Long-term trends in water temperature and ice cover in the subalpine lake, Øvre Heimdalsvatn,and nearby lakes and rivers

Long-term data series of ice cover on lakes and river temperatures from the mountain areas of Norway are lacking. The present study analyses the last four decades of ice data from the subalpine lake, Øvre Heimdalsvatn, and water temperature data from its outlet river, Hinøgla. These data are compared to water temperature data from three neighbouring, quite different locations, the glacier-fed rivers Leirungsåi and Sjoa, and the alpine lake, Bessvatn. The study also examines the air temperature/river temperature relationships, and the air temperature/ice freeze-up and break-up dates. During the months of July, August and September, the water temperature in Hinøgla was well correlated to the air temperature, but the correlation was poor in the remaining months due to the ice cover and snow conditions. A significant temperature increase of 2–3°C has been observed in Hinøgla in the months August–October since 1984. There were only minor changes in the duration of the ice cover season during the last 40 years, but a delay of 9 days was found in the freeze-up date and a delay of 6 days in the break-up date, although the latter was not significant.     

Changes in the Intestinal Microbiota of Wild Atlantic cod Gadus morhua L. Upon Captive Rearing

The commensal microbiota plays an important role in the well-being of the host organism, and it would be worthwhile to know the tenacious communities among them. Therefore, a study was undertaken to examine the changes in constitution of the intestinal microbiota of wild fish consequential to captivity. At first, the composition of intestinal microorganisms of Atlantic cod caught from the coastal area off Bod?, Norway, was examined. Thereafter, the changes in the bacterial community of the captive fish after offering them artificial feed or subjecting them to starvation were studied. The microbiota from the intestinal contents and wall segments were analyzed quantitatively by spread plate technique and DAPI staining and qualitatively by denaturing gradient gel electrophoresis. The study revealed that the counts of intestinal microbes in wild-caught Atlantic cod were not affected by captive rearing for 6?weeks, either when fed or when starved. However, the diversity of intestinal bacterial community was reduced in response to artificial feeding, whereas the change was restricted upon starvation.     

Molecular modelling and simulations in cancer research

The complexity of cancer and the vast amount of experimental data available have made computer-aided approaches necessary. Biomolecular modelling techniques are becoming increasingly easier to use, whereas hardware and software are becoming better and cheaper. Cross-talk between theoretical and experimental scientists dealing with cancer-research from a molecular approach, however, is still uncommon. This is in contrast to other fields, such as amyloid-related diseases, where molecular modelling studies are widely acknowledged. The aim of this review paper is therefore to expose some of the more common approaches in molecular modelling to cancer scientists in simple terms, illustrating success stories while also revealing the limitations of computational studies at the molecular level.     

Measuring effects of linear obstacles on wildlife movements: accounting for the relationship between step length and crossing probability

Animal movements in the landscape are influenced by linear features such as rivers, roads and power lines. Prior studies have investigated how linear features, particularly roads, affect movement rates by comparing animal's movement rate measured as step lengths (i.e., the distance between consecutive observations such as GPS locations) before, during and after crossing of a linear feature. The null hypothesis has been that the length of crossing steps should not differ from other steps, and a deviation from this, mainly that steps are longer during crossing, has been taken as support for a disturbance effect of the linear feature. However, based on the simple relationship between the length of a step and its probability to cross a linear feature, we claim that this assumption is inappropriate to test for behavioural responses to linear features. The probability is related to the proportion of the total length of the trajectory (i.e., the path of movement) a step constitutes. Consequently, care should be taken when formulating hypotheses about how animal moves in relation to linear features in the landscape. Statistical tests should be set up with respect to the expected length based on the distribution of step lengths in the trajectory. We propose two methods that accounts for the bias in crossing frequency that is caused by step lengths, and illustrates their applications by using simulated animal trajectories as well as empirical data on reindeer in an area with a power line.     

Hearing in reindeer (Rangifer tarandus)

The audiogram of two yearling male reindeer (Rangifer tarandus tarandus) were determined using a conditioned suppression/avoidance procedure. During testing, the animal was drinking from a metal bowl while pure tone signals were played at random intervals and followed by an electric shock in the bowl. By breaking contact with the bowl at sound signals, the animal avoided the shock. The animals detected sounds at intensities of 60 dB or less from 70 Hz to 38 kHz. The frequency range of best sensitivity was relatively flat from 1 kHz to 16 kHz, with a best sensitivity of 3 dB at 8 kHz. The hearing ability of reindeer is similar to the hearing ability of other ungulates.