cssi/SciSciGPT-SciSciNet huggingface dataset:
hcapca: Automated Hierarchical Clustering and Principal Component Analysis of Large Metabolomic Datasets in R

Microbial natural product discovery programs face two main challenges today: rapidly prioritizing strains for discovering new molecules and avoiding the rediscovery of already known molecules. Typically, these problems have been tackled using biological assays to identify promising strains and techniques that model variance in a dataset such as PCA to highlight novel chemistry. While these tools have shown successful outcomes in the past, datasets are becoming much larger and require a new approach. Since PCA models are dependent on the members of the group being modeled, large datasets with many members make it difficult to accurately model the variance in the data. Our tool, hcapca, first groups strains based on the similarity of their chemical composition, and then applies PCA to the smaller sub-groups yielding more robust PCA models. This allows for scalable chemical comparisons among hundreds of strains with thousands of molecular features. As a proof of concept, we applied our open-source tool to a dataset with 1046 LCMS profiles of marine invertebrate associated bacteria and discovered three new analogs of an established anticancer agent from one promising strain.
The effects of corporate governance and managerial compensation on financial fraud: Evidence from China

The purpose of this study is to examine whether financial crises influence the effects of manager market competition and cash compensation on the likelihood of listed firms’ fraudulent financial reporting in China. We use a logistic regression model to analyze a very large sample of 1,088 Chinese listed firms from 2008 to 2018. The main findings are as follows: first, manager market competition is negatively associated with the probability of committing fraud. Second, managers’ cash compensation is negatively related to the likelihood of financial fraud. These findings suggest that (1) strong manager market competition can regulate Chinese top managers effectively; (2) higher cash compensation and a good governance mechanism can encourage top managers to deter financial fraud.
Skirting SLR's language trap: reframing the 'systematic' vs 'traditional' literature review opposition as a continuum

I was pleased to be invited to comment on Boell and CecezKecmanovic’s paper on Systematic Literature Reviews (SLR). Not only do I find the JIT debates very valuable in that they encourage reflection on our practices as IS researchers, but I also found that this particular paper highlighted a distinction between systematic and traditional literature reviews that had not quite entered by consciousness yet. As such, I learned a lot from engaging with the authors’ arguments, as well as reading some of the literature on this topic. I would therefore like to thank the authors for prompting this thought-provoking and important debate.
Paradigm Regained: Abstraction Mechanisms for Access Control

Access control systems must be evaluated in part on how well they enable one to distribute the access rights needed for cooperation, while simultaneously limiting the propagation of rights which would create vulnerabilities. Analysis to date implicitly assumes access is controlled only by manipulating a system’s protection state – the arrangement of the access graph. Because of the limitations of this analysis, capability systems have been ”proven” unable to enforce some basic policies: revocation, confinement, and the *-properties (explained in the text).
Short-Term Plasticity Shapes the Response to Simulated Normal and Parkinsonian Input Patterns in the Globus Pallidus

Basal ganglia structures show strong activity modulation during movement and synchronous bursting in Parkinson's disease. Recent work has shown that short-term synaptic plasticity (STP) can play an important role in the effect of temporal activity patterns on postsynaptic targets. To determine the role of STP in the subthalamic nucleus (STN) to globus pallidus (GP) connection, which has been suggested to underlie rhythmical bursting in Parkinson's disease, we first measured STP using trains of electrical input stimulation in vitro. We found that STN inputs to GP typically show both facilitation and depression with input frequencies of 10-100 Hz and that facilitation is dominant for the first few inputs in a train but that depression takes over subsequently. We quantified the strength and time course of facilitation and depression using a computational model of STP. Using the STP model, we constructed synaptic conductance patterns of normal and Parkinsonian STN activity and applied these conductances to GP neurons in vitro using the technique of dynamic clamping. We show that STP controls the slope and shape of the function describing the steady-state level of GP neuron firing in response to different levels of STN input. In addition, we show that STP modulates responses of GP neurons to bursts and pauses in the input pattern. These findings indicate that STP plays an important role in modulating both spike rates and temporal patterns of GP activity in the normal state, as well as in Parkinson's disease.
Helical magnetism and structural anomalies in triangular lattice α-SrCr2O4.

α-SrCr2O4 has a triangular planar lattice of d3 Cr3 + made from edge sharing CrO6 octahedra; the plane shows a very small orthorhombic distortion from hexagonal symmetry. With a Weiss temperature of − 596 K and a three-dimensional magnetic ordering temperature of 43 K, the magnetic system is quasi-two-dimensional and frustrated. Neutron powder diffraction shows that the ordered state is an incommensurate helical magnet, with an in-plane propagation vector of k = (0, 0.3217(8), 0). Temperature dependent synchrotron powder diffraction characterization of the structure shows an increase in the inter-plane spacing on cooling below 100 K and an inflection in the cell parameters at the magnetic ordering temperature. These anomalies indicate the presence of a moderate degree of magnetostructural coupling.
Stuttering and level of linguistic demand: The Stocker probe

