cssi/SciSciGPT-SciSciNet huggingface dataset:
Overview of the programmer's apprentice

This note gives an overview of the Programmer's Apprentice system being developed at MIT. This system is conceived as being midway between an aid to improved programming methodology and an automatic programming system. A programmer and the apprentice work together throughout all phases of the development and maintenance of a program. The programmer does the difficult parts of design and implementation, while the apprentice acts as a Junior partner and critic, keeping track of details and assisting the programmer wherever possible. A key feature of the apprentice is its ability to understand the logical structure of a program so that It can interact with the programmer In e meaningful way.
Adiabatic inversion pulses for myocardial T1 mapping.

Purpose To evaluate the error in T1 estimates using inversion-recovery-based T1 mapping due to imperfect inversion and to perform a systematic study of adiabatic inversion pulse designs in order to maximize inversion efficiency for values of transverse relaxation (T2) in the myocardium subject to a peak power constraint. Methods The inversion factor for hyperbolic secant and tangent/hyperbolic tangent adiabatic full passage waveforms was calculated using Bloch equations. A brute-force search was conducted for design parameters: pulse duration, frequency range, shape parameters, and peak amplitude. A design was selected that maximized the inversion factor over a specified range of amplitude and off-resonance and validated using phantom measurements. Empirical correction for imperfect inversion was performed. Results The tangent/hyperbolic tangent adiabatic pulse was found to outperform hyperbolic secant designs and achieve an inversion factor of 0.96 within ±150 Hz over 25% amplitude range with 14.7 µT peak amplitude. T1 mapping errors of the selected design due to imperfect inversion was ∼4% and could be corrected to <1%. Conclusions Nonideal inversion leads to significant errors in inversion-recovery-based T1 mapping. The inversion efficiency of adiabatic pulses is sensitive to transverse relaxation. The tangent/hyperbolic tangent design achieved the best performance subject to the peak amplitude constraint. Magn Reson Med 71:1428–1434, 2014. © 2013 Wiley Periodicals, Inc.
The biosynthesis of folic acid. XI. Purification and properties of dihydroneopterin aldolase.

Abstract The enzyme that catalyzes the removal of a two-carbon compound from 2-amino-4-hydroxy-6-(d-erythro-1',2',3'-trihydroxypropyl)-7,8-dihydropteridine (known by the trivial name of dihydroneopterin) to yield 2-amino-4-hydroxy-6-hydroxymethyl-7,8-dihydropteridine, has been purified by approximately 1100-fold from extracts of Escherichia coli B. The two-carbon compound formed as a product has been identified as glycolaldehyde. Since the reaction is similar to those reactions catalyzed by aldolases, the enzyme has been named dihydroneopterin aldolase. The enzyme is relatively heat-stable in that it can withstand a temperature of 100° for 5 min with virtually no loss of activity. The enzyme functions optimally at pH 9.6. The addition of chelating agents such as EDTA markedly increases the activity of the enzyme. The Km for dihydroneopterin is approximately 9 µm. The enzyme cannot use the following compounds as substrates in place of dihydroneopterin: neopterin, tetrahydroneopterin, dihydroneopterin monophosphate, and dihydroneopterin triphosphate. The product of the reaction, 2-amino-4-hydroxy-6-hydroxymethyl-7,8-dihydropteridine, is a potent inhibitor of the reaction. Other dihydropteridines, including dihydropteroic acid and dihydrofolic acid, are less potent inhibitors. It was found that purified dihydroneopterin aldolase could use as substrate an epimer of dihydroneopterin, i.e. 2-amino-4-hydroxy-(6-l-threo-trihydroxypropyl)-7,8-dihydropteridine, but the corresponding d-threo and l-erythro compounds could not be utilized, although the l-erythro compound could be utilized for the synthesis of 2-amino-4-hydroxy-6-hydroxymethyl-7,8-dihydropteridine in the presence of purified dihydroneopterin aldolase and another enzyme fraction obtained from extracts of E. coli. This suggests that E. coli contains an enzyme that catalyzes the epimerization of the l-erythro compound to a compound that can be used directly as substrate by the purified aldolase (presumably the corresponding l-threo compound).
Thirty-day outcomes of cerebrospinal fluid shunt surgery: data from the National Surgical Quality Improvement Program-Pediatrics

Object Cerebrospinal fluid shunts are the mainstay of the treatment of hydrocephalus. In past studies, outcomes of shunt surgery have been analyzed based on follow-up of 1 year or longer. The goal of the current study is to characterize 30-day shunt outcomes, to identify clinical risk factors for shunt infection and failure, and to develop statistical models that might be used for risk stratification. Methods Data for 2012 were obtained from the National Surgical Quality Improvement Program-Pediatrics (NSQIP-P) of the American College of Surgeons. Files with index surgical procedures for insertion or revision of a CSF shunt composed the study set. Returns to the operating room within 30 days for shunt infection and for shunt failure without infection were the study end points. Associations with a large number of potential clinical risk factors were analyzed on a univariate basis. Logistic regression was used for multivariate analysis. Results There were 1790 index surgical procedures analyzed. The overall...
The Girl Next Door: A Comparative Approach to Prostitution Laws and Sex Trafficking Victim Identification Within the Prostitution Industry

V. Comparative Approach: Prostitute Unions, Self-Regulation and "Sex Trafficking" 533 A. Criminalized Jurisdiction: The United States 536 B. Legalized Jurisdiction: Victoria, Australia 538 C. Decriminalized Demand: The United Kingdom 543 D. Decriminalization: New Zealand 548
Socialization of teenage girls through teen-magazine fiction: The making of a new woman or an old lady?

