cssi/SciSciGPT-SciSciNet huggingface dataset:
Manipulatives in the History of Teaching: Fast Forward to AutOMathic Blocks for the Blind

The use of manipulative objects in the teaching of younger children has been a well know and accepted educational practice for over 200 years. The use of manipulative blocks have been valuable in the teaching of subjects such as the alphabet, linear and multidimensional measurements and early mathematics to name a few. In the current work, we present a brief overview of the traditional use of these tools as a basis for the discussion of the the AutOMathic Blocks system --- a systems that integrates the physical manipulative object with a computer to deliver personal math instruction to young students with visual impairments.
Causal Understanding in Reasoning About the World

In this paper I survey over a decade of work on how we understand how things work. Much of this work has been conducted in the context of reasoning about functions of devices. I briefly overview a representational framework called Functional Representation, and indicate how a device representation in this language can be used for simulation, diagnosis and design. I make remarks about the generality of this approach in terms of causal understanding.
Star Clusters in Merging Galaxies

Many of the most active starburst galaxies are mergers. Observations with the Hubble Space Telescope have revealed the presence of large numbers of young (typically 1 – 500 Myr), massive (103 – 107 M⊙), compact (Reff ≈ 3 pc) star clusters in merging galaxies. The brightest of these clusters have all the attributes expected of protoglobular clusters, hence allowing us to study the formation of globular clusters in the local universe rather than trying to ascertain how they formed ≈ 14 Gyr ago. Similar clusters are also found in non-merging starbursts, barred galaxies, and even normal spiral galaxies. A compilation of the literature indicates that all these systems have similar cluster luminosity functions, with the primary difference being the normalization (i.e., roughly a tenfold increase in the number of clusters in mergers). Hence, the fact that the brightest clusters are in mergers may be largely a statistical result.
Alternative non-coding exons support serotonin transporter mRNA expression in the brain and gut.

A number of studies in recent years have linked polymorphisms within the serotonin transporter (5HTT) gene to affective disorders and anxiety traits. The human 5HTT mRNA is alternatively spliced, and the splice variants are equally expressed in the human placental cell line and dorsal raphe. In this study, using 5′ rapid amplification of cDNA ends, we show that the rat 5HTT mRNA is alternatively spliced, leading to three distinct mRNAs differing in the 5′ untranslated region. To determine whether the three alternatively spliced mRNA species that contain one of the following untranslated regions (i) exon 1A, 63 bp (ii) exon 1A + 1B, 125 bp or (iii) exon 1C, 101 bp, were expressed in a tissue-specific manner, we used RT–PCR and exon-specific oligonucleotide hybridization. Our results suggest two of the variants (1A + 1B and 1A) may utilize the same promoter; however, they are not equally expressed. While in the adult CNS and adrenal medulla, the shorter mRNA consisting of exon 1A was considerably more abundant, in the stomach and heart, the two variants were equally expressed. The third splice variant exon 1C is only expressed in the gut and to a lesser extent in the heart. The data from this study suggest the splice variant consisting of exon 1C may utilize a distinct promoter compared to the other two.
When virtual is harder than real: security challenges in virtual machine based computing environments

As virtual machines become pervasive users will be able to create, modify and distribute new "machines" with unprecedented ease. This flexibility provides tremendous benefits for users. Unfortunately, it can also undermine many assumptions that today's relatively static security architectures rely on about the number of hosts in a system, their mobility, connectivity, patch cycle, etc. We examine a variety of security problems virtual computing environments give rise to. We then discuss potential directions for changing security architectures to adapt to these demands.
A modeling-free differential-inversion-based iterative control approach to simultaneous hysteresis-dynamics compensation: High-speed large-range motion tracking example

In this paper, a data-driven modeling-free differential-inversion-based iterative control (MFDIIC) method is proposed to compensate for both nonlinear hysteresis and dynamics of hysteresis-like hammerstein systems. Simultaneous hysteresis and dynamics compensation is challenging as hysteresis modeling, in many existing control methods, is rather complicated and prone to errors and uncertainties. The hysteresis and dynamics are coupled in affecting the output tracking, and both hysteresis and dynamics tend to change due to the variations of the system conditions (e.g., the age of smart actuators). The proposed MFDIIC technique aims to compensate for both of these effects with no needs for modeling hysteresis and/or dynamics, and achieve both precision tracking and good robustness against hysteresis/dynamics changes. The convergence of the MFDIIC algorithm is analyzed with random output disturbance/noise considered. It is shown that precision tracking can be achieved with the tracking error close to the noise level in the statistical sense. The proposed MFDIIC method is demonstrated through implementation on high-speed large-range output tracking of two different types of smart actuators with symmetric and asymmetric hysteresis behavior, respectively.
Carbon : nitrogen stoichiometry in forest ecosystems during stand development

