Titanium dioxide nanotubes for production and delivery of nitric oxide and methods for production thereof

The present disclosure describes compositions operable for releasing nitric oxide under photochemical conditions. The compositions include a titanium dioxide nanomaterial and a nitric oxide-releasing compound deposited on the titanium dioxide nanomaterial that is operable to release nitric oxide under photochemical conditions. Titanium dioxide nanomaterials include, for example, titanium dioxide nanotubes. To facilitate the photochemical release of nitric oxide, some embodiments of the compositions further include a semiconductor that is deposited on the titanium dioxide nanotubes. Both the semiconductor and the nitric oxide-releasing compound may be deposited on the interior surface, exterior surface, or both of the titanium dioxide nanotubes. A polymer may wrap the titanium dioxide nanotubes to protect the nitric oxide-releasing compounds from moisture. Also disclosed herein are methods for producing such compositions and medical devices obtained therefrom.Board of Regents, University of Texas Syste

Understanding the digital divide: A literature survey and ways forward

The term digital divide was introduced in the mid-1990s and defined as the gap separating those who have access to new forms of information technology from those who do not. The digital divide remains an important public policy debate that encompasses social, economic and political issues. This paper presents a literature review and classification scheme for digital divide research. The review covers journal articles published between 2001 and 2010 in three types of journals: (1) Information technology & information systems, (2) Economics and business & management and (3) Social science. A classification of digital divide literature and a comprehensive list of references are provided. The results show that the digital divide is a multifaceted phenomenon, due to the many dimensions of determinant factors. Recent studies have included socio-economic, institutional and physiological factors in order to gain a greater understanding of the digital divide. Among other findings, they show that technological determinism is not sufficient to explain the emergence of the digital divide. Moreover, several types of technologies were investigated, both from empirical and conceptual standpoints. The Internet is the most commonly studied technology. The divide in access and usage are discussed at the global, social and democratic levels by employing a quantitative method, either a survey or data analysis, as the main method. However, there is less discussion in developing countries and at the level of the organization (i.e. SMEs, the private sector and the public sector). The qualitative research method could be seen as a complementary method to fill the gap in the current research. The choice of policies which have been recommended to the policy maker and national regulatory agency (NRA) are also presented and discussed at the end of this paper. Several initiatives made at the country and regional levels and by international organizations have also attempted to create a combined policy. This may suggest that the combined policy is the current trend among digital divide policies. Therefore, there is a need for future research to examine these determinants through the context of global, social and democratic divides. The results would provide some insight into how diverse people in different areas adopt ICTs. --Digital divide,Literature review,Future research

The Mobile Broadband and Fixed Broadband Battle in Swedish market: Exploring complementary or substitution

The mobile broadband (MBB) in Swedish market has become a more attractive opportunity for service providers, with growing demand for ubiquitous broadband connectivity after the mobile operators got 3G license in 2000. MBB seems to have more advantage compare to Fixed broadband (FBB) in term of mobility, compatibility and quality of service. This paper aims to explore the current broadband situation in Swedish market, in particular whether the mobile broadband is a complementary or substitute by using descriptive analysis. The data is collected from the Post- och telestyrelsen (PTS) Survey and the secondary data from PTS during 2002-2009. The findings indicate that the MBB and FBB subscribers remain growing, but the issue of complementary and substitution between MBB and FBB cannot be given an answer at this stage. The crucial problem of comparing MBB and FBB is the different units of measurement. Also, the potential of avoiding regulation by service providers is discussed since the market participants in FBB and MBB services are the same players. The rapid growth of MBB together with a lower degree of regulation in mobile services may attract the market player to put their effort more in MBB market. Moreover, the gap between broadband infrastructure coverage and the usage of this service is huge. Thus, the inefficiency of BB infrastructure utilization becomes another issue that NRAs could consider. --Mobile broadband,Fixed broadband,Complementary,Substitution

An analysis of mobile internet service in Thailand: Implications for bridging digital divide

