cssi/SciSciGPT-SciSciNet huggingface dataset:
Design Guidelines for Solid-Catalyzed Reactive Distillation Systems

In this paper we discuss design guidelines for solid-catalyzed reactive distillation systems. The guidelines are used to generate initial estimates for column pressure, reactive zone location, catalyst mass, reactant feed location, reactant ratio, reflux ratio, column diameter, number of equilibrium stages, and packed height. They form a part of a methodical design procedure that makes extensive use of both nonequilibrium (rate-based) and equilibrium-stage simulation models. Important choices prior to design include selection of reliable thermodynamic and reaction kinetic models. We tested the guidelines for two etherification systems and validated them experimentally for a hydration reaction. The results from a case study, the manufacture of tert-amyl methyl ether, are shown here. Superimposing reaction on separation leads to unique design trade-offs. Thus, column diameter depends both on maximum vapor velocity and on packing catalyst density, reactant ratios are a function of conversion and azeotrope fo...
Consumer perceptions of generic products: a Mexican study

Previous research studies on generic products focus mainly on mature markets such as the USA. These studies measure consumer perceptions of all generic products as a whole, with respect to price and quality. With the passing of the NAFTA, retailers’ interest in the relatively young Mexican market has increased. The purpose of this study is to determine Mexican consumers’ overall perceptions of generic grocery products, to examine if there are any differences in perception across demographic groups and to determine if there are differences in the perception of generic products across product categories. Two variables were examined: risk perception of generic products and satisfaction with generic products.
Prospects for destructive self-induced interactions in a vortex pair

The vortex wakes of large transport aircraft can pose a hazard to smaller following aircraft in the vicinity of airports during landing and takeoff operations if certain separation guidelines are not observed. In order to reduce the hazard potential, and thereby the separation distances, efforts are being made to find more rapid wake-dissipation mechanisms. In this paper, numerical simulations are made of the three-dimensional timedependent instabilities that might be initiated in a vortex pair by sinusoidal displacements of the filaments. The objective of the study is to find those displacements and phase angles that produce the most rapid destruction of the vortices. It is concluded that, of the wave patterns tried on the one pair of wake filaments, the only instability mode that leads to destructive interactions of the vortices is the Scorer-Crow process.
Optimal space-time fuel distribution in a 1-D numerical core model

Abstract Numerical solutions to the space-time minimum fuel loading problem for the LWR are developed using a 1-D variational nodal method to describe the core and an approximate nonlinear programming technique to solve the optimization problem. The resulting power shape agrees with the analytic optimum solution to the 1-D homogeneous core problem for only a limited set of constraining conditions. In general, reducing the maximum power peaking or the number of fuel regions in the numerical problem, changes the optimum power shape from the center-peaked predicted analytically to an outerpeaked, inner-depressed power shape. The time-dependent problem is then addressed using the same core model and optimization algorithm with the objective of minimum fuel poison control. The core is depleted from the optimum final state to an initial state determined by the maximum permissible control. The numerical solutions are then used to formulate a consistent theory of LWR fuel management for minimum core fuel loading.
Involvement of the mandibular canal: Early sign of osteogenic sarcoma of the mandible

A case of osteogenic sarcoma of the mandible is presented. The most striking radiologic finding in this case was irregular widening of the mandibular canal, with areas of narrowing and loss of fine parallel cortical margins of the walls of the canal. These changes were accompanied by widening of the periodontal membrane of the adjoining teeth, an early sign of osteogenic sarcoma described by Garrington and colleagues, and loss of lamina dura of the same teeth and one additional adjacent tooth.
Thymlne glycol lesions terminate chain elongation by DNA polymerase I in vitro

Abstract Single-strand circular DNA from bacteriophage M13mp9 was chemically modified with osmium tetroxide to introduce specifically cis-thymine glycol lesions, a major type of DNA damage produced by ionizing radiation. An oligonucleotide primer was extended on damaged and undamaged templates using either the large fragment of E. coli pol I or T4 DNA polymerase. The reaction products were analysed by electrophoresis alongside a DNA sequence ladder. Synthesis on the damaged templates terminated at positions opposite thymine bases in the template. These results indicate that cis-thymine glycol lesions in single-strand DNA constitute blocks to synthesis by DNA polymerases in vitro. Surprisingly, replication halts after the correct nucleotide, dAMP, is inserted opposite the lesion. These results imply that the primary effect of the thymine glycol lesion is suppression of DNA synthesis and that the lesion is not a potent mutagen.
Entropy Growth Is the Manifestation of Spontaneity

