cssi/SciSciGPT-SciSciNet huggingface dataset:
Certifiable program generation

Code generators based on template expansion techniques are easier to build than purely deductive systems but do not guarantee the same level of assurance: instead of providing “correctness-by-construction”, the correctness of the generated code depends on the correctness of the generator itself. We present an alternative assurance approach, in which the generator is extended to enable Hoare-style safety proofs for each individual generated program. The proofs ensure that the generated code does not “go wrong”, i.e., does not violate certain conditions during its execution.The crucial step in this approach is to extend the generator in such way that it produces all required annotations (i.e., pre-/postconditions and loop invariants) without compromising the assurance provided by the subsequent verification phase. This is achieved by embedding annotation templates into the code templates, which are then instantiated in parallel by the generator. This is feasible because the structure of the generated code and the possible safety properties are known when the generator is developed. It does not compromise the provided assurance because the annotations only serve as auxiliary lemmas and errors in the annotation templates ultimately lead to unprovable safety obligations.We have implemented this approach and integrated it into the AutoBayes and AutoFilter program generators. We have then used it to fully automatically prove that code generated by the two systems satisfies both language-specific properties such as array-bounds safety or proper variable initialization-before-use and domain-specific properties such as vector normalization, matrix symmetry, or correct sensor input usage.
A new kind of graph coloring

A proper k-coloring C1, C2,...,Ck of a graph G is called strong if, for every vertex u ∈ V(G), there exists an index i ∈ {1, 2,...,k} such that u is adjacent to every vertex of Ci. We consider classes SCOLOR(k) of strongly k-colorable graphs and show that the recognition problem of SCOLOR(k) is NP-complete for every k ≥ 4, but it is polynomial-time solvable for k = 3. We give a characterization of SCOLOR(3) in terms of forbidden induced subgraphs. Finally, we solve the problem of uniqueness of a strong 3-coloring.
Modeling granular soils liquefaction using coupled lattice Boltzmann method and discrete element method

Abstract In this paper, a novel coupled pore-scale model of pore-fluid interacting with discrete particles is presented for modeling liquefaction of saturated granular soil. A microscale idealization of the solid phase is achieved using the discrete element method (DEM) while the fluid phase is modeled at a pore-scale using the lattice Boltzmann method (LBM). The fluid forces applied on the particles are calculated based on the momentum exchange between the fluid and particles. The presented model is based on a first principles formulation in which pore-pressure develops due to actual changes in pore space as particles׳ rearrangement occurs during shaking. The proposed approach is used to model the response of a saturated soil deposit subjected to low and large amplitude seismic excitations. Results of conducted simulations show that at low amplitude shaking, the input motion propagates following the theory of wave propagation in elastic solids. The deposit response to the strong input motion indicates that liquefaction took place and it was due to reduction in void space during shaking that led to buildup in pore-fluid pressure. Soil liquefaction was associated with soil stiffness degradation and significant loss of interparticle contacts. Simulation results also indicate that the level of shaking-induced shear strains and associated volumetric strains play a major role in the onset of liquefaction and the rate of pore-pressure buildup.
Instability in diffusing fluid layers

A small perturbation analysis is carried out to determine the stability of a fluid containing two layers of diffusing solutes in a common solvent and acted upon by a uniform gravitational field. It is found that instability can arise even though the unperturbed diffusion does not lead to the formation of a density inversion within the fluid.
Use of l -cysteine for minimization of inorganic Hg loss during thermal neutron irradiation

Thermal neutron irradiation experiments performed with cellulose-based l-cysteine-treated and untreated Hg standards showed Hg losses of 59–81% for untreated standards but only about a 0.2% loss for treated standards. These results and others for multielement standards showed that Hg loss is highly dependent on total mass and placement of materials in the irradiation vessel and that distribution of volatilized Hg was fairly uniform throughout the sample-containing region of the vessel. Polyethylene trapped volatile Hg much more efficiently than cellulose and a multielement standard containing inorganic Se selectively trapped Hg lost from a co-irradiated multielement standard containing Hg.
The origins of the spiral theory of phyllotaxis

In September 1829, at the Convention of German Scientists and Physicians at Heidelberg, two young botanists, Carl Schimper and Alexander Braun, presented papers outlining a new theory describing the distribution of leaves around an axis, or, to use the botanical term, phyllotaxis.' The theory broke with past writings on the subject in two essential respects: it postulated that all leaf distribution should be understood as a spiral and, more importantly, that all possible spiral variations may be defined by the fractions of several mathematical series well known to students of the theory of numbers. Although their fellow botanists applauded the originality and elegance of the spiral theory, not all of them would accept it in the form that Schimper and Braun proposed. Auguste and Louis Bravais wanted to revise the theory for empirical reasons, suggesting some numerical values slightly different from those of Schimper and Braun.2 Julius Sachs mistrusted the theory for epistomological reasons; to him it seemed to lack a satisfactory causal explanation and was too heavily laden with fanciful numerology.3 Though twentieth-century scientists have paid
Cholesterol-rich diets have different effects on lipid peroxidation, cholesterol oxides, and antioxidant enzymes in rats and rabbits.

