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Simple Indices (simple + index)
Selected AbstractsA Simple Index to Restrain Abnormal Protrusions in Films Fabricated Using CVD under Diffusion-Limited Conditions,CHEMICAL VAPOR DEPOSITION, Issue 4 2004Y. Kajikawa Abstract Cauliflower-like protrusions formed in CVD processes under diffusion-limited conditions have been studied both experimentally and theoretically. Both approaches indicate that the difference in diffusion fluxes to the film and to the protrusions controls the growth of such protrusions. However, direct comparisons of these two approaches have never been done, probably due to the complexity of the theoretical models. To simplify model protrusion growth, we developed a one-dimensional (1D) analytical model by hypothesizing the diffusion of growth species in the boundary layer above a growing film. Based on this model, we propose a non-dimensional quantity, ksf/D, as an index of protrusion growth (D is the diffusion coefficient of the growth species, ks is the surface reaction-rate coefficient, and f is film thickness). This index represents more directly the protrusion growth than does the previously proposed index, the Damköhler number, Da,=,ks,/D, where , is boundary layer thickness. To obtain smooth, protrusion-free films, D/ks should be kept larger than the desired film thickness. By controlling the process conditions to satisfy this index, we successfully fabricated protrusion-free films with SiC deposition from dichlorodimethylsilane (DDS). [source] Submerged macrophytes as indicators of the ecological quality of lakesFRESHWATER BIOLOGY, Issue 4 2010MARTIN SØNDERGAARD Summary 1. We analysed submerged macrophyte communities from 300 Danish lakes to determine the efficacy of different species, maximum colonisation depth (Cmax) of plants as well as coverage and plant volume inhabited (PVI) as indicators of eutrophication. 2. Most species occurred at a wide range of phosphorus and chlorophyll a (Chla) concentrations, but some species of isoetids (Lobelia, Isoëtes) and Potamogeton (Potamogeton gramineus, Potamogeton alpinus and Potamogeton filiformis) were mainly found at low nutrient concentrations and hence may be considered as indicators of nutrient poor conditions. However, species typically found in nutrient-rich conditions, such as Elodea canadensis and Potamogeton pectinatus, were also found at total phosphorus (TP) <0.02 mg P L,1 and Chla <5 ,g L,1 and therefore cannot be considered as reliable indicators of eutrophic conditions. 3. Submerged macrophyte coverage, PVI and the Cmax were negatively correlated with TP and Chla. However, variability among lakes was high and no clear thresholds were observed. At TP between 0.03 and 0.07 mg P L,1 plant coverage in shallow lakes ranged from nearly 0 to 100%, whilst at concentrations between 0.10 and 0.20 mg P L,1 only 29% of the lakes had coverage >10%. Cmax was found to be a useful indicator only in deep lakes with unvegetated areas in the deeper part, whereas the use of coverage was restricted to shallow lakes or shallow areas of deep lakes. 4. Overall, submerged macrophytes responded clearly to eutrophication, but the metrics investigated here showed no well-defined thresholds. We developed a simple index based on species richness, presence of indicator species, coverage and Cmax, which might be used to track major changes in macrophyte communities and for lake classification. [source] A simple noninvasive index can predict both significant fibrosis and cirrhosis in patients with chronic hepatitis CHEPATOLOGY, Issue 2 2003Chun-Tao Wai Information on the stage of liver fibrosis is essential in managing chronic hepatitis C (CHC) patients. However, most models for predicting liver fibrosis are complicated and separate formulas are needed to predict significant fibrosis and cirrhosis. The aim of our study was to construct one simple model consisting of routine laboratory data to predict both significant fibrosis and cirrhosis among patients with CHC. Consecutive treatment-naive CHC patients who underwent liver biopsy over a 25-month period were divided into 2 sequential cohorts: training set (n = 192) and validation set (n = 78). The best model for predicting both significant fibrosis (Ishak score , 3) and cirrhosis in the training set included platelets, aspartate aminotransferase (AST), and alkaline phosphatase with an area under ROC curves (AUC) of 0.82 and 0.92, respectively. A novel index, AST to platelet ratio index (APRI), was developed to amplify the opposing effects of liver fibrosis on AST and platelet count. The AUC of APRI for predicting significant fibrosis and cirrhosis were 0.80 and 0.89, respectively, in the training set. Using optimized cut-off values, significant fibrosis could be predicted accurately in 51% and cirrhosis in 81% of patients. The AUC of APRI for predicting significant fibrosis and cirrhosis in the validation set were 0.88 and 0.94, respectively. In conclusion, our study showed that a simple index using readily available laboratory results can identify CHC patients with significant fibrosis and cirrhosis with a high degree of accuracy. Application of this index may decrease the need for staging liver biopsy specimens among CHC patients. [source] Sex Differences in the Effect of Heart Rate on Mortality in the ElderlyJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 9 2003Gila Perk MD