This study aims to assess the normal inflow of extraterrestrial chromite to Earth. The results from the investigationare compared to earlier studies of middle Ordovician Orthoceratite Limestone in which 1 - 3 extraterrestrial chromitegrains ( >63 ?Êm ) per kilogram limestone were found. These values have been interpreted as evidence of a twoorders of magnitude increase in the flux of extraterrestrial matter to Earth during a part of middle Ordovician.From an early Paleocene marine sedimentary sequence with known sedimentation rate in Zumaia, northernSpain, 90,5 kilogram of condensed limestone, dated to about 63 Ma, was sampled. The limestone was dissolved inhydrochloric- and hydrofluoric acid and the residue was sieved and searched for opaque minerals under the binocularmicroscope.

Open pit mining creates huge amounts of tailings and waste rock deposits. Due to it's content of sulphide minerals, predominantly pyrite (FeS2), there is a risk of oxidation and formation of acid water containing heavy metals, known as Acid Rock Drainage (ARD). To prevent the process of oxidation, the tailings and waste rock have to be reclaimed. The most commonly used methods of reclamation are a coverage of water or soil. Mining also results in a large-scale interference in the landscape that will make an eternal change of its appearance.

In Automatic Milking Systems (AMS), cows are kept in a free stall barn equipped with one or several milking units (MU). The cows? activities in the system are called cow traffic. There are three types of cow traffic systems: guided, partly-guided and free. Free systems have no gates, allowing the cows access to the feeding and resting areas at any time.

Syftet med detta examensarbete var att undersöka några lärare, lärarstudenter och elevers erfarenheter av samt attityder till faktionstexternas roll i skolan. Detta undersöktes genom halvstrukturerade intervjuer med fyra verksamma grundskolelärare, två lärarstudenter, som har läst svenska minst två år, och genom en gruppintervju med fem gymnasieelever. En enkät användes i urvalssyfte samt som grund för den följande diskussionen. En inventering av skolbiblioteket samt svenskämnesinstitutionen på den skola där de medverkande lärarna arbetar har även genomförts. Resultatet visar att lärarna och lärarstudenterna anser att faktionstexter är intressanta både innehålls- och formmässigt, men att de används alltför sällan i klassrummet.

A new Swedish political approach to forestry was initiated 1993, that put goals of production and environmental issues into equal importance to Swedish Forestry Law. Earlier nature conservation very often declaimed preservation the best way to conserve nature, but recently it is clear that many highly biological values are due to former land use or disturbance. Many old pastures or cultivations dominated by deciduous trees are today characterized by a dense overgrowth of Norway spruce. By actively paying attention to nature in forestry (nature restoration), it is possible to partly reconstruct habitats or disturbances that are necessary to favour the biological values. The aim with this master thesis is to study the nature restoration, (NS, Swedish abbreviation), performed in 11 forest sites in the middle of Sweden 8-14 years ago. Since NS recently have become applied, it has never yet been evaluated.

At seed-growing the aim is to produce a commodity with high germination capacity, good soundness and purity, and also slight admixture of seeds from other species. The capacity of germination and the vigour of the seeds may become impaired in consequence of mechanical damage, infection of diseases, growth of mould, attacks of vermin, high drying temperature, secret germination, sprouting in the ears etc. The germ belongs to the outer and most unprotected parts of the seed, and consequently this is much exposed. Even quite sound seeds can instantaneously have low capability of germination. It can be due to the fact that the seeds are in rest of germination, i.e.

1. Reaction on burial depth and nitrogen availability and placement in competition with a crop In this trial it was investigated how couch grass (Elymus repens) changes its ability to compete in stands of wheat and barley with different burial depth and different amounts and placement of nitrogen. More knowledge in this area can be valuable in the attempt to decrease the use of herbicides and still keep the weeds under control. The trial was carried out in the summer of 2004 as an outdoor pot experiment. The pots contained 15 litres of soil with a surface of 0,06 m2.