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Global change factors differ in effect when acting alone and in a multi-factor background
No full textThe presence of multiple global change factors affects most ecosystems. Urban soils face stressors like heat, drought, road salt, nitrogen deposition, surfactants, and microplastics. Given that combined factors of global change have shown unpredictable effects, we here ask which individual factors have particularly negative effects in multifactorial contexts. We explore this through a subtractive design, comparing single-factor treatments (addition) to treatments where a specific factor is removed (subtraction). The results vary from predominantly negative, positive, to mixed effects. However, removing these factors from a multi-factor context generally improves soil properties and biological processes. Resource related factors enhance microbial activity individually but show no such benefit in multi-factor scenarios. Our findings highlight that the combined effects of factors often differ from their individual impacts. In restoration, priority should be given to mitigating factors with the strongest negative influence in multi-stressor contexts, rather than targeting those with significant isolated effects
How lipids suppress cavitation in biological fluids
No full textHypothesis
Cavitation in water under tension is often initiated at nanoscale hydrophobic surface defects that stabilize preexisting nanobubbles. We hypothesize that amphiphilic molecules, such as polar lipids, can adsorb onto these defects and suppress cavitation by removing nanobubble nucleation sites.
Simulations
To test this mechanism, we performed atomistic molecular dynamics simulations in combination with classical nucleation theory to model lipid bilayers and monolayer coatings at hydrophobic surfaces containing nanoscale pits and to investigate their response to applied negative pressures.
Findings
We find that lipids readily adsorb onto hydrophobic surfaces, conform to nanoscale features, and eliminate bubble-hosting cavities. This passivation shifts the cavitation-limiting step from nanobubble expansion at defects to rupture of lipid bilayers, which exhibit much higher cavitation resistance. These results provide a molecular basis for how amphiphilic additives enhance the stability of aqueous liquids against cavitation, even in the presence of unavoidable surface imperfections. This mechanism also offers a physically grounded explanation for how vascular plants sustain sap transport under substantial negative pressures despite structural heterogeneities in their water-conducting vessels
Modulatory effects of T-cell immunosuppression on pigeon protozoal encephalitis induced by Sarcocystis calchasi
No full textSarcocystis calchasi is the causative agent of Pigeon Protozoal Encephalitis, a neurological disease in pigeons. The biphasic disease is characterized by neurological signs in the chronic phase. Parasite stages are generally not associated with inflammatory brain lesions and the parasite has been suggested to modulate the host’s immune system. To test this hypothesis, pigeons experimentally infected with S. calchasi were T-cell immunosuppressed beginning from 14 days post infection (dpi) until the end of the experiment (59/60 dpi) and compared with immunocompetent animals. When scored histologically (sum encephalitis score consisting of lympho-histiocytic perivascular cuffs, lymphocytic encephalitis and gliosis), encephalitis was markedly less pronounced in immunosuppressed pigeons than in immunocompetent animals (6.8 ± 4.4 s.d. versus 11.2 ± 3.0 s.d.). Thus, the alleviation of the disease by immunosuppression supports the hypothesis of an immune-mediated mechanism rather than direct damage by the pathogen. Results from a second infection trial, where the effect of immunosuppression only during early (12–20 dpi) or late phase (30 dpi – end of experiment) was compared, did not show significant differences between both groups and suggest that immunomodulation is triggered during the early stage of parasite development by sporozoites and/or more likely merozoites
The value of leaders we trust and leaders who make us stronger: Exploring the distinct contributions of different components of identity leadership to group member outcomes
