Livet som sjöbefäl är i dagens samhälle ofta förknippat med en världsomspännande arbetsplats med goda arbetsförhållanden. Dessa förhållanden under vilka svenska sjöbefäl idag arbetar kan dock snabbt förändras under en världspandemi, då många länder världen över stänger sina gränser och försätter landet i isolation. Men till vilken grad har covid-19-pandemin påverkat svenska sjöbefäl i dess yrkesliv och privat? Med den frågeställningen som bakgrund är syftet med den här studien att undersöka och belysa hur de svenska sjöbefälen anser sig påverkats och vad som kan förbättras inför framtiden.                                                                           Genom kvalitativa, semistrukturerade intervjuer med 5 olika svenska sjöbefäl har den empiri som ligger till grund för resultatet samlats in. Resultatet visar bland annat att en absolut majoritet av de respondenter som medverkat i studien upplever att deras familjer i störst utsträckning påverkats och att detta faktum var den jobbigaste delen av att inte vara hemma under betydligt längre tidsperioder än vad dessa befäl vanligtvis är. Informanterna önskar se förändringar kring deras möjligheter till att mönstra av och på i framtiden. / The life as a merchant marine officer is often seen as a worldwide workplace with good working and living standards. However, the life standard onboard these vessels where the Swedish officers work can quickly change during a worldwide pandemic when a lot of countries close their borders and put themselves in isolation. So, to what degree are these officers private life and life onboard affected by the corona pandemic?                                                                                                                     With that questions as background the purpose of this thesis is to research how the world pandemic affected the Swedish marine officers as well as what they think needs to be changed in future. Through interviews with 5 different Swedish officers using a semi-structured way of interviewing, data answering these questions has been collected. The result of this research shows amongst other that an absolute majority of the officers that were interviewed found the family and relatives to be the toughest subject. They also point it out as the most affected part of their lives, mostly because of the long periods they all spent onboard their vessels. All the officers answered that they wanted to see some changes in the future when it comes to their sign on and sign off possibilities.

Rather than being randomly wired together, the components of complex network systems are recently reported to represent a scale-free architecture, in which the node degree distribution follows power-law. While social networks are scale-free, it is natural to utilize their structural properties in some social network applications. As a result, this dissertation explores social network architectures, and in turn, leverages these architectures to facilitate some influence and information propagation applications. Social network architectures are analyzed in two different aspects. The first aspect focuses on the node degree snowballing effects (i.e., degree growth effects) in social networks, which is based on an age-sensitive preferential attachment model. The impact of the initial links is explored, in terms of accelerating the node degree snowballing effects. The second aspect focuses on Nested Scale-Free Architectures (NSFAs) for social networks. The scale-free architecture is a classic concept, which means that the node degree distribution follows the power-law distribution. `Nested' indicates that the scale-free architecture is preserved when low-degree nodes and their associated connections are iteratively removed. NSFA has a bounded hierarchy. Based on the social network structure, this dissertation explores two influence propagation applications for the Social Influence Maximization Problem (SIMP). The first application is a friend recommendation strategy with the perspective of social influence maximization. For the system provider, the objective is to recommend a fixed number of new friends to a given user, such that the given user can maximize his/her social influence through making new friends. This problem is proved to be NP-hard by reduction from the SIMP. A greedy friend recommendation algorithm with an approximation ratio of $1-e^{-1}$ is proposed. The second application studies the SIMP with the crowd influence, which is NP-hard, monotone, non-submodular, and inapproximable in general graphs. However, since user connections in Online Social Networks (OSNs) are not random, approximations can be obtained by leveraging the structural properties of OSNs. The modularity, denoted by $\Delta$, is proposed to measure to what degree this problem violates the submodularity. Two approximation algorithms are proposed with ratios of $\frac{1}{\Delta+2}$ and $1-e^{-1/(\Delta+1)}$, respectively. Beside the influence propagation applications, this dissertation further explores three different information propagation applications. The first application is a social network quarantine strategy, which can eliminate epidemic outbreaks with minimal isolation costs. This problem is NP-hard. An approximation algorithm with a ratio of 2 is proposed through utilizing the problem properties of feasibility and minimality. The second application is a rating prediction scheme, called DynFluid, based on the fluid dynamics. DynFluid analogizes the rating reference among the users in OSNs to the fluid flow among containers. The third application is an information cascade prediction framework: given the social current cascade and social topology, the number of propagated users at a future time slot is predicted. To reduce prediction time complexities, the spatiotemporal cascade information (a larger size of data) is decomposed to user characteristics (a smaller size of data) for subsequent predictions. All these three applications are based on the social network structure. / Computer and Information Science

