cssi/SciSciGPT-SciSciNet huggingface dataset:
Optimal control of a stirred-tank reactor with rapidly-decaying catalyst

Abstract The singular perturbation solution to a general optimal control problem consisting of the optimization of a final-time function of the “slow” variables, subject to inequality control constraints in the inner control region, and a free-time terminal manifold for the fast-slow differential equations, is given. The example studied here is the optimal temperature control of a stirred-tank catalytic reactor in which the time constant of the catalyst decay is appreciable compared to the mean residence time. The first-order corrections to the usual quasi-steady state (zeroth-order outer) solution, consisting of the zeroth-order inner solutions at both ends of the interval of operation and the first-order outer solutions, are calculated. Boundary layers thus appear at start-up and shutdown. The second-order corrections can be calculated by the methods given here, and would entail interior boundary layers around the entry points to the control constraints. These entry points are not fixed in time, and a time-scaling procedure, developed previously for converting free-time to fixed-time problems, is employed. The solutions are thus matched at the edges of the boundary layers, and around the inequality-constraint entry and exit points. Some numerical solutions are given which show an appreciable increase in return on investment over the QSS solution.
A new picture of life's history on Earth

When most people think of paleontology, they picture the field paleontologist digging up fossils with a toothbrush and publishing descriptions of the anatomies of uncovered specimens in the trade literature. New discoveries of dinosaurs even make the national headlines. For many decades the discovery and description of a previously unknown fossil species was the calling card that gained would-be paleontologists professional acceptance. However, in the last quarter of a century or so, many of the most intriguing new results in paleontology have come not from field studies, but from the compilation and analysis of large-scale databases of fossil species. These databases have provided us with quantitative pictures of the pattern and size of mass extinction events, the rate at which new species have appeared, and crucially the number of species on the planet through time, the so-called standing diversity. In an article appearing in this issue of PNAS (1), John Alroy, Charles Marshall, and a large group of distinguished collaborators report on the creation of a new database that catalogs fossils at the level of individual collections. Preliminary analysis of this database reveals interesting results, calling into question some fundamental ideas about the history of life on Earth. John Alroy, Charles Marshall, and a large group of distinguished collaborators report on the creation of a new database that catalogs fossils at the level of individual collections.
Case report 364

This 46-year-old man was referred to hospital because of occasional stiffness and pain in the right thumb for two years. His symptoms worsened during the past six months. Physical examination demonstrated swelling of the thumb, particularly around the first metacarpophalangeal joint, but no tenderness, redness or local heat was present. Limited flexion of the thumb was noted and a hard mass was palpated in the region of the first metacarpophalangeal joint. Laboratory studies were within normal limits. Roentgenograms of the thumb showed amorphous soft tissue calcifications around the metacarpophalangeal joint (Fig. 1 A), which in a period of a little over two years progressed markedly in size and extent (Fig. 1 B). The articular surfaces and bony structures were intact. One month prior to referral to hospital the patient had undergone a biopsy of the area of the first metacarpophalangeal joint. In the period following the biopsy the mass continued to grow in size. Pressure on the digital nerve resulted in loss of sensation over the ulnar aspect of the thumb. Several flare-ups had occurred, consisting of swelling, pain, erythema, tenderness and localized heat of the metacarpophalangeal joint of the thumb. These episodes subsided in two to three days following treatment with indocin. Based on the results of the biopsy and because of the continued growth of the mass, surgery was performed in an attempt to excise the entire mass around the metacarpophalangeal joint.
Influence of prepartum antibiotic therapy on intramammary infections in primigravid heifers during early lactation.

Jersey heifers were assigned alternately to three groups: 1) negative control (n = 41), 2) intramammary infusion of 200 mg of sodium cloxacillin (n = 38) at 7 d before expected parturition, and 3) intramammary infusion of 200 mg of cephapirin sodium (n = 36) at 7 d before expected parturition. The percentage of mammary glands infected prior to treatment was 62.2, 50.0, and 70.1 for groups 1, 2, and 3, respectively. The percentage of mammary glands infected during early lactation was 44.5, 8.6, and 2.1 for groups 1, 2, and 3, respectively. Most infections (87.1%) were due to Staphylococcus species other than Staphylococcus aureus. Thirty-six of 460 quarters were infected with major pathogens before treatment, 3 of 22 persisted following antibiotic treatment, and 9 of 14 persisted in the control group. Infusion of sodium cloxacillin resulted in antibiotic residues in 17.4% of samples obtained .5 d postpartum. All samples were negative at 3 and 10 d postpartum. Infusion of cephapirin sodium resulted in antibiotic residues in 84.7, 28.2, and 0% of samples obtained at .5, 3, and 10 d, respectively. Prepartum antibiotic therapy was effective in eliminating many IMI, especially those caused by coagulase-negative staphylococci, but there is the potential for antibiotic residues in milk.
Prosimians' manipulation of simple object problems

