cssi/SciSciGPT-SciSciNet huggingface dataset:
Detailed effects of scattering and absorption by haze and aerosols in the atmosphere on the average point spread function of an imaging system

The Earth's atmosphere has significant effects on the propagation of electromagnetic (EM) radiation and accordingly degrades the performance of electro-optical systems. These effects are attributed to atmospheric turbulence and to absorption and scattering of EM waves by atmospheric molecules and aerosols. In this paper we develop a detailed model of the effects of absorption and scattering on the optical radiation propagating from the object plane to an imaging system based on the classical theory of EM scattering. Scattering has the effect of de-correlating the light leaving the target from the unscattered light reaching the imaging system, and scattering has the effect of broadening the angle at which the scattered light arrives at the receiver compared to the unscattered light. Absorption has the effect of reducing the amount of power available for the image. Both of these effects depend upon the atmospheric species present, their EM properties, and wavelength. We use this detailed model to compute the average point spread function (PSF) of an imaging system that properly accounts for the effects of the diffraction and scattering, and the appropriate optical power level of both the unscattered and the scattered radiation arriving at the pupil of the imaging system. Since the scattered radiation is temporally and spatially de-correlated from the unscattered radiation, we model the effects of the unscattered radiation and the radiation scattered from the various species as additive in the image plane. The key result of this study is the significant effect of atmospheric scattering on the contrast and spatial resolution of images acquired by imaging systems, due to the increased level of the scattered radiation PSF and the reduced level of the direct radiation PSF, upon increasing the atmospheric optical depth.
Monte Carlo Simulation of the Effect of Entanglements on the Swelling and Deformation Behavior of End-Linked Polymeric Networks

The effect of entanglements on deformation properties of end-linked networks was investigated using Monte Carlo simulations. Model tetrafunctional networks were prepared by cross-linking precursor monodisperse chains in the framework of the bond fluctuation model (BFM). The degree of entanglement in these networks was tuned by changing the precursor chain lengths (N = 20 and 50-mers) and the initial polymer concentration (Φ0). Continuum-space simulations of isotropic swelling and uniaxial deformation were carried out in isobaric and isostress ensembles, respectively. Both equilibrium swelling and force-strain data indicated that elastic forces are enhanced in more entangled networks. The effect of Φ0 on the equilibrium swelling and on the elastic modulus was analyzed with the help of scaling theory and the Rubinstein and Panyukov model, respectively; our results are shown to be consistent with reported experimental data. Our results indicate that the effect of entanglements on the network elastic response...
Tracing trace elements from sediment input to volcanic output at subduction zones

AT ocean trenches, sea-floor sediments may either be scraped off the subducting plate, or accompany it into the mantle. Some of the subducted sediment may then be recycled to the arc crust by magmatism1; the rest may be recycled into the mantle, and contribute to mantle heterogeneity2. Strong evidence for sediment contributions to arc volcanism has come from isotope tracers, such as 207Pb and 10Be (refs 3–5), but a global mass balance requires consideration of element fluxes6. Here we report the sedimentary fluxes into eight trenches around the globe of trace elements that are enriched in arc volcanics (Ba, Sr, K, Rb, Cs, La, Th and U)7 We show that the volcanic outputs clearly reflect the sediment inputs, once the effects of melting are taken into account8. Where the sediment flux into a trench is high for a particular element, the associated volcanics are enriched in this same element. Thus, some of the geochemical characteristics of arc volcanics can be traced back to the sediments at the trench. A mass balance of the inputs and outputs will ultimately provide estimates for how much sediment is recycled to the arc, and how much to the deeper mantle.
VERBAL INTERACTION DIFFERENCES BETWEEN JUNIOR/COMMUNITY COLLEGE AND UNIVERSITY SETTINGS

Experience with current instructional strategies employed throughout various educational institutions led the authors of the paper to question the general state of affairs portrayed by recent HEW statements concerning “abstract” knowledge imparted to “passive” students. A research design is given along with a data analysis. Findings are reported and future directions established.
Nonlinear transient response of imperfect hyperbolic shells using a reduction method

Abstract The paper analyzes the effect of geometric imperfections on the free-vibration, and static and dynamic responses of hyperbolic shells. The effect of geometric nonlinearities is included. A 48 degree-of-freedom thin shell element, capable of modeling arbitrary geometric imperfections, is employed. A reduced basis method using the normal modes as the base vectors is employed to reduce the size of the nonlinear problem and thus save computational effort. The resulting reduced (but still coupled) set of equations is integrated in a step-by-step fashion using the Wilson-θ method along with an iterative scheme. The integration scheme, first evaluated on a series of examples (both linear and nonlinear) is employed to obtain the dynamic response of hyperbolic shells with geometric imperfections. The shell is subjected to wind loads with an assumed time history. The results are presented for the nonlinear static response of a cooling tower under wind loads; for the fundamental frequencies of a hyperbolic shell under increasing axisymmetric pressure loads; and finally for the dynamic response (normal displacements and the in-plane stress resultants) of an example hyperbolic shell under dynamic wind loads. Whenever possible, the present results are compared with those available in the existing literature. A good agreement is observed.
TYROSINASE-CATALYZED OXIDATION OF 3,4-DIHYDROXYPHENYLGLYCINE

