cssi/SciSciGPT-SciSciNet huggingface dataset:
Second trimester serum predictors of preterm birth in a population-based sample of low-risk pregnancies

Objective To examine the relationship between typically collected second trimester maternal serum biomarkers and preterm birth among pregnancies without intrauterine-growth-retardation or other specific risk factors. Methods Included were 102 861 singleton pregnancies without specific risks that resulted in the live birth of an infant of normal birth weight for gestational age without aneuploidy or a neural tube defect. Logistic binomial regression analyses were used to estimate the relative risk (RR) of giving birth preterm among pregnancies with an abnormal level of alpha-fetoprotein (AFP), human chorionic gonatotropin (hCG), and/or unconjugated estriol (uE3) compared to pregnancies with normal biomarker levels. Results When compared to pregnancies with normal levels of AFP, hCG, and uE3, pregnancies with elevated levels of any biomarker [multiple of the median (MoM) ≥ 2.0] were at an increased risk for preterm birth regardless of preterm grouping (RRs 1.3–5.4). Risks for preterm birth tended to increase substantially when at least two biomarkers were elevated (RRs 2.2–18.7). Conclusion The results suggest that second trimester maternal serum biomarkers may help identify pregnancies at increased risk for preterm birth when no other identified risks are present. Data indicates that biomarkers may be particularly predictive of early preterm birth. Copyright © 2010 John Wiley & Sons, Ltd.
Thermodynamics of carbon coadsorbed with sulfur on Ni(100)

The thermodynamics of the segregation of dissolved carbon to a Ni(100) surface containing adsorbed sulfur has been studied by stimulated desorption using a low-current pulsed Ar+ beam at 2 keV, followed by laser ionization at 193 nm of the desorbed neutral species and reflecting time-of-flight mass spectrometry of the resulting C+ photo ions. Equilibrium surface-carbon coverages were measured for fractional sulfur coverages of 0, 0.1, 0.16, and 0.26 monolayer over a temperature range of 700 to 1100 K. Absolute carbon and sulfur coverages were calibrated by Auger electron spectroscopy of saturated, ordered overlayer structures. Identical carbon-segregation coverages obtained for both increasing and decreasing temperature profiles indicated that the measured carbon coverages represented equilibrium values. For fractional carbon coverages <0.15 monolayer with respect to the number of surface nickel atoms, the heat of formation of adsorbed carbon on Ni(100) was -28 ±7 kJ/mol; the Langmuir-McLean model was used to describe the segregation. the heat of formation of adsorbed carbon increases with increasing carbon coverage. Coadsorbed sulfur does not affect the heat of formation of adsorbed carbon for sulfur coverages ⩽0.16 monolayer. For a sulfur coverage of 0.26 monolayer, the heat of formation of adsorbed carbon increases to -7 ± 2 kJ/ mol. Coadsorbed sulfur reduces the maximum coverage of segregated carbon on Ni(100) from 0.5 with no coadsorbed sulfur to 0.24 for a sulfur coverage of 0.26 monolayer. The influence of coadsorbed sulfur on carbon during methanation on nickel is discussed.
The Disarticulation of Time: the Zeitbewußtsein in Phenomenology of Perception

In an effort to reassess the status of Phenomenology of Perception and its relation to The Visible and the Invisible, this essay argues that Merleau-Ponty's engagement with Husserl's text and his discussion of the “field of presence” in La temporalite are intended to think through the field in which time makes its appearance as one of passage. Time does not show itself as presence or in the present but manifests itself as Ablauf, as lapse or flow, an ecoulement that is simultaneously an explosion, an eclatement. Merleau-Ponty's account of temporality in these pages is thus legible as recovering the primordial experience of time as a self-differentiating dehiscence in its dual power of articulation and erosion. Time is thus simultaneously the vehicle of the world's appearance and of its “disarticulation”, the passage of a rhythm of affirmation and disintegration.
DAVID APPLE AND MILTON BONIUK, EDITORS Transscleral Choroidal Biopsy in the Diagnosis of Choroidal Lymphoma

A 57-year-old man with non-Hodgkin's B-cell lymphoma of the abdominal lymph nodes developed moderate cells in the anterior chamber and vitreous, choroidal infiltration, and total nonrhegmatogenous retinal detachment in both eyes while receiving chemotherapy. After a diagnostic vitrectomy in the left eye was nonrevealing, the patient was referred to the oncology service. Fine-needle aspiration biopsy of the choroidal infiltrate was not done because of poor visualization of the choroid through the turbid subretinal fluid. Transscleral choroidal biopsy was performed without complications and disclosed diffuse high-grade B-cell lymphoma and no signs of endogenous infection. Transscleral choroidal biopsy is a useful technique in eyes with choroidal infiltration, especially when hazy media prohibit fine needle biopsy.
Rural county can be efficient

Manager plan, tried for first time in sparsely populated area, cuts government costs to fit shrunken tax revenues after oil resources run out in Petroleurn County, Montana.
Soil: A Public Health Threat or Savior