Abstract One of the basic assumptions underlying the Stocker Probe Technique for evaluation and treatment of stuttering in children is that stuttering frequency increases as the level of linguistic demand increases. In the study reported in this article, stuttering and nonstuttering children were administered the 50 evaluation items of the Stocker Probe Technique (1980 ed., rev.). Results of the study were that the degree to which stuttering frequency increased at higher levels of lingustic demand depended upon the particular test administration and scoring procedure utilized. When only one response was elicited for each test item, and when an entire response was scored as stuttered or not stuttered, stuttering frequency was greater at higher levels of linguistic demand. These findings were similar to those reported by Stocker. When performance on test items was partially equated for amount of speech, and when stuttering was scored in the more conventional terms of percent words stuttered, stuttering frequency did not differ significantly among the various levels of linguistic demand. This result was applicable for both stuttering and nonstuttering children, and for both younger and older children.
Optimizing Strategic Allocation of Vehicles for One-Way Car-sharing Systems Under Demand Uncertainty

Car-sharing offers an environmentally sustainable, socially responsible and economically feasible mobility form in which a fleet of shared-use vehicles in a number of locations can be accessed and used by many people on as-needed basis at an hourly or mileage rate. To ensure its sustainability, car-sharing operators must be able to effectively manage dynamic and uncertain demands, and make the best decisions on strategic vehicle allocation and operational vehicle reallocation both in time and space to improve their profits while keeping costs under control. This paper develops a stochastic optimization method to optimize strategic allocation of vehicles for one-way car-sharing systems under demand uncertainty. A multi-stage stochastic linear programming model is developed and solved for use in the context of car-sharing. A seven-stage experimental network study is conducted. Numerical results and computational insights are discussed.
Contextual Predictors of Cumulative Biological Risk: Segregation and Allostatic Load†

Objectives Segregation is considered to be a fundamental cause of race/ethnic disparities in health. However, very few studies have tested whether levels of segregation are related to health outcomes using multilevel data and appropriate methodologies. In this study, we investigate the relationships between two distinct dimensions of segregation and allostatic load to determine whether the experiences of individuals in segregated neighborhoods are related to allostatic load as a possible predisease indicator. Methods To test our hypotheses, we utilized publicly available data from the National Health and Nutrition Examination Survey III, 1988–1994. We utilized random-intercept hierarchical generalized Poisson regression models to conduct our multivariate analyses. Results We find that inflammatory response is related to both the evenness and exposure domains of segregation. That is, both the unequal distribution of minority groups over areal units as well as the degree of potential contact between minority and majority group members are related to these predisease pathways. Conclusions In this study, we build on prior research by Massey (2004) to investigate the relationships between two distinct dimensions of segregation and allostatic load. Our results indicate that segregation is a significant predictor of allostatic load, net of individual-level characteristics.
Return to Play

Call it physical activity, call it games, or call it play. Whatever its name, it's a place we all need to return to. In the physical education, recreation, and dance professions, we need to redesign programs to address the need for and want of play that is inherent in all of us.
Simulation and emulation of biomedical instrumentation systems using object-oriented-programming

Teaching Biomedical Instrumentation Systems has been a difficult task due to the high cost of equipment. This has been most acute for undergraduate programs. With the introduction of computers and object-oriented programming in teaching laboratories it is now possible to simulate and emulate these systems easily and economically. The authors describe an undergraduate engineering course in biomedical instrumentation where object-oriented programming is used. The course explains, develops, simulates, and emulates basic biomedical instrumentation systems such as Biopotential Amplifiers, Cardiovascular Measurement Systems, and Respiratory Measurement Systems. >
Characterization of an endogenous morphine-like factor(enkephalin) in mammalian brain.

Mammalian brain extracts contain a substance, "enkephalin," which competes for opiate receptor binding in a highly selective fashion. This material behaves in opiate receptor assays as an opiate agonist, with its effects enhanced by manganese and decreased by sodium. The regional distribution of enkephalin parallels that of the opiate receptor itself. Enkephalin activity is degraded by carboxypeptidases A and B and leucinaminopeptidase as well as by chymotrypsin, but is resistant to trypsin and neuraminidase. Thus enkephalin appears to be a peptide. Gel filtration experiments indicate a molecular weight of about 1000.
Gains And Losses from an Open Line Program as Perceived by By-Passed Managers: A Case Study

The article presents the result of a survey on the attitude of lower level managers toward the open line program of the U.S. Air Force in Wiesbaden, Germany. The open line program was established t...
Optimal path planning for an autonomous robot-trailer system

In this paper the authors discuss a path planning problem for an autonomous robot-trailer system, while also including some consideration for the physical dimension of the trailer. The trailer equipped with sensing equipments is used to perform a surveillance mission among a collection of waypoint neighborhoods. The concept of a neighborhood is used to model the physical size of the actual sensors on the trailer. The problem is modeled as a Dubins Traveling Salesman Problem with Neighborhoods (DTSPN), where the neighborhoods are represented by disks. The authors firstly design a new algorithm for the Traveling Salesman Problem with Neighborhoods (TSPN), then extend this algorithm to find the shortest path for the DTSPN. The numerical study shows that the proposed algorithm can perform very well for both disjoint and overlapped disks cases.
Changes in cell gene expression in human leukemic cells persistently infected with vaccinia virus.

