cssi/SciSciGPT-SciSciNet huggingface dataset:
The 21 Centimeter Forest

We examine the prospects for studying the pre-reionization intergalactic medium (IGM) through the so-called 21 cm forest in spectra of bright high-redshift radio sources. We first compute the evolution of the mean optical depth for models that include X-ray heating of the IGM gas, Wouthuysen-Field coupling, and reionization. Under most circumstances, the spin temperature T_S grows large well before reionization begins in earnest. As a result, the optical depth is less than 0.001 throughout most of reionization, and background sources must sit well beyond the reionization surface in order to experience measurable absorption. HII regions produce relatively large "transmission gaps" and may therefore still be observable during the early stages of reionization. Absorption from sheets and filaments in the cosmic web fades once T_S becomes large and should be rare during reionization. Minihalos can produce strong (albeit narrow) absorption features. Measuring their abundance would yield useful limits on the strength of feedback processes in the IGM as well as their effect on reionization.
Production of unsaturated uronides by bacterial hyaluronidases.

PNEUMOCOCCAL hyaluronidase has been shown to hydrolyse only the glucosaminidic bonds of hyaluronate1. The pneumococcal enzyme and other bacterial hyaluronidases have further been shown to differ from hyaluronidases of animal origin in their thermal lability, and in their capacity to hydrolyse hyaluronate faster and more completely. The main product of exhaustive hydrolysis of hyaluronate by testicular hyaluronidase is a tetrasaccharide2, whereas the end-product of the action of pneumococcal hyaluronidase is a fraction having the reducing values of a disaccharide1.
Artificial Neural Networks

This chapter contains sections titled: Model of an Artificial Neuron Architectures of ANNs Learning Process Learning Tasks Using ANNs Multilayer Perceptrons (MLPs) Competitive Networks and Competitive Learning SOMs Review Questions and Problems References for Further Study ]]>
Improving decision-making on the basis of experience

Publisher Summary This chapter discusses the improvement of decision making on the basis of experience. Decision making in general is subject to a trade-off between the sophistication of the procedure employed to make the decision, and the time and effort required to perform the analysis. Whether a more sophisticated procedure is worth using depends on whether the gain from its superior performance outweighs the extra cost. The key point about such trade-offs in the sophistication of the decision-making process is that, like the decisions themselves, they are highly dependent upon the particular planning environment. In the absence of a theory of the utility of decision-making sophistication as a function of the planning domain, the appropriate level of sophistication for a given domain must be determined empirically. The ability of a planner, in a decision making process, to adapt its decision-making to a domain depends in part upon its ability to optimize the trade-off between the sophistication of its decision procedures and their cost. As it is difficult to optimize this trade-off on a priori grounds alone, a planner should start with a relatively simple set of decision procedures and add complexity in response to experience gained in the application of its decision-making to real-world problems.
Potential Lifestyles in Ancient Environments of Gusev Crater, Mars

Habitable environments must sustain liquid water at least intermittently and also provide both chemical building blocks and useful sources of energy for life. Observations by Spirit rover indicate that conditions have probably been too dry to sustain life, at least since the emplacement of the extensive basalts that underlie the plains around the Columbia Memorial Station landing site. Local evidence of relatively minor aqueous alteration probably occurred under conditions where the activity of water was too low to sustain biological processes as we know them. In contrast, multiple bedrock units in West Spur and Husband Hill in the Columbia Wills have been extensively altered, probably by aqueous processes. The Fe in several of these units has been extensively oxidized, indicating that, in principle, any microbiota present during the aqueous alteration of these rocks could have obtained energy from Fe oxidation. Spirit discovered oliving-rich ultramafic rocks during her descent from Husband Hill southward into Inner Basin. Alteration of similar ultramafic rocks on Earth can yield H2 that can provide both energy and reducing power for microorganisms. Spirit s discovery of "salty" soil horizons rich in Fe and/or Mg is consistent with the aqueous dissolution and/or alteration of olivine. Such processes can oxidize Fe and also yield H2 under appropriate conditions. Very high S concentrations in these salty deposits indicate that soluble salts were mobilized by water and/or that S oxidation, a potential energy source for life, occurred. The Athena team has not yet established whether these salt components were deposited as large beds in ancient water bodies or, for example, were concentrated by more recent groundwater activity. Collectively these observations are consistent with the possibility that habitable environments existed at least intermittently in the distant geologic past.
Scientific Understanding and the Control of Nature

Modern science, for the most part, constrains the kind of theories that it entertains, and selects the kind of empirical data with which theories are related, to accord with “materialist strategies”. These strategies are adopted, I maintain, not because the objective of gaining understanding that manifests cognitive values highly always requires it, but because of an “elective affinity” (the elements of which I detail) between the materialist strategies and a certain outlook on the control of nature. A social value, thus, serves to ground the adoption of the materialist strategies. This, however, does not undermine the view that sound theory acceptance is based on “impartial” considerations, provided that the role of social values is kept properly distinct from that of cognitive values.
Detection of gene fusions in acute leukemia using bead microarrays.