A content analysis of the fiction in Seventeen and 'Teen revealed that few of the stories offered anything but traditional socialization messages for teenage girls. In more than half, the main character did not actively solve her own problems but depended on someone else to do it for her. Almost half of the conflicts were about relationships with boys. Excluding the 10 rated by coders as neutral, all but 2 of the 44 occupations mentioned in the stories were stereotypically portrayed.
Variation in working memory capacity and episodic recall: The contributions of strategic encoding and contextual retrieval

The present study examined the extent to which differences in strategic encoding and contextual retrieval account for the relation between individual differences in working memory capacity (WMC) and variation in episodic recall. Participants performed a continual distractor task under either incidental- or intentional-encoding conditions. High-WMC individuals outperformed low-WMC individuals across both encoding conditions and, notably, to a greater degree in the intentional-encoding condition. These results suggest that WMC differences in episodic recall are likely due to a combination of differences in both contextual-retrieval and strategic-encoding processes. These findings are consistent with prior work showing that high-WMC individuals are better at engaging in strategic-encoding processes during the presentation of items than are low-WMC individuals and are better at using contextual cues to focus the search on correct items during retrieval.
Characterization of DNA‐protein complexes induced in intact cells by the carcinogen chromate

Potassium chromate induced the formation of DNA-protein complexes in cultured Chinese hamster ovary cells. The DNA-protein complexes were isolated by ultracentrifugal sedimentation in the presence of 2% sodium dodecyl sulfate (SDS) and 5 M urea. Two-dimensional SDS-polyacrylamide gel electrophoresis analysis of the chromate-induced DNA-protein complexes revealed that two acidic proteins of 53 and 45 kDa and a basic protein of 54 kDa were selectively complexed to the DNA. Numerous other proteins also became associated with the DNA to a lesser degree as the chromate concentration was increased. Nuclease digestion was not a prerequisite for the resolution of the protein component of the DNA-protein complexes using two-dimensional gel electrophoresis. Ultracentrifugal analysis of the DNA-protein complexes in the presence of proteinase K, nucleases, or a chelating agent demonstrated that protein aggregation was not responsible for the increased protein recovery in chromate-treated samples and that the complexes were disrupted by EDTA. These data suggest that the selectively complexed proteins were associated with the DNA through strong interactions that may be mediated by the trivalent form of chromium.
Angiography in hydronephrosis.

Abstract In hydronephrosis, the angiogram enables assessment of the vascular architecture of the kidney, the amount of parenchyma present, or the possibility of a vascular cause for the obstruction. The loss or amputation of arcuate or interlobular arteries on the angiogram is an early sign of hydronephrotic atrophy. Pathophysiologically, these changes antedate the narrowing of the renal artery reported to be indicative of irreversible renal damage. The presence of normal peripheral renal vasculature is a favorable prognostic indicator for recovery of renal function following relief of hydronephrosis. The loss of arcuate and interlobular vessels on the angiogram of a hydronephrotic kidney, regardless of renal artery diameter, augurs poorly for functional improvement following corrective surgery.
Semiconductor surface diffusion: Effects of low-energy ion bombardment

We offer a revised mechanism to describe our previous measurements of surface diffusion under low-energy ion bombardment in the Ge/Si(111) system. We show that direct ion-induced motion of diffusing atoms (the effect commonly cited as important in ion beam assisted deposition) cannot account for these observations. Instead, we rationalize the results through processes in which ions create long-lived surface vacancies or spatially extended defects that heal continuously during bombardment. These ideas rationalize several important aspects of the experimental data that were previously unexplained, including the appearance of ion effects at very low ion fluxes, the simple Arrhenius behavior of the diffusivity, the rough magnitudes of the observed energy thresholds, and the ion-induced inhibition of diffusion at high temperatures.
On estimating an upper bound to MSE of position error in time-of-arrival position location systems

This paper defines a closed-form expression for an upper bound to MSE of position error in terms of statistics of an observable parameter: the residual. The upper bound estimation is verified through simulations including different geometries of receivers and different magnitudes of errors. The number of receivers needed to measure accuracy is discussed for the proposed bounds. Furthermore, this paper introduces a novel measure of accuracy of a positioning system using a single receiver, given the smallest number of receivers used to locate a transmitter.
Treatment of Primary Central Nervous System Lymphoma

