , Zhimulev E.I. , Agafonov L.V. , Sonin V.M. , Chepurov A.A. , Tomilenko A.A.
Published: March 2013

It is generally accepted that the composition of ultrabasic nodules and their quantitative proportions do not significantly change during their transportation with kimberlitic magma to the Earth’s surface. We performed an experimental study of the relative stability of olivine, garnet, and pyroxenes in kimberlite melt at high pressure and temperatures (4 GPa, 1300–1500 °C). The study has shown that the loss in weight of minerals and, correspondingly, the rate of their dissolution in kimberlite melt differ considerably. The following sequence of the dissolution rates of minerals has been established: Cpx ≥ Opx > Gar > Ol. Pyroxenes are characterized by the most rapid dissolution, and olivine is the most stable mineral. The assumption is made that clinopyroxenites and websterites disintegrate more rapidly than dunites and lherzolites in kimberlitic magma.
Effect of the depositional environment on the compositional variations among the phosphorite deposits in Egypt
Authors: Baioumy H.M.
Published: March 2013

Late Cretaceous economic phosphorites from the Red Sea, Nile Valley, and Abu Tartur areas, Egypt, show distinct variations in the lithology of associated sediments, mineralogy of nonphosphatic constituents, and distributions of major and trace elements. In the Red Sea area, the phosphorite beds are intercalated with laminated black shales, and the nonphosphatic constituents are detrital quartz and calcite, ankerite, and pyrite cements. In the Nile Valley, the phosphorite beds are intercalated with chert, marl, and sandstone and the nonphosphatic constituents are detrital quartz and calcite and chalcedony cements. In the Abu Tartur Plateau, the phosphorite beds are intercalated with laminated black shales, and the nonphosphatic constituents are detrital quartz and ankerite and pyrite cements. The phosphorites studied also show distinct variations in major- and trace-element concentrations. The Abu Tartur phosphorites have higher contents of TiO2, Al2O3, Fe2O3, K2O, Co, Nb, Pb, Sr, Th, Y, and Zr and lower SiO2, Ba, and U contents as compared to those in the Red Sea and Nile Valley areas. The positive correlations between Al2O3 and TiO2, K2O, Nb, Y, and Zr suggest the detrital origin of these constituents.

Similarity in the phosphatic constituents, which were derived from outside the depositional sites, and variations in the lithology of associated sediments and the mineralogy and geochemistry of the nonphosphatic constituents, which reflect the conditions at the depositional sites, suggest that the variations in the depositional environment of the phosphorites are the potential controlling factor of the compositional variations among these phosphorites. The abundance of black shales in the Red Sea and Abu Tartur areas, as well as the occurrence of ankerite and pyrite as cementing materials for the phosphatic constituents, might reflect reducing conditions in these areas, while the abundance of siliciclastic sediments and calcite and chalcedony cements suggests oxidizing conditions in the Nile Valley. The reducing conditions in the Red Sea and Abu Tartur areas were probably developed within the pre-existing depressions in a shelf environment. These depressions might have formed as a result of a change in the movements of the North Atlantic, Eurasian, and African Plates during the late Santonian, which led to transgressive inversion of rifts along northern Egypt and consequent folding in the continental interior. The higher contents of detrital components in the Abu Tartur phosphorites compared to the Red Sea and Nile Valley areas suggest more detrital inputs during the deposition of the phosphorites in Abu Tartur. The products of the diagenesis and weathering of these deposits also reflect the variations in the depositional conditions.
Using Escape Extinction and Reinforcement to Increase Eating in a Young Child with Autism
Authors: Bui Lilly T. D. , Moore Dennis W. , Anderson Angelika
Published: March 2013

Feeding problems that can lead to associated nutritionally related medical conditions and often cause stress and difficulties for parents are prevalent in children with autism. It is therefore important to target these problem behaviours through effective interventions. The present study was designed to trial a procedure comprised of escape extinction combined with positive reinforcement with the aim to reduce food refusals and increase eating in a child with autism. It was predicted that the intervention package would significantly reduce food refusals and increase eating and that any increase in food acceptance would be maintained and generalised to other behaviours related to feeding on termination of the intervention. The research design was a multiple baseline across settings. The results confirmed our predictions. It was concluded that the treatment package was effective at increasing food acceptance.
NONINFERENTIALISM AND TESTIMONIAL BELIEF FIXATION
Authors: Kenyon Tim
Published: March 2013

