Background. There is evidence to support that nutritional deficiency can reduce the body's immune function, thereby decreasing resistance to disease and increasing susceptibility to intestinal ...parasites. Methods. A cross-sectional survey was carried out on 693 school-aged children from 5 schistosomiasis-endemic villages in Northern Samar, the Philippines. Data on dietary intake, nutritional status, and intestinal parasitic infection were collected. Results. The prevalence of stunting, thinness, and wasting was 49.2%, 27.8%, and 59.7% of all children. The proportion of children infected with Schistosoma japonicum (15.6%, P = .03) and hookworm (22.0%, P = .05) were significantly lower among children who met the recommended energy and nutrient intake (RENI) for total calories. The percentage of children infected with Trichuris trichiura was highest among children who did not meet the RENI for energy (74.1%, P = .04), iron (73.4%, P = .01), thiamine (74.0%, P = .00), and riboflavin (73.3%, P = .01). Susceptibility to having 1 or more parasitic infections was significantly associated with poor intake of energy (P = .04), thiamine (P = .02), and riboflavin (P = .01). The proportion of stunted children was significantly higher among children who did not meet the RENI for energy (68.9%, P = .002), protein (54.0%, P = .004), or niacin (30.8%, P = .02) and for those infected with hookworm (31.8%, P = .0002). After adjusting for potential confounders, protein intake less than the RENI (odds ratio OR, 1.48; 95% confidence interval CI, 1.03–2.14), and hookworm infection (OR, 1.77; 95% CI, 1.22–2.55) were the major predictors of stunting. Conclusions. The results support the hypothesis that poor nutrient intake may increase susceptibility to parasitic diseases and together they negatively affect childhood nutritional status.
Accretion disks around supermassive black holes (SMBHs) are promising sites for stellar mass black hole (BH) mergers due to mass segregation and merger acceleration by disk gas torques. Here we show ...that a gravitational-wave (GW) kick at BH merger causes ram-pressure stripping of gas within the BH Hill sphere. If RH ≥ H, the disk height, an off-center UV flare at aBH ∼ 103rg, emerges within tUV ∼ O(2 days)(aBH/103rg)(MSMBH/108M )(vkick/102 km s−1) postmerger and lasts O(RH/vkick) ∼ O(5tUV). The flare emerges with luminosity O(1042erg s−1)(tUV/2days)−1(MHill/1M )(vkick/102 km s−1)2. Active galactic nucleus optical/UV photometry is altered and asymmetric broad emission line profiles can develop after weeks. If RH < H, detectability depends on disk optical depth. Follow-up by large optical sky surveys is optimized for small GW error volumes and for Laser Interferometer Gravitational-Wave Observatory/Virgo triggers >50M .
We present the first results from an ongoing survey for damped Lyman-α systems (DLAs) in the spectra of z > 2 quasars observed in the course of the Baryon Oscillation Spectroscopic Survey (BOSS), ...which is part of the Sloan Digital Sky Survey (SDSS) III. Our full (non-statistical) sample, based on Data Release 9, comprises 12 081 systems with log N(H i) ≥ 20, out of which 6839 have log N(H i) ≥ 20.3. This is the largest DLA sample ever compiled, superseding that from SDSS-II by a factor of seven. Using a statistical sub-sample and estimating systematics from realistic mock data, we probe the N(H i) distribution at ⟨z⟩ = 2.5. Contrary to what is generally believed, the distribution extends beyond 1022 cm-2 with a moderate slope of index ≈−3.5. This result matches the opacity-corrected distribution observed at z = 0 surprisingly well. The cosmological mass density of neutral gas in DLAs is found to be \hbox{$\omegagdla \approx 10^{-3}$}ΩgDLA≈10-3, evolving only mildly over the past 12 billion years.
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).
