cssi/SciSciGPT-SciSciNet huggingface dataset:
Geometric phase in Bohmian mechanics

Abstract Using the quantum kinematic approach of Mukunda and Simon, we propose a geometric phase in Bohmian mechanics. A reparametrization and gauge invariant geometric phase is derived along an arbitrary path in configuration space. The single valuedness of the wave function implies that the geometric phase along a path must be equal to an integer multiple of 2π. The nonzero geometric phase indicates that we go through the branch cut of the action function from one Riemann sheet to another when we locally travel along the path. For stationary states, quantum vortices exhibiting the quantized circulation integral can be regarded as a manifestation of the geometric phase. The bound-state Aharonov–Bohm effect demonstrates that the geometric phase along a closed path contains not only the circulation integral term but also an additional term associated with the magnetic flux. In addition, it is shown that the geometric phase proposed previously from the ensemble theory is not gauge invariant.
DELTA-1 IS A REGULATOR OF NEUROGENESIS IN THE VERTEBRATE RETINA

Abstract In the retina, cell fate determination is thought to be regulated by a series of local cell–cell interactions. Evidence suggests that retinal precursors utilize Notch-mediated intercellular signaling to regulate their fates. However, the identity of the endogenous ligand and its role in the Notch-signaling pathway is not well understood. We have identified C-Delta-1 as the putative endogenous ligand for Notch, in the developing chick retina.C-Delta-1is coexpressed spatially and temporally withC-Notch-1and their expression is associated with the temporal aspects of cell birth in the developing retina. This suggests that Delta–Notch signaling is utilized to maintain progenitors in an uncommitted state and that a subtle fluctuation in this signaling helps to sort out competent cells during successive cell-fate determination. We have tested the latter possibility in the specification of the ganglion cells. In early stages of retinal development when ganglion cells are the predominant cells born, decreasingC-Delta-1expression with antisense oligonucleotides increases the proportion of RA4 antigen-expressing ganglion cells which are recruited predominantly in the periphery. Conversely, use of exogenousDrosophilaDelta leads to a decrease in the RA4 antigen-expressing ganglion cells. Our results suggest that C-Delta-1 activation of the Notch pathway regulates the specification of retinal neurons in general and of ganglion cells in particular.
A multilevel and multigrid optical tomography based on radiative transfer equation

Based on a multigrid forward solver of radiative transfer equation for optical imaging, an efficient multilevel simultaneous reconstruction of absorption and scattering coefficient is presented, in which L 1 minimization can be used to localize the unknowns, especially in the presence of sparse unknowns.
State Power, Linkage Mechanisms, and Diversion against Nonrivals

Mitchell and Prins (2004) have recently found that diversion from high levels of inflation is observed only among enduring rivals. However, neither this nor any other cross-national test of the rel...
“Stable” Defects as, Metastable Defects in a-Si:H

An expanded kinetic description of formation and anneal of metastable defects (MSDs) in a-Si:H shows that (1)the apparently “stable” defects are just a statistical subset of the total density of potential MSD sites; (2)the temperature dependence of the saturation density of MSDs has three distinct regions that have not been recognized; (3)the effects of doping in increasing both the density of “stable” defects and the sensitivity to light are readily explained by an increase in the density of total potential defect sites, not just defects; (4)the defects in good undoped material are chemical in origin, not intrinsic to the disordered state of the material.
THE APPENDIX AS RIGHT URETERAL SUBSTITUTE IN CHILDREN

Purpose: The appendix has occasionally been used to replace sections of the right ureter. We reviewed the literature of the last 25 years on the use of the appendix as right ureteral replacement and report our experience with right ureteral substitution using the appendix.Materials and Methods: We retrospectively reviewed the charts of 3 children who underwent appendiceal replacement of the right ureter. The appendix replaced the upper third of the ureter and the lower ureter in 1 and 2 cases, respectively.Results: Followups of 4, 7 and 15 years, respectively, demonstrated that the appendix transports urine satisfactorily and permits renal function to be maintained with no evidence of obstruction.Conclusions: We believe that our small series supports the use of the appendix as a right ureteral substitute in select cases.
CIE Interlaboratory Comparison of Measurements of Photocell Spectral Sensitivity

The results of an interlaboratory comparison of measurements of relative spectral sensitivity of vacuum photocells are summarized. The comparison was part of the work of the CIE Photometry and Radiometry Committee (TC-1.2). Nine laboratories measured two cells each. The results were corrected for the drifting of relative spectral sensitivity of each cell. The standard deviation of an individual measurement on a cell without filter was less than 2% from 450 nm to 620 nm, increasing to 5% at 390 nm and 690 nm. The standard deviation was larger for a V(λ) corrected cell, being less than 2% in the range 490–600 nm and increasing to 5% at 475 nm and 660 nm. The largest errors were probably caused by wavelength and bandwidth errors.
Toward a more quantitative measure to assess severity of dysphonia posttherapy: preliminary observations.

