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The significant influences of substituting low concentration Dy at La- site for La0.667Sr0.333MnO3 perovskites compounds in structural, electrical and magnetoresistance properties have been studied. The polycrystalline samples (La1-xDyx)0.667Sr0.333MnO3 with x= 0.00, 0.02 and 0.10 were synthesized via conventional solid-state reaction in bulk. This work measured their resistivity properties with (below 1 Tesla) and without the presence of magnetic field (0 Tesla) as a function of temperature, microstructure and particle distribution and structural distortion using four point probe resistivity technique, X- ray diffractometer (XRD) and Atomic Force Microscope (AFM). The resistivity in applied magnetic field or so-called magnetoresistance ratio is defined as MR% = (Ro – RH)/RH x 100 was measured at 90K, 100K, 150K, 200K, 250K, 270K and 300K. The highest MR% values for x=0.00, 0.02 and 0.10 are 15.3%, 15.5% and 20.6% at 1 Tesla respectively. The metal- insulator transition temperature, TMIT correspond to >300K, 298K and 230K of sample with x= 0.00, 0.02 and 0.10 respectively were observed from resistivitytemperature (R-T) curve.

Polycrystalline samples of La0.67Ba0.33(Mn1-xRux)O3 with x = 0, 0.05, 0.1, 0.15 and 0.2 have been prepared using solid state reaction. The effects of doping of Ru at Mn site on La-Ba-Mn- O ceramics, the characteristics and magnetotransport properties of CMR materials are investigated. The magnetoresistance (MR) effect is measured using the four point probe technique. The magnetoresistance defined as MR% = (Ro – RH)/RH x 100% was measured at a magnetic field of H ≤ 1T at 90K, 100K, 150K, 200K, 250K, 270K and 300K for the sample of doping x = 0, 0.05, 0.1, 0.15 and 0.2. Overall, MR drops slowly when temperature rises. All doping concentration gives small variation range (~2.7% to ~26.78%). The electrical property has determined by using standard four-point probe resistivity measurement in a temperature range of 30 K to 300 K. Metalinsulator transition temperature (Tp) shifted to lower temperatures as Ru doping is increased. In this paper the structural pattern and microstructure property have investigated via XRD. XRD patterns show that these systems are in orthorhombic distorted perovskite structures.

AbstractMated female Olesicampe geniculataeQuednau and Lim were released in St. John’s, Newfoundland, to establish a biological control against the mountain ash sawfly, Pristiphora geniculata(Hartig). Two hundred and fifty-nine females were released during 1981–1984 in a field cage constructed over a mountain ash tree and provided with thousands of host larvae; 171 females were released outside the cage in 1984. A second open release of 368 P. geniculatacocoons, obtained as larvae from the field cage and presumably parasitized by O. geniculatae, was made in 1986 at Pasadena in western Newfoundland. Olesicampe geniculataerapidly established in the St. John’s area where host populations dropped to insignificant levels by 1990. Island-wide monitoring during 1989 and 1990 indicated that O. geniculataehad spread to the west and south coasts, at rates as high as 50 km per year. Effective and persistent suppression of P. geniculataby O. geniculataeis anticipated.

AbstractAerially applied Thuricide 48LV, Thuricide 64B, Futura XLV, and water-based formulations of Bacillus thuringiensisBerliner var. kurstaki(B.t.), were tested for effectiveness to control the hemlock looper, Lambdina fiscellaria fiscellaria(Guen.), in balsam fir, Abies balsamea(L.) Mill., stands. Thuricide 64B, applied twice at a dosage of 30 Billion International Units (BIU) per hectare in 1.78 L/ha, was the most effective, reducing the larval population by 100%.