Search results for "Micromorph"
showing 10 items of 25 documents
Two-dimensional apparent microfabric of the basal Late Weichselian till and associated shear zone: case study from western Latvia
2008
The examination of glacial sediments in thin sections has become a common procedure in recent years. Apparent sand grain orientation (microfabric) in thin sections is one of the key elements marking certain microstructures. In an attempt to make till micromorphology studies less subjective and investigate the orientation of sand-sized particles in tills, we have developed an image analysis procedure to measure and analyse the spatial distribution of the till microfabric. We studied 13 thin sections of the Weichselian subglacial till and basal shear zone outcropping in the Baltic Sea bluffs at the Ziemupe site in western Latvia. The results were visualized as a two-dimensional grid of rose d…
Plant morphology: outdated or advanced discipline in modern plant sciences?
2018
Despite an increasing societal awareness and sensitivity about biological diversity and nature conservation as pivotal matters for human survival and well-being, plant systematics has gone through a steady decline in interest, and researches on these topics are often neglected. This particularly applies to plant morphology in its broad sense (i.e. including anatomy, histology, micro-morphology), which has increasingly become marginalized and considered less important than other scientific methods in plant biology. Notwithstanding, even in the current times of genomics (plus other “omics” topics) and functional ecology, when trait-based approaches are essential for studying and understanding…
Flower and fruit structure of the endangered species Petagnaea gussonei (Sprengel) Rauschert (Saniculoideae, Apiaceae) and implications for its repro…
2015
Petagnaea gussonei (Apiaceae) is an endangered species endemic to the Nebrodi mountains (north-eastern Sicily). Although an increasing number of studies have been performed on this species, its reproductive biology remains poorly understood. The aim of this study was to investigate in detail the structure of the flower and the fruit of Petagnaea, and the possible implications for its breeding system and seed dispersal mechanism. Results from fieldwork, light microscopy and scanning electron microscopy suggest (1) the presence of protandrous hermaphrodite flowers; (2) geitonogamy, autogamy, and allogamy as breeding system mechanisms of P. gussonei, even if asexual reproduction is preferred b…
Plant morphology: outdated or advanced discipline in modern plant sciences?
2019
In the last decades, with the increase of molecular studies, the study of plant forms has gone through a steady decline in interest, and researches on this topic are often neglected and underestimated. Notwithstanding, comparative morphology as integrative discipline still assumes a pivotal role in modern sciences, remaining fundamentally relevant to nearly all fields of plant biology, such as systematics, evolutionary biology, ecology, physiology, genetics, molecular biology, not to mention also agriculture, bioengineering, and forensic botany. Contrary to common belief, plant morphology is not a conservative finished science, but, like other sciences, it is open to constant innovations in…
First data on the taxonomic diversity of the Portulaca oleracea aggregate (Portulacaceae) in Iran
2017
The review of specimens from Iran belonging to the Portulaca oleracea L. aggregate resulted in the recognition of six microspecies: P. cypria Danin, P. granulatostellulata (Poelln.) Ricceri & Arrigoni, P. nitida (Danin & H.G.Baker) Ricceri & Arrigoni, P. rausii Danin, P. socotrana Domina & Raimondo, and P. trituberculata Danin, Domina & Raimondo, all reported for the first time for the flora of Iran. The identification was based on the microscopic study of seeds. It is noted that P. oleracea is not confirmed for Iran. Distribution data and an identification key for Portulaca microspecies in Iran are presented.
3D photonic crystal intermediate reflector for micromorph thin-film tandem solar cell
2008
The concept of 3D photonic intermediate reflectors for micromorph silicon tandem solar cells has been investigated. In thin-film silicon tandem solar cells consisting of amorphous and microcrystalline silicon with two junctions of a-Si/μc-Si, efficiency enhancements can be achieved by increasing the current density in the a-Si top cell. It is one goal to provide an optimized current matching at high current densities. For an ideal photon-management between top and bottom cell, a spectrally selective intermediate reflective layer (IRL) is necessary, which is less dependent of the angle of incidence than state-of-the-art thickness dependent massive interlayers. The design, preparation and cha…
The role of pedogenic overprinting in the obliteration of parent material in some polygenetic landscapes of Sicily (Italy)
2016
Abstract Many soils older than the Holocene have experienced several changes, and possess properties that may be due to the complex effect of several stages of soil development; these soils are called polygenetic. It is still rather unclear, however, if, as time elapses, pedogenic processes tend to diverge generating different soils, or converge towards increasingly similar soils. We studied five pedons (37°60′N, 13°90′E) exposed to present weathering simultaneously since the Holocene but located on Upper Miocene or Holocene parent material. Their XRD and FTIR clay mineralogy reveal an overall homogeneity; smectites, calcite and gypsum reach the thermodynamic equilibrium, a slight undersatu…
Le site Age-du-fer du Gros-Buisson à Villiers-sur-Seine (77), de l’intrasite au bassin moyen de la Seine : réflexions sur la place de la géoarchéolog…
2018
International audience
Saint-Venant (62), rue de Guarbecque : des enclos funéraires de l'âge du Bronze : rapport de fouilles
2015
Cette fouille a permis de dégager un ensemble de trois cercles, dont un double, cinq incinérations parmi lesquelles deux semblent contemporaines d'un des enclos circulaires et deux réseaux de fossés qui traversent l'emprise de part en part en recoupant les cercles. L'occupation initiale est composé d'un double cercle d'un diamètre externe de 22 m. Il se compose d'un fossé externe d'environ 60 cm de large pour une profondeur de 50 cm et d'un second, plus imposant, dont l'ouverture peut atteindre 1,60 m de large pour une profondeur d'1 m. Ils sont distants de deux mètres. Deux grandes phases de comblement sont clairement distinctes, on signalera toutefois une complexité stratigraphique beauco…
Photonic crystal intermediate reflector in micromorph tandem solar cells
2011
Experimental and numerical evidences are presented which show that the efficiency of silicon based tandem solar-cells can be increased by incorporating a three-dimensional photonic crystal as an intermediate reflector.