The oxidation chemistry of dopa in relation to melanin biosynthesis has been extensively studied. However, the oxidation of its lower homolog viz., 3,4-dihydroxyphenylglycine has not been described. Using 3,4-dimethoxybenzaldehyde as the starting material, the chemical synthesis of 3,4-dihydroxyphenylglycine was accomplished by Strecker's synthesis and demethylation reactions. Tyrosinase readily oxidized this unusual amino acid to the expected quinone. The glycyl-o-benzoquinone thus formed was highly unstable like its higher analog, dopaquinone. However, unlike its counterpart, it failed to exhibit intramolecular cyclization reaction. Rather, glycyl-o-benzoquinone exhibited facile transformation(s) to ultimately generate 3,4-dihydroxybenzaldehyde as an isolatable product. A probable mechanism involving intermediary formation of unstable quinone methide and carbinolamine intermediates is proposed to account for the novel transformation of glycyl-o-benzoquinone to 3,4-dihydroxybenzaldehyde.
Three adaptive discrete least squares cubic spline procedures for the compression of data

Abstract Three algorithms are developed for the compression of one-dimensional data by loosely coupled cubic splines. spline knots are located by adaptive iterative searches. The methods are applied to the compression of profile retrieval coefficients obtained from NOAA radiosonde/radiometric data. Additional compression is achieved by error acceptable, significant figure rounding, coupled with storage in integer strings. The results are compared with compression by finite-length discrete Fourier series computed by FFT procedures.
Biodiversity and Environmental Philosophy: An Introduction

Preface Acknowledgements 1. Introduction 2. Concerns for the environment 3. Intrinsic values and biocentrism 4. Tempered anthropocentrism 5. Problems of ecology 6. The consensus view of conservation biology 7. Incommensurability and uncertainty 8. Conclusion: issues for the future References Index.
An Asymptotic Expansion Approach to Modeling the Heat Transfer in a Reservoir-Extended Porous Slider Bearing

This work is a thermal simulation extension to the modeling of the fluid flow inside a reservoir-extended porous slider bearing [1]. The bearing system consists of a lubricating film, porous medium, and a reservoir. The velocity flow field generated by the modeling of the fluid flow is used as an input to solve the heat transfer problem. The small parameter used in the asymptotic expansion is the ratio of the reservoir depth to the length of the slider. The thermal effects upon the operation of this system are discussed.Copyright © 2008 by ASME
An experimental analysis of discriminability and bias in eye-gaze judgment

Following signal detection theory, the gazing of a videotaped confederate was judged by 12 subjects under four combinations of distance from the monitor and picture brightness. Separate measures of discriminability and judgment criterion, or bias, were derived. Eye gaze discriminability declined with both distance and brightness. Overestimation of the amount of eye gaze increased with distance and declining brightness, supporting Stephenson and Rutter's hypothesis that increased difficulty in discrimination will produce such a guessing bias.
Microarray analysis of thyroid hormone-induced changes in mRNA expression in the adult rat brain.

Abstract To determine which genes in the adult rat brain are regulated by thyroid hormone (TH), we used microarrays to examine the effect of hyperthyroidism on neuron-specific gene expression. Four-month-old male Fisher 344 rats were rendered hyperthyroid by intraperitoneal injection of 3,5,3′- l -triiodothyronine (T 3 , 15 μg/100 g body weight) for 10 consecutive days. To minimize interindividual variability, pooled cerebral tissue RNA from four-control and five-hyperthyroid rats was hybridized in duplicates to the Affymetrix (Santa Clara, CA) U34N rat neurobiology microarray, which contains probes for 1224 neural-specific genes. Changes in gene expression were considered significant only if they were observed in both pair-wise comparisons as well as by Northern blot analysis. Hyperthyroidism was associated with modest changes in the expression of only 11 genes. The expression of the phosphodiesterase Enpp2, myelin oligodendrocyte glycoprotein (Mog), microtubule-associated protein 2 (MAP2), growth hormone (GH), Ca 2+ /calmodulin-dependent protein kinase β-subunit (Camk2b), neuron-specific protein PEP-19 (Pcp4), a sodium-dependent neurotransmitter, and the myelin-associated glycoprotein (S-MAG) was significantly increased. Three genes were suppressed by hyperthyroidism, including the activity and neurotransmitter-induced early genes-1 and -7 (ANIA-1 and ANIA-7) and the guanine nucleotide-binding protein one (Gnb1). The present study underscores the paucity of TH responsive genes in adult cerebral tissue.
Competition between oxytetracycline and citrate for binding sites on hydroxyapatite crystals.

