cssi/SciSciGPT-SciSciNet huggingface dataset:
The Impact of Enso on Extratropical Low Frequency Noise in Seasonal Forecasts

This study examines the uncertainty in forecasts of the January-February-March (JFM) mean extratropical circulation, and how that uncertainty is modulated by the El Nino/Southern Oscillation (ENSO). The analysis is based on ensembles of hindcasts made with an Atmospheric General Circulation Model (AGCM) forced with sea surface temperatures observed during; the 1983 El Nino and 1989 La Nina events. The AGCM produces pronounced interannual differences in the magnitude of the extratropical seasonal mean noise (intra-ensemble variability). The North Pacific, in particular, shows extensive regions where the 1989 seasonal mean noise kinetic energy (SKE), which is dominated by a "PNA-like" spatial structure, is more than twice that of the 1983 forecasts. The larger SKE in 1989 is associated with a larger than normal barotropic conversion of kinetic energy from the mean Pacific jet to the seasonal mean noise. The generation of SKE due to sub-monthly transients also shows substantial interannual differences, though these are much smaller than the differences in the mean flow conversions. An analysis of the Generation of monthly mean noise kinetic energy (NIKE) and its variability suggests that the seasonal mean noise is predominantly a statistical residue of variability resulting from dynamical processes operating on monthly and shorter times scales. A stochastically-forced barotropic model (linearized about the AGCM's 1983 and 1989 base states) is used to further assess the role of the basic state, submonthly transients, and tropical forcing, in modulating the uncertainties in the seasonal AGCM forecasts. When forced globally with spatially-white noise, the linear model generates much larger variance for the 1989 base state, consistent with the AGCM results. The extratropical variability for the 1989 base state is dominanted by a single eigenmode, and is strongly coupled with forcing over tropical western Pacific and the Indian Ocean, again consistent with the AGCM results. Linear calculations that include forcing from the AGCM variance of the tropical forcing and submonthly transients show a small impact on the variability over the Pacific/North American region compared with that of the base state differences.
Simplified energy analysis methodology for commercial buildings

Abstract Commercial building energy analyses may be used for new building design, energy end use forecasting and energy audit calculations. Many building simulation programs, such as DOE 2.1A or BLAST, are quite complex and must be run by specialists on main frame computers. A simplified method of commercial building energy analysis has been developed that utilizes a database of previous DOE 2.1A simulations to predict the outcome of other simulations. We have applied this methodology to an office building in one climate region and have found that it predicts heating, cooling, and total energy use very accurately. The main advantage of this methodology is that less specialized skill is required and only a microcomputer is needed to perform the analyses. Therefore, energy analyses can be done cheaply and quickly.
EXTRUSION AND LUBRICATION FLOWS OF VISCOPLASTIC FLUIDS WITH WALL SLIP

Abstract The simplest model flow which approximates the extrusion (shallow screw channels) and lubrication flow is the steady, laminar flow occurring between two infinitely long parallel plates i.e., the generalized plane Couette flow. Here we develop an analytical model of the generalized plane Couette flow of viscoplastic fluids. The deformation and flow behavior of viscoplastic fluids can be realistically represented with the Herschel-Bulkley constitutive equation, which we have utilized as the basis for the development of our analytical model. Furthermore, as also demonstrated here, the deformation behavior of viscoplastic fluids is generally complicated by the presence of wall slip at solid walls, which occurs as a function of the wall shear stress. The wall slip versus the wall shear stress behavior of viscoplastic fluids can be experimentally characterized using viscomelric flows, including steady torsional and capillary flows. Thus determined Navier's wall slip coefficient can then be utilized in ...
NMDA and quisqualate modulation of visceral nociception in the rat.

The effects of N-methyl-D-aspartic acid (NMDA; 100 fmol-1 nmol) or quisqualic acid (QA; 10 pmol-10 nmol) on visceromotor and pressor responses to noxious colorectal distention (CRD; 40 mmHg, 20 s duration, interstimulus interval: 4 min) were studied in awake rats. Lesser doses of NMDA (100 fmol-1 pmol) administered intrathecally (i.t.) to the lumbar spinal cord produced a dose-dependent facilitation of visceromotor as well as pressor responses to CRD (maximum with 1 pmol NMDA at 1 min). The greatest dose tested (1 nmol) attenuated these responses (maximum at 1 min) and also produced a caudally-directed biting and scratching behavior accompanied by vocalizations. NMDA did not produce any of the above effects when administered i.t. to the thoracic spinal cord. I.t. pretreatment with the NMDA receptor antagonist, D-2-amino-5-phosphonovaleric acid (D-APV; 1 pmol), which produced no change in baseline activity or control responses, blocked all NMDA-produced effects in a reversible manner. QA produced dose-dependent inhibitory effects on visceromotor as well as pressor responses to noxious CRD when given i.t. to the lumbar spinal cord but not on administration to the thoracic spinal cord. Three nmol QA produced maximum inhibition at 2 min after administration and also produced caudally-directed biting and scratching. All of the QA-produced effects were reversibly blocked by i.t. pretreatment with the non-NMDA receptor antagonist, 6,7-dinitroquinoxaline-2,3-dione (DNQX; 3 nmol), which produced no change in baseline activity or control responses. We also examined the effects of NMDA and QA on responses to graded intensities of CRD. One pmol NMDA selectively facilitated visceromotor responses to CRD at distention pressures of 40 and 80 mmHg but not at 20 mmHg. In contrast, 3 nmol QA inhibited visceromotor responses to CRD at all intensities tested. In summary, these data suggest that activation of NMDA and non-NMDA receptors in the spinal cord differentially modulates visceral nociceptive input. Spinal segmental NMDA receptor activation produces selective facilitation of visceral nociceptive processing at noxious intensities of stimulation and may thereby contribute to central mechanisms underlying visceral hyperalgesia.
High-resolution structure of the stable plasminogen activator inhibitor type-1 variant 14-1B in its proteinase-cleaved form: A new tool for detailed interaction studies and modeling

