cssi/SciSciGPT-SciSciNet huggingface dataset:
A Non‐parametric Examination of Capital–Skill Complementarity*

This paper uses non‐parametric kernel methods to construct observation‐specific elasticities of substitution for a balanced panel of 73 developed and developing countries to examine the capital–skill complementarity hypothesis. The exercise shows some support for capital–skill complementarity, but the strength of the evidence depends upon the definition of skilled labour and the elasticity of substitution measure being used. The added flexibility of the non‐parametric procedure is also capable of uncover ing that the elasticities of substitution vary across countries, groups of countries and time periods.
Properties of the strongly correlated two-dimensional electron gas in Si MOSFET's

We discuss properties of strongly correlated two-dimensional electron gas in semiconductor layers at low electron concentrations assuming that the electron liquid is close to crystalization. Analogy with the theory of 3He is emphasized.
2D-ELDOR using full S(c-) fitting and absorption lineshapes.

Recent progress in developing 2D-ELDOR (2D electron-electron double resonance) techniques to better capture molecular dynamics in complex fluids, particularly in model and biological membranes, is reported. The new ''full Scmethod'', which corrects the spectral analysis for the phase distortion effects present in the experiments, is demonstrated to enhance the sensitivity of 2D-ELDOR in reporting on molecular dynamics in complex membrane environments. That is, instead of performing spectral fitting in the magnitude mode, our new method enables simultaneous fitting of both the real and imaginary components of the Scsignal. The full Scfitting not only cor- rects the phase distortions in the experimental data but also more accurately determines instrumental dead times. The phase corrections applied to the Scspectrum enable the extraction of the pure absorption-mode spectrum, which is characterized by much better reso- lution than the magnitude-mode spectrum. In the absorption mode, the variation of homogeneous broadening, which reports on the dynamics of the spin probe, can even be observed by visual inspection. This new method is illustrated with results from model mem- branes of dipalmitoyl-sn-glycero-phosphatidylcholine (DPPC)-cholesterol binary mixtures, as well as with results from plasma mem- brane vesicles of mast cells. In addition to the dynamic parameters, which provide quantitative descriptions for membranes at the molecular level, the high-resolution absorption spectra themselves may be used as a ''fingerprint'' to characterize membrane phases and distinguish coexisting components in biomembranes. Thus we find that 2D-ELDOR is greatly improved with the new ''full Sc� method'' especially for exploring the complexity of model and biological membranes. � 2007 Published by Elsevier Inc.
Sialidase of Rat Liver and Kidney

Abstract Sialidase is shown to be localized in the lysosomes of rat liver and kidney. The pH optimum with sialyllactose as substrate is 4.4, and with glycoproteins is 4.0. The enzyme is not affected by many divalent metal ions, ethylenediaminetetraacetate, or p-chloromercuribenzoate, and is active against many glycoproteins and gangliosides, indicating its possible role in their intracellular digestion.
A New Look at Generalized Rewriting in Type Theory

Rewriting is an essential tool for computer-based reasoning, both automated and assisted. This is because rewriting is a general notion that permits modeling a wide range of problems and provides a means to effectively solve them. In a proof assistant, rewriting can be used to replace terms in arbitrary contexts, generalizing the usual equational reasoning to reasoning modulo arbitrary relations. This can be done provided the necessary proofs that functions appearing in goals are congruent with respect to specific relations. We present a new implementation of generalized rewriting in the Coq proof assistant, making essential use of the expressive power of dependent types and the recently implemented type class mechanism. The new rewrite tactic improves on and generalizes previous versions by natively supporting higher-order functions, polymorphism and subrelations. The type class system inspired by Haskell provides a perfect interface between the user and the tactic, making it easily extensible.
SEROLOGICAL ANALYSES OF CELLULAR SLIME MOLD DEVELOPMENT. II. PREFERENTIAL LOSS, DURING MORPHOGENESIS, OF ANTIGENIC ACTIVITY ASSOCIATED WITH THE VEGETATIVE MYXAMOEBAE.

Sonneborn, D. R. (Brandeis University, Waltham, Mass.), L. Levine, and M. Sussman. Serological analyses of cellular slime mold development. II. Preferential loss, during morphogenesis, of antigenic activity associated with the vegetative myxamoebae. J. Bacteriol. 89:1092–1096. 1965.—A major antigenic component of Dictyostelium discoideum (vegetative myxamoebae) is retained during morphogenesis up to the final stages of fruiting-body construction. It is found in the cells constituting the stalk of the mature fruit but is undetectable in the spores. The nature of the preferential loss of antigen from this cell contingent is unknown. Antiserum prepared against the vegetative myxamoebae is cytotoxic and reduces cell viability by several orders of magnitude at dilutions of about 1:100.
New amorphous thin-film lithium electrolyte and rechargeable microbattery

