50 research outputs found

    Demystifying progressive design build: implementation issues and lessons learned through case study analysis

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    The design–build (DB) project delivery method has been used for several decades in the US construction market. DB contracts are usually awarded on the basis of a multicriteria evaluation, with price as one of the most salient criteria. To ensure the project’s success, an owner usually has to invest enough time and effort during scoping and early design to define a program, scope, and budget, ready for procurement and price generation. However, this process can become a burden for the owner and may lengthen the project development duration. As an alternative to the traditional DB, the progressive design–build (PDB) approach permits the selection of the DB team prior to defining the project program and/ or budget. PDB has the advantage of maintaining a single point of accountability and allowing team selection based mainly on qualifications, with a limited consideration of price. Under PDB, the selected team works with the project stakeholders during the early design stage, while helping the owner balance scope and budget. However, the key to the effectiveness of PDB is its provision for the ongoing and complete involvement of the owner in the early design phase. Due to the differences between PDB and the other project delivery methods (e.g., traditional DB), project teams must carefully consider several factors to ensure its successful implementation. The research team conducted a case study of the University of Washington’s pilot PDB project to complete the West Campus Utility Plant (WCUP). This paper carefully explores and summarizes the project’s entire delivery process (e.g., planning, solicitation, design, and construction), its organizational structures, and the project performance outcomes. The lessons learned from the WCUP project will contribute to best practices for future PDB implementation

    Changing Project Delivery Strategy: An Implementation Framework

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    For organizations such as departments of transportation, other public agencies, or private companies, adopting a new approach to procure services for delivery of construction projects requires significant organizational changes; modifications to both their work processes and existing organizational structures may be needed. These adjustments, encompassing many different aspects of the organization’s interests, must occur for the change initiative to be successfully put into practice. Research at the Center for Construction Industry Studies is investigating the adoption of integrated project delivery methods within the transportation project sector to better understand the dynamics of this change. This paper will present findings from a study of Public Owner organizations that have implemented the design-build method for delivering highway projects. Using as a case study the new $1.3 billion SH 130 tolled expressway project in Central Texas, we have analyzed project documentation, held a workshop and conducted 39 interviews with individuals affiliated with owner, legal, engineering consultants, and contractors. Findings suggest that project representatives institutionalize practices and routines connected to the new approach by adapting to new challenges, rather than “overwriting” previously existing practices. Consequently, the institutionalization of innovative approaches to project delivery happens concurrently with a deinstitutionalization of the previous approaches. This concurrency produces different effects on the project environment, depending on the mediating action of some emerging practices and the perspective of the involved parties. Building upon these findings, we have developed a conceptual framework for helping Owner organizations implement a change in their project delivery strategy. In the context of this paper, an Owner’s project delivery strategy is defined as the set of project delivery methods that are adopted for delivering capital projects. We further refined this framework by making a comparative study of four transportation projects in the United States. In addition, 35 experts in the implementation of the design-build method for transportation projects participated in a Delphi study in order to validate the developed framework. Findings from these studies, including application to the construction industry and to other industries will be presented in this paper

    Androgen-Induced Cell Migration: Role of Androgen Receptor/Filamin A Association

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    Background: Androgen receptor (AR) controls male morphogenesis, gametogenesis and prostate growth as well as development of prostate cancer. These findings support a role for AR in cell migration and invasiveness. However, the molecular mechanism involved in AR-mediated cell migration still remains elusive. Methodology/Principal Findings: Mouse embryo NIH3T3 fibroblasts and highly metastatic human fibrosarcoma HT1080 cells harbor low levels of transcriptionally incompetent AR. We now report that, through extra nuclear action, AR triggers migration of both cell types upon stimulation with physiological concentrations of the androgen R1881. We analyzed the initial events leading to androgen-induced cell migration and observed that challenging NIH3T3 cells with 10 nM R1881 rapidly induces interaction of AR with filamin A (FlnA) at cytoskeleton. AR/FlnA complex recruits integrin beta 1, thus activating its dependent cascade. Silencing of AR, FlnA and integrin beta 1 shows that this ternary complex controls focal adhesion kinase (FAK), paxillin and Rac, thereby driving cell migration. FAK-null fibroblasts migrate poorly and Rac inhibition by EHT impairs motility of androgen-treated NIH3T3 cells. Interestingly, FAK and Rac activation by androgens are independent of each other. Findings in human fibrosarcoma HT1080 cells strengthen the role of Rac in androgen signaling. The Rac inhibitor significantly impairs androgen-induced migration in these cells. A mutant AR, deleted of the sequence interacting with FlnA, fails to mediate FAK activation and paxillin tyrosine phosphorylation in androgen-stimulated cells, further reinforcing the role of AR/FlnA interaction in androgen-mediated motility. Conclusions/Significance: The present report, for the first time, indicates that the extra nuclear AR/FlnA/integrin beta 1 complex is the key by which androgen activates signaling leading to cell migration. Assembly of this ternary complex may control organ development and prostate cancer metastasis

