cssi/SciSciGPT-SciSciNet huggingface dataset:
Greenhouse warming and the 21st century hydroclimate of southwestern North America.

Climate models robustly predict that the climate of southwestern North America, defined as the area from the western Great Plains to the Pacific Ocean and from the Oregon border to southern Mexico, will dry throughout the current century as a consequence of rising greenhouse gases. This regional drying is part of a general drying of the subtropics and poleward expansion of the subtropical dry zones. Through an analysis of 15 coupled climate models it is shown here that the drying is driven by a reduction of winter season precipitation associated with increased moisture divergence by the mean flow and reduced moisture convergence by transient eddies. Due to the presence of large amplitude decadal variations of presumed natural origin, observations to date cannot confirm that this transition to a drier climate is already underway, but it is anticipated that the anthropogenic drying will reach the amplitude of natural decadal variability by midcentury. In addition to this drop in total precipitation, warming is already causing a decline in mountain snow mass and an advance in the timing of spring snow melt disrupting the natural water storage systems that are part of the region’s water supply system. Uncertainties in how radiative forcing will impact the tropical Pacific climate system create uncertainties in the amplitude of drying in southwest North America with a La Nina-like response creating a worst case scenario of greater drying.
Analysis of transcriptional initiation of yeast mitochondrial DNA in a homologous in vitro transcription system

Abstract We have developed an in vitro transcription system for yeast mitochondrial rRNA genes. Using highly purified yeast mitochondrial RNA polymerase and bacterial plasmids carrying DNA segments containing the mitochondrial rRNA sites of transcriptional initiation, we have been able to demonstrate correct initiation of transcription in vitro. By directly sequencing the transcription products, we show that transcription in vitro of both the 14S and 21 S rRNAs is initiated at precisely the same site as it is in vivo. Transcription of the rRNA genes is highly sensitive to ionic strength and RNA polymerase concentration. Additional factors or modified conditions may be necessary to permit accurate transcription of mitochondrial protein genes.
Exhaust Aerosol of a Plasma Enhanced CVD System: II. Electrical Charging and Transport

The microelectronics industry has been concerned about the loss of product yield in its semiconductor wafer processing steps from killer defects caused by the presence and deposition of contaminant particles. Reactant gases used in plasma enhanced chemical vapor deposition (PECVD) can form nanometer sized particles from homogeneous nucleation. Once the particles grow to a few nanometers, they become negatively charged due to the collected ion and electron currents on the particle surface. A gradient of the electron and ion concentration between the sheath and bulk plasma causes an electric field to develop directed to the walls. Contaminant particles can eventually become trapped in electrostatic potential wells due to the higher charge density of positive ions near the powered electrode. The traps fill in the plasma sheath region until some particles are "leaked out" by gas drag forces. Therefore particles formed solely in the plasma volume are theorized to possess a distinct charge level from condensati...
A nutritional analysis of foraging in the Malabar giant squirrel (Ratufa indica)

The effect of nutrients and their availability on the diet of the herbivorous Malabar giant squirrel Ratufu indicu (Sciuridae) was investigated at Magod and Bhimashankar in western India. The daily consumption of food items (percent wet diet) and the intake rates of these items and the contained nutrients (wet g s-I) were determined by continuous observation of focal animals. Water content was a significant positive predictor of relative food item consumption while mineral contents in general had the opposite effect. The intake rates of water and more digestible nutrients such as nonstructural carbohydrates, as well as the intake rate of minerals such as zinc (at Magod), were significant positive predictors of the relative contribution of an item to the daily diet, thus indicating considerations of feeding costs versus benefits. Tannins, some alkaloids, and other secondary metabolites may negatively influence food choice. Protein content, relative to digestibility reducers, influenced food item consumption only at Bhimashankar. There was seasonal variation in daily biomass consumption. At Bhimashankar, daily biomass consumption increased with the proportion of fruit in the diet while this did not occur at Magod. This is perhaps a result of the higher water content and the lower content of some soluble nutrients within fruit at Bhimashankar relative to Magod. There was also intra-month variation between individual squirrels in daily biomass of food consumed. Squirrels consumed ephemera1 food items opportunistically and non-ephemeral items such as mature leaves and bark on a regular daily basis. Squirrels probably obtained minerals and nitrogen from both fruit (especially seeds) and non-fruit sources (mature leaves and bark in the case of minerals, young and mature leaves in the case of nitrogen). However, they obtained lipid and non-structural carbohydrates mostly from fruit. Squirrels were selective in their utilization of tree species on a monthly basis, but this selectivity was not evident over a longer time period because individuals were constrained to use different phenological stages of tree species present within their territories. Large body size in this squirrel permits dietary flexibility and enables an overall generalist feeding strategy.
450 Hz relative frequency stability in an AlGaAs diode laser

