cssi/SciSciGPT-SciSciNet huggingface dataset:
Sulfide mineralogy and sulfur isotope geochemistry of layered sills in the Deer Lake Complex, Minnesota

The Deer Lake Complex, located in north-central Minnesota, consists of a series of layered peridotite-pyroxenite-gabbro sills. Sulfide minerals occur as fine disseminations throughout pyroxenite and gabbro units, and occur more sporadically in peridotite and basal chilled margin units. Sulfide volume percentage rarely exceeds 0.5. A distinct zonation in sulfide mineralogy and sulfur isotopic composition characterizes the sills. Cobaltian pentlandite is the dominant sulfide mineral in peridotite (pd) units, with Ni-enrichment most likely linked to the serpentinization process. δ34Spd values are variable, ranging from −3.5 to +2.8‰. Sulfide assemblages in pyroxenite (px) and lower gabbro units consist of chalcopyrite, pyrrhotite, and minor pentlandite. δ34Spx values range from −1 to +1 ‰. Pyrite is the principal sulfide mineral in upper gabbro (μg) units. Its origin may be related to increased f02 conditions of the remaining melt and to reaction between a S-bearing volatile phase and mafic silicates. δ34Sug values range from 1 to 3.5 ‰. Sulfur isotopic values of chilled margin (2–9 ‰) and peridotite units, together with the erratic spatial distribution of sulfide minerals in these zones, suggests that the parent magma was not initially saturated with sulfur, and that local sulfide concentrations are the result of incorporation of sulfur derived from metasedimentary country rocks. Sulfide saturation was more uniformly reached during pyroxenite formation, with contained sulfur being of magmatic origin. Enrichment in 34S of pyrite from upper gabbro may be explained by buildup of isotopically heavy sulfur following a Rayleigh process, coupled with possible involvement of a SO2-rich fluid phase during hydrothermal alteration.
Texas Community College Graduation and Persistence Rates as a Function of Student Ethnicity.

In this investigation, the graduation and persistence rates of Texas community college students by ethnic membership (i.e., White, Black, Hispanic, and Asian) for the 2000, 2004, 2005, 2006, 2007, 2008, 2009, and 2010 academic years were examined. Statistically significant differences were present between the 2000 and the 2010 graduation and persistence rates for all four ethnic groups. Trends were also revealed for the graduation and persistence rates for all ethnic groups between the 2000 and the 2010 academic years. Results were congruent with the results of other researchers concerning differences in the graduation and persistence rates between White students and their Black and Hispanic counterparts.
A convex pseudolikelihood framework for high dimensional partial correlation estimation with convergence guarantees

Author(s): Khare, K; Oh, SY; Rajaratnam, B | Abstract: Sparse high dimensional graphical model selection is a topic of much interest in modern day statistics. A popular approach is to apply l1-penalties to either parametric likelihoods, or regularized regression/pseudolikelihoods, with the latter having the distinct advantage that they do not explicitly assume Gaussianity. As none of the popular methods proposed for solving pseudolikelihood-based objective functions have provable convergence guarantees, it is not clear whether corresponding estimators exist or are even computable, or if they actually yield correct partial correlation graphs. We propose a new pseudolikelihood-based graphical model selection method that aims to overcome some of the shortcomings of current methods, but at the same time retain all their respective strengths. In particular, we introduce a novel framework that leads to a convex formulation of the partial covariance regression graph problem, resulting in an objective function comprised of quadratic forms. The objective is then optimized via a co-ordinatewise approach. The specific functional form of the objective function facilitates rigorous convergence analysis leading to convergence guarantees; an important property that cannot be established by using standard results, when the dimension is larger than the sample size, as is often the case in high dimensional applications. These convergence guarantees ensure that estimators are well defined under very general conditions and are always computable. In addition, the approach yields estimators that have good large sample properties and also respect symmetry. Furthermore, application to simulated and real data, timing comparisons and numerical convergence is demonstrated. We also present a novel unifying framework that places all graphical pseudolikelihood methods as special cases of a more general formulation, leading to important insights.
The Tug-of-War between Cash Flow and Institutional Values in a College-Seminary Merger.

This case study documents the merger of a liberal arts college and a seminary, with particular attention to fiscal aspects of the venture. The interaction of Friends Regional University (FRU) with its seminary offers important theoretical lessons because of the interplay of three factors:1) FRU has a strong institutional context based on the evangelical Christian identity of the school. The undergraduate program was created more than one century ago as a Christ-centered opportunity for young people to integrate their faith and learning.2) From 1986, FRU had become more dependent on adult programming to meet its budgetary commitments. The adult programs also served to broaden institutional scope in the transition from college to university.3) Furthermore, throughout the history of FRU, the leadership had a strongly developed perceptual schema shaped by their evangelical Christian faith and lifestyles. Tension between the institutional perspective and resource dependency was evident in how FRU dealt with it...
Calbindin-D28k immunoreactive neurons form two populations in the rat nucleus accumbens: a compartmental study

