abstract: The study of bacterial resistance to antimicrobial peptides (AMPs) is a significant area of interest as these peptides have the potential to be developed into alternative drug therapies to combat microbial pathogens. AMPs represent a class of host-mediated factors that function to prevent microbial infection of their host and serve as a first line of defense. To date, over 1,000 AMPs of various natures have been predicted or experimentally characterized. Their potent bactericidal activities and broad-based target repertoire make them a promising next-generation pharmaceutical therapy to combat bacterial pathogens. It is important to understand the molecular mechanisms, both genetic and physiological, that bacteria employ to circumvent the bactericidal activities of AMPs. These understandings will allow researchers to overcome challenges posed with the development of new drug therapies; as well as identify, at a fundamental level, how bacteria are able to adapt and survive within varied host environments. Here, results are presented from the first reported large scale, systematic screen in which the Keio collection of ~4,000 Escherichia coli deletion mutants were challenged against physiologically significant AMPs to identify genes required for resistance. Less than 3% of the total number of genes on the E. coli chromosome was determined to contribute to bacterial resistance to at least one AMP analyzed in the screen. Further, the screen implicated a single cellular component (enterobacterial common antigen, ECA) and a single transporter system (twin-arginine transporter, Tat) as being required for resistance to each AMP class. Using antimicrobial resistance as a tool to identify novel genetic mechanisms, subsequent analyses were able to identify a two-component system, CpxR/CpxA, as a global regulator in bacterial resistance to AMPs. Multiple previously characterized CpxR/A members, as well as members found in this study, were identified in the screen. Notably, CpxR/A was found to transcriptionally regulate the gene cluster responsible for the biosynthesis of the ECA. Thus, a novel genetic mechanism was uncovered that directly correlates with a physiologically significant cellular component that appears to globally contribute to bacterial resistance to AMPs. / Dissertation/Thesis / Ph.D. Molecular and Cellular Biology 2013

abstract: The widespread adoption of mobile devices gives rise to new opportunities and challenges for authentication mechanisms. Many traditional authentication mechanisms become unsuitable for smart devices. For example, while password is widely used on computers as user identity authentication, inputting password on small smartphone screen is error-prone and not convenient. In the meantime, there are emerging demands for new types of authentication. Proximity authentication is an example, which is not needed for computers but quite necessary for smart devices. These challenges motivate me to study and develop novel authentication mechanisms specific for smart devices. In this dissertation, I am interested in the special authentication demands of smart devices and about to satisfy the demands. First, I study how the features of smart devices affect user identity authentications. For identity authentication domain, I aim to design a continuous, forge-resistant authentication mechanism that does not interrupt user-device interactions. I propose a mechanism that authenticates user identity based on the user's finger movement patterns. Next, I study a smart-device-specific authentication, proximity authentication, which authenticates whether two devices are in close proximity. For prox- imity authentication domain, I aim to design a user-friendly authentication mechanism that can defend against relay attacks. In addition, I restrict the authenticated distance to the scale of near field, i.e., a few centimeters. My first design utilizes a user's coherent two-finger movement on smart device screen to restrict the distance. To achieve a fully-automated system, I explore acoustic communications and propose a novel near field authentication system. / Dissertation/Thesis / Doctoral Dissertation Computer Science 2014

O estudo busca esclarecer pontos essenciais sobre o emprego da termocromia em têxteis por meio de sua aplicação em estampas em camisetas, respondendo questões sobre o poder expressivo destas e do uso da termocromia como recurso de qualificação em projetos de Design de Superfície. A pesquisa traz dados históricos da camiseta como objeto de design e moda. Nesse contexto verificou-se a relevância dos esclarecimentos técnicos sobre o funcionamento da tinta termocrômica, assim como apresenta-se no estudo uma gama de produtos que se utilizaram da aplicação desta técnica, além de estudos acadêmicos considerados inovadores nessa área de conhecimento. O objetivo principal do estudo é explorar novos conhecimentos sobre os sistemas e técnicas em relação à aplicabilidade da termocromia em estampas de camisetas, bem como mostrar as capacidades subjetivas de comunicação/expressão e de interatividade em produtos com essa tecnologia, que podem servir como auxílio para os designers em projetos inovadores. Neste sentido, foram propostos estudos experimentais de aplicação de estampas com tinta termocrômica em camisetas, que deram o sentido fundamental a esta dissertação, acrescentando conhecimento e abrindo espaço para novas pesquisas