Search

Playas are the primary habitats for amphibians in the Southern High Plains, USA. Spadefoot toads (Spea spp.) are the dominant amphibian species; their demographics, body size, and immunology have been altered in playas in cropland relative to native grassland landscapes. To further understand cultivation effects on spadefoots, we compared percent body lipids and fatty acid profiles of S. bombifrons and S. multiplicata among tadpoles, metamorphs, and post-metamorphic juveniles in cropland versus grassland playas. Generally, tadpoles of both species had lower percent lipids than metamorphs and juveniles. Percent lipids were influenced by cultivation only in S. multiplicata; tadpoles contained more lipids in cropland than grassland playas. Sum of all fatty acids in S. bombifrons increased after metamorphosis regardless of landscape. However, fatty acids in S. multiplicata were similar among stages in cropland whereas in the grassland habitat juveniles had increased levels compared to tadpoles and metamorphs. In both species, saturated fatty acids decreased after metamorphosis. Mono- and polyunsaturated fatty acids generally remained steady or increased after metamorphosis. However, polyunsaturated levels were lower in S. bombifrons tadpoles and S. multiplicata tadpoles and metamorphs in cropland than grassland playas. Thus, cultivation may be affecting nutritional profiles in these species with associated fitness consequences.

Spea multiplicata (New Mexico spadefoot toad) larvae were exposed to 60, 110, and 1000 microg L(-1) perchlorate dissolved in natural surface water to determine risks associated with perchlorate exposure in desert-adapted anurans. Hind- and forelimb development and tail resorption were measured to identify effects of perchlorate exposure. No perchlorate-related effects on snout-vent length, hindlimb length, and proportion metamorphosed were observed in the highest treatment group (positive control; 1000 microg L(-1)) suggesting that either S.multiplicata are not sensitive to the effects of perchlorate at the concentrations tested or that unidentified constituents of natural surface water mitigated perchlorate toxicity. To identify whether surface water mitigated perchlorate toxicity, Xenopuslaevis were exposed to 20 and 60 microg L(-1) perchlorate in surface water and synthetic laboratory prepared water (i.e., FETAX media). X.laevis exposed to perchlorate dissolved in surface water exhibited no perchlorate-related anti-metamorphic effects, whereas X.laevis exposed to perchlorate in FETAX media experienced changes in percent metamorphosing (p0.001), time to metamorphosis (p0.001), snout-vent length (p0.001), and hindlimb length (p0.001) as compared to FETAX controls. These results suggest that natural surface water can mediate perchlorate effects at concentrations up to 60 microg L(-1) for X.laevis and greater than 1 mg L(-1) for S.multiplicata, potentially due to physicochemical properties of surface water.This manuscript discusses the effects of perchlorate in natural surface water to S.multiplicata and X.laevis.

Seventeen polymorphic microsatellite loci were characterized in two Canadian species-at-risk, Great Basin spadefoot (Spea intermontana, N = 9) and the Western painted turtle (Chrysemys picta bellii, N = 8), from GTn enriched genomic libraries and cross-taxa amplification. Number of alleles per locus ranged from 2 to 9, with an average of 3.9 and 4.3 alleles/locus in Great Basin spadefoot and Western painted turtle, respectively. Mean expected heterozygosities were comparatively high (0.43–0.52), as was the power to distinguish between individuals relative to the number of loci characterized per species (multilocus PID = 9.2 × 10−5–1.6 × 10−5). These loci will be fundamental in generating historical population information in support of conservation efforts for these two imperiled species.

Anuran fossils from the middle Miocene, early Barstovian Anceney Locality in Gallatin County, Montana, are described and identified as Scaphiopus neuter Kluge, 1966. The material consists of many isolated, complete to partial bones that represent most elements of the skeleton. Scaphiopus neuter was previously known by the holotype, a partial skeleton, from the late Oligocene, early Arikareean of South Dakota and a partial ilium from the Arikareean of Nebraska, and thus the new material increases the geologic age and geographic distribution of the species. Results from a phylogenetic analysis conducted to test the relationship of Sc. neuter to other pelobatids places it in a clade containing four extant species of Spea Cope, 1866. The new combination, Spea neuter (Kluge, 1966), is proposed for the oldest and only extinct member of this genus currently known. Within Spea, Sp. neuter is the sister taxon to the clade comprised of Spea intermontana (Cope, 1863) + Spea bombifrons (Cope, 1863), a relati...

This article presents a way of determining heat transfer calibrations for multi-objective and single-objective optimization by means of genetic algorithms. The need for optimization arises from the necessity for mathematical model validation and is very relevant to practical applications. The SPEA algorithm is used for multi-objective optimization. Scalarization of the fitness function is also addressed in combination with a small population size in order to keep the computational cost of the problem to a minimum. This is because of the time spent for a fitness function evaluation which comes from numerical solution of the nonlinear partial differential equations. The result is that a value of the heat transfer coefficient is determined that produces minimal difference between experimental results and numerical predictions.

At least 25,000 playa wetlands exist in the Southern Great Plains, and most are embedded in cropland-dominated watersheds, resulting in sediment-induced alterations in hydrology and potential contamination from agricultural chemicals. These stressors have been hypothesized or shown experimentally to affect the development and function of the immune system of amphibians. We hypothesized an association between land use and immune function in playa amphibians. We compared body mass index (body mass/SVL), spleen mass index (spleen mass/SVL), and splenocyte count index (splenocyte count/SVL) in three developmental stages (tadpoles, metamorphs, juveniles) of Spea bombifrons and Spea multiplicata collected from playas embedded in either cropland or native grassland watersheds. Body mass indices of S. bombifrons and S. multiplicata tadpoles collected from grassland playas were 39% and 29% greater, respectively, than those from cropland playas. Similar responses were observed for spleen mass and cellularity in both species, as spleen mass indices and spleen cellularity indices of S. bombifrons tadpoles from grassland playas were 330% and 1,000% greater, respectively, than for tadpoles collected from cropland playas. Spleen mass and cellularity of S. multiplicata also were influenced by land use, but unlike S. bombifrons, differences were of a lower magnitude and more consistent across developmental stages. This is the first field study to link habitat alteration with altered immune system development in amphibians.

