Absrrt7c.r: Althul~gh winter foods o f mallards (Annsplat~rh~t tcos) and wood ducks (Aix sporlscl) have been documented in several studies, 110 stich research has been conducted in nati~ral bottomland hardwood forests in eastern 'Texas. We collected 40 mallards and 78 woocl dticks and san~pleil available foods in eastern Texas during winters 1987-1988 and 1988-89 to study food habits and prefer...

Yeast Saccharomyces cerevisiae strains that are permeable to the antitumor alkaloid camptothecin are killed by the drug if they express DNA topoisomerase I, the cellular target of the drug (J. Nitiss and J. C. Wang, Proc. Nati. Acad. Sci. USA, «5.-7501-7505,1988). We show that in a yeast strain permeable to camptothecin but lacking DNA topoisom erase I, sensitivity to the drug was restored upo...

Using newly available food composition data for carotenoids, the authors reanalyzed a population-based case-control study of diet and lung cancer conducted in Hawaii in 1983-1985 (1. Le Marchand et a!., J. NatI. Cancer Inst., 81: 1158-1164, 1989). The analysis included interviews with 230 men and 102 women with lung cancer and 597 men and 268 women as controls, frequency-matched to the patients...

Ditercalinium (NSC 335153), a bifunctional intercalating molecule with antitumor activity, is found to express its toxicity through a mech anism of action completely different from that of other monointercalating agents. Electron microscopic observation of ditercalinium-treated cells shows a drastic alteration of mitochondria! structure. Cells deficient in mito chondria! respiration (GSK3 cells...

Let V be an rn-dimensional linear subspace of Zn 2 . Suppose the smallest Hamming weight of non-zero vectors in V is d. (In coding-theoretic terminology, V is a linear code of length n, rate r and distance d.) We settle two extremal problems on such spaces. First we prove a (weak form) of a conjecture by Kalai and Linial and show that the fraction of vectors in V with weight d is exponentially ...

1. J. P. Allison and L. L. Lanier, Annu. Rev. Immunol. 5, 503 (1987); A. Weiss and J. B. Imboden, Adv. Immunol. 41, 1 (1987). 2. L. E. Samelson and M. D. Patel, Cell 46, 1083 (1986); J. B. Imboden and J. D. Stobo, J. Exp. Med. 161, 446 (1985). 3. T. A. Springer, M. L. Dustin, T. K. Kishimoto, S. D. Marlin, Annu. Rev. Immunol. 5, 223 (1987); D. R. Littman, ibid., p. 561. 4. T. Hara et al., J. Ex...

We reported previously that circularly permuted interIeukin-4 (IL4), composed of amino acids 38-129 of IL4 connected by a linker peptide GGNGG to amino acids 1-37, is preferable to native II ,4 for fusing to the amino terminus of truncated Pseudomonas exotoxin (PE) to make a recombinant toxin, because the new ligand-toxin junction results in im proved IL4 receptor (IL4R)-binding (R. J. Kreitman...

It has been over two decades since Group Support Systems (GSS) emerged on the Information Technology (IT) scene. GSS have now been commercialized and are present in an increasing number of domestic and international contexts but only lightly studied in real organizational settings. A criticism of studies has been that many of the organizations involved had a vested interest in the outcome that ...

Two genres of heuristics that are frequently reported to perform much better on “real-world” instances than in the worst case are greedy algorithms and local search algorithms. In this paper, we systematically study these two types of algorithms for the problem of maximizing a monotone submodular set function subject to downward-closed feasibility constraints. We consider perturbation-stable in...

Anilino analogues of amsacrine showed increased activity against amsacrine (AMSA)-resistant cell lines when compared with the parent compound, but the mechanisms of amsacrine resistance in these lines wereunknown(Finlay, G. J., Baguley,B. C., Snow,K., and Judd, W., J. NatI. Cancer Inst., 82: 662—667, 1990). We tested the cytotoxic and DNA-cleaving activities of two amsacrine analogues which w...