cssi/SciSciGPT-SciSciNet huggingface dataset:
Phytoplankton photosynthesis parameters along 140°W in the equatorial Pacific

Abstract The role of trace metal limitation in the maintenance of the high nutrient and low chlorophyll condition in eastern equatorial Pacific surface waters remains controversial. On the EqPac Survey II cruise, photosynthesis versus irradiance (P-I) and phytoplankton spectral absorption were measured along 140°W from 12°N to 12°S in the eastern tropical Pacific to determine the spatial variability of P-I parameters in relation to the light, macronutrient, and trace metal regime. The latitudinal patterns of the maximum quantum yield of photosynthesis (φm) and carotenoid-corrected spectral absorption covaried with the concentration of N03 at 60 m, a proxy for the macronutrient supply rate. At the equator, the maximum quantum yield of phytoplankton photosynthesis was less than half that expected for nutrient-replete phytoplankton. This indicates that phytoplankton photosynthesis was nutrient limited even though N03 concentrations at the equator exceeded 6 μmol kg−1. When φm was corrected for absorption by photoprotective carotenoids, maximum values were found at 12°N and values declined linearly with latitude to 12°S. This pattern is coincident with the putative atmospheric iron flux and the distribution of dissolved iron. These observations support the hypothesis that the photosynthesis of equatorial phytoplankton is regulated by iron availability. Phytoplankton photosynthetic performance and in situ chlorophyll-normalized primary production along 140W appeared to be regulated by the interaction of macronutrient and trace metal supply rates on phytoplankton photoacclimation processes.
The impact of school quality, socio-economic factors and child health on students academic performance : evidence from Sri Lankan primary schools

One of the eight Millennium Development Goals (MDGs) is that all children in developing countries should complete primary education. Much progress has been made toward this goal, but completing primary school does not ensure that students attain basic literacy and numeracy skills. Indeed, there is ample evidence that many children in developing countries are not learning these basic skills. This raises the question: What can schools and communities do to increase the learning that takes place in schools? Sri Lanka exemplifies these issues. It has achieved universal primary completion, but many Sri Lankan primary school students perform poorly on academic tests. This paper uses unusually rich data from Sri Lanka to investigate the determinants of academic performance, as measured by achievement tests, of grade 4 students. At the child and household level, educated parents, better nutrition, high daily attendance, enrollment in private tutoring classes, exercise books, electric lighting and children's books at home all appear to increase learning, while hearing problems have a strong negative effect. Among school variables, principals' and teachers' years of experience, collaborating with other schools in a 'school family', and meetings between parents and teachers all appear to have positive impacts on students' scores. Estimates that exclude some of the variables available in the unusually rich data yield different results, which suggest that results based on less complete data are likely to suffer from omitted variable bias. A final section provides recommendations for education policies in Sri Lanka.
On the Foundations of Vision Modeling III. Noncommutative Monoids of Occlusive Preimages

A significant cue for visual perception is the occlusion pattern in 2-D retinal images, which helps humans or robots navigate successfully in the 3-D environments. There have been many works in the literature on the modeling and analysis of the occlusion phenomenon, most of which are from the analytical or statistical points of view. The current paper presents a new theory of occlusion based on the simple topological definitions of preimages and a binary operation on them called "occlu." We study numerous topological as well as algebraic structures of the resultant noncommutative preimage monoids (a monoid is a semigroup with identity). Some implications of the new theory in terms of real vision research are also addressed.
Transcription Factor Nrf2 Protects HepG2 Cells against CYP2E1 plus Arachidonic Acid-dependent Toxicity

Nrf2 is a transcription factor that regulates important antioxidant and phase II detoxification genes. Arachidonic acid (AA) causes CYP2E1-dependent toxicity in HepG2 cells. The ability of Nrf2 to protect against CYP2E1-dependent AA toxicity and its possible mechanism were evaluated. AA activates Nrf2 in CYP2E1-expressing HepG2 cells (E47 cells), increasing Nrf2 protein and mRNA levels, Nrf2 nuclear translocation, and Nrf2-ARE binding activity. These increases in Nrf2 are associated with elevated expression of Nrf2-regulated antioxidant genes. Overexpression of Nrf2 by transient transfection of plasmid Nrf2 confers resistance of E47 cells against AA toxicity. Blocking Nrf2 with small interfering RNA (siRNA)-Nrf2 potentiates the CYP2E1-dependent AA toxicity. This enhanced toxicity is accompanied by decreases of cellular GSH levels and increases in production of reactive oxygen species and lipid peroxidation. There is also a potentiation of mitochondrial damage in the presence of siRNA-Nrf2. The protective effects of Nrf2 against CYP2E1-dependent toxicity can be blocked by l-buthionine-(S,R)-sulfoximine, a specific inhibitor of glutamate-cysteine ligase, which is a rate-limiting enzyme in the synthesis of GSH and is regulated by Nrf2. Elevation of GSH by supplementing with glutathione ethyl ester can partially reverse the enhanced AA toxicity by siRNA-Nrf2. Moreover, in contrast to AA, l-buthionine-(S,R)-sulfoximine toxicity is not prevented by plasmid Nrf2 probably because protective GSH cannot be synthesized. Together, these results suggest that Nrf2, through up-regulation of glutamate-cysteine ligase and increase of GSH levels, protects against CYP2E1-dependent AA toxicity.
Effect of ocean dumping on 13C/12C ratios in marine sediments from the New York Bight

