bluuebunny/crossref_metadata_2025 huggingface dataset:
Hox genes in the antarctic polyplacophoran Nuttallochiton mirandus
Authors: Biscotti Maria Assunta , Canapa Adriana , Olmo Ettore , Barucca Marco
Published: May 2007

Hox genes are conserved across all bilaterians and encode transcription factors involved in the formation of the anteroposterior axis during embryo development. Differences in homeotic gene evolution have been observed not only between deuterostomes and protostomes, but also between the two large protostome clades, Ecdysozoa and Lophotrochozoa.

Among lophotrochozoans, the phylum Mollusca displays high diversity of body plans, ranging from the wormlike appearance of aplacophorans to the complex body plan of cephalopods. Using a PCR‐based method, we were able to identify eight Hox genes in the polyplacophoran Nuttallochiton mirandus, two orthologous to the anterior class (lab, pb), four to the central class (Scr, Lox5, Antp, Lox2) and two to the posterior class (Post‐1, Post‐2). Comparison with the results obtained in other molluscs seems to confirm the conservation of Hox genes in this phylum in terms of both presence and characteristics. J. Exp. Zool. (Mol. Dev. Evol.) 308B:507–513, 2007. © 2007 Wiley‐Liss, Inc.
Detection of cocaine in the airborne particles of the Italian cities Rome and Taranto
Authors: Cecinato Angelo , Balducci Catia
Published: May 2007

Cocaine was first detected in the air of two Italian cities, Rome and Taranto, where it reached concentrations sometimes exceeding 100 pg/m3, by HRGC–MS analysis of carbonaceous aerosol samples. By contrast, the drug was virtually absent in Algiers (Algeria). In Italy, atmospheric concentrations of cocaine were, on average, similar to those of other toxic pollutants like polychlorobiphenyls or nitrated polynuclear aromatic hydrocarbons, and higher than those of polychlorodibenzo‐p‐dioxins/polychlorodibenzofurans. The cocaine concentrations seemed to correlate with regional consumption of the drug in Rome and Taranto. By contrast, it correlated neither with nicotine or caffeine, nor with benzo[a]pyrene, the sole organic compound associated with aerosols that is quoted according to Italian legislation.
Edge-pumped asymmetric Yb:YAG/YAG thin disk laser
Authors: Liu Q , Fu X , Ma D , Yan X , He F , Huang L , Gong M , Wang D
Published: May 2007

An edge-pumping scheme for a quasi-three-level solid-state laser using asymmetric crystal is reported. The scheme uses a thin disk laser configuration with the pump light incident from disk edges. The pump light propagates through the disk along the zigzag path and repeatedly passes the gain medium, thus improving the pump uniformity and absorption efficiency. A maximum output power of over 123 W was achieved from an edge-pumped composite Yb:YAG/YAG thin disk laser, with slope efficiency of 34.8% and beam qualityM2≈ 20.
Mechanical Properties of Comonomer‐Compositionally Fractionated Poly[(3‐hydroxybutyrate)‐co‐(3‐mercaptopropionate)] with Low 3‐Mercaptopropionate Unit Content
Authors: Yu Fang , Dong Tungalag , Zhu Bo , Tajima Kouichirou , Yazawa Kouji , Inoue Yoshio
Published: May 2007

The mechanical properties, such as Young's modulus, yield strength, and the elongation at breakage, were investigated for several sulfur‐containing biopolymers P(3HB‐co‐3MP). A series of P(3HB‐co‐3MP) samples with 3MP unit content ranging from 6.6 to 39.1 mol‐% was biosynthesized by fermentation using the PHA‐synthesizing bacteria Cupriavidus necator. For comparison, the bacterially synthesized P(3HB) and P(3HB‐co‐3HP) with the 3HP unit content ranging from 13.1 to 21.1 mol‐% were also investigated. It was found that the sulfur‐containing P(3HB‐co‐3MP) is much more durable to stretching. Notably, P(3HB‐co‐3MP) with the 3MP unit content of only 6.6 mol‐% was found to show excellent mechanical properties.

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Direct Transfer of Preformed Patterned Bio‐Nanocomposite Films on Polyelectrolyte Multilayer Templates
Authors: Kohli Neeraj , Worden Robert M. , Lee Ilsoon
Published: May 2007

Microarrays containing multiple, nanostructured layers of biological materials would enable high‐throughput screening of drug candidates, investigation of protein‐mediated cell adhesion, and fabrication of novel biosensors. In this paper, we have examined in detail an approach that allows high‐quality microarrays of layered, bionanocomposite films to be deposited on virtually any substrate. The approach uses LBL self‐assembly to pre‐establish a multilayered structure on an elastomeric stamp, and then uses µCP to transfer the 3‐D structure intact to the target surface. For examples, different 3‐D patterns containing dendrimers, polyelectrolyte multilayers and two proteins, sADH and sDH, have been fabricated. For the first time, the approach was also extended to create overlaid bionanocomposite patterns and multiple proteins containing patterns. The approach overcomes a problem encountered when using µCP to establish a pattern on the target surface and then building sequential layers on the pattern via LBL self‐assembly. Amphiphilic molecules such as proteins and dendrimers tend to adsorb both to the patterned features as well as the underlying substrate, resulting in low‐quality patterns. By circumventing this problem, this research significantly extends the range of surfaces and layering constituents that can be used to fabricate 3‐D, patterned, bionanocomposite structures.

