cssi/SciSciGPT-SciSciNet huggingface dataset:
N-Heterocyclic Carbene-Like Catalysis by a Metal–Organic Framework Material

Metal imidazolates, an important class of constructs in metal–organic framework chemistry, are shown here to be precursors to N-heterocyclic carbene-like catalysts. By using n-butyl lithium to deprotonate tripodal imidazolate framework-1 (TIF-1), N-heterocyclic carbene (NHC) sites can be exposed. These sites are found to be remarkably competent as Bronsted-base-type NHC catalysts. An α,β-unsaturated ketone was converted to the corresponding benzyl ether with benzyl alcohol at a faster rate and in higher yield than with a traditional homogeneous NHC catalyst (1,3-bis-(2,4,6-trimethylphenyl)imidazole)), despite lower overall loading. Varying the size of the alcohol in the conjugate addition reaction yielded no change in reaction rate, even when the size of the alcohol exceeded the diameter of the MOF pores, suggesting that catalysis occurs exclusively on the surface of the MOF crystals, as opposed to within the framework pores.
A flexible, large-scale, distributed agent based epidemic model

We describe a distributed agent based epidemic model that is capable of easily simulating several hundred million agents. The model is adaptable to shared-memory and distributed-memory architectures. Several problems are addressed to enable the distributed simulation: allocation of agents to available compute nodes, periodic synchronization of compute nodes, and efficient communication between compute nodes. We assert that our modeling scheme is easily adaptable to different hardware environments and does not require large investments in performance tuning or special case coding.
Stochastic modeling of integrated power system coupled to hydrodynamics in the all-electric ship

In the paper, we model the integrated power system (IPS) of a typical destroyer ship coupled to hydrodynamics. This IPS is composed of a 21 MW, 3-phase synchronous generator supplying electric power to 4160 V AC bus and to a 19 MW, 15-phase induction motor driven by an indirect rotor field oriented control for the motor torque. Moreover, stochastic responses are examined when there exists a variation in the induction motorpsilas rotor resistance and a disturbance from the slowly-varying added resistance, derived from a Pierson and Moskowitz sea spectrum.
Hydrologic characterization of reservoir metagraywacke from shallow and deep levels of The Geysers vapor-dominated geothermal system, California, USA

Abstract Hydrologic and geochemical properties were measured on metagraywacke plug samples of matrix rock from shallow and deep cores from The Geysers geothermal field. Gas permeability ranged from 2×10 −22 to 4×10 −20 m 2 and Klinkenberg slip factor ranged from 1 to 20 MPa. Porosities ranged from 1.9 to 2.2%. Capillary-pressure curves were measured and van Genuchten fitting parameters were used to estimate relative-permeability curves. Shallow samples were weakly altered, but deeper ones were intensely altered and mineralized to chlorite, secondary potassium feldspar and various calc-silicate minerals. Deeper samples were more permeable, and this difference is related to chlorite–potassium feldspar alteration and related porosity enhancement.
False‐negative core needle biopsies of the breast

BACKGROUND A benign diagnosis in a core needle biopsy (CNBx) of the breast performed for a clinically and/or radiologically suspicious abnormality is often due to a nonrepresentative sample. However, the discordance may not be recognized, resulting in a logistic delay in the diagnosis. METHODS Twenty-seven false-negative CNBxs were identified in 952 consecutive CNBxs of the breast (653 benign, 266 malignant, and 33 atypical) performed during a 1-year period. Biopsies were analyzed with respect to clinical and radiologic findings, biopsy type, type of malignancy, and interval between the original CNBx and final diagnosis. Four hundred thirty-eight (67%) of the patients with a benign CNBx diagnosis either underwent excision or had a minimum of 1-year follow-up (mean, 35.6 months; median, 36 months). RESULTS The cancers missed on CNBx included 6 ductal carcinomas in situ, 17 invasive ductal carcinomas, 3 invasive lobular carcinomas, and 1 non-Hodgkin lymphoma. The overall false-negative rate was 9.1%. For palpable lesions, ultrasound-guided CNBx had a lower rate of missed cancer (3.6%) compared with CNBx without image guidance (13.3%). The false-negative rate for vacuum assisted CNBx biopsy was 7.6% (3.3% for the 11-gauge needle, 22.2% for the 14-gauge needle; 5.6% for nonpalpable mass lesions, 8.2% for microcalcifications). In all seven false-negative CNBxs performed by radiologists, the discordance between the radiologic and pathologic findings was promptly recognized due to their standard follow-up protocol. The discordance between the degree of clinical suspicion, radiologic impression, and the pathologic findings was not immediately recognized in 5 of 20 false-negative CNBxs performed by surgeons (4 without radiologic guidance and 1 with ultrasound guidance), resulting in a delay in the diagnosis ranging from 112–336 days. CONCLUSIONS A false-negative diagnosis of breast carcinoma was found to be more common in CNBx performed without image guidance but occurred to a lesser degree in image-guided biopsies. A delay in diagnosis can be avoided by establishing a standard post-CNBx follow-up protocol. Cancer 2003;97:1824–31. © 2003 American Cancer Society. DOI 10.1002/cncr.11278
Tissue Temperature Oscillations in an Isolated Pig Kidney During Surface Heating

