cssi/SciSciGPT-SciSciNet huggingface dataset:
Establishing Performance Standards Using Common Assignments and Rubrics: Measurable and Achievable Student Learning Outcomes

The struggle for many community colleges is how to model and/or remodel what happens in the classroom into a plan to measure and achieve student learning outcomes (Syed & Mojock, 2008). Encountering the same struggle, the psychology department of El Centro College (ECC) of the Dallas County Community College District implemented a methodology for measuring and achieving student learning outcomes. The methodology included the following: (a) using common assignments across all classes; (b) an informational literacy component integrated into the curriculum; (c) establishing performance standards via a common rubric; (d) model submissions depicting high quality work; and (e) a rating system of exemplars. By using this methodology, student learning outcomes within a discipline were both measurable and achievable.
Laser Micro-Machining of Spherical and Elliptical 3-D Objects Using Hole Area Modulation Method

Laser micromachining has the capability to fabricate very small and basic 2.5-D geometric features on a range of materials in the form of laser ablation or irradiation. Short pulsed lasers that can achieve wide range of wavelengths in the form of harmonics of infrared laser beam at 1064 nm wavelength have been a very effective micro-machining tool used for hole drilling, cutting, scribing, trimming and marking. A review of laser processing of materials is given in this paper. Direct laser ablation can be performed by controlling laser beam properties such as laser energy, intensity, pulse duration and wavelength in micro-machining 3-D geometric features. However, this method requires additional capabilities for a typical laser beam generating and delivery system. When the laser beam properties cannot be altered, Hole Area Modulation (HAM) method becomes alternative solution by controlling the density of the holes and the step size in a mask to improve the accuracy of the 3-D geometric feature. In this paper, we perform modeling, planning and simulation of laser micromachining with hole area modulation method to produce spherical and elliptical objects 3-D geometrical features that are typical for aspheric and or refractive micro-lenses. A computational methodology is developed to design a mask with varying density and diameter of the holes. The masks are created using micro-drilling and utilized in laser micromachining of 3-D objects on polycarbonate polymer substrates.
Crystallization and structure determination of the core‐binding domain of bacteriophage lambda integrase

Bacteriophage lambda integrase catalyzes site-specific DNA recombination. A helical bundle domain in the enzyme, called the core-binding domain (IntCB), promotes the catalysis of an intermediate DNA-cleavage reaction that is critical for recombination and is not well folded in solution in the absence of DNA. To gain structural insights into the mechanism behind the accessory role of this domain in catalysis, an attempt was made to crystallize an IntCB–DNA complex, but crystals of free IntCB were fortuitously obtained. The three-dimensional structure of DNA-free IntCB was solved at 2.0 A resolution by molecular replacement using as the search model the previously available DNA-bound 2.8 A structure of the IntCB domain in a larger construct of lambda integrase. The crystal structure of DNA-free IntCB resembles the DNA-bound structure of IntCB, but exhibits subtle differences in the DNA-binding face and lacks electron density for ten residues in the C-terminus that form a portion of a linker connecting IntCB to the C-terminal catalytic domain of the enzyme. Thus, this work reveals the domain in the absence of DNA and allows comparison with the DNA-bound form of this catalytically activating domain.
Complete positivity of matrices of special form

Abstract Given that B,C 2 ,…,C k are positive semidefinite (PSD) n -by- n real matrices and B is entrywise nonnegative, we characterize (fully for n=2 and partially for n⩾3 ) when B may be written as B=∑ i=2 k B i so that B i and B i −C i are PSD and B i is entrywise nonnegative, i=2,…,k . These characterizations are used to give conditions under which an entrywise nonnegative, PSD matrix A with a special block form can be written as A=BB T , in which B is entrywise nonnegative.
H2S adsorption onto clean and oxygen covered iron films

Abstract Auger electron spectroscopy (AES) and the chemisorption-induced resistance change (CIRC) have been employed to compare the kinetics of low pressure H 2 S adsorption on clean and oxygen-covered Fe films. Although the oxygen overlayer does not appear to affect the saturation coverage of adsorbed H 2 S, it does significantly enhance the adsorption rate when compared with the clean Fe surface. Differences are also observed in the sulfur Auger spectrum obtained from the two surfaces. It is suggested that the differences observed in the adsorption rates and the shapes of the uptake curves result from a change in the rate-limiting adsorption step; from island growth for the clean Fe surface to molecular-precursor mediated adsorption on the oxygen-covered Fe surface. The adsorption of H 2 S did not lead to any obvious corrosion of the oxygen overlayer at the temperature of these measurements, about 295 K.
Laboratory Evidence for Surface Nucleation of Solid Polar Stratospheric Cloud Particles

