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  • 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.
631

F-3-lärares motivationsarbete i matematikämnet : En kvalitativ studie som fokuserar på samspelet mellan elev, lärare och ämne

Avelin, Denise, Kvist, Ida January 2023 (has links)
Tidigare forskning visar att motivation påverkar elevers utveckling, resultat och prestationer i ämnet matematik. Syftet med denna kvalitativa studie är att undersöka om och hur F-3-lärare arbetar för att motivera alla elever i matematikämnet. Studiens teoretiska perspektiv är den didaktiska triangeln som synliggör relationen mellan lärare, elev och ämne. Den didaktiska triangeln blir relevant för studien då vi undersöker och analyserar hur lärare arbetar för att motivera sina elever i ämnet matematik. Studien har en kvalitativ datainsamlingsmetod där sex lärare intervjuades. Intervjuerna bearbetades och analyserades utifrån en tematisk analys. Det insamlade materialet ligger till grund för studiens resultat som besvarar de två forskningsfrågorna. Resultatet visar att lärare arbetar varierat, individanpassat och lustfyllt för att motivera alla elever. Vi kan då dra slutsatsen att dessa aspekter blir viktigt för att motivera elever i matematik och att det kan påverka elevers utveckling, prestationer och resultat. Av resultatet kan vi även dra slutsatsen att olika faktorer kan möjliggöra respektive hindra elevers motivation i matematik. Faktorerna handlar om lärares inställning och resurser som digitala verktyg, personal, material och lokaler.
632

Religionskunskap i lågstadiet : En kvalitativ studie om F-3 lärares resonemang om ämnet religionskunskap / Religious knowledge in primary school : A qualitative study of teachers' reasoning on religion as a school subject

Toivainen, Rebecca, Forsberg, Pontus January 2021 (has links)
Syftet med föreliggande studie är att fördjupa kunskapen om lärares åsikter och ställningstaganden till hur religionskunskapsundervisningen bedrivs inom skolans lägre årskurser. Ansatsen är kvalitativ och det teoretiska perspektivet är det socialpedagogiska perspektivet. Studiens slutsats är att lärare som har många års erfarenhet har ett visst missnöje över läroplanens struktur och över den begränsade tid som ägnas åt religionskunskapsundervisningen och avsaknaden av ordentligt material att använda sig av.
633

The effects of 3-mercaptopropionic acid on the cardiovascular system and the content of GABA in specific areas of the brain: further evidence for GABAergic involvement in central cardiovascular control

Alsip, Nancy L. January 1984 (has links)
This document only includes an excerpt of the corresponding thesis or dissertation. To request a digital scan of the full text, please contact the Ruth Lilly Medical Library's Interlibrary Loan Department (rlmlill@iu.edu). / A role has been proposed for the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) in central cardiovascular control. This proposa 1 was based on the cardiovascular effects of agents which block or mimic the action of GABA on the post-synaptic membrane. This dissertation reported the cardiovascular effects of 3-mercaptopropionic acid (3-MP), an agent which inhibits GABA biosynthesis in the pre-synaptic nerve terminal in anesthetized guinea pigs. 3-MP interrupts GABAergic transmission by decreasing the amount of GABA in the brain. The effect of 3-MP on mean arterial pressure, heart rate and barorflex-induced bradycardia was determined as well as the mechanism(s) involved in observed changes. The content of GABA in four regions of the brain (hypothalamus, medulla, cerebellum and occipital cortex) was determined at the end of each experiment. In anesthetized guinea pigs, 3-MP (195 mg/kg, i.p.) elicited a biphasic response (Type I) in the majority of animals. This response consisted of sympathetically-mediated hypertension and tachycardia superseded by vagally-mediated bradycardia. The other response (Type II) consisted of only the sympathetically-mediated effects. The Type II response was associated with animals in which the vagus nerves were functionally impaired. In all brain regions measured, the GABA levels of both Types I and II were significantly lower than those of control animals. The sympathetically-mediated effects of 3-MP were reversed by chlordiazepoxide, a GABA-facilitory agent. Therefore, the 3-MP-induced cardiovascular effects appeared to reflect GABAergic activity in the bra in which resulted from a reduction of GABA content. The two phases of the Type I response may have resulted from a reduction of GABA content in specific brain regions. A reduction in hypothalamic GABA levels appeared to be related to the sympathetic activation and a reduction in medullary GABA levels appeared to be related to the vagal activation. In unparalyzed animals, 3-MP elicited convulsive movements as well as the described effects on the cardiovascular system. The centrally acting anticonvulsant phenytoin stopped 3-MP-induced motor manifestations of seizure activity without altering either blood pressure or heart rate. Therefore, the cardiovascular effects of 3-MP appeared to occur independent of the convulsive effect of this agent. These results support the hypothesis of GABAergic involvement in the central control of autonomic outflow to the cardiovascular system. The inability of phenytoin to reverse the cardiovascular effects of 3-MP suggests that these effects were independent of 3-MP-induced seizures.
634