Primary central nervous system lymphoma (PCNSL) is a rare form of extranodal non-Hodgkin’s lymphoma that is typically confined to brain, eyes, and cerebrospinal fluid without evidence of systemic spread. The prognosis of patients with PCNSL has improved during the past decade with the introduction of high-dose methotrexate with or without whole brain radiotherapy. However, despite recent progress, results following treatment are durable in few patients, and therapy can be associated with late neurotoxicity. PCNSL is an uncommon tumor, and no phase III trial has been completed so far, leaving many questions about its optimum first-line and salvage treatments unanswered. This review summarizes the literature regarding the treatment of PCNSL in immuno-competent patients.
Polymer donor–polymer acceptor (all-polymer) solar cells

Organic photovoltaic (OPV) cells represent an exciting class of renewable energy technology; they are lightweight and flexible, and have a low production cost. Over the last two decades, the efficiency of these devices has improved significantly, in particular through the development of solution-processed bulk heterojunction (BHJ) OPV cells. While fullerenes have been the most intensively studied acceptor materials in BHJ OPVs, research is currently underway in several groups investigating non-fullerene molecular acceptors. In this review, initial breakthroughs and recent progress in the development of polymer donor-polymer acceptor (all-polymer) BHJ OPVs are highlighted.
La retórica de la peste: imaginería apocalíptica en los tratados de peste del Renacimiento peninsular

This article examines the spectacular representation of plague in three Renaissance medical treatises written in vernacular Spanish: Hexameron theologal sobre el regimiento medicinal contra la pestilencia (1519) by Pedro Ciruelo, Discurso breve sobre la cura y preservacion de la pestilencia (1556) by Andres Laguna, and Remedios preservativos y curativos para en tiempo de peste (1597) by Miguel Martinez de Leyva. Heavily tinged with catastrophic nuances, these treatises include hyperbolic prologues where the authors engage in a discussion about which of the four apocalyptic foes is the worst, concluding that plague is the most fearful one, as it not only leads men to death, but it also provokes the dissolution of social structures. Understanding these texts as spaces of negotiation where both anxieties over illness and a rationalizing intention converge, this study explores their organizing rhetoric and, more concretely, the symbolic value of rhetoric, which emerges here as weapon and antidote against the ...
The Medical Wilderness Adventure Race (MedWAR): a 2-year perspective on a unique learning experience.

Effective medical education requires a combination of didactic instruction and practical experience. Although most medicine can be taught in a clinic or hospital where patients are readily available, the challenge of providing a good, practical wilderness medicine experience is that both students and teachers must leave this traditional setting. Students must be provided with an opportunity to practice medicine. In many medical fields, instructors are able to perform their clinical duties while they are teaching. This model is more difficult to implement when teaching wilderness medicine. Didactic instruction may take place in the lecture hall, and even hands-on workshops can be given in the classroom, but the true practice of wilderness medicine does not happen until the classroom is hours away. To remove the students and instructors from the classroom, we created an event called the Medical Wilderness Adventure Race (MedWAR). This event provided a way for medical providers to test their judgment when cold, tired, wet, and hungry. The MedWAR requires competitors to appropriately manage a number of medical scenarios placed throughout an adventure race. The events have included hiking, canoeing, a ropes portion, and orienteering. Events have lasted anywhere between 4 and 12 hours. The mission statement of MedWAR includes the phrase ‘‘To develop bonds of collegiality between participants from different schools, hospitals, professions, areas, and backgrounds.’’ This event has indeed managed to attract participants from all levels of training and disciplines. The majority of participants have been medical students and residents, though other groups have been represented and competitive. Paramedics, college students, nurses, physician assistants, and army medical corps personnel have all raced. In the upcoming event this summer, a team of Eagle Scouts is planning to race.
Failure to detect superoxide in human neutrophils stimulated with latex particles.

Summary: Human neutrophils stimulated with either latex particles or opsonized zymosan exhibited equivalent rates of net oxygen consumption as well as hydrogen peroxide release. The quantity of superoxide (O2-) detected in latex-stimulated neutrophils was less than 2% of that seen with opsonized zymosan stimulation, and only several-fold greater than that of resting cells. The failure to detect O2- in the latex-stimulated neutrophils was due neither to latex acting as a O2- scavenger nor to its interference with the O2- - forming system of the neutrophil. An intracellular site of O2- generation could not be demonstrated. NADPH oxidase activity in cells exposed to latex particles was only 10% of that seen in cells comparably activated with opsonized zymosan. Latex particles have the unusual property of stimulating the respiratory burst of the human neutrophil without the extracellular release of O2-. The potential physiologic importance of this finding is discussed.
Interannual Variability of the 500 mb Zonal Mean Flow in the Southern Hemisphere

Abstract An analysis has been made of the means and variability of the 500 mb field in the Southern Hemisphere, with accent on the zonal means of geopotential height and westerly wind. Long-term means for May 1972-January 1978 are significantly different from previous analyses and reveal very large and significant trends in geopotential height, especially over Antarctica. Standard deviations of zonal winds and heights are larger than in the Northern Hemisphere and, in contrast to the Northern Hemisphere, are lowest in winter. Temporal variations in the zonal mean component of the flow are very pronounced and some aspects of the very anomalous flow in December 1976 are documented. Interannual variations show a remarkable quasi-biennial fluctuation in the zonal mean fields with a systematic progression of the anomalies from low to high latitudes. These are correlated with the quasi-biennial oscillation in the equatorial stratosphere.
Structure, Function, and Evolution of Biogenic Amine-binding Proteins in Soft Ticks

