2,544 research outputs found
Cell-Type-Specific Recruitment of Amygdala Interneurons to Hippocampal Theta Rhythm and Noxious Stimuli In Vivo
Neuronal synchrony in the basolateral amygdala (BLA) is critical for emotional behavior. Coordinated theta-frequency oscillations between the BLA and the hippocampus and precisely timed integration of salient sensory stimuli in the BLA are involved in fear conditioning. We characterized GABAergic interneuron types of the BLA and determined their contribution to shaping these network activities. Using in vivo recordings in rats combined with the anatomical identification of neurons, we found that the firing of BLA interneurons associated with network activities was cell type specific. The firing of calbindin-positive interneurons targeting dendrites was precisely theta-modulated, but other cell types were heterogeneously modulated, including parvalbumin-positive basket cells. Salient sensory stimuli selectively triggered axo-axonic cells firing and inhibited firing of a disctinct projecting interneuron type. Thus, GABA is released onto BLA principal neurons in a time-, domain-, and sensory-specific manner. These specific synaptic actions likely cooperate to promote amygdalo-hippocampal synchrony involved in emotional memory formation
Snowmass 2001: Jet Energy Flow Project
Conventional cone jet algorithms arose from heuristic considerations of LO
hard scattering coupled to independent showering. These algorithms implicitly
assume that the final states of individual events can be mapped onto a unique
set of jets that are in turn associated with a unique set of underlying hard
scattering partons. Thus each final state hadron is assigned to a unique
underlying parton. The Jet Energy Flow (JEF) analysis described here does not
make such assumptions. The final states of individual events are instead
described in terms of flow distributions of hadronic energy. Quantities of
physical interest are constructed from the energy flow distribution summed over
all events. The resulting analysis is less sensitive to higher order
perturbative corrections and the impact of showering and hadronization than the
standard cone algorithms.Comment: REVTeX4, 13 pages, 6 figures; Contribution to the P5 Working Group on
QCD and Strong Interactions at Snowmass 200
SOME ABSTRACT PROPERTIES OF SEMIGROUPS APPEARING IN SUPERCONFORMAL THEORIES
A new type of semigroups which appears while dealing with
superconformal symmetry in superstring theories is considered. The ideal series
having unusual abstract properties is constructed. Various idealisers are
introduced and studied. The ideal quasicharacter is defined. Green's relations
are found and their connection with the ideal quasicharacter is established.Comment: 11 page
Optical and near-infrared observations of SN 2011dh - The first 100 days
We present optical and near-infrared (NIR) photometry and spectroscopy of the
Type IIb supernova (SN) 2011dh for the first 100 days. We complement our
extensive dataset with SWIFT ultra-violet (UV) and Spitzer mid-infrared (MIR)
data to build a UV to MIR bolometric lightcurve using both photometric and
spectroscopic data. Hydrodynamical modelling of the SN based on this bolometric
lightcurve have been presented in Bersten (2012). We find that the absorption
minimum for the hydrogen lines is never seen below ~11000 km/s but approaches
this value as the lines get weaker. This suggests that the interface between
the helium core and hydrogen rich envelope is located near this velocity in
agreement with the Bersten et al. (2012) He4R270 ejecta model. Spectral
modelling of the hydrogen lines using this ejecta model supports the conclusion
and we find a hydrogen mass of 0.01-0.04 solar masses to be consistent with the
observed spectral evolution. We estimate that the photosphere reaches the
helium core at 5-7 days whereas the helium lines appear between ~10 and ~15
days, close to the photosphere and then move outward in velocity until ~40
days. This suggests that increasing non-thermal excitation due to decreasing
optical depth for the gamma-rays is driving the early evolution of these lines.