An influential view in the epistemology of testimony is that typical or paradigmatic beliefs formed through testimonial uptake are noninferential. Some epistemologists in particular defend a causal version of this view: that beliefs formed from testimony (BFT) are generated by noninferential processes. This view is implausible, however. It tends to be elaborated in terms that do not really bear it out – e.g. that BFT is fixed directly, immediately, unconsciously or automatically. Nor is causal noninferentialism regarding BFT plausibly expressed in terms of belief-independent belief formation; the complex cognitive details of BFT fixation do not accord well with such a view. But perhaps the most significant issue is that the relevant causal notion of inference itself is not particularly well-defined, at least with respect to BFT. Causal noninferentialism in this domain is obscure as a result, but this does not in turn clearly vindicate any interesting version of inferentialism.
EPISTEMIC VALUE AND EPISTEMIC COMPROMISE: A REPLY TO MOSS
Authors: Konigsberg Amir
Published: March 2013

Sarah Moss has recently suggested that when they encounter conflict, epistemic peers should not split the difference between the credence that they each assign to some disputed proposition p, as has been suggested by conciliatory approaches to belief revision in the debate surrounding disagreement in the literature. Moss contends that an epistemic compromise between peers need not be the arithmetic mean of prior credences, in the sense that if my credence in some proposition p is x and yours is y, the credence that is the result of our compromise need not be (x + y)/2. More generally, Moss's proposal advocates an approach to how estimations of truth value, exhibited in credences, should in fact be considered in resolving conflict and disagreement. The general idea is that splitting the difference between credences may be inadequate, seeing as agents may assign different epistemic values to different credences. While novel and clearly argued, I think that Moss's proposal fails to provide entirely convincing reasons for abandoning the traditional symmetrical approach to epistemic compromise and for adopting the scoring rule model instead. I demonstrate two problems with the model that Moss advocates.
A NEW EPISTEMIC UTILITY ARGUMENT FOR THE PRINCIPAL PRINCIPLE
Authors: Pettigrew Richard
Published: March 2013

Jim Joyce has presented an argument for Probabilism based on considerations of epistemic utility. In a recent paper, I adapted this argument to give an argument for Probablism and the Principal Principle based on similar considerations. Joyce's argument assumes that a credence in a true proposition is better the closer it is to maximal credence, whilst a credence in a false proposition is better the closer it is to minimal credence. By contrast, my argument in that paper assumed (roughly) that a credence in a proposition is better the closer it is to the objective chance of that proposition. In this paper, I present an epistemic utility argument for Probabilism and the Principal Principle that retains Joyce's assumption rather than the alternative I endorsed in the earlier paper. I argue that this results in a superior argument for these norms.
Reinscribing the Jews: The Story of Aristides’Apology2.2–4 and 14.1b–15.2
Authors: Rutherford William C.
Published: March 2013

In hisApology, Aristides paints a picture of Judaism that commentators have summarily praised as “surprising,” manifesting a “Jewish-friendly spirit,” “very favorable,” bearing “no trace of ill-feeling to the Jews,” “rather mild,” and lacking “every severity of tone, every anti-Jewish polemic.”1In light of these positive notes, it seems rather shocking that scholarship on Aristides has traditionally devoted only cursory and insubstantial attention to his evaluation of the Jews, especially since it informs the study of early Jewish-Christian relations.2Recently Judith Lieu and Denise Kimber Buell have attempted to remedy this gap.3They have invigorated the study ofApologyby approaching the text with a fresh set of questions and by posing solutions based on recent methodologies in literary and ethno-racial analysis. Their informed studies spotlight an “ethnic” discourse inApologyand the controlling influence it plays in Aristides’ construction of a Christian “race” distinguished from other ethnicities, including a Jewish “race.”
Insatiable Desire
Authors: Ellis Fiona
Published: March 2013

Last night I had a desire for a glass of wine. Luckily I had a bottle in the fridge and could satisfy my desire. Earlier in the day I had a desire to run on the heath and I satisfied this desire too. And today, tired of reading yet more stuff on desire, I satisfied my desire to start writing. So desires can be satisfied. Not that they are guaranteed to be satisfied – the bottle in my fridge might have failed to materialize, and something might have prevented me from going for a run or getting down to writing – but that they can be satisfied. Witness C.S. Lewis:

Creatures are not born with desires unless satisfaction for those desires exists. A baby feels hunger: well, there is such a thing as food. A duckling wants to swim: well, there is such a thing as water. Men feel sexual desire: well, there is such a thing as sex.
The prevalence and incidence of dementia with Lewy bodies: a systematic review of population and clinical studies
Authors: Vann Jones S. A. , O'Brien J. T.
Published: March 2013

Background

Dementia with Lewy bodies (DLB) is increasingly recognized as a common cause of dementia in older people. However, its true frequency remains unclear, with previous studies reporting a prevalence range from zero to 22.8% of all dementia cases. This review aimed to establish the population prevalence and incidence for DLB and to compare this to its prevalence in secondary care settings.

Method

A literature review of all relevant population and clinical studies was conducted using PubMed. Additional references from papers found during that process were added to this.

