bluuebunny/crossref_metadata_2025 huggingface dataset:
Introduction to the 26th international conference on logic programming special issue
Authors: HERMENEGILDO MANUEL , SCHAUB TORSTEN
Published: July 2010

The Logic Programming (LP) community, through the Association for Logic Programming (ALP) and its Executive Committee, decided to introduce for 2010 important changes in the way the main yearly results in LP and related areas are published. Whereas such results have appeared to date in standalone volumes of proceedings of the yearly International Conferences on Logic Programming (ICLP), and this method—fully in the tradition of Computer Science (CS)—has served the community well, it was felt that an effort needed to be made to achieve a higher level of compatibility with the publishing mechanisms of other fields outside CS.
Automated termination analysis for logic programs with cut
Authors: SCHNEIDER-KAMP PETER , GIESL JÜRGEN , STRÖDER THOMAS , SEREBRENIK ALEXANDER , THIEMANN RENÉ
Published: July 2010

Termination is an important and well-studied property for logic programs. However, almost all approaches for automated termination analysis focus on definite logic programs, whereas real-world Prolog programs typically use the cut operator. We introduce a novel pre-processing method which automatically transforms Prolog programs into logic programs without cuts, where termination of the cut-free program implies termination of the original program. Hence after this pre-processing, any technique for proving termination of definite logic programs can be applied. We implemented this pre-processing in our termination prover AProVE and evaluated it successfully with extensive experiments.
Swapping evaluation: A memory-scalable solution for answer-on-demand tabling
Authors: DE GUZM'AN PABLO CHICO , CARRO MANUEL , WARREN DAVID S.
Published: July 2010

One of the differences among the various approaches to suspension-based tabled evaluation is the scheduling strategy. The two most popular strategies arelocalandbatchedevaluation. The former collects all the solutions to a tabled predicate before making any one of them available outside the tabled computation. The latter returns answers one by one before computing them all, which in principle is better if only one answer (or a subset of the answers) is desired. Batched evaluation is closer to SLD evaluation in that it computes solutions lazily as they are demanded, but it may need arbitrarily more memory than local evaluation, which is able to reclaim memory sooner. Some programs which in practice can be executed under the local strategy quickly run out of memory under batched evaluation. This has led to the general adoption of local evaluation at the expense of the more depth-first batched strategy. In this paper we study the reasons for the high memory consumption of batched evaluation and propose a new scheduling strategy which we have termedswapping evaluation. Swapping evaluation also returns answers one by one before completing a tabled call, but its memory usage can be orders of magnitude less than batched evaluation. An experimental implementation in the XSB system shows that swapping evaluation is a feasible memory-scalable strategy that need not compromise execution speed.
Inference with constrained hidden Markov models in PRISM
Authors: CHRISTIANSEN HENNING , HAVE CHRISTIAN THEIL , LASSEN OLE TORP , PETIT MATTHIEU
Published: July 2010

A Hidden Markov Model (HMM) is a common statistical model which is widely used for analysis of biological sequence data and other sequential phenomena. In the present paper we show how HMMs can be extended with side-constraints and present constraint solving techniques for efficient inference. Defining HMMs with side-constraints in Constraint Logic Programming has advantages in terms of more compact expression and pruning opportunities during inference. We present a PRISM-based framework for extending HMMs with side-constraints and show how well-known constraints such as cardinality and all_different are integrated. We experimentally validate our approach on the biologically motivated problem of global pairwise alignment.
A translational approach to constraint answer set solving
Authors: DRESCHER CHRISTIAN , WALSH TOBY
Published: July 2010

We present a new approach to enhancing Answer Set Programming (ASP) with Constraint Processing techniques which allows for solving interesting Constraint Satisfaction Problems in ASP. We show how constraints on finite domains can be decomposed into logic programs such that unit-propagation achieves arc, bound or range consistency. Experiments with our encodings demonstrate their computational impact.
Catching the Ouroboros: On debugging non-ground answer-set programs
Authors: OETSCH JOHANNES , PÜHRER JÖRG , TOMPITS HANS
Published: July 2010

An important issue towards a broader acceptance of answer-set programming (ASP) is the deployment of tools which support the programmer during the coding phase. In particular, methods fordebuggingan answer-set program are recognised as a crucial step in this regard. Initial work on debugging in ASP mainly focused on propositional programs, yet practical debuggers need to handle programs with variables as well. In this paper, we discuss a debugging technique that is directly geared towards non-ground programs. Following previous work, we address the central debugging question why some interpretation is not an answer set. The explanations provided by our method are computed by means of a meta-programming technique, using a uniform encoding of a debugging request in terms of ASP itself. Our method also permits programs containing comparison predicates and integer arithmetics, thus covering a relevant language class commonly supported by all state-of-the-art ASP solvers.
Testing and debugging techniques for answer set solver development
Authors: BRUMMAYER ROBERT , JÄRVISALO MATTI
Published: July 2010

