University of Massachusetts Boston

About: University of Massachusetts Boston is a education organization based out in Boston, Massachusetts, United States. It is known for research contribution in the topics: Population & Health care. The organization has 6541 authors who have published 12918 publications receiving 411731 citations. The organization is also known as: UMass Boston.

Observation of Amplification in a Strongly Driven Two-Level Atomic System at Optical Frequencies

Abstract: We report the observation of optical amplification in a two-level atomic system driven by a strong, resonant field. By exciting an atomic beam of two-level sodium atoms simultaneously with a strong, fixed-frequency driving field and a weak, tunable, probe field, we have measured the absorption (amplification) line-shape function for several values of driving field strength. In addition, we have verified theoretical predictions that higher amplification is obtained when the strong field is detuned from exact resonance.

Molecular Determinants of a Symbiotic Chronic Infection

Abstract: Rhizobial bacteria colonize legume roots for the purpose of biological nitrogen fixation. A complex series of events, coordinated by host and bacterial signal molecules, underlie the development of this symbiotic interaction. Rhizobia elicit de novo formation of a novel root organ within which they establish a chronic intracellular infection. Legumes permit rhizobia to invade these root tissues while exerting control over the infection process. Once rhizobia gain intracellular access to their host, legumes also strongly influence the process of bacterial differentiation that is required for nitrogen fixation. Even so, symbiotic rhizobia play an active role in promoting their goal of host invasion and chronic persistence by producing a variety of signal molecules that elicit changes in host gene expression. In particular, rhizobia appear to advocate for their access to the host by producing a variety of signal molecules capable of suppressing a general pathogen defense response.

Capitalizing on Content: Information Adoption in Two Online communities

Abstract: Online communities enable members to exchange messages, and rich content is generated in the wake of these contributions. Little research has systematically investigated how this content is utilized. In this paper we use the HeuristicSystematic Model of information processing to explore the mechanisms by which the potential value of these information assets can be realized. We argue that the extent to which message content and heuristic cues influence the validity assessment process is moderated by two factors: how consistent the new information is with what is already known and the extent to which information-seeking members are actively searching for on-topic information to satisfy their specific information needs. Survey data collected from two online communities generally support the hypotheses derived from this model. This study demonstrates that community members process information from online communities in a highly contextual manner that may extend to the functionality of the technical tools provided by the online communities. It also suggests numerous opportunities for future research and potential ways that online communities might improve their information sharing.