bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface passivation of GaAs using a Ge interface control layer
Authors: Jishiashvili D. , Gobsch G. , Ecke G. , Gobronidze V. , Mtskeradze G. , Shiolashvili Z.
Published: June 2005

The effective surface passivation is a key to achieve useful metal–insulator–semiconductor devices on GaAs. In this work, the composition and structure of the pyrolytic GeOxNy film deposited on GaAs in the hydrazine vapour has been studied by Auger electron spectroscopy and transmission electron microscopy. The capacitance‐voltage characteristics was used to investigate the GeOxNy–GaAs interface in the frequency range of 1 kHz–1 MHz. The deposited insulator film has a layered structure and consists of a thin (∼2–4 nm) amorphous Ge interface control layer adjacent to the GaAs, followed by the outer GeOxNy film. It is found that a high quality interface is formed with the minimum interface state density of 3 × 1011 cm–2 eV–1 at midgap energies in GaAs. It is suggested that a good bond matching at the GaAs–Ge interface and coherent termination of bonds at both sides of the Ge interface control layer are the reason for perfect passivating properties of the GeOxNy film. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Defect study on deformed Fe–Si alloys by positron annihilation techniques
Authors: Agundez M. , Ruiz D. , Petegem S. Van , De Baerdemaeker J. , Chou K. W. , Segers D. , Houbaert Y.
Published: June 2005

Positron annihilation lifetime and coincidence Doppler broadening measurements have been performed on ultra low carbon steel and Fe–Si alloys with different Si contents (from 3.32 up to 11.1 wt%) in the annealed state and after a deformation of 5% thickness reduction. It was seen that above 5.6 wt% Si the nature of the defects trapping the positron changes. This coincides with the concentration for the onset of long range D03 ordering in the Fe–Si alloys changing the nature of the dislocation structure. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Two‐step method for precise calculation of core properties in molecules
Authors: Titov A. V. , Mosyagin N. S. , Petrov A. N. , Isaev T. A.
Published: May 2005

Precise calculations of core properties in heavy‐atom systems that are described by the operators heavily concentrated in atomic cores, such as hyperfine structure and P,T‐parity nonconservation effects, require accounting for relativistic effects. Unfortunately, four‐component calculation of molecules containing heavy elements is very consuming already at the stages of calculation and transformation of two‐electron integrals with a basis set of four‐component spinors. In turn, the relativistic effective core potential (RECP) calculations of valence (spectroscopic, chemical, etc.) properties of molecules are very popular, because the RECP method allows one to treat quite satisfactorily the correlation and relativistic effects for the valence electrons of a molecule and to reduce significantly the computational efforts. The valence molecular spinors are usually smoothed in atomic cores, and, as a result, direct calculation of electronic densities near heavy nuclei is impossible. In this paper, the methods of nonvariational and variational one‐center restoration of correct shapes of four‐component spinors in atomic cores after a two‐component RECP calculation of a molecule are discussed. Their efficiency is illustrated in correlation calculations of hyperfine structure and parity nonconservation effects in heavy‐atom molecules YbF, BaF, TlF, and PbO. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Foundations of the relativistic theory of many‐electron bound states
Authors: Sucher J.
Published: May 2005

Most of the existing calculations of relativistic effects in many‐electron atoms or molecules are based on the Dirac–Coulomb Hamiltonian HDC. However, because the electron–electron interaction mixes positive‐ and negative‐energy states, the operator HDC has no normalizable eigenfunctions. This fact undermines the quantum‐theoretic rationale for the Dirac–Hartree–Fock (DHF) equations and therefore that of the relativistic configuration‐interaction (RCI) and multiconfiguration Dirac–Fock (MCDF) methods. An approach to this problem based on quantum electrodynamics is reviewed. It leads to a configuration‐space Hamilton H which involves positive‐energy projection operators dependent on an external potential U; identification of U with the nuclear potential Vext corresponds to use of the Furry bound‐state interaction picture. It is shown that the RCI method can be reinterpreted as an approximation scheme for finding eigenvalues of a Hamiltonian H, with U identified as the DHF potential; the theoretical interpretation of the MCDF method needs further clarification. It is emphasized that if U differs from Vext one must consider the effects of virtual‐pair creation by the difference potential δU = Vext − U; an approximate formula for the level‐shift arising from δU is derived. Some ideas for dealing with the technical problems introduced by the projection operators are discussed and relativistic virial theorems are given. Finally, a possible scheme for adapting current MCDF methods to Hamiltonians involving projection operators is described.
Relativistic studies of atoms and ions with complex configurations
Authors: Rudzikas Z. B.
Published: May 2005

The method of the relativistic investigation of the energy spectra and the electronic transitions in the case of complex configurations, based on the theory of the irreducible tensorial operators and the genealogical coefficients, is described. The use of the quasispin and isospin technique in the relativistic approximation is discussed. Expressions are presented for electric multipole transition probabilities for general values of the gauge condition of electromagnetic field potential.
Relativistic calculation of autoionization widths of 1s2s2pjJ, 1s2s22S1/2, and 1s2pJ2pj′J levels
Authors: Safronova U. I. , Tsirekidze T. A.
Published: May 2005

