bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of Trace Metal Anomalies for Recognition of Petroleum Prospects in Surface Sediments of Kutch and Saurashtra Basins, India
Authors: Radha B. Anu , Srinivasa Rao P. L. , Rasheed M. A. , Patil D. J. , Dayal A. M.
Published: January 2013

Seepage of hydrocarbons, either as macroseepage or microseepage, can set up near-surface oxidation-reduction zones that favour the development of a diverse array of chemical and mineralogic changes. In this study trace metal alterations were mapped that appear to be associated with hydrocarbon microseepages in the oil/gas fields. A total of 210 soil samples were collected from near surface sediments of Kutch and Saurashtra Basins, India. The soil samples were collected from a depth of 2 - 2.5 m. The paper reports the chemical alterations associated with trace metals in soils that are related to hydrocarbon microseepages above the Kutch and Saurashtra Basins, India. The soil samples for trace metals; Scandium (Sc), Vanadium (V), Chromium (Cr), Cobalt (Co), Nickel (Ni), Copper (Cu), Zinc (Zn), Barium (Ba) and Strontium (Sr) were analyzed using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The concentrations of the trace elements ranged between for Sc (12.69 to 21.91 ppm), V (109.20 to 436.05 ppm), Cr (87.15 to 481.57 ppm), Co (18.25 to 64.31 ppm), Ni (57.55 to 263.15 ppm), Cu (44.88 to 143.96 ppm), Zn (137.60 to 502.31 ppm), Ba (149.27 to 921.46 ppm) and Sr (143.93 to 425.63 ppm) were obtained. It was observed that trace elements concentrations were tremendously increased when compared with normal concentration in the soils. The adsorbed soil gas analysis showed the presence of high concentrations of ∑C2+ (C2H6, C3H8 and n-C4H10) ranged between 1 to 121 ppb respectively. Integrated studies of trace elements over adsorbed light gaseous hydrocarbon (∑C2+) anomalies showed good correlation. The carbon isotopic composition of δ13C1 of the samples ranges between – 36.6 ‰ to -22.7‰ (Pee Dee Belemnite) suggest thermogenic source for hydrocarbon gases. The increase in trace metal concentrations near oil/gas producing areas, suggests that soil chemical change to a reducing environment, presumably due to the influence of hydrocarbon microseepage, which could be applied with other geo-scientific data to identify areas of future hydrocarbon exploration in the frontier areas.
Eclogitic Metasediments from Central Qiangtang, Northern Tibet: Evidence for Continental Subduction during the Eastern and Western Qiangtang Collision
Authors: Tang Xian-Chun , Zhang Yu-Xiu
Published: January 2013

Eclogitic metasediments from the central Qiangtang metamorphic terrane provide new insights into the continental subduction during the eastern and western Qiangtang collision. Petrologic observations show that the metasediments correspond to meta-sandstones of a continental margin. It is characterized by the garnet + omphacite + rutile + phengite + quartz assemblage, and the peak metamorphic temperature and pressure were estimated to be 535 ± 40°C and ∼27 kbar, respectively, by major element partitioning thermobarometry. Subsequent retrogression occurred at ∼472 ± 30°C and ∼6-9 kbar. The occurrence of eclogitized central Qiangtang terrane indicates the subduction of the western Qiangtang passive continental margin beneath eastern Qiangtang when eastern and western Qiangtang collided along the Shuanghu suture.
Whey protein hydrolysates decrease IL-8 secretion in lipopolysaccharide (LPS)-stimulated respiratory epithelial cells by affecting LPS binding to Toll-like receptor 4
Authors: Iskandar Michèle M. , Dauletbaev Nurlan , Kubow Stan , Mawji Nadir , Lands Larry C.
Published: January 2013

Whey proteins (WP) exert anti-inflammatory and antioxidant effects. Hyperbaric pressurisation of whey increases its digestibility and changes the spectrum of peptides released during digestion. We have shown that dietary supplementation with pressurised whey improves nutritional status and systemic inflammation in patients with cystic fibrosis (CF). Both clinical indices are largely affected by airway processes, to which respiratory epithelial cells actively contribute. Here, we tested whether peptides released from the digestion of pressurised whey can attenuate the inflammatory responses of CF respiratory epithelial cells. Hydrolysates of pressurised WP (pWP) and native WP (nWP, control) were generatedin vitroand tested for anti-inflammatory properties judged by the suppression of IL-8 production in CF and non-CF respiratory epithelial cell lines (CFTE29o- and 1HAEo-, respectively). We observed that, in both cell lines, pWP hydrolysate suppressed IL-8 production stimulated by lipopolysaccharide (LPS) to a greater magnitude compared with nWP hydrolysate. Neither hydrolysate suppressed IL-8 production induced by TNF-α or IL-1β, suggesting an effect on the Toll-like receptor (TLR) 4 pathway, the cellular sensor for LPS. Further, neither hydrolysate affected TLR4 expression or neutralised LPS. Both pWP and nWP hydrolysates similarly reduced LPS binding to surface TLR4, while pWP tended to more potently increase extracellular antioxidant capacity. In conclusion: (1) anti-inflammatory properties of whey are enhanced by pressurisation; (2) suppression of IL-8 production may contribute to the clinical effects of pressurised whey supplementation on CF; (3) this effect may be partly explained by a combination of reduced LPS binding to TLR4 and enhanced extracellular antioxidant capacity.
L’égalité, le possible et ce que les «hommes devraient “pouvoir être”» : sur La gauche et l’égalité de Jean-Michel Salanskis
Authors: Macdonald Iain
Published: January 2013

