cssi/SciSciGPT-SciSciNet huggingface dataset:
Dynamical fluctuations in dense granular flows.

We have made measurements of force and velocity fluctuations in a variety of dense, gravity-driven granular flows under flow conditions close to the threshold of jamming. The measurements reveal a microscopic state that evolves rapidly from entirely collisional to largely frictional, as the system is taken close to jamming. On coarse-grained time scales, some descriptors of the dynamics—such as the probability distribution of force fluctuations, or the mean friction angle—do not reflect this profound change in the micromechanics of the flow. Other quantities, such as the frequency spectrum of force fluctuations, change significantly, developing low-frequency structure in the fluctuations as jamming is approached. We also show evidence of spatial structure, with force fluctuations being organized into local collision chains. These local structures propagate rapidly in the flow, with consequences far away from their origin, leading to long-range correlations in velocity fluctuations.
Cytokineplasts from human blood polymorphonuclear leukocytes. Lack of oxidase activity and extended functional longevity.

Cytokineplasts (CKPs) are membrane-bounded, anucleate, granule-poor cytoplasmic fragments, induced from PMNs by brief heat (45°C, 9 min), which retain motile function including chemotaxis and phagocytosis. CKPs can respond to repeated chemotactic stimuli even after having been held overnight at room temperature, and hence “outiive” control PMNs, We now report that adherent CKPs lack significant oxidase activity, as measured by reduction of nitroblue tetrazolium (NBT) dye, (1)5 min after heat, when they are often still attached to their parent PMNs (which generally do not reduce NBT either); (2) later on, when they are free; and (3) when cells have been pretreated on endotoxin-coated substrata or with phorbol myristate acetate (PMA); both pretreatments cause the large majority of adherent control PMNs to reduce NBT. Moreover, cells harvested from glass just after heat lack the normal increase in oxygen consumption seen on stimulation with PMA or with heat-killed staphylococci. PMA-stimulated respiratory burst activity was not restored to heated cells by exogenous NADPH. Thus, heat applied to normal PMNs can dissociate motile function from oxidase activity; in this respect CKPs resemble PMNs in chronic granulomatous disease. The apparent increased functional stability of CKPs may indicate that normal PMNs are not immune to their own oxidative killing mechanism.
Separation and detection of acidic and neutral impurities in illicit heroin via capillary electrophoresis

The separation and detection of acidic and neutral impurities in illicit heroin using capillary electrophoresis (CE) is described. Separations were achieved using charged cyclodextrin modified micellar electrokinetic capillary chromatography. The use of the anionic β-cyclodextrin sulfobutyl ether 1V in combination with sodium dodecyl sulfate significantly increased resolution. Improved selectivity and/or sensitivity in detection was obtained using photodiode array ultraviolet and laser-induced fluorescence detection. The phenanthrene-like heroin impurities exhibit high native fluorescence under krypton-fluoride laser excitation (248 nm). The limit of detection by laser-induced fluorescence detection for one of these solutes (acetylthebaol) is 1.8 ng/ml, 500 times more sensitive than UV. This methodology is applicable to analysis of both crude and refined heroin.
How and when is dual trading irrelevant

Within a general model of speculative trade, we derive the aggregate consequences of dual traders who process retail liquidity trades and trade on their own account. We prove that dual trading reduces total expected speculator profits unless speculators process all liquidity trade and trade with the same intensity on liquidity trade. In contrast, dual trading does not affect the information content of prices. We show how results generalize when we endogenize (a) speculator information via costly information acquisition about fundamentals or costly processing of liquidity trade, and (b) liquidity trader motives and welfare via endowment shocks.
Structural and spectroscopic studies of nickel(II) complexes with a library of Bis(oxime)amine-containing ligands.

A library of tripodal amine ligands with two oxime donor arms and a variable coordinating or noncoordinating third arm has been synthesized, including two chiral ligands based on l-phenylalanine. Their Ni(II) complexes have been synthesized and characterized by X-ray crystallography, UV−vis absorption, circular dichroism, and FTIR spectroscopy, mass spectrometry, and room-temperature magnetic susceptibility. At least one crystal structure is reported for all but one Ni/ligand combination. All show a six-coordinate pseudo-octahedral coordination geometry around the nickel center, with the bis(oxime)amine unit coordinating in a facial mode. Three distinct structure types are observed: (1) for tetradentate ligands, six-coordinate monomers are formed, with anions and/or solvent filling out the coordination sphere; (2) for tridentate ligands, six-coordinate monomers are formed with NiII(NO3)2, with one monodentate and one bidentate nitrate filling the remaining coordination positions; (3) for tridentate ligan...
The Pervasive 2007 Workshops

Pervasive 2007 hosted an incredible full day of workshops before the main conference. One-hundred twenty enthusiastic participants in eight great workshops discussed experiences and ideas on particular aspects of pervasive computing with like-minded researchers and practitioners. The variety of projects presented demonstrated how truly interdisciplinary the Pervasive conference has become.
Influenza Susceptibility, Severity, and Shedding in HIV-Infected Adults: A Review of the Literature

