cssi/SciSciGPT-SciSciNet huggingface dataset:
Time-Dependent Modeling of Brillouin Scattering in Optical Fibers Excited by a Chirped Diode Laser

Numerical simulations are used to solve the coupled partial differential equations describing stimulated Brillouin scattering (SBS) built up from random thermal phonons as a function of time and the longitudinal spatial coordinate in an optical fiber. In the case of a passive fiber, a laser beam is incident with constant power, but its frequency is linearly ramped at 1.55 μm at a rate of up to 1016 Hz/s. High chirp rates lead to an increased Brillouin spectral bandwidth and decreased gain. The resulting SBS suppression is well described by an adiabatic model and agrees with experimental results. For an 18-m active fiber pumped at 1.06 μm and chirped at up to 2 × 1016 Hz/s, the suppression enables output laser powers in the kilowatt range while maintaining a narrow instantaneous linewidth.
Nonreflecting boundary conditions for linearized unsteady aerodynamic calculations

The present method for the implementation of nonreflecting boundary conditions in 2D and 3D linearized unsteady flow computations is applied to cases of unsteady flows in turbomachine blade rows. The eigenmodes of a discrete representation of the governing equations are computed and used to construct nonreflecting boundary conditions. In 3D, a mixed numerical method is used; in 2D, the discrete representation of the governing equations is obtained from the discretized equations used by the flow solver itself. Wavenumbers and radial mode shapes are computed.
Abraham Wald's Work on Aircraft Survivability

Abstract While he was a member of the Statistical Research Group (SRG), Abraham Wald worked on the problem of estimating the vulnerability of aircraft, using data obtained from survivors. This work was published as a series of SRG memoranda and was used in World War II and in the wars in Korea and Vietnam. The memoranda were recently reissued by the Center for Naval Analyses. This article is a condensation and exposition of Wald's work, in which his ideas and methods are described. In the final section, his main results are reexamined in the light of classical statistical theory and more recent work.
It's the amount of thought that counts: when ambivalence contributes to mammography screening delay.

Abstract Purpose This study examines whether ambivalence toward mammography screening, as moderated by total amount of thought given to the reasons for and against getting mammograms at recommended intervals, predicts greater delay in obtaining subsequent screening mammograms. Methods A sample of 3,430 insured women with recent (within the last 8–9 months) screening mammograms completed telephone interviews as part of a 5-year intervention study to achieve sustained adherence to annual-interval mammography. Delay was assessed by the number of days between mammograms. Results Controlling for demographic factors and perceived screening barriers, days between mammograms increased as ambivalence and thought increased. Thought moderated ambivalence: Among women who were most ambivalent, women obtained mammograms 1 month earlier for each unit increase in thought. Conclusion Future studies should test innovative ways to resolve ambivalence and increase thought about consequences of getting mammograms as a strategy to promote mammography screening adherence.
Fiber-optic links based on silicon photonics for high-speed readout of trackers

We propose to use silicon photonics technology to build radiation-hard fiber-optic links for high-bandwidth readout of tracking detectors. The CMOS integrated silicon photonics was developed by Luxtera and commercialized by Molex. The commercial off-the-shelf (COTS) fiber-optic links feature moderate radiation tolerance insufficient for trackers. A transceiver contains four RX and four TX channels operating at 10 Gbps each. The next generation will likely operate at 25 Gbps per channel. The approach uses a standard CMOS process and single-mode fibers, providing low power consumption and good scalability and reliability.
Common variable immunodeficiency.

Common variable immunodeficiency (CVID) is a common primary immnodeficiency disease, the hallmark of which is hypogammaglobulinemia. Due to the lack of antibodies, patients usually have recurrent bacterial infections, but there are a number of other puzzling manifestations, including inflammatory conditions, autoimmune disease, and the development of lymphomas. Most patients are diagnosed as adults, and delay in the recognition of the antibody defect is comon. A number of defects of T cell function and deficits in the memory B cell pool have been identified, but the underlying cause of this defect remains unknown.
The multi-dimensional approach to linguistic analyses of genre variation: An overview of methodology and findings

The present paper summarizes the major methods and results of the multi-dimensional approach to genre variation. The approach combines the resources of computational tools, large text corpora, and multivariate statistical tools (such as factor analysis and cluster analysis). It has been used to address issues such as the relations among spoken and written genres in English, and the historical development of genres and styles. The approach has also been applied to other languages; in this regard it has been used to address broader theoretical issues, such as the extent to which genre, and style variation are comparable cross-linguistically, and the linguistic consequences of literacy.
Stabilizability of linear systems defined over C * -algebras

LetF andG be elements of aC *-algebraA. Assume that, for each irreducible*-representationπ ofA on a Hilbert space210B; π , there is a bounded linear operatorL π ∈B(ℋ π ) such that the spectrum ofπ(F) −π(G)L π is contained in the open left half plane. We prove that there is then an elementL ∈A such that the spectrum ofF — GL is contained in the open left half plane. That is, if the system (F, G) is locally stabilizable, then it is stabilizable. We also consider the analogous problem with the open left half plane replaced by the open unit disk.
The impact of obesity on health care costs among persons with schizophrenia.

