bluuebunny/crossref_metadata_2025 huggingface dataset:
Outcome‐directed clinical practice in lumbar spine surgery
Authors: Clapham Lorraine M. , Buckley Julie
Published: July 2002

Outcome audits describe the current level of clinical performance and direct change in clinical practice. The outcome measures used should be not only relevant and easily understood but also available to all interested parties, e.g. patients, clinicians and commissioners of health. The results of audits can be used to set the standard from which clinical practice can be monitored and improved. An expectation of likely outcome also gives the patient the opportunity of being able to make a fully informed choice. This audit using prospective data examines and compares the outcome of surgery for degenerative lumbar spine disease over a two‐year period. The results allow more accurate information to be given to patients, areas of service development to be identified and changes in clinical practice to be made.
Grey literature is a feminist issue: women’s knowledge and the Net
Authors: Malina Danusia , Nutt Diane
Published: July 2002

Throughout its history feminism has produced “grey” literature. This material has played an important part in communicating women’s knowledge(s) and instigating activism. This paper considers the development of grey literature within feminism and its value to feminism, in brief. The key focus of the paper is in the potentials of the Internet as a communication mechanism and for feminist grey literature. Consideration is given to rapidly expanding forms of feminist grey literature on the Internet, and the potentials and concerns raised by this grey medium are discussed. Despite fears raised by some writers about the dangers and difficulties of cyberspace for women, overall this paper is optimistic about the potentials for feminist grey literature. Hence, it is suggested that grey literature on the Net offers global feminist sustenance; potential empowerment; and a means to challenge social inequalities.
arXiv.org: the Los Alamos National Laboratory e‐print server
Authors: McKiernan Gerry
Published: July 2002

Since its creation nearly ten years ago, the Los Alamos National Laboratory (LANL) e‐print service (arXiv.org) has revolutionized scholarly communication within many scientific communities. It has also inspired the development of alternatives to conventional and electronic journal publication in a variety of other disciplines. The LANL e‐print database is also serving as the core collection for two major investigations that seek to enhance access and navigation within and between electronic archives and special collections.
Quality‐controlled subject gateways: definitions, typologies, empirical overview
Authors: Koch Traugott
Published: July 2002

“Quality‐controlled subject gateways” are Internet services which apply a rich set of quality measures to support systematic resource discovery. Considerable manual effort is used to secure a selection of resources which meet quality criteria and to display a rich description of these resources with standards‐based metadata. Regular checking and updating ensure good collection management. A main goal is to provide a high quality of subject access through indexing resources using controlled vocabularies and by offering a deep classification structure for advanced searching and browsing. This article provides an initial empirical overview of existing services of this kind, their approaches and technologies, based on proposed working definitions and typologies of subject gateways.
Sharing tools on newspaper Web sites: an exploratory study
Authors: Erdelez Sanda , Rioux Kevin
Published: July 2002

Many Web sites include buttons or links (sharing tools) that allow users to conveniently share news stories and other information with friends, family and colleagues via e‐mail. This paper reports on an exploratory study of the design and functional features of sharing tools on a sample of 11 US newspaper Web sites. The authors examined the appearance, location, and features of sharing tools that are provided to both senders and recipients. Sample news stories were also “shared” with one of the authors using each of the sharing tools, and data about the appearance and content of these messages were collected. The major findings of the study suggest that on the sampled Web sites: there is lack of standardisation in the visual design and placement of the sharing tools; insufficient information is provided to the user about how to use the tool; information about the security and privacy is absent or incomplete; and many tools cannot be user‐customized, and are not convenient to use.
Should scientific journals be printed? A personal view
Authors: Goodman David
Published: July 2002

Although the widely appreciated advantages of electronic journals in the sciences would indicate that they should be the preferred form of publication, they persist in print as well. The data on the relative use of bound and unbound journals in an academic biology library suggest that almost all of the journals studied are suitable as electronic only; only a very few are reasonable choices in both print and electronic formats. Most scientific articles might be better suited for publication not in journals at all, but rather in a suitable Internet‐based repository.
Use of the Internet for reference services in Malaysian academic libraries
Authors: Abdoulaye Kaba , Majid Shaheen
Published: July 2002

The integration of the Internet has affected all functions of the library, particularly reference services. In the reference department, this integration has led to the utilisation of new tools and methods for providing information to library users. This study investigates the effect of the Internet on reference services in Malaysian academic libraries. The objective of the study was to find out how the integration of the Internet has affected reference professionals and services. The study also investigated respondents’ perceptions of the importance of the Internet in reference work. A total of 40 library professionals working in the reference department of nine Malaysian academic libraries participated in the study. Respondents felt that the Internet has contributed positively to reference work and has enhanced their effectiveness and efficiency. However, a majority of them disagreed that the Internet should completely replace traditional reference tools. Respondents also felt that reference librarians should possess good computing and Internet use skills for providing effective reference services.
Using intellectual assets as a success strategy
Authors: Klaila Davis , Hall Lynne
Published: July 2002

