bluuebunny/crossref_metadata_2025_split huggingface dataset:
How does the free complement wave function become accurate and exact finally for the hydrogen atom starting from the Slater and Gaussian initial functions and for the helium atom on the cusp conditions?
Authors: Nakatsuji Hiroshi , Nakashima Hiroyuki 
Published: March 2009

AbstractThe free complement (FC) method, or the free iterative‐complement‐interaction (ICI) method, for generating the exact wave function from an approximate initial wave function has been applied to the hydrogen atom starting from the Slater and Gaussian functions for comparison. The process of improvement was followed by checking the wave function itself and other quantities that have definite exact values. Because the exact wave function is simple in this case, we could make clear analyses for many aspects of the wave function. We examined the energy, the wave function itself, the wave function error, the H‐square error, the local energy near the nucleus, and the cusp. Both the Slater and Gaussian functions gave similar convergence rates to the exact function with respect to the order of the FC method, but the number of complement functions at a particular order is three times larger for the Gaussian case than for the Slater case. Although the cusp value of the Gaussian initial function is zero, it grows as the FC calculation proceeds and finally becomes essentially exact at convergence. The same was true for all the quantities studied here, irrespective of the type of the initial wave function. For the helium atom, the cusp conditions including the electron–electron cusp were also examined with the FC wave function calculated before and shown to converge to the exact values. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Dual‐level hierarchical scheme for linear‐scaling divide‐and‐conquer correlation theory
Authors: Kobayashi Masato , Nakai Hiromi 
Published: March 2009

AbstractA dual‐level hierarchical scheme for the linear‐scaling divide‐and‐conquer (DC)‐based correlation theory is presented as a combination of dual‐buffer and dual‐basis approaches. Although the dual‐basis approach has been well developed, the dual‐buffer approach is specific for the DC correlation method and based on the different interaction lengths between the Hartree–Fock and correlation methods. This study performs numerical assessments of the dual‐buffer DC‐MP2 (second‐order Møller–Plesset perturbation) systematically. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Ab initio QM/MM excited‐state molecular dynamics study of coumarin 151 in water solution
Authors: Kina Daisuke , Arora Pooja , Nakayama Akira , Noro Takeshi , Gordon Mark S. , Taketsugu Tetsuya 
Published: March 2009

AbstractAb initio molecular dynamics (AIMD) simulations are performed to investigate the excited state dynamics of coumarin 151 (C151) in the gas phase and in water solution at the CASSCF level of theory with segmented DZP basis sets, where in the latter case effective fragment potentials (EFP) are used. The dipole moment of an isolated C151 molecule increases considerably upon electronic vertical excitation, from 5.0 D (S0 state) to 11.1 D (S1 state). Two equilibrium structures have been identified in the S1 state, i.e., a charge‐transfer state with a planar amino group and a deformed structure of the six‐membered ring with the carbonyl group, and a structure that is similar to the S0 equilibrium structure. In AIMD simulations for an isolated C151 molecule (presumably similar to dynamics in nonpolar solvents), C151 decays from S1 to S0 via a crossing point of the charge‐transfer state in some trajectories, while in the AIMD simulations for C151‐EFP (including solvent), the S1 and S0 energies show an almost parallel energy variation with structural changes, and no crossing point is observed. This result is in good agreement with the experimental observation. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Mass spectrometric study of peptides secreted by the skin glands of the brown frog Rana arvalis from the Moscow region
Authors: Samgina T. Yu. , Artemenko K. A. , Gorshkov V. A. , Ogourtsov S. V. , Zubarev R. A. , Lebedev A. T. 
Published: March 2009

