cssi/SciSciGPT-SciSciNet huggingface dataset:
Quantitative assessment of myocardial perfusion during graded coronary stenosis by real-time myocardial contrast echo refilling curves.

OBJECTIVES The present study examined the ability of real-time myocardial contrast echocardiography (MCE) to delineate abnormalities produced by graded coronary stenoses and to correlate signal intensity (SI) parameters derived from destruction/refilling curves with regional myocardial blood flow (MBF) and contractile function. BACKGROUND Recent technological advances have enabled myocardial opacification by MCE to be achieved during real-time imaging. METHODS In eight open-chest dogs, we created LAD occlusion and graded stenoses that were either flow-limiting at rest (FLS) or reduced adenosine hyperemia (non-flow-limiting at rest = NFLS). Myocardial contrast echo used Optison infusion and low-energy real-time power pulse inversion imaging. High-energy FLASH frames destroyed bubbles every 15 cardiac cycles. Myocardial SI-versus-time plots were fitted to a one-exponential function to obtain the rate of SI rise (b) and peak SI in the last frame. RESULTS Dyssynergy was not observed during any NFLS, but perfusion abnormalities were. Visual detection of decreased opacification was possible with severe NFLS and FLS. b demonstrated a significant reduction with severe NFLS and near significant with moderate NFLS; peak SI did not. All exponential parameters were significantly decreased with FL stenosis and occlusion. The MBF ratio in LAD/LCx beds (fluorescent microspheres) correlated with b (r = 0.79) and the product of the peak SI and b (r = 0.80). CONCLUSIONS In an open-chest dog model, parameters derived from microbubble refilling of the imaging field by real-time MCE correlate well with myocardial blood flow and can identify coronary stenosis.
Optical Absorption due to Space-Charge Induced Localized States

A self-consistent model of the space-charge potential in narrow, degenerate accumulation regions at a planar semiconductor interface is constructed and applied to evaluate the binding energies and wave functions of quantized, localized states for motion normal to the interface. The model attributes the space-charge potential entirely to charge trapped in the two-dimensional energy bands associated with the localized states. Expressions are derived for the contributions to the absorption coefficient due to vertical transitions among the two-dimensional bands and due to interband transitions in which either the initial or final state is localized near the interface. The results of numerical calculations are presented for $n$-type accumulation regions in GaAs and at the (100) surface of silicon. Experimental observation of the structure in the absorption coefficient at infrared frequencies appears to be practical, and would provide a direct observation of quantization effects in narrow accumulation or inversion channels at semiconductor surfaces.
Conditional matching preclusion for the arrangement graphs

The matching preclusion number of a?graph is the minimum number of edges whose deletion results in a?graph that has neither perfect matchings nor almost-perfect matchings. For many interconnection networks, the optimal sets are precisely those induced by a?single vertex. Recently, the conditional matching preclusion number of a?graph was introduced to look for obstruction sets beyond those induced by a?single vertex. It is defined to be the minimum number of edges whose deletion results in a?graph with no isolated vertices that has neither perfect matchings nor almost-perfect matchings. In this paper we find this number and classify all optimal sets for the arrangement graphs, one of the most popular interconnection networks.
Effect of hot pressing time and temperature on the microstructure and mechanical properties of ZrB2-SiC

Structure–property relations were examined for ZrB2 containing 30 volume percent SiC particulates. Two grades of ZrB2 with initial particle sizes of 2 and 6 μm were used. Billets of ZrB2–SiC were produced by hot pressing at 1850, 1950 or 2050 °C for 45 min. In addition, the material prepared from ZrB2 with an initial particle size of 2 μm was hot pressed at 2050 °C for 90 and 180 min. Microstructures and mechanical properties were characterized to determine the effects of the initial particle size, hot pressing time, and hot pressing temperature on the final grain size and morphology. The average grain size of the ZrB2 phase ranged from 2.2 to 4.7 μm. Similarly, the average grain size of the SiC phase ranged from 1.2 to 2.7 μm. Hardness and modulus of elasticity were not affected by the processing conditions with average values of 22 and 505 GPa, respectively. However, flexural strength decreased as grain size increased from a maximum of ∼1050 MPa for the finest grain sizes to ∼700 MPa for the largest grain sizes. Analysis suggested that the strength of ZrB2–SiC was limited by the size of the SiC inclusions in the ZrB2 matrix.
Volume transport in the Alaska Coastal Current

Abstract Nine moorings were deployed in three sections in the Shelikof Strait/Semidi Islands region of the Alaskan continental shelf during the period of August 1984 to July 1985. Analysis of the resulting current and bottom pressure data, together with surface wind, provides a new understanding of transport in the Alaska Coastal Current. Using current observations, mean volume transport through the Shelikof sea valley was computed to be 0.85 × 106 m3 s−1, which is in good agreement with estimates of transport obtained from hydrographic data. Approximately 75% of this flux flowed seaward through the Shelikof sea valley, with the remainder flowing along the Alaska Peninsula. Data showed the expected increase of volume transport concomitant with maximum freshwater discharge in autumn. The greatest monthly mean transport, however, occurred in winter and was related to wind forcing. On time intervals of days, fluctuations in transport were often large (up to 3.0 × 106 m3 s−1), and generally geostrophic (r = 0.79). Some of these fluctuations resulted from convergence of flow caused by the complex interaction of storms with orography. Approximately half of the fluctuations in volume transport were accounted for by the alongshore wind.
Development and Evaluation of an Intelligent Energy-Management Strategy for Plug-in Hybrid Electric Vehicles