With the fast development of technologies of alternative energy, the electric power network can be composed of several renewable energy resources. The energy resources have various characteristics in terms of operational costs and reliability. In this study, the problem is the Economic Environmental Dispatching (EED) of hybrid power system including wind and solar thermal energies. Renewable energy resources depend on the data of the climate such as the wind speed for wind energy, solar radiation and the temperature for solar thermal energy. In this article it proposes a methodology to solve this problem. The resolution takes account of the fuel costs and reducing of the emissions of the polluting gases. The resolution is done by the Strength Pareto Evolutionary Algorithm (SPEA) method and the simulations have been made on an IEEE network test (30 nodes, 8 machines and 41 lines).

The immune system’s ability to adapt its B cells to new types of antigen is powered by processes known as clonal selection and affinity maturation. When the body is exposed to the same antigen, immune system usually calls for a more rapid and larger response to the antigen, where B cells have the function of negative adjustment. Based on the clonal selection theory and the dynamic process of immune response, two novel artificial immune system algorithms, secondary response clonal programming algorithm (SRCPA) and secondary response clonal multi-objective algorithm (SRCMOA), are presented for solving single and multi-objective optimization problems, respectively. Clonal selection operator (CSO) and secondary response operator (SRO) are the main operators of SRCPA and SRCMOA. Inspired by the clonal selection theory, CSO reproduces individuals and selects their improved maturated progenies after the affinity maturation process. SRO copies certain antibodies to a secondary pool, whose members do not participate in CSO, but these antibodies could be activated by some external stimulations. The update of the secondary pool pays more attention to maintain the population diversity. On the one hand, decimal-string representation makes SRCPA more suitable for solving high-dimensional function optimization problems. Special mutation and recombination methods are adopted in SRCPA to simulate the somatic mutation and receptor editing process. Compared with some existing evolutionary algorithms, such as OGA/Q, IEA, IMCPA, BGA and AEA, SRCPA is shown to be able to solve complex optimization problems, such as high-dimensional function optimizations, with better performance. On the other hand, SRCMOA combines the Pareto-strength based fitness assignment strategy, CSO and SRO to solve multi-objective optimization problems. The performance comparison between SRCMOA, NSGA-II, SPEA, and PAES based on eight well-known test problems shows that SRCMOA has better performance in converging to approximate Pareto-optimal fronts with wide distributions.

The study is the first time a mathematical algorithm known as SPEA (strength Pareto evolutionary algorithm) has been used for the optimal 'multi-objective' designing of hybrid electric energy generation systems. The algorithm provides an optimum range of solutions from which the designer can choose the most appropriate according to the relevant budgetary conditions, acceptable levels of pollutant emissions, and the amount of unprovided energy involved.

Predator-prey interactions play an important role in community dynamics and may be important for promoting genetic diversification. Diversification may be especially important when prey species have multiple anti-predator strategies available, but these strategies conflict with each other. For example, rapid sprint speed and large size are both thought to decrease vulnerability to many predators. A physiological trade-off between swimming speed and growth rate has been documented in many aquatic species and, as a result, individual genotypes may employ one strategy or the other, but not both. Although rapid sprint speed is often assumed to decrease vulnerability to predators, this has only rarely been tested. Here I provide evidence that both rapid sprint speed and large size in tadpoles of the New Mexico spadefoot toad (Spea multiplicata) decreases predation risk from carnivore morphs of its congener the Great Plains spadefoot toad (Spea bombifrons). Such conflicts, coupled with spatio-temporal variation in predation pressure, may be important in maintaining genetic variation for trade-offs.

Based on the mechanisms of immunodominance and clonal selection theory, we propose a new multiobjective optimization algorithm, immune dominance clonal multiobjective algorithm (IDCMA). IDCMA is unique in that its fitness values of current dominated individuals are assigned as the values of a custom distance measure, termed as Ab-Ab affinity, between the dominated individuals and one of the nondominated individuals found so far. According to the values of Ab-Ab affinity, all dominated individuals (antibodies) are divided into two kinds, subdominant antibodies and cryptic antibodies. Moreover, local search only applies to the subdominant antibodies, while the cryptic antibodies are redundant and have no function during local search, but they can become subdominant (active) antibodies during the subsequent evolution. Furthermore, a new immune operation, clonal proliferation is provided to enhance local search. Using the clonal proliferation operation, IDCMA reproduces individuals and selects their improved maturated progenies after local search, so single individuals can exploit their surrounding space effectively and the newcomers yield a broader exploration of the search space. The performan ce comparison of IDCMA with MISA, NSGA-II, SPEA, PAES, NSGA, VEGA, NPGA, and HLGA in solving six well-known multiobjective function optimization problems and nine multiobjective 0/1 knapsack problems shows that IDCMA has a good performance in converging to approximate Pareto-optimal fronts with a good distribution.

SUMMARY Few studies provide empirical evidence for phenotypic plasticity's role in the evolution of novel traits. One way to do so is to test whether latent plasticity is present in an ancestor that can be refined, enhanced, or diminished by selection in derived taxa (through “genetic accommodation”), thereby producing novel traits. Here, we evaluated whether gut plasticity preceded and promoted the evolution of a novel feeding strategy in spadefoot toad tadpoles. We studied Scaphiopus couchii, whose tadpoles develop an elongate gut and consume only detritus, and two derived species, Spea multiplicata and Sp. bombifrons, whose tadpoles also express a novel, short-gut phenotype in response to a novel resource (anostracan shrimp). Consistent with the expectations of plasticity-mediated trait evolution, we found that shrimp induced a range of phenotypes in Scaphiopus that were not produced with detritus. This plasticity was either suppressed or exaggerated in Spea depending on whether the induced phenotypes were adaptive. Moreover, in contrast to its effects on morphology, shrimp induced little or no functional plasticity, as assessed by gut cell proliferation, in Scaphiopus. Shrimp did, however, induce substantial proliferation in Sp. bombifrons, the species that consumes the most shrimp and that produces the short-gut phenotype the most frequently. Thus, if Spea had ancestral morphological plasticity in response to a novel diet, their shrimp-induced short-gut morphology may have undergone subsequent genetic accommodation that improved its functionality. Hence, diet-induced phenotypic plasticity may have preceded and even promoted the evolution of a novel phenotype.

