cssi/SciSciGPT-SciSciNet huggingface dataset:
Approximate optimal control of nonlinear systems with quadratic performance criteria

A method is presented that approximates the solution to a nonlinear optimal control problem with quadratic cost function.We assume that the nonlinear system is accurately represented by a high-fidelity (hf) model which can be of high complexity or even of “black-box” type. The hf-model is oftentimes unsuitable for solving the optimal control problem. The proposed solution method is based on an Iterative Model and Trajectory Refinement (IMTR) strategy that uses a low-fidelity (lf) model to solve the optimal control problem. The lf-model is obtained through linearization of the hf-model, where the linearization point is variable by the optimization algorithm. The method is demonstrated for two problems of orbital transfer and of underactuated spacecraft attitude control with two reaction wheels. In both examples the solutions are shown to be in good agreement with the optimal solutions obtained by solving the respective nonlinear two-point-boundary value problem.
Characterization and chromosomal localization of the cornea-specific murine keratin gene Krt1.12.

Keratins are a group of water-insoluble proteins constituting paired acidic and basic keratin molecules that form 10-nm intermediate filaments in epithelial cells. Expression of the K3/K12 keratin pair characterizes the cornea-type differentiation. However, the mechanism that regulates this cornea-specific K12 expression remains unknown. To provide a better understanding of the cornea-specific expression, we have cloned the K12 cDNA (Liu, C.-Y., Zhu, G., Westerhausen-Larson, A., Converse, R., Kao, C. W.-C., Sun, T.-T., and Kao, W. W.-Y. (1993) Curr. Eye Res. 12, 963-974). In present studies, the murine K12 keratin gene (Krt1.12) was isolated and characterized. The murine Krt1.12 gene spans 6,567 base pairs of genomic DNA, and the mRNA encoding K12 keratin is distributed into eight exons. Chromosome mapping reveals that murine Krt1.12 is located within the Krt1 complex of mouse chromosome 11. In addition to the production of authentic K12 mRNA, the Krt1.12 gene gives rise to several alternate poly(A)+ RNAs by the use of alternative splicing in intron 2, an alternative promoter in intron 1, and/or both. Sequence analysis indicates that the transcripts derived from alternative splicing and/or the alternative promoter do not have a long open reading frame for keratin or keratin-like molecules. It is not known whether these alternate K12 poly(A)+ RNAs have any biological functions, e.g. regulation of K12 gene expression.
Lasing and mode switching in circular Bragg nanoresonators

We demonstrate low-threshold lasing at telecommunications wavelengths from high quality circular semiconductor nanoresonators employing radial Bragg reflector single-mode emission and mode switching are observed at room temperature under optical pumping.
Examining Absorptive Capacity in Supply Chains: Linking Responsive Strategy and Firm Performance

Information management is a core supply chain activity that is increasing in importance as firms strive to become more responsive to growing customer demand for innovative products. However, effective processing of information from customers and suppliers remains a struggle for most firms. Absorptive capacity provides a useful view of information processing activities, but the current understanding of how firms use it to improve performance and why some firms seem to develop it while others do not remains unclear. This study is grounded in information processing theory, and examines the role of absorptive capacity in linking a firm's responsive strategy and performance. We test a structural equation model on data from 711 manufacturing firms, and validate our results on a second sample of 677 firms. Our study makes three major contributions by providing evidence that: (1) absorptive capacity is motivated by a firm's responsive strategy; (2) it fully mediates the relationship between responsive strategy and firm performance, indicating that absorptive capacity is a necessary competence for firms that aim to deliver innovative products to customers; and (3) the relationship between responsive strategy and absorptive capacity is U-shaped, indicating that when firms attempt to blend efficient and responsive strategies, their ability to develop absorptive capacity is diminished
Characterization of replicative intermediate RNA of mouse hepatitis virus: presence of leader RNA sequences on nascent chains.

Abstract Mouse hepatitis virus A59 codes for seven mRNAs in infected cells. These mRNAs are transcribed from a minus (-) strand template of genome length and contain a leader RNA at their 5' ends. To further elucidate the mechanism of coronavirus transcription, we examined the structure of mouse hepatitis virus replicative intermediates (RIs) isolated by 2 M NaCl precipitation and Sepharose 2-B column chromatography. Purified RIs migrated as a single species on agarose gels and sedimented between 12 and 38S on 10 to 25% sucrose gradients. The complexes were readily heat denatured into a heterogeneous population of smaller RNA molecules which probably represent nascent plus (+) strands. RNase A digestion of RIs produced a single replicative form which sedimented between 30 and 32S. These data suggest that the RI is composed of a single genome-sized (-) strand hydrogen bonded to an average of 4 to 6.5 nascent (+) strands. In contrast, a column-purified replicative form was extremely resistant to RNase A digestion and heat denaturation and migrated as a single RNA species on agarose gels and sucrose gradients. Oligonucleotide fingerprinting of an RI revealed the presence of the 5' leader RNA on the nascent (+) strands. In addition, an average of 6.2 cap structures were present in each RI, which agrees with the average number of nascent (+) strands per RI. These data suggest that the leader RNA is utilized as a primer for mouse hepatitis virus RNA transcription and is not added to mRNA post-transcriptionally.
Adaptive nonlinear contour coupling control for a machine tool system

