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Using data with monitored automotive brake anchors for more than one year and expert analysis of industrial manufacturing, researchers have developed a new, high yield-strength material grade of iron. The [...]

This research work demonstrates that new cast iron materials can be developed aided by an expert digital twin (manufacturing twin) and model predictive controls developed based on artificial intelligent tools. The well-known EN GJS-550 high strength standard material grade with yield strength exceeding 370 MPa, commonly used for safety components, can be replaced with the new HS420/250 grade with a yield strength higher than 420 MPa, elongation higher than 5%, with the resulting hardness maintained below 250 HB (Brinell Hardness). The new high yield strength material grade was developed by expert analysis of industrial manufacturing data with monitored automotive brake anchors for more than one year. This 13.5% increase in yield strength opens new design opportunities for lightweight cast iron components. Using the model predictive control and the corrective protocols developed, a light weight designed automotive brake anchors component was successfully manufactured with the new high yield strength material.

AbstractFunctional responses measure the trophic interactions between species, taking into account the density and behavior of the interacting species. In predator-prey interactions, the prey preference of the predator and the antipredator behavior of the prey together determine the feeding rate of the predator and the survival rate of the prey. Consequently, the behavior dependent functional responses make it possible to establish dynamic ecological models providing insight, among others, into the coexistence of predator and prey species and the efficiency of agents in biological pest control. In this paper the derivation methods of functional responses are reviewed. Basically, there are three classes of such methods: heuristic, stochastic and deterministic ones. All of them can take account of the behavior of the predator and prey. There are three main stochastic methods for the derivation of functional responses: renewal theory, Markov chain and the Wald equality-based method. All these methods assume that during the foraging process the prey densities do not change, which provides a mathematical basis for heuristic derivation. There are two deterministic methods using differential equations. The first one also assumes that during the foraging process the prey densities do not change, while the second one does not use that assumption. These derivation methods are appropriate to handle the behavior dependent functional responses, which is essential in the derivation of ecological games, when the payoff of prey and predator depends on the strategies of the prey and predator at the same time.

Population dynamics models suggest that the over-all level of resource productivity plays an important role in community dynamics. One such factor of resource productivity is the quality of the host plant, which can determine the effectiveness of entomophagous (predatory and parasitoid) species by altering the growth rate of the phytophagous population via effects on fecundity, survival, and rate of development. These effects have been studied in relation to the distribution of host plants and their physiological state. However, few studies have considered the differences among plant cultivars. The objective of this study was to identify a continuous-time dynamic model, to describe the effects of different tomato cultivars on a one predatortwo prey model. The experiment was carried out under greenhouse conditions using ten tomato cultivars, with the predatory species Nesidiocoris tenuis(Reuter) (Insecta, Hemiptera, Miridae) and two prey species: the phytophagous species Bemisia tabaci(Gennadius) (Insecta, Hemiptera, Aleyrodidae) and the parasitoid species Trichogramma achaeae(Nagaraja & Nagarkatti) (Insecta, Hymenoptera, Trichogrammatidae); the latter was used as the intraguild-prey. Using the software SIMFIT, we found that a three-dimensional Lotka-Volterra type system could be well fitted to the data, estimating the phytophagous species´ growth rate, the parasitoid and predator mortality rates, the predation and parasitism rates, and the parasitoid emergence rate according to the cultivar type. The results showed an important effect of the host plant quality, by cultivar, on intraguild predation, resulting in important changes in the dynamics of phytophagous populations. These results are also discussed in relation to their importance in the biological control of pest species in greenhouse crops.

