cssi/SciSciGPT-SciSciNet huggingface dataset:
Performance of concrete beams prestressed with aramid fiber-reinforced polymer tendons

Abstract Deterioration related to steel corrosion of constructed facilities such as bridge decks and large structures has resulted in costly repairs and led to users' inconvenience. To increase the longevity of these facilities, an intelligent use of materials and new designs will be essential. There is an increasing worldwide interest in utilizing fiber-reinforced polymer (FRP) composites for civil infrastructure applications. This paper presents the results of an experimental study on the flexural behavior of concrete beams prestressed with aramid fiber-reinforced polymer (AFRP) tendons. Concrete beams prestressed with FRP tendons usually exhibit brittle failure due to the brittle nature of the FRP composites. In order to improve the ductility of such beams, a series of flexural tests was conducted on four full-scale beams prestressed with bonded and/or unbonded aramid rectangular tendons. Results show that ductility can be significantly enhanced by using a combination of bonded and unbonded tendons or by the addition of nontensioned rebars.
Parkfield's unfulfilled promise

The idea that earthquakes are 'time-predictable' underlies many of today's probabilistic forecasts. In a key test on California's San Andreas fault the concept is found wanting, but the news may not be all bad.
Iterative adaptive RBF methods for detection of edges in two-dimensional functions

Radial basis functions have gained popularity for many applications including numerical solution of partial differential equations, image processing, and machine learning. For these applications it is useful to have an algorithm which detects edges or sharp gradients and is based on the underlying basis functions. In our previous research, we proposed an iterative adaptive multiquadric radial basis function method for the detection of local jump discontinuities in one-dimensional problems. The iterative edge detection method is based on the observation that the absolute values of the expansion coefficients of multiquadric radial basis function approximation grow exponentially in the presence of a local jump discontinuity with fixed shape parameters but grow only linearly with vanishing shape parameters. The different growth rate allows us to accurately detect edges in the radial basis function approximation. In this work, we extend the one-dimensional iterative edge detection method to two-dimensional problems. We consider two approaches: the dimension-by-dimension technique and the global extension approach. In both cases, we use a rescaling method to avoid ill-conditioning of the interpolation matrix. The global extension approach is less efficient than the dimension-by-dimension approach, but is applicable to truly scattered two-dimensional points, whereas the dimension-by-dimension approach requires tensor product grids. Numerical examples using both approaches demonstrate that the two-dimensional iterative adaptive radial basis function method yields accurate results.
Sex, Sex Differences, and Social Behavior

Sex differences in social behavior are center stage in recent formulations of evolutionary psychology. Evolutionary psychology, with its emphasis on the long-term consequences of early adaptations, offers itself as an alternative meta-theory to mainstream social psychology, which emphasizes the importance of social structures in determining the existence and extent of social and cognitive sex differences. Using a range of examples, we argue that evolutionary psychology is open to criticism on several fronts: It does not (a) include a role for mediating and moderating variables or test predictions rigorously; (b) appreciate the importance of the difference between first- and second-order effects; (c) offer a truly interactionist theory; or (d) seriously consider the social implications of sex-based inequities. We also argue that social psychology has, in its turn, failed to appreciate the non-intuitive richness of some evolutionary hypotheses or that there is a role for evolutionary psychology in a genuinely interactionist theory This paper restates the need for that perspective, and suggests how it may be achieved.
In-Plant Evaluation of Dense Medium Process Performances

The separation density and process efficiency values achieved by dense medium processes are a function of the particle size fractions being treated, hydrodynamics of the separator, and medium rheology. An in-plant evaluation of the dense medium processes being used in an operating preparation plant was conducted in an effort to develop relationships between the actual separation density and the medium density and to quantify the separation efficiency values. The results were found to correlate well with current fundamental and operating principles governing the processes, which are reviewed and discussed.
Fast Encryption Method Based on New FFT Representation for the Multimedia Data System Security

In this paper, we have presented a new fast Fourier transform representation based cryptographic (encryption) system for the multimedia data security. The key features of the proposed system are: 1. Mapping/representation of the fast Fourier transforms' structure based on discrete orthogonal transforms, such as Walsh-Hadamard, Haar, and complex Walsh-Hadamard, etc. 2. The efficient implementations of the encryption within the core of the fast Fourier transform (flexibility in the shuffling of the sensitive information). In addition to these key features, the computational complexity of the system is comparable with commonly used methods. One of the important differences between the existing transform based encryption systems, and the proposed is that the encryption has been done in the core of the transform, which ultimately provides the highest level of security to the sensitive data. The proposed system consequently has the dual key security feature, which consists of the encryption and the transform dependent keys.
Evidence for a carbonate species during CO oxidation on deactivated Rh(111)

