cssi/SciSciGPT-SciSciNet huggingface dataset:
Entrainment, displacement and transport of tracer gravels

The mass and size distribution of grain entrainment per unit bed area may be measured by replacing a volume of the bed with tracer gravels and observing the mass difference before and after a transport event. This measure of spatial entrainment is relevant to any process involving size-selective exchange of sediment between transport and bed and may be directly used in calculations of sediment transport rate using an elementary relation for fractional transport components presented here. This relation provides a basis for evaluating tracer data collected by different methods and may be used to provide physical insight regarding the expected behaviour of tracer grains. The variation with grain size of total displacement length L ti depends on the degree of mobilization of the individual fractions on the bed surface: L ti is independent of D i for smaller, fully mobile sizes and decreases rapidly with D i for larger fractions in a state of partial transport (in which a portion of the surface grains remain immobile through the flow event). The boundary between fully and partially mobile grain sizes increases with flow strength. These inferences are supported by values of L ti calculated from flume experiments and provide a physical explanation for a summary relation between L ti and D i based on field data. © 1997 John Wiley & Sons, Ltd.
Fabrication, testing, and performance of a variable-focus x-ray compound lens.

Design, fabrication, testing, and performance of an x-ray lens assembly are described. The assembly consists of a number of precisely stacked and aligned parts, each of which is a section of an extruded aluminum piece having 16 parabolic cavities. The wall thickness between adjacent cavities is 0.2 mm. By stacking a number of long, extruded parts and cutting the assembly diagonally, a variable-focus lens system is derived. Moving the lens horizontally allows the incident beam to pass through fewer or more cavities focusing the emerging beam at any desired distance from the lens. The variable focus aluminum lens has been used at the Advanced Photon Source to collimate a monochromatic, 8 keV undulator beam. Results indicate collimation consistent with theoretical expectations.
Visualization of Charge Carrier Motion in Semiconductor Nanowires with Ultrafast Pump-Probe Microscopy

Femtosecond pump-probe microscopy is used to directly visualize the diffusion of photogenerated charge carriers in undoped silicon nanowires, as well as charge separation in a nanowire encoded with an axial p-type/intrinsic/n-type (p-i-n) junction.
Stagnation in accounting education research

Abstract A number of prominent scholars have argued that research published in the top accounting journals has stagnated. As evidence of research stagnation, these authors note that much of the research published in the top accounting journals relates to a limited group of topics, uses similar research methods, and is based largely on the same underlying theories. We argue in this paper that the same concerns noted for accounting research in general are evident in accounting education research. A historical analysis of the literature shows that most published accounting education articles are not empirical, still relate to a few general topics, and ignore several issues that we believe are important to accounting education practice. Empirical articles generally rely on the survey research method, with relatively few studies using experimental (or even quasi-experimental) methods. In addition to providing evidence from the literature to show that accounting education research has stagnated, we offer some suggestions for overcoming this problem and for advancing the literature.
Catalytic Reaction Mechanism of Acetylcholinesterase Determined by Born-Oppenheimer ab initio QM/MM Molecular Dynamics Simulations

Acetylcholinesterase (AChE) is a remarkably efficient serine hydrolase responsible for the termination of impulse signaling at cholinergic synapses. By employing Born-Oppenheimer molecular dynamics simulations with a B3LYP/6-31G(d) QM/MM potential and the umbrella sampling method, we have characterized its complete catalytic reaction mechanism for hydrolyzing neurotransmitter acetylcholine (ACh) and determined its multistep free-energy reaction profiles for the first time. In both acylation and deacylation reaction stages, the first step involves the nucleophilic attack on the carbonyl carbon, with the triad His447 serving as the general base, and leads to a tetrahedral covalent intermediate stabilized by the oxyanion hole. From the intermediate to the product, the orientation of the His447 ring needs to be adjusted very slightly, and then, the proton transfers from His447 to the product, and the break of the scissile bond happens spontaneously. For the three-pronged oxyanion hole, it only makes two hydrogen bonds with the carbonyl oxygen at either the initial reactant or the final product state, but the third hydrogen bond is formed and stable at all transition and intermediate states during the catalytic process. At the intermediate state of the acylation reaction, a short and low-barrier hydrogen bond (LBHB) is found to be formed between two catalytic triad residues His447 and Glu334, and the spontaneous proton transfer between two residues has been observed. However, it is only about 1-2 kcal/mol stronger than the normal hydrogen bond. In comparison with previous theoretical investigations of the AChE catalytic mechanism, our current study clearly demonstrates the power and advantages of employing Born-Oppenheimer ab initio QM/MM MD simulations in characterizing enzyme reaction mechanisms.
Effects of Cloud Size and Cloud Particles on Satellite-Observed Reflected Brightness

Satellite observations allowed obtaining data on the visible brightness of cumulus clouds over South Park, Colorado, while aircraft observations were made in cloud to obtain the drop size distributions and liquid water content of the cloud. Attention is focused on evaluating the relationship between cloud brightness, horizontal dimension, and internal microphysical structure. A Monte Carlo cloud model for finite clouds was run using different distributions of drop sizes and numbers, while varying the cloud depth and width to determine how theory would predict what the satellite would view from its given location in space. Comparison of these results to the satellite observed reflectances is presented. Theoretical results are found to be in good agreement with observations. For clouds of optical thickness between 20 and 60, monitoring cloud brightness changes in clouds of uniform depth and variable width gives adequate information about a cloud's liquid water content. A cloud having a 10:1 width to depth ratio is almost reaching its maximum brightness for a specified optical thickness.
Simulation studies of a scintillating fiber tracker for the SDC detector