Aim Carbon (C) and nitrogen (N) stoichiometry is a critical indicator of biogeochemical coupling in terrestrial ecosystems. However, our current understanding of C : N stoichiometry is mainly derived from observations across space, and little is known about its dynamics through time. Location Global secondary forests. Methods We examined temporal variations in C : N ratios and scaling relationships between N and C for various ecosystem components (i.e. plant tissue, litter, forest floor and mineral soil) using data extracted from 39 chronosequences in forest ecosystems around the world. Results The C : N ratio in plant tissue, litter, forest floor and mineral soil exhibited large variation across various sequences, with an average of 145.8 ± 9.4 (mean ± SE), 49.9 ± 3.0, 38.2 ± 3.1 and 18.5 ± 0.9, respectively. In most sequences, the plant tissue C : N ratio increased significantly with stand age, while the C : N ratio in litter, forest floor and mineral soil remained relatively constant over the age sequence. N and C scaled isometrically (i.e. the slope of the relationship between log-transformed N and C is not significantly different from 1.0) in litter, forest floor and mineral soil both within and across sequences, but not in plant tissue either within or across sequences. The C : N ratio was larger in coniferous forests than in broadleaf forests and in temperate forests than in tropical forests. In contrast, the N–C scaling slope did not reveal significant differences either between coniferous and broadleaf forests or between temperate and tropical forests. Main conclusions These results suggest that C and N become decoupled in plants but remain coupled in other ecosystem components during stand development.
Semantic scene concept learning by an autonomous agent

Scene understanding addresses the issue of "what a scene contains". Existing research on scene understanding is typically focused on classifying a scene into classes that are of the same category type. These approaches, although they solve some scene-understanding tasks successfully, in general fail to address the semantics in scene understanding. For example, how does an agent learn the concept label "red" and "ball" without being told that it is a color or a shape label in advance? To cope with this problem, we have proposed a novel research called semantic scene concept learning. Our proposed approach models the task of scene understanding as a "multi-labeling" classification problem. Each scene instance perceived by the agent may receive multiple labels coming from different concept categories, where the goal of learning is to let the agent discover the semantic meanings, i.e., the set of relevant visual features, of the scene labels received. Our preliminary experiments have shown the effectiveness of our proposed approach in solving this special intra- and inter-category mixing learning task.
Intracellular distribution of beta-actin mRNA is polarized in embryonic corneal epithelia

The intracellular distribution of filamentous actin (F-actin), all actin isoforms and beta-actin mRNA were analyzed in whole-mount preparations of freshly isolated corneal epithelia. Filamentous actin distribution was analyzed with fluorescently tagged phalloidin. An antibody that recognizes an epitope on both globular (G-actin) and F-actin was used in an immunohistochemical analysis of actin protein distribution. Whole-mount epithelial tissues were examined with a confocal laser scanning microscope (CLSM). Biotinylated oligonucleotide probes specific for the beta-actin mRNA were used, and visualized with avidin-FITC. The intracellular localization of the beta-actin mRNA was similar to the F-actin protein distribution. In the most apical optical sections of embryonic cornea, actin staining delineated the cell borders and microvilli of the periderm cells. The actin is also detected as an organized network at the interface between the basal and periderm cells. At the level of the basal cell nucleus, F-actin is sparse, associating only with the lateral cell membranes. However, at the optical plane below the nuclei, the actin forms an elaborate actin cortical mat. Actin mRNA staining was visualized as discrete punctate areas. The beta-actin mRNA was positive at the optical plane just below the periderm cell apical membrane surface, similar to actin in microvilli. These cells also contained punctate staining near the cell membranes and in the periderm-basal cell junction area. At the level of the basal cell nucleus the actin mRNA was present in a punctate pattern along the cell membranes. Below the basal cell nuclei the actin mRNA staining increased at the level of the actin cortical mat. These experiments are the first demonstration that actin mRNA is polarized in embryonic corneal epithelia and co-localized with actin protein in an intact tissue.
Illusory Diligence: Feeling Good About Doing Bad

People typically value honesty and have strong beliefs in their own morality, yet recent world events suggest that profitable mistakes are common. We suggest that one explanation for the high rate of profitable mistakes centers on the impact of irrelevant data in settings where a motive to apprehend and accurately describe the world conflicts with a motive for personal financial gain. We propose that settings that provide access to data of varying relevance afford people opportunities to endorse profitable but erroneous views while still feeling like they are honoring objectivity. Using a process-tracing platform, we demonstrate that the probability of making an error increases as people amass more evidence, but only when the mistake results in financial gain (i.e., where a conflict of interest exists; COI). Importantly, even amassed evidence with no diagnostic value licensed this impropriety. Evidence of diligence—even illusory evidence—licenses an in increase in lucrative error making.
Misexpression of the pancreatic homeodomain protein IDX-1 by the Hoxa-4 promoter associated with agenesis of the cecum

