cssi/SciSciGPT-SciSciNet huggingface dataset:
Simulation of beef cattle production systems in the Llanos of Colombia—part I. Methodology: An alternative technology for the tropics

Abstract A simulation model was developed to study voluntary forage intake, energy requirements for maintenance, liveweight change and calving rate of grade Zebu cows in the Llanos of Colombia. Multiplicative correction factors were fitted to intake and maintenance requirement prediction equations researched from the literature to account for reduced intake due to sparse regrowth of recently burned native savanna and to conditions of mineral deficiency, increased intake and decreased maintenance requirement during periods of high compensatory gain during the rainy season, and increased intake and maintenance requirement due to the effects of lactation and gestation. A frequency distribution was constructed relating liveweight at time of mating to subsequent calving rate, and this was used to simulate the calving rates of cow herds in the Llanos. Use of the model would allow prediction of the amount of improved pasture or supplemental feed that would be necessary to raise calving rates in a particular herd to an acceptable level, defined as at least three calves per cow every four years. The model was fitted by computer and was then run on programmable calculators. This type of simulation is suited to regions of the world in which computer time is expensive or unavailable. Verifications, validations and experimentation with the model are presented in a companion paper.
Drought-induced changes in water relations in broom snakeweed (Gutierrezia sarothrae) under greenhouse- and field-grown conditions

Abstract Pressure-volume analyses were done on a half-shrub broom snakeweed ( Gutierrezia sarothrae ) subjected to different soil water regimes under pot- and field-grown conditions. Under pot and field conditions, water deficit decreased water and osmotic potentials. In the severely droughted pot-grown, osmotic potential at full turgor (П 100 ) decreased by 0.44 MPa due to reduced symplastic volume, the result of a decreased leaf turgid to dry weight ( TW/DW ) ratio. A reduction of 0.86 MPa in П 100 was observed in the field-grown plants subjected to the first drought cycle, but increased cell wall elasticity occurred in the second drought cycle. The lowered П 100 was attributed to osmotic adjustment and reduced symplastic volume. High cell wall elasticity in the second drought cycle led to a greater water loss and tissue desiccation. It is concluded that osmotic adjustment, increased apoplastic water fraction and more rigid tissue are important dehydration-avoidance mechanisms in broom snakeweed.
Multivariable system identification for integral controllability

Integral controllability is necessary and sufficient for a multivariable model to be usable in a decoupling controller with integral action that can be arbitrarily detuned without jeopardizing closed-loop robust stability. The design of experiments for identification of integral controllable models is challenging, because it must satisfy cumbersome eigenvalue inequalities involving a coupling between the real system and its model. To address this challenge, an optimization-based mathematical framework is developed that characterizes efficient identification experiments ensuring integral controllability. The proposed framework recovers well known experiment designs but also produces new ones of both theoretical and practical interest. Such designs are expressed either analytically or as a result of numerical optimization and are demonstrated in a number of examples. These designs can be easily implemented in industrial practice. By combining additional objectives or constraints of interest, the proposed framework can further serve as a basis for new experiment designs in future work.
Constructing entire functions by quasiconformal folding

We give a method for constructing transcendental entire functions with good control of both the singular values of f and the geometry of f. Among other applications, we construct a function f with bounded singular set, whose Fatou set contains a wandering domain.
Thermodynamic approach to oxygen delivery in vivo by natural and artificial oxygen carriers

Abstract Oxygen is a toxic gas, still indispensable to aerobic life. This paper explores how normal physiology uses the physico-chemical and thermodynamic characteristics of oxygen for transforming a toxic gas into a non toxic indispensable metabolite. Plasma oxygen concentration is in the range of 10 − 5 M, insufficient to sustain metabolism. Oxygen carriers, present in blood, release oxygen into plasma, thereby replacing consumed oxygen and buffering PO 2 near their P 50 . They are the natural cell-bound carriers, like hemoglobin inside red cells, myoglobin inside myocytes, and artificial cell-free hemoglobin-based oxygen carriers (HBOC) dissolved in plasma. Metabolic oxygen replacement can be defined as cell-bound and cell-free delivery. Cell-bound delivery is retarded by the slow diffusion of oxygen in plasma and interstitial fluids. The 40% hematocrit of normal blood compensates for the delay, coping with the fast oxygen consumption by mitochondria. Facilitated oxygen diffusion by HBOCs corrects for the slow diffusion, making cell-free delivery relatively independent from P 50 . At all oxygen affinities, HBOCs produce hyperoxygenations that are compensated by vasoconstrictions. There is a strict direct correlation between the rate of oxygen replacement and hemoglobin content of blood. The free energy loss of the gradient adds a relevant regulation of tissues oxygenation. Oxygen is retained intravascularly by the limited permeability to gases of vessel walls.
Differential responses to odorant analogs after recovery from nerve transection

