bluuebunny/crossref_metadata_2025 huggingface dataset:
Cortical connections and parallel processing: Structure and function
Authors: Ballard Dana H.
Published: February 2010

The cerebral cortex is a rich and diverse structure that is the basis of intelligent behavior. One of the deepest mysteries of the function of cortex is that neural processing times are only about one hundred times as fast as the fastest response times for complex behavior. At the very least, this would seem to indicate that the cortex does massive amounts of parallel computation.

This paper explores the hypothesis that an important part of the cortex can be modeled as a connectionist computer that is especially suited for parallel problem solving. The connectionist computer uses a special representation, termed value unit encoding, that represents small subsets of parameters in a way that allows parallel access to many different parameter values. This computer can be thought of as computing hierarchies of sensorimotor invariants. The neural substrate can be interpreted as a commitment to data structures and algorithms that compute invariants fast enough to explain the behavioral response times. A detailed consideration of this model has several implications for the underlying anatomy and physiology.
An essay on the circulation as behavior
Authors: Engel Bernard T.
Published: February 2010

Most conceptual models of the organization of the cardiovascular system begin with the premise that the nervous system regulates the metabolic and nonmetabolic reflex adjustments of the circulation. These models assume that all the neurally mediated responses of the circulation are reactive, i.e., reflexes elicited by adequate stimuli. This target article suggests that the responses of the circulation are conditional in three senses. First, as Sherrington argued, reflexes are conditional in that they never operate in a vacuum but in a context together with other reflexes. Guided by functional utility, they interact rather than add. Second, as Pavlov argued, stimuli acquire meanings as a result of experience. This notion of stimulus effect plus the Sherringtonian notion of conditionality suggest that association is one of the ways stimuli eliciting cardiovascular reflexes acquire their meanings and thus their relative strengths. Finally, as Skinner and others have argued, operants are responses that act upon the environment to obtain consequences – that is, stimuli. As operants, cardiovascular responses fulfill a major biological need, functioning proactively. The cardiovascular response is an integral component of the animal's behavior regardless of whether it is an elicited reflex or the eliciting stimulus acquired its properties as a result of the genetic inheritance of the animal or through experience, or the cardiovascular response is emitted in anticipation of an environmental consequence. The main theses of this essay are: (1) behavior is an integrated set of responses and the circulation is one of the response systems comprising behavior; (2) behavior is, in part, determined by its functional significance within a context; (3) the contextual factors operative at the time of the behavior have a major role in determining which of the set of possible responses will determine the final act, that is, which behavior will be the effective response and which other behaviors will be concomitants.
Relationships between the superior colliculus and hippocampus: Neural and behavioral considerations
Authors: Foreman Nigel , Stevens Robin
Published: February 2010

Theories of superior collicular and hippocampal function have remarkable similarities. Both structures have been repeatedly implicated in spatial and attentional behaviour and in inhibitory control of locomotion. Moreover, they share certain electrophysiological properties in their single unit responses and in the synchronous appearance and disappearance of slow wave activity. Both are phylogenetically old and the colliculus projects strongly to brainstem nuclei instrumental in the generation of theta rhythm in the hippocampal EEC

On the other hand, close inspection of behavioural and electrophysiological data reveals disparities. In particular, hippocampal processing mainly concerns stimulus ambiguity, contextual significance, and spatial relations or other subtle, higher order characteristics. This requires the use of largely preprocessed sensory information and mediation of poststimulus investigation. Although collicular activity must also be integrated with that of “higher” centres (probably to a varying degree, depending on the nature of stimuli being processed and the task requirements), its primary role in attention is more “peripheral” and specific in controlling orienting/localisation via eye and body movements toward egocentrically labelled spatial positions. In addition, the colliculus may exert a nonspecific influence in alerting higher centres to the imminence of information potentially worthy of focal attention. Nevertheless, it is noteworthy that collicular and hippocampal lesions produce deficits on similar tasks, although the type of deficit is usually different (often opposite) in each case. Functional overlap between hippocampus and colliculus (i.e., strategically synchronised or mutually interdependent activity) is virtually certain vis-à-vis stimulus sampling, for example in the acquisition of information via vibrissal movements and visual scanning. In addition, insofar as stimulus significance is a factor in collicular orienting mechanisms, the hippocampus — cingulate – cortex — colliculus pathway may play a significant role, modulating collicular responsiveness and thus ensuring an attentional strategy appropriate to current requirements (stimulus familiarity, stage of learning). A tentative “reciprocal loop” model is proposed which bridges physiological and behavioural levels of analysis and which would account for the observed degree and nature of functional overlap between the superior colliculus and hippocampus.
Sensory cortex and the mind-brain problem
Authors: Puccetti Roland , Dykes Robert W.
Published: February 2010

One of the implicit, and sometimes explicit, objectives of modern neuroscience is to find neural correlates of subjective experience so that different qualities of that experience might be explained in detail by reference to the physical structure and processes of the brain. It is generally assumed that such explanations will make unnecessary or rule out any reference to conscious mental agents. This is the classic mind-brain reductivist program. We have chosen to challenge the optimism underlying such an approach in the context of sensory neurophysiology and sensory experience. Specifically, we ask if it is possible to explain the subjective differences among seeing, hearing, and feeling something by inspecting the structure and function of primary visual, auditory, and somesthetic cortex.

