281 research outputs found
10402 Abstracts Collection and Executive Summary -- Inter-Vehicular Communication
From October 3 to October 6, 2010, the Dagstuhl Seminar 10402 ``Inter-Vehicular Communication\u27\u27 was held in Schloss Dagstuhl~--~Leibniz Center for Informatics.
During the seminar, several participants presented their current
research, and ongoing work and open problems were discussed. Abstracts of
the presentations given during the seminar
are put together in this paper. The first section
describes the seminar topics and goals in general
Integrated Microreactor for Chemical and Biochemical Applications
A completely integrated microreactor was developed that allows for the processing of very small amounts of chemical solutions. The entire system comprises several pumps and valves arranged in different branches as well as a mixing unit and a reaction chamber. The streaming path of each branch contains two valves and one pump each. The pumps are driven by piezoelectric elements mounted on thin glass membranes. Each pump is about 3.5 mm x 3.5 mm x 0.7 mm. A pumping rate up to 25 microliters per hour can be achieved. The operational voltage ranges between 40 and 200 V. A volume stroke up to 1.5 millimeter is achievable from the membrane structures. The valves are designed as passive valves. Sealing is by thin metal films. The dimension of a valve unit is 0.8 x 0.8. 07 mm. The ends of the separate streaming branches are arranged to meet in one point. This point acts as the beginning of a mixer unit which contains several fork-shaped channels. The arrangement of these channels allows for the division of the whole liquid stream into partial streams and their reuniting. A homogeneous mixing of solutions and/or gases can be observed after having passed about 10 of the fork elements. A reaction chamber is arranged behind the mixing unit to support the chemical reaction of special fluids. This unit contains heating elements placed outside of the chamber. The complete system is arranged in a modular structure and is built up of silicon. It comprises three silicon wafers bonded together by applying the silicon direct bonding technology. The silicon structures are made only by wet chemical etching processes. The fluid connections to the outside are realized using standard injection needles glued into v-shaped structures on the silicon wafers. It is possible to integrate other components, like sensors or electronic circuits using silicon as the basic material
Popliteal venous thrombosis in juvenile arthritis with Baker cysts: report of 3 cases
Three pediatric patients with different illnesses leading to knee arthritis and large Baker cysts and additional calf swelling are reported. Calf swelling was due to true popliteal venous thrombosis and not to the much more common cause of pseudothrombophlebitis. Careful ultrasound examination can differentiate these two causes of calf swelling. Even though all our patients had risk factors for thrombophilia, we do not recommend routine thrombophilia work-up for all arthritis patients in the absence of thrombosis
Focal Seizures and Posterior Reversible Encephalopathy Syndrome as Presenting Signs of IgA Vasculitis/Henoch-Schoenlein Purpura—An Educative Case and Systematic Review of the Literature
Background: IgA vasculitis/Henoch-Schoenlein purpura (IgAV/HSP) is a systemic small
vessel vasculitis of unknown pathogenesis predominantly affecting children. While skin,
GI tract, joints, and kidneys are frequently affected and considered, central nervous
system (CNS) involvement of this disease is underestimated.
Methods: We provide a case report and systematically review the literature on IgAV,
collecting data on the spectrum of neurological manifestations.
Results: We report on a 7-year-old girl with IgAV who presented with diplopia
and afebrile focal seizures, which preceded the onset of purpura. Cranial magnetic
resonance imaging was consistent with posterior reversible encephalopathy syndrome
(PRES), showing typical focal bilateral parietal swelling and cortical and subcortical high
signal intensities on T2-fluid attenuated inversion recovery (FLAIR) images predominantly
without diffusion restriction. Cerebrospinal fluid analysis and blood tests excluded
systemic inflammation or vasculitis. Interestingly, hypertension was not a hallmark of
the developing disease in the initial phase of PRES manifestation. Renal disease and
other secondary causes for PRES were also excluded. Supportive- and steroid treatment
resulted in restitution ad integrum. Reviewing the literature, we identified 28 other cases of
IgAV with CNS involvement. Severe CNS involvement includes seizures, cerebral edema,
or hemorrhage, as well as PRES. Thirteen patients fulfilled all diagnostic criteria of PRES.
