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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.
11

Språk- och kommunikationsutvecklingi förskolan : Med fokus på Tecken som Alternativ och Kompletterande Kommunikation

Steinwall, Lina, Åkerlund, Elinn January 2018 (has links)
För att idag kunna känna en delaktighet i samhället behöver varje människa kunna samspela. Detta samspel bygger på kommunikation med varandra. Det finns personer som har svårt för att kommunicera då det kan finnas ett språk och/eller en kommunikationsbarriär. För att komma över den här barriären kan man använda sig av stödtecken. I Sveriges förskolor arbetas det ibland med tecken som hjälpmedel. Denna teckenanvändning kallas för TAKK (Tecken som Alternativ och Kompletterande Kommunikation). Vårt syfte med rapporten var att ta reda på hur förskolor arbetar med tecken. Hur ofta de används, vad pedagogerna ser för utmaningar och möjligheter med det och om de anser att det kan vara till stöd för barnen i deras språk- och kommunikationsutveckling och i så fall på vilket sätt. För att få fram ett resultat utifrån detta syfte intervjuades sex stycken pedagoger i norra delen av Sverige. När vi analyserade intervjuerna gjorde vi en transkribering av vårt insamlade material. Därefter använde vi oss av fenomenografisk analysmetod. Detta kommer vi beskriva mer ingående i metodavsnittet. I resultatet framgick det att tecken endast användes i enstaka situationer men att pedagogerna skulle vilja arbeta mer med det. Pedagogerna såg många möjligheter med att använda TAKK och de menade bland annat att det kunde gynna barnens språkutveckling på olika sätt. Det fanns även utmaningar med TAKK som till exempel kunde vara att pedagogerna inte hade någon eller otillräckligt med utbildning inom TAKK vilket vi tolkar kan vara en nackdel. I rapporten kommer TAKK, tecken och tecken som stöd användas som synonymer.
12

Samverkan mot ökad punktlighet : Analys av TTT (Tillsammans för tåg i tid) / Collaboration towards improving punctuality : An analysis of TTT (Together for trains on time)

Brisère, Sophie January 2021 (has links)
The railway in Sweden has problems with punctuality, which creates additional costs forpassengers, operators and the infrastructure, which is a problem since a single actor cannotsolve alone. It is then required that more actors join forces and collaborate and for thisreason the industry has started a collaboration forum called TTT (Together for trains ontime). The purpose of this study is to contribute to an increased understanding of roles andresponsibilities in collaboration forum TTT (Tillsammans för tåg i tid). Collaboration isneeded as a single actor cannot solve various problems by themselves. Collaboration is usedbetween organizations to handle different types of problems and processes.Previous research shows that collaboration in the rail traffic is very important, as there aremany complex systems with several actors involved. This study examines how collaboration works in practice by examine the collaborationforum TTT, Tillsammans för tåg i tid. This is done partly through a survey and partlythrough a semi-structured interview.Through analysis of the case study TTT, interview, survey and application of the chosentheoretical framework, this study has increased the understanding of how collaborationworks in practice.The results show that collaboration has generally worked well and that it has beenbeneficial working towards improving punctuality / Järnvägen i Sverige har problem med punktlighet vilket skapar merkostnader för resenärer,operatörer och infrastrukturförvaltare, vilket är ett problem då en ensam aktör inte kanlösa detta själv. Det krävs då att fler aktörer går ihop och samverkar och av denna anledninghar branschen startat ett samverkansforum som benämns TTT (Tillsammans för tåg i tid). Syftet med denna studie är att bidra till ökad förståelse kring roller och ansvar ibranschsamarbete TTT (Tillsammans för tåg i tid). Samverkan sker mellan organisationerför att hantera olika typer av problem och processer.Tidigare forskning visar att samverkan inom tåg- och järnvägstrafiken är väldigt viktigt, dådet är många komplexa system med flera aktörer involverade. Denna studie undersöker hur samverkan fungerar i praktiken genom att studerasamverkanforumet TTT, Tillsammans för tåg i tid. Detta görs dels genom enenkätundersökning och dels genom en semistrukturerad intervju.Genom analys av fallstudien TTT, intervju, enkätundersökning och tillämpningen av devalda teoretiska ramverk har denna studie ökat förståelsen för hur samverkan fungerar ipraktiken. Resultatet visar att samverkan i stora drag har fungerat bra och att den varitfördelaktig för att öka punktligheten.
13

