Source-wavelet estimation during full-waveform inversion of ground-penetrating radar data

A major issue in the application of waveform inversion methods to crosshole ground-penetrating radar (GPR) data is the accurate estimation of the source wavelet. Here, we explore the viability and robustness of incorporating this step into a recently published time-domain inversion procedure through an iterative deconvolution approach. Our results indicate that, at least in non-dispersive electrical environments, such an approach provides remarkably accurate and robust estimates of the source wavelet even in the presence of strong heterogeneity of both the dielectric permittivity and electrical conductivity. Our results also indicate that the proposed source wavelet estimation approach is relatively insensitive to ambient noise and to the phase characteristics of the starting wavelet. Finally, there appears to be little to no trade-off between the wavelet estimation and the tomographic imaging procedures.

Evaluation of Asphalt Mix Permeability, MLR-90-2, 1992

Efforts to eliminate rutting on the Interstate system have resulted in 3/4 in. aggregate mixes, with 75 blow Marshall, 85% crushed aggregate mix designs. On a few of these projects paved in 1988-1989, water has appeared on the surfaces. Some conclusions have been reached by visual on-sight investigations that the water is coming from surface water, rain and melting snow gaining entry into the surface asphalt mixture, then coming back out in selected areas. Cores were taken from several Interstate projects and tested for permeability to investigate the surface water theory that supposedly happens with only the 3/4 in. mixtures. All cores were of asphalt overlays over portland cement concrete, except for the Clarke County project which is full depth AC. The testing consisted of densities, permeabilities, voids by high pressure airmeter (HPAM), extraction, gradations, AC content, and film thicknesses. Resilient modulus, indirect tensile and retained strengths after freeze/thaw were also done. All of the test results are about as expected. Permeabilities, the main reason for testing, ranged from 0.00 to 2.67 ft per day and averages less than 1/2 ft per day if the following two tests are disregarded. One test on each binder course came out to 15.24 ft/day, and a surface course at 13.78 ft/day but these are not out of supposedly problem projects.

Interactive readings of children's literature in day care: Microgenetic analysis of the semiopictorial construction.

In line with educational issues involved in emergent literacy practices in preschool, in particular those concerning comprehension processes, this paper focuses on picture-based narrative comprehension during an interactive reading session of a wordless picture book, involving a group of children aged three and their teacher. Children are asked to make inferences about the meaning and outcome of the story, a procedure which gradually elicits their responses on how events link together, thus enhancing their capacity to use prior and implicit knowledge to build the story meaning. Moreover, this study highlights the importance of interaction for developing comprehension. Data collected was analysed following didactic microgenesis, an analytical approach showing that knowledge built during interaction depends on the joint construction of a zone of common meaning by which teacher and children try to adjust to each other. In order to help the process of merging different meanings of the story built online, a text written by researchers, following the narrative structure of the story, was read by the teacher after the picture-based reading. This led us to examine through interactional analysis which semiotic cues were used during recall on the following day, as an additional measure of knowledge construction.

Solar Powered Highway Delineator System, HR-367, 1993

Currently, many drivers experience some difficulty in viewing the road ahead of them during times of reduced visibility, such as rain, snow, fog, or the darkness of night- Recent studies done by the National Safety Council provide a detailed contrast between fatal accidents occurring during the day and night. Revealed was that the motor vehicle night death rate (4.41 deaths per 100 million miles driven) was sharply higher than the corresponding death rate during daylight hours (1.21). By providing a delineating system powered by the natural resource of solar power, a constant source of visibility may be maintained throughout the evening. Along with providing enough light to trace the outline of the road, other major goals defined in producing this delineator system are as follows: 1. A strong and durable design that would protect the internal components and survive extreme weather conditions. 2. A low maintenance system where components need few repairs or replacements. 3. A design which makes all components accessible in the event that maintenance is needed, but also prevents vandalism. 4. A design that provides greater visibility to drivers and will not harm a vehicle or its passengers in the event of a collision. This solar powered highway delineator consists of an adjustable solar array, a light fixture, and a standard delineator pole. The solar array houses and protects the solar panels, and can be easily adjusted to obtain a maximum amount of sunlight. The light fixture primarily houses the battery, the circuit and the light assembly. Both components allow for easy accessibility and reduce vandalism using internal connections for bolts and wires. The delineator mounting pole is designed to extensively deform in the event of a collision, therefore reducing any harm caused to the vehicle and/or the passengers. The cost of a single prototype to be produced is approximately $70.00 excluding labor costs. However, these material and labor costs will be greatly reduced if a large number of delineators are produced. It is recommended that the Iowa Department of Transportation take full advantage of the research and development put into this delineator design. The principles used in creating this delineator can be used to provide an outline for drivers to follow, or on a larger scale, provide actual roadway lighting in areas where it was never before possible or economically feasible. In either event, the number of fatal accidents will be decreased due to the improved driver visibility in the evening.

