cssi/SciSciGPT-SciSciNet huggingface dataset:
Choice of Neuroimaging in Perioperative Acute Stroke Management

At the time of this publication, the fast examination time, wide availability, lack of contraindications, and high accuracy for detecting hemorrhage make NCCT the diagnostic study of choice for initial evaluation of patients who have preoperative stroke. NCCT also has a role in excluding patients who will not benefit from IV thrombolysis, including those who have ICH and patients who have ASPECTS less than 7 or ischemic signs exceeding one third of the MCA territory. Because optimal selection of inpatients who have acute stroke mandates not just brain tissue data but also information about the aortic arch, cervical and intracranial vasculature, and cerebral hemodynamics, additional imaging with multimodal CT technology can, in one scanning session, depicts early ischemic changes, demonstrates hypoperfusion/ischemic penumbra, and locates the vascular lesion. When combined with the clinical scenario, the information provided by CT often is sufficient to help clinicians decide on the appropriate treatment, especially determining eligibility for thrombolysis. The rapidly evolving field of neuroradiology will provide a newer armamentarium in the near future. Although MRI can provide more precise information, it is more time consuming and currently should be considered the method of choice for follow-up imaging, rather than initial imaging, in patients who have perioperative stroke.
Pitfalls in the surgical management of the incomplete duodenal diaphragm.

Abstract Twenty-one consecutive patients with incomplete duodenal diaphragms were treated without fatality. Observed and reported pitfalls for the surgeon include difficulty in diagnosis before and during laparotomy, coexistence with intestinal malrotation or intrinsic obstructions of the duodenum, stomach or anorectum, intimate anatomic relationship with the bile ducts, the confusing features of the windsock type diaphragm, and a tendency for malfunction of bypassing lateral anastomoses. Successful management has featured increased preoperative diagnostic effort, use of a Foley bag catheter or appropriate instrument to help locate and calibrate intrinsic obstructions, and a preference for excision of the diaphragm with protection of the bile ducts.
Physician-Controlled Wire-Guided Cannulation of the Minor Papilla

Background. Minor papilla (MiP) cannulation is frequently performed using specialized small-caliber accessories. Outcomes data for MiP cannulation with standard-sized accessories are lacking. Methods. This is a case series describing MiP cannulation outcomes in consecutive patients treated by two endoscopists between July 2005 and November 2008 at two tertiary referral centers. MiP cannulation was attempted using a 4.4 Fr tip sphincterotome loaded with a 0.035, 260 cm hydrophilic-tip guidewire, using a wire-guided technique under physician control. Results. 25 patients were identified (14 women, mean age 45). Procedure indications included recurrent acute pancreatitis in 16 patients (64%) and chronic pancreatitis in 2 (8%), among other indications. MiP cannulation was successful in 24 patients (96%). Sphincterotomy followed by pancreatic stent placement was performed in 21 patients (84%). Mild post-ERCP pancreatitis occurred in 3 patients (12%). Conclusion. Physician-controlled wire-guided MiP cannulation using a 4.4 Fr sphincterotome and 0.035 guidewire is an effective and safe technique.
The Influence of a Small Christian University's Culture on Selected Characteristics of Emerging Adulthood.

In the past 50 years researchers have identified a number of demographic shifts occurring within industrialized societies that have resulted in changes in the nature of the developmental processes occurring in young adults. Arnett (2000) labels this new, socially constructed time period, between the ages of 18 and 25 years, as emerging adulthood. His theory posits that culture plays a strong role in young peoples' transition to adulthood. The present study, modeled after Nelson (2003), was undertaken to explore the possible role that a university subculture may play in the process of the emergence of individuals into young adults. This study investigated the level of student involvement, subjective perceptions of adulthood status, religious identity, and behavioral activities of students attending a small Christian university located in Northern California. The results support the belief that the norms and values of a subculture may influence its members in ways that are different than the majority cultur...
Fate of DTPA, EDTA, and EDDS in Hydroponic Media and Effects on Plant Mineral Nutrition

ABSTRACT Synthetic chelators are commonly used in hydroponic media to solubilize iron (Fe); however, the fate of these chelators is unknown. This study examined the persistence of three synthetic chelators, ethylenediaminetetraacetate (EDTA), diethylenetriaminepentaacetate (DTPA), and ethylenediaminedisuccinate (EDDS) in a bench-scale lettuce production system. The EDDS concentration decreased rapidly within 7d, most likely due to biodegradation. The EDTA and DTPA concentrations stayed steady throughout the experiments despite additions to maintain a constant volume and loss of chelator may have been due to either plant uptake or photodegradation of the chelator. Despite large differences in solution chemistry, the final shoot concentrations of iron (Fe), manganese (Mn), copper (Cu), and zinc (Zn) were similar among chelator treatments, whereas root concentrations of these same elements were highly variable. The concentration of DTPA in a commercial lettuce production system was measured and highly variab...
Investigation of Signal Transduction through the HAMP Domain from Molecular Dynamics Simulations

