Effect Of Changes In State Research Articles

An emerging intelligent optimization algorithm based on trust sensing model for wireless sensor networks

Due to the limitation of battery power, processing capacity, and storage, the sensor nodes are easy to be captured, destroyed, or attacked in an open environment. As a result, the security and reliability of data transmission cannot be guaranteed. In order to resist the internal attacks from malicious nodes, an ant colony optimization algorithm for secured routing based on trust sensing model (ACOSR) in wireless sensor networks is proposed. Firstly, a reliable evaluation model of trust perception is presented, which can estimate the node’s trust value derived from its behavior to identify or isolate the malicious nodes effectively. The penalty function and regulator function are applied to reflect the effect of state changes on the trust value according to the node’s behavior in the process of the communication. Secondly, the trust evaluation model is introduced into the ant colony routing algorithm to improve the security for data forwarding. The simulation results show that the proposed algorithm has improved the performance significantly in terms of packet loss rate, end to end delay, throughput, and energy consumption and demonstrates good resistance to black hole attack.

Metabolic State Alters Economic Decision Making under Risk in Humans

BackgroundAnimals' attitudes to risk are profoundly influenced by metabolic state (hunger and baseline energy stores). Specifically, animals often express a preference for risky (more variable) food sources when below a metabolic reference point (hungry), and safe (less variable) food sources when sated. Circulating hormones report the status of energy reserves and acute nutrient intake to widespread targets in the central nervous system that regulate feeding behaviour, including brain regions strongly implicated in risk and reward based decision-making in humans. Despite this, physiological influences per se have not been considered previously to influence economic decisions in humans. We hypothesised that baseline metabolic reserves and alterations in metabolic state would systematically modulate decision-making and financial risk-taking in humans.Methodology/Principal FindingsWe used a controlled feeding manipulation and assayed decision-making preferences across different metabolic states following a meal. To elicit risk-preference, we presented a sequence of 200 paired lotteries, subjects' task being to select their preferred option from each pair. We also measured prandial suppression of circulating acyl-ghrelin (a centrally-acting orexigenic hormone signalling acute nutrient intake), and circulating leptin levels (providing an assay of energy reserves). We show both immediate and delayed effects on risky decision-making following a meal, and that these changes correlate with an individual's baseline leptin and changes in acyl-ghrelin levels respectively.Conclusions/SignificanceWe show that human risk preferences are exquisitely sensitive to current metabolic state, in a direction consistent with ecological models of feeding behaviour but not predicted by normative economic theory. These substantive effects of state changes on economic decisions perhaps reflect shared evolutionarily conserved neurobiological mechanisms. We suggest that this sensitivity in human risk-preference to current metabolic state has significant implications for both real-world economic transactions and for aberrant decision-making in eating disorders and obesity.

Effects of State Change of Liquid Crystalline Polymer on Dynamic Visco-Elasticity of its Blends with Polyethylene-Terephthalate

Abstract The dynamic viscoelastic properties of liquid crystalline polymer (LCP) and polyethylene terephthalate (PET) blends were studied at two different temperatures: 265°C at which LCP was in solid state and 285°C at which LCP was in molten state. The PET was in molten state at both the temperatures. The storage modulus, G’, loss modulus, G’’, dynamic viscosity, h’, of blends with different compositions were evaluated and compared. The morphology of these samples was studied using scanning electron microscope, which exhibited composition dependency. A maxima was observed in the viscosity versus composition plot corresponding to 90/10 LCP/PET blend at 285°C. The G’ versus G’’ plots demonstrated the composition dependency of LCP/PET blends.

Effects of state change of liquid crystalline polymer on dynamic visco-elasticity of its blends with polyethylene-terephthalate

The dynamic viscoelastic properties of liquid crystalline polymer (LCP) and polyethylene terephthalate (PET) blends were studied at two different temperatures: 265°C at which LCP was in solid state and 285°C at which LCP was in molten state. The PET was in molten state at both the temperatures. The storage modulus, G’, loss modulus, G’’, dynamic viscosity, h’, of blends with different compositions were evaluated and compared. The morphology of these samples was studied using scanning electron microscope, which exhibited composition dependency. A maxima was observed in the viscosity versus composition plot corresponding to 90/10 LCP/PET blend at 285°C. The G’ versus G’’ plots demonstrated the composition dependency of LCP/PET blends

