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Acquisition
Kinds of Acquisition Terms modified by Acquisition Selected AbstractsADAPTATION KNOWLEDGE ACQUISITION: A CASE STUDY FOR CASE-BASED DECISION SUPPORT IN ONCOLOGYCOMPUTATIONAL INTELLIGENCE, Issue 3-4 2006Mathieu D'Aquin Kasimir is a case-based decision support system in the domain of breast cancer treatment. For this system, a problem is given by the description of a patient and a solution is a set of therapeutic decisions. Given a target problem, Kasimir provides several suggestions of solutions, based on several justified adaptations of source cases. Such adaptation processes are based on adaptation knowledge. The acquisition of this kind of knowledge from experts is presented in this paper. It is shown how the decomposition of adaptation processes by introduction of intermediate problems can highlight simple and generalizable adaptation steps. Moreover, some adaptation knowledge units that are generalized from those acquired for Kasimir are presented. This knowledge can be instantiated in other case-based decision support systems, in particular in medicine. [source] WITHOUT CONSENT: PRINCIPLES OF JUSTIFIED ACQUISITION AND DUTY-IMPOSING POWERSTHE PHILOSOPHICAL QUARTERLY, Issue 237 2009Hugh Breakey A controversy in political philosophy and applied ethics concerns the validity of duty-imposing powers, that is, rights entitling one person to impose new duties on others without their consent. Many philosophers have criticized as unplausible any such moral right, in particular that of appropriating private property unilaterally. Some, finding duty-imposing powers weird, unfamiliar or baseless, have argued that principles of justified acquisition should be rejected; others have required them to satisfy exacting criteria. I investigate the many ways in which we regularly impose duties on one another without prior consent. I show that doing so is not weird, and I offer criteria which demarcate the reasonable from the worrisome aspects of duty-imposing powers. [source] Operative Platform Applied to Building AutomationCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 1 2009João Figueiredo This structure is composed by three interrelated levels: the Operational level,where the field equipment is controlled, the Inter-Active level,where inhabitants communicate the building their preferences regarding control variables (lights, temperature, etc.), and the higher-level control, the Overall Building Well-Being Model, which manages the global building, taking into account the optimization of the inhabitants preferences, constrained by the available resources. At this third level, the inter-building communication is available. Each building has the capability to communicate with its neighbors, informing about fires, floods, security problems, power consumption expectations, and so on. This article implements one of the three above-referred interrelated control levels: the Operational-level control. This operative platform is structured over a cascade hierarchical control architecture where inner loops are performed by local PLCs (Programmable Logic Controllers), and the outer loop is managed by a centralized SCADA system (Supervisory Control and Data Acquisition) that interacts with the entire PLC network. The lower-level control loop assures high processing velocity tasks, the upper-level control loop updates the local references, knowing the complete system state. This operative model is tested on two prototypes, where all instrumentation in place is controlled by the industrial PLC network. Both prototypes worked perfectly showing the huge potential of communication systems between distributed processes. These communication systems allow intelligent centralized algorithms to manage decision-making problems in real-time environments. The system presented in this article combines several technologies (local PLCs, SCADA systems, and network communications) to reach the goal of efficient management of intelligent buildings. [source] Road Infrastructure Data Acquisition Using a Vehicle-Based Mobile Mapping SystemCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 5 2006Gi-Hong Kim The mobile mapping system that integrates the global positioning system (GPS), the inertial navigation system (INS), and digital cameras has been developed to collect data on position and attributes of road infrastructure. The vehicle-based mobile mapping system works by having the GPS and INS record the position and attitude data, and digital cameras take road images. The stereovision system can determine the position of objects that are visible on the image pair in the global coordinate system with GPS and INS data. As field data acquisition is a very expensive task, a mobile mapping system offers a greatly improved solution. In this study, we successfully created a road infrastructure map with mobile mapping technology and proposed automatic algorithms for detecting and identifying road signs from road images. The proposed detection algorithm includes line and color region extraction processes and uses the Hopfield neural networks. The identification algorithm uses seven invariant moments and parameters that present geometric characteristics. With this combined method, we could successfully detect and identify road signs. [source] A Transdisciplinary Approach to Conservation