Summary Objectives/Hypothesis The present research compares the efficacy of using the Dysphonic Severity Percentage (DSP) scale to the equal-appearing interval scale posttherapy . The initial pretherapy investigation was conducted to determine a more quantitative measure to rate the severity of dysphonia perceptually, because rating scales have shown considerable interrater variability. The posttherapy study is a follow-up to the initial research. Methods The initial research involved counting the nondysphonic syllables in 10 participants with moderate-to-severe dysphonia (phonotrauma) to obtain a DSP during spontaneous speech and paragraph reading. The present posttherapy research used the same participants, the same raters, and the same method of assessment during spontaneous speech. The voice samples were both recorded and transcribed for simultaneous analysis and randomly presented to five raters, four of whom were experienced with voice disorders; one rater was a trained student. In this study, the dysphonic syllables were counted to obtain a DSP. Results As in the pretherapy investigation, the DSP in the posttherapy study was found to have high interrater reliability and to be a more quantitative perceptual assessment of voice than the interval scale. Additionally, the reliability of the difference scores between pre- and posttherapy results on the Cronbach's alpha was high on the DSP scale (0.901), but dropped to 0.506 on the interval scale. Moreover, the DSP rating scale yielded greater specificity in terms of vocal improvement posttherapy than the interval scale. The interval scale tended to mask the variation in vocal improvement among participants because of the limited choices presented.
Quantitative relationships between structure and pharmacokinetic parameters using molecular connectivity chi indices I: Substituted 2-sulfapyridines.

Quantitative relationships between the structure and pharmacokinetic parameters of several compounds have been derived using the molecular connectivity approach. The correlation coefficients of equations obtained using the Chi indices (χ) as predictor parameters were compared favorably with those obtained by the linear free energy approach, where physicochemical parameters have been used as predictor variables. High correlation coefficients (r) for the first-order elimination rate constant (r = 0.86), total body clearance (r = 0.89), and protein binding association constant (r = 0.78) for substituted 2-sulfapyridines were obtained. However, including the pKa (indicative of electronic effects) of the compounds within the equation as a predictor variable caused an increase in the correlation coefficients.
Point-of-Purchase Calorie Labeling Has Little Influence on Calories Ordered Regardless of Body Mass Index

The obesity epidemic has incited legislation aimed to inform consumers of the nutritional value of food items available in restaurants and fast food establishments, with the presumption that knowing the caloric content in a meal might enable patrons to make healthier choices when ordering. However, available research shows mixed results regarding consumers' use of calorie information to promote healthier purchases. The aim of this study was to determine whether menu type, specifically having viewed a menu with calorie disclosures or not, would have an impact on how many calories were in a lunch meal ordered by a patron. Additionally, we sought to identify body mass index (BMI) as a moderator of the relationship between viewing a menu with or without calorie information and the number of calories an individual orders for lunch. Two hundred forty-five adults participated in the study and completed the questionnaire. Results indicated neither menu type, nor reporting having seen calorie information, was significantly related to the number of calories in the foods that participants ordered, even after controlling demographic variables age, sex, income, education, race/ethnicity, and BMI. BMI did not serve as a moderator in the relationship between menu type and food calories ordered. Implications for policy change and clinical work with overweight and obese patients are discussed.
GABAA receptor-mediated mechanisms contribute to frequency-dependent depression of IPSPs in the hippocampus.

Intracellular recordings from in vitro guinea-pig hippocampal slices were obtained to investigate the mechanisms underlying activity-dependent depression of inhibitory postsynaptic potentials (IPSPs) in Ca1 pyramidal neurons. IPSPs were studied following blockade of glutamatergic transmission. Attenuation of both fast and slow IPSP components was apparent at stimulus rates of >0.2 Hz, but the late IPSP showed depression at even lower rates of stimulation. Overlap of these events made resolving response components during depression difficult. Fast IPSPs were isolated using CsCl-filled microelectrodes, blocking slow potassium-dependent IPSPs and reversing the chloride gradient. Under this condition repetitive stimulation did not induce IPSP depression. Other experiments showed slow IPSP depression at stimulus rates of <0.5 Hz was relieved in the presence of picrotoxin which antagonizes GABAA events. These results suggest that activity-dependent depression of the fast IPSP results largely from chloride accumulation as a consequence of repetitive activation. Depression of the slow IPSP appears to arise from at least two components: (1) a masking of the slow hyperpolarization resulting from an apparent increase in the depolarizing GABA response due to chloride accumulation; and (2) a novel process involving GABAA receptors, perhaps mediated through presynaptic inhibition.
Human factors/usability barriers to home medical devices among individuals with disabling conditions: in-depth interviews with positive airway pressure device users.

