bluuebunny/crossref_metadata_2025 huggingface dataset:
Trade‐offs and seasonal variation in territorial defence and predator evasion in the European Robin Erithacus rubecula
Authors: Dunn Michael , Copelston Michael , Workman Lance
Published: December 2004

The low incidence of intraspecific combat in territorial systems has traditionally been accounted for by theories that emphasize the bio‐energetic advantages or the diminished risk of injury of threat display posture when compared with combat. Recently, however, it has been suggested that territory‐holding passerines engaging in highly aggressive defensive behaviour are likely to pay a cost in terms of reduced vigilance for avian predators. To examine this further, two defensive options (combat and threat display) were evoked and observed in territorial European Robins Erithacus rubecula, in both winter and summer. It was found that Robins that engaged in combat during simulated territorial intrusion were significantly slower to react to a stuffed Sparrowhawk Accipiter nisus, than those eliciting threat display. Therefore, the decreased vigilance in escalated fighting may result in higher vulnerability to predation, and this might help, in part, to explain why threat display is favoured over direct combat. Moreover, the mean time to evade the predator was significantly longer in summer than in winter in threat‐displaying Robins. In addition to this finding, a clear difference in the type of behaviour adopted between the seasons was observed, with lower incidence of combatative response during the winter months. This difference in response to the appearance of a predator is discussed in relation to reduced levels of safe cover, a reduction in the availability of alternative prey during the winter months and to seasonal fluctuations in plasma androgen levels.
The first record of Brown Skua Catharacta antarctica in Europe
Authors: Votier Stephen C. , Bearhop Stuart , Newell Richard G. , Orr Kate , Furness Robert W. , Kennedy Martyn
Published: December 2004

Evidence from mtDNA suggests that two skuas, one discovered in the Scilly Islands Cornwall in October 2001, the other in Glamorgan in February 2002, belong to the Brown Skua group Catharacta antarctica– a species not previously recorded in the North Atlantic. These molecular data do not exclude the possibility of either bird being a hybrid between Brown Skua and South Polar Skua C. maccormicki, but population estimates suggest that this is unlikely. More importantly, biometrics show that the Glamorgan bird is much smaller than hybrids but matches Falkland Skua C. a. antarctica. The distributions of C. antarctica subspecies at sea are not well known, but the discovery of two of these birds in the UK suggests that they may wander more extensively than previously thought.
Temporal changes in the breeding ecology of European Turtle Doves Streptopelia turtur in Britain, and implications for conservation
Authors: Browne Stephen J. , Aebischer Nicholas J.
Published: December 2004

The migratory European Turtle Dove Streptopelia turtur has undergone a 69% decline in population size and a 25% contraction in breeding range in Britain over the last 30 years. An investigation of the breeding ecology of this summer visitor was undertaken in 1998–2000 at two study sites in East Anglia, England. The only previous study of Turtle Dove reproduction in Britain provided pre‐decline data for comparison with the current situation in a modern agricultural environment. Territory sizes ranged from 1.91 to 3.08 ha, were established in areas with scrub, hedges and woodland and contained less cropped land than expected from its availability. The majority of nests were sited 1–3 m above ground level within thorny bushes, particularly Hawthorn Crataegus monogyna. Nests found by radiotelemetry were significantly higher above ground level and were found in greater numbers than expected in woodland and coniferous trees than those found by cold searching, which were lower and found predominantly in hedges and thorny bushes. Turtle Dove nest success rate averaged 53% during incubation and 65% during the nestling stage, so that only 35% of nests successfully produced young. A comparison with data collected during the 1960s showed that Turtle Doves today have a shorter breeding season and consequently produce about half the number of clutches and young per pair than formerly. A simple simulation model suggested that the reduction in productivity alone would lead to a population decline of 17% per annum. This study suggests that the recovery of Turtle Doves in Britain is dependent upon the provision and sympathetic management of nesting and foraging habitats. The current arrangements for set‐aside and agri‐environmental schemes provide the framework for delivering these requirements.
Breeding upwards when climate is becoming warmer: no bird response in the French Alps
Authors: Archaux Frederic
Published: December 2004

Altitudinal shifts in distribution were investigated in forest breeding birds, along two elevational gradients in the French northern and southern Alps, from counts repeated at exactly the same locations in the 1970s and the 2000s. Significant shifts were reported for eight of 24 species in the northern alpine site (five downwards, three upwards) and for two of the 17 species in the southern site (one downwards, one upwards). Apart from the Crested Tit Parus cristatus, which shifted significantly downwards at both sites, altitudinal shifts were not significantly correlated between sites. Bird communities did not shift their distribution upwards despite a 2.3 °C increase in spring temperatures in the two study areas. These results suggest that bird distributions by altitude have not yet been affected by climatic warming, and that most specific elevational shifts are probably related to site‐specific factors.
Variation in breeding success among reintroduced island populations of South Island Saddlebacks Philesturnus carunculatus carunculatus
Authors: Hooson S. , Jamieson I. G.
Published: December 2004