Abstract Eight problems in manipulation of baited and unbaited objects were given to Tupaia, glis, Galago senegalensis, G. crassicaudatus, Loris tardigradus, Perodicticus potto, Lemur fulvus and L. catta. Loris and G. senegalensis have long bouts of attention and much dependance on hand and eye. They orient rather than manipulate, with little or no manipulation of unbaited objects or objects where the reward is not visible. Tupaia and Lemur have short bouts of attention, relatively great dependance on nose and mouth, and much manipulation of unbaited objects. Perodicticus and G. crassicaudatus are intermediate. The animals' approach to objects is the same as their approach to food. Their understanding of unfamiliar objects is clearly below that of higher primates. Prosimians which depend more on hand and eye are not the most intelligent, but the most narrowly specialized. A tendency to manipulative play at the prosimian level may have preceded advance to simian intelligence.
Design of Resonant Soft-Switching Grid-Connected Inverter

This paper discusses the topology requirements of the small power photovoltaic grid-connected inverter,and introduces several typical topologies,moreover,points out the advantages and disadvantages,efficiency and applicable occasions of the various topologies. In this paper,a single-phase full-bridge grid-connected inverter topology(DC/AC) is designed. The soft-switching technology is employed on the topology for reducing switching loss. The topology can realizes zero voltage switching when the main switch turns on and turns off and zero current switching when auxiliary switch and the power diode turns on and turns off.The converter has higher efficiency than other topologies.
A Vineyard Agroecosystem: Disturbance and Precipitation Affect Soil Respiration under Mediterranean Conditions

We investigated impacts of agricultural management practices on soil respiration (R s ) in a Cabernet Sauvignon (Vitis vinifera) vineyard (Oakville, CA; November 2003-December 2005). We determined (i) response of R s to cover cropping, mowing and tillage; (ii) environmental factors controlling R s ; and (iii) total annual C lost through R s . A winter cover crop was either mown (CC+mow), or mown and tilled (CC+Till), and resident vegetation was tilled (RV+Till). Precipitation amount and pattern differed between years, and low R s rates occurred during summer drought and high rates during wet periods. Total CO 2 emissions differed only in Year 2 (RV+Till: 10.99 ± 0.30, CC+Till: 10.11 ± 0.49, CC+mow: 8.57 ± 0.54 Mg CO 2 - C ha -1 ). After tillage or mowing, R s increased five- to six-fold in tilled treatments and two-fold in the mown treatment (Year 1). In Year 2, R s increased two-to three-fold after tillage only. R s increased after 'post-management' rainfall in spring and was 1.5- to 2-fold greater in tilled than mown treatments in both years due to prior incorporation of plant biomass during tillage. After fall rainfall, R s was 1.7-fold greater in mown than tilled treatments (Year 1). Our findings suggest that the interaction of management practice with climate and soil conditions before disturbance (i.e., management and rainfall) influenced R s . Polynomial regressions of R s on GWC and soil temperature indicated that R s increased until gravimetric water content (GWC) reached 14 to 15% in tilled treatments and 20% in the mown treatment, subsequently declining, indicating thresholds of GWC at which soil temperature more strongly influences R s .
Identifying Potential Pollutant Point Sources in an Area of High Ground Water Consumption

The Commonwealth of Pennsylvania relies heavily upon its ground water resources for drinking water. The U.S. Environmental Protection Agency, Region III, is responsible for regulating the discharge of waste to the subsurface through injection wells within Pennsylvania. To facilitate identification of industrial facilities unregulated by EPA that may be contaminating ground water through industrial water and waste water discharge wells, a screening procedure was devised utilizing a Geographic Information System (GIS). This procedure involved cross-referencing locations of industrial sites to maps of municipal sewer systems. The effectiveness of this GIS screening procedure was investigated in seven counties in southeastern Pennsylvania. Facilities identified by the procedure were inspected for possible violations of Underground Injection Control (UIC) program regulations. As a result of these inspections, many facilities were found to be illegally discharging waste into ground water. In addition, other EPA program violations were identified. The project demonstrated that the GIS screening procedure can be an effective tool to locate sources of pollution of ground water.
High-speed scanning optical coherence tomography

In biomedical imaging high speed axial scanning is very important for obtaining the cross-sectional images of tissue microstructures. For this purpose our optical coherence tomography (OCT) system incorporated a scanning optical delay line (RSOD) that uses Fourier-transform pulse shaping technique. In this technique axial scanning in the time domain is implemented by a linear phase ramp in the frequency domain. By combining the axial scanning (Z-axis) in the reference arm and lateral scanning (X-axis) in the sample arm using a lateral scanning galvanometer, the system could image samples with a size of 400×800 pixels (Z-X image) at the speed of 6 frames per second. Some imaging results are presented in this paper.
Personality Traits in Martial Artists: A Descriptive Approach:

This paper reviews the findings of four studies of selected personality traits of martial artists. Item analysis was used for descriptive purposes and applied to responses to the Buss-Durkee Hostiliry Inventory used in one of them. This yielded suspicion as an active factor for 152 karate students. Groups at intermediate ranks showed a greater variety of hostile modes of expression than either beginner or advanced groups. Assault items were not popular in the group as a whole. Evidence supports both cathartic and circular theories of aggression. Internal validity of scales was determined. The implications of the findings are discussed and the possible contributing influence of physical activity, meditation, and self-defense are considered.
Glucocorticoid Resistance and Hypersensitivity