Abstract Background Evidence suggests that medical equipment often fails to accommodate the needs of individuals with disabling conditions. Few studies have focused on the accessibility of home medical devices such as positive airway pressure (PAP), which is a type of home medical equipment prescribed for long-term therapy. Objective The purpose of this study was to explore in detail the types of difficulties experienced by patients with physical/sensory impairments who use PAP devices, as an initial step in designing a questionnaire to survey users about this topic. Methods In this descriptive study, in-depth interviews were conducted with 19 participants (9 patients with physical/sensory impairment and 10 health care providers). Interviews were coded and analyzed for major topics. Results Participants detailed the numerous ways in which current PAP devices fail to meet the needs of individuals with physical/sensory impairments (e.g., tremor, poor depth perception, paresis), by requiring patients to perform manually difficult tasks, such as inserting PAP parts through small apertures, attaching parts using a twisting motion, and lifting arms overhead to apply PAP headgear. These demands contributed to patients' frustration with and reduced usage of the home medical device. Conclusions Our findings suggest that home medical devices such as PAP may not be currently designed to meet the needs of some users with physical/sensory impairments. Additional studies are needed to measure the prevalence and impact of impairment-related barriers on PAP adherence for this common medical equipment.
Mu Opioid Signaling Protects Against Acute Murine Intestinal Injury in a Manner Involving Stat3 Signaling

Opiates have long been used as analgesics to relieve pain associated with various medical conditions. Here, we evaluated the effect and mechanism of mu opioid signaling on the intestinal wound healing response and assessed downstream pathways known to be protective against intestinal injury. Mice (C57BL/6) were exposed to 3% dextran sodium sulfate (DSS) for 7 days or 4% DSS for 5 days followed by 7 days of water. The mu opioid receptor (MOR)-specific agonist [D-Arg2,Lys4]dermorphin-(1,4)-amide (DALDA) and the antagonist cyprodime were injected s.c. daily for in vivo studies or used for in vitro analysis. We found that MOR activation attenuated DSS-induced histologic and gross intestinal injury and weight loss; diminished Ifng, Tnf, and Il6 mRNA expression; and promoted intestinal healing during recovery. DALDA also enhanced colonocyte proliferation (Ki-67 staining) by 350%. MOR activation increased Stat3 phosphorylation in both DALDA-treated mice and the CMT-93 cell line. Importantly, DALDA-induced colonocyte migration was completely ablated by shStat3 knockdown. Together, this work shows that MOR activation protects against and enhances recovery from DSS-induced intestinal injury. This is associated with an increase in Stat3 activation. Furthermore, Stat3 is required for DALDA-induced colonocyte migration. Consequently, manipulation of MOR signaling may represent a novel means to promote mucosal healing and to maintain intestinal homeostasis after intestinal injury.
In vitro studies on the metabolic activation of the furanopyridine L-754,394, a highly potent and selective mechanism-based inhibitor of cytochrome P450 3A4.

L-754,394, a furanopyridine derivative, is an experimental anti-HIV agent which has been shown to be an unusually potent and selective inhibitor of cytochrome P450 3A enzymes in a number of mammalian species. In the present studies, L-754,394 was demonstrated to undergo NADPH-dependent metabolic activation in hepatic microsomal preparations from rats, dogs, rhesus monkeys, and humans to electrophilic intermediates which became bound covalently to cellular proteins. The extent of binding was species-dependent, the highest levels being observed with liver microsomes from rhesus monkeys. Inclusion in incubation media of the nucleophilic trapping agents glutathione, cysteine, or methoxyamine led to a modest (15−25%) decrease in the covalent binding, while trichloropropylene oxide, an inhibitor of epoxide hydrolase, had no effect. When L-754,394 was incubated with monkey liver microsomes, the corresponding dihydrofurandiol was identified as a metabolite by liquid chromatography−tandem mass spectrometry. In con...
High cycle fatigue mechanisms in a cast AM60B magnesium alloy

We examine micromechanisms of fatigue crack initiation and growth in a cast AM60B magnesium alloy by relating dendrite cell size and porosity under different strain amplitudes in high cycle fatigue conditions. Fatigue cracks formed at casting pores within the specimen and near the surface, depending on the relative pore sizes. When the pore that initiated the fatigue crack decreased from approximately 110 μm to 80 μm, the fatigue life increased two times. After initiation, the fatigue cracks grew through two distinct stages before final overload specimen failure. At low maximum crack tip driving forces (K max 2.3 MPam), the fatigue crack propagated primarily through the β-Al 12 Mg 17 particle laden interdendritic regions. Based on these observations, any proposed mechanism-based fatigue model for cast Mg alloys must incorporate the change in growth mechanisms for different applied maximum stress intensity factors, in addition to the effect of pore size on the propensity to form a fatigue crack.
The influence of clouds on climate with A focus on high latitude interactions

The global cloud distribution is recognized as forming a major component of the Earth's climate through its influence on both the energy and moisture exchanges in the earth-atmosphere system. This review concentrates on the radiative effects of clouds and examines a number of modelling and empirical studies that have addressed the possible significance of the role of cloud cover in climate change. This question is still not fully resolved. One reason for this is inadequate data and, therefore, some of the cloud climatologies available and the associated problems of data collection and interpretation are discussed. The review focuses specifically on interactions at high latitudes and describes recent studies which suggest that there may be a relationship between sea ice extent and cloud cover. Some possible consequences of this are discussed in the context of a high latitude response to climate change.
A multivariate generalization of von neumann's ratio

