cssi/SciSciGPT-SciSciNet huggingface dataset:
In vitro effects of hormonal stimuli upon tyrosinase and peroxidase activities in murine melanomas

Abstract ACTH and corticosterone altered tyrosinase activity in the B-16, S-91 and Harding-Passey melanomas but did not evoke any changes in peroxidase activity. Tyrosinase activity, but not peroxidase activity, was correlated with the degree of melanin pigmentation present in the melanomas. Thus, tyrosinase is the enzyme of physiological importance in the regulation of melanin pigmentation.
An Illustration of the Bias of OLS for Yt = λY t-1 + U t

(2000). An Illustration of the Bias of OLS for Yt = λY t-1 + U t. The Journal of Economic Education: Vol. 31, No. 1, pp. 76-80.
Modeling coupled migration and settling of particulates in curing filled epoxies

Epoxy resins filled to a high solids loading (40–60% by volume) with noncolloidal particles are used to mitigate stress and vibration in electronic components. We perform continuum-level finite element method (Schunk et al., A Full-Newton Finite Element Program for Free and Moving Boundary Problems with Coupled Fluid/Solid Momentum, Energy, Mass, and Chemical Species Transport: User's Guide, Sandia National Laboratories) simulations of filler particle redistribution during the nonisothermal cure of the epoxy under both quiescent and bulk flow conditions. An extent of reaction is used to track the degree of cure. To determine the particle migration, we couple a diffusive flux suspension model (Zhang and Acrivos, Int J Multiphase Flow 1994, 20, 579.) with the curing model. The heat transfer, including the exothermic polymerization reaction, is also modeled. The result is a generalized Newtonian model that has viscosity as a function of temperature, cure and particle volume fraction. With x-ray computed tomography, we examine settling of the particulate phase in both flowing and quiescent curing systems and compare the experimental results to the model predictions. The model is also validated with temperature measurements. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
CSCL as a catalyst for changing teacher practice

This paper presents results of a study of middle school teachers using a prototype Macintosh version of CSILE to help create a knowledge-building community. The study, involving middle schools in two school districts in the Southwest United States, provided teachers with training and technical support in the use of the CSILE over a period of one semester.In-depth interviews were conducted with the teacher participants a year after the termination of the project to understand their experiences and to learn their stories of the impact of the Knowledge-Building Community Project on their teaching practices. Five major themes emerged from the analysis of the interview transcription data. This paper presents a summary of the teacher reflections and stories related to the emergent theme of how the knowledge-building community changed their teaching practices, roles, the structure of their classroom discourse, and their views of curriculum. The results of the study suggest that CSILE, accompanied by appropriate support, can serve as a catalyst in changing teacher practices from didactic teaching to more constructivist approaches to learning. The paper presents teacher reflections on changes in their roles, views of curriculum and classroom discourse as a result of the knowledge-building community project.
Laser bleaching of trapped electron optical bands in γ-irradiated alkaline ice

Abstract The maximum of the optical absorption band of trapped electrons in glassy alkaline ice (10 mol/dm −3 NaOH) at 77 K shifts to higher energy when the low-energy side of the band is optically bleached. This suggests that there is a distribution of ground-state energies for the trapped electrons and, consequently, a distribution of vacancy sizes in which the electrons are trapped. The fine structure of the broad absorption band has been probed by comparing laser bleaching at 633 nm with broad-band monochromator bleaching at 633 nm. Although the laser linewidth is 750 times smaller than that of the monochromator light, the trapped-electron band shifts were equivalent, and it was not possible to bleach a narrow portion out of the broad band corresponding to a single narrow component or resolved single-energy trap depth. It appears that the width of the component optical band corresponding to a particular ground-state energy is broad rather than narrow. Laser bleaching in the low-energy tail of trapped electrons in KCl crystals caused uniform and symmetric bleaching consistent with a single trap depth.
Molecular dynamics calculation of critical point of nickel

The critical point of nickel and the phase diagram near the critical point are numerically evaluated using molecular dynamics (MD) computations. Thermodynamic states on the phase diagram are calculated for a homogeneous material at equilibrium states. Isothermal lines on p–v diagrams are constructed at temperatures below and above the critical temperature, and the liquid-gas coexistence lines and regimes are obtained. The critical point of nickel is obtained as T c = 9460± 20 K, ρ c = 2560± 100 kg· m−3, and p c = 1.08± 0.01 GPa. The method used in this work can be used to estimate thermodynamic properties of other materials at high temperature/pressure.
The use of an extra-focal electron source to model collimator-scattered electrons using the pencil-beam redefinition algorithm.

