68,090 research outputs found
Guide to cataloging slotMusic based on AACR2 Chapters 6 and 9
In September 2008 SanDisk announced it would begin making music available for purchase on its microSD flash memory card format.1 The audio files on a slotMusic card are in MP3 format and are offered free of any digital rights management controls. In addition to containing an album\u27s worth of music (i.e., a slotMusic release generally corresponds to a collection of music issued on other formats such as compact disc), a typical slotMusic card may come pre-loaded with images, video, text, MIDI files, etc. Each card contains 1 GB of memory (well more than what is required for the pre-loaded content) and the extra memory can be used in whatever way the buyer wishes. Indeed, the preloaded content can be moved to another storage device and the memory card can be formatted and used like any other card.
Music on slotMusic cards can be accessed using any device that both accepts microSD cards and is able to play MP3 files at up to 320 kbps.2 In addition, some slotMusic cards come packaged with a special microSD-to-USB adapter, which makes it possible to load slotMusic content onto a computer, car stereo, or any other device equipped with a USB jack. Some slotMusic cards are also sold as bundles, which in addition to the memory card and USB adapter include special dedicated MP3 players that accept the microSD format.
Many early media responses questioned whether there would be a market for slotMusic, reasoning that music consumers interested in MP3s generally are comfortable with downloading them through computer network connections.3 But a more recent report in the Los Angeles Times argues that the format is doing better than many expected.4 Still, in April 2010, a search for “slotmusic” in WorldCat retrieves only the record created by this task force as an example, and it is unclear whether any libraries have begun collecting this new format.
In terms of cataloging, slotMusic offers a number of challenges. Like much electronic media, the cards exhibit aspects of more than one format, in this case at least sound recordings and electronic resources. Currently, and as the name implies, slotMusic only offers musical sound recordings, but future releases could potentially contain non-musical sound. SlotMusic releases contain no descriptive information on the card itself, making choice of chief sources of information challenging. And slotMusic releases often come bundled with peripheral items (such as USB adapters and MP3 players) that contain no intellectual content, making for interesting accompanying materials notes. And finally, since the devices that can play the cards are numerous, but the technical requirements of those devices are complex, clear notes regarding the playback characteristics of the cards are necessary
Optical Coherence Tomography Angiography Vessel Density in Healthy, Glaucoma Suspect, and Glaucoma Eyes.
PurposeThe purpose of this study was to compare retinal nerve fiber layer (RNFL) thickness and optical coherence tomography angiography (OCT-A) retinal vasculature measurements in healthy, glaucoma suspect, and glaucoma patients.MethodsTwo hundred sixty-one eyes of 164 healthy, glaucoma suspect, and open-angle glaucoma (OAG) participants from the Diagnostic Innovations in Glaucoma Study with good quality OCT-A images were included. Retinal vasculature information was summarized as a vessel density map and as vessel density (%), which is the proportion of flowing vessel area over the total area evaluated. Two vessel density measurements extracted from the RNFL were analyzed: (1) circumpapillary vessel density (cpVD) measured in a 750-μm-wide elliptical annulus around the disc and (2) whole image vessel density (wiVD) measured over the entire image. Areas under the receiver operating characteristic curves (AUROC) were used to evaluate diagnostic accuracy.ResultsAge-adjusted mean vessel density was significantly lower in OAG eyes compared with glaucoma suspects and healthy eyes. (cpVD: 55.1 ± 7%, 60.3 ± 5%, and 64.2 ± 3%, respectively; P < 0.001; and wiVD: 46.2 ± 6%, 51.3 ± 5%, and 56.6 ± 3%, respectively; P < 0.001). For differentiating between glaucoma and healthy eyes, the age-adjusted AUROC was highest for wiVD (0.94), followed by RNFL thickness (0.92) and cpVD (0.83). The AUROCs for differentiating between healthy and glaucoma suspect eyes were highest for wiVD (0.70), followed by cpVD (0.65) and RNFL thickness (0.65).ConclusionsOptical coherence tomography angiography vessel density had similar diagnostic accuracy to RNFL thickness measurements for differentiating between healthy and glaucoma eyes. These results suggest that OCT-A measurements reflect damage to tissues relevant to the pathophysiology of OAG
Survival of icy grains in debris discs. The role of photosputtering
We put theoretical constraints on the presence and survival of icy grains in
debris discs. Particular attention is paid to UV sputtering of water ice, which
has so far not been studied in detail in this context. We present a
photosputtering model based on available experimental and theoretical studies.
