cssi/SciSciGPT-SciSciNet huggingface dataset:
Moving template analysis of crack growth—II. Multiple crack extension and benchmarking

Abstract In Part I of this series [J. Padovan and Y. H. Guo, Engng Fracture Mech. 48,405–425 (1994)], a moving template scheme was developed which can model the propagation of long cracks possessing complex topologies and mixed mode behavior. This part extends the procedure to the propagation of multiple fatigue cracks. The methodology is benchmarked over a wide variety of single and multiple crack problems involving complex mixed mode behavior. This includes such problem features as compound loading, multiple cracks, crack wake induced shading of the unfolding stress distribution, different growth rates for the various cracks as defined by the stress redistribution, as well as mixed mode behavior. Additionally, formal expressions are derived which illustrate the advantages of employing the HPT scheme (hierarchical substructuring) to streamline the computational effort. These point to significant cost effective improvements.
Migration, natality and fertility: some Caribbean evidence.

This research note explores the macrolevel impact of external migration on the demographic behavior of Caribbean islands. The analysis provisionally argues that the massive mobility of Caribbean peoples in the postwar era--primarily of young reproductive (especially female) working-age cohorts--has inversely affected natality and population growth in sending societies and reversed these effects in receiving societies. Results further suggest secondarily and quite indirectly that migration may also influence fertility patterns in similar directions through the impacts of age-sex imbalances on mating behavior and family formation. (EXCERPT)
Clinical evaluation of a new esophageal electrode, with particular reference to the bipolar esophageel electrocardiogram part II. Observations in cardiac arrhythmias☆

Abstract 1. 1. The application of the salt-bridge method of esophageal electrocardiographic registration to the development of a simple and clinically reliable bipolar esophageal lead has been outlined. The results of multichannel, multilevel esophageal lead surveys made with this device upon 26 subjects with normal sinus mechanism and 74 with various cardiac arrhythmias are reported here. The leads which were routinely recorded simultaneously in these surveys include unipolar registration from the proximal and distal members of the lead assembly (VE P and VE D ), the difference in potential between these two members (Lead BE), and a conventional extremity lead (usually Lead II). 2. 2. A careful and extensive analysis of the group of subjects with normal sinus rhythm confirms that both the unipolar and bipolar esophageal leads greatly exceed the capability of conventional body surface leads in depicting the forces of atrial depolarization and repolarization. In this group the bipolar esophageal leads appeared to have certain advantages as compared to the unipolar leads, and in no instance did they prove inferior to the unipolar leads. 3. 3. In our evaluation of the group of subjects with cardiac arrhythmias the esophageal leads offered unsurpassable diagnostic superiority as compared to the conventional leads. In a number of cases the bipolar esophageal lead was decidedly better than the unipolar leads, although this was not invariably so. 4. 4. Our clinical observations of the unipolar and bipolar esophageal electrocardiograms appear to confirm the theoretical principles which were previously developed in this laboratory. As anticipated, the bipolar lead has proved to be particularly sensitive to alterations in the time course of atrial depolarization. It also provides a ready means for sorting atrial from ventricular deflections, especially in situations in which they occur concomitantly. 5. 5. On the basis of the experiences reported here, we believe that no complicated or perplexing arrhythmia will have been studied adequately without the benefit of esophageal tracings. The relative technical simplicity of the salt-bridge principle as applied to unipolar and bipolar esophageal registration greatly minimizes the demands which such a procedure would ordinarily impose upon the physician's time and energy.
Wireless transmission of cardiac action potentials with ultrasonically guided insertion of silicon probes

This paper reports on the coupling of ultrasonically guided cardiac probes with wireless transmission of cardiac action potentials for applications in monitoring the 3D electrical onset of ventricular fibrillation. An application specific integrated circuit has been designed with a 40 dB amplifying stage and a frequency modulating oscillator to wirelessly transmit the recorded action potentials. Combined with the ultrasonically inserted cardiac probe that reduces penetration force, this system demonstrates the initial results in wireless monitoring of 3D action potential propagation.
The Accounting Profession: Expert Witness and/or Advocate?

Abstract In attempting to serve the public interest, the accounting profession often finds itself struggling in the midst of opposing forces. This conflict stems from the separate, and in part contradictory, functions the profession serves. In one of its roles the profession acts on behalf of the state—providing testimony regarding the definition of income and the acceptability of accounting methods. The profession also performs the adversarial function of advising entities on calculating and minimizing taxes. The development of LIFO for tax purposes provides a good historical example of the accountant's dual responsibility. Through the application of a theoretical framework developed by Puxty, this paper examines the accountant's involvement in the development of LIFO to determine the degree of success with which the profession has discharged its duties to opposing constituencies. It appears that, in this case, the function of advisor was ultimately subordinated to the role of tax minimizer.
Mask inspection technologies for 22nm HP and beyond