You may be surprised to discover that millions of dollars in revenue are sitting, undiscovered, inside your own organization. Follow the authors as they walk you through different areas of your business to discover the untapped potential of “forgotten” intangible assets that may already exist, including patents, trademarks, licensing arrangements, employee know‐how, infringement protection plans and much more. Learn how to manage these assets to their fullest potential by creating an Intellectual Asset Management Portfolio (I‐AMP). The authors reveal their own five‐step process and then present three case studies (an energy company, a high‐tech manufacturer and a telecom company), which illustrate the remarkable increases in revenue generated by this program. In one case, $1 billion was shifted from the expenditure to the revenue side of the ledger!
The next generation of IC measurement – the digital IC‐landscape
Authors: Edvinsson Leif , Kitts Brendan , Beding Tord
Published: July 2002

A methodology (based on multi‐dimensional scaling and mathematical statistics) is introduced that reduces the high dimensionality of “IC‐differencing components” into a 3‐D dimensional representation – the digital IC‐landscape. Building and maintaining a digital IC‐landscape supports systematically: pedagogical display of IC complexity, migration of IC‐affecting knowledge, exploratory retrieval of high IC‐efficiency, investment planning and forecasting. In this project, 11 companies – with a total of 20‐64 “essential variables” and “free parameters” – have been analyzed and results of the study reported.
Intellectual capital in the new Internet economy – Its meaning, measurement and management for enhancing quality
Authors: Carroll Ray F. , Tansey Richard R.
Published: July 2002

Intellectual capital is the cornerstone of corporate success in the new economy. This article will discuss the meaning, measurement, and management of intellectual capital. It discusses the forces driving the concern about intellectual capital and how one company, Intel Corporation, has been able to manage intellectual capital to achieve market dominance. Unlike Philip Morris, Coca‐Cola or McDonald’s, which earn hundreds of millions year‐in and year‐out from the same product lines, technology companies must constantly reinvent themselves. Intel has managed to do this, but it is the exception.
Some perspectives on intangibles and intellectual capital 2000
Authors: Edvinsson Leif
Published: July 2002

After posing some questions regarding the nature of intellectual capital, the paper explores IC through observing the changes in market dynamics and organizational structure. An IC growth model is discussed which involves visualizing IC, human capital injection, human capital transformation into structural capital, and structural capital injection.
Developing and managing knowledge through intellectual capital statements
Authors: Mouritsen J. , Bukh P.N. , Larsen H.T. , Johansen M.R.
Published: July 2002

On the basis of empirical illustrations from five Danish firms this paper discusses how the objects of intellectual capital statements were constructed. These objects were the activities that defined knowledge management, and the intellectual capital statements monitored these through depicting a particular narrativised strategy for managing knowledge – called a knowledge narrative – and through a monitoring system that reflected the activities set in motion to mobilise the strategy for managing knowledge. Particularly, the paper discusses the idea of knowledge as a narrative. It is suggested that for knowledge to count, it has to be able to produce something. This something is found the value‐to‐the‐user of the products and services.
Intellectual capital and business start‐up success
Authors: Peña Iñaki
Published: July 2002

While start‐up firms create a substantial economic impact on most economies, the failure rate of start‐up firms seems to remain high over time. Few authors have examined the influence of intellectual capital management on business performance, and when it has been examined, the focus has been on large, mature and public companies. The purpose of this study is to analyze the extent to which IC assets are associated with new firm survival and growth. Results from this study suggest that the human capital of the entrepreneur (i.e. education, business experience and level of motivation), organizational capital (i.e. firm capacity to adapt quickly to changes and the ability to implement successful strategies), and relational capital (i.e. development of productive business networks and an immediate access to critical stakeholders) are important intangible assets, which seem to be related positively to venture performance.
Crystal structures of free, IMP‐, and GMP‐bound Escherichia coli hypoxanthine phosphoribosyltransferase
Authors: Guddat Luke W. , Vos Siska , Martin Jennifer L. , Keough Dianne T. , de Jersey John
Published: July 2002

Crystal structures have been determined for free Escherichia coli hypoxanthine phosphoribosyltransferase (HPRT) (2.9 Å resolution) and for the enzyme in complex with the reaction products, inosine 5′‐monophosphate (IMP) and guanosine 5′‐monophosphate (GMP) (2.8 Å resolution). Of the known 6‐oxopurine phosphoribosyltransferase (PRTase) structures, E. coli HPRT is most similar in structure to that of Tritrichomonas foetus HGXPRT, with a rmsd for 150 Cα atoms of 1.0 Å. Comparison of the free and product bound structures shows that the side chain of Phe156 and the polypeptide backbone in this vicinity move to bind IMP or GMP. A nonproline cis peptide bond, also found in some other 6‐oxopurine PRTases, is observed between Leu46 and Arg47 in both the free and complexed structures. For catalysis to occur, the 6‐oxopurine PRTases have a requirement for divalent metal ion, usually Mg2+ in vivo. In the free structure, a Mg2+ is coordinated to the side chains of Glu103 and Asp104. This interaction may be important for stabilization of the enzyme before catalysis. E. coli HPRT is unique among the known 6‐oxopurine PRTases in that it exhibits a marked preference for hypoxanthine as substrate over both xanthine and guanine. The structures suggest that its substrate specificity is due to the modes of binding of the bases. In E. coli HPRT, the carbonyl oxygen of Asp163 would likely form a hydrogen bond with the 2‐exocyclic nitrogen of guanine (in the HPRT‐guanine‐PRib‐PP‐Mg2+ complex). However, hypoxanthine does not have a 2‐exocyclic atom and the HPRT‐IMP structure suggests that hypoxanthine is likely to occupy a different position in the purine‐binding pocket.
Efficient docking of peptides to proteins without prior knowledge of the binding site
Authors: Hetényi Csaba , van der Spoel David
Published: July 2002