The mean age was 11.2 years (median 8.0, range 5-42 years), with no reported bias
toward gender or ethnic background. Treatment regimens varied from watchful waiting
to oral and intravenously steroids up to plasmapheresis. Three cases showed permanent
CNS impairment.
Conclusion: Collectively, our data demonstrate that (I) severe CNS involvement such
as PRES is an underappreciated feature of IgAV, (II) CNS symptoms may precede other
features of IgAV, (III) PRES can occur in IgAV, and differentiation from CNS vasculitis is
challenging, (IV) pathogenesis of PRES in the context of IgAV remains elusive, which
hampers treatment decisions. We, therefore, conclude that clinical awareness and
the collection of structured data are necessary to elucidate the pathophysiological
connection of IgAV and PRES
The nature of red dwarf galaxies
Using dark matter halos traced by galaxy groups selected from the Sloan
Digital Sky Survey Data Release 4, we find that about 1/4 of the faint galaxies
(\rmag >-17.05, hereafter dwarfs) that are the central galaxies in their own
halo are not blue and star forming, as expected in standard models of galaxy
formation, but are red. In contrast, this fraction is about 1/2 for dwarf
satellite galaxies. Many red dwarf galaxies are physically associated with more
massive halos. In total, about % of red dwarf galaxies reside in
massive halos as satellites, while another % have a spatial
distribution that is much more concentrated towards their nearest massive
haloes than other dwarf galaxies. We use mock catalogs to show that the reddest
population of non-satellite dwarf galaxies are distributed within about 3 times
the virial radii of their nearest massive halos. We suggest that this
population of dwarf galaxies are hosted by low-mass halos that have passed
through their massive neighbors, and that the same environmental effects that
cause satellite galaxies to become red are also responsible for the red colors
of this population of galaxies. We do not find any significant radial
dependence of the population of dwarf galaxies with the highest concentrations,
suggesting that the mechanisms operating on these galaxies affect color more
than structure. However, over 30% of dwarf galaxies are red and isolated and
their origin remains unknown.Comment: 9 pages, 8 figures, Accepted for publication in Ap
V-Edge: Virtual Edge Computing as an Enabler for Novel Microservices and Cooperative Computing
As we move from 5G to 6G, edge computing is one of the concepts that needs
revisiting. Its core idea is still intriguing: instead of sending all data and
tasks from an end user's device to the cloud, possibly covering thousands of
kilometers and introducing delays that are just owed to limited propagation
speed, edge servers deployed in close proximity to the user, e.g., at some 5G
gNB, serve as proxy for the cloud. Yet this promising idea is hampered by the
limited availability of such edge servers. In this paper, we discuss a way
forward, namely the virtual edge computing (V-Edge) concept. V-Edge bridges the
gap between cloud, edge, and fog by virtualizing all available resources
including the end users' devices and making these resources widely available
using well-defined interfaces. V-Edge also acts as an enabler for novel
microservices as well as cooperative computing solutions. We introduce the
general V-Edge architecture and we characterize some of the key research
challenges to overcome, in order to enable wide-spread and even more powerful
edge services
Knowledge and use of HIV pre-exposure prophylaxis among men who have sex with men in Berlin - a multicentre, cross-sectional survey
Background: HIV pre-exposure prophylaxis (PrEP) has likely contributed to large decreases in HIV incidence among men who have sex with men (MSM) in several major cities. Berlin has seen a smaller decline, and affordable PrEP has been accessible through formal channels in Germany only since autumn 2017. We aimed to investigate knowledge and use of PrEP among MSM in Berlin, and factors predictive of a desire to use PrEP and history of PrEP use. Methods: Multicentre, paper-based, self-administered survey of adult MSM whose HIV status was negative or unknown at time of participation. Data were collected from 1 October 2017 to 2 April 2018. Results: 473 of 875 questionnaires were returned (response rate 54.1%; mean age 37.4 years, range 18-79). 90.0% of participants were aware of PrEP and, of these, 48.2% felt well informed about it. Among the 17.2% of participants reporting PrEP use, 59.3% indicated obtaining some or all of it from informal sources. 