bluuebunny/crossref_metadata_2025 huggingface dataset:
Predictors of reproductive cost in female Soay sheep
Authors: TAVECCHIA G. , COULSON T. , MORGAN B. J. T. , PEMBERTON J. M. , PILKINGTON J. C. , GULLAND F. M. D. , CLUTTON‐BROCK T. H.
Published: March 2005

We investigate factors influencing the trade‐off between survival and reproduction in female Soay sheep (Ovis aries). Multistate capture–recapture models are used to incorporate the state‐specific recapture probability and to investigate the influence of age and ecological conditions on the cost of reproduction, defined as the difference between survival of breeder and non‐breeder ewes on a logistic scale.

The cost is identified as a quadratic function of age, being greatest for females breeding at 1 year of age and when more than 7 years old. Costs, however, were only present during severe environmental conditions (wet and stormy winters occurring when population density was high).

Winter severity and population size explain most of the variation in the probability of breeding for the first time at 1 year of life, but did not affect the subsequent breeding probability.

The presence of a cost of reproduction was confirmed by an experiment where a subset of females was prevented from breeding in their first year of life.

Our results suggest that breeding decisions are quality or condition dependent. We show that the interaction between age and time has a significant effect on variation around the phenotypic trade‐off function: selection against weaker individuals born into cohorts that experience severe environmental conditions early in life can progressively eliminate low‐quality phenotypes from these cohorts, generating population‐level effects.
Large‐scale population dynamics, abundance–occupancy relationships and the scaling from local to regional population size
Authors: FRECKLETON R. P. , GILL J. A. , NOBLE D. , WATKINSON A. R.
Published: March 2005

We explore the relationship between patch occupancy and local abundance in a general model for regional population dynamics. We vary colonization ability and key demographic and habitat characteristics in order to explore the effects on abundance–occupancy relationships.

In populations in which colonization rates are very high, new habitat is rapidly colonized and there is a simple asymptotic relationship between occupancy and abundance, assuming that habitat quality and abundance are linked.

If colonization rates are moderate to low, as in metapopulations, there is similarly a positive relationship between occupancy and abundance, but there is a minimum abundance below which the metapopulation becomes extinct.

These responses are modulated by the occurrence of Allee effects, demographic stochasticity or depensatory effects: when such effects are significant, the metapopulation rescue effect becomes important, and regional occupancy becomes more sensitive to changes in local density.

Finally, in populations in which colonization rates are very low, there is no relationship between occupancy and abundance.

Our results emphasize two aspects of large‐scale ecology as being key in generating positive abundance‐occupancy relationships: (i) a relationship between average habitat quality and the proportion of habitat that is habitable; and (ii) the nature of colonization. It is important to note that colonization is a function of dispersal, fecundity, and local processes such as Allee effects, as well as the availability and isolation of habitat patches.

When an abundance–occupancy relationship exists there is typically a non‐linear scaling from local to total population sizes at low population densities, and we discuss how this may be detected in real data, as well as its implications.
Influence of marginal bone resorption on stress around an implant – a three‐dimensional finite element analysis
Authors: KITAMURA E. , STEGAROIU R. , NOMURA S. , MIYAKAWA O.
Published: March 2005

summary  Average marginal bone resorption of about 1 mm after the first year of functional loading, which is followed by an annual loss of approximately 0·1 mm, has been reported in stable implants. However, finite element analyses on bone stress around implants have been limited to analysing the bone stress in the absence of any bone resorption. Thus, a three‐dimensional finite element analysis was performed to compare the bone stresses in a non‐resorption model with those in four models with bone resorption of two depths (1·3 and 2·6 mm) and types (horizontal resorption and angular defects). Axial and bucco‐lingual forces were separately applied to the center of the superstructure and the maximum equivalent stress was calculated. The main tendencies of bone stress (highest stress concentration around implant neck, higher stresses under bucco‐lingual than axial load, as well as in the cortical than cancellous bone) were the same in the non‐resorption and resorption models. Bone stress distributions were similar in the non‐resorption and horizontal resorption models, but differed from those in the angular defect models. Moreover, the changes of the bone stress values with resorption depth differed for the two resorption types. Thus, in FEA, accurate simulation of the marginal bone shape in the implant neck region is advisable.
Effects of cantilever design and material on stress distribution in fixed partial dentures – a finite element analysis
Authors: ERASLAN O. , SEVİMAY M. , USUMEZ A. , ESKITASCIOGLU G.
Published: March 2005

summary  The purpose of this study was to examine the stress distribution in distal cantilevered fixed partial dentures (FPDs) that are designed with different cantilever morphology and made from different restorative materials. The finite element (FE) method was used to create models of two restoration types; metal‐ceramic and an all‐ceramic FPDs. Both models were designed with distal cantilevers involving the first and second premolars as abutments and cantilever extension involving at the premolar or molar. The width of connector between the cantilever and the primary abutment restoration was 2·25 mm. The load applied during the FE analysis was positioned at the cusp tips of all teeth. The FE analysis of the models revealed that Von Mises stress values with maximum stress concentrations were observed on connectors of distal cantilevers. Stress concentration sites were also observed at the distal cervical area of the second premolar tooth. Models with premolar cantilever extensions restored with all‐ceramic induced lower Von Mises stress values than metal‐ceramic restorations, however models with molar cantilever extensions restored with all‐ceramic restorations induced higher Von Misses stress values than metal‐ceramic restorations. If the distal cantilever length and restorative material is appropriately chosen, the failure frequency may be reduced. All ceramic can be used as restorative material, when the cantilevers length is not more than the mesiodistal dimension of a premolar tooth and metal‐ceramic restorations can be used in longer situations.
The pyruvate requirement of some members of the Mycobacterium tuberculosis complex is due to an inactive pyruvate kinase: implications for in vivo growth
Authors: Keating Lisa A. , Wheeler Paul R. , Mansoor Huma , Inwald Jacqueline K. , Dale James , Hewinson R. Glyn , Gordon Stephen V.
Published: March 2005

