2,068 research outputs found
The vascularity of the central nervous system in certain vertebrates
Thesis (M.A.)--Boston UniversityThe literature and various theories regarding the vascularity of the central nervous system are reviewed. Particular emphasis is placed on the theories of Craigie (bib l iog.), Sterzi (bibliog.), Hofmann (1900, 1901), Beddard (1905), Kappers (bibliog.), Finley (bibliog.) Cobb (1929), Pfeifer (bibliog.), and Duret (bibliog.).
The thesis deals with the vascularity of parts of the central nervous system in the Pacific dogfish, ratfish, mudpuppy, Tiger salemander, Leopard frog, New Zealand lizard, Apteryx, Rabbit, and,the albino and wild gray Norway rat
On the entanglement of a quantum field with a dispersive medium
In this Letter we study the entanglement of a quantum radiation field
interacting with a dielectric medium. In particular, we describe the quantum
mixed state of a field interacting with a dielectric through plasma and Drude
models and show that these generate very different entanglement behavior, as
manifested in the entanglement entropy of the field. We also present a formula
for a "Casimir" entanglement entropy, i.e., the distance dependence of the
field entropy. Finally, we study a toy model of the interaction between two
plates. In this model, the field entanglement entropy is divergent; however, as
in the Casimir effect, its distance-dependent part is finite, and the field
matter entanglement is reduced when the objects are far.Comment: Final published PRL versio
Anomaly metrics to differentiate threat sources from benign sources in primary vehicle screening.
Discrimination of benign sources from threat sources at Port of Entries (POE) is of a great importance in efficient screening of cargo and vehicles using Radiation Portal Monitors (RPM). Currently RPM's ability to distinguish these radiological sources is seriously hampered by the energy resolution of the deployed RPMs. As naturally occurring radioactive materials (NORM) are ubiquitous in commerce, false alarms are problematic as they require additional resources in secondary inspection in addition to impacts on commerce. To increase the sensitivity of such detection systems without increasing false alarm rates, alarm metrics need to incorporate the ability to distinguish benign and threat sources. Principal component analysis (PCA) and clustering technique were implemented in the present study. Such techniques were investigated for their potential to lower false alarm rates and/or increase sensitivity to weaker threat sources without loss of specificity. Results of the investigation demonstrated improved sensitivity and specificity in discriminating benign sources from threat sources
Entangled coherent states by mixing squeezed vacuum and coherent light
Entangled coherent states are shown to emerge, with high fidelity, when
mixing coherent and squeezed vacuum states of light on a beam-splitter. These
maximally entangled states, where photons bunch at the exit of a beamsplitter,
are measured experimentally by Fock-state projections. Entanglement is examined
theoretically using a Bell-type nonlocality test and compared with ideal
entangled coherent states. We experimentally show nearly perfect similarity
with entangled coherent states for an optimal ratio of coherent and squeezed
vacuum light. In our scheme, entangled coherent states are generated
deterministically with small amplitudes, which could be beneficial, for
example, in deterministic distribution of entanglement over long distances.Comment: 6 pages, 6 figures, comments are welcom
Evaluation of Deep-Learning-Based Voice Activity Detectors and Room Impulse Response Models in Reverberant Environments
State-of-the-art deep-learning-based voice activity detectors (VADs) are
often trained with anechoic data. However, real acoustic environments are
generally reverberant, which causes the performance to significantly
deteriorate. To mitigate this mismatch between training data and real data, we
simulate an augmented training set that contains nearly five million
utterances. This extension comprises of anechoic utterances and their
reverberant modifications, generated by convolutions of the anechoic utterances
with a variety of room impulse responses (RIRs). We consider five different
models to generate RIRs, and five different VADs that are trained with the
augmented training set. We test all trained systems in three different real
reverberant environments. Experimental results show increase on average
in accuracy, precision and recall for all detectors and response models,
compared to anechoic training. Furthermore, one of the RIR models consistently
yields better performance than the other models, for all the tested VADs.
Additionally, one of the VADs consistently outperformed the other VADs in all
experiments.Comment: Accepted to ICASSP 202
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