bluuebunny/crossref_metadata_2025 huggingface dataset:
Stability, spectroscopic constants, and dissociation of CO2+: A theoretical study
Authors: Mondal Bhaskar , Bera Narayan C. , Das Abhijit K.
Published: September 2008

Stability, spectroscopic constants, and dissociation of CO2+ have been studied in detail using ab initio MP2, CCSD and CCSD(T) methods, and density functional B3LYP method. The stability and the ambiguity between the ground and metastable state of the molecular dication have been discussed. The spectroscopic constants of the molecular dication have been compared with the experimental and theoretical values wherever available. Various charge symmetric and charge asymmetric dissociation pathways of CO2+ have been investigated. After dissociation, the fragmented atoms and ions are considered to be either in their ground or in their metastable state. Interesting results have been obtained for the charge symmetric and charge asymmetric dissociation of the diatomic dication. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Chiral discrimination in hydrogen‐bonded complexes of 2‐methylol oxirane with hydrogen peroxide
Authors: Zhang Guiqiu , Yin Aixia , Chen Dezhan
Published: September 2008

A systematic quantum chemical study reveals the effects of chirality on the intermolecular interactions between two chiral molecules bound by hydrogen bonds. The methods used are second‐order Møller–Plesset perturbation theory (MP2) with the 6‐311++g(d,p) basis set. Complexes via the OH···O hydrogen bond formed between the chiral 2‐methylol oxirane (S) and chiral HOOH (P and M) molecules have been investigated, which lead to four diastereomeric complexes. The nomenclature of the complexes used in this article is enantiomeric configuration sign corresponding to English letters. Such as: sm, sp. The relative positions of the methylol group and the hydrogen peroxide are designated as syn (same side) and anti (opposite side). The largest chirodiastaltic energy was ΔEchir = −1.329 kcal mol−1 [9% of the counterpoise correct average binding energy De(corr)] between the sm‐syn and sp‐anti in favor of sm‐syn. The largest diastereofacial energy was −1.428 kcal mol−1 between sm‐syn and sm‐anti in favor of sm‐syn. To take into account solvents effect, the polarizable continuum model (PCM) method has been used to evaluate the chirodiastaltic energies, and diastereofacial energies of the 2‐methylol oxirane···HOOH complexes. The chiral 2,3‐dimethylol oxirane (S, S) is C2 symmetry which offers two identical faces. Hence, the chirodiastaltic energy is identical to the diastereomeric energy, and is ΔEchir = 0.563 kcal mol−1 or 5.3% of the De(corr) in favor of s,s‐p. The optimized structures, interaction energies, and chirodiastaltic energies for various isomers were estimated. The harmonic frequencies, IR intensities, rotational constants, and dipole moments were also reported. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
The communication of meaning in social systems
Authors: Leydesdorff Loet , Franse Sander
Published: September 2008

The sociological domain is different from the psychological one insofar as meaning can be communicated at the supra‐individual level. The computation of anticipatory systems enables us to distinguish between these domains in terms of weakly and strongly anticipatory systems with a structural coupling between them. Anticipatory systems have been defined as systems which entertain models of themselves. The model provides meaning to the modelled system from the perspective of hindsight, that is, by advancing along the time axis towards possible future states. Strongly anticipatory systems construct their own future states. The dynamics of weak and strong anticipations can be simulated as incursion and hyper‐incursion, respectively. Hyper‐incursion generates ‘horizons of meaning’ among which choices have to be made by incursive agency. Copyright © 2008 John Wiley & Sons, Ltd.
Modern management of renal cancer
Authors: Swallow Tom , Anderson Chris
Published: September 2008

Although the prognosis for patients with metastatic kidney cancer is poor, those presenting with localised disease are potentially curable with nephrectomy alone. The authors explain how newer, targeted therapeutic agents show promise of extending survival, and outline recent advances in surgical options and the development of more precise prognostic indicators of disease progression and survival. Copyright © 2008 Wiley Interface Ltd
Modern management of postmenopausal bleeding
Authors: Munot Sarika , Lane Geoffrey
Published: September 2008

Postmenopausal bleeding is any unscheduled vaginal bleeding that occurs after 12 months of amenorrhoea in a woman of postmenopausal age. Although a benign cause is likely, bleeding is the most common presenting symptom of endometrial cancer and should always be regarded with suspicion and investigated promptly. Copyright © 2008 Wiley Interface Ltd
Routing with hexagonal virtual coordinates in wireless sensor networks
Authors: Sheu Jang‐Ping , Hsieh Kun‐Ying , Ding Ming‐Lung
Published: September 2008

Using geographic routing, like GPSR, is efficient for ad hoc and wireless sensor networks, but it requires that nodes be aware of their physical positions. However, if there are holes in the network, routing across them using GPSR will lead to a lot of overloaded nodes on their boundaries. In this paper, we propose a distributed protocol, named hexagonal virtual coordinate (HVC), for constructing a virtual coordinate system. After the HVC is constructed, the nodes in the network will be aware of the relative coordinates among the landmarks through the HVC chart. Based on the HVC chart, a source node can find an auxiliary routing path (ARP) to indicate the direction of the journey from the source to the destination. Simulation results show that our protocol can support geographic routing efficiently, and the landmarks found by our protocol are uniformly located in the network even if some holes exist within it. In addition, our protocol is resilient to various network shapes and can find a load balancing routing path to the destination even if this path comes across holes in the network. Copyright © 2008 John Wiley & Sons, Ltd.
Analysis of numerically generated wake structures
Authors: Ivanell Stefan , Sørensen Jens N. , Mikkelsen Robert , Henningson Dan
Published: September 2008