A multivariate generalization, Rv, of von Neumann's ratio is proposed. The null distribution is evaluated under the assumption that observations are independent, identically distributed with a multivariate normal distribution. The Rv statistic provides an intuitively appealing measure of multivariate association which indicates whether the observed serial correlation is positive (the distance between successive observations is less than expected) or negative. The operating characteristics of the corresponding one-sided test is evaluated. A two-sided likelihood ratio test (LR) proposed previously is modified to obtain a one-sided test. Comparisons of these two procedures indicates that both provide accurate control over the size of the test, but that the Rv test appears to be more powerful.
Effect of laser-induced excitation of oxygen on ignition in HCCI engines analysed by numerical simulations

Lack of proven means to control ignition impedes practical implementation of homogenous charge compression ignition (HCCI) engines. In the present paper, we investigate if laser-induced excitation of oxygen might aid solution of the ignition control problem in HCCI engines. Simulations by previous researchers showed laser-induced excitation of oxygen enhances ignition in supersonic combustion. Based on this previous research, we extend a chemical kinetic mechanism for propane autoignition to include reactions for two excited oxygen states, O2(a1Δ g ) and O2(b1Σ g +). Simulations examined the effect of each of these excited O2 states upon ignition timing in an HCCI engine. Results indicate that achieving useful control of the combustion process requires substantial conversion of O2 to either of the excited states. At the required level of excitation, the power required for the laser may lower engine efficiency.
Adenotonsillectomy in the very young patient: cost analysis of two methods of postoperative care.

Abstract Postoperative management of the patient younger than 36 months undergoing adenotonsillectomy has been the subject of many debates. Concerns for early postoperative complications such as airway obstruction, emesis, dehydration, and hemorrhage have led many physicians to consider overnight hospitalization following adenotonsillectomy in very young children. Trends in health care management have had increasing focus on cost effective means of treating patients to limit unnecessary expenditure on the part of the patient, physician, and hospital facility. The purpose of this retrospective review was to analyze two methods of early postoperative management in children less than 36 months old undergoing adenotonsillectomy at the Children’s Hospital, San Diego from 1992 to 1997. Three hundred and seven cases were reviewed. Same-day discharge was compared with overnight inpatient observation based on the cost analysis of these two methods of postoperative care. Postoperative care was based on length of stay in the recovery room and as an inpatient. Expense of postoperative care was based on cost calculation for the recovery room and overnight hospitalization. Of the 307 patients, 194 went home the day of surgery and 113 were observed overnight in the hospital. Average hospital cost was higher in the outpatient group than in the inpatient group ( P P
Back-surface gold mirrors for vibrationally resonant sum-frequency (VR-SFG) spectroscopy using 3-mercaptopropyltrimethoxysilane as an adhesion promoter.

Back-surface mirrors are needed as reference materials for vibrationally resonant sum-frequency generation (VR-SFG) probing of liquid–solid interfaces. Conventional noble metal mirrors are not suitable for back-surface applications due to the presence of a metal adhesion layer (chromium or titanium) between the window substrate and the reflective metal surface. Using vapor deposited 3-mercaptopropyltrimethoxysilane (MPTMS) as a bi-functional adhesion promoter, gold mirrors were fabricated on fused silica substrates. These mirrors exhibit excellent gold adhesion as determined by the Scotch® tape test. They also produce minimal spectroscopic interference in the C–H stretching region (2800–3000 cm–1), as characterized by VR-SFG. These mirrors are thus robust and can be used as back-surface mirrors for a variety of applications, including reference mirrors for VR-SFG.
Seasonal distribution and flux of radium isotopes on the southeastern U.S. continental shelf

[1] Enrichments of radium isotopes in coastal waters have served as indicators of submarine groundwater discharge (SGD). Because coastal waters exchange with the open ocean on a timescale of weeks to months, seasonal patterns of radium isotope distributions may be used to indicate changes in SGD through the year. Here I report the seasonal distributions of four naturally occurring radium isotopes measured throughout the water column of the southeastern U.S. continental shelf, commonly known as the South Atlantic Bight (SAB). The study area extended from Onslow Bay, North Carolina, to Crescent Beach, Florida. Activities of the long-lived isotopes were highest off the coast of Georgia. In the summer, high activities extended throughout the study area, but during spring and winter, they decreased markedly off the coast of SC. The primary source of excess 226Ra and 228Ra (that is activities in excess of open ocean values) is shown to be SGD. Because the activities of these isotopes in SGD differ little with season, the lower excess activities off South Carolina imply lower rates of SGD during the spring and winter. The excess inventories and fluxes of 226Ra and 228Ra provide an estimate of the residence time of water on the shelf. These residence times range from 30 to 60 days with a mean of about 40 days.
Mars Global Reference Atmospheric Model for mission planning and analysis

