Quota hunting of Eurasian lynx in Norway: patterns of hunter selection,hunter efficiency and monitoring accuracy

Harvesting large carnivores is often a controversial issue and thus requires a higher precision than other types of recreational harvest. Despite this, management programmes are often initiated based on very limited knowledge about the state of the population and the composition and magnitude of the harvest. Here we analyse patterns of lynx harvest in Norway based on harvest data from 1994 to 2009. We found clear signs of sex-biased harvest rates, with males generally being more at risk. Further, harvest mortality rates increased with age among males but not among females. In general, the degree of quota filling was high, but there was a tendency for decreasing quota filling with increasing quotas. A population reconstruction of the Norwegian lynx population (1994–2004) based on a modified cohort analysis closely tracked the development in the official monitoring data, suggesting that the managers have access to relatively good information about the development of the population, at least at a larger spatial scale. Despite this, the population trajectory showed large temporal variation, and time lags in the management’s decision-making process are a likely cause of the observed patterns in the Norwegian lynx population.     

Effect of including genetic progress in milk yield on evaluating the use of sexed semen and other reproduction strategies in a dairy herd

The objective of this study was to explore the importance of including genetic progress in milk yield when evaluating different reproductive strategies in a dairy herd by simulation modeling. The model used in this study was SimHerd V, a dynamic and mechanistic Monte Carlo simulation model of a dairy herd including young stock. A daily increasing trend describing genetic milk yield potential of the sire population was included in the model. The inaccuracy of assuming that replacement heifers have the same (milk yield) potential as the cows present in the herd was hereby dealt with. Improving estrus detection rate from 0.45 to 0.80 increased gross margin (GM) per cow-year by €20 when genetic progress was not included in the model. When genetic progress was included in the model, then the same improvement in estrus detection decreased the GM per cow-year by €7.4. This reduced effect was explained by a lower replacement rate in consequence of the improved estrus detection and thereby a slower genetic progress in the herd. There was a reduced effect of including genetic progress on GM when surplus heifers were sold selectively based on breeding values. Repeated insemination with sexed semen on the superior half of all heifers reduced GM by €8 per cow-year when genetic progress was not included and increased the GM by €16 per cow-year when genetic progress was included in the model. Including genetic progress reduced the losses caused by lower conception and estrus detection rates and had a minimal effect with regard to postponing first insemination. This study has proven that it is important to include genetic progress in decisions on reproduction strategies in a dairy herd.     

Seventy years of changes in the abundance of Danish charophytes

相似文献   

Large-scale bioreactor production of the herbicide-degrading Aminobacter sp. strain MSH1

The Aminobacter sp. strain MSH1 has potential for pesticide bioremediation because it degrades the herbicide metabolite 2,6-dichlorobenzamide (BAM). Production of the BAM-degrading bacterium using aerobic bioreactor fermentation was investigated. A mineral salt medium limited for carbon and with an element composition similar to the strain was generated. The optimal pH and temperature for strain growth were determined using shaker flasks and verified in bioreactors. Glucose, fructose, and glycerol were suitable carbon sources for MSH1 (μ?=?0.1 h^?1); slower growth was observed on succinate and acetic acid (μ?=?0.01 h^?1). Standard conditions for growth of the MSH1 strain were defined at pH 7 and 25 °C, with glucose as the carbon source. In bioreactors (1 and 5 L), the specific growth rate of MSH1 increased from μ?=?0.1 h^?1 on traditional mineral salt medium to μ?=?0.18 h^?1 on the optimized mineral salt medium. The biomass yield under standard conditions was 0.47 g dry weight biomass/g glucose consumed. An investigation of the catabolic capacity of MSH1 cells harvested in exponential and stationary growth phases showed a degradation activity per cell of about 3?×?10^?9 μg BAM h^?1. Thus, fast, efficient, large-scale production of herbicide-degrading Aminobacter was possible, bringing the use of this bacterium in bioaugmentation field remediation closer to reality.     

Different contributions of HtrA protease and chaperone activities to Campylobacter jejuni stress tolerance and physiology

The microaerophilic bacterium Campylobacter jejuni is the most common cause of bacterial food-borne infections in the developed world. Tolerance to environmental stress relies on proteases and chaperones in the cell envelope, such as HtrA and SurA. HtrA displays both chaperone and protease activities, but little is known about how each of these activities contributes to stress tolerance in bacteria. In vitro experiments showed temperature-dependent protease and chaperone activities of C. jejuni HtrA. A C. jejuni mutant lacking only the protease activity of HtrA was used to show that the HtrA chaperone activity is sufficient for growth at high temperature or under oxidative stress, whereas the HtrA protease activity is essential only under conditions close to the growth limit for C. jejuni. However, the protease activity was required to prevent induction of the cytoplasmic heat shock response even under optimal growth conditions. Interestingly, the requirement of HtrA at high temperatures was found to depend on the oxygen level, and our data suggest that HtrA may protect oxidatively damaged proteins. Finally, protease activity stimulates HtrA production and oligomer formation, suggesting that a regulatory role depends on the protease activity of HtrA. Studying a microaerophilic organism encoding only two known periplasmic chaperones (HtrA and SurA) revealed an efficient HtrA chaperone activity and proposed multiple roles of the protease activity, increasing our understanding of HtrA in bacterial physiology.     

Characterization of mutations in the GTP-binding domain of IF2 resulting in cold-sensitive growth of Escherichia coli

The infB gene encodes translation initiation factor IF2. We have determined the entire sequence of infB from two cold-sensitive Escherichia coli strains IQ489 and IQ490. These two strains have been isolated as suppressor strains for the temperature-sensitive secretion mutation secY24. The mutations causing the suppression phenotype are located within infB. The only variations from the wild-type (wt) infB found in the two mutant strains are a replacement of Asp409 with Glu in strain IQ489 and an insertion of Gly between Ala421 and Gly422 in strain IQ490. Both positions are located in the GTP-binding G-domain of IF2. A model of the G-domain of E.coli IF2 is presented in. Physiological quantities of the recombinant mutant proteins were expressed in vivo in E.coli strains from which the chromosomal infB gene has been inactivated. At 42 degrees C, the mutants sustained normal cell growth, whereas a significant decrease in growth rate was found at 25 degrees C for both mutants as compared to wt IF2 expressed in the control strain. Circular dichroism spectra were recorded of the wt and the two mutant proteins to investigate the structural properties of the proteins. The spectra are characteristic of alpha-helix dominated structure, and reveal a significant different behavior between the wt and mutant IF2s with respect to temperature-induced conformational changes. The temperature-induced conformational change of the wt IF2 is a two-state process. In a ribosome-dependent GTPase assay in vitro the two mutants showed practically no activity at temperatures below 10 degrees C and a reduced activity at all temperatures up to 45 degrees C, as compared to wt IF2. The results indicate that the amino acid residues, Asp409 and Gly422, are located in important regions of the IF2 G-domain and demonstrate the importance of GTP hydrolysis in translation initiation for optimal cell growth.