Second Set Of Criteria Research Articles

Multicriteria parameter estimation for models of stream chemical composition

The inability to develop an accurate and precise parameter estimation method for catchment hydrochemical models has been a persistent problem. We investigate the use of multicriteria calibration techniques and the selection of the criteria as a first step in solving this problem. We applied a multicriteria search algorithm to the Alpine Hydrochemical Model (AHM) of the Emerald Lake watershed, Sequoia National Park, California. A total of 21 chemical and hydrologic criteria were available for determining model performance. Four subsets of these criteria were selected for the multicriteria analysis using three different methods. The first set used the four least correlated observations of stream chemical composition. A second set of criteria was determined by using the four species with the least correlated root mean square error criteria values (ρ < 0.05 for each pair). Finally, two sets were chosen using the results of a multicriteria sensitivity analysis. The most accurate and precise results were observed using criteria selected using results from a sensitivity analysis, with the correlation analyses being a poor method for selecting criteria. This set of criteria emphasizes attributes of the model structure, the observations, and our understanding of the processes influencing watershed hydrology and water quality. Also, our results gave improved estimates of several hydrologic and biogeochemical processes in addition to identifying a flaw in the current representation of mineral weathering within the AHM, as applied to the Emerald Lake watershed.

Staging of preclinical type 1 diabetes in siblings of affected children. Childhood Diabetes in Finland Study Group.

To assess whether it is clinically relevant to classify siblings of children with recent-onset type 1 diabetes mellitus (T1DM) into various stages of preclinical diabetes, and to compare the risk of developing clinical disease and the time to diagnosis between these stages. From a total of 801 families taking part in the Childhood Diabetes in Finland Study, 758 initially unaffected siblings were graded into four stages of preclinical T1DM based on the number of disease-associated autoantibodies detectable close to the time of diagnosis in the index case: no (no antibodies), early (one antibody specificity), advanced (two antibodies), and late prediabetes (more than three antibodies). Another classification system, used with 712 siblings, was based on a combination of the number of antibodies and the first-phase insulin response (FPIR) to intravenous glucose: no (no antibodies), early (one antibody specificity, normal FPIR), advanced (two or more antibodies, normal FPIR), and late prediabetes (one or more antibodies, reduced FPIR). Six out of 661 siblings who initially presented no signs of prediabetes (0.9%; 95% confidence interval [CI], 0.3%-2.0%) progressed to clinical T1DM. Based on the first set of criteria, 3 out of 49 individuals (6.1%; CI, 1.3%-16. 9%; odds ratio [OR], 7.1; CI, 1.7-29.4) from the early prediabetes category, 3 out of 13 with advanced prediabetes (23.1%; CI, 5.0%-53. 8%; OR, 32.8; CI, 7.2-150), and 23 out of 35 with late prediabetes (65.7%; CI, 47.8%-80.9%; OR, 209; CI, 72.2-607) presented with clinical signs of T1DM. According to the second set of criteria 1 out of 15 siblings with early prediabetes (6.7%; CI, 0.2%-32.0%; OR, 7.8; CI, 0.9-69.1), 6 out of 23 with advanced prediabetes (26.1%; CI, 10.2%-48.4%; OR, 38.5; CI, 11.3-132), and 12 out of 13 with late prediabetes (92.3%; CI, 64.0%-99.8%; OR, 1310; CI, 146-11 737) presented with clinical signs of T1DM. The time to diagnosis was significantly shorter in those with late prediabetes initially than in those with no signs of prediabetes. Our observations indicate that it is possible to grade siblings of children with newly diagnosed T1DM into categories with significant differences in the subsequent risk of clinical T1DM and time to diagnosis. Such a classification will become clinically relevant as soon as effective measures are available for preventing or delaying the manifestation of overt T1DM.autoantibodies, classification, prospective, first-phase insulin response.