Mobile Internet is growing around the world without exception for developing countries like Thailand by passing the poor legacy wired infrastructure. This study attempts to provide guidance to a national regulatory agency (NRA) by addressing the following question: What are the key determining factors to explain the probability that individual consumer will use mobile Internet? The discrete choice model is employed to empirically examine whether the service and application attributes, socio-economic variables and service provider has systematic link with the decision of consumer. The data from a national survey in 2010 commissioned by the National Telecommunications Commission (NTC) of Thailand is used for the analysis. Based on the findings, fixed telephony, e-mail, age, area of living and mobile operator are recognized as the strongest determinants for mobile Internet adoption. The findings suggest that the mobile Internet becomes an alternative technology to bridge the digital divide since a group of people who have no fixed Internet connection at home they can connect the Internet via mobile Internet. As such, telecom regulator and policy makers need to consider the policies regarding to infrastructure investment frequency allocation, content and application development and competition in order to stimulate the growth of mobile Internet adoption and close the digital divide within country. --Mobile Internet,digital divide,developing country

Workplace Injuries And Illnesses And Employer Costs For Workers’ Compensation

Depending on the circumstances surrounding an occupational injury or illness, employees may receive workers’ compensation benefits to replace lost wages and to pay for medical expenses. This Spotlight on Statistics looks at workplace injury and illness data and the costs to employers for workers’ compensation in natural resources, construction, and maintenance occupation

An exploration of teachers' understanding of their questioning practices in science lessons in early primary teaching in Thailand

PhD ThesisBased on social constructivist perspectives (Rojas-Drummond and Mercer, 2003), teachers’ questioning may have a direct impact on children’s learning and the development of children’s thinking. Most research into teachers’ questioning has been conducted in Western countries. However, in-depth qualitative research on teachers’ questioning practices in science classrooms in early primary education in Thailand is under-researched. Understanding teachers’ questioning practices will contribute to the improvement of teaching practices and teacher training programmes. This study aimed to explore Thai early primary teachers’ understanding of their questioning practices in terms of questioning purposes, question types and strategies, and to explain the factors that influence those classroom practices, in the context of science teaching in Thailand. A qualitative case study approach within the interpretivist paradigm was employed. Data were mainly gathered in the form of video recordings of classroom interaction, through videomediated interviews and relevant documents, such as lesson plans. This study is based on teacher reflections on questioning in which teachers identified some questions that they had asked. Through an inductive analysis of the data using template analysis, the current study found that teachers reported asking questions for a range of purposes in science teaching. Eleven such purposes were identified: gaining attention, checking if pupils can recall information, checking prior knowledge, checking understanding, enhancing knowledge, integrating with other topic areas, encouraging observation, hypothesizing, experimenting, building understanding, and encouraging pupils’ thinking. The finding shows that purposes relevant to hypothesizing, experimenting, and building understanding had a considerately higher proportion of open questions than closed ones. Another important finding was that eight categories of questioning strategies were employed by teachers in the classroom. The most commonly reported questioning strategy was repeating. It can be concluded that teachers’ understanding of questioning was closely in line with the concept of scaffolding assistance. This is because teachers reported that some purposes in asking questions assisted learning and were linked to the questioning strategies used. This research contributes to existing knowledge by providing a conceptual model of Thai teachers’ questioning practice in the science classroom. The proposed model is based on social constructivist theory, which is comprised of the three major elements of questioning purposes, ii question types, and strategies, and three layers of influencing factors: teacher cognition, cultural factors, and contextual factors.Suratthani Rajabhat Universit

Qualidade de vida e fatores associados à suspeição de transtornos mentais comuns em estudantes de Medicina em universidade de integração latino-americana