Reliability in docking of ligand molecules to proteins or other targets is an important challenge for molecular modeling. Applications of the docking technique include not only prediction of the binding mode of novel drugs, but also other problems like the study of protein‐protein interactions. Here we present a study on the reliability of the results obtained with the popular AutoDock program. We have performed systematical studies to test the ability of AutoDock to reproduce eight different protein/ligand complexes for which the structure was known, without prior knowledge of the binding site. More specifically, we look at factors influencing the accuracy of the final structure, such as the number of torsional degrees of freedom in the ligand. We conclude that the Autodock program package is able to select the correct complexes based on the energy without prior knowledge of the binding site. We named this application blind docking, as the docking algorithm is not able to “see” the binding site but can still find it. The success of blind docking represents an important finding in the era of structural genomics.
Structural basis for cyclodextrins' suppression of human growth hormone aggregation
Authors: Otzen Daniel Erik , Knudsen Benjamin Raerup , Aachmann Finn , Larsen Kim Lambertsen , Wimmer Reinhard
Published: July 2002

Many therapeutic proteins require storage at room temperature for extended periods of time. This can lead to aggregation and loss of function. Cyclodextrins (CDs) have been shown to function as aggregation suppressors for a wide range of proteins. Their potency is often ascribed to their affinity for aromatic amino acids, whose surface exposure would otherwise lead to protein association. However, no detailed structural studies are available. Here we investigate the interactions between human growth hormone (hGH) and different CDs at low pH. Although hGH aggregates readily at pH 2.5 in 1 M NaCl to form amorphous aggregates, the presence of 25 to 50 mM of various β‐CD derivatives is sufficient to completely avoid this. α‐ and γ‐CD are considerably less effective. Stopped‐flow data on the aggregation reaction in the presence of β‐CD are analyzed according to a minimalist association model to yield an apparent hGH‐β‐CD dissociation constant of ∼6 mM. This value is very similar to that obtained by simple fluorescence‐based titration of hGH with β‐CD. Nuclear magnetic resonance studies indicate that β‐CD leads to a more unfolded conformation of hGH at low pH and predominantly binds to the aromatic side‐chains. This indicates that aromatic amino acids are important components of regions of residual structure that may form nuclei for aggregation.
The neuropeptide Y monomer in solution is not folded in the pancreatic‐polypeptide fold
Authors: Bettio Andrea , Dinger Michaela C. , Beck‐Sickinger Annette G.
Published: July 2002

Fluorescence‐labelled analogs of NPY, a 36‐amino acid peptide amide, were synthesized by solid‐phase peptide synthesis and used for fluorescence‐resonance energy transfer studies to investigate the conformation. Energy‐transfer efficiency measurements in different media at the concentration of 10 μM are in agreement with a model of the NPY structure proposed by NMR studies (performed at millimolar concentration) in which the C‐terminal part of the molecule adopts an α‐helical conformation while the N‐terminal part is flexible. According to this model, the α‐helix is stabilized by intermolecular hydrophobic interactions because of the formation of dimers. The decrease of the peptide concentration causes a shift of the dimerization equilibrium toward the monomeric form. Energy‐transfer efficiency measurements performed at lower concentrations do not support the hypothesis of the folding back of the N‐terminal tail onto the C‐terminal α‐helix to yield the so‐called “PP‐fold” conformation. This structure is observed in the crystal structure of avian pancreatic polypeptide, a member of the NPY peptide hormone family, and it has been considered to be the bioactive one. Our results complete the structural characterization of NPY in solution at concentration ranges in which NMR experiments are not feasible. Furthermore, these results open the way to study the conformation of the receptor‐bound ligand.
Characterization of ostrich (Struthio camelus) β‐microseminoprotein (MSP): Ideication of homologous sequences in EST databases and analysis of their evolution during speciation
Authors: Lazure Claude , Villemure Michéle , Gauthier Dany , Naudé Ryno J. , Mbikay Majambu
Published: July 2002

