cssi/SciSciGPT-SciSciNet huggingface dataset:
Evolutionary paths under catastrophes

We introduce a model to study the impact of catastrophes on evolutionary paths. If we do not allow catastrophes the number of changes in the maximum fitness of a population grows logarithmically with respect to time. Allowing catastrophes (no matter how rare) yields a drastically different behavior. When catastrophes are possible the number of changes in the maximum fitness of the population grows linearly with time. Moreover, the evolutionary paths are a lot less predictable when catastrophes are possible. Our results can be seen as supporting the hypothesis that catastrophes speed up evolution by disrupting dominant species and creating space for new species to emerge and evolve.
The Spirit the Triumph

crutches artificial arms have you seen that? how they pick their cups up and use razors? amazing! and the wives shine it for them at night they're sleeping the wives take it out of the room and polish it with its own special rag it's late they hold it against their bellies the leather laces dangle into their laps the mechanisms slip noiselessly lowering the hook softly onto their breasts we men! aren't we something? I mean we are worth thinking about aren't we? we are the end we are the living end
High-fiber diet in HIV-positive men is associated with lower risk of developing fat deposition

Background: Lipodystrophy has been described with increasing frequency in patients infected with HIV. This study focused on the identification of dietary components that may predispose HIV-positive patients to the development of fat deposition. Objective: We evaluated differences in past dietary intake between men with HIV who developed fat deposition and those who did not. Design: This nested case-control study consisted of 47 cases and 47 controls from the Nutrition for Healthy Living cohort. Food records from 6 to 24 mo before development of fat deposition in cases were analyzed and compared with food records from controls by using t tests for normally distributed nutrients and Wilcoxon rank-sum tests for nutrients with skewed distributions. Results: HIV-positive patients without fat deposition had greater overall energy intakes (kcal/kg; P = 0.03) and greater intakes of total protein (P = 0.01), total dietary fiber (P = 0.01), soluble dietary fiber (P = 0.01), insoluble dietary fiber (P = 0.03), and pectin (P = 0.02) than did HIV-positive patients with fat deposition. Those without fat deposition also tended to currently perform more resistance training (P = 0.05) and to not be current smokers (P = 0.05). Conclusion: Our results indicate that an overall high-quality diet, rich in fiber and adequate in energy and protein, may be beneficial in preventing the development of fat deposition in persons infected with HIV. The results of this study further emphasize that a healthy lifestyle, including exercise and avoidance of unhealthy behaviors such as smoking, may also be similarly beneficial.
Continuity and Discontinuity of Collaboration Behaviour since 1800 — from a Bibliometric Point of View

Abstract Time-series of collaboration trends indicated through co-authorships are examined from 1800 to presence in mathematics, logic, and physics. In physics, the share of co-authored papers expands in the second half of the19th century, in mathematics in the first decades of the 20th century, in logic in the second half of the 20th century. Subdisciplines of mathematics, of physics, and areas of logic show large differences in their respective propensities to collaborate. None of the existing explanatory approaches meets this heterogeneity; the most salient feature is a propensitiy to collaborate in fields where theoretical and applied research is combined.
Diagnosing dementia in the oldest-old

The "oldest-old" comprise the fastest growing segment of the population in much of the world. Rates of dementia are extremely high in this age group and will present a major public health burden as the numbers of these individuals quadruple by the middle of the century. Studies in this age group are rare and frequently have small numbers of participants. In research studies and the clinic, the diagnosis of dementia and determination of the etiology of the disorder are challenging. In this review, we include some of our experiences in a population-based longitudinal investigation, The 90+ Study. Oldest-old individuals are more likely to suffer from medical comorbidities and have high rates of sensory loss, psychoactive medication usage, frailty and fatigue. Moreover, social and cultural expectations affect the reporting and interpretation of behavioral changes. These and other factors make it difficult to determine the relative contributions of cognitive losses and non-cognitive losses in the development of functional disability. Contributing further to the complexities of diagnosis, current research suggests that dementia in the oldest-old, compared to younger people, is more likely to be related to mixed disease pathologies. Frequent cerebral neuropathologies include Alzheimer's disease neurodegeneration, small and large vessel vascular disease, and hippocampal sclerosis. More research is necessary in the oldest-old to better understand the etiologies of dementia in this age group, and factors that may affect the expression of disease as we age.
Critical Exponent Inequalities and the Continuity of the Inverse Range of Correlation

The inverse range of correlation for nearest-neighbor, ferromagnetic, Ising models is shown to vanish continuously as the temperature approaches the critical temperature. An example is also given where this property fails. The critical index obeys $\ensuremath{\nu}g~\frac{2}{(d+1)}$. Attention is drawn to the relevance of continuity to mass renormalizability in Euclidean boson quantum field theory.
An assessment of structure and causation of IS usage

