bluuebunny/crossref_metadata_2025 huggingface dataset:
Defending the Rawlsian League of Peoples: A Critical Comment on Tan
Authors: MERTENS THOMAS
Published: January 2006

In his well-written and well-argued paper ‘International Toleration: Rawlsian versus Cosmopolitan’, Kok-Chor Tan raises the important question as to where the limits of toleration are to be drawn. This is an important issue not only from the perspective of international law, but also for any domestic society. Toleration is never an automatic element or quality of any society, but has to be defended against the ever present danger of intolerance and repression. This is especially the case in the post-9/II era with regard to Islam, as it is not always easy to separate serious analysis of this religion from outright prejudices against its believers. With regard to Islamic minorities, the present attitude of some ‘Western’ majorities does not always reflect an attitude of respect, although this is not often admitted. It is not argued that Islamic minorities and other immigrants should adapt to the culture of the majorities because minorities have to give in to majorities on the basis of democracy; instead, it is claimed that Western majorities live in accordance with universal values. As Western societies have incorporated universal values formulated for the first time in the age of Enlightenment, they can rightly require from immigrants and minorities that they give up part of their values and identities without any real loss on their side. In forcing immigrants to adapt to Western values, majorities are merely liberating them from outdated particularistic codes and worldviews, thus enabling them to be free in accordance with truly universal values. This, obviously, is a peculiar way of understanding the Enlightenment, not with Kant as a perpetual challenge (‘we do not live in an enlightened age, but in an age of enlightenment’), but as something that is achieved and stably embodied in ‘our’ Western societies. Immigrants and minority members can reasonably be asked to identify with such societies. Although such a demand to assimilate might at first glance be seen as testifying to intolerance, in reality this is not the case. Why should we allow others to live in error? In the face of truth, toleration is a superfluous virtue. It goes almost without saying that this view, which is deemed by some as Enlightenment fundamentalism, contradicts the spirit with which Locke and Spinoza in the seventeenth century proclaimed the superior value of tolerance. They argued that all religions claim for themselves to be the one and only true religion and that the best attitude among the contenders of different beliefs would be one of tolerance: nobody can prove convincingly to the other side of the religious divide the truth of his own religion and the falseness of all other religions; and since ‘no man can conform his faith to the dictates of another (since) all the life and the power of true religion consists in the inward and full persuasion of the mind’ (Locke), the use of earthly powers is inappropriate and unjust.
The International Court of Justice Judgment in the Benin–Niger Border Dispute: The Interplay of Titles and ‘Effectivités’ under the Uti Possidetis Juris Principle
Authors: SPADI FABIO
Published: January 2006

The chamber of the ICJ entrusted with solving the Benin–Niger dispute based its judgment on the colonial heritage left to the two countries at the time of their independence, as prescribed by the uti possidetis juris principle. The dispute actually stemmed from that heritage: the chamber's role was to interpret and clarify it. But while the uti possidetis juris principle underlines border stability, features such as river boundaries, because of their intrinsic movable nature, can put this stability under intense strain. The judgment lends itself to further reflections on this dichotomy, since the disputed areas revolved around two rivers.
Bridging the Conceptual Chasm: Superior Responsibility as the Missing Link between State and Individual Responsibility under International Law
Authors: REID NATALIE L.
Published: January 2006

Commonly accepted distinctions between state and individual responsibility have created a conceptual chasm between the two sets of legal rules, which is in turn reinforced by different underlying theoretical conceptions of the international system. As a result of this conceptual chasm, current understandings of responsibility fail to describe adequately either the sources of harm to individuals or groups within states, or the changing relationships between individuals, non-state groups, and states. The doctrine of superior responsibility, however, offers the possibility for reconciliation of state and individual responsibility rules, by providing a theoretical basis and a practical method of developing understandings of liability for breaches of fundamental norms that more accurately reflect the channels of responsibility in contemporary conflict situations.
“AFFECT WITHOUT RECOLLECTION” IN POST-TRAUMATIC STRESS DISORDER WHERE HEAD INJURY
CAUSES ORGANIC AMNESIA FOR THE EVENT
Authors: King Nigel S.
Published: January 2006

Ehlers and Clark (2000) recently published a rigorous cognitive behavioural model of PTSD. Part of the model explains how the phenomenon of “affect without recollection” can emerge in PTSD. This happens when the re-experiencing phenomena occur without explicit or conscious recall of the parts of the traumatic event from whence the phenomena originated. The following paper presents a case study of a man with PTSD and head injury in which there was complete organic amnesia for the trauma but where re-experiencing of the event occurred via
implicit conditioned responses to reminders of the event. It provides elegant supportive evidence for the phenomenon of “affect without recollection” where both PTSD and severe head injury are present.
Editorial
Authors: Brunstein Joachim C. , Spörer Nadine
Published: January 2006

Editorial: Themes and Trends in the Years 2002 to 2004
Leistungsängstlichkeit: Facetten, Fächer, Fachfacetten?
Authors: Sparfeldt Jörn R. , Schilling Susanne R. , Rost Detlef H. , Stelzl Ingeborg , Peipert Dominique
Published: January 2006