Influenza is a common cause of respiratory illness in adults infected with human immunodeficiency virus (HIV), but current knowledge about seasonal and 2009 H1N1 pandemic influenza A (H1N1pdm) virus infections in HIV-infected persons is limited. In this paper, we review the existing literature regarding influenza susceptibility, severity, and shedding in HIV-infected adults. Data show HIV infection does not significantly increase susceptibility to influenza. AIDS is associated with greater seasonal influenza-related morbidity and mortality, but the risk associated with HIV infection among those with less immune suppression is largely unknown. Immunologic compromise has been shown to increase the magnitude and duration of influenza virus shedding; however, these studies are limited within HIV-infected populations. With regards to H1N1pdm, data are even more limited. Reports raise concern of increased severity among HIV-infected persons, although this may be driven by other comorbid illnesses. Prospective studies are needed among HIV-infected persons to more definitively investigate influenza susceptibility, severity, and shedding.
Aspects of Meson Spectroscopy with N̅N Annihilation

We focus on the potentialities of nucleon-antinucleon (NN) annihilation as a means of producing new mesonic states. The case for the existence of quasinuclear NN bound states is discussed in detail. Strong evidence for a 2++(0+) state of this type has been obtained at LEAR in annihilation from the p-wave (L = 1) NN system, in support of earlier sightings of this object in L = 0 annihilation at Brookhaven. In the next generation of LEAR experiments, the emphasis shifts to the search for mesons containing dynamical excitations of the gluonic field, namely glueballs and hybrids (QQg). We discuss some features of the masses, decay branching ratios and production mechanisms for these states, and suggest particular NN annihilation channels which are optimal for their discovery.
Models of CP violation exclusively via neutral scalar exchange

I suggest a two-Higgs-doublet model in which CP violation is mediated only by the neutral Higgs bosons, via the mechanism of scalar-pseudoscalar mixing. In this model there is no CP violation in the exchange of either W bosons or charged Higgs bosons. The model has only two basic CP-violating quantities. I remark that other models of this kind, but with more than two Higgs doublets, may also be built.
The development of small molecule angiotensin IV analogs to treat Alzheimer's and Parkinson's diseases.

Abstract Alzheimer's (AD) and Parkinson's (PD) diseases are neurodegenerative diseases presently without effective drug treatments. AD is characterized by general cognitive impairment, difficulties with memory consolidation and retrieval, and with advanced stages episodes of agitation and anger. AD is increasing in frequency as life expectancy increases. Present FDA approved medications do little to slow disease progression and none address the underlying progressive loss of synaptic connections and neurons. New drug design approaches are needed beyond cholinesterase inhibitors and N-methyl- d -aspartate receptor antagonists. Patients with PD experience the symptomatic triad of bradykinesis, tremor-at-rest, and rigidity with the possibility of additional non-motor symptoms including sleep disturbances, depression, dementia, and autonomic nervous system failure. This review summarizes available information regarding the role of the brain renin–angiotensin system (RAS) in learning and memory and motor functions, with particular emphasis on research results suggesting a link between angiotensin IV (AngIV) interacting with the AT 4 receptor subtype. Currently there is controversy over the identity of this AT 4 receptor protein. Albiston and colleagues have offered convincing evidence that it is the insulin-regulated aminopeptidase (IRAP). Recently members of our laboratory have presented evidence that the brain AngIV/AT 4 receptor system coincides with the brain hepatocyte growth factor/c-Met receptor system. In an effort to resolve this issue we have synthesized a number of small molecule AngIV-based compounds that are metabolically stable, penetrate the blood–brain barrier, and facilitate compromised memory and motor systems. These research efforts are described along with details concerning a recently synthesized molecule, Dihexa that shows promise in overcoming memory and motor dysfunctions by augmenting synaptic connectivity via the formation of new functional synapses.
Primary intramedullary melanocytoma of the spinal cord: case report.

OBJECTIVE: The authors report 2 cases of primary intramedullary spinal melanocytomas in 2 patients who presented with lower extremity numbness and/or weakness. CLINICAL PRESENTATION: Magnetic resonance imaging of the spine, thoracic laminectomy, and histological examination revealed the diagnosis. TECHNIQUE: Microscopic and immunohistochemical analysis revealed the diagnosis of primary melanocytoma. CONCLUSION: Melanocytomas of the spine are rare lesions without distinctive imaging characteristics and pose a preoperative diagnostic challenge. A review of the relevant literature and clinical behavior of this uncommon tumor entity is provided.
Ethylene in relation to the response of roots to physical impedance

When the axial growth of bean roots (Vicia faba, L., variety Broad Windsor) was impeded by a barrier, the rate of ethylene evolution increased by as much as six times that of unimpeded controls. This high rate was maintained for at least 30 hours. When the barrier was removed, the rate of ethylene evolution decreased to near the rate of control roots. Exogenous applications of very low concentrations were inhibitory. Exogenous ethylene also resulted in an increase in radial diameter. These results indicate that ethylene evolved by bean roots in response to high mechanical resistance may act as an endogenous growth regulator.
Nitrile anions: solvent-dependent cyclizations.