Factors contributing to information system (IS) usage are of interest to both academicians and practitioners alike. Previous research has shown that perceived usefulness and perceived ease of use are two dominant factors affecting an individual's intention to use a system. Different models of the causal relationships between perceived usefulness, perceived ease of use, and system usage have been investigated in the literature (Adams, Nelson, and Todd, 1992). Contributing to this body of knowledge, this paper reports on the analysis of three competing models of Davis's constructs: perceived ease of use, perceived usefulness, and intention to use. The results indicate Davis is correct in proposing that the indirect relationship between perceived ease of use and intention to use, mediated by perceived usefulness, is an important one. In addition, the direct relationship between perceived ease of use and intention to use, is also significant. The study's findings indicate the full Davis model with all causal paths is superior to alternative nested models tested.
Analysis of striking distances of lightning strokes to vertical towers

The two criteria (E- and V-criterion) concept is proposed for estimating the striking distance of a stepped leader to a vertical tower. The tower was modelled as a stack of ring charges by charge simulation method. It was found that the radial striking distance to a vertical tower varied with the lateral distance of the descending stepped-leader tip from the struck object. The lateral striking distance is defined as the farthest lateral distance of the stepped-leader tip from the vertical tower that produces a strike. The stepped-leader parameters, such as the height, charge distribution and polarity, affect the striking distance to the tower. Because of the stochastic nature of these parameters, the statistical variations of these parameters must be known. The tower height and radius also affect the striking distance to the tower.
The Crystal Structure of Yeast Thiamin Pyrophosphokinase

Abstract Background: Thiamin pyrophosphokinase (TPK) catalyzes the transfer of a pyrophosphate group from ATP to vitamin B 1 (thiamin) to form the coenzyme thiamin pyrophosphate (TPP). Thus, TPK is important for the formation of a coenzyme required for central metabolic functions. TPK has no sequence homologs in the PDB and functions by an unknown mechanism. The TPK structure has been determined as a significant step toward elucidating its catalytic action. Results: The crystal structure of Saccharomyces cerevisiae TPK complexed with thiamin has been determined at 1.8 A resolution. TPK is a homodimer, and each subunit consists of two domains. One domain resembles a Rossman fold with four α helices on each side of a 6 strand parallel β sheet. The other domain has one 4 strand and one 6 strand antiparallel β sheet, which form a flattened sandwich structure containing a jelly-roll topology. The active site is located in a cleft at the dimer interface and is formed from residues from domains of both subunits. The TPK dimer contains two compound active sites at the subunit interface. Conclusions: The structure of TPK with one substrate bound identifies the location of the thiamin binding site and probable catalytic residues. The structure also suggests a likely binding site for ATP. These findings are further supported by TPK sequence homologies. Although possessing no significant sequence homology with other pyrophospokinases, thiamin pyrophosphokinase may operate by a mechanism of pyrophosphoryl transfer similar to those described for pyrophosphokinases functioning in nucleotide biosynthesis.
The Life and Science of Alfred H. Woodcock

The stock market crash of 1929 plunged the United States into the greatest crisis since the Civil War, and by the spring of 1931 the country had entered the long dark night of an economic depression. But in the small seaside town of Daytona, Florida, Mrs. Woodcock didn’t have time to worry about the state of the country. She had something else to worry about. Her youngest son, Alfred, had just quit his job on a farm in Massachusetts. Leaving one job for something better is perhaps an admirable thing to do, but this was his 25th job since dropping out of high school about 10 years before. And what was his 26th job to be? A sailor! Woodcock decided that he wanted to go to sea. His mother, of course, had no way of knowing this was to be his last job, one that would lead him into science. To her it was just the latest in a long line of jobs that seemed to go on and on and on. She was really worried.
Double beta-disintegration

From the Fermi theory of $\ensuremath{\beta}$-disintegration the probability of simultaneous emission of two electrons (and two neutrinos) has been calculated. The result is that this process occurs sufficiently rarely to allow a half-life of over ${10}^{17}$ years for a nucleus, even if its isobar of atomic number different by 2 were more stable by 20 times the electron mass.
The effect of processing conditions on the compressive and shear strength of 2-D carbon-carbon laminates

Abstract An experimental study was performed to determine the effect of processing conditions on the failure mechanisms and strength of 2-D carbon-carbon laminates under uniaxial compression and shear loading. Specifically, the mechanical properties are related to the size and density of material discontinuities which, in turn, depend upon the numbers of matrix impregnation and carbonization cycles, and subsequent heat treatments. Five samples with different numbers of carbonization and heat-treatment cycles were considered; all had the same 8 harness-fiber-weave architecture and 0 ° 0 ° layup. Compressive strengths ranging from 130 to 270 MPa were obtained. All samples failed through the formation of a diagonal shear fault across the laminate which, on the local scale, consisted of bundle kinks (at crimps) interspersed with interply delaminations. Failure mechanisms under both interlaminar and in-plane shear loading were also determined for all the samples by using a direct shear setup. Interlaminar shear strengths (ILSS) ranged from 5 to 8 MPa, and in-plane shear strengths were in the range of 15 to 28 MPa. The failure under ILSS loading was through the formation of a planar shear fault following the crimp boundaries, whereas under in-plane shear, the failure was through interply delaminations on sample faces normal to the plies.
On the production of displaced atoms by thermal neutrons