It is important for any MOEA (Multi Objective Evolutionary Algorithm) to improve convergence and diversity of solutions of Pareto front, which is obtained at the termination of MOEA. There are many MOEA available in the literature: NSGA-II, SPEA, SPEA2, PESAII and IBEA. This paper aims at improving solutions diversity of Pareto front of a well known multi-objective optimization algorithm, NSGA-II. The standard NSGA-II algorithm uses crowding distance based method for maintaining solutions diversity. The limitation of crowding distance based method is that it selects two nearer solutions from the Pareto front for the mating. The SPEA algorithm uses agglomerative hierarchical average linkage based clustering method for maintaining solutions diversity. The method sometimes may not preserve extreme solutions in Pareto front. In this paper, we propose a new diversity method based on agglomerative hierarchical clustering with extreme solutions preservation. The proposed method is tested on standard test problems of MOEA. It is observed that the proposed method gives good solution diversity on two objectives test problems compared to the existing diversity method of NSGA-II.

This work proposes substantial algorithmic enhancements to the SPEA of Schlosser et al. [15] by adding cryptographic post-processing, and improved signal processing to the photonic measurement phase. Our improved approach provides three crucial benefits: (1) For some SBox/SRAM configurations the original SPEA method is unable to identify a unique key, and terminates with up to \(2^{48}\) key candidates; using our new solver we are able to find the correct key regardless of the respective SBox/SRAM configuration. (2) Our methods reduce the number of required (complex photonic) measurements by an order of magnitude, thereby shortening the duration of the attack significantly. (3) Due to the unavailability of the attack equipment of Schlosser et al. [15] we additionally developed a novel Photonic Emission Simulator which we matched against the real equipment of the original SPEA work. With this simulator we were able to verify our enhanced SPEA by a full AES recovery which uses only a small number of photonic measurements.

We describe a case history of larval Hannemania sp. (Acari: Trombiculidae) infestations in two spadefoot toads (Spea spp. Anura: Pelobatidae) captured from playa wetlands in the Southern High Plains, Texas. Hannemania sp. larvae were superficially attached to the skin, not encysted, and dermal changes were not observed. Gross field examinations revealed a presumed occurrence of Hannemania sp. in Spea spp. at four of 24 wetlands in 2003 and 2004. Although other species of amphibians were present (Ambystoma tigrinum mavortium, Bufo cognatus, Bufo debilis insidior, Pseudacris clarkii, Gastrophryne olivacea, Rana blairi, Scaphiopus couchii), investigators did not observe infestations in these species. Future research should focus on identifying this Hannemania to species level and determining if it influences Spea spp. survival.

Sodium sulfonate-terminated dendritic poly(ester-amine) (SPEA) was synthesized by sulfonation of acrylic double bond-terminated dendritic poly(ester-amine) (APEA) with sodium hydrogen sulfite (NaHSO3) in mixture of diglycol and 2-butanone under normal pressure. The structure of SPEA was characterized by IR, 1H-NMR, and elemental analysis. SPEA was water-soluble. 1.0–40.0% (mass) SPEA aqueous solutions appeared as dilatant fluid. When pH value varied from 1.5 to 12.0, the viscosity of 1–5% (mass) SPEA aqueous solutions changed very small, and the electric conductivity almost kept stable within pH 3.0–10.0. The relationship between the viscosity and the concentration of SPEA water solutions was similar to that of NaCl water solutions. The surface tension of SPEA water solutions was lower than that of polyethylene glycol 2000 water solutions with the same concentration. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Many organisms that develop in a variable environment show correlated patterns of phenotypic plasticity in several traits. Any individual trait modification can be beneficial, neutral, or deleterious in any particular environment; the organism's total fitness, which determines if the plasticity is adaptive, is the sum of these changes. Although much is known about how plastic traits contribute to fitness, less is known about the extent to which the various trait changes involved in the plastic responses share their developmental control. Shared control suggests that the various responses evolved in unison, but independent control suggests independent evolution of many components. Spadefoot toads have evolved adaptive polyphenism to cope with developing in rapidly drying ephemeral ponds. Larvae hatch as omnivores, but on exposure to an environmental cue, may develop into carnivores. We compared trait development in the two morphs and found that differences in jaw musculature, head dimensions, and intestines emerged early in development, whereas differences in shape of the tail emerged later. In omnivores, all traits except intestine length and hind-limb length were negatively allometric with body length; in carnivores, two of three jaw muscles displayed positive allometry and, among those that were negatively allometric, all except head width showed larger allometric coefficients in carnivores. Hind-limb length was positively allometric in both forms, but the allometric coefficients did not differ significantly. Intestine length was positively allometric to body length in both forms, but in this case, omnivores exhibited the higher coefficient. These results suggest that spadefoot plasticity is trait specific and the responses are suggestive of the existence of at least two modules: a suite of trophic traits that responds early in development and a suite of tail traits that responds later. The developmental control of these suites is the subject of further investigation.

This paper presents, for the first time, an application of two well-know multiobjective optimization techniques, namely, nondominated sorting genetic algorithm (NSGA) and strength Pareto evolutionary algorithm (SPEA), to the multiobjective design of power distribution systems. These algorithms have been applied to a multiobjective optimization problem with some technical constraints, minimizing the total costs while maximizing the reliability of the power distribution system. The NSGA uses a fitness sharing scheme to achieve diversity among the obtained solutions. In SPEA, it is necessary to apply a reduction procedure because of the number of solutions. For this purpose, a fuzzy c-means (FCM) clustering algorithm has been applied, with this being the first time that an FCM algorithm in the SPEA has been used. The obtained results from both techniques have been compared, concluding that both offer similar efficiency in order to solve the stated multiobjective optimization problem. The developed methodology is applicable to practical cases of design, allowing for additional requirements that the designer imposes

Body size is highly variable within and among populations, both as a result of genetic variation and as a plastic response to environmental variation. From a proximate perspective, body size depends upon cell size, cell number, and extracellular matrix, but we know little about their independent contributions to size nor how these contributions vary with environmental influences. Here, I introduce the tail muscle of anuran tadpoles as a new system for studying this issue. Body size and tail size of tadpoles is sensitive to variation in food and temperature. I show first that tail muscle size is strongly correlated with overall body size, thus making it a good tissue to study size regulation. Second, the relative role of cell size and cell number, but not extracellular matrix, shows an interaction between food and temperature treatments and across ages. For example, in young tadpoles food effects on size are due exclusively to cell size at low temperatures but both cell size and number at high temperatures. This pattern partially reverses for older tadpoles. Despite the complexity of this interaction, the two populations compared show nearly identical patterns, suggesting that the plastic response is robust.

