cssi/SciSciGPT-SciSciNet huggingface dataset:
ATP Synthase: Advantages of the Rotary Mechanism under Diverse Conditions

ATP synthesis based on the proton-motive force (pmf) across mitochondrial and bacterial membranes is a key cellular function performed by the F-ATPase, a complex rotary machine. Although mechanistic details of the F-ATPase have drawn intensive scrutiny, it remains unknown whether the rotary process itself is merely a sufficient outcome of evolution or whether the elaborate rotary mechanism has advantages over other, arguably simpler, mechanisms. For example, ATP-hydrolyzing P-loop transporters can be reversed to perform ATP synthesis, suggesting a variety of potential synthesis mechanisms. The present work uses kinetic models, operating under fundamental biophysical constraints, to compare a rotary-like mechanism for ATP synthesis with a systematic enumeration of alternative mechanisms based on event-ordering; each is constrained to operate under the same H+/ATP ratio and thermodynamic conditions. The models are independent of structural details and rely solely on thermodynamic and kinetic principles. The resulting models qualitatively reproduce key kinetic characteristics of ATP synthase under physiological conditions, including the sigmoidal relationship between the rate of ATP synthesis and pmf. When the mechanisms are separately optimized to maximize the rate of ATP synthesis over a range of presumed physiological conditions, the performance of the rotary mechanism stands out significantly, particularly in the most challenging, energy-poor conditions. Although all the models are thermodynamically equivalent in using the same free energy per ATP synthesized, the rotary model possesses a kinetic advantage: its one-at-a-time transport of protons enables more ratchet-like progress and less delay-induced unbinding of protons on the driving (low-pH) side of the membrane. Our results suggest the rotary mechanism has a quantifiable intrinsic advantage that may have played a role in evolution.
Middle-School Students' Perception of Strategy Use: Putting the Learner Back into Self-Regulated Learning

AbstractThis study examines students' perceptions of personal and behavioral factors believed to influence strategy use and self-regulated learning. Comprehension performance was also examined based upon differences in strategy use, interest and self-regulation. Eighth-grade students (n=11) were interviewed after reading a passage from their social studies textbook. Students were asked about what strategies they had used, and about what factors influenced their strategy use. Results indicate that interest in the text topic was perceived by a majority of students to influence strategy use. Self-observation was related to the type of goal students set during reading. Performance differences were found among students based upon strategy use and self-regulation, but not based upon interest in the text topic. Implications are discussed in terms of classroom strategy training and enhancing middle-school students' motivation.
Magnetic Resonance Imaging of the Myocardium

Magnetic resonance imaging (MRI) is emerging as a method of choice for the evaluation of a variety of cardiovascular disorders. Magnetic resonance imaging provides arguably the best and most comprehensive approach to evaluating the structure and function of the heart. Delayed contrast-enhanced MRI (DE-MRI) provides direct visualization of both non-viable and viable myocardium. It can distinguish between acute infarcts with necrotic myocytes and acute infarcts with necrotic myocytes and damaged microvasculature, or the “no-reflow phenomenon.” Compared with radionuclide techniques such as single photon emission tomography (SPECT), first-pass perfusion MRI offers significantly higher resolution. Perfusion MRI with vasodilator stress is becoming increasingly important in the evaluation of patients with coronary artery disease in clinical practice.
Exploring the Role of Location in Dynamics of the Birth and Death of Business Establishments: Case Study Analysis of Santa Barbara County, California:

Integrated models of land use and transportation are aimed at addressing regional issues related to congestion, mobility, and economic competitiveness. Integral to these model systems is freight transport, which plays a huge role in the economic vitality of the region in the form of distribution and complex interactions between various stakeholders. Within this context, it is therefore critical to capture and describe accurately the behavioral dynamics of these stakeholders (or firms) in the region, including modeling various life-cycle stages, such as birth, death, growth and decline, and migration patterns. This study focused on dynamics of the birth and death of firms by considering as determinants their internal attributes (size, age, and growth) and external attributes, such as market area characteristics, agglomeration economies, transportation access, and network centrality indexes describing advantage, significance, and properties of a location. This microanalysis was based on an assembled panel o...
Conservation Agriculture Systems to Mitigate Climate Variability Effects on Soil Health

Climate change is the greatest challenge of the modern era, and to the use of our fundamental resource of soil and water for food production and security. This threat is to both soil and water, but in this chapter, the focus will be on the impact on soil health. This impact can be intensified by management practices that lead to soil desertification, deforestation, erosion, and other forms of degradation. These dynamics, along with weather variability, such as frequent wet and drought events, are prevalent in different parts of the world. This chapter focuses on the role of conservation agriculture systems in affecting soil biological, chemical, and physical functions to sustain soil health in order to minimize weather variability effects on soil and reduce the negative impacts on productivity. The interaction among different tillage and cropping systems effects on soil structure dynamics and the controlling factors that accelerate the enhancement of soil aggregation are discussed to understand the principal impacts of improving soil structure, taking into consideration soil temperature and moisture regimes, and nutrient availability.
Benchmarking and Metrics for Emerging Memory