Abstract In earlier work from this laboratory on the oxidation of CO over a single-crystal Rh(111) model catalyst, it was found that the kinetics of the reaction change dramatically when the reaction conditions were varied from reducing to oxidizing. These earlier studies suggested the possibility that the observed changes in reaction kinetics arose from the formation of a surface carbonate species, i.e., RhO(CO2), on oxidized Rh which alters the kinetics and decreases the reaction rate because of the tenacious bonding of this complex. In order to further investigate this suggestion, we have recently performed a high-resolution electron energy loss, HREELS (surface vibrational spectroscopy), study of the intermediate species present on the Rh surface under various reaction conditions in conjunction with temperature-programmed desorption (TPD) measurements. The results provide further evidence that such a carbonate complex is present on the surface after reaction under oxidizing conditions. However, we also observed that under these conditions the surface is hydroxylated, probably arising from the presence of impurity H2O or H2 in the reactor. TPD results confirm the importance of these -OH groups in stabilizing the carbonate complex. For example, CO2 adsorbed on a “clean” oxide (prepared by high temperature oxygen exposures in ultrahigh vacuum) was found to desorb at temperatures more than 100°C lower than CO2 desorption from a hydroxylated Rh-oxide surface. In the latter case, CO2 desorption likely arises from the reaction-limited decomposition of the carbonate species. In fact, the earlier kinetic studies are most consistent with an overall reaction mechanism for CO oxidation under oxidizing conditions involving the rate-limited decomposition of such a surface-bound carbonate species.
Regressive periods in primate behavioral development with reference to other mammals

Studies on behavioral development in 12 species of monkeys indicate normal fluctuations of high frequency of nipple contact. These periods decrease in intensity as the infant develops and occur at similar times in development in the 12 species. Literature on 11 species of primates and three species of non-primates indicates similar regressions in mother-infant contact, which implies a common genetic basis for the phenomenon.
Weak seams: Controversy over welding theory and practice in american shipyards, 1938-1946

At the height of World War II, America's record-setting shipyards were stunned when several merchant ships literally cracked in half. Worried that endemic manufacturing defects might endanger the entire wartime merchant marine, engineers argued that poor workmanship by shipyard welders had contributed to the accidents, that their own technical expertise should be more highly valued, and that they should be granted greater authority over the shipyard workforces. However, administrators in US Maritime Commission rejected these arguments. Instead, federal officials and shipyard managers assumed that many factors had contributed to the fractures and chose to implement a few modest, practical measures which soon stopped the fracture epidemic: improved worker training, the elimination through redesign of certain structural flaws in the endangered ships' hulls, and especially the installation of reinforcing devices at weak points in the ships. This episode not only draws attention to the way warfare heightens th...
Compulsive weight lifting and anabolic drug abuse among women rape victims

In the course of a study of 75 female weight lifters, we encountered 10 (13%) who reported that they were raped as teenagers or adults. Nine of these women began or greatly increased their weight lifting activities after the assault to be better able to defend themselves against men. Seven began abusing anabolic steroids and/or clenbuterol to gain muscle mass. Compulsive weight lifting and anabolic substance abuse may represent another form of response to the trauma of sexual assault.
The pattern of age-related differences in electrophysiological activity of healthy males and females

Age-related differences in quantified electrophysiological measures were examined in 202 subjects (109 females; 93 males) ages 30-80 all of whom were judged to be optimally healthy on a wide variety of criteria. The study utilized both absolute and relative measures from EEG spectral analysis as well as additional measures from long latency-evoked potentials. The same findings were noted for the 109 newly studied females as were reported for 63 previously studied male subjects. Results indicate that there is a broad trend for decreased EEG slow and increased fast activity with age, however, some of the measures change linearly and others are best represented by nonlinear functions. There is no decade where activities remain stable. Overall the pattern of change for males and females is similar, however, gender differences in both the EEG and EP data were present. The females had higher magnitudes for almost all absolute spectral and fast relative spectral measures. However, females demonstrated lower absolute alpha amplitude, lower relative slow activity, and lower late-latency EP data. Moreover, the absolute slow activity measure showed a gender X age interaction, indicating that the females had a different change in pattern of activity with increasing age than the males. Thus, gender-related findings were complex and could not be expressed as simple differences in overall amplitude. Age-related change is not a simple linear process but differs for differing EEG spectral bands, relative, and absolute spectral measures and for males and females. The overall findings contradict the common wisdom that EEG and alpha slow with age and that age related EEG change is on a continuum with findings in Alzheimer's disease where increased slowing predominates.
Quantitative phenotyping of X-disease resistance in chokecherry using real-time PCR

