bluuebunny/crossref_metadata_2025 huggingface dataset:
Regulation of EGF receptor signaling by the MARVEL domain‐containing protein CKLFSF8
Authors: Jin Caining , Ding Peiguo , Wang Ying , Ma Dalong
Published: October 2005

It is known that chemokine‐like factor superfamily 8 (CKLFSF8), a member of the CKLF superfamily, has four putative transmembrane regions and a MARVEL domain. Its structure is similar to TM4SF11 (plasmolipin) and widely distributed in normal tissue. However, its function is not yet known. We show here that CKLFSF8 is associated with the epidermal growth factor receptor (EGFR) and that ectopic expression of CKLFSF8 in several cell lines suppresses EGF‐induced cell proliferation, whereas knockdown of CKLFSF8 by siRNA promotes cell proliferation. In cells overexpressing CKLFSF8, the initial activation of EGFR was not affected, but subsequent desensitization of EGF‐induced signaling occurred rapidly. This attenuation was correlated with an increased rate of receptor endocytosis. In contrast, knockdown of CKLFSF8 by siCKLFSF8 delayed EGFR endocytosis. These results identify CKLFSF8 as a novel regulator of EGF‐induced signaling and indicate that the association of EGFR with four transmembrane proteins is critical for EGFR desensitization.
Evidence from the Rio Bayo valley on the extent of the North Patagonian Icefield during the Late Pleistocene–Holocene Transition
Authors: Glasser Neil F. , Harrison Stephan , Ivy-Ochs Susan , Duller Geoffrey A.T. , Kubik Peter W.
Published: October 2005

This paper presents data on the extent of the North Patagonian Icefield during the Late Pleistocene–Holocene transition using cosmogenic nuclide exposure age and optically stimulated luminescence dating. We describe geomorphological and geochronological evidence for glacier extent in one of the major valleys surrounding the North Patagonian Icefield, the Rio Bayo valley. Geomorphological mapping provides evidence for the existence of two types of former ice masses in this area: (i) a large outlet glacier of the North Patagonian Icefield, which occupied the main Rio Bayo valley, and (ii) a number of small glaciers that developed in cirques on the slopes of the mountains surrounding the valley. Cosmogenic nuclide exposure-age dating of two erratic boulders on the floor of the Rio Bayo valley indicate that the outlet glacier of the icefield withdrew from the Rio Bayo valley after 10,900 ± 1000 yr (the mean of two boulders dated to 11,400 ± 900 yr and 10,500 ± 800 yr). Single-grain optically stimulated luminescence (OSL) dating of an ice-contact landform constructed against this glacier indicates that this ice mass remained in the valley until at least 9700 ± 700 yr. The agreement between the two independent dating techniques (OSL and cosmogenic nuclide exposure age dating) increases our confidence in these age estimates. A date obtained from a boulder on a cirque moraine above the main valley indicates that glaciers advanced in cirques surrounding the icefield some time around 12,500 ± 900 yr. This evidence for an expanded North Patagonian Icefield between 10,900 ± 1000 yr and 9700 ± 700 yr implies cold climatic conditions dominated at this time.
The Investigation of Optimal Experience and Apathy
Authors: Delle Fave Antonella , Massimini Fausto
Published: October 2005

Abstract. Individuals, as living open systems, actively interact with their environment. Throughout their life, they preferentially replicate a subset of the available opportunities for action. This process has been labeled psychological selection, and it is based on the quality of experience reported in daily situations. Empirical evidence has shown that individuals preferentially select, reproduce, and cultivate the activities associated with optimal experience, a distinctively positive and complex state of consciousness characterized by the perception of high challenges balanced with adequate skills, concentration and engagement, clear goals and rules, and control of the situation. From this perspective, optimal experience fosters the development of individual competencies, shaping the pattern of psychological selection. Empirical evidence was also gathered for apathy, the negative pole of experience fluctuation, characterized by disengagement, disruption of attention, negative affect, and low perceived challenges. This paper will provide findings concerning the psychological features of optimal experience and apathy across different samples and activities. A stable cognitive core was detected for both states, around which affective and motivational variables fluctuate according to the structure of the associated activities. The regulating function of short-term desirability and perceived long-term goals on the quality of experience was also highlighted. Results suggested that the association of optimal experiences and skill cultivation with structured and long-term meaningful activities could be used as an intervention tool for the promotion of individual development and social integration in youth and adults.
Affective and Social Self- Regulatory Efficacy Beliefs as Determinants of Positive Thinking and Happiness
Authors: Caprara Gian Vittorio , Steca Patrizia
Published: October 2005

Abstract. In line with prior work, the present study aimed at examining a conceptual model positing that affective and social self-regulatory efficacy beliefs influence one's cognitive and affective components of subjective well-being, namely, positive thinking and happiness. Positive thinking corresponds to the latent dimension underlying life satisfaction, self-esteem, and optimism. Happiness, instead, corresponds to the difference between positive and negative affect, as they are experienced in a variety of daily life situations. The study was conducted on 683 Italian adults belonging to six different age groups. The findings of the study corroborated the paths of relations linking the examined variables.
Childhood Roots of Women's Subjective Well-Being
Authors: Daukantaite Daiva , Bergman Lars R.
Published: October 2005

