Search results for "OTU"

Data from: Effects of undergrowth removal and edge proximity on ground beetles and vascular plants in urban boreal forests

2019

Urban forests are regularly managed for human safety and aesthetic reasons, but they are crucial habitat for many species. Removals of undergrowth occur commonly in these forests, yet the ecological consequences of these operations are poorly understood. We sampled ground beetles (Coleoptera, Carabidae) and vascular plants along 20-m edge gradients in Finnish urban forests, in five stands treated 0.5−2.5 years earlier with undergrowth removal and in five untreated stands. We hypothesized that undergrowth removal and edge proximity would benefit opportunistic and open-habitat species, whereas shady-habitat species would be affected negatively. (1) Regarding carabids, diversity and evenness i…

Effect of TiO2 and Al2O3 Addition on the Performance of Chitosan/Phosphotungstic Composite Membranes for Direct Methanol Fuel Cells

2023

Composite chitosan/phosphotungstic acid (CS/PTA) with the addition of TiO2 and Al2O3 particles were synthesized to be used as proton exchange membranes in direct methanol fuel cells (DMFCs). The influence of fillers was assessed through X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, liquid uptake, ion exchange capacity and methanol permeability measurements. The addition of TiO2 particles into proton exchange membranes led to an increase in crystallinity and a decrease in liquid uptake and methanol permeability with respect to pristine CS/PTA membranes, whilst the effect of the introduction of Al2O3 particles on the characteristics of membranes is almost the op…

Selective recovery of phosphorus as AlPO4 from silicon-free CFB-derived fly ash leachate

2018

The prospect of phosphorus (P) recovery from siliceous fly ash was investigated. The phosphorus content in the pristine fly ash was 1.21%. Obtaining pure phosphorus products from fly ash is very challenging because of high concentration of other elements, silicon (Si) at 17.3% being the major contaminant. The fly ash was fractionated with sieve size of 125 μm to concentrate the phosphorus in the small-size fraction, which also facilitated the removal of 78% of silica (Si) in the solid phase. The fractionated fly ash was treated with 8 M HCl in order to remove 98% of Si by aging (5 h) of leachate until precipitation of Si-gel, and a phosphorus-rich solution is obtained. Iron (Fe) is also con…

Characterization of the Teeth Skeletal Matrix from <i>Arbacia lixula</i>

2016

The teeth of sea urchins are highly complex composite structures, composed predominantly of high magnesium calcite, and of a minor heterogeneous assemblage of organic macromolecules that are occluded within the mineral. The organic matrix fulfils important functions in mineralization, in addition to giving the mineral phase peculiar mechanical properties, different from that of purely inorganic calcite. Nevertheless, the composition and function of individual components of the organic matrix still remains largely unknown. Up to now, the detailed protein repertoire of teeth from a single sea urchin species (Strongylocentrotus purpuratus, order Camarodonta) was investigated. In this study, we…

Vēsture: Latvijas Universitātes Žurnāls, 2018, Nr.6

2019

Nanochlorum eucaryotum — a green enigmatic alga: morphology, biochemistry and molecular biology

1994

In search of a natural systematic locality for algae — and also for other organisms — quite regularly the central question of evolution comes up. This proves as especially pertinent, when the taxonomic position of the most original phytoflagellates has to be considered. In the classical view of the direct filiation theory the ancestral phytoflagellata is positioned at the verge of the prokaryotic to the eukaryotic stage.

Electrophoretic study on two morphologically distinguishable populations of Paracentrotus lividus (Echinodermata) from distinct areas of the mediterr…

1998

‘How this holiday makes a difference’: The language of environment and the environment of nature in a cross-cultural study of ecotourism

2010

Partendo dal presupposto che le differenze culturali spesso costituiscono una fonte potenziale di problematiche traduttive, questo contributo mira a evidenziare le differenze che emergono sul piano linguistico, a livello lessicale, ma soprattutto fraseologico, in seguito a variegati orientamenti culturali che agiscono come filtri. Il linguaggio specialistico analizzato riguarda una nicchia particolare del mercato del turismo, ossia l’ecoturismo, che sta conquistando un terreno sempre più vasto in seguito ad una maggiore attenzione rivolta nei confronti di tematiche attuali, come quelle di impatto ambientale. Abbracciando una prospettiva interculturale, il lavoro indaga il diverso approccio …

Selective adsorption of oppositely charged PNIPAAM on halloysite surfaces: a route to thermo-responsive nanocarriers.

2018

Halloysite nanotubes were functionalized with stimuli-responsive macromolecules to generate smart nanohybrids. Poly(N-isopropylacrylamide)-co-methacrylic acid (PNIPAAM-co-MA) was selectively adsorbed into halloysite lumen by exploiting electrostatic interactions. Amine-terminated PNIPAAM polymer was also investigated that selectively interacts with the outer surface of the nanotubes. The adsorption site has a profound effect on the thermodynamic behavior and therefore temperature responsive features of the hybrid material. The drug release kinetics was investigated by using diclofenac as a non-steroidal anti-inflammatory drug model. The release kinetics depends on the nanoarchitecture of th…

Amorphous Silicon Nanotubes via Galvanic Displacement Deposition

2013

Amorphous silicon nanotubes were grown in a single step into a polycarbonate membrane by a galvanic displacement reaction conducted in aqueous solution. In order to optimize the process, a specifically designed galvanic cell was used. SEM images, after polycarbonate dissolution, showed interconnected nanotube bundles with an average length of 18 μm and wall thickness of 38 nm.The deposited silicon was revealed by EDS analysis, whilst X-ray diffraction and Raman spectroscopy showed that nanotubes have an amorphous structure. Silicon nanotubes were also characterized by photo-electrochemical measurements that showed n-type conductivity and optical gap of ~1.6 eV. Keywords: Silicon nanotubes, …