Zusammenfassung: Im Rahmen der Leistungsängstlichkeitsforschung werden seit längerem sowohl die Relevanz der Inhaltsbereiche (d. h. Schulfächer) als auch die verschiedener Leistungsangstfacetten thematisiert. N = 1213 Schülerinnen und Schüler der 8. bis 10. Klasse bearbeiteten einen Fragebogen, der beide Aspekte simultan berücksichtigt. Mittels konfirmatorischer Faktorenanalysen konnten die drei postulierten Angstfacetten Besorgtheit, Aufgeregtheit und Kognitive Angstmanifestation in jedem der vier betrachteten Schulfächer (Mathematik, Deutsch, Englisch, Physik) bestätigt werden; auch ließen sich die vier Fächer in jeder der drei Angstfacetten trennen. Anschließende (konfirmatorische) Modellvergleiche dokumentieren die Bedeutung einer simultanen Beachtung beider Gliederungsaspekte. Differenzielle Beziehungen der schulfachspezifischen Leistungsangstfacetten zu Zensuren weisen auf deren konvergente/divergente Validität hin.
Implementation eines Programms zur Vermittlung von Lesestrategien im Deutschunterricht
Authors: Souvignier Elmar , Mokhlesgerami Judith
Published: January 2006

Zusammenfassung: Es wurde geprüft, in welchem Maße Lehrermerkmale die Wirksamkeit eines neu entwickelten Unterrichtsprogramms beeinflussen. Dazu wurde in 17 fünften Klassen (n = 509 Schülerinnen und Schüler) ein Programm zur Förderung der Lesekompetenz im Deutschunterricht durchgeführt. Als programmnahe Einflussfaktoren wurden Vollständigkeit der Programmdurchführung, inhaltliche Nähe des Unterrichts zum Programm und Flexibilität der Durchführung herangezogen. Als allgemeine Merkmale der Unterrichtsqualität wurden Klassenführung, Strukturierung, fachliche Unterstützung, soziales Klima und die Motivierungsqualität erhoben. Zusätzlich wurden handlungsleitende Überzeugungen in Bezug auf das Unterrichten im Fach Deutsch erfragt. Kriterium für den Lernerfolg der Schülerinnen und Schüler war das Wissen über Lesestrategien nach der Programmdurchführung. Es zeigte sich, dass die Lernfortschritte der Schülerinnen und Schüler maßgeblich von der Motivierungsqualität des Unterrichts abhängen. Positiv auf den Lernerfolg wirkten sich zudem die Strukturiertheit des Unterrichts sowie die Überzeugung auf Seiten der Lehrenden aus, dass Lernprozesse eine aktive Konstruktion von Wissen darstellen.
Sensitivity of Moderate Resolution Imaging Spectroradiometer (MODIS) terrestrial primary production to the accuracy of meteorological reanalyses
Authors: Zhao Maosheng , Running Steven W. , Nemani Ramakrishna R.
Published: January 2006

The Moderate Resolution Imaging Spectroradiometer (MODIS) on board NASA's satellites, Terra and Aqua, dramatically improves our ability to accurately and continuously monitor the terrestrial biosphere. MODIS information is used to estimate global terrestrial primary production weekly and annually in near‐real time at a 1‐km resolution. MODIS terrestrial primary production requires daily gridded assimilation meteorological data as inputs, and the accuracy of the existing meteorological reanalysis data sets show marked differences both spatially and temporally. This study compares surface meteorological data sets from three well‐documented global reanalyses, NASA Data Assimilation Office (DAO), European Centre for Medium‐Range Weather Forecasts (ECMWF) (ERA‐40) and National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis 1, with observed weather station data and other gridded data interpolated from the observations, to evaluate the sensitivity of MODIS global terrestrial gross and net primary production (GPP and NPP) to the uncertainties of meteorological inputs both in the United States and the global vegetated areas. NCEP tends to overestimate surface solar radiation, and underestimate both temperature and vapor pressure deficit (VPD). ECMWF has the highest accuracy but its radiation is lower in tropical regions, and the accuracy of DAO lies between NCEP and ECMWF. Biases in temperature are mainly responsible for large VPD biases in reanalyses. MODIS NPP contains more uncertainties than GPP. Global total MODIS GPP and NPP driven by DAO, ECMWF, and NCEP show notable differences (>20 Pg C/yr) with the highest estimates from NCEP and the lowest from ECMWF. Again, the DAO results lie somewhere between NCEP and ECMWF estimates. Spatially, the larger discrepancies among reanalyses and their derived MODIS GPP and NPP occur in the tropics. These results reveal that the biases in meteorological reanalyses can introduce substantial error into GPP and NPP estimations, and emphasize the need to minimize these biases to improve the quality of MODIS GPP and NPP products.
Mass density inferred from toroidal wave frequencies and its comparison to electron density
Authors: Takahashi Kazue , Denton Richard E. , Anderson Roger R. , Hughes W. Jeffrey
Published: January 2006