RÉSUMÉ : La gauche et l’égalité de Jean-Michel Salanskis cherche à faire le bilan des principes traditionnels de la gauche afin de la guérir de certaines illusions et de renouveler ce qui est, pour lui, son pilier central : la quête de l’égalité. Mais pour ce faire, il déploie un concept de possibilité ambigu et problématique qui pourrait mettre en péril la cohérence de son projet. La présente étude analyse le texte de Salanskis en décortiquant son concept de possibilité, et propose quelques ajustements afin d’éviter certains écueils classiques dans l’histoire de la pensée dialectique.
HOMOSEXUALITY AND EPISTEMIC CLOSURE IN MODERN ARABIC LITERATURE
Authors: Hadeed Khalid
Published: January 2013

In this paper I argue that representations of homosexuality in modern Arabic literature have tended to isolate it and contain its threat through a conceptual strai(gh)tjacket that I term “epistemic closure.” I begin by analyzing Saʿd Allah Wannus's playTuqus al-Isharat wa-l-Tahawwulatas an essentialist paradigm of closure, where a language of interiority and essence identifies male homosexuality with passivity and femininity, subordinated a priori to a sexually and socially dominant masculinity. Then, I examine ʿAlaʾ al-Aswani's novelʿImarat Yaʿqubyanas a constructionist example of the same closure, in which homosexuality is explained through a narrative of abnormal development that circumscribes its diffuse potential. Finally, I read Huda Barakat'sSayyidi wa-Habibias a “queer” novel that links homosexuality to the continuum of male homosocial desire, thereby disrupting the normative distribution of center and margin and suggesting a way out of the epistemic closure imposed on homosexuality.
Laser wakefield compression and acceleration of externally injected electron bunches in guiding structures
Authors: ANDREEV N. E. , BARANOV V. E. , CROS B. , MAYNARD G. , MORA P. , VEYSMAN M. E.
Published: January 2013

For the considered scheme of the external electron bunch injection in front of a laser pulse, the influence of the nonlinear driving laser pulse dynamics and electron bunch self-action to the processes of electron bunch compression and acceleration in the laser wakefield is analyzed. Self-consistent modelling results confirm that the nonlinear laser pulse dynamics limits the bunch compression due to variations of the phase velocity of the wake. A growth of the injected bunch charge leads to some extent to an increase of the trapped and accelerated bunch charge and to decrease of the trapped bunch radius and emittance due to increased self-focusing bunch. The three-dimensional theoretical model is elaborated and used to describe the propagation of laser pulses in dielectric capillary waveguides under imperfect coupling and focusing conditions with broken cylindrical symmetry. The role of cone entrances to the cylindrical part of a capillary is analyzed, and it is demonstrated that matching cones can considerably increase the transmission of laser pulses through the capillary, but cannot mitigate the requirements on the precision of the laser pulse focusing into a capillary. In order to avoid a speckle structure and strong transverse gradients of the fields, which can prevent the process of regular electron bunch acceleration, one has to ensure a small laser angle of incidence into the capillary not exceeding 1 mrad.
Soft X-ray continuum radiation from low-energy pinch discharges of hydrogen
Authors: MILLS R. , BOOKER R. , LU Y.
Published: January 2013

Under a study contracted by GEN3 Partners, spectra of high current pinch discharges in pure hydrogen and helium were recorded in the extreme ultraviolet radiation region at the Harvard Smithsonian Center for Astrophysics (CfA) in an attempt to reproduce experimental results published by BlackLight Power, Inc. (BLP) showing predicted continuum radiation due to hydrogen in the 10–30 nm region (Mills, R. L. and Lu, Y. 2010 Hydrino continuum transitions with cutoffs at 22.8 nm and 10.1 nm. Int. J. Hydrog. Energy35, 8446–8456, doi:10.1016?j.ijhydene.2010.05.098). Alternative explanations were considered to the claimed interpretation of the continuum radiation as being that emitted during transitions of H to lower-energy states (hydrinos). Continuum radiation was observed at CfA in the 10–30 nm region that matched BLP's results. Considering the low energy of 5.2 J per pulse, the observed radiation in the energy range of about 120–40 eV, reference experiments and analysis of plasma gases, cryofiltration to remove contaminants, and spectra of the electrode metal, no conventional explanation was found in the prior or present work to be plausible including contaminants, electrode metal emission, and Bremsstrahlung, ion recombination, molecular or molecular ion band radiation, and instrument artifacts involving radicals and energetic ions reacting at the charge-coupled device and H2 re-radiation at the detector chamber. Moreover, predicted selective extraordinarily high-kinetic energy H was observed by the corresponding Doppler broadening of the Balmer α line.
COUNTERPOINT PIECE: THE CASE FOR VARIETY IN CORRECTIVE FEEDBACK RESEARCH
Authors: Lyster Roy , Ranta Leila
Published: January 2013