The HAMP domain connects the extracellular sensory with intracellular signaling domains in over 7,500 proteins including histidine kinases, adenylyl cyclases, chemotaxis receptors, and phosphatases, and thus plays an essential role as a link in transmembrane signal transduction. Recently, Hulko et al. determined the solution NMR structure of the HAMP domain (PDB ID:2ASW) of an archaeal protein AF1503, a putative transmembrane receptor [Hulko, M., et al. (2006) Cell 126, 929-940]. Based on the NMR structure, we have modeled the relative orientation of transmembrane domains TM1 and TM2 using replica exchange molecular dynamics simulations (REXMD). We then performed MD simulations of the HAMP and TM complex in explicit lipid bilayers to investigate possible thermal motions as well as signal transduction mechanisms. In addition, as Hulko et al. suggested a signal transduction mechanism related to the canonical packing by rotation of the helices, we have investigated the helix rotation propensity through MD simulations. In this work, we will present the simulation results of the HAMP and TM complex as well as the HAMP domain alone.
Thermal insulation & condensation theory, tools & strategies

Abstract The increasingly high standards of thermal insulation have undoubted benefits in improving comfort, saving energy and avoiding the spread of mould growth on internal walls. The author, as a practising architect since the mid 1970s, is concerned with avoiding potential difficulties caused by using insulation in inappropriate ways. Since the advent of microcomputers in 1980, he has written software (Energy/1: Thermal Insulation & Condensation) as a tool to understanding and avoiding condensation problems, and applied these tools on behalf of other consultants, manufacturers, roofing contractors etc. as well as supplying the software for use by architects, manufacturers and local authorities etc. The purpose of this paper is to outline the theoretical bases for the current understanding of condensation, to describe the incorporation of that theory into the development of software and to describe available insulation strategies. [It is proposed that more detailed evaluations of roofs, walls & floors be described in further articles].
Analytical methodology for the determination of Kepone residues in fish, shellfish, and Hi-Vol air filters.

The recent discovery of the pollution of the environment with Kepone® has resulted in a tremendous interest in the development of residue methodology for the compound. Current multiresidue methods for the determination of the common organochlorinated pesticides do not yield good quantitative analytical results for Kepone. The extracting solvents are usually of insufficient polarity to extract Kepone from the various media. This article describes some of the recently developed methodology for Kepone in air filters, finfish, finfish livers and entrails, shellfish, and archival oyster samples.
Kinetic study on the nitrosation of dibenzylamine in a model system

A kinetic study of the formation of N-nitrosodibenzylamine (NDBzA), from the nitrosation of dibenzylamine (DBzA) by sodium nitrite, was performed in a model system under conditions (temperature, pH) that are similar to those encountered in the industrial production of hams processed in elastic rubber nettings. The nitrosation reaction was carried out in a KH2PO4 buffer (0.5 M) at pH 5.8 and at a temperature of 69 degrees C. Since DBzA is insoluble in an aqueous buffer system, a non-ionic surfactant, Tween 20, was used as a solubilizing agent. The nitrosation reaction exhibited first-order kinetics with respect to DBzA and second-order kinetics with respect to nitrite. The calculated rate constant was 4.7 +/- 0.5 M-2/min. The pH profile of NDBzA formation was also determined. The optimal pH of NDBzA formation, 3.12, was close to the pKa of nitrous acid (HNO2, pKa = 3.1).
Theories and analyses of thin and moderately thick laminated composite curved beams

Abstract A complete and consistent set of equations is derived for the analysis of laminated composite curved beams and closed rings. Equations are developed for thin and moderately thick curved beams. Rotary inertia and shear deformation as well as accurate kinematic relations are included in the moderately thick beam equations. Natural frequencies for simply-supported curved beams are obtained by exact solutions. Extension-bending coupling due to unsymmetric lamination is distinguished from that due to curvature. Effects of shear deformation, rotary inertia, curvature and thickness ratios, and material orthotropy on the natural frequencies are studied.
29Si NMR study of base‐catalyzed polymerization of dimethyldiethoxysilane

When moving from acidic to basic conditions for polycondensation of tetrafunctional alkoxysilanes, significant complications inhibit quantitative modeling of the polymerization process— most significantly formation of new liquid and solid phases. To understand what chemical processes influence the evolution of alkoxysilanes under basic conditions, we study the behavior of a model difunctional system which remains homogeneous during polycondensation and is of interest for preparing hybrid materials and elastomers. Characterizing the system by time-resolved 29Si NMR, we found direct quantitative evidence for three important differences in behavior from polymerization of alkoxysilanes under acidic conditions: (1) monomer consumption rate limited by hydrolysis rather than condensation; (2) a different substitution effect of siloxane connectivity on condensation reactivity; and (3) substantial reduction of the formation of small (six- or eight-atom) cycles. These results are consistent with the hypothesis of Chojnowski and coworkers that deprotonation of silanols destabilizes neighboring silicon–oxygen bonds. Additional chemistry, including deprotonation, siloxane solvolysis and disproportionation must be considered under alkaline conditions. Copyright © 1999 John Wiley & Sons, Ltd.
Hydrologic Regime Controls Soil Phosphorus Fluxes in Restoration and Undisturbed Wetlands