This paper develops automated testing and debugging techniques for answer set solver development. We describe a flexible grammar-based black-box ASP fuzz testing tool which is able to reveal various defects such as unsound and incomplete behavior, i.e. invalid answer sets and inability to find existing solutions, in state-of-the-art answer set solver implementations. Moreover, we develop delta debugging techniques for shrinking failure-inducing inputs on which solvers exhibit defective behavior. In particular, we develop a delta debugging algorithm in the context of answer set solving, and evaluate two different elimination strategies for the algorithm.
Anisotropy of magnetic susceptibility fabrics in syntectonic plutons as tectonic strain markers: the example of the Canso pluton, Meguma Terrane, Nova Scotia
Authors: Benn Keith
Published: July 2010

The anisotropy of magnetic susceptibility (AMS) is widely and routinely used to measure the preferred orientations of Fe-rich minerals in undeformed and weakly deformed granite plutons. The interpretation of the mapped AMS fabrics depends on rock-textural observations, on the map patterns of the fabrics in plutons, and on comparisons of the pluton fabrics to tectonic structures in the country rocks. The AMS may document emplacement-flow related fabrics, but the emplacement fabrics may be reworked or completely overprinted by rather weak tectonic strains of the magma mush or the cooling pluton, especially in syntectonic intrusions. The Late Devonian Canso granite pluton is an excellent example of overprinting of emplacement fabrics by weak tectonic strains. The Canso pluton was emplaced ca. 370 Ma along the boundary between the Meguma and Avalon tectonic terranes, in the northern Appalachian orogen. The AMS was mapped along two traverses that cross the pluton and that are perpendicular to the terrane boundary. Textural evidence suggests the rocks underwent very modest post-full crystallisation strains. The AMS records the dextral transcurrent shearing that occurred on the terrane boundary during emplacement and cooling of the Canso pluton, supporting interpretations that weakly deformed syntectonic granites can be used as indicators of regional bulk kinematics. AMS fabrics in Late Devonian granites of the Meguma Terrane suggest partitioning of the non-coaxial shearing into the terrane bounding fault, with pure-shear dominated deformation further from the fault. Numerical simulations suggest that the kinematics recorded by the fabrics in the Canso pluton was simple-shear, or transpression or transpression with small components of pure shear oriented perpendicular to the bounding shear zone.
Granite formation: Stepwise accumulation of melt or connected networks?
Authors: Bons Paul D. , Becker Jens K. , Elburg Marlina A. , Urtson Kristjan
Published: July 2010

Several authors have proposed that granitic melt accumulation and transport from the source region occurs in networks of connected melt-filled veins and dykes. These models envisage the smallest leucosomes as ‘rivulets’ that connect to feed larger dykes that form the ‘rivers’ through which magma ascends through the sub-solidus crust. This paper critically reviews this ‘rivulets-feeding-rivers’ model. It is argued that such melt-filled networks are unlikely to develop in nature, because melt flows and accumulates well before a fully connected network can be established. In the alternative stepwise accumulation model, flow and accumulation is transient in both space and time. Observations on migmatites at Port Navalo, France, that were used to support the existence of melt-filled networks are discussed and reinterpreted. In this interpretation, the structures in these migmatites are consistent with the collapse and draining of individual melt batches, supporting the stepwise accumulation model.
Trace element constraints on mid-crustal partial melting processes – A garnet ionprobe study from polyphase migmatites (Damara orogen, Namibia)
Authors: Jung C. , Jung S. , Hellebrand E. , Hoffer E.
Published: July 2010

Trace element abundances in garnet from a polyphase migmatite were measured by secondary ion mass spectrometry (SIMS) in order to identify some of the effective variables on the trace element distribution between garnet and melanosome or leucosome. In general, garnet is zoned with respect to REE, in which garnet cores are enriched by a factor of 2–3 relative to the rims. For an inclusion-rich garnet from the melanosome, equilibrium distribution following a simple Rayleigh fractionation is responsible for the decreasing concentrations in REE from core to rim. Inclusion-poor garnet from the same melanosome located in the vicinity of the leucosomes shows distinct enrichment and depletion patterns for REE from core to rim. These features suggest disequilibrium between garnet and the host rock which, in this case, could have been an in-situ derived melt. This would probably indicate a period of open-system behaviour at a time when the garnet, originally nucleated in the metamorphic environment reacted with the melt. In addition, non-gradual variation in trace element abundances between core and rim may suggest variable garnet growth rates. Inclusion-free garnet from the leucosome, interpreted to have crystallised in the presence of a melt, has a small core with high REE abundances and a broad rim with lower REE abundances. Here, crystal-liquid diffusion-controlled partitioning is a likely process to explain the trace element variation.
Plutonism versus Neptunism at the southern tip of Africa: the debate on the origin of granites at the Cape, 1776–1844
Authors: Master Sharad
Published: July 2010

The Cape Granites are a granitic suite intruded into Neoproterozoic greywackes and slates, and unconformably overlain by early Palaeozoic Table Mountain Group orthoquartzites. They were first recognised at Paarl in 1776 by Francis Masson, and by William Anderson and William Hamilton in 1778. Studies of the Cape Granites were central to some of the early debates between the Wernerian Neptunists (Robert Jameson and his former pupils) and the Huttonian Plutonists (John Playfair, Basil Hall, Charles Darwin), in the first decades of the 19th Century, since it is at the foot of Table Mountain that the first intrusive granites outside of Scotland were described by Hall in 1812. The Neptunists believed that all rocks, including granite and basalt, were precipitated from the primordial oceans, whereas the Plutonists believed in the intrusive origin of some igneous rocks, such as granite. In this paper, some of the early descriptions and debates concerning the Cape Granites are reviewed, and the history of the development of ideas on granites (as well as on contact metamorphism and sea level changes) at the Cape in the late 18th Century and early to mid 19th Century, during the emerging years of the discipline of geology, is presented for the first time.
Gait Disorders and Falls
Authors: Gschwind Yves J. , Bridenbaugh Stephanie A. , Kressig Reto W.
Published: July 2010