Through examination of one of the fundamental in vitro characteristics of Mycobacterium bovis– its requirement for pyruvate in glycerol medium – we have revealed a lesion in central metabolism that has profound implications for in vivo growth and nutrition. Not only is M. bovis unable to use glycerol as a sole carbon source but the lack of a functioning pyruvate kinase (PK) means that carbohydrates cannot be used to generate energy. This disruption in sugar catabolism is caused by a single nucleotide polymorphism in pykA, the gene which encodes PK, that substitutes glutamic acid residue 220 with an aspartic acid residue. Substitution of this highly conserved amino acid residue renders PK inactive and thus blocks the ATP generating roles of glycolysis and the pentose phosphate pathway. This mutation was found to occur in other members of the M. tuberculosis complex, namely M. microti and M. africanum. With carbohydrates unable to act as carbon sources, the importance of lipids and gluconeogenesis for growth in vivo becomes apparent. Complementation of M. bovis with the pykA gene from M. tuberculosis H37Rv restored growth on glycerol. Additionally, the presence of a functioning PK caused the colony morphology of the complemented strain to change from the characteristic dysgonic growth of M. bovis to eugonic growth, an appearance normally associated with M. tuberculosis. We also suggest that the glycerol‐soaked potato slices used for the derivation of the M. bovis bacillus Calmette and Guérin (BCG) vaccine strain selected for an M. bovis PK+ mutant, a finding that explains the alteration in colony morphology noted during the derivation of BCG. In summary, the disruption of a key step in glycolysis divides the M. tuberculosis complex into two groups with distinct carbon source utilization.
The HOG MAP kinase pathway is required for the induction of methylglyoxal‐responsive genes and determines methylglyoxal resistance in Saccharomyces cerevisiae
Authors: Aguilera Jaime , Rodríguez‐Vargas Sonia , Prieto Jose A.
Published: March 2005

A sudden overaccumulation of methylglyoxal (MG) induces, in Saccharomyces cerevisiae, the expression of MG‐protective genes, including GPD1, GLO1 and GRE3. The response is partially dependent on the transcriptional factors Msn2p/Msn4p, but unrelated with the general stress response mechanism. Here, we show that the high‐osmolarity glycerol (HOG)‐pathway controls the genetic response to MG and determines the yeast growth capacity upon MG exposure. Strains lacking the MAPK Hog1p, the upstream component Ssk1p or the HOG‐dependent nuclear factor Msn1p, showed a reduction in the mRNA accumulation of MG‐responsive genes after MG addition. Moreover, hyperactivation of Hog1p by deletion of protein phosphatase PTP2 enhanced the response, while blocking the pathway by deletion of the MAPKK PBS2 had a negative effect. In addition, the activity of Hog1p affected the basal level of GPD1 mRNA under non‐inducing conditions. These effects had a great influence on MG resistance, as hog1Δ and other HOG‐pathway mutants with impaired MG‐specific expression displayed MG sensitivity, whereas those with enhanced expression exhibited MG resistance as compared with the wild‐type. However, MG does not trigger the overphosphorylation of Hog1p or its nuclear import in the parental strain. Moreover, dual phosphorylation of Hog1p appears to be dispensable in the triggering of the transcriptional response, although a phosphorylable form of Hog1p is fundamental for the transcriptional activity. Overall, our results suggest that the basal activity of the HOG‐pathway serves to amplify the expression of MG‐responsive genes under non‐inducing and inducing conditions, ensuring cell protection against this toxic glycolytic by‐product.
Cryo‐electron microscopy reveals native polymeric cell wall structure in Bacillus subtilis 168 and the existence of a periplasmic space
Authors: Matias Valério R. F. , Beveridge Terry J.
Published: March 2005

Ultrarapid freezing of bacteria (i.e. vitrification) results in optimal preservation of native structure. In this study, cryo‐transmission electron microscopy of frozen‐hydrated sections was used to gain insight into the organization of the Bacillus subtilis 168 cell envelope. A bipartite structure was seen above the plasma membrane consisting of a low‐density 22 nm region above which a higher‐density 33 nm region or outer wall zone (OWZ) resided. The interface between these two regions appeared to possess the most mass. In intact and in teichoic acid‐extracted wall fragments, only a single region was seen but the mass distribution varied from being dense on the inside to less dense on the outside (i.e. similar to the OWZ). In plasmolysed cells, the inner wall zone (IWZ)'s thickness expanded in size but the OWZ's thickness remained constant. As the IWZ expanded it became filled with plasma membrane vesicles indicating that the IWZ had little substance and was empty of the wall's polymeric network of peptidoglycan and teichoic acid. Together these results strongly suggest that the inner zone actually represents a periplasmic space confined between the plasma membrane and the wall matrix and that the OWZ is the peptidoglycan‐teichoic acid polymeric network of the wall.
Trypanosoma brucei MOB1 is required for accurate and efficient cytokinesis but not for exit from mitosis
Authors: Hammarton Tansy C. , Lillico Simon G. , Welburn Sue C. , Mottram Jeremy C.
Published: March 2005