In order to evaluate the influence of the ocean dumping of sewage sludge upon the organic carbon fraction of sediments of the New York Bight, a study of carbon isotopic variations in surface sediments from the area has been completed. On the basis of our 13C/12C measurements, it appears that: (1) sewage is depleted in 13C as compared to average marine organic sedimentary carbon, and (2) δ13C values from sediments of the New York Bight show systematic variations which are a direct consequence of the sludge disposal. Based on assumptions regarding inputs of sedimentary carbon to the sea floor in this area, we have modeled these 13C/12C variations in terms of progressive dilution of normal marine carbon with carbon derived from the ocean dumping of wastewater sludges. The isotopic composition of carbon in sediments from the New York Bight may serve as a quantitative tracer of sewage sludge components.
Sexual harassment and the communication conundrum

The rise of both sexual harassment complaints and litigation has made many companies react with strict no tolerance policies causing widespread concern among employees that anything they say might be misconstrued and lead to their termination. This fear is largely unjustified. Most people understand what is being said and do not misinterpret offhand and innocent remarks as sexually harassing. This paper examines some of the areas where the sexes are in agreement as to what does and does not constitute sexual harassment. In doing so, certain forms of behavior are discerned that pose a particular problem. By pinpointing specific areas where communication is especially ambiguous, educators and trainers can focus their resources and dramatically reduce sexual harassment in the workplace.
Wind Tunnel Aeroacoustic Tests of Six Airfoils for Use on Small Wind Turbines; Period of Performance: August 23, 2002 through March 31, 2004

The U.S. Department of Energy, working through the National Renewable Energy Laboratory, is engaged in a comprehensive research effort to improve our understanding of wind turbine aeroacoustics. Quiet wind turbines are an inducement to widespread deployment, so the goal of NREL's aeroacoustic research is to develop tools that the U.S. wind industry can use in developing and deploying highly efficient, quiet wind turbines at low wind speed sites. NREL's National Wind Technology Center is implementing a multifaceted approach that includes wind tunnel tests, field tests, and theoretical analyses in direct support of low wind speed turbine development by its industry partners. To that end, wind tunnel aerodynamic tests and aeroacoustic tests have been performed on six airfoils that are candidates for use on small wind turbines. Results are documented in this report.
Reopening the American West

Take a good look at the American West and you'll see that the frontier is undergoing constant changes not only changes made to the land but also changes in attitudes about the land held by the people who live there. In this book Mike Davis, Stephen Pyne, William deBuys, Donald Worster, Dan Flores, and others re-examine the relationship between people and the environment in the American West over five hundred years, from the legacy of Coronado's search for the Cities of Gold to the social costs of tourism and gaming inflicted by modern adventurers. By exploring places in the West, aspects of the region's past, and ways of understanding some of its pressing issues, the authors foster a better understanding of how people interact and perceive land. Reopening the American West takes a fresh approach to the history of the region, examining the premises of earlier scholars as well as those who have redefined the study of the West over the past two decades. It combines provocative essays with insightful analyses to address issues that are representative of the West in the twentieth century multiculturalism, water issues, resource exploitation and to reopen the West for all readers interested in new ways of looking at its wide-open spaces. CONTENTS-Places-Dreams of Earth, William deBuys-Environmentalism and Multiculturalism, Dan L. Flores-Pyre on the Mountain, Stephen J. Pyne-Las Vegas Versus Nature, Mike Davis-Pasts: The Legacy of John Wesley Powell, Donald Worster-Pokey's Paradox: Tourism and Transformation on the Western Navajo Reservation, Hal Rothman-Negotiating National Identity: Western Tourism and "See American First," MargueriteSchaffer-Understanding-Place Humanists at the Headgates, Helen Ingram: Tapping the Rockies: Resource Exploitation and Conservation in the Intermountain West, Char Miller: The Meaning of Place: Reimagining Community in a Changing West, Robert Gottlieb
Mn2+ Suppressor Mutations and Biochemical Communication between Ty1 Reverse Transcriptase and RNase H Domains

