Fractal geometry of critical Potts clusters

Numerical simulations on the total mass, the numbers of bonds on the hull, external perimeter, singly connected bonds and gates into large fjords of the Fortuin-Kasteleyn clusters for two-dimensional q-state Potts models at criticality are presented. The data are found consistent with the recently derived corrections-to-scaling theory. However, the approach to the asymptotic region is slow, and the present range of the data does not allow a unique identification of the exact correction exponentsComment: 7 pages, 8 figures, Late

”Kansankollektiivin perustaminen on kuin taivaaseen meneminen”:Kiinan sisällissota ja kommunistisen Kiinan alkuvaiheet keskikoulun ja peruskoulun historian oppikirjoissa 1966–1999

Tiivistelmä. Tutkimus tarkastelee vuosina 1966–1999 julkaistujen keskikoulun ja peruskoulun historian oppikirjojen kuvausta Kiinan 1920-luvun lopulla alkaneesta sisällissodasta ja vuonna 1949 perustetun kansantasavallan alkuvaiheista 1960-luvun alkupuolelle saakka. Tutkimuksen keskeisenä tavoitteena on tarkastella, miksi kuvaus oli juuri tietynlainen, ja toisaalta vertailla ja analysoida aineistossa tapahtunutta kuvauksen muutosta. Tutkimuksen menetelminä toimivat sisällönanalyysi ja vertaileva metodi. Tutkimus jakaantuu temaattisesti kolmeen osioon: Kiinan sisällissodan kuvauksen tarkasteluun, kansantasavallan perustamisen ja suurta harppausta edeltäneiden uudistusten kuvauksen tarkasteluun sekä suuren harppauksen kuvauksen tarkasteluun. Aineisto jakaantuu suomettumisen aikaisiin oppikirjoihin ja suomettumisen jälkeisiin oppikirjoihin siten, että ensimmäiseen osaan on sisällytetty keskikoulun oppikirjat ja peruskoulun ensimmäiset oppikirjasarjat, ja toiseen osaan Kekkosen ajan ja vuoden 1985 opetussuunnitelman jälkeiset uudet kirjasarjat. Tutkimuksessa havaittiin, että oppikirjojen kuvaukset olivat voimakkaasti sidoksissa aikansa poliittiseen ympäristöön, poliittiseen korrektiuteen ja kouluhallituksen asettamiin vaatimuksiin. Kommunistista Kiinaa käsiteltiin kirjoissa kaikkein eniten 1970-luvun peruskoulun oppikirjoissa, joissa kommunisteja ja sosialismia myös ylistettiin vuolaimmin. Muutoksen jyrkkyyttä kuvastaa se, että 1960-luvulla julkaistuun keskikoulun oppikirjaan, jossa Kiinan kommunisteja ei kuvattu kovinkaan suopeasti, ilmestyi 1970-luvun alun painokseen voimakkaasti kommunisteja ja sosialismia ylistänyttä tekstiä, samalla kun kriittiseksi tulkittavissa olevat kohdat oli poistettu. Oppikirjat pyrkivät enimmäkseen noudattamaan valtion ulkopoliittista linjaa, mutta enemmän niiden laatimiseen vaikutti sisäpoliittinen paine, kirjatarkastukset ja itsesensuuri. Tätä kuvastaa se, että vaikka 1980-luvulla Suomen ulkopolitiikan viralliset linjaukset säilyivät pitkälti samana, kutistui kirjojen Kiinan sisällissotaa ja kansantasavallan vaiheita käsitellyt sisältö huomattavasti, ja kuvaus muuttui selkeästi neutraalimpaan suuntaan. Tutkittavan ajanjakson lopulla kuvaus keskittyi jo enemmän Kiinan epäkohtiin, eikä sosialismin ylistämistä katsottu enää tarpeelliseksi. Kommunistista Kiinaa voitiin kuitenkin myös kritisoida jopa 1970-luvun kirjoissa. Terävämpään kritiikkiin tukea haettiin Neuvostoliiton linjauksista, eikä kritiikki kohdistunut missään vaiheessa sosialismiin, vain korkeintaan Kiinan tapaan soveltaa sitä. Aineistosta olikin havaittavissa, että ylistävän kuvauksen varsinaisena kohteena oli sosialismi, Kiinan toimiessa vain ylistyksen välineenä. Kirjojen kuvauksissa Kiinan kansatasavallan johto saattoi tehdä huonoja ratkaisuja, mutta loppujen lopuksi sosialismiin siirtyminen oli aina positiivinen asia, kunhan radikaaleimpia linjauksia tarkistettiin parempaan suuntaan