Abstract Persistent viral infections in vitro are useful systems to study the coevolution of virus and cell populations. Persistent infection of mouse Friend erythroleukemic cells (FEL) with vaccinia virus results in profound changes of the virus as well as of the cells. To investigate phenotypic changes of other cell types, we have established a persistent infection with vaccinia virus in a human leukemic cell Une (K562). This cell line can be induced to differentiate along the erythroid pathway synthesizing embryonic and fetal globins, thus providing a system in which specific genes can be stimulated. After serial passage, the persistently infected cells (K562 vac ) became spontaneously differentiated, as shown by the increase in the number of cells producing hemoglobin (benzidine positive cells), and resistant to superinfection. These phenotypic changes of the cells were not accompanied by changes in the viral population. Hybridization of cellular RNA with cloned embryonic and fetal globin genes indicated that uninduced K562 cells do not express these genes, whereas cells induced by hemin or butyrate express G γ (fetal globin) e and ζ (embryonic globins) genes. By contrast vaccinia infected cells spontaneously express the Gγ gene. These results demonstrate that persistent infection with vaccinia virus elicited phenotypic changes in the infected cell population; in this case the constitutive expression of fetal hemoglobin.
Crop Rotation and Tillage Effects on Soil Physical and Chemical Properties in Illinois

Published in Agron. J. 107:971–978 (2015) doi:10.2134/agronj14.0465 Available freely online through the author-supported open access option. Copyright © 2015 by the American Society of Agronomy, 5585 Guilford Road, Madison, WI 53711. All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. ABSTRACT Recent increases in corn (Zea mays L.) production in the U.S. Corn Belt have necessitated the conversion of rotations to continuous corn, and an increase in the frequency of tillage. The objective of this study was to assess the effect of rotation and tillage on soil physical and chemical properties in soils typical of Illinois. Sequences of continuous corn (CCC), 2-yr corn–soybean [Glycine max (L.) Merr.] (CS) rotation, 3-yr corn–soybean–wheat (Triticum aestivum L.) (CSW) rotation, and continuous soybean (SSS) were split into conventional tillage (CT) and no-till (NT) subplots at two Illinois sites. After 15 yr, bulk density (BD) under NT was 2.4% greater than under CT. Water aggregate stability (WAS) was 0.84 kg kg–1 under NT compared to 0.81 kg kg–1 under CT. Similarly, soil organic carbon (SOC) and total nitrogen (TN) were greater under NT than under CT with SOC values for 0 to 60 cm of 96.0 and 91.0 Mg ha–1 and TN values of 8.87 and 8.40 Mg ha–1 for NT and CT, respectively. Rotations affected WAS, TN, and K levels with WAS being greatest for the CSW rotation at 0.87 kg kg–1, decreasing with more soybean years (CS, 0.82 kg kg–1 and SSS, 0.79 kg kg–1). A similar pattern was detected for TN and exchangeable K. Results indicated that while the use of NT improved soil quality, long-term implementation of continuous corn had similar soil quality parameters to those found under a corn–soybean rotation.
Compendium of Nahuatl Grammar

Compendium of Nahuatl Grammar. Thelma D. Sullivan (translated from the Spanish by Thelma D. Sullivan and Neville Stiles and edited by Wick R. Miller and Karen Dakin). Salt Lake City: University of Utah Press, 1988. xxxi. 324pp. $25.00 (paper). ISBN 0-87480-282-2.
Radical cation intermediates in the formation of schiff bases on irradiated semiconductor powders

Abstract Photocatalytic oxidation of several primary aliphatic amines on irradiated TiO2 powders suspended in anhydrous acetonitrile led to good yields of the corresponding symmetrical N-alkylidene amines. Mechanistic electrochemical investigation of the reaction revealed intermediate formation of an immonium cation in an ECE route. This species is generated via electrooxidation of an α-amino radical formed by deprotonation of the primary oxidation product, an aminium cation radical. The influence of the metal oxide surface on radical cation reactivity is discussed.
The Schizophrenic Clients Reinforcement and Punishment for Medication Adherence

(1984). The Schizophrenic Clients Reinforcement and Punishment for Medication Adherence. Issues in Mental Health Nursing: Vol. 6, No. 1-2, pp. 173-187.
The effect of fluid mechanical stress on cellular arachidonic acid metabolism

The effect of sublytic levels of mechanical perturations of cells on cell metabolism were investigated by analyzing the products of arachidonic acid (used as a marker metabolite) in blood platelets, polymorphonuclear leucocytes, and cultured umbilical-vein endothelial cells after the suspensions of these cells were subjected to a shear stress in a modified viscometer. It is shown that the sublytic levels of mechanical stress stimulated the arachidonic acid metabolism in all these cell types. Possible biological implications of this stress-metabolism coupling are discussed.
Pigment changes and photosynthetic rates under selected wavelengths in the growing tips of Eucheuma isiforme (C. Agardh) J. Agardh var deudatum Cheney during vegetative growth