The quality of products from a machine tool system is largely determined by the tolerances maintained, which is a function of how well the desired contour is tracked. To mitigate contour errors in a three axis machine tool feed drive system, the control development in this paper is based on an error system that is transformed into tangential, normal and binormal components to the desired contour (i.e., a cross coupling controller (CCC)). Unlike previous CCCs, the first controller in this paper does not assume exact knowledge of the inertia and friction matrices. Specifically, an adaptive estimate is developed to compensate for uncertain friction and inertial parameters. Lyapunov-based methods are used to craft the adaptive estimate and to prove global asymptotic contour tracking. A second controller is developed for machine tool dynamics that include unknown friction forces and uncertain cutting force disturbances. The second controller is crafted using an integral signum feedback compensation term that yields semi-global asymptotic contour tracking
Domain decomposition by iterative field bouncing

In modeling geometries that involve two or more distinct partitions, an iterative field bouncing (IFB) method can be applied to substantially reduce total memory requirements. This approach also makes possible the use of several different techniques simultaneously, where the optimal analysis method can be chosen for each partition. Application of IFB accelerates solutions particularly in situations where each partition is moving with a velocity independent of the others. Results are shown for a typical application of IFB.
Reward and punishment: Patterns in Arab and Jewish school children

Abstract To test conflicting hypotheses regarding differences between Christian Arabs, Moslem Arabs, and Jews in reported critical incidents of reward and punishment. 1,440 children, grades 2–12 from Israel and the West Bank, were interviewed on critical incidents of reward and punishment. The groups in Israel represented: Christians, Moslems, non-Orthodox Jews, and Orthodox Jews; on the West Bank: Christians and Moslems. Results show support for Dennis in that the Arab groups were homogeneous and reflected traditional Arab values and strong family orientation. The Jewish groups, while also relatively homogeneous, were significantly different from the Arab groups and reflected values more away from the family and toward the pattern shown by American children.
Australite (meteoric) glass

Typical specimens of Australite (tektite) glass have been studied for such properties as expansivity, annealing temperature, chemical durability over an extended pH range, hygroscopicity, electrode pH response, heterogeneous equilibria at the liquid-solid interface, and spectral transmittance to ultraviolet, visible, and infrared radiations. The results obtained on this glass, supposedly of extra-terrestrial origin, have been compared with similar data obtained on obsidian glass, from Yellowstone Park, and some present-day industrial, optical, and natural glasses. The comparison showed the Australite specimens to be distinctly different from the obsidian, the optical glasses, and the industrial glasses. High softening temperature (approximately 175°C higher than Pyrex 7740), intermediate expansivity, good chemical durability, and low electrode pH response showed the Australite glass to be generally superior. The spectral transmittance was inhibited throughout the ultra violet, visible, and infrared regions by the presence of coloring oxides such as iron, chromium, copper, nickel, and manganese.
Action and attentional load can influence aperture effects on motion perception.

When a moving featureless contour is viewed through a stationary circular aperture that occludes the contour’s endpoints and the contour moves in a direction non-parallel to its orientation, observers report the contour’s direction of motion as perpendicular to the contour’s orientation regardless of its actual direction. In typical studies of this aperture effect on motion perception, observers made perceptual judgments of the line’s motion. The aperture effect was not measured when observers actively controlled the line’s motion. In addition, effects of attentional load on the aperture effect were not measured. Here, we demonstrated that attentional load influenced the aperture effect. Active control reduced the aperture effect, but did not eliminate it. Results have theoretical implications for motion perception and practical implications for the design of technologies that limit an observer’s field-of-view such as surgical cameras.
Potassium and caffeine contractures of mouse muscles before and after fatiguing stimulation.

To assess the impairment of muscle membrane excitation, excitation–contraction (E–C) coupling, and contractility during muscle fatigue, we monitored the contracture responses of resting and fatigued muscles on exposure to high potassium and caffeine. On exposure to 140 mmol/L potassium, mouse extensor digitorum longus (EDL) developed a contracture which was 15.7% of tetanic tension before fatigue and 31.7% after fatigue, while soleus developed 59.4% contracture before and 68.8% after fatigue. Potassium causes contractures by depolarizing the muscle fiber membrane. Hence, membrane excitation is reduced in fatigued EDL and soleus. On exposure to 32 mmol/L caffeine, the contracture was 7.1% in resting EDL, 8.5% in fatigued EDL, 50.1% in resting soleus, and 43.7% in fatigued soleus. On exposure to 1 mmol/L caffeine followed by rapid cooling, the contracture was 3.0% in resting EDL, 3.2% in fatigued EDL, 21.5% in resting soleus, and 10.3% in fatigued soleus. Caffeine causes contracture by releasing Ca+ + from the sarcoplasmic reticulum. Our results indicate reduced E–C coupling attributable to reduced membrane excitation in fatigued EDL, and reduced contractility in fatigued soleus. © 1994 John Wiley & Sons, Inc.
Effects of smoking cues and argument strength of antismoking advertisements on former smokers' self-efficacy, attitude, and intention to refrain from smoking.

