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

Effects of intensified silviculture on timber production and its economic profitability in boreal Norway spruce and Scots pine stands under changing climatic conditions

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Influence of Small Control Levers of Grapple Loader on Muscle Strain, Productivity and Control Errors

Small-sized mini-levers were compared to conventional levers in forwarder grapple loading of timber using a forest machine simulator in clear-cutting and thinning conditions. No effect on time consumption per burden was observed, but muscle constriction in the trapezius muscle measured using EMG was lower when the mini-lever option was used. Control errors were measured by counting the contacts between the remaining trees and the machine elements. These were interpreted to result in damage to the trees. The frequency of this kind of damages was significantly smaller when using the mini-lever option

Comminution of Logging Residues with Evolution 910R chipper, MOHA chipper truck, and Morbark 1200 tub grinder

This study is part of the ongoing national Bioenergy Research Programme in Finland. The study looked into the quality of chips made of logging residues composed predominantly of spruce wood. In addition, the productivity of the Evolution 910R chipper, the MOHA chipper truck, and the Morbark 1200 tub grinder was studied. The three machines studied were capable of producing acceptable chips for heat generation plants. The particle-size distribution was good in all cases and the proportion of large particles and the fine fraction was small. The ash content of the chips was low due to carefulness in the handling of logging residues. The moisture content was typical for logging residues stored at the logging site for some months. The machine productivity values obtained were as follows: Evolution = 65 m3 loose/E15-h, MOHA = 23 m3 loose/E15-h, and Morbark = 5060 m3 loose/E15-h. These results are preliminary; a follow-up study is needed for more reliable results to be obtained concerning the productivities

Motion of flux transfer events: a test of the Cooling model

The simple model of reconnected field line motion developed by Cooling et al. (2001) has been used in several recent case studies to explain the motion of flux transfer events across the magnetopause. We examine 213 FTEs observed by all four Cluster spacecraft under a variety of IMF conditions between November 2002 and June 2003, when the spacecraft tetrahedron separation was ~5000 km. Observed velocities were calculated from multi-spacecraft timing analysis, and compared with the velocities predicted by the Cooling model in order to check the validity of the model. After excluding three categories of FTEs (events with poorly defined velocities, a significant velocity component out of the magnetopause surface, or a scale size of less than 5000 km), we were left with a sample of 118 events. 78% of these events were consistent in both direction of motion and speed with one of the two model de Hoffmann-Teller (dHT) velocities calculated from the Cooling model (to within 30° and a factor of two in the speed). We also examined the plasma signatures of several magnetosheath FTEs; the electron signatures confirm the hemisphere of connection indicated by the model in most cases. This indicates that although the model is a simple one, it is a useful tool for identifying the source regions of FTEs

Imbibition in Disordered Media

The physics of liquids in porous media gives rise to many interesting phenomena, including imbibition where a viscous fluid displaces a less viscous one. Here we discuss the theoretical and experimental progress made in recent years in this field. The emphasis is on an interfacial description, akin to the focus of a statistical physics approach. Coarse-grained equations of motion have been recently presented in the literature. These contain terms that take into account the pertinent features of imbibition: non-locality and the quenched noise that arises from the random environment, fluctuations of the fluid flow and capillary forces. The theoretical progress has highlighted the presence of intrinsic length-scales that invalidate scale invariance often assumed to be present in kinetic roughening processes such as that of a two-phase boundary in liquid penetration. Another important fact is that the macroscopic fluid flow, the kinetic roughening properties, and the effective noise in the problem are all coupled. Many possible deviations from simple scaling behaviour exist, and we outline the experimental evidence. Finally, prospects for further work, both theoretical and experimental, are discussed.Comment: Review article, to appear in Advances in Physics, 53 pages LaTe

Public health impacts of city policies to reduce climate change:Findings from the URGENCHE EU-China project

