mean relative growth rate
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2021 ◽  
Vol 11 (2) ◽  
pp. 101-106
Author(s):  
Lassaad Mdellel ◽  
Ahmed Abdelli ◽  
Khaled Omar ◽  
Waleed El-Bassam ◽  
Mazen Al-Khateeb

This study aimed to determine the percentage infestation and population parameters of the green peach aphid Myzus persicae under laboratory conditions and evaluate the effect of aqueous extracts of three different plants (pot marigold: Calendula officinalis, mint: Mentha viridis and rosemary: Salvia rosmarinus) on the mortality of this aphid. Extracts of these plants were used at three concentrations (C1 = 15%, C2 = 30% and C2 = 45%). Results indicate a percentage infestation of 76.9 ± 9.4%, a mean relative growth rate of 0.062 ± 0.007 and generation time of 11.12 ± 1.42 days. All treatments reduced the numbers of aphids and statistically significantly reduced the number (α < 0.01) recorded after treatment with C1, C2 and C3 of each extract. C. officinalis extract was more effective than those of M. viridis and S. rosmarinus. The highest mortality (69.82 ± 5.23%) and efficacy (61.71 ± 4.46%) were recorded for the C3 of aqueous extract of C. officinalis, whereas the lowest mortality (38.24 ± 2.42%) and efficacy (32.41 ± 1.23%) were recorded for the C1 of extract of M. viridis. The data provided indicate that aqueous extracts of C. officinalis, M. viridis and S. rosmarinus have an insecticidal effect on M. persicae and can be integrated into a pest management strategy to reduce M. persicae abundance on pepper plants.


2018 ◽  
Vol 38 (04) ◽  
pp. 387-393 ◽  
Author(s):  
Abdul Manan Dogar ◽  
Mahmood Ayyaz ◽  
Naeem Abbas ◽  
Sarfraz Ali Shad ◽  
Afifa Naeem

AbstractCotton mealybug,Phenacoccus solenopsisTinsley is an important polyphagous insect pest and causes severe losses to different crops worldwide. In the current study, we investigated the effect of different host plants, such asCaesalpinia pulcherrima,Plumeria rubra, Anthurium andraeanum, Jasminum sambac, andHibiscus rosasinensis, on the biological parameters ofP. solenopsis. The survival rate from crawler to adult, female nymphal duration, development time from crawler to female adult, and female adult weight were significantly different on the different hosts. Male nymphal duration, development time from crawler to male adult, pupal weight, emergence rate of male adults, and mean relative growth rate for male were similar on all the tested host plants. Pupal duration and generation time of male and female onH. rosasinensiswere significantly shorter than on the other hosts. Adult male and femaleP. solenopsislongevity was significantly shorter onH. rosasinensiscompared to other hosts. The fecundity was lower onC. pulcherrimaandA. andraeanumand hatchability was lower onC. pulcherrimathan on the other hosts. The net reproductive rate, the intrinsic rate of natural increase, and biotic potential and mean relative growth rate for female ofP. solenopsiswere significantly different on the tested hosts. Our results point to the role of host plants in increasing the populations ofP. solenopsisand could help to design cultural management strategies.


Author(s):  
Edda Tandi Lwoga ◽  
Raphael Zozimus Sangeda ◽  
Alfred Said Sife

Objective: This scientometric analysis was carried out to map the online visibility of pharmacy research at Muhimbili University of Health and Allied Sciences (MUHAS) from 1981 to 2016.Methods: Publish or Perish software was used to collect data for 33 scientists from the School of Pharmacy at MUHAS. We retrieved data on scholars’ publications, citation counts, the number of authors per publication, average citations per paper, average citations per year, h-index, g-index, contemporary H-index (Hc index) and the HI-norm index.Results: A total of 499 publications were recorded for all scholars and the most (61; 12.2%) productive was 2013. The whole study period recorded the mean relative growth rate (RGR) and doubling time (Dt) of 1.62 and 0.46 respectively. A great majority (484; 97%) of the publications were multiple-authored with nearly one third (157; 31.5%) of these being jointly contributed by six or more authors. The maximum number of citations received in a single publication was 241. The degree of collaboration among scientists was as high as 0.97. The top ranked pharmacy researchers showed variation in various metrics.Conclusion: The study findings indicate a continuous growth of pharmacy publications at MUHAS since 1981. There is a high level of collaboration among scholars and many publications have made a great impact through citations. 


