Alternative operation models for using a feed‐in terminal as a part of the forest chip supply system for a CHP plant

The fuel supply of forest chips has to adapt to the annual fluctuations of power and heat generation. This creates inefficiency and unbalances the capacity utilization of the fuel supply fleet in the direct fuel supplies from roadside storages to power and heat generation. Terminals can offer an alternative approach for the fleet management of fuel supplies in terms of smoothing the unbalanced fleet use towards more even year‐round operations. The aim of the study was to compare the supply costs of a conventional direct forest chip supply to an alternative fuel supply with the use of a feed‐in terminal using the discrete‐event simulation method. The influences of the terminal location, terminal investment cost, outbound terminal transport method, terminal truck utilization and quality changes of terminal‐stored forest chips for the fuel supply cost were studied in the case environment. By introducing a feed‐in terminal and a shuttle truck for the transports of terminal‐stored forest chips, the total supply cost was 1.4% higher than the direct fuel supply scenario. In terminal scenarios, the supply costs increased 1–2% if the cost of the terminal investment increased 30%, the distance to the terminal increased from 5 to 30 km or the total annual use of a terminal truck decreased 1500 h. Moreover, a 1 per cent point per month increase in the dry matter loss of terminal‐stored chips increased the total supply cost 1%. The study revealed that with the relatively low additional cost, the feed‐in terminal can be introduced to the conventional forest chip supply. Cost compensation can be gained through the higher annual use of a fuel supply fleet and more secured fuel supply to power plants by decreasing the need for supplement fuel, which can be more expensive at a time of the highest fuel demand.     

Odonates,gregarines and water mites: why are the same host species infected by both parasites?

1. Damselflies and dragonflies are widely parasitised insects and numerous studies have tried to understand this host–parasite relationship. However, most of these studies have concentrated on a single host species, neglecting the larger pattern within the Odonata order. 2. The aim of this paper was to examine different damselfly and dragonfly species for common endo‐ and ectoparasites and whether a general infection pattern can be found. Additionally, the goal was to investigate whether the phylogeny of the host species could explain these possible infection patterns. To this end, a dataset from the existing literature was compiled and the prevalence of endoparasitic gregarines and ectoparasitic water mites was analysed for 46 different odonate species. 3. Three distinct patterns were found: (i) most of the odonate host species had both gregarines and water mites, rather than only either one or neither; (ii) there appears to be a positive association between gregarine and water mite prevalences across host species; (iii) a weak phylogenetic signal was detected in gregarine prevalence and a strong one in water mite prevalence. 4. It is hypothesised that, due to the infection and transmission mechanisms by which water mites and gregarines infect different odonate host species, parasitism is aggregated to common, high‐density species. However, much research is needed in order to fully understand this relationship between odonates and their parasites, especially within the same host populations and host species assemblages.     

Environmental variability and population dynamics: do European and North American ducks play by the same rules?

Density dependence, population regulation, and variability in population size are fundamental population processes, the manifestation and interrelationships of which are affected by environmental variability. However, there are surprisingly few empirical studies that distinguish the effect of environmental variability from the effects of population processes. We took advantage of a unique system, in which populations of the same duck species or close ecological counterparts live in highly variable (north American prairies) and in stable (north European lakes) environments, to distinguish the relative contributions of environmental variability (measured as between‐year fluctuations in wetland numbers) and intraspecific interactions (density dependence) in driving population dynamics. We tested whether populations living in stable environments (in northern Europe) were more strongly governed by density dependence than populations living in variable environments (in North America). We also addressed whether relative population dynamical responses to environmental variability versus density corresponded to differences in life history strategies between dabbling (relatively “fast species” and governed by environmental variability) and diving (relatively “slow species” and governed by density) ducks. As expected, the variance component of population fluctuations caused by changes in breeding environments was greater in North America than in Europe. Contrary to expectations, however, populations in more stable environments were not less variable nor clearly more strongly density dependent than populations in highly variable environments. Also, contrary to expectations, populations of diving ducks were neither more stable nor stronger density dependent than populations of dabbling ducks, and the effect of environmental variability on population dynamics was greater in diving than in dabbling ducks. In general, irrespective of continent and species life history, environmental variability contributed more to variation in species abundances than did density. Our findings underscore the need for more studies on populations of the same species in different environments to verify the generality of current explanations about population dynamics and its association with species life history.     