Extensive cyclizations in hydrocarbon and polar solvents demonstrate a profound solvent sensitivity for intramolecular nitrile anion alkylations. SNi cyclizations enforce very precise steric constraints in the transition state, allowing correlation of the cyclization stereochemistry with the orbital orientation of the nitrile anion. Collectively the cyclizations suggest a continuum of nitrile anion transition states, varying from planar to fully pyramidal, that selectively cyclize to cis- and trans-decalins, respectively.
Gravity Sensing and Signal Transduction in Vascular Plant Primary Roots

During gravitropism, the potential energy of gravity is converted into a biochemical signal. How this transfer occurs remains one of the most exciting mysteries in plant cell biology. New experiments are filling in pieces of the puzzle. In this review, we introduce gravitropism and give an overview of what we know about gravity sensing in roots of vascular plants, with special highlight on recent papers. When plant roots are reoriented sideways, amyloplast resedimentation in the columella cells is a key initial step in gravity sensing. This process somehow leads to cytoplasmic alkalinization of these cells followed by relocalization of auxin efflux carriers (PINs). This changes auxin flow throughout the root, generating a lateral gradient of auxin across the cap that upon transmission to the elongation zone leads to differential cell elongation and gravibending. We will present the evidence for and against the following players having a role in transferring the signal from the amyloplast sedimentation into the auxin signaling cascade: mechanosensitive ion channels, actin, calcium ions, inositol trisphosphate, receptors/ligands, ARG1/ARL2, spermine, and the TOC complex. We also outline auxin transport and signaling during gravitropism.
In vitro oxidation of [3-14C]acetoacetate in brain cortex from hibernating hamsters and ground squirrels.

1. 1. A comparison was made of the utilization of acetoacetate in brain tissue from hibernating and nonhibernating hamsters, Mesocricetus auratus, and ground squirrels, Citellus tridecemlineatus. 2. 2. In vitro oxidation of [3-14C] acetoacetate was used as an index of ketone utilization. 3. 3. Oxidative metabolism of acetoacetate in cerebral tissue from both hibernating and nonhibernating hamsters and ground squirrels was evident, and at 27°C (compared with 37°C) levels were much reduced. 4. 4. Incorporation of acetoacetate in cerebral tissue from hamster was much greater than in ground squirrel in both hibernating and nonhibernating animals.
Soliton structure in crystalline acetanilide

The theory of self-trapping of amide I vibrational energy in crystalline acetanilide is studied in detail. A spectrum of stationary, self-trapped (soliton) solutions is determined and tested for dynamic stability. Only those solutions for which the amide I energy is concentrated near a single molecule were found to be stable. Exciton modes were found to be unstable to decay into solitons.
Non-additive voltammetric limiting currents of acrylamide with oxygen and hydrogen peroxide

Abstract The non-additivity of the reduction currents of acrylamide (AA) and oxygen and of AA and hydrogen peroxide is reported. These results were obtained using hydrodynamic voltammetry at a rotating mercury covered gold electrode in solutions of 0.10 M tetramethylammonium hydroxide and 0.10 M LiCl. In air and oxygen saturated solutions AA limiting currents were 6–40% lower than in oxygen free solutions. The decreases in the apparent AA currents were greater when the AA/O 2 concentration ratio was smaller. An explanation for the non-additivity is proposed. These results have implications regarding the determination of AA using electrochemical detection when the analyte concentrations are small and rigorous exclusion of oxygen is difficult, e.g., HPLC–EC.
Cancer biology and NuRD: a multifaceted chromatin remodelling complex

The nucleosome remodelling and histone deacetylase (NuRD; also known as Mi-2) complex regulates gene expression at the level of chromatin. The NuRD complex has been identified - using both genetic and molecular analyses - as a key determinant of differentiation in mouse embryonic stem cells and during development in various model systems. Similar to other chromatin remodellers, such as SWI/SNF and Polycomb complexes, NuRD has also been implicated in the regulation of transcriptional events that are integral to oncogenesis and cancer progression. Emerging molecular details regarding the recruitment of NuRD to specific loci during development, and the modulation of these events in cancer, are used to illustrate how the inappropriate localization of the complex could contribute to tumour biology.
Shear prevents detachment of target cells bound to E. coli via the bacterial adhesin, FimH

Bacteria must bind to host cells in the presence of fluid flow. While the drag force associated with fluid flow will generally act to separate noncovalent bonds, we have previously reported that shear actually enhances the binding of E. coli to model target cells such as red blood cells. Here we describe the behavior of red blood cells attached to a carpet of E. coli under shear. We show that red blood cells move along or detach from the surface-bound bacteria under low shear stress, while they move much more slowly and do not detach under moderate shear stress. Finally, at higher shear stress, they move rapidly again, but still do not detach. This behavior is reversible, so that switching from high to low shear allows cells to detach and switching from low to high shear prevents the adherent cells from detaching. These observations suggest the hypothesis that FimH-receptor bonds have two states, a low and a high affinity, and that force favors a high-affinity state.
Reading with a simulated 60-channel implant.

