cssi/SciSciGPT-SciSciNet huggingface dataset:
An examination of the relationship between answer changing, testwiseness, and examination performance

One hundred fifty college of business students participated in this study; the relationships between multiple-choice answer-changing behavior and testwiseness skills and between these 2 variables and examination performance were examined. The results indicated that answer-changing behavior was related to performance on the multiple-choice portion of examinations but not to performance on the non-multiple-choice portion of examinations or to testwiseness scores. Testwiseness scores, however, were related to performance on both the multiple-choice and non-multiple-choice portions of the examinations, indicating that overall testwiseness skills affect performance on both types of examination items. Areas for future research are also discussed.
Skin Absorption as a Route of Exposure for Aflatoxin and Trichothecenes

AbstractAirborne occurrence of mycotoxins in agricultural and residential environments has generated concern that these toxins may be absorbed via the skin and respiratory tract. This paper summarizes information available on the in vivo and in vitro cutaneous permeability of several mycotoxins (aflatoxin, T-2 toxin [T-2], diacetoxyscirpenol, and verrucarin A).Published data is used to calculate the dose absorbed during cutaneous exposure to fungal toxins in hypothetical agricultural and research laboratory environments. These estimated doses of T-2 (0.004 and 0.041 μg/kg, respectively) were 25,000 and 2,439 times less than a reported oral dose (100 μg T-2/kg/day) which caused immunosuppression in monkeys.In general, exposure of human skin to aflatoxin and trichothecenes results in slow absorption. The risk of systemic toxicity resulting from dermal exposure increases in the presence of high toxin concentrations, occlusion, and vehicles which enhance penetration.
Multiproduct production planning in the presence of work-force learning

This paper explores the multiproduct production planning problem in the presence of work-force learning (MPPL). In this setting the work-force productivity reflects a learning-curve effect which can either increase or decrease (learn or forget) as a function of previous production volume. This research advances the understanding of MPPL along a number of dimensions. We formulate MPPL as a nonlinear mixed-integer programming problem and establish problem complexity, demonstrating that it is strongly NP-hard. We also discuss some important economic properties of production planning in the presence of learning. We then define a branch-and-bound algorithm for MPPL, as well as a tabu-search heuristic (TSH). In addition, we consider a previously defined heuristic for MPPL and demonstrate that its performance can be arbitrarily bad. Computational experiments on a large set of test problems were performed to assess the performance of the algorithm and the TSH procedure, and also to study the behavior of MPPL problems. The results of the experiments indicate that despite the underlying problem complexity, the algorithm is able to solve reasonably large problems, thus providing a basis for evaluating the heuristic solution quality. The TSH consistently obtains high-quality solutions to the test problems, suggesting that the tabu-search methodology offers an effective approach to complex production planning problems. MPPL problem difficulty is seen to vary with the number of periods in the planning horizon, the relative degree of labor intensity, and the relative demand behavior of products.
“Tunable” diffusion of D2O in CO2‐swollen poly(methyl methacrylate) films

Opportunities exist to exploit the unique properties of carbon dioxide to process polymers for advanced applications. The diffusion of deuterated water in poly(methyl methacrylate) films swollen by carbon dioxide at 35°C over the pressure range 0 to 90 bar (corresponding density range: 0.0 to 0.66 g/cm3) was measured using in situ FTIR spectroscopy. The mechanism and time scale of the diffusion of deuterated water in PMMA are easily controlled by manipulation of the applied CO2 density. The enhancement of mass transport rate is consistent with the degree of plasticization of the polymer due to the absorption of carbon dioxide.
Predictors of Indoor Radon Concentrations in Pennsylvania, 1989-2013.

BackgroundRadon is the second-leading cause of lung cancer worldwide. Most indoor exposure occurs by diffusion of soil gas. Radon is also found in well water, natural gas, and ambient air. Pennsylv...
Quantum Chernoff bound metric for the XY model at finite temperature

We explore the finite-temperature phase diagram of the anisotropic XY spin chain using the quantum Chernoff bound metric on thermal states. The analysis of the metric elements allows one to easily identify, in terms of different scaling with temperature, quasiclassical and quantum-critical regions. These results extend recent ones obtained using the Bures metric and show that different information-theoretic notions of distance can carry the same sophisticated information about the phase diagram of an interacting many-body system featuring quantum-critical points.
Stability of bedforms in a tidal environment

Abstract Large-scale bedforms developed in a tide-dominated salt estuary near Sapelo Island, Georgia, are morphologically separated into two distinct groups. Megaripples include bedforms 4 to 15 m in wavelength and 10 to 75 cm in height. Sand waves are 15 to 45 m in wavelength and 85 to 130 cm in height and can be further subdivided into megarippled forms and smooth-crested forms. Ebb-oriented geometry of large-scale bedforms is maintained through both ebb and flood portions of the tidal cycle. Bedforms are in equilibrium with peak tidal flow, and ebb orientation is the direct result of large pressure gradients and related bed-shear values that develop during the ebb. Bedform heights can be statistically related to flow power, shear velocity, water depth and sediment grain size. Mean flow velocity values used in many previous studies of bedform stability did not produce significant F-statistic values in a multiple linear regression procedure used to discern relationships among variables. Stability fields of bedform types can be empirically defined using parameters statistically significant in the regression analysis. Flow power, shear velocity, water depth, and sediment grain size were used in various combinations to construct bivariate plots showing separate stability fields of sand waves and megaripples.
Retrieval of Surface Directional Reflectance Properties Using Ground Level Multiangle Measurements

