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Chemical abundances and kinematics of low-metallicity stars as tracers of early galactic formation, evolution and mergers
No full texttextIn studies of chemical abundances among a large sample of giant stars in
the similarly-aged globular clusters M4 and M5, I find that the clusters do not share
universal abundance patterns in spite of the similarity of their overall chemical enrichment
as described by their metallicity. M4 possesses overabundances of aluminum,
silicon, barium, lanthanum and europium, enhancements not accounted for
in the current theoretical understanding of stellar or globular cluster evolution but,
instead present clear evidence for differing nucleosynthetic histories between cluster
populations.
Abundance “families” also exist among halo field stars. Most exhibit very
similar abundance enhancements in α-elements such as magnesium, silicon, calcium,
and titanium with respect to iron and thus track the massive-star and supernovae
Type II nucleosynthesis yields that dominated the early Galactic halo ISM.
However, recent studies have identified stars with low-α abundances. I present
evidence of further chemical substructure within the low-α star population: some
low-α stars possess titanium and iron-peak overabundances of up to a factor of ten.
Understanding the nucleosynthetic origins of the overabundances does not lie in
current Galactic chemical evolution models. Ratios of supernovae II/Ia events I
have derived using chemical abundance patterns suggest that these stars may have
witnessed early Galactic supernovae Type Ia events. The results provide constraints
on current theories of supernovae Type Ia modeling and nucleosynthetic clues to
the progenitor masses and explosion parameters.
Also explored are the chemical abundances of stars which may have been
born outside the Galactic halo and are possibly the stellar debris of merger events.
The europium abundances and isotopic ratios I derive are consistent with those
found for the general halo population, supporting the idea of the “universality”
of the production process. However, I also find slight underabundances of the α-
elements which need to be confirmed with better data and better modeling. Underabundances
in the α-elements lend support to the idea that satellite systems,
which began with more limited supplies of star formation material, may have undergone
brief initial bursts of star formation followed by long periods of quiescent
stellar evolution before supernovae Type Ia’s began contributing to the interstellar
medium.Astronom
Urban environment of Madona county in author photography.
No full textMultimediju komunikācijaInformācijas un komunikācijas zinātnesMultimedia CommunicationInformation and Communication SciencesANOTĀCIJA
Bakalaura darbs “Madonas novada urbānās vides atainojums autorfotogrāfijā” ir izstrādāts, balstoties uz autorfotogrāfijām, kurās attēlots autores, novada iedzīvotājas, subjektīvs redzējums uz Madonas novada urbāno vidi.
Ir svarīgi izpētīt savu apkārtni un iepazīt to no dažādiem rakursiem. Novadam attīstoties un arvien paplašinoties urbanizācijas procesam, fotogrāfijas būs kā vēstures liecības par šo laiku.
Bakalaura darbs sastāv no teorētiskās daļas un radošās koncepcijas daļas. Teorētiskajā daļā tiek apskatīts autorfotogrāfijas jēdziens un nozīme, fotogrāfija kā komunikācijas līdzeklis, urbānās vides jēdziens, urbānā fotogrāfija un dažādu autoru viedokļi par to.
Darba koncepcijas daļā ir aprakstīta fotosērijas koncepcija, mērķis un vēstījums, izvirzīti uzdevumi, kas jāveic, lai sasniegtu darba mērķi un ieceri - iepazīties ar citu autoru līdzīgiem darbiem, metodēm; iepazīties ar teorijas materiāliem, kuros apskatīta autorfogrāfija un fotogrāfija kā komunikācijas līdzeklis; iepazīties ar teorijas materiāliem par urbāno vidi; izveidot radošā darba konceptu; doties izpētīt un fotografēt novada teritoriju; apstrādāt uzņemtās fotogrāfijas; izdarīt secinājumus.