Sputtering of Li/sub 3/PO/sub 4/ in pure N/sub 2/ results in the formation of an amorphous lithium electrolyte that is suitable in contact with lithium and has electrical properties that are suitable for application in a thin-film cell. Thin-film rechargeable lithium cells have been fabricated and characterized using this electrolyte between a lithium anode and an amorphous vanadium oxide cathode. The open circuit voltage of the cell is 3.6 to 3.7 V, and it has a capacity of 130 mu Ah/cm/sup 2/ when discharged to 1.5 V. The AC impedance of the cells measured at different stages of discharge indicate a significant decrease in internal resistance at about the midpoint of the discharge. >
Bottom-current speed in the Vema Channel recorded by particle size of sediment fine-fraction

Abstract The particle-size distribution of the carbonate-free silt fraction was determined in forty-two core-top samples from the east flank of the Vema Channel in order to allow comparison of the mean particle size with near-bottom current speed based on nearby CTD and current-meter observations. The silt mean particle size fluctuates insignificantly between 1450–3950 m but coarsens markedly below 4000 m under Antarctic-source bottom currents. The top of the zone of coarse sizes approximates the top of Lower Circumpolar Water (LCPW) at ∼4000 m; the steep gradient to coarsest sizes in the axis of the channel marks the transition to Antarctic Bottom Water (AABW). The vertical profile of mean particle size on the east flank correlates in general respects with the vertical velocity gradient in the channel axis although the core sites on the east flank are as far as ∼200 miles from the current-meter arrays. Nevertheless, this relationship is used to infer that the non-carbonate particle sizes deposited on the east flank of the channel may be an indication of bottom-current speed and, therefore, the mean size is used to reconstruct profiles of mean current speed for three time slices (18, 120 and 140 ka B.P.). During glacial isotopic stages 2 and 6 the particle sizes deposited on the east flank of the channel are characterized by finer sizes at nearly all depths and the zone of coarse sizes corresponding to LCPW and AABW deepens. During interglacial isotopic stage 5e, the particlesize profile is very similar to the modern profile; however, LCPW and AABW appear to be deeper than at present. The finer particle sizes deposited at nearly all depths during glacial periods indicates that the velocity of deep circulation in the Atlantic was reduced in response to the ice ages. Deep circulation during isotopic stage 5e closely resembled modern circulation; however, AABW production rates may have been less that at present.
ON THE CLASSIFICATION OF THE CARIDEA (DECAPODA)

Es wird eine vorlaufige Einteilung der Caridea vorgeschlagen, hauptsachlich nach Merkmalen der drei vorderen Paare von Pereopoden und der sechs Paare von Mundteilen, wobei nicht von der Methode kladistischer Merkmalsphylogenie profitiert wird.
The influence of monoamine oxidase inhibition on catecholamine synthesis

Abstract Nagatsu et al. (1) found that a number of catecholamines prevented the conversion of tyrosine to DOPA by the enzyme tyrosine hydroxylase. This finding suggested that catecholamines could influence their own synthesis by inhibiting this rate-limiting enzymatic event. Levitt et al. (2) using the isolated perfused guinea pig heart failed to find evidence for a negative feedback mechanism for the control of catecholamine synthesis. Recent changes in the concept of catecholamine storage (3) and the development of new techniques for calculating amine synthesis rates (4) (5) have enabled us to estimate the synthesis of the amines in tissues when stores are elevated after inhibition of monoamine oxidase (MAO). Our studies demonstrate that the elevation of brain and heart-catecholamine levels is accompanied by a substantial reduction of the synthesis of these amines; this may be the result of inhibition of tyrosine hydroxylase by the increased concentrations of catecholamines.
Associations of neighborhood and family factors with trajectories of physical and social aggression during adolescence.

Adolescents develop within multiple contexts that synergistically influence their behavior and health. To understand the simultaneous influence of neighborhood and family contexts on adolescents, this study examined relationships of neighborhood socioeconomic disadvantage, neighborhood social disorganization, family conflict, parent–child bonding and parental control with trajectories of physical and social aggression. The sample included 5,118 adolescents between ages 11 and 18 (50 % female, 52 % Caucasian) living in predominantly rural areas. Multilevel growth curve models showed an interaction between neighborhood disadvantage, family conflict and gender on the physical aggression trajectories. The interaction suggested more rapid processes of both increase in and desistance from physical aggression over time for boys with high neighborhood disadvantage and high family conflict, as well as a higher starting point, more gradual increase and slower process of desistance over time for girls in similar neighborhood and family contexts. Less parent–child bonding and less parental control also were associated with higher initial levels of physical aggression. For social aggression, an interaction between family conflict and gender showed girls with high family conflict had the highest initial levels of social aggression, with a more gradual increase over time for these girls compared to their male counterparts in high-conflict families or their female counterparts in low-conflict families. Less parent–child bonding was associated with higher initial levels and a faster increase over time of social aggression, and less parental control was associated with higher initial levels of social aggression. The findings suggest early family-based interventions may help prevent perpetration of both physical and social aggression during adolescence.
Genetic Planning Method and its Application to Planetary Exploration

