Rescaling Relations between Two- and Three-dimensional Local Porosity Distributions for Natural and Artificial Porous Media

Local porosity distributions for a three-dimensional porous medium and local porosity distributions for a two-dimensional plane-section through the medium are generally different. However, for homogeneous and isotropic media having finite correlation-lengths, a good degree of correspondence between the two sets of local porosity distributions can be obtained by rescaling lengths, and the mapping associating corresponding distributions can be found from two-dimensional observations alone. The agreement between associated distributions is good as long as the linear extent of the measurement cells involved is somewhat larger than the correlation length, and it improves as the linear extent increases. A simple application of the central limit theorem shows that there must be a correspondence in the limit of very large measurement cells, because the distributions from both sets approach normal distributions. A normal distribution has two independent parameters: the mean and the variance. If the sample is large enough, LPDs from both sets will have the same mean. Therefore corresponding distributions are found by matching variances of two- and three-dimensional local porosity distributions. The variance can be independently determined from correlation functions. Equating variances leads to a scaling relation for lengths in this limit. Three particular systems are examined in order to show that this scaling behavior persists at smaller length-scales.Comment: 15 PostScript figures, LaTeX, To be published in Physica

Local Entropy Characterization of Correlated Random Microstructures

A rigorous connection is established between the local porosity entropy introduced by Boger et al. (Physica A 187, 55 (1992)) and the configurational entropy of Andraud et al. (Physica A 207, 208 (1994)). These entropies were introduced as morphological descriptors derived from local volume fluctuations in arbitrary correlated microstructures occuring in porous media, composites or other heterogeneous systems. It is found that the entropy lengths at which the entropies assume an extremum become identical for high enough resolution of the underlying configurations. Several examples of porous and heterogeneous media are given which demonstrate the usefulness and importance of this morphological local entropy concept.Comment: 15 pages. please contact [email protected] and have a look at http://www.ica1.uni-stuttgart.de/ . To appear in Physica

Local Percolation Probabilities for a Natural Sandstone

Local percolation probabilities are used to characterize the connectivity in porous and heterogeneous media. Together with local porosity distributions they allow to predict transport properties \cite{hil91d}. While local porosity distributions are readily obtained, measurements of the local percolation probabilities are more difficult and have not been attempted previously. First measurements of three dimensional local porosity distributions and percolation probabilities from a pore space reconstruction for a natural sandstone show that theoretical expectations and experimental results are consistent.Comment: 9 pages, see also http://www.ica1.uni-stuttgart.de , Physica

Garvicin KS and Other Novel Multipeptide Bacteriocins: A Study of Biosynthesis and Mechanism of Action

Garvicin KS (GarKS) is a known member of the relatively novel multi-peptide bacteriocin subgroup from the producer L. garvieae KS1546. Given the urgency and continued development with antimicrobial resistance, there is a great interest in utilizing bacteriocins as alternatives. Characterization is crucial to better understand the mechanisms behind the antimicrobial effect and is important to know before any potential application. Genome analysis of the KS1546 strain revealed a 50 kb plasmid containing the GarKS cluster has a copy number of 1. It was found that GakI, the immunity protein confers immunity, both in L. lactis and S. aureus in a cross-immunity assay. GakR, the biosynthetic regulator was discovered to have a putative activator role for the upregulation of the GarKS cluster 6-fold. GarKS tolerant mutant isolation strategies yielded clues of unreported loci for a tolerant phenotype, namely ycbB and pstA, as well as further corroborating the association of ythA to tolerance. Using fluorescence methods, FITC-GarKS showed unspecific binding to the cell envelope with microscopy and propidium iodide to determine pore formation, indicating a pore forming mechanism. Mining of public databases for GarKS homology was conducted to discover novel and uncharacterized members. Potent and broad inhibition spectrum JenS from Lactobacillus johnsonii and the less efficacious narrower inhibition spectrum HomE from Staphylococcus hominis. Synergy testing for CerL, SubM, JenS, and HomE was done to test varying peptide combinations in relation to efficacy. The methods in this work gave insightful knowledge to fill certain gaps in the knowledge of GarKS and other novel multipeptide bacteriocins in terms of structure, biosynthesis and bioactivity. This sets an important precedent to branching out to use these as alternatives, in cases of potential therapeutics in the age of antimicrobial resistance and for safer food preservation

Porous structure of thick fiber webs

The bulk properties and stochastic pore geometry of finite-thickness fiber webs are studied using a realistic model for the sedimentation of flexible fibers [K. J. Niskanen and M. J. Alava, Phys. Rev. Lett. 73, 3475 (1994)]. The resulting web structure is controlled by a dimensionless number F=Tfwf/tf, where Tf is fiber flexibility, wf fiber width, and tf fiber thickness. The fiber length (≫wf,tf) is irrelevant. With increasing coverage c̄, a crossover occurs at c̄=c0≈1+2F from a vacancy-controlled two-dimensional (2D) structure to a pore-controlled 3D structure. The 3D structures are isomorphic in that the pore dimensions are exponentially distributed, with the decay rate dependent only on F.Peer reviewe

