cssi/SciSciGPT-SciSciNet huggingface dataset:
Urban, Rural, and Regional Variations in Physical Activity.

Purpose: There is some speculation about geographic differences in physical activity (PA) levels. We examined the prevalence of physical inactivity (PIA) and whether US citizens met the recommended levels of PA across the United States. In addition, the association between PIA/PA and degree of urbanization in the 4 main US regions (Northeast, Midwest, South, and West) was determined. Methods: Participants were 178,161 respondents to the 2000 Behavioral Risk Factor Surveillance System (BRFSS). Data from 49 states and the District of Columbia were included (excluding Alaska). States were categorized by urban status according to the US Department of Agriculture. Physical activity variables were those commonly used in national surveillance systems (PIA ¼ no leisure-time PA; and PA ¼ meeting a PA recommendation). Results: Nationally, PA levels were higher in urban areas than in rural areas; correspondingly, PIA levels were higher in rural areas than in urban areas. Regionally, the urban-rural differences were most striking in the South and were, in fact, often absent in other regions. Demographic factors appeared to modify the association. Conclusion: The association between PA and degree of urbanization is evident and robust in the South but cannot be generalized to all regions of the United States. For the most part, the Midwest and the Northeast do not experience any relationship between PA and urbanization, whereas, in the West, the trend appears to be opposite of that observed in the South. indicated that prevalence of PIA (ie, no LTPA) was lowest in the central metropolitan settings (27%) and highest in rural settings (37%), with some variation by region. 2 Other reported research comparing activity levels in urban and rural settings suggests that adults living rurally tend to be less active than adults in urban centers, although results were mixed. 2-6 Four of the 5 studies cited did not consider regional variation, a factor that may be important for directing federal efforts to promote regular PA. If urban-rural differences exist in PA levels, are the differences consistent across the 4 major regions (South, West, Midwest, and Northeast) of the United States? Perhaps urban-rural differences can be explained by other known determinants of PA. For instance, people living in rural areas are more often of lower socioeconomic status (SES) than people living in urban areas, 7,8 and low SES is associated with lower levels of recommended PA. 1,9 Further, levels of PA vary by
Transmission traveltime tomography based on paraxial Liouville equations and level set formulations

We propose a new formulation for traveltime tomography based on paraxial Liouville equations and level set formulations. This new formulation allows us to account for multivalued traveltimes and multipathing systematically in the tomography problem. To obtain efficient implementations, we use the adjoint state technique and the method of gradient descent. Starting from some initial guess, we minimize a nonlinear energy functional by a Newton-type method. The required gradient is computed by solving one forward and one adjoint problem of the paraxial Liouville equations. Then the velocity model is updated iteratively by solving a Helmholtz equation with the computed gradient as the right-hand side. Numerical examples with and without added noise demonstrate that the new formulation is effective and accurate. To our knowledge, this is the first Eulerian approach to take into account all arrivals systematically in traveltime tomography.
Concomitant modulated superfluidity in polarized Fermi gases

Recent ground-breaking experiments studying the effects of spin polarization on pairing in unitary Fermi gases encountered mutual qualitative and quantitative discrepancies which seem to be a function of the confining geometry. Using numerical algorithms we study the solution space for a three-dimensional fully self-consistent formulation of realistic systems with up to ${10}^{5}$ atoms. A study of the three types of solutions obtained demonstrates a tendency toward metastability as the confining geometry is elongated. One of these solutions, which is consistent with Rice experiments at high trap aspect ratio, supports a state strikingly similar to the long sought Fulde-Ferrel-Larkin-Ovchinnikov state. Our study helps to resolve the long-standing controversy concerning the discrepancies between the findings from two different experimental groups and highlights the versatility of actual-size numerical calculations for investigating inhomogeneous fermionic superfluids.
Cell Division after Laser Microirradiation of Mitotic Chromosomes

MITOTIC chromosomes are now being studied by laser micro-irradiation which involves removing small areas (0.5–2 µm long) of either DNA or protein1. The cells are then observed in tissue culture or fixed and stained cytochemically. By these means, it has been possible to examine nucleolus production and function by selectively altering the nucleolar organizer region of chromosomes2. This type of investigation requires only that the cell completes mitosis and survives in interphase long enough for nucleolus formation and function to be assayed. Although much information can be gained from this type of short term experiment, there would be more scope for investigation if irradiated cells could be cultivated for long periods of time, and shown to be capable of undergoing subsequent mitoses.
Analysis of C–S–H gel and cement paste by small-angle neutron scattering

Abstract The role of small-angle X-ray and neutron scattering (SAXS and SANS) in the characterization of cement is briefly reviewed. The unique information obtainable from SANS analysis of C–S–H gel in hydrating cement is compared with that obtainable by other neutron methods. Implications for the nature of C–S–H gel, as detected by SANS, are considered in relation to current models. Finally, the application of the SANS method to cement paste is demonstrated by analyzing the effects of calcium chloride acceleration and sucrose retardation on the resulting hydrated microstructure.
Diffusion in silicon and the predictive power of ab-initio calculations

