5,083 research outputs found
Host seeking parasitic nematodes use specific odors to assess host resources.
Entomopathogenic nematodes (EPNs) are insect parasites used as biological control agents. Free-living infective juveniles (IJs) of EPNs employ host-seeking behaviors to locate suitable hosts for infection. We found that EPNs can differentiate between naïve and infected hosts, and that host attractiveness changes over time in a species-specific manner. We used solid-phase microextraction and gas chromatography/mass spectrometry to identify volatile chemical cues that may relay information about a potential host's infection status and resource availability. Among the chemicals identified from the headspace of infected hosts, 3-Methyl-2-buten-1-ol (prenol) and 3-Hydroxy-2-butanone (AMC) were selected for further behavioral assays due to their temporal correlation with the behavioral changes of IJs towards the infected hosts. Both compounds were repulsive to IJs of Steinernema glaseri and S. riobrave in a dose-dependent manner when applied on an agar substrate. Furthermore, the repulsive effects of prenol were maintained when co-presented with the uninfected host odors, overriding attraction to uninfected hosts. Prenol was attractive to dauers of some free-living nematodes and insect larvae. These data suggest that host-associated chemical cues may have several implications in EPN biology, not only as signals for avoidance and dispersal of conspecifics, but also as attractants for new potential hosts
A Semidefinite Programming Formulation of the LQR Problem and Its Dual
The goal of this paper is to derive a modified formulation of the finite-horizon LQR problem, which can be cast as semidefinite programming problems (SDPs). In addition, based on the the Lagrangian duality, its dual problem is studied. We establish connections between the proposed primal-dual conditions with existing results. As an application of the proposed results, the decentralized LQR analysis and design problems are addressed. Especially, using the structure of the derived LQR formulations, a sufficient but simple and convex surrogate problem is developed for solving decentralized LQR design problems
A Study of the Duality between Kalman Filters and LQR Problems
The goal of this paper is to study a connection between the finite-horizon Kalman filtering and the LQR problems for discrete-time LTI systems. Motivated from the recent duality results on the LQR problem, a Lagrangian dual relation is used to prove that the Kalman filtering problem is a Lagrange dual problem of the LQR problem
New Less Conservative Control Design Conditions for T-S Fuzzy Systems: Relaxed Parameterized Linear Matrix Inequality in the Form of Double Sum
The aim of this study is to investigate less conservative conditions for a
parameterized linear matrix inequality (PLMI) expressed in the form of double
convex sum. This type of PLMI appears frequently in nonlinear T-S fuzzy control
analysis and synthesis problems. In this paper, we derive sufficient linear
matrix inequalities (LMIs) for the PLMI without using any slack variables, by
employing the proposed sum relaxation based on Young's inequality. The derived
LMIs are proven to be less conservative than those presented in [1]. The
proposed technique is applicable to various control design problems for T-S
fuzzy systems represented in PLMIs that take the form of double convex sum.
Furthermore, an example is provided to illustrate the reduced conservatism of
the derived LMIs
Current-Induced Resonant Motion of a Magnetic Vortex Core: Effect of Nonadiabatic Spin Torque
The current-induced resonant excitation of a magnetic vortex core is
investigated by means of analytical and micromagnetic calculations. We find
that the radius and the phase shift of the resonant motion are not correctly
described by the analytical equations because of the dynamic distortion of a
vortex core. In contrast, the initial tilting angle of a vortex core is free
from the distortion and determined by the nonadiabaticity of the spin torque.
It is insensitive to experimentally uncontrollable current-induced in-plane
Oersted field. We propose that a time-resolved imaging of the very initial
trajectory of a core is essential to experimentally estimate the
nonadiabaticity.Comment: 4 pages, 4 figure
I-gel as a first-line airway device in the emergency room for patients with out-of-hospital cardiac arrest
Aim. The optimal method for advanced airway management during cardiac arrest remains controversial. Most patients with out-of-hospital cardiac arrest (OHCA) in Korea are managed with a bag-valve mask by paramedics, while physicians perform advanced airway management in emergency departments (ED). Endotracheal intubation (ETI) has a risk of failure at the first attempt. By contrast, I-gel, a supraglottic airway device, is easier to insert than an endotracheal tube and shows a higher first-attempt success rate than ETI in out-of-hospital settings by paramedics in the United States. We reviewed the use of ETI and I-gel by ED physicians to assess the first attempt success rate in a hospital setting.
Methods. We conducted a retrospective chart review of patients with non-traumatic OHCA who were managed with either ETI using a Macintosh laryngoscope, or I-gel in the ED of Korean hospital from January 2012 to January 2014.
Results. Of 322 adult patients with non-traumatic OHCA, 160 received I-gel and 162 received ETI. The first-attempt success rate was higher in the I-gel group (96.9%) than in the ETI group (84.6%, p < 0.001). The time from arrival to obtaining advanced airway management was shorter in the I-gel group than in the ETI group.
Conclusions. I-gel showed a better first-attempt success rate and shorter insertion time compared with ETI when performed by physicians in a hospital setting
- …