We have estimated the magnetospheric local mass density using the frequency of the toroidal standing Alfvén waves detected with the magnetic (B) and electric (E) field experiments on the Combined Release and Radiation Effects Satellite (CRRES), which had a low‐latitude elliptical orbit (6.3 RE apogee and 18° inclination). A 73‐day period in 1991, which included several geomagnetic storms, was chosen for analysis because the spacecraft was located on the afternoon sector where toroidal waves are routinely excited. Dynamic spectra of the B and E fields were generated for each CRRES orbit for visual identification of toroidal mode ULF waves excited at a number of harmonics. The fundamental mode is the most persistent feature in the spectra, and this mode appears more clearly in the electric field than in the magnetic field. For statistical analysis we determined the fundamental frequency f1 from a separate set of electric field spectra that were computed in a moving 20‐min time window with 10‐min overlap. The frequency is in the range of 1.7–14.2 mHz. The local mass density consistent with f1 was obtained by numerically solving a magnetohydrodynamic wave equation that incorporated the Tsyganenko magnetic field model and an analytical form of field‐line mass density variation that was derived from a recent study of toroidal harmonics. We combined the estimated mass density with the local electron number density ne derived from the plasma wave spectra at CRRES to obtain the local average ion mass M (=ρ/ne). A total of 1094 M samples were obtained, with the majority (95%) coming from the plasmatrough region (ne < 100 cm−3). Our technique for the mass density is confirmed to be reliable because only 3.5% of the M samples lie outside the physically plausible range of 1 amu (all‐H+ plasma) to 16 amu (all‐O+ plasma). The average ion mass has a median value of 3.0 amu and depends on geomagnetic activity. For example, M is 2.5 amu for Dst = 0 and 4.1 amu for Dst = −60 nT. There is a similar dependence of M on Kp, but only when the Kp values are averaged over a few days. There is no strong dependence of M on the magnetic field L shell in the range L = 4 to L = 8 covered by the f1 samples, although M is significantly low (<2 amu) for the plasmaspheric regime (ne > 100 cm−3).
Pharmacological characterization of inhibitory effects of postsynaptic opioid and cannabinoid receptors on calcium currents in neonatal rat nucleus tractus solitarius
Authors: Endoh Takayuki
Published: January 2006

The profile of opioid and cannabinoid receptors in neurons of the nucleus tractus solitarius (NTS) has been studied using the whole‐cell configuration of the patch clamp technique.

Experiments with selective agonists and antagonists of opioid, ORL and cannabinoid receptors indicated that μ‐opioid, κ‐opioid, ORL‐1 and CB1, but not δ‐opioid, receptors inhibit VDCCs in NTS.

Application of [D‐Ala2, N‐Me‐Phe4, Gly5‐ol]‐enkephalin (DAMGO; μ‐opioid receptor agonist), Orphanin FQ (ORL‐1 receptor agonist) and WIN55,122 (CB1 receptor agonist) caused inhibition of IBa in a concentration‐dependent manner, with IC50's of 390 nM, 220 nM and 2.2 μM, respectively.

Intracellular dialysis of the Gi‐protein antibody attenuated DAMGO‐, Orphanin FQ‐ and WIN55,122‐induced inhibition of IBa.

Both pretreatment with adenylate cyclase inhibitor and intracellular dialysis of the protein kinase A (PKA) inhibitor attenuated WIN55,122‐induced inhibition of IBa but not DAMGO‐ and Orphanin FQ‐induced inhibition.

Mainly N‐ and P/Q‐type VDCCs were inhibited by both DAMGO and Orphanin FQ, while L‐type VDCCs were inhibited by WIN55,122.

These results suggest that μ‐ and κ‐opioid receptors and ORL‐1 receptor inhibit N‐ and P/Q‐type VDCCs via Gαi‐protein βγ subunits, whereas CB1 receptors inhibit L‐type VDCCs via Gαi‐proteins involving PKA in NTS.

British Journal of Pharmacology (2006) 147, 391–401. doi:10.1038/sj.bjp.0706623
The ‘allosteric modulator’ SCH‐202676 disrupts G protein‐coupled receptor function via sulphydryl‐sensitive mechanisms
Authors: Lewandowicz Anna M , Vepsäläinen Jouko , Laitinen Jarmo T
Published: January 2006

Previous studies suggest that the thiadiazole compound SCH‐202676 (N‐(2,3‐diphenyl‐1,2,4‐thiadiazol‐5‐(2H)‐ylidene)methanamine) acts as an allosteric modulator of a variety of structurally distinct G protein‐coupled receptors (GPCRs). It was postulated that SCH‐202676 would directly bind a structural motif in the receptor molecule common to divergent members of the GPCR family. The molecular mechanisms of such a promiscuous action, however, remain obscure.

To clarify the mechanism of SCH‐202676 action, we used the functional approach of [35S]GTPγS autoradiography with rat brain cryostat sections together with classical membrane [35S]GTPγS binding assays to evaluate how the thiadiazole affects G protein activity mediated by various receptors linked to the Gi‐family of G proteins.

We found that in the absence of dithiotreitol (DTT), SCH‐202676 (10−7–10−5 M) elicits nonspecific effects in the [35S]GTPγS‐based G protein activation assays, thereby severely compromising interpretations on the compounds ability to allosterically inhibit receptor‐mediated G protein activity. Such a nonspecific behaviour was fully reversed upon addition of DTT (1 mM), revealing thiol‐based mechanism of action.

In routine incubations containing DTT, SCH‐202676 had no effect on receptor‐driven G protein activity, as assessed for adenosine A1, α2‐adrenergic, cannabinoid CB1, lysophosphatidic acid LPA1, muscarinic M2/M4, purinergic P2Y12 or sphingosine 1‐phosphate receptors, suggesting that the thiadiazole does not act as an allosteric modulator of GPCR function.

1H NMR analysis indicated that SCH‐202676 underwent structural changes after incubation with the reducing agent DTT or with brain tissue.

We conclude that SCH‐202676 modulates GPCRs via thiol modification rather than via true allosteric mechanisms.

