The liquid krypton calorimeter cryogenics for the NA48 experiment

The NA48 cryogenic system has to provide stable thermal conditions (120 K) in a 9000 liter liquid krypton calorimeter, and has to ensure safe and loss free storage of the liquid during idle periods. Direct cooling of the krypton by nitrogen is used in emergency cases, while an intermediate cooler, containing saturated liquid argon at around 10 bar (117 K) is used under normal operation conditions when high thermal stability is needed. The krypton pressure is, during data taking, regulated to a value of (1.05 $\pm$ 0.01) bar for a period of about 8 months of continuous operation of the calorimeter

Displaced midshaft fractures of the clavicle: non-operative treatment versus plate fixation (Sleutel-TRIAL). A multicentre randomised controlled trial

Contains fulltext : 96826.pdf (publisher's version ) (Open Access)BACKGROUND: The traditional view that the vast majority of midshaft clavicular fractures heal with good functional outcomes following non-operative treatment may be no longer valid for all midshaft clavicular fractures. Recent studies have presented a relatively high incidence of non-union and identified speciic limitations of the shoulder function in subgroups of patients with these injuries. AIM: A prospective, multicentre randomised controlled trial (RCT) will be conducted in 21 hospitals in the Netherlands, comparing fracture consolidation and shoulder function after either non-operative treatment with a sling or a plate fixation. METHODS/DESIGN: A total of 350 patients will be included, between 18 and 60 years of age, with a dislocated midshaft clavicular fracture. The primary outcome is the incidence of non-union, which will be determined with standardised X-rays (Antero-Posterior and 30 degrees caudocephalad view). Secondary outcome will be the functional outcome, measured using the Constant Score. Strength of the shoulder muscles will be measured with a handheld dynamometer (MicroFET2). Furthermore, the health-related Quality of Life score (ShortForm-36) and the Disabilities of Arm, Shoulder and Hand (DASH) Outcome Measure will be monitored as subjective parameters. Data on complications, bone union, cosmetic aspects and use of painkillers will be collected with follow-up questionnaires. The follow-up time will be two years. All patients will be monitored at regular intervals over the subsequent twelve months (two and six weeks, three months and one year). After two years an interview by telephone and a written survey will be performed to evaluate the two-year functional and mechanical outcomes. All data will be analysed on an intention-to-treat basis, using univariate and multivariate analyses. DISCUSSION: This trial will provide level-1 evidence for the comparison of consolidation and functional outcome between two standardised treatment options for dislocated midshaft clavicular fractures. The gathered data may support the development of a clinical guideline for treatment of clavicular fractures. TRIAL REGISTRATION: Netherlands National Trial Register NTR2399

De verspreiding en oecologie van Gymnocarpium dryopteris L. (Gebogen driehoeksvaren) in Nederland

Gymnocarpium dryopteris is rather rare in the Netherlands. Distribution and ecology have been surveyed, especially for the period 1979-1991. In this period the species was detected with more than 670 individual stands, 90% at the Kuinderbos. In this article the Kuinderbos population is compared with other Dutch populations. Gymnocarpium dryopteris prefers shadowy ditches, but may grow in various other habitats as well. Especially in the western and southern part of the Netherlands it is growing on walls. The vegetation on the sites belongs to different syntaxa, with a preference for the Quercion (Fago-Quercetum) or plantations (Pseudotsuga) and in the Kuinderbos especially plantations of Picea sitchensis. Gymnocarpium dryopteris is often accompanied by Athyrium filixfemina. Its rhizomes are creeping at 0.5-8 cm below surface, mostly in the ecto-organic layer, but along ditches also in the mineral layer. Most stands are within the influence of ground water. Usually individual stands are small, those with more than 1000 leaves are rare. Individual stands with more than 100 leaves are mostly fertile, with mostly less than 20% of the leaves bearing sori. On walls, small-sized individuals can be fertile as well

Inula conyza DC. bij Urk

Inula conyza DC. is still growing near the former island of Urk, where it was found for the first time in 1957. It grows mostly in a Prunus spinosa vegetation. The accompanying species differ from those of other populations in the Netherlands. Probably /. conyza reached this locality with saplings for the Urkerbos, a wood planted in 1954 – 1959

Inula conyza DC. bij Urk

Inula conyza DC. is still growing near the former island of Urk, where it was found for the first time in 1957. It grows mostly in a Prunus spinosa vegetation. The accompanying species differ from those of other populations in the Netherlands. Probably /. conyza reached this locality with saplings for the Urkerbos, a wood planted in 1954 – 1959

Het Weidehavikskruid (Hieracium caespitosum Dumortier) in de IJsselmeerpolders en aangrenzende gebieden

Hieracium caespitosum appeared very soon (1948) after the reclamation (1942) of the IJsselmeerpolders. The species mainly flowers in June and it takes approximately thirteen days between fertilization and riping of the achenes; therefore, to enable proper dispersal, mowing of the populations should take place in the second half of June. The species is facultative apogamous and is frequently visited by insects, mainly Muscidae en Syrphidae. From the ecological point of view Hieracium caespitosum has been regarded to be a characteristic for Molinion-vegetations. However, on soils which are humous and lutum-rich, the species shows a preference for Arrhenatherion-vegetations; on poor soils it is part of vegetations that are related to the Thero-Airion. In fact only two locations should be looked upon as Molion-vegetations. The increase of 57 hour-squares since 1980 is, at least partly, due to new inventories

Het ‘fluviatiel’ karakter van het dal van de Overijsselse Vecht

The major part of the valley of the river Overijsselse Vecht has been assigned to the Fluviatile District. Of the various species which are regarded as characteristic for this valley, many have suffered a decline since 1976. Their present distribution supports the upstream delimitation of this part of the Fluviatile District, between the villages Ommen and Hardenberg

Ophioglossum vulgatum L. in de bossen van de IJsselmeerpolders

In the Netherlands Ophioglossum vulgatum occurs in a wide variety of habitats, like dune slacks, wetlands, unfertilized grassy pastures and pits. Records from woodlands were scarce. After the reclamation of the IJsselmeer polders thousands of acres have been planted with trees; in these woodlands Ophioglossum has been recorded at 11 localities, mostly growing under a canopy of Ash, on calcareous soils consisting of fine sand, boulder clay or clay

De Noordoostpolder floristisch en plantengeografisch bezien

The Noordoostpolder is one of the polders in the former Zuiderzee, reclaimed in 1941 and 1942. A natural vegetation developed but was destroyed when the land was cultivated. Many adventitious species came into the area together with road construction materials and crop seeds. Nowadays these species have mostly disappeared, only a small number are still present. The polder consists of an area with sandy clay, bordered by an area with loam, sand and peat Calcareous sands are predominant here. It is shown that floristically this border area is quite different from the area with sandy clay, but also from the bordering part of the ‘old land’. 133 species characterize this border area. Many of these species show links with a number of different plant geographical districts. It is concluded that the border area deserves a plant geographical status of its own. In addition it is shown that in the former Zuiderzee-island Schokland the number of species has much decreased. In Urk the number of species increased slightly, but a number of species disappeared and others moved in