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Open Access Publications from the University of California

Scholarly Works (30 results)

  • Article
  • Peer Reviewed
UC San Diego Previously Published Works (2008)
    Cover page: Automated Detection and Analysis of Foraging Behavior in C. elegans
    • Article
    • Peer Reviewed
    UCLA Previously Published Works (2015)
    We employ a recently proposed model [Murisic et al., "Dynamics of particle settling and resuspension in viscous liquids," J. Fluid. Mech. 717, 203-231 (2013)] to study a finite-volume, particle-laden thin film flowing under gravity on an incline. For negatively buoyant particles with concentration above a critical value and buoyant particles, the particles accumulate at the front of the flow forming a particle-rich ridge, whose similarity solution is of the rarefaction-singular shock type. We investigate the structure in detail and find that the particle/fluid front advances linearly to the leading order with time to the one-third power as predicted by the Huppert solution [H. E. Huppert, "Flow and instability of a viscous current down a slope," Nature 300, 427-419 (1982)] for clear fluid (i.e., in the absence of particles). We also explore a deviation from this law when the particle concentration is high. Several experiments are carried out with both buoyant and negatively buoyant particles whose results qualitatively agree with the theoretics.
      Cover page: Rarefaction-singular shock dynamics for conserved volume gravity driven particle-laden thin film
      • Article
      • Peer Reviewed
      UC San Diego Previously Published Works (2005)

      Intelligent environments can be viewed as systems where humans and machines (rooms) collaborate. Intelligent (or smart) environments need to extract and maintain an awareness of a wide range of events and human activities occurring in these spaces. This requirement is crucial for supporting efficient and effective interactions among humans as well as humans and intelligent spaces. Visual information plays an important role for developing accurate and useful representation of the static and dynamic states of an intelligent environment. Accurate and efficient capture, analysis, and summarization of the dynamic context requires the vision system to work at multiple levels of semantic abstractions in a robust manner. In this paper, we present details of a long-term and ongoing research project, where indoor intelligent spaces endowed with a range of useful functionalities are designed, built, and systematically evaluated. Some of the key functionalities include: intruder detection; multiple person tracking; body pose and posture analysis; person identification; human body modeling and movement analysis; and for integrated systems for intelligent meeting rooms, teleconferencing, or performance spaces. The paper includes an overall system architecture to support design and development of intelligent environments. Details of panoramic (omnidirectional) video camera arrays, calibration, video stream synchronization, and real-time capture/processing are discussed. Modules for multicamera-based multiperson tracking, event detection and event based servoing for selective attention, voxelization, streaming face recognition, are also discussed. The paper includes experimental studies to systematically evaluate performance of individual video analysis modules as well as to evaluate basic feasibility of an integrated system for dynamic context capture and event based servoing, and semantic information summarization.

        Cover page: Dynamic context capture and distributed video arrays for intelligent spaces
        • Article
        • Peer Reviewed
        International Organization of Citrus Virologists Conference Proceedings (1957-2010), Volume 11, Issue 11 (1991)
          Cover page: Spatial Pattern Analysis of Citrus Greening in Shantou, China
          • Article
          • Peer Reviewed
          UC San Diego Previously Published Works (2007)
            Cover page: Automated tracking of multiple C. elegans with articulated models
            • Article
            • Peer Reviewed
            UC Davis Previously Published Works (2014)

            Background

            Cats with hypertrophic cardiomyopathy (HCM) are at risk for development of systemic thromboembolic disease. However, the relationship between platelet activation state and cardiovascular parameters associated with HCM is not well described.

            Objectives

            To characterize platelet activation by flow cytometric evaluation of platelet P-selectin and semiquantitative Western blot analysis of soluble platelet-endothelial cell adhesion molecule-1 (sPECAM-1).

            Animals

            Eight normal healthy cats (controls) owned by staff and students of the School of Veterinary Medicine and 36 cats from the UC Davis Feline HCM Research Laboratory were studied.

            Methods

            Platelet-rich plasma (PRP) was used for all flow cytometry studies. Platelet surface CD41 and P-selectin expression were evaluated before and after ADP stimulation. sPECAM-1 expression was evaluated by Western blot analysis of platelet-poor plasma that had been stabilized with aprotinin. Standard echocardiographic studies were performed.

            Results

            Resting platelets from cats with severe HCM had increased P-selectin expression compared to controls, and expressed higher surface density of P-selectin reflected by their increased mean fluorescence intensities (MFI). Stimulation with ADP also resulted in significantly increased P-selectin MFI of platelets from cats with severe HCM. Increased P-selectin expression and MFI correlated with the presence of a heart murmur and end-systolic cavity obliteration (ESCO). sPECAM-1 expression from cats with moderate and severe HCM was significantly increased above those of control cats.

