276 research outputs found
Local Finance: A Brief Constitutional History
This Comment traces the constitutional history of local finance from the seventeeth century through the present. The authors conclude that the New York City Bar Association Committee on Municipal Affairs\u27 report places the New York State Legislature at a crossroad in its history of dealing with local finances, and the well travelled path of patchwork amendment and politically expedient compromise is unacceptable for the future in light of New York City\u27s recent fiscal problems. However, the authors recognize that the alternative may be politically dangerous to members of the legislature hiding from the challenge and may jeopardize the fiscal stability of New York City and its sister municipalities across New York State
Unveiling the nature of galactic TeV sources with IceCube results
IceCube collaboration reported the first high-significance observation of the
neutrino emission from the Galactic disk. The observed signal can be due to
diffuse emission produced by cosmic rays interacting with interstellar gas but
can also arise from a population of sources. In this paper, we evaluate both
the diffuse and source contribution by taking advantage of gamma-ray
observations and/or theoretical considerations. By comparing our expectations
with IceCube measurement, we constrain the fraction of Galactic TeV gamma-ray
sources (resolved and unresolved) with hadronic nature. In order to be
compatible with the IceCube results, this fraction should be less than corresponding to a cumulative source flux integrated in the 1-100 TeV energy range
End-to-end binaural sound localisation from the raw waveform
A novel end-to-end binaural sound localisation approach is proposed which estimates the azimuth of a sound source directly from the waveform. Instead of employing hand-crafted features commonly employed for binaural sound localisation, such as the interaural time and level difference, our end-to-end system approach uses a convolutional neural network (CNN) to extract specific features from the waveform that are suitable for localisation. Two systems are proposed which differ in the initial frequency analysis stage. The first system is auditory-inspired and makes use of a gammatone filtering layer, while the second system is fully data-driven and exploits a trainable convolutional layer to perform frequency analysis. In both systems, a set of dedicated convolutional kernels are then employed to search for specific localisation cues, which are coupled with a localisation stage using fully connected layers. Localisation experiments using binaural simulation in both anechoic and reverberant environments show that the proposed systems outperform a state-of-the-art deep neural network system. Furthermore, our investigation of the frequency analysis stage in the second system suggests that the CNN is able to exploit different frequency bands for localisation according to the characteristics of the reverberant environment
Detection of activity and position of speakers by using deep neural networks and acoustic data augmentation
The task of Speaker LOCalization (SLOC) has been the focus of numerous works in the research field, where SLOC is performed on pure speech data, requiring the presence of an Oracle Voice Activity Detection (VAD) algorithm. Nevertheless, this perfect working condition is not satisfied in a real world scenario, where employed VADs do commit errors. This work addresses this issue with an extensive analysis focusing on the relationship between several data-driven VAD and SLOC models, finally proposing a reliable framework for VAD and SLOC. The effectiveness of the approach here discussed is assessed against a multi-room scenario, which is close to a real-world environment. Furthermore, up to the authors’ best knowledge, only one contribution proposes a unique framework for VAD and SLOC acting in this addressed scenario; however, this solution does not rely on data-driven approaches.
This work comes as an extension of the authors’ previous research addressing the VAD and SLOC tasks, by proposing numerous advancements to the original neural network architectures. In details, four different models based on convolutional neural networks (CNNs) are here tested, in order to easily highlight the advantages of the introduced novelties. In addition, two different CNN models go under study for SLOC. Furthermore, training of data-driven models is here improved through a specific data augmentation technique. During this procedure, the room impulse responses (RIRs) of two virtual rooms are generated from the knowledge of the room size, reverberation time and microphones and sources placement. Finally, the only other framework for simultaneous detection and localization in a multi-room scenario is here taken into account to fairly compare the proposed method.
As result, the proposed method is more accurate than the baseline framework, and remarkable improvements are specially observed when the data augmentation techniques are applied for both the VAD and SLOC tasks
Setting an upper limit for the total TeV neutrino flux from the disk of our Galaxy
We set an upper limit for the total TeV neutrino flux expected from the disk
of our Galaxy in the region and probed by the
ANTARES experiment. We include both the diffuse emission, due to the
interaction of cosmic rays with the interstellar medium, and the possible
contribution produced by gamma-ray Galactic sources. The neutrino diffuse
emission is calculated under different assumptions for the cosmic ray spatial
and energy distribution in our Galaxy. In particular, we assume that the total
gamma-ray flux produced by all the sources, resolved and unresolved by
H.E.S.S., is produced via hadronic interaction and, hence, is coupled with
neutrino emission. We compare our total neutrino flux with the recent ANTARES
measurement of the neutrino from the Galactic Ridge. We show that the ANTARES
best-fit flux requires the existence of a large source component, close to or
even larger than the most optimistic predictions obtained with our approach
Unresolved sources naturally contribute to PeV -ray diffuse emission observed by Tibet AS
The Tibet AS experiment provided the first measurement of the total
diffuse gamma-ray emission from the Galactic disk in the sub-PeV energy range.
Based on the analysis of TeV sources included in the HGPS catalog, we predict
the expected contribution of unresolved sources in the two angular windows of
the Galactic plane observed by Tibet AS. We show that the sum of this
additional diffuse component due to unresolved sources and the truly diffuse
emission, due to cosmic ray interaction with the interstellar medium, well
saturates the Tibet data, without the need to introduce a progressive hardening
of the cosmic-ray spectrum toward the Galactic center
Ethylene and Chitosan Affected the Seed Yield Components of Onion Depending More on the Dose than Timing of Application
(1) Background: the production of onion seeds is limited by the competition between seeds and the vegetative organs and by scape lodging. However, information on the effects of plant growth regulation on onion seed production is scarce. Aim of the present study was to evaluate the seed yield components and germination ability of onion seeds as affected by the timing and dose of an ethylene application, a plant growth regulator able to modulate shoot–flower competition; and chitosan, an elicitor of plant defense mechanisms able to increase its tolerance to various stresses. (2) Methods: Onion was treated with ethylene at the recommended dose (100% RD) of a commercial product, at 150% RD in two contrasting phenological phases or untreated (control), or ‘with’ or ‘without’ chitosan, and the seed yield components and germination trend were measured. (3) Results: 100% RD at an early phase of growth did not influence the seed yield and increased the thousand seed weight (TSW) by 3.2%. The application of 150% RD decreased the seed yield by 33.5%, and this occurred irrespective of the timing of application. Such decreases were due to a reduction in the number of seeds per flower. The application of chitosan did not affect the crop at 100% RD and increased the seed yield and slightly increased, but not significantly, the TSW under 150% RD. Germination of the fresh seed was 92%, and 17 months of aging reduced it by 14%, with no effects of the treatments on the germination pattern. (4) Conclusions: the ethylene application mostly affected TSW but not the yield, whereas high doses of ethylene reduced yields irrespective of the timing of application. Such a result may have been due to a delay in the flowering onset that occurred in a relatively dry month. Chitosan sustained its yield when the yield potential was reduced by 150% RD, and such a result was likely due to physical protection from the transpiration since the synthetic fungicides applied did not likely allow the pathogens to infections. These results have implications for establishing the timing and dose of application of plant growth regulators and elicitors in seed onions to sustain the seed quality
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