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

Vented gas explosions

Explosion venting technology is widely accepted as the effective constructional protection measures against gas and dust explosions.The key problem in venting is the appropriate design of the vent area necessary for an effective release of the material i.e. the pressure developed during explosion did not cause any damage to the plant protected.Current gas explosion vent design standards in the USA (NFPA68, 2002) and European (2007) rely on the vent correlation first published by Bartknecht in 1993 (Siwek, 1996).N FPA 68 also recommends the correlation of Swift (Swift,1983)at low overpressures. For a vent to give no increase in overpressure other than that due to the pressure difference created by the mass flow of unburnt gases through the vent, the vent mass flow rate is assumed to be equal to the maximum mass burning rate of the flame and this consideration should be used as the design mass flow through the vent. Two different methods ( Method I and Method 2) have been proposed based on the Sμ and Sμ (E-1) to describe the maximum mass burning rate given as, mb = ASμpμ=CdeA(2pPμred)o.5 mb =ASgPm =AgSμ(E-I)P μ=Cde4,(2pu Pred)0,5 (2) The equation given in (2) is slightly different from (1) as is about 6.5 times the mass flow of the first method as it takes the effect of (E-1) where E is the expansion ratio. A critical review were carried out for the applicability, validity and limitation on the venting correlations adopted in NFPA 68 and European Standard with 470 literature experimental data, covering a wide range of values for vessel volume and geometries, bursting vent pressure, Pv L/D ratio, maximum reduced pressure, Pred and ignition location. The fuels involved are methane, propane, hydrogen, town gas, ethylene, acetone/air mixtures with the most hazardous near-stoichiornetric fuel-air concentration. Besides, Molkov's equation (Molkov, 2001) which is regarded as alternative venting design offered in NFPA 68 and Bradley and Mitcheson's equation for safe venting design were also analysed on the experimental data for their validity and limitation as well as the proposed methods. From the results, it is clear that Bartknecht's equation gave a satisfactory result with experimental data for K <-5 and Swift's equation (Swift, 1983) can be extended to wider range for Pred> 200 mbar, providing the parameter PV is added into the equation. Method 2 gave a good agreement to most of the experimental data as it followed assumptions applied for correlations given by Bradley and Mitcheson for safe venting design (Bradley and Mitcheson, 1978a,B radley and Mitcheson, 1978b). It is also proven that the vent coefficient, K is confident to be used in quantifying the vessel's geometry for cubic vessel and the use of As/Av term is more favourable for non-cubic vessels. To justify the validity and applicability of the proposed methods, series of simply vented experiments were carried out, involving two different cylindrical volumes i.e. 0.2 and 0.0065 M3. It is found that self acceleration plays important role in bigger vessel in determining the final Pmax inside the vessel. Method 2 gave closer prediction on Pmax in respect with other studied correlations. The investigation of vented gas explosion is explored further with the relief pipe been connected to the vessel at different fuel/air equivalence ratios, ignition position and Pv. The results demonstrate that the magnitude of Pmax was increased corresponding to the increase of Pv- From the experiments,it is found that peak pressure with strong acoustic behaviour is observed related to increase in Pv and in some cases,significant detonation spike was also observed particularly in high burning velocity mixtures. It is found that substantial amount of unburnt gases left inside the vessel after the vent burst is the leading factor in increase of Pmax for high burning velocity mixtures at centrally ignited. The associate gas velocities ahead of the flame create high unburnt gas flows conditions at entry to the vent and this give rise to high back pressures which lead to the severity in final Pmax inside the vessel. It was observed that end ignition leads to a higher explosion severity than central ignition in most cases, implying that central ignition is not a worst-case scenario in gas vented explosions as reported previously.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Digital tillsynsteknik i djurhållning utomhus