β‐Microseminoprotein, alternatively called prostatic secretory protein of 94 amino acids, is a hydrophilic, unglycosylated, small protein rich in conserved half‐cystine residues. Originally found in human seminal plasma and prostatic fluids, its presence was later shown in numerous secretions and its homologs were described in many vertebrate species. These studies showed that this protein had rapidly evolved, but they failed to unambiguously idey its biological role. Here, we show that a protein isolated from ostrich pituitary gland is closely related to a similar one isolated from chicken serum and that the two are structurally related to the mammalian β‐microseminoprotein. The complete 90–amino acid sequence of the ostrich molecule was established through a combination of automated Edman degradation and matrix‐assisted laser desorption ionization–time of flight (MALDI‐TOF) mass spectrometric procedures, including postsource decay (PSD) and ladder sequencing analyses. This study documents for the first time that β‐microseminoprotein is present in aves. It is also the first report of a C‐terminal amidated form for a member of this protein family and the first in which the disulfide linkages are established. Database searches using the herein‐described amino acid sequence allowed ideication of related proteins in numerous species such as cow, African clawed frog, zebrafish, and Japanese flounder. These small proteins show a strikingly high rate of amino acid substitutions, especially across phyla boundaries. Noticeably, no β‐microseminoprotein–related gene could be found in the recently completed fruit fly genome, indicating that if such a gene exists in arthropods, it must have extensively diverged from the vertebrate ones.
Native‐state conformational dynamics of GART: A regulatory pH‐dependent coil–helix transition examined by electrostatic calculations
Authors: Morikis Dimitrios , Elcock Adrian H. , Jennings Patricia A. , McCammon J. Andrew
Published: July 2002

Glycinamide ribonucleotide transformylase (GART) undergoes a pH‐dependent coil–helix transition with pKa ∼ 7. An α‐helix is formed at high pH spanning 8 residues of a 21‐residue‐long loop, comprising the segment Thr120–His121–Arg122–Gln123–Ala124–Leu125–Glu126–Asn127. To understand the electrostatic nature of this loop–helix, called the activation loop–helix, which leads to the formation and stability of the α‐helix, pKa values of all ionizable residues of GART have been calculated, using Poisson–Boltzmann electrostatic calculations and crystallographic data. Crystallographic structures of high and low pH E70A GART have been used in our analysis. Low pKa values of 5.3, 5.3, 3.9, 1.7, and 4.7 have been calculated for five functionally important histidines, His108, His119, His121, His132, and His137, respectively, using the high pH E70A GART structure. Ten theoretical single and double mutants of the high pH E70A structure have been constructed to idey pairwise interactions of ionizable residues, which have aided in elucidating the multiplicity of electrostatic interactions of the activation loop–helix, and the impact of the activation helix on the catalytic site. Based on our pKa calculations and structural data, we propose that: (1) His121 forms a molecular switch for the coil–helix transition of the activation helix, depending on its protonation state; (2) a strong electrostatic interaction between His132 and His121 is observed, which can be of stabilizing or destabilizing nature for the activation helix, depending on the relative orientation and protonation states of the rings of His121 and His132; (3) electrostatic interactions involving His119 and Arg122 play a role in the stability of the activation helix; and (4) the activation helix contains the helix‐promoting sequence Arg122–Gln123–Ala124–Leu125–Glu126, but its alignment relative to the N and C termini of the helix is not optimal, and is possibly of a destabilizing nature. Finally, we provide electrostatic evidence that the formation and closure of the activation helix create a hydrophobic environment for catalytic‐site residue His108, to facilitate catalysis.
Proteins of circularly permuted sequence present within the same organism: The major serine proteinase inhibitor from Capsicum annuum seeds
Authors: Antcheva Nikolinka , Pintar Alessandro , Patthy András , Simoncsits András , Barta Endre , Tchorbanov Bojidar , Pongor Sándor
Published: July 2002

The major serine proteinase inhibitor from bell pepper (Capsicum annuum, paprika) seeds was isolated, characterized, and sequenced, and its disulfide bond topology was determined. PSI‐1.2 is a 52‐amino‐acid‐long, cysteine‐rich polypeptide that inhibits both trypsin (Ki = 4.6 × 10−9 M) and chymotrypsin (Ki = 1.1 × 10−8 M) and is a circularly permuted member of the potato type II inhibitor family. Mature proteins of this family are produced from precursor proteins containing two to eight repeat units that are proteolytically cleaved within, rather than between, the repeats. In contrast, PSI‐1.2 corresponds to a complete repeat that was predicted as the putative ancestral protein of the potato type II family. To our knowledge, this is the first case in which two proteins related to each other by circular permutation are shown to exist in the same organism and are expressed within the same organ. PSI‐1.2 is not derived from any of the known precursors, and it contains a unique amphiphilic segment in one of its loops. A systematic comparison of the related precursor repeat‐sequences reveals common evolutionary patterns that are in agreement with the ancestral gene‐duplication hypothesis.
Role of conserved residues in structure and stability: Tryptophans of human serum retinol‐binding protein, a model for the lipocalin superfamily
Authors: Greene Lesley H. , Chrysina Evangelia D. , Irons Laurence I. , Papageorgiou Anastassios C. , Acharya K. Ravi , Brew Keith
Published: July 2002

