495 research outputs found

    \u3cb\u3eBook Review:\u3c/b\u3e \u3cem\u3eThe Course Syllabus: A Learning-centred Approach\u3c/em\u3e (2nd Ed.) by Judith Grunert O’Brien, Barbara Millis, and Margaret Cohen (Jossey Bass, 2008)

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    Excerpt: The dedication in this book clearly describes the authors’ target audience – those committed to teaching students to value the processes of learning, not just the learning. Clearly aiming the book at instructors, the authors address them throughout, emphasising the personal responsibility that..

    Price risk analysis in electricity supply

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    Towards a High Energy Theory for the Higgs Phase of Gravity

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    Spontaneous Lorentz violation due to a time-dependent expectation value for a massless scalar has been suggested as a method for dynamically generating dark energy. A natural candidate for the scalar is a Goldstone boson arising from the spontaneous breaking of a U(1) symmetry. We investigate the low-energy effective action for such a Goldstone boson in a general class of models involving only scalars, proving that if the scalars have standard kinetic terms then at the {\em classical} level the effective action does not have the required features for spontaneous Lorentz violation to occur asymptotically (t→∞)(t \to \infty) in an expanding FRW universe. Then we study the large NN limit of a renormalizable field theory with a complex scalar coupled to massive fermions. In this model an effective action for the Goldstone boson with the properties required for spontaneous Lorentz violation can be generated. Although the model has shortcomings, we feel it represents progress towards finding a high energy completion for the Higgs phase of gravity.Comment: 20 pages, 5 figures;fixed typos and added reference

    Rhapso : automatic stitching of mass segments from fourier transform ion cyclotron resonance mass spectra

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    Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) provides the resolution and mass accuracy needed to analyze complex mixtures such as crude oil. When mixtures contain many different components, a competitive effect within the ICR cell takes place that hampers the detection of a potentially large fraction of the components. Recently, a new data collection technique, which consists of acquiring several spectra of small mass ranges and assembling a complete spectrum afterward, enabled the observation of a record number of peaks with greater accuracy compared to broadband methods. There is a need for statistical methods to combine and preprocess segmented acquisition data. A particular challenge of quadrupole isolation is that near the window edges there is a drop in intensity, hampering the stitching of consecutive windows. We developed an algorithm called Rhapso to stitch peak lists corresponding to multiple different m/z regions from crude oil samples. Rhapso corrects potential edge effects to enable the use of smaller windows and reduce the required overlap between windows, corrects mass shifts between windows, and generates a single peak list for the full spectrum. Relative to a stitching performed manually, Rhapso increased the data processing speed and avoided potential human errors, simplifying the subsequent chemical analysis of the sample. Relative to a broadband spectrum, the stitched output showed an over 2-fold increase in assigned peaks and reduced mass error by a factor of 2. Rhapso is expected to enable routine use of this spectral stitching method for ultracomplex samples, giving a more detailed characterization of existing samples and enabling the characterization of samples that were previously too complex to analyze

    Investigations of pure and derivatized fullerenes by mass spectrometry

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    The following thesis represents an investigation into the gas-phase behavior of fullerenes and fullerene derivatives, using mass spectrometry as an analytical method. This thesis encompasses the formation and structure elucidation of carbon-based clusters which have been formed through the ablation of fullerene derivatives, the formation of fullerenes from non-fullerene precursor material, an evaluation of the stability of solid C60, the delayed ionization of pure fullerenes, and the assessment of an alternative ionization method for the direct analysis of fullerenes and fullerene derivatives. The coalescence reactivities of C60H36, oxides of C60, and C70, metallofullerenes, fluorinated fullerenes, and three fullerene derivatives of the formula C60[C(COOEt)2]n (where n = 1,2, and 3) have been studied. Analogously, an organometallic compound of the formula [Cp5CpMn(CO)3] has been evaluated as a possible precursor for fullerene formation using laser ablation. The stability of Q under ambient conditions, in the presence of light and air, has been studied, revealing that dimerization reactions occur following oxidation. Following analysis of the structures of coalesced species, it became apparent that time-of-flight instruments of a particular design may be prone to artifact signals originating from the delayed ionization of fullerenes; a subsequent study led to the development of a new method for examining this behavior and the findings have far reaching consequences for studies using similar instrumentation. Laser desorption/ionization and matrix-assisted laser desorption/ionization are not always suitable ionization methods due to the observation of high degrees of fragmentation or reactions with the matrix. Electrospray ionization represents an obvious solution, but an investigation into the suitability of this method was required due to the lack of successful analyses in the literature. Though the topics involved and the samples used are diverse, each investigation thus represents a mass spectrometric study into the gas-phase behavior of fullerenes and their derivatives, along one of several themes

    Characterizing lignins from various sources and treatment processes after optimized sample preparation techniques and analysis via ESI-HRMS and custom mass defect software tools

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    Sample preparation of complex, natural mixtures such as lignin prior to mass spectrometry analysis, however minimal, is a critical step in ensuring accurate and interference-free results. Modern shotgun-MS techniques, where samples are directly injected into a high-resolution mass spectrometer (HRMS) with no prior separation, usually still require basic sample pretreatment such as filtration and appropriate solvents for full dissolution and compatibility with atmospheric pressure ionization interfaces. In this study, sample preparation protocols have been established for a unique sample set consisting of a wide variety of degraded lignin samples from numerous sources and treatment processes. The samples were analyzed via electrospray (ESI)-HRMS in negative and positive ionization modes. The resulting information-rich HRMS datasets were then transformed into the mass defect space with custom R scripts as well as the open-source Constellation software as an effective way to visualize changes between the samples due to the sample preparation and ionization conditions as well as a starting point for comprehensive characterization of these varied sample sets. Optimized conditions for the four investigated lignins are proposed for ESI-HRMS analysis for the first time, giving an excellent starting point for future studies seeking to better characterize and understand these complex mixtures.Peer Reviewe

