Search

Abstract The application of graph theory to metacommunity ecology allows a deeper analysis of the effect of network structure on diversity patterns. Here, we set out to test the role of network centrality metrics and environmental characteristics in diversity patterns of pond macroinvertebrate metacommunities. We tested two approaches to construct the networks: one used the percolation distance, whereas the other was based on a community‐contingent distance. The role of each patch within the network was then analyzed using its centrality value. Later, we analyzed the relationships between the macroinvertebrate diversity and centrality metrics for four study sites. The calculated diversity metrics cover different facets of biodiversity at two scales: pond and pondscape. Environmental characteristics of the studied ponds were also included. All relationships were tested considering the entire macroinvertebrate dataset, but also differentiated by dispersal mode (i.e., active vs. passive) and considering the two types of network approaches analyzed. The results were mostly consistent when comparing the network approaches used. Centrality metrics tended to be positively related to alpha and negatively to beta diversity. Environmental uniqueness showed a positive effect on beta diversity metrics, regardless of the dispersal mode. We only observed a weak negative relationship between eutrophication and species richness of active dispersers. Pond size showed a positive effect on both alpha and beta diversity, but was detected more frequently on alpha diversity metrics. We could not find evidence for a clear negative effect of habitat degradation on diversity. We found a greater importance of environmental characteristics versus the centrality metrics for both alpha and beta diversity of active dispersers, while a combination of their contributions for passive dispersers. An unexpected importance of centrality was observed for alpha diversity of passive dispersers. Using empirical data, we demonstrate that the centrality of a patch in an undirected network affects diversity regardless of the approach used to construct the networks, with a higher influence at local scale regardless of the dispersal mode. This study broadens knowledge of the relationships between environmental features and network centrality, demonstrating the important role of centrality as a determinant of diversity in metacommunities.

Dengue virus (DENV) is a public health challenge across the tropics and subtropics. Currently, there is no licensed prophylactic or antiviral treatment for dengue. The novel DENV inhibitor JNJ-1802 can significantly reduce viral load in mice and non-human primates. Here, using a mechanistic viral kinetic model calibrated against viral RNA data from experimental in-vitro infection studies, we assess the in-vitro inhibitory effect of JNJ-1802 by characterising infection dynamics of two DENV-2 strains in the absence and presence of different JNJ-1802 concentrations. Viral RNA suppression to below the limit of detection was achieved at concentrations of >1.6 nM, with a median concentration exhibiting 50% of maximal inhibitory effect (IC50) of 1.23x10-02 nM and 1.28x10-02 nM for the DENV-2/RL and DENV-2/16681 strains, respectively. This work provides important insight into the in-vitro inhibitory effect of JNJ-1802 and presents a first step towards a modelling framework to support characterization of viral kinetics and drug effect across different host systems.

The spatial isolation gradient of communities and the gradient in the species dispersal ability are recognized as determinants of biodiversity in metacommunities. In spite of this, mean field models, spatially explicit models, and experiments were mainly focused on idealized spatial arrangements of communities leaving aside the combining role of dispersal and isolation gradients in metacommunity processes. Consequently, we have an incipient understanding of the role of the real spatial arrangement of communities on biodiversity patterns. We focus on six metacommunities for which confident information about the spatial arrangement of water bodies is available. Using coalescent metacommunity models and null models that randomize the location of water bodies, we estimated the potential effect of the landscape on biodiversity and its dependence on species dispersal ability. At extremely low or high dispersal abilities, the location of ponds does not influence diversity because different communities are equally affected by the low or high incoming dispersal. At intermediate dispersal abilities, peripheral communities present a much lower richness and higher beta diversity than central communities. Moreover, metacommunities from real landscapes host more biodiversity than randomized landscapes, a result that is determined by the heterogeneity in the geographic isolation of communities. In a dispersal gradient, mass effects systematically increase the local richness and decrease beta diversity. However, the spatial arrangement of patches only has a large importance in metacommunity processes at intermediate dispersal abilities, which ensures access to central locations but limits dispersal in isolated communities. The ongoing reduction in spatial extent and simplification of the landscape may consequently undermine the metacommunity processes that support biodiversity, something that should be explicitly considered in preserving and restoring strategies.