This unit describes a method for the rapid and simultaneous detection of hybrid mRNAs (hRNA; also known as gene fusions, RNA fusions, or chimeric RNA), resulting from recurrent chromosome translocations or inversions in acute leukemia. The principal components of the assay are a multiplex RT-PCR, which simultaneously amplifies any of a number of possible hRNA targets, and a liquid bead microarray (LBMA), which is capable of unambiguously identifying the amplified hRNA. The entire procedure from RNA extraction to display of results can be broken into four steps: (1) conjugated-microsphere and LBMA manufacture and quality control, (2) cDNA synthesis, (3) multiplex PCR, and (4) hybridization of multiplex PCR products to the hRNA-detecting LBMA and assay read-out on a flow cytometer. The assay is designed to detect the most common risk-stratifying translocation in pediatric acute lymphoblastic leukemia, satisfying the demand for inclusion of genetic data in the diagnosis of acute leukemia as predicated by the current WHO classification of hematopoietic and lymphoid neoplasms. Keywords: hybrid mRNA; gene fusions; bead microarray; leukemia
The Boon and Bane of Radiocarbon Dating

Radiocarbon is widely used to determine the age of samples that are less than 50000 years old, but the conversion of radiocarbon ages to calendar ages is not always straightforward. In their Perspective, [ Guilderson et al ][1]. analyze the calibrated age ranges that can be obtained from the current calibration standard, the IntCall98 curve. They take into account not only the inherent limitations of the radiocarbon-calendar calibration curve, but also analytical uncertainties. The results bear directly on our ability to understand the dynamic climate system and the relations between climate and past societies. [1]: http://www.sciencemag.org/cgi/content/full/307/5708/362
Analytical analysis of STAP algorithms for cases with mismatched steering and clutter statistics

In the majority of adaptive radar detection algorithms, the covariance matrix for the clutter-plus-noise is estimated using samples taken from range cells surrounding the cell under test. In a nonhomogeneous environment, this can lead to a mismatch between the mean of the estimated covariance matrix and the true covariance matrix for the range cell under test. Further, an inaccurate target steering vector may also be employed. Closed form expressions are provided, which give the performance for such cases when any of a set of popular space-time adaptive processing (STAP) algorithms are used. The expressions are exact for some interesting cases. For some other cases, it is demonstrated that the expressions provide good approximations to the exact performance. To simplify the analysis, the samples from the surrounding range cells are assumed to be independent and identically distributed and these samples are assumed to be independent from the sample taken from the cell under test. A small number of important parameters describe which types of mismatches are important and which are not. Monte Carlo simulations are included which closely match the predictions of our equations. Numerical results demonstrate that steering vector mismatch can offset covariance matrix mismatch in some cases.
Cis-acting elements required for expression of the nonspecific cross- reacting antigen gene in colorectal carcinoma

Abstract BACKGROUND & AIMS: The nonspecific cross-reacting antigen (NCA) is a cell adhesion molecule, and the messenger RNA for NCA is overexpressed in 92% of colorectal carcinomas. The aim of this study was to determine the cis-acting elements that may be responsible for the expression of NCA. METHODS: Deletion mutants of the 5' flanking sequence and first intron were ligated into chloramphenicol acetyltransferase expression vectors, transfected into Chinese hamster ovary (CHO), DiFi, and HT-29 human colorectal carcinoma cells, and BxPC-3 and MDAPanc-28 human pancreatic carcinoma cells. The amount of acetylated chloramphenicol was determined to show the presence and activity of cis-acting sequences. RESULTS: The 5' flanking sequence functions as a promoter in all of cell lines and contains negative regulatory and enhancer sequences. The minimal promoter is active in Chinese hamster ovary and HT-29, though not in MDAPanc-28 cells. The first intron contains a silencer capable of suppressing a heterologous promoter. CONCLUSIONS: The results show cis-acting sequences within and 5' to the NCA gene, which appear to play a role in the expression of this gene in malignant tissues. Some of these sequences function in a cell type-specific manner. Further studies of these elements may provide insight into the mechanisms of the abnormal growth patterns of malignant cells. (Gastroenterology 1997 Mar;112(3):776-82)
Programmed instruction in communication education: An idea behind its time

This essay briefly reviews the basic assumptions upon which linear and branching programmed instruction methods are based, then speculates about why those methods did not catch on in communication education. The nature of the materials themselves; the timing of the development of programmed instruction methods; economic circumstances in the publishing industry; and faculty resistance which is based partly on fear and partly on ignorance, all guaranteed that programmed instruction, a good idea, could not have a future in communication education.
The SDSS-DR5 Survey for Proximate Damped Lyα Systems

Using the Sloan Digital Sky Survey Data Release 5 (SDSS-DR5), we survey proximate damped Ly? systems (PDLAs): absorption-line systems with H I column density NHI ? 2?1020 cm?2$N_{H ^{t{$ -->$t Igt Nt/Igt _{H ^{t{$ --> at velocity separation -->? v z ~ 5. However, the large ionizing flux emitted by a quasar can ionize the neutral gas in a nearby galaxy, possibly giving rise to a proximity effect, analogous to the similar effect observed in the Ly? forest. From a sample of 108 PDLAs, we measure the HI frequency distribution f(NHI, X)$f(N_{H ^{t{$ -->$t Igt ft/Igt (N_{H ^{t{$ -->, incidence, and gas mass density of the PDLAs near luminous quasars over the redshift interval -->z = 2.2?5. The incidence and mass density of PDLAs at -->z ~ 3 is approximately twice that of intervening DLAs, while at -->z 3.5 the f(NHI, X)$f(N_{H ^{t{$ -->$t Igt ft/Igt (N_{H ^{t{$ --> distribution is enhanced but statistically consistent with the intervening population. We interpret the observed enhancement of PDLAs around quasars in terms of quasar-galaxy clustering and compare the strength of the clustering signal to the expectation from independent measures of the respective clustering strengths of DLAs and quasars, as well as a complementary analysis of the clustering of absorbers around quasars in the transverse direction. We find that there are a factor of 5-10 fewer PDLAs around quasars than expected and interpret this result as evidence for the hypothesis that the ionizing flux from the quasars photoevaporates H I in nearby DLA galaxies, thus reducing their cross section for DLA absorption. This constitutes the first detection of a proximity effect for DLAs.
Thermal Transport Mechanisms in Carbon Nanotube-Nanofluids Identified From Molecular Dynamics Simulations