Análise microestrutural em altas temperaturas de um ferro fundido branco de alto cromo com molibdênio e nióbio / A molybdenum and niobium high chromium white cast iron study-metallography at high temperatures

Silva, Cloir Salatiel da 15 October 1999 (has links)
As mudanças microestruturais, causadas pela adição de elementos de liga e pelos tratamentos térmicos, modificam as propriedades mecânicas e tribológicas dos materiais. Foi desenvolvido então um estudo em amostras de um ferro fundido branco de alto cromo com molidbênio e nióbio, procurando determinar os efeitos dos elementos de liga molibdênio e nióbio, na microestrutura deste material, através de medidas de dureza, dilatometria, ataque químico, microscopia eletrônica de varredura e,principalmente, a utilização de metalografia em altas temperaturas. A técnica de metalografia em altas temperaturas permite o estudo das mudanças microestruturais durante os ciclos térmicos, que foram programados, tendo como referência a curva TTT previamente traçada para este material, focalizando regiões onde não ocorrem mudanças de fase. Deste modo foram obtidas as aparências metalográficas em altas temperaturas e feito um estudo comparativo com as outras técnicas usadas. Com isto é possível melhorar o conhecimento sobre a microestrutura do material em questão e obter ligas com propriedades pré-determinadas. / The microstructural changes caused by the addition of alloying elements and by thermal treatments modify the mechanical and tribological properties of the materials. A study was develop on samples of molybdenum and niobium high chromium white cast iron, trying to determine the effects of molybdenum and niobium alloys elements on microstructure of this material through hardness measurements, dilatometry, chemical etching, scanning electron microscopy, and mainly, utilizing metallography at high temperatures. The metallography at high temperatures technic allows the study of microstructural changes during the thermal cyc1es, which were scheduled, having as reference the TTT curve previously traced to this material, focusing regions where changes of fase don\'t occur. So the metallographic appearances at high temperatures were obtained and it was done a comparative study using other technics. Because of that is possible to improve the knowledge of the material microstructure, which it has been studied, and to obtain alloys with predetermined properties.
14

Análise microestrutural em altas temperaturas de um ferro fundido branco de alto cromo com molibdênio e nióbio / A molybdenum and niobium high chromium white cast iron study-metallography at high temperatures

Cloir Salatiel da Silva 15 October 1999 (has links)
As mudanças microestruturais, causadas pela adição de elementos de liga e pelos tratamentos térmicos, modificam as propriedades mecânicas e tribológicas dos materiais. Foi desenvolvido então um estudo em amostras de um ferro fundido branco de alto cromo com molidbênio e nióbio, procurando determinar os efeitos dos elementos de liga molibdênio e nióbio, na microestrutura deste material, através de medidas de dureza, dilatometria, ataque químico, microscopia eletrônica de varredura e,principalmente, a utilização de metalografia em altas temperaturas. A técnica de metalografia em altas temperaturas permite o estudo das mudanças microestruturais durante os ciclos térmicos, que foram programados, tendo como referência a curva TTT previamente traçada para este material, focalizando regiões onde não ocorrem mudanças de fase. Deste modo foram obtidas as aparências metalográficas em altas temperaturas e feito um estudo comparativo com as outras técnicas usadas. Com isto é possível melhorar o conhecimento sobre a microestrutura do material em questão e obter ligas com propriedades pré-determinadas. / The microstructural changes caused by the addition of alloying elements and by thermal treatments modify the mechanical and tribological properties of the materials. A study was develop on samples of molybdenum and niobium high chromium white cast iron, trying to determine the effects of molybdenum and niobium alloys elements on microstructure of this material through hardness measurements, dilatometry, chemical etching, scanning electron microscopy, and mainly, utilizing metallography at high temperatures. The metallography at high temperatures technic allows the study of microstructural changes during the thermal cyc1es, which were scheduled, having as reference the TTT curve previously traced to this material, focusing regions where changes of fase don\'t occur. So the metallographic appearances at high temperatures were obtained and it was done a comparative study using other technics. Because of that is possible to improve the knowledge of the material microstructure, which it has been studied, and to obtain alloys with predetermined properties.
15

Precipitation behavior of the super austenitic stainless steel SANICRO® 35 and the effect on impact toughness and pitting corrosion resistance

