McMaster University

About: McMaster University is a education organization based out in Hamilton, Ontario, Canada. It is known for research contribution in the topics: Population & Health care. The organization has 41361 authors who have published 101269 publications receiving 4251422 citations.

From filamentary clouds to prestellar cores to the stellar IMF: Initial highlights from the Herschel Gould Belt survey

Abstract: We summarize the first results from the Gould Belt survey, obtained toward the Aquila Rift and Polaris Flare regions during the 'science demonstration phase' of Herschel. Our 70-500 micron images taken in parallel mode with the SPIRE and PACS cameras reveal a wealth of filamentary structure, as well as numerous dense cores embedded in the filaments. Between ~ 350 and 500 prestellar cores and ~ 45-60 Class 0 protostars can be identified in the Aquila field, while ~ unbound starless cores and no protostars are observed in the Polaris field. The prestellar core mass function (CMF) derived for the Aquila region bears a strong resemblance to the stellar initial mass function (IMF), already confirming the close connection between the CMF and the IMF with much better statistics than earlier studies. Comparing and contrasting our Herschel results in Aquila and Polaris, we propose an observationally-driven scenario for core formation according to which complex networks of long, thin filaments form first within molecular clouds, and then the densest filaments fragment into a number of prestellar cores via gravitational instability.

A diffusion theory model of spatially resolved, steady-state diffuse reflectance for the noninvasive determination of tissue optical properties in vivo

Abstract: A model based upon steady-state diffusion theory which describes the radial dependence of diffuse reflectance of light from tissues is developed. This model incorporates a photon dipole source in order to satisfy the tissue boundary conditions and is suitable for either refractive index matched or mismatched surfaces. The predictions of the model were compared with Monte Carlo simulations as well as experimental measurements made with tissue simulating phantoms. The model describes the reflectance data accurately to radial distances as small as 0.5 mm when compared to Monte Carlo simulations and agrees with experimental measurements to distances as small as 1 mm. A nonlinear least-squares fitting procedure has been used to determine the tissue optical properties from the radial reflectance data in both phantoms and tissues in vivo. The optical properties derived for the phantoms are within 5%-10% of those determined by other established techniques. The in vivo values are also consistent with those reported by other investigators.

A process for systematically reviewing the literature: providing the research evidence for public health nursing interventions.

Abstract: Background: Several groups have outlined methodologies for systematic literature reviews of the effectiveness of interventions. The Effective Public Health Practice Project (EPHPP) began in 1998. Its mandate is to provide research evidence to guide and support the Ontario Ministry of Health in outlining minimum requirements for public health services in the province. Also, the project is expected to disseminate the results provincially, nationally, and internationally. Most of the reviews are relevant to public health nursing practice. Aims: This article describes four issues related to the systematic literature reviews of the effectiveness of public health nursing interventions: (1) the process of systematically reviewing the literature, (2) the development of a quality assessment instrument, (3) the results of the EPHPP to date, and (4) some results of the dissemination strategies used. Methods: The eight steps of the systematic review process including question formulation, searching and retrieving the literature, establishing relevance criteria, assessing studies for relevance, assessing relevant studies for methodological quality, data extraction and synthesis, writing the report, and dissemination are outlined. Also, the development and assessment of content and construct validity and intrarater reliability of the quality assessment questionnaire used in the process are described. Results: More than 20 systematic reviews have been completed. Content validity was ascertained by the use of a number of experts to review the questionnaire during its development. Construct validity was demonstrated through comparisons with another highly rated instrument. Intrarater reliability was established using Cohen’s Kappa. Dissemination strategies used appear to be effective in that professionals report being aware of the reviews and using them in program planning/policymaking decisions. Conclusions: The EPHPP has demonstrated the ability to adapt the most current methods of systematic literature reviews of effectiveness to questions related to public health nursing. Other positive outcomes from the process include the development of a critical mass of public health researchers and practitioners who can actively participate in the process, and the work on dissemination has been successful in attracting external funds. A program of research in this area is being developed.

Thrombotic Thrombocytopenia after ChAdOx1 nCov-19 Vaccination.

Abstract: Background Several cases of unusual thrombotic events and thrombocytopenia have developed after vaccination with the recombinant adenoviral vector encoding the spike protein antigen of sev...

Auto-shaping of the pigeon's key-peck†

Abstract: Reliable acquisition of the pigeon's key-peck response resulted from repeated unconditional (response-independent) presentations of food after the response key was illuminated momentarily. Comparison groups showed that acquisition was dependent upon light-food pairings, in that order.