246 research outputs found
Search for Large Extra Dimensions at the Tevatron
We report a search for large extra spatial dimensions in
collisions at a center of mass energy of 1.8 TeV at the Tevatron. We present
recent D0 results on graviton-mediated exchange processes, using events
containing a pair of electrons or photons. No evidence for signal is found,
allowing to place the most restrictive lower limits on the effective Planck
scale at the order of 1 TeV for several number of extra dimensions.Comment: 4 pages, 3 figures. Invited talk at 36th Rencontres de Moriond on QCD
and Hadronic Interactions, Les Arcs, France, 17-24 Mar 2001 (to appear in the
Proceedings). Transparencies for this talk are available from
http://moriond.in2p3.f
Dual Queue Coupled AQM: Deployable Very Low Queuing Delay for All
On the Internet, sub-millisecond queueing delay and capacity-seeking have
traditionally been considered mutually exclusive. We introduce a service that
offers both: Low Latency Low Loss Scalable throughput (L4S). When tested under
a wide range of conditions emulated on a testbed using real residential
broadband equipment, queue delay remained both low (median 100--300 s) and
consistent (99th percentile below 2 ms even under highly dynamic workloads),
without compromising other metrics (zero congestion loss and close to full
utilization). L4S exploits the properties of `Scalable' congestion controls
(e.g., DCTCP, TCP Prague). Flows using such congestion control are however very
aggressive, which causes a deployment challenge as L4S has to coexist with
so-called `Classic' flows (e.g., Reno, CUBIC). This paper introduces an
architectural solution: `Dual Queue Coupled Active Queue Management', which
enables balance between Scalable and Classic flows. It counterbalances the more
aggressive response of Scalable flows with more aggressive marking, without
having to inspect flow identifiers. The Dual Queue structure has been
implemented as a Linux queuing discipline. It acts like a semi-permeable
membrane, isolating the latency of Scalable and `Classic' traffic, but coupling
their capacity into a single bandwidth pool. This paper justifies the design
and implementation choices, and visualizes a representative selection of
hundreds of thousands of experiment runs to test our claims.Comment: Preprint. 17pp, 12 Figs, 60 refs. Submitted to IEEE/ACM Transactions
on Networkin
Determination of uromodulin in human urine: influence of storage and processing
Background Uromodulin (Tamm-Horsfall protein) is the most abundant protein excreted in the urine under physiological conditions. It is exclusively produced in the kidney and secreted into the urine via proteolytic cleavage. The involvement of UMOD, the gene that encodes uromodulin, in rare autosomal dominant diseases, and its robust genome-wide association with the risk of chronic kidney disease suggest that the level of uromodulin in urine could represent a critical biomarker for kidney function. The structure of uromodulin is complex, with multiple disulfide bonds and typical domains of extracellular proteins. Methods Thus far, the conditions influencing stability and measurement of uromodulin in human urine have not been systematically investigated, giving inconsistent results. In this study, we used a robust, in-house ELISA to characterize the conditions of sampling and storage necessary to provide a faithful dosage of uromodulin in the urine. Results The levels of uromodulin in human urine were significantly affected by centrifugation and vortexing, as well as by the conditions and duration of storage. Conclusions These results validate a simple, low-cost ELISA and document the optimal conditions of processing and storage for measuring uromodulin in human urin
Dependency structure matrix modelling for stakeholder value networks
This paper develops a qualitative/quantitative network approach, namely a âStakeholder Value Networkâ, to understand the impacts of both direct and indirect relationships between stakeholders on the success of large engineering projects. Specifically, this paper explores the feasibility and benefit of applying the Dependency Structure Matrix (DSM) as the modelling platform for Stakeholder Value Networks. Further, an efficient algorithm is designed for computing indirect stakeholder influence and implemented in a case study for a multinational energy project. The results derived from this analysis are able to answer three fundamental questions for stakeholder management: What are the critical paths/themes for a project to engage other stakeholders? Who are the most important stakeholders for a project? How can the complexity of a large relationship network be reasonably managed
Comment on "Evidence for dark matter in the inner Milky Way"
This is a brief rebuttal to arXiv:1502.03821, which claims to provide the
first observational proof of dark matter interior to the solar circle. We point
out that this result is not new, and can be traced back at least a quarter
century.Comment: 3 pages, 2 figures. In this version we add a figure from a 1998 paper
that shows the same result that arXiv:1502.03821 claims to be novel. We also
add a short note rebutting arXiv:1503.08784 which was written in response to
the first versio
A primary culture system of mouse thick ascending limb cells with preserved function and uromodulin processing
