bluuebunny/crossref_metadata_2025 huggingface dataset:
Model density approach to the Kohn–Sham problem: Efficient extension of the density fitting technique
Authors: Birkenheuer Uwe , Gordienko Aleksei B. , Nasluzov Vladimir A. , Fuchs‐Rohr Monika K. , Rösch Notker
Published: January 2005

We present a novel procedure for treating the exchange‐correlation contributions in the Kohn–Sham procedure. The approach proposed is fully variational and closely related to the so‐called “fitting functions” method for the Coulomb Hartree problem; in fact, the method consistently uses this auxiliary representation of the electron density to determine the exchange‐correlation contributions. The exchange‐correlation potential and its matrix elements in a basis set of localized (atomic) orbitals can be evaluated by reusing the three‐center Coulomb integrals involving fitting functions, while the computational cost of the remaining numerical integration is significantly reduced and scales only linearly with the size of the auxiliary basis. We tested the approach extensively for a large set of atoms and small molecules as well as for transition‐metal carbonyls and clusters, by comparing total energies, atomization energies, structure parameters, and vibrational frequencies at the local density approximation and generalized gradient approximation levels of theory. The method requires a sufficiently flexible auxiliary basis set. We propose a minimal extension of the conventional auxiliary basis set, which yields essentially the same accuracy for the quantities just mentioned as the standard approach. The new method allows one to achieve substantial savings compared with a fully numerical integration of the exchange‐correlation contributions. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Elongation method with cutoff technique for linear SCF scaling
Authors: Korchowiec Jacek , Gu Feng Long , Imamura Akira , Kirtman Bernard , Aoki Yuriko
Published: January 2005

The elongation method uses the concept of locality and works in a regionally localized molecular orbital basis set. In this method the system is partitioned into several frozen fragments and an active one. If the coupling between a given frozen fragment and the active space is small enough, one can develop a cutoff scheme for effectively discarding the former in all further calculations. At the Hartree–Fock level many two‐electron integrals are thereby eliminated, leading to a reduction in self‐consistent field computation time. In test calculations on four polyglycine conformers, with an appropriate default threshold for coupling, the cutoff error is very small and/or comparable to that of a normal elongation calculation. On the other hand, the computation time for 20 residues is a factor of 5 less than that of a normal Hartree–Fock treatment and scales linearly (or even sublinearly) with the number of residues. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
MCD of non‐aromatic cyclic π‐electron systems. Part 6: Pentalenes and heptalenes
Authors: Fleischhauer Jörg , Raabe Gerhard , Klingensmith Kenneth A. , Höweler Udo , Chatterjee Prabir K. , Hafner Klaus , Vogel Emanuel , Michl Josef
Published: January 2005

The magnetic circular dichroism (MCD) spectra of several stable derivatives of pentalene (1) and heptalene (2) have been recorded. The lowest energy transition (from the ground to the S state in perimeter model nomenclature) is extremely weak in MCD and in absorption. The sign patterns of the B terms for the first three strong transitions—N1, N2, P1—in the order of increasing energy, are −−+ for 1 and ++− for 2. These findings are in perfect agreement with numerical results obtained at the SACCI level and with expectations based on the perimeter model of Parts 1–4 of this series, both of which lead to the conclusion that the magnetic mixing of the S excited state with the ground state is dominant. This is an extremely rare situation for an organic molecule, in which B term signs are normally determined by the mutual magnetic mixing of excited states. It can be expected to occur in other conjugated systems derived from 4N‐electron perimeters that have a low‐energy first excitation, which is of intrashell nature in the perimeter model and therefore is magnetic‐dipole allowed. In contrast, all low‐energy transitions in the much more common systems derived from (4N + 2)‐electron perimeters are of intershell nature and are magnetic‐dipole forbidden. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Can the Fulleride superconducting model (FSM) be extended?
Authors: Squire R. H.
Published: January 2005

The Fulleride superconducting model (FSM) is based on the existence of an electron (or Cooper) pair density wave localized on a single Fulleride molecule. Interaction of the wave with itinerant electrons at low temperature creates a pseudo‐gap above the superconducting state. In addition, the interaction of the electron and the bosonic pair create a net attraction between two Fulleride molecules resulting in an intermolecular Cooper pair. This pairing interaction appears to have all the aspects of a spin liquid. This study extends the model to high‐temperature superconductors and suggests that superconductivity may exist with considerably fewer molecules than in BCS theory. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
A method for carbon stable isotope analysis of methyl halides and chlorofluorocarbons at pptv concentrations
Authors: Archbold Marie E. , Redeker Kelly R. , Davis Simon , Elliot Trevor , Kalin Robert M.
Published: January 2005