In the present study, an isolated pig kidney was used to study tissue temperature oscillations due to vascular thermoregulation, frequently observed during hyperthermia treatments. The kidney was perfused with the distilled water pumped through the renal artery to simulate blood flow. When the local perfusion rate was increased with a time delay, temperature oscillations were observed in the kidney as its surface temperature raised linearly with time in a water bath. The magnitude of tissue temperature decreased as the flow rate increased during the surface heating. A 3D transient model was developed to predict the temperature oscillations, which was validated by the measurements. Using the model, relationships of the changes in perfusion rate and heating rate with temperature oscillations were investigated. It was found that the heating rate, and the magnitude and time delay of the flow response to the temperature elevation, each significantly affected tissue temperature oscillations. The magnitude of oscillation was primarily determined by the spatial gradient of temperature, while the oscillation type depended on the change of flow rate and the time delay. In conclusion, to accurately predict and control the tissue temperature distribution during hyperthermia treatment, understanding of the local perfusion change with respect to tissue temperature is essential.
Cryptic variation in electrophoretically-detected allozymes of caddisfly larvae (Hydropsyche simulans, Hydropsyche bifida) and spotfin shiners (Notropis spilopterus): Implications for allele and genotype determinations

Abstract Electrophoretic patterns of certain allozymes for the same individuals of Hydropsyche simulans, Hydropsyche bifida and Notropis spilopterus varied between gel types. A new scoring protocol combined the results of scores from both gel types to include cryptic variation in the ultimate allele and genotype designations. Cryptic variation, when detected, may provide a more accurate measure of electrophoretically-detected genetic variability than single-gel protocols.
Productive Activity, Accumulation, and Growth in Postwar Japan and the United States

This empirical study shows that the more rapid postwar economic growth in Japan in comparison to the United States was influenced neither by the higher level nor faster growth of its rate of surplus value, but by less surplus value having been absorbed by unproductive expenditures. Also the slowdown of Japan's growth and the precipitous decline in its profitability after 1970 was not the result of a profit-squeeze due to a falling rate of surplus value, since the Japanese rate of surplus value (like that of the United States) rose over the period
Effective interactions in an oxygen-hole metal

We study the properties of an effective Hamiltonian to describe the propagation of holes through the oxygen anion network in a high-${T}_{c}$ superconductor. Approximate parameters for our Hamiltonian are derived from atomic properties of O. The effective interaction between holes and the effective bandwidth for the holes are studied by diagonalization of finite clusters. The effective interaction is found to be attractive for realistic parameters; in the same regime, there is significant band narrowing. Consequences of our results for normal and superconducting properties of high-${T}_{c}$ oxides are discussed.
Growth hormone-release inhibiting hormone (GH-RIH) pathway of the rat hypothalamus revealed by the unlabeled antibody peroxidase-antiperoxidase method.

Utilizing the unlabeled antibody enzyme method, we investigated the distribution of hypothalamic elements immunoreactive with antibodies to growth hormonerelease inhibiting hormone (GH-RIH). Immunostained elements, resembling neural processes, are distributed along a pathway corresponding to a portion of the tuberoinfundibular tract. However, GH-RIH fibers are caudal, dorsal and medial to LH-RH fibers detected by the same technique. Similar topographic arrangements are noted in coronal and sagittal sections. Comparable results were obtained with two different preparations of antisera to GH-RIH. No cell bodies specifically stained by anti-GH-RIH were detected. Our data agree with those of other investigators using immunohistochemical techniques.
THE ROLE OF INDEPENDENT VARIABLE INTEGRITY IN THE BEHAVIORAL MANAGEMENT OF TOURETTE SYNDROME

We examined the effects of self-monitoring, dissimilar response practice, and competing response practice on the tics of two preadolescent males with Tourette Syndrome. Tic frequencies were assessed using an alternating treatments design over the course of approximately 1 month. The data indicate that neither of the participants’ tics changed as a result of the interventions. Upon examination of independent variable integrity data, we noticed that the participants were not implementing the treatments as instructed. The results are discussed in the context of improving the research methodology in this area, particularly with respect to independent variable integrity measures.
Elastic scattering and polarization of high-energy nucleons by nuclei

The cross section and polarization for the elastic scattering of protons by carbon and lead at 135 MeV and by carbon at 300 MeV have been evaluated in the impulse approximation using the nucleon-nucleon phase-shift sets of Signell-Marshak, Gammel-Thaler, Ohnuma-Feldman, and Stapp. The detailed calculations have been carried out both in ordinary Born approximation and also in terms of a modified Born approximation in which account is taken of the absorption of the elastically scattered nucleon wave within the nucleus. Relativistic effects have been estimated and have been found to be small. The possibility of distinguishing among the various sets of nucleon-nucleon phase shifts is discussed.
Inner retinal oxygen delivery and metabolism in streptozotocin diabetic rats.

