Convergent Phenomenon Research Articles

Prosociality and reciprocity in bottlenose dolphins (Tursiops truncatus).

Some moral behaviours, often regarded as reflecting high cognitive abilities (such as empathy, cooperation, targeted helping) are known to only be present in very few species, like great apes, elephants and cetaceans. Prosocial behaviours (producing a benefit for the recipient without necessarily involving a cost for the actor) have been mostly found in primates and, more recently, in elephants. Despite dolphins' reputation for helping their conspecifics, experimental studies about their prosocial and empathic abilities are rare. We conducted Prosocial Choice Tests in six bottlenose dolphins. The subjects had to choose between three objects: choosing the prosocial object induced the simultaneous rewarding of both the subject and a recipient individual; choosing the selfish object induced a reward only for the subject; choosing the null one did not reward anyone. We found prosociality and direct reciprocity in our subjects, and our results suggested that bottlenose dolphins might be able to modulate their prosocial and reciprocal tendencies according to partner-specific information. Subjects seemed to be more prosocial towards the other sex and more reciprocal towards same-sex recipients. This reciprocity might be underpinned by the same features that rule their behaviours in the wild (cooperating with same sex conspecifics). Moreover, an audience effect was reported, as the presence of the subject's young increased subjects' likelihood of prosocial response. Our findings highlighted that prosociality could appear in taxa other than primates, suggesting a convergent evolutionary phenomenon.

Comparative analysis of energy technology gap estimation in SADC, EU, and ASEAN via the energy metafrontier

The study employs the data envelopment analysis (DEA) approach with three inputs (real capital stock, labor, and energy consumption) and one output (real gross domestic product; real GDP) to examine the energy technology gap at the country level and focuses on three regional organizations, including Southern Africa Development Community (SADC), European Union (EU), and Association of Southeast Asia Nations (ASEAN), by using the energy metafrontier during the period from 2005 to 2013. With 44 observations (8 in SADC, 28 in the EU, and 8 in ASEAN) and a total of 396 decision-making units in the study, the empirical results show that energy technology in ASEAN hit the energy metafrontier in 2012 and 2013, while energy technology in EU was inferior to that of SADC from 2005 to 2011 after being compared together under the metafrontier framework. There is also a convergent phenomenon on the degree of dispersion in the energy technology gap ratio in both ASEAN and EU after 2008 except for that in SADC. Finally, this study finds that the correlation between real GDP and CO2 emissions exhibits a multi-N-type shape for ASEAN.

An adaptive and efficient variational mode decomposition and its application for bearing fault diagnosis

Variational mode decomposition has been widely applied to machinery fault diagnosis during these years. However, it remains difficult to set proper hyperparameters for the variational mode decomposition, including number of decomposed modes, initial center frequencies, and balance parameter. Moreover, the low efficiency of the existing variational mode decomposition methods hinders their applications to practical diagnostic task. This article proposes an adaptive and efficient variational mode decomposition method after thoroughly investigating its convergence property characteristic. A convergent tendency phenomenon is discovered and is explained mathematically for the first time. Motivated by the convergent tendency phenomenon, the proposed method rapidly and adaptively determines the number and the optimal initial center frequencies of signal latent modes with the guidance of the convergent tendencies of the initial center frequencies changing from small to large. In the proposed method, the number of decomposed modes and initial center frequencies are not hyperparameters that require to be set in advance any more, but are parameters learned from the analyzed signals. The determined parameters enable efficient extraction of the main latent modes contained in the analyzed signals. Therefore, the proposed variational mode decomposition method represents a major improvement in parameter adaption and decomposition efficiency over the existing variational mode decomposition methods. In the application for bearing fault diagnosis, the faulty modes are selected adaptively and the corresponding balance parameters are further optimized efficiently. Two experimental cases validate the proposed method and its superiority over the existing variational mode decomposition methods and the classical fast spectral kurtosis in bearing fault diagnosis.

