cssi/SciSciGPT-SciSciNet huggingface dataset:
ORIGIN OF HYSTERESIS AND PLATEAU-LIKE BEHAVIOR OF THE I-V CHARACTERISTICS OF RESONANT TUNNELING DIODES

In terms of numerical calculation of the coupled Wigner function–Poisson equations, the explanation to the origin of hysteresis and plateau-like behavior of the I-V characteristics of double barrier resonant tunneling devices is put forth. Several basic physical factors play key roles in the process of electron tunneling. Among these the most important factors are the interference of the injected and the reflected electron waves which leads to the formation of an emitter quantum well, the coupling between the energy level in the main quantum well and that in the emitter quantum well, and the coupling between the energy level in the main quantum well and the conduction b and edge or the three-dimensional states in the emitter. The interplay of these factors determines the form of the I-V curve of the resonant tunneling structure. The coupling between the energy levels in the emitter quantum-well and the main quantum-well leads to the plateau behavior of the I-V curves. The strength of the coupling determines the average slope of the plateau-like region in the I-V curve. The bias domain that the coupling exists determines the length of the plateau-like structure in the I-V curve. The domain can be controlled by adjusting the width of the barriers. The hysteresis is shown to be a manifestation of the above-mentioned energy level coupling, the coupling between the energy level in the main quantum well and the conduction b and edge or the three-dimensional states in the emitter, and the quantitative accumulation and distribution of electrons in the emitter region. This work provides new insight for underst and ing the nonlinear I-V behavior and establishes a foundation for the future analysis of bistability and oscillation behavior in resonant tunneling structures.
High performance steel bridge girder compactness

Abstract The present study employs experimentally verified nonlinear finite element modeling techniques for the study of high performance steel (HPS) I-shaped bridge girders. An evaluation as to the appropriateness of using the current American bridge specification (AASHTO 1998) provisions for cross-sectional compactness and adequate bracing is carried out within the context of applications involving A709 Gr. HPS483W high performance steel. It appears that the current AASHTO bracing provisions are inadequate when applied to A709 Gr. HPS483W bridge girders; intense interactions between local and global buckling manifestations occur in the HPS bridge girders studied herein despite satisfaction of the AASHTO requirements. As a result of the interaction between local and global instabilities, the application of the separately defined AASHTO cross-sectional compactness criteria becomes invalid. An alternate bracing requirement is proposed for use with HPS bridge girders as part of this research. This new bracing scenario does not require any additional costs in fabrication or materials since only the placement of the required bracing is changed with respect to current practice and not the total number of braces. Once the new bracing scenario is implemented, the notion of cross-section compactness once again has validity and thus correlates with HPS I-shaped girder flexural ductility. New flange and web compactness criteria are proposed for use with A709 Gr. HPS483W bridge girders braced in the manner specified herein.
Species-Specific Exon Loss in Human Transcriptomes

Changes in exon-intron structures and splicing patterns represent an important mechanism for the evolution of gene functions and species-specific regulatory networks. Although exon creation is widespread during primate and human evolution and has been studied extensively, much less is known about the scope and potential impact of human-specific exon loss events. Historically, transcriptome data and exon annotations are significantly biased toward humans over nonhuman primates. This ascertainment bias makes it challenging to discover human-specific exon loss events. We carried out a transcriptome-wide search of human-specific exon loss events, by taking advantage of RNA sequencing (RNA-seq) as a powerful and unbiased tool for exon discovery and annotation. Using RNA-seq data of humans, chimpanzees, and other primates, we reconstructed and compared transcript structures across the primate phylogeny. We discovered 33 candidate human-specific exon loss events, among which six exons passed stringent experimental filters for the complete loss of splicing activities in diverse human tissues. These events may result from human-specific deletion of genomic DNA, or small-scale sequence changes that inactivated splicing signals. The impact of human-specific exon loss events is predominantly regulatory. Three of the six events occurred in the 5' untranslated region (5'-UTR) and affected cis-regulatory elements of mRNA translation. In SLC7A6, a gene encoding an amino acid transporter, luciferase reporter assays suggested that both a human-specific exon loss event and an independent human-specific single nucleotide substitution in the 5'-UTR increased mRNA translational efficiency. Our study provides novel insights into the molecular mechanisms and evolutionary consequences of exon loss during human evolution.
Functional symmetry of UhpT, the sugar phosphate transporter of Escherichia coli.