Abstract Background Obesity is the second leading cause of preventable death in the United States and is twice as common among individuals with schizophrenia as the general population. Methods Data from the Clinical Antipsychotic Trials of Intervention Effectiveness, a multisite trial of antipsychotic pharmacotherapy in 1460 patients with schizophrenia, were used to examine the relationships between body mass index (BMI) and medical costs. Results ANCOVA analyses found significant increases in both psychiatric and nonpsychiatric medication costs associated with increasing BMI and a significant, but smaller, difference in costs of outpatient medical–surgical service utilization: US$41 per month for morbidly obese patients compared to US$26 per month for patients of normal weight ( F =2.4, P =.04). In multivariable logistic regression analyses, morbid obesity was associated with significantly increased odds of any outpatient medical–surgical service costs. When compared to observations of BMI>35, BMI observations within the normal range (18.5–24.9) were half as likely to be associated with any outpatient medical–surgical costs (OR=0.53; 95% CI=0.45, 0.63). Conclusions In this large sample of persons with schizophrenia, obesity was associated with increased outpatient general medical service and medication costs even after controlling for demographic characteristics and medical comorbidity, but the absolute dollar amount was small.
Visual search in medical images: a new methodology to quantify saliency

The quantification of object saliency in 2D grayscale images is of primary importance in medical imaging. Saliency, in this paper, refers to the detectability of objects of unknown location, an object being a feature of interest in an image. Object saliency is commonly measured by the speed of an observer at performing a detection task. The more salient an object is, the more quickly it can be detected. The questions raised in this paper are (1) whether the degree of saliency of an object can be solely predicted from its detectability as measured in a location know-exactly task, or whether factors such as geometry and context contribute to saliency in a more complex fashion and (2) whether the contribution of geometry and background complexity to saliency can be quantified. This paper focuses on the problem of detection of stenoses in simulated angiograms. Results from a first such study are presented. From those results a new general methodology to measure saliency in 2D grayscale images was inferred and is presented.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Solutions of the shallow water equations on a sphere

Abstract Various numerical solutions of the shallow water equations in two dimensions are studied in an effort to develop a computational technique applicable to hydrodynamics in spherical geometry. The equations are first cast in a form which allows periodic boundary conditions in both angular coordinates. Explicit numerical solutions using leap-frog centered differencing in time and either second, fourth, or compact fourth order centered spatial differencing are studied. The fourth order compact differencing is found to be easily adapted to spherical geometry and is superior to the second order technique. We also consider an alternating-direction implicit (ADI) scheme in an attempt to increase computational efficiency by taking larger time steps. Both analytically steady state and time dependent solutions are examined to investigate stability properties and discretization errors in time and space. Implicit methods require more computation per time step than explicit methods for solution of the shallow water equations. However, the total time for a simulation can be less with the implicit method. The ADI formalism also has advantages of importance for more physically complex problems.
Baryon-Antibaryon Phase Transition at High Temperature

Present experimental data on nucleon-antinucleon scattering allow a study of the possibility of a phase transition in a nucleon-antinucleon gas at high temperature. Estimates can be made of the general behavior of the elastic phase shifts without resorting to theoretical derivation. A phase transition which separates nucleons from antinucleons is found at about 280 MeV in the approximation of the second virial coefficient to the free energy of the gas. A rigorous treatment of the contribution of the inelastic channels remains, however, a difficulty.
Segmentation of 830- and 1310-nm LASIK corneal optical coherence tomography images

Optical coherence tomography (OCT) provides a non-contact and non-invasive means to visualize the corneal anatomy at micron scale resolution. We obtained corneal images from an arc-scanning (converging) OCT system operating at a wavelength of 830nm and a fan-shaped-scanning high-speed OCT system with an operating wavelength of 1310nm. Different scan protocols (arc/fan) and data acquisition rates, as well as wavelength dependent bio-tissue backscatter contrast and optical absorption, make the images acquired using the two systems different. We developed image-processing algorithms to automatically detect the air-tear interface, epithelium-Bowman's layer interface, laser in-situ keratomileusis (LASIK) flap interface, and the cornea-aqueous interface in both kinds of images. The overall segmentation scheme for 830nm and 1310nm OCT images was similar, although different strategies were adopted for specific processing approaches. Ultrasound pachymetry measurements of the corneal thickness and Placido-ring based corneal topography measurements of the corneal curvature were made on the same day as the OCT examination. Anterior/posterior corneal surface curvature measurement with OCT was also investigated. Results showed that automated segmentation of OCT images could evaluate anatomic outcome of LASIK surgery.
Probability and delay of reinforcement: an examination of Mazur's equivalence rule.