A commercial AlGaAs diode laser is frequency-locked to a Fabry-Perot interferometer. The temperature stabilisation loop of the diode laser system maintains the relative stability within 11 kHz. When the frequency control loop is closed, the relative frequency stability is improved to 450 Hz.
Ocular coloboma and dorsoventral neuroretinal patterning defects in Lrp6 mutant eyes

Coloboma, an ocular birth defect seen in humans and other species, is caused by incomplete closure of the optic fissure. Here, we demonstrate that genetic deletion of Lrp6, a bottleneck coreceptor in the canonical Wnt signaling pathway, results in ocular coloboma and neuroretinal patterning defects in mice. The expression of ventral neuroretinal patterning gene Vax2 was conserved but with dorsally shifted expression domains; however, the dorsal neuroretinal patterning gene Tbx5 was lost in the Lrp6-mutant eyes at embryonic day 10.5. Both Bmp4 and phosphorylated Smad 1/5/8 were also significantly attenuated in the dorsal neuroretina. In addition, the retinoic acid synthesizing enzymes Raldh1 and Raldh3 were significantly changed in the mutant eyes. Our findings suggest that defective retinal patterning causes coloboma in the Lrp6-deficient mice, and that canonical Wnt signaling plays a primary role in dorsal neuroretinal patterning and related morphogenetic movements by regulation of both Bmp and retinoic acid signaling pathways.
Impact of lubricating oil on particulates formed during combustion of diesel fuel: a shock tube study

Abstract The advent of more stringent standards to reduce particulate emissions has increased the need to control the contribution that consumption of lubricating oil in engines makes toward particle emissions. Although many studies have been done in this area, the main mechanism by which lubricating oil contributes to particle formation is not well understood. In this study, the impact of lubricating oil on particle emissions from diesel fuel combustion was investigated. Combustion of D-2 diesel fuel with two concentrations of Pennzoil 10W40 motor oil (0.5 and 2 wt%) was studied over a temperature range of 1200–2300 °C at pressures of 5, 14 and 24 atm. All experiments were conducted in a modified single pulse reflected shock tube. The fuel and lubricating oil mixtures were injected using a high pressure fuel injector. The addition of lubricating oil led to higher particulate yields at higher combustion pressures. The increase was more evident with higher lubricating oil concentrations. However, at lower pressures, neither concentrations of lubricating oil had any impact on particulate yield. The results agree with previous studies where an increase in particulate yield was observed with an increase in lubricating oil consumption and pressure. The results observed confirm the hypothesis that lubricating oil present in the combustion chamber during the combustion process could contribute to particle emissions.
Studies on the in vivo methylation of DNA in Escherichia coli 15T.

Abstract The in vivo methylation of the DNA of Escherichia coli 15T− has been studied. The DNA of this organism contains small amounts of both methylated adenine and cytosine. It was found that the nascent polynucleotide strand is methylated as DNA is replicated and that the degree of methylation depends upon the medium methionine concentration. A methylated region of the chromosome is stable during subsequent growth and can be shown to be replicated sequentially. When this organism is starved of methionine, DNA can be synthesized without concomitant methylation. However, upon restoration of methionine, most of this DNA is methylated before DNA synthesis is resumed. There does not appear to be any appreciable pool of methylation precursors available for the methylation of DNA within the cell during methionine starvation.
The Market as a Matter of Money: Denaturalizing Economic Currency in American Constitutional History

Histories of the early American political economy present that world in fractured form, dividing political and constitutional dimensions from economic aspects. The fragmented approach reflects an old, oft-denigrated, but still powerful imagery, one that naturalizes economic activity as a set of myriad spontaneous and individuated exchanges, conducted with a conventional medium, money, and predictably composing a market sphere. The motif and its underlying assumptions in turn dissuade exploration of money and markets as territories of public decision, insulating by neglect the structural power of determinations made there. This essay traces the naturalization motif through a historiography of macroeconomic models of money. It then considers how money, recognized as a dynamics of value, would look if the law structuring it were approached as a complex set of relations that expressed, reiterated, and revised the distribution of authority in society. The early American political economy appears in a different light: money becomes a matter of value and governance at once, and therefore a crucial area of constitutional debate. Through that medium, the political economy of early America is transformed not once but repeatedly, from a mercantilist to a domestic paper to a liberal capitalist form.
Some pitfalls in curve-fitting and how to avoid them: A case in point