Land AcquisitionCONSERVATION BIOLOGY, Issue 6 2002Brian Czech I integrated principles of conservation biology, ecological economics, and political science to outline an approach to conservation land acquisition in the United States. American political economy, especially, has profound implications for conservation land acquisition, yet these implications have been largely neglected by public land conservation agencies. I derived three general recommendations for the conservation of biodiversity via land acquisition: (1) relatively inexpensive lands in relatively intact ecosystems should be prioritized for acquisition, (2) fee-title acquisition should be favored over easement acquisition, and (3) low-lying coastal properties should receive lower priority. These recommendations contribute to an ecologically macroeconomic approach to conservation land acquisition, and each will become more appropriate as the sizes of the U.S. and global economies increase. Ultimately, however, the conservation of biodiversity will require a new political economy predicated on sustainability rather than growth. Resumen: La adquisición de tierras es uno de los aspectos claves para la conservación de la biodiversidad y es una empresa transdisciplinaria que requiere de la consideración de fenómenos sociales y naturales. Integré los principios de la biología de la conservación, la economía ecológica y las ciencias políticas para desarrollar una metodología de adquisición de tierras para la conservación en los Estados Unidos. La economía política norteamericana, especialmente tiene implicancias profundas sobre la adquisición de tierras para la conservación, sin embargo, estas aplicaciones han sido negadas ampliamente por las agencias de conservación de tierras públicas. Derivé tres recomendaciones generales para la conservación de la biodiversidad mediante la adquisición de tierras: 1) tierras relativamente baratas en ecosistemas relativamente intactos deben ser priorizadas para la adquisición, 2) los títulos de adquisición honoraria deben ser favorecidos sobre las adquisiciones forzadas y 3) las propiedades costeras bajas deberán recibir la prioridad más baja. Estas recomendaciones contribuyen a una aproximación ecológicamente macroeconómica para la adquisición de tierras para la conservación y cada una de ellas será más apropiada en tanto que los bienes de los Estados Unidos y la economía global incremente. Sin embargo, a fin de cuentas, la conservación de la biodiversidad requerirá de una nueva economía política predicada en la sustentabilidad más que en el crecimiento. [source] Knowledge Acquisition and Memory Effects Involving an Expert System Designed as a Learning Tool for Internal Control Assessment*DECISION SCIENCES JOURNAL OF INNOVATIVE EDUCATION, Issue 1 2003Mary Jane Lenard ABSTRACT The assessment of internal control is a consideration in all financial statement audits, as stressed by the Statement on Auditing Standards (SAS) No. 78. According to this statement, "the auditor should obtain an understanding of internal control sufficient to plan the audit" (Accounting Standards Board, 1995, p. 1). Therefore, an accounting student will progress through the auditing course with the responsibility of learning how and why internal controls are assessed. Research in expert systems applied to auditing has shown that there is strong support for the constructive dialogue used in expert systems as a means of encouraging their use in decision making (Eining, Jones, & Loebbecke, 1997). The purpose of this study is to provide the student or novice auditor with a method for developing a more comprehensive understanding of internal controls and the use of internal controls in audit planning. The results of the study reinforce previous findings that novices do better when an expert system applies analogies along with declarative explanations, and clarifies the length of time in which the use of active learning in a training system can provide an improvement to declarative knowledge, but procedural knowledge must be acquired over a longer time frame. [source] Brief communication: A randomized study of iterative hypothesis testing in undergraduate psychiatric educationACTA PSYCHIATRICA SCANDINAVICA, Issue 4 2010K. G. Kahl Kahl KG, Alte C, Sipos V, Kordon A, Hohagen F, Schweiger U. A randomized study of iterative hypothesis testing in undergraduate psychiatric education. Objective:, Iterative hypothesis testing (IHT) or related strategies of diagnostic decision making have been taught in many curricula for medical students but not in psychiatry. We therefore asked whether the addition of training in IHT may add to the quality of the psychiatry course. Method:, Seventy-two medical students were randomized to four weeks problem-based learning or to IHT. Knowledge and skills of the students were tested using a multiple choice exam and simulated patients. Results:, Iterative hypothesis testing-trained students recognized more diagnostic items and more often identified comorbid psychiatric disorders and acute suicidal tendencies. Acquisition of general psychiatric knowledge and global satisfaction with the course were similar in both groups. Conclusion:, We conclude that teaching IHT to medical students may enhance their clinical ability to recognize complex disease patterns. Further studies are required concerning the enhancement of