Since approximately 30% of persons over the age of 65 fall each year, prevention of falls is a very important topic. Gait disorders and diminished ability to walk safely are associated with an increased risk of falling. In older adults, falls commonly lead to injuries, institutionalization, and early death. The resultant decline in activities of daily living further contributes to loss of mobility and independence. Gait analysis using the dual-task paradigm (e.g., walking and carrying a cup of tea) offers a sensible tool for detecting older persons prone to falling. Changes in gait patterns due to simultaneously performing a secondary attention-demanding task are interpreted as interference by competing demands for attentional resources in gait control. Exercise interventions such as Jaques-Dalcroze eurhythmics address these attentional properties and aim to decrease such interference. To fully stress physical capacities in older adults, not only does automaticity of walking have to be trained, but also simultaneous performance of additional tasks. Exercise interventions for fall prevention should focus on developing basic skeletal muscle strength as a prerequisite to training gait automaticity in dual or multiple task situations. Recommendations for further research center on new approaches to combine exercises with additional tasks to improve gait and functionality in older adults.
Ocean tomography with acoustic daylight
Authors: Godin Oleg A. , Zabotin Nikolay A. , Goncharov Valery V.
Published: July 2010

Ambient noise in the ocean provides acoustic illumination, which can be used, similarly to daylight in the atmosphere, to visualize objects and characterize the environment. It has been shown theoretically that deterministic travel times between any two points in a moving or motionless, inhomogeneous, time‐independent medium can be retrieved from the cross‐correlation function of diffuse acoustic noise recorded at the two points, without a detailed knowledge of the noise field's sources or properties. In this paper, techniques are developed to account for receiver motion and suppress contributions due to powerful transient localized noise sources, such as nearby shipping, in order to enhance noise diffusivity. The data‐processing techniques are applied to ambient noise recordings of opportunity, which were obtained as a by‐product of a long‐range sound propagation experiment in the Pacific Ocean. The feasibility of passive ocean acoustic tomography with ambient noise recorded at two vertical line arrays is demonstrated successfully.
Toward defining the autoimmune microbiome for type 1 diabetes
Authors: Giongo Adriana , Gano Kelsey A , Crabb David B , Mukherjee Nabanita , Novelo Luis L , Casella George , Drew Jennifer C , Ilonen Jorma , Knip Mikael , Hyöty Heikki , Veijola Riitta , Simell Tuula , Simell Olli , Neu Josef , Wasserfall Clive H , Schatz Desmond , Atkinson Mark A , Triplett Eric W
Published: July 2010

Several studies have shown that gut bacteria have a role in diabetes in murine models. Specific bacteria have been correlated with the onset of diabetes in a rat model. However, it is unknown whether human intestinal microbes have a role in the development of autoimmunity that often leads to type 1 diabetes (T1D), an autoimmune disorder in which insulin-secreting pancreatic islet cells are destroyed. High-throughput, culture-independent approaches identified bacteria that correlate with the development of T1D-associated autoimmunity in young children who are at high genetic risk for this disorder. The level of bacterial diversity diminishes overtime in these autoimmune subjects relative to that of age-matched, genotype-matched, nonautoimmune individuals. A single species, Bacteroides ovatus, comprised nearly 24% of the total increase in the phylum Bacteroidetes in cases compared with controls. Conversely, another species in controls, represented by the human firmicute strain CO19, represented nearly 20% of the increase in Firmicutes compared with cases overtime. Three lines of evidence are presented that support the notion that, as healthy infants approach the toddler stage, their microbiomes become healthier and more stable, whereas, children who are destined for autoimmunity develop a microbiome that is less diverse and stable. Hence, the autoimmune microbiome for T1D may be distinctly different from that found in healthy children. These data also suggest bacterial markers for the early diagnosis of T1D. In addition, bacteria that negatively correlated with the autoimmune state may prove to be useful in the prevention of autoimmunity development in high-risk children.
Mass Spectrometry Technologies
Authors: Fay Laurent B. , Kussmann Martin
Published: July 2010

In modern nutrition research, mass spectrometry has developed into a tool to assess health, sensory as well as quality and safety aspects of food. Two strategies are followed for nutrient and metabolite analysis either in foodstuffs or in biological fluids sampled from the food consumer:

The “traditional” targeted conception, which measures only selected compounds with pre-determined properties such as a given mass or structure as described later.The more recent non-targeted conception, which includes fingerprinting of samples and evaluating the unidentified signals with statistical methods (e.g., principal component analysis, linear discriminant analysis, discriminant function analysis etc.).