Goo and Mackey (this issue) outline several apparent design flaws in studies that have compared the impact of different types of corrective feedback (CF). Furthermore, they argue that SLA researchers should stop comparing recasts to other types of CF because they are inherently different kinds of phenomena. Our response to their article addresses (a) the claim that the recast-learning relationship has been “settled,” (b) the misleading representation of our views on uptake, (c) the characterization of the CF comparison studies as being weak and invalid, and (d) Goo and Mackey’s recommendations concerning the most appropriate approach to investigating the effect of feedback on second language learning.
Early grammatical development in Spanish children with Down syndrome
Authors: GALEOTE MIGUEL , SOTO PILAR , SEBASTIÁN EUGENIA , CHECA ELENA , SÁNCHEZ-PALACIOS CONCEPCIÓN
Published: January 2013

The objective of this work was to analyze morphosyntactic development in a wide sample of children with Down syndrome (DS) (n = 92) and children with typical development (TD) (n = 92) with a mental age (MA) of 20 to 29 months. Children were individually matched for gender and MA (Analysis 1) and for vocabulary size (Analysis 2). Information about morphosyntax was obtained using an adaptation of the CDI for children with DS. In both analyses, the number of children with DS and with TD who combined words was similar. Analysis 1 showed that children with DS produced shorter utterances, with less morphosyntactic complexity and less morphological suffixes than children with TD, despite having the same mental age. The developmental pattern was similar, although slower in children with DS. Analysis 2 showed that the performance of children with DS was lower than the performance of children with TD in relation to morphosyntactic complexity and morphological suffixes.
Acute myocardial infarctions, strokes and influenza: seasonal and pandemic effects
Authors: FOSTER E. D. , CAVANAUGH J. E. , HAYNES W. G. , YANG M. , GERKE A. K. , TANG F. , POLGREEN P. M.
Published: January 2013

The incidence of myocardial infarctions and influenza follow similar seasonal patterns. To determine if acute myocardial infarctions (AMIs) and ischaemic strokes are associated with influenza activity, we built time-series models using data from the Nationwide Inpatient Sample. In these models, we used influenza activity to predict the incidence of AMI and ischaemic stroke. We fitted national models as well as models based on four geographical regions and five age groups. Across all models, we found consistent significant associations between AMIs and influenza activity, but not between ischaemic strokes and influenza. Associations between influenza and AMI increased with age, were greatest in those aged >80 years, and were present in all geographical regions. In addition, the natural experiment provided by the second wave of the influenza pandemic in 2009 provided further evidence of the relationship between influenza and AMI, because both series peaked in the same non-winter month.
Losses of functional opsin genes, short-wavelength cone photopigments, and color vision—A significant trend in the evolution of mammalian vision
Authors: JACOBS GERALD H.
Published: January 2013

All mammalian cone photopigments are derived from the operation of representatives from two opsin gene families (SWS1 and LWS in marsupial and eutherian mammals; SWS2 and LWS in monotremes), a process that produces cone pigments with respective peak sensitivities in the short and middle-to-long wavelengths. With the exception of a number of primate taxa, the modal pattern for mammals is to have two types of cone photopigment, one drawn from each of the gene families. In recent years, it has been discovered that the SWS1 opsin genes of a widely divergent collection of eutherian mammals have accumulated mutational changes that render them nonfunctional. This alteration reduces the retinal complements of these species to a single cone type, thus rendering ordinary color vision impossible. At present, several dozen species from five mammalian orders have been identified as falling into this category, but the total number of mammalian species that have lost short-wavelength cones in this way is certain to be much larger, perhaps reaching as high as 10% of all species. A number of circumstances that might be used to explain this widespread cone loss can be identified. Among these, the single consistent fact is that the species so affected are nocturnal or, if they are not technically nocturnal, they at least feature retinal organizations that are typically associated with that lifestyle. At the same time, however, there are many nocturnal mammals that retain functional short-wavelength cones. Nocturnality thus appears to set the stage for loss of functional SWS1 opsin genes in mammals, but it cannot be the sole circumstance.
SAM HARRIS, THE MORAL LANDSCAPE, AND SOME UNANSWERED QUESTIONS
Authors: Vroman Brian
Published: January 2013

In this dialogue, two college students, Katie and Dennis, discuss some of the positions taken by Sam Harris in his recent work The Moral Landscape. They discover that, first, theories of ethics based on human well-being are nothing new; they also question whether Harris has truly closed the door on moral subjectivism. Next, while remaining sympathetic to Harris, they question how much he has really accomplished by equating human well-being with specific brain states, and wonder if blissful brain states based on delusion can really be associated with a life well lived.
RESPONSIBILITY AND THE VALUE OF CHOICE
Authors: Scanlon T. M.
Published: January 2013

Imagine that you are struggling to finish a project, with the deadline fast approaching. Nearly done, you are about to print out what you have finished when a dialog box appears on your computer screen telling you that you must download and install an update for some piece of software. Frustrated, you try to make it go away, but it keeps reappearing. So you relent and click on ‘Install’, and your screen is filled with small print listing ‘Terms and Conditions’. You do not have time to scroll through the whole thing. So you click ‘Agree’. The installation begins, and you are relieved that it takes only a few minutes. Soon you are back at work and have finished your project.
THE MEANING AND THE MYSTERY OF LIFE
Authors: Peddle Laurence
Published: January 2013

Let us begin with the familiar view that life has a meaning only insofar as we make it meaningful in the way that we live. This is to focus on the value of each individual life, in which respect it may be contrasted with human destiny as being part of a greater scheme of things, as when we look to religion to give significance to our lives beyond our earthly pursuits. What is implied, then, is that human life is devoid of any transcendent meaning, so that we are not the protagonists in a cosmic drama starring Christian or other deities, the final act being that in which we depart this life and set sail for another. On the contrary, when we die we sink into oblivion, and that is all there is to it.
LOCKE'S SECOND ‘SECRET REFERENCE’
Authors: Moore Terence
Published: January 2013

