10 research outputs found
Natuurtechnisch beheersplan voor de duinen van het militair domein 'Kwartier Lombardsijde' te Nieuwpoort
Ontwerp-ecosysteemvisie Kalkense Meersen en Berlare Broek: een verkenning van natuurpotenties
Feeding ecology of Konik horses and donkeys in Belgian coastal dunes and its implications for nature management
Foraging behaviour and diet selection of Koniks and donkeys were studied in order to estimate their possible impact on vegetation development and hence their appropriateness as nature management tools.Koniks show a larger intake rate and quantity than do donkeys. Koniks do not show significant seasonal differences in biomass intake, whereas donkeys consume significantly more in winter.Both animal species feed mainly on graminoids. The Konik diet is composed of 86 % of graminoids with an additional12 % of herbs. The donkey diet consists of 69 % of graminoids, which are mainly supplemented with browsing (18 %), e.g. twigs and leaves of Ligustrum vulgare and Rubus caesius. Calamagrostis epigejos, Rosa pimpinellifolia (fruits), Carex arenaria and Arrhenatherum elatius are the most important plant species eaten by donkeys (based on number of bites and biomass). Koniks eat Calamagrostis epigejos significantly more, qualitatively (number of bites) as well as quantitatively (biomass intake), than any other plant species, but Cirsium arvense, Calamagrostis canescens, Juncus subnodulosus, Holcus lanatus and Claytonia perfoliata are also frequently consumed.Koniks as well as donkeys do eat plant species that nature managers would like to see decline in dominance, e.g. Calamagrostis epigejos, but browsing on scrub species is insufficient to decrease the area occupied by shrubs
Clinical evaluation of the novel Capiox NX19 adult oxygenator-a multicenter study
Introduction The novel Capiox NX19 adult oxygenator is, compared to its predecessors, improved with enhanced air removal technology, a polymer heat exchanger and smaller, innovative hollow fibers resulting in a surface area reduction and a lower priming volume. The aim of this study was to evaluate the NX19 oxygenator performance in a clinical setting. Methods A prospective multicenter study was performed involving three large European university hospitals. The Capiox NX19 (n = 150) performance was assessed during adult cardiopulmonary bypass and involved gaseous microemboli handling and gas transfer efficiency. The heat exchanger performance was evaluated separately in vitro. Results The heat exchanger performance factors were 0.80 +/- 0.03 and 0.58 +/- 0.04 at pump flow rates of 3 L/min and 6 L/min, respectively. After priming, residual post-oxygenator gaseous microemboli count and volume were decreased by 91% and 93.7%, respectively. The gas compartment pressure was 6.0 +/- 2.5 mmHg, while the O-2 transfer was 69 +/- 30 mL/min/m(2) and the CO2 transfer 73 +/- 34 mL/min/m(2). The O-2 gradient was 44 +/- 19 mmHg/LPM and the O-2 diffusing capacity 0.38 +/- 0.14 mL/min/mmHg. The shunt fraction was 0.19 +/- 0.13, whereas oxygenator resistance and shear stress were 10.5 +/- 3.7 mmHg/LPM and 5.1 +/- 3.1 dyn/cm(2), respectively. Conclusion This multicenter study displayed good clinical safety and performance of the NX19 oxygenator
Naar een Geïntegreerd Watervoorzienings- en Natuurontwikkelingsplan (GWEN) voor de Westkust: gaan waterwinning en natuurontwikkeling hand in hand in overdekt waddenlandschap en Lenspolder?
Eliminative behaviour of free-ranging horses: do they show latrine behaviour or do they defecate where they graze?
In contrast to horses in pastures, it is thought that free-ranging horses do not perform latrine behaviour, i.e. a behavioural pattern whereby the animals graze and defecate in separate areas. However, few studies deal with this particular subject, reporting contrasting conclusions. We hypothesize that horses free-ranging in large heterogeneous areas do not perform latrine behaviour. Thus, we believe that grazing and elimination behaviour are spatially related: where horses graze, they will also defecate. Behavioural data were collected from Konik horses, Haflinger horses, Shetland ponies and donkeys, grazing in different nature reserves (54–80 ha). Data for the different equids were analyzed separately, as well as data for mares and stallions (Konik and donkey stallions only). We investigated the proportion of the number of defecations/urinations while grazing on the total number of defecations/urinations; furthermore, we searched for the sequence of behaviours representing latrine behaviour in the strict sense. Additionally, we analyzed the correlation between grazing behaviour and eliminative behaviour on both vegetation type level and patch level. All the female equids often continued grazing while defecating. During urination, grazing ceases in the majority of instances. Cases where a mare terminated grazing in a certain vegetation type and sward height to eliminate in another vegetation type or in another sward height within the same vegetation type were rarely observed. On the vegetation type level as well as on the patch level, there was a highly significant (Pr ranges between 0.553 and 0.955; in case of the urination variables r ranges between 0.370 and 0.839) illustrate that the spatial distribution of the eliminative behaviour can be explained to a high degree by the spatial distribution of the grazing behaviour. Results in the case of the stallions are preliminary, but indicate the same pattern. Horses, free-ranging in large heterogeneous areas, do not perform latrine behaviour, but defecate where they graze. Possibly, animal density is of major importance to explain this behavioural difference with horses in pastures. We suggest that also spatial vegetation heterogeneity and plant productivity of the grazed area, as well as parasite status of the grazing animals could play a role
AUTONOMOUS OPERATIONS OF A MICRO-ROVER FOR GEO-SCIENCE ON MARS
ABSTRACT. This paper describes the end-to-end control system used to program and supervise autonomous operations of a micro-rover placed on the Mars surface by a lander spacecraft. This rover, named Nanokhod, is characterised by an exceptionally high payload-mass/total-mass ratio. The Nanokhod weighs only about 3 kg but carries a payload of about 1.5 kg of scientific instruments. This is achieved by providing power to the rover from the lander through the tether rather than from energy sources on the rover. The tether also carries data and commands between the lander and the rover. To accomplish the required autonomy within the restrictions of the mission scenario, a novel end-toend control system has been designed, featuring a control station to program high-level commands for the lander-rover pair. These commands are uplinked to the space segment to be executed autonomously. Data uploaded to the space segment during a communications window describes rover and lander operations for an entire day