657,075 research outputs found
Prediction of jet engine parameters for control design using genetic programming
The simulation of a jet engine behavior is widely used in many different aspects of the engine development and maintenance. Achieving high quality jet engine control systems requires the iterative use of these simulations to virtually test the performance of the engine avoiding any possible damage on the real engine. Jet engine simulations involve the use of mathematical models which are complex and may not always be available. This paper introduces an approach based on Genetic Programming (GP) to model different parameters of a small engine for control design such as the Exhaust Gas Temperature (EGT). The GP approach has no knowledge of the characteristics of the engine. Instead, the model is found by the evolution of models based on past measurements of parameters such as the pump voltage. Once the model is obtained, it is used to predict the behaviour of the jet engine one step ahead. The proposed approach is successfully applied for the simulation of a Behotec j66 jet engine and the results are presented
A rheological characterization of mashed potatoes enriched with soy protein isolate
The effect of the addition of soy protein isolate (SPI) (0, 15, 30, 45 and 60 g kg ) on viscoelastic properties, large deformation measurements and microstructure of fresh (FM) and frozen/thawed (F/TM) mashed potatoes was investigated. Rheological data showed weak gel behaviour for both FM and F/TM potatoes without and with added SPI together with a signi?cant decrease of system viscoelasticity (G and G ) with increasing SPI volume fraction, primarily attributed to the no interaction between the amylose/amylopectine matrix and the dispersed SPI particles or aggregates as revealed by scanning electron microscopy (SEM). Micrographs also showed that SPI formed white coarse aggregates. A freeze/thaw cycle produced a more signi?cant decrease in viscoelastic functions, due to superior aggregation of denatured SPI and reduced water activity. In F/TM samples, high correlations between small and large deformation measurements were found. Results may be useful for technological applications in SPI-enriched
The Aphrodisiac Effect and Toxicity of Combination Piper Retrofractum L, Centella Asiatica, and Curcuma Domestica Infusion
Introduction: Piper retrofractum L is a plant that acts as a stimulant on the body. A preliminary study showed that administration of infusion of 2.1 mg/10 g body weight had androgenic and anabolic effects in white mice. Piperine is the main alkaloid suspected to have an aphrodisiac effect. Centella asiatica and Curcuma domestica are the excipients. The objective of this research was to determine the toxicity and the aphrodisiac effect of a combination infusion of Piper retrofractum L, Centella asiatica and Curcuma domestica on Sprague-Dawley strain male rats.Methods: Parameters for aphrodisiac effect were the frequency of introduction, climbing, and coitus of male rats. The concentration of pre and post-treatment of male rat testosterone hormone was determined using rat testosterone ELISA kit. Sub-chronic toxicity was determined from SGOT, SGPT, urea, and kreatinin concentrations of pre and post treatment of rats orally administered the combination infusion everyday for 3 months.Results: There were signifi cant differences in coitus and climbing frequencies between the male rat group administered combination infusion of Piper retrofractum L., Centella asiatica, and Curcuma domestica and the group not given the infusion (P=0.032). There was no signifi cant difference between testosterone levels of the group administered the infusion and kontrol (P=0.248). Administering high dose (5000 mg/200 g BW) of infusion caused a signifi cant difference in levels of SGOT and SGPT between pre and post-treatment.Conclusion: The infusion of 1000 mg/200 g body weight had safe aphrodisiac effect on male Sprague-Dawley rats libido. (Health Science Indones 2012;1:19-22
International shocks and national house prices
The paper investigates linkages between general macroeconomic conditions and the housing market for the G-7 area. Among the key results of the paper, it is found that the US are an important source of global fluctuations not only for real activity, nominal variables and stock prices, but also for housing prices. Yet, also regional factors may be relevant to account for house prices dynamics. Secondly, albeit distinct driving forces for real activity and ?nancial factors can be pointed out, sizeable global interactions can be found. In particular, global supply-side shocks are found to be important determinant of G-7 house prices fluctuations. The linkage between housing prices and macroeconomic developments is however bidirectional, since evidence of signi?cant wealth e€ects can be found, with investment showing in general a stronger reaction than consumption and output.G7, house prices, international business cycle, factor vector autoregressive models, common factors
