959 research outputs found
Regional differences in store-operated Ca2+Â entry in the epithelium of the intact human lens
An elevated level of Ca2+ is an important factor in cataract, yet precisely how Ca2+ enters the lens is unknown. Lens epithelial cells contain a range of G-proteinâcoupled receptors and receptor tyrosine kinases that induce increases in intracellular Ca2+. Receptor-associated Ca2+ influx is, therefore, likely to be an important route for Ca2+ influx to the lens. The authors investigated stimulated and passive Ca2+ influx in in situ human lens epithelium. Ca2+ changes in equatorial (E) and central anterior (CA) epithelial cells were monitored with the use of a Ca2+ indicator (Fluo4) and confocal microscopy. Gene expression was monitored by RT-PCR and immunoblotting. Adenosine triphosphate (ATP) induced Ca2+ responses that were smaller in CA than E. Ca2+ store depletion, using ATP (100 ”M) or thapsigargin (1 ”M), revealed greater relative store capacity and Ca2+ influx in E. Ca2+ influx was blocked by La3+ (0.5 ”M) in both regions. Unstimulated Ca2+ influx was greater in E than CA. Greater expression of Orai1 and STIM1 was detected in E than in CA. Greater Ca2+ store capacity and Ca2+ influx in E compared with CA reflects underlying differences in proliferation and differentiation between the regions. The relatively small resting Ca2+ influx in CA epithelium suggests that store-operated Ca2+ entry (SOCE) is the main route of Ca2+ influx in these cells. Greater resting influx and SOCE in E cells suggests that these are a major route for Ca2+ influx into the lens. Increased expression of Orai1 and STIM1 in E could account for the differences in Ca2+ entry. Receptor activation will modulate Ca2+ influx, and inappropriate activity may contribute to cortical cataract
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Development of a Rooftop Collaborative Experimental Space through Experiential Learning Projects
The Solar, Water, Energy, and Thermal Laboratory
(SWEAT Lab) is a rooftop experimental space at the
University of Texas at Austin built by graduate and
undergraduate students in the Cockrell School of
Engineering. The project was funded by the Texas State
Energy Conservation Office and the Universityâs Green
Fee Grant, a competitive grant program funded by UT
Austin tuition fees to support sustainability-related projects
and initiatives on campus. The SWEAT Lab is an on-going
experiential learning facility that enables engineering
education by deploying energy and water-related projects.
To date, the lab contains a full weather station tracking
weather data, a rainwater harvesting system and rooftop
garden.
This project presented many opportunities for students to
learn first hand about unique engineering challenges. The
lab is located on the roof of the 10 story Engineering
Teaching Center (ETC) building, so students had to design
and build systems with constraints such as weight
limitations and wind resistance. Students also gained
experience working with building facilities and
management for structural additions, power, and internet
connection for instruments.
With the Birdâs eye view of UT Austin campus, this unique
laboratory offers a new perspective and dimension to
applied student research projects at UT Austin.Cockrell School of Engineerin
Optimal timing for power plant maintenance in the Electricity Reliability Council of Texas in a changing climate
We analyzed data for the Electricity Reliability Council of Texas (ERCOT) to
assess shoulder seasons -- that is, the 45 days of lowest total energy use and
peak demand in the spring and fall -- and whether their occurrence has changed
over time. Over the period 1996--2022, the shoulder seasons never started
earlier than late March nor later than mid-October, corresponding well with the
minimum of total degree days. In the temperature record 1959--2022, the minimum
in degree days in the spring moved earlier, from early March to early February,
and in the fall moved later, from early to mid-November. Warming temperatures
might cause these minima in degree days to merge into a single annual minimum
in December or January by the mid-2040s, a time when there is a non-trivial
risk of 1-day record energy use and peak demand from winter storms
Markov Chain Monte Carlo Optimization applied to Dyson's Visual Double Stars
Estimates of orbital parameters were made using a Bayesian optimization
technique on astrometric data for 25 visual binary systems catalogued a century
ago by the ninth Astronomer Royal, Sir Frank Dyson. An advantage of this method
is that it provides reliable, unbiased uncertainty estimates for the optimized
parameters. Reasonable agreement is found for the short period (< 100 yr)
systems between the current study and Dyson, with superior estimation for the
longer systems through the inclusion of an additional century of data.
