The Status of Bacillus thuringiensis

Author(s):  
A. M. HEIMPEL
Pesticidi ◽  
2003 ◽  
Vol 18 (2) ◽  
pp. 69-75 ◽  
Author(s):  
Nenad Filajdic ◽  
Petar Vuksa ◽  
Mirko Ivanovic ◽  
Emil Rekanovic

The idea of fighting pathogens, pests, and weeds by biological measures is not new. Only recently, however, has the need for this aspect of crop protection and related bioproducts arisen. Increasingly stricter legislation concerning pesticides and new information about their potential harmfulness have narrowed the scope of products, offered by large agrochemical companies, thus reducing the prospects of successful and profitable crop protection. In addition, there has been a high risk of resistance of harmful organisms to classical pesticides which throws new light on problems that the industry of chemical pesticides encounters. The control of harmful insects by bioproducts has been a matter of utmost interest, mainly due to a relative success of products, based on Bacillus thuringiensis. However there has been a few more successful attempts of developing biological fungicides, nematocides, and herbicides in the last decade. Still, crop protection products, based on living organisms, represent a small portion of total pesticide industry which amounts to approximately 32 billion dollars per year (Warrior, 2000). The majority of living organisms, been investigated with purpose of biological control, belongs to fungi, bacteria, or arthropods. Commercially, the number of those applied in biopesticides is small, especially because of limitations, imposed on reproduction and stability of organisms in storage and formulation of biopesticides. The aim of this paper is to describe the status of biological control in crop protection, problems encountered, and perspectives of its future development.


Author(s):  
L.J. Chen ◽  
Y.F. Hsieh

One measure of the maturity of a device technology is the ease and reliability of applying contact metallurgy. Compared to metal contact of silicon, the status of GaAs metallization is still at its primitive stage. With the advent of GaAs MESFET and integrated circuits, very stringent requirements were placed on their metal contacts. During the past few years, extensive researches have been conducted in the area of Au-Ge-Ni in order to lower contact resistances and improve uniformity. In this paper, we report the results of TEM study of interfacial reactions between Ni and GaAs as part of the attempt to understand the role of nickel in Au-Ge-Ni contact of GaAs.N-type, Si-doped, (001) oriented GaAs wafers, 15 mil in thickness, were grown by gradient-freeze method. Nickel thin films, 300Å in thickness, were e-gun deposited on GaAs wafers. The samples were then annealed in dry N2 in a 3-zone diffusion furnace at temperatures 200°C - 600°C for 5-180 minutes. Thin foils for TEM examinations were prepared by chemical polishing from the GaA.s side. TEM investigations were performed with JE0L- 100B and JE0L-200CX electron microscopes.


Author(s):  
Frank J. Longo

Measurement of the egg's electrical activity, the fertilization potential or the activation current (in voltage clamped eggs), provides a means of detecting the earliest perceivable response of the egg to the fertilizing sperm. By using the electrical physiological record as a “real time” indicator of the instant of electrical continuity between the gametes, eggs can be inseminated with sperm at lower, more physiological densities, thereby assuring that only one sperm interacts with the egg. Integrating techniques of intracellular electrophysiological recording, video-imaging, and electron microscopy, we are able to identify the fertilizing sperm precisely and correlate the status of gamete organelles with the first indication (fertilization potential/activation current) of the egg's response to the attached sperm. Hence, this integrated system provides improved temporal and spatial resolution of morphological changes at the site of gamete interaction, under a variety of experimental conditions. Using these integrated techniques, we have investigated when sperm-egg plasma membrane fusion occurs in sea urchins with respect to the onset of the egg's change in electrical activity.


2000 ◽  
Vol 64 (11) ◽  
pp. 772-774 ◽  
Author(s):  
JG Odom ◽  
PL Beemsterboer ◽  
TD Pate ◽  
NK Haden

2002 ◽  
Vol 110 (2) ◽  
pp. 9-15 ◽  
Author(s):  
W Freedman
Keyword(s):  

1998 ◽  
Vol 14 (1) ◽  
pp. 62-70 ◽  
Author(s):  
Richard H. Dana

This paper describes the status of multicultural assessment training, research, and practice in the United States. Racism, politicization of issues, and demands for equity in assessment of psychopathology and personality description have created a climate of controversy. Some sources of bias provide an introduction to major assessment issues including service delivery, moderator variables, modifications of standard tests, development of culture-specific tests, personality theory and cultural/racial identity description, cultural formulations for psychiatric diagnosis, and use of findings, particularly in therapeutic assessment. An assessment-intervention model summarizes this paper and suggests dimensions that compel practitioners to ask questions meriting research attention and providing avenues for developments of culturally competent practice.


1962 ◽  
Vol 7 (4) ◽  
pp. 156-156
Author(s):  
C. SHAGASS

1990 ◽  
Vol 35 (10) ◽  
pp. 982-983
Author(s):  
Gail M. Williamson
Keyword(s):  

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