Nitric acid-containing cloud particles, known as polar stratospheric clouds, play an important role in the springtime ozone destruction over the polar regions. Nitric acid initially condenses in the polar stratosphere to form supercooled solution droplets of mainly nitric acid and water with trace amounts of sulfuric acid. Nitric acid dihydrate (NAD) and nitric acid trihydrate (NAT) later crystallize from this supercooled solution phase to form solid polar stratospheric cloud particles. Until now, experimental data on this crystallization process has been analyzed under the assumption that NAD and NAT nucleation took place in the interior volume of a cloud droplet. However, in this paper, reanalysis of experimental data on the homogeneous freezing rates of concentrated aqueous nitric acid solution droplets provides substantial support for the occurrence of nucleation “pseudoheterogeneously” at the air -aqueous nitric acid solution interface of the droplet. Furthermore, in a following paper, theory that provides compelling evidence for such interfacial nucleation is developed. Together, the reanalysis of laboratory data in this paper and the supporting theoretical arguments in the following paper suggest that the homogeneous nucleation process occurring in atmospheric droplets may be a surface- rather than a volume-related rate process.
Testing predictions derived from inoculation theory and the effectiveness of self-disclosure communications strategies

Abstract We investigated the efficacy of self-disclosure as a strategy for reducing the effects of damaging information divulged by third-parties in business contexts. With both justified attacks and unjustified attacks emanating from news reporting organizations, consumer advocacy groups, and competitors, it is incumbent that organizations develop contingency plans for use in the communications environment. Two studies (using a combined sample of 390 university students) are described which tested several inoculation-related hypotheses. The efficacy of a refutational-same inoculation was demonstrated in Study I. Study II illustrated the superiority of a refutational-same defense over a forewarning-same defense, which demonstrates the need for situational specificity in the use of an inoculation strategy in a business context. These results provide evidence that the use of self-disclosure in business contexts should be confined to situations where (1) the specific negative information is known, (2) refutation of the specific points is possible, and (3) the threat of damage to beliefs is high.
NADPH‐diaphorase localization in the CNS and peripheral tissues of the predatory sea‐slug Pleurobranchaea californica

The distribution of putative nitric oxide synthase (NOS)-containing cells in the opisthobranch mollusc Pleurobranchaea californica was studied histochemically via NADPH-diaphorase (NADPH-d) reduction of Nitro Blue Tetrazolium (NTB). Whole mounts and cryostat sections were prepared from the central nervous system and peripheral organs, including the buccal muscles, esophagus, salivary glands, foot, mantle, and gills. NADPH-d-positive neurons were localized predominantly to the buccal and pedal ganglia as well as to distinct areas of the cerebropleural and visceral ganglia. A variety of identified neurons were positive for NADPH-diaphorase in various central ganglia, including the metacerebral cells of the cerebropleural ganglion, putative locomotor neurons of the pedal ganglia, and buccal motoneurons. Specific staining was observed only in somata of central neurons, whereas neuropil areas remained unstained. However, NADPH-d-reactive axons were dense in buccal ganglion nerves, whereas peripheral nerves and connectives of other ganglia had few or no NADPH-d positive terminals. In the periphery, NADPH-d activity was detected only in a few neurons of the rhinophore and tentacle ganglia. NADPH-d staining was marked in the salivary glands and gills, but there was no or very little staining in the esophagus, buccal mass, and foot. Histochemical stain production required the presence of both beta-NADPH and NBT; alpha-NADPH could not substitute for beta-NADPH. The inhibitor of NOS, 2,6-dichlorophenol-indophenol, at 10(-3) M, totally abolished NADPH-d-positive staining. The apparent high activity of central NADPH-d contrasts with much lower activity in the ganglia of the related gastropod Tritonia. These data suggest a role for nitric oxide as a signal molecule in the central nervous system of Pleurobranchaea.
Precise boundary element computation of protein transport properties: Diffusion tensors, specific volume, and hydration.

A precise boundary element method for the computation of hydrodynamic properties has been applied to the study of a large suite of 41 soluble proteins ranging from 6.5 to 377 kDa in molecular mass. A hydrodynamic model consisting of a rigid protein excluded volume, obtained from crystallographic coordinates, surrounded by a uniform hydration thickness has been found to yield properties in excellent agreement with experiment. The hydration thickness was determined to be δ = 1.1 ± 0.1 A. Using this value, standard deviations from experimental measurements are: 2% for the specific volume; 2% for the translational diffusion coefficient, and 6% for the rotational diffusion coefficient. These deviations are comparable to experimental errors in these properties. The precision of the boundary element method allows the unified description of all of these properties with a single hydration parameter, thus far not achieved with other methods. An approximate method for computing transport properties with a statistical precision of 1% or better (compared to 0.1–0.2% for the full computation) is also presented. We have also estimated the total amount of hydration water with a typical −9% deviation from experiment in the case of monomeric proteins. Both the water of hydration and the more precise translational diffusion data hint that some multimeric proteins may not have the same solution structure as that in the crystal because the deviations are systematic and larger than in the monomeric case. On the other hand, the data for monomeric proteins conclusively show that there is no difference in the protein structure going from the crystal into solution.
Search on surfaces: Exploring the potential of interactive tabletops for collaborative search tasks