First generation retinal prostheses containing 50–60 electrodes are currently in clinical trials. The purpose of this study was to evaluate the theoretical upper limit (best possible) reading performance attainable with a state-of-the-art 60-channel retinal implant and to find the optimum viewing conditions for the task. Four normal volunteers performed full-page text reading tasks with a low-resolution, 60-pixel viewing window that was stabilized in the central visual field. Two parameters were systematically varied: (1) spatial resolution (image magnification) and (2) the orientation of the rectangular viewing window. Performance was measured in terms of reading accuracy (% of correctly read words) and reading rates (words/min). Maximum reading performances were reached at spatial resolutions between 3.6 and 6 pixels/char. Performance declined outside this range for all subjects. In optimum viewing conditions (4.5 pixels/char), subjects achieved almost perfect reading accuracy and mean reading rates of 26 words/min for the vertical viewing window and of 34 words/min for the horizontal viewing window. These results suggest that, theoretically, some reading abilities can be restored with actual state-of-the-art retinal implant prototypes if “image magnification” is within an “optimum range.” Future retinal implants providing higher pixel resolutions, thus allowing for a wider visual span might allow faster reading rates.
Benchmark of Space Charge Simulations and Comparison with Experimental Results for High Intensity, Low Energy Accelerators

Space charge effects are a major contributor to beam halo and emittance growth leading to beam loss in high intensity, low energy accelerators. As future accelerators strive toward unprecedented levels of beam intensity and beam loss control, a more comprehensive understanding of space charge effects is required. A wealth of simulation tools have been developed for modeling beams in linacs and rings, and with the growing availability of high-speed computing systems, computationally expensive problems that were inconceivable a decade ago are now being handled with relative ease. This has opened the field for realistic simulations of space charge effects, including detailed benchmarks with experimental data. A great deal of effort is being focused in this direction, and several recent benchmark studies have produced remarkably successful results. This paper reviews the achievements in space charge benchmarking in the last few years, and discusses challenges that remain.
Testing biomechanical strength of repairs for the mandibular angle fracture

A biomechanical model using polystyrene mandibles with simple angle fractures was developed to evaluate the structural strength of a variety of commonly used plate repairs. The model standardized the fracture location, load site, plate location, and site of deformation measurement. The only variables in the study were the nine different reconstruction types tested. Precise measurements of the deformation under load demonstrated statistically significant intra-group reproducibility for each repair. Data support previous clinical and experimental studies demonstrating the superiority of a two-plate system applied to the tension and compression regions of the mandible when compared to single-plate repairs using either noncompression (bridging) or eccentric dynamic compression plates.
Laser Communications Terminal for the X2000 Series of Planetary Missions

A new program called the Advanced Deep-Space Systems Development Program (a.k.a. X2000 Program) has been initiated to develop new cutting-edge technologies for NASA's deep-space missions in an overall flight project environment. Several technologies have been selected for development under the first delivery of the X2000 Program. Optical communications is one of those technologies. This paper provides an overview of the X2000 Program and describes the optical communications terminal that will be developed therein. The spacecraft terminal will be a multi-function instrument, capable of not only two-way communications from distances out to Europa (Jupiter), but two-way ranging, science imaging and laser altimeter reception as well. The plan for the development of the terminal is also described.
Was Darwin Wrong About Emotional Expressions

Emotional expressions have endured as a topic of profound scientific interest for over a century, in part due to Darwin’s classic volume, The Expression of Emotions in Man and Animals. Since its publication, there has been a strong, spirited debate over the origin, nature, and function of emotional expressions. In this article, I consider two basic questions: What did Darwin really write about emotional expressions, and how well does his account match the modern, conventional, “basic emotion” account? And does the scientific evidence specifically support the modern account of Darwin’s view, or are there alternative hypotheses that provide good (or even better) interpretations for the data at hand? I discuss the various ways that Darwin might be correct (and incorrect) about how emotions and their manifestations have been sculpted by natural selection.
Surface area of particle administered versus mass in determining the pulmonary toxicity of ultrafine and fine carbon black: comparison to ultrafine titanium dioxide

