cssi/SciSciGPT-SciSciNet huggingface dataset:
Accuracy of Death Certificates for Coding Coronary Heart Disease as the Cause of Death

Background: Death certificates are widely used in epidemiologic and clinical investigations and for national statistics. Objective: To examine the accuracy of death certificates for coding coronary...
A multiparameter radar case study of the microphysical and kinematic evolution of a lightning producing storm

We examine the co-evolving microphysical, kinematic, and electrical characteristics of a multi-cell thunderstorm observed on 21 May 1993 along the Front Range of Colorado using data collected with the 11 cm, multiparameter, CSU-CHILL Doppler radar. The measured polarimetric variables provide information on the size, shape, orientation, and thermodynamic phase of hydrometeors. Recent modeling and observational advances in weather radar polarimetry now permit the inference of bulk-hydrometeor types and mixing ratios, and the measurement of precipitation rate in mixed-phase (i.e., hail and rain) environments. We have employed these and other radar techniques, such as dual-Doppler analyses, to investigate the correlation between the convective life cycle of a multi-cell storm and the evolution of lightning type and flash rate.
OPTIMAL INVESTMENT STRATEGIES FOR CONTROLLING DRAWDOWNS

We analyze the optimal risky investment policy for an investor who, at each point in time, wants to lose no more than a fixed percentage of the maximum value his wealth has achieved up to that time. In particular, if Mt is the maximum level of wealth W attained on or before time t, then the constraint imposed on his portfolio choice is that WtαMt, where α is an exogenous number betweenα O and 1. We show that, for constant relative risk aversion utility functions, the optimal policy involves an investment in risky assets at time t in proportion to the “surplus”Wt - αMt. the optimal policy may appear similar to the constant-proportion portfolio insurance policy analyzed in Black and Perold (1987) and Grossman and Vila (1989). However, in those papers, the investor keeps his wealth above a nonstochastic floor F instead of a stochastic floor αMt. the stochastic character of the floor studied here has interesting effects on the investment policy in states of nature when wealth is at an all-time high; i.e., when Wt =Mt. It can be shown that at Wt=Mt, αMt is expected to grow at a faster rate than Wt, and therefore the investment in the risky asset can be expected to fall. We also show that the investment in the risky asset can be expected to rise when Wt is close to αMt. We conjecture that in an equilibrium model the stochastic character of the floor creates “resistance” levels as the market approaches an all-time high (because of the reluctance of investors to take more risk when Wt=Mt).
Does restoration of antegrade flow in the infarct-related coronary artery days to weeks after myocardial infarction improve long-term survival?

Background Previous studies have shown that survival after myocardial infarction is influenced by the presence or absence of antegrade flow in the infarct-related artery: patients with antegrade flow have a good prognosis, whereas those whose infarct-related artery is occluded are less likely to survive. Because revascularization– via bypass grafting or angioplasty–is an effective means of reestablishing flow in the infarct-related artery, this study was done to assess the influence of revascularization in the days to weeks after infarction on long-term mortality in survivors of infarction who have an occluded infarct-related artery. Methods Over a 13-year period, 200 subjects (137 men, 63 women, aged 25 to 76 years) with their first infarction, no or minimal antegrade perfusion of the infarct-related coronary artery, and no disease of other arteries were followed for 42 ± 30 months. Of these, 148 (group I) were treated medically, whereas 52 (group II) had bypass grafting (n = 20) or angioplasty (n = 32) of the infarct-related artery. Results The groups were similar in age, sex, infarct-related artery, and left ventricular ejection fraction. Of the 148 group I subjects, 24 (16%) had cardiac-related mortality. In contrast, only one (2%) of the 52 group II subjects died of cardiac causes (P= 0.008). This difference was especially marked in patients with disease of the left anterior descending or left circumflex coronary arteries. Conclusions Thus, in survivors of myocardial infarction with limited or no antegrade flow in the infarct-related artery, mechanical restoration of antegrade perfusion may improve survival.
Chemisorption-induced changes of the surface dielectric function for W(110)

The change in reflectance due to adsorption of ${\mathrm{H}}_{2}$, ${\mathrm{O}}_{2}$, and CO on W(110) was measured for photon energies in the range 0.5 to 6.0 eV. The changes in dielectric function and joint density of states were obtained and analyzed in terms of vertical transitions in the projected band structure of the W(110) surface Brillouin zone. A new surface resonance is found above the Fermi level.
Method for evaluating optical characteristics of endoscopes for recording fluorescence-related cardiac electrical activity

Nondestructive methods were used to evaluate marketed fiber-optic endoscopes (intended for simple viewing) for fluorescence recording. Our application is for optical recording from the heart. For one angioscope, we measured a focal length of 0.33 mm, a field of view of 45°, an aperture of 0.26 mm, and an efficiency of 43%. We calculated that the angioscope would give a signal-to-noise ratio of 1.0 for a cardiac action potential, if its field of view were divided into a nine-pixel array (for safe continuous illumination). Our methods are useful in designing and evaluating fluorescence fiber-optic systems with superior signal quality and spatial resolution.
In Search of the Medulloblast: Neural Stem Cells and Embryonal Brain Tumors

