Turbulence-mediated facilitation of resource uptake in patchy stream macrophytes

Many landscapes are characterized by a patchy, rather than homogeneous, distribution of vegetation. Often this patchiness is composed of single-species patches with contrasting traits, interacting with each other. To date, it is unknown whether patches of different species affect each other’s uptake of resources by altering hydrodynamic conditions, and how this depends on their spatial patch configuration. Patches of two contrasting aquatic macrophyte species (i.e., dense canopy-forming Callitriche and sparse canopy-forming Groenlandia) were grown together in a racetrack flume and placed in different patch configurations. We measured 15NH4+ uptake rates and hydrodynamic properties along the centerline and the lateral edge of both patches. When the species with a taller, denser canopy (Callitriche) was located upstream of the shorter, sparser species (Groenlandia), it generated turbulence in its wake that enhanced nutrient uptake for the sparser Groenlandia. At the same time, Callitriche benefited from being located at a leading edge where it was exposed to higher mean velocity, as its canopy was too dense for turbulence to penetrate from upstream. Consistent with this, we found that ammonium uptake rates depended on turbulence level for the sparse Groenlandia and on mean flow velocity for the dense Callitriche, but Total Kinetic Energy was the best descriptor of uptake rates for both species. By influencing turbulence, macrophyte species interact with each other through facilitation of resource uptake. Hence, heterogeneity due to multi-specific spatial patchiness has crucial implications for both species interactions and aquatic ecosystem functions, such as nitrogen retention

Nuclear architecture organized by Rif1 underpins the replication-timing program

DNA replication is temporally and spatially organized in all eukaryotes, yet the molecular control and biological function of the replication-timing program are unclear. Rif1 is required for normal genome-wide regulation of replication timing, but its molecular function is poorly understood. Here we show that in mouse embryonic stem cells, Rif1 coats late-replicating domains and, with Lamin B1, identifies most of the late-replicating genome. Rif1 is an essential determinant of replication timing of non-Lamin B1-bound late domains. We further demonstrate that Rif1 defines and restricts the interactions between replication-timing domains during the G1 phase, thereby revealing a function of Rif1 as organizer of nuclear architecture. Rif1 loss affects both number and replication-timing specificity of the interactions between replication-timing domains. In addition, during the S phase, Rif1 ensures that replication of interacting domains is temporally coordinated. In summary, our study identifies Rif1 as the molecular link between nuclear architecture and replication-timing establishment in mammals

How to build vegetation patches in hydraulic studies: a hydrodynamic-ecological perspective on a biological object

Vegetation in freshwater and coastal ecosystems modifies flows, retains sediment, protects banks and shorelines from erosion. Hydraulic laboratory studies with live vegetation or artificial plant mimics, or numerical models with abstracted patches, are often used to quantify the effects of vegetation on water flow and sedimentation. However, the choice of plant and patch characteristics is often not supported by field observations of patch dimensions, density or spacing between consecutive patches. The discrepancy between plants in natural conditions and in flume experiments or numerical studies may affect the relevance of these findings for natural ecosystems. In this study, we provide guidelines for building realistic vegetation patches in hydraulic studies. We collected data on four species of fully submerged freshwater aquatic macrophytes that can grow into well-defined patches. We considered three relevant levels: individual plants (inside patches), isolated patches and multiple neighbouring patches. At the plant level, we observed significant differences in biomechanical traits (Young’s modulus, flexural stiffness), resulting in stem Cauchy numbers ranging from 85.25 to 325.84, and leaf Cauchy numbers from 163.81 to 2003.97. At the patch level, we found significant relationships between patch length, width and height, showing covariation among different patch characteristics. The relationships among patch dimensions differed significantly among sampling sites for three of the four species, suggesting high intraspecific variability in patch sizes. By providing a first set of guidelines for choosing correct and ecologically relevant plant characteristics, this dataset aims to improve our understanding of the complex processes occurring inside and around submerged vegetated patches

EARLINET dust observations vs. BSC-DREAM8b modeled profiles: 12-year-long systematic comparison at Potenza, Italy

In this paper, we report the first systematic comparison of 12-year modeled dust extinction profiles vs. Raman lidar measurements. We use the BSC-DREAM8b model, one of the most widely used dust regional models in the Mediterranean, and Potenza EARLINET lidar profiles for Saharan dust cases, the largest one-site database of dust extinction profiles. A total of 310 dust cases were compared for the May 2000-July 2012 period. The model reconstructs the measured layers well: profiles are correlated within 5% of significance for 60% of the cases and the dust layer center of mass as measured by lidar and modeled by BSC-DREAM8b differ on average 0.3 +/- 1.0 km. Events with a dust optical depth lower than 0.1 account for 70% of uncorrelated profiles. Although there is good agreement in terms of profile shape and the order of magnitude of extinction values, the model overestimates the occurrence of dust layer top above 10 km. Comparison with extinction profiles measured by the Raman lidar shows that BSC-DREAM8b typically underestimates the dust extinction coefficient, in particular below 3 km. Lowest model-observation differences (below 17 %) correspond to a lidar ratio at 532 nm and Angstrom exponent at 355/532 nm of 60 +/- 13 and 0.1 +/- 0.6 sr, respectively. These are in agreement with values typically observed and modeled for pure desert dust. However, the highest differences (higher than 85 %) are typically related to greater ngstr m values (0.5 +/- 0.6), denoting smaller particles. All these aspects indicate that the level of agreement decreases with an increase in mixing/modification processes