Background: Climate change is a global threat to health and wellbeing. Here we provide findings of an international research project investigating the health and wellbeing impacts of policies to reduce greenhouse gas emissions in urban environments.Methods: Five European and two Chinese city authorities and partner academic organisations formed the project consortium. The methodology involved modelling the impact of adopted urban climate-change mitigation transport, buildings and energy policy scenarios, usually for the year 2020 and comparing them with business as usual (BAU) scenarios (where policies had not been adopted). Carbon dioxide emissions, health impacting exposures (air pollution, noise and physical activity), health (cardiovascular, respiratory, cancer and leukaemia) and wellbeing (including noise related wellbeing, overall wellbeing, economic wellbeing and inequalities) were modelled. The scenarios were developed from corresponding known levels in 2010 and pre-existing exposure response functions. Additionally there were literature reviews, three longitudinal observational studies and two cross sectional surveys.Results: There are four key findings. Firstly introduction of electric cars may confer some small health benefits but it would be unwise for a city to invest in electric vehicles unless their power generation fuel mix generates fewer emissions than petrol and diesel. Second, adopting policies to reduce private car use may have benefits for carbon dioxide reduction and positive health impacts through reduced noise and increased physical activity. Third, the benefits of carbon dioxide reduction from increasing housing efficiency are likely to be minor and co-benefits for health and wellbeing are dependent on good air exchange. Fourthly, although heating dwellings by in-home biomass burning may reduce carbon dioxide emissions, consequences for health and wellbeing were negative with the technology in use in the cities studied.Conclusions: The climate-change reduction policies reduced CO2 emissions (the most common greenhouse gas) from cities but impact on global emissions of CO2 would be more limited due to some displacement of emissions. The health and wellbeing impacts varied and were often limited reflecting existing relatively high quality of life and environmental standards in most of the participating cities; the greatest potential for future health benefit occurs in less developed or developing countries.</p

ARGUMENTOINTIA PAINOTTAVA LUONNONTIETEEN KOULUOPETUS – KATSAUS TAVOITTEISIIN

Tässä artikkelissa tarkastellaan argumentointia painottavan luonnontieteen kouluopetuksen tavoitteita kansainvälisen tutkimuskirjallisuuden pohjalta. Tarkasteluun valittiin 14 luonnontieteen kouluopetuksen kansainvälistä tutkimusartikkelia, joissa esiintyvät kuvaukset argumentoinnin tavoitteista luokiteltiin niissä esiintyvien teemojen perusteella. Tavoitekuvauksista erottui kolme pääteemaa: koulussa opetettavien luonnontieteiden autenttisuuden lisääminen, oppilaiden ajattelu- ja vuorovaikutustaitojen kehittymisen tukeminen sekä sisältötiedon osaamisen ja luonnontieteellisen sivistyksen syventäminen. Autenttisen kuvan välittäminen luonnontieteistä oppilaille näyttäytyi edellytyksenä muiden oppimistavoitteiden saavuttamiselle. Tavoitteiden tunnistaminen edesauttaa argumentoinnin painottamista suomalaisessa luonnontieteen opetuksessa.Tässä artikkelissa tarkastellaan argumentointia painottavan luonnontieteen kouluopetuksen tavoitteita kansainvälisen tutkimuskirjallisuuden pohjalta. Tarkasteluun valittiin 14 luonnontieteen kouluopetuksen kansainvälistä tutkimusartikkelia, joissa esiintyvät kuvaukset argumentoinnin tavoitteista luokiteltiin niissä esiintyvien teemojen perusteella. Tavoitekuvauksista erottui kolme pääteemaa: koulussa opetettavien luonnontieteiden autenttisuuden lisääminen, oppilaiden ajattelu- ja vuorovaikutustaitojen kehittymisen tukeminen sekä sisältötiedon osaamisen ja luonnontieteellisen sivistyksen syventäminen. Autenttisen kuvan välittäminen luonnontieteistä oppilaille näyttäytyi edellytyksenä muiden oppimistavoitteiden saavuttamiselle. Tavoitteiden tunnistaminen edesauttaa argumentoinnin painottamista suomalaisessa luonnontieteen opetuksessa