Results

DLB accounted for 4.2% of all diagnosed dementias in the community. In secondary care this increased to 7.5%. The incidence of DLB was 3.8% of new dementia cases. There was a significant increase in DLB diagnoses when using the revised (2005) International Consensus Criteria (ICC) for DLB compared to the original (1996) criteria.

Conclusions

DLB currently accounts for around one in 25 dementia cases diagnosed in the community and one in 13 cases in secondary care. The significantly higher rates of DLB in secondary care may reflect enhanced diagnostic accuracy in specialist settings and/or the increased morbidity and carer burden of the DLB syndrome compared to other dementias. However, the true prevalence is likely to be much higher because DLB diagnoses are often missed, although there is evidence that new criteria aid case identification.
Cognition in schizophrenia and schizo-affective disorder: impairments that are more similar than different
Authors: Owoso A. , Carter C. S. , Gold J. M. , MacDonald A. W. , Ragland J. D. , Silverstein S. M. , Strauss M. E. , Barch D. M.
Published: March 2013

Background

Cognition is increasingly being recognized as an important aspect of psychotic disorders and a key contributor to functional outcome. In the past, comparative studies have been performed in schizophrenia and schizo-affective disorder with regard to cognitive performance, but the results have been mixed and the cognitive measures used have not always assessed the cognitive deficits found to be specific to psychosis. A set of optimized cognitive paradigms designed by the Cognitive Neuroscience Test Reliability and Clinical Applications for Schizophrenia (CNTRACS) Consortium to assess deficits specific to schizophrenia was used to measure cognition in a large group of individuals with schizophrenia and schizo-affective disorder.

Method

A total of 519 participants (188 with schizophrenia, 63 with schizo-affective disorder and 268 controls) were administered three cognitive paradigms assessing the domains of goal maintenance in working memory, relational encoding and retrieval in episodic memory and visual integration.

Results

Across the three domains, the results showed no major quantitative differences between patient groups, with both groups uniformly performing worse than healthy subjects.

Conclusions

The findings of this study suggests that, with regard to deficits in cognition, considered a major aspect of psychotic disorder, schizophrenia and schizo-affective disorder do not demonstrate major significant distinctions. These results have important implications for our understanding of the nosological structure of major psychopathology, providing evidence consistent with the hypothesis that there is no natural distinction between cognitive functioning in schizophrenia and schizo-affective disorder.
Involvement of prelimbic medial prefrontal cortex in panic-like elaborated defensive behaviour and innate fear-induced antinociception elicited by GABAA receptor blockade in the dorsomedial and ventromedial hypothalamic nuclei: role of the endocannabinoid CB1 receptor
Authors: de Freitas Renato Leonardo , Salgado-Rohner Carlos José , Hallak Jaime Eduardo Cecílio , de Souza Crippa José Alexandre , Coimbra Norberto Cysne
Published: March 2013

It has been shown that GABAA receptor blockade in the dorsomedial and ventromedial hypothalamic nuclei (DMH and VMH, respectively) induces elaborated defensive behavioural responses accompanied by antinociception, which has been utilized as an experimental model of panic attack. Furthermore, the prelimbic (PL) division of the medial prefrontal cortex (MPFC) has been related to emotional reactions and the processing of nociceptive information. The aim of the present study was to investigate the possible involvement of the PL cortex and the participation of local cannabinoid CB1 receptors in the elaboration of panic-like reactions and in innate fear-induced antinociception. Elaborated fear-induced responses were analysed during a 10-min period in an open-field test arena. Microinjection of the GABAA receptor antagonist bicuculline into the DMH/VMH evoked panic-like behaviour and fear-induced antinociception, which was decreased by microinjection of the non-selective synaptic contact blocker cobalt chloride in the PL cortex. Moreover, microinjection of AM251 (25, 100 or 400 pmol), an endocannabinoid CB1 receptor antagonist, into the PL cortex also attenuated the defensive behavioural responses and the antinociception that follows innate fear behaviour elaborated by DMH/VMH. These data suggest that the PL cortex plays an important role in the organization of elaborated forward escape behaviour and that this cortical area is also involved in the elaboration of innate fear-induced antinociception. Additionally, CB1 receptors in the PL cortex modulate both panic-like behaviours and fear-induced antinociception elicited by disinhibition of the DMH/VMH through microinjection of bicuculline.
Obsessive–Compulsive Symptoms and Related Sex Differences in Brain Structure: An MRI Study in Dutch Twins
Authors: den Braber Anouk , de Geus Eco J.C. , Boomsma Dorret I. , van ‘t Ent Dennis
Published: March 2013

