cssi/SciSciGPT-SciSciNet huggingface dataset:
Practical Planning: Extending the Classical AI Planning Paradigm

1 Reasoning about Actions and Planning 2 Basic Assumptions and Limitations 3 SIPE and Its Representations 4 Hierarchical Planning as Differing Abstraction Levels 5 Constraints 6. The Truth Criterion 7 Deductive Causal Theories 8 Plan Critics 9 Resources: Reusable, Consumable, Temporal 10 Search 11 Replanning During Execution 12 Planning and Reactivity 13 Achieving Heuristic Adequacy 14 Comparison with Other Systems
‘Sideshadowing’ in Virgil’s ‘Aeneid’

Unlike the Homeric epos, which is enclosed in an absolute past, the Aeneid forges a continuity between myth and the historical present and its plot is the fulfillment of a future which is preordained by Fate. As a result, Virgil’s epic has often been regarded as the expression of the immobilization of history rather than its open-endedness. Contrary to the idea of the Aeneid as a mere narrative teleology, the numerous untimely deaths of young heroes and their un-enacted futures bring about elements of temporal condensation that not only add uncertainty to the narrative, but undermine the idea of the present as the only inevitable realization of the past. The sideshadowing created by mors immatura opens loopholes in the poem and stands as a counterpoint to epic as the genre of absolute truths and historical determinism.
Product-limit Estimators and Cox Regression with Missing Censoring Information

The Kaplan–Meier estimator of a survival function requires that the censoring indicator is always observed. A method of survival function estimation is developed when the censoring indicators are missing completely at random (MCAR). The resulting estimator is a smooth functional of the Nelson–Aalen estimators of certain cumulative transition intensities. The asymptotic properties of this estimator are derived. A simulation study shows that the proposed estimator has greater efficiency than competing MCAR-based estimators. The approach is extended to the Cox model setting for the estimation of a conditional survival function given a covariate.
Localization and Dynamics of Phosphatidylinositol 4,5-Bisphosphate (PIP2) in Adult Skeletal Muscle Fibers

PIP2 is a precursor of important second messengers, and by itself is a direct modulator of the activity of ion channels and transporters. We investigated the localization and dynamic changes in PIP2 levels in live adult muscle fibers by expressing two PIP2 sensors: an EGFP construct of the pleckstrin homology (PH) domain of the phospholipase delta1 subunit (PH-EGFP), and a construct of the PIP2 binding domain of the tubby protein (EGFP-tubby). EGFP-tubby has higher affinity and specificity for PIP2 than PH-EGFP, and has been used to sequester PIP2 in the plasma membrane. Their respective plasmids (∗) were transfected by in vivo electroporation of FDB muscles. Two-photon laser scanning microscopy (TPLSM) shows that both EGFP-tubby and PH-EGFP are efficiently expressed in muscle fibers and that they are distributed in a double-banded pattern indicating localization at the transverse tubular system (TTS) membranes (in addition to the sarcolemma). Peak/baseline ratio analysis of TPLSM images suggests that there is a larger proportion of EGFP-tubby than PH-EGFP associated with the TTS membranes. Although the expression of PH-EGFP does not change neither the voltage-dependence nor the amplitude of Ca2+ release signals detected with Rhod-5N, the expression of EGFP-tubby apparently left-shifts their voltage-dependence by >10 mV. To further investigate the localization and dynamics of PIP2 in the TTS, we performed fluorescence resonance energy transfer (FRET) studies. The voltage-dependence of FRET signals, based on the translocation of the lipophilic anion dipicrylamine (DPA), shows that the EGFP tags of both PH-EGFP and EGFP-tubby are anchored within ∼6-9 nm of the TTS membrane. (∗)The plasmids were kindly provided to us by Dr. Tamas Balla, NICHD, NIH. This work was supported by NIH grants AR047664, AR041802, and AR054816.
Regulation of α and Rat Luteinizing Hormone-β Messenger Ribonucleic Acids during Gonadotropin-Releasing Hormone Agonist Treatment in Vivo in the Male Rat*

Agonist analogs of GnRH, after an initial period of stimulation, down-regulate gonadotropin secretion in both man and experimental animals. To study the pretranslational changes in LH subunits during GnRH agonist (GnRH-A) treatment in vivo, 55-day-old male Wistar rats were divided into two groups as follows: 1) sham operated, and 2) testosterone (T)-replaced castrated animals. T replacement was given by 20-mm T implants. Each group was subdivided into two subgroups to receive either saline or 1 microgram GnRH-A (D-Leu6,Des,Gly10-GnRH Net) by daily sc injection. Pituitaries were harvested after 1, 7, and 28 days of GnRH-A treatment for measurements of LH subunit mRNAs by dot hybridization assay. Serum LH concentrations were measured by a RIA. In intact animals, serum LH concentrations, measured 24 h after the GnRH-A injection, were higher in the GnRH-A group than in saline controls on day 1, but not on days 7 and 28. However, alpha and LH beta mRNA levels were higher in the GnRH-A-treated animals than in saline controls only on day 28, but not on days 1 and 7, however, in T-replaced castrated rats, in which testicular feedback to the pituitary was clamped by orchiectomy and replacement with a fixed dose of exogenous T, GnRH-A decreased serum LH and LH beta mRNA levels compared to those in saline controls. alpha mRNA levels were, however, not different between GnRH-A- and saline-treated animals at any time. We conclude that 1) an early increase in serum LH after 1 day of GnRH-A treatment probably reflects the release of preformed LH rather than increased synthesis; 2) in T-replaced castrated animals where the testicular feedback is clamped, GnRH-A-induced down-regulation of LH can be explained by a decrease in LH beta mRNA; and 3) differences in the LH subunit responses of intact and T-replaced castrated animals provide further evidence for testicular modulation of the LH response to GnRH-A.
Texture-Based Photogrammetry Accuracy on Curved Surfaces

