834 research outputs found
Phases of New Physics in the CMB
Fluctuations in the cosmic neutrino background are known to produce a phase
shift in the acoustic peaks of the cosmic microwave background. It is through
the sensitivity to this effect that the recent CMB data has provided a robust
detection of free-streaming neutrinos. In this paper, we revisit the phase
shift of the CMB anisotropy spectrum as a probe of new physics. The phase shift
is particularly interesting because its physical origin is strongly constrained
by the analytic properties of the Green's function of the gravitational
potential. For adiabatic fluctuations, a phase shift requires modes that
propagate faster than the speed of fluctuations in the photon-baryon plasma.
This possibility is realized by free-streaming relativistic particles, such as
neutrinos or other forms of dark radiation. Alternatively, a phase shift can
arise from isocurvature fluctuations. We present simple models to illustrate
each of these effects. We then provide observational constraints from the
Planck temperature and polarization data on additional forms of radiation. We
also forecast the capabilities of future CMB Stage IV experiments. Whenever
possible, we give analytic interpretations of our results.Comment: 39 pages, 10 figures, 5 tables; v2: minor corrections, references
added; v3: corrected Planck parameter constraints, conclusions unchange
Speech Sensorimotor Learning through a Virtual Vocal Tract
Studies of speech sensorimotor learning often manipulate auditory feedback by modifying isolated acoustic parameters such as formant frequency or fundamental frequency using near real-time resynthesis of a participant\u27s speech. An alternative approach is to engage a participant in a total remapping of the sensorimotor working space using a virtual vocal tract. To support this approach for studying speech sensorimotor learning we have developed a system to control an articulatory synthesizer using electromagnetic articulography data. Articulator movement data from the NDI Wave System are streamed to a Maeda articulatory synthesizer. The resulting synthesized speech provides auditory feedback to the participant. This approach allows the experimenter to generate novel articulatory-acoustic mappings. Moreover, the acoustic output of the synthesizer can be perturbed using acoustic resynthesis methods. Since no robust speech-acoustic signal is required from the participant, this system will allow for the study of sensorimotor learning in any individuals, even those with severe speech disorders. In the current work we present preliminary results that demonstrate that typically-functioning participants can use a virtual vocal tract to produce diphthongs within a novel articulatory-acoustic workspace. Once sufficient baseline performance is established, perturbations to auditory feedback (formant shifting) can elicit compensatory and adaptive articulatory responses
Cosmology with Rayleigh scattering of the cosmic microwave background
The cosmic microwave background (CMB) has been a treasure trove for
cosmology. Over the next decade, current and planned CMB experiments are
expected to exhaust nearly all primary CMB information. To further constrain
cosmological models, there is a great benefit to measuring signals beyond the
primary modes. Rayleigh scattering of the CMB is one source of additional
cosmological information. It is caused by the additional scattering of CMB
photons by neutral species formed during recombination and exhibits a strong
and unique frequency scaling (). We will show that with
sufficient sensitivity across frequency channels, the Rayleigh scattering
signal should not only be detectable but can significantly improve constraining
power for cosmological parameters, with limited or no additional modifications
to planned experiments. We will provide heuristic explanations for why certain
cosmological parameters benefit from measurement of the Rayleigh scattering
signal, and confirm these intuitions using the Fisher formalism. In particular,
observation of Rayleigh scattering allows significant improvements on
measurements of and .Comment: 20 pages, 10 figure
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Serial Interval of COVID-19 among Publicly Reported Confirmed Cases.