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Made available in DSpace on 2014-10-09T12:40:59Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:57:32Z (GMT). No. of bitstreams: 1 04015.pdf: 1118706 bytes, checksum: cfb96bf2d7bcbe122082fa953b52e435 (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Made available in DSpace on 2014-08-20T13:44:28Z (GMT). No. of bitstreams: 1 dissertacao_loraine_rodrigues_jardim.pdf: 1137522 bytes, checksum: de7cff66f6911caeea51266527680966 (MD5) Previous issue date: 2012-08-13 / The occurrence of invasive plants can alter crop yields, because these plants often grow so strong, competing for light, water and nutrients, affecting seed production. The taxonomic identification of these species is the first step in planning a control program. The objectives of this work are: develop and validate a computer system to support the identification of units spread of invasive species; differentiate seeds of three species of quarantine pests Amaranthus genus of three species of the same genus harmful tolerated by analyzing the morphology inside and outside of their seeds. This work is organized into two chapters: Chapter 1 - describes the process of building a computer system to support the identification of units spread of invasive species. The database of the computer system was composed of morphological descriptions, drawings and photographs of the morphological structures of 198 seeds of invasive species. We developed a tool (available on the Web) to use the database built, providing morphological search by entering information on the morphology of seed and/or dispersion unit that seeks to identify the user. We conducted a test system functionality, which consisted of a questionnaire assessment while using the system. The system proved effective in identifying species, aiding the identification of invasive species. The creation of the database with the information and proposed structure meets the demand of the identification system. Chapter 2 - presents the morphological differentiation of the seeds of six species of the genus Amaranthus, seeking to differentiate species of harmful species quarantine pests in Brazil. We analyzed morphological descriptions of six species of the genus Amaranthus produced and a dichotomous key to highlight morphological able to differentiate species. The visualization of the structure of the embryo by slitting the seed, allows to differentiate the species of Amaranthus. Detailed analysis of the morphological internal and external seeds of Amaranthus is effective in the identification and differentiation of species. / A ocorrência de plantas invasoras pode alterar o rendimento das culturas, pois estas plantas frequentemente crescem de maneira robusta, competindo por luz, água e nutrientes, afetando a produção de sementes. A identificação taxonômica destas espécies é o primeiro passo no planejamento de um programa de controle. Os objetivos deste trabalho são: desenvolver e validar um sistema computacional de apoio à identificação de unidades de dispersão de espécies invasoras; diferenciar sementes de três espécies de pragas quarentenárias do gênero Amaranthus de três espécies nocivas toleradas do mesmo gênero, através da análise da morfologia interna e externa das suas sementes. Este trabalho está organizado em dois capítulos: Capítulo 1- descreve o processo de construção de um sistema computacional para apoio à identificação de unidades de dispersão de espécies invasoras. O banco de dados do sistema computacional foi composto por descrições morfológicas, desenhos das estruturas morfológicas e fotografias de 198 sementes de espécies invasoras. Foi desenvolvida uma ferramenta (disponibilizada na Web) para utilizar o banco de dados construído, oferecendo busca por características morfológicas, através da inserção de informações da morfologia da semente e/ou unidade de dispersão que o usuário procura identificar. Realizou-se um teste de funcionalidade do sistema, que consistiu na aplicação de questionário de avaliação durante a utilização do sistema. O sistema mostrou-se eficaz na identificação de espécies, auxiliando a identificação de espécies invasoras. A criação do banco de dados com as informações e a estrutura propostas atende a demanda do sistema de identificação. Capítulo 2- apresenta a diferenciação morfológica das sementes de seis espécies do gênero Amaranthus, em busca de diferenciar espécies nocivas de espécies pragas quarentenárias no Brasil. Foram analisadas descrições morfológicas de seis espécies do gênero Amaranthus e elaborada uma chave dicotômica para destacar características morfológicas capazes de diferenciar as espécies. A visualização da estrutura do embrião, mediante corte longitudinal da semente, permite diferenciar as espécies de Amaranthus. A análise detalhada das características morfológicas internas e externas das sementes de Amaranthus é eficaz na identificação e diferenciação das espécies.