A pre‐concentration system has been validated for use with a gas chromatography/mass spectrometry/isotope ratio mass spectrometer (GC/MS/IRMS) to determine ambient air 13C/12C ratios for methyl halides (MeCl and MeBr) and chlorofluorocarbons (CFCs). The isotopic composition of specific compounds can provide useful information on their atmospheric budgets and biogeochemistry that cannot be ascertained from abundance measurements alone. Although pre‐concentration systems have been previously used with a GC/MS/IRMS for atmospheric trace gas analysis, this is the first study also to report system validation tests. Validation results indicate that the pre‐concentration system and subsequent separation technologies do not significantly alter the stable isotopic ratios of the target methyl halides, CFC‐12 (CCl2F2) and CFC‐113 (C2Cl3F3). Significant, but consistent, isotopic shifts of −27.5‰ to −25.6‰ do occur within the system for CFC‐11 (CCl3F), although the shift is correctible. The method presented has the capacity to separate these target halocarbons from more than 50 other compounds in ambient air samples. Separation allows for the determination of stable carbon isotope ratios of five of these six target trace atmospheric constituents within ambient air for large volume samples (≤10 L). Representative urban air analyses from Belfast City are also presented which give carbon isotope results similar to published values for 13C/12C analysis of MeCl (−39.1‰) and CFC‐113 (−28.1‰). However, this is the first paper reporting stable carbon isotope signatures for CFC‐11 (−29.4‰) and CFC‐12 (−37.0‰). Copyright © 2005 John Wiley & Sons, Ltd.
Carbon isotope analyses of cellulose using two different on‐line techniques (elemental analysis and high‐temperature pyrolysis)—a comparison
Authors: Knöller Kay , Boettger Tatjana , Weise Stephan M. , Gehre Matthias
Published: January 2005

Even though the recent development in on‐line methods for the stable isotope determination in cellulose has led to a significant increase in sample throughput and decrease in sample preparation expenditure, there still is a large potential for optimizing the analytical procedures by simultaneously measuring the isotope ratios of two or even more elements. Therefore, the main objective of this study was to answer the question whether high‐temperature pyrolysis (HTP) is a suitable and reliable technique for the determination of the carbon isotopic composition of cellulose simultaneously during the well‐known conventional oxygen isotope analysis. This study shows that HTP of cellulose is a technique that can produce reasonable δ13C values, matching the requirements of most research problems related to paleoclimatology. The reproducibility of the delta values for 13C/12C is better than 0.2‰. Some deficiencies of the method are related to the incomplete conversion of the organic carbon in the sample to carbon monoxide. A clear isotope effect seems to be related to the non‐statistical conversion of the carbon in the cellulose to CO. The extent of this effect appears to be controlled by the relative proportion of crystallized and amorphous matter in the cellulose structure. Those deficiencies can be eliminated by using an appropriate normalization and by applying the principles of identical treatment for reference materials and samples. In general, a very good agreement is achieved for carbon isotope values determined by HTP and elemental analysis (EA). Copyright © 2005 John Wiley & Sons, Ltd.
The carbon isotope composition of CO2 respired by trunks: comparison of four sampling methods
Authors: Damesin C. , Barbaroux C. , Berveiller D. , Lelarge C. , Chaves M. , Maguas C. , Maia R. , Pontailler J.‐Y.
Published: January 2005

The 13C natural abundance of CO2 respired by plants has been used in the laboratory to examine the discrimination processes that occur during respiration. Currently, field measurements are being expanded to interpret the respiration δ13C signature measured at ecosystem and global levels. In this context, forests are particularly important to consider as they represent 80% of the continental biomass. The objective of this investigation was to compare four methods of sampling the CO2 respired by trunks for the determination of its carbon isotope composition: three in situ methods using chambers placed on the trunk, and one destructive method using cores of woody tissues. The in situ methods were based either on a Keeling plot approach applied at the tissue level or on an initial flush of the chamber with nitrogen or with CO2‐free air. In parallel, we investigated the possibility of an apparent discrimination during tissue respiration by comparing the δ13C signature of the respired CO2 and that of the organic matter. The study was performed on six tree species widely distributed in temperate and mediterranean areas. The four methods were not significantly different when overall means were considered. However, considering the individual data, the Keeling plot approach and the nitrogen flush methods gave fairly homogeneous results, whereas the CO2‐free air method produced more variable results. The core method was not correlated with any of the chamber methods. Regardless of the methodology, the respired CO2 generally was enriched in 13C relative to the total organic matter. This apparent enrichment during respiration was variable, reaching as much as 3–5‰. This study showed that, on the whole, the different sampling techniques gave similar results, but one should be aware of the variability associated with each method. Copyright © 2005 John Wiley & Sons, Ltd.
Halogeno‐substituted 2‐aminobenzoic acid derivatives for negative ion fragmentation studies of N‐linked carbohydrates
Authors: Harvey David J.
Published: January 2005