Data presented in the paper “Flow-divergence feedbacks control propagule retention by in-stream vegetation: the importance of spatial patterns for facilitation”

The research objective was to investigate the main factors affecting the ability of patches of the submerged macrophyte Callitriche platycarpa to influence the dispersal of other aquatic plant species, by trapping vegetative fragments. Hence, we tested the role of propagule traits, spatial patch configuration and hydrodynamic forcing on the number of fragments trapped in a flume laboratory experiment. Moreover, we tested the role of submerged vegetation cover and structure on fragment retention through a field release experiment. The data include a 4-week mesocosm monitoring of vegetative fragment buoyancy, and the number of fragments trapped by submerged vegetation in both flume and field releases

Data presented in the paper "Landscapes of facilitation: how self-organized patchiness of aquatic macrophytes promotes diversity in streams"

This dataset contains the experimental data and modelling presented in the paper “Landscapes of facilitation: how self-organized patchiness of aquatic macrophytes promotes diversity in streams”, with the above contributors as authors, published in Ecology. The dataset contains the underlying data (model outputs, field data) and scripts (for model and aerial picture analyses) presented in the manuscript

Data presented in the paper "Landscapes of facilitation: how self-organized patchiness of aquatic macrophytes promotes diversity in streams"

This dataset contains the experimental data and modelling presented in the paper “Landscapes of facilitation: how self-organized patchiness of aquatic macrophytes promotes diversity in streams”, with the above contributors as authors, published in Ecology. The dataset contains the underlying data (model outputs, field data) and scripts (for model and aerial picture analyses) presented in the manuscript

Preventive versus curative photobiomodulation for oral mucositis in patients with multiple myeloma undergoing hematopoietic stem cell transplantation: which approach is more effective?

Purpose: There is increasing evidence that photobiomodulation (PBM) therapy is both an effective and safe approach in hematopoietic stem cell transplantation (HSCT) for both prevention and management of oral mucositis (OM), but its use in clinical practice is still limited and the timing of application is under discussion. The aim of this retrospective study was to evaluate possible differences between patients treated either with preventive or curative PBM therapy. Methods: The retrospective case series included 24 patients suffering from multiple myeloma who underwent the same conditioning and transplantation protocol. Patients were treated either with preventive PBM starting from the first day of conditioning up to two days post-HSCT or with curative PBM (starting at OM onset for four consecutive days). OM score, pain, and functional parameters were recorded. Results: All patients developed OM. Preventive PBM was significantly more effective in reducing OM severity (p < 0.0001) and pain (p < 0.0001) post-HSCT than curative PBM. Furthermore, we found a lower number of patients reporting discomfort in all subjective parameters (pain during swallowing, chewing, and speaking) in the preventive PBM group. No adverse events related to PBM therapy were recorded in both groups. Conclusion: The timing for PBM therapy in patients undergoing HSCT is crucial: when started on the first day of conditioning, it significantly reduces both pain and OM severity, providing an important benefit also in subjective oral functions such as speaking, swallowing, and chewing, thus increasing the overall adherence to the oncological therapies

Occupational Exposure Assessment to Antineoplastic Drugs in Nine Italian Hospital Centers over a 5-Year Survey Program

In the present study, surface contamination where antineoplastic drugs (ADs) are present was investigated, as occupational exposure risk is still an open debate. Despite recommendations and safety standard procedures being in place in health care settings, quantifiable levels of ADs are being reported in the recent literature. Thus, a survey monitoring program was conducted over five years (2016&ndash;2021) in nine Italian hospitals. The repeated surveys produced 8288 data points that have been grouped according to the main hospital settings, such as pharmacy areas and patient care units. Based on the most often prepared ADs, the investigated drugs were cyclophosphamide (CP), gemcitabine (GEM), 5-fluorouracil (5&ndash;FU), and platinum compounds (Pt). Patient care units had a frequency of positive wipe samples (59%) higher than pharmacies (44%). Conversely, pharmacies had a frequency of positive pad samples higher (24%) than patient care units (10%). Moreover, by statistical analysis, pad samples had a significantly higher risk of contamination in pharmacy areas than in patient care units. In this study, the 75th and the 90th percentiles of the contamination levels were obtained. The 90th percentile was chosen to describe a suitable benchmark that compares results obtained by the present research with those previously reported in the literature. Based upon surface contamination loads, our data showed that 5&ndash;FU had the highest concentration values, but the lowest frequency of positive samples. In pharmacy areas, the 90th percentile of 5&ndash;FU data distribution was less than 0.346 ng/cm2 and less than 0.443 ng/cm2 in patient care units. AD levels are higher than those reported for health care settings in other European countries yet trends of contamination in Italy have shown to decrease over time