Comparison of the dominant emerging memory technologies at the fundamental cell level will be presented. Metrics will be discussed and the technologies will be compared with the objective of judging the suitability for high density memory applications.
Combined MAP-Kalman filter channel estimation algorithm for space-time block coded communication systems

In this paper, we analyze the combined maximum a posteriori (MAP) and Kalman filtering channel estimation/tracking for time-varying Rayleigh fading channels. Pilot symbol assisted modulation is used for initial channel estimation using the MAP algorithm followed by the Kalman filter. Space-time block codes are used as a diversity scheme to combat fading.
Predictors of Reoperation and Failure to Rescue in Bariatric Surgery.

Background and Objectives Morbidity and mortality have been shown to increase several-fold in patients who have undergone bariatric surgery and returned to the operating room after their initial procedures. Failure-to-rescue (FTR) analyses allow for an understanding of patient management and outcomes that is more distinguished than assessments of adverse occurrences and mortality rates alone. The objective of this study was to assess failure to rescue (FTR) and the characteristics and outcomes of patients undergoing reoperation after laparoscopic gastric bypass (LGBP) and laparoscopic sleeve gastrectomy (LSG). Methods The American College of Surgeons-National Surgical Quality Improvement Program (ACS-NSQIP) participant data files were accessed to identify patients >18 years of age who underwent LGBP and LSG from 2011 through 2015. Patients were further classified into 3-day reoperation and nonreoperation cohorts. Patient demographics, comorbidities, and baseline health characteristics were collected. Pertinent outcomes, complications, and FTR were analyzed. Results A total of 96,538 patients were included. Of those, 1,850 (1.92%) returned to the operating room, and 94,688 (98.08%) did not. Patients who underwent reoperation had a greater likelihood of having any complication (72.20% vs. 51.29%; P < .0001) and had a higher overall mortality rate (1.46% vs. 0.10%, P < .0001). The FTR rates were 2.01% in the reoperation group and 0.14% in the nonreoperation group (P < .0001). Conclusion Patients who undergo LGBP and LSG and have reoperations are at higher risk of developing complications with subsequent mortality.
Damping Acoustic Modes in Compressible Horizontally Explicit Vertically Implicit (HEVI) and Split-Explicit Time Integration Schemes

AbstractAlthough the equations of motion for a compressible atmosphere accommodate acoustic waves, these modes typically play an insignificant role in atmospheric processes of physical interest. In numerically integrating the compressible equations, it is often beneficial to filter these acoustic modes to control acoustic noise and prevent its artificial growth. Here, a new technique is proposed for filtering the 3D divergence that may damp acoustic modes more effectively than filters previously implemented in numerical modes using horizontally explicit vertically implicit (HEVI) and split-explicit time integration schemes. With this approach, a divergence damping term is added as a final adjustment to the horizontal velocity at the new time level after completing the vertically implicit portion of the time step. In this manner, the divergence used in the filter term has exactly the same numerical form as that used in the discrete pressure equation. Analysis of the dispersion equation for this form of the...
Listeners compensate for prosodic position when categorizing word-final obstruents

This study explores how perceptual sensitivities to contextual variability extend to prosodically induced variation. In English, vowel duration is reliably longer preceding a voiced obstruent, as opposed to a voiceless obstruent, and listeners use preceding length as a cue to obstruent voicing (e.g. Raphael, 1972). Segmental duration also co-varies systematically with prosodic position, being longer phrase-finally (e.g. Turk & Shattuck-Hufnagel, 2007). In this study, we tested the extent to which listeners’ categorization of word-final obstruents is altered by the prosodic position of the target. Participants heard a continuum that varied only in vowel length, and categorized stimuli as either “coat” or “code”. Prosodic position in a carrier phrase was manipulated by splicing the target word into either a phrase-final or phrase-medial context. Results show listener expectations about phrase final lengthening mediate categorization, with significantly longer vowel durations required in phrase-final position for a “code” response. The results are discussed in terms of other top-down influences on segmental categorization (e.g. lexical information), and implications for further work on the prosody-phonetics interface.This study explores how perceptual sensitivities to contextual variability extend to prosodically induced variation. In English, vowel duration is reliably longer preceding a voiced obstruent, as opposed to a voiceless obstruent, and listeners use preceding length as a cue to obstruent voicing (e.g. Raphael, 1972). Segmental duration also co-varies systematically with prosodic position, being longer phrase-finally (e.g. Turk & Shattuck-Hufnagel, 2007). In this study, we tested the extent to which listeners’ categorization of word-final obstruents is altered by the prosodic position of the target. Participants heard a continuum that varied only in vowel length, and categorized stimuli as either “coat” or “code”. Prosodic position in a carrier phrase was manipulated by splicing the target word into either a phrase-final or phrase-medial context. Results show listener expectations about phrase final lengthening mediate categorization, with significantly longer vowel durations required in phrase-final positio...
The Economic Evaluation of Solid Waste Management Options

