cssi/SciSciGPT-SciSciNet huggingface dataset:
Measurement of photosynthetic gas exchange in controlled environments.

Early controlled-environment research used growth chambers primarily as “photoperiod rooms” to study effects of environment on long-term plant developmental processes (Downs and Hellmers, 1975). More recently, growth dynamics analysis has been used to measure photosynthetic productivity of crop canopies or individual plants in controlled environments over periods of only a few days (Knight and Mitchell, 1983). However, as the emphasis of controlled-environment research shifts toward definition of optimum growth conditions (Hoff et al., 1982), there will be increasing demand to measure instantaneous photosynthetic response within modified controlled environments. Net photosynthesis and respiration are measured most conveniently as CO2 consumption or evolution, respectively, by a given area or mass of plant tissue over a defined period. At ≈ 3 5 0 μmol·mol –1(μl·liter –1, vpm), CO2 is a trace gas compared to the major components of air (N2, O2, H2Ov). As such, CO2 is detectable to 1 μmol·mol –1 by thermal conductivity gas chromatography (TCD-GC) or infrared gas analysis. The infrared gas analyzer (IRGA) is amenable to continuous-flow monitoring of the CO2 level in air and will detect near-real-time changes in gas-exchange rate by plants as environmental conditions vary. Modem electronic detector systems permit a degree of miniaturization of IRGAs that allows their portability into growth chambers as well as to the field. Gas exchange by chamber-grown plants may be measured for individual attached leaves, entire shoots, or leaf canopies of multiple plants. Various plant enclosure techniques are used for each type of measurement. Because a limited number of off-the-shelf assimilation chambers are available on the commercial market, many researchers have developed their own cuvettes for specific applications. Assimilation chambers often are constructed from transparent acrylic (plexiglass) or polycarbonate (mylar) plastic. Because these plastics adsorb water vapor (H2Ov) and, consequently, CO2
Some Negative Aspects of Crop Rotation

The positive effects of crop rotation for potato (Solanum tuberosum) production are usually emphasized. The quoted benefits generally include improved yield and quality, reduced pest pressure, improved soil condition, and improved plant nutrition. The negative aspects of crop rotation are often overlooked. The purpose of this paper is not to discourage crop rotation, but to identify some of the potential negative factors so that the best rotation schemes can be developed. The selection of the “best” cropping systems is difficult because of the complex interacting factors involved. Some of the “detrimental” effects could be decreased yield and quality for one or more of the following reasons: excess or decreased fertility, increased pest pressure, herbicide residues and soil compaction. Another “detrimental” effect could be lowered income.
LXXIV. The electron theory of thermoelectric and thermionic effects

(1912). LXXIV. The electron theory of thermoelectric and thermionic effects. The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science: Vol. 24, No. 143, pp. 737-744.
Intratubular crystallization of calcium oxalate in the presence of membrane vesicles: An in vitro study

Intratubular crystallization of calcium oxalate in the presence of membrane vesicles: An in vitro study. Background Since urine spends only a few minutes in the renal tubules and has a low supersaturation with respect to calcium oxalate (CaOx), nucleation of CaOx crystals in the kidneys is most probably heterogeneous. We have proposed that membranes of cellular degradation products are the main substrate for crystal nucleation. The purpose of our study was to determine the site of membrane-mediated crystal nucleation within the renal tubules and the required lag time, factors that determine whether crystallization results in crystalluria or nephrolithiasis. Methods Nucleation of CaOx was allowed to occur in five different artificial urine solutions with ionic concentrations simulating urine in proximal tubules (PTs), descending (DLH) and ascending (ALH) limbs of the loop of Henle, distal tubules (DTs), and collecting ducts (CDs). A constant composition crystallization system was used. Experiments were run for two hours with or without the renal tubular brush border membrane (BBM) vesicles. Results The addition of BBM significantly reduced the nucleation lag time and increased the rate of crystallization. The average nucleation lag time decreased from 84.6 ± 43.4 minutes to 24.5 ± 19 minutes in PTs, from 143.6 ± 29 to 70.2 ± 53.4 minutes in DLH, from 17.6 ± 8.6 minutes to 0.625 ± 0.65 minutes in DTs and from 9.54 ± 3.03 minutes to 0.625 ± 0.65 minutes in CDs. There was no nucleation in the ALH solution without BBM for two hours. CaOx dihydrate (COD) was common in most solutions. Calcium phosphate (CaP) also nucleated in the DLH and CD solutions. Conclusions In the absence of membrane vesicles, there was no crystallization in any of the solutions within the time urine spends in the renal tubules. As a result, homogeneous nucleation of crystals anywhere within the nephron appears unlikely. However, BBM-supported nucleation is possible in the DTs as well as CDs. A high crystallization rate in CDs would promote rapid crystal growth and aggregation, resulting in crystal retention within the kidneys and development of nephrolithiasis.
Knowledge-based pattern recognition using an associative processor