An engineering model atmosphere for Mars has been developed with many of the same features and capabilities of the highly successful Global Reference Atmospheric Model (GRAM) program for Earth's atmosphere, including mean values for density, temperature, pressure, and wind components, and density perturbation magnitudes and random perturbation profiles for density variations along specified trajectories. This paper outlines the observational and modeling basis behind the development of the Mars-GRAM program, provides a general description of the operations of the Mars-GRAM program (available in FORTRAN-77 on IBM-PC compatible 360k diskettes), and presents some example applications for the Mars-GRAM model.
Geophysical Studies in the Angola Diapir Field

Marine geophysical data on the continental slope west of Angola, Africa, indicate a large (50,000 km2) diapir field. Heat-flow values on the crests of the diapiric structures are systematically 2 to 3 times larger than those measured between these structures. A steady-state model of thermal conductivity contrasts, based on a detailed survey over the diapirs, strongly suggests that the cores of the diapirs are salt.
Joint torque measurement of a direct-drive arm

The design and analysis of joint torque sensors for a direct-drive arm is presented. The direct-drive arm is driven by high torque motors without reducers or other transmission. It can serve as a suitable device for implementing torque control schemes. The direct coupling of motors to their loads reduces friction, eliminates backlash and increases mechanical stiffness. All these are desirable features for precision torque control. The drive system, however, still has some errors due to electric and electromagnetic nonlinearities at the motors and amplifiers. The direct measurement of torque is therefore necessary in order to compensate for these errors. First, two different types of torque measurement are described and compared; an indirect method via current measurement and a direct method using strain gages. Next, the strain gage torque sensor is analyzed. A design principle is developed in order to achieve high sensitivity torque measurement without sacrificing the high mechanical stiffness or degrading the dynamic performance of the drive system. Implementation and experiments are described for verifying the design principle and for evaluating the sensors.
Image formation of a high temperature vacuum evaporation source through combined distillation camera exposures and autoradiography with Au198, Cr51 and W185

Abstract A combination of vacuum distillation self-imaging and autoradiography is described for the production of an image of the vacuum evaporation geometry of an evaporating source at the instant of molecular distillation, or during selected periods throughout the distilling sequence. The mode of the macrodistillation phenomena may be ascertained by the method, which is particularly applicable to the study of distillation phenomena of minute masses of charge material. The system provides an image, the density of which quantitatively represents the intensity of the evaporation rate from any point on the distillation source. A shutter system may be used to provide discrete images of the distillation phenomena at limited, selected time periods throughout the evaporation. The method consists first of the use of a simple vacuum distillation camera. The image of the source being formed on a cold target plate at the image plane and made up of the condensed metal distilland, tagged with its radioactive isotope. Single isotopes or combinations of the tagged metals may be used in the crucible and charge. Radioisotopes used here are Au198, Cr51 and W185. The metallic condensed metal in image array may be so tenuous as to be invisible on this target plate. This condensed tagged metal is placed in gross apposition with a proper autoradiographic emulsion and the resultant photographic negative presents the true image of the distillation intensities at the source. This image may not necessarily coincide with the geometric, mechanical limits of the filament plus charge. The autoradiographic image reproduces the apparent source seen by the target. This special benefit of the method, in that it demonstrates the source region from which the distilling atoms emanate, allows study of wetting phenomena, creep of charge, reflection and distilland scattering phenomena. Image photographic density may be a quantitative measure of the source distillation rate, when the photographic process is standardized. The method has potential in binary isotope distillations to determine simultaneous evaporation phenomena of charge and crucible. The method's resolution theoretically extends to the order of 10 μ and has a sensitivity down to 500 μg charge mass distilled. Source images may consist of as little as 10−10g of metal for certain beta emitters.
Isolation of lipoproteins from thyroxine-labeled human serum.

Ultracentrifugal studies of whole serum and crude Fraction IV to which 131I thyroxine had been added have revealed more than 89% of the radioactivity in the D>1.21 (“bottom”) material. Precipitation with antisera against alpha-1, alpha-2 and beta-lipoproteins resulted in no radioactivity in the precipitates. Analysis of a subtraction of Fraction IV-4 rich in TBG revealed no detectable lipid. These findings indicate that thyroxine binding alpha-globulin is not a lipoprotein of the major lipoprotein classes. (Endocrinology 77: 398, 1965)
Multiphase materials with lignin. XV. Blends of cellulose acetate butyrate with lignin esters