This study shows localisation of a second class of calbindin-D28k containing neuron other than the medium-sized spiny neuron in the rat nucleus accumbens, using immunohistochemistry with monoclonal antibodies. Ultrastructural characteristics were used to identify this second population of accumbens neurons within its compartments. Staining with NADPH-diaphorase and calbindin-D28k immunoreactivity revealed that some neurons contained both markers.
Effects of invasive macrophytes on freshwater fish and macroinvertebrate communities: the role of invasive plant traits

Biological invasions of aquatic plants (i.e., macrophytes) are a worldwide phenomenon, and within the last 15 years researchers have started to focus on the influence of these species on aquatic communities and ecosystem dynamics. We reviewed current literature to identify how invasive macrophyte species impact fishes and macroinvertebrates, explore how these mechanisms deviate (or not) from the accepted model of plant–fish interactions, and assess how traits that enable macrophytes to invade are linked to effects on fish and macroinvertebrate communities. We found that in certain instances, invasive macrophytes increased habitat complexity, hypoxia, allelopathic chemicals, facilitation of other exotic species, and inferior food quality leading to a decrease in abundance of native fish and macroinvertebrate species. However, mechanisms underlying invasive macrophyte impacts on fish and macroinvertebrate communities (i.e., biomass production, photosynthesis, decomposition, and substrate stabilization) were not fundamentally different than those of native macrophytes. We identified three invasive traits largely responsible for negative effects on fish and macroinvertebrate communities: increased growth rate, allelopathic chemical production, and phenotypic plasticity allowing for greater adaptation to environmental conditions than native species. We suggest that information on invasive macrophytes (including invasive traits) along with environmental data could be used to create models to better predict impacts of macrophyte invasion. However, effects of invasive macrophytes on trophic dynamics are less well-known and more research is essential to define system level processes.
Coordinate activity in retinal and cortical development

New approaches for detecting and manipulating patterns of neuronal activity have revealed diverse strategies for constructing circuits in the developing brain. Spontaneously generated patterns can provide activity-based information before the onset of sensory inputs. In addition to mechanisms based on chemical synaptic communication, coordination of activity via gap junctions can provide important cues for synchronous activity early in circuit formation.
A Stability Criterion for an Artificial Earth Satellite

The equation of rotation of the spacecraft about a set of control axes are developed to reveal the required functions of a momentum exchange control system when subjected to external disturbances. A linear control system is designed and the three-axis characteristic equation is developed. This ninth order equation has coefficients which vary with the particular attitude references in use, and with the particular desired attitude. The number of and location of the references are variables. Reference information and commanded attitude data are lumped into two constants and lines of constant minimum system damping are plotted parametricly. Thus before slewing to a new attitude, the degree of damping or instability may be readily determined.
Vocational behavior and career development, 1977: A review

Abstract This review covers several books and selections from several journals published in 1977 on topics in vocational behavior and career development. Coverage includes theoretical contributions in vocational choice, development and correlates of choice, decision and indecision, assessment of career skills and interests, self-estimates, and sex bias. Material relating to the vocational behavior of adults contains sections on theory, satisfaction, performance, career development, and mid-career change. A final section is devoted to a review of studies of interventions.
Collateral-free lending with risk-contingent credit for agricultural development: indemnifying loans against pulse crop price risk in India

This article addresses the problem of collateralâfree lending in the context of agricultural development. We investigate a viable alternative to traditional credit products through the development of riskâcontingent credit for operating loans and farm mortgages and apply the concept to agricultural loans for pulse crops in India. Riskâcontingent credit mitigates business and financial risk by reducing debt obligations depending on the embedded commodity options whose payoffs are linked with commodity price fluctuations. We analyze daily commodity spot prices for pulse crops in India and show how riskâcontingent structured financial instruments can be priced in practice.
Displacement sensing with hetero-core fiber specklegram

ABSTRACT In this paper we report the design and implementation of a multimode fiber sensing technique for displacement sensing. To exploit the spatial information contents for sensing, a multimode fiber specklegram sensor with a hetero-core fiber structure is used. The sensor utilizes the inner product of multimode fiber speckle fields, which is highly sensitive on the geometrical shape change of the sensing section. The sensitivity and the dynamic range of the displacement sensing are investigated for hetero-core structure fiber specklegram sensor and straight multimode fiber specklegram sensor. Itis found that the sensitivity of the hetero-core FSS offers sensitivity as high as 0.1 µ m, with a dynamic range of about 3 µ m, which is superior to straight structure multimode fiber FSS. Dynamic response of the hetero-core FSS for displacement sensing was also studied. Keywords: fiber specklegram, fiber sensing, hetero-core fiber, displacement sensing, multispeckle pattern
An Engineering Approach to Thermal‐stress Analysis in SMT Applications

