Optimal design of experiments on nematode dynamics and crop yield

Nematology ◽  
2012 ◽  
Vol 14 (7) ◽  
pp. 773-786 ◽  
Author(s):  
Wim van den Berg ◽  
Johan Grasman ◽  
Walter A.H. Rossing
Keyword(s):  
Optimum Design ◽  
Crop Yield ◽  
Regression Models ◽  
Design Theory ◽  
Yield Loss ◽  
Linear Regression Models ◽  
Nematode Density ◽  
Experimental Design Theory ◽  
Side Result

Experimental design theory provides tools to estimate parameters of nematode dynamics and yield loss functions with the highest accuracy given the available budget for the experiment. Variables in models, which take the role of predictors, are given values and a weight so that the best result is obtained. As a side result the prediction of the response will have a minimal variance. We introduce the concept of D-optimum design and consider in our models two response variables: the nematode density at the end of the season and the crop yield. Both variables depend on the same predictor, the initial nematode density. D-optimum design applies to linear regression models. For models that are nonlinear in the parameters, as is the case in this study, a linearisation at a given point in a parameter plane is used. When the initial nematode density at the experimental units is known prior to experimentation, one may optimally allocate the treatments to the units by selecting the combination that has the highest efficiency.

scholarly journals Face mask wearing rate predicts country’s COVID-19 death rates

2020 ◽  
Author(s):  
Daisuke Miyazawa ◽  
Gen Kaneko
Keyword(s):  
Multiple Regression ◽  
Regression Models ◽  
Face Mask ◽  
Lasso Regression ◽  
Regression Analyses ◽  
Linear Regression Models ◽  
National Differences ◽  
Regression Approach ◽  
Independent Risk Factors

AbstractIdentification of biomedical and socioeconomic predictors for the number of deaths by COVID-19 among countries will lead to the development of effective intervention. While previous multiple regression studies have identified several predictors, little is known for the effect of mask non-wearing rate on the number of COVID-19-related deaths possibly because the data is available for limited number of countries, which constricts the application of traditional multiple regression approach to screen a large number of potential predictors. In this study, we used the hypothesis-driven regression to test the effect of limited number of predictors based on the hypothesis that the mask non-wearing rate can predict the number of deaths to a large extent together with age and BMI, other relatively independent risk factors for hospitalized patients of COVID-19. The mask non-wearing rate, percentage of age ≥ 80 (male), and male BMI showed Spearman’s correlations up to about 0.8, 0.7, and 0.6 with the number of deaths per million from 22 countries from mid-March to mid-June, respectively. The observed number of deaths per million were significantly correlated with the numbers predicted by the lasso regression model including four predictors, age ≥ 80 (male), male BMI, and mask non-wearing rates from mid-March and late April to early May (Pearson’s coefficient = 0.918). The multiple linear regression models including the mask non-wearing rates, age, and obesity-related predictors explained up to 79% variation of the number of deaths per million. Furthermore, 56.8% of the variation of mask non-wearing rate in mid-March, the strongest predictor of the number of deaths per million, was predicted by age ≥ 80 (male) and male BMI, suggesting the confounding role of these predictors. Although further verification is needed to identify causes of the national differences in COVID-19 mortality rates, these results highlight the importance of the mask, age, and BMI in predicting the COVID-19-related deaths, providing a useful strategy for future regression analyses that attempt to contribute to the mechanistic understanding of COVID-19.

scholarly journals The Influence of Sitting, Standing, and Stepping Bouts on Cardiometabolic Health Markers in Older Adults

2021 ◽  
pp. 1-9
Author(s):  
Simone J.J.M. Verswijveren ◽  
Cormac Powell ◽  
Stephanie E. Chappel ◽  
Nicola D. Ridgers ◽  
Brian P. Carson ◽  
...  
Keyword(s):  
Physical Activity ◽  
Older Adults ◽  
Body Composition ◽  
Linear Regression ◽  
Regression Models ◽  
Fasting Glucose ◽  
Cardiometabolic Health ◽  
Linear Regression Models ◽  
Cross Sectional

Aside from total time spent in physical activity behaviors, how time is accumulated is important for health. This study examined associations between sitting, standing, and stepping bouts, with cardiometabolic health markers in older adults. Participants from the Mitchelstown Cohort Rescreen Study (N = 221) provided cross-sectional data on activity behaviors (assessed via an activPAL3 Micro) and cardiometabolic health. Bouts of ≥10-, ≥30-, and ≥60-min sitting, standing, and stepping were calculated. Linear regression models were fitted to examine the associations between bouts and cardiometabolic health markers. Sitting (≥10, ≥30, and ≥60 min) and standing (≥10 and ≥30 min) bouts were detrimentally associated with body composition measures, lipid markers, and fasting glucose. The effect for time spent in ≥60-min sitting and ≥30-min standing bouts was larger than shorter bouts. Fragmenting sitting with bouts of stepping may be targeted to benefit cardiometabolic health. Further insights for the role of standing need to be elicited.