Abstract. The focus of the study is on the importance of early optimism for adult subjective well-being (SWB). Only females were studied. Data from age 13 and age 43 were taken from the Swedish longitudinal research program Individual Development and Adaptation (IDA, Magnusson, 1988 ). We investigated the longitudinal relationship between early optimism and optimism at age 43, its mediation via positive and negative affect measured at age 43, and finally the “effect” on global life satisfaction at age 43. For this purpose, structural equation methodology was used and the fit indices were compared among three extended cognitive-affective models, based on Chang's work ( Chang, 2002 ). The best fitting model suggests that early optimism influences optimism at middle age, which in its turn has both a direct influence on global life satisfaction and an indirect influence via the negative affect dimension. In further analyses we studied the importance of early optimism for adult SWB in relation to the importance of a number of other factors measured in adolescence. Optimism at age 13 was the only factor that was consistently related to women's SWB at age 43.
The Role of Family Background, School Success, and Career Orientation in the Development of Sense of Coherence
Authors: Feldt Taru , Kokko Katja , Kinnunen Ulla , Pulkkinen Lea
Published: October 2005

Abstract. This study investigates family background (child-centered parenting, parental socioeconomic status), school success in adolescence, and career orientation (education, stability of career line) in adulthood as antecedents of adult sense of coherence (SOC; Antonovsky, 1987a ), which has been posited to be a disposition crucial to understanding individual differences in successful coping with stress. Participants (104 men and 98 women) were drawn from the ongoing Jyväskylä Longitudinal Study of Personality and Social Development (JYLS), which was started when the participants were 8- or 9-year-old children (in 1968). Data gathered at ages 14, 27, 36, and 42 were used in this study. The results of structural equation modeling (SEM) indicated that child-centered parenting in adolescence and a stable career line in adulthood were directly associated with a high SOC at age 42. In addition, child-centered parenting, high parental socioeconomic status, and school success at age 14 were indirectly associated with adult SOC via education and stability of career line. The SEM multigroup comparison showed that the obtained associations were similar for men and women.
Combining Work and Family Life
Authors: Schoon Ingrid , Hansson Leeni , Salmela-Aro Katariina
Published: October 2005

Abstract. The aim of this paper is to investigate whether the combination of paid employment and taking care of children promotes or challenges the life satisfaction of married and divorced men and women in the UK, Estonia, and Finland. The UK sample stems from the National Child Development Study, at age 42 (N = 10280; 48% of men, 52% of women). The Estonian data come from a representative sample of 1164 participants (507 men, 657 women; mean age 42). The Finnish data stems from an ongoing longitudinal study on 1390 participants (447 men and 943 women; mean age = 41). The results showed that in all three countries women report higher levels of life satisfaction than men, couples are generally more satisfied than divorcees, and those who are employed are generally more satisfied with their lives than those who are not. Second, for men in general as well as for divorced women higher levels of life satisfaction appear to be associated with full-time work. Third, men and women pursuing a professional career are more satisfied with their lives than men and women in unskilled jobs. Finally, having a child shows no significant association with life satisfaction in any of our three countries, although there were significant interactions between gender, marital status, employment, and parenthood. Divorced women in all three countries appear to be more satisfied with their lives if they do not have children, especially after adjusting life satisfaction by occupational status. Findings are discussed with regard to role stress and role accumulation theories.
Positive Adult Personality Development
Authors: Staudinger Ursula M. , Kunzmann Ute
Published: October 2005

Abstract. Does personality stay stable after young adulthood or is there continued change throughout middle and later adulthood? For decades, this question has caused heated debate. Over the last couple of years, a consensus has emerged based on recent cross-cultural as well as longitudinal evidence. This consensus confirms that indeed there is personality change in middle and later adulthood. Many authors have labeled this change personality maturation or growth. In somewhat simplified terms the observed pattern is as follows: neuroticism declines, conscientiousness and agreeableness increase. At the same time it has been argued that this pattern of personality change is the result of coping with the developmental tasks of adulthood and, thus, increased adjustment. We would like to examine this practice of equating developmental adjustment with growth and ask how to define personality growth. To answer this question, we consult theories of personality development as well as lifespan theory.
Ensemble forecast of the Kuroshio meandering
Authors: Miyazawa Yasumasa , Yamane Shozo , Guo Xinyu , Yamagata Toshio
Published: October 2005

Focusing on predictability of the Kuroshio meandering, we have done an ensemble forecast experiment; the application of the method to the problem addressed seems to be the first comprehensive attempt in the community of physical oceanography. By assimilating sea surface height anomaly into an ocean general circulation model in the preceding 40‐day period, the observed Kuroshio meandering manifested south of Japan in November 1999 was successfully predicted 2 months before the event. The experiment yields a forecasting skill of the Kuroshio meander position for 60 days in the sense that the RMS error does not exceed the magnitude of the model climatic variation and those obtained from the non‐assimilated simulation and persistence. In addition to a single trajectory forecast experiment, ensemble forecasts were conducted using 10 perturbed initial states generated by the breeding method. The predicted states realized as the ensemble members of the 80‐day forecast are classified into two categories: large and non‐large meander. It is found that the intensity of an anticyclonic eddy in the initial state seems to play a key role in selecting one of the two states.
Simulation of the electrification of winter thunderclouds using the three‐dimensional Regional Atmospheric Modeling System (RAMS) model: Single cloud simulations
Authors: Altaratz Orit , Reisin Tamir , Levin Zev
Published: October 2005