Abstract Background & Aims: The endoderm-specific homeodomain transcription factor IDX-1 is critical for pancreas development and for the regulation of islet cell–specific genes. During development, IDX-1 is expressed in the epithelial cells of the endoderm in the pancreatic anlage of the foregut. The aim of this study was to determine whether IDX-1 may have potential properties of a master homeotic determinant of pancreas and/or gut development. Methods: Transgenic mice were generated in which the expression of IDX-1 was misdirected by a promoter of the mesoderm-specific homeodomain protein Hoxa-4 known to express in the stomach and hindgut during development. The expectation was the formation of ectopic pancreatic tissue or alterations of gut patterning or morphology. Results: Although no ectopic induction of pancreatic markers was found in these transgenic mice, they manifested an altered midgut-hindgut union and agenesis of the cecum. Further, IDX-1 binds to the gut-specific homeodomain protein Cdx-2 and inhibits transactivation of the sucrase-isomaltase promoter by Cdx-2. Conclusions: These findings further support the emerging understanding that interactions among different classes of homeodomain proteins, expressed in a spatially and temporally restricted manner during development, determine the pattern of organogenesis. A possible mechanism for the dysmorphogenesis of the proximal colon may be an inhibition of Cdx-2 actions by IDX-1. GASTROENTEROLOGY 1998;115:381-387
A-C servomotor operation from unbalanced voltages

MANY analytical studies directed at the predetermination of output characteristics of a-c servomotors have been predicated on the assumptions of constant source impedance and sinusoidal excitation. Under these assumptions, the method of symmetrical components serves admirably, particularly when steady-state characteristics are desired, and in cases where the duration of the mechanical transients makes the electrical transients insignificant.
Modeling estuarine nutrient geochemistry in a simple system

We present a model of estuarine mixing, removal, and input for dissolved constituents, and apply the model to 39 nutrient (P, N, Si) profiles collected over a 14-month period in a pristine river/ estuary: Ochlockonee Bay, Florida. Each profile is deconvolved into three component functions: linear mixing (conservative) first-order removal (biological productivity), and parabolic input (regeneration). After correction for temporal variations in the fluvial end-members, the model provides quantitative estimates of total estuarine primary production, net regeneration, and subsequent fluxes to the ocean over a year-long period. The modeled data set is internally self-consistent: virtually perfect mass balances are obtained for P and Si. All biological P-uptake is regenerated within the estuary so that virtually 100% of the fluvial reactive-P enters the ocean. One-third of the fluvial reactive-P enters the estuary as particles whose phosphate is released after deposition in estuarine sediments. About 20% of the dissolved fluvial silica flux is removed biologically; all of this biogenic silica dissolves in the estuary and enters the ocean. N cannot be mass balanced, probably because it enters and escapes the bay in unmeasured forms (as NH4 or via denitrification to N2 and N2O). In the Ochlockonee, biological productivity removes nutrients in the ratios N:P ≅ 9:1 and Si:P ≅ 20:1.
The degradation of nascent fibrinogen chains is mediated by the ubiquitin proteasome pathway.

Recent studies have shown that ubiquitin-dependent proteolysis by proteasomes plays an essential role in the degradation of ER-retained proteins. We investigated the degradation of individual fibrinogen chains in transfected COS cells which express but do not secrete single chains. In transfected COS cells, the degradation of fibrinogen Bbeta and gamma chain was markedly inhibited by the proteasome inhibitors lactacystin and MG132. These specific proteasome inhibitors also partially affected the degradation of Aalpha chain. In HepG2 cells, which synthesize and secrete fibrinogen, the degradation of intracellular free gamma chain was also inhibited by MG132. We also detected high molecular weight polyubiquitinated forms of fibrinogen chains in transfected COS cells and in HepG2 cells by sequential immunoprecipitation. These results implicate proteasomes in the degradation of fibrinogen chains. In COS cells, gamma chains have a longer half-life than Bbeta chains and Aalpha chains, suggesting that the presence of surplus gamma chains in fibrinogen-producing cells is due to the unequal degradation rate of fibrinogen chains. These results indicate that the ubiquitin-proteasome pathway may be a major system for the degradation of unassembled fibrinogen chains.
A phylogeny of robber flies (Diptera: Asilidae) at the subfamilial level: molecular evidence

We present the first formal analysis of phylogenetic relationships among the Asilidae, based on four genes: 16S rDNA, 18S rDNA, 28S rDNA, and cytochrome oxidase II. Twenty-six ingroup taxa representing 11 of the 12 described subfamilies were selected to produce a phylogenetic estimate of asilid subfamilial relationships via optimization alignment, parsimony, and maximum likelihood techniques. Phylogenetic analyses support the monophyly of Asilidae with Leptogastrinae as the most basal robber fly lineage. Apocleinae + (Asilinae + Ommatiinae) is supported as monophyletic. The laphriinae-group (Laphriinae + Laphystiinae) and the dasypogoninae-group (Dasypogoninae + Stenopogoninae + Stichopogoninae + Trigonomiminae) are paraphyletic. These results suggest that current subfamilial classification only partially reflects robber fly phylogeny, indicating the need for further phylogenetic investigation of this group.
Transition Metal Polyhydride Complexes. 10. Intramolecular Hydrogen Exchange in the Octahedral Iridium(III) Dihydrogen Dihydride Complexes IrXH2(η2-H2)(PR3)2 (X = Cl, Br, I)