We investigate the cosmological implications of the latest growth of structure measurement from the Baryon Oscillation Spectroscopic Survey (BOSS) CMASS Data Release 11 with particular focus on the ...sum of the neutrino masses, ∑m
ν. We examine the robustness of the cosmological constraints from the baryon acoustic oscillation (BAO) scale, the Alcock–Paczynski effect and redshift-space distortions (D
V/r
s, F
AP, fσ8) of Beutler et al., when introducing a neutrino mass in the power spectrum template. We then discuss how the neutrino mass relaxes discrepancies between the cosmic microwave background (CMB) and other low-redshift measurements within Λ cold dark matter. Combining our cosmological constraints with 9-year Wilkinson Microwave Anisotropy Probe (WMAP9) yields ∑m
ν = 0.36 ± 0.14 eV (68 per cent c.l.), which represents a 2.6σ preference for non-zero neutrino mass. The significance can be increased to 3.3σ when including weak lensing results and other BAO constraints, yielding ∑m
ν = 0.35 ± 0.10 eV (68 per cent c.l.). However, combining CMASS with Planck data reduces the preference for neutrino mass to ∼2σ. When removing the CMB lensing effect in the Planck temperature power spectrum (by marginalizing over A
L), we see shifts of ∼1σ in σ8 and Ωm, which have a significant effect on the neutrino mass constraints. In the case of CMASS plus Planck without the A
L lensing signal, we find a preference for a neutrino mass of ∑m
ν = 0.34 ± 0.14 eV (68 per cent c.l.), in excellent agreement with the WMAP9+CMASS value. The constraint can be tightened to 3.4σ yielding ∑m
ν = 0.36 ± 0.10 eV (68 per cent c.l.) when weak lensing data and other BAO constraints are included.
ABSTRACT
We present and analyse a new tidal disruption event (TDE), AT2017eqx at redshift z = 0.1089, discovered by Pan-STARRS and ATLAS. The position of the transient is consistent with the nucleus ...of its host galaxy; the spectrum shows a persistent blackbody temperature T ≳ 20 000 K with broad H i and He ii emission; and it peaks at a blackbody luminosity of L ≈ 1044 erg s−1. The lines are initially centred at zero velocity, but by 100 d, the H i lines disappear while the He ii develops a blueshift of ≳ 5000 km s−1. Both the early- and late-time morphologies have been seen in other TDEs, but the complete transition between them is unprecedented. The evolution can be explained by combining an extended atmosphere, undergoing slow contraction, with a wind in the polar direction becoming visible at late times. Our observations confirm that a lack of hydrogen a TDE spectrum does not indicate a stripped star, while the proposed model implies that much of the diversity in TDEs may be due to the observer viewing angle. Modelling the light curve suggests AT2017eqx resulted from the complete disruption of a solar-mass star by a black hole of ∼106.3 M⊙. The host is another Balmer-strong absorption galaxy, though fainter and less centrally concentrated than most TDE hosts. Radio limits rule out a relativistic jet, while X-ray limits at 500 d are among the deepest for a TDE at this phase.
Test particle codes indicate that electron dynamics due to interactions with low amplitude incoherent whistler mode‐waves can be adequately described by quasi‐linear theory. However there is ...significant evidence indicating that higher amplitude waves cause electron dynamics not adequately described using quasi‐linear theory. Using the method that was introduced in Allanson et al. (2019, https://doi.org/10.1029/2019JA027088), we track the dynamical response of electrons due to interactions with incoherent whistler‐mode waves, across all energy and pitch angle space. We conduct five experiments each with different values of the electromagnetic wave amplitude. We find that the electron dynamics agree well with the quasi‐linear theory diffusion coefficients for low amplitude incoherent waves with (Bw,rms/B0)2≈3.7·10−10, over a time scale T of the order of 1,000 gyroperiods. However, the resonant interactions with higher amplitude waves cause significant nondiffusive dynamics as well as diffusive dynamics. When electron dynamics are extracted and analyzed over time scales shorter than T, we are able to isolate both the diffusive and nondiffusive (advective) dynamics. Interestingly, when considered over these appropriately shorter time scales (of the order of hundreds or tens of gyroperiods), the diffusive component of the dynamics agrees well with the predictions of quasi‐linear theory, even for wave amplitudes up to (Bw,rms/B0)2≈5.8·10−6. Quasi‐linear theory is based on fundamentally diffusive dynamics, but the evidence presented herein also indicates the existence of a distinct advective component. Therefore, the proper description of electron dynamics in response to wave‐particle interactions with higher amplitude whistler‐mode waves may require Fokker‐Planck equations that incorporate diffusive and advective terms.