Knowledge of the directional reflectance properties of natural surfaces such as soils and vegetation canopies is essential for classification studies and canopy model inversion. Atmospheric correction schemes, using various levels of approximation, are described to retrieve surface bidirectional reflectance factors (BRFs) and directional-hemispherical reftectances (albedos)from multiangle radiance measurements taken at ground level. The retrieval schemes are tested on simulated data incorporating realistic surface BRFs and atmospheric models containing aerosols. Sensitivity of the atmospherically corrected BRFs and associated directional-hemispherical reflectances to various aerosol properties and the sun-view geometry is illustrated. A measurement strategy for obtaining highly accurate surface reflectance properties also is examined in the context of instrument radiametric calibration, knowledge of the atmospheric properties, and sun-view angular coverage.
Value of the Cand-Tec Candida antigen assay in the diagnosis and therapy of systemic candidiasis in high-risk patients

A total of 911 sera from 171 patients at risk for systemic candidiasis and 24 sera from 24 non-hospitalized control subjects were analyzed for the presence of candida antigen using a commercially available latex agglutination test (Cand-Tec). Thirty-seven (22%) patients had systemic candidiasis documented by positive blood cultures, deep biopsy culture and histopathology or autopsy. Six patients had transient candidemia, 20 patients had candiduria, 53 patients had mucous membrane colonization, 21 patients were not colonized but received empiric amphotericin B, and 34 patients were not colonized and not treated with amphotericin B. The intraobserver reproducibility was 90% for the exact titer and 100% for a deviation of one dilution. The sensitivity and specificity of the candida antigen test in detection of systemic candidiasis was 95% and 50% (greater than or equal to 1:2), 73% and 72% (greater than or equal to 1:4), and 46% and 80% (greater than or equal to 1:8) respectively. Despite the poor specificity, serial antigen determinations in patients with documented systemic candidiasis demonstrated both an early diagnostic and prognostic role for the candida antigen test. Seventy-one percent of patients whose antigen titer increased during the course of amphotericin B therapy of documented infection died versus only 13% of those whose titer decreased while on therapy (p = 0.01). The candida antigen test has a limited yet potentially useful role in the diagnosis and management of systemic candidiasis in high-risk patients.
Effect on Deep Venous Thrombosis with Flexion during Total Knee Arthroplasty

This study investigates the relationship between intraoperative extreme flexion and tibia-femoral dislocation during total knee arthroplasty on the prevalence of postoperative deep venous thrombosis. Knees were randomized into two groups. The control group underwent the procedure according to normal protocol, which kept the knee in extreme flexion and maintained dislocation for the duration of the exposure, whereas the variable group underwent the procedure modified to minimize the total amount of time the knee was hyperflexed and dislocated. Venograms were positive in 42% (39/92) of the control knees and 38% (30/79) of the modified group (p = 0.6). Proximal deep venous thrombosis were found in 12% (11/92) of the control knees and in 16% (13/79) of the modified knees (p = 0.4). No statistical difference could be detected between the two techniques in regards to the incidence of deep venous thrombosis.
Effects of extracellular sodium on cytosolic calcium, PGE2 and cAMP in papillary collecting tubule cells

An increase in cytosolic calcium (Cai2+), induced by an increase in extracellular calcium concentration or addition of the calcium ionophore A23187, has been shown to suppress basal and AVP responsive cAMP and inhibit water flow in the collecting tubule. In the present study, the relationships between extracellular Na+ concentration, Cai2+, PGE2 and AVP-responsive cAMP production were examined in cultured rat papillary collecting tubule (RPCT) cells. Reducing extracellular Na+ concentration from 144 to 24 mM increased Cai2+ and PGE2 production approximately below 144 mM on Cai2+ or PGE2 was not due to a change in media osmolality or chloride concentration, since these parameters were maintained at constant levels by addition of tetramethylammonium chloride (TMA) or choline chloride. Exposure of RPCT cells to media containing 24 mM Na+ significantly suppressed basal and AVP responsive cAMP compared to that observed at 144 mM Na+. This suppression was mimicked by the calcium ionophore A23187 which also increased Cai2+ and PGE2. The increase in Cai2+ and PGE2 and the suppression of basal and AVP responsive cAMP, which were observed at 24 versus 144 mM Na+, were abolished in calcium free media and were likely due to influx of extracellular calcium. Indomethacin did not prevent the suppressive effects of reducing extracellular Na+ concentration below 144 mM on basal or AVP responsive cAMP, suggesting that the enhanced production of PGE2 did not mediate the reduction in AVP responsiveness. In contrast to cAMP, reductions in extracellular Na+ concentration from 144 to 24 mM did not influence basal cGMP or the cGMP responses to atrial natriuretic peptide or nitroprusside.(ABSTRACT TRUNCATED AT 250 WORDS)
Trisomic analysis of isozymic loci in tomato species: segregation and dosage effects.