Medulloblastomas have a cellular and molecular phenotype similar in many ways to that of neural stem cells. Indeed, it has long been believed that a medulloblastoma can arise from transformed neural stem cells. Recent analyses of murine transgenic lines has confirmed that cells of the external germinal layer (EGL) can be transformed into a medulloblastoma, generally in association with activation of the Hedgehog signaling pathway. Stem or progenitor cell populations outside the EGL, however, are also likely the cells of origin for a subset of medulloblastomas. Many nonnodular tumors, for example, express markers suggesting that they derive from the ventricular zone germinal layer and show evidence of Wnt pathway activation. Understanding the role of developmental signaling pathways, such as Hedgehog and Wnt, in the initiation and growth of embryonal brain tumors may lead to novel therapies for these highly malignant lesions. In addition, because such pathways are required in neural stem cells, their blockade may prove particularly effective in ablating the stem-like cells within medulloblastomas that are critical for tumor propagation. In support of this concept, inhibition of a third pathway important in stem cells, Notch, seems to deplete the stem-like tumor fraction and block formation of xenografts.
Image processing in digital radiography

Image processing is a critical part of obtaining high-quality digital radiographs. Fortunately, the user of these systems does not need to understand image processing in detail, because the manufacturers provide good starting values. Because radiologists may have different preferences in image appearance, it is helpful to know that many aspects of image appearance can be changed by image processing, and a new preferred setting can be loaded into the computer and saved so that it can become the new standard processing method. Image processing allows one to change the overall optical density of an image and to change its contrast. Spatial frequency processing allows an image to be sharpened, improving its appearance. It also allows noise to be blurred so that it is less visible. Care is necessary to avoid the introduction of artifacts or the hiding of mediastinal tubes.
Accumulation of neutral mutations in growing cell colonies with competition.

Abstract Neutral mutations play an important role in many biological processes including cancer initiation and progression, the generation of drug resistance in bacterial and viral diseases as well as cancers, and the development of organs in multicellular organisms. In this paper we study how neutral mutants are accumulated in nonlinearly growing colonies of cells subject to growth constraints such as crowding or lack of resources. We investigate different types of growth control which range from “division-controlled” to “death-controlled” growth (and various mixtures of both). In division-controlled growth, the burden of handling overcrowding lies with the process of cell-divisions, the divisions slow down as the carrying capacity is approached. In death-controlled growth, it is death rate that increases to slow down expansion. We show that division-controlled growth minimizes the number of accumulated mutations, and death-controlled growth corresponds to the maximum number of mutants. We check that these results hold in both deterministic and stochastic settings. We further develop a general (deterministic) theory of neutral mutations and achieve an analytical understanding of the mutant accumulation in colonies of a given size in the absence of back-mutations. The long-term dynamics of mutants in the presence of back-mutations is also addressed. In particular, with equal forward- and back-mutation rates, if division-controlled and a death-controlled types are competing for space and nutrients, cells obeying division-controlled growth will dominate the population.
Metabolic dynamics in skeletal muscle during acute reduction in blood flow and oxygen supply to mitochondria: in-silico studies using a multi-scale, top-down integrated model.

Control mechanisms of cellular metabolism and energetics in skeletal muscle that may become evident in response to physiological stresses such as reduction in blood flow and oxygen supply to mitochondria can be quantitatively understood using a multi-scale computational model. The analysis of dynamic responses from such a model can provide insights into mechanisms of metabolic regulation that may not be evident from experimental studies. For the purpose, a physiologically-based, multi-scale computational model of skeletal muscle cellular metabolism and energetics was developed to describe dynamic responses of key chemical species and reaction fluxes to muscle ischemia. The model, which incorporates key transport and metabolic processes and subcellular compartmentalization, is based on dynamic mass balances of 30 chemical species in both capillary blood and tissue cells (cytosol and mitochondria) domains. The reaction fluxes in cytosol and mitochondria are expressed in terms of a general phenomenological Michaelis-Menten equation involving the compartmentalized energy controller ratios ATP/ADP and NADH/NAD+. The unknown transport and reaction parameters in the model are estimated simultaneously by minimizing the differences between available in vivo experimental data on muscle ischemia and corresponding model outputs in coupled with the resting linear flux balance constraints using a robust, nonlinear, constrained-based, reduced gradient optimization algorithm. With the optimal parameter values, the model is able to simulate dynamic responses to reduced blood flow and oxygen supply to mitochondria associated with muscle ischemia of several key metabolite concentrations and metabolic fluxes in the subcellular cytosolic and mitochondrial compartments, some that can be measured and others that can not be measured with the current experimental techniques. The model can be applied to test complex hypotheses involving dynamic regulation of cellular metabolism and energetics in skeletal muscle during physiological stresses such as ischemia, hypoxia, and exercise.
Coronal Scale-Height Enhancement by Magnetohydrodynamic Waves