UhpT, the sugar phosphate transporter ofEscherichia coli, acts to exchange internal inorganic phosphate for external hexose 6-phosphate. Because of this operational asymmetry, we studied variants in which right-side-out (RSO) or inside-out (ISO) orientations could be analyzed independently to ask whether the inward- and outward-facing UhpT surfaces have different substrate specificities. To study the RSO orientation, we constructed a histidine-tagged derivative, His10K291C/K294N, in which the sole external tryptic cleavage site (Lys294) had been removed. Functional assay as well as immunoblot analysis showed that trypsin treatment of proteoliposomes containing His10K291C/K294N led to loss of about 50% of the original population, reflecting retention of only the RSO population. To study the ISO orientation, we used a His10V284C derivative, in which a newly inserted external cysteine (Cys284) conferred sensitivity to the thiol-reactive agent, 3-(N-maleimidylpropionyl)biocytin. In this case, 3-(N-maleimidylpropionyl)biocytin treatment of proteoliposomes containing His10V284C gave about a 60% loss of activity, and immunodetection of biotin showed parallel modification of an equivalent fraction of the original population. Together, such findings indicate that the UhpT RSO and ISO orientations are in about equal proportion in proteoliposomes and that a single population can be generated by exposure of these derivatives to the appropriate agent. This allowed us to study proteoliposomes with UhpT functioning in RSO orientation (His10K291C/K294N) or ISO orientation (His10V284C) with respect to the kinetics of glucose 6-phosphate transport by phosphate-loaded proteoliposomes and also the inhibitions found with 2-deoxy-glucose 6-phosphate, mannose 6-phosphate, galactose 6-phosphate, fructose 6-phosphate, and inorganic phosphate. We found no significant differences in the behavior of UhpT in its different orientations, indicating that the transporter possesses an overall functional symmetry.
Essentials of the Disclosure Review Process: A Federal Perspective

MANY RESEARCHERS NEED TO MAKE arrangements to share de-identified electronic data files. However, the ways in which respondent identity may be protected are not well understood or are assumed to be the special province of large statistical agencies or specialized statisticians. Approaches to data sharing and protecting respondent identity have been pioneered by federal agencies which gather data vital to political and economic decision making. These agencies are required by statutory law both to assure confidentiality and to share data in usable form with other governmental agencies and with scholars who perform needed analyses of those data. The basic principles of disclosure limitation developed by the Census Bureau, the National Center for Health Statistics, and other federal agencies are fundamental to meeting new funding requirements to share and deidentify data, and are often referred to in the literature on data sharing. We describe how these principles are employed by the Disclosure Review Boards (DRBs) of these two agencies, and then state these principles in more general terms that are applicable to any disclosure review process. The kinds of data that academic institutions share may call for less complex or stringent DRBs and specific nondisclosure procedures different from those employed by federal agencies, but the same general principles apply. Specific application of these six principles by non-government researchers will depend on the nature of their data, their own institutional resources, and the likely future usefulness of their data.
A method for determining the asperity distribution of contacting rough surfaces

The Greenwood and Williamson (1966) model is an elegant and often-cited paradigm for predicting the load-displacement behavior of contacting rough surfaces given the height distribution of the contacting asperities. By use of an inverse technique and available load-displacement data, this work provides an alternative method to determine the asperity distribution directly from topographic measurement and subsequent data reduction. This method produces distributions that are consistent with the Greenwood and Williamson representation of the load-displacement data and demonstrates how the asperity height distribution can evolve with loading.
Crossed and uncrossed projections to the cat sacrocaudal spinal cord: III. Axons expressing calcitonin gene-related peptide immunoreactivity.

We have investigated the projection patterns of peptidergic small-diameter primary afferent fibers to the cat sacrocaudal spinal cord, a region associated with midline structures of the lower urogenital system and of the tail. Calcitonin gene-related peptide (CGRP)-immunoreactive (CGRP-IR) primary afferent fibers were observed within the superficial laminae, rostrally as the typical inverted U-shaped band that capped the separate dorsal horns (S1 to rostral S2) and caudally as a broad band that spanned the entire mediolateral extent of the fused dorsal horns (caudal S2 and caudal). Within the dorsal gray commissure, labeling was seen as a periodic vertical, midline band. CGRP-IR labeling was prevalent in an extensive mediolateral distribution at the base of the dorsal horn, originating from both lateral and medial collateral bundles that extend from the superficial dorsal horn. Some bundles, in part traveling within the dorsal commissure, conspicuously crossed the midline. In addition to the robust projection to the superficial dorsal horn, there was a more extensive distribution of CGRP-IR fibers within the deeper portions of the cat sacrocaudal dorsal horn than has been reported for other regions of the cat spinal cord. Presumably, these deep projections convey visceral information to projection or segmental neurons at the neck of the dorsal horn and in the region of the central canal. This deep distribution overlaps the reported projections of the pelvic and pudendal nerves. In addition, the contralateral projections of CGRP-IR fibers may form an anatomical substrate of the bilateral receptive fields for selective dorsal horn neurons. The density and variety of CGRP-IR projection patterns is a reflection of the functional attributes of the innervated structures. J. Comp Neurol. 438:388–398, 2001. © 2001 Wiley-Liss, Inc.
Quantitative relativizations of complexity classes

Consider the following open problems: (i) ${\text{P}} = ? {\text{ NP}}$ (ii) ${\text{NP}} = ? {\text{ co-NP}}$; (iii) ${\text{P}} = ? {\text{ PSPACE}}$; (iv) ${\text{NP}} = ? {\text{ PSPACE}}$. In this paper we study these four problems from a particular point of view. To illustrate our approach, consider the first problem. It is known that there exist recursive sets A and B such that ${\text{P}}(A) = {\text{NP}}(A)$ and ${\text{P}}(B) \ne {\text{NP}}(B)$. We study restrictions R on both the deterministic and also the nondeterministic polynomial time-bounded oracle machines such that the following holds: ${\text{P}} = {\text{NP}}$ if and only if for every set A, ${\text{P}}_R (A) = {\text{NP}}_R (A)$. The restrictions are “quantitative” in the sense that the size of the set of strings queried by the oracle in computations of a machine on an input is bounded by a polynomial in the length of the input. We study several different ways of specifying such quantitative restrictions, each of which has the desire...
Future of governance workshop summary