Ty1 reverse transcriptase/RNase H (RT/RH) is exquisitely sensitive to manganese concentrations. Elevated intracellular free Mn(2+) inhibits Ty1 retrotransposition and in vitro Ty1 RT-polymerizing activity. Furthermore, Mn(2+) inhibition is not limited to the Ty1 RT, as this ion similarly inhibits the activities of both avian myeloblastosis virus and human immunodeficiency virus type 1 RTs. To further characterize Mn(2+) inhibition, we generated RT/RH suppressor mutants capable of increased Ty1 transposition in pmr1 Delta cells. PMR1 codes for a P-type ATPase that regulates intracellular calcium and manganese ion homeostasis, and pmr1 mutants accumulate elevated intracellular manganese levels and display 100-fold less transposition than PMR1(+) cells. Mapping of these suppressor mutations revealed, surprisingly, that suppressor point mutations localize not to the RT itself but to the RH domain of the protein. Furthermore, Mn(2+) inhibition of in vitro RT activity is greatly reduced in all the suppressor mutants, whereas RH activity and cleavage specificity remain largely unchanged. These intriguing results reveal that the effect of these suppressor mutations is transmitted to the polymerase domain and suggest biochemical communication between these two domains during reverse transcription.
Three-Dimensional Particle Simulations of Ion-Optics Plasma Flow and Grid Erosion

A fully three-dimensional computer particle simulation model for ion optics is developed. This model allows multiple apertures to be included explicitly in the simulation domain and determines the upstream sheath and downstream beam neutralization through simulations. Simulations are performed for the NSTAR ion-thruster optics, and results are compared with grid-erosion measurements obtained during NSTAR long-duration test. It is shown that the simulation not only predicts accurately all of the features in the measured erosion pattern but also gives excellent quantitative agreement with the measured erosion depth.
Modeling the effect of spatial externalities on invasive species management.

Abstract Changes in production conditions associated with biological invasions can be complex. As a result, modeling invasive species management decisions can be difficult. Modeling these decisions is further compounded by externalities associated with spatial relationships among growers. In order to calculate optimal management decisions, an accurate bioeconomic model of the feedback between grower decisions and the new biological interactions created by an invasive species population is needed. In this paper, a bioeconomic model is used to explicitly analyze how externalities caused by spatial relationships among agricultural producers affect optimal invasive species management decisions. The example of the coordinated greenhouse whitefly management in the Oxnard, CA, area is discussed. This is an interesting example because of the complex cycle of host crops used by the whitefly and the effect this cycle has on the optimal whitefly management decisions for strawberry growers. Three research objectives achieved in this paper include first, using the model to assess how the spatial relationship among growers affects incentives for regional invasive pest management. Second, analyze whether current policies could be adjusted to substitute for coordination among growers. Third, the use of the bioeconomic model to identify factors for this specific case that affect whether or not growers may voluntarily coordinate their management decisions. I find that spatial relationships among growers affect the need for coordination in the strawberry/whitefly case. Whitefly migrations across host crop fields require growers to manage the whitefly on a regional basis in order to maximize strawberry producer welfare. The results also indicate that the amount of effort needed to achieve coordination required is limited; the only requirement is that information related to field management be shared among growers of whitefly host crops. The results from the bioeconomic model describe the biological and economic feedback of the grower’s decision which allows policymakers to identify the willingness of producers to coordinate at various times of year. In the Oxnard strawberry/whitefly case, for example, growers will not find it optimal to adjust their application timing for a second immigration of adult greenhouse whiteflies when they occur near the end of the season, such as in May or June, but will for earlier points in the season. Three policy implications of the results from the strawberry/whitefly case are also discussed in the paper. First, adjustments to current policies regulating whitefly management do not remove the need for coordination among growers to them. Also, it was found that current policies do not, by themselves, generate the need for coordination. Finally, the results show it is not always necessary to create a central agency for regional invasive species management.
Closing the power gap between ASIC and custom: an ASIC perspective

We investigate differences in power between application-specific integrated circuits (ASICs) and custom integrated circuits, with examples from 0.6/spl mu/m to 0.13/spl mu/m CMOS. A variety of factors cause synthesizable designs to consume /spl times/3 to /spl times/7 more power. We discuss the shortcomings of typical synthesis flows, and changes to tools and standard cell libraries needed to reduce power. Using these methods, we believe that the power gap between ASICs and custom circuits can be closed to within /spl times/2.
Studies of Soiling and Detergency Part IV: Deposition and Transfer Experiments With Fatty Soils

A study was made of the transfer of compounds, similar to those found in human sebum, from cellulose to polyethylene terephthalate films and the deposition of these soils on polymer films from surf...
Disentangling Energy Policy from Environmental Policy

Objectives. I attempt to disentangle energy policy from environmental policy in order to explain the shifting politics surrounding the former. I can then explain why energy policies have historically provided distributive benefits but also the implications of the fact that energy proposals have in recent years become more regulatory in nature. Methods. I use a range of methods. These include qualitative accounts of the evolution of energy policy, graphic depictions of congressional activity, spending, and partisanship, and multivariate analyses of oversight activities. Results. I find that policymakers have historically treated energy issues as distributive policy, resulting in an emphasis on spending and oversight but not on substantial legislation. Over the last three decades, as policymakers push energy proposals that are more regulatory in nature, energy politics have become more divisive and partisan. Conclusion. Ultimately, I conclude that the enactment of strong energy policies will necessarily involve conditions that have been conducive to passage of other strong regulatory policies.
Clinical application of tissue doppler imaging in patients with idiopathic pulmonary hypertension

