1,661 research outputs found
Enhanced 2-categories and limits for lax morphisms
We study limits in 2-categories whose objects are categories with extra
structure and whose morphisms are functors preserving the structure only up to
a coherent comparison map, which may or may not be required to be invertible.
This is done using the framework of 2-monads. In order to characterize the
limits which exist in this context, we need to consider also the functors which
do strictly preserve the extra structure. We show how such a 2-category of weak
morphisms which is "enhanced", by specifying which of these weak morphisms are
actually strict, can be thought of as category enriched over a particular base
cartesian closed category F. We give a complete characterization, in terms of
F-enriched category theory, of the limits which exist in such 2-categories of
categories with extra structure.Comment: 77 pages; v2 minor changes only, to appear in Advance
Lex colimits
Many kinds of categorical structure require the existence of finite limits,
of colimits of some specified type, and of "exactness" conditions between the
finite limits and the specified colimits. Some examples are the notions of
regular, or Barr-exact, or lextensive, or coherent, or adhesive category. We
introduce a general notion of exactness, of which each of the structures listed
above, and others besides, are particular instances. The notion can be
understood as a form of cocompleteness "in the lex world" -- more precisely, in
the 2-category of finitely complete categories and finite-limit preserving
functors.Comment: 38 pages; v2: final journal version, various minor changes and new
Section 5.9 dealing with filtered colimit
Influence of Role Models and Hospital Design on the Hand Hygiene of Health-Care Workers
We assessed the effect of medical staff role models and the number of health-care worker sinks on hand-hygiene compliance before and after construction of a new hospital designed for increased access to handwashing sinks. We observed health-care worker hand hygiene in four nursing units that provided similar patient care in both the old and new hospitals: medical and surgical intensive care, hematology/oncology, and solid organ transplant units. Of 721 hand-hygiene opportunities, 304 (42%) were observed in the old hospital and 417 (58%) in the new hospital. Hand-hygiene compliance was significantly better in the old hospital (161/304; 53%) compared to the new hospital (97/417; 23.3%) (p<0.001). Health-care workers in a room with a senior (e.g., higher ranking) medical staff person or peer who did not wash hands were significantly less likely to wash their own hands (odds ratio 0.2; confidence interval 0.1 to 0.5); p<0.001). Our results suggest that health-care worker hand-hygiene compliance is influenced significantly by the behavior of other health-care workers. An increased number of hand-washing sinks, as a sole measure, did not increase hand-hygiene compliance
A Synthetic Loop Replacement Peptide That Blocks Canonical NFâ κB Signaling
Aberrant canonical NFâ κB signaling is implicated in diseases from autoimmune disorders to cancer. A major therapeutic challenge is the need for selective inhibition of the canonical pathway without impacting the many nonâ canonical NFâ κB functions. Here we show that a selective peptideâ based inhibitor of canonical NFâ κB signaling, in which a hydrogen bond in the NBD peptide is synthetically replaced by a nonâ labile bond, shows an about 10â fold increased potency relative to the original inhibitor. Not only is this molecule, NBD2, a powerful tool for dissection of canonical NFâ κB signaling in disease models and healthy tissues, the success of the synthetic loop replacement suggests that the general strategy could be useful for discovering modulators of the many proteinâ protein interactions mediated by such structures.Ein Peptidâ basierter Inhibitor für die kanonische NFâ κBâ Signalisierung, in dem eine Wasserstoffbrücke im NBDâ Peptid synthetisch durch eine nichtlabile Bindung ersetzt wurde, wirkt 10â mal stärker als der Originalinhibitor. Der Erfolg des Peptidschleifenaustauschs legt nahe, dass die Strategie nützlich sein könnte, um Modulatoren für viele durch solche Strukturen vermittelte Proteinâ Proteinâ Wechselwirkungen zu finden.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135091/1/ange201607990-sup-0001-misc_information.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/135091/2/ange201607990.pd
Centralization and directional preference: an updated systematic review with synthesis of previous evidence
Background: Centralization and directional preference are common management and prognostic factors in spinal symptoms. Objective: To update the previous systematic review. Design: Systematic review to synthesis multiple aspects of centralization and directional preference. Method: Contemporary search was made of multiple databases using relevant search terms. Abstracts and titles were filtered by two authors; relevant articles were independently reviewed by two authors for content, data extraction, and quality. Results: Forty-three additional relevant articles were found. The quality of the studies, using PEDro for randomized controlled trials, was moderate or high in six out of ten RCTs; moderate or high in six out of 12 cohort studies. Prevalence of centralization was 40%, the same as the previous review. Directional preference prevalence was only 26%, much lower than the previous review; but neither clinical response was recorded in about a third of patients. Centralization and directional preference were confirmed as key positive prognostic factors, certainly in patients with low back pain, but limited evidence for patients with neck pain. There was no evidence that these might be important treatment effect modifiers. One study evaluated reliability, and found generally poor levels, despite training. Conclusions: Centralization and directional preference are worthwhile indicators of prognosis, and should be routinely examined for even in patients with chronic low back pain. But they do not occur in all patients with spinal problems, and there was no evidence that they were treatment effect modifiers
Introductory programming: a systematic literature review
As computing becomes a mainstream discipline embedded in the school curriculum and acts as an enabler for an increasing range of academic disciplines in higher education, the literature on introductory programming is growing. Although there have been several reviews that focus on specific aspects of introductory programming, there has been no broad overview of the literature exploring recent trends across the breadth of introductory programming.