It has recently been proposed that the probability of an event (e.g. delivery of a reinforcer) can be interpreted as functionally equivalent to the delay of an event. The present experiment examined the equivalence rule that states that reinforcer probability is functionally equivalent to a set of variable delays. A titration procedure was used in which pigeons chose between a standard, probabilistic alternative, and an adjusting, delayed alternative. Reinforcer probability was manipulated by varying the number of keypecks required to obtain a reinforcer. The duration of the adjusting alternative varied as a function of a pigeon's previous choices. There were six standard probabilities. The results indicated that the pigeons were sensitive to changes in the standard probabilities and that there were significant relations between: (1) reinforcer probability and the mean adjusted delay of reinforcement, and (2) the obtained and predicted adjusted delays. The present results support Mazur's conception of the relation between reinforcer probability and delay, and extend his conception to a different method of manipulating reinforcer probability.
Report From the Cardiovascular and Renal Drugs Advisory Committee US Food and Drug Administration; June 15–16, 2005; Gaithersburg, Md

The Advisory Committee was asked to consider the desirability of class labeling for antihypertensive drugs. Antihypertensive drugs, with few exceptions, have no clinical outcomes claims in their labeling because approval of these agents is usually based on demonstration of efficacy at lowering blood pressure, not reducing morbidity or mortality. Initial placebo-controlled trials of antihypertensive agents were conducted more than 2 decades ago. Accordingly, it has been considered ethically inappropriate to perform placebo-controlled studies of modern antihypertensive agents. These factors have resulted in a clinical conundrum in which agents believed to be highly effective at reducing morbidity and/or mortality cannot claim such benefits. The Advisory Committee meeting was convened to consider how labeling should address the relationship between blood pressure and outcome. The committee felt strongly that not having outcome data available in antihypertensive drugs labels prevents optimal education of practitioners regarding the benefits of important therapeutic agents. Several committee members pointed out that undertreatment of blood pressure remains a major health problem that might be addressed by more descriptive class labeling of antihypertensive agents. The committee agreed that scientific knowledge about antihypertensive drugs is extensive and that lowering blood pressure represents one of the best-studied surrogate outcome measures in clinical medicine. However, the committee expressed some concern regarding “unintended consequences” of class labeling and discussed the need for robust preapproval safety studies and postmarketing surveillance. The industry representative on the committee cautioned that class labeling might represent a disincentive to the pharmaceutical industry to engage in future clinical trials. The committee reviewed the effects of blood pressure reduction on specific cardiovascular and renal outcome measures. After considerable discussion, the committee agreed that reduction in the incidence of stroke and myocardial infarction is the most clearly attributable benefits of blood pressure reduction. Evidence for reduction in cardiovascular mortality and renal disease …
Entanglements of an End-Grafted Polymer Brush in a Polymeric Matrix

We analyze the entanglement of polymer brushes embedded in long-chain melts and in good and ϑ solvents. Individual entanglements are identified using a modified version of primitive path analysis. Due to entropic collapse, the brushes embedded in the melt are more self-entangled than those in the implicit solvents. The self-entanglement of the brushes in the good and ϑ solvents as a function of coverage follows a simple scaling argument. We observe a depletion of entanglements near the systems' confining walls and offer several possible explanations. In the melt-embedded systems, the brushes entangle predominantly with the melt at low coverage and with themselves at high coverage. The peak of the brush−melt entanglement density is highest at an intermediate coverage, but the integrated areal brush−melt entanglement density continues to increase with coverage for the studied systems. This areal density correlates well with earlier measurements of the work of adhesion.
n-butane isomerization catalyzed by supported aluminum chloride

Abstract Solid superacid catalysts were prepared by the reaction of aluminum chloride vapors with each of the following supports: (i) silica, (ii) sulfated silica, (iii) sulfonated silica, and (iv) sulfonated macroporous poly(styrene-divinylbenzene). The resulting solids catalyzed the isomerization of n-butane at 0.1–1 atm and 23–140 °C, the rate being of the order of 10−4 molecules/(Al atom · s) at 100 °C for the polymer-supported catalyst. HCl in the feed to a flow reactor increased the rate of the catalytic reaction. The n-butane isomerization was described by Langmuir-Hinshelwood kinetics, the reaction being first order in the concentration of adsorbed reactant. The superacidic catalytic sites (of undetermined structure) were formed by the combination of aluminum chloride with Bronsted acid groups.
Prebiotic formation of cytidine nucleotides.

IN contrast to the plausible explanations for proteinoid formation1, there seems to be no satisfactory concept for the genesis of polynucleotide templates in the presumed conditions of the primitive Earth. Only parts of the problem, such as the origin of the bases2,3 and carbohydrates4 and the synthesis of short oligonucleotides5,6, have been subjected to informative experiment. A working hypothesis of the past decade took for granted the availability of common nucleosides, but only in 1970 was a plausible, though inefficient, route to any natural nucleosides proposed7. Some recent evidence suggests, however, that natural nucleosides need not be direct precursors of the corresponding nucleotides and polynucleotides.
Sexual assertiveness in low-income African American women: unwanted sex, survival, and HIV risk.

