cssi/SciSciGPT-SciSciNet huggingface dataset:
EXPERIMENTAL TEST OF COULOMB'S LAW.

One of the classic "null experiments" tests the exactness of the electrostatic inverse-square law. The outer shell of a spherical capacitor is raised to a potential $V$ with respect to a distant ground, and the potential difference $\ensuremath{\Delta}V$ induced between the inner and outer shells is measured. If this induced potential difference is not zero, Coulomb's law is violated. For example, if we assume that the force between charges varies as ${r}^{\ensuremath{-}2+q}$, then $\frac{\ensuremath{\Delta}}{V}$ is approximately a tenth of $q$. In our experiment five concentric spheres are used. A potential difference of 40 kV at 2500 Hz is impressed between the outer two spheres. A lock-in detector with a sensitivity of about 0.2 nV measures the potential difference between the inner two spheres. We find $|q|\ensuremath{\le}1.3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}13}$. We also find comparable limits on the detected signal when the operating frequency is 250 Hz, and when the detector is synchronized with the charging current rather than with the charge itself.
Hedging International Stock Portfolios: Lessons From the 1987 Crash

tions. hedged and unhedged portfolios and found that the hedged portfolios clearly dominate. More recently, Eun and Resnick [1988], assessing the stock and bond markets of the U.S., Japan, the U.K., and West Germany, demonstrate that hedged portfolios exhibit less risk than their unhedged counterparts. An assessment of U.S., Japanese, British, and German markets by Perold and Schulman [1988] finds that the hedging of an investment in these markets can reduce risk substantially. The purpose of our article is to offer additional insights about hedged portfolios on an intertemporal basis, because the benefits derived from hedging are time-variant. Specifically, as the covariance structure between exchange rate and stock price movements can be influenced by the direction of the dollar, the effect of hedging on portfolio risk is influenced as well.
The Los Alamos three-stage Van de Graaff facility

Abstract The LASL three-stage accelerator facility is described in detail. The history and development of the large vertical Van de Graaff is covered up to the present configuration. The changes that have been made in the FN tandem as compared to the standard machine are described. Operating characteristics are given for both machines operating independently and in the series configuration. The facilities and equipment available for experiments are enumerated. Three-stage acceleration of tritons is discussed at length as an example of the facility's capabilities.
Guanidinoacetate methyltransferase activity in tissues and cultured cells

Guanidinoacetate methyltransferase, the enzyme catalyzing the last step in creatine biosynthesis, has previously been considered to be restricted to a few tissues, but it has been found to occur in the cultured cells H4Az C2 rat hepatoma, N4TG1 mouse neuroblastoma, and IMR-90 human fetal lung fibroblast, as well as in skeletal and cardiac muscle of the rat. Activity was highest in the hepatoma, but tissues and cultured cells of nonhepatic origin had 5-20% of the activity of rat liver. Dialyzed 100,000g supernatants prepared from cultured cells or skeletal muscle tissue yielded values for apparent Km in the range of 1.2-3.4 microM for S-adenosylmethionine and 0.050-0.096 mM for guanidinoacetate. Intact monolayers of the three types of cultured cells converted labeled guanidinoacetate in the culture medium to creatine, which was identified by chromatographic behavior and by reaction with creatine kinase. The amounts of guanidinoacetate converted to creatine by fibroblasts and neuroblastoma cells during an 18-h period of incubation suggested that synthesis was proceeding at rates approaching Vmax, even in medium containing the relatively low physiological concentrations of guanidinoacetate. Fibroblast and neuroblastoma cell monolayers also have the capacity to take up creatine provided in the culture medium. The amounts of creatine taken up by monolayers of those cells were measured under the same conditions that were used for measurement of creatine synthesis. Comparison of the amounts of creatine synthesized with the amounts taken up showed that synthesis can make a significant contribution to intracellular pools of creatine plus phosphocreatine in fibroblasts and neuroblastoma cells.
Effects of sulindac, sulindac metabolites, and aspirin on the activity of detoxification enzymes in HT-29 human colon adenocarcinoma cells.

Non-steriodal anti-inflammatory drugs (NSAIDs) have been found to reduce cancer rates in various segments of the gastrointestinal tract in both animals and humans. In this study we examined the effect of sulindac, sulindac sulfide, sulindac sulfone and aspirin on QR and GST activity. We found that sulindac itself increased QR activity as much as 2-fold over controls but had no effect on GST activity. Sulindac sulfone, a metabolite of sulindac which lacks the ability to inhibit prostaglandin (PG) synthesis, increased QR and GST to 1.5-fold over controls in both cases. Aspirin increased QR and GST to 1.5-fold and 3.5-fold over controls respectively. These data indicate that NSAIDs increase phase II enzyme detoxification enzyme activity. Consequently, this effect may contribute to the protective effect of NSAIDs against colon cancer and may be an anticarcinogenic effect of these drugs that is distinct from their ability to inhibit PG synthesis.
Teaching reading to children with neurofibromatosis type 1: a clinical trial with random assignment to different approaches