IntroductionIn concussion, clinical and physiological recovery are increasingly recognized as diverging definitions. This study investigated whether central microglial activation persisted in participants with concussion after receiving an unrestricted return-to-play (uRTP) designation using [18F]DPA-714 PET, an in vivo marker of microglia activation.MethodsEight (5 M, 3 F) current athletes with concussion (Group 1) and 10 (5 M, 5 F) healthy collegiate students (Group 2) were enrolled. Group 1 completed a pre-injury (Visit1) screen, follow-up Visit2 within 24 h of a concussion diagnosis, and Visit3 at the time of uRTP. Healthy participants only completed assessments at Visit2 and Visit3. At Visit2, all participants completed a multidimensional battery of tests followed by a blood draw to determine genotype and study inclusion. At Visit3, participants completed a clinical battery of tests, brain MRI, and brain PET; no imaging tests were performed outside of Visit3.ResultsFor Group 1, significant differences were observed between Visits 1 and 2 (p < 0.05) in ImPACT, SCAT5 and SOT performance, but not between Visit1 and Visit3 for standard clinical measures (all p > 0.05), reflecting clinical recovery. Despite achieving clinical recovery, PET imaging at Visit3 revealed consistently higher [18F]DPA-714 tracer distribution volume (VT) of Group 1 compared to Group 2 in 10 brain regions (p < 0.001) analyzed from 164 regions of the whole brain, most notably within the limbic system, dorsal striatum, and medial temporal lobe. No notable differences were observed between clinical measures and VT between Group 1 and Group 2 at Visit3.DiscussionOur study is the first to demonstrate persisting microglial activation in active collegiate athletes who were diagnosed with a sport concussion and cleared for uRTP based on a clinical recovery.

Objectives To assess the effects of a 4-week randomised controlled trial comparing an outdoor gait-training programme to reduce contact time in conjunction with home exercises (contact time gait-training feedback with home exercises (FBHE)) to home exercises (HEs) alone for runners with exercise-related lower leg pain on sensor-derived biomechanics and patient-reported outcomes.Design Randomised controlled trial.Setting Laboratory and field-based study.Participants 20 runners with exercise-related lower leg pain were randomly allocated into FBHE (4 male (M), 6 female (F), 23±4 years, 22.0±4.3 kg/m2) or HE groups (3 M, 7 F, 25±5 years, 23.6±3.9 kg/m2).Interventions Both groups completed eight sessions of HEs over 4 weeks. The FBHE group received vibrotactile feedback through wearable sensors to reduce contact time during outdoor running.Primary and secondary outcome measures Patient-reported outcome measures (PROMs) and outdoor gait assessments were conducted for both groups at baseline and 4 weeks. PROMs were repeated at 6 weeks, and feedback retention was assessed at 6 weeks for the FBHE group. Repeated measures analyses of variance were used to assess the influence of group and timepoint on primary outcomes.Results The FBHE group reported increased function and recovery on PROMs beyond the HE group at 6 weeks (p

This dataset is related to the research article entitled “Effects of morphology and sediment permeability on coastal lagoons’ hydrological patterns” (W. Meredith, X. Casamitjana, X. D. Quintana, A. Menció) [1], and was obtained in the La Pletera salt marshes in Catalunya between 2016 and 2019, to model the water balance and salinity fluctuations of 6 permanent lagoons using the General Lake Model (GLM). As no inflow and outflow data were available, water level and bathymetric data were used to calculate the net balance of inflows and outflows according to the observed daily volume fluctuations. Meteorological data were obtained from the L´Estartit Meteorological station north of the lagoons. Daily solar radiation was measured in Mas Badia (La Tallada, ∼10km from the La Pletera) in 2016 and 2017 and in situ with radiation sensors in 2018 and 2019. Together with the bathymetry and water levels of the lagoons, calculated inflows and calibrated salinity and temperature data are provided to further confined coastal lagoons system modeling where inflow and outflow data are not available. Meteorological data and observed lagoon salinity and temperature are provided for comparison. As this is one of the few datasets that have modeled coastal water bodies less than 3m in depth using the GLM, the data presented here can be useful in stress testing the General Lake Model to other coastal lagoon systems, as well as to other global aquatic ecosystems.

