Symmetry in copper and silver cryptates

The cryptand ligands imBT (1,4,7,10,13,16,21,24-Octaaza-bicyclo[8.8.8]hexacosa-4,6,13,15,21,23-hexaene) and amBT (1,4,7,10,13,16,21,24-Octaazabicycl0[8.8.8]hexacosane) form interesting disilver(I) and trisilver(I) cryptates, as well as a dicopper(I) and a well studied average valence dicopper(1.5) cryptate. Detailed structural and spectroscopic studies of the silver cryptates show that complex equilibria exist in solution, and the trisilver form appears to be thermodynamically favoured, the additional stabilisation apparently being due to argentophilic interactions. An optically pure form of the dicopper(I) imBT cryptate was successfully obtained, and is undergoing X-ray diffraction studies aimed at determining whether a copper-copper interaction exists, by direct examination of the electron density. Synthetic studies aimed at introducing substitution to the imBT and amBT ligands were complicated by competing reactions. A strategy to modify cryptand cavity size by incorporating asymmetric tetraamine caps succeeded, yielding dicopper(I) and disilver(I) cryptates with properties intermediate between cryptates incorporating the related symmetric caps. Manganese(II) cryptates of imBT and amBT were investigated as potential MRl contrast agents, the iminocryptate showing surprisingly high relaxivity, despite the fact that no water molecules were located in the crystal structure. The observation of high mass peaks in the FAB mass spectra of imBT and amBT cryptates suggests the presence of 6+4 Schiff base condensation products, as well as the more abundant 3+2 products. It has not proved possible to isolate these molecules as yet, however initial studies aimed at a rational synthesis of the 6+4 condensation products were made, as these ligands could be of great interest for modelling the recently reported CUz site

Student Affairs in Canada in 2013 Perceptions, Trends, and an Outlook toward the Future

Chief Student Affairs Officers (CSAOs) are senior-level student affairs personnel. In 2011, 33 CSAOs responded to a national survey and provided a professional perspective on field development, student services, as well as predicted five-year trends for student affairs. In 2013, 17 CSAOs responded to the same survey and provided further information on these topics. Results indicated that attitudes towards diversity and technology remained stable between 2011 and 2013. We established that CSAOs have less positive attitudes towards research, evaluation, and assessment than they do towards communication and leadership. Here, we discuss at length the implications of these finding, as well as the potential for research into student affairs. In addition, we examine the continued professionalization of the CSAO field and note that research into CSAOs should be proactive instead of reactive.  Les directeurs des affaires étudiantes sont des membres du personnel des affaires étudiantes aux niveaux supérieurs. En 2011, 33 de ces directeurs ont répondu à un sondage national et fourni une perspective professionnelle sur la mise en valeur de leur domaine, sur les services aux étudiants, ainsi que sur leurs prédictions des tendances des cinq prochaines années pour les affaires étudiantes. En 2013, 17 directeurs ont répondu au même sondage et ont fourni plus de données sur ces mêmes sujets. Les résultats indiquaient que les attitudes envers la diversité et la technologie étaient demeurées stables entre 2011 et 2013. Nous avons pu établir que les directeurs présentent des attitudes moins positives envers la recherche, l’évaluation et les épreuves, qu’envers la communication et le leadership. Nous nous attardons ici sur les implications de ces découvertes, de même que sur leur potentiel pour la recherche au sujet des affaires étudiantes. Nous discutons aussi de la professionnalisation du domaine des directeurs des affaires étudiantes et notons que la recherche au sujet des directeurs doit être proactive plutôt que réactive

Managing the Three Gorges Dam to Implement Environmental Flows in the Yangtze River