Aim Neurofibromatosis type 1 (NF1) is a genetic disorder with a cognitive profile that includes visual–spatial perception deficits and a high incidence of reading disability. There is a paucity of information about how this cognitively complex population responds to mainstream reading interventions. The clinical trial goals were to determine whether children and adolescents with NF1 and reading deficits (NF+RD) benefit from mainstream remedial reading programs and whether responsiveness varies with differences in program-related visual–spatial demands. Method Forty-nine participants (28 males, 21 females; aged 8–14y) with either NF+RD (n=17, 11 males, six females) or idiopathic reading deficit (IRD) (n=32, 17 males, 15 females) were randomly assigned to intensive remedial teaching using one of two multisensory reading programs: one with greater kinesthetic demands and the other with greater visual–spatial demands. Two control groups – wait-list IRD (n=14, 11 males, three females) and typically developing readers (n=26, 13 males, 13 females) – received no treatment. Repeated measures and multivariate ANOVA analyses compared each group's growth in reading achievement from pre- to post-testing. Results Treated groups showed significant growth whereas untreated groups did not. Comparing treated groups, the IRD group responded equally well to both interventions, whereas the NF+RD group showed a better response to the more kinesthetic approach. Interpretation Results suggest that multisensory remedial reading teaching that emphasizes kinesthetic demands more than visual–spatial demands is suitable for students with NF+RD.
Doppler Optical Coherence Tomography of Retinal Circulation

Noncontact retinal blood flow measurements are performed with a Fourier domain optical coherence tomography (OCT) system using a circumpapillary double circular scan (CDCS) that scans around the optic nerve head at 3.40 mm and 3.75 mm diameters. The double concentric circles are performed 6 times consecutively over 2 sec. The CDCS scan is saved with Doppler shift information from which flow can be calculated. The standard clinical protocol calls for 3 CDCS scans made with the OCT beam passing through the superonasal edge of the pupil and 3 CDCS scan through the inferonal pupil. This double-angle protocol ensures that acceptable Doppler angle is obtained on each retinal branch vessel in at least 1 scan. The CDCS scan data, a 3-dimensional volumetric OCT scan of the optic disc scan, and a color photograph of the optic disc are used together to obtain retinal blood flow measurement on an eye. We have developed a blood flow measurement software called "Doppler optical coherence tomography of retinal circulation" (DOCTORC). This semi-automated software is used to measure total retinal blood flow, vessel cross section area, and average blood velocity. The flow of each vessel is calculated from the Doppler shift in the vessel cross-sectional area and the Doppler angle between the vessel and the OCT beam. Total retinal blood flow measurement is summed from the veins around the optic disc. The results obtained at our Doppler OCT reading center showed good reproducibility between graders and methods ( 0.57 with visual field pattern deviation). Doppler OCT is a new method to perform rapid, noncontact, and repeatable measurement of total retinal blood flow using widely available Fourier-domain OCT instrumentation. This new technology may improve the practicality of making these measurements in clinical studies and routine clinical practice.
Experimental evaluation of frequency-domain optical image reconstruction in multitarget tissue-like phantoms

In this paper, we report our initial experience with multi- target imaging experiments. Our intent mimics that of our initial pass at single-target imaging; that is, to vary selected parameters over a modest range in order to demonstrate feasibility and quickly identify potential areas where performance degrades relative to single-target imaging studies. This work can then be supplemented with a more exhaustive and directed examination of certain imaging parameters in order to more fully identify the limitations of multi-target imaging in the laboratory. In order for this paper to be reasonably self-contained, we briefly and qualitatively review of our image reconstruction algorithm and our experimental procedures and parameters, the details of which have been discussed at length elsewhere.
Ethanol inhibition of antigen-induced histamine release from guinea pig lung: Correlation with intracellular levels of cyclic nucleotides

Abstract The effect of ethanol on histamine release from lungs of sensitized guinea pigs was studied in conjunction with measurements of tissue concentrations of cyclic AMP and cyclic GMP. Addition of antigen in vitro elicited a rapid increase in cyclic AMP and cyclic GMP and stimulated release of histamine. Ethanol (2%) inhibited antigen-induced release of histamine over 95% and completely inhibited the increase in both cyclic nucleotides. The activity of cyclic AMP-dependent protein kinase was only slightly affected by ethanol. Metiamide blocked the ovalbumin stimulated increase in cyclic AMP but not cyclic GMP. Pyrilamine did not prevent the rise in either cyclic nucleotide. This suggests that the antigen-induced rise in cyclic AMP is an indirect result of histamine released from the tissue. The inability of H1 and H2 receptor antagonists to affect antigen-induced elevation of cyclic GMP in sensitized lung fragments suggests that an elevation in cyclic GMP might be either a primary event in the mediator release sequence or secondary to the release of a mediator other than histamine. The ability of ethanol to inhibit mediator release might be due to its capacity to attenuate the antigen-induced elevation of cyclic GMP in sensitized lung.
DIMENSION SUBGROUPS AND p-TH POWERS IN p-GROUPS