This paper describes a genetic algorithm planning method for autonomous robots in unstructured environments. It presents the approach and demonstrates its application to a laboratory planetary exploration problem. The method represents activities of the robot with discrete actions, or action modules. The action modules are assembled into an action plan with a Genetic Algorithm (GA). A successful plan allows the robot to complete the task without violating any physical constraints. Plans are developed that explicitly consider constraints such as power, actuator saturation, wheel slip, and vehicle stability. These are verified using analytical models of the robot and environment. The methodology is described in the context of planetary exploration similar to the NASA Mars Pathfinder mission. More aggressive missions are planned where rovers will explore scientifically important areas that are difficult to reach (e.g., ravines, craters, dry riverbeds, and steep cliffs). The proposed approach is designed for such areas.
NMDA receptor blockade reduces temporomandibular joint-evoked activity of trigeminal subnucleus caudalis neurons in an estrogen-dependent manner

Estrogen status is a risk factor in painful temporomandibular disorders (TMJD). Previously we reported that estradiol (E2) enhanced nociceptive processing of TMJ input by neurons in superficial laminae at the spinomedullary (Vc/C(1-2)) region; however, the mechanisms for this enhancement are not known. The present study determined if ionotropic glutamate receptors contribute to TMJ nociceptive processing in an E2-dependent manner. Ovariectomized (OvX) female rats were treated with high E2 (HE2) or low dose E2 (LE2) for 2 days and neural activity was recorded in laminae I-II at the Vc/C(1-2) region. TMJ-responsive units were activated by ATP injections into the joint space. ATP-evoked unit responses in HE2 rats were reduced significantly by topical application of the N-methyl-D-aspartate receptor antagonist, D(-)-2-amino-5-phosphonopentanoic acid (AP5) in a dose-related manner, while units from LE2 were not affected. Application of the non-NMDA receptor antagonist, 6,7-dinitroquinoxaline-2,3-dione (DNQX), inhibited the ATP-evoked responses in both groups. Spontaneous activity of TMJ units was not influenced by AP5, whereas it was reduced by DNQX similarly in both groups. The high threshold convergent cutaneous receptive field area of TMJ units was not changed by AP5, whereas DNQX caused a significant reduction in both groups. These results suggest that NMDA-dependent mechanisms contribute to the enhanced ATP-evoked responses of TMJ units in superficial laminae at the Vc/C(1-2) region under high E2 conditions, while non-NMDA-dependent mechanisms modify the encoding properties of TMJ units independent of E2 status.
Information Space Receding Horizon Control

In this paper, we present a receding horizon solution to the optimal sensor scheduling problem. The optimal sensor scheduling problem can be posed as a partially observed Markov decision problem whose solution is given by an information space (I-space) dynamic programming (DP) problem. We present a simulation-based stochastic optimization technique that, combined with a receding horizon approach, obviates the need to solve the computationally intractable I-space DP problem. The technique is tested on a sensor scheduling problem, in which a sensor must choose among the measurements of N dynamical systems in a manner that maximizes information regarding the aggregate system over an infinite horizon. While simple, such problems nonetheless lead to very high dimensional DP problems to which the receding horizon approach is well suited.
Micropolar fluids with stretch

Abstract Equations of motion, constitutive equations, and boundary conditions are derived for a class of micropolar fluids which can stretch or contract. These fluids respond to intrinsic rotational motions and spin inertia and therefore can support couple stress and body couples. In addition, microelements of such fluids can stretch or contract so that intrinsic extensional motions are possible. It is conjectured that the model constructed will have applications in liquid crystals, fluids with polymeric additives, and turbulent motions of Newtonian fluids. Thermodynamical restrictions are studied in detail, and field equations are obtained for the density, microinertia, velocity vector, microrotation vector, and the microstretch.
SOURCE OF COLLAGEN AT EPITHELIOMESENCHYMAL INTERFACES DURING INDUCTIVE INTERACTION.

Abstract The data reported indicate that embryonic salivary mesenchyme, initially labeled with tritiated proline or glycine, transmits a labelable material across a filter membrane between the mesenchyme and salivary epithelium. The material accumulates at the epithelial surface with a distribution similar to that of ultrastructurally identifiable collagen. The suggestion that the label actually is in collagen is in conformity with, but not conclusively demonstrated by, the facts that collagen is rich in proline and glycine and the label is removed by collagenase treatment of sections but not by hyaluronidase treatment. On the other hand, embryonic salivary epithelium initially labeled with proline or glycine does not similarly deposit label in a pattern which coincides with the distribution of collagen. The data are interpreted to favor the hypothesis that basement membrane formation involves transfer of soluble tropocollagen from the mesenchyme, where it is synthesized, to the epithelial surface, where it is polymerized.
An analysis of parity-violating pion-nucleon couplings

Abstract We construct to all orders in the pion field and to one power of pion momentum the most general lagrangian for parity-violating pion-nucleon interactions that can arise from weak interactions. In particular, we show that in addition to the previously discussed P-violating πNN vertex, there are independent ππNN, and πγNN interactions. All three may be relevant for nuclear and atomic parity-violation experiments, as well as P-violating elastic nucleon scattering. We give numerical estimates for the interactions, and show that there is reason to believe that the Z°-induced strange-quark operator ( s γ μ γ 5 s)( u γ μ u− d γ μ d) contributes significantly in the ΔI = 1 channel.
Impacts of Columbia River discharge on salmonid habitat: 1. A nonstationary fluvial tide model