no âmbito interdisciplinar. Neste estudo de caso exploratório, foi possível concluir, que os métodos mostrados aqui são fatores importantes de inovação para o setor têxtil e de moda e que os testes produzidos provaram a necessidade de rigor técnico contido nas especificações técnicas do fornecedor. / This study aims to clarify some fundamental questions related to textile thermochromism in the application of t-shirt printing, namely the expressive power of prints and the use of thermochromism as a resource in surface design. The investigation brings historical data regarding the t-shirt as an object of design and fashion. In this context, the importance of technical clarification related to the performance of thermochromic ink is verified and a range of products utilized in this technique are presented. A number of innovative academic studies in this area are also presented. The main objectives of this study are to investigate new knowledge about the applicability of systems and techniques utilized in thermochromic t-shirt graphics and to demonstrate the subjective capacity of expression and interaction of products that utilize this technology, which can serve as an aid to designers in innovative projects. From this perspective, experimental tests in the application of thermochromic t-shirt printing were proposed, providing significance to this thesis, enhancing the knowledge in this field and promoting further interdisciplinary research. In this exploratory case study it was possible to conclude that the methods shown here represent important innovations in the textile and fashion sectors and that the tests demonstrated the necessity of technical rigor regarding manufacturers’ technical specifications.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-06-13T13:30:01Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação-Renato-biblioteca_final.pdf: 2729606 bytes, checksum: 301e75026662b18d7b50c48803cdf2a6 (MD5) / Made available in DSpace on 2016-06-13T13:30:02Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação-Renato-biblioteca_final.pdf: 2729606 bytes, checksum: 301e75026662b18d7b50c48803cdf2a6 (MD5) Previous issue date: 2014-12-18 / A popularização da TV Digital no mundo trouxe consigo melhorias para o telespectador como, imagem e som em alta definição, multiprogramação, mobilidade e acesso à Internet. Este crescimento coincidiu com a popularização dos dispositivos móveis inteligentes, smartphones e tablets, habilitando aos telespectadores à busca e visualização de conteúdos diversos ao mesmo tempo que assiste a esta programação. O uso destes aparelhos móveis enquanto se assiste a TV gerou o conceito de Segunda Tela. No entanto, o conteúdo adquirido nem sempre possui ligação com o programa que está sendo transmitido pela emissora de TV, tornando este tipo de tecnologia um concorrente ou uma alternativa à programação transmitida, dispersando a atenção do telespectador. Um dos grandes desafios é encontrar ferramentas computacionais mais eficientes para a elaboração e implementação de formas de disponibilização de conteúdos complementares ao transmitido pela TV, e ao mesmo tempo torná-las interessantes e atrativas aos olhos dos usuários. Este trabalho propõe um modelo para o desenvolvimento de aplicativos para TV Digital que utiliza informações contextuais da programação da TV, da própria TV e do dispositivo de Segunda Tela para que, de forma automática e simples, seja possível a exibição de conteúdos Web complementar à programação corrente da TV de forma síncrona. Utilizando estruturas de comunicação atualmente em uso pelas emissoras e definidas através de padrões regulamentados, o trabalho desenvolvido propõe uma abordagem plausível de implantação, demonstrando que é possível prover conteúdos complementares Web ao telespectador, de forma simples, automática e síncrona, tornando a experiência de assistir televisão ainda mais rica e completa. / The popularization of digital TV in the world has brought improvements to the viewer as, image and sound in high definition, multiprogramming, mobility and Internet access. This increase coincided with the popularity of smart mobile devices, smartphones and tablets, enabling viewers to search and display various types of content while watching TV. The use of mobile devices while watching TV created the concept of Second Screen. However, the mobile content does not always have connection with the program being broadcast on TV, making this type of technology a competitor or an alternative to broadcast programming, scattering the viewer's attention. A major challenge is to find more efficient computational tools for designing and implementing ways of providing additional content to broadcast on TV, and at the same time make them interesting and attractive in the eyes of users. This paper proposes a model for the development of applications for Digital TV that uses contextual information of TV scheduling and the second screen device. So it may be possible in an automatically and simple way to display web content related to the TV schedule synchronously. Using the current communication structures by broadcasters and defined through regulated standards, the developed work proposes a plausible approach to implementation, demonstrating that it is possible to provide additional web content to viewer, in a simple way, automatic and synchronously, making the experience of watch TV even more rich and full.