Nanoparticles are characterized by having a high surface area per mass. Particulate surface area has been reported to play an important role in determining the biological activity of nanoparticles. However, recent reports have questioned this relationship. This study was conducted to determine whether mass of particles or surface area of particles is the more appropriate dose metric for pulmonary toxicity studies. In this study, rats were exposed by intratracheal instillation to various doses of ultrafine and fine carbon black. At 1, 7, or 42 days post-exposure, inflammatory and cytotoxic potential of each particle type was compared on both a mass dosage (mg/rat) as well as an equal surface area dosage (cm2 of particles per cm2 of alveolar epithelium). In an additional study, the pulmonary responses to instillation of ultrafine carbon black were compared to equivalent particle surface area doses of ultrafine titanium dioxide. Ultrafine carbon black particles caused a dose dependent but transient inflammatory and cytotoxic response. On a mass basis, these responses were significantly (65 fold) greater than those for fine sized carbon black. However, when doses were equalized based on surface area of particles given, the ultrafine carbon black particles were only slightly (non-significantly) more inflammogenic and cytotoxic compared to the fine sized carbon black. At one day post-exposure, inflammatory potencies of the ultrafine carbon black and ultrafine titanium dioxide particles were similar. However, while the pulmonary reaction to ultrafine carbon black resolved with time, the inflammatory effects of ultrafine titanium dioxide were more persistent over a 42 day post-exposure period. These results indicate that for low toxicity low solubility materials, surface area of particles administered rather than mass burden of particles may be a more appropriate dose metric for pulmonary toxicity studies. In addition, ultrafine titanium dioxide appears to be more bioactive than ultrafine carbon black on an equivalent surface area of particles delivered basis.
Extended Parental Care in Communal Social Groups

Recent developments in social insect research have challenged the need for close kinship as a prerequisite for the evolution of stable group living. In a model communal bee species, Lasioglossum (Chilalictus) hemichalceum, previous allozyme work indicated that groups of cooperating adult females are not relatives. Yet at any given time, not all group members perform the risky task of foraging. We previously hypothesized that tolerance for non-foragers was a component of extended parental care, previously known only for kin based social systems. DNA microsatellites were used to study colony genetic structure in order to test this hypothesis. Microsatellite polymorphism was substantial (He = 0.775). Overall intracolony relatedness, mainly of immatures, was low but significant in nine, late season nests (r = 0.136 ± 0.023), indicating that broods contain five to six unrelated sib ships. Detailed analyses of kinship between pairs of individuals revealed that most pairs were unrelated and most related pairs were siblings. Mothers are absent for 89–91% of the developing immature females, and 97% of developing males. Alternatively, 46% of adult females had neither sibs nor offspring in their nests. These findings indicate that the extended parental care model applies broadly to both kin based and nonkin based social systems in the Hymenoptera.
A scheduling environment for steel-making processes

A practical approach is proposed to actual scheduling problems, and its application to creating daily schedules for steel-making processes is described. Cooperative scheduling is a novel paradigm in which procedures, rules, and the user cooperate to make a feasible schedule efficiently. The procedures, collectively called a scheduling engine, work as a local constraint satisfier to solve general primitive constraints. Rules that represent domain-dependent knowledge then solve the domain-specific constraints by a pattern-matching function. Finally, the user evaluates the schedule and modifies it using a user-friendly interface with direct-manipulation functions. The user interaction is therefore included in the system architecture as a global constraint satisfier. The iteration of this cycle improves the schedule until it becomes feasible. Scheplan is a scheduling environment that applies this approach to scheduling steel-making processes. >
CYP450 pharmacogenomics: a cardiology perspective

Contemporary evidence-based medicine: ideal for populations but not always the individual The contemporary practice of cardiology is based principally on clinical evidence derived from large-scale, randomized clinical trials and registry databases. The pharmaceutical agents available for the treatment of cardiovascular diseases continue to expand. However, the evidence-base for these pharmacotherapeutics was developed from population-level analyses, where the efficacy and safety of a given agent were determined by comparing the mean rates of clinical events with the standard of care or placebo. Despite the necessity of clinical trials for advancing the practice of medicine, their results do not account for the complexities surrounding an individual’s response to a drug. The intraand interindividual variability of a drug’s effect is determined, at least in part, by an individual’s pharmacokinetic (PK) and pharmacodynamic (PD) response, which can account for clinical failure or toxicity in a subset of patients. PK/PD are influenced by intrinsic (e.g., age, race, ethnicity, gender, co-morbid disease, renal and hepatic function, genetics) and extrinsic (e.g., diet, smoking, drug–drug interactions) factors. Adverse drug reactions are common, costly, and can be fatal [1]; especially in an aging population, where polypharmacy can significantly influence drug PK/PD response. Thus, a tailored pharmacotherapeutic approach would have potentially important advantages. CYP450 genetic polymorphisms: a cardiologist’s gateway to personalized medicine? The hepatic cytochrome P-450 (CYP) isoenzymes comprise an enzyme family responsible for the metabolism of approximately 75% of drugs via oxidative biotransformation [2]. There are 57 human CYPs encoded by 57 genes (and 58 pseudogenes); five (CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP3A4) are responsible for roughly 95% of the enzymatic activity [2]. Genetic variants within the genes encoding these isoenzymes strongly influence PK/PD responses [3] and can be responsible for the significant heterogeneity of responses to drugs among individuals. For cardiologists, genetic variants in CYP genes (CYP) represent a major determinant of the clinical efficacy and safety of many cardiovascular drugs and provide a unique backdrop to paint the landscape of pharmacogenetic therapy. Herein, we discuss two examples of the intersection between cardiovascular therapeutics, clopidogrel and warfarin, and the influence of CYP variants.
Discharge characteristics in cesium-seeded argon.