[1] This is the first part of a two-part investigation that applies nonstationary time series analysis methods and the St. Venant equations to the problem of understanding juvenile salmonid access to favorable shallow-water habitat in a tidal river. Habitat access is a function of river stage, tidal range, and the distribution of bed elevation. Part 1 models nonstationary tidal properties: species amplitudes and phases and tidal range. Part 2 models low-frequency river stage in the Lower Columbia River and reconstructs historical water levels, using the tidal model from part 1. To incorporate the nonstationary frictional effects of variable river discharge into the tidal model, we decompose the tidal wave into tidal species and calculate daily tidal range. Our one-dimensional tidal model is based on analytic wave solutions to the linearized St. Venant equation and uses six coefficients per tidal species to represent the upstream evolution of the frictionally damped tidal wave. The form of the coefficients is derived from the St. Venant equations, but their values are determined objectively from the data. About 50 station-years of surface elevation data collected (1981–2000) below Bonneville Dam (235 km from the ocean) were processed with a wavelet filter bank to retrieve time series of tidal species properties. A min-max filter was used to estimate daily tidal range. Tidal range, diurnal, and semidiurnal amplitudes were predicted with mean root mean square errors <30 mm, which is significantly more accurate than predictions obtained from harmonic analysis. Thus despite the compact form of our solution, we model nonstationary fluvial tidal properties with a high level of accuracy.
The effect of ethanol and acetaldehyde on [14C]pantothenate incorporation into CoA in cultured rat liver parenchymal cells.

Abstract The effect of ethanol on [ 14 C]pantothenate incorporation into CoA and on total CoA levels was measured in 3-day-old primary cultures of adult rat liver parenchymal cells. Ethanol decreased the incorporation of radioactivity into CoA a maximum of 67%, 5 m m ethanol was saturating for the inhibitory effect and 0.2 m m ethanol was sufficient for half-saturation. This inhibitory effect did not result from a loss of CoA precursors or from cell death. Ethanol concentrations up to 10 m m did not decrease the ATP content of cells or the total protein content of cells which adhered to the incubation flask. Ethanol (5 m m ) had no effect on the cyteine + cystine content of the cells. Intracellular pantothenate concentrations were not affected by 5 m m ethanol, and increasing the pantothenate concentration did not affect ethanol inhibition. Ethanol inhibition of [ 14 C]pantothenate conversion to CoA could be fully reversed by rinsing the cells free of ethanol. The ethanol inhibition could also be fully reversed by addition of 4-methylpyrazole, indicating that ethanol must be oxidized via alcohol dehydrogenase to exert its inhibitory effect. Acetaldehyde, the immediate product of alcohol dehydrogenase, was also an inhibitor of the incorporation of [ 14 C]pantothenate into CoA; the maximum inhibition was 63%. Acetaldehyde concentrations maintained between 18 and 103 μ m inhibited incorporation by 57%. The inhibition by acetaldehyde did not correlate well with changes in the NADH and NAD + ratio of the cells (as determined by measuring changes in the lactate-to-pyruvate ratio). The ability of glucagon, dibutyryl cAMP + theophylline, or dexamethasone to stimulate [ 14 C]pantothenate conversion to CoA was not decreased by the addition of ethanol or acetaldehyde, indicating that ethanol inhibition does not occur by reversal of the cAMP-mediated regulatory mechanism for CoA biosynthesis.
Raman shifting of KrF laser radiation for tropospheric ozone measurements

The differential absorption lidar (DIAL) measurement of tropospheric ozone requires use of high average power UV lasers operating at two appropriate DIAL wavelengths. Laboratory experiments have demonstrated that a KrF excimer laser can be used to generate several wavelengths with good energy conversion efficiencies by stimulated Raman shifting using hydrogen (H2) and deuterium (D2). Computer simulations for an airborne lidar have shown that these laser emissions can be used for the less than 5 percent random error, high resolution measuremment of ozone across the troposphere using the DIAL technique. In the region of strong ozone absorption, laser wavelengths of 277.0 and 291.7 nm were generated using H2 and D2, respectively. In addition, a laser wavelength at 302.0 nm was generated using two cells in series, with the first containing D2 and the second containing H2. The energy conversion efficiency for each wavelength was between 14 and 27 percent.
Experimental measurement of dynamic fluid shear stress on the aortic surface of the aortic valve leaflet.

