cssi/SciSciGPT-SciSciNet huggingface dataset:
Rates and Timing of Earth Surface Processes From In Situ-Produced Cosmogenic Be-10

Beryllium-10 is the longest-lived of the seven known unstable isotopes of Be; it results mostly from the interaction of cosmic radiation, primarily neutrons, with a variety of target atoms by spallation, the splitting of nuclei (Lal 1988). It can also be produced at very low levels by radio-disintegration of U and Th (Sharma and Middleton 1989). Although all radioactive Be isotopes are produced in the atmosphere via cosmic-ray reactions (Arnold 1956; Lal and Peters 1967; Morris et al., Chapter 5, this volume), in this paper, we are most interested in 10Be produced in rock, which we refer to as in situ -produced. Such in situ -produced 10Be is a cosmic-ray dosimeter functioning as a quantitative monitor of near-surface residence time. In some geologic situations, 10Be can be used as a chronometer, allowing one to estimate the duration of surface exposure. In other settings, 10Be can be used as a tracer allowing one to estimate the rate, distribution, and behavior of Earth surface processes. Rates of 10Be production are very low in rocks exposed at Earth’s surface, 102 atoms g−1 y−1 resulting in typical in situ -produced 10Be concentrations, termed activities, of 103 to 107 atoms g−1. The development of accelerator mass spectrometry (AMS) in the 1980s allowed routine measurement of 10Be at levels typical of rocks exposed near Earth’s surface (Elmore and Phillips 1987). Analytical refinements in the 1990s lowered detection limits by an order of magnitude, allowing dating of exposure periods <<103 years in favorable geologic and geographic situations (simple exposure histories at high altitude and latitude). Most in situ 10Be is measured in quartz mineral separates where the primary spallation target is O (Lal and Arnold 1985 …
Neurological Impairment Following Myocardial Ischemia Associated with Postoperative Epidural Analgesia

Although epidural analgesia reduces the postoperative stress response and provides good pain relief for patients, potential complications associated with the technique may decrease its acceptability for some patients. We describe a 76-year-old female who underwent surgery for carcinoma of the urinary tract. Postoperative epidural analgesia was performed at the postanesthesia care unit. Neither a repeat attempt nor accidental dural puncture was encountered during the procedure. Unfortunately, she sustained neurological impairment of the bilateral lower limbs following an episode of myocardial ischemia during the early postoperative period. When the neurological deficit was recognized following epidural anesthesia, poor puncture technique was the first to be blamed. In fact, a high level of sensory blockade could markedly decrease blood pressure and heart rate, particularly in the presence of hypovolemia, which might lead to impairment of coronary perfusion and result in my ocardial ischemia. Severe systemic hypotension might further lead to hypoperfusion of the spinal cord, most possibly in the mid-thoracic region (T4 to T8) due largely to its relative hypovascularity. Therefore, we recommend that maintaining sufficient circulatory volume of the patient, evaluating and recording the neurological function of the patient and determining the possible risk factors associated with coronary arterial disease are imperative prior to performing an epidural procedure.
Inflammation of the external eye

The pathophysiology and therapeutic approaches currently in use for inflammation of the external eye are discussed in detail. The general principles of inflammation are explained in detail as well as their specific application to the external ocular tissues.
Performance Excellence Movement Observation: What to Watch … and Why

(1993). Performance Excellence Movement Observation: What to Watch … and Why. Strategies: Vol. 7, No. 2, pp. 17-19.
An adaptive control algorithm for parameter adjustments

This paper is concerned with making on-line adjustments in the adjustable parameters of a feedback control system in order to compensate for a deterioration of performance brought about by unknown variations in other system parameters. The algorithms to be discussed here are extensions and modifications of an algorithm reported in [1] and [2]. The basic control system containing known, adjustable and unknown parameters is assumed to be represented by the vector equations x = A(?, ?)x + B(?, ?)r (1) y = Cx The n-vector x(t) is the state of the over-all basic (feedback) control system, r(t) is a p-vector of arbitrary command and disturbance inputs, and y(t) is a q-vector of output variables. The coefficient matrices A and B in (1) are given functions of a vector ? = (?1, .. ?a) of adjustable controller parameters (adjustable amplifier gains, filter time constants and the like) and a vector ? = (?1, .. ?b) of plant parameters. The value of ? is assumed to be unknown and may be slowly varying with time.
Dynamic shear banding: A three-dimensional analysis

Abstract The three-dimensional (3D) aspects of localized deformations and shear banding under dynamic loading conditions and in both elastoviscoplastic and thermoviscoplastic materials are investigated. It is shown that the rate-dependent constitutive models considered that exhibit a net softening response, along with standard eight-node brick finite elements with one integration point (piece-wise constant strain and stress fields), produce sharp localized deformation zones without recourse to any special mesh design. This, in turn, allows for the numerical prediction of the shear band angle. The 3D results are illustrated for the development of shear bands in uniaxial extension of specimens with different thicknesses. It is shown that the 3D geometric aspects have considerable effects on the development of the shear band and its evolution. By examining the behavior of the kinetic energy, a localization criterion is also developed.
Microradiographic and electron microscopic observations of the enamel-covered dentine in rat molars