We quantitatively estimate the erosion rate of icy and ice-silicate grains,
under the influence of both sublimation and photosputtering, as a function of
grain size, composition and distance from the star. The effect of erosion on
the grain's location is investigated through numerical simulations coupling the
grain size to its dynamical evolution. Our model predicts that photodesorption
efficiently destroy ice in optically thin discs, even far beyond the
sublimation snow line. For the reference case of beta Pictoris, we find that
only > 5mm grains can keep their icy component for the age of the system in the
50-150AU region. When taking into account the collisional reprocessing of
grains, we show that the water ice survival on grains improves (grains down to
~ 20 um might be partially icy). However, estimates of the amount of gas
photosputtering would produce on such a hypothetical population of big icy
grains lead to values for the OI column density that strongly exceed
observational constraints for beta Pic, thus ruling out the presence of a
significant amount of icy grains in this system. Erosion rates and icy grains
survival timescales are also given for a set of 11 other debris disc systems.
We show that, with the possible exception of M stars, photosputtering cannot be
neglected in calculations of icy grain lifetimes.Comment: 12 pages, 9 figures. accepted by A&
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The Relative Odds of Progressing by Structural and Functional Tests in Glaucoma.
PurposeThe purpose of this study was to evaluate the effect of disease severity and number of tests acquired during follow-up on the relative odds of identifying progression by structural or functional tests in glaucoma.MethodsThis was an observational cohort study involving 462 eyes of 305 patients with glaucoma and 62 eyes of 49 healthy subjects. Glaucoma patients and healthy subjects were followed for an average of 3.6 ± 0.9 and 3.8 ± 0.9 years, with a median (interquantile range) of 8 (6-9) and 7 (6-8) visits, respectively. At each visit, subjects underwent visual field assessment with standard automated perimetry (SAP) and retinal nerve fiber layer (RNFL) evaluation by spectral-domain optical coherence tomography (SD-OCT). Slopes of change in SAP mean sensitivity and OCT RNFL thickness over time were estimated by linear regression using progressively cumulative visits over time. Cutoff values for age-related expected rates of change for each test were obtained from the healthy group. Progression by SD-OCT and/or SAP was determined if the slope of change was statistically significant and also lower (faster) than the fifth percentile cutoff calculated from the healthy group. A generalized estimating equation logistic regression model was used to evaluate the relative odds of progressing by OCT versus SAP in glaucoma eyes.ResultsEyes with less severe disease at baseline had a higher chance of being detected as progressing by SD-OCT but not by SAP, whereas an increase in disease severity at baseline increased the chance that the eye would be detected as progressing by SAP but not SD-OCT. Each 1 dB higher MD was associated with a 5% increase in the odds of detecting progression by SD-OCT versus SAP (odds ratio = 1.05 per 1 dB; 95% confidence interval: 1.01-1.09; P = 0.005).ConclusionsThe ability to detect glaucoma progression by SAP versus SD-OCT is significantly influenced by the stage of disease. Our results may provide useful information for guiding clinicians on the relative utility of these tests for detecting change throughout the disease continuum
The Architectural Design Rules of Solar Systems based on the New Perspective
On the basis of the Lunar Laser Ranging Data released by NASA on the Silver
Jubilee Celebration of Man Landing on Moon on 21st July 1969-1994, theoretical
formulation of Earth-Moon tidal interaction was carried out and Planetary
Satellite Dynamics was established. It was found that this mathematical
analysis could as well be applied to Star and Planets system and since every
star could potentially contain an extra-solar system, hence we have a large
ensemble of exoplanets to test our new perspective on the birth and evolution
of solar systems. Till date 403 exoplanets have been discovered in 390
extra-solar systems. I have taken 12 single planet systems, 4 Brown Dwarf -
Star systems and 2 Brown Dwarf pairs. Following architectural design rules are
corroborated through this study of exoplanets. All planets are born at inner