AbstractA high‐performance liquid chromatography nano‐electrospray ionization Fourier transform mass spectrometry (HPLC/nanoESI‐FTMS) approach involving recording of collision‐activated dissociation (CAD) and electron‐capture dissociation (ECD) spectra of an intact sample and two its modifications after performic oxidation and reduction followed by carboxamidomethylation helps to establish peptide profiles in the crude secretion of frog species at mid‐throughput level, including de novo sequencing. The proposed derivatization procedures allow increasing of the general sequence coverage in the backbone, providing complementary information and, what is more important, reveal the amino acid sequence in the cystine ring (‘rana box’). Thus purely mass spectrometric efficient sequencing becomes possible for longer than usual proteolytic peptides.Seventeen peptides belonging to four known families were identified in the secretion of the European brown frog Rana arvalis inhabiting the Moscow region in Russia. Ranatuerins, considered previously a unique feature of the North American species, as well as a new melittin‐related peptide, are worth special mention. The developed approach was previously successfully used for the identification of peptides in the skin secretion of the Caucasian green frog Rana ridibunda. Copyright © 2009 John Wiley & Sons, Ltd.
Importance of using highly pure internal standards for successful liquid chromatography/tandem mass spectrometric bioanalytical assays
Authors: Bergeron Annik , Furtado Milton , Garofolo Fabio 
Published: March 2009

AbstractInternal standards (IS) with similar physicochemical properties to the analyte provide multiple advantages in liquid chromatography/tandem mass spectrometric (LC/MS/MS) bioanalytical methods such as: reduction of the analysis run time, improvement in the intra‐injection reproducibility, impact reduction of matrix and ionization effects. However, it is important to evaluate the purity of the IS prior to their use. Indeed, a minor impurity in the IS may lead to an important issue during bioanalytical method development. Stable labelled internal standards are usually appropriate IS for bioanalysis. The use of oxycodone‐D3, ursodiol‐D5 and atovaquone‐D4 as internal standards in three different bioanalytical methods was evaluated. During oxycodone, oxymorphone and noroxycodone simultaneous quantification method development, oxymorphone was identified as a contaminant in oxycodone‐D3. Since the limit of quantification for oxymorphone was very low (10 pg/mL), the presence of an even low percentage of oxymorphone in oxycodone‐D3 leads to the change of the stable labelled IS for an analogue, ethylmorphine. 23‐Nordeoxycholic acid was preferred to ursodiol‐D5 as internal standard for the ursodiol, tauroursodiol and glycoursodiol simultaneous quantification method. Indeed, more than 7% of ursodiol was identified in the ursodiol‐D5 which could not be bypassed by decreasing the IS concentration without compromising the linearity. An atovaquone‐D4 reference standard revealed the non‐negligible presence of atovaquone‐D5 to atovaquone‐D8 that has a large impact on the method validation. Therefore, atovaquone‐D4 was sent for recertification since its isotopic purity was found to be much less than the isotopic purity mentioned on its certificate of analysis. Consequently, during bioanalytical method development, the purity of the IS should be scrutinized. Copyright © 2009 John Wiley & Sons, Ltd.
Assessment of in situ thermal treatment for chlorinated organic source zones
Authors: Truex Michael J. , Gillie James M. , Powers Jefferey G. , Lynch Kira P. 
Published: March 2009

AbstractThe East Gate Disposal Yard (EGDY) at Fort Lewis is the source of a large trichloroethene (TCE) plume at this military installation. Source reduction using thermal treatment was applied using electrical resistance heating. A total of about 5,800 kg of TCE‐equivalent volatile organic compounds (VOCs; TCE and dichloroethene) was extracted during thermal treatment of the three zones selected for source reduction. Pretreatment groundwater TCE concentrations were measured up to 100 ppm. Posttreatment groundwater TCE concentrations within the treatment zones averaged less than 100 ppb. Posttreatment soil TCE concentrations decreased by over 96 percent compared to pretreatment soil concentrations. The overall contaminant flux from EGDY was reduced by an estimated 60 to 90 percent by the source reduction effort. The traditional and new techniques for site characterization and remediation performance monitoring applied at EGDY provide insight for installing, operating, monitoring, and assessing thermal treatment. © 2009 Wiley Periodicals, Inc.
Performing contaminant mass balances for remedy assessments
Authors: Gibbs James T. , Santillan Javier 
Published: March 2009