The objective of this study was to determine the relationship of social variables related to sexual relationships in African American women.1 The study used a quantitative descriptive design to gather data from a convenience sample of 524 African American women aged 18 to 49 who dwelled in the southeastern United States. The study utilized the HIV Risk Behavior Questionnaire to determine the participant's level of HIV risk. Results indicated substantial levels of sex in the women due to violence or fear of violence, relationship loss, lost shelter, and high levels of unwanted sex. There was a positive correlation between level of survival sex and high-risk behavior (R = .651, p < .01). Multiple correlations indicated associations between history of forced sex and sex due to fear of violence (R = .604, p < .01). Further correlations indicated a pattern of association between poverty, age, and sex out of fear of relationship loss or shelter loss. The study indicates a need for a broader definition of HIV-re...
Predicting Weight Loss From Smoldering Combustion in Cellulosic Insulation

A mathematical model was developed which predicted the weight loss that would occur under smoldering conditions when the test was conducted according to Federal Specification HH-I-515D. Also a smoldering propagation parameter was identified that was sensitive to various treat ment levels.
Erythrocyte acetylcholinesterase and glucose-6-phosphate dehydrogenase in newborn infants of low birth weight

Abstract Red cell acetylcholinesterase (EC 3.1.1.7) activity is subnormal in ABO hemolytic disease of the newborn. Since this disorder also occurs in infants of low birth weight and inasmuch as the specific activity of several red cell enzymes is lower in these infants than in fullterm babies, acetylcholinesterase activity was determined within the second day of life in 120 newborn infants of low birth weight. Enzyme activity was lower in these infants than in normal full-term newborns, but significantly higher than in infants affected with ABO hemolytic disease of the newborn. The measurement of glucose-6-phosphate dehydrogenase (EC 1.1.1.49), a sexlinked enzyme of importance in drug-induced hemolytic anemias and implicated in neonatal jaundice in certain populations, showed no differences in activity between infants of low birth weight and full-term infants.
Large-system usage of fiber channel standard

Current and emerging high-speed applications and environments create new and challenging requirements for high-speed channels on large systems. The Fiber Channel Standard (FCS) defines transmission and signalling protocols that allow various Upper Level Protocols (for example, IPI3 and IP) to be transported over a variety of physical interfaces. This rich set of function allow FCS to address many aspects and varieties of high-speed interconnect, by permitting a variety of implementations, based on trade-offs of cost, performance objectives, implementation complexity, and recoverability. The current presentation describes several high-speed applications and environments and the usage of FCS channels by large systems in those environments. Application of various FCS functions and features to this large system environment are discussed.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Development of a bioartificial pancreas: I. Long-term propagation and basal and induced secretion from entrapped βTC3 cell cultures

Bioartificial pancreatic constructs based on immunoisolated, insulin-secreting cells have the potential for providing effective, long-term treatment of type I (insulin-dependent) diabetes. Use of insulinoma cells, which can be amplified in culture, relaxes the tissue availability limitation that exists with normal pancreatic islet transplantations. We have adopted mouse insulinoma βTC3 cells entrapped in calcium alginate/poly-L-lysine/alginate (APA) beads as our model system for a bioartificial pancreas, and we have characterized the effects of long-term propagation and of glucose concentration step changes on the bioenergetic status and on the metabolic and secretory activities of the entrapped cells. Cell bioenergetics were evaluated nonivasively by phosphorus-31 nuclear magnetic resonance (31P NMR) spectroscopy, and metabolic and secretory parameters by assaying cell culture medium. Data indicate that net cell growth occurred between days 3 and 10 of the experiment, resulting in an approximate doubling of the overall metabolic and secretory rates and of the intracellular metabolite levels. Concurrently, a reorganization of cell distribution within the beads was observed. Following this growth period, the measured metabolic and secretory parameters remained constant with time. During glucose step changes in the perfusion medium from a high concentration of 12 to 15 mM to 0 mM for 4.5 h to the same high glucose concentration, the oxygen consumption rate was not affected, whereas insulin secretion was always glucose-responsive. Intracellular nucleotide triphosphates did not change during 0 mM glucose episodes performed early in culture history, but they declined by 20% during episodes performed later in the experiment. It is concluded that the system of APA-entrapped βTC3 cells exhibits several of the desirable characteristics of a bioartificial pancreas device, and that a correlation between ATP and the rate of insulin secretion from βTC3 cells exists for only a domain of culture conditions. These findings have significant implications in tissue engineering a long-term functional bioartificial endocrine pancreas, in developing noninvasive methods for assessing construct function postimplantation, and in the biochemical processes associated with insulin secretion. © 1999 John Wiley & Sons, Inc. Biotechnol Bioeng 66: 219–230, 1999.
DVLASIC: catastrophic fault yield simulation in a distributed processing environment