Abstract Six design options for a scintillating fiber inner tracker for the SDC detector operating at the Superconducting Super Collider (SSC) are simulated. Concentric cylindrical configurations of axial fiber superlayers, ranging from four to six in number, are considered. Tracks from events generated by Pythia 4.8 at rates up to ten times design luminosity are swum through the tracker. Algorithms for reconstructing tracks of physics interest with p T > 10 GeV/ c among a background of low p T tracks are described. The optimum configuration found permits level 1 triggering up to η = 2.3 at ten times design luminosity. Inclusion of additional stereo fibers in this configuration permits level 2 stereo reconstruction up to eight times design luminosity.
Diagnosing HIV dementia: A retrospective analysis

The purpose of this study was to determine the criteria by which the diagnosis of HIV dementia was made by providers in a public HIV outpatient clinic and hospital, and to evaluate the extent to which the providers' diagnosis confirmed or denied the presence of HIV dementia according to CDC recommendations. Retrospective chart analysis was conducted detailing symptomology, laboratory findings, and social characteristics of 103 HIV-infected patients from Nov 1, 1990 to Dec 31, 1993. Seventy-eight patients were evaluated by providers and given a preliminary HIV dementia diagnosis; 25 patients received no preliminary diagnosis. On follow-up, 39 were confirmed diagnosis while 64 patients received no follow-up (confirmatory) diagnosis. Inability to pay attention or remember details, memory deficit, motor weakness, and mild disorientation were all found to be significantly associated with being evaluated by a provider. Substance use was prevalent. Inconsistent manner in which HIV-demented patients were identified highlights the need for a standardized evaluation of signs and symptoms known to be associated with HIV dementia.
Early expression of smooth-pursuit eye movement abnormalities in children of schizophrenic parents.

ABSTRACT Disordered smooth-pursuit eye movements (SPEM) and, specifically, small anticipatory saccades that disrupt SPEM have been hypothesized to be a marker of genetic vulnerability to schizophrenia. This study compares SPEM in children of schizophrenic parents with normally developing control children to assess whether SPEM abnormalities are also present in a subset of at-risk children. Method With infrared oculography, SPEM was examined in 13 children of schizophrenic parents and 19 normally developing controls (aged 6 to 15 years). Measures of smooth-pursuit gain and root mean square error were used in addition to more specific measures of catch-up saccades and anticipatory saccades. Results Children of schizophrenic parents differed from normally developing controls on gain and root mean square error, but not on catch-up saccades. Small anticipatory saccades were significantly more frequent in the at-risk group. The percentage of total eye movements due to anticipatory saccades identified 54% of the at-risk group (compared with none of the control group) as performing more than two standard deviations above (worse than) the control mean. Conclusions The presence of increased anticipatory saccades is evidence for an oculomotor dysfunction that may be a phenotype of the genetic risk for schizophrenia, expressed years prior to the possible development of clinical illness.
STOCHASTIC DIFFERENTIAL EQUATIONS IN HILBERT SPACE

Abstract Existence and uniqueness theorems for stochastic evolution equations are developed in a Hilbert space context. The results are based on a blending of the theorems for evolution equations with stochastic integration for Hilbert space valued random processes. The results are applied to stochastically forced parabolic partial differential equations such as have arisen in heat transfer problems.
The role of the fusiform gyrus in successful encoding of face stimuli.

PET was used to measure regional cerebral blood flow (rCBF) while memorizing pictures of unfamiliar human faces presented one at a time (FaceMemory). Other conditions included: (1) FaceRepeat—memorization of four individual faces presented repeatedly; (2) FaceWatching—viewing passively single faces without overt memory demands; and (3) Scrambled—counting dots superimposed on pictures of scrambled faces. After each FaceMemory condition and after the final FaceWatching condition scan, recall was tested by measuring face recognition. Contrasting FaceMemory and Scrambled conditions revealed several temporal activations: right midfusiform and bilateral anterior fusiform gyri. Contrasting FaceWatching and Scrambled conditions showed bilateral activation in the temporal poles and in the anterior fusiform gyri. No hippocampal activation arose from any contrast. Region of interest analyses on the above areas showed correlations with performance: (1) only rCBF in the right midfusiform correlated positively with encoding during the FaceMemory and FaceWatching conditions; (2) in the right temporal polar cortex rCBF decreased during FaceMemory and correlated positively with performance, whereas rCBF increased during FaceWatching and correlated negatively with incidental performance; and (3) activity in the anterior fusiform gyri remained constant across the conditions of FaceMemory, FaceRepeat, FaceWatching, and Scrambled and was uncorrelated with performance. These data suggest an expanded mnemonic role for the right midfusiform in depth of processing/encoding of face information, temporal polar cortex in face perception and recognition, and anterior fusiform activity in featural visual feature processing.
Dual beam and transient infrared stimulated photoconductivity in hydrogenated amorphous silicon at 4.2 K