We prove that if the nilpotence class of ap-group is strictly less thanp kthen every product ofp k-thpowers can be written as thep-th power of an element. Scoppola and Shalev have proven the same thing for groups of class strictly less thanp k−p k−1. They also provide an example which proves that ours is the best possible result. This is a generalization of the well known fact that in groups of class strictly less thanp every product ofp-powers is again ap-th power. Along the way we prove results of independent interest on dimension subgroups ofp-groups.
Catalytic combustion effects of m-ZrO2 doped with various metal nitrates

Considerable uncertainty exists over the potential benefit of zirconia thermal barrier coatings (TBCs) in diesel engines, as well as their possible effect on NO x and other emissions. In the present study, a simple furnace system was used to identify catalytic combustion effects in the ignition and combustion of propane/air mixtures over catalyst-doped m-ZrO 2 spheres. Three classes of catalysts were examined: zirconia-stabilizing oxides (CeO 2 , Y 2 O 3 , MgO), transition metal oxides (Co 3 O 4 , Cr 2 O 3 , Fe 2 O 3 ), and noble metals (Pt). Each class exhibited characteristic combustion effects, with the ignition temperature increasing, e.g., from approximately 200°C for Pt to 550°C for the stabilizing oxides. The results are discussed in relation to diesel engine combustion, including the controversial Woschni effect wherein heat-insulating TBCs are postulated to actually increase heat loss from the combustion chamber.
Species profiles in solid propellant flames using absorption and emission spectroscopy

Abstract A windowed strand burner with a propellant feed mechanism has been used to characterize the steady-state burning of two composite propellants, M-30 and HMX1, at moderate pressure. Both emission and absorption spectroscopy have yielded profile data on three important combustion species: OH, NH, and CN. Relative appearances of these three species are inferred from emission intensity profiles, and absolute concentration profiles are calculated from the absorption data. This is the first absolute determination of these combustion intermediates in a propellant flame. The concentration measurements for OH indicate that the propellant flame temperatures are about 200 and 100 K below adiabatic for M-30 and HMX1, respectively. A maximum value of 43 ppm NH is found for the M-30 propellant flame. Fluctuations in the flame front of HMX1 compromised the determination of maximum concentrations for NH and CN.
Digital Identification of A Continuous Time System and Some Related Problems

A scheme is presented in the paper for digital identification of a continuous time system. The identifier proposed operates on the sampled input outpt data, but generates an estimate of the unknown continuous time system directly. Convergence analysis of the identifier is given in the paper. Also dicussed in the paper are some related problems. In particular, convergence of the identifier requires the persistent excitation condition on some signals in the identfication loop and that condition is reduced to the controllablity and observability of the sampled system of the unknown continuous time system. A result is derived in the paper concerning the controllability and observability of sampling an unknown continuous time system.
The thermal structure of subduction zones constrained by seismic imaging: Implications for slab dehydration and wedge flow

Thermal models of subduction zones often base their slab–wedge geometry from seismicity at mantle depths and, consequently, cannot be used to evaluate the relationship between seismicity and structure. Here, high-resolution seismic observations from the recent Broadband Experiment Across the Alaska Range (BEAAR) constrain, in a rare instance, the subducting slab geometry and mantle wedge temperature independent of seismicity. Receiver functions reveal that the subducting crust descends less steeply than the Wadati-Benioff Zone. Attenuation tomography of the mantle wedge reveals a high Q and presumably cold region where the slab is less than 80 km deep. To understand these two observations, we generate thermal models that use the improved wedge geometry from receiver functions and that incorporate temperature- and strain-rate-dependent olivine rheology. These calculations show that seismicity within the subducting crust falls in a narrow belt of pressure–temperature conditions, illuminating an effective Clapeyron slope of 0.1 K/MPa at temperatures of 450–750 °C. These conditions typify the breakdown of high-pressure hydrous minerals such as lawsonite and suggest that a single set of dehydration reactions may trigger intermediate-depth seismicity. The models also require that the upper, cold nose of the mantle wedge be isolated from the main flow in the mantle wedge in order to sustain the cold temperatures inferred from the Q tomography. Possibly, sufficient mechanical decoupling occurs at the top of the downgoing slab along a localized shear zone to 80 km depth, considerably deeper than inferred from thrust zone seismicity.
Template synthesis of electronically conductive polymers—preparation of thin films☆

Abstract We have recently developed a method for synthesizing micro and nanoscopic fibers and tubules of electronically conductive polymers. This method entails synthesis of the polymer within the pores of a microporous host membrane. Conductivities in the narrowest of these “template-synthesized” tubules and fibers can be significantly higher than in conventional forms ( eg powders or thin films) of the analogous polymer. These previous conductivity data were based on a two-point measurement of the resistance of the host membrane after synthesis of the conductive polymer fibers within this membrane. In this paper we will show results of conductivity measurements on thin films composed of the template-synthesized tubules and fibers. A four-point conductivity measurement was used on these thin films. These four-point measurements corroborate the earlier two-point conductivity data and, again, show that the template-synthesized materials are significantly more conductive.
On the mechanism of THF catalyzed vinylic lithiation of allylamine derivatives: structural studies using 2-D and diffusion-ordered NMR spectroscopy.