The rapidly spreading pandemic of SARS-CoV-2 (COVID-19) infection with high morbidity and mortality has overwhelmed the global healthcare services. With mysterious origins and the capacity of affecting multiple types of tissues, SARS-CoV-2 has baffled many scientists - which has posed great challenges in the development of pharmaceutical treatments and preventions (i.e., vaccination). The COVID-19 pandemic has also led to a slew of non-pharmaceutical interventions (NPIs) to slow down the spread of the virus. The sudden imposition of these NPIs including social distancing, lock-down, school closures, isolation, and quarantine of suspected cases or contacts, has greatly affected the mental health of children and adolescents. Concerns about the impact of these NPIs on mental health, especially for vulnerable populations such as children and adolescents, have emerged. This study discusses several different aspects of the impact of the COVID-19 pandemic on the mental health of children and adolescents.Accumulating evidence has shown that the vast majority of children and adolescents exposed to the SARS-CoV-2 virus are asymptomatic, although few cases turned unfortunately severely ill. The genomics, microbiology, and biochemistry of this novel coronavirus reveal several peculiarities, making it a tough entity. The profound impact of social distancing along with the closure of schools, parks, and other recreational activities on the delicate minds of children and adolescents makes them irritable, angry, and rebellious. This assumes a major challenge in children with mental health issues or in those with special needs. Lock-down, quarantine and isolation further complicate the mental health issues and are discussed along with remedial measures. The impact of an already overwhelmed medical care system on the mental healthcare quality can be profound and needs a specially chartered approach by the psychiatrists supplementing the COVID-19 control activities. Children/adolescents with neuropsychiatric issues need special care, as they have abnormal impulsive behaviour and actions such as running away, unhygienic acts, spitting etc. All these mental health issues in children and adolescents, who form a sizable population of the society and are the future of the planet, forms the subject matter of this work. Thus, all programmes of COVID-19 control must simultaneously address these important mental health issues of children and adolescents to prevent this ‘parallel pandemic’ of psychiatric disorders. The latter may persist much longer and prove equally challenging and costly.

Introducción: Desde el inicio de la pandemia por el nuevo coronavirus, a nivel mundial se han adoptado diversas medidas para disminuir la propagación de este. Entre ellas, el aislamiento social obligatorio, el cual ha generado cambios en el estilo de vida de las personas, especialmente en los niños preescolares, quienes han visto interrumpidas, y sustituidas sus actividades académicas a modalidades online, limitando sus actividades recreacionales por actividades más sedentarias. Sumado a esto, el Perú ya venía experimentando un aumento en el consumo de productos ultraprocesados, con incremento en la prevalencia de sobrepeso y obesidad en niños. Objetivo: Explorar cómo influye la evolución de la pandemia del COVID-19 en la elección de los productos ultraprocesados que realizan las madres para la alimentación del niño preescolar. Método: Estudio cualitativo con enfoque fenomenológico. Se realizó 26 entrevistas semiestructuradas utilizando una guía de preguntas. La muestra seleccionada fue por bola de nieve hasta alcanzar la saturación. Resultados: Las madres entrevistadas tuvieron entre 21 y 47 años de edad, la mayoría vivía en los distritos de Miraflores y Surco, contaban con estudios superiores completos y trabajo al momento de las entrevistas. Ellas expresaron que la experiencia de vivir la evolución de la pandemia ha generado cambios en la dinámica de sus familias como: alteraciones en los horarios, introducción del trabajo remoto, adaptación de sus hijos a la educación virtual y mayor sedentarismo. Se demostró que la mayoría tenía un adecuado conocimiento respecto a los productos ultraprocesados. Sin embargo, se evidenció una mayor elección de estos para los preescolares, siendo estos consumidos mayormente en las tardes. Conclusión: Los cambios generados por la evolución de la pandemia aumentaron la elección de productos ultraprocesados por parte de las madres de los niños preescolares. / Introduction: Since the beginning of the new coronavirus pandemic, measures have been taken worldwide to reduce its spreading. Among them, obligatory quarantine, which has generated changes in people’s lifestyles, especially that of preschool aged children, who have been forced to substitute their academic activities for online modalities and their recreational activities for more sedentary ones. In addition, Peru has been experiencing an increase in the consumption of ultra-processed products and in the prevalence of overweight and obesity in children. Objective: Explore how the evolution of the COVID-19 pandemic influences the choice of ultra-processed products that mothers make for feeding their preschool children. Methods: Qualitative study with a phenomenological approach. Twenty-six semi-structured interviews were conducted using a question guide. The sample was selected by snowball until reaching saturation. Results: The interviewed mothers were between 21 and 47 years old, the majority lived in the districts of Miraflores and Surco, had completed higher education and they had work at the time of the interviews. They expressed that the experience of living the evolution of the pandemic has generated changes in the dynamics of their families such as: alterations in schedules, introduction of remote work, adaptation of their children to virtual education and greater sedentary lifestyle. Most were shown to have adequate knowledge of ultra-processed products. However, a greater choice of these was evidenced for preschoolers, being these consumed mostly in the afternoons. Conclusion: The changes generated by the evolution of the pandemic increased the choice of ultra-processed products by the mothers of preschool children. / Tesis