After reviewing the progress in localization of sensory functions over the past two centuries and examining some aspects of the structure and function of somesthetic, auditory, and visual cortex, we infer that one cannot explain the subjective differences between sensory modalities in terms of present day neuroscientific knowledge. Nor do present trends in research provide grounds for optimism.

At this point we turn to three philosophical theories to see what promise they hold of explaining these differences. A brief discussion of each – identity theory, functionalism, and eliminative materialism – suggests that none adequately accounts for the facts of the situation, and we tentatively conclude that some form of dualism is still a tenable hypothesis.
Toward a general theory of infantile attachment: a comparative review of aspects of the social bond
Authors: Rajecki D. W. , Lamb Michael E. , Obmascher Pauline
Published: February 2010

This critical appraisal of contemporary interpretations in the area of infantile attachment begins with an outline of the principal features of the Bowlby-Ainsworth ethological theory, the instrumental/operant learning theory of Gewirtz, and Hoffman's classical conditioning model. Some attention is also given to Cairns's contiguity learning analysis and the Hoffman-Solomon opponentprocess model Discussion of these theories is followed by a review of representative data from infants at four phyletic levels (precocial birds, dogs, monkeys, and human beings), with an emphasis on three aspects of social bonding: (a) the formation and persistence of social ties in the infant under conditions of maltreatment, (b) the role of the attachment object in the adjustment of the infant to the broader environment (the so-called secure base effect), and (c) the infant's reaction to involuntary separation from the attachment object.

An attempt is made to judge how well each of the interpretations accounts for all or part of the data, with the conclusion that current theories do not accord completely with documented attachment phenomena. The following criticisms are highlighted: Ethological theory emphasizes that infants' behavior systems have been shaped by the ordinarily expectable environment and depend on that environment for their functioning, yet infants of many species form bonds to objects not typical in any species' environment, or even to sources of maltreatment. Learning theory is faulted for making predictions contradicted by the maltreatment data and for a lack of formal mechanisms to account for the secure base and separation effects. The contiguity analysis is criticized for its inability to account for the emergence of certain response patterns during separation, and the opponent-process model is called into question because of its failure to fit important affective dynamics of social separation (a central focus of this theory). Recommendations for future theories of attachment are offered.
Prospects for a cognitive ethology
Authors: Griffin Donald R.
Published: February 2010

Ethologists and comparative psychologists have found that the social behavior, discrimination learning, and especially the communicative behavior of many animals are sufficiently versatile to call into question the customary denial that animals have mental experiences comparable to our own. Many of their behavior patterns suggest that animals have mental images of objects, events, or relationships remote from the immediate stimulus situation, as well as self-awareness and intentions concerning future actions. Our behavioristicZeitgeisthas inhibited investigation of such possibilities, but reopening these long-neglected questions requires no departure from the materialistic approach to biological and behavioral science. The basic question at issue involves a comparison of those aspects of human and nonhuman brain function that sometimes lead to what we call mental experiences, at least in our own species. It seems more feasible to devise objectively verifiable tests for the existence of these general categories of mental experiences than for that of many others. While many other kinds of evidence could well be used (with appropriate caution and all possible controls) to weigh the likelihood that animals sometimes know what they are doing, the experimental use of communicative behavior seems especially promising, because the latter could serve a function analogous to human language, which provides our best evidence about the mental experiences of our fellow men.
A working-class hero is something to be: the American Musicians’ Union's attempt to ban the Beatles, 1964
Authors: Roberts Michael
Published: February 2010

This article examines the historical and cultural significance of the attempted ban on the Beatles’ concerts in the US by the American Federation of Musicians and the Immigration and Naturalization Service of the United States government in 1964. While there has been much attention given to the court case against John Lennon waged by the INS and the Nixon Administration in the early 1970s, much less is known about the earlier case brought against the Beatles by the INS and the Department of Labor on behalf of the AFM, which became a national scandal in 1964, pitting fans of the Beatles against the AFM and the INS. Fans framed the controversy over the Beatles as a cultural conflict between generations, while the AFM framed the problem as a labour market issue. My examination of the incident reveals the way in which a submerged cultural problem embedded in a putatively economic discourse rose to the surface through conflicts over the discursive framing of the Beatles controversy. This case is important not only in terms of expanding our empirical knowledge of the internal history of the Beatles and rock and roll music, but also more generally as an episode that foreshadowed the cultural conflict between the American labour union bureaucracy and the counter-culture that emerged in the late 1960s. This essay analyses heretofore-unexamined documents from the US National Archives and Records Administration.
Václav Havel and the Expedient Politics of Translation
Authors: Woods Michelle
Published: February 2010