Collaborative information seeking often takes place in co-located settings; such opportunities may be planned (business colleagues meeting in a conference room or students working together in a library) or spontaneous (family members gathered in their living room or friends meeting at a cafe). Surface computing technologies (i.e., interactive tabletops) hold great potential for enhancing collaborative information seeking activities. Such devices provide engaging direct manipulation interactions, facilitate awareness of collaborators' activities, and afford spatial organization of content. However, current tabletop technologies also present several challenges that creators of collaborative information seeking system must account for in their designs. In this article, we explore the design space for collaborative search systems on interactive tabletops, discussing the benefits and challenges of creating search applications for these devices. We discuss how features of our tabletop search prototypes TeamSearch, FourBySix Search, Cambiera, and WeSearch, illustrate different aspects of this design space.
Lennard-Jones-potential calculation of C60 stage-one graphite.

The potential energies per atom of pure graphite and of ${\mathrm{C}}_{60}$ stage-one graphite intercalation compound (GIC) are compared in a calculation based on summing pairwise a Lennard-Jones 12-6 potential between all mass points with parameters taken from previous calculations on pure graphite. The C atoms are treated as uniformly smeared onto rigid spheres and rigid planes. For graphite the potential has a minimum of -46 meV/atom at an interplanar spacing of 3.37 \AA{} with a compressibility of 3.0\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}12}$ ${\mathrm{cm}}^{2}$/dyn. For the GIC, assuming a triangular ${\mathrm{C}}_{60}$ net, the minimum is -22 meV/atom occurring at both a ${\mathrm{C}}_{60}$-graphene and a ${\mathrm{C}}_{60}$-${\mathrm{C}}_{60}$ nearest approach distance of 2.9 \AA{}. This distance is comparable to fcc ${\mathrm{C}}_{60}$ at room temperature. The calculated compressibility is 3.8\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}12}$ ${\mathrm{cm}}^{2}$/dyn.
Sensitivity analysis of pediment development through numerical simulation and selected geospatial query

Abstract Dozens of references recognizing pediment landforms in widely varying lithologic, climatic, and tectonic settings suggest a ubiquity in pediment forming processes on mountain piedmonts worldwide. Previous modeling work illustrates the development of a unique range in arid/semiarid piedmont slope ( − 3 m y − 1 restrict pediment development by fostering piedmont incision and/or wholesale removal (stripping) of regolith mantles prior to footslope pediment development. Simulations illustrate an insensitivity to alternating layers of sandstone and shale 3–15 m thick oriented in various geometric configurations (vertical, horizontal, and dip-slope) and generating different regolith hydrologic properties and exhibiting weathering rate variations up to 3-fold. Higher fluxes and residence times of subsurface groundwater in more humid environments, as well as dissolution-type weathering, lead to a thickening of regolith mantles on erosional piedmonts on the order of 10 1 m and an elimination of pediment morphology. An initial test of the model sensitivity analysis in arid/semiarid environments, for which field reconnaissance and detailed geomorphic mapping indicate the presence of pediments controlled by climatic conditions (soil hydrologic properties, vegetation characteristics, and bedrock weathering style) that are known and constant, supports our modeling results that pediments are more prevalent in hydrologically-open basins.
Phosphodiesterase inhibitor modulation of brain microvascular endothelial cell barrier properties

Abstract Background and purpose Brain microvascular disorders, including cerebral microscopic hemorrhage, have high prevalence but few treatment options. To develop new strategies for these disorders, we analyzed the effects of several phosphodiesterase (PDE) inhibitors on human brain microvascular endothelial cells (HBECs). Methods We modified barrier properties and response to histamine of HBECs using cilostazol (PDE3 inhibitor), rolipram (PDE4 inhibitor), and dipyridamole (non-specific PDE inhibitor). Results Cilostazol and dipyridamole altered the distribution of endothelial F-actin. Cilostazol increased expression of tight junction protein claudin-5 by 118% compared to control (p Conclusions These findings demonstrate distinctive effects of cilostazol and other PDE inhibitors on HBECs, including enhanced barrier characteristics and mitigation of response to histamine. PKA-mediated effects of cilostazol were prominent in this model. These in vitro findings are consistent with therapeutic potential of PDE inhibitors in human brain microvascular disorders.
The effects of long-term starvation and acclimation temperature on glucose regulation and nitrogen anabolism in the frog, Rana pipiens—I. Winter animals

