نتایج جستجو برای: ecological systems indefinite weight grazing and constant yield harvesting sub supersolution method

تعداد نتایج: 17299149  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سمنان 1392

in the area of vocabulary teaching and learning although much research has been done, only some of it has led to effective techniques of vocabulary teaching and many language learners still have problem learning vocabulary. the urge behind this study was to investigate three methods of teaching words. the first one was teaching words in context based on a traditional method of teaching that is,...

Journal: :Bulletin of mathematical sciences 2022

A [Formula: see text]-Laplacian elliptic problem in the presence of both strongly singular and text]-superlinear nonlinearities is considered. We employ bifurcation theory, approximation techniques sub-supersolution method to establish existence an unbounded branch positive solutions, which bounded text]-direction bifurcates from infinity at text]. As consequence result, we determine intervals ...

Journal: :Journal of dairy science 2002
R L Powell P M VanRaden

Genetic evaluations on a global scale were calculated for Holstein bulls using the May 2001 International Bull Evaluation Service (Interbull) evaluations expressed on each of 27 national scales. National scale data were weighted by the country's proportion of total daughters from all bulls (population size) to represent market share. Correlations between Interbull evaluations on national scales...

A. Mirjalili

In this investigation, the effects of enclosure, restal delayed grazing andcontinued grazing treatments on the production rate and vegetation cover were studied.Study area was SadrAbad pasture. After selecting three bands (1+1+1=3 hectare area) asthree treatments in the restricted and non restricted area, they were transected to threetransects. Then plots (1×2m2 ) were selected to measure the p...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2009
David N Koons

For several plant and animal species, Darimont et al. (1) present compelling evidence that rates of phenotypic change driven by human harvest far outpace those driven by other selective forces. From a life-history perspective, commercial and trophy harvesting also resulted in smaller size/earlier age at first reproduction, smaller adult body size (sometimes associated with shorter lifespan), an...

Journal: :International Journal of Applied Agricultural Sciences 2022

A field experiment was conducted at Lemu-bilbilo wereda, Arsi Zone, Ethiopia, from June to December 2017/18 cropping season, with the aim of evaluating optimal level fertilizers for maximal production food barley varieties on two farmer’s site. Four levels fertilizer (RNP (100 kg/ha urea + 150 DAP) (73N, 69 P2O5), 150%RNP, 200%RNP and RNPS kg/ha) (19 N 38 P2O<su...

امام, یحیی , بیژن‌زاده, احسان, مهدیه, حسین , نادری, روح‌اله ,

Recently, application of biofertilizers has been introduced as a new strategy in crop nutrition. In order to investigate the effect of application methods of biofertilizer in combination with nitrogen levels on yield and yield components of weed-infested triticale a field experiment was conducted at College of Agriculture and Natural Resources of Darab, Shiraz University in 2013-14 growing seas...

2013
Jicai Huang Yijun Gong Shigui Ruan Yuan Lou JICAI HUANG YIJUN GONG SHIGUI RUAN

In this paper we study the effect of constant-yield predator harvesting on the dynamics of a Leslie-Gower type predator-prey model. It is shown that the model has a Bogdanov-Takens singularity (cusp case) of codimension 3 or a weak focus of multiplicity two for some parameter values, respectively. Saddle-node bifurcation, repelling and attracting Bogdanov-Takens bifurcations, supercritical and ...

2014
Rudi Voss Martin F. Quaas Jörn O. Schmidt Julia Hoffmann

The maximum sustainable yield (MSY) is, theoretically, the largest yield that can be taken from a single species’ stock over an indefinite period. Formulation of strategic MSY management goals is, however, complicated by the need to move beyond biological single-species considerations. Interactions among species necessitate multispecies (MMSY) definitions, incorporating ecological, economic and...

Journal: :تولید گیاهان زراعی 0

the seedbed preparation and cereal residue present due to limit of maize (zea mays l.) growing period are a major challenge in double cropping after winter cereals in iran as: shahrekord. in this research, effects of various seedbed preparation methods and crop residuea managements on vegetative growth and yield of forage maize (ksc 704) were studied in a barley-maize double cropping during 200...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید