In this article, we propose an overview of missing data problem, introduce three missing data mechanisms and study general solutions to them when estimating a linear regression equation. When we have partly missing data, there are two common ways to solve this problem. One way is to ignore those records with missing values. Another method is to impute those observations being missed. Imputation methods arepreferred since they provide full datasets. We observed that there is not a general imputation solution in missing not at random (MNAR) mechanism. In order to check the performance of existing imputation methods in a regression model, a simulation study is set up. Listwise deletion, simple imputation and multiple imputation are selected into comparison which focuses on the effect on parameter estimates and standard errors. The simulation results illustrate that the listwise deletion provides reliable parameter estimates. Simple imputation performs better than multiple imputation in a model with a high determination coefficient. Multiple imputation,which offers a suitable solution for missing at random (MAR), is not valid for MNAR.

The aim of this study is to present a contrastive analysis of verbal complement that-clauses in English and Lithuanian and to describe, contrast and compare the cases of that deletion in them on the basis of corpus evidence. Matrix verbs from three semantic domains, viz. saying, thinking, and discovering, were investigated in the spoken, fiction, newspaper, and magazine registers of the BNC and LLC corpora. The methods chosen for the study were qualitative analysis as well as contrastive and content analysis. The corpus evidence demonstrated that zero-that complement clauses are by far more frequent in English than in Lithuanian in all registers considered. The deletion of that in Lithuanian appeared to be likely in case the complement clause is preceded by an evidential marker, such as esą, neva “supposedly”, girdi “(you) hear”, tarsi, lyg “as if”, or gal “maybe”, adopting the function of the complementizer, which is not the case in English. The corpus evidence also revealed that in both languages complement zero-that clauses share a structural peculiarity known as closeness of the clause juncture and are likely to occur with the most frequent verbs in both languages: say, think, and know. Another similarity is that in both languages matrix clauses followed by zero-that complements can be confused with comment clauses. Further quantitative corpus-based researches of Lithuanian complement clauses must be carried out in order to measure the influence of the contextual factors... [to full text] / Šio tyrimo tikslas – išanalizuoti anglų bei lietuvių kalbos prijungiamuosius aiškinamuosius sakinius bei remiantis tekstynų duomenimis aprašyti ir palyginti jungtuko kad/jog praleidimo atvejus tokio tipo sakiniuose. Aiškinamieji sakiniai, valdomi kalbėjimo, mąstymo bei suvokimo veiksmažodžių, buvo išnagrinėti BNC ir LLC tekstynų šnekamosios kalbos, grožinės literatūros bei publicistikos registruose. Tyrimas grindžiamas lyginamosios ir kontekstinės analizės metodais bei kokybinės analizės metodu aprašant ir lyginant iš tekstynų surinktus duomenis. Surinkti tekstynų duomenys rodo, kad prijungiamieji aiškinamieji sakiniai su praleistu jungtuku kad/jog žymiai būdingesni anglų nei lietuvių kalbai. Paaiškėjo, kad jungtuko kad/jog nebuvimas lietuvių kalboje tikėtinas, jei šalutinis dėmuo pradedamas evidencialumo raiškos priemonėms priskiriamais žodžiais esą, neva, lyg, tarsi ir girdi, kurie šiuolaikinėje lietuvių kalboje neretai atlieka jungtukų funkciją, bet anglų kalbai tokios struktūros nebūdingos. Abiejose kalbose jungtukas kad/jog dažniau praleidžiamas su dažniausiai kalboje vartojamais veiksmažodžiais. Anglų ir lietuvių kalbos bejungtukiai aiškinamieji sakiniai taip pat panašūs sandaros atžvilgiu: nėra antros eilės sakinio dalių, įsiterpiančių tarp valdančiojo veiksmažodžio ir šalutinio dėmens veiksnio. Be to, abiejose kalbose būna dviprasmiškų atvejų, kai bejungtukių aiškinamųjų sakinių pagrindinį dėmenį sunku atskirti nuo įterpinio arba komentuojamojo sakinio. Tam, kad... [toliau žr. visą tekstą]

