cssi/SciSciGPT-SciSciNet huggingface dataset:
An experimental investigation of gas flow in a scale model of a fluidized-bed combustor

Abstract An ambient temperature model was constructed to simulate the flow within the TVA 20 MW fluidized-bed combustor pilot plant. Scaling laws, verified by earlier results, allowed the hot combustor to be modeled by an ambient temperature bed of one-quarter linear scale. A fiber optic bubble probe, supplemented by visual observations, was used to make detailed studies of bubble characteristics within the bed at moderate to high superficial velocities. Bubble properties were measured within horizontal tube bubbles as well as in the gaps between neighboring tube bundles. The gas flow associated with the motion of visible bubbles was only about 20% of the excess gas superficial velocity for all cases. The measured bubble characteristics and the observed height of particle plumes in the freeboard caused by erupting bubbles were combined with a simple analysis of particle dynamics to estimate the gas throughflow velocity through erupting bubbles. The estimated throughflow velocity allowed an approximate balance to be achieved for the overall gas flow rate in the bed.
Gender matters: Constructing a model of adolescent sexual health

This article illustrates the construction of a new model of adolescent sexual health, one that addresses the complex relationships between gender and adolescent sexuality. A review of sexual health models highlights the absence of gender; in contrast, research illuminates the significance of gender. This article describes the process of building a model of sexual health explicitly for girls, guided by feminist research on adolescent girls' sexuality and a "web of theories". It also describes the unanticipated challenges of making a companion model for boys and the ensuing shift from a gender-specific approach to an integrated gendered model of adolescent sexual health. Gender complementarity is defined and forwarded as a way to incorporate gender into a model of adolescent sexual health.
Optimizing burrows-wheeler transform-based sequence alignment on multicore architectures

Computational biology sequence alignment tools using the Burrows-Wheeler Transform (BWT) are widely used in next-generation sequencing (NGS) analysis. However, despite extensive optimization efforts, the performance of these tools still cannot keep up with the explosive growth of sequencing data. Through an in-depth performance analysis of BWA, a popular BWT-based aligner on multicore architectures, we demonstrate that such tools are limited by memory bandwidth due to their irregular memory access patterns. We then propose a locality-aware implementation of BWA that aims at optimizing its performance by better exploiting the caching mechanisms of modern multicore processors. Experimental results show that our improved BWA implementation can reduce last-level cache (LLC) misses by 30% and translation look aside buffer (TLB) misses by 20%, resulting in up to 2.6-fold speedup over the original BWA implementation.
The Incidence of Spontaneous Tumors in Female Mice (Breeders) of the CBA Strain

The incidence of spontaneous tumors in female mice (breeders) of the CBA strain has been indicated in three recent papers (1–3). The purpose of dividing the observations into a series of individual experiments has been to eliminate any possible genetic variability as a source of varying tumor incidence. So far, two series (1, 2) of mice have been used for a moderate degree of breeding and then placed in reserve on a “mixed oatmeal diet”; a third series (3) of 63 females was similarly treated but continued throughout life on a commercially prepared diet. The incidence of spontaneous tumors in the two series of mice kept on the oatmeal diet was similar (5.6 per cent and 3.7 per cent; average 4.8 per cent). The third series, kept on the commercial diet, showed a somewhat higher incidence, 12.7 per cent. In order to substantiate this possible difference in cancer incidence on different diets, a fourth series of 81 CBA females was placed in reserve between Dec. 13, 1934, and May 17, 1935, and continued on the commercial diet. Experimental Observations The ages of the 81 mice when the first litters were born are given in Chart 1. The average was 104.6 days. The ages at which the mice were separated from males and placed in reserve are given in Chart 2 (solid line). Of the 81 female mice of the present series, 30 developed spontaneous tumors (Table I). Eighteen developed carcinoma of the mammary gland at an average age of 655.6 days; 6 developed hepatoma (4) at an average age of 695.0 days; 4 carcinoma of the ovary at an average age of 765.0 days; 2 primary carcinomas of the lungs at an average of 822.5 days; 1 an osteoid giant-cell sarcoma in the region of the ribs, at 925 days of life. Mouse S110171 was the only one in the series with more than one type of primary tumor. She developed a carcinoma of the mammary gland at 557 days of life. Autopsy at 590 days disclosed a hepatoma also. The incidence of spontaneous tumors in this series is, therefore, 37.0 per cent.
Inferring 3D Structure from Image Motion: The Constraint of Poinsot Motion*

Monocular observers perceive as three-dimensional (3D) many displays that depict three points rotating rigidly in space but rotating about an axis that is itself tumbling. No theory of structure from motion currently available can account for this ability. We propose a formal theory for this ability based on the constraint of Poinsot motion, i.e., rigid motion with constant angular momentum. In particular, we prove that three (or more) views of three (or more) points are sufficient to decide if the motion of the points conserves angular momentum and, if it does, to compute a unique 3D interpretation. Our proof relies on an upper semicontinuity theorem for finite morphisms of algebraic varieties. We discuss some psychophysical implications of the theory.
Effects of sulfuric acid aerosol inhalations