A quantitative real-time SYBR Green PCR (qPCR) assay has been developed to detect and quantify X-disease phytoplasmas in chokecherry. An X-disease phytoplasma-specific and high sensitivity primer pair was designed based on the 16S rRNA gene sequence of X-disease phytoplasmas. This primer pair was specific to the 16SrIII group (X-disease) phytoplasmas. The qPCR method can quantify phytoplasmas from a DNA mix (a mix of both chokecherry and X-disease phytoplasma DNA) at as low as 0.001 ng, 10-fold lower than conventional PCR using the same primer pair. A significant correlation between the copy number of phytoplasmas and visual phenotypic rating scores of X-disease resistance in chokecherry plants was observed. Disease resistant chokecherries had a significantly lower titer of X-disease phytoplasmas than susceptible plants. This suggests that the qPCR assay provides a more objective tool to phenotype phytoplasma disease severity, particularly for early evaluation of host resistance; therefore, this method will facilitate quantitative phenotyping of disease resistance and has great potential in enhancing plant breeding.
How breast cancer treatment decisions are made by women in North Dakota

Abstract Background: Although equally effective, women in rural midwestern states choose modified radical mastectomy (MRM) over breast conservation surgery for early stage breast cancer. This study assessed treatment decisions by the women of North Dakota. Methods: Surveys were sent to women treated for early stage breast cancer from 1990 through 1992. Separate surveys were sent out to surgeons in the state. The questions assessed physician and patient perceptions of treatment and the decision making process. Results: A majority of surgeons believed that the long-term and disease-free survival was equal and that the preference for choosing MRM was due mostly to inconvenience of radiotherapy. The women reported that the surgeon was the most influential in the treatment decision and that concerns over radiation, duration of treatment, and travel restrictions all were factors in the decision. Conclusions: Education of surgeons and patients plus the early involvement of the radiation oncologist in discussing options is essential in the treatment of early stage breast cancer.
Kinetics of transformation for anisotropic particles including shielding effects

A derivation is presented for X(t), the transformed fraction as a function of time, in a phase transformation process which produces randomly oriented anisotropic particles. The key novel element in the development and results is the inclusion of blocking (shielding) effects. The derivation is performed for a 2D system in which symmetrical particles of arbitrary shape are formed. In addition, approximate calculations are performed for X(t) for the case of elliptical particles in order to estimate the influence of growth rate anisotropy upon the magnitude of the blocking effects.
Comparison of Soil Organic Matter in Created, Restored and Paired Natural Wetlands in North Carolina

Soil organic matter (SOM) content is a key indicator of soil quality and is correlated to a number of important soil processes that occur in wetlands such as respiration, denitrification, and phosphorus sorption. To better understand the differences in the SOM content of created (CW), restored (RW), and paired natural wetlands (NWs), 11 CW/RW-NW pairs were sampled in North Carolina. The site pairs spanned a range of hydrogeomorphic (HGM) subclasses common in the Coastal Plain. The following null hypotheses were tested: (1) SOM content of paired CW/RWs and NWs are similar; (2) SOM content of wetlands across different HGM subclasses is similar; and (3) interactions between wetland status (CW/RW vs. NW) and hydrogeomorphic subclass are similar. The first null hypothesis was rejected as CW/RWs had significantly lower mean SOM (11.8 ± 3.9%) than their paired NWs (28.98 ± 8.0%) on average and at 10 out of the 11 individual sites. The second and third null hypotheses were also rejected as CW/RWs and NWs in the non-riverine organic soil flat subclass had significantly higher mean SOM content (31.08 ± 14.2%) than the other three subclasses (8.18 ± 2.5, 11.18 ± 8.2, and 10.38 ± 4.2%). Individual sites within this fourth subclass also had significantly different SOM content. This indicated that it would be inappropriate to include the organic soil flat subclass with either the riverine or non-riverine mineral soil flat subclasses when considering restoration guidelines. These results also suggested that if there is a choice in mitigation options between restoration or creation, wetlands should be restored rather than created, especially those in the non-riverine organic soil flat subclass.
Ge diffusion at the Si(100) surface.

Using scanning tunneling microscopy movies, we directly observe individual embedded Ge atoms to be mobile within the $\mathrm{Si}(100)\mathrm{\text{\ensuremath{-}}}(2\ifmmode\times\else\texttimes\fi{}1)\mathrm{\text{\ensuremath{-}}}\mathrm{Ge}$ surface at temperatures as low as $90\text{ }\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$. We demonstrate that Ge atoms move by exchange diffusion with (1) adsorbed monomers and (2) individual constituent atoms of adsorbed dimers. Our observations are consistent with recent density-functional theory calculations, which give the atomistic pathways and energetic barriers for both exchange mechanisms. We find that neither adsorbed monomers nor dimers can diffuse more than a few nanometers between exchange events, illustrating how Ge diffusion and intermixing are intimately coupled at the nanoscale on the Si(100) surface.
Inkblot content and interpersonal distance