Václav Havel's plays of the 1960s, 1970s, and 1980s were evaluated primarily for their dissident content. Leaving, which he wrote in 2007, followed his thirteen-year premiership and presidency of the Czech Republic. In this article, Michelle Woods asks whether perception of Havel's plays in England was confined to their alleged politics, how this view affected their translation, adaptation, and reception, and whether they can now be read beyond the ideological positions of the Cold War. She focuses on Protest at the Royal National Theatre in London in 1980 and Sorry on BBC Television in 1977, as well as on two commissions which failed to be produced: The Garden Party for the Royal Shakespeare Company in 1964 and The Conspirators for the National in 1970. She argues that the plays were fundamentally misread through the prism of a Western conception of East European dissidence, which determined whether they were produced or not, and led to the dismissal of Havel's translator, Vera Blackwell. Material from Blackwell's recently opened archive is here used to reassess her role in the dissemination of Havel's plays in the English-speaking world. Michelle Woods is Assistant Professor of English at SUNY New Paltz and is the author of Translating Milan Kundera (2006) and several articles on the translation of literature and film.
Hearing Hope: Metatheatrical Utopias in the ‘Staging’ of Radio Drama
Authors: Stephenson Jenn
Published: February 2010

The radio play has long survived the competition from television in Britain, and also has a long tradition in the German-speaking world in the form of the Hörspiel – but its strength has lain precisely in demanding a visual contribution from the listener's imagination. What happens when a radio play is ‘staged’ before a live audience? In 2005, under commission from the Royal Festival Hall, the composer Carter Burwell proposed writing a sound score for new plays; and under the banner of Theatre of the New Ear, he recruited his long-time collaborators on film, Charlie Kaufman and Joel and Ethan Coen, to write specifically for sound-only. In this article Jenn Stephenson describes the experience of ‘watching’ a radio play, and offers a theorization of its qualities and the effects on its audience. Jenn Stephenson received her PhD from the University of Toronto in 2003 and is now Associate Professor of Drama at Queen's University in Kingston, Canada. Her recent publications include articles in Theatre Journal, Journal of Dramatic Theory and Criticism, Studies in Theatre and Performance, and Theatre Research in Canada. She is co-editor of the ‘Views and Reviews’ section of Canadian Theatre Review.
INTENSIONALITY AND PARADOXES IN RAMSEY’S ‘THE FOUNDATIONS OF MATHEMATICS’
Authors: TUCKER DUSTIN
Published: February 2010

In ‘The Foundations of Mathematics’, Frank Ramsey separates paradoxes into two groups, now taken to be the logical and the semantical. But he also revises the logical system developed in Whitehead and Russell’sPrincipia Mathematica, and in particular attempts to provide an alternate resolution of the semantical paradoxes. I reconstruct the logic that he develops for this purpose, and argue that it falls well short of his goals. I then argue that the two groups of paradoxes that Ramsey identifies are not properly thought of as the logical and semantical, and that in particular, the group normally taken to be the semantical paradoxes includes other paradoxes—the intensional paradoxes—which are not resolved by the standard metalinguistic approaches to the semantical paradoxes. It thus seems that if we are to take Ramsey’s interest in these problems seriously, then the intensional paradoxes deserve more widespread attention than they have historically received.
The Importance of Social Support in Workers’ Lay Conceptualizations of Stress
Authors: Guillet Laurent , Hermand Danièle , Mullet Etienne
Published: February 2010

The present study examined workers’ lay conceptualizations of stress. The framework used was Karasek and Theorell’s (1990) “job demand-control-support” model of stress at work. It assessed the importance workers attribute to the social support factor as a determinant of work stress compared with the importance attributed to job demand and job control. It used an assessment technique – the AVERAGE program – that allows for an estimation of the weight of each factor independent of the levels of these factors. A total of 61 female and 41 male workers participated in the study. They judged the stressfulness of work situations described in terms of the three factors. Social support was found to be, by far, the most important factor for judging the stressfulness of work situations.
Volcanic gas emissions from Soufrière Hills Volcano, Montserrat 1995–2009, with implications for mafic magma supply and degassing
Authors: Christopher Thomas , Edmonds Marie , Humphreys Madeleine C. S. , Herd Richard A.
Published: February 2010

Volcanic gas emissions illustrate a complex volatile budget for Soufrière Hills Volcano, Montserrat. Fluxes of sulphur dioxide, carbon dioxide, hydrogen sulphide and hydrogen chloride (and probably water) are substantial from this arc volcano. Additional sources of volatiles in addition to the erupting andesite are required to satisfy the mass balance defined by gas emissions and petrological constraints. Mafic magma is intruded at depths of >10 km, supplying volatiles by quenching, crystallising and vesiculating at the andesite‐mafic magma interface. Sulphur, carbon dioxide and other volatiles supplied to the system migrate to the surface and their fluxes remain high while mafic recharge at depth is sustained. Decompression degassing of porphyritic andesite supplies chlorine and water to the gas plume. Chlorine partitions into vapour from the melt during periods of active extrusion, making the HCl/SO2 ratio of volcanic gases a reliable indicator of the onset of eruptive activity. Studies of this volatile budget highlight the role of deep degassing and vapour production at arc volcanoes, which are important mechanisms for driving the eruption due to its effects on magma buoyancy and the advection of heat through the system.
Geographical distribution and sources of phosphorus in atmospheric aerosol over the North Pacific Ocean
Authors: Furutani Hiroshi , Meguro Ai , Iguchi Hidenori , Uematsu Mitsuo
Published: February 2010