Direct numerical simulations of the Navier–Stokes equations are performed to achieve a better understanding of the behaviour of wakes generated by wind turbines. The simulations are performed by combining the in‐house developed computer code EllipSys3D with the actuator‐line methodology. In the actuator‐line method, the blades are represented by lines along which body forces representing the loading are introduced. The body forces are determined by computing local angles of attack and using tabulated aerofoil coefficients. The advantage of using the actuator‐line technique is that it is not needed to resolve blade boundary layers and instead the computational resources are devoted to simulating the dynamics of the flow structures. In the present study, approximately 5 million mesh points are used to resolve the wake structure in a 120‐degree domain behind the turbine. The results from the computational fluid dynamics (CFD) simulations are evaluated and the downstream evolution of the velocity field is depicted. Special interest is given to the structure and position of the tip vortices. Further, the circulation from the wake flow field is computed and compared to the distribution of circulation on the blades. Copyright © 2008 John Wiley & Sons, Ltd.
Bidirectional selection for female propensity to remate in the bean beetle, Callosobruchus chinensis
Authors: Harano Tomohiro , Miyatake Takahisa
Published: September 2008

The evolution of female multiple mating, or polyandry, is difficult to comprehend and thus has been the subject of a large number of studies. However, there is only a little evidence for genetic variation in polyandry, although the evolution of a trait via selection requires genetic variation that enables the trait to respond to selection. We carried out artificial selection for increased and decreased female propensity to remate as a measure of polyandry to investigate whether this trait has a genetic component that can respond to selection in the adzuki bean beetle, Callosobruchus chinensis. Artificial selection produced responses in both directions and divergence between the selection lines in the female propensity to remate. Although the experimental design adopted in this study selected jointly for female receptivity to remating, which is a trait of females, and male ability to inhibit female remating—both of which are associated with female propensity to remate—the observed response to selection was attributable only to the female receptivity to remating. This study indicates that the female receptivity to remating has significant additive genetic variation and can evolve according to whether remating is advantageous or disadvantageous to females in C. chinensis.
Hybrid external fixation for neglected fractures of the distal radius: results after one year
Authors: Grala Paweł , Zieliński Wojciech
Published: September 2008

Background

External fixation is a well-established procedure for the treatment of unstable fractures of the distal radius, but its use is beset with complications. A plethora of theoretical and experimental data suggests that nonbridging fixators are superior for this setting. A new concept for the use of hybrid external fixation seemed reasonable and was applied for this study.

Materials and methods

We report on the first 14 cases of unstable, extraarticular fractures of the distal radius with a one-year follow-up and describe the operative technique. All were treated at 3- weeks after injury; nevertheless, closed reduction after the fixator elements were fixed to the bone was always possible.

Results

We had no intraoperative complications, but in the follow-up period three cases of algodystrophy and one transient irritation of the ulnar nerve ensued. One case developed superficial infection at the K-wire entry site that resolved with local care and systemic antibiotics. No redisplacements were observed. Early and late (at one year) evaluation of results revealed good and very good anatomic results (Lidström system) and two satisfactory (cases with algodystrophy), eight very good and four good functional outcomes (Gartland–Werley system). The patients-acceptance of the device was high.

Conclusions

Hybrid external fixation of neglected distal radial fractures results in good outcomes if care is taken to prevent overdistraction of bone fragments.
Synthesis and Visible-Light Photocatalytic Property of Bi2WO6Hierarchical Octahedron-Like Structures
Authors: Li Yuanyuan , Liu Jinping , Huang Xintang
Published: September 2008

A novel octahedron-like hierarchical structure of Bi2WO6has been fabricated by a facile hydrothermal method in high quantity. XRD, SEM, TEM, and HRTEM were used to characterize the product. The results indicated that this kind of Bi2WO6crystals had an average size of ~4 μm, constructed by quasi-square single-crystal nanosheets assembled in a special fashion. The formation of octahedron-like hierarchical structure of Bi2WO6depended crucially on the pH value of the precursor suspensions. The photocatalytic activity of the hierarchical Bi2WO6structures toward RhB degradation under visible light was investigated, and it was found to be significantly better than that of the sample fabricated by SSR. The better photocatalytic property should be strongly associated with the high specific surface area and the abundant pore structure of the hierarchical octahedron-like Bi2WO6.
Prevention of Unplanned Perioperative Hypothermia
Authors: Paulikas Cynthia A.
Published: September 2008

HYPOTHERMIA is one of the most common complications experienced by surgical patients. Better postoperative patient outcomes are achieved when normothermia is maintained.