Early metazoan life: divergence, environment and ecology.

Recent molecular clock studies date the origin of Metazoa to 750-800 million years ago (Ma), roughly coinciding with evidence from geochemical proxies that oxygen levels rose from less than 0.1% present atmospheric level (PAL) to perhaps 1-3% PAL O2. A younger origin of Metazoa would require greatly increased substitution rates across many clades and many genes; while not impossible, this is less parsimonious. Yet the first fossil evidence for metazoans (the Doushantuo embryos) about 600 Ma is followed by the Ediacaran fossils after 580 Ma, the earliest undisputed bilaterians at 555 Ma, and an increase in the size and morphologic complexity of bilaterians around 542 Ma. This temporal framework suggests a missing 150-200 Myr of early metazoan history that encompasses many apparent novelties in the early evolution of the nervous system. This span includes two major glaciations, and complex marine geochemical changes including major changes in redox and other environmental changes. One possible resolution is that animals of these still unknown Cryogenian and early Ediacaran ecosystems were relatively simple, with highly conserved developmental genes involved in cell-type specification and simple patterning. In this model, complex nervous systems are a convergent phenomenon in bilaterian clades which occurred close to the time that larger metazoans appeared in the fossil record.

Adaptive Real-Coded Genetic Algorithm for Identifying Motor Systems

In this paper, the main objective is to identify the parameters of motors, which includes a brushless direct current (BLDC) motor and an induction motor. The motor systems are dynamically formulated by the mechanical and electrical equations. The real-coded genetic algorithm (RGA) is adopted to identify all parameters of motors, and the standard genetic algorithm (SRGA) and various adaptive genetic algorithm (ARGAs) are compared in the rotational angular speeds and fitness values, which are the inverse of square differences of angular speeds. From numerical simulations and experimental results, it is found that the SRGA and ARGA are feasible, the ARGA can effectively solve the problems with slow convergent speed and premature phenomenon, and is more accurate in identifying system’s parameters than the SRGA. From the comparisons of the ARGAs in identifying parameters of motors, the best ARGA method is obtained and could be applied to any other mechatronic systems.

A matter of timing: identifying significant multi-dose radiotherapy improvements by numerical simulation and genetic algorithm search.

Multi-dose radiotherapy protocols (fraction dose and timing) currently used in the clinic are the product of human selection based on habit, received wisdom, physician experience and intra-day patient timetabling. However, due to combinatorial considerations, the potential treatment protocol space for a given total dose or treatment length is enormous, even for relatively coarse search; well beyond the capacity of traditional in-vitro methods. In constrast, high fidelity numerical simulation of tumor development is well suited to the challenge. Building on our previous single-dose numerical simulation model of EMT6/Ro spheroids, a multi-dose irradiation response module is added and calibrated to the effective dose arising from 18 independent multi-dose treatment programs available in the experimental literature. With the developed model a constrained, non-linear, search for better performing cadidate protocols is conducted within the vicinity of two benchmarks by genetic algorithm (GA) techniques. After evaluating less than 0.01% of the potential benchmark protocol space, candidate protocols were identified by the GA which conferred an average of 9.4% (max benefit 16.5%) and 7.1% (13.3%) improvement (reduction) on tumour cell count compared to the two benchmarks, respectively. Noticing that a convergent phenomenon of the top performing protocols was their temporal synchronicity, a further series of numerical experiments was conducted with periodic time-gap protocols (10 h to 23 h), leading to the discovery that the performance of the GA search candidates could be replicated by 17–18 h periodic candidates. Further dynamic irradiation-response cell-phase analysis revealed that such periodicity cohered with latent EMT6/Ro cell-phase temporal patterning. Taken together, this study provides powerful evidence towards the hypothesis that even simple inter-fraction timing variations for a given fractional dose program may present a facile, and highly cost-effecitive means of significantly improving clinical efficacy.