Atmospheric aerosol samples with two size fractions (Da ≤ 2.5 μm and Da ≥ 2.5 μm) were collected in the subtropical region of the western North Pacific (WNP) and over the central North Pacific (CNP) Ocean in summer and geographical distributions of particulate concentrations of total phosphorus (TP), water soluble fraction of phosphorus, and tracer elements (Fe, Zn, Na) were investigated. Average concentrations (in ng m−3) of TP, Fe, Zn, Na in the WNP region were 7.3 ± 4.3, 16.2 ± 17.1, 5.5 ± 7.5, and 1450 ± 700, while they were 2.5 ± 1.2, 5.9 ± 5.1, 0.9 ± 1.2, and 1480 ± 610 along the 160°W line in the CNP, respectively. Source apportionment using the tracer elements exhibited that contribution of anthropogenic source was estimated to be 38% and 18%, while that of crustal source was estimated to be about 5% for both WNP and CNP regions, respectively. Oceanic source was estimated to have a little contribution. Half or less fraction of the TP could be accounted for by the anthropogenic and crustal sources. Water solubility of the TP was found to be higher in the WNP region than the CNP region. The similar fractions of water soluble and anthropogenic contribution to the TP found in both WNP and CNP regions suggested that anthropogenic phosphorus was water soluble and dominant in the WNP region, although the unaccounted fraction occupied a large portion of the TP (47% and 76% for WNP and CNP, respectively) as insoluble form.
Potential‐field modeling of collapse‐prone submarine volcanoes in the southern Tyrrhenian Sea (Italy)
Authors: Caratori Tontini F. , Cocchi L. , Muccini F. , Carmisciano C. , Marani M. , Bonatti E. , Ligi M. , Boschi E.
Published: February 2010

Hydrothermal alteration may weaken volcanic rocks, causing the gravitational instability of portions of active volcanoes with potentially hazardous collapses. Here we show high‐resolution multibeam, magnetic and gravity surveys of the Marsili seamount, the largest active volcano of Europe located in the southern Tyrrhenian back‐arc basin. These surveys reveal zones with exceptionally low densities and with vanishing magnetizations, due probably to the comminution of basalts during hyaloclastic submarine eruptions and to their post‐eruptive hydrothermal alteration. The location of these regions correlates with morphological data showing the occurrence of past collapses. Similar evidence has been obtained from pre‐existing data at Vavilov Seamount, another older volcanic system in the Tyrrhenian back‐arc basin. Here a large volume of at least 50 km3 may have collapsed in a single event from its 40 km long western flank. Given the similarities between these volcanoes, a large collapse event may also be expected at Marsili.
Kolmogorov versus Iroshnikov‐Kraichnan spectra: Consequences for ion heating in the solar wind
Authors: Ng C. S. , Bhattacharjee A. , Munsi D. , Isenberg P. A. , Smith C. W.
Published: February 2010

Whether the phenomenology governing MHD turbulence is Kolmogorov or Iroshnikov‐Kraichnan (IK) remains an open question, theoretically as well as observationally. The ion heating profile observed in the solar wind provides a quantitative, if indirect, observational constraint on the relevant phenomenology. Recently, a solar wind heating model based on Kolmogorov spectral scaling has produced reasonably good agreement with observations, provided the effect of turbulence generation due to pickup ions is included in the model. Without including the pickup ion contributions, the Kolmogorov scaling predicts a proton temperature profile that decays too rapidly beyond a radial distance of 15 AU. In the present study, we alter the heating model by applying an energy cascade rate based on IK scaling and show that the model yields higher proton temperatures, within the range of observations, with or without the inclusion of the effect due to pickup ions. Furthermore, the turbulence correlation length based on IK scaling seems to follow the trend of observations better.
A comparison study of zonal drift velocities measurements as seen by MF spaced antenna and HF Doppler radar in the Indian dip equatorial mesospheric and lower thermospheric (80–100 km) region
Authors: Ramkumar T. K. , Gurubaran S. , Rajaram R. , Tiwari D. , Viswanathan K. S.
Published: February 2010

The simultaneous measurements of zonal drift velocities, observed in the heights of 84–98 km in the Indian geomagnetic dip equatorial region by an medium frequency (MF, 1.98 MHz) spaced antenna and a high‐frequency (HF, 18 MHz) Doppler radars, are compared on selected few days in the solar maximum years of 1998, 1999, and 2000. The agreement between the two radar measurements is found to be good below about 88 km, where the neutral turbulence induced ionospheric irregularities are more predominant. Above 90 km, however, the agreement becomes poor and at the highest height of 98 km it becomes the least. At this height, more often the HF Doppler radar shows a westward drift of about 200 m/s whereas the MF spaced antenna radar values lie within ±10 m/s and sometimes attain maximum values of ±50 m/s. Detailed discussions are made on the possible sources of underestimation of the drift velocities measured by the MF radar and the nature of scattering irregularities that are produced because of large neutral turbulences and plasma instabilities. It is suggested that these neutral and plasma turbulences (particularly type II plasma irregularities) contribute in a different manner to different radar frequencies and techniques and hence very different drift velocities in the heights of 90–100 km particularly in the geomagnetic dip equatorial region. Discussions are also made on (1) the real atmospheric and ionospheric physical process prevailing in the 90–100 km region and (2) the technical aspects of the radars that limits them to measure only particular types of motion in this region.
First principles study of thermodynamics and phase transition in low‐pressure (P21/c) and high‐pressure (C2/c) clinoenstatite MgSiO3
Authors: Yu Yonggang G. , Wentzcovitch Renata M. , Angel Ross J.
Published: February 2010

