The influence of tree age and microhabitat quality on the occurrence of crustose lichens associated with old oaks

Questions: How do tree age, microhabitat characteristics and epiphytic competitors affect the occurrence of crustose lichens associated with old oaks? How do microhabitat characteristics and microclimate affect the cover of competitors (bryophytes and macrolichens)? How do microhabitat characteristics cor¬relate with microclimatic variables? Location: Southeast Sweden. Methods: Eight crustose lichen species were surveyed on 165 Quercus robur trees, 17-478 years old, at three study sites. The occurrence patterns of these species were examined at two spatial scales: among trees and within trees. Occurrence patterns within trees were examined in 10 cm × 10 cm plots at all four cardinal aspects at different heights from 0.5 to 4.5 m above the ground. Results: At the tree level, age-related factors were the most important predictors of species occurrence. All species were more frequent on trees > 100 years than on younger trees. At the plot level, the frequency of occurrence increased with increasing bark crevice depth. The frequencies of all study species de¬creased with increasing cover of bryophytes. Bryophytes were in turn more frequent in plots that were exposed to rainwater and showed a low evaporation rate. Patches most exposed to rainwater were directed upwards, and the lowest evaporation rates occurred on the northern side of the trunks. Conclusions: For many crustose lichens the association with old oak trees seems at least partly to depend on their preference for the deep bark crevices that only occur on old trees. Trees represent epiphyte habitat patches that differ in size due to within-tree variability in habitat quality, such as bark crevice depth and microclimate. This study shows that variability at a finer scale, within habitat patches, contribute to explain species occurrence patterns at habitat patch level

Sample Preparation for in vitro Analysis of Iodine in Thyroid Tissue using X-ray Fluorescence

Iodine is enriched and stored in the thyroid gland. Due to several factors, the size of the thyroid iodine pool varies both between individuals and within individuals over time. Excess iodine as well as iodine deficiency may promote thyroid cancer. Therefore, knowledge of iodine content and distribution within thyroid cancer tissue is of interest. X-ray fluorescence analysis (XRF) and secondary ion mass spectrometry (SIMS) are two methods that can be used to assess iodine content in thyroid tissue. With both techniques, choice of sample preparation affects the results. Aldehyde fixatives are required for SIMS analysis while a freezing method might be satisfactory for XRF analysis. The aims of the present study were primarily to evaluate a simple freezing technique for preserving samples for XRF analysis and also to use XRF to evaluate the efficacy of using aldehyde fixatives to prepare samples for SIMS analysis. Ten porcine thyroids were sectioned into four pieces that were either frozen or fixed in formaldehyde, glutaraldehyde, or a modified Karnovsky fixative. The frozen samples were assessed for iodine content with XRF after 1 and 2 months, and the fixed samples were analyzed for iodine content after 1 week. Freezing of untreated tissue yielded no significant iodine loss, whereas fixation with aldehydes yielded an iodine loss of 14–30%, with Karnovsky producing the least loss

Bruk av sosiale medier ved rekruttering.

Den foreliggende studien prøver å forstå hvordan sosiale medier i rekrutteringsprosessen brukes i norsk næringsliv, for så kunne se på fordeler og ulemper ved dette. Ved kvalitativ metode og herunder dybdeintervjuer har studien fanget essensen i informantenes oppfatninger. Studien ser problemstillingen fra både arbeidsgivers og arbeidssøkers ståsted. Som teoretisk fundament ser studien på foreliggende teori hvor sosiale medier og rekruttering blir tatt opp. Dette er teori som danner bakgrunnen for spørsmålene til dybdeintervjuene med informantene. Det viste seg at selv de personene som ikke bruker sosiale medier, bruker dette i liten grad og noen ganger ubevisst. Videre kom studien frem til en felles forståelse for at sosiale medier er tids- og kostnadsbesparende, men også et sted for å aktivt finne nye ansatte. Både arbeidsgivere og arbeidssøkere har forståelse for at sosiale medier blir brukt for informasjon om hverandre. Felles for begge er at de ser det som rettferdig at det brukes. De er begge av oppfatningen at det en selv legger ut, er en selv ansvarlig for. Studien prøver også å belyse noen etiske aspekter ved denne bruken

Development of an in situ assay for simultaneous detection of the genomic and replicative form of PCV2 using padlock probes and rolling circle amplification