N-Lithio-N-(trialkylsilyl)allylamines can be deprotonated in the presence of ethereal solvents exclusively at the cis-vinylic position to yield 3,N-dilithio-N-(trialkylsilyl)allylamines under mild conditions. Low temperature 1H and 7Li NMR (1H NOESY, TOCSY, 1H/7Li HSQC, and DO-NMR) studies on the solution structure of 3,N-dilithio-N-(tert-butyldimethylsilyl)allylamine identified three major aggregates in THF (monomer, dimer and tetramer), but the aggregate structures failed to explain the solvent dependence and regiochemical outcome of the reaction. Low temperature 1H NMR (NOESY, TOCSY, DO-NMR) studies on the solution structure of N-lithio-N-(tert-butyldimethylsilyl)allylamine in the presence of nBuLi identified amide/nBuLi mixed aggregates in both the ethereal solvent THF (1:1 dimer) and the hydrocarbon solvent toluene (1:3 tetramer). Addition of 2 equiv of THF to toluene solutions induces the formation of the same THF solvated 1:1 dimer as observed in neat THF. NMR evidence suggests that in THF the mixe...
Kv1 potassium channel C-terminus constant HRETE region: arginine substitution affects surface protein level and conductance level of subfamily members differentially.

We have shown previously that truncating all of the variable cytoplasmic C-terminus of Kv1.1 potassium channels to G421stop had only a small inhibitory effect on their cell surface conductance density levels and cell surface protein levels. Here we investigated the role of a highly conserved cytoplasmic C-terminal charged region of five amino acids (HRETE) of the S6 transmembrane domain in the protein and conductance expression of Kv1.1, Kv1.2, and Kv1.4 channels. For Kv1.1 we found that E420stop, T419stop, and E418stop showed cell surface conductance densities and cell surface protein levels similar to full length control, whereas R417stop and H416stop exhibited essentially no conductance but their surface protein levels were similar to full length control. A bulky non-negatively charged hydrophilic amino acid at position 417 appeared to be critical for wild type gating of Kv1.1 because R417K and R417Q rescued conductance levels whereas R417A or R417E did not. The R417A mutation in the full length Kv1.1 ...
Optimal foraging and intraspecific diet differences in the lizard Cnemidophorus sexlineatus

Previous studies have shown that adult and juvenile six-lined racerunners, Cnemidophorus sexlineatus, consume different sizes and taxa of arthropod prey. the purpose of this study was to determine if these differences could be explained in terms of energy cost and benefit parameters as related by the optimal diet model. Handling times and encounter rates with each of five categories of prey were determined by direct observation of lizard foraging behavior in the field. Energetic cost of search and energy content of prey were estimated from data in the literature. Mean values of all these parameters were used in the classic optimal diet model to determine which prey types yield the greatest rate of net energy gain for adult and juvenile racerunners. Grasshopper-like insects were the most valuable prey for adults, whereas plant and ground arthropods were the most valuable prey for juveniles. These findings correspond to the age-class specific diet differences.
Circadian oscillators, cell cycles, and singularities: light perturbations of the free-running rhythm of cell division in Euglena.

The free-running circadian rhythm of cell division in the algal flagellate,Euglena gracilis (Z) was perturbed by 3-h light signals of varying intensities imposed at different circadian times (CT). Light pulses within the range of 700 to 7,500 lux were found to yield the same ‘strong’ (Type 0) phase response curve (PRC) comprising both advance and delaye phase shifts as great as 15 h. Dark signals generated a PRC of reduced amplitude with very little, if any, phase advance being observed. Light perturbations of lower intensity, however, elicited quite different responses if applied at a quite specific circadian time: A 40- to 400-lux pulse given at approximately CT 0 (late subjective night) induced total arrhythmicity, and the culture reverted to asynchronous, exponential growth. Different degrees of arryhtmicity were induced by the same low-intensity perturbations (I*) given slightly before or after this sensitive phase point (T*), but if imposed at other circadian times, they generated normal type 0 phase resetting. The demonstration of the existence of this critical pulse (T*,I*) provides further evidence that the cell division cycle ofEuglena (and presumably other microorganisms) is regulated by a circadian oscillator and, in particular, by one having limit cycle dynamics.
Mixed data analysis: Advanced integration techniques

AbstractThe purpose of this paper is to provide a coherent and inclusive framework for conducting mixed analyses. First, we present a two-dimensional representation for classifying and organizing both qualitative and quantitative analyses. This representation involves reframing qualitative and quantitative analyses as either variable-oriented or case-oriented analyses, yielding a 2 (qualitative analysis phase vs. quantitative analysis phase) × 2 (variable-oriented analysis vs. case-oriented analysis) mixed analysis grid. We present a comprehensive list of specific qualitative (e.g. method of constant comparison) and quantitative (e.g. multiple regression) analyses that fit under each of the four cells. Next, we provide an even more comprehensive framework that incorporates a time dimension (i.e. process/experience-oriented analyses), yielding a 2 (qualitative analysis phase vs. quantitative analysis phase) × 2 (particularistic vs. universalistic; variable-oriented analysis) × 2 (intrinsic case vs. instrum...
An axis of good and awful in odor reception.

