cssi/SciSciGPT-SciSciNet huggingface dataset:
Comparing knowledge tracing and performance factor analysis by using multiple model fitting procedures

Student modeling is very important for ITS due to its ability to make inferences about latent student attributes. Although knowledge tracing (KT) is a well-established technique, the approach used to fit the model is still a major issue as different model-fitting approaches lead to different parameter estimates. Performance Factor Analysis, a competing approach, predicts student performance based on the item difficulty and student historical performances. In this study, we compared these two models in terms of their predictive accuracy and parameter plausibility. For the knowledge tracing model, we also examined different model fitting algorithms: Expectation Maximization (EM) and Brute Force (BF). Our results showed that KT+EM is better than KT+BF and comparable with PFA in predictive accuracy. We also examined whether the models' estimated parameter values were plausible. We found that by tweaking PFA, we were able to obtain more plausible parameters than with KT.
Thermal Tolerance, Range Expansion, and Status of Tropical Amphibians: Reply to Catenazzi

We thank Catenazzi for his extensive discussion of temperature constraints of tropical amphibians and agree that many factors constrain their movement. Indeed, our paper details them.
Upper atmospheric nomenclature: Addendum to Section 11

Abstract The name turbosphere is proposed for the region from the ground upwards, in which turbulent mixing is more powerful than diffusion. The upper limit of the turbosphere, the turbopause, may or may not be the same as the homopause.
51 - The Earth's Interior

This chapter outlines some of the understanding of the Earth's interior derived from seismology. The most fundamental approach to gleaning Earth structure from seismic waves is to measure arrival times of ground vibrations as a function of distance from the source. Seismograms from distant earthquakes are characterized by a sequence of discrete body wave arrivals followed by dispersed surface wave trains. Body wave travel-time analysis is often considered as a primary tool for studying Earth structure. However, complete waveform analysis allows even more information to be gleaned from seismic recordings, and has unraveled the complex interference effects involved in surface waves and normal modes. Earth's crust is the most important region of the interior, providing the environment, natural resources, and geological hazards that affect humanity. The complexity of structure and geological history of the continental crust are largely apparent from surface observations that provide important clues in the efforts to understand Earth's interior.
The design of a mobile radio receiver using a direct conversion architecture

The authors outline the advantages of building a mobile radio receiver using a direct downconversion architecture rather than the conventional heterodyne approach. Design problems particular to mobile radio direct-conversion receivers, such as achieving good sensitivity and dynamic range, are discussed and solutions proposed. The integrated approach taken to the design of the RF mixers, the subsequent low-frequency amplifier, and active filter is detailed. This allows low conversion loss and high output impedance mixers to be designed, amplifiers with low noise performance over the DC to BW/sub RF//2 bandwidth to be constructed, and filters that set selectivity without impacting the signal-to-noise ratio at their output to be specified. Design advantages that are a direct consequence of this choice of receiver architecture, such as high selectivity, small size, and lower power consumption, are detailed. Finally, the authors describe the receiver implementation and characterize its performance. >
SIFT: a tool for wide-area information dissemination

The dissemination model is becoming increasingly important in wide-area information system. In this model, the user subscribes to an information dissemination service by submitting profiles that describe his interests. He then passively receives new, filtered information. The Stanford Information Filtering Tool (SIFT) is a tool to help provide such service. It supports full-text filtering using well-known information retrieval models. The SIFT filtering engine implements novel indexing techniques, capable of processing large volumes of information against a large number of profiles. It runs on several major Unix platforms and is freely available to the public. In this paper we present SIFT's approach to user interest modeling and user-server communication. We demonstrate the processing capability of SIFT by describing a running server that disseminates USENET News. We present an empirical study of SIFT's performance, examining its main memory requirement and ability to scale with information volume and user population.
Genetics of subthalamic nucleus in development and disease

The subthalamic nucleus (STN) is a crucial node in the basal ganglia. Clinical success in targeting the STN for deep brain stimulation in Parkinson's disease patients has prompted increased interest in understanding STN biology. In this report, we discuss recent evidence for transcription factor mediated regulation of STN development. We also review STN developmental neurobiology and known patterns of gene expression in the developing and mature STN.
Auger anisotropy: A probe of doubly excited product states

Abstract Energy and spatial distributions of Auger electrons emitted from products of ion/atom collisions can reveal the identity and character of states created by excitation, inner shell ionization or multi-electron transfer. When coupled with coincident detection of projectile scattering, one can obtain a near “complete” experiment, i.e. the scattering angle dependence of complex magnetic substate amplitudes. Such results challenge theory at the finest level of detail. This report summarizes progress made in the study of double electron capture in measurements of this kind.
Respiratory Failure Treated with the Membrane Oxygenator in the Hyperbaric Chamber : Part I: Studies in Dogs during Total Asphyxia at Three Atmospheres Absolute (ATA)