Commercially available cellulose acetate butyrate (CAB, unplasticized) was blended in melt and solution with lignin esters having different ester substituents—acetate (LA), butyrate (LB), hexanoate (LH), and laurate (LL). All lignin esters formed phase-separated blends with CAB with domain size depending on processing conditions and the interaction between phases depending on blend components. CAB/LA and CAB/LB revealed the strongest interactions with domain sizes on the 15–30 nm scale as probed by dynamic mechanical thermal analysis and differential scanning calorimetry. The glass transitions (Tg) followed the Fox equation. Broader transitions corresponding to the Tgs of the two parent components were observed for CAB blends with LH and LL. Transmission electron micrographs revealed differences in the phase dimensions of the blends in accordance with chemical and processing (i.e., melt vs solvent) differences. Modest gains in modulus were observed for low contents (<20 wt %) of LA and LB. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 448–457, 1999
Anisotropy of Chemical Bonds in Collagen Molecules Studied by X-ray Absorption Near-Edge Structure (XANES) Spectroscopy

Collagen type I fibrils are the major building blocks of connective tissues. Collagen fibrils are anisotropic supra-molecular structures, and their orientation can be revealed by polarized light microscopy and vibrational microspectroscopy. We hypothesized that the anisotropy of chemical bonds in the collagen molecules, and hence their orientation, might also be detected by X-ray photoemission electron spectromicroscopy (X-PEEM) and X-ray absorption near-edge structure (XANES) spectroscopy, which use linearly polarized synchrotron light. To test this hypothesis, we analyzed sections of rat-tail tendon, composed of parallel arrays of collagen fibrils. The results clearly indicate that XANES-PEEM is sensitive to collagen fibril orientation and, more specifically, to the orientations of carbonyl and amide bonds in collagen molecules. These data suggest that XANES-PEEM is a promising technique for characterizing the chemical composition and structural organization at the nanoscale of collagen-based connective tissues, including tendons, cartilage, and bone.
Fluorescence optical imaging in turbid media using independent component analysis

An information theory approach for optical imaging of fluorescent inhomogeneities within turbid media using independent component analysis is outlined. Results for localization and characterization of fluorescent objects in turbid media from experiments are presented.
Widespread soft-sediment deformation horizons in Lower Silurian strata of the Appalachian basin: distal signature of orogeny

Abstract Sedimentology and stratigraphic mapping of soft-sediment deformed beds (ball and pillow and convolute bedding) in the Lower Silurian of eastern North America demonstrate that these event beds are extremely widespread and that their component sediment layers were not deformed during initial deposition, but slightly later, during shallow burial. Successions of laminated arenaceous beds with interbedded shale in regressive (falling stage) systems tracts of third order depositional sequences appear to have been prone to deformation. Deformed zones are likely the result of shear-induced liquefaction of thixotropic muds and foundering of overlying (carbonate and siliciclastic) silts and sands during very large-scale earthquakes. The distribution of deformed beds, together with increased subsidence, clastic influx, and K-bentonite horizons, provides a meter of intensity and timing of pulses of Silurian orogenesis.
Sustainable rates of sebum secretion in acne patients and matched normal control subjects

Sustainable rates of sebum secretion were measured in twelve subjects with inflammatory acne and in twelve control subjects, matched in age and gender, who had no significant signs of acne. The measurements were made after first depleting the skin of an accumulation of previously secreted sebum by absorption into adherent layers of bentonite clay applied to the center of the forehead for 14 hours. Disks of fine Dacron mesh, embedded in fresh clay, were then applied to the forehead for 3 hours. The disks and adhering clay were then removed and extracted with ether to recover the collected lipids. The sebum recovered during the 3-hour period was measured by quantitative thin layer chromatography. The subjects with acne were found to have an average sustainable sebum secretion rate of 2.51 mg/10 cm2/3 hr, while the control group had an average of 0.81 mg/10 cm2/3 hr. Furthermore, all subjects with acne had secretion rates larger than those of their matched control subjects. The results indicate that a high sebum secretion rate is the decisive factor in inflammatory acne.
Plastic adaptation toward mutations in proteins: Structural comparison of thymidylate synthases

The structure of thymidylate synthase (TS) from Escherichia coli was solved from cubic crystals with a = 133 A grown under reducing conditions at pH 7.0, and refined to R = 22% at 2.1 A resolution. The structure is compared with that from Lactobacillus casei solved to R = 21% at 2.3 A resolution. The structures are compared using a difference distance matrix, which identifies a common core of residues that retains the same relationship to one another in both species. After subtraction of the effects of a 50 amino acid insert present in Lactobacillus casei, differences in position of atoms correlate with temperature factors and with distance from the nearest substituted residue. The dependence of structural difference on thermal factor is parameterized and reflects both errors in coordinates that correlate with thermal factor, and the increased width of the energy well in which atoms of high thermal factor lie. The dependence of structural difference on distance from the nearest substitution also depends on thermal factors and shows an exponential dependence with half maximal effect at 3.0 A from the substitution. This represents the plastic accommodation of the protein which is parameterized in terms of thermal B factor and distance from a mutational change.
Maximum likelihood estimation of variance components in a completely random bib design