Aortic valve (AV) calcification is a highly prevalent disease with serious impact on mortality and morbidity. Although exact causes and mechanisms of AV calcification are unclear, previous studies suggest that mechanical forces play a role. Since calcium deposits occur almost exclusively on the aortic surfaces of AV leaflets, it has been hypothesized that adverse patterns of fluid shear stress on the aortic surface of AV leaflets promote calcification. The current study characterizes AV leaflet aortic surface fluid shear stresses using Laser Doppler velocimetry and an in vitro pulsatile flow loop. The valve model used was a native porcine valve mounted on a suturing ring and preserved using 0.15% glutaraldehyde solution. This valve model was inserted in a mounting chamber with sinus geometries, which is made of clear acrylic to provide optical access for measurements. To understand the effects of hemodynamics on fluid shear stress, shear stress was measured across a range of conditions: varying stroke volumes at the same heart rate and varying heart rates at the same stroke volume. Systolic shear stress magnitude was found to be much higher than diastolic shear stress magnitude due to the stronger flow in the sinuses during systole, reaching up to 20 dyn/cm2 at mid-systole. Upon increasing stroke volume, fluid shear stresses increased due to stronger sinus fluid motion. Upon increasing heart rate, fluid shear stresses decreased due to reduced systolic duration that restricted the formation of strong sinus flow. Significant changes in the shear stress waveform were observed at 90 beats/min, most likely due to altered leaflet dynamics at this higher heart rate. Overall, this study represents the most well-resolved shear stress measurements to date across a range of conditions on the aortic side of the AV. The data presented can be used for further investigation to understand AV biological response to shear stresses.
Evaluation of Expanded Polytetrafluoroethylene Arteriovenous Access Grafts onto which Microvessel-Derived Cells were Transplanted to ``Improve'' Graft Performance: Preliminary Results

The purpose of this study was to implement and evaluate a clinical protocol for following longitudinally the luminal responses of microvessel cell seeded expanded polytetrafluoroethylene (ePTFE) vascular grafts implanted for hemodialysis access. Half of the patients enrolled in the study were randomized to receive grafts that were “seeded” with transplanted microvessel cells derived from autologous subcutaneous fat; the other half of the patients received nonseeded grafts. The patients agreed to scheduled biopsies of their grafts at three postoperative times. All biopsy samples were evaluated by routine histologic and electron microscopy techniques. Three men and six women were enrolled in the study. All operative procedures were tolerated well. However, only two of the nine patients agreed to 1-year postimplantation biopsies; one of these patients had been randomized to receive a “nonseeded” ePTFE graft and one randomized to receive a “seeded” graft. The “seeded” graft at 3 months showed endothelial cells on the luminal surface as well as some intimal thickening. By 20 months, the same “seeded” graft showed significant concentric intimal thickening and by 24 months, this “seeded” graft thrombosed. The “nonseeded” graft at 16 months had irregular areas of intimal thickening which were quite patchy in nature. The flow contacting surface of the “nonseeded” graft remained thin. The intima of the “seeded” graft was twice as thick as that of the “nonseeded” graft. The methodologies implemented in the study design were appropriate. Biopsy samples were obtained without complication and were easily processed for analysis. Patient compliance with the biopsy protocol was problematic however. The study was terminated because of the development of significant concentric intimal hyperplasia in a “seeded” graft. (Ann Vasc Surg 1998;12:405–411.)
Convergence analysis of FxLMS-based active noise control for repetitive impulses

This paper presents the performance of applying the filtered-x least mean squares (FxLMS) algorithm to attenuate repetitive impact acoustic noise. The FxLMS algorithm has been widely adopted in active noise control (ANC) system for various relatively stationary disturbances. However, its convergence behavior for transient impulse has not received as much attention. Directly applying this algorithm to individual transient event exhibit difficulties since it requires certain adaptation time to converge satisfactorily. But for transient noise with certain repeatability, the FxLMS algorithm may be capable of learning. A theoretical convergence analysis of the FxLMS algorithm for repetitive impact noise is conducted. To simplify the derivation, the secondary path is assumed to be a pure delay model. Through this analysis, a step size bound condition is derived, and an optimal step size that leads to the fastest convergence rate is determined. Then, numerical simulations are performed considering various pure delay secondary path models to validate the theoretical analysis. Furthermore, a laboratory test is developed to demonstrate the capability of FxLMS algorithm for active control of repetitive impact noise. The analysis shows promising results of applying active noise control system with the FxLMS algorithm to repetitive transient noise typically seen in industrial facilities.
Commuting Smoothed Projectors in Weighted Norms with an Application to Axisymmetric Maxwell Equations

We construct finite element projectors that can be applied to functions with low regularity. These projectors are continuous in a weighted norm arising naturally when modeling devices with axial symmetry. They have important commuting diagram properties needed for finite element analysis. As an application, we use the projectors to prove quasioptimal convergence for the edge finite element approximation of the axisymmetric time-harmonic Maxwell equations on nonsmooth domains. Supplementary numerical investigations on convergence deterioration at high wavenumbers and near Maxwell eigenvalues and are also reported.
The caudal neurosecretory system of fishes.