clinical skills in the psychiatric specialty. [source] Role of Parasternal Data Acquisition During Contrast Enhanced Real-Time Three-Dimensional EchocardiographyECHOCARDIOGRAPHY, Issue 10 2007Attila Nemes M.D., Ph.D. Background: Recent technical developments have resulted in high-resolution real time three-dimensional echocardiography (RT3DE). The purpose of this study was to investigate the beneficial role of parasternal-acquired images in addition to apical-acquired images during contrast stress RT3DE. Methods: The study comprised 30 consecutive patients (52 ± 11 years, 18 males) with chest pain referred for routine stress testing. The contrast RT3DE images were acquired from the apical and parasternal window with a Sonos 7500 echo system attached to a X4 matrix array transducer. Results: From the apical and parasternal acquisition, 464 segments (91%) and 267 segments (52%) could be analyzed, respectively (P < 0.001). From the apical window, more basal segments were not analyzable (22 of 180, 12% vs. 24 of 330, 7%; P = 0.06). From the parasternal window, more apical segments were not analyzable (117 of 150, 78% vs. 126 of 360, 35%; P < 0.01). The mean image quality index of the 464 analyzable segments from the apical-acquired images was 2.43. Fourteen of 180 basal segments (8%), 12 of 180 midventricular segments (7%) and 2 of 150 apical segment (1%) were only available with parasternal data acquisition. In addition to these 28 segments, 79 segments (15%) already visualized from the apical window improved in quality. The overall mean image quality index, now assessed from 492 (96%) of all segments, using both the apical and parasternal acquired data, improved to 2.74 (P < 0.05). Conclusions: Addition of parasternal to apical acquisition of contrast RT3DE data can decrease the number of nonvisualized segments and improve mean image quality. [source] Concept Acquisition within the Context of an AS Media Studies CourseENGLISH IN EDUCATION, Issue 2 2003Vivien Whelpton Abstract This article explores the means by which students' concept formation can be promoted and outlines findings from an action research project undertaken with a class of 17-year-old AS Media Studies students as a submission for the British Film Institute's MA Certificate in Media Education in 2001. It argues that academic concepts can neither be allowed to develop spontaneously nor be directly taught, but that indirect methods of teacher intervention can be found. It also examines the relationship between thought and language and argues that, while contact with academic discourse can be alienating, its features include a fluency which the handling of complex and abstract ideas requires, particularly in the written mode. The writer suggests that, while this discourse cannot be explicitly taught or learned, modelling techniques may offer a useful approach. [source] Radiological interpretation of the navicular boneEQUINE VETERINARY EDUCATION, Issue 5 2008S. Dyson Summary Acquisition of a sufficient number of high quality radiographic views is an essential prerequisite to accurate radiological interpretation of the navicular bone. This requires appropriate preparation of the foot, careful attention to limb position and to both centring and direction of the x-ray beam, according to hoof capsule conformation. Artefacts are easily created. Potentially significant radiological abnormalities include: entheseiophytes at the proximomedial and proximolateral aspect of the bone; proximal or distal extension of the flexor border of the bone, distal border fragments, 8 or more large and variably shaped distal border radiolucent zones; discrete radiolucent areas in the spongiosa with or without detectable communication with the flexor cortex; new bone at the sagittal ridge; increased thickness of the flexor cortex; sclerosis of the spongiosa; and a bipartite bone. [source] Diagnostic accuracy of digital photography and image analysis for the measurement of foot conformation in the horseEQUINE VETERINARY JOURNAL, Issue 7 2008J. M. WHITE Summary Reasons for performing study: Rigorous evaluation of practicable methods for the objective assessment of foot conformation has not been performed. Objectives: To assess the practicability, precision and accuracy of the process of obtaining measurements of horses' feet using photography and image processing software. Methods: Precision study: Lateral photographs of horses' feet were obtained twice by 2 veterinary surgeons (image acquisition - IAc). Photographs were analysed by 2 masked veterinary surgeons on 2 occasions (image analysis - IAn). Measurements were compared within and between operators for self and non-self acquired photographs. Agreement indices (AIs) and 95% limits of agreement (LOA) were calculated for the IAn process alone and for the combined IAc + IAn processes. Accuracy study: Measurements obtained from lateral photographs were compared with those obtained from lateromedial radiographs. AIs and 95% LOA were calculated for each measurement. Results: Precision study: Mean intra- and interoperator AIs for the IAn process alone were ,0.90 while those for the combined IAc + IAn processes were ,0.89 for all measurements. Similar mean AIs and 95% LOA were calculated regardless of image origin. The 95% LOA for hoof angle, heel height/toe height% and coronary band angle for all comparisons were within