ABSTRACT The purposes of this paper are to abstract from a number of articles variance component estimation procedures which can be used for completely random balanced incomplete block designs, to develop an iterated least squares (ITLS) computing algorithm for calculating maximum likelihood estimates, and to compare these procedures by use of simulated experiments. Based on the simulated experiments, the estimated mean square errors of the ITLS estimates are generally less than*those for previously proposed analysis of variance and symmetric sums estimators.
Linear Array Synthesis Via A Constrained Version Of Prony's Method

A technique for designing antenna arrays whose sources are located along a line is presented. Unlike most approaches to linear array synthesis, this technique optimizes source locations as well as source strengths. The technique is based on a modification of Prony's method.
Severe unintentional penetrating abdominal injuries of domestic origin in children

Abstract The authors report five cases in which children sustained severe unintentional penetrating abdominal injuries caused by everyday household items. The five children required emergency surgical intervention. These injuries were potentially preventable. Careful supervision of children and their environment is necessary to prevent this type of injury and to ensure their well-being.
Nucleolar organization in oocytes of gryllid crickets: subfamilies Gryllinae and Nemobiinae.

A cytological and cytochemical survey was made of nucleolar changes during oocyte development in several different species of crickets (Gryllidae) representing the subfamilies Gryllinae and Nemobiinae. A large mass of extrachromosomal DNA is characteristic of the pachytene stage nuclei of all species examined. Nucleolar material accumulates at the periphery of the DNA body as the cells proceed into the diplotene stage of development. As the oocytes proceed through diplotene, the nucleoli reorganize into many small masses which eventually disperse in the nucleoplasm. These changes reflect both an increase in number and in size of the nucleolar material during the diplotene stage and the mode by which dispersal of nucleolar material is accomplished. These differences probably reflect differences in the organization of extrachromosomal nucleolar DNA.
Dose-dependent effects of DDAVP on memory in healthy young adult males: a preliminary study.

Abstract Although several studies have demonstrated the efficacy of the vasopressin analog DDAVP in enhancing human memory, no previous study has reported the dose-response relationship of DDAVP to memory in healthy young adults. The present study was undertaken to explore the dose-response curve for DDAVP on recall of implicational sentences. Five doses of DDAVP (0, 5, 15, 30, and 60 μg) were administered intranasally to healthy young adult male volunteers. Results demonstrated a facilitation in cued recall after treatment with the 60-μg dose and a general impairment in recall after treatment with the 15-μg dose. These effects were independent of subject's weight, vocabulary ability, and concentration of salivary cortisol.
Problem solving as a complex, evolutionary activity: a methodological framework for analyzing problem-solving processes in a computer-supported collaborative environment

Viewed through the lens of complex systems science, one may conceptualize problemsolving interactions among multiple actors, artifacts, tools, and environmental structures as goal-seeking adaptations, and problem-solving itself, as a complex adaptive activity. Theories of biological evolution point to an analogical equivalence between problem solving and evolutionary processes and, thus, introduce innovative methodological tools to the analysis of computer-supported, collaborative, problem-solving processes. In this paper, we present a methodological framework for characterizing and analyzing these processes. We describe four measures that characterize genetic evolution - number, function, fitness, and persistence - to characterize the process of collaborative problem solving, and instantiate them in a study of problem-solving interactions of collaborative groups in an online, synchronous environment. Issues relating to reliability, validity, usefulness, and limitations of the proposed methodology are discussed.
High-resolution UV wavelength reticle inspection

A new reticle inspection system with laser UV imaging has been developed to detect defects on advanced reticles for DUV steppers. The extension to UV wavelength improves the resolution of the imaging optics while maintaining compatibility with current inspection algorithms, thus improving sensitivity and minimum linewidth capability. A system level description of the changes made to the optics, mechanics, and software are presented. Using both programmed defect test masks and real production reticles, initial observations of the nature and frequency of defects detected with this 150 nm sensitivity instrument will be presented. Preliminary characteristics of this system include the number and types of defects captured at multiple pixel sizes. Comparisons with non-UV systems illustrate the advantage of utilizing shorter wavelengths for reticle inspection. The quality of defect review images has a direct impact on the effectiveness and ease-of-use of reticle inspection systems. The high quality, UV images available from the new system can be viewed in both normal and sharpened defect review displays. The defect review images show the result of high NA, UV laser imaging and image sharpening applied at defect review.
The primary transcription unit of the mouse β-Major globin gene