This article emphasizes the disorders caused by mutations and polymorphisms of the alpha form of the glucocorticoid receptor. These disorders usually present with increased circulating cortisol concentrations and must be distinguished from Cushing's syndrome, because the therapies are markedly different. The other disorders present with clinical features limited to a specific organ system. Although they illustrate important physiologic and pathophysiologic principles, they usually are not confused with Cushing's syndrome.
Effects of Mechanical Forces on Lung-Specific Gene Expression

Fetal breathing movements (FBM) are necessary for fetal lung growth and maturation. The authors analyzed fetal rat lungs cultured with or without lung distension and tracheal ligation, and examined the effects of mechanical stretch on a human pulmonary epithelial cell line (NCI-H441) that shows regulated expression of surfactant proteins (SP-A, SP-B). Cells were grown on silastic membranes and mounted in a Flexercell Strain Unit. Cyclic deformation simulating FBM was achieved by applying a vacuum of 22 kPa (5%-15% radial deformation) at 50 cycles per minute for 2 to 24 hours. Results indicate that static distension for as little as 4 hours decreased steady-state SP-A and SP-B mRNA levels in whole lung (n = 5-6, P < .01). In contrast, cyclic stretching of H441 cells for 24 hours increased SP-B and SP-A expression 2- to 4-fold over controls. Cyclic deformation also significantly enhanced 3H-choline incorporation into saturated phosphatidylcholine. Dynamic mechanodeformation may be a critical stimulus for fetal lung development.
A specific immunoprecipitation assay for the protein kinase FA/glycogen synthase kinase 3.

Abstract A specific immunoprecipitation assay has been developed for the accurate determination of the kinase F A /GSK 3 activity in crude cell preparations. The assay is based on the production and isolation of polyclonal peptide antibodies toward the C-terminus of the rat GSK 3 -α and GSK 3 -β isoforms. The respective forms of the kinases are captured as active immunocomplexes with immobilized secondary antibodies and their kinase activity toward the synthetic peptide P-GS1 can be accurately measured. Immunoprecipitation with a mixture of the two peptide antibodies allows for the detection and estimation of the total kinase F A /GSK 3 activity in cellular extracts, whereas the α-peptide antibody specifically detects and measures the GSK 3 -α isoform. The contribution of GSK 3 -β in the total kinase F A /GSK 3 activity of cell fractions can be calculated.
Nutrition and Multifetal Pregnancy

Largely because of assisted reproduction, the rate of multifetal pregnancy is rising rapidly in the United States. Accordingly, dietitians are increasingly being called upon to provide nutrition services for these high-risk pregnancies. This article gives an overview of the incidence of and risks associated with multifetal pregnancy and reviews studies that contribute to our knowledge of nutrition and multifetal pregnancy. Practice guidelines for promoting healthy outcomes based on the best available scientific data are suggested. Guidelines for weight gain for twin and triplet pregnancy, dietary intake, and supplement use are included. Suggested practice guidelines for multifetal pregnancy include a positive rate of weight gain early in pregnancy, the use of prepregnancy weight status to determine total weight gain goals in twin pregnancy, a 50-lb weight gain goal for triplet pregnancy, and higher minimal number of servings of foods from several of the Food Guide Pyramid groups. The need for additional information on the effects of nutritional status on the course and outcome of multifetal pregnancy is critical. Preliminary evidence of the benefits of nutrition services suggests that both the incorporation of dietetics services into care programs and additional research on nutrition and multifetal gestation are warranted.
Analysis of Pulsatile Hormone Concentration Profiles with Nonconstant Basal Concentration: A Bayesian Approach

Many challenges arise in the analysis of pulsatile, or episodic, hormone concentration time series data. Among these challenges is the determination of the number and location of pulsatile events and the discrimination of events from noise. Analyses of these data are typically performed in two stages. In the first stage, the number and approximate location of the pulses are determined. In the second stage, a model (typically a deconvolution model) is fit to the data conditional on the number of pulses. Any error made in the first stage is carried over to the second stage. Furthermore, current methods, except two, assume that the underlying basal concentration is constant. We present a fully Bayesian deconvolution model that simultaneously estimates the number of secretion episodes, as well as their locations, and a nonconstant basal concentration. This model obviates the need to determine the number of events a priori. Furthermore, we estimate probabilities for all "candidate" event locations. We demonstrate our method on a real data set.
Reaction of silicon ion (2P) with silane (SiH4, SiD4). Heats of formation of SiHn, SiHn+ (n = 1, 2, 3), and Si2Hn+ (n = 0, 1, 2, 3). Remarkable isotope exchange reaction involving four-hydrogen shifts