Four HIT content scales were related to a projective and a live measure of interpersonal distance. Based on previous research, negative correlations between human and barrier content and interpersonal distance were predicted, with positive correlations predicted between anxiety and hostility content and distance behavior. All four content scales were found to relate significantly to projective distance, but only anxiety and hostility correlated significantly with distance behavior. The content scales also were combined in regression equations to predict interpersonal distance. The projective measure of interpersonal distance correlated significantly with the live measure of distance. The results were interpreted as support for the construct validity of the inkblot scales.
On the convergence of finite difference methods for PDE under temporal refinement

Abstract In this note we present an issue in the verification of order of convergence for finite difference approximations to partial differential equations discretized in time and space. When one refines both space and time together, the convergence rate for a correct implementation will match that expected from an analysis of the asymptotic convergence rate (or local truncation error) of the method. Sometimes, however, only the time-step size is reduced, while the spatial mesh is held fixed. The observed rate of convergence in this case may then differ from the formal order of accuracy of the method in space–time. In particular, one class of methods, second-order Lax–Wendroff time-differencing, produces only first-order when the time step is refined at fixed spatial mesh resolution because the time and space differencing are intrinsically linked. Our method to arrive at this result is through analyzing the error at a defined point in time associated with many time steps. We demonstrate our results computationally.
Synthesis and structure-activity relationships of trisubstituted phenyl urea derivatives as neuropeptide Y5 receptor antagonists.

1-((1R,2R)-2-Hydroxy-1-methyl-2-phenylethyl)-1-methyl-3-(4-phenoxyphenyl)urea (1) was identified as a hit from the screening of the neuropeptide Y5 (NPY5) receptor. This lead was optimized for in vitro potency by changing the stereochemistry, the phenylethyl segment, the urea portion, and the 4-phenoxyphenyl group on the molecule. Over 40 analogues of 1 were prepared to study the structure−activity relationship for this series. The most potent compounds in this class have IC50s less than 0.1 nM at the NPY5 receptor (e.g., 40f, 44a, and 47). To determine the functional activity for this series of compounds, selected analogues were tested in a cellular assay measuring forskolin-induced cyclic AMP accumulation in 293 cells transfected with the human NPY5 receptor. All urea analogues tested in the functional assay acted as antagonists (e.g., 1, 32, 40a, and 44e).
Properties of a bursting model with two slow inhibitory variables

Models for certain excitable cells, such as the pancreatic $\beta $-cell, must reproduce “bursting” oscillations of the membrane potential. This has previously been done using one slow variable to drive bursts. The dynamics of such models have been analyzed. However, new models for the $\beta $-cell often include additional slow variables, and therefore the previous analysis is extended to two slow variables, using a simplified version of a $\beta $-cell model. Some unusual time courses of this model motivated a geometric singular perturbation analysis and the application of averaging to reduce the dynamics to the slow-variable phase plane. A geometric understanding of the solutionstructure and of transitions between various modes of behavior was then developed. A novel use of the bifurcation code AUTO finds nullclines for the slow variables when the fast variables are periodic by averaging over the fast oscillations. In contrast with the “parabolic” neuronal burster, this model requires bistability in th...
Direct determination of benzo[a]pyrene in water samples by a gold nanoparticle-based solid phase extraction method and laser-excited time-resolved Shpol'skii spectrometry

The strong affinity between polycyclic aromatic hydrocarbons (PAH) and the surface of gold colloids is investigated to device an extraction method for water samples. Within the 20-100 nm particle diameter range, the 20 nm gold nanoparticles showed the best extraction efficiencies for all the studied analytes. The new approach is combined to laser-excited time-resolved Shpol'skii spectrometry for the direct analysis of benzo[a]pyrene in drinking water samples. For a 500 μL sample volume, the analytical figures of merit demonstrate precise and accurate analysis at the parts-per-trillion level. The extraction efficiencies are statistically equivalent to 100% with relative standard deviations lower than 2%. The average recoveries were varied from 87.5% to 96.5% for different concentration of analytes. The simplicity of the experimental procedure, the low analysis cost, and the excellent analytical figures of merit demonstrate the potential of this approach for routine analysis of drinking water samples.
Effectiveness of emWave Biofeedback in Improving Heart Rate Variability Reactivity to and Recovery from Stress

The current study examined the efficacy of heart rate variability (HRV) biofeedback using emWave ,a publicly available biofeedback device, to determine whe- ther training affected physiological tone and stress responses. Twenty-seven individuals aged 18-30 years were randomized to a treatment or no-treatment control group. Treatment participants underwent 4-8 sessions of emWave intervention, and all participants attended pre- treatment and post-treatment assessment sessions during which acute stressors were administered. Physiological data were collected at rest, during stress, and following stress. emWave treatment did not confer changes in tonic measures of HRV or in HRV recovery following stress. However, treatment participants exhibited higher para- sympathetic responses (i.e., pNN50) during stress presen- tations at the post-treatment session than their control counterparts. No treatment effects were evident on self- reported measures of stress, psychological symptoms, or affect. Overall, results from the current study suggest that the emWave may confer some limited treatment effects by increasing HRV during exposure to stress. Additional development and testing of the emWave treatment protocol is necessary before it can be recommended for regular use in clinical settings, including the determination of what physiological changes are clinically meaningful during HRV biofeedback training.
The role of race/ethnicity and race relations on public opinion related to the immigration and crime link