Locke's analysis of the origins of meaning is clear, coherent, cogent and devastating to our commonsense beliefs. His analysis establishes that in the last resort the meaning, he would say ‘Signification’, of words is ineluctably private, subjective, personal. Where meanings are concerned we are, Locke judged, irremediably solipsistic. ‘Words’, he notes, ‘in their primary or immediate Signification stand for nothing but Ideas in the Mind of him that uses them.’
Genetic diversity among potato species as revealed by phenotypic resistances and SSR markers
Authors: Carputo D. , Alioto D. , Aversano R. , Garramone R. , Miraglia V. , Villano C. , Frusciante L.
Published: January 2013

The evolutionary diversity of wild potato species makes them excellent materials for improving the narrow genetic basis of the cultivated potatoSolanum tuberosum. Understanding their genetic diversity is important not only to choose the best parents for breeding, but also to design proper crossing schemes and selection strategies. The objectives of this study were to determine the resistance response toRalstonia solanacearum,Potato virus Yand low temperatures of 21 clones of 12 potato species, and to determine their genetic diversity through simple sequence repeat (SSR) markers. Sources of resistance have been found for all the investigated traits, with high resistance variability not only between but also within species. Combined resistances were also identified, with positive implications for efficient breeding. SSR analysis allowed the detection of 12 loci and 46 alleles across all genotypes, with an average value of 3.8 alleles per locus. Both unique and rare alleles useful for marker-assisted selection were found. SSR-based cluster analysis revealed that resistant genotypes were distributed among all clusters, suggesting that genetically different resistant genotypes were identified. The information obtained in this study is discussed from a breeding perspective.
Developing a Single-Pilot Line Operations Safety Audit
Authors: Earl Laurie , Bates Paul R. , Murray Patrick S. , Ian Glendon A. , Creed Peter A.
Published: January 2013

A single-pilot form of the line operations safety audit was trialed with a mid-sized emergency medical service air operator using two observers with a sample of pilots flying 14 sectors. The conceptual basis for observing pilot performance and analyzing data was the threat and error management model, focusing on threats, errors, undesired aircraft states, and their management. Forty-six threats and 42 crew errors were observed. Pilots generally used sound strategies to prevent errors and to manage successfully those that occurred. Threats resulting from operational pressures were well managed. The study achieved its objective of determining whether a single-pilot line operations safety audit could be successfully developed and used as a basis for systematic data collection.
Invited Review Article: Recent developments in isotope-ratio mass spectrometry for geochemistry and cosmochemistry
Authors: Ireland Trevor R.
Published: January 2013

Mass spectrometry is fundamental to measurements of isotope ratios for applications in isotope geochemistry, geochronology, and cosmochemistry. Magnetic-sector mass spectrometers are most common because these provide the best precision in isotope ratio measurements. Where the highest precision is desired, chemical separation followed by mass spectrometric analysis is carried out with gas (noble gas and stable isotope mass spectrometry), liquid (inductively coupled plasma mass spectrometry), or solid (thermal ionization mass spectrometry) samples. Developments in in situ analysis, including ion microprobes and laser ablation inductively coupled plasma mass spectrometry, have opened up issues concerning homogeneity according to domain size, and allow ever smaller amounts of material to be analyzed. While mass spectrometry is built solidly on developments in the 20th century, there are new technologies that will push the limits in terms of precision, accuracy, and sample efficiency. Developments of new instruments based on time-of-flight mass spectrometers could open up the ultimate levels of sensitivity per sample atom.
Efficient distance-including integral screening in linear-scaling Møller-Plesset perturbation theory
Authors: Maurer Simon A. , Lambrecht Daniel S. , Kussmann Jörg , Ochsenfeld Christian
Published: January 2013

Efficient estimates for the preselection of two-electron integrals in atomic-orbital based Møller-Plesset perturbation theory (AO-MP2) theory are presented, which allow for evaluating the AO-MP2 energy with computational effort that scales linear with molecular size for systems with a significant HOMO-LUMO gap. The estimates are based on our recently introduced QQR approach [S. A. Maurer, D. S. Lambrecht, D. Flaig, and C. Ochsenfeld, J. Chem. Phys. 136, 144107 (2012)10.1063/1.3693908], which exploits the asympotic decay of the integral values with increasing bra-ket separation as deduced from the multipole expansion and combines this decay behavior with the common Schwarz bound to a tight and simple estimate. We demonstrate on a diverse selection of benchmark systems that our AO-MP2 method in combination with the QQR-type estimates produces reliable results for systems with both localized and delocalized electronic structure, while in the latter case the screening essentially reverts to the common Schwarz screening. For systems with localized electronic structure, our AO-MP2 method shows an early onset of linear scaling as demonstrated on DNA systems. The favorable scaling behavior allows to compute systems with more than 1000 atoms and 10 000 basis functions on a single core that are clearly not accessible with conventional MP2 methods. Furthermore, our AO-MP2 method is particularly suited for parallelization and we present benchmark calculations on a protein-DNA repair complex comprising 2025 atoms and 20 371 basis functions.
Static correlations functions and domain walls in glass-forming liquids: The case of a sandwich geometry
Authors: Gradenigo Giacomo , Trozzo Roberto , Cavagna Andrea , Grigera Tomás S. , Verrocchio Paolo
Published: January 2013