For nutrients and metabolite identification purposes, in addition to NMR, two major techniques are currently applied, namely tandem mass spectrometry and accurate mass measurements. Tandem mass spectrometry enables elucidation and confirmation of metabolite structures, while accurate mass measurements in combination with isotope pattern analysis provide elemental composition of the metabolite. Furthermore, hydrogen/deuterium exchange experiments are combined with mass spectrometry 1 to distinguish between isomeric structures of analytes. On the other hand, quantification of nutrients and metabolites is mostly achieved using the selected-reaction monitoring technique on quadrupole-based platforms. Quadrupole analyzers provide the best linear and dynamic range for biological samples, but application of high-resolution with time-of-flight or Orbitrap analyzers can also separate the signal of interest from interferences thereby enhancing detection limits.

In this chapter, we will focus on a brief description of each mass spectrometric technique applied to nutrition research, with a short emphasis on the working principle of each ionization, mass separation and ion detection method. We will also describe some specific technologies like those enabling detection of stable-isotope labelled macro- and micro-nutrients.
Ecosystem Services
Authors: Gomez Baggethun Erik , Murlis John , White Piran , Thornes John , Azapagic Adisa , Dennis Julian , Norris Ken
Published: July 2010

As human populations grow, so do the resource demands imposed on ecosystems, and the impacts of anthropogenic use and abuse are becoming ever more apparent. This has led to the development of the concept of ecosystem services, which describes the beneficial functions provided by ecosystems for human society. Ecosystem services are limited and hence threatened by over-exploitation, and there is an urgent imperative to evaluate trade-offs between immediate and long-term human needs and to take action to protect biodiversity, which is a key factor in delivering ecosystem services. To help inform decision-makers, economic value is increasingly being associated with many ecosystem services and is often based on the replacement with anthropogenic alternatives. The on-going challenges of maintaining sustainable ecosystems and prescribing economic value to nature is prompting multi-disciplinary shifts in how we recognise and manage the environment. This volume brings together emerging topics in environmental science, making an excellent source for policy makers and environmental consultants working in the field or related areas. Ecosystem Services also serves as a concise and referenced primer for advanced students and researchers in environmental science and management.
Atmospheric Services
Authors: Thornes John
Published: July 2010

The atmosphere is a fundamental component of the Earth System and yet its economic and social value to society, as an essential resource, has largely been taken for granted. Terms such as ‘weather services’, ‘meteorological services’ and ‘climate services’ have existed for some time as part of the commercial and public services offered by national and private meteorological providers. These services are primarily based on providing information about the past, present and future state of the atmosphere rather than its intrinsic properties. The new concept of ‘atmospheric services’, as proposed in this chapter, relates to the inherent set of natural goods and services provided by the atmosphere that enable life, as we know it, to exist and prosper on planet Earth. Twelve basic atmospheric services have been identified (see Table 1) with a Total Economic Value of between 100 and 1000 times the Gross World Product (GWP). Ecosystem Services have been valued at about twice GWP. This analysis shows that the atmosphere is the most precious and valuable of all natural resources in the Earth System. This chapter attempts to justify the valuation of these atmospheric resources and also infers that the atmosphere should be treated as a global commons, and responsibility for its sustainable management should be shared equally amongst all of society. The atmosphere is fragile and at a time of enhanced climate change it requires very careful management and protection. Indeed, a ‘Law of the Atmosphere’ may be required, especially at a time when there is rising interest in the possible future need for geo-engineering the climate on a global scale.
Targeting epigenetic modifiers: Inhibitors of histone methyltransferases
Authors: Bissinger Elisabeth-Maria , Heinke Ralf , Sippl Wolfgang , Jung Manfred
Published: July 2010

Reversible histone methylation is an emerging new target in the field of epigenetic regulation. Here, we review histone methyltransferases in light of their role in disease formation and with regard to the state of the art in drug discovery.
A novel virally inactivated human platelet lysate preparation rich in TGF‐β, EGF and IGF, and depleted of PDGF and VEGF
Authors: Burnouf Pierre‐Alain , Juan Po‐Kai , Su Chen‐Yao , Kuo Ya‐Po , Chou Ming‐Li , Su Ching‐Hua , Tseng Yu‐Hung , Lin Che‐Tong , Burnouf Thierry
Published: July 2010

There is emerging interest in the use of standardized virally inactivated human platelet lysate preparations rich in GFs (growth factors) for cell cultures, cell therapy and clinical applications. In the present paper, we report a simple process to prepare a virally inactivated platelet lysate preparation rich in TGF‐β1 (transforming growth factor‐β1), EGF (epidermal growth factor) and IGF (insulin‐like growth factor) and depleted of PDGF (platelet‐derived growth factor) and VEGF (vascular endothelial growth factor). Apheresis platelet concentrates were treated by the S/D (solvent/detergent) viral inactivation procedure, then subjected to an oil extraction followed by adsorption with activated charcoal and finally sterile‐filtered. The resulting preparation contained a mean of 368.4, 2.4 and 54.7 ng/ml of TGF‐β1, EGF and IGF respectively. PDGF‐AB and VEGF were essentially completely removed by the charcoal treatment. The mean albumin, IgG, IgM and IgA and fibrinogen contents were approx. 40.0, 8.5, 0.87, 1.66 and 2.65 mg/ml respectively, cholesterol and triglycerides were at 15 and 20.7 mg/ml respectively and TnBP (tri‐n‐butyl phosphate) and Triton X‐45 were at 8.7 and 8.8 p.p.m. respectively. Supplementing MEM (minimum essential medium) with 1–10% of this S/D‐treated platelet lysate promoted the proliferation of MG63 and SIRC cell lines as well as, or better than, 10% (v/v) FBS (fetal bovine serum), as based on the MTS [3‐(4,5‐dimethylthiazol‐2‐yl)‐5‐(3‐carboxymethoxyphenyl)‐2‐(4‐sulfophenyl)‐2H‐tetrazolium] assay. The process used to prepare such S/D‐treated platelet lysates is easily scalable for industrial production. Our results open up the possibility to evaluate the potential of this new preparation for stem cell expansion and/or bone tissue engineering and regeneration.
Assessment 360°: A Panoramic Framework for Assessing English Language Learners
Authors: Lewis Nancy , Castilleja Nancy , Moore Barbara J. , Rodriguez Barbara
Published: July 2010