In a recent paper, Leung et al. [Phys. Rev. Lett. 83, 2351 (1999)] reported a theoretical study where they calculated the formation energy for a neutral silicon self-interstitial to be 4.9 eV using the diffusion quantum Monte Carlo (DMC) method, 50% (30%) higher than the LDA (GGA) result of usual ab-initio calculations. In this paper, we show that gap and finite-size corrections that have been proposed in the past might be able to explain this difference, as long as the defect levels for point defects are well known. We show that B-interstitial systems are more difficult in that sense, which seriously questions the generality of the approach.
Measure-valued solutions for a hierarchically size-structured population

We present a hierarchically size-structured population model with growth, mortality and reproduction rates which depend on a function of the population density (environment). We present an example to show that if the growth rate is not always a decreasing function of the environment (e.g., a growth which exhibits the Allee effect) the emergence of a singular solution which contains a Dirac delta mass component is possible, even if the vital rates of the individual and the initial data are smooth functions. Therefore, we study the existence of measure-valued solutions. Our approach is based on the vanishing viscosity method.
Hormonal induction of melanogenesis in hypophysectomized killifish (Fundulus heteroclitus).

THE experiments reported in this investigation were instigated by the accidental discovery, described below (Series XXI), that chronic treatment with prolactin stimulated melanogenesis in hypophysectomized killifish, Fundulus heteroclitus (Linn.). In discussing the complex problems involved, a distinction must be made between 1) physiological regulation of the state of concentration or dispersion of the melanophores, and 2) morphological processes of depigmentation, melanization, and new pigment cell formation. It has been repeatedly pointed out that the two phenomena appear to be interrelated (1, 2). Conditions which favor melanophore dispersion (illumination against a dark background, blinding) promote increased pigmentation and the development of new pigment cells. Conditions which favor aggregation of the melanin granules (illumination against a light background) retard or inhibit the development of melanophores and lead to a partial loss of pigment from cells already present. This is to be expected s...
Bonding in ClFn (n = 1−7) Molecules: Further Insight into the Electronic Structure of Hypervalent Molecules and Recoupled Pair Bonds†

As a result of new studies into the nature of hypervalent molecules, we identified a new type of bond called a recoupled pair bond. Hypervalency or hypercoordination was shown to arise by decoupling a pair of valence electrons, each of which becomes available to participate in a new bond. Energy must be expended to decouple an electron pair, so the first recoupled pair bond is weaker than the analogous covalent bond. However, the second bond, which involves a singly occupied antibonding orbital in the hypervalent fragment, is stronger than the analogous covalent bond. Following an initial study of SF(n) species (n = 1-6), the present work explores the ClF(n) (n = 1-7) series to further examine the explanatory usefulness of the recoupled pair bonding model. Optimized structures and energies of the ground and low-lying excited states of the ClF(n) molecules were determined by employing high level ab initio calculations [MRCI, CCSD(T)] with correlation consistent basis sets. Low-lying states that are due to recoupled pair bonding are found in ClF ((3)Pi) and ClF(2) ((2)A(1), (2)B(1), (2)A', (4)A(2)). The bond energies for F addition to form ClF(2), ClF(4), and ClF(6) were found to be much lower than those leading to ClF, ClF(3), and ClF(5). The same type of oscillation is observed in SF(n) species. The differences between ClF(n) and SF(n) reflect the fact that the 3s(2) and 3p(2) electron pairs are more strongly bound in Cl than in S. This behavior and other trends observed in the ClF(n) species demonstrate the improved predictive ability of the recoupled pair bonding model over other models for describing hypervalent bonding.
Sterol galactosides and sterol esters of the cotton bud

About 60% of the total sterols in the cotton bud appeared in the free state; the esterified sterol glycosides contained about 50% saturated fatty acids, largely palmitic acid; the principal unsaturated fatty acid was linolenic acid. β-Sitosterol was the major sterol in all classes of sterol derivatives. The sugar moiety of the esterified sterol glycosides and the sterol glycoside was galactose. Efforts are continuing to evaluate the minor sterols of cotton buds, some of which appear to be hydroxylated ecdysones, and to study their relationship to the development of the Boll weevil,Anthonomus grandis Boheman.
T4 RNA ligase

Abstract T4 RNA ligase is an indispensible tool for the synthesis and modification of RNA. Despite a clear understanding of its mechanism and its remarkably broad substrate specificity, its role in T4 infection is unknown.
Thermodynamic product retrieval methodology and validation for NAST-I

