We have searched for continuous gravitational wave (CGW) signals produced by individually resolvable, circular supermassive black hole binaries (SMBHBs) in the latest European Pulsar Timing Array ...(EPTA) data set, which consists of ultraprecise timing data on 41-ms pulsars. We develop frequentist and Bayesian detection algorithms to search both for monochromatic and frequency-evolving systems. None of the adopted algorithms show evidence for the presence of such a CGW signal, indicating that the data are best described by pulsar and radiometer noise only. Depending on the adopted detection algorithm, the 95 per cent upper limit on the sky-averaged strain amplitude lies in the range ... This limit varies by a factor of five, depending on the assumed source position and the most constraining limit is achieved towards the positions of the most sensitive pulsars in the timing array. The most robust upper limit - obtained via a full Bayesian analysis searching simultaneously over the signal and pulsar noise on the subset of ours six best pulsars -- is ... These limits, the most stringent to date at f < 10...nHz, exclude the presence of sub-centiparsec binaries with chirp mass ... out to a distance of about 25 Mpc, and with ... out to a distance of about 1Gpc (...). We show that state-of-the-art SMBHB population models predict <1 per cent probability of detecting a CGW with the current EPTA data set, consistent with the reported non-detection. We stress, however, that PTA limits on individual CGW have improved by almost an order of magnitude in the last five years. The continuing advances in pulsar timing data acquisition and analysis techniques will allow for strong astrophysical constraints on the population of nearby SMBHBs in the coming years. (ProQuest: ... denotes formulae/symbols omitted.)
ANITA's fourth long-duration balloon flight in 2016 detected 29 cosmic-ray (CR)-like events on a background of 0.37_{-0.17}^{+0.27} anthropogenic events. CRs are mainly seen in reflection off the ...Antarctic ice sheets, creating a phase-inverted waveform polarity. However, four of the below-horizon CR-like events show anomalous noninverted polarity, a p=5.3×10^{-4} chance if due to background. All anomalous events are from locations near the horizon; ANITA-IV observed no steeply upcoming anomalous events similar to the two such events seen in prior flights.
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Using data from four field investigations between 2003 and 2009 along the Yellow River mainstream, we examined the transport features and seasonal variations of organic carbon, with a focus on ...contrasting the impacts of human activities with those of natural processes. Particulate organic carbon (POC) in the Yellow River originated mainly from the Loess Plateau, and thus the POC content in suspended sediments was much lower than in the world's other large rivers. Owing to both natural and human influences, dissolved organic carbon (DOC) has only a weak correlation with discharge. DOC varied as a result of human activities such as agricultural irrigation and pollution in the whole basin except for the upstream Qinghai-Tibetan Plateau. Our study also suggested that while reservoirs are a POC sink over short periods, a long-term POC storage flux cannot be easily estimated as discharge and sediment regulations have completely changed the relationship between the fluxes of water, sediments, and rainfall. However, this carbon sink can be obtained reliably through high-frequency sampling over long time periods. In addition, the annual water and sediment regulation (WSR) scheme has imposed an extremely severe human disturbance on the transport pattern of river organic carbon. Our study demonstrated for the first time that in a WSR event of less than 20 days, large proportions of the annual DOC (35%) and POC (56%) fluxes of the Yellow River were transported to the estuarine and coastal zone, potentially influencing estuarine and coastal geochemistry and ecosystems profoundly.