Many wetland restoration projects occur on former agricultural soils that have a history of disturbance and fertilization, making them prone to phosphorus (P) release upon flooding. To study the relationship between P release and hydrologic regime, we collected soil cores from three restoration wetlands and three undisturbed wetlands around Upper Klamath Lake in southern Oregon, U.S.A. Soil cores were subjected to one of three hydrologic regimes—flooded, moist, and dry—for 7.5 weeks, and P fluxes were measured upon reflooding. Soils from restoration wetlands released P upon reflooding regardless of the hydrologic regime, with the greatest releases coming from soils that had been flooded or dried. Undisturbed wetland soils released P only after drying. Patterns in P release can be explained by a combination of physical and biological processes, including the release of iron-bound P due to anoxia in the flooded treatment and the mineralization of organic P under aerobic conditions in the dry treatment. Higher rates of soil P release from restoration wetland soils, particularly under flooded conditions, were associated with higher total P concentrations compared with undisturbed wetland soils. We conclude that maintaining moist soil is the means to minimize P release from recently flooded wetland soils. Alternatively, prolonged flooding provides a means of liberating excess labile P from former agricultural soils while minimizing continued organic P mineralization and soil subsidence.
India, Africa, and the Second World War

(1986). India, Africa, and the Second World War. Ethnic and Racial Studies: Vol. 9, Ethnicity, Empire and Race Relations: Essays in Honour of Kenneth Kirkwood, pp. 306-320.
Direct measurement of the density of states of a two-dimensional electron gas

We present a direct measurement of the density of states of a two-dimensional electron gas in a quantizing magnetic field. By measuring the magnetocapacitance of modulation-doped GaAs-(AlGa) As heterostructures at low frequencies, we have observed quantum oscillations resulting from changes in the density of states alone.
The Potential of ‘Biodiesel’ from Oilseed Rape

This paper investigates the potential of biodiesel made from rapeseed oil as a transport fuel in the United Kingdom with respect to its economics, technology and environmental implications.
Bipedal Locomotion: Stopping and the Standing/Balance Gait

A bipedal locomotion system is synthesized to characterize some of the previously overlooked aspects of the locomotion process, specifically standing/balance and initiation and stopping. The locomotion system is described by a three-element three-dimensional model consisting of two lower limbs and an upper body. The system equations of motion are derived using variational methods, and are retained in their nonlinear form. The impulsive contact events of impact of the swing limb with the ground and transfer of support are incorporated into the model. Bipedal locomotion is synthesized through numerical simulations. Several control inputs are studied for establishing and sustaining the standing/balance gait. Subsequent motion is analyzed via phase-space portraits. It is shown that an impulsive torque is sufficient for establishing and controlling the standing/balance gait as well as steady locomotion.
Fluid electric force microscopy for charge density mapping in biological systems

Electric force microscopy has been adapted for mapping surface charge density in aqueous solutions. The electric double layer interaction between the tip and the sample provides a contrast mechanism sensitive only to the surface charge density as other parameters are held constant. The resulting charge maps are acquired at typical atomic force microscopy scanning rates and approximately 25-nm resolution. The contrast is well-described by a simple expression for the tip−sample double layer interaction in electrolyte solutions. Fluid electric force microscopy is highly sensitive and nondestructive, as demonstrated with charge density maps of fluid-phase-supported bilayer membranes and single DNA molecules.
Generalizability Theory and the Fair and Valid Assessment of Linguistic Minorities.

We discuss generalizability (G) theory and the fair and valid assessment of linguistic minorities, especially emergent bilinguals. G theory allows examination of the relationship between score variation and language variation (e.g., variation of proficiency across languages, language modes, and social contexts). Studies examining score variation across items administered in emergent bilinguals' first and second languages show that the interaction of student and the facets (sources of measurement error) item and language is an important source of score variation. Each item poses a unique set of linguistic challenges in each language, and each emergent bilingual individual has a unique set of strengths and weaknesses in each language. Based on these findings, G theory can inform the process of test construction in large-scale testing programmes and the development of testing models that ensure more valid and fair interpretations of test scores for linguistic minorities.
A medium-copy-number plasmid for insertional mutagenesis of Streptococcus mutans.

Abstract We have constructed a plasmid useful for insertional mutagenesis in Streptococcus mutans. The molecule, pSU20Erm, is based on a derivative of pACYC184 known as pSU20. The plasmid described here is approximately 3.7 kb in size and has the following properties: it replicates in Escherichia coli, does not replicate in S. mutans, contains an erythromycin-resistance marker which can be selected in E. coli or the streptococci, contains a multiple cloning site with few restriction sites in the remainder of the molecule, and can be screened on X-Gal-containing medium for the presence of insertions into the multiple cloning site. We have used the plasmid to construct a library of S. mutans DNA in E. coli and show that the clones can be reintegrated into the S. mutans chromosome via homologous recombination, thereby interrupting native genes. The plasmid has been used to clone part of a homologue of the E. coli drpA gene, encoding a global regulatory element for RNA synthesis. Further, we have identified an element closely linked to drpA in S. mutans with high homology to IS861.
Prostatic inflammation induces urinary frequency in adult mice.

