Unraveling the unusually high electrical conductivity of the delafossite metal PdCoO2_2

The prototypical delafossite metal PdCoO$_2$ has been the subject of intense interest for hosting exotic transport properties. Using first-principles transport calculations and theoretical modeling, we reveal that the high electrical conductivity of PdCoO$_2$ at room temperature originates from the contributions of both high Fermi velocities, enabled by Pd $4d_{z^2}-5s$ hybridization, and exceptionally weak electron-phonon coupling, which leads to a coupling strength ($\lambda=0.057$) that is nearly an order of magnitude smaller than those of common metals. The abnormally weak electron-phonon coupling in PdCoO$_2$ results from a low electronic density of states at the Fermi level, as well as the large and strongly facetted Fermi surface with suppressed Umklapp electron-phonon matrix elements. We anticipate that our work will inform the design of unconventional metals with superior transport properties.Comment: 6 pages, 3 figure

Chirality-induced spin splitting in 1D InSeI

Spin-orbit coupling (SOC) in chiral materials can induce chirality-dependent spin splitting, enabling electrical manipulation of spin polarization. Here, we use first-principles calculations to investigate the electronic states of chiral one-dimensional (1D) InSeI, which has two enantiomorphic configurations with left- and right-handedness. We find that opposite spin states exist in the left- and right-handed 1D InSeI with significant spin splitting. Although the spin states at the conduction band minimum (CBM) and valence band maximum (VBM) are both degenerate, a direct-to-indirect bandgap transition occurs when a moderate tensile strain ($\sim$4%) is applied along the 1D chain direction, leading to chirality-dependent and collinear spin-momentum locking at the CBM. These findings indicate that 1D InSeI is a promising material for chiral spintronics.Comment: 7 pages, 3 figure

Structure basis for the unique specificity of medaka enteropeptidase light chain

Thermal stresses concern not renewed type of stresses, that is once having liberated, they cannot accumulate more. The estimation of purely thermoelastic contribution to a lithosphere stress state gives the additional information, allowing to predict the danger connected with such natural factors, as seismic and volcanic activity. Some theoretical thermoelastic problems for the geological environment of a difficult outline with non-uniform thermophysical characteristics are considered. The decision is received on the basis of a numerical finite elements method. Influence of the model fixation, the geometrical factor and boundary conditions on distribution of thermal stresses and dislocation is investigated. Computing experiments have shown, that the size of the maximum thermal stresses reaches 500 bar. The maximum values of vertical dislocation are reached by 90 m, and horizontal — 50 m. Neutral plane position are precisely defined. Термоупругие напряжения относятся к невозобновляемому типу напряжений, то есть, однажды высвободившись, напряжения не могут накапливаться вновь. Расчет термоупругого вклада в напряженное состояние литосферы дает дополнительную информацию, позволяющую оценить опасность, связанную с такими природными явлениями, как сейсмичность и вулканическая активность. Рассмотрено несколько теоретических моделей для геологической среды сложного очертания с неоднородными теплофизическими характеристиками. Решение получено на основе численного метода конечных элементов. Исследовано влияние «закрепления» модели, геометрического фактора, неоднородных граничных условий на распределение термоупругих напряжений и перемещений. Вычислительные эксперименты показали, что величина максимальных термоупругих напряжений достигает 500 б. Максимальные величины вертикальных перемещений не превышают 90 м, горизонтальных — 50 м. Положение нейтральной плоскости определяется точно. На основі методу скінченних елементів отримано детальний розподіл термопружних напружень і переміщень для неоднорідного геологічного середовища. Досліджено взаємний вплив геометрії середовища й неоднорідних граничних умов на розподіл термопружних напружень та переміщень

Characterization and anti-aging activities of polysaccharide from Rana dybowskii Guenther