Brain and ventricle instability during psychotic episodes of the schizophrenias

Recent reports from serial brain scans suggest that the rate of ventricular expansion and/or brain atrophy may be accelerated in at least some schizophrenics. The authors assessed the effect of state changes upon such findings. Within-subject 3D MRIs were assessed for ventricular and brain volumes during periods of [partial] remission and of exacerbation of psychosis. Additional scans at comparable within-subject SAPS were used to assess rates of change in volumes that were independent of SAPS changes. Correlations of changes of ventricle and brain volumes vs. change of SAPS cores between scans revealed that ventricle volumes decreased during a period of psychotic exacerbation and increased at a time of [partial] remission ( r p=−0.666; P<0.0005); conversely, brain volumes increased during psychotic exacerbation and decreased at [partial] remission ( r p=+0.448; P=0.032). Scans at comparable SAPS scores suggested that the majority of patients had rates of ventricular expansion comparable to controls (0.9±0.6 cc/year), though two patients appeared to have rates of ventricular increase of 4.5±2.1 cc/year (Lilliefores P=0.036; K-means clustering F=17.75). Exacerbation of psychosis in schizophrenia is accompanied by evidence of brain swelling, especially of periventricular brain, with incroachment of brain substance upon ventricular volumes. Controlled for state changes, the majority of schizophrenics show rates of ventricular expansion or brain atrophy indistinguishable from controls.

Effects of physiological manipulations on locus coeruleus neuronal activity in freely moving cats. I. Thermoregulatory challenge

This and the following two papers examine the activity of locus coeruleus noradrenergic (LC-NE) neurons in response to a variety of physiological manipulations in unanesthetized, unrestrained cats. Unit responses were studied during a constant behavioral state in order to avoid the potentially confounding effects of state changes upon LC-NE unit discharge. In the present study, LC-NE unit activity was recorded during two thermoregulatory challenges: ambient heating and pyrogen-induced fever. These two conditions are particularly interesting since the direction of body temperature change that they produce is the same, but the thermoregulatory responses elicited are opposite, i.e. heat loss and heat gain. LC-NE neurons were activated by both manipulations. In response to ambient heating, neuronal activity increased only with the occurrence of panting, and not during earlier portions of the heating session. Following pyrogen administration, LC-NE neurons responded only during the peak increase in body temperature. Both of these effects on unit activity occurred independent of changes in behavioral state. Since both manipulations similarly increased LC-NE unit activity, despite eliciting opposite thermoregulatory responses, it appears that these neurons do not play a specific role in thermoregulation, but may participate in the response to physiological challenges in general.

Acquisition and performance effects of scopolamine and of treatment withdrawal in avoidance situations

Two experiments were carried out in order to compare the effects of scopolamine on acquisition with those of changes of state in either direction (no drug to drug and vice versa). Two avoidance tasks the acquisition of which was known to be facilitated by small doses of tertiary antimuscarinics were used. The first study on continuous discriminated lever press avoidance, with either light onset or light offset as warning signal, showed a performance enhancement after the treatment of pretrained animals, and a performance decrement in animals trained in the drug state and then shifted to placebo. The data, however, also showed a partial carry-over of the scopolamine facilitation to the no drug condition, and a partial carry-over of the no drug retardation to the drug condition. The facilitation of acquisition (reduction of shock rate, enhancement of total response rate and of discriminated responses) and all other phenomena indicated above were more marked in the light off condition, which depressed acquisition and performance in untreated animals. The second experiment on discrete-trial two-way avoidance with light onset (non directional) as CS used a 2 × 2 × 2 × 2 design, combining the features of previous studies which had shown contrasting effects of changes of state, depending on various experimental conditions. A performance decrement after treatment withdrawal was again observed in all instances. However, this experiment confirmed that the performance effects of drug administration to pretrained animals depend both on the distribution of previous practice (single 250-trial session versus 5 sessions of 50 trials each) and on the interval between the end of training and the retest (1 day versus 14 days). These results and various literature data on antimuscarinics indicate that the contrasting effects of state changes cannot be explained by simple general models. In particular, these data exclude important state dependence phenomena in the case of these agents.