Abstract This paper presents the results of a workshop on the future of governance held at the University of Tennessee, Knoxville. The participants were broken into five groups based on different perspectives on governance: local, state, federal, international, and courts. Each group developed a definition of good governance, assessed trends impacting their conception of good governance, developed future scenarios, and tested the scenarios against six wildcards. Good governance is characterized by transparency, accountability, representativeness, and effectiveness. Unfortunately, most trends are negatively impacting good governance, with advanced in information technology being the lone exception. World governments face a catch-22 situation because in order to deal with these negative trends they need to improve in all aspects.
Asthma, Genes, and Air Pollution

Objective:The objective of this article is to evaluate genetic risks associated with the pulmonary response to air pollutants, including particulates and ozone.Methods:A comprehensive review of articles related to the genetics of asthma with particular attention to air pollution was conducted throug
Constructing endotrivial modules

Abstract A classification of endotrivial modules over p -groups was recently completed by the author and Jacques Thevenaz relying on generators for the group of endotrivial modules created by Alperin, Dade and others. In this paper we present a completely new construction of a set of generators using methods of group cohomology, some of which were developed in the classification. The new method has the advantage that all endotrivial modules can be constructed by the homological technique. In addition, the method applies to endotrivial modules over groups that are not p -groups.
The University of California at San Diego Near-Infrared Charge-Coupled Device (CCD)

We discuss a newly operational CCD imaging system optimized for the near infrared. The CCD is a front-side illuminated, three-phase, 385 x 578 GEC chip. The system is run by an LSI-11/23 computer with a FORTH language operating system. Hardware control signals are sent via a CAMAC interface. The important parameters characterizing the CCD are discussed. Finally, we describe some recent broadband observations of the interacting galaxies Markarian 171 made with the Mt. Lemmon Observatory 1.5 meter telescope.
A Randomized Controlled Trial of Intraarticular Ropivacaine for Pain Management Immediately Following Total Knee Arthroplasty

Total knee arthroplasty (TKA) is a commonly performed procedure for the treatment of end-stage arthritis of the knee. Pain control following TKA is difficult to manage in some patients. We examined the use of a postoperative intraarticular injection of 100 mL of 0.2% (200 mg) ropivacaine in a double-blind, prospective, placebo-controlled pilot study to evaluate its use as a pain control modality. All patients received general anesthesia. Postoperatively, patients were placed on intravenous patient-controlled analgesia with morphine. The ropivacaine group showed an early trend in lower visual analog scale (VAS) scores when compared with the placebo group. Patients receiving ropivacaine used a similar amount of narcotics compared with the placebo group. Intraarticular ropivacaine used for pain control after TKA demonstrated no statistically significant difference in lowering VAS scores or narcotic usage; therefore, intraarticular ropivacaine as a single modality is not recommended for effective pain management.
Relation of mitral valve prolapse to left ventricular size in Marfan's syndrome

Abstract Sporadic recent reports suggest that mitral valve prolapse (MVP) disappears with progressive left ventricular (LV) dilatation. To test this hypothesis, we sought to determine if an inverse relation exists between MVP and LV cavity size on M-mode echocardiograms in 83 patients with Marfan's syndrome. LV end-diastolic dimensions and presence or absence of MVP were determined. Forty-six patients had MVP. Of patients with an LV end-diastolic dimension ≤ 5 cm, 90% had MVP; only 19% of the 32 patients with abnormally large (>5.8 cm) end-diastolic dimension had MVP. The prevalence of MVP in patients with an LV end-diastolic dimension of 5.1 to 5.8 cm was 69%. Thus, the prevalence of MVP was inversely related to LV cavity size. To determine whether appearance or disappearance of MVP was associated with decrease or increase in LV cavity size, serial echocardiograms from 67 patients (mean follow-up 42 months, range 3 to 99) were examined. These patients were separated into 3 groups based on changes in the LV end-diastolic dimension of >1 cm over time. Group 1 consisted of 9 patients, all of whom had MVP and normal LV cavity size on their initial study. With subsequent increase in LV end-diastolic dimension (mean 1.42 ± 0.3), MVP disappeared in 6 of the 9. Conversely, group 2 consisted of 4 patients, all of whom had dilated left ventricles on their initial echocardiogram and no evidence of MVP. After aortic valve replacement, the LV cavity size decreased (mean 2.3 ± 0.7) and MVP appeared on follow-up studies. Group 3 consisted of 54 patients with little or no change in LV end-diastolic dimension (≤ 1 cm, mean 0.4 ± 0.2 cm). In this group, MVP status remained unchanged throughout the follow-up period. Thus, in patients with Marfan's syndrome, serial increase or decrease in LV size is associated, respectively, with disappearance or appearance of MVP.
Efficient algorithm for simulating homogeneous turbulent shear flow without remeshing