By exposing hydroxyapatite crystals of a regulated mesh size to increasing concentrations of citrate or oxytetracycline, it was possible to arrive at a constant saturation value for the ratio of ligand to calcium of hydroxyapatite in the resultant solid phase. When both ligands were present in a single solution, each reduced the amount of the other that was bound per unit quantity of calcium of the hydroxyapatite. A column chromatographic separation of citrate from oxytetracycline that permitted quantitative determination of citrate when both are present in a solution is described in this communication.
Inheritance of hexose 6-phosphate dehydrogenase polymorphism in brook trout

Electrophoretic analysis reveals two alleles, HpdJuicey,s-1, for the H6PD gene in brook trout from Newfoundland, with the HpdBanff-1 allele predominant. In contrast, the population from Brotkork Lake, Quebec, possesses five alleles for H6PD, including HpdBanff-1 and HpdJuicey's-1. The additional alleles are designated HpdBrotkork-1, HpdBrotkork-2, and HpdBrotkork-3. The description of these variants brings to seven the number of known alleles for the H6PD gene in brook trout from Canadian waters. Evidence indicates that H6PD is inherited tetrasomically in the Brotkork population, while in the hatchery population from Banff (Stegeman and Goldberg, 1971) this enzyme may be disomically inherited. We suggest that the difference between the two populations can be explained either by the occurrence of a Robertsonian fusion event or by the loss of duplicated copies of the H6PD gene in the population from which the Banff hatchery stocks were drawn.
DiGeorge syndrome: long-term survival complicated by Graves disease.

I. Brown HW: Congenital structural muscle anomalies. In Allen JH, editor: Strabismus Ophthalmic Symposium. 1. St. Louis, 1950, CV Mosby, pp 205. 2. Mein J: Superior oblique tendon sheath syndrome. Br Orthop J 28:70, 1971. 3. Rayner J, Hiatt RL: Bilateral Brown's superior oblique tendon sheath syndrome. Ann Ophthalmol 5:506, 1970. 4. Goldhammer Y, Smith JL: Acquired intermittent Brown's syndrome. Neurology 24:666, 1976. 5. Stein R: Posttraumatische intermittierence Pseudoparese des Musculus obliquus inferior. Mbl Augenheilkl 147:712, 1965. 6. Sims J: Acquired apparent superior oblique tendon sheath syndrome. Br Orthop J 28:112, 1971. 7. Clark E: A case of apparent intermittent overaction of the left superior oblique. Br Orthop J 23:116, 1966. 8: Sanford-Smith JH: Intermittent superior oblique tendon sheath syndrome. Br J Ophthalmol 53:412, 1969. 9. Killian P J, McClain B, Lawless O J: An unusual manifestation of rheumatoid arthritis. Arthritis Rheum 20:1080, 1977.
Improving the accuracy of finite difference methods for solving boundary value ordinary differential equations

It is shown that by introducing one or three interpolated values in each subinterval the local truncation error of finite difference (box, gap and deferred correction) methods can be decreased by two to four orders of magnitude when solving two point boundary value ordinary differential equations.
What Influences Principals' Perceptions of Academic Climate? A Nationally Representative Study of the Direct Effects of Perception on Climate

Using a nationally representative sample of public high schools (N = 439), we examined the extent to which the principal's perception of their influence over instruction, the evaluation of nonacademic related tasks as well as academic related tasks, and their relationship with the school district relates to their perception of academic climate while controlling for school-level covariates. Little attention has been given to date to the principal's perception of their responsibilities and how it relates to their view of academic climate. The findings link academic climate with direct effects from principal perceptions of support and evaluation from the district.
Testing an inference of function from structure: snake vertebrae do the twist.

The zygapophyses and zygosphene-zygantrum articulations of snake vertebrae are hypothesized to restrict or eliminate vertebral torsion. This hypothesis is apparently based solely on the inference of function from structure, despite the limitations of such inferences, as well as contradictory observations and measurements. In this study, I observed and measured axial torsion in gopher snakes, Pituophis melanoleucus. To examine the structural basis of axial torsion, I measured the vertebral articulation angles along the body and the insertion angles of five epaxial muscles. To examine torsion in a natural behavior, I digitized video images and measured the degree of appar- ent axial torsion during terrestrial lateral undulation. Finally, I measured the mechanical capacity of the vertebral joints for actual torsion over intervals of 10 vertebrae in fresh, skinned segments of the trunk. Vertebral articulation angles vary up to 30° and are associated with variation in torsional capacity along the trunk. The freely crawling P. melanoleucus twisted up to 2.19° per vertebra, which produced substantial overall torsion when added over several vertebrae. The vertebral joints are mechanically capable of torsion up to 2.89° per joint. Therefore, despite the mechanical restriction imposed by the com- plex articulations, vertebral torsion occurs in snakes and appears to be functionally important in several natural behaviors. Even in cases in which mechanical function appears to be narrowly constrained by morphology, specific functions should not be inferred solely from structural analyses. J. Morphol. 241:217-225, 1999. r 1999 Wiley-Liss, Inc.
Percutaneous Closure of Perivalvular Mitral Regurgitation: How Should the Interventionalists and the Echocardiographers Communicate?