PROCESS TO IDENTIFY AND EVALUATE RESTORATION OPTIONS

ABSTRACT The restoration planning process has yielded a number of possible alternatives for restoring resources and services injured by the Exxon Valdez oil spill. They were developed by resource managers, scientists, and the public, taking into consideration the results of damage assessment and restoration studies and information from the scientific literature. The alternatives thus far identified include no action natural recovery, management of human uses, manipulation of resources, habitat protection and acquisition, acquisition of equivalent resources, and combinations of the above. Each alternative consists of a different mix of resource- or service-specific restoration options. To decide whether it was appropriate to spend restoration funds on a particular resource or service, first criteria had to be developed that evaluated available evidence for consequential injury and the adequacy and rate of natural recovery. Then, recognizing the range of effective restoration options, a second set of criteria was applied to determine which restoration options were the most beneficial. These criteria included technical feasibility, potential to improve the rate or degree of recovery, the relationship of expected costs to benefits, cost effectiveness, and the potential to restore the ecosystem as a whole. The restoration options considered to be most beneficial will be grouped together in several or more of the above alternatives and presented in a draft restoration plan. They will be further evaluated in a companion draft environmental impact statement.

Perspective: Defining lead as the premiere environmental health issue for children in America: Criteria and their quantitative application

The principal environmental health issue for American children is pervasive lead poisoning from the many decades of lead contamination. Available scientific evidence cementing lead's premiere ranking is voluminous, multifaceted, and compelling. This evidence, however, requires organization into a clear and coherent body of science before it can be fully recognized or comprehended by either the scientific community or the general public and its representatives: public health officials, regulators, policy makers, and legislators. An attempt at such organization is presented and begins with the premise that there exist clear, objective criteria by which a premiere environmental health issue can be defined. A second premise is that these criteria sort themselves into three categories which cover the full spectrum of toxic contaminant-population relationships. They are: (1) economic and sociopolitical, (2) scientific and public health, and (3) societal risk assessment criteria. The first set of criteria includes economic and historical centrality, primacy of economic over public health considerations, a relatively narrow decision-making framework, and controlled flow of information on the toxicant, especially its negative impacts. The second set of criteria is also orthodox in scope: the toxicant should be indestructible, should accumulate in both the environment and the body, and should be a multimedia contaminant; it should produce toxicity in numerous organs with little impediment; toxicity should be produced with low/no threshold in huge numbers of the most vulnerable; and finally, effects should persist in the critical target organ(s). There is a third, more globally encompassing, set of criteria important for present-day requirements for risk assessment; e.g., the contaminant should produce full-spectrum population-wide as well as individual toxicity. Evidence for societal harm should be compelling. It should typify the increasing importance of the elements of preventive over clinical medicine and the substance should bring to bear the cost-benefit analysis of macro plus micro health risk. Lead exposure and toxicity is conclusively shown to meet ALL of these criteria and is the premiere environmental health threat to America's children.

The use of time-series analysis to forecast bont tick (Amblyomma hebraeum) infestations in Zimbabwe.

Studying the dynamics of tick infestations on cattle is an essential step in developing optimal strategies for tick control. Successful strategic tick control requires accurate predictions of when tick infestations will reach predetermined threshold levels. In the case of Amblyomma hebraeum, earlier work has shown that there is no consistent pattern of seasonal activity. This means that a statistical model for predicting A. hebraeum infestations cannot reliably use climatic factors as the only independent variables. An alternative method is to apply time-series, or auto-regressive moving-average (ARMA), analysis which uses only the past population patterns to predict future trends. This technique was applied to a data set consisting of 108 weekly tick counts of A. hebraeum (adult males, standard females, flat females and standard nymphs), conducted at an experimental station in southeastern Zimbabwe. The ability of the ARMA models to fit and predict actual tick infestations was judged using two sets of criteria. The first set focused on the goodness-of-fit, and used the adjusted R2 values, Q statistic and the Akaike Information Criteria. The second set of criteria measured the forecasting accuracy of an estimated equation, and consisted of regressing a 9-period forecast against an actual out-of-sample data set not used in the estimation process. The root mean square error of the forecast was also considered when comparing several models for the same data set. Using these criteria, the models estimated using the ARMA technique were judged to both fit and forecast with sufficient accuracy to warrant their use in strategic tick control. Although the success of using ARMA to forecast A. hebraeum is partly due to the non-seasonal behavior of the species, the results presented here suggest that it is worthwhile exploring the use of ARMA techniques to model the dynamics of other tick species. Where independent variables exert considerable influence on the dynamics of a tick species, these variables can be incorporated into an ARMA-style model.

