Visual Recommendations for Network Navigation

Understanding large, complex networks is important for many critical tasks, including decision making, process optimization, and threat detection. Existing network analysis tools often lack intuitive interfaces to support the exploration of large scale data. We present a visual recommendation system to help guide users during navigation of network data. Collaborative filtering, similarity metrics, and relative importance are used to generate recommendations of potentially significant nodes for users to explore. In addition, graph layout and node visibility are adjusted in real‐time to accommodate recommendation display and to reduce visual clutter. Case studies are presented to show how our design can improve network exploration.     

Muscle tissue structural changes and texture development in sea bream, Sparus aurata L., during post-mortem storage

Sea bream, Sparus aurata L., specimens were studied in pre-rigor (3 h) and during the following post-mortem days: 1, 5, 10, 15 and 22. Muscle and textural parameters were evaluated on 6 specimens/stage. Structural results showed scarce fibre-to-fibre detachment on pre-rigor, which increased during the post-mortem degradation. Ultrastructural changes revealed rapid muscle degradation. In pre-rigor myofibrils were detached to both sarcolemma and endomysium. Intermyofibrillar spaces increased and some mitochondriae and sarcoplasmic reticulum were swollen. After 1 day, the sarcolemma appeared occasionally disrupted and the interfibrillar spaces increased. From 5 to 10 days, the I-band and Z line presented some alterations, although these were more severe at 15-22 days. Thus, in these two last stages, loss of I-band, Z line and actin filaments was observed, that coincides with the alteration of the hexagonal arrangement in these advanced stages. Also, the fragmentation of myofibrils increased from 5 to 10 days on. Sarcolemma and endomysium were gradually disrupted throughout the post-mortem stages with total loss at 22 days. Consequently, the interfibrillar spaces increased at last stages. Autophagic mechanisms increased from 5 days on, with an intense destruction of all the intracytoplasmic organelles. Textural parameters decreased from pre-rigor until 5-10 days, mainly associated to detachment of myofibers to sarcolemma-endomysium.     

Multiple-scattering lidar retrieval method: tests on Monte Carlo simulations and comparisons with in situ measurements

A multiple-field-of-view (MFOV) lidar measurement and solution technique has been developed to exploit the retrievable particle extinction and size information contained in the multiple-scattering contributions to aerosol lidar returns. We describe the proposed solution algorithm. The primary retrieved parameters are the extinction coefficient at the lidar wavelength and the effective particle diameter from which secondary products such as the extinction at other wavelengths and the liquid-water content (LWC) of liquid-phase clouds can be derived. The solutions are compared with true values in a series of Monte Carlo simulations and with in-cloud measurements. Good agreement is obtained for the simulations. For the field experiment, the retrieved effective droplet diameter and LWC for the available seven cases studied are on average 15% and 35% (worst case) smaller than the measured data, respectively. In the latter case, the analysis shows that the differences cannot be attributed solely to lidar inversion errors. Despite the limited penetration depth (150-300 m) of the lidar pulses, the results of the studied cases indicate that the retrieved lidar solutions remain statistically representative of measurements performed over the full cloud extent. Long-term MFOV lidar monitoring could thus become a practical and economical option for cloud statistical studies but more experimentation on more varied cloud conditions, especially for LWC, is still needed.     

Fragment shaders for agent animation using finite state machines

In a previous paper we generated animated agents and their behavior using a combination of XML and images. The behavior of agents was specified as a finite state machine (FSM) in XML. We used images to determine properties of the world that agents react to. While this approach is very flexible, it can be made much faster by using the power available in modern GPUs. In this paper we implement FSMs as fragment shaders using three kinds of images: world space images, agent space images and FSM table images. We show a simple example and compare performance of CPU and GPU implementations. Then we examine a more complex example involving more maps and two types of agents (predator–prey). Furthermore we explore how to render agents in 3D more efficiently by using a variation on pseudoinstancing.     

Green leaf phenology at Landsat resolution: Scaling from the field to the satellite

Despite the large number of in situ, plot-level phenological measurements and satellite-derived phenological studies, there has been little success to date in merging these records temporally or spatially. In this research, we bridge this scale gap through higher resolution satellite records (Landsat) and quantify the accuracy of satellite-derived metrics with direct field measurements. We compiled fifty-seven Landsat scenes from southern New England (P12 R51) from 1984 to 2002. Green vegetation areal abundance for each scene was derived from spectral mixture analysis and a single set of endmembers. The leaf area signal was fit with a logistic-growth simulating sigmoid curve to derive phenological markers (half-maximum leaf-onset and offset). Spring leaf-onset dates in homogenous stands of deciduous forests displayed significant and persistent local variability. The local variability was validated with multiple springtime ground observations (r² = 0.91). The highest degree of verified small-scale variation occurred where contiguous forests displayed leaf-onset gradients of 10-14 days over short distances (< 500 m). These dramatic gradients occur in of low-relief (< 40 m) upland regions. The patterns suggest that microclimates resulting from springtime cold-air drainage may be influential in governing the start of leaf growth; every 4.16 m loss in elevation delayed spring leaf onset by 1 day. These microclimates may be of crucial importance in interpreting in situ records and interpolating phenology from satellite data. Regional patterns from the Landsat analyses suggest topographic, coastal, and land-use controls on phenology. Our results indicate that deciduous forests in the Providence, RI metropolitan area leaf out 5-7 days earlier than comparable rural areas. The platform-independent curve-fit methodology may be extended across platforms and field data. The methodologically consistent approach, in tandem with Landsat data, allows an effective scaling from plot to satellite phenological observations.     

Challenges and solutions for recruiting pregnant smokers into a nicotine replacement therapy trial.

Improvements in smoking cessation interventions for pregnant smokers are needed. One major step is to examine the potential effectiveness of nicotine replacement therapy (NRT). The potential benefits of providing pregnant women with NRT to help them quit smoking are still unknown; early interventions to test the effectiveness and efficacy are vital to advancing the field. This paper describes recruitment efforts for a multiclinic trial to test the effectiveness of NRT use in addition to behavioral therapy in promoting cessation during pregnancy. The biggest challenge is recruiting sufficient numbers of pregnant women. This paper discusses specific obstacles for recruitment and solutions. Knowing the potential pitfalls to recruiting pregnant women into these trials can lead to better studies and thus improved outcomes.     

Prospects for Bose-Einstein condensation in atomic hydrogen and other gases

Current experimental efforts to observe Bose-Einstein condensation in the laboratory are reviewed. New experiments in spin-polarized hydrogen at high density or very low temperatures offer promise of achieving this goal. The possibility of BEC in other elements, H₂,⁴He, and cesium are discussed.