There is considerable interest in percutaneous closure of perivalvular leaks without the need for repeat surgery. Successful percutaneous closure of these defects requires extensive planning and coordination before and during the procedure. However, there is no standardized description of valve pathology in the presence of a prosthetic valve, which adds to the challenge of communication. Transesophageal echocardiography is ideally suited to guide percutaneous mitral valve procedures, because of the proximity of the mitral valve to the esophagus. Successful percutaneous procedures of the mitral valve require teamwork. Both the interventionalist and the echocardiographer must have great familiarity with mitral valve anatomy, structure, and function, and they must know how to effectively communicate with each other. The authors review the relevant periprocedural mapping of the mitral valve and provide guidance to echocardiographers and interventionalists on effective ways to communicate during percutaneous perivalvular mitral leak closures to accomplish a successful outcome.
Probing Protein Ligand Interactions by Automated Hydrogen/Deuterium Exchange Mass Spectrometry

Amide hydrogen/deuterium exchange is a powerful biophysical technique for probing changes in protein dynamics induced by ligand interaction. The inherent low throughput of the technology has limited its impact on drug screening and lead optimization. Automation increases the throughput of H/D exchange to make it compatible with drug discovery efforts. Here we describe the first fully automated H/D exchange system that provides highly reproducible H/D exchange kinetics from 130 ms to 24 h. Throughput is maximized by parallel sample processing, and the system can run H/D exchange assays in triplicate without user intervention. We demonstrate the utility of this system to differentiate structural perturbations in the ligand-binding domain (LBD) of the nuclear receptor PPARγ induced upon binding a full agonist and a partial agonist. PPARγ is the target of glitazones, drugs used for treatment of insulin resistance associated with type II diabetes. Recently it has been shown that partial agonists of PPARγ have ...
Preoperative hydronephrosis as an indicator of survival after radical cystectomy

Abstract Objective We determined the prognostic significance of preoperative hydronephrosis in patients with transitional cell carcinoma (TCC) of the bladder undergoing radical cystectomy. Materials and Methods We performed a retrospective review of all patients undergoing radical cystectomy at a single institution from 1996 to 2006. Exclusion criteria included diagnosis other than TCC, upper tract TCC, incomplete medical records, or obstructing stones. Hydronephrosis was confirmed by radiographic imaging. Survival was determined by date of death or last clinic visit. Results Three hundred eight patients fulfilled the inclusion criteria; 203 (66%) had normal upper tracts, 82 (27%) had unilateral hydronephrosis, and 23 (7%) had bilateral hydronephrosis. Median overall survival of the study population was 34.3 months. There was a statistically significant difference in median survival between those without hydronephrosis (46.3 months), and those with unilateral (18.6 months, P = 0.004) or bilateral (13.4 months, P Conclusions Preoperative hydronephrosis is an important and independent prognostic variable in patients with TCC of the bladder treated with radical cystectomy.
The enlarging clinical spectrum of Lyme disease: Lyme cerebral vasculitis, a new disease entity.

The case of a patient with cerenral vasculitis with a right thalamic infarct associated with cerebral spinal fluid Lyme disease is presented. This entity has not been described in the United States, and only one similar case in the world literature could be found. The patient presented with a progressive headache and subsequent development of grand mal seizure activity. Lyme disease has been associated with cranial nerve palsies, peripheral and cranial radiculopathies, aseptic meningitis, encephalitic symptoms, chorea, and demyelinating polyneuropathy presenting like Guillain-Barre syndrome. These symdromes can occur separately or in combination. Stroke and strokeline syndromes have been attributed to Lyme disease. The literature concerning the neurologic manifestations of Lyme disease is reviewed.
Specificity and association constants of 33 monoclonal antibodies to human IgA epitopes.

Abstract We used an immunofluorescent sequential-saturation-of-antibody assay and an interactive computer program for Scatchard analysis to determine association constants ( K a ) of 33 murine monoclonal antibodies (Mabs) specific for human IgA epitopes. K a ranged from 0.37 to 690 × 10 7 liters per mole (an approximate 1900-fold difference). Specificity was validated with a panel of 18 highly purified IgA1 and IgA2 myeloma proteins and secretory IgA using an immunofluorometric assay. Western blots of bacterial IgA protease digests were used to locate the epitopes of IgA specific Mabs in either the Fab, Fc, or hinge region. Mabs specific for unique epitopes on secretory IgA or free secretory component (FSC) were produced and evaluated.
Response of endangered Poeciliopsis occidentalis sonoriensis in the Río Yaqui drainage, Arizona, to introduced Gambusia affinis

Potential coexistence of the native Yaqui topminnow, Poeciliopsis occidentalis sonoriensis, with introduced mosquitofish, Gambusia affinis, was examined in spring pools and streams in San Bernardino National Wildlife Refuge, southeastern Arizona. Poeciliopsis never exceeded 12% of total poeciliid numbers in a spring pool where Gambusia was present. Body size, fecundity and reproductive effort of Poeciliopsis were significantly higher in this pool than in similar spring pools where Gambusia was absent. Where Poeciliopsis and Gambusia were syntopic in a stream, numbers of Poeciliopsis declined over 1.7 years, until none were collected. Poeciliopsis then increased to > 60% of total poeciliid numbers following flash flooding. Persistence of Poeciliopsis with Gambusia in the spring pool appeared to be a result of compensatory increase in reproductive output, while in the stream it was associated with recurrent flash flooding and a uniform temperature springhead which provided refuge.
A trace minimization problem with applications in joint estimation and control under nonclassical information