We also provide and discuss pre- and post-explosion observations of the SN site
which shows a reduction by 75 percent in flux at the position of the yellow
supergiant coincident with SN 2011dh. The B, V and r band decline rates of
0.0073, 0.0090 and 0.0053 mag/day respectively are consistent with the
remaining flux being emitted by the SN. Hence we find that the star was indeed
the progenitor of SN 2011dh as previously suggested by Maund et al. (2011) and
which is also consistent with the results from the hydrodynamical modelling.Comment: 38 pages, 27 figures, 18 tables, accepted for publication by A&
Massive stars exploding in a He-rich circumstellar medium. IV. Transitional Type Ibn Supernovae
We present ultraviolet, optical and near-infrared data of the Type Ibn
supernovae (SNe) 2010al and 2011hw. SN 2010al reaches an absolute magnitude at
peak of M(R) = -18.86 +- 0.21. Its early light curve shows similarities with
normal SNe Ib, with a rise to maximum slower than most SNe Ibn. The spectra are
dominated by a blue continuum at early stages, with narrow P-Cygni He I lines
indicating the presence of a slow-moving, He-rich circumstellar medium. At
later epochs the spectra well match those of the prototypical SN Ibn 2006jc,
although the broader lines suggest that a significant amount of He was still
present in the stellar envelope at the time of the explosion. SN 2011hw is
somewhat different. It was discovered after the first maximum, but the light
curve shows a double-peak. The absolute magnitude at discovery is similar to
that of the second peak (M(R) = -18.59 +- 0.25), and slightly fainter than the
average of SNe Ibn. Though the spectra of SN 2011hw are similar to those of SN
2006jc, coronal lines and narrow Balmer lines are cleary detected. This
indicates substantial interaction of the SN ejecta with He-rich, but not
H-free, circumstellar material. The spectra of SN 2011hw suggest that it is a
transitional SN Ibn/IIn event similar to SN 2005la. While for SN 2010al the
spectro-photometric evolution favours a H-deprived Wolf-Rayet progenitor (of
WN-type), we agree with the conclusion of Smith et al. (2012) that the
precursor of SN 2011hw was likely in transition from a luminous blue variable
to an early Wolf-Rayet (Ofpe/WN9) stage.Comment: 23 pages, 11 figures, 6 tables. Accepted by MNRA
Predicate Abstraction for Linked Data Structures
We present Alias Refinement Types (ART), a new approach to the verification
of correctness properties of linked data structures. While there are many
techniques for checking that a heap-manipulating program adheres to its
specification, they often require that the programmer annotate the behavior of
each procedure, for example, in the form of loop invariants and pre- and
post-conditions. Predicate abstraction would be an attractive abstract domain
for performing invariant inference, existing techniques are not able to reason
about the heap with enough precision to verify functional properties of data
structure manipulating programs. In this paper, we propose a technique that
lifts predicate abstraction to the heap by factoring the analysis of data
structures into two orthogonal components: (1) Alias Types, which reason about
the physical shape of heap structures, and (2) Refinement Types, which use
simple predicates from an SMT decidable theory to capture the logical or
semantic properties of the structures. We prove ART sound by translating types
into separation logic assertions, thus translating typing derivations in ART
into separation logic proofs. We evaluate ART by implementing a tool that
performs type inference for an imperative language, and empirically show, using
a suite of data-structure benchmarks, that ART requires only 21% of the
annotations needed by other state-of-the-art verification techniques
An Equilibrium Model of Managerial Compensation
This paper studies a general equilibrium model with two groups of agents, investors (shareholders) and managers of firms, in which managerial effort is not observable and influences the probabilities of firms' outcomes. Shareholders of each firm offer the manager an incentive contract which maximizes the firm's market value, under the assumption that the financial markets are complete relative to the possible outcomes of the firms. The paper studies two sources of inefficiency of equilibrium. First, when investors are risk averse and effort influences probability, market-value maximization differs from maximization of expected utility. Second, because the optimal contract exploits all sources of information for inferring managerial effort, when firms' outputs are correlated the contract of a manager depends on the outcomes of other firms. This leads to an external effect of the effort of one manager on the compensation of other managers, which market-value maximization ignores. We show that under typical conditions these two effects lead to an under-provision of effort in equilibrium. These inefficiencies disappear however if each firm is replicated, and in the limit there is a continuum of firms of each type
Automatically refining partial specifications for Program Verification
10.1007/978-3-642-21437-0_28Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)6664 LNCS369-38
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Highly efficient separation of actinides from lanthanides by a phenanthroline-derived bis-triazine ligand
The synthesis, lanthanide complexation, and solvent ex- traction of actinide(III) and lanthanide(III) radiotracers from nitric acid solutions by a phenanthroline-derived quadridentate bis-triazine ligand are described. The ligand separates Am(III) and Cm(III) from the lanthanides with remarkably high efficiency, high selectivity, and fast extraction kinetics compared to its 2,2'-bipyridine counterpart. Structures of the 1:2 bis-complexes of the ligand with Eu(III) and Yb(III) were elucidated by X-ray crystallography and force field calculations, respec-tively. The Eu(III) bis-complex is the first 1:2 bis-complex of a quadridentate bis-triazine ligand to be characterized by crystallography. The faster rates of extraction were verified by kinetics measurements using the rotating membrane cell technique in several diluents. The improved kinetics of metal ion extraction are related to the higher surface activity of the ligand at the phase interface. The improvement in the ligand's properties on replacing the bipyridine unit with a phenanthroline unit far exceeds what was anticipated based on ligand design alone
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