AbstractContaminant mass‐balance assessments are useful tools to help quantify various mass transport and removal mechanisms that may be active in a remedial system setting. This article presents the basics of performing a mass balance and illustrates the utility of using the information derived to support project management decisions. It is important to understand the partitioning of contaminant mass into various environmental media and physical forms, as well as the relationships among the partitions. Contaminant partitioning tends toward an equilibrium state, so natural or engineered mass transfer into or out of one partition will affect the others. Mass balances are exercises that quantify, to the extent possible, the contaminant mass in the various environmental partitions and the transfer and transformation processes that affect contaminant distribution. Understanding mass partitioning and transfer mechanisms helps remediation practitioners to engineer and optimize those mechanisms that contribute to risk reduction at a contaminated site. Such knowledge can inform risk managers when natural mechanisms may dominate engineered approaches and help identify uncertainties in contaminant fate and transport. © 2009 Wiley Periodicals, Inc.
Investigation of NAPL transport through a model sand cap during ebullition
Authors: McLinn Eugene L. , Stolzenburg Thomas R. 
Published: March 2009

AbstractNonaqueous‐phase liquid (NAPL) migration from sediments to the surface of water bodies has been reported frequently at sites with sediments contaminated with NAPLs, such as coal tar and creosote. Commonly, transport of NAPL from sediment is facilitated by gas ebullition caused by anaerobic biodegradation of organic matter in the sediment. A remedy often specified for these sites is a sand cap, and sand caps amended with sorbent materials (such as organoclays) are being pilot‐tested. This article discusses a laboratory study to assess the effectiveness of a sand layer for controlling NAPL migration. The study used a test column composed of a Plexiglas tube containing a tar source that was buried beneath a 30‐cm‐thick layer of fine sand. Water was added to the column until 5 cm of standing water covered the sand layer. To simulate ebullition, air was injected into the base of the sand column at approximately 200 mL/min. It was observed that the gas and NAPL migrated primarily through channels and fractures in the sand, and was not filtered through a network of stable pores. Tar migrated through the sand layer in 12 hours and accumulated on the water surface for several hours before losing its buoyancy and settling back down to the sand surface. After ending the tar migration experiment, the test column was frozen to preserve structures in the sand. The study showed that the tar migrated through the simulated sand cap in small (2‐mm) channels only a few sand grains thick. The results of this laboratory work call into question the effectiveness of sand caps for controlling NAPL migration from sediment in the presence of ebullition. © 2009 Wiley Periodicals, Inc.
Passive to active tie‐in for soil gas surveys: Improved technique for source‐area, spatial variability, remediation‐monitoring, and vapor‐intrusion assessment
Authors: Odencrantz Joseph E. , O'Neill Harry 
Published: March 2009

AbstractThe mass‐to‐concentration tie‐in (MtoC Tie‐In) correlates passive soil gas (PSG) data in mass to active soil gas data in concentration determined by the US EPA Method TO‐17 or TO‐15. Passive soil gas surveys consist of rapid deployment of hydrophobic sorbents (dozens to several hundred locations typically installed in one day) to a depth of six inches to three feet in a grid pattern with exposure in the field from three days to two weeks to target a wide variety of organic compounds. A power function is used on a compound‐to‐compound basis to correlate spatially varying mass (nanograms) from selected locations within a passive soil gas survey to concentration (µg/m3) at those same locations. The correlation from selected PSG locations is applied to the remainder of the PSG grid. The MtoC Tie‐In correlations provide added value to a PSG survey, with the PSG data then used to estimate risk throughout the limits of the investigation for quantitative assessment.The results from a site in northern California show the MtoC Tie‐In correlations for both benzene and total petroleum hydrocarbons (TPH). The correlations are applied on a compound‐to‐compound basis to the remaining locations in the PSG grid to provide an estimate of concentration that can be used for comparison to risk/screening levels or fate‐and‐transport diagnostic tools (partitioning equations, solubility laws, etc.). An example of how the correlations are applied is presented in tabular form. The results from a chlorinated solvent survey show the MtoC Tie‐In correlation from a site in Maryland for tetrachloroethene (PCE). In this instance, there was a near‐perfect relationship between the PSG mass and the active soil gas concentration (R2 value of 1). The concentration estimated throughout a PSG grid enables a vast new realm of interpretive power at sites. Several other sites are discussed, including an example application for groundwater. © 2009 Wiley Periodicals, Inc.
LEHR superfund stormwater runoff and putah creek mercury issues
Authors: Lee G. Fred , Jones‐Lee Anne 
Published: March 2009