Pigment extracts (phycoerythrin and chlorophyll) and apparent photosynthetic rates under selected wavelengths for the benthic marine alga Eucheuma isiforme var denudatum are presented. Plants were sampled from March to September during vegetative growth. The study shows that (a) total pigment content exhibits a three-fold increase from young to mature plants, (b) the concentration of phycoerythrin changes from 0·36 nm/mg dry wt to 1·07 nm/mg dry wt and the chlorophyll concentration changes from 0·03 nm/mg dry wt to 0·57 nm/mg dry wt and (c) an initial phycoerythrin/chlorophyll ratio of 20 : 1 decreased to 1 : 1 during the summer months. The September ratio increased to 3 : 1. E. isiforme var denudatum exhibited strong correlations between pigment concentration and apparent photosynthetic rates. Blue and red light exhibited correlations (0·9447 and 0·7915 respectfully) to chlorophyll. Green light exhibited the strongest correlation (0·4298) to phycoerythrin. Physical environmental fluctuations during the s...
Characterization of dislocation loops in CeO2 irradiated with high energy Krypton and Xenon

In order to fully characterize the structure of dislocation loops in CeO2, ion irradiations have been performed at 800 °C on CeO2 single-crystal thin films individually using 1 MeV Kr ions and 150 keV Xe ions, both to a dose of 5 × 1014 ions/cm2. Post-irradiation TEM examination, diffraction contrast imaging and high-resolution transmission electron microscopy (HRTEM), has confirmed that the irradiation-induced dislocation loops in CeO2 were Frank loops, having an interstitial nature with {1 1 1} habit planes and a 1/3 Burgers vector. Dislocation loops were confirmed to be a stacking fault in nature through TEM observations of the interference fringes inside the loop periphery.
Characterization of complex inter-layer dielectric stack by spectroscopic ellipsometry: A simple method to reduce parameters correlations

Abstract The accurate and stable measurements of inter-layer dielectric (ILD) film thicknesses and optical properties in a multi-layer stack have been always a key factor in semiconductor development and manufacturing. Spectroscopic ellipsometry is one of the most adapted optical metrology techniques to perform such measurements but it requires the use of one of the multi-parameter non-linear optimization methods due to its indirect nature. It creates a big challenge for analysis of multi-layer structures since the number of simultaneously determined model parameters is restricted due to parameter cross-correlations. This paper describes a simple way to reduce the correlations for single-angle ellipsometric measurements when applied to monitor the thicknesses of the dielectric films (silicon oxide, ultra low-k dielectric and low-k dielectric barrier/etch stop films) in a multi-layer stack. The method is based on inclusion of a thin Ta metal layer (~ 160 A thick) into the multi-layer structure in order to suppress the inter-layer correlations, thereby allowing an accurate determination of the thicknesses of individual films in the thin-film stack. The optical characterization of all layers in the spectral range of 200–800 nm (6.20–1.55 eV) has been performed using an “additive” thin-film stack approach. The method was employed for analyzing the multi-layer ILD test stack with up to five-layer film structures in which four of the films are dielectric. The final model uniqueness and accuracy of the obtained ellipsometric solution were also verified.
A study of interstitial liquid flow in foam. Part II. Experimental verification and observations

Experimental results obtained over a wide range of variables from three different foam fractionation columns support the theory developed in Part I.
Magnetic Ordering in an Organic Polymer

We describe preparation and magnetic properties of an organic pi-conjugated polymer with very large magnetic moment and magnetic order at low temperatures. The polymer is designed with a large density of cross-links and alternating connectivity of radical modules with unequal spin quantum numbers (S), macrocyclic S = 2 and, cross-linking S = (1/2) modules, which permits large net S values for either ferromagnetic or antiferromagnetic exchange couplings between the modules. In the highly cross-linked polymer, an effective magnetic moment corresponding to an average S of about 5000 and slow reorientation of the magnetization by a small magnetic field (less than or equal to 1 oersted) below a temperature of about 10 kelvin are found. Qualitatively, this magnetic behavior is comparable to that of insulating spin glasses and blocked superparamagnets.
Negation of Paternity in Islamic Law between Liʿān and DNA Fingerprinting

This essay explores the impact of DNA fingerprinting on the Islamic law of paternity, with a particular focus on paternity negation and the continued validity of liʿān (mutual oaths of condemnation). After surveying the scriptural and legal foundations of liʿān in the Islamic legal tradition, the essay traces the introduction of DNA fingerprinting for the resolution of identity and paternity disputes in the modern period, especially in the American legal context. The essay explores the modern Muslim legal opinion on the issue by examining the statements and discussions of three scholarly councils: the Islamic Organization for Medical Sciences, the International Islamic Fiqh Academy, and the Islamic Fiqh Council. The essay argues that the modern Muslim opinion on the issue is a function of both the legal characterization of DNA fingerprinting vis-a-vis sharīʿah methods for the establishment and negation of paternity, and the reconstructed role and objective of liʿān as a legal method.
In search of a new therapeutic target for the treatment of genetically triggered thoracic aortic aneurysms and cardiovascular conditions: insights from human and animal lathyrism