Reticle quality and the capability to qualify a reticle are key issues for EUV Lithography. We expect current and planned optical inspection systems will provide inspection capability adequate for development and production of 2X HP masks. We illustrate inspection technology extendibility through simulation of 193nm-based inspection of advanced EUV patterned masks. The influence of EUV absorber design for 193nm optical contrast and defect sensitivity will be identified for absorber designs of current interest.
The collagen of osteogenic cartilage in the embryonic chick

Abstract The diaphyseal region of tibiae, and vertebral bodies from 8-day chick embryos were cultured in the presence of tritiated proline and the radioactive proteins were extracted and co-purified with carrier collagen. Chromatography on carboxymethylcellulose indicated that the radioactively labelled proteins eluted as a single peak which coincided with the carrier α1 chains. On DEAE-cellulose, the radioactively labelled α1 chains eluted with authentic cartilage α1 (II) carrier. The transitory chondrogenic regions of the embryo thus produce a collagen molecule similar, if not identical, to the principal collagen molecule found in cartilaginous structures in the adult.
Modeling social insect populations II: Optimal reproductive strategies in annual eusocial insect colonies

We examined the optimal reproductive strategies for eusocial insects with an annual life cycle. A model is constructed for the growth of workers and reproductives as a function of the resources allocated to each. We then compute the allocation schedule which yields the maximum number of reproductives by season's end. Field observations appear to confirm the prediction of our model: the optimal strategy is to invest in colony growth until approximately one generation before the season's end, whereupon worker production ceases and reproductive effort is switched entirely to producing queens and males. Similar all-or-none strategies are observed in other biological contexts, and their optimality is proven here. Finally, we calculate the fraction of the total season's resources allocated to reproductives from which we can estimate the ergonomic efficiency of the colony with respect to reproductive success.
Another Look at Armstrong's Combinatorialism

The core idea of David Armstrong’s combinatorial theory of possibility is attractive. Rearrangement is the key to modality; possible worlds result from scrambling bits and pieces of other possible worlds. Yet I encounter great dif culty when trying to formulate the theory rigorously, and my best attempts are vulnerable to counterexamples. The Leibnizian biconditionals relate possibility and necessity to possible world and true in:
“Neurotech at the interface: Connecting the engineering and physical sciences with life sciences”

Basic research forms the first links in the chain of research, development and testing needed to yield the new healthcare treatments and technologies that the public anticipates will greatly enhance their lives and improve healthcare. For over 50 years, the National Science Foundation (NSF) has built a solid record enabling learning, discovery and innovation at the research frontier, ultimately leading to applications of great benefit to humanity. NSF invests in the best ideas generated by scientists, engineers and educators working at the frontiers of discovery and knowledge, and across all fields of research and education. NSF also emphasizes the necessity of integrating research with education, and plays a major role in training the next generation of innovators and researchers, as well as educating the science and engineering workforce and the public. Across the spectrum of biology, mathematics and physical science, social and behavioral science, geoscience, engineering, computer and information science, and education, NSF-funded research results are already serving new biomedical objectives and facilitating progress in the global arena of human health.
Structural rearrangements in the active site of smooth-muscle myosin.

Structural rearrangements of the myosin upper-50 kD subdomain are thought to play a key role in coordinating actin binding with nucleotide hydrolysis during the myosin ATPase cycle. Such rearrangements could open and close the active site in opposition to the actin-binding cleft, helping explain the opposing affinities of myosin for actin and nucleotide. To directly examine conformational changes across the active site during the ATPase cycle we have genetically engineered a mutant of chicken smooth-muscle myosin, F344W motor domain essential light chain, which contains a single tryptophan (344W) located on a short loop between two alpha helixes that traverse the upper-50 kD subdomain in front of the active site. Fluorescence resonance energy transfer was examined between the 344W donor probe and 2′(3′)-O-(N-methylanthraniloyl) (mant)-nucleotide acceptor probes in the active site of this construct. The observed fluorescence resonance energy transfer efficiencies were 6.4% in the presence of mant ADP and 23.8% in the presence of mant ATP, corresponding to distances of 33.4 A and 24.9 A, respectively. Our results are consistent with structural rearrangements in which there is an 8.5-A closure between the 344W residue and the mant moiety during the transition from the strongly (ADP) to weakly (ATP) actin-bound states of the myosin ATPase cycle.
Pollinator body size mediates the scale at which land use drives crop pollination services

