Modelling the Influence of Climatic Factors on the Population Dynamics of Radopholus Similis: Banana-Plantain Pest.

Radopholus Similis (R. Similis) or burrowing nematode, is one of the most damaging and widespread nematodes attacking bananas, causing toppling or blackhead disease. A mathematical model for the population dynamics of R. Similis is considered, with the aim of investigating the impact of climatic factors on the growth of R. Similis. In this paper, based on the life cycle of R. Similis, we first propose a mathematical model to study and control the population dynamics of this banana pest. We show also how control terms based on biological and chemical controls can be integrated to reduce the population of R. Similis within banana-plantain roots. Sensitivity analysis was performed to show the most important parameters of the model. We present the theoretical analysis of the model. More precisely, we derive a threshold parameter [Formula: see text], called the basic offspring number and show that the trivial equilibrium is globally asymptotically stable whenever [Formula: see text], while when [Formula: see text], the non trivial equilibrium is globally asymptotically stable. After, we extend the proposed model by taking account climatic factors that influence the growth of this pest. Biological and chemical controls are now introduced through impulsive equations. Threshold and equilibria are obtained and global stabilities have been studied. The theoretical results are supported by numerical simulations. Numerical results of model with biological and chemical controls reveal that biological methods are more effective than chemical methods. We also found that the month February is the best time to apply these controls.

[Remarkable evolution of hepatic, pleural and pulmonary amoebiasis: a case report]. / Evolution spectaculaire d'une amibiase hépatique et pleuropulmonaire: à propos d'un cas.

Entamoeba histolytica, is a human pathogen which is endemic in tropical areas. The most common extra-intestinal locations for disease after the liver are pleural and pulmonary. Although the outcome of pleural and pulmonary amoebiasis is generally favourable, it is important to note that a significant proportion of patients do develop pleural and pulmonary after-effects. We report a case of pleural and pulmonary amoebiasis where the evolution of a massive pleural effusion and 3 associated liver abscesses was spectacular. The surgical management of pleural, pulmonary and liver amoebiasis is discussed.

Halichondria sulfonic acid, a new HIV-1 inhibitory guanidino-sulfonic acid, and halistanol sulfate isolated from the marine sponge Halichondria rugosa Ridley & Dendy.

A new sulfur-containing guanidino derivative, halichondria sulfonic acid (1) showing anti-HIV-1 activity, and halistanol trisulfate (2) with anti-tumor activity have been isolated from the marine sponge Halichondria rugosa Ridley & Dendy collected in the Chinese Southern Sea. The structure of 1 was elucidated by analysis of spectroscopic and crystal data.