Let Λ and Σ be positive-definite matrices of dimensionsn×n andm×n. Then, this paper considers the problem of minimizing Tr[Λ(I+C′C)−1] over allm×n real matrices and under the constraint Tr[ΣCC′]≥1. The solution is obtained rigorously and withouta priori employing the Lagrange multipliers technique. An application of this result to a decentralized team problem which involves joint estimation and control and with signaling strategies is also discussed.
Lovers, Messengers, And Beloved Landscapes: Sandeśakāvya In Comparative Perspective

This article concerns a particular genre of love poetry that has its roots in premodern Hindu India, beginning perhaps as early as the fifth century CE in Sanskrit, flourishing in many different languages from the twelfth to the eighteenth centuries, a period in South Asia marked by the increasing vernacu larization of courtly and sectarian literatures, yet also common right up to the present day.1 This genre?the sandesak?vya or "messenger'* poem?links the powerful emotions of love, separation, and the desire for reunion to beloved landscapes, literary visions of the natural world that echo the separated lovers9 remembered past and anticipated future union. And not only the natural world, of flora and fauna, idealized nature in its fecundities and its dangers, but also landscapes marked by culture, by religion, by the values?political and sectarian ?of the poet who writes the poem. The sandeiaMvya is not only about love, the eternal, ahistorical truths of longing that effect even the gods like R?ma in his desire for his absent wife Sita, the beauties of nature, or the transfigured time of eventual reunion, but it is also about what I call the individual poet's religio-geocultural imaginaire, reflecting regional identity and royal or sectarian patronage. At times sandesa poets will be rigorously sectarian in their approach, emphasizing the superiority of a single temple, zeroing in on its specific god or goddess, and/or a single royal/political center, but more often than not, the chosen beloved landscape, though it is certainly most intimately connected with the powers of a particular god or king, shares its charisma with all gods, goddesses, tributary kings, and peoples who live and work within its blessed
The upper limits of the SNR in radiography and CT with polyenergetic x-rays

The aim of the study is to determine the upper limits of the signal-to-noise ratio (SNR) in radiography and computed tomography (CT) with polyenergetic x-ray sources. In x-ray imaging, monoenergetic x-rays provide a higher SNR compared to polyenergetic x-rays. However, the SNR in polyenergetic x-ray imaging can be increased when a photon-counting detector is used and x-rays are optimally weighted according to their energies. For a particular contrast/background combination and at a fixed x-ray entrance skin exposure, the SNR in energy-weighting x-ray imaging depends on tube voltage and can be maximized by selecting the optimal tube voltage. The SNR in energy-weighted x-ray images acquired at this optimal tube voltage is the highest SNR that can be achieved with polyenergetic x-ray sources. The optimal tube voltages and the highest SNR were calculated and compared to the SNR of monoenergetic x-ray imaging. Monoenergetic, energy-weighting polyenergetic and energy-integrating polyenergetic x-ray imagings were simulated at a fixed entrance skin exposure of 20 mR. The tube voltages varied in the range of 30-140 kVp with 10 kV steps. Contrast elements of CaCO(3), iodine, adipose and tumor with thicknesses of 280 mg cm(-2), 15 mg cm(-2), 1 g cm(-2) and 1 g cm(-2), respectively, inserted in a soft tissue background with 10 cm and 20 cm thicknesses, were used. The energy weighting also improves the contrast-to-noise ratio (CNR) in CT when monoenergetic CT projections are optimally weighted prior to CT reconstruction (projection-based weighting). Alternatively, monoenergetic CT images are reconstructed, optimally weighted and composed to yield a final CT image (image-based weighting). Both projection-based and image-based weighting methods improve the CNR in CT. An analytical approach was used to determine which of these two weighting methods provides the upper limit of the CNR in CT. The energy-weighting method was generalized and expanded as a weighting method applicable in areas other than x-ray and CT. An optimal x-ray tube voltage providing the highest SNR in energy-weighting x-ray imaging was determined for each contrast/background combination. Depending on the imaging task, the highest SNR with energy-weighted polyenergetic x-rays was close to the SNR provided by monoenergetic x-rays. In CT, projection-based weighting provided higher CNR than image-based weighting, thus determining an upper limit of the CNR in CT. The weighting approach can be applied to imaging methods with contrast mechanisms other than x-ray interaction. A unique, task-dependent tube voltage exists in photon-counting x-ray and CT that provides the highest SNR with polyenergetic x-rays. The highest SNR achieved in photon-counting energy-weighted x-ray and CT can approach the SNR of monoenergetic x-ray and CT imaging, depending on the imaging task.
Functional ANOVA Models for Generalized Regression

The Functional ANOVA model is considered in the context of generalized regression, which includes logistic regression, probit regression, and Poisson regression as special cases. The multivariate predictor function is modeled as a specified sum of a constant term, main effects, and selected interaction terms. Maximum likelihood estimate is used, where the maximization is taken over a suitably chosen approximating space. The approximating space is constructed from virtually arbitrary linear spaces of functions and their tensor products and is compatible with the assumed ANOVA structure on the predictor function. Under mild conditions, the maximum likelihood estimate is consistent and the components of the estimate in an appropriately defined ANOVA decomposition are consistent in estimating the corresponding components of the predictor function. When the predictor function does not satisfy the assumed ANOVA form, the estimate converges to its best approximation of that form relative to the expected log-likelihood. A rate of convergence result is obtained, which reinforces the intuition that low-order ANOVA modeling can achieve dimension reduction and thus overcome the curse of dimensionality.
Interpretation of laser-generated low-order Lamb waves for elastic modulus measurements in thin films