I enlighet med Jordbruksverkets förfrågan behandlar denna rapport tre områden för digital teknik vid övervakning och kontroll av djur som vistas utomhus på stora ytor: (1) kamerateknologi, t.ex. användning av drönare, (2) positioneringsteknologi som GPS och (3) teknologi för att styra djurens rörelser, som drivning med drönare och användning av s.k. virtuella stängsel. De tre teknikområdena överlappar delvis varandra. Digital tillsyn av utegående djur är beroende av att sensorer mäter det man tror att de mäter med tillräcklig noggrannhet och att data kan överföras och bearbetas till information som lagras och analyseras på ett säkert och korrekt sätt. Sådana teknologier benämns med samlingsnamnet ’Precision Livestock Farming’ (PLF). Användningen av informationen är avgörande för teknikens användbarhet i tillsyns- och djurskyddsarbete. Tillämpningarna är till viss del reglerade av gällande lagstiftning, exempelvis genom krav på tillsyn, begränsad användning av elektricitet för att styra djurs beteende, användning av obemannade luftfarkoster, d.v.s. drönare, samt åtgärder för att förhindra att utrustning skadar djuren eller påverkar deras hälsa och beteende. Inom PLF används en rad olika sensorer som direkt eller indirekt kan mäta djurens miljö och djurens beteende och fysiologiska tillstånd. Den teknologiska utvecklingen har främst varit inriktad på mjölkkor, fjäderfän och grisar och endast i liten utsträckning berört häst, får och get. För djur på bete är överföringen av data från en enhet på eller vid djuret till en mottagare särskilt problematisk p.g.a. stora avstånd, men det sker en snabb teknisk utveckling mot effektivare överföring. PLF-teknologin innebär i de flesta fall att djuren övervakas kontinuerligt och att avvikelser i t.ex. deras hälsotillstånd och välfärd i princip kan upptäckas i realtid, vilket ska ställas mot nuvarande lagkrav på tillsyn minst en eller två gånger dagligen. Sensorer kan ge information om ett stort antal fysiologiska tillstånd och beteenden. En av de vanligaste teknikerna är sensorer för aktivitet. Indirekt kan de också ge information om idissling, liggtid, stegantal och ättid och utlösa larm om exempelvis brunst, hälsoproblem, hälta och kalvning. Sensorer kan även placeras i förmagen hos idisslare (s.k. våmbolus) där de mäter våm-pH och kan larma om störningar i magfunktionen, eller utformas som termometrar som kan larma om hälsostörningar, kalvning och vattenintag eller mikrofoner som kan mäta idissling och larma om brunst, kalvning och onormalt idisslingsmönster. Med kamerateknik kan man mäta aktivitet, kroppsform och hudtemperatur, vilket kan ge information om ketosstatus, hull, hälta och juverhälsa. Kameror monterade på drönare kan användas för att lokalisera och räkna djur, bestämma deras position, habitatval och till viss del deras beteende, särskilt när djuren rör sig över stora arealer. Det finns flera elektroniska positioneringsteknologier varav passiv ’Radio Frequency Identification RFID’ är den vanligaste. Räckvidden är kort med denna teknik men den kan vara användbar om man t.ex. vill mäta hur ofta djuren besöker en vattenpost. Andra teknologier kan med hjälp av antenner följa djurens positioner i realtid. GPS-enheter monterade i halsband kan regelbundet registrera djurens geografiska position. Användningen av GPS har blivit relativt vanlig i renskötseln vilket tycks ha lett till en förbättrad arbetssituation för renskötarna. Positionering med GPS ger inte alltid exakta uppgifter men tekniken har visat sig användbar för studier av habitatval, sociala interaktioner och gruppdynamik. Med positionerna från GPS har man också kunnat styra djur till områden med bättre betestillgång. Med en tillräckligt frekvent bestämning av position med hjälp av GPS (ca en gång per minut) är det möjligt att bestämma betestiden för nötkreatur på ett tillförlitligt sätt. En användning av drönare i djurskötsel och djurtillsyn kan vara att med hjälp av kamera lokalisera djuren över stora ytor. Denna användning begränsas dock av nuvarande bestämmelser om att föraren måste ha ögontakt med drönaren. I renskötseln har drönare börjat användas för att förflytta djur men denna tillämpning är ännu inte juridiskt reglerad. Virtuella stängsel är strukturer som bestäms med kartkoordinater eller elektronisk sändare på marken. Stängslen fungerar som inhägnader, hinder eller gränser. Djuren mottar signaler (vanligen ljud) och stimuli (vanligen elstötar från ett halsband) som gör det möjligt för dem att lära sig var stängslet finns. I vetenskapliga studier har man med varierande framgång lyckats lära djuren att associera ljudsignaler och elstötar med en gräns som inte får passeras. Förmågan att lära sig skiljer mellan olika djurslag, liksom mellan individer. Det finns fortfarande många obesvarade frågeställningar om hur djur kan anpassa sig till virtuella stängselsystemet, liksom hur de påverkas, både under inlärningsfas och bruksfas

Association of Factor V Leiden with Subsequent Atherothrombotic Events:A GENIUS-CHD Study of Individual Participant Data

BACKGROUND: Studies examining the role of factor V Leiden among patients at higher risk of atherothrombotic events, such as those with established coronary heart disease (CHD), are lacking. Given that coagulation is involved in the thrombus formation stage on atherosclerotic plaque rupture, we hypothesized that factor V Leiden may be a stronger risk factor for atherothrombotic events in patients with established CHD. METHODS: We performed an individual-level meta-analysis including 25 prospective studies (18 cohorts, 3 case-cohorts, 4 randomized trials) from the GENIUS-CHD (Genetics of Subsequent Coronary Heart Disease) consortium involving patients with established CHD at baseline. Participating studies genotyped factor V Leiden status and shared risk estimates for the outcomes of interest using a centrally developed statistical code with harmonized definitions across studies. Cox proportional hazards regression models were used to obtain age- and sex-adjusted estimates. The obtained estimates were pooled using fixed-effect meta-analysis. The primary outcome was composite of myocardial infarction and CHD death. Secondary outcomes included any stroke, ischemic stroke, coronary revascularization, cardiovascular mortality, and all-cause mortality. RESULTS: The studies included 69 681 individuals of whom 3190 (4.6%) were either heterozygous or homozygous (n=47) carriers of factor V Leiden. Median follow-up per study ranged from 1.0 to 10.6 years. A total of 20 studies with 61 147 participants and 6849 events contributed to analyses of the primary outcome. Factor V Leiden was not associated with the combined outcome of myocardial infarction and CHD death (hazard ratio, 1.03 [95% CI, 0.92-1.16]; I2=28%; P-heterogeneity=0.12). Subgroup analysis according to baseline characteristics or strata of traditional cardiovascular risk factors did not show relevant differences. Similarly, risk estimates for the secondary outcomes including stroke, coronary revascularization, cardiovascular mortality, and all-cause mortality were also close to identity. CONCLUSIONS: Factor V Leiden was not associated with increased risk of subsequent atherothrombotic events and mortality in high-risk participants with established and treated CHD. Routine assessment of factor V Leiden status is unlikely to improve atherothrombotic events risk stratification in this population