We discuss the possibility that the transmission of Alfven waves from the photosphere into coronal loops can increase the density scale height in these loops. The mechanism involved is the ponderomotive force of transmitted waves, which opposes the force of gravity. We propose that this effect may account for cool coronal loops observed by the Solar and Heliospheric Observatory(SOHO). We also suggest that it may be an explanation of the emission measure enhancement found at the top of coronal X-ray loops observed by Yohkoh. Subject headings: MHD — waves — gravitation — Sun: corona — Sun: magnetic fields Observations in the O v l629 line emission performed with the Coronal Diagnostic Spectrometer (CDS) on the Solar and Heliospheric Observatory(SOHO) show the existence of long, cool loops (viz., with temperature »240,000 K and height »50,000 km), at coronal altitudes significantly exceeding their density scale height and persisting over times much longer than the free-fall time. The present paper deals with a possible pro- cess that may lead to the appearance of such loops. A simple way of accounting for the lack of balance between the gravitational force and the thermal pressure in steady state is to postulate the presence of downflows, which in turn would require a constant resupply of plasma at coronal heights. The resupply could be the result of coronal condensations (Foukal 1978), but the occurrence of such condensations is uncertain. Force balance in the coronal loop can also be affected by the presence of magnetohydrodynamic (MHD) waves. Such an effect of electromagnetic waves has been the object of nu- merous investigations in the past, in contexts ranging from acceleration and confinement of laboratory plasmas (Motz & Watson 1967), magnetic field generation (Mora & Pellat 1979), low-frequency stability (Yasaka & Itatani 1984), to the solar wind (e.g., Hollweg 1973) and interstellar gasdynamics (McKee & Zweibel 1995), among others. In solar physics, sound wave pressure has been invoked in the context of planar models of the solar atmosphere (viz., McWhirter, Thoneman, & Wilson 1975; more recently, Woods, Holzer, & MacGregor 1990 and references therein). Such effects have also been con- sidered in the context of dynamic loop structures, in which torsional wave packets were assumed to move material along a loop axis (e.g., Shibata & Uchida 1986). Magnetohydrodynamic waves in coronal loops can be either excited in situ (e.g., by reconnection processes in the corona) or transmitted from the photosphere. Since the Alfven velocity cA in the corona is much larger than the photospheric Alfven velocity cAph, magnetohydrodynamic waves excited in the pho- tosphere tend to reflect in the transition region; significant en- ergy transmission occurs only at resonant frequencies at which standing waves are excited in the coronal portion of the loop (Hollweg 1984). If the loop magnetic field is uniform, this occurs for Alfven waves with parallel wavenumberk 5 res
Jake Sport Education a Step further: Add fitness

Abstract Combining two popular curriculums—sport education and fitness education—allows physical educators to use the best of both in their teaching.
The relationship between frequency selectivity and overshoot.

Under some conditions, threshold for a brief tone is higher at the onset of a broadband masker than it is if it is delayed from the onset of the masker. Evidence suggests that this “overshoot” is related to active processing in the auditory system. The present experiments examined this question, by measuring frequency selectivity under the same conditions in which overshoot was measured. The first experiment demonstrated that the growth of masking with masker level was approximately linear for a 1-kHz signal with or without a precursor (which was identical to the masker), and a 4-kHz signal with a precursor. For the 4-kHz signal with no precursor, an elevation in signal-to-masker ratio was seen at mid masker levels, relative to the other conditions. Frequency selectivity was then measured for a fixed-level signal, with and without a precursor. Relative frequency selectivity was highest for the 4-kHz signal with no precursor, lower for the 1-kHz signal with no precursor, and lowest for the 1- or 4-kHz signal with a precursor. The overshoot results and the frequency selectivity results would be consistent with stronger active processing at 4 kHz than at 1 kHz, and a decrease in active processing following a broadband noise precursor.
Replacement of polydentate ligands in Mn(II) complexes by ammonia

Abstract The synthesis and characterization of complexes of manganese (II) bromide with ethylenediamine, diethylenetriamine and triethylenetetramine are described. It is shown that, under appropriate conditions, these complexes are converted to hexamminemanganese (II) bromide by treatment with liquid ammonia.
Photoinduced spin waves in Fe/AlGaAs (001) heterostructure

Photoinduced spin waves are investigated for Fe films on AlGaAs (001) using the time resolved magneto-optical Kerr effect. We observe first and second order standing spin waves as well as uniform magnetization precession. The anisotropy fields and exchange stiffness constant are obtained from the field and azimuthal dependence of the spin wave frequencies using the Landau-Lifshitz-Gilbert equation. A comparison with spin wave resonance measurements reveals a more pronounced interface effect on the low order standing spin waves in thin films. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Indication for initiation of mechanical circulatory support impacts survival of infants with shunted single-ventricle circulation supported with extracorporeal membrane oxygenation

