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High university dropout rates have negative outcomes for both students and society. Supportive student cooperation may play an important role in preventing intentions to quit by promoting engagement and reducing loneliness among students. There is a need for more knowledge about the association of student cooperation, academic engagement, loneliness, and intentions to quit. This study, therefore, examined the association between student cooperation and intentions to quit via emotional and behavioral engagement and loneliness. These associations were tested by using latent structural equation modelling with data from a survey conducted among 356 first-year students. The results indicated two separate paths from student cooperation to intentions to quit, one via emotional engagement and the other via loneliness. The findings thus suggest that facilitating cooperation may prevent students' intentions to quit by enhancing emotional engagement and reducing feelings of loneliness.

This paper examines the international welfare effects of two types of hydrogen-support policies: subsidies for green electrolysis-hydrogen production and subsidies for hydrogen consumption. Using a short-term partial equilibrium model of the integrated electricity and hydrogen markets in seven Western European countries, we find that, in this short-term framework under given generation capacities and an existing carbon-pricing regime, hydrogen-consumption subsidies reduce domestic emissions but may increase emissions abroad, while green-electrolysis subsidies raise emissions both domestically and internationally due to higher electricity demand. Both policies benefit hydrogen users, but increase electricity prices, harming electricity users. Overall, both policies and, in particular, production support for electrolyzers, negatively affect welfare in the short term, though some countries may gain from trade. In scenarios with higher gas and carbon prices, hydrogen subsidies, especially for power-to-gas producers, can improve overall welfare in the short term.Key policy insightsThe short-term effectiveness and efficiency of national hydrogen policies depend on the degree of integration and interaction between international electricity and hydrogen markets.In the short term and under constrained renewable capacity, subsidizing hydrogen consumers effectively reduces domestic emissions while the economic benefits remain mainly domestic, but it may raise emissions elsewhere.Even in a situation of strongly internationally integrated markets, domestic general consumption support results in a lower loss of welfare than technology-constrained production support in the short term.

This study examines the impact of adopting climate smart agriculture practices (CSAPs) on Tanzania's farm production, productivity, and food security. A cross-sectional design was used with 407 smallholder maize households in the Ruvuma Region. Logit models examined the determinants of CSAP adoption and ordinary least squares was used to assess the effects of CSAP adoption on maize production and productivity. The Tobit model established a link between CSAP adoption and household food security. This study found that financial resources and knowledge of climate change are important for CSAP adoption. The adoption of certain practices, such as drought-tolerant seeds, fertilisers, mulching, and crop rotation, showed a significant positive association with maize yield, while agroforestry, compost, and cover crops had negative associations. However, no significant effect of CSA practices on food security was found. Policy implications from the study are provided.

A bstract We construct dimer graphs for relativistic Toda chains associated with classical untwisted Lie algebras of A, B, C 0 , C π , D types and twisted A, D types. We show that the Seiberg-Witten curve of 5d $$ \mathcal{N} $$ N = 1 pure supersymmetric gauge theory of gauge group G is a spectral curve of the relativistic Toda chain of the dual group G ∨ .

Fused silica is widely used in high-end manufacturing owing to its excellent optical and mechanical properties. However, its inherent hardness and brittleness make it prone to crack initiation and subsurface damage during grinding, which compromises surface integrity and component performance. Although numerous studies have investigated material removal and damage evolution mechanisms under single-abrasive loading, the successive multi-abrasive interaction that occurs in practical grinding remains insufficiently understood, particularly regarding stress field evolution and crack propagation. To address this gap, the study investigates the mesoscale damage evolution of fused silica during successive scratching. Smoothed particle hydrodynamics (SPH) simulation results reveal that cracks beneath the 1st scratch remain relatively stable, exhibiting typical single-abrasive behavior. In contrast, the subsurface damage depth beneath the 2nd scratch initially increases with scratch spacing L-d and then stabilizes. Moreover, the subsurface damage depth along the mid-plane between scratches follows a "first increase, then decrease" trend with L-d, peaking at approximately twice the scratch width (2a), where complex interaction between lateral and median cracks occur. Stress field analysis combined with nanoscratch experiments further confirms that scratch spacing is the key factor controlling stress field coupling and crack evolution. At small spacings (L-d < a), overlapping stress fields intensify existing crack propagation. At intermediate spacings (L-d = similar to 2a), coupled stress fields at the mid-plane trigger interlaced lateral and median cracks, producing complex damage morphologies. At large spacings (L-d > 2.5a), the stress fields become decoupled, resulting in largely independent crack growth and significantly reduced damage severity. This study offers new mesoscale insights into crack evolution and damage mechanism under multi-abrasive interaction in hard and brittle materials. The findings offer both theoretical and experimental foundations for subsurface damage control and surface integrity improvement in the grinding of such materials.