The construction of the Three Gorges Dam, along with other development in the Yangtze River basin, has had profound consequences for the river's flow and sediment regime. This has had major impacts on the geomorphology and ecology of the river downstream of the dam, with related impacts on biodiversity, including fish populations, livelihoods, and water security in the middle and lower Yangtze. Changes to fish populations have included a fall of around 90% in the total number of fish fry for the four economically-important Chinese carp species, caused at least in part by alterations in the flow regime. In response, there has been increased research into the significance of flow regimes for Chinese carp, as well as other aspects of river health. A partnership between the Chinese Government, the dam operator, scientists, and conservationists has led to pilot environmental flow releases over a 5-year period in an attempt to mitigate some of these impacts. Subsequent monitoring has shown that numbers of fish fry are increasing from the low they had fallen to in 2008. Drawing on lessons from the pilot environmental flow releases, in October 2015 the official regulations that govern operations of the Three Gorges Dam were amended to incorporate additional objectives, including incorporating environmental flow releases as part of the routine operation of the dam. This paper describes the processes that led to the environmental flow program from Three Gorges, a review of monitoring data collected during the pilot environmental flow releases, the subsequent amendment of the dam operating rules, and prospects for expanding environmental flow implementation in the Yangtze River in coming years

Genome-wide association, prediction and heritability in bacteria with application to Streptococcus pneumoniae

Whole-genome sequencing has facilitated genome-wide analyses of association, prediction and heritability in many organisms. However, such analyses in bacteria are still in their infancy, being limited by difficulties including genome plasticity and strong population structure. Here we propose a suite of methods including linear mixed models, elastic net and LD-score regression, adapted to bacterial traits using innovations such as frequency-based allele coding, both insertion/deletion and nucleotide testing and heritability partitioning. We compare and validate our methods against the current state-of-art using simulations, and analyse three phenotypes of the major human pathogen Streptococcus pneumoniae, including the first analyses of minimum inhibitory concentrations (MIC) for penicillin and ceftriaxone. We show that the MIC traits are highly heritable with high prediction accuracy, explained by many genetic associations under good population structure control. In ceftriaxone MIC, this is surprising because none of the isolates are resistant as per the inhibition zone criteria. We estimate that half of the heritability of penicillin MIC is explained by a known drug-resistance region, which also contributes a quarter of the ceftriaxone MIC heritability. For the within-host carriage duration phenotype, no associations were observed, but the moderate heritability and prediction accuracy indicate a moderately polygenic trait.Peer reviewe

Airborne laser scanning reveals increased growth and complexity of boreal forest canopies across a network of ungulate exclosures in Norway

Large herbivores are often classed as ecosystem engineers, and when they become scarce or overabundant, this can alter ecosystem states and influence climate forcing potentials. This realization has spurred a call to integrate large herbivores in earth system models. However, we lack a good understanding of their net effects on climate forcing, including carbon and energy exchange. A possible solution to this lies in harmonizing data across the myriad of large herbivore exclosure experiments around the world. This is challenging due to differences in experimental designs and field protocols. We used airborne laser scanning (ALS) to describe the effect of herbivore removal across 43 young boreal forest stands in Norway and found that exclusion caused the canopy height to increase from 1.7 0.2 to 2.5 0.2 m (means SE), and also causing a marked increase in vertical complexity and above-ground biomass. We then go on to discuss some of the issues with using ALS; we propose ALS as an approach for studying the effects of multiple large herbivore exclosure experiments simultaneously, and producing area-based estimates on canopy structure and forest biomass in a cheap, efficient, standardized and reproducible way. We suggest that this is a vital next step towards generating biome-wide predictions for the effects of large herbivores on forest ecosystem structure which can both inform both local management goals and earth system models biomass, herbivory, large herbivores, LiDAR, moose, remote sensingpublishedVersio

Integrative taxonomy reveals a new species, Nephroma orvoi, in the N. parile species complex (lichenized Ascomycota)

Our knowledge of the diversity and distribution of many groups of lichens remains poor due to unclear species boundaries and challenging species identification. We have studied the medium sized to large foliose lichen Nephroma parile, which is known to be heterogeneous in chemistry and genetics. Our aim has been to assess the potential presence of evolutionary significant units within the Nephroma parile species complex that may be worthy of recognition at species level. Using phylogenetic analysis of the fungal DNA-barcode marker (ITS) in combination with studies of morphology and chemistry, we discover two distinct lineages in the N. parile species complex. For the strongly supported clade that corresponds to chemotype II, we describe the new species Nephroma orvoi. The new species is known from Norway, Sweden, Finland, Switzerland, Canada (Alberta and British Columbia), USA (Washington), and Greenland.publishedVersio