A novel evolution algorithm with the select-best and prepotency operator (SPO), named select-best and prepotency evolution algorithm (SPEA), is proposed. The main genetic operators of SPEA are the proposed SPO and the uniform mutation operator. The SPO is defined as follows. Every individual in population has the same chance to select the best individual within its neighborhood range (the select-best range.) and produce new individuals through the crossover with the selected individual. Then the best one of two new individuals is selected as one individual of the next generation. With the SPO that preserves the diversity of individuals to avoid premature and can make excellent individuals be selected many a time, SPEA possesses advantages over conventional genetic algorithms. To compare the performances of SPEA with those of the real-coded genetic algorithm (GA), SPEA and the real-coded GA were applied to search the global optimal solution of a benchmark function. The comparison results demonstrated that SPEA spends less CPU time than the real-coded GA, the on-line, off-line, and local searching performances of SPEA are superior to those of the real-coded GA, and the probability of obtaining the global optimal solution for SPEA is larger than that for the real-coded GA. In addition, the relationship between the select-best neighborhood range and the CPU time consumed by SPEA was analyzed as well as the relationship between the select-best neighborhood range and the ratio of obtaining the global optimal solution. The results demonstrated that the proper ratio of the individual number in the select-best neighborhood to that in the population was 6%. Finally, SPEA was applied to develop a macrokinetic model of the industrial oxidation reaction of p-xylene to terephthalic acid (OXTA) in an Amoco reactor. The macrokinetic model based on the intrinsic kinetics model introduced the correction coefficients into the rate constants of the intrinsic kinetics model to indicate the mass transfer effects presented in the Amoco reactor. Then, with the data of the industrial OXTA, SPEA was employed to obtain the optimal correction coefficients, and the macrokinetic model with high precision for the industrial OXTA was developed.

The amount and time course of SpeA release from group A streptococci (GAS) was studied at different starting inoculate after exposure to different doses of penicillin, clindamycin or a combination of the 2. The release was related to the bacterial concentration and killing rate. A clinical GAS strain was exposed to benzylpenicillin, 2 and 1000 x MIC, clindamycin, 2 and 32 x MIC, or combinations of the 2. Samples for viable counts and SpeA analyses were drawn before and after the addition of antibiotics and at 3, 6 and 24 h. The SpeA release was higher at low than at high concentrations of penicillin and the combination (both, p

Group A Streptococci (GAS) from patients with pharyngitis and skin infections were examined for T serotypes, emm types, and streptococcal pyrogenic exotoxin gene types. The results were summarized as follows: 1) T and emm types were determined in 130 GAS isolates obtained between 2000 and 2004. Among 85 throat isolates, predominant T/emm types were T12/emm12 (25%), T4/emm4 (19%), and T1/emm1 (14%). Among 45 skin isolates, predominant T/emm types were T28/emm28 (13%), TB 3264/emm89 (13%), Tnontypeable/emm58 (13%), T1/emm1 (11%), and T12/emm12 (11%). Predominant T/emm types of skin isolates in 2000-2004 slightly differed from those during 1990s in our previous report. 2) The presence of streptococcal pyrogenic exotoxin genes in 292 GAS isolates obtained between 1990 and 2004 was examined. Significantly lower proportion of skin isolates, compared with throat isolates, was found to harbor the speA gene (12 versus 26%, respectively; p

Tissues from barred tiger salamanders (Ambystoma tigrinum mavortium), Great Plains toads (Bufo cognatus) and New Mexico spadefoots (Spea multiplicata) collected from 16 playa wetlands in Texas during 1999 and 2000 were examined by light microscopy. Digenean cysts were primarily distributed subcutaneously throughout the specimens and occasionally coelomic invasion was noted. The parasites within the cysts were 1.5–2 mm in diameter, with a thin (c.10 μm wide) eosinophilic-staining tegument, two suckers (oral and ventral), posteriorly located primordial genitalia and paired digestive caeca. These digeneans were identified as the metacercariae ofClinostomum attenuatum. This is the first record ofClinostomum attenuatumin these amphibian species.

Identifying the environmental mechanism(s) controlling developmental polyphenism is the first step in gaining a mechanistic and evolutionary understanding of the factors responsible for its expression and evolution. Tadpoles of the spadefoot toad Spea multiplicata can display either a "typical" omnivorous or a carnivorous phenotype. Exogenous thyroxine and feeding on conspecific tadpoles have been accepted as triggers for development of the carnivorous phenotype on the basis of a series of studies in the early 1990s. I repeated the thyroxine and conspecific-feeding assays and demonstrated that neither exogenous thyroxine nor feeding on conspecifics induces the carnivorous phenotype. Previous researchers used simple ratio statistics to argue that field-collected carnivores and thyroxine-treated tadpoles are similar, and my results supported these claims if I used the same simple ratio methodology. However, investigation of trait developmental trajectories and allometries for field-collected carnivores and thyroxine-treated and conspecific-fed tadpoles show that these phenotypes are profoundly different.

In a search for Proteus mirabilis genes that were regulated by cell-to-cell signalling, a lacZ fusion (cmr437::mini-Tn5lacZ) was identified that was repressed 10-fold by a self-produced extracellular signal from wild-type cells. However, the cmr437::mini-Tn5lacZ insertion itself led to a marked reduction in this extracellular repressing signal. The cmr437::mini-Tn5lacZ insertion was mapped to a speA homologue in P. mirabilis. Sequence analysis indicated that a speB homologue was encoded downstream of speA. Products of the SpeA and SpeB enzymes (agmatine and putrescine) were tested for repression of cmr437::lacZ. Agmatine did not have repressing activity. However, putrescine was an effective repressing molecule at concentrations down to 30 microM. A second prominent phenotype of the cmr437 (speA)::mini-Tn5lacZ insertion was a severe defect in swarming motility. This swarming defect was also observed in a strain containing a disruption of the downstream speB gene. Differentiation of the speB mutant to swarmer cells was delayed by two hours relative to wild-type cells. Furthermore, the speB mutant was unable to migrate effectively across agar surfaces and formed very closely spaced swarming rings. Exogenous putrescine restored both the normal timing of swarmer cell differentiation and the ability to migrate to speB mutants.