Density functional calculations (B3LYP) on IrXH2(η2-H2)(PR3)2 for X = Cl, Br, I and R = H, Me and inelastic neutron scattering studies for X = Cl, Br, I and R = Pri are used to elucidate the mechanisms for the intramolecular dihydrogen/hydride exchange. The two lowest energy processes are rotation of the dihydrogen ligand and oxidative addition of the dihydrogen to form an intermediate Ir(V) tetrahydride, which undergoes rapid reductive elimination to interchange the dihydrides and the dihydrogen. The use of PMe3 as a model phosphine is essential to bring the calculated barriers for the dihydrogen/hydride interchange into agreement with the experimental observations. The activation energy for site exchange (1.9 kcal/mol) is found to be in excellent agreement with the experimental result obtained for X = Cl (1.5(2) kcal/mol), and the calculations show a slight decrease in this value from X = Cl to I. Comparison between calculated rotational barriers (0.4 to 0.7 kcal/mol) and experimental values obtained fo...
Using Ensembles for Short-Range Forecasting

Numerical forecasts from a pilot program on short-range ensemble forecasting at the National Centers for Environmental Prediction are examined. The ensemble consists of 10 forecasts made using the 80-km Eta Model and 5 forecasts from the regional spectral model. Results indicate that the accuracy of the ensemble mean is comparable to that from the 29-km Meso Eta Model for both mandatory level data and the 36-h forecast cyclone position. Calculations of spread indicate that at 36 and 48 h the spread from initial conditions created using the breeding of growing modes technique is larger than the spread from initial conditions created using different analyses. However, the accuracy of the forecast cyclone position from these two initialization techniques is nearly identical. Results further indicate that using two different numerical models assists in increasing the ensemble spread significantly. There is little correlation between the spread in the ensemble members and the accuracy of the ensemble mean for the prediction of cyclone location. Since information on forecast uncertainty is needed in many applications, and is one of the reasons to use an ensemble approach, the lack of a correlation between spread and forecast uncertainty presents a challenge to the production of short-range ensemble forecasts. Even though the ensemble dispersion is not found to be an indication of forecast uncertainty, significant spread can occur within the forecasts over a relatively short time period. Examples are shown to illustrate how small uncertainties in the model initial conditions can lead to large differences in numerical forecasts from an identical numerical model.
Assessing Real-Time Tornado Information Disseminated through NWS Products

Real-timeconfirmationofatornadospecifiedin NationalWeatherService(NWS)warningsandstatements is believed to increase the credibility and urgency of these critical warning messages for the end user, because it represents the greatest degree of certainty that the hazard exists. This timely tornado information disseminated in official NWS products and relayed through multiple sources by private and public partners may help the public believe, personalize, confirm, and respond to the warning message. This is the first study to explicitly assess the frequency of real-time confirmation of ongoing tornadoes within NWS products and explore what unique conditions may facilitate or hinder this process. Tornado reports and their respective NWS warnings and statements during a 5-yr period from 2007 to 2011 across the central contiguous United Stateswerecompiledandexamined. Overall,40%oftornadoeswereconfirmedinNWSproductsinrealtime. Increasing tornado pathlength, duration, and intensity subsequently resulted in an increasing likelihood of real-time confirmation prior to the tornado dissipating. The time of day was a factor; nighttime tornadoes were 20% less likely to receive real-time confirmation than daytime events. Additionally, increasing tornado forecast risk in products issued by the Storm Prediction Center corresponded to an increasing likelihood of real-timeconfirmation.Analysisofthesedatarevealsspecificscenarioswhentornadoesaremoreorlesslikely to be reported in real time, providing some guidance for when timely ground-truth information may or may not be available.
Existence of solutions of certain systems of non-linear inequalities

In recent years there has been increasing interest in the problem of the existence of solutions to systems of linear inequalities, however little has been done in the general case of non-linear inequalities. In this paper a certain class of non-linear inequalities is considered. Several existence theorems are established which generalize certain recent results in linear inequalities.
Innovative sensor and analyses for investigating the effects of freeze-thaw on soil

Freeze-thaw is a major source of damages for infrastructures located in cold regions. Investigating the effects of freeze-thaw on soil mechanical and thermal properties is important for the design and maintenance of infrastructures such as pavements and pipelines. Most existing research investigates soil behaviors in complete freeze or complete thaw conditions. Tools to assist the determination of freeze-thaw status are currently lacking. In this paper, we introduced the design of an innovative guided electromagnetic wave sensor called Time Domain Reflectometry (TDR) that can non-destructively monitoring the freeze-thaw process in standard specimens of soil and concrete. An analysis algorithm is developed to interpret TDR signals. Compared with the existing technologies, the new method not only accurately determines the various stages in the freezing and thawing processes, but also the degree of freeze-thaw status. This analyses algorithm is also independent of soil types and thus can be widely applied. Experiments were conducted on typical types of soils to validate the sensor performance. With the aid of this new sensor, the effects of the degree of freeze-thaw on soil mechanical properties (such as the modulus, strength and volume change) are determined. The success of our preliminary study indicates the innovative sensor and analyses we developed can be a useful tool for investigating the fundamentals of freeze-thaw effects on geomaterials.
Morphology of Plasticized Polyvinylchloride