The reaction of ground-state silicon ion with silane is investigated by using a guided ion beam tandem mass spectrometer. Reaction cross sections of all possible fragments, Si/sub m/H/sub n//sup +/ (m = 1, 2; n = 0, 1, 2, 3), as a function of relative kinetic energy are determined. All thermal energies, the major product is Si/sub 2/H/sub 2//sup +/. One remarkable reaction, the interchange of the projectile silicon ion with the target silicon atom, is observed at near zero kinetic energy. Labeling experiments employing /sup 30/Si/sup +/ for the beam or SiD/sub 4/ for the reactant indicate the intermediacy of the disilicon hydrides for the formation of the observed products. From the endothermicities of several reactions, the 298 K heats of formation for several ionic and neutral silicon hydrides are derived: ..delta..H/sub f//sup 0/(SiH) = 90.0 +/- 1.7, ..delta..H/sub f//sup 0/(SiH/sub 2/) = 69.0 +/- 2, ..delta..H/sub f//sup 0/(SiH/sub 3/) = 48.5 +/- 1.6, ..delta..H/sub f//sup 0/(SiH/sub 2//sup +/) = 276.1 +/- 1.7, ..delta..H/sub f//sup 0/(SiH/sub 3//sup +/) = 237.1 +/- 2, ..delta..H/sub f//sup 0/(Si/sub 2//sup +/) less than or equal to 328.0 +/- 2, ..delta..H/sub f//sup 0/(Si/sub 2/H/sup +/) less than or equal to 304.4 +/- 1.6, ..delta..H/submore » f//sup 0/(Si/sub 2/H/sub 2/) less than or equal to 268.0 +/- 2.6, ..delta..H/sub f//sup 0/(Si/sub 2/H/sub 3//sup +/) = 266 +/- 2, all in kcal/mol. From an evaluation of these and other experiments, values of ..delta..H/sub f//sup 0/(SiH/sub 2//sup +/) and ..delta..H/sub f//sup 0/(SiH/sub 2/) of 278.0 +/- 1.4 and 68.5 +/- 1.5 kcal/mol, respectively, are recommended.« less
Health related quality of life in patients treated with multimodal therapy for prostate cancer.

Purpose: Patients with prostate cancer and high risk disease characteristics may benefit from multimodal therapy. However, the effects of multimodal therapy on health related quality of life have not been comprehensively described. We further characterized health related quality of life in patients treated with multimodal therapy.Materials and Methods: Patient data were obtained from the CaPSURE™ database, a national disease registry of men with prostate cancer. Included patients received active primary therapy (ie surgery or various forms of radiation) for prostate cancer with or without adjuvant or neoadjuvant therapy, and had complete clinical data, including health related quality of life assessments at baseline and through 2 years after treatment. The association between health related quality of life outcomes and different primary therapies with and without adjuvant or neoadjuvant therapy over time was analyzed using a repeated measures mixed model for each primary therapy.Results: A total of 2,204 ...
Note on generalized self-organizing network algorithms

In this note we identify some similarities and differences between two clustering models, viz., the fuzzy c-means (FCM) and Kohonen self-organizing (KSO) feature map approaches. This leads us to suggest that there is an important unknown relationship between the two methodologies. Consequently, we propose several avenues of research which, if successfully resolved, will strengthen both the FCM and Kohonen models and their utility for applications in clustering and classifier design.
Generation of T cell receptor-retrogenic mice: improved retroviral-mediated stem cell gene transfer.

The use of retrogenic mice offers a rapid and flexible approach to T cell receptor (TCR)-transgenic mice. By transducing bone marrow progenitor cells with a retrovirus that encodes a given TCR-α/β subunit, TCR-retrogenic mice can be generated in as few as 4–6 weeks, whereas conventional TCR transgenics can take 6 months or longer. In this updated protocol, we have increased the efficiency of the bone marrow transduction and bone marrow reconstitution compared with our previously published protocol. The main departure from the previous protocol is the implementation of spin transduction with the viral supernatant instead of coculture with the viral producer cell line. The changes in this protocol improve bone marrow viability, increase consistency of the bone marrow transduction and bone marrow engraftment, and they reduce the ratio of bone marrow donor mice to bone marrow recipients.
EBNA3A Association with RBP-Jκ Down-Regulates c-myc and Epstein-Barr Virus-Transformed Lymphoblast Growth

Epstein-Barr virus nuclear antigen protein 3A (EBNA3A) is one of four EBNAs (EBNA-2, EBNALP, EBNA3A, and EBNA3C) through the cellular DNA sequence-specific transcription factor RBP-Jκ/CBF-1/CSL and are essential for conversion of primary B lymphocytes to lymphoblastoid cell lines (LCLs). In the present study, we investigated the effects of EBNA3A on EBNA2 activation of transcription in the IB4 LCL by conditionally overexpressing EBNA3A three- to fivefold. EBNA3A overexpression increased EBNA3A association with RBP-Jκ, did not change EBNA3C association with RBP-Jκ or EBNA or LMP1 expression, decreased EBNA2 association with RBP-Jκ, decreased c-myc expression, and caused G0/G1 growth arrest with prolonged viability. Expression of the fusion protein MycERTM in cells with conditional EBNA3A overexpression restored cell cycle progression and caused apoptosis. In contrast, MycER in the same cells without EBNA3A overexpression enhanced cell proliferation and did not increase apoptosis. These data indicate that EBNA3A overexpression inhibits protection from c-myc-induced apoptosis. In assays of EBNA2- and RBP-Jκ-dependent transcription, EBNA3A amino acids 1 to 386 were sufficient for repression equivalent to that by wild-type EBNA3A, amino acids 1 to 124 were unimportant, amino acids 1 to 277 were insufficient, and a triple alanine substitution within the EBNA3A core RBP-Jκ binding domain was a null mutation. In reverse genetic experiments with IB4 LCLs, the effects of conditional EBNA3A overexpression on c-myc expression and proliferation did not require amino acids 524 to 944 but did require amino acids 278 to 524 as well as wild-type sequence in the core RBP-Jκ binding domain. The dependence of EBNA3A effects on the core RBP-Jκ interaction domain and on the more C-terminal amino acids (amino acids 278 to 524) required for efficient RBP-Jκ association strongly implicates RBP-Jκ in c-myc promoter regulation.
A Linear Equivalent Barotropic Model of the Antarctic Circumpolar Current with Realistic Coastlines and Bottom Topography