Clarke Orbit what we refer to as inner geo-synchronous orbit in case of
Earth-Moon System. By any perturbative force such as cosmic particles or
radiation pressure, the planet gets tipped long of aG1 or short of aG1. Here
aG1 is inner Clarke Orbit. The exoplanet can either be launched on death spiral
as CLOSE HOT JUPITERS or can be launched on an expanding spiral path as the
planets in our Solar System are. It was also found that if the exo-planet are
significant fraction of the host star then those exo-planets rapidly migrate
from aG1 to aG2 and have very short Time Constant of Evolution as Brown Dwarfs
have. This vindicates our basic premise that planets are always born at inner
Clarke Orbit. This study vindicates the design rules which had been postulated
at 35th COSPAR Scientific Assembly in 2004 at Paris, France, under the title
,New Perspective on the Birth & Evolution of Solar Systems.Comment: This paper has been reported to Earth,Moon and Planets Journal as
MOON-S-09-0007
Hybrid methods in planetesimal dynamics: Formation of protoplanetary systems and the mill condition
The formation and evolution of protoplanetary discs remains a challenge from
both a theoretical and numerical standpoint. In this work we first perform a
series of tests of our new hybrid algorithm presented in Glaschke, Amaro-Seoane
and Spurzem 2011 (henceforth Paper I) that combines the advantages of high
accuracy of direct-summation N-body methods with a statistical description for
the planetesimal disc based on Fokker-Planck techniques. We then address the
formation of planets, with a focus on the formation of protoplanets out of
planetesimals. We find that the evolution of the system is driven by encounters
as well as direct collisions and requires a careful modelling of the evolution
of the velocity dispersion and the size distribution over a large range of
sizes. The simulations show no termination of the protoplanetary accretion due
to gap formation, since the distribution of the planetesimals is only subjected
to small fluctuations. We also show that these features are weakly correlated
with the positions of the protoplanets. The exploration of different impact
strengths indicates that fragmentation mainly controls the overall mass loss,
which is less pronounced during the early runaway growth. We prove that the
fragmentation in combination with the effective removal of collisional
fragments by gas drag sets an universal upper limit of the protoplanetary mass
as a function of the distance to the host star, which we refer to as the mill
condition.Comment: Submitte
Structural Change Can Be Detected in Advanced-Glaucoma Eyes.
PurposeTo compare spectral-domain optical coherence tomography (SD-OCT) standard structural measures and a new three-dimensional (3D) volume optic nerve head (ONH) change detection method for detecting change over time in severely advanced-glaucoma (open-angle glaucoma [OAG]) patients.MethodsThirty-five eyes of 35 patients with very advanced glaucoma (defined as a visual field mean deviation < -21 dB) and 46 eyes of 30 healthy subjects to estimate aging changes were included. Circumpapillary retinal fiber layer thickness (cpRNFL), minimum rim width (MRW), and macular retinal ganglion cell-inner plexiform layer (GCIPL) thicknesses were measured using the San Diego Automated Layer Segmentation Algorithm (SALSA). Progression was defined as structural loss faster than 95th percentile of healthy eyes. Three-dimensional volume ONH change was estimated using the Bayesian-kernel detection scheme (BKDS), which does not require extensive retinal layer segmentation.ResultsThe number of progressing glaucoma eyes identified was highest for 3D volume BKDS (13, 37%), followed by GCPIL (11, 31%), cpRNFL (4, 11%), and MRW (2, 6%). In advanced-OAG eyes, only the mean rate of GCIPL change reached statistical significance, -0.18 μm/y (P = 0.02); the mean rates of cpRNFL and MRW change were not statistically different from zero. In healthy eyes, the mean rates of cpRNFL, MRW, and GCIPL change were significantly different from zero. (all P < 0.001).ConclusionsGanglion cell-inner plexiform layer and 3D volume BKDS show promise for identifying change in severely advanced glaucoma. These results suggest that structural change can be detected in very advanced disease. Longer follow-up is needed to determine whether changes identified are false positives or true progression
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