The extended gamma-ray source MGRO J1908+06, discovered by the Milagro air shower detector in 2007, has been observed for ~4 years by the ARGO-YBJ experiment at TeV energies, with a statistical ...significance of 6.2 standard deviations. The peak of the signal is found at a position consistent with the pulsar PSR J1907+0602. Parameterizing the source shape with a two-dimensional Gauss function, we estimate an extension of sigma sub(ext) = 0.degrees 49 + or - 0.degrees 22, which is consistent with a previous measurement by the Cherenkov Array H.E.S.S. The observed energy spectrum is dN/dE = 6.1 + or - 1.4 x 10 super(-13) (E/4 TeV) super(-2.54+ or -0.36) photons cm super(-2) s super(-1) TeV super(-1), in the energy range of ~1-20 TeV. The measured gamma-ray flux is consistent with the results of the Milagro detector, but is ~2-3 times larger than the flux previously derived by H.E.S.S. at energies of a few TeV. The continuity of the Milagro and ARGO-YBJ observations and the stable excess rate observed by ARGO-YBJ and recorded in four years of data support the identification of MGRO J1908+06 as the steady powerful TeV pulsar wind nebula of PSR J1907+0602, with an integrated luminosity over 1 TeV ~ 1.8 times the luminosity of the Crab Nebula.
Recently, the LHAASO Collaboration published the detection of 12 ultrahigh-energy γ-ray sources above 100 TeV, with the highest energy photon reaching 1.4 PeV. The first detection of PeV γ rays from ...astrophysical sources may provide a very sensitive probe of the effect of the Lorentz invariance violation (LIV), which results in decay of high-energy γ rays in the superluminal scenario and hence a sharp cutoff of the energy spectrum. Two highest energy sources are studied in this work. No signature of the existence of the LIV is found in their energy spectra, and the lower limits on the LIV energy scale are derived. Our results show that the first-order LIV energy scale should be higher than about 10^{5} times the Planck scale M_{Pl} and that the second-order LIV scale is >10^{-3}M_{Pl}. Both limits improve by at least one order of magnitude the previous results.
To investigate the drug-resistant gene characteristics and core genome characteristics of carbapenem-resistant
(CR-ECL) in rural residents of Weifang City, Shandong Province.
Fecal samples were ...collected from rural community residents in Weifang City, Shandong Province in 2017. Drug-resistant strains were screened using a carbapenem-resistant enterobacter chromogenic medium. CR-ECL positive strains were acquired via Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry(MALDI-TOFMS) analysis. The antibiotic resistance phenotype of CR-ECL was determined using a microbroth dilution assay. Whole genome sequencing (WGS) and analysis were conducted, along with an examination of the immediate vicinity of the
gene and phylogenetic analysis of the strains.
A total of 628 fecal samples were collected and tested, of which 6 were CR-ECL positive (detection rate 0.96%), all exhibiting multiple drug resistance (MDR) phenotypes. Six CR-ECL strains had four MLST genotypes (ST), all of which carried mul
Although VEGF-B was discovered as a VEGF-A homolog a long time ago, the angiogenic effect of VEGF-B remains poorly understood with limited and diverse findings from different groups. Notwithstanding, ...drugs that inhibit VEGF-B together with other VEGF family members are being used to treat patients with various neovascular diseases. It is therefore critical to have a better understanding of the angiogenic effect of VEGF-B and the underlying mechanisms. Using comprehensive in vitro and in vivo methods and models, we reveal here for the first time an unexpected and surprising function of VEGF-B as an endogenous inhibitor of angiogenesis by inhibiting the FGF2/FGFR1 pathway when the latter is abundantly expressed. Mechanistically, we unveil that VEGF-B binds to FGFR1, induces FGFR1/VEGFR1 complex formation, and suppresses FGF2-induced Erk activation, and inhibits FGF2-driven angiogenesis and tumor growth. Our work uncovers a previously unrecognized novel function of VEGF-B in tethering the FGF2/FGFR1 pathway. Given the anti-angiogenic nature of VEGF-B under conditions of high FGF2/FGFR1 levels, caution is warranted when modulating VEGF-B activity to treat neovascular diseases.