Submicrometer H2SO4 droplets can affect pulmonary functions in humans. The lowest concentration which has been reported to produce a statistically significant effect on pulmonary mechanics is 1 mg/m3. Effects on tracheobronchial mucociliary clearance of inert particles were observed in our laboratory at much lower concentrations. For ten nonsmoking humans exposed for one hour via nasal mask to 0.1 mg/m3 of H2SO4, the mean bronchial clearance half-time was reduced by 38% (p less than 0.02) while for 1 mg/m3, it was increased by 48% (p less than 0.03). Four donkeys exposed for 1 hour daily to 0.1 mg/m3 for six months developed clearance abnormalities which persisted for at least three months after the last exposure. The patterns of mucociliary clearance responses to H2SO4 are similar to those seen previously in humans and donkeys following exposure to cigarette smoke, a known causal factor for chronic bronchitis.
Do ring doves copulate more than necessary for fertilization

Abstract It has been suggested that in monogamous species a female will protect herself from mate desertion by withholding copulation until she is assured of the male's parental care. The ring dove ( Streptopelia risoria ) is a monogamous species whose females copulate with males frequently during prelaying phase. In this study we demonstrate that copulations did not result in fertilization unless they took place contiguous to the pre-ovulatory hormonal state of the female which was brought about only if the male courted the female for a sufficient period of time. Thus, in this species, ovulation and therefore fertilization was dependent on the male's presence regardless of how often copulation took place, insuring that the male must make a time commitment to guarantee paternity.
Synthesis and characterization of low valent complexes of molybdenum containing the tridentate ligand PhP(CH2CH2PPh2)2 (TRI)

Abstract Reduction of [MoCl 3 (TRI)] with sodium amalgam in the presence of potential ligands results in the formation of a series of new complexes containing η 3 -TRI. These include [Mo(η 6 -C 6 H 5 R)(TRI)] (where R = H, Me, MeO), [Mo(η 5 -C 5 H 5 )(H)(TRI)] [Mo(TRI)(P(OR) 3 ) 3 ] (where R = Me, Et), and fac -[Mo(N 2 )(TRI)(PMe 3 ) 2 ]. Protonation of the arene complexes results in the formation of both mono- and diprotonated complexes.
Pure and Simple Politics: The American Federation of Labor and Political Activism, 1881–1917

Scholarship on American labor politics has been dominated by the view that the American Federation of Labor, the dominant labor organization, rejected political action in favor of economic strategies. Based upon extensive research into labor and political party records, this study demonstrates that, despite the common belief, the AFL devoted great attention to political activity. The organization's main strategy, however, which Julie Greene terms 'pure and simple politics', dictated that trade unionists alone should shape American labor politics. Exploring the period from 1881 to 1917, Pure and Simple Politics focuses on the quandaries this approach generated for American trade unionists. Politics for AFL members became a highly contested terrain, as leaders attempted to implement a strategy which many rank-and-file workers rejected. Furthermore, its drive to achieve political efficacy increasingly exposed the AFL to forces beyond its control, as party politicians and other individuals began seeking to influence labor's political strategy and tactics.
Numerical simulation of the tensile modulus of nanoclay‐filled polymer composites

A numerical simulation model that incorporates three phases, polymer matrix, interlayer, and clay platelet, was developed to predict the tensile modulus of nanoclay-filled polymer composites. The interlayer was introduced to account for the fact that the mechanical properties of the polymer near the clay surface are different from those of the polymer matrix. The effects of the properties of interlayers, the structure of clay clusters, and platelet distributions upon the modulus of elasticity of the nanocomposites, were studied. The simulation results show that a decrease in the interlayer modulus, as well as an increase in the interlayer thickness, would decrease the modulus of the nanocomposites. Furthermore, it was found that the maximum strain, located in the interlayer near the end of the clay platelet, increases significantly with decreasing interlayer modulus. The effects of the distribution of clay platelets upon composite modulus were interpreted in terms of two parameters, platelet overlap length, and the lateral distance between platelets. Comparison of simulation results with experimental data from the literature has confirmed the reliability of the numerical simulation method used in the present study. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2391–2406, 2004
Perfusion of Free Flaps with Heparinized Whole Blood During Ischemic Storage

This study was designed to investigate the use of heparinized whole blood as a perfusate for extending the tolerable ischemic interval of free flaps. Unilateral free groin flaps stored at 20 degrees for 30 hr were used in four groups of 12 rats each. One group served as a control while a second involved systemic heparinization immediately prior to raising the flap for storage. The third and fourth groups underwent a brief perfusion (10-30 min) with anticoagulated whole blood midway through the ischemic interval (15 hr); one of these groups involved temporary revascularization to the arterial system of a donor heparinized rat. The fourth group received hand-perfused anticoagulated (with heparin and citrate) whole blood administered through a cannula placed in the flap artery. After the 30-hr interval, flaps were replanted to the original groin site with standard microvascular technique. Percentages of the numbers of surviving flaps were: 8 percent for controls, 58 percent for both preheparinized and donor-perfused flaps, and 92 percent for the hand-perfused group. The authors conclude that anticoagulated blood within the flap vasculature during ischemic storage can improve the chance for viable reperfusion after replantation, and may offer a safeguard against the no-reflow phenomenon after extended ischemia.
Sleep duration and overweight in adolescents: self-reported sleep hours versus time diaries.

