multivariate regression tree
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2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Agostino Accardo ◽  
Lorenzo Pascazio ◽  
Fulvia Costantinides ◽  
Fabio Gorza ◽  
Giulia Silveri

Abstract Background Sublingual varices (SV) are dilatations of tortuous veins that increased with age. Previous studies showed that this pathology could be correlated to some risk factors such as hypertension, age, gender and diabetes mellitus. In this study we evaluated, on a large number of subjects, the relationship between SV and different grades of hypertension as well as some risk factors extending the analysis to new risk factors such as dyslipidemia, obesity and antihypertensive therapy, modelling a possible dependence of SV on all these factors. Methods In the study 1008 subjects, 284 with and 724 without SV, were examined. The blood pressure was measured in office condition and, to exclude subjects with white coat syndrome or masked hypertension, also using a 24 h Holter pressure monitor. Hypertensive subjects were divided in resistant, drugs controlled (compensated) and patients with prior unknown hypertension (new diagnosed) groups. The presence or absence of SV as well as of the risk factors was assessed clinically. We tested the influence of age on the presence of SV by using the chi-square test and the relation between each risk factor and SV by the Cochran–Mantel–Haenszel test. Finally, we carried out a multivariate regression tree analysis in order to predict the presence of SV. Results We confirmed the influence of age on SV and found a significant relationship between SV and both the compensated and resistant hypertension grades. We highlighted a relationship between SV and dyslipidemia in subjects with new diagnosed hypertension, and between SV and smoking in subjects with compensated hypertension grade. The regression tree showed a classification accuracy of about 75% using as variables hypertension grades, age and antihypertensive treatment. Conclusions We confirmed the SV dependence on age, resistant hypertension and smoking, highlighting a new association with dyslipidemia in new diagnosed hypertensive subjects and new relations depending on the hypertension grades. Thus, the SV inspection could be used to suggest a lipidologist as well as a hypertension specialist visit for a pharmacological and pressure check particularly in subjects presenting SV and dyslipidemia. However, further parameters are to be considered to improve the sensitivity of the prognostic tree model.


2021 ◽  
Vol 12 ◽  
Author(s):  
Huan Gao ◽  
Sen Li ◽  
Fengzhi Wu

Diazotrophs are important soil components that help replenish biologically available nitrogen (N) in the soil and contribute to minimizing the use of inorganic N fertilizers in agricultural ecosystems. However, there is little understanding of how diazotrophs respond to intercropping and soil physicochemical properties in cucumber continuous cropping systems. In this study, using the nifH gene as a marker, we have examined the impacts of seven intercropping plants on diazotrophic community diversity and composition compared to a cucumber continuous cropping system during two cropping seasons. The results showed that intercropping increased the abundance of the nifH gene, which was negatively correlated with available phosphorous in the fall. Diazotrophic diversity and richness were higher in the rape–cucumber system than in the monoculture. Multivariate regression tree analysis revealed that the diversity of the diazotrophic communties was shaped mainly by soil moisture and available phosphorous. Skermanella were the dominant genera in all of the samples, which increased significantly in the mustard–cucumber system in the fall. There was no effect of intercropping on the structure of the diazotrophic community in this case. Non-metric multidimensional scaling analysis showed that cropping season had a greater effect than intercropping on the community structure of the diazotrophs. Overall, our results suggest that intercropping altered the abundance and diversity rather than the structure of the diazotrophic community, which may potentially affect the N fixation ability of continuous cropping systems.