British Journal of Pharmacology (2006) 147, 422–429. doi:10.1038/sj.bjp.0706624
A new endogenous ATP analog (ApppI) inhibits the mitochondrial adenine nucleotide translocase (ANT) and is responsible for the apoptosis induced by nitrogen‐containing bisphosphonates
Authors: Mönkkönen Hannu , Auriola Seppo , Lehenkari Petri , Kellinsalmi Maarit , Hassinen Ilmo E , Vepsäläinen Jouko , Mönkkönen Jukka
Published: January 2006

Bisphosphonates are currently the most important class of antiresorptive drugs used for the treatment of diseases with excess bone resorption. On the basis of their molecular mechanism of action, bisphosphonates can be divided into two pharmacological classes; nitrogen‐containing (N‐BPs) and non‐nitrogen‐containing bisphosphonates (non‐N‐BP). Both classes induce apoptosis but they evoke it differently; N‐BPs by inhibiting the intracellular mevalonate pathway and protein isoprenylation, and non‐N‐BPsviacytotoxic ATP analog‐type metabolites. N‐BPs are not metabolized to ATP analogs, but we report here that these bisphosphonates can induce formation of a novel ATP analog (ApppI) as a consequence of the inhibition of the mevalonate pathway in cells. We also investigated whether ApppI is involved in the apoptosis induced by N‐BPs.

Mass spectrometry and NMR were used to identify ApppI in N‐BP treated osteoclasts, macrophages and glioma cells. The potency of different bisphosphonates to promote ApppI production was tested in J774 macrophages. The effects of ApppI on ADP/ATP translocase in isolated mitochondria and its capability to induce apoptosis in osteoclasts were also studied.

ApppI production correlated well with the capacity of N‐BPs to inhibit mevalonate pathway. ApppI inhibited the mitochondrial ADP/ATP translocase and caused apoptosis in osteoclasts.

In conclusion, these findings provide the basis for a new mechanism of action for N‐BPs. Some of these very potent bisphosphonates, such as zoledronic acid, represent a third class of bisphosphonates that can act bothviathe inhibition of the mevalonate pathway and by the blockade of mitochondrial ADP/ATP translocase, which is known to be involved in the induction of apoptosis.

British Journal of Pharmacology(2006)147, 437–445. doi:10.1038/sj.bjp.0706628
Inhibition of autophosphorylation of epidermal growth factor receptor by small peptides in vitro
Authors: Abe Mineo , Kuroda Yoshihiro , Hirose Munetaka , Watanabe Yoshihiko , Nakano Minoru , Handa Tetsurou
Published: January 2006

Inhibition of uncontrolled epidermal growth factor receptor (EGFR) is one of the approaches for the treatment of breast and lung cancers. We designed oligopeptides consisting of amino‐acid sequences of the major (Y1068, Y1148, and Y1173) and minor (Y992) autophosphorylation sites of EGFR. These peptides may be exogenous substrates or pseudosubstrates that interfere with the autophosphorylation of EGFR. The effects of the peptides on autophosphorylation of EGFR were studied.

Purified EGFR was phosphorylated in vitro with EGF in the presence of various synthetic peptides. The phosphorylation level of EGFR was then evaluated after SDS–PAGE separation, followed by Western blot analysis with antiphosphotyrosine antibody.

Ac‐VPEYINQ‐NH2 (Y1068) and Ac‐DYQQD‐NH2 (Y1148) showed the most potent inhibitory effects, followed by Ac‐ENAEYLR‐NH2 (Y1173). These peptides at 4 mM suppressed phosphorylation to 30–50%.

Combination of the three kinds of peptides much more strongly inhibited autophosphorylation. The 50% inhibitory concentration (IC50) value was 0.5 mM as a mixture and was comparable to that of AG1478 (IC50, 0.3 mM) at 0.2 mM ATP.

Neither Ac‐DIYET‐NH2 or Ac‐KIYEK‐NH2, designed previously based on the amino‐acid sequence of an autophosphorylation site of insulin receptor, nor their related (Ac‐KIFMK‐NH2) or unrelated (Ac‐LPFFD‐NH2) peptides showed an inhibitory effect. These results suggest that the small peptides that originated from the autophosphorylation sites of EGFR interact solely with EGFR.

The peptides containing the sequences surrounding Y1068, Y1148, and Y1173 may be a promising seed for the development of therapeutic agents for breast and lung cancers.

British Journal of Pharmacology (2006) 147, 402–411. doi:10.1038/sj.bjp.0706634
Lifetime determination of fluorescence and phosphorescence of a series of oligofluorenes
Authors: Chi Chunyan , Im Chan , Wegner Gerhard
Published: January 2006

The photoluminescence (PL) properties of oligofluorenes with 2-ethylhexyl group in 9, 9′ position in solution and as thin films were investigated by time-resolved techniques at both room temperature and 77 K. The fluorescence lifetimes of the oligomers decrease with chain length. The lifetimes τ follow the relation τ=386+808(1∕n) (ps) where n is the number of fluorene units in the oligomer. Concentration and laser excitation energy dependences of PL spectra of the oligofluorenes are also given. Phosphorescence was observed for oligofluorenes in the frozen matrix of MTHF at 77 K. The lifetime of phosphorescence increases with increasing molecular length. Similar emission bands were observed for oligofluorenes with a central ketogroup. A lifetime analysis clearly reveals that the “green emission” of the oligomers free of ketogroups results from a phosphorescence with lifetime τ of 3 ms while the green emission from the keto-oligomer is a fluorescence from a charge transfer π-π* level of τ=8ns.
Desorption dynamics of deuterium molecules from the Si(100)-(3×1) dideuteride surface
Authors: Niida T. , Tsurumaki H. , Namiki A.
Published: January 2006

We measured polar angle (θ)-resolved time-of-flight spectra of D2 molecules desorbing from the Si(100)-(3×1) dideuteride surface. The desorbing D2 molecules exhibit a considerable translational heating with mean desorption kinetic energies of ≃0.25eV, which is mostly independent of the desorption angles for 0°⩽θ⩽30°. The observed desorption dynamics of deuterium was discussed along the principle of detailed balance to predict their adsorption dynamics onto the monohydride Si surface.
Spatial hydration structures and dynamics of phenol in sub- and supercritical water
Authors: Plugatyr Andriy , Nahtigal Istok , Svishchev Igor M.
Published: January 2006