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Variation in Copolymer Composition and Molecular Weight of Polyhydroxyalkanoate Generated by Saturation Mutagenesis of Aeromonas caviae PHA Synthase
Authors: Tsuge Takeharu , Watanabe Shinko , Sato Shun , Hiraishi Tomohiro , Abe Hideki , Doi Yoshiharu , Taguchi Seiichi
Published: May 2007

Amino acid substitutions at two residues downstream from the active‐site histidine of polyhydroxyalkanoate (PHA) synthases are effective for changing the composition and the molecular weight of PHA. In this study, saturation mutagenesis at the position Ala505 was applied to PHA synthase (PhaCAc) from Aeromonas caviae to investigate the effects on the composition and the molecular weight of PHA synthesized in Ralstonia eutropha. The copolymer composition and molecular weight of PHA were varied by association with amino acid substitutions. There was a strong relationship between copolymer composition and PHA synthase activity of the cells. This finding will serve as a rationale for producing tailor‐made PHAs.

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Enhanced Stereocomplex Formation of Poly(L‐lactic acid) and Poly(D‐lactic acid) in the Presence of Stereoblock Poly(lactic acid)
Authors: Fukushima Kazuki , Chang Yoon‐Hee , Kimura Yoshiharu
Published: May 2007

Stereoblock poly(lactic acid) (sb‐PLA) is incorporated into a 1:1 polymer blend system of poly(L‐lactic acid) (PLLA) and poly(D‐lactic acid) (PDLA) that has a high molecular weight to study its addition effect on the stereocomplex (sc) formation of PLLA and PDLA. The ternary polymer blend films are first prepared by casting polymer solutions of sb‐PLA, PLLA, and PDLA with different compositions. Upon increasing the content of sb‐PLA in the blend films the sc crystallization is driven to a higher degree, while the formation of homo‐chiral (hc) crystals is decreased. Lowering the molecular weight of the incorporated sb‐PLA effectively increases the sc formation. Consequently, it is revealed that sb‐PLA can work as a compatibilizer to improve the poor sc formation in the polymer blend of PLLA and PDLA.

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The Nonexistence of a Binary Homogeneous Pseudoplane
Authors: Thomas Simon
Published: May 2007

We prove that there are no binary homogeneous pseudoplanes.
A Fine Structure in the Theory of Isols
Authors: Barback Joseph
Published: May 2007

In this paper we introduce a collection of isols having some interesting properties. Imagine a collection W of regressive isols with the following features: (1) u, v ϵ W implies that u ⩽ v or v ⩽ u, (2) u ⩽ v and v ϵ W imply u ϵ W, (3) W contains ℕ = {0,1,2,…} and some infinite isols, and (4) u eϵ W, u infinite, and u + v regressive imply u + v ϵ W. That such a collection W exists is proved in our paper. It has many nice features. It also satisfies (5) u, v ϵ W, u ⩽ v and u infinite imply v ⩽ g(u) for some recursive combinatorial function g, and (6) each u ϵ W is hereditarily odd‐even and is hereditarily recursively strongly torre. The collection W that we obtain may be characterized in terms of a semiring of isols D(c) introduced by J. C. E. Dekker in [5]. We will show that W = D(c), where c is an infinite regressive isol that is called completely torre.
Sur la détermination d'une relation binaire à partir d'informations locales
Authors: Boudabbous Youssef
Published: May 2007

This paper deals with the problematic aspect of the reconstruction of binary relations: it includes all the questions raising the possibility or impossibility to determine a structure by gathering given substructures. It is the continuation of three studies: the first made by G. Lopez [9] in 1972 about the determination of a binary relation through the types of isomorphism of its restrictions, the second made by K. B. Reid and C. Thomassen [15] in 1976 about the strongly self‐complementary tournaments (every subtournament is self‐complementary), the third made by C. Thomassen [16] in 1989 about the cycle space of a tournament. In the second section, we use the notion of class of difference (which was introduced in [9]) to extend a study made in [16] to binary relations. Then, in the third section, we improve the result of this last study in the case of the tournaments. After noticing that the result of [15] inferred itself naturally from the approach developed in [9], we extend, in the fourth section, the study made in [15] to binary relations.
Versions of Normality and Some Weak Forms of the Axiom of Choice
Authors: Howard Paul , Keremedis Kyriakos , Rubin Herman , Rubin Jean E.
Published: May 2007

We investigate the set theoretical strength of some properties of normality, including Urysohn's Lemma, Tietze‐Urysohn Extension Theorem, normality of disjoint unions of normal spaces, and normality of Fσ subsets of normal spaces.
On a Theory for AC0and the Strength of the Induction Scheme
Authors: Kuroda Satoru
Published: May 2007

We define a fragment of Primitive Recursive Arithmetic by replacing the defining axioms for primitive recursive functions by those for functions in some specific complexity class. In this note we consider such theory for AC0. We present a model‐theoretical property of this theory, by means of which we are able to characterize its provably total functions. Next we consider the problem of how strong the induction scheme can be in this theory.
Interpolation by a Game
Authors: Kraíček Jan
Published: May 2007

We introduce a notion of a real game (a generalisation of the Karchmer‐Wigderson game (cf. [3]) and of real communication complexity, and relate this complexity to the size of monotone real formulas and circuits. We give an exponential lower bound for tree‐like monotone protocols (defined in [4, Definition 2.2]) of small real communication complexity solving the monotone communication complexity problem associated with the bipartite perfect matching problem. This work is motivated by a research in interpolation theorems for prepositional logic (by a problem posed in [5, Section 8], in particular). Our main objective is to extend the communication complexity approach of [4, 5] to a wider class of proof systems. In this direction we obtain an effective interpolation in a form of a protocol of small real communication complexity. Together with the above mentioned lower bound for tree‐like protocols this yields as a corollary a lower bound on the number of steps for particular semantic derivations of Hall's theorem (these include tree‐like cutting planes proofs for which an exponential lower bound was demonstrated in [2]).
Difference Sets and Recursion Theory
Authors: Schmerl James H.
Published: May 2007