Lathyrism, or the effect of certain plants on connective tissue disruption, particularly involving the vascular and skeletal systems, especially aortic dissection/rupture, has been well documented in animals. Its impact on the pathogenesis of connective tissue diseases in humans is still unclear. An extensive review of the scientific literature from the 1800s until the present time was performed to examine the common pathways between animal and human lathyrism and genetically triggered thoracic aortic aneurysms and cardiovascular conditions in humans, with special focus on the identification of potential therapeutic targets. Search areas covered the following subjects: lathyrism/spontaneous aortic dissection/rupture in animals; beta-aminopropionitrile, semicarbazide and their effects; collagen and elastin synthesis and cross-linking; genetic and molecular biology characteristics of the genetically triggered thoracic aortic conditions. Search results demonstrate Marfan syndrome as a model for the genetically triggered thoracic aortic aneurysms, has been linked to mutations of the fibrillin-1 gene, via transforming growth factor beta-1. Several other conditions do not share this mutation. Inhibition of semicarbazide-sensitive amine oxidase [vascular adhesion protein-1 (VAP-1)] in animals has been shown to result in aortic dilatation due to disruption of elastin cross-linking. Significantly low activity of this enzyme was identified in annulo-aortic ectasia; a condition similar to Marfan syndrome. In conclusion, the precise molecular and genetic pathways responsible for the clinical findings in Marfan syndrome and related conditions remain unclear. Observational and experimental findings relating to the vascular and systemic effects of molecular pathways implicated in the phenomenon of animal and human lathyrism suggest that VAP-1 seems to be involved in the molecular and developmental pathways of the genetically triggered thoracic aortic diseases and thus could be a potential therapeutic target for these conditions.
Selective area epitaxy of GaAs using tri-isopropylgallium

We have studied the selective area epitaxy of GaAs by chemical beam epitaxy, using tri-isopropylgallium as the Ga source. The results show that GaAs can be selectively grown at a rate of up to ∼0.36 µm/h on patterned GaAs substrates at temperatures as low as 380°C. A low selective growth temperature allows us to utilize deep-ultraviolet radiation to modify the GaAs surface oxides for use as the masking material. We found that excess AsH3 over-pressure degrades the selectivity significantly, and the maximum selective growth thickness is limited by a critical total adatom coverage on the mask. In addition, the low selective growth temperature does not result in a very high C background concentration. Initial Hall measurements indicate that unintentional C doping levels are at least two orders of magnitude lower than those in GaAs layers grown under comparable conditions using trimethylgallium.
Bank debt covenants and firms’ responses to FAS 150 liability recognition: evidence from trust preferred stock

We examine the relation between accounting-based debt contracts and the economic response of firms with trust preferred stock (TPS) to mandated liability recognition under Financial Accounting Standard (FAS) 150. Our results show that firms’ financial covenants significantly affect their choice to redeem versus reclassify their outstanding TPS. Specifically, firms with bank debt covenants that would be adversely impacted by recognizing TPS as a debt liability are 26.88% more likely to redeem their TPS after FAS 150. We also find that firms are significantly more likely to redeem versus reclassify their TPS after FAS 150 if they used the original TPS proceeds to retire existing debt (id est, to enhance their balance sheets). Our findings suggest that when bank debt contracts use “floating” Generally Accepted Accounting Principles (GAAP) to construct financial covenant terms, changes in the underlying GAAP measure significantly influence firms’ economic behavior.
Selectivity among Dehydrogenation Steps for Alkyl Groups on Metal Surfaces: Comparison between Nickel and Platinum†

The thermal chemistry of ethyl and neopentyl iodides on Pt(111) surfaces was investigated by temperature-programmed desorption and reflection-absorption infrared (RAIRS) spectroscopies. The analysis using RAIRS of the isotopic composition of the ethylidyne formed from adsorption of CH 3 CD 2 I at different temperatures provided a reasonable estimate for the difference in activation energies between α- and β-hydride elimination steps from alkyl groups adsorbed on Pt(111). A study of the reactivity of neopentyl groups on the same surface using selective deuterium labeling yielded additional information on the relative rates of α- versus γ-hydride eliminations. It was determined that C-H bond-scission steps at the α and γ positions display comparable rates and that both are several orders of magnitude slower than dehydrogenation at the β carbon. A comparison is also presented here to similar chemistry on nickel substrates, where dehydrogenation reactions are usually much faster and where α-elimination dominates over the γ counterpart. The implications of these results to catalysis are discussed in the text.
Color functions in information perception and retention

Abstract This paper reviews key research findings related to color and how this phenomenon affects the perception and retention of information. From the literature it appears that colors have varying degrees of value as cues or aids to memory of stimulus information and that difference appears to exist between colors as they interact in informational materials.
Gas Pipeline Network Analysis Using an Analytical Steady-State Flow Equation

Zhou and Adewumi proposed an analytical flow equation (ZA model) for steady-state flow through pipelines without neglecting any terms in the momentum equation. In the present study, the linear theory method (LTM) is utilized to solve the network equations based on the ZA model. Some programming strategies are also addressed. A field network with 21 pipes and 16 nodes is simulated using the model, and the simulation results are compared with the field data as well as those obtained using Weymouth equation, Panhandle-A and Panhandle-B equations, respectively.
Laser beacon system for aircraft collision hazard determination.