Abstract A linear equivalent barotropic (EB) model is applied to study the effects of the bottom topography H and baroclinicity on the total transport and the position of the Antarctic Circumpolar Current (ACC). The model is based on the observation of Killworth that the time mean velocity field of the FRAM Model is self-similar in the vertical. A realistic large-scale topography H is constructed by filtering 5-minute resolution data with an appropriate smoothing kernel. It is shown that the asymptotic behavior of the solution of the barotropic model (a particular case of the EB model) in the limit of very small bottom friction depends on subtle details of topography and basin geometry. Given the uncertainties of the smoothing procedure the authors conclude that the barotropic model is not robust with respect to possible variations of model topography. The authors found that the EB model with a vertical profile function similar to that of Killworth reproduces the major features of the time- and depth-ave...
Cultural Perspectives in Participatory Ergonomics

This paper examines the generalizability of participatory ergonomics to different cultures. Studies using participatory strategies to introduce ergonomic solutions are reviewed across three distinct cultures. The results lead us to believe that these effects are sufficiently robust and not culture or method bound. Four lessons can be learned from these participatory interventions: 1) Interventions should build on local customs; 2) Solutions should be practical and understandable to the participating end-users; 3) Culture should be used as a resource for solving design and cross-cultural problems; and 4) Synergy between the culture and the intervention will enhance the success and magnify problems of the intervention.
The behavioral sciences and concepts and standards for management planning and control

Abstract This article reviews behavioral research on the individual, small groups and organizations and the implications of this research for management accounting. Also, opportunities for accounting research are identified and, where appropriate, extant accounting research is discussed. The conclusion is that studies of individual and group behavior are inseparable from studies of complex organizations and vice versa. Furthermore, fundamental research into personal, oragnizational, and environmental variables and their impact on effective management planning and control systems is urgently needed.
Stimulated Brillouin Scattering (SBS) in Small Core Photonic Crystal Fibers (PCF)

SBS is studied in four different photonic crystal fibers with core diameters ranging from 8 mum to 1.7 mum. Of particular interest is the observation of several peaks and their strong polarization dependence in small core PCFs.
Effect of carbon tetrachloride on the metabolism, storage, and excretion of sulfobromophthalein☆

Abstract It is well documented that CCl4 produces morphologic and functional changes in the liver. The abnormal functional effects produced by CCl4 are easily demonstrated by the retention of sulfobromophthalein (BSP). However, since BSP undergoes storage, metabolism, and excretion by the liver, these parameters were examined to determine which process or processes are altered by CCl4. With intraperitoneal administrations of CCl4 no change in hepatic storage was demonstrated, but a significant increase in BSP plasma retention, a decrease in in vitro metabolism, and a decrease in transport maximum were observed. These same parameters were measured with an analog of BSP which is not metabolized, phenol-3,6-dibromophthalein disulfonate (DBSP). CCl4 did not produce a decrease in the hepatic storage of DBSP either, but did depress the plasma disappearance of DBSP, and the transport maximum of DBSP. During infusions of BSP or DBSP at rates below the maximal excretory rate, decreased dye excretion was observed in the CCl4-treated rats. Therefore, it appears that CCl4 exerts an important effect on the excretory parameter of the liver, and perhaps this effect is the one which contributes the most toward plasma BSP retention.
Temporal experience as a function of organization in memory

The relationship between memory organization and perceived duration was investigated in two experiments. Degree of organization of the memory representation for an interval was assumed to be inversely related to the complexity of the interval’s content. Organization was manipulated by presenting an ambiguous stimulus during the interval either with or without the aid of a code that simplified the stimulus. Subjects judged the duration of a 60-sec interval by the method of magnitude estimation and then recalled the interval’s contents. In both experiments, facilitating memory organization by presenting the simplifying code before the interval was found to shorten apparent duration. In the second experiment, presenting the code after the stimulus interval also significantly shortened apparent duration when compared with the “no-code” condition. In general, the results were consistent with Ornstein’s (1969) storage size notion of the experience of duration. Some limitations of the storage size hypothesis are discussed.
PARTICIPATION IN BOYS AND GIRLS CLUBS AND RELATIONSHIPS TO YOUTH OUTCOMES