    The initial singularity of ultrastiff perfect fluid spacetimes without symmetries

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    We consider the Einstein equations coupled to an ultrastiff perfect fluid and prove the existence of a family of solutions with an initial singularity whose structure is that of explicit isotropic models. This family of solutions is `generic' in the sense that it depends on as many free functions as a general solution, i.e., without imposing any symmetry assumptions, of the Einstein-Euler equations. The method we use is a that of a Fuchsian reduction.Comment: 16 pages, journal versio

    Use of top-down and bottom-up fourier transform ion cyclotron resonance mass spectrometry for mapping calmodulin sites modified by platinum anticancer drugs

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    Calmodulin (CaM) is a highly conserved, ubiquitous, calcium-binding protein; it binds to and regulates many different protein targets, thereby functioning as a calcium sensor and signal transducer. CaM contains 9 methionine (Met), 1 histidine (His), 17 aspartic acid (Asp), and 23 glutamine acid (Glu) residues, all of which can potentially react with platinum compounds; thus, one-third of the CaM sequence is a possible binding target of platinum anticancer drugs, which represents a major challenge for identification of specific platinum modification sites. Here, top-down electron capture dissociation (ECD) was used to elucidate the transition metal–platinum(II) modification sites. By using a combination of top-down and bottom-up mass spectrometric (MS) approaches, 10 specific binding sites for mononuclear complexes, cisplatin and [Pt(dien)Cl]Cl, and dinuclear complex [{cis-PtCl2(NH3)}2(ÎŒ-NH2(CH2)4NH2)] on CaM were identified. High resolution MS of cisplatin-modified CaM revealed that cisplatin mainly targets Met residues in solution at low molar ratios of cisplatin–CaM (2:1), by cross-linking Met residues. At a high molar ratio of cisplatin:CaM (8:1), up to 10 platinum(II) bind to Met, Asp, and Glu residues. [{cis-PtCl2(NH3)}2(ÎŒ-NH2(CH2)4NH2)] forms mononuclear adducts with CaM. The alkanediamine linker between the two platinum centers dissociates due to a trans-labilization effect. [Pt(dien)Cl]Cl forms {Pt(dien)}2+ adducts with CaM, and the preferential binding sites were identified as Met51, Met71, Met72, His107, Met109, Met124, Met144, Met145, Glu45 or Glu47, and Asp122 or Glu123. The binding of these complexes to CaM, particularly when binding involves loss of all four original ligands, is largely irreversible which could result in their failure to reach the target DNA or be responsible for unwanted side-effects during chemotherapy. Additionally, the cross-linking of cisplatin to CaM might lead to the loss of the biological function of CaM or CaM–Ca2+ due to limiting the flexibility of the CaM or CaM–Ca2+ complex to recognize target proteins or blocking the binding region of target proteins to CaM

    Application of tandem two-dimensional mass spectrometry for top-down deep sequencing of calmodulin

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    Two-dimensional mass spectrometry (2DMS) involves simultaneous acquisition of the fragmentation patterns of all the analytes in a mixture by correlating their precursor and fragment ions by modulating precursor ions systematically through a fragmentation zone. Tandem two-dimensional mass spectrometry (MS/2DMS) unites the ultra-high accuracy of Fourier transform ion cyclotron resonance (FT-ICR) MS/MS and the simultaneous data-independent fragmentation of 2DMS to achieve extensive inter-residue fragmentation of entire proteins. 2DMS was recently developed for top-down proteomics (TDP), and applied to the analysis of calmodulin (CaM), reporting a cleavage coverage of about ~23% using infrared multiphoton dissociation (IRMPD) as fragmentation technique. The goal of this work is to expand the utility of top-down protein analysis using MS/2DMS in order to extend the cleavage coverage in top-down proteomics further into the interior regions of the protein. In this case, using MS/2DMS, the cleavage coverage of CaM increased from ~23% to ~42%

    Speaking up in Healthcare: An Exploration of the Allied Health New Graduate Workforce

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    Introduction: All healthcare workers are responsible for patient safety and quality improvement and need to “speak up” to communicate issues. As healthcare systems strain under the impact of reduced staffing and workloads increase, allied health new graduates are feeling under pressure and unsupported. Understanding their experiences of speaking up as they transition into the workforce will identify what support they require to fulfil their patient safety and quality improvement responsibilities. Method: An exploratory study was conducted to investigate how new graduates in allied health speak up. Informed by a realist theoretical position, this study was interested in what contexts and resources support new graduates to speak up or not. Two different focus groups with allied health new graduates were used to collect data. Reflexive thematic analysis was employed to draw out key themes and sub-themes. Results: Three main themes were generated –advocacy drives speaking up, scaffolding, and transition impact. Further analysis identified context-mechanism-outcome configurations which were then developed into an initial programme theory. Conclusion: Further in-depth exploration of speaking up behaviour with allied health new graduates will inform leaders within education and workplace settings about ways to develop confident and competent professionals who can speak up for patient safety and quality improvement
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