Offspring phenotype is shaped by the nonsperm fraction of semen

In a large majority of animal species, the only contribution of males to the next generation has been assumed to be their genes (sperm). However, along with sperm, seminal plasma contains a wide array of extracellular factors that have many important functions in reproduction. Yet, the potential intergenerational effects of these factors are virtually unknown. We investigated these effects in European whitefish (Coregonus lavaretus) by experimentally manipulating the presence and identity of seminal plasma and by fertilizing the eggs of multiple females with the manipulated and unmanipulated semen of several males in a full‐factorial breeding design. The presence of both own seminal plasma and foreign seminal plasma inhibited sperm motility, and the removal of own seminal plasma decreased embryo survival. Embryos hatched significantly earlier after both semen manipulations than in control fertilizations; foreign seminal plasma also increased offspring aerobic swimming performance. Given that our experimental design allowed us to control potentially confounding sperm‐mediated (sire) effects and maternal effects, our results indicate that seminal plasma may have direct intergenerational consequences for offspring phenotype and performance. This novel source of offspring phenotypic variance may provide new insights into the evolution of polyandry and mechanisms that maintain heritable variation in fitness and associated female mating preferences.     

Lakes as nitrous oxide sources in the boreal landscape

Estimates of regional and global freshwater N₂O emissions have remained inaccurate due to scarce data and complexity of the multiple processes driving N₂O fluxes the focus predominantly being on summer time measurements from emission hot spots, agricultural streams. Here, we present four‐season data of N₂O concentrations in the water columns of randomly selected boreal lakes covering a large variation in latitude, lake type, area, depth, water chemistry, and land use cover. Nitrate was the key driver for N₂O dynamics, explaining as much as 78% of the variation of the seasonal mean N₂O concentrations across all lakes. Nitrate concentrations varied among seasons being highest in winter and lowest in summer. Of the surface water samples, 71% were oversaturated with N₂O relative to the atmosphere. Largest oversaturation was measured in winter and lowest in summer stressing the importance to include full year N₂O measurements in annual emission estimates. Including winter data resulted in fourfold annual N₂O emission estimates compared to summer only measurements. Nutrient‐rich calcareous and large humic lakes had the highest annual N₂O emissions. Our emission estimates for Finnish and boreal lakes are 0.6 and 29 Gg N₂O‐N/year, respectively. The global warming potential of N₂O from lakes cannot be neglected in the boreal landscape, being 35% of that of diffusive CH₄ emission in Finnish lakes.     

Genetic Markers Enhance Coronary Risk Prediction in Men: The MORGAM Prospective Cohorts

Background

More accurate coronary heart disease (CHD) prediction, specifically in middle-aged men, is needed to reduce the burden of disease more effectively. We hypothesised that a multilocus genetic risk score could refine CHD prediction beyond classic risk scores and obtain more precise risk estimates using a prospective cohort design.

Methods

Using data from nine prospective European cohorts, including 26,221 men, we selected in a case-cohort setting 4,818 healthy men at baseline, and used Cox proportional hazards models to examine associations between CHD and risk scores based on genetic variants representing 13 genomic regions. Over follow-up (range: 5–18 years), 1,736 incident CHD events occurred. Genetic risk scores were validated in men with at least 10 years of follow-up (632 cases, 1361 non-cases). Genetic risk score 1 (GRS1) combined 11 SNPs and two haplotypes, with effect estimates from previous genome-wide association studies. GRS2 combined 11 SNPs plus 4 SNPs from the haplotypes with coefficients estimated from these prospective cohorts using 10-fold cross-validation. Scores were added to a model adjusted for classic risk factors comprising the Framingham risk score and 10-year risks were derived.

Results

Both scores improved net reclassification (NRI) over the Framingham score (7.5%, p = 0.017 for GRS1, 6.5%, p = 0.044 for GRS2) but GRS2 also improved discrimination (c-index improvement 1.11%, p = 0.048). Subgroup analysis on men aged 50–59 (436 cases, 603 non-cases) improved net reclassification for GRS1 (13.8%) and GRS2 (12.5%). Net reclassification improvement remained significant for both scores when family history of CHD was added to the baseline model for this male subgroup improving prediction of early onset CHD events.

Conclusions

Genetic risk scores add precision to risk estimates for CHD and improve prediction beyond classic risk factors, particularly for middle aged men.     

