Search results for "GRADE"
showing 10 items of 695 documents
Actively Q-switched DFB fiber laser for Brillouin sensor applications
2009
Q-switching of distributed feedback (DFB) fiber lasers permits to achieve high peak powers, preserving an ultra narrow linewidth [1,2]. The development of a new in-line acousto-optic modulator based on a magnetostrictive actuator, instead of a piezoelectric-based device, permits an efficient excitation of elastic pulses propagating along the optical fiber and an easy access to both emission outputs of the laser. The repetition rate can be continuously adjusted, as well as the amplitude of the elastic pulses. The interaction of these elastic pulses with a fiber Bragg grating written in an erbium-doped fiber permits an actively Q-switched operation of the DFB fiber laser [3]. The birefringenc…
Single- to three-wavelength switchable ytterbium-doped fiber laser based on intracavity induced loss by a long-period holey fiber grating
2011
In this paper, we propose and demonstrate a versatile and simple single-, dual- and three-wavelength switchable ytterbium-doped fiber laser using the intracavity induced-loss generated by a mechanically induced long-period grating (MLPFG) in a holey fiber. The laser net gain in the cavity is reshaped through the MLPFG by adjusting the twist rate and the pressure of the holey fiber in the long-period grating. In this way, the twist response of the MLPFG enables the laser to switch between the single-, dual-, and three-wavelength operations and the tuning of the simultaneous two- and three-wavelengths. These results are of great interest in the design of flexible multiwavelength sources with …
Tevatron Run II combination of the effective leptonic electroweak mixing angle
2018
The Ministry of Science and Innovation and the Consolider-Ingenio 2010 Program and the European Union community Marie Curie Fellowship Contract No. 302103.
Sealing ability of five different retrograde filling materials.
1996
The sealing ability of Amalgam, Harvard-Cement, Diaket, gold-leaf, and Ketac-Endo as retrofilling materials was investigated. Paper cones were fixed with Harvard-Cement in the instrumented roots of 100 extracted human incisors. Apicectomy was performed and a 2-mm-deep retrograde cavity was prepared. Teeth were assigned to five groups (n = 20); each group received a different filling material. Surfaces of the roots were isolated with nail polish. Teeth, were stored in 1% methylene blue dye for 72 h. Roots were sectioned, and the depth of dye penetration was evaluated through a stereomicroscope. Retrofills with Ketac-Endo showed significantly less leakage compared with amalgam. There was no s…
La lecture au CP : les déterminants de la réussite
2003
Actes du colloque de l'Apfée, Conseil Régional Rhône-Alpes, 19 octobre 2002; Il s'agit d'une synthèse (plus sélective qu'exhaustive) des résultats de recherches empiriques françaises portant sur le fonctionnement du CP, articulée selon le plan suivant : dans un premier temps, l'auteur centre son propos sur la diversitié des acquisitions des élèves à l'entrée au CP et il identifie les facteurs qui sont à l'origine de cette diversité ; dans un second temps, il s'intéresse à l'évolution des écarts entre élèves pendant l'année de CP, et plus particulièrement des écarts sociaux ; un troisième point est consacré à l'influence des variables scolaires et pédagogiques sur les progressions des élèves.
The role of individual processes and learning environment in the prediction of grades in a sample of Norwegian students
2018
Student grades are traditionally used to evaluate academic achievement in higher education. A review of previous research indicates a relatively clear tendency to adopt either an individual or contextual approach in exploring this subject. The present study represents an attempt to simultaneously examine effects of individual variables and learning environment on academic achievements as measured in grades. The study adopts a quantitative approach and reports data collected from students enrolled in early childhood education in a mid-sized university in Norway. Results of a stepwise hierarchical regression demonstrate that individual variables (e.g. nonmandatory school attendance, self-effi…
Tardigrades of Finland: new records and an annotated checklist
2020
Species checklists are powerful and important tools of communication between taxonomists and applied environmental biologists, which in turn lead to well-planned and successful conservation strategies and ecological studies. Despite this, only recently the interest on compiling systematic checklists is growing among taxonomists who study tardigrades—micrometazoans that inhabit almost every habitat worldwide. As the Finnish records of tardigrades (a.k.a. water bears) species are incomplete, outdated and no checklist has ever been compiled for this country, an easy-to-consult checklist is here reported. This checklist covers all Finnish tardigrade taxa identified in the past and in the 13 sam…
School grading and institutional contexts
2011
We study how the relationship between students' cognitive ability and their school grades depends on institutional contexts. In a simple abstract model, we show that unless competence standards are set at above-school level or the variation of competence across schools is low, students' competence valuation will be heterogeneous, with weaker schools inflating grades or flattening their dependence on competence, therefore reducing the information content and comparability of school grades. Using data from the OECD-PISA 2003 Survey, the model is applied to a sample of four countries, namely Australia, Germany, Italy, and the Netherlands. We find that in Australia, schools' heterogeneity does …
Same work, lower grade? Student ethnicity and teachers’ subjective assessments
2010
Previous research shows that ethnic minority students perform poorer in school when they are taught by ethnic majority teachers. Why this is the case was unclear. This paper focuses on one important potential explanation: I examine whether ethnic majority teachers grade minority and majority students differently for the same work. Using an experiment, I rule out the existence of such a direct grading bias. I do find indirect evidence for alternative explanations: teachers report lower expectations and unfavorable attitudes that both likely affect their behavior towards minority students, potentially inducing them to perform below their ability level. Effects of having majority teachers on m…
The Simpson paradox of school grading in Italy
2009
Abstract Data from the 2003 OECD-PISA Survey for Italy reveal a striking difference in the relationship between students’ competence (as measured by PISA score in Mathematics) and school grades across regions: a competence level granting bare sufficiency in the North yields excellence grades in the South. This has spurred a lively debate on education policy in the country, based on the inference drawn from this evidence that grading practices are excessively different in the two areas. We show in this note that this inference overlooks a Simpson paradox hidden in the data. After a more careful analysis, the above inference is seen to be wrong. The crucial omitted variable is the school-leve…