Introduction:Rana dybowskii Guenther (RDG), as a traditional Chinese medicine, has been shown to have antioxidant effects. However, studies on the anti-aging effect of RDG are still limited.Methods: In this study, we prepared polysaccharides from the skin of RDG (RDGP) by hot water extraction, alcohol precipitation, ion-exchange chromatography and gel chromatography. The proteins were removed using the Sevage method in combination with an enzymatic method. The structural features were analyzed using high-performance gel permeation chromatography, β-elimination reaction and Fourier transform infrared spectra. The anti-aging effect of RDGP was investigated by using D-Gal to establish an aging model in mice, and pathological changes in the hippocampus were observed under a microscope.Results: We obtained the crude polysaccharide DGP from the skin of RDG, with a yield of 61.8%. The free protein was then removed by the Sevage method to obtain DGPI and deproteinated by enzymatic hydrolysis combined with the Sevage method to further remove the bound protein to obtain the high-purity polysaccharide DGPII. Then, DGPIa (1.03 × 105 Da) and DGPIIa (8.42 × 104 Da) were obtained by gel chromatography, monosaccharide composition analysis showed that they were composed of Man, GlcA, GalNAc, Glc, Gal, Fuc with molar ratios of 1: 4.22 : 1.55: 0.18 : 8.05: 0.83 and 0.74 : 1.78: 1: 0.28: 5.37 : 0.36, respectively. The results of the β-elimination reaction indicated the presence of O-glycopeptide bonds in DGPIa. The Morris water maze test indicated that mice treated with DGPIIa exhibited a significantly shorter escape latency and increased time spent in the target quadrant as well as an increase in the number of times they traversed the platform. Pathologic damage to the hippocampus was alleviated in brain tissue stained with hematoxylin-eosin. In addition, DGPIIa enhanced the activities of SOD, CAT, and GSH-Px and inhibited the level of MDA in the serum and brain tissues of aging mice.Discussion: These results suggest that RDGP has potential as a natural antioxidant and provide useful scientific information for anti-aging research

Formation of the synaptonemal complex in a gynogenetic allodiploid hybrid fish

Introduction: The correct pairing and separation of homologous chromosomes during meiosis is crucial to ensure both genetic stability and genetic diversity within species. In allodiploid organisms, synapsis often fails, leading to sterility. However, a gynogenetic allodiploid hybrid clone line (GDH), derived by crossing red crucian carp (Carassius auratus ♀) and common carp (Cyprinus carpio ♂), stably produces diploid eggs. Because the GDH line carries 100 chromosomes with 50 chromosomes from the red crucian carp (RCC; ♀, 2n = 2x = 100) and 50 chromosomes from the common carp (CC; C. carpio L., ♂, 2n = 2x = 100), it is interesting to study the mechanisms of homologous chromosome pairing during meiosis in GDH individuals.Methods: By using fluorescence in situ hybridization (FISH) with a probe specific to the red crucian carp to label homologous chromosomes, we identified the synaptonemal complex via immunofluorescence assay of synaptonemal complex protein 3 (SCP3).Results: FISH results indicated that, during early ovarian development, the GDH oogonium had two sets of chromosomes with only one set from Carassius auratus, leading to the failure formation of normal bivalents and the subsequently blocking of meiosis. This inhibition lasted at least 5 months. After this long period of inhibition, pairs of germ cells fused, doubling the chromosomes such that the oocyte contained two sets of chromosomes from each parent. After chromosome doubling at 10 months old, homologous chromosomes and the synaptonemal complex were identified.Discussion: Causally, meiosis proceeded normally and eventually formed diploid germ cells. These results further clarify the mechanisms by which meiosis proceeds in hybrids

Market Entry Strategy of the Global Corporations on the Markets of China

With the rapid development of social and economic globalization, the process of world economic globalization has become an irreversible trend. In the process of globalization, multinational companies are the most important carriers. However, the choice of market entry strategy is a key issue for the success of multinational corporations. Appropriate entry strategy will have a significant impact on the future management and business performance of enterprises. This will also bring huge convenience and profits to the enterprise. On the other hand, the speed and scope of Chinese economic growth make it unique. As one of the most attractive investment destinations for global investors, almost all the world's automobile manufacturing giants now have factories in China. Volkswagen Group is one of the earliest investors in China and the largest foreign automobile manufacturer, and its entry and development strategy has been very successful. This term paper will analyze which specific mode Volkswagen uses to enter the Chinese market, and analyze the reasons behind this choice in detail.S rychlým rozvojem sociální a ekonomické globalizace se stal proces světové ekonomické globalizace nevratným trendem. V procesu globalizace jsou nadnárodní společnosti nejdůležitějšími dopravci. Volba strategie vstupu na trh je však klíčovým tématem úspěchu nadnárodních společností. Vhodná strategie vstupu bude mít významný dopad na budoucí řízení a obchodní výkonnost podniků. Podniku to také přinese obrovské pohodlí a zisky. Na druhou stranu, rychlost a rozsah čínského ekonomického růstu ho činí jedinečným. Jako jedna z nejatraktivnějších investičních destinací pro globální investory má nyní v Číně téměř všechny světové giganty automobilového průmyslu. Skupina Volkswagen je jedním z prvních investorů v Číně a největším zahraničním výrobcem automobilů a její strategie vstupu a vývoje byla velmi úspěšná. Tato seminární práce bude analyzovat, jaký konkrétní režim Volkswagen používá pro vstup na čínský trh, a podrobně analyzovat důvody této volby