2016 ◽  
Vol 1 (2) ◽  
pp. 214 ◽  
Author(s):  
Akhmad Murjani

Tujuan dari penelitian ini adalah untuk menentukan kecepatan pertumbuhan dan kelangsungan hidup tiga jenis ikan gurami (Trichogaster trichopterus, Pall) di rawa monoton, rawa pasang surut, dan rawa tadah hujan yang dipelihara di hapa Galam.Tiga jenis ikan gurami (Trichogaster trichopterus, Pall) mampu hidup dan beradaptasi di lingkungan budidaya, dan dapat diberi makan dengan pakan buatan seperti ikan budaya. Variasi jenis ikan tidak  signifikan mempengaruhi pertumbuhan rawa dan kelangsungan hidup ikan yang dipelihara di lingkungan budidaya rawa. Tingkat pertumbuhan berat rata-rata relatif terbaik adalah perlakuan C (ikan  gurami rawa tadah hujan) sebesar 29.36%. Tingkat pertumbuhan pangjang rata-rata relatif terbaik adalah perlakuan B (Ikan gurami padang rumput rawa) sebesar 9,35%. Konversi pakan terbaik terdapat pada perlakuan C (ikan gurami dari tadah hujan) sebesar 6.80. Tingkat keangsungan hidup terbaik terdapat pada perlakuan B, C, D yaitu sebesar 75.56%.The purpose of this study was to determine the speed of growth and survival of several varieties of three spot goramy (Trichogaster trichopterus Pall) from the monotonous marshes, tidal marshes, bogs and swamps rainfed fields that are kept in hapa Galam.Three spot goramy (Trichogaster trichopterus Pall) are able to live and adapt in the cultivation environment, and can be fed with artificial feed like most culture fish. Variations in the type of fishes did not significantly affect marsh growth and survival of fish that are kept in swamp ride cultivation environment. The mean relative growth rate of weight it is best to treatment C (fish from the marsh three spot goramy rainfed) of 29.36%. Average growth rate is relatively long it is best to treatment B (three spot goramy of marsh meadow Galam) for 9.35 %. Conversion is best to feed on the C treatment (fish from the marsh three spot goramy rainfed) of 6.80. the best survival was in treatment B, C, D of 75.56%.


2015 ◽  
Vol 744-746 ◽  
pp. 1792-1796
Author(s):  
Yan Fei Tian ◽  
Xiao Yang Wei

For the reasonable grouping of the 16 vessel traffic flow observation lines along Yangtze River to compare them with each other, essential data of nearly 6 years taken with the mean relative growth rate of traffic flow over the yearly same period set as clustering index, the clustering of the 16 vessel traffic flow observation lines was realized on MATLAB in accordance with the set index based on the basic principle and processes of Agglomerative Hierarchical Clustering Method, which indicated that the observation lines can be divided into 3 classes, and particularly Jiujiang took an exclusive class obviously different from the other two. This work would provide scientific basis of grouping the observation lines in order to reflect shipping economy of the regions where the observation lines are located and to provide reference for management decisions.


2007 ◽  
Vol 55 (8) ◽  
pp. 795 ◽  
Author(s):  
Maria Terezinha Silveira Paulilo ◽  
Sonia Regina Duz ◽  
Alexandre Siminski ◽  
Marisa Santos

This study analysed the behaviour of Cecropia glazioui Sneth. and Cedrela fissilis Vell. seedlings across a 2–50% full sun light gradient. The morphological adjustments of the seedlings to the different light regimes were interpreted as means of light interception in low light and avoidance of water stress in high light conditions. Cecropia seedlings showed greater trait plasticity at the 2–15% light interval, whereas Cedrela seedlings showed a slight tendency to present greater trait plasticity at the 15–30% light interval than the 2–15% interval. The seedlings of both species did not fully acclimate to decreasing light, showing lower values for the mean relative growth rate (RGR) components, leaf area ratio (LAR) and net assimilation rate (NAR) than seedlings under constant low light, but acclimated to increasing light, showing higher values for RGR components than seedlings under constant high light. The general responses to light gradient in these two species indicate their relative tolerance and ability to grow at low and high light and provide traits used in coping with gap dynamics. The results also indicated that the two species differed in their shade tolerance.


2000 ◽  
Vol 6 (4) ◽  
Author(s):  
Z. Seress ◽  
R. G. McKinlay ◽  
B. Pénzes ◽  
K. Sezák

Over 10 years of field trials show reductions of most of the pests in Brassicas undersown by clover. The pest-reducing effects are due to the 'appropriate / inappropriate landings' hypothesis (Finch, 1996), and the 'host plant quality' hypothesis (Theunissen, 1994). To find out the mechanisms within the 'host plant quality' hypothesis in the most promising intercropping (collards undersown by clover) glasshouse experiments were conducted to see whether intercropping influences the mean relative growth rate, fecundity and time of maturity of Myzus persicae (Sulzer) (Homoptera: Aphididae) a common pest of Brassicas. The treatment modelling intercropping showed the smallest mean relative growth rate, delayed the maturity and slowed down the growth of cabbages. The treatment modelling monocropping showed the highest mean relative growth rate and the maturity was reached earlier. These results may indicate that intercropping delays the growth of settled aphid populations, giving another proof that in the case of clover undersown cabbages the 'host plant quality' hypothesis is likely to be acting. The differences between treatments where the roots of clover and cabbages were separated and allowed to grow together suggest that the effect is via the roots by competition.  


1994 ◽  
Vol 9 (4) ◽  
pp. 101-105 ◽  
Author(s):  
Timothy B. Harrington

Abstract At two sites in southwestern Oregon, stands of tanoak (Lithocarpus densiflorus) were thinned in the second year after sprouting (1983) to create relative covers of 25, 50, or 100% of that for unthinned stands. At one site, relative covers were replicated with and without suppression of understory vegetation. Height, crown width and dominant-stem diameter were measured annually on each of 135 sprout clumps of tanoak from 1983-1988. Reductions in relative cover caused a proportionate increase in mean relative growth rate (RGR) of tanoak; however, the effect of understory suppression was not consistent. Increases in RGR of individual clumps from thinning were considerably greater for crown width (73% and 43% for large and small clumps, respectively) than for height (28% and 22%). Predicted crown width of tanoak 6 yr after thinning and understory suppression was up to 46% greater than that of clumps in untreated stands. West. J. Appl. For. 9(4):101-105.


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