Abstract The objective of this study was to compare the effect of cholesterol feeding of rats and rabbits. The levels of lipid peroxidation products and oxysterols in the plasma of the two species plus the antioxidant enzyme activities in the liver and erythrocytes were measured to explain their different susceptibilities to atherosclerosis. Our study showed that rats are less susceptible than are rabbits to the atherogenic effect of a cholesterol-rich diet because of differences in lipid peroxidation products as well as antioxidant enzymes activities in their livers. In rabbits, cholesterol feeding produced severe hypercholesterolemia (43-fold increase) and increased plasma and liver lipid peroxidation. Total as well as the individual oxysterol contents of 7α-, 7β-hydroxycholesterol, α-epoxy, β-epoxycholesterol, cholestanetriol, 7-keto, and 27-hydroxycholesterol significantly increased in the plasma of hypercholesterolemic (HC) rabbits. Erythrocyte glutathione peroxidase (GSH-Px) activity significantly decreased whereas catalase activity significantly increased in HC rabbits. In rats cholesterol feeding increased the plasma cholesterol only twofold and had no effect on plasma or liver lipid peroxidation. Only 7α- and 7β-hydroxycholesterol increased and no change was observed in any of the antioxidant enzymes activity in the erythrocytes. Although cholesterol feeding caused a 10-fold increase of liver cholesterol as ester in both rats and rabbits, the antioxidant enzyme GSH-Px and catalase activities in the liver significantly increased in rats but significantly decreased in rabbits. The increase of GSH-Px and catalase activities in the liver of cholesterol fed rats could have a protective role against oxidation, thus preventing the formation of lipid peroxidation and oxysterols.
The State of Differentiation of Cultured Human Keratinocytes Determines the Level of Intercellular Adhesion Molecule-1 (ICAM-1) Expression Induced by γ Interferon

Inducing the expression of ICAM-1(CD54) on the surface of epidermal keratinocytes is an important step, in initiating leukocyte interaction with the epidermis. We studied tile effect of keratinocyte differentiation and of drugs used to treat epidermal inflammation on the induction of this important adhesion molecule. Cell membrane expression of ICAM-1 in cultured human keratinocytes was analyzed using both immunofluorescence and FACS analysis of staining with anti-ICAM-1 monoclonal antibody and was correlated with markers of keratinocyte differentiation. Cell-surface ICAM-I expression was induced by 7 interferon in all culture conditions, but was significantly greater (p Anti-inflammatory glucocorticoids had no effect on ICAM-1 expression in cultured human keratinocytes, even at suboptimal γ interferon doses (5 U/ml). β-estradiol, on the other hand, mimicked the Etretin effect, increasing both IFN induction of ICAM-1 expression and K5 staining in more differentiated keratinocytes in 0.15 and 1.0 nM calcium, but not in those in 0.03 mM calcium. Both Etretin and β-estradiol decreased staining of involucrin, a marker of terminal differentiation, supporting the proposition that in this experimental system these drugs suppress keratinocyte differentiation. The enhanced ICAM-1 induction in keratinocytes with a basal level of differentiation correlates with the in vivo effects of interferon on ICAM-1 and may be a principal determinant in the patterns of ICAM-1 seen in inflammatory skin diseases.
Signaling through cyclin D-dependent kinases

Research over the past quarter century has identified cyclin D-dependent kinases, CDK4 and CDK6, as the major oncogenic drivers among members of the CDK superfamily. CDK4/6 are rendered hyperactive in the majority of human cancers through a multitude of genomic alterations. Sustained activation of these protein kinases provides cancer cells with the power to enter the cell cycle continuously by triggering G1-S-phase transitions and dramatically shortening the duration of the G1 phase. It has also become clear, however, that CDK4/6 effectively counter cancer cell-intrinsic tumor suppression mechanisms, senescence and apoptosis, which must be overcome during cell transformation and kept at bay throughout all stages of tumorigenesis. As a central 'node' in cellular signaling networks, cyclin D-dependent kinases sense a plethora of mitogenic signals to orchestrate specific transcriptional programs. As the complexity of the cellular signaling network regulated by these oncogenic kinases unfolds, much remains to be learned about its architecture, its dynamics and the consequences of its perturbation.
Chronic extrinsic denervation after small bowel transplantation in rat jejunum: Effects and adaptation in nitrergic and non-nitrergic neuromuscular inhibitory mechanisms.