Abstract Variability in Lamb waveform structure with film thickness, material, source laser spot size and source laser power density was observed during ultrasonic measurements for determination of elastic moduli of metallic films from 1 to 25 μm thick. To determine the effect of waveform variability on ultrasonic velocity measurements (and, in turn, on elastic modulus calculations), a series of experiments were performed in which Lamb waves were excited in free standing films using a pulsed Nd:YAG laser and detected using heterodyne interferometry. It was shown that, regardless of waveform shape, the velocity of the first arrival was that of the lowest order symmetric Lamb wave for a frequency-thickness product approaching zero.
In situ X-ray diffraction study of melting in gold contacts to gallium arsenide

Abstract By in situ X-ray diffraction, we have obtained direct evidence for the distinction in melting temperature between the first and subsequent heating in ∼ 1000 A gold contacts to GaAs. During the first heating, melting occurred at 456–500°C and is attributed to the melting of a reaction product tentively identified as the orthorhombic AuGa compound (50 at.% Ga), which formed in the solid state. The minimum temperature required for the solid-state reaction and the melting temperature decreased with decreasing hydrostatic pressure. During second and subsequent heating, melting occurred at 410–415°C and is attributed to the melting of β AuGa (or Au7Ga2), which formed after the first melting-solidification cycle. At high cooling rates (e.g. 40°C/min) during the first solidification, β was observed together with a phase (tentative Au2Ga) which increased in proportion with increasing cooling rate.
Aquaporins at a glance.

With a concentration of 55,000 mM, water is by far the most prevalent molecule in biological systems. For many years it was assumed that biological membranes are freely water permeable, so that the existence of a family of water channels would not have been predicted. However, biophysical studies in
A demonstration of a cooperative communication scheme using software defined radio

Cooperative communication is a promising approach to improve the reliability of a received signal at the physical layer. Cooperating nodes create a virtual MIMO system that provides spatial diversity even though the nodes have a single antenna. Therefore, tremendous improvements in system capacity and delay can be achieved. An implementation approach has been pursued in this demonstration to confirm the viability and efficacy of cooperation at the physical layer. The implemented cooperative physical layer scheme is called CoopPHY and is based on Cooperative Coding. In this technique, the source node transmits only a portion of its encoded data bits based on channel conditions among cooperating nodes. Helper nodes transmit the rest of the encoded bits. The destination node, finally, combines and decodes signals received via different channels and therefore increases the decoding reliability.In this demo, a Matlab video clip is streamed frame by frame from a source to destination node using sequentially the direct communication scheme, relaying via one helper, relaying via another helper and finally cooperative scheme. CoopPHY protocol delivers a smooth user experience, while the video playout over the direct scheme shows frequent distortions. In addition to this cooperative coomunication shows better quality than just relaying via any of the helpers. Lab's website: http://witestlab.poly.edu/
Evidence for an androgen binding component in human placental cytosol.

A high-affinity, low-capacity androgen binding component is present in human term placental cytosol. A synthetic androgen tracer, [3H]-R1881, was bound by a single class of binding sites with a Kd of 2.73 ± 1.25 × 10−9 M and a concentration of binding sites of 157 ± 73 fmol/mg protein (N = 20). In competitive binding studies, R1881, T, 5αT, androstenedione and DHEA, were active competitors, but not estradiol, progesterone or Cortisol. The [3H]-R1881 macromolecule complex exhibited a sedimentation coefficient of 4–5 S under low and high salt conditions, and the radioactive tracer was displaced by a 100-fold excess of unlabelled R1881. This binding component has characteristics of high-affinity, low-capacity, sedimentation behaviour and specificity, commonly attributed to androgen “receptors”.
CHEMISTRY: WHAT DOES ONE NEED TO KNOW?

. The general knowledge and understanding that every teacher of religion and science should have relative to chemistry can be found in the answers to three major questions. In my own response to the first question, How did chemistry emerge as a discipline? I trace the origins, establishment, and subsequent historical significance of cosmology. I contend that chemistry is “the obvious, oldest science” and, as such, has played a key role among the sciences in agelong human efforts to understand reality. In my response to the second question, How do chemists currently view (cosmic) reality? I outline three prominent examples in support of my contention that chemistry, despite being “the obvious, oldest science,” is seen by some as playing only a tacit role in current efforts to (re)integrate religion and science. In my response to the third question, How do chemists currently view ultimate reality and meaning? I argue that “unifiers” in chemistry can also now play a key role in a reality revolution that is pointing humankind not only toward a possible historical (re) integration of religion and science but also toward a return to cosmology.
Positioning Tolerances of Beam Line Magnets

