Effect of high elevation birch forest on snow stability

Forest and especially evergreen conifers like pine and spruce are known to reduce avalanche formation due to their physical anchoring effect and their influence on snow pack layering through changed temperature, radiation, wind speed etc. Research shows that percentage covered by the crown reflects the forests ability to reduce avalanche danger, and crown cover is therefore often used as a measure of the forest's efficiency as protection forest. Crown cover is highest in evergreen conifer forests, but in Scandinavia, the deciduous tree species birch (Betula pubsens, subspecies alpine betula) is the most common tree species in higher elevations near the tree line. This is a small and often thin stemmed, flexible tree. Their crown is thin and field observations show that in avalanche terrain the stems of such trees have a form heavily affected by snow creep and glide and the trees are in many cases bent under the snow cover. Thus, this type of forest does not fulfill the common criteria set for protection forests and its effect on the snow cover is largely unknown. In this study we question whether typical birch forests can reduce the probability of avalanche formation through snowpack effects and anchoring. We look at cases of small avalanches in birch forest, stem densities and snow profiles inside and outside birch forest and compare observations to results from models for calculating anchoring effects

Use of Daisybell and Snow Profiles to Investigate the Effect of Alpine Birch on Avalanche Release

Through a field study in Abisko, northern Sweden, we have used the artificial avalanche release system DaisyBell together with snow profiles to study the effect of alpine birch forest on avalanche formation. Evergreen conifers have long been known to reduce avalanche formation probability, however, in Scandinavia, the small birch type Alpine betula is the most common tree species in mountainous regions. Its effect on snow stability has been unknown, but of crucial importance for backcountry recreationists and for housing and mountain cabin planning. This paper presents the results from the field campaign. We show that triggering of avalanches was much more successful in open terrain than inside the birch forest. Crack propagation was significantly hindered in vicinity of trees and the snow pack layering differed to a large degree when moving few meters from inside the forest to open terrain nearby. The use of DaisyBell inside forest is novel, and experience with this practice can also be transferred to other types of demanding terrain

Intrinsic aerobic capacity sets a divide for aging and longevity

<p><b>Rationale:</b> Low aerobic exercise capacity is a powerful predictor of premature morbidity and mortality for healthy adults as well as those with cardiovascular disease. For aged populations, poor performance on treadmill or extended walking tests indicates closer proximity to future health declines. Together, these findings suggest a fundamental connection between aerobic capacity and longevity.</p> <p><b>Objectives:</b> Through artificial selective breeding, we developed an animal model system to prospectively test the association between aerobic exercise capacity and survivability (aerobic hypothesis).</p> <p><b>Methods and Results:</b> Laboratory rats of widely diverse genetic backgrounds (N:NIH stock) were selectively bred for low or high intrinsic (inborn) treadmill running capacity. Cohorts of male and female rats from generations 14, 15, and 17 of selection were followed for survivability and assessed for age-related declines in cardiovascular fitness including maximal oxygen uptake (VO<sub>2max</sub>), myocardial function, endurance performance, and change in body mass. Median lifespan for low exercise capacity rats was 28% to 45% shorter than high capacity rats (hazard ratio, 0.06; P<0.001). VO<sub>2max</sub>, measured across adulthood was a reliable predictor of lifespan (P<0.001). During progression from adult to old age, left ventricular myocardial and cardiomyocyte morphology, contractility, and intracellular Ca<sup>2+</sup> handling in both systole and diastole, as well as mean blood pressure, were more compromised in rats bred for low aerobic capacity. Physical activity levels, energy expenditure (Vo<sub>2</sub>), and lean body mass were all better sustained with age in rats bred for high aerobic capacity.</p> <p><b>Conclusions:</b> These data obtained from a contrasting heterogeneous model system provide strong evidence that genetic segregation for aerobic exercise capacity can be linked with longevity and are useful for deeper mechanistic exploration of aging.</p&gt

