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Visar resultat 1 - 5 av 399 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Mass Loss of Evolved Stars : Improving Mass-Loss Rates and Distances

   Författare :Miora Andriantsaralaza; Paul Barklem; Elvire De Beck; Susanne Höfner; Jacco van Loon; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; AGB stars; Mass loss; Distance; Circumstellar matter; Radio interferometry; Stellar evolution; Fysik med inriktning mot astrofysik; Physics with specialization in Astrophysics;

   Sammanfattning : In the final stages of their lives, low to intermediate-mass stars enter the Asymptotic Giant Branch (AGB) phase, where they experience significant mass loss through dusty stellar winds. This mass loss is pivotal, not only for the chemical enrichment of the interstellar medium, setting the stage for new stars and planets to form, but also in dictating the evolution and the ultimate fate of the stars themselves. LÄS MER

3. 2. Molecules and Dust around AGB stars : Mass-loss rates and molecular abundances

   Författare :Sofia Ramstedt; Hans Olofsson; Fredrik Schöier; José Cernicharo; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; AGB stars; mass-loss; circumstellar abundances; Formation and development of stars; Stjärnors bildning och utveckling; Astronomy; astronomi;

   Sammanfattning : All stars with a stellar mass of about 0.8–8 MSun will end their lives as asymptotic giant branch (AGB) stars. Through their extensive mass loss the AGB stars constitutes an important source of nuclear processed material. LÄS MER

4. 3. Dynamics of the Bacterial Genome : Rates and Mechanisms of Mutation

   Författare :Sanna Koskiniemi; Dan Andersson; Diarmaid Hughes; Ivan Matic; Uppsala universitet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; bacteria; bacterial evolution; genome reduction; gene loss; serial passage; DNA homology; tranlesion DNA polymerase; stress; Microbiology; Mikrobiologi; Bacteriology; Bakteriologi; Evolutionary Genetics; Evolutionär genetik; Mikrobiologi; Microbiology;

   Sammanfattning : Bacterial chromosomes are highly dynamic, continuously changing with respect to gene content and size via a number of processes, including deletions that result in gene loss. How deletions form and at what rates has been the focus of this thesis. In paper II we investigated how chromosomal location affects chromosomal deletion rates in S. LÄS MER

5. 4. Statistical Learning, Dynamics and Control : Fast Rates and Fundamental Limits for Square Loss

   Författare :Ingvar Ziemann; Henrik Sandberg; Raginsky Maxim; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Machine Learning; Control Theory; Statistical Learning; Fundamental Limits; Electrical Engineering; Elektro- och systemteknik;

   Sammanfattning : Learning algorithms play an ever increasing role in modern engineering solutions. However, despite many recent successes, their performance in the context of dynamical and control systems is not exactly well-understood. LÄS MER

7. 5. Ultralow-loss silicon nitride waveguides for nonlinear optics

   Författare :Zhichao Ye; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; ultralow loss; Kerr nonlinear optics; parametric amplifier; DKS microcombs; integrated waveguides; silicon nitride;

   Sammanfattning : The field of nonlinear optics relies on the interaction between high-intensity optical waves and nonlinear media. An integrated waveguide with large refractive index contrast allows to highly confine optical waves in a sub-μm^2 area, thus enhancing the optical intensity. LÄS MER