Abstract Dual beam photoconductivity with band gap bias light and superposed steps of 0.4 ≤ h ν ≤ 0.6 eV infrared light was measured in intrinsic and p-type hydrogenated amorphous silicon (a-Si:H) at 4.2 K. For tail state electrons, an absorption cross-section, A e = 1.8 × 10 −17 cm 2 , and a recombination volume, υ e = 1.6 × 10 −18 cm 3 , were obtained. For holes, A h = A e 3 and υ e ≈ υ h .
Dynamic X-ray diffraction study of an unsupported iron catalyst in Fischer-Tropsch synthesis

Abstract In situ , Dynamic X-Ray Diffraction (DXRD) has been used to correlate changes in bulk catalyst composition with Fischer-Tropsch activity over unsupported iron catalysts. It was found that the specific iron carbide phase formed was a function of particle size and temperature, with e′-Fe 2.2 C formed over ξ-Fe 2.5 C for smaller particle sizes and lower temperatures. While catalytic activity initially increased with the increase in carbide formation, deactivation was observed to be coincident with the e′ → ξ iron carbide transformation. This and subsequent hydrogen etching experiments indicate that the carbon formed from this transformation may act as nucleation sites for subsequent carbon deposition via the Boudouard reaction. All of the data obtained in this study are consistent with the competition model of Fischer-Tropsch synthesis, but while the carbide model does not appear to be a viable mechanism, the carbide itself may act as the catalyst.
HISTOPATHOLOGY Of EXPERIMENTAL BACTERIAL MENINGITIS IN RABBITS

Despite extensive use of the rabbit to study the pathophysiology of bacterial meningitis (BM) and pharmacokinetics of new antimicrobials, the histopathology of the disease in this model has not been delineated. In order to define these abnormalities, 20 NZ wh rabbits were inoculated intracisternally by a percutaneous technique with normal saline (Controls, N=6), S. pnemnoniae type III (Spn) (N=5 before {NV} and N=2 after (V) passage in mice) and H. inf. type b (HII8). Inocula wore 3.810 CFU, 4.310CFU and 8.410 CFU, respectively. The brain was removed from the skull within 10 min after death, fixed immediately in 10% formalin for 2 uks and sectioned coronally at 10 uniform levels from the frontal lobes to the brain stem. Sections were stained by H&E and graded blindly for severity of leptomeningitis (0=nl ← 5=severe) and the presence of parenchymal involvement (cerebritis, abscess formation, ventriculitis, vasculitis and choroid plexitis). 3/5 rabbits with HIIB and 5/7 with Spn demonstrated at least 1 parenchymal lesion. These were of mild degree with the exception of 1 rabbit (HIIB) who died at 24th. There was no consistent relationship between the degree of CSF pleocytosis, ↑ lac or (I and the severity of histopathologic changes observed.
Investigation of disulfonamide ligands derived from o-phenylenediamine and their Pb(II) complexes by electrospray ionization mass spectrometry

Lead is highly toxic and lead poisoning is a threat to human health, especially for children. Development of selective Pb chelates is necessary for its extraction, sensing and detoxification in environmental and biological systems.1 Numerous examples of coordination and extraction of Pb(II) by macrocycles have been reported.2–6 Ionizable chelates, which extract metals via ion exchange, offer potential advantages, such as versatility, synthetic ease, and favorable complexation-decomplexation kinetics. The recently reported disulfonamides, 1,7 2,7 and 3,1 are practical Pb(II) ion-exchange extractants that take advantage of the preference of Pb(II) in lower coordination numbers for irregular ‘hemidirected’ coordination geometries with a stereochemically active lone pair. These sulfonamides are very effective in Pb(II) extraction, even at micromolar levels, from water into 1,2-dichloroethane, and 3 in particular is very selective against Zn(II) and Cu(II).1,7 Electrospray ionization (ESI) is a soft ionization technique, and ESI-MS has been widely used to investigate non-covalent complexation, such as protein-protein interactions, enzyme-inhibitor complexes, nucleotides, drugs, and the formation of metal complexes.8,9 Although a number of cationic macrocycle–Pb complexes have been studied by ESI-MS,3–5,10 a method has not been established to investigate the neutral Pb complexes of ionizable chelators, such as disulfonamides, using MS. Recently, ESI-MS has been employed to measure stability constants for metal–crown ether complexes,11,12 to estimate relative stability of metal complexes,13,14 and to evaluate the binding selectivity of macrocycles.4 Therefore, ESI-MS could be potentially used to determine the stability of Pb–disulfonamide complexes, and a method based on ESI-MS could be eventually established for rapid screening of disulfonamide ligands for Pb complexation. Understanding the ionization mechanisms of these ligands and their Pb complexes involved in the ESI-MS processes is critical in order to achieve our long-term goal of developing MS methods for rapid detection of metal–complex formation. In this paper, we present an ESI-MS method for characterization of the disulfonamide ligands 1–4 and their Pb(II) complexes in both positive and negative modes.
Market quality and price discovery: Introduction of the E-mini energy futures

Abstract In mid-June 2002, the New York Mercantile Exchange (NYMEX) introduced E-mini futures contracts on natural gas and crude oil, a natural response to information technology developments and investor interest. The transition data allow examination of the effects of the new contracts on market quality and price discovery. Bid–ask spreads on the regular futures have been reduced significantly since introduction of the E-mini futures, showing improved market quality from competition effects. The E-mini market contributes more than 30% to the price discovery process, although it represents less than 1% of the volume of the regular futures with the same underlying. E-mini futures have several advantageous characteristics over regular futures, which should explain these significant results.
Advances in Reprogramming Somatic Cells to Induced Pluripotent Stem Cells