A laser beacon collision hazard determination system is capable of simultaneously determining range, bearing, and heading of threat aircraft. Calculations demonstrate that threat aircraft may be observed at >10 km under good visibility conditions. When the visibility is limited to 5.6 km (3 nautical miles), the shortest possible warning time for aircraft below 3000 m (10,000 ft) can be >15 sec. A wide variety of detection systems may be chosen based on cost, detection range, and sophistication. Traffic saturation is not a problem since closer aircraft produce easily distinguishable signals so traffic may be prioritized. Preliminary tests demonstrate that accurate range measurements are possible under daylight conditions.
Performance comparison of low current measurement systems for biomedical applications

In this paper, we report on the noise analysis of low current measurement systems for biomedical applications. We analyzed resistive feedback, capacitive feedback and current conveyor circuits for low current measurement systems. Detailed noise analysis are presented and matched with measurement data using a 0.5-µm fabrication process. Based on the theoretical analysis and the measurements, the capacitive feedback system provides better noise performance for the measurement of low current. The capacitive feedback is capable of measuring 700fA RMS at 10KHz sampling rate, whereas the resistive feedback provides 4pA and the current conveyor provides 600pA. This paper provides design guidelines to maximize the measurement performance of low current for biomedical instrumentation.
Calculation of shielding door thicknesses for radiation therapy facilities using the ITS Monte Carlo program.

Shielding calculations for door thicknesses for megavoltage radiotherapy facilities with mazes are generally straightforward. To simplify the calculations, the standard formalism adopts several approximations relating to the average beam path, scattering coefficients, and the mean energy of the spectrum of scattered radiation. To test the accuracy of these calculations, the Monte Carlo program, ITS, was applied to this problem by determining the dose and energy spectrum of the radiation at the door for 4- and 10-MV bremsstrahlung beams incident on a phantom at isocenter. This was performed for mazes, one termed 'standard' and the other a shorter maze where the primary beam is incident on the wall adjacent to the door. The peak of the photon-energy spectrum at the door was found to be the same for both types of maze, independent of primary beam energy, and also, in the case of the conventional maze, of the primary beam orientation. The spectrum was harder for the short maze and for 10 MV vs. 4 MV. The thickness of the lead door for a short maze configuration was 1.5 cm for 10 MV and 1.2 cm for 4 MV vs. approximately less than 1 mm for a conventional maze. For themore » conventional maze, the Monte Carlo calculation predicts the dose at the door to be lower than given by NCRP 49 and NCRP 51 by about a factor of 2 at 4 MV but to be the same at 10 MV. For the short maze, the Monte Carlo predicts the dose to be a factor of 3 lower for 4 MV and about a factor of 1.5 lower for 10 MV. Experimental results support the Monte Carlo findings for the short maze.« less
Theoretical study of the vibration-dependent electron anisotropy in O−2 photodetachment

Recent experimental works report observations of a significant vibrational dependence of the photoelectron angular distributions (PADs) recorded for the O2(X3Σg) ← O−2 (X2Πg) band. It is the aim of the theoretical model presented here to reproduce the experimental results, allow for a deeper insight into the mechanism of this process and explain the sensitivity of the PAD to vibronic coupling in the anion ground electronic state.
Variation of the effective diffusivity in two-phase regions

An equation was derived to calculate the effective diffusivity, [D{sup eff}], in the two-phase region of a ternary alloy. The major assumption made was that the precipitate phase acts like a point source or sink of solute. The equation shows that [D{sup eff}] is constant along a tie line when adjacent tie lines are parallel. Then [D{sup eff}] was calculated at 1200 C in the {gamma} + {beta} region of the Al-Cr-Ni system and plotted as contours on the phase diagram. In order to determine the effect of [D{sup eff}] variation on the modeling, a constant [D{sup eff}] error function prediction of the diffusion path and concentration profiles was compared with a DICTRA finite difference simulation that accounts for diffusivity variations. Although the [D{sup eff}] elements varied between 17 and 51%, the difference between the predictions was negligible.
Mountain West Digital Library

Technical services are at the forefront of the changes that are taking place today in libraries. In this issue, our reviewers will introduce you to useful resources you may not be familiar with that can help you incorporate non-traditional metadata into your cataloging operations, take advantage of social media tools like blogs and crowdsourcing, and gain a better understanding of data-driven assessment.Do you have websites or applications of your own you would like to share with your colleagues in technical services? Our column WELCOMES new reviewers. Send comments and suggestions to the column editor: Marta Mestrovic Deyrup at marta.deyrup@shu.edu
Retarded development of fetal renal alkaline phosphatase in mice given 2,4,5‐trichlorophenoxyacetic acid