Every student of thermodynamics grasps entropy growth in terms of dissipation of energy. The real nature of energy and entropy is subtle. This critical review of the evolution of thermodynamic thought uncovers the remarkable advance on our understanding of energy made by Kelvin with his dissipation of energy proposition. Maxwell and Planck, however, pointed out that dissipation of energy does not exhaust growth of entropy (i.e., the idea of spontaneity), and in fact, as it is shown here, Kelvin’s proposition of dissipation of energy (1852) is subsumed under the principle of the increase of entropy (Clausius, 1865). It is necessary, therefore, for thermodynamics to become a coherent conceptual system, to introduce spontaneity as an independent concept. Instead of the heat-work dyad framework, the introduction of spontaneity entails energy transformation to be viewed in terms of a triad framework of heat (from the reservoir)-work-spontaneity. Spontaneity is the new energy in the triad framework, and it is also clear that energy commodity (fungible energy or energy carriers) is only one kind of spontaneity, stock spontaneity; the other kind is ongoing spontaneity, the consideration of which is necessary for comprehending problems of homeostasis in both the organic and inorganic worlds.
A model of growth by hetero-coagulation in seeded colloidal dispersions

Abstract A mathematical model for growth by hetero-coagulation in seeded colloidal dispersions incorporating electrostatic interactions, dispersion forces, and Brownian diffusion has been developed. Electrostatic effects are incorporated via an accurate numerical solution of the linearized Poisson—Boltzmann equation for the potential around two unequal spheres. Stokes—Einstein Brownian diffusivities have been calculated using exact mobility results for the two-sphere geometry. Our analysis of the complete model reveals that simpler theories based on neglect of hydrodynamic interactions are valid over a wide range of conditions encountered in hetero-coagulation. Scaling laws and “contour maps” are presented for growth rates as a function of the ratio of particle/seed diameters and of the ratio of particle size to double layer thickness. An analysis for the evolution of polydispersity is presented and it is shown that conditions in seeded systems usually favor a monodisperse size distribution.
Quantifying and comparing the value of non-timber forest products in the Amazon

Abstract The use of sustainable harvest practices in the tropics is often proposed as a way to maintain the environment and address the poverty issues that dominate many tropical regions of the world. In theory, the adoption of these methods can provide win–win solutions to tropical deforestation because they address the environmental consequences of deforestation while increasing the welfare of forest inhabitants. However, there is little reliable data that can be used to test this hypothesis since many of the goods produced in sustainable systems do not have well-defined markets and are most often consumed at home. This paper examines the benefits of collecting and harvesting non-timber forest products in the tropics through various methods using household panel data collected in 1996 and 2000 in the Ouro Preto do Oeste region of Rondonia, Brazil. We estimate the use-value of land under forest, agriculture, and pasture and complement these estimations with census data and regression analysis. Our estimations reveal that households utilizing sustainable practices in the forms of agroforestry and the collection of non-timber forest products have significantly higher levels of diversification. We conclude that directing policy towards “win–win” strategies may not be desirable for reducing both poverty and deforestation in this region since we find no clear evidence that these can successfully be addressed simultaneously. Sustainable development policy should focus on increasing the value of the forest, or reducing the opportunity cost of leaving standing forest on the household lot, if sustainable production strategies are to be more attractive to households in the future.
The conditional entropy in the microcanonical ensemble: The quantum lattice

Abstract The existence of the conditional entropy in the thermodynamic limit for a class of long range compatible observables operating on a quantum lattice is exhibited for the microcanonical ensemble. This limit is demonstrated first along a special sequence of cubes with a fixed contraction parameter. Properties of the parameter dependent limit are utilized to remove the parameter, and the results are extended to van Hove sequences approximable by cubes.
A proposed model of cancer as the inappropriate expression of non-body introns

Abstract An a posteriori proposal is made that cancer represents an alien non-body phenotype erupting from “silent” gene groups within actively coding regions of a normal cell's genome. Relevant empirical data is garnered from the literature and twelve premises are derived from the data. On the basis of these premises it is hypothesized that the malignant neoplastic phenotype results from interference with non-histone chromosomal proteins causing retention and expression in a body cell of non-body introns. These are asserted to be the same introns which, as exons in a trophoblast cell, direct the normal development of the fetal placenta. Development of a malignant tumor is presented as a pathological recapitulation of the development of a normal placenta. Unrestrained tumor growth is attributed to the inability of endogenous body chalones to suppress the non-body gene groups coding for neoplastic mitosis, while invasion and metastasis result from failure of the non-body genes which code for implantation and mitosis to switch off at the proper time. The hypothesis asserts that all carcinogenic agents alter phosphorylation of non-histone chromosomal proteins, that cancer and normal trophoblast cells are genetically programmed to travel through the body's vascular system to effect immunosuppression in lymphoid tissues, that malignant neoplastic tissue will regress when exposed to trophoblast-based chalones, and that mammals immunized against trophoblast-based antigen will be resistant to the development of malignant tumors.
Empirical similarity of responses of two random samples of North Carolina swine producers to a management questionnaire used in the US National Swine Survey

Abstract The United States Department of Agriculture's (USDA) National Animal Health Monitoring System (NAHMS) National Swine Survey (NSS), implemented in 1990, represents the first national effort to collect on-farm data using a statistically valid method. The purpose of the North Carolina Swine Survey (NCSS) was to evaluate the reliability of the NSS by assessing the similarity of responses between the North Carolina portion of the NSS and the NCSS using identical questions. Responses from the North Carolina portion of the NSS ( n = 40 farms) and from the NCSS ( n = 139 farms) were compared for a subset of the first three questionnaires used in the NSS. Chi-square analysis was used to test for significant differences between estimated proportions from the two studies. Plots of component chi-square values and frequency distribution of differences between point estimates were used to evaluate the similarity between sections of the questionnaires. Approximately 75% of the 446 point estimates were within 15% of each other. The majority of significant discrepancies occurred for the biosecurity section of the second questionnaire, specifically for response categories of ‘No’ and ‘ N A ’ (not applicable). Percent of farms responding ‘Yes’ showed greater comparability between the two studies. While most questions from the first and third questionnaires (General Swine Farm Report and the Facilities and Feed Report) proved to be similar, questions regarding disease problems, vaccination and preventive practices were less similar between the two studies.
Scopolamine: effects on conditioned suppression.

