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Size-selective predation on pelagic microorganisms in Arctic freshwaters

Herbivorous zooplankton may have a pronounced influence on pelagic microorganisms in Arctic freshwaters. We quantified experimentally the size-selective feeding of several zooplankton groups on pelagic microorganisms in high Arctic tundra systems. Our experiments and field study focused on dominant herbivores in Arctic freshwaters, including the cladoceran Dophnia, the copepod Diaptomus and the an

Early Permian palynostratigraphy of the northern Heimefrontfjella mountain range, Dronning Maud Land, Antarctica

Permian rocks from five localities in the northern Heimefrontfjella have been investigated palynologically and identifiable palynomorphs are present in samples from three of them, namely A and C in Milorgfjella and Lidkvarvet in Sivorgfjella. Eighty palynomorph taxa are recognized and two new combinations are proposed, Converrucosisporites gradegranulatus (Anderson) Lindstrom, comb, nov, and Canna

Percutaneous transluminal angioplasty of crural arteries: diabetes and other factors influencing outcome

OBJECTIVE: to evaluate the efficacy of percutaneous transluminal angioplasty (PTA) of the crural arteries. PATIENTS AND METHODS: a retrospective review of patients treated with PTA of at least one crural artery during an 8-year period (1990--1997). RESULTS: one hundred and fifty-five legs in 140 consecutive patients (mean age 74 years, range 38--91 years) were treated. In 76% a more proximal lesio

Growth and characterization of GaAs and InAs nano-whiskers and InAs/GaAs heterostructures

Semiconducting InAs and GaAs nano-whiskers have been grown using a chemical beam epitaxy approach in combination with size-selected catalytic Au aerosol particles. The characterization of InAs and GaAs whiskers shows high crystalline quality as seen by transmission electron microscopy. Gate-dependent transport measurements suggests a diffusive electronic transport mechanism. We have also combined

The nitrogen fixation potential of arctic cryptogram species is influenced by enhanced UV-B radiation

Abstract. Effects of enhanced UV-B (representing a 15% ozone depletion) on cyanobacterial nitrogen fixation were measured at a high arctic site (Adventdalen, 79°N, Svalbard) and a subarctic site (Abisko, 68°N, Sweden). Nitrogen fixation potential (acetylene reduction) by cyanobacteria associated with the moss Sanionia uncinata in vegetation exposed to experimentally enhanced levels of UV-B for 3 a

Protein expression analysis: from "tip of the iceberg" to a global method.

In this review I will describe the advances that have recently been made in "traditional" two-dimensional gel based protein expression analysis. A major jump has been made toward the automation of gel image analysis and comparison, one of the major bottlenecks in the analysis chain as well as the automation of spot excision and preparation for mass spectrometric analysis. Currently the gel-based "

Applications of Rice's formula in oceanographic and environmental problems

Popular Abstract in Swedish Den här avhandlingen består av fem papper (A-E) som samtliga är tillämpningar av Rice's formel. Tillämpningsområdena är inom oceanografi och miljö. De tre första papperna behandlar egenskaper hos mötande havsvågor, det vill säga vågor som ett fartyg möter när det seglar på havet. Papper A syftar till att hitta en formel för att räkna ut intensiteten av sådana vågor. SpThis thesis is based on five papers (A-E), all treating various applications of Rice's formula. The areas of application are oceanographic and environmental problems. The first three papers treat properties of encountering waves, that is, waves that a ship encounters while sailing on the ocean. Paper A addresses the problem of computing the intensity of such waves and, in particular, the intensit

Methods for protective clothing evaluation

The international Technical report , ISO/TR 11079, will soon be due for revision. The report suggests that thermal insulation values from a moving thermal manikin can be used to match requirements specified by the IREQ-method. It is known from prior work that insulation values measured with human subjects can be reduced by up to 70 % from the value measured on a standing thermal manikin. This pape

Linkage between nuclear and mitochondrial DNA sequences in avian malaria parasites: Multiple cases of cryptic speciation?

Analyses of mitochondrial cytochrome b diversity among avian blood parasites of the genera Haemoproteus and Plasmodium suggest that there might be as many lineages of parasites as there are species of birds. This is in sharp contrast to the approximately 175 parasite species described by traditional methods based on morphology using light microscopy. Until now it has not been clear to what extent

Induction of CD36 by all-trans retinoic acid: retinoic acid receptor signaling in the pathogenesis of atherosclerosis

Scavenger receptors mediating the uptake of oxidized low-density lipoproteins (oxLDL) by macrophages play a crucial role in foam cell formation during atherosclerosis. One member of this receptor family, the thrombospondin receptor CD36, has recently been shown to mediate a major part of the oxLDL-induced aggravation of atherosclerotic lesions. Here, we show that the expression of CD36 protein and

Late Ordovician-Early Silurian facies development and stratigraphy of Jämtland, central Sweden

Popular Abstract in Swedish Denna doktorsavhandling behandlar de 450-440 miljoner år gamla marina sediment som idag påträffas i form av deformerade och uppveckade sedimentära bergarter vid randen av den svenska fjällkedjan i Jämtland. Målet med studien har varit att kartlägga och tolka hur, och i vilken utsträckning, lokala och globala händelser påverkat de depositionsmiljöer som sedimenten avlagrThis thesis is based on studies of Lower Palaeozoic sedimentary successions within the central Scandinavian Caledonides. These deposits have been transported by considerable nappe displacement (several kilometres), and are today relatively isolated from the nearest coeval outcrops (Dalarna 250 km, Oslo Region 350 km). As a consequence, and due to the previously limited biostratigraphical control t