    Search for Supersymmetry with Gauge-Mediated Breaking in Diphoton Events with Missing Transverse Energy at CDF II

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    accepted to Phys. Rev. LettWe present the results of a search for supersymmetry with gauge-mediated breaking and \NONE\to\gamma\Gravitino in the γγ\gamma\gamma+missing transverse energy final state. In 2.6±\pm0.2 \invfb of ppˉp{\bar p} collisions at s\sqrt{s}==1.96 TeV recorded by the CDF II detector we observe no candidate events, consistent with a standard model background expectation of 1.4±\pm0.4 events. We set limits on the cross section at the 95% C.L. and place the world's best limit of 149\gevc on the \none mass at τχ~10\tau_{\tilde{\chi}_1^0}$We present the results of a search for supersymmetry with gauge-mediated breaking and χ˜10→γG˜ in the γγ+missing transverse energy final state. In 2.6±0.2  fb-1 of pp̅ collisions at √s=1.96  TeV recorded by the CDF II detector we observe no candidate events, consistent with a standard model background expectation of 1.4±0.4 events. We set limits on the cross section at the 95% C.L. and place the world’s best limit of 149  GeV/c2 on the χ˜10 mass at τχ˜10≪1  ns. We also exclude regions in the χ˜10 mass-lifetime plane for τχ˜10≲2  ns.Peer reviewe

    Measurements of branching fraction ratios and CP asymmetries in B+/- ->D_CP K+/- decays in hadron collisions

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    We reconstruct B+/- -> D K+/- decays in a data sample collected by the CDF II detector at the Tevatron collider corresponding to 1 fb-1 of integrated luminosity. We select decay modes where the D meson decays to either K- pi+ (flavor eigenstate) or K- K+, pi- pi+ (CP-even eigenstates), and measure the direct CP asymmetry A_CP+ = 0.39 +/- 0.17(stat) +/- 0.04(syst), and the double ratio of CP-even to flavor eigenstate branching fractions R_CP+ = 1.30 +/- 0.24(stat) +/- 0.12(syst). These measurements will improve the determination of the CKM angle gamma. They are performed here for the first time using data from hadron collisions.We reconstruct B±→DK± decays in a data sample collected by the CDF II detector at the Tevatron collider corresponding to 1  fb-1 of integrated luminosity. We select decay modes where the D meson decays to either K-π+ (flavor eigenstate) or K-K+, π-π+ (CP-even eigenstates), and measure the direct CP asymmetry ACP+=0.39±0.17(stat)±0.04(syst), and the double ratio of CP-even to flavor eigenstate branching fractions RCP+=1.30±0.24(stat)±0.12(syst). These measurements will improve the determination of the Cabibbo-Kobayashi-Maskawa angle γ. They are performed here for the first time using data from hadron collisions.Peer reviewe

    Measurement of the Lambda_b Lifetime in Lambda_b -> Lambda_c+ pi- Decays in p-pbar Collisions at sqrt(s) = 1.96 TeV

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    Submitted to Phys. Rev. LettWe report a measurement of the lifetime of the Lambda_b baryon in decays to the Lambda_C+ pi- final state in a sample corresponding to 1.1 fb^-1 collected in p-pbar collisions at sqrt(s) = 1.96 TeV by the CDF II detector at the Tevatron collider. Using a sample of about 3000 fully reconstructed Lambda_b events we measure tau(Lambda_b) = 1.401 +- 0.046 (stat) +- 0.035 (syst) ps (corresponding to c.tau(Lambda_b) = 420.1 +- 13.7 (stat) +- 10.6 (syst) um, where c is the speed of light). The ratio of this result and the world average B^0 lifetime yields tau(Lambda_b)/tau(B^0) = 0.918 +- 0.038 (stat and syst), in good agreement with recent theoretical predictions.We report a measurement of the lifetime of the Λb0 baryon in decays to the Λc+π- final state in a sample corresponding to 1.1  fb-1 collected in pp̅ collisions at √s=1.96  TeV by the CDF II detector at the Tevatron collider. Using a sample of about 3000 fully reconstructed Λb0 events we measure τ(Λb0)=1.401±0.046(stat)±0.035(syst)  ps (corresponding to cτ(Λb0)=420.1±13.7(stat)±10.6(syst)  μm, where c is the speed of light). The ratio of this result and the world average B0 lifetime yields τ(Λb0)/τ(B0)=0.918±0.038 (stat) and (syst), in good agreement with recent theoretical predictions.Peer reviewe