Abstract The production of displaced atoms by processes resulting from thermal neutron capture are discussed. The results of an approximate calculation are presented which indicate that, in a number of elements, the number of displaced atoms produced by the recoil following capture γ-ray emission may form an appreciable fraction of the total number of displaced atoms produced in a reactor experiment. The unique features of the radiation damage produced by thermal neutrons are noted, and some considerations attendant upon isolating and using such reactions in damage experiments are discussed.
The dynamics of support: The winners–losers gap in attitudes toward EU membership in post-communist countries

We examine the question of whether economic winners were more likely to support European Union (EU) membership than economic losers in post-communist countries. We include in our analysis every cross-national survey of post-communist countries with both a measure of individual attitudes toward EU membership as well as an appropriate measure of individual self-assessment of economic progress. The resultant data set contains data from 67 different surveys over a 12-year period (1991–2003) in all 10 post-communist countries that have joined the EU to date. Using a variety of analytical techniques, ranging from simple cross-tables and multivariate analysis of the individual surveys to multilevel models of a fully pooled data set, we show that the pattern of economic winners being more likely to support EU membership for their country is remarkably consistent across both time and space. At the same time, the dynamic component of the analysis allows us to show that the size of this gap varies over time, with winners being even more likely to support EU membership than losers when EU membership is a more realistic possibility.
Changes in unit responses to tones after food reinforcement in the auditory pathway of the rat: intertrial arousal.

Abstract Experiments were carried out to determine the effects of short-term changes in behavioral arousal on the responsiveness to auditory stimuli of medial geniculate and inferior colliculus neurons in the rat. The independent variable was the time of presentation of the signals after a food pellet, the assumption being that the animal's state of arousal might vary after a consummatory act, and that this fact in turn might modify unit activity. Eight different periods were tested in a random order of presentation, the periods varying between 20 and 180 s from the time of presentation of a food reward. The findings indicate increased responsiveness after long intervals, as measured in peak response firing rate, together with decreased spontaneous rate in a 200-ms period before the auditory signals (background rate). The results demonstrate that variations in arousal during the short periods between food rewards in the paradigm tested influence both the spontaneous rate of discharge and the responsiveness of auditory neurons to sensory input, but that the pattern of changes is different in the medial geniculate and in the inferior colliculus. These variations are of a short-term nature compared with the long-term variations that have come to be expected with changes in the motivational or sleep-wake state of the animal. Recognition of this type of modulating influence is of great importance to neurophysiological studies of learning, in view of the fact that associative neural changes have to be extracted from the nonassociative changes that occur simultaneously.
Latitude: How American Astronomers Solved the Mystery of Variation

First longitude, now latitude. From Latitude's title we cannot help thinking of Dava Sobel's recent bestseller, Longitude. I suppose it's unlikely to be such a moneymaker, but this delightful new book by Bill and Merri Sue Carter, a father and daughter team, is similar to Sobel's book. Both are physically small, with short chapters, which makes for a quick read. And both have a clear hero: John Harrison and his chronometers for longitude; and Seth Carlo Chandler Jr. and his almucantar for latitude. Both books eschew academic-style footnoting, although Latitude does list a few useful sources for each chapter and provides a comprehensive list of Chandler's astronomical publications. Chandler's name is known to most AGU members for its association with the 14-month wobble of the Earth's pole. He also discovered the slightly smaller annual wobble, and an argument can be made that he was the principal discoverer of polar motion, or latitude variation, in general.
“I have a Preschool Buddy” Exploring the Role of High School Students in Facilitating the Pre-academic Skills and Social Development of Preschool Children

The purpose of this research is to explore the role of a director of a preschool program who mentors and trains high school students to teach and work directly with preschool children in the context of individual lessons, small group activities, and large group instruction. This participant-observer research study also examines how the director assesses the high school students’ ability to work effectively with the preschoolers they are assigned to teach and addresses the pre-academic and social learner outcomes for these children in this unique preschool program. Parent feedback pertaining to preschool learning outcomes is also examined.
Effects of paclitaxel on cytokine synthesis by unprimed human monocytes, T lymphocytes, and breast cancer cells

Paclitaxel or Taxol has attracted a great deal of attention in recent years because of its immense success as a chemotherapeutic agent for numerous types of cancer. It is known that paclitaxel stabilizes microtubules, and this characteristic is the presumed primary mechanism for its antitumor activity. Recently, however, paclitaxel’s ability to regulate gene expression, particularly in the murine system, has been reported by several groups. Here, we present research examining paclitaxel’s ability to alter expression of the interleukin-1β (IL-1β) and IL-8 cytokines in primary human monocytes, T lymphocytes, and four human breast cancer cell lines: MCF-7, ZR-75-1, MDA-MB-468, and MDA-MB-231. This report shows for the first time that treatment with 5–50 μM paclitaxel increases steady-state levels of IL-1β mRNA in unprimed human monocytes, MCF-7, and ZR-75-1 cells. Monocytes from eight donors in 16 experiments showed increased IL-1β secretion upon treatment; however, the increase in IL-1β production by monocytes was predicated on culturing in the absence of fetal bovine serum or in the presence of autologous human serum. In contrast to the IL-1β results, paclitaxel did not have significant effects on IL-8 expression by monocytes, T lymphocytes, or the breast cancer cells. These data show a specific effect of paclitaxel on cytokine synthesis by both immune cells and cancer cells.
Instabilities of dynamic thermocapillary liquid layers. I Convective instabilities