Atomistic simulations of carbon nanotubes (CNTs) in a liquid environment are performed to better understand thermal transport in CNT-based nanofluids. Thermal conductivity is studied using nonequilibrium molecular dynamics (MD) methods to understand the effective conductivity of a solvated CNT combined with a novel application of Hamilton‐Crosser (HC) theory to estimate the conductivity of a fluid suspension of CNTs. Simulation results show how the presence of the fluid affects the CNTs ability to transport heat by disrupting the low-frequency acoustic phonons of the CNT. A spatially dependent use of the Irving‐Kirkwood relations reveals the localized heat flux, illuminating the heat transfer pathways in the composite material. Model results can be consistently incorporated into HC theory by considering ensembles of CNTs and their surrounding fluid as being present in the liquid. The simulation-informed theory is shown to be consistent with existing experimental results. [DOI: 10.1115/1.4029913]
Six1 transcription factor is critical for coordination of epithelial, mesenchymal and vascular morphogenesis in the mammalian lung

Six1 is a member of the six-homeodomain family of transcription factors. Six1 is expressed in multiple embryonic cell types and plays important roles in proliferation, differentiation and survival of precursor cells of different organs, yet its function during lung development was hitherto unknown. Herein we show that Six1(-/-) lungs are severely hypoplastic with greatly reduced epithelial branching and increased mesenchymal cellularity. Six1 is expressed at the distal epithelial tips of branching tubules as well as in the surrounding distal mesenchyme. Six1(-/-) lung epithelial cells show increased expression of differentiation markers, but loss of progenitor cell markers. Six1 overexpression in MLE15 lung epithelial cells in vitro inhibited cell differentiation, but increases the expression of progenitor cell markers. In addition, Six1(-/-) embryos and newborn mice exhibit mesenchymal overproliferation, decreased Fgf10 expression and severe defects in the smooth muscle component of the bronchi and major pulmonary vessels. These defects lead to rupture of major vessels in mutant lungs after birth. Treatment of Six1(-/-) epithelial explants in culture with recombinant Fgf10 protein restores epithelial branching. As Shh expression is abnormally increased in Six1(-/-) lungs, we also treated mutant mesenchymal explants with recombinant Shh protein and found that these explants were competent to respond to Shh and continued to grow in culture. Furthermore, inhibition of Shh signaling with cyclopamine stimulated Six1(-/-) lungs to grow and branch in culture. This study provides the first evidence for the requirement of Six1 in coordinating Shh-Fgf10 signaling in embryonic lung to ensure proper levels of proliferation and differentiation along the proximodistal axis of epithelial, mesenchymal and endothelial cells. These findings uncover novel and essential functions for Six1 as a critical coordinator of Shh-Fgf10 signaling during embryonic lung development. We propose that Six1 is hence critical for coordination of proper lung epithelial, mesenchymal and vascular development.
Risk for Arrest: The Role of Social Bonds in Protecting Foster Youth Making the Transition to Adulthood

This study examines a sample of foster youth at the onset of the transition to adulthood and explores how social bonds are related to the risk of arrest during adulthood. Drawing from official arrest records, event history models are used to examine the time to arrest. Because individuals may be at risk for different types of crime, competing risk regression models are used to distinguish among arrests for drug-related, nonviolent, or violent crimes. Between the ages of 17–18 and 24, 46% of former foster youth experience an arrest. Arrests were evenly distributed across drug, nonviolent, and violent crimes columns. Although findings fail to support the significance of social bonds to interpersonal domains, bonds to employment and education are associated with a lower risk for arrest. Child welfare policy and practice implications for building connections and protections around foster youth are discussed.
Risk Factors for Asthmatic Patients Requiring Intubation. III. Observations in Young Adults