The autoionization widths of levels 1s 2s 2pjJ, 1s2s2 2S1/2, and 1s2pj2pj′ J have been calculated for ions with Z = 6–30. The calculation has been carried out in intermediate coupling. The decay amplitudes have been calculated in a relativistic approximation.
Use of the S‐matrix in the relativistic treatment of resonance energy transfer
Authors: Avery John
Published: May 2005

The S‐matrix formalism is used to treat the phenomenon of resonance energy transfer (sensitized fluorescence). It is shown that for dipole‐allowed transitions and short sensitizer–acceptor separations, the relativistic treatment yields the same result as the nonrelativistic Perrin–Förster theory. For large sensitizer‐acceptor separations, long‐range coupling terms appear in the relativistic treatment. Resonance energy transfer through these long‐range coupling terms is compared with spontaneous photon emission, and direct‐interaction theories of electromagnetism are discussed. In the Appendix it is shown that the relativistic theory predicts resonance transfer of triplet excitation energy through the spin–spin coupling term in the Breit interaction.
Self‐consistent Dirac–Slater calculations for molecules and embedded clusters
Authors: Ellis D. E. , Goodman G. L.
Published: May 2005

The basis of self‐consistent local density theory used in the fully relativistic Dirac–Slater model is briefly reviewed. Moment‐polarized extensions of theory are developed to treat open‐shell systems by lifting the pair‐wise Kramers degeneracy. The discrete variational method is used to calculate one‐electron energies and charge and magnetization densities of a series of rare‐earth trihalides. The theoretical binding energies compare very well with recent gas‐phase photoelectron spectra of Berkowitz et al. The von Barth–Hedin exchange and correlation potential produces energies which are significantly better, compared to simpler exchange‐only models. Embedded molecular cluster studies on actinide compounds are reported, with particular emphasis on the AcO2 dioxides. Single‐particle energy densities of states (DOS) and magnetization DOS are presented, along with an analysis of effective atomic configurations in the solid. Trends in these quantities with actinide atomic number are noted. In contrast to the semicore nature of rare‐earth 4f electrons, the actinide 5f levels are seen to be active participants in bonding interactions.
Spin‐orbit excitation in the system I + I2: Relativistically parameterized extended‐Hückel calculations
Authors: Viste A. , Pyykkö P.
Published: May 2005

Relativistically parameterized extended‐Hückel (REX) calculations concerning species and exchange reactions in the system I or I* + I2 are reported, where I = 2P3/2 and I* = 2P1/2. From their experimental data for related halogen systems X + YZ XY + Z, E. B. Gordon, A. I. Nadkhin, S. A. Sotnichenko, and I. A. Boriev [(Chem. Phys. Lett. 86, 209 (1982)] have proposed a conservation rule for the spin‐orbit state (X* → Z*, X → Z). The results of REX calculations, double‐group symmetry analysis, and schematic state correlation diagrams reported here are consistent with the proposed conservation rule. Two of the transition states are linear and the third nearly so, but no Γ1/2–Γ3/2 crossings leading to spin‐orbit conversion are found.
Relativistic band structure calculations
Authors: Christensen N. Egede
Published: May 2005

The inclusion of relativistic effects in band theory is discussed. Examples showing how these affect optical properties, Fermi surface properties, and cohesive properties are shown. With respect to the latter, it is pointed out that the mass–velocity and Darwin shifts are most important, whereas the SO coupling can be omitted since it does not shift the bands (quenching of angular momentum). The band theoretical aspects are presented in the terminology of the LMTO‐ASA method which offers a physical transparent picture of the formation of bands. The volume and energy dependences of the spin‐orbit splittings are explained in this picture. As examples are considered calculations for W, Xe, Au, and the copper halides.
Interaction of O2, CO and CO2 with Co films
Authors: Frerichs M. , Schweiger F. X. , Voigts F. , Rudenkiy S. , Maus‐Friedrichs W. , Kempter V.
Published: May 2005

Metastable impact electron spectroscopy (MIES), ultraviolet photoelectron spectroscopy (UPS(HeI)) and x‐ray photoelectron spectroscopy (XPS) were applied to study the interaction of O2, CO and CO2 with Co films at room temperature. The films were produced on Si(100) surfaces under the in situ control of MIES, UPS and scanning tunnelling microscopy (STM). For O2, dissociative adsorption takes place initially and then incorporation of oxygen starts at exposures of ∼5 L. Comparison of the MIES and UPS spectra with those published for CoO shows that near‐stoichiometric CoO films can be obtained by co‐deposition of Co and O2. The CO is adsorbed molecularly up to a maximum coverage of ∼0.6 monolayer, with the C‐end pointing towards the surface. The CO2 adsorption is dissociative, resulting in the formation of Co–CO bonds at the surface. The resulting oxygen atoms are mostly incorporated into the Co layer. For all studied molecules the interaction with Co is similar to that with Ni. Copyright © 2005 John Wiley & Sons, Ltd.
Scenario‐based decision making for architectural variability in product families
Authors: America Pierre , Hammer Dieter , Ionita Mugurel T. , Obbink Henk , Rommes Eelco
Published: May 2005