Currently, the pencil-beam redefinition algorithm (PBRA) utilizes a single electron source to model clinical electron beams. In the single-source model, the electrons appear to originate from a virtual source located near the scattering foils. Although this approach may be acceptable for most treatment machines, previous studies have shown dose differences as high as 8% relative to the given dose for small fields for some machines such as the Varian Clinac 1800. In such machines collimation-scattered electrons originating from the photon jaws and the applicator give rise to extra-focal electron sources. In this study, we examined the impact of modeling an additional electron source to better account for the collimator-scattered electrons. The desired dose calculation accuracy in water throughout the dose distribution is 3% or better relative to the given dose. We present here a methodology for determining the electron-source parameters for the dual-source model using a minimal set of data, that is, two central-axis depth-dose curves and two off-axis profiles. A Varian Clinac 1800 accelerator was modeled for beam energies of 20 and 9 MeV and applicator sizes of 15 x 15 and 6 x 6 cm2. The improvement in the accuracy of PBRA-calculated dose, evaluated using measured two-dimensional dose distributions in water, was characterized using the figure of merit, FA3%, which represents the fractional area containing dose differences greater than 3%. For the 15 x 15 cm2 field the evaluation was restricted to the penumbral region, and for the 6 x 6 cm2 field the central region of the beam was included as it was impacted by the penumbra. The greatest improvement in dose accuracy was for the 6 x 6 cm2 applicator. At 9 MeV, FA3% decreased from 15% to 0% at 100 cm SSD and from 34% to 4% at 110 cm SSD. At 20 MeV, FA3% decreased from 17% to 2% at 100 cm SSD and from 41% to 10% at 110 cm SSD. In the penumbra of the 15 x 15 cm2 applicator, the improvement was less, but still significant. At 9 MeV, FA3% changed from 11% to 1% at 100 cm SSD and from 10% to 12% at 110 cm SSD. At 20 MeV, FA3% decreased from 12% to 8% at 100 cm SSD and from 14% to 5% at 110 cm SSD. Results demonstrate that use of a dual-source beam model can provide significantly improved accuracy in the PBRA-calculated dose distribution that was not achievable with a single-source beam model when modeling the Varian Clinac 1800 electron beams. Time of PBRA dose calculation was approximately doubled; however, dual-source beam modeling of newer accelerators (e.g., the Varian Clinac 2100) may not be necessary because of less impact of collimator-scattered electrons on dosimetry.
Excited-State Energy-Transfer Dynamics of Self-Assembled Imine-Linked Porphyrin Dyads

Toward the development of new strategies for the synthesis of multiporphyrin arrays, we have prepared and characterized (electrochemistry and static/time-resolved optical spectroscopy) a series of dyads composed of a zinc porphyrin and a free base porphyrin joined via imine-based linkers. One dyad contains two zinc porphyrins. Imine formation occurs under gentle conditions without alteration of the porphyrin metalation state. Five imine linkers were investigated by combination of formyl, benzaldehyde, and salicylaldehyde groups with aniline and benzoic hydrazide groups. The imine-linked dyads are quite stable to routine handling. The excited-state energy-transfer rate from zinc to free base porphyrin ranges from (70 ps)(-)(1) to (13 ps)(-)(1) in toluene at room temperature depending on the linker employed. The energy-transfer yield is generally very high (>97%), with low yields of deleterious hole/electron transfer. Collectively, this work provides the foundation for the design of multiporphyrin arrays that self-assemble via stable imine linkages, have predictable electronic properties, and have comparable or even enhanced energy-transfer characteristics relative to those of other types of covalently linked systems.
Quantitative PCR Analysis of Mitochondrial DNA Content in Patients with Mitochondrial Disease

Molecular diagnosis of mitochondrial DNA disorder is usually focused on point mutations and large deletions. In the absence of detectable mtDNA mutations, abnormal amounts of mtDNA, either depletion or elevation, can be indicative of mitochondrial dysfunction. The amount of mitochondrial DNA (mtDNA), however, varies among individuals of different ages and among different tissues within the same individual. To establish a range of mtDNA levels, we analyzed 300 muscle and 200 blood specimens from patients suspected of having a mitochondrial disorder by real-tune quan-titative polymerase chain reaction (PCR) method. Copy numbers were calcu-lated from the standard curve and threshold cycle number using TaqMan probes; 6FAM 5′TTACCGGGCTCTGCCATCT3′-TAMRA and VIC-5′AGCAATAACAGGTCTGTGATG3′-TAMRA for mtDNA and 18S rRNA gene (nDNA), respectively. The copy number ratio of mtDNA to nDNA was used as a measure of mtDNA content in each specimen. The mtDNA content in muscle increases steadily from birth to about 5 years of age; thereafter, it stays about the same. On the contrary, the mtDNA content in blood decreases with age. The amount of mtDNA in skeletal muscle is about 5–20 times higher than that in blood. About 7% of patients had mtDNA levels in muscle below 20% of the mean of the age-matched group, and about 10% of patients had muscle mtDNA levels 2- to 16-fold higher than the mean of the age-matched group. Patients with abnormal levels of mtDNA, either depletion or proliferation, had significant clinical manifestations characteristic of mitochondrial disease in addition to abnormal respiratory enzymes and mitochondrial cytopathies. Cardiomyopathy, lactic acidosis, abnormal brain MRI findings, hypotonia, developmental delay, seizures, and failure to thrive are general clinical pictures of patients with mtDNA depletion. The average age of patients with mtDNA depletion is 4.1 years, compared to 23.6 years in patients with mtDNA proliferation. Mutations in nuclear genes involved in mtDNA synthesis and deoxynucleotide pools are probably the cause of mtDNA depletion. Our results demonstrate that real time quantitative PCR is a valuable tool for molecular screening of mitochondrial diseases.
THE RECOMMENDED DISSOCIATION CONSTANTS FOR CARBONIC ACID IN SEAWATER