Soil is the most complicated biomaterial on the planet due to complex soil architecture and billions of soil microbes with extreme biotic diversity. Soil is potentially a source of human pathogens, which can be defined as geo-indigenous, geo-transportable, or geo-treatable. Such pathogens cumulatively can and do result in multiple human fatalities annually. A striking example is Helminths, with current infections worldwide estimated to be around two billion. However, soil can also be a source of antibiotics and other natural products that enhance human health. Soilborne antibiotics are used to treat human infections, but can also result in antibiotic-resistant bacteria. Natural products isolated from soil resulted in 60% of new cancer drugs between the period 1983–1994. Soils are also crucial to human health through their impact on human nutrition. Finally, from a global perspective, soils are vital to the future well-being of nations through their impact on climate change and global warming. A critical r...
The effect of the quality of soil organic matter on sorption of naphthalene

A set of soil samples varying in age, diagenesis, and kind and amount of organic matter were examined to study the influence of effective polarity and aromaticity of soil organic matter (SOM) on naphthalene sorption using batch equilibration.Aromaticity of organic phases of the soils was calculated from CPMAS 13C NMR spectrum data and the soil effective polarity was calculated using the equation developed by Xing et al. [12]. Concentration of naphthalene in solution was measured using liquid scintillation counting. The quality of SOM markedly influenced sorption of naphthalene. Old SOM in shale showed higher affinity for naphthalene than that in the surface, young soils.Sorption of naphthalene increased with increasing aromaticity and decreasing polarity.The sorption coefficient (Koc) of organic contaminants cannot be accurately predicted from their Kow without some consideration of SOM quality such as polarity and degree of aromaticity.
CHARACTERIZATION, LOCALIZATION AND DISTRIBUTION OF alpha1 ADRENOCEPTOR SUBTYPE IN MALE RABBIT URETHRA

AbstractPurpose: The subtype specificity, localization and distribution of urethral alpha1-adrenoceptors were studied in the male rabbit urethra.Materials and Methods: The properties of the urethral alpha1-adrenoceptors were investigated using radioligand receptor binding and light microscopic autoradiography with [(125) I]iodo-2-[b-(4-hydroxyphenyl)-ethylaminomethyl]tetralone (HEAT), and immunohistochemistry with monoclonal anti-alpha smooth muscle actin and anti-alpha sarcomeric actin antibodies.Results: Saturation experiments with [(125) I]HEAT demonstrated the presence of significant amounts of a single high affinity binding site for alpha1 adrenoceptors in the male rabbit urethra. The pharmacological profile of the alpha1 adrenoceptors in rabbit urethra, determined by inhibition experiments with subtype selective alpha1 adrenoceptor antagonists, was characterized by the following rank order of potency of inhibition constants (Ki values): prazosin <or= to WB 4101 < spiperone < 5-methylurapidil < BMY 7...
Lead positioning strategies to enhance response to cardiac resynchronization therapy

Left ventricular lead position is one of the main determinants of CRT response. There are several approaches in LV lead positioning that include favoring an optimal anatomical position or targeting either the segment with maximal mechanical dyssynchrony or a region with maximal electrical delay. The conventional LV lead implantation faces several technical difficulties that may prevent the obtaining of a stable position and good performance of the LV lead without phrenic nerve stimulation. In addition, implant of the LV pacing lead in areas with myocardial scar may result in less than optimal cardiac resynchronization. Several strategies have been proposed to overcome all these obstacles including multimodality cardiac imaging to help in preprocedural or intraprocedural identification of the latest activated areas of the LV and the potential anatomical constraints. In selected patients, the surgical implant may be a solution to overcome these constraints. In the future, LV endocardial or epicardial multisite pacing may deliver an enhanced response to CRT.
Death on the Move: Landscape and Violence on the Highlands Highway, Papua New Guinea

A journey along the Highlands Highway from Mount Hagen in the center of the Highlands of Papua New Guinea to the port town of hoe on the northern coast provides an occasion for three streams of awareness: ethnographic locales associated with anthropological work; stories of past journeys, and their dangers, undertaken by our New Guinea companions; and an experience of present danger in the form of an armed holdup. The narrative holds these three streams together in counterpoint until the destination is reached, and the juxtaposition of themes mirrors the complexities of contemporary situations in Papua New Guinea, mingled with traces of anthropology's past.
Multidimensional Solitons in Irregular-Lattice Media

Localized nonlinear modes, i.e., solitons, are computed for the two-dimensional nonlinear Schrodinger equation with external lattices that posses vacancy defects, edge dislocations, quasicrystal and Bessel structures. Their stability properties are elucidated using direct numerical simulations.
Turnout and the Vote Revisited A Reply to Erikson

In his contribution to this volume, Erikson contends that the results of my previous research (Radcliff 1994) are an artifact arising from my failure to account for changes in electoral dynamics in...
A dynamic competition model for construction contractors

In construction, the issue of competition has been studied focusing on competitive bidding. The objective of most competitive bidding models is to find the optimum mark‐up to maximise the expected profit from a single firm's perspective. However, a firm's success depends on its long‐term interactions with the market and its competitors. To better understand competition in the market, there is a need to analyse competition from a dynamic market perspective. Building on previous models and relevant competition studies, a dynamic simulation model has been developed to provide an analytical framework for understanding dynamic competition. In this model, similar firms are equally exposed to demand uncertainties. Each applies its own policy, responding to market changes and to competitors' actions to optimise its market position. The firms' responses and their dynamic feedback are simulated and analysed. The results show how difficult it is for any firm to acquire a long‐term competitive advantage by means of b...
Psychotic symptoms in Alzheimer disease: evidence for subtypes.

