23 research outputs found
The James Webb Space Telescope Mission
Twenty-six years ago a small committee report, building on earlier studies,
expounded a compelling and poetic vision for the future of astronomy, calling
for an infrared-optimized space telescope with an aperture of at least .
With the support of their governments in the US, Europe, and Canada, 20,000
people realized that vision as the James Webb Space Telescope. A
generation of astronomers will celebrate their accomplishments for the life of
the mission, potentially as long as 20 years, and beyond. This report and the
scientific discoveries that follow are extended thank-you notes to the 20,000
team members. The telescope is working perfectly, with much better image
quality than expected. In this and accompanying papers, we give a brief
history, describe the observatory, outline its objectives and current observing
program, and discuss the inventions and people who made it possible. We cite
detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space
Telescope Overview, 29 pages, 4 figure
A framework for conceptualizing, representing, and analyzing distributed interaction.
The relationship between interaction and learning is a central concern of the learning sciences, and analysis of interaction has emerged as a major theme within the current literature on computersupported collaborative learning. The nature of technology-mediated interaction poses analytic challenges. Interaction may be distributed across actors, space, and time, and vary from synchronous, quasi-synchronous, and asynchronous, even within one data set. Often multiple media are involved and the data comes in a variety of formats. As a consequence, there are multiple analytic artifacts to inspect and the interaction may not be apparent upon inspection, being distributed across these artifacts. To address these problems as they were encountered in several studies in our own laboratory, we developed a framework for conceptualizing and representing distributed interaction. The framework assumes an analytic concern with uncovering or characterizing the organization of interaction in sequential records of events. The framework includes a media independent characterization of the most fundamental unit of interaction, which we call uptake. Uptake is present when a participant takes aspects of prior events as having relevance for ongoing activity. Uptake can be refined into interactional relationships of argumentation, information sharing, transactivity, and so forth. for specific analytic objectives. Faced with the myriad of ways in which uptake can manifest in practice, we represent data using graphs of relationships between events that capture the potential ways in which one act can be contingent upon another. These contingency graphs serve as abstract transcripts that document in one representation interaction that is distributed across multiple media. This paper summarizes the requirements that motivate the framework, and discusses the theoretical foundations on which it is based. It then presents the framework and its application in detail, with examples from our work to illustrate how we have used it to support both ideographic and nomothetic research, using qualitative and quantitative methods. The paper concludes with a discussion of the framework’s potential role in supporting dialogue between various analytic concerns and methods represented in CSCL
Quantitative description of oscillatory zoning in basaltic to dacitic plagioclases from the Shirahama Group, Japan
Effects of two mitosis inhibitors (Colchicine and Vinblastine) on the distribution and axonal transport of noradrenaline storage particles, studied by fluorescence and electron microscopy
Clinical Manifestations and Pathophysiological Mechanisms of the Wiskott-Aldrich Syndrome.
The Wiskott-Aldrich syndrome (WAS) is a rare X-linked disorder originally described by Dr. Alfred Wiskott in 1937 and Dr. Robert Aldrich in 1954 as a familial disease characterized by infections, bleeding tendency, and eczema. Today, it is well recognized that the syndrome has a wide clinical spectrum ranging from mild, isolated thrombocytopenia to full-blown presentation that can be complicated by life-threatening hemorrhages, immunodeficiency, atopy, autoimmunity, and cancer. The pathophysiology of classic and emerging features is being elucidated by clinical studies, but remains incompletely defined, which hinders the application of targeted therapies. At the same time, progress of hematopoietic stem cell transplantation and gene therapy offer optimistic prospects for treatment options aimed at the replacement of the defective lymphohematopoietic system that have the potential to provide a cure for this rare and polymorphic disease
Proteolysis of vimentin and desmin by the Ca2+-activated proteinase specific for these intermediate filament proteins
Teaching students to think spatially through embodied actions: Design principles for learning environments in science, technology, engineering, and mathematics
Closing the Loop
Background Two widely used artificial pancreas (AP) control algorithms are the model
predictive control (MPC) and the proportional integral derivative (PID) algorithms. Numerous
studies across different settings have used both algorithms with positive results, but there
has never been a randomized clinical trial directly comparing the effectiveness of each. This
study aimed to compare individual-personalized MPC and PID controls under nonideal but
comparable clinical conditions. Methods After a pilot safety and feasibility study (n= 10),
closed-loop control (CLC) was conducted and evaluated in a randomized, crossover trial
that included 20 additional adults with type 1 diabetes. Both the MPC and PID algorithms
were compared during supervised 27.5 hour CLC sessions. The algorithms were tested by
evaluating control performance following a 65 g dinner, 50 g breakfast, and unannounced..