OBJECTIVE. Studies of children have found an inverse association between sleep duration and overweight on the basis of parental report of sleep duration. Studies in adolescents have been inconsistent but used varied measures of sleep. We used a nationally representative sample of adolescents that included 2 different measures of sleep duration (24-hour time diaries and self-reported usual sleep hours) to examine whether the association with overweight is sensitive to how sleep is measured in a single study population. We expected that the 2 measures of sleep would be strongly correlated and that the time-diary sleep would be more strongly associated with overweight risk because it is likely the more accurate measure of sleep. METHODS. In 2001–2002, adolescents from the Child Development Supplement of the Panel Study of Income Dynamics completed 24-hour time diaries on a random weekday and weekend. Adolescents also self-reported average sleep duration. Both sleep measures were categorized into quartiles. Height and weight were measured, and a BMI z score for age and gender was calculated. Overweight was defined as above the 95th percentile. RESULTS. The final sample included 767 male and 779 female subjects who were aged 10 to 19 years. Mean time-diary sleep was nearly 9 hours on weekdays and >10 hours on weekends. Mean self-reported sleep duration was 8 hours. Time-diary sleep and self-reported sleep were weakly correlated. Time-diary sleep was not significantly associated with overweight. Self-reported sleep was associated with overweight, but the association was not linear. When both sleep measures were included in the same model, their effects on overweight were independent. CONCLUSIONS. The weak correlation between self-reported sleep and time-diary sleep and the independence of their associations with overweight raise questions about what different measures of sleep duration in adolescents represent.
Sesquiterpene lactones and lignanes from Rudbeckia species

Abstract Rudbeckia grandiflora , R. subtomentosa , R. nitida var. texana , R. scabrifolia and R. maxima were investigated for their secondary constituents. Rudbeckia subtomentosa leaves afforded the known sesquiterpene lactones 4- O -desacetylligulatine C, and ligulatine C; the flowers provided costunolide, santamarine, reynosin, the flavonol eupatolin plus a mixture of β-sitosterol and stigmasterol; the roots gave costunolide, 11,13-dihydrocostunolide, gazaniolide, isogazaniolide, tamaulipin A angelate, caryophyllene, caryophyllene oxide and β-selinene. Rudbeckia nitida var. texana , R. scabrifolia and R. maxima gave the lignanes (+)-pinoresinol dimethyl ether and yangambin. The germacrolide tamaulipin A angelate, was the major constituent of root extracts of R. grandiflora . Structure and stereochemistry of the new lactones were elucidated by spectroscopic methods. The molecular structures of gazaniolide
Color transitional dyes as indicators of ionic boundaries in sodium dodecylsulfate polyacrylamide gel electrophoresis

Several dyes were evaluated for their potential use as indices of ionic boundaries and pH discontinuities during polyacrylamide gel electrophoresis (PAGE). Dye selection was based largely upon color transition over the pH intervals present in the commonly used Tris-HCl-glycine buffer systems. In the absence of sodium dodecylsulfate (SDS) nitrazine yellow, cresol purple, cresol red, and phenol red had relative mobilities (relative to the chloride boundary; RC1) of 1.00 at 20% polyacrylamide concentration (% T) compared to bromophenol blue (BPB) for which RC1=0.77. The homologue of BPB, 3, 4, 5, 6-tetrabromophenolsulfonephthalein (TBPS), exhibited a useful color transition over the pH 6.6-8.2 range but was an equally poor indicator of the chloride boundary at 20% T in the absence of SDS (RC1=0.73). The RC1 of other dyes was increased in the presence of SDS, particularly the cationic dye neutral red which complexes with micellar but not monomeric SDS. In the presence of SDS, all dyes except neutral red exhibited RC1 of 1.00 at 15% T, whereas only neutral red and nitrazine yellow had RC1 values of 1.00 at lower gel concentrations. Partial characterization of SDS, in terms of RC1 and zone broadening, was performed in a system devoid of extraneous SDS in the gel or electrolytes.
Simultaneous Multitemperature Measurements of Thermal Diffusivity and Composition

It has been well established that thermal forcing of disordered multielement metallic alloys results in permanent modification of their thermal transport properties. The mechanism depends on the detail of heating and its duration, and entails rearrangement of the spatial distribution of constituent atoms within the material proper. It presents a serious complication in developing a body of properties data as a function of temperature because establishment of a thermal state for a specimen is often cast into question. A new general technique is presented for simultaneous multiple-temperature measurements of thermal diffusivity and local composition for a single specimen. The specimen is heated steeply into a state of temperature nonuniformity. The measurement is carried out by time-resolved spectroscopy of single-shot laser-produced plasma (LPP) plume emissions; analysis is made of the emissions as a function of position within the laser focal area. The procedure for analysis is presented together with the results for 80 mass% Ni-20 mass% Cr Nichrome specimens.
Metabolic Profiling of the Skin to Monitor the Onset and Progression of Squamous Cell Carcinoma through Time- and Wavelength-Resolved Fluorescence Lifetime Imaging