The formulation of cloud electrification is introduced for the first time into the three‐dimensional Regional Atmospheric Modeling System (RAMS) mesoscale forecast model. As a first step, this paper deals with the electrical development in an isolated thunderstorm. A subsequent paper will deal with the electrical development in a cloud field. As an example, for this demonstration we chose wintertime conditions off the northern coast of Israel. Simulations of the charge separation in thunderclouds and the evolution of the electric field were conducted until the conditions for lightning were met. The numerical formulation of the electrical processes includes only the parameterization of the noninductive graupel‐ice charge separation mechanism. Two different parameterizations of the charge separation by the noninductive charging mechanism were compared. The first was based on the experimental studies of Saunders et al. (1991) and the other on the experimental results of Takahashi (Takahashi (1978) and Takahashi and Miyawaki (2002)). The numerical results show that Takahashi's scheme produces a tripolar charge distribution in the cloud, prior to the first lightning flash. The Saunders' parameterization produces an inverted dipole before the lightning time. The charging rate was similar in both schemes.
Retrieval of stratospheric NO3 vertical profiles from SCIAMACHY lunar occultation measurement over the Antarctic
Authors: Amekudzi L. K. , Sinnhuber B.‐M. , Sheode N. V. , Meyer J. , Rozanov A. , Lamsal L. N. , Bovensmann H. , Burrows J. P.
Published: October 2005

NO3 vertical profiles have been retrieved over the Antarctic (60°–90°S) from the Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) lunar occultation spectra, using the visible spectral band (610–680 nm) containing NO3 absorption bands at 623 and 662 nm. The retrieved NO3 profiles agree well with calculations from a photochemical model constrained by retrieved O3 and analyzed temperatures in the altitude range between 24 and 45 km. Below about 35–40 km, observed NO3 is well reproduced by photochemical steady state calculations. Differences between observed and modeled NO3 are within the estimated accuracy of 20–35%, demonstrating the consistency of the NO3 retrieval and model.
Quaternary upper ocean thermal gradient variations in the South China Sea: Implications for east Asian monsoon climate
Authors: Tian Jun , Wang Pinxian , Chen Ronghua , Cheng Xinrong
Published: October 2005

The east Asian monsoon climate has an overwhelming influence on local climatic conditions of the South China Sea (SCS). Here we present results from a 3‐year study of modern sediment traps from the central SCS in which the percentage of opal, the fluxes of Pulleniatina obliquiloculata and Globigerinoides ruber, the organic carbon flux, and primary productivity all show highest values during winter when the mixed layer depth is deepest. The δ18O difference (Δδ18O(P‐G)) between the subsurface dwelling P. obliquiloculata and the mixed layer dwelling G. ruber in core top samples from 12 piston cores and one Ocean Drilling Program (ODP) site in the SCS is large, ∼0.6‰ in a cold eddy area with a shallow mixed layer off Vietnam, but is reduced in deep mixed layer settings lacking cold eddies. We also present 1.56 Myr‐long isotope records of G. ruber and P. obliquiloculata from ODP site 1143 in the southern SCS that reveal upper ocean thermal gradient variations during the Quaternary. Lower Δδ18O(P‐G) values indicate increased mixed layer depths over most glacial episodes, likely due to stronger winter monsoon winds. In contrast, higher Δδ18O(P‐G) values during interglacial intervals suggest decreased mixed layer depths and thus weaker winter monsoon winds. Comparisons of Δδ18O(P‐G) with the percentage of P. obliquiloculata at site 1143 and the percentage of herbs and opal flux at site 1144 demonstrate that glacial‐interglacial variations were strongly influenced by stronger and weaker east Asian winter monsoons during glacials and interglacials, respectively. Therefore the upper ocean thermal gradient variations in the SCS have been consistently affected by the east Asian winter monsoon since at least the beginning of the Pleistocene.
Mélange and its seismogenic roof décollement: A plate boundary fault rock in the subduction zone—An example from the Shimanto Belt, Japan
Authors: Kitamura Yujin , Sato Katsushi , Ikesawa Eisei , Ikehara‐Ohmori Kotoe , Kimura Gaku , Kondo Hideki , Ujiie Kohtaro , Onishi Celia Tiemi , Kawabata Kuniyo , Hashimoto Yoshitaka , Mukoyoshi Hideki , Masago Hideki
Published: October 2005