There is a recursive set of natural numbers which is the difference set of some recursively enumerable set but which is not the difference set of any recursive set.
The Analytic Polynomial‐Time Hierarchy
Authors: Baier Herbert , Wagner Klaus W.
Published: May 2007

Motivated by results on interactive proof systems we investigate an ∃‐∀hierarchy over P using word quantifiers as well as two types of set quantifiers. This hierarchy, which extends the (arithmetic) polynomial‐time hierarchy, is called the analytic polynomial‐time hierarchy. It is shown that every class of this hierarchy coincides with one of the following Classes: ∑, Π(k⩾0), PSPACE, ∑or Π(k⩾1). This improves previous results by Orponen [6] and allows interesting comparisons with the above mentioned results on inter‐active proof systems.
Free Algebras in Certain Varieties of Distributive Pseudocomplemented De Morgan Algebras
Authors: Gaitán Hernando
Published: May 2007

In this paper we characterize the join irreducible elements of the free algebras onnfree generators in the subvarieties of the varietyV0of pseudocomplemented De Morgan algebras satisfying the identityxx′* = (xx′*)′*.
Clinical diagnostic criteria for dementia associated with Parkinson's disease
Authors: Emre Murat , Aarsland Dag , Brown Richard , Burn David J. , Duyckaerts Charles , Mizuno Yoshikino , Broe Gerald Anthony , Cummings Jeffrey , Dickson Dennis W. , Gauthier Serge , Goldman Jennifer , Goetz Christopher , Korczyn Amos , Lees Andrew , Levy Richard , Litvan Irene , McKeith Ian , Olanow Warren , Poewe Werner , Quinn Niall , Sampaio Christina , Tolosa Eduardo , Dubois Bruno
Published: May 2007

Dementia has been increasingly more recognized to be a common feature in patients with Parkinson's disease (PD), especially in old age. Specific criteria for the clinical diagnosis of dementia associated with PD (PD‐D), however, have been lacking. A Task Force, organized by the Movement Disorder Study, was charged with the development of clinical diagnostic criteria for PD‐D. The Task Force members were assigned to sub‐committees and performed a systematic review of the literature, based on pre‐defined selection criteria, in order to identify the epidemiological, clinical, auxillary, and pathological features of PD‐D. Clinical diagnostic criteria were then developed based on these findings and group consensus. The incidence of dementia in PD is increased up to six times, point‐prevelance is close to 30%, older age and akinetic‐rigid form are associated with higher risk. PD‐D is characterized by impairment in attention, memory, executive and visuo‐spatial functions, behavioral symptoms such as affective changes, hallucinations, and apathy are frequent. There are no specific ancillary investigations for the diagnosis; the main pathological correlate is Lewy body‐type degeneration in cerebral cortex and limbic structures. Based on the characteristic features associated with this condition, clinical diagnostic criteria for probable and possible PD‐D are proposed. © 2007 Movement Disorder Society
Group invariant solution for axisymmetric spreading of a thin fluid film with slip at the fluid–base interface
Authors: Mason D. P. , Chung M. Y.
Published: May 2007

The axisymmetric spreading of a thin fluid film with slip at the horizontal base is investigated. A nonlinear diffusion equation is derived which relates the height of the free surface to the slip velocity. The equation possesses a Lie point symmetry provided the slip velocity satisfies a first‐order quasi‐linear partial differential equation. Group invariant solutions are derived with no singularities at the moving contact line. Vortices can exist close to the axis or at the base. The thin film spreads by slipping at the base or by a rolling motion in the vicinity of the moving contact line. Copyright © 2007 John Wiley & Sons, Ltd.
Proportional representation: A trial resuscitation of a comatose patient
Authors: Petrie Bruce I. , Tuchfarber Alfred J.
Published: May 2007

Last November, after a hiatus of more than 30 years, approximately 1,000 Cincinnati voters were invited to select candidates for city council using the Hare System of Proportional Representation (PR) In a unique exit‐poll experiment. The result: re‐adoption of PR in Cincinnati would necessitate changes in 1) how campaigns are conducted. 2) the size of party tickets, and 3) who gets elected. It might also affect how the city is governed.
Metropolitan governance: Citizen participation in the Urban federation
Authors: Henderson Lenneal J.
Published: May 2007

In spite of their technical and professional reputations, regional councils of governments are both attracting and actively soliciting citizen input. The research presented in this article suggests that increasing diversity of representation in COGs has paralleled the empowerment in local governments of traditionally underrepresented populations. More importantly, COGs are making the transition from primary reliance on elected officials for policy formulation to more direct citizen involvement.
Hillsborough county: A comprehensive approach to productivity improvement
Authors: Bramson Ruth , Mayer Dick
Published: May 2007

In Hillsborough County, Florida, the installment of a productivity‐improvement program meant wholesale abandonment of “business as usual.” The four imperatives of the Hillsborough approach: 1) convey a clear sense of why change is necessary; 2) provide enabling resources; 3) create an organizational structure in which innovative individuals and teams can flourish; and 4) rearrange incentives to reward performance.
Local government reform: Its nature, impact, and relevance to regionalism
Authors: Svara James H.
Published: May 2007