South Island Saddlebacks Philesturnus carunculatus carunculatus were once found throughout the South Island of New Zealand, but by the early 1960s were confined to the island of Big South Cape, in the extreme south of the country. All subsequent reintroduced populations of South Island Saddlebacks are derived from 36 surviving birds from this relict population. The aim of this study was to compare the breeding success of three recently reintroduced populations of Saddlebacks relative to their distance from, and habitat similarity to, the relict population. The three study islands show a latitudinal cline with Ulva, Breaksea and Motuara Islands located 60, 190 and 810 km north of Big South Cape, respectively. Saddlebacks on Ulva and Breaksea appeared to prefer to establish breeding territories in coastal scrub, the dominant habitat feature of Big South Cape. The area of coastal scrub habitat was much smaller on Motuara, where breeding territories were instead scattered through broadleaf forest habitat. Nesting success, calculated using Mayfield's method, was significantly greater on Ulva (73%) than on Breaksea (32%) or Motuara (19%) owing primarily to higher egg fertility and hatching success. Although egg failure rates were highest on Motuara, the island least similar to Big South Cape, they were also relatively high on Breaksea where the habitat was similar to Ulva and Big South Cape. Therefore, the results only partially support the hypothesis that nesting success should decrease with increasing habitat difference associated with increasing latitudinal distance from the source population. The data from this 1‐year study lay the groundwork for examining further hypotheses on the effects of reintroducing endangered species outside their contemporary range, but within their historical range.
Comparing areas of suitable habitats along travelled and possible shortest routes in migration of White‐naped Cranes Grus vipio in East Asia
Authors: Fujita Go , Hong‐Liang Guan , Ueta Mutsuyuki , Goroshko Oleg , Krever Vladimir , Ozaki Kiyoaki , Mita Nagahisa , Higuchi Hiroyoshi
Published: December 2004

Many migratory species take detours when migrating from their breeding to wintering grounds rather than following the shortest route available. To test whether the distribution of potentially suitable habitats might be a factor causing the use of less direct detours during migration, we analysed the migratory routes of five White‐naped Cranes Grus vipio satellite‐tracked from central–east Russia, and compared the total area of wetlands and grasslands along the migratory routes travelled by the Cranes with that along the shortest possible routes to the Cranes’ wintering grounds. All five Cranes made an easterly detour, and the distance ratio of the routes used by Cranes to the shortest possible route was 1.13 ± 0.03 sd. Based on National Oceanic and Atmospheric Administration satellite images, we demonstrate that the area of wetlands and grasslands along the migration routes travelled by Cranes was greater than along the shortest possible routes.
Survival estimates of adult Sooty Terns Sterna fuscata from Bird Island, Seychelles
Authors: Feare Chris J. , Doherty Paul F.
Published: December 2004

Sooty Tern Sterna fuscata populations on the Seychelles Islands have been exploited for human consumption of their eggs for at least the last 75 years. This has led to concern about possible declines in these populations. To address these concerns, the Seychelles Government has instituted a research and management plan to ensure the sustainability of the egg harvest. The harvest model, upon which current harvest regulations are based, was constructed with an assumed adult survival rate because there are no published Sooty Tern survival rate estimates. We fill this knowledge gap and address this assumption. We estimated adult Sooty Tern survival to be 0.91 (SÊ = 0.01), which was close to the estimate used in the model. This estimate is also comparable with other seabird survival estimates. In the future this estimate could be improved with higher recapture rates. In addition, further advances in models for estimating probabilities of age at first breeding, prebreeder survival and population growth should be used to best effect, by making appropriate improvements to the ring search protocol, to provide further feedback to the management programme.
Eine Geisterbeschwörung
Authors: Krätz Otto
Published: December 2004

Schon immer haben Nahrungsmittelskandale die Aufmerksamkeit des Publikums gefesselt. So auch der sogenannte Strychnin‐Skandal im vorigen Jahrhundert. Damals tauchte der Verdacht auf – woher ist nicht genau bekannt ‐, daß englische Brauereien ihrem berühmten Pale Ale zur Abrundung des bitteren Geschmacks Strychnin zusetzten. A. W. Hofmann und Justus von Liebig halfen den Brauern mit Gutachten bei der Auseinandersetzung mit dem “Strychnin‐Gespenst” ‐ nicht ganz ohne Belohnung, wie der folgende Bericht zeigt.
Chomische Fehler auf chemischen Briefmarken
Authors: Heilbronner Edgar , Miller Foil A.
Published: December 2004

„You can observe a lot by just watching.”︁ (Yogi Berra [2]).
Chirale Arzneimittel. Scale‐up, Kontrolle und deren Bedeutung für die pharmazeutische Forschung
Authors: Federsel Hans‐Jürgen
Published: December 2004

Man weiß heute, daß optische Isomere pharmakologisch aktiver Verbindungen sehr unterschiedliche Eigenschaften z. B. in Bezug auf ihre physiologische Aktivität, ihren Wirkungsmechanismus, ihre Toxizität und Nebenwirkungen haben können. Deshalb wird vom Produzenten mehr und mehr verlangt, daß die Konzentrationen der optischen Isomere mit unerwünschten Nebenwirkungen in Arzneimitteln einen festgelegten und oft sehr niedrigen Wert nicht überschreiten dürfen. Im vorliegenden Beitrag werden die Methoden zur Herstellung optisch aktiver Zielmoleküle nach folgender Einteilung beschrieben: 1. Seperationsverfahren, z. B. Racemattrennungen durch Kristallisation, Chromatographie oder mit Hilfe von Enzymen, 2. Synthesen ausgehend von Verbindungen aus dem „chiral pool”︁, 3. Synthesen mit synthetisch hergestellten chiralen Bausteinen, 4. asymmetrische Synthesen. Natürlich ist die Herstellung stereochemisch definierter Verbindungen immer mit einem zusätzlichen Aufwand bei der Entwicklung effizienter Prokutionsprozesse verbunden. Doch das immer breitere Angebot an optisch reinen Synthesebausteinen sowie die Entwicklung asymmetrischer Synthesen, die sich auch für industrielle Maßstäbe eigen und klassische Verfahren ergänzen, versprechen die auftretenden Probleme erheblich zu reduzieren.
Präparative Verwendung von Mannich‐Basen von Hydroxy‐indolen als Alkylierungsmittel. 4. Mitteilung über synthetische Indol‐Verbindungen [1]
Authors: Troxler Franz
Published: December 2004