Objectives The use of extracorporeal membrane oxygenation to support patients with shunted single-ventricle physiology has been controversial. Variable survivals are reported in a number of small case series. We sought to evaluate outcomes and identify predictors of survival for patients with shunted single-ventricle physiology who require extracorporeal membrane oxygenation support. Methods We retrospectively reviewed the medical records of all patients aged less than 1 year with shunted single-ventricle physiology who were supported with extracorporeal membrane oxygenation at Children's Hospital Boston between 1996 and 2005. Survivors and nonsurvivors were compared with respect to demographics, diagnosis, operative variables, indication for extracorporeal membrane oxygenation, and extracorporeal membrane oxygenation variables. Results Forty-four infants with shunted single-ventricle physiology were supported with extracorporeal membrane oxygenation. Diagnoses included hypoplastic left heart syndrome (24), other single-ventricle lesions (12), and pulmonary atresia/intact ventricular septum or a variant (8). Overall survival to discharge was 48%. Indication for extracorporeal membrane oxygenation was the strongest predictor of survival to discharge, with 81% of patients cannulated for hypoxemia but only 29% of those cannulated for hypotension surviving to discharge. Specifically, patients cannulated for shunt obstruction had the highest survival (83%). Conclusions Overall survival to discharge for patients with shunted single-ventricle physiology is similar to survival reported in the Extracorporeal Life Support Organization registry for all infants supported with cardiac extracorporeal membrane oxygenation. Thus, shunted single-ventricle physiology should not be considered a contraindication to extracorporeal membrane oxygenation. Patients cannulated for hypoxemia, particularly shunt thrombosis, had markedly improved survival compared with those supported primarily for hypotension/cardiovascular collapse. Survival did not differ depending on anatomic diagnosis.
Polydimethylsiloxane- (PDMS-) Grafted Fluorocopolymers by a “Grafting through” Strategy Based on Atom Transfer Radical (Co)polymerization

Three types of PDMS-grafted fluorocopolymers with various branching features were synthesized based on atom transfer radical polymerization (ATRP) techniques via a “grafting through” approach using...
Preservation versus motorized recreation: Institutions, history, and public lands management

Abstract The management of the public lands in the United States has been shaped by the long-running conflict between environmental and utilitarian values. Recently, changing social expectations have increased demand for motorized recreational use and access. Critics contend such use of the public lands is a threat to their ecological health. Yet even as motorized use draws increased scrutiny and challenge, some commentators conclude that the battle is already over—and recreational users have won. This article focuses attention on the U.S. Forest Service and National Park Service and contends they are predisposed as institutions to favor demands for motorized recreational use and access. It concludes that what is needed is an explanation that seeks to place motorized recreational use in a historical and institutional context that offers a more complete understanding of why such users might be winning the battle.
Alpha radioactivity of unknown origin and the discovery of a new pleochroic halo

Abstract Several pleochroic halos of anomalous radii have been found. In general it is not possible to relate these halos to the uranium or thorium decay series alpha emitters. The discovery of a new halo (type G) corroborates previous evidence of presently unknown alpha radioactivity in crustal rocks.
Association of Kidney Function and Metabolic Risk Factors With Density of Glomeruli on Renal Biopsy Samples From Living Donors

OBJECTIVE To test the hypothesis that kidney function and metabolic risk factors are associated with glomerular density on renal biopsy samples from healthy adults. PATIENTS AND METHODS This study compared glomerular density with predonation kidney function, blood pressure, and metabolic risk factors in living kidney donors at Mayo Clinic in Rochester, MN, from May 10, 1999, to February 4, 2009. During implantation of the kidney allograft, an 18-gauge core needle biopsy sample of the renal cortex was obtained, sectioned, and examined by pathologists. Glomerular density was determined by the number of glomeruli (normal and sclerotic) divided by area of cortex. RESULTS The study sample of 1046 kidney donors had a mean of 21 glomeruli (0.8 sclerotic glomeruli) and a glomerular density of 2.3 glomeruli per square millimeter. In a subset of 54 donors, glomerular density inversely correlated with the mean glomerular area (r s =−0.28). Independent predictors of decreased glomerular density were older age, increased glomerular filtration rate, family history of end-stage renal disease, increased serum uric acid, and increased body mass index. Increased urine albumin excretion, hypertension, decreased high-density lipoprotein cholesterol, and metabolic syndrome were also associated with decreased glomerular density after age-sex adjustment. These associations were not explained by the presence of glomerulosclerosis, tubular atrophy, interstitial fibrosis, or arteriosclerosis on the renal biopsy sample. In older donors, decreased glomerular density was attenuated by an increased prevalence of glomerulosclerosis and tubular atrophy. CONCLUSION Decreased glomerular density is associated with many different kidney function and metabolic risk factors among relatively healthy adults and may represent an early state of increased risk of parenchymal injury.
Apical blebs on sperm storage tubule epithelial cell microvilli: Their release and interaction with resident sperm in the turkey hen oviduct