We estimate the distribution of serial intervals for 468 confirmed cases of coronavirus disease reported in China as of February 8, 2020. The mean interval was 3.96 days (95% CI 3.53-4.39 days), SD 4.75 days (95% CI 4.46-5.07 days); 12.6% of case reports indicated presymptomatic transmission
Treatment utilization and outcomes in elderly patients with locally advanced esophageal carcinoma: A review of the National Cancer Database
For elderly patients with locally advanced esophageal cancer, therapeutic approaches and outcomes in a modern cohort are not well characterized. Patients â„70Â years old with clinical stage II and III esophageal cancer diagnosed between 1998 and 2012 were identified from the National Cancer Database and stratified based on treatment type. Variables associated with treatment utilization were evaluated using logistic regression and survival evaluated using Cox proportional hazards analysis. Propensity matching (1:1) was performed to help account for selection bias. A total of 21,593 patients were identified. Median and maximum ages were 77 and 90, respectively. Treatment included palliative therapy (24.3%), chemoradiation (37.1%), trimodality therapy (10.0%), esophagectomy alone (5.6%), or no therapy (12.9%). Age â„80 (OR 0.73), female gender (OR 0.81), Charlson-Deyo comorbidity score â„2 (OR 0.82), and high-volume centers (OR 0.83) were associated with a decreased likelihood of palliative therapy versus no treatment. Age â„80 (OR 0.79) and Clinical Stage III (OR 0.33) were associated with a decreased likelihood, while adenocarcinoma histology (OR 1.33) and nonacademic cancer centers (OR 3.9), an increased likelihood of esophagectomy alone compared to definitive chemoradiation. Age â„80 (OR 0.15), female gender (OR 0.80), and non-Caucasian race (OR 0.63) were associated with a decreased likelihood, while adenocarcinoma histology (OR 2.10) and high-volume centers (OR 2.34), an increased likelihood of trimodality therapy compared to definitive chemoradiation. Each treatment type demonstrated improved survival compared to no therapy: palliative treatment (HR 0.49) to trimodality therapy (HR 0.25) with significance between all groups. Any therapy, including palliative care, was associated with improved survival; however, subsets of elderly patients with locally advanced esophageal cancer are less likely to receive aggressive therapy. Care should be taken to not unnecessarily deprive these individuals of treatment that may improve survival
Estimating the Impact of foregrounds on the Future Detection of Rayleigh scattering
Rayleigh scattering of the cosmic microwave background (CMB) by neutral
hydrogen shortly after recombination leaves frequency-dependent imprints on
intensity and polarization fluctuations. High signal-to-noise observations of
CMB Rayleigh scattering would provide additional insight into the physics of
recombination, including greater constraining power for parameters like the
primordial helium fraction, the light relic density, and the sum of neutrino
masses. However, such a measurement of CMB Rayleigh scattering is challenging
due to the presence of astrophysical foregrounds, which are more intense at the
high frequencies, where the effects of Rayleigh scattering are most prominent.
Here we forecast the detectability of CMB Rayleigh scattering including
foreground removal using blind internal linear combination methods for a set of
near-future surveys. We show that atmospheric effects for ground-based
observatories and astrophysical foregrounds pose a significant hindrance to
detecting CMB Rayleigh scattering with experiments planned for this decade,
though a high-significance measurement should be possible with a future CMB
satellite.Comment: 14 pages, 12 figure
Risk for Transportation of Coronavirus Disease from Wuhan to Other Cities in China.
On January 23, 2020, China quarantined Wuhan to contain coronavirus disease (COVID-19). We estimated the probability of transportation of COVID-19 from Wuhan to 369 other cities in China before the quarantine. Expected COVID-19 risk is >50% in 130 (95% CI 89-190) cities and >99% in the 4 largest metropolitan areas
Short-term emission line and continuum variations in Mrk110
We present results of a variability campaign of Mrk110 performed with the
9.2-m Hobby-Eberly Telescope (HET) at McDonald Observatory. The high S/N
spectra cover most of the optical range. They were taken from 1999 November
through 2000 May. The average interval between the observations was 7.3 days
and the median interval was only 3.0 days. Mrk110 is a narrow-line Seyfert 1
galaxy. During our campaign the continuum flux was in a historically low stage.
Considering the delays of the emission lines with respect to the continuum
variations we could verify an ionization stratification of the BLR. We derived
virial masses of the central black hole from the radial distances of the
different emission lines and from their widths. The calculated central masses
agree within 20%. Furthermore, we identified optical HeI singlet emission lines
emitted in the broad-line region. The observed line fluxes agree with
theoretical predictions. We show that a broad wing on the red side of the
[OIII]5007 line is caused by the HeI singlet line at 5016A.Comment: 11 pages, 16 figures, A&A Latex. Accepted for publication in A&A Main
Journa
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