Participation is a key issue in youth development organizations. In fact, research suggests that youths who attend the programs offered by these agencies will experience numerous benefits. One such youth development organization is the Boys and Girls Clubs of America (BGCA). Much of the research pertaining to the BGCA examines the importance of participation in structured prevention and educational programs such as Project SMART and Project Learn. The everyday Club participant, however, does not necessarily attend these structured programs. As such, the present study was designed to gain a better understanding of “typical” Club participation and how overall attendance at the Club is related to positive outcomes among youth. A total of 139 youths (aged 10 to 18 years old) participated in the study. Overall participation in the Club and age were both independently related to enhanced academic achievement, as well as increased substance use. Additionally, significant age and participation interaction effects point to the importance of Club participation at nullifying risks and problem behaviors associated with increasing age, particularly in relation to academic outcomes. Implications are discussed pertaining to program strategies that may serve as hooks or magnets that sustain youths’ interest and continued involvement in BGCA activities and other youth development programs. © 2003 Wiley Periodicals, Inc.
Using multiset discrimination to solve language processing problems without hashing

It is generally assumed that hashing is essential to solve many language processing problems efficiently; e.g. symbol table formation and maintenance, grammar manipulation, basic block optimization, and global optimization. This paper questions this assumption, and initiates development of an efficient alternative compiler methodology without hashing or sorting. The methodology rests on efficient solutions to the basic problem of detecting duplicate values in a multiset, which we call multiset discrimination. Paige and Tarjan (1987) gave an efficient solution to multiset discrimination for detecting duplicate elements occurring in a multiset of varying length strings. The technique was used to develop an improved algorithm for lexicographic sorting, whose importance stems largely from its use in solving a variety of isomorphism problems (Aho et al., 1974). The current paper and a related paper (Paige, 1994) show that full lexicographic sorting is not needed to solve these isomorphism problems, because they can be solved more efficiently using straightforward extensions to the simpler multiset discrimination technique. By reformulating language processing problems in terms of multiset discrimination, we also show how almost every subtask of compilation can be solved without hashing in worst case running time no worse (and frequently better) than the best previous expected time solution (under the assumption that one hash operation takes unit expected time). Because of their simplicity, our solutions may be of practical as well as theoretical interest. The various applications presented culminate with a new algorithm to solve iterated strength reduction folded with useless code elimination that runs in worst case asymptotic time and auxiliary space Θ(¦L¦ + ¦L'¦), where ¦L¦ and ¦L'¦ represent the lengths of the initial and optimized programs, respectively. The previous best solution due to Cocke and Kennedy (1977) takes Ω(¦L¦3¦L'¦) has operations in the worst case.
IR‐red GaAs‐AlAs superlattice laser monolithically integrated in a yellow‐gap cavity

Disk‐shaped IR‐red (Eg ∼1.61 eV) GaAs‐AlAs superlattice lasers (41 Lz ∼45‐A GaAs layers, 40 LB ∼150‐A AlAs layers) are demonstrated (cw 300 K) that are monolithically integrated into rectangular yellow‐gap AlxGa1−xAs [x∼LB/(Lz+LB), EgX∼2.08 eV] cavities. The yellow‐gap AlxGa1−xAs (x∼0.77) is generated by low‐temperature Zn diffusion (575 °C, 30 min), which disorders selected portions of the superlattice [portions complementary to regions (disks) masked by Si3N4].
Quasi-energy spectrum of multiband superlattices in dc-ac electric fields

The dynamics of Bloch electrons moving in a two-band superlattice driven by a dc-ac electric field is investigated. We show rigorously that (i) when the matching ratio between the Bloch frequency and the ac frequency is an integer, the spectrum is that of two quasi-energy bands; (ii) when the matching ratio is a rational, the spectrum is two interspaced fractional Wannier-Stark ladders; and (iii) each of these fractional ladders has an energy dispersion due to the interband coupling. We illustrate our findings by explicit calculations of the spectrum in the high-frequency case, and show how the energy dispersion is tuned by the ac field strength and how band collapse occurs.
Partial oxidation of CH4 and C2H6 over noble metalcoated monoliths