Two highly abundant lipocalins, monomine and monotonin, have been isolated from the salivary gland of the soft tick Argas monolakensis and shown to bind histamine and 5-hydroxytryptamine (5-HT), respectively. The crystal structures of monomine and a paralog of monotonin were determined in the presence of ligands to compare the determinants of ligand binding. Both the structures and binding measurements indicate that the proteins have a single binding site rather than the two sites previously described for the female-specific histamine-binding protein (FS-HBP), the histamine-binding lipocalin of the tick Rhipicephalus appendiculatus. The binding sites of monomine and monotonin are similar to the lower, low affinity site of FS-HBP. The interaction of the protein with the aliphatic amine group of the ligand is very similar for the all of the proteins, whereas specificity is determined by interactions with the aromatic portion of the ligand. Interestingly, protein interaction with the imidazole ring of histamine differs significantly between the low affinity binding site of FS-HBP and monomine, suggesting that histamine binding has evolved independently in the two lineages. From the conserved features of these proteins, a tick lipocalin biogenic amine-binding motif could be derived that was used to predict biogenic amine-binding function in other tick lipocalins. Heterologous expression of genes from salivary gland libraries led to the discovery of biogenic amine-binding proteins in soft (Ornithodoros) and hard (Ixodes) tick genera. The data generated were used to reconstruct the most probable evolutionary pathway for the evolution of biogenic amine-binding in tick lipocalins.
Single-photon propagation through dielectric bandgaps

Theoretical models of photon traversal through quarter-wave dielectric stack barriers that arise due to Bragg reflection predict the saturation of the propagation time with the barrier length, known as the Hartman effect. This saturation is sensitive to the addition of single dielectric layers, varying significantly from sub-luminal to apparently super-luminal and vice versa. Our research tests the suitability of photonic bandgaps as an optical model for the tunneling process. Of particular importance is our observation of subtle structural changes in dielectric stacks drastically affecting photon traversal times, allowing for apparent sub- and super-luminal effects. We also introduce a simple model to link HOM visibility to wavepacket distortion that allows us to exclude this as a possible cause of the loss of contrast in the barrier penetration process.
Cystatin C Mutation in an Elderly Man With Sporadic Amyloid Angiopathy and Intracerebral Hemorrhage

Background Cerebral amyloid angiopathy (CAA) with intracerebral hemorrhage (ICH) occurs both sporadically and as a result of mutations in either cystatin C or the amyloid precursor protein. ICH due to cystatin C mutations typically occurs in young people of Icelandic origin. Case Description We report a case of sporadic CAA with ICH in an elderly Croatian man with a mutation in cystatin C identical to that found in Icelandic hereditary cerebral hemorrhage with amyloidosis. Conclusions This is the first case report of sporadic CAA associated with the same mutation causing hereditary cerebral hemorrhage with amyloidosis of the Icelandic type. Sporadic CAA may thus be associated with genetic mutations in some patients. The frequency of these mutations is yet to be determined.
Pentoxifylline reduces injury to isolated lungs perfused with human neutrophils.

Neutrophils and neutrophil-derived oxidants have been implicated in the development of acute lung injury such as that seen in the adult respiratory distress syndrome (ARDS), in bronchopulmonary dysplasia (BPD), and in animal models of lung injury, including the isolated perfused lung. Both neutrophil-derived oxidant production and retention of neutrophils in the lung are required for injury in this model. Pentoxifylline can reduce lung injury from sepsis in the guinea pig and endotoxin-induced neutrophil sequestration and lung injury in the dog. It is also known to increase neutrophil deformability, which may affect retention in the pulmonary microvasculature. We evaluated neutrophil oxidant production, retention in isolated lungs, and neutrophil-mediated acute lung injury after phorbol myristate acetate (PMA) in the presence of pentoxifylline. Pentoxifylline (2 mM) significantly reduced Superoxide anion and hydrogen peroxide production in vitro from PMA-stimulated neutrophils when pentoxifylline was dire...
Identification of School Bullies by Survey Methods

How can middle school counselors identify bullies? This study compared two methods of identifying bullies in a sample of 386 middle school students. A peer nomination survey identified many more bu...
A Linear Analysis of the Interaction Between the Atmosphere and an Underlying Compliant Plant Canopy

We summarise the results of a theoretical investigation of the interaction between the lower atmosphere and a compliant plant canopy. In this investigation, plant collisions were modelled as simple spring or dashpot interactions between adjacent plants. Linearised canopy models show that dashpot collisions and spring collisions are effective at reducing the amplitude of a canopy’s response to wind forcing, and may thus serve to stabilise plants against lodging and windthrow. Both types of collisions can also induce shifts in the stand resonance frequency and may thus serve to stabilise stands even further by shifting the canopy resonance frequency away from the most energetic frequencies in the atmospheric power spectrum. We also include a linear analysis of the shear layer instability over a waving canopy, and show that canopy drag has a strong effect on the instability. However, stem stiffness and inter-plant collisions have only minor effects on the wavenumber, growth rate, and frequency of the most unstable wave.
The fine structure of neuroglia in the central nervous system of Nereid polychaetes.