Background:Tissue Doppler (TD) echocardiographic imaging of mitral and tricuspid annulus has been applied to assess right ventricular (RV) and left ventricular (LV) function in many cardiac diseases, but its clinical application, including response to long-term targeted therapy in patients with idiopathic pulmonary hypertension (PH), has not been addressed. Methods:Seventy patients with idiopathic PH were compared with 35 age-matched control subjects to examine myocardial velocities by TD. Of these, 35 patients underwent repeat imaging after long-term targeted therapy. In addition, 50 consecutive patients with idiopathic PH with simultaneous right-heart catheterization and echocardiography were examined. Results:No significant differences were noted between PH patients and the control group in lateral mitral annulus systolic velocity and early diastolic velocity (Ea) by TD, but septal velocities were significantly lower (p < 0.01). With targeted therapy, myocardial velocities at the septum and RV free wall increased significantly (p < 0.05). Likewise, E/Ea ratio increased, albeit still in the normal range. In all 50 patients with invasive measurements, lateral E/Ea ratio readily identified normal mean pulmonary capillary wedge pressure (PCWP). Conclusions:TD imaging of the lateral mitral annulus can reliably predict the presence of normal/reduced mean PCWP in patients with idiopathic PH, and track the improvement in RV function and LV filling with long-term targeted therapy.
Distribution, diel movement, and growth of the grass shrimp Palaemonetes paludosus in the Kissimmee River-floodplain ecosystem, Florida

Autrefois, la riviere Kissimmee effectuait des meandres dans une large plaine humide inondable. En reponse aux crues catastrophiques et aux imperatifs de la reglementation en Floride Centrale, la riviere fut canalisee, transformant le reseau fluvial complexe en un canal rectiligne. Le resultat fut une forte diminution des habitats riverains et des communautes associees. Sitot apres la fin des travaux de canalisation, par souci de l'environnement, l'Etat de Floride fut amene a examiner les options de restauration aptes a retablir l'hydrologie naturelle de la riviere et a recreer les zones humides disparues. La crevette Palaemonetes paludosus fut identifiee dans ce systeme comme une espece cle d'invertebre. Cette etude avait pour objet d'examiner sa repartition, sa migration journaliere et sa croissance dans les deux communautes dominantes de macrophytes des marais riverains de la riviere : Nuphar et Polygonum. Les resultats montrent que la crevette etait plus abondante dans les herbiers de Polygonum. Cette espece ne montrait egalement pas de migration journaliere bien definie bien que nous ayons parfois observe un deplacement vertical significatif. La croissance de Palaemonetes paludosus etait plus forte sur le periphyton et sur les feuilles de Polygonum. La repartition des crevettes peut s'expliquer par leur sensibilite moindre a la predation a cause de la plus grande complexite des habitats dans les herbiers de Polygonum.
The select action of hippocampal calcium calmodulin protein kinase II in mediating exercise-enhanced cognitive function

We found that a single week of exercise enhanced cognitive function on the Morris water maze (MWM), such that exercise animals were significantly better than sedentary controls at learning and recalling the location of the platform. In order to elucidate the role that calcium calmodulin protein kinase II (CAMKII) holds in mediating the exercise-induced enhancement in learning and memory, a specific antagonist of CAMKII, KN-62, was used to block CAMKII in the rat hippocampus during a 1-week voluntary exercise period. Following, a two-trial-per-day MWM was performed for five consecutive days, succeeded by a probe trial 2 days later. Inhibiting CAMKII action during exercise blocked the ability of exercise to enhance memory retention on the MWM; the recall abilities of exercise animals receiving the CAMKII blocker were significantly worse than those of both sedentary and exercise controls. Conversely, CAMKII may not play a significant role in mediating the effects of exercise on learning acquisition as inhibiting CAMKII failed to block the exercise-induced enhancement in learning acquisition. Our results also show that CAMKII activation early during MWM learning may be counterproductive to learning acquisition, as exercising animals given the CAMKII inhibitor performed significantly (P<0.001) better than exercising control animals and sedentary controls only on day 2 of the MWM. Inhibiting CAMKII also blocked the exercise-induced upregulation of molecules critical for learning and memory, brain-derived neurotrophic factor (BDNF) and the transcription activator cAMP response-element-binding protein, which is regulated by and downstream to BDNF action. These findings indicate that hippocampal CAMKII may have a refined role in mediating the effects of exercise on cognition, selectively functioning to regulate memory retention.
Early detection of emerging forest disease using dispersal estimation and ecological niche modeling