Predicting deaths among intensive care unit patients.

Daily APACHE II assessments to reflect the dynamic pathophysiologic processes affecting ICU patients were carried out prospectively on 212 adult ICU admissions for the purpose of predicting hospital outcome. Trend analysis of daily APACHE II scores was used to develop the first set of criteria for predicting deaths among the ICU patients. The analysis took into account the absolute value of APACHE II score of each day and the rate of change relative to that of the previous day. One hundred consecutive adult ICU admissions were used to determine the criteria that were tested on the following 112 consecutive adult ICU admissions. Daily APACHE II scores identified correctly 16 of the 34 patients who died. A second set of criteria was next derived by raising the values of the original limits in order to build-in greater margins of safety without too great a loss of sensitivity. The predictive power of daily APACHE II scores using the second set of criteria was superior to that of a single APACHE II score by a factor of 4. Predictions were not used to influence clinical decision-making during this study.

Improved sex-specific criteria of left ventricular hypertrophy for clinical and computer interpretation of electrocardiograms: validation with autopsy findings.

In a previous study of 543 patients we developed, using echocardiographic left ventricular mass as the reference standard, two new sets of criteria that improve the electrocardiographic diagnosis of left ventricular hypertrophy (LVH). One set of criteria, which is suitable for routine clinical use, detects LVH when the sum of voltage in RaVL + SV3 (Cornell voltage) exceeds 2.8 mV in men and 2.0 mV in women. The second set of criteria, suitable for use in interpretation of the computerized electrocardiogram, uses logistic regression models based on electrocardiographic and demographic variables with independent predictive value for LVH, with separate equations for patients in sinus rhythm and atrial fibrillation. To test these criteria prospectively with use of a different reference standard, antemortem electrocardiograms were compared with left ventricular muscle mass measured at autopsy in 135 patients. Sensitivity of standard Sokolow-Lyon voltage (SLV) criteria (SV1 + RV5 or RV6 greater than 3.5 mV) for LVH was only 22%, but specificity was 100%. The Cornell voltage criteria improved sensitivity to 42%, while maintaining high specificity at 96%. Higher sensitivity (62%) was achieved by use of the new regression criteria, with a specificity of 92%. Overall test accuracy was 60% for SLV criteria, 68% for the Cornell voltage criteria, and 77% for the new regression criteria (p less than .005 vs SLV). We conclude that the Cornell voltage criteria improve the sensitivity of the electrocardiogram for detection of LVH and are easily applicable in clinical practice.(ABSTRACT TRUNCATED AT 250 WORDS)

Tests for the mutagenic action of a number of chemicals on Haemophilus influenzae with special emphasis on hydrazine

A number of chemicals have been tested for their ability to produce novobiocin-resistant mutants in Haemophilus influenzae. Of these, hydrazine (HZ) proved unique because it induced a fairly high incidence of mutation without killing significant numbers of cells at concentrations ranging over nearly four orders of magnitude. Moreover, its dose-effect curve increased very slowly initially and reached a relatively low maximum. It is suggested that HZ may be acting as both a mutagen and an anti-mutagen in this system. HZ has sometimes been characterized as primarily an inactivating agent rather than as a mutagen. Obviously, quite the opposite is true for H. influenzae. Moreover, a survey of the literature shows that HZ has been used effectively to produce mutations in phage, bacteria, higher plants and Drosophila. There is reason to suspect that it produces mainly single locus mutations rather than chromosomal aberrations, but the amount of information on this point is still very small. The effectiveness of a mutagen can be markedly affected by the criterion of effectiveness used. If a high incidence of mutation with reasonably high cell survival is the criterion, then mutagens that are relatively nontoxic would probably be considered highly effective. In this case, the maximum mutation rate that can be achieved in practice may be controlled either by toxicity or by maxima like the one found for HZ. If, on the other hand, the important criteria are the concentration and exposure time needed to produce a detectable increase in mutation, then some quite toxic mutagens would be considered quite effective even though the maximum mutation that can be produced in practice is low. The first criterion is the one to use in choosing mutagens for detailed analysis of the mutation process, but the second set of criteria may be more suitable for generalizing to other organisms, for example from microorganisms to man, since toxic effects can be quite different in different cell types.