This issue describes the Assessment 360° process, which takes a panoramic approach to the language assessment process with school-age English Language Learners (ELLs). The Assessment 360° process guides clinicians to obtain information from many sources when gathering information about the child and his or her family. To illustrate the process, a bilingual fourth grade student whose native language (L1) is Spanish and who has been referred for a comprehensive language evaluation is presented. This case study features the assessment issues typically encountered by speech-language pathologists and introduces assessment through a panoramic lens. Recommendations specific to the case study are presented along with clinical implications for assessment practices with culturally and linguistically diverse student populations.
The opportunities and challenges of entrepreneurial acquisitions
Authors: Ragozzino Roberto , Reuer Jeffrey J.
Published: July 2010

Abstract Recent research has documented new ventures' activity in acquisitions, and we build upon this work and the mergers and acquisition (M&A) literature in order to compare the acquisition performance of new ventures and established firms. The central rationale for our work is that new ventures hold distinct resources and capabilities that are bound to affect the outcome of their acquisition strategies in unique ways. Thus, from a conceptual standpoint, it is appropriate to isolate the implications of M&A activity by this class of firms, rather than assume that new ventures experience the same M&A performance outcomes as other acquirers. Empirically, our findings support this broad proposition as they indicate that new ventures are more subject to due diligence and valuation problems. However, they also seem to perform better than established firms when acquiring targets with high growth opportunities.
High resolution on-chip thermometry using a microstrip-coupled transition edge sensor
Authors: Goldie D. J. , Rostem K. , Withington S.
Published: July 2010

Our recent work demonstrated highly efficient coupling of broadband thermal photon radiation between the termination resistors of a superconducting microstrip transmission line measured using a transition edge sensor (TES). A simple modification of this scheme is presented that permits rapid thermometry of micron-scale objects at temperatures below 3 K. Broadband photon noise gives a limiting temperature sensitivity of 3.8 μK for a 1 s integration time for measurements at 0.5 K. In practice, phonon noise in the thermal link between the TES and the heat bath limits the achievable temperature resolution to about 30 μK for a typical TES with noise equivalent power of 2×10−17 W/Hz with the same integration time.
Simulations of chemical vapor deposition diamond film growth using a kinetic Monte Carlo model
Authors: May P. W. , Harvey J. N. , Allan N. L. , Richley J. C. , Mankelevich Yu. A.
Published: July 2010

A one-dimensional kinetic Monte Carlo model has been developed to simulate the chemical vapor deposition (CVD) of a diamond (100) surface. The model considers adsorption, etching/desorption, lattice incorporation, and surface migration along and across the dimer rows. The reaction rates for these processes are re-evaluated in detail and their effect upon the predicted growth rates and morphology are described. We find that for standard CVD diamond conditions, etching of sp3 carbon species from the growing surface is negligible. Surface migration occurs rapidly, but is mostly limited to CH2 species oscillating back and forth between two adjacent radical sites. Despite the average number of migration hops being in the thousands, the average surface diffusion length for a surface species—before it either adds to the diamond lattice or is removed back to the gas phase—is <2 sites. β-scission helps to smooth the surface, but is only a relatively minor process removing <2% of adsorbed species. At low substrate temperature, migration is negligible with film growth being dominated by direct adsorption (Eley–Rideal) processes. The resulting films are rough and spiky, reminiscent of amorphous carbon. With increasing substrate temperature migration increases in significance until for temperatures >1000 K migration becomes the major process by which the surface becomes smoother. Langmuir–Hinshelwood processes are now the dominant growth mechanism, although 30% of growth still occurs via direct adsorption.
Local electronic and magnetic studies of an artificial La2FeCrO6 double perovskite
Authors: Gray Benjamin , Lee Ho Nyung , Liu Jian , Chakhalian J. , Freeland J. W.
Published: July 2010

Through the utilization of element-resolved polarized x-ray probes, the electronic and magnetic state of an artificial La2FeCrO6 double perovskite were explored. Applying unit-cell level control of thin film growth on SrTiO3(111), the rock salt double perovskite structure can be created for this system, which does not have an ordered perovskite phase in the bulk. We find that the Fe and Cr are in the proper 3+ valence state, but, contrary to previous studies, the element-resolved magnetic studies find the moments in field are small and show no evidence of sizable magnetic moments in the remanent state. Based on our findings, we argue that the ground state is consistent with canted antiferromagnetic order.
Non-Condon effect on charge transport in dithiophene-tetrathiafulvalene crystal
Authors: Zhang WeiWei , Liang WanZhen , Zhao Yi
Published: July 2010