A primary goal of the progressive reform movement was and continues to be an expansion of leadership that will address the true needs of communities. In fact, reform institutions have had this impact. The practices long advocated for cities and counties are strikingly relevant to our urban regions as well: A “regional governance council.” adapted from the council‐manager form of government, should be considered for regions and metro areas.
Youth as resources in the fight against drugs
Authors: Calhoun John A.
Published: May 2007

Society tends to overlook youth until they cross a pathological line — get into trouble. The “youth as resources” approach encourages those interested in working with youth to “claim” and harness the energy of young people in carrying out valuable community projects. The three year‐old Youth as Resources Against Drugs pilot project has had measured positive effects on youth and agencies working with youth.
Reforming public practices and improving quality of life: The public speaks
Authors: Johnson Kathryn E. , Hochstein Madelyn , Grossman Wynne , Griffin Ellen
Published: May 2007

Public attitudes toward sound health and the surest means of achieving and sustaining it offer instructive insights into their perceptions of other, broad social and community challenges. Americans will incur significant sacrifices to enhance their quality of life and personal and family security, provided the burdens are shared fairly and public leaders dispense benefits and enforce obligations equitably.
The third wave: Current trends in regional governance
Authors: Wallis Allan D.
Published: May 2007

The past emphasis on structural regionalism, rendered infeasible by political considerations, has given way to a third wave, characterized by cross‐sectoral alliances. Sustained by rich networks of affiliations among public, private and nonprofit sector organizations, this new approach to regionalism is being acknowledged and nurtured by several state and federal initatives.
Possible spectroscopic manifestation of the angular group induced bond alteration (AGIBA) effect in toluene
Authors: Kirillov S. A. , Morresi A. , Paolantoni M. , Sassi P.
Published: May 2007

The most obvious consequence of the concept of aromaticity is the common confidence that in aromatic compounds, bond lengths do not alternate and are between typical to the single and double ones. However, in 1994, performing crystal structure investigations of substituted pyridines and their salts, Krygowski and co‐workers have discovered a very surprising angular group induced bond alteration (AGIBA) effect: It appears that some angular substituents, like methoxy or nitrozo groups, can induce bond alternation in aromatic rings. Crystal studies do not allow one to operate with liquids that are more common in organic chemistry. This paper presents the first possible evidence of spectroscopic manifestations of the AGIBA effect. Raman spectra of the liquid toluene are analyzed. It is found that instead of being single, the line corresponding to the ring breathing vibrations is clearly split by 1.0–1.4 cm−1, thus indicating the presence of two (cis‐ and trans‐) AGIBA isomers. The energy difference between these isomers estimated in temperature dependent Raman studies is found equal to 6.68 kJ mol−1. The low‐wavenumber line therefore corresponds to the cis‐AGIBA isomer and the high‐wavenumber line to the trans‐AGIBA isomer stabilized by the AGIBA effect. Copyright © 2007 John Wiley & Sons, Ltd.
High power violet laser diodes with crack‐free layers on GaN substrates
Authors: Ito Shigetoshi , Kamikawa Takeshi , Ueta Yoshihiro , Takatani Kunihiro , Yamasaki Yukio , Yuasa Takayuki , Taneya Mototaka
Published: May 2007

Nitride based violet laser diodes grown on GaN substrates have been investigated. A grooved substrate, having a striped pattern with a pitch of 400 μm, has been prepared and epitaxial growth has been performed. No cracks have been observed in the epi‐layers. The violet laser device has been fabricated and characterised. At a pulsed output power of 210 mW, the operating current and the voltage have been 164 mA and 6.6 V, respectively. The mean‐time‐to‐failure has been estimated to be over 3000 h under pulsed condition with an output power of 210 mW at 80 °C. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Formation of atomic‐sized contacts controlled by electrochemical methods
Authors: Reyes Calvo M. , Mares Ancuta I. , Climent Victor , van Ruitenbeek Jan M. , Untiedt Carlos
Published: May 2007

Electrochemical methods have recently become an interesting tool for fabricating and characterizing nanostructures at room temperature. Simplicity, low cost and reversibility are some of the advantages of this technique that allows to work at the nanoscale without requiring sophisticated instrumentation. In our experimental setup, we measure the conductance across a nanocontact fabricated either by dissolving a macroscopic gold wire or by depositing gold in between two separated gold electrodes. We have achieved a high level of control on the electrochemical fabrication of atomic‐sized contacts in gold. The use of electrochemistry as a reproducible technique to prepare nanocontacts will open several possibilities that are not feasible with other methodologies. It involves, also, the possibility of reproducing experiments that today are made by more expensive, complicated or irreversible methods. As example, we show here a comparison of the results when looking for shell effects in gold nanocontacts with those obtained by other techniques. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Formation of atomic‐sized contacts controlled by electrochemical methods
Authors: Reyes Calvo M. , Mares Ancuta I. , Climent Victor , van Ruitenbeek Jan M. , Untiedt Carlos
Published: May 2007

The present special issue of physica status solidi (a) contains contributions from the TNT2006 – Trends in Nanotechnology Conference, held in Grenoble, France, 4–8 September 2006.

Editor's Choice is the article by Reyes Calvo et al. [1], which reports on the possibilities of using electrochemical methods to form atomic‐sized contacts. In particular, the authors analyze previous attempts and propose improvements on several methods, in order to increase the control and the ease of preparation of the nanocontacts. The cover picture shows the electrochemical cell (1 cm in diameter) used for the experiments (left) with a schematic of the electronic circuit used. An artistic view of the atomic contact is depicted at the top. The lower right panel shows the last stages of the evolution of the conductance of a gold wire while being electrochemically etched. The last plateau of conductance corresponds to a one‐atom contact. The upper right panel shows the voltamogram of the wire prior to etching.