The Mugi Mélange located in western Shikoku of the Shimanto Belt shows systematic Y‐P deformation fabrics formed by microshear and pressure solution that penetrate throughout the mélange pile. Magnetic susceptibility ellipsoids obtained from the anisotropy of magnetic susceptibility (AMS) are highly oblate. Maximum and minimum axes of the ellipsoids are consistent with the shear orientation of the mélange and the mean pole of P surfaces, respectively. This agreement suggests that the Mugi Mélange was formed as a result of underthrusting of trench filling sediment. Vitrinite reflectance ranges from 2.52% to 3.08%, which corresponds to a maximum paleotemperature of ∼180–200°C. Pseudotachylyte, evidence of a seismogenic slip, was found in the upper boundary roof fault of the Mugi Mélange. However, there is not a thermal gap between the mélange and the overlying coherent piles, and the temperature from vitrinite reflectance gradually rises downward from the coherent piles to the mélange beyond the boundary fault, which suggests that paleoisotherms parallel the boundary fault orientation. The isotherms in the seismogenic zone are estimated as subparallel to the plate boundary décollement. Therefore the setting of the cataclastic boundary fault, which includes pseudotachylyte, appears to be a major plate boundary thrust or a subhorizontal splay fault. A probable geologic setting that accounts for the Mugi Mélange and the seismogenic roof fault is partitioning of the slip along the plate boundary fault in space and time: interseismic slip in the mélange and seismic slip along the roof fault.
Bayesian generalized least squares regression with application to log Pearson type 3 regional skew estimation
Authors: Reis D. S. , Stedinger J. R. , Martins E. S.
Published: October 2005

This paper develops a Bayesian approach to analysis of a generalized least squares (GLS) regression model for regional analyses of hydrologic data. The new approach allows computation of the posterior distributions of the parameters and the model error variance using a quasi‐analytic approach. Two regional skew estimation studies illustrate the value of the Bayesian GLS approach for regional statistical analysis of a shape parameter and demonstrate that regional skew models can be relatively precise with effective record lengths in excess of 60 years. With Bayesian GLS the marginal posterior distribution of the model error variance and the corresponding mean and variance of the parameters can be computed directly, thereby providing a simple but important extension of the regional GLS regression procedures popularized by Tasker and Stedinger (1989), which is sensitive to the likely values of the model error variance when it is small relative to the sampling error in the at‐site estimator.
Tracer model identification using artificial neural networks
Authors: Akin Serhat
Published: October 2005

The derivation of transport parameters from tracer tests conducted in geothermal systems will depend strongly on the conceptual and mathematical model that is fitted to the data. Depending on the model employed the estimation of transport parameters (porosity and dispersivity of the fracture network, porosity of the matrix) may result in a significant variation in dispersivity. If the results from such tracer tests are to be used in parameter selection for larger‐scale models, it is crucial that the tracer test is itself interpreted with an appropriate model. In order to tackle this problem, artificial neural network (ANN) technology is proposed. A dual‐layer neural network model was trained using synthetic tracer test data generated using analytical one‐dimensional homogeneous, double‐porosity pseudosteady state, multifracture, and fracture matrix models. The developed model was then used to identify several actual tracer tests conducted in various geothermal reservoirs reported in the literature. In most cases it was observed that the model successfully identified a wide variety of reservoir models. In some cases the model decreased the number possible models to two. It was also observed that ANN results were in accord with least squares analysis.
Analytical solutions for surfactant‐enhanced remediation of nonaqueous phase liquids
Authors: LaForce Tara , Johns Russell T.
Published: October 2005

Benchmark compositional solutions are presented for the remediation of aquifers contaminated with nonaqueous phase liquids (NAPLs) by injection of surfactant‐water mixtures. The method of characteristics (MOC) is used to find one‐dimensional analytical solutions to the Riemann problem where three partially miscible phases are flowing in a Winsor type III microemulsion. In partially miscible flow, two or three phases form when the components (constituents) are mixed in some but not all proportions. Three relative permeability models are examined, and MOC solutions are found. Fine‐grid numerical simulations match the MOC results. The composition routes and contaminant recoveries can differ significantly depending on the relative permeability model used. The results for each model are optimized to determine the minimum surfactant volume required for complete contaminant recovery. Unlike two‐phase partially miscible flow, the presence of three flowing phases makes it impossible to reach miscibility between the injected and resident fluids, regardless of surfactant concentration.
Radiative effect of surface albedo change from biomass burning
Authors: Myhre Gunnar , Govaerts Yves , Haywood Jim M. , Berntsen Terje K. , Lattanzio Alessio
Published: October 2005

The radiative impact of burn scars from biomass is investigated. Changes in surface albedo derived from satellite observations over the African continent are used as a first order indication of this impact. Because the direct radiative effect of aerosols from biomass burning is dependent on the underlying surface albedo, we investigate the interaction of the direct radiative effect due to biomass burning aerosols with the change in surface reflection due to the burn scars. The radiative effect of reduced surface albedo from burn scars is estimated to be close to 0.1 Wm−2 over a region covering the African continent.
Onset and withdrawal of Indian summer monsoon
Authors: Prasad V. S. , Hayashi Taiichi
Published: October 2005