Abstract 1. 1. Concentrations of serum glucose, serum amino acids and serum urea, as well as total excreted urea were measured in frogs, Rana pipiens —obtained in January and February—acclimated at 4, 20 and 25°C, during food deprivation lasting 25, 17 and 27 days, respectively. 2. 2. The concentration of glucose and amino acids in serum was maintained at 38·5, 38·2 and 44·5 mg%, and 30·0, 39·8 and 27·4 mM, respectively in frogs acclimated at 4, 20 and 25°C, respectively. 3. 3. The concentration of urea in serum was maintained at a constant level of 3·67 and 3·76 mM in 20 and 25°C acclimated frogs. Frogs acclimated at 4°C had variable to zero quantities of urea in their serum. 4. 4. The rates of urea excretion were determined and observed to be maintained at a constancy of 192·8 and 222·6 mμmoles/g per hr in 20 and 25°C accilimated frogs, but at a variable but decreasing rate in 4°C acclimated frogs. 5. 5. Regulation of the concentration of glucose and amino acids in serum was discussed with respect to hormonal influence upon standard metabolism. 6. 6. The advantages of a metabolic dependence upon glycogen rather than triglycerides in hibernating R. pipiens was discussed. 7. 7. Based on these observations, it is suggested that glucose derived from glycogen is the primary mobilizable metabolite in winter frogs.
The constrained equilibrium theory: Sulphide phases in meteorites

Abstract The constraints imposed by nucleation kinetics are taken into account in calculations of the condensation of sulfide phases from a gas of solar composition. Troilite will condense from a gas supersaturated with respect to metallic iron at temperatures which are much higher than from a gas at equilibrium with iron. In a solar gas at relatively high pressures, where we postulate that the precursors of the enstatite chondrites form, liquid troilite is condensed. At lower pressures of a solar gas, where we postulate that the precursors of the ordinary chondrites form, solid troilite is condensed. The solid does nob accommodate significant amounts of some sulfides in solid solution at activities less than unity and some chalcophilic elements will not tend to co-condense. On the other hand, liquid troilite can accommodate significant concentrations of sulfides in solution at activities less than unity and other chalcophile elements will co-condense. The apparently anomalous differences in the content of some chalcophile elements which have been observed between the enstatite and ordinary chondrites and the occurrence of oldhamite and niningerite are consistent with our calculations. Some implications and predictions concerning the genesis of sulfide and metal phases which result from our calculations will be discussed.
Gas solubility in glassy polymers—a correlation with excess enthalpy

Abstract Solubility coefficients for CO 2 , Ar and CH 4 in polystyrene (PS) films with glass transition temperatures ( T g ) of 52 to 107°C were measured in a pressure-decay sorption apparatus at 1 atm over a temperature range of 20 to 90°C. The gas solubility at 30°C increased as the T g of the PS increased; the heat of solution was largest for the PS with the highest T g . This observed dependence of gas solubility on T g was analysed in terms of enthalpy-temperature relationships for glassy polymers. The solubilities for PS samples with different glass transition temperatures converged when comparisons were made on the basis of states of equal enthalpy instead of the temperature of measurement.
Quasi-random algorithms for real-time spacecraft motion planning and coordination

Abstract In this paper we address the problem of planning in real time the motion of one or more spacecraft, in the presence of a variety of constraints, including collision avoidance with static obstacles or other maneuvering spacecraft, and plume impingement avoidance. Such problems are very challenging from the computational point of view, and push the limits of currently-available planning algorithms, based on randomization, which provide computational tractability by relaxing the completeness requirement to probabilistic completeness. In this paper we apply to the spacecraft maneuvering problem a set of recently-developed quasi-random algorithms, which, combiding optimal orbital maneuvers and deterministic sampling strategies, are able to provide extremely fast and efficient planners. Moreover, the proposed algorithms are able to guarantee the safety of the space system, that is, the satisfaction of collision and plume impingement avoidance constraints, even in the face of finite computation times (i.e., when the planner has to be pre-empted). Examples of orbital maneuvering close to large structures will illustrate the effectiveness of the methods, and a discussion of the results will conclude the paper.
Cavitation in Metastatic Pulmonary Neoplasm

SUMMARY 1. A case of cavitation in a metastatic pulmonary neoplasm has been described. 2. Metastatic disease should be considered in the differential diagnosis of pulmonary cavitation.
Current concepts for relining complete dentures: a survey.

Abstract Reline procedures for complete dentures have received scant attention in the literature. Fifty-seven dental colleges responded to an 11-item survey on reline procedures. According to the tabulated data , most dental schools recommended the following (not necessarily our recommendations). 1. Leave the denture(s) out of the mouth for at least 24 hours prior to fabrication of the reline impressions. 2. Use tissue-conditioning material only on selected patients. 3. Use Coe Comfort as the tissue-conditioning material of choice. 4. Place either none or one relief hole in the maxillary denture, and place no relief holes in the mandibular denture prior to the impression(s). 5. Place relief holes along the palatal midline of the maxillary denture. 6. No specific size is recommended for the palatal relief holes. 7. Place 1 mm of basal surface relief and 1 to 2 mm of border relief before the reline impression is made. 8. Use a polysulfide rubber base material as the material of choice for reline impressions. 9. Use a closed mouth impression technique. 10. Remove the palate from the maxillary denture prior to processing. 11. Use heat-cured resin (Lucitone) for processing. 12. Use pressure-indicator paste prior to delivery of the denture(s). 13. Remount the complete denture(s) on an articulator after processing for making occlusal corrections.
Public Infrastructure, Private Input Demand, and Economic Performance in New England Manufacturing