As part of a program investigating nonequilibrium MHD power generation, experiments were performed to study discharge characteristics in a cesium-seeded argon blowdown facility with a maximum capability in gas total temperature of 1500°K, Mach number M = 0.6 and applied magnetic field B = 22,500 gauss. The results show that an ionization instability can occur as the result of a slow ionization rate in a convective flowfield, and does not necessarily depend on the presence of a magnetic field. Discharge holding devices were fully capable of controlling the instability up to M = 0.6 with 5 = 0, but some effectiveness was lost with increasing P due to a dependence of the final channel nonequilibrium conductivity on the magnetic field and the electrode geometry without the need to consider nonuniform conductivity effects arising from discharge streamers or striations. In addition, measurements showed that an increasing magnetic field produced an increase in: the electron density recombination rate; the plasma breakdown voltage; and the plasma dissipation rate with respect to conductivity. There was also evidence of significant electron density relaxation during preionization.
Transport with spatially variable kinetic sorption: recursion formulation

A recursion formulation for the transport of linearly sorbing solutes undergoing nonequilibrium sorption is developed. Constant or spatially varying sorption kinetics can be modeled using the recursion approach. The sorption and desorption rates are modeled as two independent random processes with a prescribed mean and covariance structure with spatial variability in the rate parameters included as well. The recursion solution, in terms of the probability density function for solute travel times, is derived by specifying transition probabilities for moving between the aqueous and sorbed phases. A few simple examples are used to illustrate the approach. The computer implementation leads to a very rapid algorithm that is easily extended to cover cases beyond the basic model presented here. q 1999 Elsevier Science Ltd. All rights reserved.
Work/Family Border Theory: A New Theory of Work/Family Balance

This article introduces work/family border theory - a new theory about work/family balance. According to the theory, people are daily border-crossers between the domains of work and family. The theory addresses how domain integration and segmentation, border creation and management, border-crosser participation, and relationships between border-crossers and others at work and home influence work/family balance. Propositions are given to guide future research.
Risks of Extracorporeal Membrane Oxygenation in Patients With Coronary Artery Anomalies

Extracorporeal membrane oxygenation is widely used to support and rest the heart before or following repair of congenital cardiac lesions in children. The beneficial effects of extracorporeal membrane oxygenation for the failing myocardium are undisputed. It is often an automatic choice whenever the heart seems incapable of supporting the circulation. However, its use may prove detrimental in patients with coronary anomalies, as illustrated by the case reports presented here.
Gene Frequency Distributions Reject a Neutral Model of Genome Evolution

Evolution of prokaryotes involves extensive loss and gain of genes, which lead to substantial differences in the gene repertoires even among closely related organisms. Through a wide range of phylogenetic depths, gene frequency distributions in prokaryotic pangenomes bear a characteristic, asymmetrical U-shape, with a core of (nearly) universal genes, a “shell” of moderately common genes, and a “cloud” of rare genes. We employ mathematical modeling to investigate evolutionary processes that might underlie this universal pattern. Gene frequency distributions for almost 400 groups of 10 bacterial or archaeal species each over a broad range of evolutionary distances were fit to steady-state, infinite allele models based on the distribution of gene replacement rates and the phylogenetic tree relating the species in each group. The fits of the theoretical frequency distributions to the empirical ones yield model parameters and estimates of the goodness of fit. Using the Akaike Information Criterion, we show that the neutral model of genome evolution, with the same replacement rate for all genes, can be confidently rejected. Of the three tested models with purifying selection, the one in which the distribution of replacement rates is derived from a stochastic population model with additive per-gene fitness yields the best fits to the data. The selection strength estimated from the fits declines with evolutionary divergence while staying well outside the neutral regime. These findings indicate that, unlike some other universal distributions of genomic variables, for example, the distribution of paralogous gene family membership, the gene frequency distribution is substantially affected by selection.
Shared Winner Determination in Sponsored Search Auctions

Sponsored search auctions form a multibillion dollar industry. Search providers auction advertisement slots on search result pages to advertisers who are charged only if the end-user clicks on the advertiser's ad. The high volume of searches presents an opportunity for sharing the workrequired to resolve multiple auctions that occur simultaneously. We provide techniques for efficiently resolving sponsored search auctions involving large numbers of advertisers, with a focus on two issues: sharing work between multiple search auctions using shared aggregation and shared sort, and dealing with budget uncertainty arising from ads that have been displayed from previous auctions but have not received clicks yet.
Completion of DNA replication in Escherichia coli