Serum retinol binding protein (RBP) is a member of the lipocalin family, proteins with up‐and‐down β‐barrel folds, low levels of sequence identity, and diverse functions. Although tryptophan 24 of RBP is highly conserved among lipocalins, it does not play a direct role in activity. To determine if Trp24 and other conserved residues have roles in stability and/or folding, we investigated the effects of conservative substitutions for the four tryptophans and some adjacent residues on the structure, stability, and spectroscopic properties of apo‐RBP. Crystal structures of recombinant human apo‐RBP and of a mutant with substitutions for tryptophans 67 and 91 at 1.7 Å and 2.0 Å resolution, respectively, as well as stability measurements, indicate that these relatively exposed tryptophans have little influence on structure or stability. Although Trp105 is largely buried in the wall of the β‐barrel, it can be replaced with minor effects on stability to thermal and chemical unfolding. In contrast, substitutions of three different amino acids for Trp24 or replacement of Arg139, a conserved residue that interacts with Trp24, lead to similar large losses in stability and lower yields of native protein generated by in vitro folding. The results and the coordinated nature of natural substitutions at these sites support the idea that conserved residues in functionally divergent homologs have roles in stabilizing the native relative to misfolded structures. They also establish conditions for studies of the kinetics of folding and unfolding by ideying spectroscopic signals for monitoring the formation of different substructures.
Chemical‐modification rescue assessed by mass spectrometry demonstrates that γ‐thia‐lysine yields the same activity as lysine in aldolase
Authors: Hopkins Christopher E. , O'connor Peter B. , Allen Karen N. , Costello Catherine E. , Tolan Dean R.
Published: July 2002

The role of active site residues in fructose 1,6‐bisphosphate aldolase is investigated by chemical‐modification rescue. An active‐site mutation, K107C, is constructed in a background where the four solvent‐accessible cysteine residues are converted to alanine. The resulting mutant, tetK107C, when reacted with bromoethylamine (BrEA), shows a 40‐fold increase in activity (to 80% that of wild type). Determination of the sites and their degree of modification using electrospray ionization Fourier transform mass spectrometry (ESI‐FTMS) is developed, allowing correlation of activity after chemical modification rescue to the degree of modification. The stoichiometry of the reaction is 2.5 aminoethylations per subunit, as measured by ESI‐FTMS. Protein modification with a double‐labeled mix (1:1) of natural abundance isotope (d0‐BrEA) and 2‐bromoethyl‐1,1,2,2‐d4‐amine hydrobromide (d4‐BrEA), followed by dialysis and trypsin digestion, shows aminoethylated peptides as “twin peptides” separated by four mass units in ESI‐FTMS analysis. Using this detection procedure under nondenaturing (native) conditions, C107 is aminoethylated, whereas the four buried thiols remain unlabeled. Aminoethylation of other residues is observed, and correlates with those peptides containing histidine, methionine, and/or the amino terminus. Quantification of the aminoethylation reaction is achieved by labeling with nondeuterated d0‐BrEA under denaturing conditions following double labeling under native conditions. In addition to complete labeling all five thiols, the intensity of the d0‐BrEA peak for C107 containing peptides increases, and the change in the d0/d4 ratio between native and denaturing conditions shows 82 ± 4.5% aminoethylation at C107. This correlation of modification with the recovered activity, indicates that γ‐thia‐lysine replaces lysine in the catalytic mechanism. Kinetic constants measured for the rescued K107C mutant enzyme with the substrates fructose 1‐phosphate and fructose 1,6‐bisphosphate are consistent with the role of the positively charged lysine binding to the C6‐phosphate. ESI‐FTMS, combined with this double‐labeling procedure, allows precise identification of sites and measurement of degree of protein modification.
Delay of Gratification: Impulsive Choices and Problem Behaviors in Early and Late Adolescence
Authors: Wulfert Edelgard , Block Jennifer A. , Santa Ana Elizabeth , Rodriguez Monica L. , Colsman Melissa
Published: July 2002

ABSTRACT High school students were offered a monetary incentive for participating in research. They were given a choice between a smaller fee immediately or a larger fee one week later. Compared to students who delayed gratification, those who chose the immediate fee showed more self‐regulatory deficits. They showed greater involvement with cigarettes, alcohol, and marijuana, had a poorer self‐concept and underperformed academically. A replication study with middle‐school students and different reward parameters yielded equivalent results. Younger adolescents who chose the immediate monetary incentive showed a similar pattern of problem behaviors as the high school students. The findings indicate that this simple choice‐delay procedure yields an unobtrusive behavioral measure of self‐regulation and offers a developmentally appropriate extension of the delay‐of‐gratification paradigm for use with older children and adolescents.
When a Grandiose Self‐Image Is Threatened: Narcissism and Self‐Concept Clarity as Predictors of Negative Emotions and Aggression Following Ego‐Threat
Authors: Stucke Tanja S. , Sporer Siegfried L.
Published: July 2002

ABSTRACT Two studies examined the relation between narcissism, self‐concept clarity, negative emotions, and aggression based on theoretical assumptions proposed by Baumeister, Smart, and Boden (1996). Narcissism and self‐concept clarity were examined as predictors for anger, depression, and verbal aggression following ego‐threat, which was operationalized by a bogus performance feedback on an intelligence test. The second study also examined the mediating effects of participants' negative emotions to provide an additional explanation for the aggressive reactions after failure. As expected, narcissism and self‐concept clarity were significant predictors of negative emotions and aggression after failure. In accordance with our hypothesis, high narcissists with low self‐concept clarity reacted with anger and aggression after failure, whereas less narcissistic individuals with high self‐concept clarity showed feelings of depression and no aggression. The results also indicated that aggression was always directed toward the source of the ego‐threatening feedback. Additionally, anger and depression could predict the aggressive response after failure but they did not mediate the relation between narcissism, self‐concept clarity, performance feedback, and aggression.
A Test to Detect Within‐family Infectivity when the Whole Epidemic Process is Observed
Authors: Britton Tom
Published: July 2002

