The Speed of Adaptation in Large Asexual Populations

In large asexual populations, beneficial mutations have to compete with each other for fixation. Here, I derive explicit analytic expressions for the rate of substitution and the mean beneficial effect of fixed mutations, under the assumptions that the population size N is large, that the mean effect of new beneficial mutations is smaller than the mean effect of new deleterious mutations, and that new beneficial mutations are exponentially distributed. As N increases, the rate of substitution approaches a constant, which is equal to the mean effect of new beneficial mutations. The mean effect of fixed mutations continues to grow logarithmically with N. The speed of adaptation, measured as the change of log fitness over time, also grows logarithmically with N for moderately large N, and it grows double-logarithmically for extremely large N. Moreover, I derive a simple formula that determines whether at given N beneficial mutations are expected to compete with each other or go to fixation independently. Finally, I verify all results with numerical simulations.Comment: 33 pages, 6 figures. Minor changes in discussion. To appear in Genetic

Effect of laser-welding parameters on the heat input and weld-bead profile

Laser butt-welding of medium carbon steel was investigated using CW 1.5 kW CO2 laser. The effect of laser power (1.2 - 1.43 kW), welding speed (30 - 70 cm/min) and focal point position (-2.5 - 0 mm) on the heat input and the weld-bead geometry (i.e. penetration (P), welded zone width (W) and heat affected zone width (WHAZ)) was investigated using Response Surface Methodology (RSM). The experimental plan was based on Box-Behnken design. Linear and quadratic polynomial equations for predicting the heat input and the weld-bead geometry were developed. The results indicate that the proposed models predict the responses adequately within the limits of welding parameters being used. It is suggested that regression equations can be used to find optimum welding conditions for the desired criteria

Effect of mycoviruses on growth, spore germination and pathogenicity of the fungus Fusarium circinatum

Producción CientíficaAim of the study: To assess the impact on two mycoviruses recently described in F. circinatum mitovirus 1, and 2-2 (FcMV1 and FcMV2-2) on i) mycelial growth, ii) spore germination and iii) relative necrosis. Material and methods: Fourteen monosporic strains of F. circinatum (one of each pair infected with mycoviruses and the other without them) of the pathogen with and without viruses were selected for the assay. The statistical analysis, were a linear mixed model of analysis of variance considering one between-subjects factor (isolate) and one within-subjects factor with four levels (1=without viruses, 2=only virus FcMV1, 3=only virus FcMV2-2 and 4=both viruses). Main results: Colony growth rates of F. circinatum isolates were significantly reduced in presence of mycoviruses (p=0.002). The spore germination was also reduced in the F. circinatum isolates containing mycovirus as compared to mycovirus-free isolates (p<0.001). No significant differences in lesion lengths caused by F. circinatum were found in relation to the presence/absence of mycovirus (p<0.61). Research highlights: Reduction of the percentage of spore germination in the isolates of F. circinatum with mycovirus infections, as compared to free isolates, provides indications of reduction of metabolic activity and plant physiology are discussed. The lack of significant differences found in the length of the lesions caused by F. circinatum with respect to the presence/absence of mycovirus, indicates that further studies with a larger number of variables are required.Ministerio de Economía, Industria y Competitividad (projects AGL2012-39912 and AGL2015- 69370-R)European Cooperation in Science and Technology (COST Action FP1406 PINESTRENGTH)Portuguese Foundation for Science and Technology (grant SFRH/BPD/122928/2016

Effect of Lupinus albus as protein supplement on yield, constituents, clotting properties and fatty acid composition in ewes' milk

The effect of feeding lupin seeds (Lupinus albus L.) as an alternative protein source in ewe diets was investigated. Two groups of 18 Sarda ewes were fed two different isonitrogenous diets: with lupin (L) seed, given after 12 h soaking, or soybean meal (SBM) as the main protein source. DMI, variations of body weight and milk production were unaffected by the treatment. Although not statistically significant, in the group fed L diet the production of milk fat and protein was higher. Clotting properties of milk were similar for the two treatments, probably due to the small differences in the milk protein contents. The fatty acid profile of milk was affected by treatment with a larger content of short (14.19 wt% versus 12.26 wt%)- and medium (49.37 wt% versus 47.76 wt%)-chain fatty acids in milk from ewes fed the L diet. CLA content was unaffected by treatment. Triglyceride content of fat from the two diets reflects the milk fatty acid composition. Indeed, milk from L diet showed a higher level of medium-chain triglycerides, which are of particular interest to consumers with concerns over health and heart disease. The inclusion of lupin seed in the diet of lactation ewes can be a means of achieving a more desirable triglyceride profile in milk fat. Milk with enhanced nutritive quality may promote wider market penetration of sheep dairy products