Li, Shunyi January 2022 (has links)
This research extended the knowledge of the solid phase transformation and the resulting influence on impact toughness and pitting corrosion resistance in super austenitic stainless steel (SASS) SANICRO® 35. A time-temperature-transformation diagram (TTT diagram) was assembled by performing isothermal heat treatments in the temperature range of 650-1050 °C for different periods of time, ranging from 5 min to 500 min. Microstructural analysis via LOM-DIC, SEM-EDS shows that the nose temperature of dominating σ phase is located in between 900-950 °C. Minor nitrides including π phase and Cr2N with the nose temperature of 900 °C and 850 °C, respectively, were detected after prolonged heat treatment times. Area fraction of precipitates was calculated by analyzing micrographic images in the software ImageJ. Charpy impact tests indicate that the impact toughness degrades with increasing area fraction of precipitates but at a higher rate at the early stage of precipitation. Despite a much-lessened area fraction, fine precipitates decorating the grain boundaries in a continuous pattern impose significant negative effect on impact toughness. Pitting corrosion resistance was indicated by critical pitting temperature (CPT) as per ASTM G150mod (3M MgCl2). Pitting corrosion resistance deteriorated with increasing amount of σ phase due to the Cr- and Mo-depleted surrounding area, but it is more dependent on the distribution pattern of precipitates, as well as the secondary phase type. The lowest CPTs were measured after heat treatment for 500 min at 800 °C and 850 °C where nitrides including Cr2N and π phase were formed and the small precipitates were distributed on grain boundaries continuously. Auxiliary simulation of TTT diagram via TC PRISMA shows drastic variation from experimental results in regard of time scale. The enhancement pre-factor for the interfacial mobility and interfacial energy can be modified to approach the experimental results. / Detta arbete utfördes för att undersöka fasomvandlingar och dess inflytande på slagsegheten och gropfrätningsmotståndet för det superaustenitiska rostfria stålet (SASS) SANICRO® 35. Ett tid-temperatur-transformationsdiagram (TTT-diagram) har tagits fram genom att utföra isotermiska värmebehandlingar mellan 650-1050 °C med olika hålltider från 5-500 minuter. Mikrostrukturanalys genom LOM-DIC, SEM-EDS undersökning visar att nosen för den dominerande σ-fasen ligger mellan 900-950 °C. Mindre nitrider, som π-fas och Cr2N, med nosarna vid 900 °C respektive 850 °C observerades vid längre hålltider. Areafraktionen av utskiljningar beräknades genom analys av mikrobilder med programmet ImageJ. Slagprovning visade att slagsegheten minskar med ökande fraktion utskiljningar men med en tydligare försämring i början av fastransformationen. Trots att de utgör en betydligt mindre areafraktion så kan mindre utskiljningar som följer korngränserna också påverka materialet signifikant negativt. Gropfrätningsmotståndet testades genom att mäta Critical Pitting Temperature (CPT) enligt ASTM G150mod (3M MgCl2). CPT minskade med ökande andel σ-fas p.g.a. den Cr- och Mo-utarmade zon som omger de utskilda partiklarna. Det finns även en stark koppling mellan lägre CPT och distributionen av utskiljningarna samt andra typer av faser. Lägst CPT uppmättes efter 500 minuter vid 800 °C och 850 °C då små nitrider inklusive Cr2N och π-fas bildats längs med stora delar av korngränserna. Simulering av TTT-diagram i TC PRISMA visade en drastisk skillnad i tiden till utskiljning/mängden utskiljningar jämfört med de experimentella resultaten. Diffusionförstärkningsfaktorn (eng. “mobility enhancement pre-factor”) och ytenergin kan minskas för att bättre överensstämma med de experimentella resultaten.
16

Etude et compréhension des mécanismes de vieillissement des alliages de plomb-calcium

Rossi, Frédéric 11 December 2006 (has links) (PDF)
Les données de la littérature concernant le vieillissement et le survieillissement des alliages plomb-calcium sont bien souvent incomplètes et contradictoires. Ceci est certainement lié aux difficultés expérimentales rencontrées pour observer les transformations et le fait que celles-ci sont nombreuses, entraînant une certaine confusion dans les travaux des auteurs. De plus, de faibles écarts dans les conditions d'élaboration et dans la composition des alliages peuvent avoir de l'importance sur leur comportement. Le présent travail, réalisé pour le CEA-DAM, nous a permis d'obtenir un ensemble de diagrammes TTT plus réalistes et plus justes que ceux donnés dans la littérature. Les moyens techniques mis en place (en particulier, la préservation de la chaîne du froid, condition indispensable pour garantir la répétabilité des résultats), nous ont permis d'étudier plus particulièrement les premières transformations et de mieux maîtriser les cinq étapes de vieillissement et de survieillissement. Nos travaux ont permis de déterminer clairement les cinétiques et les mécanismes des transformations. Ce travail constitue un approfondissement de la compréhension des phénomènes de vieillissement et de survieillissement de ces alliages.
17