We previously found that exposure-induced increase in odor sensitivity involves, at least in part, the olfactory epithelium. We did this by exposing mice to 5 alpha-androst-16-en-3-one (androstenone) and measuring changes in the epithelium. Past research showed that sensitivity to androstenone also could be induced by exposing individuals to 4-(4',4'-dimethylcyclohexyl)-2-methylcyclohexanone (DMCMC), a structural and functional analog of androstenone. What remained unknown is whether structural and/or functional odorant analogs share peripheral components. In the current work, we used a well-established model to disconnect the olfactory epithelium from the olfactory bulbs (BNX) to disrupt mechanisms underlying olfactory coding (when the afferents reinnervate the bulb, they do not synapse in their original glomeruli), and to examine the effects of disruption and restoration on exposure-induced odor sensitivity. In this study, we determined whether analogs of androstenone, viz., 5 alpha-androstan-3-one (androstanone) and DMCMC, could induce sensitivity to androstenone after BNX. Results demonstrate that exposure to either androstanone or DMCMC can induce sensitivity to androstenone in control mice. Different results were observed in mice that had recovered from bilateral BNX. Exposure to androstanone for 10 days immediately after surgery increased sensitivity to androstenone; however, exposure to DMCMC did not. These results suggest that androstanone and DMCMC, although apparent perceptual analogs of androstenone, may be using different pathways of olfaction within the central nervous system (CNS).
A strategy toward the synthesis of C13-oxidized cembrenolides

An efficient strategy for the construction of C13-oxidized cembrenolides is reported. Central to this strategy is the installation of the C13 hydroxyl group prior to cembrane macrocyclization (via formation of the C1–C2 bond), allowing access to both C13 alcohol epimers. The orientation of the C13 alcohol was found to influence the cyclization mode of the cembranolide scaffold upon furan oxidation, leading to motifs reminiscent to bipinnatolide F, bielschowskysin, and verrillin.
Gas Sensing with High-Resolution Localized Surface Plasmon Resonance Spectroscopy

We report the first inert gas sensing and characterization studies based on high-resolution localized surface plasmon resonance (HR-LSPR) spectroscopy. HR-LSPR was used to detect the extremely small changes (<3 × 10−4) in bulk refractive index when the gas was switched between He(g) and Ar(g) or He(g) and N2(g). We also demonstrate submonolayer sensitivity to adsorbed water from exposure of the sensor to air (40% humidity) versus dry N2(g). These measurements significantly expand the applications space and characterization tools for plasmonic nanosensors.
A simple system for the preliminary evaluation of infectivity and pathogenesis of insect virus in a nontarget estuarine shrimp

Abstract Biological control agents (biorationals) are increasingly important in pest control concepts. Certain insect viruses, particularly the baculoviruses (nuclear polyhedrosis viruses), are considered to have potential as biological pesticides and could be used widely in the environment. Therefore, test animals must be selected and methods and laboratory systemsdeveloped to evaluate the safety of these agents to nontarget species. A simple laboratory system has been designed and used to determine risks of infectivity and pathogenicity of an insect Baculovirus , originally isolated from the Alfalfa looper, Autographa californica , to a nontarget arthropod, the grass shrimp, Palaemonetes vulgaris , by dietary exposure. This laboratory method also permits evaluation of other microbial biorationals against nontarget aquatic species, and provides an inexpensive standardized procedure of safety testing. Results from this study indicated that histopathological, ultrastructural, and serological methods used provided no evidence that experimental exposure to the virus in our test system caused viral infection or related pathogenicity in the grass shrimp.
Phenomenon of Local Skin Reactivity to Bacterial Filtrates: Its Relation to Anaphylatoxins, Forssman Antibodies and Serum Toxicity

In the phenomenon of local skin reactivity, the state of reactivity is elicited, exclusively, by certain bacterial filtrates. Conversely, in addition to the bacterial filtrates, certain antigen +antibody combinations and possibly, with less frequency, some human and guinea pig serums, agar and starch, may be endowed with provocative potency, i.e., induce severe hemorrhagic reactions in sites prepared with bacterial filtrates. This paper embodies studies on the relation of provocative factors of the phenomenon under consideration to anaphylatoxins, Forssman antigen+antibody complexes and certain toxic serums.
Physiological ecology of nitrogen fixing blue-green algal crusts in the upper-subalpine life zone

Blue-green algal (cyanobacterial) crusts composed of nitrogen fixing Nostoc commune Voucher ex Born. et Flah. and Tolypothrix conglutinata var. colorata Ghose were studied in the upper-subalpine life zone, Mission Mountain Wilderness, Montana. Rates of ethylene production were highest in the submerged shoreline crusts, lower for exposed crusts pioneering rocky shorelines and lowest in the Carex meadow. Nitrogenase activity (acetylene reduction technique) was constant between 200–285% crust moisture content (wet/dry weight) and then rapidly declined to 0 between 200–140%. Optimal temperatures for ethylene production by illuminated cells was between 20–30° C for T. conglutinata, 20° C for N. commune and about 25° C in darkness for both species. Nitrogenase activity by T. conglutinata in culture was unaffected by repeated freeze-thaw treatments whereas N. commune was severely inhibited. In contrast, N2-ase activity of these two species in an intact crust was unaffected by repeated freeze-thaw treatments. Application of nitrogen-free growth medium to intact crusts increased nitrogenase activity by 3.7 times implying that these were mineral deficient under field conditions. Photosynthesis was light saturated at 125 μmol-m−2.s−1 whereas nitrogenase activity was light independent for cells with carbohydrate reserves. When carbohydrate reserves were reduced by 8 h incubation in darkness, between 1–3 h of illumination were required to restore nitrogenase activity to 80% of the maximum rate. Biochemical pathway inhibitor studies employing DCMU, MFA, and CCCP showed that oxidative metabolism was the source of reductant for acetylene reduction. Tetrazolium precipitation in heterocysts paralleled acetylene reduction activity in the inhibitor treated cells.
Collective behaviour of an ensemble of forced duffing oscillators near the 1:1 resonance