Photogrammetry is a preferred technique for noncontact measurement of flexible structures, such as large membranes and flapping-wing vehicles. Traditionally, discrete features are triangulated between photos. New techniques use the local texture of a surface to match random speckle among images. Texture-based photogrammetry allows for higher resolution surfaces, and this paper tests if the precision is similar to traditional photogrammetry. Test surfaces provide known, rounded profiles used to compare surface reconstructions. Many images are taken of an object with a projected texture, and the depth error is used to quantify the accuracy of the results. Results on surfacemeshes from800 to 2500 points show accuracy on the order of 1:2000, or nearly that of one pixel. Camera locations had a surprisingly minor effect on surface quality. There is a slight correlation of more parallel views tomore points on the surface. To show that the technique extends to practical use, results are shown for aflapping cycle of amembranewing.Dense surfacemeshes are important for higherfidelitymodels in computational fluid dynamics and finite element analysis.
Temporal dynamics of soil spatial heterogeneity in sagebrush-wheatgrass steppe during a growing season

Variability in five soil resources essential for plant growth (NH4 +, NO3 -, P, K and soil moisture) was quantified using univariate, multivariate and geostatistical techniques in a sagebrush-grass steppe ecosystem at three times (early April, June and August) during the 1994 growing season. Samples were collected every meter in a 10 × 10-m ‘macrogrid’, every 20 cm within nested 1 × 1-m ‘minigrids’, and every 3 cm within additionally nested 15 × 15-cm ‘microgrids’. Strong autocorrelation for all variables in the three sample periods was only found over distances less than 2 m, indicating that patches of high internal uniformity in this soil were smaller than 2 m during the growing season. Differences in semivariograms between sample periods were most pronounced for NO3 -, NH4 + and soil moisture, variables that we consider to primarily limit plant growth in this system. The distance over which sample points were autocorrelated for NO3 -, NH4 + and soil moisture increased from April to June. In contrast P and K, which are relatively more abundant at the study site, exhibited relatively constant semivariance patterns over the three sample periods. Weak correlation was found between samples collected in the three sample periods for N and soil moisture indicating that the spatial pattern of these limiting resources changed between sample periods. However, P and K had highly significant correlations (p<0.00001) among sample periods, indicating that the distributional patterns of these relatively more abundant resources remained rather constant. There were strong negative correlations between P and K and distance from the base of shrubs for all sample times (p<0.001), indicating an increase in P and K close to shrubs. Similar strong negative correlations were not found between distance from the shrubs and levels of NH4 +, NO3 -, or soil moisture, nor for any soil variable and distance from perennial tussock grasses. Changes in patterns of nutrient and soil moisture variability within a growing season suggest that not only must plants acquire soil resources that vary in time and space, but that they may also have to adjust to different scales of resource patchiness during the season.
Reversible inhibition of (Na+ + K+)-ATPase with a cardiac glycoside.

Abstract The effect of a semisynthetic cardiac glycoside, Actinogen® (Ay22241), on Na + | K + -ATPase was studied. Ay22241 was found to be as an effective inhibitor of the enzyme as ouabain, Ay22241 inhibition was a time dependent process and was completely reversible. While ouabain inhibition was also time dependent, it was only partially reversible. This reversibility with Ay22241 should make it a useful tool in studying the mode of action of cardiac glycosides.
Growth-factor-inducible gene expression in senescent human fibroblasts

Human diploid fibroblasts undergo only a finite number of population doublings in culture. At the end of their life span in culture, human fibroblasts enter an irreversible quiescent state, a process termed cellular senescence. Senescent cells fail to proliferate despite an adequate supply of growth factors in the medium and no apparent change in the number or binding properties of cellular growth factor receptors. In proliferating fibroblast cultures, growth factors have been shown to induce the expression of several genes (growth-related genes). In this report, we review some of our findings on the expression of growth-related genes in senescent cells. We find that the mRNAs for some growth-related genes are not induced by growth factors in senescent cells. By contrast, the mRNAs for other such genes actually increase after human fibroblasts have undergone senescence, although these mRNAs are not necessarily translated efficiently. Our results indicate that multiple changes in gene expression occur during cellular senescence and suggest that the failure to proliferate is a consequence of a more complex change in cellular phenotype, akin to the cessation of proliferation that accompanies terminal differentiation.
Velocity-Based Movement Modeling for Individual and Population Level Inference