AbstractStormwater runoff from the University of California, Davis/U.S. Department of Energy Laboratory for Energy‐Related Health Research (UCD/US DOE LEHR) Superfund site located on the University of California campus in Davis, California, has been found to contain over 500 ng/L of total recoverable mercury, which is about ten times the California Toxics Rule criterion. This stormwater runoff is discharged to Putah Creek, which is Clean Water Act Section 303(d) listed as impaired for excessive mercury bioaccumulation in edible fish. A discussion is presented on the potential impact of the mercury in stormwater runoff from LEHR leading to excessive bioaccumulation of mercury in Putah Creek fish. The mercury in the stormwater runoff is derived from former flooding of the soils near the creek, which contains mercury derived from abandoned upstream mercury mines located in the Coast Range Vaca Hills to the west of LEHR. The implications of this situation for implementing a Total Maximum Daily Load (TMDL) to control mercury in stormwater runoff to Putah Creek are presented. © 2009 Wiley Periodicals, Inc.
New statistical approaches for anomaly detection
Authors: Callegari Christian , Giordano Stefano , Pagano Michele 
Published: March 2009

AbstractComputer security is a growing problem. Over the last years, the number and variety of security attacks in IP‐ based network infrastructures have increasingly grown, leading to the need of developing new security architectures. In this scenario, the use of intrusion detection systems (IDSs) has emerged as a key element, since it permits to tackle security threats by masquerader, misfeasor, and clandestine users. In this paper, we address the problem considering some new statistical techniques for detecting network anomalies. In more detail, the paper discusses the use of several statistical models to characterize the normal behavior of the network traffic running over TCP, so that anomalies can be revealed as significant deviations from such behavior. Namely, our proposal is based on the use of Markov chains, co‐ occurrence matrices, and compression algorithms, for modeling the TCP connections, in terms of statistical analysis of some of the packet header fields. The performance analysis, presented in this paper, demonstrates the effectiveness of the proposed methods. Copyright © 2009 John Wiley & Sons, Ltd.
Regulatory focus and new venture performance: A study of entrepreneurial opportunity exploitation under conditions of risk versus uncertainty
Authors: Hmieleski Keith M. , Baron Robert A. 
Published: March 2009

AbstractResearch on cognitive fit suggests that entrepreneurs will be most successful at leading their firms when approaching the entrepreneurial process through the self‐regulatory mode that most closely matches the requirements of their environment and its accompanying perspective on the nature of entrepreneurial opportunities. Consistent with the discovery view of entrepreneurial opportunities, it is suggested that a prevention focus will be the most effective self‐regulatory mode for entrepreneurs leading their firms within stable industry environments, which are characterized by risk. Building from the creation view of entrepreneurial opportunities, it is argued that a promotion focus will be the most effective self‐regulatory mode for entrepreneurs leading their firms within dynamic industry environments, which are characterized by uncertainty. These arguments are tested using a national (United States) random sample of 201 lead entrepreneurs. The findings indicate that in dynamic environments, entrepreneurs' promotion focus is positively associated with venture performance (i.e., lagged measures of revenue and employment growth), while entrepreneurs' prevention focus is negatively related to performance in such environments. In both cases, these effects are found to be fully mediated by deviation from firms' original business concepts. In stable environments, however, no significant relationships between entrepreneurs' promotion or prevention focus and new venture performance were observed. These results suggest that low cognitive fit (a mismatch between entrepreneurs' mode of self‐regulation and the decision‐making context in which they operate) is more damaging in dynamic environments (i.e., a context of uncertainty) than in stable environments (i.e., a context of risk). Copyright © 2009 Strategic Management Society.
Niche construction: The process of opportunity creation in the environment
Authors: Luksha Pavel 
Published: March 2009

