Search results for "Statistical analysis"

Undergraduate Students’ Acceptance of a Reciprocating One-File System for Endodontic Treatment

2020

Abstract Objectives Reciprocating endodontic one-file systems are a comparatively new method for root canal shaping. Even though the mechanical properties are comparable to modern rotating mechanical systems, data about subjective assessment and application quality are scarce. This study evaluates the reciprocating one-file system in undergraduate education. Materials and Methods A total of 42 undergraduate students without experience regarding reciprocating file systems filled in a questionnaire in four different points in time (t 1–t 4) anonymously. The questionnaire was based on a numerical rating scale ranging from 0 to 10. Statistical Analysis A least significant difference post-hoc an…

Statistical analyses on the essential oil of italian coriander (coriandrum sativum L.) fruits of different ages and origins

2002

Thirty-one samples of Coriandrum sativum L. fruits, of different origin, year of cultivation (harvest) and crop management systems were subjected to volatile component analysis by combining Head Space Solid Phase Microextraction (HS-SPME) with GC/MS. In order to determine the importance of the major sources of volatile variability, some statistical analyses, including Cluster Analysis (CA) and Principal Component Analysis (PCA), were performed on the obtained data. The compounds, which gave the main contribution to the partition and classification of the original data, were α-pinene, p-cymene, γ-terpinene and linalool. The age of the fruits, which ranged from 1–16 years, seemed to generate …

The pentafluorophenyl group as π-acceptor for anions: a case study

2015

Chemical science 6(1), 354-359 (2015). doi:10.1039/C4SC02762K

Corrigendum: ExGUtils: A Python Package for Statistical Analysis With the ex-Gaussian Probability Density

2018

SPSS: Análisis de distractores

2014

Mostra com fer l'analisi de distractors d'una prova. Realizar el análisis de distractores de una prueba estandarizada. It shows how to realise the distractor analysis of a standarized test.

SPSS: Importar desde hoja de cálculo

2014

S'ilustra la forma d'importar dades des de una fulla de càlcul a SPSS Se indica la forma de importar datos a SPSS desde una hoja de cálculo It is described the way for import data from an Excell Sheet

Temporal trends of heavy metals in sediment core from the gulf of Palermo (Sicily, Italy)

2009

The evaluation of long–term heavy metal concentrations in the Gulf of Palermo was carried out in this study. Measurements of Cr, Cu, Hg, Pb and Zn concentrations were performed by atomic absorption spectrophotometry (AAS) on dated fractions of a sediment core, dated by the 210Pbex method. They are found to cover a time period from 1951 to 2004. The constant sedimentation rate model was used for dating. Specific activities of 137Cs have also been measured in the sediment core sections as a check of the time scale derived by the 210Pbex method. A time-series analysis based on temporal decomposition was used in order to investigate the presence of heavy metal pollution trend. The additive comp…

Tooth replacement rates in early chondrichthyans: a qualitative approach

2009

The continuous replacement of teeth throughout their lifetime is a common characteristic of most chondrichthyans. This process was already present in the earliest representatives of the group. It has been well established that different species of extant sharks show rapid tooth replacement rates; however, some authors have suggested that in early chondrichthyans this rate might have been much slower. Here we present a qualitative approach to analyse tooth replacement rates in the Early Devonian shark Leonodus carlsi, the earliest tooth-bearing shark known to date. For this, we have examined 1,103 isolated teeth from Celtiberia, Spain. Our study provides strong evidences of an extremely slow…

Evaluation of alveolar cortical bone thickness and density for orthodontic mini-implant placement.

2013

Objective: Mini-implant stability is primarily related to bone quality and quantity. This study evaluated alveolar cortical bone thickness and density differences between interradicular sites at different levels from the alveolar crest, and assessed the differences between adolescents (12-18 years of age) and adults (19-50 years of age), males and females, upper and lower arch, anterior and posterior region of jaws and buccal and oral side. Study Design: In this retrospective study, 48 Computed Tomography scans, performed for oral surgery purposes were selected from dental records of 3,223 Caucasian orthodontic patients. The SimPlant software (Materialise, Leuven, Belgium) was used to measu…

Study of quantitative and qualitative variations in essential oils of Sicilian oregano biotypes

2015

Essential oil (EO) was extracted using hydrodistillation from samples of Origanum vulgare subspecies hirtum (Link) Ietswaart, gathered from the wild in various parts of Sicily, Italy; GC-FID and GC-MS analyses were subsequently performed. The aim of the study was to analyze the relationship between essential oil yields and the geographical distribution of oregano wild populations based on variations in environmental factors as collection sites. Moreover, the purpose was to group Origanum vulgare subspecies hirtum biotypes according to the chemical composition of the EO. The seven principal components in the EO was thymol (24.0–54.4%), γ-terpinene (9.8–30.5%), ρ-cymene (5.2–18.7%), α-terpine…