cssi/SciSciGPT-SciSciNet huggingface dataset:
Reflection and transmission of electromagnetic pulses at a planar dielectric interface -- theory and quantum lattice simulations

There is considerable interest in the application of quantum information science to advance computations in plasma physics. A particular point of curiosity is whether it is possible to take advantage of quantum computers to speed up numerical simulations relative to conventional computers. Many of the topics in fusion plasma physics are classical in nature. In order to implement them on quantum computers, it will require couching a classical problem in the language of quantum mechanics. Electromagnetic waves are routinely used in fusion experiments to heat a plasma or to generate currents in the plasma. The propagation of electromagnetic waves is described by Maxwell equations with an appropriate description of the plasma as a dielectric medium. Before advancing to the tensor dielectric of a magnetized plasma, this paper considers electromagnetic wave propagation in a one-dimensional inhomogeneous scalar dielectric. The classic theory of scattering of plane electromagnetic waves at a planar interface, separating two different dielectric media, leads to Fresnel equations for reflection and transmission coefficients. In contrast to plane waves, this paper is on the reflection and transmission of a spatially confined electromagnetic pulse. Following an analytical formulation for the scattering of a Gaussian pulse, it is deduced that the maximum transmission coefficient for a pulse is n2/n1 times that for a plane wave; the incident and transmitted pulses propagate in dielectric media with refractive indices n1 and n2, respectively. The analytical theory is complemented by numerical simulations using a quantum lattice algorithm for Maxwell equations. The algorithm, based on the Riemann–Silberstein–Weber representation of the electromagnetic fields and expressed in terms of qubits, is an interleaved sequence of entangling operators at each lattice site and unitary streaming operators, which transmit information from one site to an adjacent lattice site. Besides substantiating results from the theory for Gaussian pulses, numerical simulations show their validity for non-Gaussian pulses. Apart from their time-asymptotic forms, the simulations display an interplay between the incident, reflected, and transmitted pulses in the vicinity of the transition region between two dielectric media.
Efficient Frequency Doubling with Active Stabilization on Chip

Thin-film lithium niobate (TFLN) is superior for integrated nanophotonics due to its outstanding properties in nearly all aspects: strong second-order nonlinearity, fast and efficient electro-optic effects, wide transparency window, and little two photon absorption and free carrier scattering. Together, they permit highly integrated nanophotonic circuits capable of complex photonic processing by incorporating disparate elements on the same chip. Yet, there has to be a demonstration that synergizes those superior properties for system advantage. Here we demonstrate such a chip that capitalizes on TFLNs favorable ferroelectricity, high second-order nonlinearity, and strong electro-optic effects. It consists of a monolithic circuit integrating a Z-cut, quasi-phase matched microring with high quality factor and a phase modulator used in active feedback control. By Pound-Drever-Hall locking, it realizes stable frequency doubling at about 50% conversion with only milliwatt pump, marking the highest by far among all nanophotonic platforms with milliwatt pumping. Our demonstration addresses a long-outstanding challenge facing cavity-based optical processing, including frequency conversion, frequency comb generation, and all-optical switching, whose stable performance is hindered by photorefractive or thermal effects. Our results further establish TFLN as an excellent material capable of optical multitasking, as desirable to build multi-functional chip devices.
Roughness-induced critical phenomenon analogy for turbulent friction factor explained by a co-spectral budget model

Drawing on an analogy to critical phenomena, it was shown that the Nikuradse turbulent friction factor (ft) measurements in pipes of radius R and wall roughness r can be collapsed onto a one-dimensional curve expressed as a conveyance law ftRe1/4=go(χ), where Re is the bulk Reynolds number and χ=Re3/4(r/R). The implicit function go(.) was conjectured based on matching two asymptotic limits of ft. However, the connection between go(.) and the phenomenon it proclaims to represent—turbulent eddies—remains lacking. Using models for the wall-normal velocity spectrum and return-to-isotropy for pressure–strain effects to close a co-spectral density budget, a derivation of go(.) is offered. The proposed method explicitly derives the solution for the conveyance law and provides a physical interpretation of χ as a dimensionless length scale reflecting the competition between the viscous sublayer thickness and characteristic height of roughness elements. Applications of the proposed method to other published measurements spanning roughness and Reynolds numbers beyond the original Nikuradse range are further discussed.
Field-Based Plot Extraction Using UAV RGB Images

Unmanned Aerial Vehicles (UAVs) have become popular for use in plant phenotyping of field based crops, such as maize and sorghum, due to their ability to acquire high resolution data over field trials. Field experiments, which may comprise thousands of plants, are planted according to experimental designs to evaluate varieties or management practices. For many types of phenotyping analysis, we examine smaller groups of plants known as "plots." In this paper, we propose a new plot extraction method that will segment a UAV image into plots. We will demonstrate that our method achieves higher plot extraction accuracy than existing approaches.
Dynamics of science under period of crisis and environmental threat

