790 research outputs found
Comments on "Observation of Long-Range, Near-Side Angular Correlations in Proton-Proton Collisions at the LHC" by the CMS collaboration(arXiv:1009.4122v1 [hep-ex])"
It is the purpose of this note to point out that the CMS observation is in
line with previous observations in particle physics at large transverse momenta
and/or high multiplicities at lower energies, which were interpreted as
possible evidence for quark-gluon plasma (QGP), and to suggest other features
of the QGP observed in A+A collisions such as radial flow and jet quenching,
which should be investigated in p-p collisions in order to provide further
evidence for QGP production
Boson Interferometry in High Energy Physics
Intensity interferometry and in particular that due to Bose Einstein
correlations (BEC) constitutes at present the only direct experimental method
for the determination of sizes and lifetimes of sources in particle and nuclear
physics. The measurement of these is essential for an understanding of the
dynamics of strong interactions which are responsible for the existence and
properties of atomic nuclei. Moreover a new state of matter, quark matter, in
which the ultimate constituents of matter move freely, is within the reach of
present accelerators or those under construction. The confirmation of the
existence of this new state is intimately linked with the determination of its
space-time properties. Furthermore BEC provides information about quantum
coherence which lies at the basis of the phenomenon of Bose-Einstein
condensation seen in many chapters of physics. Coherence and the associated
classical fields are essential ingredients in modern theories of particle
physics including the standard model. Last but not least besides this
"applicative" aspect of BEC, this effect has implications for the foundations
of quantum mechanics including the understanding of the concept of ``identical
particles". Recent theoretical developments in BEC are reviewed and their
application in high energy particle and heavy-ion reactions is analyzed. The
treated topics include: a) a comparison between the wave-function approach and
the space-time approach based on classical currents, which predicts
"surprising" particle anti-particle BEC b) the study of final state
interactions c) the use of hydrodynamics d) the relation between correlations
and multiplicity distributions.Comment: LaTeX file and 10 postscript files with figures, 149 pages
altogether. To be published in Phys. Rep. (1999
Likelihood of Using Drug Courts: Predictions Using Procedural Justice and the Theory of Planned Behavior
The current research compares two theoretical models borrowed from social psychology (theory of planned behavior and procedural justice) to predict intentions to make use of a drug court. Medicaid-eligible substance users answered a number of questions regarding their intentions to use a drug court in the future, including items from planned behavior and procedural justice scales. When procedural justice was considered alone, only trustworthiness predicted intention to use drug courts. When planned behavior was considered alone, only deliberative attitudes predicted the intention. After combining the two models, deliberative attitudes from the theory of planned behavior were the only significant predictor of likelihood to make use of a drug court. Recommendations for future study of this area center on conceptualization of procedural justice and the use of alternative samples
Recommended from our members
Patronin-mediated minus end growth is required for dendritic microtubule polarity.
Microtubule minus ends are thought to be stable in cells. Surprisingly, in Drosophila and zebrafish neurons, we observed persistent minus end growth, with runs lasting over 10 min. In Drosophila, extended minus end growth depended on Patronin, and Patronin reduction disrupted dendritic minus-end-out polarity. In fly dendrites, microtubule nucleation sites localize at dendrite branch points. Therefore, we hypothesized minus end growth might be particularly important beyond branch points. Distal dendrites have mixed polarity, and reduction of Patronin lowered the number of minus-end-out microtubules. More strikingly, extra Patronin made terminal dendrites almost completely minus-end-out, indicating low Patronin normally limits minus-end-out microtubules. To determine whether minus end growth populated new dendrites with microtubules, we analyzed dendrite development and regeneration. Minus ends extended into growing dendrites in the presence of Patronin. In sum, our data suggest that Patronin facilitates sustained microtubule minus end growth, which is critical for populating dendrites with minus-end-out microtubules
A critical appraisal of guidelines for electronic communication between patients and clinicians: the need to modernize current recommendations
Background
Patient-provider electronic communication has proliferated in recent years, yet there is a dearth of published research either leading to, or including, recommendations that improve clinical care and prevent unintended negative consequences. We critically appraise published guidelines and suggest an agenda for future work in this area.
Objective
To understand how existing guidelines align with current practice, evidence, and technology.
Methods
We performed a narrative review of provider-targeted guidelines for electronic communication between patients and providers, searching Ovid MEDLINE, Embase, and PubMed databases using relevant terms. We limited the search to articles published in English, and manually searched the citations of relevant articles. For each article, we identified and evaluated the suggested practices.
Results
Across 11 identified guidelines, the primary focus was on technical and administrative concerns, rather than on relational communication. Some of the security practices recommended by the guidelines are no longer needed because of shifts in technology. It is unclear the extent to which the recommendations that are still relevant are being followed. Moreover, there is no guideline-cited evidence of the effectiveness of the practices that have been proposed.