PERIOPERATIVE NURSES should understand how to maintain normothermia, the causes of hypothermia, and adverse patient outcomes that result from hypothermia. Nursing interventions to help prevent hypothermia can be implemented during each phase of perioperative care. AORN J 88 (September 2008) 358–364. © AORN, Inc, 2008.
Volume—Outcome Relationship in Surgical Urology: Myth or Reality?
Authors: Mayer Erik K. , Bottle Alex , Athanasiou Thanos , Darzi Ara W. , Vale Justin A.
Published: September 2008

There has been much interest in the volume—outcome relationship within surgical specialities and the potential impact on service reconfiguration. Recent research has raised questions about the validity of the methodology used in existing volume—outcome studies. This review explores a methodological framework for assessing the volume—outcome relationship and discusses limitations of previous research. In particular reference is made to the existing urological literature in this field. Areas for improvement and the potential for future research are considered.
Mice lacking acid‐sensing ion channels (ASIC) 1 or 2, but not ASIC3, show increased pain behaviour in the formalin test
Authors: Staniland Amelia A. , McMahon Stephen B.
Published: September 2008

Extracellular acidification is a component of the inflammatory process and may be a factor driving the pain accompanying it. Acid‐sensing ion channels (ASICs) are neuronal proton sensors and evidence suggests they are involved in signalling inflammatory pain. The aims of this study were to (1) clarify the role of ASICs in nociception and (2) confirm their involvement in inflammatory pain and determine whether this was subunit specific.

This was achieved by (1) direct comparison of the sensitivity of ASIC1, ASIC2, ASIC3 and TRPV1 knockout mice versus wildtype littermates to acute thermal and mechanical noxious stimuli and (2) studying the behavioural responses of each transgenic strain to hind paw inflammation with either complete Freund's adjuvant (CFA) or formalin.

Naïve ASIC1−/− and ASIC2−/− mice responded normally to acute noxious stimuli, whereas ASIC3−/− mice were hypersensitive to high intensity thermal stimuli. CFA injection decreased mechanical and thermal withdrawal thresholds for up to 8days. ASIC2−/− mice had increased mechanical sensitivity on day 1 post‐CFA compared to wildtype controls. TRPV1−/− mice had significantly reduced thermal, but not mechanical, hyperalgesia on all days after inflammation. Following formalin injection, ASIC1−/− and ASIC2−/−, but not ASIC3−/− or TRPV1−/−, mice showed enhanced pain behaviour, predominantly in the second phase of the test.

These data suggest that whilst ASICs may play a role in mediating inflammatory pain, this role is likely to be modulatory and strongly dependent on channel subtype.
Mapping of yeast Rpn4p transactivation domains
Authors: Dmitry Karpov S. , Tutyaeva Vera V. , Karpov Vadim L.
Published: September 2008

The 26S proteasome is a multi‐subunit protease complex and plays an essential role in many basic cellular processes. The abundance of the 26S proteasome is controlled by a negative feedback circuit that involves the Rpn4p transcriptional activator. To date, the functional regions of Rpn4p are largely unknown. We mapped the Rpn4p transactivation domains by deletion analysis. The distal acidic domain has stronger transactivation potential than that of the proximal acidic domain. However, the N‐terminal region, and not the acidic domains of Rpn4p, is crucial for Rpn4p function. Within the N‐terminus, we mapped a novel transactivation domain, which may be regulated by some modification of lysines in a proteolysis‐independent manner.
Worldwide variation in the doubling time of Alzheimer's disease incidence rates
Authors: Ziegler-Graham Kathryn , Brookmeyer Ron , Johnson Elizabeth , Arrighi H. Michael
Published: September 2008

Background

The doubling time is the number of chronological years for the age‐specific incidence rate to double in magnitude. Doubling times describe the rate of increase of the risk of Alzheimer's disease (AD) with advancing age. Estimates of doubling times of AD assist in understanding disease etiology and forecasting future disease prevalence. The objective of this study was to investigate regional and gender differences in the doubling of AD age‐specific incidence rates.

Methods

We identified all studies in the peer review literature that reported age‐specific incidence rates for AD. We modeled the logarithm of the incidence rate as a linear function of age. We used both fixed effects models and random effects models to account for interstudy variation.

Results

AD incidence rates exponentially increase with increasing age. The overall estimate of the doubling time was 5.5 years. The doubling times from studies performed in North America and Europe were 6.0 and 5.8, respectively; whereas the doubling times in all other parts of the world were 5.0. There was no significant geographic differences in doubling times (P = .3). Although the doubling times were slightly longer for men (6.5 years) than for women (5.4 years), the difference was not significant (P = .3).

Conclusions

Doubling times of AD incidence rates are not statistically significantly different among populations throughout the world. The risk of AD grows exponentially with age, doubling approximately every 5 to 6 years. Although the shapes of the incidence curves are similar, there is considerable variation in absolute incidence rates throughout the world. Currently, there are limited epidemiologic data at the oldest ages, and further study is needed to accurately define the incidence curve above age 90.
Effects and safety of iopanoic acid in cats administered levothyroxine
Authors: Gallagher Alexander E. , Panciera David L.
Published: September 2008