Located at the anterior end of the turkey hen's vagina are numerous discrete tubular invaginations of the surface epithelium, collectively referred to as the sperm storage tubules (SSTs). After mating or artificial insemination, sperm ascend the vagina, enter the SSTs, and over the ensuing days and weeks, gradually exit the SSTs and are transported to the anterior end of the oviduct to fertilize a daily succession of ova. Little is known regarding the cellular and molecular mechanisms responsible for sperm subsistence in the lumen of the SST. In this study, the origin of microvillus blebs (MvBs) on the apical tips of SST epithelial cells was examined, and their possible role in sperm survival was discussed. Regardless, if sperm are present or not, transmission electron microscopy revealed two types of microvilli differentiated by the presence or absence of pleomorphic unilaminar MvBs localized to their apical tips. Although some MvBs appeared to be discharging their contents into the SST lumen, others appeared to have pinched off the microvillus stem. When SSTs contained clusters of densely packed sperm, the sperm heads of those sperm adjacent to the SST epithelial cell surface were surrounded by the microvilli. Associated with the plasmalemma of sperm throughout the SST lumina were membrane fragments and small vesicles (30-130 nm in diameter), some of which appeared to have fused with sperm. It is concluded that the MvBs are a form of shedding vesicle released from the SST epithelial cell microvilli by apocrine secretion. On the basis of observations described herein and those of other authors, it is suggested that the MvBs contribute to sustained sperm storage in the SSTs by (1) supplying metabolic substrates used by resident sperm, (2) serving as fusogenic vehicles providing exogenous macromolecules that reversibly suppress sperm functions associated with fertilization (decapacitation?) and stabilize the sperm plasmalemma, and (3) acting as transport vesicles actively transporting fluid from the SST epithelial cells to the SST lumen.
Suppression of parathyroid hormone secretion by aluminum

The effect of aluminum on parathyroid hormone secretion was examined using collagenase-dispersed bovine parathyroid cells. An increase in the medium aluminum concentration over the range of 0.5 to 2.0 mM, in low calcium medium, progressively inhibited the secretion of radioimmuno-assayable hormone. At 2.0 mM aluminum hormone secretion was inhibited by 68% while high medium calcium, without aluminum, maximally inhibited parathyroid hormone secretion only 39%. Individually, 2.0 mM aluminum or 2.0 mM calcium inhibited isoproterenol-stimulated hormone secretion by 43%. Either metal suppressed basal and isoproterenol-stimulated cyclic AMP levels of the parathyroid cells. That the inhibitory effect of aluminum on parathyroid hormone secretion was not due to an irreversible toxic effect was demonstrated by a restoration of normal secretion when cells were returned to 0.5 mM calcium medium without aluminum. The incorporation of [3H]leucine into total cell protein, parathyroid secretory protein, proparathyroid hormone, or parathyroid hormone was not affected by aluminum. The secretion of radiolabeled protein was, however, inhibited by aluminum. These results suggest that aluminum does not affect protein biosynthesis of the parathyroid cell or the conversion of proparathyroid hormone to parathyroid hormone. Aluminum appears to directly affect the secretion of protein from dispersed parathyroid cells.
A molecule's right to choose: how diabetogenic class II MHC products bind peptides.

The distinction between peptides that bind to class II MHC products under laboratory conditions and those that do so physiologically is important for the prediction of antigens recognized by autoreactive T cells. In this issue of the JCI, Suri et al., using antigen-presenting cells, compared the peptides that bound to human HLA-DQ8 and those that bound to mouse I-Ag7, both class II MHC products that predispose their carriers to type 1 diabetes. The rules of engagement for the peptide ligands of the DQ8 and I-Ag7 molecules involve similarities in their anchor residues, which mediate stable interaction with class II MHC products. The peptides identified derive from overlapping sets of self proteins.
Body Mass Index Determines Evoked Growth Hormone (GH) Responsiveness in Normal Healthy Male Subjects: Diagnostic Caveat for Adult GH Deficiency

GH secretion is decreased in obese subjects, whereas age-adjusted IGF-I concentrations are normal. This study was undertaken to rigorously delineate the extent of obesity [elevated body mass index (BMI)] associated with decreased somatotrope secretory function resulting in apparent adult GH deficiency. The peak GH response evoked by combined arginine (0.5 g/kg infused iv over 30 min) and GHRH (1 μg/kg iv bolus) was measured in 59 healthy male subjects with BMIs ranging from normal to obese. BMI correlated with the peak evoked GH response (Pearson r = −0.59; P < 0.01), and the percentage of subjects exhibiting an abnormal evoked GH response, i.e. less than 9 ng/ml, increased from 5% for those with a BMI less than 25 (normal), to 13% for those with a BMI of 25–26.9 (mildly overweight), to 33% for those with a BMI of 27–29.9 (moderately overweight), and to 64% for those with a BMI of 30 or more (obese). BMI is a major determinant of evoked adult GH response to provocative testing. The diagnosis of adult GH d...
The Exception Who Proves the Rules: Ananse the Akan Trickster