A new teaching assistant model was adopted and qualitatively assessed for the general chemistry laboratory, in which both an undergraduate and a graduate teaching assistant provided instruction to students during the lab. Verbal interactions between graduate and undergraduate teaching assistants were recorded, transcribed, and coded using the modified Laboratory Observation Protocol for Undergraduate STEM (LOPUS). The codes were applied to capture how discussions, questioning, and explanations were conducted. In addition, the content discussed was coded to identify specific areas that pose challenges for students. Sizable differences were not observed between the number of interactions of the initiation, explanation, and questioning codes between graduate and undergraduate teaching assistants. Of the interactions, 77% focused on questions and discussions regarding the experimental setup. Discussions on the implications with regards to the effective use of undergraduate and graduate teaching assistants in chemistry laboratories are included.

Nanostructured superconductors allow dissipationless electrical transport to be exploited in technologically relevant devices. Here, the authors follow how detrimental fluctuations of the superconducting order parameter evolve in Al atomic contacts as their width is controlled by electromigration.

Understanding microbial growth and metabolism is a key learning objective of microbiology and biotechnology courses, essential for understanding microbial ecology, microbial biotechnology and medical microbiology. Chemostat cultivation, a key research tool in microbial physiology that enables quantitative analysis of growth and metabolism under tightly defined conditions, provides a powerful platform to teach key features of microbial growth and metabolism. Substrate-limited chemostat cultivation can be mathematically described by four equations. These encompass mass balances for biomass and substrate, an empirical relation that describes distribution of consumed substrate over growth and maintenance energy requirements (Pirt equation), and a Monod-type equation that describes the relation between substrate concentration and substrate-consumption rate. The authors felt that the abstract nature of these mathematical equations and a lack of visualization contributed to a suboptimal operative understanding of quantitative microbial physiology among students who followed their Microbial Physiology B.Sc. courses. The studio-classroom workshop presented here was developed to improve student understanding of quantitative physiology by a set of question-guided simulations. Simulations are run on Chemostatus, a specially developed MATLAB-based program, which visualizes key parameters of simulated chemostat cultures as they proceed from dynamic growth conditions to steady state. In practice, the workshop stimulated active discussion between students and with their teachers. Moreover, its introduction coincided with increased average exam scores for questions on quantitative microbial physiology. The workshop can be easily implemented in formal microbial physiology courses or used by individuals seeking to test and improve their understanding of quantitative microbial physiology and/or chemostat cultivation.

A new teaching assistant model was adopted and qualitatively assessed for the general chemistry laboratory, in which both an undergraduate and a graduate teaching assistant provided instruction to students during the lab. Verbal interactions between graduate and undergraduate teaching assistants were recorded, transcribed, and coded using the modified Laboratory Observation Protocol for Undergraduate STEM (LOPUS). The codes were applied to capture how discussions, questioning, and explanations were conducted. In addition, the content discussed was coded to identify specific areas that pose challenges for students. Sizable differences were not observed between the number of interactions of the initiation, explanation, and questioning codes between graduate and undergraduate teaching assistants. Of the interactions, 77% focused on questions and discussions regarding the experimental setup. Discussions on the implications with regards to the effective use of undergraduate and graduate teaching assistants in chemistry laboratories are included.