Objectives:, To examine the association between heart rate and mortality risk in the elderly. Design:, Longitudinal cohort. Setting:, Outpatient. Participants: Four hundred twenty-two people, aged 70 upon entry, were surveyed and followed for 6 years. Measurements: Pulse rate was measured manually, while sitting and standing, and heart rate was measured from electrocardiogram recordings. The population was divided into quartiles of heart rate, with the top quartile comprising those with heart rate greater than 77 beats per minute (bpm) and the bottom quartile those with heart rate less than 60 bpm. Results: After controlling for possible confounders, there was a clear correlation (r) between heart rate and all-cause mortality in elderly women (r=0.25, P=.0003). The correlation in women was observed using the three different methods for measuring heart rate. Heart rate was associated with all-cause and cardiovascular mortality. There was no relationship between heart rate and level of exercise or smoking status. In multiple regression analysis, the increased risk of death in the women was independent of previous cardiovascular or cerebrovascular disease, hypertension, anemia, congestive heart failure, smoking, and level of exercise or activities of daily living (relative odds ratio (ROR)=3.37, 95% confidence interval (CI)=0.96,11.8). When women using beta-blockers were excluded, this relationship became even stronger (ROR=8.5, 95% CI=1.19,60.1). Conclusion: Elevated heart rate is related to increased mortality in elderly women, thus representing a simple index of general health status in this population. Elevated heart rate did not predict mortality in elderly men. [source] ATTRITION EVALUATION FOR SELECTED AGGLOMERATED FOOD POWDERS: THE EFFECT OF AGGLOMERATE SIZE AND WATER ACTIVITYJOURNAL OF FOOD PROCESS ENGINEERING, Issue 1 2001HONG YAN ABSTRACT Investigation of the attrition of agglomerates is very important for assessing the agglomerate strength, compaction characteristics, and quality control. A one-term exponential attrition index model and the Hausner ratio were used to study the effects of agglomerate size and water activity on the attrition kinetics of some selected agglomerated food powders. It was found that the agglomerate size and water activity played significant roles in affecting the attrition: the larger the agglomerate size and the higher the water activity, the higher the attrition index under the same tap number. The Hausner ratio was well correlated with the attrition index at high tap numbers and might be used as a simple index to evaluate attrition severity for agglomerates. Knowing the effects of agglomerate size and water activity is very useful to minimize the attrition phenomenon during the handling and processing of agglomerated powders. [source] A simple morphological predictor of bite force in rodentsJOURNAL OF ZOOLOGY, Issue 4 2008P. W. Freeman Abstract Bite force was quantified for 13 species of North American rodents using a piezo-resistive sensor. Most of the species measured (11) formed a tight relationship between body mass and bite force (log 10(bite force)=0.43(log 10(body mass))+0.416; R2>0.98). This high correlation exists despite the ecological (omnivores, grazers and more carnivorous) and taxonomic (Cricetidae, Heteromyidae, Sciuridae and Zapodidae) diversity of species. Two additional species, Geomys bursarius (Geomyidae) and a Sciurus niger (Sciuridae), bit much harder for their size. We found a simple index of strength based on two measurements of the incisor at the level of the alveolus (Zi=((anterior-posterior length)2× (medial-lateral width))/6) that is highly predictive of bite force in these rodents (R2>0.96). Zi may be useful for prediction of bite force (log10 (Bite Force)=0.566log10 (Zi)+1.432) when direct measurements are not available. [source] Defining and measuring braiding intensityEARTH SURFACE PROCESSES AND LANDFORMS, Issue 14 2008Roey Egozi Abstract Geomorphological studies of braided rivers still lack a consistent measurement of the complexity of the braided pattern. Several simple indices have been proposed and two (channel count and total sinuosity) are the most commonly applied. For none of these indices has there been an assessment of the sampling requirements and there has been no systematic study of the equivalence of the indices to each other and their sensitivity to river stage. Resolution of these issues is essential for progress in studies of braided morphology and dynamics at the scale of the channel network. A series of experiments was run using small-scale physical models of braided rivers in a 3 m , 20 m flume. Sampling criteria for braid indices and their comparability were assessed using constant-discharge experiments. Sample hydrographs were run to assess the effect of flow variability. Reach lengths of at least 10 times the average wetted width are needed to measure braid indices with precision of the order of 20% of the mean. Inherent variability in channel pattern makes it difficult to achieve greater precision. Channel count indices need a minimum of 10 cross-sections spaced no further apart than the average wetted width of the river. Several of the braid indices, including total sinuosity, give very similar numerical values but they differ substantially from channel-count index values. Consequently, functional relationships between channel pattern and, for example, discharge, are