Lower urinary tract symptoms (LUTS) including urinary frequency and nocturia are common in aging men. Recent studies have revealed a strong association of prostatic inflammation with LUTS. We developed an animal model of bacterial induced, isolated prostatic inflammation and examined the effect of prostatic inflammation on voiding behavior in adult C57BL/6J mice. Prostatic inflammation was induced by transurethral inoculation of uropathogenic E. coli—1677. Bacterial cystitis was prevented by continuous administration of nitrofurantoin. Hematoxylin and eosin (H&E) staining and bacterial culture were preformed to validate our animal model. Voiding behavior was examined by metabolic cage testing on post-instillation day 1 (PID 1), PID 4, PID 7 and PID 14 and both voiding frequency and volume per void were determined. Mice with prostatic inflammation showed significantly increased voiding frequency at PID 1, 7 and 14, and decreased volume per void at all time points, as compared to mice instilled with saline and receiving nitrofurantoin (NTF). Linked analysis of voiding frequency and voided volumes revealed an overwhelming preponderance of high frequency, low volume voiding in mice with prostatic inflammation. These observations suggest that prostatic inflammation may be causal for symptoms of urinary frequency and nocturia.
Reflection of Alfven waves from boundaries with different conductivities

The reflection of Alfven waves from the ionosphere plays a crucial role because the reflected wave can reduce or enhance the electric field pattern of the incident wave. The ionosphere is typically treated as a conducting surface, which has a height integrated Pederson conductivity. This approximation is appropriate in considering the reflection of Alfven waves because the wavelengths along the magnetic field are large compared to the height of the ionosphere. Shear Alfven wave reflection experiments have been performed in the large plasma device [W. Gekelman, H. Pfister, Z. Lucky, J. Bamber, D. Leneman, and J. Maggs, Rev. of Sci. Instrum. 62, 2875 (1991)] at the University of California, Los Angeles. A single frequency wave is launched from an antenna and reflects from a large plate inserted into the plasma column. By alternatively using a conducting and an insulating plate, the two extremes of conductivity relative to the Alfven conductivity, 1∕(μovA) are tested. The data are compared with the expected ...
Surgical treatment of the thumb in the rubinstein-taybi syndrome

In a review of 530 individuals with Rubinstein-Taybi syndrome, 182 (34%) were found to have thumbs in severe radial angulation ("hitch-hiker thumbs"), which prevented opposition and functional gripping strength. Surgery has been performed on 35 thumbs (from 20 patients), usually to correct a delta phalanx deformity. The preferred approach was a closing wedge osteotomy, with a Z-plasty on the concave side to straighten the thumb. In eight and possibly 11 of the 35 thumbs, the angulation deformity or stiffness recurred, emphasizing the importance of proper and careful surgery. We conclude that surgical correction of the deformity is best done before the age of two, so that the thumb is functional during the initial development of hand-eye coordination. Deviation persisting at the age of ten can be corrected by fusing the metacarpophalangeal joint.
Donepezil causes acute increases in regional cerebral blood flow in normal rat

associated to aging and AD. (Kalpouzos 2009, Mosconi, 2007). We focused on the small primate (Microcebus murinus (M.m.), during aging some animals develop cognitive impairments (Picq, 2007), amyloid plaque depositions, and altered Tau protein accumulation associated with cerebral atrophy (Kraska, 2009). Brain atrophy is predictive of cognitive alterations (Picq, 2010). The aim of the current study was to evaluate age-associated evolution of glucose uptake in M.m. by using non-invasive FDG PET. Methods: SeventeenM.m. (1.5 to 9 years) were evaluated by PET with MicroPET Focus220 system (FDG: 900mCurie/100g, i.v.) and 3D-MR images were recorded (PharmaScan Bruker 7T). M.m were anesthetized by isoflurane duringimages acquisition. MR and PET images were co-registered by rigid transformations to define volumes of interest (VOI) in brain and appraise Standard UptakeValues (SUV) as well as relative values as compared to whole brain. Results: MR images didn’t reveal any severe atrophy this study is focused on normal aging. PET study revealed a relationship between age and SUVs in the frontal cortex, the cerebellum, and in the whole brain. However, relative values were not correlated with age. The cohort was split by theM.m.midlife (4.5 years) in two groups, young (1.960.2 years) and old animals (6.460.5 years).This second analyse showed a difference between young and old animals in thewhole brain, frontal cortex and cerebellum (t-test).Conclusions:Anage-associated evolution of glucose uptake as measured by SUVs could bedetected in non-severely atrophied M.m. and resembles evolution of the regionalcerebral metabolic rates for glucose (rCMRGlc) observed in healthy aged humans.This study is a first step toward the characterization of age-associated changesof brain glucose uptake inM.m. and will be useful to understand brain aging inM.m.
Influence of Atmospheric Gases on the Electrical Properties of PbSe Quantum-Dot Films