Simulation of local process disturbances is a computationally intensive task. The VLASIC (VLSI LAyout Simulation for Integrated Circuits) catastrophic-fault yield simulator uses a Monte Carlo method that often requires tens of CPU hours to perform a simulation. In order to reduce the simulation time, DVLASIC, the distributed-environment version developed by the authors, achieves a speedup of 13.3 over VLASIC, with an efficiency of 89%. The authors describe the distributed processing environment and implementation techniques used to obtain this speedup. The distributed processing environment can also be applied to many other CAD problems. >
Disruption of the bottom log layer in large-eddy simulations of full-depth Langmuir circulation

We report on disruption of the log layer in the resolved bottom boundary layer in large-eddy simulations (LES) of full-depth Langmuir circulation (LC) in a wind-driven shear current in neutrally-stratified shallow water. LC consists of parallel counter-rotating vortices that are aligned roughly in the direction of the wind and are generated by the interaction of the wind-driven shear with the Stokes drift velocity induced by surface gravity waves. The disruption is analysed in terms of mean velocity, budgets of turbulent kinetic energy (TKE) and budgets of TKE components. For example, in terms of mean velocity, the mixing due to LC induces a large wake region eroding the classical log-law profile within the range . The dependence of this disruption on wind and wave forcing conditions is investigated. Results indicate that the amount of disruption is primarily determined by the wavelength of the surface waves generating LC. These results have important implications for turbulence parameterizations for Reynolds-averaged Navier–Stokes simulations of the coastal ocean.
The Food Economy and French Colonial Rule in Central Cameroun

French administrative policies during the inter-war period in Central Cameroun created a class of indigenous chiefs who fulfilled crucial functions in the mobilization of manpower and resources from the rural areas for the development of the European sector of the economy. Early problems in organizing food markets to provision the growing non-agricultural sector resulted in a decision to channel agricultural growth through the chiefs rather than to leave it to market forces. The institution of a food requisition system involved the administration in exercising direct control over key aspects of the rural economy through the regulation of production, price control, control of the trading network, and the use of the indigenat to support the rights of chiefs over their subjects. The system succeeded in achieving two purposes at once: it guaranteed a cheap, reliable supply of food to the wage-earning population, thus allowing wages to remain low and stable; and it encouraged the development of a class of wealthy planters in the rural areas whose self-interest lay in support for the colonial administration. However, close control of the economy became impossible in the late 1930s, and the government's dissatisfaction with some of the implications of its own chieftaincy policy resulted in the abandonment of the whole inter-war system. The rural economy which gradually emerged after 1946 was characterized by family-based production units but lacked a well-developed institutional framework appropriate to it.
Fiber optics based ion discriminator

Radiation detector capable of discriminating between different species of high energy ions is of great demand by aerospace and high energy physics communities. We propose the optical fiber-based real time ion detector and discriminator, which can have long lifetime in radiation environment, can be compact and low production cost. The basis of detector's principle of operation is the strong dependence of the pattern of energy dissipation with ion penetration depth in the matter on the type of the ion. Another key phenomenon enabling our fiber optic based detector is the refractive index change in optical fiber in the vicinity of particle track due to the dissipated energy. These two effects provide the opportunity to measure the energy dissipation versus penetration depth as well as total energy released simultaneously in real time with a single detector. Thus, different types of ions can be distinguished by measuring total energy dissipated and energy dissipation versus distance. To discriminate between ions species we propose to use measurement of the Bragg peak position. Total energy dissipated by the particle in the detector material and determination of the Bragg peak position gives the full information on the kind of the incident ion as confirmed via simulations.
Acceptance of moderate drinking by alcoholism treatment services in Canada.

Objective: The present study was conducted to provide a nationwide survey of acceptance of nonabstinence goals and related alcoholism treatment practices by Canadian alcoholism treatment services. Method: A random sample of 335 Canadian alcoholism treatment service agencies were mailed a 4-page questionnaire designed to assess acceptance of moderate drinking as a drinking goal and related alcoholism treatment practices. Results: Acceptance varied by type of service, with considerably more acceptance by outpatient programs (62%) and mixed inpatient/outpatient programs (43%) than inpatient/detoxification/ correctional facilities (27%) and halfway houses (16%). Two-thirds of the respondents who reported moderate drinking as unacceptable in their own agencies categorically rejected moderation for all alcoholism clients. Conclusions: Individuals seeking services in Canadian alcoholism treatment agencies are more likely to have a choice of drinking goals if they present to an outpatient program than a residenti...
Hemodynamic effect of Neuroform stent on intimal hyperplasia and thrombus formation in a carotid aneurysm.