The enamel-covered primary and secondary coronal dentine in the molars of 90-day-old and 360-day-old rats was examined using microradiography. Some preparations were subsequently examined by transmission and scanning electron microscopy (SEM). Fractured dentine surfaces and methacrylate casts of the tubular system in the primary dentine were also examined with SEM. No microradiographic evidence of a hypermineralized peritubular matrix, such as that seen in man and other species, was seen in either young or old rats. Transmission and SEM confirmed the microradiographic findings. The tubule obliteration and extensive intra-luminal mineral deposits which have been reported in the enamel-free coronal dentine of the rat molar were not seen in the enamel-covered coronal dentine but some evidence of tubule obliteration was seen in the secondary dentine.
A review of steric interactions of ions: Why some theories succeed and others fail to account for ion size

As nanofluidic devices become smaller and their surface charges become larger, the steric interactions of ions in the electrical double layers at the device walls will become more important. The ions’ size prevents them from overlapping, and the resulting correlations between the ions can produce oscillations in the density profiles. Because device properties are determined by the structure of these double layers, it is more important than ever that theories correctly include steric interactions between ions. This review analyzes what features a theory must have in order to accurately account for steric interactions. It also reviews several popular theories and compares them against Monte Carlo simulations to gauge their accuracy. Successful theories of steric interactions satisfy the contact density theorem of statistical mechanics and use locally averaged concentrations. Theories that do not satisfy these criteria, especially those that use local concentrations (instead of averaged concentrations) to limit local packing fraction, produce qualitatively incorrect double layer structure. For which ion sizes, ion concentrations, and surface charges monovalent ions steric effects are important is also analyzed.
Systematics of Soft Final State Interactions in B Decays.

By using very general and well established features of soft strong interactions we show, contrary to conventional expectations, that (i) soft final state interactions (FSI) do not disappear for large {ital m}{sub {ital B}}, (ii) inelastic rescattering is expected to be the main source of soft FSI phases, and (iii) FSI which interchange charge and/or flavors are suppressed by a power of {ital m}{sub {ital B}}, but are quite likely to be significant at {ital m}{sub {ital B}}{approx_equal}5 GeV. We briefly discuss the influence of these interactions on tests of {ital CP} violation and on theoretical calculations of weak decays. {copyright} {ital 1996 The American Physical Society.}
Comparison of dissolution rates of different crystalline phases of fluprednisolone by in vitro and in vivo methods

The in vitro dissolution rates of six crystalline phases of fluprednisolone were determined and compared with in vivo dissolution rates from pellet implants in rats. The dissolution studies were correlated with animal weight loss and adrenal gland atrophy. Excellent correlations were obtained between the in vitro and in vivo dissolution rates; however, correlation with animal weight loss and adrenal gland atrophy was only fair.
Click-xylosides mitigate glioma cell invasion in vitro

Tumor related invasion allows cancers to spread beyond tissue boundaries and significantly affects patient prognosis. In this study we show that several click-xylosides markedly inhibit the invasive capability of a highly invasive glioma cell line in vitro. These novel xylosides are promising chemical biology tools to probe the role of the proteoglycan glycome in regulating tumor biology.
Barbituric Acid Initiated Rearrangement of 2,2′-Pyridil into 5,5′-(2-pyrilidine)bisbarbituric Acid.

[reaction: see text] In the study of the barbituric acid initiated 2,2'-pyridil rearrangement, a very efficient synthetic procedure (isolated yield 80-90%) for the preparation of useful 2-pyrilidenes 3 was developed.
Receptor-independent Protein Kinase Cα (PKCα) Signaling by Calpain-generated Free Catalytic Domains Induces HDAC5 Nuclear Export and Regulates Cardiac Transcription

Receptor-mediated activation of protein kinase (PK) C is a central pathway regulating cell growth, homeostasis, and programmed death. Recently, we showed that calpain-mediated proteolytic processing of PKCα in ischemic myocardium activates PKC signaling in a receptor-independent manner by releasing a persistent and constitutively active free catalytic fragment, PKCα-CT. This unregulated kinase provokes cardiomyopathy, but the mechanisms remain unclear. Here, we demonstrate that PKCα-CT is a potent regulator of pathological cardiac gene expression. PKCα-CT constitutively localizes to nuclei and directly promotes nucleo-cytoplasmic shuttling of HDAC5, inducing expression of apoptosis and other deleterious genes. Whereas PKD activation is required for HDAC5 nuclear export induced by unprocessed PKCs activated by phorbol ester, PKCα-CT directly drives HDAC cytosolic relocalization. Activation of MEF2-dependent inflammatory pathway genes by PKCα-CT can induce a cell-autonomous transcriptional response that mimics, but anticipates, actual inflammation. Because calpain-mediated processing of PKC isoforms occurs in many tissues wherein calcium is increased by stress or injury, our observation that the catalytically active product of this interaction is a constitutively active transcriptional regulator has broad ramifications for understanding and preventing the pathological transcriptional stress response.
Phenology of Four Chaoborus Species