INTRODUCTION This study examines the impact of smoking cues employed in antismoking advertisements on former smokers. Previous findings indicate that visual smoking cues in antismoking advertisements with weak antismoking arguments can elicit smoking urges in smokers and undermine message effectiveness. This study extends these observations to former smokers asking whether smoking cues in antismoking advertisements influence former smokers' self-efficacy, attitudes, and intention to refrain from smoking, along with smoking urges and perceived message effectiveness. METHODS The study was a mixed 2 (smoking cues; present vs. absent) × 2 (argument strength [AS]; high vs. low) design where smoking cue was a between-subject factor and AS was a within-subject factor. Potential participants recruited via online ads were screened in a phone interview for their eligibility. A total of 105 former smokers (aged 21-65) participated in the study, which was conducted in a laboratory setting. Repeated measure ANOVA and MANOVA were used for the analyses. RESULTS The results showed that the presence of smoking cues in antismoking ads undermines former smokers' behavioral self-efficacy, attitude, and intention about smoking abstinence, which increased as AS for the ads increased. Former smokers' reports of smoking urge were not affected by smoking cues or AS. However, consistent with previous findings for smokers, the presence of cues weakened perceived message effectiveness of antismoking ads rated by former smokers. CONCLUSIONS The effect of smoking cues on former smokers' self-efficacy, attitude, and intention to refrain from smoking is problematic. Inclusion of smoking cues in antismoking ads should be undertaken only when accompanied by strong arguments.
Translocation of activator of G-protein signaling 3 to the Golgi apparatus in response to receptor activation and its effect on the trans-Golgi network.

Abstract Group II activators of G-protein signaling play diverse functional roles through their interaction with Gαi, Gαt, and Gαo via a G-protein regulatory (GPR) motif that serves as a docking site for Gα-GDP. We recently reported the regulation of the AGS3-Gαi signaling module by a cell surface, seven-transmembrane receptor. Upon receptor activation, AGS3 reversibly dissociates from the cell cortex, suggesting that it may function as a signal transducer with downstream signaling implications, and this question is addressed in the current report. In HEK-293 and COS-7 cells expressing the α2A/D-AR and Gαi3, receptor activation resulted in the translocation of endogenous AGS3 and AGS3-GFP from the cell cortex to a juxtanuclear region, where it co-localized with markers of the Golgi apparatus (GA). The agonist-induced translocation of AGS3 was reversed by the α2-AR antagonist rauwolscine. The TPR domain of AGS3 was required for agonist-induced translocation of AGS3 from the cell cortex to the GA, and the translocation was blocked by pertussis toxin pretreatment or by the phospholipase Cβ inhibitor U73122. Agonist-induced translocation of AGS3 to the GA altered the functional organization and protein sorting at the trans-Golgi network. The regulated movement of AGS3 between the cell cortex and the GA offers unexpected mechanisms for modulating protein secretion and/or endosome recycling events at the trans-Golgi network.
Quality of Life in Patients Treated for Curable Rectal Cancer

Given the advances in oncologic outcome after treatment for rectal cancer, it is important to understand how therapy affects patients' long-term quality of life (QOL). In recent years a significant number of publications have used validated instruments to report QOL in patients treated for rectal cancer. Numerous factors are hypothesized to affect QOL after surgery for rectal cancer, including permanent stomas, the use of radiotherapy, type of rectal reconstruction, and several patient demographic factors. Although there are several limitations to these studies, current evidence indicates that a permanent stoma is not associated with as much impairment as previously hypothesized. Specifically, the data suggest that a permanent stoma is associated with greater impairment of sexual function and body image, while sphincter preservation is associated with numerous functional (defecation) problems. Radiation therapy may also contribute to a decrease in sexual QOL subscales. Bowel and sexual function appear to significantly affect quality of life. These findings are not consistent, however, as the studies have been methodologically flawed. Additionally, these studies are retrospective, sampling small heterogenous patient populations and using different QOL instruments. Further research is required to better understand factors associated with QOL, and to devise strategies for improving QOL following surgery for rectal cancer.
Revisiting current paradigms in computer assisted language learning research and development

Because Computer Assisted Language Learning (CALL) is amultidisciplinary field, many researchers in the area believeit is necessary to develop a more homogenous and rigorousapproach to CALL research and development. This paperdiscusses the current state-of-the-art in in the field andproposes a more inclusive approach to design and implementCALL projects. The opinions and facts presented here are basedon the procedures used to develop the TAGARELA system.
Period two automorphisms of UHF C*-algebras

Recently [7] Fack and Marechal classified the product symmetries of a UHF C*-algebra. Among these product symmetries there is a distinguished element si, whose fixed point algebra is UHF. (Since they dealt with product symmetries all fixed point algebras are automatically AF.) The symmetry s: is characterized, among product symmetries, by the property pm. This had been noted earlier by Kishimoto [ 151.
Recursive Partitioning for the Identification of Disease Risk Subgroups: A Case-Control Study of Subarachnoid Hemorrhage