The problem of measuring nontrivial static correlations in deeply supercooled liquids made recently some progress thanks to the introduction of amorphous boundary conditions, in which a set of free particles is subject to the effect of a different set of particles frozen into their (low temperature) equilibrium positions. In this way, one can study the crossover from nonergodic to ergodic phase, as the size of the free region grows and the effect of the confinement fades. Such crossover defines the so-called point-to-set correlation length, which has been measured in a spherical geometry, or cavity. Here, we make further progress in the study of correlations under amorphous boundary conditions by analyzing the equilibrium properties of a glass-forming liquid, confined in a planar (“sandwich”) geometry. The mobile particles are subject to amorphous boundary conditions with the particles in the surrounding walls frozen into their low temperature equilibrium configurations. Compared to the cavity, the sandwich geometry has three main advantages: (i) the width of the sandwich is decoupled from its longitudinal size, making the thermodynamic limit possible; (ii) for very large width, the behaviour off a single wall can be studied; (iii) we can use “anti-parallel” boundary conditions to force a domain wall and measure its excess energy. Our results confirm that amorphous boundary conditions are indeed a very useful new tool in the study of static properties of glass-forming liquids, but also raise some warning about the fact that not all correlation functions that can be calculated in this framework give the same qualitative results.
On twistor transformations and invariant differential operator of simple Lie group G2(2)
Authors: Wang Wei
Published: January 2013

The twistor transformations associated to the simple Lie group G2 are described explicitly. We consider the double fibration \documentclass[12pt]{minimal}\begin{document}${\rm G}_2/P_2 \xleftarrow {\eta } {{\rm G}_2/B} \xrightarrow {\tau }{\rm G}_2/P_1$\end{document}G2/P2←ηG2/B→τG2/P1, where P1 and P2 are two parabolic subgroups of G2 and B is a Borel subgroup, and its local version: \documentclass[12pt]{minimal}\begin{document}$\mathcal {H}^*_2 \xleftarrow {\eta } \mathcal {F} \xrightarrow {\tau } \mathcal {H}_1$\end{document}H2*←ηF→τH1, where \documentclass[12pt]{minimal}\begin{document}$\mathcal {H}_1$\end{document}H1 is the Heisenberg group of dimension 5 embedded in the coset space G2/P1, \documentclass[12pt]{minimal}\begin{document}$\mathcal {F} = \mathbb {CP}^1 \times \mathcal {H}_1$\end{document}F=CP1×H1 and \documentclass[12pt]{minimal}\begin{document}$\mathcal {H}^*_2$\end{document}H2* contains the nilpotent Lie group \documentclass[12pt]{minimal}\begin{document}$\mathcal {H}_2$\end{document}H2 of step three. The Baker-Campbell-Hausdorff formula is used to parametrize the coset spaces, coordinates charts, their transition functions and the fibers of the projection η as complex curves. We write down the relative De-Rham sequence on \documentclass[12pt]{minimal}\begin{document}$\mathcal {F}$\end{document}F along the fibers and push it down to \documentclass[12pt]{minimal}\begin{document}$\mathcal {H}_1$\end{document}H1 to get a family of matrix-valued differential operators \documentclass[12pt]{minimal}\begin{document}${\mathscr D}_k$\end{document}Dk. Then we establish a kind of Penrose correspondence for G2: the kernel of \documentclass[12pt]{minimal}\begin{document}$\mathscr{D}_k$\end{document}Dk is isomorphic to the first cohomology of the sheaf \documentclass[12pt]{minimal}\begin{document}$\mathscr{O} (-k )$\end{document}O(−k) over \documentclass[12pt]{minimal}\begin{document}$\mathcal {H}^*_2$\end{document}H2*. We also give the Penrose-type integral transformation u = Pf for \documentclass[12pt]{minimal}\begin{document}$f\in \mathscr{O} (-k )$\end{document}f∈O(−k), which gives solutions to equations \documentclass[12pt]{minimal}\begin{document}${\mathscr D}_ku=0$\end{document}Dku=0. When restricted to the real Heisenberg group, the differential operators are invariant under the action of G2(2). Exchanging P1 and P2, we derive corresponding results on \documentclass[12pt]{minimal}\begin{document}$\mathcal {H}_2$\end{document}H2.
Origin of recoil hysteresis in nanocomposite Pr8Fe87B5 magnets
Authors: Li Z. B. , Shen B. G. , Sun J. R.
Published: January 2013

The physical mechanism of recoil hysteresis loops has been subject to dispute in recent years. This paper deals with the origin of recoil hysteresis in nanocomposite Pr8Fe87B5 magnets. It is shown by investigating the recoil loops and magnetic activation of melt-spun ribbon of Pr8Fe87B5 at different temperatures that the openness of recoil hysteresis loops is strongly dependent on the magnetic activation as the negative field (opposite to magnetization) is cycled to zero in a remanent state. The hysteresis of recoil loops originates from the reversible magnetization reversal of hard phase, which is probably caused by the energy of isotropic exchange coupling overcoming the energy barrier of magnetocrystalline anisotropy. So, the hysteresis is codetermined by the exchange coupling and variation of anisotropy, thus the openness has a linear relationship with the product of magnetic moments of activation and reversible susceptibility.
Enhanced anisotropic heat conduction in multi-walled carbon nanotubes
Authors: Hayashi Hiroyuki , Ikuta Tatsuya , Nishiyama Takashi , Takahashi Koji
Published: January 2013

