cssi/SciSciGPT-SciSciNet huggingface dataset:
Using eigenfunctions of the two‐point correlation function to study convection with multiple phase transformations

We describe and illustrate a new approach for extracting and understanding the pattern of flow in complex, time-dependent convection. In this approach we calculate the eigenfunctions of the two-point correlation function and show that the two-point correlation can be efficiently characterized by the dominant few eigenmodes. We apply this methodology to extract structural information from convection models with two phase transformations.
Laser speckle velocimeter utilizing optical fibers

Abstract A laser speckle velocimeter with a newly developed optical fiber probe is reported. An optical fiber with a graded-index rod lens at the end face is used for a laser beam guide and speckle velocity is detected by an optical fiber array spatial filter constructed with linearly arrayed end faces of optical fibers. By using optical fibers, a noncontact flexible and object distance independent velocimeter can be simply constructed.
A randomly perturbed iterative proper orthogonal decomposition (RI-POD) technique for filtering distributed parameter systems

In this paper, we consider the filtering of distributed parameter systems (DPS), i.e., systems governed by partial differential equations (PDE). We adopt a reduced order model (ROM) based strategy to solve the problem. We propose a randomly perturbed iterative version of the snapshot proper orthogonal decomposition (POD) technique, termed RI-POD, to construct ROMs for DPS that is capable of capturing their global behaviour. Further, the technique is entirely data based, and is applicable to forced as well as unforced systems. We apply the ROM generated using the RI-POD technique to construct reduced order Kalman filters to solve the DPS filtering problem. The methodology is tested on the 1-dimensional heat equation.
Sounds of silence: synonymous nucleotides as a key to biological regulation and complexity

Messenger RNA is a key component of an intricate regulatory network of its own. It accommodates numerous nucleotide signals that overlap protein coding sequences and are responsible for multiple levels of regulation and generation of biological complexity. A wealth of structural and regulatory information, which mRNA carries in addition to the encoded amino acid sequence, raises the question of how these signals and overlapping codes are delineated along non-synonymous and synonymous positions in protein coding regions, especially in eukaryotes. Silent or synonymous codon positions, which do not determine amino acid sequences of the encoded proteins, define mRNA secondary structure and stability and affect the rate of translation, folding and post-translational modifications of nascent polypeptides. The RNA level selection is acting on synonymous sites in both prokaryotes and eukaryotes and is more common than previously thought. Selection pressure on the coding gene regions follows three-nucleotide periodic pattern of nucleotide base-pairing in mRNA, which is imposed by the genetic code. Synonymous positions of the coding regions have a higher level of hybridization potential relative to non-synonymous positions, and are multifunctional in their regulatory and structural roles. Recent experimental evidence and analysis of mRNA structure and interspecies conservation suggest that there is an evolutionary tradeoff between selective pressure acting at the RNA and protein levels. Here we provide a comprehensive overview of the studies that define the role of silent positions in regulating RNA structure and processing that exert downstream effects on proteins and their functions.
Self-assembly of colloidal particles into three-dimensionally ordered arrays and its applications

This paper describes a convenient method for self-assembling monodisperse colloidal spheres into 3D ordered arrays with domain sizes as large as several square-centimeters. These arrays have a cubic-close-packed structure or a face-center- cubic lattice similar to that of a natural opal. Each array exhibits a stop band whose position is mainly determined by the diameter of the colloidal particles. This type of structure can serve as a 3D photonic band-gap crystal, which is potentially useful in controlling the emission and propagation of light. The versatility of the present technique has allowed us to tailor the photonic properties of these arrays of colloidal particles. For example, the maximum attenuation of the photonic band-gap can be modulated by controlling the number of layers along the propagation direction of the light. The position of the mid- gap can be roughly changed by controlling the diameter of the particles and subsequently fine-tuned by sintering the sample at elevated temperatures.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Spatially distributed modeling of surface water flow dynamics in the Everglades ridge and slough landscape

Summary A two-dimensional, spatially distributed flow dynamics model was developed and tested for a 1.5 by 4 km area of the patterned ridge and slough landscape of the Florida Everglades. This model is intended to support a deepened understanding of the system ecohydrological dynamics, and provide a useful tool for management decision support. The model was constructed with a fine enough mesh structure to ensure proper representation of ridge and slough topographic detail as well as capture local hydrologic influences. Upstream and downstream stage data collected near the study area in central Water Conservation Area 3A were used to establish the initial and boundary conditions. Water velocities measured in the ridges and sloughs over a 3-year period were used to calibrate and verify the model. Hydraulic resistance was computed using a power-law relationship with water depth. The simulated water levels, water depths, and flow velocities showed good agreement with the 3-year field-monitored data with percent model errors of approximately 4%, 12%, and 10%, respectively. Computed differences in hydraulic resistance between ridge and slough were reduced significantly during the storm season compared to the dry season. This suggests that more solute and suspended solid mass can be redistributed from the sloughs to the ridges in particular during wet seasons, due to the weakened heterogeneity of hydraulic resistance during high flows.
Fair value methodologies