Abstract The morphology and the effect of plasticizer on the morphology of polyvinylchloride (PVC) were studied. Electron microscopy indicates that PVC contains aggregates on three size scales: 100 A to 200 A, 0.1 to0.5μ.and 1 to 10μ. The smallest of these structures are nodules which increase in size with the addition of plasticizer (DOP). This indicates that plasticizer diffuses into and disrupts the chain packing within these nodules. This has been confirmed by wide and small angle x-ray diffraction.
The geometry and internal rotational barrier of carbamic acid and several derivatives

Abstract The geometries of the following carbamate-containing molecules have been optimized at the ab initio SCF level using the MINI-1, 3-21G, and 6-31G* basis sets: carbamic acid, methylcarbamate, ethylcarbamate, N-methyl methylcarbamate, N,N-dimethyl methylcarbamate, N-vinyl methyl-carbamate and N-phenyl methylcarbamate. The latter two basis sets yield geometries in best agreement with experimental data. Calculated energy barriers for rotation about the CN bond become progressively higher as the basis set is enlarged; electron correlation leads to a modest reduction. At the MP2/6-31G*//6-31G* level, the barriers lie in the range of 80–90 kJ mol−1. Alkyl substitution on either end of the carbamate group increases the +C=O− charge separation. N-substitution reduces the electron density on the nitrogen whereas the negative charge of this atom is increased by esterification of carbamic acid.
Voltage sensor of ion channels and enzymes

Placed in the cell membrane (a two-dimensional environment), ion channels and enzymes are able to sense voltage. How these proteins are able to detect the difference in the voltage across membranes has attracted much attention, and at times, heated debate during the last few years. Sodium, Ca2+ and K+ voltage-dependent channels have a conserved positively charged transmembrane (S4) segment that moves in response to changes in membrane voltage. In voltage-dependent channels, S4 forms part of a domain that crystallizes as a well-defined structure consisting of the first four transmembrane (S1-S4) segments of the channel-forming protein, which is defined as the voltage sensor domain (VSD). The VSD is tied to a pore domain and VSD movements are allosterically coupled to the pore opening to various degrees, depending on the type of channel. How many charges are moved during channel activation, how much they move, and which are the molecular determinants that mediate the electromechanical coupling between the VSD and the pore domains are some of the questions that we discuss here. The VSD can function, however, as a bona fide proton channel itself, and, furthermore, the VSD can also be a functional part of a voltage-dependent phosphatase.
New Results for the Minimum Weight Triangulation Problem

The current best polynomial time approximation algorithm produces a triangulation that can be O(log n) times the weight of the optimal triangulation. We propose an algorithm that triangulates a set P of n points in a plane in O(n3) time and that never does worse than the greedy triangulation. We investigate issues of local optimality pertaining to known triangulation algorithms and suggest an interesting new approach to studying triangulation algorithms. We restate the minimum weight triangulation problem as a graph problem and show the NP-hardness of a closely related graph problem. Finally, we show that the constrained problem of computing the minimum weight triangulation, given a set of points in a plane and enough edges to form a triangulation, is NP-hard. These results are an advance towards a proof that the minimum weight triangulation problem is NP-hard.
A simple model of backbone flexibility improves modeling of side-chain conformational variability.

Abstract The considerable flexibility of side-chains in folded proteins is important for protein stability and function, and may have a role in mediating allosteric interactions. While sampling side-chain degrees of freedom has been an integral part of several successful computational protein design methods, the predictions of these approaches have not been directly compared to experimental measurements of side-chain motional amplitudes. In addition, protein design methods frequently keep the backbone fixed, an approximation that may substantially limit the ability to accurately model side-chain flexibility. Here, we describe a Monte Carlo approach to modeling side-chain conformational variability and validate our method against a large dataset of methyl relaxation order parameters derived from nuclear magnetic resonance (NMR) experiments (17 proteins and a total of 530 data points). We also evaluate a model of backbone flexibility based on Backrub motions, a type of conformational change frequently observed in ultra-high-resolution X-ray structures that accounts for correlated side-chain backbone movements. The fixed-backbone model performs reasonably well with an overall rmsd between computed and predicted side-chain order parameters of 0.26. Notably, including backbone flexibility leads to significant improvements in modeling side-chain order parameters for ten of the 17 proteins in the set. Greater accuracy of the flexible backbone model results from both increases and decreases in side-chain flexibility relative to the fixed-backbone model. This simple flexible-backbone model should be useful for a variety of protein design applications, including improved modeling of protein–protein interactions, design of proteins with desired flexibility or rigidity, and prediction of correlated motions within proteins.
Neuroimaging of children following prenatal drug exposure