Wild-type plasminogen activator inhibitor type-1 (PAI-1) rapidly converts to the inactive latent state under conditions of physiological pH and temperature. For in vivo studies of active PAI-1 in cell culture and in vivo model systems, the 14-1B PAI-1 mutant (N150H-K154T-Q319L-M354I), with its stabilized active conformation, has thus become the PAI-1 of choice. As a consequence of the increased stability, the only two forms likely to be encountered are the active or the cleaved form, the latter either free or complexed with target proteinase. We hereby report the first structure of the stable 14-1B PAI-1 variant in its reactive center cleaved form, to a resolution of 2.0 A. The >99% complete structure represents the highest resolved structure of free cleaved PAI-1. This high-resolution structure should be of great use for drug target development and for modeling protein–protein interactions such as those of PAI-1 with vitronectin.
Electromagnetic Effects of Aircraft Wake-Active Feuillet Interaction

A mechanism by which an aircraft wake can interact strongly with the electromagnetic radiation present in an active elevated anomalous refractivity region (active feuillet) is analyzed. The aircraft wake structure, assumed to consist of twin contrarotating vortices plus entrained irrotational gas, trailing behind the wings of typical large aircraft is shown to be capable of descending a distance of approximately 3 wing span distances and attaining a length of the order of 10 km, prior to instability-induced disruption. The parcel of air such a descending coherent wake structure can convey into an active feuillet is demonstrated to alter significantly the local refractive index of the duct and induce substantial radiation spillage. The general characteristics of the electromagnetic radiation produced by this interaction process (i.e., scattering by diaphanous objects) is described.
Optimization of thermal processes using an Eulerian formulation and application in laser surface hardening

A systematic design approach has been developed for thermal processes combining the nite element method, design sensitivity analysis and optimization. Conductive heat transfer is solved in an Eulerian formulation, where the heat ux is xed in space and the material ows through a control volume. For constant velocity and heat ux distribution, the Eulerian formulation reduces to a steady-state problem, whereas the Lagrangian formulation remains transient. The reduction to a steady-state problem drastically improves the computational e ciency. Streamline Upwinding Petrov–Galerkin stabilization is employed to suppress the spurious oscillations. Design sensitivities of the temperature eld are computed using both the direct di erentiation and the adjoint methods. The systematic approach is applied in optimizing the laser surfacing process, where a moving laser beam heats the surface of a plate, and hardening is achieved by rapid cooling due to the heat transfer below the surface. The optimization objective is to maximize the rate of surface hardening. Constraints are introduced on the computed temperature and temperature rate elds to ensure that phase transformations are activated and that melting does not occur. Copyright ? 2000 John Wiley & Sons, Ltd.
Computational Investigation of Impact Energy Absorption Capability of Polyurea Coatings via Deformation-Induced Glass Transition

A number of experimental investigations reported in the open literature have indicated that the application of polyurea coatings can substantially improve blast and ballistic impact resistance/survivability of buildings, vehicles and laboratory test plates. While several potential mechanisms (e.g., shock-impedance mismatch, shock-wave dispersion, fracture-mode conversion and strain delocalization) have been proposed for the observed enhancement in the blast-wave/projectile-energy absorption, direct experimental or analytical evidence for the operation of these mechanisms has been lacking. Recently, it has been proposed that transition of polyurea between its rubbery-state and its glassy-state under high deformation-rate loading conditions is another possible mechanism for the improved ballistic impact resistance of polyurea-coated structures/test plates. In the present work, an attempt is made to provide computational support for this deformation-induced glass transition based energy-dissipation/absorption mechanism. Towards that end, a series of finite-element analyses of the projectile/coated-plate interactions are carried out using a transient non-linear dynamics finite-element approach. The results obtained are used to assess the extent of energy absorption and to identify the mode of failure of the test plate as a function of the imposed impact conditions. The results obtained show that the mechanical response of polyurea under impact conditions is a fairly sensitive function of the difference between the test temperature and the glass transition temperature. Specifically, when this difference is large, polyurea tends to display high-ductility behavior of a stereotypical elastomer in its rubbery-state. On the other hand, when the test temperature is closer to the glass transition temperature, polyurea tends to transform into its glassy-state during deformation and this process is associated with viscous type energy-dissipation. It is also argued that additional energy absorbing/dissipating mechanisms may contribute to the superior ballistic/blast protection capability of polyurea.
Stabilization of a model atom in superintense field ionization

