Samuel Sudar

P53 is required for the developmental restriction in Müller glial proliferation in mouse retina

Müller glia are normally mitotically quiescent cells, but in certain pathological states they can re‐enter the mitotic cell cycle. While several cell cycle regulators have been shown to be important in this process, a role for the tumor suppressor, p53, has not been demonstrated. Here, we investigated a role for p53 in limiting the ability of Müller glia to proliferate in the mature mouse retina. Our data demonstrate that Müller glia undergo a developmental restriction in their potential to proliferate. Retinal explants or dissociated cultures treated with EGF become mitotically quiescent by the end of the second postnatal week. In contrast, Müller glia from adult trp53−/+ or trp53−/− mice displayed a greater ability to proliferate in response to EGF stimulation in vitro. The enhanced proliferative ability of trp53 deficient mice correlates with a decreased expression of the mitotic inhibitor Cdkn1a/p21cip and an increase in c‐myc, a transcription factor that promotes cell cycle progression. These data show that p53 plays an essential role in limiting the potential of Müller glia to re‐enter the mitotic cycle as the retina matures during postnatal development.

ODK tables: building easily customizable information applications on Android devices

ODK Tables is an Android app that allows users to enter and curate tabular data. Users can explore the data through a variety of built-in views or build custom views using HTML/JavaScript. It also supports the linking of multiple data tables. Data values can be updated in a variety of ways, including using mobile data collection tools such as ODK Collect, that support rich data types including multi-media, or by communicating with low-cost phones over SMS. Additionally, ODK Tables supports a simple synchronization scheme appropriate for a distributed workforce and backed up on cloud servers. The goal of ODK Tables is to lower barriers to developing customized information applications by making it easy to customize data views using standard web technologieś that do not require recompilation. Our experience in working with many organizations in the developing world led us to make feature choices based on their input (through an on-line survey) with particular consideration to the potential pool of developers available. In this paper, we report on our implementation of ODK Tables and some of its performance parameters. We have designed it to be a flexible solution for a variety of use cases, including logistics management, public health, and environment monitoring where previously collected data is often revisited and updated.

Computer Security for Data Collection Technologies

Many organizations in the developing world (e.g., NGOs), include digital data collection in their workflow. Data collected can include information that may be considered sensitive, such as medical or socioeconomic data, and which could be affected by computer security attacks or unintentional mishandling. The attitudes and practices of organizations collecting data have implications for confidentiality, availability, and integrity of data. This work, a collaboration between computer security and ICTD researchers, explores security and privacy attitudes, practices, and needs within organizations that use Open Data Kit (ODK), a prominent digital data collection platform. We conduct a detailed threat modeling exercise to inform our view on potential security threats, and then conduct and analyze a survey and interviews with technology experts in these organizations to ground this analysis in real deployment experiences. We then reflect upon our results, drawing lessons for both organizations collecting data and for tool developers.

Demo: Siskin: Leveraging the Browser to Share Web Content in Disconnected Environments

Schools in the developing world frequently do not have high bandwidth or reliable connections, limiting their access to web content. As a result, schools are increasingly turning to Offline Educational Resources (OERs), employing purpose-built local hardware to serve content. These approaches can be expensive and difficult to maintain in resource-constrained settings. We present Siskin, an alternative approach that leverages the ubiquity of the web browser to provide a distributed content access cache between user devices on the local network. We demonstrate that this system allows access to web pages offline by identifying the browser as a ubiquitous platform.