Issues crucial to the successful implementation of a municipal solid waste (MSW) management program are reviewed. As one of the major responsibilities of local government, management of MSW can require utilization of a substantial portion of community resources, so it is in the interest of the community to undertake careful economic evaluation of all alternative waste solutions. Evaluation should extend beyond the assessment of physical performance and service outputs, to consider the manner by which the services are delivered in terms of economic efficiency. Generally these goals will consist of efficiency, reliability, environmental stability and equity.
From Stochastic Planning to Marginal MAP

It is well known that the problems of stochastic planning and probabilistic inference are closely related. This paper makes two contributions in this context. The first is to provide an analysis of the recently developed SOGBOFA heuristic planning algorithm that was shown to be effective for problems with large factored state and action spaces. It is shown that SOGBOFA can be seen as a specialized inference algorithm that computes its solutions through a combination of a symbolic variant of belief propagation and gradient ascent. The second contribution is a new solver for Marginal MAP (MMAP) inference. We introduce a new reduction from MMAP to maximum expected utility problems which are suitable for the symbolic computation in SOGBOFA. This yields a novel algebraic gradient-based solver (AGS) for MMAP. An experimental evaluation illustrates the potential of AGS in solving difficult MMAP problems.
Data paper: FoRAGE (Functional Responses from Around the Globe in all Ecosystems) database: a compilation of functional responses for consumers and parasitoids

Functional responses - the relationships between consumer foraging rate and resource (prey) density - provide key insights into consumer-resource interactions and predation mechanics while also being a major contributor to population dynamics and food web structure. We present a global database of standardized functional response parameters extracted from the published literature. We refit the functional responses with a Type II model using standardized methods and report the fitted parameters along with data on experimental conditions, consumer and resource taxonomy and type, as well as the habitat and dimensionality of the foraging interaction. The consumer and resource species covered here are taxonomically diverse, from protozoans filtering algae to wasps parasitizing moth larvae to wolves hunting moose. The FoRAGE database (doi:10.5063/F17H1GTQ) is a living data set that will be updated periodically as new functional responses are published.
Smart Walker for the Visually Impaired

Visually impaired individuals often employ canes or guide dogs to help navigate complex environments. Individuals who are both visually and mobility impaired encounter greater difficulty, since conventional aids do not integrate well with walkers or rollators. In this paper we propose a smart walker architecture that is augmented with depth-sensing cameras that detect and recognize obstacles that may endanger the user, as well as obtain their distance from the user. This information is conveyed to the user through a haptic interface on the walker. Our design helps protect the user from colliding with obstacles in his&#x002F;her path. In comparison with traditional mobility methods, the smart walker allows the user to navigate the environment faster and with less physical and cognitive load. Compared to previous designs, our approach completes this task at a significantly lower cost per unit.
Impact of the design of visual communication supports on social interaction by individuals with Down syndrome

Many individuals with developmental disabilities have difficulty using speech as their primary method of communication. These individuals often use visual communication technologies that produce speech when symbols (letters, icons) are typed or selected. When an external aid is used to assist with message preparation, it is called aided augmentative and alternative communication (AAC). The current report illustrates how the design of AAC displays can influence both the efficiency of visual attention to the displays, and also the rate and flexibility of communication produced by three young adults with Down syndrome while using these displays. We designed three versions of AAC displays that prior laboratory research has indicated would influence efficiency of visual attention. These displays were then each used to support communication during a storybook reading interaction between individuals with Down syndrome and a trained communication partner. Visual attention was measured via mobile eye-tracking technologies, and communication behavior was recorded via video camera. Greater efficiency of visual attention and more frequent and flexible communication was observed when the AAC display was optimally designed. The results illustrate the value of eye-tracking technologies for examining communication behavior using AAC.
Vestige: Identifying Binary Code Provenance for Vulnerability Detection

Identifying the compilation provenance of a binary code helps to pinpoint the specific compilation tools and configurations that were used to produce the executable. Unfortunately, existing techniques are not able to accurately differentiate among closely related executables, especially those generated with minor different compiling configurations. To address this problem, we have designed a new provenance identification system, Vestige. We build a new representation of the binary code, i.e., attributed function call graph (AFCG), that covers three types of features: idiom features at the instruction level, graphlet features at the function level, and function call graph at the binary level. Vestige applies a graph neural network model on the AFCG and generates representative embeddings for provenance identification. The experiment shows that Vestige achieves 96% accuracy on the publicly available datasets of more than 6,000 binaries, which is significantly better than previous works. When applied for binary code vulnerability detection, Vestige can help to improve the top-1 hit rate of three recent code vulnerability detection methods by up to 27%.
Low Temperature Curable Low Dk & Df Polyimide for Millimeter-Wave Device