Background. Extrinsic denervation of the transplanted small bowel could play a substantial role in motor dysfunction of the transplanted gut. We attempted to determine the effect of chronic extrinsic denervation on intestinal contractility. Methods. Jejunal longitudinal muscle strips were obtained from rats 1 week and 8 weeks after (1) syngeneic small bowel transplantation, (2) ischemia/reperfusion, or (3) gut transection/reanastomosis. Nonoperated rats (naive controls) and sham-operated rats (sham controls), 1 week after celiotomy/gut manipulation, served as controls. We evaluated the effects of exogenous nitric oxide, increasing doses of cholinergic and adrenergic agonists, and electrical field stimulation (EFS) in the presence or absence of NG-monomethyl-l-arginine, methylene blue, tetraethylammonium, or tetrodotoxin. Results. Spontaneous contractile activity (X ± SEM), when compared with the naive controls (11.3 ± 2.0 g·5 min/mg), was increased in all 4 groups at 1 week (15.9 ± 10 to 19.4 ± 2 g·5 min/mg; P ≤ .03 each) but not at 8 weeks postoperatively. The inhibition of contractile activity by nitric oxide was increased in small bowel transplantation in naive controls at 8 weeks to 80% ± 10% versus 50% ± 7% (P < .02). EFS induced an inhibition of contractile activity that was tetraethylammonium- and tetrodotoxin-sensitive but NG-monomethyl-l-arginine- and methylene blue-insensitive; the maximal EFS-induced inhibition was increased at 1 week and 8 weeks but only in the small bowel transplantation groups to 103% ± 5% and 95% ± 7%, respectively, versus 72% ± 8% in naive controls (P ≤ .05). Conclusions. Increased inhibition of contractile function after small bowel transplantation lasts at least 8 weeks and is mediated by changes in the enteric neuromuscular unit caused by extrinsic denervation. (Surgery 2001;129:478-89.)
The Pigskin and the Picture Tube: The National Football League's First Full Season on the CBS Television Network

This article describes the efforts of the Columbia Broadcasting System to telecast the National Football League's 1956 season on the CBS Television Network. The network established a pattern of mul...
Hierarchical power management in disruption tolerant networks using traffic-aware optimization

Recent efforts in Disruption Tolerant Networks (DTNs) have shown that mobility can be a powerful means for delivering messages in highly-challenged environments. DTNs are wireless mobile networks that are particularly useful in sparse environments where the density of nodes is insufficient to support direct end-to-end communication. Unfortunately, many mobility scenarios depend on untethered devices with limited energy supplies. Without careful management, depleted energy supplies will degrade network connectivity and counteract the robustness gained by mobility. A primary concern is the energy consumed by wireless communication, and in particular the energy consumed in searching for other nodes to communicate with. In this paper we examine a hierarchical radio architecture in which nodes are equipped with two complementary radios: a long-range, high-power radio and a short-range, low-power radio. In this architecture energy can be conserved by using the low-power radio to discover communication opportunities with other nodes and waking the high-power radio to undertake data transmission. We develop a generalized power management framework for controlling the wake-up intervals of the two radios. In addition, we show how to incorporate knowledge of the traffic load, and we devise approximation algorithms to control the sleep/wake-up cycling to provide maximum energy conservation while discovering enough communication opportunities to handle that load. We evaluate our schemes through simulation under various mobility scenarios. Our results show that our generalized power management scheme can tune wake-up intervals of the two radios to balance energy efficiency and delivery performance. Also, when traffic load can be predicted, our approximation algorithms reduce energy consumption from 60% to 99% compared to no power management.
Improving Estimates of Economic Parameters by Use of Ridge Regression with Production Function Applications

Ridge regression is a promising alternative to deletion of relevant variables for alleviating multicollinearity and can provide smaller mean square error estimates than unbiased methods such as OLS. However, ridge estimates can also be unreliable and misleading under certain conditions. To avoid erroneous conclusions from ridge regression, some prior knowledge about the true regression coefficients is helpful. A theorem on expected bias implies that ridge regression will give much better results for some economic models, such as certain production functions, than for others because of smaller expected bias.
Effects of Grain-Size Distribution on Time Dependence of the Remanent Magnetization in Thin Film Recording Media

In this paper we present a model incorporated with a Gamma distribution of the grain sizes for the time dependence of magnetization. Performances of writing process and long-term information storage are evaluated in terms of the grain-size distributtion, applied reverse field, frequency constant and temperature. Qualitative agreement is obtained between numerical calculation and experiment for the time decay of the magnetization in thin film recording media.
Intense-field photodissociation of H2+: Comparison of time-dependent and time-independent calculations.

The decay of the initial bound-state population and the fragment kinetic-energy distribution produced by the intense-field photodissociation of ${\mathrm{H}}_{2}^{+}$ are calculated using both a time-dependent and a time-independent method. The time-dependent method calculates the time evolution of the wave function describing ${\mathrm{H}}_{2}^{+}$ interacting with a classical time-dependent laser field by repeated application of a short-time propagator. The time-independent method constructs a wave packet using the energy eigenstates of the total molecule-plus-field Hamiltonian with the field expressed as a superposition of quantized photon number states. Specifically, the wave packet represents an initial bound-state wave function of the field-free molecule subjected to a coherent photon state that simulates the classical radiation field at t=0. The subsequent decay of this nonstationary state can be viewed as a laser-induced predissociation of field-dressed bound states into field-dressed continuum states with various numbers of photons absorbed from the field. For very rapid dissociation, the decays of the initial bound-state population calculated by both methods are in good agreement if a square pulse shape is used and the initial phase of the time-dependent interaction is averaged over. The fragment kinetic-energy distributions calculated by the two methods are in good agreement if they are compared at times when there is unit probability for dissociation. For slow to moderately rapid dissociation, averaging over the initial phase of the field is unnecessary because there is no rapid decay component. However, this also implies that the wave function must be propagated over many time steps before complete dissociation is achieved. To avoid this, we describe a procedure for fitting a short-time line-shape function, which represents incomplete dissociation of the initial state, to the nondepletion-limit fragment kinetic-energy distribution. A parametric fit to the calculated distributions allows us to extract very accurate estimates of decay rates, ac Stark shifts, and branching ratios.
Towards proximity pattern mining in large graphs

