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Urban Lasius niger ants more readily accept low concentration sucrose solution than rural ants
No full textUrbanisation causes broad changes in biotic and abiotic factors, which are often detrimental to animals. While extensive attention has been focussed on food resources for pollinators, comparatively little research has examined resources for aphidophagous insects. Many ants, such as Lasius niger, belong to this group of insects and rely on honeydew secretions for the majority of their carbohydrate intake. Ants will also often reject sugar solutions that are of lower concentration than those they are used to consuming. Here, we ask whether L. niger ants from urban environments show differential acceptance to various sucrose solution molarities compared with rural populations. We offered outgoing ants on active foraging trails drops of sucrose solutions over a range of molarities (0.125, 0.25, 0.5, 1, and 2 M), and quantified acceptance. Acceptance was scored using a simple behavioural measure of whether the ant remained in contact with the sucrose drop for over 3 s (full acceptance), broke away from the drop within 3 s but remained in the area and eventually drank to satiation (partial acceptance), or did not drink to satiation and walked away (rejection). Urban ants showed a significantly higher acceptance of all sucrose molarities than rural ants, with this difference especially pronounced at lower molarities. This may indicate that they are under nutritional stress for carbohydrates, either in quality or quantity, as well as heightened motivation to exploit any available food source under the pressures of urban environments
Landscape effects on global soil pathogenic fungal diversity across spatial scales
No full textGrowing evidence has shown that, apart from local environmental factors, changes in landscape-level factors by accelerated land-use change can also shape soil pathogenic fungal diversity. However, the global representativeness of such patterns remains unclear. Here, we assess how pathogenic fungal diversity in 511 soil samples worldwide responds to landscape factors, including landscape complexity index based on eight landscape metrics and quantity of different land cover types across six spatial scales (i.e., surrounding landscape, 250 m to 10,000 m radii from the sampling coordinate). We find that while soil variables explain over half of the variance, pathogenic fungal alpha diversity increases with landscape complexity and crop cover proportion, but decreases with grass and tree cover proportion, together explaining 23.4% of the total variance. Landscape factors have weaker impacts on beta diversity, explaining 13.0% of the variance. Across spatial scales, grassland ecosystems exhibit increasingly stronger responses to landscape variables compared to forest ecosystems. Landscape factors have a higher relative contribution to root-associated fungi than leaf/fruit/seed-associated fungi. Our results emphasize the importance of local factors and the complementary role of landscape patterns in shaping global soil pathogenic fungal distributions, highlighting scale-dependent effects across ecosystems and fungal functional groups
Dissimilarity among soil restoration practices influences soil functions and plant biomass: A functional group approach
No full textSoil restoration amendments are of great importance to maintain soil health. However, the effects of joint application of multiple (more than two) restoration amendments are rarely addressed. We selected nine restoration amendments allocated to three functional groups: organic amendments, inorganic amendments and microbial inoculation. We investigated effects of amendment functional dissimilarity, i.e. if amendments from diverse groups can perform better than amendments from the same group. By maintaining a balanced selection across three groups, we increased the number of amendments to 3, 6 and 9 to unravel its impacts. We further tested if such combinations enhanced resistance against drought by comparing plant biomass, soil enzyme activities, and soil physiochemical properties under drought (30 % water holding capacity) and well-watered conditions (60 % water holding capacity). Increasing the number of restoration amendments increased soil pH toward neutrality, driven primarily by inorganic amendments such as bentonite and vermiculite, irrespective of watering conditions, while improvements in aggregate stability and plant growth occurred only under well-watered conditions. Three amendments from diverse functional groups maximized plant growth and soil multifunctionality under well-watered conditions. On the other hand, under drought conditions, individual amendments- such as straw and vermiculite- showed the strongest positive effects on the overall soil functional performance and plant biomass, exceeding those of combined treatments. Our work highlights the importance of applying restoration amendments from diverse functional groups under well-watered conditions and applying single restoration amendments facing drought stress