Understanding animal movement and resource selection provides important information about the ecology of the animal, but an animal's movement and behavior are not typically constant in time. We present a velocity-based approach for modeling animal movement in space and time that allows for temporal heterogeneity in an animal's response to the environment, allows for temporal irregularity in telemetry data, and accounts for the uncertainty in the location information. Population-level inference on movement patterns and resource selection can then be made through cluster analysis of the parameters related to movement and behavior. We illustrate this approach through a study of northern fur seal (Callorhinus ursinus) movement in the Bering Sea, Alaska, USA. Results show sex differentiation, with female northern fur seals exhibiting stronger response to environmental variables.
Genetic Etiologies of Glaucoma

Glaucoma can be inherited as a mendelian autosomal-dominant or autosomal-recessive trait, or as a complex multifactorial trait. Genetic approaches have helped define the underlying molecular events responsible for some mendelian forms of the disease and have identified the chromosome locations of genes that are likely to contribute to common complex forms. Future directions include the discovery of new glaucoma genes, determining the clinical phenotypes associated with specific genes and mutations, investigating environmental factors that may contribute to the disease, investigating gene-environment interactions and gene-gene interactions, and developing a mutation database that can be used for diagnostic and prognostic testing.
Gold Price, Neural Networks and Genetic Algorithm

Economic theory has failed to provide sufficient explanation of the dynamic path of price movement over time. Therefore, the use of any linear or non-linear functional form to model the gold price movement is bound to be arbitrary in nature. Neural Networks equipped with genetic algorithm have the advantage of simulating the non-linear models when little a priori knowledge of the structure of problem domains exist. Studies suggest that such a system provides better predictions when compared with traditional econometric models. The NeuroGenetic Optimizer software is applied to the NYMEX database of daily gold cash price covering 12/31/1974–12/31/1998 period. Among different methods, back-propagation neural networks with genetic algorithms is used to predict gold price movement. The results indicate that prices in the past, up to 36 days, strongly affect the gold prices of the future. This confirms the fact that there is short-term time dependence in gold price movements.
Kinetic study of neutral lead cluster reactions

Kinetic studies of the reactions of neutral lead clusters with NO2, NO and O2 were performed at 300 K. Reaction with NO2 is rapid, with the observed second-order rate constants for most clusters being between 0.2 and 5 × 10−11 cm3/s. There is a general trend of increasing rate with cluster size, although a few clusters display unusually high or low rates compared to ones of neighboring size. The reactions with NO are considerably slower by factors ranging from about 5 to 10. Reaction products are observed by laser ionization at 193 and 222 nm in conjunction with time-of-flight mass spectrometry. At lower fluence, the association products Pb x (NO2)+ and Pb x (NO2) 2 + are observed in the case of reactions with NO2. At higher laser fluence, Pb + and Pb x O −1+ dominate the mass spectra of Pb x reactions with NO2, showing that the products fragment to more stable oxides. No reaction with oxygen was observed for any cluster, setting upper limits on the rates of 5 × 10−14 cm3/s.
N D Solution of the n -Pole Problem

The explicit solution of the $n$-pole problem in relativistic partial-wave dispersion relations is shown to be a simple generalization of the potential-scattering results of Nyman. The solution and its application to self-consistent $S$-matrix calculations is discussed.
Spin-singlet to spin-polarized phase transition at ν = {2}/{3}: flux-trading in action

Abstract We analyze the phase transition between spin-singlet and spin-polarized states which occurs at ν = 2 3 . The basic strategy is to use adiabatic flux-trading arguments to relate this transition to the analogous transition at ν = 2. The transition is found to be similar to a transition in ferromagnets. In our analysis, we find two possible scenarios. In one, the transition is first-order, in agreement with experimental and numerical studies of the ν = 2 3 transition. In the other, we find a second-order transition to a partially polarized state followed by a second-order transition to a fully polarized state. This picture is in qualitative agreement with experiments on the ν = 4 3 state, the particle-hole conjugate of ν = 2 3 . We analyze the edge modes which propagate at the boundaries between regions of different phases and show that these do not support gapless excitations. Finally, we consider the possibility of a finite-temperature compressible state with a Fermi surface which would explain the non-zero ϱxx seen in experiments.
Why the 2008 crisis was a bad crisis for new ideas

Economic crises are, theoretically, fertile ground for alternative policy-relevant ideas. Through an examination of the policy debates in the United Kingdom and the United States during the 2008 economic crisis, this article claims that the assumption of the plasticity of the policymaking environment in the wake of crises needs to be rethought. The article argues that both governments’ superficial turns towards Keynesianism, the leading alternative policy idea, were undermined by three factors. First, the crisis was subject to two competing conceptualisations of its underlying material reality — the crisis as deep recession vs the crisis as insurmountable public debt — and as the crisis unfolded, the former lost ground to the latter. While the first interpretation of the crisis opened space for the Keynesian tool of expansionary fiscal policy, proponents of the second understanding of the crisis rejected the appropriateness of this tool. Second, even if the crisis-as-recession interpretation had carried the day, fiscal policy had been discredited over the course of several decades in favour of monetary policy, making it unlikely that fiscal policy would be judged successful regardless. Third, over the same period, monetary policy had increased its institutional strength via the growing influence of central banks in economic policymaking.
Simulation codes for light-ion diode modeling