Dynamical masses are presented for the systems through the inclusion of
parallax measurements.Comment: 15 pages, 6 figures, 3 tables. Accepted by JAAVS
Information scraps: how and why information eludes our personal information management tools
In this paper we describe information scraps -- a class of personal information whose content is scribbled on Post-it notes, scrawled on corners of random sheets of paper, buried inside the bodies of e-mail messages sent to ourselves, or typed haphazardly into text files. Information scraps hold our great ideas, sketches, notes, reminders, driving directions, and even our poetry. We define information scraps to be the body of personal information that is held outside of its natural or We have much still to learn about these loose forms of information capture. Why are they so often held outside of our traditional PIM locations and instead on Post-its or in text files? Why must we sometimes go around our traditional PIM applications to hold on to our scraps, such as by e-mailing ourselves? What are information scraps' role in the larger space of personal information management, and what do they uniquely offer that we find so appealing? If these unorganized bits truly indicate the failure of our PIM tools, how might we begin to build better tools? We have pursued these questions by undertaking a study of 27 knowledge workers. In our findings we describe information scraps from several angles: their content, their location, and the factors that lead to their use, which we identify as ease of capture, flexibility of content and organization, and avilability at the time of need. We also consider the personal emotive responses around scrap management. We present a set of design considerations that we have derived from the analysis of our study results. We present our work on an application platform, jourknow, to test some of these design and usability findings
Submarine radial vents on Mauna Loa Volcano, Hawai'i
A 2002 multibeam sonar survey of Mauna Loa's western flank revealed ten submarine radial vents and three submarine lava flows. Only one submarine radial vent was known previously. The ages of these vents are constrained by eyewitness accounts, geologic relationships, Mn-Fe coatings, and geochemical stratigraphy; they range from 128 years B.P. to possibly 47 ka. Eight of the radial vents produced degassed lavas despite eruption in water depths sufficient to inhibit sulfur degassing. These vents formed truncated cones and short lava flows. Two vents produced undegassed lavas that created ''irregular'' cones and longer lava flows. Compositionally and isotopically, the submarine radial vent lavas are typical of Mauna Loa lavas, except two cones that erupted alkalic lavas. He-Sr isotopes for the radial vent lavas follow Mauna Loa's evolutionary trend. The compositional and isotopic heterogeneity of these lavas indicates most had distinct parental magmas. Bathymetry and acoustic backscatter results, along with photography and sampling during four JASON2 dives, are used to produce a detailed geologic map to evaluate Mauna Loa's submarine geologic history. The new map shows that the 1877 submarine eruption was much larger than previously thought, resulting in a 10% increase for recent volcanism. Furthermore, although alkalic lavas were found at two radial vents, there is no systematic increase in alkalinity among these or other Mauna Loa lavas as expected for a dying volcano. These results refute an interpretation that Mauna Loa's volcanism is waning. The submarine radial vents and flows cover 29 km 2 of seafloor and comprise a total volume of âŒ2 Ă 10 9 m3 of lava, reinforcing the idea that submarine lava eruptions are important in the growth of oceanic island volcanoes even after they emerged above sea level
The enigmatic multiple star VV Ori
New photometry, including TESS data, have been combined with recent
spectroscopic observations of the Orion Ib pulsating triple-star system VV Ori.
This yields a revised set of absolute parameters with increased precision. Two
different programs were utilized for the light curve analysis, with results in
predictably close agreement. The agreement promotes confidence in the analysis
procedures. The spectra were analysed using the {\sc FDBinary} program. The
main parameters are as follows: and
(M). We estimate an approximate mass of the wide companion as M. Similarly, , , (R); , and (K). The close
binary's orbital separation is (R); its age is
(Myr) and its photometric distance is pc. The primary's Cep
type oscillations support these properties and confirm our understanding of its
evolutionary status. Examination of the well-defined 6678 He I
profiles reveals the primary to have a significantly low projected rotation:
some 80\% of the synchronous value. This can be explained on the basis of the
precession of an unaligned spin axis. This proposal can resolve also observed
variations of the apparent inclination and address other longer-term
irregularities of the system reported in the literature. This topic invites
further observations and follow-up theoretical study of the dynamics of this
intriguing young multiple star.Comment: 17 pages, 15 figures, 14 tables, accepted by MNRA
Spermatozoan numbers and testicular characteristics of male white-tailed deer fawns during the mating season
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