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One Measurement (one + measurement)
Selected AbstractsDay-to-Day Variation of the Urine Protein: Creatinine Ratio in Female Dogs with Stable Glomerular Proteinuria Caused by X-Linked Hereditary NephropathyJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 3 2007Mary B. Nabity Background:Interpretation of serial urine protein: creatinine (UPC) values is confounded by a lack of data regarding random biologic variation of UPC values in dogs with stable glomerular proteinuria. Hypothesis:That there is minimal day-to-day variability in the UPC of dogs with unchanging proteinuria and the number of measurements needed to reliably estimate UPC varies with the magnitude of proteinuria. Animals:Forty-eight heterozygous (carrier) female dogs with X-linked hereditary nephropathy (XLHN) causing stable proteinuria. Methods:Urine samples were obtained daily by cystocentesis for 3 consecutive days on 183 occasions (549 samples). The UPC was measured for each sample with a single dry-film chemistry auto-analyzer. Data were analyzed retrospectively by a power of the mean model because the variance of UPC values within the 3-day evaluation periods increased as the magnitude of proteinuria increased. Results:To demonstrate a significant difference (P < .05) between serial values in these proteinuric dogs, the UPC must change by at least 35% at high UPC values (near 12) and 80% at low UPC values (near 0.5). One measurement is adequate to reliably estimate the UPC when UPC < 4, but 2,5 determinations are necessary at higher UPC values. Conclusions and Clinical Importance: These guidelines for interpretation of serial UPC values in female dogs with XLHN may also be helpful for interpretation of UPC values in dogs with other glomerulopathies. [source] Plasma triglycerides and LDL cholesterol are related in a parabolic fashion in the general population and patients with Type 2 diabetes mellitus: long-term follow-up results from the Hoorn studyDIABETIC MEDICINE, Issue 9 2008M. C. G. J. Brouwers Abstract Aims Low-density lipoprotein cholesterol (LDL-C) levels are often fairly normal in Type 2 diabetes mellitus (DM). We anticipated that a parabolic relation between plasma triglycerides and LDL-C, as previously demonstrated in familial combined hyperlipidaemia (FCHL), might account for this phenomenon. Methods Our hypothesis was tested in 1343 subjects derived from the general population who were studied on two occasions 6 years apart (the Hoorn study). Three groups were constructed depending on plasma triglycerides: group A (individuals with both measurements below 1.5 mmol/l), group B (one measurement below and one above 1.5 mmol/l) and group C (both measurements above 1.5 mmol/l). Diabetes status was ascertained by an oral glucose tolerance test. Results In a mixed linear model, a significant, positive relation between triglycerides and LDL-C was observed for males in group A (,a = 0.5, P < 0.001) and group B (,b = 0.2, P < 0.001), whereas a significant negative relation was found for males in group C (,c = ,0.2, P = 0.003). The regression slopes did not differ between diabetic and non-diabetic subjects. Similar results were obtained for women, with the exception that the relation was not significantly negative in group C (,c = ,0.1, P = 0.4). Conclusion Plasma triglcyerides and LDL-C are related in a parabolic fashion, not only in FCHL, but also in the general population and Type 2 DM. These findings aid our interpretation of typical dyslipidaemia and the effects of treatment that are frequently observed in hypertriglyceridaemic states. [source] Postprandial Hypotension in Long-Term Care Elderly Patients on Enteral FeedingJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 9 2006Emily Lubart MD OBJECTIVES: To examine the prevalence and nature of postprandial hypotension (PPH) in orally fed (OF), nasogastric tube (NGT)-fed, and percutaneous endoscopic gastrostomy (PEG)-fed older people. DESIGN: Prospective comparative study. SETTING: Nursing and skilled nursing wards of three geriatrics hospitals. PARTICIPANTS: Three groups (OF, PEG, NGT) of long-term care patients (50 in each cohort) were enrolled. MEASUREMENTS: Blood pressure (BP) and heart rate measurements were obtained just before lunch and at 15-minute intervals for 90 minutes after the completion of the meal. The meals were similar in caloric content and composition. RESULTS: PPH was evidenced in 64 (43%) patients. No significant intergroup (OF, PEG, NGT) differences were present. In 68% of PPH patients, the systolic BP (SBP) drop appeared within 30 minutes, and 70% reached their systolic nadir at 60 minutes. In 31%, the SBP drop was registered on only one measurement, whereas in 25%, the drop was detected on five to six measurements. All parameters were without notable intergroup differences. CONCLUSION: In enterally fed elderly patients (NGT or PEG), the rate and pattern of PPH are similar and not significantly different from that observed in OF patients. [source] Relative influence of male and female care in determining nestling mass in a migratory songbirdJOURNAL OF AVIAN BIOLOGY, Issue 5 2010Kirk W. Stodola Biparental care is common in birds, with the allocation of effort being highly variable between the sexes. In most songbird species, the female typically provides the most care early in the breeding cycle with both parents providing care when provisioning young. Food provisioning should be directly related to offspring quality; however, the relative influence each parent has on offspring quality has rarely been assessed at the nest level. Consequently, we were interested in assessing the relative influence male and female provisioning has on one measurement of offspring quality, nestling mass, in the black-throated blue warbler Dendroica