Recent advances in MR-based brain imaging methods have provided unprecedented capabilities to visualize the brain. Application of these methods has allowed identification of brain structures and patterns of functional activation altered in offspring of mothers who used licit (e.g., alcohol and tobacco) and illicit (e.g., cocaine, methamphetamine, and marijuana) drugs during pregnancy. Here we review that literature, which though somewhat limited by the complexities of separating the specific effects of each drug from other confounding variables, points to sets of interconnected brain structures as being altered following prenatal exposure to drugs of abuse. In particular, dopamine-rich cortical (e.g., frontal cortex) and subcortical (e.g., basal ganglia) fetal brain structures show evidence of vulnerability to intrauterine drug exposure suggesting that during brain development drugs of abuse share a specific profile of developmental neurotoxicity. Such brain malformations may shed light on mechanisms underlying prenatal drug-induced brain injury, may serve as bio-markers of significant intrauterine drug exposure, and may additionally be predictors of subsequent neuro-developmental compromise. Wider clinical use of these research-based non-invasive methods will allow for improved diagnosis and allocation of therapeutic resources for affected infants, children, and young adults.
Usefulness of Retinoic Acid in the Treatment of Melasma

Melasma is a circumscribed brown macular hypermelanosis of the areas of the face and neck that are exposed to light. Clinical trials with various depigmenting formulations containing hydroquinone were conducted to determine the ideal concentration of hydroquinone, retinoic acid, and corticosteroids for the treatment of melasma. The compounds were tested with and without the concomitant use of topical sunscreen preparations. Based on the results of the trials and our earlier clinical experience, we conclude that treatment of melasma should involve the following: avoidance of sun exposure, constant use of broad-spectrum sunscreens, and topical application of a cream or lotion containing 2% hydroquinone and 0.05% to 0.1% retinoic acid (tretinoin). Patients should suspend use of oral contraceptives and other agents that promote skin pigmentation. The monobenzyl ether of hydroquinone should never be used in melasma therapy.
Spatial frequency effects of support constraints on deconvolved data

The effects of support constraints on the Fourier spectra of measured data when deconvolution is employed is evaluated using a Cramer-Rao lower bound approach. It is shown that support constraints preferentially lower the variances of the higher spatial frequencies in data corrupted by Poisson and read noises.
When orthogonal orientations are not processed independently

We studied the extent to which two gratings, superimposed at orthogonal orientations, are processed independently in making spatial frequency discriminations. Our findings suggest that independence is not preserved in this task, and that it breaks down in two distinct ways: (1) judgments about one component are reduced in accuracy by the presence of the second; and (2) information about the two component gratings is not used independently in making judgments about the compound stimulus formed by them. These results place constraints on the applicability of models that assume information from spatially tuned mechanisms is directly available in performing a discrimination task.
Switching characteristics of silicon carbide power PiN diodes

Abstract Recent progress in Silicon Carbide (SiC) material has made it feasible to build power devices with reasonable current density. This paper will present recent results including a comparison with state of the art silicon diodes. The effect of diode reverse recovery on the turn-on losses of a fast Si IGBT are studied both at room temperature and at 150°C. At room temperature, SiC diodes allow a reduction of IGBT turn on losses by as much as 6× and at 150°C junction temperature SiC diodes allow a turn-on loss reduction of between 16× and 3× when compared to fast and ultra fast silicon diodes respectively. Total losses due to reverse diode recovery were reduced by as much as 10× at 25°C and between 5× and 18× at 150°C. The yield and I – V characteristics of these diodes are also described.
An Integrated Environment for the Design and Control of Deadlock-Free Flexible Manufacturing Cells

At the enterprise level, manufacturing organizations are faced with accelerating technological cycles, global competition and an increasingly mobile work force. The flexibility of the enterprise and its ability to respond to various customer demands governs the competitiveness of the enterprise to the changes in its market and in the society in which it operates. It has been recognized for many years that flexibility on the enterprise floor can always be achieved if the resulting cost of product and process changeovers and its operations are not considered. However, with the increasing competitive pressures on today’s manufacturing enterprise, a flexible-manufacturing environment must be achieved at relatively low cost and high work-force productivity while maintaining a competitive advantage. To accomplish this goal, the manufacturing enterprise must be able to be reconfigured and verified with an increased level of automation that is scalable and flexible to meet diverse product demands quickly and economically. In this paper, we will introduce the recent research work on developing an integrated rapid prototyping environment, EMBench [22, 23], which can provide design, control configuration, simulation and deployment services for flexible manufacturing systems. This rapid prototyping environment has its own user-friendly GUI (Graphical User Interface) that allows user to issue various commands to the controller at different layers, from the simple joint servo to the complex manufacturing cell. In this paper, we also propose the implementation diagram for the controller of manufacturing cells that consists of scheduler, dispatcher, real-time database and structural control policy. All these internal components are responsible for storing system configuration, optimizing processing plan, releasing appropriate command, etc. We also present the idea of cell model and explore its characteristics and behaviors as well as the resource and workstation models. All above modules and architecture are developed using IEC-61499 function blocks that support scalable expansion and modular design. To demonstrate our theoretical achievements, we have developed various IEC-61499 function blocks to integrate various resources on the enterprise shop floor and achieve flexibility at a low cost. This software environment facilitates a modular, component-based mechanical and control design, simulating and prototyping tool for shop floor control.© 2004 ASME
Proton Charge and Adsorption of Humic Acid and Phosphate on Goethite