Snøskred i bjørkeskog - testforsøk i Abisko

Det er utført forsøk med DaisyBell i Abisko for å studere utløsning av snøskred i bjørkeskog. Bakgrunnen er blant annet at mange løsneområder for snøskred er delvis gjengrodd og en ønsker å ha et generelt grunnlag for hvordan snøskredfare i skog og særlig bjørkeskog vurderes i forhold til bebyggelse.Prosjektet er finansiert av NGI, NVE og NIFS og utført av NGI. Rapporten inngår i Skog og Skred-prosjektet til NGI og NVE som er oppsummert i NGI-rapport 20120078-01-R - Forslag til kriterier for vernskog mot skre

The Effect of Exercise Training on Myocardial and Skeletal Muscle Metabolism by MR Spectroscopy in Rats with Heart Failure

The metabolism and performance of myocardial and skeletal muscle are impaired in heart failure (HF) patients. Exercise training improves the performance and benefits the quality of life in HF patients. The purpose of the present study was to determine the metabolic profiles in myocardial and skeletal muscle in HF and exercise training using MRS, and thus to identify targets for clinical MRS in vivo. After surgically establishing HF in rats, we randomized the rats to exercise training programs of different intensities. After the final training session, rats were sacrificed and tissues from the myocardial and skeletal muscle were extracted. Magnetic resonance spectra were acquired from these extracts, and principal component and metabolic enrichment analysis were used to assess the differences in metabolic profiles. The results indicated that HF affected myocardial metabolism by changing multiple metabolites, whereas it had a limited effect on skeletal muscle metabolism. Moreover, exercise training mainly altered the metabolite distribution in skeletal muscle, indicating regulation of metabolic pathways of taurine and hypotaurine metabolism and carnitine synthesis

Coastal inundation multi-hazard analysis for a construction site in Malaysia

-Establishment of new manufacturing sites in high-technology industries requires considerable investments. These investments need to be safeguarded against the impacts of natural hazards. The March 2011 Tohoku earthquake and tsunami highlighted the tremendous impacts of cascading hazards and emphasised the importance of hazard and risk assessment in the early stages of site selection. A screening study of coastal inundation due to multiple hazards was performed for a potential manufacturing plant at the Batu Kawan Industrial Park in Penang state, Malaysia. The analysis accounted for river floods, rainfall and flash floods, cyclones, tides, storm surges, sea-level rise, and tsunamis. Natural hazards not related to inundation, such as earthquakes and volcanoes, were also briefly evaluated. Where relevant data were available, the hazards were assessed quantitatively. Otherwise, they were assessed qualitatively. The effects of climate changes were discussed for temperature and rainfall and for sea-level rise. The proposed development site elevation of 2.60 m LSD (Land Survey Data Level; 30 cm above mean sea level) will probably be reached by both the 100-year flood and the 100-year combined tide and storm surge. With a well-engineered drainage system the flooding risk is low, but in this low-lying area coincidence with a storm surge or high tide will aggravate the flooding situation. Sea-level rise over the next 100 years for the region is assumed to be less than 0.55 m. The relative levels for the other hazards were found to be lower. There is obviously significant uncertainty associated with the estimated hazard at the return periods considered for design. A further comparison of the various hazard levels is not meaningful without considering also the consequences (i.e. the risk)

Skeletal muscle metabolism in rats with low and high intrinsic aerobic capacity: Effect of aging and exercise training

Purpose Exercise training increases aerobic capacity and is beneficial for health, whereas low aerobic exercise capacity is a strong independent predictor of cardiovascular disease and premature death. The purpose of the present study was to determine the metabolic profiles in a rat model of inborn low versus high capacity runners (LCR/HCR) and to determine the effect of inborn aerobic capacity, aging, and exercise training on skeletal muscle metabolic profile. Methods LCR/HCR rats were randomized to high intensity low volume interval treadmill training twice a week or sedentary control for 3 or 11 months before they were sacrificed, at 9 and 18 months of age, respectively. Magnetic resonance spectra were acquired from soleus muscle extracts, and partial least square discriminative analysis was used to determine the differences in metabolic profile. Results Sedentary HCR rats had 54% and 30% higher VO compared to sedentary LCR rats at 9 months and 18 months, respectively. In HCR, exercise increased running speed significantly, and VO was higher at age of 9 months, compared to sedentary counterparts. In LCR, changes were small and did not reach the level of significance. The metabolic profile was significantly different in the LCR sedentary group compared to the HCR sedentary group at the age of 9 and 18 months, with higher glutamine and glutamate levels (9 months) and lower lactate level (18 months) in HCR. Irrespective of fitness level, aging was associated with increased soleus muscle concentrations of glycerophosphocholine and glucose. Interval training did not influence metabolic profiles in LCR or HCR rats at any age. Conclusion Differences in inborn aerobic capacity gave the most marked contrasts in metabolic profile, there were also some changes with ageing. Low volume high intensity interval training twice a week had no detectable effect on metabolic profile