Because of the availability of the hyperbaric chamber for the treatment of patients with intractable acute respiratory disease, many patients have been sent from other institutions to The Mount Sinai Hospital. Some of these patients were salvaged but many died, either because oxygen toxicity of the respiratory tract was superimposed on the original lesion, or because there was insufficient functioning lung tissue to provide adequate oxygenation even under hyperbaric conditions. It became apparent that the only likely source of support for this terminal group of patients would be an extracorporeal oxygenator or “artificial lung.” Utilizing the Peirce membrane oxygenator, a Hufnagel pneumatic pump, hemodilution prime and veno-venous perfusion with flow rates of 30 to 40 ml/kg/min it was possible at three atmospheres absolute (ATA) to keep apneic dogs alive for one hour. Of seven dogs studied, six survived, and one died at the termination of the experiment because of hypovolemic shock. Average oxygen tensions of the arterial blood after 5, 20, 40 and 55 minutes of apnea were 570, 369, 234 and 92 mm Hg respectively. Carbon dioxide tensions increased progressively and pH declined. Average plasma hemoglobin at the start of perfusion was 35.5 mg percent and at the end 36.2 mg percent. Length of perfusion varied from 2½ to 4½ hours.
Isotherms for the He-Ar system at 50°C, 0°C and -50°C up to 700 atm

Abstract A Burnett apparatus was constructed and used to obtain compressibility factors and virial coefficients for helium, argon, and four mixtures at 50°C, 0°C and -50°C. Pressures ranged from 3 to 700 atm. The standard deviations of the compressibility factors ranged from 0.06% at the highest pressures to 0.001% at the lowest pressures.
Polymer characterization by combining liquid chromatography with MALDI and ESI mass spectrometry.

High-performance polymers are complex mixtures of materials of different size and chemical composition and with different end groups and architecture. To determine the molecular heterogeneity of such systems, hyphenation of several techniques is required. The value of coupling mass spectrometry (MS) with separation techniques has already been recognized – such methods have proved to be among the most powerful for molecular characterization of complex polymer systems. The review focuses on matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI) MS coupled with liquid chromatography (LC). Such hyphenation has been used for most polymer analysis by mass spectrometry coupled with separation techniques. The advantages and/or limitations of these techniques for polymer characterization are discussed. Future prospects are briefly outlined.
Space simulation for spacecraft autopilot systems.

Interplanetary spacecraft autopilot simulation tests during rocket motor firing in space environment
Follicle aspiration, sperm injection, and assisted rupture (FASIAR): a simple new assisted reproductive technique.

Abstract Objective: To describe the first successful application of a new fertility-enhancing technique. Design: Case report. Setting: Academic fertility program. Patient(s): A 36-year-old nulligravid woman undergoing inseminations with frozen-thawed donor sperm. Intervention(s): Ovarian superovulation, follicle aspiration, sperm injection, and assisted follicular rupture. Main Outcome Measure(s): Assessment of feasibility of technique and pregnancy outcome. Result(s): After failing to conceive during 16 cycles of IUI, the patient successfully achieved an ongoing pregnancy during the second follicle aspiration, sperm injection, and assisted rupture (FASIAR) attempt. Conclusion(s): Follicle aspiration, sperm injection, and assisted rupture combines the concepts of superovulation, IUI, and peritoneal oocyte and sperm transfer to obviate the possibility of luteinized unruptured follicle syndrome, assist oocyte release, and ensure gamete intermixing. It also can be used to reduce the number of ovulating oocytes and thus to reduce the risk of multiple gestations. Follicle aspiration, sperm injection, and assisted rupture is a new, simple, office-based procedure that does not require embryologic expertise beyond sperm preparation as for IUI, yet promises to be more successful than IUI.
Depression of plasma lipid fractions and inhibition of platelet aggregation by action of glucagon.

Abstract Venous blood was taken from 20 normal people following an overnight fast, and glucagon (1 mg) dissolved in 1.0 ml diluent was given i.v. Blood was taken at 1, 2, and 3 hr. Control studies were done in seven of the subjects at another time by administering the diluent only. Glucagon caused significant depression of plasma total lipid, and triglyceride at 1 and 2 hr, while plasma total cholesterol was significantly depressed at 2 hr. Epinephrine-induced platelet aggregation was studied in the hourly specimens of platelet-rich plasma (PRP) by measuring change in optical density (OD). Epinephrine caused both primary and secondary platelet aggregation in the 0-hr PRP of ten subjects and primary aggregation only in the other ten. Intravenous glucagon caused significant inhibition of secondary platelet aggregation at 2 and 3 hr. Secondary platelet aggregation was not inhibited when there was no depression of plasma lipids following glucagon (two of ten subjects). Glucagon (1 mg) dissolved in 1.0 ml diluent was given subcutaneously to five of the subjects at another time, and the studies were repeated. Depression of plasma total lipid, triglyceride, and cholesterol was greater than when glucagon was given i.v. Magnitude and duration of the depression were both increased. Secondary platelet aggregation induced by epinephrine was also inhibited. It was concluded that depression of plasma lipids by transfer of the lipid to platelets by action of glucagon is associated with inhibition of epinephrine-induced platelet aggregation.
Musical creativity: insights from music education research