Com a popularização dos dispositivos móveis, mais e mais pessoas assistem aos programas de televisão enquanto usam essas plataformas para acessar a web, em busca de informações sobre a atração e para compartilhar opiniões em redes sociais e sites onde a atração está em evidência. A pesquisa aqui apresentada reflete sobre como a convergência entre várias telas interfere na produção de sentido das mensagens apreendidas e na experiência de comunicação, especificamente no caso dos espectadores que assistem aos programas enquanto interagem nas redes sociais digitais Twitter e Facebook. Mais do que isso, quer entender como o jornalismo se posiciona quanto à esse uso simultâneo, aproveitando a seu favor ou não essa duplicidade de fontes de informação. Foram analisadas quatro editorias - esportes, entretenimento, política e cotidiano, por meio da cobertura jornalística de eventos de diferentes proporções e padrões de relevância (nacional e internacional). Os recortes de estudo da dissertação são o Carnaval 2013 - desfile das escolas de samba do grupo especial de São Paulo/SP e Rio de Janeiro/RJ e apresentações de trios elétricos em Salvador, Copa das Confederações FIFA 2013, notícias de três noticiários nacionais (Jornal Hoje, Jornal Nacional e Jornal da Cultura em abril/2014) e cobertura do Jornal da Cultura, Jornal Nacional, Jornal Hoje e Jornal da Globo sobre a votação do Marco Civil da Internet pelo Congresso Nacional brasileiro (março/2014). Em todos os casos analisados, a segunda tela é pouco explorada ou ignorada pela TV. A dificuldade não está na editoria, ao passo que foram analisadas desde específicas - como política e esportes - até geral. Também não é o tamanho do evento, considerando a Copa das Confederações FIFA 2013 que atrai a atenção mundial. A emissora de televisão tão pouco significa muito nesse processo de inaptidão social digital. A limitação está no papel que os comunicadores atribuem à Tecnologia da Informação e Comunicação, priorizando a expansão do alcance das mensagens e não a usando como aliada para a renovação da proposta narrativa de noticiários que serão consumidos na companhia de telas secundárias. / With the popularization of mobile devices, more and more people watch the television programs while using these platforms to access the web, functioning as the second screen in the search for information about the attraction and opinions to share on social networks and websites where the attraction is in evidence. The research presented here reflects on how this convergence of multiple screens interferes with the production of meaning of messages and communication experience, with the focus the viewers while watching programs that are interacting in digital social networks Twitter and Facebook. More than that, how journalism understands that concurrent use, taking advantage of their favor or not the duplicity of information sources. Sports, entertainment, politics and everyday - a few days of news coverage of events in different proportions, patterns of national and international relevance, and four editors were analyzed. Comprise the study analysis of the 2013 Mardi Gras - parade of samba schools of São Paulo / SP and Rio de Janeiro / RJ and presentations of electric trucks in Salvador, FIFA Confederations Cup 2013 news from three national newscasts (Journal Today National Journal and Journal of Culture in abril/2014) and news coverage of the Journal of Culture, National Journal and Journal of the globe on the vote of the Civil Framework Internet by the Brazilian National Congress (março/2014). In all cases analyzed, the second screen is little explored or ignored by television. The difficulty is not in publishing, while we analyze specific long as politics and sports, to general. Nor is it the size of the event, considering the Confederations Cup, which attracts worldwide attention. The television station also involved does not mean much in the digital social awkwardness process. The limitation lies in the role that communicators attach to Information Technology and Communication, using the priority to support expansion of the message and not as allies to the proposed renewal of the narrative of newscasts that will be consumed in the company of secondary screens.

