bluuebunny/crossref_metadata_2025 huggingface dataset:
The Newell Test for a theory of cognition
Authors: Anderson John R. , Lebiere Christian
Published: April 2004

Newell (1980; 1990) proposed that cognitive theories be developed in an effort to satisfy multiple criteria and to avoid theoretical myopia. He provided two overlapping lists of 13 criteria that the human cognitive architecture would have to satisfy in order to be functional. We have distilled these into 12 criteria: flexible behavior, real-time performance, adaptive behavior, vast knowledge base, dynamic behavior, knowledge integration, natural language, learning, development, evolution, and brain realization. There would be greater theoretical progress if we evaluated theories by a broad set of criteria such as these and attended to the weaknesses such evaluations revealed. To illustrate how theories can be evaluated we apply these criteria to both classical connectionism (McClelland & Rumelhart 1986; Rumelhart & McClelland 1986b) and the ACT-R theory (Anderson & Lebiere 1998). The strengths of classical connectionism on this test derive from its intense effort in addressing empirical phenomena in such domains as language and cognitive development. Its weaknesses derive from its failure to acknowledge a symbolic level to thought. In contrast, ACT-R includes both symbolic and subsymbolic components. The strengths of the ACT-R theory derive from its tight integration of the symbolic component with the subsymbolic component. Its weaknesses largely derive from its failure, as yet, to adequately engage in intensive analyses of issues related to certain criteria on Newell's list.
The problem of content in embodied memory
Authors: Kurthen Martin , Grunwald Thomas , Helmstaedter Christoph , Elger Christian E.
Published: April 2004

An action-oriented theory of embodied memory is favorable for many reasons, but it will not provide a quick yet clean solution to the grounding problem in the way Glenberg (1997t) envisages. Although structural mapping via analogical representations may be an adequate mechanism of cognitive representation, it will not suffice to explain representation as such.
A multilevel approach to modeling human cognition
Authors: Wang Hongbin , Johnson Todd R. , Zhang Jiajie
Published: April 2004

Although we agree with Newell and Anderson & Lebiere (A&L) that a unified theory of cognition is needed to advance cognitive science, we disagree on how to achieve it. A hybrid system can score high in the Newell Test but may not offer a veridical and coherent theory of cognition. A multilevel approach, involving theories at both psychological and brain levels, is suggested.
“Unintended consequences”: Can legalizing
physician-assisted suicide actually result in improved palliative care
practices?
Authors: BREITBART WILLIAM
Published: April 2004

In this issue of Palliative & Supportive Care, we are
pleased to present recent work from Dr. E.R. Goy et al. (“Oregon
hospice nurses and social workers' assessment of physician
progress in palliative care over the past 5 years”) regarding
their observations of the impact of the legalization of
physician-assisted suicide in the state of Oregon. In 1977, Oregon
enacted the Death with Dignity Act, which legalized physician-assisted
suicide for terminally ill patients. In the past 5 years, a relatively
small number of terminally ill patients in Oregon have requested
assisted suicide and, after evaluation, were provided with physician
assistance (Ganzini et al., 2002).
Enteric P2X receptors as potential targets for drug treatment of the irritable bowel syndrome
Authors: Galligan James J
Published: April 2004

The irritable bowel syndrome (IBS) is a gastrointestinal motility disorder affecting millions of patients. IBS symptoms include diarrhea, constipation and pain. The etiology of IBS is due partly to changes in the function of nerves supplying the gastrointestinal tract, immune system activation and to psychological factors. P2X receptors are multimeric ATP‐gated cation channels expressed by neuronal and non‐neuronal cells. Sensory nerve endings in the gastrointestinal tract express P2X receptors. ATP released from gastrointestinal cells activates P2X receptors on sensory nerve endings to stimulate motor reflexes and to transmit nociceptive signals. Antagonists acting at P2X receptors on sensory nerves could attenuate abdominal pain in IBS patients. Primary afferent neurons intrinsic to the gut, and enteric motor‐ and interneurons express P2X receptors. These neurons participate in motor reflexes. Agonists acting at enteric P2X receptors may enhance gastrointestinal propulsion and secretion, and these drugs could be useful for treating constipation‐predominant IBS. Antagonists acting at enteric P2X receptors would decrease propulsion and secretion and they might be useful for treating diarrhea‐predominant IBS. Current knowledge of P2X receptor distribution and function in the gut of laboratory animals provides a rational basis for further exploration of the therapeutic potential for drugs acting at P2X receptors in IBS patients. However, more information about P2X receptor distribution and function in the human gastrointestinal tract is needed. Data on the distribution and function of P2X receptors on gastrointestinal immune cells would also provide insights into the therapeutic potential of P2X receptor agents in IBS.