In this article, we present a systematic approach towards decision making for variability in product families in the context of uncertainty. Our approach consists of the following ingredients: A suitable set of architectural views that bridge the gap between customer needs and available technology, a multiview variation modeling technique, the selection of several scenarios of different kinds, and a quantitative analysis of quality aspects for these scenarios. Copyright © 2005 John Wiley & Sons, Ltd.
Experiences with conducting project postmortems: reports versus stories
Authors: Desouza Kevin C. , Dingsøyr Torgeir , Awazu Yukika
Published: May 2005

The most popular unit of work in organizations is a project. Managing knowledge in and about projects is salient for successful project management. In this article, we will discuss how postmortems can be used to capture tacit experiences in projects. Conducting a postmortem, either after a milestone or at the end of a project, is salient in order to gauge what has been learnt, what were the main issues faced, and what can be used to improve the processes of work in the future. The conducting of postmortems aids in articulation of tacit experiences into explicit forms. This enables for experiences to be better re‐used in the future. Re‐using of postmortem findings depends heavily on the nature of the postmortem outcome. We will compare two kinds of postmortem outcomes—traditional reports and stories. Both types have their pros and cons, and management must choose the right kind of postmortem report to calibrate, depending on the project and learning outcomes. The article will also highlight lessons learnt from conducting postmortem reviews in several software organizations. Copyright © 2005 John Wiley & Sons, Ltd.
Über Organo‐Phosphore mit anorganischem Grundmaterial. II. (Sauerstoffempfindliche Borsäure–Phosphore)
Authors: Chomse Heinz
Published: May 2005

1. Borsäure‐Phosphore, die in ihrer Lumineszenzfähigkeit durch die Anwesenheit von Sauerstoff beeinflußt werden, waren bisher nicht bekannt. Es wird die Darstellung von solchen Borsäure‐Phosphoren beschrieben, die in ihrem Verhalten gegenüber Sauerstoff den von H. KAUTSKY gefundenen phosphoreszenzfähigen Farbstoffadsorbaten weitgehend entsprechen und somit die Vorstellungen über die dem Lumineszenzvermögen zugrundeliegenden Mechanismen auf die Borsäure‐Phosphore zu übertragen gestatten.
A Nurse-Led Rapid Access Chest Pain Clinic—Experience from the First 3 Years
Authors: Pottle Alison
Published: June 2005

Background: The clinical presentation of chest pain is a major problem for primary health care professionals. Rapid access chest pain clinics (RACPC) enable quick assessment, investigation and formation of a treatment plan for such patients without a waiting list. There has been a chest pain clinic in operation at Harefield Hospital since 1988. Until 2001, the cardiology registrars were responsible for the clinic. Beginning in January 2001, the management of the clinic was taken over by the Cardiology Nurse Consultant. This paper will describe the organisation and outcomes of the first 3 years of this nurse-run RACPC.

Process: Patients are seen within 2 weeks of referral in line with the National Service Framework for Coronary Heart Disease [Department of Health. National service framework for coronary heart disease. Dept of Health; 2000. London.]. An electrocardiogram (ECG) is recorded on arrival in the clinic and the Nurse Consultant then examines the patients and decides if further investigation is required.

Analysis of Results: Four hundred and fifty-four patients were seen in the clinic from January 2001–December 2003. Three hundred and twenty-four patients (71.4%) underwent exercise testing of which 54 (16.7%) had a positive result. One hundred and thirteen patients (24.9%) were referred for angiography. Of these, 75 (66.4%) had coronary heart disease. Thirty-three patients (29.2%) have undergone percutaneous coronary intervention (PCI) and 19 (16.8%) have required coronary artery bypass grafting (CABG). Twenty-three patients (20.4%) are being treated medically. Satisfaction with the service offered by the clinic was high, evidenced by the results of questionnaires sent to patients.

Conclusion: This paper demonstrates that nurses can successfully run RACPCs without an increased risk of incorrect diagnosis. These clinics offer patients timely access to assessment of their chest pain and facilitate early diagnosis of cardiac disease. They are also well accepted by the patients attending the clinic.
Patient Experiences Following Cardiothoracic Surgery: An Interview Study
Authors: Gardner Genevieve , Elliott Doug , Gill Jaswin , Griffin Melanie , Crawford Matthew
Published: June 2005

Background: Numerous studies have investigated patient outcomes of cardiac surgery, including some examining health-related quality of life. While these studies have provided some insight into patients' physical function, social abilities and perceived quality of life, studies examining the experiences of individuals recovering from cardiac surgery have received only limited investigation.

Aims: This paper presents a thematic analysis of interviews conducted with patients recovering from cardiothoracic surgery, about their memories and experiences of hospital and recovery post-hospital discharge.

Methods: Using an exploratory qualitative approach, eight participants were interviewed 6 months following their surgery. Transcripts of interviews were examined using a content analysis approach, with open coding of text and categorising of similar concepts into themes.

Findings: Participants reported varying degrees of pain and physical dysfunction during their recovery from surgery and some had still not returned to optimal function. Seven themes emerged from the data: impressions of ICU; comfort/discomfort; being sick/getting better; companionship/isolation; hope/hopelessness; acceptance/apprehension; and life changes. A number of the themes were constructed as a continuum, with participants often demonstrating a range of views or experiences. Many had little or no memory of their stay in the intensive care unit, although others had vivid recollections. Their impressions of hospital were mostly positive, although many experienced fear, apprehension, and mood disturbances at some time during their recovery. Most participants recalled being sick, reaching a turning point, and then getting better. Many participants reported a change in life view since their recovery from surgery.