The positioning tolerances of magnets are an important consideration in the design and installation of a beam line. A misaligned magnet can both shift the beam centroid and affect the beam line transmission characteristics. To first order and without misalignments, the coordinates at any point of a beam particle are given as a transfer matrix times the initial coordinates. To this we add a term linear in the misalignment parameters giving the beam centroid shift, and a term bilinear in the initial particle coordinates and the misalignment parameters giving the effect on the beam focal properties. This formalism has been incorporated into the computer program TRANSPORT. The effect of either a known misalignment or an uncertainty in position may be exhibited. In a single run, up to ten magnets may be separately misaligned, and their separate effects on the beam coordinates printed in a table.
Charging-assisted hydrogen release mechanism in layered boron hydride

We present a first-principles study of the dehydrogenation mechanism of a recently proposed layered boron hydride (B${}_{2}$H${}_{2}$) for hydrogen storage. The nudged elastic band method is employed to study the kinetic energy barrier against the release of hydrogen. Introducing additional charges into the B${}_{2}$H${}_{2}$ system reduces the electron deficiency of boron layer thereby lowering the dehydrogenation kinetic energy barrier. Finite-temperature molecular dynamics simulation further confirms the release of hydrogen atoms and the formation of molecular hydrogen upon charging the system. The boron network remains intact throughout the simulation up to at least 500 K. These results suggest a charging-assisted dehydrogenation mechanism in this system.
Travel behavior of immigrants: An analysis of the 2001 National Household Transportation Survey

The purpose of this paper is to examine the relationships between travel behavior and immigrant status. The National Household Travel Survey (NHTS) allows us to explore the relationships between travel behavior and characteristics that are usually hard to discern in surveys with smaller samples. The correlation between travel behavior and immigrant characteristics such as place of birth and year of immigration in the US was tested while controlling for spatial and socio-demographic variables. The effects of place of birth and year of arriving to the US were found to be significant for some places of birth and for immigrants who entered the US in recent years. Understanding the differences in travel behavior and the possible explanations for these differences can help in modeling travel demand, finding policies best suited to meeting the travel needs of foreign-born communities, and addressing environmental justice concerns.
Use of a Fish Health Condition Profile in Assessing the Health and Condition of Juvenile Chinook Salmon

Abstract The fish health condition profile, a simplified system for assessing fish health and condition, was originally developed for fish hatcheries and feral trout populations in Utah. We evaluated the method during routine health assessments of juvenile fall chinook salmon (Oncorhynchus tshawytscha) reared in net pens in the Columbia River in 1986 and 1987. The procedure yielded a thorough assessment of the condition offish held under various rearing conditions. This assessment was generally consistent with results of regular diagnostic examinations completed by certified fish health pathologists. The simplicity and availability of the system to most field biologists make it useful for monitoring fish in culture facilities as well as fish from wild stocks. This system may provide the framework for developing a more comprehensive smolt condition index that could be used to evaluate the general condition of juvenile anadromous salmonids before release or during out-migration.
Suppression of Endothelin-1 Production by Heparin Disaccharides. † 1652

Endothelin-1 (ET-1), the most potent vasoconstrictor peptide in nature, is involved in systemic and pulmonary hypertension and in closure of the ductus arteriosus in neonates. Heparin, a heterogeneous glycosaminoglycan, suppresses the production of ET-1 in human unbilical vein cultured endothelial cells(HUVEC). We have shown that the most negatively charged fractions of heparin have the highest ET-1-suppressive activity. This effect of heparin is independent of size, down to 2,400 daltons (octasaccharide).
Evidence for short-circuiting of the detritus cycle of seagrass beds by the green turtle, Chelonia mydas L.

Abstract Evidence is presented for the potential role of Chelonia mydas L. in reducing the decomposition time of Thalassia testudinum Banks ex Konig leaves. During the annual cycle of seagrasses, the plants produce organic matter, undergo senescence, and the leaves die and are exfoliated to decompose in situ or to be exported out of the system. It may require up to 8 wk for 60% of the initial weight of leaves to be lost during decomposition, and even a longer time may be required for this detrital material to be of a size and nutritional state beneficial to fishery organisms. Food material from the gastro-intestinal tracts of two green turtles (50–82 kg), collected off Nicaragua, was analyzed for total organic nitrogen, amino-containing compounds, and organic carbon. Based on these analyses and on information on fecal production, we estimated that the green turtles we studied would individually consume ≈ 280 g dry wt of Thalassia leaves daily. An average of only 34% of the ingested nitrogen was removed between the esophagus and rectum, and over the same length there was a two-fold increase in amino-acid content per g of material. The pre-fecal material was highly fragmented and had a nutritional quality, measured as C: N, superior to the food source. About 2.9 g N are produced daily as fecal matter, in contrast to an estimated nitrogen release of ≈ 0.04 g daily from decomposition of the same amount of leaf material. Thus, the green turtle, although absorbing nutrients, serves to short-circuit the time course for normal decomposition and enrichment of seagrass leaves.
Boundaries and interfaces in ultrafine grain composites