When curve-fitting is used to support a complex nonlinear model containing several exponential terms, some of which have closely-spaced time constants, a particular burden of proof must be assumed. Most important, the uniqueness of the solution must be explored and discussed. Statistical tests for the degree of error and independence of the parameters should be provided, as well as information relating to the steps actually used in the fitting procedures. As an example of the need for the procedures we recommend in this communication, we have chosen an important case in point that has been published recently, and which deals with the kinetics of electron transfer from fully-reduced cytochrome oxidase to O2, analyzed by the method of SVD-based least squares. The problems we deal with in this case are applicable to a wide variety of other cases that involve curve-fitting to mathematical models.
Motor Neuron Differentiation from Pluripotent Stem Cells and Other Intermediate Proliferative Precursors that can be Discriminated by Lineage Specific Reporters

We have used a four stage protocol to generate spinal motor neurons (MNs) from human embryonic stem cells (ESCs) and human induced pluripotent stem cells (iPSCs). These stages include the pluripotent stem cell (PSC) stage, neural stem cell (NSC) stage, OLIG2 expressing motor neuron precursor (MNP) stage, and HB9 expressing mature-MN stage. To optimize the differentiation protocol reporter lines marking the NSC and MNP stages were used. The NSC stage is a pro-proliferative precursor stage at which cells can be directed to differentiate to other neural types like cortical neurons also, in addition to MNs; thus, NSCs can be expanded and stored for future differentiation to different neural types thereby, shortening the differentiation interval as compared to the complete process of differentiation from ESCs or iPSCs. Additionally, we find that OLIG2 positive cells at the MNP stage can be cryopreserved and then recovered to continue the process of MN differentiation, thereby providing a highly stable and reproducible technique for bulk differentiation. MNPs were differentiated to MNs expressing the marker HB9 demonstrating that mature-MNs can be generated with this protocol.
Importance of pharmacokinetic studies in the management of acquired factor X deficiency

Up to 14% of individuals with systemic AL amyloidosis develop acquired factor X deficiency, which occurs due to adsorption of factor X onto amyloid fibrils. Although baseline factor X levels are not predictive of bleeding risk in these patients, serious hemorrhagic complications can occur, particularly during invasive procedures. Optimal management strategies to attenuate bleeding risk in these patients are unknown. We describe our experience in the management of acquired factor X deficiency, secondary to systemic AL amyloidosis, in a case series of three patients who received prothrombin complex concentrates (PCCs) for treatment and prevention of bleeding events. We performed a retrospective review extracting information on baseline demographics, laboratory data, pharmacokinetic (PK) studies, and clinically documented bleeding events. Our case series demonstrates that individuals with acquired factor X deficiency secondary to amyloidosis have variable laboratory and clinical responses to PCCs. This is likely due to distinct amyloid loads and fibril sequences, leading to different binding avidities for factor X. Our data emphasize the importance of performing PK testing prior to any invasive procedures to determine the dose and frequency interval to achieve adequate factor X levels for hemostasis, given the variable response between individuals.
Further investigation of polyaminoamide-epichlorohydrin/stearic anhydride compatibilizer system for wood-polyethylene composites

The combination of a polyaminoamide-epichlorohydrin (PAE) resin (a paper wet strength agent) and stearic anhydride was recently reported as an effective compatibilizer system for wood-polyethylene composites. Further investigation of this new compatibilizer system revealed that the pH value of a PAE solution, dosages of PAE and stearic anhydride, and the weight ratio of PAE to stearic anhydride had significant impacts on the compatibilization effects of the compatibilizer system. Adjusting the pH value of the PAE solution from 5.0 to 10.4 increased the strength of the resulting wood-polyethylene composites. The highest strength of the resulting wood-polyethylene composites was obtained at 3 wt % PAE and 3 wt % stearic anhydride. At 4 wt % or 6 wt % of a compatibilizer, this PAE-stearic anhydride system was superior to maleic anhydride-grafted polyethylene (MAPE), one of the most effective compatibilizers, in terms of enhancing the strength of the resulting wood-polyethylene composites. Fourier transform infrared spectroscopy (FTIR) analysis revealed that PAE and stearic anhydride formed covalent bonding with wood flour. The compatibilization mechanisms of this PAE-stearic anhydride compatibilizer system were investigated in detail. Water-resistance tests indicated that the PAE-stearic anhydride compatibilizer system increased the water-resistance of the resulting composites. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 712–718, 2006
Two-Ion Interference: Bragg Scattering and Superradiance.