Histologic study of the fetal offspring of maternal mice given 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) suggested that the previously reported fetal "cystic kidneys" were due to a retardation in fetal renal development and downgrowth of the renal papilla into the pelvis. To determine a possible retardation in renal alkaline phosphatase or functional development, maternal mice received by gavage 60-120 mg/kg, 2,4,5-T on days 6-14 of pregnancy. At necropsy on day 17, the fetal kidneys were excised and fixed 24 hr in cold 65% ethanol. Paraffin sections stained by Gomori's method revealed alkaline phosphatase mainly in tubules in the inner renal cortex. Fetal kidneys showing diminished or no alkaline phosphatase were designated subnormal. There was a statistically significant greater incidence of subnormal fetal kidneys in the 2,4,5-T-treated mice than in the untreated controls. In three experiments, some mice were also sacrificed on day 18, and the incidence of subnormal fetal kidneys was significantly lower than on day 17. This retardation in renal alkaline phosphatase development indicates a retardation in renal functional development and indirectly supports the view that 2,4,5-T also retards the morphological development of the fetal kidney and is not a renal teratogen in mice. It also illustrates that selected histochemical studies may be helpful in a teratologic investigation.
Structural Stability and Models of the Business Cycle

Ever since the pioneering work of Jan Tinbergen, econometric modelers have been aware of the danger that their models can be unstable over time and across policy environments. Work over the past fifteen years has produced a set of statistical procedures for identifying and modeling structural instability. This essay summarizes some of those procedures, uses them to discuss changes in the U.S. business cycle over the past four decades, and surveys some new research that tackles the widespread challenge of structural instability.
Effect of Strict Glycemic Control in Patients With Diabetes Mellitus on Frequency of Macrovascular Events

Despite a better understanding of cardiovascular risk factors and attempts at optimal management, diabetes-related macrovascular events remain a significant cause of morbidity and mortality in the United States and worldwide. The trials to date have validated strict glycemic control as a method to achieve sustained reductions in the rate of nephropathy, neuropathy, and retinopathy due to diabetes. For these microvascular complications, the closer hemoglobin A1c is to normal levels, the better the outcome. Although reducing hemoglobin A1c levels to 7% has been shown to reduce macrovascular events, demonstrating an additional reduction in macrovascular events with tighter glycemic control has been more difficult to achieve. A careful review of recent trials, however, has demonstrated that treatment early in the disease course and the ability to safely maintain lower hemoglobin A1c levels might be critical factors in further reducing macrovascular events. In conclusion, with the introduction of novel antidiabetic agents, future trials using these drugs might be able to definitively establish the safety and efficacy of reducing cardiovascular events with stringent glycemic control; however, the current evidence is inconsistent.
Structure predictions: The genetics of grain boundaries

The prediction of interface structures is an uncertain and time-consuming task. A technique merging ab initio calculations with a genetic algorithm simplifies the process and provides suitable solutions of the atomic structures that would be hard to envisage a priori.
Fabrication, modeling, and characterization of form-birefringent nanostructures.

A 490-nm-deep nanostructure with a period of 200 nm was fabricated in a GaAs substrate by use of electron-beam lithography and dry-etching techniques. The form birefringence of this microstructure was studied numerically with rigorous coupled-wave analysis and compared with experimental measurements at a wavelength of 920 nm. The numerically predicted phase retardation of 163.3° was found to be in close agreement with the experimentally measured result of 162.5°, thereby verifying the validity of our numerical modeling. The fabricated microstructures show extremely large artificial anisotropy compared with that available in naturally birefringent materials and are useful for numerous polarization optics applications.
Numerical solution of the optimal projection/maximum entropy design equations for low-order, robust controller design

This paper summarizes some recent results obtained using the optimal projection/maximum entropy control-design equations. The main results include: low-order controllers for CSDL Model #2; robust controllers for the SCOLE and VCOSS A models with modal-frequency uncertainties; and Doyles example.
Interactions of the firm's real and financial decisions

This paper provides an integrated approach to the theory of the firm. Under technological uncertainty, corporate taxes, risky debt and risk neutrality it is shown that the firm's investment production and financing decisions are made simultaneously. It is demonstrated that the relationship between optimal capital (or labour) and debt is not strictly negative as in Dotan and Ravid (1982) nor strictly positive as in Hite (1977). The direction of this relationship depends on the characteristics of debt and the characteristics of the firm's production function. Given the simultaneity of the real and financial decisions, it is shown that an interior optimum exists for the firm's value as a function of debt.
Synthesis of carbon‐13 labelled 6‐substituted benzo (a) pyrenes

Sodium formate-13C, prepared by hydrolysis of isopropyl formate, was allowed to react with N-methylaniline hydrochloride to prepare the formylating agent N-methylformanilide-1-13C. Formylation of benzo(a)pyrene with N-methylformanilide-1-13C gave the 6-13CHO derivative which was reduced to 6-13CH3 and 6-13CH2OH benzo(a)pyrenes. 6-13CH2C1 benzo(a)pyrene was prepared from the 6-13CH2OH derivative.
The use of 3-methoxymethyl-16β, 17β-epiestriol-O-cyclic sulfone as the precursor in the synthesis of F-18 16α-fluoroestradiol