Abstract. The purpose of this study here is to explain the dynamics and characteristics of research fields in the presence of crisis. This paper focuses on effects of global pandemic crisis of COVID-19 (Coronavirus Disease 2019) in science dynamics. Results suggest that crisis-driven research field is characterized by an unparalleled velocity of scientific production that supports scientific and technological advances, open access and document type with short notes and papers. Understanding the dynamics of science and its consequences during the crisis is of critical importance for planning and allocating resources toward positive societal impact. Keywords. Dynamics of science, Research field, COVID-19, Pandemic crisis, Environmental threats, Crisis management, Scientific advances, Technological change. JEL. F21, F68, O53, K23 .
LENS: Layer Distribution Enabled Neural Architecture Search in Edge-Cloud Hierarchies

Edge-Cloud hierarchical systems employing intelligence through Deep Neural Networks (DNNs) endure the dilemma of workload distribution within them. Previous solutions proposed to distribute workloads at runtime according to the state of the surroundings, like the wireless conditions. However, such conditions are usually overlooked at design time. This paper addresses this issue for DNN architectural design by presenting a novel methodology, LENS, which administers multi-objective Neural Architecture Search (NAS) for two-tiered systems, where the performance objectives are refashioned to consider the wireless communication parameters. From our experimental search space, we demonstrate that LENS improves upon the traditional solution’s Pareto set by 76.47% and 75% with respect to the energy and latency metrics, respectively.
Bottom Tetraquark Production at RHIC

Background: A resonance has been observed by the ANDY Collaboration at the Relativistic Heavy-Ion Collider at Brookhaven National Laboratory in Cu+Au collisions at center-of-mass energy $\sqrt{s} = 200$ GeV and at forward rapidity with an average mass of 18.15 GeV. The Collaboration suggests that it is a $b \overline b b \overline b$ tetraquark state decaying to two $\Upsilon$(1S) states, each measured through the $\Upsilon \rightarrow ggg$ channel. Purpose: Their suggestion is investigated assuming that the two $\Upsilon$ states are produced through the materialization of a $|uud b\overline b b \overline b \rangle$ Fock state in the projectile. Methods: The $\Upsilon$ pair mass and rapidity distributions arising from such a state are calculated. The production of an $X_b(b \overline b b \overline b)$ tetraquark state from the same Fock configuration is also investigated. The dependence on bottom quark mass and their transverse momentum range is also studied. Results: It is found that double $\Upsilon$ production from these $|uud b \overline b b \overline b \rangle$ states peak in the rapidity range of the ANDY detector. The $\Upsilon$ pair and $X_b$ masses are, however, higher than the mass reported by the ANDY Collaboration. Conclusions: The results obtained from these calculations are incompatible with the ANDY result. They are, however, compatible with previous predictions of $b \overline b b \overline b$ tetraquark masses.
AppSlice: A system for application-centric design of 5G and edge computing applications

Applications that use edge computing and 5G to improve response times consume both compute and network resources. However, 5G networks manage only network resources without considering the application’s compute requirements, and container orchestration frameworks manage only compute resources without considering the application’s network requirements. We observe that there is a complex coupling between an application’s compute and network usage, which can be leveraged to improve application performance and resource utilization. We propose a new, declarative abstraction called app slice that jointly considers the application’s compute and network requirements. This abstraction leverages container management systems to manage edge computing resources, and 5G network stacks to manage network resources, while the joint consideration of coupling between compute and network usage is explicitly managed by a new runtime system, which delivers the declarative semantics of the app slice. The runtime system also jointly manages the edge compute and network resource usage automatically across different edge computing environments and 5G networks by using two adaptive algorithms. We implement a complex, real-world, real-time monitoring application using the proposed app slice abstraction, and demonstrate on a private 5G/LTE testbed that the proposed runtime system significantly improves the application performance and resource usage when compared with the case where the coupling between the compute and network resource usage is ignored.
Adaptive Regularized Submodular Maximization.

In this paper, we study the problem of maximizing the difference between an adaptive submodular (revenue) function and an non-negative modular (cost) function under the adaptive setting. The input of our problem is a set of $n$ items, where each item has a particular state drawn from some known prior distribution $p$. The revenue function $g$ is defined over items and states, and the cost function $c$ is defined over items, i.e., each item has a fixed cost. The state of each item is unknown initially, one must select an item in order to observe its realized state. A policy $\pi$ specifies which item to pick next based on the observations made so far. Denote by $g_{avg}(\pi)$ the expected revenue of $\pi$ and let $c_{avg}(\pi)$ denote the expected cost of $\pi$. Our objective is to identify the best policy $\pi^o\in \arg\max_{\pi}g_{avg}(\pi)-c_{avg}(\pi)$ under a $k$-cardinality constraint. Since our objective function can take on both negative and positive values, the existing results of submodular maximization may not be applicable. To overcome this challenge, we develop a series of effective solutions with performance grantees. Let $\pi^o$ denote the optimal policy. For the case when $g$ is adaptive monotone and adaptive submodular, we develop an effective policy $\pi^l$ such that $g_{avg}(\pi^l) - c_{avg}(\pi^l) \geq (1-\frac{1}{e}-\epsilon)g_{avg}(\pi^o) - c_{avg}(\pi^o)$, using only $O(n\epsilon^{-2}\log \epsilon^{-1})$ value oracle queries. For the case when $g$ is adaptive submodular, we present a randomized policy $\pi^r$ such that $g_{avg}(\pi^r) - c_{avg}(\pi^r) \geq \frac{1}{e}g_{avg}(\pi^o) - c_{avg}(\pi^o)$.
Forward-looking persistent excitation in model predictive control