sensitive to the choice of braid index. Braid indices are sensitive to river stage and the highest values typically occur below peak flows of a diurnal (melt-water) hydrograph in pro-glacial rivers. There is no general relationship with stage that would allow data from rivers at different relative stage to be compared. At present, channel count indices give the best combination of rapid measurement, precision, and range of sources from which measurements can be reliably made. They can also be related directly to bar theory for braided pattern development. Copyright © 2008 John Wiley & Sons, Ltd. [source] Functional biotic homogenization of bird communities in disturbed landscapesGLOBAL ECOLOGY, Issue 2 2008Vincent Devictor ABSTRACT Aim, Worldwide, functional homogenization is now considered to be one of the most prominent forms of biotic impoverishment induced by current global changes. Yet this process has hardly been quantified on a large scale through simple indices, and the connection between landscape disturbance and functional homogenization has hardly been established. Here we test whether changes in land use and landscape fragmentation are associated with functional homogenization of bird communities at a national scale. Location, France. Methods, We estimated functional homogenization of a community as the average specialization of the species present in that community. We studied the spatial variation of this community specialization index (CSI) using 1028 replicates from the French Breeding Bird Survey along spatial gradients of landscape fragmentation and recent landscape disturbance, measured independently, and accounting for spatial autocorrelation. Results, The CSI was very sensitive to both measures of environmental degradation: on average, 23% of the difference in the CSI values between two sample sites was attributed to the difference in fragmentation and the disturbance between sites. This negative correlation between CSI and sources of landscape degradation was consistent over various habitats and biogeographical zones. Main conclusions, We demonstrate that the functional homogenization of bird communities is strongly positively correlated to landscape disturbance and fragmentation. We suggest that the CSI is particularly effective for measuring functional homogenization on both local and global scales for any sort of organism and with abundance or presence,absence data. [source] Assessing health-related quality of life in patients with inflammatory bowel disease in Zhejiang, ChinaJOURNAL OF CLINICAL NURSING, Issue 1-2 2010Yunxian Zhou Aims., The aim of this study was to assess health-related quality of life in patients with inflammatory bowel disease in Zhejiang, Mainland China. Background., The incidence of inflammatory bowel disease in China is believed to be low but has been increasing in the past decade. The quality of life of Chinese patients with inflammatory bowel disease is unknown. Design., A cross-sectional study. Methods., The study was conducted in 92 patients with inflammatory bowel disease in Zhejiang, China, 52 with ulcerative colitis and 40 with Crohn's disease. Health-related quality of life was measured by the Chinese version of the Inflammatory Bowel Disease Questionnaire and Short Form-36, respectively. Disease activity was assessed by the Walmsley and Harvey,Bradshaw simple indices for ulcerative colitis and Crohn's disease, respectively. Demographic and clinical variables were also recorded. Short Form-36 data from the study sample were compared with a reference population of 1688 Chinese people residing in Hangzhou, Zhejiang, China. Results., No significant health-related quality of life differences were found between patients with ulcerative colitis and Crohn's disease (p > 0·05). Pooled data showed that inflammatory bowel disease patients with active disease had significantly lower scores for all eight dimensions of Short Form-36 compared to those in remission (p < 0·01); those with active disease scored significantly lower than population norms in all dimensions of Short Form-36 except mental health (p < 0·05); whereas those in remission scored significantly lower than population norms in role physical (p < 0·01) and general health dimensions (p < 0·05). The regression analyses identified only disease activity index and employment status to explain variations in health-related quality of life (p < 0·01). Conclusions., Inflammatory bowel disease similarly impairs health-related quality of life in patients with both ulcerative colitis and Crohn's disease. Relevance to clinical practice., The results suggest that any interventions that produce a stable clinical remission, whether medical or surgical, allowing patients to return to their usual work position can decrease the disease impact on their daily lives. [source] Stop test or pressure-flow study?NEUROUROLOGY AND URODYNAMICS, Issue 3 2004Measuring detrusor contractility in older females Abstract Aims Impaired detrusor contractility is common in older adults. One aspect, detrusor contraction strength during voiding, can be measured by the isovolumetric detrusor pressure attained if flow is interrupted mechanically (a stop test). Because interruption is awkward in practice, however, simple indices or nomograms based on measurements made during uninterrupted voiding are an appealing alternative. We investigated whether such methods, originally