Abstract Mice were tested with a two-chambered passive-avoidance apparatus. A mouse was placed in the apparatus, allowed a three-minute exploration period, and then either shocked the smaller compartment or returned to the home cage. Twenty-four hours later the mice were retested. Locomotor activity in the large (noshock) compartment and time spent in the small (shock) compartment were recorded. The subjects received either 0.5 mg kg of scopolamine or saline seventeen minutes prior to testing. The drug treatment increased activity and depressed the time spent in the small compartment, but did not interfere with either learning or retention of the passive avoidance response.
A general methodology for data conversion and restructuring

This paper presents a methodology and a model for data conversion or translation. The model assumes that both source and target systems are available and that conversion interfaces may be required to interact between these systems and the conversion system. To achieve data conversion or translation using this approach, two languages are needed: 1) a language to describe the data structures, and 2) a language to specify the mapping between source and target data. This paper describes these two languages, DEFINE and CONVERT and gives numerous examples to show the capabilities of these languages and how they can be used in data conversion and restructuring. Both languages are high level and nonprocedural and have the power to deal with most situations encountered in data conversion processes. In addition, the paper also describes some of the facilities in the languages specifically designed for data checking in a data conversion process.
Superconductivity in hydrides with A-15 structure

Abstract A-15 structure hydrides with the formulations of Ti3AuH and Ti3AuH2.8 were prepared and examined for superconductivity. The former has an electron-to-atom ratio generally considered favorable for superconductivity. Neither of the preparations was superconducting down to 1.6°K.
Upper bounds on value-at-risk for the maximum portfolio loss

Extremal dependence of the losses in a portfolio is one of the most important features that should be accounted for when estimating Value-at-Risk (VaR) at high levels. Multivariate extreme value theory provides a principled framework for the modeling and estimation of extremal dependence. In practice, however, this involves dealing with a challenging infinite dimensional parameter such as the spectral measure. Here, following recent developments in Schlather and Tawn (Extremes, 5(1) 87–102; 2002), Molchanov (Extremes, 11, 235–259; 2008), and Strokorb and Schlather (2013), we propose to represent extremal dependence of a multivariate portfolio via the so–called Tawn–Molchanov (TM) model, which is finite dimensional. Every max–stable random vector X can be associated with a TM max-stable vector Y = TM(X) so that the extremal coefficients of X and Ymatch and at the same time Y stochastically dominates X in the lower orthant order. This result readily yields an optimal upper bound on the value-at-risk \(\text {VaR}_{\alpha }(\mathbf {X}^{\vee })\) of the maximum portfolio loss \(\mathbf {X}^{\vee }:=\max _{j=1,\ldots ,d}X_{j}\). We develop a statistical methodology for estimating TM models from data and illustrate the resulting upper bounds on \(\text {VaR}_{\alpha }(\mathbf {X}^{\vee })\) with simulations and real data. Fitting TM models to portfolio data may be of independent practical interest, since their coefficients provide a qualitative picture of the degree and nature of diversification to extreme shocks.
TOBRAMYCIN ELUTION FROM BONE SUBSTITUTE

Purpose: To determine the rate of antibiotic elution from tobramycin-impregnated ProOsteon (Interpore) and Collagraft (Zimmer). Methods: Five samples of Collagraft and ProOsteon were impregnated with a solution containing 1.2 g of tobramycin and 10 ml of sterile water. The samples were then allowed to dry overnight. These samples were stored at 37°C in separate test tubes containing phosphate buffered saline (PBS). The solution in each test tube was removed with a pipette at hours 3, 6, 9 and 12 and days 1, 2, 3, 5, 7, 9, 11 and 13. The PBS was then replaced. The pipetted solution was sent for laboratory quantification and also used in a bioassay to determine antibiotic level. To serve as a control, two additional samples of each bone graft that were not impregnated with antibiotic were placed in separate test tubes and subjected to the same protocol. Results: The antibiotic elution rate for both ProOsteon and Collagraft was high at 3 hours [5362 and 4875 μg/ml on day 3 (3.1 μg/ml) for the Collagraft and day 7 (3.7 μg/ml) for the ProOsteon]. Effective intravenous tobramycin level is considered to be 4–6 μg/ml. Conclusion: Bone graft substitute can be used as a delivery vehicle for tobramycin. In addition, antibiotic-impregnated synthetic bone graft may potentially fill a dead space or cavitary defect without the need for large autologous grafts and does not require later removal.
Role of different isomers of the H 2 CN + ion in the formation of interstellar HCN and HNC