Recent studies of the Trickster in world folklore1 have indicated his role as threat to the rules of societal and cosmic order. He is a paradoxical figure whose antics mock the seriousness of rules, the sacrality of beliefs, and the establishment of rituals. He is a vagabond, an intruder to proper society, an unpredictable liar who throws doubt on the concept of truth itself. As a folklore figure he is both human and divine, a person and an animal, creative and destructive, a success and failure. His tales are sometimes myths, sometimes legends, sometimes connected with ritual, sometimes not. They can be entertainment, education, a form of humorous rebellion. They can evaluate, explain, and reflect upon realities, thereby making those realities clearer and more profound to the people who tell and hear the tales. By breaking the patterns of a culture the Trickster helps define those patterns. By acting irresponsibly he helps define responsibility. He threatens, yet he teaches, too. He throws doubt on realities but helps concentrate attention on realities. He crosses supposedly unbreakable boundaries between culture and nature, life and death, and thereby draws attention to those boundaries. Societies "not only tolerate" Trickster tales, but "create and re-create"2 them because they serve the vital purpose of questioning and affirming, casting doubt and building faith upon the most important societal concepts. It is my purpose in this paper to examine the Trickster tales of the Twi-speaking peoples of West Africa, the Ashanti and other Akan. My interest is not in the stories as folklore, the relationships of their motifs to world folklore;3 rather, my aim is to discover the meanings of the Akan Trickster tales to the Akan. I wish to see them in their cultural context. I know that one can find similar episodes of similar Tricksters in the other areas of the world. Elsewhere the
Noisy Lagrangian Tracers for Filtering Random Rotating Compressible Flows

The recovery of a random turbulent velocity field using Lagrangian tracers that move with the fluid flow is a practically important problem. This paper studies the filtering skill of $$L$$ -noisy Lagrangian tracers in recovering random rotating compressible flows that are a linear combination of random incompressible geostrophically balanced (GB) flow and random rotating compressible gravity waves. The idealized random fields are defined through forced damped random amplitudes of Fourier eigenmodes of the rotating shallow-water equations with the rotation rate measured by the Rossby number $$\varepsilon $$ . In many realistic geophysical flows, there is fast rotation so $$\varepsilon $$ satisfies $$\varepsilon \ll 1$$ and the random rotating shallow-water equations become a slow–fast system where often the primary practical objective is the recovery of the GB component from the Lagrangian tracer observations. Unfortunately, the $$L$$ -noisy Lagrangian tracer observations are highly nonlinear and mix the slow GB modes and the fast gravity modes. Despite this inherent nonlinearity, it is shown here that there are closed analytical formulas for the optimal filter for recovering these random rotating compressible flows for any $$\varepsilon $$ involving Ricatti equations with random coefficients. The performance of the optimal filter is compared and contrasted through mathematical theorems and concise numerical experiments with the performance of the optimal filter for the incompressible GB random flow with $$L$$ -noisy Lagrangian tracers involving only the GB part of the flow. In addition, a sub-optimal filter is defined for recovering the GB flow alone through observing the $$L$$ -noisy random compressible Lagrangian trajectories, so the effect of the gravity wave dynamics is unresolved but effects the tracer observations. Rigorous theorems proved below through suitable stochastic fast-wave averaging techniques and explicit formulas rigorously demonstrate that all these filters have comparable skill in recovering the slow GB flow in the limit $$\varepsilon \rightarrow 0$$ for any bounded time interval. Concise numerical experiments confirm the mathematical theory and elucidate various new features of filter performance as the Rossby number $$\varepsilon $$ , the number of tracers $$L$$ and the tracer noise variance change.
Semiconductor alloys for monolithic integration with Si microelectronics

Abstract We introduce a novel class of semiconductors which is optically active and solves the problems with lattice-constant mismatches and polarity mismatches that are normally an issue in heteroepitaxial growth of III–V alloys on silicon substrates. Using ab initio total energy calculations and quasi-particle GW calculations we examine physical properties of various configurations of these novel materials and identify a particular suitable configuration. This configuration is lattice-constant matched to Si and has a direct band gap very close to the operating wavelength of optical fibers. Therefore, this novel class could lead to monolithic integration of optical materials and Si circuits.
Nutritional vitamin D use in chronic kidney disease: a survey of pediatric nephrologists

Background Vitamin D deficiency may contribute to risk of cardiovascular disease, diabetes, and infections, in addition to known effects on mineral metabolism. Controversy remains regarding the use of nutritional vitamin D supplementation in chronic kidney disease (CKD), and the supplementation practices of pediatric nephrologists are unknown.
In situ assays demonstrate that interferon-gamma suppresses infection-stimulated hepatic fibrin deposition by promoting fibrinolysis.