Anisotropy of heat conduction in multi-walled carbon nanotubes (MWNTs) is investigated by measuring heat flows in a pristine MWNT and in a MWNT with defects. The in- and out-of-shell thermal conductivities of each MWNT graphite shell are determined, and differences of more than four orders of magnitude are obtained because of the inter-shell gaps. This enhanced anisotropy reduces the conductance by 74% compared with that of the pristine MWNT because of the presence of outer shell defects, which comprise only 2.8% volume ratio. Furthermore, the anisotropy-assisted length dependence of thermal conductivity is demonstrated, even though there is no ballistic phonon transport.
Chemical bonds and vibrational properties of ordered (U, Np, Pu) mixed oxides
Authors: Yang Yu , Zhang Ping
Published: January 2013

We use density functional theory +U to investigate the chemical bonding characters and vibrational properties of the ordered (U, Np, Pu) mixed oxides (MOXs), UNpO4, NpPuO4, and UPuO4. It is found that the 5f electronic states of different actinide elements keep their localized characters in all three MOXs. The occupied 5f electronic states of different actinide elements do not overlap with each other and tend to distribute over the energy band gap of the other actinide element's 5f states. As a result, the three ordered MOXs all show smaller band gaps than those of the component dioxides, with values of 0.91, 1.47, and 0.19 eV for UNpO4, NpPuO4, and UPuO4, respectively. Through careful charge density analysis, we further show that the U-O and Pu-O bonds in MOXs show more ionic character than in UO2 and PuO2, while the Np-O bonds show more covalent character than in NpO2. The change in covalencies in the chemical bonds leads to vibrational frequencies of oxygen atoms that are different in MOXs.
High performance CMOS-like inverter based on an ambipolar organic semiconductor and low cost metals
Authors: Zeng Wei-Jing , Zhou Xing-Yu , Pan Xiao-Jun , Song Cheng-Li , Zhang Hao-Li
Published: January 2013

We report the fabrication of simply structured and high performance organic complementary inverters based on an ambipolar organic semiconductor, 8,9,10,11-tetrachloro-6,13-bis-(triisopropylsilylethynyl)-1-azapentacene (4Cl-Azapen). Individual transistors using symmetric Au electrodes showed high and balanced performance, with good hole (up to 0.23 cm2V−1s−1) and electron (up to 0.21 cm2V−1s−1) mobilities. Integrated complementary inverters showed sharp inversions with high gains (>180) and negligible hysteresis. The inverters using low-cost electrodes, Ag and Cu, also exhibited high gains and high noise margins (>75% of the ideal value).
The Scintillating Grid Illusion is Enhanced by Binocular Viewing
Authors: Read Jenny C. A. , Robson Joseph H. , Smith Christopher L. , Lucas Andrew D.
Published: January 2013

The scintillating grid illusion is an intriguing stimulus consisting of a grey grid on a black background, with white discs at the grid intersections. Most viewers perceive illusory “scintillating” black discs within the physical white discs, especially at non-fixated locations. Here, we report for the first time that this scintillation percept is stronger when the stimulus is viewed binocularly than when it is presented to only one eye. Further experiments indicate that this is not simply because two monocular percepts combine linearly, but involves a specifically cyclopean contribution (Schrauf & Spillmann, 2000). However, the scintillation percept does not depend on the absolute disparity of the stimulus relative to the screen. In an intriguing twist, although the basic illusion shows more scintillation when viewed binocularly, when the illusion is weakened by shifting the discs away from the grid intersections, scintillation becomes stronger with monocular viewing.
Marr's Vision 30 Years on: From a Personal Point of View
Authors: Quinlan Philip
Published: January 2013

This preface provides a personal reflection on the work of Marr and a commentary on the nature of the Special Issue. Although this is in the main an opinion piece, particular mention is made of Marr's earlier work on brain function and how this may inform thinking about Bayesian approaches to vision.
Dividing a Fixed Portion into More Pieces Leads to Larger Portion Size Estimates of JELL-O® Squares
Authors: Scisco Jenna L , Blades Charlene , Zielinski Melissa J , Muth Eric R
Published: January 2013

How visual qualities of a food impact perceptions of the amount of food present and consumed have been studied. Previous research has investigated many factors affecting these perceptions, including the height of a glass, the size of a serving bowl, and other food intake cues. We investigated how the number of pieces a serving is divided into impacts perceptions of the amount of food present and consumed. Results indicate that dividing a fixed portion into a greater number of pieces leads people to perceive a greater amount of food in the serving.
Are People Adapted to Their Own Glasses?
Authors: Schot Willemijn D , Brenner Eli , Sousa Rita , Smeets Jeroen B J
Published: January 2013

Negative lenses, either in the form of glasses or contact lenses, can correct nearsightedness. Unlike contact lenses, glasses do not only correct, but also induce optic distortions. In the scientific literature, it has often been assumed that people who wear corrective glasses instantaneously account for these distortions when they put their glasses on. We tested this assumption and found that, when people switched between their contact lenses and their glasses, they made the errors that one would predict based on the optics. This shows that people are not immediately adapted to their own glasses when they put them on.
Wheatstone and the Origins of Moving Stereoscopic Images
Authors: Wade Nicholas J
Published: January 2013