This paper introduces thermal‐stress analysis methods which follow electrical engineering procedures. The spring constant or c‐value is found to be related to the electrical impedance, combining dimensions and material characteristics in a performance parameter which simplifies calculations. Voltage is used to represent thermal deformation, and thermal forces are modelled as currents. Relationships equivalent to Ohm's Law are applied to calculate thermal stresses in leads or traces of surface‐mount assemblies. The thermal performance of laminates, e.g., thermal expansion coefficients of interconnect boards with a restraining core, and the thermal stresses in the bonded layers, are derived from the analysis of an electrical network which represents the composite structure. The method provides visual concepts which facilitate a first‐order solution of engineering problems related to thermal stress.
"The great question in agitation": George Bentham and the origin of species

ABSTRACT George Bentham initially expressed reservations about Darwin's Origin of species (1859). What most troubled Bentham was the potentially disruptive nature of Darwin's ideas for natural history. Bentham, renowned even among other naturalists for always proceeding with the utmost intellectual caution, decided to ignore Darwin's theory. This reticence disappointed Darwin, who pressured Bentham unsuccessfully to give an assessment of the Origin. Bentham did, however, publicly praise Darwin's work on the fertilisation of orchids as an ideal model for natural history research. Finally, in his 1863 presidential address to the Linnean Society, Bentham directly addressed “the great question in agitation”, evolution. His judicious praise of the Origin would, Darwin was convinced, “do more to shake the unshaken & bring on those leaning to our side, than anything written directly in favour of transmutation.” Bentham's tentative conversion to evolution came only after Darwin's work, particularly on orchids, co...
Visualizing patterns of neurological disease progression with PET

By applying non-conventional statistical analysis and visualization techniques to PET data obtained from a combined group of patients and normals, we are able to illustrate topographic covariance profiles unique to the disease at various stages of progression. Each profile represents a neuroanatomical regional network that is not discernible in the unprocessed data sets using standard analytical methods. The magnitude of a profile's manifestation in a given subject is expressed as a subject score which can correlate with independent clinical disease severity measures such as quantitative rigidity and bradykinesia ratings in Parkinson's disease. To create representations of these profiles a semi-automated routine is used which first generates a 2D pseudocolor map of the network where each region is weighted in accordance with its relative contribution to the overall profile. This representation is then transformed to a 3D isometric form so that the metabolic topography becomes more visually apparent. To fully perceive the evolving topographical pattern from initial to final stages of the disease, intermediate stages of disease progression are derived by interpolation to create a smooth progression of images that are displayed in an animated sequence.
Vibrotactile masking: A comparison of energy and pattern maskers

Subjects were required to identify vibrotactile patterns presented to their fingertips. The patterns, letters of the alphabet, were presented singly or in the presence of other vibrotactile masking stimuli. Two types of masking stimuli were used: an energy masker and a pattern masker. The effectiveness of these two types of maskers in interfering with letter recognition was tested, using them as forward and as backward maskers and presenting them at several different levels of intensity. The results showed more masking by the pattern masker, more backward than forward masking, and more masking as intensity increased. In addition, compared with the energy masker, the pattern masker showed both a greater difference between forward and backward masking and a greater increase in masking as masker intensity increased. The results are discussed in terms of a two-factor model of vibrotactfle masking.
Characterization of a polypropylene/super-absorbent web by NMR diffusion studies

Super-absorbent fiber has the property of absorbing moisture up to several thousand times its original weight, undergoing significant expansion, and eventually becoming a gel. The hydrophilic super-absorbent fiber is usually blended with hydrophobic polymer fiber to form a polymer web with the ability to attract fluid and also to hold it under pressure. Because of the confining influence of pore boundaries on molecular translation, restricted diffusion measurements on fluids in porous systems, such as the super-absorbent web, contain important information about the pore morphology. In this work, we studied the diffusion of water in a web of super-absorbent polyacrylate and polypropylene fiber. We observed restricted diffusion of the water by means of the pulsed-field-gradient spin-echo (PFGSE) NMR technique. Several mathematical models were used to interpret the data and yield estimates of the gross pore dimensions and the surface-to-volume ratio of the pores.
Effects related to synchrony and repertoire in perceptions of robot dance

In this work we identify low-level aspects of robot motion that can be exploited to create impressions of agency and lifelikeness. In two experiments, participants view split-screen videos of multiple robots set to music and rate the robots on their dance ability, lifelikeness, and entertainment value. The first experiment tests the impact of the correspondence (or lack thereof) of the robot's motion to the underlying rhythm of the music, and the effect of matching changes in the robot's movement to changes in the music, such as a phrase of vocals or drumming. This motivates a second experiment which more deeply explores the relationships of asynchrony and changes in motion repertoire to participants' perceptions of the lifelikeness of the robot's motion. Findings indicate that perceptions of the lifelikeness of the robot and the quality of the dance can be manipulated by simple changes, such as variation in the repertoire of motions, coordination of changes in behavior with events in the music, and the addition of flaws to the robot's synchrony with the music.
Enzyme product blot for nondestructive assay of protein catalytic function in polyacrylamide gels