A globally disseminated strain of M1T1 group A Streptococcus (GAS) has been associated with severe infections in humans including necrotizing fasciitis and toxic shock syndrome. Recent clinicoepidemiologic data showed a striking inverse relationship between disease severity and the degree to which M1T1 GAS express the streptococcal cysteine protease, SpeB. Electrophoretic 2-D gel analysis of the secreted M1T1 proteome, coupled with MALDI-TOF mass spectroscopy, revealed that expression of active SpeB caused the degradation of the vast majority of secreted GAS proteins, including several known virulence factors. Injection of a SpeB+/SpeA- M1T1 GAS strain into a murine subcutanous chamber model of infection selected for a stable phase-shift to a SpeB-/SpeA+ phenotype that expressed a full repertoire of secreted proteins and possessed enhanced lymphocyte-stimulating capacity. The proteome of the SpeB-in vivo phase-shift form closely matched the proteome of an isogenic speB gene deletion mutant of the original M1T1 isolate. The absence or the inactivation of SpeB allowed proteomic identification of proteins in this M1T1 clone that are not present in the previously sequenced M1 genome including SpeA and another bacteriophage-encoded novel streptodornase allele. Further proteomic analysis of the M1T1 SpeB+ and SpeB- phase-shift forms in the presence of a cysteine protease inhibitor demonstrated differences in the expression of several proteins, including the in vivo upregulation of SpeA, which occurred independently of SpeB inactivation.

In this paper, we present an improved version of a multi-objective evolutionary algorithm known as SPEA, which has a high capability for solving problems defined in a large size space. We applied the algorithm to solve the problem of minimization of time-energy of orbital transfer, which often appears in space missions. The computational results show that the algorithm is valid and efficient.

The paper describes a novel algorithm for finding Pareto optimal solutions to multi-objective optimization problems based on the features of a biological immune system. Inter-relationships within the proposed multi-objective immune algorithm (MOIA) resemble antibody-antigen relationships in terms of specificity, germinal center, and the memory characteristics of adaptive immune responses. Gene fragment recombination and several antibody diversification schemes (including somatic recombination, somatic mutation, gene conversion, gene reversion, gene drift, and nucleotide addition) were incorporated into the MOIA in order to improve the balance between exploitation and exploration. Using five performance metrics, MOIA simulation figures were compared with data derived from a strength Pareto evolutionary algorithm (SPEA). The results indicate that the MOIA outperformed the SPEA in several areas.

The bacteriophage-associated genes speA and speC encode streptococcal pyrogenic exotoxins of group A streptococci (GAS). Human isolates of group C and G streptococci (GCS and GGS) are commensals and the closest known genetic relatives of GAS; on occasion, GCS-GGS can cause infection that is clinically similar to GAS disease. Thirty-four human isolates of GCS-GGS were tested for speA and speC. Two GGS isolates harbored speA only, whereas a third GGS had both genes. All spe alleles found in GGS were identical to known spe alleles of GAS, except for one speA allele, which was unique. The presence of shared speA and speC alleles in GAS and GGS is highly suggestive of recent interspecies transfer. Acquisition of GAS-like virulence genes by GGS may lead to enhanced pathogenicity in this usually commensal-like organism.

Condition- or context-dependent mate choice occurs when females modify their mate preferences depending on their internal or external environment. While the ecological and evolutionary factors that favor the evolution of such plasticity are emerging, relatively little is known of the mechanisms underlying such choice. Here we evaluated whether leptin, a protein hormone involved in the regulation of appetite, might affect the expression of condition-dependent mate choice decisions. To do so, we administered leptin to spadefoot toads, Spea bombifrons, which exhibit condition-dependent mate choice for males of their own species versus congeneric males of S. multiplicata. In particular, poor-condition S. bombifrons are more likely than are good-condition S. bombifrons to prefer S. multiplicata males, but only in environments where hybridization between the two species is beneficial. We found that our leptin treatment reduced appetite in S. bombifrons adults, as was expected from leptin's known effects on appetite. However, although we predicted that leptin would reduce female preferences for heterospecific males, we found the opposite. In particular, our leptin treatment generated a consistent, repeatable preference for heterospecifics in an environment where females generally prefer conspecifics regardless of condition. These results indicate that leptin has the potential to affect female mate choice, but that it might do so in non-intuitive ways.

A modified cup-burner apparatus with a vibrating-spiral micro feeder was developed for testing the extinguishing performance of superfine powder fire extinguishing agent (SPEA). The suspension velocity of SPEA particles was calculated using the suspension-grade-model (SGD). The formation mechanism of SPEA-based aerosols was investigated theoretically, and the minimum air velocity for the SPEA particles was about 0.05m/s. Experiments were conducted on both ethanol and heptane fuels burning flames using NH4H2PO4-based SPEA with air flow rate of 60 L/min. The results show that the minimum extinguishing concentrations (MEC) of NH4H2PO4-based SPEA for ethanol and heptane fuel are 79.8g/m 3 and 98.8g/m 3 , respectively. It is demonstrated that the NH4H2PO4-based SPEA is a highly efficient fire-extinguishing agent, which is an average of 2~3 times more effective than CF3Br, and an average of 5~8 times more effective than HFC-227ea.. This research is helpful for the engineering design of superfine powder fire extinguishing equipment, as well as has vital significance to the fire protection.

En este trabajo se presenta la implementación del algoritmo evolutivo multi-objetivo de frente de Pareto (SPEA) para la planeación de la expansión de sistemas de distribución, considerando como funciones objetivos los costos de la inversión y el número de huecos de voltaje esperado por año. El algoritmo se implementa aplicándolo a un sistema de distribución real teniendo en cuenta algunos parámetros fijos del sistema, tales como el número de tramos, el número de nodos y la población inicial. También se consideran otras variables que son propias de los algoritmos evolutivos como el porcentaje en poblaciones distintas que se cruzan entre sí en una generación (cruce) y la mutación. Se concluye que la implementación de SPEA para la planeación de sistemas de distribución reales es una buena y eficiente herramienta computacional cuando se requiere considerar varias funciones objetivo. This article describes the implementation of the multi-objective evolutionary algorithm Pareto front (SPEA) for the planning of distribution system expansion, taking as target functions the investment costs and the number of Sag voltages expected per year. The algorithm is implemented by applying it to real distribution system, given some fixed system parameters such as the number of network segments, number of nodes and the number of initial population. Other variables that are proper of evolutionary algorithms such as percentage of generation population that crosses another (cross) and mutation are taken into consideration. It is concluded that the implementation of SPEA for planning real distribution systems is a good and efficient computational tool when it is necessary to consider several objective functions.