Ecosystem services to agriculture, such as pollination, rely on natural areas adjacent to farmland to support organisms that provide services. Native insect pollinators depend on natural or semi‐natural land surrounding farms for nesting and alternative foraging resources. Despite interest in conserving pollinators through habitat restoration, the scale at which land use affects pollinators and thus crop pollination services is not well understood. We measured abundance of native, wild bee pollinators and the pollination services they provided to highbush blueberry Vaccinium corymbosum L. crops at 16 sites that varied in the proportion of surrounding agricultural land cover at both the field scale (300‐m radius) and the landscape scale (1500‐m radius). We designed our study such that agricultural land cover at the field scale was uncorrelated with agricultural cover at the landscape scale across sites. We used model selection to determine which spatial scale better predicted aggregate bee abundance, abundance of large versus small bees and crop pollination services. We found that, overall, bees responded more strongly to field‐scale than to landscape‐scale land cover, but the scale at which land cover had the strongest effect varied by bee body size. Large bees showed a negative response to increasing agricultural cover at both scales, but were most strongly affected by the landscape scale. Small bees were negatively affected by agricultural land cover but only at the field scale, while they had a small positive response to agricultural cover at the landscape scale. Aggregate pollination services from native bees were more strongly influenced by field‐scale agricultural cover, due to the combined effects of both large and small bees responding at that scale. Synthesis and applications. Bee abundance and pollination services were strongly determined by field‐scale agricultural cover, suggesting that field‐scale set‐asides may provide significant benefits to pollination services. Further, we found that pollinators respond differently to land use depending on body size, but all groups of bees benefit from decreasing agricultural cover at the field scale. Therefore, small‐scale modifications to habitat can have significant impacts on both pollinator abundance and pollination services to crop plants.
Influence of Age and IB Status After Resection of Node-Negative Non-Small Cell Lung Cancer

Background Anatomic segmentectomy has been proposed as a reasonable alternative to lobectomy in the management of small early-stage non-small cell lung cancers. We reviewed our outcomes with anatomic segmentectomy versus lobectomy for stages IA and IB non-small cell lung cancer stratified by age and stage. Methods We conducted a retrospective review of prospectively-collected data analyzing outcomes after anatomic segmentectomy (n = 305) for stage IA (n = 187) or IB (n = 118) NSCLC from 1999 to 2010. Lobectomy was performed in 594 patients for stage IA (n = 290) and IB (n = 304) disease during the same period. Surgical approach was stratified by stage and by the following age groups: less than 70, 70 to 79, and 80 or greater. Primary outcome variables included complications, mortality, recurrence patterns, and survival. Mean follow-up was 37 months. Results Segmentectomy was associated with reduced complications (43.6% vs 58.7%) and mortality (0% vs 7.8%) in patients greater than 80 years old, without a difference in recurrence rates. There was no difference in complications or mortality in the younger age groups. Freedom from recurrence was similar between segmentectomy and lobectomy for stage IA tumors across all age groups. A reduced recurrence-free survival was seen with segmentectomy for stage IB tumors, especially with visceral pleural invasion (median 22.7 vs 29.6 months), p = 0.048). Conclusions Segmentectomy appears to be a reasonable approach for early-stage NSCLC in patients 80 years of age or greater due to reduced morbidity and mortality with equivalent freedom from recurrence. Although equivalent survival was seen in all age groups for stage IA, these data further support the use of lobectomy for resection of stage IB tumors.
The developmental expression of the gene for TFIIIA in Xenopus laevis

The sequence of the trans-acting positive transcription factor TFIIIA has been deduced by sequencing cDNA and genomic DNA clones. Using DNA from a homozygous diploid animal we show that there is one gene for TFIIIA per haploid genome of X. laevis. Protein sequencing of proteolytic fragments of TFIIIA orients the protein in its interaction with the internal control region (ICR) of the 5S RNA gene. The protein lies along the DNA with its carboxyl terminus at the 5' end of the ICR and its amino terminus at the 3' end. The developmental pattern of TFIIIA and its mRNA during oogenesis and embryogenesis are consistent with the idea that the abundance of TFIIIA plays an essential role in the developmental change in 5S RNA gene expression. The change to almost exclusive somatic 5S RNA gene expression by gastrulation occurs using either the TFIIIA that was synthesized by oocyte and/or TFIIIA synthesized from maternal mRNA.
Achieving a Successful Pregnancy in Women with Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a disease of complex and still poorly understood cause and of variable phenotypes. It is characterized by anovulation, hyperandrogenism, and polycystic ovaries. Infertility is commonly present. A variety of methods has been used successfully to achieve pregnancy in women with PCOS. Maintenance of pregnancy is complicated by a higher rate of premature spontaneous abortions and high risk of gestational diabetes, hypertension, and preeclampsia. However, with careful monitoring and treatment, the outcome of pregnancy in most women with PCOS is excellent.
Divine Violence: Spectacle, Psychosexuality, & Radical Christianity in the Argentine “Dirty War”

Divine Violence: Spectacle, Psychosexuality, & Radical Christianity in the Argentine “Dirty War.” Frank Graziano. Boulder, CO: Westview Press, 1992. xi + 328 pp., index. $58.00 (cloth), $19.95 (paper). ISBN 0-8133-8231-9, ISBN 0-8133-8232-7.
Construction and application of a modified "gene machine": a circular concentrating preparative gel electrophoresis device employing discontinuous elution.