The computational tools used in the investigation of light-ion diode physics at Sandia National Laboratories are described. Applied-B ion diodes are used to generate intense beams of ions and focus these beams onto targets as part of Sandia's inertial confinement fusion program. Computer codes are used to simulate the energy storage and pulse forming sections of the accelerator and the power flow and coupling into the diode where the ion beam is generated. Other codes are used to calculate the applied magnetic field diffusion in the diode region, the electromagnetic fluctuations in the anode-cathode gap, the subsequent beam divergence, the beam propagation, and response of various beam diagnostics. These codes are described and some typical results are shown.
Functional components versus mechanical units in descriptive morphology

The concept of functional components was initially proposed by van der Klaauw ('45, '52) to indicate overlap of functional influences particularly in mammalian skulls; his analysis marked a departure from the study of single characters to that of function-modified systems. A very similar set of terms is now coming into vogue to describe the mechanically separable components of highly kinetic fish, amphibian and reptilian skulls. In these cases the term functional unit often pertains only to the musculo-skeletal system and is utilized during the process of description; it is often applied before a complete functional analysis has been carried out. Yet, any structure tends to be affected by the influence of multiple functions, and any function will almost certainly affect multiple characteristics of the animal. Since functional components overlap, the term should not be used to label an essentially topographical dissection of the animal. It cannot be expected that each loosely connected component of a kinetic skull subserves as a single “function,” and that this function does not overlap onto other units. It is suggested that the term mechanical unit be substituted as a label for the mechanical sub-divisions often utilized to organize descriptions. The concept of functional units in the original sense then remains available as an analytical tool.
Effect of chronic ethanol consumption on respiratory and glycolytic activities of rat periportal and perivenous hepatocytes.

Abstract Previous studies (Ivesteret al., Arch. Biochem. Biophys.322, 14–21, 1995) have established that periportal and perivenous hepatocytes isolated from ethanol-fed rats demonstrate lower ATP concentrations than those in control preparations when the cells are maintained at very low oxygen tension. In the present investigation, experiments were implemented with periportal and perivenous hepatocytes to determine the effects of chronic ethanol consumption on cellular respiratory and glycolytic activities, since both contribute to maintenance of the energy state of the liver cell. Both periportal and perivenous hepatocytes from ethanol-fed rats demonstrated significantly increased, rather than decreased, respiratory activity when monitored with oxygen concentrations ranging from 16 to 140 μM. Whole liver hepatocytes from control and ethanol-fed animals demonstrated equivalent oxygen utilization, however. Glycolytic activity, monitored by lactate + pyruvate concentrations obtained after both anaerobic and aerobic incubation protocols, was decreased in both cell types from ethanol-fed animals. The glycogen concentrations in freshly isolated periportal and perivenous hepatocytes were also decreased eight- and sevenfold, respectively, as compared with control preparations. Incubation under anaerobic conditions resulted in almost complete depletion of glycogen in both cell types. These observations suggest the possibility that the decreased energy state observed in hepatocytes from ethanol-fed animals is related to a depression in anaerobic glycolysis due to depletion of the endogenous substrate, glycogen.
Adenohypophysial-thyroid activity of the tiger salamander, Ambystoma tigrinum, as a function of metamorphosis and captivity.

The aim of this study was to determine the timing of adeno-hypophysial activation during metamorphosis of the tiger salamander, Ambystoma tigrinum. It consisted of two parts: (1) determination of plasma thyroid hormone concentrations and analysis of thyroid gland histology as a function of metamorphic stage and (2) analysis of the time-course of uptake of 125I by the thyroids during metamorphosis as an indicator of endogenous thyrotropin (TSH) levels. Significant increases in both triiodothyronine (T3) and thyroxine (T4) first were evident at the onset of metamorphic climax (stage II). Maximum levels of both hormones were not observed, however, until the completion of gill resorption (stage VII). No changes in thyroid histology were observed that could be unambiguously related to metamorphic transformation. The thyroids accumulated 125I in a slow but linear fashion in premetamorphic larvae (stage I). However, uptake exhibited a rapid peak during early climax (stage II), before maximum concentrations of thyroid hormones were observed. In addition, uptake was maintained above premetamorphic levels at stage VII, in conjunction with maximum levels of T4 and T3. Captivity alone produced a small but significant increase in plasma concentrations of T3. It produced no significant effect on either thyroid histology or uptake of 125I. These results indicate that adenohypophysial activation occurs rapidly and is maximal at the onset of metamorphic climax.
On the transverse wave propagation in orthotropic timoshenko bars

Abstract The equation for flexural vibrations of rods of orthotropic material is established, analogous to that of Timoshenko for isotropic material. It is shown that, for some anisotropic materials, the correction due to rotatory inertia and shear may be one order of magnitude greater than the correction in the isotropic case. Graphs are given of the phase velocity versus inverse wavelength for various materials.
A Packed Graphite Cell for Thin-Layer Electrochemistry

Abstract A thin-layer electrochemical cell, which consists of a bed of graphite granules, is described and evaluated for chronopotentiometric experiments. The dependence of transition time on concentration is linear (within 3%) for a single component and the transition time of a component is independent of the concentrations of other electroactive materials in the solution.
Universal Design: A Tool to Help College Students with Asperger's Syndrome Engage on Campus.