Objective Psychotic symptoms in Alzheimer disease (AD) identify a phenotype with distinct neurobiology and genetic architecture. The authors investigated whether AD with psychosis is homogeneous or is a composite of subtypes. Methods Authors performed factor and cluster analyses of the psychotic-symptom items of the CERAD Behavioral Rating Scale in 188 probable and possible AD subjects who have displayed at least one psychotic symptom. Results Exploratory factor analysis resulted in a one-factor solution that comprised misidentification delusions, auditory and visual hallucinations, and the misidentification of people. Persecutory delusions were also frequently present and were independent of the misidentification/hallucination factor. Cluster analysis yielded similar results. Conclusion Misidentification/hallucinations and persecutory delusions may identify two subtypes of psychosis in AD. Longitudinal study is needed to determine whether these proposed subtypes remain stable and independent over time or merge into a single group over the course of illness.
Mitomycin and Fluorouracil With Concurrent Radiation (FUMIR) Regimen for Anal Cancer

Regimen name: FUMIR Origin of name: The regimen is named for the 2 drugs in the regimen, fluorouracil and mitomycin, with concurrent radiation.
A model for determining machine requirements in a multistage manufacturing system with discretely distributed demand

Abstract A model is presented for resolving the problem of determining the optimum number of machines, and their discrete operating rates, required to meet discretely distributed production demands with a minimum total expected cost. The model is developed for a serial, multistage manufacturing system with both straight-time and overtime operating periods.
Changes occurring in protein body structure and α-zein during cornflake processing

ABSTRACT Zeins, which comprise the majority of proteins in corn, are located in spherical organelles called protein bodies. Changes in protein body shape and release of encapsulated α-zeins as a result of cornflake processing (conventional pressed or extrusion flaking) were investigated. Size-exclusion chromatography, SDS-PAGE, and protein solubility tests showed that, upon cooking, zein proteins form large, disulfide-bound polymers, many of which were insoluble in nonreducing solvents. Transmission electron microscopy with immunogold staining revealed that cooking had no effect on protein body structure in corn, but after processing to cornflakes, protein body structure was altered. In conventional pressed cornflakes, the protein bodies were flattened, partially fused together, and α-zeins were to some degree released, whereas in the extruded flakes, protein bodies were completely disrupted and α-zeins dispersed. These results suggest that zeins in cornflakes, particularly extruded ones, are not confined...
Identification of Pore-forming Subunit of P-type Calcium Channels: an Antisense Study on Rat Cerebellar Purkinje Cells in Culture

Treatment of cerebellar neurones in culture with an antisense oligonucleotide (ODN) against α1A, reduced the whole-cell P-type calcium channel current relative to mismatch ODN treated controls (p < 0.001). Therefore, AgaIVA (50 nM) reduced whole-cell calcium current in mismatch and antisense treated cells by 70 ± 4 and 19 ± 3%, respectively. © 1997 Elsevier Science Ltd. All rights reserved.
From Theory to Data: The Process of Refining Learning Progressions

Learning progressions (LPs) are theoretical models of how learners develop expertise in a domain over extended periods of time. Recent policy reports have touted LPs as a promising approach to aligning standards, curriculum, and assessment. However, the scholarship on LPs is relatively sparse, and the jury is still out on the theoretical and practical value of this approach. To realize any potential of LPs researchers need to systematically refine these hypothetical models in real-world contexts. Such refinement efforts are challenging, as they require the coordination of messy empirical data with often underspecified theoretical models. Many of the current reports involving the empirical refinement and validation of LPs do not sufficiently explicate the process of how one goes about making modifications to the LP based on empirical data. In this article we present heuristics for facilitating the coordination of data and LP models. Using an illustrative example of a genetics LP and data from a 2-year long...
NMR metabolomics of planktonic and biofilm modes of growth in Pseudomonas aeruginosa

Bacteria often reside in communities where the cells have secreted sticky, polymeric compounds that allow them to attach to surfaces. This sessile lifestyle, referred to as a biofilm, affords the cells within these communities a tolerance of antibiotics and antimicrobial treatments. Biofilms of the bacterium Pseudomonas aeruginosa have been implicated in cystic fibrosis and are capable of colonizing medical implant devices, such as heart valves and catheters, where treatment of the infection often requires the removal of the infected device. This mode of growth is in stark contrast to planktonic, free floating cells, which are more easily eradicated with antibiotics. The mechanisms contributing to a biofilm's tenacity and a planktonic cell's susceptibility are just beginning to be explored. In this study, we have used a metabolomic approach employing nuclear magnetic resonance (NMR) techniques to study the metabolic distinctions between these two modes of growth in P. aeruginosa. One-dimensional 1H NMR sp...
MEF2B Is a Component of a Smooth Muscle-specific Complex That Binds an A/T-rich Element Important for Smooth Muscle Myosin Heavy Chain Gene Expression