target values. Accuracy study: Mean AIs were ,0.89 for all measurements. The 95% LOA for heel height/toe height% and coronary band angle were within target values. Conclusions: Excellent precision was identified within and between operators regardless of image origin. High levels of accuracy were also identified, especially for heel height/toe height% and coronary band angle, indicating that photography and radiography may be used interchangeably. Potential relevance: Acquisition and analysis of photographic images is an appropriate method for the objective measurement of foot conformation, both in clinical and research settings. [source] Acquisition of regulatory function by human CD8+ T cells treated with anti-CD3 antibody requires TNFEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 10 2010Vitaly Ablamunits Abstract Anti-CD3 mAb can modulate graft rejection and attenuate autoimmune diseases but their mechanism(s) of action remain unclear. CD8+ T cells with regulatory function are induced in vitro by Teplizumab, a humanized anti-CD3 antibody and inhibit responses of autologous and allogeneic T cells. They inhibit CD4+ T-cell proliferation by mechanisms involving TNF and CCL4, and by blocking target cell entry into G2/M phase of cell cycle but neither kill them, nor compete for IL-2. CD8+ Treg can be isolated from peripheral blood following treatment of patients with Type 1 diabetes with Teplizumab, but not from untreated patients. The induction of CD8+ Treg by anti-CD3 mAb requires TNF and signaling through the NF-,B cascade. The CD8+ Treg express CD25, glucocorticoid-induced TNF receptor family, CTLA-4, Foxp3, and TNFR2, and the combined expression of TNFR2 and CD25 identifies a potent subpopulation of CD8+ Treg. These studies have identified a novel mechanism of immune regulation by anti-CD3 mAb and markers that may be used to track inducible CD8+ Treg in settings such as chronic inflammation or immune therapy. [source] Education of hyporesponsive NK cells by cytokinesEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 9 2009Kerstin Juelke Abstract NK-cell tolerance to self is mediated via engagement of inhibitory receptors by cognate MHC molecules. This event is critical for NK-cell education to achieve functional competence. Thus, NK cells expressing self-MHC-specific inhibitory receptors are responsive to activating stimuli while those lacking such receptors are hyporesponsive. Nevertheless, the mechanisms underlying NK-cell education are still poorly understood. Here, we show that after stimulation with cytokines, hyporesponsive NK cells acquire stable expression of killer Ig-like receptors (KIR) as reflected by DNA hypomethylation of their KIR locus. Remarkably, only hyporesponsive NK cells that acquire KIR in the presence of their cognate MHC molecule gain functional competence and this process can occur in the absence of any accessory cells. Acquisition of competence does not result in autoreactivity, since acquired KIR are functional and therefore able to inhibit NK-cell cytotoxicity. Our data demonstrate that competent NK cells can be generated by cytokine stimulation, suggesting that NK-cell education might not only be an early event which takes place during NK-cell development but might also occur in the periphery during an immune response. [source] PRECLINICAL STUDY: Acquisition and reinstatement of MDMA-induced conditioned place preference in mice pre-treated with MDMA or cocaine during adolescenceADDICTION BIOLOGY, Issue 4 2009Manuel Daza-Losada ABSTRACT Those who take ecstasy are more likely to consume other drugs than non-users with cocaine abuse being reported by 75.5% of high school student MDMA (± 3,4-methylenedioxymetamphetamine hydrochloride) users. The aim of this work was to evaluate the effects of exposure during adolescence to MDMA, cocaine or to both drugs on the MDMA-induced conditioned place preference (CPP) in adult mice. Animals received two daily administrations of saline, 10 mg/kg of MDMA, 25 mg/kg of cocaine or 10 mg/kg of MDMA plus 25 mg/kg of cocaine over 3 days (from PD28 to 30). Three weeks after pre-treatment, the MDMA-induced CPP procedure was initiated (PD52). Acquisition of CPP was induced with a sub-threshold dose of MDMA (1.25 mg/kg) only in animals treated during adolescence with MDMA alone. Preference was established in all the groups after conditioning with 10 mg/kg of MDMA, while the time required to achieve extinction was longer in those pre-treated with cocaine or MDMA alone (46 and 28 sessions, respectively). Moreover, preference was reinstated with progressively lower priming doses of MDMA in mice pre-treated with MDMA or cocaine alone. These results demonstrate that early exposure to MDMA or cocaine induces long-lasting changes that last until adulthood and modify the response of animals to MDMA. [source] MDMA self-administration in rats: acquisition, progressive ratio responding and serotonin transporter bindingEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2007Susan Schenk Abstract 3,4-Methylenedioxymethamphetamine (MDMA) self-administration has been shown in animals with extensive drug histories, but only a small number of studies have examined high rates of responding maintained by MDMA in previously drug-naïve animals. In the present study, influence of dose (0.25 or 1.0 mg/kg/infusion) on the acquisition of MDMA self-administration