Numerical simulation of multiphoton ionization of a one-dimensional model atom reveals new features in superintense laser fields. Graphs of above-threshold ionization (ATI) electron spectra and the corresponding time-dependent ionization probability curves show drastic changes from those of lower-intensity cases. A new type of ATI peak splitting as well as ionization rate suppression occur for high-frequency excitation with intensities up to approximately 25 a.u.
An efficient trust region method for unconstrained discrete-time optimal control problems

Discrete-time optimal control (DTOC) problems are large-scale optimization problems with a dynamic structure. In previous work this structure has been exploited to provide very fast and efficient local procedures. Two examples are the differential dynamic programming algorithm (DDP) and the stagewise Newton procedure both require only O (N) operations per iteration, where N is the number of timesteps. Both exhibit a quadratic convergence rate. However, most algorithms in this category do not have a satisfactory global convergence strategy. The most popular global strategy is shifting: this sometimes works poorly due to the lack of automatic adjustment to the shifting element. In this paper we propose a method that incorporates the trust region idea with the local stagewise Newton''s method. This method possesses advantages of both the trust region idea and the stagewise Newton''s method, i.e., our proposed method has strong global and local convergence properties yet remains economical. Preliminary numerical results are presented to illustrate the behavior of the proposed algorithm. We also collect in the Appendix some DTOC problems that have appeared in the literature.
Developing Asynchronous MBA Courses in the World Wide Web

This article describes the use of the Internet and the World Wide Web for the asynchronous delivery of MBA coursework. The planning and implementation processes are described, as are resources used to implement content creation and design of the delivery system. A Web committee was created to appraise the need for consultants, set priorities for course development, recommend content design, recommend hardware and software for delivery and student access, and study security for examinations.
Somali piracy negotiations: Resolving the paradoxes of extortionate transactions

This article examines the negotiation process within piracy hijackings that occur around Somalia. Access was provided to two Somali pirates who were interviewed about their roles: a financier and a navigator. This article views these hostage negotiations as extortionate transactions, which requires negotiators to confront five paradoxes in the course of forging an outcome. The interviews with the two pirates reveal how the pirates and the ship owners who do the negotiations manage these paradoxes in the settling on a ransom. The interviews reveal how the hijackings are organized and financed, how the negotiations are organized logistically, how the ransoms are paid, and what happens when negotiations reach sticking points. The article concludes with a discussion of how the negotiations are shaped by the paradoxes as each side crafts its position.
Perceptual-cognitive explorations of a toroidal set of free-form stimuli

Abstract A polar-coordinate analogue of Fourier synthesis generates organic-appearing “free forms” that can be continuously deformed along any desired number of difficult-to-verbalize dimensions. Since the dimensions are also circular, the forms correspond to points on the surface of a torus which, though conveniently finite, is free of bounding edges. Two experiments explore a particular two-dimensional set of 81 such forms. The first shows that perceived pair-wise similarities among the individual forms are well explained purely in terms of the distances among their corresponding points in the toroidal parameter space. The second, however, establishes that forms that tend to be grouped together as having the same cognitive interpretation define regions in parameter space that are variously shaped or even bimodal and, hence, that cannot be explained solely on the basis of the fixed set of pair-wise similarities. The stimuli appear to offer a novel combination of cognitive richness and low-dimensional parametric control.
A new one-parameter model for the distribution of chromosome breaks in human cells

Damage to genetic material can be brought about by chemicals, radioactivity, radiation, etc. This damage can be visualizedas chromosome aberrations such as chromosome and chromatid deletions, dicentrics, chromatid exchanges, and others. The study of chromosome aberration induction by chemical and physical agents has evolved over several decades and discrete distribution models have been developed to analyze the data generated in experimental studies. Most of these models have relied on the Poisson, binomial or negative binomial distributions (SAVAGE 1970, KOHLER et al. 1976, YANKOVENKO et al. 1976) to describe the frequency distribution of aberrations in a collection of cells. The intracellular distribution of lesions gives useful information about the mechanism of the interaction of the damaging agent with different cell components. Recently, JANARDAN and SCHAEFFER (1977), JANARDAN et al. (1979), and DuFRAIN et al. (1980) have proposed the use of the Langrangian Poisson Distribution (LPD) as a model of over-, under- or no dispersion relative to the Poisson. (The value of ~2, the parameter of the LPD, is a quantitative measure of the dispersion while its sign (+, -, O) indicates the direction.) However, certain asumptions which are used in the development of the LPD are restrictive of the more complex biologic phenomena being studied by cytogeneticists. Further, many workers have questioned the biologic significance of the improvement resulting from the use of two (or more) parameter models over the use of one parameter models, since additional parameters will result in mathematical improvement at the expense of a reduced number of degrees of freedom for the experimental data. In this paper we develop a new one parameter model, which we call the Poisson-Linear Exponential Distribution (PLED). This distribution is as good as many of the two parameter models at fitting experimental data. The assumptions of the model are developed from biologic observations. HYPOTHESES: I. There is a constant rate of aberration for a given cell. 2. The rate of aberrations varies from cell to cell.
Liquid Hydrogen as a Fuel for the Future

