Performance evaluations of recursive and iterative algorithms for the Towers of Hanoi problem

A theorem concerning the relation between the Towers of Hanoi and the binary numbers is proven in this paper. From this theorem, an algorithm for the Towers of Hanoi problem follows. The performance evaluations of all existing recursive and iteative algorithms for the Towers of Hanoi problem show that the above iterative algorithm is the most efficient one in terms of time and space. Finally, it is shown that the binary representation of numbers completely characterizes the status of alln discs in each step.     

Shaping behavior in voice therapy

This study demonstrates the process of learning and shaping of behavior which occurs during a program of therapy for individuals with hyperfunctional hoarse voice quality. First a therapy program delineating the techniques and criteria to be used was written. The program was presented during 16 individual half-hour sessions over an eight-week period to three clients known to have vocal nodules. The clients' responses were charted at various points from audiotape recordings of each therapy session using a modification of the Boone-Prescott analysis system, to obtain data to demonstrate the learning processes. It was concluded that: (1) the client's behaviors in this vocal rehabilitation program reflected a learning process; (2) facilitating techniques were used to modify or shape behavior through successive approximations to the terminal goal; (3) self-evaluation is an important factor needed to bring about successful changes in behavior; (4) analysis of client's behaviors in relation to the learning process can aid in evaluating the effectiveness of the facilitating techniques; and (5) from such evaluation intraclient and interclient program changes are derived hopefully resulting in a greater success rate and maximum benefits from time spent in therapy.     

Dihydroergotamine and heparin or heparin alone for the prevention of postoperative thromboembolism in gynecology

Lens epithelial cells from rats aged 5 days were grown in long-term cultures. These cells age, differentiate and transform spontaneously. Morphological observations indicate five different stages (A-E). The epithelial character is lost after the first two passages. Elongated cells appearing afterwards are considered as cells that have started differentiation to fiberlike cells. Big flattened cells are considered as senescent cells that have lost theie proliferative capacity. Data from population kinetics also reflect these five stages. Chromosome analysis shows that three of the five stages are no longer diploid. Two alternative modes of spontaneous transformation are possible. The proliferative capacity of rat lens epithelial cells is higher than that of rat embryonic fibroblast systems.     

Synergistic effect of the Bacillus thuringiensis toxins CryIAa and CryIAc on the gypsy moth, Lymantria dispar

The insecticidal activity of toxins CryIAa, CryIAb, and CryIAc against Lymantria dispar (gypsy moth) and Bombyx mori (silkworm) was examined by force-feeding bioassays. Toxin CryIAa exhibited higher toxicity than toxins CryIAb and CryIAc for L. dispar and B. mori. To evaluate possible synergism among these toxins, bioassays were performed with mixtures of CryIAa and CryIAb, CryIAb and CryIAc, and CryIAa and CryIAc. Expected toxicity was calculated from the activity of each individual toxin and its proportion in the mixture by using the equation described by Tabashnik (B. E. Tabashnik, Appl. Environ. Microbiol. 58:3343-3346, 1992). Observed 50% growth-inhibitory doses were calculated from mixing experiments by probit analysis. In L. dispar bioassays, synergism was observed with a mixture of CryIAa and CryIAc while a mixture of CryIAa and CryIAb exhibited an antagonistic effect. No synergistic effect on B. mori was observed with any toxin combination. Voltage clamping assays of isolated L. dispar midguts also demonstrated that the mixture of CryIAa and CryIAc induced a greater slope of inhibition of short circuit current than did other toxin combinations.     

Heterogeneous expression of glycopeptide resistance in enterococci associated with transfer of vanB

In mating experiments using a clinical strain that constitutively expresses vanB-encoded glycopeptide resistance, resistance transfer was detectable at a frequency of <10(-7) transconjugants/donor. Vancomycin MICs for transconjugants were 2- to 10-fold lower than those for the donor; both inducibly and constitutively resistant transconjugants were obtained. These findings demonstrate that the transfer of vanB among enterococci can be associated with substantial alterations in the level and control of glycopeptide resistance expression.