Stents play an important role in management of cerebral aneurysms. A stent reconstructs the parent artery, assists coil embolization, and decreases flow activity within an aneurysm. However, an in-stent stenosis often occurs within the stented artery and compromises the circulation at the parent artery. Hemodynamic basis of re-stenoses from aneurysm stenting is not fully understood. An 8 mm cavernous carotid aneurysm with a wide neck was treated by a Neuroform stent first and by coils five weeks later. A comparison of the difference in morphology during this five-week period reveals the presence of inti- mal hyperplasia in the internal carotid artery, 1.3 mm thick at the proximal end and 1 mm at the distal end of the stent, and 1 mm thick thrombus at the postero-inferior side of the aneurysm. Computational fluid dynamic analyses show that the site of intimal hyperplasia is exposed to low wall shear with high oscillatory shear index (OSI), and the location of thrombus is subject to high OSI. Intimal hyperplasia and thrombus occur at comparable rates, but at different hemodynamic conditions; however, both prefer regions with high OSIs.
Fertility, Time Use, and Economic Development

Abstract This research develops a model that incorporates both parental altruism toward children and the allocation of time among human capital investment and production in market and nonmarket sectors. By introducing these two production sectors, the model captures the interaction among fertility, human capital investment, and time use as economies grow. The model is calibrated to the World Bank's 1985 Living Standard Survey for Peru. Simulations indicate that the model explains the transition from a low-human-capital and high-fertility economy to an economy characterized by high human capital and low fertility. Journal of Economic Literature Classification Numbers: O11, J22, J24, O40.
A framework for the contextual analysis of technology-based learning environments

THE NEED FOR A FRAMEWORK to distinguish the conditions under which different types of educational computing environments are productive is addressed, and a cognitively based Contextual Analysis Framework is proposed that consists of two primary elements: (a)conceptual characteristics of the knowledge domain being learned, including thecomplexity of the concepts and tasks and the degree oforderly and regular conceptual structure of the knowledge domain; and (b)stage of learning (novice, advanced) of the learner within the knowledge domain. The characteristics of different types of technology-based learning environments (e.g., computer-based drill, intelligent tutoring systems, hypertext) are analyzed in terms of the Contextual Analysis Framework. It is argued that the failure to consider important contextual elements of learning related to conceptual characteristics of the domain and the stage of the learner could result in otherwise well-designed instructional computing technologies being used in inappropriate learning situations.
Scanning electron microscopy of the bullfrog's retina and pigment epithelium.

The retina and pigment epithelium of the bullfrog (Rana catesbiana) were studied with the scanning electron microscope. Fixed-dehydrated tissues were critical point dried with CO2, then cracked in the plane of the long axis of the photoreceptors. The cellular layers of the retina and the lateral surfaces of pigment epithelial cells were visualized. The four major types of frog photoreceptor were identified: red rod, green rod, single cone, and double cone. Cone myoids were observed to be contracted in light-adapted retinas and elongated in more dark adapted retinas.
Admissible Discriminant Analysis

Abstract Since it is usually impossible to determine a “best” discriminant analysis, admissible discriminant analyses are suggested. Let A denote some property which should be satisfied by any reasonable procedure either in general or when used in a special application. Any procedure which satisifies A is called A-admissible. Seven admissibility conditions are defined and ten discriminant algorithms are compared with them.
A novel bearing swivel joint and a universal joint for concrete pull-off testing using a material testing machine

The overall goal of this short study was to integrate two pull-off coupling devices for concrete: a bearing swivel joint and a universal joint, into an existing material testing machine. Their performance was evaluated in terms of efficiency using setup duration and compared to that of a commercially available portable testing device. Fifty-three pull-off tests were conducted on concrete prisms in accordance with ASTM C1583-04. Our results indicate that the portable tester was most efficient (6 min/test), followed by the universal joint (16 min/test), and then the bearing swivel joint (22 min/test). An online movie, as referenced in the text, demonstrates the modified test procedure, and recommendations for improvements to the test method are briefly discussed. Future testing will evaluate the variability among test results from the three devices.
THE DESIGN AND DELIVERY OF CREW RESOURCE MANAGEMENT TRAINING: EXPLOITING AVAILABLE RESOURCES

Despite widespread acceptance throughout commercial and military settings, crew resource management (CRM) training programs have not escaped doubts about their effectiveness. The current state of CRM training is an example of how an entire body of pertinent research and development has not had the impact on practice that it could. In this paper we outline additional resources (i.e., principles, information, findings, and guidelines) from the team training and training effectiveness research literatures that can be used to improve the design and delivery of CRM training. Some of the resources discussed include knowledge about training effectiveness, training teamwork-related skills, scenario design, and performance measurement. We conclude with a discussion of emerging resources as well as those that need to be developed. The purpose of this paper is to provide the CRM training developer with better access to resources that can be applied to the design and delivery of CRM training programs.
Focus Issue: An Expanding World for TGF-β Signaling

The complexity of the signaling network that is initiated by members of the transforming growth factor-beta (TGF-beta) superfamily continues to increase. In addition, Smads, which were originally identified as key transducers of TGF-beta signals, are beginning to emerge as players in other TGF-beta-independent processes. Perspectives in this issue, as well as highlights from a recent meeting on TGF-beta and select resources from the Archives, spotlight this emerging complexity.
Grieving for a Lost Network: Collective Action in a Wired Suburb