Abstract The comparative microanatomy, cytology, and ultrastructure of the caudal neurosecretory system of teleost fishes are surveyed, and some of the variations in morphologic features of the urohypophysis are indicated, based on the study of 125 teleost species. The neurohemal organ, the urohypophysis, was present in every teleost specimen studied. The general morphology of the teleost caudal system parallels the cranial (hypothalamo-neurohypophyseal) system in the tetrapods. The ultrastructural characteristics are also strictly comparable; the “Gomori-negative” neurosecretion of the caudal system is composed largely of elementary neurosecretory granules in the 1000 to 3000 A range. These granules appear to be organized in the perikaryon by the Golgi apparatus. No urohypophysis has been found in any nonteleost fish. The caudal neurosecretory neurons are present in elasmobranchs; here the neurochemal area is a diffuse capillary bed on the ventral surface of the spinal cord. Some primitive isospondylous teleosts, as well as some highly specialized forms, have a diffuse and extended urohypophyseal region. The possible evolution of this system is considered. Experimental studies on urohypophysectomized Tilapia mossambica exposed to hypertonic saline, with and without attempted replacement therapy, support an osmoregulatory role for the urohypophysis. Tilapia without their urohypophyses, subjected to a hypertonic environment, showed increased mortality, increased loss of body weight, increased serum chloride levels, and increased prominence of the preoptic nucleus, as compared with sham-operated or intact controls.
Pore space morphology analysis using maximal inscribed spheres

Abstract A new robust algorithm analyzing the geometry and connectivity of the pore space of sedimentary rock is based on fundamental concepts of mathematical morphology. The algorithm distinguishes between the “pore bodies” and “pore throats,” and establishes their respective volumes and connectivity. The proposed algorithm also produces a stick-and-ball diagram of the rock pore space. The tests on a pack of equal spheres, for which the results are verifiable, confirm its stability. The impact of image resolution on the algorithm output is investigated on the images of computer-generated pore space. One of distinctive features of our approach is that no image thinning is applied. Instead, the information about the skeleton is stored through the maximal inscribed balls or spheres (MIS) associated with each voxel. These maximal balls retain information about the entire pore space. Comparison with the results obtained by a thinning procedure preserving some topological properties of the pore space shows that our method produces more realistic estimates of the number and shapes of pore bodies and pore throats, and the pore coordination numbers. The distribution of maximal inscribed spheres makes possible simulation of mercury injection and computation of the corresponding dimensionless capillary pressure curve. It turns out that the calculated capillary pressure curve is a robust descriptor of the pore space geometry and, in particular, can be used to determine the quality of computer-based rock reconstruction.
Political Elites and Constitutional Change

Despite referendums, the process of constitutional reform will be largely determined by parliament. The attitudes of politicians, particularly Labour MPs, are likely to play a critical role here. Therefore this paper addresses the question whether there is now a consensus in parliament, particularly among Labour MPs, in support of the constitutional reform agenda. The conclusion considers the implications of the analysis for patterns of party competition and for prospects of constitutional reform in Brita in.
Pitfalls and related improvements of in vivo gas uptake pharmacokinetic experimental systems.

Gas uptake chamber studies have been widely used to study inhalation pharmacokinetics (PKs) in rodents, often for the ultimate purpose of developing physiologically-based pharmacokinetic (PBPK) models that can be used to describe human PKs and to support risk assessment for the chemical. In the course of our studies of gasoline PKs, we revisited several important issues heretofore not thoroughly addressed. Here, we report several refinements which will significantly improve future studies with this type of system, relating to the understanding of loss rates, the importance of carbon dioxide removal, and sampling of blood and chamber air at the same time. Losses of chemicals in gas uptake systems consist of leakage, adsorption to system components, and adsorption to the hair and skin (fur) of experimental animals. The loss rates were experimentally determined for a series of chemicals and mixtures including n-hexane, benzene, toluene, ethylbenzene, o-xylene, gasoline, and other gasoline components. The rat...
Posttranscriptional silencing of cytochrome P4501A1 (CYP1A1) during zebrafish (Danio rerio) development.

Induction patterns of cytochrome P4501A1 (CYP1A1), an early biochemical marker of exposure to the environmental toxicant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, or dioxin) were investigated during zebrafish (Danio rerio) development. A zebrafish CYP1A1 cDNA fragment was cloned and used to detect CYP1A1 mRNA in embryos exposed to TCDD (1 or 10 nM). Induction of CYP1A1 activity was dependent on age and state of hatch. CYP1A1 mRNA was observed by 15 hr postfertilization. CYP1A1 protein and monooxygenase activity were not detected until 3 days postfertilization and after hatch, as determined by Western immunoblot analysis and ethoxyresorufin O-deethylase (EROD) activity, respectively. In contrast to embryos, concomitant induction of mRNA and activity was detected in juvenile zebrafish (3 days posthatch) after 6 hr of TCDD exposure. Asynchronous induction of CYP1A1 mRNA and activity during development may be a general regulatory mechanism, as similar ontogenetic expression of this gene was demonstrated in mouse embryos. To our knowledge, this is the first report of CYP1A1 posttranscriptional silencing during embryogenesis. Our data suggest that TCDD-mediated induction of CYP1A1 activity is regulated differentially in developing and mature systems. © 2001 Wiley-Liss, Inc.
Efficient Spatial Processing Element Control via Triggered Instructions

