Survey and molecular characterization of Hop stunt viroid (HSVd) sequence variants from citrus groves in Morocco

Viroids are the smallest known pathogens of plants. They are single-stranded, circular, rod-like RNAs with no protein capsid no any detectable messenger activity. Citrus is one of the most important commercial fruit crops grown in Morocco. Seven viroids reported to infect Citrus spp. belong to four genera of the family Pospiviroidae. Hop stunt viroid (HSVd) belongs to genus Hostuviroid and consists of a 295-303 nucleotides circular single-stranded RNA. It has been found in a wide range of hosts including several woody and herbaceous crops. Cachexia, an economically important disease of citrus, has been associated with HSVd infection. HSVd isolates are divided into five phylogenetic groups according to the sequence variants: plum-type, hop-type, citrus-type, plum-citrus-type and plum-hop-citrus-type. In this work we present the molecular characterization of six new sequence variants of HSVd obtained from the main Moroccan citrus growing areas: Gharb, Haouz, Loukkos, Moulouya, Souss and Tadla, respectively. The genetic diversity among the Moroccan variants was investigated. Phylogenetic analysis showed that Moroccan citrus HSVd variants were clustered into one group within the citrus-type and the sequence variability seems neither related to the host nor to symptomatology. Despite an accumulation of nucleotide changes, the secondary structure of the viroid mol­ecule was conserved. Since citrus viroids are readily mechanically transmissible via working tools, they affect both old and young plantings in all the citrus groves surveyed. Keywords: Hop stund viroid, Survey, Molecular characterization, Morocc

Fixed Coefficients Block Backward Differentiation Formulas for the Numerical Solution of Stiff Ordinary Differential Equations

This paper focuses on the derivation of implicit 2-point block method based on Backward Differentiation Formula (BDF) which will be called BBDF of variable step size for solving first order stiff initial value problems (IVPs) for Ordinary Differential Equations (ODEs). The method presented is similar to the form of standard BDF. This allows us to store the coefficients of the y values and thus avoiding calculating the differentiation coefficients at each step but robust enough to allow for step size variation.Plots of their regions of absolute stability for the method are also presented. The efficiency of the 2-point BBDF is compared with the conventional variable step variable order BDF(VSVOBDF) method. Numerical results indicate that the resulting 2-point BBDF method outperform the VSVOBDF method in both execution time and accuracy

Numerical solution of differential algebraic equations (DAEs) by mix-multistep method

Differential Algebraic Equations (DAEs) are regarded as stiff Ordinary Differential Equations (ODEs). Therefore they are solved using implicit method such as Backward Differentiation Formula (BDF) type of methods which require the use of Newton iteration which need much computational effort. However, not all of the ODEs in DAE system are stiff. In this paper, we describe a new technique for solving DAE, where the ODEs are treated as non-stiff at the start of the integration and putting the non-stiff ODEs into stiff subsystem should instability occurs. Adams type of method is used to solve the non-stiff part and BDF method for solving the stiff part. This strategy is shown to be competitive in terms of computational effort and accuracy. Numerical experiments are presented to validate its efficiency

The uterine choriocarcinoma in postmenopausal women: specificities of diagnosis and treatment

Choriocarcinoma is a gestational trophoblastic tumor that mainly affects women of childbearing age. Cases of choriocarcinoma in postmenopausal women are exceptional. Through an observation and literature review, we propose to study the specific diagnosis and treatment features of this tumor in menopausal women. We report the observation of a pure uterine choriocarcinoma, which occurred in post-menopause. The diagnosis was made on the analysis of surgical specimens confirmed by measurement of hCG. Chemotherapy was started after a total hysterectomy and bilateral salpingo-oophorectomy first. The improvement was dramatic after 3 courses of chemotherapy and the patient is in complete remission after five years of monitoring. The primitive forms of pure choriocarcinoma in postmenopausal women are exceptional. Their etiology is poorly understood and their treatment based on chemotherapy.Key words: Uterine choriocarcinoma; post menopause; gestational trophoblastic tumo

Penyelesaian persamaan pembezaan biasa kaku menggunakan kaedah blok formulasi beza ke belakang.