Mining graph patterns in large networks is critical to a variety of applications such as malware detection and biological module discovery. However, frequent subgraphs are often ineffective to capture association existing in these applications, due to the complexity of isomorphism testing and the inelastic pattern definition. In this paper, we introduce proximity pattern which is a significant departure from the traditional concept of frequent subgraphs. Defined as a set of labels that co-occur in neighborhoods, proximity pattern blurs the boundary between itemset and structure. It relaxes the rigid structure constraint of frequent subgraphs, while introducing connectivity to frequent itemsets. Therefore, it can benefit from both: efficient mining in itemsets and structure proximity from graphs. We developed two models to define proximity patterns. The second one, called Normalized Probabilistic Association (NmPA), is able to transform a complex graph mining problem to a simplified probabilistic itemset mining problem, which can be solved eficiently by a modified FP-tree algorithm, called pFP. NmPA and pFP are evaluated on real-life social and intrusion networks. Empirical results show that it not only finds interesting patterns that are ignored by the existing approaches, but also achieves high performance for finding proximity patterns in large-scale graphs.
Moments of the probability distribution for noisy maps.

The effect of small-amplitude additive Gaussian white noise on maps with periodic attractors is studied. An expansion in powers of the mean-square noise strength is derived for the moments of the conditional probability distribution of position. The results are compared to numerical simulations of the logistic and H\'enon maps, and agree to within the numerical uncertainty.
Diurnal variations on a plasmaspheric flux tube: Light ion flows and F region temperature enhancements

Diurnal variations on a plasmaspheric flux tube were modelled using a time-dependent, multi-species, one-stream, interhemispheric model for plasmaspheric flows. In the model the coupled time-dependent hydrodynamic equations (continuity, momentum, and energy) of a two ion (H+ and O+) quasineutral, currentless plasma are solved for a closed geomagnetic field line; no diffusive equilibrium assumptions are made. For this work an L=2 field line with conjugate points displaced in latitude and longitude was used in order to model the tilt of the geomagnetic field. The simulation was done for June solstice conditions during solar minimum. In general the results reproduce those found by Richards and Torr [1986]. However, a striking new result is the presence of large downward H+ velocities (∼2.2 km/s) at about 320 km altitude in the winter (southern) hemisphere, in early morning when the summer hemisphere is already sunlit but the winter hemisphere is still in darkness. These are accompanied by large H+ temperature enhancements, reaching 5600 K, at about 280 km altitude. The large velocities are a resilt of an increase in the H+ pressure gradient coupled with a decrease in the friction encountered by the H+ ions. These flows are stopped at lower altitudes where the neutral densities are higher; the bulk kinetic energy is converted to thermal energy, resulting in the temperature enhancements.
Stress intensity factors for interacting cracks

Abstract Experimental stress intensity factors (SIFs) for two interacting straight cracks in plane-homogeneous regions were determined. Photoelastic data were collected from digitally sharpened isochromatic fringe patterns by using a digital image analysis system. SIFs were extracted by using the field equations derived from Williams' stress function. Numerical SIFs were also obtained by the boundary integral equation method. Good agreement was observed between experimental and numerical results.
Extracurricular activities and teens' alcohol use: The role of religious and secular sponsorship

Much research has found that more religious youth are less likely to engage in riskier health-related behaviors. However, very little research has examined the role that religion may play in shaping the health-related behaviors of secular youth. There is reason to think that more and less religious youth may gain some health-related benefits from involvement with religious organizations through activities such as basketball and volunteering. Using two waves of data from the National Study of Youth and Religion, this study finds that involvement in religion-supported secular activities is associated with less alcohol use for all involved teens. The number of friends who belong to a religious youth group, in part, explains the relationship. Conversely, network overlap between parents and teens, the number of friends who drink or use drugs, and having an adult confidant from a religious group are not mechanisms that mediate the relationship.
Estimating wrongful convictions

Although numerous cases of wrongful convictions have been documented in the literature and in the media, criminologists have yet to devise a methodology for estimating the extent of such errors in ...
Determinism, Social Science, and Public Administration: Lessons from Isaiah Berlin