Five isozymic loci were localized in the tomato (Lycopersicon esculentum) genome by trisomic analysis. Results revealed the following locations: Aps-1 on chromosome 6, Est-1 and Prx-2 on chromosome 2, Prx-4 on chromosome 10, and Prx-7 on chromosome 3. Three genes—Aps-1, Prx-2, and Prx-4—showed an arithmetic increase in allozyme concentration in direct proportion to the increase of gene dosage in respective primary trisomics. In contrast, no increase in relative Est-1 isozyme concentration was observed for any primary trisomic type. The phenotypes of the Aps-1, Prx-2, and Est-1 genes showed a pattern of banding intensity proportional to the allelic ratio (+/+/a vs. + /a/a) in primary trisomics; zymotypes of these differential trisomic heterozygotes appeared as “converse images” of each other.
A Mechanism for Inhibitory Effects of Diverse Compounds on in vitro Antigenic Lymphocyte Stimulation and Histamine Release From Leukocytes

Ethanol (E), nicotinamide (N), cyclic 3′, 5′ adenosine monophosphate (AMP) and theophylline (T) are examples of dissimilar compounds found to inhibit the fundamental cellular responses of antigenic histamine release and lymphocyte stimulation. As glucose is a prime source of energy and intermediates essential to cellular responses, the effects of the compounds on glucose utilization by leukocytes were determined, and corresponding inhibition of glucose metabolism was revealed. The molar concentrations required for comparable degrees of inhibition were closely similar for the two cellular responses and glucose utilization. To ascertain loci of inhibitory actions, the effects on conversion of glucose labeled with 14CO at various sites to 14CO2 were compared in suspensions of intact leukocytes and extracts of leukocytes devoid of cell membrance or nuclei. E and N were inhibitory mainly with intact cells and appear to affect glucose transport across the cell membrane. AMP and T also inhibited conversion by cell-free extracts and thus enzyme systems within the cell. Inhibition of glucose utilization by leukocytes is a common property of inhibitors of cellular responses, including E, N, Amp, T, and we found likewise for cortisol, colchicine, and chloroquine. The loci of action of the diverse compounds in the complex steps in utilization of glucose by leukocytes differ. The in vitro systems employed to compare cellular responses with glucose utilization are useful in fundamental studies and also convenient for screening of compounds for activity in these processes.
Traffic Anomaly Detection at Fine Time Scales with Bayes Nets

Traffic anomaly detection using high performance measurement systems offers the possibility of improving the speed of detection and enabling detection of important, short-lived anomalies. In this paper we investigate the problem of detecting anomalies using traffic measurements with fine-grained timestamps. We develop a new detection algorithm (called S3) that utilizes a Bayes Net to efficiently consider multiple input signals and to explicitly define what is considered "anomalous''. The input signals considered by S3 are traffic volumes and correlations between ingress/egress packet and bit rates. These complementary signals enable identification of an expanded range of anomalies. Using a set of high precision traffic measurements collected at our campus border router over a 10 month period and an annotated anomaly log supplied by our network operators, we show that S3 is highly accurate, identifying 86% of the anomalies listed in the log. Compared with well known time series-based and wavelet-based detectors, this represents over a 20% improvement inaccuracy. Investigation of events identified by S3 that did not appear in the operator log indicate many are, in fact, true positives. Deployment of S3 in an operational environment supports this by showing zero false positives during initial tests.
Hydrodynamic heat flow in very dilute superfluid3He-4He mixtures

The superfluid hydrodynamics of heat flow is examined for very small mass concentrations c of /sup 3/He in /sup 4/He in an effort to better understand recet results for the effective heat conductivity kappa/sub eff/, which appear to be in conflict with predictions. The full hydrodynamics contains a thermal boundary layer; within this layer the temperature and concentration gradients differ from those in the bulk fluid. An examination of finite heating effects based on the ansatz kappa/sub eff/proportionalc/sup -//sup p/ for small c shows distinctly different behavior for experimental determinations of kappa/sub eff/ when p 1. Thus, finite heating can be used as a probe to evaluate the exponent p.
Evaluation of some DNA cloning strategies

Abstract By considering a DNA molecule as a random sequence of four letters, a mathematical model of two important steps in DNA cloning processes is described: degradation of large DNA molecules using restriction enzymes, and replication of the resulting DNA fragments by viral vectors. The model is used to evaluate the feasibility of obtaining target gene loci using a large number of restriction enzymes, and to estimate the fraction of genomic DNA that is clonable.
Changing Focus of Textiles and Clothing Within Home Economics: An Analysis of Two Professional Journals

The visibility of textiles and clothing within home economics was measured by the number of articles published in the Journal of Home Economics from 1911 through 1980 and the Home Economics Researc...
Suggested Inferential Statistical Models for Research in Behavior Modification.