Nas exposições, galerias de arte, espaço urbano, observamos atualmente a presença de numerosas obras de imagens em movimento projetadas. Estas obras se utilizam em sua construção do dispositivo cinema: projeção, tela, espaço escuro, filmes, mas produzem alterações na forma padrão dominante de apresentação associada a esse dispositivo: espectador sentado, duração imposta de observação de aproximadamente 1 a 2 horas, sala escura, projeção única e frontal sobre uma única tela, apresentada em uma sala com a arquitetura semelhante à do teatro italiano. A presente pesquisa destina-se a estudar a migração de imagens e do dispositivo cinema, para os espaços de arte e as alterações que estão sendo feitas com esse dispositivo. Essas alterações embora mais intensas atualmente, não são inéditas. Observaremos as modificações realizadas nesse dispositivo e focaremos na tela, através do estudo desse elemento. Para isso, faremos um breve histórico dela, análises e descrições de várias obras, que façam uso da tela de forma diferenciada do padrão, alterando sua quantidade, disposição no espaço, formato e materialidade. / Exhibitions, art galleries, urban space, today observed the presence of numerous works of projected images in motion. These works are used in its construction of cinema device: projection screen, dark space, movies, but produce changes in the dominant standard form of presentation associated with this device: spectator sitting, imposed duration of observation of approximately 1 to 2 hours, dark room , and single front projection on a single screen, displayed in a room similar to the Italian theater architecture. This research intended to study the migration of images and movie device for art spaces and the changes that are being made with this device. These changes although more intense now, are not unprecedented. Observe the changes made to the device, and will focus on the screen, through the study of this element. For this, we will make a brief history of it, analyzes and descriptions of various works, making use of the screen differently from the standard by changing its quantity, disposition space, form and materiality.

A obstrução de emissores tem sido um entrave para a microirrigação. Porém, tem-se notado poucos estudos relativos ao desenvolvimento de equipamentos que auxiliam na prevenção da obstrução de emissores nos últimos anos. Os estudos realizados nesta linha estão geralmente ligados à caracterização dos sistemas em uso. O objetivo deste trabalho foi desenvolver um sistema de filtragem com reversão automática de fluxo, de alta frequência. O sistema foi concebido para operar com água de baixa qualidade, com inversão de fluxo e limpezas automáticas e com volume mínimo de água para realização das limpezas. As decisões do controlador do sistema de filtragem têm como base a perda de carga, obtida por meio de transdutores de pressão instalados na entrada e na saída do sistema. O protótipo final é composto, basicamente, por três filtros de tela e onze válvulas solenoides controladas eletronicamente. Determinou-se a curva de perda de carga em função da vazão, a eficiência de retenção e o volume mínimo de água para limpeza dos filtros. A eficiência de retenção de partículas foi determinada em delineamento experimental inteiramente aleatorizado em esquema fatorial, sendo testados três fatores: tempo de reversão (15 e 30 s); incremento da perda de carga (25 e 50%) e concentração de sólidos (500 e 1000 mg L-1). A eficiência de retenção de sólidos totais foi de 71,7 e 78,3% para as concentrações de 500 e 1000 mg L-1, respectivamente, tendo apresentado diferença significativa a 1% de probabilidade. Entretanto, a eficiência retenção de sólidos maiores que 50 ?m (Ed > 50) foi de 98,6 ± 0,7%, não sendo significante para nenhum dos tratamentos ao nível de significância de 1%. O volume médio de água despendido durante as limpezas foi de 5,39 L por limpeza, que representou um volume de água de limpeza por volume de água filtrada de 8,0 e 12,6 L m-3, para as concentrações de 500 e 1000 mg L-1, respectivamente. Os valores de eficiência energética do sistema de filtragem variaram de 80 a 90% para a vazão de 2 m3 h-1 com pressão de entrada entre 15 a 40 mca. As limpezas do sistema de filtragem não foram totalmente eficazes na retomada da perda de carga, com tendência de aumento com o tempo. A inversão de fluxo com frequências de 11,11 e 22,22 mHz influenciou na evolução da perda de carga do sistema de filtragem, tornando-a mais lenta que a evolução para o sistema funcionando sem inversão de fluxo. Considerou-se que o sistema de filtragem desenvolvido apresentou potencial para filtragem da água de irrigação com baixa qualidade, porém necessita de manutenções periódicas para limpeza do elemento filtrante. A perda de carga admissível do sistema de filtragem deve ser o valor mais restritivo entre o critério de desempenho de retenção de partículas e o de variação de vazão do sistema de irrigação. / Emitters clogging have been a barrier to trickle irrigation. Just a few studies have been performed concerning equipments which assist in preventing emitters clogging in recent years, especially regarding to development