The hydration structures and dynamics of phenol in aqueous solution at infinite dilution are investigated using molecular-dynamics simulation technique. The simulations are performed at several temperatures along the coexistence curve of water up to the critical point, and above the critical point with density fixed at 0.3g∕cm3. The hydration structures of phenol are characterized using the radial, cylindrical, and spatial distribution functions. In particular, full spatial maps of local atomic (solvent) density around a solute molecule are presented. It is demonstrated that in addition to normal H bonds with hydroxyl group of phenol, water forms π-type complexes with the center of the benzene ring, in which H2O molecules act as H-bond donor. At ambient conditions phenol is solvated by 38 water molecules, which make up a large hydrophobic cavity, and forms on average 2.39 H bonds (1.55 of which are due to the hydroxyl group-water interactions and 0.84 are due to the π complex) with its hydration shell. As temperature increases, the hydration structure of phenol undergoes significant changes. The disappearance of the π-type H bonding is observed near the critical point. Self-diffusion coefficients of water and phenol are also calculated. Dramatic increase in the diffusivity of phenol in aqueous solution is observed near the critical point of simple point-charge-extended water and is related to the changes in water structure at these conditions.
Phase of molecular ink in nanoscale direct deposition processes
Authors: Cho Narae , Ryu Seol , Kim Byeongju , Schatz George C. , Hong Seunghun
Published: January 2006

We report the first observation of a phase transition in a nanoscale direct deposition process. This transition involves the melting of molecular ink layers in dip-pen nanolithography, and it is observed by measuring the temperature dependence of the growth rate of the deposited pattern. The results are interpreted using a diffusion equation approach in conjunction with a “double-molecular-layer” model of the adsorbed molecules on the atomic force microscope tip. The theory provides a qualitative explanation for the dependence of the pattern growth rate on solvent and adsorbed water as well as on temperature.
Generation of “spiky” potential structures associated with multiharmonic electrostatic ion-cyclotron waves
Authors: Kim Su-Hyun , Merlino Robert L. , Ganguli Gurudas I.
Published: January 2006

The production of coherent, “spiky” electrostatic potential structures, similar to the spiky electric-field structures that have been observed in the Earth’s auroral region, is investigated in a magnetized Q machine plasma. These structures are associated with coherent multiharmonic electrostatic ion-cyclotron (EIC) waves in a current-free plasma having a localized region of ion flow shear (ion flow parallel to B with a gradient in the direction transverse to B). A multiharmonic EIC spectrum is detected in the region of ion flow shear when broadband electrostatic white noise is applied to the plasma column from an antenna. The time series of the potential fluctuations exhibit spiky structures with repetition rates near the ion-cyclotron frequency. Spiky structures can arise from linear combinations of phase-locked multiharmonic EIC waves when the amplitudes of the harmonic components are comparable to that of the fundamental EIC mode.
Experimental demonstration of a compact stellarator magnetic trap using four circular coils
Authors: Pedersen T. Sunn , Kremer J. P. , Lefrancois R. G. , Marksteiner Q. , Sarasola X. , Ahmad N.
Published: January 2006

An experimental demonstration of a compact stellarator magnetic trap created from four circular coils is presented. The coil manufacturing and assembly tolerances were on the order of 0.5–1%, far less stringent than most other stellarators. The simplicity, loose mechanical tolerances, and low cost of the trap design makes it feasible for stellarators to be used for a variety of novel physics experiments, in addition to their present use for magnetic confinement fusion. The experiment, the Columbia Non-neutral Torus, has several other desirable features such as no significant internal island chains and the lowest aspect ratio, A⩽1.9, of any stellarator built to date.
Incompatible strains associated with defects in nematic elastomers
Authors: Fried Eliot , Sellers Shaun
Published: January 2006

In a nematic elastomer the deformation of the polymer network chains is coupled to the orientational order of the mesogenic groups. Statistical arguments have derived the so-called neoclassical free energy that models this coupling. Here we show that the neoclassical model supplemented by the usual Frank energy predicts incompatible network strains associated with the formation of standard nematic textures. The incompatibility is measured by the Riemann curvature tensor, which we find to be nonzero for both radial hedgehog defects and escaped disclinations of strength +1 in circular cylinders. Analogous problems for conventional nonlinearly elastic solids do not possess solutions with such incompatibilities. Compatibility in nematic elastomers would require either more complicated nematic textures in elastomers than in conventional (polymeric and low molecular weight) liquid crystals or a free-energy density more complicated than the neoclassical expression.
Propagation of an electromagnetic wave in an atmospheric pressure plasma: Numerical solutions
Authors: Zhang Shu , Hu Xiwei , Jiang Zhonghe , Liu Minghai , He Yong
Published: January 2006

The propagation of an electromagnetic wave in an atmospheric pressure plasma (APP) layer is described numerically with an integral-differential wave equation. When the wave passes through the APP layer, the amplitude and phase of the transmission wave electric field are obviously modulated by the electron density and the collision frequency between the electrons and neutrals in the APP. The dependences of the wave behaviors, such as the phase shift, the coefficient of the transmission, reflection and absorption, on these APP layer characteristics are presented. Appleton’s equation is derived from the Wentzel–Kramers–Brillouin solution of the integral-differential wave equation and is compared with the numerical solution.
Structure of Au8: Planar or nonplanar?
Authors: Han Young-Kyu
Published: January 2006

