Evento organizado por la Dirección de Gestión del Conocimiento - Biblioteca; el 29 de abril de 2022. Lima, Perú. Participaron: Camilo Torres (Colombia) - Ponente; Arturo Fernández (Perú) - Moderador / Con este webinar aprenderás a buscar y encontrar revistas y artículos científicos de las más prestigiosas editoriales en la base de datos Science Direct que serán de utilidad para tus trabajos de investigación y/o académicos.

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María Candela Blasco (Colombia) - Expositora / José Alvarez Masgo (Perú) - Moderador / Webinar enfocado en capacitar a los alumnos en el uso de la base de datos Capital IQ. En ella se enseñarán los pasos para acceder a una gran variedad de datos financieros, análisis e investigación.

Since the discovery in the early 1950's, frames have emerged as an important tool in signal processing, image processing, data compression and sampling theory etc. Today, powerful tools from operator theory and Banach space theory are being introduced to the study of frames producing deep results in frame theory. In recent years, many mathematicians generalized the frame theory from Hilbert spaces to Hilbert C*-modules and got significant results which enrich the theory of frames. Also there is growing evidence that Hilbert C*-modules theory and the theory of wavelets and frames are tightly related to each other in many aspects. Both research fields can benefit from achievements of the other field. Our purpose of this dissertation is to work on several basic problems on frames for Hilbert C*-modules. We first give a very useful characterization of modular frames which is easy to be applied. Using this characterization we investigate the modular frames from the operator theory point of view. A condition under which the removal of element from a frame in Hilbert C*-modules leaves a frame or a non-frame set is also given. In contrast to the Hilbert space situation, Riesz bases of Hilbert C*-modules may possess infinitely many alternative duals due to the existence of zero-divisors and not every dual of a Riesz basis is again a Riesz basis. We will present several such examples showing that the duals of Riesz bases in Hilbert $C^*$-modules are much different and more complicated than the Hilbert space cases. A complete characterization of all the dual sequences for a Riesz basis, and a necessary and sufficient condition for a dual sequence of a Riesz basis to be a Riesz basis are also given. In the case that the underlying C*-algebra is a commutative W*-algebra, we prove that the set of the Parseval frame generators for a unitary group can be parameterized by the set of all the unitary operators in the double commutant of the unitary group. Similar result holds for the set of all the general frame generators where the unitary operators are replaced by invertible and adjointable operators. Consequently, the set of all the Parseval frame generators is path-connected. We also prove the existence and uniqueness of the best Parseval multi-frame approximations for multi-frame generators of unitary groups on Hilbert C*-modules when the underlying C*-algebra is commutative. For the dilation results of frames we show that a complete Parseval frame vector for a unitary group on Hilbert C*-module can be dilated to a complete wandering vector. For any dual frame pair in Hilbert C*-modules, we prove that the pair are orthogonal compressions of a Riesz basis and its canonical dual basis for some larger Hilbert C*-module. For the perturbation of frames and Riesz bases in Hilbert C*-modules we prove that the Casazza-Christensen general perturbation theorem for frames in Hilbert spaces remains valid in Hilbert C*-modules. In the Hilbert space setting, under the same perturbation condition, the perturbation of any Riesz basis remains a Riesz basis. However, this no longer holds for Riesz bases in Hilbert C*-modules. We also give a complete characterization on all the Riesz bases for Hilbert C*-modules such that the perturbation (under Casazza-Christensen's perturbation condition) of a Riesz basis still remains a Riesz basis.

<p> This work was started to investigate new methods of synthesizing certain fulvenes. It was hoped that nucleophilic aromatic substitution of chlorine on 6,6-bis-(p-chlorophenyl) fulvene would provide an alternate route for the preparation of para-substituted 6,6-diphenyl fulvenes which had previously been prepared through the appropriately para-substituted benzophenone and cyclo-pentadienide (1,2). Attempts to prepare these substituted 6,6-diphenylfulvenes were unsuccessful.</p> <p> Secondly, a method of alkylating certain fulvenes in the cyclopentadiene ring was studied. With this in mind, 6,6-diphenylfulvene was treated with various nucleophiles which should give the relatively stable cyclopentadienide intermediate if the base adds to the exocyclic carbon atom. Alkylation of this anion, followed by expulsion of the nucleophilic group and a proton should then generate a new fulvene alkylated in the cyclopentadiene ring. In no case was any alkylated fulvene isolated. The major reaction products were two isomers of benzhydryl cyclopentadiene, rather than the expected alkylated fulvenes. The benzhydryl cyclopentadiene (mixture of two isomers) appears to have resulted from a reduction reaction.</p> <p> Since fulvenes of the type under study are generally unstable, an attempt was made to trap these alkylated fulvenes, if these were present, as their Diels-Alder adducts with tetracyanoethylene (TCNE). This attempt gave the adduct from one of the isomers of benzhydryl cyclopentadiene. The adducts from the other two possible isomers of benzhydryl cyclopentadiene were not detected. This result is an indication of the different reactivities of these isomers to TCNE.</p> <p> From the absence of TCNE adducts of the expected alkylated fulvenes, it was concluded that these fulvenes had not materialized in the attempted alkylation.</p> / Thesis / Master of Science (MSc)