Conclusions: Attention to specific areas of patient orientation, education and support was identified to facilitate realistic expectations of recovery. In addition, some form of systematic follow-up that focuses on patient recovery in terms of both physical and psychological function is important.
Effects of a Problem-Based Learning Rehabilitation Programme on Quality of Life in Patients with Coronary Artery Disease
Authors: Tingström Pia R. , Kamwendo Kitty , Bergdahl Björn
Published: June 2005

Background: The aim of cardiac rehabilitation (CR) is not only physical improvement but also increased quality of life (QoL). A CR programme based upon problem based learning (PBL) philosophy was developed, to achieve and apply new knowledge related to coronary artery disease (CAD). The aim of this paper was to evaluate the impact of the PBL programme on QoL.

Methods: 207 consecutive patients < 70 years of age with a recent event of CAD were randomised to a PBL group ( n = 104) or a control group ( n = 103). In addition to standard treatment, the PBL patients participated in 13 group sessions during 1 year, where individual learning needs and behavioural changes were focused upon. QoL was measured by the Ladder of Life, Self-Rated Health (SRH), SF 36, and Cardiac Health Profile (CHP).

Results: Significant differences between the groups, favouring the PBL patients, were found by global instruments: more optimistic expectations of the future QoL and a better general condition. No differences were found by SRH, SF 36 or subscales of CHP, but QoL increased in both groups during the year.

Conclusions: The main outcome was that QoL improved in both groups with some effects favouring the PBL programme.
Induced resistance to the antimicrobial peptide lactoferricin B in Staphylococcus aureus
Authors: Samuelsen Ørjan , Haukland Hanne H. , Jenssen Håvard , Krämer Manuela , Sandvik Kjersti , Ulvatne Hilde , Vorland Lars H.
Published: June 2005

This study was designed to investigate inducible intrinsic resistance against lactoferricin B in Staphylococcus aureus. Serial passage of seven S. aureus strains in medium with increasing concentrations of peptide resulted in an induced resistance at various levels in all strains. The induced resistance was unstable and decreased relatively rapidly during passages in peptide free medium but the minimum inhibitory concentration remained elevated after thirty passages. Cross‐resistance to penicillin G and low‐level cross‐resistance to the antimicrobial peptides indolicidin and Ala3,13,18‐magainin was observed. No cross‐resistance was observed to the human cathelicidin LL‐37. In conclusion, this study shows that S. aureus has intrinsic resistance mechanisms against antimicrobial peptides that can be induced upon exposure, and that this may confer low‐level cross‐resistance to other antimicrobial peptides.
Characterization and comparative analysis of Arabidopsis phosphatidylinositol phosphate 5‐kinase 10 reveals differences in Arabidopsis and human phosphatidylinositol phosphate kinases
Authors: Perera Imara Y. , Davis Amanda J. , Galanopoulou Dia , Im Yang Ju , Boss Wendy F.
Published: June 2005

Arabidopsis phosphatidylinositol phosphate (PtdInsP) kinase 10 (AtPIPK10; At4g01190) is shown to be a functional enzyme of the subfamily A, type I AtPtdInsP kinases. It is biochemically distinct from AtPIPK1 (At1g21980), the only other previously characterized AtPtdInsP kinase which is of the B subfamily. AtPIPK10 has the same K
m, but a 10‐fold lower V
max than AtPIPK1 and it is insensitive to phosphatidic acid. AtPIPK10 transcript is most abundant in inflorescence stalks and flowers, whereas AtPIPK1 transcript is present in all tissues. Comparative analysis of recombinant AtPIPK10 and AtPIPK1 with recombinant HsPIPKIα reveals that the Arabidopsis enzymes have roughly 200‐ and 20‐fold lower V
max/K
m, respectively. These data reveal one explanation for the longstanding mystery of the relatively low phosphatidylinositol‐(4,5)‐bisphosphate:phosphatidylinositol‐4‐phosphate ratio in terrestrial plants.
Genetic identification of hake and megrim eggs in formaldehyde-fixed plankton samples
Authors: Perez Juliana , Álvarez Paula , Martinez Jose L. , Garcia-Vazquez Eva
Published: June 2005

Spawning of European hake (Merluccius merluccius) and megrim (Lepidorhombus whiffiagonis and L. boscii) overlap in time and space. Their eggs are morphologically similar, so genetic identification is needed for purposes of stock assessment based on plankton surveys. Amplification fragment sizes of a partial sequence within the 16S rRNA genes are different for Merluccius merluccius, Lepidorhombus boscii, and L. whiffiagonis. Species-specificity of the pattern was confirmed after analysing adult individuals from all distribution areas of the three species. After Chelex-based DNA extraction and PCR amplification, fragment sizes at this gene were successfully determined from 85% formaldehyde-fixed eggs and larvae recovered from plankton samples. Species-specificity was resolved using an ABI genetic analyser. The results were 100% reproducible. This methodology for genetic identification of hake and megrim eggs can be very useful for stock assessment of these three commercially important fish species.
Early versus delayed oral feeding after cesarean delivery
Authors: Kovavisarach E. , Atthakorn M.
Published: June 2005

