bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assessing the effects of age, sex and shared environment on the genetic aetiology of depression in childhood and adolescence
Authors: Rice Frances , Harold Gordon T. , Thapar Anita 
Published: March 2003

Background:  Depressive symptoms and disorder are experienced by a significant proportion of young people and have long‐lasting deleterious effects. The aims of the current investigation were to examine the aetiology of depressive symptoms using a twin design. In particular to examine the effects of sex, age, maternal depression and anxiety symptoms and to examine the aetiology of high depression scores.Methods: Questionnaires were sent to the families of a population‐based sample of twins aged between 8 and 17 years. Parents and children over the age of 11 were asked to complete the Mood and Feelings Questionnaire and Hospital Anxiety and Depression Scale (mothers only). Responses were obtained from 1463 families and data were analysed using genetic model fitting and DeFries and Fulker regression analysis.Results: Depressive symptoms, particularly when self‐rated, were significantly genetically influenced. There was evidence of significant heterogeneity according to age, with shared environmental factors more important and genetic factors less important for children aged 8 to 10 than for adolescents aged 11 to 17 years. Some but not all of the shared environmental influences on parent‐rated depressive symptoms were accounted for by maternal symptoms of depression and anxiety. There was a significant effect of gender for self‐rated depressive symptoms. For boys, genetic factors were of greater importance and common environmental influences of less importance than for girls. Shared environmental effects had a substantial influence on high self‐rated depression scores. Adolescents who scored highly on self‐rated depression questionnaires experienced significantly more shared life events and their mothers had significantly higher internalising symptoms than adolescents who scored within the normal range.Conclusions: The results of this study add to the evidence that the aetiology of depressive symptoms differs by age, with genetic factors becoming more important from childhood to adolescence. Some but not all of the shared environmental effect observed for mother‐rated depression scores is due to maternal depression and anxiety symptoms. For self‐rated depressive symptoms, the importance of genetic and environmental factors may also differ by sex, with genetic influences more important for boys. The aetiology of high depression symptom scores, when self‐rated, appears to differ from scores within the normal range in that shared environmental factors appear to be more important. Further research is needed to identify these shared environmental factors using longitudinal models that test genetic and environmental mediation.
Optimal Location of Deep‐Sea Tsunami Detectors
Authors: Braddock R. D. , Carmody O. 
Published: March 2003

The development of deep‐sea detectors has significantly enhanced the potential for tsunami detection, particularly in the Pacific region. The detectors work in combination with satellite communication technology and surface communication buoys to provide an efficient and effective warning technology. The objective of this study is to identify the optimal distribution of a limited number of detectors, given that a maximum of six potential buoy sites has already been determined. Two objective functions are developed, one for a Pacific‐wide warning potential, and the second a more specific USA warning potential. The resulting non‐linear 0‐1 integer‐programming problems are readily solved using enumeration techniques.The results conclude that three detectors in the Tsunami Warning System can achieve the maximum warning potential for both the Pacific region and the USA.
Managerial Actions, Stock Returns, and Earnings: The Case of Business‐to‐Business Internet Firms
Authors: Rajgopal Shivaram , Venkatachalam Mohan , Kotha Suresh 
Published: March 2003

In this study we investigate the valuation implications of managerial actions undertaken by 57 Internet firms engaged in Business‐to‐Business (B2B) e‐commerce. We classify 3,007 managerial actions undertaken by our sample firms between the firm’s IPO date and September 30, 2000 into nine action categories: (1) acquisition of major customers, (2) introduction of new products and services, (3) promotional and marketing actions, (4) actions taken to address the concerns of stakeholders such as employees and the community at large, (5) announcements of technology, marketing, and distribution alliances, (6) completion of acquisitions, (7) expansion into international markets, (8) management team building actions, and (9) organizational changes.In the short window tests, we find a significant increase in stock price volatility over a three‐day event window surrounding the announcement of almost all actions suggesting that announcement of managerial actions provides value‐relevant information to the stock market. In the long window tests, we use factor analysis to group the counts of managerial actions taken by each firm over its post‐IPO life into two broad managerial initiatives—market penetration and organization building. These two initiatives explain a substantial portion of the cross‐sectional variation in the firms’ post‐IPO life stock market returns beyond that explained by both reported earnings and analysts’ forecasts of future earnings and revenues. Thus, investors appear to supplement relatively meager accounting information with data about the cross‐sectional intensity of managerial actions in setting stock prices of B2B Internet firms.
What Drives Stock Price Behavior Following Extreme One‐Day Returns
Authors: Larson Stephen J. , Madura Jeff 
Published: March 2003