A steady shear flow is set up in a planar liquid layer bounded below by a rigid plate, and above by an interface with a passive gas, by imposing a temperature gradient along the layer and driving the motion by thermocapillarity. The thermal-convective instabilities to which this dynamic state is susceptible include stationary longitudinal rolls involving the classical Marangoni instability, and unsteady hydrothermal waves, whose new instability mechanism derives its energy from the horizontal temperature gradients. The thermal stability characteristics for liquid layers with and without return flow profiles are presently given as functions of the Prandtl number for the liquid and the Biot number for the interface, and comparisons are made with available experimental observations.
Self-assembly of ink molecules in dip-pen nanolithography: A diffusion model

The self-assembly of ink molecules deposited using dip-pen nanolithography (DPN) is modeled as a two-dimensional diffusion with a source (tip). A random walk simulation and simple analytic theory are used to study how the diffusion dynamics affects patterns generated in DPN. For a tip generating a constant flux of ink molecules, circles, lines, and letters are studied by varying the deposition rate of ink molecules and the tip scan speed. Even under the most favorable condition studied here, peripheries of patterns fluctuate from perfect circles or lines, due to the random, diffusional nature of self-assembly. The degree of fluctuation is quantified for circles and lines. Circles generated by fixing the tip position do not depend on the deposition rate if the same amount of ink is deposited. For a moving tip, patterns change drastically depending on tip speed and deposition rate. Overall, fast scan or slow deposition relative to the diffusion time scale makes lines narrower. When the tip deposits ink too ...
Ab initio study of Eu3+–L (L=H2O, H2S, NH2CH3, S(CH3)2, imidazole) complexes

Abstract The ground states and binding energies of Eu 3+ –L (L=H 2 O,H 2 S,NH 2 CH 3 ,S(CH 3 ) 2 , imidazole) complexes has been determined using ab initio techniques. The binding is mostly electrostatic as expected. The empty f orbital is different for the S compounds, being a π-like orbital, while for the O and N containing ligands it is a σ-like orbital. However, the range in the binding energies for the different f holes is small.
MOTION OF NORMAL REGIONS ALONG A SUPERCONDUCTING STRIP.

The local temperature and heat current density in a superconducting strip whose ends are maintained at constant temperature are calculated for the case of periodically repeating motion of magnetic-flux-containing normal regions along the strip. The effective transport entropy per unit length per flux quantum, associated with the motion, is calculated; reasonable agreement with experiment is found. The power dissipation arising from the presence of temperature gradients is found to be small by comparison with the electrical dissipation in pure, but not in impure, superconductors. The presence of local thermal gradients is estimated to have an important influence upon the thermogalvanomagnetic effects in superconductors.
Periodontal considerations in implant dentistry.

Abstract In spite of the tremendous progress that has been made and the information that has been accumulated, the oral implantologist operates with relatively meager knowledge. He works on an empirical platform, only because so little research has been done and so many questions are unanswered. It will probably be years before his science begins to catch up with his art. In the meantime, by borrowing from the wealth of knowledge in the field of periodontology and by applying it directly, he can operate with direction and confidence. The more the oral implantologist appreciates the similarity, almost the congruency, between the periodontal environment of the teeth and that surrounding an endosteal implant, the more frequently he will be able to achieve success in this demanding area. But to do this, he must at present work on an assumption. It is a most logical assumption. Time will give the final answer, but in the meantime, the occlusion must be designed to protect implants from occlusal trauma. Plaque retention must be avoided by (1) using open embrasures, (2) using supragingival margins wherever esthetics will allow them, (3) elimination of furcations, (4) meticulous removal of plaque by the patient, (5) placement of implant posts in attached gingiva rather than movable mucosa wherever feasible, and (6) avoiding muscle pull on the posts.
Role of thrombin in endothelial cell monolayer repair in vitro