The MANNICH bases 4‐dimethylaminomethyl‐5‐hydroxy‐indole and 7‐dimethylaminomethyl‐6‐hydroxy‐indole are suitable agents for alkylating C‐acidic compounds such as nitroalkanes and ethyl formamido‐malonate. The products obtained have been transformed into (substit.) aminoethyl derivatives or amino‐acids containing the basic side‐chain in the benzene nucleus and which are, therefore, isomeric to tryptamines and tryptophans.
Über die Hemmung der Leber‐ und der Muskelaldolase durch Glycerinaldehyd‐3‐phosphat. 15. Mitteilung über Aldolasen [1]
Authors: Hotz R. , Leuthardt F.
Published: December 2004

The kinetics of the inhibition of rabbit muscle and liver aldolase by DL‐glyceraldehyde‐3‐phosphate have been studied.

The inhibition is of the non‐competitive type.

The ternary enzyme‐substrate‐GAP‐complex shows a residual enzyme activity, muscle aldolase‐FDP showing the highest and liver aldolase‐F‐1‐P the lowest activity.

The dissociation constant K0′ (ESI ⇄ ES+I) has been determined on the assumption of quasi‐equilibrium kinetics.
Säurekatalysierte Isomerisierung von α,β‐Cyclopropyl‐oxiranen
Authors: Ohloff G. , Giersch W.
Published: December 2004

Using the epoxycarane derivatives 3 and 6, the behaviour of α,β‐epoxycyclopropy. compounds in the presence of acids has been examined and the main reaction products elucidated Proposals for the reaction mechanism are made.
Echange d'oxygène entre des p‐benzoquinones substituées et l'eau
Authors: Dahn H. , Aubort J.‐D.
Published: December 2004

The velocity of oxygen exchange between several substituted p‐benzoquinones and H218O has been measured at 25°C in neutral tetrahydrofuran containing 2 to 5% water. Halogen substituents accelerate the exchange (Cl > Br), methyl groups slow it down. The reaction was found to be second or third order in [H2O].
Pyridinderivate als Komplexbildner IX Die Stabilitätskonstanten von Komplexen mit (a) 2‐aminomethyl‐pyridin, (b) 6‐methyl‐2‐aminomethyl‐pyridin, (c) 2‐pyridylhydrazin, (d) 2,2′‐dipyridylamin und (e) 1‐(α‐pyridylmethylen)‐2‐(α′‐pyridyl)‐hydrazin
Authors: Anderegg G.
Published: December 2004

The complex formation of the ligands given in the title has been investigated using potentiometric measurements at ionic strength 0,1 and 20°C. The results are discussed in comparison with the known values and with those of similar ligands.
The Total Synthesis of Ipalbidine and Ipalbine
Authors: Wick A. E. , Bartlett P. A. , Dolphin D.
Published: December 2004

Eine Totalsynthese des Hexahydroindolizin‐Alkaloids Ipalbidin (7) und seines β‐D‐Glucosids Ipalbin (1) wird beschrieben. Der zentrale Syntheseschritt besteht aus einer N‐Acylierung des vinylogen Amidsystems 3, gefolgt von einer internen Kondensation zum pentasubstituierten Pyridon 4. Die spektralen Daten von synthetischem Ipalbidin bzw. Ipalbin sind identisch mit denjenigen der entsprechenden natürlichen Verbindungen. Auf Grund des Vergleichs von optischen Drehugen wird ermittelt, dass Ipalbidin in der Natur in racemischer Form vorliegt.
Oxidation and Reduction of 8,9‐Anhydroerythronolide B 6,9‐Hemiacetal
Authors: Kurath P. , Egan R. S.
Published: December 2004

Die Reaktion von Erythronolid B mit Säure lieferte das bisher unbekannte 8, 9‐Anhydroerythronolid‐B‐6, 9‐hemiacetal. Diese Verbindung wurde oxydativ in (8S, 9S)‐8, 9‐Anhydroerythronolid‐B‐6, 9‐hemiacetal 8,9‐epoxid und (8S)‐8‐Hydroxyerythronolid B umgewandelt. Durch Reduktion der Doppelbindung im Enoläther wurde das (9S)‐9‐Dihydro‐6, 9‐O‐anhydro‐erythronolid B erhalten.
Methoxokomplexe drei‐, vier‐ und fünfwertiger Zentralatome
Authors: Gut R. , Schmid Eduard , Serrallach Jorge
Published: December 2004

The complex formation with CH3O− of AsIII, SbIII, GeIV, NbIV, SeIV, TeIV, TiIV, SnIV and MoV has been investigated in absolute methanolic solutions containing (CH3)4NCl, LiCl, or Lithiumtosylate (μ = 1; 20.0°) by means of pH‐titrations. The relations between the stoichiometry of the reactions and the shape of the buffer regions, as well as the concentration‐dependance of these buffer regions are discussed.
Utilisation d'ylides du phosphore en chimie des sucres VII. Synthèse de sucres ramifiés des types «streptose» et «apiose». Communication préliminaire
Authors: Tronchet J. M. J. , Bourgeois J.‐M. , Chalet J.‐M. , Graf R. , Gurny R. , Tronchet Mme J.
Published: December 2004