Abstract A modified version of a preparative circular gel electrophoresis apparatus, first described by Edwin Southern (Medical Research Council, University of Edinburgh, Edinburgh, Scotland), has been constructed. The apparatus fractionates a large volume of sample into concentric bands which migrate toward a small circular collection chamber. Samples exiting the gel into the collection chamber are concentrated against a dialysis membrane which encloses the inner electrode and are pumped from this center chamber into a fraction collector at fixed time intervals. The apparatus has been employed to fractionate samples of DNA (10 mg) by electrophoresis through either agarose or acrylamide gels. Two examples of nucleic acids which have been successfully fractionated are given: restriction endonuclease cleavage fragments of total soybean DNA, and a heterogeneous mixture of covalently closed circular plasmid DNA from Bacillus megaterium. Franctionated DNA is suitable for molecular cloning directly from acrylamide and, after one additional treatment, from agarose. The run time for DNA treated with restriction endonuclease is from 24 to 48 h. Purification of 60- to 200-fold is common for a DNA restriction fragment from a total genome.
Two-component exciton model: Basic formalism away from shell closures.

A closed form version of the two-component exciton model is derived. Discussions of corrections for the Pauli exclusion principle, of the expected behavior of the residual two-body matrix elements, and of the relative merits of different types of reaction calculations within the exciton model are presented. Calculations verify the validity of the equal a priori probabilities assumption underlying exciton model calculations and demonstrate that the one- and two-component models produce very similar results when similar assumptions are made about the relative probabilities of exciting proton and neutron degrees of freedom.
Silencing is golden: negative regulation in the control of neuronal gene transcription

Recent work has identified negative-acting DNA regulatory elements that function to prevent the expression of neuronal genes in non-neuronal cell types or in inappropriate neuronal subtypes. In some cases, the protein factors that interact with these silencer elements have been isolated and characterized. For example, the recently cloned silencer-binding factor NRSF/REST is a novel zinc-finger protein that interacts with silencer elements in a number of neuron-specific genes. These data suggest that negative regulation plays a major role in determining the diverse patterns of gene expression within the nervous system.
Construction of discrimination ellipsoids for surface colors by the method of constant stimuli

First, methods to define the region of colors indistinguishable from a standard color are reviewed, both for aperture and surface colors. Then, an algorithm to define discrimination ellipsoids for surface colors in (x,y,l) space is described, where 1 is a function of Y. The data are a set of Pi, the proportion that a comparison stimulus si is judged discriminable from a standard stimulus So (the method of constant stimuli). An ellipsoid is defined around So such that, if the distance between So and si is evaluated by the radius of the ellipsoid in that direction, then that distance is related to Pi in the form of a sigmoid curve (the cumulative normal distribution). The third axis of the ellipsoid is defined to be parallel with the Y axis and hence there are four free parameters. These parameters are estimated using the principles of either chi-square minimum or maximum likelihood estimation. The algorithm was applied to the data obtained from, respectively, R.M. Rich, D.C. Rich, and Witt and Doring. Results by the present method were compared with their results, which were obtained using different procedures. The method was also applied to the data of Bartleson to test the possibility that the domain of colors called “brown” is ellipsoidal in form; the result was negative. A theoretical discussion on the naure of the sigmoid curve is included.
A wideband high-linearity mixer in 0.5 µm InP DHBT technology

This paper presents the design, implementation and characterization of a wideband down-conversion mixer in a 0.5 µm InP DHBT process. A modified Gilbert cell topology is implemented to improve circuit linearity and to give a means by which DHBT mixers can operate at lower supply voltages. The measured circuit has a maximum conversion gain of 11.3 dB over a 3 dB bandwidth from 7 to 24 GHz. The input referred 1-dB compression point is greater than −15.6 dB across the entire frequency range.
Three-dimensional constitutive equations for Styrene Butadiene Rubber at high strain rates

Abstract Tensile stress–extension ratio and force–extension curves for Styrene Butadiene Rubber dumbbell and sheet specimens, respectively, were obtained from a Charpy tensile impact experiment and used to develop high rate-dependent constitutive equations for the rubber. The tensile tests were performed up to material failure and under constant strain rates ranging from 76 s −1 to 450 s −1 . The rubber became stiffer with increasing strain rate but above 370 s −1 , the stress–extension ratio curve remained almost the same when the extension ratio was greater than 100%. This suggested that the characteristic relaxation time associated with long chain extension was on the order of a few milliseconds. A hyper-viscoelastic constitutive equation was proposed to describe the rate-dependent material behavior of the rubber based on thermodynamics principles. The proposed constitutive equation was implemented in ABAQUS Explicit via a user-defined subroutine and used to predict the tensile impact response of the rubber sheets in the experiments. Numerical predictions for the transient deformation of the rubber sheet using the proposed constitutive equation were within 7% of experimental results.
The Nature and Fundamental Elements of Costs