Kertas kerja ini membincangkan kaedah Blok Formulasi Beza Ke Belakang (BFBB) bagi menyelesaikan persamaan pembezaan biasa (PPB) jenis kaku. Umumnya, persamaan jenis kaku diselesaikan dengan kaedah tersirat yang melibatkan lelaran Newton yang mengambil masa pengiraan yang panjang. Dengan yang demikian, suatu kaedah blok dua titik menggunakan saiz langkah berubah dibangunkan berdasarkan Formulasi Beza Ke Belakang (FBB). Sebelum ini pengiraan beza pembahagi yang berulangkali dan rumit dilakukan pada setiap langkah dalam pengiraan pekali pembezaan,tetapi dalam kod yang dibangunkan, pengiraan pekali pembezaan hanya dilakukan pada langkah awal sahaja. Dipaparkan perbandingan keputusan berangka antara BFBB dan FBB yang menunjukkan keberkesanan dalam mengurangkan masa pengiraan dan kejituan penyelesaian yang lebih baik apabila kaedah BFBB di gunakan dalam menyelesaikan masalah nilai awal PPB kaku

Diagonally implicit block backward differentiation formulas for solving fuzzy differential equations

In this work, the diagonally implicit 2-points block backward differentiation formulas (DIBBDF) is developed for solving Fuzzy Differential Equations (FDEs) under the interpretation of generalized Hukuhara differentiability. The fuzzy configuration of this method is also introduced. Numerical results using DIBBDF are presented and compared with the existing method. It is clearly shown that the proposed method obtains good numerical results and suitable for solving FDEs

On the stability of diagonally implicit 2-point block backward differentiation formulae

In this work, the zero-stability properties of diagonally implicit 2-point block backward differentiation formulas (DI2BBDF) are presented. The stability region is illustrated to prove the A-stable behavior. Some numerical stiff problems are provided to test the performance of the method in terms of accuracy. Numerical results are compared with the fully implicit 2-point block backward differentiation formulas (FI2BBDF)

Certification scheme for fig plants (Ficus carica L.) in Morocco

Le programme de certification et d’assainissement des plants de figuier ont pour objectif la production des plants dont l’authenticité variétale est reconnue,  indemnes de virus et d’autres pathogènes. Au Maroc, ce système de certification comprend des indications détaillées sur la production des plants de figuier à multiplication végétative. L’organisation de la certification dans ses différentes étapes est détaillée, les organismes sollicités et le contrôle sanitaire garantissant des plants certifiés indemnes de maladies virales causant la mosaïque du figuier sont décrits. Ce programme implique les secteurs de la recherche, les institutions publiques, les sociétés privées, les pépiniéristes Marocains, afin de mettre en place un système de certification phytosanitaire du figuier. Mots-clés: Figuier, certification, virus, authenticité variétale, Maroc.  Certification and sanitation programs for pathogen-tested material of the fig tree have the aim of providing plants that are true-to-type, free from virus and substantially free from other pests. In Morocco, this certification scheme provides detailed guidance on the production of vegetative propagated fig plants. The organization of certification through its steps is detailed and the agencies involved in the sanitary controls, which guarantee the freedom of certified stocks from virus causing mosaic on fig plants are described. This program involves the sectors of research, public institutions and Moroccan nurseries in order to set up a system of sanitary certification of fig tree in Morocco. Keywords: Fig plants, certification, virus, trueness-to-type, Morocco

Mammary-like adenocarcinoma of the vulva associated to Paget’s disease: a case report

Mammary-like adenocarcinoma of the vulva associated to Paget's disease is exceedingly rare. So, it is very important to perform all the pathological and immunohistochemical investigations to achieve differential  diagnosis from both a metastatic lesion from an orthotopic breast cancer and a vulvar adnexal tumor. This report describes a case of vulvar Paget's disease associated with underlying mammary-like adenocarcinoma diagnosed in the Department of Obstetrics and Gynecology of Farhat Hached university hospital of Sousse in Tunisia. We also review previously reported cases of primary breast-like carcinoma of the vulva with or without Paget's diseaseKey words: Mammary-like adenocarcinoma, vulva, Paget´s diseas

3-point block backward differentiation formulas for solving fuzzy differential equations

In this paper, 3-point Block Backward Differentiation Formulas (3BBDF) is used for the numerical solution of Fuzzy Differential Equations (FDEs). Implementation of 3BBDF using Newton iteration is discussed. Numerical results obtained by the 3BBDF are presented and compared with the Modified Simpson method to illustrate the ability of the 3BBDF method for solving FDEs