Variations on a bauplan: description of a new Malagasy “mermaid skink” with flipper-like forelimbs only (Scincidae,SirenoscincusSakata & Hikida, 2003)

The “forelimbs only” bauplan, characterised by the combined presence of well-developed fingered forelimbs and the complete absence of hindlimbs, is rare among terrestrial tetrapods. It is restricted to three lineages of squamates with elongated worm-like bodies, the amphisbaenian genus Bipes Lacépède, 1788 and the scincid genera Sirenoscincus Sakata & Hikida, 2003 and Jarujinia Chan-ard, Makchai & Cota, 2011. In the present study, we describe a new species of Sirenoscincus from Marosely, Port Bergé region, northwest Madagascar, which presents a remarkable variation of this bauplan. The forelimbs of S. mobydick n. sp. differ from S. yamagishii Sakata & Hikida, 2003 — the only other known species in the genus — by the complete absence of any fingers or claws, therefore superficially resembling flippers, a combination of characters unique among terrestrial tetrapods. Sirenoscincus mobydick n. sp. is also differentiated from S. yamagishii by several apomorphic cephalic scalation characters, such as: 1) the absence of the frontonasal, likely fused with the frontal (versus presence of both scales); 2) the absence of the preocular, likely fused with the loreal (versus presence of both scales); and 3) the absence of the postsubocular, likely fused with the pretemporal (versus presence of both scales). Additionally, we provide detailed data on the appendicular skeleton of this new species of “mermaid skink” based on X-ray computed tomography that reveal several significant regressions of skeletal elements: 1) autopodial bones highly reduced in size and number; 2) highly reduced pelvic girdle and complete absence of hindlimbs, with the notable exception of two faintly distinguishable bony corpuscles probably representing rudiments of ancestral hindlimb bones; and 3) regressed sclerotic ring with five ossicles only, therefore representing the lowest value ever observed among lizards. Our study highlights the importance of the rare “forelimbs only bauplan” for investigating macroevolutionary questions dealing with complete limb loss in vertebrates, a convergent phenomenon that has repeatedly occurred 16 to 20 times within Scincidae Gray, 1825.

Convergence as a renovation/conservation tool for journalism in Galicia: strategies and uncertainties

This paper offers a theoretical reflection on the concept of convergence in the Autonomous Community of Galicia, in Spain. In this geographic area, marked by its respect for journalistic tradition (especially referring to the press) and its inertia, it is possible to distinguish two different attitudes (actually conflicting) with regard to the convergence phenomenon. Conservation strategies coexist, therefore, (focusing mainly on the business aspect of the convergent phenomenon) with renovation strategies (creation of new spaces on the web, great commitment to the possibilities offered by new technologies and social networks). We are presenting an analytical study of the coexistence of these two interpretations of convergence (marketing and technological, respectively) in the communication ecosystem of Galicia. We can recognize the beginning of a dialectic tension between the discourses of renovation and conservation which at present coexist in harmony. It is assumed that the information industry in Galicia will eventually choose the path that guarantees the survival of its media.

Optimal strategy of searching FPD weights scanning matrix using GA-PSO

This paper discusses a kind of optimal method used for searching flat panel display (FPD) scanning matrix. The method adopts bionic algorithm: genetic algorithm (GA) and particle swarm optimization (PSO) algorithm. The method using single GA is more time-consuming, and the search efficiency is low in later evolution; the PSO algorithm is easily falling into the local optimal solution and appears the premature convergent phenomenon. Hence, a hybrid approach of GAPSO is found to optimize the search for high grayscale weights scanning matrix. Finally in the acceptable time, it finds a weight scanning matrix (WSM) of 256 gray scales with Matlab, whose scanning efficiency reaches 94.73% and the linearity is very good.

Ostracods in the Palaeozoic?