We report the effects of N2 and O2 on the electrical properties of PbSe quantum-dot (QD) films treated with 1,2-ethanedithiol (EDT) by measuring the changes in the current−voltage characteristics of QD field-effect transistors (FETs). EDT-treated PbSe QD films at a base pressure of ∼10−5 Torr exhibit ambipolar transport. Exposing these films to N2 shifts the transfer characteristics toward negative gate-voltage values and increases the electron mobility. These changes could be reversed entirely by removing the N2 gas over the FET and returning to base pressure. Oxygen exposure shifts the transfer characteristics in the opposite direction toward positive gate-voltage values. Moreover, oxygen exposure reduces charge mobility but increases film conductivity. For exposures up to ∼108 langmuir, these O2-induced changes could be reversed completely by removing the O2 gas over the sample and returning to base pressure. However, after ∼1010 langmuir of O2 exposure, the changes are irreversible. The QD films then ...
The U.S. Petroleum Pipeline Industry under Regulatory Constraint

The oil-pipeline industry is one of several that, historially, have been prime regulatory targets and, consequently, the target of considerable research on the apparent inefficiency of firms subject to rate-of-return regulation. The Averch and Johnson (A-J) test of this effect is applied for the first time to the oil-pipeline industry. The history of pipeline regulation is unique because the original-cost rate base is not regulated and because the maximum rates-of-return have not been reassessed since the 1940s. A model using the Cobb-Douglas production function produces results that are inconsistent with the A-J effect in that capital is not substituted for labor, possibly because the pipeline industry uses highly specialized labor. Other explanations could be that regulation has little effect on firm behavior or, more likely, that the difference is due to regulatory lag. Additional research is indicated to acquire enough less-aggregated data on the firm level. 31 references, 4 tables. (DCK)
Selected Research on Scientists and Engineers in Industry: A Review and Assessment

The article reports the author's opinions regarding research conducted on industrial engineers and scientists. The author focuses on research that investigates the professional roles occupied by sc...
Relative Concentrations of Proton MR Visible Neurochemicals in Gray and White Matter in Human Brain

The relative distributions of N-acetylaspartate (NAA) + N-acetylaspartylglutamate (NAAG), creatine + phosphocreatine (Cr/PCr), and choline (Cho) in the gray and white matter of human brain were determined by utilizing proton magnetic resonance spectroscopic imaging (SI). The SI data was processed using an automated spectroscopic image processing algorithm, and image segmentation was performed using a supervised technique. Linear regression analysis indicated that the NAA + NAAG (2.01 ppm) and Cr/PCr (3.02 ppm) peaks are greater in gray matter compared with white matter. The large intersubject variation observed in the Cho (3.20 ppm) resonance prevented the assessment of its regional distribution with confidence.
Optical concept generation for the Synchronous Earth Observatory Satellite

A series of optical systems is considered for the Synchronous Earth Observatory Satellite (SEOS) and classified by field coverage. As field angle increases, so does utility, but the penalty is increased complexity, size, and weight. All-reflective optical configurations are required by the wide spectral range requiremnt and the 1.5-meter diameter equivalent area aperture size. A series of telescope designs has been developed to confirm design viability, to eliminate physical/ mechanical interference, and to generate preliminary envelope and packaging data. The optical designs were carried to the modulation transfer function (MTF) level. The range of field angles investigated varied from a few arc-minutes square to more than 7 degrees x 3 degrees. The configurations and comparisons of utility, performance, size, and weight are discussed, and impacts on the mission and subsystems are considered.
Removing the entropy from the definition of entropy: clarifying the relationship between evolution, entropy, and the second law of thermodynamics

Misinterpretations of entropy and conflation with additional misunderstandings of the second law of thermodynamics are ubiquitous among scientists and non-scientists alike and have been used by creationists as the basis of unfounded arguments against evolutionary theory. Entropy is not disorder or chaos or complexity or progress towards those states. Entropy is a metric, a measure of the number of different ways that a set of objects can be arranged. Herein, we review the history of the concept of entropy from its conception by Clausius in 1867 to its more recent application to macroevolutionary theory. We provide teachable examples of (correctly defined) entropy that are appropriate for high school or introductory college level courses in biology and evolution. Finally, we discuss the association of these traditionally physics-related concepts to evolution. Clarification of the interactions between entropy, the second law of thermodynamics, and evolution has the potential for immediate benefit to both students and teachers.
Applying Social Learning Theory to the Observer Role in Simulation

Abstract Students are often assigned to the role of observer during simulation experiences. Educators may struggle with the best way to provide learning experiences for students participating in this role. This article describes how one Midwest community college utilizes the component processes of Bandura's observational learning as a foundation to design simulation experiences around the observer role. Utilizing the component processes of attention, retention, motivation, and motor reproduction to design simulation experiences provides all participants, regardless of the role, the same opportunities to achieve scenario learning objectives. Short videos illustrating these concepts are included and examples of activities for each component of observational learning are provided. Recommendations for future research related to the role of observer are shared.
Slurry abrasion of polymers under simulated submarine conditions

