4,685 research outputs found
USE OF INHALANT ANESTHETICS IN THREE SNAKE SPECIES
Different snake species respond differently to various anesthetic agents. Hence, an anesthetic procedure developed for one species cannot necessarily be safely transferred to another species. The goal of this paper is to summarize our experience using inhalant anesthetics on three snake species, including both procedures that were successful and those we found to be less satisfactory. We found isoflurane delivered with a precision vaporizer to be the best agent to anesthetize black rat snakes (Elaphe o. obsoleta). Sex and mass did not seem to affect induction times in black rat snakes, but larger female rat snakes recovered faster from anesthesia than smaller females. Halothane delivered in the open method provided consistent anesthesia in northern water snakes (Nerodia s. sipedon), although it caused some mortality and should not be used on debilitated patients. Halothane delivered with a precision vaporizer may be used to anesthetize eastern massasauga rattlesnakes (Sistrurus c. catenatus). However, care must be taken to prevent mortality resulting from anesthetic overdose. Sex and mass had no effect on induction and recovery times in the rattlesnakes, but stressed animals require longer induction and recovery times
Stimuli-Responsive Polyguanidino-Oxanorbornene Membrane Transporters as Multicomponent Sensors in Complex Matrices
We introduce guanidinium-containing synthetic polymers based on polyguanidino-oxanorbornenes (PGONs) as anion transporters in lipid bilayers that can be activated and inactivated by chemical stimulation. According to fluorogenic anion export experiments with vesicles, PGON transporters are most active in neutral bilayers near their phase transition, with EC50's in the nanomolar range. Six times higher effective transporter concentrations were measured with aminonaphthalene-1,3,6-trisulfonate than with 5(6)-carboxyfluorescein, demonstrating the importance of anion binding for transport and excluding nonspecific efflux. Negative surface potentials efficiently annihilate transport activity, while inside-negative membrane potentials slightly increase it. These trends demonstrate the functional importance of counterions to hinder the binding of hydrophilic counterions and to minimize the global positive charge of the transporter-counterion complexes. Strong, nonlinear increases in activity with polymer length reveal a significant polymer effect. Overall, the characteristics of PGONs do not match those of similar systems (for example, polyarginine) and hint toward an interesting mode of action, clearly different from nonspecific leakage caused by detergents. The activity of PGONs increases in the presence of amphiphilic anions such as pyrenebutyrate (EC50 = 70 microM), while several other amphiphilic anions tested were inactive. PGONs are efficiently inactivated by numerous hydrophilic anions including ATP (IC 50 = 150 microM), ADP (IC50 = 460 microM), heparin (IC50 = 1.0 microM), phytate (IC50 = 0.4 microM), and CB hydrazide (IC50 = 26 microM). The compatibility of this broad responsiveness with multicomponent sensing in complex matrices is discussed and illustrated with lactate sensing in sour milk. The PGON lactate sensor operates together with lactate oxidase as a specific signal generator and CB hydrazide as an amplifier for covalent capture of the pyruvate product as CB hydrazone (IC50 = 1.5 microM)
Stationary time correlations for fermions after a quench in the presence of an impurity
We consider the quench dynamics of non-interacting fermions in one dimension
in the presence of a finite-size impurity at the origin. This impurity is
characterized by general momentum-dependent reflection and transmission
coefficients which are changed from to at time . The initial state is at equilibrium with
such that the system is cut in two independent halves with
, respectively to the right and to the left of
the impurity. We obtain the exact large time limit of the multi-time
correlations. These correlations become time translationally invariant, and are
non-zero in two different regimes: (i) for where the system reaches a
non-equilibrium steady state (NESS) (ii) for , i.e., the ray-regime.
For a repulsive impurity these correlations are independent of , , while in the presence of bound states they
oscillate and memory effects persist. We show that these nontrivial
relaxational properties can be retrieved in a simple manner from the large time
behaviour of the single particle wave functions.Comment: Main text: 7 pages, 3 figures. Supp. Mat.: 31 pages, 4 figure
Multiscale Parallel Tempering for Fast Sampling on Redistricting Plans
When auditing a redistricting plan, a persuasive method is to compare the
plan with an ensemble of neutrally drawn redistricting plans. Ensembles are
generated via algorithms that sample distributions on balanced graph
partitions. To audit the partisan difference between the ensemble and a given
plan, one must ensure that the non-partisan criteria are matched so that we may
conclude that partisan differences come from bias rather than, for example,
levels of compactness or differences in community preservation. Certain
sampling algorithms allow one to explicitly state the policy-based probability
distribution on plans, however, these algorithms have shown poor mixing times
for large graphs (i.e. redistricting spaces) for all but a few specialized
measures. In this work, we generate a multiscale parallel tempering approach
that makes local moves at each scale. The local moves allow us to adopt a wide
variety of policy-based measures. We examine our method in the state of
Connecticut and succeed at achieving fast mixing on a policy-based distribution
that has never before been sampled at this scale. Our algorithm shows promise
to expand to a significantly wider class of measures that will (i) allow for
more principled and situation-based comparisons and (ii) probe for the typical
partisan impact that policy can have on redistricting.Comment: 26 pages with appendix; 11 figure
FIREWORKS U38-to-24 micron photometry of the GOODS-CDFS: multi-wavelength catalog and total IR properties of distant Ks-selected galaxies
We present a Ks-selected catalog, dubbed FIREWORKS, for the Chandra Deep
Field South (CDFS) containing photometry in U_38, B_435, B, V, V_606, R, i_775,
I, z_850, J, H, Ks, [3.6 um], [4.5 um], [5.8 um], [8.0 um], and the MIPS [24
um] band. The imaging has a typical Ks limit of 24.3 mag (5 sigma, AB) and
coverage over 113 arcmin^2 in all bands and 138 arcmin^2 in all bands but H. We
cross-correlate our catalog with the 1 Ms X-ray catalog by Giacconi et al.