Combining first-principles calculations and non-Condon charge transfer rates proposed by us recently [Y. Zhao and W. Z. Liang, J. Chem. Phys. 130, 034111 (2009)], we investigated non-Condon effect on charge carrier mobility of organic semiconductor dithiophene-tetrathiafulvalene (DT-TTF) crystal. The first-principles results reveal that only several high-frequency intramolecular vibrational modes dominate the reorganization energy, and the nuclear-coordinate dependence of electronic coupling prefers to perform an exponential or Gaussian property for most intermolecular modes rather than a linear one as assumed in conventional models. Furthermore, the electronic coupling of an isolated DT-TTF dimer is indeed affected by the surrounding molecules. The predicted non-Condon mobilities with use of the obtained structure parameters are always greater than those from Condon approximation, and the non-Condon dynamic disorder is not important for DT-TTF, which is also confirmed by molecular dynamics simulation. More interestingly, the bandlike property can be predicted under the hopping mechanism when the nuclear tunneling is incorporated.
Optical nonlinearities in Si-nanocrystals at 1064 nm excited by nanosecond-pulses
Authors: Martínez A. , Hernández S. , Pellegrino P. , Jambois O. , Garrido B. , Jordana E. , Fedeli J. M.
Published: July 2010

The nonlinear response under nanosecond excitation of Si-nanocrystals embedded in SiO2 has been studied by the z-scan method. A theoretical model, together with an analysis of the behavior under excitation of pulses with variable duration, has revealed the origin of the nonlinearities. The main contribution to the nonlinear optical response has been singled out as coming from free carriers, which are photoexcited by the probed pulses. The free-carrier absorption and free-carrier dispersion of individual Si-nanocrystals at 1064 nm have been estimated from the experimental data, obtaining σabSi-nc=4.3×10−16 cm2 and σrSi-nc=−6.6×10−21 cm3, respectively.
Long exciton spin relaxation in coupled quantum wells
Authors: Kowalik-Seidl K. , Vögele X. P. , Rimpfl B. N. , Manus S. , Kotthaus J. P. , Schuh D. , Wegscheider W. , Holleitner A. W.
Published: July 2010

Spatially indirect excitons in a coupled quantum well structure were studied by means of polarization and time-resolved photoluminescence. A strong degree of circular polarization (>50%) in emission was achieved when the excitation energy was tuned into resonance with the direct exciton state. The indirect transition remained polarized several tens of nanoseconds after the pumping laser pulse, demonstrating directly a very long relaxation time of exciton spin. The observed spin relaxation time exceeds the radiative lifetime of the indirect excitons.
Negative differential resistance in hydrated deoxyribonucleic acid thin films mediated by diffusion-limited water redox reactions
Authors: Lee H.-K. , Jin M. H.-C.
Published: July 2010

dc I-V characteristics of DNA films under variable relative humidity (RH) were obtained showing an exponential increase in current with increasing RH from 20% to 85%. Protonic conduction was signified in details by the presence of a negative differential resistance (NDR) in highly hydrated films. NDR was seen when RH was over ∼70% at which the full coordination of DNA backbone with water molecules was expected. It is concluded that the protonic conduction is originated from water redox reactions and the NDR is the result of the limited diffusion of water on the surface of DNA molecules.
Combination antibody treatment down-regulates epidermal growth factor receptor by inhibiting endosomal recycling
Authors: Spangler Jamie B. , Neil Jason R. , Abramovitch Sivan , Yarden Yosef , White Forest M. , Lauffenburger Douglas A. , Wittrup K. Dane
Published: July 2010

Due to its common dysregulation in epithelial-based cancers and extensive characterization of its role in tumor growth, epidermal growth factor receptor (EGFR) is a highly validated target for anticancer therapies. There has been particular interest in the development of monoclonal antibodies (mAbs) targeting EGFR, resulting in two approved mAb-based drugs and several others in clinical trials. It has recently been reported that treatment with combinations of noncompetitive mAbs can induce receptor clustering, leading to synergistic receptor down-regulation. We elucidate three key aspects of this phenomenon. First, we show that highly potent combinations consisting of two noncompetitive mAbs that target EGFR domain 3 reduce surface receptor levels by up to 80% with a halftime of 0.5–5 h in both normal and transformed human cell lines to an extent inversely proportional to receptor density. Second, we find the mechanism underlying down-regulation to be consistent with recycling inhibition. Third, in contrast to the agonism associated with ligand-induced down-regulation, we demonstrate that mAb-induced down-regulation does not activate EGFR or its downstream effectors and it leads to synergistic reduction in migration and proliferation of cells that secrete autocrine ligand. These new insights will aid in ongoing rational design of EGFR-targeted antibody therapeutics.
Phase behavior of mixtures of human lens proteins Gamma D and Beta B1
Authors: Wang Ying , Lomakin Aleksey , McManus Jennifer J. , Ogun Olutayo , Benedek George B.
Published: July 2010