Mērķis: izveidot fotosēriju par Madonas novada urbāno vidi autorfotogrāfijā. Bakalaura darba noslēgumā izdarīti secinājumi.ANNOTATION
A bachelor’s degree creative dissertation on “Representation of the urban environment of the administrative territories of Madona municipality in a author photography” is developed based on author's photography, which represent a subjective view of the urban environment of Madona county from the perspective of the author.
It is important to be aware of our environment and get to know it from different angles, later, as the region develops and the world's urbanization changes, these photos will serve as historical evidence of this time.
The bachelor thesis consists of a theoretical part and a creative concept part. The theoretical part examines the concept and meaning of author photography, the role of photography in communication, the concept of urban environment, urban photography and the opinions of various authors about it.
The concept part of the work describes the concept, aim and message of the photo series. Several tasks were performed in order to achieve the goal and intention of the work – to research the work and methods of other authors; research the theory materials, which discuss author photography and the role of photography in communication; to research theoretical materials about the urban environment; Create a concept of creative work; to explore and photograph the territory of the county; to take photos and process them; to come to conclusion about the theoretical and conceptional parts of creative work.
The goal is to draw the attention of the residents of the county with the help of a photo series and introduce the urban environment of Madona county through the author's subjective point of view.
The conclusion can be found at the end of this dissertation
A different view on light element anti-correlations in globular clusters: Fluorine abundances in NGC 6656 (M22)
No full textObserved chemical (anti)correlations in the light elements C, N, O, Na, Mg, and Al among globular cluster (GC) stars are presently recognised as the signature of self-pollution from previous generations of stars. This defines the multiple population scenario (MPS). Since fluorine is involved in the complete CNO cycle, determining its abundance in GCs provides new and complementary clues regarding the nature of these previous generations. In fact, along with the Na-O and Mg-Al anti-correlations, the MPS also predicts an anti-correlation between F and Na and a positive correlation between F and O. Furthermore, theoretical models suggest that low-mass (≲5Mȯ) asymptotic giant branch (AGB) stars are F producers (and are also responsible for C+N+O and s-process element variations). We present our results on near-infrared CRIRES spectroscopic observations of six giant stars in the metal-poor GC NGC 6656 (M22): we aim at inferring the F content and its (possible) variation in this GC, which exhibits a rather peculiar abundance pattern, with variations in both light (C, N, O, Na, Mg, Al) and heavy (Fe-peak and s-process) elements. © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence.SCOPUS: cp.pinfo:eu-repo/semantics/publishe
Magnesium Isotopic Abundance Ratios in Cool Stars
No full textFrom high-resolution spectra of 61 cool dwarfs and giants, Mg isotopic abundance ratios24Mg:25Mg:26Mg are derived from spectral synthesis of the MgH A-X lines near 5140 Å. Our sample spans the range -2.5 ≤ [Fe/H] ≤ 0.1, including the first measureme
The performance and architecture of column oriented database
No full textBakalaura darbs ir veltīts vertikālu datu bāzu izmantošanas problemātikai. Darbā ir apkopota informācija par kolonnu-orientētām datu bāzēm, salīdzinājumā ar rindu-orientētām datu bāzēm, ņemot vērā galvenos datu bāzu darbības parametrus: apstrādes ātrumu pēc laika un vietu, kuru aizņem dati. Pirmajās trīs nodaļās tiek teorētiski izklāstīti datu bāzu pamati, bet pēdējā nodaļā notiek divu datu bāzu praktiska salīdzināšana, izejot no teorētiskā apraksta. Darbā ir apskatītas Sybase IQ un Oracle Express; to galvenās īpašības un kādiem nolūkiem tās tiek pielietotas.
Praktiskajā nodaļā ir aprakstīta datora konfigurācija testiem, testu apraksti, datu bāzu instalācijas norādījumi, testa datu parametri, kā arī izveidotas testa datu bāzes, lai izpētītu to galvenās īpašības un priekšrocības.
