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Summary Background Spinal anesthesia (SA) is an established anesthetic technique for short outpatient pediatric urological cases. To avoid general anesthesia (GA) and expand regional anesthetics to longer and more complex pediatric surgeries, the authors began a program using a combined spinal/caudal catheter (SCC) technique. Study design The authors retrospectively reviewed the charts of all patients scheduled for surgery under SCC between December 2016 and April 2018 and recorded age, gender, diagnosis, procedure, conversion to GA/airway intervention, operative time, neuraxial and intravenous medications administered, complications, and outcomes. The SCC technique typically involved an initial intrathecal injection of 0.5% isobaric bupivacaine followed by placement of a caudal epidural catheter. At the discretion of the anesthesiologist, patients received 0.5 mg per kilogram of oral midazolam approximately 30 min prior to entering the operating room. One hour after the intrathecal injection, 3% chloroprocaine was administered via the caudal catheter to prolong the duration of surgical block. Intra-operative management included either continuous infusion or bolus dosing of dexmedetomidine, as needed, for patient comfort and to optimize surgical conditions. Prior to removal of caudal catheter in the post-anesthesia care unit, a supplemental bolus dose of local anesthesia was given through the catheter to provide prolonged post-operative analgesia. Results Overall, 23 children underwent attempted SCC. SA was unsuccessful in three patients, and surgery was performed under GA. The remaining 20 children all had successful SCC placement. There were 11 girls and nine boys, with a mean age of 16.5 months (3.3–43.8). Surgeries performed under SCC included seven ureteral reimplantations, two ureterocele excisions/reimplantations, two megaureter repairs, four first-stage hypospadias repairs, one distal hypospadias repair, one second-stage hypospadias repair, two feminizing genitoplasties, and one open pyeloplasty. Average length of surgery was 109 min (range 63–172 min). Pre-operative midazolam was given in 13/20 (65%). All SCC patients were spontaneously breathing room air during the operation, and there were no airway interventions. Only one SCC patient received opioids intra-operatively. There were no intra-operative or perioperative complications. Discussion This pilot study shows that the technique of SCC allows one to do more complex urologic surgery under regional anesthesia than what would be possible under pure SA alone. The main limitations of the study include the relatively small number of patients and the small median length of the operative procedures. As a proof of concept, however, this does show that complex genital surgery bladder level procedures such as ureteral reimplantation can be performed under regional anesthesia. Conclusion SCC allows for more complex surgeries to be performed exclusively under regional anesthesia, thus obviating the need for airway intervention, minimizing or eliminating the use of opioids, and thus avoiding known and potential risks associated with GA. The latter is of particular importance given current concerns regarding hypothetical neurocognitive effects of GA on children aged below 3 years. Download : Download high-res image (389KB) Download : Download full-size image Summary Figure .