Operant Conditioning procedures have diffused to applied educational settings where results are not descriptively obvious. Inferential statistics using Multiple Linear Regression Analysis (MLR) to partial variance to answer specific behavioral modification research questions are presented. Four applications of MLR to typical behavioral modification designs are illustrated. The examples represent the case where the research questions dictate the statistical design. Assumptions regarding individual subject design and repeated measurement problems are presented and are seen as minor sources of difficulty for use of inferential statistics in behavioral modification studies.
Anticipatory pleasure predicts motivation for reward in major depression.

Anhedonia, the lack of interest or pleasure in response to hedonic stimuli or experiences, is a cardinal symptom of depression. This deficit in hedonic processing has been posited to influence depressed individuals’ motivation to engage in potentially rewarding experiences. Accumulating evidence indicates that hedonic processing is not a unitary construct but rather consists of an anticipatory and a consummatory phase. We examined how these components of hedonic processing influence motivation to obtain reward in participants diagnosed with major depression and in never-disordered controls. Thirty-eight currently depressed and 30 never-disordered control participants rated their liking of humorous and nonhumorous cartoons and then made a series of choices between viewing a cartoon from either group. Each choice was associated with a specified amount of effort participants would have to exert before viewing the chosen cartoon. Although depressed and control participants did not differ in their consummatory liking of the rewards, levels of reward liking predicted motivation to expend effort for the rewards only in the control participants; in the depressed participants, liking and motivation were dissociated. In the depressed group, levels of anticipatory anhedonia predicted motivation to exert effort for the rewards. These findings support the formulation that anhedonia is not a unitary construct and suggest that, for depressed individuals, deficits in motivation for reward are driven primarily by low anticipatory pleasure and not by decreased consummatory liking.
Relationships between speech intelligibility and word articulation scores in children with hearing loss.

Purpose This investigation sought to determine whether scores from a commonly used word-based articulation test are closely associated with speech intelligibility in children with hearing loss. If ...
The photochemistry of methane and carbon monoxide in the troposphere in 1950 and 1985

The roughly 1 percent/year increase in tropospheric methane and roughly 2 percent/year increase in tropospheric carbon monoxide deduced from recent analyses of ground-based solar infrared spectra recorded in 1950 and 1951 have very important implications for the photochemistry and chemistry of the troposphere. Photochemical calculations indicate that as a result of the increase of methane and carbon monoxide since 1950-51, levels of the hydroxyl radical, the key species in the photochemistry of the troposphere, may have decreased by about 25 percent.
A generalized bio-inspired method for discovering sequence-based signatures

Many phenomena that we wish to discover are comprised of sequences of events or event primitives. Often signatures are constructed to identify such phenomena using either distributions or frequencies of attributes, or specific subsequences that are known to correlate to the phenomena. Distribution-based identification does not capture the essence of the sequence of behaviors and therefore may suffer from lack of specificity. At the other extreme, using specific subsequences to identify target phenomena is often too specific and suffers from lower sensitivity when natural variations arise in the phenomena, measuring process, or data analysis. We introduce here a method for discovering signatures for phenomena that are well characterized by sequences of event primitives. In this paper, we describe the steps taken and lessons learned in generalizing a sequence analysis method, BLAST, for use on non-biological datasets including expressing and operating on alphabets of varying length, constructing a reward/penalty model for arbitrary datasets, and discovering low complexity segments in sequence data by extending BLAST's native low-complexity estimating algorithms. We also present high-level overviews of several case studies that demonstrate the utility of this method to discovering signatures in a wide array of applications including network traffic, software analysis, server characterization, and others. Finally, we demonstrate how signatures discovered using this method can be expressed using a variety of model formalisms, each having its own relative benefit.
THE POPULATION MECHANISM IN W. S. JEVONS'S APPLIED ECONOMICS*

The status of the population principle in the work of the nineteenth-century economist W. S. Jevons is examined. "A careful reading of Jevonss writings reveals that population growth was not treated as an exogenous variable in the context of growth and poverty issues. The key to his position concerning the population mechanism is the contention--in line with Marshall and the classics--that population growth is a major determinant of economic welfare the extent and severity of pauperism being linked to population relative to labour demand growth rates." (EXCERPT)
Motivating long‐term employment contracts: risk management in major league baseball

Long-term employment contracts have typically been modeled as mechanisms whereby workers reduce the risk of lost income with a guaranteed long-term wage that is less than the expected spot wage. Examination of contract length among major league baseball players shows that long-term contracts for marginal players, those for whom it would seem most logical to desire this insurance, are rarely observed. Star players, whose income levels should enable them to purchase this sort of insurance from other sources, represent the majority of long-term contract holders. This paper presents a theoretical model showing that firms, when facing both market uncertainty and uncertainty about an employee's future productivity, have an incentive to reallocate risk with long-term labor contracts. In such cases, a long-term contract may be observed without a risk premium paid by the worker. The labor markets of professional sports represent this combination of market and productive uncertainty. Empirical results from major league baseball using a binary choice probit model, which corrects for sample selection bias, support the hypothesis that factors, which increase market uncertainty and reduce productive uncertainty, are consistent with the observation of long-term contracts. Copyright © 2004 John Wiley & Sons, Ltd.
Modulation of zymosan stimulated leukotriene release by dietary unsaturated fatty acids.