Abstract This article examines two hypotheses related to public opinion concerning immigration and crime. Using data from a recent Gallup poll with oversamples of Hispanics and Blacks, the research examined whether race/ethnicity and race relations matter in the public's opinion of the connection between immigration and crime. After a series of models were performed, results of the final model revealed that race relations, gender (specifically, being male), race/ethnicity, and immigrant status are influential in contextualizing public opinion on the topic. The meaning and policy implications of these findings are also reviewed.
CrowdCamp: rapidly iterating ideas related to collective intelligence & crowdsourcing

The field of collective intelligence - encompassing aspects of crowdsourcing, human computation, and social computing - is having tremendous impact on our lives, and the fields are rapidly growing. We propose a hands-on event that takes the main benefits of a workshop - provocative discussion and community building - and allows time to focus on developing ideas into actual outputs: experiment designs, in-depth thoughts on wicked problems, paper or coded prototypes. We will bring together researchers to discuss future visions and make tangible headway on those visions, as well as seeding collaboration. The outputs from brainstorming, discussion, and building will persist after the workshop for attendees and the community to view, and will be written up.
Tillering responses to red:far-red light ratio during different phenological stages in Eragrostis curvula

Abstract Tillering responses to light quality in different phenological stages of a perennial warm-season grass Eragrostis curvula were investigated in controlled environments. In vegetative plants, the tillering rate was greater (P
Radar determination of the radius of venus.

Venus radius determination from ground based radar range data compared with Mariner 5 and Venera 4 observations and other radar measurements
Effect of cytochalasin B on the biphasic release of insulin in perifused rat islets.

The effect of cytochalasin B on the biphasic pattern of insulin secretion was studied. Islets were isolated from the normal rat pancreas by the collagenase technique and maintained in vitro by perifusion. Cytochalasin B produced a significant increase in the rate of insulin secretion in the first and second phase of glucose-induced insulin release and enhanced significantly the monophasic pattern of release induced by tolbutamide. The drug had no effect on insulin release in the presence of non—stimulatory levels of glucose. The enhancing effect on glucose—induced insulin secretion required the continued presence of cytochalasin B. Removal of the drug during the second phase of glucose—induced insulin secretion resulted in a rapid decline in the rate of insulin release. Islets were perifused with glucose, glucagon and theophylline in order to obtain maximal stimulation of insulin release. Under these conditions of marked stimulation, cytochalasin B did not produce a further significant enhancement of insu...
Biscalitheca suzanneana, N. Sp., from the uppermost Pennsylvanian of Texas

Abstract Biscalitheca suzanneana , n. sp., is described from specimens found in an uppermost Pennsylvanian deposit in north-central Texas. The genus was identified primarily on the basis of impressions of the unique sporangial annuli. The occurrence establishes for Biscalitheca a stratigraphic range equivalent to nearly the entire Upper Pennsylvanian Series.
The second integral of the restricted problem in regularized elements

A perturbation series integral for the restricted problem of three bodies is derived by use of a new set of canonical elements for the regularized two-body problem. These elements are similar to theKS elements of Stiefel and Scheifele, but they contain small parameters other than the semimajor axis. The variable analogous to the longitude of perihelion not only remains well defined as the orbit approaches a circle, but also it can be used as a second small parameter. Regularized elements permit canonical use of the eccentric anomaly as independent variable, but most of the major benefits of regularization in the two-body problem do not carry over to perturbation theory.
Effect of incubation and microbial inhibition at field moisture capacity on changes in DTPA‐extractable Fe, Zn, and Cu in soils of varying pH

Abstract To determine the effect of incubation on DTPA‐extractable Fe, Zn, and Cu in soils with a wide pH range (4.2 ‐ 9.4) and to determine the nature of this effect, soils were incubated at field moisture capacity for 1 week with and without a sterilant (toluene). After incubation these soils as well as their air‐dry counterparts were analyzed for DTPA‐extractable Fe, Zn, and Cu. Incubated soils were significantly lower in DTPA‐extractable Fe, Zn, and Cu than air‐dry soils over all soil pH values tested but there was no significant difference in mean values for incubated soils due to the addition of toluene. The results suggest that, upon incubation at field moisture capacity, the decrease in DTPA‐extractable Fe, Zn, and Cu observed was noa‐microbial in nature.
Unobservability of bispinor two-valuedness in Minkowski space-time