was measured during daily 6-h sessions. Dose,effect data were obtained for MDMA (0.25,1.0 mg/kg/infusion) self-administration under a progressive ratio (PR) schedule of reinforcement. The effect of experimenter- or self-administered MDMA on [3H] paroxetine binding in several brain regions was measured. Acquisition of MDMA self-administration was highly variable and not different for 0.25 or 1.0 mg/kg/infusion progressed with approximately 60% of the rats acquiring reliable self-administration during the 15-day test period. The percentage of rats that acquired MDMA self-administration was lower than the percentage of rats that acquired cocaine (0.5 mg/kg/infusion) self-administration, and cocaine self-administration was acquired with a shorter latency. Responding maintained by MDMA was dose dependent, and breakpoints under a PR schedule increased with dose. Radioligand binding and autoradiography demonstrated lower densities of serotonin transporter sites (SERT) in MDMA self-administering rats as compared with controls across brain regions. The reduction in SERT densities was comparable in magnitude to rats treated with experimenter-administered doses of MDMA. These data support the idea that MDMA is a drug with high abuse liability, and long-term self-administration may lead to long-lasting deficits in serotonin neurotransmission. [source] Repeated withdrawal from ethanol impairs acquisition but not expression of conditioned fearEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2003T. L. Ripley Abstract Repeated withdrawal from ethanol impairs acquisition of conditioned fear [Stephens, D.N., Brown, G., Duka, T. & Ripley, T.L. (2001) Eur. J. Neurosci., 14, 2023,2031]. This study further examined the effect of repeated withdrawal from ethanol on the expression and acquisition of fear conditioning. Following training, presentation of a cue associated with footshock (CS+) resulted in a suppression of operant responding for food reinforcement. In different groups, shock thresholds were manipulated to give weak or severe behavioural suppression. Rats were subsequently chronically treated with ethanol-containing liquid diet either continuously (single withdrawal) or with three withdrawal periods (repeated withdrawal). Ethanol treatment and withdrawal had no effect on conditioned suppression of responding tested 2 weeks after the final withdrawal, at either shock intensity. Nevertheless, extinction of conditioned fear was impaired in the repeated withdrawal group exposed to the higher shock intensity. In the high intensity group, the stimulus,shock association was then reversed, so that the previously neutral conditioned stimulus (CS,) became the CS+. Acquisition of suppression to the new CS+ was significantly less in the animals previously given repeated experience of withdrawal, confirming our previous finding. Thus, repeated withdrawal from ethanol lead to disruption in the acquisition of fear conditioning but had no effect on retrieval of an association formed prior to the ethanol-withdrawal experiences. [source] Evolution of peptidoglycan biosynthesis under the selective pressure of antibiotics in Gram-positive bacteriaFEMS MICROBIOLOGY REVIEWS, Issue 2 2008Jean-Luc Mainardi Abstract Acquisition of resistance to the two classes of antibiotics therapeutically used against Gram-positive bacteria, the glycopeptides and the ,-lactams, has revealed an unexpected flexibility in the peptidoglycan assembly pathway. Glycopeptides select for diversification of the fifth position of stem pentapeptides because replacement of d -Ala by d -lactate or d -Ser at this position prevents binding of the drugs to peptidoglycan precursors. The substitution is generally well tolerated by the classical d,d -transpeptidases belonging to the penicillin-binding protein family, except by low-affinity enzymes. Total elimination of the fifth residue by a d,d -carboxypeptidase requires a novel cross-linking enzyme able to process the resulting tetrapeptide stems. This enzyme, an l,d -transpeptidase, confers cross-resistance to ,-lactams and glycopeptides. Diversification of the side chain of the precursors, presumably in response to the selective pressure of peptidoglycan endopeptidases, is controlled by aminoacyl transferases of the Fem family that redirect specific aminoacyl-tRNAs from translation to peptidoglycan synthesis. Diversification of the side chains has been accompanied by a parallel divergent evolution of the substrate specificity of the l,d -transpeptidases, in contrast to the d,d -transpeptidases, which display an unexpected broad specificity. This review focuses on the role of antibiotics in selecting or counter-selecting diversification of the structure of peptidoglycan precursors and their mode of polymerization. [source] Acquisition of Spanish Gender Agreement in Two Learning Contexts: Study Abroad and At HomeFOREIGN LANGUAGE ANNALS, Issue 2 2010Christina Isabelli-García Abstract: The goal of this study is to describe the acquisition rate for gender acquisition in Spanish and to show whether individual variability and language contact may affect this rate. The participants were intermediate second language Spanish (first language English) learners in the study abroad and at-home contexts over a 4-month period. The participants received grammaticality judgment tests coded for morphological class of the