A coherent representation of carbonate dissociation constants and measured inorganic carbon species is essential for a wide range of environmentally important issues such as oceanic uptake of anthropogenic CO2 and carbon cycle depictions in ocean circulation models. Previous studies have shown varying degrees of discordance between calculated and measured CO2-system parameters. It is unclear if this is due to errors in thermodynamic models or in measurements. In this work, we address this issue using a large field dataset (15,300 water samples) covering all ocean basins. Our field data, obtained using laboratory-calibrated measurement protocols, are most consistent with calculated parameters using the dissociation constants of Mehrbach et al. [1973] as refit by Dickson and Millero [1987]. Thus, these constants are recommended for use in the synthesis of the inorganic carbon data collected during the global CO2 survey during the 1990s and for characterization of the carbonate system in seawater.
Numerical determination of tristimulus values

I consider numerical methods for evaluating the tristimulus values of Pλ, an arbitrary spectral power distribution. Various classical quadrature rules are discussed, and numerically stable algorithms for their construction are presented. I introduce a new quadrature rule developed specifically for evaluating tristimulus values. The method involves the simultaneous generation of three quadrature rules sharing a common set of nodes that is optimal in a sense much like the optimality of the Gauss rules.
Distance distribution of nodes in star graphs

Abstract The purpose of the work is to provide a solution to the long-standing problem of computing the distance distribution among the nodes in a star graph, i.e., computing the exact number of nodes at a distance k from the identity node in a star graph where k varies from 0 to the diameter of the graph. A star graph is a Cayley graph like a hypercube; for a hypercube Q n , there are exactly n r nodes at a distance r from the identity node where r varies from 0 to n .
Process parameter selection for the consolidation of continuous fiber reinforced composites using finite element simulations

Abstract The foil/fiber/foil process is one of the most common techniques used to fabricate continuous fiber reinforced composites. In composites consisting of several alternate layers of foils and fibers, some of the fibers form a triangular array, while others are arranged in a rectangular pattern directly one above another. A finite element analysis using the commercial code ABAQUS has been employed in order to determine which of these fiber arrays densifies at a slower rate, and hence controls the densification process. The simulation results, based on composites comprised of Ti-6A1-4V foils and SCS-6 silicon carbide fibers, showed that the triangular array densifies much faster than the rectangular. Foils comprising the rectangular array must undergo much higher strain than those comprising the triangular array in order to produce a fully densified composite. A slowing of the densification in both types of fiber arrays was observed in the latter stages of pore closure after two neighboring foils had estabished contact with each other. This slowing may be attributed to the required increase in strain as well as the low stress levels existing in the vicinity of the pore. The simulation results were used to describe the process by a closed form relationship, and to generalize our results so they may be applied to any composite system, since it includes the processing parameters, as well as fiber spacing (or fiber volume fraction), foil thickness and fiber diameter. Densification maps showing the change of density with time for a range of processing temperatures and applied stresses were also constructed. These maps may be used to select the consolidation parameters that will minimize the reaction zone formation at the matrix-reinforcement interface, the residual stresses and other adverse effects.
Effects of early maternal docosahexaenoic acid intake on neuropsychological status and visual acuity at five years of age of breast-fed term infants

Objective We previously reported better psychomotor development at 30 months of age in infants whose mothers received a docosahexaenoic acid (DHA) (22:6n-3) supplement for the first 4 months of lactation. We now assess neuropsychological and visual function of the same children at 5 years of age. Study design Breastfeeding women were assigned to receive identical capsules containing either a high-DHA algal oil (∼200 mg/d of DHA) or a vegetable oil (containing no DHA) from delivery until 4 months postpartum. Primary outcome variables at 5 years of age were measures of gross and fine motor function, perceptual/visual-motor function, attention, executive function, verbal skills, and visual function of the recipient children at 5 years of age. Results There were no differences in visual function as assessed by the Bailey-Lovie acuity chart, transient visual evoked potential or sweep visual evoked potential testing between children whose mothers received DHA versus placebo. Children whose mothers received DHA versus placebo performed significantly better on the Sustained Attention Subscale of the Leiter International Performance Scale (46.5 ± 8.9 vs 41.9 ± 9.3, P Conclusions Five-year-old children whose mothers received modest DHA supplementation versus placebo for the first 4 months of breastfeeding performed better on a test of sustained attention. This, along with the previously reported better performance of the children of DHA-supplemented mothers on a test of psychomotor development at 30 months of age, suggests that DHA intake during early infancy confers long-term benefits on specific aspects of neurodevelopment.
Transition to a convective roll pattern as obtained from the stochastic center-manifold theory