Traditionally, nuclear reprogramming of cells has been performed by transferring somatic cell nuclei into oocytes, by combining somatic and pluripotent cells together through cell fusion and through genetic integration of factors through somatic cell chromatin. All of these techniques changes gene expression which further leads to a change in cell fate. Here we discuss recent advances in generating induced pluripotent stem cells, different reprogramming methods and clinical applications of iPS cells. Viral vectors have been used to transfer transcription factors (Oct4, Sox2, c-myc, Klf4, and nanog) to induce reprogramming of mouse fibroblasts, neural stem cells, neural progenitor cells, keratinocytes, B lymphocytes and meningeal membrane cells towards pluripotency. Human fibroblasts, neural cells, blood and keratinocytes have also been reprogrammed towards pluripotency. In this review we have discussed the use of viral vectors for reprogramming both animal and human stem cells. Currently, many studies are also involved in finding alternatives to using viral vectors carrying transcription factors for reprogramming cells. These include using plasmid transfection, piggyback transposon system and piggyback transposon system combined with a non viral vector system. Applications of these techniques have been discussed in detail including its advantages and disadvantages. Finally, current clinical applications of induced pluripotent stem cells and its limitations have also been reviewed. Thus, this review is a summary of current research advances in reprogramming cells into induced pluripotent stem cells.
Area Control of the Face Fly Using Self-Applicating Devices

An experiment using self-applicating dust dispensers around mineral salt boxes in beef cattle pastures and in the exit chute of a dairy barn for control of face flies, Musca autumnalis DeGeer, was carried out on an area basis in southwest Virginia. An experiment was set up on a farm of approximately 2000 acres, which consisted of 23 separate pastures each containing 50 to 100 head of cattle. In 13 of the pastures, 5% malathion dust was used in the devices. In 8 of the other pastures, dust formulations of the following were used: Bayer 37344 (4- (methylthio) -3,5-xylyl methylcarbamate) (5%) ; fenthion (2%) ; coumaphos (5%); dimetilan (2%); and Drione dust (10.0% Butacide (α-[2- (2-butoxyethoxy) ethoxy]-4,5-methylenedioxy- 2-propyltoluene), 1.0% pyrethrins, 45.0% butoxypolypropylene glycol, 4.0% petroleum distillate, and 40.0% Dri-die® #67 (silicon dioxide plus ammonium silicofluoride to extent of 3% fluorine) by weight). Two pastures were untreated. Face fly counts were lower in all the treatments but no significant difference between treatments was detected. An overall summary of the area treatment by the self-applicating devices indicated that although complete control was not obtained, there was substantial reduction in the number of face flies per animal and considerable relief was noted.
Locus of a histidine-based, stable trifunctional, helix to helix collagen cross-link: stereospecific collagen structure of type I skin fibrils

The loci of the three amino acid residues that contribute their prosthetic groups to form the stable, nonreducible, trifunctional intermolecular cross-link histidinohydroxylysinonorleucine in skin collagen fibrils were identified. Two apparently homogeneous three-chained histidinohydroxylysinonorleucine cross-linked peptides were chromatographically isolated. They were obtained from a tryptic digest of denatured unreduced 6 M guanidine hydrochloride insoluble bovine skin collagen. Amino acid and sequence analyses demonstrated that the prosthetic groups of alpha 1(I)-chain Hyl-87, alpha 1(I)-chain Lys-16c, and alpha 2(I)-chain His-92 formed the cross-link. The latter results served to define the locus of the stable, nonreducible trifunctional moiety. Identical types of analyses were performed on the three-chained peptides isolated after bacterial collagenase digestion of the cross-linked tryptic peptides. This confirmed the initial identification and location of the three peptides linked by the cross-link. In addition, data reported here provide for a correction of the micromolecular structure for the alpha 2(I) chain. Stereochemical considerations concerning this trifunctional cross-link's specific locus indicate that the steric relationships between the alpha chains of skin and skeletal tissue collagens are fundamentally different and the intermolecular relationships in skin fibrils are specific for skin. The same molecular relationships also indicate that histidinohydroxylysinonorleucine links three molecules of collagen. The stereochemistry of cross-linking for skin collagen is in accordance with and explains the X-ray findings of a 65-nm periodicity found for this tissue [Stinson, R. H., & Sweeny, P. R. (1980) Biochim. Biophys. Acta 621, 158; Brodsky, B., Eikenberry, E. F., & Cassidy, K. (1980) Biochim. Biophys. Acta 621, 162].
An investigation of consumer evaluations of reference price discount claims

Abstract Utility, correspondent inference, and adaptation-level theories were used as bases for examining the effects of merchant-supplied reference prices on consumers' internal reference prices. Reference prices, along with two attribution theory-based contextual variables, consistency and distinctiveness, were manipulated in a 2×2×2 design. The results supported the role of merchant-supplied reference prices in influencing consumer perceptions, but failed to provide statistical support for the hypothesized effects of the contextual variables.
Endocrine Effects of Marijuana

In the 35 years since the active compound of marijuana, delta9-tetrahydrocannabinol, was isolated, the psychological and physiological impact of marijuana use has been actively investigated. Animal models have demonstrated that cannabinoid administration acutely alters multiple hormonal systems, including the suppression of the gonadal steroids, growth hormone, prolactin, and thyroid hormone and the activation of the hypothalamic-pituitary-adrenal axis. These effects are mediated by binding to the endogenous cannabinoid receptor in or near the hypothalamus. Despite these findings in animals, the effects in humans have been inconsistent, and discrepancies are likely due in part to the development of tolerance. The long-term consequences of marijuana use in humans on endocrine systems remain unclear.
Effect of one- and two-leg training on arm and two-leg maximum aerobic power.