Gene expression profiling of skeletal muscle in exercise-trained and sedentary rats with inborn high and low VO2max

The relationship between inborn maximal oxygen uptake (VO2max) and skeletal muscle gene expression is unknown. Since low VO2max is a strong predictor of cardiovascular mortality, genes related to low VO2max might also be involved in cardiovascular disease. To establish the relationship between inborn VO2max and gene expression, we performed microarray analysis of the soleus muscle of rats artificially selected for high- and low running capacity (HCR and LCR, respectively). In LCR, a low VO2max was accompanied by aggregation of cardiovascular risk factors similar to the metabolic syndrome. Although sedentary HCR were able to maintain a 120% higher running speed at VO2max than sedentary LCR, only three transcripts were differentially expressed (FDR ≤ 0.05) between the groups. Sedentary LCR expressed high levels of a transcript with strong homology to human leucyl-transfer RNA synthetase, of whose overexpression has been associated with a mutation linked to mitochondrial dysfunction. Moreover, we studied exercise-induced alterations in soleus gene expression, since accumulating evidence indicates that long-term endurance training has beneficial effects on the metabolic syndrome. In terms of gene expression, the response to exercise training was more pronounced in HCR than LCR. HCR upregulated several genes associated with lipid metabolism and fatty acid elongation, whereas LCR upregulated only one transcript after exercise training. The results indicate only minor differences in soleus muscle gene expression between sedentary HCR and LCR. However, the inborn level of fitness seems to influence the transcriptional adaption to exercise, as more genes were upregulated after exercise training in HCR than LCR

Exercise training reveals micro-RNAs associated with improved cardiac function and electrophysiology in rats with heart failure after myocardial infarction

Aims: Endurance training improves aerobic fitness and cardiac function in individuals with heart failure. However, the underlying mechanisms are not well characterized. Exercise training could therefore act as a tool to discover novel targets for heart failure treatment. We aimed to associate changes in Ca handling and electrophysiology with micro-RNA (miRNA) profile in exercise trained heart failure rats to establish which miRNAs induce heart failure-like effects in Ca handling and electrophysiology. Methods and results: Post-myocardial infarction (MI) heart failure was induced in Sprague Dawley rats. Rats with MI were randomized to sedentary control (sed), moderate (mod)- or high-intensity (high) endurance training for 8 weeks. Exercise training improved cardiac function, Ca handling and electrophysiology including reduced susceptibility to arrhythmia in an exercise intensity-dependent manner where high intensity gave a larger effect. Fifty-five miRNAs were significantly regulated (up or down) in MI-sed, of which 18 and 3 were changed towards Sham-sed in MI-high and MI-mod, respectively. Thereafter we experimentally altered expression of these “exercise-miRNAs” individually in human induced pluripotent stem cell-derived cardiomyocytes (hIPSC-CM) in the same direction as they were changed in MI. Of the “exercise-miRNAs”, miR-214-3p prolonged AP duration, whereas miR-140 and miR-208a shortened AP duration. miR-497-5p prolonged Ca release whereas miR-214-3p and miR-31a-5p prolonged Ca decay. Conclusion: Using exercise training as a tool, we discovered that miR-214-3p, miR-497-5p, miR-31a-5p contribute to heart-failure like behaviour in Ca handling and electrophysiology and could be potential treatment targets