Two MOB1 genes, MOB1‐A and MOB1‐B, were identified in Trypanosoma brucei. MOB1‐A of T. brucei was shown to form a complex with TbPK50, a functional homologue of the Schizosaccharomyces pombe protein kinase Orb6, and immune precipitated MOB1‐A exhibited histone H1 protein kinase activity. MOB1‐A and TbPK50 were also shown to bind p12cks1, a cyclin‐dependent kinase accessory protein. Immune fluorescence of epitope‐tagged MOB1‐A and MOB1‐B in bloodstream form trypanosomes showed they had a punctate distribution all through the cell cytoplasm and were excluded from the nucleus throughout the cell cycle. Using RNA interference (RNAi), MOB1 was shown to be essential in both bloodstream and procyclic life cycle stages. In the bloodstream form, RNAi of MOB1 resulted, after 8 h, in a significant increase in post‐mitotic cells, the majority of which had a visible cleavage furrow. This was followed by the appearance of cells with abnormal complements of nuclei and kinetoplasts, often with the number of nuclei exceeding the number of kinetoplasts. Thus, downregulation of MOB1 in the bloodstream form results in a delay in cytokinesis, and leads to a deregulation of the cell cycle, possibly through an inhibitory effect on kinetoplast replication. In contrast, downregulation of MOB1 in the procyclic form appears to impede the accuracy of cytokinesis, by allowing mispositioning of the cleavage furrow and inappropriate cytokinesis. Unlike its counterpart in budding yeast, T. brucei MOB1 does not appear to be required for mitotic exit.
Low incidence of infectious complications after nonmyeloablative compared with myeloablative allogeneic stem cell transplantation
Authors: Meijer E. , Dekker A.W. , Lokhorst H.M. , Petersen E.J. , Nieuwenhuis H.K. , Verdonck L.F.
Published: March 2005

Abstract: Allogeneic stem cell transplantation (SCT) using a myeloablative (MA) conditioning regimen is limited to relatively young patients because of increased transplant‐related mortality in elderly patients. Nonmyeloablative (NMA) conditioning regimens have been developed aiming to reduce transplant mortality. In this study, we set out to evaluate the post‐transplant occurrence of infectious complications in recipients of grafts from human leukocyte antigen (HLA)‐identical sibling donors treated with either NMA or MA conditioning regimens. Data of 78 consecutively treated patients were analyzed. An NMA conditioning regimen was used in 40 patients and an MA regimen in 38 patients. A significantly lower rate of episodes of febrile neutropenia (0% vs. 34%, P<0.01) and post‐transplant Epstein–Barr virus reactivations (0% vs. 18%, P<0.05) was found in SCT recipients treated with an NMA conditioning regimen compared with an MA conditioning regimen. Furthermore, fewer invasive fungal infections (2% vs. 12%, not significant) were diagnosed in the NMA group. The incidence of cytomegalovirus (CMV) reactivations and bacterial infections was low in both groups (CMV reactivations: 13% in both groups; bacterial infections: 10% in the NMA group vs. 8% in the MA group), while CMV disease developed in only 1 patient. Overall, compared to our MA regimen, we found a very low rate of infectious complications after NMA SCT.
Spontaneous and directed application of verbal learning strategies in bipolar disorder and obsessive‐compulsive disorder
Authors: Deckersbach Thilo , Savage Cary R , Dougherty Darin D , Bohne Antje , Loh Rebecca , Nierenberg Andrew , Sachs Gary , Rauch Scott L
Published: March 2005

Objectives: Individuals with bipolar disorder exhibit neuropsychological impairments when they are euthymic (neither depressed nor manic). One of the most consistently reported cognitive problems in euthymic individuals with bipolar disorder is impairment in verbal episodic memory. Recent findings suggest that episodic memory difficulties in these individuals are attributable to difficulties using organizational strategies during encoding. The purpose of the present study was (i) to investigate whether difficulties using organizational strategies in bipolar disorder are due to a failure in spontaneously initiating verbal organization strategies or are due to difficulties implementing such strategies, and (ii) to compare the characteristics of verbal organizational impairment in bipolar disorder with those observed in individuals with obsessive–compulsive disorder (OCD).

Methods: Study participants were 20 individuals with bipolar I disorder (BP‐I), 20 individuals with OCD, and 20 healthy control participants matched for age, gender, and education. Participants completed a verbal encoding paradigm that involved spontaneous and directed use of verbal organization strategies during encoding of word lists.

Results: Compared with control subjects, both BP‐I and OCD participants showed impaired verbal organization in the spontaneous encoding condition. In the directed encoding condition, OCD patients organized the word lists as well as control participants whereas BP‐I participants exhibited lower verbal organization than both control and OCD participants. OCD and BP‐I participants’ free recall performance did not differ from that of control participants in the spontaneous encoding condition. In the directed encoding condition, BP‐I participants recalled fewer words than OCD or control participants.