Performance Evaluation of Optimal Rate Allocation Models for Wireless Networks

Padilla, Ryan Michael 13 April 2012 (has links) (PDF)
Convex programming is used in wireless networks to optimize the sending or receiving rates of links or flows in a network. This kind of optimization problem is formulated into a rate allocation problem, where each node in the network will distributively solve the convex problem and all links or flows will converge to their optimal rate. The objective function and constraints of these problems are represented in a simplified model of contention, interference, and sending or receiving rates. The Partial Interference model is an optimal rate allocation model for use in wireless mesh networks that has been shown to be theoretically superior to other conceptual models. This paper compares the Partial Interference model to three other models of wireless networks using the ns-3 simulator to verify these claims. It discusses where the model works as expected, where the model fails to improve network utility, and the limitations inherent to its use.
635

Mälarängsskolan / School of Mälarängen

Hallberg, Alexander January 2018 (has links)
Mälarängsskolan är en F-6 skola för ca 400 elever som ligger beläget mitt emellan de tre stadsdelarna Fruängen, Bredäng och Mälarhöjden. Byggnadens form knäcker  på två punkter för att följa tomtgränsen mot norr och omfamna skolgården åt söder, detta gör att man får in mycket dagsljus i byggnaden. Gymnastiksalen är delvis nedsänkt i marken för att möjliggöra taket som skolgårdsyta åt barnen. Planerna är utformade efter konceptet; öppen - på glänt - stängd. Markplanen innehåller verksamheter som ateljé, matsal, musik-, bild-, och slöjdsalar. Här kan man anordna aktiviteter på kvällar, helger och utanför skoltid. Plan två är enbart hemvister åt årskurserna 1-6 och plan tre innehåller administration, skolsköterska och kuratormottagning. Skolan är helt konstruerad av träelement. Väggarna är bärande KL-skivor staplade på varandra och matsalens samt idrottshallens konstruktion utgår från limträelement  med stora spännvidder. Jag har valt att konstruera skolan helt i trä då det är ett framtida byggnadssätt, en koppling till omgivningen och framförallt för dess miljövänliga fördelar. / The school of Mälarängen is a school for 400 pupils from pre school to the 6th grade wich is located between the three areas of Fruängen, Bredäng and Mälarhöjden. The bulding form breaks in two places, creating an asymetric form that follows the property line in the north and embraces the school yard to the south. This gives the building alot of natural light. The sports center is partly sunken to the ground to enable the roof as a playground and basketball court. The building is programmed after the concept of: Open - ajar - closed. The ground plane consists of operations such as studios, dining room, music-, art- and craft halls. On this floor you can arrange activities after school time. The second floor is only classrooms for grades 1-6 and the third floor contains administration, counselor and the school nurse. The entire school is designed by wood structures. The walls are CLT-walls that are stacked on each other and the structure in the dining hall and the sports center consists of laminated timber beams. I have chosen wood because its a futuristic building technique, a wink to the surroundings and because its enviromental qualities.
636

Effet de l'irradiation gamma sur le poly(éthylène téréphtalate) d'usage alimentaire

St-Germain, François January 2001 (has links)
Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.
637

Effect of Carbohydrate-Protein Beverage on Glycogen Resynthesis and Muscle Damage Induced By Eccentric Resistance Exercise

Wojcik, Janet Regina 27 April 1998 (has links)
This study examined effects of carbohydrate (C), carbohydrate-protein (CP), or placebo (P) beverages following eccentric resistance exercise on muscle damage by serum creatine kinase (CK), muscle protein breakdown by urinary 3-methylhistidine (3MH), muscle soreness, isokinetic muscle strength, muscle glycogen resynthesis, and serum hormones. Untrained males (N=26) underwent a 9-day controlled meat-free diet and 24 hr urine collections. To reduce glycogen, subjects cycled for 40 min at 70% of VO<sub>2peak </sub>followed by 5 cycling sprints on day 4 evening. On day 5, fasted subjects performed 100 eccentric leg flexions at 120% of 1-RM and drank C (n=8, 1.25 g C/kg), CP (n=9, 0.875 g C/kg, 0.375 g protein/kg), or P (n=9) beverages immediate post-exercise (IPE) and 2 hr later. Muscle biopsies were taken IPE on day 5, and days 6 and 8 mornings. Blood was obtained days 4-10 fasted plus IPE, 3 hr, and 6 hr post-exercise on day 5. At 3 hr on day 5, insulin was higher for CP (24.6 ( 15.5 &amp;#181;IU/ml) and C (17.2 +/- 10.9 &amp;#181;IU/ml) than P (5.3 +/- 0.4 &amp;#181;IU/ml, p<.05). Glycogen was low on day 5, partially recovered on day 6, and normal by day 8 (p<.01) with no difference among groups. Isokinetic quadriceps peak torque at 60<sup>o</sup>/s decreased 24% on day 6 and remained depressed by 21% on d 8 (p<.01) for all groups. Soreness peaked on day 7 and CK on day 8 (p<.01) with no differences by group. CK increased (p<.01) over day 5 (delta CP 24.6 +/- 19.1, delta P 39.2 +/- 71.6, delta C 70.8 +/- 60.4 U/L) and was highest for C (p<.05). On day 5, CP had lowest 3MH (193.0 +/- 13.8 &amp;#181;mol/d) versus C (251.1 +/- 22.5 &amp;#181;mol/d, p<.05). Testosterone at 3 hr on day 5 was lower for C (4.2 +/- 0.3 ng/ml) and CP (4.3 +/- 0.3 ng/ml) versus P (5.1 +/- 0.2 ng/ml, p<.05). In summary, glycogen, muscle strength and soreness were unaffected by beverage. However, a CP beverage may be beneficial for reducing muscle damage and protein breakdown on the day of eccentric resistance exercise. / Ph. D.
638