The onset of the Indian summer monsoon (ISM) is defined in terms of zonal asymmetric temperature anomaly and withdrawal is defined in terms of vertical wind shear between 850 hPa and 200 hPa. The onset and withdrawal dates determined by these two indexes are also consistent with the onset/withdrawal timing of the real monsoon circulation. The onset and withdrawal day values are also reasonably correlated with the strength of the monsoon and to some of its boundary forcings such as SST anomalies over the Nino‐3 and Bay of Bengal regions. Thus the proposed criteria are both physically and practically viable to study the interannual variability of the Indian summer monsoon.
Simulating the Martian dust cycle with a finite surface dust reservoir
Authors: Kahre M. A. , Murphy J. R. , Haberle R. M. , Montmessin F. , Schaeffer J.
Published: October 2005

Multiple year General Circulation Model (GCM) simulations that include a finite surface dust reservoir and an infinite surface dust reservoir are compared. While the infinite dust reservoir simulations produce a highly repeatable annual dust cycle, the finite surface dust reservoir simulations evolve quickly towards a low‐ dust condition. Once a region is swept clean of available surface dust, it reacquires only small amounts of dust during northern summer but it is repeatedly swept clean during each subsequent dust storm season (southern spring and summer). This argues against a finite dust reservoir as a mechanism for the interannual variability of global dust storms. Additionally, these results suggest that the regions of preferred wind stress lifting are deep dust reservoirs that are not depleted and resupplied on annual or decadal timescales. Therefore, the dust cycle must be closed on much longer timescales, possibly those associated with orbital variations.
Marine boundary layer clouds at the heart of tropical cloud feedback uncertainties in climate models
Authors: Bony Sandrine , Dufresne Jean‐Louis
Published: October 2005

The radiative response of tropical clouds to global warming exhibits a large spread among climate models, and this constitutes a major source of uncertainty for climate sensitivity estimates. To better interpret the origin of that uncertainty, we analyze the sensitivity of the tropical cloud radiative forcing to a change in sea surface temperature that is simulated by 15 coupled models simulating climate change and current interannual variability. We show that it is in regimes of large‐scale subsidence that the model results (1) differ the most in climate change and (2) disagree the most with observations in the current climate (most models underestimate the interannual sensitivity of clouds albedo to a change in temperature). This suggests that the simulation of the sensitivity of marine boundary layer clouds to changing environmental conditions constitutes, currently, the main source of uncertainty in tropical cloud feedbacks simulated by general circulation models.
The Brewer reference triad
Authors: Fioletov V. E. , Kerr J. B. , McElroy C. T. , Wardle D. I. , Savastiouk V. , Grajnar T. S.
Published: October 2005

It has been more than 20 years since the Brewer reference triad was established by Environment Canada at Toronto. The triad serves as a reference for traveling standard instruments that are used to calibrate Brewer spectrophotometers around the world. The members of the triad are calibrated on a regular basis at Mauna Loa, Hawaii. Regular tests made with an internal quartz halogen lamp make it possible to track the instrument response between the calibrations. A new analysis of available column ozone data records indicates that the uncertainty in the daily values derived from each instrument is approximately 0.6%. The random errors of individual observations are within ±1% for 90% of all measurements. Sources of potential errors in the individual Brewer measurements as well as quality control tools are also discussed.
Ship‐based liquid water path estimates in marine stratocumulus
Authors: Zuidema Paquita , Westwater Edgeworth R. , Fairall Chris , Hazen Duane
Published: October 2005

We examine liquid water paths (LWPs) derived from ship‐based microwave radiometer brightness temperature (Tb) measurements collected within southeastern Pacific stratocumulus at 20°S, 85°W in October 2001. The boundary layer was typically well mixed and overcast. Three gaseous absorption models and two liquid dielectric models are evaluated. Total differences in retrieved LWP attributable to microwave absorption model differences are 10–25 g m−2, increasing with LWP. The most recent models produce the lowest LWPs. Most of the differences in the retrieved LWPs are caused by differences in the gaseous absorption models. Liquid dielectric model differences generate LWP differences of ∼6% of the total LWP. Radiosonde‐calculated Tb using the most recent gaseous absorption model compare best to Tb measurements. The remaining LWP uncertainty due to model uncertainty is estimated at 6 g m−2. The pre‐1995 gaseous and liquid absorption models in combination produce LWPs that exceed the calculated adiabatic values. For the 6‐day best estimate LWP time series, the clouds attained LWPs close to the theoretical adiabatic limit for LWPs up to 150 g m−2, decreasing to ∼85% for LWPs of ∼250 g m−2. Such deductions also depend upon how the cloud boundaries, to which the adiabatic calculation is sensitive, are determined. Light drizzle, as inferred from cloud radar reflectivitiy measurements, is common even at low LWPs, but heavy drizzle (radar reflectivities >0 dBZ, equivalent to a cloud base drizzle rate of ∼2 mm d−1) is much less frequent, occurring <10% of the time even for LWPs of 200 g m−2.
Influence of forest clear‐cutting on the thermal and hydrological regime of the active layer near Yakutsk, eastern Siberia
Authors: Iwahana Go , Machimura Takashi , Kobayashi Yoshikazu , Fedorov Alexander N. , Konstantinov Pavel Y. , Fukuda Masami
Published: October 2005

