The 1990-91 Taulbee survey report [computer science education]

The key findings of the 1990-91 Taulbee Survey Report describing the results of a study of the Forsythe list of computing departments are presented. The Forsythe list enumerates all departments in the US and Canada that grant PhDs in computing, specifically in computer science (CS) and computer engineering (CE). Completed in December 1991, the latest survey concerns the production and employment of PhDs who graduated in 1990-91 and the faculty of PhD-granting computing departments during the 1991-92 academic year. The results indicate that the production of PhDs in CS departments increased significantly; the number of faculty in PhD-granting departments leveled off for the first time in two decades; those departments employed more full professors than assistant professors for another first; and minority figures persisted on the low side     

Inhaled nitric oxide inhibits human platelet aggregation, P-selectin expression, and fibrinogen binding in vitro and in vivo

BACKGROUND: Recent data suggest that inhaled NO can inhibit platelet aggregation. This study investigates whether inhaled NO affects the expression level and avidity of platelet membrane receptors that mediate platelet adhesion and aggregation. METHODS AND RESULTS: In 30 healthy volunteers, platelet-rich plasma was incubated with an air/5% CO2 mixture containing 0, 100, 450, and 884 ppm inhaled NO. ADP- and collagen-induced platelet aggregation, the membrane expression of P-selectin, and the binding of fibrinogen to the platelet glycoprotein (GP) IIb/IIIa receptor were determined before (t0) and during the 240 minutes of incubation. In addition, eight patients suffering from severe adult respiratory distress syndrome (ARDS) were investigated before and 120 minutes after the beginning of administration of 10 ppm inhaled NO. In vitro, NO led to a dose-dependent inhibition of both ADP-induced (3+/-3% at 884 ppm versus 70+/-6% at 0 ppm after 240 minutes; P<.001) and collagen-induced (13+/-5% versus 62+/-5%; P<.01) platelet aggregation. Furthermore, P-selectin expression (36+/-7% of t0 value; P<.01) and fibrinogen binding (33+/-11%; P<.01) were inhibited. In patients with ARDS, after two who did not respond to NO inhalation with an improvement in oxygenation had been excluded, an increase in plasma cGMP, prolongation of in vitro bleeding time, and inhibition of platelet aggregation and P-selectin expression were observed, and fibrinogen binding was also inhibited (19+/-7% versus 30+/-8%; P<.05). CONCLUSIONS: NO-dependent inhibition of platelet aggregation may be caused by a decrease in fibrinogen binding to the platelet GP IIb/IIIa receptor.     

Optical isomers of 3,13-dimethylheptadecane: Sex pheromone components of the western false hemlock looper,Nepytia freemani (Lepidoptera: Geometridae)

(3S, 13R)-3, 13-Dimethylheptadecane [(3S, 13R)-3, 13-dime-17Hy] is the major pheromone component of the western false hemlock looper (WFHL),Nepytia freemani. In comparative gas chromotographic-electroantennographic detection (GC-EAD) analyses of stereoselectively synthesized isomers, 1 pg of (3S, 13R)-dime-17Hy elicited significantly stronger electrophysiological responses by male WFHL antennae than did 1 pg of separately injected (3R, 13R)-, (3R, 13S)- or (3S, 13S)-3, 13-dime-17Hy. In field experiments with individually tested stereoisomers. (3S, 13R)-3, 13-dime-17Hy was the only stereoisomer to attract males, but the four-stereoisomer blend was 3.6 times more attractive. Quaternary and all binary combinations of (3S, 13R)-3, 13-dime-17Hy with the other stereoisomers were equally attractive, suggesting that synergisytic behavioral activity in WFHL resided with either one of (3R, 13R)-, (3R, 13S)-, or (3S, 13S)-3, 13-dime-17Hy. Because optical isomers of (di)methylhydrocarbons do not separate on currently available columns, it remains unknown whether female WFHL also produce a four-stereoisomer pheromone blend. Substitutionality of pheromone stereoisomers without loss of behavioural activity has not previously been reported, but favorably compares with the concept of pheromone redundancy that was first suggested for the multiple pheromone component blend of the cabbage looper moth,Trichoplusia ni.     