The historical development of the theory of costs has been away from the disutility analysis of the classicists. — The view that costs are payments for the means of production, arising out of the resistances which they occasion, and set in a competitive price-bidding process, 36. — These resistances resolved into eight scarcity-factors, which are the fundamental elements of costs, 41. — The analysis applied to costs encountered in business enterprise: wages, interest, rents, depreciation, insurance, taxes, and profits. — All can be broken down into the eight elements named 47. — The introduction of monopoly profits into the prices of materials necessitates a distinction between competitive and restrictive costs, 59. — This analysis of costs suggests that an approach to the theory of distribution along similar lines would be fruitful, 62.
Lymphocyte subset differences in patients with chronic fatigue syndrome, multiple sclerosis and major depression

Chronic fatigue syndrome (CFS) is a heterogeneous disorder of unknown aetiology characterized by debilitating fatigue, along with other symptoms, for at least 6 months. Many studies demonstrate probable involvement of the central and autonomic nervous system, as well as a state of generalized immune activation and selective immune dysfunction in patients with CFS. The aim of this study was to compare the lymphocyte subsets of patients with chronic fatigue syndrome to those of patients with major depression and multiple sclerosis as well as those of healthy control subjects. No differences were found in total numbers of T cells, B cells or natural killer (NK) cells. However, differences were found in T, B and NK cell subsets. Patients with major depression had significantly fewer resting T (CD3 + /CD25 - ) cells than the other groups. Patients with major depression also had significantly more CD20 + / CD5 + B cells, a subset associated with the production of autoantibodies. Compared to patients with multiple sclerosis, patients with CFS had greater numbers of CD16 + /CD3 - NK cells. Further study will be required to determine whether these alterations in lymphocyte subsets are directly involved in the pathophysiology of these disorders, or are secondary effects of the causal agent(s).
Water Level and Velocity Characteristics of a Salt Marsh Channel in the Murderkill Estuary, Delaware

ABSTRACT Dzwonkowski, B.; Wong, K.-C., and Ullman, W.J., 2014. Water level and velocity characteristics of a salt marsh channel in the Murderkill estuary, Delaware. High-frequency observations of water level and velocity over one year in Murderkill estuary, a tributary estuary of Delaware Bay, are used to examine changes in tidal and subtidal flow characteristics as water propagates from the mouth of the estuary (Bowers site) into a minor channel that connects to a contiguous salt marsh (channel site), a setting where long-term continuous data sets are uncommon. These data provide insight into the flow behavior in marsh channels, the driving mechanisms of water exchange, and the potential for particle and solute exchange between tidal marshes and their adjacent estuaries. At both sites, tidal forcing is normally the dominant driving mechanism in water level and velocity signals with remote wind forcing having a limited contribution. As the tidal signal propagates from the Bowers site into the salt marsh, ...
Collective Action, City Council Committees, and State Aid to Cities

Studies of city council committee structures offer the potential to shed light both on the dynamics of local politics and on broader theories of legislative organization. Pelissero and Krebs (1997) find that larger councils are more likely to have committee structures and that committees have limited influence on policy outputs, contrary to what distributive models of legislative organization would predict. The author replicates Pelissero and Krebs’s finding on council size but suggests a different interpretation of these results, focusing not on theories of distributive politics but on the collective action dynamics within city councils. Instead of being havens for high-demanding legislators, city council committees are tools with which a council as a whole can more effectively provide collective goods to its city. Finally, the author presents a simple test of whether councils with committees are better able to provide public goods, using state aid as the dependent variable.
Stress: A pervasive dilemma in psychiatric emergency care

This paper (1) identifies a number of broad social-situational forces which have had stress producing impact upon the treatment climate and procedures of the psychiatric emergency setting. (2) describes several of the major effects of these factors both on patients and on the emergency Unlt, (3) applies a person-environment fit (or “mis-fit”) perspective in conceptualizing the stress-related problems illustrated by examination of the repeating patient as a high misfit group and (4) Suggests several recomendations to help increase the “goodness of fit” between the needs, motives and resources of the patient and of the emergency unit and staff E mergency: urgent necessity; sudden or unexpected occurrence requiring prompt attention; crisis state. Psychiatric emergency cases are, quite literally, defined and characterized by urgent need and stressful conditions. The frequently ambiguous, covert, and complicated nature of the psychiatric component renders these crises all the more difficult to manage and to alleviate. Such cases, perhaps more than any other, would best benefit from an environment which fostered a calm, quiet, thorough exploration of the individual’s troubles. The common irony, however, is that the hospital emergency room environment typically operates quite antithetically to this, actually being constituted by a variety of influences which are likely to have a negative impact on patient behavior and patient care.’ The characteristic “charged atmosphere” of the emergency setting is most saliently evident in the pervasive sense of time pressure.? Emergency staff put a high premium on “cool speedy care” which translates into assessment, intervention, and disposition being administered as quickly as possible with minimal disruption.’ While the reasons for this emphasis on speed and brevity are themselves neither trivial nor contrived, the cumulative effect for psychiatric cases is an exacerbation of the patient’s condition,4 a perception by the clinical staff of their work as “onerous and unrewarding,“5 and an overemphasis on overt symptomotology rather than on problem precipitants and dynamics in diagnosis and disposition.0 Furthermore, the problem tends to fuel itself. That is, the greater are the patients’ need states, the more taxed is the limited time resource, the more perfunctory becomes patient care. and the more strained becomes the interpersonal environment for all involved. Thus, not only is the presence and effect of debilitating stress in a variety of forms a common dominator across settings, but across treatment provider and recipient as well. Some of these issues are simply an inherent part of psychiatric emergency care. Evidence indicates, however, that the hospital emergency room as a psychiatric emergency care setting has experienced a rapid and substantial transformation over the past decade and a half. The patchwork approach which has typified efforts to
Combining L1 and L2 methods in the robust stability and performance analysis of nonlinear systems

