scholarly journals Estimating species sensitivity distributions on the basis of readily obtainable descriptors and toxicity data for three species of algae, crustaceans, and fish

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10981
Author(s):  
Yuichi Iwasaki ◽  
Kiyan Sorgog
Keyword(s):  
Regression Models ◽  
External Validation ◽  
Model Fitting ◽  
Toxicity Data ◽  
Linear Regression Models ◽  
Species Sensitivity ◽  
Hazardous Concentration ◽  
The Mean ◽  
Two Parameters ◽  
Species Sensitivity Distributions

Estimation of species sensitivity distributions (SSDs) is a crucial approach to predicting ecological risks and water quality benchmarks, but the amount of data required to implement this approach is a serious constraint on the application of SSDs to chemicals for which there are few or no toxicity data. The development of statistical models to directly estimate the mean and standard deviation (SD) of the logarithms of log-normally distributed SSDs has recently been proposed to overcome this problem. To predict these two parameters, we developed multiple linear regression models that included, in addition to readily obtainable descriptors, the mean and SD of the logarithms of the concentrations that are acutely toxic to one algal, one crustacean, and one fish species, as predictors. We hypothesized that use of the three species’ mean and SD would improve the accuracy of the predicted means and SDs of the logarithms of the SSDs. We derived SSDs for 60 chemicals based on quality-assured acute toxicity data. Forty-five of the chemicals were used for model fitting, and 15 for external validation. Our results supported previous findings that models developed on the basis of only descriptors such as log KOW had limited ability to predict the mean and SD of SSD (e.g., r2 = 0.62 and 0.49, respectively). Inclusion of the three species’ mean and SD, in addition to the descriptors, in the models markedly improved the predictions of the means and SDs of SSDs (e.g., r2 = 0.96 and 0.75, respectively). We conclude that use of the three species’ mean and SD is promising for more accurately estimating an SSD and thus the hazardous concentration for 5% of species in cases where limited ecotoxicity data are available.

scholarly journals Assessing Early Heterogeneity in Doubling Times of the COVID-19 Epidemic across Prefectures in Mainland China, January–February, 2020

Epidemiologia ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 95-113 ◽  
Author(s):  
Isaac Chun-Hai Fung ◽  
Xiaolu Zhou ◽  
Chi-Ngai Cheung ◽  
Sylvia K. Ofori ◽  
Kamalich Muniz-Rodriguez ◽  
...  
Keyword(s):  
Regression Models ◽  
Doubling Time ◽  
Metropolitan Areas ◽  
Mainland China ◽  
Linear Regression Models ◽  
Case Count ◽  
Daily Time Series ◽  
The Mean ◽  
Doubling Times ◽  
Daily Time

To describe the geographical heterogeneity of COVID-19 across prefectures in mainland China, we estimated doubling times from daily time series of the cumulative case count between 24 January and 24 February 2020. We analyzed the prefecture-level COVID-19 case burden using linear regression models and used the local Moran’s I to test for spatial autocorrelation and clustering. Four hundred prefectures (~98% population) had at least one COVID-19 case and 39 prefectures had zero cases by 24 February 2020. Excluding Wuhan and those prefectures where there was only one case or none, 76 (17.3% of 439) prefectures had an arithmetic mean of the epidemic doubling time <2 d. Low-population prefectures had a higher per capita cumulative incidence than high-population prefectures during the study period. An increase in population size was associated with a very small reduction in the mean doubling time (−0.012, 95% CI, −0.017, −0.006) where the cumulative case count doubled ≥3 times. Spatial analysis revealed high case count clusters in Hubei and Heilongjiang and fast epidemic growth in several metropolitan areas by mid-February 2020. Prefectures in Hubei and neighboring provinces and several metropolitan areas in coastal and northeastern China experienced rapid growth with cumulative case count doubling multiple times with a small mean doubling time.