Purpose – To describe the application of fair value methodologies to fund operations and emphasize the importance of appropriate valuation procedures.Design/methodology/approach – Discusses the need for appropriate valuation methodologies, describes a recent survey that shows how fair valuation policies and procedures have evolved over time, recommends procedures for adoption of consistent valuation procedures and industry practices, explains recent fund management trends such as the creation of separate valuation committees and the use of third‐party pricing vendors, and warns that valuation is becoming a more frequent subject of SEC examinations.Findings – Concludes that investment companies, private investment companies, boards, and managements are re‐evaluating and updating their valuation policies and procedures, partly in response to increased focus on valuations by the SEC in its examinations.Originality/value – Provides the results of a useful survey on fair value methodologies and important consi...
Tensilely strained germanium nanomembranes as infrared optical gain media.

The use of tensilely strained Ge nanomembranes as mid-infrared optical gain media is investigated. Biaxial tensile strain in Ge has the effect of lowering the direct energy bandgap relative to the fundamental indirect one, thereby increasing the internal quantum efficiency for light emission and allowing for the formation of population inversion, until at a strain of about 1.9% Ge is even converted into a direct-bandgap material. Gain calculations are presented showing that, already at strain levels of about 1.4% and above, Ge films can provide optical gain in the technologically important 2.1–2.5 μm spectral region, with transparency carrier densities that can be readily achieved under realistic pumping conditions. Mechanically stressed Ge nanomembranes capable of accommodating the required strain levels are developed and used to demonstrate strong strain-enhanced photoluminescence. A detailed analysis of the high-strain emission spectra also demonstrates that the nanomembranes can be pumped above transparency, and confirms the prediction that biaxial-strain levels in excess of only 1.4% are required to obtain significant population inversion.
Comparison of the nucleotide sequence of trpA and sequences immediately beyond the trp operon of Klebsiella aerogenes, Salmonella typhimurium and Escherichia coli

The nucleotide sequence of trpA of Klebsiella aerogenes is presented and compared with the trpA sequences of Salmonella typhimurium and Escherichia coli. The majority of the approximately 200 differences between each pair of trpA's are single nucleotide pair changes that do not alter the amino acid sequence. Codon usage conforms to the general patterns revealed by examination of other prokaryotic gene sequences. However, codon usage in K. aerogenes trpA reflects the high G+C content of the genome of this organism. The DNA sequences just beyond trpA, the presumed transcription termination region, are also compared for the three species. Perusal of these sequences indicates that the secondary structure of the transcript segment just beyond trpA has been preserved, while the primary sequence has diverged appreciably.
Effects of eddy initial conditions on nonlinear forcing of planetary scale waves by amplifying baroclinic eddies

The previous study of Young and Villere concerning growth of planetary scale waves forced by wave-wave interactions of amplifying intermediate scale baroclinic eddies is extended to investigate effects of different eddy initial conditions. A global, spectral, primitive equation model is used for the calculations. For every set of eddy initial conditions considered, growth rates of planetary modes are considerably greater than growth rates computed from linear instability theory for a fixed zonally independent basic state. However, values of growth rates ranged over a factor of 3 depending on the particular set of eddy initial conditions used. Nonlinear forcing of planetary modes via wave-wave coupling becomes more important than baroclinic growth on the basic state at small values of the intermediate-scale modal amplitudes. The relative importance of direct transfer of kinetic energy from intermediate scales of motion to a planetary mode, compared to baroclinic conversion of available potential energy to kinetic energy within that planetary mode, depends on the individual case. In all cases, however, the transfer of either kinetic or available potential energy to the planetary modes was accomplished principally by wave-wave transfer from intermediate scale eddies, rather than from the zonally averaged state. The zonal wavenumber 2 planetary mode was prominent in all solutions, even in those for which eddy initial conditions were such that a different planetary mode was selectively forced at the start. General characteristics of the structural evolution of the planetary wave components of total heat and momentum flux, and modal structures themselves, were relatively insensitive to variations in eddy initial conditions, even though quantitative details varied from case to case.
On bound states in the continuum of N-body systems and the virial theorem

Abstract We prove generalized versions of the quantum mechanical virial theorem and apply them to the investigation of the spectrum of N body Hamiltonians. We show, in particular, that for N particles interacting through 2-body potentials which may have singularities but “don't wiggle too much,” no positive energy bound state can exist. We also prove results on the absence of bound states with energy bigger than some value E 0 ⩾ − ∞ and extend them to the case of N particles interacting through ν-body forces ( ν = 1, 2,…, N ) and with an external electromagnetic field. Also some remarks for the case of a Dirac electron in an external potential are given as well as for some problems with boundary conditions. A by-product of this investigation is the unitarity of the S matrix and the strong asymptotic completeness for systems of N particles interacting by 2-body forces which are not restricted to be purely repulsive.
Mandible of Archaeopteryx provides an Example of Mosaic Evolution

