Search results for "OLDS"

Testing a theoretical resistance law for overland flow on a stony hillslope

2020

Overland flow, sediments, and nutrients transported in runoff are important processes involved in soil erosion and water pollution. Modelling transport of sediments and chemicals requires accurate estimates of hydraulic resistance, which is one of the key variables characterizing runoff water depth and velocity. In this paper, a new theoretical power–velocity profile, originally deduced neglecting the impact effect of rainfall, was initially modified for taking into account the effect of rainfall intensity. Then a theoretical flow resistance law was obtained by integration of the new flow velocity distribution. This flow resistance law was tested using field measurements by Nearing for the …

2019

Abstract. The flow of fluids through porous media such as groundwater flow or magma migration is a key process in geological sciences. Flow is controlled by the permeability of the rock; thus, an accurate determination and prediction of its value is of crucial importance. For this reason, permeability has been measured across different scales. As laboratory measurements exhibit a range of limitations, the numerical prediction of permeability at conditions where laboratory experiments struggle has become an important method to complement laboratory approaches. At high resolutions, this prediction becomes computationally very expensive, which makes it crucial to develop methods that maximize …

Improvement of osteogenic differentiation of human mesenchymal stem cells on composite poly l-lactic acid/nano-hydroxyapatite scaffolds for bone defe…

2020

Tissue engineering offers new approaches to repair bone defects, which cannot be repaired physiologically, developing scaffolds that mimic bone tissue architecture. Furthermore, biomechanical stimulation induced by bioreactor, provides biomechanical cues that regulate a wide range of cellular events especially required for cellular differentiation and function. The improvement of human mesenchymal stem cells (hMSCs) colonization in poly-L-lactic-acid (PLLA)/nano- hydroxyapatite (nHA) composite scaffold was evaluated in terms of cell proliferation (dsDNA content), bone differen- tiation (gene expression and protein synthesis) and ultrastructural analysis by comparing static (s3D) and dynamic…

Ventilation and gas exchange before and after voluntary static surface breath-holds in clinically healthy bottlenose dolphins, Tursiops truncatus

2019

ABSTRACT We measured respiratory flow ( V ), breathing frequency ( f R ), tidal volume ( V T ), breath duration and end-expired O 2 content in bottlenose dolphins ( Tursiops truncatus ) before and after static surface breath-holds ranging from 34 to 292 s. There was considerable variation in the end-expired O 2 , V T and f R following a breath-hold. The analysis suggests that the dolphins attempt to minimize recovery following a dive by altering V T and f R to rapidly replenish the O 2 stores. For the first breath following a surface breath-hold, the end-expired O 2 decreased with dive duration, while V T and f R increased. Throughout the recovery period, end-expired O 2 increased while the…

Hydrogel‐Based 3D Bioprinting for Bone and Cartilage Tissue Engineering

2020

As a milestone in soft and hard tissue engineering, a precise control over the micropatterns of scaffolds has lightened new opportunities for the recapitulation of native body organs through three dimentional (3D) bioprinting approaches. Well-printable bioinks are prerequisites for the bioprinting of tissues/organs where hydrogels play a critical role. Despite the outstanding developments in 3D engineered microstructures, current printer devices suffer from the risk of exposing loaded living agents to mechanical (nozzle-based) and thermal (nozzle-free) stresses. Thus, tuning the rheological, physical, and mechanical properties of hydrogels is a promising solution to address these issues. Th…

New, old and evergreen frontiers in freshwater phytoplankton ecology: the legacy of Colin S. Reynolds

2020

This paper offers a brief overview of the contributions provided by widely recognised phytoplankton ecologists to honour the memory of an undisputed leader in the field of aquatic sciences: Colin S. Reynolds. Colin passed away quite unexpectedly in December 2018 causing a wave of sorrow that rapidly circulated among friends and colleagues all over the world. The 14 review papers collected in this Special Issue form a tribute to Colin’s scientific thinking, which survives the man and represents a legacy to all the scientists in the field, especially to young generations. Although authors and editors carefully selected 14 different topics, a certain degree of overlap exists among the collecte…

Larger cell or colony size in winter, smaller in summer – a pattern shared by many species of Lake Kinneret phytoplankton

2017

We examined an 8.5-year record (2004-2012) of cell size data for phytoplankton species from Lake Kinneret, Israel, sampled weekly or at 2-week intervals and determined microscopically by the same person. Many of the species abundant enough to be counted year-round showed a typical seasonal cell size pattern that repeated annually: cell diameter was maximal in winter and minimal in summer. This pattern was shared by species from different taxonomic groups including cyanobacteria, chlorophyta, and dinoflagellates. Similarly, in colonial species of diatoms, chlorophyta, and cyanobacteria the number of cells per colony was larger in winter and smaller in summer. We postulated that the seasonal …

Phytoplankton and its biotic interactions: Colin Reynolds’ legacy to phytoplankton ecologists

2019

The 18th workshop of the International Association for Phytoplankton Taxonomy and Ecology (IAP), the first ‘‘tropical’’ IAP ever, the third one outside Europe, and the first one in South America, was held in Natal, Brazil, from August 27 to September 3, 2017, and its main ecological theme was the Phytoplankton and its biotic interactions. The taxonomic topic of the workshop was chosen based on function instead of phylogeny, and to link to the ecological theme of the workshop, the taxonomic theme was therefore centered on mixotrophic microalgae.

Inflorescence scents of Calendula maritima, C. suffruticosa subsp. fulgida, and their hybrid

2018

Premise of research. Hybridization is an important driver of plant evolutionary processes. By attracting the same pollinators to different species, floral scents may be involved in the formation of hybrids and breakdown of species boundaries. In contrast, by attracting a different suite of pollinators to hybrids and their parents, floral scents are believed to contribute to speciation processes initiated by hybridization events. Scents may or may not differ between the hybrids and their parents, but little is known about the scent chemistry of parental species and their hybrids. Methodology. We studied the inflorescence scents of parental Calendula maritima and C. suffruticosa subsp. fulgid…

Potential for managing life history diversity in a commercially exploited intermediate predator, the goldsinny wrasse (Ctenolabrus rupestris)

2019

Abstract Small-bodied wrasse species are important for structuring coastal marine ecosystems but are also increasingly harvested as parasite cleaners on farmed salmon. Identifying management regulations that will support long-term sustainability of wrasse fisheries is challenging, because there is still limited knowledge about the impacts of fisheries on the demography of these intermediate predators in their natural environments. To this end, we studied individual growth histories of goldsinny wrasse (Ctenolabrus rupestris) at a fine spatial scale across replicated marine protected areas (MPAs) and areas open to commercial harvesting on the Norwegian coast. The MPAs were established 1–7 ye…