Objective: To compare possible adverse gastrointestinal effects after cesarean section in women who took their first meal early compared with those whose first meal was delayed (8 h versus 24 h). Methods: A total of 151 pregnant women with indications for cesarean section but no medical, obstetric, or surgical complications were randomized to two groups, the early oral feeding group (75 women) and the delayed oral feeding group (76 women), at Rajavithi Hospital from November 1, 2002 to June 30, 2003. Results: There were no significant demographic differences between the two groups but there were significant differences in amount of blood loss, time to first bowel sound, and duration of intravenous fluid infusion and Foley catheter use. All these were less in the early feeding group, but there were no significant differences in postoperative gastrointestinal complications. Conclusion: Early oral feeding after cesarean delivery (8 h) caused no significant adverse gastrointestinal effects compared with delayed feeding (24 h).
CAUSES OF NEONATAL MORTALITY IN SPAIN (1975–98): INFLUENCE OF SEX, RURAL–URBAN RESIDENCE AND AGE AT DEATH
Authors: ALONSO VERÓNICA , FUSTER VICENTE , LUNA FRANCISCO
Published: June 2005

Neonatal mortality during the first week of life, corresponding to the years 1975–1998, was studied in Spain. The first week of life is the time in which the highest number of deaths occur. The temporal decrease of the neonatal mortality rate (NMR) was modelled according to log10(NMR+1)= 2·784−0·023 per year. This decline cannot be explained by an increase in the mean birth weight (MBW=23440·835−10·107 g per year). From the most frequent of the causes of death to the least were: congenital anomalies, preterm born or low birth weight, respiratory problems, pregnancy difficulties, hypoxaemia/asphyxia, delivery difficulties and infectious diseases. This sequence changed when the specific age at death was considered. The NMR descended evenly for both sexes for the causes indicated above, except for preterm born or low birth weight, in which the male mortality decrease was greater since its rate was more elevated at the beginning of the period studied. For all the causes listed, NMR was more elevated both in urban areas and for males. Early neonatal mortality (first 24 hours) was higher for pregnancy difficulties, preterm born or low birth weight, congenital anomalies and hypoxaemia/asphyxia.
THE EFFECT OF FERTILITY LIMITATION ON INTERGENERATIONAL SOCIAL MOBILITY: THE QUALITY–QUANTITY TRADE-OFF DURING THE DEMOGRAPHIC TRANSITION
Authors: VAN BAVEL JAN
Published: June 2005

The hypothesis that family size limitation by parents enhances the upward mobility chances of their children in (post)industrial populations has a long-standing record in many disciplines, including sociology and economics, as well as evolutionary anthropology and social biology. Yet the empirical record supporting or contradicting the theory is surprisingly limited. The aim of this contribution is to develop a test of the effect of family size limitation on children’s intergenerational mobility. This test is applied to an urban population in Belgium that was in the process of experiencing its demographic transition, including the decline of fertility, at the end of the 19th century. The results indicate that the effect of family size was strong, even after controlling for parental social status as well as birth order. Surprisingly, the effects of birth order and family size appear to be largely independent.
The influence of gibbon primary seed shadows on post-dispersal seed fate in a lowland dipterocarp forest in Central Borneo
Authors: McConkey Kim R.
Published: May 2005

The natural seed shadow created by gibbons (Hylobates mulleri×agilis) in Central Kalimantan, Indonesia, was monitored over 11 mo to discern the role of gibbons and post-dispersal events in the spatial pattern of seed germination. Variability in the content and distribution of 183 scats was used to determine which, if any, scat characteristics influenced seed fate. Nine scat characters were evaluated: (1) seed number; (2) number of seed species per scat; (3) scat weight; (4) seed load; (5) rainfall; (6) scat density; (7) distance to nearest fruiting tree; (8) ripe fig abundance; (9) non-fig fruit abundance. More than 99% of monitored seeds were killed, removed, or had germinated during the monitoring period. Vertebrates killed or removed most seeds (86%) and the probability of them moving seeds was highly dependent on non-fig fruit abundance at the time of deposition; factors (2), (6) and (7) also influenced seed removal/predation by vertebrates, depending on whether seeds were deposited in peak or non-peak times of consumption. Insect predation (2% of seeds) occurred mainly in scats that were deposited in months of high ripe fig abundance, while the actual chance of a seed germinating (11% of seeds) was influenced by non-fig fruit abundance at time of deposition and number of species in the original scat. The gibbon-generated seed shadow was profoundly altered by post-dispersal events and variation in the characteristics of the shadow had little lasting impact on the probability of seeds germinating.
Pair-wise competition-trials amongst seedlings of ten dipterocarp species; the role of initial height, growth rate and leaf attributes
Authors: Tanner E. V. J. , Teo V. K. , Coomes D. A. , Midgley J. J.
Published: May 2005