During recent decades, asthma prevalence and mortality have increased rapidly worldwide among children, teenagers, and young adults. Little attention has been placed on the latter group. Therefore, we studied risk factors for intubation in young adults as potential severity markers predictive of death. We analyzed demographic data from a retrospective cohort of hospitalized asthmatic young adults, including all asthmatics aged 20-34 years admitted over a 10-year period (1984-1994) to the University of California, Davis, Medical Center, Sacramento, California. A total of 550 such asthma admissions were reviewed, involving 351 women and 199 men, mean age 27.9 +/- 4.2 years. Of this group, 180 young adults were white, 209 were black, 118 were Hispanic, 16 were Asian, and 27 were American Indian. By National Heart, Lung, and Blood Institute guidelines, there were 95 mild, 322 moderate, and 133 severe cases. Thirty-four young adults required intubation for their asthma. Significant risk factors identified for intubation were psychological factors and psychosocial problems odds ratio (OR) 25.0; 95% confidence interval (Cl) 12.4, 50.8, prior intubation (OR 23.6; 95% Cl 7.5, 42.8), language barrier (OR 17.3, 95% Cl 7.9, 38.0), prior asthma emergency room visit in past year (OR 10.2; 95% Cl 4.6, 16.0), crowding (OR 8.5; 95% Cl 4.6, 16.0), prior asthma hospitalization in past year (OR 8.3; 95% Cl 3.3, 20.8), family dysfunction (OR 7.2; 95% Cl 3.6, 14.3), active smoking/secondhand smoke exposure (OR 7.1; 95% Cl 5.1, 9.9), respiratory infection (OR 6.0; 95% Cl 3.2, 11.5), low formal education (OR 5.7; 95% Cl 2.9, 11.2), unemployment (OR 4.9; 95% Cl 2.5, 9.5), steroid dependence (OR 4.6; 95% Cl 3.2, 6.4), and atopy (OR 4.3; 95% Cl 2.1, 8.5). These variables are important determinants of baseline risk factors.
Being immersed in social networking environment: Facebook groups, uses and gratifications, and social outcomes.

Abstract A Web survey of 1,715 college students was conducted to examine Facebook Groups users' gratifications and the relationship between users' gratifications and their political and civic participation offline. A factor analysis revealed four primary needs for participating in groups within Facebook: socializing, entertainment, self-status seeking, and information. These gratifications vary depending on user demographics such as gender, hometown, and year in school. The analysis of the relationship between users' needs and civic and political participation indicated that, as predicted, informational uses were more correlated to civic and political action than to recreational uses.
p21WAF1/CIP1 inhibits cell cycle progression but not G2/M-phase transition following methylmercury exposure

Abstract Methylmercury (MeHg) is an environmentally prevalent organometal that is particularly toxic to the developing central nervous system (CNS). Prenatal MeHg exposure is associated with reduced brain size and weight and a reduced number of neurons, which have been associated with impaired cell proliferation. We evaluate the role of p21, a cell cycle protein involved in the G 1 - and G 2 -phase checkpoint control, in the cell cycle inhibition induced by MeHg. Primary mouse embryonic fibroblasts (MEFs) of different p21 genotypes (wild-type, heterozygous, and null) were isolated at day 14 of gestation and treated at passages 4–6 with either 0, 2, 4, or 6 μM MeHg or 50 nM colchicine for 24 h. Changes in cell cycle distribution after continuous toxicant treatment were analyzed by DNA content-based flow cytometry using DAPI. MeHg induced an increase in the proportion of cells in G 2 /M at 2 and 4 μM MeHg ( p ≤ 0.05) irrespective of p21 genotype. Effects of MeHg on cell cycle progression were subsequently evaluated using BrdU–Hoechst flow cytometric analysis. Inhibition of cell cycle progression was observed in all p21 genotypes after continuous exposure to MeHg for 24 and 48 h. p21 null (−/−) cells reached the second-round G 1 at a higher fraction compared to the wild type (+/+) and heterozygous (+/−) cells ( p ≤ 0.05). These data support previous observations that MeHg inhibits cell cycle progression through delayed G 2 /M transition. Whereas the G 2 /M accumulation induced by MeHg was independent of p21 status, a greater proportion of p21(−/−) cells were able to complete one round of cell division in the presence of MeHg compared to p21(+/−) or p21(+/+) cells. These data suggest a role for p21 in retarding cell cycle progression, but not mitotic inhibition, following exposure to MeHg.
Scanning Tunneling Microscopy and Orbital-Mediated Tunneling Spectroscopy of N,N′-Dioctyl-1,8:4,5-naphthalenediimide Adsorbed on Highly Ordered Pyrolytic Graphite from Various Solvents and in Different Environments

Scanning tunneling microscopy (STM) and orbital-mediated tunneling spectroscopy (OMTS) are reported for N,N′-dioctyl-1,8:4,5-naphthalenediimide (diimide) adsorbed on highly ordered pyrolytic graphite (HOPG). The diimide forms well ordered monolayers either at the interface between HOPG and several phenylalkanes, or at the HOPG−air or HOPG−vacuum interface when adsorbed from toluene. Planar adsorption of the diimide ring on HOPG is observed. Hydrogen bonding, O and N interaction with HOPG, and π−π interactions appear to be the primary drivers for determining the monolayer structure which is stable and independent of the adsorption method. This is an unusual example since most alkane-substituted systems studied to date rely on alkane chain interactions (with HOPG and interdigitation) to drive the adsorbate structure on graphite. The observed unit cell has a = 2.0 ± 0.2 nm, b = 1.95 ± 0.2 nm, α = 67 ± 2°. The STM imaging is highly bias dependent and appears to be controlled (in the ±2 V bias region) by an un...
Anxiety and cerebral cortical metabolism in normal persons.