Abstract We have prepared 3-methoxymethyl-16β,17β-epiestriol- O -cyclic sulfone (1c) and used it as a substrate for the production of F-18 16α-fluoroestradiol, via nucleophilic fluorination with fluoride ion. The compound is straightforward to make from the commercially available epiestriol and is a stable crystalline compound that can be stored for at least a year at room temperature. Reaction with fluorine-18 fluoride provides excellent yields; typically >90% incorporation of the fluoride is achieved. Partial purification of the labeled product may be accomplished at this stage. Hydrolysis of the methoxymethyl protecting group and ring-opened sulfate occurs rapidly in ethanolic acid solution. In the presence of water the hydrolysis requires more vigorous conditions and additional time but still proceeds to completion. Labeled fluoroestradiol is isolated at the end of a 1–2 h synthesis, depending on the hydrolysis method of 30–45% chemical (decay corrected) yield with respect to fluoride, with a specific activity >1 Ci per micromole.
A molecular orbital study of alkoxy allyl and vinyl anions

The substitution of an alkoxy group for hydrogen is to stabilize by inductive effects both the vinyl and ally1 anions. Since the vinyl carbanion center is more localized, substitution of an OR group adjacent to this center produces a more dominant stabilizing effect than for the ally1 system. Superimposed upon the inductive stabilization is a trend of destabilization of the n system of the ally1 moiety and to a lesser extent the carbanion center of the vinyl anion by the oxygen lone pair orbitals. An interaction diagram for the T orbitals of an ally1 fragment interacting with oxygen lone pair orbitals of the -OR group is shown in Figure 1. The lower molecular orbitals of S and A synzaetry are localized predominantly on the oxygen lone pair orbitals while the high energy orbitals are essentially on the ally1 fragment with some oxygen lone pair character mixed in an antibonding manner. The overall effect is a four-electron destabilizing interaction between the w-donor orbitals on the oxygen with the filled II orbitals of the ally1 moiety. The OR group also has a destabilizing effect in the vinyl anion. In 1 is shown an alkoxy vinyl anion along with optimized values for some of the important structural parameters. The optimized value of 1.45 /! for the C-O bond length in the alkoxy vinyl anion represents an increase
Control of supersonic impinging jet flows using supersonic microjets

Supersonic impinging jets, such as those occurring in the next generation of short takeoff and vertical landing aircraft, generate a highly oscillatory e ow with very high unsteady loads on the nearby aircraft structures and the landing surfaces. These high-pressure and acoustic loads are also accompanied by a dramatic loss in lift during hover.Previousstudies of supersonic impinging jets suggestthatthehighly unsteady behavioroftheimpinging jets is due to a feedback loop between the e uid and acoustic e elds, which leads to these adverse effects. A unique active control technique was attempted with the aim of disrupting the feedback loop, diminishing the e ow unsteadiness, and ultimatelyreducing theadverseeffectsofthise ow.Flowcontrolwasimplementedbyplacingacirculararray of 400-πm-diamsupersonicmicrojetsaroundtheperipheryofthemainjet.Thiscontrolapproachwasverysuccessful in disrupting the feedback loop in that the activation of the microjets led to dramatic reductions in the lift loss (40%), unsteady pressure loads (11 dB), and near-e eld noise (8 dB). This relatively simple and highly effective control technique makes it a suitable candidate for implementation in practical aircraft systems. NUNDERSTANDINGoftheimpingingjete owe eld isnecessary for the design of efe cient short takeoff and vertical landing (STOVL) aircraft. When such STOVL aircraft are operating in hovermode,thatis,in closeproximityto theground,thedownwardpointing lift jets produce high-speed, hot e ow that impinges on the landing surface and generates the direct lift force. It is well known that in this cone guration several e ow-induced effects can emerge, which substantially diminish the performance of the aircraft. In particular, a signie cant lift loss can be induced due to e ow entrainment bytheliftingjetsfromtheambientenvironmentinthe vicinityofthe airframe. Other adverse phenomena include severe ground erosion on the landing surface and hot gas ingestion into the engine inlets. In addition, the impinging e owe eld usually generates signie cantly highernoiselevelsrelativetothatofafreejetoperatingundersimilar conditions. Increased overall sound pressure levels (OASPL) associated with the high-speed impinging jets can pose an environment pollution problem and adversely affect the integrity of structural elements in the vicinity of the nozzle exhaust due to acoustic loading. Moreover, the noise and the highly unsteady pressure e eld are frequently dominated by high-amplitude discrete tones, which may match the resonant frequencies of the aircraft panels, thus further exacerbating the sonic fatigue problem. These problems become more pronounced when the impinging jets are supersonic, the operating regime of the STOVL version of the future joint strike e ghter. In addition, the presence of multiple impinging jets can potentially further aggravate these effects due to the strong coupling between the jets and the emergence of an upward-moving fountain e ow e owing opposite to the lift jets. 1 A