Abstract Purpose: We examined the effect of thrombin on human iliac artery endothelial cell monolayer repair and proliferation after denuding vascular injury. Methods: Human iliac artery endothelial cell monolayer repair was determined by scrape wounding confluent monolayers and measuring the advancement of the cells into the wounded area for 3 days. Proliferation studies involved plating human iliac artery endothelial cells at one tenth confluence and counting the increase in cell number every 2 days for a 2-week period. Proliferation during monolayer repair was examined by determining bromodeoxyuridine uptake in cells located at the leading edge of a scrape-wounded monolayer. Results: Thrombin (1 to 8 U/ml) inhibited human iliac artery endothelial cell monolayer repair in a concentration-related, reversible manner. The effect was augmented by decreasing serum concentration and was independent of the presence of endothelial cell growth supplement. Inactivation of thrombin's proteolytic site with diisopropylfluorophosphate eliminated its effect on monolayer repair. Thrombin (0.5 to 8 U/ml) inhibited human iliac artery endothelial cell proliferation in a dose-related manner. This effect was augmented by decreasing serum concentration. Finally, thrombin (4 U/ml) inhibited the proliferative response of cells located at the leading edge of wounded monolayers compared with control groups. Conclusion: Thrombin inhibits human arterial endothelial cell monolayer repair and proliferation after denuding vascular injury. (J VASC SURG 1994;20:621-8.)
LIDAR monitoring of the environment

LIDAR has to be considered as a key-tool for environmental remote sensing. A LIDAR measurement, based on the laser induced spectroscopy of a remote target, give the possibility of an accurate and fast monitoring of wide areas with good spatial and temporal resolution. LIDAR applications range from atmosphere to earth-surface remote sensing, offering the possibility of measuring significant environmental parameters, such as the concentration of different pollutants and of biological pigments. LIDAR sensors have been successfully employed from different mobile platforms, including van, ship, helicopter and aeroplane.
Different mismatch repair deficiencies all have the same effects on somatic hypermutation: intact primary mechanism accompanied by secondary modifications.

Somatic hypermutation of Ig genes is probably dependent on transcription of the target gene via a mutator factor associated with the RNA polymerase (Storb, U., E.L. Klotz, J. Hackett, Jr., K. Kage, G. Bozek, and T.E. Martin. 1998. J. Exp. Med. 188:689–698). It is also probable that some form of DNA repair is involved in the mutation process. It was shown that the nucleotide excision repair proteins were not required, nor were mismatch repair (MMR) proteins. However, certain changes in mutation patterns and frequency of point mutations were observed in Msh2 (MutS homologue) and Pms2 (MutL homologue) MMR-deficient mice (for review see Kim, N., and U. Storb. 1998. J. Exp. Med. 187:1729–1733). These data were obtained from endogenous immunoglobulin (Ig) genes and were presumably influenced by selection of B cells whose Ig genes had undergone certain mutations. In this study, we have analyzed somatic hypermutation in two MutL types of MMR deficiencies, Pms2 and Mlh1. The mutation target was a nonselectable Ig-κ gene with an artificial insert in the V region. We found that both Pms2- and Mlh1-deficient mice can somatically hypermutate the Ig test gene at approximately twofold reduced frequencies. Furthermore, highly mutated sequences are almost absent. Together with the finding of genome instability in the germinal center B cells, these observations support the conclusion, previously reached for Msh2 mice, that MMR-deficient B cells undergoing somatic hypermutation have a short life span. Pms2- and Mlh1-deficient mice also resemble Msh2-deficient mice with respect to preferential targeting of G and C nucleotides. Thus, it appears that the different MMR proteins do not have unique functions with respect to somatic hypermutation. Several intrinsic characteristics of somatic hypermutation remain unaltered in the MMR-deficient mice: a preference for targeting A over T, a strand bias, mutational hot spots, and hypermutability of the artificial insert are all seen in the unselectable Ig gene. This implies that the MMR proteins are not required for and most likely are not involved in the primary step of introducing the mutations. Instead, they are recruited to repair certain somatic point mutations, presumably soon after these are created.
A study of the phosphorescent triplet state of cycloalkanones by pulse optically detected magnetic resonance

Abstract Previous studies of saturated cycloalkanones have characterized the phosphorescent triplet state as n,π*. To elucidate further the characteristics of the excited state of these compounds of photochemical importance, we report the dephasing studies on the spin coherence in the phosphorescent triplet state. For these molecules where the excitation is localized on the carbonyl moiety, spin relaxation is a direct function of the perturbing atoms in the vicinity of the chromophore.
Cascaded robust nonlinear position tracking control of an electrohydraulic actuator: Sliding mode and feed forward

An approach to position tracking control based on a cascade of a nonlinear force tracking controller derived from a near input-output linearization framework and a simple feedback plus feed forward position controller is presented. The method exploits the cascade structure to employ a sliding mode pressure force tracking controller as inner-loop and the position tracking controller as an outer-loop. Furthermore, it is highlighted that Lyapunov backstepping analysis can be used to drive performance bounds and reveal trade-offs between the size of uncertainty and measurement errors and the tracking accuracy. The performance of the proposed cascaded robust controller is demonstrated with experiments and simulations on a test system that doesn't necessarily satisfy all of the assumptions made for controller derivation. In particular, a typical comparison of the robust and nominal cascade controllers shows the robust version can recover the performance of the nominal near IO linearizing controller. In addition, model simulation results are included to show the performance of the controller in the presence of some combinations of perturbations or difficult to estimate parameters such as valve coefficient, supply pressure, piston friction, and inclusion of servovalve spool dynamics.© 2006 ASME
Nanoparticles: Designer labels for virus coats

Protein nanoparticles derived from viruses are commonly studied, but a new rod-shaped thermophilic virus isolated from acidic hot springs may yield another class of protein building blocks that are stable and can be selectively modified with diverse chemical groups.
Supraventricular tachycardia in a heart transplant recipient: What is the mechanism?