Abstract This work deals with the problem of integrating persistence of excitation into nonlinear constrained model predictive control to estimate uncertain parameters while guaranteeing a stable closed loop. We propose an adaptive tracking model predictive control and conditions which guarantee persistent excitation and uniformly bounded closed loop signals of nonlinear systems , despite bounded noise and parameter uncertainty. This is achieved by actively designing persistence of excitation through the computation of a reference trajectory around some nominal stationary point depending on the parameter estimate, opening up the opportunity of balancing excitation against other requirements. Appealing to the Total Stability Theorem, the results are local and solution evolves in a non-infinitesimal ball in state and estimated parameter.
The Impact of Leakages from 401(k)s and IRAs

This paper summarizes what is known about leakages from existing studies and relates these results to detailed data on leakages in 2013 provided by Vanguards How America Saves. It then uses two data sets  the Survey of Consumer Finances (SCF) and the Survey of Income and Program Participation (SIPP)  to estimate the impact of leakages on wealth at retirement. The Vanguard data are a critical component because they provide a comprehensive picture of assets and participant flows, whereas the surveys on which earlier studies were based tended to focus on one component, such as loans. A key limitation is that Vanguards population is probably older and wealthier than the general population. The paper found that: *About 1.5 percent of assets leak out of the 401(k)/IRA system each year. *Of the different forms of leakages, in-service withdrawals and cashouts appear to represent the most significant source of leakages, while loans created a measurable but relatively small leakage. *Based on our estimates, aggregate 401(k) and IRA retirement wealth is at least 20 percent lower than it would have been without current leakage rules. The policy implications of the findings are: *Hardship withdrawals could be limited to serious, unpredictable hardships and the amounts distributed not subject to the 10-percent penalty. *The age for non-penalized withdrawals from both 401(k) and IRAs could be raised to at least Social Securitys Earliest Eligibility Age, which is currently 62. *The cash-out mechanism could be closed down entirely, by changing the law to prohibit lump-sum distributions upon termination.
A Graph-Theoretic Approach to Randomization Tests of Causal Effects Under General Interference

Interference exists when a unit's outcome depends on another unit's treatment assignment. For example, intensive policing on one street could have a spillover effect on neighboring streets. Classical randomization tests typically break down in this setting because many null hypotheses of interest are no longer sharp under interference. A promising alternative is to instead construct a conditional randomization test on a subset of units and assignments for which a given null hypothesis is sharp. Finding these subsets is challenging, however, and existing methods are limited to special cases or have limited power. In this paper, we propose valid and easy-to-implement randomization tests for a general class of null hypotheses under arbitrary interference between units. Our key idea is to represent the hypothesis of interest as a bipartite graph between units and assignments, and to find an appropriate biclique of this graph. Importantly, the null hypothesis is sharp within this biclique, enabling conditional randomization-based tests. We also connect the size of the biclique to statistical power. Moreover, we can apply off-the-shelf graph clustering methods to find such bicliques efficiently and at scale. We illustrate our approach in settings with clustered interference and show advantages over methods designed specifically for that setting. We then apply our method to a large-scale policing experiment in Medellin, Colombia, where interference has a spatial structure.
The Control of Corporal Smooth Muscle Tone, the Coordination of Penile Erection, and the Etiology of Erectile Dysfunction: The Devil is in the Details

Penile erection is a complex neurovascular event with hemodynamic features analogous to those observed in vascular tissues throughout the vascular tree. A spate of recent basic research activity into the mechanistic basis for the control of penile erection and the etiology of erectile dysfunction has highlighted the central role of the corporal smooth muscle cell in this process. It is now clear that penile erection is highly dependent not only on the integrity of the corporal smooth muscle cells that comprise the vast majority of the corporal parenchyma, but also on their ability to respond to stimuli for both contraction and relaxation in a coordinated and syncytial fashion. As such, further elaboration of the precise mechanistic details concerning the physiology and pathophysiology of the control of corporal smooth muscle tone represents the greatest remaining barrier to the improved understanding, diagnosis, and treatment of erectile dysfunction. It is anticipated that multidisciplinary basic research...
Ion Detection in Mass Spectrometry

A review of the principles of ion detect is discussed. These principles include secondary electron emission, analog and pulse-counting detection, basic and advanced detector designs. In addition,factors that influence the detection of molecular ions of biomolecules, as well as some of the methods that have been employed to improve detection efficiency of these large ions, are described.
Bio-organic reaction animations (BioORA): Student performance, student perceptions, and instructor feedback