Purpose. The purpose of the study is to report global measurements of inner retinal oxygen delivery (DO2_IR) and oxygen metabolism (MO2_IR) in streptozotocin (STZ) diabetic rats.
Kirsch, I. (2010). The Emperor's New Drugs: Exploding the Antidepressant Myth. New York: Basic Books. Reviewed by Sharon B. Spiegel, Ph.D., ABPP, Bethesda MD

(2011). Kirsch, I. (2010). The Emperor's New Drugs: Exploding the Antidepressant Myth. New York: Basic Books. Reviewed by Sharon B. Spiegel, Ph.D., ABPP, Bethesda MD. American Journal of Clinical Hypnosis: Vol. 53, No. 3, pp. 229-231.
Model reference adaptive inverse control of a single link flexible robot

Abstract A new model reference adaptive inverse control algorithm is proposed for the end point position control of flexible manipulators. This controller forms a series model reference adaptive system where an estimated system inverse is placed in the feed forward path to provide an inverse control through regulation of controller parameters. It differs from other model reference control strategies in that a signal synthesis loop is included to compensate for the estimation error of the inverse controller and the output tracking error, and to improve stability. The stability of the overall control system is shown to be guaranteed using hyperstability theory. The proposed control scheme is applied to control the tip position of a single link flexible robot. A non-dimensionalized model is developed. Its zero-order hold equivalence in discrete time domain is described by an auto-regressive and moving average form. A lattice filter is utilized as a deconvolution filter. The time-delay behavior from the driving torque to the robot tip position due to robot structural flexibility is investigated.
Electrowetting of Room Temperature Ionic Liquids (RTILs) for Capillary Force Manipulation

The feasibility of using room temperature ionic liquids (RTILs) as the electrowetting liquid for capillary force microgrippers was studied. The non-volatility and thermal stability of ionic liquids make them suitable for droplet based microgripping application in high temperature and vacuum environments. Electrowetting on co-planar electrodes was utilized to dynamically change the contact angle of a 1-butyl-3-methylimidazolium hexafluorophosphate (BmimPF6 ) liquid bridge to control the capillary lifting forces. The lifting force generated by the liquid bridge was experimentally characterized. The maximum capillary force was 146μN. The dynamic response of the BmimPF6 liquid bridge was also characterized.Copyright © 2009 by ASME
Computing bounded ε-reach set with finite precision computations for a class of linear hybrid automata

In a previous paper [7] we have identified a special class of linear hybrid automata, called Deterministic Transversal Linear Hybrid Automata, and shown that an e-reach set up to a finite time, called a bounded e-reach set, can be computed using infinite precision calculations. However, given the linearity of the system and the consequent presence of matrix exponentials, numerical errors are inevitable in this computation. In this paper we address the problem of determining a bounded e-reach set using variable finite precision numerical approximations. We present an algorithm for computing it that uses only such numerical approximations. We further develop an architecture for such bounded e-reach set computation which decouples the basic algorithm for an e-reach set with given parameter values from the choice of several runtime adaptation needed by several parameters in the variable precision approximations.
An Online Tutorial for SciFinder for Organic Chemistry Classes

An online tutorial for SciFinder, the premier database for searching the chemical literature, was created by a team consisting of the science librarian, the systems librarian, and a chemistry professor at Rider University using Adobe Captivate 4 software. It was then used by two sections of an Organic Chemistry class during the spring 2010 semester. Traditionally, the science librarian has demonstrated this resource in a single, twenty- to thirty-minute session during class time. However, time constraints pose numerous obstacles for direct library instruction, allowing no time for hands-on practice afterward. The online tutorial for SciFinder was designed to teach students how to search for relevant, scholarly articles, and how to retrieve these articles from the university library or those of neighboring institutions, obviating the need for the customary classroom instruction that taught those skills. To encourage the students to follow the tutorial and develop their SciFinder skills, they were further r...
The Influence of Snowmobile Trails on Coyote Movements during Winter in High-Elevation Landscapes

Competition between sympatric carnivores has long been of interest to ecologists. Increased understanding of these interactions can be useful for conservation planning. Increased snowmobile traffic on public lands and in habitats used by Canada lynx (Lynx canadensis) remains controversial due to the concern of coyote (Canis latrans) use of snowmobile trails and potential competition with lynx. Determining the variables influencing coyote use of snowmobile trails has been a priority for managers attempting to conserve lynx and their critical habitat. During 2 winters in northwest Wyoming, we backtracked coyotes for 265 km to determine how varying snow characteristics influenced coyote movements; 278 km of random backtracking was conducted simultaneously for comparison. Despite deep snow (>1 m deep), radio-collared coyotes persisted at high elevations (>2,500 m) year-round. All coyotes used snowmobile trails for some portion of their travel. Coyotes used snowmobile trails for 35% of their travel distance (random: 13%) for a mean distance of 149 m (random: 59 m). Coyote use of snowmobile trails increased as snow depth and penetrability off trails increased. Essentially, snow characteristics were most influential on how much time coyotes spent on snowmobile trails. In the early months of winter, snow depth was low, yet the snow column remained dry and the coyotes traveled off trails. As winter progressed and snow depth increased and snow penetrability increased, coyotes spent more travel distance on snowmobile trails. As spring approached, the snow depth remained high but penetrability decreased, hence coyotes traveled less on snowmobile trails because the snow column off trail was more supportive. Additionally, coyotes traveled closer to snowmobile trails than randomly expected and selected shallower snow when traveling off trails. Coyotes also preferred using snowmobile trails to access ungulate kills. Snow compaction from winter recreation influenced coyote movements within an area containing lynx and designated lynx habitat.
Silver(I)/persulfate oxidative decarboxylation of carboxylic acids. Arylacetic acid dimerization.