Abstract A submarine power cable to link the Hawaiian islands is being considered. It will be longer and go deeper than any previously deployed power cable and presents a significant technology extension. It is anticipated that failure by abrasion due to rubbing against submarine rocks could be a distinct hazard. The present study was initiated to gain relevant data on the behavior of some candidate commercial polymers when abraded by typical submarine rock particles. Samples of high density polyethylene, polypropylene, poly(vinyl chloride), poly(methyl methacrylate), Delrin and polytetrafluoroethylene were abraded by slurries of crushed submarine rocks (pillow lava and coral). Comparison tests were made with slurries of quartz abrasives and with a pin-on-disk apparatus using SiC sandpaper. It was found that the various polymers tested showed the same general ranking independent of the abrasive used, even though the rates of wear varied by several orders of magnitude between the different tests and even though there was a distinct change in wear mechanism from almost pure surface fatigue to almost pure cutting from one end of the spectrum to the other. The results do not directly fit any of the existing models for abrasive wear and the need for a refined model is discussed.
Should Y stay or should Y go: The evolution of non-recombining sex chromosomes

Gradual degradation seems inevitable for non-recombining sex chromosomes. This has been supported by the observation of degenerated non-recombining sex chromosomes in a variety of species. The human Y chromosome has also degenerated significantly during its evolution, and theories have been advanced that the Y chromosome could disappear within the next ~5 million years, if the degeneration rate it has experienced continues. However, recent studies suggest that this is unlikely. Conservative evolutionary forces such as strong purifying selection and intrachromosomal repair through gene conversion balance the degeneration tendency of the Y chromosome and maintain its integrity after an initial period of faster degeneration. We discuss the evidence both for and against the extinction of the Y chromosome. We also discuss potential insights gained on the evolution of sex-determining chromosomes by studying simpler sex-determining chromosomal regions of unicellular and multicellular microorganisms.
Influence of body condition and forage type on prevalence of Escherichia coli O157:H7 and Salmonella in grazing beef cows

Aim: To determine the influence of body condition (BC) and forage type on the prevalence of faecal shedding of Escherichia coli O157:H7 and Salmonella from beef cows. Methods and Results: Thin or moderately conditioned cows (n = 115) were randomly assigned to graze either common bermudagrass (n = 3 pastures) or toxic endophyte-infected tall fescue (n = 3 pastures) for 62 days. Faecal samples were collected on day 0, 30 and 62. Overall percentage of faecal samples positive for E. coli O157:H7 was 2·6% and 2·0% for Salmonella. Percentage of cows positive for both E. coli O157:H7 and Salmonella on at least one occasion was 6·1%. BC, forage type or the interaction did not influence the prevalence of E. coli O157:H7 or Salmonella in the faeces of cows. Conclusions: BC at initiation of the grazing period or loss of BC in moderate conditioned cows during the grazing period did not influence faecal shedding of E. coli O157:H7 or Salmonella. Consumption of either forage type did not influence faecal shedding of either E. coli O157:H7 or Salmonella in beef cows of thin or moderate BC. Significance and Impact of the Study: Change in BC that typically occurs during the normal production cycle in grazing cows did not influence faecal shedding of pathogenic bacteria regardless of forage type.
Design and perceptibility of a wearable haptic device using low-frequency stimulations on the forearm

Upper-limb prosthetics lack the afferent feedback necessary for an amputee to know where the prosthesis is in relation to the rest of the body. To address this problem, haptic feedback devices have been explored. In this work, a prototype device, consisting of five modules, has been developed which has the capability to create touch stimulations on the forearm. Each module of the device is light-weight and compact (7.6 g, 25 × 25 × 11.5 mm) consisting of a wire coil spooled on a non-ferrous core and a neodymium magnet housed in a plastic component which can connect to the other components with Velcro. When a coil is energized, the magnet pushes against the skin creating tactile stimulation normal to the skin. In an experiment with five participants, 20 trials of individual stimulations and 20 trials of pattern stimulations were performed on each participant. Participants reported 86% accuracy in correctly locating a single stimulus and 97% accuracy in distinguishing between the four stimulation patterns.
Galileo NIMS Near-Infrared Observations of Jupiter's Ring System

We present the first observations of the Jovian ring system viewed at near-infrared wavelengths in forward-scattered light.
What Makes Negative Frames Resonant? Hamas and the Appeal of Opposition to the Peace Process

Increasingly, scholars are applying Social Movement Theory to explore how radical Islamist groups strategically employ framing to legitimize the use of violence. What has not been explicitly examined, however, is under what conditions radical frames are more resonant with the public than more moderate alternatives. This article argues that the strength of a particular frame depends on the credibility of the competing claim-makers. Drawing on public opinion polls from the Palestinian Territories, the article shows that the resonance of Hamas’ frames vis-a-vis the peace process between 1993 and 2006 depended on the ability of the Palestinian leadership to maintain its legitimacy. Since the Gaza take-over and Hamas’ shift to a position of leadership rather than opposition party, the organization's inability to deliver in the economic realm or to even feign any progress regarding the peace process damaged its credibility and reputation. Accordingly, its frames vis-a-vis the peace process also started losing t...
Growth, Technology, and the Demand for Scientists and Engineers