Using first principles quasi‐harmonic theory, we have investigated the vibrational and thermodynamic properties of P21/c and C2/c MgSiO3 clinoenstatites. Very good agreement between experimentally measured thermodynamic properties, such as equation of state, and those predicted by the local density approximation (LDA) functional has been found. The level of agreement found in these chain silicates is comparable to that found in framework silicates such as MgSiO3 perovskite. The phase boundaries calculated by the LDA and the generalized gradient approximation (GGA) bracket the experimentally measured ones following the established trend that the GGA functional overestimates the transition pressure while the LDA functional underestimates it. The calculated Clapeyron slope is 2.9 MPa K−1 and is used to constrain the position of the 3‐pyroxene (P21/c, C2/c, and Pbca) triple point in MgSiO3, with the aid of room temperature experimental hysteresis in the P21/c to C2/c transition.
Administration of a low dose of sildenafil for 1 week decreases intrahepatic resistance in rats with biliary cirrhosis: the role of NO bioavailability
Authors: Lee Kuei-Chuan , Yang Ying-Ying , Huang Yi-Tsau , Lee Fa-Yauh , Hou Ming-Chih , Lin Han-Chieh , Lee Shou-Dong
Published: February 2010

Increasing NO bioavailability improves hepatic endothelial dysfunction, which ameliorates intrahepatic resistance and portal hypertension. Acute administration of sildenafil increases hepatic production of NO with a reduction in hepatic sinusoid resistance in cirrhotic patients and enhances the vasorelaxation response to NO in cirrhotic rat livers. However, the mechanisms were still unclear. Therefore, our present study aims to evaluate the effects and mechanisms of administration of sildenafil for 1 week on the hepatic microcirculation of cirrhotic rats. Cirrhosis was induced by bile duct ligation with sham-operated rats serving as normal controls. Intrahepatic resistance was evaluated by in situ liver perfusion. Expression of phospho-eNOS (endothelial NO synthase), iNOS (inducible NO synthase), phospho-Akt, PDE-5 (phosphodiesterase-5) and sGC (soluble guanylate cyclase) were determined by Western blot analysis. Biosynthesis of BH4 (tetrahydrobiopterin) and GTPCH-I (GTP cyclohydrolase I) activity were examined by HPLC. Intravital microscopy was used to observe the direct change in hepatic microcirculation. In cirrhotic rat livers, sildenafil treatment increased hepatic sinusoid volumetric flow, NO bioavailability, BH4, GTPCH-I activity, and the protein expression of phospho-Akt, phospho-eNOS and sGC. These events were associated with reduced protein expression of PDE-5, portal perfusion pressure and portal vein pressure. In contrast, sham rats did not produce any significant change in these measurements. In conclusion, sildenafil treatment improves endothelial dysfunction by augmenting NO bioavailability in the hepatic microcirculation.
Should We Use Telegraphic or Grammatical Input in the Early Stages of Language Development With Children Who Have Language Impairments? A Meta-Analysis of the Research and Expert Opinion
Authors: van Kleeck Anne , Schwarz Amy Louise , Fey Marc , Kaiser Ann , Miller Jon , Weitzman Elaine
Published: February 2010

Purpose

In working with children with language impairments, some clinical scholars and clinicians advocate using input that is simplified to the point of being ungrammatical (telegraphic input), while others advocate simplified but grammatical input. This article considers 2 types of external evidence on this topic.

Method

First, a meta-analysis of relevant research, including intervention studies and processing studies, is reported. Next, 4 experts present their opinions.

Results

Children in the majority of the intervention studies showed no difference in language comprehension based on type of input, although 1 study with very few children favored telegraphic input for language production. In the processing studies, which measured immediate comprehension, children from clinical populations responded inconsistently when listening to the 2 types of input. Children who had typical language, however, favored grammatical input in their responses. Regarding the experts' opinions, 2 suggest that telegraphic input is sometimes warranted; 1, who previously indirectly promoted its occasional use, no longer believes it should be used; and 1 provides reasons why telegraphic input should not be used and may even be harmful.