RESUMEN: En este trabajo se presenta la implementación del algoritmo evolutivo multi-objetivo de frente de Pareto (SPEA) para la planeación de la expansión de sistemas de distribución, considerando como funciones objetivos los costos de la inversión y el número de huecos de voltaje esperado por año. El algoritmo se implementa aplicándolo a un sistema de distribución real teniendo en cuenta algunos parámetros fijos del sistema, tales como el número de tramos, el número de nodos y la población inicial. También se consideran otras variables que son propias de los algoritmos evolutivos como el porcentaje en poblaciones distintas que se cruzan entre sí en una generación (cruce) y la mutación. Se concluye que la implementación de SPEA para la planeación de sistemas de distribución reales es una buena y eficiente herramienta computacional cuando se requiere considerar varias funciones objetivo. ABSTRACT: This article describes the implementation of the multi-objective evolutionary algorithm Pareto front (SPEA) for the planning of distribution system expansion, taking as target functions the investment costs and the number of Sag voltages expected per year. The algorithm is implemented by applying it to real distribution system, given some fixed system parameters such as the number of network segments, number of nodes and the number of initial population. Other variables that are proper of evolutionary algorithms such as percentage of generation population that crosses another (cross) and mutation are taken into consideration. It is concluded that the implementation of SPEA for planning real distribution systems is a good and efficient computational tool when it is necessary to consider several objective functions. COL0124235

Superantigens have been implicated as pivotal mediators of severe invasive group A streptococcal (GAS) infections, by virtue of their potent immunostimulatory activity. HLA polymorphism has been suggested to influence the susceptibility to severe invasive GAS infection. Here we studied the influence of allelic and isotypic variation of HLA class II molecules on GAS superantigen-induced immune responses using cells derived from patients with bare lymphocyte syndrome, untransfected or transfected with various HLA class II alleles. Significantly higher proliferative responses were detected when streptococcal pyrogenic exotoxin (Spe) A was presented by cells expressing DQA1*0101/DQB1*0302 (DQ3.2), as compared to cells expressing DR1, DR4, or DR5 alleles (p=0.0002–0.01). In contrast to SpeA, SpeC was preferentially presented by DR4 as compared to DQB1*03 (p=0.04). In agreement with the proliferation results, a significantly higher frequency of IL-2-, TNF-α-, TNF-β-, and IFN-γ-producing cells was detected when SpeA was presented by HLA class II DQB1*03 alleles as compared to DR4 (p=0.0002–0.04). Binding experiments showed a high affinitybinding of SpeA to both class II DR4 and DQB1*0302, and there was no significant difference in SpeA binding affinity between the two alleles. The data confirm the effect of allelic polymorphism in superantigen responses and show that different superantigens are preferentially presented by distinct class II alleles.

Procedures for performing cladistic analyses can provide powerful tools for understanding the evolution of neuropeptide and polypeptide hormone coding genes. These analyses can be done on either amino acid data sets or nucleotide data sets and can utilize several different algorithms that are dependent on distinct sets of operating assumptions and constraints. In some cases, the results of these analyses can be used to gauge phylogenetic relationships between taxa. Selecting the proper cladistic analysis strategy is dependent on the taxonomic level of analysis and the rate of evolution within the orthologous genes being evaluated. For example, previous studies have shown that the amino acid sequence of proopiomelanocortin (POMC), the common precursor for the melanocortins and beta-endorphin, can be used to resolve phylogenetic relationships at the class and order level. This study tested the hypothesis that POMC sequences could be used to resolve phylogenetic relationships at the family taxonomic level. Cladistic analyses were performed on amphibian POMC sequences characterized from the marine toad, Bufo marinus (family Bufonidae; this study), the spadefoot toad, Spea multiplicatus (family Pelobatidae), the African clawed frog, Xenopus laevis (family Pipidae) and the laughing frog, Rana ridibunda (family Ranidae). In these analyses the sequence of Australian lungfish POMC was used as the outgroup. The analyses were done at the amino acid level using the maximum parsimony algorithm and at the nucleotide level using the maximum likelihood algorithm. For the anuran POMC genes, analysis at the nucleotide level using the maximum likelihood algorithm generated a cladogram with higher bootstrap values than the maximum parsimony analysis of the POMC amino acid data set. For anuran POMC sequences, analysis of nucleotide sequences using the maximum likelihood algorithm would appear to be the preferred strategy for resolving phylogenetic relationships at the family taxonomic level.

The larvae of spadefoot toads exhibit extreme developmental/endocrinological diversity. For example, New World spadefoot toads (Scaphiopus and Spea) have the shortest larval periods known among anurans, and the tadpoles of Old World spadefoot taxa (Pelobates) are among the largest known. To analyze the patterns of this diversity in an evolutionary context, we generated comparable larval growth and development data from 10 of the 11 taxa of spadefoot toads and from one taxon of parsley frog (Pelodytes), the nearest spadefoot toad relative. We found dramatic differences in growth and development among taxa, which indicated that taxon-specific physiology, rather than phenotypic plasticity, underlies larval period diversity. For all eight response variables (development rate, three growth rates, time to forelimb emergence, time to tail resorption, mass at tail resorption, and body length at tail resorption), taxa within genera were similar to each other and were different from taxa in other genera. L...