An epidemic model for the spread of an infectious disease in a population of families is considered. The score test of the hypothesis that there is no higher infectivity between family members is constructed under the assumption that the epidemic process is observed continuously up to some time t. The score process is a martingale as a function of t and by letting the number of families tend to infinity, a central limit theorem for the process can be proved. The central limit theorem not only justifies a normal approximation of the test statistic—it also suggests a smaller variance estimator than expected.
Existence of Maximum Likelihood Estimates for Multi‐dimensional Exponential Families
Authors: Miao Weiwen , Hahn Marjorie
Published: July 2002

This paper deals with the existence of maximum likelihood estimators for multi‐dimensional exponential families, including curved exponential families. It first gives an algorithm for determining the MLE from the data. Then it establishes that when the parameter set is either open or relatively closed in the natural parameter set, the MLE of the parameter exists in the sense of Hoffmann‐Jorgensen.
Multiple Hypotheses Testing with Weights
Authors: Benjamini Yoav , Hochberg Yosef
Published: July 2002

In this paper we offer a multiplicity of approaches and procedures for multiple testing problems with weights. Some rationale for incorporating weights in multiple hypotheses testing are discussed. Various type‐I error‐rates and different possible formulations are considered, for both the intersection hypothesis testing and the multiple hypotheses testing problems. An optimal per family weighted error‐rate controlling procedure a la Spjotvoll (1972) is obtained. This model serves as a vehicle for demonstrating the different implications of the approaches to weighting. Alternative approach es to that of Holm (1979) for family‐wise error‐rate control with weights are discussed, one involving an alternative procedure for family‐wise error‐rate control, and the other involving the control of a weighted family‐wise error‐rate. Extensions and modifications of the procedures based on Simes (1986) are given. These include a test of the overall intersec tion hypothesis with general weights, and weighted sequentially rejective procedures for testing the individual hypotheses. The false discovery rate controlling approach and procedure of Benjamini & Hochberg (1995) are extended to allow for different weights.
Children’s Interpretation of Ambiguous Behavior: Evidence for a ‘Boys are Bad’ Bias
Authors: Heyman Gail D.
Published: July 2002

Possible gender‐related evaluative biases were investigated among a group of 64 second and third graders (ages 6 y 11 m to 9 y 7 m). Participants were shown photographs of 8 unfamiliar children, and were told that each had performed a particular behavior. Each of the behaviors was consistent with multiple interpretations, including a positive interpretation and a negative interpretation. When the unfamiliar peers were male, participants were more likely to remember behaviors in unfavorable ways and to select more negative attributions for the behavior. This pattern of results held even among male participants, who reported greater expectations of liking the male peers.
Extracting information from mega‐panels and high‐frequency data
Authors: Granger C. W. J.
Published: July 2002

With the advent of very large data sets in economics, econometricians, with the help of statisticians, have to re‐evaluate current techniques and develop new procedures and their interpretation. Most tests of significance become irrelevant, for example, and conditional distributions become important, but difficult to report. Time series with high frequency data also present new and interesting questions.
Modeling large data sets in marketing
Authors: Balasubramanian S. , Gupta S. , Kamakura W. , Wedel M.
Published: July 2002

In the last two decades, marketing databases have grown significantly in terms of size and richness of available information. The analysis of these databases raises several information‐related and statistical issues. We aim at providing an overview of a selection of issues related to the analysis of large data sets. We focus on the two important areas: single source databases and customer transaction databases. We discuss models that have been used to describe customer behavior in these fields. Among the issues discussed are the development of parsimonious models, estimation methods, aggregation of data, data‐fusion and the optimization of customer‐level profit functions. We conclude that problems related to the analysis of large databases are far from resolved, and will stimulate new research avenues in the near future.
On Transition to Turbulence and Synthesis of Alternative Approaches
Authors: Lin C. C.
Published: July 2002

In the study of complex systems, controversial debates often arise among advocates of different schools of thought. In this article, we examine how such controversies should be addressed, with the problem of transition to turbulence as a primary example.

It is shown that, in many cases, these controversies may be resolved by first noting that the alternative theories proposed may not be mutually exclusive. Indeed, they may even be mutually complementary, if they were originally developed to address similar issues in different physical contexts. In any case, for the validity of the alternative theories proposed, each should be separately and fully supported from both the theoretical and empirical points of view. Each applies to a specific physical context, and each stands on its own merits and limitations. Synthesis into a broader theory may then be achieved, if commonality is identified among the different alternative theories proposed.

To demonstrate this conciliatory approach, we begin with an examination of the move toward resolution of the well‐known controversy over the problem of transition to turbulence from the steady laminar flow in the boundary layer over a flat plate. Several other long‐standing controversies have been successfully addressed on the basis of this approach. In addition to the problem of transition to turbulence, we considered, in some detail, two additional examples: (1) the global structures of spiral galaxies; and (2) the theory of jet noise. In all three cases, it is shown that the model approach is meritorious despite the limitations.