The effect of land use change on the vascular plant species turnover in boreal lakes

The effects of different land use types on nutrient and chemical run-off have been widely researched, but the total effect of change in land use on the aquatic species community is not well-known. For this study we researched the effect of land use change on the vascular plant communities in lakes. The study was conducted with aerial photographs and GIS-techniques in the countryside of central Finland. We compared the change in vascular plant species community structure with the change in land use around 25 lakes, between the years 1933–1934 and 1996. The change in land use was analyzed in two different riparian zones. We found several indications of links between changes in land use and aquatic vascular plant species. According to our data a decrease in agricultural land use, in particular fields and meadows, appears to influence species turnover and increases the number of new vascular plant species. When the changes in fields and meadows were added together and compared to the change in species turnover, the correlation was even more evident. Changes in land use types in a zone 0–100 m from the lake shoreline correlated with a change in vascular plant species more often than changes in a larger, adjacent zone, 100–400 m from the shore. This indicates that changes in the few hundred meters nearest the lake have the most elemental consequences for aquatic vascular plant species, giving an indication of the breadth of the protection zones needed between freshwaters and agricultural lands.     

Insulin‐ and Exercise‐Stimulated Skeletal Muscle Blood Flow and Glucose Uptake in Obese Men

Objective: Insulin resistance in obese subjects results in the impaired use of glucose by insulin‐sensitive tissues, e.g., skeletal muscle. In the present study, we determined whether insulin resistance in obesity is associated with an impaired ability of exercise to stimulate muscle blood flow, oxygen delivery, or glucose uptake. Research Methods and Procedures: Nine obese (body mass index = 36 ± 2 kg/m²) and 11 age‐matched nonobese men (body mass index = 22 ± 1 kg/m²) performed one‐legged isometric exercise during hyperinsulinemia. Rates of femoral muscle blood flow, oxygen consumption, and glucose uptake were measured simultaneously in both legs using [¹⁵O]H₂O, [¹⁵O]O₂, [¹⁸F]fluoro‐deoxy‐glucose, and positron emission tomography. Results: The obese subjects exhibited resistance to insulin stimulation of glucose uptake in resting muscle, regardless of whether glucose uptake was expressed per kilogram of femoral muscle mass (p = 0.001) or per the total mass of quadriceps femoris muscle. At similar workloads, oxygen consumption, blood flow, and glucose uptake were lower in the obese than the nonobese subjects when expressed per kilogram of muscle, but similar when expressed per quadriceps femoris muscle mass. Discussion: We conclude that obesity is characterized by insulin resistance of glucose uptake in resting skeletal muscle regardless of how glucose uptake is expressed. When compared with nonobese individuals at similar absolute workloads and under identical hyperinsulinemic conditions, the ability of exercise to increase muscle oxygen uptake, blood flow, and glucose uptake per muscle mass is blunted in obese insulin‐resistant subjects. However, these defects are compensated for by an increase in muscle mass.     

Proliferation, oxidative stress and cell death in cells exposed to 872 MHz radiofrequency radiation and oxidants

Human SH-SY5Y neuroblastoma and mouse L929 fibroblast cells were exposed to 872 MHz radiofrequency (RF) radiation using continuous waves (CW) or a modulated signal similar to that emitted by GSM mobile phones at a specific absorption rate (SAR) of 5 W/kg in isothermal conditions. To investigate possible combined effects with other agents, menadione was used to induce reactive oxygen species, and tert-butylhydroperoxide (t-BOOH) was used to induce lipid peroxidation. After 1 or 24 h of exposure, reduced cellular glutathione levels, lipid peroxidation, proliferation, caspase 3 activity, DNA fragmentation and viability were measured. Two statistically significant differences related to RF radiation were observed: Lipid peroxidation induced by t-BOOH was increased in SH-SY5Y (but not in L929) cells, and menadione-induced caspase 3 activity was increased in L929 (but not in SH-SY5Y) cells. Both differences were statistically significant only for the GSM-modulated signal. The other end points were not significantly affected in any of the experimental conditions, and no effects were observed from exposure to RF radiation alone. The positive findings may be due to chance, but they may also reflect effects that occur only in cells sensitized by chemical stress. Further studies are required to investigate the reproducibility and dose response of the possible effects.