The principal supportive elements of the nereid central nervous system are non-neuronal cells that are referred to as supportive glia. Supportive glial cells form a conspicuous cortex in the nerve cord. The inner region of this cortex consists of closely packed processes and cell bodies of fibrous supportive glial cells that are arranged in concentric layers around the perimeter of the neuropile. The fibrous appearance of the glial cells results from dense bundles of cytoplasmic filaments. Many fibrous glial processes penetrate the neuropile and ramify among the neuronal elements. Larger, irregularly shaped cells are the chief supportive glial elements of the peripheral region of the cortex where they line the stromal sheath (neural lamella) and invest the neuronal perikarya with extensive concentric systems of lamellate processes. These glial cells usually possess a relatively undifferentiated cytoplasm with scattered glycogen granules, but occasionally have a well developed Golgi apparatus, endoplasmic reticulum and densely packed particulate glycogen. The supportive glia exhibits numerous desmosomes as well as 5-layered (“tight”) and 7-layered (“gap”) junctions. Interspersed among the supportive glial cells are non-neuronal cells referred to as granulocytes. These cells have abundant large, granular inclusions, electron lucent vesicles, plasmalemmal infoldings and microtubules. The granulocytes may be derived from undifferentiated glial cells or may represent coelomocytes that have invaded the nervous tissue.
The tmRNA Website: invasion by an intron

tmRNA (also known as 10Sa RNA or SsrA) plays a central role in an unusual mode of translation, whereby a stalled ribosome switches from a problematic mRNA to a short reading frame within tmRNA during translation of a single polypeptide chain. Research on the mechanism, structure and biology of tmRNA is served by the tmRNA Website, a collection of sequences for tmRNA and the encoded proteolysis-inducing peptide tags, alignments, careful documentation and other information; the URL is http://www.indiana.edu/~tmrna. Four pseudoknots are usually present in each tmRNA, so the database is rich with information on pseudoknot variability. Since last year it has doubled (227 tmRNA sequences as of September 2001), a sequence alignment for the tmRNA cofactor SmpB has been included, and genomic data for Clostridium botulinum has revealed a group I (subgroup IA3) intron interrupting the tmRNA T-loop.
Homonuclear and Heteronuclear NMR Studies of a Statherin Fragment Bound to Hydroxyapatite Crystals

Acidic proteins found in mineralized tissues act as nature's crystal engineers, where they play a key role in promoting or inhibiting the growth of minerals such as hydroxyapatite (HAP), Ca10(PO4)6(OH)2, the main mineral component of bone and teeth. Key to understanding the structural basis of protein-crystal recognition and protein control of hard tissue growth is the nature of interactions between the protein side chains and the crystal surface. In an earlier work we have measured the proximity of the lysine (K6) side chain in an SN-15 peptide fragment of the salivary protein statherin adsorbed to the Phosphorus-rich surface of HAP using solid-state NMR recoupling experiments. 15N(31P) rotational echo double resonance (REDOR) NMR data on the side-chain nitrogen in K6 gave rise to three different models of protein-surface interaction to explain the experimental data acquired. In this work we extend the analysis of the REDOR data by examining the contribution of interactions between surface phosphorus atoms to the observed 15N REDOR decay. We performed 31P-31P recoupling experiments in HAP and (NH4)2HPO4 (DHP) to explore the nature of dipolar coupled 31P spin networks. These studies indicate that extensive networks of dipolar coupled 31P spins can be represented as stronger effective dipolar couplings,more » the existence of which must be included in the analysis of REDOR data. We carried out 15N(31P) REDOR in the case of DHP to determine how the size of the dephasing spin network influences the interpretation of the REDOR data. Although use of an extended 31P coupled spin network simulates the REDOR data well, a simplified 31P dephasing system composed of two spins with a larger dipolar coupling also simulates the REDOR data and only perturbs the heteronuclear couplings very slightly. The 31P-31P dipolar couplings between phosphorus nuclei in HAP can be replaced by an effective dipolar interaction of 600 Hz between two 31P spins. We incorporated this coupling and applied the above approach to reanalyze the 15N(31P) REDOR of the lysine side chain approaching the HAP surface and have refined the binding models proposed earlier. We obtain 15N-31P distances between 3.3 and 5 ? from these models that are indicative of the possibility of a lysine-phosphate hydrogen bond.« less
Spontaneous deposition of gold nanoparticle nanocomposite on polymer surfaces through sol–gel chemistry