In this paper, we developed novel low temperature curable (around 200∼250 °C) low Dk (2.7) & Df (0.002) polyimide with high glass transition temperature (Tg) and elongation. Tg and elongation of the polyimide is 175°C and 100% respectively. The non-photosensitive polyimide can be patterned by laser ablation and imprint process. We also developed negative tone photosensitive polyimide with low Dk & Df by photo initiator and cross linker. To confirm effect of the novel polyimide, we measured insertion loss of micro-strip line using the new developed polyimide. We found that insertion loss (S21 parameter) was less than half of conventional polyimide. We also measured insertion loss the micro-strip line circuit after being immersed in water at room temperature for 48 hours, and found that the loss didn't change even after the treatment. We investigated the frequency dependence of the novel low Dk & Df polyimide up to 95 GHz, and confirmed that Df gradually increased from 0.002 to 0.005 as the frequency increased. The developed PI shows high adhesion strength (6N/mm) to smooth surface copper foil whose roughness is 1um. These properties of the novel polyimide indicated it is suitable to insulator of RDL for FO-AiP
Some considerations for high-order 'incremental remap'-based transport schemes: Edges, reconstructions, and area integration

The problem of two-dimensional tracer advection on the sphere is extremely important in modeling of geophysical fluids and has been tackled using a variety of approaches. A class of popular approaches for tracer advection include ‘incremental remap’ or cell-integrated semi-Lagrangian-type schemes. These schemes achieve high-order accuracy without the need for multistage integration in time, are capable of large time steps, and tend to be more efficient than other high-order transport schemes when applied to a large number of tracers over a single velocity field. In this paper, the simplified flux-form implementation of the Conservative Semi-LAgrangian Multi-tracer scheme (CSLAM) is reformulated using quadratic curves to approximate the upstream flux volumes and Gaussian quadrature for integrating the edge flux. The high-order treatment of edge fluxes is motivated because of poor accuracy of the CSLAM scheme in the presence of strong nonlinear shear, such as one might observe in the midlatitudes near an atmospheric jet. Without the quadratic treatment of upstream edges, we observe at most second-order accuracy under convergence of grid resolution, which is returned to third-order accuracy under the improved treatment. A shallow-water barotropic instability also reveals clear evidence of grid imprinting without the quadratic correction. Consequently, these tests reveal a problem that might arise in tracer transport near nonlinearly sheared regions of the real atmosphere, particularly near cubed-sphere panel edges. Although CSLAM is used as the foundation for this analysis, the conclusions of this paper are applicable to the general class of incremental remap schemes. Copyright © 2012 John Wiley & Sons, Ltd.
A cellular automaton model of excitable media. II: curvature, dispersion, rotating waves and meandering waves

Abstract A cellular automaton model of excitable media, recently introduced by the authors, is examined in more detail here. We show that (i) the model is consistent with a linear dependence of wave speed on wave-front curvature in two-dimensional space, (ii) the model exhibits a stepwise increasing relation between wave speed and temporal period (the “dispersion” relation), whose precise shape can be controlled by parameter settings, (iii) the model generates rigidly rotating spiral waves whose frequency, speed, and core size are consistent with theoretical expectations, and (iv) spiral waves rotate non-rigidly, showing short-term “flowerlet” meandering which seems to arise by bifurcation from the rigidly rotating solution, and long-term irregular “wandering” over large distances. These observations are consistent with many known features of wave propagation in two-dimensional, continuous excitable media governed by reaction-diffusion equations, suggesting that our cellular automaton model is not only a fast but also a reliable method for investigating the behavior of excitable media.
Sexual Offenders/Pedophilia

Given the disturbing nature of sexual offenses, it is understandable that sex crimes are a topic of great concern within our communities and among policymakers. There are, however, many misperceptions about sex offenders, and these misperceptions often impact the public's understanding of sex crimes and our ability to effectively manage sexual violence in the community. It is important for community members and policymakers to be aware of empirical knowledge pertaining to sex offenders—not stereotypes or myths—as this can assist in developing more effective policy and ultimately, contribute to the prevention of sexual violence in our communities. Keywords: cognitive behavior therapy; pedophilia; risk assessment; sex crime; sex offender treatment; sex offenders; sexual deviance; sexual violence; violent offenders
Cholesterol: stuck in traffic

Niemann–Pick type C is a genetic disorder thought to be partly characterized by a defect in cholesterol storage in lysosomes. New findings show that in fact cholesterol accumulates in late endosomes, and this accumulation leads to the redistribution of membrane proteins.
Pulmonary manifestations of renal cell carcinoma

Renal cell carcinoma (RCC) accounts for majority of all primary renal neoplasms. Classic manifestations of RCC include the triad of flank pain, hematuria and a palpable renal mass. Patients with RCC can develop various extra renal manifestations including involvements of the lungs, inferior vena cava, liver and the bones. The pulmonary manifestations of renal cell carcinoma include metastatic disease including endobronchial, pleural, parenchymal or lymph node metastasis, pleural effusion or hemothorax. Pulmonary embolism and tumor embolism is another common manifestation of renal cell carcinoma. RCC is a highly vascular tumor and can cause pulmonary arterio-venous fistulas leading to high output failure. Rarely, RCC can also present with paraneoplastic presentations including cough or bilateral diaphragm paralysis. Drugs used to treat RCC have been associated with drug related pneumonitis and form an important differential diagnosis in patients with RCC on therapy presenting with shortness of breath. In this review we discuss the various pulmonary manifestations of RCC. A high index of suspicion with these presentations can lead to an early diagnosis and assist in instituting an appropriate intervention.
An object-oriented integrated software analysis and maintenance