There has been significant interest in plug-in hybrid electric vehicles (PHEVs) as a means to decrease dependence on imported oil and to reduce greenhouse gases as well as other pollutant emissions. One of the critical considerations in PHEV development is the design of its energy-management strategy, which determines how energy in a hybrid powertrain should be produced and utilized as a function of various vehicle parameters. In this paper, we propose an intelligent energy-management strategy for PHEVs. At the trip level, the strategy takes into account a priori knowledge of vehicle location, roadway characteristics, and real-time traffic conditions on the travel route from intelligent transportation system technologies in generating a synthesized velocity trajectory for the trip. The synthesized velocity trajectory is then used to determine battery's charge-depleting control that is formulated as a mixed-integer linear programming problem to minimize the total trip fuel consumption. The strategy can be extended to optimize vehicle fuel consumption at the tour level if a preplanned travel itinerary for the tour and the information about available battery recharging opportunities at intermediate stops along the tour are available. The effectiveness of the proposed strategy, both for the trip- and tour-based controls, was evaluated against the existing binary-mode energy-management strategy using real-world trip/tour examples in southern California. The evaluation results show that the fuel savings of the proposed strategy over the binary-mode strategy are around 10%–15%.
Magnetism in 4d Transition Metal–Ag(001) Sandwiches

Using ab-initio spin-polarized layer Korringa-Kohn-Rostoker (LKKR) band structure calculations, we investigated the possibility of having a stable ferromagnetic ground state in 4d transition metal (TM)-Ag(001) sandwiches (TM = Tc, Ru, Rh, and Pd). In contrast to recent calculations performed on systems with TM overlayers on Ag (001), we find that the TM sandwich configuration gives a paramagnetic ground state. While excellent agreement in general is obtained for the layer-projected densities of states (LDOS), the sandwich configuration lowers the densities of states at the Fermi energy (EF) in the case of Rh and Ru by a small amount which seemingly prevents the marginal ferromagnetic instability predicted by Eriksson et. al. (Phys. Rev. Lett. 66, 1350 (1991)) from occurring.
The Historical Violence Database: A Collaborative Research Project on the History of Violent Crime, Violent Death, and Collective Violence

The Historical Violence Database (HVD) is a collaborative research project to gather data on the history of violent crime, violent death, and collective violence. The database will serve as a repository for historical research (research notes, handwritten worksheets, spreadsheets, scans and photographs of original documents, etc.) and will integrate that research into a single information system based on standard worksheets and spreadsheets. The goal is to create a "calendar of cases" that can be amended and augmented. The HVD will also serve as an archive for historic data compiled by public agencies and for early town and county histories that studied violence.
Clues to the fundamental properties of high temperature superconductors

Abstract Are there properties of high temperature superconductors, or specific phenomena in some of them, that constitute “smoking guns” — signals that clearly guide us toward the appropriate picture, or at least rule out some possibilities? Possible gun racks include: phase diagram, transport properties, magnetic phenomena, optical characteristics, and superconducting properties. An example of the difficulty in identifying smoking guns is the verification and mapping out of the Fermi surface of YBa 2 Cu 3 O 7 : it is a veritable smoking assault rifle that has narrowed speculation considerably, yet there are still arguments that the normal state of the high T c , phase is not a conventional Fermi liquid. This Fermi liquid question has been discussed sufficiently in the literature; here I briefly discuss a few other recently emphasized phenomena as possible smoking guns.
Nonmetric cranial variation and divergence of European sousliks (Citellus citellus) from Yugoslavia (Rodentia, Sciuridae)

Abstract Variation in 25 nonmetric cranial traits was assessed for 107 adult skulls from 5 populations of Citellus citellus of the Pannonian Plain and Macedonia (Yugoslavia). The Mean Measure of Divergence (MMD), based on trait frequencies, was used to express the interpopulation differences. Three samples from the Pannonian Plain were relatively similar to each other; however, they differed from the two Macedonian samples. The results suggested the existence of three subspecies, two from Macedonia and one from the Pannonian Plain. Differences among souslik populations were ascribed to a divergence caused by allopatry.
Transactivation of gene expression by Myc is inhibited by mutation at the phosphorylation sites Thr-58 and Ser-62.