A large high-altitude air shower observatory is to be built at Yang-Ba-Jing, Tibet, China. One of its main purposes is to survey the northern sky for very-high-energy (above 100GeV) gamma ray sources ...via its ground-based water Cherenkov detector array. To gain full knowledge of water Cherenkov technique in detecting air showers, a prototype water Cherenkov detector is built at the Institute of High Energy Physics, Beijing. The performance of the prototype water Cherenkov detector is studied by measuring its response to cosmic muons. The results are compared with those from a full Monte Carlo simulation to provide a series of information regarding the prototype detector in guiding electronics design and detector optimization.
We report the observation of TeV gamma -rays from the Cygnus region using the ARGO-YBJ data collected from 2007 November to 2011 August. Several TeV sources are located in this region including the ...two bright extended MGRO J2019+37 and MGRO J2031+41. According to the Milagro data set, at 20 TeV MGRO J2019+37 is the most significant source apart from the Crab Nebula. No signal from MGRO J2019+37 is detected by the ARGO-YBJ experiment, and the derived flux upper limits at the 90% confidence level for all the events above 600 GeV with medium energy of 3 TeV are lower than the Milagro flux, implying that the source might be variable and hard to be identified as a pulsar wind nebula. The only statistically significant (6.4 standard deviations) gamma -ray signal is found from MGRO J2031+41, with a flux consistent with the measurement by Milagro.
The 0.2Li
2
ZrO
3
–0.8MgO (Li
2
Mg
4
ZrO
7
) ceramics were prepared by conventional solid-state reaction method. The effects of lithium fluoride (LiF) addition on the microstructure, sintering ...temperature and microwave dielectric properties of Li
2
Mg
4
ZrO
7
ceramics were investigated. The experimental results demonstrated a typical single phase existed in Li
2
Mg
4
ZrO
7
–LiF ceramics, in which LiF was proved to be an effective sintering aid for the Li
2
Mg
4
ZrO
7
ceramic. LiF obviously lowed the optimum sintering temperature of Li
2
Mg
4
ZrO
7
ceramic from 1500 to 1050 °C and improved the sintering ability of the matrix. In this paper, the microwave dielectric properties were strongly dependent on the amount of LiF additions and the sintering temperature. Optimum microwave dielectric properties (
ε
r
= 12.95,
Q
·
f
= 180,011 GHz and
τ
f
=− 23.51 ppm/°C) were obtained in Li
2
Mg
4
ZrO
7
-4 wt% LiF ceramics sintered at 1050 °C.
To accomplish the rapid start-up and stable operation of biogas digesters, an efficient inoculum is required. To obtain such an inoculum for food waste anaerobic digestion, we domesticated dairy ...manure anaerobic digestion residue by adding food waste every day. After 36 days, the pH and biogas yield stabilized signifying the completion of domestication. During domestication, the microbial communities in the inocula were investigated by constructing 16S rDNA clone libraries. We evaluated the effect of the domesticated inoculum by testing batch food waste anaerobic digestion with a non-domesticated inoculum as a control. The pH and methane yield of the digestion systems were determined as measurement indices. Domestication changed the composition and proportion of bacteria and archaea in the inocula. Of the bacteria, Clostridia (49.3%), Bacteroidales (19.5%), and Anaerolinaceae (8.1%) species were dominant in the seed sludge; Anaerolinaceae (49.0%), Clostridia (28.4%), and Bacteroidales (9.1%), in domestication sludge. Methanosaeta was the dominant genus in both of the seed (94.3%) and domestication (74.3%) sludge. However, the diversity of methanogenic archaea was higher in the domestication than in seed sludge. Methanoculleus, which was absent from the seed sludge, appeared in the domestication sludge (21.7%). When the domesticated inoculum was used, the digestion system worked stably (organic loading rate: 20 gVS/L; methane yield: 292.2 ± 9.8 mL/gVS; VS = volatile solids), whereas the digestion system inoculated with seed sludge failed to generate biogas. The results indicate that inoculum domestication ensures efficient and stable anaerobic digestion by enriching the methanogenic strains.
PDF