The phenology of four Chaoborus species in four bog lakes in the upper peninsula of Michigan was documented. The sequence timing of pupation was: Chaoborus americanus , early May; C. flavicans , end of May; C. punctipennis , early July; C. trivittatus , end of August and early September. C. americanus , C. punctipennis , and C. trivittatus each occurred in two of the lakes. Differences in the timing of pupation for each of these species between lakes were not always correlated with environmental differences between lakes. C. punctipennis , C. flavicans , and one of the C. americanus populations was univoltine. The other C. americanus population may have been bivoltine. One C. trivittatus population appeared to be univoltine, whereas the other may have had a 2-year generation time. The significance of the sequence and timing of pupation of these species is discussed in relation to seasonality, interspecific competition, and predation.
Leakpoint pressures in female stress urinary incontinence

Patient selection is critical to achieving good results in the surgical management of stress urinary incontinence. The evaluation of urethral function in these women is of great importance, since the choice of operative technique often depends on the ability of the urethra to generate adequate resistance to the explusive forces of increased abdominal pressure. The Valsalva leakpoint pressure (VLPP) has been described as an easily performed, reproducible and accurate urodynamic test to assess the patient for the presence of intrinsic sphincter deficiency (ISD). Critical review of the VLPP demonstrates its reproducibility and correlation with other measures of ISD. However, more work needs to be done to identify the truly critical values of VLPP that would help in selecting the most appropriate procedure in surgery for stress incontinence.
Continental thermal isostasy: 1. Methods and sensitivity

[1] Continental elevations result from a combination of compositional and thermal buoyancy and geodynamic forces. Thermal effects are often masked by compositional variations to crustal density and thickness that produce equal or greater relief. We have developed a method by which compositional variations in the crust may be removed, thereby isolating the thermal contribution to elevation. This isostatic correction normalizes the composition of a region to a standard crustal column 39 km thick having an average density of 2850 kg m−3. The crustal thickness and density are computed using one-dimensional seismic VP models and an empirical velocity to density conversion. Continental regions adjusted for compositional effects show that thermal isostasy can produce nearly 3 km of relief between cold shield platforms and hot rift zones, comparable to observed relief between young (hot) and old (cold) regions of oceanic lithosphere. A Monte Carlo analysis is used to estimate the uncertainties in the isostatic correction. Uncertainties in the seismic parameters, surface heat flow, and regression coefficients of the velocity-density relationship are all incorporated into the analysis. The Wyoming Craton is used as a case study to demonstrate the effectiveness of the elevation adjustment. Analyses of seismic VP models yield a crustal thickness of 49.5 ± 4.9 km and density of 2945 ± 13 kg m−3. The computed compositional correction to elevation for the Wyoming Craton is −131 ± 180 m, shifting the raw elevation of 1069 m to an adjusted elevation of 938 m.
A study of the perturbations between the A1Σ+u and b3Πu states of Na2

Abstract The interaction between the A1Σ+u and b3ΠΩu states of Na2 is explored by resonantly exciting A states via A-X transitions and, after an adjustable delay time, photoionizing them. For long delays signals arise only from states with significant fractions of both A and b state character. Thus the regions where the interaction is important stand out clearly in the spectrum. Using this technique we have investigated perturbations of the A v' = 3, 7 and 8 states by the b v' = 10, 13 and 14 states.
New approaches to developing antimicrobials for resistant bacteria

Few medical advances in the twentieth century which we have just completed have had as much potential to change the health of the world’s population as the discovery and clinical application of antibacterial agents. These agents were truly “miracle drugs” and they made it possible to treat a whole series of diseases that formerly were universally fatal or produced a heavy toll of morbidity. The list of such infections that threatened the human race in the preantibiotic era included a variety of venereal diseases, such as syphilis and gonorrhea, as well as pneumococcal pneumonia, tuberculosis, typhoid fever, bubonic plague, and a host of other diseases. The initial antimicrobial agents were discovered by scientists in Germany (arsphenamine and the sulfonamides) and the United Kingdom (penicillin). Subsequently a great deal of work on the discovery of new antimicrobial agents was carried out in the United States and Japan. Indeed, the Japanese contribution to the discovery of new antimicrobial agents is truly remarkable. There are more than 117 useful antibiotics and related agents that have been discovered by Japanese scientists and, of these, 41 agents have been licensed for clinical use throughout the world. The luster of this discovery has been tarnished over the ensuing years by the progressive development of resistance in multiple species of bacteria. Because of this, as we enter the twenty-first century there is again a major need for new antibacterial agents. At the same time, the number of new agents being developed for clinical use has been progressively decreasing. There are several key reasons for the recent decline in the number of newly marketed antimicrobial agents. In the first place, most of the easy targets allowing selective toxicity for antimicrobials have been discovered. Moreover, it is increasingly costly to bring a new antimicrobial agent to the market. It is currently estimated that the average cost to develop a new prescription drug from the discovery phase to active marketing of the drug is
The influence of nearby earthed objects and of the polarity of the voltage on the direct-voltage breakdown of horizontal sphere-gaps

