• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1270
  • 916
  • 330
  • 324
  • 144
  • 52
  • 43
  • 35
  • 27
  • 27
  • 27
  • 27
  • 27
  • 26
  • 25
  • Tagged with
  • 3809
  • 720
  • 402
  • 319
  • 247
  • 239
  • 238
  • 234
  • 202
  • 192
  • 162
  • 160
  • 145
  • 136
  • 135
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
271

Functions of bounded variation

Lind, Martin January 2006 (has links)
The paper begins with a short survey of monotone functions. The functions of bounded variation are introduced and some basic properties of these functions are given. Finally the jump function of a function of bounded variation is defined.
272

Defining a non-complex learning object from preschool to upper secondary school

Olteanu, Constanta, Holmqvist, Mona January 2010 (has links)
The aim of this article is to analyse the aspects that teachers intend to focus on in teaching mathematics and the students' needs, i.e. what is critical for student learning. The article develops an argument for the importance of identifying the “critical aspects” as a basis for the teachers to promote student learning of Mathematics from preschool to upper secondary school. The article concludes that what teachers believe that students need to be offered concerning a specific content of Mathematics does not correspond to students' needs. Gaps between the intended and the enacted object of learning show that both the way the object of learning is offered and the way this is communicated in a teaching situation could be improved.
273

The impact of genetic variation in ABCA1 on cholesterol metabolism, atherosclerosis and diabetes

Brunham, Liam Robert 05 1900 (has links)
The ATP-binding cassette transporter, sub-family A, member 1 (ABCA1) mediates the major pathway for cholesterol exit from non-hepatic cells and thereby controls the rate-limiting step in the biogenesis of high density lipoprotein (HDL) particles. In humans,ABCA1 deficiency results in Tangier disease, characterized by low levels of HDL cholesterol, cellular cholesterol accumulation and increased risk for atherosclerosis. More than 100 coding variants have been described in the ABCA1 gene. We attempted to understand how both naturally occurring and engineered mutations in ABCA1 impact its role in cholesterol transport in a variety of in vitro and in vivo systems. We attempted to correlate specific genetic variants in ABCA 1 with phenotypes in patients carrying the sevariants, and used an evolutionary approach to predict which specific variants in ABCA1would impact its function. We then turned to the study of tissue-specific genetic deletion of ABCA1 in mice to study its role in HDL biogenesis, atherosclerosis and glucose metabolism. We found that intestinal ABCA1 is an important site of HDL biogenesis and that activation of intestinal ABCA1 raises HDL levels in vivo. Hepatic ABCA1, which is a major site of HDL biogenesis, was shown to significantly contribute to susceptibility to atherosclerosis. Finally, we show that ABCA1 plays an unsuspected role in B-cell function and insulin secretion. These studies have contributed to our understanding of the impact of genetic variation in ABCA1 on diverse biological and pathological processes, and have identified novel aspects of ABCA 1 function in specific cell types.
274

Avfallshantering med Silly och Roger : Ett undervisningsmaterial i teknik för förskoleklass till årskurs tre

Forsell, Linda January 2013 (has links)
Syftet med detta utvecklingsarbete var att skapa ett undervisningsmaterial som genom ett varierat arbetssätt och med ett helhetsperspektiv på avfallshantering som system ge elever möjlighet att utveckla ett intresse och få en förståelse för avfallshanteringens process och avfallshantering i sin närmiljö. Undervisningsmaterialet består av en lärarhandledning och en arbetsbok som riktar sig till elever och lärare i förskoleklass till årskurs 3. Arbetsboken är uppbyggd i sex avsnitt där varje avsnitt innehåller en sagodel, en diskussionsdel, undersöka och laborationsdel, en faktadel, en pysseldel. I lärarhandledningen beskrevs det hur lärare kan arbeta med arbetsboken. Undervisningsmaterialet utvärderades av tre lärare och en förskollärare. Från utvärderingen av lärare i skolan skrevs det ”Man blev sugen att starta upp ett arbete kring avfallshantering direkt när man läste igenom arbetsboken och lärarhandledningen”. Den övergripande bilden av utvärderingen var positiv. Utifrån utvärderingen framkom det att samtliga deltagare ansåg att undervisningsmaterialet var lättillgängligt för lärare med ett varierat upplägg och att det gav elever möjlighet till intressekapande och kunskapande om avfallshantering i närmiljön.
275

Large-scale nutrient pattern in the Gulf of Bothnia with the hydrodynamic of its loads