Bragg scattering and superradiance, always considered independently, are examined jointly for the case of two trapped ions. The two phenomena are seen to be different representations of the same basic two-ion interference resulting from a common coherent optical preparation. Solutions of a master equation for two four-level atoms show that fringes (spatial interference) and a variation of the spontaneous emission lifetime with ion-ion distance (temporal interference) can occur either simultaneously or separately. Unlike a classical calculation, not all scatterings result in interference, a quantum effect not considered in interpreting recent experiments.
College students use cell phones while driving more frequently than found in government study

Objective Cell phone use while driving is hazardous; it quadruples the risk of a collision and multiplies the risk of a fatality nine-fold. The National Highway Traffic Safety Administration estimates that 8% of young drivers and 5% of all drivers use cell phones while driving. Participants and Methods The authors trained graduate student volunteers to observe the daytime cell phone use of 3,650 drivers leaving the student exits of college parking structures at a large university. Results The student observers recorded a cell phone usage rate of 11.1%, which was significantly higher than that seen in the National Occupant Protection Use Survey (p < .00001). Female drivers were 1.51 times more likely to be using a cell phone while driving than were men (12.9% vs 8.6%, p < .001), and drivers with passengers were 0.15 times more likely to drive while telephoning than were solo drivers (1.8% vs 12.1%, p < .001). Conclusions The authors offer suggestions for possible interventions to reduce this hazardous beha...
Locating Praxis for Equity in Mathematics: Lessons From and for Professional Development

In this article, the authors report on a study that contributes to a growing body of literature that considers professional development (PD) focused on mathematics and equity. The authors examined how lived experiences provide a foundation for the ways teachers take up equity in their mathematics teaching practice. The constructs of praxis and figured worlds are used to frame the study. In particular, teachers’ identities in the figured worlds of standards-based mathematics, multicultural education, and equitable mathematics pedagogy were explored with a focus on how they contributed to where the teachers located praxis for equity in mathematics. The teachers’ lived experiences and their participation in the PD were analyzed with an eye toward teachers’ evolving identities and how they contribute to where teachers located praxis.
Optimized homology searches of the gene and protein sequence data banks

Abstract A strategy is presented for searching the gene and protein sequence data banks which combines the use of two previously described algorithms. The implementation of this strategy is thoroughly evaluated with respect to sensitivity, specificity and speed. The establishment of standard benchmarks for comparing programs that search the sequence data banks for homology is proposed.
Synthetic chemistry: making a natural fuel cell.

The synthetic assembly of the active centre of hydrogen-producing enzymes adds to our understanding of their structure and function — and could produce new and useful materials that mimic these enzymes. In conventional hydrogen fuel cells the rapid interconversion of protons and electrons to hydrogen requires catalysis by expensive metals, usually platinum. In the living world enzymes catalyse this same reaction at extraordinary rates using abundant metals. Tard et al. now report the chemical synthesis of the iron–sulphur structure at the heart of the hydrogenase protein. The resulting iron–sulphur framework functions as an electrocatalyst for proton reduction, a potentially important step towards new materials to replace platinum in the anodes of fuel cells.
General construction of force-free current filaments

A complete construction of cables with vanishing Lorentz self-force is given (solution of the cylindrically symmetric force-free problem for nonconstant {alpha}). A key component of the result is that boundary conditions are intrinsic and cannot be imposed, which implies that many previous solutions of the problem are in fact spurious. Two force-free current ropes are constructed as an illustration. These results have applications in magnetic fusion; space physics, solar physics, and astrophysics; force-reduced superconducting magnet windings; and superconducting cables for power transmission.
Management of Mycobacterium abscessus post abdominoplasty.

Atypical mycobacterium is the source of a recent outbreak of cosmetic surgery infections [1]. Such an infection is difficult to eradicate and presents unique challenges in its management after esthetic surgery. Delays in appropriate treatment are frequent because of difficulty in diagnosis and unfamiliarity with this type of infection. We present cases of our management of Mycobacterial abscessus abdominoplasty infections following cosmetic surgery in the Dominican Republic. Rapid initial recognition of this problem and the frequent need for surgical treatment of atypical mycobacterium abdominoplasty infection may aid in the treatment of this rare but increasingly encountered infection. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .
Estimation of contact force on composite plates using impact-induced strain and neural network

A method of determining the contact force on laminated composite plates subjected to low velocity impact is developed using the finite element method and a neural network. The back propagation neural network is used to estimate the contact force on the composite plates using the strain signals. The neural network is trained using the contact force and strain histories obtained from finite element simulation results. The finite element model is based on a higher order shear deformation theory and accounts for von-Karman nonlinear strain-displacement relations. The nonlinear time dependent equations are solved using a direct iteration scheme in conjunction with the Newmark time integration scheme. The training process consists of training the network with strain signals at three different locations. The effectiveness of different neural network configurations for estimating contact force is investigated. The neural network approach to the estimation of contact force proved to be a promising alternative to more traditional techniques, particularly for an on-line health monitoring system.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TRACE FIELDS OF TWIST KNOTS

In this paper we compute the trace field for the family of hyperbolic twist knots. We describe this field as a simple extension ℚ(z0) where z0 is a specified root of a particular irreducible polynemial Φn(z)∈ℤ[z]. As a consequence, we find that the degree of the trace field is precisely two less than the-minimal crossing number of a twist knot.
STEPS TOWARD INCREASING Q IN MIRROR SYSTEMS