Synthesis, with a conciliatory approach to apparent conflicts, will be recommended in general as a new part of an extended paradigm in applied mathematics. It is an approach appropriate to situations where an ideal theory, with universal applicability, is elusive. Parallel development of several alternative theories is natural, and a final synthesis is needed. In contrast, it should be noted that the same perspective is generally not expected useful if the controversies concern the unique solution of well‐defined mathematical issues. The potential success of the application of this conciliatory perception and approach to other areas of science are discussed (see Section 5).
From Disorder to Order August 2000
Authors: Malkus Willem V. R.
Published: July 2002

Recently the “turbulent sublayer” was explored using a shear flow idealization akin to L. N. Howard's study of turbulent thermal convection [2]. There, the growing diffusive layers were studied to determine when they became unstable. Here, that work is extended to the first transitions of Couette and Poiseuille parallel flow. The merging boundary layers of the presumed flows pose a linear nonautonomous problem of following the time dependent first Lyapunov vector. As in Blasius flow, the first results emerge from perturbation theory, with corrections for streamwise evolution of the velocity profiles. The estimated critical Reynolds numbers for [back] transition from disorder to the laminar state are within 15% of the observations.
Resonant Triads Involving a Nondispersive Wave
Authors: Rosales Rodolfo R. , Tabak Esteban G. , Turner Cristina V.
Published: July 2002

A simple system is studied, involving a single nondispersive breaking wave and its interaction with two dispersive modes through a resonant triad. The dynamics of this system are shown to be quite rich, through a combined theoretical and numerical analysis. A sharply defined traveling wave with a corner seems to attract almost all initial data with enough energy, provided the nondispersive wave is unstable to the other two when standing alone. In other cases, the solution converges to quasiperiodic final states, unless extra symmetries force the solution to converge to simpler configurations.
Dynamic asymmetry of phosphocreatine concentration and O2 uptake between the on‐ and off‐transients of moderate‐ and high‐intensity exercise in humans
Authors: Rossiter H. B. , Ward S. A. , Kowalchuk J. M. , Howe F. A. , Griffiths J. R. , Whipp B. J.
Published: July 2002

The on‐ and off‐transient (i.e. phase II) responses of pulmonary oxygen uptake (V̇O2) to moderate‐intensity exercise (i.e. below the lactate threshold, θL) in humans has been shown to conform to both mono‐exponentiality and ‘on‐off’ symmetry, consistent with a system manifesting linear control dynamics. However above θL the V̇O2 kinetics have been shown to be more complex: during high‐intensity exercise neither mono‐exponentiality nor ‘on‐off’ symmetry have been shown to appropriately characterise the V̇O2 response. Muscle [phosphocreatine] ([PCr]) responses to exercise, however, have been proposed to be dynamically linear with respect to work rate, and to demonstrate ‘on‐off’ symmetry at all work intenisties. We were therefore interested in examining the kinetic characteristics of the V̇O2 and [PCr] responses to moderate‐ and high‐intensity knee‐extensor exercise in order to improve our understanding of the factors involved in the putative phosphate‐linked control of muscle oxygen consumption. We estimated the dynamics of intramuscular [PCr] simultaneously with those of V̇O2 in nine healthy males who performed repeated bouts of both moderate‐ and high‐intensity square‐wave, knee‐extension exercise for 6 min, inside a whole‐body magnetic resonance spectroscopy (MRS) system. A transmit‐receive surface coil placed under the right quadriceps muscle allowed estimation of intramuscular [PCr]; V̇O2 was measured breath‐by‐breath using a custom‐designed turbine and a mass spectrometer system. For moderate exercise, the kinetics were well described by a simple mono‐exponential function (following a short cardiodynamic phase for V̇O2,), with time constants (τ) averaging: τV̇O2,on 35 ± 14 s (±s.d.), τ[PCr]on 33 ± 12 s, τV̇O2,off 50 ± 13 s and τ[PCr]off 51 ± 13 s. The kinetics for both V̇O2 and [PCr] were more complex for high‐intensity exercise. The fundamental phase expressing average τ values of τV̇O2,on 39 ± 4 s, τ[PCr]on 38 ± 11 s, τV̇O2,off 51 ± 6 s and τ[PCr]off 47 ± 11 s. An associated slow component was expressed in the on‐transient only for both V̇O2 and [PCr], and averaged 15.3 ± 5.4 and 13.9 ± 9.1 % of the fundamental amplitudes for V̇O2 and [PCr], respectively. In conclusion, the τ values of the fundamental component of [PCr] and V̇O2 dynamics cohere to within 10 %, during both the on‐ and off‐transients to a constant‐load work rate of both moderate‐ and high‐intensity exercise. On average, ≈90 % of the magnitude of the V̇O2 slow component during high‐intensity exercise is reflected within the exercising muscle by its [PCr] response.
Spatial heterogeneity of transmembrane potential responses of single guinea‐pig cardiac cells during electric field stimulation
Authors: Sharma Vinod , Tung Leslie
Published: July 2002