The National Polar-Orbiting Operational Environmental Satellite System (NPOESS) Airborne Sounder Testbed (NAST) consists of two passive collocated cross-track scanning instruments, an infrared interferometer (NAST-I) and a microwave radiometer (NAST-M), that fly onboard high-altitude aircraft such as the NASA ER-2 at an altitude near 20 km. NAST-I provides relatively high spectral resolution (0.25-cm-1) measurements in the 645–2700-cm-1 spectral region with moderate spatial resolution (a linear resolution equal to 13% of the aircraft altitude at nadir) cross-track scanning. We report the methodology for retrieval of atmospheric temperature and composition profiles from NAST-I radiance spectra. The profiles were determined by use of a statistical eigenvector regression algorithm and improved, as needed, by use of a nonlinear physical retrieval algorithm. Several field campaigns conducted under varied meteorological conditions have provided the data needed to verify the accuracy of the spectral radiance, the retrieval algorithm, and the scanning capabilities of this instrumentation. Retrieval examples are presented to demonstrate the ability to reveal fine-scale horizontal features with relatively high vertical resolution.
PLASMA I131-THYROXINE IN HYPOPHYSECTOMIZBD RATS INJECTED WITH RADIOIODIDE1

Hypophysectomized rats on low- or regular iodine diet were injected with large doses of I131 (250 to 1,000 μC), either with or without iodide carrier. Plasma was obtained 90 to 96 hours later, and dialyzed to remove inorganic iodide. Concentrated butanol extracts of plasma and of pancreatin digests of plasma were chromatographed, and distribution of I131 on the chromatograms was determined by counting sections of the paper in a scintillation well-counter, by use of an automatic paper scanner, or by radioautography. I131-thyroxine was detected in the plasma of the hypophysectomized rats but, in relation to the injected dose of I131, it was less than 1% of the amount observed in normal control rats injected with 1 or 5 μe. of I131. This low level of I131-thyroxine probably reflects a small residual thyroid function in hypophysectomized rats, although interpretation of the results was complicated by radiation damage to the thyroid.
Sustaining Soil Productivity in Response to Global Climate Change: Science, Policy, and Ethics

Sustaining Soil Productivity in Response to Global Climate Change: Science, Policy, and Ethics Thomas J. Sauer, John M. Norman, and Mannava V. K. Sivakumar, editors. Wiley, Hoboken, NJ, USA. 2011. 264 pp., US $199.95, hardcover. ISBN: 978-0-470-95857-5 Sustaining soil productivity to alleviate food
Neural networks based airfoil generation for a given Cp using Bezier–PARSEC parameterization

Abstract Determining the airfoil geometry from a given C p -distribution is an inverse problem of paramount importance specially in the context of variable geometry aerodynamic platforms. This work describes the implementation of artificial neural nets for the airfoil geometry determination. Instead of using full coordinates of the airfoil, Bezier–PARSEC 3434 parameters have been used to describe an airfoil. Some of these parameters have been determined using a Genetic Algorithm. In the second stage C p -distribution in terms of c l , c d and c m for 10 angles of attack has been input into three different neural nets for learning and then estimating the corresponding BP3434 parameters. Feed-forward backpropagation, Generalized regression and Radial basis neural nets have been trained and then compared in terms of performance and regression statistics. The work establishes the superiority of feed-forward backpropagation neural nets. The result is partly due to good function approximation properties of the neural architecture and partly due to the use of Bezier–PARSEC 3434 parameterization scheme.
A Probabilistic Expert System for Automatic Musical Accompaniment

This article presents methodology that allows a computer to play the role of musical accompanist in a nonimprovised musical composition for soloist and accompaniment. The modeling of the accompaniment incorporates a number of distinct knowledge sources including timing information extracted in real-time from the soloist's acoustic signal, an understanding of the soloist's interpretation learned from rehearsals, and prior knowledge that guides the accompaniment toward musically plausible renditions. The solo and accompaniment parts are represented collectively as a large number of Gaussian random variables with a specified conditional independence structure—a Bayesian belief network. Within this framework a principled and computationally feasible method for generating real-time accompaniment is presented that incorporates the relevant knowledge sources. The EM algorithm is used to adapt the accompaniment to the soloist's interpretation through a series of rehearsals. A demonstration is provided from J.S. B...
Measurements of thermoelectricity below 1°K.—II

Abstract IT is well known that metals such as copper may show anomalous resistive and thermoelectrio behaviour at low temperatures. It now seems clear (cf. Gold et al. 1960) that the large negative thermoelectric power which develops at temperatures of the order of 10°K to 20°K in certain specimens of the ‘pure’ metal or specially prepared dilute alloys must be attributed primarily to the presence of very small quantities of iron in solid solution. It also appears that other magnetic ions in solid solution will give rise to similar behaviour (cf. e.g. Jacobs and Schmitt 1959). It has been suggested (Schmitt 1956, cf. also Brailsford and Overhauser 1959) that, for example, the appearance of a maximum (and consequently also a minimum) in the electrical resistance at low temperatures can be explained in terms of scattering by magnetic impurity ions, if the spin degeneracy of the ground state is split and the electron scattering cross sections of the lower levels are higher than those of the upper levels. No ...
Ultra-early evaluation of intracerebral hemorrhage