Tese apresentada à Escola de Enfermagem de Ribeirão Preto da Universidade de São Paulo, para obtenção do título de Doutor em Ciências, Programa de Pós-Graduação Enfermagem em Saúde Pública. Linha de pesquisa: Processo Saúde-Doença e Epidemiologia. Orientadora: Dra. Claudia Benedita dos SantosNesta tese, objetivou-se caracterizar o perfil, os fatores associados à suspeição de Transtornos Mentais Comuns (TMC) e a autopercepção da qualidade de vida (QV) nos estudantes do curso de Medicina da Universidade Federal da Integração Latino-Americana (UNILA). Foi realizado um estudo analítico transversal com 202 alunos brasileiros e estrangeiros latino-americanos. O questionário Perfil do Participante foi validado através do índice de validade de conteúdo (IVC) e aplicado nos alunos brasileiros e estrangeiros. Foram aplicados nos estudantes brasileiros o Self-Reporting Questionnaire-20 (SRQ-20) e o World Health Organization Questionnaire for Quality of Life – bref (WHOQoL-BREF) para avaliação da suspeição de TMC e da QV, respectivamente. Foram observadas diferenças estatisticamente significativas entre os grupos de alunos brasileiros e estrangeiros. As médias de idade (p = 0,006), da renda familiar (p = 0,002) e de horas por semana de atividade física (p < 0,0001) eram maiores nos brasileiros, assim como, foi encontrado menor número de pessoas que viviam com a renda familiar média (p = 0,002) e maior porcentagem de alunos que consideraram o autodesempenho acadêmico bom/excelente (p = 0,032) neste grupo. A condição de estar solteiro (p < 0,0001), ter religião (p = 0,007), nunca ter feito tratamento psiquiátrico/psicológico (p < 0,0001), sexo feminino (p = 0,041) e menor média da carga horária de sono diária (p < 0,0001) foram observadas em maior porcentagem nos estrangeiros. A prevalência de suspeição de TMC no grupo de estudantes brasileiros foi de 40% com IC95%: [0,31 ; 0,49]. Através da análise pela regressão logística, os domínios psicológico (p < 0,0001) e físico (p = 0,028) do WHOQoL-BREF, o período do curso (p = 0,039), a alimentação (p = 0,009) e achar o curso estressante (p = 0,034) foram associados à suspeição de presença de TMC no grupo de brasileiros. A partir dos resultados encontrados nesse trabalho, verifica-se a necessidade de pesquisas de causalidade de suspeição de TMC e de intensificar os conhecimentos, ampliar a prática de condutas no dia a dia e planejar ações a favor da saúde mental e saúde física do futuro médico.This thesis aimed to characterize the profile, the associated factors with suspicion of Common Mental Disorders (CMD) and the self-perception of quality of life (QoL) in Medicine students at the Federal University of Latin American Integration (UNILA). A cross-sectional analytical study was conducted with 202 Brazilian and foreign (latin american) students. The Participant Profile questionnaire was validated through the content validity index (CVI) and applied to Brazilian and foreign students. Self-Reporting Questionnaire-20 (SRQ-20) and World Health Organization Questionnaire for Quality of Life - bref (WHOQoL-BREF) were applied to Brazilian students to evaluate suspicion of CMD and QoL, respectively. Statistically significant differences were observed between groups of Brazilian and foreign students. The average age (p = 0.006), family income (p = 0.002) and hours per week of physical activity (p < 0.0001) were higher in Brazilians, and a lower number of people living with average family income (p = 0.002) and higher percentage of students who considered good / excellent academic self- performance (p = 0.032) in this group. The condition of being single (p < 0.0001), having religion (p = 0.007), never having received psychiatric / psychological treatment (p < 0.0001), female gender (p = 0.041) and lower average daily load of sleep (p < 0.0001) were observed in higher percentage in foreign students. The prevalence of suspected CMD in Brazilian students was 40% with 95% CI: [0.31 ; 0.49]. Through logistic regression analysis, the psychological (p < 0.0001) and physical (p = 0.028) domains of the WHOQoL-BREF, the course time (p = 0.039), the diet (p = 0.009) and finding the course stressful (p = 0.034) were associated with suspected presence of CMD in the group of Brazilians students. From the results found in this study, it is necessary to investigate causality of suspected CMD and to intensify knowledge, to expand the practice of daily conduct and to plan actions and to improve of mental health and physical health of the future Medicine doctorEsta tesis, tiene como objetivo caracterizar el perfil, los factores asociados a sospecha de presencia de Trastornos Mentales Comunes (TMC) y la autopercepción de calidad de vida (CV) en estudiantes del curso de Medicina de la Universidad Federal da Integración Latino- Americana (UNILA). Se realizó un estudio analítico transversal con 202 alumnos de nacionalidad brasilera y extranjera. El cuestionario Perfil de Participante se validó teniendo en cuenta el índice de validación de contenido (IVC) y se aplicó a alumnos brasileros y extranjeros. El Self-Reporting Questionnaire-20 (SRQ-20) y el World Health Organization Questionnaire for Quality of Life – bref (WHOQoL-BREF) se aplicó a estudiantes brasileros para evaluación de la sospecha de presencia de TMC y de la CV, respectivamente. Se observaron diferencias significativas estadísticamente entre los grupos de alumnos brasileros y extranjeros. El promedio de edad (p = 0,006), renta familiar (p = 0,002) y de horas por semana de actividad física (p < 0,0001) fueron mayores en los brasileros, como también, se encontró menor número de personas que vivían con renta familiar promedio (p = 0,002) y mayor porcentaje de estudiantes que consideraron el auto desempeño académico bueno/excelente (p = 0,032) en este grupo. La condición de estar soltero (p < 0,0001), profesar religión (p = 0,007), no realizar nunca tratamiento psiquiátrico/psicológico (p < 0,0001), sexo femenino (p = 0,041) y menor promedio de hora sueño por día (p < 0,0001) se observaron en un porcentaje mayor en extranjeros. La sospecha de presencia de TMC en el grupo de estudiantes brasileros fue de 40% con IC95%: [0,31 ; 0,49]. A través de análisis por la regresión logística, los dominios psicológicos (p < 0,0001) y físico (p = 0,028) de WHOQoL-BREF, el período de curso (p = 0,039), la alimentación (p = 0,009) y la consideración del curso como estresante (p = 0,034) se asociaron a sospecha de presencia de TMC en el grupo de brasileiros. A partir de los resultados obtenidos en esta investigación, se verifica la necesidad investigaciones de posibles TMC y estimular conocimientos, ampliar la práctica de conductas en el cotidiano, como también planificar acciones a favor de la salud mental y física del futuro médic