This study decomposes changes in science and engineering employment into their growth and technological change components, using an input-output approach. The analysis is based on highly disaggregated industy-occupation employment data and reveals that approximately 30 per cent of the change in total science and engineering employment can be attributed to technological change. This contrasts with the 54 per cent figure found in earlier research. The difference in these findings is due to the highly aggregated data employed in the earlier research.
Impact of natural gas fuel composition on criteria, toxic, and particle emissions from transit buses equipped with lean burn and stoichiometric engines

Abstract This study investigated the impacts of varying natural gas composition on the exhaust emissions from different technology transit buses. For this study, two CNG (compressed natural gas) buses equipped with lean burn combustion and OCs (oxidation catalysts), and one stoichiometric CNG bus equipped with a TWC (three-way catalyst) and EGR (exhaust gas recirculation) were tested on a chassis dynamometer over the CBD (Central Business District) cycle on six different gas blends each. The gases represented a range of compositions from gases with high levels of methane and correspondingly lower energy contents/WN (Wobbe number) to gases with higher levels of heavier hydrocarbons and correspondingly higher energy contents/WN. For the lean burn buses, gases with low methane contents exhibited higher NOx (nitrogen oxides) (19%–53%) and NMHC (non-methane hydrocarbon) (39%–102%) emissions, but lower emissions of THC (total hydrocarbon) (9%–24%), CH4 (methane) (23%–33%), and formaldehyde emissions (14%–45%). The stoichiometric engine bus with a TWC showed significantly reduced NOx and THC emissions compared to the lean burn buses, but did show higher levels of CO (carbon monoxide) and NH3 (ammonia). PM (particulate matter) mass emissions did not show any fuel effects, while PN (particle number) emissions exhibited some reductions for the higher WN gases.
Developmental regulation of gene expression in Tetrahymena.

Abstract The onset of gene expression in Tetrahymena thermophila during macronuclear differentiation was investigated by assay of galactokinase in conjugating deoxygalactose-resistant heterokaryons. Our results distinguish three successive states of galactokinase gene expression for cells developing a new macronucleus: stage 0, refractory to induction; stage 1, inducible by refeeding; and stage 2, induced. The refractory period ends at 12 to 13 hr after the onset of conjugation; this corresponds to the time of pair separation, and occurs several hours after the new macronuclei have become morphologically distinguishable. Stage 1 cells behave indistinguishably from mature starved cells. Inhibitor studies suggest (a) that galactokinase synthesis is induced coincidentally with the induction of bulk protein synthesis during conjugation: thus it behaves developmentally like a typical protein; and (b) that galactokinase mRNA is probably transcribed within 1 hr prior to its translation. Thus, when conjugating cells are refed during the refractory period, some developmental condition prevents the swift induction of protein (and galactokinase) synthesis observed upon refeeding starved (nonmating) cells. The possible nature of this developmental phenomenon is discussed.
The immunological meaning of Thy-1-negative NK cells.

In this article Donald Rowley and Prakash Shah propose that Thy-1(-) natural killer (NK) cells activated during the course of immune reactions suppress or eliminate dendritic cells (DC) which have interacted with antigen and are required to stimulate lymphocyte proliferation. They review the experimental basis for this concept of immune regulation and emphasize that nearly homogeneous populations of well-characterized NK cells are required to define the functions of NK cells.
Surfactant-assisted UV-photolysis of nitroarenes.

Photochemical transformations (k ¼ 254 nm) of 2,4-dinitrotoluene (2,4-DNT) in aqueous solutions containing the cationic surfactant cetyltrimethylammonium (CTA) and the anionic nucleophile borohydride (BH � ) were investigated. The overall decay rate was enhanced at CTA concentrations above the critical micelle concentration (cmc) when stoichiometric excess BHwas present in solution. A kinetic model that separates the overall reaction rate into micellar and aqueous pseudo-phase components indicates transformation in micelles is 17 times faster that in the homoge- neous water phase under those conditions investigated. Intermediate products were identified by comparing the HPLC retention times and ultraviolet-visible absorption spectra of product peaks to those of analytical standards. 2-Methyl-5- nitroaniline, 4-nitrotoluene, 2-nitrotoluene, 4-methyl-3-nitroaniline, 2,4-diaminotoluene, o-toluidine, 1,3-dinitrobenzene, 3-nitroaniline, p-cresol, and 2,4-diaminophenol were identified as photo-transformation intermediates or prod- ucts. 2002 Elsevier Science Ltd. All rights reserved.
Teaching Geographic Information Systems in a Problem-Based Learning Environment