Changes in transmembrane voltage (Vm) of cardiac cells during electric field stimulation have a complex spatial‐ and time‐dependent behaviour that differs significantly from electrical stimulation of space‐clamped membranes by current pulses. A multisite optical mapping system was used to obtain 17 or 25 μm resolution maps of Vm along the long axis of guinea‐pig ventricular cells (n= 57) stained with voltage‐sensitive dye (di‐8‐ANEPPS) and stimulated longitudinally with uniform electric field (2, 5 or 10 ms, 3–62 V cm−1) pulses (n= 201). The initial polarizations of Vm responses (Vmr) varied linearly along the cell length and reversed symmetrically upon field reversal. The remainder of the Vm responses had parallel time courses among the recording sites, revealing a common time‐varying signal component (Vms). Vms was depolarizing for pulses during rest and hyperpolarizing for pulses during the early plateau phase. Vms varied in amplitude and time course with increasing pulse amplitude. Four types of plateau response were observed, with transition points between the different responses occurring when the maximum polarization at the ends of the cell reached values estimated as 60, 110 and 220 mV. Among the cells that had a polarization change of > 200 mV at their ends (for fields > 45 V cm−1), some (n= 17/25) had non‐parallel time courses among Vm recordings of the various sites. This implied development of an intracellular field (Ei) that was found to increase exponentially with time (τ= 7.2 ± 3.2 ms). Theoretical considerations suggest that Vms represents the intracellular potential (φi) as well as the average polarization of the cell, and that Vmr is the manifestation of the extracellular potential gradient resulting from the field stimulus. For cells undergoing field stimulation, φi acts as the cellular physiological state variable and substitutes for Vm, which is the customary variable for space‐clamped membranes.
Effects of chloride transport on bistable behaviour of the membrane potential in mouse skeletal muscle
Authors: Foppen R. J. Geukes , van Mil H. G. J. , van Heukelom J. Siegenbeek
Published: July 2002

The lumbrical skeletal muscle fibres of mice exhibited electrically bistable behaviour due to the nonlinear properties of the inwardly rectifying potassium conductance. When the membrane potential (Vm) was measured continuously using intracellular microelectrodes, either a depolarization or a hyperpolarization was observed following reduction of the extracellular potassium concentration (K+o) from 5.7 mm to values in the range 0.76–3.8 mm, and Vm showed hysteresis when K+o was slowly decreased and then increased within this range. Hypertonicity caused membrane depolarization by enhancing chloride import through the Na+–K+–2Cl− cotransporter and altered the bistable behaviour of the muscle fibres. Addition of bumetanide, a potent inhibitor of the Na+‐K+‐2Cl− cotransporter, and of anthracene‐9‐carboxylic acid, a blocker of chloride channels, caused membrane hyperpolarization particularly under hypertonic conditions, and also altered the bistable behaviour of the cells. Hysteresis loops shifted with hypertonicity to higher K+o values and with bumetanide to lower values. The addition of 80 μM BaCl2 or temperature reduction from 35 to 27 °C induced a depolarization of cells that were originally hyperpolarized. In the K+o range of 5.7–22.8 mm, cells in isotonic media (289 mmol kg−1) responded nearly Nernstianly to K+o reduction, i.e. 50 mV per decade; in hypertonic media this dependence was reduced to 36 mV per decade (319 mmol kg−1) or to 31 mV per decade (340 mmol kg−1). Our data can explain apparent discrepancies in ΔVm found in the literature. We conclude that chloride import through the Na+–K+–2Cl− cotransporter and export through Cl− channels influenced the Vm and the bistable behaviour of mammalian skeletal muscle cells. The possible implication of this bistable behaviour in hypokalaemic periodic paralysis is discussed.
Modulation of synchrony between single motor units during precision grip tasks in humans
Authors: Kilner J. M. , Alonso‐Alonso M. , Fisher R. , Lemon R. N.
Published: July 2002

During precision grip, coherence between motor cortex and hand muscle EMG oscillatory activity in the 15‐30 Hz range covaries with the compliance of the manipulated object. The current study investigated whether short‐term synchrony and coherence between discharges of single motor units (SMUs) in the first dorsal interosseous (1DI) muscle were similarly modulated by object compliance during precision grip. Eight subjects used index finger and thumb to grip two levers that were under robotic control. Guided by visual feedback of the lever force levels, subjects held the levers against a steady force of 1.3 N for 8 s; they then linearly increased the force to 1.6 N over a 2 s period and held for a further 8 s before linearly decreasing the force back to the 1.3 N level over another 2 s period. Subjects performed the task at two different levels of compliance, each with identical grip force levels. Both surface EMG and SMU activity were recorded from the 1DI muscle. Short‐term synchrony between the discharges of pairs of SMUs was assessed in the time domain by cross‐correlation and in the frequency domain by coherence analysis. Coherence was seen in two frequency ranges: 6‐12 Hz and 15‐30 Hz. The compliance of the gripped object had a significant effect on both short‐term synchronisation and coherence in the 15‐30 Hz range between SMUs; both were greater for the more compliant condition. There was no change in the 6‐12 Hz coherence.