A Study of Rumsuad : Yadmit Sit Kru Klaew,Tambon Bangpid Amphur Lamngob Trat Province

The proposes of this research were to1. Study the history and culture of “Yadmit Sit Kru Klaew Rumsuad” folk play.2. Study the style of “Yadmit Sit Kru Klaew Rumsuad” folk play.The results were founded that1. “Rumsuad” folk play of Trat province was started in Ayutthaya period. It was developed fromSuad Phra Malai in the funeral. After that it was developed as Suad Kareuhat and became to “Rumsuad”folk play in the last night of the feneral. The objectives of “Rumsuad” folk play were to stay with thedeceased and reduce the sadness. “Yadmit Sit Kru Klaew Rumsuad” folk play is the old workgroup thatalso show the original style by use of a folk music. It differences from present time of Rumsuad thatchange the display to modern .2. The proponents’ clothing of çYadmit Sit Kru Klaew Rumsuadé folk play is black. The womanhave a colorful scarf on their neck. The instruments of “Rumsuad” folk play are Thon (drum) , Ching andGrap. They start with “WaiKhru” chapter, “Bok Ban” chapter, “Lamroung or Lamnok” chapter, themost popular chapter by using the Thai music rhythm and dance follow the songs from literature such asLaksanawong, SungThong, Phra Apaimanee etc. And before the dayspring, they will bring the case ofPhra Abhidhamma to “Suad Phra Malai” chapter and “Sung Ptet” chapter to send the deceased to theheaven at the last part.Key words: Rumsuad, Yadmit Sit Kru Klaew, history and culure, folk pla

A Comparison of Rhetorical Move Structures of Hotel, Restaurant, and Tourist Destination Homepages