Abstract The quantity of leukotrienes produced in an inflammation model, the stimulated mouse peritoneum, was affected by dietary manipulation of tissue arachidonic acid, the immediate leukotriene (LT) precursor. Fifty ng of LTE4 was synthesized (after injection of zymosan) by the peritoneal cavity of mice maintained on olive oil as a dietary source of unsaturated fatty acids . Animals maintained on corn oil, exhibited significantly enhanced leukotriene biosynthesis upon stimulation by zymosan. Mice fed menhaden oil, a fat source rich in n-3 fatty acids produced 50% less leukotriene E4 than animals fed olive oil. The results indicated that production of leukotrienes, potent mediators of inflammatory reactions,are affected by the type of polyunsaturated fatty acids in the diet.
Seasonal cycles in radium and barium within a subterranean estuary: Implications for groundwater derived chemical fluxes to surface waters

Abstract There is increasing evidence that submarine groundwater discharge (SGD) is an important source of water and dissolved materials to the ocean. One of the primary tracers of this process is the quartet of radium isotopes ( 223 Ra, 224 Ra, 226 Ra and 228 Ra), whereby excess activities in surface waters can often be attributed to an input supplied via SGD. This approach requires the radium end member activity to be well constrained, however, natural variability in groundwater radium may span several orders of magnitude. Therefore, this variability is usually the main driver of uncertainties in volumetric SGD estimates. To investigate the physical and biogeochemical controls on groundwater radium activities, we conducted a three-year time series of radium and barium, a chemical analogue for radium, within the subterranean estuary of a coastal aquifer (Waquoit Bay, MA, USA). Gonneea et al. (2013) demonstrated that movement of the salinity interface within the subterranean estuary is driven by changes in the hydraulic gradient between groundwater level and sea level height. For Waquoit Bay, seasonal scale sea level change, not groundwater level, was the main driver in hydraulic gradient fluctuations. Seasonal changes in groundwater chemistry can be attributed to the resulting movement of the salinity transition zone between terrestrial and marine groundwater. Landward movement of the interface results in a large release of radium isotopes ( 226 Ra = 1400 dpm 100 L −1 ) and barium (3000 nmol kg −1 ) associated with an increase in groundwater salinity. The magnitude of these releases cannot be explained by in situ production or weathering alone, but is likely due to salinity driven desorption from surface-bound sediment inventory. The timing of these peak concentrations is not always in phase with model-derived estimates of SGD; as a result, the groundwater concentration rather than the water flux is the main driver of Ra and Ba inputs to Waquoit Bay surface waters. The behavior of the subterranean estuary as an ion exchange reservoir has important implications for the timing and flux of various nutrients and pollutants that transit this region prior to discharge. In addition to modulating chemical fluxes via submarine groundwater discharge on seasonal time scales, transgression of the subterranean estuary may alter the input of chemicals to the ocean on decadal and longer time scales. During this study, the observed excess flux of 226 Ra and Ba from the subterranean estuary can be accounted for with sorbed sediment pools and accelerating rates of sea level rise in this region.
A single pair of interneurons controls motor neuron activity during pre-ecdysis compression behavior in larval Manduca sexta

Manduca sexta molts several times as a larva (caterpillar) before becoming a pupa and then an adult moth. Each molt culminates in ecdysis behavior, during which the old cuticle is shed. Prior to each larval ecdysis, the old cuticle is loosened by pre-ecdysis behavior, which includes rhythmic, synchronous compressions of the abdomen. A previous study indicated that motor neuron activity during pre-ecdysis compression behavior is driven by an ascending neural pathway from the terminal abdominal ganglion. The present study describes a pair of interneurons, designated IN-402, that are located in the terminal ganglion and belong to the ascending pathway. Each IN-402 is synchronously active with pre-ecdysis compression motor bursts, and bilaterally excites compression motor neurons throughout the abdominal nerve cord via apparently monosynaptic connections. The pair of IN-402s appears to be the sole source of rhythmic synaptic drive to the motor neurons during the pre-ecdysis compression motor pattern. These interneurons play a key role in the production of larval pre-ecdysis behavior, and are candidates for contributing to the developmental weakening of pre-ecdysis behavior at pupation.
The Effects of Central Injections of Calcitonin Gene-Related Peptide on Fear-Related Behavior