The author has developed a multiuser integrated software analysis and maintenance system, called SAMS, on top of an object-oriented DBMS. SAMS models the description of the various aspects of software systems by persistent object types and implements different software tools by operations of objects. Software systems which are maintained by using SAMS are represented by object instances. SAMS tightly integrates various software analysis and maintenance functions such as cross referencing, annotating and configuration management around an automatically generated object-oriented software database system. Its high-level user interface delivers various analysis and maintenance functions to end users, without exposing its internals and implementation characteristics. Its tool set allows existing software to be loaded into the database automatically. SAMS's database schema contains approximately 400 classes with thousands of attributes and methods. >
Conflict resolution in AGV systems

Currently, conflict-free routing in AGV systems is established by means of one of the following three approaches: (i) the problem elimination through the adoption of a segmented path flow or tandem queue configuration; (ii) the identification of imminent collisions through forward sensing and their aversion through vehicle backtracking and/or rerouting; or (iii) the imposition of zone control and extensive route pre-planning, typically based on deterministic timing of the vehicle traveling and docking stages. Among these three approaches, the segmented path flow-based approach presents the highest robustness to the system stochasticities/randomness, but at the cost of restricted vehicle routings and the need for complicated handling operations. This paper proposes an alternative conflict resolution strategy that will ensure robust AGV conflict resolution, while maintaining the operational flexibility provided by free vehicle travel on arbitrarily structured guidepath networks. Specifically, the approach advocated in this paper also employs zone control, but it determines vehicle routes incrementally, one zone at a time. Routing decisions are the result of a sequence of safety and performance considerations, with the former being primarily based on structural/logical rather than timing aspects of the system behavior. The resulting control problem is characterized as the AGV structural control. After defining the notion of AGV structural control, the paper proceeds to the formal characterization and analysis of the problem, and to the development of a structural control policy appropriate for the class of AGV resource allocation systems. The paper concludes with some discussion on the accommodation of emerging AGV operational features in the proposed modeling and analysis framework, and the integration of AGV structural control with the broader control of material-flow among the shop-floor workstations.
MicroRNA control of epithelial–mesenchymal transition and metastasis

The great majority of cancer deaths are due to metastasis, which remains a poorly understood pathological process. The formation of a metastasis reflects a succession of complex steps leading to the macroscopic outgrowth of disseminated tumor cells at the secondary site. In the past 5 years, certain microRNAs (miRNAs) have been shown to regulate either a single step or multiple steps of metastasis, doing so by downregulating the expression of their target genes. In this review, we discuss recent studies on the functions and molecular mechanisms of miRNAs in regulating epithelial–mesenchymal transition (EMT) and cancer metastasis.
Stochastic modeling of leak detection and localization using ultrasonic sensor array

Leak detection and localization appears in many engineering applications such as aerospace and engineering industries. Existing approaches for leak detection and localization from surface borne ultrasonic signals are based on triangulation techniques [1], [2]. Ultrasonic signals are prone to reverberation and multipath effect since they are reflected from various surfaces of the structure. Reverberation and multipath generates multiple detections for each sensor. Therefore, the sensor measure signals with uncertain origin signals, where the conventional algorithms based on triangulation techniques can not be applied.
SPF model applications for aluminum

A closed-form, plane strain model (PS2) is compared with a finite element model (SUPFORM3) in analyzing the forming of rectangular pans from 2090-OE16 aluminum sheet. The errors introduced by improperly using a plane strain model are quantified. Some preliminary verification of SUPFORM3 is shown, and the effect of friction on the distribution of thickness in the superplastic forming (SPF) of a rectangular pan is presented.
Synthesis and Reactivity of 10- and 12-Vertex Cobalt−Monocarborane Anions Containing Multiple Metal Centers