An image understanding system often consists of the preprocessing, feature extraction, and classification stages. In this paper we have considered a descriptive approach for the classification. As an illustration, we have considered the problem of identification of sailing crafts. The properties like the position of the mast(s), height of the mast, and type of sails are used as features. The classification scheme is described by a hierarchical tree structure. We have created the knowledge base for the classifier by encoding the classification rules, using an associative processor. A number of operations can be performed with the associative processor. They include: an upward closure, downward closure, union, and intersection. In order to use the processor as a classifier, the intersection has been used. The intersection is achieved by performing a downward closure followed by thresholding. We have used a two- layer nonlinear feedback network as the associative processor. We have also developed a menu-driven input/output interface for the classifier.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Cotton logistics as a model for a biomass transportation system

Abstract To reach the US Department of Energy's goal of replacing 30% of current petroleum consumption by biomass and its products by year 2030, various systems capable of harvesting, storing and transporting biomass efficiently, at a low cost, need to be designed. The transportation system of a cotton gin, which shares several key components with a biomass transportation system, was simulated using a discrete event simulation procedure, to determine the operating parameters under various management practices. The cotton module transportation system, when operating under a FIFO management plan, was found to operate at 77% utilization factor, while the actual ginning process operated at 69%. Two greedy algorithm-based management policies were simulated, which increased the gin operational factor to 100%, but doing so required an increase in gin inventory level. A knapsack model, with travel times, was constructed and solved to obtain the lower bound for the transportation system. The significance of these operating parameters and their links to a biomass transportation system are presented. Using the new management strategies, the utilization factor for the transportation system was increased to 99%. To achieve this improvement, the transportation manager must know where all modules are located and have the ability to dispatch a hauler to any location.
On convergent supersurfaces and public spheres online

This essay considers the civic ecology that is afforded via technologies of convergence. I propose that rather than examining the impact of technology, we consider technology as architecture. This permits us to situate civic tendencies and tensions in socio-cultural context. Thus, rather than measuring beneficial against adverse civic uses of online technologies, we concentrate on how newer civic habits, enabled by online networked platforms, shape and are shaped by our civic ecology.
In vitro culture of pig embryos

Abstract Culture of pig embryos obtained prior to the four-cell stage has been difficult to accomplish. The ‘in vitro developmental block’ at the four-cell stage can be overcome by a number of methods to allow complete development of pig embryos from the one-cell stage to the blastocyst stage in vitro. Mouse oviducts in organ culture have been shown to provide a suitable environment for pig embryo development. Co-culture of pig embryos with oviductal cells or supplementation of culture medium with pig oviductal fluid results in improved embryonic development in vitro. Modifications to simple culture media have demonstrated that glutamine can serve as the sole exogenous energy source for development from the zygote to the blastocyst stage in vitro. Glucose was not inhibitory to the development of pig embryos in vitro. Addition of taurine and hypotaurine to the medium further increased the degree of embryo development in vitro. A number of different media have been reported that support pig embryo development in vitro. Although the nature of the ‘in vitro developmental block’ is not known, a number of methods now exist to circumvent this problem in the pig.
Symmetry of Nonnegative Solutions of Elliptic Equations via a Result of Serrin

We consider the Dirichlet problem for semilinear elliptic equations on a smooth bounded domain Ω. We assume that Ω is symmetric about a hyperplane H and convex in the direction orthogonal to H. Employing Serrin's result on an overdetermined problem, we show that any nonzero nonnegative solution is necessarily strictly positive. One can thus apply a well-known result of Gidas, Ni and Nirenberg to conclude that the solution is reflectionally symmetric about H and decreasing away from the hyperplane in the orthogonal direction.
Rayleigh-wave dispersion along the Hawaiian Swell: a test of lithospheric thinning by thermal rejuvenation at a hotspot

SUMMARY In this paper we present a seismological test of the 'thermal rejuvenation' model for the formation of the Hawaiian Swell, the archetype of a midplate hotspot swell. Twostation measurements of Rayleigh-wave group and phase velocities between Midway Atoll and O'ahu provide the basis for the test: comparison of the observed dispersion curves with age-dependent, regionalized dispersion curves suggests that the swell has the seismic velocity structure of 50-110 Myr old lithosphere rather than that of 20-50 Myr old lithosphere as suggested by the rejuvenation model. Joint inversion of the group- and phase-velocity curves for isotropic velocity models yields an estimate of - 100 km for the seismic lithosphere's thickness along the swell. This value is difficult to reconcile with the 40-50 km thickness demanded by the rejuvenation model. Preliminary measurements of the coefficients of anelastic attenuation are also presented. Although the accuracy of these values is difficult to assess, they too appear to be consistent with thick lithosphere.
Intestinal allograft survival in the rat following pretreatment with donor-specific UV-B-irradiated leukocytes and peritransplant immunosuppression with cyclosporine.