The authors evaluate eight patients with intracerebral hemorrhage (ICH) who underwent computerized tomography (CT) within 2 1/2 hours after symptom onset and then again several hours later. The second CT scan was performed within 12 hours after onset for seven of the patients and 100 hours after onset for the eighth patient. In four patients, the second CT scan was obtained prospectively. The mean percentage of increase in the volume of hemorrhage between the first and second CT scans was 107% (range 1% to 338%). In each of the six patients with a greater than 40% increase in hemorrhage volume, neurological deterioration occurred soon after the first CT. A systolic blood pressure of 195 mm Hg or greater was recorded during the first 6 hours in five of the same six patients. The data from this study indicate that, in ICH, bleeding may continue after the 1st hour post-hemorrhage, particularly in patients with early clinical deterioration.
Improving the Education of Children Living in Poverty

Summary Richard Murnane observes that the American ideal of equality of educational opportunity has for years been more the rhetoric than the reality of the nation’s political life. Children living in poverty, he notes, tend to be concentrated in low-performing schools staffed by ill-equipped teachers. They are likely to leave school without the skills needed to earn a decent living in a rapidly changing economy. Murnane describes three initiatives that the federal government could take to improve the education of these children and increase their chances of escaping poverty. All would strengthen the standards-based reforms at the heart of the No Child Left Behind Act of 2001 (NCLB) by bracing the three legs on which the reforms rest: accountability, incentives, and capacity. Congress, says Murnane, should improve accountability by amending NCLB to make performance goals more attainable. The goals should emphasize growth in children’s skills rather than whether children meet specific test score targets. Congress should also amend NCLB to develop meaningful goals for high school graduation rates. Congress should strengthen states’ incentives to improve the education of low-income students. It should also encourage states to develop effective voluntary school choice programs to enable students who attend failing public schools to move to more successful schools in other districts. Finally, Congress should use competitive matching grants to build the capacity of schools to educate low-income children and the capacity of state departments of education to boost the performance of failing schools and districts. The grants would help develop effective programs to improve teaching and to serve students who do not fare well in conventional high school programs. Murnane estimates the annual cost of these three initiatives to be approximately $2.5 billion.
Applications of magnetic sensors for low cost compass systems

A method for heading determination is described that will include the effects of pitch and roll as well as the magnetic properties of the vehicle. Using solid-state magnetic sensors and a tilt sensor, a low cost compass system can be realized. Commercial airlines today use attitude and heading reference systems that cost tens of thousands of dollars. For general aviation, or small private aircraft, this is too costly for most pilot's budget. The compass system described here provides heading, pitch and roll outputs accurate to one degree, or better. The shortfall of this low-cost approach is that the compass outputs are affected by acceleration and turns. A solution to this problem is also presented.
A generalization of the ‘variable reference’ analogue/digital converter

This paper presents a general analysis of the ‘variable-reference’ A/D converter. The effects of varying the quantization point, and the reference-voltage to logic-level ratio are investigated. Considerable latitude in choosing resistance ranges can be obtained by manipulating these two parameters (which is important for integrated-circuit implementation). It is shown how the conversion time of this type has been improved by eliminating the usual input resistance by using a better reference configuration for the comparator. Comparison between the ladder-adder, current-summing resistors, and current switches for the feedback network are discussed in terms of improved conversion response time. The analysis is corroborated by experiment.
Matching of single‐strand breaks to form double‐strand breaks in DNA

Single-strand breaks (ssb) in opposite strands of DNA can be sufficiently near that a double-strand break (dsb) results. A theory is presented by which the maximum number h of base pairs which cannot prevent double-strand breakage can be determined from the rates of production of ssb and dsb. The assumptions required to derive the necessary equations as well as the range of validity of the equations are discussed in detail. In the experiments ssb and dsb were produced by x-irradiation in buffers which do not eliminate indirect effects and were measured by analytical ultracentrifugation. Values of h have been determined in low and high ionic strength and in low ionic strength over a range of temperatures. The values, 2.64 and 15.8, were obtained for high and low ionic strength, respectively.
THE CATHOLIC ORIGINS OF TOTALITARIANISM THEORY IN INTERWAR EUROPE

Totalitarianism theory was one of the ratifying principles of the Cold War, and remains an important component of contemporary political discourse. Its origins, however, are little understood. Although widely seen as a secular product of anticommunist socialism, it was originally a theological notion, rooted in the political theory of Catholic personalism. Specifically, totalitarianism theory was forged by Catholic intellectuals in the mid-1930s, responding to Carl Schmitt's turn to the “total state” in 1931. In this essay I explore the notion's formation and circulation through the Catholic public sphere in both France and Austria, where “antitotalitarianism” was born as a new form of the traditional Catholic animus against the nation state project.
Pedicled myocutaneous flaps in head and neck surgery