In this article, the authors present triggered instructions, a novel control paradigm for arrays of processing elements (PEs) aimed at exploiting spatial parallelism. Triggered instructions completely eliminate the program counter and allow programs to transition concisely between states without explicit branch instructions. They also allow efficient reactivity to inter-PE communication traffic. The approach provides a unified mechanism to avoid overserialized execution, essentially achieving the effect of techniques such as dynamic instruction reordering and multithreading, which each require distinct hardware mechanisms in a traditional sequential architecture.
A Controlled Study to Determine Measurement Conditions Necessary for a Reliable and Valid Operative Performance Assessment: A Controlled Prospective Observational Study

Objective This study evaluated operative performance rating (OPR) characteristics and measurement conditions necessary for reliable and valid operative performance (OP) assessment. Background Operative performance is a signature surgical-practice characteristic that is not measured systematically and specifically during residency training. Methods Expert surgeon raters from multiple institutions, blinded to resident characteristics, independently evaluated 8 open and laparoscopic OP recordings immediately after observation. Results A plurality of raters agreed on operative performance ratings (OPRs) for all performances. Using 10 judges adjusted for rater idiosyncrasies. Interrater agreement was similar for procedure-specific and general items. Higher post graduate year (PGY) residents received higher OPRs. Supervising-surgeon ratings averaged 0.51 points (1.2 standard deviations) above expert ratings for the same performances. Conclusions OPRs have measurement properties (reliability, validity) similar to those of other well-developed performance assessments (Mini-CEX [clinical evaluation exercise], standardized patient examinations) when ratings occur immediately after observation. OPRs by blinded expert judges reflect the level of resident training and are practically significant differences as the average rating for PGY 4 residents corresponded to a "Good" performance whereas those for PGY 5 residents corresponded to a "Very Good" performance. Supervising surgeon ratings are higher than expert judge ratings reflecting the effect of interpersonal factors on supervising surgeon ratings. Use of local and national norms for interpretation of OPRs would adjust for these interpersonal factors. The OPR system provides a practical means for measuring operative performance, which is a signature characteristic of surgical practice.
Aggregatibacter Actinomycetemcomitans Leukotoxin Disrupts Membranes By Inducing the Formation of An Inverted Hexagonal Lipid Phase

The leukotoxin (LtxA) secreted by Aggregatibacter actinomycetemcomitans is a member of the repeats-in-toxin (RTX) family, and like the other members of the family, is a virulence protein which destroys host cells. LtxA exhibits specificity to human white blood cells, thereby allowing A. actinomycetemcomitans to flourish in the human upper aerodigestive track. Scanning electron micrographs of LtxA-treated human immune cell lines showed that LtxA induces the formation of large pores, which appear to be caused by membrane bending. To understand the molecular mechanism of this interaction, we analyzed the behavior of LtxA-membrane interactions in model membranes. Freeze-fracture transmission electron microscopy revealed the presence of unique structures, such as nanotubules, in multilamellar liposomes treated with LtxA. Formation of these structures indicated that the toxin acts by bending the membrane, possibly by inducing a bilayer-to-nonbilayer transition. This phase transition was quantified using differential scanning calorimetry, and it was found that LtxA is a potent inverted hexagonal (HII) phase promoter. The relationship between HII phase induction and membrane disruption was determined with a calcein leakage assay. LtxA-induced leakage from calcein-encapsulating liposomes composed of lipids with negative curvature, favoring HII phase formation, was significantly enhanced compared to leakage from liposomes composed of lipids with neutral curvature, favoring bilayer formation. Addition of lipids with positive curvature, inhibiters of HII phase formation, or cholesterol sulfate, a bilayer stabilizer, completely eliminated calcein leakage. It appears that LtxA causes membrane disruption by inducing the formation of the HII phase, and its toxic effect is therefore highly dependent on lipid curvature. Supported by NIH DE09517.
Electrorheological determination of the Leslie viscosity coefficient (α2) of a main-chain liquid crystal polymer in a nematic solvent

Analysis of the electrorheological response of thermotropic solutions of a main-chain liquid crystal polymer (MCLCP) in a low molar mass nematic solvent is performed at a fixed shear rate as a function of the applied field strength. The Leslie viscosity coefficient α2 can be obtained by least squares fits to an equation describing the balance between the viscous and electric torques, formulated via the two dimensional Leslie-Ericksen-Parodi theory. We find that the increment Δα2 on dissolving the MCLCP increases linearly with molecular weight, consistent with earlier light scattering measurements of the increment in the twist viscosity, Δγ1, and also with previous electrorheological measurements of the increment in the Miesowicz viscosity Δηc.
Evidence of perineural invasion on prostate biopsy specimen and survival after radical prostatectomy.