The Rogallo (1981) algorithm for simulating homogeneous turbulent shear flow solves the equations on a mesh that in physical space deforms with the mean flow. Eventually, when the mesh reaches a particular degree of deformation, the coordinate system must be ''remeshed''. Remeshing introduces unavoidable numerical errors such as loss of turbulent kinetic energy and dissipation rate and is therefore not desirable. In this paper, we present a new algorithm for simulating homogeneous turbulent shear flow, based on a Fourier decomposition of the velocity field, that avoids the troublesome remeshing step. Equations for the Fourier amplitudes of three components of velocity are advanced in time; however, nonlinear terms are calculated on a stationary, orthogonal mesh in physical space, allowing traditional de-aliasing procedures to be used. The resulting spectral transforms involve a phase shift to account for the frame of reference change; consequently, the standard three-dimensional fast Fourier transforms (3D FFT) cannot be used. We have developed an algorithm that accomplishes the spectral transforms at a computational cost that still scales like O(N^3lnN) operations, where N is the number of grid points in each direction. A fully parallel version of the algorithm has been implemented to run on 2^p processors, where p is a positive integer. Results over a broad range of the shear parameter, S^*, demonstrate the advantages of avoiding the remeshing step.
THE CODE THEORY OF VISUAL ATTENTION : AN INTEGRATION OF SPACE-BASED AND OBJECT-BASED ATTENTION

This article presents a theory that integrates space-based and object-based approaches to visual attention. The theory puts together M.P. van Oeffelen and P.G. Vos's (1982, 1983) COntour DEtector (CODE) theory of perceptual grouping by proximity with C. Bundesen's (1990) theory of visual attention (TVA). CODE provides input to TVA, accounting for spatially based between-object selection, and TVA converts the input to output, accounting for feature- and category-based within-object selection. CODE clusters nearby items into perceptual groups that are both perceptual objects and regions of space, thereby integrating object-based and space-based approaches to attention. The combined theory provides a quantitative account of the effects of grouping by proximity and distance between items on reaction time and accuracy data in 7 empirical situations that shaped the current literature on visual spatial attention.
Perioperative closure-related complication rates and cost analysis of barbed suture for closure in TKA.

Background The use of barbed suture for surgical closure has been associated with lower operative times, equivalent wound complication rate, and comparable cosmesis scores in the plastic surgery literature. Similar studies would help determine whether this technology is associated with low complication rates and reduced operating times for orthopaedic closures.
WE‐A‐201C‐01: Current US QC Recommendations and Techniques

Ultrasound is a widely dispersed imaging modality in the current health‐care environment, encompassing various specialties such as radiology, cardiology, ob/gyn, vascular surgery, and emergency medicine. Reasons for this widespread use include: a) relatively low‐cost, b) small, portable machines and c) the non‐invasiveness of the procedure and general perception of minimal risk. All three reasons present challenges to the medical physicist tasked with implementing a quality control program. Nevertheless, the rationale for establishing a standard‐of‐care is important enough to overcome these perceptions. The ongoing and rapid evolution of US technology brings more complexity to these instruments; thus, quality control tests for US can provide benchmarks of performance that are increasingly important to government and private entities that reimburse for health care services. This course will review the steps necessary to start an ultrasoundquality control program, including a review of the appropriate tests and test objects (phantoms) that a part of such a program. The course will address the more critical aspects of ultrasound system performance that affect image quality. In addition, each test will be described in light of standards established by organizations with an interest in ultrasoundquality control. In many cases, these organizations operate some accreditation program for ultrasound imaging facilities. These programs will be reviewed with respect to requirements for a medical physicists contribution to the success of an accreditation application. Learning Objectives: 1. Understand the beginning steps to implement a Quality Control program for ultrasound equipment 2. Know which tests are appropriate to assessing clinical image quality. 3. Know selection of test objects appropriate for these tests. 4. Knowing how to establish objective criteria and, 5. a basic introduction to accreditation bodies and standards for ultrasound QC.
Light Bait Improves Capture Success of Aquatic Funnel-Trap Sampling for Larval Amphibians

Abstract Aquatic funnel traps are a non-destructive means of surveying amphibians in lentic habitats, particularly as compared to dip-net surveys that disturb aquatic vegetation and the substrate, and affect the water column through increased turbidity. The objective of this study was to examine the utility of glow stick-baited aquatic funnel traps for larval amphibians, with a particular emphasis on ambystomatid larvae. We sampled 12 isolated ponds in the Mid-Atlantic Coastal Plain of South Carolina between April and June 2010 and used detection/non-detection capture data to model the probability of capturing larval amphibians in baited and un-baited funnel traps. Further, we used count data (captures per trap) to examine whether glow stick-baited traps captured more amphibian larvae than un-baited traps. We captured four Ambystoma species (A. mabeei, A. opacum, A. talpoideum, and A. tigrinum) and tadpoles from the families Bufonidae, Ranidae, and Hylidae in light-baited funnel traps. Captures of both Am...
The Weyl-Cartan theorem and the naturalness of general relativity