Neuroimaging studies have indicated abnormalities in cortico-striato-thalamo-cortical circuits in obsessive–compulsive disorder patients, but results have not been consistent. Since there are significant sex differences in human brain anatomy and obsessive–compulsive symptomatology and its developmental trajectories tend to be distinct in males and females, we investigated whether sex is a potential source of heterogeneity in neuroimaging studies on obsessive–compulsive symptoms. We selected male and female twin pairs who were concordant for scoring either high or low for obsessive–compulsive symptoms and a group of discordant pairs where one twin scored high and the co-twin scored low. The design included 24 opposite-sex twin pairs. Magnetic resonance imaging scans of 31 males scoring high for obsessive–compulsive symptoms, 41 low-scoring males, 58 high-scoring females, and 73 low-scoring females were analyzed and the interaction of obsessive–compulsive symptoms by sex on gray matter volume was assessed using voxel-based morphometry. An obsessive–compulsive symptom by sex interaction was observed for the left middle temporal gyrus, the right middle temporal gyrus, and the right precuneus. These interactions acted to reduce or hide a main effect in our study and illustrate the importance of taking sex into account when investigating the neurobiology of obsessive–compulsive symptoms.
Influence of Crystallinity and Energetics on Charge Separation in Polymer–Inorganic Nanocomposite Films for Solar Cells
Authors: Bansal Neha , Reynolds Luke X. , MacLachlan Andrew , Lutz Thierry , Ashraf Raja Shahid , Zhang Weimin , Nielsen Christian B. , McCulloch Iain , Rebois Dylan G. , Kirchartz Thomas , Hill Michael S. , Molloy Kieran C. , Nelson Jenny , Haque Saif A.
Published: March 2013

The dissociation of photogenerated excitons and the subsequent spatial separation of the charges are of crucial importance to the design of efficient donor-acceptor heterojunction solar cells. While huge progress has been made in understanding charge generation at all-organic junctions, the process in hybrid organic:inorganic systems has barely been addressed. Here, we explore the influence of energetic driving force and local crystallinity on the efficiency of charge pair generation at hybrid organic:inorganic semiconductor heterojunctions. We use x-ray diffraction, photoluminescence quenching, transient absorption spectroscopy, photovoltaic device and electroluminescence measurements to demonstrate that the dissociation of photogenerated polaron pairs at hybrid heterojunctions is assisted by the presence of crystalline electron acceptor domains. We propose that such domains encourage delocalization of the geminate pair state. The present findings suggest that the requirement for a large driving energy for charge separation is relaxed when a more crystalline electron acceptor is used.
Single-strand promoter traps for bacterial RNA polymerase
Authors: Pupov Danil , Esyunina Daria , Feklistov Andrey , Kulbachinskiy Andrey
Published: March 2013

Besides canonical double-strand DNA promoters, multisubunit RNAPs (RNA polymerases) recognize a number of specific single-strand DNA and RNA templates, resulting in synthesis of various types of RNA transcripts. The general recognition principles and the mechanisms of transcription initiation on these templates are not fully understood. To investigate further the molecular mechanisms underlying the transcription of single-strand templates by bacterial RNAP, we selected high-affinity single-strand DNA aptamers that are specifically bound by RNAP holoenzyme, and characterized a novel class of aptamer-based transcription templates. The aptamer templates have a hairpin structure that mimics the upstream part of the open promoter bubble with accordingly placed specific promoter elements. The affinity of the RNAP holoenzyme to such DNA structures probably underlies its promoter-melting activity. Depending on the template structure, the aptamer templates can direct synthesis of productive RNA transcripts or effectively trap RNAP in the process of abortive synthesis, involving DNA scrunching, and competitively inhibit promoter recognition. The aptamer templates provide a novel tool for structure–function studies of transcription initiation by bacterial RNAP and its inhibition.
Modelling of free space optical link for ground‐to‐train communications using a Gaussian source
Authors: Paudel Rupak , Ghassemlooy Zabih , Le‐Minh Hoa , Rajbhandari Sujan
Published: March 2013

The demand for access to broadband data services in high‐speed trains is increasing as more people are travelling to and from work, which is not met by the existing radio frequency technology. Therefore an alternative technology known as free space optics (FSO) could be readily adopted that could overcome the bandwidth bottleneck problem. The study presents a mathematical model of an FSO link for ground‐to‐train communications link and analyses the system performance in terms of the signal‐to‐noise ratio and the bit error rate (BER). The authors show that the simulated BER is in good agreement with the predicted results for bit rates up to 50 Mbps. The link budget analysis for the proposed system is also presented showing a link margin of 17.75 dB.
Ferroelastic aspects of relaxor ferroelectric behaviour in Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 perovskite
Authors: Nataf Guillaume F. , Li Qian , Liu Yun , Withers Ray L. , Driver Sarah L. , Carpenter Michael A.
Published: March 2013