45-year-old woman was referred for evaluation of palpiations and supraventricular tachycardia. She had undergone n orthotopic heart transplant using a standard atrioatrial nastomosis 4 years earlier due to end-stage idiopathic diated cardiomyopathy. She had been experiencing several onths of intermittent palpitations associated with a regular achycardia of 150 bpm (Figure 1). Some episodes degenrated to atrial fibrillation prior to termination. Echocardigraphy showed normal left ventricular function. The most ecent right ventricular biopsy showed no evidence of graft ejection. At electrophysiologic study, the patient arrived in sinus hythm, with the same rate in both donor (transplant) and ecipient atria. A 20-pole catheter was looped in the right trium, with distal three bipoles in the donor coronary sinus. uadripolar catheters were placed in the His-bundle region nd right ventricular apex. Pacing in the donor right atrium howed 1:1 response in both donor and recipient atria to 260 s. Pacing in the recipient right atrium showed 1:1 response n the donor atria to 260 ms as well. Burst atrial pacing in he recipient right atrium induced the rhythm shown in igure 2. What is the mechanism of the tachycardia, and hat is the best approach to ablation?
Effect of Increasing Dietary Levels of Acetyl-Salicylic Acid on Performance and Cecal Microbial Counts of White Leghorn Pullets

Abstract INTRODUCTION AN earlier report from this station, Reid et al. (1964), showed that when 0.05% acetyl-salicylic acid (ASA) was fed White Leghorn pullets either alone or in combination with 27.5 mg. oxytetracycline per kg., a significant increase in egg production resulted. The improvement was independent of periods of high ambient temperature and thus the action of the drug was assumed to be exclusive of its antipyretic properties. Since both drugs allowed increased production, alone or in combination, a possible antimicrobial action for ASA could be inferred. Investigation of this point and the effect of possible toxic dietary levels in birds housed in range shelters or individual wire cages was the objective of these studies. EXPERIMENTAL PROCEDURE Two experiments were conducted using commercial strain Single Comb White Leghorn pullets. In the first study, two randomly selected pens (40 birds/pen) were fed each experimental diet while four replicate groups of 5 birds …
Vigilance in recovering cocaine-dependent and alcohol-dependent patients: A prospective study☆

Abstract Electroencephalographic activity and psychomotor performance were evaluated in 11 cocaine-dependent and 4 alcohol-dependent patients, after 1, 3, and 12 weeks of verified abstinence, and 15 non-drug-dependent age-matched controls, while they performed a 30-min signal-detection task. The task consisted of lower and higher pitched tones, 100 msec in duration, occuring in randomized order at a rate of 1 every 2 seconds. Subjects were asked to press a response key whenever they detected the less frequent (p = 0.3), higher pitched tone. Over the course of the 30 min task, subjects responded less frequently and more slowly to the higher pitched tone. Also, the amount of slow wave (i.e., alpha) activity in their EEGs increased. There were no differences among the groups with respect to the rate or magnitude of these time-related decrements in performance and electroencephalographic arousal. The only dependent variable which differentiated groups was reaction time, averaged across the duration of the task. Overall, the cocaine dependent group responded 80–100 msec slower than the other groups. In the context of other findings, this finding of increased reaction time among recovering cocaine dependent patients is interpreted as reflecting an effect of previous cocaine use on neural processes involved in the programming and/or execution of motor responses.
Methanol cracking of Ti-8Al-1Mo-1V

Abstract A comparison is made between methanol and salt-solution cracking of Ti-8Al-l Mo-1V. Cracking characteristics are similar in that the beta and martensite phases have higher resistance and in that cleavage in the alpha phase must occur near the basal plane in both environments. Although cracking occurs at a lower stress level in methanol, some step in the cleavage process is apparently slower than in salt solution.
Neocortical hyperexcitability in a human case of tuberous sclerosis complex and mice lacking neuronal expression of TSC1