Climate warming may lead to changes in the trophic structure and diversity of shallow lakes as a combined effect of increased temperature and salinity and likely increased strength of trophic interactions. We investigated the potential effects of temperature, salinity and fish on the plant-associated macroinvertebrate community by introducing artificial plants in eight comparable shallow brackish lakes located in two climatic regions of contrasting temperature: cold-temperate and Mediterranean. In both regions, lakes covered a salinity gradient from freshwater to oligohaline waters. We undertook day and night-time sampling of macroinvertebrates associated with the artificial plants and fish and free-swimming macroinvertebrate predators within artificial plants and in pelagic areas. Our results showed marked differences in the trophic structure between cold and warm shallow lakes. Plant-associated macroinvertebrates and free-swimming macroinvertebrate predators were more abundant and the communities richer in species in the cold compared to the warm climate, most probably as a result of differences in fish predation pressure. Submerged plants in warm brackish lakes did not seem to counteract the effect of fish predation on macroinvertebrates to the same extent as in temperate freshwater lakes, since small fish were abundant and tended to aggregate within the macrophytes. The richness and abundance of most plant-associated macroinvertebrate taxa decreased with salinity. Despite the lower densities of plant-associated macroinvertebrates in the Mediterranean lakes, periphyton biomass was lower than in cold temperate systems, a fact that was mainly attributed to grazing and disturbance by fish. Our results suggest that, if the current process of warming entails higher chances of shallow lakes becoming warmer and more saline, climatic change may result in a decrease in macroinvertebrate species richness and abundance in shallow lakes.

RESUMEN: Estas "observaciones" pretenden llamar la atención acerca de una serie de peculiaridades, sobre todo formales, que pueden observarse en el tenor actual del texto legal. Estas peculiaridades avalan la hipótesis de que en el texto de la lex Ursonensis cabe diferenciar varios estratos, procedentes de sucesivos momentos cronológicos, una hipótesis sólo esbozada en el presente trabajo.ABSTRACT: Some mainly formal peculiarities of the lex coloniae Genetivae luliae allow to distinguish different layers of its text.This paper is a first approach to the study of the composition of that Isw.

Las lagunas costeras de Aiguamolls de lEmpordà presentan una hidrología característica de los humedales mediterráneos. A los episodios de inundación, súbitos e irregulares en el tiempo, le siguen largos períodos de confinamiento en los que no hay entradas de agua y las lagunas tienden a la desecación. Durante el confinamiento en estas lagunas aumenta la salinidad, se acumula fósforo y se producen pérdidas de nitrógeno por desnitrificación, de manera que el nitrógeno limita la producción primaria. La comunidad acuática está formada por especies eurihalinas, que toleran las frecuentes fluctuaciones de salinidad, y su estructura no sigue ningún patrón estacional, sino que responde a la irregularidad hidrológica. Así, las diferentes especies aparecen cuando se producen las situaciones hídricas que les son propicias.

Boron, the element which is in close proximity with carbon in the periodic table has been hypothesized to produce diverse two‐dimensional structures that differ from well‐studied 2D materials. Icosahedron B12$$ {\mathcal{B}}_{12} $$, the monomers of which form the crystalline boron structure, appears as a recurring pattern in the chemistry of boron compounds, elemental boron and boron‐rich materials, functions as a building block in a majority of boron allotropes. The topological study of the icosahedral sheets is a necessary field to be investigated for the effective analysis and characterization of its physico‐chemical attributes without undertaking time‐consuming experimental research. The topological descriptors being expressed as numerical values enable scientists to compare and correlate data, which can be applied to quantitative structure‐activity relationships and quantitative structure‐property relationships modeling. In this study, various degree based molecular descriptors of the crystal boron icosahedral α$$ \alpha $$ sheet Bα(a,b)$$ {\mathcal{B}}_{\alpha}\left(\mathfrak{a},\mathfrak{b}\right) $$ has been formulated from a two‐dimensional lattice perspective using the 필‐polynomial approach. To establish the significance of these descriptors in the study of chemical attributes, an efficient linear regression modeling has also been performed, enabling the prediction of properties of several other boron sheets. [ABSTRACT FROM AUTHOR]