Cartan proved an important theorem showing that Einstein's general relativity is essentially the only theory of gravity that involves the metric tensor, its first derivatives, and linear functions of its second derivatives. Weyl gave a simplified, less general version of this theorem, which we explain in detail. Both emphasize the centrality of the curvature scalar and the naturalness of general relativity.
Thiazolidinedione use and risk of hospitalization for pneumonia in type 2 diabetes: population based matched case-control study

Objective: Previous randomized clinical trials and their meta-analyses have raised the possibility that thiazolidinediones (rosiglitazone and pioglitazone) may increase the risk of pneumonia. We aimed to test the hypothesis that thiazolidinediones may increase the risk of pneumonia. Design: Population based case-control study using a new user design. Setting: A large administrative database in the United States from 2002 to 2008. Population : Adults with type 2 diabetes aged 18-64; restricted to 6129 hospitalized pneumonia cases and 6129 controls without congestive heart failure matched on age, sex, enrollment pattern and diabetes complication severity index matched controls. Conditional logistic regression was used to analyse the data. Results : Compared with controls, cases were more likely to have chronic obstructive pulmonary disease (COPD), tobacco use, cancer and have received influenza and pneumococcal vaccination. After adjusting for COPD, cancer, tobacco use, and receipt of influenza and pneumococcal vaccination, and exposure in other periods, neither recent exposure to pioglitazone (adjusted Odds Ratio [aOR], 1.15, 95% Confidence intervals 1.00 – 1.32) or rosiglitazone (aOR 1.09, 95% CI, 0.83 – 1.44) nor current exposure to pioglitazone within 60 days (aOR, 1.04, 95% CI, 0.60 – 1.79) was associated with a statistically significant odds of pneumonia. Current exposure to rosiglitazone was associated with a statistically significant reduction in the odds of pneumonia (aOR, 0.33, 95% CI 0.11-0.95). Conclusion : In this study of US adults with type 2 diabetes we did not detect a significant increased risk of pneumonia with the thiazolidinediones. The unusually large protective effect of current exposure to rosiglitazone reflects the healthy user effect or unmeasured confounding.
I-V Characteristics and Interface Properties of Al-Si(P) Contacts by the Krf Excimer Laser Induced Recrystallization

Al was deposited on the both sides of p-type Si by the sputtering, and the pulsed KrF excimer laser was irradiated on the one side and both sides of Al dot contacts. Due to the thin-high doping recrystallized layer, the transitions from the Schottky diodes to the ohmic contacts via backward diodes were observed in I-V measurement. Good N-shape negative resistances and notches were observed in the diodes, and ohmic contacts. Possible interpretations of the orgin of these phenomena are discussed. And, the simple model of the effective barrier height reduction under the thermionic field emission was developed using WKB approximation, and tunneling theory. By the depth Auger analysis, Al, and Si profiles near Al-Si interface after the laser irradiation were observed.
Risk measures in strategic management research: auld lang syne?

Risk is an integral component of strategic management decisions and often appears as an element of empirical studies reported in the strategic management literature. Recent methodological research in the financial economics and management science literatures has, however, raised serious questions about the strategic management literature’s two most widely used measures of firm and business-level risk: beta (or its derivatives) from the Capital Asset Pricing Model and simple variance (or its variants). This research reviews risk studies published in leading management journals in the past 15 years and summarizes the recent methodological findings in the adjacent literatures. We discuss the implications of these findings for our understanding of risk in strategic management and assess alternative measures of risk and conclude with a discussion of directions for future strategy research. Copyright © 1999 John Wiley & Sons, Ltd.
Global Perspectives on Information, Communication, and E-Commerce

Robert O. Briggs is the Director of Academic Affairs for the Institute for Collaboration Science and Professor of Marketing and Management at the University of Nebraska. He is also an Associate Professor of Systems Engineering at the Delft University of Technology in the Netherlands. He earned his Ph.D. in Management and Information Systems from the University of Arizona in 1994. He researches the theoretical foundations of collaboration and applies his findings to the design and deployment of new collaboration technologies and work practices. He is a codeveloper of the Collaboration Engineering discipline, and co-inventor of the ThinkLets design pattern language for collaboration processes.
Stueckelberg Z ' extension with kinetic mixing and millicharged dark matter from the hidden sector

An analysis is given of the Stueckelberg extension of the standard model with a hidden sector gauge group U(1){sub X} where the mass growth for the extra gauge boson occurs via the Stueckelberg mechanism, and where the kinetic mixing in the U(1){sub X}xU(1){sub Y} sector is included. Such a kinetic mixing is generic in a broad class of supergravity and string models. We carry out a detailed global fit of the model with the precision CERN LEP data on and off the Z pole, with {chi}{sup 2} within 1% of the {chi}{sup 2} of the standard model fit. Further, it is shown that, in the absence of matter in the hidden sector, there is a single effective parameter that controls the deviations from the standard model predictions, and the dependence on the kinetic mixing emerges only when matter in the hidden sector is included. An analysis is also given of millicharged dark matter arising from the hidden sector, where it is shown that such dark matter from the Stueckelberg extension can satisfy WMAP-3 data while allowing for a sharp Z{sup '} resonance which can be detected at the Tevatron and at the CERN LHC via a dilepton signal generated bymore » the Drell-Yan process.« less
Comments on "A Fast Algorithm for the estimation of autocorrelation functions"