Abstract The product of the human c-myc protooncogene (Myc) is a sequence-specific DNA binding protein. Here, we demonstrate that the placement of the specific Myc DNA binding site CACGTG upstream of a luciferase reporter gene conferred Myc-stimulated expression that was inhibited by the overexpression of the basic-helix-loop-helix/leucine zipper protein Max. It was observed that Myc was phosphorylated in vivo within the NH2-terminal domain at Thr-58 and Ser-62. Replacement of these phosphorylation sites with Ala residues caused a marked decrease in Myc-stimulated reporter gene expression. In contrast, the replacement of Thr-58 or Ser-62 with an acidic residue (Glu) caused only a small inhibition of transactivation. Together, these data demonstrate that the NH2-terminal phosphorylation sites Thr-58 and Ser-62 are required for high levels of transactivation of gene expression by Myc.
Microstructural Effects on the Thermal Conductivity of Polycrystalline Aluminum Nitride

Polycrystalline AIN bodies were made with a range of porosities from various AIN powders by sintering or hot-pressing. Thermal conductivity data for material produced without sintering aids showed a gradual, yet definite, porosity dependence with scatter similar to other property-porosity studies. The thermal conductivity-porosity data for ALN with sintering aids showed the existence of two distinct regions: (1) a higher-porosity region (greater than approximately 2%) which was similar to the data for material without sintering aids, and (2) a low-porosity region where grain boundaries were seen to dominate thermal conductivity. Auger spectroscopy was used to investigate fracture surfaces for dense CaO-doped materials. Thermal conductivity was observed to correlate to effective grain-boundary thickness, which was calculated from quantitative analysis of the Auger data. A model consisting of cubic grains in a continuous grain-boundary phase accurately describes these data.
Congenitally absent thoracic pedicle in a child with rhabdomyosarcoma

A case of congenital absence of a thoracic pedicle is reported in a 9 year old boy with embryonal rhabdomyosarcoma of the eyelid. In this clinical setting a surgical exploration was necessary in order to differentiate a developmental anomaly from an acquired metastatic deposit.
Tests in Japan on the performance of salt-contaminated insulators in natural and artificial humid conditions

The paper describes experimental work carried out at the Shiobara Laboratory on the performance of salt-contaminated insulators in both natural and artificial humid conditions. The purpose was to analyse, in relation to humidity, one type of flashover mechanism caused by salinity deposited on a porcelain surface and absorbed moisture in humid conditions. For natural humid conditions, dew, fog and drizzle were available. Based on experience of natural humid conditions, an artificial test with steam fog permitting the gradual formation of humid conditions, was developed. This method produced a flashover voltage of the insulators similar to that in natural conditions. An antifog-type insulator showed the best performance for the insulators that have similar flashover voltage. However, flashover voltages of the two long-term tests showed a great difference from that of the conventional short-term test. A hypothesis of `danger degree for flashover?, is assumed in order to explain the essential differences between the pollution- test methods and results. The danger-degree concept is a combination of two factors: transfer of salinity and humidity
Synthesis of selective inhibitors against V. cholerae sialidase and human cytosolic sialidase NEU2

Sialidases or neuraminidases catalyze the hydrolysis of terminal sialic acid residues from sialyl oligosaccharides and glycoconjugates. Despite successes in developing potent inhibitors specifically against influenza virus neuraminidases, the progress in designing and synthesizing selective inhibitors against bacterial and human sialidases has been slow. Guided by sialidase substrate specificity studies and sialidase crystal structural analysis, a number of 2-deoxy-2,3-dehydro-N-acetylneuraminic acid (DANA or Neu5Ac2en) analogues with modifications at C9 or at both C5 and C9 were synthesized. Inhibition studies of various bacterial sialidases and human cytosolic sialidase NEU2 revealed that Neu5Gc9N32en and Neu5AcN39N32en are selective inhibitors against V. cholerae sialidase and human NEU2, respectively.
Anisotropy in the Antiferromagnetic Mn F 2

The major part of the anisotropy in the paramagnetic susceptibility of Mn${\mathrm{F}}_{2}$ above the Curie point, as measured by Stout and Griffel, can be accounted for by magnetic dipole interactions. These interactions affect the anisotropy in different ways above and below the Curie point and lead to an anisotropy field of the order of 8800 oersteds at O\ifmmode^\circ\else\textdegree\fi{}K. Other sources of anisotropy in antiferromagnetics are discussed, in particular that due to crystalline fields which is also present in magnetically dilute paramagnetic salts. The anisotropy field below the Curie point can be measured by antiferromagnetic resonance. It is predicted that this will require wavelengths of 1 mm at 0\ifmmode^\circ\else\textdegree\fi{}K increasing to perhaps 2 mm at $0.9{T}_{c}$. Or one may use centimeter waves and static fields of 1.0\ifmmode\times\else\texttimes\fi{}${10}^{5}$ oersteds at 0\ifmmode^\circ\else\textdegree\fi{}K increasing to perhaps 1.7\ifmmode\times\else\texttimes\fi{}${10}^{5}$ oersteds at $0.9{T}_{c}$.
Direct crystallographic observation of an acyl-enzyme intermediate in the elastase-catalyzed hydrolysis of a peptidyl ester substrate : Exploiting the glass transition in protein dynamics

