299 research outputs found
zonoLAB: A MATLAB toolbox for set-based control systems analysis using hybrid zonotopes
This paper introduces zonoLAB, a MATLAB-based toolbox for set-based control
system analysis using the hybrid zonotope set representation. Hybrid zonotopes
have proven to be an expressive set representation that can exactly represent
the reachable sets of mixed-logical dynamical systems and tightly approximate
the reachable sets of nonlinear dynamic systems. Moreover, hybrid zonotopes can
exactly represent the continuous piecewise linear control laws associated with
model predictive control and the input-output mappings of neural networks with
piecewise linear activation functions. The hybrid zonotope set representation
is also highly exploitable, where efficient methods developed for mixed-integer
linear programming can be directly used for set operation and analysis. The
zonoLAB toolbox is designed to make these capabilities accessible to the
dynamic systems and controls community, with functionality spanning fundamental
operations with hybrid zonotope, constrained zonotope, and zonotope set
representations, powerful set analysis tools, and general-purpose algorithms
for reachability analysis of open- and closed-loop systems
Advances in the surgical management of bone tumors
Chirurgia guzów kości stanowi duże wyzwanie, szczególnie gdy nowotwory są zlokalizowane w wąsko ograniczonych obszarach anatomicznych i przylegają do ważnych narządów i pęczków nerwowo-naczyniowych. Resekcja wymaga dużej dokładności w celu zapewnienia bezpieczeństwa, uzyskania ujemnych marginesów chirurgicznych i oszczędzenia, jeśli to możliwe, ważnych narządów. Celem opracowania był przegląd publikacji dotyczących postępu w leczeniu chirurgicznym guzów kości, które ukazały się w ciągu ubiegłego roku. Większość zebranych artykułów koncentrowała się na wykorzystaniu w leczeniu chirurgicznym sprzętu komputerowego. Pojawia się coraz więcej dowodów na istotną rolę trójwymiarowej nawigacji podczas resekcji guzów kości. Opracowywane są coraz nowsze materiały służące do rekonstrukcji tkanek, które wspomagają szybkie gojenie i zapobiegają powikłaniom infekcyjnym. Optymalne postępowanie powinno obejmować stworzenie dobrze opracowanego planu przedoperacyjnego opartego na wielospecjalistycznym podejściu pod nadzorem onkologa ortopedy.Bone tumor surgery is extremely challenging, particularly when tumors are located in tightly confined anatomical areas and abutting critical organs and neurovascular structures. Tumor resection requires good cutting accuracy to ensure safety, to achieve negative margins, and to preserve critical structures when possible. The purpose of this paper was to review the literature on the surgical advances for bone tumor surgery published within the last year. The majority of literature identified focused on computer-assisted surgical approaches. There is increasing evidence that 3D navigation plays an important role in the resection of bone tumors. Reconstruction materials that encourage healing and prevent infections are also in development. Optimal care includes execution of a well-developed pre-operative plan using a multidisciplinary approach led by the orthopaedic oncologist
Increased population size of fish in a lowland river following restoration of structural habitat
Monomeric PcrA helicase processively unwinds plasmid lengths of DNA in the presence of the initiator protein RepD
The helicase PcrA unwinds DNA during asymmetric replication of plasmids, acting with an initiator protein, in our case RepD. Detailed kinetics of PcrA activity were measured using bulk solution and a single-molecule imaging technique to investigate the oligomeric state of the active helicase complex, its processivity and the mechanism of unwinding. By tethering either DNA or PcrA to a microscope coverslip surface, unwinding of both linear and natural circular plasmid DNA by PcrA/RepD was followed in real-time using total internal reflection fluorescence microscopy. Visualization was achieved using a fluorescent single-stranded DNA-binding protein. The single-molecule data show that PcrA, in combination with RepD, can unwind plasmid lengths of DNA in a single run, and that PcrA is active as a monomer. Although the average rate of unwinding was similar in single-molecule and bulk solution assays, the single-molecule experiments revealed a wide distribution of unwinding speeds by different molecules. The average rate of unwinding was several-fold slower than the PcrA translocation rate on single-stranded DNA, suggesting that DNA unwinding may proceed via a partially passive mechanism. However, the fastest dsDNA unwinding rates measured in the single-molecule unwinding assays approached the PcrA translocation speed measured on ssDNA
Divergent evolution of arrested development in the dauer stage of Caenorhabditis elegans and the infective stage of Heterodera glycines
The generation and analysis of over 20,000 ESTs allowed the identification and expression profiling of 6,860 predicted genes in the nematode Heterodera glycines. This revealed that gene expression patterns in the dauer stage of Caenorhabditis elegans are not conserved in H. glycines
Modular Robotic Vehicle
A modular robotic vehicle includes a chassis, driver input devices, an energy storage system (ESS), a power electronics module (PEM), modular electronic assemblies (eModules) connected to the ESS via the PEM, one or more master controllers, and various embedded controllers. Each eModule includes a drive wheel containing a propulsion-braking module, and a housing containing propulsion and braking control assemblies with respective embedded propulsion and brake controllers, and a mounting bracket covering a steering control assembly with embedded steering controllers. The master controller, which is in communication with each eModule and with the driver input devices, communicates with and independently controls each eModule, by-wire, via the embedded controllers to establish a desired operating mode. Modes may include a two-wheel, four-wheel, diamond, and omni-directional steering modes as well as a park mode. A bumper may enable docking with another vehicle, with shared control over the eModules of the vehicles
CMBPol Mission Concept Study: Probing Inflation with CMB Polarization
We summarize the utility of precise cosmic microwave background (CMB)
polarization measurements as probes of the physics of inflation. We focus on
the prospects for using CMB measurements to differentiate various inflationary
mechanisms. In particular, a detection of primordial B-mode polarization would
demonstrate that inflation occurred at a very high energy scale, and that the
inflaton traversed a super-Planckian distance in field space. We explain how
such a detection or constraint would illuminate aspects of physics at the
Planck scale. Moreover, CMB measurements can constrain the scale-dependence and
non-Gaussianity of the primordial fluctuations and limit the possibility of a
significant isocurvature contribution. Each such limit provides crucial
information on the underlying inflationary dynamics. Finally, we quantify these
considerations by presenting forecasts for the sensitivities of a future
satellite experiment to the inflationary parameters.Comment: 107 pages, 14 figures, 17 tables; Inflation Working Group
contribution to the CMBPol Mission Concept Study; v2: typos fixed and
references adde
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