Three CuO/CeO2 catalyst with different morphologies of ceria, namely nanospheres, nanorods and nanocubes, were synthesized and used to catalyze the water-gas shift (WGS) reaction. The reactivity ...tests showed that the Cu supported on the ceria nanospheres exhibited both the highest activity and superior stability when compared with the nanocube and nanorod ceria catalysts. Operando X-ray diffraction (XRD), X-ray absorption fine structure (XAFS) and diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS) methods were used to characterize these catalysts in their working state. High resolution electron microscopy (HRTEM, STEM) was used to look at the local atomic structure and nano-scale morphology. Our results show that the morphology of the ceria support, which can involve different crystal faces and concentrations of defects and imperfections, has a critical impact on the catalytic properties and influences: (1) the dispersion of CuO in the as-synthesized catalyst; (2) the particle size of metallic Cu upon reduction during the WGS reaction, (3) the stability of the metallic Cu upon variations of temperature, and (4) the dissociation of water on the ceria support. The nanosphere ceria catalyst showed an excellent water dissociation capability, the best dispersion of Cu and a strong Cu-Ce interaction, therefore delivering the best performance among the three WGS catalysts. The metallic Cu, which is the active species during the WGS reaction, was more stabilized on the nanospheres than on the nanorods and nanocubes and thus led to a better stability of the nanosphere catalyst than the other two architectures. Each catalyst exhibited a distinctive line-shape in the 800-1600 cm(-1) region of the DRIFTS spectra, pointing to the existence of different types of carbonate or carboxylate species as surface intermediates for the WGS.
MicroRNAs have been shown to play an important role in normal hematopoisis and leukemogenesis. Here, we report function and mechanisms of miR-181 family in myeloid differentiation and acute myeloid ...leukemia (AML). The aberrant overexpression of all the miR-181 family members (miR-181a/b/c/d) was detected in French-American-British M1, M2 and M3 subtypes of adult AML patients. By conducting gain- and loss-of-function experiments, we demonstrated that miR-181a inhibits granulocytic and macrophage-like differentiation of HL-60 cells and CD34+ hematopoietic stem/progenitor cells (HSPCs) by directly targeting and downregulating the expression of PRKCD (which then affected the PRKCD-P38-C/EBPα pathway), CTDSPL (which then affected the phosphorylation of retinoblastoma protein) and CAMKK1. The three genes were also demonstrated to be the targets of miR-181b, miR-181c and miR-181d, respectively. Significantly decreases in the expression levels of the target proteins were detected in AML patients. Inhibition of the expression of miR-181 family members owing to Lenti-miRZip-181a infection in bone marrow blasts of AML patients increased target protein expression levels and partially reversed myeloid differentiation blockage. In the mice implanted with AML CD34+ HSPCs, expression inhibition of the miR-181 family by Lenti-miRZip-181a injection improved myeloid differentiation, inhibited engraftment and infiltration of the leukemic CD34+ cells into the bone marrow and spleen, and released leukemic symptoms. In conclusion, our findings revealed new mechanism of miR-181 family in normal hematopoiesis and AML development, and suggested that expression inhibition of the miR-181 family could provide a new strategy for AML therapy.
In this paper, we examine the dynamic nature of the resilience process as an interaction between individuals and their larger socio-ecological context. We introduce a novel, multi-systems model of ...resilience that addresses limitations within existing models, clarifies ambiguity brought on by heterogeneous definitions of resilience, and recognizes resilience as a process across the lifespan. This model includes intra-individual, interpersonal, and socio-ecological variables, and highlights the interactive process of resilience that is dynamic and multi-dimensional in nature.
•Resilience is an interactive process between individuals and the larger community.•Research suffers from ambiguous definitions and variability in measuring outcomes.•A multi-system model is proposed to address limitations in resilience research.•Proposed systems are intra-individual, interpersonal, and socio-ecological.
Context.
No robust detection of prompt electromagnetic counterparts to fast radio bursts (FRBs) has yet been obtained, in spite of several multi-wavelength searches having been carried out so far. ...Specifically, X/
γ
-rays counterparts are predicted by some models.
Aims.
We aim to search for prompt
γ
-ray counterparts in the Insight-Hard X-ray Modulation Telescope (Insight-HXMT) data, taking advantage of the unique combination of the large effective area in the keV–MeV energy range, and of sub-ms time resolution.
Methods.
We selected 39 FRBs that were promptly visible from the High-Energy (HE) instrument aboard Insight-HXMT. After calculating the expected arrival times at the location of the spacecraft, we searched for a significant excess in both individual and cumulative time profiles over a wide range of time resolutions, from several seconds down to sub-ms scales. Using the dispersion measures in excess of the Galactic terms, we estimated the upper limits on the redshifts.