In this paper, possible benefits of combining the two frameworks in the robust control are discussed. In particular, it is shown that the well-known absolute stability criterion by Zames-Falb (1968) for systems with monotonic nonlinearities (in particular, for systems with saturation) can be improved by using the magnitude bounds derived from the "L1" theory. In conjunction with this result, a lower bound of the Zames-Falb stability margin is derived, by using a duality approach. In the second part of the paper, it is shown how the analysis of the worst case output error magnitude of nonlinear uncertain systems (robust performance in the "L1" setting) can be improved by using the known absolute stability ("L2") techniques.
The concept of stability and systems with constant coefficients

We shall often consider systems of n first order normal differential equations $$\begin{array}{*{20}{c}} {x_i^\prime = {f_i}\left( {t,{x_1}, \ldots ,{x_n}} \right)}&{i = 1,2, \ldots ,n,} \end{array}$$ (1.1.1) where x′ i = dx i /dt and where t is real and f i , x i , real or complex. We shall often denote x = (x 1,..., x n ) as a “point” or a “vector” and t as the “time”, and E n shall denote the space of the points x. Often (1.1.1) is obtained by a transformation of the m second order Lagrange equations relative to a mechanical system with m degrees of freedom, and thus n = 2m.
Surgical management of life threatening events caused by intermittent aortic insufficiency in a native valve: case report

We describe a case of a patient admitted with apparent life threatening events characterized by hypotension and bradycardia. The patient was ultimately found to have intermittent severe aortic insufficiency. Upon surgical exploration, abnormalities were discovered in the aortic valve, which had a small left coronary cusp with absence of the nodulus of Arantius. Following surgical repair of the valve, aimed at preventing the small cusp from becoming stuck in the open position, the patient has remained episode free for over one year.
Classical Control Theory: Design

This chapter considers some standard methods to design controllers. As is the case with design in engineering in general, there are many different ways to do this, but this book is limited to two types. This chapter focuses on lead–lag control. A lead compensator generally enhances the stability of a system and is designed to meet the transient response specifications for the system. A lag compensator generally decreases the steady-state error without significantly altering the transient response characteristics of the system. The previous chapter, by way of introduction to controls, developed the usual rules for design of PID controllers.
STICT model for surface thermodynamics of liquid metal solutions

A new model, called STICT for surface thermodynamics using ideal chemical theory, is developed for the surface tension of liquid metal alloys. It uses the Guggenheim approach to relate surface phase properties to those in the bulk. For strongly solvated metal mixtures, ideal chemical theory is used to characterize bulk properties. The STICT model fits experimental data well for the seven systems for which sufficient data exist. Moreover, calculations of bulk and surface true compositions give some guidance to the tailoring of the surface properties of alloys for various applications.
A REVISION OF THE GENUS ARIGORYTES (HYMENOPTERA: SPHECIDAE: GORYTINI)

Rohwer established the genus Argorytes in 1912 for the reception of Fox's curious, stocky, little southern Californian species Gorytes Coquillettii. In the course of the ensuing thirty-five years, no subsequent investigator has recognized or admitted the validity of Rohwer's distinctive genus. In all probability, however, this is due largely to the relative rarity of the component species. In the past decade I have seen or assembled a number of specimens of this interesting genus and present below a revision of Arigorytes.
Reconstruction of an embedded slab from multifrequency scattered field data under the distorted Born approximation

This paper deals with the inverse scattering problem regarding a loss-less dielectric slab embedded in a loss-less homogeneous half-space starting out from the knowledge of multifrequency scattered field data. The distorted Born approximation of the electromagnetic scattering is assumed and the features of two linear operators, accounting for the electromagnetic scattering and differing on account of the excitation law of the impinging plane wave, are discussed in terms of model error and class of retrievable unknowns by means of singular value decomposition (SVD) analysis. In particular, it is outlined how a suitable choice of the excitation of the impinging wave makes it possible to improve the reconstruction capabilities of the solution algorithm. In addition, the SVD-based solution approach makes it possible to handle the ill-posedness and to regularize the problem. Numerical results confirm the effectiveness of the approach and the theoretical expectations.
Synthesis of Vicinal Aminoalcohols by Stereoselective Aza-Wacker Cyclizations: Access to (−)-Acosamine by Redox Relay†

