The effect of population structure, plant size, herbivory and reproductive potential on effective population size in the temperate epiphytic orchid, Sarcochilus australis

Distribution of plant size and reproductive success is investigated in the temperate epiphytic orchid Sarcochilus australis (Lindl.) Rchb. f. at Kinglake National Park, Victoria, in south-eastern Australia, and applied to estimating the effective population size. Plant size distribution (leaf number, length of longest leaf and number of flowers) was not normally distributed. Most individuals were vegetative and it is estimated that more than half of all individuals are too small to flower, however exceptionally large individuals even though rare are able to have more than one active inflorescence. Flowering probability is plant size dependent and follows a sigmoid curve. The minimum observed leaf size of a flowering individual was 26 mm, however these small individuals have a low probability of flowering ( 80 mm) have a much higher probability of flowering (90%). The effective population size (Ne) of the Kinglake population of Sarcochilus australis was estimated from the distribution of flower production, and shown to be small (Ne = 10–19%) and comparatively similar to some of the other published estimates of effective populations size in orchids. From this basic survey of size distribution in Sarcochilus australis it is predicted that genetic diversity is low

Call, challenge, and reformation

Preached at Edmonton, Alta, O 28 2001

A method for designing blended wing-body configurations for low wave drag

A procedure for tailoring a blended wing-body configuration to reduce its computed wave drag is described. The method utilizes an iterative algorithm within the framework of first-order linear theory. Four computed examples are included. In each case, the zero-lift wave drag was reduced without an increase in the drag due to lift

Trajectory fitting in function space with application to analytic modeling of surfaces

A theory for representing a parameter-dependent function as a function trajectory is described. Additionally, a theory for determining a piecewise analytic fit to the trajectory is described. An example is given that illustrates the application of the theory to generating a smooth surface through a discrete set of input cross-section shapes. A simple procedure for smoothing in the parameter direction is discussed, and a computed example is given. Application of the theory to aerodynamic surface modeling is demonstrated by applying it to a blended wing-fuselage surface

A simplified approach to axisymmetric dual-reflector antenna design

A procedure is described for designing dual reflector antennas. The analysis is developed by taking each reflector to be the envelope of its tangent planes. Rather than specifying the phase distribution in the emitted beam, the slopes of the emitted rays were specified. Thus, both the output wave shape and angular distribution of intensity can be specified. Computed examples include variations from both Cassegrain and Gregorian systems, permitting deviation from uniform source distributions and from parallel beam property of conventional systems

A procedure for computing surface wave trajectories on an inhomogeneous surface

Equations are derived for computing surface waves on smooth surfaces, including surfaces with a nonuniform wave speed. The prior literature dealt primarily with the theoretical development with little consideration given to computational methods, and examples were limited to waves on surfaces of simple analytic description, such as cones, spheres, and cylinders. The computational procedure presented is a relatively general method. Sample calculations illustrate the procedure for a class of practical shapes of the type that include aerodynamic and hydrodynamic surfaces. Equations are also included for computing the spreading of rays into a surrounding medium that will support waves

Diffracted and head waves associated with waves on nonseparable surfaces

A theory is presented for computing waves radiated from waves on a smooth surface. With the assumption that attention of the surface wave is due only to radiation and not to dissipation in the surface material, the radiation coefficient is derived in terms of the attenuation factor. The excitation coefficient is determined by the reciprocity condition. Formulas for the shape and the spreading of the radiated wave are derived, and some sample calculations are presented. An investigation of resonant phase matching for nonseparable surfaces is presented with a sample calculation. A discussion of how such calculations might be related to resonant frequencies of nonseparable thin shell structures is included. A description is given of nonseparable surfaces that can be modeled in the vector that facilitates use of the appropriate formulas of differential geometry