Thermal and hydrological conditions in the active layer were investigated at a mature larch forest and an experimental cutover, to clarify the characteristics of heat and water budget in the active layer and to assess the influence of clear‐cutting on permafrost and active layer conditions. Clear‐cutting enhanced ground thawing and the difference in the active layer thickness between the forest and the cutover after 1 year was 14 cm. The soil water content drastically decreased at the forest, while that at the cutover was retained during the first thaw season after clear‐cutting. Although the ground heat flux continued to increase at the cutover (the difference in the total amounts between sites from May to August were 44 and 69 MJ/m2 in 1 year and 2 years after the clear‐cutting, respectively) marked changes in the active layer conditions were limited only to the first thaw season. The correspondent differences in the active layer thickness between the sites were 16 and 14 cm in 2 years and 3 years, respectively. Further increases in the maximum thaw depth at the cutover site were inhibited by the thermal inertial effect of the larger amount of ice in the second spring after disturbance. This suggests a self‐retention mechanism of the active layer thickness after forest disturbance in this continuous permafrost zone.
Modeling of carbon cycling and biogeochemical changes during injection and recovery of reclaimed water at Bolivar, South Australia
Authors: Greskowiak Janek , Prommer Henning , Vanderzalm Joanne , Pavelic Paul , Dillon Peter
Published: October 2005

Managed aquifer recharge is an increasingly popular technique to secure and enhance water supplies. Among a range of recharging techniques, single‐well aquifer storage and recovery (ASR) is becoming a common option to either augment drinking water supplies or facilitate reuse of reclaimed water. For the present study a conceptual biogeochemical model for reclaimed water ASR was developed and incorporated into an existing reactive multicomponent transport model. The conceptual and numerical model for carbon cycling includes various forms of organic and inorganic carbon and several reactive processes that transfer carbon within and across different phases. The major geochemical processes considered in the model were microbially mediated redox reactions, driven by the mineralization of organic carbon, mineral dissolution/precipitation, and ion exchange. The numerical model was tested and applied for the analysis of observed data collected during an ASR field experiment at Bolivar, South Australia. The model simulation of this experiment provides a consistent interpretation of the observed hydrochemical changes. The results suggest that during the storage phase, dynamic changes in bacterial mass have a significant influence on the local geochemistry in the vicinity of the injection/extraction well. Farther away from the injection/extraction well, breakthrough of cations is shown to be strongly affected by exchange reactions and, in the case of calcium, by calcite dissolution.
Solutions of the massive SU(N) Yang–Mills equations by harmonic maps
Authors: Wospakrik H. J.
Published: October 2005

We consider classical static solutions of the pure massive SU(N) Yang–Mills field equations in (3+1)-dimensional space–time. By applying harmonic map ansatz, constructed from the harmonic maps S2→CPN−1, we construct some bounded spherically symmetric solutions having finite energies for N=2, 3, and 4 cases.
An H-theorem for the general relativistic Ornstein-Uhlenbeck process
Authors: Rigotti M. , Debbasch F.
Published: October 2005

We construct conditional entropy four-currents for the general relativistic Ornstein-Uhlenbeck process and we prove that the four-divergences of these currents are always non-negative. This H-theorem is then discussed in detail. In particular, the theorem is valid in any Lorentzian space-time, even those presenting well-known chronological violations.
A new high-temperature multinuclear-magnetic-resonance probe and the self-diffusion of light and heavy water in sub- and supercritical conditions
Authors: Yoshida Ken , Wakai Chihiro , Matubayasi Nobuyuki , Nakahara Masaru
Published: October 2005

A high-resolution nuclear-magnetic-resonance probe (500MHz for H1) has been developed for multinuclear pulsed-field-gradient spin-echo diffusion measurements at high temperatures up to 400°C. The convection effect on the self-diffusion measurement is minimized by achieving the homogeneous temperature distributions of ±1 and ±2°C, respectively, at 250 and 400°C. The high temperature homogeneity is attained by using the solid-state heating system composed of a ceramic (AlN) with high thermal conductivity comparable with that of metal aluminium. The self-diffusion coefficients D for light (H21O) and heavy (H22O) water are distinguishably measured at subcritical temperatures of 30–350°C with intervals of 10–25°C on the liquid-vapor coexisting curve and at a supercritical temperature of 400°C as a function of water density between 0.071 and 0.251g∕cm3. The D value obtained for H21O is 10%–20% smaller than those previously reported because of the absence of the convection effect. At 400°C, the D value for H21O is increased by a factor of 3.7 as the water density is reduced from 0.251to0.071g∕cm3. The isotope ratio D(H21O)∕D(H22O) decreases from 1.23 to ∼1.0 as the temperature increases from 30to400°C. The linear hydrodynamic relationship between the self-diffusion coefficient divided by the temperature and the inverse viscosity does not hold. The effective hydrodynamic radius of water is not constant but increases with the temperature elevation in subcritical water.
Coarse-grained free-energy-functional treatment of quasistatic multiscale processes in heterogeneous materials
Authors: Zhou H. , Feng R. , Diestler D. J. , Zeng X. C.
Published: October 2005