developed for males, might be applicable in female subjects, and attempted to identify a single best method. Methods We compared stop-test isovolumetric pressures with estimates based on pressure-flow studies in a group of elderly women suffering from urge incontinence. Measurements were made pre- and post-treatment with placebo or oxybutynin, allowing investigation of test,retest reliability and responsiveness to small changes of contractility. Results Existing methods of estimating detrusor contraction strength from pressure-flow studies, including the Schäfer contractility nomogram and the projected isovolumetric pressure PIP, greatly overestimate the isovolumetric pressure in these female patients. A simple modification provides a more reliable estimate, PIP1, equal to pdet.Qmax,+,Qmax (with pressure in cmH2O and Qmax in ml/sec). Typically PIP1 ranges from 30 to 75 cmH2O in this population of elderly urge-incontinent women. PIP1, however, is less responsive to a small change in contraction strength than the isovolumetric pressure measured by mechanical interruption. Conclusions The parameter PIP1 is simple to calculate from a standard pressure-flow study and may be useful for clinical assessment of detrusor contraction strength in older females. For research, however, a mechanical stop test still remains the most reliable and responsive method. The Schäfer contractility nomogram and related parameters such as DECO and BCI are not suitable for use in older women. Neurourol. Urodynam. 23:184,189, 2004. © 2004 Wiley-Liss, Inc. [source] Habitat indices for rivers: derivation and applicationsAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue S1 2010Ian P. Vaughan Abstract 1.River Habitat Survey (RHS) is the standard riverine hydromorphology survey in the UK and modified versions have been adopted in several other European Countries. It aims to broadly characterize physical features over 500,m reaches, but in so doing records more than 100 variables, often making interpretation and data analysis challenging. In such instances, synoptic treatment of the data, creating simple indices such as Habitat Modification and Habitat Quality Assessment scores, can prove beneficial. 2.The derivation of seven new indices is described, summarizing nearly half of the variables used by RHS and providing a quantitative overall summary of river reaches. 3.Derived using an objective analysis of the RHS database (cf expert judgement), one index describes bedrock/boulder channels, two indices describe bank and riparian vegetation and a further two describe aspects of sediment transport and deposition. Two distinct types of modification,,,bank reinforcement and channel re-sectioning,,,are also quantified. 4.Rigorous testing indicates that the indices are reliable across the complete range of conditions and countries in the UK. 5.The new indices are readily interpreted and while providing a simple overview of a river reach, they are objective and quantitative, lending themselves to a range of management and research applications. They have already been used successfully in quantifying riverine bird habitats and this, along with other applications, is discussed. Copyright © 2009 John Wiley & Sons, Ltd. [source] Implications of spatial variability of fish assemblages for monitoring of Australia's tropical estuariesAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 3 2010Marcus Sheaves Abstract 1. Although often seen as ideal targets for monitoring environmental change because of their high public profile, fish assemblages rarely appear as indicators in monitoring and reporting. 2. Published data were evaluated to develop a simple approach to quantifying the temporal consistency in assemblage structure suitable for routine monitoring and assessment. Data were examined as catch per unit effort (CPUE) and probability of encounter (PoE), and compared using three approaches with the potential to produce simple indices quantifying the patterns of similarity within an estuary over time: species richness, Bray-Curtis Similarities and a new approach, DeltaPoE. Indices derived from published data were then tested against a time series of data from two estuarine lakes with a history of fish kills. 3. Multidimensional scaling based on PoE emphasizes the temporal consistency of fish assemblages within estuaries at least as well as one based on mean CPUE while providing operational advantages. Similarities based on PoE were more sensitive to change from ,natural' assemblage structure than the simpler indices and showed comparable results with Similarities from (log) CPUE data. The one drawback to Similarities is that their complex statistical formulation often makes them less effective vehicles for reporting and communication. Where this is the case the conceptual simplicity of DeltaPoE and its performance relative to Similarities suggests it is a good candidate from which to develop monitoring indices suitable for routine reporting. 4. The performance of each of the indices were considered against the known fish kills. Species richness tracked the observed changes, an expected outcome in this case because a major impact directly removed species. Both indices based on Similarities also tracked the changes faithfully. Of the two, Similarities based on PoE seemed to react more strongly to assemblage changes. Copyright © 2010 John Wiley & Sons, Ltd. [source] | |||||||||||||