Summary. Background: Inflammatory cytokines potently impact hemostatic pathways during infection, but the tissue-specific regulation of coagulation and fibrinolysis complicates studies of the underlying mechanisms. Methods and Results: Here, we describe assays that quantitatively measuring prothrombinase (PTase), protein C-ase (PCase) and plasminogen activator (PA) activities in situ, thereby facilitating studies of tissue-specific hemostasis. Using these assays, we investigate the mechanisms regulating hepatic fibrin deposition during murine toxoplasmosis and the means by which interferon-gamma (IFN-γ) suppresses infection-stimulated fibrin deposition. We demonstrate that Toxoplasma infection upregulates hepatic PTase, PCase, and PA activity. Wild type and gene-targeted IFN-γ-deficient mice exhibit similar levels of infection-stimulated PTase activity. By contrast, IFN-γ-deficiency is associated with increased PCase activity and reduced PA activity during infection. Parallel analyses of hepatic gene expression reveal that IFN-γ-deficiency is associated with increased expression of thrombomodulin (TM), a key component of the PCase, increased expression of thrombin-activatable fibrinolysis inhibitor (TAFI), a PC substrate, and reduced expression of urokinase PA (u-PA). Conclusions: These findings suggest that IFN-γ suppresses infection-stimulated hepatic fibrin deposition by suppressing TM-mediated activation of TAFI, thereby destabilizing fibrin deposits, and concomitantly increasing hepatic u-PA activity, thereby promoting fibrinolysis. We anticipate that further application of these in situ assays will improve our understanding of tissue-specific hemostasis, its regulation by cytokines, and its dysregulation during coagulopathy.
Azetidine based transition state analogue inhibitors of N-ribosyl hydrolases and phosphorylases.

N-Ribosyl phosphorylases and hydrolases catalyze nucleophilic displacement reactions by migration of the cationic ribooxacarbenium carbon from the fixed purine to phosphate and water nucleophiles, respectively. As the lysis reaction progresses along the reaction coordinate, the distance between the purine and carbocation increases and the distance between carbocation and nucleophile decreases. Immucillin-H and DADMe-immucillin-H have been shown previously to be potent inhibitors of purine nucleoside phosphorylases and lie more toward the reactant and products side of this reaction coordinate, respectively. Both these enzyme inhibitors, which are currently in human clinical trials for different indications, are chiral and expensive to manufacture. We now report the synthesis of azetidine analogues of the DADMe-immucillins, which, despite their lack of stereochemical complexity, remain potent inhibitors (equilibrium dissociation constants as low as 229 pM) of purine nucleoside phosphorylase (PNP), methylthi...
Responsiveness to the Negative Affect System as a Function of Emotion Perception Relations Between Affect and Sociability in Three Daily Diary Studies

Perceiving emotions clearly and accurately is an important component of emotional intelligence (EI). This skill is thought to predict emotional and social outcomes, but evidence for this point appears somewhat underwhelming in cross-sectional designs. The present work adopted a more contextual approach to understanding the correlates of emotion perception. Because emotion perception involves awareness of affect as it occurs, people higher in this skill might reasonably be expected to be more attuned to variations in their affective states and be responsive to them for this reason. This novel hypothesis was pursued in three daily diary studies (total N = 247), which found systematic evidence for the idea that higher levels of daily negative affect predicted lesser sociability particularly, and somewhat exclusively, among people whose emotion perception skills were high rather than low. The results support a contextual understanding of individual differences in emotion perception and how they operate.
Tunable Regulation of the Serca/Phospholamban Complex by Single-Stranded DNA Sequences

Heart disease is a leading cause of death in the Western world.1 Failing hearts have been shown to exhibit abnormal calcium cycling within cardiomyocytes.2-5 While there are several proteins that are involved with the calcium pathway in cardiomyocytes, the sarcoplasmic reticulum Ca2+ -ATPase (SERCA) and phospholamban (PLN) function in the important role of calcium reuptake into the SR for storage. SERCA is inhibited by PLN, a 52 amino acid, single-pass membrane protein. Upon PLN phosphorylation at Ser16, this inhibition is relieved and SERCA's calcium affinity is restored to normal levels. It has been proposed that by reversing PLN's inhibition on SERCA in patients with heart failure proper Ca2+ homeostasis and muscle contractility may be restored.6 Using biophysical, biochemical, and analytical techniques including; enzyme coupled activity assays, solid and solution state nuclear magnetic resonance (NMR), fluorescence polarization, and affinity capillary electrophoresis we show that single stranded DNA sequences (ssDNA) target the SERCA/PLN complex and fully restore the ATPase function. Inportantly, ssDNA sequences bind PLN at a nanomolar level of affinity. The restoration of SERCA activity by ssDNA is elicited in a length-dependent manner. Studying the unique interactions between the PLN and ssDNA will give us insight into this chemical and molecular mechanism that allows for restoration of SERCA activity and will aid in the development of small molecules able to interfere with the SERCA/PLN complex for possible therapeutic interventions.
Conditional equilibrium and the equivalence of microcanonical and grandcanonical ensembles in the thermodynamic limit