Plain Language Summary
Electromagnetic waves interact strongly with charged particles in the Earth's inner magnetosphere. It is important to be able to model the evolution of these particles, since we rely on the many satellites that orbit within this hazardous radiation environment. Particle dynamics within the Earth's outer radiation belt are usually modelled using a long‐established theory fundamentally based on diffusive dynamics. We effectively benchmark this treatment for some individual cases in which one would expect agreement, that is, lower amplitude waves. We then utilize our novel method to probe cases for which the application of the standard diffusive model is questionable. We find that the resonant interactions with higher amplitude waves result in advective dynamics as well as expected diffusive behavior. When the problem is properly considered, the diffusive component of the dynamics does in fact agree well with the predictions of quasi‐linear theory. However, this is only one component of the dynamics, and one should also consider the advective component. This work motivates the use of model equations that incorporate both diffusive and other nondiffusive terms.
Key Points
Whistler‐mode waves (Bw,rms/B0)2∼O(10−10)−O(10−6) in uniform B give diffusive and advective dynamics
Over appropriately short time scales the diffusive component of the dynamics agrees with quasilinear theory even for highest amplitude waves
These time scales range from thousands to tens of gyroperiods for the lowest and highest amplitude waves, respectively
ABSTRACT
At 66 Mpc, AT2019qiz is the closest optical tidal disruption event (TDE) to date, with a luminosity intermediate between the bulk of the population and the faint-and-fast event iPTF16fnl. ...Its proximity allowed a very early detection and triggering of multiwavelength and spectroscopic follow-up well before maximum light. The velocity dispersion of the host galaxy and fits to the TDE light curve indicate a black hole mass ≈106 M⊙, disrupting a star of ≈1 M⊙. By analysing our comprehensive UV, optical, and X-ray data, we show that the early optical emission is dominated by an outflow, with a luminosity evolution L ∝ t2, consistent with a photosphere expanding at constant velocity (≳2000 km s−1), and a line-forming region producing initially blueshifted H and He ii profiles with v = 3000–10 000 km s−1. The fastest optical ejecta approach the velocity inferred from radio detections (modelled in a forthcoming companion paper from K. D. Alexander et al.), thus the same outflow may be responsible for both the fast optical rise and the radio emission – the first time this connection has been observed in a TDE. The light-curve rise begins 29 ± 2 d before maximum light, peaking when the photosphere reaches the radius where optical photons can escape. The photosphere then undergoes a sudden transition, first cooling at constant radius then contracting at constant temperature. At the same time, the blueshifts disappear from the spectrum and Bowen fluorescence lines (N iii) become prominent, implying a source of far-UV photons, while the X-ray light curve peaks at ≈1041 erg s−1. Assuming that these X-rays are from prompt accretion, the size and mass of the outflow are consistent with the reprocessing layer needed to explain the large optical to X-ray ratio in this and other optical TDEs, possibly favouring accretion-powered over collision-powered outflow models.
Signals from very low frequency (VLF) transmitters can leak from the Earth‐ionosphere wave guide into the inner magnetosphere, where they propagate in the whistler mode and contribute to electron ...dynamics in the inner radiation belt and slot region. Observations show that the waves from each VLF transmitter are highly localized, peaking on the nightside in the vicinity of the transmitter. In this study we use ∼5 years of Van Allen Probes observations to construct global statistical models of the bounce‐averaged pitch angle diffusion coefficients for each individual VLF transmitter, as a function of L*, magnetic local time (MLT), and geographic longitude. We construct a 1‐D pitch angle diffusion model with implicit longitude and MLT dependence to show that VLF transmitter waves weakly scatter electrons into the drift loss cone. We find that global averages of the wave power, determined by averaging the wave power over MLT and longitude, capture the long‐term dynamics of the loss process, despite the highly localized nature of the waves in space. We use our new model to assess the role of VLF transmitter waves, hiss waves, and Coulomb collisions on electron loss in the inner radiation belt and slot region. At moderate relativistic energies, E∼500 keV, waves from VLF transmitters reduce electron lifetimes by an order of magnitude or more, down to the order of 200 days near the outer edge of the inner radiation belt. However, VLF transmitter waves are ineffective at removing multi–megaelectron volt electrons from either the inner radiation belt or slot region.
Key Points
Models of the globally averaged VLF transmitter wave power capture their long‐term contribution to electron loss
VLF transmitter waves can reduce the lifetimes of moderate‐energy electrons, E∼500 keV, by an order of magnitude down to 200 days at L∼1.7
VLF transmitter waves are unable to effectively remove multi–megaelectron volt electrons
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