No full textThis study investigates the critical role of social identity in leadership, specifically examining identity leadership (IL) and the unique contributions of its four subdimensions: identity prototypicality, identity advancement, identity entrepreneurship, and identity impresarioship. To date, research has largely focused on the global construct of identity leadership and shown that in organizational contexts, it is a predictor of a range of outcomes, including group members’ burnout and organizational citizenship. However, the distinct roles of the four subdimensions remain little understood. Extending earlier findings, we address this gap by testing the hypothesis that the four subdimensions are differentially implicated in two key mechanisms that underlie the relationship between IL and group outcomes: (a) trust in the leader and (b) team identification. The present study explores this proposition by using structural equation modeling with latent factors to test a mediation model in 2020–2021 data from the Global Identity Leadership Development project (GILD; N = 7,855). As hypothesized, we found that identity prototypicality and identity advancement predominantly predicted greater trust in the leader, whereas identity entrepreneurship primarily predicted greater team identification. Contrary to our hypothesis, identity impresarioship showed a negative relation with trust. In turn, both trust in the leader and team identification were positively associated with organizational citizenship behavior (OCB), and negatively with burnout. We conclude by reflecting on the implications of these findings for both the theory and practice of leadership
Impacts of long-term land use and land cover change on land suitability potential in three sub-catchments of the Lake Tana Basin, Ethiopia
No full textPopulation growth and agricultural expansion cause major changes in land use and land cover (LULC) in Ethiopia. Cultivated lands are mostly expanding without land suitability evaluation. Consequently, crop yields are not increasing as expected. This is particularly the case in the highland catchments draining toward Lake Tana, where severe consequences such as deforestation and the degradation of soil and land can be observed. In this study, the impacts of long-term LULC dynamics on the land suitability potential for selected major crops in three sub-catchments of Lake Tana, Ethiopia (Gilgelabay, Gumara and Ribb), were evaluated. Time series of Landsat images from three periods (1988, 1998, and 2017) were classified. Land suitability was analyzed via a multi criteria approach based on spatial input data such as elevation, soil, and slope maps. The overall accuracy for all LULC classifications was good to very good (89.7% to 91.6%). Five major LULC classes were distinguished: agriculture, forest, shrub/bushland, grassland, and water. In all three catchments, the results revealed that agricultural land was the dominant land cover that expanded at the expense of the other land cover types to 80%-90% in all catchments in 2017. The rate of change in agricultural land in the Gilgelabay catchment (4041.3 ha/yr) was greater than that in the Gumara (1374.5 ha/yr) and Ribb (1362.3 ha/yr) catchments. This is possibly due to the availability of other LULC classes. The natural vegetation of Gilgelabay, Gumara, and Ribb has decreased by 16.0%, 10.5%, and 1.1%, respectively, over the past three decades. However, the present LULC change trends are unsustainable, and any remaining natural vegetation should be maintained. The results from the land suitability analysis revealed that the land suitability for teff, corn, and rice is likely to change with climate change in the future. To ensure sustainable land use management, modifying land use on the basis of land suitability should be preferred over traditional practices to improve crop production. This can be achieved in close collaboration with all stakeholders, including local communities, the government, and NGOs
Reversible biphasic model for isomerizations
No full textIsomerizations proceed from reactants R to products P, and back. Our reversible biphasic model assumes that the reaction is from R via the transition state species ‡ to P, and back. We derive the analytical solution of the rate equations. It allows simple applications to special cases. For example, for strongly exothermic reactions with negligible back reactions it brings about the same rate constant k as for transition state theory (TST). In contrast, for nearly or perfectly thermoneutral reactions, k is just half the TST reference. The results are exemplified for the nearly thermoneutral Cope rearrangement of mono deuterio-1,5-dimethylsemibullvalene
From Permits to Samples: Addressing Key Challenges for High-Quality Reference Genome Generation in Europe