THE upper Jurassic fossils Archaeopteryx lithographica and A. siemensii Dames offer the only direct evidence of the morphological transition between reptiles and birds. There is therefore a large literature about these fossils, which deBeer1 has summarized. Much attention has centred on the structure of the skull and its similarities and differences with those of reptiles and birds1–5. Unfortunately, the structure of the lower jaw has been entirely neglected, or casually dismissed, as reptilian rather than avian, principally because of the presence of thecodont teeth3. I have been able to study the morphological distinctions between the lower jaws of reptiles and birds, and the results have a direct bearing on the level of organization (morphological grade) of Archaeopteryx.
Theory of Lethal Mutagenesis for Viruses

Mutation is the basis of adaptation. Yet, most mutations are detrimental, and elevating mutation rates will impair a population's fitness in the short term. The latter realization has led to the concept of lethal mutagenesis for curing viral infections, and work with drugs such as ribavirin has supported this perspective. As yet, there is no formal theory of lethal mutagenesis, although reference is commonly made to Eigen's error catastrophe theory. Here, we propose a theory of lethal mutagenesis. With an obvious parallel to the epidemiological threshold for eradication of a disease, a sufficient condition for lethal mutagenesis is that each viral genotype produces, on average, less than one progeny virus that goes on to infect a new cell. The extinction threshold involves an evolutionary component based on the mutation rate, but it also includes an ecological component, so the threshold cannot be calculated from the mutation rate alone. The genetic evolution of a large population undergoing mutagenesis is independent of whether the population is declining or stable, so there is no runaway accumulation of mutations or genetic signature for lethal mutagenesis that distinguishes it from a level of mutagenesis under which the population is maintained. To detect lethal mutagenesis, accurate measurements of the genome-wide mutation rate and the number of progeny per infected cell that go on to infect new cells are needed. We discuss three methods for estimating the former. Estimating the latter is more challenging, but broad limits to this estimate may be feasible.
Resources, not Kinship, Determine Social Patterning in the Territorial Gunnison’s prairie Dog (Cynomys gunnisoni)

In this study, we describe patterns of relatedness in Gunnison’s prairie dog (Cynomys gunnisoni) social groups. Kin selection is often cited as a mechanism for the evolution and maintenance of social groups, and Gunnison’s prairie dog females are occasionally described as being strongly philopatric. Overall, randomization tests revealed that females within territorial groups were not more closely related to each other than expected at random. A similar pattern was found among males and between males and females, indicating that there was no sex-biased dispersal occurring in these populations. Ecological variables measured in this study, such as food abundance and food dispersion, were not correlated with relatedness. In addition, territory size and density ⁄m 2 did not correlate significantly with relatedness. Although there was variability in the spatial overlap among individuals within groups, there was no indication that relatedness explained this variation. These results suggest that kin selection is not maintaining social groups in these populations, but that competition for access to resources required by both males and females may explain dispersal and social group patterns in these populations.
Through the Looking Glass: Literacy, Writing Systems and Mirror-Image Discrimination

A part/whole judgment task was administered to adults in ten different language communities around the world. Participants were instructed to treat two-dimensional abstract line figures differently from the left/right mirror-image reflections of the same figures. The data support the proposal that sensitivity to this kind of mirror-image contrast is acquired: Literate individuals generally were better able to operate in terms of this distinction than were non-literate participants in the study. Contrary to this general pattern, however, Tamil literates as well as non-literates often treated the left/right mirror-image reflections as non-reflected figures, despite the training to treat them differently. The difference between the Tamil literates and the literate individuals in the other language communities sampled may reflect the fact that mirror-image contrasts are used to different degrees in their respective scripts.
Effect of surface morphology and temperature on the structural stability of nanoscale wavy films.

The atomic scale structural stability of freestanding wavy gold (Au) nanofilms was investigated using molecular dynamics simulations. The waviness in the Au film was formed by cleaving sinusoidal surfaces from a bulk crystal. The degree of waviness was varied by changing the wavelength of the sinusoidal surface profile. Films were then equilibrated at different temperatures (between 10 and 1080 K) and their structural stability was monitored. The MD simulation results revealed that the stability of films depends on temperature as well as the waviness of the film surface. It was shown that the size-dependent melting point depression of Au plays the dominant role in causing the structural instability of wavy films.
A strategy for exploiting the pseudosymmetry of the C1-C13 stretch of discodermolide.