Abstract Preserving the beam size (or equivalently the emittance) is a primary aim of accelerator physics. Here we study the effect on the emittance of power supply ripple in the guiding magnetic fields. The collective behaviour of forced Duffing oscillators is the natural model to understand this phenomenon. We consider the case when the external frequency is near the linearized natural frequency and nonlinearity and forcing are small. The method of averaging reduces the problem to an autonomous system. A coarse grained long time limit of the phase space density and the rate of approach to this limit are discussed in terms of the autonomous system. The equilibrium density and the rate of approach to equilibrium depend crucially on the detuning parameter e.g. the equilibration time for phase space averages is much shorter above the bifurcation value of the detuning parameter than it is below. We find the frequencies which lead to the largest emittance growth in three different forcing regimes (weak, moderate and relatively large) and also characterize the dependence of emittance growth on forcing amplitude in these regimes.
Teicoplanin and rifampicin singly and in combination in the treatment of experimental Staphylococcus epidermidis endocarditis in the rabbit model

Teicoplanin and rifampicin were evaluated as single and combined agents in the treatment of endocarditis due to Staphylococcus epidermidis in the rabbit model. Rabbits were treated for ten days and the number of bacteria in vegetations determined. At the end of ten days the geometric mean number of bacteria in the vegetations were 5.53 X 10(8), 6.68 X 10(6). 1.10 X 10(4), 2.57 X 10(1) cfu/g of vegetation for control, teicoplanin, rifampicin, and teicoplanin plus rifampicin groups respectively. The MIC and MBC values of the S. epidermidis isolates were 0.78 mg/l for teicoplanin and less than or equal to 0.10 mg/l for rifampicin. In the rifampicin treated group three post-treatment isolates of S. epidermidis tested exhibited marked resistance to rifampicin with MIC and MBC values greater than or equal to 200 mg/l. Teicoplanin and rifampicin were both effective as single agents in the clearance of S. epidermidis from the bloodstream. Rifampicin was more effective than teicoplanin in the clearance of S. epidermidis from vegetations but teicoplanin in combination with rifampicin was more effective than either drug alone.
A computational tool to optimize ligand selectivity between two similar biomacromolecular targets

Algorithms for a new computer program designed to increase ligand-receptor selectivity between two proteins are described. In this program ligand-receptor selectivity is increased by functional modifications to the ligand so as to increase the calculated binding affinity of it to one protein and/or decrease the calculated binding affinity of it to the other protein. The structure of the ligand is modified by selective replacement of atoms and/or functional groups in silico based on a specific set of steric and/or hydropathic complementarity rules involving atoms and functional groups. Relative binding scores are calculated with simple grid-based steric penalty, hydrogen bond complementarity, and with the HINT score model. Two examples are shown. First, modifying the structure of the ligand CB3717 is illustrated in a number of ways such that the binding selectivity to wild type L. casei thymidylate synthase or its E60Q mutant may be improved. Second, starting with a non-selective lead compound that had been co-crystallized with both plant and mammalian 4-hydroxyphenylpyruvate dioxygenases, new compounds (similar to selective ligands discovered by screening) to improve the selectivity of (herbicidal) inhibitors for the plant enzyme were designed by the program.
Predictability and uncertainty in flow–structure interactions

Abstract Direct numerical simulation advances in the field of flow–structure interactions are reviewed both from a deterministic and stochastic point of view. First, results of complex wake flows resulting from vibrating cylindrical bluff bodies in linear and exponential sheared flows are presented. On the structural side, non-linear modeling of cable structures with variable tension is derived and applied to the problem of a catenary riser of complex shape. Finally, a direct approach using Polynomial Chaos to modeling uncertainty associated with flow–structure interaction is also described. The method is applied to the two-dimensional flow–structure interaction case of an elastically mounted cylinder with random structural parameters subject to vortex-induced vibrations.
Statistics of martensitic nucleation

Abstract Nucleation statistics, incorporating the particle size effects and the temperature effects, of martensitic transformations in ZrO2-containing ceramics and in Fe-Ni alloys was analyzed. A phenomenological potency distribution of nucleating defects, of the form of (excess driving force)2, was found. Using a simple model of long range nucleating defects, of the type of a dislocation wall, a theoretical potency distribution was predicted. The model was in good agreement with the experimental data and with the phenomenological form, over a broad range of excess driving force. A universal potency distribution for intrinsic, pre-existing defects thus became apparent Experimental evidence was found, in literature and in new data reported here, that both the size effects and the universal potency distribution will be violated when nucleation is extrinsically induced, especially in very small particles or in strain-induced transformations. An essential distinction in the origin of nucleation, as reflected in nucleation statistics, can thus be drawn for classification of martensitic nucleation.
The global environment of business