British Journal of Pharmacology (2004) 141, 1294–1302. doi:10.1038/sj.bjp.0705761
Polyandry in a marine turtle: Females make the best of a bad job
Authors: Lee Patricia L. M. , Hays Graeme C.
Published: April 2004

The female perspective on reproductive strategies remains one of the most active areas of debate in biology. Even though a single mating is often sufficient to satisfy the fertilization needs of most females and the act of further mating incurs costs, multiple paternity within broods or clutches is a common observation in nature. Direct or indirect advantage to females is the most popular explanation. However, the ubiquity of this explanation is being challenged by an increasing number of cases for which benefits are not evident. For the first time, we test possible fitness correlates of multiple paternity in a marine turtle, an organism that has long attracted attention in this area of research. Contrary to the wide-spread assumption that multiple mating by female marine turtles confers fitness benefits, none were apparent. In this study, the environment played a far stronger role in determining the success of clutches than whether paternity had been single or multiple. A more likely explanation for observations of multiply sired clutches in marine turtles is that these are successful outcomes of male coercion, where females have conceded to superfluous matings as a compromise. Thus, multiple matings by female marine turtles may be a form of damage control as females attempt to make the best of a bad job in response to male harassment.
New RNA motifs suggest an expanded scope for riboswitches in bacterial genetic control
Authors: Barrick Jeffrey E. , Corbino Keith A. , Winkler Wade C. , Nahvi Ali , Mandal Maumita , Collins Jennifer , Lee Mark , Roth Adam , Sudarsan Narasimhan , Jona Inbal , Wickiser J. Kenneth , Breaker Ronald R.
Published: April 2004

The expression of certain genes involved in fundamental metabolism is regulated by metabolite-binding “riboswitch” elements embedded within their corresponding mRNAs. We have identified at least six additional elements within the
Bacillus subtilis
genome that exhibit characteristics of riboswitch function (
glmS
,
gcvT
,
ydaO/yuaA
,
ykkC/yxkD
,
ykoK
, and
yybP/ykoY
). These motifs exhibit extensive sequence and secondary-structure conservation among many bacterial species and occur upstream of related genes. The element located upstream of the
glmS
gene in Gram-positive organisms functions as a metabolite-dependent ribozyme that responds to glucosamine-6-phosphate. Other motifs form complex folded structures when transcribed as RNA molecules and carry intrinsic terminator structures. These findings indicate that riboswitches serve as a major genetic regulatory mechanism for the control of metabolic genes in many microbial species.
Parietal cortex and representation of the mental Self
Authors: Lou Hans C. , Luber Bruce , Crupain Michael , Keenan Julian P. , Nowak Markus , Kjaer Troels W. , Sackeim Harold A. , Lisanby Sarah H.
Published: April 2004

For a coherent and meaningful life, conscious self-representation is mandatory. Such explicit “autonoetic consciousness” is thought to emerge by retrieval of memory of personally experienced events (“episodic memory”). During episodic retrieval, functional imaging studies consistently show differential activity in medial prefrontal and medial parietal cortices. With positron-emission tomography, we here show that these medial regions are functionally connected and interact with lateral regions that are activated according to the degree of self-reference. During retrieval of previous judgments of Oneself, Best Friend, and the Danish Queen, activation increased in the left lateral temporal cortex and decreased in the right inferior parietal region with decreasing self-reference. Functionally, the former region was preferentially connected to medial prefrontal cortex, the latter to medial parietal. The medial parietal region may, then, be conceived of as a nodal structure in self-representation, functionally connected to both the right parietal and the medial prefrontal cortices. To determine whether medial parietal cortex in this network is essential for episodic memory retrieval with self-representation, we used transcranial magnetic stimulation over the region to transiently disturb neuronal circuitry. There was a decrease in the efficiency of retrieval of previous judgment of mental Self compared with retrieval of judgment of Other with transcranial magnetic stimulation at a latency of 160 ms, confirming the hypothesis. This network is strikingly similar to the network of the resting conscious state, suggesting that self-monitoring is a core function in resting consciousness.
An aminoacyl-tRNA synthetase-like protein encoded by the
Escherichia coli yadB
gene glutamylates specifically tRNA
Asp
Authors: Dubois Daniel Y. , Blaise Mickaël , Becker Hubert D. , Campanacci Valérie , Keith Gérard , Giegé Richard , Cambillau Christian , Lapointe Jacques , Kern Daniel
Published: April 2004

The product of the
Escherichia coli yadB
gene is homologous to the N-terminal part of bacterial glutamyl-tRNA synthetases (GluRSs), including the Rossmann fold with the acceptor-binding domain and the stem-contact fold. This GluRS-like protein, which lacks the anticodon-binding domain, does not use tRNA
Glu
as substrate
in vitro
nor
in vivo
, but aminoacylates tRNA
Asp
with glutamate. The
yadB
gene is expressed in wild-type
E. coli
as an operon with the
dksA
gene, which encodes a protein involved in the general stress response by means of its action at the translational level. The fate of the glutamylated tRNA
Asp
is not known, but its incapacity to bind elongation factor Tu suggests that it is not involved in ribosomal protein synthesis. Genes homologous to
yadB
are present only in bacteria, mostly in Proteobacteria. Sequence alignments and phylogenetic analyses show that the YadB proteins form a distinct monophyletic group related to the bacterial and organellar GluRSs (α-type GlxRSs superfamily) with ubiquitous function as suggested by the similar functional properties of the YadB homologue from
Neisseria meningitidis
.
Lack of the Rhesus protein Rh1 impairs growth of the green alga
Chlamydomonas reinhardtii
at high CO
2
Authors: Soupene Eric , Inwood William , Kustu Sydney
Published: April 2004