The pseudo-C2 symmetry of the C1 to C13 stretch of the discodermolide structure offers a potential strategic advantage for synthetic design. Two approaches based on this recognition were devised, a...
Development and application of hybrid structure based method for efficient screening of ligands binding to G-protein coupled receptors.

G-protein coupled receptors (GPCRs) comprise a large superfamily of proteins that are targets for nearly 50% of drugs in clinical use today. In the past, the use of structure-based drug design strategies to develop better drug candidates has been severely hampered due to the absence of the receptor’s three-dimensional structure. However, with recent advances in molecular modeling techniques and better computing power, atomic level details of these receptors can be derived from computationally derived molecular models. Using information from these models coupled with experimental evidence, it has become feasible to build receptor pharmacophores. In this study, we demonstrate the use of the Hybrid Structure Based (HSB) method that can be used effectively to screen and identify prospective ligands that bind to GPCRs. Essentially; this multi-step method combines ligand-based methods for building enriched libraries of small molecules and structure-based methods for screening molecules against the GPCR target. The HSB method was validated to identify retinal and its analogues from a random dataset of ∼300,000 molecules. The results from this study showed that the 9 top-ranking molecules are indeed analogues of retinal. The method was also tested to identify analogues of dopamine binding to the dopamine D2 receptor. Six of the ten top-ranking molecules are known analogues of dopamine including a prodrug, while the other thirty-four molecules are currently being tested for their activity against all dopamine receptors. The results from both these test cases have proved that the HSB method provides a realistic solution to bridge the gap between the ever-increasing demand for new drugs to treat psychiatric disorders and the lack of efficient screening methods for GPCRs.
Vasodepressor effect of adenosine phosphates and 5'-adenylmethylene-diphosphonic acid, an analogue of adenosine triphosphate.

MEMBERS of the adenosine, adenosine monophosphate, adenosine diphosphate and adenosine triphosphate series produce a marked vasodepressor effect in the cat anaesthetized with nembutal. In this series, as the number of phosphate groups in the 5′ position is increased, the vasodepressor effect is also increased1.
Attribute based compiler implemented using visitor pattern

In our compiler course for undergraduate students, we use a class of attribute grammars to specify type information, target code, and other properties calculated for the source program. In the design of the compiler, a modification of the visitor design pattern allows us to transparently compute the attributes. Within our framework, implementation is straightforward; the emphasis of the course shifts to theory and specification. In several offerings of the course, students have implemented parts of a highly modular compiler for a small, statically typed object oriented language.
Clarifying the Relationship Between Education and Turnout

This study explores the influence of education on turnout. Although the basic relationship is well established, previous research has failed to investigate adequately the underlying causal mechanisms. In this study, four of the most prominent explanations are addressed: (a) education instills a sense of civic duty, (b) education increases sense of political efficacy, (c) education makes registration easier, and (d) education enhances political sophistication or awareness. Although each explanation has some merit, causal modeling reveals that education's positive influence on registration likelihood and political awareness is especially important in accounting for its relationship to turnout.
Intrinsic Fluorescence Excitation–Emission Matrix Spectral Features of Cottonseed Protein Fractions and the Effects of Denaturants

To better understand the functional and physicochemical properties of cottonseed protein, we investigated the intrinsic fluorescence excitation–emission matrix (EEM) spectral features of cottonseed protein isolate (CSPI) and sequentially extracted water (CSPw) and alkali (CSPa) protein fractions, and the effects of denaturants urea, guanidine hydrochloride, and sodium dodecyl sulfate. The EEM showed two contour peaks at the excitation wavelengths of 226 nm (Peak 1) and 277 nm (Peak 2). Addition of denaturants gradually shifted the emission maxima of both peaks from 335 nm to around 353 nm for CSPI and CSPa. The emission maximum (353 nm) of CSPw was unchanged by denaturation. These observations indicated that the tryptophan residues (fluorescence source) in the native CSPI and CSPa were protected within the micro hydrophobic environment, and gradually become water accessible with progressing denaturation. On the other hand, the tryptophan residues in native CSPw were already in contact with water. However, the fluorescence intensity of Peak 1 of all three protein samples decreased with increasing denaturant concentrations, suggesting similarity in some conformational changes in the three samples. Further exploration of the fluorescence mechanism of Peak 1 is needed to understand such similar conformational changes.
Biotin-labeled DNA probe in a PCR-based assay increases detection sensitivity for the equine hemoparasite Babesia caballi☆