Elastic and anelastic properties of poled and depoled single crystals of Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 with compositions close to the morphotropic boundary have been investigated over the temperature range 5–700 K by resonant ultrasound spectroscopy (RUS) at frequencies of 0.1–1.2 MHz. Steep elastic softening occurs in a temperature interval of at least 250 K as the Vogel-Fulcher freezing interval and cubic → tetragonal transition point, Tc, are approached from above. This is understood in terms of coupling between acoustic modes and central peak mode(s) associated with dynamic polar nano regions (PNR's) below the Burns temperature. Acoustic losses occur in a temperature interval of ∼50 K above Tc, associated with slowing down of the PNR dynamics. The cubic ↔ tetragonal and tetragonal ↔ rhombohedral transitions are accompanied by steep minima in elastic properties, closely analogous to the pattern of softening and stiffening observed in sequences of improper ferroelastic transitions in other perovskites. Variations in the magnitudes of acoustic losses at T < Tc correlate with the density of ferroelastic twin walls, from lowest for [001]c-poled and [111]c-poled crystals in the stability fields of the tetragonal and rhombohedral phases, respectively, to highest for unpoled crystals. A simple model of Debye-like peaks in acoustic loss near 100 K has yielded activation energies and attempt frequencies in the same range as those observed from dielectric data in the Vogel-Fulcher freezing interval. These highlight the fact that, in addition to conventional ferroelectric/ferroelastic twin walls, relaxor ferroelectrics contain local structural heterogeneities coupled to strain, which are probably related to the presence of static PNR's preserved even in poled crystals. RUS also provides a convenient and effective means of determining the mechanical quality factor of relaxor ferroelectrics, as functions of both poling history and temperature.
Exchange bias in reduced dimensions: Cobalt nanocluster arrays under the influence of nanometer thin MnPt capping layers
Authors: Sessi V. , Hertenberger S. , Zhang J. , Schmitz D. , Gsell S. , Schreck M. , Morel R. , Brenac A. , Honolka J. , Kern K.
Published: March 2013

The magnetic behavior of cobalt nanocluster arrays arranged on a boron-nitride nanomesh and capped with MnPt layers of varying thickness θMnPt is investigated. The magnetic properties of the arrays are found to be strongly dependent on the cobalt nanocluster size: large 3-dimensional clusters of several nanometers size under the influence of only θMnPt∼5 nm exhibit prototypical exchange bias behavior, whereas small 2-dimensional clusters of about 1 nm in diameter show superparamagnetic behavior, however, with a strong quenching of the average cobalt magnetization. The latter effect is correlated with the formation of a stable antiferromagnetic phase at increasing θMnPt and is discussed in terms of the domain state exchange bias model. The quenching suggests either partial antiferromagnetic alignment of cobalt spins within a cluster or a random orientation of cobalt cluster macrospins with respect to each other.
Thermally induced degradation of condensation-grown (100)Ge0.75Si0.25/SiO2 interfaces revealed by electron spin resonance
Authors: Kepa J. , Stesmans A. , Afanas'ev V. V.
Published: March 2013

The thermal stability under isochronal annealing of the GeSi/SiO2 interfaces in the condensation grown silicon-germanium-on-insulator (100)Si/SiO2/Ge0.75S0.25/SiO2 structure has been assessed by electron spin resonance in terms of occurring interface defects. As to annealing in vacuum, this reveals thermal post-growth interface degradation, from ∼440 °C onward, on atomic scale as substantial generation of Ge dangling bond (GePb1) interface defects, previously identified as detrimental electron traps. A similar behavior is observed for annealing in H2 (∼1 atm), except that the interface degradation evolves more gradually. The data bear out that the temperature of technological H2 passivation treatments should not exceed ∼440 °C.
Pulsed laser-deposited VO2 thin films on Pt layers
Authors: Sakai Joe , Zaghrioui Mustapha , Ta Phuoc Vinh , Roger Sylvain , Autret-Lambert Cécile , Okimura Kunio
Published: March 2013

VO2 films were deposited on Pt (111)/TiO2/SiO2/Si (001) substrates by means of a pulsed laser deposition technique. An x-ray diffraction peak at 2θ = 39.9° was deconvoluted into two pseudo-Voigt profiles of Pt (111) and VOx-originated components. The VOx diffraction peak was more obvious in a VOx/Pt (111)/Al2O3 (0001) sample, having a narrower width compared with a VO2/Al2O3 (0001) sample. Temperature-controlled Raman spectroscopy for the VOx/Pt/TiO2/SiO2/Si sample has revealed the monoclinic VO2 phase at low temperature and the structural phase transition at about 72 °C in a heating process. The electronic conductive nature at the high temperature phase was confirmed by near normal incidence infrared reflectivity measurements. Out-of-plane current-voltage characteristics showed an electric field-induced resistance switching at a voltage as low as 0.2 V for a 50 nm-thick film. A survey of present and previous results suggests an experimental law that the transition voltage of VO2 is proportional to the square root of the electrodes distance.
Semiconducting selenium nanoparticles: Structural, electrical characterization, and formation of a back-to-back Schottky diode device
Authors: Sinha Subhojyoti , Kumar Chatterjee Sanat , Ghosh Jiten , Kumar Meikap Ajit
Published: March 2013