Research shows that computer animations are especially helpful in fields such as chemistry and in this mixed-methods study, we investigate the educational effectiveness of Bio-Organic Reaction Animations (BioORA), a 3-D software, in four undergraduate biochemistry classes at different universities. Statistically significant findings indicate that students performed better on a quiz completed after a lesson with BioORA than after a lesson with regular teaching methods in three out of four classes. Ratings on several survey items completed after experiencing BioORA, including items related to interest, value, and ability, were higher in two classes. Surveys and one-on-one interviews reveal instructor and student experiences with the software as well as the utility of various software features, which can be adopted in other programs. Instructors and students provide suggestions to maximize BioORA's benefits as an educational tool and findings suggest the importance of multiple forms of information to enhance student understanding and reach students with various learning preferences.
A Genetic Algorithm and Tabu Search for discovering regular plans in mobile clients

In a mobile computing system, broadcasting has become one of the most interesting and challenging research issue. The server continuously broadcasts data to mobile users. The data can be inserted into customized size relations and broadcasted as Regular Broadcast Plan (RBP) with multiple channels. Two algorithms, the Basic Regular (BRA) and the Partition Value Algorithm (PVA), can provide a static and dynamic RBP construction with multiple constraints solutions respectively. Servers have to work with many broadcasting plan operations. The operations become more complicated when there are many kinds of services. A Hybrid Genetic Algorithm using Tabu Search (GTS) for the local minimum is developed. The GTS can discover RBPs with the minimum number of channels. In addition, with the move operations it can also discover more than one RBPs with minimum number of channels including different composition RBPs. A set of criteria are introduced that enhance the Tabu search part of GTS for discovering RBPs. Theorems can provide direct conditions that can state the existence of the necessary criteria of having RBP and RBPs with different composition without considering those criteria. From all the above modern servers can be upgraded in regards to RBPs discovery with fewer channels.
Human Notch-1 Inhibits NF-κB Activity in the Nucleus Through a Direct Interaction Involving a Novel Domain

Notch participates in diverse cell fate decisions throughout embryonic development and postnatal life. Members of the NF-κB/Rel family of transcription factors are involved in the regulation of a variety of genes important for immune function. The biological activity of the NF-κB transcription factors is controlled by IκB proteins. Our previous work demonstrated that an intracellular, constitutively active form of human Notch-1/translocation-associated Notch homologue-1 (NotchIC) functions as an IκB molecule with specificity for the NF-κB p50 subunit and physically interacts with NF-κB in T cells. In the current study, we investigated the roles of different domains of NotchIC in the regulation of NF-κB-directed gene expression and NF-κB DNA binding activity. We found that NotchIC localizes to the nucleus and that a region in the N-terminal portion of NotchIC, not the six ankyrin repeats, is responsible for the inhibitory effects of Notch on NF-κB-directed gene expression and NF-κB DNA binding activity. The N-terminal portion of NotchIC inhibited p50 DNA binding and interacted specifically with p50 subunit, not p65 of NF-κB. The interaction between Notch and NF-κB indicates that in addition to its role in the development of the immune system, Notch-1 may also have critical functions in the immune response, inflammation, viral infection, and apoptosis through control of NF-κB-mediated gene expression.
Spectrum-Dependent Spiro-OMeTAD Oxidization Mechanism in Perovskite Solar Cells.

We propose a spectrum-dependent mechanism for the oxidation of 2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenylamine)-9,9′-spirobifluorene (Spiro-OMeTAD) with bis(trifluoromethane)sulfonimide lithium salt (LiTFSI), which is commonly used in perovskite solar cells as the hole transport layer. The perovskite layer plays different roles in the Spiro-OMeTAD oxidization for various spectral ranges. The effect of oxidized Spiro-OMeTAD on the solar cell performance was observed and characterized. With the initial long-wavelength illumination (>450 nm), the charge recombination at the TiO2/Spiro-OMeTAD interface was increased due to the higher amount of the oxidized Spiro-OMeTAD. On the other hand, the increased conductivity of the Spiro-OMeTAD layer and enhanced charge transfer at the Au/Spiro-OMeTAD interface facilitated the solar cell performance.
Meta-Analytic Benefit Transfer of Outdoor Recreation Economic Values: Testing Out-of-Sample Convergent Validity

A benefit transfer approach to recreationeconomic valuation using meta-analysis isexamined. Since the meta- regression modeltakes into account some of the study specificeffects on willingness to pay (WTP) estimates,benefit transfer using meta-analysis couldyield a valid WTP estimate of unstudiedrecreation resources. The convergent validityof the meta-analytic benefit transfer is testedusing out-of-sample original studies from theU.S. The analyses are performed usingpercentage difference, paired t-test,regression and correlation tests. The testsreveal mixed results on convergence betweenestimated WTP using meta-analytic benefittransfer function (BTF) and out-of-sampleoriginal WTP values. There is a fairly highpercentage difference between the estimated andoriginal WTP values (80–88%), and the meandifferences are statistically significant asshown by paired t-tests. However, correlationand regression results consistently showsignificant positive relationships betweennational BTF estimated and original WTP valuesindicating some level of convergence. Theresults show that the national BTF outperformthe regional BTF indicating a potential of thenational BTF for recreation benefit transferwhen a “first best” primary valuation study isnot affordable.
Macrocyclic poly(methyl acrylate) and macrocyclic poly(methyl acrylate-block-styrene) synthesized by radical trap-assisted atom transfer radical coupling