Although Rhesus (Rh) proteins are best known as antigens on human red blood cells, they are not restricted to red cells or to mammals, and hence their primary biochemical functions can be studied in more tractable organisms. We previously established that the Rh1 protein of the green alga
Chlamydomonas reinhardtii
is highly expressed in cultures bubbled with air containing high CO
2
(3%), conditions under which
Chlamydomonas
grows rapidly. By RNA interference, we have now obtained
Chlamydomonas rh
mutants (epigenetic), which are among the first in nonhuman cells. These mutants have essentially no mRNA or protein for
RH1
and grow slowly at high CO
2
, apparently because they fail to equilibrate this gas rapidly. They grow as well as their parental strain in air and on acetate plus air. However, during growth on acetate,
rh1
mutants fail to express three proteins that are known to be down-regulated by high CO
2
: periplasmic and mitochondrial carbonic anhydrases and a chloroplast envelope protein. This effect is parsimoniously rationalized if the small amounts of Rh1 protein present in acetate-grown cells of the parental strain facilitate leakage of CO
2
generated internally. Together, these results support our hypothesis that the Rh1 protein is a bidirectional channel for the gas CO
2
. Our previous studies in a variety of organisms indicate that the only other members of the Rh superfamily, the ammonium/methylammonium transport proteins, are bidirectional channels for the gas NH
3
. Physiologically, both types of gas channels can apparently function in acquisition of nutrients and/or waste disposal.
Severe acute respiratory syndrome coronavirus spike protein expressed by attenuated vaccinia virus protectively immunizes mice
Authors: Bisht Himani , Roberts Anjeanette , Vogel Leatrice , Bukreyev Alexander , Collins Peter L. , Murphy Brian R. , Subbarao Kanta , Moss Bernard
Published: April 2004

The spike protein (S), a membrane component of severe acute respiratory syndrome coronavirus (SARS-CoV) is anticipated to be an important component of candidate vaccines. We constructed recombinant forms of the highly attenuated modified vaccinia virus Ankara (MVA) containing the gene encoding full-length SARS-CoV S with and without a C-terminal epitope tag called MVA/S-HA and MVA/S, respectively. Cells infected with MVA/Sor MVA/S-HA synthesized a 200-kDa protein, which was recognized by antibody raised against a synthetic peptide of SARS-CoV S or the epitope tag in Western blot analyses. Further studies indicated that S was N
-
glycosylated and migrated in SDS polyacrylamide gels with an apparent mass of ≈160 kDa after treatment with peptide N-glycosidase F. The acquisition of resistance to endoglycosidase H indicated trafficking of S to the medial Golgi compartment, and confocal microscopy showed that S was transported to the cell surface. Intranasal or intramuscular inoculations of BALB/c mice with MVA/S produced serum antibodies that recognized the SARS S in ELISA and neutralized SARS-CoV
in vitro
. Moreover, MVA/S administered by either route elicited protective immunity, as shown by reduced titers of SARS-CoV in the upper and lower respiratory tracts of mice after challenge. Passive transfer of serum from mice immunized with MVA/S to naïve mice also reduced the replication of SARS-CoV in the respiratory tract after challenge, demonstrating a role for antibody to S in protection. The attenuated nature of MVA and the ability of MVA/S to induce neutralizing antibody that protects mice support further development of this candidate vaccine.
A truncated aminoacyl–tRNA synthetase modifies RNA
Authors: Salazar Juan C. , Ambrogelly Alexandre , Crain Pamela F. , McCloskey James A. , Söll Dieter
Published: April 2004

Aminoacyl–tRNA synthetases are modular enzymes composed of a central active site domain to which additional functional domains were appended in the course of evolution. Analysis of bacterial genome sequences revealed the presence of many shorter aminoacyl–tRNA synthetase paralogs. Here we report the characterization of a well conserved glutamyl–tRNA synthetase (GluRS) paralog (YadB in
Escherichia coli
) that is present in the genomes of >40 species of proteobacteria, cyanobacteria, and actinobacteria. The
E. coli yadB
gene encodes a truncated GluRS that lacks the C-terminal third of the protein and, consequently, the anticodon binding domain. Generation of a
yadB
disruption showed the gene to be dispensable for
E. coli
growth in rich and minimal media. Unlike GluRS, the YadB protein was able to activate glutamate in presence of ATP in a tRNA-independent fashion and to transfer glutamate onto tRNA
Asp
. Neither tRNA
Glu
nor tRNA
Gln
were substrates. In contrast to canonical aminoacyl–tRNA, glutamate was not esterified to the 3′-terminal adenosine of tRNA
Asp
. Instead, it was attached to the 2-amino-5-(4,5-dihydroxy-2-cyclopenten-1-yl) moiety of queuosine, the modified nucleoside occupying the first anticodon position of tRNA
Asp
. Glutamyl–queuosine, like canonical Glu–tRNA, was hydrolyzed by mild alkaline treatment. Analysis of tRNA isolated under acidic conditions showed that this novel modification is present in normal
E. coli
tRNA; presumably it previously escaped detection as the standard conditions of tRNA isolation include an alkaline deacylation step that also causes hydrolysis of glutamyl–queuosine. Thus, this aminoacyl–tRNA synthetase fragment contributes to standard nucleotide modification of tRNA.
TheDrosophilatctex-1 Light Chain Is Dispensable for Essential Cytoplasmic Dynein Functions but Is Required during Spermatid Differentiation
Authors: Li Min-gang , Serr Madeline , Newman Eric A. , Hays Thomas S.
Published: April 2004