A new high‐yielding route to branched‐chain sugars of the streptose or the apiose type having at the branching point a configuration epimeric with that which would be obtained by the classical synthesis using Grignard reagents is described. The main steps are the preparation of branched‐chain unsaturated cyano sugars by reaction of cyanomethylene triphenylphosphorane with keto sugars and the cis‐dihydroxylation (KMnO4) of the so obtained cyano sugars. The cis and the trans isomers of a series of cyanovinylidenic sugars have been separated and the stereodependence of the long‐range coupling constants in this class of compounds has been examined.
Darstellung und Eigenschaften von 1,2,3,4,5,6‐Hexahydro‐8‐hydroxy‐3‐methyl‐3‐benzazocin
Authors: Pecherer B. , Humiec F. , Brossi A.
Published: December 2004

In continuation of our search for new analgesics, 1,2,3,4,5,6‐hexahydro‐8‐hydroxy‐3‐methyl‐3‐benzazocine has been prepared.

Anmerkung der Redaktion. Die Bezeichnung des Grundskeletts der Verbindungen 2, 14, 15, 16 und 17 als 3‐Benzazocin entspricht den I.U.P.A.C.‐Nomenklaturregeln nicht; sie sollte lauten: Benz[d]azocin. Auf Wunsch der Verfasser, welche eine Abweichung von der in früheren Veröffentlichungen verwendeten Nomenklatur (vgl. [1]) vermeiden möchten, ist die Redaktion jedoch bereit, die beanstandete Bezeichnung beizubehalten.
23S state of helium
Authors: Ermolaev A. M. , Sochilin G. B.
Published: December 2004

A rapidly convergent method, which has previously been applied to the ground state of the helium atom, has been extended to excited S states. This method is based on an expansion of the wave function in powers of \documentclass{article}\pagestyle{empty}\begin{document}$ \sqrt {r_1^2 + r_2^2} $\end{document}, ln (r + r), \documentclass{article}\pagestyle{empty}\begin{document}$ w = r_{12} /\sqrt {r_1^2 + r_2^2} $\end{document}. Different effective nuclear charges are used for the inner and the outer electrons. Very satisfactory results are obtained for expectation values of various operators.
Cluster expansion analysis for delocalized systems
Authors: Čížek J. , Paldus J. , Šroubková L.
Published: December 2004

The general formulas which are convenient for cluster analysis of a configuration interaction wave function are presented. These formulas are then used for cluster analysis of the “complete” configuration interaction wave functions of the π‐electronic models of benzene and butadiene obtained with a semiempirical method of the Pariser–Parr–Pople type using three different parameterizations. For butadiene the calculations are carried out with Hückel, Hartree–Fock, and Brueckner molecular orbitals. The results clearly indicate that Sinanoǧlu's statement [1, 2], concerning the relative unimportance of the linked parts of the tetraexcited state coefficients in the ci expansion, is justified for these delocalized systems.
Polarization contribution to the dipole moment and infrared spectrum intensity of the benzene–iodine complex
Authors: Mantione Marie‐José
Published: December 2004

Polarization is shown to play a non‐negligible role in two properties of the ground state of benzene–iodine type complexes: their dipole moment, and the halogen infrared spectrum. These results, compared with preceding results concerning π–π complexes, suggest that the ground‐state properties of charge‐transfer complexes should not be interpreted exclusively by the usual resonance mode.
Zero‐field splitting in phosphorescent triplet states of aromatic hydrocarbons IV. Phenyl naphthalenes
Authors: Orloff M. K. , Brinen J. S.
Published: December 2004

The zero‐field splitting parameters D, E, and D* are calculated theoretically for four phenyl naphthalenes. Esr measurements show that the theoretical calculations are in good agreement with experiment. Comparison of the theoretical and experimental results gives some insight into the geometry of these molecules in their lowest triplet state.
Full configuration interaction for the benzyl radical
Authors: Kuprievich V. A. , Kruglyak Yuri A. , Mozdor E. V.
Published: December 2004

The electronic structure of the benzyl radical in its ground state has been computed using a model Hamiltonian due to Pariser–Parr with full configuration interaction as well as with different truncated configurational sets built on SCF open‐shell orbitals. The correlation energy corresponding to this model was found to be equal to –0.929722 eV. With the singly excited configurations only 18% of this energy is taken into account. By extending the basis to include the doubly excited configurations one can account for 94% of the correlation energy. An analysis of the accuracy of the proton hyperfine splitting calculation caused by inaccurate computation of the wave function is given. If only singly and even doubly excited configurations are taken into account one cannot hope to obtain splittings with an accuracy of more than 0.5 g. Inclusion of triply excited configurations lowers this error by one order. In addition, the use of the simple McConnell relation may lead to an error in splitting calculations of no less than 1.5 g.
Small, simultaneous adjustments of orbital exponents in LCAO–MO–SCF calculations using self‐consistent perturbation theory
Authors: Vladimiroff T.
Published: December 2004

Self‐consistent perturbation theory is introduced to facilitate making small, simultaneous variations in orbital exponents. This is accomplished by interpreting these variations as perturbations on the quantum mechanical system. The minimum‐energy condition yields a set of linear equations for the desired exponential corrections.
Ab initio calculations, using a small Gaussian basis set, of the electronic structure of the sulphate ion
Authors: Hillier I. H. , Saunders V. R.
Published: December 2004