Previous studies from our laboratory showed that pretreatment with ultraviolet-B-irradiated donor leukocytes (UV-B DL) combined with brief peritransplant cyclosporine (CyA) resulted in indefinite survival of Wistar/Furth rat cardiac allografts in Lewis recipients. This study was designed to examine the effect of pretransplant UV-B DL with or without peritransplant CyA on orthotopic intestinal allografts in the same rat strain combination. The results showed that while low-dose CyA treatment alone (10 mg/kg i.m. on days 0, +1, and +2) had no effect on intestinal allograft rejection, 20 mg/kg (on days 0, +1, and +2) CyA significantly (P≤0.001) prolonged graft survival, with 33% of the hosts surviving indenfinitely. The highest dose of CyA (30 mg on days 0, +1, and +2) abrogated rejection, but most transplant recipients succumbed to infection and functional ileus due to a toxic side effect of CyA. Pretreatment with UV-B DL on days -14 and-7 alone did not prolong intestinal allograft survival. Combination of a subtherapeutic CyA dose (20 or 10 mg/kg) given on days 0, +1, and +2 with pretransplant UV-B DL on days-14 and -7 did not alter the survival of intestinal allografts compared to treatment with CyA alone. This suggests that pretreatment with UV-B DL with or without peritransplant administration of CyA has no effect on intestinal allograft survival, in contrast to the effect of such combined treatment on cardiac allograft survival, where indefinite graft survival is observed. This difference in the effect of pretransplant UV-B DL on intestinal and cardiac allograft survival is most likely due to organ-specific immunogenicity, particularly to the relative density of class I and II histocompatibility antigens present in heart or intestine.
Spin-spin correlations in the two-dimensional ising model

The Onsager solution to the two-dimensional Ising model is phrased in the language of thermodynamic Green’s functions. The description is quite closely analogous to a theory of noninteracting fermions, except that displacements along one of the lattice directions replace the time displacements of the standard fermion theory. This formulation is used to provide new derivations of the well-known results for the partition function and the zero-field magnetization. Aside from these formulational points, the main new result of this paper is an evaluation of the spin-spin correlation function in the limit of large, but not infinite, spatial separations between the spins. For the square lattice with nearest neighbor interactions and all coupling constants identical, the correlation functions respectively forT just greater than or just less thanTc are shown to be of the form\(\left\langle {[\sigma _{j_1 ,k_1 } - \left\langle \sigma \right\rangle ][\sigma _{j_2 ,k_2 } - \left\langle \sigma \right\rangle ]} \right\rangle = \varepsilon ^{1/4} f \gtrless (\varepsilon R),\), wheree=4|K−Kc| is a measure of the distance from the critical temperature andR=[(j1−j2)2+(k1−k2)2]1/2 is the spatial separation of the spin sites. This result holds whene→0 buteR remains finite. The functionsf(x) are evaluated in the asymptotic limit of largex and shown to be\(f (x) = e^{ - x} (\pi x)^{ - 1/2} 2^{ - 3/8} \).
Wing Vertical Position Effects on Wing-Body Carryover for Noncircular Missiles

The preliminary design component buildup factor KW(B), a measure of the wing-body interference caused by upwash, is investigated for unbanked, supersonic missiles with noncircular body cross section. The aerodynamic effects of wing vertical location relative to the missile fuselage centerline, Mach number, and fuselage cross-sectional shape are parametrically varied to develop a preliminary design data base of KWW values for circular, square, and triangular missile bodies. A spatial marching Euler code ZEUS is used to determine the delta-wing normal force in the presence of the body. Euler KW{B} predictions are compared to the slender body theory presently used for computing low angle-of-attack KW(B} in missile preliminary design engineering methods. Euler values of KW(B) exhibit sensitivity to wing vertical position, Mach number, and body cross-sectional shape, whereas slender body theory is a function of wing semispan to body radius ratios, SIR, only. Euler values of KW(B) are generally found to differ from slender body theory values by less than 15% for smaller S/R9 and they approach slender body theory values at larger SIR.
The Maya and the Gringos Many “Unfinished Conversations”

Unfinished Conversations: Maya and Foreigners between Two Wars. Paul Sullivan. Berkeley:University of California Press, 1991. 269 pp. $12.95 (paper). ISBN 0–520–07244–8. Deserted Cities of the Heart. Lewis Shiner. New York: Bantam, 1991. 352 pp. $4.50 (paper). ISBN 0–553–35457–4. Gringos. Charles Portis. New York: Simon and Schuster, 1991. 278 pp. $18.95 (cloth). ISBN 0–67172–457–6. The Long Night of White Chickens. Francisco Goldman. New York: Atlantic Monthly Press, 1992. 450 pp. $12.00 (paper). ISBN 0–87113–541–8.
Optical second harmonic study of Sb adsorption on Ge(111)