The State-Trait Anxiety Inventory (STAI) was administered to 43 normal volunteers immediately before and after a positron emission tomography (PET) procedure with [18F]-2-fluoro-2-deoxy-D-glucose (18F-FDG). High traitanxious individuals had significantly higher state (situational) anxiety associated with the PET scan procedure than did low trait-anxious persons. State anxiety decreased significantly for all respondents following the PET scan procedure. No significant relationships between global or regional cortical metabolic rates and state anxiety were observed. The direct cortical metabolic effects of heightened anxiety in the scan setting, should they exist, are likely obscured in the normal variance of the 18F-FDG method.
Thermal diffusivity of olivine-group minerals at high temperature

Thermal diffusivity ( D ) data from 12 oriented single crystals and seven polycrystalline samples of olivine group minerals were acquired with the laser-flash method at temperatures ( T ) of up to ~1500 °C. Samples included forsterite, Fe-Mg binary olivines, sinhalite, and chrysoberyl; specimens were characterized using infrared spectroscopy and electron microprobe analysis. Crystal orientation and chemistry both affect D . For our single crystals, D [100] > D [001] > D [010] at all temperatures. Thermal diffusivity decreases with increasing T and becomes virtually constant at high temperatures. At room temperature, D [001] of pure forsterite has the highest observed values, but substitution of a small amount of Co in forsterite (0.3 wt% CoO) lowers D by ~20%. Substitution of ~10% Fe for Mg in forsterite, as in typical mantle olivine, lowers D by ~50%. At room temperature, mantle olivine has D = 3.25, 1.66, and 2.59 mm2/s for the [100], [010], and [001] orientations, respectively. The values decrease to 0.93–0.87 mm2/s at 790–985 °C for [100], 0.54–51 mm2/s at 590–740 °C for [010] and 0.83–0.79 mm2/s at 740–890 °C for [001]. Two dunite samples have D of 0.55–0.56 mm2/s at 890–1080 °C, showing the effect of preferred orientation of grains dominated by [010]. Thermal diffusivity of polycrystalline samples is controlled by the large amounts of olivine present; minor phases offset the curves for D ( T ) from the value of the olivine mineral. Our laser-flash measurements isolate the phonon component of heat transfer from radiative transfer and show that the phonon contribution becomes nearly constant for the high temperatures expected in the mantle. The other microscopic component (diffusive radiative transfer) depends strongly on temperature and this temperature dependence likely exerts greater control on mantle convection.
Responsivity to NPY and melanocortins in obese OLETF rats lacking CCK-A receptors

Otsuka Long-Evans Tokushima Fatty (OLETF) rat lacking CCK-A receptors are hyperphagic and obese. Previous work has demonstrated alterations in neuropeptide Y (NPY) and proopiomelanocortin (POMC) mRNA expression in ad libitum fed OLETF rats compared to lean Long-Evans Tokushima Otsuka (LETO) controls. In order to determine whether alterations in sensitivity to central peptides involved in overall feeding control may contribute to the hyperphagia and obesity in OLETF rats, we assessed OLETF and LETO rats feeding responses to lateral ventricular infusions of NPY (1 and 3.2 nmol), the melanocortin 3/4 agonist MTII (0.1 and 0.32 nmol) and the melanocortin receptor antagonist SHU-9119 (0.25 and 0.5 nmol). At a 3-h time point, NPY increased food intake in both OLETF and LETO rats. OLETF rats were more sensitive, having significant increases at both NPY doses and a greater increase at the higher dose. The melanocortin agonist MTII decreased intake in both LETO and OLETF rats. At the 20-h time point, the magnitude of suppression was greater in OLETF rats. SHU-9119 increased food intake in both groups. OLETF rats were more sensitive with larger relative increase and longer-lasting effects at the lower dose. These results are consistent with demonstrated alterations in neuropeptide gene expression in OLETF rats and indicate that alterations in responsivity to NPY and melanocortin signaling are unlikely to contribute to their hyperphagia and obesity.
Guaranteed-quality Delaunay meshing in 3D (short version)

The main contribution of this paper is a new mesh generation technique for producing 3D tetrahedral meshes. Like many existing techniques, this one is based on the Delaunay triangulation (DT). Unlike existing techniques, thk is the first Delaunay-based method that is mathematically guaranteed to avoid slivers. A sliver is a tetrahedral mesh-element that is almost completely flat. For example, imagine the tetrahedron created as the (3D) convex hull of the four corners of a square; th~ tetrahedron has nicely shaped faces — all faces are 45 degree right-triangles — but the tetrahedron has zero volume. Slivers in the mesh generally lead to poor numerical accuracy in a finite element analysis. The Delaunay triangulation (DT) has been widely used for mesh generation. In 21), the DT maximizes the minimum angle for a given point set; thus, small angles are avoided. There is no analogous property involving angles in 3D. We make use of the Empty Circle Property for the DT of a set of point sites: the circumcircle of each triangle is empty of all other sites. In 3D, the analogous property holds: the circumsphere of each tetrahedron is empty of all other sites. The Empty Circle Property can be used as the definition of the DT. There is a vsst literature on mesh generation with most of the material emanating from the various applications communities. We refer the reader to the excellent survey by Bern and Eppstein [BE92]. We consider here only work related to the topic of mesh generation with mathematical quality guarantees. Chew [Che89] showed how to use the DT to triangulate any 2D region with smooth boundaries and no sharp corners to attain a mesh of uniform density in which all angles are greater than 30 degrees. An optimality theorem for meshes of nonuniform density was developed by Bern, Eppstein and Gilbert [BEG94] using a quadtree-based approach. Ruppert [Ru93] later showed that a modification of Chew’s algorithm could also attain the same strong results
Marking Time Along the Bulgarian-Turkish Border:

As a minority group, the Turks of Bulgaria faced a cruel paradox: in Bulgaria during 1984-1989, they were persecuted by the government because they were ‘Turkish’; in Turkey, the symbolic homeland to which they migrated en masse in 1989, they were marginalized by the local population on account of being ‘Bulgarian’. More than 300,000 Turks fled Bulgaria in 1989, and, although more than half of those immigrants have returned back to Bulgaria after the downfall of the Bulgarian communist government, economically induced migrations from Bulgaria to Turkey have continued apace in the 1990s. This article offers an ethnographic account of these transborder movements and their shifting meanings centered around three immigrants whose crossings have followed different paths: a post-1989 migrant looking for temporary work in Turkey who plans to return to Bulgaria in a couple of years; a 1989 immigrant who left Bulgaria because of the assimilation campaign and settled permanently in Turkey; and a migrant who was for...
The effect of newer tubercle bacillus digestion and decontamination procedures on fungi causing pulmonary diseases.

The paper concerns the effect of the newer tubercle bacillus digestion and decontamination procedures on the principal pulmonary mycotic disease agents in sputum The digestion-decontamination procedures used were: 1) N-acetyl-L-cysteine - sodium hydroxide, 2) dithiothreitol - sodium hydroxide, and 3) trisodium phosphate - Zephiran.
Analysis of the effects of lattice irregularity in photonic crystal fibers

Fabrication induced lattice imperfections in photonic crystal fibers are shown through numerical simulations to significantly change the coupling length of a two-core structure while confinement loss and dispersion of a typical fiber are more robust.
Magnetostrophic balance as the optimal state for turbulent magnetoconvection

The magnetic fields of Earth and other planets are generated by turbulent convection in the vast oceans of liquid metal within them. Although direct observation is not possible, this liquid metal circulation is thought to be dominated by the controlling influences of planetary rotation and magnetic fields through the Coriolis and Lorentz forces. Theory famously predicts that planetary dynamo systems naturally settle into the so-called magnetostrophic state, where the Coriolis and Lorentz forces partially cancel, and convection is optimally efficient. Although this magnetostrophic theory correctly predicts the strength of Earth's magnetic field, no laboratory experiments have reached the magnetostrophic regime in turbulent liquid metal convection. Furthermore, computational dynamo simulations have as yet failed to produce a magnetostrophic dynamo, which has led some to question the existence of the magnetostrophic state. Here, we present results from the first, to our knowledge, turbulent, magnetostrophic convection experiments using the liquid metal gallium. We find that turbulent convection in the magnetostrophic regime is, in fact, maximally efficient. The experimental results clarify these previously disparate results, suggesting that the dynamically optimal magnetostrophic state is the natural expression of turbulent planetary dynamo systems.
Dynamics of the photosynthesis of carbon compounds. I. Carboxylation reactions.

Abstract Kinetic studies have been made of the rates of appearance of 14 C in individual compounds formed by Chlorella pyrenoidosa during steady state photosynthesis with 14 CO 2 . These rates have been compared with rates of CO 2 and 14 C disappearance from the gas phase during the same experiments. 1. The following results were obtained: 2. 1. After the first few seconds, the rate of appearance of 14 C in compounds stable to drying on planchets at room temperature is 95 to 100% of the rate of uptake of carbon from the gas phase. 3. 2. After the first few seconds, the rate of appearance of carbon in compounds isolable by usual methods of paper chromatography constitutes at least 73 to 88% of the rate of uptake of carbon from the gas phase. Compounds formed from the carbon reduction cycle via the carboxylation of ribulose diphosphate account for a least 70 to 85% of the uptake, while carboxylation of phosphoenolpyruvic acid appears to account for at least another 3%. 4. 3. The induction period in the appearance of 14 C in stable compounds may be due to a reservoir of intracellular CO 2 and HCO 3 − or to some other volatile or unstable compound. If so, this reservoir contains no more than 1.5 μmoles of carbon, corresponding to about 7 sec carbon fixation in the experiment in which it was measured. 5. 4. No other carboxylation reactions, such as the carboxylation of γ-aminobutyric acid, could be observed. The rate of labeling of glutamic acid after 5 min of exposure of the algae to 14 CO 2 reached a maximum rate of about 5% of the total uptake rate, but this labeling appears to be due to conversion of labeled intermediates formed from the carbon reduction cycle or phosphoenolpyruvic acid carboxylation. 6. 5. The in vivo carboxylation of ribulose diphosphate in the light appears to be followed by conversion of the product to one molecule of phosphoglyceric acid, containing the newly incorporated 14 CO 2 and one molecule of some other (kinetically distinguishable) three carbon compound. This reaction would be different from the one reported for the isolated enzyme system and the in vivo reaction in the dark, which produces two molecules of 3-phosphoglyceric acid.
Effects of prenatal cocaine/crack and other drug exposure on electroencephalographic sleep studies at birth and one year