N THIS TIME OF EXTRAORDINARY societal diversity, economic change, and global competition, numerous organizations support the use of higher education as a systemic intervention for members of devalued groups, both nationally and internationally. Despite their significant impact on colleges and universities, one of the most overlooked groups being encouraged by these organizations to par-ticipate in higher education is individuals with disabili-ties. The transition to the college environment presents challenges to all students; however, this transition is particularly diffi cult for students with disabilities, espe-cially those with Asperger’s syndrome (AS), a disorder on the autism spectrum. To understand how students on the autism spectrum can transition successfully to the college environment, one must be aware of the core defi cits that defi ne autism spectrum disorder and how organizational barriers may impede such students’ transition to college. Many of the countless strategies and techniques suggested to assist individuals on the spectrum can help them to succeed academically, but very few focus on how to create an inclusive environ-ment conducive to increased community engagement for these students. Therefore, the authors of this article examine the potential barriers these students experience and outline how universal design, when used effec-tively, can be a valuable tool to increase engagement.
Measurements of coronary plasma and pericardial infusate adenosine concentrations during exercise in conscious dog: Relationship to myocardial oxygen consumption and coronary blood flow☆

A conscious dog model was employed to evaluate the relationships among myocardial oxygen consumption (MVO2), myocardial adenosine release and coronary blood flow (CBF) during graded treadmill exercise. Two methods were utilized simultaneously as indexes of changes in interstitial adenosine concentrations, (1) a pericardial infusate technique and (2) the measurement of arterial-coronary sinus plasma adenosine concentration differences. Graded exercise was associated with graded increases in MVO2, CBF, pericardial infusate adenosine concentration (PI Ado) and adenosine washout in coronary plasma. Regression analysis demonstrated significant linear relationships for MVO2 v. CBF (r = 0.78, P < 0.01), MVO2 v. PI Ado (r = 0.52, P < 0.01), and PI Ado v. CBF (r = 0.76, P < 0.01). Coronary plasma adenosine arterio-sinus differences, sinus plasma concentrations, and net washout of adenosine also increased with graded exercise, however, a significant inter-animal variance was noted. These data suggest that the plasma adenosine assay is capable of detecting directional (qualitative) changes associated with changes in cardiac metabolism, however, it may not be reliable as a quantitative indicator of interstitial adenosine concentrations due to multiple factors which may influence the plasma adenosine pool. The pericardial infusate technique, which presumably represents a model of diffusion, is relatively invariant by comparison. The results demonstrate a significant correlation among MVO2, PI Ado and CBF, and thereby provide support to the hypothesis that adenosine is a major factor in the coupling of myocardial oxygen demand to oxygen supply under physiological conditions.
Observation of nonuniform precipitation of Mn in an AlMg ingot

Abstract Dispersoids containing manganese precipitate nonuniformly during thermal treatment of AlMg alloys depending upon the temperature of preheating. Precipitation is sparse between dendrite arms, copious near the arm boundaries, and near zero at the center of the arms. This phenomenon is attributed to the competing effects of Mg segregation on the solubility of Mn and of Mn segregation on the availability of Mn to precipitate.
Tissue Adequacy for Ancillary Studies Beyond Frozen Section A Potential Method for Improving Diagnostic and Therapeutic Results

The evolving nature of medicine has created new challenges in numerous aspects of the practice of pathology. The development of less invasive procedures, the generation of better diagnostic tools, and the recognition of prognostic markers have contributed to these challenges. Between 42.7% and 65.0% of intraoperative consultations are performed to identify or type a neoplastic process. We instituted a reporting requirement on our intraoperative consultations to provide an assessment of adequacy. The assessment of adequacy was subjective by its very nature and was based on the possible uses for the submitted tissue. A total of 3086 intraoperative consultations were performed over a 13-month period. Sixty-two cases were determined to be insufficient for ancillary studies; 52 of these cases were remedied by the surgeon during the original diagnostic procedure. We have instituted a new assessment for intraoperative consultations to optimize the tissue obtained and reduce the need for additional procedures.
Functional Group Selective Derivatization and Gas-Phase Fragmentation Reactions of Plasmalogen Glycerophospholipids