Conclusions: Episodic memory difficulties in OCD are associated with difficulties spontaneously initiating verbal organization strategies during encoding whereas the ability to implement verbal organization when instructed to do so is preserved. BP‐I participants, on the other hand, exhibit difficulties in both spontaneously initiating verbal organization strategies and in the ability to implement such strategies when instructed to do so.
Age at onset in bipolar affective disorders: a review
Authors: Leboyer Marion , Henry Chantal , Paillere‐Martinot Marie‐Laure , Bellivier Frank
Published: March 2005

Bipolar affective disorder (BPAD) is a multifactorial disorder with various clinical presentations. Etiologic heterogeneity may partly underlie the phenotypic heterogeneity. Efforts to dissect BPAD have been based on the course of the disorders (BP I versus BP II or rapid cycling), cormorbidity pattern (panic attacks, suicide attempts, addiction or hyperactivity), differences between the sexes, and clinical pattern (cycloid and puerperal psychosis). The present article provides a comprehensive review of the existing data, showing that age at onset (AAO) identifies homogeneous sub‐groups of patients with BPAD. Recent work has demonstrated the existence of three – early, intermediate and late – onset bipolar sub‐groups based on AAO, following Kendell's criteria for validity (The American Journal of Psychiatry 2003; 160: 999). We will also show how these distinctions may be of use in the search for genetic vulnerability factors and other pathogenic influences. Following Kendell's criteria, we show that AAO of bipolar disorders has been tested with most of the available strategies for establishing the validity of clinical syndromes. We also present data from genetic epidemiologic studies in bipolar disorder, showing that AAO sub‐groups may reduce the underlying genetic heterogeneity. No accurate AAO thresholds to define valid sub‐groups have been identified precisely. Until recently, studies defined early‐ and late‐onset as corresponding to early or mid‐adulthood, not taking into account juvenile‐onset bipolar disorder. A recently proposed theoretical model with three AAO sub‐groups (onset age 17, 27 and 46) is discussed.
An investigation of prepulse inhibition in pediatric bipolar disorder
Authors: Rich Brendan A , Vinton Deborah , Grillon Christian , Bhangoo Robinder K , Leibenluft Ellen
Published: March 2005

Objectives:  Deficits in prepulse inhibition (PPI), a measure of sensorimotor gating, have been noted in psychopathologies including schizophrenia and adult bipolar disorder (BPD). Sensorimotor gating deficits may contribute to the emotional and behavioral dysregulation characteristic of pediatric BPD. The current study investigated possible PPI deficits in children with BPD.

Methods:  Sixteen children with BPD (medicated, euthymic and non‐psychotic) were compared with 13 control subjects on the magnitude of startle habituation, startle‐alone response, and inhibition of startle following a 60 or 120‐ms prepulse.

Results:  Both groups displayed startle inhibition by a prepulse, with no significant between‐group differences on the magnitude of inhibition after the 60‐ or 120‐ms prepulse. In addition, there were no between‐group differences on habituation or baseline startle response. PPI level was not significantly correlated with mood symptoms and did not differ based on comorbid attention deficit hyperactivity disorder.

Conclusions:  A lack of PPI deficits in our pediatric bipolar sample contrasts with previous results in adult bipolar and schizophrenic samples. These negative results may reflect the fact that our sample was medicated and was neither acutely manic nor psychotic. Deficits in sensorimotor gating may not be implicated in the emotional and behavioral dysregulation in pediatric BPD.
The burden on informal caregivers of people with bipolar disorder
Authors: Ogilvie Alan D , Morant Nicola , Goodwin Guy M
Published: March 2005

Abstract:  Caregivers of people with bipolar disorder may experience a different quality of burden than is seen with other illnesses. A better understanding of their concerns is necessary to improve the training of professionals working with this population. Conceptualizing caregiver burden in a conventional medical framework may not focus enough on issues important to caregivers, or on cultural and social issues. Perceptions of caregivers about bipolar disorder have important effects on levels of burden experienced. It is important to distinguish between caregivers’ experience of this subjective burden and objective burden as externally appraised. Caregivers’ previous experiences of health services may influence their beliefs about the illness. Caregiver burden is associated with depression, which affects patient recovery by adding stress to the living environment. The objective burden on caregivers of patients with bipolar disorder is significantly higher than for those with unipolar depression. Caregivers of bipolar patients have high levels of expressed emotion, including critical, hostile, or over‐involved attitudes. Several measures have been developed to assess the care burden of patients with depressive disorders, but may be inappropriate for patients with bipolar disorder because of its cyclical nature and the stresses arising from manic and hypomanic episodes. Inter‐episode symptoms pose another potential of burden in patients with bipolar disorder. Subsyndromal depressive symptoms are common in this phase of the illness, resulting in severe and widespread impairment of function. Despite the importance of assessing caregiver burden in bipolar disorder, relevant literature is scarce. The specific effects of mania and inter‐episode symptoms have not been adequately addressed, and there is a lack of existing measures to assess burden adequately, causing uncertainty regarding how best to structure family interventions to optimally alleviate burden. The relatively few studies into caregiver burden in bipolar disorder may largely reflect experiences in the US Veterans Affairs health service, but the findings may be limited in their generalizability. Nevertheless, available data suggest that caregiver burden is high and largely neglected in bipolar disorder. Clinically effective, well‐targeted and practically viable interventions are needed. However, services cannot be enhanced on a rational basis without an improved understanding and capacity to measure and target caregiver burden the impact of any change in services be evaluated.
Effects of Aβ1−42 fibrils and of the tetrapeptide Pr‐IIGL on the phosphorylation state of the τ‐protein and on the α7 nicotinic acetylcholine receptor in vitro
Authors: Lain Enzo , Penke Botond , Delacourte André , Gündisch Daniela , Schröder Hannsjörg , Witter Brigitte
Published: March 2005