Objective. Little is known about the neurophysiologic effects of prenatal cocaine/crack use. The aim of this study, designed to overcome methodologic limitations of previous research, was to investigate the effects of prenatal cocaine use on electroencephalographic (EEG) sleep patterns, a marker of central nervous system development. Methods. In a longitudinal study of prenatal cocaine/crack exposure, women were interviewed at the end of each trimester about cocaine, crack, alcohol, tobacco, marijuana, and other drug use. Two-hour paper- and computer-generated EEG sleep recordings were obtained on a sample of the full-term infants on the second day of life and at 1 year postpartum. Eligible newborns were full-term, had received no general anesthesia, and had a 5-minute Apgar score >5. All infants whose mothers used one or more lines of cocaine during their first trimester or any crack ( n = 37) were selected. A comparison group was chosen randomly from the group of women who did not use cocaine or crack during their pregnancy ( n = 34). Results. Women who used cocaine/crack during the first trimester were older, less educated, less likely to be working, and used more tobacco, alcohol, marijuana, and other illicit drugs than women who did not use cocaine/crack during the first trimester. There were no differences in infant birth weight, length, head circumference, or gestational age between the two exposure groups. After controlling for the significant covariates, prenatal cocaine exposure was associated with less well developed spectral correlations between homologous brain regions at birth, and with lower spectral EEG power values at 1 year of age. Prenatal alcohol, marijuana, and tobacco use were found to affect state regulation and cortical activities. Conclusions. These results indicate that the neurotoxic effects of prenatal cocaine/crack use can be detected with quantitative EEG measures.
Evidence for the existence of a thermolabile element in adenovirus type 5 that plays a role during an early stage of infection.

Abstract In an attempt to learn the molecular mechanism behind the initial steps (before genome expression) of adenovirus infection, the effect of temperature treatment of adenovirus type 5 particles on their infectivity was studied. It was found that adenovirus type 5 could be inactivated by temperature treatment at between 43 and 44°C. Both biochemical and biophysical examination of adenovirus particles failed to disclose any significant changes after exposure to temperatures up to 45°C. Further, viral particles treated with the same temperature range retained their ability to attach to cell surface receptors and to penetrate the plasma membrane. Application of a temperature pulse of 44δC to adenovirus-infected HeLa cells indicates that the infection can be inhibited by exposure of infected cells to a brief temperature pulse of 44°C between 10 and 50 min postadsorption with a mid-point of 30 min postadsorption. In addition, electron microscopic examination of HeLa cells following a temperature pulse of 44°C suggests that there is a failure to accumulate viral particles at the perinuclear region. These findings support the hypothesis that adenovirus contains a thermolabile element which plays a crucial role during an early stage of infection. Possible correlation of this element with the adenovirus endogenous protein kinase is also examined and discussed.
A Pillared Three-Dimensional Manganese(II) Coordination Network Containing Rectangular Channels: Synthesis, X-Ray Structure, and Magnetic Properties

Abstract An unusual pillared 3-D manganese(II) coordination network based on carboxylate-bridged trimanganese cores [Mn6(isonicotinate)10(H2O)2](ClO4)2(EtOH)2(H2O)3, 1, was synthesized by treating manganese(II) perchlorate and 4-pyridinecarboxyaldehyde under hydro(solvo)thermal conditions. A single crystal X-ray diffraction study revealed that 1 contains rectangular channels that are occupied by perchlorate counterions and disordered ethanol and water guest molecules. The included ethanol and water guest molecules as well as the coordinated water molecules can be removed under vacuum at room temperature to afford a nanoporous solid that maintains the framework structure of 1. Magnetic measurements indicate antiferromagnetic interactions among the high-spin Mn(II) centers in 1 with coupling constants of −3.08 K and −4.96 K for the roughly isosceles triangular trimanganese cluster. Crystal data for 1: C64H62Cl2 Mn6N10O35, monoclinic space group P21/n, a=18.7892(3) A, b=23.2307(1) A, c=21.1355(4) A, B=95.085(1)°, Z=4, R1=0.0719, wR2=0.261, and GooF=1.02.
Cellular Arrhythmogenic Effects of Congenital and Acquired Long-QT Syndrome in the Heterogeneous Myocardium

Background —Certain alterations by mutations or drugs of the potassium currents I Ks and I Kr and the sodium current I Na give rise to several types of the long-QT syndrome. I Ks is heterogeneously distributed across the ventricular wall. Methods and Results —We investigated the effects of reducing I Ks or I Kr or enhancing late I Na (to simulate the 3 forms of long-QT syndrome) on action potential duration (APD) in the context of I Ks heterogeneity. We introduced I Ks heterogeneity in the Luo-Rudy dynamic cell model to simulate epicardial, endocardial, and midmyocardial (M) cells. Results demonstrated higher susceptibility of M cells to the development of arrhythmogenic early afterdepolarizations (EADs) in isolated cells and poorly coupled tissue. An important observation is that I Kr block or late I Na acts to increase APD differences between the cell types, whereas I Ks block minimizes such differences. Also, for normal transverse coupling, EADs develop in the endocardial region rather than in the M region as the result of strong electrotonic interaction. Conclusions — I Ks heterogeneity and intercellular coupling strongly influence EAD development during interventions or disorders that prolong APD. M cells in isolation or in poorly coupled tissue are more susceptible to EAD development than epicardial or endocardial cells. In well-coupled myocardium, EAD formation in the subendocardium can be the source of focal arrhythmias or provide the trigger for reentrant excitation. The efficacy of I Ks block in minimizing APD dispersion could have important implications for antiarrhythmic therapy.
Development of combinatorial chemistry methods for coatings: high-throughput screening of abrasion resistance of coatings libraries.