The purpose of this study was to evaluate the safety and effect of iopanoic acid in 13 cats with hyperthyroidism induced by daily subcutaneous administration of 25 μg/kg levothyroxine for a period of 42 days. On day 28 of levothyroxine administration, cats were randomly allocated to receive treatment twice daily with a placebo (control group; n=4), 50 mg iopanoic acid (low dose group; n=5), or 100 mg iopanoic acid (high dose group; n=4) for 14 days. Compared to the control group, T3 concentrations were significantly decreased in both the low dose and high dose groups on days 35 and 42. T3 concentrations in the low dose and high dose groups at days 35 and 42 were not different from day −8. The effect of iopanoic acid on clinical signs of hyperthyroidism was less apparent. Further clinical studies evaluating the long-term effect in cats with spontaneous hyperthyroidism are warranted.
Some Issues Relating to Life Insurance under the Ethiopian Commercial Code
Authors: Desalegne Ezra L
Published: September 2008

This article is about some of the issues relating to life insurance based on relevant provisions of the 1960 Commercial Code and other laws of Ethiopia that are currently in force. The article first discusses the basic concepts of insurance. It then focuses on a problem attributable to the practice of the Ethiopian Insurance Corporation and five legal issues relating to life insurance. It also includes an analysis of court cases. However, due to the lack of recent Ethiopian court cases relating to life insurance, it only analyses cases from the 1970s. The article concludes with recommendations on all the issues discussed.
Generation of flat-top waveform in the time domain based on stimulated Brillouin scattering using medium with short phonon lifetime
Authors: Hasi W.L.J. , Gong S. , Lu Z.W. , Lin D.Y. , He W.M. , Fan R.Q.
Published: September 2008

A method of generating flat-top waveform in the time-domain based on stimulated Brillouin scattering (SBS) using medium with short phonon lifetime is proposed. In theory, the transmitted pulse is simulated in the case of several media with different phonon lifetime. In experiment, FC-72 and HT-270, which differ significantly in the phonon lifetime, are exploited in the experiment. Both the theoretical and experimental results indicate that, when choosing medium with short phonon lifetime, the top is almost a platform, while there is a peak in the front and a platform thereafter when choosing medium with long phonon lifetime.
Cryogenic systems for inertial fusion energy
Authors: Chatain D. , Périn J.P. , Bonnay P. , Bouleau E. , Chichoux M. , Communal D. , Manzagol J. , Viargues F. , Brisset D. , Lamaison V. , Paquignon G.
Published: September 2008

The Low Temperatures Laboratory of CEA/Grenoble (France) is involved in the development of cryogenic systems for inertial fusion since a ten of years. A conceptual design for the cryogenic infrastructure of the Laser MegaJoule (LMJ) facility has been proposed. Several prototypes have been designed, built and tested like for example the 1500 bars cryo compressor for the targets filling, the target positioner and the thermal shroud remover.

The HIPER project will necessitate the development of such equipments. The main difference is that this time, the cryogenic targets are direct drive targets. The first phase of HIPER experiments is a single shot period. Based on the experience gained the last years, not only by our laboratory but also by Omega and G.A teams, we could design the new HIPER equipments for this phase.

Some experimental results obtained with the prototypes of the LMJ cryogenic system are given and a first conceptual design for the HIPER single shot cryogenic system is shown.
Relativistic electron heating in focused multimode laser fields with stochastic phase perturbations
Authors: Mikhailov Y.A. , Nikitina L.A. , Sklizkov G.V. , Starodub A.N. , Zhurovich M.A.
Published: September 2008

We describe a direct model for simulation of relativistic electrons acceleration with a given electromagnetic field which is determined by wave packet parameters. The multimode time-spatial structure of a focused Nd-laser beam with stochastic phase disturbances of each spectral component is taken into account as a source of random forces. Electron energies of more than 10 MeV are obtained even at moderate flux densities of 1016 W/cm2. The developed numerical code makes it possible to obtain a quantitative energy distribution function in relation to both field intensity and the temporal bell-shape of the laser pulse. The efficient heating of electrons can be triggered in the presence of a counter propagating wave being reflected from the critical plasma area with a different reflection coefficient. The heating mechanism occurs with a delay relative to the beginning of the pulse when the laser fields exceed some threshold amplitudes. The qualitative comparison of simulation results with the experimental data is given as evidence that this mechanism is reasonable.
Performance of a pulsed ion beam with a renewable cryogenically cooled ion source
Authors: Renk T.J. , Mann G.A. , Torres G.A.
Published: September 2008

For operation of an ion source in an intense ion beam diode, it is desirable to form a localized and robust source of high purity. A cryogenically operated ion source has great promise, since the ions are formed from a condensed high-purity gas, which has been confined to a relatively thin ice layer on the anode surface. Previous experiments have established the principles of operation of such an ion source, but have been limited in repetitive duration due to the use of short-lived liquid He cooling of the anode surface. We detail here the successful development of a “Cryo-Diode” in which the cooling was achieved with a closed-cycle cryo-pump. This results in an ion source design that can potentially be operated for an indefinite duration. Time-of-flight measurements with Faraday cups indicate that the resultant ion beam is of high-purity, and composed of singly charged ions formed out of the gas frozen out on the anode surface.
Relating volcano morphometry to the developmental progression of Hawaiian shield volcanoes through slope and hypsometric analyses of SRTM data
Authors: Bleacher Jacob E. , Greeley Ronald
Published: September 2008

