176,843 research outputs found
Structural Antennas for 3cm Radar Onboard Multi-Rotor UAV
A series of 3cm amateur band radar antennas suitable for installation on a cinematic grade multi-rotor UAV were considered. A wideband open waveguide mouth antenna was developed that can be made from the existing arms of a multi-rotor UAV without any increase in weight for side-looking wall detection ranging radar. For downward looking radio altimeter, cutting slots in the arms to form slotted waveguide antennas was shown in simulation to be possible both in terms of covering the entire 3cm band from 10 to 10.5GHz and without overly weakening the arms as structural members
Study of Multi-muon Events from EAS with the L3 Detector at Shallow Depth Underground
We present first preliminary data from the L3+Cosmics experiment and results
from Monte Carlo simulations of multi-muon events as observed 30 m underground.Comment: 3 pages, 2 figures; presented at the 6th International Workshop on
Topics in Astroparticle and Underground Physics, TAUP99, September 6-10,
1999, Paris, Franc
Expressive Stream Reasoning with Laser
An increasing number of use cases require a timely extraction of non-trivial
knowledge from semantically annotated data streams, especially on the Web and
for the Internet of Things (IoT). Often, this extraction requires expressive
reasoning, which is challenging to compute on large streams. We propose Laser,
a new reasoner that supports a pragmatic, non-trivial fragment of the logic
LARS which extends Answer Set Programming (ASP) for streams. At its core, Laser
implements a novel evaluation procedure which annotates formulae to avoid the
re-computation of duplicates at multiple time points. This procedure, combined
with a judicious implementation of the LARS operators, is responsible for
significantly better runtimes than the ones of other state-of-the-art systems
like C-SPARQL and CQELS, or an implementation of LARS which runs on the ASP
solver Clingo. This enables the application of expressive logic-based reasoning
to large streams and opens the door to a wider range of stream reasoning use
cases.Comment: 19 pages, 5 figures. Extended version of accepted paper at ISWC 201
A Case of Hyperkalemia Versus Pseudohyperkalemia in Chronic Lymphocytic Leukemia
Introduction: Both hyperkalemia and pseudohyperkalemia occur in the emergency department. True hyperkalemia necessitates emergent treatment while pseudohyperkalemia requires recognition to prevent inappropriate treatment. It is imperative that the emergency physician (EP) have an understanding of the causes and clinical presentations of both phenomena.Case Report: We present a case of an 88-year-old male with chronic lymphocytic leukemia (CLL) and suspected blast crisis who was found to have elevated serum potassium levels without other manifestations of hyperkalemia and eventually was determined to have pseudohyperkalemia due to white cell fragility.Discussion: Differentiation of hyperkalemia and pseudohyperkalemia is a critical skill for the EP. We discuss multiple causes of hyperkalemia and pseudohyperkalemia in an effort to broaden the knowledge base.Conclusion: We present a case of CLL as an unusual cause of pseudohyperkalemia and review common causes of pseudohyperkalemia
Probing the elastic limit of DNA bending
Many structures inside the cell such as nucleosomes and protein-mediated DNA
loops contain sharply bent double-stranded (ds) DNA. Therefore, the energetics
of strong dsDNA bending constitutes an essential part of cellular
thermodynamics. Although the thermomechanical behavior of long dsDNA is well
described by the worm-like chain (WLC) model, the length limit of such elastic
behavior remains controversial. To investigate the energetics of strong dsDNA
bending, we measured the opening rate of small dsDNA loops with contour lengths
of 40-200 bp using Fluorescence Resonance Energy Transfer (FRET). From the
measured relationship of loop stability to loop size, we observed a transition
between two separate bending regimes at a critical loop size below 100 bp.
Above this loop size, the loop lifetime decreased with decreasing loop size in
a manner consistent with an elastic bending stress. Below the critical loop
size, however, the loop lifetime became less sensitive to loop size, indicative
of softening of the double helix. The critical loop size was measured to be ~60
bp with sodium only and ~100 bp with 5 mM magnesium, which suggests that
magnesium facilitates the softening transition. We show that our results are in
quantitative agreement with the kinkable worm-like chain model. Furthermore,
the model parameters constrained by our data can reproduce previously measured
J factors between 50 and 200 bp. Our work provides powerful means to study
dsDNA bending in the strong bending regime
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