To understand smooth muscle-specific gene expression, we have focused our studies on the smooth muscle myosin heavy chain (SMHC) gene, a smooth muscle-specific marker. In this study, we demonstrate that the SMHC promoter region (-1594 to -1462 base pairs) containing the A/T-rich element can activate the heterologous thymidine kinase promoter in smooth muscle cells, but not in fibroblasts. Mutations of this A/T-rich element decreased SMHC promoter activity significantly. Both gel mobility shift assays and DNase I footprinting revealed that this region binds to specific protein complexes from smooth muscle nuclear extracts, whereas nuclear extracts from skeletal muscle and fibroblasts produced a different binding pattern. We also demonstrate that the protein complex obtained from smooth muscle nuclear extract reacts with MEF2B-specific antibody, but not with antibodies specific to MEF2A, MEF2C, or MEF2D, suggesting that only MEF2B protein binds to the A/T-rich element. Furthermore, MEF2B overexpression in smooth muscle cells up-regulated the SMHC promoter, suggesting that MEF2B is important for SMHC gene regulation. This is the first report demonstrating a role for MEF2 factors in smooth muscle-specific gene expression.
Bank-Barrier Reef Morphogenesis, St. Croix, United States Virgin Islands: ABSTRACT

Bank barriers are the major structural reef type in the eastern Caribbean, yet their internal structure and formation process are poorly understood. Twenty-six core holes drilled along the northern St. Croix barrier and on a transect combined with a ship-channel section through the southern bank barrier have shown that this is a bar-type structure which consists of a series of patch reefs within a carbonate sand and rubble matrix capped by reef-crest and fore-reef facies. Locally, reef linearity and location are controlled by a 4-m limestone step of Pleistocene age. These bank reefs apparently were initiated by shelf-current deposition of carbonate traction load in a bar configuration. Scattered corals--Porites porites, Diploria spp., Acropora cervicornis, and dominantly Montastrea annularis--acted to stabilize the bank. Framework-dominated patch reefs developed at scattered locations and depths as the bank grew upward. As the reefs built into shallow water, carbonate production increased, eventually coalescing them into a continuous reef crest. Core return shows that the structure is characterized by little cementation. Cement occurs in localized lenses within the structure just as it does along the present reef surface. Framework construction is concentrated in patch-reef, reef-crest, and fore-reef facies. This type of construction produces highly permeable structures with extremely high local porosity. Extensively cemented caps occur only in areas having low accumulation rates and in areas of high energy. Bank-barrier reefs are probably also important in the Indo-Pacific in exposed non-atoll situations, but their occurrence is generally not recognized. Descriptions of Mesozoic and Cenozoic reefs suggest that the bank reef is an extremely important but little understood type in the fossil record also. End_of_Article - Last_Page 427------------
Some properties of propionyl CoA carboxylase partially purified from human liver

Abstract Some properties of propionyl CoA carboxylase partially purified from human liver are described. The human enzyme is biotin linked, has a pH optimum between 8.0–8.5 and is activated by the monovalent cations NH 4 + , K + , Cs + and Rb + . Li + , Na + and tetramethylammonium bromide do not produce activation. The enzyme preparation catalyses the carboxylation of butyryl and acetyl CoA at a rate of 5% and 2%, respectively, of that at which propionyl CoA is carboxylated. The apparent K m of activation for K + was 4.5 × 10 −3 m , and for NH 4 + was 5.5 × 10 −3 m . The pH optimum, biotin requirement and the activation by the above monovalent cations compare with the properties described for purified bovine liver and porcine heart propionyl CoA carboxylase.
Nonstationary Phase of the Plio-Pleistocene Asian Monsoon

Paleoclimate records indicate that the strength of the Asian summer monsoon is sensitive to orbital forcing at the obliquity and precession periods (41,000 and 23,000 years, respectively) and the extent of Northern Hemisphere glaciation. Over the past 2.6 million years, the timing (phase) of strong monsoons has changed by ∼83 degrees in the precession and ∼124 degrees in the obliquity bands relative to the phase of maximum global ice volume (inferred from the marine oxygen isotope record). These results suggest that one or both of these systems is nonstationary relative to orbital forcing.
Echo parameter estimation for ultrasonic NDE applications via a two-step compressed sensing

