Effects of Warming and Nitrogen Addition on Soil Enzyme Activities

Due to the intensification of human activities, global warming and increased atmospheric nitrogen deposition have become important driving factors of global change. In order to understand the effects of long-term warming and nitrogen application on soil physical and chemical properties and enzyme activities, the effects of warming and nitrogen application on grassland soil enzyme activities were measured. The aim was to reveal the response of enzyme activity in an Inner Mongolian desert steppe to long-term warming and nitrogen addition. The results were as follows. In 2018, nitrogen fertilization significantly increased soil dehydrogenase activity, and soil depth significantly affected soil urease, β-Glucosidase, phosphatase and dehydrogenase activities. In 2019, the four soil enzyme activities only showed significant differences at different soil depths, while the effects of warming, nitrogen addition and their interactions on soil enzyme activities were not significant. In general, the enzyme activities of desert grassland soil were not affected by warming, while nitrogen addition had a greater impact on the soil enzyme activities. However, large difference in soil moisture between the two years of the experiment was also a key factor leading to large fluctuations between the two years, which indicated that in the semi-arid desert grassland, the change of soil nutrient characteristics is also affected by water content

Cultural differences in neurocognitive mechanisms underlying believing

Believing as a fundamental mental process influences other cognitive/affective processes and behavior. However, it is unclear whether believing engages distinct neurocognitive mechanisms in people with different cultural experiences. We addressed this issue by scanning Chinese and Danish adults using functional MRI during believing judgments on personality traits of oneself and a celebrity. Drift diffusion model analyses of behavioral performances revealed that speed/quality of information acquisition varied between believing judgments on positive and negative personality traits in Chinese but not in Danes. Chinese adopted a more conservative strategy of decision-making during celebrity- than self-believing judgments whereas an opposite pattern was observed in Danes. Non-decisional processes were longer for celebrity- than for self-believing in Danes but not in Chinese. Believing judgments activated the medial prefrontal cortex (mPFC) in both cultural groups but elicited stronger left anterior insular and ventral frontal activations in Chinese. Greater mPFC activity in Chinese was associated with longer duration of non-decision processes during believing-judgments, which predicted slower retrieval of self-related information in a memory test. Greater mPFC activity in Danes, however, was associated with a less degree of adopting a conservative strategy during believing judgments, which predicted faster retrieval of self-related information. Our findings highlight different neurocognitive processes engaged in believing between individuals from East Asian and Western cultures

Study on flow and temperature drop behavior of six-stream tundish with less-flow casting

In this paper, numerical simulation method was used to study the influence of closing different nozzles on the flow state and temperature distribution of molten steel in the six-stream tundish, which provides a theoretical basis for ensuring the temperature uniformity of molten steel in the tundish and the subsequent stable continuous casting production during the less-flow casting. The results show that: (a) In the case of closing one nozzle, when the No. 3 nozzle is closed, the overall temperature is relatively uniform. (b) In the case of closing two nozzles, when the No. 2 and No. 3 nozzles are closed, the overall temperature is more uniform

Study on cleanliness of interstitial-free (IF) steel continuous casting slab

By means of metallographic observation, scanning electron microscopy and electron probe micro analysis, the quantity, particle size, distribution, morphology and composition of inclusions in the slab were discussed in detail. Which can provide a reference for the process optimization of IF steel and the production of pure steel slabs. The results show that the content of C, N and O in the IF steel continuous casting slab produced by this plant is controlled at about 20 ppm, and the content of P and S is lower and the steel is relatively pure. Most of the inclusions are below 2 μm. Most of the inclusions are pure Al2O3, a small part contains a small amount of microscopic MnS

A unique distant submillimeter galaxy with an X-ray-obscured radio-luminous active galactic nucleus

We present a multiwavelength study of an atypical submillimeter galaxy in the GOODS-North field, with the aim to understand its physical properties of stellar and dust emission, as well as the central AGN activity. Although it is shown that the source is likely an extremely dusty galaxy at high redshift, its exact position of submillimeter emission is unknown. With the new NOEMA interferometric imaging, we confirm that the source is a unique dusty galaxy. It has no obvious counterpart in the optical and even NIR images observed with HST at lambda~<1.4um. Photometric-redshift analyses from both stellar and dust SED suggest it to likely be at z~>4, though a lower redshift at z~>3.1 cannot be fully ruled out (at 90% confidence interval). Explaining its unusual optical-to-NIR properties requires an old stellar population (~0.67 Gyr), coexisting with a very dusty ongoing starburst component. The latter is contributing to the FIR emission, with its rest-frame UV and optical light being largely obscured along our line of sight. If the observed fluxes at the rest-frame optical/NIR wavelengths were mainly contributed by old stars, a total stellar mass of ~3.5x10^11Msun would be obtained. An X-ray spectral analysis suggests that this galaxy harbors a heavily obscured AGN with N_H=3.3x10^23 cm^-2 and an intrinsic 2-10 keV luminosity of L_X~2.6x10^44 erg/s, which places this object among distant type 2 quasars. The radio emission of the source is extremely bright, which is an order of magnitude higher than the star-formation-powered emission, making it one of the most distant radio-luminous dusty galaxies. The combined characteristics of the galaxy suggest that the source appears to have been caught in a rare but critical transition stage in the evolution of submillimeter galaxies, where we are witnessing the birth of a young AGN and possibly the earliest stage of its jet formation and feedback.Comment: 13 pages in printer format, 10 figures, 1 table, accepted for publication in the A&

Momentum Distribution of Near-Zero-Energy Photoelectrons in the Strong-Field Tunneling Ionization in the Long Wavelength Limit

We investigate the ionization dynamics of Argon atoms irradiated by an ultrashort intense laser of a wavelength up to 3100 nm, addressing the momentum distribution of the photoelectrons with near-zero-energy. We find a surprising accumulation in the momentum distribution corresponding to meV energy and a \textquotedblleft V"-like structure at the slightly larger transverse momenta. Semiclassical simulations indicate the crucial role of the Coulomb attraction between the escaping electron and the remaining ion at extremely large distance. Tracing back classical trajectories, we find the tunneling electrons born in a certain window of the field phase and transverse velocity are responsible for the striking accumulation. Our theoretical results are consistent with recent meV-resolved high-precision measurements.Comment: 5 pages, 4 figure