A recently published algorithm for the estimation of arithmetic autocorrelation functions may be further refined. The premultiplications may be converted into simple additions which are efficiently computed within the algorithm. Savings in storage and computational effort are realized.
Scale-invariance in reaction-diffusion models of spatial pattern formation

We propose a reaction-diffusion model of spatial pattern formation whose solutions can exhibit scale-invariance over any desired range for suitable choices of parameters in the model. The model does not invoke preset polarity or any other ad hoc distinction between cells and provides a solution to the French flag problem without sources at the boundary. Furthermore, patterns other than the polar pattern that usually arises first in a growing one-dimensional system described by Turing's model can be obtained. Evidence is given that suggests that the model may apply in the slug stage of Dictyostelium discoideum.
Smooth toral actions

INTRODUCTION A p-torus is a product of cyclic groups of order p if p is an odd prime, and a product of circles if p is zero. In this paper we are concerned with the smooth action of a p-torus A on a differentiable manifold M. There is a classifying bundle EA + BA; let MA = EAx,M be the orbit space of the diagonal action of A on EAxM. The Bore1 equivariant cohomology ring of the A-space M is defined by the formula
Neuroticism and post-traumatic stress disorder: a prospective investigation

Background Neuroticism has been consistently correlated with the post-traumatic stress disorder (PTSD) response to traumatic events. Interpretation of these findings is limited by the retrospective nature of these findings: neuroticism was measured after the trauma had occurred. The prospective association of neuroticism with PTSD has not been examined (the relationship of neuroticism with PTSD symptoms was examined in a few prospective studies). We evaluate prospectively the relationship of neuroticism, measured at baseline, with the cumulative occurrence of PTSD during the subsequent 10 years, using data from a longitudinal epidemiological study of young adults. Method A sample of 1007 young adults randomly selected from the membership of a large health maintenance organization in southeast Michigan was assessed at baseline and followed up at 3, 5 and 10 years later. We conducted a series of multinomial logistic regressions to estimate the relative risk (RR) of exposure to trauma and PTSD by neuroticism at baseline, adjusting for history of major depression (n = 990). Results During the 10-year follow-up, 50.2% of the sample experienced traumatic events and 5.2% developed PTSD. Neuroticism score at baseline increased significantly the RR of PTSD response to trauma. Additional analysis revealed that, among persons with history of major depression at baseline, RR for PTSD associated with neuroticism was equal to the null value of 1, but was increased significantly among those with no history of major depression. Conclusions The results confirm the role of neuroticism as diathesis in the PTSD response to traumatic experiences.
N-terminal acetylation targets GTPases to membranes.

The small GTPases Arl3p and Arl1p function sequentially to recruit diverse effector proteins to the Golgi apparatus. Similarly to ARF proteins, Arl1p is targeted to membranes by myristoylation. Arl3p, however, is not myristoylated. Recent work demonstrates that Arl3p, and its mammalian orthologue ARFRP1, are targeted to membranes by amino-terminal acetylation, which facilitates recognition by the membrane receptor Sys1p/hSys1.
Long-term sampling of intraventricular CSF in the unanesthetized monkey and dog.

Recent investigations in our laboratory concerning the etiology and pathophysiology of hepatic encephalopathy have necessitated repeated reproducible access to the ventricular cerebrospinal fluid in monkeys and dogs [2, 4, 51. Initially, CSF was obtained by repeated cisternal puncture. Since any movement by the animal during puncture could be fatal, CSF was collected under anesthesia, which might possibly alter the neurochemical transmitter content. Moreover, CSF of cisternal or lumbar origin is not representative of ventricular CSF. As most of the available techniques for collecting ventricular or cisternal CSF do not provide enough volume for detailed analysis [ 1, 3, 71, development of cannulation techniques for serial sampling of ventricular CSF without anesthesia in amounts of 810 ml/day became necessary. Two years of experience using these techniques have demonstrated their simplicity, reproducibility, and safety.
Quantification of antibiotic in biofilm-inhibiting multilayers by 7.87 eV laser desorption postionization MS imaging.

The potential of laser desorption postionization mass spectrometry (LDPI-MS) imaging for small molecule quantification is demonstrated here. The N-methylpiperazine acetamide (MPA) of ampicillin was adsorbed into polyelectrolyte multilayer surface coatings composed of chitosan and alginate, both high molecular weight biopolymers. These MPA-ampicillin spiked multilayers were then shown to inhibit the growth of Enterococcus faecalis biofilms that play a role in early stage infection of implanted medical devices. Finally, LDPI-MS imaging using 7.87 eV single-photon ionization was found to detect MPA-ampicillin within the multilayers before and after biofilm growth with limits of quantification and detection of 0.6 and 0.3 nmol, respectively. The capabilities of LDPI-MS imaging for small molecule quantification are compared to those of MALDI-MS. Furthermore, these results indicate that 7.87 eV LDPI-MS imaging should be applicable to quantification of a range of small molecular species on a variety of complex o...
Male size, spawning pit size and female mate choice in a lekking cichlid fish