Interface dynamics and kinetic roughening in fractals

We consider the dynamics and kinetic roughening of single-valued interfaces in two-dimensional fractal media. Assuming that the local height difference distribution function of the fronts obeys Levý statistics with a well-defined power-law decay exponent, we derive analytic expressions for the local scaling exponents. We also show that the kinetic roughening of the interfaces displays anomalous scaling and multiscaling in the relevant correlation functions. For invasion percolation models, the exponents can be obtained from the fractal geometry of percolation clusters. Our predictions are in excellent agreement with numerical simulations.Peer reviewe

Specified Species in Gingival Crevicular Fluid Predict Bacterial Diversity

BACKGROUND: Analysis of gingival crevicular fluid (GCF) samples may give information of unattached (planktonic) subgingival bacteria. Our study represents the first one targeting the identity of bacteria in GCF. METHODOLOGY/PRINCIPAL FINDINGS: We determined bacterial species diversity in GCF samples of a group of periodontitis patients and delineated contributing bacterial and host-associated factors. Subgingival paper point (PP) samples from the same sites were taken for comparison. After DNA extraction, 16S rRNA genes were PCR amplified and DNA-DNA hybridization was performed using a microarray for over 300 bacterial species or groups. Altogether 133 species from 41 genera and 8 phyla were detected with 9 to 62 and 18 to 64 species in GCF and PP samples, respectively, per patient. Projection to latent structures by means of partial least squares (PLS) was applied to the multivariate data analysis. PLS regression analysis showed that species of genera including Campylobacter, Selenomonas, Porphyromonas, Catonella, Tannerella, Dialister, Peptostreptococcus, Streptococcus and Eubacterium had significant positive correlations and the number of teeth with low-grade attachment loss a significant negative correlation to species diversity in GCF samples. OPLS/O2PLS discriminant analysis revealed significant positive correlations to GCF sample group membership for species of genera Campylobacter, Leptotrichia, Prevotella, Dialister, Tannerella, Haemophilus, Fusobacterium, Eubacterium, and Actinomyces. CONCLUSIONS/SIGNIFICANCE: Among a variety of detected species those traditionally classified as Gram-negative anaerobes growing in mature subgingival biofilms were the main predictors for species diversity in GCF samples as well as responsible for distinguishing GCF samples from PP samples. GCF bacteria may provide new prospects for studying dynamic properties of subgingival biofilms

Studies Needed to Address Public Health Challenges of the 2009 H1N1 Influenza Pandemic: Insights from Modeling

In light of the 2009 influenza pandemic and potential future pandemics, Maria Van Kerkhove and colleagues anticipate six public health challenges and the data needed to support sound public health decision making.The authors acknowledge support from the Bill & Melinda Gates Foundation (MDVK, CF, NMF); Royal Society (CF); Medical Research Council (MDVK, CF, PJW, NMF); EU FP7 programme (NMF); UK Health Protection Agency (PJW); US National Institutes of Health Models of Infectious Disease Agent Study program through cooperative agreement 1U54GM088588 (ML); NIH Director's Pioneer Award, DP1-OD000490-01 (DS); EU FP7 grant EMPERIE 223498 (DS); the Wellcome Trust (DS); 3R01TW008246-01S1 from Fogerty International Center and RAPIDD program from Fogerty International Center with the Science & Technology Directorate, Department of Homeland Security (SR); and the Institut de Veille Sanitaire Sanitaire funded by the French Ministry of Health (J-CD). The funders played no role in the decision to submit the article or in its preparation

Using mutual information to investigate non-linear correlation between AE index, ULF Pc5 wave activity and electron precipitation

In this study, we use mutual information from information theory to investigate non-linear correlation between geomagnetic activity indicated by auroral electrojet (AE) index with both the global ultra low frequency (ULF) Pc5 wave power and medium energy (>= 30 keV) electron precipitation at the central outer radiation belt. To investigate the energy and magnetic local time (MLT) dependence of the non-linearity, we calculate the mutual information and Pearson correlation coefficient separately for three different energy ranges (30-100 keV, 100-300 keV and >= 300 keV) and four different MLT sectors (0-6, 6-12, 12-18, 18-24). We compare results from 2 years 2004 and 2007 representing geomagnetically more active and less active years, respectively. The correlation analysis between the AE index and electron precipitation shows a clear MLT and energy dependence in both active and quiet conditions. In the two lowest energy ranges of the medium energy electrons (30-100 keV and 100-300 keV) both non-linear correlation and Pearson correlation indicate strong dependence with the AE index in the dawn sector. The linear dependence indicated by the Pearson correlation coefficient decreases from dawn to dusk while the change in the non-linear correlation is smaller indicating an increase in the non-linearity from dawn to dusk. The non-linearity between the AE index and electron precipitation is larger at all MLT sectors except MLTs 6-12 during geomagnetically more active year when larger amount of the activity is driven by interplanetary coronal mass ejections (ICMEs) compared to lower activity year with high speed stream (HSS) and stream interaction region (SIR) driven activity. These results indicate that the processes leading to electron precipitation become more non-linear in the dusk and during geomagnetically more active times when the activity is driven by ICMEs. The non-linearity between the AE index and global ULF Pc5 activity is relatively low and seems not to be affected by the difference in the geomagnetic activity during the 2 years studied.Peer reviewe