Treatment of [closo-1-CB7H8]- with [Co2(CO)8] in THF at room temperature affords the 10-vertex dicobalt−monocarbollide anion [6,10-(μ-CO)-6,6,10,10-(CO)4-closo-6,10,1-Co2CB7H8]-, isolated as the [N(PPh3)2]+ salt (6). The analogous 12-vertex species [N(PPh3)2][2,3-(μ-CO)-2,2,3,3-(CO)4-closo-2,3,1-Co2CB9H10] (7) is obtained similarly from [arachno-6-CB9H14]- and [Co2(CO)8] heated to 50 °C. Both 6 and 7 contain a cobalt−cobalt bond that is bridged by one CO ligand. In contrast, the same cobalt reagent with [closo-4-CB8H9]- at room temperature gives the tricobalt species [6,7,10-{Co2(μ-CO)(CO)5}-7-(μ-H)-6,6-(CO)2-closo-6,1-CoCB8H7]-, similarly isolated as its [N(PPh3)2]+ salt (8a). The latter contains a V-shaped tricobalt unit, part of a {Co3B} butterfly that is edge-fused to a {CoCB8} cluster. Compounds 6 and 7 with CF3SO3Me in CH2Cl2−THF (1:1) give the zwitterionic, B-substituted complexes [6,10-(μ-CO)-6,6,10,10-(CO)4-8-{O(CH2)4}-closo-6,10,1-Co2CB7H7] (9) and [2,3-(μ-CO)-2,2,3,3-(CO)4-12-{O(CH2)4}-closo-2,...
Sizing up earth: A universal method for applying eratosthenes' earth measurement

Abstract This article is based on an activity used in a team-taught preservice course, “Integrating Geography and History,” at the University of North Alabama. The antecedents to modern descriptions and calculations of earth's shape and size began more than 2,000 years ago. The Greek mathematician and geographer Eratosthenes made the most accurate ancient measurement of Earth based on fundamental math concepts and Earth-Sun relations that provided a basis for determining latitude with greater accuracy. A brief historical statement about Eratosthenes' experiment is followed by an extended explanation of how teachers can use Eratosthenes' method in the classroom to calculate the size of Earth using shadows and simple mathematics independent of noon time observations.
Mass spectrometric evidence for HO2 in 1 atm flames

Abstract The perhydroxyl species HO 2 has been observed in 1 atm H 2 O 2 N 2 flames and its flame concentration determined as a function of flame composition and position. Also the oxidation of small additions of CO to these flames has been observed and the results favor the reaction, OH + CO → CO 2 + H, rather than the alternative process, HO 2 + CO → CO 2 + OH.
The mussel watch: Intercomparison of trace level constituent determinations

The U.S. National Mussel Watch Program initially used split-sample analyses for interlaboratory quality control purposes. These indicated the possibility of interlaboratory analytical discrepancies as well as problems in the split-sample technique itself. For the third year of the program, two mussel homogenates were produced to serve as intercomparison samples — one for metals and organics, the other for radionuclides. The results obtained using these homogenates are encouraging in that generally good agreement is seen among analyses done by several labs in diverse pollutant classes. We conclude from this experience that a quality-control program relying on the analysis of large homogeneous samples of the matrix being dealt with is an essential part of any extensive, multilaboratory analytical program.
13 Years Experience With Congenital Diaphragmatic Hernia (CDH) in a Large Inborn Population. 1521

13 Years Experience With Congenital Diaphragmatic Hernia (CDH) in a Large Inborn Population. 1521
Nuclear Magnetic Resonance Characterization of the Myristoylated, N-Terminal Fragment of ADP-Ribosylation Factor 1 in a Magnetically Oriented Membrane Array†

The behavior of the N-terminal fragment of human ADP-ribosylation factor 1 (ARF1) in a membranelike environment is described. This is accomplished using heteronuclear liquid crystal NMR techniques in a magnetically oriented membrane array on a selectively 13C- and 15N-labeled peptide. After full assignment of the labeled sites, residual dipolar couplings (13C−13C, 15N−1H and, 13C−15N) and chemical shift anisotropy effects (amide 13C and 15N) were measured. The experimental data were interpreted using order matrix calculations to yield orientational and dynamic information for four separate, rigid amide planes. The experimental data obtained proves that the amphipathic peptide interacts with the bilayer in a mode that is consistent with an α-helix having its axis parallel to the membrane surface. Possibilities of extending the employed techniques to larger and uniformly labeled systems are discussed.
Better function for fusions versus above-the-knee amputations for recurrent periprosthetic knee infection

Background Treatment of chronic periprosthetic joint infections (PJIs) after TKA is limited to fusions, above-the-knee amputations (AKAs), revision TKA, and antibiotic suppression and is often based on the patient’s medical condition. However, when both fusion and AKA are options, it is important to compare these two procedures with regard to function.
Synthesis of morpholinium [13C] formate and its application in the synthesis of [8‐13C] purine base

Morpholinium [13C]formate is obtained by neutralizing an aqueous solution of equivalent amounts of sodium [13C]formate and hydrochloric acid with morpholine. Morpholinium [13C]formate is isolated in crystalline form and characterized. Treatment of 6-hydroxy-2,4,5-triaminopyrimidine sulfate with morpholinium [13C]formate at 200° affords [8-13C]guanine in 80% yield. There is no necessity to synthesize and isolate [13C]-N-formylmorpholine and the intermediate N5-[13C]formyl pyrimidine derivative. Mass spectrometric analysis shows that the molar isotopic concentration of 13C label in guanine is identical to that of the morpholinium [13C]formate and there is no isotopic scrambling. The same procedure when used with 4,5,6-triaminopyrimidine sulfate affords adenine in 85% yield.
BUREAUCRATIC DECENTRALIZATION AND THE REDISTRIBUTION OF URBAN SERVICES: THE CASE OF TEAM POLICING1