In order to investigate the possible links connecting β‐amyloid (Aβ) accumulation, τ‐hyperphosphorylation and nicotinic receptor expression, rat embryonic primary hippocampal cultures were incubated with amyloidogenic peptides. Exposure to 0.5 µm fibrillar Aβ1−42 for 3 days caused retraction of dendrites, shrinkage of cell bodies and a decrease in the expression of microtubule‐associated proteins 2b (MAP2b), without affecting the total number of neurons and their viability. No impact on the τ‐phosphorylation sites Ser‐202, Thr231/Ser235, Ser262 and Ser396/Ser404 was found. The total number of homomeric α7‐nicotinic receptors (α7‐nAChRs) and their affinity for [125I]α‐bungarotoxin remained unaltered. Upon incubation with the putatively protective tetrapeptide propionyl–isoleucine–isoleucine–glycine–leucine (Pr‐IIGL), an analogue of the region [31–34] of Aβ, cell bodies were swollen in the region of the apical dendrite. These morphological alterations, different from those elicited by Aβ1−42, did not involve MAP2 expression changes. In contrast to Aβ1−42, Pr‐IIGL caused a massive hyperphosphorylation of the τ‐protein at Ser‐202 and at Ser396/Ser404. The total number of homomeric α7‐nAChRs and their affinity for [125I]α‐bungarotoxin were unaffected. In conclusion, the present results show a toxic effect of Aβ1−42 on the cytoskeletal structure at concentrations normally present in the brains of Alzheimer's disease patients, but raise some doubts about the role of Aβ1−42 fibrils as a direct trigger of τ‐hyperphosphorylation. The tetrapeptide Pr‐IIGL cannot be considered protective with regard to cell morphology. Although it prevents the Aβ1−42‐induced retraction of dendrites, it exhibits other toxic properties. The homomeric α7‐nAChRs were not affected either by Aβ1−42 incubation or by Pr‐IIGL‐induced τ‐hyperphosphorylation.
REM sleep: a sensitive index of fear conditioning in rats
Authors: Jha Sushil K. , Brennan Francis X. , Pawlyk Aaron C. , Ross Richard J. , Morrison Adrian R.
Published: March 2005

To examine the influence of conditioned fear stimuli on sleep‐wake states, we recorded sleep in Sprague–Dawley rats after exposure to tones previously paired with footshock. After habituation to a recording chamber and the recording procedure, a baseline sleep recording was obtained the next day. One day later, experimental animals were exposed to shock training designed to induce conditioned fear (FC), consisting of five tone‐footshock pairings. The 5‐s tones (conditioned stimuli; CS) co‐terminated with 1‐s footshocks (unconditioned stimuli; US). The next day sleep was recorded for 4 h in the recording chamber after presentation of five CSs alone. Sleep efficiency (total sleep time/recording period) and REM sleep (REM) and non‐REM (NREM) measures were determined. While sleep efficiency was not significantly changed after CS presentation, the percentage of total sleep time spent in REM (REM percentage) was reduced in the FC animals. The reduction in REM percentage in the FC animals was due to a decrease in the number of REM bouts. In a separate experiment, we repeated the procedures, except the tones and shocks were presented in an explicitly unpaired (UP) fashion. The next day, presentation of the tones increased REM percentage in the UP group. Results are discussed in terms of the decreases in REM as a response to conditioned fear, and the relevance of these findings to the sleep changes seen in post‐traumatic stress disorder (PTSD).
Learning and transfer from a simple dynamic system
Authors: JENSEN EVA
Published: March 2005

The amount of learning gained from being assisted in completing the task of bringing a predator‐prey system into equilibrium by controlling the predator population was investigated. Learning was explored both by post‐task questioning and by testing for transfer to another predator‐prey task. Participants were 28 undergraduate psychology students, all female. They were randomly and evenly split into an experiment group that was subjected to a learning session with the first task before being tested in the second task, and a control group that only performed the second task. What was most needed in the first task was help in sticking to analytically derived conclusions by resisting “common sense” responses. There was a significant transfer effect on performance to the second task, stemming from learning shown by half the participants in the experiment group. The other half showed hardly any learning. Learning in about half the subjects has proven a stable finding.
Testing log‐linear models with inequality constraints: a comparison of asymptotic, bootstrap, and posterior predictive p‐values
Authors: Galindo‐Garre Francisca , Vermunt Jeroen K.
Published: March 2005

An important aspect of applied research is the assessment of the goodness‐of‐fit of an estimated statistical model. In the analysis of contingency tables, this usually involves determining the discrepancy between observed and estimated frequencies using the likelihood‐ratio statistic. In models with inequality constraints, however, the asymptotic distribution of this statistic depends on the unknown model parameters and, as a result, there no longer exists an unique p‐value. Bootstrap p‐values obtained by replacing the unknown parameters by their maximum likelihood estimates may also be inaccurate, especially if many of the imposed inequality constraints are violated in the available sample. We describe the various problems associated with the use of asymptotic and bootstrap p‐values and propose the use of Bayesian posterior predictive checks as a better alternative for assessing the fit of log‐linear models with inequality constraints.
AN INFRA‐SURFER'S PARADISE: RIDING THE CREST OF THE LAND ‐ VALUE WAVE
Authors: Riley Don
Published: March 2005