Results.
No convincing signal was found, and for each FRB we constrained the
γ
-ray isotropic-equivalent luminosity and the released energy as a function of emission timescale. For the nearest FRB source, the periodic repeater FRB 180916.J0158+65, we find
L
γ
, iso
< 5.5 × 10
47
erg s
−1
over 1 s, whereas
L
γ
, iso
< 10
49
− 10
51
erg s
−1
for the bulk of FRBs. The same values scale up by a factor of ∼100 for a ms-long emission.
Conclusions.
Even on a timescale comparable with that of the radio pulse itself, no keV–MeV emission is observed. A systematic association with either long or short GRBs is ruled out with high confidence, except for sub-luminous events, as is the case for the core-collapse of massive stars (long) or binary neutron star mergers (short) viewed off axis. Only giant flares from extragalactic magnetars at least ten times more energetic than Galactic siblings are ruled out for the nearest FRB.
Despite the importance of immunological memory for protective immunity against viral infection, whether H7N9-specific antibodies and memory T-cell responses remain detectable years after the original ...infection is unknown.
A cross-sectional study was conducted to investigate the immune memory responses of H7N9 patients who contracted the disease and survived during the 2013–2016 epidemics in China. Sustainability of antibodies and T-cell memory to H7N9 virus were examined. Healthy individuals receiving routine medical examinations in a physical examination centre were recruited as control.
A total of 75 survivors were enrolled and classified into four groups based on the time elapsed from illness onset to specimen collection: 3 months (n = 14), 14 months (n = 14), 26 months (n = 28) and 36 months (n = 19). Approximately 36 months after infection, the geometric mean titres of virus-specific antibodies were significantly lower than titres in patients 3 months after infection, but 16 of 19 (84.2%) survivors in the 36-month interval had microneutralization (MN) titres ≥40. Despite the overall declining trend, the percentages of virus-specific cytokine-secreting memory CD4+ and CD8+ T cells remained higher in survivors at nearly all time-points in comparison with control individuals. Linear regression analysis showed that severe disease (mean titre ratio 2.77, 95% CI 1.17–6.49) was associated with higher haemagglutination inhibition (HI) titre and female sex for both HI (1.92, 1.02–3.57) and MN (3.33, 1.26–9.09) antibody, whereas female sex (mean percentage ratio 1.69, 95% CI 1.08–2.63), underlying medical conditions (1.94, 95% CI 1.09–3.46) and lack of antiviral therapy (2.08, 95% CI 1.04–4.17) were predictors for higher T-cell responses.
Survivors of H7N9 virus infection produced long-term antibodies and memory T-cell responses. Our findings warrant further serological investigation in general and high-risk populations and have important implications for vaccine design and development.
• A hydroponic experiment was conducted to investigate the effect of phosphorus (P) nutrition and iron plaque on root surfaces on arsenate uptake by, and translocation within, the seedlings of three ...cultivars of rice (Oryza sativa). • Supply of 0.5 mg As l-1 had no significant effects on dry weights of shoots or roots, but resulted in elevated concentrations of As in tissues, particularly in roots Rice roots appeared reddish after 24 h in -P solution (without P), indicating the formation of iron plaque. • Arsenic concentrations in iron plaque (determined in dithionite-citrate-bicarbonate (DCB)-extracts) were significantly higher in -P plants (up to 1180 mg kg-1 in cultivar CDR22) than in +P plants. Concentrations of arsenic in shoots were significantly lower in -P plants than in +P plants. This indicates that iron plaque might sequestrate As, and consequently reduce the translocation of arsenic from roots to shoots. • Values for the total uptake of As show that As in -P rice plants was mainly concentrated in the DCB-extracts or on the surface of rice roots, whereas most arsenic in +P plants was accumulated in the roots. Arsenic significantly decreased the concentrations of iron (Fe) in roots and shoots (P < 0.001) and slightly reduced P concentrations in shoots, except for the -P cultivar CDR22.
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