    Inclusive Search for Standard Model Higgs Boson Production in the WW Decay Channel using the CDF II Detector

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    We present a search for standard model (SM) Higgs boson production using ppbar collision data at sqrt(s) = 1.96 TeV, collected with the CDF II detector and corresponding to an integrated luminosity of 4.8 fb-1. We search for Higgs bosons produced in all processes with a significant production rate and decaying to two W bosons. We find no evidence for SM Higgs boson production and place upper limits at the 95% confidence level on the SM production cross section (sigma(H)) for values of the Higgs boson mass (m_H) in the range from 110 to 200 GeV. These limits are the most stringent for m_H > 130 GeV and are 1.29 above the predicted value of sigma(H) for mH = 165 GeV.We present a search for standard model (SM) Higgs boson production using pp̅ collision data at √s=1.96  TeV, collected with the CDF II detector and corresponding to an integrated luminosity of 4.8  fb-1. We search for Higgs bosons produced in all processes with a significant production rate and decaying to two W bosons. We find no evidence for SM Higgs boson production and place upper limits at the 95% confidence level on the SM production cross section (σH) for values of the Higgs boson mass (mH) in the range from 110 to 200 GeV. These limits are the most stringent for mH>130  GeV and are 1.29 above the predicted value of σH for mH=165  GeV.Peer reviewe

    Measurement of the Top Quark Mass and ppbar -> ttbar Cross Section in the All-Hadronic Mode with the CDFII Detector

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    Submitted to Phys. Rev. DWe present a measurement of the top quark mass and of the top-antitop pair production cross section using p-pbar data collected with the CDFII detector at the Tevatron Collider at the Fermi National Accelerator Laboratory and corresponding to an integrated luminosity of 2.9 fb-1. We select events with six or more jets satisfying a number of kinematical requirements imposed by means of a neural network algorithm. At least one of these jets must originate from a b quark, as identified by the reconstruction of a secondary vertex inside the jet. The mass measurement is based on a likelihood fit incorporating reconstructed mass distributions representative of signal and background, where the absolute jet energy scale (JES) is measured simultaneously with the top quark mass. The measurement yields a value of 174.8 +- 2.4(stat+JES) ^{+1.2}_{-1.0}(syst) GeV/c^2, where the uncertainty from the absolute jet energy scale is evaluated together with the statistical uncertainty. The procedure measures also the amount of signal from which we derive a cross section, sigma_{ttbar} = 7.2 +- 0.5(stat) +- 1.0 (syst) +- 0.4 (lum) pb, for the measured values of top quark mass and JES.We present a measurement of the top quark mass and of the top-antitop (tt̅ ) pair production cross section using pp̅ data collected with the CDF II detector at the Tevatron Collider at the Fermi National Accelerator Laboratory and corresponding to an integrated luminosity of 2.9  fb-1. We select events with six or more jets satisfying a number of kinematical requirements imposed by means of a neural-network algorithm. At least one of these jets must originate from a b quark, as identified by the reconstruction of a secondary vertex inside the jet. The mass measurement is based on a likelihood fit incorporating reconstructed mass distributions representative of signal and background, where the absolute jet energy scale (JES) is measured simultaneously with the top quark mass. The measurement yields a value of 174.8±2.4(stat+JES)-1.0+1.2(syst)  GeV/c2, where the uncertainty from the absolute jet energy scale is evaluated together with the statistical uncertainty. The procedure also measures the amount of signal from which we derive a cross section, σtt̅ =7.2±0.5(stat)±1.0(syst)±0.4(lum)  pb, for the measured values of top quark mass and JES.Peer reviewe

    Comparing performance of construction projects delivered through different delivery methods

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    When new delivery methods are introduced in public procurement, it is customary to analyze and compare their performance against traditional methods. Many early studies compared performance of different project delivery systems, and often developed decision support tools to help owners follow a structured path in measuring performance and, consequently, choose the most appropriate project delivery method. However, the measurement process adopted by these studies was mostly specific to the dataset to be analyzed. Only rarely, it took into account differences deriving from varying project characteristics, and, therefore was not generalizable. Building upon these studies, this study proposes a general framework for comparing performance of projects delivered through different delivery methods. A discussion of how the framework could also be adapted to every industry sector is included. This work can help owners choose a set of metrics to evaluate and compare the performance of project portfolios delivered with more than one delivery method and different industry sector.Non UBCUnreviewedFacultyOthe
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