IMMACULATE CONCEPTION, INCUBATION PROTOCOLS, AND EGG CHARACTERISTICS OF THE GANGES SOFTSHELL TURTLE (ASPIDERETES GANGETICUS)
Reproductive biology of Aspideretes gangeticus was studied between 1986 and 2001. Clutchsize averaged 17.9 eggs and ranged between six to thirty-fi ve eggs. Egg length averaged 30.6 mm,egg width averaged 30.22 mm, and egg weight averaged 16.85 g. Clutch volume averaged 253.75ml. No signifi cant difference was observed in clutch size between dry and wet seasons. Of the variousincubation protocols tested, one that involved transitional temperatures of 28Âș â 31Âș C, to chilling at15Âș â 18Âș C, and then 23Âș â 26Âș C resulted in the highest hatching success. Aspideretes gangeticusexhibit two forms of development arrest during incubation, embryonic diapause early in incubation andembryonic aestivation in the latter trimester of incubation. The two Aspideretes gangeticus femalesthat produced clutches for the current study produced eggs with a high fertility percentage throughoutthe fi fteen years for which they stored sperm
Intrinsic Knotting of Partite Graphs
A graph is intrinsically knotted (IK) if for every embedding of the graph there exists a knotted cycle. Let G be a multipartite graph, and form the multipartite graph G by increasing the number of vertices in each of the parts except one and then deleting an edge. We show that if G is IK, then the resulting graph G is also IK. We use this idea to describe large families of IK multipartite graphs. In particular we use the fact that K5,5\2e is IK to show that a bipartite graph with 10 or more vertices (respectively 12 or more vertices) with exactly 5 (resp. 6) in one part and E(G) \u3c= 4V(G)-17 (resp. E(G) \u3c=5V(G)-27) is IK. Our method cant be improved since we also show that K5,5\3e is not IK in general
Behavioural response of workers to repeated intergroup encounters in the harvester ant Messor barbarus
This is the author accepted manuscript. The final version is available from Springer via the DOI in this record.The evolution of cooperation in animal societies is often associated with the evolution of hostility
towards members of other groups. It is usually predicted that groups under attack from outsiders
should respond by becoming more cohesive or cooperative. However, the responses of individuals
to real or simulated intergroup encounters vary widely, for reasons that are poorly understood. We
tested how groups of workers of the harvester ant, Messor barbarus, responded to exposure to
members of a different colony versus members of their own colony, and how previous exposure to
an intruder affected the intensity of the within-group response. We found that workers increased in
activity and had more contact with one another immediately following exposure to an ant from a
different colony, but also showed a similar behavioural response to presentations involving an ant
from their own colony. However, exposure to an intruder from a different colony resulted in much
stronger behavioural responses to a second intruder, encountered shortly afterwards. Our results
are consistent with studies of social vertebrates which suggest that exposure to intruders results in
increased social cohesion. Our results also show that exposure to an intruder primes group members
to respond more strongly to future intrusions. Our findings highlight a disconnect between the
assumptions of theoretical models which study the effect of intergroup conflict on social evolution
over many generations, and the short-term behavioural responses that are the usual focus of studies
of intergroup conflict in insects and vertebrates.Natural Environment Research Council (NERC
OdreÄivanje protuhelmintiÄkog uÄinka frakcija iscrpaka biljke Spigelia anthelmia na pokusnu invaziju obliÄem Nippostrongylus brasiliensis u ĆĄtakora
This study was undertaken to screen fractions of extracts of Spigelia anthelmia to fi nd out its anthelmintic activity against experimental Nippostrongylus braziliensis infection in rats. 1000 g of the ethanolic crude extract of Spigelia anthelmia yielded 199 g (19.9%) while fractionation with chloroform, water and ethylacetate yielded 120 g (60%), 64 (32%) and 9 g (4.5%) respectively. In the anthelmintic trial in rats, the aqueous and ethylacetate fractions gave a highly signifi cant (P0.05) deparasitization when compared with the control. However, comparing the fractions with each other, chloroform and ethylacetate fractions gave a non signifi cant (P>0.05) deparasitization while the aqueous fraction gave a highly signifi cant (P0,001) dok kloroformna frakcija nije imala znaÄajan uÄinak (P0,05), dok je vodena frakcija imala znaÄajan protuhelmintiÄki uÄinak (P<0,001) iz Äega proizlazi da samo vodena frakcija sadrĆŸi aktivne protuhelmintiÄke sastojke
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