Conclusions

Empirical findings and expert views are summarized as ways of informing parents of the weak evidence base regarding the best type of input.
Boron ion source based on planar magnetron discharge in self-sputtering mode
Authors: Gushenets V. I. , Hershcovitch A. , Kulevoy T. V. , Oks E. M. , Savkin K. P. , Vizir A. V. , Yushkov G. Yu.
Published: February 2010

An ion source based on a planar magnetron sputtering device with thermally isolated target has been designed and demonstrated. For a boron sputtering target, high target temperature is required because boron has low electrical conductivity at room temperature, increasing with temperature. The target is well-insulated thermally and can be heated by an initial low-current, high-voltage discharge mode. A discharge power of 16 W was adequate to attain the required surface temperature (400 °C), followed by transition of the discharge to a high-current, low-voltage mode for which the magnetron enters a self-sputtering operational mode. Beam analysis was performed with a time-of-flight system; the maximum boron ion fraction in the beam is greater than 99%, and the mean boron ion fraction, time-integrated over the whole pulse length, is about 95%. We have plans to make the ion source steady state and test with a bending magnet. This kind of boron ion source could be competitive to conventional boron ion sources that utilize compounds such as BF3, and could be useful for semiconductor industry application.
Development of a laser-focused ion beam combination machine
Authors: Yoshida Y. , Masuzawa T. , Ikeda H. , Oguchi K. , Yamagishi H. , Wakabayashi Y.
Published: February 2010

We have developed a laser and focused ion beam (FIB) compound system to process an optical component device with an ultrafine precision minute surface structure and a micromedical device. This machine consists of an FIB and three types of lasers with an atomic force microscope. This system can fabricate decamicrometer area by laser and submicrometer area by FIB at one chuck. When processing the press mold die of a microlens array (10×10) in a glasslike carbon with a femtosecond laser, a diameter of 3.2 μm and depth of 0.43 μm are obtained. However, the surface roughness is more than Rz=0.5 μm. After this process, we finished this surface with the use of the FIB. As a result, the surface roughness is less than Rz=0.05 μm.
Study on transport of negative ion plasma using dc laser photodetachment method
Authors: Shimamoto S. , Kasuya T. , Kimura Y. , Miyamoto N. , Matsumoto Y. , Wada M.
Published: February 2010

Transport of negative ion containing plasma was studied in a hydrogen plasma by injecting a semiconductor laser to make an electron density perturbation by photodetachment of negative ions. Change due to laser irradiation on electron saturation current to a Langmuir probe and that on electron current extracted through an orifice biased at the anode potential were measured phase sensitively by a lock-in-amplifier. The measured transport velocity of the negative ion containing plasma was about 1.4×105 cm/s for both cases. The photodetachment signal measured through the orifice had given a larger ratio of negative ion density to electron density. Change in transport of negative ion containing plasma around the Langmuir probe has been also investigated by detecting photodetachment signal onto electron current extracted through an orifice.
Cosmological particle creation in states of low energy
Authors: Degner Andreas , Verch Rainer
Published: February 2010

The recently proposed states of low energy provide a well-motivated class of reference states for the quantized linear scalar field on cosmological Friedmann–Robertson–Walker space-times. The low energy property of a state is localized close to some value of the cosmological time coordinate. We present calculations of the relative cosmological particle production between a state of low energy at early time and another such state at later time. In an exponentially expanding Universe, we find that the particle production shows oscillations in the spatial frequency modes. The basis of the method for calculating the relative particle production is completely rigorous. Approximations are only used at the level of numerical calculation.
Photoresponsive characteristics and hysteresis of soluble 6,13-bis(triisopropyl-silylethynyl)-pentacene-based organic thin film transistors with and without annealing
Authors: Cho Mi Yeon , Han Yoon Deok , Kang Han Saem , Kim Kihyun , Kim Kyung Hwan , Cho Min Ju , Choi Dong Hoon , Joo Jinsoo
Published: February 2010

We report on the photoresponsive characteristics and hysteresis of soluble 6,13-bis(triisopropyl-silylethynyl; TIPS)-pentacene-based organic thin film transistors (OTFTs) with and without an annealing process. Under incident light, the hysteresis and memory effect increased for the annealed devices through photoinduced electron trapping and recombination at the gate-dielectric-semiconductor interface. To investigate the cause of the photoenhanced memory effect and hysteresis, we estimated the trapped electron densities from the threshold shift, while applying a gate bias to the annealed OTFTs under both dark and light conditions. A comparison of the characteristics of OTFT devices that are prepared under various conditions suggests that deep electron traps might be caused by the appearance of a domain boundary (i.e., cracks) in the annealed TIPS-pentacene film during the annealing process, which showed stable photoresponsive characteristics but relatively lower mobility.
Index formulas and charge deficiencies on the Landau levels
Authors: Goffeng Magnus
Published: February 2010

The notion of charge deficiency by Avron et al. [“Charge deficiency, charge transport and comparison of dimensions,” Commun. Math. Phys. 159, 399 (1994)] is studied from the view of K-theory of operator algebras and is applied to the Landau levels in R2n. We calculate the charge deficiencies at the higher Landau levels in R2n by means of an Atiyah–Singer-type index theorem.
Simulation of charge breeding of rubidium using Monte Carlo charge breeding code and generalized ECRIS model
Authors: Zhao L. , Cluggish B. , Kim J. S. , Pardo R. , Vondrasek R.
Published: February 2010