Abstract Dibrominated poly(methyl acrylate) (BrPMABr) was prepared by atom transfer radical polymerization (ATRP), and this unpurified reaction mixture was used directly in a radical trap-assisted atom transfer radical coupling (RTA-ATRC) reaction to achieve cyclic PMA by intramolecular chain-end coupling. When the polymerization-to-cyclization crossover was performed as a one pot-two step sequence simply by the addition of the radical trap 2-methyl-2-nitrosopropane (MNP) and increased amounts of ligand-catalyst complex, cyclic PMA could be formed in yields up to 65% by adjusting the total volume and reactant ratios during the intramolecular RTA-ATRC, based on gel permeation chromatography (GPC) analysis. In analogous intramolecular ATRC trials lacking the radical trap, cyclization was not successful and instead chain extension by continuation of ATRP was observed. When the ATRP reaction mixture containing the BrPMABr precursor was added drop-wise into a redox active solution containing MNP, yields of cyclic polymer were increased up to 85%. The effect of the ligand was studied, with the highest amounts of cyclic product obtained in intramolecular RTA-ATRC reactions using tris[2-(dimethylamino)ethyl]amine (Me 6 TREN) as the ligand. Cyclic diblock copolymers were also prepared by this method, using telechelic poly(methyl acrylate- block -styrene- block -methyl acrylate) (PMA-b-PS-b-PMA) linear precursors prepared by sequential ATRP reactions.
Azaserine: survival and mutation in Escherichia coli

Azaserine in an antineoplastic agent, mutagen and carcinogen that is known to inhibit purine metabolism. Comparison of mutation in stationary-phase cultures of E. coli WP2 and a series of its DNA repair-deficient mutants exposed to azaserine showed that the effects of the compound closely mimicked those caused by UV light indicating, therefore, that azaserine-induced mutagenesis occurred via pathways dependent upon the recA and lexA genes. Comparison of survival of these strains showed that potentially lethal DNA lesions induced by azaserine were corrected by the excision, recombination, and rec-lex repair systems. These results show that azaserine causes DNa damage as well as inhibition of purine metabolism.
From Buckingham palace to southfork ranch: The case for a structuralist view of popular culture

The structuralist approach first developed by Levi‐Strauss for myth analysis has been applied by others to such varied genre as historical myth, religious writings, and literary classics. This paper presents the case for a structuralist view of popular culture. The popular history of Britain's Windsor monarchy and the plot of the television serial “Dallas” are discussed as examples of the negation and mediation patterns, respectively. This analysis of “factual” history alongside a “fictional” plot demonstrates that history is a relative interpretation of events and that beneath apparently dissimilar phenomena the same underlying structure may be discovered.
Responsiveness of the Pelvic Floor Distress Inventory (PFDI) and Pelvic Floor Impact Questionnaire (PFIQ) in women undergoing vaginal surgery and pessary treatment for pelvic organ prolapse.

Objective This study was undertaken to evaluate the responsiveness of the Pelvic Floor Distress Inventory (PFDI) and Pelvic Floor Impact Questionnaire (PFIQ) in women with pelvic organ prolapse undergoing surgical and nonsurgical management. Study design The responsiveness of the prolapse, urinary and colorectal scales of the PFDI and PFIQ were assessed in 2 independent populations: (1) 42 women with stage II or greater prolapse enrolled in an ongoing multicenter randomized trial comparing 2 different pessaries (Pessary group) and (2) 64 women with stage III or greater prolapse who underwent vaginal reconstructive surgery (Surgery group). All subjects completed the PFDI and PFIQ at baseline and again either 3 months (Pessary group) or 6 months (Surgery group) after initiation of treatment. Responsiveness was assessed with standardized response mean (SRM), effect size (ES), and the paired t test. Results In the Pessary group, there was a significant improvement in the prolapse and urinary scales of the PFDI, with each demonstrating moderate responsiveness (prolapse: SRM 0.69, ES 0.68; urinary: SRM 0.57, ES: 0.50, P P P Conclusion The PFDI and PFIQ are responsive to change in women undergoing surgical and nonsurgical treatment for pelvic organ prolapse. The PFDI is more responsive than the PFIQ.
Membrane-Associated Vitamin D-Induced Calcium-Binding Protein (CaBP): Quantification by a Radioimmunoassay and Evidence for a Specific CaBP in Purified Intestinal Brush Borders*

The vitamin D-induced intestinal calcium-binding protein (CaBP) was quantitated in membranous components of the intestinal mucosa by a specific and sensitive RIA. Inclusion of detergent (Triton X-100) in extraction buffer and in the RIA system was required to release and measure membraneassociated CaBP. Purified brush borders were shown to contain CaBP with a specific activity (micrograms per mg protein) about 12% of that in the total homogenate. By transferring proteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to nitrocellulose blots electrophoretically, CaBP was immunologically detected in brush borders from vitamin D3-treated chicks, but not in those from vitamin D3-deficient chicks. CaBP was also detected in isolated brush border membrane vesicles by the gel electrophoresis-blot transfer technique. Brush border CaBP was inaccessible to proteolytic hydrolysis by trypsin unless trypsinized in the presence of detergent. CaBP-binding substances were found to be present in pur...
The compressive viscoplastic response of an A359/SiCp metal-matrix composite and of the A359 aluminum alloy matrix

