Design and evaluation of a user authentication model for IoT networks based on app event patterns

Cluster Computing - Access to a variety of Internet of Things networks can be achieved through end-user devices such as smartphones or tablets. However, these devices are susceptible to theft, loss...     

Food and feeding habits of the African catfish Clarias gariepinus (Burchell, 1822) (Pisces: Clariidae) in Lake Koka,Ethiopia

The food and feeding habits of Clarias gariepinus (Burchell, 1822) were studied in Lake Koka, Ethiopia, in May 2011 (dry month) and September 2011 (wet month). Three hundred and thirty eight nonempty stomach samples were analysed using frequency of occurrence and volumetric methods of analysis. Detritus, insects, macrophytes, zooplankton and fish were the dominant food categories by occurrence, and they occurred in 79.6%, 63.6%, 63.0%, 56.2% and 15.4% of the stomachs, respectively. Volumetrically, the above food items comprised 24.3%, 14.1%, 14.5%, 19.3% and 21.8% of the total volume of food categories. Phytoplankton and gastropods were of low importance, and they occurred in 28.7% and 8.6% of the stomachs, respectively. Their volumetric contributions were 3.2% and 2.8% of the total volume of food categories. During the dry month, fish, zooplankton, insects and detritus were important food categories, while during the wet month detritus, macrophytes, insects and gastropods were important. Smaller catfish diets were dominated by detritus, macrophytes and insects, whereas larger catfish shifted to fish and zooplankton. Based on the results, C. gariepinus was found to be omnivorous in its feeding habits in Lake Koka.     

Miocene diversification of an open‐habitat predatorial passerine radiation,the shrikes (Aves: Passeriformes: Laniidae)

Diversification of avifaunas associated with savannah and steppes appears to correlate with open habitats becoming available, starting in the Miocene. Few comparative analyses exist for families for which all species are predominantly adapted to these habitats. One such group is Laniidae (Passeriformes), which are small‐ to medium‐sized predatory passerines known for their distinctive behaviour of impaling prey. We used multispecies coalescent‐based and concatenation methods to provide the first complete species‐level phylogeny for this group, as well as an estimate of the timing of diversification. Our analyses indicate that Laniidae as currently delimited is not monophyletic, as the genus Eurocephalus is not closely related to the remaining species. The two species currently assigned to the monotypic genera Urolestes and Corvinella are part of the same clade as the Lanius species, and we propose that they are included in the genus Lanius, making Laniidae monogeneric. The initial diversification of the clade is inferred to have occurred very rapidly, starting about 7.2–9.1 million years ago, timing depending on calibration method, but in either case coinciding with the expansion of C4 grasses. An African origin is inferred in the biogeographic analysis. In the redefined Laniidae, cooperative breeding is inferred to be restricted to a single clade, characterized by gregarious behaviour and rallying. Migratory behaviour evolved multiple times within the family.     

Lipopolysaccharide (Endotoxin)-host defense antibacterial peptides interactions: Role in bacterial resistance and prevention of sepsis

Lipopolysaccharide (LPS) is the major molecular component of the outer membrane of Gram-negative bacteria and serves as a physical barrier providing the bacteria protection from its surroundings. LPS is also recognized by the immune system as a marker for the detection of bacterial pathogen invasion, responsible for the development of inflammatory response, and in extreme cases to endotoxic shock. Because of these functions, the interaction of LPS with LPS binding molecules attracts great attention. One example of such molecules are antimicrobial peptides (AMPs). These are large repertoire of gene-encoded peptides produced by living organisms of all types, which serve as part of the innate immunity protecting them from pathogen invasion. AMPs are known to interact with LPS with high affinities. The biophysical properties of AMPs and their mode of interaction with LPS determine their biological function, susceptibility of bacteria to them, as well as the ability of LPS to activate the immune system. This review will discuss recent studies on the molecular mechanisms underlying these interactions, their effects on the resistance of the bacteria to AMPs, as well as their potential to neutralize LPS-induced endotoxic shock.     

Symbiotic bacteria enable olive flies (Bactrocera oleae) to exploit intractable sources of nitrogen

Insects are often associated with symbiotic micro‐organisms, which allow them to utilize nutritionally marginal diets. Adult fruit flies (Diptera: Tephritidae) associate with extracellular bacteria (Enterobacteriaceae) that inhabit their digestive tract. These flies obtain nutrients by foraging for plant exudates, honeydew and bird droppings scattered on leaves and fruit – a nutritional niche which offers ample amounts of carbohydrates, but low quantities of available nitrogen. We identified the bacteria resident in the gut of the olive fly (Bactrocera oleae) – a worldwide pest of olives and examined their contribution to nitrogen metabolism in the adult insect. By suppressing bacteria in the gut and monitoring female fecundity, we demonstrate that bacteria contribute essential amino acids and metabolize urea into an available nitrogen source for the fly, thus significantly elevating egg production. In an ecological context, bacteria were found to be beneficial to females subsisting on bird droppings, but not on honeydew – two natural food sources. We suggest that a main gut bacterium (Candidatus Erwinia dacicola) forms an inseparable, essential part of this fly's nutritional ecology. The evolution of this symbiosis has allowed adult flies to utilize food substrates which are low or imbalanced in assimilable nitrogen and thereby to overcome the nitrogen limitations of their natural diet.     

IL-2 and related cytokines can promote T cell survival by activating AKT.

The regulated elimination of T cells serves to maintain normal immune function and prevents autoimmune responses. IL-2 family cytokines play an important role in controlling the survival of immature and mature T cells. These molecules activate the protein kinase, AKT/PKB. AKT has been shown to transduce an antiapoptotic signal in numerous cell types. In this study, we show that an active form of AKT can protect T cells from apoptosis following growth factor withdrawal and that IL-2 family cytokines can promote T cell survival by activating this kinase. We also provide evidence that AKT does not block death receptor-mediated killing of lymphocytes. These data suggest that AKT may serve as a common signaling element by which members of the IL-2 family of cytokines promote T cell survival.