We have experimentally determined the coexistence surface characterizing the phase behavior of γD-βB1-water ternary solutions. The coexistence surface fully describes the solution conditions, i.e., temperature, protein concentration, and protein composition, at which liquid-liquid phase separation occurs in a ternary solution. We have observed a significant demixing of γD and βB1 i.e., large difference of composition in the two coexisting phases. This demixing suggests that the energy of the γD-βB1 attractive interaction is significantly smaller than the energy of the γD-γD attractive interaction. We also observed the lowering of the phase separation temperature upon increasing of the fraction of βB1 in solution. We provide a theoretical analysis of our experimental data, which enables a quantitative description of our principal experimental findings. In this way, we have evaluated the magnitude and temperature dependence of the relevant interprotein interaction energies. Our findings provide insight into the factors essential for maintaining lens proteins in a single homogeneous phase, thereby enabling lens transparency.
Category induction in autism: Slower, perhaps different, but certainly possible
Authors: Soulières Isabelle , Mottron Laurent , Giguère Gyslain , Larochelle Serge
Published: July 2010

Available studies on categorization in autism indicate possibly intact category formation, performed through atypical processes. Category learning was investigated in 16 high-functioning autistic and 16 IQ-matched nonautistic participants, using a category structure that could generate a conflict between the application of a rule and exemplar memory. Same–different and matching-to-sample tasks allowed us to verify discrimination abilities for the stimuli to be used in category learning. Participants were then trained to distinguish between two categories of imaginary animals, using categorization tests early in the training and at the end (160 trials). A recognition test followed, in order to evaluate explicit exemplar memory. Similar discrimination performance was found in control tasks for both groups. For the categorization task, autistic participants did not use any identifiable strategy early in the training, but used strategies similar to those of the nonautistic participants by the end, with the same level of accuracy. Memory for the exemplars was poor in both groups. Our findings confirm that categorization may be successfully performed by autistics, but may necessitate longer exposure to material, as the top-down use of rules may be only secondary to a guessing strategy in autistics.
Making the illusory correlation effect appear and then disappear: The effects of increased learning
Authors: Murphy Robin A. , Schmeer Stefanie , Vallée-Tourangeau Frédéric , Mondragón Esther , Hilton Denis
Published: July 2010

The acquisition of a negative evaluation of a fictitious minority social group in spite of the absence of any objective correlation between group membership and negative behaviours was described by Hamilton and Gifford (1976) as an instance of an illusory correlation. We studied the acquisition and attenuation through time of this correlation learning effect. In two experiments we asked for participants’ judgements of two fictitious groups using an online version of a group membership belief paradigm. We tested how judgements of the two groups changed as a function of the amount of training they received. Results suggest that the perception of the illusory correlation effect is initially absent, emerges with intermediate amounts of absolute experience, but diminishes and is eliminated with increased experience. This illusory correlation effect can be considered to reflect incomplete learning rather than a bias due to information loss in judgements or distinctiveness.
Single crystal Fe elements patterned by one-step selective chemical wet etching
Authors: Sun Li , Wong Ping Kwan Jonny , Niu Daxin , Zou Xiao , Zhai Ya , Wu Jing , Xu Yongbing , Zhai Hongru
Published: July 2010

A technique has been developed to pattern single crystal ultrathin Fe films by selective chemical wet etching of the Au capping layer and then simultaneous oxidization of the ferromagnetic Fe layer underneath. The focused magneto-optical Kerr effect and ferromagnetic resonance measurements demonstrate that the intrinsic magnetic anisotropy has not been changed in the patterned elements, showing that the chemical bonding at the metal–semiconductor interface remains the same. Further x-ray energy dispersive spectroscopy measurements show that this selective wet-etching technique is suitable for the patterning of thin Fe films with thicknesses less than around 25 ML.
Pressure detector based on the itinerant-electron metamagnetic transition of La(Fe0.88Si0.12)13Hy
Authors: Fujita A , Fujieda S , Fukamichi K , Ohta M
Published: July 2010

The ferromagnetic (FM)–paramagnetic (PM) first-order transition is induced by pressure around room temperature for La(Fe0.88Si0.12)13H1.25 with the Curie temperature T
C = 293 K. The spontaneous magnetization at room temperature is significantly decreased due to the phase transition induced by pressure. In addition, the low-field magnetic susceptibility exhibits a response against hydrostatic pressures. From these results, the pressure detection using FM–PM transition has been demonstrated. By dispersing the coarse-grained La(Fe0.88Si0.12)13H1.25 into a column-shaped epoxy resin, the susceptibility change against the unidirectional stress is detected by the inductance of a coil. The inductance response is scarcely changed after 400 cycles of loading. Relating to endurance, the thermal phase stability of hydrides annealed at various temperatures has been investigated. The hydrogen desorption rate obtained from the Arrhenius plots is negligibly small around room temperature, proving that La(Fe0.88Si0.12)13H1.25 has high thermal phase stability over a long period of time.
Tailoring the magnetoimpedance effect of NiFe/Ag multilayer
Authors: Corrêa M A , Bohn F , Chesman C , da Silva R B , Viegas A D C , Sommer R L
Published: July 2010