Variations in subunit composition and modification have been proposed to regulate the multiple functions of cytoplasmic dynein. Here, we examine the role of the Drosophila ortholog of tctex-1, the 14-kDa dynein light chain. We show that the 14-kDa light chain is a bona fide component of Drosophila cytoplasmic dynein and use P element excision to generate flies that completely lack this dynein subunit. Remarkably, the null mutant is viable and the only observed defect is complete male sterility. During spermatid differentiation, the 14-kDa light chain is required for the localization of a nuclear “cap” of cytoplasmic dynein and for proper attachment between the sperm nucleus and flagellar basal body. Our results provide evidence that the function of the 14-kDa light chain in Drosophila is distinct from other dynein subunits and is not required for any essential functions in early development or in the adult organism.
An online database for the detection of novel archaeal sequences in human ESTs
Authors: Saunders Neil F. W. , Curmi Paul M. G. , Cavicchioli Ricardo
Published: April 2004

Summary: We have developed a rapid, automated screening system and online database to detect foreign sequences of archaeal origin in human expressed sequence tags. The aim of the screening is to detect transcripts that may be derived from novel, putative archaeal pathogens or symbionts.

Availability:  http://psychro.bioinformatics.unsw.edu.au/pathogen/index.php

Supplementary information:  http://psychro.bioinformatics.unsw.edu.au/pathogen/about.php
Metabolite fingerprinting: detecting biological features by independent component analysis
Authors: Scholz M. , Gatzek S. , Sterling A. , Fiehn O. , Selbig J.
Published: April 2004

Motivation: Metabolite fingerprinting is a technology for providing information from spectra of total compositions of metabolites. Here, spectra acquisitions by microchip-based nanoflow-direct-infusion QTOF mass spectrometry, a simple and high throughput technique, is tested for its informative power. As a simple test case we are using Arabidopsis thaliana crosses. The question is how metabolite fingerprinting reflects the biological background. In many applications the classical principal component analysis (PCA) is used for detecting relevant information. Here a modern alternative is introduced—the independent component analysis (ICA). Due to its independence condition, ICA is more suitable for our questions than PCA. However, ICA has not been developed for a small number of high-dimensional samples, therefore a strategy is needed to overcome this limitation.

Results: To apply ICA successfully it is essential first to reduce the high dimension of the dataset, by using PCA. The number of principal components determines the quality of ICA significantly, therefore we propose a criterion for estimating the optimal dimension automatically. The kurtosis measure is used to order the extracted components to our interest. Applied to our A. thaliana data, ICA detects three relevant factors, two biological and one technical, and clearly outperforms the PCA.
Stabilization of discordant helices in amyloid fibril‐forming proteins
Authors: Päiviö Anna , Nordling Erik , Kallberg Yvonne , Thyberg Johan , Johansson Jan
Published: April 2004

Several proteins and peptides that can convert from α‐helical to β‐sheet conformation and form amyloid fibrils, including the amyloid β‐peptide (Aβ) and the prion protein, contain a discordant α‐helix that is composed of residues that strongly favor β‐strand formation. In their native states, 37 of 38 discordant helices are now found to interact with other protein segments or with lipid membranes, but Aβ apparently lacks such interactions. The helical propensity of the Aβ discordant region (K16LVFFAED23) is increased by introducing V18A/F19A/F20A replacements, and this is associated with reduced fibril formation. Addition of the tripeptide KAD or phospho‐L‐serine likewise increases the α‐helical content of Aβ(12–28) and reduces aggregation and fibril formation of Aβ(1–40), Aβ(12–28), Aβ(12–24), and Aβ(14–23). In contrast, tripeptides with all‐neutral, all‐acidic or all‐basic side chains, as well as phosphoethanolamine, phosphocholine, and phosphoglycerol have no significant effects on Aβ secondary structure or fibril formation. These data suggest that in free Aβ, the discordant α‐helix lacks stabilizing interactions (likely as a consequence of proteolytic removal from a membrane‐associated precursor protein) and that stabilization of this helix can reduce fibril formation.
Proteins can convert to β‐sheet in single crystals
Authors: Zheng Run , Zheng Xiaojing , Dong Jian , Carey Paul R.
Published: April 2004

Raman microscopy was used to follow conformational changes in single protein crystals. Crystals of native insulin and of the 5S and 12S subunits of the enzyme transcarboxylase showed a mixture of Raman marker bands signifying α‐helix, β‐sheet and nonordered secondary structure. However, by reducing the S–S bonds in the insulin crystal, or by lowering the pH for the 5S crystal, or by soaking substrates into the 12S crystal, the secondary structure in each crystal became predominantly β‐sheet. The β‐form crystals could be dissolved only with difficulty and yielded high–molecular weight protein aggregates, indicating that the β‐sheet formation involves intermolecular contacts. Although their morphology appeared unchanged, the crystals no longer diffracted X‐rays. Using crystals that had not been exposed to laser light, the dye thioflavin T formed highly fluorescent complexes with the “β‐transformed” crystals but not with the native crystals.
Prenatal diagnosis of de novo X;autosome translocations
Authors: Abrams L , Cotter PD
Published: April 2004