Abstract WMP14: Association of Systolic Blood Pressure, LDL Cholesterol, and Hgb A1c With White Matter Hyperintensity on MRI in the ACCORDION MIND Study

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Adam H de Havenon ◽  
Tanya Turan ◽  
Rebecca Gottesman ◽  
Sharon Yeatts ◽  
Shyam Prabhakaran ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Risk Factor ◽  
Regression Models ◽  
Ldl Cholesterol ◽  
Vascular Risk Factor ◽  
White Matter Hyperintensity ◽  
Vascular Risk ◽  
Linear Regression Models ◽  
Risk Factor Profile ◽  
The Mean

Introduction: While retrospective studies have shown that poor control of vascular risk factors is associated with progression of white matter hyperintensity (WMH), it has not been studied prospectively. Hypothesis: We hypothesize that higher systolic blood pressure (SBP) mean, LDL cholesterol, and Hgb A1c will be correlated with WMH progression in diabetics. Methods: This is a secondary analysis of the Memory in Diabetes (MIND) substudy of the Action to Control Cardiovascular Risk in Diabetes Follow-on Study (ACCORDION). The primary outcome was WMH progression, evaluated by fitting linear regression models to the WMH volume on the month 80 MRI and adjusting for the WMH volume on the baseline MRI. The primary predictors were the mean values of SBP, LDL, and A1c from baseline to month 80. We defined a good vascular risk factor profile as mean SBP <120 mm Hg and mean LDL <120 mg/dL. Results: We included 292 patients, with a mean (SD) age of 62.6 (5.3) years and 55.8% male. The mean number of SBP, LDL, and A1c measurements per patient was 17, 5, and 12. We identified 86 (29.4%) patients with good vascular risk factor profile. In the linear regression models, mean SBP and LDL were associated with WMH progression and in a second fully adjusted model they both remained associated with WMH progression (Table). Those with a good vascular risk factor profile had less WMH progression (β Coefficient -0.80, 95% CI -1.42, -0.18, p=0.012). Conclusions: Our data reinforce prior research showing that higher SBP and LDL is associated with progression of WMH in diabetics, likely secondary to chronic microvascular ischemia, and suggest that control of these factors may have protective effects. This study has unique strengths, including prospective serial measurement of the exposures, validated algorithmic measurement methodology for WMH, and rigorous adjudication of study data. Clinical trials are needed to investigate the effect of vascular risk factor reduction on WMH progression.

Species Sensitivity Distributions for Nonylphenol to Estimate Soil Hazardous Concentration

2017 ◽  
Vol 51 (23) ◽  
pp. 13957-13966 ◽  
Author(s):  
Jin Il Kwak ◽  
Jongmin Moon ◽  
Dokyung Kim ◽  
Rongxue Cui ◽  
Youn-Joo An
Keyword(s):  
Species Sensitivity ◽  
Hazardous Concentration ◽  
Species Sensitivity Distributions

scholarly journals Trends in the Cumulative Incidence of Vocational Rehabilitation Indicators in Brazil, 2007–2016

2020 ◽  
Vol 17 (11) ◽  
pp. 3952
Author(s):  
Cristiano Barreto de Miranda ◽  
João Silvestre Silva-Junior ◽  
Gisele Aparecida Fernandes ◽  
Frida Marina Fischer
Keyword(s):  
Open Access ◽  
Confidence Interval ◽  
Vocational Rehabilitation ◽  
Cumulative Incidence ◽  
Regression Models ◽  
Linear Regression Models ◽  
Disability Benefits ◽  
The Public ◽  
Increasing Trend ◽  
The Mean

Vocational rehabilitation (VR) aims at improving work ability to facilitate workers’ return to work. VR is provided in Brazil by the public social security system. The aim of the present study was to analyze trends in VR indicators for Brazil from 2007 to 2016. Based on open-access, secondary aggregate data, we calculated the cumulative incidence of VR indicators. We fitted Prais-Winsten generalized linear regression models to estimate trends and calculated annual percent variation with the corresponding 95% confidence interval (95% CI). The mean cumulative incidence of referrals to VR services was 37.16/1000 temporary disability benefits granted and exhibited a decreasing trend of −6.92% (95% CI: −8.38; −5.43). The mean cumulative incidence of admissions to VR services was 57.34/100 referrals and exhibited an increasing trend of 3.31% (95% CI: 1.13; 5.53). The mean cumulative incidence of rehabilitation was 57.43/100 admissions and remained stable along the analyzed period, −2.84 (95% CI: −5.87; 0.29). Our findings evidence a reduction in the number of workers referred for VR, an increase of admissions, and stability in the cumulative incidence of rehabilitated workers.