Insertions/deletions (indels) are potentially powerful evolutionary markers, but little is known about their evolution and few tools exist to effectively study them. To address this, I developed SeqFIRE, a tool for automated identification and extraction of indels from protein multiple sequence alignments. The program also extracts conserved alignment blocks, thus covering all major steps in preparing multiple sequence alignments for phylogenetic analysis. I then used SeqFIRE to build an indel database, using 299 single copy proteins from a broad taxonomic sampling of mainly multicellular eukaryotes. A total of 4,707 indels were extracted, of which 901 are simple (one genetic event) and 3,806 are complex (multiple events). The most abundant indels are single amino acid simple indels. Indel frequency decreases exponentially with length and shows a linear relationship with host protein size. Singleton indels reveal a strong bias towards insertions (2.31 x deletions on average). These analyses also identify 43 indels marking major clades in Plantae and Fungi (clade defining indels or CDIs), but none for Metazoa. In order to study the 3806 complex indels they were first classified by number of states. Analysis of the 2-state complex and simple indels combined (“bi-state indels”) confirms that insertions are over 2.5 times as frequent as deletions. Three-quarters of the complex indels had three-nine states (“slightly complex indels”). A tree-assisted search method was developed allowing me to identify 1,010 potential CDIs supporting all examined major branches of Plantae and Fungi. Forty-two proteins were also found to host complex indel CDIs for the deepest branches of Metazoa. After expanding the taxon set for these proteins, I identified a total of 49 non-bilaterian specific CDIs. Parsimony analysis of these indels places Ctenophora as sister taxon to all other Metazoa including Porifera. Six CDIs were also found placing Placozoa as sister to Bilateria. I conclude that slightly complex indels are a rich source of CDIs, and my tree-assisted search strategy could be automated and implemented in the program SeqFIRE to facilitate their discovery. This will have important implications for mining the phylogenomic content of the vast resource of protist genome data soon to become available.

The main goal of this thesis is to investigate the nature of an optional consonant deletion process, through an articulatory and acoustic study of word-final consonant clusters in Persian. Persian word-final coronal stops are optionally deleted when they are preceded by obstruents or the homorganic nasal /n/. For example, the final clusters in the words /næft/ “oil”, /suχt/ “burnt” and /qæsd/ “intention” are optionally simplified in fast/casual speech, resulting in: [næf], [suχ], and [qæs]. What is not clear from this traditional description is whether the coronal stop is truly deleted, or if a coronal gesture is produced, but not heard, because it is obscured by the adjacent consonants. According to Articulatory Phonology (Browman & Goldstein 1986, 1988, 1989, 1990a, 1990b, 1992, 2001), the articulatory gestures of the deleted segments can still exist even if the segments are not heard. In this dissertation, ultrasound imaging was used to determine whether coronal consonant deletion in Persian is categorical or gradient, and the acoustic consequences of cluster simplification were investigated through duration and spectral measures. This phonetic study enables an account for the optional nature of the cluster simplification process. A general phonological account is provided for the simplification of coda clusters with rising sonority, and the acoustic and articulatory investigation focuses on the simplification of clusters with coronal stops. Ten Persian-speaking graduate students from the University of Ottawa and Carleton University, five male and five female, aged 25-38 participated in the articulatory and acoustic study. Audio and real time ultrasound video recordings were made while subjects had a guided conversation with a native speaker of Persian. 662 tokens of word-final coronal clusters were auditorily classified into unsimplified and simplified according to whether they contained an audible [t]. Singleton coda consonants and singleton /t/s were also captured as controls. The end of the constriction plateau of C1 and beginning of constriction plateau of C3 were used to define a time interval in which to measure the coronal gesture as the vertical distance between the tongue blade and the palate. Smoothing Splines ANOVA was used in a novel way to compare tongue blade height over time across the three conditions. The articulatory results of this study showed that the gestures of the deleted segments are often still present. More specifically, the findings showed that of the clusters that sounded simplified, some truly had no [t] gesture, some had gestural overlap, and some had reduced gestures. In order to explain the optional nature of the simplification process, it is argued that the simplified tokens are the result of two independent mechanisms. Inevitable mechanical and physiological effects generate gesturally reduced and overlapped tokens whereas planned language-specific behaviors driven by phonological rules or abstract cognitive representations result in no [t]-gesture output. The findings of this study support the main arguments presented in Articulatory Phonology regarding the underlying reasons for sound patterns and sound change. The results of this study are further used to examine different sound change models. It is argued that the simplified tokens with totally deleted [t] gesture could be the result of speakers changing their representations based on other people’s gestural overlap. This would be instances of the Choice and Chance categories in Blevins’ (2004) CCC sound change model. The acoustic results did not find any major cues which could distinguish simplified tokens from controls. It is argued that articulatory data should form an integral part of phonetic studies.