Cannibalism is a common phenomenon among insects. It has raised considerable interest both from a theoretical perspective and because of its importance in population dynamics in natural ecosystems. It could also play an important role from an applied perspective, especially when using predatory species in biological control programmes. The present paper aims to study the cannibalistic behaviour of Nabis pseudoferusRemane and the functional response of adult females. In a non-choice experiment, adult females showed clear acceptance of immature conspecifics as prey, with relatively high mortality values (51.89 ± 2.69%). These values were lower than those occurring for heterospecific prey, Spodoptera exiguaHübner, under the same conditions (80.00 ± 2.82%). However, the main result was that the rate of predation on heterospecific prey was reduced to 59.09 ± 7.08% in the presence of conspecific prey. The prey-capture behaviour of adult females differed when they hunted conspecific versus heterospecific prey. This was shown in the average handling time, which was 23.3 ± 3.3 min in the first case (conspecific) versus 16.6 ± 2.5 min in the second (heterospecific). Furthermore, the values increased in the former case and declined in the latter according to the order in which the prey were captured. The difference in handling time was not significant when adjusting the adult female functional response to conspecific nymphs. We argue that these results likely indicate risk aversion and a fear of reprisal among conspecifics.

Insect parasitoids have been widely studied, particularly due to their ecological implications through the study of the special relationships observed among this kind of species, as well as to their expression in mathematical models. However, there are still scarce studies on parasitoid relationships and their expression in more realistic mathematical models. The present work is aimed at deepening into competition relationships among parasitoids. Bearing this purpose in mind, the system shaped by two parasitoids was chosen: Trichogramma brassicae(idiobiont egg parasitoid) and Chelonus oculator(koinobiont egg-larval parasitoid). Both species compete against each other for the same host species (Lepidoptera). The results obtained in the laboratory point out that T. brassicaemay be considered a better competitor than Ch. oculator. This is the result of the extrinsic competition due to the substances injected by the female during parasitization. However, our results show this classification into better and worse competitors inaccurate. Thus, these interspecific competition influences are detrimental to both parasitoid species. This is the first time that the effect of this competition is mentioned regarding parasitoid functional response. Our results and their ecological implications are reported and discussed.

When an opportunistic predator is looking for a given type of prey and encounters another one from different species, it tries to utilize this random opportunity. We characterize the optimal levels of this opportunism in the framework of stochastic models for the two prey-one predator case. We consider the spatial dispersal of preys and the optimal diet choice of predator as well. We show that when both preys have no handling time, the total opportunism provides maximal gain of energy for the predator. When handling times differ with prey, we find a conditional optimal behavior: for small density of both prey species the predator prefers the more valuable one and is entirely opportunistic. However, when the density of the more valuable prey is higher than that of the other species, then the predator prefers the first one and intentionally neglects the other. Furthermore, when the density of the less valuable prey is high and that of the other one is small, then predator will look for the less valuable prey and is therefore totally opportunistic. We demonstrate that prey preference is remunerative whenever the advantage of a proper prey preference is larger than the average cost of missed prey preference. We also propose a dynamics which explicitly contains two sides of shared predation: apparent mutualism and apparent competition, and we give conditions when the rare prey goes extinct.

The paper deals with two bee species collecting nectar from two plant species. It is assumed that the nectar stock is reduced but not exhausted by the nectar collection, each individual's pay-off depends linearly on its own foraging strategy (i.e., on the probability of a visit to a plant species) and on the average strategies of both species. For the corresponding matrix game model, it is shown that evolutionary stability of a totally mixed equilibrium foraging strategy pair is only determined by the efficiency parameters of nectar collection. The latter parameters depend on morphological characteristics of all involved species, determined by the long-term evolutionary processes. The evolutionarily stable foraging strategy is locally asymptotically stable with respect to the corresponding replicator dynamics.

One hundred and fifteen cases of pulmonary tuberculosis (PTB) in children under 10 were reviewed, including a case—control retrospective study between HIV positive (+ ve) and HIV negative (–ve) children. Overall, respiratory symptoms not responding to acute respiratory infection (ARI) protocol and >10% weight loss or failure to thrive during 3 months were the main presenting symptons, but chronic fever alone is also common in HIV infected children with PTB. Hylar enlargement is the most frequent radiologic pattern, although lobar infiltrates are common when HIV infection coexists. Gastric lavage culture was an important diagnostic tool but Mantoux test, gastric lavage direct smear and erythrocyte sedimentation rate (ESR) levels, were not helpful in diagnosing PTB. Our findings suggest that when HIV infection is suspected or confirmed, chronic fever and lower lobe infiltrates should also be considered as PTB warning signs.