Abstract The crystal structure of the acyl complex of porcine pancreatic elastase with its peptidyl ester substrate N-acetyl-ala-ala-ala-methyl ester (Ac(Ala)3OMe) has been determined at 2.5 A resolution. The complex was stabilized by exploiting the “glass transition” in protein dynamics that occurs at around −53 °C (220 K). Substrate was flowed into the crystal in a cryoprotective solvent above this temperature, and then the crystal was rapidly cooled to a temperature below the transition to trap the species that formed. The use of a flow cell makes the experiment a kinetic one and means that the species prior to the rate determining transition state has a chance to accumulate. The resulting crystal structure shows an acyl-enzyme intermediate in which the leaving group is absent and the carbonyl carbon of the C-terminal alanine residue is covalently bound to the gamma oxygen of the active site serine. The ester carbonyl shows no significant distortion from planarity, with the carbonyl oxygen forming one hydrogen bond with the oxyanion hole. The tripeptide is bound in an extended antiparallel β-sheet with main chain residues of the enzyme. The geometry and interactions of this acyl-enzyme suggest that it represents a productive intermediate. To test this hypothesis, the same crystal was then warmed above the glass transition temperature and a second data set was collected. The resulting electron density map shows no sign of the substrate, indicating hydrolysis of the intermediate followed by product release. This experiment provides direct evidence for the importance of dynamic properties in catalysis and also provides a blueprint for the stabilization of other short-lived species for direct crystallographic observation.
The relationship between eating disorders and running in women

The purpose of this study was to determine the extent to which eating disorders in women are related to a general tendency toward addiction, addiction to running, and level of running intensity. A stratified sample of 265 women runners/nonrunners (ages 20-35) included 66 nonrunners, 69 low-level runners, 67 medium-level runners, and 63 high-intensity runners. The women were weighed, measured, and had body fat and 4-day nutritional intake assessed. A questionnaire included scales to assess psychological and behavior traits common in women with anorexia (AN) and/or bulimia, general addiction, and running addiction. ANCOVA with age and income as covariates and multiple regression analyses were used. There were significant differences among the groups on the eating disorder scores and percent body fat with higher level runners scoring higher on eating disorder measures and running addiction and lower on body fat. A major finding for those providing health care for women was that 25% of the women who ran >30 miles/week had Eating Attitude Test scores indicating a high risk for anorexia.
Where worlds collide: taking quantum weirdness into space

What happens when our two greatest theories of reality, quantum theory and relativity, collide? Soon they could be slugging it out above our heads
Partial purification and characterization of 12-lipoxygenase in bullfrog erythrocytes.

Abstract 12-Lipoxygenase (12-LO) in bullfrog ( Rana catesbeiana ) erythrocytes was purified partially by ion exchange chromatography and affinity chromatography. Bullfrog 12-LO was a single chain protein with a pI of 7.1–7.8 and MW of 7.77 kDa. This enzyme did not show typical Michaelis–Menten type kinetics. At low substrate concentrations, it had a lag phase and at higher substrate concentrations, the activity was inhibited. The product of linoleic acid (LA), 13-hydroperoxy-9, 11-octadecadienoic acid (13-HpODE), was an activator for the enzyme. When arachidonic acid (AA) was used as substrate, 13-HpODE also affected the K m of bullfrog 12-LO towards AA. The affinity of LA towards bullfrog 12-LO was higher than the affinity of AA. Suicide inactivation was much more rapid than that of any mammalian 12-LO reported. Hemoglobin (Hb) inhibited the activity of 12-LO partially and removing Hb eliminated this inhibition. Both Hb and Met-Hb inhibited the 12-LO activity but did not denatured completely the Hb, suggesting that the inhibition was a direct interaction between 12-LO and Hb protein chain and was not due to competition between 12-LO and Hb for oxygen. This study characterizes bullfrog 12-LO with respect to stability, optimal pH, suicide inactivation and interaction with Hb and provides important evolutionary information about this enzyme.
Studies of repressed memory and the issue of legal validity.

In the 1990s the prosecution of individuals charged with sexual abuse based on the uncovering of a victim's repressed memory has become increasingly common. Those prosecutions have been facilitated by changes made by nearly every state in their civil and criminal statutes of limitations for incidents involving sexual abuse of children. Many of these changes, even if not made in response to social scientific studies, without doubt stemmed from the belief that victims are likely to repress memories of childhood sexual abuse for extended periods of time. The studies conducted by Key, Warren, and Ross (1996) and Golding, Sego, Sanchez, and Hasemann (1995) are the most recent contributions to the law and psychology literature on the topic. As they were published in the premier law and psychology journal, they will receive considerable attention, making it likely that attempts will be made to replicate them. Thus it is important that we discuss a major problem with the studies, so that those interested in replication can avoid the same error.
Analysis of Ethnic Variations in Developmental Disability Prevalence and Household Economic Status

Prevalence of developmental disabilities among the three largest U.S. racial and ethnic groups was estimated. Groups were compared on household economic status and access to welfare programs. Secondary analyses were conducted on 1990 and 1991 panels of the Survey of Income and Program Participation, a nationally representative data base of the demographic and economic status of U.S. households. Estimated prevalence rate was 1.1% (June through December 1991), with the highest rate (1.4%) among Blacks. Households with a family member with developmental disabilities had significantly lower income and greater dependence on means-tested income support. Minority status exacerbated differences in earned income and access to welfare. Results were discussed in the context of general U.S. demographic trends.
Ectopic activation of torpedo/Egfr, a Drosophila receptor tyrosine kinase, dorsalizes both the eggshell and the embryo