Musical creativity: insights from music education research, edited by Oscar Odena, Surrey, Ashgate Press, 2012, 246 pp., £50.00 (hardback), ISBN 978-1-4094-0622-8 The study of creativity is in vogu...
Early diagnosis to enable early treatment of pre-osteoarthritis

Osteoarthritis is a prevalent and disabling disease affecting an increasingly large swathe of the world population. While clinical osteoarthritis is a late-stage condition for which disease-modifying opportunities are limited, osteoarthritis typically develops over decades, offering a long window of time to potentially alter its course. The etiology of osteoarthritis is multifactorial, showing strong associations with highly modifiable risk factors of mechanical overload, obesity and joint injury. As such, characterization of pre-osteoarthritic disease states will be critical to support a paradigm shift from palliation of late disease towards prevention, through early diagnosis and early treatment of joint injury and degeneration to reduce osteoarthritis risk. Joint trauma accelerates development of osteoarthritis from a known point in time. Human joint injury cohorts therefore provide a unique opportunity for evaluation of pre-osteoarthritic conditions and potential interventions from the earliest stages of degeneration. This review focuses on recent advances in imaging and biochemical biomarkers suitable for characterization of the pre-osteoarthritic joint as well as implications for development of effective early treatment strategies.
Tandem annulations. 2-bromomethyl-3-(trimethylsilylmethyl)buta-1,3-diene as a synthon for a zwitterion of 2,2'-biallyl

Abstract Alkylation of an enolate with the titled conjunctive reagent followed by cyclization of the allylsilane moiety onto the carbonyl group effects the first annulatiion; the resultant 2,3-dimethylene-cyclohexane participates in a subsequent Diels-Alder reaction to complete the second annulation.
Development of an explicit multiblock/multigrid flow solver for viscous flows in complex geometries

A new computer program is being developed for doing accurate simulations of compressible viscous flows in complex geometries. The code employs the full compressible Navier-Stokes equations. The eddy viscosity model of Baldwin and Lomax is used to model the effects of turbulence on the flow. A cell centered finite volume discretization is used for all terms in the governing equations. The Advection Upwind Splitting Method (AUSM) is used to compute the inviscid fluxes, while central differencing is used for the diffusive fluxes. A four-stage Runge-Kutta time integration scheme is used to march solutions to steady state, while convergence is enhanced by a multigrid scheme, local time-stepping, and implicit residual smoothing. To enable simulations of flows in complex geometries, the code uses composite structured grid systems where all grid lines are continuous at block boundaries (multiblock grids). Example results shown are a flow in a linear cascade, a flow around a circular pin extending between the main walls in a high aspect-ratio channel, and a flow of air in a radial turbine coolant passage.
Videotape-based decision aid for colon cancer screening. A randomized, controlled trial.

Background Rates of colon cancer screening in the United States are low, in part because of poor communication between patients and providers about the availability of effective screening options. Objective To test whether a decision aid consisting of an educational video, targeted brochure, and chart marker increased performance of colon cancer screening in primary care practices. Design Randomized, controlled trial. Setting Three community primary care practices in central North Carolina. Patients 1657 consecutive adult patients 50 to 75 years of age were contacted. Of these, 651 (39%) agreed to participate; 249 of the 651 participants (38%) were eligible. Eligible patients had no personal or family history of colon cancer and had not had fecal occult blood testing in the past year or flexible sigmoidoscopy, colonoscopy, or barium enema in the past 5 years. Intervention The 249 participants were randomly assigned to view an 11-minute video about colon cancer screening (intervention group) or a video about automobile safety (control group). After viewing the video, intervention group participants chose a color-coded educational brochure (based on stages of change) to indicate their degree of interest in screening. A chart marker of the same color was attached to their charts. Controls received a generic brochure on automobile safety, and no chart marker was attached. Measurements Frequency of screening test ordering as reported by participants and frequency of completion of screening tests as verified by chart review. Results Fecal occult blood testing or flexible sigmoidoscopy was ordered for 47.2% of intervention participants and 26.4% of controls (difference, 20.8 percentage points [95% CI, 8.6 to 32.9 percentage points]). Screening tests were completed by 36.8% of the intervention group and 22.6% of the control group (difference, 14.2 percentage points [CI, 3.0 to 25.4 percentage points]). Conclusion A decision aid consisting of an educational video, brochure, and chart marker increased ordering and performance of colon cancer screening tests.
Successful Robot-Assisted Repair of Congenital Mitral Valve Regurgitation

Congenital mitral valve regurgitation (CMR) is very uncommon in adults and is usually associated with other congenital malformations. Repair of the mitral valve remains the standard of care. Very limited reports are available on minimally invasive surgical approaches in treating CMR. This report represents the first case series of the successful application of robotics in correcting CMR and associated anomalies, including a partial atrioventricular canal defect.
Endogenous electrical current leaves the limb and prelimb region of the Xenopus embryo