We have studied the structures and stabilities of Au6 and Au8 at the density-functional theory (DFT) and ab initio correlated levels of theory. For Au8, our ab initio calculations predict the lowest Au8 isomer to be planar, in line with the DFT calculations.
Quantum Monte Carlo calculations of the dissociation energies of three-electron hemibonded radical cationic dimers
Authors: Gurtubay I. G. , Drummond N. D. , Towler M. D. , Needs R. J.
Published: January 2006

We report variational and diffusion quantum Monte Carlo (VMC and DMC) calculations of the dissociation energies of the three-electron hemibonded radical cationic dimers of He, NH3, H2O, HF, and Ne. These systems are particularly difficult for standard density-functional methods such as the local-density approximation and the generalized gradient approximation. We have performed both all-electron (AE) and pseudopotential (PP) calculations using Slater-Jastrow wave functions with Hartree-Fock single-particle orbitals. Our results are in good agreement with coupled-cluster CCSD(T) calculations. We have also studied the relative stability of the hemibonded and hydrogen-bonded water radical dimer isomers. Our calculations indicate that the latter isomer is more stable, in agreement with post-Hartree-Fock methods. The excellent agreement between our AE and PP results demonstrates the high quality of the PPs used within our VMC and DMC calculations.
The failure of the scattering angle cutoff for Coulomb interactions
Authors: Chang Yongbin
Published: January 2006

Careful study of the collision frequency for Coulomb interactions indicates that the traditional practice of making cutoff on a scattering angle is a failure. The only complete cutoff should be on velocity change. After making the velocity change as an independent variable, we obtain more satisfactory physical results for both Coulomb interactions and hard-sphere interactions. These physical results include collision frequency, dynamical friction coefficient, diffusion coefficients, energy exchange frequency, and arbitrary high-order Fokker–Planck coefficients. New special functions, Ql(k,u), are obtained for the expression of the arbitrary order Fokker-Planck coefficients for both Coulomb interactions and hard-sphere interactions. The combined results establish a valuable relationship between Coulomb interactions and hard-sphere interactions with a parameter α. The special functions, Ql(k,u), have some interesting properties which make it possible to analyze arbitrary order Fokker-Planck coefficients easily for the first time. A new constant D0 is introduced to replace Couloumb logarithm in the precise calculation of plasma equilibrium time. This new constant D0 is related with Arrhenius exponential constant defined in the collision theory for chemical reaction rate. A physical term H is proposed as the accumulative measure of a force to unify the concept of collision strength.
Nonlinear energy principle for model current sheets
Authors: Yoon Peter H. , Lui Anthony T. Y.
Published: January 2006

It is demonstrated on the basis of exact invariants of nonlinear Vlasov equation and model current sheets that the change in magnetic topology (i.e., reconnection) in a finite closed system leads to the conversion of magnetic-field energy to particle energy. It is also shown that the volume-averaged conversion efficiency diminishes as the spatial average is taken over larger and larger system size, while it increases when the system size becomes smaller. This finding may have an important implication for numerical simulation of reconnection processes under finite geometry.
Statistical mechanical theory for steady state systems. IV. Transition probability and simulation algorithm demonstrated for heat flow
Authors: Attard Phil
Published: January 2006

Two microscopic transition theorems are given for the probability of nonequilibrium work performed on a subsystem of a thermal reservoir along the trajectory in phase space of the subsystem. The resultant transition probability is applied to the case of heat flow down an applied temperature gradient. A combined molecular dynamics and Monte Carlo algorithm is given for such a nonequilibrium steady state. Results obtained for the thermal conductivity are in good agreement with previous Green-Kubo and nonequilibrium molecular dynamics results.
Cesium dimer spectroscopy on helium droplets
Authors: Ernst W. E. , Huber R. , Jiang S. , Beuc R. , Movre M. , Pichler G.
Published: January 2006

Visible absorption spectra of cesium-doped helium nanodroplets between 14 500 and 17600cm−1 were probed by laser-induced fluorescence. A strong absorption band peaking around 16700cm−1 is identified as Cs2 1(a)Σu+3−3Σg+3 transition. A broad unstructured band near 17520cm−1 is assigned as the Cs2 1(X)Σg+1−2Σu+1 transition. Explanations of the observations are discussed on the basis of ab initio potential curves calculated by Spies and Meyer [(unpublished)]. All spectra have been modeled using narrow Frank-Condon windows around the equilibrium internuclear distance of the lowest singlet and triplet states. Many observed absorption peaks of smaller intensities could be identified, some of which may be due to transitions of cesium trimers formed on the droplets.
Presheath structure of a dust-contaminated plasma
Authors: Li Yang-fang , Ma J. X.
Published: January 2006

The presheath structure of a dust-contaminated plasma is studied by taking into account the electron-impact ionization, the plasma loss due to the capture of electrons and ions by the dust grains, the ion-dust collisions, as well as the dust charge variations. It is shown that at the edge of the presheath with the sheath, there is a critical ion Mach number (the generalized Bohm criterion modified by the dust) which is exactly the same as that obtained from collisionless sheath model. On the other hand, depending on different equilibrium states of the bulk plasma, different connections between the bulk plasma and the presheath will be inferred. When the electron-impact ionization exactly balances the plasma loss, there is a smooth transition from the bulk plasma to the presheath, and both the ion velocity and the gradients of the velocity and density vanish at the edge of the presheath with the bulk plasma. When the plasma loss exceeds the ionization, the presheath starts at the point where the ion velocity equals the ambipolar diffusion velocity, i.e., the presheath profile is connected to the diffusion profile of the bulk plasma. When the ionization exceeds the plasma loss, the bulk plasma-presheath edge appears where the gradient of the ion density is zero but the gradient of the ion velocity is nonzero. For the plasma loss exceeding or being less than the ionization, numerical results reveal that the change of the dust density can result in opposite effects on the presheath profiles (shortening or broadening of the presheath region).
Blow-up, blow-up rate and decay of the solution of the weakly dissipative Camassa-Holm equation
Authors: Wu Shuyin , Yin Zhaoyang
Published: January 2006