Reconstruction of head and neck surgical defects has undergone significant refinement in the last 2 decades. This modern era of reconstruction began with the introduction of the pectoralis major myocutaneous flap. This article attempts to summarize the anatomical and surgical aspects of this procedure. The principles of this reconstructive technique are applicable to other regional flaps used in head and neck reconstruction.
Buffer insertion in large circuits with constructive solution search techniques

Most existing buffer insertion algorithms, such as van Ginneken's algorithm, consider only individual nets. As a result, these algorithms tend to over buffer when applied to combinational circuits, since it is difficult to decide how many buffers to insert in each net. Recently, Sze, et al. (Sze, 2005) proposed a path-based algorithm for buffer insertion in combinational circuits. However their algorithm is inefficient for large circuits when there are many critical paths. In this paper, we present a new buffer insertion algorithm for combinational circuits such that the timing requirements are met and the buffer cost is minimized. Our algorithm iteratively inserts buffers in the circuit to improve the circuit delay. The core of this algorithm is simple but effective technique that guides the search for a good buffering solution. Experimental results on ISCAS85 circuits show that our new algorithm on average uses 36% less buffers and runs 3 times faster than Sze's algorithm.
Adipokines in Plasma and Breast Tissues: Associations with Breast Cancer Risk Factors

Background: Blood adipokines are associated with breast cancer risk; however, blood–breast adipokine correlations and factors that explain variation in adipokines are unknown. Methods: Plasma ( n = 155) and breast ( n = 85) leptin and adiponectin were assessed by immunoassays in women with no history of cancer. Multivariable-adjusted regression models were used to determine breast adipokine associations. Results: Through body mass index (BMI)-adjusted analyses, we initially observed positive plasma–breast correlations for leptin ( r = 0.41, P = 0.0002) and adiponectin ( r = 0.23, P = 0.05). The positive plasma–breast correlation for leptin was strongest among normal weight women ( r = 0.62), whereas the correlation for adiponectin was strongest among obese women ( r = 0.31). In multivariable models, adjusting for BMI, demographic, reproductive, and lifestyle factors, plasma leptin was not associated with breast leptin, and only the highest quartile of plasma adiponectin was associated with tissue levels. Of the risk factors investigated, those that contributed most to the variation in breast tissue adipokines were BMI and race for leptin, oral contraceptive use and smoking status for adiponectin. Conclusions: Although we report positive plasma–breast adipokine correlations overall, plasma adipokine concentrations may not be good surrogates for breast concentrations among all women. Predictors of breast adipokines vary, depending on subject characteristics, possibly explaining inconsistent epidemiologic results and they implicate differing pathways toward carcinogenesis. Impact: A clearer understanding of the relationships between plasma adipokines and their levels within the target organ is necessary to better understand the impact of these hormones on breast cancer risk. Future studies are needed to identify additional factors associated with breast adipokines in target tissues. Cancer Epidemiol Biomarkers Prev; 21(10); 1745–55. ©2012 AACR .
Adaptation on fluctuating fitness landscapes: speciation and the persistence of lineages.

Abstract The NK landscape model of adaptive evolution introduced by Kauffman & Levin (1987) is modified to simulate diversification of monophyletic lineages. Extinction probability is made a function of fitness, and speciation probability a function of the number of fitter one mutant neighbors, which is analogous to genetic potential. Dynamics of adaptive walks are measured as the total number of phenotypically defined species per generation. Changes in species number are described for static and varying landscapes. Persistence of lineages is incompatible with static fitness landscapes and requires that most component species do not reach adaptive optima. Differences in N : K ratios, and therefore in morphological integration, strongly affect speciation rates and could play a role in species sorting.
Muslim and Non-Muslim Differences in Female Autonomy and Fertility: Evidence from Four Asian Countries

The hypothesis that greater female power and autonomy produce lower fertility appears in many explanations of fertility differences and change (Dyson and Moore 1983; Cain Khanam and Nahar 1979; Basu 1992; Jeejeeboy 1995). This article examines the specific claim that the higher fertility of Muslims (compared to non-Muslims) can be traced to the lower level of power and autonomy (hereafter autonomy) afforded Muslim women. This lower autonomy reflects more rigid forms of patriarchy that characterize Muslim communities. Key elements of this argument "in here at the systemic institutional aggregate level" and thus require analysis at the community level (Smith 1989: 173-174; see also Balk 1994; Jeejeeboy and Sathar 2001). From a set of surveys of more than 50 communities in four Asian countries we identify 14 Muslim/non-Muslim pairwise community comparisons--that is pairs of communities that share many characteristics but differ in that one is predominately Muslim and the other predominately non-Muslim. Although not representative of any country or region these pairs of communities reflect substantial diversity of social and economic setting. Across most pairs of settings we show that Muslims have more children are more likely to want another child and if they want no more children are consistently less likely to be using contraception. We test whether these differences parallel differences in married womens autonomy. We use data collected for the purpose of investigating womens power autonomy and fertility: the Survey on the Status of Women and Fertility (SWAF). These data collected in 1993 and 1994 include a number of potentially relevant dimensions of womens autonomy: freedom of movement economic autonomy and exposure to intimidation/coercion. Direct measurement of multiple dimensions of autonomy avoids many of the criticisms of prior research on "womens status" and fertility (as discussed in Mason 1984 1996 1987). (excerpt)
Multicast performance analysis for high-speed torus networks