modified noun as well as attributive and predicative adjectives. Data were also collected on social behavior and language contact in Spanish and English in order to explain data outcome. The findings suggest that no difference exists between the two learning contexts and that social behavior and language contact abroad have minimal influence on acquisition rate. [source] The Role of Structural Position in L2 Phonological Acquisition: Evidence from English Learners of Spanish as L2FOREIGN LANGUAGE ANNALS, Issue 2 2008Gabriela Vokic Abstract: In this pilot study, the speech of 12 adult native speakers of English with intermediate to intermediate-high proficiency in Spanish as a second language (L2) was analyzed to determine whether L2 learners rely on distributional information in the process of L2 speech learning and if so, if similar or dissimilar distributional patterns of sounds are more easily acquired. The parameter for (dis)similarity was set around the notion of structural position in combination with native language (L1) and L2 phonemic inventories. The results show that the subjects were consistently more successful in producing the phonemes with overlapping distributional patterns in L1 and L2 than phonemes whose distribution differed in L1 and L2 as well as novel L2 contrasts. [source] Explicit Input Enhancement: Effects on Target and Non-Target Aspects of Second Language AcquisitionFOREIGN LANGUAGE ANNALS, Issue 4 2006Article first published online: 31 DEC 200, Carolyn Gascoigne Many recent studies have examined the effectiveness of various types of input enhancement. The following study expands this line of inquivy to include tech nological applications of language learning by comparing the effectiveness of the com puter application of diacritics to a traditional pen-and-paper process among beginning students of French and Spanish. In addition to studying the effect of computer-mediated input enhancement on the recall of accents, this study also questions the incidental effects of input enhancement on non-target aspects of the second language acquisition (SLA) process. Results support the effectiveness of explicit and computer-mediated input enhancement. [source] Second Language Vocabulary Acquisition: A Lexical Input Processing ApproachFOREIGN LANGUAGE ANNALS, Issue 2 2004Article first published online: 31 DEC 200, Joe Barcroft PhD These principles emphasize presentation of new words as input, allocation of limited processing resources during vocabulary acquisition, distinct components of vocabulary knowledge (e.g., form, meaning, mapping), and appropriate types of instruction for different stages of development. Empirical support is included. [source] Order of genetic events is critical determinant of aberrations in chromosome count and structureGENES, CHROMOSOMES AND CANCER, Issue 4 2004Christine Fauth A sequential acquisition of genetic events is critical in tumorigenesis. A key step is the attainment of infinite proliferative potential. Acquisition of this immortalization requires the activation of telomerase in addition to other activities, including inactivation of TP53 and the retinoblastoma family of tumor-suppressor proteins. However, the importance of the order in which these genetic events occur has not been established. To address this question, we used a panel of normal mammary fibroblasts and endothelial cultures that were immortalized after transduction with the catalytic subunit of telomerase (hTERT) and a temperature-sensitive mutant of the SV40 large-tumor (tsLT) oncoprotein in different orders in early- and late-passage stocks. These lines were maintained in continuous culture for up to 90 passages, equivalent to >300 population doublings (PDs) post-explantation during 3 years of continuous propagation. We karyotyped the cultures at different passages. Cultures that received hTERT first followed by tsLT maintained a near-diploid karyotype for more than 150 PDs. However, in late-passage stocks (>200 PDs), metaphase cells were mostly aneuploid. In contrast, the reverse order of gene transduction resulted in a marked early aneuploidy and chromosomal instability, already visible after 50 PDs. These results suggest that the order of genetic mutations is a critical determinant of chromosome count and structural aberration events. © 2004 Wiley-Liss, Inc. [source] How Culture Helped Dow AgroSciences Succeed in Achieving Business Objectives of an AcquisitionGLOBAL BUSINESS AND ORGANIZATIONAL EXCELLENCE, Issue 1 2001Henry W. Head When Mycogen Seeds, a subsidiary of Dow AgroSciences (DAS), purchased Cargill Hybrid Seeds, there were good business reasons to do so. But DAS knew that achieving the promising business synergies depended upon successfully blending not just the businesses, but the culture in which the critical people would work. So they established a cross-functional integration team whose efforts both embodied a culture of respect for each individual and built as smooth a path as possible to achieve the underlying business objectives. © 2001 John Wiley & Sons, Inc. [source] Predictors of Chain Acquisition among Independent Dialysis FacilitiesHEALTH SERVICES RESEARCH, Issue 2 2010Alyssa S. Pozniak Objective. To determine the predictors of chain acquisition among independent dialysis providers. Data Sources. Retrospective facility-level data combined from CMS Cost Reports, Medical