The identification of a de novo apparently balanced structural chromosome rearrangement at prenatal diagnosis can be problematic and raises unique genetic counseling issues. Two breakpoint rearrangements such as reciprocal translocations or inversions have a 6.7% empiric risk of phenotypic abnormality. Abnormal phenotypes are thought to result from gene disruption, position effect, or deletion at one of the breakpoints. Prenatal diagnosis of de novo X;autosome translocations is rare, and presents additional unique risks due to the effects of X‐inactivation and the possibility of disruption of the single active copy of an X‐linked gene. We report the identification of a de novo apparently balanced t(X;6)(q26;q23) ascertained after amniocentesis for advanced maternal age. The parents were counseled regarding the risk of a de novo apparently balanced translocation, including the potential risk of an X‐linked Mendelian disorder resulting from disruption of a gene at the Xq26 breakpoint. While the normal X chromosome was late replicating in all metaphases, no conclusions from this data could be drawn as the X‐inactivation ratio in amniocytes might not be representative of other tissues. The possibility of future premature ovarian failure was also noted due to the position of the breakpoint at Xq26, although no specific risk could be ascribed. The parents elected to continue the pregnancy, and at 17 months of age, the proband was phenotypically and developmentally normal. Long‐term follow‐up will be required to assess development delay and any fertility issues. Based on review of the few cases reported to date and excluding any risk for later reproductive abnormalities, we estimated the risk of phenotypic abnormality or developmental delay in a prenatally ascertained de novo X;autosome carrier to be as high as 50%. This case illustrates the complexities in counseling for prenatally ascertained de novo X;autosome translocations and the need for additional cases to be reported.
Heart Strings and Purse Strings
Authors: Lerner Jennifer S. , Small Deborah A. , Loewenstein George
Published: April 2004

We examined the impact of specific emotions on the endowment effect, the tendency for selling prices to exceed buying or “choice” prices for the same object. As predicted by appraisal-tendency theory, disgust induced by a prior, irrelevant situation carried over to normatively unrelated economic decisions, reducing selling and choice prices and eliminating the endowment effect. Sadness also carried over, reducing selling prices but increasing choice prices—producing a “reverse endowment effect” in which choice prices exceeded selling prices. The results demonstrate that incidental emotions can influence decisions even when real money is at stake, and that emotions of the same valence can have opposing effects on such decisions.
Amodal Completion in Visual Search
Authors: Rauschenberger Robert , Peterson Mary A. , Mosca Fauzia , Bruno Nicola
Published: April 2004

In a previous study, search for a notched-disk target abutting a square among complete-disk nontargets and squares was inefficient in 250-ms exposures, but relatively efficient in 100-ms exposures. This finding was interpreted as evidence that amodal completion proceeds through a mosaic and then a completion stage, with the latter preempting the former. We used the same target but changed its context: Nontargets were instead notched disks near squares. Task set was also different: Participants searched for a complete disk. Contrary to the prediction of the preemption model, search was efficient in the 100-ms condition and inefficient in the 250-ms condition. We propose that in both the present and the previous studies, the target was ambiguous, and task set and context affected how it was perceived. In both experiments, set effects were evident for 100-ms exposures; context effects were evident for 250-ms exposures.
Reversible scaling of dihedral angle barriers during molecular dynamics to improve structure prediction of cyclic peptides
Authors: Riemann R.N. , Zacharias M.
Published: April 2004

Abstract:  Peptide cyclization or chemical cross‐linking has frequently been used to restrict the conformational freedom of a peptide, for example, to enhance its capacity for selective binding to a target receptor molecule. Structure prediction of cyclic peptides is important to evaluate possible conformations prior to synthesis. Because of the conformational constraints imposed by cyclization low energy conformations of cyclic peptides can be separated by large energy barriers. In order to improve the conformational search properties of molecular dynamics (MD) simulations a potential scaling method has been designed. The approach consists of several consecutive MD simulations with a specific lowering of dihedral energy barriers and reduced nonbonded interactions between atoms separated by three atoms followed by gradually scaling the potential until the original barriers are reached. Application to four cyclic penta‐ and hexa‐peptide test cases and a protein loop of known structure indicates that the potential scaling method is more efficient and faster in locating low energy conformations than standard MD simulations. Combined with a generalized Born implicit solvation model the low energy cyclic peptide conformations and the loop structure are in good agreement with experiment. Applications in the presence of explicit water molecules during the simulations showed also improved convergence to structures close to experiment compared with regular MD.
Capital Income Taxes and Growth in a Stochastic Economy: A Numerical Analysis of the Role of Risk Aversion and Intertemporal Substitution
Authors: Chatterjee Santanu , Giuliano Paola , Turnovsky Stephen J.
Published: April 2004