Two extreme positions dominate the decentralization debate in urban politics: one school consistently opposes decentralization, while the other maintains that only complete radical community control can solve the problems of politics and administration in the city. Positions and policies between these two extremes tend to get lost in rhetoric and argument, or receive only passing recognition. This paper is an attempt to carve out, theoretically and empirically, some space for an intermediate position. Following a brief exploration of the decentralization debate, we discuss and present some analysis from a team policing experiment, a type of ecentralization that falls in between the two extremes. The data suggest that this type of decentralization can be successful if the program is designed as a non-zero-sum game, and the paper concludes that intermediate programs represent attractive third choices to discredited or unworkable alternatives.
Regulatory B cells inhibit cytotoxic T lymphocyte (CTL) activity and elimination of infected CD4 T cells after in vitro reactivation of HIV latent reservoirs.

During HIV infection, IL-10/IL-10 receptor and programmed death-1 (PD-1)/programmed death-1-ligand (PD-L1) interactions have been implicated in the impairment of cytotoxic T lymphocyte (CTL) activity. Despite antiretroviral therapy (ART), attenuated anti-HIV CTL functions present a major hurdle towards curative measures requiring viral eradication. Therefore, deeper understanding of the mechanisms underlying impaired CTL is crucial before HIV viral eradication is viable. The generation of robust CTL activity necessitates interactions between antigen-presenting cells (APC), CD4+ and CD8+ T cells. We have shown that in vitro, IL-10hiPD-L1hi regulatory B cells (Bregs) directly attenuate HIV-specific CD8+-mediated CTL activity. Bregs also modulate APC and CD4+ T cell function; herein we characterize the Breg compartment in uninfected (HIVNEG), HIV-infected “elite controllers” (HIVEC), ART-treated (HIVART), and viremic (HIVvir), subjects, and in vitro, assess the impact of Bregs on anti-HIV CTL generation and activity after reactivation of HIV latent reservoirs using suberoylanilide hydroxamic acid (SAHA). We find that Bregs from HIVEC and HIVART subjects exhibit comparable IL-10 expression levels significantly higher than HIVNEG subjects, but significantly lower than HIVVIR subjects. Bregs from HIVEC and HIVART subjects exhibit comparable PD-L1 expression, significantly higher than in HIVVIR and HIVNEG subjects. SAHA-treated Breg-depleted PBMC from HIVEC and HIVART subjects, displayed enhanced CD4+ T-cell proliferation, significant upregulation of antigen-presentation molecules, increased frequency of CD107a+ and HIV-specific CD8+ T cells, associated with efficient elimination of infected CD4+ T cells, and reduction in integrated viral DNA. Finally, IL-10-R and PD-1 antibody blockade partially reversed Breg-mediated inhibition of CD4+ T-cell proliferation. Our data suggest that, possibly, via an IL-10 and PD-L1 synergistic mechanism; Bregs likely inhibit APC function and CD4+ T-cell proliferation, leading to anti-HIV CTL attenuation, hindering viral eradication.
Contractile function and myoplasmic free Ca2+ (Cam) in coronary and mesenteric arteries of endotoxemic guinea pigs.

Endotoxin-induced vascular hyporesponsiveness could potentially involve alterations of vascular smooth muscle (VSM) myoplasmic free calcium (Ca(m)) mobilization mechanisms. Contractile function and Ca(m)(fura-2 microfluorometry) regulation were evaluated in vitro using coronary (COR) and mesenteric (MES) artery preparations (100-250 microm inner diameter) isolated from guinea pigs 16 h after intraperitoneal (i.p.) injection of either saline (control; CON) or Escherichia coli endotoxin lipopolysaccharide (LPS; 4 mg/kg). Concentration-response relationships to K+ (5-100 mM) were significantly enhanced in both COR and MES arteries isolated from LPS-treated animals. In contrast, contractile responses to prostaglandin F2alpha (PGF2alpha; 1-100 microM) were markedly impaired in COR and MES arteries from LPS-treated animals, while endothelin-1 (ET; 1-100 nM)-mediated contractile responses of these arteries were enhanced at the maximal dose (100 nM). In COR arteries, PGF2alpha (1-100 microM) and ET (1-100 nM) produced biphasic increases in Ca(m) in both CON and LPS groups. No significant differences were observed in either the initial transient peak or secondary sustained Ca(m) responses between groups, suggesting a lack of effect of LPS upon intracellular Ca2+ release or Ca2+ influx mechanisms in COR arteries. Exposure of MES arteries to PGF2alpha and ET produced concentration-dependent increases in Ca(m) in both groups. However, Ca(m) responses of MES arteries lacked initial peak responses, suggesting potential differences in Ca(m) mobilization between COR and MES arteries. Ca(m) responses to K+ (80 mM) and PGF2alpha (1-100 microM) were similar in MES arteries from both groups; however, ET-mediated increases in Ca(m) were significantly blunted in LPS compared with CON MES arteries. Thus, endotoxemia produced differential effects upon depolarization (K4) and receptor (PGF2alpha, ET)-mediated contractile responses in both COR and MES arteries. Reductions in VSM Ca(m) mobilization appear unlikely as a mechanism for LPS-induced impairment of contractile function of COR and MES arteries; other mechanisms (i.e., decreased Ca2+ sensitivity of contractile proteins) may be involved in effects of LPS upon VSM function of COR and MES arteries.
Macrophyte colonization in a freshwater tidal wetland (Lyme, CT, USA)