Negative ion electrospray mass spectra of high‐mannose N‐linked glycans derivatised with 2‐aminobenzoic acids and ionised from solutions containing ammonium hydroxide gave prominent [M–H]− ions accompanied by weaker [M–2H]2− ions. Fragmentation of both types of ions gave prominent singly charged glycosidic cleavage ions containing the derivatised reducing terminus and ions from the non‐reducing terminus that appeared to be products of cross‐ring cleavages. Differentiation of these two groups of ions was conveniently achieved in a single spectrum by use of chloro‐ or bromo‐substituted benzoic acids in order to label ions containing the derivative with an atom with a distinctive isotope pattern. Fragmentation of the doubly charged ions gave more abundant fragments, both singly and doubly charged, than did fragmentation of the singly charged ions, but information of chain branching was masked by the appearance of prominent ions produced by internal cleavages. Copyright © 2005 John Wiley & Sons, Ltd.
Characteristic fragmentation behavior of some glucuronide‐type triterpenoid saponins using electrospray ionization tandem mass spectrometry
Authors: Li Bin , Abliz Zeper , Fu Guangmiao , Tang Meijun , Yu Shishan
Published: January 2005

The fragmentation behavior of some glucuronide‐type triterpenoid saponins from Symplocos chinensis, and their analogues escin Ia and Ib, were investigated by positive ion electrospray ionization tandem mass spectrometry using a quadrupole linear ion trap mass spectrometer. The fragmentation patterns of these saponins significantly changed in accordance with structural variations in the glucuronyl residue of the oligosaccharide chain. It was found that the carboxyl group and hydroxyl group at the C‐3′ position of the glucuronyl residue were the key sites for determining the fragmentation behavior of these compounds. When the carboxyl group was esterified, only the C2α ion, and no B2α ion, and cationized aglycone were observed. When the hydroxyl group at C‐3′ was acylated, the inherent cross‐ring cleavage was hindered. However, glycosidic cleavages always occurred, regardless of the crucial structural variations. The results of the present studies can benefit the determination of trace triterpenoid saponins of this type in crude plant extracts, and also provide background information to aid the structural investigations of similar glycoconjugates. Copyright © 2005 John Wiley & Sons, Ltd.
Divergence between community psychologists in academic and nonacademic settings: A closer look at the implications
Authors: Elias Maurice J. , Dalton James H. , Franco Robert , Howe George W.
Published: January 2005

Conclusion

The ecological principle of interdependence has been a guiding theme in our research and conceptualization. For the development of community psychology, academic and applied interest and networks must be integrated in ways which value the views and resources of both groups. This is the focus of Kelly's (1984) remarks. The dynamic interplay of ideas, data, and practices is likely to facilitate the collaboration between researchers and setting inhabitants which Trickett (1984) describes as the distinctive quality of community psychology. Common pathways of information exchange, joint responsibility for training future members of the field, and mutually enhancing role relationships are needed. Current channels of communication provide little ease of access or incentives for participation by psychologists in nonacademic settings. It thus becomes the reponsibility of all concerned community psychologists to use their organizational skills to redress this harmful imbalance (Kelly, 1984). For this to occur, however, we must take the initial steps of frankly recognizing differences in our folkways and organizational constraints, while also emphasizing our common values and assets. The largest threat to the field is external constraints from university and clinical service settings on the work that represents community psychology (Elias et al., 1984). If we are dividedor uninformed in the face of these environmental presses, we will never create the adaptive niche that community psychology needs to survive.
A computer checked algebraic verification of a distributed summation algorithm
Authors: Groote Jan Friso , Monin François , Springintveld Jan
Published: January 2005

We present an algebraic verification of Segall’s propagation of information with feedback algorithm and we report on the verification of the proof using the PVS system. This algorithm serves as a nice benchmark for verification exercises (see [2, 8, 17]). The verification is based on the methodology presented in [7] and demonstrates its suitability to deliver mechanically verifiable correctness proofs of highly nondeterministic distributed algorithms.
A useful dialogue? Habermas and International Relations
Authors: Diez Thomas , Steans Jill
Published: January 2005

It is now more than twenty years since Jürgen Habermas's work was first referred to in International Relations (IR) theory. Along with many other continental philosophers and social theorists, Habermas was initially mobilised in the critique of positivism, and in particular neorealism, in IR theory. As such, the interest in Habermas and IR must be located in the first instance within the context of the fourth debate. This Forum section of the Review provides us with the opportunity to take stock and ask whether the dialogue between Habermas and IR has, thus far, been useful in providing new conceptual and methodological tools to analyse international politics and in inspiring new research agendas in IR. We also ask whether the role that dialogue plays within Habermas's work has been useful in formulating a critical theory of international relations.
Dialogic politics and the civilising process
Authors: Linklater Andrew
Published: January 2005

Recent debates about Habermas's conception of dialogic politics have focused on whether its commitment to ethical universalism has an emancipatory potential or threatens the assimilation of non-liberal forms of life within exclusionary Western cultural frameworks. One way of contributing to this unfinished debate is to ask whether discourse ethics contributes to the modern ‘civilising process’, as Norbert Elias defined that term. All societies, according to Elias, have civilising processes or ways of trying to solve the problem of how persons can satisfy basic needs without ‘destroying, frustrating, demeaning or in other ways harming each other time and time again in their search for this satisfaction’. This formulation invites the question of whether or not the discourse theory of morality is the best available means of extending the civilising process in global politics.
Theoretical paradise – empirically lost? Arguing with Habermas
Authors: Deitelhoff Nicole , Müller Harald
Published: January 2005