Patchy variation in odor-evoked electrical activity in the human olfactory epithelium is found to correlate with stimulus pleasantness. This finding depends on a new technique for recording directly from awake humans.
The Grammar of Taiwanese Traditional Vernacular Dwellings

A shape grammar, which can exemplify and visually explain the style of Taiwanese traditional vernacular dwellings, is presented in the form of rules of composition that are derived from considerations of traditional processes of design and construction, and from cultural influences.
Vortex Shedding and Periodic Combustion Processes in a Rijke Type Pulse Combustor

Abstract This paper presents the initial results of an investigation of the mechanism that controls the operation of a Rijke type pulse combustor with tangential reactant injection. The study is focused on the role played by reacting vortices, generated in the initial section of the shear layers of the injected reactant flow, upon the driving of the pulsations. Detailed spatial distributions of the reaction rates were obtained by an intensified imaging system. They reveal that reacting, vortex-like, structures are formed near the region where the reactants enter the injection duel when the combustor pressure is near its minimum. Subsequently, these reacting structures grow in size and merge with each other. The merging process is accompanied by a dramatic increase in the reaction intensity that occurs when the combustor pressure reaches its maximum. This satisfies Rayleigh's criterion for driving pulsations by a heat addition process. In contrast, images obtained when the combustor is operated in a steady...
A compact gas Cherenkov detector with novel optics

Abstract We discuss the design and performance of a threshold Cherenkov counter for identification of charged hadrons. The radiator is pressurized gas, which is contained in thin-walled cylindrical modules. A mirror system of novel design transports Cherenkov photons to photomultiplier tubes. This system is compact, contains relatively little material, and has a large fraction of active volume. A prototype of a module designed for the proposed CLEO III detector has been studied using cosmic rays. Results from these studies show good agreement with a detailed Monte Carlo simulation of the module and indicate that it should achieve separation of pions and kaons at the 2.5σ–3.0σ level in the momentum range 0.8−2.8 GeV c . We predict performance for specific physics analyses using a GEANT-based simulation package.
Two‐dimensional efficient metamaterial‐inspired electrically‐small antenna

Inexpensive, efficient, and electrically-small antenna designs are presented, which are based on a two-dimensional (2D) metamaterial-inspired structure driven by an electrically-small rectangular semiloop antenna that is coaxially-fed through a finite PEC ground plane. Measured reflection coefficients showed a very good agreement with the simulated data, where the measured resonant frequency is only 0.5% different from the numerically predicted value. The proposed 2D antenna systems are linearly scalable with frequency, and predicted radiation characteristics of the antenna systems at 300, 430, and 1580 MHz are reported. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1669–1673, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22542
A new sparsity-enabled signal separation method based on signal resonance

This paper proposes the separation of signal components based on resonance. The method relies on several recent developments in sparse signal processing: morphological component analysis (MCA), the rational-dilation wavelet transform (RADWT), and fast algorithms for l 1 -norm regularized linear inverse problems (for example, SALSA). The RADWT allows one to extract signal components according to resonance characteristics because the RADWT allows the Q-factor (frequency resolution) of the wavelet transform to be varied. The sought decomposition can not be accomplished by frequency-based filtering. An example illustrates the method.
Effect of cytoskeletal geometry on intracellular diffusion.

A method is presented for determining the retardation of diffusion of particles inside cells owing to cytoskeletal barriers. The cytoskeletal meshwork is treated as a repeating periodic two-dimensional or three-dimensional lattice composed of elements of given size, shape, and spacing. We derive an analytic expression for the diffusion coefficient relative to that of the cytosol. This expression is evaluated by solving numerically an appropriate boundary-value problem for the Laplace equation. For the two-dimensional case, e.g., diffusion in a membrane, the results are quantitatively similar to those obtained by Saxton (1987. Biophys. J. 52:989–997) using Monte Carlo methods. The three-dimensional results are quantitatively similar to experimental results reported by Luby-Phelps et al. (1987. Proc. Natl. Acad. Sci. USA. 84:4910–4913) for the diffusion of dextran and Ficoll particles in Swiss 3T3 cells. By accounting for geometrical factors, these results allow one to assess the relative contributions of geometrical hindrance and of binding to the cytoskeletal lattice from measurements of intracellular diffusion coefficients of proteins.
Electron Transport in PEFCs

A three-dimensional, single-phase, isothermal numerical model of polymer electrolyte fuel cell ~PEFC! was employed to investigate effects of electron transport through the gas diffusion layer ~GDL! for the first time. An electron transport equation was additionally solved in the catalyst and gas diffusion layers, as well as in the current collector. It was found that the lateral electronic resistance of GDL, which is affected by the electronic conductivity, GDL thickness, and gas channel width, played a critical role in determining the current distribution and cell performance. Under fully-humidified gas feed in the anode and cathode, both oxygen and lateral electron transport in GDL dictated the current distribution. The lateral electronic resistance dominated the current distribution at high cell voltages, while the oxygen concentration played a more decisive role at low cell voltages. With reduced GDL thickness, the effect of the lateral electronic resistance on the current distribution and cell performance became even stronger, because the cross-sectional area of GDL for lateral electron transport was smaller. Inclusion of GDL electron transport enabled the thickness of GDL and widths of the gas channel and current collecting land to be optimized for better current distribution and cell performance. In addition, the present model enables: ~i! direct incorporation of contact resistances emerging from GDL/catalyzed membrane or GDL/land interface, ~ii! implementation of the total current as a more useful boundary condition than the constant cell voltage, and ~iii! stack modeling with cells connected in series and hence having the identical total current.
Internships That Make A Difference: Two Campuses Continuous Internship Improvement Experience