Evidence Forms, Annual Facility Surveys, and claims for 1996,2003. Study Design. Independent dialysis facilities' probability of acquisition by a dialysis chain (overall and by chain size) was estimated using a discrete time hazard rate model, controlling for financial and clinical performance, practice patterns, market factors, and other facility characteristics. Data Collection. The sample includes all U.S. freestanding dialysis facilities that report not being chain affiliated for at least 1 year between 1997 and 2003. Principal Findings. Above-average costs and better quality outcomes are significant determinants of dialysis chain acquisition. Facilities in larger markets were more likely to be acquired by a chain. Furthermore, small dialysis chains have different acquisition strategies than large chains. Conclusions. Dialysis chains appear to employ a mix of turn-around and cream-skimming strategies. Poor financial health is a predictor of chain acquisition as in other health care sectors, but the increased likelihood of chain acquisition among higher quality facilities is unique to the dialysis industry. Significant differences among predictors of acquisition by small and large chains reinforce the importance of using a richer classification for chain status. [source] Children of Helicobacter pylori -infected Dyspeptic Mothers are Predisposed to H. pylori Acquisition with Subsequent Iron Deficiency and Growth RetardationHELICOBACTER, Issue 3 2005Yao-Jong Yang Abstract Background., We tested whether Helicobacter pylori -infected dyspeptic mothers had a higher rate of H. pylori infection in their children, and whether such H. pylori -infected children were predisposed to iron deficiency or growth retardation. Materials and methods., A total of 163 children from 106 dyspeptic mothers (58 with and 48 without H. pylori infection) were enrolled to evaluate body weight, height, hemoglobin, serum ferritin, and H. pylori infection using the 13C-urea breath test. A questionnaire was used to evaluate demographic factors of each child. Results., The rate of H. pylori infection in children with H. pylori -infected dyspeptic mothers was higher than that of children with noninfected mothers (20.5% vs. 5.3%; p < .01, OR: 4.6, 95% CI: 1.5,14.2). The rate of H. pylori infection in children elevated as the number of their H. pylori -infected siblings increased (p < .01). For children below 10 years of age, H. pylori infection was closely related to low serum ferritin and body weight growth (p < .05). Conclusion., The children of H. pylori -infected dyspeptic mothers had an increased risk for such infection. The risk further increased once their siblings were infected. H. pylori infection in pre-adolescent children may determine iron deficiency and growth retardation. [source] Age at Acquisition of Helicobacter pylori Infection: Comparison of Two Areas with Contrasting Risk of Gastric CancerHELICOBACTER, Issue 3 2004M. Constanza Camargo ABSTRACT Background.,Helicobacter pylori infection is usually acquired during childhood and is a known risk factor for the development of gastric malignancies in adulthood. It has been reported that early age at first infection may determine a neoplastic outcome in adults. The purpose of this study was to determine the prevalence of Helicobacter pylori infection in children residing in areas with high (Pasto) and low risk (Tumaco) of gastric cancer in Colombia to evaluate whether differences in the age of acquisition of H. pylori infection were present in the two populations. Materials and Methods., The study sample was based on a census taken in 1999. Using the 13C-urea breath test, we compared the prevalence of H. pylori infection among children aged 1,6 years. Results., Among 345 children in Pasto, 206 (59.7%) were H. pylori -positive, compared with 188 (58.6%) among 321 children in Tumaco. The two populations share a common pattern of very early age at infection and marked increase in prevalence during the first 4 years of life. No differences in any one year were observed when comparing the two groups. Conclusions., The prevalence of infection was similarly high and increased with age in both populations. In these populations the age of acquisition of H. pylori after 1 year of age does not appear to be a primary factor responsible for the differences in the rates of gastric cancer incidence in adults. Previous findings in adults showed lower prevalence of the most virulent genotypes in Tumaco compared to Pasto, and bacterial virulence may play a key role in determining cancer outcome. [source] Age at Acquisition of Helicobacter pylori in a Pediatric Canadian First Nations PopulationHELICOBACTER, Issue 2 2002Samir K. Sinha Abstract Background. Few data exist regarding the epidem-iology of Helicobacter pylori infections in aboriginal, including the First Nations (Indian) or Inuit (Eskimo) populations of North America. We have previously found 95% of the adults in Wasagamack, a First Nations community in Northeastern Manitoba, Canada, are seropositive for H. pylori. We aimed to determine the age at acquisition of H. pylori among the children of this community, and if any association existed with stool occult blood or demographic factors. Materials and Methods. We prospectively enrolled children resident in the Wasagamack First Nation in August 1999. A demographic questionnaire was administered. Stool was collected, frozen and batch analyzed by enzyme-linked immunosorbent assay (ELISA) for H. pylori antigen and for the presence of occult blood. Questionnaire data were analyzed and correlated with the presence or absence of H. pylori. Results. 