The worldwide tourism industry in the era of globalization is marked with extremely fierce competition. It is crucial for hoteliers, restauranteurs, and tourist destination owners and operators to advertise their venues, products, and services effectively. A website is an important communication tool for hotel, restaurant, and tourist destination marketing organizations (Law &amp; Hsu, 2006; Law et al., 2010) to attract potential audiences and customers. The content onthe website, therefore, needs to be high quality and organized in the way that is most effective. This paper, therefore, aims to analyze the moves, and their structures, as well as the writing strategies used in each move in the content area ofpopular international hotel, restaurant, and tourist destination homepages, and to compare them across these three tourism products. Twenty four hotel homepages, twenty four restaurant homepages and twenty four tourist destinationhomepages from eight different countries were selected as the sample for analysis, employing the generic structure of advertisement proposed by Van der Vliet &amp; Redeker (2014) as the analysis framework. The main results revealedthat differences existed between the moves reported in the analysis framework and those found in each of the corpora in the present study. Homepages in each of the corpora also exhibited slight differences in terms of moves and theirstructures, pointing out variations that are caused by different types of products and services in the tourism industry. Moreover, the writing strategies found in each move were varied, yet they all helped to deliver their common communicative purposes

정확한 서열정렬기법과 인메모리 핵심 유전자 데이터베이스 기반의 향상된 메타유전체 분류법

학위논문 (박사) -- 서울대학교 대학원 : 자연과학대학 협동과정 생물정보학전공, 2020. 8. 천종식.샷건 메타지노믹스는 미생물과 숙주 또는 환경사이의 미치는 영향을 이해하는데 매우 중요한 역할을 하고 있다. 기술의 발달과 더불어 메타지노믹스를 통한 올바른 미생물 종의 동정과 각 종들의 분포는 마이크로바이옴 연구의 핵심 구성요소가 되었으며, 지난 10년간 샷건 메타지노믹스 분석을 위한 여러 알고리즘과 데이터베이스들이 개발되어져 왔다. 하지만 서로 다른 기준 데이터 혹은 알고리즘을 사용한 방법들은 서로 다른 분류 정보와 분석 파이프라인으로 인하여 편향된 결과를 나타내기도 하였는데, 이를 보완하고 보다 정확한 분류 동정을 위해 배양이 어려운 표준 균주와 같은 다양한 균주의 유전체 데이터를 포함하는 기준 데이터베이스의 중요성이 대두되고 있다. 샷건 메타지노믹스 분석에서 또 다른 중요한 요소는 분석에 소요되는 시간이라 할 수 있는데 대부분의 생물정보학적 프로그램들은 계산을 수행함에 있어 메모리와 알고리즘 최적화가 되어있지 않아 분석에 상당한 시간이 소요되는 문제점이 있다. 이러한 문제를 해결하기 위해, 본 연구에서는 exact match k-mer classification과 같은 방법을 사용하여 분석 속도를 향상시켰으며 Up-to-date Bacterial Core Gene (UBCG)를 기준 데이터베이스로 사용하여 보다 정확한 샷건 메타지노믹 분석을 수행할 수 있게 하였다. 분석의 효율성을 높이기 위해 두개의 기준 UBCG 데이터베이스가 만들어 졌으며 한 개는 박테리아의 분류체계에서 유효한 종명 (Valid names)만을 가지고 있는 데이터베이스와 다른 하나는 유효한 종명과 함께 EzBioCloud에 있는 genomospecies를 가지고 생성하였다. 검증을 위해 Streptococcus 종을 포함하는 (i) 합성된 메타지놈 샘플과 (ii) 만성 폐쇄성 폐질환(COPD) 환자의 임상 검체 (iii) 혈류 감염 환자의 임상 검체로 이루어진 세개의 데이터 셋을 이용하였으며 기존에 널리 알려진 샷것 파이프라인인 MetaPhlan2과 본 연구의 파이프라인을 비교 분석하였다. 위 검증 분석에서 UBCG를 기준 서열로 사용하기에 충분함을 검증하였으며, 빠르고 정확하게 기준 유전체에서 UBCG 서열을 뽑아 샷건 분석에 용이함을 증명하였다. 또한 genomospecies를 기준 데이터베이스에 추가함으로써, 보다 개선된 분류 정확도를 얻을 수 있음을 제시하였다. 마지막으로 비록 여러 파이프라인과 데이터베이스들이 존재하지만 보다 신뢰할 수 있는 분류결과를 얻기 위해선 기준 데이터베이스의 지속적인 업데이트와 분류 체계의 검증의 중요함을 강조하였다. 이후 본 연구에서 개발된 파이프라인을 이용하여 4,000개의 샷건 메타지놈 샘플에서 사람에 장내에 가장 많이 발견되는 Bacteroides 종에 대한 분석을 수행하였다. 많은 양의 데이터를 분석하여야 하기 때문에 기존에 많이 사용되는 MetaPhlAn2 과 같은 방법은 사용할 수 없었으며 분석 결과 Bacteroides는 도시화된 사람에게 많이 분포하는 반면 아프리카 혹은 남미지역에서 원시적 부족의 삶을 사는 사람에게서는 상대적으로 적게 분포함을 확인할 수 있었다. 또한 각 나라별 인구에서는 우점되는 Bacteroides 종이 다름을 확인할 수 있었는데 이는 각 연구의 샘플링 방법 혹은 위치에 따라 설명되어 질 수 있었다. 실험용 쥐의 결과에서는 가장 다양한 Bacteroides를 관찰할 수 있었으며 이는 많은 수의 기준 유전체가 생쥐에게서 나왔기 때문인 것으로 생각된다. 또한 고양이나 강아지 같은 반려동물의 샘플에서도 높은 상관관계를 발견할 수 있었는데 각 동물들의 생활양식과 먹이에 따른 결과인 것으로 보인다. 