Critics have argued that information and communication technologies (ICTs) disconnect people from their social networks and reduce public participation. Research in support of this perspective has been biased by two assumptions. The first is a tendency to privilege the Internet as a social system removed from the other ways people communicate. The second is a tendency to favor broadly supportive strong social ties. Survey and ethnographic observations from Netville, a 2-year community networking experiment, suggest that weak, not strong ties experience growth as a result of ICTs. By examining a unique and underexplored stage in the life cycle of a community networking project, the end of a networking trial, this article demonstrates how ICTs facilitate community participation and collective action (a) by creating large, dense networks of relatively weak social ties and (b) through the use of ICTs as an organizing tool.
Factors associated with low bone density in patients referred for assessment of bone health

Background: To identify factors that predict low bone mineral density (BMD) in pediatric patients referred for dual-energy x-ray absorptiometry assessments. Methods: This is a retrospective cohort study of 304 children and adolescents referred for dual-energy x-ray absorptiometry assessments at a tertiary care center. Outcomes included risk factors which predicted a significant low bone density for age, defined as BMD Z-score ≤-2.0 SD. A univariate analysis involved Chi-square, Fisher’s Exact test, and analysis of variance, and multivariate logistic regression models were constructed to determine predictors of low bone mineral density. Results: In the multivariate logistic regression model, predictors of low bone mineral density included low body mass index Z-score (odds ratio 0.52, 95% confidence interval 0.39 – 0.69), low height Z-score (OR 0.71, 95% CI 0.57 – 0.88), vitamin D insufficiency (OR 3.97, 95% CI 2.08 – 7.59), and history of bone marrow transplant (OR 5.78, 95% CI 1.00 – 33.45). Conclusions: Underlying health problems and associated treatments can impair bone mineral accrual. We identified risk factors most predictive of low bone mineral density in subjects referred for bone density measurement. Recognition of these factors may allow for earlier assessment to maximize bone mass in at-risk children.
Specifying symbol instances

This paper reviews and compares the uses of dimensioning in the instance and dimensioning in the master to specify instances of symbol definitions in general-purpose graphics programming languages. The processing required to each case is described and compared. Dimensioning in the master is easier to implement, can allow faster display of images because of simpler processing, and semantically is a bit less powerful than dimensioning in the instance. When appropriate, both can gracefully coexist in a graphics language, but the great majority of graphics applications only need the semantic power of dimensioning in the master.
Influence of kynurenine 3-monooxygenase (KMO) gene polymorphism on cognitive function in schizophrenia ☆ ☆☆

Abstract Background Cognitive deficits compromise quality of life and productivity for individuals with schizophrenia and have no effective treatments. Preclinical data point to the kynurenine pathway of tryptophan metabolism as a potential target for pro-cognitive drug development. We have previously demonstrated association of a kynurenine 3-monooxygenase (KMO) gene variant with reduced KMO gene expression in postmortem schizophrenia cortex, and neurocognitive endophenotypic deficits in a clinical sample. KMO encodes kynurenine 3-monooxygenase (KMO), the rate-limiting microglial enzyme of cortical kynurenine metabolism. Aberration of the KMO gene might be the proximal cause of impaired cortical kynurenine metabolism observed in schizophrenia. However, the relationship between KMO variation and cognitive function in schizophrenia is unknown. This study examined the effects of the KMO rs2275163C>T C (risk) allele on cognitive function in schizophrenia. Methods We examined the association of KMO polymorphisms with general neuropsychological performance and P50 gating in a sample of 150 schizophrenia and 95 healthy controls. Results Consistent with our original report, the KMO rs2275163C>T C (risk) allele was associated with deficits in general neuropsychological performance, and this effect was more marked in schizophrenia compared with controls. Additionally, the C (Arg452) allele of the missense rs1053230C>T variant (KMO Arg452Cys) showed a trend effect on cognitive function. Neither variant affected P50 gating. Conclusions These data suggest that KMO variation influences a range of cognitive domains known to predict functional outcome. Extensive molecular characterization of this gene would elucidate its role in cognitive function with implications for vertical integration with basic discovery.
Microstructural Properties of Fly Ashes from Oklahoma and Wyoming Coals and their Blends

Blending of different types of coals is an economical method of utilizing locally available lower quality coals. Four blends of Wyoming/Oklahoma coal were prepared (100:0, 90:10, 75:25, 0:100) and burned in a laboratory furnace in a diffusion flame of a mixture of propane and nitrogen in air. Flame temperatures ranged from 1419 K for Oklahoma to 1626 K for Wyoming coal. The higher temperatures indicate better boiler utility, more oxidation, less free carbon, more and better quality fly ash. These observations conform well with the SEM evaluations which indicated that as the amount of Wyoming coal increased, the matrix contained densely populated glassy spherical particles. The SEM data on cured paste samples indicated that the Wyoming fly ash showed a better tendency to crystal (presumably ettringite) formation, followed by the blends of 90% Wyoming-10% Oklahoma and 75% Wyoming-25% Oklahoma. The least amount of crystal formation was observed in the fly ash of 100% Oklahoma coal. These effects are extremely pronounced in the early curing stages.
Sodium and Sugar Fluxes across the Mucosal Border of Rabbit Ileum