Ab initio molecular orbital calculations of the electronic structure of the sulphate ion have been performed in which three Gaussian‐type functions are used to simulate each member of a minimal basis of Slater‐type orbitals. Comparative calculations on H2S show that such a basis excellently reproduces the properties of the valence electrons given by calculations in a Slater basis. The expansion of the basis by the addition of sulphur 3d orbitals results in a large decrease in the molecular energy (1 a.u.) and has a pronounced effect on the ordering and energy of the molecular orbitals. The results of a number of semiempirical schemes are discussed in the light of these results.
The generalized separated electron pair model. 1. An application to NH3
Authors: Robb M. A. , Csizmadia I. G.
Published: December 2004

The utility of the separated electron pair (SEP) model (strongly orthogonal geminals) is examined quantitatively, for pyramidal and planar nuclear configurations of the NH3 molecule. The best SEP wave function computed for each species is capable of recovering about half of the correlation energy obtained by a fairly accurate configuration interaction (CI) calculation, (corresponding to roughly 25% of the total molecular correlation energy). It is illustrated that the model can be systematically extended with only a modest effort to yield more accurate results (about 40% of the total correlation energy). The fact that the corrections to the SEP model have a simple physical interpretation suggests that this model may be a useful starting point for “brute force” CI calculations on larger chemical systems.
Le Couplage Vibronique dans une Chaine Linéaire de Molecules Etudié par une Méthode Auto‐Cohérente
Authors: Tallet A. , Garcia‐Sucre M. , Lefebvre Et R.
Published: December 2004

We describe the correlation diagram of a linear crystal, in the traditional framework of the vibronic coupling. All lattice normal modes, except the symmetrical mode, are coupled to the excitation transfer. We therefore propose an iterative method, where every mode “sees” an effective coupling arising from the interaction of the other modes with the electronic excitation. This method is applied to a simple case (the pentamer) and the results are compared with the exact solution. In the weak coupling case this procedure gives the vibronic band structure and in the strong coupling case, the electronic band accompanied by vibrational excitations. These results show that the method employed represents an interpolation approach.
On energy bounds derived from the conjugate eigenvalue problem
Authors: Robinson Peter D. , Epstein Saul T.
Published: December 2004

An upper bound for E0, which has been derived from the conjugate eigenvalue problem by Hall, is discussed. It is emphasized that the bound is only guaranteed when V is negative‐definite. An alternative bound is presented which is free from this restriction, and the underlying iterative procedure is given. Hall's result is generalized to admit internuclear distances, and the theory is illustrated by a one‐dimensional system with delta‐function potentials. Some disadvantages of the approach are mentioned.
A study of dynamic quadrupolar and octupolar excitations and calculations on excited d and f states of atom and ions: He‐sequence
Authors: Moitra R. K. , Mukherjee P. K. , Sengupta S.
Published: December 2004

The quadrupolar and octupolar distortion of the ions in the He‐sequence caused by an external electro–magnetic field has been studied by a variation–perturbation method in the Hartree–Fock scheme. For certain frequencies singularities appear in the response of the system to the perturbation. Approximate representations for the excited d and f states have been obtained from a study of these resonances. Such a perturbation calculation has the advantage that representations of the different excited states are obtained independently. The orthogonality to all the lower lying levels of the same symmetry is not required. The only source of inaccuracy implicit in the procedure lies in the improper consideration of the inter‐electronic interaction. This is corrected for by an independent calculation, which is again formulated in terms of a perturbation treatment. The resulting wave functions for the excited states are accurate in the Hartree–Fock model. Expectation values of several operators have been calculated with these corrected wave functions.
Critical point, singularities and extrapolations in the helium iso‐electronic sequence
Authors: Brändas E. , Goscinski O.
Published: December 2004

The Z‐expansion of two‐electron systems is analyzed with the Padé technique with emphasis on establishing analytical properties of the function E(Z) formally associated with the power series expansion. The concept of critical point in this connection is stressed. For this sequence it occurs at Zc = 0.911246 with E(Zc) = −0.415184. The structure of E(Z) for Z < Zc is investigated.

The use of Padé approximants to extrapolate values of electron affinities is emphasized.
Theoretical study of a 1 : 1 complex between quinone and hydroquinone
Authors: Sundaram K. , Purcell William P.
Published: December 2004

The Variable Electronegativity Pariser–Parr–Pople method has been successfully applied to calculate the potential energy curve for the formation of a 1: 1 complex between quinone and hydroquinone. A consistent evaluation of core and electronic repulsion integrals is important to obtain a meaningful curve. A computationally simple procedure has been suggested for separating interactions due to electron exchange between the components from other intermolecular interactions. In agreement with experimental deductions the preferred configuration for the quinone‐hydroquinone complex is found to be one in which the molecules are in parallel planes with their C—O bonds parallel. The equilibrium separation between the molecular planes is found to be 2.3 Å and the stabilization energy in this position is 1.2 eV. In this equilibrium position forces due to electron exchange constitute the major contributing factor to the stability of the complex.
Calculation of excited states of H2O and NH3 by the one‐center expansion approximation
Authors: Hatano Yasuyo , Nomura Tsutomu , Tanaka Kiyoshi
Published: December 2004