A aminosilica nanocomposite layer containing a monolayer of gold nanoparticles (d = 18-22 nm) with a well-defined spacing was spontaneously deposited on an unmodified polystyrene surface via a sol-gel reaction when the reduction reaction was carried out under 1:8 molar ratio (gold(III):aminosilane). The amount of aminosilica and spacing between gold nanoparticles were found to be a function of the aminosilane:water molar ratio, which contributes to the plasmonic property of the films with its absorption wavelength ranging between 701 and 548 nm. Furthermore, the nanocomposite film that consists of a monolayer of nanoparticles in aminosilica has also been deposited on the surface of polystyrene beads. This core-shell structure was found capable of storing electrostatic charges and forming a well-separated 2D array.
On the choice of variance for the log rank test

SUMMARY The log rank test is widely used for comparison of survival curves. This paper examines various estimators for the variance of the log rank test statistic. These include the Mantel-Haenszel variance, the permutation variance of Peto & Peto and several newly proposed estimators. The results generalize to a class of test statistics proposed by Tarone & Ware. The log rank test is widely used for comparison of survival curves. There are two versions of the test which differ in the choice of variance for the same test statistic T. These are the Mantel-Haenszel variance, an estimate of var (T) which is unbiased independently of differences in censoring, and the permutation variance of Peto & Peto (1972), for which the variance is computed under the assumption of equal censoring. This paper examines the choice of variance. It is observed that for equal sample sizes the Mantel-Haenszel variance tends to underestimate the true variance when T is large in absolute value. As this is the situation where rejection of the null hypothesis is to be seriously considered, it appears that the true type I error will tend to be higher than that assumed, and the reported P value will tend to be too low. This phenomena is discussed also by Morton (1978). In ? 4, it is shown that under equal sample sizes the permutation variance tends to overestimate the true variance when censoring is unequal. It thus appears prudent to use the permutation variance rather than the Mantel-Haenszel variance in assessing significance. In ? 5 alternative variance estimators are proposed. The results immediately generalize to a class of test statistics proposed by Tarone & Ware (1977). This point is discussed in ? 6.
Evaluating a Transitional Living Program for Homeless, Former Foster Care Youth.

The goals of this study were to (a) assess the outcomes of former foster care youth using transitional living programs and (b) compare outcomes achieved by former foster care youth who participated in an employment training program with similar youth who did not. The study sampled 23 former foster care youth using transitional living services in Northern California. Hourly wage, money saved, and employment status outcomes were examined at discharge, and housing outcomes were examined 6 months post discharge. Variables that demonstrated improvement post intervention include hourly wage, housing situation, employment, and money saved. At a 6-month follow-up, 90% of youth with known housing situations were in permanent, stable housing. Comparing youth with employment training and those without on hourly wage, youth with training had significantly higher hourly wages. Transitional living and employment training programs may be effective interventions for former foster care youth with few resources.
Tangential ligand-induced strain in icosahedral Au13.

A quantitative comparison of first principles calculations with extended X-ray absorption fine structure and transmission electron microscopy measurements provides strong evidence that Au13 nanocrystals are stabilized in a slightly distorted icosahedral structure by on-top phosphine ligands and a combination of on-top and bridging thiol ligands. Importantly, the ligands change the icosahedral strain (i.e., the radial−tangential bond length ratio) significantly, with the tangential bonds within the Au core exhibiting much more disorder than the radial ones.
Function and clustered expression of MaxiK channels in cerebral myocytes remain intact with aging

The incidence of stroke increases significantly in the aging population where stroke related deaths boost at >75 years and survivors are often permanently disabled. Aging is known to decrease cerebral blood flow likely due to an increase in arterial tone. Although MaxiK channels are key regulators of cerebral arterial tone their pattern of expression and function in cerebral blood vessels during aging is unknown. Using specific antibodies against the alpha-subunit of MaxiK channels and current recordings, we now demonstrate that in aging cerebral myocytes, MaxiK channels remain healthy. Furthermore, we show for the first time that in the vasculature, MaxiK channels are expressed in clusters. Clusters have an estimated radius of approximately 200 nm in young rats (3-5 month old Fisher 344 rats) which remains normal in old (25-30 month rats) cerebral myocytes. Consistent with a healthy MaxiK channel expression in old cerebral arteries, MaxiK current density, kinetics and Ca(2+) sensitivity were practically identical in young and old myocytes. Sensitivity to nanomolar concentrations of dehydrosoyasaponin-I that activates channels formed by alpha and beta subunits is also the same in young and old myocytes. These results demonstrate that MaxiK channels maintain normal expression during cerebral aging which is in sharp contrast to our previous finding of loss of expression in aging coronary arteries. It seems therefore, that cerebral myocytes have developed a protective anti-aging mechanism leading to the continued expression of MaxiK channels.
Finite element solution of three-dimensional turbulent flows applied to mold-filling problems