One of the first tenets of international business (IB) is that it spans multiple disciplines. Yet driven by the need to publish in specialist journals or by the disciplinary expertise of individual authors, most studies at best pay lip service to this aspect of the field. It is perfectly possible to do deep and meaningful IB research through a single disciplinary lens. However, using the analytical tools of multiple disciplines can make for richer analysis (Agrawal & Hoetker, 2007). Frederick Guy's ambitious book is an attempt at such an inquiry.
The Strength of Strong Ties: Media Multiplexity, Communication Motives, and the Maintenance of Geographically Close Friendships

Media multiplexity proposes that tie strength drives patterns of media use, more so than the reverse. This study examined connections between friendship quality, CMC motives, and relational maintenance. Participants (N = 350) completed measures of maintenance behaviors, CMC motives, friendship satisfaction and solidarity. Number of channels was weakly related to solidarity. Satisfaction and solidarity had relationships with some of the motives and all of the maintenance behaviors. Support and distance motives were positively and negatively related to maintenance behaviors, respectively.
An Initial Assessment of Prehistoric Ceramic Production and Exchange in Northern Yoruba, North Central Nigeria: Results of Ceramic Compositional Analysis

Instrumental neutron activation analysis (INAA) was employed on 201 ceramic and clay samples fromthe Igbomina region of northern Yoruba in Nigeria. Ceramic data were obtained from 13 settlement sites spread over four Igbomina localities whose dates range between A.D. 1400 and A.D. 1800, and five raw clay samples from riverbeds and modern potters located in the Igbomina culture area. Quantitative analysis of the INAA data resulted in identification of four ceramic compositional groups that can be attributed to specific locales within the region. These results indicate that ceramics were moved within and among various Igbomina geographic areas and villages as well Ilorin (a Yoruba center located northeast of Igbomina).Results generated from this analysis indicate the tremendous potential for examining regional interaction in Yorubaland immediately before and during the Old Oyo period (fifteenth to the eighteenth century A.D.), a time of sociopolitical and settlement change.
Relationship of intracloud lightning radiofrequency power to lightning storm height, as observed by the FORTE satellite

[1] Prior studies have noted a strongly nonlinear enhancement of lightning flash rates with increasing cloud height. Here we report a related observation, of a tendency for increasing intracloud-discharge radiofrequency-emission power for increased height of the electrified cloud. The FORTE satellite's radio-frequency-receiver payload has performed extensive recordings of electromagnetic emissions of lightning discharges. The most commonly occurring such emission arises from intracloud electrical breakdown and is usually recognizable by a pulse followed by a delayed echo from the ground reflection. We have used other systems of lightning monitors to provide source locations for an extended data set of FORTE intracloud-discharge signals. The interpulse separation within each pulse pair yields the discharge height above the reflective ground. The storm in which the pulse occurs usually provides many (at least 50) recorded events. From the pattern of these events' heights, we can usually infer a capping height, which serves as an upper bound on the lightning discharge heights for that storm. We find that there is a strong statistical increase of effective radiated power of intracloud discharges, for increasing capping height of the parent storm. Thus a future satellite-based lightning monitor that triggers on only the most intense radiofrequency emissions will be strongly selective for electrified storms with very deep vertical development. Such storms are also indicated in severe convective weather.
Analytic and intuitive perceivers in the form constancy task

Two alternatives for the method used by Ss to solve the form constancy task were tested by varying the range of angles to which rectangles were rotated. Results indicate that response consistency improves as the angles become less discriminable, contrary to Koffka’s invariance hypothesis. Thus, an alternative intuitive mode of perceiver operation is supported.
The Effect of Hydrostatic Pressure on the Curie Point of Barium Titanate Single Crystals

The influence of hydrostatic pressure on the Curie temperature of BaTi${\mathrm{O}}_{3}$ single crystals has been investigated. With increasing pressure a linear shift of the Curie point towards lower temperature is observed with a slope of -5.8\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}3}$ degree/atmos. This information allows us to calculate the change of the specific heat and of the compressibility at the Curie point according to Ehrenfest's relation. Thus it is possible to relate the pressure effect to the change of the lattice constant. The decrease of the Curie temperature with shrinking lattice constant is nearly the same as that observed when Sr ions are substituted for Ba in the titanate crystal. In addition, measurements have been made on the influence of pressure on the first order transition point near 0\ifmmode^\circ\else\textdegree\fi{}C.
Genetic Determinants of Feline Leukemia Virus-Induced Multicentric Lymphomas