The potential energy curves with respect to the bond angle are calculated for some excited and ionized states of the H2O and NH3 molecules by the use of the one‐center expansion SCF MO and the improved virtual orbital approximations. The calculated equilibrium bond angles and force constants of bending motion are in good agreement with the experimental results.
CNDO calculation of polarizabilities including polarization functions in the basis set
Authors: Svendsen E. Nørby , Stroyer‐Hansen T.
Published: December 2004

Electric polarizabilities are calculated by solving the first‐ and second‐order perturbation equations through a variational procedure. Satisfactory numerical results are obtained for a number of molecules using the CNDO approximation with an extended basis set.
Method of recurrent construction of Löwdin spin‐adapted wave functions. III. Löwdin basis and its permutation symmetry: Evaluation of overlap integrals
Authors: Panin A. I.
Published: December 2004

The Löwdin basis functions are introduced and their permutation symmetry is studied in detail. A simple relation between the Löwdin basis and the orthogonal basis constructed by means of Young–Yamanouchi units is established. Both analytical and recurrence formulas for the overlap integrals of the Löwdin and some relevant auxiliary functions are derived. The symmetry of the overlap matrix of the Löwdin basis functions is briefly discussed.
Ab initio studies of hydrogen bond formation in methyl cyanide or methyl isocyanide and methanol systems
Authors: Tang Ting‐Hua , Fu Xiao‐Yuan
Published: December 2004

CH3CN ⃛ HOCH3 and CH3NC ⃛ HOCH3 hydrogen‐bonded systems have been studied theoretically by ab initio MO methods using a 4–31 G basis set at their equilibrium geometries. The stabilization energies of these hydrogen bonds are 5.4 and 5.9 kcal/mol, respectively. The nature of these hydrogen bonds is discussed in the light of frontier orbital theory and the topological properties of the charge density of the chemical bond.
A theoretical study of C4H5N isomers: Comparison of cyano and isocyano as substituents
Authors: Lien Min H. , Hopkinson Alan C.
Published: December 2004

Ab initio molecular orbital calculations using a 3‐21G basis set have been used to optimize geometries for pyrrole, CH3(X)CCH2, CH3(H)CCHX (both cis and trans), c‐C3H5X, and CH2CHCH2X, where X is CN and NC. In all the alkenyl derivatives methyl groups are found to adopt the conformation in which the methyl hydrogen eclipses the double bond. 6‐31G*∥3‐21G level calculations show the alkenyl cyanides to be of similar energy to pyrrole, but the isocyanides are ∼20 kcal mol−1 higher in energy. For both substituents the cyclopropyl derivatives are higher in energy by ∼10 kcal mol−1. At the 6‐31G* level ring strain is 27.7 kcal mol−1 for the cyanide and 30.6 kcal mol−1 for the isocyanide. Data on the relative energies of RCN and RNC are compared when R is (i) a saturated hydrocarbon, (ii) an unsaturated hydrocarbon, (iii) an α‐carbenium ion, (iv) an allyl cation, and (v) an α‐carbanion.
Efficient method for computation of representation matrices of the unitary group generators
Authors: Duch W.
Published: December 2004

The representation matrices of the unitary group generators Ek1 are equivalent to the representation matrices of cyclic permutations (k, k ± l, …, l ∓ 1, l). A method is presented for simultaneous computation of matrices corresponding to all different generators at a cost of less than one multiplication per nonzero element. The number of operations necessary for calculation of individual matrices for single generators or for products of two generators is at most proportional to the number of matrix elements of the final matrix. This approach eliminates the need to store the representation matrices in CI calculations.
Diagrammatic analysis and application of the coupled cluster response approach to ground‐state expectation values
Authors: Nooijen Marcel , Snijders Jaap G.
Published: December 2004

The response approach to couple cluster (CC) expectation values devised by Monkhorst and the normal coupled cluster method (NCCM) discussed by Arponen and Bishop are considered from a diagrammatic point of view. The perturbative diagrammatic content of the operator that parametrizes the NCCM bra state is discussed in detail. The method is applied to the calculation of the one‐particle reduced density matrix of the Be atom and the HF molecule for different values of the internuclear distance. Various contributions to the total energy obtained in the NCCM framework are compared to results from accurate multireference configuration interaction calculations. Such a comparison is shown to provide a much more stringent test on the accuracy of the CC formalism than will a comparison of total energy alone. © 1993 John Wiley & Sons, Inc.
Localized functions on a circle
Authors: Rees D. , Hall G. G.
Published: December 2004

The derivation of hybrids as localized equivalent functions in the plane is discussed using the simultaneous eigenfunctions of the x and y position operators, as represented in a finite basis. It proves helpful, initially, to use complex exponentials as basis functions, but the transformation to a real basis is made later. The introduction of alias functions to produce commuting matrices is described. Full results are obtained for any number of functions in the plane. © 1995 John Wiley & Sons, Inc.
Inversion of spectral absorption in the optically complex coastal waters of the Mid‐Atlantic Bight
Authors: Schofield Oscar , Bergmann Trisha , Oliver Mathew J. , Irwin Andrew , Kirkpatrick Gary , Bissett W. Paul , Moline Mark A. , Orrico Cris
Published: December 2004