A reaction strategy involving functional group selective modification of the O-alkenyl-ether double bond within plasmenyl ether containing lipids using iodine and methanol, in conjunction with functional group selective derivatization of amine-containing lipids using a novel 13C1-S,S′-dimethylthiobutanoylhydroxysuccinimide ester (13C1-DMBNHS) reagent, is shown to improve the capabilities of ‘shotgun’ high resolution/accurate mass spectrometry for comprehensive lipidome analysis. Importantly, the characteristic mass shifts introduced as a result of these derivatization reactions enables the resolution and unambiguous identification of isobaric mass plasmenyl- and plasmanyl-ether containing lipid species from within crude complex lipid extracts, without need for chromatographic fractionation or additional lipid extraction steps prior to analysis. Additionally, the positive ionization mode tandem mass spectrometry fragmentation behavior of the derivatized plasmenyl ether containing glycerophosphocholine and glycerophosphoethanolamine lipids are shown to yield abundant characteristic product ions that directly enable the assignment of their molecular lipid identities.
Suspending Agent Effects on Steroid Suspension Dissolution Profiles

Dissolution profiles and particle-size analyses were determined for two lots of prednisolone acetate. The effects of common suspending agents on dissolution and particle-size distributions of these suspensions also were investigated. Lot-to-lot variation in the prednisolone acetate dissolution rate was observed and was apparently related to the percentage of fine particles within the distribution. Carboxymethylcellulose sodium inhibition of prednisolone acetate dissolution occurred with only one lot of raw material and seemed to be related to aggregation of the fine particles. Hydroxypropyl methylcellulose inhibited both prednisolone acetate lots and was observed with or without small particle aggregation. The dissolution variations observed have important implications in suspension formulation.
The flexible exchange basket: a macroeconomic analysis

Abstract This paper constructs and analyzes a multi-country stochastic equilibrium framework suitable for analyzing the behavior of an economy which pursues a flexible exchange basket policy. The framework is general enough to accommodate the special cases of (a) multilateral floating exchange rates and (b) rigid basket regimes. An important issue that is addressed in the present framework involves the composition of the optimal flexible basket versus that of the corresponding rigid basket. Such an investigation is carried out for various patterns of multilateral trade, for various types of structural disturbances, and for alternative optimality criteria.
Mental Causation versus Physical Causation: No Contest

Common sense supposes thoughts can cause bodily movements and thereby bring about changes in where the agent is or how his surroundings are. Many philosophers suppose that any such outcome is realized in a complex state of affairs involving only microparticles; that previous microphysical developments were sufficient to cause that state of affairs; hence that, barring overdetermination, causation by the mental is excluded. This paper argues that the microphysical swarm that realizes the outcome is an accident (Aristotle) or a coincidence (David Owens) and has no cause, though each component movement in it has one. Mental causation faces no competition “from below”.
HLA Class I Antigen Serves as a Receptor for Human Coronavirus OC43

Human coronaviruses are associated with acute respiratory and enteric disease in man as such their target cells are probably the epithelial cells lining the respiratory and enteric tract. Attachment of virus to specific receptors on the cell surface is a major determinant of virus tropism in pathogenesis (1). Recently, aminopeptidase-N was identified as a cell receptor for the 229e coronavirus (2). Cell receptor(s) for OC43 coronavirus have not been identified. However, it is of pathologic significance that OC43 virus shares DNA sequence homology with the two coronavirus isolates, SK and SD, from the brain of patients with multiple sclerosis (MS) (3). Probing MS and control brain with probes specific for human, murine, porcine and bovine coronavirus by in situ hybridization resulted in the detection of coronavirus RNA in 12 of 22 MS brain samples; five of which were positive with the OC43 probe (4).A study of virus-ligand interactions of OC43 with human rhabdomyosarcoma (RD) cells, which are highly suscep...
Variability of matrix effects in liquid and gas chromatography-mass spectrometry analysis of pesticide residues after QuEChERS sample preparation of different food crops.

Abstract Gas and liquid chromatography (GC and LC) coupled to mass spectrometry (MS) serve as the most powerful analytical tools commonly used to monitor pesticide residues in food, among other applications. However, both GC–MS and LC–MS are susceptible to matrix effects which can adversely affect quantification depending on the analyte, matrix, sample preparation, instrumentation, and operating conditions. Among the approaches that reduce matrix effects, the most common in pesticide residue applications is matrix-matched calibration because it is relatively inexpensive and simple. Also, it has been shown to work well during method validation when fortified samples are exactly matched with samples used for calibration. However, the quality of matrix-matched results in real-world analyses depends on the consistency of matrix effects among diverse samples. In this study, the variability of matrix effects was measured for 38 representative pesticides in 20 samples each (including different varieties) of rice, orange, apple, and spinach extracted using the “quick, easy, cheap, effective, rugged, and safe” (QuEChERS) method for analysis by LC–MS/MS and low-pressure GC–MS. Using LC–MS/MS, only oranges gave >20% matrix effects for a few pesticides. GC–MS exhibited larger matrix effects, but as in LC–MS/MS, the differences were reasonably consistent among the 20 samples tested. Main conclusions of this study are that for the conditions utilized: (1) matrix-matching was not needed for most pesticides in the simpler food matrices; and (2) for the more complex orange matrix, acceptably accurate quantitative results were achieved by using matrix-matching even with a different sample of the same type. However, full confidence cannot be extended to matrix-matched results, and for consequential applications such as regulatory enforcement, confirmatory analyses using alternate quantitative determinations should also be conducted.
Structure and Dynamics of Calmodulin in Solution