The mechanism by which cells recognize and complete replicated regions at their precise doubling point must be remarkably efficient, occurring thousands of times per cell division along the chromosomes of humans. However, this process remains poorly understood. Here we show that, in Escherichia coli, the completion of replication involves an enzymatic system that effectively counts pairs and limits cellular replication to its doubling point by allowing converging replication forks to transiently continue through the doubling point before the excess, over-replicated regions are incised, resected, and joined. Completion requires RecBCD and involves several proteins associated with repairing double-strand breaks including, ExoI, SbcDC, and RecG. However, unlike double-strand break repair, completion occurs independently of homologous recombination and RecA. In some bacterial viruses, the completion mechanism is specifically targeted for inactivation to allow over-replication to occur during lytic replication. The results suggest that a primary cause of genomic instabilities in many double-strand-break-repair mutants arises from an impaired ability to complete replication, independent from DNA damage.
Inflammation associated anemia and ferritin as disease markers in SLE

Introduction In a recent screening to detect biomarkers in systemic lupus erythematosus (SLE), expression of the iron storage protein, ferritin, was increased. Given that proteins that regulate the storage, transfer and release of iron play an important role in inflammation, this study aims to determine the serum and urine levels of ferritin and of the iron transfer protein, transferrin, in lupus patients and to correlate these levels with disease activity, inflammatory cytokine levels and markers of anemia.
Work posture, workstation design, and musculoskeletal discomfort in a VDT data entry task

Self-report data on musculoskeletal discomfort were collected from several hundred VDT users in two agencies of a state government. Aspects of worker posture and workstation design were objectively assessed for 40 of the VDT users. Multiple regression analyses were used to examine the relationship between these ergonomic variables and musculoskeletal discomfort. Effects of ergonomic factors on musculoskeletal discomfort were clearly evident in the analyses. Regression models explained up to 38% of the variance in discomfort at different body sites. Of special interest was that leg discomfort increased with low, soft seat pans, suggesting that postural constraint is more important than thigh compression as a risk factor for leg discomfort in VDT work. In addition, arm discomfort increased with increases in keyboard height above elbow level, supporting arguments for low placement of the keyboard. Finally, high levels of neck and shoulder girdle discomfort observed in the study population suggest the need for further attention to the control of cervicobrachial pain syndromes in VDT work.
Impurity-Defect Complexes in Hydrogenated Amorphous Silicon

The two most outstanding features observed for dopants in hydrogenated amorphous silicon (a-Si:H) -- a shift in the Fermi level accompanied by an increase in the defect density and an absence of degenerate doping -- have previously been postulated to stem from the formation of substitutional dopant-dangling bond complexes. Using first-principles self-consistent pseudopotential calculation in conjunction with a supercell model for the amorphous network and the ability of network relaxation from the first-principles results, we have studied the electronic and structural properties of substitutional fourfold-coordinated phosphorus and boron at the second neighbor position to a dangling bond defect. We demonstrate that such impurity-defect complexes can account for the general features observed experimentally in doped a-Si:H. 16 refs., 2 figs., 1 tab.
Applying engineering and fleet detail to represent passenger vehicle transport in a computable general equilibrium model

Abstract A well-known challenge in computable general equilibrium (CGE) models is to maintain correspondence between the forecasted economic and physical quantities over time. Maintaining such a correspondence is necessary to understand how economic forecasts reflect, and are constrained by, relationships within the underlying physical system. This work develops a method for projecting global demand for passenger vehicle transport, retaining supplemental physical accounting for vehicle stock, fuel use, and greenhouse gas (GHG) emissions. This method is implemented in the MIT Emissions Prediction and Policy Analysis Version 5 (EPPA5) model and includes several advances over previous approaches. First, the relationship between per-capita income and demand for passenger vehicle transport services (in vehicle-miles traveled, or VMT) is based on econometric estimates and modeled using quasi-homothetic preferences. Second, the passenger vehicle transport sector is structured to capture opportunities to reduce fleet-level gasoline use through the application of vehicle efficiency or alternative fuel vehicle technologies, introduction of alternative fuels, or reduction in demand for VMT. Third, alternative fuel vehicles (AFVs) are represented in the EPPA model. Fixed costs as well as learning effects that could influence the rate of AFV introduction are captured explicitly. This model development lays the foundation for assessing policies that differentiate based on vehicle age and efficiency, alter the relative prices of fuels, or focus on promoting specific advanced vehicle or fuel technologies.
Decitabine in the treatment of myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a group of heterogeneous clonal hematopoietic stem cell disorders characterized by ineffective hematopoiesis, peripheral blood cytopenias and a propensity to transform into acute myeloid leukemia. There are few treatment options available for patients with MDS. Studies into the molecular biology of MDS have demonstrated abnormal patterns of DNA methylation that lead to silencing of tumor-suppressor genes. Hypomethylating agents are compounds that have the potential to reverse the aberrant DNA methylation and increase the expression of silenced genes, leading to cellular differentiation and/or apoptosis. Decitabine is a cytidine analogue that has activity as a hypomethylating agent and has been evaluated in the therapy of patients with high-risk MDS. Several studies have confirmed the clinical activity of low-dose decitabine in patients with high-risk MDS, leading to responses in approximately 50% of patients, with low treatment-related mortality. Responses have even been seen in patients with high-risk cytogenetic abnormalities, and some studies have demonstrated increased re-expression of genes that were previously silenced by hypermethylation, such as CDKN2B/p15INK4B. There are still some issues concerning the ideal dose and schedule of decitabine for treating patients with MDS. This article focuses on the most recent clinical studies of decitabine for therapy of MDS.
Tea consumption and the reduced risk of colon cancer -- results from a national prospective cohort study.