In this paper, we mainly study several problems on the weakly dissipative periodic Camassa-Holm equation. At first, the local well-posedness of the equation is obtained by Kato’s theorem, a necessary and sufficient condition of the blow-up of the solution and some criteria guaranteeing the blow-up of the solution are established. Then, the blow-up rate of the solution is discussed. Moreover, we prove that the equation has global solutions and these global solutions decay to zero as time goes to infinite provided the potentials associated to their initial date are of one sign.
Intermittent turbulence and turbulent structures in a linear magnetized plasma
Authors: Carter T. A.
Published: January 2006

Strongly intermittent turbulence is observed in the shadow of a limiter in the large plasma device at UCLA [W. Gekelman et al., Rev. Sci. Instrum. 62, 2875 (1991)]. The amplitude probability distribution function of the turbulence is strongly skewed, with density depletion events (or “holes”) dominant in the high-density region and density-enhancement events (or “blobs”) dominant in the low-density region. Two-dimensional cross-conditional averaging shows that the blobs are detached, outward-propagating filamentary structures with a clear dipolar potential, while the holes appear to be part of a more extended turbulent structure. A statistical study of the blobs reveals a typical size of ten times the ion sound gyroradius and a typical velocity of one-tenth the sound speed.
Electroreflectance spectroscopy of Pt∕AlGaN∕GaN heterostructures exposed to gaseous hydrogen
Authors: Winzer A. T. , Goldhahn R. , Gobsch G. , Dadgar A. , Krost A. , Weidemann O. , Stutzmann M. , Eickhoff M.
Published: January 2006

The effect of hydrogen exposure on the properties of catalytic Pt∕AlGaN∕GaN heterostructures is investigated by electroreflectance spectroscopy. The technique is based on the analysis of the Franz–Keldysh oscillations observed above the AlGaN band gap and yields the electric-field strength in the AlGaN barrier. From these data, the hydrogen-induced changes of the two-dimensional electron gas (2DEG) concentration underneath the catalytic gate contact are quantitatively determined. The exposure increases the 2DEG concentration by 1.7×1012e/cm2 (1.3×1012e/cm2) and decreases the Schottky barrier height by 0.85V (0.65V) for barrier Al contents of 0.15 (0.20).
An ab initio potential surface describing abstraction and exchange for H+CH4
Authors: Zhang Xiubin , Braams Bastiaan J. , Bowman Joel M.
Published: January 2006

We report an ab initio-based global potential energy surface for H+CH4 that describes the abstraction and exchange reactions. The PES, which is invariant with respect to any permutation of five H atoms, is a fit to 20 728 electronic energies calculated using the partially spin-restricted coupled-cluster method (RCCSD(T)) with a moderately large basis (aug-cc-pVTZ). A first set of quasiclassical trajectory calculations using this PES are reported for the H+CD4→HD+CD3 reaction at collision energies of 0.65 and 1.52 eV and are compared to experiment and recent direct dynamics calculations done with density functional theory.
From K atom pairs to K atomic chains: A semiconducting 2×3 to metallic 2×1 transition on the β-SiC(100) c(4×2) surface
Authors: Derycke V. , Fonteneau P. , Hwu Y. K. , Soukiassian P.
Published: January 2006

We study the K∕β-SiC(100) c(4×2) surface by atom-resolved scanning tunneling microscopy and spectroscopy, and synchrotron radiation-based photoemission spectroscopy. At intermediate coverages, the K atoms are grouped by pairs around Si dimers at pedestal sites, in a 2×3 long-range ordering leaving 1∕3 of the pedestal sites unoccupied, while keeping the semiconducting c(4×2) surface unchanged as identified by tunneling through the K overlayer. At saturation, additional K atoms adsorb on remaining pedestal sites and act as atomic “contacts” between two K pairs, leading to K atom chain formation in a 2×1 metallic surface.
Metal-oxide-semiconductor capacitors on GaAs with high-k gate oxide and amorphous silicon interface passivation layer
Authors: Koveshnikov S. , Tsai W. , Ok I. , Lee J. C. , Torkanov V. , Yakimov M. , Oktyabrsky S.
Published: January 2006

We demonstrate the electrical properties of metal-oxide-semiconductor capacitors on molecular beam epitaxial GaAs in situ passivated with ultrathin amorphous Si (a-Si) layer and with ex situ deposited HfO2 gate oxide and TaN metal gate. Minimum thickness of the Si interface passivation layer of 1.5 nm is needed to prevent the Fermi level pinning and provide good capacitance-voltage characteristics with equivalent oxide thickness of 2.1 nm and leakage current of ⩽1.0mA∕cm2. Transmission electron microscopy analysis showed that the Si layer was oxidized up to 1.4 nm during ex situ processing while the interface between the GaAs and a-Si remained atomically sharp without any sign of interfacial reaction.
Gated spin transport through an individual single wall carbon nanotube
Authors: Nagabhirava B. , Bansal T. , Sumanasekera G. U. , Alphenaar B. W. , Liu L.
Published: January 2006