This work was done mainly at the Low Temperatures & Nanotechnology Laboratory of the University of Alicante (Spain), lead by Dr. Carlos Untiedt. He is a “Ramon y Cajal” Researcher whose main research interest is the electronic transport in nanostructures, and in particular in atomic‐sized contacts.

The issue also contains an Original Paper on scientific policy entitled “Nanotechnology applications: a driving force for R&D investment” [2], and a Feature Article presenting a report on the synthesis of luminescent silicon nanostructures by means of laser ablation techniques by Riabinia et al. [3]. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Stable husbands
Authors: Knuth Donald E. , Motwani Rajeev , Pittel Boris
Published: May 2007

Suppose n boys and n girls rank each other at random. We show that any particular girl has at least (1/2 − ϵ) in n and at most (1 + ϵ) in n different husbands in the set of all Gale/Shapley stable matchings defined by these rankings, with probability approaching 1 as n → ∞, if ϵ is any positive constant. the proof emphasizes general methods that appear to be useful for the analysis of many other combinatorial algorithms.
On tree census and the giant component in sparse random graphs
Authors: Pittel Boris
Published: May 2007

For each of the two models of a sparse random graph on n vertices, G(n, # of edges = cn/2) and G(n, Prob (edge) = c/n) define tn(k) as the total number of tree components of size k (1 ≤ k ≤ n). the random sequence {[tn(k) ‐ nh(k)]n−1/2} is shown to be Gaussian in the limit n →∞, with h(k) = kk−2ck−1e−kc/k! and covariance function being dependent upon the model. This general result implies, in particular, that, for c> 1, the size of the giant component is asymptotically Gaussian, with mean nθ(c) and variance n(1 − T)−2(1 − 2Tθ)θ(1 − θ) for the first model and n(1 − T)−2θ(1 − θ) for the second model. Here Te−T = ce−c, T<1, and θ = 1 − T/c. A close technique allows us to prove that, for c < 1, the independence number of G(n, p = c/n) is asymptotically Gaussian with mean nc−1(β + β2/2) and variance n[c−1(β + β2/2) −c−2(c + 1)β2], where βeβ = c. It is also proven that almost surely the giant component consists of a giant two‐connected core of size about n(1 − T)β and a “mantle” of trees, and possibly few small unicyclic graphs, each sprouting from its own vertex of the core.
An application of Lovász' local lemma‐A new lower bound for the van der Waerden number
Authors: Szabó Zoltán
Published: May 2007

The van der Waerden number W(n) is the smallest integer so that if we divide the integers {1,2, …, W(n)} into two classes, then at least one of them contains an arithmetic progression of length n. We prove in this paper that W(n) ≥ 2n/nϵ for all sufficiently large n.
A random tree model associated with random graphs
Authors: Aldous David
Published: May 2007

Grow a tree on n vertices by starting with no edges and successively adding an edge chosen uniformly from the set of possible edges whose addition would not create a cycle. This process is closely related to the classical random graph process. We describe the asymptotic structure of the tree, as seen locally from a given vertex. In particular, we give an explicit expression for the asymptotic degree distribution. Our results an be applied to study the random minimum‐weight spanning tree question, when the edge‐weight distribution is allowed to vary almost arbitrarily with n.
On the expected performance of a parallel algorithm for finding maximal independent subsets of a random graph
Authors: Calkin Neil J. , Frieze A. M. , Kučera L.
Published: May 2007

We consider the parallel greedy algorithm of Coppersmith, Raghavan, and Tompa (Proc. of 28th Annual IEEE Symp. on Foundations of Computer Science, pp. 260–269, 1987) for finding the lexicographically first maximal independent set of a graph. We prove an Ω(log n) bound on the expected number of iterations for most edge densities. This complements the O(log n) bound proved in Calkin and Frieze (Random Structures and Algorithms, Vol. 1, pp. 39–50, 1990).
An example of a superproportional graph
Authors: Kärrman Jan
Published: May 2007

In the theory of random graphs, several classes of graphs occur that are exceptional cases in limit theorems for subgraph counts. The purpose of this article is to show the existence of graphs in one of these classes, by providing an explicit, computer generated, example. We also show that the class is closed under complementation. © 1994 John Wiley & Sons, Inc.
On the number of subtrees for almost all graphs
Authors: Tomescu Ioan
Published: May 2007

In this article it is shown that the number of common edges of two random subtrees of Kn having r and s vertices, respectively, has a Poisson distribution with expectation 2λμ if \documentclass{article}\pagestyle{empty}\begin{document}$\mathop {\lim }\limits_{n \to \infty } r/n = \lambda$\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$\mathop {\lim }\limits_{n \to \infty } s/n = \mu$\end{document}. Also, some estimations of the number of subtrees for almost all graphs are made by using Chebycheff's inequality. © 1994 John Wiley & Sons, Inc.
Infinitary queries and their asymptotic probabilities. II. Properties definable in least fixed point logic
Authors: Tyszkiewicz Jerzy
Published: May 2007

We develop an almost complete theory for existence of asymptotic probabilities of least fixed point and partial fixed pint definable properties, and for the complexity of the associated almost sure theory. Our method works for any randomized class of finite structures. © 1994 John Wiley & Sons, Inc.
Adaptive power control for satellite to ground laser communication
Authors: Gubergrits Michael , Goot Roman E. , Mahlab Uri , Arnon Shlomi
Published: May 2007