We prove that the transition to a convective pattern in a Rayleigh-B\'enard cell with a step in the heat input can be obtained by restricting the system to the locally attractive and locally invariant center manifold in phase space. The problem of providing the adequate scaling factor for the random source in the order-parameter equation is solved and the theoretical findings reproduce satisfactorily the experimentally measured time dependence for the convective heat flow.
Reverse osmosis seawater desalination for power plant

Abstract The Miyazu Energy Research Center of the Kansai Electric Power Company in Kyoto prefecture has an electric power generating facility of 750,000 kW. As it is located in a small peninsula of a remote area, fresh water cannot easily be obtained and almost all of the fresh water required is provided by seawater desalination. The seawater desalination facility consists of two trains of the reverse osmosis (RO) equipment which produce 1600 m3/d fresh water. For the RO membrane, spiral-type polyether composite membranes (PEC-1000) made by Toray were adopted; there are 300 modules (60 vessels). The pretreatment, the dual-media filter and the single-medium filter are equipped in series and ferric chloride and sodium hypochlorite are injected for the removal of suspended particles in the raw seawater and the prevention of bacterial growth in the equipment. Before feeding the seawater to the membrane modules, the residual chlorine and dissolved oxygen are removed completely by vacuum declaration and addition of sodium bisulfite. Then the seawater is pressurized to 66 kg/cm3 and fed to the membrane modules. The seawater temperature changes from 9–37°C according to the season, and it causes the fluctuation of the fresh water production. In order to avoid scale formation on the membrane surface, the maximum recovery ratio was set at 45% (1800 m3/d). Therefore, the number of the membrane modules in operation is changed by the seawater temperature to keep the fresh water production between the minimum (1600 m3/d). The permeated water is decarbonated, and sodium hydroxide is added to adjust the pH between 6.5–7.5. The concentrated brine is discharged after oxidizing sodium bisulfite by aeration. The facility was constructed in 1988 and has been operating smoothly without serious problems since then. The outline of the operational results is reported in the paper.
Improving the Accuracy of Predicting Effectiveness Factors for mth Order and Langmuir Rate Equations in Spherical Coordinates

Char oxidation is often modeled using an mth order intrinsic reaction rate in conjunction with an effectiveness factor (η) to account for intraparticle diffusion of gas species. This approach invol...
Drosophila warts--tumor suppressor and member of the myotonic dystrophy protein kinase family

Tumor suppressor genes represent a broad class of genes that normally function in the negative regulation of cell proliferation. Loss-of-function mutations in these genes lead to unrestrained cell proliferation and tumor formation. A fundamental understanding of how tumor suppressor genes regulate cell proliferation and differentiation should reveal important aspects of signalling pathways and cell cycle control. A recent report describing the Drosophila tumor suppressor gene warts has implications in the study of the human myotonic dystrophy gene. These genes encode members of a cyclic AMP-dependent protein kinase subfamily that includes other plant and animal orthologues.
Step-through latencies in mice as a function of ECS-test interval ☆

Abstract Mice were given either foot shock followed by ECS, foot shock alone, ECS alone or neither following a step-through response in a one trial passive avoidance situation. Subjects were given retention trials at one of 14 retest intervals. Significant effects were found as a function of training condition and retest interval. At retest intervals of less than 480 min following ECS-manipulation, response latencies were largely controlled by the proactive effects of ECS, independent of the learning situation. Thus, unconfounded measures of retention following ECS were possible only at intervals where the proactive effects of ECS had attenuated. Retention of the passive avoidance response, as well as its attenuation by ECS, was shown at all retest intervals from 8 hr to 42 days.
The effect of nitric oxide on premixed flames of CH4, C2H6, C2H4, and C2H2

Abstract Nitric oxide was doped into premixed, stoichiometric, 10 torr flames of CH4/O2/N2, C2H6/O2/N2, C2H4/O2/N2, and C2H2/O2/N2. Spatial profiles of electronic ground state CH, OH, NO, CN, NCO, NH and metastable state 3C2 were obtained by laser-induced fluorescence. The peak temperatures of the flames were maintained at 1800 K by varying the N2 buffer gas mole fraction. Comparisons of the profiles among the different fuels illustrate differences in the hydrocarbon flame structure that lead to different NO reactivities in these flame systems. Concentrations of the nitrogen-containing intermediates are similar in the methane, ethane, and ethylene flames, but are considerably larger in the acetylene flame, indicating a much greater NO reactivity in this flame. The species profiles are modeled using three different kinetic mechanisms; all of these have significant shortcomings.
Distribution of PdBr2, RhBr3 and RuBr3 between the two immiscible liquid phases in the AlBr3-KBr system