The recently developed compressed sensing (CS) framework has been applied to various data intensive imaging applications. It provides significant reductions in sampling rate with minimal loss in image quality. In this investigation, a CS-based sampling scheme is introduced for ultrasonic nondestructive evaluation (NDE) signals. The feasibility of parameter estimation based on the new sampling method is explored. Especially, a two-step compressed sensing with Gaussian chirplet model is proposed for data acquisition and echo parameter estimation. The CS framework is utilized to estimate the time-of-arrivals (TOAs) of chirplets. With the estimated TOAs, another iteration of data acquisition is performed to acquire the echo amplitude accurately. It has been shown that the two-step CS can estimate the TOAs of ultrasonic echoes with high accuracy in the presence of noise with SNR as low as -5 dB. Furthermore, the estimation is robust to inaccurate knowledge of the transducer bandwidth.
Efficient Low-Cost Testing of Wireless OFDM Polar Transceiver Systems

Polar radio architectures are attractive due to the ability to implement them using largely digital architectures. However, testing for specs such as EVM incurs significant test time due to the large numbers of symbols that need to be transmitted. In our approach, EVM is modeled as a function of the system static non-idealities (IQ mismatch, gain, IIP3 parameters) and dynamic non-idealities (VCO phase noise). Using a multi-tone test stimulus, the static and dynamic non-idealities are estimated first. The data generated is used to predict EVM using machine learning methods with high accuracy while incurring minimal test time.
Robust real-time detection of multi-color markers on a cell phone

We describe a fast algorithm to detect special multi-color markers with a camera cell phone. These color markers can be used for environmental labeling, for example, as a wayfinding aid for persons with visual impairment. Using a cascade of elemental detectors, robust detection is achieved at an extremely low computational cost. We also introduce a strategy to select surfaces for the marker that ensure very low specular reflection, thus facilitating color-based recognition.
Computer graphics in music performance research

Theories of skilled music performance must account for variations on what is written in traditional musical notation. Some variations are intentional and reflect structural features of the music that are chosen for emphasis by the performer. Current music notations are inadequate to reflect these variations. Computer applications are described that allow graphical and statistical examination of performance variations on traditional musical notation. An integrated set of visual and sound tools is provided that allows music to be recorded, edited, analyzed, and played back on electronic and acoustic musical instruments. The graphical format allows flexibility through the use of windows, compression, expansion, and scrolling of multiple sources of information, mapping of acoustic to visual dimensions, and scaling of different performance parameters without normalization. Experimental evidence from piano performances is used to demonstrate how graphical formats can aid research on human performance.
Remodelling of the neuromuscular junction after subtotal disuse

Within 5 days after reduction of activity of the rat soleus muscle, there was remodelling of the neuromuscular junction. Post-synaptic clefts were shorter, wider, and flatter, whereas nerve terminals showed sprouting and longitudinal distortion. The results, which differ from those found after denervation or total disuse, reveal the plasticity of the mature neuromuscular synapse.
Stochastic dynamics of parametrically excited two D.O.F. systems with symmetry

In this paper we investigate the non-linear dynamics of a two-degree-of-freedom system with symmetries subject to random parametric excitation. The study of this non-linear near-Hamiltonian system is simplified by using the symmetry and separation of scales present in the problem. To this end, we study the equations as a random perturbation of a four-dimensional weakly dissipative Hamiltonian system. We achieve the model-reduction through stochastic averaging and the reduced process is simply a Markov process on a line. Examination of the reduced Markov process on the line yields many important results, namely, probability density functions, and stochastic bifurcations. The steady state dynamics is computed explicitly. Phenomenological and dynamical bifurcations are investigated. The approach adopted in this paper can in principle, be applied to any four-dimensional integrable system.
Dynamics of vertical-cavity surface-emitting semiconductor lasers with polarization-isotropic optical feedback

We study the dynamics of a vertical-cavity surface-emitting laser with polarization isotropic optical feedback using the San Miguel, Feng, and Moloney model, which considers the role of carrier spin dynamics in both the conduction and the valence bands. Two transitions coupled to right- and left- circularly polarized light are coupled by spin-flip processes, which are characterized by the spin relaxation rate, (gamma) s. With moderately strong optical feedback and close to the solitary laser threshold the laser dynamics depend significantly on the value of (gamma) s. For low spin relaxation rates the time-averaged intensity often shows abrupt dropouts, similar to those observed in edge- emitting semiconductor lasers. Underlying the dropouts there is antiphase competition between the time-averaged orthogonal linearly polarized components of the electric field. For large values of the spin relaxation rate the dropouts tend to disappear and the time-averaged intensity is constant or nearly constant, depending on the stability of the linearly polarized states of the laser without feedback.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Ammonia oxidation and ammonia-oxidizing bacteria and archaea from estuaries with differing histories of hypoxia