23.7% of those with no history of PrEP use reported having condomless anal intercourse (CAI) with two or more partners over the past six months. Worries about side effects, cost, not having a doctor who prescribes it, and a lack of information were the most frequently reported barriers to PrEP use. A desire to use PrEP and history of PrEP use were associated in our multivariable model with having multiple CAI partners. A history of PrEP use was associated with having a university degree, one or two parents born outside Germany, or friends living with HIV. Conclusions: We found high awareness of PrEP among MSM in Berlin, but also a strong need for more education on its pros, cons and proper use. The frequency of informal PrEP use was also high, raising urgent individual and public health concerns. Policy makers need to consider recent calls to improve access to PrEP and PrEP education through regular health services
Stellar population gradients in the cores of nearby field E+A galaxies
We have selected a sample of local E+A galaxies from the Sloan Digital Sky
Survey (SDSS) Data Release 7 for follow up integral field spectroscopy with the
Wide Field Spectrograph (WiFeS) on the ANU 2.3-m telescope. The sample was
selected using the Halpha line in place of the [OII]3727 line as the indicator
of on-going star formation (or lack thereof). This allowed us to select a lower
redshift sample of galaxies than available in the literature since the
[OII]3727 falls off the blue end of the wavelength coverage in the SDSS for the
very lowest redshift objects. This low redshift selection means that the
galaxies have a large angular to physical scale which allows us to resolve the
central ~1kpc region of the galaxies; the region where stellar population
gradients are expected. Such observations have been difficult to make using
other higher redshift samples because even at redshifts z~0.1 the angular to
physical scale is similar to the resolution provided by ground based seeing.
Our integral field spectroscopy has enabled us to make the first robust
detections of Balmer line gradients in the centres of E+A galaxies. Six out of
our sample of seven, and all the galaxies with regular morphologies, are
observed to have compact and centrally-concentrated Balmer line absorption.
This is evidence for compact young cores and stellar population gradients which
are predicted from models of mergers and tidal interactions which funnel gas
into the galaxy core. Given the generally isolated nature of our sample this
argues for the galaxies being seen in the late stage of a merger where the
progenitors have already coalesced.Comment: accepted to MNRA
The Cross-Correlation between Galaxies and Groups: Probing the Galaxy Distribution in and around Dark Matter Haloes
We determine the cross-correlation function between galaxies and galaxy
groups, using both the Two-Degree Field Galaxy Redshift Survey (2dFGRS) and the
Sloan Digital Sky Survey (SDSS). We study the cross-correlation as a function
of group mass, and as a function of the luminosity, stellar mass, colour,
spectral type and specific star formation rate of the galaxies. All these
cross-correlation functions show a clear transition from the `1-halo' to the
`2-halo' regimes on a scale comparable to the virial radius of the groups in
consideration. On scales larger than the virial radius, all cross-correlation
functions are roughly parallel, consistent with the linear bias model. In
particular, the large scale correlation amplitudes are higher for more massive
groups, and for brighter and redder galaxies. In the `1-halo' regime, the
cross-correlation function depends strongly on the definition of the group
center. We consider both a luminosity-weighted center (LWC) and a center
defined by the location of the brightest group galaxy (BGC). With the first
definition, the bright early-type galaxies in massive groups are found to be
more centrally concentrated than the fainter, late-type galaxies. Using the
BGC, and excluding the brightest galaxy from the cross correlation analysis, we
only find significant segregation in massive groups (M \gta
10^{13}h^{-1}\msun) for galaxies of different spectral types (or colours or
specific star formation rates). In haloes with masses \la 10^{13}h^{-1}\msun,
there is a significant deficit of bright satellite galaxies. Comparing the
results from the 2dFGRS with those obtained from realistic mock samples, we
find that the distribution of galaxies in groups is much less concentrated than
dark matter haloes predicted by the current CDM model. (Abridged)Comment: 18 pages, 11 figures. Accepted for publication in MNRAS, 1 table
added, fig7 replace
- …