Primordial Nucleosynthesis for the New Cosmology: Determining Uncertainties and Examining Concordance

Big bang nucleosynthesis (BBN) and the cosmic microwave background (CMB) have a long history together in the standard cosmology. The general concordance between the predicted and observed light element abundances provides a direct probe of the universal baryon density. Recent CMB anisotropy measurements, particularly the observations performed by the WMAP satellite, examine this concordance by independently measuring the cosmic baryon density. Key to this test of concordance is a quantitative understanding of the uncertainties in the BBN light element abundance predictions. These uncertainties are dominated by systematic errors in nuclear cross sections. We critically analyze the cross section data, producing representations that describe this data and its uncertainties, taking into account the correlations among data, and explicitly treating the systematic errors between data sets. Using these updated nuclear inputs, we compute the new BBN abundance predictions, and quantitatively examine their concordance with observations. Depending on what deuterium observations are adopted, one gets the following constraints on the baryon density: OmegaBh^2=0.0229\pm0.0013 or OmegaBh^2 = 0.0216^{+0.0020}_{-0.0021} at 68% confidence, fixing N_{\nu,eff}=3.0. Concerns over systematics in helium and lithium observations limit the confidence constraints based on this data provide. With new nuclear cross section data, light element abundance observations and the ever increasing resolution of the CMB anisotropy, tighter constraints can be placed on nuclear and particle astrophysics. ABRIDGEDComment: 54 pages, 20 figures, 5 tables v2: reflects PRD version minor changes to text and reference

Automated Promotion of Technology Acceptance by Clinicians Using Relational Agents

Abstract. Professionals are often resistant to the introduction of technology and can feel threatened if they perceive the technology as replacing some aspect of their jobs. We anticipated some of these problems in the process of introducing a bedside patient education system to a hospital, especially given that the system presents itself as a “virtual discharge nurse ” in which an animated nurse agent interacts with patients using simulated face-to-face conversation. To increase acceptance by nursing staff we created a version of the character designed to build trust and rapport through a personalized conversation with them. In a randomized trial, we compared responses after 15 minute in-service briefings on the technology versus responses to the same briefings plus a personalized conversation with the agent. We found that the nurses who participated in briefings that included the personalized conversation had significantly greater acceptance of and lower feelings of being threatened by the agent

Methodological reflections on gesture analysis in SLA and bilingualism research

Contains fulltext : 79151.pdf (publisher's version ) (Closed access)28 p