Experiments were made to determine, the influence of nearby earthed objects on the breakdown voltages of 6.25 and 12.5cm-diameter sphere-gaps. The effect was found to be a function of both gap length and sphere diameter. A method has been discussed for establishing clearances which are suitable for use when the sphere-gaps are employed for accurate voltage measurements. Recommended clearances have been quoted which are suitable for all sizes of spheres, and a distinction has been made between the clearance conditions required for experimental calibrations of the breakdown voltages, and those required when a calibrated gap is used for the measurement of voltage. The polarity of the direct voltage had only a small influence on the breakdown voltages of the gaps.
Covalent binding of prostaglandins G2 and H2 to components of ram seminal vesicle microsomal fraction.

Abstract Following incubation of 1- 14 C arachidonic acid with a microsomal preparation of ram seminal vesicles, 90 per cent of the products formed were classical prostaglandins and hydroxyfatty acid. In addition, approximately 8 per cent of the products formed possessed radioactivity which was covalently bound to the microsomal pellet after acid precipitation and solvent extraction. The amount of covalently bound material derived from arachidonate was related to the concentration of free prostaglandin (PG) endoperoxides in the incubation mixture, indicating that these reactive intermediates were probably responsible for the generation of the covalently bound material. Protein-associated radioactivity was also observed following incubation of ¦ 1- 14 C ¦PGG 2 or ¦ 1- 14 C ¦PGH 2 with a heat-denatured preparation of ram seminal vesicle microsomes. Such preparations do not convert PGG 2 to PGH 2 ; thus, the binding of PGG 2 was not due to its prior conversion to PGH 2 . The rate constant for the covalent binding of PGG 2 (0.19 min −1 ) was approximately twice that for PGH 2 (0.11 min −1 ), suggesting that both 9, 11-endoperoxy and 15-hydroperoxy groups participate in the binding reaction. Moreover, the rate constant of binding derived from arachidonate (0.12 min −1 ) approximated those of the purified endoperoxides. In an active microsomal preparation, glutathione reduced covalent binding and increased PGE 2 formation without greatly affecting oxygen consumption and, therefore, without affecting total product formation from arachidonic acid. Glutathione, therefore, probably inhibited covalent binding by lowering free endoperoxide concentrations in the incubation mixture. Diethyldithiocarbamate and phenylbutazone, but not para-aminophenol or butylated hydroxyanisole, inhibited the covalent binding of PGG 2 to heat-denatured tissue protein. These results suggest that the covalent binding reaction may proceed via the formation of free radicals.
Effects of naturally-occuring nontraumatic separations from mother

Thirty-three twelve-month-old infants were divided into three groups based on the frequency and length of naturally-occurring nontraumatic separations from mother during the first year. One group had experienced only brief separations when left with a babysitter for an evening. A second group had been left once or twice for an average of five days while parents vacationed. A third group had been left regularly and frequently during the daytime, usually because mother was working. These groups were compared on measures of reaction to separation and reunion, in the home and in the laboratory, at one year of age. No group differences were found on any of the dependent variables. It is suggested that the quality of substitute care is probably more important than separation per se in mediating the impact of employment or daycare on infant development.
Microdialysis sampling combined with electron spin resonance for superoxide radical detection in microliter samples.

Quantitation of superoxide radical (O2•-) production at the site of radical generation remains challenging. Microdialysis sampling is an advantageous tool for sampling from localized environments. It is difficult to combine electron spin resonance (ESR) spin traps with microdialysis because O2•- adducts with common nitrone spin traps have shorter half-lives than typical microdialysis collection times. Furthermore, typical dialysate samples (5−15 μL) suffer significant sensitivity loss when diluted for detection in a conventional ESR flat cell (200 μL). To overcome these difficulties, a cyclic hydroxylamine, 1-hydroxy-4-phosphonooxy-2,2,6,6-tetramethylpiperidine (PP−H), which produces a stable nitroxide radical (PP•) product upon reaction with O2•- was employed. Capillary cells (1.4 μL effective volume) coupled with a loop−gap resonator were utilized to measure PP• in microliter microdialysis samples (LOD 0.36 pmol). A xanthine/xanthine oxidase (X/XO) model system provided sustained O2•- production. When P...
Metamorphosed Plio-Pleistocene evaporites and the origins of hypersaline brines in the Salton Sea geothermal system, California: Fluid inclusion evidence

