Abstract
We report results from continued timing observations of PSR J0740+6620, a high-mass, 2.8 ms radio pulsar in orbit with a likely ultracool white dwarf companion. Our data set consists of ...combined pulse arrival-time measurements made with the 100 m Green Bank Telescope and the Canadian Hydrogen Intensity Mapping Experiment telescope. We explore the significance of timing-based phenomena arising from general relativistic dynamics and variations in pulse dispersion. When using various statistical methods, we find that combining ∼1.5 yr of additional, high-cadence timing data with previous measurements confirms and improves on previous estimates of relativistic effects within the PSR J0740+6620 system, with the pulsar mass
m
p
=
2.08
−
0.07
+
0.07
M
⊙
(68.3% credibility) determined by the relativistic Shapiro time delay. For the first time, we measure secular variation in the orbital period and argue that this effect arises from apparent acceleration due to significant transverse motion. After incorporating contributions from Galactic differential rotation and off-plane acceleration in the Galactic potential, we obtain a model-dependent distance of
d
=
1.14
−
0.15
+
0.17
kpc (68.3% credibility). This improved distance confirms the ultracool nature of the white dwarf companion determined from recent optical observations. We discuss the prospects for future observations with next-generation facilities, which will likely improve the precision on
m
p
for J0740+6620 by an order of magnitude within the next few years.
Objective
To assess the current prevalence of and risk factors for infertility among couples of reproductive age in China.
Design
Population‐based cross‐sectional study.
Setting
We approached 25 270 ...couples in eight provinces/municipalities, of whom 18 571 (response rate 74%) were interviewed.
Population
Couples living together and married for more than 1 year, of whom the female spouse was 20–49 years old.
Methods
Women were approached via telephone and face‐to‐face conversation to complete the standardised and structured questionnaire by trained interviewers.
Main outcome measures
Prevalence of and risk factors for infertility.
Results
Among women ‘at risk’ of pregnancy, the prevalence of infertility was 15.5% (2680/17 275). Among 10 742 women attempting to become pregnant, the prevalence of infertility was 25.0% (2680/10 742), which increased with age in the second population. Among women who failed to achieve pregnancy in the last 12 months, 3470 finished our questionnaire about fertility care, and 55.2% (1915/3470) of them had sought medical help. Sociodemographic risk factors for infertility included lower educational level adjusted odds ratio (aOR) 3.4, 95% CI 2.0–5.5 and employment (aOR 2.3, 95% CI 1.9–2.9). Clinical risk factors were irregular menstrual cycle (aOR 1.8, 95% CI 1.2–2.5), light menstrual blood volume (aOR 1.6, 95% CI 1.2–2.0), history of cervicitis (aOR 1.5, 95% CI 1.2–2.0) and endometriosis (aOR 3.1, 95% CI 1.1–9.3), previous stillbirth (aOR 2.1, 95% CI 1.3–3.3) and miscarriage (aOR 2.7, 95% CI 2.1–3.5). In addition, history of operation was a significant risk factor of infertility.
Conclusions
Among couples of reproductive age in China, the prevalence of infertility was 25%, and almost half of the couples experiencing infertility had not sought medical help.
Tweetable
In China, 25% of couples actively attempting to become pregnant suffered infertility.
Tweetable
In China, 25% of couples actively attempting to become pregnant suffered infertility.
A repeating fast radio burst Spitler, L G; Scholz, P; Hessels, J W T ...
Nature (London),
03/2016, Letnik:
531, Številka:
7593
Journal Article
Recenzirano
Odprti dostop
Fast radio bursts are millisecond-duration astronomical radio pulses of unknown physical origin that appear to come from extragalactic distances. Previous follow-up observations have failed to find ...additional bursts at the same dispersion measure (that is, the integrated column density of free electrons between source and telescope) and sky position as the original detections. The apparent non-repeating nature of these bursts has led to the suggestion that they originate in cataclysmic events. Here we report observations of ten additional bursts from the direction of the fast radio burst FRB 121102. These bursts have dispersion measures and sky positions consistent with the original burst. This unambiguously identifies FRB 121102 as repeating and demonstrates that its source survives the energetic events that cause the bursts. Additionally, the bursts from FRB 121102 show a wide range of spectral shapes that appear to be predominantly intrinsic to the source and which vary on timescales of minutes or less. Although there may be multiple physical origins for the population of fast radio bursts, these repeat bursts with high dispersion measure and variable spectra specifically seen from the direction of FRB 121102 support an origin in a young, highly magnetized, extragalactic neutron star.