Distinguishing the manner in which dispersal limitation and niche requirements control the spread of invasive pathogens is important for prediction and early detection of disease outbreaks. Here, we use niche modeling augmented by dispersal estimation to examine the degree to which local habitat conditions vs. force of infection predict invasion of Phytophthora ramorum, the causal agent of the emerging infectious tree disease sudden oak death. We sampled 890 field plots for the presence of P. ramorum over a three-year period (2003-2005) across a range of host and abiotic conditions with variable proximities to known infections in California, USA. We developed and validated generalized linear models of invasion probability to analyze the relative predictive power of 12 niche variables and a negative exponential dispersal kernel estimated by likelihood profiling. Models were developed incrementally each year (2003, 2003-2004, 2003-2005) to examine annual variability in model parameters and to create realistic scenarios for using models to predict future infections and to guide early-detection sampling. Overall, 78 new infections were observed up to 33.5 km from the nearest known site of infection, with slightly increasing rates of prevalence across time windows (2003, 6.5%; 2003-2004, 7.1%; 2003-2005, 9.6%). The pathogen was not detected in many field plots that contained susceptible host vegetation. The generalized linear modeling indicated that the probability of invasion is limited by both dispersal and niche constraints. Probability of invasion was positively related to precipitation and temperature in the wet season and the presence of the inoculum-producing foliar host Umbellularia californica and decreased exponentially with distance to inoculum sources. Models that incorporated niche and dispersal parameters best predicted the locations of new infections, with accuracies ranging from 0.86 to 0.90, suggesting that the modeling approach can be used to forecast locations of disease spread. Application of the combined niche plus dispersal models in a geographic information system predicted the presence of P. ramorum across approximately 8228 km2 of California's 84785 km2 (9.7%) of land area with susceptible host species. This research illustrates how probabilistic modeling can be used to analyze the relative roles of niche and dispersal limitation in controlling the distribution of invasive pathogens.
Yield and economics of traditional and early soybean production system (ESPS) seedings in the midsouthern United States

Abstract Drought stress reduces yield of traditional May and June seedlings of soybean in midsouthern USA. Field experiments using Maturity Group (MG) IV and MG V soybean cultivars were conducted at Stoneville, Mississippi (latitude 33°26′ N) for five years to determine effects of earlier-than-normal (April) and normal (May) seeding on net returns from soybean grown with, and without, irrigation. Net returns were calculated as the difference between income and all direct and indirect costs excluding those for land, management, and general farm overhead. In the irrigated environment, average net returns from April seedings of MG IV cultivars were greater than those from May seedings in all years, while average net returns from April seedings of MG V cultivars were greater than those from May seedings in all years except 1997. These greater net returns resulted from larger seed yields, lower estimated costs, higher prices received for harvested seed, or a combination of the three. Average net returns from April seedings ranged from US$ 148 to US$ 617/ha, while average net returns from May seedings ranged from US$ 69 to US$ 567/ha. Use of MG IV vs. MG V cultivars had no consistent effect on net returns from either April or May seedings. In the nonirrigated environment, average net returns from April seedings of all cultivars were greater than those from May seedings in all years. Average annual net returns from cultivars seeded in April ranged from US$ 74 to US$ 374/ha, while average annual net returns from May seedings ranged from US$ −9 to US$ 325/ha. In three of the five years, MG V cultivars sown in April produced more yield and greater net return than did MG IV cultivars, while April-sown MG IV cultivars produced the highest yield and net return in one of the five years in the nonirrigated study. These results indicate that earlier-than-normal (April) seedings of either MG IV or MG V soybean cultivars will result in increased net return vs. that attained from traditional (May or later) seedings in the midsouthern USA. These results also indicate that choosing cultivars within an MG is more critical than choosing between MG IV and V.
A case study of a career in education that began with "Teach for America"

In this article I share the results of a seven‐year case study of an educator who began his career without formal preservice teacher education, as a participant in Teach for America. Steven (a pseudonym) began teaching mathematics in an urban middle school, later teaching social studies to English language learners, and is currently a principal of an urban charter school. Using a narrative/biographical research method, I have documented how Steven combined his personal resources, the confidence he gained from participating in Teach for America, and, because he began taking professional coursework in his second year of teaching, his emerging understanding of the foundations of teaching and learning (i.e. what he learned at the university) to form the educator he has become. His growth in understanding the culture of his students is a particularly compelling part of his story. Implications for contemporary teacher education are discussed, including the role of multicultural education courses and why customi...
Flash: an efficient and portable web server

This paper presents the design of a new Web server architecture called the asymmetric multi-process event-driven (AMPED) architecture, and evaluates the performance of an implementation of this architecture, the Flash Web server. The Flash Web server combines the high performance of single-process event-driven servers on cached workloads with the performance of multiprocess and multi-threaded servers on disk-bound workloads. Furthermore, the Flash Web server is easily portable since it achieves these results using facilities available in all modern operating systems. The performance of different Web server architectures is evaluated in the context of a single implementation in order to quantify the impact of a server's concurrency architecture on its performance. Furthermore, the performance of Flash is compared with two widely-used Web servers, Apache and Zeus. Results indicate that Flash can match or exceed the performance of existing Web servers by up to 50% across a wide range of real workloads. We also present results that show the contribution of various optimizations embedded in Flash.
Direct Water–Fat Imaging Methods: Chemical Shift‐Selective and Chemical Shift‐Encoded MRI