We calculated average and median slope values and produced hypsometric curves for the subaerial Hawaiian shield volcanoes using Shuttle Radar Topography Mission (SRTM) digital elevation models. The SRTM‐derived average and median slope values display similar trends to published results based on other topographic data products, showing an increase in slope relative to volcano age. Shadows in the radar data over high relief regions reduce the slope values calculated for older volcanoes that have undergone significant erosion as compared to nonradar topographic data, suggesting that SRTM data are less sensitive to studies of erosion. Both the 1 and 3 arc sec SRTM data provide comparable results showing that the nearly global 3 arc sec data can be used to conduct the same studies for other volcanoes. Hypsometric analyses show that the Hawaiian shields maintain consistent upward and lateral growth until alkalic capping and subsidence alter the relief‐surface area ratio. Changes in the morphology of the Hawaiian volcanoes are in part related to decreased magma production rates at older shields. The internal dynamics act to decrease the steadiness and duration of magma delivery to the surface causing a decrease in buffered eruptions and lava tube formation, all of which contribute to an increase in slope and relief‐surface area ratios. Terrain analyses combined with mapping can provide insight into the development of remote volcanoes or volcanoes on other planets for which remotely sensed data exist but less is known about their internal and eruptive history.
Quantifying net ecosystem carbon dioxide exchange of a short‐plant cropland with intermittent chamber measurements
Authors: Zheng Xunhua , Xie Baohua , Liu Chunyan , Zhou Zaixing , Yao Zhisheng , Wang Yinghong , Wang Yulong , Yang Lianxin , Zhu Jianguo , Huang Yao , Butterbach‐Bahl Klaus
Published: September 2008

An approach for quantifying the net ecosystem exchange (NEE) of carbon dioxide, which is subject to a rectangular hyperbolic relationship between NEE and photosynthetic active radiation, was adapted to a typical wheat‐rice rotation ecosystem under a subtropical monsoon climate in the Yangtze River delta. Adaptation schemes were established; these relied upon intermittent measurements and thereby parameterization of photosynthesis, canopy respiration, root respiration, root‐to‐shoot ratio, and plant growth, using manual chambers and conventional methods. To apply the adapted approach for NEE estimation at daily, seasonal, and annual scales, data from hourly air temperature, hourly photosynthetic active radiation, shoot biomass at maturity, measured soil heterotrophic respiration during the nonflooded growing season, and intermittently observed ecosystem respiration are all required. Indirect verification showed that this approach was capable of yielding seasonal NEE estimates comparable with those of field measurements using meteorological techniques such as eddy covariance (EC). The daily NEE fluxes were calculated for two wheat‐rice rotations. Then the total NEE during the rice‐growing seasons, the wheat‐growing seasons, the nonrice periods of the year, and the entire rotation cycles were respectively estimated as −7.08 to −7.54, −1.49 to −1.58, −0.83 to −0.92, and −7.91 to −8.46 t C ha−1 in the 2001–2002 rotation, and −7.35 to −7.82, −2.63 to −2.80, −2.17 to −2.33, and −9.51 to −10.15 t C ha−1 in the 2002–2003 rotation. Slight carbon gains occurred during the rice seasons (−0.14 to −0.62 t C ha−1), but obvious carbon losses occurred during the nonrice periods (2.27 to 3.13 t C ha−1) and over the entire rotation cycle (1.66 to 2.96 t C ha−1). These carbon losses were due to low rates of crop residue incorporation and lack of organic manure application. This study implies that the adapted approach applies for field trials requiring multiple field plots of a short‐plant ecosystem. This approach may provide a methodological alternative to fill the measurement gap for quantifying NEE on fragmented terrains at high temporal and spatial resolutions.
The Mars limited area model and simulations of atmospheric circulations for the Phoenix landing area and season of operation
Authors: Kauhanen Janne , Siili Tero , Järvenoja Simo , Savijärvi Hannu
Published: September 2008

The Mars limited area model (MLAM) has been used to simulate Martian northern polar atmospheric circulation phenomena during the planned season of the Phoenix Lander touching down on the surface (Ls ≈ 76°). Initial and boundary conditions are from Thermal Emission Spectrometer observations assimilated via the United Kingdom Mars General Circulation Model. The higher‐resolution north pole‐centric nestings (grid lengths about 17–30 km and 8.5–15 km, respectively) resolve phenomena such as shallow mesoscale katabatic drainage flows spiraling out of the cold polar dome, strong valley winds out of Chasma Borealis, and diurnal slope winds embedded on the easterly basic flow, e.g., at Phoenix landing area D. There conditions appear to be mild (for Mars) and baroclinic activity is low. Low‐level jets with wind speeds exceeding 20 m/s are, however, possible, but they are most likely nocturnal and would hence not endanger the early afternoon landing of Phoenix. Dust lifting is predicted for strong wind areas near the landing area B (where baroclinic activity appears to be high) and in the general area of the landing area D, primarily east of it.
Comparison of two soil temperature algorithms for a bare ground site on the Loess Plateau in China
Authors: Gao Zhiqiu , Lenschow Donald H. , Horton Robert , Zhou Mingyu , Wang Linlin , Wen Jun
Published: September 2008