Jürgen Habermas' thinking gained influence within the German International Relations (IR) community in the early 1990s. At the core of the so-called ‘ZIB-debate’ was the controversy whether rationalist theory can explain interstate cooperation. Constructivists accused rationalists of ignoring communication, language and reason, thereby leaving a logical gap in their analyses of interstate cooperation. This gap exists between the plausible motivation for states to cooperate and their actual achievement of cooperation. Rationalist approaches assume that actors face problematic, interdependent situations, in which they can only optimise their preferences by collaboration. Such situations involve a plausible motivation for actors to cooperate but they are not a sufficient condition to ensure that cooperation will actually happen. What is missing is a theoretical link between a general motivation to cooperate and its realisation, given that rationalist theory, following realism, regularly assumes a dangerous anarchical environment with its daunting security dilemma. These circumstances make cooperation risky and should normally work as a show-stopper for nation-states to collaborate.
The Frankfurt School and International Relations' on the centrality of recognition
Authors: Haacke Jürgen
Published: January 2005

The works of Jürgen Habermas have amounted to an inspiration to many within IR. His writings on communicative rationality and communicative action are widely regarded as a useful counterpoint to the emphasis on instrumental rationality and strategic action. Also, Habermas has greatly influenced the development of Critical International Theory. However, as other contributions in this Forum demonstrate, IR scholars have at times found it difficult to apply Habermas to service their specific social scientific inquiries. In particular, it has been difficult to unequivocally locate communicative action in diplomatic exchanges or international negotiations. It is partly for this reason that the contributions of the so-called ‘Third Generation’ of Frankfurt School scholars have attracted increasing interest. Axel Honneth's attempts to reconstruct insights in relation to the struggle for recognition into a social theory (with critical intent) have to date been of particular importance in this context. Indeed, given the perceived difficulties in ‘applying’ Habermas, there appears to be an emerging trend to end the honeymoon with Habermas in favour of a reorientation toward Honneth.
The critical social theory of the Frankfurt School, and the ‘social turn’ in IR
Authors: Weber Martin
Published: January 2005

Critical theory in the Frankfurt School mould has made various inroads into IR theorising, and provided many a stimulus to attempts at redressing the ‘positivist’ imbalance in the discipline. Many of the conceptual offerings of the Frankfurt School perspective have received critical attention in IR theory debates, and while these are still ongoing, the purpose of this discussion is not to attempt to contribute by furthering either methodological interests, or politico-philosophical inquiry. Instead, I focus on the near omission of the social-theoretic aspect of the work especially of Juergen Habermas. I argue that a more in-depth exploration of critical social theory has considerable potential in the context of the ‘social turn’ in IR theory. The lack of attention to this potential is arguably due in part to the importance of Habermas' contribution to cosmopolitan normative theory, and the status held by the cosmopolitan-communitarian debate as a key site of critical IR debate for many years throughout the 1990s. The productivity of the Habermasian conception of the discourse theory of morality within this set of concerns has been obvious, and continues.
On the stabilization of a biped vertical posture in single support using internal torques
Authors: Aoustin Yannick , Formal'sky Alexander
Published: January 2005

We consider the problem of the stabilization in single support of the vertical posture for a two-link, a three-link, and a five-link planar biped without feet. The control torques are applied in the inter-link joints only. Thus, our objects are under-actuated systems. The control laws are designed, using the biped linear models and their associated Jordan forms. The feedback is synthesized to suppress the unstable modes. The limits imposed on the torques are taken into account explicitly. Thus, the feedback laws with saturation are designed. The numerical investigations of the nonlinear models with the designed control laws are presented.
An improved energy stability margin for walking machines subject to dynamic effects
Authors: Garcia Elena , de Santos Pablo Gonzalez
Published: January 2005

Several static and dynamic stability criteria have been defined in the course of walking-robot history. Nevertheless, previous work on the classification of stability criteria for statically stable walking machines (having at least four legs) reveals that there is no stability margin that accurately predicts robot stability when inertial and manipulation effects are significant. In such cases, every momentum-based stability margin fails. The use of an unsuitable stability criterion yields unavoidable errors in the control of walking robots. Moreover, inertial and manipulation effects usually appear in the motion of these robots when they are used for services or industrial applications. A new stability margin that accurately measures robot stability considering dynamic effects arising during motion is proposed in this paper. The new stability margin is proven to be the only exact stability margin when robot dynamics and manipulation forces exist. Numerical comparison has been conducted to support the margin's suitability. Stability-level curves are also presented on the basis of a suitable stability margin to control the trajectory of the center of gravity during the support phase.
Design of an omni-directional mobile microrobot (OMMR-I) for a micro-factory with 2 mm electromagnetic micromotors
Authors: Li Zhenbo , Chen Jiapin , Feng Jianzhi
Published: January 2005