Abstract The present study was motivated by two questions. First, what are the characteristics of grain and phase boundaries in a nanostructured material containing multiple phases? Second, what is the influence of these interfaces on mechanical behavior? Accordingly, a three-constituent Al 5083/B 4 C ultrafine grain (UFG) composite, consisting of a coarse grain (CG) phase (1–2 μm), an UFG phase (100–200 nm) and B 4 C particles (∼0.7 μm), was selected for study. Interest in this particular Al 5083/B 4 C system stems from its hierarchical architecture, which comprises multiple scales, as well as from a reported yield strength of 1145 MPa. The associated grain boundaries (GB) and interfaces were investigated by transmission electron microscopy (TEM), high-resolution TEM, energy dispersive X-ray spectroscopy and electron energy loss spectroscopy methods. The role of high/low-angle GB, equilibrium and non-equilibrium GB within and between the CG and UFG regions, twin boundaries, twist transition boundaries and impurity segregation at GB in strengthening mechanisms is discussed.
Virtual clock: a new traffic control algorithm for packet switching networks

A challenging research issue in high speed networking is how to control the transmission rate of statistical data flows. This paper describes a new algorithm, VirtualClock, for data traffic control in high-speed networks. VirtualClock maintains the statistical multiplexing flexibility of pocket switching while ensuring each data flow its reserved average throughput rate at the same time. The algorithm has been tested through simulation.
Operating experience of an ECR ion source on a high voltage platform

The ATLAS PII-ECR ion source is the first ECR ion source to be designed for operation on a high voltage platform. The source system is required to provide beams of heavy ions with a velocity of 0.01c for subsequent acceleration by the superconducting ATLAS Positive Ion Injector linac. The ability of the system to provide high charge state ions with velocities up to 0.01c is possibly unique in the world today and as such has generated significant interest in the atomic physics community. A beamline for atomic physics has been installed and is now in use. The source began operation in October, 1987. The source capabilities and operating experience to date will be discussed. Other ECR-accelerator combinations will be compared to the ATLAS system.
Bayesian Estimation of the Axial Position in Astigmatism-Based Three-Dimensional Particle Tracking

Accurate estimation of the axial position of a molecule using a single lateral image remains a challenge in fluorescent single particle tracking. Here, a principled algorithm for the Bayesian estimation of the axial position of a molecule in three-dimensional astigmatism-based particle tracking is proposed. This technique uses the data from a calibration image set to derive the position without assuming a functional form for the abberated defocusing curve. Using a calibration image set from forty 57 nm beads, the axial position is calculated, and the error associated with position estimation is discussed. This method is compared to previously published algorithms.
Recognition and Significance of Inherited Quartz Overgrowths in Quartz Arenites

ABSTRACT Inherited quartz overgrowths represent remnants of cement adhering to a grain's surface from a previous sedimentary cycle and can be recognized in petrographic studies on the basis of textural criteria. They may occur as rounded, double, or penetrating overgrowths. Since these features occupy only a part of a grain's surface and are randomly positioned, when studied in two-dimensional sections the likelihood of their being transected and observed is significantly less than their whole-rock abundance. This has resulted in an underestimation of their importance as a provenance indicator. Probability that a random cut will transect a cap of inherited cement on any particular grain depends upon proportion of the grain's surface covered by the cap, position of the cap on the grain's surfac , and orientation of the cut through the grain. An experiment was devised to analyze the relationship between size of a grain-coating cap and likelihood that it will be transected in a random cut. This involved using an eccentric stereonet, one in which the origin is not at the projection sphere's center, to project random planes. Results of the experiment were plotted as a curve and then derived mathematically. Since size of a coating cap is related to its projection angle measured from the sphere's center, a second experiment was devised to determine the relationship between projection angles and equivalent apparent projection angles seen when a cut does not pass through a sphere's center. It was found that the true projection angle equals the mode of apparent projection angles. Relati nships determined in these two experiments enable calculation of the whole-rock proportion of grains with inherited overgrowths from petrographic data. Although at the present time results must be considered as estimates, this capability leads to a more precise understanding of importance of inherited overgrowths as an indicator of sedimentary provenance. The procedure was applied to samples of Upper Precambrian quartz arenites from the Uinta Mountain Group, the Grand Canyon Supergroup, and the Belt Supergroup, resulting in calculated whole-rock proportions of grains with inherited overgrowths that are, in general, twice the values observed in thin section. This procedure may also be useful in a variety of other applications, including studies of sediment distribution, intrabasinal sedim nt maturation, lithostratigraphic correlation, and rates of grain surface abrasion.
Optical transitions in the isoelectronically doped semiconductor GaP:N: An evolution from isolated centers, pairs, and clusters to an impurity band

In heavily nitrogen doped GaP, we show how isoelectronic doping results in an impurity band, and how this is manifested as a large band-gap reduction and an enhanced band-edge absorption. Heavily doped GaP:N or GaP{sub 1-x}N{sub x} exhibits properties characteristic of both direct and indirect gap semiconductors. Exciton bound states associated with perturbed nitrogen pair centers and larger GaN clusters are observed. This paper indicates that to properly describe the properties of an impurity band, a hierarchy of impurity complexes needs to be considered. Our data also suggest that the excitonic effect plays a role in the impurity band formation and band-gap reduction. (c) 2000 The American Physical Society.