The Drosophila gene torpedo/Egfr (top/Egfr) encodes a homolog of the vertebrate Epidermal Growth Factor receptor. This receptor is required several times during the life cycle of the fly for the transmisson of developmental cues. During oogenesis, Top/Egfr activation is required for the establishment of the dorsal/ventral axis of the egg and the embryo. To examine how ectopic Top/Egfr activation affects cell fate determination, we constructed an activated version of the protein. Expression of this activated form (lambda top) in the follicle cells of the ovary induces dorsal cell fates in both the follicular epithelium and the embryo. Different levels of expression resulted in different dorsal follicle cell fates. These dorsal cell fates were expanded in the anterior, but not the posterior, of the egg, even in cases where all the follicle cells covering the oocyte expressed lambda top. The expression of genes known to respond to top/Egfr activation, argos (aos), kekkon1 (kek 1) and rhomboid (rho), was also expanded in the presence of the lambda top construct. When lambda top was expressed in all the follicle cells covering the oocyte, kek 1 and argos expression was induced in follicle cells all along the anterior/posterior axis of the egg chamber. In contrast, rho RNA expression was only activated in the anterior of the egg chamber. These data indicate that the response to Top/Egfr signaling is regulated by an anterior/posterior prepattern in the follicle cells. Expression of lambda top in the entire follicular epithelium resulted in an embryo dorsalized along the entire anterior/posterior axis. Expression of lambda top in anterior or posterior subpopulations of follicle cells resulted in regionally autonomous dorsalization of the embryos. This result indicates that subpopulations of follicle cells along the anterior/posterior axis can respond to Top/Egfr activation independently of one another.
HACCP development and regulatory assessment in the United States of America

Hazard Analysis Critical Control Point (HACCP) is internationally recognized as the best method of assuring product safety by controlling foodborne safety hazards. Currently, within the USA, the FDA has mandated HACCP for fish and fishery products and is proposing mandating HACCP for fruit and vegetable juices. The USDA has mandated Pathogen Reduction/HACCP requirements for meat and poultry processing, and the NMFS Seafood Inspection Program operates a voluntary HACCP program for seafood plants. The requirements for mandatory implementation and proposed regulations represent a significant change in the manner in which foods are regulated for food safety and necessitate a new understanding of the diAerent roles and responsibilities between the food industries and the regulatory agencies within the USA. Each agency will approach the evaluation process differently given their unique legislative authorities and programmatic operations. Nevertheless, each agency agrees that HACCP is the best food control system of choice and is committed to improve food safety requirements. ” 2000 Published by Elsevier Science Ltd. All rights reserved.
Internal waves of permanent form in fluids of great depth

This paper presents a general theoretical treatment of a new class of long stationary waves with finite amplitude. As the property in common amongst physical systems capable of manifesting these waves, the density of the (incompressible) fluid varies only within a layer whose thickness h is much smaller than the total depth, and it is h rather than the total depth that must be considered as the fundamental scale against which wave amplitude and length are to be measured. Internal-wave motions supported by the oceanic thermocline appear to be the most promising field of practical application for the theory, although applications to atmospheric studies are also a possibility.The waves in question differ in important respects from long waves of more familiar kinds, and in § 1 their character is discussed on the basis of a comparison with solitary-wave and cnoidal-wave theories on customary lines, such as apply to internal waves in fluids of limited depth. A summary of some simple experiments is included at the end of § 1. Then, in § 2, the comparatively easy example of two-fluid systems is examined, again to illustrate principles and to prepare the way for the main analysis in § 3. This proceeds to a second stage of approximation in powers of wave amplitude, and its leading result is an equation (3·51) determining, for arbitrary specifications of the density distribution, the form of the streamlines in the layer of heterogeneous fluid. Periodic solutions of this equation are obtained, and their properties are discussed with regard to the interpretation of internal bores and wave-resistance phenomena. Solutions representing solitary waves are then obtained in the form \[ f(x) = a\lambda^2/(x^2+\lambda^2), \] where xis the horizontal co-ordinate and where aΛ = O(h2). (The latter relation between wave amplitude and length scale contrasts with the customary one, aΛ2 = O(h3)). The main analysis is developed with particular reference to systems in which the heterogeneous layer lies on a rigid horizontal bottom below an infinite expanse of homogeneous fluid; but in § 4 ways are given to apply the results to various other systems, including ones in which the heterogeneous layer is uppermost and is bounded by a free surface. Finally, in §5, three specific examples are treated: the density variation with depth is taken, respectively, to have a discontinuous, an exponential and a ‘tanh’ profile.
Hormonal stimulation of the recovery of spermatogenesis following chemo- or radiotherapy