Hysteretic switching in the magnetoresistance of short-channel, ferromagnetically contacted individual single wall carbon nanotubes is observed, providing strong evidence for nanotube spin transport. By varying the voltage on a capacitively coupled gate, the magnetoresistance can be reproducibly modified between +10% and −15%. The results are explained in terms of wave vector matching of the spin polarized electron states at the ferromagnetic ∕ nanotube interfaces.
The influence of surface incorporated lime and gypsiferous by-products on surface and subsurface soil acidity. I. Soil solution chemistry
Authors: Wang H. L. , Bolan N. S. , Hedley M. J. , Horne D. J.
Published: January 2006

Lime, fluidised bed boiler ash (FBA), and flue gas desulfurisation gypsum
(FGDG) were incorporated in the top 50 mm of repacked columns of either an
Allophanic (the Patua sand loam) or an Ultic (the Kaawa clay loam) soil, at
rates containing calcium equivalent to 5000 kg/ha of
CaCO3. Each column was leached with 400 mm of water.
After leaching, the columns were sliced into sections for chemical analysis.
In the columns of the variable-charged, allophanic Patua soil,
topsoil-incorporated FBA ameliorated top and subsurface soil acidity through
liming and the ‘self-liming effect’ induced by sulfate sorption,
respectively. The soil solution pH of the top and subsurface layers of the
Patua soil were raised to pH 6·40 and 5·35, respectively, by the
FBA treatment, compared with pH 4·80 and 4·65, respectively, in
the control treatment. Consequently, phytotoxic labile monomeric aluminium
(Al) concentration in the soil solution of the FBA treatment was reduced to
<0·1 µM Al, compared with 8–64 µM Al in the
untreated control. FGDG had a similar ‘self-liming effect’ on
subsurface of the Patua soil, but not the topsoil. Whereas FBA raised the pH
of the Kaawa topsoil, no ‘self-liming effect’ of subsurface soil
by sulfate sorption was observed on the Kaawa subsurface soil, which is
dominated by permanently charged clay minerals. Application of FBA and FGDG to
both soils, however, caused significant leaching of native soil
Mg2+ and K+. These nutrients were
displaced from the exchange sites by the relatively high concentration of
Ca2+ released from dissolution of gypsum.
The influence of surface incorporated lime and gypsiferous by-products on surface and subsurface soil acidity. II. Root growth and agronomic implications
Authors: Bolan N. S. , Wang H. L. , Hedley M. J. , Horne D. J.
Published: January 2006

Lucerne (Medicago sativa. L) root elongation in acid
soils amended by gypsiferous coal combustion by-products was investigated in a
glasshouse study. Lime, fluidised bed boiler ash (FBA), and flue gas
desulfurisation gypsum (FGDG) were mixed into the surface 50 mm of either an
Allophanic (the Patua sand loam) or an Ultic (the Kaawa clay loam) soil
column, at rates containing calcium equivalent to 5000 kg/ha of
CaCO3. Lucerne was grown on each column after it was
leached with 400 mm of water. Whereas the lime treatment had no effect on root
elongation in the acidic subsurface of the Patua soil, the FBA and FGDG
treatments significantly improved lucerne root penetration into the subsurface
soil (P < 0·05). This was due to the
‘self-liming effect’ induced by sulfate adsorption. Regression
analysis indicated that the molar ratio of labile monomeric aluminium and
calcium in soil solution (Al : Ca) was a good indicator of the degree of root
growth into subsurface soil layers
(R2= 0·94). In
contrast, topsoil incorporated amendments did not influence root penetration
into the acidic subsurface of the Kaawa soil, which is dominated by
permanently charged clay minerals.
The ‘self-liming effect’ caused by gypsum application is not a
sustainable practice. Lime should be applied to neutralise the topsoil
acidity, when gypsum is used as subsurface soil acidity ameliorant. FBA, which
contains both lime and gypsum, can meet these requirements.
The influence of the soil matrix on nitrogen mineralisation and nitrification III. Predictive utility of traditional variables and process location within the pore system
Authors: Strong D. T. , Sale P. W. G. , Helyar K. R.
Published: January 2006

Regression analysis was used to examine the importance of organic nitrogen
(%N), soil water content (θv), soil pH, and C: N ratio for
predicting N mineralisation in a small field plot. Undisturbed soil cubes
(c. 1·7 cm3) were collected
from the soil surface and received treatments of drying and rewetting, urea,
substrate derived from clover leachate, or no amendment, and were incubated at
either –10 or –30 kPa for 20 days.
The data confirm the hypothesis that within a small field plot, θv and
%N explain most of the variation in net N mineralisation and
nitrification. The pore size classes of 0·6–10 and 10–30
µm made disproportionately small and large contributions to N
mineralisation, respectively, apparently due to non-uniform distribution of
organic N through the pore system. When soluble N substrate was added to the
soils, both these pore classes appeared to support mineralisation. We
concluded that prior to sampling, the microbial biomass had been more active
in the pores 0·6–10 µm, and had nearly exhausted the
organic substrates in this pore class, whereas this was not so for the
10–30 µm pore class. Drying and rewetting increased the importance
of %N as a predictor of N mineralisation, probably because this
treatment disrupted physical protective mechanisms of organic N. Soil pH was
generally not a useful predictor of N mineralisation and often seemed to be a
dependent rather than an independent variable in relation to nitrification.
Neither was C: N ratio a useful predictor of N transformation processes, and
this was probably related to physical regulatory mechanisms in the soil.