Abstract The oxidative decarboxylation of arylacetic acids by sodium persulfate and a catalytic amount of silver nitrate produces benzylic radicals which dimerize cleanly to give 1,2-diarylethanes.
CB1 and CB2 receptors are novel molecular targets for Tamoxifen and 4OH-Tamoxifen

Tamoxifen (Tam) is classified as a selective estrogen receptor modulator (SERM) and is used for treatment of patients with ER-positive breast cancer. However, it has been shown that Tam and its cytochrome P450-generated metabolite 4-hydroxy-Tam (4OH-Tam) also exhibit cytotoxic effects in ER-negative breast cancer cells. These observations suggest that Tam and 4OH-Tam can produce cytotoxicity via estrogen receptor (ER)-independent mechanism(s) of action. The molecular targets responsible for the ER-independent effects of Tam and its derivatives are poorly understood. Interestingly, similar to Tam and 4OH-Tam, cannabinoids have also been shown to exhibit anti-proliferative and apoptotic effects in ER-negative breast cancer cells, and estrogen can regulate expression levels of cannabinoid receptors (CBRs). Therefore, this study investigated whether CBRs might serve as novel molecular targets for Tam and 4OH-Tam. We report that both compounds bind to CB1 and CB2Rs with moderate affinity (0.9-3 μM). Furthermore, Tam and 4OH-Tam exhibit inverse activity at CB1 and CB2Rs in membrane preparations, reducing basal G-protein activity. Tam and 4OH-Tam also act as CB1/CB2R-inverse agonists to regulate the downstream intracellular effector adenylyl cyclase in intact cells, producing concentration-dependent increases in intracellular cAMP. These results suggest that CBRs are molecular targets for Tam and 4OH-Tam and may contribute to the ER-independent cytotoxic effects reported for these drugs. Importantly, these findings also indicate that Tam and 4OH-Tam might be used as structural scaffolds for development of novel, efficacious, non-toxic cancer drugs acting via CB1 and/or CB2Rs.
Iron absorption and bioavailability : An updated review

Regulation of iron absorption operates at the level of duodenal mucosal cells. Despite much research, the specific biochemical pathways of iron absorption and the regulatory mechanisms controlling it remain unknown. This review summarizes current knowledge of and hypotheses on each of the three steps of iron absorption: uptake from the intestinal lumen into mucosal cells, transit through the cell, and release from the cells into the body. Absorption may be defined as the movement of iron from the intestinal lumen across the epithelial cells of the digestive tract into the circulation, while bioavailability generally refers to the proportion of iron in a given food or diet that the body can actually utilize. The most common technique of measuring iron absorption and bioavailability, extrinsic radiolabeling of a single meal, is discussed in the context of the latest studies using this methodology.
Two phylogenetic specializations in the human brain.

In this study, two anatomical specializations of the brain in apes and humans are considered. One of these is a whole cortical area located in the frontal polar cortex (Brodmann’s area 10), and the other is a morphologically distinctive cell type, the spindle neuron of the anterior cingulate cortex. The authors suggest that the spindle cells may relay to other parts of the brain—especially to area 10, the outcome of processing within the anterior cingulate cortex. This relay conveys the motivation to act. It particularly concerns the recognition of having committed an error that leads to the initiation of adaptive responses to these adverse events so as to reduce error commission. This capacity is related to the development of self-control as an individual matures and gains social insight. Although the anterior cingulate deals with the individual’s immediate response to changing conditions, area 10 is involved in the retrieval of memories from the individual’s past experience and the capacity to plan adap...
Quantum energy flow and trans-stilbene photoisomerization: an example of a non-RRKM reaction

We apply multireference ab initio quantum chemistry and microcanonical transition state (RRKM) theory with quantum energy flow corrections from local random matrix theory (LRMT) to determine the kinetics of trans-stilbene photoisomerization. With a single ab initio potential energy surface and no adjustable parameters, simultaneous agreement with experiment of the microcanonical isomerization rates for the d0, d2, d10, and d12 isotopomers is obtained. We are also able to reproduce the pressure dependence of the thermal rate. Laser cooling effects on the isomerization rate are calculated and found to be quite small. The S1/S2 energy gap at the transition state is found to be quite large (0.86 eV), suggesting that nonadiabatic effects are negligible. Using the ab initio results in a simple RRKM theory without corrections for finite quantum energy flow does not lead to agreement with experiment. We conclude that non-RRKM effects are essential to understand photoisomerization of trans-stilbene and that these ...
Incorporation of C14-amino acids into proteins of leaf disks and cell-free fractions of tobacco leaves.