The author devoted his working life to adding wealth to the nation. Now, to expose the damage caused by taxes to the enterprise economy, he is an accredited Infra‐surfer. And as he triangulates between deals in St Petersburg, up‐state New York and the coast of Spain, he finds himself slipping into a dream‐like world of virtual reality…
THE ECONOMIC CASE FOR IMMIGRATION1
Authors: Coyle Diane
Published: March 2005

Immigration into the UK has increased in response to high labour demand in the recent past. This additional supply of labour has helped keep interest rates lower, and growth higher, than they might have been otherwise. The longer‐term impact of higher immigration may be an increase in trend productivity growth. Although the evidence on such long‐term economic effects is incomplete, there is no reason to believe market principles ‐ or fundamental freedoms ‐ are any less relevant when it comes to flows of people rather than goods or capital.
Activation of nuclear factor‐κB signaling pathway by interleukin‐1 after hypoxia/ischemia in neonatal rat hippocampus and cortex
Authors: Hu Xiaoming , Nesic‐Taylor Olivera , Qiu Jingxin , Rea Harriett C. , Fabian Roderick , Rassin David K. , Perez‐Polo J. Regino
Published: March 2005

Perinatal hypoxia/ischemia (HI) is a common cause of neurological deficits in children. Interleukin‐1 (IL‐1) activity has been implicated in HI‐induced brain damage. However, the mechanisms underlying its action in HI have not been characterized. We used a 7‐day‐old rat model to elucidate the role of nuclear factor‐κB (NF‐κB) activation in HI stimulation of IL‐1 signaling. HI was induced by permanent ligation of the left carotid artery followed by 90 min of hypoxia (7.8% O2). Using ELISA assays, we observed increased cell death and caspase 3 activity in hippocampus and cortex 3, 6, 12, 24 and 48 h post‐HI. IL‐1β protein expression increased, beginning at 3 h after HI and lasting until 24 h post‐HI in hippocampus and 12 h post‐HI in cortex. Intracerebroventricular injection of 2µg IL‐1 receptor antagonist (IL‐1Ra) 2 h after HI significantly reduced cell death and caspase 3 activity. Electrophoretic mobility shift assay analyses of hippocampus and cortex after HI for NF‐κB activity showed increased p65/p50 DNA‐binding activity at 24 h post‐HI. Western blot analyses showed significant nuclear translocation of p65. Protein expression levels of two known inflammatory agents, inducible nitric oxide synthase and cycloxygenase 2, known to be transcriptionally regulated by NF‐κB, also increased at 24 h after HI. All these HI‐induced changes were reversed by IL‐1Ra blockade of IL‐1 signaling, consistent with IL‐1 triggering of inflammatory apoptotic outcomes via NF‐κB transcriptional activation. The observed increase in cytoplasmic phosphorylated inhibitor κBα (IκBα) and nuclear translocation of Bcl‐3 24 h after HI was also significantly attenuated by IL‐1Ra blockade, suggesting that HI‐induced IL‐1 activation of NF‐κB is via both the degradation of IκBα and the nuclear translocation of Bcl‐3.
M opsin phosphorylation in intact mammalian retinas
Authors: Liu Peng , Osawa Shoji , Weiss Ellen R.
Published: March 2005

The deactivation of visual pigments involved in phototransduction is critical for recovering sensitivity after exposure to light in rods and cones of the vertebrate retina. In rods, phosphorylation of rhodopsin by rhodopsin kinase (GRK1) and the subsequent binding of visual arrestin completely terminates phototransduction. Although signal termination in cones is predicted to occur via a similar mechanism as in rods, there may be differences due to the expression of related but distinct gene products. While rods only express GRK1, cones in some species express only GRK1 or GRK7 and others express both GRKs. In the mouse, cone opsin is phosphorylated by GRK1, but this has not been demonstrated in mammals that express GRK7 in cones. We compared cone opsin phosphorylation in intact retinas from the 13‐lined ground squirrel (GS) and pig, cone‐ and rod‐dominant mammals, respectively, which both express GRK7. M opsin phosphorylation increased during continuous exposure to light, then declined between 3 and 6 min. In contrast, rhodopsin phosphorylation continued to increase during this time period. In GS retina homogenates, anti‐GS GRK7 antibody blocked M opsin phosphorylation by 73%. In pig retina homogenates, only 20% inhibition was observed, possibly due to phosphorylation by GRK1 released from rods during homogenization. Our results suggest that GRK7 phosphorylates M opsin in both of these mammals. Using an in vitro GTPγS binding assay, we also found that the ability of recombinant M opsin to activate Gt was greatly reduced by phosphorylation. Therefore, phosphorylation may participate directly in the termination of phototransduction in cones by decreasing the activity of M opsin.
THE DISTRIBUTION OF WEALTH IN CANADA
Authors: Oja Gail
Published: March 2005

For estimates of the wealth distribution Canada depends on household surveys taken at 6–7 year intervals. The latest data from this source refer to household balance sheets in the spring of 1977. A comparison with 1970 shows that there is little change in the composition of wealth held by households but that inequality of the wealth distribution has been somewhat reduced. Wealth data by age of family head is presented in order to describe more fully the wealth distribution and composition in Canada.

