0000000000111631
AUTHOR
Federico Torretta
Growth curves of sorghum roots via quantile regression with P-splines
Plant roots are a major pool of total carbon in the planet and their dynamics are directly relevant to greenhouse gas balance. Composted wastes are increasingly used in agriculture for environmental and economic reasons and their role as a substitute for traditional fertilizers needs to be tested on all plant components. Here we propose a regression quantile approach based on P-splines to assess, quantify and compare the root growth patterns in two treatment groups respectively undergoing compost and traditional fertilization.
Does Exist A Correlation Between BMI and Gleason Patterns 4 and 5 At Prostate Biopsy?
Background: Obesity has been related with higher Gleason grade and worse prognosis. Increasing proportion of Gleason pattern 4 or 5 is a critical factor for biochemical recurrence, progression and mortality. The endocrine activity of visceral fat could be responsible of the differentation of the prostatic malignant cell towards a more aggressive fenotype. The aim of our study was to correlate Body Mass Index with the presence of Gleason pattern 4 or higher at biopsy. Materials and Methods: Consecutive patients with positive prostate biopsy were included. A transrectal prostate biopsy procedure with 12 cores, was performed. All tissue samples were reviewed. Results: Out of 135 patients diagn…
Smoking, diabetes, blood hypertension: possible etiologic role for Peyronie’s disease? Analysis in 279 patients with a control group in Sicily
Objective: To assess the proportion of patients with Peyronie’s Disease (PD) and the possible association with its potential risk factors in the general population of the central and western Sicily in our weekly andrological outpatient clinic. Materials and methods: We recruited a sample of 279 consecutive patients consulting our andrological outpatient clinic. Two arms were created: the first one composed by PD patients (men with symptoms suggestive for PD), the second one composed by patients with other andrological diseases (control arm). For each patient we evaluated the age, cigarette smoking, diabetes, blood hypertension and erectile function. In the PD arm we administered validated q…
Penn classification in acute aortic dissection patients
Objective The objective of this study was to evaluate the effectiveness of the Penn classification in predicting in-hospital mortality after surgery in acute type A aortic dissection patients. Methods We evaluated 58 patients (42 men and 16 women; mean age 62.17 ± 10.6 years) who underwent emergency surgery for acute type A aortic dissection between September 2003 and June 2010 in our department. We investigated the correlation between the pre-operative malperfusion and in-hospital outcome after surgery. Results Twenty-eight patients (48%) were Penn class Aa (absence of branch vessel malperfusion or circulatory collapse), 11 (19%) were Penn class Ab (branch vessel malperfusion with ischaemi…
Multiple smoothing parameters selection in additive regression quantiles
We propose an iterative algorithm to select the smoothing parameters in additive quantile regression, wherein the functional forms of the covariate effects are unspecified and expressed via B-spline bases with difference penalties on the spline coefficients. The proposed algorithm relies on viewing the penalized coefficients as random effects from the symmetric Laplace distribution, and it turns out to be very efficient and particularly attractive with multiple smooth terms. Through simulations we compare our proposal with some alternative approaches, including the traditional ones based on minimization of the Schwarz Information Criterion. A real-data analysis is presented to illustrate t…