Background: Efforts to establish the 2015 baseline and monitor early implementation of the UN Sustainable Development Goals (SDGs) highlight both great potential for and threats to improving health by 2030. To fully deliver on the SDG aim of “leaving no one behind”, it is increasingly important to examine the health-related SDGs beyond national-level estimates. As part of the Global Burden of Diseases, Injuries, and Risk Factors Study 2017 (GBD 2017), we measured progress on 41 of 52 health-related SDG indicators and estimated the health-related SDG index for 195 countries and territories for the period 1990–2017, projected indicators to 2030, and analysed global attainment. Methods: We measured progress on 41 health-related SDG indicators from 1990 to 2017, an increase of four indicators since GBD 2016 (new indicators were health worker density, sexual violence by non-intimate partners, population census status, and prevalence of physical and sexual violence [reported separately]). We also improved the measurement of several previously reported indicators. We constructed national-level estimates and, for a subset of health-related SDGs, examined indicator-level differences by sex and Socio-demographic Index (SDI) quintile. We also did subnational assessments of performance for selected countries. To construct the health-related SDG index, we transformed the value for each indicator on a scale of 0–100, with 0 as the 2·5th percentile and 100 as the 97·5th percentile of 1000 draws calculated from 1990 to 2030, and took the geometric mean of the scaled indicators by target. To generate projections through 2030, we used a forecasting framework that drew estimates from the broader GBD study and used weighted averages of indicator-specific and country-specific annualised rates of change from 1990 to 2017 to inform future estimates. We assessed attainment of indicators with defined targets in two ways: first, using mean values projected for 2030, and then using the probability of attainment in 2030 calculated from 1000 draws. We also did a global attainment analysis of the feasibility of attaining SDG targets on the basis of past trends. Using 2015 global averages of indicators with defined SDG targets, we calculated the global annualised rates of change required from 2015 to 2030 to meet these targets, and then identified in what percentiles the required global annualised rates of change fell in the distribution of country-level rates of change from 1990 to 2015. We took the mean of these global percentile values across indicators and applied the past rate of change at this mean global percentile to all health-related SDG indicators, irrespective of target definition, to estimate the equivalent 2030 global average value and percentage change from 2015 to 2030 for each indicator. Findings: The global median health-related SDG index in 2017 was 59·4 (IQR 35·4–67·3), ranging from a low of 11·6 (95% uncertainty interval 9·6–14·0) to a high of 84·9 (83·1–86·7). SDG index values in countries assessed at the subnational level varied substantially, particularly in China and India, although scores in Japan and the UK were more homogeneous. Indicators also varied by SDI quintile and sex, with males having worse outcomes than females for non-communicable disease (NCD) mortality, alcohol use, and smoking, among others. Most countries were projected to have a higher health-related SDG index in 2030 than in 2017, while country-level probabilities of attainment by 2030 varied widely by indicator. Under-5 mortality, neonatal mortality, maternal mortality ratio, and malaria indicators had the most countries with at least 95% probability of target attainment. Other indicators, including NCD mortality and suicide mortality, had no countries projected to meet corresponding SDG targets on the basis of projected mean values for 2030 but showed some probability of attainment by 2030. For some indicators, including child malnutrition, several infectious diseases, and most violence measures, the annualised rates of change required to meet SDG targets far exceeded the pace of progress achieved by any country in the recent past. We found that applying the mean global annualised rate of change to indicators without defined targets would equate to about 19% and 22% reductions in global smoking and alcohol consumption, respectively; a 47% decline in adolescent birth rates; and a more than 85% increase in health worker density per 1000 population by 2030. Interpretation: The GBD study offers a unique, robust platform for monitoring the health-related SDGs across demographic and geographic dimensions. Our findings underscore the importance of increased collection and analysis of disaggregated data and highlight where more deliberate design or targeting of interventions could accelerate progress in attaining the SDGs. Current projections show that many health-related SDG indicators, NCDs, NCD-related risks, and violence-related indicators will require a concerted shift away from what might have driven past gains—curative interventions in the case of NCDs—towards multisectoral, prevention-oriented policy action and investments to achieve SDG aims. Notably, several targets, if they are to be met by 2030, demand a pace of progress that no country has achieved in the recent past. The future is fundamentally uncertain, and no model can fully predict what breakthroughs or events might alter the course of the SDGs. What is clear is that our actions—or inaction—today will ultimately dictate how close the world, collectively, can get to leaving no one behind by 2030. Funding: Bill & Melinda Gates Foundation. © 2018 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license

The bulk of aqueous humor passing through the conventional outflow pathway must cross the inner wall endothelium of Schlemm's canal (SC), likely through micron-sized transendothelial pores. SC pore density is reduced in glaucoma, possibly contributing to obstructed aqueous humor outflow and elevated intraocular pressure (IOP). Little is known about the mechanisms of pore formation; however, pores are often observed near dome-like cellular outpouchings known as giant vacuoles (GVs) where significant biomechanical strain acts on SC cells. We hypothesize that biomechanical strain triggers pore formation in SC cells. To test this hypothesis, primary human SC cells were isolated from three non-glaucomatous donors (aged 34, 44 and 68), and seeded on collagen-coated elastic membranes held within a membrane stretching device. Membranes were then exposed to 0%, 10% or 20% equibiaxial strain, and the cells were aldehyde-fixed 5 min after the onset of strain. Each membrane contained 3-4 separate monolayers of SC cells as replicates (N = 34 total monolayers), and pores were assessed by scanning electron microscopy in 12 randomly selected regions (∼65,000 μm(2) per monolayer). Pores were identified and counted by four independent masked observers. Pore density increased with strain in all three cell lines (p 0.010), increasing from 87 ± 36 pores/mm(2) at 0% strain to 342 ± 71 at 10% strain; two of the three cell lines showed no additional increase in pore density beyond 10% strain. Transcellular "I-pores" and paracellular "B-pores" both increased with strain (p 0.038), however B-pores represented the majority (76%) of pores. Pore diameter, in contrast, appeared unaffected by strain (p = 0.25), having a mean diameter of 0.40 μm for I-pores (N = 79 pores) and 0.67 μm for B-pores (N = 350 pores). Pore formation appears to be a mechanosensitive process that is triggered by biomechanical strain, suggesting that SC cells have the ability to modulate local pore density and filtration characteristics of the inner wall endothelium based on local biomechanical cues. The molecular mechanisms of pore formation and how they become altered in glaucoma may be studied in vitro using stretched SC cells.

