The paper is concerned with the bifurcation of limit cycles in general quadratic perturbations of a quadratic reversible and non-Hamiltonian system, whose period annulus is bounded by an elliptic separatrix related to a singularity at infinity in the poincar'{e} disk. Attention goes to the number of limit cycles produced by the period annulus under perturbations. By using the appropriate Picard...

Hirsutella rhossiliensis and H. minnesotensis are endoparasitic fungi of the second-stage juvenile (J2) of the soybean cyst nematode (Heterodera glycines) in nature. They also parasitize both H. glycines J2 and Caenorhabditis elegans on agar plates. Agrobacterium tumefaciens-mediated transformation conditions were established for these Hirsutella spp. The resulting transformants were similar to...

Using the density matrix renormalization group technique, we study the ground state phase diagram and other low-energy properties of an isotropic antiferromagnetic spin-half chain with both dimerization and frustration, i.e., an alternation δ of the nearest neighbor exchanges and a next-nearest-neighbor exchange J2 . For δ = 0, the system is gapless for J2 < J2c and has a gap for J2 > J2c where...

culture filtrates (cf) of two species of the nematophagous fungi, arthrobotrys oligospora and arthrobotrys conoidesat three concentrations (25%, 50% and 100%) of stock, were tested on the mortality of second stage juveniles (j2) and egg hatching rate of meloidogyne incognita and meloidogyne javanica. results showed that the percent juvenile mortality was directly proportional to concentration o...

We study the dynamics of classical solutions a two-stage structured population model with nonlocal dispersal in spatially heterogeneous environment and address question persistence species. In particular, we show that species’ is completely determined by sign principal spectrum point, λp, linearized system at trivial solution: species goes extinct if λp≤0, while it persists uniformly space λp&g...

An L(2, 1)-labeling of a graph G = (V,E) is a function f : V → {0, 1, 2, . . .} such that |f(x)− f(y)| ≤ 2 if d(x, y) = 2 and |f(x)− f(y)| ≤ 1 if d(x, y) = 2. The span of an L(2, 1)-labeling is the maximum value f(x) among all vertices x in V . The L(2, 1)labeling number of G, denoted by λ(G) is the minimum span of an L(2, 1)-labeling. A more general setting is as follows. For positive integers...

Second-stage juveniles (J2) of races 1 and 2 of Meloidogyne chiiwoodi and M. hapla readily penetrated roots of Thor alfalfa and Columbian tomato seedlings; however, few individuals of M. chitwoodi race 1 were able to establish feeding sites and mature on alfalfa. Histopathological studies indicate that J2 of race 1 either failed to initiate feeding sites or they caused cell enlargement without ...

The breakdown of brassicaceous plant material produces nematotoxic isothiocyanates (ITCs). However, after the incorporation of brassicaceous plant material into soil, many nematodes are likely to be exposed only to sublethal concentrations of these compounds. Although unknown, the effect of these low ITC concentrations on the behaviour of plant-parasitic nematodes could play a role in nematode ...

The problem arises from the channel assignment problem. An L(2, 1)-labeling of a graph G = (V,E) is a function f : V → {0, 1, 2, . . .} such that |f(x) − f(y)| ≤ 2 if d(x, y) = 2 and |f(x) − f(y)| ≤ 1 if d(x, y) = 2. The span of an L(2, 1)-labeling is the maximum value f(x) among all vertices x in V . The L(2, 1)-labeling number of G, denoted by λ(G) is the minimum span of an L(2, 1)-labeling. ...

Some studies suggest that entomopathogenic nematodes (EPN) affect plant-parasitic nematode populations. Here, the effects of live and dead IJ of Heterorhabditis bacteriophora JPM4, H. baujardi LPP7, Steinernema feltiae SN and S. carpocapsae All were evaluated against eggs and J2 of the plant-parasitic nematode Meloidogyne mayaguensis. According to treatment, 100 IJ were applied with 350 eggs, 3...