Abstract Incorporation of C 14 -labeled amino acids takes place into the proteins of intact leaf disks and cell-free extracts of tobacco leaves. When isolated cell fractions are incubated with labeled amino acid, incorporation into the chloroplast protein, although no more rapid than incorporation into other fractions, continues for a longer time. It is shown that this incorporation is not due to bacteria. Oxygen and light stimulate incorporation into the chloroplast fraction. This finding provides evidence for a coupling of photosynthetic energy to protein synthesis under cell-free conditions. The RNA-rich microsomal fraction shows the most rapid rate of incorporation in the first few minutes, and is therefore implicated as an initial site of incorporation of amino acids into protein. Although tobacco mosaic virus becomes labeled during incubation of intact cells with C 14 -amino acids, there is no synthesis of virus in these cell-free preparations of infected leaves.
Hindlimb Suspension and SPE-Like Radiation Impairs Clearance of Bacterial Infections

A major risk of extended space travel is the combined effects of weightlessness and radiation exposure on the immune system. In this study, we used the hindlimb suspension model of microgravity that includes the other space stressors, situational and confinement stress and alterations in food intake, and solar particle event (SPE)-like radiation to measure the combined effects on the ability to control bacterial infections. A massive increase in morbidity and decrease in the ability to control bacterial growth was observed using 2 different types of bacteria delivered by systemic and pulmonary routes in 3 different strains of mice. These data suggest that an astronaut exposed to a strong SPE during extended space travel is at increased risk for the development of infections that could potentially be severe and interfere with mission success and astronaut health.
A method of polymerizing and fabricating large plastic scintillators

Abstract A method is described by which large pieces of scintillating plastic for use as anti-Compton shields may be produced in the laboratory at a small fraction of the cost for a similar commercial system. The method is safer and requires less machining than standard methods.
Improve signal integrity performance by using hybrid PCB stackup

FR4 is a commonly used material in industry to build printed circuit boards. However signals propagating in this media have significant attenuation when date rate gets higher and higher, gating the solution space. Low loss materials can be considered to enable longer board routing but they are very costly for most of commercial platforms. In this paper, hybrid PCB stackup is investigated. The investigation focuses on full channel signal integrity analysis. Simulations for SATA3 and PCIE3 show noticeable improvement of using this hybrid stackup. Such a hybrid is normally less costly than all low loss PCB stackup, thus achieving a good compromising between cost and performance for PCB design and manufacturing.
Practical risk aggregation in RBAC models

This paper describes our system, built as part of a commercially available product, for inferring the risk in an RBAC policy model, i.e., the assignment of permissions to roles and roles to users. Our system implements a general model of risk based on any arbitrary set of properties of permissions and users. Our experience shows that fuzzy inferencing systems are best suited to capture how humans assign risk to such assignments. To implement fuzzy inferencing practically we need the axiom of monotonicity, i.e., risk can not decrease when more permissions are assigned to a role or when the role is assigned to fewer users. We describe the visualization component which administrators can use to infer aggregate risk in role assignments as well as drill down into which assignments are actually risky. Administrators can then use this knowledge to refactor roles and assignments.
Oscillations in the basal ganglia under normal conditions and in movement disorders

A substantial body of work within the last decade has demonstrated that there is a variety of oscillatory phenomena that occur in the basal ganglia and in associated regions of the thalamus and cortex. Most of the earlier studies focused on recordings in rodents and primates. More recently, significant advances have been made in this field of research through the analysis of basal ganglia field potentials recorded from implanted deep brain stimulation electrodes in the basal ganglia of human patients with Parkinson's disease and other disorders. It now appears that oscillatory activity may play a significant role in the pathogenesis of these diseases. The most significant finding is that in Parkinson's disease synchronized oscillatory activity in the 10- to 35-Hz band (often termed "beta-band") is prevalent in the basal ganglia-thalamocortical circuits, and that such activity can be reduced by dopaminergic treatments. The entrainment of large portions of these circuits may disrupt information processing in them and may lead to parkinsonian akinesia (and perhaps tremor). Although less firmly established than the role of oscillations in movement disorders, oscillatory activities at higher frequencies may also be a component of normal basal ganglia physiology.
Electrical aversion therapy with alcoholics: an analogue study.