A DNA probe from Babesia caballi (Bc1) was selected by antibody screening of a genomic library. The Bc1 probe hybridized specifically to B. caballi genomic DNA. A polymerase-chain-reaction-based assay for B. caballi DNA was developed from primers deduced from the probe nucleotide sequence. An amplified product of 1.6 kb was detected from as little as 500 fg B. caballi template DNA. Sensitivity increased 1000-fold when the biotin-labeled Bc1 probe was hybridized to the amplicons in a Southern blot.
A Laser-Induced Thermal Desorption/Fourier Transform Mass Spectrometry Study of Acetylene Cyclization on S/Pd(111): The Formation and Kinetics of Benzene, Thiophene, and 1,3-Butadiene

Acetylene cyclization on S/Pd(111) has been studied using laser-induced thermal desorption with Fourier transform mass spectrometry (LITD/FTMS). The formation of benzene, thiophene, and 1,3-butadiene has been observed on the surface at low temperatures. Investigations reveal that benzene and thiophene are formed in similar amounts and that the formation kinetics of each are comparable to one another. Results also show the kinetics of benzene formation on S/Pd(111) do not differ from that on a clean Pd(111) surface, indicating that the addition of S does not significantly alter the nature of the cylization process.
Modeling Braided Shields via multipole representations for the braid charges and currents

A first principles calculation for the transfer capacitance of a Beldon cable is carried out by the use of filamentary constant, dipole, quadrupole, and octopole unknown charges placed at the center of each braid wire. Results are compared with full electrostatic simulations and a phenomenological model.
Activation of P2-purinoceptors in the nucleus tractus solitarius mediate depressor responses

The purpose of the study was to examine the role of P2 purinergic receptors in mechanisms of cardiovascular control mediated by the nucleus tractus solitarius (NTS), a major integrative site in the brainstem involved in the reflex coordination of cardiorespiratory and visceral response patterns. Microinjections of ATP and its analogues were made into the subpostremal NTS of anesthetized, spontaneously breathing rats. ATP, alpha,beta-methylene ATP (alpha beta-meATP) and 2-methylthio-ATP (2-meSATP) produced significant dose-related reductions in arterial blood pressure. alpha beta-meATP was slightly more potent than ATP and 2-meSATP. Pretreatment with the P2 receptor antagonist, suramin (0.5 nmol/rat), into the same NTS site 10 min prior to agonist administration completely blocked pronounced depressor response pattern elicited by the highest dose of alpha beta-meATP (0.1 nmol/rat). The present findings suggest that endogenous ATP may serve as a fast transmitter substance in NTS-mediated mechanisms of cardiovascular control.
THE WOLF CREEK, WESTERN AUSTRALIA, METEORITE CRATER (CN =– 1278,192)*

This paper gives a brief preliminary report on an expedition to the Wolf Creek Crater, which recovered in excess of 1400 pounds of more-or-less completely oxidized meteoritic material, including 3 large, unusually dense, masses weighing 352, 336, and 324 pounds, respectively. Each of these big masses exceeds by nearly 100 times the largest specimens heretofore found at the Wolf Creek Crater. The smaller, less dense, specimens recovered appear to be much like the so-called “shale balls” found at the Barringer and Odessa Meteorite Craters. Photographs and descriptions of typical specimens and of the southwestern slope of the Wolf Creek Crater, on which the finds were made, are included in the paper.
Validation of depth-dependent fluorescence quenching in membranes by molecular dynamics simulation of tryptophan octyl ester in POPC bilayer.

Depth-dependent fluorescence quenching is an important tool for studying the penetration of proteins and peptides into lipid bilayers. Extracting quantitative information from quenching data is, however, complicated by (1) a limited number of experimentally available quenchers and (2) thermal disorder resulting in broad distributions of the transverse positions of both quenchers and fluorophores. Here we validate and refine a general approach to determining the location of a fluorescent probe along the bilayer normal from quenching data, based on a molecular dynamics (MD) simulation of a model compound, tryptophan octyl ester (TOE), in a 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) bilayer. The TOE ring was found to lie deeply within the bilayer (most probable position of 13.3 A and center-of-weight of the distribution of 14.8 A from the bilayer center), and it was very broadly distributed (with 9 A depth distribution width), which is consistent with previous experimental observations. The dept...
Is there room for punctuated equilibrium in macroevolution

The long-controversial theory of punctuated equilibrium (PE) asserts that speciation causes rapid evolution against a backdrop of stasis. PE is currently undergoing a resurgence driven by new developments in statistical methods. However, we argue that PE is actually a tangle of four unnecessarily conflated questions: (i) is evolution gradualistic or pulsed? (ii) does trait evolution occur mainly at speciation or within a lineage? (iii) are changes at speciation adaptive or neutral? and (iv) how important is species selection in shaping patterns of diversity? We discuss progress towards answering these four questions but argue that combining these conceptually distinct ideas under the single framework of PE is distracting and confusing, and more likely to hinder progress than to spur it.
Detection of nitric oxide and nitrogen dioxide with photoluminescent porous silicon.