Abstract The Salton Sea geothermal system (SSGS) occurs in Plio-Pleistocene deltaic-lacustrine-evaporite sediments deposited in the Salton Trough, an active continental rift zone. Temperatures up to 365°C and hypersaline brines with up to 26 wt.% TDS are encountered at 1–3 km depth in the sediments, which are undergoing active greenschist facies hydrothermal metamorphism. Previous models for the origins of the Na-Ca-K-Cl brines have assumed that the high salinities were derived mainly from the downward percolation of cold, dense brines formed by low-temperature dissolution of shallow non-marine evaporites. New drillcores from the central part of the geothermal field contain metamorphosed, bedded evaporites at 1 km depth consisting largely of hornfelsic anhydrite interbedded with anhydrite-cemented solution-collapse shale breccias. Fluid inclusions trapped within the bedded and breccia-cementing anhydrite homogenize at 300°C (identical to the measured downhole temperature) and contain saline Na-Ca-K-Cl brines. Some of the inclusions contain up to 50 vol.% halite, sylvite and carbonate crystals at room temperature, and some halite crystals persist to above 300°C upon laboratory heating. The data are consistent with the trapping of halite-saturated Na-Ca-K-Cl fluids during hydrothermal metamorphism of the evaporites and accompanying solution collapse of interbedded shales. We conclude that many of the salt crystals in inclusions are the residuum of bedded evaporitic salt that was dissolved during metamorphism by heated connate fluids. Therefore, the high salinities of the Salton Sea geothermal brines are derived in part from the in situ hydrothermal metamorphism and dissolution of halides and CaSO 4 from relatively deeply-buried lacustrine evaporites. This fact places important constraints on modeling fluid-flow in the SSGS, as brines need not have migrated over great distances. The brines have been further modified to their present complex Na-Ca-K-Fe-Mn-Cl compositions by on-going sediment metamorphism and water-rock interaction.
Polymorphonuclear leukocytes and monocytes/macrophages in the pathogenesis of cerebral ischemia and stroke.

The extent to which polymorphonuclear leukocytes and monocytes/macrophages contribute to the pathobiology of cerebral ischemia and stroke is an issue of long-standing contradiction and controversy. Recent developments in the ability to selectively modify leukocyte adhesion with antiadhesion antibodies and the potential clinical application of this therapeutic approach have spurred a resurgence of experimental studies examining the role of leukocytes in cerebral ischemia and stroke.We review studies examining leukocyte accumulation, initiation of thrombosis, and exacerbation of ischemic brain injury in stroke, and we examine other proposed contributions of leukocytes to cerebrovascular pathophysiology.The importance of specific characteristics of a given ischemia model and of underlying stroke risk factors in determining the degree of leukocyte involvement and effectiveness of therapies directed against these cells is discussed.
Performance Evaluation of a Multicore System with Optically Connected Memory Modules

Over the past years, there have been impressive advances in bandwidth, latency, and scalability of on-chip networks. However, unless the off-chip network bandwidth and latency are also improved, we might have unbalanced systems which will limit the improvements to overall system performance. In this paper, we show how dense wavelength-division multiplexing (DWDM) -based optical interconnects could be used to emulate multiple buses in a fully-buffered DIMM (FB-DIMM) -like memory system to improve both bandwidth and latency. We evaluate an optically connected memory using full-system simulations of an 8-core system running memory-intensive multithreaded workloads. We show that for the FFT benchmark, optically connected memory can reduce the average memory request latency by 29% compared to a single-channel DDR3 SDRAM system and provide an overall performance speedup of 1.20. We also show that at least two DDR3 memory channels are needed to match the performance of a single optical bus, which demonstrates the advantage of optical interconnects in terms of savings in the number of pins required.
Retrieval-induced forgetting: evidence for a recall-specific mechanism.

Previous work has shown that recalling information from long-term memory can impair the long-term retention of related representations—a phenomenon known as retrieval-induced forgetting (Anderson, Bjork, & Bjork, 1994). We report an experiment in which the question of whether retrieval is necessary to induce this form of impairment was examined. All the subjects studied six members from each of eight taxonomic categories (e.g.,fruit orange). In the competitive practice condition, the subjects practiced recalling three of the six members, using category-stem cues (e.g.,fruit or____). In the noncompetitive practice condition, the subjects were reexposed to these same members for the same number of repetitions but were asked to recall the category name by using the exemplar and a stem as cues (e.g.,fr____orange). Despite significant and comparable facilitation of practiced items in both conditions, only the competitive practice subjects were impaired in their ability to recall the nonpracticed members on a delayed cued-recall test. These findings argue that retrieval-induced forgetting is not caused by increased competition arising from the strengthening of practiced items, but by inhibitory processes specific to the situation of recall.
First-Passage-Time Prototypes for Precipitation Statistics

AbstractPrototype models are presented for time series statistics of precipitation and column water vapor. In these models, precipitation events begin when the water vapor reaches a threshold value and end when it reaches a slightly lower threshold value, as motivated by recent observational and modeling studies. Using a stochastic forcing to parameterize moisture sources and sinks, this dynamics of reaching a threshold is a first-passage-time problem that can be solved analytically. Exact statistics are presented for precipitation event sizes and durations, for which the model predicts a probability density function (pdf) with a power law with exponent −. The range of power-law scaling extends from a characteristic small-event size to a characteristic large-event size, both of which are given explicitly in terms of the precipitation rate and water vapor variability. Outside this range, exponential scaling of event-size probability is shown. Furthermore, other statistics can be computed analytically, incl...
“A Strange Incongruity”: The Imaginary India of the International Exhibitions