Abstract Chronic alcoholic patients matched on age, education and length of problem drinking were assigned to one of three treatment conditions, with 10 subjects in each group: (1) Electrical Aversion Conditioning (high shock paired with alcohol sips); (2) Control Conditioning (very low shock paired with alcohol sips); and (3) Group Therapy (confrontation psychotherapy). Groups 2 and 3 were included to control for possible ‘attention-placebo’ and expectancy factors involved in the conditioning procedures. Subjects in each group were given instructions designed to produce high expectancy for therapeutic success. Pre-post measures of alcohol consumption and attitudes toward alcohol were obtained using an analogue ‘taste test’ assessment procedure. No statistically significant differences in reduced alcohol consumption or attitudes toward alcohol were found among the groups. Trends in the data support the contention that effects of electrical aversion may be more related to such factors as therapeutic instructions, expectancy, specificity of the procedure or experimental demand characteristics than to conditioning factors.
Kinetics and Mechanism of the Complex Bromate−Iodine Reaction1

The mechanism of the reaction between bromate and iodine in an acidic medium (HClO4), in a closed system, has been investigated by both experimental and computer simulation techniques. The stoichiometry of the reaction is 2BrO3- + I2 → 2IO3- + Br2. The reaction is preceded by an induction period whose length is inversely proportional to the concentration of bromate and the square of the acid concentration. The induction period increases upon the addition of iodide and bromide ions, with the effect of bromide ions being less marked. These ions consume HOI and HOBr molecules, which are precursors to the oxidation of iodine. At the end of the induction period iodine is suddenly depleted while simultaneously a transient interhalogen, iodine bromide, IBr, is formed and consumed rapidly. As soon as the IBr concentration reaches its maximum value, i.e., [IBr]max = 2[I2]0, it is rapidly consumed at an exponential rate given by −d[IBr]/dt = k1[IBr]. When all the IBr has been depleted, molecular bromine is formed a...
Characterization of Hot-Wire Detonators Using Analytical Modeling and Computational Tools

An effort is underway to determine the electromagnetic (EM) characteristics of hot-wire detonators to quantify the possible effects of EM radiation. The analyses include a comprehensive investigation of physical detonator characteristics, which is then used to model detonators using EM theory and numerical simulations. The theoretical analysis treats the detonator as a cascaded transmission line incorporating several different dielectric regions, and examines both differential and common mode excitation. In addition, the detonator is modeled and simulated using ICEPIC (Improved Concurrent electromagnetic particle in cell), a finite-difference-time-domain (FDTD) EM solver. The cascaded transmission line model is then augmented with additional circuit elements whose values are found using ICEPIC. This combination produces a refined transmission line model that is implemented in MATLAB and can be run quickly for a wide range of detonators to determine possible deviations in radio frequency (RF) response due to manufacturing variations. A detailed RF response is not a given specification for detonators and, therefore, it is not a characteristic that is controlled during manufacturing. The results of both the analytic and computational methods, including detonator input impedance and resonant frequencies, are compared.
Highly reliable analog filter design using analog voting

N-Modular Redundancy (NMR) is the most commonly used failure mitigation technique, in which a voting unit is used to vote out the wrong path/data. The voter is, therefore, vital for nanoscale analog and digital circuits in which high defect rate is expected. In this paper, we propose a redundancy based fault-tolerant methodology to design fault tolerant analog filters. The key contribution of our work is an innovative mean voter which is very fast, inexpensive and linearly scalable with respect to the redundancy factor. For the proof of concept, we designed a 4th order high frequency Gm-C filter and a 5th order Opamp-RC filter and reported the circuits reliability.
Dual state-parameter estimation of hydrological models using ensemble Kalman filter

Hydrologic models are twofold: models for understanding physical processes and models for prediction. This study addresses the latter, which modelers use to predict, for example, streamflow at some future time given knowledge of the current state of the system and model parameters. In this respect, good estimates of the parameters and state variables are needed to enable the model to generate accurate forecasts. In this paper, a dual state–parameter estimation approach is presented based on the Ensemble Kalman Filter (EnKF) for sequential estimation of both parameters and state variables of a hydrologic model. A systematic approach for identification of the perturbation factors used for ensemble generation and for selection of ensemble size is discussed. The dual EnKF methodology introduces a number of novel features: (1) both model states and parameters can be estimated simultaneously; (2) the algorithm is recursive and therefore does not require storage of all past information, as is the case in the batch calibration procedures; and (3) the various sources of uncertainties can be properly addressed, including input, output, and parameter uncertainties. The applicability and usefulness of the dual EnKF approach for ensemble streamflow forecasting is demonstrated using a conceptual rainfall-runoff model. 2004 Elsevier Ltd. All rights reserved.
The Testing of Aircraft Thermometers

IT has become increasingly obvious that however good the thermometers may be in an aeroplane, they are liable to errors—sometimes quite large ones—as a result of vibration, fatigue or plain accidental damage. It seems quite likely that on operational machines an error, as long as it is constant, is of no great importance; as most pilots look for variations in their normal readings, rather than judge by the readings themselves, and, therefore, it is probably sufficient if any instrument that is obviously suspect is tested, and the others are‐taken as satisfactory.
Sexual reproduction selects for robustness and negative epistasis in artificial gene networks

