Quantum simulation of multiple-exciton generation in a nanocrystal by a single photon

We have shown theoretically that efficient multiple exciton generation (MEG) by a single photon can be observed in small nanocrystals (NCs). Our quantum simulations that include hundreds of thousands of exciton and multi-exciton states demonstrate that the complex time-dependent dynamics of these states in a closed electronic system yields a saturated MEG effect on a picosecond timescale. Including phonon relaxation confirms that efficient MEG requires the exciton--biexciton coupling time to be faster than exciton relaxation time

Designing antibiotic cycling strategies by determining and understanding local adaptive landscapes

The evolution of antibiotic resistance among bacteria threatens our continued ability to treat infectious diseases. The need for sustainable strategies to cure bacterial infections has never been greater. So far, all attempts to restore susceptibility after resistance has arisen have been unsuccessful, including restrictions on prescribing [1] and antibiotic cycling [2,3]. Part of the problem may be that those efforts have implemented different classes of unrelated antibiotics, and relied on removal of resistance by random loss of resistance genes from bacterial populations (drift). Here, we show that alternating structurally similar antibiotics can restore susceptibility to antibiotics after resistance has evolved. We found that the resistance phenotypes conferred by variant alleles of the resistance gene encoding the TEM {\beta}-lactamase (blaTEM) varied greatly among 15 different {\beta}-lactam antibiotics. We captured those differences by characterizing complete adaptive landscapes for the resistance alleles blaTEM-50 and blaTEM-85, each of which differs from its ancestor blaTEM-1 by four mutations. We identified pathways through those landscapes where selection for increased resistance moved in a repeating cycle among a limited set of alleles as antibiotics were alternated. Our results showed that susceptibility to antibiotics can be sustainably renewed by cycling structurally similar antibiotics. We anticipate that these results may provide a conceptual framework for managing antibiotic resistance. This approach may also guide sustainable cycling of the drugs used to treat malaria and HIV

Language Learners: The Role of Online Materials

The Role of Online Materials Brief describes how English language learners interact with online learning materials and resources in a digital literacy acquisition program. The Research Briefs series highlight key findings about how underserved adults acquire digital literacy skills, and include quotes from participants and practitioners. The Briefs are designed to be accessible by practitioners, program administrators, and policy makers to inform and enhance digital literacy programs

Program Design: Tutor-Facilitated Digital Literacy Acquisition

The Tutor Facilitated Digital Literacy Acquisition Brief highlights the importance of tutors in a digital literacy acquisition program and points to some specific ways tutors were able to support learners. The Research Briefs series highlight key findings about how underserved adults acquire digital literacy skills, and include quotes from participants and practitioners. The Briefs are designed to be accessible by practitioners, program administrators, and policy makers to inform and enhance digital literacy programs

Community Connections: Digital Literacy Acquisition Policy Brief

This case study describes how the digital literacy acquisition program in a rural community was sustained through formal and informal connections across a variety of organizations and community institutions. The case study describes the setting, the details of how tutor facilitated, self paced learning was organized, and the various ways connections were made across organizations. Five types of connections are identified: formal top-level partnerships, local connections, library/workforce partnership, school/workforce connections, informal community connections, and lab coordinator/tutor/learner connections. Implications for these findings include how policy makers and other key stakeholders may benefit from recognizing and building on the ways people in the field marshal formal and informal resources to create and sustain vibrant programs

Learners: Self-Paced Learning

The Self Paced Learning Brief details findings that demonstrate learners and tutors’ preferences for working at their own pace to learn digital literacy skills. The Research Briefs series highlight key findings about how underserved adults acquire digital literacy skills, and include quotes from participants and practitioners. The Briefs are designed to be accessible by practitioners, program administrators, and policy makers to inform and enhance digital literacy programs

Learners: Impact

The Impact Brief introduces findings that illustrate the tremendous positive impact that learning digital literacy can have on adult learners’ lives. The Research Briefs series highlight key findings about how underserved adults acquire digital literacy skills, and include quotes from participants and practitioners. The Briefs are designed to be accessible by practitioners, program administrators, and policy makers to inform and enhance digital literacy programs

Job Seeking Learners: Digital Literacy Acquisition Case Study

This case study investigates the experience of digital literacy acquisition among adult job seekers, offering an overview of the various lab settings accessed by job-seeking learners, as well as the different ways that tutor-facilitated, self-paced learning was organized. Examination of the learner path as experienced by job seekers reveals the challenge for learners of seeing the relevance of digital literacy acquisition when faced with the urgent need of having to find employment. Also discussed in the case study are the significant impact of the relationships that developed between learners and tutors, the role that tutors play in building relevance for the learners, and creating job readiness training opportunities. Implications include the ways that lab coordinators and tutors working with job-seeking learners can support them by acknowledging the reality of the learners’ lives while supporting them through the digital literacy acquisition process. The findings indicate that labs serving job-seeking learners are well situated to introduce individuals to the opportunities available through computer and Internet use that go beyond employment to deeper civic and social engagement

Program Design: Learning Digital Skills in a Time-limited Program

The Learning Digital Skills in a Time-limited Program Brief details how one program struck a balance between meeting the needs of learners and maximizing limited program resources. The Research Briefs series highlight key findings about how underserved adults acquire digital literacy skills, and include quotes from participants and practitioners. The Briefs are designed to be accessible by practitioners, program administrators, and policy makers to inform and enhance digital literacy programs

Operationalizing Success in a Digital Learning Environment Designed to Support Vulnerable Adults

This study seeks to examine patterns of successful learning identified when economically vulnerable, underserved, and high-need adults engaged in self-access, tutor facilitated learning to acquire digital literacy. In large part, this diverse population of learners has been left behind in the digital revolution, thus compounding their social, economic, and educational disadvantages. These individuals have unique patterns of engagement within educational endeavors, at times dropping in and out of programs as a result of social and economic impediments that permeate their lives. Traditional means of identifying success in their learning endeavors inadequately describe the paths these learners take on the road to acquiring digital literacy. This research explores ways to operationalize the success of adult learners who come to public access computer labs in libraries, adult education, and community organizations for tutor-facilitated support to acquire digital literacy. Findings suggest that adults’ digital literacy learning, and the programs that support this learning, are best explored using aspects of goal directed learning that consider dimensions of the learners’ self-directed goals as a means of learner and program success