Every year millions of people in the United States are affected by skin cancer, and like other cancers, the key to an effective treatment is early detection and monitoring of disease progression. To this end, we have used intensity-, time-, and wavelength-resolved multiphoton microscopy to measure changes in cellular metabolism. By analyzing the fluorescence emission of metabolic coenzymes such as the reduced form of Nicotinamide Adenine Dinucleotide (NADH) and the oxidized form of flavin cofactors, slight changes in the mitochondrial microenvironment and cellular metabolism can be quantified. We used dual-channel fluorescence lifetime imaging (FLIM) to quantify metabolic changes both within and between high- and low-HER2 expressing squamous cell carcinoma cell lines (SCC-74B and SCC-74A, respectively). Chemically-induced changes in the metabolic state led to measureable changes in lifetime distributions and fluorescence intensities within each cell line. In addition, SCC-74A and −74B could clearly be distinguished on the basis of the fluorescence intensity dynamic range (difference between uncoupled and inhibited metabolic states) and lifetime distributions. The metabolic imaging technique has also been adapted to living skin in vivo. In particular, fluorescence signals originating from metabolically active and in-active sources are identified and separated based on a combination of the two-photon-excited fluorescence excitation/emission spectra and second harmonic generation (SHG).This study was conducted at the Creighton University Integrative Bio-Imaging Facility (CU-IBIF) and was supported by NIH DC 02053, NSF-EPSCoR EPS-0701892 (CFD 47.076), NIH P20 RR16469 (NCRR) and 5P20GM103427 (NIGMS) as well as the Ferlic Summer Research Program at Creighton University.
On essential information in sequential decision processes

This paper provides sufficient conditions when certain information about the past of a stochastic decision processes can be ignored by a controller. We illustrate the results with particular applications to queueing control, control of semi-Markov decision processes with iid sojourn times, and uniformization of continuous-time Markov decision processes.
Stability of Displacement Fronts in Porous Media Growth of Large Elliptical Fingers

A theoretic analysis is presented for growth of a single, large elliptical finger in a porous medium. The objective is to obtain an understanding of how large fingers develop once a displacement front has become unstable. The results provide information beyond that available from linear analysis which has been used in most previous work and which applies only to infinitesimal perturbations. Separate analyses are given for finger growth during instability of the front accompanying displacement on one immiscible fluid by another; the combustion front in a dry, forward combustion process; a condensation front; and the combustion front in dry, reverse combustion as employed in the linking step of underground coal gasification. 19 references.
Performance prediction of array arrangement on ducted Composite Material Marine Current Turbines (CMMCTs)

Abstract The present paper deals with the flow distribution and power generation of ducted Composite Material Marine Current Turbines (CMMCTs) using Computational Fluid Dynamics (CFD). The hydrodynamic performance of CMMCTs in different array arrangement and the influence on each other were investigated and discussed. The numerical results showed the detail of flow distribution in arrays and provided an insight into the design and operation of CMMCTs in order to improve the technical performance. The methodology in the present study may be used to optimize the arrangement of the CMMCTs for possible maximum power generation.
Replicability of structural models of the Edinburgh Postnatal Depression Scale (EPDS) in a community sample of postpartum African American women with low socioeconomic status.

The Edinburgh Postnatal Depression Scale (EPDS) is increasingly used in public health and social service programs serving postpartum women of racially, ethnically, and socioeconomically diverse backgrounds at risk for depression. However, we know little about its factor structure across groups of women with implications for measuring symptom levels in research. This study evaluated the underlying structure of the EPDS using a confirmatory factor analyses model comparison approach of five factor models from the literature in a purposive community sample of 169 postpartum African American women of low socioeconomic status. Participants were identified through an exhaustive review of local health department program files dated August 2006 to August 2010 in a Midwestern state of USA. Tuohy and McVey’s (Br J Clin Psychol 47:153–169, 2008) three-factor model (depression, anxiety, and anhedonia) demonstrated the best fit to the data with a nonsignificant Satora–Bentler scaled chi-square value (21.70, df = 24, p = 0.60) and the lowest root mean square error of approximation (0.00) and standardized root mean square residual (0.05) values. The results call for further study of the factor structure of the EPDS in other racial and ethnic groups and cautious use of the EPDS among perinatal women of racially, ethnically, and socioeconomically diverse backgrounds until its factorial invariance is better understood.
Viscoelastic analysis of FRP strengthened reinforced concrete beams

Abstract External bonding of FRP plates or sheets has become a popular method for strengthening reinforced concrete structures. Stresses along the FRP-concrete interface are critical to the effectiveness of this technique because high stress concentration along the FRP-concrete interface can lead to the FRP debonding from the concrete beam. Although the short-term stress distribution along the FRP-concrete interface has been studied extensively, very few studies have been conducted on the long-term stress distribution, which closely simulates the behavior of the structure during the service-life. In this study, we develop a viscoelastic solution for the long-term interface stress distribution in a FRP plate strengthened reinforced concrete beam. In this solution, the RC beam and the FRP plate are modeled as elastic materials; while the adhesive layer is modeled as a viscoelastic material using the Standard Linear Solid model. Closed-form expressions of the interface stresses and deflection of the beam are obtained using Laplace transform and calculated using the Zakian’s numerical method. The validation of this viscoelastic solution is verified by finite element analysis using a subroutine UMAT based on the Standard Linear Solid model.
Chromosome abnormalities in erythroleukemia

