63 research outputs found
Promotion and evacuation on standard Young tableaux of rectangle and staircase shape
(Dual-)promotion and (dual-)evacuation are bijections on SYT(\lambda) for any
partition \lambda. Let c^r denote the rectangular partition (c,...,c) of height
r, and let sc_k (k > 2) denote the staircase partition (k,k-1,...,1). B.
Rhoades showed representation-theoretically that promotion on SYT(c^r) exhibits
the cyclic sieving phenomenon (CSP). In this paper, we demonstrate a promotion-
and evacuation-preserving embedding of SYT(sc_k) into SYT(k^{k+1}). This arose
from an attempt to demonstrate the CSP of promotion action on SYT(sc_k).Comment: 14 pages, typos correcte
Affine Stanley symmetric functions for classical types
We introduce affine Stanley symmetric functions for the special orthogonal
groups, a class of symmetric functions that model the cohomology of the affine
Grassmannian, continuing the work of Lam and Lam, Schilling, and Shimozono on
the special linear and symplectic groups, respectively. For the odd orthogonal
groups, a Hopf-algebra isomorphism is given, identifying (co)homology Schubert
classes with symmetric functions. For the even orthogonal groups, we conjecture
an approximate model of (co)homology via symmetric functions. In the process,
we develop type B and type D non-commutative k-Schur functions as elements of
the nilCoxeter algebra that model homology of the affine Grassmannian.
Additionally, Pieri rules for multiplication by special Schubert classes in
homology are given in both cases. Finally, we present a type-free
interpretation of Pieri factors, used in the definition of noncommutative
k-Schur functions or affine Stanley symmetric functions for any classical type
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Eliciting and annotating uncertainty in spoken language
A major challenge in the ïŹeld of automatic recognition of emotion and affect in speech is the subjective nature of affect labels. The most common approach to acquiring affect labels is to ask a panel of listeners to rate a corpus of spoken utterances along one or more dimensions of interest. For applications ranging from educational technology to voice search to dictation, a speakerâs level of certainty is a primary dimension of interest. In such applications, we would like to know the speakerâs actual level of certainty, but past research has only revealed listenersâ perception of the speakerâs level of certainty. In this paper, we present a method for eliciting spoken utterances using stimuli that we design such that they have a quantitative, crowdsourced legibility score. While we cannot control a speakerâs actual internal level of certainty, the use of these stimuli provides a better estimate of internal certainty compared to existing speech corpora. The Harvard Uncertainty Speech Corpus, containing speech data, certainty annotations, and prosodic features, is made available to the research community.Engineering and Applied Science
Object-Centric Stereo Matching for 3D Object Detection
Safe autonomous driving requires reliable 3D object detection-determining the
6 DoF pose and dimensions of objects of interest. Using stereo cameras to solve
this task is a cost-effective alternative to the widely used LiDAR sensor. The
current state-of-the-art for stereo 3D object detection takes the existing
PSMNet stereo matching network, with no modifications, and converts the
estimated disparities into a 3D point cloud, and feeds this point cloud into a
LiDAR-based 3D object detector. The issue with existing stereo matching
networks is that they are designed for disparity estimation, not 3D object
detection; the shape and accuracy of object point clouds are not the focus.
Stereo matching networks commonly suffer from inaccurate depth estimates at
object boundaries, which we define as streaking, because background and
foreground points are jointly estimated. Existing networks also penalize
disparity instead of the estimated position of object point clouds in their
loss functions. We propose a novel 2D box association and object-centric stereo
matching method that only estimates the disparities of the objects of interest
to address these two issues. Our method achieves state-of-the-art results on
the KITTI 3D and BEV benchmarks.Comment: Accepted in ICRA 202
Shark predation on migrating adult american eels (Anguilla rostrata) in the Gulf of St. Lawrence.
In an attempt to document the migratory pathways and the environmental conditions encountered by American eels during their oceanic migration to the Sargasso Sea, we tagged eight silver eels with miniature satellite pop-up tags during their migration from the St. Lawrence River in Québec, Canada. Surprisingly, of the seven tags that successfully transmitted archived data, six were ingested by warm-gutted predators, as observed by a sudden increase in water temperature. Gut temperatures were in the range of 20 to 25°C-too cold for marine mammals but within the range of endothermic fish. In order to identify the eel predators, we compared their vertical migratory behavior with those of satellite-tagged porbeagle shark and bluefin tuna, the only endothermic fishes occurring non-marginally in the Gulf of St. Lawrence. We accurately distinguished between tuna and shark by using the behavioral criteria generated by comparing the diving behavior of these two species with those of our unknown predators. Depth profile characteristics of most eel predators more closely resembled those of sharks than those of tuna. During the first days following tagging, all eels remained in surface waters and did not exhibit diel vertical migrations. Three eels were eaten at this time. Two eels exhibited inverse diel vertical migrations (at surface during the day) during several days prior to predation. Four eels were eaten during daytime, whereas the two night-predation events occurred at full moon. Although tagging itself may contribute to increasing the eel's susceptibility to predation, we discuss evidence suggesting that predation of silver-stage American eels by porbeagle sharks may represent a significant source of mortality inside the Gulf of St. Lawrence and raises the possibility that eels may represent a reliable, predictable food resource for porbeagle sharks
Preassembled GPCR signaling complexes mediate distinct cellular responses to ultralow ligand concentrations
G proteinâcoupled receptors (GPCRs) are the largest class of cell surface signaling proteins, participate in nearly all physiological processes, and are the targets of 30% of marketed drugs. Typically, nanomolar to micromolar concentrations of ligand are used to activate GPCRs in experimental systems. We detected GPCR responses to a wide range of ligand concentrations, from attomolar to millimolar, by measuring GPCR-stimulated production of cyclic adenosine monophosphate (cAMP) with high spatial and temporal resolution. Mathematical modeling showed that femtomolar concentrations of ligand activated, on average, 40% of the cells in a population provided that a cell was activated by one to two binding events. Furthermore, activation of the endogenous ÎČ2-adrenergic receptor (ÎČ2AR) and muscarinic acetylcholine M3 receptor (M3R) by femtomolar concentrations of ligand in cell lines and human cardiac fibroblasts caused sustained increases in nuclear translocation of extracellular signalâregulated kinase (ERK) and cytosolic protein kinase C (PKC) activity, respectively. These responses were spatially and temporally distinct from those that occurred in response to higher concentrations of ligand and resulted in a distinct cellular proteomic profile. This highly sensitive signaling depended on the GPCRs forming preassembled, higher-order signaling complexes at the plasma membrane. Recognizing that GPCRs respond to ultralow concentrations of neurotransmitters and hormones challenges established paradigms of drug action and provides a previously unappreciated aspect of GPCR activation that is quite distinct from that typically observed with higher ligand concentrations
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