Abstract The electrical current pattern around the developing Xenopus laevis embryo was mapped with a vibrating probe. Current (taken as the movement of positive charge) was found to leave the emerging hind limb bud and to enter the gill region of the stage 47 embryo. The magnitude of the current leaving the limb was about 7 μA/cm 2 and the current entering the gill was about 60 μA/cm 2 . Other regions of smaller outward current were found between the limb and gill. At stage 43, prior to the appearance of the limb bud, a highly localized region of outward current existed in the general area from which the bud would later emerge. The inward current was localized to the gill bud, as in the older embryo. The ionic basis of the currents could not be determined. In about one-third of the cases studied, the inward current was sodium sensitive since the removal of external sodium or the addition of amiloride reversably blocked the current. In the remaining cases, however, removal of sodium did not change (or else increased) the current. No other external ion (Ca 2+ , Mg 2+ , K + ) could be identified as the current-carrying ion; the possibility of an outward movement of some anion such as Cl − or HCO − 3 remains.
Detection of an antigen specific for proventricular dilation disease in psitticine birds

PROVENTRICULAR dilation disease (pdd) affects many species of birds, especially large psittacines such as macaws ([Gregory 1994][1]). The classical presenting sign is paralysis and dilation of the proventriculus secondary to nerve damage. pdd is believed to be caused by a virus. [Grund and others (
A Review of Neuroprotection Pharmacology and Therapies in Patients with Acute Traumatic Brain Injury

Traumatic brain injury (TBI) affects 1.6 million Americans annually. The injury severity impacts the overall outcome and likelihood for survival. Current treatment of acute TBI includes surgical intervention and supportive care therapies. Treatment of elevated intracranial pressure and optimizing cerebral perfusion are cornerstones of current therapy. These approaches do not directly address the secondary neurological sequelae that lead to continued brain injury after TBI. Depending on injury severity, a complex cascade of processes are activated and generate continued endogenous changes affecting cellular systems and overall outcome from the initial insult to the brain. Homeostatic cellular processes governing calcium influx, mitochondrial function, membrane stability, redox balance, blood flow and cytoskeletal structure often become dysfunctional after TBI. Interruption of this cascade has been the target of numerous pharmacotherapeutic agents investigated over the last two decades. Many agents such as selfotel, pegorgotein (PEG-SOD), magnesium, deltibant and dexanabinol were ineffective in clinical trials. While progesterone and ciclosporin have shown promise in phase II studies, success in larger phase III, randomized, multicentre, clinical trials is pending. Consequently, no neuroprotective treatment options currently exist that improve neurological outcome after TBI. Investigations to date have extended understanding of the injury mechanisms and sites for intervention. Examination of novel strategies addressing both pathological and pharmacological factors affecting outcome, employing novel trial design methods and utilizing biomarkers validated to be reflective of the prognosis for TBI will facilitate progress in overcoming the obstacles identified from previous clinical trials.
A cytoplasmic domain mutation in ClC-Kb affects long-distance communication across the membrane.

Background ClC-Kb and ClC-Ka are homologous chloride channels that facilitate chloride homeostasis in the kidney and inner ear. Disruption of ClC-Kb leads to Bartter's Syndrome, a kidney disease. A point mutation in ClC-Kb, R538P, linked to Bartter's Syndrome and located in the C-terminal cytoplasmic domain was hypothesized to alter electrophysiological properties due to its proximity to an important membrane-embedded helix. Methodology/Principal Findings Two-electrode voltage clamp experiments were used to examine the electrophysiological properties of the mutation R538P in both ClC-Kb and ClC-Ka. R538P selectively abolishes extracellular calcium activation of ClC-Kb but not ClC-Ka. In attempting to determine the reason for this specificity, we hypothesized that the ClC-Kb C-terminal domain had either a different oligomeric status or dimerization interface than that of ClC-Ka, for which a crystal structure has been published. We purified a recombinant protein corresponding to the ClC-Kb C-terminal domain and used multi-angle light scattering together with a cysteine-crosslinking approach to show that the dimerization interface is conserved between the ClC-Kb and ClC-Ka C-terminal domains, despite the fact that there are several differences in the amino acids that occur at this interface. Conclusions The R538P mutation in ClC-Kb, which leads to Bartter's Syndrome, abolishes calcium activation of the channel. This suggests that a significant conformational change – ranging from the cytoplasmic side of the protein to the extracellular side of the protein – is involved in the Ca2+-activation process for ClC-Kb, and shows that the cytoplasmic domain is important for the channel's electrophysiological properties. In the highly similar ClC-Ka (90% identical), the R538P mutation does not affect activation by extracellular Ca2+. This selective outcome indicates that ClC-Ka and ClC-Kb differ in how conformational changes are translated to the extracellular domain, despite the fact that the cytoplasmic domains share the same quaternary structure.
On the entropic perturbation and exponential penalty methods for linear programming

This note points out that the recently proposed exponential penalty approach to linear programming is identical to the well-known entropic perturbation approach. The primal and dual trajectories provided by these two approaches are shown to be equivalent.
High-Lamellar Ordering and Amorphous-Like π-Network in Short-Chain Thiazolothiazole−Thiophene Copolymers Lead to High Mobilities