Erythroleukemia (EL) is a heterogeneous disease in terms of cell type affected, chromosome abnormalities found in the malignant clone, and clinical course. In this article, cases of erythroid EL from the recent medical literature are reviewed using cytogenetic criteria to distinguish such cases from those of myeloid EL. Although most patients with erythroid EL were elderly men, 20% of the cases occurred in the under-3 age group, where boys and girls were equally affected. Chromosomes 5 and 7 were found to be lost or partially deleted in two thirds of the adult patients only, but not in the pediatric patients; this suggests that EL is associated with cumulative mutagen exposure in adult patients only. It is proposed that cytogenetic criteria may be of use prospectively in distinguishing patients with erythroid EL from those with myeloid EL.
The dependence of open field burning emissions and plume concentrations on meteorology, field conditions and ignition technique

A program of field and laboratory measurements of emissions from the burning of agricultural residues (primarily cereal straw and stubble) and plume behavior is described. Relationships investigated include the dependence of total emissions and plume concentrations on fuel management, field ignition technique and ambient meteorological conditions. Total particulate emissions (by mass) were found to increase strongly with increasing residue moisture content but are reduced to one half through the use of a backfire field ignition technique versus the head fire ignition method. Increased emissions from headfires is attributable to smoldering in the burned over areas. Backfire fuel consumption rates are typically about one-fifth that for headfires, resulting in a further reduction of particle concentrations in backfire plumes. Increased fuel loading reduces emissions, especially for headfires. The mass median diameter of particles from either fire ignition technique is less than 0.2 μm and in the average about one half of these particles are chloroform soluble. CO and gaseous hydrocarbon emissions were also found to be directly proportional to residue moisture content, but independent of field ignition technique. Plume rise is maximized (ground level concentration minimized) by using headfires in light winds (<4 m s−1). At higher wind speeds, limited plume rise and increasing fumigation increases ground level concentrations but this can be minimized through the use of backfires. As the effluent plume ages, the size spectrum shifts to smaller diameters suggesting significant evaporation with time. The results of fuel drying studies and cost analyses for the various techniques are also presented.
Role of repeat fine-needle aspiration biopsy (FNAB) in the management of thyroid nodules.

The purpose of the present study was to determine the role of repeat fine-needle aspiration biopsy (FNAB) in the evaluation of thyroid nodules initially classified as “nondiagnostic” due to limited cellularity or as “indeterminate for neoplasm.” We reviewed a cohort of 431 patients (352 females, 79 males; average age 50 yr); 237 patients were classified as “nondiagnostic” due to limited cellularity and 194 as “indeterminate for neoplasm” over a 3-yr period (1999–2002). Repeat FNAB under ultrasound guidance was performed in 226 patients (226/431, 52%); surgical pathology results were available in 101 patients. Repeat FNAB diagnoses were: benign 70 (31%), follicular/Hurthle cell neoplasm 62 (27%), suspicious for papillary carcinoma 25 (12%), malignant 17 (7%), and nondiagnostic 52 (23%) cases. Surgical follow-up was available in 101 (45%) patients; malignancy was identified in 50 (49%) patients. The malignancy rate was 51% and 48% in cases in which initial FNAB was nondiagnostic and indeterminate for neoplasm, respectively. There were no false-positives and all malignant cases undergoing surgery were found to be malignant. This study demonstrates that repeat FNAB is warranted in patients with thyroid nodules diagnosed on initial FNAB as nondiagnostic and indeterminate for neoplasm since it can yield a definitive diagnosis in the majority of cases with an overall malignancy rate of 49%. Diagn. Cytopathol. 2003;29:203–206. © 2003 Wiley-Liss, Inc.
Factors Controlling Successful Formation of Mixed-Matrix Gas Separation Materials

Prior work has suggested simple guidelines for matching transport characteristics of materials to form high-performance mixed-matrix materials for gas separation. Such materials comprise a dispersion of molecular sieving particles in a properly selected matrix polymer phase. Recent work has shown that these simple criteria are necessary but not sufficient to achieve the desired properties. The analysis presented here shows the need to optimize the transport properties of the interfacial region, i.e., the region between the bulk polymer and dispersed sieve phases. Guided by the need to optimize both the transport properties of the interfacial region and the matrix material selection criteria noted above, a new paradigm is recommended for matrix phase selection. The practicality of the paradigm is validated by the formation of mixed-matrix membranes with an appropriate polymer and sieve. These materials lead to the attractive predicted performances at low loading. For success at higher loading a zeolite “pr...
Effect of lift with roll rate variation on re-entry vehicle impact