Recent advances in hydrologic optics offer the potential for quantitative maps of inherent optical properties, which can be inverted into optically significant constituents. During summer experiments in the Mid‐Atlantic Bight (MAB) a procedure to invert bulk absorption measurements from off‐the‐shelf technology was developed. The inversion provides optical concentration estimates of phytoplankton, colored dissolved organic matter (CDOM), and detritus. Inversion estimates were validated against chlorophyll fluorescence, filter pad absorption, and phytoplankton pigment measurements. The inversion could account for up to 90% of the observed variance in particulates, CDOM, and detritus. Robust estimates for phytoplankton community composition could be achieved but required constraints on the inversion that phytoplankton dominate the red light absorption. Estimates for the composition, as indicated by spectral slopes, for CDOM and detritus were not robust. During the summer months in nearshore waters of the MAB, total absorption was almost equally associated (±10%) with phytoplankton, detritus, and CDOM, and the regions of variability were associated with major frontal boundaries. The variance between particulates, CDOM, and detritus varied spatially and with year; which precluded robust correlations.
Bow shock's geometry at the magnetospheric flanks
Authors: Merka J. , Szabo A.
Published: December 2004

The database of IMP 8 bow shock crossings was used to investigate properties of the bow shock's cross section between 10 and 15 RE tailward of Earth in response to selected upstream and magnetospheric parameters. Best‐fitted ellipses were derived for each parameter subset and analyzed. We have found that for average solar wind conditions, the shock's cross section moves in the north‐south directions by 3.8 RE when the dipole tilt changes from sunward to antisunward orientations. Comparisons with results provided by global three‐dimensional MHD simulations of the magnetosphere have shown that the tilt angle effect is likely to be also important for the estimation of the dayside shock wave's position. We have found the orientation of the IMF with respect to the solar wind flow, expressed by the angle θBv, to influence the size and stability of the shock shape/position. The observed Mach number dependence agreed with previous studies and no other significant IMF‐induced asymmetries were found.
Seismic ground motions from a bolide shock wave
Authors: Langston Charles A.
Published: December 2004

An intensely brilliant bolide accompanied by an audible sonic boom occurred on the night of 3 November 2003 (∼2150 LT or 4 November 2003, 0350 UT) in northeastern Arkansas. The sonic boom was well recorded by 22 three‐component stations of the Center for Earthquake Research and Information Cooperative Seismic Network. Arrival times and wave polarizations were used to reconstruct the acoustic wave front propagating across the network and to estimate trajectory parameters of the bolide. A grid search location technique constrains the trajectory and gives a reference height of 50–100 km above the southern edge of the network, an azimuth of propagation of 270°–290° toward the northwest and a plunge of 38°–48° downward. The trajectory and date of the bolide event are consistent with a Taurid shower meteor. Transient ground motions from the sonic boom were studied using plane wave, Cagniard‐deHoop, and propagator matrix theory for an incident pressure pulse impinging on a layered elastic Earth model. General characteristics of the vertical and radial polarization and wave frequency content require acoustic coupling within a thin (∼10 m) near‐surface layer with low P wave (∼0.25 km/s) and S wave (∼0.125 km/s) velocities. Ground motions are generally confined to this near‐surface layer, are not sensitive to deeper Earth structure within the Mississippi embayment unconsolidated sediments, and display both “leaky” mode PL (a type of dispersed, P‐type seismic wave) and “locked” mode Rayleigh wave propagation. Acoustic wave/ground motion coupling studies may be a useful way to analyze near‐surface site responses to determine velocity structure in earthquake shaking hazard studies.
Nonseasonal sea level variations in the Japan/East Sea from satellite altimeter data
Authors: Choi Byoung‐Ju , Haidvogel Dale B. , Cho Yang‐Ki
Published: December 2004

A merged TOPEX/POSEIDON and ERS‐1/2 altimeter data set is used to estimate nonseasonal variations of sea surface height (SSH) in the Japan/East Sea (JES) from October 1992 through February 2002. The altimeter data have a good correlation (0.95) with tide gauge data in the western JES. The nonseasonal variability of the SSH is higher in the southern warm region than in the northern cold region. The root‐mean square value of the nonseasonal SSH is 5–10 cm in the southern area, whereas it is about 4 cm in the northern area. Empirical orthogonal function analysis of the nonseasonal SSH shows the first mode to be related to intraseasonal oscillations over the entire JES and the second mode to interannual path variations of the Tsushima Warm Current (TWC). The path change of the TWC is responsible for the high variability of SSH in the southern region.
Characterization of the Ugandan inshore waters of Lake Victoria based on temperature‐conductivity diagrams
Authors: Cózar Andrés , Bracchini Luca , Dattilo Arduino , Loiselle Steven , Azza Nicholas
Published: December 2004

Temperature‐conductivity diagrams are shown as a valid instrument to analyze the hydrographic structure of freshwater ecosystems, even along the surface waters. We put this method in practice in the Ugandan inshore waters of Lake Victoria. A complementary parameter (T‐C anomaly) was used to differentiate between upland water intrusions. The relative value of the T‐C anomaly provided information about the nature of the water intrusions and showed a considerable correlation with the biological characteristics of the water masses. The results indicated that the connections between catchment attributes, water characteristics, and biological community are quite direct in the inshore waters of Lake Victoria.
Immunoglobulins in saliva of preterm and full‐term infants.
Authors: Wan A. K. L. , Seow W. K. , Purdie D. M. , Bird P. S. , Walsh L. J. , Tudehope D. I.
Published: December 2004