Recursive partitioning is a nonparametric technique that produces a classification tree in which subjects are assigned to mutually exclusive subsets according to a set of predictor variables. We examined the utility of recursive partitioning as a supplement to logistic regression for the multivariable analysis of data from case-control studies, demonstrating the technique using data from women enrolled in a population-based study of subarachnoid hemorrhage. The classification tree produced by recursive partitioning consisted of three main risk subgroups: (1) elderly women who had long-standing hypertension and who were not smokers, (2) middle-aged women who were cigarette smokers and frequent binge drinkers, and (3) women in whom risk variables indicate relative estrogen deficiency (i.e., postmenopausal status, no recent exposure to hormone replacement therapy, cigarette smoking). As a supplemental method, recursive partitioning not only identifies subgroups with varying risks, but also may uncover interactions between variables that may be overlooked in the traditional application of logistic regression to case-control data.
Magnetic Flux, Angular Momentum, and Statistics

It is demonstrated that the orbital angular momentum ${l}_{z}$ of a particle of charge $q$ orbiting around a tube with magnetic flux $\ensuremath{\Phi}$ is quantized in units ${l}_{z}=\mathrm{integer}\ensuremath{-}\frac{q\ensuremath{\Phi}}{2\ensuremath{\pi}}$. A very simple physical argument for this is presented, and applied to understand the Dirac quantization condition and the charge-spin relation for particles bound to magnetic monopoles. The unusual statistics of flux-tube-charged-particle composites is discussed.
Skew estimation and feed-forward control in flangeless tape drives

Abstract An enhanced skew follow control system is presented to more accurately and reliably control the tape-to-head skew in tape systems with flangeless rollers. It features a novel feed-forward skew control system, based on a new skew estimation technique that allows obtaining skew from the information provided by one servo channel only. A disturbance observer provides an estimate of the lateral tape motion, which is used to estimate the absolute tape skew. The feed-forward controller utilizes that skew estimate to enhance the performance of a traditional feedback skew-following system and to enable skew follow operation if only one servo channel is active. The performance of the enhanced skew following method is illustrated by experimental results, both in combined operation with the classical feedback system and the feed-forward system and in stand-alone feed-forward mode.
Challenges to Conceptualizing and Actualizing Culturally Relevant Pedagogy: How Viable Is the Theory in Classroom Practice?:

Although culturally relevant pedagogy is widely espoused and applied in educational research and practice, it is often not commonly understood as a conceptual framework that advocates the elements of academic success, cultural competence, and sociopolitical consciousness. This study was a grassroots attempt to work collaboratively with a group of administrators and teachers at one urban school to define, implement, and assess culturally relevant pedagogy as a viable pedagogical tool. A qualitative approach that used the combined methods of action research and critical case study was employed for this study. Findings revealed deep structural issues related to teachers’ cultural bias, the nature of racism in school settings, and the lack of support to adequately implement theories into practice. The study also recommends further inquiry-based dialogue among scholars and practitioners to more consistently utilize the theory in academic research and in classroom instruction.
Effect of Major Deletions in the V1 and V2 Loops of a Macrophage-Tropic HIV Type 1 Isolate on Viral Envelope Structure, Cell Entry, and Replication

ABSTRACT Two HIV-1 envelope mutant proteins were generated by introducing deletions in the first and second hypervariable gp120 regions (V1 and V2 loops, respectively) of a macrophage-tropic primary HIV-1 isolate, SF162, to study the effect of the deleted sequences on envelope structure, viral entry, and replication potentials. The First mutant lacked 17 amino acids of the V1 loop and the latter 30 amino acids of the V2 loop. A comparison of the immunochemical structure of the wild-type and mutant monomeric and virion-associated gp120 molecules revealed that the V1 and V2 loop deletions differentially altered the structure of the V3 loop, the CD4-binding site, and epitopes within conserved regions of gp120. Regardless of differences in structure, both mutated envelope proteins supported viral replication into peripheral blood mononuclear cells to levels comparable to those of the wild-type SF162 virus. However, they decreased the viral replication potential in macrophages, even though they did not alter t...
Farm Development in Poor Countries: The Disputed Consequences for U.S. Farm Trade

A growing body of evidence suggests that farm development in poor countries is not necessarily menacing to U.S. farm trade. To the contrary, by helping to stimulate broadbased income growth in poor countries, which is often followed by dietary enrichment and food import expansion, farm development in poor countries can actually be beneficial to U.S. farm trade. Here we shall review some of the evidence which agricultural economists have recently put forward to support this paradoxical argument, and we shall ask why this evidence has not yet been persuasive to the U.S. farm community. In poor countries, where incomes are low, where diets are not yet rich, and where a majority of citizens often depend upon farming for income and employment, rapid agricultural development can stimulate the broad-based income growth, and eventually the industrial development, usually necessary to turn loose pent-up demands for dietary enrichment. The paradoxical result can be that local food consumption may grow even more rapidly than local food production, and the net farm imports of agriculturally successful developing countries can then actually increase, to the presumed benefit of U.S. farmers. A significant body of evidence has recently been assembled to document this paradoxical claim. In 1979 Bachman and Paulino examined the trade consequences of rapid food production growth in sixteen developing countries and found that while the proportion of domestic food consumption satisfied by imports generally fell in these countries, net imports of staple foods nonetheless increased. Annual net staple food imports in these agriculturally successful poor countries actually rose in volume by 133% between 1961-65 and 1974-76 (Bachman and Paulino, p. 14). A similar pattern of rapid food import growth has more recently been documented by Lee and Shane, in two developing countries-Malaysia and Brazil-often cited as threats to U.S. farm trade. Both of these coun-
Multilevel Gradient Uzawa Algorithms for Symmetric Saddle Point Problems

