579 research outputs found
Management of wolf and lynx conflicts with human interests
In many areas viable populations of large carnivores are political goals. One of the most important factors in order to achieve viable large carnivore populations is human tolerance for presence of large carnivores. Thus, management of large carnivore populations in multi use landscapes will involve mitigating conflicts with human interests. In order to mitigate conflicts in a effective way, managers need tools for predicting likelihood of large carnivore occurrence, knowledge on which conflicts are considered as most important by humans in different areas, and the most efficient ways of mitigating the experienced problems. The aim of this thesis is to contribute to some parts of this toolbox for large carnivore managers. A habitat suitability model, with density of roads and built up areas as the most important variables, classified 79% of Scandinavia outside the reindeer husbandry area as suitable wolf habitat. Human tolerance towards wolves was lowest inside wolf territories and slowly increased amongst residents living up to 200 km from the nearest wolf territory. Human tolerance towards wolves may however be affected by mitigation measures such as subsidising electric fences in order to reduce the risk of wolf depredation on livestock. Management actions as subsidies for pro active measures or predator control should be targeting specific areas or individuals in order to be effective. It is also important to use the ârightâ management actions at the right time. Therefore it is, among other things, important to know if a reported bold wolf is acting in a way that most wolves would not, given the same circumstances. Wolves moved away from an approaching human on average at a distance of about 100 m. Wind velocity and wind direction influenced the distance heavily and humans may come as close to wolves as 17 meters before the wolves become aware of the human and react
Effects of Intercellular Junction Protein Expression on Intracellular Ice Formation in Mouse Insulinoma Cells
AbstractThe development of cryopreservation procedures for tissues has proven to be difficult in part because cells within tissue are more susceptible to intracellular ice formation (IIF) than are isolated cells. In particular, previous studies suggest that cell-cell interactions increase the likelihood of IIF by enabling propagation of ice between neighboring cells, a process thought to be mediated by gap junction channels. In this study, we investigated the effects of cell-cell interactions on IIF using three genetically modified strains of the mouse insulinoma cell line MIN6, each of which expressed key intercellular junction proteins (connexin-36, E-cadherin, and occludin) at different levels. High-speed video cryomicroscopy was used to visualize the freezing process in pairs of adherent cells, revealing that the initial IIF event in a given cell pair was correlated with a hitherto unrecognized precursor phenomenon: penetration of extracellular ice into paracellular spaces at the cell-cell interface. Such paracellular ice penetration occurred in the majority of cell pairs observed, and typically preceded and colocalized with the IIF initiation events. Paracellular ice penetration was generally not observed at temperatures >â5.65°C, which is consistent with a penetration mechanism via defects in tight-junction barriers at the cell-cell interface. Although the maximum temperature of paracellular penetration was similar for all four cell strains, genetically modified cells exhibited a significantly higher frequency of ice penetration and a higher mean IIF temperature than did wild-type cells. A four-state Markov chain model was used to quantify the rate constants of the paracellular ice penetration process, the penetration-associated IIF initiation process, and the intercellular ice propagation process. In the initial stages of freezing (>â15°C), junction protein expression appeared to only have a modest effect on the kinetics of propagative IIF, and even cell strains lacking the gap junction protein connexin-36 exhibited nonnegligible ice propagation rates
Metagenomic Data Utilization and Analysis (MEDUSA) and Construction of a Global Gut Microbial Gene Catalogue
Metagenomic sequencing has contributed important new knowledge about the microbes that live in a symbiotic relationship with humans. With modern sequencing technology it is possible to generate large numbers of sequencing reads from a metagenome but analysis of the data is challenging. Here we present the bioinformatics pipeline MEDUSA that facilitates analysis of metagenomic reads at the gene and taxonomic level. We also constructed a global human gut microbial gene catalogue by combining data from 4 studies spanning 3 continents. Using MEDUSA we mapped 782 gut metagenomes to the global gene catalogue and a catalogue of sequenced microbial species. Hereby we find that all studies share about half a million genes and that on average 300 000 genes are shared by half the studied subjects. The gene richness is higher in the European studies compared to Chinese and American and this is also reflected in the species richness. Even though it is possible to identify common species and a core set of genes, we find that there are large variations in abundance of species and genes
A Closer Look at Bacteroides: Phylogenetic Relationship and Genomic Implications of a Life in the Human Gut