Diastereoselective aza-Wacker cyclization of O-allyl hemiaminals under aerobic conditions enables efficient access to 1,2-aminoalcohol derivatives from allylic alcohols. The scope of this method is presented and its utility is highlighted in a streamlined synthesis of the biologically important aminosugar (–)-acosamine.
Research Focus: Crust formation in the western United States

Between about 1.8–1.6 Ga, an accretionary belt ~1300 km wide was added to the southern margin of the Archean Wyoming craton. In the prevailing arc-accretion model (Condie, 1982; Karlstrom and Bowring, 1988; 1993), most of this material is considered to be mantle-derived juvenile crust, and therefore represents newly formed crust (at 1.8–1.6 Ga). The interesting and highly provocative paper by Bickford and Hill in this issue of Geology (p. 167–170) challenges the view that crustal growth in southern Laurentia primarily involved accretion of juvenile arc rocks to an Archean core. Although the Bickford and Hill paper focuses specifi cally on Paleoproterozoic crustal evolution of southern Laurentia, it has relevance to mechanisms and rates of crustal formation and growth throughout geologic time. Bickford and Hill present an alternative interpretation for Paleoprotero zoic crustal evolution in which they suggest that signifi cant volumes of older (ca. 1.85 Ga Trans-Hudson/Penokean) crust may be present in southern Laurentia, and that rifting of this crust produced the widespread bimodal volcanic sequences present in the southwestern United States (see also Hill and Bickford, 2001). The principal lines of evidence cited by Bickford and Hill to support their interpretations are the presence of pre-1800 Ma inherited zircons and Nd and Pb isotopic signatures suggestive of older crust, and the abundant rhyolite-dominated bimodal volcanic sequences present in southern Laurentia. In their model, rifting of older crust resulted in basaltic magmatism that provided a heat source for the partial melting of Trans-Hudson/Penokean crust to form the rhyolites. The basaltic component of these bimodal sequences would represent juvenile additions to the crust. The rifting and arc-accretion models are not mutually exclusive.
Infants with swallowing problems

Farah was born at term following spontaneous but prolonged labour, with a difficult forceps delivery. She required resuscitation at birth and developed seizures at 1 hour, resolving at 8 hours of life. Since then she has not required respiratory support but she remains on the Special Care Baby Unit due to difficulties establishing oral feeding. Described as a ‘jittery’ baby, she often appears agitated and distressed. When put to the breast she pushes back and her tone increases. She is unable to latch on for longer than a few seconds before pulling away, coughing and crying. She has a nasogastric tube in situ, and her mother is very upset by Farah’s apparent refusal to feed.
Of Victorianism, Civilizationism, and Progressivism: The Educational Ideas of Anna Julia Cooper and W.E.B. Du Bois, 1892–1940

Anna Julia Cooper and W.E.B. Du Bois were two of the most prominent African-American educators of the late nineteenth and early twentieth centuries. During this period, they both envisioned a broad education tailored specifically to the critical intellectual and vocational needs of the entire black community. They also participated in international affairs, attended and worked together at some of the same conferences and meetings, and shared a belief that education should encourage blacks to place their situation and struggles within a global context. In developing their educational ideas, they both addressed a wide range of educational issues (black women's education, education of the black masses, and the history curriculum in black schools) that spoke to the universal as well as the local realities of black life in America. At the core of their educational thought was their belief that social advancement would result in equality for blacks.
Knee pain diagrams: Correlation with physical examination findings in patients with anterior knee pain

All new patients who presented with knee problems were asked to fill out standard knee pain diagrams before being evaluated. Completed diagrams were not seen by the examining physicians. After obtaining the history and performing the physical examination, one of four physicians marked an identical diagram with the areas of tenderness. Ninety patients with a provisional diagnosis of patellofemoral pain completed 109 (19 bilateral) pain diagrams. Evaluation of the diagrams was quantitated by division of the diagrams into nine zones. The researcher grading the diagrams was blind to whether the diagrams were drawn by the patient or physician. Patients marked an average of 4.23 zones per knee compared with 2.66 zones for physicians. In 88% (96 of 109) of the knees, the physician diagram included all or some of the zones marked by the patients. Eighty-five percent of all zones marked by physicians were included in patient diagrams. Eighty-six percent of negative patient zones correctly predicted a negative examination. Overall frequency of positive findings in each of the nine zones was consistent between patient and physician diagrams. A physician can be confident that findings of tenderness will likely be within zones marked by a patient on a standard diagram of the knee. Pain diagrams facilitate proper diagnosis by correctly directing attention to areas of tenderness in a large percentage of cases and provide an inexpensive and highly useful prediction of areas of anterior knee tenderness in patients with patellofemoral pain.
Enrichment reliability of solid polymer electrolysis for tritium water analysis

We have developed a novel advanced enrichment apparatus for environmental tritium analysis called SPET (Solid Polymer Electrolysis for Tritium Water). It generates no explosive gas, requires no aqueous electrolyte, terminates enrichment rapidly, and the volume reduction is infinite. It has an automatic shutdown system which gives uniform conditions on every run, making the handling and determination of tritium concentrations very easy. The reliability of SPET was studied using environmental concentration standard water and the reproducibility error was found to be within 4%, which is sufficient for environmental measurements.
Magnet Power Supply System for the Isabelle Half-Cell Prototype

Due to stringent requirements on the spatial harmonic content of ISABELLE's magnetic field, the magnet power supplies for the half-cell prototype must be dynamically accurate and stable to within 0.01% of their full-scale rating. Depending on the application, the full-scale current of various units comprising the system ranges from ± 50 A to 4000 A. The system, as constructed is fully controllable and programmable either manually or with a control computer.
Novel activation of araC expression and a DNA site required for araC autoregulation in Escherichia coli B/r.