Owing to their superior transport properties, poly(alkylthiophenes) and their derivatives emerged as one of the most widely studied semiconducting polymers with potential applications in organic electronics. It is now generally acknowledged that one of the particularly effective ways to increase the carrier mobility in these materials is by increasing the length of the conjugated backbones. Some recent reports suggest also that carrier mobilities can be further enhanced by highly crystalline arrangement (and interdigitation) of alkyl side chains possibly because it promotes the formation of extensive layered structures favorable for carrier transport. Results presented here demonstrate that, surprisingly, none of these factors are actually necessary for good electronic performance of polythiophene-like systems. Thiophene-based semiconducting polymers bearing thiazolothiazole unit (PTzQT) described here were shown to have very high carrier mobilities (∼0.3 cm2/Vs) despite their low molecular weight and une...
Annual and regional variation in mercury concentrations in wood stork nestlings.

Mercury concentrations were measured in blood, down, and feathers from approximately 300 wood stork nestlings in one South Carolina, USA, and four Georgia, USA, colonies from 1996 to 1999. Coastal nestlings generally had lower mercury concentrations than those from inland colonies. Interyear differences were also apparent, particularly for coastal colonies, where nestling mercury concentrations were higher in 1998 than in 1997 or 1999. In 1998, a wet winter followed by a dry spring and summer produced ideal freshwater foraging conditions and mercury concentrations in coastal nestlings were higher than during the two dry years. There was little interyear variation in mercury concentrations in nestlings from inland colonies, as parent storks from these colonies forage exclusively in freshwater habitats regardless of rainfall patterns. These results suggest that greater risk of mercury exposure to nestlings is associated with use of freshwater foraging habitats.
Studying family participation in system-of-care evaluations: using qualitative methods to examine a national mandate in local contexts.

With the rapid pace of policy and practice changes in children’s mental health, there is a need for research to examine, describe, and disseminate information about the translation of policy directives into practice innovations at the local level. National policy mandates for children’s mental health have placed expectations on local communities to involve families as partners in the development, implementation, and evaluation of systems of care with little guidance about how to implement program requirements locally. Consequently, there is a gap in the knowledge base regarding how innovations are actually implemented in local community contexts. This article reports on a qualitative study to gain understanding of family participation in evaluations of systems of care from the perspectives of evaluators and family members working together. Findings provided rich examples of the experiences and perceptions of evaluators and family members working on evaluation teams, the challenges they encountered, and effective strategies to meet those challenges.
Eosinophilia in rats infected with Trichinella spiralis

Abstract Infection of young adult male Holtzman rats with 4,000 Trichinella spiralis larvae initiated a moderate leucocytosis as early as the first post-infection day. This elevation of the white cell count was observed in 9 of the 10 post-infection days studied. A rise in circulating eosinophiles which was first noted on the fifth post-infection day persisted through post-infection days 6, 7, 8, 9 and 10. The rise in eosinophiles was statistically significant on days 5, 6, 8, 9 and 10.
Attenuation of sound in ducts with acoustic treatment—a generalized approximate equation

A generalized approximate equation for duct lining sound attenuation is presented. The specification of two parameters, the maximum possible attenuation and the optimum wall acoustic impedance, is shown to completely determine the sound attenuation for any acoustic mode at any selected wall impedance. The equation is based on the nearly circular shape of the constant attenuation contours in the wall acoustic impedance plane. For impedances far from the optimum the equation reduces to Morse's approximate expression. The equation can be easily used for initial acoustic liner design. Not least important is the illustrative nature of the solutions which provide an understanding of the duct propagation problem which is usually obscured in the exact calculations. An additional property of the approximate equation is that empiricism can be injected into the expression to account for phenomena which can not currently be handled by exact analysis. The peak and the bandwidth of the sound attenuation spectrum are presented by quite simple functions of the ratio of actual wall acoustic resistance to optimum resistance.
Large-Scale Vertical Eddy Diffusion in the Main Pycnocline of the Central North Pacific

Abstract Indirect procedures are used to estimate the latitudinal distribution of the large-scale vertical eddy diffusivity coefficient in the main pycnocline from the interannual change in Tθ, ρθ structure of the water column in the central midlatitude North Pacific from 35–44°N, 150–170°W. Using T, S data from two identical hydrographic surveys, one made in June 1976 and the other in May 1977, the interannual change in potential temperature is recorded on three potential density surfaces (i.e., ρθ = 26.6, 27.0 and 27.2) that lie in the upper, middle and lower part of the main pycnocline, respectively. By relating these interannual changes to the vertical gradients of the average potential temperature on each surface (i.e., through the heat conservation equation), the large-scale vertical eddy diffusivity coefficient and its vertical gradient were determined by least-squares estimate procedures. The vertical eddy diffusivity coefficient K is found to have been positive over the entire region, with magnit...
Ambient infrasound noise