Consider the Gwalior gateway, the “elegant stone archway,” as the Illustrated London News put it, that “forms a noble entrance to the [Indian] Palace” at South Kensington's Colonial and Indian Exhi...
Virtual Reality: Real Promises and False Expectations

Abstract The article examines the latest development in advanced computer‐graphics termed Virtual Reality (VR), which is a technology that entails a 3‐dimensional artificial environment in which the user perceives a sense of presence. The paper discusses the dilemma of defining VR, and the limitations of the current technology. Furthermore, the author describes his experience with VR and looks at the implications of this new technology for education.
The U.S. fast reactor materials and structures program

Materials and structures problems are central to many critical issues concerning the economic competitiveness, reliable performance, and safety of liquid metal fast breeder reactor (LMFBR) power plants.
Inhibition of membrane phosphotyrosyl-protein phosphatase activity by vanadate.

Abstract We have investigated the effect of vanadate on the phosphoserine- and phosphotyrosine-specific phosphoprotein phosphatase activities of A-431 cell membranes and have found that micromolar concentrations of vanadate strongly inhibit the membrane-dependent dephosphorylation of histones containing phosphotyrosine but that they do not inhibit the dephosphorylation of histones containing phosphoserine and phosphothreonine. In addition, the dephosphorylation of endogeneous membrane proteins of A-431 cells (which are known to be phosphorylated at tyrosine residues) was inhibited by vanadate. These results show that vanadate is a potent and selective inhibitor of phosphotyrosyl-protein phosphatase.
Student narratives and the hidden curriculum in the surgery clerkship.

As a current trainee at a medical school that is undergoing curricular reform, I think the recent article by Rogers and colleagues 1 offers important ideas about how to integrate issues of professionalism into the surgery clerkship curriculum. One particularly productive use of the students’ narratives was the identification of perceived lapses in professional behavior as a starting point for discussion and reflection among students and within student-faculty mentorships. Similar methods have been employed to focus attention on medical errors in the context of professionalism during the surgery clerkship. 2 One theme that has emerged from the active discussions on professionalism at my institution is that trainees’ preparedness for clinical practice does not rest solely on recognizing appropriate behavior of the self. A foundational understanding of others, which includes issues surrounding communication and diversity, appears fundamental to many competencies in the surgical sciences and to optimal patient care. Methods for integrating cultural competency training in surgical education have been debated and discussed in these pages, most recently by Butler and colleagues, who proposed a vignette-based clerkship curriculum 3 that spans students’ experiences in the operating room and on the wards. Student narratives may also have a role in propelling this framework by grounding discussions in reallife, real-time experiences that can address lapses in professional behavior. The surgery clerkship at Yale 4 includes a narrative reflection assignment centered on caring for surgical patients from different backgrounds and traditions. These essays have helped to articulate aspects of the hidden curriculum that my colleagues and I, as well as our faculty mentors in surgery, may not have otherwise had a formal opportunity to explore. 5 Both positive and negative examples of behavior can be made explicit in these narratives, which have then fueled spirited discussions about respecting patient autonomy, challenging the sociocultural origins of differential outcomes, or recognizing faith traditions when they conflict with the standard of care. Similar to the findings of Rogers and colleagues, these narratives have shed light on elements of the culture of surgery that often go unnoticed in the routine business of clinical care. Increased recognition of the role and influence of the hidden curriculum in shaping professional identities has driven new approaches to leveraging trainees’ observations as teaching opportunities. Surgery clerkship directors are not alone in trying new methods; clerkships in other specialties have also grappled with these challenges. 6,7 As best practices in the surgery clerkship are tested and shared, I am encouraged by the growing evidence that written narratives can help to probe and address the many facets of the hidden curriculum in surgery. During this period of curricular reform, I hope that both students and clerkship leaders can collaborate on innovative strategies that illuminate these vital areas of surgical education.
Wave Propagation in Two-Dimensional Nonlinear Periodic Lattices

This paper investigates wave propagation in two-dimensional nonlinear periodic structures subject to point harmonic forcing. The infinite lattice is modeled as a springmass system consisting of linear and cubic-nonlinear stiffness. The effects of nonlinearity on harmonic wave propagation are analytically predicted using a novel perturbation approach. Response is characterized by group velocity contours (derived from phase-constant contours) functionally dependent on excitation amplitude and the nonlinear stiffness coefficients. Within the pass band there is a frequency band termed the “caustic band” where the response is characterized by the appearance of low amplitude regions or “dead zones.” For a two-dimensional lattice having asymmetric nonlinearity, it is shown that these caustic bands are dependent on the excitation amplitude, unlike in corresponding linear models. The analytical predictions obtained are verified via comparisons to responses generated using a time-domain simulation of a finite two-dimensional nonlinear lattice. Lastly, the study demonstrates amplitude-dependent wave beaming in two-dimensional nonlinear periodic structures.Copyright © 2009 by ASME
Some simple boundary value problems with corner singularities and boundary layers

Some boundary value problems for a second-order elliptic partial differential equation in a polygonal domain are considered. The highest order terms in the equation are multiplied by a small parameter, leading to a singularly perturbed problem. The singular perturbation causes boundary layers and interior layers in the solution, and the corners of the polygon cause corner singularities in the solution. The paper considers pointwise bounds for derivatives of the solution that show the influence of these layers and corner singularities. Several recent results on this problem are surveyed, and some open problems are stated and discussed.
I’m sorry about the rain! Superfluous apologies demonstrate empathic concern and increase trust.