Radiation and chemotherapeutic drugs produce prolonged depression of sperm counts in rodents and humans. Previously, three approaches have been developed in experimental animals that have had some success in preventing or reversing this toxicity. These approaches included pretreatment with hormones that suppress spermatogenesis, stimulation of stem cell number, and supplementation with testosterone. A different rationale for the ability of particular hormonal treatments to reverse prolonged azoospermia is presented in this review. In many cases prolonged azoospermia occurs even though the stem spermatogonia survive the toxic insult, but the differentiation of these spermatogonia to produce sperm fails. In the rat, the block appears to be at the differentiation of the A spermatogonia. Hormone treatments with testosterone or with GnRH agonists, which suppress intratesticular testosterone levels, relieve this block and result in the production of differentiating cells. When the hormone treatment is stopped the production of differentiating cells continues, mature sperm are produced, and fertility is restored. If a similar mechanism can be demonstrated to hold in humans, the fertility of men who have been rendered infertile by treatments for testicular and other cancers could be improved.
Subsistence and Sustainability: From Micro-Level Behavioral Insights to Macro-Level Implications on Consumption, Conservation, and the Environment

The objective of this article is to develop micro-level behavioral insights at the intersection of poverty and the environment and derive macro-marketing implications. This micro-level behavioral perspective encompasses psychological and socio-cultural phenomena and emphasizes consumption and conservation. Construing the environment in a broad sense to encompass living circumstances, we conducted interviews to uncover the distinctive nature of environmental issues in subsistence marketplaces. Our findings emphasize the importance of different levels of spatial and psychological distance as well as a number of coping strategies that reflect individuals and communities sustaining themselves through survival, relatedness, and growth. We link distances and coping to efficacy and motivation to act, and derive implications for macro-level issues in marketing management, and public policy.
Qualitatively Different Memory CD8+ T Cells Are Generated after Lymphocytic Choriomeningitis Virus and Influenza Virus Infections

Viral infections often induce robust T cell responses that are long-lived and protective. However, it is unclear to what degree systemic versus mucosal infection influences the generation of effector and memory T cells. In this study, we characterized memory CD8(+) T cells generated after respiratory influenza virus infection and compared the phenotypic and functional qualities of these cells with memory T cells generated after systemic infection with lymphocytic choriomeningitis virus (LCMV). Using a recombinant influenza virus expressing the LCMV gp(33-41) epitope and TCR transgenic CD8(+) T cells with a fixed TCR, we compared responses to the same Ag delivered by mucosal or systemic viral infection. Memory cells generated postinfection with either virus showed only a few phenotypic differences. Yet, influenza memory T cells produced lower amounts of effector cytokines upon restimulation and displayed reduced proliferation compared with LCMV-induced memory cells. Strikingly, we observed reduced expansion of spleen- and, in particular, lung-derived influenza memory cells after recall in vivo, which correlated with reduced early protection from secondary infection. These findings suggest that qualitatively different memory CD8(+) T cells are generated after respiratory or systemic virus infections.
Post-transcriptional Down-regulation of ROCKI/Rho-kinase through an MEK-dependent Pathway Leads to Cytoskeleton Disruption in Ras-transformed Fibroblasts

Transformation by oncogenic Ras profoundly alters actin cytoskeleton organization. We investigated Ras-dependent signaling pathways involved in cytoskeleton disruption by transfecting normal rat kidney (NRK) cells with different Ras mutants. RasV12S35, a mutant known to activate specifically the Raf/MAPK pathway, led to stress fiber and focal contact disruption, whereas the adherens junctions remained intact. Next, we found that pharmacological inhibition of MEK was sufficient to restore the cytoskeletal defects of ras-transformed NRK cells, including assembly of stress fibers and focal contacts, but it did not induce reorganization of the cell-cell junctions. Investigating the mechanism underlying this phenotypic reversion, we found that the sustained MAPK signaling resulting from Ras-transformation down-regulated the expression of ROCKI and Rho-kinase, two-Rho effectors required for stress fiber formation, at the post-transcriptional level. On MEK inhibition, ROCKI/Rho-kinase expression and cofilin phosphorylation were increased, demonstrating that the Rho-kinase/LIM-kinase/cofilin pathway was functionally restored. Finally, using dominant negative or constitutively active mutants, we demonstrated that expression of ROCKI/Rho-kinase was both necessary and sufficient to promote cytoskeleton reorganization in NRK/ras cells. These findings further establish the Ras/MAPK pathway as the critical pathway involved in cytoskeleton disruption during Ras-transformation, and they suggest a new mechanism, involving alteration in ROCKI/Rho-kinase expression, by which oncogenic Ras can specifically target the actin-based cytoskeleton and achieve morphological transformation of the cells.
Fast and robust neural network based wheel bearing fault detection with optimal wavelet features

We propose a new design of a neural network based system to detect faulty bearings using acoustic signals in a noisy wayside environment. Statistical features are generated from discrete wavelet transform coefficients, and a genetic algorithm is used to select the optimal features. The false negative rate for detecting a condemnable bearing is as low as 0.1% regardless of the speed, load condition, and bearing type.
APPLICATION OF DISTRIBUTED PARAMETER CONTROL MODEL IN WILDLIFE DAMAGE MANAGEMENT

A bioeconomic model for optimal control of wildlife damage by migratory small mammal populations is developed under the framework of a nonlinear distributed parameter control problem. The model first simulates the spatio-temporal dynamics of dispersal population by parabolic diffusive Volterra-Lotka partial differential equation and then optimizes a criterion function of present value combined costs of wildlife damage and harvesting. The existence of a unique optimal solution for a finite time problem is proved. An iterative procedure for numerical solution of the Optimality System with parabolic equations of opposite orientations is developed. The theoretical model is applied to a real life problem using biological and economic data for beaver populations under certain simplistic assumptions.
Role of Colonic Motility in Guiding Therapy in Patients with Constipation