To investigate whether seedlings of ten dipterocarp species differed significantly in terms of growth and mortality or whether species were not significantly different and could be considered ecologically similar, seedlings were grown, two per pot, in two experiments: (1) where the two seedlings were of equal height (30 cm); and (2) where one seedling was 10 cm shorter than the other. Seedlings were grown in a shade house with 15% above-canopy light in a 50:50 forest soil–sand mixture and were watered frequently; pots were placed so that seedling density was 130 seedlings m−2 of ground. In the first experiment there were 45 pairwise combinations of species when seedlings were 30 cm tall (AB, AC, AD,…. BC, BD…IJ; where A, B, C…J signify different species); each combination was replicated 10 times so there were 450 pots with 900 seedlings. In the second experiment there were 100 pairwise combinations of species and size e.g. Aa (30 cm A with 20 cm a), Ab (30 cm A with 20 cm b), each combination was replicated 10 times hence there were 1000 pots with 2000 seedlings. After 22 mo 79% of the initial 2900 seedlings survived; on average they had grown 42 cm (i.e. to 72 cm tall from their initial 30 cm). The most frequent outcome of competition-trials between different sized individuals (784 of 1000 trials) was that the initially taller seedling of each pair ‘won’ (it was the taller or surviving seedling). When 900 of these trials (setting aside, Aa, Bb, Cc etc.) were analysed as 45 comparisons between species with different sized individuals (Ab and aB are one interspecific comparison for these purposes), initial height determined the outcome in 23 cases (even in some competitions between light hardwood species and heavy hardwood species); in 6 cases a species (mostly light hardwoods) behaved as a ‘dominant’ – they usually won even if they were smaller initially. We found few significant differences between species in: initial seedling heights; leaf nitrogen concentrations; and specific leaf areas when they were grown in similar conditions, and these attributes were not correlated with growth rates. The similarity of seedlings of different species meant that often a height difference of just 10 cm was enough to determine the outcome of a pairwise competition-trial in high seedling densities and light equivalent to that in forest gaps.
Scale-dependent habitat selection in three didelphid marsupials using the spool-and-line technique in the Atlantic forest of Brazil
Authors: Moura Maíra C. , Caparelli Alice C. , Freitas Simone R. , Vieira Marcus V.
Published: May 2005

Habitat selection can be detected at different scales. For small mammals, habitat studies normally evaluate micro- or meso-habitat selection, but rarely are multiple scales analysed simultaneously. These studies use quantitative data of structural characteristics around the trap stations to evaluate selection. We test an alternative method to evaluate habitat selection in three didelphid marsupials (Didelphis aurita, Philander frenatus and Metachirus nudicaudatus), using a spool-and-line device, and measure habitat selection at two spatial scales. Habitat was characterized by seven habitat variables measured at ten points of direction change along the path traversed by each individual, and at 25 trap stations distributed in a 1-ha area. Micro-habitat selection was estimated at each point by comparing habitat measures between the direction selected against other directions. Meso-habitat selection was estimated by comparing habitat measurements on the whole path of an individual against habitat measures on the 25 trap stations. Patterns of selection for each species could only be detected at the meso-habitat scale, although a few individuals in each species were selective at the micro-habitat scale. Studies of habitat selection need to address the scale of study quantitatively, if possible comparing two or more scales to determine the scale of selection.
Loci: a rule-based framework for parallel multi-disciplinary simulation synthesis
Authors: LUKE EDWARD A. , GEORGE THOMAS
Published: June 2005

We present a rule-based framework for the development of scalable parallel high performance simulations for a broad class of scientific applications (with particular emphasis on continuum mechanics). We take a pragmatic approach to our programming abstractions by implementing structures that are used frequently and have common high performance implementations on distributed memory architectures. The resulting framework borrows heavily from rule-based systems for relational database models, however limiting the scope to those parts that have obvious high performance implementation. Using our approach, we demonstrate predictable performance behavior and efficient utilization of large scale distributed memory architectures on problems of significant complexity involving multiple disciplines.
Parallel functional programming in Eden
Authors: LOOGEN RITA , ORTEGA-MALLÉN YOLANDA , PEÑA-MARÍ RICARDO
Published: June 2005

Eden extends the non-strict functional language Haskell with constructs to control parallel evaluation of processes. Although processes are defined explicitly, communication and synchronisation issues are handled in a way transparent to the programmer. In order to offer effective support for parallel evaluation, Eden's coordination constructs override the inherently sequential demand-driven (lazy) evaluation strategy of its computation language Haskell. Eden is a general-purpose parallel functional language suitable for developing sophisticated skeletons – which simplify parallel programming immensely – as well as for exploiting more irregular parallelism that cannot easily be captured by a predefined skeleton. The paper gives a comprehensive description of Eden, its semantics, its skeleton-based programming methodology – which is applied in three case studies – its implementation and performance. Furthermore it points at many additional results that have been achieved in the context of the Eden project.
Response of primary production and calcification to changes of pCO2 during experimental blooms of the coccolithophorid Emiliania huxleyi
Authors: Delille Bruno , Harlay Jérôme , Zondervan Ingrid , Jacquet Stephan , Chou Lei , Wollast Roland , Bellerby Richard G. J. , Frankignoulle Michel , Borges Alberto Vieira , Riebesell Ulf , Gattuso Jean‐Pierre
Published: June 2005