A second-generation toroidal spectrometer has been used to investigate the Fermi surface topology of the binary alloy system Cu 3 Au when prepared as an ordered or substitutionally disordered alloy. We demonstrate using two complementary Fermi surface mapping techniques and an empirical FS model for the disordered phase, that structures in the data arise from two different mechanisms. We observe distinct effects on the FS upon ordering, and compare the results with a recent bandstructure calculation.

Cell-wall mechanical properties play an integral part in the growth and form of Saccharomyces cerevisiae . In contrast to the tremendous knowledge on the genetics of S. cerevisiae , almost nothing is known about its mechanical properties. We have developed a micromanipulation technique to measure the force required to burst single cells and have recently established a mathematical model to extract the mechanical properties of the cell wall from such data. Here we determine the average surface modulus of the S. cerevisiae cell wall to be 11.1 ± 0.6 N/m and 12.9 ± 0.7 N/m in exponential and stationary phases, respectively, giving corresponding Young's moduli of 112 ± 6 MPa and 107 ± 6 MPa. This result demonstrates that yeast cell populations strengthen as they enter stationary phase by increasing wall thickness and hence the surface modulus, without altering the average elastic properties of the cell-wall material. We also determined the average breaking strain of the cell wall to be 82% ± 3% in exponential phase and 80% ± 3% in stationary phase. This finding provides a failure criterion that can be used to predict when applied stresses (e.g., because of fluid flow) will lead to wall rupture. This work analyzes yeast compression experiments in different growth phases by using engineering methodology.

In the preceding paper (Part I) force-deformation data were measured with the compression experiment in conjunction with the initial radial stretch ratio and the initial wall-thickness to cell-radius ratio for baker's yeast (Saccharomyces cerevisiae). In this paper, these data have been analysed with the mechanical model of Smith et al. (Smith, Moxham & Middelberg (1998) Chemical Engineering Science, 53, 3913-3922) with the wall constitutive behaviour defined a priori as incompressible and linear-elastic. This analysis determined the mean Young's modulus ((E) over bar), mean maximum von Mises stress-at-failure (l(sigma)over barg(VM,f)) and mean maximum von Mises strain-at failure (l(epsilon)over barg(VM,f)) to be (E) over bar = 150 +/- 15 MPa, l(sigma)over barg(VM,f) = 70 +/- 4 MPa and l(epsilon)over barg(VM,f) = 0.75 +/- 0.08, respectively. The mean Young's modulus was not dependent (P greater than or equal to 0.05) on external osmotic pressure (0-0.8 MPa) nor compression rate (1.03-7.68 mu m/s) suggesting the incompressible linear-elastic relationship is representative of the actual cell-wall constitutive behaviour. Hydraulic conductivities were also determined and were comparable to other similar cell types (0-2.5 mu m/MPa s). The hydraulic conductivity distribution was not dependent on external osmotic pressure (0-0.8 MPa) nor compression rate (1.03-7.68 mu m/s) suggesting inclusion of cell-wall permeability in the mechanical model is justified. l(epsilon)over barg(VM,f) was independent of cell diameter and to a first-approximation unaffected (P greater than or equal to 0.01) by external osmotic pressure and compression rate, thus providing a reasonable failure criterion. This criterion states that the cell-wall material will break when the strain exceeds l(epsilon)over barg(VM,f) = 0.75 +/- 0.08. Variability in overall cell strength during compression was shown to be primarily due to biological variability in the maximum von Mises strain-at-failure. These data represent the first estimates of cell-wall material properties for yeast and the first fundamental analysis of cell-compression data. They are essential for describing cell-disruption at the fundamental level of fluid-cell interactions in general bioprocesses. They also provide valuable new measurements for yeast-cell physiologists. (C) 2000 Elsevier Science Ltd. All rights reserved.