Salawu, Lukman January 2006 (has links)
Eutrophication, which is the most important degradation in water bodies, has been traced to the imposed loading of nutrients. Of interest is the fact that the process is often accompanied with undesirable effects, one of which is primarily the increased algae production at the surface and accumulation of biomass at the bottom and the secondary responses, which include a., change in species composition b. change in the biogeochemical cycle c. shift in the seasonal pattern and magnitude variability. The biogeochemical cycle in response to hydrodynamic alterations may occur internally; however external loading often fosters the process over large spatial scales. In the quest of validating the above statement, we hypothesized that there is no difference in the mean concentration of nutrients in the Gulf of Bothnia from the overall mean concentration. The analysis was done with a probability mapping method, in which all stations were grouped into a lattice. The cells are constructed using a grid system, i.e. x and y axis (longitude and latitude). Basically the method statistically tested for variables deviating from the over mean concentration. The variables analyzed are DIN, DSi, DIP and DIN: DSi. Results of the analysis showed significant spatial variations in the nutrient distribution in the Gulf of Bothnia; such differences were observed in the coastal to the deep zones of the Gulf.
276

Characterization of the Bovine Cathelicidin Gene Family

Flores, Erin Gillenwaters 2011 August 1900 (has links)
Cathelicidins (CATHLs) are small, cationic antimicrobial peptides that establish an early innate immune defense against infections in mammals. Beyond their wide spectrum of antimicrobial activity, these peptides play important roles in wound repair, chemotactic activity, and apoptosis. Thus, comprehensive characterizing of bovine CATHLs could potentially identify underlying inherited differences in innate immunity and disease resistance in cattle. The purpose of the present study was to verify the placement of the CATHL cluster at the distal end of bovine chromosome 22 (BTA22), identify any single nucleotide polymorphisms (SNPs) and insertion-deletion (indel) polymorphisms within the gene family, explore copy number variation, and investigate the functional impact any of these variants may have in overall bovine innate immunity. A framework radiation hybrid map was constructed with 7 markers screened against the bovine 12,000 rad whole genome RH (12K WG-RH) panel, which when compared to the current genome assembly (Btau_4.0) confirmed current gene order. Comparative sequence analysis for 10 domestic cattle breeds representing both Bos taurus taurus and Bos taurus indicus revealed 60 SNPs, 7 of which were nonsynonymous, and 5 indel mutations. Data from array comparative genomic hybridization (aCGH) between four Angus and four Nelore animals showed a 2-fold increase in copy number of the CATHL4 locus, which was verified by quantitative PCR (qPCR) of genomic DNA. Nelore animals showed an approximate 2-fold increase in the CATHL4 gene. Subsequently, the expression of CATHL4 in Nelore neutrophils exhibited a range of 2- to 5-fold increases in CATHL4 gene expression. Finally, a colorimetric bactericidal assay was performed on the neutrophils of the same Angus and Nelore animals previously genotyped for copy number variations (CNVs). After in vitro challenges to Staphylococcus aureus, Salmonella typhimurium, Mannheimia haemolytica, and Pasteurella multocida, the killing capacity of Nelore neutrophils was approximately 20 percent greater than Angus neutrophils for M. haemolytica and 10 percent greater for P. multocida. Characterization of this antimicrobial gene family is central to developing a firm understanding regarding the effects CATHL variation has with respect to bovine innate immunity.
277

Intercomparaison de trois modèles dynamiques canadiens de prévision numérique saisonnière du climat

Yazidi, Hatem January 2006 (has links) (PDF)
Le principal objectif de ce mémoire consiste en l'évaluation de trois modèles dynamiques canadiens de prévision numérique saisonnière du climat. Ayant conscience de l'influence de l'océan sur la qualité des prévisions numériques saisonnières nous vérifierons au cours de ce travail l'hypothèse de base suivante: la persistance de l'anomalie de la température de la surface de l'océan Pacifique (SSTA) communique à l'atmosphère un certain degré de prévisibilité. Afin de vérifier cette hypothèse un ensemble de vingt-six années de simulations effectuées par chacun des modèles a été étudié. Ensuite, pour tenter d'améliorer la qualité des prévisions saisonnières, nous avons calculé la moyenne d'ensemble des trois modèles. Nous appellerons désormais cette technique multimodèle. Pour estimer la réponse de chacun des modèles aux effets du forçage de l'océan nous avons commencé par séparer les années prévues en deux catégories: les années caractérisées par une forte SSTA (années EPSO) et celles caractérisées par une faible SSTA (années NEPSO). Ensuite, nous avons étudié la prévision des modèles des deux derniers mois de la saison. Ceci nous permet de distinguer l'influence des conditions aux limites. Nos résultats montrent que durant les saisons d'hiver et printemps boréales les trois modèles ainsi que le multimodèle semblent bien reproduire les patrons de la circulation dynamique au sein de l'atmosphère (GZ500). On peut également y voir un potentiel pour l'amélioration de la qualité des prévisions à longue échéance. En outre, nous avons remarqué que la région tropicale est généralement mieux prévue par les modèles que les extra-tropiques. Enfin, nous avons remarqué que les modèles présentent une habileté à prévoir les champs atmosphériques au-dessus de certaines régions du globe en dehors des tropiques. Parmi ces régions nous citons le Pacifique Nord/Amérique du Nord dans le cas de GZ500 et la route des dépressions du Pacifique « Storm Track » dans le cas des précipitations. Le « Storm Track » du Pacifique influence le climat de l'est de l'Asie ainsi que celui de l'Amérique du Nord. L'habileté de nos modèles à prévoir le « Storm Track » du Pacifique n'avait pas été observée dans des études précédentes. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Prévision numérique saisonnière moyenne d'ensemble.
278

