Search results for "Positive correlation"

The Choice of Item Difficulty in Self-Adapted Testing

2000

Summary: The difficulty level choices made by examinees during a self-adapted test were studied. A positive correlation between estimate ability and difficulty choice was found. The mean difficulty level selected by the examinees increased nonlinearly as the testing session progressed. Regression analyses showed that the best predictors of difficulty choice were examinee ability, difficulty of the previous item, and score on the previous item. Four strategies for selecting difficulty levels were examined, and examinees were classified into subgroups based on the best-fitting strategy. The subgroups differed with regard to ability, pretest anxiety, number of items passed, and mean difficult…

What Do Secondary Students Really Learn during Investigations with Living Animals? Parameters for Effective Learning with Social Insects

2016

ABSTRACTExemplary for social insects, Temnothorax ants allow for various hands-on investigations in biology classes. The aim of this study was to provide a quantitative and qualitative analysis of secondary school students’ learning achievement after teaching units with ants lasting between one and six weeks. The questionnaires included transfer and factual knowledge tasks divided into eight fields of knowledge. Students (N  =  459) from 22 classes participated in the study and received different treatments: The experimental group (n  =  366) started their investigations by initial observation using stereo microscopes, while the control group (n  =  93) conducted ant research without this i…

Multiple Motivations Consequences on Bidder's Optimal Strategy in Takeover Contests

2011

This paper examines the optimal bidding strategy in takeover contests for a target firm, and the positive correlation between the bidders’ valuation. We consider risk neutral bidders who compete for the control of a target firm in which they get initial shareholdings. The bidder valuation for target firm is correlated with his motivations which determine the bidder’s strategy. We study bidder’s optimal strategy in mixed motivations setting. Since motivations are numerous, hypothesis of affiliated value in auctions allows to study bidder’s strategy. The paper shows that the impact of affiliation degree on bidder’s optimal strategy depends on their private signal and on the ratio between thei…

Tomografía computarizada a nivel de C3 y dinamometría como técnicas de diagnóstico de sarcopenia en pacientes con cáncer de cabeza y cuello

2020

Introducción: Estudio piloto que determina el diagnóstico de sarcopenia mediante tomografía computarizada (TC) a nivel de la tercera vértebra cervical (C3) y dinamometría en pacientes con cáncer de cabeza y cuello. Comparación de la masa magra (MM) determinada mediante TC con técnicas clásicas de antropometría y dinamometría.Material y métodos: Se analizó la MM y el tejido adiposo mediante TC a nivel de C3 en 37 pacientes oncológicos mediante Unidades Hounsfield (UH). Posteriormente, se calculó el índice musculoesquelético (IME) y se determinó la fuerza prensora de mano para la determinación de sarcopenia. Por último, se comparó el IME mediante técnicas de valoración antropométrica clásica …

Investigations on the phosphoenolpyruvate carboxylase activity of spruce needles relative to the occurrence of novel forest decline

1991

Summary Investigations were carried out on phosphoenolpyruvate carboxylase (PEPC) activity in needles of Norway spruce trees [ Picea abies (L.) Karst.] at two natural sites during the course of three vegetation periods. PEPC activity found in needles of damaged trees was considerably higher than in needles of undamaged trees. Annual average figures varied up to 100%. The positive correlation between PEPC activity and the extent of damage of the investigated needles indicates a significant relationship between both parameters: the PEPC activity in spruce needles seems to be not only a qualitative, but also a quantitative indicator of the extent of damage. Higher PEPC activity in needles of d…

Is Khat (Catha edulis) chewing a risk factor for periodontal diseases? : a systematic review

2017

Background Khat (Catha edulis) chewing is a highly prevalent habit in the Arabian Peninsula and East Africa, and has recently spread to Western countries. The association between khat chewing and oral mucosal lesions is well documented in the literature. However, there is no concrete evidence on the association between khat chewing and periodontal disease. The purpose of this systematic review was to analyze the influence of khat chewing on periodontal health. Material and methods A literature search of PubMed, Scopus and Web of Sciences databases was carried out to identify relevant articles published from 1990 to May 2017. The inclusion criteria were all clinical studies that assessed the…

The bleaching efficacy of carbamide peroxide gels containing potassium nitrate desensitizer

2020

Background To evaluate the bleaching efficacy of at-home carbamide peroxide (CP) gels in two concentrations, containing or not a desensitizing agent. Material and methods Forty incisors were divided into four groups (n=10), according to gel concentrations (10% or 22%), and presence or not of 3% potassium nitrate in the gel. A thin layer of gel was applied to the buccal surface of each tooth for 2h/day for 4 weeks. Bleaching efficacy was measured using a spectrophotometer, and ∆E*ab, ∆E00 and ∆WID were calculated. Measurements were performed at baseline, 7, 14, 21, 28, and 35 days following the first gel application. Data were analyzed by two-way RM-ANOVA and Tukey's test (α=0.05). Results R…

Administrative legitimacy and the democratic deficit of the European Union

2017

This article suggests a new concept of measurement for the EU’s oft-alleged democratic deficit based on two contributions. First, we turn attention to the administrative staff involved in policy-making rather than the (un)accountability of EUs’ parliamentarians and executive agents. Second, building on the idea that policy-makers’ legitimacy depends on the extent to which they can claim to represent some groups or social interests, we assess the extent to which Commission officials’ preferences reflect European citizens’ policy stance. Our results indicate a statistically significant positive correlation between the policy preferences of EU administrative staff and their home country popula…

2019

Background: Cranio-facial anomalies frequently occur in neurodevelopmental disorders because both face and brain are derived from neuroectoderm. The identification of differences in the facial phenotype of children with Autism Spectrum Disorders (ASD) may reflect alterations in embryologic brain development in children with ASD. Methods: we evaluated 33 caucasian children with ASD using a 2D computerized photogrammetry. Anthropometric euclidean measurements and landmarks located on the soft tissue of the face and head, were based on five cranio-facial indexes. Relationships between anthropometric z-scores and participant characteristics (i.e., age, Global IQ, severity of autistic symptoms m…

The stability of color discrimination threshold determined using pseudoisochromatic test plates

2014

Congenital red-green color vision deficiency is one of the most common genetic disorders. A previously printed set of pseudoisochromatic plates (KAMS test, 2012) was created for individual discrimination threshold determination in case of mild congenital red-green color vision deficiency using neutral colors (colors confused with gray). The diagnostics of color blind subjects was performed with Richmond HRR (4th edition, 2002) test, Oculus HMC anomaloscope, and further the examination was made using the KAMS test. 4 male subjects aged 20 to 24 years old participated in the study: all of them were diagnosed with deuteranomalia. Due to the design of the plates, the threshold of every subject …