Abstract The transcriptional unit boundaries of the mouse β-major globin gene have been investigated in DMSO-induced murine erythroleukemia cells using mainly labeled RNA produced by in vitro transcription in isolated nuclei. Restriction fragments of a genomic β-major globin clone (Tilghman et al. 1977) representing regions of the 5′ and 3′ portions of the mRNA sequence, the large intervening sequence, as well as regions before the cap site and beyond the poly(A) site of the mRNA were recloned for use in DNA excess hybridization experiments. Equimolar amounts of labeled nascent RNA hybridized to the fragment encoding the capped 5′ end of the mRNA and to fragments extending at least 1000 nucleotides beyond the poly(A) addition site. The existence of continuous transcription throughout this region was shown by: samples of labeled RNA each specifically complementary to one of the globin region fragments all bound to a single strand, presumably the coding strand of the separated strands of the β-globin genomic clone; specific T1 oligonucleotides diagnostic of the region immediately following the poly(A) site of the nuclear RNA were identified in hnRNA labeled in isolated nuclei; the shortest labeled nascent RNA chains bound to the fragment containing the cap site and increasingly longer chains bound in the ordered set of fragments as a function of distance from the cap site. These results suggest the necessity for an endonucleolytic cleavage of a primary transcript followed by polyadenylation in the process of creating the 3′ end of this cellular mRNA, as has previously been demonstrated for every virus mRNA so far studied (Nevins and Darnell 1978; Ford and Hsu 1978; Fraser et al. 1979; Nevins et al. 1980). An analysis of the accumulation of the different RNA sequences labeled in vivo demonstrated a confinement of the sequences transcribed past the poly(A) site exclusively to the nucleus and indicated an even higher turnover rate for these than for the intervening sequences. In addition to the equimolar amounts of labeled nascent RNA complementary to DNA fragments from the cap site through and past the poly(A) site, a smaller amount of labeled RNA hybridized reproducibly to DNA fragments upstream from the cap site. Although this RNA was complementary to the coding strand, it did not appear to be part of the majority of the globin primary transcripts based on size analysis and it was present at only 20% or less of the molarity of the RNA from the globin coding regions.
Response Function of the Second Kind in Many-Body Systems

We analyze a new type of response function which portrays the properties of a system perturbed by an external field in terms of the perturbed two-point correlations of density fluctuations rather than in terms of perturbed averages of physical quantities. This “response function of the second kind” satisfies both fluctuation-dissipation-like theorems, relating it to three-point equilibrium functions, and hierarchical relationship linking it to conventional quadratic (rather than linear) response functions. In the equal-time limit, when the two density fluctuations are observed at the same time, the response function of the second kind is intimately connected to the two-particle correlation function of kinetic theory. This linkage opens an avenue for developing novel approximation techniques for correlated many-body systems.
High Frequency Rays of Cosmic Origin II. Mountain Peak and Airplane Observations

The elimination in penetrating ray experiments of temperature and pressure effects is accomplished through new features in the design of Wulf electroscopes, but especially through immediate reduction in situ of all deflections to volts. Variation of penetrating radiation with altitude and with time of day. — When suitable precautions are taken for eliminating the activity of adjacent rocks, both airplane and mountain peak observations agree in showing a definite variation of the penetrating radiation with altitude alone. Within the limits of experimental error all observations are consistent in showing no dependence of the penetrating radiation upon the time of day or upon the position of heavenly bodies. Absorption coefficients of penetrating rays. — Absorption experiments made on Pikes Peak with lead sheets 4.8 cm thick furnish evidence for the existence on mountain peaks of copious new rays of local origin of no greater hardness than that of gamma rays. If these new rays are assumed to be homogeneous their absorption coefficient is about 3.1 per meter of water. These experiments, however, furnish no definite evidence for the existence of very penetrating rays of cosmic origin. Necessary characteristics of cosmic rays if they exist — Such rays cannot produce as much as 2 ions per cc per sec. at sea level if they have an absorption coefficient not less than 0.25 per meter of water. If cosmic rays exist at all they must be less intense than this, or else they must be more penetrating than anyone has as yet suggested.
Generation of triangulated irregular networks based on hydrological similarity

Distributed hydrologic models typically incorporate topographic data through the use of raster-based digital elevation models. The resampling of high-resolution grid data required to effectively use distributed models, however, can result in the distortion of terrain and hydrographic properties. In this study, we present a geographic information system approach for deriving multiple resolution meshes that conserve physiographic features while significantly reducing the number of computational nodes in a distributed hydrologic model. We utilize triangulated irregular networks ~TINs! which serve to integrate information on the surface topography, hydrographic features and land surface characteristics into an adaptive representation of a basin. We discuss three approaches for constructing TIN models for hydrologic applications: ~1! Traditional, ~2! hydrographic and ~3! hydrological similarityTINs. We focus on the generation of triangulated terrain models using the concept of hydrological similarity provided through a topographic or wetness index. This new method embeds an estimate of the steady-state hydrologic response directly into the basin terrain model. Through a series of case studies, we demonstrate the advantages of the multiple resolution approaches over a range of terrain characteristics, basin scales and elevation data products. Finally, we discuss the implications of TIN terrain representation for watershed simulation with the TIN-based Real-Time Integrated Basin Simulator model.
A pagination-based index structure on a native XML database

How to retrieve and query large XML documents efficiently has become a challenge in the database field for several years. A few efforts have been made in the past to address this issue. In this paper, we present a novel approach using pagination technique and index structure in a native XML database system named CanStoreX. The system is able to handle very large XML documents efficiently using only a small amount of memory space. The experimental results have shown that the index structure proposed in this paper could dramatically improve the performance of the XQuery engine on a pagination based native XML storage.