The use of liquid hydrogen as a long-term replacement for hydrocarbon fuel for land and air transportation seems technically feasible. It is an ideal fuel from the standpoint of a completely cyclic system, serving as a "working substance" in a closed chemical and thermodynamic cycle. The energy-per-unit-weight advantage (a factor of 3) over gasoline or any other hydrocarbon fuel makes liquid hydrogen particularly advantageous for air craft and long-range land transport. As a pollution-free fuel, it must be seriously considered as the logical replacement for hydrocarbons in the 21st century.
A novel double deprotection-peptide cyclisation procedure and its application to the synthesis of analogues of the cyclic tetrapeptide HC-toxin.

Abstract A hydroxide-mediated Fmoc/methyl ester double deprotection procedure followed by an improved bis(2-oxo-3-oxazolidinyl)phosphinic chloride (BOP-Cl) cyclisation reaction are reported. This novel methodology was applied to the synthesis of three new HC-toxin analogues.
Delineation of a clinical syndrome caused by mosaic trisomy 15

We report on a boy with mosaic trisomy 15. The clinical manifestations are compared with those of the few cases reported up to now. A clinical syndrome is delineated consisting of a characteristic shape of the nose and other minor craniofacial anomalies, as well as typical deformities of the hands and feet. Different degrees of mosaicism may explain the more or less severe manifestations in individual patients.
Transplantation as a tool to study progenitors within the vertebrate nervous system

In recent years, many studies have focused on the fate and potential of neural progenitors in vertebrates. While much progress has been made, many questions remain about the mechanisms which lead to neural diversity, in terms of both the regionalization of the nervous system and specification of cell fates within those regions. Studies aimed at addressing these questions have fallen into three main categories: in vivo lineage tracings, in vitro differentiation analyses, and in vivo cell transplantation studies. This body of work has pointed to the existence of both pluripotent and unipotent neural progenitors, and has suggested that both cell intrinsic and extrinsic cues play a role in the determination of neural cell fate. In addition, the existence of neural "stem cells" maintained into adulthood has been suggested. This review will focus on transplantation studies in mammals, and will emphasize how this method has been useful as a means of determining the changing potential of neural precursors and their environments within the developing nervous system.
Microscale electrophoresis of stress proteins induced by chemicals during the in vivo cell cycle

The incorporation of leucine and phosphate in proteins extracted with two different solvents from nuclei sorted physically from the G0+G1 phase of the rat submaxillary gland cell cycle was observed by two-dimensional microscale polyacrylamide gel electrophoresis. Sodium phenobarbital did not initiate additional isotope ([3H]leucine and [32P]phosphate) incorporation on its own. After dosing with DL-isoproterenol, several proteins incorporated leucine and phosphate during the G0+G1 phase. The inclusion of phenobarbital in the dosing regime enhanced labeling of several proteins already present in the G0+G1 phase. Treatment of animals with sodium arsenite prompted labeling of phosphate of two “stress” proteins in the non-dividing G0 phase of the submaxillary gland. Enhanced incorporation of proteins was exhibited after combined dosing of isoproterenol and sodium arsenite, but no new incorporated proteins were seen in the G0+G1 phase. Likewise, no new proteins were seen to incorporate in the G2+M phase, but there was some increased incorporation in a few already present proteins under these conditions. The similar mobilities of several stress proteins, which were determined by coelectrophoresis of stress marker proteins, suggested that several of these proteins, even though they were extracted with different solvents, were identical.
CHEMICAL DIFFUSION AND CRYSTALLINE NUCLEATION DURING OXIDATION OF FERROUS IRON-BEARING MAGNESIUM ALUMINOSILICATE GLASS