scholarly journals Sun exposure and intima-media thickness in the Mexican Teachers' Cohort

2020 ◽  
Author(s):  
Mercedes Aguilar ◽  
Paloma Muñoz-Aguirre ◽  
Adrian Cortés-Valencia ◽  
Mario H. Flores-Torres ◽  
Andrés Catzin-Kuhlmann ◽  
...  
Keyword(s):  
Regression Models ◽  
Carotid Atherosclerosis ◽  
Sun Exposure ◽  
Intima Media Thickness ◽  
Linear Regression Models ◽  
Positive Role ◽  
Cross Sectional ◽  
Media Thickness ◽  
Percentage Difference ◽  
The Mean

Abstract Background Previous studies have evaluated how sun exposure affects cardiovascular health. In this sense, some evidence from ecological studies have found an inverse relationship between sun exposure and blood pressure or CVD. The aim of this study is to determine whether long-term sun exposure has a protective role in subclinical cardiovascular disease in adult Mexican women. Methods We conducted a cross-sectional analysis of a sample of women from the Mexican Teachers’ Cohort (MTC) study. Sun exposure was assessed in the MTC 2008 baseline questionnaire, in which women were asked about their sun-related behavior. Vascular neurologists measured carotid intima-media thickness (IMT) using standard techniques. Multivariate linear regression models were used to estimate the percentage difference in mean IMT and 95% confidence intervals (95% CIs), according to categories of sun exposure and multivariate logistic regression models were used to estimate the odds ratio (OR) and 95% CIs for carotid atherosclerosis. Results The mean age of participants was 49.6 ± 5.5 years, the mean IMT was 0.678 ± 0.097 mm, and the mean accumulated hours of weekly sun exposure were 2.9 ± 1.9. Prevalence of carotid atherosclerosis was 20.9%. Compared to women in the lowest category of sun exposure, the multivariate adjusted ORs of carotid atherosclerosis were 0.54 (95%CI: 0.24, 1.18) for women who were exposed 9 hours. For women who denied regular sun screen use, those in the higher exposure category (9 hours) had lower mean IMT compared to those in the lower category (multivariable-adjusted mean % difference = -2.67; 95%CI: -6.9, -1.5). Conclusion In general, we observed that cumulative sun exposure was inversely associated with IMT and subclinical carotid atherosclerosis. Our findings suggest that public health messages should also consider the sun’s positive role for health, while still emphasizing the negative impacts of excessive exposure.

scholarly journals Previous COVID-19 infection and antibody levels after vaccination

2021 ◽  
Author(s):  
Hamad Ali ◽  
Barrak Alahmad ◽  
Abdullah A. Al-Shammari ◽  
Abdelmohsen Al-Terki ◽  
Maha Hammad ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Regression Models ◽  
Individual Characteristics ◽  
Linear Regression Models ◽  
Serological Analysis ◽  
Health Authorities ◽  
Public Health Authorities ◽  
The Mean ◽  
Vaccine Shortages ◽  
Antibody Levels