In this paper, we introduce a general multilevel gradient Uzawa algorithm for symmetric saddle point systems. We compare its performance with the performance of the standard Uzawa multilevel algorithm. The main idea of the approach is to combine a double inexact Uzawa algorithm at the continuous level with a gradient type algorithm at the discrete level. The algorithm is based on the existence of a priori multilevel sequences of nested approximation pairs of spaces, but the family does not have to be stable. To ensure convergence, the process has to maintain an accurate representation of the residuals at each step of the inexact Uzawa algorithm at the continuous level. The residual representations at each step are approximated by projections or representation operators. Sufficient conditions for ending the iteration on a current pair of discrete spaces are determined by computing simple indicators that involve consecutive iterations. When compared with the standard Uzawa multilevel algorithm, our proposed algorithm has the advantages of automatically selecting the relaxation parameter, lowering the number of iterations on each level, and improving on running time. By carefully choosing the discrete spaces and the projection operators, the error for the second component of the solution can be significantly improved even when comparison is made with the discretization on standard families of stable pairs.
Facilitation of physical performance by means of a cognitive strategy.

The purpose of this investigation was to evaluate the efficacy of a dissociative cognitive strategy in facilitation of endurance performance. A pilot study of endurance performance was conducted in which 15 subjects ran to exhaustion on a motor-driven treadmill at 80% of maximal aerobic power (MAP). These subjects were randomly assigned to a cognitive strategy (dissociation), placebo, or control group and retested. The group employing the cognitive strategy was superior (+19%) to the control and placebo groups. In the second experiment control (N = 13) and dissociation (N = 14) groups were tested at 80% of MAP under baseline conditions, and again at the same metabolic demand with the exception that subjects in the experimental group employed the dissociative cognitive strategy used in the pilot study. The two groups were found to be remarkably similar on all physiological measures, but the dissociation group experienced a significant performance gain. The exercise metabolite, blood lactate, was similar in the two groups, and plasma catecholamine levels were higher in the dissociation group. This implies that distraction of sensory discomfort enabled subjects in the dissociation group to tolerate a greater amount of discomfort for a longer period of time. These findings suggest that a cognitive strategy based upon dissociation of sensory input can facilitate endurance performance on tasks of the type employed in the current investigation.
Electronic and optical properties of Ge-Si superlattices

Abstract Germanium and silicon elemental semiconductors are indirect bandgap, cubic materials that are used in the manufacture of the great majority of semiconductor electronic devices. Epitaxial techniques, largely borrowed and adapted from group III-V compound semiconductor technology, have been applied successfully to produce heterostructures and superlattices from Ge and Si. Theory shows that some of these structures behave like direct bandgap materials, while other structures can be used for optical second harmonic generation. On the other hand, it has been well understood for many years that neither silicon, nor germanium, nor any germanium-silicon alloy could ever show such behaviour. Recent progress in germanium-silicon heterostructures is reviewed in the context of developing a new materials system for photonic devices based entirely on silicon and germanium and suitable for optical waveguides, modulators, sources, and detectors.
A connector integrated mm-wave antenna

In this paper, we present a new concept of using existing electronic connectors, such as micro USB and audio phone jack, as the main structure of mm-wave antennas. The integrated antenna itself exhibits good radiation performance for 60GHz application. The modified connectors perform original connectivity when plugged and radiate mm-wave signal when unplugged or plugged with radiating enhancing structures. The combinations almost consume no extra footprint of the device's circuit board.
IKONOS Spatial Resolution and Image Interpretability Characterization

This paper contains research from five individual projects to characterize the spatial performance of the IKONOS commercial imaging sensor. The end result of the projects is determination of the spatial image quality of IKONOS data prodicts in terms of the National Imagery Interpretability Rating Scale (NIIRS), the system Modulation Transfer Function (MTF), the system stability over the first year, the characteristics of the Space Imaging MTF Compensation (MTFC) procedure, and the application-specific capabilities of IKONOS imagery. Both panchromatic and multispectral imagery were evaluated. Major conclusions of this work are that the system was stable im imaging performance during the first year of operation, tha its MTF meets the specification for the NASA Scientific Data Purchase program, that the initial MTFC processing appears to be transposed in the in-track and the cross-track directions, that the MTFC results in a noise amplification of 2x to 4x in addition to sharpening the imagery, and that IKONOS panchromatic imagery achieves an average NIIRS rating of 4.5.
Prediction of outcome in "resectable" esophageal carcinoma.