THE H2CN+ molecular ion is generally agreed1–4 to have a critical role in the formation of interstellar HCN and HNC. The obvious problem that H2CN+ has not yet been identified in interstellar space is complicated by considerable uncertainty due to the possible existence of three distinct isomers of H2CN+, with nuclear arrangements Brown4 stated that although the third isomer had been completely neglected in previous discussion, it is likely to have a crucial role in the formation of HNC. Brown also notes that the linear isomer, which is isoelectronic with acetylene and thus expected to lie lowest of all the isomers of H2CN+, may play no part at all in the formation of either HCN or HNC. This is from the hypothesis that the sequence thought most likely to lead to HCN is or followed by dissociative recombination Brown argues that the formation of the more stable linear isomer (1) would require the migration of a hydrogen atom from carbon to nitrogen. As this migration is expected to be very costly energetically, the H2CN+ on the right hand side of reactions (4) and (5) should be the isomer (2) above. Similarly, he argues that the sequence leading to HNC should exclusively involve isomer (3). We report here theoretical studies designed to investigate the molecular structure of (3) and its energy relative to the previously studied3 isomers (1) and (2). In addition, because reactions (4), (5) and (7) must be exothermic or very nearly so if they play a part in the interstellar medium, this question has also been assessed.
Mass operator in the light-cone representation

I argue that for the case of fermions with nonzero bare mass there is a term in the matter density operator in the light-cone representation which has been omitted from previous calculations. The new term provides agreement with previous results in the equal-time representation for mass perturbation theory in the massive Schwinger model. For the DLCQ case the physics of the new term can be represented by an effective operator which acts in the DLCQ subspace, but the form of the term might be hard to guess and I do not know how to determine its coefficient from symmetry considerations. {copyright} {ital 1999} {ital The American Physical Society}
Heat-shock protein 90 inhibitors in cancer therapy: 17AAG and beyond

Heat-shock protein 90 (HSP90) has diverse functions in mammalian cells. It acts as molecular chaperone, together with several co-chaperone molecules (such as Hop, Hip, p23, cdc37, Aha, and immunophilins). HSP90 binds to its client proteins (such as steroid receptors, AKT, Bcr-Abl, Apaf-1, survivin, cyclin dependent kinases which are involved in signal transduction that regulate cell cycle, survival, and death, and promote their proper protein folding, assembly, and transportation across different cellular compartments. Failure of Hsp90 chaperone activity leads to misfolding of client proteins, which leads to ubiquitination and proteasome degradation, and this deregulating cellular homeostasis. Since tumor cells frequently overexpress the active form of HSP90, which is more susceptible to inhibition by small molecules such as geldanamycin and its analogs, HSP90 became an attractive target for cancer therapy. This paper will review the recent advances in HSP90-biology and will discuss the emerging role of t...
Quantitative in vivo receptor binding IV: Detection of muscarinic receptor down-regulation by equilibrium and by tracer kinetic methods

Newly-developed methods for estimation of in vivo binding to neurotransmitter receptors should enable the detection and quantification of physiologic or pathologic changes in receptor numbers. In the present study, both equilibrium and kinetic experimental strategies for in vivo muscarinic receptor determination were applied to the detection of receptor changes induced by chronic inhibition of acetylcholinesterase in the rat. Following one week of treatment, in vitro receptor autoradiography utilizing [3H]scopolamine revealed significant losses of muscarinic binding in the cerebral cortex, hippocampus, striatum and in cranial nerve motor nuclei. The in vivo distribution of [3H]scopolamine, following infusion to approach equilibrium binding in the brain, revealed reductions in binding which paralleled the pattern and magnitude of changes detected in vitro. A simplified tracer kinetic estimation following bolus injection of the ligand also detected substantial reductions in forebrain muscarinic receptor binding. These results indicate the feasibility of detecting receptor changes underlying neuropathologic conditions in vivo, and suggest that either equilibrium or kinetic experimental approaches may be extended to clinical research applications with the use of positron or single-photon emission tomography.
Qualia, Space, and Control

According to representionalists, qualia-the introspectible properties of sensory experience-are exhausted by the representational contents of experience. Representationalists typically advocate an informational psychosemantics whereby a brain state represents one of its causal antecedents in evolutionarily determined optimal circumstances. I argue that such a psychosemantics may not apply to certain aspects of our experience, namely, our experience of space in vision, hearing, and touch. I offer that these cases can be handled by supplementing informational psychosemantics with a procedural psychosemantics whereby a representation is about its effects instead of its causes. I discuss conceptual and empirical points that favor a procedural representationalism for our experience of space.
Postnatal lead exposure induces supersensitivity to the stimulus properties of a D2-D3 agonist.