equipment. Studies carried out on this issue are usually linked to the characterization of systems in use. The aim of this study was to develop a filtering system with automatic flow reversal of high frequency. The system is designed to operate with low quality water, with reverse flow and automatic cleanings and with minimum volume of water to perform the cleaning. Decisions by the controller of the filtration system are based on head loss, obtained by pressure transducers installed at the upstream and downstream of the system. The final prototype consists of three screen filters and eleven electronically controlled solenoid valves. The curve of head loss was determined as a function of water flow, retention efficiency and minimum volume of water required for cleaning the filters. The efficiency in particle retention was determined following a completely randomized experimental design in a factorial scheme in which three factors were tested: reversal time (15 and 30 s) increase in head loss (25 and 50%) and solids concentration (500 and 1000 mg L-1). The total solids retention efficiency was 71.7 and 78.3% for concentrations of 500 and 1000 mg L-1, respectively, presenting a significant difference at 1%. However, when analyzing the retention efficiency of solids larger than 50 ?m (Ed> 50), none of the treatments was significant at 1%, whose efficiency was 98.6 ± 0.7%. The mean volume of water expended during the cleaning was 5.39 L. It represented a volume of water for cleaning per volume of filtered water from 8.0 and 12.6 L m-3, to concentrations of 500 and 1000 mg L-1, respectively. The energy efficiency values of filtering system ranged from 80 to 90% considering flow rate of 2 m3 h-1 and inlet pressure ranging from 15 to 40 mca. The filtering system cleaning was not totally effective in reestablishing the head loss, with an upward trend over time. The reverse flow with frequency of 11.11 and 22.22 mHz influenced the head loss evolution of the filtration system, making it slower than the trend for the system running without flow reversal. The developed filtration system has potential for filtering low quality irrigation water, but it requires periodic maintenance to clean the filter element. The allowable head loss of the filter system should be the most restrictive value between the criterion of particle retention performance and the flow variation of the irrigation system because of the increase in head loss in the filters.

Le « cinématographe » de Robert Bresson vise à atteindre la vérité du réel d’une façon différente du « cinéma », considéré comme le théâtre photographié. Le cinéma de Robert Bresson, qui est également le résultat de l’application de sa théorie, est constamment dans la négativité de l’image représentative. Le montage bressonien décompose le raccord classique et fragmente l’espace narratif. Dans ce contexte, l’objet dans le cinéma de Bresson, sans appuyer sur le rôle narratif et le sens symbolique, contribue à décomposer la cohérence et la continuité du récit filmique. Comparable à la nature morte hollandaise au XVIIème siècle, la singularité de l’objet dans les films de Bresson, est sa présence non narrative. L’objet matériel et concret s’oriente généralement vers les deux aspects : d’une part, l’objet en gros plan se déconnecte de l’acte et de l’évènement et fait les imaginer dans le hors-champ. La déconnection entre l’objet présenté et l’évènement imaginaire entraîne la problématique de la discontinuité. D’autre part, l’objet, par la composition avec le corps morcelé, produit l’acte et l’évènement qui restitue le récit d’une façon fragmentaire. Cette façon de déconnecter et de fragmenter l’évènement, c’est la manière, pour l’objet, de présenter le réel. Notre étude abordera comment l’objet matériel et non narratif figure l’apparition du réel. / The « cinématographe » of Robert Bresson, has the aim to reach the truth of the reality in a different way than the one commonly used in the « cinéma », considered as being the photographed theater. The cinema of Robert Bresson, which is also the result of the application of his theory, is constantly in the negativity of the represented image. The bressoniens montage breaks into parts the classic match and splits up the narrative space. In this context, the object in the cinema of Bresson, without pressing on the narrative role and the symbolic meaning, contributes to split up the coherence and the continuity of the cinematic narrative. Compared to the Dutch still life in the XVIIth century, the peculiarity of the object in the films of Bresson, is his non narrative presence. The material and concrete object turns generally towards both aspects : on one hand, the object disconnects from the act and from the event, and the disconnection involves in the question of discontinuity. On the other hand, by the composition with a part of the body, the object produces the act and the event which create the narrative in a fragmentary way. This discontinuity and the fragment is the way, for the object, of presenting the reality. Our study will devoted to approach how the material and not narrative object contribute to the appearance of the reality.

