2,077 research outputs found
Invest to Save: Report and Recommendations of the NSF-DELOS Working Group on Digital Archiving and Preservation
Digital archiving and preservation are important areas for research and development, but there is no agreed upon set of priorities or coherent plan for research in this area. Research projects in this area tend to be small and driven by particular institutional problems or concerns. As a consequence, proposed solutions from experimental projects and prototypes tend not to scale to millions of digital objects, nor do the results from disparate projects readily build on each other. It is also unclear whether it is worthwhile to seek general solutions or whether different strategies are needed for different types of digital objects and collections. The lack of coordination in both research and development means that there are some areas where researchers are reinventing the wheel while other areas are neglected.
Digital archiving and preservation is an area that will benefit from an exercise in analysis, priority setting, and planning for future research. The WG aims to survey current research activities, identify gaps, and develop a white paper proposing future research directions in the area of digital preservation. Some of the potential areas for research include repository architectures and inter-operability among digital archives; automated tools for capture, ingest, and normalization of digital objects; and harmonization of preservation formats and metadata. There can also be opportunities for development of commercial products in the areas of mass storage systems, repositories and repository management systems, and data management software and tools.
Trajectories of Alcohol Use and Consequences in College Women with and without Depressed Mood
College students with depressed mood face heightened risk for experiencing drinking-related negative consequences. However, few studies have examined prospective patterns of alcohol consequences among depressed students. In the present investigation, we assessed how first-year college women’s trajectories of heavy episodic drinking (HED) and alcohol consequences differed as a function of depressed mood at college entry. Participants were 233 heavy drinking incoming first-year college females (61% White) at a mid-sized west coast university. Participants completed an online baseline survey, attended a single brief group intervention session, and completed 1- and 6-month post-intervention follow-up surveys. Depressed mood, alcohol consumption, and alcohol consequences were assessed at each time point. We employed latent growth curve analyses. Females with depressed mood, versus without depressed mood, experienced greater levels of alcohol consequences overall, particularly during transitions to college. However, contrary to hypotheses, participants with depressed mood (vs. without) exhibited significantly steeper declining trends in consequences, controlling for treatment condition, age, race, and ethnicity, and despite stable drinking levels, depressed mood, and use of protective behaviors over time. Potential explanations and suggestions for future research are discussed
Temporal variability and statistics of the Strehl ratio in adaptive-optics images
We have investigated the temporal variability and statistics of the
"instantaneous" Strehl ratio. The observations were carried out with the 3.63-m
AEOS telescope equipped with a high-order adaptive optics system. In this paper
Strehl ratio is defined as the peak intensity of a single short exposure. We
have also studied the behaviour of the phase variance computed on the
reconstructed wavefronts. We tested the Marechal approximation and used it to
explain the observed negative skewness of the Strehl ratio distribution. The
estimate of the phase variance is shown to fit a three-parameter Gamma
distribution model. We show that simple scaling of the reconstructed wavefronts
has a large impact on the shape of the Strehl ratio distribution.Comment: submitted to PAS
Spectacular X-ray tails, intracluster star formation and ULXs in A3627
We present the discovery of spectacular double X-ray tails associated with
ESO137-001 and a possibly heated X-ray tail associated with ESO137-002, both
late-type galaxies in the closest rich cluster Abell 3627. A deep Chandra
observation of ESO137-001 allows us for the first time to examine the spatial