A new method that permits rapid, sensitive, and specific enzymatic assay of proteins in polyacrylamide gels is described. The enzyme product blot described in this report involves percolation of the reaction mixture through a gel containing native enzyme which converts the labeled substrate to a labeled product with differing chemical properties. A permeable membrane with specific ligand-binding properties overlies the gel and binds the enzyme product, but not the substrate, as reaction mixture is blotted vertically. This membrane is washed free of substrate and the location of the product is identified by autoradiography. The autoradiogram is compared with the stained gel in order to recover the enzyme for amino acid sequence analysis. The enzyme product blot is demonstrated using glycerol kinase and hexokinase.
Momentum analyticity and finiteness of compactified string amplitudes Part I: Tori

Abstract We generalize to the case of compactified superstrings a construction given previously for critical superstrings of finite one-loop amplitudes that are well defined for all external momenta. The novel issues that arise for compactified strings are the appearance of infrared divergences from the propagation of massless strings in four dimensions and, in the case of orbifold schemes, the contribution of tachyons in partial amplitudes with given spin structure and twist sectors. Methods are presented for the resolution of both problems and expressions for finite amplitudes are given in terms of double and single dispersion relations, with explicit spectral densities.
Commentary on Causal Prescriptive Statements.

Causal prescriptive statements are valued in the social sciences when there is the goal of helping people through interventions. The articles in this special issue cover different methods for testing causal prescriptive statements. This commentary identifies both virtues and liabilities of these different approaches. We argue that it is extremely difficult to confirm causal prescriptive statements because of the potentially infinite number of third variables in causal relationships and of confounding variables in experimental manipulations. All methodological approaches, including randomized control trials, have a simple view of causality that does not adequately solve the challenges of indeterminacy, interactions, combinatorial explosion, and dynamics. However, these challenges should not discourage researchers from formulating and testing causal prescriptive statements.
Closing the Paradigm Gap Separating Worker and Student Support

Presents scenarios which illustrate the functionality of digitally distributed competence (DC). Explains that Performance Base Learning (PBL) is premised on the use of DC to support increments in human learning and makes a case for DC‐supported PBL in education. Explores the challenges faced by the workforce that have resulted in expanded uses of DC and argues that these challenges provide clear guidelines for the renovation and revitalization of education services in countries such as the United States. Concludes that in the PBL paradigm, learning is a Just‐In‐Time event that occurs in the moment of performance or in highly detailed Just‐Ahead‐of‐Time simulations that are continually revised by smart DC software.
Bionic sonar for target detection

A variety of experimental results indicate that dolphins possess a unique and sophisticated sonar system. In addition, this sonar system is highly adaptive in detecting, discriminating, and recoginizing objects in highly reverberating and noisy environments. In this paper a new approach using resonance scattering theory in target detection and recognition is presented. The results seems to imply that this approach may be useful in minelike target detection and identification.
Backscattering Interferometry: Seeing Membrane Proteins in a New Light

The interaction of membrane proteins with and within lipid membranes is vital to a plethora of cellular processes from the control of intracellular signaling by peripheral membrane proteins, to the activity of antimicrobial peptides and integral membrane proteins. Thus, quantifying the mechanism by which proteins interact with and within lipid membranes is essential to understanding their biological functions. However, many protein-lipid and protein-protein interactions remain poorly understood due to the difficulty in studying processes that occur at the membrane surface. There is thus a clear need for a sensitive, versatile, non-perturbing and physiologically-relevant biophysical method capable of measuring association constant and stability free energy of membrane proteins in a wide range of conditions and matrices.Backscattering interferometry (BSI) is an analytical technique that can monitor and quantify molecular interactions through the detection of small changes in refractive index (RI) induced by molecular interaction. BSI offers many advantages over current techniques including: no need for label or surface immobilization, small sample sizes (1-2 µL), low concentrations (pM to µM), remarkable sensitivity, broad dynamic range for dissociation constant, and low cost. Here, the potential application of BSI in the field of membrane proteins is illustrated through three case studies: (1) Association of small peptides with lipid vesicles, (2) transmembrane helix dimerization, and (3) unfolding of integral membrane proteins. Our preliminary results suggest that BSI is amenable to the study of such systems.
Evaluating air carrier fuel efficiency in the US airline industry

Abstract We employ ratio-based, deterministic, and stochastic frontier approaches to investigate fuel efficiency among 15 large jet operators (mainline airlines) in the US. Given the hub-and-spoke routing structure and the consequent affiliation between mainline and regional carriers, we consider not only fuel efficiency of individual mainline airlines, but also the joint efficiency of each mainline and its regional subsidiaries, as well as efficiency in transporting passengers from their origins to destinations. We find that: (1) airline fuel consumption is highly correlated with, and largely explained by, the amount of revenue passenger miles and flight departures it produces; (2) depending on the methodology applied, average airline fuel efficiency for the year 2010 is 9–20% less than that of the most efficient carrier, while the least efficient carriers are 25–42% less efficient than the industry leaders; (3) regional carriers have two opposing effects on fuel efficiency of mainline airlines: higher fuel per revenue passenger mile but improved accessibility provision; (4) the net effect of routing circuity on fuel efficiency is small; (5) potential cost savings from improved efficiency for mainline airlines can reach the magnitude of billion dollars in 2010.
Neutral and Cationic Group 4 Metal Compounds Containing Octamethyldibenzotetraazaannulene (Me8taa2-) Ligands. Synthesis and Reactivity of (Me8taa)MX2 and (Me8taa)MX+ Complexes (M = Zr, Hf; X = Cl, Hydrocarbyl, NR2, OR)