ABSTRACT Experiments such as the 2XIIB experiment at Livermore have established the ability of mirror systems to confine high temperature, high density plasmas at central beta values exceeding unity. Given these results the next tasks for the mirror approach are to explore means for increasing the energy gain factor Q and to scale up the plasma volume, both of these requirements deriving from economic constraints. This report will discuss means for increasing Q, including recent improvements in the tandem mirror concept and design studies of the field-reversed mirror in the context of upcoming and proposed scaled-up mirror experiments.
Target enhancement and noise cancellation in the identification of a rudimentary sound source in noise

Perturbation analysis was used to determine the relative contribution of target enhancement and noise cancellation in the identification of rudimentary sound source in noise. In a two-interval, forced-choice procedure, listeners identified the impact sound produced by the larger of two stretched membranes as target. The noise on each presentation was the impact sound of a variable-sized plate. For four of five listeners, the relative weights on the noise were positive indicating enhancement, and for the remaining listeners, they were negative indicating cancellation. The results underscore the difficulty with evaluating models of masking solely in terms of measures of performance accuracy.
Ideal-Fluid Thermocline with Weakly Convective Adjustment in a Subpolar Basin

Abstract The ideal-fluid thermocline with continuous stratification is extended to include a weakly convective adjustment process taking place in a subpolar basin. The convective adjustment creates a well-mixed layer on top of a moving unventilated thermocline were potential vorticity is specified as a boundary condition. Convective adjustment makes the moving water stratum shallower and the current more surface-intensified.
Hierarchical coarse-graining strategy for protein-membrane systems to access mesoscopic scales

An overall multiscale simulation strategy for large scale coarse-grain simulations of membrane protein systems is presented. The protein is modeled as a heterogeneous elastic network, while the lipids are modeled using the hybrid analytic-systematic (HAS) methodology, where in both cases atomistic level information obtained from molecular dynamics simulation is used to parameterize the model. A feature of this approach is that from the outset liposome length scales are employed in the simulation (i.e., on the order of 1/2 a million lipids plus protein). A route to develop highly coarse-grained models from molecular-scale information is proposed and results for N-BAR domain protein remodeling of a liposome are presented.
Failure of reticulose to reduce radiation lethality in mice and rats.

SummaryReticulose given by subcutaneous injection to mice, with and without streptomycin treatment, failed to alter mortality, leucocyte count, or incidence of blood stream infection after 625 r whole-body X-irradiation. Given to rats it failed to alter mortality after 570 r whole-body X-irradiation.
How much e-waste is there in US basements and attics? Results from a national survey.

The fate of used electronic products (e-waste) is of increasing concern because of their toxicity and the growing volume of e-waste. Addressing these concerns requires developing the recycling infrastructure, but good estimates of the volume of e-waste stored by US households are still unavailable. In this context, we make two contributions based on a national random survey of 2136 US households. First, we explain how much e-waste is stored by US households using count models. Significant explanatory variables include age, marital and employment status, ethnicity, household size, previous e-waste recycling behavior, and to some extent education, home ownership, and understanding the consequences of recycling, but neither income nor knowledge of e-waste recycling laws. Second, we estimate that on average, each US household has 4.1 small (≤10 pounds) and 2.4 large e-waste items in storage. Although these numbers are likely lower bounds, they are higher than recent US Environmental Protection Agency (EPA) estimates (based on narrower product categories). This suggests that the backlog of e-waste in the US is likely larger than generally believed; it calls for developing the recycling infrastructure but also for targeted recycling campaigns.
Environmental performance standards and the adoption of technology

Abstract This paper examines the argument that environmental performance standards offer a relative disincentive for the adoption of cleaner technologies, and it shows that this relative disincentive exists when regulators cannot credibly commit to a stringent environmental standard. The relative disincentive is alleviated if the firms are sufficiently heterogeneous in the adoption costs, if the regulator engages the firm repeatedly, or if the regulator can combine an environmental performance standard with another instrument, such as a subsidy to the adoption of a cleaner technology or fines for non-compliance.
Science Signaling Podcast: 6 March 2012

This Podcast features a conversation with authors of a Research Article published in the 6 March 2012 issue of Science Signaling . Joan Brugge and John Albeck discuss their work on a mechanism of crosstalk between growth factor signaling pathways that control proliferation in breast epithelial cells. Insulin-like growth factor 1 (IGF-1) and epidermal growth factor (EGF) both promoted proliferation of breast epithelial cells, but only EGF stimulated proliferation on its own. IGF-1 did not stimulate proliferation on its own, but instead enhanced the proliferative response to EGF. The signaling cascades stimulated by EGF and IGF-1, which are commonly used as indicators of oncogenic signaling, differentially regulated the activity of the cell cycle inhibitor p57. Thus, the status of p57 may indicate which pathway to inhibit in breast cancer.
Scheduling to minimize average completion time: off-line and on-line algorithms