Reflux esophagitis is believed to be related to acid exposure, and it is tempting to assume that the extent of mucosal damage should correlate with pH-metering values. In order to test this hypothesis we studied 151 children with gastroesophageal reflux (GER) documented by X-ray manometry, and pH studies fiberendoscopically. Biopsies taken from each child were assigned to one of four grades according to degree of leukolyte infiltration, basal layer thickening, and papillary lengthening. Histologic esophagitis was demonstrated in 59% of cases, but was severe in only 4%. The histologic grade was independent of endoscopic evaluation, which, in addition, upgraded the lesions (73% esophagitis with 19.2% severe grades). It was also independent of the eventual need for surgery. On the other hand, esophagitis grade significantly correlated with percentage of time at pH below 4 (Spearman's r = 0.18, P < 0.05) and number of GER episodes (Spearman's r = 0.28, P < 0.01). Fiberendoscopic-histologic assessment of esophagitis has been useful in our hands as a complement to other diagnostic GER studies, but its value as an isolated procedure is questionable: it is probably very reliable in the relatively rare severe cases, but the clinical picture is so revealing in these cases as to make it unnecessary. In mild and moderate grades, which are much more frequent in children, it was not a suitable method for evaluating the severity of GER and did not assist in the establishment of surgical indications.

Rural hospitals in Africa face the challenge of an increasing number of pulmonary tuberculosis (PTB) cases, much of it related with the AIDS pandemic. The main diagnostic tool in these hospitals is the direct sputum smears. Sensitivity of direct sputum smears is low, especially in cases of AIDS related PTB. Several concentration methods have been described but none is routinely used in Zimbabwe. Fluorescence microscopy of auramine stained samples increases sensitivity and saves laboratory time but it is not an appropriate technique for rural African hospitals. In a rural hospital of southwest Zimbabwe, we studied the sensitivity and appropriateness of a simplified concentration method. The sensitivity against culture was significantly higher with the concentration method (80%) than with the classical direct smear method (57%). However, when sputum is not adequate (with high number of squamous epithelial cells, meaning upper airway origin), the sensitivity of this method is low. A combination of both methods is proposed to increase the sensitivity of PTB diagnosis in rural hospitals.

This study analyzes the insights and sentiments of the anti-vaccine movements in the social media. The data, comprising of tweets and excerpts, are pre-processed to omit noise and irrelevant data. They are clustered using the k-means clustering algorithm. Each word belonging to a cluster is processed by VADER sentiment analyzer. Prevalent sentiments per cluster label the mood associated in the cluster. The results suggest insights about vaccines such as: side effects, post-shot injuries, ineffectiveness, damage from ingredients, unvaccinated elite, reinforcement of the right to not vaccinate, toxic ingredients, big pharmaceuticals' profit maximization, links to autism, and health issues after getting vaccine shots. To evaluate k-means results, the silhouette score is determined to indicate how far a point is to other nearby clusters. The resulting average silhouette score of all points is 0.013540022 which indicates that the points are close to the decision boundaries.

Mathematical systems theory and optimal control have been mostly developed in the context of engineering. In this paper it is shown how these techniques can be applied in population genetics. Based on the classical Fisher's selection model, first a very natural monitoring problem is studied: can the change of the genetic state of a population (described in terms of allele frequencies) be uniquely recovered from the observation of the frequencies of certain phenotypes? We give sufficient conditions for a positive answer to this question in a typical case of heterosis (when mixed genotypes are better than the pure ones, implying stable coexistence of all allele types). The second question is: How to effectively estimate the genetic composition of the population from phenotypic observation? The answer is observer design, which is carried out for two different dominance structures, determining the manifestation of the genetic state. In a model of artificial selection, we show how the population can be steered into equilibrium where maximal mean fitness is attained. Finally, the application of the above methodology is also extended to selection–mutation models, where both fitness parameters and mutation rates are controlled. [ABSTRACT FROM AUTHOR]