Kopumā darbs satur 57 lapas, 29 attēlu, 12 tabulas, 3 piemērus, 3 pielikumus un 18 bibliogrāfiskus avotus.The present bachelor paper is devoted to the problem of column-oriented database performance. The author of the paper analyzed the information on column-oriented database. To reach the aim of the paper, the author compared the aforementioned database to row-oriented database, taking into consideration the main database performance parameters (performance according to time and space occupied on the hard disc drive).
The present work consists of four chapters. First three chapters outline in theory database fundamental principles; in the last concluding part the author compares theoretically and practically two different types database architectures. The paper studies Sybase IQ and Oracle Express, their main features and what purposes and tasks they are used for.
In the practical part the author examines computer’s configurations for tests, description of tests, guidelines for database installation, test data parameters as well as creates database explores its main qualities and advantages.
The work contains 57 pages, 29 pictures, 12 tables, 3 appendices and 18 bibliographical sources
Chemical Compositions of Red Giant Stars in Old Large Magellanic Cloud Globular Clusters
No full textNRC publication: Ye
Finding a path in a maze
No full textDarbs demonstrē, kā var izmantot viļņu algoritmu ceļa atrašanai labirintā. Darbā tiek izpētīts viļņu algoritms, rezultātā ir izveidota lietotne, kurā ir realizēts viļņu algoritms un trīs tā modifikācijas. Salīdzinot modifikācijas, tiek secināts, ka 3. modifikācija ir visefektīvākā.The present research paper deals with the investigation of wave algorithm for the solving of mazes. The paper aims to create a program that finds a path in the maze. Moreover, it aims to modify wave algorithm and to compare the wave algorithm and the productivity of its modifications. The author of the paper developed the program for maze solving. Moreover, the wave algorithm and its modifications were implemented. The study has shown that third modification was the most effective
Contemporary Russian Cartoons as Postmodern Texts .
No full textBakalaura darbs ir veltīts postmodernisma iezīmju pētījumam mūsdienu krievu animācijās filmās. Autors veic dažādu krievu animācijas filmu analīzi un meklē postmodernisma pazīmes. Mūsdienu krievu animācijas filmas tiek pētīti kā postmodernisma teksti. Tiek analizēti četri teksti, kuri balstās uz krievu tautas pasakām : Kā noķert «Ugunsputna spalvu», «Ivans Caradēls un Vilks pēlecis», «Ivans Caradēls un Vilks pēlecis 2» , «Ivans Caradēls un Vilks pēlecis 3». Īpaša uzmanība tiek pievērsta animācijas varoņiem un animācijas sižetam. Pētījums var ieinteresēt filologus, kuri nodarbojas ar postmodernisma pētījumiem, kā arī tos, kuri pēta krievu burvju pasakas.The bachelor paper is devoted to the research of the phenomenon of the postmodernism in contemporary Russian cartoons. The author reveals the most significant features of the postmodernism. Contemporary Russian cartoons are analyzed as the postmodern texts. The analyzed cartoons that are based on the Russian fairytales are the following: How to catch a Fire Bird’s feather, Tsarevitch Ivan and the Gray Wolf, Tsarevitch Ivan and the Gray Wolf 2, Tsarevitch Ivan and the Gray Wolf 3.The special attention is paid to the main characters and to the plot of the cartoons. The present research can be interesting for the philologist who study the postmodernism and Russian fairytales
Mobilo lietotņu testēšana.