The visible photoluminescence of porous Si is quenched by nitric oxide and nitrogen dioxide to detection limits of 1.4 × 10-3 and 5.3 × 10-5 Torr, respectively (corresponding to 2 ppm and 70 ppb). At analyte partial pressures in the low milliTorr range, the photoluminescence quenching is partially reversible; recovery from nitrogen oxide exposure occurs on a time scale of minutes. For both NO and NO2, the reversible photoluminescence quenching response fits a Stern−Volmer kinetic model. At higher partial pressures, quenching deviates from Stern−Volmer kinetics and some permanent loss of photoluminescence intensity occurs due to oxidation of the porous Si surface. Photoluminescence from porous Si is not quenched by nitrous oxide or carbon dioxide and only slightly quenched by carbon monoxide and oxygen.
Latin Language and Latin Culture: From Ancient to Modern Times

The Latin language is popularly imagined in a number of specific ways: as a masculine language, an imperial language, a classical language, a dead language. This book considers the sources of these metaphors and analyses their effect on how Latin literature is read. It argues that these metaphors have become idees fixes not only in the popular imagination but in the formation of Latin studies as a professional discipline. By reading with and more commonly against these metaphors, the book offers a different view of Latin as a language and as a vehicle for cultural practice. The argument ranges over a variety of texts in Latin and texts about Latin produced by many different sorts of writers from antiquity to the twentieth century.
In vivo measurement of glutamate loss is associated with synapse loss in a mouse model of tauopathy.

Abstract Glutamate is the primary excitatory neurotransmitter in the brain, and is implicated in neurodegenerative diseases such as Alzheimer's disease (AD) and several other tauopathies. The current method for measuring glutamate in vivo is proton magnetic resonance spectroscopy (1H MRS), although it has poor spatial resolution and weak sensitivity to glutamate changes. In this study, we sought to measure the effect of tau pathology on glutamate levels throughout the brain of a mouse model of tauopathy using a novel magnetic resonance imaging (MRI) technique. We employed glutamate chemical exchange saturation transfer (GluCEST) imaging, which has been previously validated as a complimentary method for measuring glutamate levels with several important advantages over conventional 1H MRS. We hypothesized that the regional changes in glutamate levels would correlate with histological measurements of pathology including pathological tau, synapse and neuron loss. Imaging and spectroscopy were carried out on tau transgenic mice with the P301S mutation (PS19, n = 9) and their wild-type littermates (WT, n = 8), followed by immunohistochemistry of their brain tissue. GluCEST imaging resolution allowed for sub-hippocampal analysis of glutamate. Glutamate was significantly decreased by 29% in the CA sub-region of the PS19 hippocampus, and by 15% in the thalamus, where synapse loss was also measured. Glutamate levels and synapse density remained high in the dentate gyrus sub-region of the hippocampus, where neurogenesis is known to occur. The further development of GluCEST imaging for preclinical applications will be valuable, as therapies are being tested in mouse models of tauopathy.
Acute effects of liposome aerosol inhalation on pulmonary function in healthy human volunteers.

Administering liposome-encapsulated drugs by aerosol is a feasible way of targeting drugs to the lungs. Prior to clinical application of aerosolized liposomes as drug carriers, their relative safety must be established. We evaluated the effects of inhaling nondrug-containing liposomes (15 and 150 mg of lipid per milliliter) for 1 h on pulmonary function and on oximetry in ten healthy nonsmoking volunteers. Spirometry was performed prior to and at intervals after inhalation, and subjects were monitored with pulse oximetry. Liposome inhalation was well tolerated, and no oxygen desaturation, decrements in pulmonary function, or side effects were noted. We conclude that inhalation of small particle aerosols of SPC liposomes produces no acute deleterious effects on pulmonary function in healthy subjects. (Chest 1991; 99:1268-70)
Potential Use of Biomarkers in Breast Cancer Risk Assessment and Chemoprevention Trials

: Several groups of investigators have explored the possibility that widespread morphologic and molecular changes in breast tissue of high-risk women may exist prior to breast cancer development and that these changes might be detected by random sampling. These tissue changes might serve as risk bio-markers if they are found to be associated with the development of cancer in prospective trials. We review here studies of morphologic and molecular abnormalities in nipple and fine needle aspirates in women at high risk for breast cancer. Cytologic evidence of hyperplasia with atypia detected by random sampling appears to have particular potential for development as a risk biomarker. If this morphologic change is found to be reversible with chemopreventive agents that are later found to prevent or delay the appearance of cancer, then hyperplasia with atypia as detected by random sampling may serve as a surrogate endpoint biomarker for response in phase II chemoprevention trials.
Speech processing in vocoder-centric cochlear implants