A Monte Carlo charge breeding code (MCBC) is being developed by FAR-TECH, Inc. to model the capture and charge breeding of 1+ ion beam in an electron cyclotron resonance ion source (ECRIS) device. The ECRIS plasma is simulated using the generalized ECRIS model which has two choices of boundary settings, free boundary condition and Bohm condition. The charge state distribution of the extracted beam ions is calculated by solving the steady state ion continuity equations where the profiles of the captured ions are used as source terms. MCBC simulations of the charge breeding of Rb+ showed good agreement with recent charge breeding experiments at Argonne National Laboratory (ANL). MCBC correctly predicted the peak of highly charged ion state outputs under free boundary condition and similar charge state distribution width but a lower peak charge state under the Bohm condition. The comparisons between the simulation results and ANL experimental measurements are presented and discussed.
A full description of the integrability condition for the twistor equation in curved space-times and new wave equations for conformally invariant spinor fields
Authors: Cardoso J. G.
Published: February 2010

The consistency condition associated with the feasibility of setting out the twistor equation in curved space-times is considered within the frameworks of the Infeld–van der Waerden γε-formalisms. It appears that the ε-formalism version of the condition bears a simpler form because of the applicability of a peculiar differential property of spin-tensor densities whose weights and antiweights are suitably related to their valences. Certain calculational techniques are likewise utilized for deriving a set of new wave equations.
Selection and generation of waveforms for differential mobility spectrometry
Authors: Krylov Evgeny V. , Coy Stephen L. , Vandermey John , Schneider Bradley B. , Covey Thomas R. , Nazarov Erkinjon G.
Published: February 2010

Devices based on differential mobility spectrometry (DMS) are used in a number of ways, including applications as ion prefilters for API-MS systems, as detectors or selectors in hybrid instruments (GC-DMS, DMS-IMS), and in standalone systems for chemical detection and identification. DMS ion separation is based on the relative difference between high field and low field ion mobility known as the alpha dependence, and requires the application of an intense asymmetric electric field known as the DMS separation field, typically in the megahertz frequency range. DMS performance depends on the waveform and on the magnitude of this separation field. In this paper, we analyze the relationship between separation waveform and DMS resolution and consider feasible separation field generators. We examine ideal and practical DMS separation field waveforms and discuss separation field generator circuit types and their implementations. To facilitate optimization of the generator designs, we present a set of relations that connect ion alpha dependence to DMS separation fields. Using these relationships we evaluate the DMS separation power of common generator types as a function of their waveform parameters. Optimal waveforms for the major types of DMS separation generators are determined for ions with various alpha dependences. These calculations are validated by comparison with experimental data.
Dynamics and shape instability of thin viscous sheets
Authors: Filippov Andrey , Zheng Zheming
Published: February 2010

An asymptotic theory for predicting the thickness distribution and geometry of the boundaries of a thin nearly planar fluid sheet and analyzing the stability of its shape is developed starting from the balance law for mass and momentum for a continuous medium. The resulting equations comprise a transient two-dimensional model where the sheet thickness and out of plane displacement are additional distributed parameters along with the continuum velocities. The analysis of the sheet motion in the transverse direction showed that the existence of compressive stresses inevitably leads to viscous sheet shape instability, while the equations describing the out of plane sheet displacement become of mixed type. As examples, two practical problems involving nonisoviscous sheets have been considered: a two-dimensional viscous sheet, which shape is unstable in the case when the compressive stress is applied at the exit end, and a three-dimensional problem of viscous sheet redraw (constant stretching), where the existence of the compressive stresses leads to the development of hyperbolic zones in the sheet, resulting in the sheet shape instability.
Investigation on nonedible vegetable oil as a compression ignition engine fuel in sustaining the energy and environment
Authors: Saravanan S. , Nagarajan G. , Rao G. Lakshmi Narayana
Published: February 2010

In the present investigation, a high free fatty acid (FFA) crude rice bran oil (CRBO), a renewable nonedible vegetable oil was tested on a direct injection compression ignition engine to find its ability to replace diesel oil and reduce the pollutants emitted. Three CRBO samples of different FFAs were tested in blended form to analyze the effects of high FFA with respect to engine performance and emission characteristics. With CRBO blends unburned hydrocarbon emissions were decreased significantly at all loads as a result of enhanced thermal oxidation inside the combustion chamber. The nitrogen oxides (NOx) emissions were reduced at lower loads and particulate emission reduced at higher loads. A marginal increase in carbon monoxide (CO) emission was noticed at all loads relative to diesel. The brake thermal efficiency of the engine was reduced marginally with CRBO blends. The experimental results show that high FFA CRBO can be used to partially replace diesel oil for a more sustainable energy and environment.
On the structure of Verma modules over the W-algebra W(2,2)
Authors: Jiang Wei , Pei Yufeng
Published: February 2010

In this paper, we describe the structure of Verma modules over the W-algebra W(2,2). We show that either a Verma module over W(2,2) is irreducible or its maximal submodule is cyclic.
Integrable properties of the general coupled nonlinear Schrödinger equations
Authors: Wang Deng-Shan , Zhang Da-Jun , Yang Jianke
Published: February 2010

