University of Guelph

About: University of Guelph is a education organization based out in Guelph, Ontario, Canada. It is known for research contribution in the topics: Population & Gene. The organization has 26542 authors who have published 50553 publications receiving 1715255 citations. The organization is also known as: U of G & Guelph University.

Getting the Goods on Social Capital1

Abstract: This article presents an overview of the origins, development, rapid diffusion, and current usage of the concept of social capital in both the academic (research-oriented) and more applied (social policy) literature. Following a short quantitative survey of the appearance of the term in both theses and journals, various meanings of social capital are examined in the light of classical and contemporary sociological theory. Three main research approaches, which are based on the operationalization of social capital or its application as a heuristic device, are critically examined. These approaches are associated with the work ofJames Coleman, Pierre Bourdieu, and Robert Putnam, but there are also some references to the work of economists. The authors contend that, while social capital has value and appeal as a new term, basic theory needs greater development. In particular, attention should be paid to acknowledging the specific perspective on social capital that underlies its usage, the scale or level of analysis employed, and the value of a qualitative use of social capital.

Elemental Geochemistry of Sedimentary Rocks at Yellowknife Bay, Gale Crater, Mars.

Abstract: Sedimentary rocks examined by the Curiosity rover at Yellowknife Bay, Mars, were derived from sources that evolved from an approximately average martian crustal composition to one influenced by alkaline basalts. No evidence of chemical weathering is preserved, indicating arid, possibly cold, paleoclimates and rapid erosion and deposition. The absence of predicted geochemical variations indicates that magnetite and phyllosilicates formed by diagenesis under low-temperature, circumneutral pH, rock-dominated aqueous conditions. Analyses of diagenetic features (including concretions, raised ridges, and fractures) at high spatial resolution indicate that they are composed of iron- and halogen-rich components, magnesium-iron-chlorine–rich components, and hydrated calcium sulfates, respectively. Composition of a cross-cutting dike-like feature is consistent with sedimentary intrusion. The geochemistry of these sedimentary rocks provides further evidence for diverse depositional and diagenetic sedimentary environments during the early history of Mars.

The prevalence of clinically significant endoscopic findings in primary care patients with uninvestigated dyspepsia: the Canadian Adult Dyspepsia Empiric Treatment - Prompt Endoscopy (CADET-PE) study.

Abstract: Summary Background: Uninvestigated dyspepsia is common in family practice. The prevalence of clinically significant upper gastrointestinal findings (CSFs) in adult uninvestigated dyspepsia patients, and their predictability based on history, is unknown. Methods: Prompt endoscopy was performed within 10 days of referral, in 1040 adult patients presenting with uninvestigated dyspepsia at 49 Canadian family practitioner centres. Subsequent management strategies during a 6-month follow-up period were determined by the individual family practitioners. Results: CSFs were identified in 58% (603/1040) of patients. Erosive oesophagitis was most common (43%; N = 451); peptic ulcer was uncommon (5.3%; N = 55). Alarm symptoms were uncommon (2.8%; N = 29). Most patients had at least three dyspepsia symptoms, more than 80% had at least six, and approximately half had eight or more. Based on the dominant symptom, 463 (45%) patients had ulcer-like, 393 (38%) had reflux-like and 184 (18%) had dysmotility-like dyspepsia. The patients' dominant symptom was not predictive of endoscopic findings. Oesophagitis was more common in those with dominant reflux-like symptoms and was the most common finding in all subgroups. The prevalence of gastroduodenal findings was similar in all symptom subgroups. Helicobacter pylori (H. pylori) infection (30%; 301/1013) was associated with gastroduodenal findings. Conclusions: Dyspepsia subclassifications, based on dominant symptom, are of limited value in predicting the presence and nature of CSFs. Oesophagitis was by far the most common diagnosis (43% of patients). CSFs were common in uninvestigated dyspepsia patients and their nature suggests patients could be initially treated effectively, without endoscopy, using empirical acid suppressive therapy.

Carbon Sources for Bacterial Denitrification

Abstract: There are many factors that affect denitrification and these have been reviewed by Delwiche and Bryan (1976), Payne (1981), and Knowles (1982). None of these authors have provided an in-depth review of the critical role of organic carbon in the denitrification process. Organic carbon availability is one of the most important factors that affects denitrifying activity in soil, yet the chemistry of soil organic matter is only partially understood and its complexity has probably inhibited studies. A readily available C substrate is often added to denitrifying systems in the laboratory to ensure an electron supply when other variables are studied.