and spectral properties of such X-ray tails in detail. Besides the known bright
tail that extends to ~ 80 kpc from ESO137-001, a fainter and narrower secondary
tail with a similar length was surprisingly revealed. There is little
temperature variation along both tails. We also identified six X-ray point
sources as candidates of intracluster ULXs with L(0.3-10 keV) of up to
2.5x10^40 erg s^-1. Gemini spectra of intracluster HII regions downstream of
ESO137-001 are also presented, as well as the velocity map of these HII regions
that shows the imprint of ESO137-001's disk rotation. For the first time, we
unambiguously know that active star formation can happen in the cold ISM
stripped by ICM ram pressure and it may contribute a significant amount of the
intracluster light. We also report the discovery of a 40 kpc X-ray tail of
another late-type galaxy in A3627, ESO137-002. Its X-ray tail seems hot, ~ 2
keV (compared to ~ 0.8 keV for ESO137-001's tails). We conclude that the high
pressure environment around these two galaxies is important for their bright
X-ray tails and the intracluster star formation.Comment: ApJ in press, January 2010, v708, only several minor word changes,
emulateapj5.sty, 24 pages, 11 color + 5 B/W figures (figure quality degraded)
and 4 tables. The abstract has been abbreviated. A high-resolution PDF is
available at: http://www.astro.virginia.edu/~ms4ar/eso137_p3.pd
NGC 4569: recent evidence for a past ram pressure stripping event
Deep 21-cm HI line observations of the Virgo cluster spiral galaxy NGC 4569
have been obtained with the VLA in its D configuration and with the Effelsberg
100-m telescope. A low surface density arm was discovered in the west of the
galaxy, whose velocity field is distinct from that of the overall disk
rotation. The observed gas distribution, velocity field, and velocity
dispersion are compared to snapshots of dynamical simulations that include the
effects of ram pressure. Two different scenarios were explored: (i) ongoing
stripping and (ii) a major stripping event that took place about 300 Myr ago.
It is concluded that only the post-stripping scenario can reproduce the main
observed characteristics of NGC 4569. It is not possible to determine if the
gas disk of NGC 4569 had already been truncated before it underwent the ram
pressure event that lead to its observed HI deficiency.Comment: 13 pages, 15 figures. Accepted for publication in A&
Parallel suppression of superconductivity and Fe moment in the collapsed tetragonal phase of Ca0.67Sr0.33Fe2As2 under pressure
Using non-resonant Fe K-beta x-ray emission spectroscopy, we reveal that
Sr-doping of CaFe2As2 decouples the Fe moment from the volume collapse
transition, yielding a collapsed-tetragonal, paramagnetic normal state out of
which superconductivity develops. X-ray diffraction measurements implicate the
c-axis lattice parameter as the controlling criterion for the Fe moment,
promoting a generic description for the appearance of pressure-induced
superconductivity in the alkaline-earth-based 122 ferropnictides (AFe2As2). The
evolution of the superconducting critical temperature with pressure lends
support to theories for superconductivity involving unconventional pairing
mediated by magnetic fluctuations
Tetrabenazine as anti-chorea therapy in Huntington Disease: an open-label continuation study. Huntington Study Group/TETRA-HD Investigators
<p>Abstract</p> <p>Background</p> <p>Tetrabenazine (TBZ) selectively depletes central monoamines by reversibly binding to the type-2 vesicular monoamine transporter. A previous double blind study in Huntington disease (HD) demonstrated that TBZ effectively suppressed chorea, with a favorable short-term safety profile (<it>Neurology </it>2006;66:366-372). The objective of this study was to assess the long-term safety and effectiveness of TBZ for chorea in HD.</p> <p>Methods</p> <p>Subjects who completed the 13-week, double blind protocol were invited to participate in this open label extension study for up to 80 weeks. Subjects were titrated to the best individual dose or a maximum of 200 mg/day. Chorea was assessed using the Total Maximal Chorea (TMC) score from the Unified Huntington Disease Rating Scale.