Mutations in the araC gene have been isolated which alter both the activator and autoregulatory functions of AraC protein (L.G. Cass and G. Wilcox, J. Bacteriol. 166:892-900, 1986). In this study, the effect of each araC mutation on autoregulation was characterized in vivo and in vitro in the presence of L-arabinose. The effect of L-arabinose in some of these araC mutants revealed a novel activation of araC expression which was not observed in the araC+ cell. Experiments were therefore focused on understanding the mechanism of this novel activation. We describe a systematic analysis of the effect of mutations within the known regulatory binding sites for araBAD and araC transcription on araC expression. Our results suggest that the novel activation of araC expression requires the AraC activator-binding site, araI, and the cyclic AMP receptor protein-cyclic AMP complex-binding site. We also found that in the absence of L-arabinose, the araI site was required for maximal autoregulation by the wild-type AraC protein.
Do Tropical Storm Regimes Influence the Structure of Tropical Lowland Rain Forests

It has been suggested that the average canopy height of Madagascar's lowland rain forests is shorter and the average tree density is greater than in other tropical lowland rain forests of the world. The cause was hypothesized to be frequent cyclone disturbances. We compared the structure of the lowland rain forests in Madagascar to the structure described in published accounts of other tropical lowland rain forests. We found that the eastern coastal lowland forests of Madagascar have short canopy heights relative to that of many other lowland tropical rain forests, and that these Malagasy forests also have relatively high tree densities. On a worldwide basis, there is a significant correlation between short forest canopies and occurrence of tropical cyclones. The association between high tree density and occurrence of tropical cyclones is valid for Africa, but the pattern does not hold up globally.
Aggregate particles in the plumes of Enceladus

Estimates of the total particulate mass of the plumes of Enceladus are important to constrain theories of particle formation and transport at the surface and interior of the satellite. We revisit the calculations of Ingersoll and Ewald (Ingersoll, A.P., Ewald, S.P. [2011]. Icarus 216(2), 492–506), who estimated the particulate mass of the Enceladus plumes from strongly forward scattered light in Cassini ISS images. We model the plume as a combination of spherical particles and irregular aggregates resulting from the coagulation of spherical monomers, the latter of which allows for plumes of lower particulate mass. Though a continuum of solutions are permitted by the model, the best fits to the ISS data consist either of low mass plumes composed entirely of small aggregates or high mass plumes composed of mostly spheres. The high particulate mass plumes have total particulate masses of (166 ± 42) × 10^3 kg, consistent with the results of Ingersoll and Ewald (Ingersoll, A.P., Ewald, S.P. [2011]. Icarus 216(2), 492–506). The low particulate mass plumes have masses of (25 ± 4) × 10^3 kg, leading to a solid to vapor mass ratio of 0.07 ± 0.01 for the plume. If indeed the plumes are made of such aggregates, then a vapor-based origin for the plume particles cannot be ruled out. Finally, we show that the residence time of the monomers inside the plume vents is sufficiently long for Brownian coagulation to form the aggregates before they are ejected to space.
A preliminary report on a new laparoscopic sterilization approach: the silicone rubber band technique.

Abstract A preliminary report is given of a new laparoscopic sterilization approach with the use of silicone rubber bands. A description of the laparoscope silicone rubber band applicator, as well as its operative utilization, is provided. One hundred cases have been completed without any major problems. No statement can be made at this time as to the incidence of failure. The described technique eliminates the need for the thermoenergy which is used in tubal occlusion and thus removes the cause of intestinal burns. The potential for successful future tubal reopening procedures should be greater with this procedure.
Duo Duo: An Impossible Farewell, or, Exile between Revolution and Modernism

Early in the year 1989, Duo Duo was invited to go to England to give poetry readings; this trip, his first to the West, was scheduled on June 4. It turned out that Duo Duo spent the eve of his departure on Tiananmen Square and witnessed another turn of twentieth-century Chinese history, an event that in the future would be known as June Fourth. Upon his arrival in England, he found himself, all of a sudden, the focus of Western media attention, and his identity that of a dissident poet. Soon after, he, like so many fellow members of the so-called Misty Poetry generation, such as Bei Dao, Gu Cheng, and Yang Lian, became a poet in exile, and rose from relative obscurity to international fame.