Constipation is a common condition defined by less than three bowel movements per week. Often constipation is secondary to altered motility of the colon. Tests that measure colonic motility lead the c
Acceptance of plate tectonic theory by geologists

How do scientific theories come to be accepted? What roles do age, education, type of employment, area of specialization, and familiarity with relevant literature play in the acceptance of theories? The present study was designed to provide preliminary answers to these questions with respect to the theory of plate tectonics and to give direction to a more extensive study of the acceptance of plate tectonic theory. A random sample of 128 Fellows of the Geological Society of America and 87 active members of the American Association of Petroleum Geologists was surveyed in mid-1977. We present the results of that survey and tentative generalizations based on the survey.
On the use of general elements in fluid dynamics simulations

As flow solvers have become more sophisticated, many now have the capability to handle meshes with general polyhedral elements, i.e. general elements. In response, researchers have begun to develop mesh generation strategies that exploit nonstandard element types. General elements have been employed locally in near-body extruded meshes to improve mesh quality and have also been used in solution adaptive mesh refinement algorithms. In this paper, we present two mesh generation strategies that employ general elements. We also discuss how a specific flow solver is formulated to work with general elements. We demonstrate our approach by presenting simulation results for two realistic configurations. We close with a discussion that highlights future research directions.
Frictional lag and stick-slip

Dimensional and perturbation analyses are applied to the problem of stick-slip encountered during the motion of machines with nonlinear low-velocity friction. The friction model studied incorporates kinetic, viscous and Stribeck friction with frictional lag. Through dimensional analysis an exact model of the nonlinear system can be formed in four parameters rather than nine, greatly facilitating study and explicitly revealing the interaction of parameters. By converting the system of differential equations into a set of integrations, the perturbation technique makes approximate analysis possible where only numerical techniques had been available before. The analysis predicts the onset of stick-slip as a function of plant and controller parameters. These results are compared with experimental data. >
Performance of a three-phase resonant DC link voltage source inverter using MCTs

The authors present and discuss experimental results on a voltage source resonant DC link (RDCL) power converter using the first commercially available MOS-controlled thyristor (MCT). The switching characteristics, the losses, the drive circuit requirement, and the possible failures of the MCT were assessed when the converter was driving a 5.0 hp induction motor. The performance of the MCT is compared with previously reported results using other power devices. The MCT did not show any noticeable turn-on or turn-off problems. A short tail was observed during turn-off. The power loss of the MCT is about 2.5% of the input power. The device has experienced failures at voltage and current levels well below its ratings. >
Value of bulk heat flux parameterizations for ocean SST prediction

Bulk heat flux parameterization is an increasingly popular technique for forcing non-coupled ocean models. If sea surface temperature (SST) from the model is colder (warmer) than observed, then the net heat flux will be higher (lower) than observed; thus, bulk parameterizations tend to keep model SST close to observational SST on long time scales. However, bulk parameterizations imply neither strong damping of SST variability nor strong relaxation to near-surface (e.g., at 10 m) air temperature (Ta). This is demonstrated using SST simulations from a 0.72°×0.72° cos(lat) (longitude×latitude) resolution global HYbrid Coordinate Ocean Model (HYCOM) that does not include assimilation of any SST data or explicit relaxation to any SSTclimatology, but does use bulk heat fluxes. Results are discussed when climatological wind and thermal atmospheric forcing for HYCOM are constructed from three different archived numerical weather prediction (NWP) products: (1) the European Centre for Medium-Range Weather Forecasts (ECMWF) 15-year Re-Analysis during 1979–1993 (ERA-15), (2) ECMWF 40-year Re-Analysis (ERA-40) during 1979–2002, and (3) the Common Ocean Reference Experiment Corrected Normal Year forcing version 1.0 (CORE-CNY) based on the National Centers for Environmental Prediction (NCEP) re-analysis which spans 1948–2002. To investigate the implications of the bulk heat flux approachasrelaxation to SSTandTa,HYCOMSSTsimulations areusedto demonstratethat modelSSTerrorswithrespecttothe NationalOceanicAtmosphericAdministration(NOAA)SSTclimatologydonotlooklikeTa −SSTfieldsfromNWPproducts.Sucha result is confirmed for all simulations forced with ERA-15, ERA-40 and CORE-CNY, separately. Overall, global averages of mean HYCOM SSTerror are 0.2 °C (1.5 °C), 0.4 °C (1.7 °C) and 0.6 °C (2.3 °C) with respect to NOAA SST (NWP Ta) climatology when the model uses atmospheric forcing from ERA-15, ERA-40 and CORE-CNY, respectively. © 2008 Elsevier B.V. All rights reserved.
Feedback instability of the ionospheric resonant cavity

A model is developed that provides a theoretical basis for previous numerical results showing a feedback instability with frequencies characteristic of Alfven travel times within the region of the large increase of Alfven speed above the ionosphere. These results have been extended to arbitrary ionospheric conductivity by developing a numerical solution of the cavity dispersion relation that involves Bessel functions of complex order and argument. It is concluded that the large contrast between the magnetospheric and ionospheric Alfven speed leads to the formation of resonant cavity modes with frequencies ranging from 0.1 to 1 Hz. The presence of the cavity leads to a modification of the reflection characteristics of Alfven waves with frequencies that compare to the cavity's normal modes.
Deformation, recrystallization, strength, and fracture of press-forged ceramic crystals.