Much of the current debate on the economic performance impacts of public infrastructure investment relates to the input-specific effects of such investment. In this article we explore these impacts by evaluating substitution patterns affecting private input use in New England manufacturing. Using a cost-based methodology, we find that, in the short run, public capital expenditures provide cost-saving benefits that exceed the associated investment costs due to substitutability between public capital and private inputs. Over time, however, stimulating investment in private capital increases economic performance more effectively than public capital expenditures alone and in fact reduces the cost incentive for such expenditures. In addition, growth in output motivated by infrastructure investment increases employment opportunities because this growth overrides short-run substitutability.
A Comparative Anatomy of Urban Social Conflict

This study explores local government's roles in "culture wars"—i.e., morals-based controversies such as those involving abortion clinic protest, anti-pornography crusades, debates over the extensio...
Comparison of visual and auditory perceptual functions of brain-injured and normal children.

Visual and auditory masking tests and perceptual-motor tests were administered to 39 brain-injured, non-defective children, aged 6 to 12, and to a comparison group of intact children of the same age. The masking tests in both modalities followed a rough continuum of meaningfulness (and therefore of presumed level of distraction) of the mask. Analysis was done of inter-modal and intra-modal scores, within and between the experimental and comparison groups. Results showed that the brain-injured group had less differentiated functioning in the auditory modality, as compared with the intact group and with its own visual functioning. Results are interpreted in terms of differences between audition and vision. The susceptibility of auditory functioning to attentional disorders is also discussed.
RNAi as a gene therapy approach

RNA duplexes of 21 - 23 nucleotides (nts), with approximately 2 nt 3' overhangs (called small interfering RNAs or siRNAs), have recently been shown to mediate sequence-specific inhibition of gene expression in mammalian cells via a post-transcriptional gene silencing (PTGS) mechanism termed RNA interference (RNAi). RNAi has been rapidly adopted as a functional genomics tool in a wide range of species, has been adapted to allow for the transient or stable knockdown of gene expression generation in cell lines and animals, and has been developed for high-throughput analysis of gene function in Caenorhabditis elegans. With an increasing list of genes successfully knocked-down by RNAi in mammalian cells and improvements in the delivery of siRNAs to cells, including in vivo delivery to mice, attention is now turning to assessing the potential RNAi has as a gene therapy approach. RNAi is likely to have the greatest impact as a therapeutic tool in two key clinical areas, cancer and infectious disease, but it also has the potential as a therapy for other disorders including some dominant genetic diseases. This review will describe the status of the science behind this novel mechanism and will illustrate the therapeutic potential of RNAi-based technologies, using examples from these critical clinical research areas.
An approach to free-responding on schedules that prescribe reinforcement probability as a function of interresponse time

Abstract A model is proposed for free-responding on schedules that positively reinforce an interresponse time of duration t with a probability u ( t ) that does not depend on the experimental history of the subject prior to the previous response. The organism is characterized at any point in time by its interresponse time distribution, and the learning process takes the form of a sequence of linear transformations on this distribution. The transformation corresponding to nonreinforcement increases the probability of long interresponse times. The transformation associated with reinforcement of an interresponse time t leads to two effects: an increase in the probability of short interresponse times, and an increase in the probability of interresponse times of duration approximately t . Expressions are derived for the asymptotic interresponse time distribution I ( t ). Predictions of the model are compared with data from random-ratio, variable-interval, and a certain DRL-like schedule.
Progenitor cell proliferation outside the ventricular and subventricular zones during human brain development.

The ventricular zone (VZ) and subventricular zone (SVZ) of the fetal brain are generally believed to give rise to all the neurons and glia that will populate the cerebral hemispheres. In rodents a mitotically active cell (progenitor cell) has been identified outside the VZ and SVZ, in the intermediate zone (IZ) of the cerebral hemisphere. The cell types that arise from these progenitor cells remain uncertain. We have set out to determine if a similar population of mitotically active cells is present in the IZ during human brain development, and to try and define the cell types that arise from this progenitor cell. Using a monoclonal antibody that recognizes proliferating cell nuclear antigen (PCNA), a replication-specific protein, the cerebral hemispheres from 9 human fetal and infant brains between ages of 15 and 38 weeks gestation were studied. PCNA-immunopositive cells were found in the internal capsule and cerebral white matter with approximately equal frequency and rarely in the cerebral cortex between 15 and 20 weeks gestation. In the internal capsule, the number of positive cells decreased by the end of the second trimester ; however, a relatively constant number of PCNA-positive cells remained in the cerebral white matter. By the last trimester relatively little staining was found in any of the regions studied. Anti-GFAP immunostaining indicated that at least some of these progenitors were in the glial lineage. These data provide direct evidence that, in addition to ventricular zone proliferation, a population of progenitor cells continue to proliferate within nascent white matter tracts during development.
Simplified microstrip patch antenna design for reduced surface wave applications