Weaknesses in the data are discussed as well as the difficulties of making appropriate adjustments to the data at the micro record level. For policy evaluation and formulation purposes the lack of comprehensive estimates inclusive of pension wealth as well as the small sample size (12,700 usable records) have been perceived as greater obstacles to utilizing the data than the underestimate in aggregate assets and debts which affects more the higher than the middle and lower ranges of the wealth distribution.
DETERMINANTS OF BANK HOLDING COMPANY DEBT RATINGS
Authors: Billingley Randall S. , Fraser Donald R.
Published: March 2005

Abstract

This paper reports on the construction of a multiple discriminant analysis model which explains the specific ratings assigned by Standard and Poor's Corporation to bank holding company (BHC) capital notes and debentures. It thus investigats the ratings of debt securities issued by banking organizations, an area largely ignored in bond rating research to date. Improving on the methodology of current research concerning BHC bond ratings, the model is 78.5 percent accurate in initially classifying the top three rating categories—AAA, AA, and A. Lachenbruch validation finds the model to be 64.6 percent accurate. Size, variability of net income, the economic environment of the issuing BHC, and the amount and composition of total capital appear to be the principal variables allowing successful discrimination among the debet issue ratings.
AN ANALYTICAL MODEL OF THE RELATIONSHIP BETWEEN MATURITY AND BONDS RISK DIFFERENTIALS
Authors: Chiang Raymond , Kolb Robert W.
Published: March 2005

This paper extends previous analyses of bond risk differentials by relaxing the key assumption of a constant probability of firm survival. Under the less restrictive assumption that firm income is stationary and independent over time, it is shown that risk differential clearly varies with maturity even with a flat term structure. Because the payoff possibilities of multi‐period bonds are interdependent even though income in each period is independent, risk differentials must depend on maturity, even if term structure is flat. This conclusion is more compatible with empirical findings than were conclusions of previous analyses.
TESTING PRICE TAKING IN LOAN AND DEPOSIT MARKETS BY FINANCIAL FIRMS
Authors: Hancock Diana
Published: March 2005

This paper tests for the failure of price taking in the markets for financial and nonfinancial services. A firm that can purchase or sell an unlimited quantity at the prevailing price is a price taker. This hypothesis is tested using historical data on a sample of eighteen banks, considering financial services, demand deposits, time deposits, labor, cash, materials, and capital. The empirical results indicate little flexibility in the financial technology, whether price taking is imposed on all markets or only on the labor market.
STATISTICAL TESTS OF THE ACCURACY OF ALTERNATIVE FORECASTS: SOME RESULTS FOR U.S. UTILITY BETAS
Authors: Kryzanowski Lawrence , Jalilvand Abolhassan
Published: March 2005

The common approach for assessing the relative forecast accuracy of various predictors is simply to compare their simple ranks based on some measure(s) of forecast accuracy (such as the mean square errors). However, conventional methodologies for conducting a t‐test or F‐test of forecast accuracy are inappropriate and unreliable. A statistical methodology is proposed in this paper that rectifies most of the problems involved with conducting such conventional tests of statistical significance. Using this statistical methodology on the mean square errors of six beta predictors for five forecast horizons for fifty utilities, it was found that there are statistically significant differences between the forecast accuracies of the beta predictors for each and every forecast horizon, that the statistical rankings of the beta predictors were significantly different from and more congruent than the simple rankings as the forecast horizon lengthened, and that the ordinary least squares predictor was consistently ranked as one of the poorest beta predictors for all of the forecast horizons.
PREFERRED STOCK ARBITRAGE OF MUNICIPAL BOND MARKET SEGMENTATION
Authors: Elmer Peter J.
Published: March 2005

This paper discusses how tax and regulatory constraints in the municipal bond market can affect preferred stock yields and give rise to arbitrage opportunities in the preferred stock market. The potential for profit is illustrated with an example that also serves to highlight the unique characteristics of recently developed forms of preferred stock.
THE ANALYTICS OF TAX EFFECTS IN DISCOUNT BOND VALUATION
Authors: Stock Duane
Published: March 2005

This paper discusses the analytics of tax effects in discount bond valuation. The author illustrates that bond value is a simple linear function of the tax rate on interest income, whereas bond value is concave to the capital gains tax rate. The author also analyzes how changes in tax rates interact with yield changes to affect bond valuation and how tax rates interact with maturity to determine the depth of bond discount.
MARKET EFFECTS OF CHANGES IN THE STANDARD & POOR'S 500 INDEX
Authors: Lamoureux Christopher G. , Wansley James W.
Published: March 2005

This paper examines the impact on stock returns of changes in the Standard & Poor's (S&P) 500 index. S&P states that firms are not added to or deleted from the index for valuation reasons but rather to maintain or improve the index's representative character. Results from market response tests indicate that stocks added to (deleted from) the index since 1975 experience a significant positive (negative) announcement day excess return. No announcement effect occurs in S&P changes prior to 1976. These announcement effects may be explained by a price‐pressure hypothesis or by an information effect. Results of tests conducted to isolate which of these phenomena is present are reported.
AIRLINE DEREGULATION AND THE PROBABILITY OF AIR CARRIER INSOLVENCY
Authors: Michel Allen , Shaked Israel
Published: March 2005