The recent resurgence of stereoscopic films and television programmes occasions reflection on their origins. Experimental studies of stroboscopic (apparent) motion and stereoscopic vision have their origins in London in the decade from 1825 to 1835. Instruments were devised which simulated motion and depth: sequences of still images could appear to move, and paired pictures (with small horizontal disparities and presented to different eyes) were seen in depth. Until that time, the experience of motion was almost always a consequence of object or observer movement: apparent motion was a novelty. By contrast, stereoscopic vision was the near-universal experience of using two eyes in the natural environment, but its basis remained mysterious. The stereoscope rendered the normal conditions for seeing depth from disparity experimentally tractable. The instruments were called philosophical toys because they fulfilled the dual roles of furthering scientific experiment on the senses and of providing popular amusement. The investigations were initially driven by the need for stimulus control so that the methods of physics could be applied to the study of perceptual phenomena. Many varieties of stroboscopic discs and stereoscopes were devised thereafter and their popularity increased enormously after 1840, when combined with photography. Presenting sequences of stereoscopic photographs in apparent motion was attempted in the 1850s, but proved less successful. The catalyst involved in all these developments was Charles Wheatstone.
Language as a Source of Evidence for Theories of Spatial Representation
Authors: Jackendoff Ray
Published: January 2013

David Marr's metatheory emphasized the importance of what he called the computational level of description—an analysis of the task the visual system performs. In the present article I argue that this task should be conceived of not just as object recognition but as spatial understanding, and that the mental representations responsible for spatial understanding are not exclusively visual in nature. In particular, a theory of the visual system must interact with a theory of the language faculty to explain how we talk about what we see—and how we see all the things we talk about as though they are part of the perceived world. An examination of spatial language both raises the bar for theories of vision and provides important hints for how spatial understanding is structured.
Vision, Reanimated and Reimagined
Authors: Edelman Shimon
Published: January 2013

The publication in 1982 of David Marr's Vision has delivered a singular boost and a course correction to the science of vision. Thirty years later, cognitive science is being transformed by the new ways of thinking about what it is that the brain computes, how it does that, and, most importantly, why cognition requires these computations and not others. This ongoing process still owes much of its impetus and direction to the sound methodology, engaging style, and unique voice of Marr's Vision.
Is Size Misperception of Targets Simply Justification for Poor Performance?
Authors: Wesp Richard , Gasper John
Published: January 2013

Recent studies show that those who perform poorly on sporting activities involving targets recall the target as smaller than do better performers. Some have attributed the effect to action-specific perception, suggesting perception is influenced directly by how one interacts with an object. We proposed that underestimation of target size may instead serve as a justification for poor performance. We found that inaccurate dart throwers, given an excuse that the darts were of poor quality, were less likely to recall the target as smaller. The findings extend research indicating that perception is influenced by motivational factors, and provide further evidence that size estimates can be distorted by memory errors.
Vision and Sketching
Authors: Forbus Kenneth D
Published: January 2013

This essay reflects on the revolution David Marr brought about in vision research, and in cognitive science more broadly. I start with an insider's view, then examine the methodological impact of his framework in cognitive science in general. My group's work on sketch understanding descends from Marr's approach to vision, a connection which I make to provide a concrete illustration. I close with a few thoughts about how research in vision and other areas of cognitive science might come together in the future.
Does This Computational Theory Solve the Right Problem? Marr, Gibson, and the Goal of Vision
Authors: Warren William H
Published: January 2013

David Marr's book Vision attempted to formulate a thoroughgoing formal theory of perception. Marr borrowed much of the “computational” level from James Gibson: a proper understanding of the goal of vision, the natural constraints, and the available information are prerequisite to describing the processes and mechanisms by which the goal is achieved. Yet, as a research program leading to a computational model of human vision, Marr's program did not succeed. This article asks why, using the perception of 3D shape as a morality tale. Marr presumed that the goal of vision is to recover a general-purpose Euclidean description of the world, which can be deployed for any task or action. On this formulation, vision is underdetermined by information, which in turn necessitates auxiliary assumptions to solve the problem. But Marr's assumptions did not actually reflect natural constraints, and consequently the solutions were not robust. We now know that humans do not in fact recover Euclidean structure—rather, they reliably perceive qualitative shape (hills, dales, courses, ridges), which is specified by the second-order differential structure of images. By recasting the goals of vision in terms of our perceptual competencies, and doing the hard work of analyzing the information available under ecological constraints, we can reformulate the problem so that perception is determined by information and prior knowledge is unnecessary.
The Ghost of Helioth and His Stereoscope: The Return of a Phantom
Authors: Wade Nicholas J
Published: January 2013

Among the myths surrounding the invention of the stereoscope, that of Helioth stands as a supreme example of shoddy scholarship and its subsequent dissemination. Helioth was said to have made a simple stereoscope before Wheatstone presented his mirror stereoscope to the public in 1838. There is no evidence of Helioth's existence prior to a report in the mid-twentieth century, and despite attempts to dispel his ghost it has recently resurfaced.
Small molecule targeting Cdc42–intersectin interaction disrupts Golgi organization and suppresses cell motility
Authors: Friesland Amy , Zhao Yaxue , Chen Yan-Hua , Wang Lie , Zhou Huchen , Lu Qun
Published: January 2013