The purpose of this study was to examine the effect of one- and two-leg training on arm and two-leg maximum aerobic power. Seven subjects cycle-trained both legs simultaneously for 30 min·day−1, 4 days·week−1 for 4 weeks. Nine subjects cycle-trained each leg 15 min·day−1, 4 days· week−1 for 4 weeks. Both groups trained at a heart rate equal to that measured at 75% of their two-leg maximum aerobic power. Thus, during each training session the groups performed 30 min of work at the same heart rate intensity. Five subjects served as a non-training control group. Arm and leg maximum oxygen uptake tests were conducted before and after training. Only two-leg training induced significant gains in arm aerobic power (P<0.0003), whereas both modes of training resulted in signifcant increases in two-leg aerobic power (P<0.0008). The data demonstrate that improvements in arm aerobic power were dependent on the quantity of leg muscle mass involved in the training, whereas gains in two-leg aerobic power occurred regardless of whether the legs were trained separately or simultaneously.
Process optimization of a thermoplastic polyimidesulphone

The detailed characterization of an experimental thermoplastic polyimidesulfane adhesive based on 3,3 prime-diaminodiphenylsulfone and 3,3 prime,4,4 prime-benzophenone tetracarboxylic dianhydride was studied. Model compounds were also examined. Thermal cyclization of the amide-acid to the imide was studied by a variety of techniques including DSC, TGA, MS, in situ diffuse reflectance-FTIR, and flow measurement. Characterizations were continued during the processing of adhesive tapes and the fabrication, bonding, and testing of lap shear specimens. Results provide fundamental insights into the role of cure chemistry, and the effects of residual solvent and volatile produces on processing and performance. These insights and the resulting chemical models should lead to more efficient processing cycles for these and other related thermoplastic adhesive systems.
Adenotonsillectomy in the morbidly obese child

Abstract Objective: The prevalence of obesity in the pediatric population has risen more than 20% in 25 years. Accordingly, surgical procedures on obese children have become more common. Adenotonsillectomy (AT) remains among the most frequently performed pediatric surgical procedures in the United States. Our objective was to determine if there is an increased complication rate in morbidly obese (MO) children undergoing AT and if elective pediatric intensive care unit (PICU) admission for observation is warranted. Methods: This retrospective study includes postoperative admissions to the PICU over a 4-year period at one hospital. Out of 957 adenotonsillectomies performed by one surgeon, 543 were admitted to the hospital. Fourteen MO children were identified. Using body mass index (BMI; weight in kg/m 2 ), as calculated for age appropriate categories, postoperative outcomes of AT in MO children (>95th percentile BMI) were determined. These 14 were electively admitted to the PICU for airway observation. The indication for surgery in these 14 children was obstructive sleep apnea. Ages ranged from 4 to 15 years. There were 11 males and 3 females. Results: Two patients required overnight bi-level positive airway pressure (BiPAP) for oxygen desaturation. One patient remained intubated for 10 days. Three patients required supplemental oxygen. Four of these admissions had preoperative polysomnograms (PSGs). Conclusions: Our study concluded that routine PICU admission was not warranted for most MO patients although several required supplemental oxygen, BiPAP, and one required intubation. These interventions can easily be administered in a surgical floor bed. In fact, these results imply that performing this surgical procedure in obese children is not as risky as many believe. Trends were noted for an increased need of airway interventions in children requiring preoperative BiPAP and in those with comorbidities. In this small population, sample AT was performed on the basis of history. This is to serve as a pilot review for a prospective study in which preoperative PSGs would be used to determine potential indicators for elective PICU admission.
Critical comparison of OII(732–733 nm), OI(630 nm), and N2(1PG) emissions in auroral rays

[1] All-sky spectral imagery has been used to study the altitude distribution of OII(732–733 nm), OI(630 nm), and N2(1PG) emissions in tall auroral rays appearing at the poleward edge of the auroral oval. The OII(732–733 nm) emission layer was consistently higher than the OI(630 nm) emission layer in these structures; the peak emission altitudes were estimated to be ∼380 km and ∼240 km, respectively. Neither the high absolute altitude of the OII(732–733 nm) peak nor its >100 km offset from the OI(630 nm) peak are consistent with published model results, which consider electron impact on atomic oxygen as the sole source of auroral O+(2P). The present results suggest that O+(2P) may also be excited directly from ambient ionospheric O+(4S) atoms. Other contributing factors may include a significant underestimation of the rate coefficients for O+(2P) quenching, or field-aligned up-flows of ionospheric O+.
Trillo Rates Exhibited by Professional Early Music Singers

Summary Trillo rates of nine professional early music singers were assessed from recordings made as they varied their repetition rate between slow and fast at the 25, 50, and 75% levels of their concert pitch ranges. Continuous trilli at all pitch levels formed two distinct clusters: slow trillo rates ranged from 2.0 to 6.9 Hz and fast extended from 7.5 to 12.4 Hz. Trillo rates did not differ as a function of singer's voice type, gender, age, experience, or location in the voice range.
Prehistoric landscape management in the Andean highlands: Raised field agriculture and its environmental impact

