4,230 research outputs found
We Are Infinite: Confronting High School Simulacra in Stephen Chboskyâs \u3cem\u3eThe Perks of Being a Wallflower\u3c/em\u3e
âStephen Chbosky saved lives. No, not in the saving-a-cat-from-a-burning-building way nor performing the Heimlich on a little old lady at a restaurant. He saved lives by writing a peculiar little green bookâ (Aquino). The Perks of Being a Wallflower has become a phenomenon among adolescents in contemporary America. Passed on through recommendations for over 15 years, Charlieâs story has administered a sense of hope to the young people who read his letters. They say they relate to Charlie, that he makes them feel understood. For some, his story has saved their lives; at least two people have written to Chbosky to tell him that they gave up attempting suicide after they read his novel (Beckman). Several journalists have questioned Chbosky about his perspective on the bookâs impact on his readers. He has replied with amazement, ââItâs everything at onceâŠ.Itâs bizarre that a book would be that final barrier between life and deathââ (qtd. in Beckman)
Development and Use of an Environmental DNA Tool to Monitor Recovery of the Critically Endangered Smalltooth Sawfish, Pristis pectinata, in the Northwest Atlantic
The Critically Endangered Smalltooth Sawfish, Pristis pectinata, was once common in the tropical and subtropical waters of the Atlantic Ocean; however, following global declines in range and abundance over the past century, individuals were restricted to the waters of south and southwest Florida (SWFL) by about the 1980âs. Recently, public encounter reports have emerged in historically occupied habitats in United States waters, suggesting individuals are present in, or re-occupying, these areas, although the status of P. pectinata outside of SWFL is not currently well understood. Targeted environmental DNA (eDNA) surveys were chosen to assess the occurrence of P. pectinata in these formerly inhabited waters due to the rapid, cost-effective, and non-invasive advantages of this technique over traditional survey methods for P. pectinata like gill nets. This research developed and validated a species-specific eDNA assay capable of targeting P. pectinata DNA in water samples at concentrations as low as 0.08 copies/ÎŒL using Droplet Digitalâą PCR. This assay was then used in three formerly occupied estuaries in the western Atlantic that had recent, verified encounter reports: Tampa Bay and the Indian River Lagoon (IRL), Florida, and the Mississippi Sound, Mississippi. Pristis pectinata DNA was detected in water samples collected from the IRL in 2018 and 2019, and the Mississippi Sound in 2018, indicating at least one individual was present in the vicinity near the time of sample collection. These results provide another line of evidence for potential re-occupation; however, long-term, comprehensive eDNA surveys are needed to help foster future recovery
Data-efficient Neuroevolution with Kernel-Based Surrogate Models
Surrogate-assistance approaches have long been used in computationally
expensive domains to improve the data-efficiency of optimization algorithms.
Neuroevolution, however, has so far resisted the application of these
techniques because it requires the surrogate model to make fitness predictions
based on variable topologies, instead of a vector of parameters. Our main
insight is that we can sidestep this problem by using kernel-based surrogate
models, which require only the definition of a distance measure between
individuals. Our second insight is that the well-established Neuroevolution of
Augmenting Topologies (NEAT) algorithm provides a computationally efficient
distance measure between dissimilar networks in the form of "compatibility
distance", initially designed to maintain topological diversity. Combining
these two ideas, we introduce a surrogate-assisted neuroevolution algorithm
that combines NEAT and a surrogate model built using a compatibility distance
kernel. We demonstrate the data-efficiency of this new algorithm on the low
dimensional cart-pole swing-up problem, as well as the higher dimensional
half-cheetah running task. In both tasks the surrogate-assisted variant
achieves the same or better results with several times fewer function
evaluations as the original NEAT.Comment: In GECCO 201
Edge theories in Projected Entangled Pair State models
We study the edge physics of gapped quantum systems in the framework of
Projected Entangled Pair State (PEPS) models. We show that the effective
low-energy model for any region acts on the entanglement degrees of freedom at
the boundary, corresponding to physical excitations located at the edge. This
allows us to determine the edge Hamiltonian in the vicinity of PEPS models, and
we demonstrate that by choosing the appropriate bulk perturbation, the edge
Hamiltonian can exhibit a rich phase diagram and phase transitions. While for
models in the trivial phase any Hamiltonian can be realized at the edge, we
show that for topological models, the edge Hamiltonian is constrained by the
topological order in the bulk which can e.g. protect a ferromagnetic Ising
chain at the edge against spontaneous symmetry breaking.Comment: 5 pages, 4 figure
Activation of Gastrinâreleasing Peptide Receptors in the Lumbosacral Spinal Cord is Required for Ejaculation in Male Rats
Introduction.â Ejaculation is a complex reflex mediated by a spinal ejaculation generator located in the lumbosacral spinal cord and consisting of a population of lumbar spinothalamic (LSt) neurons. LSt neurons and their intraspinal axonal projections contain several neuropeptides, including gastrinâreleasing peptide (GRP). Aim.â To test the hypothesis that GRP is critically involved in mediating ejaculation by acting in autonomic and motor areas of the lumbosacral spinal cord, utilizing a physiological paradigm to investigate ejaculatory reflexes in isolation of supraspinal inputs. Methods.â Dual immunohistochemistry for GRP and galanin was performed to investigate coâexpression of GRP in LSt cells of control male rats. Next, anesthetized, spinalized male rats received intrathecal infusions of either GRP antagonist RCâ3095 (0, 10, or 20ânmol/10â”L) or GRP (0, 0.2, 0.5ânmol/10â”L). Ejaculatory reflexes were induced by electrical stimulation of the dorsal penile nerve (DPN) which reliably triggers rhythmic increases in seminal vesicle pressure (SVP) and contractions of the bulbocavernosus muscle (BCM), indicative of the emission and expulsion phases of ejaculation, respectively. Main Outcome Measures.