본 연구를 통해 보다 많은 메타지놈 데이터 분석의 필요성을 강조하고 있으며, 핵심 유전자들을 기준 데이터로 사용하는 방법의 실효성과 성능을 검증하였다. 이러한 핵심 유전자 기반의 기준 데이터베이스는 보다 정확하고 전체 미생물의 풍부도를 예측하는데 중요한 역할을 하는 것을 확인하였고 k-mer 방법을 통해 기존에 존재하던 다른 파이프라인 보다 더욱 빠른 결과를 도출할 수 있었다. 마지막으로 빠르게 기준 데이터베이스를 만들 수 있기 때문에 항상 최신의 데이터를 가지고 분석을 수행할 수 있으며 이는 궁극적으로 본 연구의 파이프라인을 실질적으로 연구나 진단 목적으로 이용하는 연구자들에게 큰 도움이 될 것이다.Shotgun metagenomics is of great importance to understand the microbial community composition of a sample and the impact it has on its host. The proper identification and quantification of bacterial species is a key component of any microbiome research that is based on metagenomic samples. In the last decade, several algorithms and databases have been developed, however the differences between references and the type of algorithm used for the classification makes the comparisons among themselves unfair and bias. The contents of the reference database, including genome sequences of type strains or reference genomes of uncultured species, have a great impact on the performance of the classification results of metagenomic samples. Another significant factor on shotgun metagenomics is the classification speed as most current bioinformatic tools lack computational and memory optimization. Here, I propose several enhancements to a well-known method, exact match k-mer classification in order to increase the overall speed of a metagenomic classification. This method was further improved by the use of Up-to-date Bacterial Core Gene (UBCG) sequences to provide better method for a faster and accurate shotgun metagenomic profiling classification. In order to prove the efficiency of our method, I built two UBCG-based reference databases: one containing UBCG sequences of valid named species, and the second one containing UBCG sequences of all valid named species and genomospecies in the EzBioCloud database. Three datasets containing Streptococcus species were used to evaluate the improved method against the MetaPhlan2 tool which is the most widely used open-source shotgun metagenomic classifier: (i) synthetic metagenomic samples, (ii) clinical sputum samples from patients with chronic obstructive pulmonary disease (COPD), and (iii) clinical samples of a blood stream infection. In this analysis, I demonstrated that UBCG sequences can be used as references for metagenomic classification, showing that they are easy to extract from genome sequences and accurate when predicting relative abundance. I also showed that the inclusion of genomospecies in the reference databases, significantly improves the classification accuracy of bacterial species within a metagenomic sample. Finally, I showed that while publicly available pipelines and databases are easily accessible, for accurate and reliable taxonomic classification, an updated database with proper taxonomic and genomic curation must be used. The method devised in this work is then applied to profile the Bacteroides species in over 4,000 shotgun metagenomic samples, which is one of most abundant members of the human gut microbiome. This task cannot be accomplished using conventional tools such as MetaPhlAn2 due to the high processing time they require. The results in this study showed that Bacteroides is high abundant in human samples from urban areas while being low abundant in humans from rural areas, particularly African and South American tribes. Countries showed dominance for a specific Bacteroides species, but this could also be explained by the type of study were the samples came from. Mice samples showed the most