<p>Abstract</p> <p>Background</p> <p>In this study we utilized padlock probes and rolling circle amplification as a mean to detect and study the replication of porcine circovirus type 2 (PCV2) in cultured cells and in infected tissue. Porcine circovirus type 2 is a single-stranded circular DNA virus associated with several severe diseases, porcine circovirus diseases (PCVD) in pigs, such as postweaning multisystemic wasting syndrome. The exact reason and mechanisms behind the trigger of PCV2 replication that is associated with these diseases is not well-known. The virus replicates with rolling circle replication and thus also exists as a double-stranded replicative form.</p> <p>Results</p> <p>By applying padlock probes and rolling circle amplification we could not only visualise the viral genome but also discriminate between the genomic and the replicative strand in situ. The genomic strand existed in higher numbers than the replicative strand. The virus accumulated in certain nuclei but also spread into the cytoplasm of cells in the surrounding tissue. In cultured cells the average number of signals increased with time after infection.</p> <p>Conclusions</p> <p>We have developed a method for detection of both strands of PCV2 in situ that can be useful for studies of replication and in situ detection of PCV2 as well as of DNA viruses in general.</p

Metabolism of a subtidal rocky mussel reef in a high-temperate setting: pathways of organic C flow

Peer reviewe

Dwell time symmetry in random walks and molecular motors

The statistics of steps and dwell times in reversible molecular motors differ from those of cycle completion in enzyme kinetics. The reason is that a step is only one of several transitions in the mechanochemical cycle. As a result, theoretical results for cycle completion in enzyme kinetics do not apply to stepping data. To allow correct parameter estimation, and to guide data analysis and experiment design, a theoretical treatment is needed that takes this observation into account. In this paper, we model the distribution of dwell times and number of forward and backward steps using first passage processes, based on the assumption that forward and backward steps correspond to different directions of the same transition. We extend recent results for systems with a single cycle and consider the full dwell time distributions as well as models with multiple pathways, detectable substeps, and detachments. Our main results are a symmetry relation for the dwell time distributions in reversible motors, and a relation between certain relative step frequencies and the free energy per cycle. We demonstrate our results by analyzing recent stepping data for a bacterial flagellar motor, and discuss the implications for the efficiency and reversibility of the force-generating subunits. Key words: motor proteins; single molecule kinetics; enzyme kinetics; flagellar motor; Markov process; non-equilibrium fluctuations.Comment: revtex, 15 pages, 8 figures, 2 tables. v2: Minor revision, corrected typos, added references, and moved mathematical parts to new appendice

Rennestein: film noir i moderne tid

Skriftlig del av bacheloroppgave i DIGME, 2013Vi har laget vår egenproduserte film noir til den praktiske delen av Bacheloroppgaven. Denne filmen vil bli dratt inn som eksempel i løpet av oppgaven. Mesteparten av denne skriftlige oppgaven handler om film noir, og hvordan den har forandret seg frem til moderne tid. Vi vil se på disse tendensene ved å gå gjennom dens historie, og også trekke paralleller til vår egenproduserte film. I denne oppgaven vil det bli gått igjennom begreper som sjanger, stil, film noir, neo noir, og film noirens mise-en-scène. Det vil også bli forklart hvilken metode vi har tatt i bruk for å komme frem til våres konklusjon. Til slutt i oppgaven vil vi drøfte om vår egenproduserte film kan karakteriseres som en moderne film noir, og om den inneholder alle de kriteriene denne stilarten krever

Assessing Innovations in High-Speed Rail Infrastructure

With a focus on infrastructure-related innovations for HSR, this paper aims at assessing their impacts in relation to the targets of punctuality, capacity, and life cycle costs. The paper presents a hybrid assessment methodology combing different approaches to assess effects on the named KPI. This contributes to reducing the existing gap that is found in the research literature

The first Swedish H1N2 swine influenza virus isolate represents an uncommon reassortant

The European swine influenza viruses (SIVs) show considerable diversity comprising different types of H1N1, H3N2, and H1N2 strains. The intensifying full genome sequencing efforts reveal further reassortants within these subtypes. Here we report the identification of an uncommon reassortant variant of H1N2 subtype influenza virus isolated from a pig in a multisite herd where H1N2 swine influenza was diagnosed for the first time in Sweden during the winter of 2008-2009. The majority of the European H1N2 swine influenza viruses described so far possess haemagglutinin (HA) of the human-like H1N2 SIV viruses and the neuraminidase (NA) of either the European H1N2 or H3N2 SIV-like viruses. The Swedish isolate has an avian-like SIV HA and a H3N2 SIV-like NA, which is phylogenetically more closely related to H3N2 SIV NAs from isolates collected in the early '80s than to the NA of H3N2 origin of the H1N2 viruses isolated during the last decade, as depicted by some German strains, indicative of independent acquisition of the NA genes for these two types of reassortants. The internal genes proved to be entirely of avian-like SIV H1N1 origin. The prevalence of this SIV variant in pig populations needs to be determined, as well as the suitability of the routinely used laboratory reagents to analyze this strain