Overall efficiency of high-performance computing clusters not only relies on the computing power of the individual nodes, but also on the performance that the underlying network can provide to the computational application. Although modern high-performance networks, especially system area networks (SAN), have high unicast performance, they do not support multicast communication in hardware. This research experimentally evaluates the performance of various protocols for unicast-based and path-based multicast communication on high-speed torus networks. Software-based multicast performance results of selected algorithms on a 16-node Scalable Coherent Interface (SCI) torus are given. The strengths and weaknesses of the various protocols are illustrated in terms of startup and completion latency, CPU utilization, and link utilization and concurrency.
Analysis of the differential amplifier with an active load

The analysis and simulation of an emitter coupled differential amplifier with an active load is presented. In most books, the two halves of the differential amplifier are assumed to be identical. This assumption made to analyze the circuit leads to erroneous results. Here, the authors compare the simulation results with hand calculations to convince the readers about this very common error in the textbooks.
Enzyme Promiscuity: Engine of Evolutionary Innovation*

Catalytic promiscuity and substrate ambiguity are keys to evolvability, which in turn is pivotal to the successful acquisition of novel biological functions. Action on multiple substrates (substrate ambiguity) can be harnessed for performance of functions in the cell that supersede catalysis of a single metabolite. These functions include proofreading, scavenging of nutrients, removal of antimetabolites, balancing of metabolite pools, and establishing system redundancy. In this review, we present examples of enzymes that perform these cellular roles by leveraging substrate ambiguity and then present the structural features that support both specificity and ambiguity. We focus on the phosphatases of the haloalkanoate dehalogenase superfamily and the thioesterases of the hotdog fold superfamily.
PLEdestrians: a least-effort approach to crowd simulation

We present a new algorithm for simulating large-scale crowds at interactive rates based on the Principle of Least Effort. Our approach uses an optimization method to compute a biomechanically energy-efficient, collision-free trajectory that minimizes the amount of effort for each heterogeneous agent in a large crowd. Moreover, the algorithm can automatically generate many emergent phenomena such as lane formation, crowd compression, edge and wake effects ant others. We compare the results from our simulations to data collected from prior studies in pedestrian and crowd dynamics, and provide visual comparisons with real-world video. In practice, our approach can interactively simulate large crowds with thousands of agents on a desktop PC and naturally generates a diverse set of emergent behaviors.
Comparing biological measurements of vitamin C, folate, alpha-tocopherol and carotene with 24-hour dietary recall information in nonhispanic blacks and whites.

Abstract PURPOSE: To assess intake of several vitamins in preparation for a large cohort study investigating the effect of diet on risk of colon and prostate cancer. METHODS: The dietary intake of several vitamins were assessed using eight different 24-hour recalls and a 200-item food frequency questionnaire (FFQ) from each subject. Participants also attended a clinic where blood was drawn and body composition, weight, height, and blood pressure were measured. A total of 97 black and 96 nonhispanic white subjects participated. The levels of alpha-tocopherol, carotene, folate, and vitamin C in the blood were correlated with the dietary intakes as measured by both 24-hour recalls and FFQ. RESULTS: Correlations between blood levels and energy-adjusted dietary intake assessed by 24-hour recalls (with supplements) were as follows: carotene (adjusted for serum cholesterol): 0.47 and 0.55 in black and white subjects, respectively; alpha-tocopherol (adjusted for serum cholesterol): 0.61 (blacks) and 0.50 (whites); vitamin C: 0.22 (blacks) and 0.17 (whites); folate: 0.54 (blacks) and 0.55 (whites). Correlations between blood levels and FFQ indices were smaller in magnitude: 0.34 and 0.28 for carotene in black and white subjects, respectively, 0.37 and 0.56 for alpha-tocopherol (adjusted for serum cholesterol), 0.20 and 0.03 for vitamin C and 0.24 and 0.32 for folate. CONCLUSIONS: The correlations observed were generally of modest to moderate size and were similar to or larger than those reported by others. This is despite variations in absorption, metabolism, and excretion of the vitamins and suggests that both the 24-hour recalls and the FFQ contain valid information.
Differential effects of maximal- and moderate-intensity runs on plasma leptin in healthy trained subjects.