AbstractWe identify samples of losers and winners by selecting daily stock price returns in excess of 10% (sign ignored) and determine whether these samples over‐ or underreact. We then identify “informed” events, which correspond to announcements in the Wall Street Journal(WSJ), and “uninformed” events, which are not explained in the WSJ. For winners, there is overreaction in response to uninformed events but no overreaction on average in response to informed events. This finding suggests the degree of overreaction to new information depends on whether the cause of the extreme stock price change is publicly released.
Abstract
Authors: Hauser‐Cram Penny , Warfield Marji Erickson , Shonkoff Jack P. , Krauss Marty Wyngaarden 
Published: March 2003

This Monograph presents the results of the Early Intervention Collaborative Study, a longitudinal investigation of the cognitive and adaptive behavior development of children with developmental disabilities and the adaptation of their parents, extending from infancy through middle childhood. The study was designed to generate and test conceptual models of child and family development and contribute to the knowledge base that informs social policy and practice.The sample for the investigation reported here consists of 183 children with Down syndrome, motor impairment, developmental delay and their families who were recruited at the time of their enrollment in an early intervention program in Massachusetts or New Hampshire. Data were collected at five time points between entry to early intervention and the child's 10th birthday. Home visits were conducted at each time point and included child assessments, maternal interview, and questionnaires completed independently by both parents.Trajectories in children's development and parental well‐being were analyzed using hierarchical linear modeling. Predictor variables were measured at age 3 years when children were exiting early intervention programs. Children's type of disability predicted trajectories of development in cognition, social skills, and daily living skills. Children's type of disability also predicted changes in maternal (but not paternal) child‐related and parent‐related stress. Beyond type of disability, child self‐regulatory processes (notably behavior problems and mastery motivation) and one aspect of the family climate (notably mother‐child interaction) were key predictors of change in both child outcomes and parent well‐being. A different aspect of the family climate—family relations—also predicted change in child social skills. Parent assets, measured as social support and problem‐focused coping, predicted change in maternal and paternal parent‐related stress respectively.The implications of these findings for both the science of child development and the policies and practices of developmental intervention are discussed.
Project Management Characteristics and New Product Survival
Authors: Jeffrey Thieme R. , Michael Song X. , Shin Geon‐Cheol 
Published: March 2003

We develop a conceptual model of new product development (NPD) based on seminal and review articles in order to answer the question, “What project management characteristics will foster the development of new products that are more likely to survive in the marketplace?” Our model adopts Ruekert and Walker's theoretical framework of situational dimensions, structural/process dimensions, and outcome dimensions as an underlying structure. We conceptualize their situational dimensions more narrowly as project management dimensions, allowing us to examine more specifically how project management practices affect the NPD process. In our model, project management dimensions include project manager style, project manager skills, and senior management support. Structural/process dimensions include cross‐functional integration and planning proficiency. Outcome dimensions include process proficiency and new product survival.Our empirical analysis finds support for 20 hypotheses, a reversal of one hypothesis, and nonsignificant results for one hypothesis. These results show that projects are best led by managers with strong technical, marketing, and management skills, using a participative style and enjoying early and continuous support from senior management. These project management dimensions promote cross‐functional integration and planning, which are important to process proficiency and new product survival.Our study suggests two broad conclusions. First, it confirms the links in the extant literature between situational (project management) dimensions, structural/process dimensions, and outcome dimensions in NPD. Second, firms can improve cross‐functional integration and planning through various project management practices. Generally, we find that firms interested in improving both proficiency in their development process and the survival rate of new products should take steps to promote cross‐functional integration and to improve their planning processes. While the linkage between cross‐functional integration and NPD outcomes is well established in the literature, the impact of the planning process on NPD outcomes is a research area ripe with opportunity. Our study highlights three aspects of planning that contribute to NPD outcomes. Plans should be detailed, team members should participate actively in the planning process, and teams should be given flexibility and autonomy to respond to unanticipated issues as they appear.
The Cadbury Committee, Corporate Performance, and Top Management Turnover
Authors: Dahya Jay , McConnell John J. , Travlos Nickolaos G. 
Published: March 2003

ABSTRACTIn 1992, the Cadbury Committee issued the Code of Best Practice which recommends that boards of U.K. corporations include at least three outside directors and that the positions of chairman and CEO be held by different individuals. The underlying presumption was that these recommendations would lead to improved board oversight. We empirically analyze the relationship between CEO turnover and corporate performance. CEO turnover increased following issuance of the Code; the negative relationship between CEO turnover and performance became stronger following the Code's issuance; and the increase in sensitivity of turnover to performance was concentrated among firms that adopted the Code.
The Long‐run Performance Following Dividend Initiations and Resumptions: Underreaction or Product of Chance?
Authors: Boehme Rodney D. , Sorescu Sorin M. 
Published: March 2003