            Conclusions and clinical importance

            P-selectin and sPECAM expression may be useful biomarkers indicating increased platelet activation in cats with HCM.
              Cover page: Platelet Activation in Cats with Hypertrophic Cardiomyopathy
              • Article
              • Peer Reviewed
              UC San Francisco Previously Published Works (2014)
              Whether human induced pluripotent stem cells (hiPSCs) are epigenetically identical to human embryonic stem cells (hESCs) has been debated in the stem cell field. In this study, we analyzed DNA methylation patterns in a large number of hiPSCs (n = 114) and
                • Article
                • Peer Reviewed
                UC Davis Previously Published Works (2020)
                We present 36 spectroscopically confirmed intrinsically UV-faint Lyα-emitting galaxies from follow-up observations with Keck/DEep Imaging Multi-Object Spectrograph of gravitationally lensed high-redshift candidates. Candidates were selected to be between 5 ≲ z ≲ 7 from photometric data using Hubble Space Telescope and Spitzer imaging surveys. We performed an integrated photometric redshift probability cut >1% between 5 < z < 7 to construct a sample of 198 high-redshift objects. Our sample spans intrinsic UV luminosities from a few L∗ down to 0.001L∗. We identified 19 high-confidence detections and 17 likely detections of Lyα. We divided our sample into lower-redshift (z ∼ 5.5) and higher-redshift (z ∼ 6.5) bins and ran Monte Carlo trials, incorporating the strengths of the Lyα emission and the photometric redshifts of the nondetections. Considering only objects where Lyα could be detected at EW(Lyα) > 25 Å at 3σ at the fiducial depth of our survey, and only those galaxies with EW(Lyα) > 25 Å, and only objects with m AB < 26.8, we found the Lyα emitter (LAE) fraction to be flat or modestly increase from 0.26 0.04 to 0.30 0.04. These values are consistent with a rising LAE fraction with redshift out to z ∼ 6, but at z ∼ 6.5, there is some tension between our results and results from surveys at intrinsically brighter luminosities. We conclude that intrinsically fainter galaxies have Lyα emission, and there is a steep drop in the LAE fraction from our high-redshift sample at z ∼ 6.5 and from similar galaxies at z ∼ 7.5. This likely indicates we are witnessing the tail end of the epoch of reionization, as such a drop is not expected due to changes of intrinsic galaxy properties between these redshifts.
                  Cover page: Spectroscopically Confirmed Lyα Emitters from Redshift 5 to 7 behind 10 Galaxy Cluster Lenses
                  • Article
                  • Peer Reviewed
                  UC San Francisco Previously Published Works (2016)
                    • Article
                    • Peer Reviewed
                    UC Davis Previously Published Works (2017)
                    The C iii] and C iv rest-frame UV emission lines are powerful probes of the ionization states of galaxies. They have furthermore been suggested as alternatives for spectroscopic redshift confirmation of objects at the epoch of reionization (), where the most frequently used redshift indicator, Lyα, is attenuated by the high fraction of neutral hydrogen in the intergalactic medium. However, currently only very few confirmations of carbon UV lines at these high redshifts exist, making it challenging to quantify these claims. Here, we present the detection of C iv λλ1548, 1551 Å in Hubble Space Telescope slitless grism spectroscopy obtained by GLASS of a Lyα emitter at z = 6.11 multiply imaged by the massive foreground galaxy cluster RXC J2248.7-4431. The C iv emission is detected at the 3σ-5σ level in two images of the source, with marginal detection in two other images. We do not detect significant C iii]λλ1907, 1909 Å emission implying an equivalent width Å (1σ) and (2σ). Combined with limits on the rest-frame UV flux from the He ii λ1640 Å emission line and the O iii]λλ1661, 1666 Å doublet, we put constraints on the metallicity and the ionization state of the galaxy. The estimated line ratios and equivalent widths do not support a scenario where an AGN is responsible for ionizing the carbon atoms. SED fits, including nebular emission lines, imply a source with a mass of log(M/M o) ∼ 9, SFR of around 10 M o yr-1, and a young stellar population old. The source shows a stronger ionizing radiation field than objects with detected C iv emission at and adds to the growing sample of low-mass (log(M/M o) ≲ 9) galaxies at the epoch of reionization with strong radiation fields from star formation.
                      Cover page: The Grism Lens-Amplified Survey from Space (GLASS). XI. Detection of C iv in Multiple Images of the z = 6.11 Lyα Emitter behind RXC J2248.7–4431
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