This article summarizes direct imaging methods designed to separate water and fat signals in proton magnetic resonance imaging. The methods presented fundamentally rely on the difference in resonance frequencies between water (hydroxyl) and predominant fat (methylene) protons. The discussed techniques are divided into two categories, (i) RF-based approaches that selectively suppress or excite water and fat signals and (ii) multiecho imaging strategies that separate water and fat signals based on chemical shift-encoding. The various clinical utilities of these methods are detailed, from traditional fat suppression endpoints to more recent trends toward quantitative fat-fraction imaging. Comparative examples are illustrated, along with some discussion of the advantages and limitations of each method. In the context of quantitative fat imaging, the impact of modeling fat more realistically, as a multipeak triglyceride signal versus a traditional simplified single-methylene-peak representation, is highlighted, and similarly, the effects of confounding factors on quantitative accuracy and precision are summarized. Approaches to multiecho chemical shift-encoded data acquisitions and reconstructions are presented, and methodological considerations for echo-time selection and main magnetic field inhomogeneity are outlined. Finally, recent advances in chemical shift-encoded imaging toward the characterization of triglyceride properties (e.g., chain length and unsaturation degree) are briefly discussed. Keywords: chemical shift-selective imaging; chemical shift-encoded imaging; Dixon imaging; proton-density fat fraction; fat suppression; fat quantification; multiecho imaging; signal fat fraction; water–fat separation; water excitation
Predation on Heliothis zea (Lepidoptera: Noctuidae): an Instar-Specific Elisa Assay for Stomach Analysis

Quantitative data on arthropod predation are difficult to obtain because of the secretiveness and feeding modes of predators and because of the antigenic similarities of closely related prey species and of different stages and instars of the same prey species. A monoclonal antibody (MAB) to the arylphorin of Heliothis zea (Boddie) distinguishes remains of fifth instars in enzyme-linked immunosorbent assay (ELISA) of fed predator extracts from the remains of all other instars and eggs of this and related species. This demonstrates the feasibility of using MAB-based ELISA in life table and other long-term quantitative predation studies. Improvements in our ELISA protocol double the rate at which assays can be performed without compromising sensitivity or specificity. This is the first reported MAB-based ELISA for arthropod predator stomach analysis and the first to achieve instar-specificity.
American Prices and Urban Inequality Since 1820

This article examines the forces that appear to have driven long-term trends in American urban inequality. The changing structure of consumer goods' prices is shown to have played a significant—but not dominant—role in every phase of increasing and decreasing nominal inequality from 1820 to 1929. The revealed symmetry in movement between the urban price and income structure suggests that a successful macro-distribution model must explain both historical phenomena. Finally, the article concludes that technological imbalance was a crucial element in shaping peacetime patterns of income distribution.
Clinical features and prognosis of severe chronic active liver disease (CALD) after corticosteroid-induced remission.

Abstract Disappearance of symptoms, resolution of most biochemical abnormalities, and histologic improvement to mild chronic inflammation were accomplished in 69 of 123 patients (56%) with severe chronic active liver disease treated with corticosteroids for up to 6.5 yr. Remission of at least 6 mo duration was possible in 35 of the 69 (51%) after discontinuation of therapy while others relapsed promptly and required retreatment. The likelihood of sustained remission was not predicted by initial clinical or biochemical features, although patients developing cirrhosis during treatment invariably relapsed. Subsequent courses of treatment after relapse were equally effective in again inducing remission, but the probability of another relapse increased after each successive therapy and was 86% after three treatments. Six of twenty-two patients (27%) followed for at least 4 yr after initial remission had three or more relapses. Although patients who relapsed were more likely to develop cirrhosis, manifestations of portal hypertension and immediate survival were not affected by relapse. Complete disappearance of all manifestations of active disease was possible in 12 of the patients entering remission (17%), but only patients without cirrhosis consistently sustained this improvement. We conclude that relapse after cessation of therapy frequently follows corticosteroid-induced remission of severe CALD, especially if cirrhosis develops, but does not jeopardize response to subsequent treatments or alter early prognosis.
Internal gravity waves generated by a turbulent bottom Ekman layer

Internal gravity waves excited by the turbulent motions in a bottom Ekman layer are examined using large-eddy simulation. The outer flow is steady and uniformly stratified while the density gradient is set to zero at the flat lower wall. After initializing with a linear density profile, a mixed layer forms near the wall separated from the ambient stratification by a pycnocline. Two types of internal wave are observed. Waves with frequencies larger than the free-stream buoyancy frequency are seen in the pycnocline, and vertically propagating internal waves are observed in the outer layer with characteristic frequency and wavenumber spectra. Since a signature of the pycnocline waves is observed in the frequency spectrum of the mixed layer, these waves may affect the boundary-layer turbulence. The dominant outer-layer waves have a group velocity directed 35-60° from the vertical axis, which is consistent with previous laboratory studies. The energy flux associated with the radiated waves is small compared to the integrated dissipation in the boundary layer, but is of the same order as the integrated buoyancy flux. A linear model is proposed to estimate the decay in wave amplitude owing to viscous effects. Starting from the observed wave amplitudes at the bottom of the pycnocline, the model prediction for the spectral distribution of the outer layer wave amplitude compares favourably with the simulation results.
An active square loop frequency selective surface