Abstract To examine the impact of lead (Pb) exposure during the ontogeny of dopaminergic (DA) systems on resultant DA function, rats were exposed postnatally (0–21 days of age) via the lactating dam to 0, 100 or 350 ppm Pb acetate in drinking water. At 2 months of age, the postnatally Pb-exposed rats were trained to discriminate the stimulus properties of either the D1 receptor agonist SKF38393 (6.0 mg/kg) or the D2-D3 receptor family subtype agonist quinpirole (0.05 mg/kg) from saline using a standard two-lever operant food-reinforced drug discrimination paradigm. In each training group, dose-effect curves describing drug lever responding to lower doses of the training drug and to preadministration of selective DA antagonists were obtained to examine Pb-induced changes in DA sensitivity. Doses of other DA agonists were substituted for the training drug to determine the generality of any changes in DA sensitivity, and doses of non-DA compounds were substituted to determine the specificity of any changes in DA sensitivity. In the D1/saline training condition, Pb exposure was not associated with any specific or consistent changes in DA sensitivity. In contrast, exposure to Pb was associated with D2-D3 receptor subtype supersensitivity as was indicated by significantly elevated levels of drug lever responding in the presence of quinpirole and haloperidol and to at least one dose of apomorphine. No differences in the dose-effect curves for either (+)-amphetamine or NMDA were observed in the D2-D3-trained control and Pb-exposed groups, but an increase in drug lever responding in the presence of pentobarbital was noted in the Pb-exposed group relative to control. Taken together, these findings are consistent with a Pb-induced functional D2-D3 supersensitivity possibly mediated via autoreceptors. Moreover, this functional D2-D3 supersensitivity necessarily represents a permanent effect of postnatal Pb exposure since both blood and brain Pb levels were negligible at the time drug discrimination training began.
Migration of Plant Bugs and the Potato Leafhopper in a Soybean-Alfalfa Complex

Field experiments were conducted during 1972 and 1973 to ascertain and quantify certain insect-pest migrations from alfalfa to soybeans after alfalfa cutting. Twelve soybean-alfalfa complexes were established and sampled before and after cutting. During 1972 the Empoasca fabae (Harris) migration into soybeans, following alfalfa cutting, was detected only in the border rows of the cut complexes, but was observed throughout the plots in 1973. Inadequate numbers of Lygus lineolaris (Palisot de Beauvois) and Aldelphocoris lineolatus (Goeze) were collected during 1972 to evaluate treatment effects. During 1973 L. lineolaris (nymphs and adults) migration was restricted to the soybean border rows, and A. lineolatus (adults) migration occurred throughout the soybean plot.
Distinct Mechanisms for Ca2+ Entry Induced by OKT3 and Ca2+ Depletion in Jurkat T Cells

Abstract Ca 2+ influx triggered by antigen binding to T cell receptors (TCR) is an early event in T cell activation. An additional (Ca 2+ influx induced by depletion of intracellular Ca 2+ (CDCI) has been characterized in human Jurkat T cells that is both temporally and mechanistically distinct from TCR-mediated Ca 2+ influx (TCRCI). Both TCRCI and CDCI were insensitive to voltage-gated Ca 2+ channel antagonists (e.g., nifedipine, verapamil, and ω-conotoxin G) and pertussis toxin, yet were voltage-sensitive and inhibited by SKF 96365 (a receptorgated Ca 2+ channel blocker) and cholera toxin. However, TCRCI but not CDCI was associated with a significant increase in inositol phosphate (IP x ) levels and inhibited by phorbol ester, while CDCI but not TCRCI was inhibited by Sr 2+ , forskolin (FSK), and 1,9-dideoxy FSK in a cAMP-independent fashion. Moreover, TCR stimulation did not deplete thapsigargin-sensitive Ca 2+ stores, suggesting that TCRCI is not merely a consequence of Ca 2+ depletion. These results indicate that Ca 2+ entry following the depletion of intracellular Ca 2+ stores or TCR stimulation occur through distinct cellular mechanisms coexisting in Jurkat T cells.
Neither novice nor expert: the discretionary user of software

Abstract Most studies that examine users' interaction with computers focus either on novices or experts. Discretionary users of computers, such as lawyers, executives, administrators and professors have been ignored. Using techniques of process analysis, this study investigated the characteristics of discretionary users by observing their interaction with commercial word-processing software. Their performance was compared to groups of novices and experts. Results indicate that discretionary users exhibit expert-like characteristics on a small set of routine editing tasks, beyond which their behavior is quite novice-like. A procedural model that indicates areas where software design could improve the editing performance of discretionary users is also discussed.
EQUATIONS FOR VAPOR FLUX AS A FULLY TURBULENT DIFFUSION PROCESS UNDER DIABATIC CONDITIONS

Abstract Equations are derived for vapor transport within a constant flux layer of the atmosphere. The physical model is based on the Reynolds analogy for fully turbulent flow, so that vapor and momentum flux are assumed similar. The shear stress is deduced from analysis of the wind profile by means of equations available for non-neutral conditions. Empirical expressions are proposed using the friction velocity rather than the wind velocity at a given level in order to take account of the stability of the air.
Early B-lymphocyte precursors and their regulation by sex steroids.

