matching has been studied with focus on the single- domain setting, while less attention is given to the hetero- geneous environment of the Web, where data comes from dierent domains and are associated with dierent schemas. For this heterogeneous setting, we propose an unsupervised schema-agnostic approach that focuses on the renement (disambiguation) of candidate instances (resulting from block- ing). Given instances of a source dataset that belong to a class, it computes candidates in the target datasets and re- nes them such that the remaining matches correspond to the source instances at the class level. However, no schema knowledge and explicit correspondences between classes in the source and target datasets are required for this. Rather, the disambiguation is performed based on an instance-based representation of classes computed online. We evaluated our work using experiments on large-scale real-world datasets provided by a benchmark. The proposed solution outper- formed two alternative approaches for instance matching in 70% of the cases, and in those cases we improved average F-measure by 10%.

Purpose: To describe the history, clinical findings, and possible etiologies of ophthalmic findings discovered in 7 astronauts after long-duration space flight, and document vision changes in approximately 300 additional astronauts.Design: Retrospective, observational examination of ophthalmic findings in 7 astronauts and analysis of postflight questionnaires regarding in-flight vision changes in approximately 300 additional astronauts.Participants: Seven astronauts with ophthalmic anomalies upon return from long-duration space missions to the International Space Station and 300 additional astronauts who completed postflight questionnaires regarding in-flight vision changes.Methods: Before and after long-duration space flight, all 7 subjects underwent complete eye examinations, including cycloplegic and/or manifest refraction and fundus photography. Six underwent postmission optical coherence tomography (OCT) and magnetic resonance imaging (MRI); 4 had lumbar punctures (LP). Approximately 300 astronauts were queried regarding visual changes during space missions.Main Outcome Measures: Refractive change, fundus photograph examination, retina OCT, orbital MRI, LP opening pressures, and examination of visual acuity data.Results: After 6 months of space flight, 7 astronauts had ophthalmic findings, consisting of disc edema in 5, globe flattening in 5, choroidal folds in 5, cotton wool spots (CWS) in 3, nerve fiber layer thickening by OCT in 6, and decreased near vision in 6 astronauts. Five of 7 with near vision complaints had a hyperopic shift >= + 0.50 diopters (D) between pre/postmission spherical equivalent refraction in 1 or both eyes (range, +0.50 to +1.75 D). These 5 showed globe flattening on MRI. Lumbar punctures performed in the 4 with disc edema documented opening pressures of 22, 21, 28, and 28.5 cm H2O performed 60, 19, 12, and 57 days postmission, respectively. The 300 postflight questionnaires documented that approximately 29% and 60% of astronauts on short and long-duration missions, respectively, experienced a degradation in distant and near visual acuity. Some of these vision changes remain unresolved years after flight.Conclusions: We hypothesize that the optic nerve and ocular changes we describe may result from cephalad fluid shifts brought about by prolonged microgravity exposure. The findings we report may represent parts of a spectrum of ocular and cerebral responses to extended microgravity exposure.Financial Disclosure(s): The authors have no proprietary or commercial interest in any of the materials discussed in this article. Ophthalmology 2011; 118: 2058-2069 (C) 2011 by the American Academy of Ophthalmology.

Efficient data dissemination from a single source node to multiple receiving nodes on the Internet is crucial for many applications such as P2P streaming. Existing data dissemination schemes are typically accomplished using overlay multicast trees. These overlay multicast trees, however, do not achieve the full bandwidth capacity since the leaf nodes do not contribute their bandwidth to the system. On the other hand, all the nodes in a properly constructed topology can contribute their bandwidth, resulting in high overall system throughput. We define the notion of throughput efficiency to measure the performance of different data dissemination schemes from a single source node to multiple destination nodes. Using the proposed throughput efficiency, we propose an algorithm for constructing an overlay structured forest that enables high-bandwidth data dissemination in a network with roughly homogeneous capacity. The proposed structured forest and the associated data dissemination algorithm are designed to achieve the following: (1) small end-to-end delay, O((logN)/sup 2/), from the source node to any node (N is the number of destination nodes); (2) small out-degree, O(C), for any node (C is the upload bandwidth); (3) optimal bandwidth usage for all nodes.