2020 ◽  
Author(s):  
Agostino Accardo ◽  
Lorenzo Pascazio ◽  
Fulvia Costantinides ◽  
Fabio Gorza ◽  
Giulia Silveri

Abstract Background: Sublingual varices (SV) are dilatations of tortuous veins that increased with age. Previous studies showed that this pathology could be correlated to some risk factors such as hypertension, age, gender and diabetes mellitus. The goal of the study was to evaluate the relationship between SV and different grades of hypertension as well as other risk factors partially verifying the results of previous studies on a greater number of subjects and extending the analysis to new risk factors such as dyslipidemia, obesity and antihypertensive therapy, modelling a possible dependence of SV on all these factors.Methods: The study was conducted on 1008 subjects (284 with and 724 without sublingual varices). The blood pressure was measured in office condition and, to exclude subjects with white coat syndrome or masked hypertension, also using a 24h Holter pressure monitor. Hypertensive subjects were divided in resistant, drugs controlled (compensated) and patients with prior unknown hypertension (new diagnosed) groups. The presence or absence of SV as well as of the risk factors was assessed clinically. We tested the influence of age on the presence of SV by using the chi-square test, and evaluated the relation between each risk factor and SV by the Cochran-Mantel-Haenszel test. Finally, we carried out a multivariate regression tree analysis in order to predict the presence of SV.Results: We confirmed the influence of age on SV and found a significant relationship between SV and both the compensated and resistant hypertension grades. Moreover, we highlighted a relationship between SV and dyslipidemia, only in subjects with new diagnosed hypertension, and between SV and smoking, in new diagnosed hypertensive subjects. On the other hand, the regression tree showed a classification accuracy of about 75% using as variables the hypertension grades, the age and the antihypertensive treatment.Conclusions: The study confirmed the SV dependence on various risk factors like age, hypertension and smoking, highlighting a new link with dyslipidemia and new relations depending on the hypertensive grades. Finally, despite the good accuracy shown by the prediction tree model, further parameters are to be considered to improve the sensitivity of the prognostic indicator.


Nematology ◽  
2020 ◽  
pp. 1-13
Author(s):  
Marissônia de A. Noronha ◽  
Marcelo F. Fernandes ◽  
Maria de Fatima S. Muniz ◽  
Elvira Maria R. Pedrosa ◽  
Mayara C. Assunção ◽  
...  

Summary Meloidogyne spp. and Pratylenchus spp. are the most damaging plant-parasitic nematodes to sugarcane and the knowledge of soil characteristics that influence the occurrence of these pathogens can be useful in their management. With the objective to investigate the relationships between soil variables and populations of Meloidogyne spp. and Pratylenchus spp. in sugarcane fields, root-zone soil and root samples were collected from 20 farms located in 16 municipalities in Alagoas state, Brazil. The multivariate regression tree technique was used to model the population density’s response variables for Meloidogyne spp. and Pratylenchus spp. in the root-zone soil and the roots according to sugarcane cultivars, soil organic matter, and soil chemical and physical variables. The results showed the existence of associations between soil factors, sugarcane cultivars and populations of nematodes. Root samples from soils with K > 37.79 mmolc dm−3, Al < 5.93 mmolc dm−3 and sugarcane ‘RB92579’, ‘SP753046’, ‘SP813250’ and ‘SP921631’ showed the lowest Pratylenchus spp. population densities. However, the lowest densities in the root-zone were found in soils with sum of bases > 1.91 mmolc dm−3, Ca:Mg ratio < 1:2 and soil organic matter < 10.7 g dm−3. The lowest population densities of Meloidogyne spp. in roots were associated with sugarcane ‘RB92579’, ‘RB93509’, ‘RB98710’, ‘SP791011’ and ‘SP921631’ and soil aggregate mean diam. > 0.48 mm, while root-zone densities were minimum in soils with P > 28.59 mg dm−3. This information should support further studies to investigate the effect of each variable on populations of Pratylenchus and Meloidogyne.


2020 ◽  
Vol 45 (6) ◽  
pp. 900-915
Author(s):  
Eleni Manou ◽  
Elias Thodis ◽  
Georgios Arsos ◽  
Ploumis Pasadakis ◽  
Stylianos Panagoutsos ◽  
...  