A finite element model (FEM) of the cell-compression experiment has been developed in dimensionless form to extract the fundamental cell-wall-material properties (i.e. the constitutive equation and its parameters) from experiment force-displacement data. The FEM simulates the compression of a thin-walled, liquid-filled sphere between two flat surfaces. The cell-wall was taken to be permeable and the FEM therefore accounts for volume loss during compression. Previous models assume an impermeable wall and hence a conserved cell volume during compression. A parametric study was conducted for structural parameters representative of yeast. It was shown that the common approach of assuming reasonable values for unmeasured parameters (e.g. cell-wall thickness, initial radial stretch) can give rise to nonunique solutions for both the form and constants in the cell-wall constitutive relationship. Similarly, measurement errors can also lead to an incorrectly defined cell-wall constitutive relationship. Unique determination of the fundamental wall properties by cell compression requires accurate and precise measurement of a minimum set of parameters (initial cell radius, initial cell-wall thickness, and the volume loss during compression). In the absence of such measurements the derived constitutive relationship may be in considerable error, and should be evaluated against its ability to predict the outcome of other mechanical experiments. (C) 1998 Elsevier Science Ltd. All rights reserved.

A seismic acquisition on the Snorre field has been conducted in summer 2012. The Snorre field is in a very busy area of the North Sea including fishing activity, production activity and concurrent seismic acquisition. Due to tight time constrains, special care was given to the treatment of the seismic interference in order to avoid timeshare as much as possible. Ahead of the acquisition, the onboard processing sequence and the onboard QC attributes have been revisited in order to handle the seismic interference and its QC has good and as quickly as possible. During the acquisition, the onboard processing team produced QC displays of the seismic interference removal as soon as possible and made them available for remote QC. Acceptance decisions were made based on seismic interference removal QC displays, RMS displays, noise displays and near trace displays. 4D QC was also produced on a regular basis. The cooperation between the onboard processing, client representative, onshore processing and client QC made it possible to have a very short turnaround time and a very efficient acquisition. Out of the 49 sequences affected by seismic interference, 5 ended up being reshot. The survey was complete 14 days ahead of schedule.

A study of the 12 C( 24 Mg, 12 C 12 C) 12 C reaction has revealed discrete states at excitation energies between 20 and 30 MeV in 24 Mg. Angular correlation analyses of some of the lower energy states confirms the report by earlier authors of monotonically increasing spin values consistent with a rotational sequence. Comparison with breakup observed in the 12 C( 20 Ne, 12 C 12 C) 8 Be reaction suggests that the same states in 24 Mg are populated, while the difference in laboratory cross sections in the two reactions is interpreted as evidence for the association of the breakup states with a prolate hyper-deformed configuration appearing in theoretical calculations for 24 Mg.

The breakup of {sup 23}Na nuclei into {sup 11}B+{sup 12}C and of {sup 24}Mg nuclei into {sup 12}C+{sup 12}C has been studied using the reactions {sup 12}C({sup 23}Na,{sup 11}B{sup 12}C){sup 12}C and {sup 12}C({sup 23}Na,{sup 12}C{sup 12}C){sup 11}B. Clear evidence was found for the breakup of the {sup 23}Na and {sup 24}Mg nuclei into the ground states of both fragments. The yieldrotect from the {sup 12}C({sup 23}Na,{sup 11}B{sub g.s.}{sup 12}C{sub g.s.}){sup 12}C{sub g.s.} reaction was concentrated in the region of excitationrotect energy in {sup 23}Na between 24 and 28 MeV and fragmented among a number of states. Therotect {sup 12}C({sup 23}Na,{sup 12}C{sub g.s.} {sup 12}C{sub g.s.)}{sup 11}B{sub g.s.} reaction was found to proceed chiefly via broad states at 22.1 and 23.9 MeV in {sup 24}Mg.