The terrain within the Lake Titicaca Basin in the Andean highlands of Peru and Bolivia is a highly human-modified landscape. Archaeological investigations document that massive landscape modifications were undertaken throughout prehistory in order to intensively cultivate marginal lands. The paper focuses on raised fields, large earthen platforms which prevent waterlogging and flooding, increase soil fertility, conserve moisture, insure nutrient production and recycling, and improve crop microclimates. The environmental implications of the construction of over 82,000 hectares of raised fields for local vegetation, microclimate, soils, sedimentation, and hydrology are examined. The reuse of raised field agricultural technology to solve some problems of current land management is also discussed.
Conventional Laparoscopic vs Robotic Training: Which is Better for Naive Users? A Randomized Prospective Crossover Study.

Objective Robotic training (RT) using the da Vinci skills simulator and conventional training (CT) using a laparoscopic “training box” are both used to augment operative skills in minimally invasive surgery. The current study tests the hypothesis that skill acquisition is more rapid using RT than using CT among naive learners. Design and Participants A total of 40 subjects without laparoscopic or robotic surgical experience were enrolled and randomized to begin with either RT or CT. Then, 2 specific RT tasks were reproduced for CT and repeated 5 times each with RT and CT. Time and quality indicators were measured quantitatively. A crossover technique was used to control for in-study experience bias. Results The tasks “pick and place jacks” (PP) and “thread the rings” (TR) were achieved faster with RT than with CT despite crossover (p Conclusions Speeds were faster overall with RT than with CT, but the percentage of speed improvement with trials was similar, suggesting similar learning curves, with minimal transfer effect appreciated.
Atmospheric modulation transfer function for desert and mountain locations: the atmospheric effects on r 0

In conjunction with recent atmospheric modulation transfer function (MTF) measurements for desert and mountain locations, the distribution of optical turbulence within the planetary boundary layer was measured by using tower, aircraft, and acoustic sounder techniques. Diurnal variations in the atmospheric turbulence within 1–3 km above the surface dominate the MTF observations. During convective, daylight hours, desert and mountain boundary layers are found to be similar. The magnitudes of optical turbulence (Cn2) are comparable, and similar thermal plume structures are observed. In addition, optical turbulence is found to have a simple (Δθ)4/3 dependence on the air–surface temperature difference. At night, the cool ground surface produces turbulent, stratified layers above a desert that are not observed for a mountain. The effects of tower height above the ground are investigated theoretically and experimentally. MTF measurements made 2 and 8 m above the desert during the day are in good agreement with theoretical models. We observe interrelationships between the turbulent boundary layer and the atmospheric MTF that can be applied to the selection of both astronomical and solar telescope site locations.
Conformation of sequential polypeptides of (Lysi-Leuj), (Lysi-Serj), and (Lys-Gly) in sodium dodecyl sulfate solution.

A series of sequential polypeptides (LysiRj)n (R is Leu, Ser, or Gly) and random copolypeptides, (Lysx, Leuy)n, were synthesized. Their conformation in NaDodSO4 solution was determined by CD. Only (Lys-Leu)n, (Lys-Ser)n, and (Lys3-Ser)n adopt a stable β-form in the surfactant solution; (Lys-Ser2)n, (Lys-Ser3)n, (Lys2-Ser2)n, and (Lys2-Ser)n have an unstable β-form, which reverts to an unordered form in high NaDodSO4 concentrations, even though both Ser and DodSO-bound Lys+ are β-formers. In contrast, (Lys-Gly)n remains unordered in NaDodSO4 solution. On the other hand, Lys-rich (Lys2-Leu)n forms an unstable helix and (Lys2-Leu2)n a stable helix in NaDodSO4 solution. In 25 mM NaDodSO4 (Lysx, Leuy)n also forms a helix up to x = 75 and reverts to the β-form at x = 90. This compares with the helical conformation of (Lysx, Alay)n up to x = 65 and its β-form at x = 90, suggesting that Leu is an even stronger helix-former than Ala. Our results may provide a plausible explanation for the increase in helicity and disruption of the β-form for many proteins in NaDodSO4 solution, that is, the polypeptide chain of a protein usually favors a helical conformation over a β-form in the presence of excess surfactant.
Late Preterm Infants, Early Term Infants, and Timing of Elective Deliveries

Delivery of infants who are physiologically mature and capable of successful transition to the extrauterine environment is an important priority for obstetric practitioner. A corollary of this goal is to avoid iatrogenic complications of prematurity and maternal complications from delivery. The purpose of this review is to describe the consequences of birth before physiologic maturity in late preterm and term infants, to identify factors contributing to the decline in gestational age of deliveries in the United States, and to describe strategies to reduce premature delivery of late preterm and early term infants.
Mineral status of cattle in the San Carlos region of Costa Rica.