Abstract The direct partial oxidation of hydrocarbons offers promising alternatives to chemical synthesis. By replacing endothermic processes such as steam reforming and steam cracking, fast and exothermic oxidation reactions should require much smaller and simpler reactors. However, direct oxidation reactions are much more difficult to manage because of potential heat release in total oxidation and hazardous because of the possibility of homogeneous reactions which are nonselective and can produce flames and explosions. We describe experiments in which monolith catalysts are used for partial oxidation of CH4 and C2H6 to produce synthesis gas or alkenes by direct oxidation at or above atmospheric pressure in pure O2 in nearly adiabatic reactors operating at 1000°C with very high flowrates (space velocities of 106h−1 and residence times of 10−3 s). With methane oxidation we obtain over 90% selectivities to synthesis gas (a 2:1 H2:CO mixture) with > 90% conversion of the methane and complete conversion of O2 on Rh coated ceramic monoliths with contact times of 10−3 s. With Pt catalysts under the same conditions, the H2 selectivity drops to 70%; while with Pd, the catalyst rapidly forms carbon. This process appears to be primarily a surface reaction in which CH4 pyrolyzes on the hot Rh surface and the H atoms dimerize and the carbon is oxidized to CO. A model has been constructed which accurately predicts the conversions and selectivities and the variations between Rh and Pt. With higher alkanes, synthesis gas is produced on Rh with comparable selectivities and conversions on metal-coated monoliths. However, with Pt we observe up to 70% selectivity to alkenes with 80% conversion of alkanes at adiabatic temperatures near 1000°C with approximately 5 ms contact times. These results can be explained as occurring by predominantly surface reactions in which the alkane adsorbs to form the alkyl by H abstraction with adsorbed O atoms. Then the adsorbed alkyls undergo primarily β-elimination reactions on Pt to produce alkenes. These products are therefore far from thermodynamic equilibrium at these very short contact times, even though the temperatures are very high. The use of very short contact times and high temperatures promises to provide new routes to production of partial oxidation products with very small adiabatic reactors and thus opens up new types of reactions and reactors for chemical synthesis.
Simulations of glass surfaces-structure, water adsorption, and bond rupture

Molecular dynamics simulations of the structure of silica glass surfaces formed in a perfect vacuum as well as in the presence of a water vapor show the type, location, and concentration of specific features formed in the surface. A bond rupture mechanism which causes silanol formation far removed from the original reaction site is observed. The 3-membered ring is proposed as a site for H adsorption in the glass.
The serpent and the sparrows: Homer and the parodos of Aeschylus’ Agamemnon

The Homeric influence on two prominent avian images in the parodos of the Agamemnon—the vulture simile (49–50) and the omen of the eagles and the pregnant hare (109–10)—has long been noted. In 1979 West suggested that the animal imagery also derived in part from Archilochus’ fable of the fox and the eagle (frr. 172–81 West), and his discussion was quickly welcomed and supplemented by Janko's reading of the eagle and snake imagery used by Orestes at Cho. 246–7. Capping this triennium mirabile of critical interest in Aeschylus’ birds of prey, Davies argued that the convincing resemblances between the fable and the Aeschylean passages in West's thesis—the anthropomorphism implied in παίδων (Ag. 50) and δeγπνον (Ag. 137) and the concern of Zeus for aggrieved animals (Ag. 55–6)—derive more generally from the nature of fable rather than from any one particular tale. Thus we have, according to Davies, an example of Aeschylus ‘exploring the resources and familiar modes of expression of a popular and well-known genre’ and transforming it into ‘the purest and sublimest type of poetry’.
Raider tracer: a MATLAB-based electromagnetic scattering simulator

Computational methods for electromagnetic scattering prediction have been an invaluable tool to the radar signal exploitation community. Scattering prediction codes can provide simulated data of varied levels of fidelity at a fraction of the cost of measured data. Software based on physical optics theory is presently the tool of choice for generating high-frequency scattering data. Currently available codes have extensive capabilities but are usually restricted in their distribution or application due to government or proprietary concerns and due to platform specific software designs. The Raider Tracer software, described in this paper, is a MATLAB-based scattering prediction code that was developed for open distribution to the broader research community.
The thermal analysis study of the drug captopril

Abstract Captopril is an antihypertensive drug currently being administered in tablet form. The thermal analysis study was carried out using a simultaneous TG–DTA unit. Both the isothermal and non-isothermal experiments are preformed to investigate the thermal degradation process of captopril in its natural state as a solid. The runs were performed in a flowing nitrogen atmosphere. Captopril melted at 106°C followed by decomposition. Based on the order of reaction, one method is used to identify the reaction mechanism in isothermal kinetics and two methods are used to identify the reaction mechanism in non-isothermal kinetics. These methods use the equations established by Avrami–Erofeev, Arrhenius and Freeman and Carroll. However, a kinetic analysis based on the “method of fit” using zero-order, first-order, and second-order equations showed that a first-order process gave a good fit for the Arrhenius plot at certain specific experimental conditions (i.e. very low sample mass). Overall, a second-order process followed by a first-order reaction for the main decomposition process of captopril showed an even better fit for the experiments. The possible reasons for this kinetic behavior are presented. There was up to 2% carbon remaining at 500°C. Thermal analysis was supplemented using Fourier Transform infrared spectroscopy (FTIR), X-ray diffraction and scanning electron microscopy (SEM) methods to identify the captopril with any degradation products which may have formed.
AURA: a programming language for authorization and audit

This paper presents AURA, a programming language for access control that treats ordinary programming constructs (e.g., integers and recursive functions) and authorization logic constructs (e.g., principals and access control policies) in a uniform way. AURA is based on polymorphic DCC and uses dependent types to permit assertions that refer directly to AURA values while keeping computation out of the assertion level to ensure tractability. The main technical results of this paper include fully mechanically verified proofs of the decidability and soundness for AURA's type system, and a prototype typechecker and interpreter.
Atypical polyagglutination associated with an acquired B antigen.