In this paper, a general integrable coupled nonlinear Schrödinger system is investigated. In this system, the coefficients of the self-phase modulation, cross-phase modulation, and four-wave mixing terms are more general while still maintaining integrability. The N-soliton solutions in this system are obtained by the Riemann–Hilbert method. The collision dynamics between two solitons is also analyzed. It is shown that this collision exhibits some new phenomena (such as soliton reflection) which have not been seen before in integrable systems. In addition, the recursion operator and conservation laws for this system are also derived.
Correlation inequalities for quantum spin systems with quenched centered disorder
Authors: Contucci Pierluigi , Lebowitz Joel L.
Published: February 2010

It is shown that random quantum spin systems with centered disorder satisfy correlation inequalities previously proved [P. Contucci and J. Lebowitz, Ann. Henri Poincare 8, 1461 (2007)] in the classical case. Consequences include monotone approach of pressure and ground state energy to the thermodynamic limit. Signs and bounds on the surface pressures for different boundary conditions are also derived for finite range potentials.
Inhomogeneous boundary value problem for Hartree-type equation
Authors: Ma Li , Cao Pei
Published: February 2010

In this paper, we settle the problem for time-dependent Hartree equation with inhomogeneous boundary condition in a bounded smooth domain in RN. A global existence and uniqueness result for H1 solution is derived.
Slit waveguide based terahertz near-field microscopy: Prospects and limitations
Authors: Merbold Hannes , Feurer Thomas
Published: February 2010

We experimentally and numerically investigate the transmission of single cycle terahertz pulses through subwavelength slit apertures featuring zero cutoff frequency and very low attenuation. Employing a polaritonic approach we demonstrate that wave forms transmitted through slit samples with slit widths as small as λ/1000 can be visualized and analyze the applicability of this approach to terahertz near-field microscopy. Finite element simulations are used to quantitatively investigate resolution limitations due to imperfect experimental configurations. Our results show that resolutions on the scale of the slit width are possible; however, they demand an accurate control of the distance between the imaging aperture and the sample. This is because the presence of small gaps leads to around-the-bend waveguiding effects resulting in a significant reduction of the attainable resolution.
Temperature and excitation power dependent photoluminescence intensity of GaInN quantum wells with varying charge carrier wave function overlap
Authors: Netzel C. , Hoffmann V. , Wernicke T. , Knauer A. , Weyers M. , Kneissl M. , Szabo N.
Published: February 2010

For the realization and the improvement of GaN-based optoelectronic devices (light emitting diodes and laser diodes) emitting from the ultraviolet to the red wavelength range GaInN quantum well structures with high internal quantum efficiency are of great importance. To determine parameters which affect the internal quantum efficiency, we have analyzed the emission intensity of GaInN quantum well structures with varied electron and hole wave function overlap by temperature and excitation power dependent and by time-resolved photoluminescence. The quantum confined Stark effect reduces the temperature dependent photoluminescence emission intensity for thick polar quantum wells at low temperature. But near room temperature, these thick polar GaInN quantum wells feature less relative intensity loss than thinner polar quantum wells. This behavior can partially be assigned to increased screening effects and higher quantum well barriers for thicker quantum wells. Additionally, excitation power dependent photoluminescence points to a transition from a radiative recombination based on excitons at 10 K to a bimolecular recombination at room temperature for thick c-plane quantum wells. This transition may also affect the intensity decrease by a changed carrier diffusivity.
Band bending effect induced by gate voltage on the charge loss behavior of charge trap flash memory devices
Authors: Chang M. , Hwang H. , Jeon S.
Published: February 2010

We found that the polarity of the gate voltage (Vg) during the retention characteristics for a SiO2/Si3N4/Al2O3 (ONA) stack can affect the charge loss direction, due to band bending. Positive Vg could induce electron de-trapping through Al2O3, while a negative Vg could induce the same through SiO2. Consequently, the charge loss rates exhibited a hairpin curve with Vg. We clearly observed that increases of the SiO2 thickness of the ONA stack induced negative shifts of hairpin curve. This result suggests that the dominant charge loss path could be changed from SiO2 to Al2O3 by increasing the SiO2 thickness without Vg.
Griffiths phase and exchange bias in La1−xCaxMnO3 (x=0.50, 0.67, and 0.75) nanoparticles
Authors: Zhou S. M. , Zhao S. Y. , Guo Y. Q. , Zhao J. Y. , Shi L.
Published: February 2010

The magnetic properties of La1−xCaxMnO3 (x=0.50, 0.67, and 0.75) nanoparticles have been systemically investigated in this work. It is found that although their bulk counterparts have different magnetic and charge ordered states, the nanoparticles show no long-range charge ordered transition but very similar magnetic behaviors, i.e., a Griffiths phase appearing below ∼300 K and a ferromagnetic ordered state present below ∼270 K. The similarity suggests that the enhanced ferromagnetic behavior at low temperatures in the nanoparticles may originate from the development of the ferromagnetic correlations already present at high temperature upon cooling due to the suppression of the charge ordered state. Moreover, the field-cooling magnetic hysteresis loops reveal that exchange bias phenomena are present in the nanoparticles, which is of special interest for potential applications.