An active frequency selective surface incorporating PIN diodes as switches is discussed. Waveguide simulation studies show that the frequency response of the surface can be electronically switched from that of a reflecting structure to a transmitting structure. A semi-empirical model based on a series-connected LC equivalent circuit approach gives agreement with measurements. >
Asymmetric, multi-conductor low-coupling structures for high-speed, high-density digital interconnects

Due to the increasing speeds of digital circuits and the small interline spacings, a full-wave analysis of multilayer, multiconductor structures is required to accurately predict the coupling and crosstalk on these structures. Using the spectral domain approach, it is shown that substrate compensation can be used for asymmetric coupled lines and symmetric multiconductor lines. Some of the characteristics of substrate compensated low-coupling structures were also investigated, showing that one substrate configuration can be used to reduce coupling and crosstalk with a variety of conductor configurations. It is concluded that, by designing high-speed interconnects with substrate compensation, it will be possible to achieve an extremely high density of signal conductors, using interline spacings of less than one center conductor width, while keeping crosstalk and coupling distortion to a minimum. >
Lime-Treated Soils For Pavement Construction

An evaluation of the properties and characteristics of lime-treated soils and an analysis of service conditions (stresses, displacements, durability) for lime-soil pavements layers indicate that lime-stabilized soils can be used for many highway-pavement applications. The quality of the lime-soil mixture must be assessed prior to determining its use in the pavement system, i.e., modified subgrade, subbase, base. Tentative quality requirements, based on unconfined compressive strength, are presented for various usages.
Asset Allocation: IRAs and 401(k)-Type Plans

As individuals accumulate assets for their retirement, one of the most important decisions - after the first necessity of saving money - is how the assets are invested. The distribution of the savings across stocks, bonds, money market accounts, savings accounts, and other investments is referred to as asset allocation; once money is saved, its allocation (how it is invested) determines how fast it will grow. Equities (stocks) have historically had higher rates of return, over time, than interest-earning investments such as bonds and money market accounts, leading to faster capital accumulation. Because of the critical importance of how retirement savings are invested, the Employee Benefit Research Institute (EBRI) has examined the asset allocation of 401(k) retirement savings plan participants in the past, most recently by using the EBRI/ICI 401(k) participant database. This article supplements that research with data from the Survey of Consumer Finances (SCF), conducted by the Federal Reserve, to study the asset allocation of family heads in both individual retirement accounts (IRAs) and 401(k)-type plans. (The Fed's SCF measures wealth at the family level, so its findings are presented as percentages of American families and/or family heads, rather than all individuals.) The PDF for the above title, published in the October 2000 issue of EBRI Notes, also contains the fulltext of another October 2000 EBRI Notes article abstracted on SSRN: "The Impact of Workers' Earnings Profiles on Individual Account Accumulation."
Promising new therapies for the treatment of hypercholesterolemia

ABSTRACTIntroduction: Statins are currently the most commonly used agents for treatment of hypercholesterolemia in patients with atherosclerotic cardiovascular disease. However, some patients on statins do not achieve their treatment goals or are intolerant to statins. Therefore, new therapies for treatment of hypercholesterolemia are under investigation.Areas covered: This article reviews the new emerging medications for the treatment of hypercholesterolemia and discusses their efficacy and safety profile based on literature searches that included human studies published on PubMed and reported clinical trials.Expert opinion: Inhibition of the PCSK9 protein by monoclonal antibodies results in a dramatic 40%-60% lowering of serum low-density lipoprotein cholesterol (LDL-C). This is in addition to LDL-C lowering achieved by statins. Multiple clinical studies have demonstrated the high selectivity of these antibodies for the PCSK9 pathway and their long-term safety and efficacy. Alirocumab and evolocumab hav...
Sexually Transmitted Infection Testing Among Adolescents and Young Adults in the United States.

Abstract Purpose Persons aged 15–25 years have high sexually transmitted infection (STI) rates and suboptimal screening. There has been limited research analyzing barriers to STI testing at a national level. We examined STI testing among 15–25 year olds and reasons for not testing. Methods We used data from a national survey of youth. Bivariate and multivariable analyses examined differences in testing behaviors by demographics, separately by sex. Among sexually experienced respondents who reported never being tested, health system–related reasons for not testing were examined in bivariate and multivariable analyses. Results Females (16.6%) were more likely to have ever been tested compared with males (6.1%, p p p Conclusions This national-level study found that most of the 15–25 year olds never received an STI test. In addition, confidentiality concerns may deter youth from seeking STI testing. Appropriate strategies to minimize these concerns may be useful. Potential strategies to ameliorate these issues may include engaging clinicians who frequently serve adolescents and young adults to address confidentiality issues with youth patients.
Clostridium perfringens Enterotoxin: Action, Genetics, and Translational Applications