Abstract The adsorption of Sb on Ge(111) has been examined by optical second harmonic generation (SHG) in combination with low-energy electron diffraction, Auger spectroscopy, and temperature programmed desorption (TPD). Adsorption at room temperature yields a layer that must be annealed to at least 675 K in order to relax the adsorbate to an equilibrium configuration. This relaxed layer forms an ideally terminated (1 × 1) structure with a saturation coverage θ Sb of one monolayer. TPD indicates that Sb desorbs with an activation energy E D = 65 kcal/mol, which is similar to the heat of vaporization of bulk Sb. SHG measurements show that the nonlinear susceptibility χ (2) xxx changes sign at θ Sb = 0.48. Such an effect has never been reported previously, and indicates that Sb induces substantial charge redistribution in the top layers of Ge.
HydF as a scaffold protein in [FeFe] hydrogenase H-cluster biosynthesis

In an effort to determine the specific protein component(s) responsible for in vitro activation of the [FeFe] hydrogenase (HydA), the individual maturation proteins HydE, HydF, and HydG from Clostridium acetobutylicum were purified from heterologous expressions in Escherichia coli. Our results demonstrate that HydF isolated from a strain expressing all three maturation proteins is sufficient to confer hydrogenase activity to purified inactive heterologously expressed HydA (expressed in the absence of HydE, HydF, and HydG). These results represent the first in vitro maturation of [FeFe] hydrogenase with purified proteins, and suggest that HydF functions as a scaffold upon which an H-cluster intermediate is synthesized.
Research: Communication among real-time objects using the HU-DF inter-process-group communication scheme

A highly desired property in complex real-time distributed computer systems (DCSs) is autonomy of the various subsystems that compose the DCS. Highly autonomous subsystems enable concurrent and largely independent testing/verification and maintenance of the subsystems. In recent years, we have formulated two system structuring techniques which could be used as basic tools for enhancing the subsystem autonomy: (1) the RTO.k object structuring scheme and (2) the Hitachi-UCI (HU) Data Field (DF) inter-process-group communication scheme. A symbiotic relationship that can be established between these two techniques is the main theme of this paper. The RTO.k object structuring scheme has been devised to enable the realization of real-time computing in the form of a generalization of non-real-time computing and yet allow system engineers to confidently produce certifiable real-time DCSs. The HU-DF scheme enables the enhancement of the object autonomy, especially the relocation autonomy and the data acceptance autonomy. In this paper, we present the major techniques adopted in the implementation of support facilities for inter-RTO method communication using the HU-DF scheme in an operating system kernel model named the DREAM kernel. The DREAM kernel of which a prototype implementation is used in several research organizations, can support both conventional real-time processes and RTO.k objects with guaranteed timely services. The implementation techniques presented here are believed to be amenable to easy adaptation for a variety of system environments aimed to facilitate highly decentralized real-time computer applications.
Identifying and defusing weapons of mass inflammation in carcinogenesis

The continued cancer risks associated with chronic inflammation necessitate the identification of inflammatory molecules and the cancer pathways they affect. Evidence indicates that there are multiple mechanisms linking inflammation to cancer and that there are multiple targets for chemoprevention. Here, we review some of the key factors and the cancer pathways they disturb as a necessary prerequisite to the identification of targets for chemoprevention.
A constitutive relation describing dilatant behavior in Climax Stock granodiorite

Abstract Climax Stock granodiorite was compressively loaded along different paths to failure at a fixed strain rate and at mean pressures to 0.7 GPa. These data are used to develop a constitutive relation. The expression relates dilatant volume strain ϵd to mean pressure P and shear stress τ in the form: ϵ d =exp δP x (τ) − A (τ) where x and A are explicit functions of τ. The equation has the advantage of simplicity and of expressing the actual behavior in terms of measured physical parameters.
The fate and effects of Salmonella flagellin in neonatal rat intestine.

Nachweis, dass intestinal appliziertes I125 markiertesSalmonella Flagellin in Ratten, bis zum Alter von 5 Tagen, antigen wirkt. Die Aufnahme des Flagellins im Ileum erfolgt uber vakuolare Zellen der Mucosa.
EARLY SURGERY REDUCES MORTALITY IN PATIENTS WITH INFECTIVE ENDOCARDITIS: INSIGHT FROM A META–ANALYSIS

The effect of early surgical intervention on mortality in patients with infective endocarditis (IE) remains controversial. We conducted a systematic review and meta–analysis of available studies to evaluate the clinical outcome of early surgery compared with conventional medical therapy or
Wave equation migration with the phase-shift method

Accurate methods for the solution of the migration of zero-offset seismic records have been developed. The numerical operations are defined in the frequency domain. The source and recorder positions are lowered by means of a phase shift, or a rotation of the phase angle of the Fourier coefficients. For applications with laterally invariant velocities, the equations governing the migration process are solved very accurately by the phase-shift method. The partial differential equations considered include the 15 degree equation, as well as higher order approximations to the exact migration process. The most accurate migration is accomplished by using the asymptotic equation, whose dispersion relation is the same as that of the full wave equation for downward propagating waves. These equations, however, do not account for the reflection and transmission effects, multiples, or evanescent waves. For comparable accuracy, the present approach to migration is expected to be computationally more efficient than finite-difference methods in general.
Allele- and haploid-specific product generated by alternative splicing from a mouse t complex responder locus candidate