Aqueous extracts of tissue from the test species (giant foxtail, green foxtail, yellow foxtail, bahiagrass, barnyardgrass, Johnsongrass and large crabgrass) harvested at the vegetative and mature stages were tested for allelopathy on seed germination and seedling growth of the bioassay species (alfalfa and Italian ryegrass). Tissues harvested from large crabgrass and barnyardgrass were found not to be allelopathic; only tissue harvested from the five other test species during the mature stage of plant growth exhibited allelopathic characteristics. Extracts of stem material reduced seed germination and seedling growth for both bioassay species. It was estimated that 0.30/0.33, 0.23/0.18, 0.20/0.21, 0.31/0.32 and 0.38/0.19% aqueous extracts of mature Johnsongrass, bahiagrass, giant foxtail, green foxtail and yellow foxtail stem tissue resulted in a 50% reduction in seed germination/seedling growth of Italian ryegrass, respectively. Concentrations in a similar range resulted in 50% reduction in seed germination and seedling growth in the alfalfa bioassay. The potential concentration for foliage tissue in soil solution of the pasture ecosystem for Johnsongrass, bahiagrass, giant foxtail, green foxtail, and yellow foxtail foliage tissue would be 3.2, 1.0, 2.0, 1.4 and 1.4%, respectively. The allelopathic characteristics of these species could therefore be of economic importance in the pasture ecosystem when overseeding the pasture with grass and legume species.

Corpus luteum growth and function were monitored daily for a complete estrous cycle by ultrasonography and peripheral serum progesterone in lactating, cyclic Holstein cows during spring (n = 8) and summer (n = 8). For spring and summer, respectively, daily ambient temperatures (mean +/- SEM) were 21.2 +/- .9 and 31.1 +/- .3 degrees C. In summer compared with spring, early morning rectal temperatures were higher on d 1, 2, and 3, when the corpus luteum was forming, and on d 15 and 19. The length of the luteal phase and the corpus luteum cross-sectional area were similar for the two seasonal groups. Central luteal cavities were observed during spring and summer. Serum progesterone secreted between d 6 and 18 was lower during summer. In addition, progesterone concentrations during the entire luteal phase and the peak magnitude of progesterone tended to be lower during summer. Suppressed luteal function may contribute to low fertility when cows are inseminated during summer.

A continuously variable attenuator for the CO2 laser, causing minimal degradation of beam quality, is implemented using rotating ZnSe wedges, and is capable of transmissivities between 0.3% and 18%, and between 27% and 89%. The transmissivity at any particular setting was measured to be essentially constant for wavelengths from 9.27 μm (9R20) to 10.77 μm (10P36).

The potential of InSb as a material for limiters for CO 2 laser pulses is explored. A model of the nonlinearity is presented and material parameters estimated from Z-Scans and ring-scans. This is then used to model the performance of a basic thin-sample defocussing limiter and find optimum conditions. A simple practical device for removing the gain switched peak from a TEA laser pulse is also described.

Some experimental techniques used in the measurement and analysis of inverse kinematic reactions are described and applied to a kinematically complete

A first principles calculation of the inelastic electron mean inner-potential is presented for Si and GaAs as a function of incident energy. This work is based on a dielectric matrix calculation of the frequency and wave-vector dependent loss function determined in the RPA from non-local empirical pseudopotential electronic structure. Comparisons are made with the generalised oscillator strength models and experiment.

A theoretical description of the propagation of an initially Gaussian beam through a “generalized” thin nonlinear medium is developed, where the linear part of the optical system can be characterized by an ABCD matrix. The optical field is determined on the output interface of the medium and is decomposed into Gaussian-Laguerre modes. These modes are then propagated through the optical system using the ABCD law, so that the field distribution at any point can be determined. We obtain an expression for the on-axis relative transmissivity of the combined system, which is valid for nonlinear absorption regimes to all orders of nonlinearity. The positions of the turning points of the normalized axial transmissivity as a function of the position of the medium are derived analytically to the first-order of nonlinearity. It is shown that, from measurements of these positions, the nonlinear refractive and absorptive strengths as well as the type of nonlinearity can be extracted.

There is a widespread belief that psoriasis (Ps) and atopic dermatitis (AD) are clinically mutually exclusive. A prospective study was undertaken to record the concurrent and/or consecutive coincidence of the two conditions and any shared clinical features. Patients attending a dermatology clinic were systematically examined for the presence of Ps and/or AD. Nine hundred and eighty-three patients were studied--428 with Ps, 224 with AD, 45 with both Ps and AD, and 286 controls. Of AD patients 16.7% had Ps, and 9.5% of Ps patients had AD. In consecutive occurrences, Ps generally followed AD. The ratio of concurrent to consecutive incidences was 3:1. The two diseases are shown not to be mutually exclusive and may coexist in the same individual.

Results of convergent-beam reflection high-energy electron diffraction (CB-RHEED) calculations are presented for the (111) surface of silicon. These double rocking calculations are performed using a dynamical scattering approach. This is based on evaluation of the surface parallel multislice matrix for reflection with account taken of the boundary conditions. In particular, calculations are shown for intensities close to a reflection that is kinematically forbidden. Particular note is made of the computational simulation of intensity enhancements corresponding to surface wave resonance conditions.