ABSTRACTWe examine the long‐term stock performance following dividend initiations and resumptions from 1927 to 1998. We show that postannouncement abnormal returns are significantly positive for equally weighted calendar time portfolios, but become insignificant when the portfolios are value weighted. Moreover, the equally weighted results are not robust across subsamples. We also document postannouncement reductions in the risk factor loadings of underlying stocks. Cross‐sectionally, these reductions are negatively related to the contemporaneous price drifts, suggesting the price drifts may be a sample‐specific result of chance. Our results underscore the importance of testing for changes in risk loadings in future long‐term event studies.
Is Disinflation Good for the Stock Market?
Authors: Henry Peter Blair 
Published: March 2003

ABSTRACTThe stock market appreciates by an average of 24 percent in real dollar terms when countries attempt to stabilize annual inflation rates that are greater than 40 percent. In contrast, the average market response is 0 when the prestabilization rate of inflation is less than 40 percent. These results suggest that the potential long‐run benefits of stabilization may dominate shortrun costs at high levels of inflation, but at low to moderate levels of inflation, benefits may be offset by costs in a present value sense. Stock market responses also help predict the change in inflation and output in the year following all 81 stabilization efforts.
Do Bonds Span the Fixed Income Markets? Theory and Evidence for Unspanned Stochastic Volatility
Authors: Collin‐Dufresne Pierre , Goldstein Robert S. 
Published: March 2003

ABSTRACTMost term structure models assume bond markets are complete, that is, that all fixed income derivatives can be perfectly replicated using solely bonds. How ever, we find that, in practice, swap rates have limited explanatory power for returns on at‐the‐money straddles—portfolios mainly exposed to volatility risk. We term this empirical feature unspanned stochastic volatility (USV). While USV can be captured within an HJM framework, we demonstrate that bivariate models cannot exhibit USV. We determine necessary and sufficient conditions for trivariate Markov affine systems to exhibit USV. For such USV models, bonds alone may not be sufficient to identify all parameters. Rather, derivatives are needed.
Distinct Mechanisms of Neutralization by Monoclonal Antibodies Specific for Sites in the N-Terminal or C-Terminal Domain of Murine Leukemia Virus SU
Authors: Burkhart Michael Dominic , Kayman Samuel C. , He Yuxian , Pinter Abraham 
Published: March 2003

ABSTRACT
The epitope specificities and functional activities of monoclonal antibodies (MAbs) specific for the murine leukemia virus (MuLV) SU envelope protein subunit were determined. Neutralizing antibodies were directed towards two distinct sites in MuLV SU: one overlapping the major receptor-binding pocket in the N-terminal domain and the other involving a region that includes the most C-terminal disulfide-bonded loop. Two other groups of MAbs, reactive with distinct sites in the N-terminal domain or in the proline-rich region (PRR), did not neutralize MuLV infectivity. Only the neutralizing MAbs specific for the receptor-binding pocket were able to block binding of purified SU and MuLV virions to cells expressing the ecotropic MuLV receptor, mCAT-1. Whereas the neutralizing MAbs specific for the C-terminal domain did not interfere with the SU-mCAT-1 interaction, they efficiently inhibited cell-to-cell fusion mediated by MuLV Env, indicating that they interfered with a postattachment event necessary for fusion. The C-terminal domain MAbs displayed the highest neutralization titers and binding activities. However, the nonneutralizing PRR-specific MAbs bound to intact virions with affinities similar to those of the neutralizing receptor-binding pocket-specific MAbs, indicating that epitope exposure, while necessary, is not sufficient for viral neutralization by MAbs. These results identify two separate neutralization domains in MuLV SU and suggest a role for the C-terminal domain in a postattachment step necessary for viral fusion.
Unusual Properties of Adenovirus E2E Transcription by RNA Polymerase III
Authors: Huang Wenlin , Flint S. J. 
Published: March 2003

