2,970 research outputs found
International payments imbalances of the East Asian developing economies
East Asia ; Developing countries ; Economic policy ; Balance of payments ; Balance of trade ; Econometric models
Solid state remote power controllers for 120 VDC power systems
Solid state remote power controllers can be applied to any dc power system up to 120 Vdc and distribute power up to 3.6 kW per hour. Devices have demonstrated total electrical efficiencies of 98.5 percent to 99.0 percent at rated load currents
Perturbed angular correlation study of a haptenic molecule
The angular correlation of the 173-247 keV gamma-ray cascade after the electron-capture decay of (111)In is strongly perturbed when the I-p-nitrophenylethylenediaminetetraacetate chelate of (111)In(3+) is added to a solution containing rabbit antibody to dinitrophenyl groups. The radioactive chelate can be displaced by the addition of dinitrophenyllysine or unlabeled chelate. The average association constant between the antibody and the labeled chelate has been estimated from perturbed angular correlation measurements; this value is compared to the results of equilibrium dialysis. These experiments provide good evidence that information concerning macromolecular behavior can be obtained from perturbed angular correlation experiments that use chemically specific labels
Initiation and Early Development of Axillary Buds in Cyclamen
The development of axillary buds along the primary shoot axis of Cyclamen persicum Mill. F-1 Rosemunde .was examined. Vegetative buds usually formed in the axils of the cotyledon and first 5 leaves. Flowers were produced from the majority of the buds which developed in the axils of later-formed leaves. The first indication of vegetative bud development was the appearance of a shell zone. Proliferation of the cells set off by this zone soon led to the establishment of a branch shoot apex producing leaf primordia. Formation of a shell zone was not associated with the initiation of floral buds. These ·arose as a detached meristem and the proliferation of the axillary cells soon led to the establishment of an apical organization. Vigorous activity of the rib meristem and its derivatives initiated rapid peduncle growth. The differentiation of initials into vegetative vs reproductive buds may be due to different environmental conditions influenced by the subtending and adjacent leaves, as well as to cytological differences between the cells of the respective shoot apices
Organization of the Primary Body in the Root of Cyclamen persicum Mill
The primary body of the root of Cyclamen persicum Mill. is described. The rootcap consists of two components of separate origin. Cells of the columella are derived from the dermatocalyptrogen by periclinal wall formation. Further growth of the columella is due primarily to the increase in size of existing cells. Cells of the lateral rootcap arise from the protoderm by periclinal wall formation. Continued growth in this region is due to both increase in cell number and increase in size of existing cells. Proximal to the dermatocalyptrogen is the presumptive quiescent center. Around the periphery of this zone are located the initials of the ground meristem and procambium
Some Optimal Growth Media For Use In The Botany Classroom
Cultures of various bacteria and fungi are often used in introductory botany classes. In most cases the students are simply asked to examine these colonies or to prepare a microscope slide. Directions are given in this paper for the preparation of optimal growth media which may be consumed by the student. This provides a new twist to otherwise routine laboratory exercises
Pollen of the Myricaceae - a Preliminary Report
Pollen of 16 species and one variety of the Myricaceae was examined, including members of each of the genera proposed by Chevalier (1901) in addition to Canacomyrica (Guillaumin, 1939). Comparison of pollen characters within genera, within sections, between sections, and between genera suggests that the Myricaceae can be divided into four genera: Canacomyrica; Comptonia; Gale; and Myrica. The genus Myrica can be further divided into three sections; Cerophora, Fava, and Morella
The Elongation of the Leaf of Cyclamen persicum Mill. (Cultivars)
The leaves of three cultivars of Cyclamen persicum were examined at several stages of development in order to determine the pattern of elongation in both the lamina and petiole. Although there is a considerable literature on lamina elongation, relatively little is known about the growth of the petiole. In the latter structure it is usually assumed that an intercalary meristem is involved. Elongation of the young leaf is initially due to activity distributed throughout the deve1opint organ. Maturation of the leaf progresses acropetally from the base of the petiole and basipetally from the tip of the lamina. As the leaf matures elongation in both the lamina and petiole becomes restricted to their region of common attachment
Logic-controlled solid state switchgear for 270 volts dc
A feasibility study to design and demonstrate solid state switchgear in the form of circuit breakers and a power transfer switch is described. The switchgear operates on a nominal 270 V dc circuit and controls power to a load of up to 15 amperes. One circuit breaker may be interconnected to a second breaker to form a power transfer switch. On-off and transfer functions of the breakers or the transfer switch are remotely controlled. A number of reclosures with variable time delay between tripout and reclosure are programmed and controlled by integrated analog and COSMOS logic circuits. A unique commutation circuit, that generates only minimal transient disturbance to either source or load, was developed to interrupt current flow through the main SCR switching element. Laboratory tests demonstrated performance of the solid state circuit breakers over specified voltage and temperature ranges
- …