Abstract This study investigated the effect of different exercise bouts on plasma leptin response. Trained men ( n = 9) performed a short duration, maximal intensity (MAX) bout and a 60-min endurance run at ∼70% of maximal oxygen consumption (END). Blood was collected before, immediately after, 24 h after (24 h Post), and 48 h after exercise (48 h Post) for measurement of plasma leptin, insulin, and glucose. VO 2 max and percent body fat were 57.8 ± 2.1 mL ·1 kg −1 ·1 min −1 and 10.8 ± 1.5% (mean ± SEM), respectively. Energy expenditure was 197.5 ± 11.8 and 882.7 ± 14.4 kcal for MAX and END, respectively. Plasma leptin levels did not differ between time points for the MAX run. Leptin was significantly lower 48 h Post (2.2 ± 0.3 ng/mL) versus before, immediately after, and 24 h Post exercise (3.1 ± 0.3, 3.0 ± 0.3, and 2.5 ± 0.4 ng/mL, respectively) for END. Leptin tended to be lower at 24 h Post than before or immediately after exercise ( P = 0.10). Plasma insulin was lower 24 h Post- versus preexercise for the END, but was not correlated to changes in leptin levels. Plasma glucose levels did not change significantly during the endurance test. We found a delayed decrease in leptin at 48 h after an extended exercise session (900 kcal). Furthermore, this effect did not appear to be related to changes in insulin or glucose levels. Findings from this study address the effects of exercise on leptin, aiding in the evaluation of the impact of exercise and energy expenditure on plasma leptin concentrations in the prevention and treatment of obesity.
Analysis of Tritium Production in a Sphere of 6LiD with Oralloy Core Irradiated by 14-MeV Neutrons

Tritium production in a sphere of [sup 6]LiD with an Oralloy core irradiated by a central source of 14-MeV neutrons has been calculated and compared with experimental measurements. The experimental assembly consisted of an Oralloy sphere surrounded by three solid [sup 6]LiD concentric shells with ampoules of [sup 6]LiH and [sup 7]LiH located in several positions throughout the assembly. The Los Alamos Monte Carlo Neutron Photon Transport Code (MCNP) was used to calculate neutron transport through-out the system and tritium production in the ampoules. The MCNP calculations were three-dimensional and employed ENDF/B-V cross sections. The overall experimentally observed-to-calculated ratios of tritium production were 0.996 ([plus minus]2.5%) in [sup 6]LiH ampoules and 0.903 ([plus minus]5.2%) in [sup 7]LiH ampoules. Tritium production in a sphere of [sup 6]LiH without an Oralloy core has been reanalyzed using ENDF/B-V cross sections, and the results are reported. The reanalyzed observed-to-calculated values of tritium production were 1.053 ([plus minus]2.1%) in [sup 6]LiH and 0.999 ([plus minus]2.1%) in [sup 7]LiH. The foregoing several uncertainties do not include an estimated [lt]6% systematic error in the observed values.
Subspace models for functional MRI data analysis

The models used for analyzing functional MRI (fMRI) data have profound impact on the detection of active brain areas. In this paper temporal and spatial linear subspace models for fMRI analysis are reviewed. General principles of how such subspaces should be constructed in order to obtain optimal detection performance are discussed and it is shown that customarily employed subspace models can be significantly improved upon.
Genome-Wide Association Mapping of Quantitative Resistance to Sudden Death Syndrome in Soybean

Sudden death syndrome (SDS) is a serious threat to soybean production that can be managed with host plant resistance. To dissect the genetic architecture of quantitative resistance to the disease in soybean, two independent association panels of elite soybean cultivars, consisting of 392 and 300 unique accessions, respectively, were evaluated for SDS resistance in multiple environments and years. The two association panels were genotyped with 52,041 and 5,361 single nucleotide polymorphisms (SNPs), respectively. Genome-wide association mapping was carried out using a mixed linear model that accounted for population structure and cryptic relatedness. A total of 20 loci underlying SDS resistance were identified in the two independent studies, including 7 loci localized in previously mapped QTL intervals and 13 novel loci. One strong peak of association on chromosome 18, associated with all disease assessment criteria across the two panels, spanned a physical region of 1.2 Mb around a previously cloned SDS resistance gene (GmRLK18-1) in locus Rfs2. An additional variant independently associated with SDS resistance was also found in this genomic region. Other peaks were within, or close to, sequences annotated as homologous to genes previously shown to be involved in plant disease resistance. The identified loci explained an average of 54.5% of the phenotypic variance measured by different disease assessment criteria. This study identified multiple novel loci and refined the map locations of known loci related to SDS resistance. These insights into the genetic basis of SDS resistance can now be used to further enhance durable resistance to SDS in soybean. Additionally, the associations identified here provide a basis for further efforts to pinpoint causal variants and to clarify how the implicated genes affect SDS resistance in soybean.
A connection between the Lagrangian stochastic-convective and cumulant expansion approaches for describing solute transport in heterogeneous porous media