Open Data Kit 2.0: A Services-Based Application Framework for Disconnected Data Management

In resource-constrained communities, organizations often use information and communication technologies to amplify their limited resources to improve education, health, and economic opportunity. Over two-thirds of the worlds population have mobile phones, yet less than half are connected to the Internet [23]. Organizations helping disadvantaged populations often rely on mobile devices as their primary computing resource because of their availability in resource-constrained contexts. However, to reach under-served populations, mobile applications often operate in areas with no connectivity or challenged network environments. Unfortunately, many mobile application frameworks are generally not well-suited for long periods of disconnected data collection and management. Furthermore, mobile application frameworks are generally aimed at users with significant technical skills and resources. In this paper, we discuss our experiences building, deploying, and refining the Open Data Kit (ODK) 2.0 tool suite. ODK 2.0 is a modular application framework that facilitates organizations with limited technical capacity to build application-specific information services for use in disconnected environments. We discuss ODK 2.0s flexible abstractions that enable users of varying technical skill levels to create customizable mobile data management solutions. We present ODK 2.0 case studies involving multiple organizations and discuss lessons learned from building a service-based mobile application framework for disconnected data management.

ODK tables: case studies in deployment

Open Data Kit (ODK) Tables is an Android application that allows users to enter and curate tabular data. Users can view the data through built-in or custom views using HTML/JavaScript. In this paper we discuss our lessons learned from real-world deployments of Tables. Specifically, our initial aim of providing a customized view of a table did not have a sufficient level of customizability. Rather than simply the views of the data tables, the entire application needed to be navigable using web-based tools that do not require recompilation to make presentation changes. We also discuss issues encountered with making the application scalable when faced with real-world datasets.

Siskin: Leveraging the Browser to Share Web Content in Disconnected Environments

Schools in the developing world frequently do not have high bandwidth or reliable connections, limiting their access to web content. As a result, schools are increasingly turning to Offline Educational Resources (OERs), employing purpose-built local hardware to serve content. These approaches can be expensive and difficult to maintain in resource-constrained settings. We present Siskin, an alternative approach that leverages the ubiquity of web browsers to provide a distributed content access cache between user devices on the local network. We demonstrate that this system allows access to web pages offline by identifying the browser as a ubiquitous platform. We build and evaluate a prototype, showing that existing web protocols and infrastructure can be leveraged to create a powerful content cache over a local network.

Computer security for data collection technologies

Many organizations in the developing world (e.g., NGOs), include digital data collection in their workflow. Data collected can include information that may be considered sensitive, such as medical or socioeconomic data, and which could be affected by computer security attacks or unintentional mishandling. The attitudes and practices of organizations collecting data have implications for confidentiality, availability, and integrity of data. This work, a collaboration between computer security and ICTD researchers, explores security and privacy attitudes, practices, and needs within organizations that use Open Data Kit (ODK), a prominent digital data collection platform. We conduct a detailed threat modeling exercise to inform our view on potential security threats, and then conduct and analyze a survey and interviews with technology experts in these organizations to ground this analysis in real deployment experiences. We then reflect upon our results, drawing lessons for both organizations collecting data and for tool developers.

DUCES: A Framework for Characterizing and Simplifying Mobile Deployments in Low-Resource Settings

Mobile devices are increasingly being used in data-focused workflows in low-resource settings. These deployments are frequently orchestrated by organizations with limited technical capacity, making fundamental architectural decisions difficult. We present DUCES, a framework for characterizing mobile deployments along five axes of design. DUCES allows organizations to better understand deployment requirements and simplify decisions regarding deployment architectures. It focuses on the workflows Data flow, User interface, Connectivity model, Edit mode, and Server requirements. We discuss five case studies of data-focused mobile deployments and evaluate them using the DUCES framework. We conclude by discussing how the DUCES framework can be used as a lens by organizations and researchers to understand and simplify mobile deployments.

Demo: open data kit 2.0 tool suite

Open Data Kit (ODK) is an open-source, modular toolkit that enables organizations to build application-specific mobile information services in resource-constrained environments. Feedback from users and developers about limitations experienced with the ODK 1.x set of tools led to a redesign of the system architecture and the creation of new tools. This demonstration presents a revised tool suite called ODK 2.0. This expanded ODK toolkit aims to increase an organizations data collection and management capabilities by supporting data synchronization, adaptable workflows, more configurable presentation screens, and increasing the diversity of input types by enabling new data input methods on mobile devices.