Internships have been used by many academic programs to augment the student’s educational experience. We discuss two internship programs that have been continuously refined in recent years to provide the students with a structured learning experience. We present a model for enriching student experiences by integrating internship experiences with academic experiences.
Design and analysis of antenna systems properly integrated into a spacecraft structure

For antennas located in a complex structural environment, such as a spacecraft, the structures can significantly impact the desired antenna pattern performance. The scattered fields from these structures due to the illumination of the antenna can create interference to the patterns of the antenna. Consequently, it is very important for antenna design engineers to be aware of the surrounding structures of the antenna and take the possible scattering effects into consideration, including the antenna and the structures. The proper use of computer codes can greatly help the engineers to achieve a much better overall design for the spacecraft in a cost effective way. The scattered field analysis approach, which uses the uniform geometrical theory of diffraction (GUTD), presented in this paper has been used to study the impact of the structure scattering in several commercial satellite systems as well as the international space station and helped the design engineers to find a better way of integrating the antennas into the spacecraft structure.
Non-dissipative rail drivers for adiabatic circuits

Energy dissipation of CMOS circuits is becoming a major concern in the design of digital systems. Earlier, we presented a new form of CMOS charge recovery logic (SCRL), with an energy dissipation per operation that falls linearly with operating frequency, as opposed to the constant energy required for conventional CMOS circuits. These SCRL circuits, along with most adiabatic circuit techniques proposed to date, require a set of gradually swinging power supply rails that in effect force all charge transfers within the system to occur quasistatically. Proposals to date for generating these swinging rails have relied on a power MOSFET to gate the oscillation of an inductor, forming an RLC circuit. Even under ideal conditions, dissipation in this MOSFET degraded the overall energy savings of SCRL circuits from 1/T dependence to 1//spl radic/T. SCRL and other adiabatic circuits thus exhibited inferior overall energy saving performance when compared with supply voltage scaling of conventional CMOS circuits. In this paper, we present a technique for generating the required rail waveforms without the series power MOSFET to gate the inductor. This new rail driver circuit relies on adding multiple harmonics of the base frequency to generate a rail waveform of any desired shape. Our Harmonic Rail Driver (HRD) can be built using only passive reactive components or by using correctly trimmed transmission line segments. It is non-dissipative to within the achievable Q's of these components. Using HRDs to power and control SCRL circuits, we restore the overall dissipation of SCRL circuits to its attractive 1/T dependence.
Cascadia: A System for Specifying, Detecting, and Managing RFID Events

Cascadia is a system that provides RFID-based pervasive computing applications with an infrastructure for specifying, extracting and managing meaningful high-level events from raw RFID data. Cascadia provides three important services. First, it allows application developers and even users to specify events using either a declarative query language or an intuitive visual language based on direct manipulation. Second, it provides an API that facilitates the development of applications which rely on RFID-based events. Third, it automatically detects the specified events, forwards them to registered applications and stores them for later use (e.g., for historical queries).We present the design and implementation of Cascadia along with an evaluation that includes both a user study and measurements on traces collected in a building-wide RFID deployment. To demonstrate how Cascadia facilitates application development, we built a simple digital diary application in the form of a calendar that populates itself with RFID-based events. Cascadia copes with ambiguous RFID data and limitations in an RFID deployment by transforming RFID readings into probabilistic events. We show that this approach outperforms deterministic event detection techniques while avoiding the need to specify and train sophisticated models.
Sequence-independent segmentation of magnetic resonance images.

We present a set of techniques for embedding the physics of the imaging process that generates a class of magnetic resonance images (MRIs) into a segmentation or registration algorithm. This results in substantial invariance to acquisition parameters, as the effect of these parameters on the contrast properties of various brain structures is explicitly modeled in the segmentation. In addition, the integration of image acquisition with tissue classification allows the derivation of sequences that are optimal for segmentation purposes. Another benefit of these procedures is the generation of probabilistic models of the intrinsic tissue parameters that cause MR contrast (e.g., T1, proton density, T2*), allowing access to these physiologically relevant parameters that may change with disease or demographic, resulting in nonmorphometric alterations in MR images that are otherwise difficult to detect. Finally, we also present a high band width multiecho FLASH pulse sequence that results in high signal-to-noise ratio with minimal image distortion due to B0 effects. This sequence has the added benefit of allowing the explicit estimation of T2* and of reducing test–retest intensity variability.
Membrane Stresses Induced by Overproduction of Free Fatty Acids in Escherichia coli