A retrospective review was performed of 51 patients with esophageal carcinoma, deemed “resectable” by preoperative workup (e.g., CT scan, barium swallow), who presented to Hahnemann University Hospital between 1980 and 1991. This represented 21.8% of the total number of patients (234) with esophageal cancer who presented during that time period. At exploration, only 21 of the 51 patients (41%, or 9% overall) were truly resectable; 59% had more extensive disease than was appreciated preoperatively and that precluded resection for cure. Of the 21 patients resected for cure, 24% were alive at two years and only 5% were alive at 3 years. Neither age, gender, tumor type nor location in the esophagus significantly affected overall survival. Furthermore, none of these parameters, taken as independent variables, were able to predict true resectability at the time of operation. © 1993 Wiley-Liss, Inc. We conclude that preoperative assessment of resectability, even in those patients who appear to be good candidates for cure, remains imprecise at best. Given an operative mortality rate of 6–8% (in most series) and an overall 3- to 5-year survival rate of less than 10% (even in patients thought to have had curative resections), we reinforce the fact that meticulous patient selection and multimodality management strategies remain the keys to making any impact on this disease. © 1993 Wiley-Liss, Inc.
Controlled Traffic Impacts on Physical and Hydraulic Properties in an Intensively Cropped No-Till Soil

Changes in soil properties with wheel traffic involving intensive cropping systems under no-till (NT) are not well understood. We assessed the 8-yr impacts of intensive cropping systems and wheel traffic on soil physical and hydraulic properties and their relationships under NT on a Ladysmith silty clay loam (a fine, smectitic, mesic Udertic Argiustoll) near Hesston, KS. Winter wheat (Triticum aestivum L.) (W), grain sorghum [Sorghum bicolor (L.) Moench] (S), double-crop grain sorghum (*S), soybean [Glycine max (L.) Merr.] (B), and double-crop soybean (*B) arranged in S-S-S, W*S-S-B, W-S-B, and W*B-S-B rotations were studied. In doubled crops, sorghum or soybean was planted immediately after wheat harvest. Cropping systems had less of an effect on soil properties than wheel traffic. Wheel traffic increased bulk density (ρ b ) from 1.16 ± 0.06 (mean ± SD) to 1.38 ± 0.03 Mg m -3 , cone index (CI) from 1.78 ± 0.29 to 3.10 ± 0.15 MPa, shear strength (SHEAR) from 23 ± 2.2 to 6 1 ± 5.2 kPa, and aggregate tensile strength from 377 ± 80 to 955 ± 148 kPa over nontrafficked rows in the 0- to 7.5-cm depth. Wheel compaction reduced cumulative infiltration by 40 to 120 times except in S-S-S. It also reduced the logarithm of the saturated hydraulic conductivity (log K sat ), soil water retention at 0 kPa, plant-available water, effective porosity (φ e ), and the volume of > 50-μm pores. An increase in ρ b , CI, and SHEAR linearly reduced φ e (r > -0.74), which, in turn, reduced cumulative infiltration and log K sat (r > 0.74). Data strongly support the need for using controlled traffic to reduce the adverse impacts of wheel traffic on soil physical quality.
A system dynamics model of a JIT-kanban system

Abstract Just-In-Time production systems are gaining tremendous popularity in modern production environments. Based on the concept of producing exactly the required quantity and type of product, these systems display an excellent ability to adapt to changes in demand as well as permitting greatly reduced work-in-process inventories. JIT systems often make reference to “Kanbans” which are the inventory control cards used in most JIT environments. A JIT-Kanban system is one where production is pulled through the process rather than conventional MRP push. This fundamental difference is what gives JIT-Kanban systems their unique characteristics. This paper investigates some of these unique characteristics of JIT-Kanban systems by way of a dynamic simulation model. Using system dynamics concepts, the behavior of the system under the stimulus of various exogenous factors is demonstrated.
Interaction of Bovine Leukemia Virus Transactivator Tax with bZip Proteins

The bovine leukemia virus transactivator, BLV Tax, augments transcription from three imperfect 21-bp repeats in the viral transcriptional regulatory region. Each BLV 21-bp repeat contains a cAMP response element (CRE) in the center and unique 5′ and 3′ neighboring sequences which are crucial for the transcriptional activation by BLV Tax. Here we describe the interactions of recombinant BLV Tax with cellular bZip proteins. The recombinant BLV Tax, tagged at the carboxy terminus with a hexahistidine extension, was prepared by solubilization in 6Mguanidine hydrochloride and renaturation on the Ni2+-chelating Sepharose gel matrix. The renatured BLV TaxH6activates the BLV LTR when introduced into HeLa cells by scrape loading. Furthermore, the purified BLV TaxH6enhances binding of members of the CREB/ATF family of bZip proteins to CRE motifs by interacting with their bZip domainsin vitro.Chemical cross-linking indicates that dimerization of bZip proteins such as CREB becomes greatly facilitated in the presence of BLV Tax. These results suggest that BLV Tax interacts directly with CREB/ATF-like factors to activate viral mRNA transcription.
The classic : a morphogenetic matrix for differentiation of bone tissue.