This article critically examines the argument that mainstream social science research should play a greater role in public administration inquiry than it has. Drawing in significant part on the ide...
The pith and marrow of our attribute: dialogue of skin and skull in Hamlet and Holbein's The Ambassadors

The heuristics of difference have proved enormously valuable to early modern critical studies, bringing the lives of women, subalterns, as well as national, ethnic, and racial minorities and others...
Haemonchus contortus intestine: a prominent source of mucosal antigens

We sought to identify antigens from Haemonchus contortus, an abomasal nematode of small ruminants, that stimulate local (abomasal lymph node, ALN) CD4+ T lymphocyte responses during a primary infection. Results led to a focus on antigens from the parasite intestine. The H. contortus intestine proved to be a major source of antigens that stimulated ALN CD4+, CD25+ T lymphocyte responses during infections in lambs. When stimulated by intestinal antigens, ALN lymphocytes from these lambs expressed IL-4 and IL-13 transcripts, and, more variably, IFN-gamma. An immunoaffinity-purified fraction, enriched for H. contortus apical intestinal membrane proteins, stimulated similar ALN responses. On further fractionation, antigens from six size classes (ranging from 30 to 200 kDa) also stimulated proliferation of ALN lymphocytes. Mass spectrometry analysis of these size classes identified several known apical intestinal membrane proteins from H. contortus. The results show that H. contortus intestinal antigens warrant investigation in strategies to induce mucosal immunity against this parasite. The specific proteins identified have value for this purpose. The results are in contrast with the now generalized idea that H. contortus intestinal antigens are 'hidden' from the host immune system, and this issue is discussed. The approach also has potential application to other gastrointestinal nematode parasites.
Routine probiotics for premature infants: let's be careful!

Recent technological advances have provided us with the knowledge that when one evaluates the number of genes or cells in the average human, only 10% are mammalian and the rest are microbial.(1, 2) The recent development of non-culture-based-techniques to evaluate microbial DNA is providing new insights into the relationship that exists between microbes and their mammalian hosts, especially the microbes that reside in the gastrointestinal tract(2). Manipulation of the microbial environment of the gastrointestinal tract using probiotics has been considered a means to promote health and prevent disease. Probiotics, according to Food and Agriculture Organization/World Health Organization (FAO/WHO) definition, are: “Live microorganisms which when administered in adequate amounts confer a health benefit on the host.” Probiotics are commonly found in certain fermented foods or supplements with specially added active live cultures, such as in yogurt and dietary supplements. Specific health effects attributed to probiotics that are currently being investigated include alleviation of diarrheal illness, constipation, urogenital infections, atopic diseases, and neonatal necrotizing enterocolitis (NEC).(3)
Concentric and eccentric force–velocity relationships during electrically induced submaximal contractions

The purpose of this investigation was to examine the force-velocity relationship during electrically induced, submaximal concentric and eccentric contractions of the quadriceps femoris muscle. Thirty female subjects with no history of knee pathology participated in the study. Force was measured on an isokinetic dynamometer and the quadriceps femoris muscle was electrically stimulated by use of a medium frequency current generator. Subjects were stimulated at 30% of their maximum voluntary isometric force. Four velocities were tested (30 degrees, 90 degrees, 120 degrees and 180 degrees/sec) during both concentric and eccentric contractions. The relationship between force and velocity was examined with an analysis of covariance. The regression model describing the force-velocity relationship for concentric contractions was significant (p < 0.0001) with an R2 of 0.96 and a slope of -0.76 (p < 0.0001). The regression model describing the force-velocity relationship for eccentric contractions was significant (p < 0.0001) with an R2 of 0.91 and a slope of 0.4 (p < 0.0001). The relationship between force and velocity during electrically induced, submaximal concentric and eccentric contractions were similar to in vitro studies that have examined this relationship during shortening and lengthening contractions.
Exact solutions in the scalar diffraction theory of aberrations

A simple exact method is presented for evaluating the circularly symmetric Fresnel-Kirchhoff diffraction integral in the presence of Seidel aberrations, all orders of spherical aberration, and all orders of linear coma. The resultant formulas involve a simple quadrature over a single special function of mathematics.
The conformation of lipid-free human apolipoprotein A-I in solution.

Apolipoprotein AI (apoA-I) is the principal acceptor of lipids from ATP-binding cassette transporter A1, a process that yields nascent high density lipoproteins. Analysis of lipidated apoA-I conformation yields a belt or twisted belt in which two strands of apoA-I lie antiparallel to one another. In contrast, biophysical studies have suggested that a part of lipid-free apoA-I was arranged in a four-helix bundle. To understand how lipid-free apoA-I opens from a bundle to a belt while accepting lipid it was necessary to have a more refined model for the conformation of lipid-free apoA-I. This study reports the conformation of lipid-free human apoA-I using lysine-to-lysine chemical cross-linking in conjunction with disulfide cross-linking achieved using selective cysteine mutations. After proteolysis, cross-linked peptides were verified by sequencing using tandem mass spectrometry. The resulting structure is compact with roughly four helical regions, amino acids 44–186, bundled together. C- and N-terminal en...
Interactions between femoral venous afferents and lumbar spinal reflex pathways.