Abstract Currently there is some interest in studying the tensor forms of the Dirac equation to elucidate the physical consequences, if any, of the two-valuedness of bispinors and the possibility of the constrained tensor fields admitting Fermi quantization. In this paper, we first argue that n -particle, square-integrable, positive energy bispinor fields in a Minkowski space-time cannot be physically distinguished from constrained tensor fields. That is, the two-valuedness of bispinors could be observed only by the unphysical superposition of positive and negative energy states, which is forbidden in quantum field theory. We also demonstrate that the bispinor and tensor Hamiltonian systems have equivalent Fermi quantizations. Although the tensor Hamiltonian system is noncanonical, representing the tensor Poisson brackets as commutators for the Heisenberg operators directly leads to Fermi quantization without the use of bispinors.
Using Cognitive Tools to Represent Problems

AbstractThe premise of this paper is that the key to problem solving is adequately representing the problem to be solved. Most research has focused on how problems are (re)presented to learners. The assumption that those external representations naturally map onto learners’ internal representations of problems has not been confirmed. New research has examined the role of tools for externalizing learners’ internal representations. Descriptions of how three kinds of cognitive tools—semantic networks, expert systems, and systems modeling tools—can be used to externalize learner’s internal representations are provided. Research is needed to study the efficacy of these tools for supporting problem solving.
Convective Transport in Nanofluids

Nanofluids are engineered colloids made of a base fluid and nanoparticles (1-100 nm). Nanofluids have higher thermal conductivity' and single-phase heat transfer coefficients than their base fluids. In particular the heat transfer coefficient increases appear to go beyond the mere thermal-conductivity effect, and cannot be predicted by traditional pure-fluid correlations such as Dittus-Boelter's. In the nanofluid literature this behavior is generally attributed to thermal dispersion and intensified turbulence, brought about by nanoparticle motion. To test the validity of this assumption, we have considered seven slip mechanisms that can produce a relative velocity between the nanoparticles and the base fluid. These are inertia, Brownian diffusion, thermophoresis, diffusioplwresis, Magnus effect, fluid drainage, and gravity. We concluded that, of these seven, only Brownian diffusion and thermophoresis are important slip mechanisms in nanofluids. Based on this finding, we developed a two-component four-equation nonhomogeneous equilibrium model for mass, momentum, and heat transport in nanofluids. A nondimensional analysis of the equations suggests that energy transfer by nanoparticle dispersion is negligible, and thus cannot explain the abnormal heat transfer coefficient increases. Furthermore, a comparison of the nanoparticle and turbulent eddy time and length scales clearly indicates that the nanoparticles move homogeneously with the fluid in the presence of turbulent eddies so an effect on turbulence intensity is also doubtful. Thus, we propose an alternative explanation for the abnormal heat transfer coefficient increases: the nanofluid properties may vary significantly within the boundary layer because of the effect of the temperature gradient and thermophoresis. For a heated fluid, these effects can result in a significant decrease of viscosity within the boundary layer, thus leading to heat transfer enhancement. A correlation structure that captures these effects is proposed.
Controlling nanotube dimensions: correlation between composition, diameter, and internal energy of single-walled mixed oxide nanotubes.

Control over the diameter of nanotubes is of significance in manipulating their properties, which depend on their dimensions in addition to their structure and composition. This aspect has remained a challenge in both carbon and inorganic nanotubes, since there is no obvious aspect of the formation mechanism that allows facile control over nanotube curvature. Here we develop and analyze a quantitative correlation between the composition, diameter, and internal energy of a class of single-walled mixed oxide aluminosilicogermanate (AlSiGeOH) nanotubes. A series of synthetic AlSiGeOH nanotubes with varying Si/Ge ratio are characterized by X-ray photoelectron spectroscopy, vibrational spectroscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction to relate their compositions and diameters. We then study these nanotubes computationally by first parametrizing and validating a suitable interatomic potential model, and then using this potential model to investigate the internal energy of the nanotube a...
An analysis of information search strategies for decision making

Understanding how people search and combine information to make decisions is an important concern in the study of decision making because people tend to search information consistent with the decision process employed. Thus, analysis of these search strategies provides insight into the decision process, and into the design of computerbased aids for decision making.
Endocrine influence on hypercalcemic regulation in bullfrog tadpoles.