The epithelial cells lining the thick ascending limb (TAL) of the loop of Henle perform essential transport processes and secrete uromodulin, the most abundant protein in normal urine. The lack of differentiated cell culture systems has hampered studies of TAL functions. Here, we report a method to generate differentiated primary cultures of TAL cells, developed from microdissected tubules obtained in mouse kidneys. The TAL tubules cultured on permeable filters formed polarized confluent monolayers in âŒ12days. The TAL cells remain differentiated and express functional markers such as uromodulin, NKCC2, and ROMK at the apical membrane. Electrophysiological measurements on primary TAL monolayers showed a lumen-positive transepithelial potential (+9.4â±â0.8mV/cm2) and transepithelial resistance similar to that recorded in vivo. The transepithelial potential is abolished by apical bumetanide and in primary cultures obtained from ROMK knockout mice. The processing, maturation and apical secretion of uromodulin by primary TAL cells is identical to that observed in vivo. The primary TAL cells respond appropriately to hypoxia, hypertonicity, and stimulation by desmopressin, and they can be transfected. The establishment of this primary culture system will allow the investigation of TAL cells obtained from genetically modified mouse models, providing a critical tool for understanding the role of that segment in health and disease
On the alleged simplicity of impure proof
Roughly, a proof of a theorem, is âpureâ if it draws only on what is âcloseâ or âintrinsicâ to that theorem. Mathematicians employ a variety of terms to identify pure proofs, saying that a pure proof is one that avoids what is âextrinsic,â âextraneous,â âdistant,â âremote,â âalien,â or âforeignâ to the problem or theorem under investigation. In the background of these attributions is the view that there is a distance measure (or a variety of such measures) between mathematical statements and proofs. Mathematicians have paid little attention to specifying such distance measures precisely because in practice certain methods of proof have seemed self- evidently impure by design: think for instance of analytic geometry and analytic number theory. By contrast, mathematicians have paid considerable attention to whether such impurities are a good thing or to be avoided, and some have claimed that they are valuable because generally impure proofs are simpler than pure proofs. This article is an investigation of this claim, formulated more precisely by proof- theoretic means. After assembling evidence from proof theory that may be thought to support this claim, we will argue that on the contrary this evidence does not support the claim
Supporting stimulation needs in dementia care through wall-sized displays
Beside reminiscing, the increasing cognitive decline in dementia can also be addressed through sensory stimulation allowing the immediate, nonverbal engagement with the world through oneâs senses. Much HCI work has prioritized cognitive stimulation for reminiscing or personhood often on small screens, while less research has explored sensory stimulation like the one enabled by large displays. We describe a year-long deployment in a residential care home of a wall-sized display, and explored its domestication through 24 contextual interviews. Findings indicate strong engagement and attachment to the display which has inspired four psychosocial interventions using online generic content. We discuss the value of these findings for personhood through residentsâ exercise of choices, the tension between generic/personal content and its public/private use, the importance of participatory research approach to domestication, and the infrastructure-based prototype, illustrated by the DementiaWall and its generative quality
LSST: from Science Drivers to Reference Design and Anticipated Data Products
(Abridged) We describe here the most ambitious survey currently planned in
the optical, the Large Synoptic Survey Telescope (LSST). A vast array of
science will be enabled by a single wide-deep-fast sky survey, and LSST will
have unique survey capability in the faint time domain. The LSST design is
driven by four main science themes: probing dark energy and dark matter, taking
an inventory of the Solar System, exploring the transient optical sky, and
mapping the Milky Way. LSST will be a wide-field ground-based system sited at
Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m
effective) primary mirror, a 9.6 deg field of view, and a 3.2 Gigapixel
camera. The standard observing sequence will consist of pairs of 15-second
exposures in a given field, with two such visits in each pointing in a given
night. With these repeats, the LSST system is capable of imaging about 10,000
square degrees of sky in a single filter in three nights. The typical 5
point-source depth in a single visit in will be (AB). The
project is in the construction phase and will begin regular survey operations
by 2022. The survey area will be contained within 30,000 deg with
, and will be imaged multiple times in six bands, ,
covering the wavelength range 320--1050 nm. About 90\% of the observing time
will be devoted to a deep-wide-fast survey mode which will uniformly observe a
18,000 deg region about 800 times (summed over all six bands) during the
anticipated 10 years of operations, and yield a coadded map to . The
remaining 10\% of the observing time will be allocated to projects such as a
Very Deep and Fast time domain survey. The goal is to make LSST data products,
including a relational database of about 32 trillion observations of 40 billion
objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures
available from https://www.lsst.org/overvie
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