Mouse t haplotypes represent a variant form of chromosome 17 that has evolved the ability to propagate through natural populations by the phenomenon of 'transmission ratio distortion' (TRD), in which heterozygous +/t males transmit their t-carrying chromosome to 95% or more of their offspring. Although multiple t-associated loci have a role in expression of this phenotype, only one--the t complex responder (Tcr) locus--is responsible for determining which of the two homologues of chromosome 17 will be transmitted at a high ratio. A candidate gene (Tcp-10b) for Tcr that is expressed in both meiotic and post-meiotic male germ cells has been cloned. But for this candidate gene to function as the haploid effector of TRD, the t-allele of this gene (Tcp-10bt) must express a unique product in a haploid-specific manner. Here we show that a change in the splicing pattern of Tcp-10bt transcripts occurs during sperm differentiation. This change results in a unique allele-specific and haploid-specific transcript which could encode a variant polypeptide that would fulfil the conditions required of the Tcr effector of TRD.
Response to Lenglinger

To the Editor: We thank Lenglinger for the comments (1) regarding our paper (2). Clearly, our current strategy for screening and subsequent surveillance is not highly effective. On account of the lack of randomized controlled trials, the screening, surveillance, and management of uncomplicated Barrett's esophagus are controversial. For all interventions, including population-based screening of at-risk patients and ablation and anti-reflux surgery for non-dysplastic tissue, there needs to be a balance of cost, efficacy, and potential risks. In addition, more data on the complications and long-term outcome of ablation of Barrett's epithelium without dysplasia are required.
Designing information literacy: teaching, collaborating and growing

Purpose – The purpose of this paper is to provide a methodology for the development of a plan to incorporate information literacy education into interior design programs in higher education.Design/methodology/approach – After providing background information about the role of the liaison to the interior design department, the process of the project implementation is described in detail. The project demonstrates how students learned to move beyond a mere ability to access information.Findings – The project demonstrated that in order for students to acquire critical thinking skills, both librarian and faculty must determine what skills the students should master throughout their program. Students' work showed that information literacy produces better results when it is applied in stages and with objects that build on previous skills.Originality/value – The research fills a gap in the published literature, which offers limited resources on how information literacy is taught, used and assessed in the interior...
Explicit modeling of dilation, asperity degradation and cyclic seating of rock joints

Abstract This paper presents another development in the discrete element simulation of joint behavior, namely, an appropriate formulation of dilation, asperity degradation, and seating during cyclic motion associated with earthquake and explosive excitation. Nonassociated plasticity is assumed during sliding along local asperity surfaces, however, this causes dilation to occur for the overall joint. The most significant advance is the addition of a continuity condition, the β factor, for normal displacements during joint sliding over local roughness (or asperities) to control seating or bulking during cyclic shear when asperities are degraded or damaged. Three numerical examples are presented to illustrate model calibration and implications for rock mass behavior. The first example involves simulation of a laboratory cyclic direct shear test performed on an artificially-produced tension joint in sandstone. The second example demonstrates use of the seating/bulking parameter, β, to explicitly control continuity of normal displacements for the overall joint. Parameter studies indicate that the value of β should be close to zero and can be uniquely identified from laboratory shear test results. The third example simulates response of a cavern within a moderately jointed rock mass, with and without joint roughness, when subjected to cyclic excitation.
Pulsed high-energy radiographic machine emitting x-rays (PHERMEX) flash radiographic camera

Advanced in solid state detectors and dense scintillators make radiographic cameras competitive with film in applications where the SNR is dominated by quantum statistics. In addition, these cameras offer the advantage of sub-microsecond time-gating required by present and future radiographic facilities (e.g. PHERMEX, and DARHT). We compare theoretical considerations in camera systems incorporating lens, and fiber coupling to MCPs, and CCDs. We also present Monte-Carlo blur calculations for various candidate scintillators and discuss the relative merits of the PHERMEX camera design.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Relationship between intravenous use and achieving initial cocaine abstinence

This study assessed whether route of cocaine administration (intravenous vs. intranasal) influences cocaine abstinence during the first 6 weeks of outpatient treatment. Fifty-nine persons received behavioral treatment or standard drug counselling in an outpatient clinic. Based on information collected at intake, intravenous users had fewer years of education, were employed in less skilled jobs, were less likely to be married, reported more negative consequences from cocaine use, reported using more cocaine per occasion and spent more money on cocaine per week than intranasal users. Intravenous and intranasal users did not differ significantly in the average duration of continuous cocaine abstinence (X = 2.6 vs. X = 3.3 weeks achieved during 6 weeks of treatment). The duration of abstinence between intravenous and intranasal users was equal in the behavioral treatment (X = 4.2). In standard treatment the average duration was less among intravenous than intranasal users (X = 0.9 vs. X = 2.4), but that difference did not achieve statistical significance. Hepatitis and employment instability were associated with shorter periods of cocaine abstinence among intravenous users, whereas employment instability, lower job skill level, drug use severity and reports of memory loss were associated with shorter periods of cocaine abstinence among intranasal users. These results indicate that i.v. cocaine users can achieve a period of initial abstinence in an outpatient setting comparable to the duration of typical inpatient hospitalizations, although special types of outpatient treatment may be necessary to obtain a positive outcome.
Bacteriologic status of the root canal after sonic, ultrasonic and hand instrumentation.