The synthesis and reactivity of out-of-plane (Me8taa)MX2 and (Me8taa)MX+ complexes (M= Zr, Hf; X= Cl, hydrocarbyl, NR2, OR) containing the dianionic tetraaza-macrocycle ligand octamethyldibenzotetraazaannulene (Me8taa2-) are described. The reaction of [Li(Et2O)]2[Me8taa] (1) with MCl4(THF)2 yields (Me8taa)MCl2 complexes (2a, M = Zr; 2b, M = Hf). Alkylation of 2a,b with LiCH2SiMe3 or LiMe in hydrocarbon solvents yields (Me8taa)M(CH2SiMe3)2 (3a, M = Zr; 4a, M = Hf) or (Me8taa)MMe2 (3b, M = Zr; 4b, M = Hf) complexes. Compound 3b rearranges by migration of a Me group from Zr to a Me8taa imine carbon in coordinating solvents. The reaction of (Me8taa)H2 with the appropriate ZrR4 compound yields (Me8taa)Zr(CH2Ph)2 (3c) and (Me8taa)Zr(CH2CMe3)2 (3d). The reaction of (Me8taa)H2 and Zr(NR2)4 yields (Me8taa)Zr(NR2)2 (6a, R = Me; 6b, R = Et). Spectroscopic data for (Me8taa)MX2 compounds 2, 3, 4, and 6 are consistent with cis, C2v-symmetric structures. Dialkyl complexes 3 and 4 and bis(amide) complexes 6 react with ch...
A burst emission mechanism for coherent radiation from pulsars

Various mechanisms for generating coherent curvature radiation have been proposed1 to explain the high brightness temperature of pulsars at radio frequencies. The bunching of counterstreaming charged particles2–5, although requiring rather special conditions and subject to criticism6, has hitherto seemed the most plausible. Here we propose an entirely new mechanism of ‘burst emission’, which initiates at the surface of a neutron star and occurs naturally without any need to postulate special conditions. We argue that the induced electric field in the near magnetosphere of a rotating neutron star is sufficiently strong to detach moderately large grains of solid matter from the surface in the polar-cap regions. The detached grains erupt and form ascending plumes or jets of dense and highly charged gas. These thread-like plumes, of length h ≳ 102 cm, then accelerate along the open magnetic field lines and emit intense partially coherent radiation, at radio frequencies, with a low-frequency cutoff at c/h. Our estimates indicate that burst emission can account for the principal characteristics of the observed radiation from pulsars at radio frequencies.
Exploiting functional relationships in musical composition

The ability of gifted composers like Mozart to create complex multipart musical compositions with relative ease suggests a highly efficient mechanism for generating multiple parts simultaneously. Computational models of human music composition can potentially shed light on how such rapid creativity is possible. This article proposes such a model based on the idea that the multiple threads of a song are temporal patterns that are functionally related, which means that one instrument's sequence is a function of another's. This idea is implemented in a program called NEAT Drummer that interactively evolves a type of artificial neural network called a compositional pattern-producing network, which represents the functional relationship between the instruments and drums. The main result is that richly textured drum tracks that tightly follow the structure of the original song are easily generated because of their functional relationship to it.
The effects of alternative positioning on preterm infants in the neonatal intensive care unit: a randomized clinical trial.

Abstract There is a paucity of studies that have investigated the developmental benefits of positioning in the neonatal intensive care unit. The purpose of this study was to investigate the effects of a new, alternative positioning device compared to traditional positioning methods used with preterm infants. In this randomized, blinded clinical trial, one hundred preterm infants (born ≤32 weeks gestation) from a level III neonatal intensive care unit in the United States were enrolled at birth. Participants were randomized to be positioned in the alternative positioning device or to traditional positioning methods for their length of stay in the neonatal intensive care unit. Infants were assessed using the NICU Network Neurobehavioral Scale between 35-40 weeks postmenstrual age. Clinical and feeding outcomes were also captured. Linear and logistic regressions were used to investigate differences in neurobehavioral outcome, feeding performance, and medical outcomes. Infants in the alternative positioning arm of the study demonstrated less asymmetry of reflex and motor responses on the NICU Network Neurobehavioral Scale (p = 0.04; adjusted mean difference = 0.90, 95% CI 0.05–1.75) than those positioned using traditional positioning methods. No other significant differences were observed. Reduction in asymmetry among preterm infants is an important benefit of alternative positioning, as symmetrical movement and responses are crucial for early development. However, it will be important to follow this sample of preterm infants to determine the effects of early positioning on neurodevelopmental outcome in childhood.
Maximum density effects on natural convection in a porous layer differentially heated in the horizontal direction