Abstract Tadpoles of the bullfrog, Rana catesbeiana , adapted to fresh water at different concentrations of calcium and sodium had similar plasma calcium levels. This would indicate rather efficient regulating mechanisms for this ion. Tadpoles kept in tap water exhibited hypocalcemia after parathyroidectomy. Surgical removal of the pituitary gland in tadpoles adapted to low-sodium and low-calcium levels also produced hypocalcemia and hyponatremia. When the animals were kept in 0.3% sodium chloride solution, hypophysectomy produced only hypocalcemia but not hyponatremia. This suggests that the pituitary gland in tadpoles is involved in calcium regulation. Prolactin injections into tadpoles adapted to high-calcium and high-sodium water elicited significant hypercalcemia. It seems that in tadpoles both the parathyroid and the pituitary glands are important in plasma calcium regulation.
Corticotropin-releasing hormone challenge in prepubertal major depression

This study investigates cortisol and ACTH (corticotropin) responses to an infusion of human CRH (corticotropin-releasing hormone) in prepubertal children with major depressive disorder (MDD). Following a period of 24 hours of adaptation to the laboratory environment with an intravenous catheter in place, 34 children with MDD and 22 healthy controls received 1 μ g/kg of human CRH at 5:00 PM. Blood samples for cortisol and ACTH were measured at baseline and post-CRH. Overall, there were no significant differences between the MDD and the normal controls in baseline or post CRH stimulation values of either cortisol or ACTH. Melancholic ( n = 4) patients had significantly higher baseline cortisol levels than nonmelancholic ( n = 24) patients. Compared with the outpatients and the nonmelancholics, the inpatients ( n = 10) and the melancholics showed significantly lower total ACTH secretion (effect size: 0.9 and 1.4, respectively) after CRH infusion. These results are consistent with a broad literature suggesting that the HPA axis abnormalities occur less frequently in early-onset depression than reported in adult studies. The pattern of results in the subgroups of inpatients and in melancholic children, however, raise questions about possible continuities with adult studies.
Model updating by adding known masses

New approaches are developed that use measured data to adjust the analytical mass and stiffness matrices of a system so that the agreement between the analytical modes of vibration and the modal survey is improved. By adding known masses to the structure of interest, measuring the modes of vibration of this mass-modified system, and finally using this set of new data in conjunction with the initial modal survey, the analytical mass matrix of the structure can be corrected, after which the analytical stiffness matrix can be readily updated. By manipulating the correction matrices into vector forms, the connectivity information can be enforced, thereby preserving the physical configuration of the system and reducing the sizes of the least-squares problems that need to be solved. Solution techniques for updating the system matrices are introduced, and the numerical issues associated with solving overdetermined and underdetermined least squares problems are investigated. The effects of round-off errors are also studied, and heuristic criteria are given for determining the minimum number of modes that need to be measured in order to ensure sufficiently accurate updated mass and stiffness matrices. Numerical experiments are presented to validate the proposed model-updating techniques, to illustrate the effects of the number of measured modes on the quality of the updated model, to show how the magnitudes and locations of the added masses influence the updated matrices, and to highlight the numerical issues discussed in this paper. Copyright © 2001 John Wiley & Sons, Ltd.
Analog Network Coding in the High-SNR Regime

A node performing analog network coding simply forwards a signal it receives over a wireless channel. This allows for a (noisy) linear combination of signals simultaneously sent from multiple sources to be forwarded in the network. As such, analog network coding extends the idea of network coding to wireless networks. However, the analog network coding performance is limited by propagated noise, and we expect this strategy to perform well only in high SNR. In this paper, we formalize this intuition and determine high-SNR conditions under which analog network coding approaches capacity in a layered relay network. By relating the received SNR at the nodes with the propagated noise, we determine the rate achievable with analog network coding. In particular, when all the received powers are lower bounded by 1/δ, the propagated noise power in a network with L layers is of the order Lδ. The result demonstrates that the analog network coding approaches the cut-set bound as the received powers at relays increase. As all powers in the network increase, the analog network coding rate is within a constant gap from the upper bound. The gap depends on number of nodes. We further demonstrate by an example that analog network coding can perform close to sum-capacity also in the multicast case.
The role of host endocrine factors in the development of polyembryonic parasitoids

Abstract Polyembryony is a form of development in which a single egg gives rise to multiple individuals. In the Hymenoptera, polyembryonic species are found in the families Braconidae, Platygasteridae, Encyrtidae, and Dryinidae. The host ranges, morphology, and number of progeny produced per egg differ considerably among polyembryonic species, but they all appear to share a few developmental features. Most importantly, development can be divided into a proliferative phase in which multiple embryos form and a differentiation phase in which each embryo synchronously initiates morphogenesis and develops into a larva. Examination of the literature strongly suggests that morphogenesis in polyembryonic parasitoids is synchronized with the stage at which the host molts to its final (ultimate) stadium and larval development is completed when the host initiates metamorphosis (holometabolous species) or molts to the adult stage (hemimetabolous species). More detailed studies with the polyembryonic encyrtid Copidosoma floridanum in its host, Trichoplusia ni, further indicate that embryo proliferation is synchronized with the host molting cycle and morphogenesis occurs after a large drop in the host juvenile hormone (JH) titer in the fourth (penultimate) stadium. Neck ligation of third stadium hosts prior to the critical period inhibited proliferation of C. floridanum embryos, whereas injection of 20-hydroxyecdysone stimulated proliferation. Application of the JH analog methoprene to the host during the fourth stadium delayed embryo morphogenesis, but the anti-JH fiuoromevalanolactone induced precocious morphogenesis.
Piezoluminescence from a ferroelectric polymer and quartz

Abstract Piezoluminescence has been observed from polyvinylidene fluoride, a ferroelectric polymer, and from quartz not previously irradiated in the laboratory. The light was imaged using a CCD camera in addition to being recorded by a photomultiplier.
Gradient-enhanced FAWSETS perfusion measurements.