Abstract To characterize the dynamic behavior of calmodulin in solution, we have carried out molecular dynamics (MD) simulations of the Ca 2+ -loaded structure. The crystal structure of calmodulin was placed in a solvent sphere of radius 44A, and 6 Cl − and 22 Na + ions were included to neutralize the system and to model a 150mM salt concentration. The total number of atoms was 32,867. During the 3-ns simulation, the structure exhibits large conformational changes on the nanosecond time scale. The central α -helix, which has been shown to unwind locally upon binding of calmodulin to target proteins, bends and unwinds near residue Arg 74 . We interpret this result as a preparative step in the more extensive structural transition observed in the "flexible linker" region 74–82 of the central helix upon complex formation. The major structural change is a reorientation of the two Ca 2+ -binding domains with respect to each other and a rearrangement of α -helices in the N-terminus domain that makes the hydrophobic target peptide binding site more accessible. This structural rearrangement brings the domains to a more favorable position for target binding, poised to achieve the orientation observed in the complex of calmodulin with myosin light-chain kinase. Analysis of solvent structure reveals an inhomogeneity in the mobility of water in the vicinity of the protein, which is attributable to the hydrophobic effect exerted by calmodulin's binding sites for target peptides.
Structural biology: Signalling from disordered proteins.

The discovery that a disordered protein can transmit signals between two binding sites calls into question the idea that communication within proteins requires a specific structural pathway linking such sites. See Letter p.390 Cellular function relies on intricate signalling networks incorporating protein signalling hubs that interact with several partners in order to modulate multiple downstream signals. This study of one such hub, the adenovirus early region 1A (E1A) oncoprotein, uses novel single molecule FRET measurements to overcome aggregation problems and to directly probe the allosteric interactions of E1A with two key partners. The results reveal a striking cooperativity modulation, regulated by multiple interactions and availability of E1A interaction motifs. Such a modulation of allosteric interactions may be a common feature of intrinsically disordered hub proteins.
Prostaglandin H synthase 2 is expressed abnormally in human colon cancer: evidence for a transcriptional effect

Abstract Evidence from epidemiological studies, clinical trials, and animal experiments indicates that inhibitors of prostaglandin synthesis lower the risk of colon cancer. We tested the hypothesis that abnormal expression of prostaglandin H synthase 2 (PHS-2), which can be induced by oncogenes and tumor promoters, occurs during colon carcinogenesis by examining its level in colon tumors. Human colon cancers were found to have an increased expression of PHS-2 mRNA compared with normal colon specimens from the same patient (n = 5). In situ hybridization showed that the neoplastic colonocytes had increased expression of PHS-2 (n = 4). Additionally, five colon cancer cell lines were shown to express high levels of PHS-2 mRNA even in the absence of a known inducer of PHS-2. To study the basis for this increased gene expression, we transfected a colon cancer cell line, HCT-116, with a reporter gene containing 2.0 kb of the 5' regulatory sequence of the PHS-2 gene. Constitutive transcription of the reporter gene was observed, whereas normal control cell lines transcribed the reporter only in response to an exogenous agonist. We conclude that PHS-2 is transcribed abnormally in human colon cancers and that this may be one mechanism by which prostaglandins or related compounds that support carcinogenesis are generated.
Ribosomal RNA pseudouridines and pseudouridine synthases

Pseudouridines are found in virtually all ribosomal RNAs but their function is unknown. There are four to eight times more pseudouridines in eukaryotes than in eubacteria. Mapping 19 Haloarcula marismortui pseudouridines on the three-dimensional 50S subunit does not show clustering. In bacteria, specific enzymes choose the site of pseudouridine formation. In eukaryotes, and probably also in archaea, selection and modification is done by a guide RNA-protein complex. No unique specific role for ribosomal pseudouridines has been identified. We propose that pseudouridine's function is as a molecular glue to stabilize required RNA conformations that would otherwise be too flexible.
Compositional changes in Fe-Cr-Ni alloys under proton bombardment at elevated temperatures

Abstract Compositional redistribution in austenitic Fe-Cr-Ni alloys during energetic proton bombardment has been calculated as a function of time, temperature, and ion energy, using a kinetic model of radiation-induced segregation recently developed for ternary alloys. The effect of spatial nonuniformity in damage rates was taken into account and found to have a peculiar effect on the redistribution of the alloying elements. Enrichment of Ni occurs at the bombarded surface and in the bulk beyond the damage range, whereas Fe and Cr are enriched in the peak-damage region at the expense of their depletion in regions near the surface and beyond the damage range. These compositional changes can lead to local phase transformation, since the composition of local regions of the alloy is shifted away from the initial composition into different parts of the multicomponent phase diagram. The stability of the austenite phase in the sub-surface and post-range regions is enhanced by irradiation, while the austenite-to-ferrite transformation takes place in the peak-damage region.
Spectroscopy of a Balmer-dominated filament in the Cygnus Loop with the Hopkins Ultraviolet Telescope