Objective To identify brain regions, cell types, or both that generate abnormal electrical discharge in tuberous sclerosis complex (TSC). Here we examined excitatory and inhibitory synaptic currents in human tissue samples obtained from a TSC patient with no discernible cortical tubers and acute neocortical brain slices from a mouse featuring synapsin-driven conditional deletion of a TSC1 gene. These studies were designed to assess whether TSC gene inactivation alters excitability. Methods We used visualized patch-clamp (human and mouse) and extracellular field (mouse) recordings. Additional mice were processed for immunohistochemistry or Western blot analysis. Results Detailed anatomic studies in brain tissue sections from synapsin-TSC1 conditional knock-out mice failed to uncover gross anatomic defects, loss of lamination, or frank tuber formation. However, regions of abnormal and potentially activated neocortex were shown using antibodies to nonphosphorylated neurofilaments (SMI-311) and immediate early genes (c-Fos). Extracellular recordings from neocortical slices, examining synaptic activity in these regions, demonstrated clear differences in excitability between conditional knock-out and age-matched control mice. Whole-cell patch-clamp recordings demonstrated excitatory synaptic currents with strikingly long duration and epileptiform discharge patterns, similar to waveforms observed in our human tissue samples. These events were 1-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptor mediated and were most prominent in neocortex. Normal-appearing inhibitory postsynaptic currents (human) and intrinsic neuronal firing patterns (mouse) were also recorded. Interpretation This combination of human and mouse tissue studies suggests, for the first time, that synaptic excitation is altered in a direction that favors seizure generation in TSC brain tissue regardless of cortical tubers. Ann Neurol 2007
Superconformal supergravity and internal symmetry

Abstract The Weyl-like gauging of Wess-Zumino superconformal symmetry and of its internal symmetric generalizations SU(2,2|N) are treated. The prolification of gauge fields is much more modest than in super-Riemannian theories. Unlike supergravity, a field theory of this type is still a unified theory that provides its own sources.
Cytosar-U (ARA-C) induced changes in mouse jejunal crypt epithelial kinetics and radiosensitivity to gamma rays and fast neutrons☆

Abstract Pretreatment with the S phase specific cytotoxic agent Cytosine Arabinoside (Ara-C) protects the intestinal stem cells from gamma radiation injury by nearly tenfold. Studies were undertaken to test whether an altered cell age distribution could account for the reported duration and degree of Ara-C induced protection and to measure the degree of protection from the high energy neutrons of the Fermilab Cancer Treatment Facility. Twelve hours after treatmentwith Ara-C, B6CF 1 /ANL mice wereexposed to increasing single doses of either 137 Cs γ-rays or neutrons from the Fermilab accelerator, or a split dose of neutrons with intervals of 1, 2, and 3 hours. The number of regenerating microcolonies per jejunal circumference in Ara-C treated and irradiated animals was compared to irradiated controls. Another group of mice was given Ara-C but in the 12-hour interval between Ara-C and irradiation, colcemid was given every 3 hours to continuously block and kill cells in mitosis. The results suggest that Ara-C given 12 hours prior to neutron irradiation protects intestinal stem cells to nearly the same degree as it does from 137 Cs γ-ray damage. Furthermore, the control split-dose recovery ratio to neutron irradiation at 1, 2, or 3 hours was 1.8 and was unchanged 12 hours after Ara-C. Colcemid reduced the crypt cell population to less than half the normal 250 cells per crypt; however, the cell survival curve was unaltered from the survival curve 12 hours after Ara-C. These results suggest that Ara-C recruits intestinal clonogenic stem cells, but inhibits their normal passage through DNA synthesis. These cells, responsible for intestinal mucosal regeneration, appear to be held in a radioresistant portion of the cell cycle for a period of about 10–16 hours after Ara-C.
Use of alternative childhood immunization schedules in King County, Washington, USA

Abstract Objective To determine the percentage of parents in King County, Washington using an alternative childhood immunization schedule (ACIS) and the type of ACIS used. Patient and Methods We distributed self-administered surveys to parents at 5 practices regarding the immunization schedule they planned to use or were using. Parents who selected an ACIS were asked to describe its main characteristics and information source. Results We received 517 surveys and included 502 in analysis. The percentage of parents using an ACIS was 9.4% (95% CI: 7%, 12.2%). Only 6% described their ACIS as the Dr. Sears Schedule, although the book in which it is featured was the most frequently cited ACIS information source (29%). There was a significant association between ACIS use and non-Hispanic white parents and parents of children 12–23 months old. Conclusion(s) A minority of King County parents use an ACIS. The Dr. Sears Schedule does not predominate.
Pattern of lobate scarps on Mercury’s surface reproduced by a model of mantle convection

Numerical simulations suggest that lobate scarps on the surface of Mercury could have resulted from compressive stresses induced by convection within the planet’s mantle, in addition to those generated by global contraction. Mercury is the smallest and least tectonically active of the terrestrial planets1,2. Although Mercury’s ancient, cratered surface resembles the Moon, it has the largest ratio of metallic core to silicate mantle among the terrestrial planets3 as well as an internal magnetic field4. Images from the Mariner 10 spacecraft reveal lobate scarps, so called because of their curved or scalloped edges, which have been interpreted to be high-angle thrust faults5,6,7,8 resulting from a period of global contraction. A range of mechanisms has been invoked to explain the stresses leading to global contraction, including cooling and core formation5,9, tidal effects due to gravitational interactions with the Sun10, mantle convection11 and the impact that formed the Caloris basin12. Here I present numerical simulations of the three-dimensional nature of convection within Mercury’s silicate mantle. The model yields a regularly spaced pattern of convection, in which upwelling regions of the mantle assume linear, sheet-like shapes at low latitudes and a nearly hexagonal pattern near the poles. The distribution of resultant surface stresses is consistent with the observed pattern of lobate scarps, suggesting that the compressive features record an ancient pattern of mantle convection11, in addition to global contraction. The gravity and topographic data returned from the MESSENGER 11 mission13 will help test this hypothesis.
ON THE "RAWNESS" OF SUBSOILS.