Well crystalline selenium nanoparticles having an optical band gap of 2.95 eV have been synthesized using oxalic acid. Microstructural parameters such as crystallite size, lattice strain, cell parameters, and unit cell volume are estimated from X-ray diffraction line profile analysis by Rietveld refinement technique. dc and ac transport properties of the nanoparticles in the temperature range 300 K ≤ T ≤ 390 K and frequency range 20 Hz ≤ f ≤ 2 MHz have also been studied. The values of dc activation energies in the low and high temperature regions are found to be 0.083 eV and 0.382 eV, respectively. The charge transport mechanism of the sample follows correlated barrier hopping (CBH) model and the calculated value of barrier height and relaxation time is 0.786 eV and 2.023 × 10−11 s, respectively, while grain boundary contribution being greater than the grain contribution. Considering metal electrode-semiconductor contact as a back-to-back Schottky diode device, analysis of the current-voltage and capacitance-voltage characteristics is done to extract the Schottky barrier heights, ideality parameters, built in voltage, and charge density. With ±40 V sweep the capacitance versus voltage characteristics of the sample shows hysteresis behavior which may be attributed to the presence of deep traps.
Comparing different coarse-grained potentials for star polymers
Authors: Menichetti Roberto , Pelissetto Andrea
Published: March 2013

We compare different coarse-grained single-blob models for star polymers. We find that phenomenological models inspired by the Daoud-Cotton theory reproduce quite poorly the thermodynamics of these systems, even if the potential is assumed to be density dependent, as done in the analysis of experimental results. Using the numerically determined coarse-grained potential, we also determine the minimum value fc of the functionality of the star polymer for which a fluid-solid transition occurs. By applying the Hansen-Verlet criterion we find 35 < fc ≲ 40. This result is confirmed by an analysis that uses the modified (reference) hypernetted chain method and is qualitatively consistent with previous work.
Effect of the Zn content in the magnetic properties of Co1−xZnxFe2O4 mixed ferrites
Authors: Franco A. , e Silva F. C.
Published: March 2013

In this work, the effect of Zn content in the magnetic properties of Co1−xZnxFe2O4 (0.0 ≤ x ≤ 1.0) nanoparticles synthesized by combustion reaction method was investigated by applying magnetic fields up to 20 kOe at room temperature. All the samples were found to have a cubic spinel structure and the lattice parameter increases linearly with increasing Zn-content. The hysteresis loops yield a saturation magnetization (Ms), coercive field (Hc), and remanent magnetization (Mr) that varies significantly with Zn-content. For instance, Ms, Hc, and Mr are 70 emu/g, 600 Oe, and 20 emu/g and 8 emu/g, 0.0 Oe, and 0.0 emu/g for x = 0.0 and x = 1.0, respectively. The Curie temperature determined by means of the inverse susceptibility versus temperature decreases with increasing x, being ∼787 K and ∼634 K for x = 0.0 and 1.0, respectively. The magnetic cubic anisotropy constant for different Zn-contents, determined by a “law of approach” to saturation, was found to be smaller than those values for pure cobalt ferrites nanoparticles and strongly dependent on x, being 3.87 × 106 erg/cm3 and 0.22 × 106 erg/cm3 for x = 0.0 and 1.0, respectively, at room temperature. A discussion on the implications of the Zn-content in the determination of the anisotropy constant in these materials will also be presented.
The anomalous Hall effect in the perpendicular Ta/CoFeB/MgO thin films
Authors: Wu S. B. , Zhu T. , Yang X. F. , Chen S.
Published: March 2013

The anomalous Hall effect (AHE) in the perpendicular Ta/CoFeB/MgO thin film has been investigated. Between the AHE coefficient (RS) and longitudinal resistivity (ρxx), a linear behavior of RS/ρxx versus ρxx can be found. Moreover, the conductivity of the film is about 5 × 103 S/cm, which suggests that AHE in the Ta/CoFeB/MgO film be dominated by the intrinsic or scattering-independent mechanism.
Magnetic resonance imaging of microvessels using iron-oxide nanoparticles
Authors: Olamaei N. , Cheriet F. , Martel S.
Published: March 2013