Summary: This review describes an improved characterization of early B-lymphocyte precursors in mice and the remarkable sensitivity of the same cells to hormones. The nuclear enzyme terminal deoxynucleotidyl transferase (TdT) was used as a marker to image and characterize bone marrow cells lacking all lineage-associated markers. Most early TdT+ precursors have a distinctive density of c-kit and express the interleukin-7Ra chain, as well as flt-3/flk2, but lack CD34. An understanding of those cell surface properties made it possible to obtain highly enriched, viable cells with the potential to give rise to CD19+ lymphocytes in culture. A series of other flow cytometry and culture experiments suggested a possible differentiation sequence for these early pro-B cells. This new model was used to advantage in our studies of sex steroids. It appears that early precursors represent a hormone-sensitive control point for determining numbers of new B lymphocytes that are produced within bone marrow. We also compare and contrast these findings with B lymphopoiesis in humans.
Evolution of Microstructure for Laser Clad Fe-Cr-Mn-C Alloys

The laser surface cladding technique was used to form in situ Fe-Cr-Mn-C alloys on AISI 1016 steel substrate. In this process mixed powders containing Cr, Mn, and C with a ratio of 10:1:1 were delivered using a screw feed, gravity flow carrier gas aided system into the melt pool generated by a 10 kW CO 2 laser. This technique produced ultrafine microstructure in the cladded alloy. The microstructure of the laser surface cladded region was investigated by optical, scanning and transmission electron microscopy and x-ray microanalysis techniques. Microstructural study showed a high degree of grain refinement and an increase in solid solubility of alloying elements which, in turn, produced a fine distribution of complex types of carbide precipitates in the ferrite matrix because of the high cooling rate. An alloy of this composition does not show any martensitic or retained austenite phase.
Levels of interaction and proximity: Content analysis of video-based classroom cases

This study employed content analysis techniques to examine video-based cases of two websites that exemplify learner-centered pedagogies for pre-service teachers to carry out in their teaching practices. The study focused on interaction types and physical proximity levels between students and teachers observed in the videos. The findings regarding interaction demonstrated that video cases were more focused on teacher-centered interactions than learner-centered interactions. In terms of proximity, the analysis revealed that reciprocal interaction between students and teacher was most likely to happen if their physical distance from each other was the greatest. Findings and directions for future research are discussed in terms of the content of online video-based classroom cases.
Star Power? Advocacy, Receptivity, and Viewpoints on Celebrity Involvement in Issue Politics

Recognizing the ever-increasing involvement of celebrities in political life, the current study presents an empirical investigation of the impact of celebrity issue politics in the post-2008 election environment. Relying on experimental data collected in the fall of 2009, initial results suggest that the less politically important an issue, the more appropriate it is for celebrities to promote their own viewpoint. The second analysis highlights significant positive relationships between exposure to celebrity issue advocacy appeals and receptivity toward celebrity involvement in politics. Implications of the findings are discussed.
Derivation of the Fluctuation-Dissipation Theorem

A simple derivation is given of the fluctuation-dissipation theorem or generalized Nyquist formula. The proof is based on a solution of the Langevin equation for a thermodynamic variable according to Ornstein's method; in this way the correlation function and the spectrum are obtained directly in the desired form.
Effects of prey concentration, prey size, predator life stage, predator starvation, and season on predation rates of the carnivorous copepod Euchaeta elongata

Adult females of the large carnivorous copepod Euchaeta elongata Esterly were collected from 1977 to 1980 in Port Susan, Washington, USA. Predation rates of the adult females increased with increasing prey abundance when fed the following 4 sizes of copepods: adult females of Calanus pacificus (average prosome length [PL] of 2 650 μm), adults of Aetideus divergens (PL of 1 560 μm), adult females of Pseudocalanus spp. (PL of 1 060 μm), and nauplii of C. pacificus (PL of 410 μm). Saturation feeding levels were reached when adult females of the predator were fed the small adult copepod, Pseudocalanus spp. Maximum biomass ingested of this small copepod was more than the maximum amount ingested of the larger copepods. Predation rates of the predatory copepodids at Stages IV and V also increased with increasing concentration of the 1 060 μm (PL) prey. High feeding rates exhibited by both adults and copepodids at Stage V of the predator indicate their importance as sources of mortality on populations of small copepods. Ingestion efficiency E i (prey wholly consumed [prey attacked]-1) varied as follows: adults of E. elongata were more efficient than copepodids of E. elongata; adults were more efficient than copepodids when ingesting smaller prey; starved adults were more efficient than fed ones; and both adults and copepodids were more efficient at low food concentrations. For adults of E. elongata, there were no marked seasonal variations in predation or respiratory rates that would represent acclimatory responses; however, small adults obtained during winter were more efficient at ingesting prey than were the larger adults gathered in summer. This seasonal variation in the efficiency of ingestion may be a useful indicator of physiological state: high E i values could indicate that predators are starving in winter, and low E i values could indicate that predators are satiated in summer.
Cannabinoids attenuate depolarization-dependent Ca2+ influx in intermediate-size primary afferent neurons of adult rats.