Calcitonin gene-related peptide (CGRP) has been localized in several regions of the rat brain that are known to be important for the expression of fear responses. Some evidence suggests that CGRP may act as a neurotransmitter at synapses that are believed to be important for aversive learning. In the present study, male rats were prepared with intracerebroventricular cannulae and injected with CGRP during different phases of training and testing when a distinctive environment was paired with foot shock. When injected prior to training, CGRP directly evoked fear-related behavior and postshock freezing. When pretreated with CGRP and exposed to the shock-associated environment 24 h after training rats again showed an enhanced fear response. These results support the idea that this peptide functions as a neurotransmitter at central synapses which are important for the expression of fear.
IMPROVED ALLELIC EXCHANGE VECTORS AND THEIR USE TO ANALYZE 987P FIMBRIA GENE EXPRESSION

A series of vectors has been developed to provide improved positive and negative selection for allelic exchange. Based on homologous regions of DNA ranging in size from less than 200 bp to over 1 kb, we have successfully used these new plasmids to introduce or remove markers in chromosomal or plasmid DNA. Wild type fimbria genes were replaced both in Salmonella enteritidis (sefA, agfA and fimC) and Escherichia coli (fasA and fasH). Regulation of 987P fimbriation could be identified after replacement of fasA and fasH with allelic reporter fusions. The expression of fasA but not fasH is dependent upon the osmolarity of the growth medium in an HNS-dependent manner, but unlike some other fimbrial systems expression is not dependent on the exogenous iron concentration.
Aging's Effect on Physical Performance and Single Muscle Fiber Contractility in a Nonhuman Primate Model

Previous studies on the intrinsic contractile properties of human myofibrils reported increase, decrease, or no change with aging, perhaps due to differences in physical activity, diet, and other factors. We examined myofilaments' contractile characteristics and physical performance, walking speed and climbing rate, in African green vervet monkeys, housed in social groups in large indoor-outdoor enclosures and fed the same diet. Physical performance and skinned vastus lateralis (VL) muscle fiber function were investigated in four young (11±1 yrs) and four old (23±1 yrs) monkeys. Fiber myosin heavy chain (MHC) isoform was determined by gel electrophoresis. The old monkeys walked slower (19%) and climbed less (63%) than young monkeys (p<0.05). Myofiber cross sectional area (CSA) was 22% and 12% smaller for IIa and hybrid MHC, respectively, in old compared to young monkeys (p<0.001). Specific force (maximal Ca2+-activated force normalized to fiber CSA) was 15% and 11% less for type IIa and hybrid fiber, respectively, in old compared to young monkeys (p<0.05). Fiber atrophy does not account for the loss in force with aging; it declined much faster than fiber CSA. Although we observed no difference in shortening velocity, the maximal power output substantially decreased in 21% of type IIa and 22% of hybrid fibers with aging (p<0.05). Regression modeling used to identify factors contributing to lower fiber force revealed that age is the strongest predictor (r2=0.31, p<0.001). The diminished contractile properties measured in vitro correlates strongly with age-dependent decline in physical performance (waking speed: r = 0.41, p < 0.001); climbing rate: r = 0.29, p < 0.001). Our results support a detrimental effect of aging on the innate force and power generation of myofilament lattice and physical performance.
Cellular functions of metallo-endoproteinases

I1. Regulation of metallo-endoproteinase activity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150 A Transcriptional regulation of metalio-endoproteinases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 B Secretion and activation of proproteinase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 C Natural inhibitors of metallo-endoproteinases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 D Synthetic inhibitors of metallo-endoproteinases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
Onset of f-bonding in light actinide and lanthanide metals at ultrahigh pressures

Abstract The onset of f-bonding as a result of electron transfer under pressure has been investigated experimentally by interpreting structural distortions which accompany this phenomenon in light actinide and lanthanide metals. Structural studies were carried out on the light actinide metal, thorium (Th), below 100 GPa and also in the ultrahigh pressure regime to 300 GPa by energy dispersive X-ray diffraction techniques using synchrotron radiation sources. Based on the forward and reverse transformation data, the FCC to BCT equilibrium pressure for Th has been determined to be 60 ± 4 GPa at 300 K. Detailed comparisons are made between the phase transformations of Th and those of the light lanthanide metal, cerium (Ce). The intermediate body centered monoclinic phase, reported to exist between the FCC and the BCC phases in Ce, was not observed for Th. The possible scaling relations between the phase diagrams of Ce and Th are discussed.
Platinum Participation in the Hydrogenation of Phenylacetylene by Ru5(CO)15(C)[Pt(PBut3)]

The hydride and PhC2H complexes, Ru5(CO)14(μ6-C)[Pt(PBut3)](μ-H)2, 2, and Ru5(CO)13(μ5-C)(PhC2H)[Pt(PBut3)], 3, were obtained from the reactions of Ru5(CO)15(C)[Pt(PBut3)], 1, with hydrogen and PhC2H, respectively. Styrene was formed catalytically when hydrogen and PhC2H were allowed to react with 3 in combination, and the complex Ru5(CO)12(μ5-C)[PtPBut3](PhC2H)(μ-H)2, 4, containing both hydrides and a PhC2H ligand was formed. The catalysis is promoted by the presence of the platinum atom in the complexes.
An Epilepsy-Associated Mutation Enhances BK Channel Activity by Altering the Coupling of Calcium Sensing to Gate Activation