In several recent measurements the symmetric fission of 24 Mg has been reported. In this paper the results of a search for similar processes in 28 Si and 32 S are presented. In contrast to the results for 24 Mg, no evidence is seen for the fission of 28 Si to 16 O+ 12 C or 32 S to 16 O+ 16 O following inelastic excitation. However, these processes are observed to occur following pickup onto 24 Mg. The results are consistent with a simple model of the fission process developed by Harvey and suggest the existence of large scale cluster structure in all three nuclei.

A new high resolution measurement of the 12 C( 24 Mg, 12 C 12 C) 12 C breakup reaction has been performed. Sequential breakup is observed from specific states in 24 Mg at excitation energies ranging from 20 to 26 MeV. Angular correlation measurements indicate that states with spins ranging from J =4 to 8 are populated. These states are consistent with superdeformed shape isomeric bands predicted by cranked cluster model and Nilsson-Strutinsky calculations.

A search has been performed for large cluster breakup from 40Ca following inelastic scattering. No evidence is seen for breakup to the 12C+28Si, 16O+24Mg or 20Ne+20Ne channels.

Laboratory and growth chamber research was conducted to determine the potential allelopathy of tissue harvested from certain weeds commonly found in pastures. Results of bioassays indicated that the weeds dogfennel and mayweed chamomile are potentially allelopathic to alfalfa and Italian ryegrass seedlings. Leaf-tissue extracts from the two weed species reduced seedling growth more than stem and root extracts. In most experiments alfalfa seedlings were influenced more than Italian ryegrass seedlings and seedling growth was influenced more than seed germination. Leaf tissue from the weed species mixed into potting soil at a concentration as low as 0.25% (w/w) significantly reduced alfalfa and Italian ryegrass plant development and foliage production. Extract and tissue concentration used in this research were estimated to be similar to concentrations expected to occur within the pasture ecosystem and below concentrations that would result in hypertonicity in the bioassays.

The effect of an irradiance-dependent cavity mirror on the shape of a laser pulse is considered in the context of the CO2 laser, using an InSb etalon as the mirror, with special reference to the production of square pulses. A dynamical instability is found experimentally, in numerical solutions of a rate equation model, and in a simplified stability analysis. This instability leads to a transient ringing, or even a train of short pulses rather than the more desirable long square pulse, unless the response time of the nonlinear mirror is very short.

Small area chemically-milled parallel-grid avalanche counters (PGAC) with isobutane counter gas and thin entrance and exit windows, have been developed as transmission timing detectors for use in heavy-ion experiments. The performance of the counters has been investigated with α particles and elastically scattered 35Cl ions. To optimize the PGAC capabilities it is best to operate at pressures greater than 14 Torr where good timing and efficiency are available well below the breakdown threshold. A system timing resolution, using a silicon surface barrier stop detector, of 360 ps was achieved.

We report the operation and performance of a compact, high-efficiency 8Be detector designed for use in breakup reaction studies. It offers a number of advantages over previous detectors in allowing accurate kinematical identification of 8Be excited states and scattering angle as well as allowing large solid angle coverage.

In this paper, the authors demonstrated that microfluidic devices can be used to perform on-chip THz spectroscopy of biomolecules and chemical agents with high signal-to-noise ratios.

The Federal Aviation Administration (FAA) plans to replace current terrestrial navigation systems with a satellite-based system called the Global Navigation Satellite System (GNSS). The two main systems planned for navigation are the Wide Area Augmentation System (WAAS) and the Local Area Augmentation System (LAAS). Both systems rely on the Global Positioning System (GPS) satellite constellation, augmented by a combination of additional geostationary satellites and ground reference signals. These augmentations are required to meet aviation requirements for service availability, integrity, continuity, and accuracy. Together, WAAS and LAAS will provide seamless navigation coverage throughout the National Airspace System (NAS). WAAS will provide en route and terminal guidance throughout the NAS and Category I landing guidance at most airports. LAAS will be used exclusively to provide Category II and III landing guidance at all airports, and Category I where it is not provided by WAAS. This paper presents the approach and methodology used in developing a combined cost benefit analysis of both systems. Previous analyses addressed separate and independent implementations of each system. The combined analysis is designed to capture all costs and benefits attributable to both systems, ensuring a comprehensive and fair assessment. The analysis attributes costs and benefits to air carriers and other aircraft operators, passengers of air carriers, airport operators, and the FAA. Cost avoidance is included through the decommissioning of the current terrestrial navigation infrastructure.