Abstract Rutherford backscattering spectroscopy (RBS) and transmission electron microscopy (TEM) have been used to evaluate the mechanism and kinetics of oxidation of a Fe2+-doped MgOAl2O3SiO2 glass (with nominal composition along the enstatite-cordierite-liquid divariant) which was heat treated in air under the time and temperature ranges 10–150 h and 700–800°C, respectively. The results clearly demonstrate that oxidation occurs by a cation diffusion process: specifically, the divalent cations diffuse from the interior of the glass to the free surface where they subsequently react with environmental oxygen to form a two-phase, MgO(Mg, Fe)3O4 crystalline layer which covers the (divalent cation-depleted) glass. Oxidation of some Fe2+ within the glass occurs via the inward flux of electron holes (a counterflux to the divalent cation diffusion required to maintain charge neutrality of the glass); this internal oxidation results in the fine-scale (∼ 1–5 nm), homogeneous nucleation of crystalline (Mg, Fe)3O4 within the divalent cation-depleted layer of the glass. Chemical diffusion of an oxygen species is thus demonstrated to be a slower, parallel kinetic process which is not required for oxidation to occur in this material. A first-order analysis of oxidation kinetics in the glass is presented.
Stimulus stringing by pigeons: Conditional strings

Pigeons were trained to produce one serial list in the presence of a green background cue and another serial list in the presence of a red background cue when the items for both serial lists were presented on each trial. This demonstrated a combination of serial learning and conditional discrimination learning not previously shown in pigeons. Specifically, when presented with four geometric forms, A B C D, in random locations of a five-key display, the pigeons learned to peck A B C when the background was green and A B D when the background was red. Accuracy on the conditional string ranged from 73% to 85%. Transfer tests using different locations of the stimuli on the keys showed positive transfer, thus ruling out learning of specific locations as the basis of the accurate performance. Above-chance performance was maintained when the conditional colors were presented only on the key that did not contain one of the serial stimuli. The results are interpreted in terms of a chaining model that postulates that the sequential selections were controlled by cues produced by both onset of the trial and prior selections within the trial.
Phase I trial of recombinant platelet factor 4 (rPF4) in patients with advanced colorectal carcinoma.

Background: Recombinant platelet factor 4 (rPF4) is a naturally occurring protein found in platelet alpha granules that can inhibit angiogenesis.
Fast semivariogram computation using FPGA architectures

The semivariogram is a statistical measure of the spatial distribution of data and is based on Markov Random Fields (MRFs). Semivariogram analysis is a computationally intensive algorithm that has typically seen applications in the geosciences and remote sensing areas. Recently, applications in the area of medical imaging have been investigated, resulting in the need for efficient real time implementation of the algorithm. The semivariogram is a plot of semivariances for different lag distances between pixels. A semi-variance, γ(h), is defined as the half of the expected squared differences of pixel values between any two data locations with a lag distance of h. Due to the need to examine each pair of pixels in the image or sub-image being processed, the base algorithm complexity for an image window with n pixels is 𝑂(𝑛2). Field Programmable Gate Arrays (FPGAs) are an attractive solution for such demanding applications due to their parallel processing capability. FPGAs also tend to operate at relatively modest clock rates measured in a few hundreds of megahertz, but they can perform tens of thousands of calculations per clock cycle while operating in the low range of power. This paper presents a technique for the fast computation of the semivariogram using two custom FPGA architectures. The design consists of several modules dedicated to the constituent computational tasks. A modular architecture approach is chosen to allow for replication of processing units. This allows for high throughput due to concurrent processing of pixel pairs. The current implementation is focused on isotropic semivariogram computations only. Anisotropic semivariogram implementation is anticipated to be an extension of the current architecture, ostensibly based on refinements to the current modules. The algorithm is benchmarked using VHDL on a Xilinx XUPV5-LX110T development Kit, which utilizes the Virtex5 FPGA. Medical image data from MRI scans are utilized for the experiments. Computational speedup is measured with respect to Matlab implementation on a personal computer with an Intel i7 multi-core processor. Preliminary simulation results indicate that a significant advantage in speed can be attained by the architectures, making the algorithm viable for implementation in medical devices
The microdetermination of ribonuclease.

Abstract A solution of ribonucleic acid when mixed at 37 ° with a solution containing serum albumin and gelatin gives a turbidity which may be measured at 400 mμ. The decrease in this turbidity with enzyme action permits the quantitative estimation of 1–50 mμg. of crystalline ribonuclease.
Effects of Positive and Negative Reinforcement in a Concurrent Operants Arrangement on Compliance and Problem Behavior

Functional analysis (Iwata, Dorsey, Slifer, Bauman, & Richman, 1982/1994) is a robust approach to identifying function-based interventions for problem behavior, including self-injury, aggression, and destruction. Such interventions, however, may be difficult for untrained caregivers to implement with fidelity in natural environments. Further research is needed to identify simple antecedent strategies for promoting appropriate behavior among children with significant problem behavior. The purpose of the current study was to utilize a concurrent schedules arrangement to identify conditions under which two children with autism spectrum disorder (ASD) and developmental delays who engaged in problem behaviors would choose to complete academic tasks to earn access to preferred items. In both cases, problem behaviors were shown to be sensitive to reinforcement in the forms of escape from task demands and access to preferred items. A concurrent operant arrangement in which the participants could choose to complete work tasks to earn access to preferred activities, or to take a break without demands or preferred items, was implemented. The schedule requirements in the demand component were systematically increased across opportunities, while the amount and type of reinforcement was kept constant. The results show, at the lowest levels of task demands, both participants allocated more opportunities to the work option. At higher levels, however, both participants allocated a majority of their choices to the break option. Despite the absence of preferred items in the break component, no instances of problem behavior were observed following selection of the break option. This indicates that this type of analysis could be used to identify conditions for compliance among individuals who engage in escape- or multiply-maintained problem behaviors, without the need to provoke or reinforce problem behavior. Limitations of the current study and recommendations for future research are discussed.
Bilateral radical neck dissection: Report of results in 55 patients