Abstract The distribution behavior of palladium, rhodium and ruthenium bromides between the two immiscible liquid phases in the AlBr3-KBr system was determined at 110 °C. Distribution coefficients of 1.4, 1.7 and 3.2 were determined for PdBr2, RhBr3 and RuBr3 respectively. Visible and UV spectral studies of palladium dissolved in the two liquid phases indicated square planar PdBr42− to be the predominant palladium species in both phases. Similarly, octahedral RuBr63− was shown to be the distributing species for ruthenium.
Superfine IC geometries: Gas-plasma etching may supplant chemical etching in manufacturing high-performance integrated circuits

The advantages that dry etching offers over conventional chemical etching of integrated circuits are discussed. The underlying principle of dry etching is explained, and the various dry etching techniques in current use are described. The way in which voltage is created between plasma and wafer is explained, together with the mechanisms that produce directional etching. Attenuation is then given to the ability to operate over a wide pressure range and to monitoring based on light emission and DC bias. The dangers posed by overetching and energetic ions are discussed. Finally, the prospect of using expert systems in dry etching is assessed.
The john c. fremont 1842, 1843–’44 Report And map

Abstract John Charles Fremont’s 1842, 1843–’44 Report and map of his exploratory expeditions to the American West guided thousands of overland immigrants to the Oregon and California regions from the years 1845 to 1849. In 1849 Joseph Ware wrote the Emigrants’ Guide to California, which was largely drawn from Fremont’s Report, and was to guide the forty-niners through the California gold rush years. Fremont’s Report was more than a travelers’ guide—it was a U.S. government publication that achieved the expansionist objectives of a nation, and provided scientific and economic information concerning the potential of the trans-Mississippi West for pioneer settlement.
Enhanced absorption and electro-optic Pockels effect of electrostatically self-assembled CdSe quantum dots

The spectrum and electro-optic properties of CdSe quantum dots are studied. Spectrum wavelength shifts that are due to the quantum size effect and to the electro-optic Stark effect are investigated. It is found that CdSe quantum dot–polymer composites formed by an electrostatic self-assembly (ESA) technique exhibit high internal electric fields. Using the second-order perturbation theory of the 1s–1s energy shift (Stark effect), we estimate the internal field of the ESA film to be as high as 2.6 × 108 V/m. This value results in a much higher absorption coefficient and electro-optic coefficients for ESA films than for their bulk crystal counterparts or for spin-coated film samples. The relationships among unusual spectra, film structure, and high electro-optic response are analyzed. These results are useful both for understanding the physical mechanisms of semiconductor quantum dots and for developing high-performance photonic devices.
Density estimation under a two-sample semiparametric model

We consider estimating a density function under a two-sample semiparametric model in which the log ratio of two density functions is a quadratic function of data. This two-sample semiparametric model, arising naturally from case–control studies and logistic discriminant analysis, can be regarded as a biased sampling model. Under this model, the difference between the two samples is quantified. A kernel-based density estimator is constructed by smoothing the increments of the maximum semiparametric likelihood estimator of the underlying distribution function. The required computation for our method can be accomplished by using the standard statistical software packages for categorical data analysis. We establish some asymptotic results on the proposed kernel density estimator. In addition, we present some results on a simulation study and on the analysis of two data sets to demonstrate the utility of the proposed density estimator.
Sequence of the dengue-1 virus genome in the region encoding the three structural proteins and the major nonstructural protein NS1.

Abstract Sequence results are presented for a 3745-nucleotide region at the 5′ end of the dengue type-1 virus (DEN-1) genome. The strain characterized is a Western Pacific isolate from Nauru Island. The sequenced region contains the beginning of a continous open reading frame which specifies the capsid (C), membrane (M), and envelope (E) structural proteins and the nonstructural protein NS1. The sequences are compared with corresponding segments for seven other flaviviruses, including two of the three remaining dengue serotypes, DEN-2 and DEN-4. The results show the DEN-1 genome size and organization to be similar to those of other characterized flaviviruses and that major features of the individual proteins are conserved. It is of special interest that comparisons of the E glycoprotein sequences between the dengue serotypes (DEN-1, -2, -4) reveal only moderately greater sequence relatedness (63–68%) than occurs in comparisons of DEN-1 with five other flaviviruses (46–54%). For the other structural proteins, C and M, the relatedness values are 59–74% for comparisons between DEN-1 and the other dengue serotypes and 31–45% for comparisons between DEN-1 and the five other flaviviruses.
Sulfur yield of the 1600 eruption of Huaynaputina, Peru: Contributions from magmatic, fluid-phase, and hydrothermal sulfur