Abstract This work describes the use of custom-built gradients to enhance skeletal muscle perfusion measurements acquired with a previously described arterial spin labeling technique known as FAWSETS (flow-driven arterial water stimulation with elimination of tissue signal). Custom-built gradients provide active control of the static magnetic field gradient on which FAWSETS relies for labeling. This allows selective, 180° modulations of the phase of the perfusion component of the signal. Phase cycling can then be implemented to eliminate all extraneous components leaving a signal that exclusively reflects capillary-level perfusion. Gradient-enhancement substantially reduces acquisition time and eliminates the need to acquire an ischemic signal to quantify perfusion. This removes critical obstacles to application of FAWSETS in organs other than skeletal muscle and makes the measurements more desirable for clinical environments. The basic physical principles of gradient-enhancement are demonstrated in flow phantom experiments and in vivo utility is demonstrated in rat hind limb during stimulated exercise.
A computer analysis of cardiac electrograms

Abstract Computer programs were constructed for the temporal analysis of 8 electrograms obtained from various regions of isolated dog hearts. The electrograms were recorded on photosensitive paper. A computer program written in the Fortran II language allowed an x − y digitizing table to be used to input the coordinates of each electrogram into a computer. Each electrode recording within a given cardiac cycle was digitized in this manner, and the temporal intervals between the 28 combinations of electrode pairs were calculated. The program also computed the heart rate and cardiac cycle length. Subroutine options permitted the grouping of data into experiment, record, and event numbers. All data were stored on a magnetic disk. A separate computer program written in the Fortran IV language performed basic statistical operations on each of the data files. The computer system described in the present report accurately and reliably processed over 10,000 cardiac cycles. Such a system can be used to analyze large amounts of data from sources other than electrograms. Temporal analysis of the standard electrocardiogram is offered as an example of the versatility of the programs.
Schottky Defects in Solid Solutions

IN the various statistical thermodynamic treatments of substitutional solid solutions, it is tacitly assumed that the number of unoccupied lattice sites in the solution is either zero or the same as the number in the separated components. This assumption seems unsatisfactory on general grounds, and is, in fact, not supported by experiment. The nickel–aluminium system is in this respect a spectacular case, since at some compositions in the β-phase vacancies occur1 in excess of 5 per cent. This system is, however, atypical in that, among other things, the vacancies seem to originate in special electronic effects, since the fraction of unoccupied sites varies with composition in such a way that the number of conduction electrons per unit cell is maintained constant. Schottky defects in alkali halide solid solutions have a simpler origin. The distribution over a group of lattice sites of two or more ions differing appreciably in size introduces stresses which lead to local lattice distortions and the occasional ejection of an ion.
Cloning and expression of a streptavidin-lipase fusion gene in Escherichia coli and characterization of the immobilized fusion protein

Abstract A gene for a streptavidin-lipase fusion protein was constructed by cloning a PCR-modified Pseudomonas fluorescens B52 lipase gene into a streptavidin chimeric protein expression vector, pStp4. The plasmids, pSTLP1 or pSTLP2, were used to transform Escherichia coli NM522 or DH5α. Plasmid pSTLP2, which contains a lacl q gene upstream from the promoter, gave better expression of the bifunctional fusion protein when the cells were induced. Correct insertion of the fused gene was confirmed by DNA sequencing of the linker region and the lipase gene, by identification of a protein band of the correct molecular size (66 kDa) on SDS-PAGE, and by Western blot analysis using antistreptavidin antibody. Streptavidin-lipase fusion protein was purified and immobilized in a single step from recombinant cell lysates by bioselective adsorption on 6-(biotinamido)hexanamidopropyl-controlled pore glass. The hydrolytic activity of the resulting immobilized enzyme exhibited a pH optimum between 7 and 8 and a preference for short-chain fatty acids. Comparison of the hydrolytic activity of immobilized B52 lipase with that of commercial SAM-2 lipase from P. fluorescens suggests that about 30% of the activity was retained upon immobilization. Transesterification of tricaprylin with oleic acid in hexane by immobilized lipase indicated that 11% of the reaction products were derived from transesterification.
Artificial tongues: tastes good to me.

The mammalian sense of taste has an exquisite ability to differentiate subtle variations in flavour. An artificial tongue has now been developed with the ability to amplify and sense analytes that before may have gone unnoticed.