In this paper, the design and control of an omni-directional mobile microrobot are described for micro-assembling in a micro-factory. A unique locomotion mechanism composed of three special castors units is proposed. The castor consists of two coaxial conventional wheels, connected to the chassis and connected with each other by a set micro-gears. The microrobot is approximately 8 mm in length, 6 mm in width and 6 mm in height. Its kinematics and characteristics are analyzed. Experimental results from a prototype of a microrobot are presented, which demonstrates the feasibility of building an omni-directional microrobot with micromotor and special castors.
Model-based optimal attitude and positioning control of small-scale unmanned helicopter
Authors: Shin Jinok , Nonami Kenzo , Fujiwara Daigo , Hazawa Kensaku
Published: January 2005

In this paper, we propose a model-based control system design for autonomous flight and guidance control of a small-scale unmanned helicopter. Small-scale unmanned helicopters have been studied by way of fuzzy and neural network theory, but control that is not based on a model fails to yield good stabilization performance. For this reason, we design a mathematical model and a model-based controller for a small-scale unmanned helicopter system. In order to realize a fully autonomous small-scale unmanned helicopter, we have designed a MIMO attitude controller and a trajectory controller equipped with a Kalman filter-based LQI for a small-scale unmanned helicopter. The design of the trajectory controller takes into consideration the characteristics of attitude closed-loop dynamics. Simulations and experiments have shown that the proposed scheme for attitude control and position control is very useful.
Early Adoption Technology Performance Impact: AIS on the St. Lawrence Seaway
Authors: Grabowski Martha , Dhami Hemil
Published: January 2005

An Automatic Identification System (AIS) was implemented in the St. Lawrence Seaway during 2003. This paper reports the results of a trial conducted pre- and post-AIS implementation to examine the impact of AIS adoption in a safety-critical system. Analysis of the impact on three types of operators, ship's masters, mates and shore-based traffic management system operators showed that overall AIS significantly improved voyage plan monitoring, contributed to improved monitoring vigilance and offered significant aid to decision making. Recommendations include follow-on studies to include a steady state evaluation of the technology impact once the system is mature and a broadening of the pool of subjects to include a less experienced, more international and less well educated group of operators.
Incorporating Landmarks in Driver Navigation System Design: An Overview of Results from the REGIONAL Project
Authors: May Andrew J. , Ross Tracy , Bayer Steven H.
Published: January 2005

This paper presents an overview of results from the two year REGIONAL project. The aims of REGIONAL were to undertake research to enable landmarks to be an integral feature of future vehicle navigation systems. Results from the project, including five empirical road-based trials, are summarised. The main findings were: landmarks were widely used by drivers as key navigation cues; the incorporation of good landmarks within navigation instructions has the potential to considerably enhance vehicle navigation systems; although a wide range of landmarks are potentially useful to a driver, only a limited set, which displayed key characteristics, were consistently effective as navigation cues.
Airborne Collision Avoidance Systems and Air Traffic Management Safety
Authors: Brooker Peter
Published: January 2005

A new ICAO Policy on Airborne Collision Avoidance Systems is needed, which recognizes it to be an integrated part of the air traffic management system's safety defences; and that should be fully included in hazard analyses for the total system's design safety targets.
Collision Rules For High-Speed Craft
Authors: Pike Dag
Published: January 2005

Re-visiting the requirement to introduce amended collision regulations to meet the developing threat in encounters between high-speed craft and slower, mainly smaller vessels. This paper looks at the requirements of different types of encounter and the ability to identify high-speed craft through AIS. It introduces proposed changes to the Colregs that could help to reduce the perceived threat to small, slow craft.
Social Justice and Disabled People: Principles and Challenges
Authors: Goodlad Robina , Riddell Sheila
Published: January 2005

Social justice is a policy aim of the UK Labour government. This paper considers the applicability of the concept to disability, seeking to establish principles for conceptualising social justice and disability and considering the nature of the challenges for public policy and society posed by this conceptualisation. The paper considers how disability is implicated in two types of claims about the source of social injustice: those concerned with socially constructed differences between people; and those arising from material inequalities. Appropriate values underpinning alternative conceptions of social justice are discussed and tensions in policymaking considered.
The Development of Direct Payments in the UK: Implications for Social Justice
Authors: Riddell Sheila , Pearson Charlotte , Jolly Debbie , Barnes Colin , Priestley Mark , Mercer Geof
Published: January 2005