This paper undertakes a numerical analysis of the effects of changes in the tax rates on domestic and foreign capital income in a stochastically growing open economy under recursive preferences, in which the rate of time preference, ɛ, and the coefficient of risk aversion, R, can be set independently. The responses of the equilibrium growth rate, its volatility, and welfare to changes in the tax changes considered are highly sensitive to the independent variations in both ɛ and R. Consequently, the errors committed by using the conventional constant elasticity utility function, even for small violations of the compatibility condition (R= 1/ɛ) can be significant, suggesting that this functional form should be employed with caution.
Hepatocellular carcinomas <2 cm in diameter complicating cirrhosis: ultrasound and clinical features in 153 consecutive patients
Authors: Rapaccini Gian Ludovico , Pompili Maurizio , Caturelli Eugenio , Covino Marcello , Lippi Maria Enrichetta , Beccaria Samuela , Cedrone Augusto , Riccardi Laura , Siena Domenico Angelo , Gasbarrini Giovanni
Published: April 2004

Abstract: Purpose: To determine the frequencies of various echogenicity patterns in 153 consecutive unifocal hepatocellular carcinomas (HCCs) <2 cm detected in cirrhotic livers and to identify their relationships with clinical, laboratory, and microscopic features.

Patients and methods: The tumors were classified as hypoechoic, hyperechoic, isoechoic, or nodule‐in‐nodule. Correlation was evaluated between hypoechoic and hyperechoic patterns and the following variables: age, gender, serum alphafetoprotein (AFP), tumor size, ultrasound features of liver parenchyma, cirrhosis etiology, and cyto/histological tumor grading.

Results: One hundred and seventeen tumors (76.4%) were hypoechoic, 26 (17.0%) were hyperechoic, 5 (3.3%) were isoechoic, and 5 (3.3%) had nodule‐in‐nodule patterns. The hyperechoic pattern was more common in patients under 69 years (25.0% vs. 11.3% in those under 69 years or older, P=0.033). Patients with a hyperechoic pattern displayed a trend towards lower AFP levels and higher prevalence of hepatitis C‐related cirrhosis. The prevalence of well‐differentiated tumors was identical (56.6% and 56.5%) in the hypoechoic and hyperechoic subgroups. AFP was higher than 400 ng/ml in only 11/153 cases (7.2%).

Conclusions: The hyperechoic pattern of HCC is by no means uncommon, particularly in patients under 70. Hyperechogenicity is not related to an increased frequency of well‐differentiated tumors. AFP shows limited value as a confirmatory test of small HCC.
Predictive Ability of Social Cognitive Theory in Exercise Research: An Integrated Literature Review
Authors: Keller Colleen , Fleury Julie , Gregor‐Holt Nansi , Thompson Terris
Published: April 2004

(1) The mechanisms that underlie successful initiation and adherence to physical activity regimens are not well understood. Few theoretical models have used consistent explanatory variables that are theory‐driven and many findings that use extant models are equivocal. Social Cognitive Theory (SCT) as presented by Bandura (1986 [4], 1997 [5]) appears to have strong promise as a guide to understanding physical activity behaviors and developing clinically relevant interventions to promote the initiation and maintenance of physical activity. This critical systematic review of research using SCT was completed to determine the predictive ability of model constructs in explaining physical activity behavior and in identifying key intervention components found to enhance physical activity initiation and maintenance. Following review for quality and adequacy, published research during the years 1990‐1998 contained 27 studies that examined the relationship between the construct of SCT, self‐efficacy, and physical activity. All of the descriptive studies found a statistically significant relationship between self‐efficacy and exercise behavior. Intervention studies demonstrated that participation in an exercise program promoted self‐efficacy, and that programs designed to increase outcome expectations and self‐efficacy significantly increased exercise behavior.

(2) Due to the centrality of self‐efficacy in many of the social psychological theories that help explain the attitude‐intention‐behavior triad, a strong need remains to design interventions to maximize its usefulness. Clear, generalizable, systematic and theoretically comprehensive, randomized, controlled studies are needed to understand the usefulness of the construct.
Exercise in Heart Failure: A Synthesis of Current Research
Authors: Adams Cynthia D. , Bennett Susan
Published: April 2004

(1) Exercise intolerance, as a hallmark symptom in patients with heart failure, has been the focus of numerous research initiatives in recent years. The purpose of this review is to synthesize the current literature in order to provide the clinician with an understanding of the state of knowledge regarding the role of exercise in treatment of heart failure. Many studies speak to the effect of exercise training in this population. While sample sizes have been small and restricted predominantly to male subjects with ischemic cardiomyopathies, strong support has been documented in favor of beneficial effects of exercise in heart failure. Future research should target more representative subject pools (i.e., females, non‐ischemic cardiomyopathies, cultural minorities, frail elderly, and NYHA class IV), evaluation of impact on quality of life outcomes, exploration of different types and intensity of exercise, and formulation of specific activity prescription tools which can guide practitioners in making activity and/or exercise recommendations to those patients who have no access, or limited access, to cardiac rehabilitation programs.
Breast Cancer Risk Perception and Surveillance: An Integrative Review
Authors: Martin Wanda , Lobchuk Michelle
Published: April 2004

Purpose

A family history of breast cancer has taken on new meaning with the advancement of genetic technology and the discovery of genes related to breast cancer risk. The purpose of this review is to summarize and synthesize current literature on breast cancer risk perception and mammography screening practices as related to women who have a first‐degree relative with breast cancer.