The origin and persistence of sexual reproduction in living organisms remains one of the deepest mysteries of biology. Although several plausible theories have been proposed, they make predictions that are hard to test in real life. But an experiment run in an artificial gene network model shows that a condition postulated by a leading theory, the mutation deterministic hypothesis, may evolve more easily than was thought. The condition, negative epistasis, is one in which gene mutations are more harmful when combined in the same genome than when separate. In fact the model suggests that negative epistasis can actually evolve as a consequence of sexual reproduction itself. The mutational deterministic hypothesis for the origin and maintenance of sexual reproduction posits that sex enhances the ability of natural selection to purge deleterious mutations after recombination brings them together into single genomes1. This explanation requires negative epistasis, a type of genetic interaction where mutations are more harmful in combination than expected from their separate effects. The conceptual appeal of the mutational deterministic hypothesis has been offset by our inability to identify the mechanistic and evolutionary bases of negative epistasis. Here we show that negative epistasis can evolve as a consequence of sexual reproduction itself. Using an artificial gene network model2,3, we find that recombination between gene networks imposes selection for genetic robustness, and that negative epistasis evolves as a by-product of this selection. Our results suggest that sexual reproduction selects for conditions that favour its own maintenance, a case of evolution forging its own path.
New algorithm to enable 400+ TFlop/s sustained performance in simulations of disorder effects in high-T c superconductors

Staggering computational and algorithmic advances in recent years now make possible systematic Quantum Monte Carlo (QMC) simulations of high temperature (high-Tc) superconductivity in a microscopic model, the two dimensional (2D) Hubbard model, with parameters relevant to the cuprate materials. Here we report the algorithmic and computational advances that enable us to study the effect of disorder and nano-scale inhomogeneities on the pair-formation and the superconducting transition temperature necessary to understand real materials. The simulation code is written with a generic and extensible approach and is tuned to perform well at scale. Significant algorithmic improvements have been made to make effective use of current supercomputing architectures. By implementing delayed Monte Carlo updates and a mixed single-/double precision mode, we are able to dramatically increase the efficiency of the code. On the Cray XT4 systems of the Oak Ridge National Laboratory (ORNL), for example, we currently run production jobs on 31 thousand processors and thereby routinely achieve a sustained performance that exceeds 200 TFIop/s. On a system with 49 thousand processors we achieved a sustained performance of 409 TFIop/s. We present a study of how random disorder in the effective Coulomb interaction strength affects the superconducting transition temperature in the Hubbard model.
Quo vadis elasticity imaging

In the past decade, an important field that has emerged as complementary to ultrasonic imaging is that of elasticity imaging. The term encompasses a variety of techniques that can depict a mechanical response or property of tissues. In ultrasound, its premise is built on two important facts: (a) that significant differences between mechanical properties of several tissue components exist and (b) that the information contained in the coherent scattering, or speckle, is sufficient to depict these differences following an external or internal mechanical stimulus. Parameters, such as velocity of vibration, displacement, strain, strain rate, velocity of wave propagation and elastic modulus, have all been demonstrated feasible in their estimation and have resulted in the accurate depiction of stiffer tissue masses, such as tumors, high-intensity focused ultrasound (HIFU) lesions and atherosclerotic plaques. More recently, through the development of ultrafast algorithms tailored to suitable hardware as well as the familiarity of the physician with the sensitivity of the methods used, one elasticity imaging technique in particular, elastography, has been shown applicable in a typical clinical ultrasound setting. In other words, elastograms can currently be obtained at quasi real-time (approximately at a frame rate of 8 frames/s) and with the use of a hand-held transducer (as opposed to the previously used frame-suspended setup) during and simultaneously with an ultrasound exam of, e.g., the breast or the prostate. The higher frame rate available with certain clinical ultrasound scanners has also resulted in the successful application of elasticity imaging techniques on the myocardium and monitoring its deformation over several cardiac cycles for the detection of ischemic regions. As a result, elasticity imaging with its ever increasing number of applications and demonstrated applicability in a typical, clinical ultrasound setting promises to make an important contribution to the ultrasound practice as we know it.
A HARMONIC BALANCE APPROACH FOR MODELING THREE-DIMENSIONAL NONLINEAR UNSTEADY AERODYNAMICS AND AEROELASTICITY

Presented is a frequency domain harmonic balance (HB) technique for modeling nonlinear unsteady aerodynamics of three-dimensional transonic inviscid flows about wing configurations. The method can be used to model efficiently nonlinear unsteady aerodynamic forces due to finite amplitude motions of a prescribed unsteady oscillation frequency. When combined with a suitable structural model, aeroelastic (fluid-structure), analyses may be performed at a greatly reduced cost relative to time marching methods to determine the limit cycle oscillations (LCO) that may arise. As a demonstration of the method, nonlinear unsteady aerodynamic response and limit cycle oscillation trends are presented for the AGARD 445.6 wing configuration. Computational results based on the inviscid flow model indicate that the AGARD 445.6 wing configuration exhibits only mildly nonlinear unsteady aerodynamic effects for relatively large amplitude motions. Furthermore, and most likely a consequence of the observed mild nonlinear aerodynamic behavior, the aeroelastic limit cycle oscillation amplitude is predicted to increase rapidly for reduced velocities beyond the flutter boundary. This is consistent with results from other time-domain calculations. Although not a configuration that exhibits strong LCO characteristics, the AGARD 445.6 wing nonetheless serves as an excellent example for demonstrating the HB/LCO solution procedure.
THERMODYNAMICS OF NUCLEATION AND GROWTH