The effect of lift with roll rate variation on the impact of re-entry vehicles is treated analytically. The equations of motion of a vehicle experiencing lunar motion at small angle of attack are integrated assuming the roll rate history can be approximated with a series of linear segments. Each segment occurs over a sufficiently short interval of time that the trajectory properties can be assumed constant. The result is a closed-form solution expressing the resulting impact deviation from the zero-lift case as a function of the zero-lift trajectory characteristics and the roll rate history. The effect of a single linear roll rate variation between arbitrary initial and final roll rates on impact is derived from this general result. Roll through zero between roll rates of large magnitude but opposite sign, and roll acceleration of infinite magnitude between arbitrary roll rates are presented as special cases. An example problem involving a single linear variation is treated and compared with results obtained using a sixdegree-of-freedom trajectory simulation program. These results compare to within 5% typically, with none of the differences exceeding 13%.
Multimedia-Supported Metaphors for Meaning Making in Mathematics

We examined a number-line metaphor presented using interactive multimedia as a means of helping students build connections between an arithmetic procedure and their existing conceptual knowledge. Elementary school children learned to add and subtract signed numbers through a computer-based multimedia program over 4 training sessions. Participants received 64 example problems presented only in symbolic form (single-representation [SR] group) or in symbolic, visual, and verbal forms (multiple-representation [MR] group). In Experiment 1, compared to the SR group, the MR group (a) showed a larger pretest-to-posttest gain for high-achieving students but not for low-achieving students, (b) showed a greater gain on difficult problems but not easy problems, (c) learned faster during training, and (d) showed a greater pretest-to-posttest reduction in the use of conceptual bugs reflecting conceptually confusion between negative signs and subtraction operators. In Experiment 2, high spatial ability students in the M...
Nanocatalysis: Selective Conversion of Ethanol to Acetaldehyde Using Mono-atomically Dispersed Copper on Silica Nanospheres

Abstract Silica nanospheres, d ∼30 nm, are prepared at elevated temperature from an Si/SiO 2 mixture. Under ambient conditions, the high population of surface hydroxyl on these nanospheres, confirmed by FTIR spectroscopy, is probed by decorating the surfaces of the spheres with the metal complex copper (II) acetylacetonate: Cu(acac) 2 . This metal complex, known to be anchored by the surface SiOH species, is converted into the active catalyst by thermolysis of the ligands. The resulting monatomic copper distribution forms a selective catalyst whose conversion efficiency appears to be at least comparable to if not better than CuO/fumed silica. In contrast to the fumed silica, the preparation of this catalyst support is environmentally benign.
Fine structure of the down feather during its early development.

The down feather of the chick embryo has been examined by electron microscopy during three distinct stages of its early development; the presumptive stage, represented by dorsal skin of an area from which the feather organ will arise; the thickening stage, during which areas of the basal epidermis form spurs projecting into the mesenchyme, and the latter condenses under a thickened area of the epidermis; the elevation stage, at which time the basal epidermis flattens, the entire epidermis increases in thickness, and the underlying mesenchyme becomes more compact. As development proceeds the rough endoplasmic reticulum of the epidermal cells dilates, but during the elevation stage begins to flatten, and Golgi is observed with increasing frequency. The mitochondria do not appear to differ except for those in the periderm during the presumptive stage, in which case they reveal a vacant matrix and irregular cristae. Evidence is presented for actual contact between basal epidermal spurs and filopodia of cells within the mesenchyme, some of which contain numerous vesicles. The basal epidermal spurs are also seen in intimate association with collagen and anchor filaments and a network of reticulin. Evidence is also presented for the presence of neuronal elements within the mesenchyme during the thickening stage. Cross sections of cell processes within the condensations of the mesenchyme resemble unmyelinated nerve fibers, and cross sections of filopodia similar to arborizing axons abound at and within the basal lamina of both the thickening and elevation stages. Further support for the presence of nerve fibers within the mesenchyme comes from positive staining results with Bodian's and Ungewitter's methods. This comparative study of three stages of early development of the feather organ serves as a basis for more detailed investigations of each stage.
Five challenges for China in the 1990s

There are many economic challenges facing China in its transformation to a market economy. Professor Dean discusses five of the most important of these challenges and the opportunities which they present.
Research and development activities on refractory ceramics

Abstract A relatively small fraction of the total number of articles published annually (1,500–2,000) on refractory themes represent basic studies and the group sampled here does not well reflect the overall commercial activity in refractories. For example, a very large effort is expended in the engineering of new methods of conveying and emplacing concretes and in repairing all types of refractories. However, the larger refractory companies are restructuring ‘Research and Development’ staffs and several are greatly expanding investment in research capabilities in the areas of mix design, chemical additives, rheology of solid—liquid systems, modelling of processing and structures, test method development and studies of chemical mechanisms involved in corrosion, bonding, degradation by the atmosphere, and so on.
γH2AX foci induced by γ rays and 125IdU decay