Subsequent Event Risk in Individuals with Established Coronary Heart Disease:Design and Rationale of the GENIUS-CHD Consortium

BACKGROUND: The "GENetIcs of sUbSequent Coronary Heart Disease" (GENIUS-CHD) consortium was established to facilitate discovery and validation of genetic variants and biomarkers for risk of subsequent CHD events, in individuals with established CHD. METHODS: The consortium currently includes 57 studies from 18 countries, recruiting 185,614 participants with either acute coronary syndrome, stable CHD or a mixture of both at baseline. All studies collected biological samples and followed-up study participants prospectively for subsequent events. RESULTS: Enrollment into the individual studies took place between 1985 to present day with duration of follow up ranging from 9 months to 15 years. Within each study, participants with CHD are predominantly of self-reported European descent (38%-100%), mostly male (44%-91%) with mean ages at recruitment ranging from 40 to 75 years. Initial feasibility analyses, using a federated analysis approach, yielded expected associations between age (HR 1.15 95% CI 1.14-1.16) per 5-year increase, male sex (HR 1.17, 95% CI 1.13-1.21) and smoking (HR 1.43, 95% CI 1.35-1.51) with risk of subsequent CHD death or myocardial infarction, and differing associations with other individual and composite cardiovascular endpoints. CONCLUSIONS: GENIUS-CHD is a global collaboration seeking to elucidate genetic and non-genetic determinants of subsequent event risk in individuals with established CHD, in order to improve residual risk prediction and identify novel drug targets for secondary prevention. Initial analyses demonstrate the feasibility and reliability of a federated analysis approach. The consortium now plans to initiate and test novel hypotheses as well as supporting replication and validation analyses for other investigators

Identification of 12 new susceptibility loci for different histotypes of epithelial ovarian cancer.

To identify common alleles associated with different histotypes of epithelial ovarian cancer (EOC), we pooled data from multiple genome-wide genotyping projects totaling 25,509 EOC cases and 40,941 controls. We identified nine new susceptibility loci for different EOC histotypes: six for serous EOC histotypes (3q28, 4q32.3, 8q21.11, 10q24.33, 18q11.2 and 22q12.1), two for mucinous EOC (3q22.3 and 9q31.1) and one for endometrioid EOC (5q12.3). We then performed meta-analysis on the results for high-grade serous ovarian cancer with the results from analysis of 31,448 BRCA1 and BRCA2 mutation carriers, including 3,887 mutation carriers with EOC. This identified three additional susceptibility loci at 2q13, 8q24.1 and 12q24.31. Integrated analyses of genes and regulatory biofeatures at each locus predicted candidate susceptibility genes, including OBFC1, a new candidate susceptibility gene for low-grade and borderline serous EOC

The chaotic rotation of elongated particles in anoscillating Couette ow

Flows with suspended particles occur in a large range of engineering applicationsand biological systems. A fundamental understanding of the uidparticlecoupling can be obtained by analyzing single particles in simple ow situations. Nilsen and Anderson (2013) studied the dynamics of a prolatespheroid rotating in the ow-gradient plane of an oscillating creepingshear ow. They found that given a high enough particle inertia the rotationcould become chaotic. This thesis extends on this work by taking uid inertia into account and studying the rotation of an elliptical cylinder.Numerical simulations with the Lattice Boltzmann EBF method reveal alarge variety of rotational states. Further, chaotic solutions are identiedwith a new Lyapunov exponent based algorithm. These chaotic solutionsare found to be present for heavy particles (compared to the uid) and smalloscillation frequencies (compared to the shear rate in the channel)

The chaotic rotation of elongated particles in anoscillating Couette ow

Flows with suspended particles occur in a large range of engineering applicationsand biological systems. A fundamental understanding of the uidparticlecoupling can be obtained by analyzing single particles in simple ow situations. Nilsen and Anderson (2013) studied the dynamics of a prolatespheroid rotating in the ow-gradient plane of an oscillating creepingshear ow. They found that given a high enough particle inertia the rotationcould become chaotic. This thesis extends on this work by taking uid inertia into account and studying the rotation of an elliptical cylinder.Numerical simulations with the Lattice Boltzmann EBF method reveal alarge variety of rotational states. Further, chaotic solutions are identiedwith a new Lyapunov exponent based algorithm. These chaotic solutionsare found to be present for heavy particles (compared to the uid) and smalloscillation frequencies (compared to the shear rate in the channel)