Equivalence (allowing for convex combinations) of microcanonical, canonical and grandcanonical ensembles for states of classical systems is established under very mild assumptions on the limiting state. We introduce the notion of conditional equilibrium (C.E.), a property of states of infinite systems which characterizes convex combinations of limits of microcanonical ensembles. It is shown that C.E. states are, under quite general conditions, mixtures of Gibbs states.
Connectivity of identified central synapses in the cricket is normal following regeneration and blockade of presynaptic activity

Cercal sensory neurons in the cricket innervate interneurons in the central nervous system (CNS) and provide a model system for studying the formation of central synapses. When axons of the sensory neurons were transected during larval development, the cell bodies and the soma-bearing portion of axons, which are located within the cercus, survived but lost their excitability for 9-10 days. During this period, the sensory neurons grew new axons and reinnervated the terminal abdominal ganglion. Physiological recordings showed that sensory neurons of known identity reestablished monosynaptic contacts with their normal postsynaptic interneuron. Moreover, each synapse exhibited a characteristic strength indistinguishable from the intact synapse in an unoperated cricket. Since this selective connectivity was apparent immediately after the excitability of the axotomized sensory neurons was restored, action potentials in the sensory neurons appear to be unnecessary for normal synaptic regeneration to occur. Consistent with this, the reinnervation process was unaffected even when action potentials in the sensory neurons were blocked by tetrodotoxin (TTX) immediately following axotomy until just before testing. During the normal course of development, the characteristic strength of individual synapses changes systematically, resulting in the developmental rearrangement of these synapses (Chiba et al., 1988). This synaptic rearrangement was also unaffected when action potentials in the sensory neurons were blocked by TTX for the last 30% of larval development. Therefore, in the cricket cercal sensory system, both regeneration of the central synapses following axotomy of the presynaptic sensory neurons and the normal rearrangement of connectivity during larval development appear not to require axonal action potentials.
Western blot screening for monoclonal antibodies against human separase

Separase is a cysteine protease that participates in separation of sister chromatids during mitosis. Human separase is a 230-kDa enzyme that is inhibited by binding to its protein inhibitor securin, specific phosphorylation, and subcellular localization. To further characterize human separase, we raised monoclonal antibodies specific against a C-terminal fragment of the protein. A critical step in monoclonal antibody production procedure is the primary screening of hybridoma supernatants. Here we report primary screening protocol utilizing Western blot analysis. The described screening protocol is carried out using fusion of a human separase fragment with two different purification tags, maltose-binding protein (MBP) and glutathione S-transferase (GST). Immunization by MBP-fusion was followed by primary screening with both MBP- and GST-separase fusions combined in the same preparation separated in SDS-PAGE. This highly sensitive screening approach reduced the number of positive signals by eliminating antibodies specific for the purification tag used in the immunization procedure. The described separase-specific antibodies were suitable for detection of endogenous separase in crude extracts, immunoprecipitation, and immunofluorescent cell staining experiments. The presented procedure is fast, reproducible and could be adopted as a primary screening scheme for a variety of protein antigens.
Modified luneberg lens for defocused source

A spherical Luneberg lens has the property of focusing the rays from a point source on the surface of the lens into a collimated beam on the diametrically opposite side of the lens. In microwave applications a point source on the surface of the lens is usually not obtained. Curves are given for the required index of refraction for a modified Luneberg lens which possesses the same collimating property for a point source located at a small distance outside of the lens.
Immunization with immune complex alters the repertoire of antigen-reactive B cells in the germinal centers.

The differentiation of memory B cells in germinal centers (GC) is selectively enhanced upon administration of antigen-antibody complexes. To characterize the repertoire of this response, we examined the rearranged immunoglobulin heavy chain variable (V(H)) genes from mouse splenic GC after a single immunization with either antigen, nitrophenyl (NP) hapten coupled to keyhole limpet hemocyanin, or with a preformed complex of antigen with a monoclonal anti-NP antibody of gamma1 isotype. Among antigen-immunized mice, NP-reactive GC B cell populations in the antigen-induced GC consisted mostly of cells expressing the canonical V186.2 gene which contained, on average, 0.8 point mutations/V(H) gene by day 8 after immunization. These results are indicative of the beginning of somatic hypermutation and consistent with previously published analyses of NP antigen-driven GC. In contrast, the NP-specific B cells in GC that were elicited by administration of immune complex represented a heterogeneous cell population expressing nine different germ-line segments of the V186.2/V3 (J558) gene family, i.e. V23, V24.8, C1H4, V3, CH10, V165.1, V102, V671.5 and V186.2. Moreover, the average frequency of mutations in these genes was 1.7, reaching up to 4 mutations/V(H) in some GC. Administration of the antigen NP in complex with specific antibody apparently alters the process of interclonal competition in the GC and results in loss of dominance by V186.2+ cells and nearly stochastic representation of diverse clonotypes. These results suggest an important feedback regulation of the B cell repertoire by antibody and indicate a role for immune complexes in the activation of somatic hypermutation.