163 (47%) of the estimated 350 children aged 6 weeks to 12 years, resident in the community were enrolled. Stool was positive for H. pylori in 92 (56%). By the second year of life 67% were positive for H. pylori. The youngest to test positive was 6 weeks old. There was no correlation of a positive H. pylori status with gender, presence of pets, serum Hgb, or stool occult blood. Forty-three percent of H. pylori positive and 24% of H. pylori negative children were < 50th percentile for height (p = 0.024). Positive H. pylori status was associated with the use of indoor pail toileting (86/143) compared with outhouse toileting (6/20) (p = 0.01). Conclusions. In a community with widespread H. pylori infection, overcrowded housing and primitive toileting, H. pylori is acquired as early as 6 weeks of age, and by the second year of life 67% of children test positive for H. pylori. [source] The North American Naturalization Gap: An Institutional Approach to Citizenship Acquisition in the United States and Canada,INTERNATIONAL MIGRATION REVIEW, Issue 1 2002Irene Bloemraad Using 1990 U.S. Census 5% PUMS and 1991 Canadian Census 3% public and 20% restricted microfiles, this article demonstrates the existence of a North American naturalization gap: immigrants living in Canada are on average much more likely to be citizens than their counterparts in the United States, and they acquire citizenship much faster than those living south of the border. Current theories explaining naturalization differences , focusing on citizenship laws, group traits or the characteristics of individual migrants , fail to explain the naturalization gap. Instead, I propose an institutional approach to citizenship acquisition. States' normative stances regarding immigrant integration (interventionist or autonomous) generate integrated or disconnected institutional configurations between government, ethnic organizations and individuals. Evidence from a case study of Portuguese immigrants living in Massachusetts and Ontario suggests that in Toronto government bureaucrats and federal policy encourage citizenship through symbolic support and instrumental aid to ethnic organizations and community leaders. In contrast, Boston area grassroots groups are expected to mobilize and aid their constituents without direct state support, resulting in lower citizenship levels. [source] The response of Aeromonas hydrophila to oxidative stress induced by exposure to hydrogen peroxideJOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2000J.P.B. Landre Aeromonas hydrophila, an opportunist human pathogen of low virulence, was shown to display a high degree of sensitivity upon exposure to hydrogen peroxide. As with other species, Aer. hydrophila is able to develop the capacity to resist loss of viability induced by such oxidative stress. Development of stress resistance follows the archetypal profile where pre-exposure of a population to sub-lethal levels of H2O2 stimulates onset of tolerance to further exposure. Acquisition of tolerance critically requires nascent protein synthesis. Further analysis demonstrated population growth phase influences the degree of sensitivity of the organism. Late stationary phase cultures demonstrate a decreased sensitivity compared with younger populations. Significantly, it was also determined that stock culture age influenced the level of sensitivity of the derived experimental culture, where an increased stock culture age corresponded with enhanced resistance to H2O2. These data show that Aer. hydrophila population phenotype is influenced by the phenotype of the donor stock culture. [source] Reporting Frequency, Information Precision and Private Information AcquisitionJOURNAL OF BUSINESS FINANCE & ACCOUNTING, Issue 1-2 2010Rick Cuijpers Abstract:, This study examines whether the choice between quarterly and semiannual reporting affects the precision of investors' information and their private information acquisition activities. In the first part of this study, we show that a firm's reporting frequency has no effect on the average precision of investors' information. However, our analysis of announcement-period price variance and share turnover shows that an increase in reporting frequency does make interim and annual financial reports a more important component of investors' information set, relative to other sources of information. In particular, the results of this analysis suggest that investors of semiannual reporters hold more precise pre-announcement information than investors of quarterly reporters. In the second part of our study, we test one explanation for this finding. We argue that an increase in a firm's reporting frequency reduces investors' incentives to acquire private information between consecutive announcement dates and, consequently, should reduce information asymmetry among investors, increase share liquidity, and stimulate trading. Consistent with this reasoning, we find that quarterly reporters have lower average bid-ask spreads and higher abnormal share turnover than semiannual reporters. [source] | ||||||||||||||||||||||||||||||||||