ABSTRACT

In adenovirus type 5-infected cells, RNA polymerase III transcription of a gene superimposed on the 5′ end of the E2E RNA polymerase II transcription unit produces two small (<100-nucleotide) RNAs that accumulate to low steady-state concentrations (W. Huang, R. Pruzan, and S. J. Flint, Proc. Natl. Acad. Sci. USA 91:1265-1269, 1984). To gain a better understanding of the function of this RNA polymerase III transcription, we have examined the properties of the small E2E RNAs and E2E RNA polymerase III transcription in more detail. The accumulation of cytoplasmic E2E RNAs and the rates of E2E transcription by the two RNA polymerases during the infectious cycle were analyzed by using RNase T
1
protection and run-on transcription assays, respectively. Although the RNA polymerase III transcripts were present at significantly lower concentrations than E2E mRNA throughout the period examined, E2E transcription by RNA polymerase III was found to be at least as efficient as that by RNA polymerase II. The short half-lifes of the small E2E RNAs estimated by using the actinomycin D chase method appear to account for their limited accumulation. The transcription of E2E sequences by RNA polymerase II and III in cells infected by recombinant adenoviruses carrying ectopic E2E-CAT (chloramphenicol transferase) reporter genes with mutations in E2E promoter sequences was also examined. The results of these experiments indicate that recognition of the E2E promoter by the RNA polymerase II transcriptional machinery in infected cells limits transcription by RNA polymerase III, and vice versa. Such transcriptional competition and the properties of E2E RNAs made by RNA polymerase III suggest that the function of this viral RNA polymerase III transcription unit is unusual.
Tumor Necrosis Factor Alpha Inhibition of Hepatitis B Virus Replication Involves Disruption of Capsid Integrity through Activation of NF-κB
Authors: Biermer Michael , Puro Robyn , Schneider Robert J. 
Published: March 2003

ABSTRACTChronic infection by hepatitis B virus results from an inability to clear the virus, which is associated with liver disease and liver cancer. Tumor necrosis factor alpha (TNF-α) is associated with noncytopathic clearance of hepatitis B virus in animal models. Here we demonstrate that the nuclear factor κB (NF-κB) signaling pathway is a central mediator of inhibition of hepatitis B virus by TNF-α and we describe the molecular mechanism. TNF-α is shown to suppress hepatitis B virus DNA replication without cell killing by disrupting the formation or stability of cytoplasmic viral capsids through a pathway requiring the NF-κB-activating inhibitor of κB kinase complex IKK-α/β and active transcription factor NF-κB. Hepatitis B virus replication could also be inhibited and viral capsid formation could be disrupted in the absence of TNF-α solely by overexpression of IKK-α/β or strong activation of NF-κB. In contrast, inhibition of NF-κB signaling stimulated viral replication, demonstrating that HBV replication is both positively and negatively regulated by the level of activity of the NF-κB pathway. Studies are presented that exclude the possibility that HBV inhibition by NF-κB is carried out by secondary production of gamma interferon or alpha/beta interferon. These results identify a novel mechanism for noncytopathic suppression of hepatitis B virus replication that is mediated by the NF-κB signaling pathway and activated by TNF-α.
Characterization of Human Class-Switched Polymeric (Immunoglobulin M [IgM] and IgA) Anti-Human Immunodeficiency Virus Type 1 Antibodies 2F5 and 2G12
Authors: Wolbank Susanne , Kunert Renate , Stiegler Gabriela , Katinger Hermann 
Published: March 2003

ABSTRACTWe have previously generated human monoclonal anti-human immunodeficiency virus type 1 (anti-HIV-1) antibodies 2F5IgG and 2G12IgG with an exceptional cross-clade neutralizing potential. 2F5IgG and 2G12IgG passively administrated to macaques were able to confer complete protection from both intravenous and mucosal challenge with pathogenic HIV-simian immunodeficiency virus chimeric strains and have shown beneficial effects in a phase-1 clinical trial. We now class-switched 2F5 and 2G12 to the immunoglobulin M (IgM) or IgA isotype, to enforce features like avidity, complement activation, or the potential to neutralize mucosal transmission. For this purpose we expressed functional polymeric 2F5 and 2G12 antibodies in CHO cells and evaluated their anti-HIV-1 activity in vitro. The class switch had a strong impact on the protective potential of 2F5 and 2G12. 2G12IgM inhibited HIV-1 infection of peripheral blood mononuclear cell cultures up to 28-fold-more efficiently than the corresponding IgG and neutralized all of the primary isolates tested. The 2F5 and 2G12 antibodies of all isotypes were able to interact with active human serum to inhibit viral infection. Furthermore, we demonstrated that polymeric 2F5 and 2G12 antibodies but not the corresponding IgGs could interfere with HIV-1 entry across a mucosal epithelial layer in vitro. Although polymeric 2F5 antibodies had only limited potential in the standard neutralization assay, the results from the mucosal assay suggest that 2F5 and 2G12 antibodies may have a high potential to prevent natural HIV-1 transmission in vivo.