Clostridium perfringens enterotoxin (CPE) is responsible for causing the gastrointestinal symptoms of several C. perfringens food- and nonfood-borne human gastrointestinal diseases. The enterotoxin gene (cpe) is located on either the chromosome (for most C. perfringens type A food poisoning strains) or large conjugative plasmids (for the remaining type A food poisoning and most, if not all, other CPE-producing strains). In all CPE-positive strains, the cpe gene is strongly associated with insertion sequences that may help to assist its mobilization and spread. During disease, CPE is produced when C. perfringens sporulates in the intestines, a process involving several sporulation-specific alternative sigma factors. The action of CPE starts with its binding to claudin receptors to form a small complex; those small complexes then oligomerize to create a hexameric prepore on the membrane surface. Beta hairpin loops from the CPE molecules in the prepore assemble into a beta barrel that inserts into the membrane to form an active pore that enhances calcium influx, causing cell death. This cell death results in intestinal damage that causes fluid and electrolyte loss. CPE is now being explored for translational applications including cancer therapy/diagnosis, drug delivery, and vaccination.
Sensitivity and reliability of force tracking and joint-movement tracking scores in healthy subjects.

The purpose of this study was to examine the sensitivity and reliability of two tracking tests designed to measure control of handgrip force and finger movement. In one test, the subject exerts careful control of handgrip force on a dynamometer, which is interfaced with a computer, and attempts to guide a cursor as accurately as possible along a stationary target track displayed on the computer screen. In the second test, the subject attempts to trace a different target track by precise flexion-extension movement of the metacarpophalangeal joint of the index finger to which an electrogoniometer is attached. For both tests, the computer quantifies the subject's performance with an accuracy index. Fourteen healthy subjects participated in the force tracking test (FTT), which involved three pretest tracking trials, a 20-minute inactivity period, and three posttest trials. Thirteen different healthy subjects participated in the joint-movement tracking test (JMTT) using the same testing format. One-tailed, paired t tests of the pretest-posttest tracking scores showed significant ( p < .01) improvement in tracking accuracy for both the FTT and the JMTT. Additionally, intraclass correlation coefficients for both the pretest and the posttest trials showed acceptable reliability in the FTT and the JMTT. We concluded, for healthy subjects, that 1) these tracking tests are sensitive to small changes in force control and joint-movement control, and 2) the tracking scores are reliable. We believe that these tests could be very useful in documenting objectively the effects of treatment applied to the hand.
Pyribole evolution during tremolite synthesis from oxides

The formation mechanisms of tremolite in a time series of hydrothermal experiments at 850 °C and 6.1 kbar were studied using transmission electron microscopy (TEM), analytical TEM, and X- ray diffraction. The starting materials were unseeded mixtures of reagent-grade oxides. After the first 8 min of reaction, the synthesis products were diopside, enstatite, clinoenstatite, quartz, and minor C -centered and primitive monoclinic amphibole (13 wt% total). The compositions of the first- formed amphiboles vary considerably, from essentially pure cummingtonite (Ca/Mg = 0) to nearly ideal tremolite (Ca/Mg = 0.4). Three groupings of amphiboles with successively higher Ca/Mg ratios were identified, respectively 0.1, 0.22, and 0.35. Over a period of 97 h, the proportions of Mg-rich amphibole gradually decrease, and the average Ca/Mg ratios of all amphiboles steadily increase from about 0.22 to 0.35. Other changes include:(1) a decrease in the aspect ratio of amphibole crystals with increasing time; (2) a decrease in the number of non-amphibole chain multiplicity faults (CMFs), from early A′(2) values as low as 0.81 to a final value of 0.94; and (3) a distinct change in the rate of amphibole growth after 1 h of synthesis. These observations suggest that two mechanisms of amphibole formation are dominant:(1) formation of pyroxene modules with subsequent hydration and arrangement into the double-chain amphibole structure and (2) direct nucleation and growth of amphibole from hydrothermal solution. A third mechanism involving formation of talc-like modules, followed by their breakdown into double-chain modules, incorporation of Ca, and ordering into the amphibole structure, may also occur but probably only at the lamellar or unit-cell scale, because these syntheses were performed outside the stability field of talc.
Response of chickens to prolonged feeding of crude "toxic fat".

SummaryThese data would indicate that crude “toxic fat” has a marked effect on testicular development without appreciably affecting the development of secondary sex characters or growth rate. At levels of 0.5 and 1.0% “toxic fat,” reduced testicular development usually occurred in conjunction with hydropericardium and ascites. When the level of fat was reduced to 0.25%, hydro-pericardium and ascites was markedly reduced, whereas, retarded testicular development persisted. It would appear that in immature chickens testicular hypoplasia resulting from consumption of crude “toxic fat” is a more sensitive index of toxicity than is hydropericardium or ascites.