Ulm, Univ., Diss., 2008.

Zugl.: Berlin, Freie Universiẗat, Diss., 2008.

Thesis (Ph. D.)--University of Washington, 2008. / Vita. Includes bibliographical references (p. 91-99).

Thesis (Ph. D.)--Virginia Commonwealth University, 2007. / Prepared for: Dept. of Microbiology and Immunology. Bibliography: leaves 146-162. Available to VCU users online via the Internet.

Universiẗat, Diss., 2002--Bielefeld.

A presente dissertação origina-se de uma questão clínica a propósito do consumo de drogas na toxicomania servir de lenitivo para a angústia. Em vista disso, procura-se percorrer as vicissitudes do conceito de angústia nas obras de Freud e Lacan concomitante ao desenvolvimento do que ambos os autores falaram a respeito da função psíquica do recurso tóxico. Questiona-se o protagonismo conferido à substância tóxica na contemporaneidade como determinante para a instauração da toxicomania. Procura-se investigar em que medida a herança da psicanálise com a neurologia poderia oferecer dificuldades ao pesquisador psicanalítico na construção de suas elaborações a propósito da toxicomania. Logo em seguida, desenvolve-se a noção freudiana da indissociabilidade entre sensação e associação de forma que a interferência da droga sobre as condições de sensibilidade ultrapassa em grande medida sua influência, apenas, sobre um corpo-organismo.Busca-se apresentar e tecer alguns questionamentos acerca de elaborações de autores psicanalíticos a propósito da toxicomania. Para, por conseguinte, introduzir uma primeira articulação para a hipótese a respeito da qual o elemento de toxidade inerente à prática da droga produz um efeito de rasura sobre uma escrita composta de traços, a escrita psíquica. Escrita essa passível de leitura através das formações do inconsciente, todavia, não sem se opor ou oferecer resistência a sua decifração, a ponto de tornar impossível uma interpretação definitiva ou inequívoca. / The dissertation hereby arises from a clinic question regarding the drug usage in toxicomania used as a lenitive to anguish. With this is mind, it is intended to show the vicissitues of the concept of anguish in the work of Freud and Lacan, concurrent to what the both authors developed about the psychic function of the toxic. It is also questioned the role given to the toxic in contemporary society as the determinant to the establishment of addiction. It seeks to investigate to which extent the neurological psychoanalytic heritage can offer difficulties to the psychoanalytic researcher in the construction of addiction knowledge. After that, it is developed the Freudian notion of inseparability between feeling and association, in which the drug effect goes significantly beyond its influence on the body-organism. It seeks to present and to formulate some questions about the elaborations on addiction made by some psychoanalytic authors. With this, it is introduced one first articulation to the hypothesis on which the toxic element of the drug usage produces an effect of deletion on the writing composed by traces, the psychic writing. This writing is readable through the unconcious formation, however, not without opposition or resistance to its decipherment, to a level of becoming impossible an definitive or unequivocal interpretation.