Skipping breakfast and mood: The role of sleep

2021 ◽  
pp. 026010602098486
Author(s):  
Zon-Shuan Chang ◽  
Ali Boolani ◽  
Deirdre A. Conroy ◽  
Tom Dunietz ◽  
Erica C. Jansen
Keyword(s):  
Linear Regression ◽  
Regression Models ◽  
Mood States ◽  
Poor Sleep ◽  
Linear Regression Models ◽  
Night Time ◽  
Breakfast Skipping ◽  
Time Awake ◽  
Skipping Breakfast

Background: Breakfast skipping has been related to poor mood, but the role of sleep in this relationship remains unclear. Aim: To evaluate whether breakfast skipping associated with mood independently of sleep, and whether sleep interacted with breakfast skipping. Methods: During an in-person research visit, a sample of 329 adults completed questionnaires regarding last night’s sleep, current morning breakfast intake, and mid-morning mood states. Sex-stratified linear regression models examined associations between breakfast skipping and mood and interactions with sleep. Results: Among males, those who did not consume breakfast had less vigor independent of sleep (β=−2.72 with 95% CI −4.91, −0.53). Among females, those who did not consume breakfast had higher feelings of anxiety (β=1.21 with 95% CI −0.04, 2.47). Interaction analyses revealed that males with longer time to fall asleep and longer night-time awake time had higher depression scores in the presence of breakfast skipping, and females with more night-time awake time and shorter duration had higher fatigue and less vigor if they were also breakfast skippers. Conclusion: Breakfast skipping and poor sleep may jointly affect mood.

scholarly journals SELF-RATED HEALTH AS A PREDICTOR OF DEPRESSION AND ANXIETY IN OLDER ADULT INMATES

2019 ◽  
Vol 3 (Supplement_1) ◽  
pp. S166-S166
Author(s):  
Carlyn E Vogel ◽  
Lisa C Barry
Keyword(s):  
Regression Models ◽  
Continuous Variable ◽  
High Risk Population ◽  
Correctional Facilities ◽  
Depression And Anxiety ◽  
Linear Regression Models ◽  
Face To Face ◽  
Self Rated Health ◽  
Older Inmates

Abstract Inmates age ≥50 years (older inmates) are a rapidly growing population within the U.S. correctional system with the highest suicide rate among adult prisoners. Although depression and anxiety are strong precursors of subsequent suicide, little is known regarding factors associated with these outcomes in older inmates. To inform suicide prevention efforts in this high-risk population, we evaluated the role of older inmates’ self-rated health (SRH) in relation to depression and anxiety. We utilized data from the ongoing Aging Inmates Suicidal Ideation and Depression study (Aging INSIDE). Participants (N=175) included men age ≥50 (M=56.5, SD=6.3, range=50-79 years) from eight correctional facilities in Connecticut who completed face-to-face interviews. The outcomes, depression and anxiety, were assessed using the PHQ-9 (range 0-27) and GAD-7 (range 0-21); higher scores on each scale indicated worsening severity. SRH, operationalized as a pseudo-continuous variable (1=excellent; 5=Poor), was correlated with depression (r=0.379; p <.001) and anxiety (r=0.260; p =.001) in unadjusted analyses. Two linear regression models were conducted to determine if SRH was associated with depression and/or anxiety after controlling for age, race (white versus non-white), years of education, visitors (yes versus no), and number of chronic conditions. Increasingly worse SRH was significantly associated with more depressive symptoms (β=1.92, SE=.43, p <.001) and higher anxiety scores (β=1.41, SE=.41, p=.001). SRH explained 10.0% and 6.2% of the variance in depression and anxiety scores, respectively. SRH may be useful for identifying older inmates who are more likely to have depression or anxiety, and thus may be at higher risk for suicide.

Estimated soybean (Glycine max) yield loss from herbicide damage using ground cover or rated stunting

Weed Science ◽  
1998 ◽  
Vol 46 (4) ◽  
pp. 454-458 ◽  
Author(s):  
W. W. Donald
Keyword(s):  
Linear Regression ◽  
Regression Models ◽  
Yield Loss ◽  
Ground Cover ◽  
Crop Damage ◽  
Linear Regression Equation ◽  
Linear Regression Models ◽  
Soybean Yield ◽  
Independent Variable ◽  
Model Variability