Between 1952 and 1982, 55 patients underwent bilateral radical neck dissections at the National Cancer Institute. Of these, 17 patients had simultaneous (one-stage) bilateral dissections and 38 had nonsimultaneous (two-stage) dissections. In 37 patients both internal jugular veins were removed, while one vein was preserved in 18 patients. The operative mortality was 11.8% (2/17 patients) for simultaneous bilateral neck dissections and 2.6% (1/38 patients) for nonsimultaneous staged dissections. The overall operative mortality was 5.4%. Of the 18 patients in whom one jugular vein was preserved, six patients (33%) had postoperative facial edema and swelling, while of the 37 patients in which neither jugular vein was saved, 20 patients (54%) developed significant postoperative facial edema. The overall 2-year recurrence rate was 50%. The overall survival rates were 55% at 3 years and 39% at 5 years.
Measurement of the Optical Properties of Leaves Under Diffuse Light

Measuring leaf light absorptance is central to many areas of plant biology including photosynthesis and energy balance. Absorptance is calculated from measured values of transmittance and reflectance, and most such measurements have used direct beam light. However, photosynthesis and other processes can differ under direct and diffuse light. Optical properties under diffuse light may be different, but there have been technical difficulties involved in measuring total reflectance of diffuse light. We developed instrumentation to measure this reflectance using a chopped measuring beam delivered alternately to sample and reference integrating spheres, and lock-in detection. We also built instrumentation for measuring transmittance of diffuse light. We developed standards to calibrate our instruments and correct for substitution error, a known systematic error with integrating sphere-based measurements. Helianthus annuus leaves measured under diffuse light reflected 5-10% more and transmitted a few percent less 400-700 nm light than under direct light. Overall absorptance was only a few percent higher under direct light, but leaves may utilize absorbed direct and diffuse light differently. For example, of the light entering the leaf, significantly more direct light than diffuse light is transmitted through the leaf, suggesting differences in localization of absorption within the leaf.
Meteoritic silicon carbide: pristine material from carbon stars

All five gases in interstellar silicon carbide grains have grossly nonsolar isotopic and elemental abundances that vary with grain size but are strikingly similar to calculated values for the helium-burning shell of low-mass carbon stars. Apparently these grains formed in carbon-star envelopes, and were impregnated with noble gas ions from a stellar wind. Meteoritic SiC provides a detailed record of nuclear and chemical processes in carbon stars.
Application of hidden Markov modeling to the characterization of transcription factor binding sites

The regulation of gene transcription in eukaryotes, though not well understood, is known to involve sequence specific recognition and binding of short DNA sequences (transcription elements) by regulatory proteins (transcription factors). The cis acting transcription elements can be found at a considerable distance upstream or downstream from the gene they control and are often orientation independent. The transcriptional state of a gene is thought to require the formation of a "transcription complex" where multiple elements and factors interact through DNA-protein and protein-protein binding events. As a step towards elucidating the process of transcription complex formation, the authors have developed a model of transcription factor-DNA binding based on Hidden Markov Models (HMM). The parameters of the HMM are probabilities from which an entropy measure can be calculated that characterizes the information requirements of the binding process. Alignment of the set of transcription elements against the HMM also yields information regarding the conserved positions recognized by the transcription factor. Finally, they examine the relationship between the entropy of the model and the accuracy of the model when used for pattern recognition: in general, pattern recognition efficient when the conservation of bases in the sites is fairly high. >
Finite groups with all subgroups not contained in the Frattini subgroup permutable

Let G be a finite group. A subgroup H of G is a permutable subgroup of G if HK = KH for all subgroups K of G. It will be shown that if all subgroups not contained in the Frattini subgroup are permutable in a group G, then all subgroups are permutable in G.
CATCH-UP GROWTH IS INTRINSIC TO THE EPIPHYSEAL GROWTH PLATE