Design, validation, and implementation of an optical spectroscopic system for high-throughput analysis of combinatorially developed protective organic coatings are reported. Our approach replaces l...
Atomic Bethe-Goldstone Equations. I. The Be Atom

The nonrelativistic electronic energy of $\mathrm{Ne}(^{1}S)$ is computed by the variational solution of generalized Bethe-Goldstone (BG) equations. The sum of all two-particle net energy increments (pair correlation energies) is -0.3822 atomic units (a.u.), or 97.3% of the empirical correlation energy. The three- and four-particle net energy terms expected to be most important are computed and found to be smaller than 0.001 a.u. The computed pair correlation energies are analyzed in terms of symmetries induced in the BG equations, and are found to be represented well within the accuracy of the present calculations by the somewhat smaller number of parameters needed to characterize the $L$ and $S$ eigenstates of all possible eight-particle subsystems of the ten-electron Hartree-Fock reference state.
Diabetic nephropathy in African Americans

Diabetic nephropathy (DN) is the number one cause of end-stage renal disease in United States and is highly prevalent in African Americans. We have found that among African Americans in Mississippi diabetic nephropathy appears to affect females more than males, which may be related to increased rates of obesity and diabetes in African American women. Glycemic control and control of blood pressure is essential to prolong renal survival and to protect against cardiovascular events. Angiotensin-converting enzyme inhibitors reduce cardiovascular mortality in diabetics and are tolerated in advanced renal disease. The impact of glycemic control, appropriate antihypertensives, and the optimal level of blood pressure control in African Americans with advanced DN require further study. This article reviews the impact, clinical characteristics, risk factors, and treatment of diabetic nephropathy in African Americans.
Peroxisome proliferator‐activated receptor gamma agonists in the prevention and treatment of murine systemic lupus erythematosus

Peroxisome proliferator-activated receptor gamma (PPARγ) agonists are known to have many immunomodulatory effects. We have previously shown that the PPARγ agonist rosiglitazone is beneficial when used early in prevention of disease in murine models of systemic lupus erythematosus (SLE) and SLE-related atherosclerosis. In this report, we demonstrate that another PPARγ agonist, pioglitazone is also beneficial as a treatment for early murine lupus, indicating that this is a class effect and not agent-specific. We further attempt to define the ability of PPARγ agonists to ameliorate established or severe autoimmune disease using two mouse models: the MRL.lpr SLE model and the gld.apoE(-/-) model of accelerated atherosclerosis and SLE. We demonstrate that, in contrast to the marked amelioration of disease seen when PPARγ agonist treatment was started before disease onset, treatment with rosiglitazone after disease onset in MRL.lpr or gld.apoE(-/-) mice had minimal beneficial effect on the development of the autoimmune phenotype; however, rosiglitazone treatment remained highly effective at reducing lupus-associated atherosclerosis in gld.apoE(-/-) mice after disease onset or when mice were maintained on a high cholesterol Western diet. These results suggest that beneficial effects of PPARγ agonists on the development of autoimmunity might be limited to the early stages of disease, but that atherosclerosis, a major cause of death in SLE patients, may be ameliorated even in established or severe disease.
Restrictive pulmonary disease due to interlobular septal fibrosis associated with disseminated infection by Strongyloides stercoralis

Strongyloidiasis is caused by the nematode Strongyloides stercoralis. The parasite has a unique life cycle that enables it to cause a hyperinfection syndrome in which pulmonary involvement is characteristic. We describe the case of a 68-yr-old Hispanic male from Puerto Rico with disseminated strongyloidiasis who developed intense granulomatous reaction in the lung associated with interlobular septal fibrosis. Granulomatous lung disease leading to fibrosis within the lung has been well demonstrated in schistosomiasis, another parasitic disease. This case represents the first report, as far as we are aware, of fibrosis within the lung and restrictive pulmonary disease in association with Strongyloides stercoralis.
The Free Energies of Ligand-Binding to the Ionotropic Glutamate Receptor

Ionotropic glutamate receptors (iGluRs) are ligand-gated ion channels activated by glutamate. The binding of glutamate and other synthetic agonist molecules to the extracellular ligand-binding domains (LBDs) of these receptors drives the opening of cation-permeable transmembrane pores. Ligand-binding alters the conformational free energy landscape of LBD closure, which provides useful reversible work for opening the gate of the transmembrane ion channel. Using all-atom molecular dynamics simulations, we computed absolute LBD-ligand binding free energies for a set of different ligands to AMPA and NMDA receptor LBDs using a methodology formulated on the basis of potentials of mean force. The free energy of the full ligand-binding process is the sum of the free energy contributions from ligand-docking into an open LBD and LBD closure. Alterations in the free energy landscape of LBD closure are correlated with whether the bound ligand is a full agonist, partial agonist, or antagonist.
A novel switched interferometric quantum key distribution system

A novel system for ultra-long-distance quantum key distribution in optical fiber, incorporating ultra-low-noise transition-edge sensor (TES) photodetectors, is described. Integration of the TES detectors into the system was facilitated with a unique optically switched interferometer design. The performance of the system over 101 km of dark, single-mode fiber at 1550 nm and a clock rate of 1 MHz is described. Secret-key bits were produced after error correction and privacy amplification when using mean photon numbers of 0.01, 0.0148, 0.02, 0.0304, and 0.2 photons/pulse at the output of the transmitter. At a mean photon number of 0.1 photons per pulse at the transmitter, a transmission line loss of 29.92 dB, roughly equivalent to 150 km of optical fiber, could be tolerated and secret bits extracted from the transmitted key.