The primary goal of this research was to determine whether crop damage from herbicides measured soon after treatment could estimate relative crop yield loss. Two to 4 wk after spraying soybeans with an unregisrered mixture of rhifensulfuron plus sethoxydim at various rates plus crop oil concentrate, percent stunting was visually rated and percent projected ground cover of soybeans was determined from photographs. In each of 3 yr, relative percent soybean yield was a negative linear function of relative herbicide rate from 0.25× to 2× the registered (1×) rate. The 1× rate of thifensulfuron and sethoxydim was 17.5 and 420 g ai ha−1, respectively. Relative soybean yield was also negatively related linearly to stunting but positively related linearly to soybean ground cover over 3 yr. Linear regression equation models of relative soybean yield versus percent soybean ground cover explained more model variability, more consistently (R2≥ 0.60 in two of 3 yr) than did either stunting (R2≥ 0.60 in one of 3 yr) or relative herbicide rate (R2= 0.37 to 0.48 over 3 yr). However, linear regression models for each independent variable differed from year to year and were related to differences in rainfall following treatment. Ways are suggested to increase regression model precision and between-year reproducibility.

Sitting Time, Physical Activity, and Cardiorespiratory Fitness: Cooper Center Longitudinal Study Cohort

2016 ◽  
Vol 13 (1) ◽  
pp. 17-23 ◽  
Author(s):  
Carolyn E. Barlow ◽  
Kerem Shuval ◽  
Bijal A. Balasubramanian ◽  
Darla E. Kendzor ◽  
Kelley Pettee Gabriel
Keyword(s):  
Physical Activity ◽  
Longitudinal Study ◽  
Cardiorespiratory Fitness ◽  
Regression Models ◽  
Sitting Time ◽  
Study Cohort ◽  
Linear Regression Models ◽  
Cross Sectional ◽  
Prolonged Sitting

Background:Prolonged sitting time is associated with numerous health outcomes; however, the role of cardiorespiratory fitness (CRF) in these relationships is largely unexplored. The cross-sectional association between reported sitting time and measured CRF was examined in a large study of healthy men and women.Methods:The analytic sample included 4658 men and 1737 women enrolled in the Cooper Center Longitudinal Study. Unadjusted and adjusted multivariable linear regression models were constructed to examine the association between sitting time and CRF, stratified by sex and meeting (or not) meeting physical activity (PA) guidelines.Results:In men, CRF was not associated with sitting time after adjustment for potential confounders. In contrast, for women, after adjustment there was a significant association between increased sitting time and lower CRF (P for trend <.001). When stratified by meeting or not meeting PA guidelines, there was no association between sitting time and CRF in men. In women, this relationship was statistically significant regardless of PA category (both P for trend < .05).Conclusions:These results suggest that the association between sitting time and CRF varies by sex. Further, meeting PA guidelines does not appear to modify this relation in either sex.

scholarly journals Do Tax Knowledge, Level of Trust, and Religiosity De-termine Compliance to Pay Property Tax?

2021 ◽  
Vol 4 (1) ◽  
pp. 67-75
Author(s):  
Sakirin Sakirin ◽  
Darwanis Darwanis ◽  
Syukriy Abdullah
Keyword(s):  
Regression Models ◽  
Design Methodology ◽  
Property Tax ◽  
Sampling Technique ◽  
Primary Data ◽  
Knowledge Level ◽  
Linear Regression Models ◽  
Role Of Religion ◽  
Tax Payers

Objective – This study aims to test the effect of tax knowledge, level of trust and religiosity on taxpayers' compliance in paying property tax (PBB) in Aceh Singkil Regency, Aceh, Indonesia.  Design/methodology – The population of this study are all property taxpayers in Aceh Singkil Regency for the year 2018 with a total of 34,000 taxpayers. Non-probability sampling technique was utilized to draw the research sample which results in 396 samples. Primary data was obtained through questionnaires distributed to the respondents and analyzed using multiple linear regression models.  Results – The results showed that tax knowledge, level of trust and religiosity affect the compliance of the taxpayers of property tax in Aceh Singkil Regency, Indonesia. Partially, tax knowledge affects the compliance of property tax paying of taxpayers while the level of trust affects the compliance to pay property tax of taxpayers in Aceh Singkil Regency. Nevertheless religiosity does not affect the compliance of paying property tax of taxpayers in Aceh Singkil Regency. The findings of this study interestingly provides an evidence of the lack of role of religion in influencing the tax payers’ compliance towards property tax.

scholarly journals ELEVATED SERUM PENTRAXIN-3 LEVELS IS POSITIVELY CORRELATED TO DISEASE SEVERITY AND COAGULOPATHY IN COVID-19 PATIENTS

2020 ◽  
Vol 13 (1) ◽  
pp. e2021015
Author(s):  
Ming Tong ◽  
Ying Xiong ◽  
Chen Zhu ◽  
Hong Xu ◽  
Qing Zheng ◽  
...  
Keyword(s):  
Disease Severity ◽  
Regression Models ◽  
Elevated Serum ◽  
Coefficient Of Determination ◽  
Pentraxin 3 ◽  
Linear Regression Models ◽  
Potential Therapeutic Target ◽  
Ptx3 Level ◽  
D Dimer