Purpose: γH2AX foci formation was investigated after γ irradiation and after accumulating 125IdU decays to study the DNA double strand break (dsb) damage repair response in human breast cancer cells, MCF‐7.Materials and methods: Confocal laser scanning microscopy (CLSM) was used to detect γH2AX foci formed in response to DNA dsbs induced by 0, 0.5, 1, 2 and 5 Gy γ irradiation and 125IdU decays accumulated at −90°C in human breast cancer cells, MCF‐7. 125IdU treated cells were labeled with 4 different concentrations of 125IdU and then accumulated decays for 6, 19 or 35 days. γH2AX foci formation time for all experiments was 1 hour at 37°C. Visual confirmation of γH2AX foci was achieved by digital imaging (histogram analysis or profile analysis) and by standardizing the scored number of foci. The average numbers of γH2AX foci formed per cell after γ irradiation or accumulated 125IdU decays were determined by counting red voxels or counting γH2AX foci in propidium iodide (PI) counterstained nuclei by eye in ...
Dose reduction and lesion delectability in abdominal CT

The purpose of this study was to quantify how reducing x-ray beam intensity (i.e., mAs) affects lesion detection performance in abdominal CT examinations. A simulation package (Syngo Explorer) was used to reconstruct 4-mm thick CT images of a patient undergoing a standard abdominal exam. Simulations were performed at four x-ray beam intensities of 100%, 70%, 50%, and 25%. Four observers were used to perform a series of two Alternate Forced Choice (2-AFC) experiments that measure the lesion contrast (I 92% ) corresponding to a detection accuracy of 92%. Four lesion sizes were used ranging from 5 mm to 12 mm. Results were plotted as log(I 92% ) versus log(mAs) to quantify how changes in x-ray intensity affect lesion detection, as well as log(I 92% ) versus log(size) to generate contrast-detail curves. The fitted slope of noise in reconstructed images as a function of relative CT x-ray beam intensity was -0.25, which is about half the value of -0.5 expected for an ideal quantum noise limited imaging system. For lesion sizes between 5 mm and 10 mm, slopes of log(I92%) versus log(mAs) curves were very similar for all four observers, and ranged between -0.10 and -0.17. For 5 mm sized lesions, doubling the x-ray beam intensity improved detection performance by about 13%, whereas for 7 and 10 mm lesions, doubling the x-ray intensity improved detection performance by about 7%. For the 12 mm lesion there were no consistent patterns for all four readers, which may be related to the lack of a standardized viewing distance. The average slope for the four contrast detail curves was -0.41 ± 0.09, which is substantially less than the value of -1.0 predicted for an ideal observer operating with a quantum noise limited images. For our abdominal CT images, doubling of the lesion size resulted in improvements in lesion detection of ~ 30%.
Peer-based computer-supported knowledge refinement: an empirical investigation

Nonexpert peer-based knowledge refinement, it turns out, is just as helpful as expert-centric knowledge refinement for improving the quality of results.
Computer science by TV

Our use of television to teach the first computer science course for computer science majors is an attempt to make sure that the students get the right education. In our case it is not an attempt to enable one instructor to handle a large number of students but rather to handle small groups of students spread throughout the state.As a result of some shortage of computer science faculty, teaching beginners is often considered of lesser importance than other duties. For example, at one college in our state, an instructor with a little programming experience was hired to teach the beginners in computer science. This instructor felt he was well-enough equipped to handle the course. He covered the entire text and taught two languages, Fortran and PL/I. Our experience shows we can't cover two-thirds of that text, and then only in one language.Ours is the first computer science course which our majors take. It presumes no programming experience. It has two goals, to introduce the student to the fundamentals of computer science through a study of algorithms and programming, and to start the student well into PL/I. The course is taught as a one-semester four-credit course which meets five times per week.We made half-hour video tapes under excellent production conditions to cover the material of the course.
Determining Parameter Estimation Efficacy of the 3PL IRT Model in the Pediatric Behavioral Sciences Using Small Data Sets

Determining Parameter Estimation Efficacy of the 3PL IRT Model in the Pediatric Behavioral Sciences Using Small Data Sets
Modified LQG/LTR-based controller design for distributed parameter motion control systems

Abstract Robustness of controllers with finite dimensional state feedback for flexible manipulators is addressed by using colocated and noncolocated actuator and sensors. Sensor-actuator colocation guarantees that open-loop system transfer function is minimum phase. Noncolocation of sensor-actuator causes the open-loop system transfer function to become nonminimum phase. Standard linear quadratic gaussian/loop transfer recovery (LQG/LTR) design methodology requires that the open-loop system transfer function be minimum phase for loop transfer recover. However, the LQG/LTR methodology can still be applied for noncolocated actuator-sensor configurations, despite the lack of general proof of loop transfer recovery. Residual dynamics are considered as additive unstructured uncertainty in the design of the robust controller. Modified linear quadratic gaussian/loop transfer recovery (LQG/LTR) methodology is used to design the controller that will achieve the desired loop transfer characteristics when the controller is implemented with state feedback plus observer combination.
Small-angle x-ray scattering of graphite-ferric chloride intercalation compounds