Abstract Two experiments on 12 beef and 9 dairy cattle farms were to determine the mineral status of grazing cattle in the San Carlos region of Costa Rica by evaluating concentrations of minerals in liver, plasma, bone ash, forages, and oxalate contents of forages. Copper ( In dairy cattle, 10 samples of blood and 1 to 2 of forage were collected on each of 5 farms with and 4 farms without the forage Setaria sphacelata . Calcium (.29%) and phosphorus (.18%) concentrations in forage were low in relation to requirements of lactating dairy cows. Phosphorus in plasma was deficient ( Setaria pastures (2.30%) than in other pastures (1.24%). Low calcium and phosphorus in forage and high oxalate in Setaria pastures may be responsible for the high incidence of a milk fever-like condition in dairy cattle.
Simulation of electrochemical nucleation in the presence of additives under galvanostatic and pulsed plating conditions

Abstract Galvanostatic nucleation of copper onto pretreated ruthenium is investigated using experimental methods and numerical simulations in the presence of two different suppressor molecules; polyethylene glycol (PEG) and ethylene glycol–propylene glycol–ethylene glycol block copolymer (EPE). The model parameters have been largely determined from electrochemical characterization. Results suggest that a fast adsorption rate of the suppressor results in higher nucleus densities. Simulation results provide insight why EPE is more effective than PEG at increasing nucleus density. In addition, the simulations are used to predict the impact of pulse plating paramaters, showing that both the properties of the additive and the waveform need to be considered to optimize nucleus density enhancement.
Statistical Discrimination and the Implication of Employer-Employee Racial Matches

In this paper, I test the empirical validity of a statistical discrimination model that incorporates employer’s race. I argue that if an employer statistically discriminates less against an employee that shares the same race (matched) than an employee who does not share the same race (mismatched), then the correlation between the employee’s wage and his skill level (AFQT) is stronger for a matched employee than for a mismatched employee. Using data from the NLSY97, which includes information about the racial background of employees and their supervisors, I find evidence that is consistent with a statistical discrimination model for young male employees.
Behaviorally specific versus non-specific suppression of accumbens shell-mediated feeding by ipsilateral versus bilateral inhibition of the lateral hypothalamus.

Abstract The nucleus accumbens shell (AcbSh) and lateral hypothalamus (LH) are linked in the control of food intake. Pharmacological inhibition of the LH may block AcbSh-elicited feeding, but the behavioral phenotype associated with this feeding suppression is unknown. To examine this phenotype, adult male Sprague-Dawley rats were implanted with three cannulas – one unilaterally in the AcbSh and two bilaterally in the LH – to allow for central drug injections. The AcbSh received injections of the AMPA receptor antagonist DNQX or the GABA A receptor agonist muscimol, while the LH received injections of the NMDA receptor antagonist D-AP5 or muscimol. Eating, drinking, grooming, locomotion, quiescence, and sleeping behaviors were measured every minute for 60 min post-injection. From these observational data, feeding bout durations, feeding frequency, and latency to feed were determined. AcbSh muscimol or DNQX increased food intake by increasing feeding bout durations and frequency and decreasing latency to feed. D-AP5 or muscimol, injected into the LH bilaterally or ipsilateral to the AcbSh injection, reversed these AcbSh-mediated effects. Though bilateral LH D-AP5 or muscimol injections blocked feeding responses, they also hastened onset of sleep. In contrast, ipsilateral LH D-AP5 or muscimol injections suppressed AcbSh-mediated feeding behaviors without substantially altering sleeping or other behaviors. These results suggest bilateral LH inhibition via NMDA receptor blockade or GABA A receptor activation produces behavioral effects that might indirectly suppress feeding, but ipsilateral LH inhibition through these receptors suppresses AcbSh AMPA and GABA A receptor-mediated feeding specifically. This evidence strengthens the concept of a feeding-specific association between these regions.
A REEVALUATION OF THE BIOCHRONOLOGY OF THE BRISBANE AND JUDSON LOCAL FAUNAS (LATE PALEOCENE) OF NORTH DAKOTA

Abstract The best-known and most diverse mammalian faunas from the Fort Union Group of North Dakota are the Brisbane and Judson local faunas, both historically considered as mid Tiffanian (Ti3, mid-late Paleocene). Our review of the stratigraphic context of the localities provides no lithologic reasons for continued use of the terms Slope and Bullion Creek Formations, and we propose abandoning these terms in favor of the Tongue River Formation. Revised faunal lists were completed for this paper using taxonomic revisions published after the original 1978 study. The chronostratigraphic ranges of Brisbane and Judson taxa were then used to determine the biochronology of the faunas. The Brisbane local fauna is corroborated as being Ti3 based upon a combination of first appearance (Leptacodon tener, Thryptacodon australis, Dorraletes diminutivus) and last appearance (Pararyctes pattersoni, Ectocion collinus) data, together with taxa reported only from Ti3 faunas (Bisonalveus holtzmani, Plesiadapis rex, Aletodon...
Josamycin and Rosamicin: In Vitro Comparisons with Erythromycin and Clindamycin

The macrolide antibiotics josamycin and rosamicin were compared in vitro with erythromycin for activity against Staphylococcus aureus, S. epidermidis, and enterococci and with clindamycin for activity against a variety of anaerobic organisms. Rosamicin and erythromycin were similar in activity and superior to josamycin against aerobic cocci. Most isolates of S. aureus (96%), S. epidermidis (79%), and the enterococci (87%) were inhibited by 1.56 mug of either of the new macrolide compounds per ml. Clindamycin was the most active compound against the anaerobic organisms.
Glucose oxidation in the ventromedial hypothalamus is not affected by insulin or ouabain but depressed by alloxan treatment