In this paper, we present a circular microstrip patch antenna design with a single shorting pin for reduced surface waves applications. The modal equation for the normalized resonance frequency of the pin-loaded patch is solved numerically. Simulation results show the capability of such antenna to reduce surface wave and lateral wave excitations. Comparison between the proposed design and an alternative one is carried out in this work. The simplicity of the design makes it a promising candidate for many applications, including large patch antenna arrays with reduced mutual coupling and global positioning system antennas with reduced susceptibility to low-angle interference.
High temperature brittle intergranular cracking in high strength nickel alloys undoped and doped with S, Zr, and/or B—II. Solute segregation analysis

Abstract In order to clarify the mechanism of high temperature brittle intergranular cracking in high strength nickel alloys, solute segregation at grain boundaries and on high temperature fracture surfaces has been examined by scanning Auger microscopy. Intergranular S segregation producing global embrittling effects was found to increase in the following order: alloys with low S or high S and Zr, high S and B, and high S. The grain boundaries extensively contained Ti or Zr rich sulfides in the S-doped alloys and B segregation inducing intergranular toughening in the alloy with high S and B. The alloys with low S, and high S and B showed more strongly S segregation on high temperature fracture surfaces, which was much greater compared with at grain boundaries, than with high S, and high S and Zr. The local stress intensification did not produce a remarkable S enrichment at grain boundaries except near sulfides. It is proposed that S fluxes from crack surfaces and stressed sulfides to the crack tip induce local embrittlement. The composition and temperature effects on the brittle cracking behavior are discussed in terms of the global and local embrittling effects.
A Major Peritoneal Reservoir of Precursors for Intestinal IgA Plasma Cells

Studies presented examine the origin of IgA plasma cells in B lineage chimeric mice constructed by reconstituting lethally irradiated mice with a mixture of syngeneic bone marrow cells and peritoneal cells from Ig heavy chain allotype congenic donors. In these mice, essentially all B cells in spleen and Peyer's patches are derived from the bone marrow donor; however Ly-1 B lineage cells which have been mainly detected in the peritoneum are derived from the peritoneal cell donor. Surprisingly, roughly half of the IgA plasma cells in the lamina propria of the gut are also derived from the peritoneal cell donor, suggesting an important role for peritoneally-derived B cells in the mucosal immune response.
A new tetrahedral tesselation scheme for isosurface generation

Abstract The marching cubes algorithm is widely used to generate isosurfaces from a 3D scalar field. A major problem associated with it is the possibility of mismatch between adjacent surface elements, leading to holes on the surface. In this work, we propose using a tetrahedral tesselation of space which would eliminate this problem. Comparing with existing remedies of the marching cubes method which subdivide each cube into tetrahedra, the current tesselation is more regular and symmetric.
Experimental studies relating to microfracture in sandstone

Abstract A fundamental understanding of the relation between stress concentrations at grain contacts and microfractures in granular aggregates is obtained through two-dimensional photomechanical model studies and is tested through observational studies of experimentally deformed sandstone discs, glass beads, and quartz sand. In uncemented aggregates, the state of stress in each grain is controlled by the manner in which the applied load is transmitted across grain contacts. The angles between lines connecting pairs of contacts and the axis of the principal load acting at the boundaries of the aggregate determine which of all contacts will be most highly stressed or “critical”. Microfractures follow that maximum principal stress trajectory which connects critical contacts, and they propagate through those points where the magnitude of the local maximum stress difference is the greatest. Microfractures, therefore, are extension fractures. It then follows that both the locations and orientations of fractures can be predicted if the state of stress in the grains is known. Positioning of critical contacts depends primarily on sorting, packing, grain shapes, and the boundary load conditions applied to the aggregate. Some critical contacts and, therefore, microfractures tend to join together in a series or “chain”. Orientations of chains are most strongly influenced by the direction of the maximum compressive load at the boundary of the aggregate. A hydrostatic load applied on the boundaries of an aggregate can cause microfracturing within grains. Orientations for microfractures and contact lines are random in poorly sorted aggregates, but they are influenced by packing in well sorted aggregates. Grains of cemented aggregates are more highly stressed at their centers than at contacts. By analogy, microfracture orientations depend strongly on the position of the greatest load axis and only slightly on the low-magnitude stress concentrations at contacts. These microfractures parallel the greatest principal stress trajectory in regions where the magnitude of the maximum stress difference is greatest. These observations lead to the conclusion that fractures in grains of cemented aggregates are also extension fractures and should exhibit a higher degree of preferred orientation than in uncemented counterparts. These conclusions hold when cementing materials have about the same elastic moduli as the grains. Cements may be so weak that the aggregate behaves as if it were uncemented in terms of microfracture fabric, or so stiff that the major part of the load is transmitted by the cement, and the composite is no longer an aggregate in the mechanical sense.
A general model and convergence results for determining vehicle utilization in emergency systems