The visualization of microstructures including blood vessels with an inner overall cross-sectional area below approximately 200 μm remains beyond the capabilities of current clinical imaging modalities. But with magnetic resonance (MR) imaging, magnetic entities cause susceptibility artifacts in the images by disrupting the homogeneous magnetic field in a much larger scale than their actual size. As validated in this paper through simulation and in-vitro experiments, these artifacts can serve as a source of contrast, enabling microvessels with an inner diameter below the spatial resolution of any medical imaging modalities to be visualized using a clinical MR scanner. For such experiments, micron-sized agglomerations of iron-oxide (Fe3O4) nanoparticles were injected in microchannels with internal diameters of 200 and 50 μm equivalent to a narrower artery or a larger arteriole, and down to a smaller arteriole, respectively. The results show the feasibility of the proposed method for micro-particle detection and the visualization of microvessels using a 1.5 T clinical MR scanner. It was confirmed that the method is reproducible and accurate at the sub-pixel level.
Silicon-on-nitride waveguides for mid- and near-infrared integrated photonics
Authors: Khan Saeed , Chiles Jeff , Ma Jichi , Fathpour Sasan
Published: March 2013

Silicon-on-nitride ridge waveguides are demonstrated and characterized at mid- and near-infrared optical wavelengths. Silicon-on-nitride thin films were achieved by bonding a silicon handling die to a silicon-on-insulator die coated with a low-stress silicon nitride layer. Subsequent removal of the silicon-on-insulator substrate results in a thin film of silicon on a nitride bottom cladding, readily available for waveguide fabrication. At the mid-infrared wavelength of 3.39 μm, the fabricated waveguides have a propagation loss of 5.2 ± 0.6 dB/cm and 5.1 ± 0.6 dB/cm for the transverse-electric and transverse-magnetic modes, respectively.
Kinetics and Dynamics of Photocatalyzed Dissociation of Ethanol on TiO2(110)
Authors: Ma Zhi-bo , Zhou Chuan-yao , Mao Xin-chun , Ren Ze-feng , Dai Dong-xu , Yang Xue-ming
Published: March 2013

The kinetics and dynamics of photocatalyzed dissociation of ethanol on TiO2(110) surface have been studied using the time-dependent and time-resolved femtosecond two-photon photoemission spectroscopy respectively, in order to unravel the photochemical properties of ethanol on this prototypical metal oxide surface. By monitoring the time evolution of the photoinduced excited state which is associated with the photocatalyzed dissociation of ethanol on Ti5c sites of TiO2(110), the fractal-like kinetics of this surface photocatalytic reaction has been obtained. The measured photocatalytic dissociation rate on reduced TiO2(110) is faster than that on the oxidized surface. This is attributed to the larger defect density on the reduced surface which lowers the reaction barrier of the photocatalytic reaction at least methodologically. Possible reasons associated with the defect electrons for the acceleration have been discussed. By performing the interferometric two-pulse correlation on ethanol/TiO2(110) interface, the ultrafast electron dynamics of the excited state has been measured. The analyzed lifetime (24 fs) of the excited state is similar to that on methanol/TiO2(110). The appearance of the excited state provides a channel to mediate the electron transfer between the TiO2 substrate and its environment. Therefore studying its ultrafast electron dynamics may lead to the understanding of the microscopic mechanism of photocatalysis and photoelectrochemical energy conversion on TiO2.
Collisional Line Assignments and Hyperfine Structure Interpretation in Cs2 23Δ1g State
Authors: Li Dan , Xie Feng , Li Li , Ahmed Ergin H. , Lyyra A. Marjatta
Published: March 2013

Accurately known energy level structure of the Cs2 A1Σu+−b3Πu complex of states from a recent global de-perturbation of these states has enabled additional assignments of 140 perturbation facilitated infrared-infrared double resonance (PFIIDR) transitions to the 23Δ1g state from collisionally populated intermediate A1Σu+ levels. Together with the 221 previously observed 23Δ1g←A1Σu+←X1Σg+ double resonance lines [J. Chem. Phys. 128, 204313 (2008)], molecular constants and the Rydberg-Klein-Rees potential energy curve of the 23Δ1g state have been recalculated (excluding 54 perturbed levels). The centrifugal distortion constant has been determined and agrees well with the value calculated based on standard empirical formulas. The hyperfine structure of the 23Δg state, which has not resolved in our sub-Doppler excitation spectra of the 23Δ1g state, has been interpreted with a preliminary simulation.
Methanol Perturbing Modeling Cell Membranes Investigated using Linear and Nonlinear Vibrational Spectroscopy
Authors: Tian Kangzhen , Li Hongchun , Ye Shuji
Published: March 2013