Unidirectional influxes of sugars and Na from muscosal solution into the cells of rabbit ileum have been examined. The influxes of glucose, galactose, and 3-0-methyl glucose (3 MG) follow Michaelis-Menten type kinetics and are markedly dependent on the presence ofNa in the mucosal solution. For 3 MG, reduction of Na concentration causes a decrease in maximal rate of influx and little change in the "apparent Michaelis constant." There appeared to be little mediated entry of 3 MG into the cells from Na-free solution. The influx of Na was increased by the presence of 3 MG in the mucosal solution and at all Na concentrations tested, there was a 1:1 ratio between sugar influx and the sugar-dependent Na influx. On the basis of these observations, a model has been developed for the sugar transport system involving a transport site that combines with both sugar and Na.
Improving Students' Exam Performance by Introducing Study Strategies and Goal Setting

This study addresses whether learning strategies would improve students' exam performance. Students in 2 sections (N = 65) of Introductory Psychology participated. I introduced students in the experimental section to learning strategies. Students set individual learning goals and recorded their learning related behavior during the first 2 units. Students in the control condition engaged in nonacademic tasks. All students experienced a lesson on learning at the end of Unit 2. First-year students in the control condition obtained significantly lower scores than all other students on the first 2 exams. On the 3rd exam, differences were not significant. On the final exam, the original pattern reemerged.
Wnt signaling activation and mammary gland hyperplasia in MMTV–LRP6 transgenic mice: implication for breast cancer tumorigenesis

Although Wnt signaling activation is frequently observed in human breast cancer, mutations in genes encoding intracellular components of the Wnt signaling pathway are rare. We found that the expression of Wnt signaling co-receptor, LRP6, is upregulated in a subset of human breast cancer tissues and cell lines. To examine whether the overexpression of LRP6 in mammary epithelial cells is sufficient to activate Wnt signaling and promote cell proliferation, we generated transgenic mice overexpressing LRP6 in mammary epithelial cells driven by the mouse mammary tumor virus (MMTV) promoter. We found that mammary glands from MMTV-LRP6 mice exhibit significant Wnt activation evidenced by the translocation of beta-catenin from membrane to cytoplasmic/nuclear fractions. The expression of several Wnt target genes including Axin2, Cyclin D1 and c-Myc was also increased in MMTV-LRP6 mice. More importantly, mammary glands from virgin MMTV-LRP6 mice exhibit significant hyperplasia, a precursor to breast cancer, when compared with wild-type littermate controls. Several matrix metalloproteinases are upregulated in MMTV-LRP6 mice that could contribute to the hyperplasia phenotype. Our results suggest that Wnt signaling activation at the cell-surface receptor level can contribute to breast cancer tumorigenesis.
Synthesis of TOAC spin-labeled proteins and reconstitution in lipid membranes

A procedure is described for the synthetic incorporation into membrane proteins of the non-natural amino acid TOAC (2,2,6,6-tetramethyl-piperidine-1-oxyl-4-amino-4-carboxylic acid), which is coupled rigidly to the α-carbon, providing direct detection of peptide backbone dynamics by electron paramagnetic resonance (EPR). Also included is a protocol for the functional reconstitution of the spin-labeled protein in lipid vesicles. This protocol can be completed in 17 d.
Computer-aided design of 3d integrated circuits

Unlike conventional electronic circuits, where transistors are placed in a single plane, three-dimensional (3D) integrated circuits utilize multiple tiers of active devices, placed one above another. Recent advances in processing technologies have brought these technologies into the realm of achievable reality, and today, several academic, corporate and government labs run fabrication processes for building 3D integrated circuits. The move to the third dimension immediately provides increased packing densities per unit footprint, and provides a path for maintaining Moore's law rates of growth at the system level, even as questions are being raised about the sustainability of device-level scaling. 3D circuits offer numerous other advantages as well, including the potential for reduced interconnect lengths, and the ability to easily integrate heterogeneous technologies on multiple tiers into a single package.This new paradigm brings forth a number of novel and interesting challenges, and raises the necessity for novel design and CAD techniques. A direct translation of a 2D design to 3D can lead to a suboptimal implementation that does not fully exploit the power of 3D, and 3D-specific approaches are essential. At the most fundamental level, 3D circuit design is a physical design problem; therefore, new methods for floorplanning, placement and routing must be developed within this paradigm. These techniques must work within the additional degrees of freedom as well as the new constraints imposed by this technology, such as restrictions on interlayer vias, as well as circuit limitations due to increased packing densities, particularly those related to the challenges of heat removal and power delivery.