Direct payments have been heralded by the disability movement as an important means to achieving independent living and hence greater social justice for disabled people through enhanced recognition as well as financial redistribution. Drawing on data from the ESRC funded project Disabled People and Direct Payments: A UK Comparative Perspective, this paper presents an analysis of policy and official statistics on use of direct payments across the UK. It is argued that the potential of direct payments has only partly been realised as a result of very low and uneven uptake within and between different parts of the UK. This is accounted for in part by resistance from some Labour-controlled local authorities, which regard direct payments as a threat to public sector jobs. In addition, access to direct payments has been uneven across impairment groups. However, from a very low base there has been a rapid expansion in the use of direct payments over the past three years. The extent to which direct payments are able to facilitate the ultimate goal of independent living for disabled people requires careful monitoring.
Disability, Genetics and Global Justice
Authors: Shakespeare Tom
Published: January 2005

Genetic developments are viewed with distrust by the disability rights community. But the argument that genetic screening promotes social injustice is not straightforward. Disabled people are affected by both the problems of impairment and the problems of disability. Preventing impairment should be a priority as well as preventing disability. Questions of social justice arise if biomedical approaches are prioritized at the cost of structural changes in society. They also arise when disabled people do not have access to genetic medicine. On a global scale, the priorities for impairment prevention are basic healthcare, not high technology medicine.
Social Justice and Public Policy
Authors: Goodlad Robina , Riddell Sheila
Published: January 2005

1 Key texts A basic introduction to political philosophy, covering social justice and related issues well is: Kymlicka, W. (2002), Contemporary political philosophy: an introduction, 2nd edition, Oxford: Oxford University Press.
Polar vortex controls coupling of North Atlantic Ocean and atmosphere
Authors: Graf Hans‐F. , Walter Katrin
Published: January 2005

The structure of the North Atlantic leading atmospheric winter variability mode strongly depends on the state of the polar stratospheric vortex. If the polar vortex is strong, one teleconnection pattern emerges in the upper troposphere, while two mostly independent ones appear when the vortex is weak. The anomaly patterns associated with the different polarities of these modes show strong differences in the wind fields and in the correlation of atmospheric variability with the sea surface temperature of the North Atlantic. Only when the polar vortex is strong, does a basin‐wide tripole correlation pattern exist between tropospheric variability and sea surface temperature. Under weak vortex conditions one of the variability modes correlates with the subtropical, the other with the subpolar gyre. These results suggest that a NAO index based on near surface pressure that fails to account for the state of the polar vortex is a suboptimal representation of the tropospheric circulation variability.
Implications of persistent ice supersaturation in cold cirrus for stratospheric water vapor
Authors: Jensen E. , Pfister L.
Published: January 2005

Recent measurements made near the tropical tropopause during the NASA Cirrus Regional Study of Tropical Anvils and Cirrus Layers ‐ Florida Area Cirrus Experiment (CRYSTAL‐FACE) indicate persistent ice saturation ratios (si) of about 1.2–1.3 in cold ice clouds (T < 200 K) even when the ice surface area is substantial [Gao et al., 2004]. These observations challenge the conventional thinking that any water vapor in excess of ice saturation should be depleted by crystal growth given sufficient time. Here we use model simulations to evaluate the impact of this steady‐state ice supersaturation on cirrus formed in situ within the tropical tropopause layer and water vapor fluxes across the tropical tropopause. We show that cirrus occurrence frequencies are unexpectedly increased, and we estimate an increase of about 0.5–1 ppmv in the water vapor concentration in air entering the stratosphere. Inclusion of the enhanced in‐cloud supersaturation in our simulations improves agreement with satellite measurements of water vapor.
Nonlinear electron heating by resonant shear Alfvén waves in the ionosphere
Authors: Lu J. Y. , Rankin R. , Marchand R. , Tikhonchuk V. T.
Published: January 2005

Ionospheric electron heating by resonant standing shear Alfvén waves in Earth's magnetosphere is investigated. It is demonstrated that in field line resonances (FLRs), electron heating by Alfvén waves produces ionization and large changes in the ionospheric Pedersen conductivity. This leads to a strong feedback effect on the FLR amplitude, along with narrow localization in latitude. Analysis and computer simulations performed with a 2D finite element MHD code, indicate that the primary mechanisms responsible for variations in the electron temperature are ohmic heating by the electron component of the Pedersen current, and electron cooling due to ionization losses and collisions with neutrals. It is shown that electron heating can be quantitatively more important than direct collisional ionization by precipitating electrons. The latter can reduce dissipation losses by at most a factor of two.
Texture, spatial distribution, and rate of reservoir sedimentation within a highly erosive, cultivated watershed: Grenada Lake, Mississippi
Authors: Bennett Sean J. , Rhoton Fred E. , Dunbar John A.
Published: January 2005