Time-indexed linear programming formulations have recently received a great deal of attention for their practical effectiveness in solving a number of single-machine scheduling problems. We show that these formulations are also an important tool in the design of approximation algorithms with good worst-case performance guarantees. We give simple new rounding techniques to convert an optimal fractional solution into a feasible schedule for which we can prove a constant-factor performance guarantee, thereby giving the first theoretical evidence of the strength of these relaxations. Specifically, we consider the problem of minimizing the total weighted job completion time on a single machine subject to precedence constraints, and give a polynomial-time (4 + {epsilon})-approximation algorithm, for any {epsilon} > 0; the best previously known guarantee for this problem was superlogarithmic. With somewhat larger constants, we also show how to extend this result to the case with release date constraints, and still more generally, to the case with m identical parallel machines. We give two other techniques for problems in which there are release dates, but no precedence constraints: the first is based on other new LP rounding algorithms, whereas the second is a general framework for designing on-line algorithms to minimize the total weightedmore » completion time.« less
Interpretation of distortion product otoacoustic emission measurements. II. Estimating tuning characteristics using three stimulus tones

The simple model introduced in Part I [J. Acoust. Soc. Am. 102, 413–429 (1997)] is used to simulate the response of the cochlea to three stimulus tones. The focus is on “emission suppression tuning curves” constructed using a third tone to suppress the cubic distortion tone emission (CDT, 2 f1−f2) generated by two primary tones at frequencies f1 and f2 (intensities L1 and L2). A criterion decrease (here, 5 dB) of the CDT emission amplitude defines the 2 f1−f2 emission suppression tuning curve. Applying traditional tuning curve measures to emission suppression tuning curves appears ineffective in determining the underlying cochlear amplifier characteristics. However, it is shown that there are three characteristics of emission suppression tuning curves which are particularly useful: (1) the “f2 threshold” which is the level of the third tone, L3, required for the criterion CDT amplitude decrease, under the condition that the third tone frequency, f3, is approximately equal to f2; (2) the “shoulder threshol...
Possible effects of fixed membrane surface charges in experiments on excitation-contraction coupling in frog muscle

Abstract 1. 1. A number of experiments on excitation-contraction coupling have not yet been interpreted reasonably. For example, the contractures of tonic muscle fibers in non-ionic or NaCl solutions, and the relaxation of these muscles by divalent cations; the increase in twitch muscle respiration in non-ionic solutions; the shift in mechanical threshold with changes in extra-cellular divalent cation concentrations; or the change in mechanical threshold in the presence of anions like nitrate or thiocyanate or of certain drugs. 2. 2. It is proposed that these effects can be accounted for by changes in the voltage gradient within the membrane. These changes are produced by altering the negativity of the surface potential on the outer face of the sarcolemma by cations that screen or bind to the fixed charges, or by the absorption of charge-generating drugs or anions to the membrane.
Potentiation of developing neuromuscular synapses by the neurotrophins NT-3 and BDNF

THE neurotrophins are a family of neurotrophic factors that promote survival and differentiation of various neuronal populations1,2. Although the long-term effects of neurotrophins on neuronal survival and differentiation have been intensively studied, nothing is known about their effects on synaptic function. Here we report that acute exposure to neurotrophin-3 (NT-3)3,4 or brain-derived neurotrophic factor (BDNF)5, but not nerve growth factor (NGF)6, rapidly potentiates the spontaneous and impulse-evoked synaptic activity of developing neuromuscular synapses in culture. The effect appears to be presynaptic in origin and to be mediated by the Trk family of receptor tyrosine kinases7. These results provide evidence for the regulation of the function of developing synapses by neurotrophins.
Flying between obstacles with an autonomous knife-edge maneuver

We develop an aircraft and control system that is capable of repeatedly performing a high speed (7m/s or 16 MPH) "knife-edge" maneuver through a gap that is smaller than the aircraft's wingspan. The maneuver consists of flying towards a gap, rolling to a significant angle, accurately navigating between the obstacles, and rolling back to horizontal. The speed and roll-rate required demand a control system capable of highly precise, repeatable maneuvers. We address the necessary control theory, path planning, and hardware requirements for such a maneuver, and give a proposal for a new system that may improve upon the existing techniques.
Magma: A potential source of fuels