Abstract This paper reports a fundamental study of natural convection in a fluid saturated porous layer differentially heated in the horizontal direction, when the fluid possesses a density maximum such as that of water at 3.98°C. The study is undertaken in two distinct parts. In the first part the flow and temperature fields in the porous cavity are determined theoretically on the basis of an asymptotic analysis valid in the conduction dominated low Ra regime, where Ra is the Darcy-modified Rayleigh number based on the layer height. It is shown that in this limit the circulation in the porous enclosure consists of two cells, antisymmetric about the midlength. The second part of the study is focused on a complete sequence of numerical simulations covering the ranges 100 ⩽ Ra ⩽ 1000, 0.5 ⩽ H/L ⩽ 2, 5 ⩽ T H ⩽ 7.96. The numerical solutions prove that increasing the Rayleigh number or decreasing the aspect ratio leads to the development of thermal boundary layers along the two driving walls and the midlength and enhances the role of convection on the net heat transfer across the porous layer. The bicellular flow field, which is a direct result of the existence of the density maximum associated with the temperature of T H = 3.98°C, is a feature of all the numerical simulations. However, the two cells are antisymmetric about the midlength only in the case where T H − T o = T o − T c .
On the attenuation of transient spherical waves in a four-element viscoelastic model and its implications

In a four-element model, which consists of two Voigt elements in series, the impulse responses of spherical waves for particle displacement, velocity, acceleration and strain are computed numerically. These impulse responses are shown to be useful in synthesis for the desired wave response through convolution, between the input of the source function and the impulse responses. The rate of decay of peak amplitude versus distance, as waves radiate out, is examined in the region close to the source which may be nuclear or dynamite explosives and found to be linear in log-log scale. The amplitude spectra of the unit impulse response are obtained through Fourier analysis, and the model is found to behave as a low pass filter. With the properly chosen elastic constants for springs in the model and damping coefficients for dashpot, it is seen that, like the earth materials, the attenuation exponent (in neper/1000 ft) versus frequency in the model is approximately linear. One of the results observed byCollins andLee [1] is fitted by the model. The model thus simulates more nearly the wave in earth materials close to the source than the Voigt solid.
High-throughput corrosion quantification in varied microenvironments

Abstract Harsh conditions ranging from those of biomedical implants to industrial oilfield applications prompt rapid assessment of whether and to what extent corrosion will occur. Here, we describe and demonstrate a novel high-throughput approach to quantify corrosion susceptibility based upon electrical resistance and colorimetric outputs. We illustrate this capability by quantifying aerobic corrosion rates of steel alloys within hours, and by comparing anaerobic microbiologically influenced corrosion (MIC) conditions over several days. Such methods can be extended to rapidly assess conditions that will accelerate corrosion, to compare corrosion mitigation scenarios, and to explore biofilm formation and MIC mechanisms through robust replicate conditions.
Enhanced flux pinning properties in superconducting FeSe0.5Te0.5 thin films with secondary phases

In this paper we report epitaxial superconducting FeSe0.5Te0.5 thin films grown on single crystal SrTiO3 (STO) (100) substrates by a pulse laser deposition (PLD) technique. The films include a single layer grown under vacuum, a single layer grown in controlled oxygen atmosphere and a tri-layer film with a 7 nm thick CeO2 interlayer. All the films show a similar transition temperature Tc ranging from ∼12 K () to ∼10 K (), while the CeO2 nanolayer sample shows a significantly enhanced critical current density under magnetic field. The calculated critical current density of the film with the CeO2 interlayer is ∼105A cm−2 at 2 K in self-field and 2.8 × 104 A cm−2 at 7 T at 2 K. The power-law exponent α value of the sample is determined to be as low as 0.21 at 2 K. Microstructural analysis shows that both the oxygen grown sample and the sample with the CeO2 nanolayer have uniform nanoclusters in the film matrix. These secondary phases as well as the defects around the interlayer interfaces might be responsible for the enhanced pinning properties.
Joint computational/experimental aerodynamics research on hypersonicvehicle. II - Computational results

Parabolized and iterative Navier-Stokes codes are used to predict flowfield solutions around a hypersonic vehicle. Aerodynamic force and moment predictions from the codes are compared with experimental data from the Sandia National Laboratories Mach 8 wind tunnel. The comparisons are made on a spherically blunted cone with a slice parallel to the body axis. On the slice portion of the vehicle, a flap can be attached so that deflection angles of 10, 20, and 30 deg can be obtained. The Sandia parabolized Navier-Stokes code is used to generate solutions for the sliced vehicle with no flap. For the vehicle with a flap, axially separated flow occurs, and a time iterative Navier-Stokes code is used to provide comparisons with the data. Aerodynamic force and moment comparisons are made for laminar flow, and an ideal gas is assumed in the calculations. A detailed study of grid convergence is presented to determine the accuracy of the numerical solutions. Predictions obtained from the codes show very good agreement with the experimental data for force and moment coefficients, except for large flap deflections.
The Darwinian family