Three discrete forms of feline leukemia virus (FeLV)-associated lymphoma have been described clinically: (1) thymic, (2) alimentary, and (3) multicentric. The most common and best-characterized lymphomas are of T-cell origin, generally occurring in the thymus. These tumors typically contain mature T-cells, involve the activation of a distinctive set of proto-oncogenes, and contain FeLV proviruses whose long terminal repeat (LTR) sequences contain tandemly repeated enhancers. Previous studies of a small group of extrathymic, multicentric lymphomas implicated a different set of genetic determinants. The present study expands those observations by examining the lineage of origin, the involvement of proto-oncogenes, and the structure of LTR and env gene sequences in a set of 11 natural, extrathymic lymphomas of the multicentric type. A pattern of genetic events associated with FeLV-positive multicentric lymphomas emerges from this analysis that is clearly distinct from the pattern associated with thymic lymphomas. The tumors do not contain T-cells or B-cells, as evidenced by the germ line organization of TCR beta and IgH loci. Proto-oncogenes strongly implicated in T-cell lymphomagenesis are not involved in these tumors. Rather, a distinct set of proto-oncogenes may be involved. Most striking is the repeated occurrence of an FeLV isolate whose LTR and env gene bear unique sequence elements.
A multi-mesh MPM for simulating the meshing process of spur gears

Abstract A numerical scheme is presented to simulate the meshing process of spur gears, based on the material point method (MPM). To allow engagements at successive contact points and subsequent separation between neighboring gear teeth, a contact/sliding/separation procedure in a multi-mesh environment without using master/slave nodes is proposed so that the no-slip contact constraint inherent in the existing MPM can be released. Individual drive members rotate around corresponding axes, through which simulated angular velocity transmission is in good agreement with the analytical solution. It appears from the simulation results presented here that the multi-mesh MPM could become a robust spatial discretization tool for gear design problems that involve large rotation, contact/sliding and separation.
A conceptual quantitative model for prevention of work-related carpal tunnel syndrome (CTS)

Abstract In this paper the authors present a pathogenic mechanism of carpal tunnel syndrome (CTS) and a heuristic conceptual model to assess the musculoskeletal stress of manual work for the purpose of establishing quantitative guidelines to prevent work-related CTS. The model is based on the concept that the frictional energy of manual work within the wrist initiates local tenosynovitis as and CTS, the value of the product should not exceed a limit derived from the population-based threshold. Reliable, validated techniques should be used for gathering data on the stress factors of manual work for the purpose of establishing quantative guidelines to control and prevent work-related CTS.
Accurate visual measurement of three-dimensional moving patterns

Human observers discriminated relative three-dimensional distances in simple patterns of motion parallax with an acuity similar to vernier acuity under comparable conditions. Accurate visual measures of three-dimensional distance can be derived from the structural invariance of patterns undergoing perspective transformations.
Synthesis of (Ca, Ce3+, Ce4+)2Ti2O7: a pyrochlore with mixed-valence cerium

Abstract Pyrochlore with mixed-valence Ce was synthesized by firing and annealing Ce(NO3)4, TiO2, and Ca(OH)2 with a stoichiometry of CaCeTi2O7 at 1300 °C. The product contains Ce-pyrochlore, Ce-rich perovskite, CeO2 (cerianite), and minor CaO. Electron energy-loss spectroscopy (EELS) revealed both Ce4+ and Ce3+ in the Ce-pyrochlore with a Ce4+ to total Ce (Ce4+/ΣCe) of 0.80 giving ( Ca 0.87 Ce 0.21 3 + Ce 0.86 4 + ) Ti 2.05 O 7 . Cerium in the perovskite and cerianite is dominated by Ce3+ and Ce4+, respectively. High-resolution transmission electron microscope (HRTEM) images show that the boundary between Ce-pyrochlore and Ce-rich perovskite is semi-coherently bonded. The orientational relationship between the neighboring Ce-pyrochlore and Ce-rich perovskite is not random. Ce-pyrochlore (CaCeTi2O7) is a chemical analogue for CaPuTi2O7, which is a proposed ceramic waste form for deposition of excess weapons-usable Pu in geological repositories. It is postulated, based on the presence of Ce3+ in the Ce-pyrochlore, that neutron poisons such as Gd can be incorporated into the CaPuTi2O7 phase.
Undergraduate mathematics majors’ writing performance producing proofs and counterexamples about continuous functions

In advanced mathematical thinking, proving and refuting are crucial abilities to demonstrate whether and why a proposition is true or false. Learning proofs and counterexamples within the domain of continuous functions is important because students encounter continuous functions in many mathematics courses. Recently, a growing number of studies have provided evidence that students have difficulty with mathematical proofs. Few of these research studies, however, have focused on undergraduates’ abilities to produce proofs and counterexamples in the domain of continuous functions. The goal of this study is to contribute to research on student productions of proofs and counterexamples and to identify their abilities and mathematical understandings. The findings suggest more attention should be paid to teaching and learning proofs and counterexamples, as participants showed difficulty in writing these statements. More importantly, the analysis provides insight into the design of curriculum and instruction that may improve undergraduates’ learning in advanced mathematics courses.
Impact of bariatric surgery on female reproduction