Tests for the mutagenic action of a number of chemicals on Haemophilus influenzae with special emphasis on hydrazine

A number of chemicals have been tested for their ability to produce novobiocin-resistant mutants in Haemophilus influenzae. Of these, hydrazine (HZ) proved unique because it induced a fairly high incidence of mutation without killing significant numbers of cells at concentrations ranging over nearly four orders of magnitude. Moreover, its dose-effect curve increased very slowly initially and reached a relatively low maximum. It is suggested that HZ may be acting as both a mutagen and an anti-mutagen in this system. HZ has sometimes been characterized as primarily an inactivating agent rather than as a mutagen. Obviously, quite the opposite is true for H. influenzae. Moreover, a survey of the literature shows that HZ has been used effectively to produce mutations in phage, bacteria, higher plants and Drosophila. There is reason to suspect that it produces mainly single locus mutations rather than chromosomal aberrations, but the amount of information on this point is still very small. The effectiveness of a mutagen can be markedly affected by the criterion of effectiveness used. If a high incidence of mutation with reasonably high cell survival is the criterion, then mutagens that are relatively nontoxic would probably be considered highly effective. In this case, the maximum mutation rate that can be achieved in practice may be controlled either by toxicity or by maxima like the one found for HZ. If, on the other hand, the important criteria are the concentration and exposure time needed to produce a detectable increase in mutation, then some quite toxic mutagens would be considered quite effective even though the maximum mutation that can be produced in practice is low. The first criterion is the one to use in choosing mutagens for detailed analysis of the mutation process, but the second set of criteria may be more suitable for generalizing to other organisms, for example from microorganisms to man, since toxic effects can be quite different in different cell types.

Tests for the mutagenic action of a number of chemicals on Haemophilus influenzae with special emphasis on hydrazine☆

A number of chemicals have been tested for their ability to produce novobiocin-resistant mutants in Haemophilus influenzae. Of these, hydrazine (HZ) proved unique because it induced a fairly high incidence of mutation without killing significant numbers of cells at concentrations ranging over nearly four orders of magnitude. Moreover, its dose-effect curve increased very slowly initially and reached a relatively low maximum. It is suggested that HZ may be acting as both a mutagen and an anti-mutagen in this system. HZ has sometimes been characterized as primarily an inactivating agent rather than as a mutagen. Obviously, quite the opposite is true for H. influenzae. Moreover, a survey of the literature shows that HZ has been used effectively to produce mutations in phage, bacteria, higher plants and Drosophila. There is reason to suspect that it produces mainly single locus mutations rather than chromosomal aberrations, but the amount of information on this point is still very small. The effectiveness of a mutagen can be markedly affected by the criterion of effectiveness used. If a high incidence of mutation with reasonably high cell survival is the criterion, then mutagens that are relatively nontoxic would probably be considered highly effective. In this case, the maximum mutation rate that can be achieved in practice may be controlled either by toxicity or by maxima like the one found for HZ. If, on the other hand, the important criteria are the concentration and exposure time needed to produce a detectable increase in mutation, then some quite toxic mutagens would be considered quite effective even though the maximum mutation that can be produced in practice is low. The first criterion is the one to use in choosing mutagens for detailed analysis of the mutation process, but the second set of criteria may be more suitable for generalizing to other organisms, for example from microorganisms to man, since toxic effects can be quite different in different cell types.

Comagmatism criteria of intrusive, subvolcanic, and effusive rocks (Miao-Chang region)

The first group of criteria involve an intimate and obvious association of the subvolcanics and pyroclastics, strict structural control (emplacement along faults) and gradual transitions from central porphyries to apophyses. The second set of criteria includes the close resemblance in mineral composition of intrusives and extrusives, the nearly equal amounts of rock-forming minerals and common suites of accessory minerals. The third set of criteria involve common elementary compositions of intrusives and extrusives and a demonstrable common elementary composition of both types of rock.