Drosophila Corazonin Neurons as a Hub for Regulating Growth, Stress Responses, Ethanol-Related Behaviors, Copulation Persistence and Sexually Dimorphic Reward Pathways

The neuronal mechanisms by which complex behaviors are coordinated and timed often involve neuropeptidergic regulation of stress and reward pathways. Recent studies of the neuropeptide Corazonin (Crz), a homolog of the mammalian Gonadotrophin Releasing Hormone (GnRH), have suggested its crucial role in the regulation of growth, internal states and behavioral decision making. We focus this review on Crz neurons with the goal to (1) highlight the diverse roles of Crz neuron function, including mechanisms that may be independent of the Crz peptide, (2) emphasize current gaps in knowledge about Crz neuron functions, and (3) propose exciting ideas of novel research directions involving the use of Crz neurons. We describe the different developmental fates of distinct subsets of Crz neurons, including recent findings elucidating the molecular regulation of apoptosis. Crz regulates systemic growth, food intake, stress responses and homeostasis by interacting with the short Neuropeptide F (sNPF) and the steroid hormone ecdysone. Additionally, activation of Crz neurons is shown to be pleasurable by interacting with the Neuropeptide F (NPF) and regulates reward processes such as ejaculation and ethanol-related behaviors in a sexually dimorphic manner. Crz neurons are proposed to be a motivational switch regulating copulation duration using a CaMKII-dependent mechanism described as the first neuronal interval timer lasting longer than a few seconds. Lastly, we propose ideas to use Crz neuron-induced ejaculation to study the effects of fictive mating and sex addiction in flies, as well as to elucidate dimorphic molecular mechanisms underlying reward behaviors and feeding disorders.

Environmental conditions alter behavioural organization and rhythmicity of a large Arctic ruminant across the annual cycle

The existence and persistence of rhythmicity in animal activity during phases of environmental change is of interest in ecology, evolution and chronobiology. A wide diversity of biological rhythms in response to exogenous conditions and internal stimuli have been uncovered, especially for polar vertebrates. However, empirical data supporting circadian organization in behaviour of large ruminating herbivores remains inconclusive. Using year-round tracking data of the largest Arctic ruminant, the muskox ( Ovibos moschatus ), we modelled rhythmicity as a function of behaviour and environmental conditions. Behavioural states were classified based on patterns in hourly movements, and incorporated within a periodicity analyses framework. Although circadian rhythmicity in muskox behaviour was detected throughout the year, ultradian rhythmicity was most prevalent, especially when muskoxen were foraging and resting in mid-winter (continuous darkness). However, when combining circadian and ultradian rhythmicity together, the probability of behavioural rhythmicity declined with increasing photoperiod until largely disrupted in mid-summer (continuous light). Individuals that remained behaviourally rhythmic during mid-summer foraged in areas with lower plant productivity (NDVI) than individuals with arrhythmic behaviour. Based on our study, we conclude that muskoxen may use an interval timer to schedule their behavioural cycles when forage resources are low, but that the importance and duration of this timer are reduced once environmental conditions allow energetic reserves to be replenished ad libitum. We argue that alimentary function and metabolic requirements are critical determinants of biological rhythmicity in muskoxen, which probably applies to ruminating herbivores in general.

The Analyst Model Performance Multi-tier for Increase of Efficiency Virtual Machine In Moodle Application

The use of multi-tier schema has become general phenomena in moodle application on web base in nowadays. Usually is layer presentation on the first tier. On the second tier of the application layer and layer data on the third tier. This is modelling on this paper to looking application performance on web base who is using three-tier model and the impact of value amount in the server who is controlling of each on the tier for the performance. The example in the case who is used for this modelling is the application of Moodle for the college courses in XYZ University. The framework of modelling who is used is Simply which is the simulation framework activity base on the district is using phyton language programming. The simulation on simply can using to a certain interval timer or unlimited (the ideal until for the work all is serviced). The results of the simulation are showing the best obtained by using a single server on each of layer by optimizing the speed of process on the server.

Impact of MRAI Timer on BGP Updates and Convergence Time

<p>BGP is a vital routing protocol for the communication amongst autonomous systems in the internet and has been broadly applied in all categories of large scale network. The inter-domain routing protocol (BGP) shows slow convergence, which effects on many internet applications due to its high convergence delay. The network operators broadly use different MRAI timers in BGP routers to deal with the issue of growing convergence time of the network. The variation in MRAI timer and its impact on network convergence and update messages has been broadly studied over the years. The increasing size of autonomous systems leads to rise in number of MRAI timers. Hence, the optimum use of MRAI timers can decrease the problem of slow convergence and necessity of huge number of MRAI timers. The proposed system uses the ckle minimum route advertisement interval timer (FMRAI) for fast update of routing table, which leads to reduce the convergence time of a network. In comparison with static MRAI timer of 30s the FMRAI timer leads to better result in terms of convergence time and number of update messages.</p>