Voltage and Ca2+ activated BK channels modulate neuronal activities. Previous studies found that Ca2+ binding sites and the activation gate are spatially separated, but how Ca2+ binding couples to gate opening is not clear. We address this question by studying how a mutation in BK channels, which is associated with generalized epilepsy and paroxysmal dyskinesia (D434G in hSlo, the epilepsy mutation), enhances Ca2+ sensitivity. The epilepsy mutation is located in a structural domain (the AC region) that connects the S6 transmembrane segment with the cytoplasmic domain and close to a putative Ca2+ binding site. Mutagenesis studies show that the AC region is important in the coupling between Ca2+ binding and gate opening. We found that discrete locations in the AC region that are distant from the epilepsy mutation alter the functional effects of the mutation. Thus, the epilepsy mutation enhances Ca2+ sensitivity by an allosteric mechanism affecting the coupling between Ca2+ binding and gate opening. Interestingly, mutating the Asp residue to amino acids other than Gly does not result in the same phenotype as the epilepsy mutation, suggesting that a change in protein flexibility is involved in the effects of the mutation. Consistent with this result, altering the flexibility of the channel protein by changing viscosity of the intracellular solution also modulates Ca2+ sensitivity; and the epilepsy mutation reduces such modulation, possibly because it has already altered the flexibility. These results are consistent with a model that the peptide loop where the putative Ca2+ binding site and the epilepsy mutation are located acts as a spring-hinge for the conformational change of the AC region during channel opening; Ca2+ binding and the epilepsy mutation affect channel gating by altering the function of this spring-hinge.
Propagation of spherical combustion waves

Abstract Properties of spherical detonation waves of various fueloxidizer gas mixtures have been determined. The detonations were produced in 65 cm diameter thin walled rubber balloons; gases were initially at room temperature and atmospheric pressure. Experimental data were recorded with a high-speed strip film camera. Results showed that: (1) the propagation rates of stabilized spherical detonation waves of all systems studied are similar to those measured in long tubes, (2) the induction distances of acetyleneoxygen mixtures are inversely related to the ignition energy, and (3) the combustion waves were initially overdriven regardless of the method of ignition.
Assessing the performance of sampling designs for measuring the abundance of understory plants

Accurate estimation of responses of understory plants to disturbance is essential for understanding the efficacy of management activities. However, the ability to assess changes in the abundance of plants may be hampered by inappropriate sampling methodologies. Conventional methods for sampling understory plants may be precise for common species but may fail to adequately characterize abundance of less common species. We tested conventional (modified Whittaker plots and Daubenmire and point–line intercept transects) and novel (strip adaptive cluster sampling [SACS]) approaches to sampling understory plants to determine their efficacy for quantifying abundance on control and thinned-and-burned treatment units in Pinus ponderosa forests in western Montana, USA. For species grouped by growth-form and for common species, all three conventional designs were capable of estimating cover with a 50% relative margin of error with reasonable sample sizes (3–36 replicates for growth-form groups; 8–14 replicates for c...
Design and fabrication strategies for high transparency polymer nanocomposites with dynamic tunable optical response

Optical sensors that are applied in conjunction with bright optical sources such as lasers typically have to be protected from damaging light exposure levels by the use of optical limiters. The principal aims for optical limiter materials are: (1) to block selectively the frequency of interest at high light levels and – at low light levels – exhibit high transmittance of optical frequencies in order to enable the fabrication of transparent yet protective windows; (2) a rapid response time when exposed to high light levels. Novel opportunities for the design of materials with dynamic switchable limiting properties are provided by optically transparent two-photon active polymer nanocomposites materials in which the scattering strength of embedded particle fillers can be dynamically modulated by the nonlinear absorption of a polymer host medium. In a first part this contribution will present recent results on the synthesis of silica nanoparticles that are index-matched to organic solvents by means of polymer functionalization. Effective medium theory will be shown to provide a valuable tool in predicting polymer-graft compositions that are index-matched to the embedding solvent thus resulting in dramatically reduced linear scattering cross section of the particle dispersant. The second part of this contribution will present preliminary results on the linear and nonlinear optical properties of particle dispersions in both solvent and solutions of two-photon active (TPA) dyes. For mixed solutions of TPA-dyes and index-matched particle fillers an increased limiting efficiency is observed while neat particles are found to be TPA inactive.
Doing Economics: Enhancing Skills through a Process-Oriented Senior Research Course.