Outer Van Allen belt trapped and precipitating electron flux responses to two interplanetary magnetic clouds of opposite polarity

Recently, it has been established that interplanetary coronal mass ejections (ICMEs) can dramatically affect both trapped electron fluxes in the outer radiation belt and precipitating electron fluxes lost from the belt into the atmosphere. Precipitating electron fluxes and energies can vary over a range of timescales during these events. These variations depend on the initial energy and location of the electron population and the ICME characteristics and structures. One important factor controlling electron dynamics is the magnetic field orientation within the ejecta that is an integral part of the ICME. In this study, we examine Van Allen Probes (RBSPs) and Polar Orbiting Environmental Satellites (POESs) data to explore trapped and precipitating electron fluxes during two ICMEs. The ejecta in the selected ICMEs have magnetic cloud characteristics that exhibit the opposite sense of the rotation of the north-south magnetic field component (B-Z). RBSP data are used to study trapped electron fluxes in situ, while POES data are used for electron fluxes precipitating into the upper atmosphere. The trapped and precipitating electron fluxes are qualitatively analysed to understand their variation in relation to each other and to the magnetic cloud rotation during these events. Inner magnetospheric wave activity was also estimated using RBSP and Geostationary Operational Environmental Satellite (GOES) data. In each event, the largest changes in the location and magnitude of both the trapped and precipitating electron fluxes occurred during the southward portion of the magnetic cloud. Significant changes also occurred during the end of the sheath and at the sheath-ejecta boundary for the cloud with south to north magnetic field rotation, while the ICME with north to south rotation had significant changes at the end boundary of the cloud. The sense of rotation of B-Z and its profile also clearly affects the coherence of the trapped and/or precipitating flux changes, timing of variations with respect to the ICME structures, and flux magnitude of different electron populations. The differing electron responses could therefore imply partly different dominant acceleration mechanisms acting on the outer radiation belt electron populations as a result of opposite magnetic cloud rotation.Peer reviewe

CHARACTERISATION AND IN VITRO AND IN VIVO EVALUATION OF SUPERCRITICAL-CO2-FOAMED B-TCP/PLCL COMPOSITES FOR BONE APPLICATIONS

Most synthetic bone grafts are either hard and brittle ceramics or paste-like materials that differ in applicability from the gold standard autologous bone graft, which restricts their widespread use. Therefore, the aim of the study was to develop an elastic, highly porous and biodegradable beta-tricalciumphosphate/poly(L-lactide-co-epsilon-caprolactone) (beta-TCP/PLCL) composite for bone applications using supercritical CO2 foaming. Ability to support osteogenic differentiation was tested in human adipose stem cell (hASC) culture for 21 d. Biocompatibility was evaluated for 24 weeks in a rabbit femur-defect model. Foamed composites had a high ceramic content (50 wt%) and porosity (65-67 %). After 50 % compression, in an aqueous environment at 37 degrees C, tested samples returned to 95 % of their original height. Hydrolytic degradation of beta-TCP/PLCL composite, during the 24-week follow-up, was very similar to that of porous PLCL scaffold both in vitro and in vivo. Osteogenic differentiation of hASCs was demonstrated by alkaline phosphatase activity analysis, alizarin red staining, soluble collagen analysis, immunocytochemical staining and qRT-PCR. In vitro, hASCs formed a pronounced mineralised collagen matrix. A rabbit femur defect model confirmed biocompatibility of the composite. According to histological Masson-Goldner's trichrome staining and micro-computed tomography, beta-TCP/PLCL composite did not elicit infection, formation of fibrous capsule or cysts. Finally, native bone tissue at 4 weeks was already able to grow on and in the beta-TCP/PLCL composite. The elastic and highly porous beta-TCP/PLCL composite is a promising bone substitute because it is osteoconductive and easy-to-use and mould intraoperatively.Peer reviewe