Abstract This study reports findings of spinal reflex connections of afferent fibers electrically excited in the wall of the femoral vein. Condition-test experiments, and EMG recordings revealed that the femoral venous afferents have facilitatory connections to flexor and extensor motoneurons of both the proximal and the distal hindlimb muscles. Femoral venous afferent stimulation which produced facilitation, also produced inhibition of the test reflexes following the facilitation. Because the inhibition was enhanced by diazepam injection and because the inhibitory time-course correlated closely to the time-courses of both dorsal root potentials and individual tests of primary afferent depolarization, the inhibition was suggested to be produced by presynaptic inhibition. The potentially significant role of the venous afferent connections in a reflexelicited skeletal muscle pump or in an increase in intramuscular venous counterpressure is discussed.
Image-Based Modeling of Complex Boundaries for CFD Simulation

One outstanding challenge to understanding the behaviors of organisms and organ systems found in nature using CFD simulations lies in modeling the complex geometries and motions they generally exhibit. A route to overcoming this difficulty lies in employing imagery as a basis from which to begin creating such models. To this end we have developed a framework based on image segmentation techniques, followed by a level set based immersed boundary method that operates on a fixed Cartesian mesh. Level set motion is imposed using image morphing techniques, with optical flow used to set boundary conditions. With this approach, still images or movie files obtained from various imaging modalities can be automatically segmented so that flow solutions can be directly connected to image-derived geometries and boundary evolutions. The 2-dimensional methodology applied to a video sequence of an American eel swimming in a water tunnel apparatus is demonstrated presently, with current efforts to extend to 3-dimensions discussed briefly.
Shaped Time-Optimal Feedback Controllers for Flexible Structures

This paper describes the design of closed-loop control laws for servomechanisms with one dominant flexible mode. An input shaping technique is employed to alter the rigid body phase-plane trajectory that is used in time-optimal servomechanisms. The resulting controllers lead to near time-optimal performance without unwanted residual vibrations. After the basic technique is outlined for a system with one undamped flexible mode, extensions are given considering different acceleration and deceleration capabilities, damping, and slew rate limits.
The culturing of dissociated newt forelimb regenerate cells

A procedure is described for the mechanical dissociation and culturing of early stage newt regenerate blastema cells. The specified growth medium is adjusted to suitable osmolarity and consists of Leibovitz L-15, water, fetal calf serum, and insulin. This provides a suitable environment in which growth, proliferation, and some differentiation occur with time as evidenced by phase contrast photographs of living cultures.
Singular nonlinear equations on an unbounded interval

Abstract Variational methods and the critical point theory of Lusternik and Schnirelman are used to prove two abstract theorems. These theorems are utilized to obtain the existence of multiple solutions for a class of nonlinear, singular second order equations on (0, ∞).
Ventricular response to a pressure load. Left ventricular function curves in intact animal.

The response of the left ventricle of the anesthetized dog to graded proximal aortic obstruction was expressed as a ventricular "pressure-function" curve relating peak ventricular pressure to end-diastolic ventricular pressure. Indices were suggested for numerical representation of the pressure-function curve and the normal variations of such indices in the same animal were defined. Pressure-function curves were found to be reproducible in the same animal during changes of cardiac output induced by arteriovenous fistulae or hemorrhage, but not after prolonged ventricular distention by high pressure loads. Changes of the pressure-function curves in both open-chest and closed-chest dogs paralleled changes of ventricular contractility which were expected during anoxia or the action of metaraminol, and which were measured in some experiments by strain-gauge arch or "flow-function" (Starling) curves. A theoretical basis for this relation of the pressure-function curve to ventricular contractility was discussed.
Plastic strain analysis of the machined surface region using fine grid etched by photoresist technique

The photoresist technique was used to generate a mesh of fine grid pattern to determine the plastic strain distribution in the subsurface of machined workpieces. For this purpose rectangular grids measuring 20 μm by 20 μm with a line thickness of 5 μm were etched on workpieces of inconel-718 nickel-base superalloy and then machined under plane-strain condition. Subsurface plastic strain distribution was determined from distorted grids after machining using standard analytical methods. Using this technique, it was possible to generate a finer rectangular grid size of 5 μm by 5 μm with a 2-μm line thickness.
A new separator design for aberration corrected photoemission electron microscopes

Aberration correction of photoemission electron microscopes (PEEM) by electron mirrors requires use of a magnetic beam separator. Due to the stringent requirement on aberrations, such a device is a complex integrated magnetic system. The one that has been installed at BESSY II is essentially fixed in its optical properties hence very susceptible to problems caused by mechanical or magnetic imperfections. Here we present a separate function design that is simple to construct and fully adjustable, which allows more relaxed tolerances on alignment errors and power supply ripples. The simulation with realistic lenses shows that this design gives as good, if not better, a performance as the existing design.
Experimental determination of forces transmitted through the patello-femoral joint

