The method of IIynes and Coleman is modified to make it more adaptable and more consistent with their underlying assumptions. If most organisms comprising a community are univoltine and have approximately the same maximum size, the average standing crop can bc used to obtain a realistic estimate of annual production. The size frequency distdbution can be regarded as a first estimate of an "average cohort" when the number of "average cohorts" equals the number of size classes through which the organisms grow. If growth, in terms of the size units used, is assumed to bc linear, then numerical differences in adjacent size classes can be attributed to mortality. When all size classes are considered togcthcr, the effect of nonlinear growth on the cstimatc of annual production is not large. In contrast, a serious error is introduced if the organisms are not univoltine. When the growth pattern and generation time are known, it is relatively simple to modify the average size frequency distribution to improve the cstimatc of the "average cohort" and hence improve the estimate of annual production. A reply to the criticisms of Fagcr is included. * Dcnotcs a single cohort during the cmrsc of its development.

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A new thermodynamically stable, aperiodic "bricksand-mortar" (B&M) cellular mesophase structure is reported in PS 1 -b-(PI-b-PS 2 ) 3 miktoarm copolymer and PS homopolymer blends [PS 1 , long polystyrene; PI, poly(isoprene); PS 2 , short polystyrene], where PS comprises discrete hard "bricks" and PI the continuous soft "mortar". The mesophase is unique in its extreme domain volume fractions, its lack of positional order, and quasi-long-range orientational order. On the basis of this unusual mesophase structure, a series of PS-based thermoplastic elastomers are realized, combining rigidity from an exceptionally high content of discrete glassy PS domains (up to 82 wt %) and high extensibility with recoverable elasticity from a low content of continuous rubbery PI (down to 18 wt %). The new elastomers show sharp yielding behavior while maintaining good elasticity at large strains. Tensile-SAXS experiments reveal that voiding plays an important role for the mechanical behavior and voids can open/close reversibly with/without loading. Plastic deformation only results in a slight loss of recoverable elasticity.

We report the creation of highly asymmetric lamellar structures with a well-designed miktoarm star block copolymer of the S(IS')3 type, where S and S' are polystyrenes of different lengths and I is poly(isoprene). The domain spacing can be tuned continuously from 37 nm to over 300 nm when the miktoarm star block copolymer is blended with suitable molecular weight polystyrene homopolymers. Beyond the unbinding transition of the lamellar phase, extremely asymmetric lamellar structures were obtained with up to 97 wt % polystyrene, remarkably leaving the poly(isoprene) layers intact at only 3 wt %!

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