<p> Several experimental situations were designed to show that when all visual, tactile and chemical stimuli are eliminated, fish are still capable of attracting one another and orienting to one another. Attempts to ascertain the nature of this unknown sensory basis of schooling were unsuccessful.</p> / Thesis / Master of Arts (MA)

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Polystyrene bis(salicylaldehyde)-propylene-1,3-diiminato Cobalt (II) (salen) and Polystyrene bis(acetylacetone)-propylene-1,3-diiminato Cobalt (II) (BAE) were prepared stepwise from polystyrl chloride. The reaction series included substitution of the chloride with a malononitrile carbanion, reduction to a diamine, condensation to form a Schiff base, and complexation with Co(II) acetate to form the active polymeric material. Optimum conditions with regard to time, temperature, reaction ratios, and solvent were determined for each reaction. The ability of the polymer bound cobalt complex to oxidize 3-methyl indole was measure. The BAE catalyst yielded a large amount of the corresponding o-formylaminoacetophenone. However, the exact yield is not known because product could not be separated from the indole. The salen catalyst showed starting material with a small indication of product.

The purpose of the thesis is to find out how to design column bases with conventional methods presented by European standards and codes, but above all from the Steel Construction Institute's handbook on structural joints and compare it with finite element analyses. However, today there are no good instructions for how column bases exposed to multiaxial bending should be designed, where assumptions based on structural mechanics also was compared with computer tools. The hand calculations are made in Excel and are something Northpower Stålhallar AB has requested, which will facilitate their work with design of column bases for VKR profiles placed at the middle, along one side, and at the corner of the plate. Several examples of column bases are touched upon in the work, with different load effects, as well as different dimensions of the column base, to assess how the result is affected. Examples of a dowel's bearing capacity are also treated. Finally, the calculations do not differ significantly from the results of the FE analysis at the smaller dimensions of the column foot, and that difference lies on the safe side with both uniaxial and multiaxial bending, as well as for transverse force capacity. The deviation for multiaxial bending was considerably larger, as the calculations were based on assumptions. The problem is that when bending in two directions, it is uncertain where the pressure resultant is located as the magnitude of the bending moment significantly affects the point of attack, while for uniaxial bending it can always be assumed that it is at the flanges.For the larger dimensions, however, it was the opposite, the FE analysis was on the safe side compared to the manual calculations. This makes the result extremely uncertain. The capacity differs at different dimensions of the column foot. The conclusion is that more calculations need to be made, as only a few were examined in this thesis, but based on these results, it is not appropriate to use manual calculations if it is this uncertain. When using a shear dowel, the tensile force on the anchor rods became significantly lower for the FE analysis, this is assumed to be due to the secondary force Nsec.Ed who can be added for design, which was neglected in the manual calculations. / Examensarbetets syfte är att ta reda på hur man dimensionerar pelarfötter med konventionella metoder som ingår i europeiska standarder och föreskrifter, men framför allt från Stålbyggnadsinstitutets detaljhandbok, och jämföra det med finita elementmetoden. Idag finns det dock inga anvisningar för hur pelarfötter utsatta för fleraxlig böjning skall dimensioneras, där antaganden också jämförs med datorverktyg. De analytiska beräkningarna är framställda i Excel och MathCad och är något Northpower Stålhallar AB har efterfrågat, som skall underlätta deras arbete med dimensionering av pelarfötter för VKR-pelarprofiler placerade vid mitten, långsidan och hörnet av fotplåten.Flera exempel på pelarfötter berörs i arbetet med olika lasteffekter, samt olika dimensioner på pelarfoten, för att bedöma hur resultatet påverkas. Ett exempel på en dymlings bärförmåga behandlas också. Slutligen är det tydligt att handberäkningarna inte differerar avsevärt från resultaten av FE-analysen vid den mindre dimensionen av pelarfoten, och den skillnaden ligger på den säkra sidan för handberäkningarna vid både enaxlig och fleraxlig böjning, samt för tvärkraftskapacitet. Avvikelsen för fleraxlig böjning var dock avsevärt större, då beräkningarna var baserade på antaganden. Problemet vid böjning i två riktningar är att det är osäkert vart tryckresultanten ligger då storleken av böjningarna påverkar angreppspunkten, medan för enaxlig böjning kan man alltid anta att resultanten är vid den tryckta flänsen.Med avseende på den större dimensionen var resultatet dock tvärtom, att FE-analysen låg på den säkra sidan gentemot handberäkningarna. Det här gör slutresultatet osäkert, då kapaciteten differerar vid olika dimensioner på pelarfoten. Slutsatsen är att det definitivt behöver göras fler beräkningar, då endast enstaka fall användes vid denna rapport, men utifrån resultatet från detta arbete är det inte lämpligt att använda handberäkningar ifall det är osäkert. Gällande dimensionering av en skjuvklack blev dragkraften på grundskruvarna betydligt lägre för FE-analysen, detta antas vara på grund av den sekundära kraften Nsec.Ed som kan användas vid dimensionering, vilket försummades vid handberäkningarna.