Two thermal transfer algorithms for soil are used to investigate the diurnal vertical temperature variation in the common case of a vertically heterogeneous thermal diffusivity and the considerable liquid water flux which generally exists in soil when surface evaporation is large. One algorithm assumes that soil is vertically homogenous and takes into account only thermal conduction, and the other, developed in our recent study, considers the vertical heterogeneity of thermal diffusivity in soil and couples thermal conduction and convection (e.g., heat transfer by water flux). Theoretically the two methods are identical for vertically homogenous dry soil. On the basis of soil temperature data collected at a bare soil site over the Loess Plateau of China during the period from DOYs 197 to 241, 2005, we found that the new algorithm gives a realistic estimate of soil temperature while the previous one, on average, overestimates either the diurnal amplitude by 0.95 K or the phase shift by 0.207 rad (i.e., 47.44 min) at the soil depth of 0.10 m. Using the new algorithm and measurements of soil temperature, we determine the soil thermal diffusivity and a variable that represents the sum of the vertical gradient of soil thermal diffusivity and water flux density at three levels within the first 0.40 m of the soil surface. We also simulate the soil temperature for the depths of 0.20 m and 0.40 m, and the results are in satisfactory agreement with direct measurements. The main contribution here is to provide analytic insight into the role of heterogeneity and some simple formulae as tools for interpretation of the role of heterogeneity in observed diurnal temperature variations.
Paleoclimate proxy perspective on Caribbean climate since the year 1751: Evidence of cooler temperatures and multidecadal variability
Authors: Kilbourne K. H. , Quinn T. M. , Webb R. , Guilderson T. , Nyberg J. , Winter A.
Published: September 2008

Annually resolved coral δ18O and Sr/Ca records from southwestern Puerto Rico are used to investigate Caribbean climate variability between 1751 and 2004 C.E. Mean surface ocean temperatures in this region have increased steadily by about 2°C since the year 1751, with Sr/Ca data indicating 2.1 ± 0.8°C and δ18O data indicating 2.7 ± 0.5°C. Coral geochemical records from across the tropics demonstrate that regional variability is important for understanding climate variations at centennial time scales. A strong multidecadal salinity signal in the oxygen isotope data correlates with observed multidecadal temperature variations in the Northern Hemisphere. Instrumental wind and precipitation data indicate that the most recent coral isotopic variations are caused by expansion and contraction of the steep regional salinity gradient, forced by trade wind anomalies through meridional Ekman transport. The timing of the fluctuations suggests that the multidecadal‐scale wind and surface circulation anomalies might play a role in Atlantic temperature variability and meridional overturning circulation, but further work is needed to confirm this suggestion.
Supramolecular organization of the yeast F1Fo‐ATP synthase
Authors: Thomas Daniel , Bron Patrick , Weimann Théodore , Dautant Alain , Giraud Marie‐France , Paumard Patrick , Salin Bénédicte , Cavalier Annie , Velours Jean , Brèthes Daniel
Published: September 2008

Background information. The yeast mitochondrial F1Fo‐ATP synthase is a large complex of 600 kDa that uses the proton electrochemical gradient generated by the respiratory chain to catalyse ATP synthesis from ADP and Pi. For a large range of organisms, it has been shown that mitochondrial ATP synthase adopts oligomeric structures. Moreover, several studies have suggested that a link exists between ATP synthase and mitochondrial morphology.

Results and discussion. In order to understand the link between ATP synthase oligomerization and mitochondrial morphology, more information is needed on the supramolecular organization of this enzyme within the inner mitochondrial membrane. We have conducted an electron microscopy study on wild‐type yeast mitochondria at different levels of organization from spheroplast to isolated ATP synthase complex. Using electron tomography, freeze‐fracture, negative staining and image processing, we show that cristae form a network of lamellae, on which ATP synthase dimers assemble in linear and regular arrays of oligomers.

Conclusions. Our results shed new light on the supramolecular organization of the F1Fo‐ATP synthase and its potential role in mitochondrial morphology.
Geminin is partially localized to the centrosome and plays a role in proper centrosome duplication
Authors: Lu Fei , Lan Rongfeng , Zhang Hongyin , Jiang Qing , Zhang Chuanmao
Published: September 2008

Background information. Centrosome duplication normally parallels with DNA replication and is responsible for correct segregation of replicated DNA into the daughter cells. Although geminin interacts with Cdt1 to prevent loading of MCMs (minichromosome maintenance proteins) on to the replication origins, inactivation of geminin nevertheless causes centrosome over‐duplication in addition to the re‐replication of the genome, suggesting that geminin may play a role in centrosome duplication. However, the exact mechanism by which loss of geminin affects centrosomal duplication remains unclear and the possible direct interaction of geminin with centrosomal‐localized proteins is still unidentified.

Results. We report in the present study that geminin is physically localized to the centrosome. This unexpected geminin localization is cell‐cycle dependent and mediated by the actin‐related protein, Arp1, one subunit of the dynein—dynactin complex. Disruption of the integrity of the dynein—dynactin complex by overexpression of dynamitin/p50, a well‐characterized inhibitor of dynactin, reduces the centrosomal localization of both geminin and Arp1. Enrichment of geminin on centrosomes was enhanced when cellular ATP production was suppressed in the ATP‐inhibitor assay, whereas the accumulation of geminin on the centrosome was disrupted by depolymerization of the microtubules using nocodazole. We further demonstrate that the coiled‐coil motif of geminin is required for its centrosomal localization and the interaction of geminin with Arp1. Depletion of geminin by siRNA (small interfering RNA) in MDA‐MB‐231 cells led to centrosome over‐duplication. Conversely, overexpression of geminin inhibits centrosome over‐duplication induced by HU in S‐phase‐arrested cells, and the coiled‐coil‐motif‐mediated centrosomal localization of geminin is required for its inhibition of centrosome over‐duplication. Centrosomal localization of geminin is conserved among mammalian cells and geminin might perform as an inhibitor of centrosome duplication.