Microbially produced fatty acids are potential precursors to high-energy-density biofuels, including alkanes and alkyl ethyl esters, by either catalytic conversion of free fatty acids (FFAs) or enzymatic conversion of acyl-acyl carrier protein or acyl-coenzyme A intermediates. Metabolic engineering efforts aimed at overproducing FFAs in Escherichia coli have achieved less than 30% of the maximum theoretical yield on the supplied carbon source. In this work, the viability, morphology, transcript levels, and protein levels of a strain of E. coli that overproduces medium-chain-length FFAs was compared to an engineered control strain. By early stationary phase, an 85% reduction in viable cell counts and exacerbated loss of inner membrane integrity were observed in the FFA-overproducing strain. These effects were enhanced in strains endogenously producing FFAs compared to strains exposed to exogenously fed FFAs. Under two sets of cultivation conditions, long-chain unsaturated fatty acid content greatly increased, and the expression of genes and proteins required for unsaturated fatty acid biosynthesis were significantly decreased. Membrane stresses were further implicated by increased expression of genes and proteins of the phage shock response, the MarA/Rob/SoxS regulon, and the nuo and cyo operons of aerobic respiration. Gene deletion studies confirmed the importance of the phage shock proteins and Rob for maintaining cell viability; however, little to no change in FFA titer was observed after 24 h of cultivation. The results of this study serve as a baseline for future targeted attempts to improve FFA yields and titers in E. coli.
Thermodynamics Reveal that Helix Four in the NLS of NF-κB p65 Anchors IκBα, Forming a Very Stable Complex

Abstract IκBα is an ankyrin repeat protein that inhibits NF-κB transcriptional activity by sequestering NF-κB outside of the nucleus in resting cells. We have characterized the binding thermodynamics and kinetics of the IκBα ankyrin repeat domain to NF-κB(p50/p65) using surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC). SPR data showed that the IκBα and NF-κB associate rapidly but dissociate very slowly, leading to an extremely stable complex with a KD,obs of approximately 40 pM at 37 °C. As reported previously, the amino-terminal DNA-binding domain of p65 contributes little to the overall binding affinity. Conversely, helix four of p65, which forms part of the nuclear localization sequence, was essential for high-affinity binding. This was surprising, given the small size of the binding interface formed by this part of p65. The NF-κB(p50/p65) heterodimer and p65 homodimer bound IκBα with almost indistinguishable thermodynamics, except that the NF-κB p65 homodimer was characterized by a more favorable ΔHobs relative to the NF-κB(p50/p65) heterodimer. Both interactions were characterized by a large negative heat capacity change (ΔCP,obs), approximately half of which was contributed by the p65 helix four that was necessary for tight binding. This could not be accounted for readily by the small loss of buried non-polar surface area and we hypothesize that the observed effect is due to additional folding of some regions of the complex.
Trends in under-5 mortality rates and the HIV/AIDS epidemic

INTRODUCTION: The prevalence of human immunodeficiency virus (HIV) among adults and mortality rates among under-5-year-olds have increased or stagnated in many countries. The objective of this study was to investigate whether there is a link between under-5 mortality trends and the prevalence of HIV among adults and, if so, to assess the magnitude of the effect of adult HIV prevalence on under-5 mortality rates. METHOD: Data from Demographic and Health Surveys were used to establish the trends in under-5 mortality rates for 25 countries for which there are data for at least two points in time. Countries were ranked according to the most recent adult HIV prevalence data and grouped in three categories: those with very high HIV prevalence (> or = 5%); those with moderately high prevalence (1-4.9%); and those with low prevalence (< 1%). A mathematical model was fitted to obtain an estimate of the contribution of HIV/AIDS to the level of under-5 mortality in each country. RESULTS: Under-5 mortality rates showed an increase in most countries with high adult HIV prevalence, but a decrease in almost every country with moderately high or low prevalence. The estimated contribution of adult HIV prevalence to the observed level of under-5 mortality was highest (up to 61%) in Zimbabwe (where HIV prevalence was highest) and tended to decrease with the level of HIV prevalence. DISCUSSION: The contribution of HIV/AIDS to childhood mortality therefore appears to be most noticeable in settings where the epidemic is most severe.
Employee satisfaction with performance appraisals and appraisers: The role of perceived appraisal use

This study investigates how perceptions of performance appraisal use relate to employee satisfaction with both appraisal and appraiser. The research brings renewed support for the importance of individual development in the performance appraisal process. © 2000 by Jossey-Bass, A Publishing Unit of John Wiley & Sons, Inc.
Treatment of Postoperative Inflammation in Ophthalmology

AbstractAny attempt to understand the rationale behind current approaches used to modify postoperative inflammation following ophthalmic surgery requires an understanding of the pathophysiology of inflammation induced by tissue damage and its relationship to the pharmacodynamics of anti-inflammatory drugs. This review attempts to correlate the pharmacology of antiinflammatory drugs with recent advances in related medical sciences. Antiinflammatory drug actions and uses are reinterpreted from the viewpoint provided by these advances and their relevance to current ophthalmic practice is underscored. An emphasis is placed on the importance of antiinflammatory drug pharmacodynamics and its relationship to ophthalmic therapeutics following ocular surgery. These goals are consistent with the purpose and philosophy of ophthalmic clinical pharmacology.
Exploring technology adoption and use through the lens of residential mobility

