Search results for "MIM"
showing 10 items of 645 documents
The combined distribution/assignment problem in transportation network planning: a parallel approach on hypercube architecture
1995
The joint distribution/assignment problem plays a central role in urban transport network planning. In this problem, according to the mathematical model proposed by S. P. Evans, the trips are iteratively calculated and assigned to the network in such a way that the resulting traffic flows pattern satisfies the selfish equilibrium condition. Unfortunately the number of variables and constraints increase hardly with the greatness of the networks causing long computational time for the equilibrium solution. In this paper an nCUBE 2 parallel computing architecture is employed to solve the combined problem and to asses the potential of MIMD machines to handle large scale transportation network p…
Generative design and parametric / topological optimization of cellular structures bio-inspired by additive manufacturing
2022
Biomimicry is the practice of learning from nature and imitating its different functionalities. Nature proposes complex forms and objects which inspired designers and engineers to conceive and find solutions for their engineering problems. The fabrication of these complex objects is particularly assured by the different Additive Manufacturing (AM) techniques. Generally, biomimicry can be addressed at different levels, forms, textures, and behaviors, but in AM, it is presented under two main types. The first is the customization of parts (medical prosthesis, implants or custom sport equipments). And the second consists in the optimization for specific properties such as stiffness and lightne…
Tertiary hyperparathyroidism: a review
2021
Abstract: Tertiary hyperparathyroidism (HPT III) occurs when an excess of parathyroid hormone (PTH) is secreted by parathyroid glands, usually after longstanding secondary hyperparathyroidism. Some authorities reserve the term for secondary hyperparathyroidism that persists after successful renal transplantation. Long-standing chronic kidney disease (CKD) is associated with several metabolic disturbances that lead to increased secretion of PTH, including hyperphosphatemia, calcit-riol deficiency, and hypocalcaemia. Hyperphosphatemia has a direct stimulatory effect on the parathyroid gland cell resulting in nodular hyperplasia and increased PTH secretion. Prolonged hypocalcaemia also causes …
Measurement of the Charged-Pion Polarizability
2015
The COMPASS collaboration at CERN has investigated pion Compton scattering, $\pi^-\gamma\rightarrow \pi^-\gamma$, at centre-of-mass energy below 3.5 pion masses. The process is embedded in the reaction $\pi^-\mathrm{Ni}\rightarrow\pi^-\gamma\;\mathrm{Ni}$, which is initiated by 190\,GeV pions impinging on a nickel target. The exchange of quasi-real photons is selected by isolating the sharp Coulomb peak observed at smallest momentum transfers, $Q^2<0.0015$\,(GeV/$c$)$^2$. From a sample of 63\,000 events the pion electric polarisability is determined to be $\alpha_\pi\ =\ (\,2.0\ \pm\ 0.6_{\mbox{\scriptsize stat}}\ \pm\ 0.7_{\mbox{\scriptsize syst}}\,) \times 10^{-4}\,\mbox{fm}^3$ under the …
Effects of novelty and gregariousness in survival of aposematic prey
1997
We examined the reactions of captive wild great tits to novel unpalatable prey with (1) a traditional aposematic signal (black and yellow) (2) a novel signal (light pink), and (3) a control signal (brown). Prey were offered either singly or in groups to see whether novel signals with fewer possibilities for synergistic benefits are more dependent on grouping than are the traditional signals. Indeed, responses of birds toward unpalatable prey depended significantly on spatial distribution of prey (grouping versus solitary) and die type of die signal. Birds avoided more the traditional black and yellow signals than novel pink signals in both experimental set ups, but both of diese prey items …
Co-mimics have a mutualistic relationship despite unequal defences
2007
Defensive mimicry, where species have evolved to resemble others in order to evade predators, is quite common in the animal kingdom. The two extremes of the mimicry spectrum are known as 'batesian' and 'mullerian'. Batesian mimics develop signals — visual cues for instance — that are similar to those of species being mimicked, but stop short of adopting the attribute that makes it unprofitable prey to predators. Mullerian mimics both resemble the model species and share the anti-predation attribute — by being dangerous or unpalatable. These different types of mimic were identified a century ago, but the dynamics of mimicry between unequally defended prey remain unresolved. In an experiment …
Relative importance of taste and visual appearance for predator education in Müllerian mimicry
2006
Mullerian mimicry, by definition, is the visual resemblance between two or more aposematic prey species. According to classical Mullerian mimicry theory, comimics draw mutual benefits from the resemblance because predators have to learn to avoid only one colour pattern. In contrast, the relatively untested quasi-Batesian mimicry theory suggests that, because of differences in unpalatablility, the less toxic mimic acts like a parasite on the more defended prey, decreasing its fitness. We tested predation pressures on artificial mimicry complexes in which comimics varied both in visual similarity and in taste. Both signal and taste were important for the survival of comimics. Predators learne…
A tale of 2 signals: signal mimicry between aposematic species enhances predator avoidance learning
2010
Mullerian mimicry, where 2 or more unrelated aposematic species resemble one another, is predicted to reduce the per capita mortality of co-mimics by allowing them to share the cost of educating nao ¨ve predators about their unpalatability. However, the specific assumptions and predictions of Muller's theory of shared resemblance have been previously unsupported; some authors have suggested that the benefits of signal similarity are undetectable or at best very small. We demonstrate clearly and un- ambiguously that mimicry between 2 defended forms can provide substantial protection from uneducated predators in the manner proposed originally by Muller. By utilizing prey signals that were des…
Can experienced birds select for Müllerian mimicry?
2008
Field experiments have shown that avian predators in the wild can select for similarity of warning signals in aposematic prey (Müllerian mimicry) because a common signal is better protected than a signal that is novel and rare. The original theory of Müllerian mimicry assumes that the mechanism promoting mimicry is predator learning; by sharing a signal, the comimic species share the mortality that is due to sampling by inexperienced predators. Predation events have not been observed in the wild, and learning experiments with naive bird predators in a laboratory have not unambiguously shown a benefit of a uniform signal compared with different signals. As predators in the field experiments …