Abstract While major explosive eruptions of anhydrite-bearing silicic magma have been known to influence earth's climate through the release of sulfate aerosols, quantifying the atmospheric loading of these eruptions remains an elusive goal. The eruptions that have had the most impact on climate typically erupted oxidized and anhydrite-bearing magma. The > 9 km3 of dacite magma erupted during the VEI 6 eruption of Huaynaputina (Peru) in 1600 is oxidized (ƒO2 NNO + 1.4) but does not contain magmatic anhydrite. Yet it is thought to have a significant impact on climate. Herein we follow the approach that S contents in magmatic apatite grains can be used to provide an independent estimate of the magnitude and source of the atmospheric sulfur loading. Apatite SO3 concentrations of 0.09 to 0.17 wt.% yield an estimate of ~0.8 Mt of total erupted sulfur derived from degassing of the melt. This is considerably less than the stratospheric sulfur input of 16–55 Mt of S estimated from ice core data and requires that much of the stratospheric sulfur load from Huaynaputina was from other sources than the melt. While a fluid phase in equilibrium with the melt is a likely source, a significant contribution from combustion of sulfur from a fossil hydrothermal system excavated during eruption is evidenced by comminuted hydrothermal debris and lithics that make up to 2.5 to 10 wt.% of erupted material. We calculate that up to 22% of the total S budget of the eruption could reasonably be attributed to combusted hydrothermal sulfur. Thus, three sources of sulfur: the melt, a coexisting fluid phase, and external hydrothermal sulfur, appear to explain the atmospheric input from this eruption. Our work confirms that unraveling the S budget of large silicic eruptions is extremely complex and requires a multi-faceted approach based on a detailed understanding of the eruption.
The proton magnetic resonance spectra of the monohalobenzenes

Abstract Theoretical analyses of the PMR spectra of chloro-, bromo-, and iodobenzene, with the aid of deuterium decoupled spectra of the para deutero derivatives of the chloro- and bromo- compounds, have provided a complete set of spectral parameters for these compounds. Some surprisingly simple correlations have been observed between the shifts and the couplings, and between each of these and other molecular parameters. In general these results do not appear to be explicable in terms of the existing theories of these parameters.
A microeconomic approach to multi-objective spatial clustering

Application of clustering approaches in cross-disciplinary domains has necessitated the identification of new methods capable of simultaneous examination of multiple conflicting metrics during optimization. In this work, we propose a novel multi-objective clustering approach based on the concepts of microeconomic theory. In a multi-step, normal form game theoretic setup, each randomly initialized cluster is categorized as either a player or a resource in the game. The players in the game compete against each other for allocation of resources, and try to maximize their own utilities. The utility for a strategy of a player is a function of the clustering objectives. A Nash equilibrium based methodology is used to identify a solution that is socially fair. The algorithm is tested on real as well as artificially synthesized spatial data sets to evaluate the efficacy of the algorithm, and the quantitative measure of the quality of clusters in terms of fairness.
Dynamic model for the tissue concentration and oxygen saturation of hemoglobin in relation to blood volume, flow velocity, and oxygen consumption: Implications for functional neuroimaging and coherent hemodynamics spectroscopy (CHS)

This article presents a dynamic model that quantifies the temporal evolution of the concentration and oxygen saturation of hemoglobin in tissue, as determined by time-varying hemodynamic and metabolic parameters: blood volume, flow velocity, and oxygen consumption. This multi-compartment model determines separate contributions from arterioles, capillaries, and venules that comprise the tissue microvasculature, and treats them as a complete network, without making assumptions on the details of the architecture and morphology of the microvascular bed. A key parameter in the model is the effective blood transit time through the capillaries and its associated probability of oxygen release from hemoglobin to tissue, as described by a rate constant for oxygen diffusion. The solution of the model in the time domain predicts the signals measured by hemodynamic-based neuroimaging techniques such as functional near-infrared spectroscopy (fNIRS) and functional magnetic resonance imaging (fMRI) in response to brain activation. In the frequency domain, the model yields an analytical solution based on a phasor representation that provides a framework for quantitative spectroscopy of coherent hemodynamic oscillations. I term this novel technique coherent hemodynamics spectroscopy (CHS), and this article describes how it can be used for the assessment of cerebral autoregulation and the study of hemodynamic oscillations resulting from a variety of periodic physiological challenges, brain activation protocols, or physical maneuvers.
Cutting Edge: Naive T Cells Masquerading as Memory Cells

This study shows that naive CD8 T cells can acquire characteristics of memory T cells in the absence of stimulation with specific Ag simply by the process of homeostatic proliferation under lymphopenic conditions. This Ag-independent T cell differentiation pathway did not result in up-regulation of early activation markers (CD69, CD25, CD71), but expression of several memory markers (CD44, CD122, Ly6C) increased progressively with successive divisions. These markers were then stably expressed, and these cells also became more responsive functionally to specific Ag. Thus, all “memory” phenotype T cells in an individual may not be true Ag-experienced cells and may include naive cells masquerading as memory cells. These findings are specially relevant in cases of disease or treatment-induced lymphopenia such as in HIV-infected individuals or transplant recipients. In addition, this study may have implications for autoimmunity because homeostatic proliferation of naive T cells requires interaction with self peptide plus MHC molecules.
HOMFLY Polynomials of Some Generalized Hopf Links