One of the outcomes of massive adoption of technology is that much of daily technology use and consumption is embedded into "unremarkable" daily life routines. Occasionally, these routines undergo major shifts, often in conjunction with major life events such as marriage, birth of a child, or a residential move. We propose a model of settling into a new location as a function of balance between the pull of the things left behind and the demands of the new and unknown. It is through this experience of being unsettled that we explore the processes of behavior adjustment and re-evaluation of old patterns of technology use as it relates to the old location and the demands of the new location.
The effect of hospital and surgeon volume on outcomes for rectal cancer surgery

Despite many studies of rectal cancer outcomes, no clear relationship between hospital or surgeon volume and patient outcomes has emerged for rectal cancer. We aimed to characterize the effect of hospital and surgical volume on surgery type and surgical outcomes in rectal cancer through a systematic review of the literature. We conducted a systematic review of studies evaluating the association between hospital or surgeon volume and rectal cancer outcomes. We searched PubMed for relevant articles and reviewed 23 articles. We describe each study and report outcomes in terms of the effect of hospital or surgeon volume on the type of surgery performed, surgical complications, postoperative mortality, survival, and recurrence. Hospitals and surgeons with higher caseloads appear to perform more sphincter-preserving surgeries and have lower postoperative mortality rates. Hospital and surgeon volume appear to have no effect or a small beneficial effect on the rate of leaks, complication rates, local recurrence, overall survival, and cancer-specific survival. For rectal cancer, the effects of hospital volume may be stronger for more short-term outcomes. Beyond the immediate recovery period, the effect of hospital and surgeon volume may be minimal. As more technically challenging surgeries, such as total mesorectal resection, become more widespread it will be important to evaluate the impact of hospital and surgeon volume on outcomes.
Race and ethnicity III Geographies of diversity

Geographic research and our practices in the higher education environment have long been concerned with diversity. Yet diversity is difficult to define and measure, and diversity efforts increasingly go unsupported. Furthermore, geography has been bedeviled by a stubborn lack of meaningful diversity in terms of who we are and what we do. More broadly, multiculturalism and affirmative action oriented toward increasing the numbers and success of underrepresented minorities are largely viewed as failed policies. Thus it has been suggested that diversity has effectively been silenced; alternatively, that it be diversified, or simply waited out. Others seem to view diversity through a hopeful lens, as an aspirational horizon. In this scholarship, encounters across diversity, whether fleeting or more managed, kindle the possibility of curiosity, understanding, and reconciliation.
Stereochemical nature of the products of linoleic acid oxidation catalyzed by lipoxygenases from potato and soybean

When linoleic acid was incubated with the purified potato lipoxygenase under O2 atmosphere, a mixture of 9 and 13-hydroperoxyoctadecadienoic acids was formed. Stereochemical analysis of the respective methyl-hydroxyoctadecadienoic acids revealed that the 9-isomer was in S-configuration whereas 13-hydroxyoctadecadienoic acid was a mixture of S (39%) and R (61%). Exactly the opposite was the case with the soybean lipoxygenase products, where the 13-isomer was found to be in S-configuration and 9-hydroxyoctadecadienoic acid - a mixture of S (73%) and R (27%). A general scheme is proposed for the stereochemical nature of oxidation products of enzymes which are predominantly either [+2] or [-2] lipoxygenases.
A Thermodynamic Study of Electroneutral K-Cl Cotransport in pH- and Volume-Clamped Low K Sheep Erythrocytes with Normal and Low Internal Magnesium

Swelling-induced human erythrocyte K-Cl cotransport is membrane potential independent and capable of uphill transport. However, a complete thermodynamic analysis of basal and stimulated K-Cl cotransport, at constant cell volume, is missing. This study was performed in low K sheep red blood cells before and after reducing cellular free Mg into the nanomolar range with the divalent cation ionophore A23187 and a chelator, an intervention known to stimulate K-Cl cotransport. The anion exchange inhibitor 4,4'diisothiocyanato-2,2'disulfonic stilbene was used to clamp intracellular pH and Cl or NO3 concentrations. Cell volume was maintained constant as external and internal pH differed by more than two units. K-Cl cotransport was calculated from the K effluxes and Rb (as K congener) influxes measured in Cl and NO3, at constant internal K and external anions, and variable concentrations of extracellular Rb and internal anions, respectively. The external Rb concentration at which net K-Cl cotransport is zero was defined as flux reversal point which changed with internal pH and hence Cl. Plots of the ratio of external Rb concentrations corresponding to the flux reversal points and the internal K concentration versus the ratio of the internal and external Cl concentrations (i.e., the Donnan ratio of the transported ions) yielded slopes near unity for both control and low internal Mg cells. Thus, basal as well as low internal Mg-stimulated net K-Cl cotransport depends on the electrochemical potential gradient of KCl.