[1] The ambient infrasound noise environment is characterized for 21 globally distributed infrasound arrays in the frequency band of 0.03 to 7 Hz. Power Spectral Density (PSD) is measured for one site of each array for 21 intervals at each of four times of day from January 2003 through January 2004. The ambient noise at infrasound stations is highly variable by season, time of day and station. Noise spectra for an individual station may vary by four orders of magnitude at any given frequency. Preliminary infrasound noise models are defined, which can be used as baselines for evaluating ambient noise at current and new infrasound stations. Median noise levels in the microbarom band centered on 0.2 Hz vary smoothly in an annual pattern, with most stations observing maximum noise during local winter. Noise amplitudes do not have a normal or log-normal distribution, but rather are skewed to larger amplitudes.
Singularities in the Unphysical Sheets and the Isobar Model

Scattering amplitudes involving two- and three-particle states are continued across the inelastic section of the unitarity cut, and the singularities in the unphysical sheets thus reached are determined. Associated with an unstable particle is a complex unitarity cut, through which we further continue into another unphysical sheet. Dynamical singularities associated with a Born-type diagram for the three-particle scattering amplitude are found to be present in the elastic scattering and the production amplitudes also because of the coupling by unitarity. These singularities are isolated from the physical region by the complex unitarity cut and thus cannot be directly responsible for any resonance phenomenon. However, if the interaction force is favorable, a resonance pole can occur in a different Riemann sheet in the vicinity of these singularities. This resonance pole is directly accessible from the physical region and can therefore give rise to a resonance.
Observation of narrow resonances in the H - photodetachment cross section near the n=3 threshold

Two pronounced dips in the ${\mathrm{H}}^{\ensuremath{-}}$ photodetachment cross section have been observed at photon energies of 12.650\ifmmode\pm\else\textpm\fi{}0.004 and 12.837\ifmmode\pm\else\textpm\fi{}0.004 eV, just below the hydrogenic $n=3$ threshold. These energies were reached by crossing a uv laser beam with a relativistic ${\mathrm{H}}^{\ensuremath{-}}$ beam. The dips are interpreted as the first two members of a $^{1}P$ Feshbach resonance series, of the "+" type, converging on $n=3$. Fano line shapes have been fitted to these structures to extract their intrinsic widths and line profile indices.
Extraction and precipitation chemistry for mercury recovery from aqueous wastes

Abstract This paper describes an extraction-precipitation process to recover mercuric chloride from aqueous solutions. The process is a modification of a dicarboxylic acid recovery process that exploits the enhanced solubility of mercuric chloride in organic solvents loaded with water. Mercuric chloride in ethyl acetate has a solubility enhancement of 1.34 moles mercuric chloride per mole of water added to the solvent, consistent with previously reported phase behavior. Solubility enhancement is also reported for formates, in contrast to previously reported results. For example, propyl formate showed 2.91 moles mercuric chloride per mole water enhancement. The modified process described in this paper relies on (1) favorable liquid-liquid equilibrium (mercuric chloride distribution into ethyl acetate or into propyl formate), (2) favorable liquid-solid equilibrium with enhanced solute solubility on addition of a minor constituent (water), and (3) preferential vaporization of the minor constituent from the s...
The Force of Natural Selection

Jacob Goldenberg et al. (“Creative sparks,” Essays on Science and Society, Science's Compass, 3 Sept., p. [1495][1]) discuss the nature of creativity. They dispel the notion that total freedom is necessary for the creative process. The authors state that while randomness is of value, a structured process is the key to creativity. I agree with their assessment, but would like to suggest that this is the very essence of the evolution of life. Life is a structured process that evolves through accumulation of random (although limited) mutations. It is subject to judgment by the force of natural selection rather than a panel of experts. The products of this creative process are all the myriad forms of life, past and present. Consistent with the authors' idea that regularities can serve as an infrastructure for generating creative ideas, most life forms are built up from some regular plan or framework (for example, radial symmetry in echinoderms). The authors conclude that we must reappraise our fundamental approaches to creativity. Perhaps we can learn something about creative processes by studying evolution. [1]: /lookup/doi/10.1126/science.285.5433.1495
Processes responsible for the compositional structure of the thermosphere

The relative importances of the various physical and chemical mechanisms that force changes in neutral thermospheric composition for a given geophysical situation were quantified using a diagnostic postprocessor analysis package in conjunction with runs of the NCAR thermospheric general circulation model (TGCM) that was extended to include the terms of the neutral composition equation. New information was obtained on the causal mechanisms responsible for changes in the concentrations of the three neutral species, O2, O, and N2, whose time-dependent mass mixing ratios were calculated within the TGCM. Principal results calculated for F-region altitudes are described, and thermospheric compositions calculated using the NCAR-TGCM model are compared with the predictions of the empirical thermospheric model of Hedin (1987).
Extent of post-transcriptional level control of protein synthesis in the absence of cell division

Abstract Major changes in the pattern of synthesis of soluble and insoluble proteins occur even in the absence of transcription (with actinomycin D) in sea urchin embryos prior to blastulation. These changes also occur in the presence of colchicine or Colcemid. Cell division does not therefore seem to be a prerequisite for post-transcriptional control of protein synthesis.
Implementation of an Electronic Resource Assessment System in an Academic Library.