Abstract The mechanical behaviors of an A359/SiCp metal–matrix composite and of the corresponding A359 cast aluminum alloy have been measured in compression over a wide range of strain rates (10–4–105 s–1) using several different experimental techniques: servohydraulic testing, the compression Kolsky bar, and pressure–shear plate impact. Both the A359 matrix alloy and the A359/SiCp composite show rate dependence of the flow stress in compression, with rate dependences that increase with increasing strain rate. The unreinforced A359 alloy shows strain hardening that is essentially independent of the strain rate, and similar in most respects to the behavior of wrought aluminum alloys such as 6061. The A359/SiCp composite shows rate dependence similar to that of the unreinforced alloy, but also shows significantly less strain hardening than does the matrix alloy. This reduction in strain hardening appears to be a result of progressive particle fracture during these compressive deformations. Using the experimental data on the unreinforced A359 aluminum alloy as the input data for the matrix behavior, and accounting for particle shape and aspect ratio, an analytical model developed recently by the authors is used to estimate the mechanical response of the composite over the whole range of strain rates. The model is able to capture the rate dependence of the flow stress of the composite, and is able to provide a reasonable estimate of the flow stress of the composite material at small strains. However, because the model does not incorporate the particle damage that occurs in the composite, it is unable to predict the changed overall strain hardening of the composite material.
Second-harmonic generation of nonlinear optical crystals in vacuum-ultraviolet and x-ray regions.

In spite of high absorption, nonlinear optical crystals have a high nonlinear susceptibility in the vacuum-ultraviolet and the x-ray regions, providing a basis for second-harmonic generation. In the conventional transmission configuration, a crystal film \ensuremath{\sim}100 \AA{} thick may generate sufficiently strong second harmonics with a few tenths conversion efficiency under a double-resonance condition. The phase-matching restriction is almost lifted, as a result of the tiny thickness. However, the reflection configuration is shown to be unique and promising under the double-resonance condition. The conversion efficiency may also reach a few tenths, while the crystals need not be thin films, and the problem of heat dissipation is relieved.
State Limitations, Self-Help Secondary Schooling, and Development in Kenya

Theories of Third World education offer different views on the role and strength of the state, and several scholars argue that Third World states are too weak and 'fragile" to implement development programs for education, health, and other areas. This case study of Kenya examines the national education structure and its relationship to different types of development. The analysis (based on detailed district-level data) shows that government-sponsored education is not extensive enough to affect comprehensive national development. By contrast, nongovernment "self-help" secondary education is strongly associated with lower child mortality and other types of development. Local communities pool their financial and labor resources to build and operate secondary schools, efforts that are sometimes organized around ethnicity. However, self-help efforts are not as effective in eradicating tropical disease or other serious health problems, which require substantial technology and.financial resources.
Direct affinity screening chromatography–mass spectrometry assay for identification of antibacterial agents from natural product sources

Abstract A direct affinity screening – mass spectrometry assay, coupled to liquid chromatography, is presented as a tool for natural product drug discovery. Using the assay, fractionated extracts from a Caribbean gorgonian coral were shown to contain a new chemical entity (NCE) which binds to a mimic of the Gram positive bacterial cell wall (lysine– d -alanine– d -alanine). Conditions for observation of a specific noncovalent complex between the NCE and the target mimic using electrospray ionization-mass spectrometry were validated in a series of positive and negative control experiments, which featured flow injection analysis-based titrations. While the structural identity of the NCE could not be determined due to limited sample quantities, this work provides proof-of-principle for such an approach to potentially accelerate drug discovery from natural product sources.
Emergency Physicians' Perspectives on Smallpox Vaccination

Objective: To evaluate emergency physician (EP) attitudes toward smallpox vaccination, the treatment of patients with suspected smallpox, and the threat of a bioterrorist attack. Methods: This was a prospective study utilizing a standardized survey instrument that was distributed on November 16, 2002, and collected by February 1, 2003. EPs from a sample of 50 accredited emergency medicine programs were surveyed regarding their perspectives on smallpox vaccination. Results: A total of 989 surveys were collected from 42 emergency medicine programs. Of the respondents, 43.4% would currently volunteer for smallpox vaccination. EPs previously vaccinated against smallpox were 1.46 times more likely to volunteer for vaccination (95% CI = 1.14 to 1.93). EPs who believed they were at risk for complications were less than half as likely to volunteer for vaccination. EPs who perceived a significant risk of a bioterrorist attack were 2.7 times more likely to volunteer for the vaccine compared with those who thought the risk was minimal (95% CI = 2.06 to 3.47). Of the respondents, 34.4% believed the risks of the vaccination outweighed the benefits, 33% did not, and 32.6% were unsure. Conclusions: Currently, fewer than half of EPs surveyed would volunteer for smallpox vaccination. Factors associated with a willingness to be vaccinated include previous smallpox vaccination and the perceived threat of a bioterrorist attack. The variation in EP attitudes toward smallpox vaccination may be due to uncertain risk-to-benefit ratio. The opinions and actions of EPs may be influential on current and future government policy and public opinion.
A simple crab‐like cyclization procedure to prepare polyaza‐crowns and cyclams with one or two unsubstituted macroring nitrogen atoms or with a hydroxy group