To characterise activation of the type I interferon (IFN) pathway in patients with systemic lupus erythematosus (SLE), dermatomyositis (DM), polymyositis (PM), rheumatoid arthritis (RA) and systemic ...scleroderma (SSc) and to evaluate the potential to develop a molecular diagnostic tool from the peripheral blood that reflects this activation in disease-affected tissues.
Overexpressed transcripts were identified in the whole blood (WB) of 262 patients with SLE, 44 with DM, 33 with PM, 28 with SSc and 89 with RA and compared with 24 healthy subjects using Affymetrix microarrays. A five gene type I IFN signature was assessed in these subjects to identify subpopulations showing both activation and concordance of the type I IFN pathway in the peripheral blood and disease-affected tissues of each disease and to correlate activation of this pathway in the WB with clinical measurements.
A common set of 36 type I IFN inducible transcripts were identified among the most overexpressed in the WB of all subjects. Significant activation of the type I IFN pathway in subgroups of each of the five diseases studied was observed. Baseline disease activity measurements correlated with a type I IFN gene signature in the WB of subjects with SLE, PM and SSc, as did various serum autoantibody levels in subjects with SLE and DM. This signature was also well correlated between disease-affected tissue and WB in subjects with SLE, DM, PM and SSc.
The results indicate that the type I IFN pathway is activated in patient subsets of five rheumatic diseases and suggest that these subsets may benefit from anti-IFN therapy.
Symmetries play a fundamental role in modern theories of gravity. The strong equivalence principle (SEP) constitutes a collection of gravitational symmetries which are all implemented by general ...relativity. Alternative theories, however, are generally expected to violate some aspects of SEP. We test three aspects of SEP using observed change rates in the orbital period and eccentricity of binary pulsar J1713+0747: (1) the gravitational constant’s constancy as part of locational invariance of gravitation; (2) the universality of free fall (UFF) for strongly self-gravitating bodies; (3) the post-Newtonian parameter ˆα3 in gravitational Lorentz invariance. Based on the pulsar timing result of the combined data set from the North American
Nanohertz Gravitational Observatory and the European Pulsar Timing Array, we find G˙ /G = (−0.1 ± 0.9) × 10−12 yr−1, which is weaker than Solar system limits, but applies for strongly self-gravitating objects. Furthermore, we obtain an improved test for a UFF violation by a strongly self-gravitating mass falling in the gravitational field of our Galaxy, with a limit of |Delta| < 0.002 (95 per cent C.L.). Finally, we derive an improved limit on the self-acceleration of a gravitationally bound rotating body, to a preferred reference frame in the Universe, with −3 × 10−20 < ˆα3 < 4 × 10−20 (95 per cent C.L.). These results are based on direct UFF and ˆα3 tests using pulsar binaries, and they overcome various limitations of previous tests of this kind.
ABSTRACT We report the discovery of two long-term intermittent radio pulsars in the ongoing Pulsar Arecibo L-Band Feed Array survey. Following discovery with the Arecibo Telescope, extended ...observations of these pulsars over several years at Jodrell Bank Observatory have revealed the details of their rotation and radiation properties. PSRs J1910+0517 and J1929+1357 show long-term extreme bimodal intermittency, switching between active (ON) and inactive (OFF) emission states and indicating the presence of a large, hitherto unrecognized underlying population of such objects. For PSR J1929+1357, the initial duty cycle was fON = 0.008, but two years later, this changed quite abruptly to fON = 0.16. This is the first time that a significant evolution in the activity of an intermittent pulsar has been seen, and we show that the spin-down rate of the pulsar is proportional to the activity. The spin-down rate of PSR J1929+1357 is increased by a factor of 1.8 when it is in active mode, similar to the increase seen in the other three known long-term intermittent pulsars. These discoveries increase the number of known pulsars displaying long-term intermittency to five. These five objects display a remarkably narrow range of spin-down power ( ) and accelerating potential above their polar caps. If confirmed by further discoveries, this trend might be important for understanding the physical mechanisms that cause intermittency.