Emergency Medical Service (EMS) systems can be modeled as spatially distributed queueing systems. Each location in the area has a preference ordering for the servers (usually based on proximity of calls to servers). When a call arrives, the dispatcher scans the preference list and assigns the most preferred idle vehicle to the call. If all vehicles are busy, the call is sent to a private ambulance system that operates in parallel to the EMS system. A major problem in designing and operating EMS systems is to estimate vehicle utilizations and busy probabilities for a given set of base locations. In earlier work, various systems of nonlinear equations have been proposed to estimate the vehicle utilization in EMS systems. In this paper we present a general model structure that encompasses much of the past work. We develop convergence conditions for the general model and show that a simple bisection method can be used to find solutions. The bisection method also leads to a test for the uniqueness of the solut...
Presence of life-shortening factors in spleens of aged mice of long lifespan and extension of life expectancy by splenectomy.

Abstract Spleen cells of aged (C57BL/6 × C3H)F 1 mice, when transferred into middle-aged mice of the same strain, severely reduced the survival of the recipients. This life-shortening effect became progressively greater with increasing age of the donor mice. In contrast, splenectomy of mice of interjacent ages sustained life; under our experimental conditions it nearly doubled the remaining life expectancy. Although the influence of the spleen on survival remains to be explained, the action of the age-related spleen factors on progenitor cells may cause the steady decline in immunologic capacity with advancing age (previously reported).
The national exposure research laboratory's consolidated human activity database.

EPA's National Exposure Research Laboratory (NERL) has combined data from 12 U.S. studies related to human activities into one comprehensive data system that can be accessed via the Internet. The data system is called the Consolidated Human Activity Database (CHAD) and is available at E-mail: http://www.epa.gov/nerl/ . CHAD contains 22,968 person days of activity and is designed to assist exposure assessors and modelers in constructing population “cohorts” of people with specified characteristics that are suitable for subsequent analysis or modeling. This paper describes the studies comprising CHAD and the various intellectual foundations that underlay the gathering of human activity pattern data. Next, it provides a brief overview of the Internet version of CHAD, and discusses how the program was formulated. Emphasis is placed on how activity-specific energy expenditure estimates were developed. Finally, the paper recommends steps that should be taken to improve the collection of activity data that would improve energy expenditure estimates and related information needed for physiologically based exposure–dose modeling efforts.
Pressure transient analysis in a reservoir with a compressible or impermeable circular subregion: gas cap or EOR-induced

A practical pressure transient analysis method is presented for the analysis of a drawdown test in a well near a circular subregion. Such subregions may exist naturally as gas caps or may be artificially produced by EOR operations. These subregions may be treated as either constant pressure or impermeable inner boundaries. The problem is mathematically posed and solved using the Laplace Transformation. A new semilog-type curve method is presented which may be used to determine the size of the circular subregion and the distance to it. The method is of particular importance in that it permits the estimation of the size of an EOR affected region without shutting in the injection well. 10 references.
Seeing the Insane in Textbooks of Abnormal Psychology: The Uses of Art in Histories of Mental Illness

Pictures in historical chapters of textbooks convey information about the values and assumptions of the authors’professions and the larger culture. We scrutinized 15 recent abnormal psychology textbooks for reproductions of art created before 1900. Thirteen works appeared in three (20%) or more textbooks. Overall, these pictures support a “Whiggish” account of history that celebrates the present and gives a distorted, incomplete rendering of the past. The 13 pictures tended to depict the mentally ill as an underclass who are released from their literal and metaphorical shackles by men who are “ahead of their time” in their struggles against prevailing ignorance. The pictures also emphasized the difference of the mentally ill by presenting a catalogue of stereotypic visual elements attributed to insanity throughout Western history. We argue for the inclusion in textbooks of “history for the sake of the past” as a way of genuinely engaging different ideologies and thereby stimulating interest in our own implicit values and biases.
Structural and Thermodynamic Variation in Nickel Aluminate Spinel

New structural and calorimetric data for samples of NiAl2O4 quenched from 600° to 1560°C are presented The spinel remains stoichiometric for all heat treatments. Based on the refinement of X-ray powder patterns, it is shown that the degree of disorder, defined as the mole fraction of tetrahedral sites occupied by Al3+, changes from x = 0.82 at 600°C to 0.78 at 1560°C. Simultaneously, the lattice parameter and enthalpy vary in a complex manner with quench temperature. The largest lattice parameter (0.80500 ± 0.00004 nm) and most exothermic enthalpy of annealing (heat released when sample is equilibrated at 780°C; -10.1 kJ/mol) occur for the sample quenched from 1100°C. A linear correlation exists between the heat of annealing and the lattice parameter. The results have been interpreted as a superposition of at least two effects: (1) the disordering of Ni2+ and Al3+ ions between octahedral (16d) and tetrahedral (8a) sites and (2) a second process, which may be a small amount of the disordering of ions into the usually empty (16c) sites.
Role of magnetic resonance enterography in the management of Crohn disease.