Abstract Small-angle X-ray scattering (SAXS) data were collected for two samples of ferric chloride intercalated in pyrolytic graphite and a comparison specimen of pristine graphite. The work was done on the 10 m SAXS instrument at the National Center for Small-Angle Scattering Research, Oak Ridge, Tennessee, with the help of NCSASR staff member Dr. J.S. Lin. The experiment was run using Cu Kα radiation and a sample-to-detector distance of 2.2 m, so that the detector scanned an angular range of 3.4–37 mrad, representing momentum transfers, Q , of 0.014–0.15 A −1 . The samples were oriented with their planes normal to the beam axis, so the experiment was sensitive to inhomogeneities within the plane. The scattering patterns obtained were all roughly circular, indicating that the samples were isotropic. The two intercalated samples, C 14 FeCl 3 and C 21 FeCl 3 , had almost identical patterns, scattering much more strongly than the pristine graphite. The graphite displayed scattering maxima at Q values of 0.044, 0.088, 0.11 and 0.13 A −1 . These peaks were present in broadened form in the intercalated samples. Radii of gyration were estimated by extrapolating the slope of the scattering curve to Q = 0, giving 140 (C 14 FeCl 3 ), 145 (C 21 FeCl 3 ) and 214 A (graphite).
A Reassessment of the Burden of Eastern Europe on the USSR

Abstract A comprehensive accounting of the contributions and costs of East European satellite states to Soviet foreign and defence policy indicates that they were hardly ever a ‘burden’ to the USSR, even at their most costly in 1982, and therefore Gorbachev's decisions later in the decade to allow those regimes to distance themselves from Moscow must be interpreted as part of the Soviet leader's overall political strategy, not a result of material inability to maintain the status quo.
SURGICAL MANAGEMENT OF LOW-STAGE RENAL CELL CARCINOMA: TECHNOLOGY DOES NOT SUPERSEDE BIOLOGY

Abstract Objectives To address the concern that laparoscopic radical nephrectomy (LRN) is being applied in cases of small renal masses in which nephron-sparing surgery (NSS) might be more appropriate. Methods From 1998 to 2003, 381 consecutive patients underwent 391 procedures at our institution for renal cell carcinoma, of which 336 were for organ-confined tumors. The temporal trends in the application of LRN and NSS were assessed relative to the clinical stage. Results During the transition from early (1998 to 2000) to late (2001 to 2003) experience with laparoscopy, the use of LRN among patients with Stage T1a (4 cm or smaller) lesions remained infrequent (21% and 20%, respectively). In contrast, LRN increased among patients with larger lesions during this same interval (Stage T1b, 36% versus 56%, P = 0.017 and Stage T2, 24% versus 41%, P = 0.056). Concurrently, the use of NSS (open surgical or laparoscopic partial nephrectomy) increased for both Stage T1a (25% and 31% versus 34% and 37%, P = 0.082) and T1b (8% and 6% versus 19% and 5%, P = 0.017) tumors. Multivariate analysis demonstrated that the use of both NSS and LRN increased significantly with time ( P = 0.002 and P = 0.001, respectively). Neither NSS nor LRN were associated with a greater risk of perioperative complications relative to radical or open surgery ( P >0.05 for both). Conclusions During a 6-year period at our institution, most Stage T1a lesions were managed with NSS, and a significant increase occurred in the use of NSS for Stage T1b tumors, despite the concurrent increasing application of LRN. These findings suggest that oncologic, rather than technologic, concerns were determining our practice patterns.
Political Climate and Smoke-Free Laws in Rural Kentucky Communities:

The purpose was to determine factors associated with rural communities' political readiness to enact smoke-free laws. Data from baseline assessment of a longitudinal intervention study to promote smoke-free policy in rural Kentucky communities; key informants (n = 144) and elected officials (n = 83) from 29 counties participated in cross-sectional telephone interviews. Controlling for population size and county-level smoking rate, the following factors predicted elected officials' perception of the likelihood of a local smoke-free law passing in the next 12 months: (1) support from the local board of health; (2) support from local leaders; and (3) smoke-free hospitals. Communities with lower adult smoking prevalence were more ready for smoke-free laws. Rural health advocates can increase political readiness for smoke-free laws by educating and engaging Board of Health members and local leaders, promoting the voluntary adoption of smoke-free policies in rural hospitals, and investing in effective population-based approaches to evidence-based tobacco treatment in rural communities.
Admissibility of Scientific Evidence and Expert Testimony: One Potato, Two Potato, Daubert, Frye

The goal of scientific research is to increase our knowledge. As knowledge grows, previously well-accepted theories are cast off and replaced by new theories, which in time may be refined or rejected. Though the world was once believed to be flat, we believe it to be rather round today. Newton’s discovery of gravity still holds, so far.Expert testimony has been admitted in America since the 1600’s; for example, a Dr. Brown gave “scientific” testimony at a heresy trial that the defendant had “bewitched” several persons.’ How should trial judges filter which scientific and other expert evidence is admissible?
P-selectin and intercellular adhesion molecule-1 expression after focal brain ischemia and reperfusion.

Polymorphonuclear leukocytes have been implicated in the development of the "no-reflow" phenomenon after focal cerebral ischemia and reperfusion. To further understand the role of granulocytes in m...