Seed bank sampling and creation of plots cleared of standing vegetation showed that aboveground vegetative propagules were more important than seeds in colonization of a freshwater tidal wetland but that the relative importance of sexual reproduction varied among species. Nine submerged species established in colonization plots. Of these colonization events, 60% were achieved by plant fragments, either in the sediment or floating in the water, and 16% resulted from vegetative growth. Only 4 of 16 submerged species in the community were represented in the seed bank. The collection of vegetative propagules in nets demonstrated that drifting propagules were very abundant and that the relative abundance of species in the propagule stream corresponded most closely with the standing community.
Afghanistan: Retribalization of the War*

forces and their domestic allies. But in the midst of the continuing conflict, attempts to limit the war were noticeable and appeared in some areas to take the shape of an emerging system of peace: enduring attempts to conclude local ceasefires and formulate political compromises. The emerging attempts to limit war were related to traditional mechanisms in civil society and to the contemporary fragmentation of state power. The forces encouraging a more unrestrained war, on the other hand, reflected the internationalization of the conflict which took new forms after the Soviet troop
Minimum Node Degree and k-Connectivity in Wireless Networks with Unreliable Links

In this paper, we consider a wireless network with unreliable links and investigate its minimum node degree and k- connectivity. In such network, n nodes are uniformly distributed in a region, and edges are established for any two nodes within a certain distance and with a probabilistically active link in between. On a torus topology, we present a zero-one law for the property of minimum degree being at least k, leading to a zero-law for k-connectivity and an intermediate result towards a one-law. On a square with boundary effect, we establish a one- law for minimum degree. Our results are derived from rigorous analysis and also confirmed by the simulation, and they provide guidelines for the design of wireless networks. Index Terms—Connectivity, Erdos-Renyi graph, geometric graph, graph intersection, minimum node degree, random graph, unreliable link, wireless network, zero-one law.
Laser surface processing of molybdenum disulfide thin films

Abstract We have investigated pulsed laser processing of textured MoS2 thin films using excimer radiation at 248 nm wavelength. The films show little change in their crystallographic orientation even after melting and resolidification as determined by X-ray diffraction. The morphology of the films both on the surface and in cross-section is changed somewhat, particularly in the case of melted films, although the planarity of the films is not. Laser processing at high fluences removes material from the surface but does not change the stoichiometry of the remaining film. Measurements of mass loss both by weight loss and by Rutherford backscattering show that the density of the films is unchanged by the processing. The absence of density change is confirmed by the strength of the X-ray diffraction signal. Processed and unprocessed films show no significant difference in wear life. Small spot X-ray photoelectron and Raman spectroscopies of the films indicate that a portion of the surface decomposes, but that MoO3 incorporation in the film is decreased. The stability of the films under energetic laser processing raises the possibility of using this technique to incorporate other materials into the films or to increase substrate-film adhesion.
Front propagation at low temperatures and multiscale modeling for the catalytic combustion of H2 on Pt

Abstract A skeleton elementary reaction mechanism is employed in a molecular model (kinetic Monte Carlo simulation) and tested against spatially resolved scanning tunneling microscopy data for the first time during wave propagation in the catalytic combustion of H 2 on a Pt surface at low temperatures. It is shown that while the predicted wave propagation is in qualitative agreement with experimental observations, this mechanism cannot predict quantitatively patterns on catalytic surfaces at low temperatures. Multiscale, hybrid (stochastic coupled with deterministic) simulations for the Pt combustion of H 2 in a CSTR are then carried out using complex surface chemistry of 13 elementary reactions. It is found that while a continuum model based on a mean field description of the surface is adequate to predict ignition, large discrepancies from the multiscale predictions are observed on the ignited branch and for the extinction temperature due to adjacency requirements at the microscopic level.
Prediction of uncertainties in atmospheric properties measured by radio occultation experiments

Abstract Radio occultations are commonly used to determine vertical profiles of ionospheric electron density and neutral atmospheric density from measurements of frequency. Previous work has developed expressions for how uncertainties in electron density and neutral density depend on uncertainty in frequency. However, these expressions assume that the relevant density decreases exponentially with increasing altitude, which limits their applicability. Here we develop alternative expressions for uncertainties in radio occultation experiments. We find that uncertainties depend on the vertical resolution. We validate these expressions on radio occultation observations by Mars Global Surveyor and MAVEN. These expressions can be used to perform preliminary design studies of future radio occultation experiments.