Conclusions

Research has shown that women tend to overestimate their breast cancer risk and that risk counseling fails to have a significant effect. Inconsistent findings exist in relation to the effect of family history on screening behaviors and conflicting evidence in the relationship between risk perception and mammography use.

Implications

(3) Inaccurate risk perceptions for high‐risk women may be because of the inconsistent messages women are hearing in the media or from health care providers in regard to the efficacy of mammography. Practitioners need to be careful not to assume that a strong family history of breast cancer leads to increased perceived risk, which in turn promotes increased mammography use.
Childbearing and Women's Survival: New Evidence from Rural Bangladesh
Authors: Menken Jane , Duffy Linda , Kuhn Randall
Published: April 2004

Effects of childbearing on women's mortality and the implications of family planning programs in reducing these effects are examined in a 20‐year prospective study of more than 2,000 women in Matlab, Bangladesh. Maternal mortality is defined as a death occurring in the six weeks after childbirth. But childbearing may affect women's survival beyond this brief period. Additional hypotheses considered relate to 1) cumulative exposure to childbearing, whether measured by parity or pace of childbearing, 2) age at first birth, and 3) effects beyond the reproductive ages. The results offer no support to cumulative exposure hypotheses, showing no link between parity or pace of childbearing and mortality risk. Instead, we identify an extended period of heightened mortality risk associated with each birth—the year of the birth and the two subsequent years. Family planning programs, by reducing the number of children and therefore a woman's exposure to extended maternal mortality risk, potentially increase survival. Research is needed to identify and address the specific causes of extended maternal mortality risk so that appropriate ameliorative programs may be developed.
Methodological Issues and Considerations in Studying Family Businesses
Authors: Handler Wendy C.
Published: April 2004

This paper examines five methodological issues critical to the development of family firms research, and discusses the potential contribution of each for both the theory and practice of family firms.
Loss and Continuity in the Family Firm
Authors: Brown Fredda Herz
Published: April 2004

There is little in the family business literature that focuses on the greatest impediment to the succession process: actual, anticipated, or denied losses. In order to successfully handle the issues related to continuity, the consultant must understand and be able to help the family deal with the issues related to loss—particularly the ultimate loss, death. This article examines factors that determine how losses affect family business systems and offers suggestions for consultants about assessment and intervention in these situations.
Wellness in the Family Business
Authors: Stier Suzanne
Published: April 2004

This article addresses the unique opportunity that family business owners have to create worksite environments that promote wellness in employees while increasing productivity. By giving physical and psychological well-being the same importance as economic well-being, the company benefits through healthier employees, reduction of absenteeism, lower insurance costs, and increased productivity and worker satisfaction.
International Relationships in the Family Firm: The Effect on Leadership Succession
Authors: Seymour Kevin C.
Published: April 2004

This article reports the results of a study designed to expand understanding regarding the effects that the quality of the work relationship between the owner-manager and the successor has on the continuity of leadership in the family firm. Training of the successor and succession planning were used as measures of leadership continuity. A positive, significant association between the reported quality of the intergenerational work relationship and successor training was found. However, no positive, significant association between the quality of the work relationship and formal succession planning was established.
Ethnicity, Families, and Family Business: Implications for Practitioners
Authors: McGoldrick Monica , Troast John G.
Published: April 2004

Ethnicity is an important variable for practitioners in understanding family business systems, since ethnicity influences patterns of communication, values, relationships, and preferences in business practices.
Family Support in Home-Based Family Businesses
Authors: Beach Betty
Published: April 2004

The home-based family business draws in family members on both formal and informal levels. This article focuses on the role that families play, particularly when home-based work is chosen as a means to reconcile work and family demands. The article outlines the mechanics by which families become involved, noting the importance of spouses and children in providing both ideological and practical support for the business.
Family-Owned Home Businesses: Their Employees and Unpaid Helpers
Authors: Heck Ramona K. Z. , Walker Rosemary
Published: April 2004

Family-owned home-based businesses traditionally utilize a workforce of paid workers, contracting workers, and unpaid helpers. Each type of worker may be categorized as family, related, or unrelated. The research reported here shows that not all worker types increase business outputs. Family workers, family helpers, and unrelated workers contribute in positive ways to business outputs. In contrast, unpaid related helpers decrease net income, and contracting related workers increase the work hours of the business owner.
Home-Based Employment: Historical and Current Considerations
Authors: Owen Alma J. , Carsky Mary L. , Dolan Elizabeth M.
Published: April 2004

The purposes of this article are threefold. First, there is a brief review of current and historical research on home-based business with special emphasis on female home-based employment and the impact of such employment on family life. Second, a conceptual model for family work activities is advanced. Finally, concepts related to home-based employment that could be used to frame and describe the empirical study are specified.
Strategic Management of the Family Business: Past Research and Future Challenges
Authors: Sharma Pramodita , Chrisman James J. , Chua Jess H.
Published: April 2004

