The landlocked and fragile countries’ ability to create a sustainable path to economic growth and poverty reduction is inextricably linked to their export diversification potential, itself related to their connectivity within themselves, in the region, and other external markets. Mali, Chad, and Niger are first challenged by their geography—their landlocked nature with their vast and thinly populated space serves to isolate the most vulnerable communities from external and internal markets. Adding to these geographic disadvantages non-landlocked is incentive environment—defined by high and variable customs common external tariff regimes resulting from multiple overlapping regional trade arrangements—places a wedge between domestic and international prices, provides a disincentive to exports in favor of non-tradable and domestic-oriented sectors. By bringing greater coherence and convergence between the many common external tariff regimes in operation and the rationalization of their structures, and improving connectivity within and between markets, Mali, Chad, Niger, and Guinea can better promote the reallocation of resources toward tradable goods and services, putting the countries on a path toward greater economic inclusion and sustainable growth.

Flash flood is one of the major natural hazards in China. It seriously threatens the lives of people and property in mountainous areas. Various methods have been developed for flash flood study, but most of them focused on the past few decades. As one of the effective methods of historical flash flood events reconstruction, dendrogeomorphology has been used worldwide. It can provide hazard information with long temporal scale and high temporal resolution, sometimes at the seasonal level. By comparing tree ring width and other growth characteristics between disturbed and undisturbed trees, growth disturbance signals can be found in the disturbed trees. Using the growth disturbance in tree rings, flash flood events can be dated, and then the frequency, size, and spatial distribution characteristics of flash floods that have no or little documentary records can be reconstructed. The discharge of flash flood can be reconstructed quantitatively according to the height of scars or by using hydraulic models. With the development of dendrogeomorphology, research tends to probe into the meteorological driving mechanism of flash floods and the pattern of flash floods on a larger spatial scale. In the practical application of dendrogeomorphology, more instrumental data and historical records are applied in the studies. This makes the method increasingly more widely used around the world. But work based on dendrogeomorphology has not been reported in China. In this article, we reviewed the development of the study on flash floods based on tree ring, briefly summarized the research progress, and discussed the advantages, limitations, and potential of this approach, so as to provide some reference information for relevant work in China.

Currently, there is a significant gap between the training objectives and the actual situation of electromechanical talents in higher vocational colleges. Many teachers in electromechanical departments do not meet the required qualifications and are unable to adapt to the developments of the new era. The talent training mode is insufficiently comprehensive, and the criteria for talent assessment are not unified. In response to these issues, it is necessary to promptly change the mindset, innovate educational ideas, focus on the present while planning for the future, clarify training objectives, adopt a dual education model that integrates production and education, strengthen the faculty, utilize their potential, and improve the overall educational quality to provide guarantees for talent development.

Knowledge of the presence of heavy metals in soils of agricultural areas is important to prevent their accumulation in cultivated plants. The objective of the present investigation was to evaluate the total concentrations and fractions of heavy metals Cd, Pb, Zn, Fe, Mn, Ni, Cu, Cr and Co in the tobacco-growing area of Pinar del Río, Cuba and their relationship with the physicochemical properties of soil. For the study, 59 samples of three types of soils were collected at 20 cm depth. The pseudo-total concentrations of metals in the soils are low and lower than the prevention values registered for Cuban soils. In general, the heavy metals studied present a high affinity for the most stable fractions of the soil, which means a low risk of transfer to the tobacco crop or accumulation in groundwater. The pseudo-total concentrations of heavy metals were low, below the alert values established for soils in the region. The heavy metals studied were mainly associated with the residual fraction, the second fraction with the highest association with metals was that linked to manganese and iron oxides. The principal component analysis showed that their main source is pedogenetic and that these elements are closely related to cation exchange capacity and calcium content.

Many financial crises have occurred in recent decades, such as the International Debt Crisis of 1982, the East Asian Economic Crisis of 1997–2001, the Russian economic crisis of 1992–1997, the Latin American debt Crisis of 1994–2002, the Global Economic Recession of 2007–2009, which had a strong impact on international relations. The aim of this article is to create an econometric model of the indicator for identifying crisis situations arising in stock markets. The approach under consideration includes data for preprocessing and assessing the stability of the trend of time series using higher-order moments. The results obtained are compared with specific practical situations. To test the proposed indicator, real data of the stock indices of the USA, Germany and Hong Kong in the period World Financial Crisis are used. The scientific novelty of the results of the article consists in the analysis of the initial and given initial moments of high order, as well as the central and reduced central moments of high order. The econometric model of the indicator for identifying crisis situations arising considered in the work, based on high-order moments plays a pivotal role in crisis detection in stock markets, influencing financial innovations in managing the national economy. The findings contribute to the resilience and adaptability of the financial system, ultimately shaping the trajectory of the national economy. By facilitating timely crisis detection, the model supports efforts to maintain economic stability, thereby fostering sustainable growth and resilience in the face of financial disruptions. The model's insights can shape the national innovation ecosystem by guiding the development and adoption of monetary and financial innovations that are aligned with the economy's specific needs and challenges.

In the teaching of graphic design, students' learning state and learning effect are poor due to the lack of attractiveness of teaching materials. In order to fully display the graphic design knowledge contained in totem patterns, a model based on the pattern elements of totem patterns was constructed. Through Marvelous Designer software, the display of totem visual effects under different pattern element configurations was realized, providing a basis for the comparative explanation of graphic design teaching. When designing the teaching content, based on the totem art culture, it has constructed three parts of teaching methods of plane composition, teaching contents of plane composition and teaching concepts of plane composition, which correspond to the material selection, composition and freehand brushwork skills of totem patterns in modeling creativity and expression techniques, and the range of material selection, composition form and connotation of plane design teaching, the specific application is realized through knowledge transfer.