Abstract BACKGROUND Coronavirus disease 2019 (COVID-19) is highly contagious and deadly and is associated with coagulopathy. Pentraxin-3(PTX3) participates in innate resistance to infections and plays a role in thrombogenesis. PURPOSE The present study aimed to investigate the role of PTX3 in coagulopathy in patients with COVID-19. METHODS A retrospective study including thirty-nine COVID-19 patients enrolled in Hunan, China were performed. The patients were classified into the D-dimer_L (D-dimer?1mg/L) and D-dimer_H (D-dimer?1mg/L) groups basing on the plasma D-dimer levels on admission. Serum PTX3 levels were detected by enzyme-linked immunosorbent assays and compared between those two groups, and then linear regression models were applied to analyze the association between PTX3 and D-dimer. RESULTS Our results showed that serum PTX3 levels (median values, 10.21 vs 3.36, P < 0.001), chest computerized tomography scores (median values, 10.0 vs 9.0, P < 0.05), and length of stay (16.0±4.2 vs 10.7±3.6, P = 0.001) in the D-dimer_H group were significantly higher than that in D-dimer_L group. The coefficient of determination for PTX3 was 0.651 (P < 0.001) in the D-dimer_H group. CONCLUSION Serum level of PTX3 was positively correlated with disease severity and coagulopathy. Detection of serum PTX3 level could assist to identify severer patients on admission and may be a potential therapeutic target for coagulopathy in patients with COVID-19.

scholarly journals The role of iron and nickel smelters for the Indonesian steel industries

2021 ◽  
Vol 882 (1) ◽  
pp. 012076
Author(s):  
D Cahyaningtyas ◽  
T Suseno ◽  
S Rochani ◽  
B Yunianto ◽  
I Rodliyah ◽  
...  
Keyword(s):  
Regression Models ◽  
Raw Materials ◽  
National Development ◽  
Steel Production ◽  
Trade Deficit ◽  
Linear Regression Models ◽  
Iron And Steel ◽  
Fe Content ◽  
Steel Industries

Abstract The iron and steel industries play a crucial role in supporting national development. The high dependence on imported raw materials causes Indonesia to suffer US $ 2.11 billion steel trade deficit per year. This study identifies the role of iron and nickel smelters in supporting the development of steel industries. The methodology used is descriptive statistics and regression models. Ferronickel and nickel pig iron as the primary raw materials for stainless steel have been produced in Indonesia, but only 23.05% and 47.77% are sold domestically. According to the linear regression models, it is expected that steel production and consumption will grow. Indonesia will become an independent steel producer and even export it by 2050. However, the supply chain is weak and poorly integrated as the local raw materials do not meet the domestic steel industry’s specifications. By 2050, 44 million tonnes of scrap, 19 million tonnes of sponge iron, 16 million tonnes of nickel, and 10 million tonnes of other raw materials will be needed annually. Hence, to reduce the national steel trade deficit, Indonesia must increase the smelters capacity and optimize local iron resources by increasing Fe content to meet the specifications of the national steel industry.

scholarly journals Role of irisin in Chinese patients with hypothyroidism: an interventional study

2019 ◽  
Vol 47 (4) ◽  
pp. 1592-1601 ◽  
Author(s):  
Ning Yang ◽  
Heng Zhang ◽  
Xia Gao ◽  
Li Miao ◽  
Zhi Yao ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Regression Models ◽  
Free Thyroxine ◽  
Chinese Patients ◽  
Control Group ◽  
Linear Regression Models ◽  
Interventional Study ◽  
Free Triiodothyronine ◽  
Levothyroxine Treatment

Objective Irisin is a myokine that greatly affects energy expenditure and systemic metabolism. While thyroid hormone is likely associated with irisin, a direct relationship remains to be fully elucidated. This study aimed to investigate plasma irisin levels in Chinese patients with hypothyroidism. Methods A total of 155 subjects were divided into the hypothyroidism group or the control group. Fifty-seven patients in the hypothyroidism group received levothyroxine treatment. Baseline irisin levels were measured in the two groups and post-treatment levels were measured in the hypothyroidism group. Results Irisin levels were significantly lower in the hypothyroidism group than in the control group. In the hypothyroidism group, irisin levels were positively associated with free triiodothyronine and free thyroxine levels, and negatively associated with thyrotropin levels. In the hypothyroidism group, irisin levels were significantly increased after levothyroxine treatment. Multiple linear regression models showed that total cholesterol and free thyroxine levels were the only significant predictors of serum irisin levels. Conclusions Irisin levels are decreased in patients with hypothyroidism. Our results suggest that decreased irisin levels are directly associated with reduced thyroid hormone levels. These values may be restored after levothyroxine treatment in Chinese patients with hypothyroidism.

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