The purpose of this study was to assess the bacteriologic status of the root canal after sonic, ultrasonic and hand instrumentation. Root canal infection was induced in 50 single-rooted teeth in young dogs by removing the pulp and filling the canals with dental plaque. After 7 clays the root canals were instrumented under aseptic conditions with conventional hand instruments, a sonic vibratory device or an ultrasonic device. Sterile saline or 2.5% sodium hypochlorite was used as irrigating solution. Following instrumentation a sterile paper point was sealed into the root canals. After 7 d the root canals were reopened under aseptic conditions and the paper points were incubated for the demonstration of bacteria, using pre-reduced thioglycolate culture medium and anaerobic chambers. The results obtained with the different instrumentation techniques and irrigating solutions were compared by means of the Chi-square test. The results indicated that the sonic and ultrasonic devices were not more effective in the elimination of bacteria from the root canal than conventional hand instrumentation. Irrigation with sodium hypochlorite appeared to be more effective than saline in producing bacteria-free root canals; however, this difference was not statistically significant. Thus, it appeared that more than one appointment and the supporting action of an antibacterial medicament between appointments would be necessary to achieve bacteria-free root canals in infected teeth in a predictable manner.
Adding head tracking to desktop virtual reality with the Wii remote as an aid to spatial cognition

Desktop virtual reality (VR) provides a more economical and ubiquitous way to present virtual reality to people, at the cost of a significant amount of immersion. Our study explores the addition of a low-cost head-tracking system to a desktop VR system and its impact on spatial cognition. The head-tracking system is used to provide a more 3D-like interface to VR by providing parallax and allowing user access to a larger visual field than is provided by the limited viewing angle of the display monitor. Such an interface, while not providing a full set of vestibular cues, may provide enough additional information to improve spatial learning.
The general solution to the Bloch equation with constant rf and relaxation terms: Application to saturation and slice selection

The general solution to the Bloch equation in the rotating frame which includes the effects of relaxation during a constant amplitude, off-resonance rf field has been developed. The solution is used to monitor the transient approach to steady-state saturation levels during off-resonance irradiation applied continuously or in pulses to systems with arbitrary relaxation rates. The time course of the magnetization during amplitude modulated rf pulses is followed with the general solution and the transverse relaxation time dependence of typical slice profiles is examined. The calculations serve to illustrate the generality of the solution. A thorough discussion of various computational concerns is provided.
Asymptotic stability and estimating the region of attraction for the swing equatons

Abstract We state and prove a theorem that asserts the asymptotic stability and provides an estimate of the region of attraction of an equilibrium point of the swing equations. A version of this theorem was originally introduced by Willems; however, his justifications are sketchy and, in our opinion, require additional analysis. All the Liapunov method analyses utilized in the transient stability problem of power systems have been based on the assumed validity of this theorem. The shortcomings of the other proposed proofs in the literature is that they rely on available Liapunov theorems for which an assumption can not be verified. In contrast, the techniques used in the proof here avoid the restriction of the available Liapunov theorems; moreover, they can be extended to apply to a broader class of systems.
Anecdotal episodes in the social context

This article examines poor, moderate and good anecdotal episodes in the social context. The research results suggest 1) the quality of anecdotal episodes is discriminated on the basis of energy and clarity concepts rather than the traditional delivery and content perspective, and 2) the energy and clarity of anecdotal episodes are related to observer's perceived social attraction and projected potential to achieve social and professional success. Tnese results suggest that anecdotal episodes merit further consideration in relational development research from the communication perspective.
Drought frequency in central California since 101 B.C. recorded in giant sequoia tree rings

Well replicated tree-ring width index chronologies have been developed for giant sequoia at three sites in the Sierra Nevada, California. Extreme low-growth events in these chronologies correspond with regional drought events in the twentieth century in the San Joaquin drainage, in which the giant sequoia sites are located. This relationship is based upon comparison of tree-ring indices with August Palmer Drought Severity Indices for California Climate Division 5. Ring-width indices in the lowest decile from each site were compared. The frequency of low-growth events which occurred at all three sites in the same year is reconstructed from 101 B.C. to A.D. 1988. The inferred frequency of severe drought events changes through time, sometimes suddenly. The period from roughly 1850 to 1950 had one of the lowest frequencies of drought of any one hundred year period in the 2089 year record. The twentieth century so far has had a below-average frequency of extreme droughts.
Educational Needs of Juvenile Offenders