Objective:This study examines the relationship between tea consumption and colon cancer risk in the US population.Design:Data from the NHANES I Epidemiologic Follow-up study (NHEFS) were used to examine the hypothesis. Cox proportional hazard models were used to examine the hypothesis of a protective effect of frequent tea consumption on colon cancer occurrence.Setting:Due to differences in the precision of the exposure data, we analysed two cohort periods based on the NHEFS. Cohort I was based on the survey conducted at the NHEFS baseline and Cohort II began at the first follow-up.Subjects:After excluding non-incidence cases and cases lost to follow-ups, there were 2359 tea users and 6498 non-tea users at baseline and 7656 tea users and 4514 non-tea users at the first follow-up.Results:After adjusting for confounders, the relative risks of colon cancer are 0.57 (95% confidence interval (CI) 0.42, 0.78) and 0.59 (95% CI = 0.35, 1.00) for subjects who consumed ≤1.5 cups and ≥1.5 cups per day, respectively, compared with non-tea users in Cohort II. Although more women consumed tea and the mean intake was higher, the preventive effect of tea consumption on colon cancer was found predominantly in men. The relative risks of colon cancer are 0.41 (95% CI = 0.25, 0.66) for men who consumed ≤1.5 cups day-1 and 0.30 (95% CI = 0.09, 0.98) for >1.5 cups day-1 of tea consumption (P-value for trend <0.01). No significant results were found in Cohort I.Conclusions:This study suggests an inverse association between colon cancer risk and habitual tea consumption.
Full-wave computation of constitutive parameters for lossless composite chiral materials

Composite chiral materials are realized by embedding large numbers of handed inclusions within a host material. A computational methodology is presented whereby the effective constitutive parameters of artificial chiral materials are computed while accounting for all self and mutual interactions among the inclusions. This technique combines a full-wave, Monte-Carlo scattering solution for randomly oriented inclusions together with an analytical solution for the scattering by a canonically-shaped body having a properly chosen constitutive model. It is believed that the effective constitutive parameters shown in this paper are the first full-wave computation of these quantities to appear in the literature. >
Markov Chain Analysis of Thermally Induced Soft Errors in Subthreshold Nanoscale CMOS Circuits

The development of future nanoscale CMOS circuits, characterized by lower supply voltages and smaller dimensions, raises the question of logic stability of such devices with respect to electrical noise. This paper presents a theoretical framework that can be used to investigate the thermal noise probability distributions for equilibrium and nonequilibrium logic states of CMOS flip-flops operated at subthreshold voltages. Representing the investigated system as a 2-D queue, a symbolic solution is proposed for the moments of the probability density function for large queues where Monte Carlo and eigenvector methods cannot be used. The theoretical results are used to calculate the mean time to failure of flip-flops built in a current 45-nm silicon-on-insulator technology modeled in the subthreshold regime including parasitics. As a predictive tool, the framework is used to investigate the reliability of flip-flops built in a future technology described in the International Technology Roadmap for Semiconductors. Monte Carlo simulations and explicit symbolic calculations are used to validate the theoretical model and its predictions.
Transportation Tax Ballot Initiatives as Regional Planning Processes

Local option taxes increasingly dominate transportation planning and finance in many states. In bypassing the formal metropolitan planning process, these taxes appear to put important regional policy goals at risk. The extent to which key policy issues (e.g., the equity, environmental, and regional transportation impacts of projects) were considered within the planning processes is examined, by drawing from archival research and interviews, for four of these tax measures at a critical stage, when they were becoming dominant in California. How these processes exhibit characteristics associated with "the new regionalism"—consensus building, pro-active visioning around untraditional policy goals, informal governance, and network-like organizational approaches—also is described.
Are We Ready to Try to Cure Alkaptonuria

It is very gratifying to see that alkaptonuria has now finally caught up with most of the other metabolic disorders formerly called “inborn errors of metabolism.” Thanks to these recent advances we have a much better understanding of the molecular basis and mutational events that produce this well-known prototypic metabolic disorder. Alkaptonuria is characterized by the passing of urine that blackens with the addition of alkali, by a gradual development of an intensive connective-tissue melanin-like pigmentation (ochronosis), and, with advancing years, by a type of arthritis that resembles osteoarthritis in its distribution but that also includes acute inflammatory episodes (La Du 1995).
Intrinsic dynamics in neuronal networks. I. Theory.

Many networks in the mammalian nervous system remain active in the absence of stimuli. This activity falls into two main patterns: steady firing at low rates and rhythmic bursting. How are these fi...