Modulation of the actin cytoskeleton in the folliculo-stellate cell line TtT/GF by serum factors

Zheng, Guifu January 2005 (has links)
Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.
18

Application of Computational Thermodynamic and Solidification Kinetics to Cold Sprayable Powder Alloy Design

Belsito, Danielle L 14 January 2014 (has links)
Military aircraft that require high maneuverability, durability, ballistic protection, reparability, and energy efficiency require structural alloys with low density, high toughness, and high strength. Also, repairs to these aircraft demand a production process that has the flexibility to be relatively in-situ with the same high-performance output. Materials produced by the cold spray process, a thermo-mechanical powder consolidation technique, meet many of the requirements. In accordance with President Obama’s 2011 Materials Genome Initiative, the focus of this effort is to design customized aluminum alloy powders which exploit the unique behavior and properties of the materials created by the cold spray process. Analytical and computational models are used to customize microchemistry, thermal conditioning, and solidification behavior of the powders by predicting equilibrium and non-equilibrium microstructure and resulting materials properties and performance. Thermodynamic, kinetic, and solidification models are used, including commercial software packages Thermo-Calc, Pandat™, and JMatPro®, and TC-PRISMA. Predicted powder properties can be used as input into a cold spray process impact model to determine the consolidated materials’ properties. Mechanical properties of powder particles are predicted as a function of powder particle diameter and are compared to experimental results.
19

Caractérisation morphologique, biochimique et physiologique des protéines de jonction lacunaire, les connexines 46 et 50, dans les cellules folliculo-stellaires TtT/GF de l’hypophyse antérieure