While more than 75,000 dams nationwide have served a multitude of purposes over the past 50 years, current emphasis is being placed on decommissioning those aged infrastructures considered environmentally harmful. Grenada Lake, a relatively large flood control reservoir in Mississippi, is located in a highly erodible region of the United States and is fed by historically unstable stream channels. Through a variety of stratigraphic analyses, postimpoundment sediments are identified in the reservoir, showing that the lake has lost a nominal 3% of its flood storage capacity since its inception in 1954. A simple sediment budget constructed for the Yalobusha River's contribution of channel‐derived sediments shows that about 76% of this sediment remains stored upstream, about 16% is stored in the reservoir, and about 8% has exited the lake. Sediment delivery ratios, known to be low for relatively large watersheds, appear to be unaffected by upstream channel instabilities and aggressive channelization projects.
Cyclophilin C-Associated Protein and Cyclophilin C mRNA are Upregulated in Penumbral Neurons and Microglia after Focal Cerebral Ischemia
Authors: Shimizu Tatsuya , Imai Hideaki , Seki Koji , Tomizawa Shinichiro , Nakamura Mitsunobu , Honda Fumiaki , Kawahara Nobutaka , Saito Nobuhito
Published: January 2005

Immunophilin ligands, such as cyclosporin A and FK506, have neuroprotective effects in experimental stroke models, although the precise mechanism is unclear. Cyclophilin C-associated protein (CyCAP) is a natural cellular ligand for the immunophilin, cyclophilin C, and has a protective effect against endotoxins by downmodulating the proinflammatory response. Expressions of CyCAP and cyclophilin C mRNA in a rat middle cerebral artery (MCA) occlusion ischemia model were investigated by Northern blotting and in situ hybridization. Both CyCAP and cyclophilin C mRNAs were ubiquitously distributed in the neurons of the normal brain. Expression increased in neurons of the periinfarct zone up to 7 days after MCA occlusion. The neuronal distribution was confirmed by counterimmunostaining of NeuN. Both mRNAs were predominantly expressed in microglia of the ischemic core at 7 days, confirmed by immunostaining with the microglial marker, ED1. The quantification of CyCAP and cyclophilin C mRNAs at 7 days by Northern blot analysis showed the 8.5-fold increase ( P<0.005, n=6) and 6.8-fold increase ( P<0.005, n=6), respectively, in ischemic core compared with control. The coincidence of CyCAP and cyclophilin C expression in neurons and microglia suggests distinct roles in each cellular population. In particular, the early increase in penumbral neurons might be related to protection in periinfarct neurons.
Observation of a deuteron nuclear magnetic resonance Knight shift in conductive polyaniline
Authors: Goddard Yanina A. , Vold Robert L. , Cross Jennifer , Espe Matthew P. , Hoatson Gina L.
Published: January 2005

Solid state deuteron magic angle spinning nuclear magnetic resonance spectra of conductive ring-deuterated polyaniline consist of two peaks, one at the same chemical shift as the insulating form of the polymer and the second shifted by 5.8±1 ppm. The magnitude of the shift is field and temperature independent and is identified as a Knight shift. The deuterons undergoing a Knight shift originate from both the crystalline and amorphous regions of the sample, implying that conduction is mediated by delocalized polarons in both these regions. Spin count experiments demonstrate that in highly conductive samples, signal is lost not only by dephasing due to the proximity of localized unpaired electrons but also to high rf reflectance.
Does synchronization of networks of chaotic maps lead to control?
Authors: Zhu Mingqiang , Armbruster Dieter , Katzorke Ines
Published: January 2005

We consider networks of chaotic maps with different network topologies. In each case, they are coupled in such a way as to generate synchronized chaotic solutions. By using the methods of control of chaos we are controlling a single map into a predetermined trajectory. We analyze the reaction of the network to such a control. Specifically we show that a line of one-dimensional logistic maps that are unidirectionally coupled can be controlled from the first oscillator whereas a ring of diffusively coupled maps cannot be controlled for more than 5 maps. We show that rings with more elements can be controlled if every third map is controlled. The dependence of unidirectionally coupled maps on noise is studied. The noise level leads to a finite synchronization lengths for which maps can be controlled by a single location. A two-dimensional lattice is also studied.
Real-time monitoring and process control in amorphous∕crystalline silicon heterojunction solar cells by spectroscopic ellipsometry and infrared spectroscopy
Authors: Fujiwara Hiroyuki , Kondo Michio
Published: January 2005

In amorphous∕crystalline silicon heterojunction solar cells, we have performed real-time thickness control of hydrogenated amorphous silicon (a-Si:H) layers with a precision better than ±1Å by applying spectroscopic ellipsometry (SE). A heterojunction solar cell fabricated by this process shows a relatively high conversion efficiency of 14.5%. At the amorphous∕crystalline interface, however, infrared attenuated total reflection spectroscopy (ATR) revealed the formation of a porous a-Si:H layer with a large SiH2-hydrogen content of 27 at. %. Based on SE and ATR results, we discuss the growth processes and structures of a-Si:H in heterojunction solar cells.
Ultrafast optical response of a high-reflectivity GaAs∕AlAs Bragg mirror
Authors: Hastings Sara R. , de Dood Michiel J. A. , Kim Hyochul , Marshall William , Eisenberg Hagai S. , Bouwmeester Dirk
Published: January 2005