Identification of platelet activating factor (PAF) receptor in equine spermatozoa and its role in motility, capacitation and the acrosome reaction

Odeh, Awatef 30 October 2002 (has links)
Platelet activating factor (PAF) is a unique signaling phospholipid that has many biologic properties in addition to platelet activation. PAF roles in reproduction involve ovulation, fertilization, embryo development, implantation and parturition. It may also serve as a biomarker for normal sperm function. The presence of PAF receptor on the spermatozoa of 10 stallions was investigated by immunofluorescence microscopy. Statistical analysis revealed that the fluorescence intensity, FI (Mean+/-SEM), in the post- acrosomal region (FI= 2.60+/-0.15) was significantly higher (P< 0.01) than that in any other region of stallion spermatozoa. The effect of synthetic PAF on stallion spermatozoal motility, capacitation, and the acrosome reaction (AR) were evaluated. Treatment of 10 stallion semen samples with 10 â 4 to 10 â 13 M PAF resulted in statistically significant differences in motility and capacitation (r2 = 0.81 and 0.83 respectively). The concentration of PAF, incubation time and their interaction were highly significant (P< 0.01) for their effect on motility. Concentrations of PAF ranging from 10-9 to10-11 M were able to induce capacitation. Following capacitation in vitro with PAF, and induction of the acrosomal reaction by progesterone, transmission electron microscopy (TEM) was conducted on the spermatozoa of 3 stallions, to detect the true AR. Differences in PAF concentrations were highly significant as indicated by R-square (for intact: 97.2, reacted: 89.8, and for vesiculated: 98.1). Treating spermatozoa from 3 stallions with the PAF antagonist FR-49175 inhibited calcium release and fluorescence intensity with a median inhibitory concentration (IC50) of 10-7.5 M (r2=0.82, P<0.01) and 10-8 M (r2=0.92, P<0.01) respectively, suggesting a receptor mediated process for the mechanism of action of PAF. Although the exact mechanisms of PAF action on equine spermatozoa remain unclear, it is widely reported that PAF acts by a receptor-mediated mechanism and that the PAF receptor is a member of the family of G-protein coupled receptors with phospholipase C as the effector. Since the limited success in equine ART (e.g. IVF) is in part due to lack of efficient treatment of stallion spermatozoa for capacitation, PAF may be useful to help capacitate stallion spermatozoa. Without proper capacitation, spermatozoa are unable to initiate the acrosome reaction which is a prerequisite for fertilization. / Ph. D.
639

Prediction of Building Count and Dimensions from U.S. Census Data Using Multiple Regression

Leach, Jamison Dane 19 October 2001 (has links)
Providers of high-speed, wireless data services need to know where in their service area to place transmitters to reach potential customers. Viewshed analysis, a technique found in Geographic Information Systems (GIS) software, can be used to model propagation of the wireless signals from different locations to find the best transmitter site. To carry out viewshed analysis, digital data are required for all obstructions the signal may encounter along its path. One such obstruction, terrain, can be represented in the GIS by easily available Digital Elevation Models (DEMs). Another obstruction is buildings, which are common in populated areas, and therefore of particular concern to wireless providers. Unfortunately, digital data for buildings in U.S. cities and towns are often non-existent, difficult to obtain, or very costly. In light of the difficulties surrounding acquisition of building data for wireless propagation studies, this study used Multiple Regression analysis to construct models to predict building count and dimensions. U.S. Census Housing and Demographic data, aggregated at the Census Block level, served as the predictor variables in the regression equations. The models were built from sample data collected from four U.S. cities. For each variable to be predicted (Y), the top models were compared to find the optimum one. The model chosen for Building Count (per Block) showed quite good results, and future research in the prediction of this variable shows promise. Results for the models of Average Building Height and Average Building Footprint Area (both per Block) were not nearly as encouraging, but additional work modeling these variables may still yield insights. / Master of Science
640