This article reviews the literature on family business from a strategic management perspective. In general, this literature is dominated by descriptive articles that typically focus on family relationships. However, the literature does not usually address how these relationships affect the performance of a family business. Taking a strategic management perspective, we outline a new set of objectives for family-business research. We also identify some of the key issues and gaps that should be explored in future studies if research is to contribute to improving the management practices and performance of family firms.
Choosing the Successor in New Zealand Family Farms
Authors: Keating Norah C. , Little Heather M.
Published: April 2004

Farmers in family businesses are often interested in generational succession. Yet farming parents are often unclear about the process of choosing a successor. We undertook a grounded-method study of the succession process among New Zealand farm families. The process included five stages: watching for interest, reducing the pool of eligibles, assessing commitment, compensating the others, and placing the successor. We make suggestions for future research that will test the model of succession, and for use of these findings by farm families who are contemplating family succession.
The [Re]-Emergence of Family Businesses in the Transforming Soviet Bloc: Family Contributions to Entrepreneurship Development in Romania
Authors: Pistrui David , Welsch Harold P. , Roberts Joseph S.
Published: April 2004

Through an intensive investigation of Romania, this study investigates various aspects of family businesses in the transforming Soviet Bloc. The study explores the relationships between entrepreneurship, family, and enterprise development. The objective of the paper is to probe societal elements impacting entrepreneurship, and to identify the level of family participation in the transforming economy of Romania. We find that family plays an important role in at least two ways: direct support of the business, and through the development of social, community, and economic networks.
The [Re]-Generation of Family-Business Entrepreneurship in the Balkans
Authors: Poutziouris Panikhos , O'Sullivan Katherine , Nicolescu Lumenita
Published: April 2004

This paper explores the development of the family-business sector during the post-socialist era in the Balkans. It establishes the profile of family-business entrepreneurship in the emerging markets of southeastern Europe. By focusing on the Bulgarian and Romanian experience, we present and briefly contrast the transitional variant of family-business entrepreneurship with the contours of the Greek family business system. Next, we map out the growth patterns of Balkan family ventures, including businesses in the agro-industrial, manufacturing and other commercial sectors. We conclude with some tentative policy recommendations aimed at enhancing the further development of family-business entrepreneurship in the Balkans.
Team Building and Conflict Management: Strategies for Family Businesses
Authors: Filbeck Greg , Smith Linda L.
Published: April 2004

In this study, we investigate the use of the Myers-Briggs Type Indicator (MBTI) as an instrument to improve relationships among family team members in family businesses. We conducted a workshop on personality differences based on the MBTI for the family management teams of four family businesses. Both before and after the workshops, members of each team completed a survey assessing their perceptions of interpersonal dynamics within the family business. Improved responses on the post-workshop survey show that educating family business members in personality differences can improve perceptions relating to the interpersonal dynamics within the family management team.
Important Attributes of Successors in Family Businesses: An Exploratory Study
Authors: Chrisman James J. , Chua Jess H. , Sharma Pramodita
Published: April 2004

Respondents from 485 family firms in Canada rated integrity and commitment to the business as the most important attributes of a successor. Results indicated that the older the family business and the longer the respondent's tenure in that business, the more important these attributes became. Birth order and gender were rated the least important, despite the attention the literature has given to those attributes.
Development of a Measure of the Characteristics of Family Business
Authors: Smyrnios Kosmas , Tanewski George , Romano Claudio
Published: April 2004

In Australia and, for that matter, globally, family business represents the most significant form of company ownership and is the largest employer group (Department of Industry, Science & Technology, 1995; Lank, 1995). Despite the significance of family business, few investigations have evaluated issues relating to the reliability and validity of measures used to collect data. This study is part of a larger evaluation that aims to develop a reliable and valid measure of family business. Findings from this research will help establish a reliable and valid measure of family businesses that may be used in other studies in this area.
The Family Factor: The Impact of Family Relationship Dynamics on Business-Owning Families during Transitions
Authors: Dunn Barbara
Published: April 2004

This paper presents preliminary findings from three longitudinal case studies forming part of ongoing doctoral research into the activities and dynamics of business-owning families as they address the tasks and issues required during their succession processes. Specifically, the paper qualitatively explores the nature, characteristics, and effects of family relationship dynamics in three family business systems undertaking the transfer of controlling ownership to the next generation (from father to son). A model is presented to describe the sources of anxiety “imperatives” and their management during transition processes. Conclusions are drawn about the characteristics of emotional dynamics in business-owning families and how these can, over time, hinder or help families manage these tasks.
Founders versus Descendants: The Profitability, Efficiency, Growth Characteristics and Financing in Large, Public, Founding-Family-Controlled Firms
Authors: McConaughy Daniel L. , Phillips G. Michael
Published: April 2004

This study examines the differences between founder-controlled firms and firms controlled by descendants or relatives of the founder. In general, we observe that founder-controlled firms grow faster and invest more in capital assets and research and development. However, descendant-controlled firms are more profitable. The results are consistent with a life-cycle view of the family firm in which the early years are characterized by rapid growth. The experience of the early years provides a basis for later, when the firm is more professionally run and can exploit its established position in the market.