Primary production and calcification in response to different partial pressures of CO2 (PCO2) (“glacial,” “present,” and “year 2100” atmospheric CO2 concentrations) were investigated during a mesocosm bloom dominated by the coccolithophorid Emiliania huxleyi. The day‐to‐day dynamics of net community production (NCP) and net community calcification (NCC) were assessed during the bloom development and decline by monitoring dissolved inorganic carbon (DIC) and total alkalinity (TA), together with oxygen production and 14C incorporation. When comparing year 2100 with glacial PCO2 conditions we observed: (1) no conspicuous change of net community productivity (NCPy); (2) a delay in the onset of calcification by 24 to 48 hours, reducing the duration of the calcifying phase in the course of the bloom; (3) a 40% decrease of NCC; and (4) enhanced loss of organic carbon from the water column. These results suggest a shift in the ratio of organic carbon to calcium carbonate production and vertical flux with rising atmospheric PCO2.
Upwelling of Arctic pycnocline associated with shear motion of sea ice
Authors: McPhee M. G. , Kwok R. , Robins R. , Coon M.
Published: May 2005

High‐resolution radar imagery shows that the dynamic response of winter sea ice to gradients in large‐scale surface wind stress is often localized along quasi‐linear fractures hundreds of kilometers long. Relative shearing motion across these narrow fractures can exceed 10 cm s−1. In one event recorded during the drift of the SHEBA ice camp, we observed an intense zone of pycnocline upwelling (∼14 m) associated with significant shear motion near the camp, while upward turbulent heat flux in the ocean boundary layer reached nearly 400 W m−2, an order of magnitude greater than at any other time during the year‐long drift. We attribute the upwelling to Ekman pumping associated with concentrated ice shear. Over the entire Arctic Ocean sea ice cover, this process could be responsible for significant heat exchange between the cold surface layer and warmer subsurface water at the ubiquitous fractures resulting from large‐scale atmosphere‐ice interactions.
Magnetic field fluctuations during substorm‐associated dipolarizations in the nightside plasma sheet around X = −10 RE
Authors: Shiokawa K. , Shinohara I. , Mukai T. , Hayakawa H. , Cheng C. Z.
Published: May 2005

Using high‐time‐resolution data for the magnetic field (1/16 s), plasma moment (12 s), and electric field (3 s) obtained by Geotail, we have investigated various characteristics of magnetic field fluctuations for 21 events of substorm‐associated near‐Earth dipolarization at XGSM = −8 ∼ −11 RE and ∣YGSM∣ < 5 RE. The dipolarizations were always accompanied by fluctuations of the magnetic field. The amplitude of the fluctuations tends to be larger for smaller ambient magnetic field. For several events we found that magnetic field elevation angles show rapid decrease prior to the rapid increase (features like explosive growth phase). Compressional fluctuations of magnetic field intensity B show characteristic spikes of a sudden decrease and increase with a timescale of seconds. For quite a few cases the fluctuations are accompanied by enhancements of earthward plasma velocity. The spectral shape of the B fluctuations had a steeper slope (f−2.7) at higher frequency range at 1.0–0.2 Hz than at 0.01–0.2 Hz (f−2.0) for the events closer to the cross‐tail current sheet (smaller ambient‐B region). We found that the steeper slope extends to lower frequency range below 0.2 Hz for the events away from the current sheet (larger ambient‐B region). This fact may suggest transition from three‐dimensional to two‐dimensional turbulence from smaller B to larger B region. We also investigated correlation of fluctuations in plasma velocity and magnetic field for waves with periods around 60 s. The correlations were rather weak, suggesting that non‐MHD plasma processes are going on. For these waves, the magnetic and plasma pressure variations were clearly antiphase.
On the source of Pc1‐2 waves in the plasma mantle
Authors: Engebretson M. J. , Onsager T. G. , Rowland D. E. , Denton R. E. , Posch J. L. , Russell C. T. , Chi P. J. , Arnoldy R. L. , Anderson B. J. , Fukunishi H.
Published: June 2005

Several ground‐based observational studies have reported unstructured Pc1‐2 waves near and poleward of the dayside cusp. Dyrud et al. (1997) were the first to suggest that these waves originated in the high‐altitude plasma mantle. We report here on simultaneous field and particle observations from the Polar satellite and from ground magnetometer data that confirm the presence of these “mantle” waves and characterize the ion distributions associated with them. Unstructured Pc1‐2 waves were found to occur during 45% of the available passes of Polar across the mantle during the interval March–May 2000, during which time the orbit of Polar was near local noon as it crossed these latitudes. Poynting vector calculations using Polar electric and magnetic field data show a mixture of upward and downward energy flux in the cusp but consistently downward flux when mantle waves are observed. This is consistent with earlier observations that ground‐based magnetometers can detect such mantle waves but not the more intense wave activity observed by spacecraft in the middle‐ and low‐altitude cusp. In situ particle observations from the Hydra instrument appear to confirm the generation mechanism suggested by Dyrud et al. that cusp particles mirroring at low altitudes and then traveling outward in the plasma mantle poleward of the cusp are the source of the free energy for these waves. Quantitative estimates of ion cyclotron instability of the observed ion distributions suggest they are stable at the ≤9 RE altitudes traversed by Polar but may be reasonably inferred to be unstable in the exterior mantle, a location consistent with their observed frequency.
Velocity oscillations in the outer heliosphere: A signature of pickup ion temperature variability?
Authors: Zank G. P. , Ao X. , Richardson J. D.
Published: May 2005