Garcia, Christopher 04 1900 (has links)
Les cellules folliculo-stéllaires (FS) de l'hypophyse antérieure possèdent une forme étoilée et étendent de longues projections cytoplasmiques qui forment des pseudo-follicules entourant les cellules endocrines. Les cellules FS sont connectées entre elles par des jonctions lacunaires (des fois aussi connu sous le nom de jonction communicante) formant ainsi un réseau tridimensionnel continu. Un des rôles principaux des cellules FS est le maintien du microenvironnement de l'hypophyse antérieure, une activité qui est en partie réalisée par la sécrétion de divers facteurs de croissance et de cytokines. Ces messagers chimiques, y compris le bFGF, le VEGF, l’IL-6 et l’IL-1 contrôlent de nombreux processus cellulaires tels que l’expression des gènes d’hormones. Notre intérêt est de déterminer si la communication entre les cellules FS contribue à leur activité régulatrice. Dans notre étude, nous avons utilisé la lignée cellulaire TtT/GF qui partage de nombreuses caractéristiques morphologiques, physiologiques et biochimiques avec les cellules FS. Les jonctions lacunaires/communicantes sont formées par l’association de deux connexons de cellules adjacentes qui unissent le cytoplasme des cellules connectées et permet la diffusion de petites molécules. Chaque connexon est formé par l’oligomérisation de six protéines connexine (Cx) de la famille α, β ou γ. Les connexons, intégrés dans la membrane d’une vésicule du cytoplasme, se migrent vers la membrane cellulaire où ils s’incorporent dans la couche bilipidique. L’expression de la Cx43 (α) par les cellules FS est régulée en réponse à des facteurs de croissance et des cytokines. Des changements dans le microenvironnement de l'hypophyse antérieure causés par des molécules de signalisation sont susceptibles de modifier la Cx43, en particulier l’état de phosphorylation de la protéine. Ces modifications de la Cx43 peuvent ensuite déclencher des changements du comportement de jonctions lacunaires/communicantes formées par la Cx43, comme leur perméabilité et le renouvellement de la protéine Cx43. Les tissus expriment généralement plus d’un type de connexine. Jusqu’aujourd’hui, la Cx43 est la seule connexine à avoir été identifiée dans les cellules FS. Le cristallin exprime les connexines α: Cx43, Cx46 et Cx50. Leur expression est modulée par des facteurs de croissance. Notre hypothèse de travail a été de vérifier si la Cx46 et la Cx50 étaient exprimées par les cellules FS et si celles-ci contribuaient au rôle modulateur des cellules FS hypophysaires. Dans cette étude, nous avons identifié et caractérisé la Cx46 et la Cx50 dans la lignée cellulaire TtT/GF. Nous avons identifié les produits de transcription de Cx46 et de Cx50 par la technique d’analyse northern blot (PCR). Par la suite, les protéines Cx46 et Cx50 ont été identifiées en utilisant des anticorps dans des analyses western blot. Par microscopie confocale, nous avons déterminé la co-localisation de la Cx46 avec certaines marqueurs d’organites : réseau trans-Golgien, endosomes précoces et lysosomes. La Cx50 co-localise avec des marqueurs du réticulum endoplasmique, du réseau cis-Golgien et des endosomes précoces. Un protocole d’isolation des membranes résistantes aux détergents non-ionique a révélé que la Cx46 et la Cx50 n’étaient pas associées à des radeaux lipidiques ni aux cavéoles. Cependant, la microscopie confocale a montré une co-localisation cytoplasmique de la Cx50 et de la flotilline-1. Nous avons poursuivi l’étude sur la localisation de la Cx46 dans le noyau en utilisant une technique d’isolation des fractions enrichies en noyau. Nous avons établi que plusieurs isoformes de la Cx46 sont exclusivement associées au noyau. De plus, avec la microscopie confocale nous avons démontrée une co-localisation de la Cx46 avec un marqueur du nucléole/corps de Cajal. Nous avons démontré un effet du bFGF sur l'expression temporelle de la Cx46 et de la Cx50. L’expression de la Cx46 diminue au cours de longues expositions au bFGF tandis que les niveaux de Cx50 augmentent de façon transitoire au cours du traitement. Dans une autre étude nous avons démontré des changements importants dans les niveaux de la Cx46 et de la Cx50 dans l’hypophyse antérieure des visons durant le cycle de reproduction annuel. Notre étude démontre que les cellules FS expriment la Cx46 et la Cx50. Nous avons aussi établi que la Cx46 et la Cx50 sont localisées dans différentes structures sous-cellulaires, ce qui suggère des rôles différents dans les cellules FS pour ces protéines de jonction lacunaire/communicante. Il est possible que la Cx46 et la Cx50 ne jouent pas un rôle majeur dans la communication intercellulaire dans les cellules FS quiescentes. Nos résultats suggèrent que la Cx46 et la Cx50 peuvent avoir d'autres fonctions : des isoformes de la Cx46 peuvent contribuer à la biogenèse des ribosomes tandis que la Cx50 pourrait avoir un rôle dans la communication dans les cellules stimulées au bFGF. Nos études établissent une base pour des recherches futures. / The folliculo-stellate (FS) cells of the anterior pituitary are star-shaped and extend long cytoplasmic processes forming pseudo-follicles encircling hormone-secreting cells. Dispersed throughout the anterior pituitary gland, FS cells are joined to form a continuous three dimensional network through communicating gap junctions. One of the primary roles of FS cells is the maintenance of the anterior pituitary microenvironment, accomplished through the expression and secretion of various growth factors and cytokines. These chemical messengers, including bFGF, VEGF, IL-6 and IL-1 mediate a range of cellular processes such as hormone gene expression. Our aim is to study whether intercellular communication among FS cells contributes to the modulatory activity of the FS cells within the anterior pituitary gland. To pursue this, we use the TtT/GF cell line that shares many morphological, physiological and biochemical characteristics with FS cells. Gap junctions are formed by the joining of two connexons/hemichanels from adjacent cells that link their cytoplasms allowing for the passive diffusion of small molecules. Connexons/hemichannels are themselves formed by the oligomerization of six connexin (Cx) proteins from the family α, β or γ, which then migrate into the lipid bilayer of the cell membrane. FS cells express Cx43 (α-connexin), which is regulated in response to growth factors and cytokines. Changes in the anterior pituitary microenvironment due to signaling molecules results in modifications to Cx43, particularly in the phosphorylation status of the protein. Such alterations yield alterations in the physiological behaviour of Cx43 gap junctions such as permeability and turnover. Tissues generally express more than one connexin type and to date, Cx43 has been the sole connexin to be identified in FS cells. The ocular lens expresses the α-connexins: Cx43, Cx46 and Cx50, which are modulated by growth factors that are also present in the anterior pituitary. Based on these facts, we hypothesize that Cx46 and Cx50 are also expressed by the FS cells and contribute to the FS modulatory role in the anterior pituitary gland. In the present study, we have identified and characterized Cx46 and Cx50 in the TtT/GF cell line. We identified Cx46 and Cx50 transcripts through northern blots and identified the corresponding protein products using antibodies and western blot analyses. Through confocal microscopy, we determined that Cx46 co-localized with the organelle markers: trans-Golgi, early endosomes and lysosomes. Cx50 co-localized with markers for the ER, cis-Golgi and early endosomes. An isolation procedure using a non-ionic detergent we showed that neither Cx46 nor Cx50 were associated to lipid rafts or caveolae. However, confocal microscopy showed a cytoplasmic co-localization between Cx50 and flotillin-1. We pursued a finding that localized Cx46 to the nucleus and using a nuclear isolation technique, demonstrated that several isoforms of Cx46 are exclusively located in the nuclear compartment. Furthermore, with confocal microscopy we found a co-localization of Cx46 with a nucleolus/coiled body marker. We demonstrated an effect of bFGF on the temporal expression patterns of Cx46 and Cx50 and showed that Cx46 levels decreased over longer exposures to the growth factor while Cx50 levels transiently increased. Lastly, drastic changes were noted in an in situ study of Cx46 and Cx50 in the male and female mink anterior pituitary during the annual reproductive cycle. Our study indicates that addition to Cx43, FS cells also express Cx46 and Cx50. We also demonstrated that Cx46 and Cx50 localize to different sub-cellular structures, suggesting different roles in the FS cells. While they may not play a major role in intercellular communication in quiescent FS cells, our results suggest that Cx46 and Cx50 may serve other functions: Cx46 isoforms may contribute to ribosome biogenesis and Cx50 may have communication-related responsibilities in stimulated cells. Importantly, our identification and characterization studies provide a foundation on which future studies can be built.
20