No full textHigh-quality reference genome assemblies have become essential for deepening our understanding of biodiversity, yet obtaining them for many species remains surprisingly challenging. Drawing on experiences from the European Reference Genome Atlas (ERGA) community, we focus on permit and sample-handling procedures leading up to nucleic acid sequencing, covering tasks such as ensuring ethical and legal compliance, verifying accurate species identification, maintaining sample integrity during transport, and isolating high-quality DNA or nuclei. While many of the challenges and solutions we discuss are broadly relevant, our regulatory and logistical examples are primarily from Europe. By synthesising practical guidance, we highlight the crucial importance of taxonomic expertise, proper vouchering and biobanking, rigorous cold-chain management or alternative preservation methods, and emphasise adherence to packaging and shipping requirements for biological materials. We showcase examples spanning diverse regions, taxa and source materials, which underscore the importance of context-specific strategies and internationally harmonised protocols, particularly for metadata reporting. Our recommendations aim to support both small-scale projects and large initiatives, directing collective efforts to facilitate efficient sampling, vouchering and sample processing for future genomic studies
Infrared nanoscopy for subcellular chemical imaging
No full textInfrared (IR) nanoscopy represents a collection of imaging and spectroscopy techniques capable of resolving IR absorption on the nanometer scale. Chemical specificity is leveraged from vibrational spectroscopy, while light–matter interactions are detected by observing perturbations in the optical near field with an atomic force microscopy probe. Therefore, imaging is wavelength independent and has a spatial resolution on the nanometer scale, well beyond the classical diffraction limit. In this perspective, we outline the recent biological applications of scattering type scanning near-field optical microscopy and nanoscale Fourier-transform IR spectroscopy. These techniques are uniquely suited to resolving subcellular ultrastructure from a variety of cell types, as well as studying biological processes such as metabolic activity on the single-cell level. Furthermore, this review describes recent technical advances in IR nanoscopy, and emerging machine learning supported approaches to sampling, signal enhancement, and data processing. This emphasizes that label-free IR nanoscopy holds significant potential for ongoing and future biological applications
Redox-Responsive Self-Assembled Amphiphilic Nanosheets from Polyglycerol Sulfate–Lipoic Acid Copolymers for Targeted Cancer Drug Delivery
No full textTargeted drug delivery systems that are stimuli-responsive offer great potential for enhancing the therapeutic activity of drugs, decreasing off-target effects, and improving bioavailability. This proof-of-concept study introduces an amphiphilic drug delivery system (DDS) capable of loading hydrophobic cargo. Elevated glutathione (GSH) levels, characteristic of certain types of cancer cells’ microenvironment, degrade the nanostructures and release the cargo. Linear polyglycerol sulfate (LPGS), known for its excellent biocompatibility, is combined with lipoic acid (LA). LA facilitates the formation of cross-linked nanosheet amphiphiles sensitive to reductive conditions. Morphological changes are observed by scanning electron microscopy (SEM), cryogenic transmission electron microscopy (Cryo-TEM), and cryogenic electron tomography (Cryo-ET) upon UV irradiation (hν), creating a stable aggregate for loading hydrophobic cargo and assembling into sheets at elevated concentrations. The resulting material displays controlled release of model dyes under increased levels of GSH, tunable by the polymer size and LPGS:LA acid ratios. This behavior enhances targeted therapy and reduced off-target effects. Further loading with paclitaxel and subsequent release, together with in vitro assays, demonstrates the system’s compatibility with an anticancer drug
Marriage Markets and Match Making from Early Modernity to the Present
No full textLove and economics are usually considered to be opposites: While love is seen as an irrational, unexplainable and ungovernable feeling towards another person, economics is regarded as the art of egoistic, profit-oriented, rational calculations and actions. But are they, really? By examining a wide range of literary and historical sources throughout European modernity, the papers assembled in this volume investigate how the process of finding a partner or spouse interlaces love and economics. In their analysis of Early Modern marriage legislation, drama, Spanish novellas, Jane Austen’s novels, films, dating apps and more, they reveal major cultural-historical changes in the notions of love and economics, and stress the role that concepts of gender, epistemic discourse, and media play in their interrelated history. Yet, despite their differing findings, they all show one thing: that „opposition“ is far too simple a term to grasp the complicated relation of emotion and calculation