Abstract In the lekking cichlid fish, Oreochromis mossambicus , males dig and defend spawning pits where courtship and mating occur. Under natural conditions, females may encounter solitary or aggregated males and experience varying degrees of male interference during courtship and spawning Female mating preferences are difficult to tease apart from the effects of male-male competition in these circumstances. Mate choice by females was studied in the laboratory under conditions that prevented male-male competition and courtship interference. Female O. mossambicus received choices between (1) a large and a small male or (2) a large and a small spawning pit. Females showed no preference based on male size, but 17 of 19 females chose the larger spawning pit. To determine the relationship between male size and spawning pit size, the volumes of spawning pits dug by small and large males in wading pools were measured. Spawning pit sizes of small and large males were similar regardless of whether small and large males were segregated or inter-mixed. Therefore, male size was not a good predictor of spawning pit size. To determine whether interactions between males influence female mate choice, females were presented with an interacting pair of males. Seventeen of 19 females mated with the larger of the two males. Videotape analysis revealed that large and small males were similar in behaviour during two of the three time blocks analysed. Although male behaviour may have influenced female decisions, male size was the most salient feature. The results confirm that females assess both site and male characteristics, and suggest that female choice and male-male competition together are important components of sexual selection in this lekking animal.
Covalent Dimerization of Recombinant Human Interferon-γ

Abstract An apparently nonreducible covalent dirner has been consistently observed as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). These studies endeavor to understand the nature of this covalent dimerization. Amino acid sequence analysis of a recombinant human interferon-γ stored for 2 years showed a major sequence starting with the intact N-terminal methionine and a minor sequence corresponding to the C-terminal seven amino acids of the intact protein. Moreover, when the same material was analyzed by gel filtration in the presence of 8 M urea, a minor peak corresponding to the dimer was observed prior to the monomer peak. Reducing and nonreducing SDS-PAGE also showed a minor band corresponding to a dimer. These results suggest that the reactions of C-terminal processing and dimerization have occurred during storage. Reverse-phase chromatography of stored, unfractionated material showed three peaks. Mass spectral analysis of the first, second, and third peaks gave molecular weights of 16,900, 16,100, and 33,000. Since no major cleavage was observed in the N-terminal region of the protein, the observed masses suggest that the first peak corresponds to residues 1 to 144 (a full-length molecule), the second peak to residues 1 to 137 (des 7 interferon-γ), and the third peak to a dimer. Calculation of theoretical molecular weight from the amino acid sequence suggests that this dimer corresponds to some combination of the intact protein and des 7 protein. Tryptic peptide maps in conjunction with sequence and mass analyses identified a new tryptic peptide in the map of the dimer corresponding to residue 133 to 137 followed by residues 1 to 7. The conclusion is recombinant methionyl human interferon-γ undergoes a specific cleavage at the C-terminal side of residue 137 phenylalanine, and a conventional peptide bond was formed between residues 137 and 1 methionine.
Uniaxial stress dependence of the fermi surface of zinc

The effect of uniaxial stress on the areas of several orbits of the zinc Fermi surface have been studied by measuring the phase shifts of the magnetoacoustic quantum oscillations of ultrasonic attenuation. The orbits studied were the two third-zone electron orbits, i.e., the lens (ζ) and the needles (α), and four hole orbits on the second-zone monster, i.e., two horizontal arm orbits (s), with the magnetic field, H, along 〈1120〉 and 〈1010〉, and two junction orbits (Γ), with H along 〈1120〉, and the bow-tie orbit (σ) with H along 〈1010〉. Calculations of the stress dependence were carried out on the basis of a non-local pseudopotential model for the zinc Fermi surface and compared with the experimental results obtained. Good numerical agreement was thus obtained in half of the cases studied. Discrepancies of about a factor of two were found in the other cases, while the largest and smallest values of the stress derivatives (both measured and calculated) differed by as much as a factor of 100. Der Einflus einachsiger Spannung auf die Flachen verschiedener Bahnen der Fermiflachen von Zink wurden durch Messung der Phasenverschiebungen der magneto-akustischen Quantenoszillationen der Ultraschalldampfung untersucht. Die untersuchten Bahnen waren die beiden Elektronenbahnen der dritten Zone, d. h. die Linse (ζ) und die Nadeln (α) und vier Locherbahnen auf dem Monster der zweiten Zone, d. h. zwei Bahnen des horizontalen Arms (s) mit Magnetfeld H in Richtung 〈1120〉 and 〈1010〉, zwei Verbundbahnen (σSG) mit H in Richtung 〈1120〉 und die Schleifenbahn (Γ) mit Hfin Richtung 〈1010〉. Die Rechmmg der Spannungsabhangigkeit wurde auf der Grundlage eines nicht-lokalen Pseudopotential-modells fur die Zink-Fermiflache durchgefuhrt und mit erhaltenen experimentellen Werten verglichen. In der Halfte der untersuchten Falle wurde gute numerische Ubereinstimmung erhalten. Diskrepanzen bis zu einem Faktor zwei wurden in den anderen Fallen gefunden, wahrend die grosten und kleinsten Werte der Spannungskoeffizienten (sowohl gemessen als auch berechnet) sich um mehr als den Faktor 100 unterschieden.
Substance dependence, family history of alcohol dependence and neuropsychological functioning in adolescence.