Cell membranes play a crucial role in many biological functions of cells. A small change in the composition of cell membranes can strongly influence the functions of membrane-associated proteins, such as ion and water channels, and thus mediate the chemical and physical balance in cells. Such composition change could originate from the introduction of short-chain alcohols, or other anesthetics into membranes. In this work, we have applied sum frequency generation vibrational spectroscopy (SFG-VS), supplemented by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), to investigate interaction between methanol and 1,2-dimyristoyl-d54-sn-glycero-3-phosphocholine (d54-DMPC) lipid bilayers. Lipid's hydrocarbon interior is deuterated while its head group is hydrogenated. At the same time, CH3 symmetric stretch from methanol and lipid head amine group has different frequency, thus we can distinguish the behaviors of methanol, lipid head amine group, and lipid hydrocarbon interior. Based on the spectral feature of the bending mode of the water molecules replaced by methanol, we determined that the methanol molecules are intercalated into the region between amine and phosphate groups at the lipid hydrophilic head. The dipole of CH3 groups of methanol and lipid head, and the water O-H all adopt the same orientation directions. The introduction of methanol into the lipid hydrophilic head group can strongly perturb the entire length of the alkyl chains, resulting that the signals of CD2 and CD3 groups from both leaflets can not cancel each other.
Conformations of Carnosine in Aqueous Solutions by All-Atom Molecular Dynamics Simulations and 2D-NOSEY Spectrum
Authors: Zhang Rong , Wang Dan , Wu Wen-juan
Published: March 2013

All-atom molecular simulations and two-dimensional nuclear overhauser effect spectrum have been used to study the conformations of carnosine in aqueous solution. Intramolecular distances, root-mean-square deviation, radius of gyration, and solvent-accessible surface are used to characterize the properties of the carnosine. Carnosine can shift between extended and folded states, but exists mostly in extended state in water. Its preference for extension in pure water has been proven by the 2D nuclear magnetic resonance (NMR) experiment. The NMR experimental results are consistent with the molecular dynamics simulations.
Greenhouse gas emissions profile for 1 kg of wool produced in the Yass Region, New South Wales: A Life Cycle Assessment approach
Authors: Brock Philippa M. , Graham Phillip , Madden Patrick , Alcock Douglas J.
Published: March 2013

The use of Life Cycle Assessment (LCA) to determine environmental impacts of agricultural production, as well as production by other industry sectors has increased. LCA provides an internationally accepted method to underpin labelling and marketing of agricultural products, a valuable tool to compare emissions reduction strategies and a means to identify perverse policy outcomes. A single-issue LCA focussing on greenhouse gas emissions was conducted to determine the emissions profile and carbon footprint of 19-micron wool produced in the Yass Region on the Southern Tablelands of New South Wales. Greenhouse gas emissions (in carbon dioxide equivalents; CO2-e) from the production of all enterprise inputs and from the production of wool on-farm were included. Total emissions were found to be 24.9 kg CO2-e per kg of greasy wool at the farm gate, based on a 4941 breeding ewe enterprise on 1000 ha, with a total greasy wool yield of 65.32 t per annum. The co-products included 174 t sheep meat as liveweight from wethers and cull ewes plus 978 maiden ewes sold off-farm as replacement stock. Total emissions from all products grown on 1000 ha were 2899 t CO2-e per annum.
The relative contribution of greenhouse gas emissions from different components of the production system was determined. Direct emission of methane on-farm (86% of total) was the dominant emission, followed by nitrous oxide emitted from animal wastes directly (5%) and indirectly (5%), and decomposition of pasture residue (1%). Only 2% of total emissions were embodied in farm inputs, including fertiliser.
The emissions profile varied according to calculation method and assumptions. Enteric methane production was calculated using five recognised methods and results were found to vary by 27%. This study also showed that calculated emissions for wool production changed substantially, under an economic allocation method, by changing the enterprise emphasis from wool to meat production (41% decrease) and by changing wool price (29% variability), fibre diameter (23% variability) and fleece weight (11% variability). This paper provides data specific to the Yass Region and addresses broader methodological issues, to ensure that future livestock emissions calculations are robust.
Historical fire–climate relationships of upper elevation fire regimes in the south-western United States
Authors: Margolis Ellis Q. , Swetnam Thomas W.
Published: March 2013

Understanding relationships between variability in historical fire occurrence and ocean–atmosphere oscillations provides opportunities for fire forecasting and projecting changes in fire regimes under climate change scenarios. We analysed tree-ring reconstructed regional climate teleconnections and fire–climate relationships in upper elevation forests (>2700m) from 16 sites in eight mountain ranges in the south-western USA. Climate teleconnections were identified by testing for associations between regional Palmer Drought Severity Index (PDSI) and individual and combined phases of El Niño–Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO) and Atlantic Multidecadal Oscillation (AMO) indices for both the fire exclusion (1905–1978) and reconstructed fire periods (1700–1904). Fire–climate relationships were identified by comparing reconstructed fires (84 fire years) in three classes (all, synchronous and stand-replacing fires) with PDSI, precipitation, temperature, and individual and combined phases of ENSO, PDO and AMO indices. Individual and phase combinations of ENSO, PDO and AMO were associated with variability in regional PDSI. Upper elevation fire occurrence was related to variability in regional drought, ENSO phase and phase combinations of ENSO and PDO. We conclude that ENSO most consistently influenced variability in moisture and upper elevation fire occurrence, including stand-replacing fires, but this relationship was potentially modulated by phases of the PDO.