Little information is available about the changes of the proton charge of goethite in the presence of phosphate (P) and humic acid (HA). The objectives of this study were to systematically measure the proton charge of the ternary mixture and adsorption of HA and P on goethite. The potentiometric titration method was used to measure proton charges in single, binary, and ternary mixtures of goethite, HA, and P as a function of pH and ionic strengths. Results showed that proton charge in the ternary mixture became more negative with increasing pH and the loadings of HA and P. The point of zero charge (PZC) decreased linearly with the initial concentrations of HA and P. At low to intermediate pH, little variation was observed in adsorption of P on goethite in the presence of HA. A small reduction in the adsorption of P in the presence of HA was observed when compared with the control (without HA loading) at high pH. In 2008, Weng et al. developed a model describing the electrostatic interaction between HA and P at the 1-plane of the compact part of the electrical double layer (EDL). In this study, Weng et al.'s model was used to interpret the effect of adsorbed HA on the adsorption of P on goethite as well as the nonsignificant interaction of PZC between HA and P.
Usability and Acceptance of UF-IBA, an Image-Based Authentication System

Text-based username-password systems have been traditionally used in authenticating users before allowing them access to online services. Psychological studies have shown users' inability to recall random sequences of alpha-numeric strings, which theoretically make the best passwords. Image-based authentication (IBA) systems show great promise in circumventing users' inherent weakness. This paper provides design details of a fully functional experimental IBA system deployed at the University of Florida's CISE department, exposes issues faced by the researchers regarding user acceptance, and suggests how to make such IBA systems more usable. This paper further provides key usability insights gained from analyzing the log files of users using the system over a period of more than two semesters.
A theorem on the closure of Ω-pure subgroups of CΩ groups in the Ω-topology

The closure of ascending unions of Ω-pure subgroups of CΩ groups is discussed. Applications are given to the torsion product, the balanced-projective dimension of CΩ groups, and Kurepa's Hypothesis.
Land‐use and vegetative cover as factors influencing runoff

The estimating of intensity of runoff and of watershed-yield has long been an important problem to all engineers dealing with watershed-analyses. Many methods have been devised for making such estimates and, in California, as in other Western States, engineers are using various formula and procedures for the evaluation of these hydrologic problems.
Experimental and modeling study of chemical-kinetics mechanisms for H2–NH3–air mixtures in laminar premixed jet flames

A combined experimental and modeling study of laminar flame speeds for premixed H2–NH3–air jet flames is performed for 0–80% NH3 in H2 by energy and for equivalence ratios from 0.5 (fuel lean) to 1.1 (fuel rich). Experimental flame speeds in the jet flame configuration compare well with previous data from freely propagating spherical flames after corrections for heat losses. These data are then used to validate flame-speed predictions using CHEMKIN software over a wide range of conditions and to evaluate the performance of the GRI-Mech3.0, Tian and Konnov detailed chemical kinetic mechanisms. It is found that these mechanisms perform well for H2–air combustion but begin to deviate substantially (by ∼2×) from each other with the addition of NH3. Differences in flame speeds and associated radical species concentrations (H, O, and OH) are found to be largest for higher levels of NH3 (50% by energy and greater) and with increasing equivalence ratio. A sensitivity analysis reveals that OH is the key radical leading to NH3 decomposition and is a likely source of deviation between model predictions. The experimental data show that the Tian and Konnov mechanisms are the most capable of accurately predicting reductions in flame speed as much as 90–95% with NH3 addition, although the accuracy of each mechanism differs with the level of NH3 within the mixture.
Antigenic stability and immunodominance of the Gal/GalNAc adherence lectin of Entamoeba histolytica.

ABSTRACT Immunoprecipitation of Entamoeba histolytica proteins was performed with the sera of patients recovered from amebic liver abscess and colitis. The patients’ amebic infection had been acquired in diverse areas of the world. The amebic galactose and N-acetyl-D-galactosamine-inhibitable adherence lectin was the major amebic antigen immunoprecipitated. The adherence lectin was recognized by all of the patients’ sera tested regardless of the site (liver abscess vs. colitis) or geographic region that the amebic infection had occurred.
Contraction mappings for nonlinear boundary value problems

This paper treats mildly nonlinear boundary value problems of the form $$\begin{gathered} y'' (t) + p (t) y'(t) + f(t,y (t)) = 0 \hfill \\ y(\alpha ) = A, y(b) = B \hfill \\ \end{gathered} $$ byPicard-like methods.A priori bounds on a solution are used to generate contraction mappings on a suitable set.
Thermodynamics of formation of Y-Fe alloys