The human gut is extremely densely inhabited by bacteria mainly from two phyla, Bacteroidetes and Firmicutes, and there is a great interest in analyzing whole-genome sequences for these species because of their relation to human health and disease. Here, we do whole-genome comparison of 105 Bacteroidetes/Chlorobi genomes to elucidate their phylogenetic relationship and to gain insight into what is separating the gut living Bacteroides and Parabacteroides genera from other Bacteroidetes/Chlorobi species. A comprehensive analysis shows that Bacteroides species have a higher number of extracytoplasmic function sigma factors (ECF sigma factors) and two component systems for extracellular signal transduction compared to other Bacteroidetes/Chlorobi species. A whole-genome phylogenetic analysis shows a very little difference between the Parabacteroides and Bacteroides genera. Further analysis shows that Bacteroides and Parabacteroides species share a large common core of 1,085 protein families. Genome atlases illustrate that there are few and only small unique areas on the chromosomes of four Bacteroides/Parabacteroides genomes. Functional classification to clusters of othologus groups show that Bacteroides species are enriched in carbohydrate transport and metabolism proteins. Classification of proteins in KEGG metabolic pathways gives a detailed view of the genome's metabolic capabilities that can be linked to its habitat. Bacteroides pectinophilus and Bacteroides capillosus do not cluster together with other Bacteroides species, based on analysis of 16S rRNA sequence, whole-genome protein families and functional content, 16S rRNA sequences of the two species suggest that they belong to the Firmicutes phylum. We have presented a more detailed and precise description of the phylogenetic relationships of members of the Bacteroidetes/Chlorobi phylum by whole genome comparison. Gut living Bacteroides have an enriched set of glycan, vitamin, and cofactor enzymes important for diet digestion
Hyaluronic acid levels predict risk of hepatic encephalopathy and liver-related death in HIV/viral hepatitis coinfected patients
Background: Whereas it is well established that various soluble biomarkers can predict level of liver fibrosis, their ability to predict liver-related clinical outcomes is less clearly established, in particular among HIV/viral hepatitis co-infected persons. We investigated plasma hyaluronic acidâs (HA) ability to predict risk of liver-related events (LRE; hepatic coma or liver-related death) in the EuroSIDA study.
Methods: Patients included were positive for anti-HCV and/or HBsAg with at least one available plasma sample. The earliest collected plasma sample was tested for HA (normal range 0â75 ng/mL) and levels were associated with risk of LRE. Change in HA per year of follow-up was estimated after measuring HA levels in latest sample before the LRE for those experiencing this outcome (cases) and in a random selection of one sixth of the remaining patients (controls).
Results: During a median of 8.2 years of follow-up, 84/1252 (6.7%) patients developed a LRE. Baseline median (IQR) HA in those without and with a LRE was 31.8 (17.2â62.6) and 221.6 ng/mL (74.9â611.3), respectively (p<0.0001). After adjustment, HA levels predicted risk of contracting a LRE; incidence rate ratios for HA levels 75â250 or â„250 vs. <75 ng/mL were 5.22 (95% CI 2.86â9.26, p<0.0007) and 28.22 (95% CI 14.95â46.00, p<0.0001), respectively. Median HA levels increased substantially prior to developing a LRE (107.6 ng/mL, IQR 0.8 to 251.1), but remained stable for controls (1.0 ng/mL, IQR â5.1 to 8.2), (p<0.0001 comparing cases and controls), and greater increases predicted risk of a LRE in adjusted models (p<0.001).
Conclusions: An elevated level of plasma HA, particularly if the level further increases over time, substantially increases the risk of contracting LRE over the next five years. HA is an inexpensive, standardized and non-invasive supplement to other methods aimed at identifying HIV/viral hepatitis co-infected patients at risk of hepatic complications
Effects of deposition temperature on the mechanical and structural properties of amorphous Al-Si-O thin films prepared by RF magnetron sputtering
Aluminosilicate (Al-Si-O) thin films containing up to 31 at. % Al and 23 at.
% Si were prepared by reactive RF magnetron co-sputtering. Mechanical and
structural properties were measured by indentation and specular reflectance
infrared spectroscopy at varying Si sputtering target power and substrate
temperature in the range 100 to 500 {\deg}C. It was found that an increased
substrate temperature and Al/Si ratio give denser structure and consequently
higher hardness (7.4 to 9.5 GPa) and reduced elastic modulus (85 to 93 GPa)
while at the same time lower crack resistance (2.6 to 0.9 N). The intensity of
the infrared Si-O-Si/Al asymmetric stretching vibrations shows a linear
dependence with respect to Al concentration. The Al-O-Al vibrational band (at
1050 cm-1) shifts towards higher wavenumbers with increasing Al concentration
which indicates a decrease of the bond length, evidencing denser structure and
higher residual stress, which is supported by the increased hardness. The same
Al-O-Al vibrational band (at 1050 cm-1) shifts towards lower wavenumber with
increasing substrate temperature indicating an increase in the of the average
coordination number of Al.Comment: Preprin
- âŠ