</p> <p>Results</p> <p>Of the 75 participants, 45 subjects completed 80 weeks. Three participants terminated due to adverse events (AEs) including depression, delusions with associated previous suicidal behavior, and vocal tics. One subject died due to breast cancer. The other 26 subjects chose not to continue on with each ensuing extension for various reasons. When mild and unrelated AEs were excluded, the most commonly reported AEs (number of subjects) were sedation/somnolence (18), depressed mood (17), anxiety (13), insomnia (10), and akathisia (9). Parkinsonism and dysphagia scores were significantly increased at week 80 compared to baseline. At week 80, chorea had significantly improved from baseline with a mean reduction in the TMC score of 4.6 (SD 5.5) units. The mean dosage at week 80 was 63.4 mg (range 12.5-175 mg).</p> <p>Conclusions</p> <p>TBZ effectively suppresses HD-related chorea for up to 80 weeks. Patients treated chronically with TBZ should be monitored for parkinsonism, dysphagia and other side effects including sleep disturbance, depression, anxiety, and akathisia.</p> <p>Trial Registration</p> <p>Clinicaltrials.gov registration number (initial study): NCT00219804</p
Indicated biological effect from the 9 July 1962 high altitude nuclear test
An influence of the 9 July 1962 high altitude nuclear test on the reproductive responses in DROSOPHILA cultures was indicated by the occurrence of simultaneous minimas in progeny curves. Progeny from cultures grown in magnetic fields disclosed less deviation from a four generation mean value than did progeny from control cultures. It is suggested that the magnetic fields deflected a portion of the increased 9 July radiation from the test region. Based on limited data,the possibility exists that a protective effect may have been transferred to first generation flies grown out of the magnetic fields. Ein Einfluss des Kernversuchs in grosser Höhe vom 9.Juli 1962 auf die Reaktion von DROSOPHILA-Kulturen wurde durch das Vorkommen gleichzeitiger Minimas in den Kurven für die Nachkommenschaft angedeutet. Die Nachkommen aus Kulturen, die in magnetischen Feldern gewachsen waren, zeigten eine geringere Abweichung vom Mittelwert von 4 Generationen als die Nachkommen aus Vergleichskulturen.Es wird vermutet, dass die magnetischen Felder einen Teil der Strahlung vom 9.Juli vom Versuchsgebiet ablenkten. Es besteht die aufgrund begrenzter Daten gewonnene Möglichkeit,dass eine Schutzwirkung auf die erste Generation von Drosophila übertragen worden ist, die ausserhalb der Magnetfelder aufwuchs. Les essais d'explosion atomique effectués à grande altitude le 9 juillet 1962 ont eu des répercussions sur des élevages de DROSOPHILA. On constante en effet des minimums simultanés dans les courbes de descendance. Les descendants provenant d'élevages placés dans un champ magnétique mentrent,en moyenne de 4 générations, une diminution moins marquée que ceux provenant d'élevages de comparaison. On suppose que les champs magnétiques ont fait dévier une partie des radiations du 9 juillet hors du champ d'essais. En se basant sur ces données fragmentaires, on peut admettre la possibilité d'un effet de protection transmis à la première génération des mouches élevées hors des champs magnétiques.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47838/1/484_2005_Article_BF01426847.pd
The SKA Particle Array Prototype: The First Particle Detector at the Murchison Radio-astronomy Observatory
We report on the design, deployment, and first results from a scintillation
detector deployed at the Murchison Radio-astronomy Observatory (MRO). The
detector is a prototype for a larger array -- the Square Kilometre Array
Particle Array (SKAPA) -- planned to allow the radio-detection of cosmic rays
with the Murchison Widefield Array and the low-frequency component of the
Square Kilometre Array. The prototype design has been driven by stringent
limits on radio emissions at the MRO, and to ensure survivability in a desert
environment. Using data taken from Nov.\ 2018 to Feb.\ 2019, we characterize
the detector response while accounting for the effects of temperature
fluctuations, and calibrate the sensitivity of the prototype detector to
through-going muons. This verifies the feasibility of cosmic ray detection at
the MRO. We then estimate the required parameters of a planned array of eight
such detectors to be used to trigger radio observations by the Murchison
Widefield Array.Comment: 17 pages, 14 figures, 3 table
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