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Optical Tweezers studies of Nucleic Acids and their Interaction with Proteins
No full textMechanics and biological function of nucleic acids are intimately coupled. The DNA double helix must be opened to allow base pairing of RNA during transcription; RNA must bend and fold in its many cellular functions. Presented in this dissertation are two investigations of mechanical deformations of nucleic acids, conducted with optical tweezers.In the introduction, the mechanical properties of DNA and RNA and their relevance to their cellular functions are introduced, to give the reader context for the results presented in the Chapters 2 and 3. This is followed by an introduction to the theory of semiflexible polymer elasticity. The optical tweezers instruments used in conducting these investigations are then presented, along with calibration procedures and a short introduction to optical trapping physics.Chapter 2 presents an investigation of the effect of downstream DNA tension on initiation by T7 RNA polymerase. A hidden Markov model is fit to force-dependent lifetimes obtained from optical tweezers experiments, allowing us to identify which steps in initiation are force-dependent and estimate rates and transition state distances. We find that 1-2 pN of tension is sufficient to turn o gene expression by causing transcription bubble collapse and destabilizing the bound state. Our force-dependence scheme and estimated transition distances provide independent supportfor the \scrunching" model of initiation.The effects of cation binding and screening on single-stranded helix formation in poly(A) RNA are presented in Chapter 3. Magnesium and calcium bind to poly(A), stabilize the helix, and change its mechanical properties. A new model of helix-coil transitions is presented and used to estimate energetics and mechanical properties.Chapter 4 presents the first fully objective algorithm for use in analyzing the noisy staircaselike data that is often produced by single-molecule fluorescence experiments. A test based on the SIC (BIC) statistic is used in conjunction with a progressive step-placement scheme to locate changepoints (steps) in noisy data. Its performance is compared to other step detection algorithms in use by biophysicists by repeating tests performed in a recent review.Experimental protocols and computer codes used in these investigations are presentedin detail in the appendices
Downstream DNA Tension Regulates the Stability of the T7 RNA Polymerase Initiation Complex
No full textAbstractGene transcription by the enzyme RNA polymerase is tightly regulated. In many cases, such as in the lac operon in Escherichia coli, this regulation is achieved through the action of protein factors on DNA. Because DNA is an elastic polymer, its response to enzymatic processing can lead to mechanical perturbations (e.g., linear stretching and supercoiling) that can affect the operation of other DNA processing complexes acting elsewhere on the same substrate molecule. Using an optical-tweezers assay, we measured the binding kinetics between single molecules of bacteriophage T7 RNA polymerase and DNA, as a function of tension. We found that increasing DNA tension under conditions that favor formation of the open complex results in destabilization of the preinitiation complex. Furthermore, with zero ribonucleotides present, when the closed complex is favored, we find reduced tension sensitivity, implying that it is predominantly the open complex that is sensitive. This result strongly supports the “scrunching” model for T7 transcription initiation, as the applied tension acts against the movement of the DNA into the scrunched state, and introduces linear DNA tension as a potential regulatory quantity for transcription initiation
The Relationships among Employee Satisfaction, Productivity, Performance and Customer Satisfaction
No full textToday, the linkage between employee satisfaction and customer satisfaction, productivity, and performance is undeniable, based on numerous studies that support the correlation. As a result, companies have a rare opportunity to gain competitive leverage and differentiation by harnessing their greatest asset: their employees. This paper investigates the factors and the effects of developing an attractive working climate and creating space for employees’ development within the organization. The human resources management and the leadership developed by the managers are critical issues in getting the desired performances. Employees, in fact, are the most critical point of differentiation for any company in today’s business environment.employee satisfaction; employees’ development; productivity; customer satisfaction.