Address forms in Chinese audit opinions

Although forms of address are widely used in textual and other types of disclosure, empirical evidence of their effects is rare. China provides a unique setting in which to test the economic consequences of the forms of address used in audit reports. From 2003 to 2011, about 60% of auditors surveyed addressed their clients by their real names in audit opinions, while the others used honorifics. Based on a sample of Chinese audit opinions, I report the following findings. First, the announcement of an audit opinion that uses the client’s real name elicits a greater market response than the announcement of an opinion featuring an honorific form of address. Second, the effects of real-name forms of address are stronger in firms with weak board governance. Third, the association between audit fees and audit risk factors, such as loss-making, is stronger in firms that are addressed by their real names in audit reports. I conclude from these findings that the forms of address used in audit opinions may reveal private information on audit quality. The results of this study are consistent with the power-solidarity effect described by sociolinguists

The Association between Audit Business Scale Advantage and Audit Quality of Asset Write-downs

This paper examines whether the scale advantage of auditing firms can be used as an alternative indicator of audit quality when the evaluation of audit quality is costly. The adoption of asset impairment recognition in China has brought about a considerable impact on financial reporting of Chinese listing companies in recent years. This new accounting practice provided a special environment, which was subjected to less endogeneity problems than usual, to test the relationship between the scale of auditing business and audit quality. Prior research reported empirical evidence that both market value and firm characteristics are empirically related to write-downs, reflected in the four dimensions return relevance, price relevance, persistence and determinant. Using these four dimensions, we investigated whether audit business scale advantage (ABSA) affect audit quality of asset write-downs. We contribute to the literature with the following findings. First, auditors’ business scale is positively related to return relevance of write-downs. Second, auditors with ABSA not only enhance the relevance between impairments and economic variables but also weaken the relation between impairments and managerial variables; however, the results appear in only a few of the firm-specific variables. Third, results are mixed when we test the ABSA effect on price-relevance and persistence dimensions. Fourth, the ABSA effect is stronger when the complexity of asset write-downs requires some inside information to comprehend the nature of action. Adding to the main finding, we also found the ABSA effect became weaker when we proxy ABSA with raw data of companies’ business scale instead of the top five auditors in business scale. Taken together, our results show that the ABSA effect does exist in auditing of assets write-downs, although with weak evidence. Our results also indicated rational auditor choice based on quality of service in China's audit market. We identified some unique factors from stakeholders’ cooperative structuring actions in China audit market as potential explanations to the market rationality

Regulatory Incentives for Earnings Management through Asset Impairment Reversals in China

While asset impairment reversals are practiced in many jurisdictions, empirical evidence is rare. China provides us with a unique opportunity to examine both the determinants and consequences of impairment reversals resulting from recent developments in standard-setting and its specific performance-based listing requirements. Based on a sample of reversal firms in China, we report the following findings: First, Chinese-listed companies are motivated by regulatory incentives to reverse asset impairments to reduce or avoid the possibility of trading suspension or de-listing. Second, we provide some evidence that the value-relevance of reversal information appears to be negatively affected by the regulatory-motivated earnings management. Third, favorable internal and external monitoring mechanisms play a role in constraining this type of earnings management. Taken together, we conclude that while the intention of granting reversal discretion is for managers to reveal private value recovery information, our findings suggest that a seemingly improved accounting standard does not necessarily lead to its intended consequence in financial reporting