AbstractThis article contributes to the emerging theory of opportunity creation by examining how organizations (including entrepreneurial ones) create and transform their niches. Using insights from contemporary evolutionary theory, the article classifies types of niche construction activities along dimensions of governance and the nature of the strategic actor. It then focuses on mechanisms of niche construction governed by the focal organization or entrepreneur to explain how competitive imperfections can be induced within industries and markets. The central role of communicative strategies in niche construction is emphasized. Copyright © 2009 Strategic Management Society.
Factor payments, resource‐based bargaining, and the creation of firm wealth in technology‐based ventures
Authors: Townsend David M. , Busenitz Lowell W. 
Published: March 2009

AbstractA central tenet of resource‐based logic is that undervalued resources utilized by firms organized to exploit them will produce superior economic performance over the long run. Yet when young technology‐based ventures pursuing new opportunities do not possess full property over these resources, input providers retain the right to bid up factor prices to match each resource's marginal productivity. In response to these limitations in extant resource‐based logic, we apply and extend Lippman and Rumelt's full payments and bargaining perspectives and propose an alternative method by which entrepreneurs can generate firm wealth through the unique bundling of cospecialized resources. Both theoretical implications and directions for future research are discussed as well. Copyright © 2009 Strategic Management Society.
Exercising entrepreneurial opportunities: The role of information‐gathering and information‐processing capabilities of the firm
Authors: Sleptsov Alexander , Anand Jaideep 
Published: March 2009

AbstractIn this article, we study two capabilities that influence firms' effectiveness in exercising entrepreneurial opportunities: information‐gathering and information‐processing capability. We argue that their effects are not always positive or symmetrical. When the firm's information‐processing capability is low, high levels of its information‐gathering capability may result in lower effectiveness because of managerial cognitive overload. The effects of high information‐processing capability are more nuanced and depend on whether the firm's information processing has experiential or cognitive character. Our analysis offers a counterintuitive insight: the firm may fail to exercise entrepreneurial opportunities effectively not only when it has low levels of information capabilities, but also when its levels are high but unbalanced. Copyright © 2009 Strategic Management Society.
A Bayesian approach to joint analysis of longitudinal measurements and competing risks failure time data
Authors: Hu Wenhua , Li Gang , Li Ning 
Published: March 2009

AbstractIn this paper, we develop a Bayesian method for joint analysis of longitudinal measurements and competing risks failure time data. The model allows one to analyze the longitudinal outcome with nonignorable missing data induced by multiple types of events, to analyze survival data with dependent censoring for the key event, and to draw inferences on multiple endpoints simultaneously. Compared with the likelihood approach, the Bayesian method has several advantages. It is computationally more tractable for high‐dimensional random effects. It is also convenient to draw inference. Moreover, it provides a means to incorporate prior information that may help to improve estimation accuracy. An illustration is given using a clinical trial data of scleroderma lung disease. The performance of our method is evaluated by simulation studies. Copyright © 2009 John Wiley & Sons, Ltd.
A multivariate CAR model for improving the estimation of relative risks
Authors: Greco Fedele P. , Trivisano Carlo 
Published: March 2009

AbstractDisease mapping studies have been widely performed at univariate level, that is considering only one disease in the estimated models. Nonetheless, simultaneous modelling of different diseases can be a valuable tool both from the epidemiological and from the statistical point of view. In this paper we propose a model for multivariate disease mapping that generalizes the univariate conditional auto‐regressive distribution. The proposed model is proven to be an effective alternative to existing multivariate models, mainly because it overcome some restrictive hypotheses underlying models previously proposed in this context. Model performances are checked via a simulation study and via application to a case study. Copyright © 2009 John Wiley & Sons, Ltd.