Abstract Issues and research concerning the assessment and education of incarcerated juvenile offenders are presented. Special needs and problems of this population are summarized, programs and offender characteristics are examined, and an evaluation outline is suggested. A specific evaluation model is proposed for use in juvenile educational programming. Additionally, program issues, resources, and suggestions concerning other practical issues are offered. Creative attention should be given to reading and the consideration of phonics instruction. Other creative ideas are suggested to motivate learning behaviors within this difficult population.
Preflare energy build-up in a filament circuit

The two-dimensional Van Tend and Kuperus (1978) scenario for pre-flare energy build-up is extended to a fully three-dimensional model and applied to the 16 May, 1981 flare observed at Debrecen. It is shown that there is plenty of free energy (1033 erg) available to explain the ensuing large two-ribbon flare. This estimate is an order of magnitude larger than the simple estimate made by Van Tend, as a result of the three-dimensional character of the present model. It is further confirmed that the global form of the preflare circuit is decisive for determining the amount of energy stored in the preflare configuration, while the internal structure of the filament is of little importance. This is in accordance with the similar claims of Alfven and Van Tend and Kuperus. Order of magnitude estimates are derived for all the lumped circuit parameters of the preflare filament-return current circuit; self-inductance, resistance, current strength, and applied voltage. It is found that the model gives correct predictions for the independently observed photospheric flow velocity and current strength in filaments.
Plasma pentazocine radioimmunoassay

A sensitive and specific radioimmunoassay of dog and human plasma pentazocine is described. Rabbit antiserum and the second antibody method separated bound from free pentazocine. The radioimmunoassay employed an 125I-labeled radioligand and required extraction from the sample prior to quantitation. The method had a detection limit of approximately 200 pg/assay tube (1 ng/ml). The assay was used successfully to measure pentazocine in the plasma of beagle hounds given 0.3 mg of pentazocine/kg iv. The decline in plasma levels fitted a two-compartment body model with a 100-min mean overall half-life and a 3.2-liters/hr mean plasma clearance rate.
Material variability and performance predictions on an active composite panel

Finite element analysis was performed on the preliminary design of a multilayered composite panel for acoustic suppression. The panel design features a circuit board, alumina and circuit board base layer structure. An square array of 64 piezoelectric actuators is mounted on this base. These actuators are divided into 16 groups of four actuators by 16 alumina cap plates. A thin kapton layer is placed over the cap layer. The final top layer and the area between actuators are a polymer filler material. Unit cell analysis of the design was performed to evaluate the effectiveness of the embedded actuators in producing surface deformations, the stresses generated in the actuator during actuation and the role of a thin glue layer, between the actuator and alumina cap plate, in mitigating high stresses. The results show that the cap plates become curved during deformation. This deformation is transmitted through the top polymer layer to the surface. This suggests that the effect of this surface profile on acoustic fields generated by the actuator array motion should be understood. Stresses in the actuator are found to be high without the glue layer, compared to known critical fracture stress values. Inclusion of the glue layer significantly reduced the stresses and is therefore an important consideration in the design.
Measures of adiposity and cardiovascular disease risk factors.

Objective: To determine which of five measures of adiposity maintains the strongest association with cardiovascular disease risk factors. Research Methods and Procedures: A nationally representative sample of 12,608 adult participants of the third National Health and Nutrition Examination Survey were examined. Waist circumference, total body fat, percent body fat, BMI, and skinfold thickness were measured following a standardized protocol. Results: In multivariable adjusted models including waist circumference and BMI as independent variables, waist circumference was a significantly better predictor. The odds ratios (95% confidence intervals) for each standard deviation higher waist circumference and BMI for men were as follows: 1.88 (1.43, 2.48) and 0.99 (0.76, 1.29), respectively, for hypertension; 1.51 (0.87, 2.59) and 1.23 (0.76, 1.99), respectively, for diabetes; and 1.85 (1.48, 2.32) and 1.00 (0.80, 1.24), respectively, for low high-density lipoprotein-cholesterol. The analogous odds ratios (95% confidence intervals) for women were as follows: 2.28 (1.74, 3.00) and 0.91 (0.69, 1.19), respectively, for hypertension; 2.72 (1.85, 4.00) and 0.82 (0.55, 1.23), respectively, for diabetes; and 1.90 (1.47, 2.47) and 1.07 (0.83, 1.38), respectively, for low high-density lipoprotein-cholesterol. Results were markedly similar for waist circumference in models adjusting for total body fat, percent body fat, and skinfold thickness separately. In contrast, waist circumference was not a significantly better predictor of elevated C-reactive protein than the other measures of adiposity. Discussion: Waist circumference maintains a stronger association with cardiovascular disease risk factors than other measures of adiposity.
Comparative Effects of Nutrition on the Bone Density of Dentulous and Edentulous Individuals

An analysis was made of the diet of individuals grouped according to oral condition. There was no significant difference in their nutritional state as determined by a radiographic bone density study.
Satellite attitude determination from celestial sightings.