Simultaneous printing of tissue and customized bioreactor / Simultanes Drucken von Gewebe und angepasstem Bioreaktor

Gensler, Marius E. January 2023 (has links) (PDF)
Additive manufacturing processes such as 3D printing are booming in the industry due to their high degree of freedom in terms of geometric shapes and available materials. Focusing on patient-specific medicine, 3D printing has also proven useful in the Life Sciences, where it exploits the shape fidelity for individualized tissues in the field of bioprinting. In parallel, the current systems of bioreactor technology have adapted to the new manufacturing technology as well and 3D-printed bioreactors are increasingly being developed. For the first time, this work combines the manufacturing of the tissue and a tailored bioreactor, significantly streamlining the overall process and optimally merging the two processes. This way the production of the tissues can be individualized by customizing the reactor to the tissue and the patient-specific wound geometry. For this reason, a common basis and guideline for the cross-device and cross-material use of 3D printers was created initially. Their applicability was demonstrated by the iterative development of a perfusable bioreactor system, made from polydimethylsiloxane (PDMS) and a lignin-based filament, into which a biological tissue of flexible shape can be bioprinted. Cost-effective bioink-replacements and in silico computational fluid dynamics simulations were used for material sustainability and shape development. Also, nutrient distribution and shear stress could be predicted in this way pre-experimentally. As a proof of functionality and adaptability of the reactor, tissues made from a nanocellulose-based Cellink® Bioink, as well as an alginate-based ink mixed with Me-PMeOx100-b-PnPrOzi100-EIP (POx) (Alginate-POx bioink) were successfully cultured dynamically in the bioreactor together with C2C12 cell line. Tissue maturation was further demonstrated using hMSC which were successfully induced to adipocyte differentiation. For further standardization, a mobile electrical device for automated media exchange was developed, improving handling in the laboratory and thus reduces the probability of contamination. / Additive Fertigungsverfahren wie der 3D-Druck boomen in der Industrie aufgrund ihres hohen Freiheitsgrads in Bezug auf geometrische Formen und verfügbare Materialien. Mit Blick auf die patientenspezifische Medizin hat sich der 3D-Druck auch in den Biowissenschaften bewährt, wo er die Formtreue für individualisierte Gewebe im Bereich des Bioprinting nutzt. Parallel dazu haben sich auch die derzeitigen Systeme der Bioreaktortechnologie an die neue Fertigungstechnologie angepasst, und es werden zunehmend 3D-gedruckte Bioreaktoren entwickelt. In dieser Arbeit werden erstmals die Herstellung des Gewebes und ein maßgeschneiderter Bioreaktor kombiniert, wodurch der Gesamtprozess erheblich gestrafft und beide Verfahren optimal zusammengeführt werden. Auf diese Weise kann die Herstellung der Gewebe individualisiert werden, indem der Reaktor an das Gewebe und die patientenspezifische Wundgeometrie angepasst wird. Aus diesem Grund wurde zunächst eine gemeinsame Basis und Leitlinie für den Geräte- und Materialübergreifenden Einsatz von 3D-Druckern geschaffen. Deren Anwendbarkeit wurde durch die iterative Entwicklung eines perfundierbaren Bioreaktorsystems aus Polydimethylsiloxan (PDMS) und einem Lignin-basierten Filament demonstriert, in das ein biologisches Gewebe mit flexibler Form gedruckt werden kann. Kostengünstige Biotintenalternativen und emph in silico Computational Fluid Dynamics Simulationen wurden für eine materialschonende Formentwicklung verwendet. Nährstoffverteilung und Scherspannung konnten auf diese Weise präexperimentell vorhergesagt werden. Als Beweis für die Funktionalität und Anpassbarkeit des Reaktors wurden Gewebe aus einer Cellink® Bioink auf Nanocellulosebasis sowie einer Tinte auf Alginatbasis, welche mit Me-PMeOx100-b-PnPrOzi100-EIP (POx) gemischt wurde (Alginat-POx-Bioink), erfolgreich zusammen mit C2C12-Zelllinie dynamisch im Reaktor kultiviert. Die Gewebereifung wurde außerdem mit hMSC demonstriert, die erfolgreich zur adipozyten Differenzierung induziert wurden. Zur weiteren Standardisierung wurde ein mobiles elektrisches Gerät für den automatischen Medienwechsel entwickelt, welches die Handhabung im Labor verbessert und damit die Wahrscheinlichkeit einer Kontamination deutlich verringert.

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