Born to Rebel: Birth Order, Family Dynamics and Creative Lives. By Frank J. Sulloway. Pantheon: 1996. Pp. 653. $30.
Sleep and arousal, synchrony and independence, among mothers and infants sleeping apart and together (same bed): an experiment in evolutionary medicine

Although solitary sleeping in infancy is a very recent custom, limited to Western industrialized societies, and most contemporary people practice parent-infant co-sleeping, virtually all laboratory research on sleep in human infants assumes that solitary infant sleep is the normal and desirable environment. We have used evolutionary and developmental data to challenge this view. We suggest that co-sleeping provides a sensory-rich environment which is the more appropriate environment in which to study infant sleep. In addition, two preliminary, in-laboratory, polygraphic investigations of mother-infant co-sleeping are reported in normal infants, within the peak age range for sudden infant death syndrome (SIDS). Five mother-infant pairs co-slept one night in the first study; in the second, three additional pairs slept separately for two nights and co-slept the third consecutive night. The results suggest that co-sleeping is associated with enhanced infant arousals and striking temporal overlap (synchronicity) in infant and maternal arousals, and that, possibly as a result, co-sleeping mothers and infants spend more time in the same sleep stage or awake condition. The implications of the hypothesis and preliminary results for research on the normal development of infant sleep and on SIDS are discussed.
VARIATION IN THE PRESENCE AND CAUSE OF DENSITY‐DEPENDENT MORTALITY IN THREE SPECIES OF REEF FISHES

Determining the mechanisms by which natural populations are regulated is a key issue in ecology. Identifying the biological causes of density dependence has, however, proved difficult in many systems. In this study we tested whether adults of three species of reef fish (all gobies) suffered density-dependent mortality, and whether the density-dependent component of mortality was caused by predation. We used field experiments to test for density dependence in each prey species, manipulating the presence of predators and prey density in a factorial design. Prey were stocked on replicate patches of reef constructed of natural materials, with each reef receiving a different density of gobies. Predatory fishes were excluded from half of the reefs using a combination of removals and exclusion cages. Survival of the first species, Lythrypnus dalli, was high and density-independent on reefs free of predators, but declined rapidly with increasing density on reefs to which predators had access. Density dependence in L. dalli was thus a result of mortality inflicted by predatory fishes. In the second species, Coryphopterus nicholsii, predators caused a large reduction in the survival in one experiment but had a negligible effect in a second experiment. More importantly, though, survival of C. nicholsii was always independent of its density, regardless of predator presence. In the final species, Coryphopterus glaucofraenum, two separate experiments showed that natural changes in adult abundance (experiment 1) and survival of stocked adults (experiment 2) were density-dependent regardless of predator presence. Both experiments thus indicated that the density-dependent component of loss in C. glaucofraenum was caused, at least in part, by an interaction other than predation. The presence, intensity, and biological cause of density-dependent survival were thus strikingly different for each of these three fishes, despite the fact that they are taxonomically closely related and ecologically similar. These findings suggest a need for further studies aimed at predicting under what circumstances different mechanisms of population regulation will operate.
Concurrent measurements of directional reflectance and temperature of a wintertime coniferous forest from space

We measure directional reflectance and daytime temperature of a wintertime coniferous forest from space using data acquired by the Department of Energy's Multispectral Thermal Imager (MTI). The study site is the Howland experimental forest in central Maine. The data include measurements from all seasons over a one-year period from 2001-2002 but with a concentration in late winter and early spring. The results show variation in both reflectance and temperature with direction and season. The reflectance results compare favorably with previous bidirectional measurements performed at the Howland site. Near-nadir reflectance in the visible bands varies periodically over the year with a high in summer and a low in winter. Near-infrared (NIR) reflectance shows dual variation. The canopy reflectance varies as a function of solar and satellite zenith angle, presumably due to a changing proportion of shadows. Furthermore, a NIR pseudo-BRDF (bidirectional reflectance distribution function) shows that the canopy brightens in the NIR during fall and winter. Retrieved canopy temperatures are consistently warmer in the off-nadir view by about 2°C, with a small seasonal variation. The seasonal canopy temperature trend is well exhibited, and days with snow on the ground are easily distinguished from days with no snow on the ground. The results also show that the retrieved temperatures are consistently warmer than above-canopy air temperature by about 4°C. This difference is greater for off-nadir views and also appears to be larger in the spring and summer than in the fall and winter.
Menopausal experiences and bone density of Mayan women in Yucatan, Mexico.