An iterative least-squares method has been developed to estimate the attitude of an earth satellite by using the information from celestial sightings taken with onboard telescopes. The derivation of the algorithm involves the selection of a particular combination of working coordinate frames and linearization techniques that lead to very high accuracy. The high accuracy results from the situation that as the predicted attitude approaches the true attitude, the linearization error approaches zero. An application of the algorithm to particular satellite systems is discussed, taking into consideration the quantization of the measurement, the presence of the noise, and the nonlinear behavior of the vehicle axes. HE attitude determination problem for satellites arises from the limited capability of attitude-cont rol systems aboard. Rather than increasing the attitude-control-system precision, it is often less expensive to install reliable star sensors in the vehicle and to determine the actual attitude from data gathered through those sensors. Of course, it is necessary for the star sensor systems to be capable of recognizing and identifying a sufficient number of stars, and to determine their observed sighting directions with sufficient
Measurement of inelastic electron impact on ozone: Absolute differential cross sections for excitation of the Hartley band

By means of a crossed-beam technique, we have conducted absolute differential cross-section measurements for the excitation of ozone{close_quote}s Hartley band by electron impact. The angular range covered was from 12{degree} to 156{degree}, while the impact energies employed were 7, 10, 15, and 20 eV. The angular distributions indicate that the Hartley band has a composite nature, arising from at least one optically allowed and at least one optically forbidden transition. Candidates for these transitions are indicated with help from the results of theoretical calculations. Unfortunately, aside from the well known 1{sup 1}{ital B}{sub 2}{l_arrow}{ital X}{sup 1}{ital A}{sub 1} allowed transition observed in optical spectra, definitive assignments for these transitions cannot yet be made. Integrated cross sections were calculated from the measured differential cross sections. The former exhibit a maximum near 15-eV impact. {copyright} {ital 1996 The American Physical Society.}
Development of a Mach 18 quiet helium tunnel for transition research

A new 'quiet' tunnel, the Mach 18 quiet helium tunnel has been developed to support research on transition estimation in hypersonic flows. An existing facility has been modified to provide low-disturbance flow for transition research in a conical nozzle with an exit Mach number of about 18. This paper describes tunnel modifications, unique features, and operating parameters. The tunnel will be used primarily for the validation of boundary-layer stability codes and includes a 1 micron flow filter, a new inlet diffuser, several flow conditioning elements, a conical nozzle, and a boundary-layer bleed system.
Psychophysiological Responses to Background Brand Placements in Video Games

Researchers have typically employed cognitive and affective measures to study the effectiveness of brand placements in video games. A psychophysiological approach to measuring effectiveness has been sorely lacking and is necessary to help both academics and practitioners further their understanding of how brand placements work. The current study measures individuals’ orienting responses in terms of increased skin conductance and decreased heart rate upon exposure to brands in video games. Results indicate that game players register background advertisements subconsciously even though they may not be able to explicitly recall them later. There were no differences between gamers and nongamers in the recall and recognition of brands from the video game. Furthermore, brands with preexisting favorable attitudes automatically received further processing, suggesting orienting response is an indicator of initial perception rather than further elaboration.
Methodological issues in drug assessment research

Increased sensitivity to methodological issues in drug assessment research is needed in light of challenges to research design, conduct, and outcomes. Major issues presented include (a) the nature and adequacy of placebo controls, (b) problems in maintaining the integrity of “blind” conditions, and (c) the potential design-compromising effects of informed consent. The necessity of true matching placebos, particularly concerning physical/perceptual characteristics and the ability to produce transitory changes in subjects, was stressed. Though the double-blind condition has conceptual integrity, the operation of drug and placebo side effects and associated guess bias may confound research results. Use of a triple-blind condition and addition of a drug-disguised group is suggested. Last, the issue of informed consent and its implications for the integrity of drug research is a problem deserving more attention.
Femtosecond Studies on 5CB and 8CB Liquid Crystals

In this study we report pump-probe femtosecond spectroscopy on 5CB and 8CB liquid crystals at different phase transitions. Also, molecular dynamic calculations of the liquid crystal vibrational modes will be presented using Gaussian 09 software.
The design of a configurable, extensible and dynamic notification service

Publish/subscribe infrastructures, specifically notification servers, are used in a large spectrum of distributed applications as their basic communication and integration infrastructure. With their recent popularization, notification servers are being developed to support specific application domains. At the same time, general-purpose notification servers provide a large set of functionality for a broad set of applications. With so many options, developers face the dilemma of choosing between application-specific or general-purpose notification servers. In both cases, however, the set of features provided by the servers are usually neither extensible nor configurable, making their customization to specific application domains a difficult task. In this work, a more flexible approach is proposed - a customizable, extensible and dynamic architecture for notification services - which allows the customization of the notification service to different application domains. The extensi-bility model is presented according to the design framework proposed by Rosemblum and Wolf. A preliminary implementation of the prototype is also discussed, as well as configuration examples.