Sapphire and ruby were very difficult to press-forge because they deformed without cracking only in a limited temperature range before they melted. Spinel crystals were somewhat easier and MgO, CaO, and TiC crystals much easier to forge. The degree of recrystallization that occurred during forging (which was related to the ease and type of slip intersections) varied from essentially zero in Al2O3 to complete (i.e., random polycrystalline bodies were produced) in CaO. Forging of bi- and polycrystalline bodies produced incoherent bodies as a result of grain-boundary sliding. Strengths of the forged crystals were comparable to those of dense polycrystalline bodies of similar grain size. However, forged and recrystallized CaO crystals were ductile at lower temperatures than dense hot-pressed CaO. This behavior is attributed to reduced grain-boundary impurities and porosity. Fracture origins could be located, indicating that fracture in the CaO occurs internally as a result of surface work hardening caused by machining.-
A Method for Combined C-Banding and Silver Staining

A reliable technique for combined C-banding and silver staining of metaphase chromosomes which uses trypsinization is described. Slides are first immersed in dilute HCl to remove residual cytoplasm from around the chromosomes. They are then treated with saturated barium hydroxide and incubated overnight in saline sodium citrate (0.30 M NaCl, 0.03 M sodium citrate, adjusted to pH 7.0 with HCl). Following the C-banding pretreatment, a two-step method of silver staining which employs a protective colloidal developer is used to stain the nucleolar organizer regions (NORs) of the chromosomes. Silver staining is followed by trypsinization to remove extraneous silver precipitate from the chromosome arms which permits the C-bands to be stained with Giemsa. The method works equally well with fresh and aged mitotic chromosome preparations and gives consistent staining of both heterochromatin and active NORs in metaphases across the slide.
Dynamic methylation driven by neuronal activity in hippocampal neurons impacts complex behavior

Epigenetic processes are well-known to play critical roles in learning and memory. Among epigenetic processes, accumulating data suggests that DNA methylation in particular is a critical determinant of learning and memory. In vitro data have suggested that DNA methyltransferase inhibitors can trigger DNA demethylation and subsequent gene expression of the brain-derived neurotrophic factor gene in an activity dependent manner. To examine if these processes occur in vivo, we chronically infused DNMT inhibitors into the hippocampus and examined the impact on behavior. We find that chronic DNMT inhibition in the hippocampus results in increased anxiety-related behavior and deficits in context-dependent fear conditioning accompanied by an increase in BDNF expression. Gene expression changes were blocked by pretreatment with the NMDA receptor antagonist AP5, suggesting that DNMT inhibition enhances gene expression in an activity-dependent manner and that, conversely, the behavior deficits and abnormal gene expression are facilitated by NMDA receptor activity. Open image in new window
Particles and Vector Bundles

This chapter deals with some specific vector bundles over the spacetime that serve as models of elementary particles. We restrict our consideration to particles of matter (as opposed to particles mediating interactions) which are free, i.e., not subject to interactions. The choice of the bundles to represent them is justified in Chapter 3. Analogous models of interaction carriers and interacting particles are described in Chapters 5 and 6.
O fardo holandês: escravidão, África e imigrantes nos livros de história da escola primária na Holanda

Ha muito, os holandeses se orgulham de sua identidade de povo tolerante, “terra prometida” para imigrantes perseguidos e generosa com fundos de “desenvolvimento” direcionados a outras nacoes. Esquivam-se, contudo, do papel que desempenharam historicamente no imperialismo, na escravatura e no genocidio colonialistas e consideram os nao brancos, tanto na Holanda quanto fora dela, ingratos para com a ajuda de seu pais. Esse artigo sintetiza pesquisas anteriores sobre as representacoes de escravidao, imigracao e da Africa em todos os livros didaticos de historia para ensino fundamental na Holanda publicados a partir de 1980, argumentando que estes apresentam metanarrativas eurocentricas de europeizacao racial no contexto unico da sociedade holandesa. Esses livros perpetuam o esquecimento social, pelos holandeses, da escravidao e do colonialismo cientifico, justificam intervencoes historicas e contemporâneas na Africa, essencializam e problematizam os imigrantes e suas culturas, destacam a superioridade holandesa e facilitam a ideia de um “fardo holandes”, que encontra a Holanda auxiliando, com relutância, minorias dentro e fora de suas fronteiras. Essas descobertas tem implicacoes importantes para o pais e para todas as nacoes com uma populacao crescente de imigrantes, pois os discursos e conhecimentos apresentados nos livros didaticos tem afetado geracoes sucessivas de estudantes, que formulam politicas locais e nacionais a respeito das minorias, identidades e ideologias raciais.