我國指數股票型基金上市後之績效分析

王韻晴 Unknown Date (has links)
從投資組合理論與效率市場假說來看,影響投資績效之主要因素為資產配置而非選股或擇時能力,相關之實証亦發現主動式投資策略並無法獲得持續優於大盤的報酬,因此被動式投資策略將是一較佳的選擇。自先鋒集團在1976年率先推出指數基金之後,此類指數化投資商品即呈現指數化成長。而我國亦在2003年6月30日正式推出第一檔指數股票型基金「臺灣50指數股票型基金,簡稱TTT」。 本論文以投資人的角度來分析TTT之報酬率及成交量,從追蹤誤差及溢折價來觀察基金之報酬率,研究造成追蹤誤差之主要影響因子為何與實物創造或贖回機制是否能有效發揮功用,使TTT之市價可貼進基金淨值,以免如同封閉型基金大都折價交易,而影響投資人之獲利率。此外,更進一步比較TTT與其他指數化商品之差異性以供投資人選擇投資標的時參考。 本研究發現影響追蹤誤差之因素主要為指數成份股之增刪、公眾流通係數之調整與現金股利的發放。雖然在短期下上述因素會影響基金報酬,但長期而言基金報酬與指數相當,甚或更為略高,故在衡量長期績效時臺灣50指數可做為一良好的報酬指標。而從溢折價來分析時,由於市場交易機制,使得TTT自上市以來之流動性不足,市場效率性不高,溢折價幅度較大。此點與成交量之分析結果一致,研究發現TTT之成交量並未因出現套利機會而顯著增加,投資人買賣TTT主要在於避險或投機需求。 雖然現階段我國尚未出現指數基金,但若未來有出現類似之商品時,在目前我國停徵證券交易所得稅的環境下,投資金額的大小將非決定選擇指數基金或TTT之關鍵因素,投資期間與「質」的因素才是主要關鍵。當投資期間愈長,TTT之高交易成本的影響程度將降低,其可在盤中隨時買賣及低追蹤誤差等「質」方面的優勢將提高,TTT將相對較具吸引力。而臺灣50指數期貨由於交易成本及流動性風險較高,因而投資人較不偏好操作臺灣50指數期貨。

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