diversity of Bacteroides, this can be attributed by the number of bacterial references isolated from this organism. House cat and dog samples showed correlation between each other, this may be attributed to the similarities of their lifestyle and diet. This study shows the importance of having a great number of samples for any given metagenomic analysis, and even though, we have profiled thousands of samples, more might be needed in the future. The method proposed in this thesis demonstrates that core genes are reliable reference sequences for shotgun metagenomics. Their implementation as reference sequences in metagenomic databases improves the accuracy of the abundance prediction of any given sample. Additionally, with the use of a k-mer approach, this methods running time outperforms the most popular shotgun metagenomic tools. The work presented in this thesis aims to help microbial research by providing faster and accurate metagenomic taxonomic predictions. Finally, with the ability of updating a metagenomic database with ease, will help researchers to obtain the most up-to-date results to find potential diagnosis or treatments for diseases associated to human microbial communities.Chapter 1. General Introduction 1 1.1. Introduction to metagenomics 2 1.2. 16S rRNA sequencing 3 1.3. Shotgun metagenomic sequencing 5 1.3.1. History 5 1.3.2. Sample extraction 7 1.3.3. Library preparation 8 1.3.4. Sequencing 8 1.4. Shotgun metagenomic classification 9 1.4.1. Homology-based approaches 9 1.4.2. Exact match K-mer approaches 11 Chapter 2. An exact match k-mer algorithm 13 2.1. An exact match k-mer classification approach 14 2.1.1. Definition of the problem 14 2.1.2. Building a k-mer reference database 14 2.1.2.1. K-mer counting 14 2.1.2.2. K-mer mapping 16 2.1.3. Classification of a metagenomic read 16 2.1.3.1. K-mer search 19 2.1.3.2. Scoring a metagenomic read 20 2.1.4. Calculating the metagenome profile 20 2.1.4.1. Normalization for LCA-assigned reads 21 2.1.4.2. Normalization for cell count relative abundance 22 2.2. RAM memory usage 22 2.3. Quality Control 23 2.3.1. Read Trimming 23 2.3.2. Host read removal 24 Chapter 3. Revealing unrecognized species in the genus Streptococcus 28 3.1. A brief history of streptococcus in clinical metagenomics 29 3.2. Results and Discussion 32 3.2.1. Building a core gene reference database 32 3.2.2. Evaluation of Pipelines using Synthetic Metagenomes 36 3.2.3. Chronic obstructive pulmonary disease samples 44 3.2.3. Evaluating the value of genomospecies references in a metagenomic database 56 3.2.4. Identifying accurately a Streptococcal infection using clinical data 63 3.2.5. Effects of different ANI thresholds on the classification of genomospecies 69 3.3. Materials and Methods 76 3.3.1. Selecting the reference genomes 76 3.3.2. Average nucleotide identity and hierarchical clustering 76 3.3.3. Synthetic and Real metagenomic samples 77 3.3.4. Extracting the core genes 77 3.3.5. Taxonomic profiling 83 3.3.6. Biomarker discovery 84 3.4. Conclusions 85 Chapter 4. A large-scale shotgun metagenomic analysis on Bacteroides 86 4.1. Introduction 87 4.2. Bacteroides on the human gut 89 4.2.1. Collecting the samples 89 4.2.2. Methods 89 4.2.2.1. Reference Genomes 89 4.2.2.2. Metagenome profiling 90 4.2.3. Results 103 4.3. Bacteroides on Animal Species 128 4.3.1. Methods 128 4.3.2. Results 128 4.4. Discussion and conclusions 133 General Conclusion 135 References 139 Appendix I. A list of genomes from the genus Streptococcus used on Chapters 3 analysis. 146 국문초록 155Docto