Carbon productivity and economic growth patterns in China

This article discusses the changes in carbon productivity and economic growth patterns in China. We calculated carbon productivity using panel data from BRICS and G7 countries between 2001 and 2019 and developed a methodology to estimate economic growth patterns by combining carbon productivity and economic growth. As the world’s top carbon emitter, China can combat global climate change by increasing carbon productivity. We show that (i) China has a high growth rate of carbon productivity; however, the carbon productivity level only accounts for about 20% of developed countries. (ii) When determining economic growth patterns from a low-carbon perspective, China has transitioned from high-carbon type II to low-carbon type III. However, low-carbon economic growth is common in developed countries, and (iii) it can improve carbon productivity by reducing energy-averaged carbon emission factors. It assists the government in determining how to implement low-carbon economic development policies by examining economic growth from a low-carbon perspectiv

An Abnormal Network Traffic Detection Algorithm Based on Big Data Analysis

Anomaly network detection is a very important way to analyze and detect malicious behavior in network. How to effectively detect anomaly network flow under the pressure of big data is a very important area, which has attracted more and more researchers’ attention. In this paper, we propose a new model based on big data analysis, which can avoid the influence brought by adjustment of network traffic distribution, increase detection accuracy and reduce the false negative rate. Simulation results reveal that, compared with k-means, decision tree and random forest algorithms, the proposed model has a much better performance, which can achieve a detection rate of 95.4% on normal data, 98.6% on DoS attack, 93.9% on Probe attack, 56.1% on U2R attack, and 77.2% on R2L attack

Strong Interplay between Stripe Spin Fluctuations, Nematicity and Superconductivity in FeSe

Elucidating the microscopic origin of nematic order in iron-based superconducting materials is important because the interactions that drive nematic order may also mediate the Cooper pairing. Nematic order breaks fourfold rotational symmetry in the iron plane, which is believed to be driven by either orbital or spin degrees of freedom. However, as the nematic phase often develops at a temperature just above or coincides with a stripe magnetic phase transition, experimentally determining the dominant driving force of nematic order is difficult. Here, we use neutron scattering to study structurally the simplest iron-based superconductor FeSe, which displays a nematic (orthorhombic) phase transition at $T_s=90$ K, but does not order antiferromagnetically. Our data reveal substantial stripe spin fluctuations, which are coupled with orthorhombicity and are enhanced abruptly on cooling to below $T_s$. Moreover, a sharp spin resonance develops in the superconducting state, whose energy (~4 meV) is consistent with an electron boson coupling mode revealed by scanning tunneling spectroscopy, thereby suggesting a spin fluctuation-mediated sign-changing pairing symmetry. By normalizing the dynamic susceptibility into absolute units, we show that the magnetic spectral weight in FeSe is comparable to that of the iron arsenides. Our findings support recent theoretical proposals that both nematicity and superconductivity are driven by spin fluctuations.Comment: 19 pages, 8 figure

Investigation and analysis of bacteria contamination of edible raw meat and related products in catering of Shanghai in 2019

Objective To detect microbial contamination status of edible raw meat products in catering enterprises of Shanghai and to provide reference for food safety and supervision. Methods According to the national standards a total of 198 batches of edible raw meat products and related products from catering enterprises in Shanghai in 2019 were tested for hygienic indicator organisms and common foodborne pathogenic bacteria. SPSS 16.0 software was used to analyze the test result. Results Judging from the hygienic indicator organisms, 2.06% (2/97) of edible raw meat products, raw and supplementary materials had aerobic plate count ≥ 100 000 CFU/g, 5.15% (5/97) of them had coliforms more than 100 CFU/g, and the detection rate of Escherichia coli was 2.06% (2/97), among which the detection rate of raw beef samples was 11.11% (2/18) and the quantitative value was all 10 CFU/g. In terms of the contact surface samples of ready-to-eat foods, the detection rate of coliform was 12.87% (13/101), among which the positive rate of processing tools and utensils was 20.83% (10/48), higher than the tableware samples 5.66% (3/53) (χ2=12.678, P<0.05). According to the detection of foodborne pathogenic bacteria, the detection rates of Salmonella in raw beef and finished products were 5.56% (1/18) respectively and no foodborne pathogens were detected in the remaining samples. Conclusion According to the result of this survey, the detection of the hygienic indicator organisms and Salmonella of edible raw meat products and the raw materials from catering in Shanghai in 2019 was worthy of attention, and the supervison agency should attach importance to the hygienic supervision of the processing tools and utensils in direct contact with ready-to-eat foods