CB1 receptors have been localized to primary afferent neurons, but little is known about the direct effect of cannabinoids on these neurons. The depolarization-evoked increase in the concentration of free intracellular calcium ([Ca2+]i), measured by microfluorimetry, was used as a bioassay for the effect of cannabinoids on isolated, adult rat primary afferent neurons 20–28 h after dissociation of dorsal root ganglia. Cannabinoid agonists CP 55,940 (100 nM) and WIN 55,212-2 (1 μM) had no effect on the mean K+-evoked increase in [Ca2+]i in neurons with a somal area<800 μm2, but the ligands attenuated the evoked increase in [Ca2+]i by 35% in neurons defined as intermediate in size (800–1500 μm2). The effects of CP 55,940 and WIN 55,212-2 were mediated by the CB1 receptor on the basis of relative effective concentrations, blockade by the CB1 receptor antagonist SR141716A and lack of effect of WIN 55,212-3. Intermediate-size neurons rarely responded to capsaicin (100 nM). Although cannabinoid agonists generally did not inhibit depolarization-evoked increases in [Ca2+]i in small neurons, immunocytochemical studies indicated that CB1 receptor-immunoreactivity occurred in this population. CB1 receptor-immunoreactive neurons ranged in size from 227 to 2995 μm2 (mean somal area of 1044 μm2). In double labeling studies, CB1 receptor-immunoreactivity co-localized with labeling for calcitonin gene-related peptide and RT97, a marker for myelination, in some primary afferent neurons. The decrease in evoked Ca2+ influx indicates that cannabinoids decrease conductance through voltage-dependent calcium channels in a subpopulation of primary afferent neurons. Modulation of calcium channels is one mechanism by which cannabinoids may decrease transmitter release from primary afferent neurons. An effect on voltage-dependent calcium channels, however, represents only one possible effect of cannabinoids on primary afferent neurons. Identifying the mechanisms by which cannabinoids modulate nociceptive neurons will increase our understanding of how cannabinoids produce anti-nociception in normal animals and animals with tissue injury.
The Formation of Starch in Leaves of Bryophyllum Calycinum Cultured in Darkness.

In experiments carried out in this laboratory several years ago, it was noted that excised leaves of Bryophyllum calycinum collected at daybreak and cultured in water in darkness may increase appreciably in their content of starch (3). Such leaves contain a high proportion of organic acids when picked but undergo a marked loss of acidity when kept in darkness for two or three days. The suggestion was advanced that the newly formed starch may have arisen from organic acids as a result of reversal of the glycolytic reactions. Experiments on the normal diurnal variation respectively of organic acids and starch in Bryophyllum leaves (4, ?) have lent considerable support to the view that such a course of events is possible, and an unpublished experiment carried out by the late Dr. G. W. Pucher shortly before his death in 1947 showed that starch accumulation in leaves cultured in darkness may at times reach considerable proportions. Accordingly, renewed study has been given to this problem. Bryophyllum calycinum leaves collected at daybreak were maintained in a closed dark cabinet under a continuous fine spray of water for several days, individual samples being removed for analysis at appropriate times. The leaves, which contained 3.7 gm. per kilo of initial fresh weight of starch at dawn, contained only 1 gm. after a further seven hours in darkness but then began to accumulate starch so that, after 26 hours, they contained 3 gm. and, after 75 hours, 3.6 gm. An even larger relative increase had been observed in the unpublished experiment of Pucher (see also 3) so that there appears to be no doubt of the capacity of Bryophyllum leaves to behave in this manner, notwithstanding a report to the contrary of Varner and BurRELL (5).
Capacitive Properties of Body Tissues

The electric capacity of various tissues surrounding the heart has been investigated in living dogs, using frequency ranges from 10 to 10,000 c.p.s. Electrode polarization, a serious source of error in such measurements, has been corrected for. Discussion of our results and of resistivity data previously obtained in body tissues proves that the electric properties of body tissues are primarily resistive ones.
Manganese Reduction by Microbes from Oxic Regions of the Lake Vanda (Antarctica) Water Column

Depth profiles of metals in Lake Vanda, a permanently ice-covered, stratified Antarctic lake, suggest the importance of particulate manganese oxides in the scavenging, transport, and release of metals. Since manganese oxides can be solubilized by manganese-reducing bacteria, microbially mediated manganese reduction was investigated in Lake Vanda. Microbes concentrated from oxic regions of the water column, encompassing a peak of soluble manganese [Mn(II)], reduced synthetic manganese oxides (MnO2) when incubated aerobically. Pure cultures of manganese-reducing bacteria were readily isolated from waters collected near the oxic Mn(II) peak. Based on phylogenetic analysis of the 16S rRNA gene sequence, most of the isolated manganese reducers belong to the genus Carnobacterium. Cultures of a phylogenetically representative strain of Carnobacterium reduced synthetic MnO2 in the presence of sodium azide, as was seen in field assays. Unlike anaerobes that utilize manganese oxides as terminal electron acceptors in respiration, isolates of the genus Carnobacterium reduced Mn(IV) via a diffusible compound under oxic conditions. The release of adsorbed trace metals accompanying the solubilization of manganese oxides may provide populations of Carnobacterium with a source of nutrients in this extremely oligotrophic environment.
CARDIAC POSITRON EMISSION TOMOGRAPHY (PET) FOR BEGINNERS