The author describes a senior-level course designed to promote student skills in "acting like economists." Although most departments offer senior-level courses, this one is unique in that it was developed on the basis of learning as opposed to content objectives, assignments are designed to reinforce and further develop research skills through a project of the student's choosing, and it more closely models what it means to "act like an economist" (W. L. Hansen 2006). The author discusses the development of this course and its unique features, the research process followed by students and the outcomes generated, and some of the advantages and disadvantages associated with this form of senior research course.
Malignancy validation in a United States registry of rheumatoid arthritis patients

Background: Physician reporting is commonly used to ascertain adverse events or outcomes measured in epidemiologic studies. However, little is known on the accuracy of physician reported malignancies compared to pertinent medical record review in large cohort studies. Methods: The Consortium of Rheumatology Researchers of North America (CORRONA) registry gathers physiciancompleted questionnaires for rheumatoid arthritis (RA) patients, including request for information on incident malignancies, approximately every three months. For incident malignancies reported from October 1st, 2001, through December 31st, 2007, we retrospectively requested completion of a Targeted Adverse Event (TAE) form for additional information as well as primary source documents to adjudicate the malignancy reports. CORRONA has employed a prospective request for source documentation for these events since 2008. We classified each malignancy as definite, probable, possible, or not a malignancy. Results: From 20,837 RA patients enrolled in CORRONA, 461 incident malignancies were initially reported on physician questionnaires. After review of returned source documents with adjudication, 234 were deemed definite, 69 probable, 101 possible, and 57 not an incident malignancy. The positive predictive value (PPV) of initial physician report of a malignancy versus “definite or probable” malignancy based on adjudication was 0.66 (95% CI 0.61 - 0.70). The PPV was 0.68 (95% CI 0.63 – 0.72) when the subsequent TAE form also confirmed the presence of malignancy. When possible malignancies were included, the PPV of physician-reported malignancies without a subsequent TAE form increased to 0.86 (0.83 – 0.89), and with a subsequent TAE form, 0.89 (0.85-0.91). Conclusion: Twelve percent of initial physician reports of incident malignancy could not be confirmed with review of source documents. The most common reason for lack of confirmation was inability to obtain documents or insufficient data in source materials. These results suggest that timely collection of relevant medical records and an adjudication process are required to improve the accuracy of cancer reporting in epidemiologic studies.
Alteration of EGF-receptor binding in human breast cancer cells by antineoplastic agents

Abstract Polypeptide growth factors bind to membrane receptors on human breast cancer cells and stimulate cell proliferation, suggesting that they may be important in growth regulation. Inhibition of the stimulatory effects of these factors might result in antineoplastic activity. Since cytotoxic drugs have been shown to alter cell membrane characteristics, we have examined the effects of a variety of antitumor drugs on the binding of epidermal growth factor (EGF) to the membrane receptor of human breast cancer cells. Twenty-four standard or investigational cytotoxic drugs were screened at a concentration of one-tenth the achievable peak plasma level for their ability to inhibit binding of 125 I -EGF to its receptor in MCF- 7 human breast cancer cells. Although at this concentration statistically significant inhibition of binding was observed with 11 drugs, the maximum inhibition observed was only 27% . Five agents, representing classes of drugs with different modes of action, were then studied in more detail. Of these, preincubation with 5 -fluorouracil, 4 -hydroperoxy-cyclophosphamide and doxorubicin inhibited MCF- 7 colony formation in a dose-dependent manner, but these drugs had no effect on EGF-binding even at a concentration of 10 times the peak plasma level. Preincubation of cells with vinblastine and cisplatin, however, resulted in both reduced colony survival and a parallel reduction in EGF receptor binding. Membrane integrity, as measured by trypan blue exclusion, was not altered. Scatchard analysis of EGF binding demonstrated that the major effect of cisplain was a reduction in binding affinity. We conclude that cisplatin and vinblastine at high concentrations can inhibit the binding of EGF to human breast cancer cells offering an additional possible mechanism for their antiproliferative activity.
Enhanced electrochemiluminescence from Os(phen)2 (dppene)2+ (phen = 1,10-phenanthroline and dppene = bis (diphenylphosphino)ethene) in the presence of Triton X-100 (polyethylene glycol tert-octylphenyl ether)

The effects of the non-ionic surfactant Triton X-100 (polyethylene glycol tert-octylphenyl ether) on the properties of Os(phen)2(dppene)2+ (phen=1,10-phenanthroline and dppene=bis(diphenylphosphino)ethene) electrochemiluminescence (ECL) have been investigated. The anodic oxidation of Os(phen)2(dppene)2+ produces ECL in the presence of tri-n-propylamine (TPrA) in aqueous surfactant solution. Increases in ECL efficiency (≥3-fold) and TPrA oxidation current (≥2.0-fold) have been observed in surfactant media with experiments supporting adsorption of surfactant on the electrode surface.
Construct validity of a competitive reaction‐time aggression paradigm

This study tested the construct validity (convergent and discriminant) of a competitive reaction-time aggression paradigm. Seventy-nine males completed three trait aggression questionnaires and then competed on a reaction-time task whereby they received and delivered shocks to a fictitious opponent. Results demonstrated strong positive relationships between shock intensity administered and the trait measures of overt aggression but not with the measures unrelated to overt aggression. Results are discussed with regard to their contribution to the construct validity of the aggression paradigm used in this study.