Thiophene Derivatives as Versatile Precursors for (Hetero)Arene and Natural Product Synthesis
No full textThiophenes and their saturated analogues are versatile C4-building blocks used to construct structurally intricate ring systems found in various biologically active structures. For instance, thiophenes can undergo dearomative cycloaddition reactions under photocatalytic conditions forming highly substituted benzenes. Thiophene S-oxides and S,S-dioxides have emerged as valuable precursors for the construction of complex frameworks in (4 + 2)/retro-(4 + 1) cascade reactions through cheletropic release of SO or SO2, respectively. In addition, 2,5-dihydrothiophenes can be rapidly converted into furans or pyrroles via pericyclic cascade reactions. The installation of a tetrahydrothiophene followed by reductive deletion of the sulfur atom has been demonstrated to be a powerful method for the cis-dialkylation of electron-poor olefins. The ability to generate highly complex, aromatic scaffolds and quaternary stereocenters makes thiophene compounds valuable intermediates for synthesizing natural products and bioactive molecules, which are important for crop science and medicinal chemistry. This minireview provides an overview of strategies for using these sulfur-containing heterocyclic precursors in challenging synthetic applications
High-spin state dynamics and quintet-mediated emission in intramolecular singlet fission
No full textHigh-spin states in molecular systems hold significant interest for applications ranging from optoelectronics to quantum technologies. Spin states generated in intramolecular singlet fission are of particular relevance, yet the mechanisms controlling triplet-pair formation are not fully understood – especially the involvement of quintet states in luminescence at room temperature remains experimentally elusive. Here, we investigate high-spin state formation and emission in dimers and trimers comprising multiple diphenylhexatriene units. We demonstrate the formation of pure quintet states in all these oligomers, with quintet-mediated emission dominating delayed fluorescence up to room temperature. By distinguishing between the formation of weakly exchange-coupled triplet pairs and triplet excitons generated by intersystem crossing, we identify the methylated trimer as the only oligomer exhibiting exclusively the desired singlet fission route. These findings establish quintet-mediated delayed emission as a distinct spin-selective pathway and show how molecular structure directs high-spin formation, opening opportunities for room-temperature molecular quantum technologies
Evaluation of Laboratory Techniques for the Diagnosis of Leptospira-Associated Equine Recurrent Uveitis (ERU) With Focus on the Goldmann-Witmer Coefficient
No full textPurpose
To evaluate different laboratory procedures for determining the etiologic diagnosis of equine recurrent uveitis regarding intraocular infection with Leptospira spp. and to establish a diagnostic guideline.
Material and Methods
Eighty horses with a history of ERU were ophthalmologically examined. Serum and aqueous humor were collected. Total protein, albumin level, and MAT against Leptospira spp. were evaluated on serum and aqueous humor. PCR for Leptospira spp., EHV-1 and -4 was performed on aqueous humor. Goldmann-Witmer coefficient (GWC) and C-value (CC) were calculated based on MAT. In 42 cases, an additional ELISA was initiated.
Results
Forty-six female and 34 male horses of different breeds (mean age 10.9 years; range 3 to 31) were included. By MAT 56/80 horses (70.0%) were identified seropositive for Leptospira spp. MAT results were positive for Leptospira spp. in aqueous humor of 47/80 (58.8%) patients. PCR tested 16/80 (20.0%) positive, ELISA detected 13/42 (31.0%) positive. Neither EHV-1 nor EHV-4 were detected by PCR. Calculating GWC gives evidence suggestive of intraocular involvement with Leptospira spp. in 53/80 (66.3%) at the level ≥ 3. Setting GWC ≥ 3 as gold standard, ELISA and C ≥ 2 closely matched this threshold, showing high accuracy (95.2%; 91.3%), sensitivity (86.7%; 84.9%), and strong agreement (V = 0.90; V = 0.81). PCR was less accurate (53.8%) and sensitive (30.2%) compared to GWC.