Abstract Tensions in the quadriceps tendon and infrapatellar ligament were measured as a function of flexion angle in eight cadaver knees using a load cell of a materials tester to determine the quadriceps force and a spring balance to quantify the patellar tendon force. The ratio between the tensions in the quadriceps tendon and the patellar tendon ( F Q F P ) ranged from 1.55 at 70° of flexion to 0.86 at 10° of flexion. The patello-femoral joint reaction (PFJR) force for extension against resistance was maximal at 60°. No change in the quadriceps force required to extend the knee occurred with changes of the Q-angle of ±5°. This study demonstrates that FQ does not equal FP as several authors have reported (Bandi, 1972; Barry, 1979; Ficat and Hungerford, 1977; Hungerford and Barry, 1979; Reilly and Martens, 1972; Smidt, 1973). Furthermore, the difference in FQ and FP influences both the magnitude and direction of PFJR. Studies that assess the influence of surgical procedures which alter the patello-femoral joint or the extensor mechanism must take these differences into account.
Succinate dehydrogenase activity and soma size relationships among cat dorsal root ganglion neurons

A large range in succinate dehydrogenase (SDH) activity and soma size among neurons in the dorsal root ganglion (DRG) and the dorsolateral region of the ventral horn (DLVH) at spinal cord level L7 was observed. Mean soma sizes were similar for the two populations. DLVH, but not DRG, neurons showed an inverse relationship between SDH activity and soma size. DRG neurons had a higher mean SDH activity than DLVH neurons, reflecting the observation that there was a population of DRG neurons with a higher oxidative capacity than DLVH neurons.
New Species of Docalidia from the Neotropical Region (Homoptera: Cicadellidae: Coelidiinae)

Fifteen new species of Docalidia are described and illustrated. These are bracchia, temeratis, spira, and morosa from Ecuador, simplex from Ecuador and Peru, ampla, nitida, paraserra, tenuatis, steveni, dextra, oblonga, paradiscissa, adami from Peru and matthewi from Venezuela. Docalidia zanoli Nielson is a lapsus calami and is emended as follows: Docalidia zanolae Nielson.
Pressure Toward Distortion and Involvement in Studying a Civil Rights Organization

The problem of self-management in the field work situation is one of the most frequently recurring themes in social science literature. The researcher's need to structure relationships with his subjects has been repeatedly documented. The idea that data collection can be optimized by paying attention to the distorting consequences of researcher-subject interaction is usually based upon two assumptions: First, that it is in fact possible for the field worker to distinguish his values from those of his subjects; and secondly, that he commands psychological and material resources sufficient to control the interaction between himself and his subjects. This paper discusses a number of problems which emerged in the study of a local civil rights organization and elaborates some of the conditions under which these assumptions have had only limited validity. It attempts to show the kinds of constraints which are imposed upon the research interaction process by the high coincidence of researcher and subject values,...
Effect of recycle on properties and profits: Algorithms

In many plastics processes, nonvirgin materials make up relatively small percentages of materials added to the main processing stream. In thermoforming, however, as much as half the material that passes through the extrusion and thermoforming process chain is “nonproduct” web. Economics usually dictate that this material must be reprocessed. Materials that experience high levels of shear and/or temperature usually exhibit measurable and significant property loss. This means that the mixture of materials fed to the process has properties some-what less than those of the virgin resin. This paper presents algorithms for determining final product properties, given single-pass property loss and fraction of recycle in the resin mixture going to the process. The following cases are considered: Linear, where the single-pass property loss is directly proportional to the mixture property prior to processing. This was first worked out by Smoluk for tensile strengths Power-law, where the single-pass property loss is proportional to the mixture property to a power. Impact strength is an example Offset, where the single-pass property is equal to the mixture property minus a fixed amount. Fire retardancy seems to be an example of this Logarithmic, where the law of mixtures is logarithmic. Viscosity and intrinsic viscosity (molecular weight) are examples here For cases 1, 2, and 4, the algorithm yields a closed solution for steady-state processes. The offset case yields a nested series that converges in about 20 steps. In addition, if a value can be placed on material property loss (either through higher product reject rates or higher virgin material costs), a “profit” algorithm can be created to determine the actual processing costs. From this, scenarios for reuse of regrind and/or off-spec materials can be created. An example of such an algorithm is given.
Placental Passage and Fetal Secretion of Aldosterone

The transplacental passage and production of aldosterone by the mother and fetus were studied near term during a constant infusion of 1,2-3H-aldosterone to 9 mothers at the time of elective cesarean section. This study showed that there was a transplacental passage of aldosterone. The fetal plasma levels of 1,2-3H-aldosterone, expressed as percentage of the matternal values, ranged from 40.0 to 79.2%. The levels of non-labeled hormone, determined by a double isotope dilution technique, were consistently higher in the fetus than in the mother (mean±SD = 17.2±9.5 mμg/100 ml and 3.7±1.4 mμg/100 ml, respectively). Since the specific activities of aldosterone were lower in the fetus than in the mother (6.5 to 23.4%), and if one assumes that equilibrium between maternal and fetal compartments was reached after more than 2 h of constant infusion, it can be concluded that the fetus secretes aldosterone. The metabolic clearance: ate of aldosterone was not modified by pregnancy. The steroid blood production of the mothers was about twice the non-pregnant values. the relatively small increments might be related to the fact that our subjects were supine for at least 10 h at the time of the study.
Analysis of a complete homeobox gene repertoire: Implications for the evolution of diversity