Nitrification, the oxidation of NH(4)(+) to NO(2)(-) and subsequently to NO(3)(-), plays a central role in the nitrogen cycle and is often a critical first step in nitrogen removal from estuarine and coastal environments. The first and rate-limiting step in nitrification is catalyzed by the enzyme ammonia monooxygenase (AmoA). We evaluate the relationships between the abundance of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) amoA genes; potential nitrification rates and environmental variables to identify factors influencing AOA abundance and nitrifier activity in estuarine sediments. Our results showed that potential nitrification rates increased as abundance of AOA amoA increased. In contrast, there was no relationship between potential nitrification rates and AOB amoA abundance. This suggests that AOA are significant in estuarine nitrogen cycling. Surprisingly, more of the variability in potential nitrification rates was predicted by salinity and pore water sulfide than by dissolved oxygen history.
PICOSECOND PROCESSES IN CHEMICAL SYSTEMS: VIBRATIONAL RELAXATION

Studies of picosecond processes have now been underway for one and one half decades. The level of detail exposed in experiments has roughly paralleled the advances in laser technology that have taken place during that period. The first applications of picosecond lasers to chemical problems used the solid state lasers neodymium-glass and ruby. The slow repetition rate and poor reproducibility of these systems allowed only rather coarse grain experiments. The attempts to measure statistical limit radiationless processes in azulene (1–3) and benzophenone (3–5), and studies of nearest neighbor energy transfer between (6) and within (7) molecules are but few of the processes that were studied with these early picosecond lasers. The important contributions of Kaiser and coworkers on vibrational relaxation in liquids (8,9) involved measurements of coherent Raman scattering and were made possible by more careful,control of the Nd: glass laser to generate transform limited TEMoo pulses. A subsequent development involved the picosecond generated continuum (10), which has allowed accurate absorption spectra to be recorded, even at low laser repetition rates, by incorporating extensive multiplexing capabilities (11).
Up-regulation of matrix in bovine articular cartilage explants by electric fields.

Abstract Electric stimulation has long been used as a tool to promote connective tissue healing, but the mechanism(s) by which this is accomplished are not yet known. We have previously determined, using mass cultures of fetal bovine articular chondrocytes, a specific set of capacitively coupled electrical stimulation parameters (e.g., duration of stimulation, response time, amplitude, frequency, and duty cycle) that significantly elevated production of collagen and proteoglycan, and up-regulated type II collagen and aggrecan mRNA expression in vitro. In the present study, we applied our best signal parameters (30-min continuous stimulation (100% duty cycle) followed by a pulsed (1 h on, 5 h off, 4×/day) 50% (1 min on, 1 min off) duty cycle) to cultures of adult bovine articular cartilage explants and obtained similar results. Since the latter system more closely mimics the in vivo chondrocyte environment, these data argue for the utility of electric stimulation for the maintenance of adult cartilage matrix in situ.
Carbon fiber reinforced concrete for smart structures capable of non-destructive flaw detection

Electrically conducting concrete, as provided by the addition of a short carbon fibers (0.2-0.4 vol.%) to concrete, can function as smart structure material that allows non-destructive electrical probing for the monitoring of flaws. The electrical signal is related to an increase in the concrete's volume resistivity during crack generation or propagation and a decrease in the resistivity during crack closure. The linearity between the volume resistivity change and the compressive stress was good for mortar containing carbon fibers together with either methylcellulose or latex as dispersants. However, the linearity was poor for mortar containing carbon fibers together with both methylcellulose and silica fume, as this mortar required a minimum compressive stress for crack closure, whereas the other two mortars did not.
Evaluation of magnetic resonance imaging issues for implantable microfabricated magnetic actuators

The mechanical robustness of microfabricated torsional magnetic actuators in withstanding the strong static fields (7 T) and time-varying field gradients (17 T/m) produced by an MR system was studied in this investigation. The static and dynamic mechanical characteristics of 30 devices were quantitatively measured before and after exposure to both strong uniform and non-uniform magnetic fields. The results showed no statistically significant change in both the static and dynamic mechanical performance, which mitigate concerns about the mechanical stability of these devices in association with MR systems under the conditions used for this assessment. The MR-induced heating was also measured in a 3-T/128-MHz MR system. The results showed a minimal increase (1.6 °C) in temperature due to the presence of the magnetic microactuator array. Finally, the size of the MR-image artifacts created by the magnetic microdevices were quantified. The signal loss caused by the devices was approximately four times greater than the size of the device.
Accretion processes with linear particle trajectories

Abstract Clusters containing up to 250,000 particles or occupied lattice sites have been generated using several linear particle trajectory accretion models. In two-dimensional simulations we find that effective fractal dimensionalities are greater than 1.95 in all of these models. The apparent values of the fractal dimensionality increase slowly with increasing cluster size and it seems probable that the limiting (large cluster size) dimensionalities have a value of 2.0. In three-dimensional simulations we find that the fractal dimensionality is greater than 2.8 and its limiting (large size) value is probably 3.0. Our results indicate that clusters generated via linear particle trajectories are not uniform on short-length scales but are uniform or almost uniform on longer-length scales.
Evaluating fuel complexes for fire hazard mitigation planning in the southeastern United States