This Classic Article is a reprint of the original work by Marshall R. Urist, A Morphogenetic Matrix for Differentiation of Bone Tissue. An accompanying biographical sketch of Marshall R. Urist, MD is available at DOI 10.1007/s11999-009-1067-4; a second Classic Article is available at DOI 10.1007/s11999-009-1068-3; and a third Classic Article is available at DOI 10.1007/s11999-009-1069-2. The Classic Article is © 1970 by Springer and is reprinted with permission from Urist MR. A morphogenetic matrix for differentiation of bone tissue. Calc Tiss Res. 1970:4(Suppl);98–101.
Effect of chromosomal locus, GC content and length of homology on PCR-mediated targeted gene replacement in Saccharomyces

Targeted gene replacement (TGR) using fragments generated by PCR is a widely-used technique for deleting genes in Saccharomyces cerevisiae. We found that the efficiency of this procedure, defined as the fraction of transformants that delete the targeted gene, varied by >10-fold depending on the sequence being targeted. We examined the effect of chromosomal position, length of homology and GC content on TGR efficiency. When URA3 was positioned at five different chromosomal locations, the efficiency of replacing this gene with LEU2 remained the same. Similarly, varying the length of homology from 35 to 60 bp had only a small effect on the efficiency of targeting (<50%), though an increase in the length of homology to 200 bp on one end of the disruption fragment did increase TGR efficiency. Strikingly, as GC content in the target sequence increased, the efficiency of targeting also increased. When TGR efficiency was high, the frequency of untargeted integration events was low. These results suggest two strategies for designing TGR primers: (i) use 40 bp targeting sequences containing 40-50% GC, and (ii) if necessary, increase TGR efficiency by extending the length of homology on one end of the disruption fragment.
Sources of granitoid magmas at convergent plate boundaries

Source rocks for magmas in subduction zones include subducted oceanic crust, mantle peridotite, and metamorphic rocks of continental crust. Phase relationships for these materials, including the compositions of liquids developed at various pressures, temperatures, and with H_2O and CO_2, provide a starting point for the petrogenesis of granitoid intrusions. Four thermal structures are obtained by combinations of warm or cool subducted oceanic crust, and cool or warm overlying mantle. These encompass the range of dehydration and melting sites and processes likely to occur in subduction. Petrological structures derived by combining major rock structures with the assumed thermal structures and the phase relationships of materials indicate that initial magma generation in any of the three major source rocks may be followed by a sequence of events leading to the intrusion of granitoid magmas into continental crust. Magmas of different compositions may rise independently from different sources at different depths, introducing the prospect of hybridization and magma mixing in the mantle and continental crust. Many granitoid intrusions are initiated by the transfer of heat and magma from below the continental crust.
Electrolyte permeability and electromotive action of mosaic membranes composed of porous and liquid parts of high ionic selectivity for ions of opposite signs

A theory is presented of the electromotive and ion permeability properties of membranes which consist of a mosaic of highly ion selectiveporous membrane areas of ion exchanger nature and of areas of highly ion selectiveliquid ion exchanger membranes, the two types of areas being exclusively permeable to ions of opposite sign. It is demonstrated that, with properly chosen membranes, the preferential permeability of such porous-liquid mosaic membranes for ions of one sign of charge will be the opposite of that apparently indicated by their electromotive action. The theory is based on the fact that the movement of ions across the porous membranes occurs in the dissociated state and in most instances is quantitatively linked to the resistance according to the Nernst-Einstein equation. The penetration of ions across liquid ion exchanger membranes, however, takes place essentially in a nondissociated state, and, as determined by self-exchange studies with radioactive tracers and stirred membranes, occurs at rates far in excess of those across porous membranes of the same resistance. For the theoretical treatment the simplest case, two-membrane macro-model concentration cells, is discussed in detail. Qualitatively, it is evident that the ratio of the permeability of anions and cations across such porous-liquid mosaic membranes ordinarily will be strongly in favor of the ions which penetrate across its liquid parts; contrariwise, the electromotive actions of the mosaic membranes ordinarily are dominated by its porous parts. Electric currents flow through all mosaic membranes; the strenghth of the current in a model cell may be calculated from the concentration potentials arising separately across the two membranes, and the resistances of the membranes and of the two solutions. From the strength of the current, the sign and the magnitude of the concentration potential arising in the model cell may be computed; in many instances it should closely approach the concentration potential across the porous membrane. For the test of this theory with two-membrane macro-mosaic models, the electrolyte of choice for experimental reasons was RbSCN, tagged with86Rb+ and S14CN−. The porous membranes were polystyrene sulfonic acid collodion matrix membranes; the liquid membranes consisted of 0.02m trioctyl propyl ammonium thiocyanate in 1-decanol. The ratios of the permeabilities across the model mosaic membranes determined by conventional rate of self-exchange measurements showed, as expected, that the permeability of the SCN− ions is larger, up to 3600 times larger, than that of the Rb+ ions. The potentials arising in these models agreed within the limits of experimental error with those predicted by theory, closely approaching that arising at the cation selective porous membranes.
The photochemical oxidation of A2E results in the formation of a 5,8,5′,8′-bis-furanoid oxide

