The objectives were to examine effects of dietary Se supplementation and nutrient restriction during defined periods of gestation on maternal adaptations to pregnancy in primigravid sheep. Sixty-four ...pregnant Western Whiteface ewe lambs were assigned to treatments in a 2 x 4 factorial design. Treatments were dietary Se adequate Se (ASe; 3.05 μg/kg of BW) vs. high Se (HSe; 70.4 μg/kg of BW) fed as Se-enriched yeast, and plane of nutrition control (C; 100% of NRC requirements) vs. restricted (R; 60% of NRC requirements. Selenium treatments were fed throughout gestation. Plane of nutrition treatments were applied during mid (d 50 to 90) and late gestation (d 90 to 130), which resulted in 4 distinct plane of nutrition treatments treatment: CC (control from d 50 to 130), RC (restricted from d 50 to 90, and control d 90 to 130), CR (control from d 50 to 90, and restricted from d 90 to 130), and RR (restricted from d 50 to 130). All of the pregnant ewes were necropsied on d 132 ± 0.9 of gestation (length of gestation almost equal to145 d). Nutrient restriction treatments decreased ewe ADG and G:F, as a result, RC and CR ewes had similar BW and maternal BW (MBW) at necropsy, whereas RR ewes were lighter than RC and CR ewes. From d 90 to 130, the HSe-CC ewes had greater ADG (Se x nutrition; P = 0.05) than did ASe-CC ewes, whereas ADG and G:F (Se x nutrition; P = 0.08) were less for HSe-RR ewes compared with ASe-RR ewes. The CR and RR treatments decreased total gravid uterus weight (P = 0.01) as well as fetal weight (P = 0.02) compared with RC and CC. High Se decreased total (g; P = 0.09) and relative heart mass (g/kg of MBW; P = 0.10), but increased total and relative mass of liver (P less-than or equal to 0.05) and perirenal fat (P less-than or equal to 0.06) compared with ASe. Total stomach complex mass was decreased (P < 0.01) by all the nutrient restriction treatments, but was reduced to a greater extent in CR and RR compared with RC. Total small intestine mass was similar between RC and CC ewes, but was markedly reduced (P < 0.01) in CR and RR ewes. The mass of the stomach complex and the small and large intestine relative to MBW was greater (P = 0.01) for RC than for CR ewes. Increased Se decreased jejunal DNA concentration (P = 0.07), total jejunal cell number (P = 0.03), and total proliferating jejunal cell number (P = 0.05) compared with ASe. These data indicate that increased dietary Se affected whole-body and organ growth of pregnant ewes, but the results differed depending on the plane of nutrition. In addition, the timing and duration of nutrient restriction relative to stage of pregnancy affected visceral organ mass in a markedly different fashion.
To examine effects of maternal nutrition and Se intake on adiposity and insulin sensitivity in female offspring, treatments were imposed during gestation on 82 pregnant primiparous Rambouillet ewe ...lambs (52.2 ± 0.8 kg) allotted randomly to 1 of 6 treatments in a 2 × 3 factorial arrangement. Factors were adequate (9.5 μg Se
·
kg BW
−1
·
d
−1; ASe) or high (81.8 μg Se
·
kg BW
−1
·
d
−1; HSe) levels of dietary Se (Se-enriched yeast) and maternal nutritional intake (100% of metabolizable energy ME requirement MOD, 60% of MOD LOW, and 140% of MOD HIGH). Selenium treatments were initiated at breeding and global nutritional treatments at day 50 of gestation. At parturition, lambs were removed from ewes before nursing and managed similarly. Glucose tolerance tests were performed at 107 and 148 d of age. Necropsies were performed at 180 d of age. Although there was no effect of Se on maternal body condition or weight during gestation, both maternal nutritional intake and selenium treatment influenced (
P ≤ 0.04) offspring growth and response to a glucose tolerance test. Female lambs from HSe ewes were heavier (
P = 0.04) at birth. There were nutritional intake and Se interactions (
P ≤ 0.05) on the growth rate of the lambs and their insulin response to a glucose bolus at 2 different times during growth. By 180 d, ewe lambs from HSe ewes had more (
P ≤ 0.07) internal fat stores than lambs from ASe ewes. It appears that both maternal nutritional level and Se intake can influence insulin sensitivity, and maternal Se intake alone can enhance fat deposition in female offspring.
We present the results of our power spectral density analysis for the BL Lac object OJ 287, utilizing the Fermi-LAT survey at high-energy γ-rays, Swift-XRT in X-rays, several ground-based telescopes ...and the Kepler satellite in the optical, and radio telescopes at GHz frequencies. The light curves are modeled in terms of continuous-time autoregressive moving average (CARMA) processes. Owing to the inclusion of the Kepler data, we were able to construct for the first time the optical variability power spectrum of a blazar without any gaps across ∼6 dex in temporal frequencies. Our analysis reveals that the radio power spectra are of a colored-noise type on timescales ranging from tens of years down to months, with no evidence for breaks or other spectral features. The overall optical power spectrum is also consistent with a colored noise on the variability timescales ranging from 117 years down to hours, with no hints of any quasi-periodic oscillations. The X-ray power spectrum resembles the radio and optical power spectra on the analogous timescales ranging from tens of years down to months. Finally, the γ-ray power spectrum is noticeably different from the radio, optical, and X-ray power spectra of the source: we have detected a characteristic relaxation timescale in the Fermi-LAT data, corresponding to ∼150 days, such that on timescales longer than this, the power spectrum is consistent with uncorrelated (white) noise, while on shorter variability timescales there is correlated (colored) noise.