Nucleation and growth are often discussed in terms of kinetics, i.e. the adsorption of atoms from the gas phase or a solution onto a surface, the diffusion of these atoms on that surface, and their attachment to a growing nucleus, island or layer. In recent years, scanning tunneling and atomic force microscopy studies have tremendously improved our understanding of such kinetic processes for a wide range of materials. At relatively low temperatures where diffusion is slow, and where typical deposition rates result in adatom concentrations that far exceed the equilibrium concentration of adatoms on the surface, growth is indeed controlled by irreversible atomic scale kinetics. But at higher temperatures this is not necessarily the case. Indeed, the equilibrium concentration of adatoms can be so high that it is only slightly increased by an external flux. Diffusion can be so fast that spatially separated regions on the surface interact on a time scale that is not slow relative to the growth process. In such cases reversible, collective phenomena are more important than individual atomic events, and thermodynamics is more important than kinetics. In this paper we examine a number of cases related to nucleation and growth on surfaces, where a deep and quantitative insight into the growth process can be obtained by detailed consideration of the thermodynamics involved. It is our hope that this paper will help to bring about a balanced understanding of these phenomena, where kinetics and thermodynamics are two poles on a continuum with an importance that depends on the particulars of each experiment.
Platinum thin film anodes for solid acid fuel cells

Hydrogen electro-oxidation kinetics at the Pt | CsH2PO4 interface have been evaluated. Thin films of nanocrystalline platinum 7.5–375 nm thick and 1–19 mm in diameter were sputtered atop polycrystalline discs of the proton-conducting electrolyte, CsH2PO4, by shadow-masking. The resulting Pt | CsH2PO4 | Pt symmetric cells were studied under uniform H2-H2O-Ar atmospheres at temperatures of 225–250 °C using AC impedance spectroscopy. For thick platinum films (>50 nm), electro-oxidation of hydrogen was found to be limited by diffusion of hydrogen through the film, whereas for thinner films, diffusion limitations are relaxed and interfacial effects become increasingly dominant. Extrapolation to vanishing film thickness implies an ultimate interfacial resistivity of 2.2 Ω cm2, likely reflecting a process at the Pt | H2(g) interface. Films 7.5 nm in thickness displayed a total electro-oxidation resistivity, , of 3.1 Ω cm2, approaching that of Pt-based composite anodes for solid acid fuel cells (1–2 Ω cm2). In contrast, the Pt utilization (−1/Pt loading), 19 S mg−1, significantly exceeds that of composite electrodes, indicating that the thin film approach is a promising route for achieving high performance in combination with low platinum loadings.
The Optimal Design of First-Price Auctions with Financial Constraints and Default Risks

If the bidders in an auction have financial constraints, how should the seller design the auction to maximize his profit? An observed practice is that the seller offers a loan, or interest subsidy, to the highest bidder. The work by Che and Gale [3] has given a partial answer for second-price auctions, with default risk assumed away. This paper provides a complete solution for first-price auctions, with default risk included. For each level of the interest subsidy, we solve the auction game and give a closed form solution for its symmetric equilibrium.
Distances in an array: an alternative description for large scale network topology

In the complete graph on an (m, n) array, methods are given for finding how many links have a given length and for finding the average length of a link. A method is also given for finding the average length of a link in a graph where there is an upper bound on the length of a link. >
VIGvisual: A Visualization Tool for the Vigenère Cipher

This paper describes a visualization tool VIGvisual that helps students learn and instructors teach the Vigenere cipher. The software allows the user to visualize both encryption and decryption through a variety of cipher tools. The demo mode is useful and efficient for classroom presentation. The practice mode allows the user to practice encryption and decryption. VIGvisual is quite versatile, providing support for both beginners learning how to encrypt and decrypt, and also for the more advanced users wishing to practice cryptanalysis in the attack mode. Classroom evaluation of the tool was positive.
Adaptive Correction to Array Coefficients Through Dithering and Near-Field Sensing

Adaptive correction of the excitation coefficients of a phased array achieved through dithering the magnitudes and phases of the element coefficients and sensing the fields through a near-zone probe is demonstrated by considering a linear array. Knowledge of the reference signal generated by the desired array at the near-zone probe is assumed. Deviations in the coefficients of the actual array from the desired array are corrected adaptively and simultaneously by means of a gradient based algorithm. Requirements for the algorithm to converge, its performance with and without a receiver noise and the effect of the dither parameters are studied. The effect of element mutual coupling on the performance of the array is also demonstrated by considering an array of half-wave dipoles.