This cross-sectional study reports on the menopausal transition of Mayan women from Yucatan, Mexico. A total of 228 women completed the study, and 118 women were classified by history as postmenopausal; the others were premenopausal. Demographic information, reproductive history, physical examination, hormone concentrations, radial bone density, food samples, and history of physical activity were obtained. The average age at which menopause occurred by history was 44.3 +/- 4.4 years; this is reflected in the distribution of FSH levels by age. None of the women reported symptoms of hot flashes, and none recalled any history of significant symptoms associated with their menopausal transition. Hormone levels were similar to U.S. reference values with elevated FSH (66.6 +/- 29.1 mIU/ml), low estradiol (9.4 +/- 8.3 pg/ml) and estrone (13.3 +/- 7.8 pg/ml), E1 > E2, and normal levels of testosterone and androstenedione. BMD declined with age, and values were lower than reference values for United States women. Clinical evidence of fracture was not detected by history or physical examination even for those who were 20 years postmenopausal. The endocrine characteristics of menopause among Mayan women in Yucatan are similar to hormonal changes reported for women in the United States, but signs, symptoms, and apparent consequences are different in the two populations.
Morphometrics of Daucus (Apiaceae): A counterpart to a phylogenomic study

PREMISE OF STUDY Molecular phylogenetics of genome-scale data sets (phylogenomics) often produces phylogenetic trees with unprecedented resolution. A companion phylogenomics analysis of Daucus using 94 conserved nuclear orthologs supported many of the traditional species but showed unexpected results that require morphological analyses to help interpret them in a practical taxonomic context. METHODS We evaluated character state distributions, stepwise discriminant analyses, canonical variate analyses, and hierarchical cluster analyses from 40 morphological characters from 81 accessions of 14 taxa of Daucus and eight species in related genera in an experimental plot. KEY RESULTS Most characters showed tremendous variation with character state overlap across many taxa. Multivariate analyses separated the outgroup taxa easily from the Daucus ingroup. Concordant with molecular analyses, most species form phenetic groups, except the same taxa that are problematical in the molecular results: (1) the subspecies of D. carota, (2) D. sahariensis and D. syrticus, and (3) D. broteri and D. guttatus. CONCLUSIONS Phenetic analyses, in combination with molecular data, support many Daucus species, but mostly by overlapping ranges of size and meristic variation. The subspecies of D. carota are poorly separated morphologically, are paraphyletic, and all could be recognized at the subspecies rank under D. carota. Daucus sahariensis and D. syrticus are so similar morphologically that they could be placed in synonymy. Combined molecular and morphological data support three species in accessions previously identified as D. broteri and D. guttatus. Molecular and morphological results support the new combination Daucus carota subsp. capillifolius.
Agent-based artificial immune system approach for adaptive damage detection in monitoring networks

This paper presents an agent-based artificial immune system approach for adaptive damage detection in distributed monitoring networks. The presented approach establishes a new monitoring paradigm by embodying desirable immune attributes, such as adaptation, immune pattern recognition, and self-organization, into monitoring networks. In the artificial immune system-based paradigm, a group of autonomous mobile monitoring agents mimic immune cells (such as B-cells) in the natural immune system, interact locally with monitoring environment, and respond to emerging problems through simulated immune responses. The presented immune-inspired monitoring paradigm has been applied to structural health monitoring. The ''antibody'' of a mobile monitoring agent is a pattern recognition algorithm tuned to a certain type of structural damage pattern. The mobile monitoring agent performs damage diagnosis based on structural dynamic response data. Mobile monitoring agents communicate with each other and collaborate with network components based on agent interaction protocols defined in agent standards, the Foundation for Intelligent Physical Agents standards. A mobile agent system embedded in sensor nodes supports the selective generation, migration, communication, and management of mobile monitoring agents automatically. The active structural health monitoring is achieved by distributing mobile monitoring agents to the sites where they are needed. The structural damage diagnosis using mobile monitoring agents and artificial immune pattern recognition method has been tested using a scaled steel bridge structure. The test result shows the feasibility of using this approach for real-time structural damage diagnosis.
La imaginación literaria en la vida pública

La literatura y la imaginacion literaria pueden tener un efecto subversivo frente a la idea de racionalidad expresada habitualmente por la ciencia economica utilitarista. Por ello, la literatura debe formar parte de una educacion en favor de una idea de racionalidad publica mas amplia que la idea de individuo como maximizador de utilidades. A traves del analisis de la novela de Dickens Tiempos dificiles, se llega a la conclusion de que solo la imaginacion proporcionada por las novelas -y no por los libros de economia politica- puede ser la base para gobernar adecuadamente un pais de personas libres e iguales o para desarrollar nuestra vida cotidiana como ciudadanos
Failure of serial human immunodeficiency virus type 1 DNA polymerase chain reactions to identify human immunodeficiency virus type 1 clade A/G.

AbstractThe most commonly used test to screen for human immunodeficiency virus type 1 (HIV-1) infection in HIV-exposed infants in the United States is HIV-1 qualitative DNA polymerase chain reaction (PCR). However, the commercially available HIV-1 DNA PCR lack optimal sensitivity to detect non-subty