The parameters of finance requirements, resource leveling, and anticipated profit have significant influence on many aspects of project management. These parameters interact and occasionally conflict with each other. Accordingly, achievement of a balance between these three parameters is crucial to ensure the accomplishment of project objectives. A multi-objective multimode scheduling optimization algorithm is proposed to establish the optimal trade-off between these three parameters. The strength Pareto evolutionary algorithm (SPEA) was implemented to obtain the solutions comprising the Pareto-optimal trade-off. The developed SPEA was validated by reproducing identical results of a time/cost trade-off problem in the literature. The developed SPEA was used to obtain the Pareto-optimal trade-off of a network of nine multimode activities that comprised fifty solutions. The trade-off of fifty solutions allows decision makers explore the impact of finance upon the efficiency of resource utilization an...

Background Group A streptococcus (GAS) causes invasive disease, superficial disease, and can asymptomatically colonize humans. Superantigens are one virulence factor found in GAS. Previous studies found associations between the genes that encode superantigens and emm type of GAS. It is unknown if these associations are due to underlying biological factors that limit the distribution of superantigens or, alternatively, if these associations are due to the expansion of local GAS linages where these studies took place. To further address this question we screened GAS isolates collected from Salvador, Brazil for 11 known superantigen genes. Methods Seventy-seven GAS isolates were screened by PCR for superantigen genes. These superantigen genes were speA, speC, speG, speH, speI, speJ, speK, speL, speM, ssa, and smeZ. We used Fisher’s two-sided exact test to identify associations between superantigens and GAS emm type. We then compared our results to previous reports of superantigen prevalence and superantigen association with emm type. Results In our collection we found several emm type and superantigen genotype combinations that have previously been reported in isolates from Europe and Australia. We also found that speA was significantly associated with emm type 1, and that speC was significantly associated with emm type 12. Conclusions Our study reports superantigen genotypes of GAS from a region of the world that is lacking this information. We found evidence of common GAS superantigen genotypes that are spread worldwide as well as novel superantigen genotypes that, so far, are unique to Brazil.

We examined the effects of an acute stressor on regional alpha-melanocyte-stimulating hormone (αMSH) content in the New Mexican spadefoot toad, Spea multiplicata. We first used immunocytochemistry along with radioimmunoassay (RIA) to examine the distribution of pro-opiomelanocortin (POMC) neurons in the brain of Spea. Neurons immunoreactive for αMSH, β-endorphin, and corticotropin were observed in the preoptic nucleus and ventral infundibulum of the hypothalamus. Ascending immunoreactive fibers projected to the olfactory nucleus, nucleus accumbens, and striatum. Numerous immunoreactive fibers were also observed in the hypothalamus. The thalamus/hypothalamus (T/HT) contained the greatest concentrations of αMSH as determined by RIA followed by the preoptic area (PO). Levels in the telencephalon, brain stem, and optic tectum (OT) were 14–23 times lower than in the T/HT. Exposure to a brief stressor elevated αMSH levels in the PO and OT. We conclude that Spea possesses two distinct POMC neuronal cell groups, one located in the anterior preoptic area and one located in the ventral infundibulum. Ascending projections to the basal ganglia might play an indirect role in tectal regulation and the control of prey-catching behavior. Exposure to an acute stressor alters brain αMSH content in Spea, although there are regional and temporal differences in the response pattern compared to Bufo. These findings are consistent with the notion that neuronal melanocortins influence how frogs and toads gather information about their environment during stress.

In order to compare the distribution of selected virulence genes among group A streptococci recovered from invasive disease and superficial infections, 42 isolates were screened for mga, speB, speA, ssa and ska, by PCR. The isolates were predominantly of the sequence types emml, emm3 and emm6, but also included a few of the types emm22, emm28, emm75 and emm78. The phage-mediated speA seemed to be prevalent in emm types 1 and 3, and its distribution was not related to disease severity. The other genes were present in all isolates. The raga, speB and speA were further studied by sequence analysis. Although allotypic associations with invasiveness were not found, allelic specificity to the emm sequence type was observed. In addition, the mga sequences indicated two lineages, related to opacity factor production. A possible recombination between these two main divergent mga genes was observed in isolates of the types emm22 and emm75. A logical nomenclature of the alleles of mga and speB is suggested.

The evolution of male breeding aggregations is difficult to explain because males may reduce their reproductive success by associating with their closest competitors. We examined aggregative behavior by male New Mexico spadefoot toads, Spea multiplicata, which form breeding choruses in rain-filled pools. We specifically asked whether males are attracted to conspecific calls and, if so, whether they preferentially associate with those male calls that are also attractive to females. Field observations revealed that males showed significant clustering with conspecifics within breeding ponds, whereas laboratory phonotaxis experiments revealed that males preferentially associated with conspecific male calls. Moreover, when males were presented with conspecific calls that differed in call rate, smaller males associated with the stimulus preferred by females (average call rate). Thus, males appear to evaluate the attractiveness of competitors using the same trait employed by females to assess potential mates, and males adjust their positions relative to competitors depending on their size. We discuss these results in the light of several current hypotheses on the adaptive significance of male breeding aggregations.

A largely neglected aspect of foraging behavior is whether the costs and benefits of predation vary as a function of phylogenetic (i.e., genetic) similarity between predator and prey. Prey of varying phylogenetic similarities to predators might differ in value because both the risk of pathogen transmission and the nutritional quality of prey typically decline with decreasing phylogenetic similarity between predator and prey. I experimentally evaluated this hypothesis by feeding omnivorous spadefoot toad tadpoles (Spea bombifrons, Spea multiplicata, and Scaphiopus couchii) either conspecific tadpoles or an equal mass of three different species of heterospecific prey, all of which contained naturally occurring bacteria. I also examined which prey species Spea tadpoles preferred. I found that all three species of tadpoles performed best on, and preferred to eat, prey that were of intermediate phylogenetic similarity to the predators. Prey of intermediate phylogenetic similarity may provide the greatest fitness benefits to predators because such prey balance the nutritional benefits of closely related prey with the cost of parasite transmission between closely related individuals.