The ultrafast response of a high-reflectivity GaAs∕AlAs Bragg mirror to optical pumping is investigated for all-optical switching applications. Both Kerr and free carrier nonlinearities are induced with 100 fs, 780 nm pulses with a fluence of 0.64 and 0.8kJ∕m2. The absolute transmission of the mirror at 931 nm increases by a factor of 27 from 0.0024% to 0.065% on a picosecond time scale. These results demonstrate the potential for a high-reflectivity ultrafast switchable mirror for quantum optics and optical communication applications. A design is proposed for a structure to be pumped below the band gaps of the semiconductor mirror materials. Theoretical calculations on this structure show switching ratios up to 2200 corresponding to switching from 0.017% to 37.4% transmission.
Is Light in Pictures Presumed to Come from the Left Side?
Authors: McManus I Christopher , Buckman Joseph , Woolley Euan
Published: January 2005

For good ecological reasons humans assume that the illumination in pictures comes from overhead rather than from below. Recent work has also raised the possibility that the preferred angle of illumination is between 20° and 30° to the left of vertical, although the ecological basis for that is obscure. We describe two studies of this question. In study 1, twenty subjects looked in free, unrestricted vision, at a picture of a single ‘bubble’ which appeared either convex if the illumination was from above, or concave if the illumination was from below. There was no evidence in study 1 that illumination from the left produced a different appearance from illumination from the right, the preferred angle of illumination being 0.5° to the right of vertical. In study 2, on forty subjects, there was fast presentation (200 ms) of an array of 16 bubbles, one of which, the target, was illuminated from the opposite direction to the others, and hence ‘popped out’ from the display, appearing concave if the others were convex, or vice-versa. The preferred angle of illumination for detection of the target was about 14° to the left of vertical in study 2. The estimates from studies 1 and 2 did not differ significantly, and when combined gave a preferred angle of 9° to the left of vertical. The reasons for the seeming discrepancy between studies 1 and 2, or the smaller overall effect than that found in previous studies are not clear since the methodologies seem equivalent. In both studies 1 and 2 there was a highly significant association between the direction of spontaneous head tilt and preferred direction of illumination, and this factor has not previously been taken into account in studies of the phenomenon. Contrary to the study of Sun and Perona (1998, Nature Neuroscience1 183–184), there was no association with handedness or other measures of functional lateralisation.
Syncytin-A and syncytin-B, two fusogenic placenta-specific murine envelope genes of retroviral origin conserved in Muridae
Authors: Dupressoir Anne , Marceau Geoffroy , Vernochet Cécile , Bénit Laurence , Kanellopoulos Colette , Sapin Vincent , Heidmann Thierry
Published: January 2005

Recently, we and others have identified two human endogenous retroviruses that entered the primate lineage 25–40 million years ago and that encode highly fusogenic retroviral envelope proteins (syncytin-1 and -2), possibly involved in the formation of the placenta syncytiotrophoblast layer generated by trophoblast cell fusion at the materno–fetal interface. A systematic
in silico
search throughout mouse genome databases presently identifies two fully coding envelope genes, present as unique copies and unrelated to any known murine endogenous retrovirus, that we named syncytin-A and -B. Quantitative RT-PCR demonstrates placenta-specific expression for both genes, with increasing transcript levels in this organ from 9.5 to 14.5 days postcoitum.
In situ
hybridization of placenta cryosections further localizes these transcripts in the syncytiotrophoblast-containing labyrinthine zona. Consistently, we show that both genes can trigger cell–cell fusion in
ex vivo
transfection assays, with distinct cell type specificities suggesting different receptor usage. Genes orthologous to syncytin-A and -B and disclosing a striking conservation of their coding status are found in all Muridae tested (mouse, rat, gerbil, vole, and hamster), dating their entry into the rodent lineage ≈20 million years ago. Together, these data strongly argue for a critical role of syncytin-A and -B in murine syncytiotrophoblast formation, thus unraveling a rather unique situation where two pairs of endogenous retroviruses, independently acquired by the primate and rodent lineages, would have been positively selected for a convergent physiological role.
Planar-to-tubular structural transition in boron clusters: B
20
as the embryo of single-walled boron nanotubes
Authors: Kiran Boggavarapu , Bulusu Satya , Zhai Hua-Jin , Yoo Soohaeng , Zeng Xiao Cheng , Wang Lai-Sheng
Published: January 2005

Experimental and computational simulations revealed that boron clusters, which favor planar (2D) structures up to 18 atoms, prefer 3D structures beginning at 20 atoms. Using global optimization methods, we found that the B
20
neutral cluster has a double-ring tubular structure with a diameter of 5.2 Å. For the

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anion, the tubular structure is shown to be isoenergetic to 2D structures, which were observed and confirmed by photoelectron spectroscopy. The 2D-to-3D structural transition observed at B
20
, reminiscent of the ring-to-fullerene transition at C
20
in carbon clusters, suggests it may be considered as the embryo of the thinnest single-walled boron nanotubes.