This paper is the report of an ITiCSE working group that conducted a systematic review in order to gain an overview of the introductory programming literature. Partitioning the literature into papers addressing the student, teaching, the curriculum, and assessment, we explore trends, highlight advances in knowledge over the past 15 years, and indicate possible directions for future research
Factors influencing the utilization of research findings by health policy-makers in a developing country: the selection of Mali's essential medicines
BACKGROUND: Research findings are increasingly being recognized as an important input in the formation of health policy. There is concern that research findings are not being utilized by health policy-makers to the extent that they could be. The factors influencing the utilization of various types of research by health policy-makers are beginning to emerge in the literature, however there is still little known about these factors in developing countries. The object of this study was to explore these factors by examining the policy-making process for a pharmaceutical policy common in developing countries; an essential medicines list. METHODS: A study of the selection and updating of Mali's national essential medicines list was undertaken using qualitative methods. In-depth semi-structured interviews and a natural group discussion were held with national policy-makers, most specifically members of the national commission that selects and updates the country's list. The resulting text was analyzed using a phenomenological approach. A document analysis was also performed. RESULTS: Several factors emerged from the textual data that appear to be influencing the utilization of health research findings for these policy-makers. These factors include: access to information, relevance of the research, use of research perceived as a time consuming process, trust in the research, authority of those who presented their view, competency in research methods, priority of research in the policy process, and accountability. CONCLUSION: Improving the transfer of research to policy will require effort on the part of researchers, policy-makers, and third parties. This will include: collaboration between researchers and policy-makers, increased production and dissemination of relevant and useful research, and continued and improved technical support from networks and multi-national organizations. Policy-makers from developing countries will then be better equipped to make informed decisions concerning their health policy issues
Introduction to special section on “Results of the National Science Foundation Geospace Environment Modeling Inner Magnetosphere/Storms Assessment Challenge”
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95288/1/jgra18577.pd
Interactions of Kid–Kis toxin–antitoxin complexes with the parD operator-promoter region of plasmid R1 are piloted by the Kis antitoxin and tuned by the stoichiometry of Kid–Kis oligomers
The parD operon of Escherichia coli plasmid R1 encodes a toxin–antitoxin system, which is involved in plasmid stabilization. The toxin Kid inhibits cell growth by RNA degradation and its action is neutralized by the formation of a tight complex with the antitoxin Kis. A fascinating but poorly understood aspect of the kid–kis system is its autoregulation at the transcriptional level. Using macromolecular (tandem) mass spectrometry and DNA binding assays, we here demonstrate that Kis pilots the interaction of the Kid–Kis complex in the parD regulatory region and that two discrete Kis-binding regions are present on parD. The data clearly show that only when the Kis concentration equals or exceeds the Kid concentration a strong cooperative effect exists between strong DNA binding and Kid(2)–Kis(2)–Kid(2)–Kis(2) complex formation. We propose a model in which transcriptional repression of the parD operon is tuned by the relative molar ratio of the antitoxin and toxin proteins in solution. When the concentration of the toxin exceeds that of the antitoxin tight Kid(2)–Kis(2)–Kid(2) complexes are formed, which only neutralize the lethal activity of Kid. Upon increasing the Kis concentration, (Kid(2)–Kis(2))(n) complexes repress the kid–kis operon
Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector
Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente
- …