Conclusions. The results of the present study demonstrate that a fraction of geminin is localized on the centrosome, and the centrosomal localization of geminin is Arp1‐mediated and dynein—dynactin‐dependent. The coiled‐coil motif of geminin is required for its targeting to the centrosome and inhibition of centrosome duplication. Thus the centrosomal localization of geminin might perform an important role in regulation of proper centrosome duplication.
Expression characterization and actual function of the second pucBA in Rhodobacter sphaeroides
Authors: Wang Wanneng , Hu Zongli , Li Jinzhe , Chen Guoping
Published: September 2008

The puc2BA operon of Rhodobacter sphaeroides is highly similar to the original puc1BA operon. Genetic, biochemical and spectroscopic approaches were used to investigate the function of puc2BA; the puc1BA and puc2BA structural genes were amplified and cloned into the pRK415 vector controlled by the puc promoter from R. sphaeroides, which was then introduced into R. sphaeroides mutant strains. The results indicated that puc2BA was normally expressed and puc2BA-encoded polypeptides were assembled into membrane LHII (light-harvesting II) complexes, although the puc2A-encoded polypeptide was much larger than the puc1A-encoded polypeptide. Semi-quantitative RT-PCR (reverse transcription-PCR) and SDS/PAGE indicated that puc1BA and puc2BA were expressed in R. sphaeroides when integrated into the genome or expressed from vectors. Furthermore, the polypeptides from the puc1BA and puc2BA genes were both involved in LHII assembly, and pucC is also necessary to assemble LHII complexes. Nevertheless, the LHII complexes synthesized from puc2BA in R. sphaeroides have blue-shift absorption bands at 801 and 846 nm.
Distribution of iron in multicrystalline silicon ingots
Authors: Kvande R. , Geerligs L. J. , Coletti G. , Arnberg L. , Di Sabatino M. , Øvrelid E. J. , Swanson C. C.
Published: September 2008

The distribution of iron in multicrystalline silicon ingots for solar cells has been studied. A p- and a n-type multicrystalline ingot were intentionally contaminated by adding 53ppmwt (μg∕g) of iron to the silicon feedstock and compared to a reference p-type ingot produced from ultrapure silicon feedstock. The vertical total iron distribution was determined by neutron activation analysis and glow discharge mass spectrometry. For the intentionally Fe-contaminated ingots, the distribution can be described by Scheil’s equation with an effective distribution coefficient of 2×10−5. The interstitial iron concentration was measured in the p-type ingots. In the Fe-contaminated ingot, it is almost constant throughout the ingot and constitutes about 50% of the total concentration, which is in conflict with the previous studies. Gettering had a large impact on the interstitial iron levels by reducing the concentration by two orders of magnitude. Considerable trapping was observed at crystal defects on as-cut wafers from the same ingot. The trapping was suppressed by gettering. The back diffusion of iron from the ingot top after complete solidification was modeled and found to affect the iron concentration up to a distance of approximately 17mm into the ingot. The interstitial as well as the total iron concentration of the reference ingot were extremely low and difficult to measure accurately.
Evidence of complete band gap and resonances in a plate with periodic stubbed surface
Authors: Wu Tsung-Tsong , Huang Zi-Gui , Tsai Tzu-Chin , Wu Tzung-Chen
Published: September 2008

In this paper, we numerically and experimentally demonstrate the existence of complete band gaps and resonances in a plate with a periodic stubbed surface. Numerical results show that a complete band gap forms as the stub height reaches about three times the plate thickness. In the experiment, we used a pulsed laser to generate broadband elastic waves and used optical devices as well as point piezoelectric transducers to detect wave signals. The results show that the numerical predictions are in very good agreement with those measured experimentally. Remarkable resonances on the top surface of the stubs are found and discussed.
Potential of mean force between charged colloids: Effect of dielectric discontinuities
Authors: Reščič Jurij , Linse Per
Published: September 2008

The potential of mean force between two spherical and like-charged macroions in a salt-free aqueous solution has been determined using an extended primitive model and canonical Monte Carlo simulations. The systems considered covered the range from a purely repulsive to a purely attractive potential of mean force as the electrostatic coupling was increased. The macroions were modeled as spherical dielectric cavities, and the polarization surface charge densities occurring at the dielectric discontinuities were expanded in spherical harmonics. The surface polarization gave rise to (i) an attenuation of the counterion accumulation at the macroion surfaces at all cases considered, (ii) an enhanced repulsive potential of mean force in the weak to intermediate electrostatic coupling regime, and (iii) a less attractive at short separation and an enhanced attractive potential of mean force at longer macroion-macroion separation in the strong electrostatic coupling regime.
Inelastic electron transport in polymer nanofibers
Authors: Zimbovskaya Natalya A.
Published: September 2008