Existing apology research has conceptualized apologies as a device to rebuild relationships following a transgression. Individuals, however, often apologize for circumstances for which they are obv...
An atheistic sense to Stanley Hauerwas’s theology

This essay argues that Stanley Hauerwas’ Christian ethics exemplifies a manner of speech that does not premise divine activity as necessary for theological judgment. An anti-constantinian reticence regarding divine activity sits at the heart of Hauerwas’ work, giving it an atheistic sense emblematic of secularized cultural conditions, marking his theology as decidedly baptist. The essay takes the form of a sustained engagement with Nicholas Healy’s incisive critique that Hauerwas disastrously joins together what should remain apart, what David Kelsey distinguishes as logics of belief and logics of coming to belief. After passing on a defensive response to Healy, the article advances a constructive response that would have theological speech take up residence between logics of belief and coming to belief, which the article re-imagines in terms of what Stanley Cavell calls “comedies of remarriage.”
Gibbs-Bogoliubov variational principle for Born-Oppenheimer systems.

A form of the Gibbs-Bogoliubov statistical-mechanical variational principle is enunciated that is well adapted to systems in which the electrons are treated quantum mechanically but the nuclei may be treated classically. An initial variational solution for fixed nuclear positions yields a statistical Born-Oppenheimer potential that serves as input for a variational evaluation of the nuclear configurational free energy.
Reactions involving selenium metal as an electrophile. 2. A general procedure for the preparation of unsaturated β-dicarbonyl compounds

Abstract A variety of β-dicarbonyl compounds can be converted to the corresponding unsaturated derivatives in high yields. The process involves reaction of the β-dicarbonyl carbanion with Se metal, followed by alkylation with methyl iodide to form the methylseleno derivative and subsequent oxidative elimination.
A plasmonic switch based on molecular machine-Au nanodisk complexes

A plasmonic switch is demonstrated with rotaxane-derivatized Au nanodisks. The molecule-nanodisk complexes exhibit redox-controlled reversible plasmon-based switching, suggesting that nanoscale movement with surface-bound molecular machines can be used as the active components of plasmonic devices.
Response to Letters Regarding Article, “Perioperative Dexmedetomidine Improves Outcomes of Cardiac Surgery”

We thank Hyder and colleagues for their careful, insightful reviews and thoughtful comments on our study that demonstrated that perioperative dexmedetomidine use is associated with better outcomes after cardiac surgery.1 We reported on the impact of a dexmedetomidine infusion started in the operating room after patients were separated from cardiopulmonary bypass. Because this was a retrospective, single-center study, all of the patients in both groups were managed in a similar fashion throughout the perioperative period. Intraoperative anesthesia management was consistent among our cardiac anesthesiologists, with an institutional standard of a moderate dose of narcotic (fentanyl or sufentanil) supplemented by a volatile anesthetic agent. Similarly, postoperative sedation in the intensive care unit was at the discretion of the intensive care unit care team, but the institutional protocol is infusions of fentanyl or midazolam supplemented by propofol when necessary for patient comfort. This protocol was used for patients who did not receive dexmedetomidine and those who required intubation and sedation for >24 hours. We initiated the dexmedetomidine infusion at the rate of 0.24 to 0.60 g/kg per hour to minimize the potential for bradycardia or hypotension that might be associated with loading doses or higher infusion rates. Previous studies have demonstrated that, even with loading doses and higher infusion rates, bradycardia and hypotension are not significant complications in this setting. …
Effect of Changing Dietary Energy and Environmental Temperature on Feed Consumption of Large Broad Breasted White Turkey Hens

Abstract Five experiments were conducted to determine how quickly turkey hens in egg production adjusted their feed consumption when confronted with abrupt changes in environmental temperature and dietary energy. It was found that it was necessary to acclimatize the hens to the environmental chambers for seven days prior to beginning the treatments. After acclimatization, 1 to 8 days were necessary to completely adjust feed consumption in the 4.5° C. chamber and 8 to 14 days in the 35° C. chamber. There was no significant difference in feed consumption due to the change in dietary energy level when the hens were acclimatized prior to treatment.
Spatial and Temporal Patterns of Aspergillus flavus Strain Composition and Propagule Density in Yuma County, Arizona, Soils