Cardiac positron emission tomography (PET) is finding increasing use as a measure of the effectiveness of antiatherosclerosis therapies. PET is a computer tomographic technique used to generate images of the three-dimensional distribution of a positron-emitting tracer. The positron-emitting tracer N-13 ammonia can be used to generate images representing myocardial perfusion, and PET images recorded under conditions of acute stress with this tracer can be used to locate coronary artery stenosis. Three-dimensional myocardial perfusion data can be represented in a single image called a polar coordinate map and can, together with a tracer-kinetic model, be used to quantitate myocardial blood flow in real terms. Calculation of myocardial blood flow forms the basis of definition of a number of parameters for the measure of myocardial perfusion, including coronary flow reserve and coronary resistance. Three-dimensional myocardial perfusion data can also be used for semiquantitative image analysis.
Duplicate Laboratory Test Reduction Using a Clinical Decision Support Tool

Objectives Duplicate laboratory tests that are unwarranted increase unnecessary phlebotomy, which contributes to iatrogenic anemia, decreased patient satisfaction, and increased health care costs. Materials and Methods We employed a clinical decision support tool (CDST) to block unnecessary duplicate test orders during the computerized physician order entry (CPOE) process. We assessed laboratory cost savings after 2 years and searched for untoward patient events associated with this intervention. Results This CDST blocked 11,790 unnecessary duplicate test orders in these 2 years, which resulted in a cost savings of $183,586. There were no untoward effects reported associated with this intervention. Conclusions The movement to CPOE affords real-time interaction between the laboratory and the physician through CDSTs that signal duplicate orders. These interactions save health care dollars and should also increase patient satisfaction and well-being.
Correlations of partial and extensive methylation at the p14ARF locus with reduced mRNA expression in colorectal cancer cell lines and clinicopathological features in primary tumors

p14(ARF) is a putative tumor suppressor gene thought to modify the levels of p53. CpG sites within the 5'-flanking region and exon 1beta of p14(ARF) are targets of aberrant methylation and transcriptional silencing in human colorectal cancer (CRC). Here we have developed methylation-specific polymerase chain reaction (MSPCR) methods to detect methylation of CpG sites in p14(ARF) in CRC cell lines and primary CRC tumors, and correlated p14(ARF) mRNA expression with methylation in CRC cell lines using competitive quantitative reverse transcription-polymerase chain reaction methods. Ten CRC cell lines were studied; three (DLD-1, HCT15 and SW48) showed extensive methylation and six (Colo320, SW480, HT29, Caco2, SW837 and WiDr) were unmethylated; the other cell line, LoVo, showed partial methylation that affected exon 1beta but not the immediate upstream CpG sites. p14(ARF) mRNA was expressed at extremely low levels in fully methylated cell lines and at 10(4)- to 10(5)-fold higher levels in unmethylated cell lines. p14(ARF) expression in the partially methylated LoVo cell line was intermediate. Treatment of LoVo cells with 2 microM 5-aza-2'-deoxycytidine for 72 h was associated with marked (100-fold) induction of mRNA levels. Of 119 primary CRCs, 18% contained p14(ARF) methylation, although partial methylation was the most common pattern observed (in 67% of methylated tumors). Methylation of p14(ARF) was often accompanied by p16(INK4a) methylation; however, 50% of p14(ARF) methylated tumors contained unmethylated p16(INK4a). Methylation at p14(ARF) was associated with female gender, greater age, proximal anatomic location and poor differentiation, but not stage at diagnosis. A two-step MSPCR method for assaying p14(ARF) methylation in human tumors is described.
Response to Alroy

Alroy is correct. My error—and it was mine alone and not my coauthor's—can be traced to the following sentence …
Iterative Evolution of Sympatric Seacow (Dugongidae, Sirenia) Assemblages during the Past ~26 Million Years

Extant sirenians show allopatric distributions throughout most of their range. However, their fossil record shows evidence of multispecies communities throughout most of the past ∼26 million years, in different oceanic basins. Morphological differences among co-occurring sirenian taxa suggest that resource partitioning played a role in structuring these communities. We examined body size and ecomorphological differences (e.g., rostral deflection and tusk morphology) among sirenian assemblages from the late Oligocene of Florida, early Miocene of India and early Pliocene of Mexico; each with three species of the family Dugongidae. Although overlapping in several ecomorphological traits, each assemblage showed at least one dominant trait in which coexisting species differed. Fossil sirenian occurrences occasionally are monotypic, but the assemblages analyzed herein show iterative evolution of multispecies communities, a phenomenon unparalleled in extant sirenian ecology. As primary consumers of seagrasses, these communities likely had a strong impact on past seagrass ecology and diversity, although the sparse fossil record of seagrasses limits direct comparisons. Nonetheless, our results provide robust support for previous suggestions that some sirenians in these extinct assemblages served as keystone species, controlling the dominance of climax seagrass species, permitting more taxonomically diverse seagrass beds (and sirenian communities) than many of those observed today.