Flavonoids are a group of polyphenolic compounds, diverse in chemical structure and characteristics, found ubiquitously in plants. Until now, more than 9000 different flavonoid compounds were ...described in plants, where they play important biological roles by affecting several developmental processes. There has been increasing interest in the research of flavonoids from dietary sources, due to growing evidence of the versatile health benefits of flavonoids including anti-inflammatory, antioxidant, antiproliferative and anticancer activity, freeradical scavenging capacity, antihypertensive effects, coronary heart disease prevention and anti-human immunodeficiency virus functions. This paper reviews the current advances in flavonoids in food with emphasis on mechanism aspects on the basis of the published literature, which may provide some guidance for researchers in further investigations and for industries in developing practical health agents.
ABSTRACT We report on the discovery and timing observations of 29 distant long-period pulsars found in the ongoing Arecibo L-band Feed Array pulsar survey. Following discovery with the Arecibo ...Telescope, confirmation and timing observations of these pulsars over several years at Jodrell Bank Observatory have yielded high-precision positions and measurements of rotation and radiation properties. We have used multi-frequency data to measure the interstellar scattering properties of some of these pulsars. Most of the pulsars have properties that mirror those of the previously known pulsar population, although four show some notable characteristics. PSRs J1907+0631 and J1925+1720 are young and are associated with supernova remnants or plerionic nebulae: J1907+0631 lies close to the center of SNR G40.5−0.5, while J1925+1720 is coincident with a high-energy Fermi γ-ray source. One pulsar, J1932+1500, is in a surprisingly eccentric, 199 day binary orbit with a companion having a minimum mass of 0.33 M . Several of the sources exhibit timing noise, and two, PSRs J0611+1436 and J1907+0631, have both suffered large glitches, but with very different post-glitch rotation properties. In particular, the rotational period of PSR J0611+1436 will not recover to its pre-glitch value for about 12 years, a far greater recovery timescale than seen following any other large glitches.
AbstractSkirted gravity base foundations and suction caisson foundations are considered as viable alternatives to monopile foundations for offshore wind turbines. While recent work has focused on the ...monotonic moment-rotation response for shallow foundations, the cyclic response and the accumulation of rotation over the life of the turbine must also be addressed. This paper presents cyclic loading tests where approximately 10,000 cycles, with different loading characteristics, were applied to a model shallow foundation (a caisson) in loose sand. On the basis of these tests, a framework for assessing the accumulated angular rotation because of cycling was developed. The settlement and cyclic stiffness response of the caisson were also assessed. It was found, not unexpectedly, that the accumulated settlement of the caisson increased with the number of cycles and cyclic amplitude. It was also found that a cyclic loading regime intermediate between one-way and full two-way cycling produced the largest rotations. The cyclic stiffness was relatively unaffected by the number of cycles. Using an appropriate scaling technique, the proposed framework was used to predict the long-term accumulated angular rotation, for an example, the field-scale monocaisson structure.
Celotno besedilo
Dostopno za:
DOBA, FGGLJ, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Summary
The relationship between mycoplasma and ureaplasma infection and male infertility has been studied widely; however, results remain controversial. This meta‐analysis investigated the ...association between genital ureaplasmas (Ureaplasma urealyticum, Ureaplasma parvum) and mycoplasmas (Mycoplasma hominis, Mycoplasma genitalium), and risk of male infertility. Differences in prevalence of ureaplasma and mycoplasma infection between China and the rest of the world were also compared. Study data were collected from PubMed, Embase and the China National Knowledge Infrastructure. Summary odds ratio (OR) with 95% confidence interval (CI) was applied to assess the relationship. Heterogeneity testing and publication bias testing were also performed. A total of 14 studies were used: five case–control studies with 611 infertile cases and 506 controls featuring U. urealyticum infection, and nine case–control studies with 2410 cases and 1223 controls concerning M. hominis infection. Two other infection (U. parvum and M. genitalium) were featured in five and three studies, respectively. The meta‐analysis results indicated that U. parvum and M. genitalium are not associated with male infertility. However, a significant relationship existed between U. urealyticum and M. hominis and male infertility. Comparing the global average with China, a significantly higher positive rate of U. urealyticum, but a significantly lower positive rate of M. hominis, was observed in both the infertile and control groups in China.
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