Objective To assess the impact of magnetic resonance enterography (MRE) on therapeutic decision making for patients with Crohn disease. Design Retrospective study. Setting Tertiary care medical center. Patient One hundred twenty patients who had either a history of or high suspicion for Crohn disease with onset of new symptoms underwent MRE over 18 months at our institution. All patients with Crohn disease were classified according to the Montreal system. Interventions Magnetic resonance enterography and medical vs surgical therapy. Main Outcome Measure Changes in management after MRE findings. Results Magnetic resonance enterography demonstrated active Crohn disease in 57.5% of patients, chronic changes of Crohn disease without active inflammation (eg, stricture, fistula, or abscess) in 12.5% of cases, and no evidence of Crohn disease in 30% of cases. After MRE, 37 (31%) had no change in medical therapy, 64 (53%) had additional medical management for active inflammation, and 19 (16%) underwent an operation for complicated Crohn disease or medical intractability. In all surgical patients, the intraoperative findings were consistent with the MRE diagnosis. The mean (SD) MRE score was 1.6 (0.5) for patients who had no change in their treatment plans, 5.8 (1) for patients who underwent surgery, and 8 (0.4) for patients who had their drug regimen changed (P Conclusions Magnetic resonance enterography shows promising ability to characterize the presence of active Crohn disease as well as chronic complications (eg, differentiate between stricture due to edema vs fibrotic scarring). Magnetic resonance enterography is fast becoming a useful adjunct in the management algorithm of patients with Crohn disease.
On Petri nets and self-stabilization of communication protocols

With Petri nets as the concurrent model, the issue of self-stabilizing communication protocols is discussed. It is argued that self-stabilizing extensions of communication protocols should not interfere with their normal operations by giving a new definition of self-stabilizing extension and a ring net that meets the new definition. It is also argued that communication protocols are usually delay sensitive and timed Petri nets provide a more suitable formal model than ordinary Petri nets to express the self-stabilizing property. The possibility and suitability of using Petri nets with a new type of transitions, the max transitions, to express self-stabilizing communication protocols is explored. To facilitate practical implementations, two types of interferences, external and internal interferences, are formally identified and discussed. >
Role of Ferrites in Negative Index Metamaterials

The periodic composite structures consisting of magneto-dielectric constituents as well as metallic wires, flakes leads to determine a particular configuration which may lead to electrical and/or magnetic properties which naturally cannot be obtained from single constituents. It was shown that the periodic wires structure led to negative effective permittivity.Furthermore, split ring resonators (SRR) gave rise to a negative permeability. The negative index may be obtained by having both wires and ferrites in a meta-material ferrite structure. Such a structure is vastly more practical in shape and size than the wire-SRR construct. We assume a TEM mode of propagation such that is parallel to the wire axis and is perpendicular to the wire. The magnetization of the ferrite, M, is also along the wire direction. We represent the wire element as a lumped element. The region between the wires is treated as a continuous ferrite medium. From the determination of the 4 elements of the transfer matrix, the scattering S-parameters may be easily calculated. The effective refractive index and impedance may now be calculated in terms of S11 and S21.
Special cylindrical free surface jets of liquid crystalline polymers and their stability

We examine two special solution families of the governing equations for free surface, axisymmetric, cylindrical liquid crystalline polymer (LCP) jet flows, in which only the uniaxial orientation pattern is accommodated. From these ideal transient solutions, we analyze the linearized stability of the coupled flow and microstructure in the LCP slender jet approximation. Our analysis reveals a window of uniaxial order parameters for both jets in which the LCP microstructure yields a negative first normal stress difference that may completely stabilize the jets provided the negative first normal stress difference dominates the isotropic surface tension and viscous stress during some period of time. It is shown that the negative first normal stress difference in the stable jets is the result of the low degree of orientation in the microstructural material.
The Later Habsburg Concept of Statecraft

The historian of the seventeenth century who bewails the absence of a creditable biography of Louis XIV or of William III underlines a significant development of historical writing in the twentieth century. Overpowered by those who deny that biography can be history and convinced that the masses have never secured their due share of attention in early modern times, the scholar uneasily plots an investigation of underground discontent in the gilds of Colbert's day or resolutely pens an essay that destroys once and for all the idea that the workers of France admired Napoleon. Meanwhile, in classes which race from Petrarch to Waterloo, the scholar turned teacher admits that there actually were an age of absolutism and an age of enlightened despotism, for the royal touch is inescapable.
What do commissars do

Abstract The note considers the possible interaction between the narrowing of wage differentials in China and the degree of hierarchy-cum-supervision at the plant level in the Chinese economy. It is argued that the Chinese regime may end up with greater hierarchy in its techniques of production, paradoxically, as a result of the narrowing of wage differentials. In developing this thesis, the note raises an issue of novelty in the theory of comparative economic systems.