University of Toronto

About: University of Toronto is a education organization based out in Toronto, Ontario, Canada. It is known for research contribution in the topics: Population & Health care. The organization has 126067 authors who have published 294940 publications receiving 13536856 citations. The organization is also known as: UToronto & U of T.

Prediction of psychosis in youth at high clinical risk: a multisite longitudinal study in North America.

Abstract: Context Early detection and prospective evaluation of individuals who will develop schizophrenia or other psychotic disorders are critical to efforts to isolate mechanisms underlying psychosis onset and to the testing of preventive interventions, but existing risk prediction approaches have achieved only modest predictive accuracy. Objectives To determine the risk of conversion to psychosis and to evaluate a set of prediction algorithms maximizing positive predictive power in a clinical high-risk sample. Design, Setting, and Participants Longitudinal study with a 2½-year follow-up of 291 prospectively identified treatment-seeking patients meeting Structured Interview for Prodromal Syndromes criteria. The patients were recruited and underwent evaluation across 8 clinical research centers as part of the North American Prodrome Longitudinal Study. Main Outcome Measure Time to conversion to a fully psychotic form of mental illness. Results The risk of conversion to psychosis was 35%, with a decelerating rate of transition during the 2½-year follow-up. Five features assessed at baseline contributed uniquely to the prediction of psychosis: a genetic risk for schizophrenia with recent deterioration in functioning, higher levels of unusual thought content, higher levels of suspicion/paranoia, greater social impairment, and a history of substance abuse. Prediction algorithms combining 2 or 3 of these variables resulted in dramatic increases in positive predictive power (ie, 68%-80%) compared with the prodromal criteria alone. Conclusions These findings demonstrate that prospective ascertainment of individuals at risk for psychosis is feasible, with a level of predictive accuracy comparable to that in other areas of preventive medicine. They provide a benchmark for the rate and shape of the psychosis risk function against which standardized preventive intervention programs can be compared.

What would it take for renewably powered electrosynthesis to displace petrochemical processes

Abstract: Electrocatalytic transformation of carbon dioxide (CO2) and water into chemical feedstocks offers the potential to reduce carbon emissions by shifting the chemical industry away from fossil fuel dependence. We provide a technoeconomic and carbon emission analysis of possible products, offering targets that would need to be met for economically compelling industrial implementation to be achieved. We also provide a comparison of the projected costs and CO2 emissions across electrocatalytic, biocatalytic, and fossil fuel-derived production of chemical feedstocks. We find that for electrosynthesis to become competitive with fossil fuel-derived feedstocks, electrical-to-chemical conversion efficiencies need to reach at least 60%, and renewable electricity prices need to fall below 4 cents per kilowatt-hour. We discuss the possibility of combining electro- and biocatalytic processes, using sequential upgrading of CO2 as a representative case. We describe the technical challenges and economic barriers to marketable electrosynthesized chemicals.

Guidelines 2000 for Colon and Rectal Cancer Surgery

Abstract: Background Oncologic resection techniques affect outcome for colon cancer and rectal cancer, but standardized guidelines have not been adopted. The National Cancer Institute sponsored a panel of experts to systematically review current literature and to draft guidelines that provide uniform definitions, principles, and practices. Methods Methods were similar to those described by the American Society of Clinical Oncology in developing practice guidelines. Experts representing oncology and surgery met to review current literature on oncologic resection techniques for level of evidence (I-V, where I is the best evidence and V is the least compelling) and grade of recommendation (A-D, where A is based on the best evidence and D is based on the weakest evidence). Initial guidelines were drafted, reviewed, and accepted by consensus. Results For the following seven factors, the level of evidence was II, III, or IV, and the findings were generally consistent (grade B): anatomic definition of colon versus rectum, tumor-node-metastasis staging, radial margins, adjuvant R0 stage, inadvertent rectal perforation, distal and proximal rectal margins, and en bloc resection of adherent tumors. For another seven factors, the level of evidence was II, III, or IV, but findings were inconsistent (grade C): laparoscopic colectomy; colon lymphadenectomy; level of proximal vessel ligation, mesorectal excision, and extended lateral pelvic lymph node dissection (all three for rectal cancer); no-touch technique; and bowel washout. For the other four factors, there was little or no systematic empirical evidence (grade D): abdominal exploration, oophorectomy, extent of colon resection, and total length of rectum resected. Conclusions The panel reports surgical guidelines and definitions based on the best available evidence. The availability of more standardized information in the future should allow for more grade A recommendations.

Orbital migration of the planetary companion of 51 Pegasi to its present location

Abstract: THE recent discovery1 and confirmation2 of a possible planetary companion orbiting the solar-type star 51 Pegasi represent a breakthrough in the search for extrasolar planetary systems. Analysis of systematic variations in the velocity of the star indicate that the mass of the companion is approximately that of Jupiter, and that it is travelling in a nearly circular orbit at a distance from the star of 0.05 AU (about seven stellar radii). Here we show that, if the companion is indeed a gas-giant planet, it is extremely unlikely to have formed at its present location. We suggest instead that the planet probably formed by gradual accretion of solids and capture of gas at a much larger distance from the star (∼5 AU), and that it subsequently migrated inwards through interactions with the remnants of the circumstellar disk. The planet's migration may have stopped in its present orbit as a result of tidal interactions with the star, or through truncation of the inner circumstellar disk by the stellar magnetosphere.