We develop an adaptive power control algorithm to facilitate satellite to ground laser communication through turbulence fading channels. Adaptive control is a powerful tool that improves energetic gain of the satellite laser. We use discrete laser transmitter intensity levels in our control algorithm. A novel recursive technique defines optimal laser transmitting intensity levels so that the laser‐transmitted power is adapted according to instant changes of the signal‐to‐noise ratio caused by channel fading. The algorithm's performance is first investigated in a general form suitable for any channel fading statistics. Then it is specified for a typical lognormal fading channel. The results indicate an improvement of up to 10dB in energetic gain. Copyright © 2007 John Wiley & Sons, Ltd.
Sustainable development in Rwanda: industry and government
Authors: Short Tim
Published: May 2007

This paper discusses the results of research carried out in Rwanda, in February 2005, through funding from the Royal Society. It investigates the methodologies and policies in use in Rwanda to promote and ensure sustainable industrial development and examines the Government's role in providing an appropriate framework. The paper considers the situation in Rwanda, following the 1994 genocide, and the part played by the Kigali Institute of Science, Technology and Management (KIST), formed with the specific remit of training a new generation of professionals to replace those lost in 1994. Finally it recognises similarities between manufacturing in the UK and in Rwanda, demonstrating how far Rwanda has come since the genocide. Copyright © 2007 John Wiley & Sons, Ltd and ERP Environment.
Parametric latent class joint model for a longitudinal biomarker and recurrent events
Authors: Han Jun , Slate Elizabeth H. , Peña Edsel A.
Published: May 2007

A joint model for a longitudinal biomarker and recurrent events is proposed. This general model accommodates the effects of covariates on the biomarker and event processes, the effects of accumulating event occurrences, and effects caused by interventions after each event occurrence. Association between the biomarker and recurrent event processes is captured through a latent class structure, which also serves to handle an underlying heterogeneous population. We use the EM algorithm for maximum likelihood estimation of the model parameters and a penalized likelihood measure to determine the number of latent classes. This joint model is validated by simulation and illustrated with a data set from epileptic seizure study. Copyright © 2007 John Wiley & Sons, Ltd.
A model‐driven approach to automatic conversion of physical units
Authors: Cooper Jonathan , McKeever Steve
Published: May 2007

When physical quantities are used in programs they are typically represented as raw numbers, with the units in which they were measured only being given in comments, if at all. This can lead to errors from the use of dimensionally inconsistent expressions, or the comparison of two quantities of the same dimension but measured in different units, which are not discovered until run time. Any program working with the physical world has this issue, with scientific modelling being a major application. Implementors of models have the time‐consuming and error‐prone task of adding in dynamic units checks and conversions manually. Most existing programming languages do not provide support for representing units explicitly (although extensions to some have been proposed). With the advent of domain‐specific modelling languages, incorporating code generation techniques, we propose checking physical units at the level of the modelling language, removing the need for such a support in the underlying implementation language. We present our work in the context of one such modelling language: CellML, developed at the
University of Auckland with a focus on modelling biological systems. We have developed an intuitive algorithm for performing automatic conversions between quantities measured in different units. It both requires fewer conversion operations than current approaches and makes more sensible choices about which quantities to convert. Uniquely, by using partial evaluation techniques it is also capable of dealing robustly with quantities raised to arbitrary powers, even where the exponent is given by an expression. We demonstrate our algorithm on various examples. Copyright © 2007 John Wiley & Sons, Ltd.
A comparison study of 12 paradigms for developing embodied agents
Authors: Bölöni Ladislau , Luotsinen Linus J. , Ekblad Joakim N. , Fitz‐Gibbon T. Ryan , Houchin Charles , Key Justin L. , Khan Majid Ali , Lyu Jin , Nguyen Johann , Oleson Rex , Stein Gary , Vander Weide Scott A. , Trinh Viet
Published: May 2007

We report on a study in which 12 different paradigms were used to implement agents acting in an environment which borrows elements from artificial life and multi‐player strategy games. In choosing the paradigms we strived to maintain a balance between high‐level, logic‐based approaches and low‐level, physics‐oriented models; between imperative programming, declarative approaches and ‘learning from basics’; between anthropomorphic or biologically inspired models on one hand and pragmatic, performance‐oriented approaches on the other. We have found that the choice of the paradigm determines the software development process and requires a different set of skills from the developers. In terms of raw performance, we found that the best performing paradigms were those which (a) allowed the knowledge of human experts to be explicitly transferred to the agent and (b) allowed the integration of well‐known, high‐performance algorithms. We have found that maintaining a commitment to the chosen paradigm can be difficult; there is a strong temptation to offer shallow fixes to perceived performance problems through a ‘flight into heuristics’. Our experience is that a development process without the discipline enforced by a central paradigm leads to agents which are a random collection of heuristics whose interactions are not clearly understood. Although far from providing a definitive verdict on the benefits of the different paradigms, our study provided a good insight into what kind of conceptual, technical or organizational problems would a development team face depending on their choice of agent paradigm. Copyright © 2007 John Wiley & Sons, Ltd.
Graphische Lösung der Hauptaufgabe der Luftphotogrammetrie im Sinne der Ausgleichsrechnung
Authors: Krames Josef
Published: May 2007

Für die Wiederherstellung der gegenseitigen Lage zweier aus verschiedenen Luftstandpunkten aufgenommenen Geländebilder wird ein einfaches graphisches Verfahren abgeleitet. Dieses gründet sich auf die geometrische Theorie jener „gefährlichen”︁ Geländeflächen, für welche diese Aufgabe in der Praxis nur ungenau bestimmt ist.
Die Ausnutzung zusätzlicher Vorkenntnisse für die Einschließung von Eigenwerten beim Iterationsverfahren
Authors: Kreyszig E.
Published: May 2007