Abstract Fire hazard mitigation planning requires an accurate accounting of fuel complexes to predict potential fire behavior and effects of treatment alternatives. In the southeastern United States, rapid vegetation growth coupled with complex land use history and forest management options requires a dynamic approach to fuel characterization. In this study we assessed potential surface fire behavior with the Fuel Characteristic Classification System (FCCS), a tool which uses inventoried fuelbed inputs to predict fire behavior. Using inventory data from 629 plots established in the upper Atlantic Coastal Plain, South Carolina, we constructed FCCS fuelbeds representing median fuel characteristics by major forest type and age class. With a dry fuel moisture scenario and 6.4 km h −1 midflame wind speed, the FCCS predicted moderate to high potential fire hazard for the majority of the fuelbeds under study. To explore fire hazard under potential future fuel conditions, we developed fuelbeds representing the range of quantitative inventory data for fuelbed components that drive surface fire behavior algorithms and adjusted shrub species composition to represent 30% and 60% relative cover of highly flammable shrub species. Results indicate that the primary drivers of surface fire behavior vary by forest type, age and surface fire behavior rating. Litter tends to be a primary or secondary driver in most forest types. In comparison to other surface fire contributors, reducing shrub loading results in reduced flame lengths most consistently across forest types. FCCS fuelbeds and the results from this project can be used for fire hazard mitigation planning throughout the southern Atlantic Coastal Plain where similar forest types occur. The approach of building simulated fuelbeds across the range of available surface fuel data produces sets of incrementally different fuel characteristics that can be applied to any dynamic forest types in which surface fuel conditions change rapidly.
Electronic Energy Transfer between Non-conjugated Chromophores

MODEL compounds incorporating inflexible, insulating nor-bornane frames to hold donor and acceptor chromophores with a fixed separation distance and orientation have proved useful in energy transfer studies1–10. We report the investigation of two new sets of such compounds. Each set consists of donor and acceptor chromophores held: (a) 7.5 A apart by a single-bridged norbornane frame; and (b) 10 A apart by a double-bridged exo-endo-1,4 : 5,8-dimethano-1,2,3,4,4a,5,6,7,8, 8a-decahydronaphthalene frame. For reference purposes, model compounds containing each individual donor and acceptor chromophore on a single-bridged frame were also prepared.
High-resolution tomography of objects with access to a single side

We are developing a technique which will enable us to obtain high-contrast, high-spatial resolution, three-dimensional images in opaque objects. Our only constraint will be the radiation source and detector(s) located on the same side of the object. Our goal is to obtain images with a spatial resolution of approximately 1 mm at depths of 10 mm and approximately 3 mm at depths of 30 mm in materials of moderate density (brass, steel, etc.). Our technique uses a highly-collimated beam of monochromatic gamma rays and a slit collimated high- resolution, high-efficiency, coaxial germanium spectrometer. If the geometry is well known, the spectrum of Compton scattered radiation can be used to map out the density as a function of depth. By scanning the object in two dimensions, a full three-dimensional image of the electron density can be reconstructed. The resolution is, of course, dependent on the incident beam collimation and the energy resolution of the spectrometer. For our system, we anticipate a resolution of about 1 mm3. The apparatus, reconstruction algorithms, and current data verifying our predictions are presented here. Also included are the details on how our system can be modified to increase the efficiency by over two orders of magnitude.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Testing for clustering in record linkage databases

One way to identify an excess risk of an adverse event during drug exposure is to use administrative, medical, and pharmacy records data, such as Medicaid or HMO (Health Maintenance Organization) records, to compare the relative frequency of the suspect event in exposed and unexposed periods. Such estimates can be seriously biased if there is clustering in patient visits to physicians and pharmacies. This paper presents two simple tests for determining whether the patient visit dates in such a database are Poisson processes of visits or clustered processes. The paper shows that this test is quite powerful at detecting both clustered sequences and nearly regular sequences of visits. Finally, it gives a straightforward SAS program which will carry out the tests.
Evaluation of fire resistance of rectangular steel columns filled with fibre-reinforced concrete

Experimental and theoretical studies that have been carried out to predict the fire resistance of rectangular hollow steel columns filled with fibre-reinforced concrete are presented in this paper. A numerical model to calculate the temperatures, deformations, and the fire resistance of loaded, rectangular, hollow steel columns filled with steel-fibre-reinforced concrete is described. Predictions from the numerical model are compared with experimental data. The results indicate that the model is capable of predicting the fire resistance of square hollow steel columns filled with fibre-reinforced concrete with an accuracy that is adequate for practical purposes. The model can be used to evaluate the fire resistance of rectangular steel columns filled with steel-fibre-reinforced concrete for any value of the significant parameters, such as load, column section dimensions, column length, concrete strength, and aggregate type in concrete, without the necessity of testing. Resume : Cet article prOsente des Otudes thOoriques et expOrimentales effectuOes afin de prOdire la rOsistance au feu de colonnes rectangulaires creuses en acier remplies de bOton armO de fibres. Un modle numOrique calculant les tempOratures, les dOformations et la rOsistance au feu de colonnes creuses en acier remplies de bOton armO de fibres et soumises ‡ un chargement, est dOcrit. Les prOdictions du modle numOrique sont comparOes aux donnOes expOrimentales. Les rOsultats indiquent que le modle est capable de prOdire la rOsistance au feu des colonnes carrOes creuses en acier remplies avec du bOton armO de fibres avec une prOcision convenable ‡ des fins pratiques. Le modle peut Ovaluer la rOsistance au feu de colonnes rectangulaires en acier remplies de bOton armO de fibres utilisant niimporte quelle valeur pour les paramtres significatifs, tels que la charge, les dimensions de la section de la colonne, la longueur de colonne, la rOsistance du bOton et le type de granulats du bOton, sans nOcessiter des essais expOrimentaux.
Tallness versus shrinkage: do women shrink with age or grow taller with recent birth date?

