Observational study

When we talk about knowledge of the physical world, we generally refer to facts derived from systematic observation, study, and experimentation as well as the concepts and theories based on these facts. This is contrasted with belief (faith, intuition) in the spiritual or supernatural. 

Ta.utomerism. Although tautomerism is theoretically possible ia amino and hydroxy anthraquiaone dyes, none has been observed. Studies by C nmr have shown convincingly that amino and hydroxy dyes of 9,10-anthraquiaone exist as such. 

Observation studies are conducted by actually viewing the overt actions of the respondent. In the automotive industry this can either be carried out in the field or in the factories, where subcontractors can observe their customer using their materials or components. 

It is a good practice to try and predict what level of information is expected to be extracted from the data before conducting sessions relying on observation. For instance, problems posed by movement and interaction among individuals, and the inability of a video system to capture extremely detailed events, must all be considered in advance. If certain aspects of the task are videotaped, the recording process itself should be as unobtrusive as possible. The minimum requirement is that it does not get in the way. Also, some people may react negatively to being observed and recorded. For this reason, the workers should be briefed about the objectives of the observational study in advance. 

This was a claim that I and several other authors criticized in a number of journals, but unfortunately not in Nature magazine.11 Although the authors of the Orbitals Observed study protested their innocence, it became clear that their claims had been incorrect and exaggerated.12 In a section of the same paper, I discussed the notion that the 4s atomic orbital is occupied before the 3d orbitals. This has subsequently turned out to be incorrect and there is conclusive spectroscopic evidence to the contrary which seemed to have escaped the attention of several authors who have written on this issue, including myself.13... 

Low levels of vitamin E have been associated with increased incidence of coronary artery disease. Observational studies have therefore suggested that supplemental a-tocopherol might have value in the treatment of cardiovascular disease. Clinical studies demonstrated contradicting results regarding the benefits of vitamin E in the prevention of cardiovascular disease. Four... 

To compare the epidemiological, clinical, and economic impacts of the HIV epidemic in Italy prior to and after the introduction of HAART, Tramarin et al. (2004) conducted a prospective and observational study with a multi-center design. They used data collected on an AIDS cohort from 1994 and updated data from a comparable cohort in 1998. Mortality and medical costs of 251 patients were measured in 1994 and in 1998, respectively. A considerable difference was observed in mortality (33.9% in 1994 vs. 3.9% in 1998). The cost per patient per year was US 15,515 in 1994 and US 10,312 in 1998. Based on the comparison of the two cohorts between both years, the authors concluded that after the introduction of HAART, hospital-based provision shifted from an inpatient-based to an outpatient-based service, with major focus on pharmaceutical care. 

The current evidence base for the injection of epinephrine in the initial acute treatment of anaphylaxis includes clinical experience during nearly a century of use, observational studies, epidemiological studies, fatality studies, and randomized controlled trials in people at risk for anaphylaxis although not actually experiencing it at the time of the study. Moreover, the pharmacology of epinephrine has been... 

Data on antidepressant dmgs are available from a number of sources randomized, controlled clinical trials (RCTs) in both hospital and primary-care populations decision analytic models population-based naturalistic observational studies of usual... 

Specific predictive factors for outcome after surgical intervention have not been well defined in the literature. In one prospective, multicenter observational study of 95 patients, the state of consciousness was the only predictive factor retained in a logistic regression analysis." In this study, there was a 2.8-fold increased risk for poor outcome for each increase on a three-step scale (awake/drowsy, somnolent/ stuporous, and comatose), and good outcomes (modified Rankin Scale score <2) were achieved in 86%, 76%, and 47% of patients within each group, respectively. 

Observational studies have suggested possible favourable effects of estrogen replacement therapy (ERT) on the risk of coronary heart disease in postmenopausal women. Since elevated plasma cholesterol has been identified as the primary risk factor for cardiovascular disease, investigations have focused on the inverse association between plasma cholesterol concentration and soy protein consumption. The cholesterol-lowering properties of soy have been demonstrated, and a good correlation has been found in... 

Carotenoids and cardiovascular diseases — Numerous epidemiological studies aimed to study the relationship of carotenoids and cardiovascular diseases (CVDs) including coronary accident risk and stroke. It appeared then that observational studies, namely prospective and case-control studies, pointed to a protective effect of carotenoids on myocardial infarct and stroke, but also on some atherosclerosis markers such as intima media thickness (IMT) of the common carotid artery (CCA) and atheromatous plaque formation. 

Etminan, M. et al.. The role of tomato products and lycopene in the prevention of prostate cancer a meta-analysis of observational studies. Cancer Epidemiol. Biomarkers Prev., 13, 340, 2004. 

Lindsay F.E.F. and Burton F. (1984). Observational study of urine-testing in the horse and donkey stallion. Equine Vet J 15, 330-336. 

Modification of classic risk factors, such as tobacco and alcohol consumption, is important to minimize the potential for further aggravation of heart function. Data from observational studies suggest that patients with HF who smoke have a mortality rate 40% higher than those who do not consume... 

Non-steroidal anti-inflammatory agents, aspirin, and acetaminophen have been suggested for use in the prevention of different cancers, especially hereditary non-polyposis colon cancer.14 While there have been observational studies linked to a reduction of ovarian carcinoma risk, evidence is still lacking. Potential... 

The results of these studies, when considered together and with the observational studies reviewed above, suggest that any significant effect of coffee on serum cholesterol levels is likely due to something other than caffeine content. 

Observational study evidence Case report evidence (probable or definite causality rating) ... 

Observational study evidence Diazoxide Nalidixic acid... 

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