Unusual long wavelength (0.5–1 AU), low‐frequency (∼3 × 10−5 s−1) velocity oscillations have been observed by Voyager 2 at 48 AU in the outer heliosphere (Paularena et al., 1996). The velocity oscillations appear to be superimposed on weak linear velocity gradients that are typically increasing. To date, no explanation has been advanced for the origin of either the flow gradients or the oscillations. Here we show that pickup ions can excite low‐frequency fluctuations and drive the flow field linearly. The model is compared directly to velocity oscillations observed by the Voyager 2 PLS instrument between 40 and 55 AU over the 6‐year period 1993–1998.
Stability of the inner source pickup ions over the solar cycle
Authors: Allegrini F. , Schwadron N. A. , McComas D. J. , Gloeckler G. , Geiss J.
Published: May 2005

Inner source pickup ions (PUIs) were discovered and are observed by Ulysses. They are thought to be generated by solar wind interaction with dust grains near the Sun. From previous work, four constraints were derived on inner source PUIs from observations near solar minimum: (1) the composition resembles the solar wind; (2) the distribution functions show strong adiabatic cooling, consistent with a source peaked near 10–30 RS; (3) the production rates of inner source C+ and O+ are about 2 × 106 g/s each; (4) the individual inner source counts are randomly distributed in time. We compare inner source observations over three distinct 2‐month periods in 1994, 1995, and 2001, when Ulysses was at high latitudes and about 2 AU from the Sun. Our observations not only substantiate the four constraints above but, in addition, reveal that the inner source appears stable over at least half a solar cycle and the inner source PUI flux is correlated with solar wind flux. A number of scenarios have been proposed to explain the origin of the inner source PUI. None of the proposed inner sources are consistent with our five observational constraints, suggesting that we do not yet understand the true source of these pickup ions.
Initial localization and kinematic characteristics of the structural components of a coronal mass ejection
Authors: Uralov A. M. , Grechnev V. V. , Hudson H. S.
Published: May 2005

The leading component of a coronal mass ejection (CME), its observed frontal structure (FS), has been detected close to the solar surface in a few near‐the‐limb events only. Thus far, no manifestations of such a frontal structure have been reported in reasonable proximity to a preeruptive filament located away from the solar limb. Thus the identification of the FS with preevent coronal structures remains unclear. We propose a method to estimate the parameters of the initial volume of a CME, using comparative measurements of the spatial locations of the erupting filament and FS with a self‐similar solution of the magnetohydrodynamic equations describing the expansion of the CME. We develop this method by analyzing observations of a large eruptive filament on the solar disk on 4 September 2000, using data acquired with the Solar Heliospheric Observatory (SOHO), Large‐Angle Spectroscopic Coronagraph (LASCO), and EUV Imaging Telescope (EIT) instruments and the Siberian Solar Radio Telescope. We show that if a magnetic structure corresponding to the FS prior to the filament eruption does exist, then it is localized at a relatively low height (here, about 100–150 Mm above the filament). At the initial stage of the motion, the shape of the hot FS approximately reproduces the configuration of the cool eruptive filament. In addition, we conclude that the coronal dimming observed in this event could be also due to CME‐caused suppression of the heating and/or mass supply of the dimmed structures rather than due to their opening only. We also obtain in a simple way an exact self‐similar solution of MHD equations in a form suitable for analyses of experimental data.
Dynamical controls on sub–global climate model grid‐scale cloud variability for Atmospheric Radiation Measurement Program (ARM) case 4
Authors: Weaver Christopher P. , Norris Joel R. , Gordon Neil D. , Klein Stephen A.
Published: June 2005

Global climate models (GCMs) produce large errors in cloudiness and cloud radiative forcing when simulating midlatitude, synoptic‐scale cloud systems. This is because they do not represent the subgrid‐scale processes in these systems that create subgrid variability in cloud optical thickness and cloud top pressure. Improving GCM performance will require a better understanding of these controls on subgrid cloud variability. To begin addressing this issue, this paper uses a mesoscale model, the Regional Atmospheric Modeling System (RAMS), to simulate two case study synoptic storms with much higher resolution than is possible in a GCM. These storms were observed during the Atmospheric Radiation Measurement (ARM) Program's March 2000 Intensive Observing Period (IOP) in the U.S. southern Great Plains (SGP), otherwise knows as ARM case 4. We find that RAMS is able to capture the observed storm morphology, lifecycle, and vertical structure of the atmospheric dynamic and thermodynamic variables. RAMS is also able to capture the observed fine‐scale vertical structure and temporal variation of the cloud field. Given this agreement with observations, we then characterize the model‐simulated variability in cloudiness and other variables such as vertical velocity. In both storms, there is a high degree of spatial and temporal variability in the vertical motion field across multiple scales. The variability in above‐boundary layer cloudiness is closely linked to this dynamical variability. This suggests that a parameterization for subgrid cloud water based on subgrid vertical velocity could be used to improve GCM simulations of midlatitude clouds.