Solid electrolyte electromotive force cells have been used to determine the Gibbs free energies, enthalpies and entropies of phase formation for Y2Fe17, Y6Fe23, YFe3 and YFe2 over the temperature range 893 K to 1271 K. Solid CaF2 was employed as the electrolyte. The enthalpies of formation of the Y-Fe phases lie between −6 to −9 kJ/gm-atom. Comparison of the experimental values for the Gibbs energies of formation of the Y-Fe phases at 973 K with those of the Th-Fe, Th-Co, Th-Ni, La-Co and La-Ni systems show an empirical correlation with the total number of bonding electrons in these alloy systems.
Stabilization of RNA stacking by pseudouridine

The effect of the modified nucleoside pseudouridine (psi) on RNA structure was compared with uridine. The extent of base stacking in model RNA oligonucleotides was measured by 1H NMR, UV, and CD spectroscopy. The UV and CD results indicate that the model single-stranded oligoribonucleotides AAUA and AA psi A form stacked structures in solution and the CD results for AA psi A are consistent with a general A-form helical conformation. The AA psi A oligomer exhibits a greater degree of UV hypochromicity over the temperature range 5-55 degrees C, consistent with a better stacked, more A-form structure compared with AAUA. The extent of stacking for each nucleotide residue was inferred from the percent 3'-endo sugar conformation as indicated by the H1'-H2' NMR scalar coupling. This indirect indication of stacking was confirmed by sequential NOE experiments. NMR measurements as a function of temperature indicate that pseudouridine forms a more stable base stacking arrangement than uridine, an effect that is propagated throughout the helix to stabilize stacking of neighboring purine nucleosides. The N1-H imino proton in AA psi A exchanges slowly with solvent, suggesting a role for the extra imino proton in stabilizing the conformation of pseudouridine. These results show that the conformational stabilization is an intrinsic property of pseudouridine occurring at the nucleotide level. The characteristics of pseudouridine in these models are consistent with earlier studies on intact rRNA, indicating that pseudouridine probably performs the same stabilizing function in most structural contexts.
Learning Mixture Networks Reveal Functional Dynamics of Molecular Assemblies

While the last years have shown a steady improvement of the experimental techniques in molecular structural biology, it appears that the analysis of large macro-molecular machines relies more and more on an integrative modeling approach, by combining data from a variety of sources. Multi-resolution docking is an essential tool in this context as it not only permits a high-resolution reconstruction of molecular assemblies, but also provides tools to study the dynamics of those systems. Over the last decade, the field has developed a variety of software tools, primarily for the interpretation of volumetric data from electron microscopy.The advances in new experimental techniques leads now to an integration of a larger spectrum of data sets, for example tomographic reconstructions or small-angle scattering data. This diversity of the input data results in new challenges, including the stability of the algorithms in the presence of noise and the computational cost for a multi-resolution interpretation.A novel scoring function for hybrid modeling is introduced, relying on a feature-based description of the three-dimensional objects. The recent development of neural maps with kernel-based activation rules facilitates a reliable detection of features in arbitrary signals. These Gaussian-mixture networks are known for their accurate density estimation properties and were also used to form equi-probabilistic networks. The identical feature-extraction approach can be used for all of the different experimental techniques and the resulting point sets can be brought into registration with our efficient anchor-point matching algorithm. The performance of the new scoring measure is evaluated and the integration into a multi-resolution docking tool is discussed.This work was supported by startup funds of the University of Texas Health Science Center at Houston, by NIH grant R01GM62968, and by a grant from the Gillson Longenbaugh Foundation.
Sub-10 fs Residual Timing Jitter on a 10 GHz Optical Frequency Comb Generator

With a narrow linewidth seed laser, residual timing jitter on a 10 GHz optical frequency comb generator is reduced to 6 fs. We present analysis connecting spectral phase and laser linewidth to the timing jitter.
Influence of nanotube length on the optical and conductivity properties of thin single-wall carbon nanotube networks.

We study the optical and electrical properties of transparent conducting films made from length-sorted single-wall carbon nanotubes (SWCNT). Thin films of length-sorted SWCNTs, formed through filtr...
Drinking Levels, Related Problems and Readiness to Change in a College Sample

Abstract Drinking levels, related problems, and readiness to change alcohol use were assessed among college students (N = 179) referred to a university-based, early-intervention program. As expected, alcohol use and related problems within this sample exceeded university-wide norms, but problems were concentrated within a small sub-group who drank well above customarily defined “binge” levels. Furthermore, some individuals experienced significant problems drinking below binge levels. In general, participants showed limited acknowledgment of a drinking problem or interest in changing their behavior. Findings suggest that prevention and early intervention efforts should be based on college students' diverse drinking patterns and risk profiles, and support the argument against the dichotomous binge-drinking characterization of the problem.
A note concerning quantum mechanics and medicine

The rapid growth of quantum mechanics in the twentieth century has in no small part been due to the advanced state of classical mechanics. The introduction of new mathematical concepts to biology and medicine, on the other hand, is difficult because of the absence of a strong mathematical foundation. As a result, in many instances, new theoretical approaches to biological material have depended upon the use of mechanical and electrical analogues. As this paper shows, from a solution to a mechanical problem by means of quantum mechanics comes a potentially useful approach to a common medical problem.