The finding of an acquired B antigen, together with plyagglutination, in an elderly man led to studies indicating adsorption of bacterial material as the likely cause of both of these red blood cell anomalies. The various causes of plyagglutination are durcussed. Based upon the differendal characteristia of each type, a classification of ply agglutination is proposed. POLYACCLUTINATION denotes the agglutination of red blood cells by most normal adult sera, but not by the sera of newborn infants. This abnormality has been noted most frequently in association with either bacterial contamination in uitro or bacterial infection in vivo. When observed in vivo, the phenomenon usually is temporary, although occasionally it has persisted for months25 or even for several years.14 Red blood cells treated with neuraminidase provide a model of polyagglutination. This enzyme splits N-acetyl-neuraminic acid from sialo-mucoproteins16 exposing structures capable of reacting with the antiT agglutinin of normal serum, and this, or a very similar mechanism, probably is responsible for most cases of T-activation in vivo. In addition, the polyagglutinable state in vivo occasionally results from causes other than classical T-activation, a condition termed “atypical” polyagglutinaThis report describes a further case of atypical polyagglutination; however, in this instance it is associated with an acquired B antigen. tion.5, 9. 13. 14. 16
Variance estimation using replicated batch means

We present a new method for obtaining confidence intervals in steady-state simulation. In our replicated batch means method, we perform a small number of independent replications to estimate the steady-state mean of the underlying stochastic process. In order to obtain a variance estimator, we further group the observations from these replications into nonoverlapping batches. We show that for large sample sizes, the new variance estimator is less biased than the batch means variance estimator, the variances of the two variance estimators are approximately equal, and the new steady-state mean estimator has a smaller variance than the batch means estimator when there is positive serial correlation between the observations. For small sample sizes, we compare our replicated batch means method with the (standard) batch means and multiple replications methods empirically, and show that the best overall coverage of confidence intervals is obtained by the replicated batch means method with a small number of replications.
Wafer Test Methods to Improve Semiconductor Die Reliability

Incremental advances in semiconductor device testing have improved device quality and reliability. New test methods applied to dies at the wafer level are now significantly improving the reliability of devices sold to the increasing bare-die market and reducing burn-in requirements for packaged devices.
SPARK: a high-level synthesis framework for applying parallelizing compiler transformations

This paper presents a modular and extensible high-level synthesis research system, called SPARK, that takes a behavioral description in ANSI-C as input and produces synthesizable register-transfer level VHDL. SPARK uses parallelizing compiler technology, developed previously, to enhance instruction-level parallelism and re-instruments it for high-level synthesis by incorporating ideas of mutual exclusivity of operations, resource sharing and hardware cost models. In this paper, we present the design flow through the SPARK system, a set of transformations that include speculative code motions and dynamic transformations and show how these transformations and other optimizing synthesis and compiler techniques are employed by a scheduling heuristic. Experiments are performed on two moderately complex industrial applications, namely MPEG-1 and the GIMP image processing tool. The results show that the various code transformations lead to up to 70 % improvements in performance without any increase in the overall area and critical path of the final synthesized design.
Nitric oxide-mediated renal epithelial cell injury during hypoxia and reoxygenation

The potent endothelial-derived vasodilator nitric oxide (NO) has been identified as a protective agent in acute renal failure. However, some recent studies have suggested a detrimental effect of NO on rat proximal tubules exposed to hypoxia and reoxygenation. We determined whether NO metabolites cause intracellular oxidation during hypoxia and reoxygenation and whether this oxidative stress is linked to irreversible cell injury. Primary cultures of rat proximal tubular epithelial cells were studied in a subconfluent stage and subjected to 60 min hypoxia and 30 min reoxygenation. Intracellular oxidation was assessed by monitoring the conversion of nonfluorescent dihydrorhodamine 123 (DHR) to fluorescent rhodamine 123 as a probe for the long-lived oxidant peroxynitrite. Hypoxia and reoxygenation produced a marked increase in cellular generation of oxidant species. Intracellular oxidation of DHR was reduced by approximately 40% when cells were also exposed to the NO synthase inhibitor L-NAME. Oxidation of DHR following hypoxia and reoxygenation was not affected by SOD or DMTU. A combination of SOD and L-NAME was no more effective than L-NAME alone. Hypoxia and reoxygenation produced substantial injury (as LDH release). There was a 40% reduction in LDH release when cells were pretreated with a NO synthase inhibitor. In summary, increased generation of NO capable of inducing intracellular oxidizing reactions and cell death occurred during renal hypoxia and reoxygenation.
Theorizing Teacher Agency and Reform: How Institutionalized Instructional Practices Change and Persist.

One reason reform does not dramatically change public schools is because instructional practices are highly institutionalized. This article advances a theory for how teacher agency can both change and maintain institutionalized instructional practices in schools. Based on findings from one U.S. urban public school undergoing state-mandated reform, I assert that three mechanisms drive a particular form of teacher agency. Whether these three mechanisms change or maintain institutionalized instructional practices depends on a set of counterbalancing forces that determine how much innovation versus socialization exists in peer learning; how much cohesion versus diversity is involved in community interactions; and how much cognitive and normative divergence versus convergence characterizes teachers’ shared understandings, aims, and practices. The theory provides a generalizable framework for the activities that help teachers drive outcomes in their schools and for the cognitive and social conditions that may b...