Objective To evaluate the current literature on the impact and potential mechanisms of surgical weight loss on female reproduction, with a focus on changes in reproductive hormone profile, fertility status, measures of ovarian reserve, efficacy of oral contraception, sexuality, and pregnancy. Design Appraisal of articles relevant to surgical weight loss and female reproduction. Result(s) The altered reproductive hormone profile associated with morbid obesity seems to reverse, either partially or totally, after surgical weight loss. Although bariatric surgery seems to improve fertility status and many of the complications associated with obesity in pregnancy, it may be linked to oral contraceptive failure. Although mullerian-inhibiting substance is a direct measure of ovarian reserve, its level changes with obesity and after surgical weight loss. There is a decrease or no change in the risk of miscarriage after bariatric surgery. An improvement in sexual function may follow dramatic surgical weight reduction; however, the possibility of a detrimental influence afterward can occur. Conclusion(s) The increasing popularity of bariatric surgery in reproductive-age women calls for greater clinician awareness of its impact on female reproduction.
Statistical Methods to Analyze Adverse Events Data of Randomized Clinical Trials

The adverse events data of randomized clinical trials are often analyzed based on either crude incidence rates or exposure-adjusted incidence rates. These rates do not adequately account for an individual patient's profile of adverse events over the study period when an individual may remain in the trial after experiencing one or more events (i.e., occurrence of multiple events of the same kind or different kinds). Moreover, the required statistical assumptions (e.g., constant hazard rate over time) for valid estimates of incidence rates are not likely to be met in practice by adverse events data of clinical trials. A nonparametric approach called the mean cumulative function (MCF) provides a valid statistical inference on recurrent adverse event profiles of drugs in randomized clinical trials. The estimate involves no assumptions about the form of MCF. To demonstrate the applicability and utility of the MCF approach in clinical trial datasets, an adverse event dataset obtained from a clinical trial is analyzed in this article. As compared to the crude or exposure-adjusted incidence rates of adverse events, the MCF estimates facilitate more understanding of safety profiles of a drug in a randomized clinical trial.
Examination of temperature-induced `gel-sol' transformation of α-actinin/cross-linked actin networks by static light scattering

Abstract We studied the gel-sol transformation of F-actin/α-actinin solutions. Cross-linking of actin filaments by α-actinin shows a temperature-dependent increase in light scatter signal, (I)T. Higher F-actin/α-actinin molar ratios, rAα as well as increases in F-actin concentration, [A], and reduction of actin filament lengths, rAG, augment the maximal light intensity, I and shift the gel-sol transition point, Tg to higher temperatures. This behavior is interpreted in terms of the model developed by Tempel, M., Isenberg, G. and Sackmann, E. (1996) (Physical Review E 54, 1802–1810) based on the percolation theory. Using the temperature-dependent binding model of this theory allows instant prediction of the equilibrium constant, K for F-actin/α-actinin solutions at temperatures T
Anatomy of a nanoscale conduction channel reveals the mechanism of a high-performance memristor.

By employing a precise method for locating and directly imaging the active switching region in a resistive random access memory (RRAM) device, a nanoscale conducting channel consisting of an amorphous Ta(O) solid solution surrounded by nearly stoichiometric Ta(2) O(5) is observed. Structural and chemical analysis of the channel combined with temperature-dependent transport measurements indicate a unique resistance switching mechanism.
Interleukin-33 upregulation in peripheral leukocytes and CNS of multiple sclerosis patients

Multiple sclerosis (MS) is an immune-mediated demyelinating disease of the central nervous system (CNS). Here we document for the first time that the cytokine IL-33 is upregulated in both the periphery and the CNS of MS patients. Plasma IL-33 was elevated in MS patients compared to normal subjects and a three-month treatment of MS patients with interferon β-1a resulted in a significant decrease of IL-33 levels. Similarly, stimulated cultured lymphocytes and macrophages from MS patients had elevated IL-33 levels compared to normal subjects. In parallel, the transcription factor NF-κB that mediates IL-33 transcription was also elevated in leukocytes of MS patients. IL-33 was elevated in normal-appearing white matter and plaque areas from MS brains and astrocytes were identified as an important source of IL-33 expression in the CNS. In summary, IL-33 levels are elevated in the periphery and CNS of MS patients, implicating IL-33 in the pathogenesis of MS.
Calculus of variations on time scales: weak local piecewise Crd1 solutions with variable endpoints

Abstract A nonlinear calculus of variations problem on time scales with variable endpoints is considered. The space of functions employed is that of piecewise rd-continuously Δ-differentiable functions (C1prd). For this problem, the Euler–Lagrange equation, the transversality condition, and the accessory problem are derived as necessary conditions for weak local optimality. Assuming the coercivity of the second variation, a corresponding second order sufficiency criterion is established.
Asymptotic behavior of the fixed-angle on-shell quark scattering amplitudes in non-Abelian gauge theories

In this paper we find the asymptotic behavior of the fixed-angle on-shell quark-quark scattering amplitude in non-Abelian gauge theories in the limit of very large center-of-mass energy ..sqrt..s . We sum the perturbation series to all orders in the coupling constant and all powers of lns, but ignore terms which are suppressed by a power of s order by order in perturbation theory. In the s..-->..infinity limit the amplitude vanishes as exp(-..cap alpha.. lns ln lns), where ..cap alpha.. is a constant. The phase of the amplitude is shown to be free from infrared divergences. Hence the phase is a perturbatively calculable function and may provide important tests of QCD.
Data Falsification in Clinical Trials

