Ankyloglossie chez le nourrisson Anderson, Josdalyne; Prabhu, Pooja; Graham, M. Elise
CMAJ. Canadian Medical Association journal,
02/2024, Volume:
196, Issue:
5
Journal Article
Apnee obstructive du sommeil pediatrique Bhatt, Ayushi; St-Laurent, Aaron; Graham, M. Elise
CMAJ. Canadian Medical Association journal,
06/2024, Volume:
196, Issue:
22
Journal Article
Modern cameras typically use an array of millions of detector pixels to capture images. By contrast, single-pixel cameras use a sequence of mask patterns to filter the scene along with the ...corresponding measurements of the transmitted intensity which is recorded using a single-pixel detector. This review considers the development of single-pixel cameras from the seminal work of Duarte et al. up to the present state of the art. We cover the variety of hardware configurations, design of mask patterns and the associated reconstruction algorithms, many of which relate to the field of compressed sensing and, more recently, machine learning. Overall, single-pixel cameras lend themselves to imaging at non-visible wavelengths and with precise timing or depth resolution. We discuss the suitability of single-pixel cameras for different application areas, including infrared imaging and 3D situation awareness for autonomous vehicles.
A
bstract
The geometric description of gravitational memory for strong gravitational waves is developed, with particular focus on shockwaves and their spinning analogues, gyratons. Memory, which may ...be of position or velocity-encoded type, characterises the residual separation of neighbouring ‘detector’ geodesics following the passage of a gravitational wave burst, and retains information on the nature of the wave source. Here, it is shown how memory is encoded in the Penrose limit of the original gravitational wave spacetime and a new ‘timelike Penrose limit’ is introduced to complement the original plane wave limit appropriate to null congruences. A detailed analysis of memory is presented for timelike and null geodesic congruences in impulsive and extended gravitational shockwaves of Aichelburg-Sexl type, and for gyratons. Potential applications to gravitational wave astronomy and to quantum gravity, especially infra-red structure and ultra-high energy scattering, are briefly mentioned.
We report the first plausible optical electromagnetic counterpart to a (candidate) binary black hole merger. Detected by the Zwicky Transient Facility, the electromagnetic flare is consistent with ...expectations for a kicked binary black hole merger in the accretion disk of an active galactic nucleus B. McKernan, K. E. S. Ford, I. Bartoset al., Astrophys. J. Lett.884, L50 (2019) and is unlikely <O(0.01%)) due to intrinsic variability of this source. The lack of color evolution implies that it is not a supernova and instead is strongly suggestive of a constant temperature shock. Other false-positive events, such as microlensing ora tidal disruption event, are ruled out or constrained to be <O(0.1%). If the flare is associated withS190521g, we find plausible values of total mass M(BBH) ∼ 100 Mꙩ, kick velocity v(k) ∼ 200 km/s at θ ∼ 60° in a disk with aspect ratio H/a ∼ 0.01(i.e., disk height H at radius a) and gas density ρ ∼ 10^(−10)g/cu.cm. The merger could have occurred at a disk migration trap (a ∼ 700 r(g); r(g) ≡ GM(SMBH)/sq.c, where M(SMBH) is the mass of the active galactic nucleus supermassive black hole). The combination of parameters implies a significant spin for at least one of the black holes in S190521g. The timing of our spectroscopy prevents useful constraints on broad-line asymmetry due to an off-center flare. We predict a repeat flare in this source due to a reencountering with the disk in ∼ 1.6 yr(M(SMBH)/10^(8) Mꙩ)(a/10^(3)r(g))^(3/2).
Supermassive black hole binaries (SMBHBs) at sub-parsec separations should be common in galactic nuclei, as a result of frequent galaxy mergers. Hydrodynamical simulations of circum-binary discs ...predict strong periodic modulation of the mass accretion rate on time-scales comparable to the orbital period of the binary. As a result, SMBHBs may be recognized by the periodic modulation of their brightness. We conducted a statistical search for periodic variability in a sample of 35 383 spectroscopically confirmed quasars in the photometric data base of the Palomar Transient Factory (PTF). We analysed Lomb–Scargle periodograms and assessed the significance of our findings by modelling each individual quasar's variability as a damped random walk (DRW). We identified 50 quasars with significant periodicity beyond the DRW model, typically with short periods of a few hundred days. We find 33 of these to remain significant after a re-analysis of their periodograms including additional optical data from the intermediate-PTF and the Catalina Real-Time Transient Survey. Assuming that the observed periods correspond to the redshifted orbital periods of SMBHBs, we conclude that our findings are consistent with a population of unequal-mass SMBHBs, with a typical mass ratio as low as q ≡ M
2/M
1 ≈ 0.01.
The Zwicky Transient Facility (ZTF) is performing a three-day cadence survey of the visible northern sky (∼3π) with newly found transient candidates announced via public alerts. The ZTF Bright ...Transient Survey (BTS) is a large spectroscopic campaign to complement the photometric survey. BTS endeavors to spectroscopically classify all extragalactic transients with mpeak ≤ 18.5 mag in either the gZTF or rZTF filters, and publicly announce said classifications. BTS discoveries are predominantly supernovae (SNe), making this the largest flux-limited SN survey to date. Here we present a catalog of 761 SNe, classified during the first nine months of ZTF (2018 April 1-2018 December 31). We report BTS SN redshifts from SN template matching and spectroscopic host-galaxy redshifts when available. We analyze the redshift completeness of local galaxy catalogs, the redshift completeness fraction (RCF; the ratio of SN host galaxies with known spectroscopic redshift prior to SN discovery to the total number of SN hosts). Of the 512 host galaxies with SNe Ia, 227 had previously known spectroscopic redshifts, yielding an RCF estimate of 44% 4%. The RCF decreases with increasing distance and decreasing galaxy luminosity (for z < 0.05, or ∼200 Mpc, RCF 0.6). Prospects for dramatically increasing the RCF are limited to new multifiber spectroscopic instruments or wide-field narrowband surveys. Existing galaxy redshift catalogs are only ∼50% complete at r 16.9 mag. Pushing this limit several magnitudes deeper will pay huge dividends when searching for electromagnetic counterparts to gravitational wave events or sources of ultra-high-energy cosmic rays or neutrinos.
Five things to know about breastfeeding are presented. Breastfeeding patients should be adequately hydrated before surgery to maintain their breastmilk supply. Lactating patients are at increased ...risk for mastitis during hospital admission. Clinicians should not advise patients to "pump and dump" after anesthesia. Breastfeeding patients should be reunited with their infants as soon as safely possible. Multimodal analgesia, including regional techniques, is suggested for patients who are lactating.
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