The magnetoimpedance (MI) effect was investigated in NiFe/Ag multilayered (ML) and ML/SiO2/Ag/SiO2/ML structured multilayered (SD) ferromagnetic films grown by magnetron sputtering. The MI measurements were performed with an impedance analyzer over a wide frequency range, from 10 MHz to 1.8 GHz. Sample geometries are mainly responsible for the different MI behaviours and by considering the entire frequency range, distinct mechanisms responsible for MI changes were associated. For the ML sample, a maximum value of 80%, associated with the appearance of ferromagnetic resonance (FMR), was reached at around 1 GHz. For the SD sample, the striking feature is the existence of two distinct frequency ranges with high MI% values of 80% at around 100 MHz, related to the skin and magnetoinductive effects, and of 120% at around 1 GHz, associated with the strong skin and FMR effect.
Investigations on the afterglow of a thin cathode discharge in argon at atmospheric pressure
Authors: Mohr Sebastian , Du Beilei , Luggenhölscher Dirk , Czarnetzki Uwe
Published: July 2010

A thin cathode discharge consists of two electrodes separated by a dielectric layer with a thickness of ca 100 µm. The shape of the anode can be chosen arbitrarily, while the thickness of the cathode is also about 100 µm. Through this ‘sandwich’, a hole with a diameter of 200 µm is drilled. When such a device is operated at pressures of several hundred hectopascals, it shows a self-pulsing behaviour in which high electron densities of several 1016 cm−3 are reached. Electrical measurements showed that this can be explained by the repeated ignition of a short-living spark discharge. Due to the high pressure and the related high collision frequencies, the afterglow of this discharge was expected to last several tens of nanoseconds. Instead, lifetimes of several hundred nanoseconds were observed. In order to identify the mechanisms responsible for this long living afterglow, a kinetic model of the afterglow was developed. As a result, Penning ionization, superelastic collisions with both atoms in excited states and excimers were found to play a crucial role in the production and heating of electrons.
Dissecting BAR Domain Function in the Yeast Amphiphysins Rvs161 and Rvs167 during Endocytosis
Authors: Youn Ji-Young , Friesen Helena , Kishimoto Takuma , Henne William M. , Kurat Christoph F. , Ye Wei , Ceccarelli Derek F. , Sicheri Frank , Kohlwein Sepp D. , McMahon Harvey T. , Andrews Brenda J.
Published: July 2010

BAR domains are protein modules that bind to membranes and promote membrane curvature. One type of BAR domain, the N-BAR domain, contains an additional N-terminal amphipathic helix, which contributes to membrane-binding and bending activities. The only known N-BAR-domain proteins in the budding yeast Saccharomyces cerevisiae, Rvs161 and Rvs167, are required for endocytosis. We have explored the mechanism of N-BAR-domain function in the endocytosis process using a combined biochemical and genetic approach. We show that the purified Rvs161–Rvs167 complex binds to liposomes in a curvature-independent manner and promotes tubule formation in vitro. Consistent with the known role of BAR domain polymerization in membrane bending, we found that Rvs167 BAR domains interact with each other at cortical actin patches in vivo. To characterize N-BAR-domain function in endocytosis, we constructed yeast strains harboring changes in conserved residues in the Rvs161 and Rvs167 N-BAR domains. In vivo analysis of the rvs endocytosis mutants suggests that Rvs proteins are initially recruited to sites of endocytosis through their membrane-binding ability. We show that inappropriate regulation of complex sphingolipid and phosphoinositide levels in the membrane can impinge on Rvs function, highlighting the relationship between membrane components and N-BAR-domain proteins in vivo.
Impact of diuretic treatment and sodium intake on plasma volume in patients with compensated systolic heart failure
Authors: Bonfils Peter K. , Damgaard Morten , Taskiran Mustafa , Goetze Jens Peter , Norsk Peter , Gadsbøll Niels
Published: July 2010

Aims

In patients with heart failure (HF), the use of diuretics may be a double‐edged sword that can alleviate symptoms of congestion, but also result in over‐diuresis and intravascular volume depletion. The purpose of the present study was to examine plasma volume (PV) in HF patients receiving from 0 to 160 mg of furosemide and to investigate whether determination of plasma N‐terminal fragment of pro‐brain natriuretic peptide (NT‐proBNP) concentrations can predict PV‐status.

Methods and results

Plasma volume, extracellular volume, glomerular filtration rate, NT‐proBNP, and daily renal sodium excretion were measured in 18 patients with medically treated, compensated HF and in 27 healthy volunteers. Cardiac function was examined by non‐invasive cardiac output determination and echocardiography. Exercise capacity was evaluated by 6 min walk test. There was a borderline significant difference in PV between patients with HF and control subjects (37.3 ± 6.0 and 40.2 ± 5.8 mL/kg, respectively, P = 0.092) with a significant tendency towards a contraction of PV with increasing use of diuretics (P = 0.031). There was no difference in extracellular volume between patients with HF and control subjects (P = 0.844). NT‐proBNP plasma concentrations had no correlation to either sodium excretion (P = 0.193) or PV (P = 0.471) in patients with HF.

Conclusion

Plasma volume in patients with HF was within normal limits, but patients treated with high doses of loop‐diuretics tended to have subnormal PV. Single measurement of NT‐proBNP plasma concentration could not be used to estimate intravascular volume status in patients with HF.