The aim of this longitudinal study was to determine salivary levels of total IgA, IgG and IgM in 84 preterm and 214 full‐term infants, from birth to 18 months of age. Unstimulated whole saliva was collected from each infant at birth, and subsequently at 3‐monthly intervals. Immunoglobulin levels were estimated using an ELISA technique. At birth, IgA was detected in 147/214 (69%) full‐term infants but only 47/84 (56%) preterm infants (P < 0.01). In the case of IgG, 61% of full‐term and 56% of preterm infants showed detectable levels, whereas IgM was found in 71% and 73%, respectively. Levels of IgA and IgG rose from birth to 18 months, whereas IgM levels did not change significantly. Increases in salivary levels of IgA were associated with introduction of solid foods (P < 0.001), as well as tooth eruption (P < 0.001). Our results indicate that the majority of full‐term and preterm infants are orally immunocompetent at birth.
Helicobacter pylori and Campylobacter rectus share a common antigen
Authors: Tanabe S. , Hinode D. , Yokoyama M. , Fukui M. , Nakamura R. , Yoshioka M. , Grenier D. , Mayrand D.
Published: December 2004

Aim:  The aim of this study was to investigate the presence of antigens with immunological cross‐reactivity in periodontopathogenic bacteria and Helicobacter pylori, the pathogen associated with gastritis and peptic ulcers in human.

Materials and methods/Results:  Among the putative periodontopathogens tested (Actinobacillus actinomycetemcomitans, Campylobacter rectus, Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia and Treponema denticola), cross‐reactive bands were only detected in C. rectus by SDS–PAGE/Western immunoblotting analysis using a polyclonal antibody directed to H. pylori cells. One of these cross‐reactive antigens, a 64‐kDa band antigen, also reacted with a monoclonal antibody directed to the human heat shock protein (HSP) 60. The N‐terminal amino acid sequence of this C. rectus protein revealed a high degree of homology with corresponding regions of other HSPs belonging to the HSP60 family, indicating that the 64‐kDa antigen was a GroEL protein. The nucleotide sequence of the C. rectus GroEL protein coded for a 547 amino acid protein with a predicted size of 57.8 kDa. Comparison of the alignment of the deduced amino acid sequence of the GroEL protein of C. rectus with that of H. pylori showed a high degree of similarity throughout its length (76.8%). GroEL protein from C. rectus possessed the ability to stimulate production of IL‐6 by a confluent monolayer of human gingival epithelial cells and was cytotoxic when used at a high concentration.

Conclusions:  This study reveals an immunological relationship between H. pylori and C. rectus, and clearly indicates that one of the shared antigens is a GroEL protein possessing a biological activity that might play a role in the initiation and progression of periodontal disease.
Distribution of Bacteroides forsythus genotypes in a Japanese periodontitis population
Authors: Huang Y. , Umeda M. , Takeuchi Y. , Ishizuka M. , Yano‐Higuchi K. , Ishikawa I.
Published: December 2004

Bacteroides forsythus is an important pathogen in periodontal diseases and has been associated with advanced and refractory periodontitis. The difficulties associated with culturing this species have meant that the distribution and pathogenic mechanisms of B. forsythus remain unclear. In this study, the arbitrarily primed polymerase chain reaction (AP‐PCR) method was used to investigate the genotype distribution of B. forsythus in a Japanese periodontitis population, as well as the relationship between AP‐PCR genotypes and periodontal status. B. forsythus reference strain, ATCC 43037T and 137 clinical bacterial isolates from 64 subjects were separated into 11 distinct AP‐PCR genotypes using a single randomly‐sequenced primer, 5′‐CCGGCGGCG‐3′ (A‐05). The majority (80.9%) of B. forsythus strains examined belonged to AP‐PCR genotypes I, II, III and IV (accounting for 39.7%, 20.6%, 10.3% and 10.3%, respectively). Types I and III primarily consisted of isolates from chronic periodontitis subjects (80.8% and 85.7%, respectively), while Types II and IV consisted mainly of isolates from aggressive periodontitis subjects (85.7% and 100%, respectively). Except for three subjects who harbored two different B. forsythus genotypes in the oral cavity, all subjects only infected with one genotype intraindividually. These results demonstrate that the AP‐PCR method is useful for genotypic analysis of B. forsythus. This species showed a genetic diversity among the investigated population. A clonal nature of B. forsythus infection is suggested. Furthermore, different AP‐PCR genotypes of B. forsythus appear to be associated with different types of periodontitis.
Real‐time interaction of oral streptococci with human salivary components
Authors: Kawashima M. , Hanada N. , Hamada T. , Tagami J. , Senpuku H.
Published: December 2004

Oral streptococci are present in large numbers in dental plaque and several types interact with the enamel salivary pellicle to form a biofilm on tooth surfaces. The respective affinity of individual streptococci for salivary components has an influence on the etiologic properties of oral biofilm in the development of dental caries. We studied real‐time biospecific interactions between oral streptococci and salivary components utilizing biosensor technology to analyze surface plasmon resonance. Streptococcus sanguis and Streptococcus mutans showed significant responses for binding to salivary components, in comparison with other bacteria. Further, the association rates (4.1 × 10−11/bacterium) and dissociation rate (5.7 ± 0.9 × 10−3 Second(s)−1) were higher for S. sanguis than for S. mutans (2.4 × 10−11 and 2.9 ± 0.8 × 10−3) and Streptococcus mitis (1.3 × 10−11 and 3.5 ± 1.3 × 10−3). However, the association equilibrium constants (8.2 S/bacterium) for S. mutans was 2 times higher in than S. mitis (3.8) and slightly higher than S. sanguis (7.2). These findings may provide useful information regarding the mechanism of early biofilm formation by streptococci on the tooth surface.