Magma and hot silicate rocks can be used to produce fuels from aqueous fluids. Fuel generation from injection of aqueous fluids into magmatic environments occurs principally because the FeO content of these systems causes them to be relatively reducing. Thermodynamic and experimental studies indicate that fluids containing 3 mole hydrogen would result from the interaction of water with typical basaltic rock or magma over the temperature range 500 to 1300{sup 0}C at 100 MPa total pressure. The cumulative hydrogen potentially recoverable from the interaction of water with a cubic kilometer of basalt at these conditions is on the order of 10{sup 12} moles (2 x 10{sup 12} grams or 20 km{sup 3} at S.T.P.). Fuel concentrations can be considerably enhanced by the addition of biomass to the injected aqueous fluid. The mid-ocean ridge systems appear to offer the most favorable site for magmatic fuel generation.
AP/HTPB laminate propellant flame structure: Fuel-lean intrinsic instability

Abstract Two-dimensional laminate propellant flames of ammonium perchlorate (AP) and hydroxyl-terminated polybutadiene (HTPB) have been observed using infrared (IR) and ultraviolet (UV) emission and transmission imaging. Under fuel-lean conditions and at slightly elevated pressures (4 atm), intrinsic instability has been observed in the form of a leading-edge flame kernel whose location oscillates laterally about the central fuel binder layer. A mechanistic explanation for this behavior is described in terms of local gas-phase equivalence ratio, surface geometry, and gas–solid thermal coupling. The flame structure under these conditions is unique in having a leading-edge flame kernel that appears to be more spatially distinct from the trailing diffusion flame than under nonoscillatory conditions. Other results are reported, including gas-phase rotational and vibrational temperature estimates based on HCl emission imaging spectroscopy. These results add to a growing set of flame and burning surface observations being assembled for the purpose of comprehensive validation of multi-dimensional AP composite propellant computational combustion models.
Copper dissociation as a mechanism of fungal laccase denaturation by humic acid

Effects of humic acid on removal of hydroxy polychlorobiphenyls (PCBs) with laccase from Trametes versicolor were studied. In the absence of humic acid, hydroxy PCBs were rapidly degraded by laccase. However, the rate constants decreased with increasing humic acid concentration, the reactions being completely inhibited at 150 mg l-1 of humic acid. Peroxidase from Arthromyces ramosus was not inhibited by the same treatment. The activity of humic acid-deactivated laccase was completely restored by copper ions (500 μM of Cu2+ in 150 mg l-1 of humic acid), but not by other metal ions (Zn2+, Fe2+ and Hg2+). Humic acid-deactivated laccase purified by gel permeation chromatography (GPC) showed no activity against 2,2′-azino-bis(3-ethylbenzthiazoline sulfonic acid) diammonium salt and 3,5-dichloro-4-hydroxybiphenyl, but its activity was restored by copper ion treatment. Humic acid-deactivated laccase showed similar properties, such as GPC retention time and copper ion requirements for activity, to those of laccase deactivated by nitrilotriacetic acid. The extent of humic acid inhibition, expressed as activity non-recoverable by copper ion treatment, increased over time more rapidly than that of the humic acid-free control. These results suggest that short-term inactivation of laccase, i.e., less than 1 day, is attributable to a depletion of copper ion.
A new group of food colorants.

Abstract The development of foods with an attractive appearance is an important goal in the food industry. This often means the addition of a colorant, which can be accompanied by the addition of nutrients to help to improve public health. There is recently a worldwide movement towards more use of natural colorants. The anthocyanins are one of many groups of natural pigments; they are well established because of their availability as by-products of the wine industry. A recently discovered group of acylated B-ring-substituted anthocyanins show particular promise for use as colorants because they are more stable and show increased coloration at pH values of 4.0–5.5, where conventional anthocyanins are nearly colorless.
Influence of copolymer composition on non‐fickian water transport through glassy copolymers

The dynamic swelling behavior of poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) and poly(2-hydroxyethyl methacrylate-co-N-vinyl-2-pyrrolidone) in water was followed at 37°C. The results were analyzed in terms of a simple non-Fickian transport equation, which expresses the fractional penetrant uptake as an exponential function of the diffusion time. The exponent n, which indicates Fickian or non-Fickian transport mechanism, was correlated to the content of the more hydrophilic component of the copolymer. Photomicrographs obtained with polarized light offer new information about the position and movement of the penetrant front in glassy, hydrophilic polymers.
Direct synthesis of metallocarborane complexes via metal atom or organometallic reagents

Abstract Both metal atom and organometallic reagents have been used for the direct synthesis of various metallocarborane clusters without the prior synthesis of the carborane system. As examples, the reaction of cyclopentadiene, pentaborane(9) and 2-butyne with cobalt atoms and the reaction of 2-butyne and pentaborane(9) with (η-C 5 H 5 )Co(CO) 2 are reported.
RATINGS OF GERMAN PERSONAL NAMES AND E, P AND A

A series of three pretests and three tests were carried out at the University of Kiel, Federal Republic of Germany, to evaluate the affective meanings of 108 first names, second names, and name com...
Modification of Spectrum of Tungsten Filament Quartz-Iodine Lamps due to Iodine Vapor

The iodine atmosphere in typical quartz–iodine lamps modifies the spectrum of the emitted light by selective absorption in a broad band in the green-yellow region. Results of a study of the spectral emission of a series of quartz–iodine lamps with different amounts of iodine are given.
Investigations into transition-state geometry in the Mukaiyama directed aldol reaction.