1. Suboils of arid regions are certainly no less "raw" than those of semi-arid regions, and probably only slightly less so than those of humid regions. 2. If, as seems as yet unproved, inoculated legume seeds fail to develop on humid subsoil material, such failure can not justifiably be attributed as is done by Alway, McDole and Rost, to a lack of available phosphoric acid and potash. 3. A lack of available nitrogen probably is sufficient to account for rawness of subsoils. 4. The poor aeration of subsoils which indirectly results in their rawness, may be accounted for more simply than by Hilgard9s explanation of the washing down of fine particles into the subsoil, which prevents proper aeration.
Optimizing a cleaning process for multilayer dielectric (MLD) diffraction gratings

A critical component for the OMEGA EP short-pulse petawatt laser system is the grating compressor chamber (GCC). This large (12,375 ft 3 ) vacuum chamber contains critical optics where laser-pulse compression is performed at the output of the system on two 40-cm-sq-aperture, IR (1054-nm) laser beams. Critical to this compression, within the GCC, are four sets of tiled multilayer-dielectric- (MLD) diffraction gratings that provide the capability for producing 2.6-kJ output IR energy per beam at 10 ps. The primary requirements for these large-aperture (43-cm × 47-cm) gratings are diffraction efficiencies greater than 95%, peak-to-valley wavefront quality of less than λ/10 waves, and laser-induced-damage thresholds greater than 2.7 J/cm 2 at 10-ps measured beam normal. Degradation of the grating laser-damage threshold due to adsorption of contaminants from the manufacturing process must be prevented to maintain system performance. In this paper we discuss an optimized cleaning process to achieve the OMEGA EP requirements. The fabrication of MLD gratings involves processes that utilize a wide variety of both organic materials (photoresist processes) and inorganic materials (metals and metal oxides) that can affect the final cleaning process. A number of these materials have significant optical absorbance; therefore, incomplete cleaning of these residues may result in the MLD gratings experiencing laser damage.
Chiral symmetry breaking and meson-nucleon sigma commutators: A review

Chiral symmetries are discussed in considerable detail, and their importance and consequences for the study of elementary particle physics are reviewed. For the study of broken symmetries we concentrate mainly on meson-nucleon sigma terms, $\ensuremath{\pi}\ensuremath{\pi}$ scattering, and ${K}_{l3}$ decays. In addition to giving a critical and detailed review of most of the "experimental" estimates for pion-nucleon and kaon-nucleon sigma terms done so far, we also outline the most common chiral symmetry-breaking schemes at present, such as $(3,\overline{3})+(\overline{3},3)$, $(6,\overline{6})+(\overline{6},6)$, (8,8) and (1, 8) + (8, 1) representations of SU(3) \ifmmode\times\else\texttimes\fi{} SU(3) and possible mixtures of them, and discuss and compare their predictions with experiment. Nonlinear effective Lagrangians are briefly discussed, and the connection between broken scale invariance and chiral symmetry breaking is outlined, with emphasis on our present knowledge of meson-nucleon sigma terms.
Medical Registries: Continued Attempts for Robust Quality Data

Medical registries are useful to summarize retrospective or prospective data in a fashion that, on interpretation, could result in changes in the standard of care or highlight issues that must be further investigated in the management of certain diseases. Registries involve collection of data and registries are only as good as the fidelity of the data that are collected. There are a number of sources of error in registry formation. This brief review summarizes the errors that could influence the quality of the data in a registry and points out methods that could decrease those errors.
Horizons inside classical lumps.

We investigate the possibility of having horizons inside various classical field configurations. Using the implicit function theorem, we show that models satisfying a certian set of criteria allow for (at least) small horizons within extended matter fields. Gauge and global monopoles and Skyrmions satisfy these criteria. $Q$ balls and boson stars are examples which do not and can be shown not to allow for horizons. In examples that do allow for horizons, we show how standard "no hair" arguments are avoided.
ON THE NATURE OF INTRA- AND INTERSPECIFIC INCOMPATIBILITY IN ULMUS

Efforts to introduce Dutch Elm Disease resistance into the American elm (Ulmus americana L.) through breeding with Asian elms has been hampered by sexual incompatibility. Controlled pollinations of Ulmus americana and the Siberian elm (Ulmus pumila L.) were studied in detail to gain insight into the nature of this incompatibility. Microscopic observations revealed that germination and early pollen tube growth were inhibited on the stigmatic surface following both intra- and interspecific incompatible pollinations. Both qualitative and quantitative differences in pollen inhibition on the stigmatic surface indicated that the inhibition may involve the action of an inhibitory substance. Detailed observations on callose deposition indicated that this 3-I,3 glucose polymer may implement the inhibition.