Insulin is apparently not required for VMH glucose oxidation in vitro. Ouabain, an inhibitor of the Na-K pump ATPase, does not prevent VMH glucose oxidation in vitro. These data suggest (a) the VMH does not exhibit a cotransport phenomenon of glucose with the Na-K pump mechanism, and (b) glucose oxidation in the VMH is not insulin dependent. Alloxan-diabetes was induced to increase tissue insulin sensitivity. A comparison of glucose oxidation rates in alloxan-diabetic VMH tissue and normal VMH tissue, supplemented only with saline, indicated a highly significant (p < 0.001) depression of glucose oxidation in the alloxan-treated tissue. Cell membranes in the VMH are perhaps altered by alloxan.
Effect of a cytotoxic analog of LH-RH (T-98) on the growth of estrogen-dependent MXT mouse mammary cancers : correlations between growth characteristics and EGF receptor content of tumors

Female BDF mice bearing estrogen-dependent MXT mouse mammary cancers were treated for 4 weeks with a cytotoxic analog of luteinizing hormone-releasing hormone (LH-RH), T-98 (agonist [D-Lys6]LH-RH linked to glutaryl-2(hydroxymethyl)anthraquinone). The effects of T-98 were compared to those of equimolar amounts of the cytotoxic moiety 2-(hydroxymethyl)anthraquinone hemiglutarate (G-HMAQ) and carrier LH-RH agonist [D-Lys6]LH-RH. Both T-98 and [D-Lys6]LH-RH significantly inhibited the growth of MXT cancers, but G-HMAQ had only a minor non-significant effect. Cytotoxic analog T-98 and the carrier [D-Lys6]LH-RH had similar inhibitory hormonal activities on the pituitary-gonadal axis, but T-98 caused a larger reduction in tumor volume and decreased proliferation characteristics such as mitotic activity and AgNOR numbers in tumor cells to a greater extent than the carrier. Tumor inhibition by T-98, [D-Lys6]LH-RH, and ovariectomy was connected with a significant decrease in binding capacity of EGF receptors in tumor cell membranes. The concentration of EGF receptors remained high in tumors that continued to enlarge in spite of treatment and in all control untreated tumors, even those of small size. Thus, the changes in EGF receptors are likely to be the result of the therapy. Treatment with T-98 caused a greater reduction in the binding capacity of EGF receptors in tumors than [D-Lys6]LH-RH. This could explain the higher inhibitory effect of the cytotoxic analog on tumor growth. Since radiolabeled T-98 was shown to accumulate in MXT cancers 3 hours after a subcutaneous injection, this indicates that specific targeting might play a role in the antitumor effect exerted by this cytotoxic analog.
Complications of third-trimester amniocentesis using continuous ultrasound guidance

Abstract OBJECTIVE: The objective of the study was to estimate the risks of third-trimester amniocentesis with continuous ultrasound guidance. METHODS: Cohort study. We reviewed the medical records of women who had an amniocentesis with continuous ultrasound guidance after 30 weeks’ gestation at a single institution from January 1991 through December 1994. For procedures performed from January 1991 to February 1994, we obtained information from a chart review. From March 1994 to December 1994, we collected data prospectively. The primary outcome was whether or not there were any complications within 48 hours of the procedure. We also sought to determine any risk factors associated with complications. RESULTS: Complete records and data were available for 562 amniocenteses during the study period. The mean gestational age at the time of amniocentesis was 34.9 weeks. Of the 562 procedures, five (0.8%) were unsuccessful and 50 (9%) required more than one needle stick. The complication rate was 0.7% (95% confidence level (CI) = 0.02%, 1.9%). These included spontaneous labor in a preterm gestation (1), premature rupture of the membranes (1), placental abruption (1), and fetal-maternal hemorrhage (1). No patient required an emergency cesarean delivery and none suffered a perinatal death (95% CI 0, 0.8%). Complications were not associated with the number of needle sticks, the presence of bloody amniotic fluid, or the level of operator experience. CONCLUSIONS: Third-trimester amniocentesis performed with continuous ultrasound guidance has a high success rate and low risk for complications.
The Effects of Target Borders on Dynamic Visual Acuity: Practical and Theoretical Implications

The effects of target borders on the ability of observers to resolve moving targets (Landolt Cs) under a range of conditions were examined. Contrary to reported findings with stationary targets, it was predicted that the presence of borders would improve acuity for slow-moving targets because (i) overall stimulus energy is kept relatively constant as target detail varies, and (ii) a low-spatial-frequency component is held constant as target detail varies. In an experiment in which a two-sided border (above and below the target) was used, the predicted beneficial effect of the border at slow speeds was obtained. The results are discussed in terms of practical implications for the assessment of dynamic visual acuity as well as the potential neural mechanisms underlying performance.
Reduced metallic clusters and homogeneous cluster compounds “supported” on aluminum oxide as studied by inelastic electron tunneling spectroscopy

Abstract Inelastic electron tunneling spectroscopy has been applied to characterize both supported reduced metallic particles and supported homogeneous cluster catalysts. In particular, the interaction of C2H5OH with clusters of Ag supported on Al2O3, and of Zr(BH4)4, [RhCl(CO)2]2 and Ru3(CO)12 on Al2O3 have been examined, including the interaction of C2H4, C3H6 and C2H2 with the supported polymerization catalyst, Zr(BH4)4.