Conclusion
Within this setting, GWC achieved the highest number of positive results for detecting intraocular involvement of Leptospira spp. when compared to PCR, ELISA, and C-value
Small but mighty: Impact hazards from iron Near-Earth Objects
No full textSmall asteroids can impact Earth unexpectedly, as demonstrated by the Chelyabinsk event in 2013. The warning times are likely to be short, and the first tools for fast hazard predictions have been developed in the last years for encounters with rocky or cometary objects, which quickly fragment in the atmosphere and cause airbursts. However, in the projectile diameter range <20 m (and possibly up to 50 m), the ground effects caused by the entry of iron asteroids, denser and stronger than other objects, are much more severe than for rocky asteroids of equal energy. The existing prediction tools do not provide reliable results for such scenarios. In this work, we first review historical iron falls and related damage, and then discuss the applicability of existing semi-analytical models for iron falls. We compare the calculated damage caused by the Barringer crater formation with early estimates. Finally, we present our new model, which allows us to estimate the maximum damage envelope caused by iron meteoroids with unknown strength
Directing the Mobility of Guest Molecules in Nanoporous Materials by Linearly Polarized Light
No full textFor the advancements of photoresponsive materials with tunable properties, the usage of multidimensional signals is desired. Using the polarization of the light in addition to the wavelength represents a further parameter to control the materials properties. Here, the first-time dynamic and reversible manipulation of the guest-host properties of a nanoporous material by linearly polarized light (LPL) is reported. The material is based on a metal–organic framework (MOF) with photoresponsive azobenzene side groups covalently connected to the MOF structure. The azobenzene moieties are reversibly reoriented by LPL, making the MOF structure and, thus, the pores anisotropic. As a result, the mobility of the guest molecules in the pores of the initially isotropic material becomes anisotropic, which can be dynamically controlled by the light polarization. The experiments by impedance spectroscopy are supported by molecular dynamics (MD) simulations. The study shows that the light polarization can be a further parameter to modify the material properties, allowing a more complex and more refined level of control for smart materials
Temporal governance and accountability costs of Beijing's digital citizen request system
No full textPrior literature highlights democracies' struggle to cope with today's rapid socio-economic changes, contrasting with more adept responses in authoritarian systems. This study makes a first attempt to explain the perceived speediness in an authoritarian setting. By focusing on Beijing's digital service request system, Jiesu Jiban, we argue that in creating request categories, standardizing cadres' reactions to requests, and designing decision pathways, Jiesu Jiban is not only an instrument to deal with increasing complexity and acceleration of socio-economic development, but the system itself also creates acceleration. It does so by categorizing, specifying, and standardizing service requests and response procedures and by channeling these through a digital infrastructure. We show that the datafication of governing citizens' request increases pressure for frontline administrators co-producing a system of responsibility without accountability for the central government
Multinational and Multimodal Character Framing of Political Candidates in Online News: Do Political and Media System Classifications Matter?
No full textAn evolving body of research generally referred to as visual politics has brought the heavy research focus on linguistic modalities of political communication closer to parity with visual emphasis. The study reported here transcends this schism by joining momentum toward multimodality as an ontological departure point for research. We expanded an existing visual instrument into a multimodal one and provided evidence that it reliably captures character framing of political candidates (stateliness, compassion, mass appeal, ordinariness, and sure loser) in German, Polish, and United States commercial online news. We focused on election coverage in these countries because they represent three distinct political and media systems (democratic-corporatist, polarized-pluralist, and hybrid) of the Global North. The quantitative content analysis sample we used spans 2,688 online news stories with seven political candidates identified in 6,560 cases across six modalities (still images, moving images, frozen video images, text, audio, and superimposed text). We found support for the hypothesis that political and media system latencies affect how news media frame the character traits of political candidates in both visual and linguistic modalities. Specifically, the competitive tendencies of majoritarian democracies manifested more clearly as candidate-centered, simplistic, and polarizing character framing in US media content than in journalistic output of multiparty consensus democracies. For example, US news media were more consistent in their portrayal of election winners and losers than German and Polish news media, emphasizing stateliness, compassion, and ordinariness in the winner while unambiguously assigning the negative sure loser frame to the election loser