The breakup of {sup 25}Mg has been studied using a beam of 180 MeV {sup 25}Mg with a {sup 12}C target. The main reaction channels investigated are the near-symmetric breakup into {sup 12}C+{sup 13}C and symmetric breakup into {sup 12}C+{sup 12}C following neutron transfer to the target. The symmetric breakup into two {sup 12}C nuclei is observed to occur from states at high excitation in {sup 24}Mg. The yield is, however, about two orders of magnitude smaller than that observed in a similar experiment using a {sup 24}Mg beam.

PBPK models are developed in the hope that they will improve our ability to extrapolate from one species to another and from one exposure regime to another. Evidence that a dose measure was successful at reconciling the available animal bioassay data would be encouraging. It would give us some confidence that the dose measure (as evaluated by a PBPK model) might yield reasonable predictions for yet other species (e.g., humans) and other dose routes. We have investigated the ability of a modified version of the Corley et al. (R. A. Corley, A. L. Mendrala, F. A. Smith, D. A. Staats, M. L. Gargas, R. B. Conolly, M. E. Andersen, and R. H. Reitz, 1990, Toxicol. Appl. Pharmacol. 103, 512-527) PBPK model for chloroform to reconcile the available bioassay data. Two rate-dependent dose measures, maximal rate of metabolism in the liver, and percentage of hepatocytes killed per day performed well at reconciling the rodent liver bioassay data, while all rate-independent dose measures performed less well. In contrast, none of the PBPK dose measures were capable of reconciling the rat and mouse kidney tumor response data. Here, administered dose scaled to body surface area performed the best.

A new approach to characterizing the state of knowledge about carcinogenic potency is described. In this approach, the carcinogenic risk posed by a specific dose is characterized by a probability distribution, indicating the relative likelihood of different risk estimates. The approach utilizes expert judgment and a probability tree and is illustrated in a case study of chloroform exposure. Experts in cancer biology/toxicology, pharmacokinetics, and dose-response modeling were identified by a panel of science-policy specialists. In a workshop, experts reviewed the chloroform data, received training in probability elicitation, and constructed a consensual probability tree based on biological theories of cancer causation. Distributions of carcinogenic risk were developed based on the probability tree, chloroform data, judgmental probabilities provided by the experts, and classical statistical techniques. Risk distributions varied considerably between experts, with some predicting essentially no risk from 100 ppb chloroform in drinking water while others have at least some probability on risks generally considered of regulatory significance. Estimated human risk was much lower when extrapolating from liver tumors in animals than from kidney tumors. Issues of scientific disagreement leading to different risk distributions between experts are discussed. The resulting risk distributions are compared to standard EPA risk calculations for the same exposure scenario as well as to the expert judgments of epidemiologists about cancer risks of chlorinated drinking water. Issues in combining expert judgments are discussed, and several alternative methods are presented. Strengths and weaknesses of the distributional approach are discussed.

Fourteen lactating and cycling Holsteins in each of two summers were assigned randomly to pens in a free-stall barn either with or without overhead fans to study the effect of fan cooling on certain endocrine and behavioral responses during the estrous cycle. After an adjustment period of 8 d in the first summer and 21 d in the second summer, jugular cannulas were inserted, and 25 mg of PGF2 alpha were injected. After injection, blood samples were collected frequently for 84 h in the first summer and 88 h in the second summer, followed by collection three times weekly for 3 wk thereafter each summer. Rectal temperatures were lower in the group cooled by fans than in the control group each summer. Luteal progesterone secretion tended to be greater in the fan group each summer; area under the luteal phase curve was significantly higher than for controls during the second summer. There was tendency for more preovulatory surges of LH and higher estrous responses rates in the fan group during the second summer. Thus, fan cooling of lactating dairy cows for several weeks before anticipated breeding provides potential for more efficient reproductive performance during the summer.

A semiconductor material which has been widely studied for its optical properties is Indium Antimonide. It shows a usable optical nonlinearity at room temperature in the 9-11 μm wavelength range of the CO2 laser which is of importance in many applications.