This paper presents evidence that much of the high rate of age-related height loss in women reported in cross-sectional studies is actually a cohort effect rather than an aging effect. Data from a large cross-sectional study of healthy, white American women indicate that there has been a gain in peak adult height of 1.0 cm per decade for several decades from 1900 through 1965. Data from the HES, HANES I, and HANES II studies concur on this point. By contrast, data from a longitudinal study of 191 healthy white U.S. women show only a trivial rate of decline from peak adult height in the fifth and sixth decades of life. In an unselected population, some apparent height loss with age is probably due to disease processes, such as vertebral collapse. Caution is needed in using aging to interpret differences in height and in height-dependent variables, such as bone density, in cross-sectional studies.
When parents are deaf versus hard of hearing: patterns of sign use and school placement of deaf and hard-of-hearing children.

This paper investigates the importance of knowing whether or not deaf and hard-of-hearing students have one or more deaf or hard-of-hearing parents. As noted by Mitchell and Karchmer (2004), deaf and hard-of-hearing school-age children and youth in the United States with at least one parent identified as ‘‘hearing impaired’’ are nearly evenly split between having at least one deaf parent and having at least one hard-of-hearing parent. However, there is no literature on the importance, if any, of this distinction. Findings from the investigation reported herein suggest that the distinction between having a deaf versus a hard-ofhearing parent is quite substantial, particularly as it pertains to the use of signing in the home. Further, signing in the home, which is reliably predicted by parental hearing status, is a significant predictor of the school setting in which the student is currently placed and the instructional use of signing in the classroom. Limitations related to the available measure of parental hearing status are discussed.
Economic Value of Long-Lead Streamflow Forecasts for Columbia River Hydropower

Recent advances in long-lead climate forecasting have made it possible to produce useful streamflow forecasts for the Columbia River basin roughly six months earlier than current forecasts that rely on snowpack measurements. The resulting increase in forecast lead time facilitates considerable improvements in system operating performance, especially in years of expected above average flows. In the current reservoir operating system, the so-called “critical” and “assured refill” rule curves that restrict releases for hydropower generation in the period from August to December are based on the critical (most severe low flow) and third lowest flow sequences of record, respectively. These rule curves provide appropriate protection of energy capacity and reservoir refill in extreme low flow conditions, but are restrictive in normal and high flow years until midwinter when operational streamflow forecasts based on observed snowpack become available, and the climatological constraints are relaxed to account for expected summer streamflows. The use of long lead time streamflow forecasts allows current operating constraints to be relaxed to account for expected summer streamflows. The use of long lead time streamflow forecasts allows current operating constraints to be relaxed in years when there is a high likelihood of ample streamflow. In these years, more spot market energy sales can be made in the late summer and fall/early winter because of increased available water for releases, and spill from reservoirs in wet years is also reduced. Reservoir model simulations using alternative reservoir rule curves based upon retrospective long-lead streamflow forecasts from water years 1931 to 1987 show that the proposed alternative operating system based on climate forecasts can increase nonfirm energy production from the major Columbia River hydropower dams by as much as 5.5 million MW/h/year, resulting in an average increase in annual revenue of approximately $153 million per year in comparison with the status quo. Other uses of the Columbia River are largely unaffected by the proposed changes in the operating system. In particular, firm energy, the reliability of storage reservoir refill, and the frequency of meeting of streamflow targets for salmon protection would be essentially unchanged in comparison with the status quo. The increased hydropower revenue is therefore directly attributed to use of long-lead forecast information and does not represent a trade-off among other management objectives.
MRI measurement of liver regeneration in mice following partial hepatectomy

Improvements in noninvasive imaging modalities are crucial for preoperative in vivo assessments of liver condition and potential for regeneration after liver resection for removal of liver tumors. To that end, an MRI study of liver regeneration in mice following partial hepatectomy is described and validated. Hepatic volumes were accurately measured from contrast-enhanced, gradient-echo images of the liver. Regeneration curves were constructed for a series of mice (N = 6) from a longitudinal MR study, with images collected 1, 2, 3, 4, 5, and 9 days following surgery. We validated the MR method by correlating serial MR-measured volumes with liver wet weight. The success of this method will enable future studies to better elucidate the factors that affect regeneration, and help to optimize the timing and dosing of chemotherapeutics to minimize their deleterious effects on liver regeneration.