Catch-up growth is believed to result from a central nervous system mechanism that compares actual growth to a set point and adjusts growth velocity accordingly. Alternatively, we hypothesized that catch-up growth is intrinsic to the growth plate. To test this hypothesis, we infused dexamethasone phosphate for 4 weeks directly into one proximal tibial growth plate of 5-week old rabbits and infused vehicle into the contralateral growth plate. Growth velocity at each tibial growth plate was determined radiographically. Dexamethasone decreased the growth velocity of the treated growth plate by 37 ± 8 % (mean ± SEM, p < 0.01) compared to the control, causing a growth deficit of 4.8 ± 1.2 mm (p<0.01). After the end of the infusion, the growth velocity of the dexamethasone-treated growth plate rebounded above that of the control and ultimately corrected 52 ± 10 % of the deficit (p<0.01). Because the catch-up growth occurred solely within the dexamethasone-treated growth plate, we conclude that catch-up growth is intrinsic to the epiphyseal growth plate and cannot be explained by a systemic mechanism.
Odontocete suction feeding: Experimental analysis of water flow and head shape

The role of cranial morphology in the generation of intraoral and oropharyngeal suction pressures in odontocetes was investigated by manipulating the jaw and hyolingual apparatus of submerged heads of three species presenting varied shapes. Hyoid and gular muscles were manually employed to depress and retract the tongue. Pressures were recorded at three locations in the oral cavity, as gape and site, speed, and force of pull were varied. A biomechanical model was also developed to evaluate pressure data. The species with the shortest, bluntest head and smallest mouth opening generated greater negative pressures. Suction generation diminished sharply as gape increased. Greatest negative pressures attained were around −45 mmHg (−6,000 Pa), a magnitude deemed suitable for capture of small live prey. Odontocetes utilizing this bidirectional flow system should profit by evolution of a rounder mouth opening through progressive shortening and widening of the rostrum and jaws, a trend evident in cranial measurements from fossil and recent odontocetes. Blunt heads correlate with anatomical, ecological, and behavioral traits associated with suction feeding. Small-gape suction (with minimally opened jaws) could be used by odontocetes of all head and oral shapes to draw prey sufficiently close to the mouth for suction ingestion or grasping via dentition. Principal limitations of the experimental and mathematical simulations include assumption of a stationary odontocete with static (open or closed) jaws and potential scaling issues with differently sized heads and gapes. J. Morphol., 2006. © 2006 Wiley-Liss, Inc.
The General Linear Model II

In the preceding chapter we derived the OLS estimator of the (coefficient) parameters of the GLM and proved that a number of properties can be ascribed to it. In so doing, we have not assumed any specific form for the distribution of the error process. It was, generally, more than sufficient in that context to assert that the error process was one of i.i.d. random variables with zero mean and finite variance. However, even though unbiasedness, consistency, and efficiency could be proved, the distributional properties of such estimators could not be established. Consequently, tests of significance could not be formulated. In subsequent discussion we shall introduce an explicit assumption regarding the distribution of the error process, and determine what additional implications this might entail for the OLS estimators. In particular, recall that the assumptions under which estimation was carried out were: (A.1) The explanatory variables are nonstochastic and linearly independent, i.e., if X = (x ti ) , t = 1 , 2 , … , T , i = 0 , 1 , 2 , … , n, is the matrix of observations on the explanatory variables then X is nonstochastic and rank (X) = n + 1; (A.2) The limit
Critical Line for H-Superfluidity in Strange Quark Matter?

Based upon the analogy to the electroweak phase diagram, I propose that in QCD there might be a critical line for a superfluid transition, in the plane of chemical potential and temperature. The order parameter has the quantum numbers of the H dibaryon, but the transition is driven by color superconductivity in strange quark matter. (c) 2000 The American Physical Society.
Characterization of the infection of equine fibroblasts by equine infectious anemia virus.

Equine dermal fibroblasts persistently infected with equine infectious anemia virus (EIAV) show no alterations in cell morphology or growth kinetics when compared to uninfected cells. The percentage of cells immunofluorescent positive for viral proteins fluctuated, depending upon the stage of the cell cycle, while production of extracellular virus was uniform throughout the cell cycle, increasing only as the cell number increased. This was shown in log versus stationary phase cultures as well as in cultures synchronized by serum starvation. The establishment of productive infection did not require host cell DNA synthesis. Normal levels of progeny virus were produced in cultures pretreated with mitomycin C and placed in serum-containing medium. Serum-starved cultures, however, did not support EIAV replication as well as other cultures, presumably because synthesis of provirus was inhibited.
The Q-cycle reviewed: how well does a monomeric mechanism of the bc1 complex account for the function of a dimeric complex?