Functional traits of alpine plant communities show long-term resistance to changing herbivore densities

Herbivores shape vegetation by suppressing certain plant species while benefitting others. By thus modifying plant species functional composition, herbivores affect carbon cycling, albedo, vegetation structure and species' interactions. These effects have been suggested to be able to counteract the effects of increasing temperatures on vegetation in alpine environments. Managing the dominant large ungulates in these ecosystems could thus provide a tool to mitigate climate change effects. However, it is possible that legacy effects of past grazing will dampen ungulate impacts on vegetation. We shed a light on this topic by investigating the short- and long-term effects of varying sheep densities on the plant trait composition in the Norwegian alpine tundra with centuries-long of intensive grazing history. In the first part of our study, we quantified the effects of sheep on the plant community functional trait composition at different elevations and under moderate and low productivity in. We combined data from two long-term (14 and 19 yr) sheep fence experiments and showed that differences in sheep densities did not affect plant trait composition, irrespective of productivity. However, in the second part of our study, we showed that the plant trait composition in mainland (that has been grazed for centuries) differed from vegetation on islands which have been herbivore-free. Taken together, these results suggest that sheep have an effect on the alpine plant communities on historical time scales covering centuries, but that the resulting sheep grazing resistant/tolerant communities may not respond to shorter-term (14 and 19 yr) changes in sheep densities, that is, at temporal scales relevant for ecosystem management. Furthermore, we showed that the plant trait composition at the site with low productivity had gone through a temporal trait change independent of sheep treatment, potentially due to increased temperatures and precipitation, suggesting that sheep may not be able to counteract climatic impacts in the areas with centuries-long grazing history.publishedVersio

What are the effects of herbivore diversity on tundra ecosystems? : A systematic review protocol

Funding Information: The project was funded by the Icelandic Research Fund (Grant Nr. 217754) and the European Union’s Horizon 2020 programme (CHARTER project, Grant Agreement Nr. 869471). Funding for open access publication was provided by the Agricultural University of Iceland. The funding bodies had no influence in the design of the study and collection, analysis and interpretation of data. Funding Information: This study is a contribution of the Herbivory Network (http://herbivory.lbhi.is), a UArctic Thematic Network. Publisher Copyright: © 2022, The Author(s).Background: Changes in the diversity of herbivore communities can strongly influence the functioning of northern ecosystems. Different herbivores have different impacts on ecosystems because of differences in their diets, behaviour and energy requirements. The combined effects of different herbivores can in some cases compensate each other but lead to stronger directional changes elsewhere. However, the diversity of herbivore assemblages has until recently been a largely overlooked dimension of plant–herbivore interactions. Given the ongoing environmental changes in tundra ecosystems, with increased influx of boreal species and changes in the distribution and abundance of arctic herbivores, a better understanding of the consequences of changes in the diversity of herbivore assemblages is needed. This protocol presents the methodology that will be used in a systematic review on the effects of herbivore diversity on different processes, functions and properties of tundra ecosystems. Methods: This systematic review builds on an earlier systematic map on herbivory studies in the Arctic that identified a relatively large number of studies assessing the effects of multiple herbivores. The systematic review will include primary field studies retrieved from databases, search engines and specialist websites, that compare responses of tundra ecosystems to different levels of herbivore diversity, including both vertebrate and invertebrate herbivores. We will use species richness of herbivores or the richness of functional groups of herbivores as a measure of the diversity of the herbivore assemblages. Studies will be screened in three stages: title, abstract and full text, and inclusion will follow clearly identified eligibility criteria, based on their target population, exposure, comparator and study design. The review will cover terrestrial Arctic ecosystems including the forest-tundra ecotone. Potential outcomes will include multiple processes, functions and properties of tundra ecosystems related to primary productivity, nutrient cycling, accumulation and dynamics of nutrient pools, as well as the impacts of herbivores on other organisms. Studies will be critically appraised for validity, and where studies report similar outcomes, meta-analysis will be performed.Peer reviewe