This article uses an infamous case of data falsification in clinical research as a starting point for a deeper analysis of some of the motivations and obligations that could encourage misconduct in a clinical setting. The article argues that the use of alternative, less rigid experimental designs and protocols could help lessen the pressures on researchers to falsify clinical data pertaining to patient records, and that it is worth considering alternative designs to benefit patients and help promote integrity in medical research.
Analysis of chaotic instabilities in boiling systems

An analytic model for the investigation of non-linear dynamics in boiling systems has been developed. This model is comprised of a nodal formulation that uses one-dimensional homogeneous equilibrium assumptions for diabatic two-phase flow, a lumped parameter approach for heated wall dynamics, and point neutron kinetics for the consideration of nuclear feedback in a boiling water reactor (BWR) loop. This model indicates that a boiling channel coupled with a riser may experience chaotic oscillations. In contrast, a boiling channel without a riser that is subjected to a constant pressure drop (i.e. a parallel channel) may undergo a supercritical bifurcation (i.e. may experience a limit cycle), but chaos was not found. Flow instabilities in a two-phase natural circulation loop have been verified using the model presented in this paper. The predictions of the effects of the channel inlet resistance, outlet resistance and liquid level in the downcomer agree with the data of Kyung and Lee. Finally, an analysis of nuclear-coupled density-wave instabilities in a simplified BWR (SBWR) was performed. Significantly, even for low pressure conditions, a simplified SBWR appears to be stable during start-up and normal operations; however, a limit cycle may occur for abnormal operating conditions.
Influence of a Kentucky Flood-Control Reservoir on the Tailwater and Headwater Fish Populations

Abstract An impoundment on the Green River, Kentucky, altered the fish community below the dam and in the unregulated river above the reservoir. Reservoir species apparently migrated both down-stream and upstream out of the reservoir and were abundant in both areas. Abundance in the tailwaters of two species common in the reservoir—white crappies (Pomoxis annularis) and gizzard shad (Dorosoma cepedianum)—was positively correlated with the volume of discharge. Redhorse (Moxostoma sp.) and catfish (Ictaluridae) were less abundant in the tailwaters than above the reservoir. Post-impoundment reductions in abundance of minnows (Cyprinidae), redhorse, and catfish in the tailwaters appeared to be related to lower water temperatures caused by discharge of water from the hypolimnion. Use of a stream station above a reservoir to represent the pre-impoundment fish community will lead to erroneous conclusions for species that migrate extensively upstream after becoming established in the reservoir. However, compariso...
The Editor's Roundtable: Endothelial dysfunction in cardiovascular disease.

r. Friedewald has no relevant financial relationships to isclose. Dr. Giles has received honoraria for consulting rom Boehringer Ingelheim, Ridgefield, Connecticut; Brisol-Myers Squibb, New York, New York; Sanofi-Aventis, ridgewater, New Jersey; Forest/Sankyo, New York, New ork; Novartis, East Hanover, New Jersey; and Pfizer, New ork, New York. Dr. Giles has received grant research upport as a principal investigator from Novartis; and the ational Institutes of Health, Bethesda, Maryland (Univerity of Medicine and Dentistry of New Jersey, Newark, New ersey). Dr. Pool has no relevant financial relationships to isclose. Dr. Yancy has received honoraria for research, onsulting, and speaking from GlaxoSmithKline, Research riangle Park, North Carolina; Medtronic, Minneapolis, innesota; and Scios, Mountain View, California. Dr. ancy has received honoraria for consulting from Novartis. r. Roberts has received honoraria for speaking from erck, Whitehouse Station, New Jersey; Schering Plough, enilworth, New Jersey; Pfizer; AstraZeneca, Wilmington, elaware; and Novartis.
Organo-silica nano-particles used in ultrahigh-pressure liquid chromatography

A simple one-step process was used to synthesize uniform, spherical organosilica nano-particles containing octadecyl moieties. These nano-particles, having a diameter of 670 nm, were slurry packed into fused-silica capillary tubes of 50 μm internal diameter and tested for use in ultrahigh-pressure liquid chromatography (UHPLC) at inlet pressures of about 50,000 psi (∼3,500 bar), providing for the use of HPLC with nano-particle packed columns. The retention characteristics of a column packed with the organo-nano-particles were shown to be stable under acidic (pH 11) conditions. Fast analysis times and relatively high separation efficiencies (∼500,000 plates m−1) were obtained under the conditions used.
Catalytic gasification of graphite by bimetallic particles

Abstract Controlled-atmosphere electron microscopy was used as a microanalytical probe of Pt: Ir (80:20 atomic ratio) on single-crystal graphite. The test reaction for this probe was the catalytic gasification in 5 Torr oxygen. Continuous observation of samples prepared by vacuum evaporation of a Pt: Ir alloy wire onto graphite showed the particles propagated shallow channels emanating from edges and steps on the graphite surface for temperatures near 670 °C; increasing the temperature up to 950 °C led to increased channeling activity; near 1000 °C the catalytic gasification ceased; finally, at higher temperatures (ca. 1030 °C), channeling recommenced and particle mobility was observed. This behavior is characteristic of Ir particles, and no particles showing Pt behavior were seen. Thus, Pt: Ir on single-crystal graphite forms alloy particles, the surface of which is enriched with Ir in an oxidizing atmosphere. A similar series of experiments performed with a Pt: Rh alloy showed that the Rh component preferentially segregates to the surface of the particles.
Microbially enhanced oil recovery from unconsolidated limestone cores