The principles of the most recent cochlear implant processors are similar to that of the channel vocoder, originally used for transmitting speech over telephone lines with much less bandwidth than that required for transmitting the unprocessed speech signal. An overview of the various vocoder-centric processing strategies proposed for cochlear implants since the late 1990s is provided including the strategies used in different commercially available implant processors. Special emphasis is placed on reviewing the strategies designed to enhance pitch information for potentially better music perception. The various noise suppression strategies proposed over the years based on multi-microphone and single-microphone inputs are also described.
Long-term effects of ionizing radiation on the rat spinal cord: intramedullary connective tissue formation

Light microscopy was used to evaluate the effects of ionizing radiation on spinal cords of rats irradiated when three days of age and killed at intervals up to 28 months after irradiation. The amounts of x-rays administered (2,000 R; 1,000 R; 500 R) were those which had been demonstrated by short-term studies to cause either no histopathologic changes or only transient, reparable alterations. The most significant and previously unreported finding was the development, usually restricted to the gray matter, of elongated, spindle-shaped cells that produce prodigious amounts of fibers clearly demonstrated by the Wilder's reticular stain. In cases where extensive cellular development had occurred, these cells were oriented around the perikarya of the large ventral motor neurons and formed a well-developed capsule of reticular fibers. This phenomenon occurred more frequently in rats receiving the greater amounts of radiation and killed 12 months or more after exposure. The other observation of interest was the development of lesser amounts of connective tissue-producing cells in the dorsal gray matter, where these cells were seen initially in the substantia gelatinosa. The significance of these changes is discussed in relation to previously reported long-term effects of ionizing radiation on the central nervous system. (auth)
Gaussianization of random inputs by filtering plants: The case of poisson white and telegraph processes

It is well known that low-pass filtering plants “harmonize” periodic inputs in the sense that the steady state response in close to harmonic. It has been observed, both experimentally and analytically, that low-pass filters “Gaussianize” some random inputs in the sense that the steady state response is close to being Gaussian. This Technical Note is intended to formalize the notion of Gaussianization and prove that it takes place for two types of input signals: Poisson white noise and telegraph processes. The general case is a subject of future work.
Flexible Mirror Imaging

The field of view of a traditional camera has a fixed shape. This severely restricts how scene elements can be composed into an image. We present a novel imaging system that uses a flexible mirror in conjunction with a camera to overcome this limitation. By deforming the mirror, our system can produce fields of view with a wide range of shapes and sizes. A captured image is typically a multi-perspective view of the scene with spatially varying resolution. As a result, scene objects appear distorted. To minimize these distortions, we have developed an efficient algorithm that maps a captured image to one with almost uniform resolution. To determine this mapping we need to know the shape of the mirror. For this, we have developed a simple calibration method that automatically estimates the mirror shape from its boundary, which is visible in the captured image. We present a number of examples that demonstrate that a flexible field of view imaging system can be used to compose scenes in ways that have not been possible before. This flexibility can be exploited in applications such as video surveillance and monitoring.
Attention-Deficit/Hyperactivity Disorder in School-Aged Children: Association With Maternal Mental Health and Use of Health Care Resources

Objective. To investigate the association between the mental health status of mothers and attention-deficit/hyperactivity disorder (ADHD) in their school-aged children and to characterize the health care access and utilization of families affected by ADHD. Methods. Survey logistic regression procedures were used to investigate the association between activity-limiting mental health conditions in mothers and ADHD in their school-aged children using 1998 National Health Interview Survey data. A total of 9529 mother-child dyads were included in the final analysis. Results. The prevalence of ADHD among children aged 4 to 17 years was 6.3%. Survey logistic regression statistics revealed an association between an activity-limiting depression, anxiety, or emotional problem in mothers and ADHD in their children. This association persisted after controlling for the gender, age, and race of the child; household income (as a function of the 1997 poverty level); and type of family structure as reported by the mother (adjusted odds ratio [OR]: 4.2; 95% confidence interval [CI]: 2.2–8.1). Mothers of a child with ADHD were 13 times more likely to have consulted with a mental health professional about their child’s health within the past year despite reporting an inability to afford prescription medications (OR: 3.3; 95% CI: 2.2–4.9) and mental health care (OR: 7.4; 95% CI: 4.6, 11.8) for the child. Conclusions. Maternal mental health is significantly associated with the presence of ADHD in school-aged children. This finding further supports a link between maternal mental health and behavioral outcomes in children. Health care utilization and access findings support a family-oriented system of care.
A power junction gate field-effect transistor structure with high blocking gain

A new gate structure is described for vertical-channel power junction gate field-effect transistors (FET's). This gate structure has vertically walled gate regions extending perpendicular to the wafer surface. The structure is fabricated by using orientation-dependent silicon etching and selective vapor-phase epitaxial refill techniques. In comparison to previous gate structures made by planar diffusion, the vertically walled gate structure exhibits one order of magnitude improvement in blocking gain. This improvement in blocking gain has allowed the fabrication of devices having breakdown voltages above 400 V and a current-handling capability of more than 0.5 A with an on-resistance of 12 Ω. The devices are designed to exhibit pentode-like characteristics at low gate voltages and triode-like characteristics at large reverse gate bias voltages in order to obtain the observed high-power handling capability.
Allopatric origins of microbial species.