Im Anschluß an eine frühere Arbeit [6]1) wird gezeigt, wie man mit Hilfe einer Theorie von Wielandt [1], [2] spezielle Vorkenntnisse, z. B. über eigenwertfreie Intervalle, etwa im Falle positiver Definitheit, über Schranken für gewisse Eigenwerte usw., für die Einschließung der Eigenwerte einer gegebenen hermiteschen Matrix A bei gegebener Iterationsfolge von Vektoren x0, x1 = A x0…, xs = Asx0 auswerten und dadurch die Einschließung verschärfen kann.
Beiträge zum Runge‐Kutta‐Verfahren
Authors: Albrecht Julius
Published: May 2007

Nach Diskussion eines allgemeinen Runge‐Kutta‐Ansatzes für y(n) = f (x, y, y', …, y(n—1)) werden für die spezielle Differentialgleichung y' = f(x, y) und die durch „Vordifferentiation”︁ in eine solche überführte Differentialgleichung y′ = g(x, y) neue Runge‐Kutta‐Vorschriften hergeleitet. Ferner werden „symmetrische”︁ Runge‐Kutta‐Formeln sowie Fehlerabschätzungen zu den Verfahren von Heun und Kutta für Differentialgleichungen 1. Ordnung angegeben.
Über die Randquerkräfte bei gestützten Platten
Authors: Kromm Alexander
Published: May 2007

Am Beispiel einer allseitig momentenfrei gelagerten Platte mit gleichmäßig verteilter Belastung wird die Anwendung der verallgemeinerten Plattentheorie des Verfassers illustriert, die die Querschubverzerrungen der Platte berücksichtigt. Insbesondere wird die Verteilung der Randquerkräfte und die Frage der Eckkräfte untersucht, die die Rechnung nach der elementaren Plattentheorie liefert.
On the Role of Congestion in Transportation Problems
Authors: Prager William
Published: May 2007

In discussing the most efficient manner of distributing a product from several sources to numerous locations, Hitchcock [1] assumed that the specific transportation cost for a given shipping route was independent of the amount shipped over this route. In the present paper the problem is discussed under the assumption that the specific shipping cost for a route increases linearly with the amount shipped over this route. It is shown that the optimal shipping program then is unique and that it can be discussed either in terms of flows along the routes or in terms of accounting princes at the centers of production and consumption. A maximum principle is established for the accounting prices, which leads to a maximum characterization of the cost of the optimal program.
Berechnung einzelner Eigenwerte eines algebraischen linearen Eigenwertproblems durch „Störiteration”︁
Authors: Wittmeyer H.
Published: May 2007

Eine gegebene Näherungslösung λ(0), x(0) für einen gesuchten beliebigen einfachen Eigenwert λe und den zugehörigen Eigenvektor xe wird durch eine Störungsrechnung erster Ordnung verbessert. Dies Verfahren liefert, zu einer Iteration, der „Störiteration”︁, ausgebaut, die gleiche Folge von Näherungswerten wie die „gebrochene Iteration”︁ von Wielandt. Die Störiteration vermeidet jedoch die Auflösung von linearen Gleichungssystemen mit fast singulären Matrizen. Sie ist besonders geeignet zur Berechnung der Abhängigkeit einer Lösung λe, xe von einem in den Matrizen des Problemes enthaltenen Parameter.
Beitrag zu Walls Verfahren der getrennten Berechnung von Real‐ und Imaginärteilen der Nullstellen eines Polynoms
Authors: Occhini Luiz
Published: May 2007

Bei einem von Wall angegebenen Verfahren zur getrennten Bestimmung der Realteile und Imaginärteile der Nullstellen eines vorgegebenen Polynoms ist man zur Interpolation unglücklicherweise auf Werte einer gebrochen‐rationalen Funktion angewiesen. Ausgehend von dem Ansatz des “Halbsummenpolynoms”, der von Orlando zur Herleitung des Hurwitzschen Stabilitätskriteriums benützt wurde, gelangt man zwanglos zu einer dem Wallschen Vorgehen verwandten und dessen Vorzüge aufrechterhaltenden Methode, die jedoch nunmehr die Interpolation mittels der Werte eines Polynoms ‐ des Halbsummenpolynoms ‐ vorzunehmen gestattet.

Die Vorzüge des Verfahrens kommen besonders bei Benützung programmgesteuerter Rechenanlagen zur Geltung.
Behandlung der Plattenaufgabe nach dem verbesserten Differenzenverfahren
Authors: Zurmühl Rudolf
Published: May 2007

Für die Plattenaufgabe ΔΔu = p/K mit rechteckigen Rändern werden Differenzenformeln höherer Genauigkeit nach dem Mehrstellenverfahren entwickelt, die sowohl das Einarbeiten der Randbedingungen als auch die Berechnung der zweiten Ableitungen, also der Biegemomente mit hoher Genauigkeit ermöglichen. Die Verwendung der Formeln wird für die verschiedenen Lagerungsfälle angegeben und an einigen Zahlenbeispielen erläutert. Ein Vergleich mit bekannten strengen Lösungen zeigt die Güte des Verfahrens.
Beiträge zum Quellsenkenverfahren für die Berechnung von Überschallströmungen
Authors: Münch Johann
Published: May 2007

In der vorliegenden Arbeit werden die Quellsenkenverfahren eingehend untersucht und dahingehend verallgemeinert, daß sie auch auf Drehkörper mit Unstetigkeiten in den Ableitungen der Konturkurve anwendbar sind.
On the Pure Twist of a Thin Plate Containing an Infinite Row of Circular Holes
Authors: Yamashida T.
Published: May 2007