Objective To better understand relationships between perineural invasion (PNI) and radical prostatectomy outcomes, we examined whether PNI was independently associated with adverse pathologic features and worse survival outcomes after radical prostatectomy. Methods PNI is a routinely reported pathologic parameter for prostate biopsy specimens. We identified 3226 patients undergoing radical prostatectomy for clinically localized prostate cancer at our institution between 1994 and 2010. We used multivariable logistic regression models to examine whether PNI was independently associated with extraprostatic extension, seminal vesicle invasion, and surgical margin status. We used Kaplan-Meier methods and the log-rank test to assess disease-free, prostate cancer-specific, and overall survival according to PNI status. Cox proportional hazards modeling was used to evaluate relationships between PNI and survival outcomes. Results PNI was identified in the prostate biopsy specimen in 20% of patients who underwent radical prostatectomy. Patients with PNI were more likely to have adverse pathologic features, including extraprostatic extension, seminal vesicle invasion, and positive surgical margins. Patients with PNI had shorter disease-free, cancer-specific, and overall survival (all log-rank P Conclusion PNI was independently associated with adverse pathologic features and worse survival outcomes after radical prostatectomy. For these reasons, PNI on prostate biopsy specimens should be considered in prostate cancer treatment decision making and clinical care.
Podcasting as a novel way to communicate with medical school applicants.

Podcasting in medical education is becoming more widely used and may be a useful tool for communicating with applicants to medical school. Given recent trends in the popularity of podcasting and mobile media, we created a podcast to communicate more effectively with applicants to our medical school as well as with the broader premedical community. The purpose of this study was to characterize the listening habits and motivations of our audience and compare the podcast’s benefits to those of other resources. We additionally sought to understand patterns by which our podcast was consumed by a premedical audience. We surveyed medical school applicants who interviewed at the University of Chicago Pritzker School of Medicine for matriculation in 2013. Forty-one percent of those surveyed had listened to the podcast prior to their interview. Only 12 % of listeners accessed the podcast using a mobile device. Ninety-two percent of listeners felt that it faithfully represented the medical school, and 81 % felt that listening would encourage the decision to matriculate. A majority of listeners responded that the podcast was more helpful than other traditional resources. This is the first use of podcasting in medical school admissions and represents a novel way to communicate with prospective students. Our findings demonstrate that podcasting can be an effective tool for communicating with applicants to medical school and highlight its usefulness in recruitment. This method of communication could be adopted by other medical schools to enhance the ways in which they inform their own prospective medical students.
Charmonium in medium: From correlators to experiment

We set up a framework in which in-medium charmonium properties are constrained by thermal lattice quantum chromodynamics and subsequently implemented into a thermal rate equation enabling the comparison with experimental data in heavy-ion collisions. Specifically, we evaluate phenomenological consequences for charmonium production originating from two different scenarios in which either the free or the internal energy are identified with the in-medium two-body potential between charm and anticharm quarks. These two scenarios represent $J/\ensuremath{\psi}$ ``melting temperatures'' of approximately $1.25{T}_{c}$ (``weak binding'') and $2{T}_{c}$ (``strong binding''), respectively. Within current uncertainties in dissociation rates and charm-quark momentum spectra, both scenarios can reproduce the centrality dependence of inclusive $J/\ensuremath{\psi}$ yields in nuclear collisions at the Super Proton Synchrotron (SPS) and the Relativistic Heavy-Ion Collider (RHIC) reasonably well. However, the ``strong-binding'' scenario associated with the internal energy as the potential tends to better reproduce current data on transverse momentum spectra at both SPS and RHIC.
Electron microscopic tomography: A tool for probing the structure and function of subcellular components

Tomography is a powerful tool for obtaining three-dirotation geometry. Although single-axis data collection is stanmensional information from transmission electron microscopy, but its dard in biomedical imaging (e.g., CAT scan, scanning via compuapplication faces unique challenges. A single-axis tilt geometry for terized axial tomography), other data collection geometries are data collection results in anisotropic resolution because full angular also routinely used. coverage is not feasible for most specimen preparations. This effect In the last 10 years, electron tomography has proved to be an can be minimized by combining two single-axis tilt series that have effective tool for 3D structure–function determination in cellular been collected orthogonal to each other. Rapid freezing has been and molecular biology (reviewed in [6–8]) . Recent successful successfully used to preserve the native structure of biological speciapplications include determining the location of microtubule initimens in a form that can be visualized in the high-vacuum environment ation sites in centrosomes isolated from fruit fly embryos [9] , required for electron microscopy; however, these preparations are extremely labile to electron exposure. As a result, application of todemonstrating dynamic changes that occur in muscle Z bands mography to frozen-hydrated specimens has only recently become with contraction [10], characterizing the arrangement and morfeasible with the development of automatic data collection, and with phology of crystals formed during the initial events of bone fora renewed appreciation for the principle of dose fractionation. Even mation [11,12], and providing new insight into the folding of with the limitations of traditional specimen preparations and convenDNA into chromosomes [13,14]. Here we briefly review the tional methods of data collection, electron microscopic tomography methodology, including recent efforts to overcome radiation damhas been successfully employed to probe the structure and function age and an unfavorable specimen geometry, and present a new of several important cellular components. Current efforts include comapplication where electron tomography is combined with videobining electron microscopic tomography and video-enhanced light enhanced light microscopy to correlate structural determination microscopy to correlate ultrastructural variation with the direction of with motion. chromosome motion during mitosis. q 1997 John Wiley & Sons, Inc. Int J Imaging Syst Technol, 8, 175–187, 1997