Study of genetic diversity in Puccinellia nuttalliana based on agronomic/morphological traits and AFLP molecular markers

2013 April 1900 (has links)
Native prairie grasses of western Canada have the potential for development as turf and forage grass cultivars for semiarid environments. Nuttall’s salt-meadow, or alkali grass (Puccinellia nuttalliana (Shultes) Hitchc.), is a native grass species in North America well known for its salt tolerance. Little information is available about the genetic diversity of natural populations of this species. Understanding the genetic diversity of this species is a prerequisite for developing populations for forage or turf use in western Canada. The objectives of this study were to assess the variation in agronomic/morphological characters and AFLP markers of collections of Puccinellia and identify promising populations and genotypes for turf and forage utilization. A four replicate randomized complete block field nursery of twenty-four collections from western Canada was established in 2010. Plant height, tiller number, crown diameter, dry matter yield, seed yield, and leaf related characters were measured for each collection in the summers of 2011 and 2012. Considerable phenotypic variation was detected among and within the twenty-four populations. Promising populations and genotypes were identified with respect to their superior turf and forage related characteristics. The amplified fragment length polymorphism (AFLP) technique was used to assess the comparative genetic diversity of the collections. Five AFLP primer pairs were employed to screen 15 genotypes from each population, and 185 polymorphic AFLP bands were scored for each sample. Their frequencies of occurrence ranged from 0.02 to 0.99 with a mean of 0.61. The analysis of molecular variance revealed more than 96% of the total AFLP variation resided within populations. Populations were not highly differentiated with only 4% of the total AFLP variation residing among populations. A Mantel test revealed a significant but low correlation between genetic and geographic distances (r=0.293; P=0.024) and non-significant correlation between genetic and phenotypic distances (r=0.070; P=0.282). Implications for P. nuttalliana conservation, germplasm sampling, and cultivar development are discussed.
279

Är 15 kulor fler än 15 legobitar? : En studie om vilka strategier barn använder när de räknar och om variation av antal, material och gruppering har betydelse när barn ska bestämma antal.

Ohlsson, Ann-Charlotte, Larsson, Lisbeth, Elgenkrona, Monia January 2008 (has links)
Syftet med examensarbetet var att undersöka vilka strategier barn använde sig av när de räknade samt om variation av antal, föremål och gruppering påverkade deras val av strategier. Undersökningen gjordes genom strukturerade observationer då femton barn, födda 2002, på tre olika förskolor räknade föremål där antal, gruppering och material varierades. I vårt teoriavsnitt bearbetades Gelman och Gallistels fem räkneprinciper och Martons variationsteori. Resultatet visade att barn använde sig av samtliga fem räkneprinciper på olika sätt och i olika ordning när de räknade samt att både antal, material och gruppering hade betydelse för barns val av strategier vid antalsbestämning. Barnen hade lättare att räkna legobitar än kulor och behärskade de olika principerna bättre då antalet var färre eller materialet grupperat i rader.
280

Motivera och variera : Ett utvecklingsarbete med fokus på språkutveckling

Rydstedt, Sandra January 2011 (has links)
Det här utvecklingsarbetet har som syfte att ta fram språkutvecklande aktiviteter som motiverar och väcker elevernas nyfikenhet. Aktiviteterna är tänkta att tilltala flera sinnen. Jag har planerat fem aktiviteter som på olika sätt ska bidra till elevernas språkutveckling. Av dessa har jag genomfört tre och observerat två. Eleverna har bland annat tränat på att tala, lyssna, skriva och fantisera. I utvärderingen av aktiviteterna kunde jag se att eleverna tyckte de var roliga och att de var medvetna om vad de tränade. Så slutsatserna av utvecklingsarbetet är att det är bra att variera sin undervisning och plocka in aktiviteter som motiverar och lockarfram elevernas nyfikenhet för att få ett större engagemang från elevernas sida.

Page generated in 0.1128 seconds