Abstract The equation describing the ensemble-average solute concentration in a heterogeneous porous media can be developed from the Lagrangian (stochastic–convective) approach and from a method that uses a renormalized cumulant expansion. These two approaches are compared for the case of steady flow, and it is shown that they are related. The cumulant expansion approach can be interpreted as a series expansion of the convolution path integral that defines the ensemble-average concentration in the Lagrangian approach. The two methods can be used independently to develop the classical form for the convection–dispersion equation, and are shown to lead to identical transport equations under certain simplifying assumptions. In the development of such transport equations, the cumulant expansion does not require a priori the assumption of any particular distribution for the Lagrangian displacements or velocity field, and does not require one to approximate trajectories with their ensemble-average. In order to obtain a second-order equation, the cumulant expansion method does require truncation of a series, but this truncation is done rationally by the development of a constraint in terms of parameters of the transport field. This constraint is less demanding than requiring that the distribution for the Lagrangian displacements be strictly Gaussian, and it indicates under what velocity field conditions a second-order transport equation is a reasonable approximation.
The Effects of Mother’s Marital Status on Adolescent and Young Adult Health and Economic Well-Being Among African Americans

This article explores the effects of being raised by married parents during childhood on health and well-being in adolescence and young adulthood in a longitudinal sample of African Americans. This study aims to address the following three questions: Does childhood with married patients lead to better health and well-being during adolescence? Does childhood with married patients lead to better health and well-being in young adulthood? Do the health effects of childhood with married patients differ for male and female? The authors found modest direct effects of childhood exposure to marriage on health for females. Having at least some childhood marriage exposure was also associated with several positive health behaviors. There is modest evidence that marriage bestows health benefits for children and that these benefits endure into young adulthood.
Evolution of alternative and constitutive regions of mammalian 5'UTRs

Alternative splicing (AS) in protein-coding sequences has emerged as an important mechanism of regulation and diversification of animal gene function. By contrast, the extent and roles of alternative events including AS and alternative transcription initiation (ATI) within the 5'-untranslated regions (5'UTRs) of mammalian genes are not well characterized. We evaluated the abundance, conservation and evolution of putative regulatory control elements, namely, upstream start codons (uAUGs) and open reading frames (uORFs), in the 5'UTRs of human and mouse genes impacted by alternative events. For genes with alternative 5'UTRs, the fraction of alternative sequences (those present in a subset of the transcripts) is much greater than that in the corresponding coding sequence, conceivably, because 5'UTRs are not bound by constraints on protein structure that limit AS in coding regions. Alternative regions of mammalian 5'UTRs evolve faster and are subject to a weaker purifying selection than constitutive portions. This relatively weak selection results in over-abundance of uAUGs and uORFs in the alternative regions of 5'UTRs compared to constitutive regions. Nevertheless, even in alternative regions, uORFs evolve under a stronger selection than the rest of the sequences, indicating that some of the uORFs are conserved regulatory elements; some of the non-conserved uORFs could be involved in species-specific regulation. The findings on the evolution and selection in alternative and constitutive regions presented here are consistent with the hypothesis that alternative events, namely, AS and ATI, in 5'UTRs of mammalian genes are likely to contribute to the regulation of translation.
A critique of one- and two-dimensional models of boundary layer clouds with a binned representations of drop microphysics

A variety of models of boundary layer turbulence are increasingly being coupled to binned representation of cloud-drop spectra for the purpose of studying cloudy boundary layers and aerosol-cloud-drop interactions. A critique of one dimensional models shows that extant methods of coupling bin-microphysical models to the turbulence model omit important terms involving covariances of perturbation quantities. Errors incurred from the omission of these terms are significant: cloud-drop activation is not properly represented, and the initial stages of precipitation growth may be retarded in horizontally inhomogeneous boundary layers. If the promise of one-dimensional models is ever to be realized, some means of accurately representing these terms must be developed. Because large-scale models often have grid-spacings much larger than typical cloud-eddy-scale circulations, attempts to couple them to more detailed microphysical representations will also suffer from the problems discussed in the context of one-dimensional models. This should provide added motivation for improving the representation of microphysical processes on the sub-grid scale. An analysis of two-dimensional eddy-resolving models closed on the basis of energy inertial range arguments illustrates that the lack of an energy cascade in two dimensions results in increasingly vigorous circulations as the model's grid-mesh is refined. Two-dimensional model simulations can display significant variability to vanishingly small differences in the initial conditions, and drizzle rates vary by as much as 30% when total water concentrations are increased by only 1%. Such sensitivities make it difficult to constrain the models given the degree of uncertainty that characterizes measurements of state variables in clouds. Despite some inconsistencies in the formulation of their closure terms, two-dimensional models are at least able to qualitatively represent the interaction of the large-eddies and microphysical processes in boundary layer flows. For this reason they appear to be useful, not as surrogates for reality, but rather as a means for further refining hypotheses about the physical system thereby increasing the chances that such hypotheses can be tested observationally.