Aims. It was hypothesized that adolescent substance dependence moderates the relationship between family history of alcohol dependence and neuropsychological functioning. Design. This study compared the neuropsychological functioning of nonabusing and alcohol and drug-dependent adolescents with and without a family history of alcohol dependence using hierarchical multiple regressions and general factorial analyses. Setting. Substance-dependent adolescents were recruited and tested in inpatient alcohol and drug abuse treatment programs after 3 weeks of abstinence. A matched sample of non-abusing adolescents was recruited from the same San Diego-area communities. Participants. Substance-dependent adolescents (n = 101) met DSM-III-R criteria for dependence on alcohol and at least one other substance. Non-abusing adolescents (n = 50) had no substance use disorders. Groups were comparable on socio-economic status. Participants were 44% female, ages 13-18, and had no serious head injuries or neurological disorders. Measurements. Information was gathered on demographics, family history, substance involvement, and conduct disorder behaviors and adolescents were administered neuropsychological tests covering language, visuospatial, verbal memory, attention and executive functioning domains. Findings. The hypothesis was supported for language and attention tests. Substance involvement interacted with family history of alcohol dependence to predict language and attention functioning. Family history negative non-abusers performed better than the other adolescents. Conclusions. The pattern of results suggests that family history of alcohol dependence and adolescent substance use are separate risk factors for poorer neuropsychological performance in youth.
Utility of Contrast Echocardiography in the Diagnosis of Aortic Dissection

Determination of ascending aortic involvement in aortic dissection has significant implications in prognosis, immediate surgical referral, and surgical approach. We report 2 cases of the use of an echo contrast agent in enhancing the diagnostic capability of transesophageal echocardiography in suspected ascending aortic dissection. Contrast echocardiography eliminated the linear artifacts often confused with true dissection flaps and allowed easy identification of the presence of true and false lumina. (J Am Soc Echocardiogr 1999;12:155-9.)
Subsurface transport of orthophosphate in five agricultural watersheds, USA

Summary Concentrations of dissolved orthophosphate (ortho P) in the unsaturated zone, groundwater, tile drains, and groundwater/stream water interfaces were assessed in five agricultural watersheds to determine the potential for subsurface transport. Concentrations of iron oxides were measured in the aquifer material and adsorption of ortho P on oxide surfaces was assessed by geochemical modeling. Attenuation of ortho P in these aquifers was attributed primarily to sorption onto iron oxides, and in one location onto clay minerals. Only one location showed a clear indication of phosphorus transport to a stream from groundwater discharge, although groundwater did contribute to the stream load elsewhere. Subsurface ortho P movement at a site in California resulted in a plume down gradient from orchards, which was attenuated by a 200 m thick riparian zone with natural vegetation. Iron oxides had an effect on phosphorus movement and concentrations at all locations, and groundwater chemistry, especially pH, exerted a major control on the amount of phosphorus adsorbed. Groundwater pH at a site in Maryland was below 5 and that resulted in complete sequestration of phosphorus and no movement toward the stream. Geochemical modeling indicated that as the surfaces approached saturation, groundwater concentrations of ortho P rise rapidly.
Efficacy of tonsillectomy in treatment of recurrent group A β-hemolytic streptococcal pharyngitis

Objective: The objective of this study was to determine whether children with tonsillectomies experienced fewer recurrent group A β-hemolytic streptococcal (GABHS) infections after surgery compared with children who did not receive tonsillectomies. Study Design/Methods: The authors conducted a retrospective cohort study of 290 children 4 to < 16 years who experienced three or more episodes of group A β-hemolytic streptococcal pharyngitis at least 1 month apart in 12 months. Results: Children without tonsillectomy were 3.1 times (95% confidence interval, 1.9-4.9; P <.001) more likely to develop a subsequent group A β-hemolytic streptococcal pharyngitis infection during follow up than children who underwent tonsillectomy after adjusting for the number of group A β-hemolytic streptococcal pharyngitis infections per patient within the previous year and the presence of preexisting conditions. Among the children who developed a subsequent group A (3-hemolytic streptococcal pharyngitis infection, the children without a tonsillectomy developed a group A β-hemolytic streptococcal pharyngeal infection sooner (median, 0.6 vs. 1.1 years). Conclusions: Tonsillectomy is associated with a decrease in the number of group A β-hemolytic streptococcal pharyngitis infections in children with a history of recurrent groups A β-hemolytic streptococcal pharyngitis infection. Tonsillectomy also increased the amount of time before development of further GABHS pharyngitis.
P‐14: An Image Processing Model of Contrast Perception and Discrimination of the Human Visual System

An multi-layered image processing model of the primary visual system was built to simulate the center-surround effect on apparent contrast perception and contrast discrimination at the suprathreshold level. The simulation revealed that the mechanisms for apparent contrast perception and contrast discrimination were instinctually different. We questioned the reliability of the perceptual image quality models that were based on the results of contrast discrimination experiments.