Although allopatric divergence is a well-accepted mechanism of speciation for eukaryotic macro-organisms, the importance of geographical barriers to divergence in microbial populations is a subject of great debate. Do geographically separated populations of micro-organisms diverge independently, or does their structure fit the often quoted Bass-Becking description ‘everything is everywhere; the environment selects’? Aided by high-resolution genetic and genomic tools, the search for ‘microbial marsupials’ has revealed that in fact both are true; some species of micro-organisms demonstrate allopatric divergence, while others do not. This discovery opens the door for comparative analyses, where questions about the differences in evolutionary and ecological mechanisms that drive divergence and speciation in different microbial species can begin to be explored. Investigating these differences in evolutionary mechanisms will greatly enhance interest in, and understanding of, the dynamic processes that create and maintain the vast diversity of the microbial world.
Prediction of software reliability using feedforward and recurrent neural nets

The authors present an adaptive modeling approach based on connectionist networks and demonstrate how both feedforward and recurrent networks and various training regimes can be applied to predict software reliability. They make an empirical comparison between this new approach and five well-known software reliability growth prediction models using data sets from 14 different software projects. The results presented suggest that connectionist networks adapt well to different data sets and exhibit better overall long-term predictive accuracy than the analytic models. This observation is true not only for the aggregate data, but for each individual item of data as well. The connectionist approach offers a distinct advantage for software reliability modeling in that the model development is automatic if one uses a training algorithm such as the cascade correlation. Two important characteristics of connectionist models are easy construction of appropriate models and good adaptability towards different data sets (i.e., different software projects). >
Swimming: On Oxygen, Resistance, and Possibility for Immigrant Youth under Siege

In this article, we consider the ways in which educational policies and institutions today enable or obstruct young people who are immigrant English-language learners as they seek to cross cultural and educational borders. Contrasting a class action suit in California protesting high stakes testing that will significantly limit graduation rates, and an ethnographic analysis of the international high schools in which immigrant youth engage with cultural and educational depth and support and graduate at exceptional rates, this article challenges the current policy climate in which immigrant youth are increasingly under siege and at risk of being multiply undocumented. In the spirit of protest, we trace the many sites of resistance and possibility dotting the nation, in which educators, communities, families, advocates, and youth are demanding educational access and justice.
Observations on Myiasis by the Calliphorids, Bufolucilia silvarum and Bufolucilia elongata, in Wood Frogs, Rana sylvatica, From Southeastern Wisconsin

Larvae of certain species of blowflies (Calliphoridae) can cause myiasis in frogs and toads, but there are few reports from North American amphibians. Of these, most are from toads (bufonids). In this study, we observe primary myiasis in a population of juvenile wood frogs, Rana sylvatica, collected on 22-23 August 2003, from southeastern Wisconsin and compare our observations with previous studies on myiasis from toads. Two (5%) of 39 frogs were infected by the blow fly Bufolucilia silvarum, with an intensity of 28 and 31, whereas 1 (2.5%) of 39 frogs was infected by the blow fly Bufolucilia elongata with an intensity of 14. We found that (1) B. silvarum lay eggs on healthy wood frogs, (2) eggs hatch, with first-instar maggots penetrating under the skin, (3) maggots develop to mature third instars within 13-16 hr of egg hatching, (4) maggots kill the host within 7-47 hr of egg hatching, and (5) maggots consume the entire frog carcass reducing it to bones within 42-59 hr of egg hatching. Our observations on the time of death and how quickly carcasses of wood frogs were consumed by these maggots compared with previous studies on toads suggest that finding infected juvenile wood frogs may be uncommon. Therefore, myiasis by these flies on wood frogs and other small terrestrial anurans may be a phenomenon that is much more common than is currently observed. This is the first report of B. silvarum and B. elongata causing myiasis in wood frogs.
Efficient Fund of Hedge Funds Construction Under Downside Risk Measures

We consider portfolio allocation in which the underlying investment instruments are hedge funds. Benchmarks and conditional-value-at-risk motivate a family of utility functions involving the probability of outperforming a benchmark and expected shortfall from another benchmark. Non-normal return vectors with prescribed marginal distributions and correlation structure are modeled and simulated using the normal-to-anything method. A Monte Carlo procedure is used to obtain, and establish the quality of, a solution to the associated portfolio optimization model. Computational results are presented on a problem in which we construct a fund of 13 CSFB/Tremont hedge-fund indices.