A simple and convenient method to prepare polyaza-crowns and cyclams containing one or two unsubstituted macroring nitrogen atoms or a hydroxy group is described. The process involves the reaction of a bis- chloroamide with a bis-secondary amine followed by reduction of the cyclic diamide. The bis-chloroamide resembles a crab with two reactive organochloride groups poised and ready to react, hence the term “crab-like” cyclization. Nine new polyaza-crowns and cyclams were prepared.
B-cell receptor cross-linking delays activation-induced cytidine deaminase induction and inhibits class-switch recombination to IgE.

Background During differentiation, B cells receive signals by antigen through the B-cell receptor (BCR) and signals that induce isotype switching. Objective We sought to investigate the effects of BCR ligation on isotype switching. Methods Naive B cells from BALB/c mice were stimulated with LPS plus IL-4 alone or plus anti-IgM (0.1-10 μg/mL). IgE and IgG1 levels in supernatants were measured by means of ELISA on day 6. Cμ or Cɛ germline transcripts, activation-induced cytidine deaminase (AID), and Iμ-Cɛ postswitch transcripts were measured by means of RT-PCR. Deletional switch recombination was assessed by means of digestion circularization PCR of Sμ-Sɛ products. Results BCR cross-linking inhibited IgE and IgG1 switching in a dose-dependent fashion. This was not due to inhibition of proliferation, increased apoptosis, or cell death. BCR cross-linking had no effect on Cμ or Cɛ germline transcripts but suppressed the generation of Sμ-Sɛ switch products and Iμ-Cɛ postswitch transcripts and caused a delay in the expression of AID mRNA, with decreased expression on days 2 and 3 after stimulation. Concomitantly, the number of DNA repair foci at the IgH locus on day 3 was significantly decreased. AID expression and activity became normal on day 4, but isotype switching remained profoundly diminished 8 days after stimulation. Conclusion BCR cross-linking delays AID expression. This might interfere with class-switch recombination by disrupting the temporal coordination of signals that lead to class-switch recombination.
Interactions between fungal growth, substrate utilization, and enzyme production during solid substrate cultivation of Phanerochaete chrysosporium on cotton stalks.

Fungal pretreatment, using lignin-degrading microorganisms to improve lignocellulosic feedstocks with minimal energy input, is a potential alternative to physiochemical pretreatment methods. Identifying the kinetics for fungal pretreatment during solid substrate cultivation is needed to help establish the processing conditions for effective scale up of this technology. In this study, a set of mathematical models were proposed for describing the interactions between holocellulose consumption, lignin degradation, cellulase, ligninolytic enzyme, and the growth of Phanerochaete chrysosporium during a 14 day fungal pretreatment process. Model parameters were estimated and validated by the System Biology Toolbox in MatLab. Developed models provided sufficiently accurate predictions for fungal growth (R 2 = 0.97), holocellulose consumption (R 2 = 0.97), lignin degradation (R 2 = 0.93) and ligninolytic enzyme production (R 2 = 0.92), and fair prediction for cellulase production (R 2 = 0.61). The models provide valuable information for understanding the interactive mechanisms in biological systems as well as for fungal pretreatment process scale up and improvement.
Assessing Capabilities in International Politics: Biased Overestimation and the Case of the Imaginary ‘Missile Gap’

Abstract How states assess the capabilities of their adversaries and rivals is of paramount importance to the theory and practice of international relations. This paper presents a framework for understanding why states overestimate the capabilities of their adversaries. Three types of overestimation are presented, consisting of conscious/rational, erroneous and biased overestimation. In order to demonstrate the phenomenon of biased overestimation in international politics, the case of the ‘Missile Gap’ (1957–61) controversy in the United States is examined.
Oxygen delivery to the brain before and after birth

We studied the relationship between cerebral oxygen consumption and cerebral oxygen delivery (cerebral blood flow x arterial oxygen content) in fetal, newborn, and adult sheep, Relative to the amount of oxygen consumed, cerebral oxygen delivery in the fetus exceeds that in the lamb and adult by 70 percent. This may represent a protective advantage for the fetus or simply a necessary adaptation to the low arterial oxygen pressure in the intrauterine environment.
Soluble Alkyl-Substituted Poly(ethylenedioxythiophenes) as Electrochromic Materials

It is shown that the oxidative solution polymerization of 2-tetradecylthieno[3,4-b]-1,4-dioxin results in soluble polymers with optical and redox properties similar to those of electrochemically prapared insoluble films
Osteophagia and bone modifications by giraffe and other large ungulates