No full textDarbā ir sniegts pārskats par programmatūras testēšanu metalīmenī. Autors ir izpētījis aspektus, kas ietekmē funkcionālo testēšanu jo īpaši iOS lietotnēm, kā arī mobilajām lietotnēm kopumā. Darbā ir izpētītas arī drošības iespējas un izstrādes/testēšanas “pārpalikumi”, kas bieži tiek atstāti bez ievērības un nesakārtoti lietotņu ātrākai pieejamībai tirgū. Atsevišķa nodaļa ir veltīta mobilo lietotāju saskarņu automātisko testēšanas rīku pētīšanai un klasterizācijai. “Ārā no kastes” Apple UIAutomation rīka ierobežojumu pārvarēšana ir apvienota tTap ietvarā, kuru izstrādāja autors. Analizējot paveikto, tika izveidots “ideāla” starpplatformu mobilo lietotāja saskarnes testēšanas automatizācijas rīka priekšlikums. Promocijas darbam piemīt praktiskais raksturs. Visa ar mobilo lietotņu testēšanas saistītā informācija tika savākta vai pārbaudīta reālo mobilo lietotņu projektu izstrādes laikā.The thesis gives an overview of software testing on the meta-level. Aspects that influence functional testing of iOS apps in particular, and mobile – in general, were investigated by the author. The thesis also exposes the security capabilities and development/ testing leftovers that often are neglected and not cleaned up in favor of time to market rush. A separate chapter of the thesis deals with mobile UI test automation tools investigation and clustering. Solutions aimed at overcoming the limitations of out of the box Apple UIAutomation are united in tTap framework developed by the author. The analysis performed on mobile UI test automation tools united with the solutions used in tTap framework resulted in the ideal cross-platform mobile UI test automation tool proposal. The whole thesis has a practical flavor. All mobile testing related information has been verified or gathered during the real mobile software development projects executio
Partnerattiecību institūts – problēmjautājumi un tiesiskā regulējuma pilnveide Latvijas Republikā. Promocijas darba kopsavilkums
No full textThe Doctoral Thesis was developed at Rīga Stradiņš University, Latvia. Defence: at the public session of the Doctoral Committee of Legal Sciences on 14th April 2022 at 14.00 online in Zoom platform.Partnership Institute – issues and improvement of legal framework in the Republic of Latvia Both free movement of people and easier people-to-people contacts (the liberalisation of relationships) have put the rights to respect for private life, home and correspondence, including ‘family life’, on the agenda. Today’s social reality calls for the revision of family law and the solution of property matters according to society’s needs. These issues are relevant not only for Latvia but also for other countries that have not yet introduced a legal framework dealing with cohabitation, with the result that an unmarried relationship between two persons starting a family in one way or another is not recognised by law. The legalisation of same-sex cohabitation by means of national law is even more controversial. There is still a broad debate observed in the public domain regarding the necessity of a special cohabitation legislation to ensure equal legal security for families, irrespective of whether or not they are registered from the legal point of view. The objective of the doctoral thesis – to identify issues concerning the scope of a family in the context of cohabitation by analysing the doctrine of the institution of cohabitation and foreign legislation and formulate recommendations for improvement of cohabitation laws in Latvia’s legal system. The doctoral thesis analyses both the existing legislation and case law and studies available in Latvia to pinpoint the main legal problems faced by cohabiting couples and suggest potential solutions. In Latvia, there are people who prefer cohabitation for various reasons, thereby starting a family that is not based on the institution of marriage. As already mentioned, marriage between a man and a woman is the only way of living together recognised by law in the Republic of Latvia. Nevertheless, many have started a family without registering their relationship officially according to part one “Family Law” of the Civil Law. Therefore, such a union between people is regarded as controversial with respect to the institution of family according to law. This means that unregistered cohabitation is increasingly prevalent in society, leading to certain inconsistency in a number of fields of law, such as inheritance, the rights of patients and their protection, people’s social rights, the right of information, procedure law, etc. This is important in situations when unregistered family ties disintegrate, there are disputes over cohabiting partners’ property division, fulfilment of obligations, subsequent care for the partners’ children, etc. Legislative amendments suggested by the author would provide a more equal legal treatment of cohabiting and married couples. Introducing cohabitation rules would ensure a uniform framework in the field of family law, which would solve current issues arising due to the lack of legislation or interpretation and, accordingly, inconsistent case law, and provide a legal basis for situations that are not yet dealt with by law
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