Signaling through the Rho family of small GTPases has been intensely investigated for its crucial roles in a wide variety of human diseases. Although RhoA and Rac1 signaling pathways are frequently exploited with the aid of effective small molecule modulators, studies of the Cdc42 subclass have lagged because of a lack of such means. We have applied high-throughput
in silico
screening and identified compounds that are able to fit into the surface groove of Cdc42, which is critical for guanine nucleotide exchange factor binding. Based on the interaction between Cdc42 and intersectin (ITSN), a specific Cdc42 guanine nucleotide exchange factor, we discovered compounds that rendered ITSN-like interactions in the binding pocket. By using in vitro binding and imaging as well as biochemical and cell-based assays, we demonstrated that ZCL278 has emerged as a selective Cdc42 small molecule modulator that directly binds to Cdc42 and inhibits its functions. In Swiss 3T3 fibroblast cultures, ZCL278 abolished microspike formation and disrupted GM130-docked Golgi structures, two of the most prominent Cdc42-mediated subcellular events. ZCL278 reduces the perinuclear accumulation of active Cdc42 in contrast to NSC23766, a selective Rac inhibitor. ZCL278 suppresses Cdc42-mediated neuronal branching and growth cone dynamics as well as actin-based motility and migration in a metastatic prostate cancer cell line (i.e., PC-3) without disrupting cell viability. Thus, ZCL278 is a small molecule that specifically targets Cdc42–ITSN interaction and inhibits Cdc42-mediated cellular processes, thus providing a powerful tool for research of Cdc42 subclass of Rho GTPases in human pathogenesis, such as those of cancer and neurological disorders.
Droplet microfluidics driven by gradients of confinement
Authors: Dangla Rémi , Kayi S. Cagri , Baroud Charles N.
Published: January 2013

The miniaturization of droplet manipulation methods has led to drops being proposed as microreactors in many applications of biology and chemistry. In parallel, microfluidic methods have been applied to generate monodisperse emulsions for applications in the pharmaceuticals, cosmetics, and food industries. To date, microfluidic droplet production has been dominated by a few designs that use hydrodynamic forces, resulting from the flowing fluids, to break drops at a junction. Here we present a platform for droplet generation and manipulation that does not depend on the fluid flows. Instead, we use devices that incorporate height variations to subject the immiscible interfaces to gradients of confinement. The resulting curvature imbalance along the interface causes the detachment of monodisperse droplets, without the need for a flow of the external phase. Once detached, the drops are self-propelled due to the gradient of surface energy. We show that the size of the drops is determined by the device geometry; it is insensitive to the physical fluid properties and depends very weakly on the flow rate of the dispersed phase. This allows us to propose a geometric theoretical model that predicts the dependence of droplet size on the geometric parameters, which is in agreement with experimental measurements. The approach presented here can be applied in a wide range of standard applications, while simplifying the device operations. We demonstrate examples for single-droplet operations and high-throughput generation of emulsions, all of which are performed in simple and inexpensive devices.
Slk19 clusters kinetochores and facilitates chromosome bipolar attachment
Authors: Richmond Daniel , Rizkallah Raed , Liang Fengshan , Hurt Myra M. , Wang Yanchang
Published: January 2013

In all eukaryotic cells, DNA is packaged into multiple chromosomes that are linked to microtubules through a large protein complex called a kinetochore. Previous data show that the kinetochores are clustered together during most of the cell cycle, but the mechanism and the biological significance of kinetochore clustering are unknown. As a kinetochore protein in budding yeast, the role of Slk19 in the stability of the anaphase spindle has been well studied, but its function in chromosome segregation has remained elusive. Here we show that Slk19 is required for kinetochore clustering when yeast cells are treated with the microtubule-depolymerizing agent nocodazole. We further find that slk19Δ mutant cells exhibit delayed kinetochore capture and chromosome bipolar attachment after the disruption of the kinetochore–microtubule interaction by nocodazole, which is likely attributed to defective kinetochore clustering. In addition, we show that Slk19 interacts with itself, suggesting that the dimerization of Slk19 may mediate the interaction between kinetochores for clustering. Therefore Slk19 likely acts as kinetochore glue that clusters kinetochores to facilitate efficient and faithful chromosome segregation.
Fis1, Mff, MiD49, and MiD51 mediate Drp1 recruitment in mitochondrial fission
Authors: Losón Oliver C. , Song Zhiyin , Chen Hsiuchen , Chan David C.
Published: January 2013

Several mitochondrial outer membrane proteins—mitochondrial fission protein 1 (Fis1), mitochondrial fission factor (Mff), mitochondrial dynamics proteins of 49 and 51 kDa (MiD49 and MiD51, respectively)—have been proposed to promote mitochondrial fission by recruiting the GTPase dynamin-related protein 1 (Drp1), but fundamental issues remain concerning their function. A recent study supported such a role for Mff but not for Fis1. In addition, it is unclear whether MiD49 and MiD51 activate or inhibit fission, because their overexpression causes extensive mitochondrial elongation. It is also unknown whether these proteins can act in the absence of one another to mediate fission. Using Fis1-null, Mff-null, and Fis1/Mff-null cells, we show that both Fis1 and Mff have roles in mitochondrial fission. Moreover, immunofluorescence analysis of Drp1 suggests that Fis1 and Mff are important for the number and size of Drp1 puncta on mitochondria. Finally, we find that either MiD49 or MiD51 can mediate Drp1 recruitment and mitochondrial fission in the absence of Fis1 and Mff. These results demonstrate that multiple receptors can recruit Drp1 to mediate mitochondrial fission.