This paper presents a finite element solution algorithm for three-dimensional isothermal turbulent flows for mold-filling applications. The problems of interest present unusual challenges for both the physical modelling and the solution algorithm. High-Reynolds number transient turbulent flows with free surfaces have to be computed on complex three-dimensional geometries. In this work, a segregated algorithm is used to solve the Navier–Stokes, turbulence and front-tracking equations. The streamline–upwind/Petrov–Galerkin method is used to obtain stable solutions to convection-dominated problems. Turbulence is modelled using either a one-equation turbulence model or the κ–e two-equation model with wall functions. Turbulence equations are solved for the natural logarithm of the turbulence variables. The change of dependent variables allows for a robust solution algorithm and good predictions even on coarse meshes. This is very important in the case of large three-dimensional applications for which highly refined meshes result in untreatable large numbers of elements. The position of the flow front in the mold cavity is computed using a level set approach. Finally, equations are integrated in time using an implicit Euler scheme. The methodology presents the robustness and cost effectiveness needed to tackle complex industrial applications. Copyright © 2000 John Wiley & Sons, Ltd.
The relative importance of patients’ decisional control preferences and experiences

Objective: Patients’ role in treatment decision-making can influence psychosocial and health-related outcomes (i.e. satisfaction, felt respect, adherence). We examined decisional control in a surgical context, identifying correlates of patients’ preferences and experiences.Design: 380 patients and 7 surgeons were surveyed during initial surgical consultation visits in a low-income outpatient clinic.Measures: Patients reported preferences for (pre-consultation) and experiences of (post-consultation) decisional control, demographics, satisfaction with care, and adherence to treatment recommendations. Surgeons rated patients’ health status.Results: Preferences for and experiences of decisional control were unrelated, suggesting significant preference–experience misalignment. However, this misalignment did not appear to be consequential for patient outcomes. Rather, more decisional control, regardless of patients’ preferences, predicted greater satisfaction with care and greater self-reported adherence as ass...
Modulation of odor-induced increases in [Ca2+]i by inhibitors of protein kinases A and C in rat and human olfactory receptor neurons

Protein kinases A and C have been postulated to exert multiple effects on different elements of signal transduction pathways in olfactory receptor neurons. However, little is known about the modulation of olfactory responses by protein kinases in intact olfactory receptor neurons. To further elucidate the details of the modulation of odorant responsiveness by these protein kinases, we investigated the action of two protein kinase inhibitors: H89, an inhibitor of protein kinase A, and N-myristoylated EGF receptor, an inhibitor of protein kinase C, on odorant responsiveness in intact olfactory neurons. We isolated individual olfactory neurons from the adult human and rat olfactory epithelium and measured responses of the isolated cells to odorants or biochemical activators that have been shown to initiate cyclic AMP or inositol 1,4,5-trisphospate production in biochemical preparations. We employed calcium imaging techniques to measure odor-elicited changes in intracellular calcium that occur over several seconds. In human olfactory receptor neurons, the protein kinase A and C inhibitors affected the responses to different sets of odorants. In rats, however, the protein kinase C inhibitor affected responses to all odorants, while the protein kinase A inhibitor had no effect. In both species, the effect of inhibition of protein kinases was to enhance the elevation and block termination of intracellular calcium levels elicited by odorants. Our results show that protein kinases A and C may modulate odorant responses of olfactory neurons by regulating calcium fluxes that occur several seconds after odorant stimulation. The effects of protein kinase C inhibition are different in rat and human olfactory neurons, indicating that species differences are an important consideration when applying data from animal studies to apply to humans.
Induction of mesoderm by a viral oncogene in early Xenopus embryos

During frog embryogenesis, mesoderm is specified in the equatorial region of the early embryo by a signal from the vegetal hemisphere. Prospective ectodermal cells dissected from the animal hemisphere can be respecified to form mesodermal tissues by recombination with vegetal tissue or by treatment with any of several polypeptide growth factors or growth factor-like molecules. Together with the discovery that several developmental mutations in Drosophila are in genes with significant homology to mammalian mitogens and oncogenes, these observations suggest that early developmental signals may use similar transduction pathways to mitogenic signals characterized in cultured mammalian cells. Whether mesoderm can be induced by activation of intracellular signal transduction pathways implicated in mitogenesis and oncogenesis has been investigated with the viral oncogene polyoma middle T. Microinjection of middle T messenger RNA into early embryos results in the respecification of isolated prospective ectodermal tissue to form characteristic mesodermal structures. Middle T in frog blastomeres appears to associate with cellular activities similar to those observed in polyoma-transformed mouse cells, and transformation-defective middle T mutants fail to induce mesoderm. These results suggest that early inductive signals and mitogenic and oncogenic stimuli may share common signal transduction pathways.
Cold neutron production.

