A mathematical model to investigate the demographic viability of low-density samango monkey (Cercopithecus mitis) populations in Natal, South Africa

Mass emergences of moths from conspicuous gregarious-phase caterpillars in high densities are important sources of migrant moths, which are borne downwind to cause a progression of armyworm outbreaks northwards from Tanzania to Ethiopia, and southwards from Rhodesia to South Africa. This progression might possibly be checked by destroying outbreak caterpillars. The sources of moths which cause the first outbreaks before the progression starts are not known, and the possibility is examined that these come from scattered populations of solitary-phase caterpillars hidden at the bases of green grasses, where they are sometimes found at considerable density. Recent analyses of weather patterns on the estimated dates of arrival of the moths responsible for fourteen groups of outbreaks in Rhodesia suggest that outbreaks could often be caused by convergent windflow concentratin glow-density moth populations from sources between Rhodesia and the Mozambique coast, and that these sources may persist for several months. A model is presented which attempts to relate the phase forms found in the field with the life system of the armyworm .

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The breeding requirements of three members of the Anopheles gambiae Giles complex (Diptera: Culicidae) in the endemic malaria area of Natal, South Africa

Bulletin of Entomological Research ◽

10.1017/s0007485300015418 ◽

1988 ◽

Vol 78 (4) ◽

pp. 549-560 ◽

Cited By ~ 15

Author(s):

David le Sueur ◽

Brian L. Sharp

Keyword(s):

South Africa ◽

Anopheles Gambiae ◽

Agricultural Development ◽

Low Density ◽

Freshwater Species ◽

Immature Stages ◽

Breeding Sites ◽

Endemic Malaria ◽

Anopheles Gambiae Giles ◽

Insecticide Spray

AbstractThe breeding sites used by three species of the Anopheles gambiae Giles complex were investigated in northern Natal, South Africa. Those used by the two freshwater species, A. arabiensis Patton and A. quadriannulatus (Theobald) were similar, immature stages of both being collected from the same pool at five out of seven localities from which A. arabiensis was recorded. A. quadriannulatus was the most extensively distributed species of the complex and was found in association with A. arabiensis at only five of 49 localities. The difficulty in locating the breeding sites of A. arabiensis is a product of their low density, presumably as a result of the intra-domiciliary, residual insecticide spray programme. A. merus Dönitz larvae and pupae were recorded only in water with a salinity greater than 5 p.p.t. The pH, dissolved oxygen, pool size, turbidity, shade and association with vegetation of water bodies containing A. gambiae s.l. were also recorded and showed no difference between the three species. The importance of distinguishing between winter and summer breeding sites is discussed, as well as the need for entomological consultation prior to agricultural development in endemic malarious areas.

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A mathematical model for the production of low density polyethylene in a tubular reactor

Chemical Engineering Science ◽

10.1016/0009-2509(86)87189-5 ◽

1986 ◽

Vol 41 (4) ◽

pp. 1031-1038 ◽

Cited By ~ 21

Author(s):

P.P. Shirodkar ◽

G.O. Tsien

Keyword(s):

Mathematical Model ◽

Tubular Reactor ◽

Low Density Polyethylene ◽

Low Density

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Design and Modeling of a Novel In-Pipe Microrobot Using IPMC Actuators

ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis, Volume 5 ◽

10.1115/esda2010-24755 ◽

2010 ◽

Author(s):

Meisam Vahabi ◽

Emad Mehdizadeh ◽

Mansour Kabganian ◽

Farshad Barazandeh

Keyword(s):

Mathematical Model ◽

Nonlinear Model ◽

Low Density ◽

Excitation Voltage ◽

Hamilton Principle ◽

Motion Type ◽

Modeling Simulation ◽

Modeling Process ◽

Simulation And Control ◽

And Control

Majority of researchers’ activities in microrobotics and MEMS fields has been devoted to fabrication processes and design. Lack of work on modeling, simulation and control is considerable. From the viewpoint of motion type, the most significant microrobots are the in-pipe ones. Some of the applications for the in-pipe microrobots are nozzle inspection, endoscopy, colonoscopy etc. IPMC is a new actuator in the class of EAPs. Large bending deflection, mechanical flexibility, low excitation voltage and low density make IPMC a very momentous actuator. This paper presents a new in-pipe microrobot that makes use of IPMC actuators to move the microrobot. Mathematical model of the microrobot is obtained using the extended Hamilton principle. This microrobot motion has four steps in every single movement cycle for which only two feet take part in each step. Thus the modeling process has to be done for the different steps apart. This problem considerably increases the complexity of the model. Another source that complexes the modeling process is due to the nonlinear model of IPMC actuator. Also the influence of IPMC actuators at each other has been examined.

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