The Hopf link, consisting of two unknots wrapped around each other, is the simplest possible nontrivial link with more than one component. We can generalize it to two bundles of "parallel" unknots wrapped around each other. In this paper, we show that when one of the two bundles has a fixed side, the HOMFLY polynomials of the links satisfy a system of recurrence equations. This leads to a procedure for computing explicit formulas for the HOMFLY polynomials.
Three-Dimensional Imaging of Toxoplasma gondii –Host Cell Interactions within the Parasitophorous Vacuole

The protozoan parasite Toxoplasma gondii is a representative of apicomplexan parasites that invades host cells through an unconventional motility mechanism. During host cell invasion it forms a specialized membrane-surrounded compartment that is called the parasitophorous vacuole. The interactions between the host cell and parasite membranes are complex and recent studies have revealed in more detail that both the host cell and the parasite membrane contribute to the formation of the parasitophorous vacuole. By using our a new specimen preparation technique that allows three-dimensional imaging of thick-sectioned internal cell structures with high-resolution, low-voltage field emission scanning electron microscopy, we were able to visualize continuous structural interactions of the host cell membrane with the parasite within the parasitophorous vacuole. Fibrous and tubular material extends from the host cell membrane and is connected to parasite membrane components. Shorter protrusions are also elaborated from the parasite. Several of these shorter fine protrusions connect to the fibrous material of the host cell membrane. The elaborate network may be used for modifications of the parasitophorous vacuole membrane that will allow utilization of nutrients from the host cell by the parasite while it is being protected from host cell attacks. The structural interactions between parasite and host cells undergo time-dependent changes, and a fission pore is the most prominent structure left connecting the parasite with the host cell. The fission pore is anchored in the host cell by thick structural components of unknown nature. The new information gained with this technique includes structural details of fibrous and tubular material that is continuous between the parasite and host cell and can be imaged in three dimensions. We present this technique as a tool to investigate more fully the complex structural interactions of the host cell and the parasite residing in the parasitophorous vacuole.
Automatic prediction of frustration

Predicting when a person might be frustrated can provide an intelligent system with important information about when to initiate interaction. For example, an automated Learning Companion or Intelligent Tutoring System might use this information to intervene, providing support to the learner who is likely to otherwise quit, while leaving engaged learners free to discover things without interruption. This paper presents the first automated method that assesses, using multiple channels of affect-related information, whether a learner is about to click on a button saying ''I'm frustrated.'' The new method was tested on data gathered from 24 participants using an automated Learning Companion. Their indication of frustration was automatically predicted from the collected data with 79% accuracy (chance=58%). The new assessment method is based on Gaussian process classification and Bayesian inference. Its performance suggests that non-verbal channels carrying affective cues can help provide important information to a system for formulating a more intelligent response.
No symptoms, no asthma: the acute episodic disease belief is associated with poor self-management among inner-city adults with persistent asthma.

Objective Asthma morbidity and mortality is highest among inner-city populations. Suboptimal beliefs about the chronicity of asthma may perpetuate poor asthma control among inner-city asthmatics. This study sought to characterize beliefs about the chronicity of disease and its correlates in a cohort of inner-city adults with persistent asthma. Design Prospective, longitudinal, observational cohort study. Patients One hundred ninety-eight adults hospitalized with asthma over a 12-month period at an inner-city teaching hospital. Measurements Sociodemographics, clinical history, disease beliefs, and self-management behaviors were collected by interview. Information on self-reported use of inhaled corticosteroids (ICS), peak flowmeters, and regular asthma visits was collected during hospitalization, and 1 month and 6 months after discharge. Results This cohort was predominantly low income and nonwhite, with high rates of prior intubation, oral steroid use, and emergency department visits and hospitalizations. Overall, 53% of patients believed they only had asthma when they were having symptoms, what we call the no symptoms, no asthma belief. Men patients, those ≥ 65 years old, and those with no usual place of care had greater odds of having the no symptoms, no asthma belief, and those receiving oral steroids all or most of the time or with symptoms most days had half the odds of having this belief (p Conclusion The single question, “Do you think you have asthma all of the time, or only when you are having symptoms?” can efficiently identify patients who do not think about or manage their asthma as a chronic disease.
The Contributions of Marketing To Strategic Management

Marketing helps strategic management at a philosophical, conceptual, and methodological level. Theory-building contributions are few. The marketing concept stresses that customers are the focal point of strategy. Marketing defines the environment in terms that customers think are important. Segmentation partitions customers into groups with common needs and the positioning concept frames strategic choke as decisions about which segments to serve and with whom to compete. An emerging theory of market evaluation helps dynamic analysis of customers, competitors, and strategic choices.
Bactericidal mode of titanium dioxide photocatalysis