Purpose – The purpose of this paper is to provide a library with useful information about selection criteria for an electronic resource assessment system and practical assistance on how to implement efficiently such a system.Design/methodology/approach – The paper is based on literature review, desk research, and implementation experience.Findings – The paper identifies a number of homegrown, open‐source, and commercial electronic resource assessment systems and discusses their selection criteria. Based on the implementation of 360 Counter, the paper details the efficient way to implement the system.Originality/value – Collecting usage statistics is very important to make informed and well‐rounded collection decisions. Libraries are seeking suitable measuring tools to meet their needs. This paper reviews several electronic resource assessment systems, discusses the selection criteria and implementation process of 360 Counter, and detailed learned lessons as well. Future directions for usage statistics are...
Long-range attraction between silanated silica materials studied by an electrolyte titration with atomic force microscopy

Abstract A parametric study of electrostatic and hydrophobic forces with changing electrolyte concentration shows characteristic features in dynamic cantilever snap-in from which the hydrophobic interaction can be assessed. A relatively simple and efficient experimental procedure for determining the strength and range of the hydrophobic effect is accomplished in the sphere-plate geometry between silanated glass and quartz by a systematic electrolyte titration of electrostatic forces. Snap-in distance acquired with atomic force microscopy (AFM) plotted against electrolyte concentration shows a minimum at some identifying intermediate salinity and a snap-in plateau at high concentrations. These prominent features, distinguishable from an adequate database represented by a single titration curve, facilitate deconvolution of the hydrophobic force from other interactions. Monovalent electrolyte concentration does not appear to affect the hydrophobic interaction directly between 10 −4 and 10 −1 M, but evidence of an independent and long-range electrostatic correlation force is observed.
A non-overlapping domain decomposition method with non-matching grids for modeling large finite antenna arrays

A non-overlapping domain decomposition method (DDM) is proposed herein to solve Maxwell equations in R^3. In this work, the Maxwell equations are discretized using a vector finite element method with hierarchical H(curl) vector basis functions. There are two major ingredients in the proposed non-overlapping DDM: (a) A proper 1st order transmission condition to enforce field continuity across domain boundaries and (b) A cement technique to allow non-matching grids for neighboring domains. Moreover, a detail Fourier analysis of the transmission condition for a canonical half-space example is presented. The analysis provides significant insights into the convergence behavior of the proposed non-overlapping DDM for solving electromagnetic radiation problems, such as the large finite antenna arrays. Particularly for the antenna arrays, the proposed non-overlapping DDM is extremely efficient since the formulation can easily incorporate geometrical repetitions. Exponentially tapered notch (Vivaldi) antenna arrays with size up to 100x100 elements are solved on a common PC to validate the proposed non-overlapping DDM.
Varietal tolerance of zinc toxicity in peanuts

Abstract Peanuts (Arachishypogaea) are more susceptible to zinc (Zn) toxicity than other crops. However, there is potential for rapid evolution of Zn tolerance in many species. The objectives of this study were to test a nutrient solution screening procedure for identifying Zn tolerant cultivars and to identify plant characteristics and cultivars which have potential for Zn tolerance. Florunner was used as the test cultivar to determine the optimum Zn and pH levels for the nutrient solution cultivar screening test. The screening test showed that VA 81B and NC 6 (both virginia‐type peanuts) were more Zn sensitive than Florunner and that N. M. Valencia C and McRan (both valencia‐type peanuts) were more tolerant than Florunner. Field tests were carried out at three locations in Tift County, Georgia: Gibbs Farm (1986–87), Richards Farm (1991), and Stephens Farm (1992). Two out of four field tests did not have adequate soil Zn levels to test Zn tolerance; soil pH between 5.0 and 5.5 and Mehlich 1 soil Zn level...
Evidence against proton gradient formation being the cause of chlorophyll fluorescence quenching by N-methylphenazonium methosulfate.

Abstract In strong illumination, 3-(3,4-dichlorophenyl)-1, 1-dimethylurea (DCMU)-poisoned chloroplasts exhibit a high yield of chlorophyll fluorescence while P-700 turnover, proton uptake, and phosphorylation are inhibited and a pH gradient is undetectable. When 10 μM N- methylphenazonium methosulfate (PMS) is included, the fluorescence yield in light is substantially reduced, and when 100 μM ascorbate is also included, the yield is diminished approximately to the level in darkness. Only very slight increases in P-700 turnover and proton uptake (but no detectable pH gradient) accompany the fluorescence yield decline. When 10 μM PMS and 15 mM ascorbate are added to poisoned chloroplasts (the oxygen concentration being greatly reduced), P-700 turnover, proton uptake, the pH gradient and phosphorylation all reach high levels. In this case, the yield of chlorophyll fluorescence is low and is the same in both light and dark. Further addition of an uncoupler eliminates proton uptake, the pH gradient and phosphorylation but does not significantly elevate the fluorescence yield. From these observations we suggest that, in DCMU-poisoned chloroplasts, the fluorescence quenching with PMS occurs by a mechanism unrelated to the generation of a phosphorylation potential. With chloroplasts unpoisoned by DCMU, PMS quenches fluorescence and considerably stimulates proton uptake, the pH gradient and phosphorylation. However, in this case, PMS serves to restore net electron transport.
Bile ductules and stromal cells express hedgehog ligands and/or hedgehog target genes in primary biliary cirrhosis