A fair UV spectrum of a nonradiative filament in the Cygnus Loop covering the wavelength range 830-1860 A at 3.5-A resolution was obtained using the Hopkins Ultraviolet Telescope (HUT) on the Astro-1 space shuttle mission. Nonradiative shock models which include a more sophisticated treatment of Lyman line transfer are calculated. It is found that the HUT spectrum can be explained in terms of a shock with velocity 175-185 km/s propagating into a low-density medium. This shock velocity can be reconciled with the 135-km/s width of the broad component of H-alpha in this filament if equilibration of the postshock electron and ion temperatures proceeds much more rapidly than Coulomb equilibration time scales. The time required for a 180-km/s shock to develop a partial recombination zone is short, about 200 yr if n is approximately equal to 2/cu cm. This suggests that the shock is decelerating as it encounters denser material. The current analysis patently favors rapid equilibration of electrons and ions behind the shock.
Addenda to the radiology report: what are we trying to convey?

Purpose The aims of this paper are to describe addenda to radiology reports and to discuss the communication gaps in radiology addenda reaching referring physicians. The authors examine impediments to compliance with an addendum policy and suggest possible solutions. Methods A total of 62,500 radiology reports were reviewed to analyze the occurrence of report addenda. Addenda types were separated into clinical, generated by radiologists, and administrative (for billing or regulatory reasons). Two radiologists reviewed all clinical addenda and classified them as significant or not significant. Significant addenda were further analyzed for various aspects. An e-mail survey was also conducted to assess prevailing practices in academic departments of radiology. Results There were 1,069 reports with addenda (1.7%). Of these, 575 were generated by radiologists. Forty-nine (8.5%) were for clinically significant errors and 526 (91.5%) were not. Of the 49 significant addenda, 9 (18%) were fully compliant with departmental addendum policies, 27 (55%) were noncompliant, and 13 (27%) were partially compliant. Of the 49 clinically significant addenda, 17 (55%) were dictated within 1 hour and 40 (82%) within 24 hours of the finalized original reports. Conclusions Poor compliance with an addendum policy was found. The reasons for noncompliance and possible remedies are discussed, with the hope of beginning a dialogue in the radiology literature on the risks of poor communication processes and the benefits of full implementation of well thought-out addendum policies.
Stimulant Treatment for Children: A Community Perspective

ABSTRACT Objective To examine the use of prescribed stimulants in relation to research diagnoses of attention-deficit hyperactivity disorder (ADHD) in a community sample of children. Method Data from 4 annual waves of interviews with 9- to 16-year-olds from the Great Smoky Mountains Study were analyzed. Results Over a 4-year period, almost three quarters of children with an unequivocal diagnosis of ADHD received stimulant medications. However, girls and older children with ADHD were less likely to receive such treatment. Most children with impairing ADHD symptoms not meeting full criteria for DSM-III-R ADHD did not receive stimulant treatment. Stimulant treatment in this group was significantly related to the level of symptoms reported by parents and teachers and was much more common in individuals who met criteria for oppositional defiant disorder. The majority of individuals who received stimulants were never reported by their parents to have any impairing ADHD symptoms. They did have higher levels of nonimpairing parent-reported ADHD symptoms, higher levels of teacher-reported ADHD symptoms, and interviewer-observed ADHD behaviors, but these typically fell far below the threshold for a DSM-III-R diagnosis of ADHD. Conclusions In this area of the Great Smoky Mountains, stimulant treatment was being used in ways substantially inconsistent with current diagnostic guidelines.
Acid Phosphatase in the Digestive Vacuoles and Lysosomes of Paramecium caudatum: A Timed Study†

Enzyme cytochemistry was used to determine when acid phosphatase (AcPase) becomes associated with the digestive vacuoles (DVs) of axenically grown Paramecium caudatum that were pulsed with latex beads for 2–3 min. When cells were incubated in the Gomori medium, AcPase was not observed in the discoidal vesicles, the acidosomes, and the newly released DVs up to 3 min old or in most DVs 3–6 min old. The number of AcPase-positive DVs increased to 56% when DVs were 12–18 min old. Similar results were obtained using the napthol AS-TR phosphate-hexaotized rosanilin method at the light microscopic level where hundreds of DVs were scored though the maximal level of positive DVs obtained by this method was lower. In addition to DVs of specific ages, AcPase was found in ER, in some Golgi vesicles, and small vesicles similar in diameter to Golgi vesicles which may represent primary lysosomes in this ciliate. Larger vesicles abundant near the DV-II were only partially filled with reaction product. These vesicles, which could be identified by their paracrystalline sheets and a prominent glycocalyx lining the luminal surface of their membranes, fit the definition for secondary lysosomes. These results, which indicate that lysosomes fuse with DVs only after they have attained a certain age, suggest the existence of specific recognition factors on the membranes of secondary lysosomes as well as DV-II.