Ungulates often gnaw on animal bones, antlers, horns, and ivory in order to maintain certain nutritional requirements. The resulting modifications to bones and other skeletal elements have been variously described and reported, but are largely absent from most taphonomic reference works. Previous accounts of such gnawing behaviors have been restricted to smaller ungulates. Here we provide detailed description of large ungulates gnawing on bones from similarly sized animals, namely giraffe, camel, and cattle, from Africa, Australia, and North America. Large ungulates will often select fresh bones for gnawing, but will also target dry and weathered bones. Surface modifications are variable, ranging from tooth depressions, punctures, and grooves, to scooping out damage, polishing, and splintering. Similar features are prevalent in carnivore- and porcupine-gnawed bone assemblages, but the effects of large ungulate gnawing can be readily distinguished from those taphonomic agents. Ungulate gnawing may also vary in relation to body size, in that smaller ungulates impact skeletal elements differently than larger ungulates.
Probabilistic modelling of distribution harmonics: data collection and analysis

Abstract Numerous nonlinear loads on the distribution system distort currents and voltages. Exact penetration, time of operation, etc. of these loads are non-deterministic. Therefore, harmonics at a distribution node (branch) should be viewed as a stochastic process. This paper presents a technique, based on statistical tests, which can be used to derive a probabilistic model for harmonics. This technique can be used to assess impacts of harmonics. An example demonstrates the application of the proposed method. The methodology consists of the following two tests: (1) a non-parametric run test to establish stationarity of a data set, and (2) chi-squared goodness-of-fit, another non-parametric test, to establish normality of the data set.
Binding characteristics of t-[35S]butylbicyclophosphorothionate in discrete brain regions of rats made tolerant to and dependent on pentobarbital.

: The effects of acute and continuous pentobarbital administration by pellet implantation on binding characteristics of t-[35S]butylbicyclophosphorothionate ([35S]TBPS) in discrete regions of rat brains were examined. Acute administration of pentobarbital (60 mg/kg, s.c.) affected neither the KD nor the Bmax values of [35S]TBPS binding in any of the regions studied. The cerebella of pentobarbital-tolerant rats had an increased density of [35S]TBPS binding sites with no change in their apparent affinity. There were no significant changes in the binding characteristics in the frontal cortex (FC), the striatum (ST), and the substantia nigra (SN) of these animals. Twenty-four hours after removal of the pentobarbital pellets, a significant decrease in the latency of onset of first twitch response induced by pentylenetetrazol (PTZ) (50 mg/ kg, i.p.) was observed. In addition, the density of [35S]TBPS binding sites was significantly increased in the FC, the SN, and the cerebellum but not in the ST. In all brain regions studied, placebo pellet implantation and pentobarbital tolerance and dependence caused no changes in the apparent affinity of [35S]TBPS binding or the IC50 of pentobarbital for the inhibition of [35S]TBPS binding. These results suggest that [35S]TBPS binding was significantly increased following the withdrawal of the pentobarbital pellets without altering intrinsic coupling activity of barbiturate recognition sites and convulsant binding sites and that these increases in [35S]TBPS binding are related to the increased susceptibility to seizures induced by PTZ in rats made dependent on pentobarbital.
Rhetoric and Reality? Unilateralism and the Obama Administration

Objectives The objectives of this article are to examine the concept of presidential unilateralism in the Obama administration. The research to date suggests that unilateralism in a presidency occurs once the political conditions for a president become unstable—drop in public opinion, loss of congressional support, etc. This article argues that the Obama administration came to office with the assumption that those conditions would naturally occur, thus began to prepare to act unilaterally from the outset. Methods This article uses official White House memoranda coupled with an examination of presidential signing statements to support the argument. Results President Obama made it difficult to track the use of the signing statement by discontinuing use of the Weekly Compilation of Presidential Documents in the first days of the administration as well as a redesign of the White House website to make it hard to determine which signing statements made constitutional challenges to provisions of law and which did not, all without drawing much attention from the public, the press, or the Congress. Conclusions Obama has governed very much like his predecessors, where acting unilaterally is concerned. He has continued to use the signing statement much like his predecessors with an eye toward keeping his actions hidden from public view.
The maximum potential energy of elastic rods under axial gravitational load

An optimal design problem solved previously for an elastic rod hanging under its own weight found the distribution of the cross-sectional area that minimized the total potential energy stored in an equilibrium state, with the admissible designs bounded above and below and also subject to the constraint of prescribed total volume. This work solves the companion problem of the design that stores the maximum potential energy under the same constraint conditions. The method used is based on a comparison theorem for sandwich structures.
Holographic stereograms as discrete imaging systems

Unlike holograms of real objects, holographic stereograms consist of information recorded from a relatively small number of discrete viewpoints. As discrete imaging systems, holographic stereograms are susceptible to aliasing artifacts caused by insufficient or improper sampling. A characterization of sampling-related image artifacts in holographic stereograms is presented. Constraints on image extent and resolution imposed by sampling are outlined. Methods of reducing or eliminating aliasing artifacts in both photographically-recorded and computer-generated holographic stereogram images are described. Results of this analysis can be generalized to describe other autostereoscopic displays.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.