(2002) and with all available spectroscopic redshifts to date. We find and
explain systematic differences in a comparison with the 'z_850 + Ks'-selected
GOODS-MUSIC catalog that covers ~90% of the field. We exploit the U38-to-24
micron photometry to determine which Ks-selected galaxies at 1.5<z<2.5 have the
brightest total IR luminosities and which galaxies contribute most to the
integrated total IR emission. The answer to both questions is that red galaxies
are dominating in the IR. This is true no matter whether color is defined in
the rest-frame UV, optical, or optical-to-NIR. We do find however that among
the reddest galaxies in the rest-frame optical, there is a population of
sources with only little mid-IR emission, suggesting a quiescent nature.Comment: Accepted for publication in the Astrophysical Journal, 20 pages, 10
figures, reference to website correcte
Resolution limits of quantum ghost imaging
Quantum ghost imaging uses photon pairs produced from parametric downconversion to enable an alternative method of image acquisition. Information from either one of the photons does not yield an image, but an image can be obtained by harnessing the correlations between them. Here we present an examination of the resolution limits of such ghost imaging systems. In both conventional imaging and quantum ghost imaging the resolution of the image is limited by the point-spread function of the optics associated with the spatially resolving detector. However, whereas in conventional imaging systems the resolution is limited only by this point spread function, in ghost imaging we show that the resolution can be further degraded by reducing the strength of the spatial correlations inherent in the downconversion process
Accelerating black holes in 2 + 1 dimensions: holography revisited
This paper studies the holographic description of 2 + 1-dimensional accelerating black holes. We start by using an ADM decomposition of the coordinates suitable to identify boundary data. As a consequence, the holographic CFT lies in a fixed curved background which is described by the holographic stress tensor of a perfect fluid. We compute the Euclidean action ensuring that the variational principle is satisfied in the presence of the domain wall. This requires including the Gibbons-Hawking-York term associated with internal boundaries on top of the standard renormalised AdS3 action. Finally, we compute the entanglement entropy by firstly mapping the solution to the Rindler-AdS spacetime in which the Ryu-Takayanagi surface is easily identifiable. We found that as the acceleration increases the accessible region of the conformal boundary decreases and also the entanglement entropy, indicating a loss of information in the dual theory due to acceleration
Measuring What We Intend: A Validation Argument for the Grade 5 Problem-Solving Measure (PSM5)
The purpose of this proceeding is to share validity evidence for the Problem-solving Measure for grade 5 (PSM5). The PSM5 is one test in the PSM series, which is designed for grades 3-8. PSMs are intended to measure students\u27 problem-solving performance related to the Common Core State Standards for Mathematics (i.e., content and practices). In addition to sharing validity evidence connected to the PSM5, we discuss implications for its use in current research and practice
Accelerating Black Holes in dimensions: Holography revisited
This paper studies the holographic description of dimensional
accelerating black holes. We start by using an ADM decomposition of the
coordinates suitable to identify boundary data. As a consequence, the
holographic CFT lies in a fixed curved background which is described by the
holographic stress tensor of a perfect fluid. We compute the Euclidean action
ensuring that the variational principle is satisfied in the presence of the
domain wall. This requires including the Gibbons--Hawking--York term associated
with internal boundaries on top of the standard renormalised AdS action.
Finally, we compute the entanglement entropy by firstly mapping the solution to
the Rindler--AdS spacetime in which the Ryu--Takayanagi surface is easily
identifiable. We found that as the acceleration increases the accessible region
of the conformal boundary decreases and also the entanglement entropy,
indicating a loss of information in the dual theory due to acceleration.Comment: 15 pages, 7 figures, 1 table. V2: minor changes, references added,
typos corrected, accepted for publication in JHE
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