Mass, energy, charge and angular distributions from fully damped reactions of the 40 Ca + 40 Ca system have been measured at 197 and 231 MeV, in both singles and coincidence. The data display features of compound nucleus fission. Comparison with similar, but asymmetric systems, however, shows an entrance-channel dependence which invalidates a fusion-fission description. A discussion in terms of fission barriers calculated using the finite-range liquid drop model suggests a fast-fission mechanism. Re-analyses of systems studied in the literature are presented in terms of the finite-range liquid drop model, indicating fast fission — a process previously assumed only to be relevant for heavier systems — to be significant in most cases. Furthermore, using the finite-range liquid drop model, we find that the systematic behaviour of the mass distributions from systems where complete fusion-fission is expected to be dominant is well described in terms of the revised locus of the Businaro-Gallone transition from symmetric to asymmetric fission.

Kapton HN properties and the properties of the slip additive calcium phosphate dibasic (CaHPO{sub 4}) were investigated. Impurity analyses were performed on the compound by inductively coupled plasma (ICP) and ion chromatography (IC). Other analyses on the slip additive included: processing solution -- dissolution analysis, high-explosive compatibility studies, scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS), and particle size distribution. Testing and analyses were also performed on Kapton HN film and other polyimide films that could serve as possible replacements for Kapton HN. The polyimide films that were tested are: Upilex-R, Upilex-S, Upilex-SGA, and Apical. The analyses performed were: infrared (IR), x-ray photoelectron spectroscopy (XPS), SEM/EDS, high-potential breakdown testing, (PVD) physical vapor deposition adhesion tests, and peel tests. Upilex-S flyer cables were also fabricated and successfully test fired. In addition to these raw material tests, production cables were chemically treated and destructively (high potential) tested. A long-term aging environment for production cables was also selected, and aging tests were begun. 9 figs., 7 tabs.

Nonlinear optical parameters are found for intrinsic and n-doped indium antimonide by use of a hybrid cw–transversely excited atmosphere CO2 laser producing microsecond pulses. The Z-scan method is used, with both open and closed apertures. In addition, transverse ring profiles of defocused beams are analyzed. Results are obtained for 10.6- and 9.6-μm radiation and can be used to model the behavior of devices.

Interest in examining both the uncertainty and variability in environmental health risk assessments has led to increased use of methods for propagating uncertainty. While a variety of approaches have been described, the advent of both powerful personal computers and commercially available simulation software have led to increased use of Monte Carlo simulation. Although most analysts and regulators are encouraged by these developments, some are concerned that Monte Carlo analysis is being applied uncritically. The validity of any analysis is contingent on the validity of the inputs to the analysis. In the propagation of uncertainty or variability, it is essential that the statistical distribution of input variables are properly specified. Furthermore, any dependencies among the input variables must be considered in the analysis. In light of the potential difficulty in specifying dependencies among input variables, it is useful to consider whether there exist rules of thumb as to when correlations can be safely ignored (i.e., when little overall precision is gained by an additional effort to improve upon an estimation of correlation). We make use of well-known error propagation formulas to develop expressions intended to aid the analyst in situations wherein normally and lognormally distributed variables are linearly correlated.

The use of online Hypertexts, like "Les Chants de Maldoror" (Lautréamont), is a mean for literary research, of course, but also a mean for thinking and creating exercices for Learning of French as a second Language. Some examples in this paper may help to concieve the interest of these possibilities. The exercices we give as examples, with morpho-syntaxic or semantic purpose, are depending on the needs of the students and on their reactivity in the use of computers. Please Note : This paper contains some dynamic links, mainly to the Lautréamont hypertext.

The α-transfer reaction 12C(16O, 20Ne∗)8Be has been studied at a bombarding energy of 150 MeV in a search for high-spin α-cluster resonances in 20Ne. Angular correlations were measured for states in 20Ne which α-decay to the ground state of 16O. A broad 10+ resonance was located at E x ( 20 Ne )∼27.5 MeV , but no definite evidence was found for any 10+ strength at lower excitation energy.

Fundamental constructive theorems on the existence and uniqueness of the solution to the nonlinear Boltzmann transport equation for the isotropic field free case are utilised to set up a numerical solution process of controlled accuracy based on a functional iteration process arising directly from the theorems. It is demonstrated how a tabulation scheme describes the evolution of any reasonable initial distribution in velocity, space and time. Extensions are indicated for the particular problem of non-linear sputtering effects.