Abstract When exposed to near-UV light, titanium dioxide (TiO 2 ) exhibits a strong bactericidal activity. However, the killing mechanism(s) underlying the TiO 2 photocatalytic reaction is not yet well understood. The aim of the present study is to investigate the cellular damage sites and their contribution to cell death. A sensitive approach using o -nitrophenol β- d– galactopyranosideside (ONPG) as the probe and Escherichia coli as model cells has been developed. This approach is used to illustrate damages to both the cell envelope and intracellular components caused by TiO 2 photocatalytic reaction. Treatment of E. coli with TiO 2 and near-UV light resulted in an immediate increase in permeability to small molecules such as ONPG, and the leakage of large molecules such as β- d– galactosidase after 20 min. Kinetic data showed that cell wall damage took place in less than 20 min, followed by a progressive damage of cytoplasmic membrane and intracellular components. The results from the ONPG assay correlated well with the loss of cell viability. Cell wall damage followed by cytoplasmic membrane damage leading to a direct intracellular attack has therefore been proposed as the sequence of events when microorganisms undergo TiO 2 photocatalytic attack. It has been found that smaller TiO 2 particles cause quicker intracellular damage. Evidence has been obtained that indicated that the TiO 2 photocatalytic reaction results in continued bactericidal activity after the UV illumination terminates.
Maintenance of Vigilance by Programmed Noise

Summary.-This research was designed to compare the relative effect of three environmental conditions on the performance of a simple vigilance task. The vigilance task consisted of a cathode ray tube display which was rnonicored by 30 Ss for 2 hr. Three environmental conditions were randomly introduced while S monitored the display. The conditions were a constant noise of 64.5 db, a variable noise having an average SPL of 64.5 db, and a quiet condition of 61 db. The results indicate that the probability of signal detection is higher for the variable noise condition than for the constant noise and quiet conditions. No difference in probability of detection was found between the latter two conditions. An explanation for the facilitating effect of sensory stimulation on vigilance is sought in terms of the alerting and general arousal effects attributed to the reticular activating system. Vigilance tasks are defined as those tasks that require the detection of changes in stimuli presented serially during long periods of time when S has little or no prior knowledge of the spatial pattern or temporal sequence of the stimuli. The decrement which occurs in the performance of vigilance tasks as a function of time reported in the classical studies of Mackworth (1944, 1945, 1950) has been verified by numerous investigators (Adams, 1956; Andrews, Ross, & Whittenburg, 1956; Bakan, 1955). S's performance on vigilance tasks may be influenced by task, organismic, and environmental variables. Attention in this research is centered on the role of the environmental variable of noise in maintaining vigilance. Ic is hyporhesized that under a condition of mild sensory deprivation which often accompanies simple vigilance tasks, S's performance will be facilitated by the introduction of an amplimde modulated noise. Recent research on the reticular activating system (RAS) provides theoretical support for the above hypothesis. According to Magoun (1952) ascending and descending tracts from the reticular system markedly influence central and peripheral neural activiry, resulting in both behavioral facilitation and central alertness that characterize the waking state. This may be explained by the fact thar all sensory stimuli reach the responsive reticular activating system and evoke a widely-spread alerting action over the cerebral cortex (French, 1958). Funcrions commonly accepted for the reticular system are the transition from sleep to waking and general alerting or
Does use of a virtual environment change reaching while standing in patients with traumatic brain injury

Although numerous virtual reality applications have been developed for sensorimotor retraining in neurologically impaired individuals, it is unclear whether the virtual environment (VE) changes motor performance, especially in patients with brain injuries. To address this question, the movement characteristics of forward arm reaches during standing were compared in physical and virtual environments, presented at different viewing angles. Fifteen patients with traumatic brain injuries (TBI) and 15 sex- and age-matched healthy individuals performed virtual reaches in a computer-generated courtyard with a flower-topped hedge. The hedge was projected on a flat screen and viewed in 3D format in 1 of 3 angles: 10° above horizon (resembling a real-world viewing angle), 50° above horizon, or 90° above horizon (directly overhead). Participants were instructed to reach with their dominant hand avatar and to touch the farthest flower possible without losing their balance or stepping. Virtual reaches were compared with reaches-to-point to a target in an equivalent physical environment. A set of kinematic parameters was used. Reaches by patients with TBI were characterized by shorter distances, lower peak velocities, and smaller postural displacements than reaches by control individuals. All participants reached ~9% farther in the VE presented at a 50° angle than they did in the physical environment. Arm displacement in the more natural 10° angle VE was reduced by the same 9-10% compared to physical reaches. Virtual reaches had smaller velocity peaks and took longer than physical reaches. The results suggest that visual perception in the VE differs from real-world perception and the performance of functional tasks (e.g., reaching while standing) can be changed in TBI patients, depending on the viewing angle. Accordingly, the viewing angle is a critical parameter that should be adjusted carefully to achieve maximal therapeutic effect during practice in the VE.