Results from regular monitoring of relativistic compact binaries like PSR 1913+16 are consistent with the dominant (quadrupole) order emission of gravitational waves (GWs). We show that observations ...associated with the binary black hole (BBH) central engine of blazar OJ 287 demand the inclusion of gravitational radiation reaction effects beyond the quadrupolar order. It turns out that even the effects of certain hereditary contributions to GW emission are required to predict impact flare timings of OJ 287. We develop an approach that incorporates this effect into the BBH model for OJ 287. This allows us to demonstrate an excellent agreement between the observed impact flare timings and those predicted from ten orbital cycles of the BBH central engine model. The deduced rate of orbital period decay is nine orders of magnitude higher than the observed rate in PSR 1913+16, demonstrating again the relativistic nature of OJ 287's central engine. Finally, we argue that precise timing of the predicted 2019 impact flare should allow a test of the celebrated black hole "no-hair theorem" at the 10% level.
ABSTRACT OJ 287 is a quasi-periodic quasar with roughly 12 year optical cycles. It displays prominent outbursts that are predictable in a binary black hole model. The model predicted a major optical ...outburst in 2015 December. We found that the outburst did occur within the expected time range, peaking on 2015 December 5 at magnitude 12.9 in the optical R-band. Based on Swift/XRT satellite measurements and optical polarization data, we find that it included a major thermal component. Its timing provides an accurate estimate for the spin of the primary black hole, . The present outburst also confirms the established general relativistic properties of the system such as the loss of orbital energy to gravitational radiation at the 2% accuracy level, and it opens up the possibility of testing the black hole no-hair theorem with 10% accuracy during the present decade.
Context.
The close approach of the near-Earth asteroid (99942) Apophis to Earth in 2029 will provide a unique opportunity to examine how the physical properties of the asteroid could be changed due ...to the Earth’s gravitational perturbation. As a result, the Republic of Korea is planning a rendezvous mission to Apophis.
Aims.
Our aim was to use photometric data from the apparitions in 2020−2021 to refine the shape model and spin state of Apophis.
Methods.
Using thirty-six 1- to 2-meter-class ground-based telescopes and the Transiting Exoplanet Survey Satellite, we carried out a photometric observation campaign throughout the 2020−2021 apparition. The convex shape model and spin state were refined using the light-curve inversion method.
Results.
According to our best-fit model, Apophis is rotating in a short-axis mode with rotation and precession periods of 264.178 h and 27.38547 h, respectively. The angular momentum vector orientation of Apophis was found to be (275°, −85°) in the ecliptic coordinate system. The ratio of the dynamic moments of inertia of this asteroid was fitted to
I
a
:
I
b
:
I
c
= 0.64 : 0.97 : 1, which corresponds to an elongated prolate ellipsoid. These findings regarding the spin state and shape model can be used to both design the space mission scenario and investigate the impact of the Earth’s tidal force during close encounters.
Blazar OJ287 exhibits large thermal flares at least twice every 12 years. The times of these flares have been predicted successfully using the model of a quasi-Keplerian eccentric black hole binary ...where the secondary impacts the accretion disk of the primary, creating the thermal flares. New measurements of the historical light curve have been combined with the observations of the 2015 November/December flare to identify the impact record since year 1886, and to constrain the orbit of the binary. The orbital solution shows that the binary period, now 12.062 years, is decreasing at the rate of 36 days per century. This corresponds to an energy loss to gravitational waves that is 6.5 ± 4 % less than the rate predicted by the standard quadrupolar gravitational wave (GW) emission. We show that the difference is due to higher order gravitational radiation reaction terms that include the dominant order tail contributions.
We present results from an observational campaign on the close binary system 2MASS J16211735+4412541 and a preliminary model based on the photometric data gathered during the quiescent and outburst ...levels. The modeling, done with the Wilson-Devinney code and its improvements, failed to reproduce the observational properties of the system. A secondary minimum obtained within the stellar model that is too shallow, as well as the evidence provided by the spectroscopic observations performed at outburst and quiescence, point toward an accretion disk surrounding one component, likely a white dwarf, as the cause of the outburst. Using a simple disk model, we modeled the observed multicolor light curves taken two (2016 August) and eight (2017 March) months after the outburst. We obtained a reasonable fit to the 2016 August light curves but those from 2017 March cannot be explained with the same parameters. We conclude that J1621 is an eclipsing cataclysmic binary, with an accretion disk still present almost a year after outburst, and not a contact-type system as previously classified. The binary is seen at an inclination of about 84° and there is evidence of changing accretion rates and disk parameters as a result of the outburst. Our results indicate that more cataclysmic variables may be hidden among contact binaries.
To investigate the mechanism by which T regulatory (Treg) cells may control the early onset of autoimmunity, we have used an adoptive transfer model to track Treg, Th, and anti-chromatin B cell ...interactions in vivo. We show that anti-chromatin B cells secrete Abs by day 8 in vivo upon provision of undeviated, Th1- or Th2-type CD4+ T cell help, but this secretion is blocked by the coinjection of CD4+ CD25+ Treg cells. Although Treg cells do not interfere with the initial follicular entry or activation of Th or B cells at day 3, ICOS levels on Th cells are decreased. Furthermore, Treg cells must be administered during the initial phases of the Ab response to exert full suppression of autoantibody production. These studies indicate that CD25+ Treg cells act to inhibit the maturation, rather than the initiation, of autoantibody responses.
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