Conclusion
Our analysis revealed major weaknesses in current guidelines for electronic communication between patients and providers: the guidelines appear to be based on minimal evidence and offer little guidance on how best to use electronic tools to communicate effectively. Further work is needed to systematically evaluate and identify effective practices, create a framework to evaluate quality of communication, and assess the relationship between electronic communication and quality of care
Out of Plane Distortions of the Heme b of Escherichia coli Succinate Dehydrogenase
The role of the heme b in Escherichia coli succinate dehydrogenase is highly ambiguous and its role in catalysis is questionable. To examine whether heme reduction is an essential step of the catalytic mechanism, we generated a series of site-directed mutations around the heme binding pocket, creating a library of variants with a stepwise decrease in the midpoint potential of the heme from the wild-type value of +20 mV down to −80 mV. This difference in midpoint potential is enough to alter the reactivity of the heme towards succinate and thus its redox state under turnover conditions. Our results show both the steady state succinate oxidase and fumarate reductase catalytic activity of the enzyme are not a function of the redox potential of the heme. As well, lower heme potential did not cause an increase in the rate of superoxide production both in vitro and in vivo. The electron paramagnetic resonance (EPR) spectrum of the heme in the wild-type enzyme is a combination of two distinct signals. We link EPR spectra to structure, showing that one of the signals likely arises from an out-of-plane distortion of the heme, a saddled conformation, while the second signal originates from a more planar orientation of the porphyrin ring
Recommended from our members
Application of multiplexed ion mobility spectrometry towards the identification of host protein signatures of treatment effect in pulmonary tuberculosis.
RationaleThe monitoring of TB treatments in clinical practice and clinical trials relies on traditional sputum-based culture status indicators at specific time points. Accurate, predictive, blood-based protein markers would provide a simpler and more informative view of patient health and response to treatment.ObjectiveWe utilized sensitive, high throughput multiplexed ion mobility-mass spectrometry (IM-MS) to characterize the serum proteome of TB patients at the start of and at 8 weeks of rifamycin-based treatment. We sought to identify treatment specific signatures within patients as well as correlate the proteome signatures to various clinical markers of treatment efficacy.MethodsSerum samples were collected from 289 subjects enrolled in CDC TB Trials Consortium Study 29 at time of enrollment and at the end of the intensive phase (after 40 doses of TB treatment). Serum proteins were immunoaffinity-depleted of high abundant components, digested to peptides and analyzed for data acquisition utilizing a unique liquid chromatography IM-MS platform (LC-IM-MS). Linear mixed models were utilized to identify serum protein changes in the host response to antibiotic treatment as well as correlations with culture status end points.ResultsA total of 10,137 peptides corresponding to 872 proteins were identified, quantified, and used for statistical analysis across the longitudinal patient cohort. In response to TB treatment, 244 proteins were significantly altered. Pathway/network comparisons helped visualize the interconnected proteins, identifying up regulated (lipid transport, coagulation cascade, endopeptidase activity) and down regulated (acute phase) processes and pathways in addition to other cross regulated networks (inflammation, cell adhesion, extracellular matrix). Detection of possible lung injury serum proteins such as HPSE, significantly downregulated upon treatment. Analyses of microbiologic data over time identified a core set of serum proteins (TTHY, AFAM, CRP, RET4, SAA1, PGRP2) which change in response to treatment and also strongly correlate with culture status. A similar set of proteins at baseline were found to be predictive of week 6 and 8 culture status.ConclusionA comprehensive host serum protein dataset reflective of TB treatment effect is defined. A repeating set of serum proteins (TTHY, AFAM, CRP, RET4, SAA1, PGRP2, among others) were found to change significantly in response to treatment, to strongly correlate with culture status, and at baseline to be predictive of future culture conversion. If validated in cohorts with long term follow-up to capture failure and relapse of TB, these protein markers could be developed for monitoring of treatment in clinical trials and in patient care
Electrochemical evidence that pyranopterin redox chemistry controls the catalysis of YedY, a mononuclear Mo enzyme
A long-standing contradiction in the field of mononuclear Mo enzyme research is that small-molecule chemistry on active-site mimic compounds predicts ligand participation in the electron transfer reactions, but biochemical measurements only suggest metal-centered catalytic electron transfer. With the simultaneous measurement of substrate turnover and reversible electron transfer that is provided by Fourier-transformed alternating-current voltammetry, we show that Escherichia coli YedY is a mononuclear Mo enzyme that reconciles this conflict. In YedY, addition of three protons and three electrons to the well-characterized "as-isolated" Mo(V) oxidation state is needed to initiate the catalytic reduction of either dimethyl sulfoxide or trimethylamine N-oxide. Based on comparison with earlier studies and our UV-vis redox titration data, we assign the reversible one-proton and one-electron reduction process centered around +174 mV vs. standard hydrogen electrode at pH 7 to a Mo(V)-to-Mo(IV) conversion but ascribe the two-proton and two-electron transition occurring at negative potential to the organic pyranopterin ligand system. We predict that a dihydro-to-tetrahydro transition is needed to generate the catalytically active state of the enzyme. This is a previously unidentified mechanism, suggested by the structural simplicity of YedY, a protein in which Mo is the only metal site
- …