AbstractBackgroundThe emergence of new COVID-19 variants of concern coupled with a global inequity in vaccine access and distribution, prompted many public health authorities to circumvent the vaccine shortages by altering vaccination protocols and prioritizing high-risk individuals. Those with previous COVID-19 infection may have not been prioritized due to existing humoral immunity.ObjectiveWe aim to study the association between previous COVID-19 infection and antibody levels after COVID-19 vaccination.MethodsA serological analysis to measure SARS-CoV-2 IgG, IgA and neutralizing antibodies was performed on individuals who received one or two doses of either BNT162b2 or ChAdOx1 vaccines in Kuwait. Generalized linear regression models adjusted for individual characteristics and comorbidities were fitted to study the average levels of IgG and neutralizing antibodies in vaccinated individuals based who had previous COVID-19 infection compared to those who had not.ResultsA total of 1025 individuals were recruited. The mean levels of IgG, IgA and neutralizing antibodies were higher in vaccinated subjects with previous COVID-19 infection when compared with those vaccinated without previous COVID-19 infection. Regression analysis showed a steeper slope of decline for IgG in vaccinated individuals without previous COVID-19 infection in comparison with vaccinated individuals with previous COVID-19 infection.ConclusionPrevious COVID-19 infection appears to elicit robust and sustained levels of SARS-CoV-2 antibodies in vaccinated individuals. Given the inconsistent supply of COVID-19 vaccines in many countries due to the global inequity, our results point towards wider vaccination plans to especially cover individuals without previous COVID-19 infection.

Computed Tomographic Measurement of Trochlear Depth in Three Breeds of Brachycephalic Dog

2020 ◽  
Author(s):  
Alexandra Matchwick ◽  
Janis P. Bridges ◽  
Benjamin Mielke ◽  
Matthew J. Pead ◽  
Andrew Phillips ◽  
...  
Keyword(s):  
At Risk ◽  
Regression Models ◽  
Published Data ◽  
Linear Regression Models ◽  
Computed Tomographic ◽  
Mixed Breed ◽  
Significant Difference ◽  
French And English ◽  
The Mean ◽  
Tomographic Measurement

Abstract Objective The aim of this study was to determine the trochlear sulcus depth of three common brachycephalic breeds at risk of medial patellar luxation. Study Design Retrospective blinded clinical study using a previously validated ratio (T/P) of maximal trochlear sulcus depth (T) and maximal patellar craniocaudal thickness (P) measured on computed tomography, to assess trochlear sulcus depth in Pugs, French Bulldogs and English Bulldogs without clinical patellar luxation. The effect of breed on T/P was assessed using one-way linear regression models. Results The mean T/P was affected by breed (p < 0.001). There was significant difference between Pugs (0.45) and French Bulldogs (0.38) and between Pugs and English Bulldogs (0.4). There was no significant difference between Pugs and previously published data for non-brachycephalic and mixed breed dogs (0.46) (p = 0.39). Mean T/P was significantly reduced in the brachycephalic dog breeds combined compared with the previously published data (p < 0.001). Conclusion The trochlear sulcus varies by breed and was more shallow in French and English Bulldogs than Pugs, hence a shallow sulcus may be a breed-driven characteristic. The three breeds assessed are at risk of patellar luxation but sulcus depth did not directly correlate with previously published risk factors—the contribution of sulcus depth to the aetiopathogenesis of patellar luxation remains unclear. Trochlear recession to achieve patellar coverage of 50% may be excessive considering maximal breed normal depth.

The rapid estimation of the layer charges of 2:1 expanding clays from a single alkylammonium ion expansion

Clay Minerals ◽  
1990 ◽  
Vol 25 (1) ◽  
pp. 39-50 ◽  
Author(s):  
A. C. Olis ◽  
P. B. Malla ◽  
L. A. Douglas
Keyword(s):  
Regression Models ◽  
Empirical Method ◽  
Layer Charge ◽  
Simple Linear Regression ◽  
Linear Regression Models ◽  
Rapid Estimation ◽  
Before And After ◽  
The Mean ◽  
Long Chain ◽  
Exchange Technique

AbstractAn empirical method to estimate rapidly both mean total layer charge and location of charge in smectites and vermiculites is presented, involving exchange with a long-chain alkylammonium ion before and after the Greene-Kelly test. The method utilizes an empirically determined relationship between XRD basal spacings and the mean layer charges calculated from the conventional n-alkylammonium ion-exchange technique using simple linear regression models to describe the relationships for both monolayer-bilayer and bilayer-pseudotrimolecular layer transitions. The method provides a rapid estimation of these charge parameters and facilitates the proper identification of both smectites and vermiculites consistent with the AIPEA criteria for classification based on total layer charge. It is considered superior to conventional methods of differentiation based mainly on expansion and collapse behaviour.

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