Indian Hedgehog (Ihh) regulates tissue morphogenesis. Hedgehog (Hh) activity has been demonstrated in human cholangiocarcinoma and hepatocellular carcinoma lines, and in myofibroblasts and progenitors from adult rodent livers. We evaluated Hh pathway involvement in the response to biliary injury in primary biliary cirrhosis (PBC). Liver sections from 3 PBC patients and 3 controls without liver disease were studied. Immunohistochemistry was used to determine if cells that accumulate in PBC livers express Ihh or Hh-target genes including the Hh-receptor, Patched (Ptc), and the Hh-transcriptional activator glioblastoma (Gli) 2. Positive cells were further identified by costaining for cytokeratin (CK) 19, a biliary marker, or OV6, a hepatic progenitor marker. In all subjects, Gli2 and Ptc expression localized in portal areas. The numbers of Gli2- or Ptc-expressing cells/portal triad were each 10-fold greater in patients with PBC than in controls (P < 0.05). In PBC livers, some CK19(+) cells coexpressed Gli2 or Ptc. Many stromal fibroblastic cells were also Gli2(+). Strong Ihh expression was detected in most bile ductular cells. Scattered stromal cells also expressed Ihh. The number of Ihh(+) cells/portal triad was 6-fold greater in PBC livers than controls (P < 0.05). OV6(+) progenitors increased significantly in PBC livers, and some of these cells coexpressed Ihh, Ptc, and/or Gli2. Conclusion: This is the first direct evidence that noncancerous, adult human livers harbor several types of cells that produce and/or respond to Hh ligands. Such Hh-responsive cells accumulate during the fibroproliferative response to chronic cholestatic liver injury, suggesting a role for Hh signaling in this process. (HEPATOLOGY 2007;45:1091–1096.)
Software process improvement at Raytheon

Over the last eight years, Raytheon mounted a sustained effort to improve its software development processes. The author describes the organizational structure and activities that made these processes more productive and predictable while raising software quality.
Aqua-Ammonia as an Environmentally Acceptable Low Temperature Brine

In many industrial processes, cooling with brines is preferable to cooling with an evaporating refrigerant. For medium and high temperatures (above about −35°C/−30°F), aqueous solutions of calcium chloride, sodium chloride, ethylene glycol, propylene glycol, and methanol have typically been used. For very low temperatures (down to about −80°C/-110°F) halocarbon refrigerants methylene chloride and trichloroethylene have generally been used. In recent years, both methylene chloride and trichloroethylene have come under increasingly strict regulation because of their toxicity. While many plants continue to use these brines, most are searching for alternates. This study was begun in response to the needs of a plant that was replacing methylene chloride with aqueous calcium chloride. The high viscosity of the calcium chloride brine caused design and operational problems. The above-mentioned brines, as well as aqua-ammonia, polydimethylsiloxane, and d-limonene, were compared for cost, toxicity, flammability, environmental safety, and energy efficiency. The energy efficiency comparison included comparisons of heat transfer coefficient, mass flow rate, volume flow rate, frictional pressure drop, inertial pressure drop, and pumping power. The comparisons indicated that aqua-ammonia was the best choice as a replacement for methylene chloride and trichloroethylene in some temperature ranges.Copyright © 2011 by ASME
Comparative effectiveness of maxillomandibular advancement and uvulopalatopharyngoplasty for the treatment of moderate to severe obstructive sleep apnea.

Purpose To directly compare the clinical effectiveness of maxillomandibular advancement (MMA) and uvulopalatopharyngoplasty (UPPP)—performed alone and in combination—for the treatment of moderate to severe obstructive sleep apnea (OSA). Patients and Methods The investigators designed and implemented a retrospective cohort study composed of patients with moderate to severe OSA (baseline AHI >15). The predictor variable was operative treatment and included MMA, UPPP, and UPPP followed by MMA (UPPP/MMA). The primary outcome variable was the apnea-hypopnea index (AHI) measured preoperatively and 3 months to 6 months postoperatively. Other variables were grouped into the following categories: demographic, respiratory, and sleep parameters. Descriptive and bivariate statistics were computed. Results The sample was composed of 106 patients grouped as follows: MMA (n = 37), UPPP (n = 34), and UPPP/MMA (n = 35) for treatment of OSA. There were no significant differences between the 3 groups for the study variables at baseline, except for AHI. Surgical treatment resulted in a significant decrease in AHI in each group: MMA (baseline AHI, 56.3 ± 22.6 vs AHI after MMA, 11.4 ± 9.8; P Conclusion The results of this study suggest that MMA should be the surgical treatment option of choice for most patients with moderate to severe OSA who are unable to adequately adhere to CPAP.