A model compound was de- signed to study the relative orientation of enol silane and carbonyl moieties in the Mukaiyama aldol reaction.The cyclization must proceed with either a synclinal or an antiperiplanar orienta- tion of the aldehyde with respect to the enol silane.These two orientations lead to diastereomeric products, thus allow- ing for unambiguous correlation be- tween product configuration and transi- tion-state geometry.As steric bias is minimal, the product distribution should reflect the intrinsic preferences for reactant geometry in the transition state.Cyclizations of the model com- pound showed a modest preference for reaction via an antiperiplanar (open transition state) orientation of reac- tants in the presence of a wide range of Lewis acids (TiCl4, SnCl4, SnCl2, BF3·OEt2, TMSBr, trityl perchlorate, EtAlCl2) and triflic acid.The cycliza- tions promoted by tin(II) salts were syn-selective and dependent on the nature of the counterion.Fluoride ion promoted reactions were anti-selective and were independent of the nature of the cation.
Correspondence: Education for systems practice

This paper presents a discussion of the requirements of training for systems praxis, indicating the system theories, epistemologies, and choice making skills that are needed for work in social change. It is proposed that a person working with social systems must recognize that the client systems will be using not only contemporary but many earlier forms of system thinking. Similarly, it is argued that the epistemologies we are using today do not support systemic thinking and modes of change. An alternative epistemology is proposed. A professional program leading to a doctorate in Human and Organizational Systems is described which is based on training in analysis, synthesis and choice. The program has been designed to be self-reflective, employing systemic modes of learning for planning and executing systemic change.
Hybrid nanoparticle architecture for cellular uptake and bioimaging: direct crystallization of a polymer immobilized with magnetic nanoparticles on carbon nanotubes

We describe here the success of an innovative approach of direct immobilization of magnetic nanoparticles (MNPs) onto carbon nanotubes (CNTs). The approach involved functionalization of magnetic nanoparticles and consequent covalent linkage to a copolymer (PE-b-PEG). Next, the immobilized magnetic nanoparticles on the copolymer were directly crystallized on the long axis of CNTs, where the interfacial adhesion comes from electrostatic and van der Waals interaction. The intracellular trafficking of a hybrid nanoparticle system [(PE-b-PEG)–MNP–CNT–FITC] in HeLa cells was monitored using a fluorescent marker, FITC, conjugated to the nanoparticle system. The distribution of the nanoparticle system inside cells was studied by fluorescence microscopy in a time and dose dependent manner, and it was observed that the nanoparticles are located in the cytoplasm and no apparent cell death was observed at the concentration studied. Also, the effect of an externally applied magnetic field on actin cytoskeleton, cell morphology and intracellular uptake of iron was studied. The approach described here is promising for simultaneous imaging and monitoring intracellular uptake.
Down-regulation of the alpha-2C adrenergic receptor: involvement of a serine/threonine motif in the third cytoplasmic loop.

The mechanisms by which alpha-2 adrenergic receptors are down-regulated following chronic exposure to agonist are not well understood. Interestingly, the human alpha-2C receptor does not down-regulate, whereas the opossum alpha-2C receptor does down-regulate. A comparison of the amino acid sequence of the third intracellular loop of these two receptors shows that the opossum alpha-2C receptor contains a potential G protein-coupled receptor kinase (GRK)phosphorylation motif (EESSTSE) with four hydroxyl residues, whereas the human alpha-2C receptor motif only contains two hydroxyl residues (DESSAAAAE). Because a similar acidic serine-rich motif (EESSSSD) in the human alpha-2 adrenergic receptor has been demonstrated to be phosphorylated by GRK and all four serines are required for desensitization of the receptor, we sought to determine whether the EESSTSE sequence was involved in the down-regulation of the alpha-2C adrenergic receptor. Site-directed mutagenesis was used to mutate the opossum alpha-2C receptor to SSVA and AAVA in place of the SSTS wild-type sequence. Down-regulation experiments on CHO cells transfected with the receptors demonstrated that neither of the mutated receptors down-regulated following 24 h exposure to norepinephrine, whereas the wild-type receptor down-regulated to 65 ± 10% of the control. These results indicate that a motif with four hydroxyl amino acid residues in an acidic environment is important for down-regulation of the opossum alpha-2C adrenergic receptor. Because these are potential GRK phosphorylation sites, we suggest that GRK phosphorylation may be involved in alpha-2C adrenergic receptor down-regulation.