caerulescens. Over a six year period, 2003,2008, we collected information on average nestling mass per brood on day 6 of the nestling cycle and parental provisioning rates on day 7 of the nestling cycle from 182 first brood nests on three different study plots. We found that average nestling mass was directly related to male provisioning rate, while it was not related to female provisioning rate. On the other hand, estimated biomass provisioned had little influence on average nestling mass, calling into question its utility in assessing parental quality. Finally, there was some indication that parental influence on average nestling mass was dependent on the other parent's provisioning rate, suggesting that parents work in concert to influence nestling quality. [source] Application of the parametric bootstrap method to determine statistical errors in quantitative X-ray microanalysis of thin filmsJOURNAL OF MICROSCOPY, Issue 1 2007ALDO ARMIGLIATO Summary We applied the parametric bootstrap to the X-ray microanalysis of Si-Ge binary alloys, in order to assess the dependence of the Ge concentrations and the local film thickness, obtained by using previously described Monte Carlo methods, on the precision of the measured intensities. We show how it is possible by this method to determine the statistical errors associated with the quantitative analysis performed in sample regions of different composition and thickness, but by conducting only one measurement. We recommend the use of the bootstrap for a broad range of applications for quantitative microanalysis to estimate the precision of the final results and to compare the performances of different methods to each other. Finally, we exploited a test based on bootstrap confidence intervals to ascertain if, for given X-ray intensities, different values of the estimated composition in two points of the sample are indicative of an actual lack of homogeneity. [source] Power and sample size when multiple endpoints are consideredPHARMACEUTICAL STATISTICS: THE JOURNAL OF APPLIED STATISTICS IN THE PHARMACEUTICAL INDUSTRY, Issue 3 2007Stephen Senn Abstract A common approach to analysing clinical trials with multiple outcomes is to control the probability for the trial as a whole of making at least one incorrect positive finding under any configuration of true and false null hypotheses. Popular approaches are to use Bonferroni corrections or structured approaches such as, for example, closed-test procedures. As is well known, such strategies, which control the family-wise error rate, typically reduce the type I error for some or all the tests of the various null hypotheses to below the nominal level. In consequence, there is generally a loss of power for individual tests. What is less well appreciated, perhaps, is that depending on approach and circumstances, the test-wise loss of power does not necessarily lead to a family wise loss of power. In fact, it may be possible to increase the overall power of a trial by carrying out tests on multiple outcomes without increasing the probability of making at least one type I error when all null hypotheses are true. We examine two types of problems to illustrate this. Unstructured testing problems arise typically (but not exclusively) when many outcomes are being measured. We consider the case of more than two hypotheses when a Bonferroni approach is being applied while for illustration we assume compound symmetry to hold for the correlation of all variables. Using the device of a latent variable it is easy to show that power is not reduced as the number of variables tested increases, provided that the common correlation coefficient is not too high (say less than 0.75). Afterwards, we will consider structured testing problems. Here, multiplicity problems arising from the comparison of more than two treatments, as opposed to more than one measurement, are typical. We conduct a numerical study and conclude again that power is not reduced as the number of tested variables increases. Copyright © 2007 John Wiley & Sons, Ltd. [source] Robotic total station for microtopographic mapping: an example from the Northern Great PlainsARCHAEOLOGICAL PROSPECTION, Issue 2 2006Kenneth L. Kvamme Abstract Past human activities in cultural landscapes are often expressed by subtle variations in surface topography that reflect buried archaeological features. When seen from the air under low sunlight angles, resultant ,shadow marks' form a cornerstone of site detection in aerial archaeology. Past attempts to quantify and map such variations across large archaeological landscapes have resorted to aerial photogrammetry, electronic total stations, air- and ground-based lidar, and kinematic global positioning systems. The most commonly used surveying instrument is the total station, but its slow rate of data acquisition makes it poorly suited for collecting vast amounts of elevation data over large areas, although it is often used for that task. A robotic total station, examined here, is a relatively new technology that provides a rapid survey solution. It requires only a single person to operate the total station by radio linkage from a control pad affixed to a wheeled reflector rod. As the rod is rolled over the landscape it is automatically tracked, and measurements of surface topography may be acquired to subcentimetre accuracy continuously, at a rate of one measurement per second. A case study from the Double Ditch State Historic Site in the Great Plains of North Dakota, a fortified earthlodge village with culturally significant surface expressions, exemplifies this potential. The loci of prehistoric houses, borrow pits, fortification ditches, middens and defensive mounds are clearly revealed in the topographic mapping. Copyright © 2005 John Wiley & Sons, Ltd. [source] | ||||||||||