<b><i>Background:</i></b> Fibroblast growth factor 23 (FGF-23) and α-Klotho protein appear to have an important role in the pathogenesis of CKD-mineral and bone disorders. The aim of this study was to investigate the association of FGF-23 and α-Klotho levels with adverse clinical outcomes in patients with non-dialysis CKD. <b><i>Materials and Methods:</i></b> We conducted a prospective cohort study, enrolling participants with non-dialysis CKD from a single center in Greece. At enrollment, glomerular filtration rate (GFR) was measured (mGFR) and plasma levels of carboxyl terminal FGF-23 (cFGF-23) and soluble α-Klotho (sKlotho) were determined by enzyme-linked immunoassay. Participants were followed for up to 5 years or until the occurrence of the primary endpoint of initiation of renal replacement therapy or death. Multivariate regression tree analysis was used to identify informative baseline parameters in order to categorize participants. Also, using median values of cFGF-23 and sKlotho, participants were categorized into 4 groups, in whom survival was compared using Kaplan-Meier and Cox regression analysis. <b><i>Results:</i></b> 128 participants were enrolled with a median mGFR of 41.5 mL/min/1.73 m<sup>2</sup> (IQR = 28.2). Baseline mGFR correlated with cFGF-23 and sKlotho (<i>r</i> = −0.54 and <i>r</i> = 0.49, respectively; <i>p</i> &#x3c; 0.0001 for both). cFGF-23 and sKlotho levels correlated negatively (<i>r</i> = −0.24, <i>p</i> = 0.006). Multivariate regression tree analysis resulted in 3 groups defined by cutoff values of mGFR (60.9 mL/min/1.73 m<sup>2</sup>) and phosphate (3.7 mg/dL). These groups correlated with CKD stage, cFGF-23, and sKlotho (<i>p</i> &#x3c; 0.0001 for all). During a median follow-up of 36 months (IQR = 22), 40 (31.2%) participants reached the primary endpoint (31 initiated renal replacement therapy, 9 died). Survival to primary endpoint differed among the 4 groups formed using median values of both biomarkers, with the low FGF-23/high Klotho and high FGF-23/low Klotho having the longest and shortest survival, respectively. High FGF-23/low Klotho group, compared to the opposite one, had a significantly elevated risk of the primary outcome (HR, 6.8; 95% CI, 2.3–19.6; <i>p</i> = 0.0004). <b><i>Conclusions:</i></b> In patients with CKD stages 1–5, the combination of higher cFGF-23 and lower sKlotho levels along with mGFR and serum phosphate was associated with adverse clinical outcomes. The utility of combinations of traditional and novel biomarkers to predict outcomes warrants further study.


Author(s):  
Qindi ZHANG ◽  
Zongshan LI ◽  
Lei YANG ◽  
Xing WU ◽  
Jintun ZHANG

ABSTRACTPangquangou National Nature Reserve is well known as ‘the distribution centre of Prince Rupprecht's larch (Larix principis-rupprechtii)' in China. Community variation in Prince Rupprecht's larch forest provides habitat heterogeneity for animals, especially for the endemic and endangered brown-eared pheasant (Crossoptlon mantchuricum). In this study a total of 120 quadrats (each 10×10m) were established to measure and record species composition and six environmental variables to examine the underlying variables that control community variation. We applied a multivariate regression tree analysis to detect community variation, and used redundancy analysis-based variation partitioning to separate the effects of environmental variables on community variation. The results show that Prince Rupprecht's larch forest in the Pangquangou National Nature Reserve can be represented by eight community types. The amount of total species variability captured by all environmental variables was 20.6%, and the cumulative percentage variance of species–environment relationships was 95.8%. However, analyses with a conditional effect approach revealed that elevation, aspect and litter thickness contribute the most to community variation. The pure and joint effects of these three explanatory variables were separated with variation partitioning analyses. The results highlight that the effect of elevation accounts for the largest fraction of community variation in Prince Rupprecht's larch forest.


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