Search results for "feature"
showing 10 items of 4091 documents
Photografted fluoropolymers as novel chromatographic supports for polymeric monolithic stationary phases
2018
[EN] In this study, porous polymer monoliths were in situ synthesized in fluoropolymers tubing to prepare microbore HPLC columns. To ensure the formation of robust homogeneous polymer monoliths in these housing supports, the inner surface of fluoropolymer tubing was modified in a two-step photografting process. Raman spectroscopy and scanning electron microscopy (SEM) confirmed the successful modification of the inner poly(ethylene-co-tetrafluoroethylene) (ETFE) wall and the subsequent attachment of a monolith onto the wall. Poly(glycidyl methacrylate-co-divinylbenzene), poly(butyl methacrylate-co-ethyleneglycol dimethacrylate) and poly(styrene-co-divinylbenzene) monoliths were in situ synt…
The low-latitude monsoon climate during Dansgaard–Oeschger cycles and Heinrich Events
2000
During the last 100,000 years Dansgaard–Oeschger cycles (D/O cycles) and Heinrich Events have been the dominant signal of past climate variability over Greenland and the North Atlantic. The succession of stadials (cold) and interstadials (warm) associated with these cycles has been documented in records from the entire northern hemisphere, South America, New Zealand, Antarctica, the South Atlantic and the Southern Ocean. Evidently, climate forcing in the D/O band affects both hemispheres. The origin and cause of these teleconnected patterns is still unknown, even if a large proportion of the cooling in Europe and northern Asia during Heinrich Events is a meteorological response to cold surf…
Climate variations of Central Asia on orbital to millennial timescales
2016
AbstractThe extent to which climate variability in Central Asia is causally linked to large-scale changes in the Asian monsoon on varying timescales remains a longstanding question. Here we present precisely dated high-resolution speleothem oxygen-carbon isotope and trace element records of Central Asia’s hydroclimate variability from Tonnel’naya cave, Uzbekistan and Kesang cave, western China. On orbital timescales, the supra-regional climate variance, inferred from our oxygen isotope records, exhibits a precessional rhythm, punctuated by millennial-scale abrupt climate events, suggesting a close coupling with the Asian monsoon. However, the local hydroclimatic variability at both cave sit…
Nile Basin Climates
2009
The climate of the Nile Basin is characterised by a strong latitudinal wetness gradient. Whereas the areas north of 18°N remain dry most of the year, to the south there is a gradual increase of monsoon precipitation amounts. Rainfall regimes can be divided into 9 types, among which summer peak regimes dominate. In the southern half of the basin, mesoscale circulation features and associated contrasts in local precipitation patterns develop as a result of a complex interplay involving topography, lakes and swamps. Precipitation changes and variability show up as 3 distinct modes of variability. Drying trends since the 1950s are found in central Sudan and to some extent the Ethiopian Highland…
A new species of Ferula (Apiaceae) from Malta
2018
Ferula melitensis, a new species from the Malta Archipelago, is described and illustrated. It belongs to the taxonomic group of F. communis, showing close relationships mainly with F. tunetana, F. arrigonii, F. communis s.str. and F. glauca, from which it differs in several features regarding the stem, leaves (mainly for shape and size of terminal segments), flowers and mericarps; other significant differences regard the ecology and phenology. The investigations, carried out on living plants, herbarium material and literature data, regard the morphological analysis of vegetative and reproductive structures, the anatomy of terminal leaf segments and mericarps, as well as the shape and size o…
Ensemble Averaging and Multiple Statistical Testing of EMG Activities of Cyclically Repeated Body Motions. A Tool for Muscle Function Analysis in Exp…
2003
Coupled with suitable computerized signal recording and processing methods surface electromyography can be a powerful tool for the analysis of muscle activity in specific body movements. It can be used for this purpose in experimental and in clinical diagnostic orthopaedics as well as in physiotherapy. We describe in this paper a motion analysis system comprising this feature. It has been employed for the diagnosis of the basic angular kinematics and muscle function in human gait and other cyclically repeatable movements of the human locomotive system. Changes in the temporal characteristics of the movements and the muscle activity due to changed physical or experimental conditions can be s…
Students' school performance, task-focus, and situation-specific motivation
2015
Going beyond studies of individual differences in and profiles of students' motivation, we investigated situation-specific (intra-personal) experiences of autonomous (enjoyment, interest, and task choice) and controlled (having to do, and the teacher wanting them to do a task) motivation across learning situations during one week, and how these were related to student characteristics (teacher rated academic performance and task-focus). Three-hundred and fourteen primary school students (Years 5 and 6) completed electronic questionnaires on Personal Digital Assistants, on an average of 11.2 learning episodes during a week. Multilevel Structural Equation Models provided support for a model ba…
Does fragmentation of wetlands affect gene flow in sympatric Acrocephalus warblers with different migration strategies?
2015
Wetlands are naturally patchy habitats, but patchiness has been accentuated by the extensive wetlands loss due to human activities. In such a fragmented habitat, dispersal ability is especially important to maintain gene flow between populations. Here we studied population structure, genetic diversity and demographic history of Iberian and North African populations of two wetland passerines, the Eurasian reed warbler Acrocephalus scirpaceus and the moustached warbler Acrocephalus melanopogon. These species are closely related and sympatric in our study sites, but the reed warbler is a long-distance migrant and widespread bird while the moustached warbler is resident or migrates over short d…
Design and Implementation of a Low-cost Embedded Iris Recognition System on a Dual-core Processor Platform
2012
Abstract Design of a low-cost embedded iris recognition system is described in this paper. Firstly, we develop a simple and effective iris image acquisition unit, which is cheap and easy to use. This is achieved by both of hardware design and image evaluation algorithm development. Secondly, the iris recognition algorithm is introduced, including iris segmentation, image normalization, feature extraction, and code matching. The algorithm implementation architecture is based on an embedded dual-core processor platform, Texas Instruments TMS320DM6446 evaluation module (Davinci), which contains an ARM core and a DSP core in one chip. Thirdly, the evaluation experiments are performed on the est…
A comprehensive survey of multi-view video summarization
2021
[EN] There has been an exponential growth in the amount of visual data on a daily basis acquired from single or multi-view surveillance camera networks. This massive amount of data requires efficient mechanisms such as video summarization to ensure that only significant data are reported and the redundancy is reduced. Multi-view video summarization (MVS) is a less redundant and more concise way of providing information from the video content of all the cameras in the form of either keyframes or video segments. This paper presents an overview of the existing strategies proposed for MVS, including their advantages and drawbacks. Our survey covers the genericsteps in MVS, such as the pre-proce…