How, where and why GIS is taught has been debated heavily in the geography literature. This article is a contribution to that debate, because it offers a new perspective from which to teach GIS: problem-based learning. In a problem-based learning classroom, theoretical foundations and the real world of problems are understood as constitutive of one another, rather than theory being prioritised over the real world of experience. In this paper, the author describes an introductory-level GIS class in which GIS was taught with a problem-based learning pedagogy. The problem around which the class focused was a proposal to add a new school district in the San Antonio, Texas metropolitan region. This article describes the class, including the nature of the problem and the way GIS skills were sequentially taught and integrated into the analysis of that problem.
Counseling couples in conflict about infertility: Issues and treatment

This article focuses on a set of disagreements that a couple experienced while pursuing infertility treatment. Aspects of conflict that are unique to this case and others that are common to most cases involving infertility are discussed. The thrust of the article is that conflict is an inevitable aspect of infertility, rather than the symptom of a troubled marriage. A therapist must understand the situational factors contributing to the conflict and help the couple learn to resolve it. Intervention procedures are noted that can help ameliorate infertility-related conflict. © 1996 John Wiley & Sons, Inc.
Renal hemodynamics in canine DOCA-salt hypertension: effect of calcium channel blockade.

Systemic arterial blood pressure (BP), renal blood flow (RBF), and renal vascular resistance (RVR) were followed for 3-4 wks during the progression of DOCA-salt hypertension in the conscious dog. Accompanying the gradual increase in BP was an increase in RBF; however, RVR was unchanged. The hypertension was totally reversed 5-7 days after cessation of DOCA-salt treatment, but the increase in RBF persisted, presumably as a result of renal hypertrophy. Renal adrenoceptor blockade with prazosin (6 dogs) and prazosin plus idazoxan (4 dogs) caused a comparable decrease in BP in the normotensive and DOCA-salt hypertensive dog; however, RVR was decreased only in the normotensive. Similar results were obtained during ganglionic blockade with hexamethonium. The i.v. infusion of diltiazem for 1 wk restored BP of the hypertensive dog to a normotensive level, and hexamethonium given i.v. had little further effect on either BP or RVR. These results suggest a non-neurogenically mediated mechanism of canine DOCA-salt hypertension that is susceptible to calcium channel blockade.
Nature of ferroelectric–paraelectric transition

Ferroelectric (FE) materials directly convert electrical energy to mechanical energy and are critical to applications such as sensors, transducers, and actuators. The giant electromechanical response is the manifestation of the critical point between the first-order and second-order ferroelectric–paraelectric (FE–PE) transitions. For the simple classic FE lead titanate (PbTiO3), it is commonly accepted that there is a critical point in the temperature–pressure phase diagram separating the first- and second-order FE–PE transitions at zero electric field. Here, we show that the FE-PE transition in PbTiO3 is second-order at zero electric field. We introduce the concept of the invariant critical points (ICP) among three phases, representing the stability of the PE phase with respect to two FE phases in a three-dimensional electric field-pressure-temperature phase diagram of PbTiO3. It is pointed out that the electromechanical response near ICPs is larger than that near the line of critical end points (LCEPs) ...
The road to modularity

A network of interactions is called modular if it is subdivided into relatively autonomous, internally highly connected components. Modularity has emerged as a rallying point for research in developmental and evolutionary biology (and specifically evo-devo), as well as in molecular systems biology. Here we review the evidence for modularity and models about its origin. Although there is an emerging agreement that organisms have a modular organization, the main open problem is the question of whether modules arise through the action of natural selection or because of biased mutational mechanisms.
Optimum geometries and relative energies for cytosine, thymine, uracil, the imino tautomer of cytosine, the enol tautomer of thymine, and the enol tautomer of uracil by the MINDO/2 SCF MO method

A MINDO/2 SCF MO geometry optimization of cytosine (C), thymine (T), uracil (U), the imino tautomer of cytosine (C*), the enol tautomer of thymine (T*), and the enol tautomer of uracil (U*)was made. The optimized geometries for cytosine, thymine, and uracil agree well with crystallographic data. The optimized geometries for the tautomers show the correct trends in bond lengthening and bond angle except for the C4—O4 length and C4—O4—H angle of T* and U*. The energies of tautomerization were found to be 10.3, −9.0, and −14.2 kcal/mol for C⇌C*, T⇌T*, and U⇌U*, respectively, when optimized geometries are used. The overestimation of the C4—O4—H angle is speculated to arise because of an inadequacy in the parametrization of the one-center integrals in MINDO/2.
Derivations and Dirichlet forms on fractals

Abstract We study derivations and Fredholm modules on metric spaces with a local regular conservative Dirichlet form. In particular, on finitely ramified fractals, we show that there is a non-trivial Fredholm module if and only if the fractal is not a tree (i.e. not simply connected). This result relates Fredholm modules and topology, refines and improves known results on p.c.f. fractals. We also discuss weakly summable Fredholm modules and the Dixmier trace in the cases of some finitely and infinitely ramified fractals (including non-self-similar fractals) if the so-called spectral dimension is less than 2. In the finitely ramified self-similar case we relate the p -summability question with estimates of the Lyapunov exponents for harmonic functions and the behavior of the pressure function.