Recent progress in understanding the Q-cycle mechanism of the bc(1) complex is reviewed. The data strongly support a mechanism in which the Q(o)-site operates through a reaction in which the first electron transfer from ubiquinol to the oxidized iron-sulfur protein is the rate-determining step for the overall process. The reaction involves a proton-coupled electron transfer down a hydrogen bond between the ubiquinol and a histidine ligand of the [2Fe-2S] cluster, in which the unfavorable protonic configuration contributes a substantial part of the activation barrier. The reaction is endergonic, and the products are an unstable ubisemiquinone at the Q(o)-site, and the reduced iron-sulfur protein, the extrinsic mobile domain of which is now free to dissociate and move away from the site to deliver an electron to cyt c(1) and liberate the H(+). When oxidation of the semiquinone is prevented, it participates in bypass reactions, including superoxide generation if O(2) is available. When the b-heme chain is available as an acceptor, the semiquinone is oxidized in a process in which the proton is passed to the glutamate of the conserved -PEWY- sequence, and the semiquinone anion passes its electron to heme b(L) to form the product ubiquinone. The rate is rapid compared to the limiting reaction, and would require movement of the semiquinone closer to heme b(L) to enhance the rate constant. The acceptor reactions at the Q(i)-site are still controversial, but likely involve a "two-electron gate" in which a stable semiquinone stores an electron. Possible mechanisms to explain the cyt b(150) phenomenon are discussed, and the information from pulsed-EPR studies about the structure of the intermediate state is reviewed. The mechanism discussed is applicable to a monomeric bc(1) complex. We discuss evidence in the literature that has been interpreted as shown that the dimeric structure participates in a more complicated mechanism involving electron transfer across the dimer interface. We show from myxothiazol titrations and mutational analysis of Tyr-199, which is at the interface between monomers, that no such inter-monomer electron transfer is detected at the level of the b(L) hemes. We show from analysis of strains with mutations at Asn-221 that there are coulombic interactions between the b-hemes in a monomer. The data can also be interpreted as showing similar coulombic interaction across the dimer interface, and we discuss mechanistic implications.
Potassium Cation Effects on Site Preferences in the Mixed Cation Zeolite Li,Na−Chabazite

The influence of potassium ions on the locations of Li+ and Na+ cations in dehydrated chabazites was studied by 7Li and 23Na magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy...
Resonant excitations of fast nuclei in crystals

Abstract Resonant excitations of nuclear levels are predicted when relativistic nuclei are directed along a crystal axis. The process is analogous to photo-excitation because the crystal's periodic Coulomb field is equivalent to a flux of photons. A resonance occurs when the periodicity of the lattice leads to a field at the nucleus whose frequency corresponds to a nuclear excitation frequency. The resonant nuclear excitation rate is not large. However, at very high projectile energies its observation is possible. In principle, such resonant excitation could yield new information on both nuclear photo-excitation rates and the electric fields in solids. Numerical results for a favorable example, electric dipole excitation of the 19F nucleus, are presented.
Simulating changes in forest recreation demand and associated economic impacts due to fire and fuels management activities

Abstract The objective of this study is to simulate the linkages from fire and fuels management activities to changes in forest recreation demand, and ultimately to regional economic impacts. Using available survey data collected in New Mexico (United States) during the summer of 2001, a pooled travel cost and contingent behavior model of forest recreation demand is developed. An endogenously stratified truncated Poisson model is used to estimate consumer surplus and predict changes in recreation visits under different fire and fuels management scenarios. Using the econometric results on the predicted changes in recreation demand, regional Input–Output models, at both the state (New Mexico) and local (southwestern New Mexico) level, are constructed to simulate the varying regional economic impacts of three different fire and fuels management scenarios. For comparison, we also simulate the regional economic impacts, at both the state and local level, of forest closure scenarios during a significant part of the summer recreation season in New Mexico.
Automotive airbag technology: past, present and future

Automotive airbag technology was studied from the development of the first airbag to the present driver and passenger side airbag systems as well as the development of the technology that will bring the current automotive airbag system into the century. Today's airbag system is a passive supplemental restraint that is used to cushion the driver or passenger during frontal impacts. Tomorrow's airbag system will be a "smart" adaptive restraint system that will tailor the airbag to the restraint needs of the occupants as well as performing occupant out-of-position sensing and child seat sensing to disable the airbag when a child seat is present.
Academic Excellence in the Urban Environment: Overcoming the Odds.

Poverty and a troubled environment have been overcome by many high achievers. Confidence and the will to succeed can enable students to succeed despite powerful odds against them.
Observations on congenital heart disease in a mortality study of children with cleft lip and palate.

Abstract An analysis of data based upon 1840 deaths of children born with facial clefts showed a strong association of congenital heart disease with cleft lip and cleft palate. Nineteen per cent of all deaths in children born with facial clefts were due to congenital heart disease. A more illuminating association of heart disease and clefts was discovered by including all heart defects mentioned on birth and death certificates of infants born with cleft lip or palate no matter what the underlying cause of death. From this analysis it was found that heart malformations had been recorded on birth or death certificates of 27 per cent of the deceased children. Total death rates for children born with facial clefts ascended progressively from isolated cleft lip through combined cleft lip and palate, to isolated cleft palate and Pierre Robin syndrome. The association of heart defects followed the same general pattern. There was a higher total death rate for females than males for clefts involving the lip, and higher rates for males with isolated cleft palate and Pierre Robin syndrome. Females with all types of clefts except Pierre Robin syndrome had higher rates of deaths with associated congenital heart disease than males.