A new treatment of quasistatic (reversible) multiscale processes in heterogeneous materials at nonzero temperature is presented. The system is coarse grained by means of a finite-element mesh. The coarse-grained free-energy functional (of the positions of the nodes of the mesh) appropriate to the thermodynamic-state variables controlled in the relevant process is minimized. Tests of the new procedure on a Lennard-Jonesium crystal yield thermomechanical properties in good agreement with the “exact” atomistic results.
A regularized and renormalized electrostatic coupling Hamiltonian for hybrid quantum-mechanical–molecular-mechanical calculations
Authors: Biswas P. K. , Gogonea V.
Published: October 2005

We describe a regularized and renormalized electrostatic coupling Hamiltonian for hybrid quantum-mechanical (QM)–molecular-mechanical (MM) calculations. To remedy the nonphysical QM/MM Coulomb interaction at short distances arising from a point electrostatic potential (ESP) charge of the MM atom and also to accommodate the effect of polarized MM atom in the coupling Hamiltonian, we propose a partial-wave expansion of the ESP charge and describe the effect of a s-wave expansion, extended over the covalent radius rc, of the MM atom. The resulting potential describes that, at short distances, large scale cancellation of Coulomb interaction arises intrinsically from the localized expansion of the MM point charge and the potential self-consistently reduces to 1∕rc at zero distance providing a renormalization to the Coulomb energy near interatomic separations. Employing this renormalized Hamiltonian, we developed an interface between the Car-Parrinello molecular-dynamics program and the classical molecular-dynamics simulation program Groningen machine for chemical simulations. With this hybrid code we performed QM/MM calculations on water dimer, imidazole carbon monoxide (CO) complex, and imidazole-heme-CO complex with CO interacting with another imidazole. The QM/MM results are in excellent agreement with experimental data for the geometry of these complexes and other computational data found in literature.
Efficient exact exchange approximations in density-functional theory
Authors: Heßelmann A. , Manby F. R.
Published: October 2005

Two approaches to approximate the Slater potential component of local exact exchange of density-functional theory are investigated. The first approach employs density fitting of the electrostatic potential integrals over two occupied orbitals and the other approach approximates the “exact” Slater potential with the potential derived from the Becke-Roussel [Phys. Rev. A. 39, 3761 (1989)] model of the exchange hole. In both cases significant time savings can be achieved for larger systems compared to the calculation of the numerical Slater potential. It is then analyzed how well the orbitals obtained from the various total exchange potentials reproduce Hartree-Fock energies and molecular properties. A large range of atoms and small molecules has been utilized, including the three DNA bases adenine, thymine, and cytosine.
Quantum chemical studies on polythiophenes containing heterocyclic substituents: Effect of structure on the band gap
Authors: Radhakrishnan S. , Parthasarathi R. , Subramanian V. , Somanathan N.
Published: October 2005

Color tuning by the tailoring of substituents at the 3-position of thiophene is very encouraging, and comparative experimental and theoretical studies proved to be powerful in the search for a suitable design for the above. Since the novel polythiophene-based materials substituted with five-membered/six-membered ring containing sulphur and nitrogen at different positions are proven to be potential candidates for electron-transporting hole blocking functions, the structure-property relationship of these systems have been focused in the present study. Molecular-orbital calculations are applied to obtain the optimized geometries and band gaps of the thiophene oligomers. An oligomeric approach has been implemented for calculating the band gaps, and the theoretically obtained band gaps for the different model compounds are compared. Density-functional theory B3LYP∕6-31G* predicted band-gap values are compared with the experimental band gaps obtained from optical-absorption edge. The predicted values show little deviations from experimental band gaps, but the trend in band gap is found to be the same in experimental and theoretical results in most of the cases. Hence, this study illustrates the usefulness of quantum-mechanical calculations in understanding the effects of various structural parameters on optical band gap.
A theoretical study of molecular conduction. II. A Hartree-Fock approach to transmission probability
Authors: Shimazaki Tomomi , Maruyama Hitoshi , Asai Yoshihiro , Yamashita Koichi
Published: October 2005

In this paper, we discuss molecular conductivity based on Green’s function methods. In our calculations, we adopted the self-energy formalism to accommodate semi-infinite electrodes connected to a molecule, and the self-energy was obtained from the surface Green’s function of the electrodes. We adopted the formalism of the surface Green’s function derived by Sanvito et al. [Phys. Rev. B 59, 11936 (1999)] and Krstic et al. [Phys. Rev. B 66, 205319 (2002)], and although their formalisms for the surface Green’s function were different, we were able to demonstrate that these formalisms are mathematically identical. We analyzed the electron transmission probability by using the spectrum expression of Green’s function, instead of using the inverse matrix of the effective Hamiltonian that includes an isolated molecule and the electrodes. Finally, we calculated the transmission probability of benzenedithiol based on the Hartree-Fock method and analyzed the disappearance of the transmission probability due to the orbital interference.
New constraints upon the electron-electron repulsion energy functional of the one-electron reduced density matrix
Authors: Cioslowski Jerzy
Published: October 2005