This study investigates the effects of deregulation from the perspective of airline lenders. Airline‐specific, pre‐ and post‐deregulation insolvency probabilities are used to assess the effects on creditors. The results suggest that the financial condition of several airlines has significantly deteriorated as a by‐product of deregulation, although most have been unaffected.
AN EXCHANGE RATIO DETERMINATION MODEL FOR MERGERS: A NOTE
Authors: Yagil Joseph
Published: March 2005

One of the most important financial and economic issues involved in corporate mergers is the determination of the exchange ratio between the shares of the acquiring firm and the acquired firm. The model presented in theis paper is based on the dividend growth model. Since growth expectations are crucial in an exchange ratio negotiation, the model derived here, which explicitly incorporates these growth expectations, is relevant. In contrast, Larson and Gonedes' exchange ratio expressions are in terms of price‐earnings multiples. The model presented here provides an exchange ratio expression for the buying firm and one for the selling firm. Both expressions are a function of one variable—the post‐merger growth rate as perceived by each party. There are two important features of the model: (1) it provides boundary values for negotiation; and (2) it can be used to study the effect of firm characteristics on the bid‐and‐asked exchange ratios.
TRADING TIME EFFECTS IN FINANCIAL AND COMMODITY FUTURES MARKETS
Authors: Ferris Stephen P. , Chance Don M.
Published: March 2005

Through the examination of one commodity contract, soybeans, and one financial contract, U.S. Treasury bonds, the authors test to determine (1) whether mean rates of return during trading times differ from mean rates of return during nontrading times; (2) whether mean returns during trading times and nontrading times differ by day of the week; (3) whether trading time returns differ significantly from previous nontrading time returns; and (4) the extent to which trading and previous nontrading returns are correlated. In addition, the authors empirically examine a possible explanation for the results obtained.
INVESTMENT PERFORMANCE OF COMMON STOCKS IN RELATION TO INSIDER OWNERSHIP
Authors: Kim Wi Saeng , Lee Jae Won , Francis Jack Clark
Published: March 2005

In this paper, the authors empirically examine whether corporations with high degrees of insider ownership enjoy superior returns compared with firms with more diffuse ownership. In addition, the authors evaluate the effects of insider ownership on security returns in relations to the well‐known effects of size and earnings yield (or price‐earnings) ratios. Results indicate that, in addition to Basu's price‐earnings effect, insider ownership is a new statistically significant variable that is associated with abnormal returns. This return anomaly might occur because the market pays an inadequate price for top managements' equity ownership, a firm‐specific fundamental variable that has a theoretical foundation in agency theory.
BIAS IN JOURNAL RATINGS
Authors: Cudd Mike , Morris Joe
Published: March 2005

The present study investigated the association between faculty publication records and their point‐based evaluations of finance journals. No relationship was detected between the merit points assigned to finance journals and the journal‐specific success of the faculty rendering the journal ratings. However, a negative relationship was found between general publication success of faculty and the merit points they assigned to lower‐level journal publications. The association was particularly strong for faculty who had published in the top three finance journals.
THE EXCESS RETURN ARGUMENT AND DOUBLE LEVERAGE
Authors: Beranek William , Miles James A.
Published: March 2005

The excess return argument is widely accepted as the most compelling plea in favor of the double leverage method of assessing the cost of capital for certain utilities. The argument is shown to be mistaken. Moreover, only under unlikely conditions does the double leverage method assess the cost of capital correctly. The stand alone method, according to generally accepted financial theory, is a superior procedure.
FINANCIAL PLANNING AND CONTROL FOR COMMERCIAL AND INDUSTRIAL ENTERPRISES IN CHINA
Authors: Jen Frank C.
Published: March 2005

Financial planning and control systems in China are discussed. The effectiveness of the pre‐1979 system is evaluated and compared to the system instituted in 1979 under China's modernization drive. The implications of these changes for China and for the United States are discussed.
THE IMPACTS OF FINANCIAL DEREGULATION UPON TRADING EFFICIENCY AND THE LEVELS OF RISK AND RETURN OF JAPANESE BANKS
Authors: Pettway Richard H. , Tapley T. Craig , Yamada Takeshi
Published: March 2005

Japanese banks are very large and were rigidly controlled until financial deregulation began in the late 1970s. This paper measures the impact of deregulation upon the trading efficiency and the levels of risk and return of the largest 27 listed Japanese banks. We found that as the pace of deregulation increased, there were significant increases in trading efficiency as well as in the levels of returns and risks. With deregulation, the Japanese banking system, which contains the largest banks in the world, has become less protected and more vulnerable to the discipline of market movements.
DISINTERMEDIATION REVISITED
Authors: Horvath Philip A.
Published: March 2005

The passage of financial institution reform legislation such as the Depository Institution Deregulation and Monetary Control Act of 1980 is thought to reduce disintermediation. This paper shows that the prevailing “mean difference” explanation for disintermediation is insufficient. Furthermore, this paper shows that two‐moment expected utility explains depositors' mixing behavior but does not fully explain disintermediation. Maximization of expected utility in the form of a power function is used to show that skewness in expectations explains the shifts from thrift deposits that characterize disintermediation.