Indications for Systemic Fluoroquinolone Therapy in Europe and Prevalence of Primary-Care Prescribing in France, Germany and the UK:Descriptive Population-Based Study

BACKGROUND AND OBJECTIVES: In the USA the benefit-risk profile of fluoroquinolones for treating patients with acute bacterial sinusitis, acute bacterial exacerbation of chronic bronchitis, and uncomplicated urinary tract infections (uUTIs) is considered unfavorable. However, the number of fluoroquinolone products in the EU indicated and prescribed for these infections is uncertain. The objective of this study was to provide data on indications for fluoroquinolones in Europe and examine the prevalence of prescribing in France, Germany and the UK.METHODS: Descriptive analysis of indications for systemic fluoroquinolone antibiotics across the European Economic Area (EEA) and descriptive analysis of systemic fluoroquinolone antibiotic prescribing in France, Germany and UK electronic health records (2000-2015).RESULTS: All EEA countries had fluoroquinolone products indicated for acute sinusitis, acute bronchitis, or uUTIs, with differences in the number of products between countries for: acute sinusitis (19.5-51.9%), acute bronchitis (22.2-73.4%), and uUTIs (52.0-89.1%). The prevalence of fluoroquinolone prescribing for the treatment of respiratory tract infections (RTIs) appeared to fall with time in all countries and for UTI in France and UK only. Changes were greatest in the UK. In France, Germany, and the UK, respectively: acute sinusitis accounted for 29.5, 20.6, and 40.7% of all oral fluoroquinolone prescriptions for upper RTIs; acute bronchitis accounted for 63.0, 83.0, and 89.9% of all fluoroquinolone prescriptions for lower RTIs; uUTIs accounted for 83.3, 89.9, and 32.2% of all fluoroquinolone prescriptions for UTIs.CONCLUSION: Large numbers of fluoroquinolone products in Europe are listed for the treatment of milder infections such as acute bronchitis, acute sinusitis and uUTIs. Among the countries assessed, fluoroquinolones were commonly prescribed for these conditions and potentially should lead to a review of therapeutic guidelines.</p

Hvem er medfølgende partnere og hvordan sosialiserer de seg? : en kvalitativ studie av medfølgende partnere ved utstasjonering til Singapore

Masteroppgave i psykisk helsearbeid ME-504 2011 – Universitetet i Agder, GrimstadBakgrunnen for prosjektet er at stadig flere nordmenn arbeider utenfor Norges grenser. Mange av disse har med seg sin partner som ikke selv reiser dit for jobben sin skyld. Jeg ønsket en større innsikt i, og en bedre forståelse av hvordan mennesker sosialiserer seg, og hvordan de opplever å være partner i en fremmed kultur. Hensikt og problemstilling: Hensikten med studiet er økt kunnskap om hvem partnere er, hva det vil si for dem å flytte til en annen kultur, og hvordan de sosialiserer seg i en annerledes hverdag. Mer innsikt i tematikken vil være av vesentlig betydning både for de menneskene som selv vil komme i en tilsvarende situasjon, men også for de organisasjoner som arbeider på denne måten. Kunnskapen jeg søkte kan slik sett være til hjelp for enkeltpersoner og hvordan ulike organisasjoner kan tilrettelegge for partnere som flytter i denne forbindelse. Metode: For å få den dybde jeg trengte for å få svar på problemstillingen, valgte jeg to tilnærmingsmetoder. Disse er et kvalitativt forskningsintervju med fire deltakere, og deltakende observasjon i feltet. Resultater: Studien viser at det i hovedsak er kvinner med høyere utdannelse og barn, som er partnere i Singapore. De kommer til Singapore med forventninger om å oppnå personlig utvikling, og de har et ønske om å gi barna erfaringer relatert til språk og en fremmed kultur. Kvinnene ønsker også at oppholdet skal resultere i et bedre familieliv. Flyttingen til en ny kultur innebærer både tap av tidligere identitet og fremveksten av ny identitet. For noen innebærer dette skifte en stor grad av nedstemthet. Partnerne sosialiserer seg ved å skape sosiale nettverk i Norske miljøer i Singapore, og de holder kontakten med venner gjennom sosiale medier. Konklusjon: Studien setter søkelyset på familiepolitikk fra de utstasjonerte sitt ståsted. Ofte er medfølgende partnere høyt utdannede mennesker som selv ikke får tilegnet seg arbeidserfaring og pensjonspoeng. Studien beskriver hvordan de selv mestrer den nye hverdagen og etterfølges av tips til arbeidsgivere og organisasjoner som ønsker å tilrettelegge en familievennlig politikk med tanke på mestring og trivsel. I tillegg vil studien gi rom for refleksjon for de som er eller har vært utstasjonert