Frustrated magnetic interactions and quenched spin fluctuations in CrAs

The discovery of pressure-induced superconductivity in helimagnets (CrAs, MnP) has attracted considerable interest in understanding the relationship between complex magnetism and unconventional superconductivity. However, the nature of the magnetism and magnetic interactions that drive the unusual double-helical magnetic order in these materials remains unclear. Here, we report neutron scattering measurements of magnetic excitations in CrAs single crystals at ambient pressure. Our experiments reveal well defined spin wave excitations up to about 150 meV with a pseudogap below 7 meV, which can be effectively described by the Heisenberg model with nearest neighbor exchange interactions. Most surprisingly, the spin excitations are largely quenched above the Neel temperature, in contrast to cuprates and iron pnictides where the spectral weight is mostly preserved in the paramagnetic state. Our results suggest that the helimagnetic order is driven by strongly frustrated exchange interactions, and that CrAs is at the verge of itinerant and correlation-induced localized states, which is therefore highly pressure-tunable and favorable for superconductivity.Comment: 6 pages, 4 figure

Transition from sign-reversed to sign-preserved Cooper-pairing symmetry in sulfur-doped iron selenide superconductors

An essential step toward elucidating the mechanism of superconductivity is to determine the sign/phase of superconducting order parameter, as it is closely related to the pairing interaction. In conventional superconductors, the electron-phonon interaction induces attraction between electrons near the Fermi energy and results in a sign-preserved s-wave pairing. For high-temperature superconductors, including cuprates and iron-based superconductors, prevalent weak coupling theories suggest that the electron pairing is mediated by spin fluctuations which lead to repulsive interactions, and therefore that a sign-reversed pairing with an s+-or d-wave symmetry is favored. Here, by using magnetic neutron scattering, a phase sensitive probe of superconducting gap, we report the observation of a transition from the sign-reversed to sign-preserved Cooper-pairing symmetry with insignificant changes in Tc in the S-doped iron selenide superconductors KxFe2-y(Se1-zSz)2. We show that a rather sharp magnetic resonant mode well below the superconducting gap (2delta) in the undoped sample (z = 0) is replaced by a broad hump structure above 2delta under 50% S doping. These results cannot be readily explained by simple spin fluctuation-exchange pairing theories and, therefore, multiple pairing channels are required to describe superconductivity in this system. Our findings may also yield a simple explanation for the sometimes contradictory data on the sign of the superconducting order parameter in iron-based materials.Comment: 11 pages, 4 figures, Supplemental Materials available upon reques

ARGO-YBJ detector simulation using GEANT4

'G4argo', a GEANT4-based simulation package for the ARGO-YBJ detector, is described in this paper. G4argo incorporates in the simulation the true RPC time resolution and another 0.5 ns time uncertainty which is introduced from the offline calibration of TDC. In addition, the correct RPC geometry and the true materials for the ARGO-YBJ experimental hall are implemented. As a result, G4argo simulation shows a very good agreement with real data

Salvage Liver Transplantation Is a Reasonable Option for Selected Patients Who Have Recurrent Hepatocellular Carcinoma after Liver Resection

Background: Salvage liver transplantation (SLT) has been reported as being feasible for patients who develop recurrent hepatocellular carcinoma (HCC) after primary liver resection, but this finding remains controversial. We retrospectively studied the clinical characteristics of SLT recipients and conducted a comparison between SLT recipients and primary liver transplantation (PLT) recipients. Methodology and Principal Findings: A retrospective study examined data from the China Liver Transplant Registry (CLTR) for 6,975 transplants performed from January 1999 to December 2009. A total of 6,087 patients underwent PLT and 888 patients underwent SLT for recurrence. Living donor liver transplantation (LDLT) was performed in 389 patients, while 6,586 patients underwent deceased donor liver transplantation (DDLT). Kaplan-Meier curves were used to compare survival rates. The 1-year, 3-year, and 5-year overall survival of SLT recipients was similar to that of PLT recipients: 73.00%, 51.77%, and 45.84 % vs. 74.49%, 55.10%, and 48.81%, respectively (P = 0.260). The 1-year, 3-year and 5-year disease-free survival of SLT recipients was inferior to that of PLT recipients: 64.79%, 45.57%, and 37.78 % vs. 66.39%, 50.39%, and 43.50%, respectively (P = 0.048). Similar survival results were observed for SLT and PLT within both the LDLT and DDLT recipients. Within the SLT group, the 1-year, 3-year, and 5-year overall survival for LDLT and DDLT recipients was similar: 93.33%, 74.67%, and 74.67 % vs. 80.13%, 62.10%, and 54.18 % (P = 0.281), as was the disease-free survival: 84.85%, 62.85%, an