The Schorr-Waite graph marking algorithm

Summary An explanation is given of the Schorr-Waite algorithm for marking all nodes of a directed graph that are reachable from one given node, using the axiomatic method.This research was supported by the National Science Foundation under Grant MCS76-22360     

The 1986-7 Taulbee survey [computer science graduates, employmentsurvey]

The authors describe the results of a survey completed in December 1987 on the production and employment of PhDs and faculty of PhD-granting computer science/engineering departments during the academic year, 1986-7. All 123 computer science departments (111 US and 12 Canadian) participated. In addition, for the first time, 22 US departments offering the PhD in computer engineering (CE) were included. CE statistics are reported separately so that comparisons with previous years can be made for computer science (CS), but the intention is to merge all statistics for CS and CE after several years     

Describing an algorithm by Hopcroft

We give an algorithm, its correctness proof, and its proof of execution time bound, for finding the sets of equivalent states in a deterministic finite state automaton. The time bound is K · m · n · log n where K is a constant, m the number of input, symbols, and n the number of states. Hopcroft [3] has already published such an algorithm. The main reason for this paper is to illustrate the use of communicating an algorithm to others using a structured, top-down approach. We have also been able to improve on Hopcroft's algorithm by reducing the size of the algorithm and correspondingly complicating the proof of the running time bound.This research was supported by NSF Grant No. GJ-28176.     

(2S,12Z)-2-Acetoxy-12-heptadecene: Major Sex Pheromone Component of Pistachio Twig Borer, Kermania pistaciella

The sex pheromone of the pistachio twig borer, Kermania pistaciella (Lepidoptera: Oinophilidae), one of the most important insect pests of pistachio, Pistacia vera, in Turkey and Iran, was identified. In gas chromatographic-electroantennographic detection (GC-EAD) and GC-mass spectrometric analyses of pheromone gland extracts of female K. pistaciella from Turkey, (2S,12Z)-2-acetoxy-12-heptadecene was identified as the major candidate pheromone component. In field experiments in Turkey, lures containing synthetic (2S,12Z)-2-acetoxy-12-heptadecene attracted large numbers of male moths. Its attractiveness was significantly reduced by the presence of the R-enantiomer or of either enantiomer of the corresponding alcohol. (2S,12Z)-2-Acetoxy-12-heptadecene is the first pheromone component identified in the Oinophilidae and the first secondary acetate pheromone component identified in the Lepidoptera. An erratum to this article can be found at     

False increased CK-MB value after cryoablation of the prostate without myocardial infarct

The authors report on a profound increase in creatine kinase isoenzyme MB (CK-MB) activity in three patients following uneventful cryoablation of the prostate under general anaesthesia: Just after the arrival at the recovery room CK-MB levels were 321 U/l, 245 U/l and 433 U/l, respectively. Other clinical investigations as well as additional laboratory tests ruled out myocardial infarction in all three patients. Electrophoresis of the CK-isoenzymes revealed an increase in CK-BB activity and an increase in atypical CK-BB as a cause of these findings. The presence of these isoenzymes leading to interferences with the antibody commonly used in CK-MB assays could explain the determination of a false positive CK-MB elevation in the three patients. Moreover, it is shown that this method of CK-MB activity determination may result in CK-MB levels higher than 100% of the whole CK activity. In addition, it is discussed that in patients suffering from prostatic carcinoma or other malignoma, "non-CK-M elevations" may occur. Therefore, the authors conclude that after cryoablation of the prostate additional tests like troponin T test and 12 channel ECG are required to rule out suspected myocardial infarction.     

Wafer-Scale Fabrication of Hierarchically Porous Silicon and Silica by Active Nanoparticle-Assisted Chemical Etching and Pseudomorphic Thermal Oxidation (Small 22/2023)

Many biological materials exhibit a multiscale porosity with small, mostly nanoscale pores as well as large, macroscopic capillaries to simultaneously achieve optimized mass transport capabilities and lightweight structures with large inner surfaces. Realizing such a hierarchical porosity in artificial materials necessitates often sophisticated and expensive top-down processing that limits scalability. Here, an approach that combines self-organized porosity based on metal-assisted chemical etching (MACE) with photolithographically induced macroporosity for the synthesis of single-crystalline silicon with a bimodal pore-size distribution is presented, i.e., hexagonally arranged cylindrical macropores with 1 µm diameter separated by walls that are traversed by pores 60 nm across. The MACE process is mainly guided by a metal-catalyzed reduction–oxidation reaction, where silver nanoparticles (AgNPs) serve as the catalyst. In this process, the AgNPs act as self-propelled particles that are constantly removing silicon along their trajectories. High-resolution X-ray imaging and electron tomography reveal a resulting large open porosity and inner surface for potential applications in high-performance energy storage, harvesting and conversion or for on-chip sensorics and actuorics. Finally, the hierarchically porous silicon membranes can be transformed structure-conserving by thermal oxidation into hierarchically porous amorphous silica, a material that could be of particular interest for opto-fluidic and (bio-)photonic applications due to its multiscale artificial vascularization.