The completion of sequencing projects for various organisms has already advanced our insight into the evolution of entire genomes and the role of gene duplications. One multigene family that has served as a paradigm for the study of gene duplications and molecular evolution is the family of homeodomain-encoding genes. I present here an analysis of the homeodomain repertoire of an entire genome, that of the nematode Caenorhabditis elegans, in relation to our current knowledge of these genes in plants, arthropods, and mammals. A methodological framework is developed that proposes approaches for the analysis of homeodomain repertoires and multigene families in general.
Leukoaraiosis and stroke outcome

We studied the influence of leukoaraiosis on the prognosis of stroke for the first year after onset. Three hundred and seventy consecutive stroke subjects were observed for 1 year. Data were collected prospectively in a questionnaire constructed in accordance with the Stroke Data Bank and analyzed using SPSS. Leukoaraiosis was observed in 17.6% of subjects. Subjects with leukoaraiosis were older than subjects without leukoaraiosis. Cerebrovascular risk factors were similar in both groups. During the first 30 days, the fatality rate of both groups was similar. However, at 1 year, the fatality rate in subjects with leukoaraiosis was higher. Stroke Severity, Weakness Score, and the Barthel Modified Activities for Daily Living score did not differ between groups at 30 days or 1 year. At both 30 days and 1 year, the MMSE score was lower in subjects with leukoaraiosis. Leukoaraiosis did not predict stroke recurrence within 1 year. Leukoaraiosis in stroke patients is an adverse predictor of cognitive functioning at 30 days and at 1 year and is an adverse predictor of survival at 1 year.
The response of human early and late rosette-forming lymphocytes to mixed and autologous lymphocyte culture and mitogens.

Abstract Human peripheral blood lymphocytes were fractionated into “early” and “late” SRBC rosette-forming cells (RFC) by gradient centrifugation of the rosette suspensions. These RFC are putatively regarded as subsets of thymus-derived (T) lymphocytes. The two groups of cells were then cultured in mixed and autologous lymphocyte culture and with 5.0, 1.0, and 0.01 mg/ml of phytohemagglutinin (PHA) and 250, 50, and 10 μg/ml of concanavalin A (Con A). Tritiated thymidine incorporation in these cultures was compared. “Late” RFC were less responsive in mixed and autologous lymphocyte culture as compared to the “early” RFC. The optimum mitogen response of the “early” fraction to PHA occurred at 1.0 mg/ml, while that of the “late” fraction was at 0.01 mg/ml. Similarly, the “late” fraction showed a greater response to the lowest concentration of Con A. It was concluded that the “early” and “late” fractions differed in their response to these stimulants. Experiments were also carried out to ensure that these differences were not due to an artifact of the rosetting technique.
On the time allometry of co-ordinated rhythmic movements.

The focus is the power formulae relating periodic time in terrestrial locomotion and flight to mass and length. The periodic timing of limbs and wings oscillating comfortably in absolute co-ordination is viewed as the characteristic period τ 0 of a system in which the free, undamped oscillatory motion of a point mass m at a distance l from a fixed axis does work against two conservative forces. These forces are in the form of gravity g acting on the point mass and a spring of stiffness k acting at a distance b from the axis. The system's characteristic period can be expressed most simply as: τ 0 = 2 π [ ml 2 /( mlg + kb 2 )] 1/2 . In the biological instantiation of this hybrid mass-spring/simple pendulum system, muscular and other tissues function as the spring that elastically stores and releases mechanical energy. Regular oscillations are brought about and sustained by a muscular driving force that ordinarily is close to resonance. The resultant dynamical regime—basically, raising and lowering a mass at regular intervals with respect to gravity—is referred to as the pendular clocking mode of movement organization. The mode is investigated in the laboratory by having a person swing pendulums in the left and right hands comfortably at a common period and a fixed phase. In absolute co-ordination, two wrist-pendulum systems can be interpreted physically as a virtual single system. The evidence suggests that the scalings of the periodic times of such systems to mass and to length follow directly from the dynamical properties inherent in the resonance equation of the pendular clocking mode. Recourse to biological constants to rationalie the time scale is unnecessary. Experiments on human wrist-pendular activity and detailed analyses of the mass and length dependencies of the locomotory cycle times of quadrupeds, large birds, small passerines, hummingbirds, and insects are performed with respect to the dynamical properties predicted for systems in the pendular clocking mode. The major conclusion is that all the time scales of terrestrial and aerial locomation are the consequences of a single dynamical regime. Differences in locomotory time allometries follow systematically from differences in the length scale and differences in the relation of mass to length.