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I slutet av 2019 upptäcktes ett nytt coronavirus vars framfart klassades som en pandemi av WHO i mars 2020. Sjukdomen som följer på viruset, covid-19, har i Sverige klassats som samhällsfarlig sjukdom vilket inneburit att myndigheterna kunnat vidta extraordinära skyddsåtgärder. I april 2020 infördes i Sverige särskilda rekommendationer riktade till äldre som innebar en uppmuntran till frivillig karantän. Med vetskap från tidigare studier om att många uppgett att denna karantän resulterat i sämre psykiskt mående och stor oro frågar sig den här studien vilka faktorer som ligger till grund för denna oro. Studien använder sig av befintliga fritextsvar från en redan genomförd enkät. Genom att jämföra resultaten med en teori om psykologisk resiliens av John Reich framkommer att många av de äldre oroar sig på grund av bristande information, på grund av en känsla av förlorad kontroll och på grund av en stor saknad efter socialt umgänge. Vidare känner sig många hopslagna som en enda stor riskgrupp vilket gör att de har svårare att acceptera myndigheters beslut. Genom att segmentera den grupp som skall nås av risk- och kriskommunikation och genom att motivera myndigheternas beslut ökar man det psykologiska välbefinnandet i gruppen samtidigt som följsamheten troligen ökar. / At the end of 2019, a new coronavirus made its appearance and in March 2020 it was classified as a pandemic by the World Health Organization (WHO). In Sweden, the disease following infection by the virus, COVID-19, has been classified as a danger to society which have allowed the authorities to apply extraordinary measures. In April 2020, the elderly was encouraged to stay in voluntary quarantine. Knowing from earlier studies that this quarantine has resulted in deteriorating psychological well-being and great anxiety, this paper seeks to understand what factors might be contributing to this anxiety. By studying existing text answers from previous studies and analysing them with regards to a theory of psychological resilience by John Reich, results indicate that increased anxiety stems from lack of information, loss of control and a great longing for social contact. Furthermore, many of the respondents feel wrongfully lumped together in a risk category which makes it harder for them to accept decisions made by the authorities. By segmenting the group that is target for risk and crisis communication, and by giving the grounds for decisions taken by the authorities, psychological well-being and compliance to recommendations would probably be increased.

Objetivo: Asociar el uso del servicio dental y la necesidad de tratamiento en residentes de Lima, Perú durante el aislamiento social obligatorio por la COVID-19 en el año 2020. Métodos: Estudio observacional, analítico y transversal. La muestra fue conformada por 223 residentes mayores de edad que cumplieron con los criterios de inclusión. Se tomó como base encuestas nacionales de autoreporte para seleccionar preguntas relacionadas a las variables uso del servicio dental, necesidad de tratamiento y covariables como sexo, ocupación, grado de instrucción, distrito de residencia, edad, ingreso económico y seguro de salud. Se realizó un análisis descriptivo mediante frecuencias absolutas y relativas, un análisis bivariado mediante la prueba de chi cuadrado y un análisis multivariado utilizando la regresión de Poisson con varianza robusta donde se reportaron razones de prevalencias crudas y ajustadas. Resultados: El 58.3% de los encuestados no hicieron uso del servicio dental durante el aislamiento social obligatorio a pesar de necesitar atención, siendo el principal motivo de inasistencia la pandemia por la COVID-19 (37.67%). Además, se registró que la urgencia (24,66%) fue la necesidad de tratamiento más predominante. No se halló asociación estadísticamente significativa entre el uso del servicio dental y la necesidad de tratamiento Conclusión: Las personas a pesar de tener una necesidad de tratamiento, no necesariamente utilizaron los servicios dentales durante el periodo de aislamiento social obligatorio en el Perú durante el año 2020. / Objective: To associate the use of dental services and the need for treatment in patients in Lima, Peru during social isolation mandated by COVID-19 in the year 2020. Methods: Observational, analytical and cross-sectional study. The sample consisted of 223 residents who met the inclusion criteria. National self-report surveys were used as a basis for selecting questions related to the variables use of dental services, treatment need and covariates as sex, occupation, level of education, district of residence, age, income and health insurance. A descriptive analysis was carried out using absolute and relative frequencies, a bivariate analysis using the chi-square test and a multivariate analysis using Poisson regression with robust variance where crude and adjusted prevalence ratios were reported. Results: 58.3% of the respondents didn’t make use of the dental service during the mandatory social isolation despite needing care, the main reason for non-attendance being the COVID-19 pandemic (37.67%). In addition, it was recorded that urgency (24.66%) was the most predominant need for treatment. No statistically significant association was found between the use of dental services and the need for treatment. Conclusion: Patients, despite having a need for treatment, did not necessarily use dental services during the period of compulsory social isolation in Peru in the year 2020. / Tesis