Abstract The enhanced recovery of residual oil from unconsolidated carbonate cores using microorganisms was examined in model cores packed with chips of Viola limestone. Vibrio aspartigenicus strain GSP‐1, an acid producer, and Bacillus licheniformis strain JF‐2, a surfactant producer, were used as the test microorganisms. The primary hypothesis tested was that microbial treatment of a packed core system would result in the recovery of residual oil from the carbonate test system. After three treatments, 39–44% of the residual oil‐in‐place was recovered from packed core systems after treatment with strain GSP‐1. Two treatments with strain JF‐2 resulted in a 27% recovery of the residual oil‐in‐place. Modification of the core matrix was indicated by the presence of calcium in the core effluents and significant amounts of carbonate fines found in the dissected cores, presumably caused by dissolution of the carbonate matrix by microbial acid end products of metabolism (microbial matrix acidizing). These result...
Size distribution of atmospheric giant particles.

Abstract The size distribution of atmospheric giant particles in the range 5–100 μm radius was measured at three locations in Washington State using a rotary inertial impactor. The size distribution was continuous at the different locations. A significant change in the slope of the dN dlog r vs. r plot of the size distribution generally occurred between 30 and 40 μm radius. The slope B ( dN dlog r = Ar −B ) in the 5–25 μm radius range averaged 2.3 while in the 40 to 100 μm radius range B averaged 6.7. A complete atmospheric aerosol size distribution for the 0.01–100 μm radius range was obtained by combining thermal precipitator (0.01–1 μm) and inertial impaction (5–100 μm) data. It followed from the calculation of the atmospheric aerosol mass distribution (assuming spherical particles of unit density) that approximately 20 per cent of the total mass was in particles of less than 1 μm radius, 35 per cent in the 1–10μm range, 45 per cent in the 10–50 μm range, and less than 1 per cent in the greater than 50 μm radius range.
Nuclear, chemical and biological characterization of formation histories of ironstones from several sites in Southern California: Dominant role of bacterial activity

Abstract Pebble-sized sandstone concretions, cemented by iron and manganese oxides, are found in several semi-arid regions in the world. Although recognized for a long time, their formation mechanisms have not yet been constrained from scientific studies. We have made extensive studies of the chemical composition, cosmogenic 10 Be and radiogenic U/Th concentrations, and biological fossils in ironstones from six sites in southern California. The ironstones exhibit appreciable enrichments of Mn, Zn, Mg, Ti, Fe, U, Th, and fossil bacteria. In addition to elemental data, we report here first observations of radionuclides, U, Th, K, and concentrations of cosmogenic 10 Be which we show are an excellent indicator of precipitation amounts. Our data favor the model that the ironstones formed within sandy beach ridges during wetter climates following dry climates during which aeolian sediment was added to the beach ridges. Iron, Mn, Zn and other trace element-rich leachates from the dust layers nurtured and accelerated bacterial activity in the beach ridges down to depths of a few meters, as first suggested by Abbott (1981). Our observations of trace-element enrichments and bacterial fossils support the model proposed by Abbott and underscore the fact that the ironstones are principally a product of bacterial activity, which concentrates the leachates in a narrow layer within the beach ridges. The extreme alternating dry/wet climatic conditions which existed in the past in southern California led to the formation of ironstone concretions within the ancient beach ridges, which provided suitable host mineralogy for their formation. The time periods represented by the ironstones from the six sites presumably cover the past ∼ 1 my. The recent surface explorations on the surface of Mars by the rovers SPIRIT and OPPORTUNITY (Squyres et al., 2006), showed that similar to southern California, extreme climatic conditions existed on Mars in its early history. It therefore seems that studies of ironstones may provide useful clues to the evolution of soils on Mars in such extreme climates, and possibly even provide criteria to evaluate whether any bacterial activity was present at that time.
Exponentially decreasing collision-broadened line shapes

We obtain asymptotic approximations to the collision-broadened line shape by the method of steepest descent. Exponentially decreasing line shapes result when the phase at the saddle point has an imaginary part. Averaging over a thermal distribution of velocities is shown to substantially affect the line shape.
The role of point defects in ion-bombardment-enhanced and dopant-enhanced grain growth in silicon thin films

Abstract Both ion bombardment and the addition of electronically active dopants lead to enhancements in the rate of normal grain growth in polycrystalline silicon films. Models have been developed which explain these phenomena in terms of their effect on the vacancy concentrations at grain boundaries. Taken together, the models suggest a general relation between the enhanced grain growth rate and non-equilibrium point defect concentrations. To test this idea, grain growth experiments have been carried our with polycrystalline silicon films subject to both ion bombardment and doping. The experiments, which indicate that the contributions to the enhanced grain growth rate by doping and ion bombardment are approximately additive, are consistent with this general relationship.