The problem of estimating the influence of an infinite series of equidistant circular holes of equal radius on the distribution of stress in an infinite plate under uniform twisting is treated according to the Poisson‐Kirchhoff theory of thin plates. The parametric coefficients included in the solution of this problem are determined by using the method of perturbation. For some special cases, numerical results are given.
Iterationen von beliebiger Ordnung
Authors: Berg Lothar
Published: May 2007

Es wird ein Verfahren zur direkten Berechnung der Iterierten einer gegebenen Funktion von beliebiger reeller Ordnung angegeben, ohne den Umweg über die Abelsche Gleichung zu gehen. Das Verfahren liefert ein eindeutiges Ergebnis, das sich durch besondere Eigenschaften auszeichnet. Am Beispiel der Iterierten der Funktion ex−1 von der Ordnung 1/2 wird die Konvergenz des Verfahrens numerisch untersucht. Es zeigt sich, daß man die Ausgangsnäherung so wählen kann, daß mit verhältnismäßig wenig Rechenarbeit eine gewünschte Genauigkeit erzielt wird.
Geometrische Untersuchungen über Nomogramme für elliptische Integrale erster Gattung und Jacobische elliptische Funktionen I
Authors: Reutter F.
Published: May 2007

Die vor kurzem in dieser Zeitschrift entwickelte Theorie der nomographischen Darstellbarkeit von Funktionensystemen [1]wird auf Funktionen eines komplexen Arguments angewandt. Insbesondere werden Nomogramme zur Ermittlung der Funktionswerte elliptischer Funktionen und Integrale entwickelt. Ihre geometrische Struktur und ihre zweckmäßige Formgebung werden eingehend untersucht.
Neue genauere Runge‐Kutta‐Formeln für Differentialgleichungen n‐ter Ordnung
Authors: Fehlberg Erwin
Published: May 2007

Durch m‐malige Differentiation und Transformation der Differentalgleichung n‐ter Ordnung können Runge‐Kutta‐Formeln für die transformierte Differentialgleichung angegeben werden, die sowohl für die Lösungsfunktion als auch für deren Ableitungen noch die Glieder mit hm+5 der Taylor‐Reihe genau erfassen.

Diese neuen und genaueren Runge‐Kutta‐Formeln erlauben eine Reduktion der Rechenzeit (auf einer elektronischen Rechenmaschine), da man die Integrationsschrittweite wesentlich vergrößern kann. Einige Beispiele werden gebracht, in denen die gleiche Genauigkeit wie beim üblichen Runge‐Kutta‐Verfahren mit unseren Formeln in 10% und weniger der Runge‐Kutta‐Rechenzeit erzielt wird (für m = 2, 3, 4).
Successive Approximations Process in Analog Solution of Partial Differential Equations by Difference Method
Authors: Matyáš Josef
Published: May 2007

In this paper a method of successive approximations in analog solution of partial differential equations is described. The convergence theorem for a wide class of boundary (or initial‐boundary) value problems is proved. A solution procedure is proposed to reach higher speed of the convergence of the successive approximations process and for estimating the accuracy of the solution. Analog computer solution is briefly discussed.
Violation of Local Realism for Ququats
Authors: Traina Paolo
Published: May 2007

Conclusive experimental tests of local realism deserve a minimum quantum efficiency in order to close detection loophole. This efficiency depends on the considered observables, on the specific Bell inequality chosen and on the dimension of the quantum objects observed. In this paper, we numerically analyse some quantum mechanics predictions on local realism for qubits, qutrits and ququats and we suggest a system to produce ququats maximally violating Bell-CGLMP inequality.
The Role of Surface Plasmon Modes in the Casimir Effect
Authors: Intravaia F. , Lambrecht A.
Published: May 2007

In this paper, we study the role of surface plasmon modes in the Casimir effect. First we write the Casimir energy as the sum over the modes of a real cavity. We may identify two sorts of modes, two evanescent surface plasmon modes and propagative modes. As one of the surface plasmon modes becomes propagative for some choice of parameters we adopt an adiabatic mode definition where we follow this mode into the propagative sector and count it together with the surface plasmon contribution, calling this contribution “plasmonic”. The remaining modes are propagative cavity modes, which we call “photonic”. The Casimir energy contains two main contributions, one coming from the plasmonic, the other from the photonic modes. Surprisingly we find that the plasmonic contribution to the Casimir energy becomes repulsive for intermediate and large mirror separations. Alternatively, we discuss the common surface plasmon defintion, which includes only evanescent waves, where this effect is not found. We show that, in contrast to an intuitive expectation, for both definitions the Casimir energy is the sum of two very large contributions which nearly cancel each other. The contribution of surface plasmons to the Casimir energy plays a fundamental role not only at short but also at large distances.
Selection of theoretical parameter characterizing scavenging activity of antioxidants on free radicals
Authors: Zhang Hong‐Yu
Published: May 2007

Semiempirical quantum chemistry method Austin Model 1 (AM1) was employed to calculate the theoretical parameters of 15 antioxidants. Such parameters as bond order, bond length, and the difference of heat of formation (ΔHOF) between the antioxidant and its phenolic free radicals were obtained. Through correlating with previous experimental results ΔHOF was proven to be a proper parameter (r=0.9491) to characterize the free radical‐scavenging activity of antioxidants, but bond order and bond length were not able to represent the antioxidant's ability to scavenge free radicals. By comparing the results calculated by different semiempirical methods, including AM1, Modified Neglect of Diatomic Overlap, and Parametric Method 3, AM1 was found to be the best for calculating ΔHOF.