Effect of Oocyte Vitrification Before and After in Vitro Maturation Towards Bcl-2, Bax and Bcl-2/Bax Ratio Expression

Objectives: to compare the expression of Bcl-2, Bax and Bcl-2/Bax ratio in cumulus cell and oocyte between vitrified oocyte pre and post in vitro maturation.Materials and Methods: Maturation was operated in medium TC 100 µl for 24 hours. Vitrification begins with washing oocyte in PBS basic medium supplemented of 20% serum for 1-2 minutes, followed by equilibration medium PBS + 20% serum + 10% ethylene glycol for 10-14 minutes, then transferred to 20% serum + PBS + 0.5 M sucrose + 15% ethylene glycol + PROH 15% for 25-30 seconds. Thawing is processed by submerging the oocytes in the media: 1). PBS + 20% serum + 0.5 M sucrose, 2). PBS + 20% serum + 0.25 M sucrose, and 3). PBS + 20% serum + 0.1 M sucrose. Imunocytochemistry observed the expression of Bcl-2, bax and Bcl-2/bax ratio.Results: Bcl-2 expression on oocyte in control group differed significantly with treatment group, Bcl-2 expression on cumulus in control group differed significantly with treatment 1 group. Bax expression on oocyte in control group differed significantly with treatment group. Bax expression on cumulus in control group differed significantly with treatment group. Bcl-2/Bax expression ratio on oocyte and cumulus did not differ significantly in all groupConclusion: No difference Bcl-2/Bax expression ratio on oocyte and cumulus between vitrified oocyte pre and post in vitro maturation

Effect of the Shape of Stator Blades on the Performance Output of a Vertical Axis Marine Current Turbine

Due to the diminishing reserves of fossil fuels and increased pollution from exploitation of these fuels, the world is focusing on the renewable energy sources. Energy from tidal waves is one of the most exciting forms of renewable energy because of its consistent nature. Hence, the predictable, consistent and reliable nature of marine currents has enthused the researchers to emphasize on harnessing energy from marine currents in order to meet the renewable energy targets. Exploitation of this technology is underway and further research is required to extract this energy optimally. Operating under water and harnessing kinetic energy has restated the importance of Vertical Axis Marine Current Turbines (VAMCTs). Recent studies have shown that the shape of the blades, within a VAMCT, has an appreciably considerable effect on its performance output. The flow field in the vicinity of the VAMCT is greatly affected by the design and shape of the stator blades. This paper presents an effort carried out to analyze the effect of the shape of the stator blades of a VAMCT on its performance output. VAMCT with curved stator blades has been analyzed and the results have been compared with the existing literature for the performance output from a VAMCT having straight stator blades. It has been shown that a VAMCT with curved stator blades performances superiorly as compared to straight stator blades. Furthermore, the operational range of a VAMCT with curved stator blades increases significantly as compared to straight stator blades

Effect of pyrolysis temperature on ochratoxin A adsorption mechanisms and kinetics by cashew nut shell biochars

Biochars were produced from cashew nut shell at 400, 600 and 800°C. Production temperature significantly affected biochar properties and consequently the adsorption mechanisms of ochratoxin A. Biochars produced at higher temperatures had significantly higher specific surface areas, resulting in higher OTA adsorption ca-pacities. The isotherms and kinetics of the adsorption were used to identify the adsorption mechanisms. For the kinetics study, experiments were carried out after adjustment of the parameters influencing the system, such as pH, biochar quantity and OTA initial concentration. Experimental results were modelled according to isotherm equations representing Langmuir model and Freundlich model. Langmuir model matched best with the experi-mental data. The chemical surface reaction was fitted to a pseudo-second order equation, with very high re-gression coefficients

Effect of Addition Catalyst Sulfate Acid and Solvents (Ch3oh) Biodiesel Production Process of Seeds Nyamplung (Calophyllum Inophyllum)

Biodiesel is made by taking the oil from the seeds by pressing nyamplung then processed through two stages of esterification and transesterification of the oil with solvent ratio between 1:1, 1:2, 1:3, 1:4 and 1:6 and added catalyst H2SO4 at process of esterification and transesterification catalyst NaOH in the process. In the process of varying the acid catalyst esterification 0.4%, 0.5%, 0.6%, 0.7% and 0.8% of the seed oil nyamplung. Operating condition is maintained at a temperature of 70 ° C, process time of 60 minutes with a time separation of 3 hours. Biodiesel products that meet the Indonesian National Standard is the composition ratio nyamplung seed oil and methanol is 1:1, the catalyst is used as much as 0.5% with an analysis of the quality of the density of 0.8870 g / ml, pH 7.30, level water 0.0616%, 1.3387 refractive index, 3.7480 cSt viscosity, Flash Point 56oC, calorific value of 9001 cal / g and 48.03 Cetane number