We disagree with the statements in Andrew Lawler's article “U.S. neutron scientists settle for less” concerning the availability of cold neutrons at pulsed neutron sources (PSs) (News & Comment, [9 Aug., p. 728][1]) that cold neutron production is merely a “theoretical possibility” and that the associated technology lags behind that for reactors. Because pulsed sources produce high fluxes of “hot” neutrons in a natural way, perhaps not everyone is aware of the success with which cold neutrons are being produced and exploited at PSs. It is actually easier to produce cold neutrons at a PS than at a reactor. The overall heat load is much less for the same peak neutron flux, and the required moderators are small in dimension and can usually be inserted into the neighborhood of the spallation target in a simple way. Thus, a moderator change can be accomplished in a few weeks. The cold moderator design, construction, and installation can be done within normal operating budgets. This is in contrast to the case for reactors, where the installation of a cold moderator is a major project requiring separate funding and usually a significant shutdown for installation. Moreover, the spectral and pulse characteristics can be tailored to fit applications. The existing pulsed spallation neutron sources owe much of their success to cold moderator technology. The scientific problems that have been addressed have been in the same areas as those addressed using reactor-based cold sources. The areas in question, as is typical for neutron beam exploitation in general, are extraordinarily diverse and range from surface science and chemical spectroscopy to magnetism. The possibilities inherent in the time structure of PS cold moderator performance represent opportunities for optimization beyond those of steady-source moderators that are still being explored. [1]: /lookup/volpage/274/728
Conical propagation of a surface polariton across a grating

By the use of the homogeneous form of the reduced Rayleigh equation for the electromagnetic field above and on a two-dimensional rough surface we obtain the dispersion relation for a surface polariton propagating across a classical diffraction grating when the sagittal plane is not perpendicular to the generators of the surface. This dispersion relation is exact within the domain of validity of the Rayleigh hypothesis upon which it is based. It is solved numerically, and dispersion curves are determined for several directions of propagation of the surface polariton for three different choices for the grating profile function. Particular attention is paid to the dependence on the direction of propagation of the position and width of the gap in the surface polariton dispersion curve that occurs at the boundary of the first Brillouin zone defined by the periodicity of the grating. The results obtained are compared with those of a recent experimental determination of this gap.
The Pervasiveness and Persistence of the Feminine Beauty Ideal in Children's Fairy Tales:

This study advances understanding of how a normative feminine beauty ideal is maintained through cultural products such as fairy tales. Using Brothers Grimm's fairy tales, the authors explore the extent and ways in which “feminine beauty” is highlighted. Next, they compare those tales that have survived (e.g., Cinderella, Snow White, Sleeping Beauty) with those that have not to determine whether tales that have been popularized place more emphasis on women's beauty. The findings suggest that feminine beauty is a dominant theme and that tales with heavy emphases on feminine beauty are much more likely to have survived. These findings are interpreted in light of changes in women's social status over the past 150 years and the increased importance of establishing forms of normative social control to maintain a gender system.
Self-interests and Group-Interests in Employee Involvement Programs: A Case Study*

What happens in a unionized setting when a participatory management system is adopted? This question is examined based on a field study of a union manufacturing facility that has been operating under a gainsharing system for four years. As suggested by the political science literature on transforming political systems from authoritarian rule to democracies, the events resemble a complicated chess game among management, union officers, and union members pursuing their self-interests or group-interests during and after the transitional process. Although gainsharing bonuses have been minimal, the democratization of organizational structures and relationships has generated multiple beneficial organizational and individual outcomes for management and union members.
Coronary vasoactivity of acetate in dog and guinea-pig.

This study compares the coronary vasoactivity of acetate in the blood-perfused heart of the open-chest dog and in the buffer-perfused guinea-pig heart. In the dog acetate is a weak but probably fully efficacious coronary agonist. Direct intracoronary infusions of isosmolar Na acetate caused dose-dependent coronary vasodilation and decreased transcoronary O2 extraction, resulting in an increase in cardiac O2 usage of up to 40%. Acetate raised coronary flow to at least 50% above control in 63 of 67 dogs but caused maximum coronary vasodilation (400% of control) in only 39 of the 67. The frequency distribution of the acetate EC-20 decreased monotonically from a mode at 6 mM, suggesting a single population of animals characterized by a rather wide range of sensitivity to acetate. Theophylline antagonized acetate vasodilation, in support of the idea that adenosine mediates the coronary effects of acetate. In the guinea-pig heart, acetate in concentrations up to 10 mM caused minimal increases in coronary flow that were completely accounted for by the small change in O2 usage that resulted from switching from glucose to acetate the main energy source. Acetate (10 mM) elicited a small release of adenosine and its degradation products.
Electronic Tuning, Amplitude Modulation of Lasers by a Computer-Controlled Acousto-optic Tunable Filter

A novel, compact, all-solid-state, computer-controlled acousto-optic tunable filter (AOTF) which has no moving parts has been developed. The filter can be successfully used not only for the rapid tuning and amplitude-modulation of the multiwavelength laser beam but also for the stabilization of the power of the diffracted beam regardless of whether it is a continuous single wavelength or a modulated multiwavelength beam. The potential applications of this filter to the spectrochemical methods of analyses are discussed.
Fluorescence and phosphorescence of quinoxaline vapor

Abstract Fluorescence and phosphorescence has been detected from quinoxaline vapor using excitation from a high pressure mercury arc. The fluorescent emission originates near 365 nm and shows several vibronic bands. Under similar experimental conditions we have also observed a highly structured phosphorescent emission. The latter emission has been analyzed in terms of the fundamental vibrational frequencies of the ground state.