Abstract With age and certain diseases, the retinal pigment epithelium (RPE) accumulates a complex mixture of fluorophores generally called lipofuscin. This mixture has been implicated in those diseases via several possible mechanisms including photochemically mediated damage and detergent effects. Recently, a component of that mixture has been identified, a bis-retinoid pyridinium compound called A2E. Furthermore, the photolysis of this compound has been shown to lead to a series of photooxidation products each differing by 16 amu; with the addition of up to a total of nine oxygen atoms to A2E. It has been suggested that these products consist of a series of epoxides forming along the acyclic side chains. The present study reinvestigates this hypothesis and demonstrates that the bis-oxygenated product is in fact a relatively stable 5-8 5′-8′-bis-furanoid oxide. This is in agreement with the oxidation products observed for a homologue of A2E, β-carotene. In addition, it was found that the bis-oxygenated photoproduct of A2E contained a mixture of symmetrical and unsymmetrical oxidized products where the second oxygen was present in the cyclohexenyl ring structure in the unsymmetrical product. Most importantly, both of these oxidation products of A2E were detected in lipofuscin extracts from human RPE cells, suggesting that these processes occur in vivo.
Particulate matter characterization by gray level co-occurrence matrix based support vector machines

An efficient and highly reliable automatic selection of optimal segmentation algorithm for characterizing particulate matter is presented in this paper. Support vector machines (SVMs) are used as a new self-regulating classifier trained by gray level co-occurrence matrix (GLCM) of the image. This matrix is calculated at various angles and the texture features are evaluated for classifying the images. Results show that the performance of GLCM-based SVMs is drastically improved over the previous histogram-based SVMs. Our proposed GLCM-based approach of training SVM predicts a robust and more accurate segmentation algorithm than the standard histogram technique, as additional information based on the spatial relationship between pixels is incorporated for image classification. Further, the GLCM-based SVM classifiers were more accurate and required less training data when compared to the artificial neural network (ANN) classifiers.
'Dark' Z implications for Parity Violation, Rare Meson Decays, and Higgs Physics

General consequences of mass mixing between the ordinary $Z$ boson and a relatively light ${Z}_{d}$ boson, the ``dark'' $Z$, arising from a $U(1{)}_{d}$ gauge symmetry, associated with a hidden sector such as dark matter, are examined. New effects beyond kinetic mixing are emphasized. $Z\mathrm{\text{\ensuremath{-}}}{Z}_{d}$ mixing introduces a new source of low energy parity violation well explored by possible future atomic parity violation and planned polarized electron scattering experiments. Rare $K(B)$ meson decays into $\ensuremath{\pi}(K){\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$ ($\ensuremath{\ell}=e$, $\ensuremath{\mu}$) and $\ensuremath{\pi}(K)\ensuremath{\nu}\overline{\ensuremath{\nu}}$ are found to already place tight constraints on the size of $Z\mathrm{\text{\ensuremath{-}}}{Z}_{d}$ mixing. Those sensitivities can be further improved with future dedicated searches at $K$ and $B$ factories as well as binned studies of existing data. $Z\mathrm{\text{\ensuremath{-}}}{Z}_{d}$ mixing can also lead to the Higgs decay $H\ensuremath{\rightarrow}Z{Z}_{d}$, followed by $Z\ensuremath{\rightarrow}{\ensuremath{\ell}}_{1}^{+}{\ensuremath{\ell}}_{1}^{\ensuremath{-}}$ and ${Z}_{d}\ensuremath{\rightarrow}{\ensuremath{\ell}}_{2}^{+}{\ensuremath{\ell}}_{2}^{\ensuremath{-}}$ or ``missing energy,'' providing a potential hidden sector discovery channel at the Large Hadron Collider. An illustrative realization of these effects in a 2 Higgs doublet model is presented.
DNA damage-induced G2/M checkpoint in SV40 large T antigen-immortalized embryonic fibroblast cells requires SHP-2 tyrosine phosphatase.

DNA damage induced by radiation or DNA-damaging agents leads to apoptosis and cell cycle arrest. However, DNA damage-triggered signal transduction involved in these cellular responses is not well understood. We previously demonstrated an important role for SHP-2, a ubiquitously expressed SH2 domain-containing tyrosine phosphatase, in the DNA damage-induced apoptotic response. Here we report a potential role for SHP-2 in a DNA damage-activated cell cycle checkpoint. Cell cycle analysis and the mitotic index assay showed that following DNA damage induced by cisplatin or γ-irradiation, the G2 (but not S) arrest response was diminished in SV40 large T antigen-immortalized embryonic fibroblast cells lacking functional SHP-2. Notably, reintroduction of wild-type SHP-2 into the mutant cells fully restored the DNA damage-induced G2 arrest response, suggesting a direct role of SHP-2 in the G2/M checkpoint. Further biochemical analysis revealed that SHP-2 constitutively associated with 14-3-3β, and that Cdc25C cytoplasmic translocation induced by DNA damage was essentially blocked in SHP-2 mutant cells. Additionally, we showed that following DNA damage, activation of p38 kinase was significantly elevated, while Erk kinase activation was decreased in mutant cells, and treatment of SHP-2 mutant cells with SB203580, a selective inhibitor for p38 kinase, partially restored the DNA damage-induced G2 arrest response. These results together provide the first evidence that SHP-2 tyrosine phosphatase enhances the DNA damage G2/M checkpoint in SV40 large T antigen immortalized murine embryonic fibroblast cells.