Identifying and quantifying load-dependence in transcription initiation by T7 RNA Polymerase
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Measurement of the semileptonic + production cross section in pp collisions at 8 TeV
No full textA measurement of the cross section for top quark-antiquark ( ) pairs produced in association with a photon in proton-proton collisions at TeV is presented. The analysis uses data collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 19.7 fb. The signal is defined as the production of a pair in association with a photon having a transverse energy larger than 25 GeV and an absolute pseudorapidity smaller than 1.44. The measurement is performed in the fiducial phase space corresponding to the semileptonic decay chain of the pair, and the cross section is measured relative to the inclusive pair production cross section. The fiducial cross section for associated pair and photon production is found to be 127 ±27 (stat+syst) fb per semileptonic final state. The measured value is in agreement with the theoretical prediction.A measurement of the cross section for top quark-antiquark (tt-bar) pairs produced in association with a photon in proton-proton collisions at sqrt(s) = 8 TeV is presented. The analysis uses data collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 19.7 inverse femtobarns. The signal is defined as the production of a tt-bar pair in association with a photon having a transverse energy larger than 25 GeV and an absolute pseudorapidity smaller than 1.44. The measurement is performed in the fiducial phase space corresponding to the semileptonic decay chain of the tt-bar pair, and the cross section is measured relative to the inclusive tt-bar pair production cross section. The fiducial cross section for associated tt-bar pair and photon production is found to be 127 +/- 27 (stat + syst) fb per semileptonic final state. The measured value is in agreement with the theoretical prediction
Combination of searches for heavy resonances decaying to WW, WZ, ZZ, WH, and ZH boson pairs in proton-proton collisions at root s=8 and 13 TeV
No full textA statistical combination of searches is presented for massive resonances decaying to WW, WZ, ZZ, WH, and ZH boson pairs in proton-proton collision data collected by the CMS experiment at the LHC. The data were taken at centre-of-mass energies of 8 and 13TeV, corresponding to respective integrated luminosities of 19.7 and up to 2.7 fb(-1). The results are interpreted in the context of heavy vector triplet and singlet models that mimic properties of composite-Higgs models predicting W' and Z' bosons decaying to WZ, WW, WH, and ZH bosons. A model with a bulk graviton that decays into WW and ZZ is also considered. This is the first combined search for WW, WZ, WH, and ZH resonances and yields lower limits on masses at 95% confidence level for W' and Z' singlets at 2.3 TeV, and for a triplet at 2.4TeV. The limits on the production cross section of a narrow bulk graviton resonance with the curvature scale of the warped extra dimension (K)over-tilde = 0.5, in the mass range of 0.6 to 4.0TeV, are the most stringent published to date. (c) 2017 The Author(s). Published by Elsevier B.V
Intellectual Capital Reporting by the New Zealand Local Government Sector
No full textSweeping financial management reforms occurred in New Zealand during the late 1980s and early 1990s which radically changed the face of the New Zealand public sector. These reforms sought to significantly restructure and reorganise local government thereby improving their effectiveness and efficiency and improving their accountability to their stakeholders. The principal vehicle for the discharge of this accountability is the annual report, which must be prepared according to Generally Accepted Accounting Practice (GAAP) and commercial principles.
Organisations in the private sector are beginning to recognise the value of accounting for intellectual capital (IC) (see for example Quinn, 1992; Brooking, 1996; Sveiby, 1997; Edvinsson Malone, 1997; Bontis, Dragonetti, Jacobsen Roos, 1999; Guthrie, Petty Johanson, 2001; Bounfour, 2003). Studies on the measurement, management and reporting of IC have been undertaken internationally in Asia (Abeysekera Guthrie, 2005; Goh Lim, 2004; Ordenez de Pablos, 2002), Australia (Guthrie Petty, 2000), Europe (Bozzolan, Favotto and Ricceri, 2003; Olsson, 2001; Ordenez de Pablos, 2004), United Kingdom (Collier, 2001; Williams, 2001) and Ireland (Brennan, 2001).
Despite the significant research interest in the field of intellectual capital internationally, scant attention has been paid to intellectual capital reporting by commercial organisations in New Zealand. An extensive review of the IC literature yielded only two New Zealand based studies (Miller Whiting, 2005; Wong Gardner, 2005). Further, no studies to date have addressed intellectual capital reporting by local governments in either New Zealand or internationally. This study aims to fill this gap through the development of an intellectual capital disclosure model that could be applied to local authorities.
The research describes and explains the development of a disclosure index used to measure the extent and quality of current intellectual capital disclosure by local authorities in New Zealand. The index was developed through a consultative process with a panel of local government stakeholders which was used to establish the weightings for each item. The final index comprised 26 items divided into three categories: internal capital, external capital and human capital. The 2004/2005 annual reports of 82 New Zealand local authorities were scored for extent and quality of disclosure against the index.
The results indicate that intellectual capital reporting by local authorities is varied. Manukau City Council scored the achieved the highest overall score (76%) out of the 82 reports analysed while Whakatane District Council scored the lowest with 33%. The most reported items were joint ventures/business collaborations and management processes. The least reported items were intellectual property and licensing agreements. The most reported category of intellectual capital was internal capital, followed by external capital. The least reported category was human capital. The findings indicate a number of areas of reporting that could be improved in order to meet with stakeholder disclosure expectations. In the internal capital category, intellectual property disclosures could be improved. In the external capital category disclosure concerning ratepayer demographics and licensing agreements could be improved. In the human capital category, disclosure of most items could be improved, in particular, entrepreneurial innovativeness and vocational qualifications.
The study provided an insight into the current level and quality of intellectual capital disclosure by the NZ local government sector. The results indicated that local authorities are disclosing some aspects of intellectual capital in their annual report, however there is no consistent reporting framework, and many areas of IC disclosures are not meeting stakeholder expectations. More research is needed in the area of intellectual capital reporting in the public sector. This study provides a preliminary framework which can be used by local authorities to enhance intellectual capital disclosures in their annual reports