The attribute traditionally used to recognise the occurrence of ostracods in the Palaeozoic stratigraphic record has in essence been the presence of a bivalved arthropod carapace of small size. Discoveries offering unparalleled insight into the soft part palaeobiology of tiny bivalved Palaeozoic arthropods, when taken together with the notion that a bivalved carapace is a convergent phenomenon within the Arthropoda, have in the last decade revolutionised our understanding of the nature and stratigraphic record of the major groups of ostracod present in the Palaeozoic. Evidence from appendages and other soft parts is crucial in determining systematic affinity. Evidence from the soft part anatomy of bradoriids and phos-phatocopids has undermined the record of ostracods in the Cambrian, but molecular and fossil evidence implies that they may be present at that time. In the absence of soft parts the case that lepetditicopids (Ordovician-Devonian) are ostracods remains uncertain. Myodocopes certainly occur in the Palaeozoic, as determined on a wealth of new palaeobiological evidence. As yet, supposed Palaeozoic podocopes are represented in practical terms only by fossil shells. The systematic affinity of palaeocopes — a major group in the Palaeozoic and hitherto recognised as a coherent taxon — remains enigmatic, and they may turn out to represent an artificial grouping.

Conspicuous and aposematic spines in the animal kingdom

Spines serve as a common physical defence mechanism in both the plant and animal kingdoms. Here we argue that as in plants, defensive animal spines are often conspicuous (shape and colour) and should be considered aposematic. Conspicuous spines may evolve as signals or serve as a cue for potential predators. Spine conspicuousness in animals has evolved independently across and within phyla occupying aquatic and terrestrial ecosystems, indicating that this convergent phenomenon is highly adaptive. Still, many spines are cryptic, suggesting that conspicuity is not simply constrained by developmental factors such as differences in the chemical composition of the integument. Aposematism does not preclude the signalling role of conspicuous spines in the sexual arena.

Convergent flow phenomenon mimics the appearance of venous thrombosis in gradient-echo images with or without the presence of a contrast agent

We have observed signal voids at the junction of the renal vein and the inferior vena cava in the Spoiled Grass images. They mimicked the magnetic resonance appearance of an intraluminal thrombus with and without the presence of a contrast agent. The patency of the vessels was unveiled by fast Spoiled Grass sequence with reduced echo time as well as by Doppler ultrasound. Phantom studies revealed patterns of counterrotating vortices at the confluence. The cause of this image artifact was subsequently deduced as the intravoxel spin phase dispersion arsing from the impinging flows of the renal vein and inferior vena cava. It is concluded that in regions where complex flow patterns reside, fast imaging sequences that reduce spin phase variations should always be conducted in addition to other routine sequences to exclude uncertainties in image interpretation.

Convergences Between Late Paleozoic and Modern Cardidoid Malacostraca

Study of the Middle Pennsylvanian, Mazon Creek, Essex fauna Crustacea (Johnson and Richardson, 1966; and Richardson and Johnson, 1971) of northeastern Illinois has prompted an examination of the entire Late Paleozoic radiation of caridoid malacostracans. Members of this radiation bear several gross anatomical similarities to Mesozoic-Cenozoic eucarid forms, yet are totally and completely distinct taxonomically from them. This convergent phenomenon affords a rare look at the evolution of a major taxonomic category extending over a period of some 300 million years. The comparison also bears on general theoretical considerations of diversity and convergence in evolutionary theory.

The Antarctic Circumpolar Current and the Antarctic Polar Front

A Sverdrup-type solution of the Circumpolar Current is constructed. It explains the southward shift of the current, but requires that the current is situated completely to the south of the maximal westerlies. The observations show, however, that winds and current almost coincide and that both, the wind belt and the current, show a shift to the south. A frictional model is used, which overcomes this discrepancy and allows the calculation of the transverse circulation of the current in full detail. The transverse circulation under different wind conditions is calculated and discussed and shows a strong dependence of the distribution and intensity of the various divergences and convergences on the wind. A new interpretation of the Antarctic Polar Front is given. It is regarded as a convergent or divergent phenomenon according to the wind conditions.