Three strict constraints upon the electron-electron repulsion energy functional of the one-electron reduced density matrix (the 1-matrix) are obtained by combining its invariance and stationary properties with the extended Koopmans’ theorem. The constraints relate the quantities derived from the functional pertaining to an N-electron system with those of its (N−1)-electron congener. Together with the N-representability requirement for the 1-matrix of the congener, identities involving the electron-electron repulsion energies of the two systems and their derivatives with respect to the 1-matrices seriously narrow down the choices for potential approximate density-matrix functionals. This fact is well illustrated in the case of two-electron systems, where the validity of the new constraints is confirmed and found to originate from a nontrivial cancellation among different terms. Thus, the constraints provide a new tool for the construction and testing of new functionals that complements the previously known conditions such as the reproduction of the homogeneous gas energies and momentum distributions, convexity, and the N-representability of the associated 2-matrices.
Search for memory effects in methane hydrate: Structure of water before hydrate formation and after hydrate decomposition
Authors: Buchanan Piers , Soper Alan K. , Thompson Helen , Westacott Robin E. , Creek Jefferson L. , Hobson Greg , Koh Carolyn A.
Published: October 2005

Neutron diffraction with H∕D isotope substitution has been used to study the formation and decomposition of the methane clathrate hydrate. Using this atomistic technique coupled with simultaneous gas consumption measurements, we have successfully tracked the formation of the sI methane hydrate from a water/gas mixture and then the subsequent decomposition of the hydrate from initiation to completion. These studies demonstrate that the application of neutron diffraction with simultaneous gas consumption measurements provides a powerful method for studying the clathrate hydrate crystal growth and decomposition. We have also used neutron diffraction to examine the water structure before the hydrate growth and after the hydrate decomposition. From the neutron-scattering curves and the empirical potential structure refinement analysis of the data, we find that there is no significant difference between the structure of water before the hydrate formation and the structure of water after the hydrate decomposition. Nor is there any significant change to the methane hydration shell. These results are discussed in the context of widely held views on the existence of memory effects after the hydrate decomposition.
Caging and mosaic length scales in plaquette spin models of glasses
Authors: Jack Robert L. , Garrahan Juan P.
Published: October 2005

We consider two systems of Ising spins with plaquette interactions. They are simple models of glasses which have dual representations as kinetically constrained systems. These models allow an explicit analysis using the mosaic, or entropic droplet, approach of the random first-order transition theory of the glass transition. We show that the low-temperature states of these systems resemble glassy mosaic states, despite the fact that excitations are localized and that there are no static singularities. By means of finite-size thermodynamics we study a generalized caging effect whereby the system is frozen on short length scales, but free at larger length scales. We find that the freezing length scales obtained from statics coincide with those relevant to dynamic correlations, as expected in the mosaic view. The simple nucleation arguments of the mosaic approach, however, do not give the correct relation between freezing lengths and relaxation times, as they do not capture the transition states for relaxation. We discuss how these results make a connection between the mosaic and the dynamic facilitation views of glass formers.
Theoretical studies on magnetic circular dichroism by the finite perturbation method with relativistic corrections
Authors: Honda Y. , Hada M. , Ehara M. , Nakatsuji H. , Michl J.
Published: October 2005

A theoretical method for calculating magnetic circular dichroism (MCD) of molecules is presented. We examined the numerical accuracy and the stability of the finite perturbation (FP) method and the sum-over-state (SOS) perturbation method. The relativistic effects are shown to be important for the MCD spectra of molecules containing heavy elements. Calculations using the FP and the SOS methods were carried out for ethylene, para- and ortho-benzoquinone, showing that the FP method is superior to the SOS method, as expected. The relativistic effect was examined using the second-order Douglas-Kroll Hamiltonians for the halogen molecules F2, Cl2, Br2, and I2. The Faraday terms of I2 and Br2 were strongly affected by the relativistic effects, while the effect was negligible for Cl2 and F2.
Comment on “The effect of density on the properties of short chain fluids” [J. Chem. Phys. 122, 094906 (2005)]
Authors: Taylor Mark P.
Published: October 2005

In a recent work [J. Chem. Phys.122, 094906 (2005)], Porter and Lipson present a Born-Green-Yvon integral equation approach for computing the intramolecular distribution functions of a flexible interaction-site chain in a monomeric solvent. Although this Born-Green-Yvon construction appears to work for a hard-sphere chain-in-solvent system, here we show that the approach yields quantitatively incorrect results for the square-well chain-in-solvent system.
Reply to “Comment on ‘The effect of density on the properties of short chain fluids’” [J. Chem. Phys. 123, 167101 (2005)]
Authors: Porter J. A. , Lipson J. E. G.
Published: October 2005

In this Reply, we respond to the issue raised in Taylor’s Comment [J. Chem. Phys.123, 167101 (2005), preceding paper] on our previous article [J. A. Porter and J. E. G. Lipson, J. Chem. Phys.122, 094906 (2005)] and show that the predictions of the Born-Green-Yvon theory are in qualitative agreement with simulation trends for all chain lengths studied. In addition, we comment on Taylor’s simulation results and discuss why the points raised in Taylor’s Comment do not affect the conclusions reached in our earlier article.