When high-quality conspecifics resemble heterospecifics, females may be unable to engage effectively in both species recognition (identification of conspecifics) and mate-quality recognition (identification of high-quality mates). Consequently, females that engage primarily in mate-quality recognition may risk heterospecific matings, and females that engage primarily in species recognition may risk mating with low-quality mates. I examined the evolutionary consequences of this conflict between species and mate-quality recognition in spadefoot toads, Spea multiplicata. I compared mate preferences and the fitness consequences of these preferences in spadefoot toad populations that did and did not overlap with congeners. In non-overlapping populations, S. multiplicata females preferred an extreme call character resembling that of heterospecifics, and they had more eggs fertilized. In overlapping populations, S. multiplicata females preferred those call characteristics that were closest to the norm for their population, and they did not receive the benefit of enhanced fertilization success. Thus, S. multiplicata females appear to trade off species and mate-quality recognition, such that those co-occurring with heterospecifics forgo the benefits of high-quality matings to ensure conspecific matings. These results suggest that the interaction between species and mate-quality recognition may influence mate choice decisions in important and nonintuitive ways. Key words: mate choice, mate-quality recognition, species recognition, Scaphiopus couchii, Spea bombifrons, Spea multiplicata. [Behav Ecol 11:220–227 (2000)]

Ten tetranucleotide loci were isolated from a New Mexico spadefoot toad (Spea multiplicata) microsatellite-enriched genomic library. To assess the degree of variability in these loci, we genotyped 120 S. multiplicata tadpoles collected from six playa wetlands in the Southern High Plains. Loci revealed a high degree of allelic diversity (4–20 alleles), observed heterozygosity (0.466–0.806), and expected heterozygosity (0.485–0.900). With the isolation and characterization of these microsatellite loci there now exists 19 microsatellite loci for S. multiplicata that will prove to be powerful molecular tools for ecological, evolutionary, and conservation genetic studies on New Mexico and Plains (S. bombifrons) spadefoot toads.

In group A streptococci, genetic markers for principal tissue reservoir are located within emm genes, which encode surface proteins that have a role in virulence. A worldwide collection of 160 isolates was evaluated for two traits: chromosomal emm gene markers for tissue tropism (designated patterns A-E), and bacteriophage-associated genes (speA and speC) encoding pyrogenic exotoxins. The speA and speC alleles of organisms harboring the emm marker for a pharyngeal reservoir (pattern A-C) differ from spe alleles that predominate in organisms with the emm marker for impetigo (pattern D). However, organisms that display the emm marker for both tissue sites (pattern E) are not intermediate for the distribution of either speA or speC alleles, but instead resemble pattern A-C isolates for speA and pattern D strains for speC. Statistically significant nonrandom associations between exotoxin alleles and emm patterns were observed but cannot be readily explained by niche separation alone.

A degenerate primer, specific for the opioid core sequence YGGFM, was used to clone and sequence proopiomelanocortin (POMC) cDNAs from the brain of the African lungfish, Protopterus annectens, and from the brain of the western spadefoot toad, Spea multiplicatus. In addition, the opioid-specific primer was used to clone and sequence a 3′RACE product corresponding to a portion of the open reading frame of S. multiplicatus proenkephalin. For both species, cDNA was made from a single brain and a degenerate opioid-specific primer provided a reliable probe for detecting opioid-related cDNAs. The African lungfish POMC cDNA was 1,168 nucleotides in length, and contained regions that are similar to tetrapod POMCs and fish POMCs. The African lungfish POMC encodes a tetrapod-like γ-MSH sequence that is flanked by sets of paired basic amino acid proteolytic cleavage sites. The γ-MSH region in ray-finned fish POMCs either has degenerate cleavage sites or is totally absent in some species. However, the African lungfish γ-MSH sequence does contain a deletion which has not been observed in tetrapod γ-MSH sequences. The β-endorphin region of lungfish POMC has the di-amino acid sequence tryptophan-aspartic acid in the N-terminal region and an additional glutamic acid residue in the C-terminal region of β-endorphin – features found in fish β-endorphin, but not tetrapod β-endorphins. The western spadefoot toad POMC was 1,186 nucleotides in length, and exhibited an organizational scheme typical for tetrapod POMCs. However, the toad POMC did lack a paired basic amino acid proteolytic cleavage site N-terminal to the β-MSH sequence. Thus, like rat POMC, it is doubtful that β-MSH is an end product in either the toad brain or intermediate pituitary. At the amino acid level, the toad POMC had 76% sequence identity with Xenopus laevis POMC and 68% sequence identity with Rana ribidunda POMC. The use of these POMC sequences to assess phylogenetic relationships within anuran amphibians will be discussed. With respect to the fragment of S. multiplicatus proenkephalin cDNA, two metenkephalin sequences and the metenkephalin-RF sequence were found encoded in this fragment. As seen for X. laevis and R. ridibunda proenkephalin, a leuenkephalin sequence was not detected in the C-terminal region of the S. multiplicatus proenkephalin. The absence of a leuenkephalin sequence may be a common feature of anuran amphibian proenkephalins.

High-performance actuators are required for numerous novel applications such as human-robot assistive devices. The torque-to-weight ratio and energy efficiency of current actuation technology is often too low, which limits the performance of novel robots. Therefore, we developed a Series-Parallel Elastic Actuator (SPEA) which enables variable recruitment of parallel springs and variable load cancellation. Finding suitable intermittent mechanisms for the SPEA is however still challenging. This paper reports on the innovative design of an intermittent self-closing mechanism for a MACCEPA-based SPEA that can deliver bi-directional output torque and variable stiffness, while minimizing friction levels. Experiments on a one-layer intermittent self-closing mechanism are conducted to validate the working principle and the proposed model. A demonstrator of the MACCEPA-based SPEA with intermittent self-closing mechanism is presented and the experiments validate the modeled output torque and lowered motor torque for different stiffness settings.

The network reconfiguration for service restoration (SR) in distribution systems is a combinatorial complex optimization problem since it involves multiple non-linear constraints and objectives. For large networks, no exact algorithm has found adequate SR plans in real-time. On the other hand, methods combining Multi-objective Evolutionary Algorithms (MOEAs) with the Node-depth encoding (NDE) have shown to be able to efficiently generate adequate SR plans for large distribution systems (with thousands of buses and switches). This paper presents a new method that combining NDE with three MOEAs: (i) NSGA-II; (iii) SPEA 2; and (iii) a MOEA based on subpopulation tables. The idea is to obtain a method that cannot-only obtain adequate SR plans for large scale distribution systems, but can also find plans for small or large networks with similar quality. The proposed method, called MEA2N-STR, explores the space of the objectives solutions better than the other MOEAs with NDE, approximating better the Pareto-optimal front. This statement has been demonstrated by several simulations with DSs ranging from 632 to 1,277 switches.