â GRP in LSt cells was expressed as percentages of coâexpression. SVP and electromyographic recording (EMG) of BCM activity following drug treatment and DPN stimulation were recorded and analyzed for numbers of SVP increases, BCM events and bursts. Results.â GRP was exclusively expressed in LSt cells and axons. Intrathecal infusion of RCâ3095, but not saline, blocked SVP increases and BCM bursting induced by DPN stimulation. Intrathecal infusions of GRP, but not saline, triggered SVP increases and BCM bursting in 43â66% of animals and facilitated SVP increases and BCM bursting induced by subthreshold DPN stimulation in all animals. Conclusion.â These data support a critical role for GRP for control of the emission and expulsion phases of ejaculation in male rats by acting in LSt target areas in the lumbosacral spinal cord. Kozyrev N, Lehman MN, and Coolen LM. Activation of gastrinâreleasing peptide receptors in the lumbosacral spinal cord is required for ejaculation in male rats. J Sex Med 2012;9:1303â1318.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91163/1/j.1743-6109.2012.02688.x.pd
Covariance Matrix Adaptation for the Rapid Illumination of Behavior Space
We focus on the challenge of finding a diverse collection of quality
solutions on complex continuous domains. While quality diver-sity (QD)
algorithms like Novelty Search with Local Competition (NSLC) and MAP-Elites are
designed to generate a diverse range of solutions, these algorithms require a
large number of evaluations for exploration of continuous spaces. Meanwhile,
variants of the Covariance Matrix Adaptation Evolution Strategy (CMA-ES) are
among the best-performing derivative-free optimizers in single-objective
continuous domains. This paper proposes a new QD algorithm called Covariance
Matrix Adaptation MAP-Elites (CMA-ME). Our new algorithm combines the
self-adaptation techniques of CMA-ES with archiving and mapping techniques for
maintaining diversity in QD. Results from experiments based on standard
continuous optimization benchmarks show that CMA-ME finds better-quality
solutions than MAP-Elites; similarly, results on the strategic game Hearthstone
show that CMA-ME finds both a higher overall quality and broader diversity of
strategies than both CMA-ES and MAP-Elites. Overall, CMA-ME more than doubles
the performance of MAP-Elites using standard QD performance metrics. These
results suggest that QD algorithms augmented by operators from state-of-the-art
optimization algorithms can yield high-performing methods for simultaneously
exploring and optimizing continuous search spaces, with significant
applications to design, testing, and reinforcement learning among other
domains.Comment: Accepted to GECCO 202
Learning the Designer's Preferences to Drive Evolution
This paper presents the Designer Preference Model, a data-driven solution
that pursues to learn from user generated data in a Quality-Diversity
Mixed-Initiative Co-Creativity (QD MI-CC) tool, with the aims of modelling the
user's design style to better assess the tool's procedurally generated content
with respect to that user's preferences. Through this approach, we aim for
increasing the user's agency over the generated content in a way that neither
stalls the user-tool reciprocal stimuli loop nor fatigues the user with
periodical suggestion handpicking. We describe the details of this novel
solution, as well as its implementation in the MI-CC tool the Evolutionary
Dungeon Designer. We present and discuss our findings out of the initial tests
carried out, spotting the open challenges for this combined line of research
that integrates MI-CC with Procedural Content Generation through Machine
Learning.Comment: 16 pages, Accepted and to appear in proceedings of the 23rd European
Conference on the Applications of Evolutionary and bio-inspired Computation,
EvoApplications 202
Neurons of origin and fiber trajectory of amygdalofugal projections to the medial preoptic area in syrian hamsters
The amygdaloid neurons of origin and the trajectory of amygdaloid fibers to the medial preoptic area of the adult male Syrian hamster were identified by using horseradish peroxidase (HRP) histochemistry. After iontophoresis of HRP into the medial preoptic area, retrogradely labeled amygdaloid neurons were located in the dorsal and caudal parts of the medial amygdaloid nucleus and throughout the amygdalohippocampal area. No amygdaloid neurons were labeled after HRP applications confined to the most rostral portion of the medial preoptic area (anterior to the body of the anterior commissure). Following more caudal medial preoptic area injections (body of the anterior commissure to the suprachiasmatic nucleus) the distribution of retrogradely labeled cells in the medial amygdaloid nucleus and the amygdalohippocampal area revealed no topographic organization of the amygdalopreoptic connections. When amygdaloid neurons were labeled, the amygdalohippocampal area contained two to five times as many HRP-filled cells as the medial amygdaloid nucleus. Retrogradely transported HRP could be followed from the medial preoptic area to the amygdala through fibers in the dorsomedial quadrant of the stria terminalis. In addition, electrolytic lesions of the stria terminalis prior to iontophoresis of HRP into the medial preoptic area prevented retrograde transport to neurons in both the dorsocaudal medial amygdaloid nucleus and the amygdalohippocampal area. These results confirm earlier observations describing the location of autoradiographically labeled efferents from the medial amygdaloid nucleus to the medial preoptic area and provide new information about the restricted region within the medial amygdaloid nucleus from which these projections arise. They also suggest that, unlike the projections from the medial amygdaloid nucleus to the bed nucleus of the stria terminalis, the efferents to the medial preoptic area travel entirely in the stria terminalis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50043/1/902800106_ftp.pd
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