In this paper we present theoretical analysis of the electron transport in conducting polymers being in a metal-like state. We concentrate on the study of the effects of temperature on characteristics of the transport. We treat a conducting polymer in the metal state as a network of metalliclike grains embedded in poorly conducting environment, which consists of randomly distributed polymeric chains. We carry out the present studies assuming that the intergrain conduction is mostly provided by electron quantum tunneling via intermediate states localized on polymer chains between the grains. To analyze the effects of temperature on this kind of electron intergrain transport we represent the thermal environment as a phonon bath coupled to the intermediate state. The electron transmission is computed using the Buttiker model within the scattering matrix formalism. This approach is further developed, and the dephasing parameter is expressed in terms of relevant energies including the thermal energy. It is shown that temperature dependencies of both current and conductance associated with the above transport mechanism differ from those typical for other conduction mechanisms in conducting polymers. This could be useful to separate out the contribution from the intergrain electron tunneling to the net electric current in transport experiments on various polymer nanofibers. The proposed model could be used to analyze inelastic electron transport through molecular junctions.
Kinetics and microstructure associated with nonisothermal nucleation and growth processes
Authors: Rickman J. M. , Gunton J. D.
Published: September 2008

The impact of nonisothermal conditions on the kinetics and microstructure associated with a first-order phase transformation is investigated using simulation and a correlation function formalism. More specifically, equal-time correlation functions and microstructural descriptors of grain area are calculated using an N-fold Monte Carlo simulation and compared directly with their theoretical counterparts for a range of heating rates. Finally, connections between these results and those obtained experimentally via calorimetry and microscopy are discussed.
Superior imaging resolution in scanning helium-ion microscopy: A look at beam-sample interactions
Authors: Cohen-Tanugi David , Yao Nan
Published: September 2008

Scanning helium-ion microscopy (SHIM) offers high-resolution imaging at the subnanometer scale. We employ Monte Carlo simulations to show the characteristics of the beam-sample interaction involved in SHIM, and compare it with those of scanning electron microscopy and scanning gallium-ion microscopy. We discuss the electronic and nuclear stopping powers and demonstrate that helium ions in matter possess a distinctive “electronic loss phase” in which inelastic collisions strongly dominate. This allows for large penetration depth, localized secondary electron emission, and high signal-to-noise ratio. We investigate the energy dependence of the interaction volume and show that for SHIM, spatial resolution can be further increased with energies beyond the customary 30keV level. This paper provides a better understanding of the physics of SHIM and its conditions for high performance.
Tungsten carbide revisited: New anion photoelectron spectrum and density functional theory calculations
Authors: Rothgeb David , Hossain Ekram , Jarrold Caroline Chick
Published: September 2008

A new anion photoelectron (PE) spectrum of WC− is presented and analyzed using existing and new calculations. This spectrum is different from the PE spectrum previously published [X. Li et al., J. Chem. Phys. 111, 2464 (1999)], which we suggest was actually the PE spectrum of W−. The ground anion state is determined by calculations and comparison with spectral features to be the Δ3∕22 state. The Δ13−Δ3∕22 transition is observed at an electron binding energy of 2.155eV, which corresponds to the adiabatic electron affinity of WC. The bond length of the anion is determined to be 1.771(5)Å. A number of spectral assignments corresponding to both excited anion and neutral states are made based on previously obtained fluorescence spectra [S. M. Sickafoose et al., J. Chem. Phys. 116, 993 (2002)] and density functional theory calculations.
Iterative linearized approach to nonadiabatic dynamics
Authors: Dunkel E. R. , Bonella S. , Coker D. F.
Published: September 2008

This paper presents a new approach to propagating the density matrix based on a time stepping procedure arising from a Trotter factorization and combining the forward and backward incremental propagators. The sums over intermediate states of the discrete quantum subsystem are implemented by a Monte Carlo surface hopping-like procedure, while the integrals over the continuous variables are performed using a linearization in the difference between the forward and backward paths of these variables leading to classical-like equations of motion with forces determined by the quantum subsystem states. The approach is tested on several models and numerical convergence is explored.
Pressure-induced piezoelectric effects in near-lattice-matched GaN/AlInN quantum wells
Authors: Kamińska A. , Franssen G. , Suski T. , Feltin E. , Grandjean N.
Published: September 2008

Near-lattice-matched GaN/AlInN multiple quantum wells (MQWs) are investigated by means of the diamond anvil cell high-pressure technique. The hydrostatic pressure dependence of the photoluminescence dEPL/dp and the variation in the PL peak energy with the QW width for different pressures were measured. Taking into account the influence of a large Stokes shift on the correct determination of the built-in electric field value, we find that the electric field, equal to 4.2±1.1 MV/cm at ambient pressure, increases with pressure at a rate of 0.29 MV/(cm GPa). This value is in reasonable agreement with the theoretically predicted value, based on nonlinear elasticity, of 0.17 MV/(cm GPa). Interestingly, the observed behavior is very similar to strongly mismatched GaN/AlGaN QWs with a similar band offset, indicating that in GaN/AlInN QWs there is still a pressure dependence of piezoelectric effects, in spite of ambient-pressure lattice matching.