Aspergillus flavus isolates from Arizona can be divided into S and L strains on the basis of sclerotial morphology. These genetically distinct strains differ in aflatoxin production. To help understand factors influencing the aflatoxin producing potential of A. flavus communities, spatial and temporal patterns of strain incidence were compared with patterns of A. flavus propagule density in Yuma County soils. Strain S isolates were found in all sampled fields, but the percentage of strain S isolates ranged from 4 to 93%. A nested analysis of variance was used to determine the spatial scale at which most variability in strain composition and propagule density occurred. For both variables, the largest component of variance occurred among fields within areas at a spatial scale of 1 to 5 km. There was also spatial structure (12 to 21% of the variance) at the subregional level (> 20 km) in strain composition, but not in propagule density. Temporal patterns for both variables were similar. The sampling periods with the highest incidence of strain S isolates, August 1994 (60%) and July 1995 (62%), occurred during cotton boll formation. The regional average for A. flavus propagule density was near 1000 propagules/g in the summer, but less than 100 propagules/g in the spring. The results suggest that insights into factors influencing the toxigenicity and propagule density of A. flavus communities might be achieved most readily by contrasting fields in close spatial proximity.
On the symbol error probability of maximum-selection diversity reception schemes over a Rayleigh fading channel

The symbol error probability of two selection schemes, namely, maximum signal-to-noise ratio (M gamma ) selection and maximum output (MO) selection, for M-ary multidiversity reception over a Rayleigh fading channel are discussed. The symbol error probability of the MO scheme is lower than that of the M gamma scheme. The more diversity receptions that are used, the larger is the difference. A simple expression of crossover average signal-to-noise ratio (per bit) is presented as a guideline for increasing the number of diversity receptions. >
OBSERVATIONS ON THE PHAGOCYTOSIS OF THE PNEUMOCOCCUS BY HUMAN WHOLE BLOOD : II. THE NEUTRALIZATION OF THE ANTI-PHAGOCYTIC ACTION OF THE SPECIFIC SOLUBLE SUBSTANCE BY ANTISERUM.

1. In vitro phagocytic experiments with human blood, antipneumococcus serum, pneumococcus specific soluble substance, and living virulent pneumococci show that there is a definite phagocytic inhibition zone when strong antiserum is used. 2. If the antiserum is further diluted, there is a zone where phagocytosis is effective. If the serum is diluted still more, phagocytosis gradually falls off, as the very dilute antiserum fails to neutralize the specific carbohydrate, which has a specific antiphagocytic action. 3. The inhibition zone is apparently caused by the specific precipitate (formed by the antiserum and the specific carbohydrate) interfering, perhaps mechanically, with the ingestion of the pneumococci by the leucocytes. 4. The inhibition zone is better marked with Type III than with Type I pneumococcus. 5. As the concentration of antiserum in the zone of effective phagocytosis in vitro does not correspond with the concentration of antiserum generally used in vivo in the serum therapy of pneumonia, this question is discussed.
Automatic Design of Practical Fixtures

Fixtures are tools used to hold parts in specific positions and orientations so that certain manufacturing steps can be carried out within required accuracies. Despite the importance of fixtures in the production of expensive devices at Sandia National Laboratories, there is little in-house expertise in mathematical design issues associated with fixtures. As a result, fixtures typically do not work as intended when they are first manufactured. Thus, an inefficient and expensive trial-and-error approach must be utilized. This design methodology adversely impacts important mission duties of Sandia National Laboratories, such as the production of neutron generators. The work performed under the support of this LDRD project took steps toward providing mechanical designers with software tools based on rigorous analytical techniques for dealing with fixture stability and tolerance stack-up.
An evolutionary computing approach to probabilistic reasoning on bayesian networks

Bayesian belief networks can be used to represent and to reason about complex systems with uncertain or incomplete information. Bayesian networks are graphs capable of encoding and quantifying probabilistic dependence and conditional independence among variables. Diagnostic reasoning, also referred to as abductive inference, determining the most probable explanation (MPE), or finding the maximum a posteriori instantiation (MAP), involves determining the global most probable system description given the values of any subset of variables. In some cases abductive inference can be performed with exact algorithms using distributed network computations, but the problem is NP-hard, and complexity increases significantly with the presence of undirected cycles, the number of discrete states per variable, and the number of variables in the network. This paper describes an approximate method composed of a graph-based evolutionary algorithm that uses nonbinary alphabets, graphs instead of strings, and graph operators to perform abductive inference on multiply connected networks for which systematic search methods are not feasible. The motivation, basis, and adequacy of the method are discussed, and experimental results are presented.
Bioprosthetic heart valve leaflet deformation monitored by double pulse stereo photogrammetry

Clinical application of bioprosthetic heart valves has been severely limited by the lack of valve durability. Among other contributing factors, one of the most evident is the stress and strain distribution in the leaflets. The focus of this paper is on the development of a new imaging technique to monitor the surface deformation of the leaflet under physiological conditions. The 3-D deformations of leaflet surfaces corresponding to the different phases of one cardiac cycle are reconstructed.