ABSTRACT: “The real problem of blindness is not the loss of eyesight. The real problem is the misunderstanding and lack of information that exist. If a blind person has proper training and opportunity, blindness can be reduced to a physical nuisance.”- National Federation of the Blind (NFB) Multi-touch screen is a relatively new and revolutionary technology in mobile phone industry. Being mostly software driven makes these phones highly customizable for all sorts of users including blind and visually impaired people. In this research, we present new interface layouts for multi-touch screen mobile phones that enable visionless people to enter text in the form of Braille cells. Braille is the only way for these people to directly read and write without getting help from any extra assistive instruments. It will be more convenient and interesting for them to be provided with facilities to interact with new technologies using their language, Braille. We started with a literature review on existing eyes-free text entry methods and also text input devices, to find out their strengths and weaknesses. At this stage we were aiming at identifying the difficulties that unsighted people faced when working with current text entry methods. Then we conducted questionnaire surveys as the quantitative method and interviews as the qualitative method of our user study to get familiar with users’ needs and expectations. At the same time we studied the Braille language in detail and examined currently available multi-touch mobile phone feedbacks. At the designing stage, we first investigated different possible ways of entering a Braille “cell” on a multi-touch screen, regarding available input techniques and also considering the Braille structure. Then, we developed six different alternatives of entering the Braille cells on the device; we laid out a mockup for each and documented them using Gestural Modules Document and Swim Lanes techniques. Next, we prototyped our designs and evaluated them utilizing Pluralistic Walkthrough method and real users. Next step, we refined our models and selected the two bests, as main results of this project based on good gestural interface principles and users’ feedbacks. Finally, we discussed the usability of our elected methods in comparison with the current method visually impaired use to enter texts on the most popular multi-touch screen mobile phone, iPhone. Our selected designs reveal possibilities to improve the efficiency and accuracy of the existing text entry methods in multi-touch screen mobile phones for Braille literate people. They also can be used as guidelines for creating other multi-touch input devices for entering Braille in an apparatus like computer.

Syfte Mobila enheters skärmar har de senaste åren ökat mycket i storlek. Detta har skapat problem för användarupplevelsen. Därmed är studiens syfte: Hur appar till smartphones med större skärmar bör utvecklas i framtiden för att ge så bra UX som möjligt.   För att kunna besvara syftet har det brutits ned i tre frågeställningar:  Vilka parametrar(typer av objekt) påverkas mest av olika skärmstorlekar? Föredras olika layouter beroende på skärmstorlek?  Hur stor del av skärmen kan nås med ett enhandsgrepp? Metod För att besvara studiens första frågeställning har en litteraturstudie gjorts. Den utgjorde sedan grunden för en enkät i form av en applikation, som besvarade studiens andra och tredje frågeställningar. I den fick testpersonerna rangordna olika layouter beroende på hur de tyckte att användarupplevelsen var. Testerna genomfördes på en iPhone 4S och en iPhone 6S Plus för att få fram skillnader mellan olika skärmstorlekar. Resultat Det studien kom fram till var att det är viktigt att placera viktiga objekt inom räckvidd för användaren när ett enhandsgrepp används. Objekt som placerats i skärmens kanter eller hörn är ofta svåra att nå på en större skärm, vilket innebär att sådan placering bör undvikas. Implikationer Studien kan både hjälpa till vid framtida forskning om användarupplevelse och räckvidd, men också ge rekommendationer om vad som är viktigt att tänka på vid apputveckling till smartphones med större skärmar. Begränsningar Eftersom studien utfördes under begränsad tid fanns inte möjlighet till fler tester. / Purpose Smartphone screens have in recent years increased greatly in size. This has created problems for the user experience. Thus, the purpose of the study is: How mobile applications for smartphones with larger screens should be developed in the future to provide as good UX as possible. In order to answer the purpose it has been broken down into three research questions: Which parameters (type of objects) are most affected by different screen sizes? Depending on the screen size, are different layouts preferred? How much of the screen can be reached by one handed use? Method A study of literature is made to answer the first research question. It became the basis of a questionnaire in the form of an application, which answered the study's second and third research questions. The test subjects ranked different layouts depending on their perceived user experience. The tests were conducted on an iPhone 4S and an iPhone 6S Plus to evaluate the differences between different screen sizes. Findings The study concluded that it is important to place essential items within the user’s reach when one hand is used. Items placed at the edges or corners of the screen are often difficult to reach on a larger screen, which means that avoiding such placement is preferred. Implications The study can both be of service in future research on user experience and reach, but also give recommendations on what is important to take into consideration when developing mobile applications for smartphones with larger screens. Limitations Since the study was conducted over a limited period of time there was no opportunity for more tests.