Mediastinal reinforcement after induction therapy and pneumonectomy: comparison of intercostal muscle versus diaphragm flaps.

OBJECTIVE: Prospective non-randomised comparison of full-thickness pedicled diaphragm flap with intercostal muscle flap in terms of morbidity and efficiency for bronchial stump coverage after induction therapy followed by pneumonectomy for non-small cell lung cancer (NSCLC). METHODS: Between 1996 and 1998, a consecutive series of 26 patients underwent pneumonectomy following induction therapy. Half of the patients underwent mediastinal reinforcement by use of a pedicled intercostal muscle flap (IF) and half of the patients by use of a pedicled full-thickness diaphragm muscle flap (DF). Patients in both groups were matched according to age, gender, side of pneumonectomy and stage of NSCLC. Postoperative morbidity and mortality were recorded. Six months follow-up including physical examination and pulmonary function testing was performed to examine the incidence of bronchial stump fistulae, gastro-esophageal disorders or chest wall complaints. RESULTS: There was no 30-day mortality in both groups. Complications were observed in one of 13 patients after IF and five of 13 after DF including pneumonia in two (one IF and one DF), visceral herniations in three (DF) and bronchopleural fistula in one patient (DF). There were no symptoms of gastro-esophageal reflux disease (GERD). Postoperative pulmonary function testing revealed no significant differences between the two groups. CONCLUSIONS: Pedicled intercostal and diaphragmatic muscle flaps are both valuable and effective tools for prophylactic mediastinal reinforcement following induction therapy and pneumonectomy. In our series of patients, IF seemed to be associated with a smaller operation-related morbidity than DF, although the difference was not significant. Pedicled full-thickness diaphragmatic flaps may be indicated after induction therapy and extended pneumonectomy with pericardial resection in order to cover the stump and close the pericardial defect since they do not adversely influence pulmonary function.

Implementation of enhanced recovery after surgery (ERAS) in colorectal surgery is highly cost-effective

Objective: Enhanced Recovery After Surgery (ERAS) clinical pathways in¦colorectal surgery are known to reduce postoperative complications leading¦to shortened hospital stay. However, the implementation of such an ERAS¦pathway requires time and financial investment. This study evaluates whether¦the savings related to the reduction in the length of stay (LOS) outweigh the¦costs of implementing an ERAS pathway.¦Methods: An ERAS pathway was implemented in our institution for colorectal¦surgery. The first 50 consecutive patients subjected to this ERAS pathway¦(ERAS group) were compared to 50 consecutive patients that were operated one¦year before its introduction (control group). Primary LOS, readmission within¦30 days, and total costs based on costs per day were compared. The mean costs¦per day were: 3,263 CHF for intensive care, 1,152 CHF for intermediate care,¦and 728 CHF for basic care.¦Results: Primary LOS was shorter in the ERAS group than in the control¦group: median 7 (interquartile range 5-12·25) versus 10 (7-18) days (P =¦0·0025). The readmission within 30 postoperative days was similar in both¦groups (2 patients each). In the ERAS group, the added primary LOS was¦485 days (379 in basic care, 99 in intermediate care, 7 in intensive care) compared¦to 706 days in the control group (533 in basic care, 146 in intermediate care,¦27 in intensive care). The total costs were significantly lower for the 50 ERAS¦patients compared to the control group: 412,801 CHF versus 644,317 CHF (P <¦0·01). Investments required for the 50 first ERAS patients were approximately¦83,544 CHF, including 348 working hours as well a full-time ERAS dedicated¦nurse. The overall cost saving was approximately 2,959 CHF per patient.¦Conclusion: Implementation of an ERAS pathway significantly reduced LOS¦after colorectal surgery. The financial investment to introduce and maintain¦such a pathway is clearly inferior to the cost-saving of reduced hospital stay.

Full-waveform inversion of cross-hole ground-penetrating radar data to characterize a gravel aquifer close to the Thur River, Switzerland

Cross-hole radar tomography is a useful tool for mapping shallow subsurface electrical properties viz. dielectric permittivity and electrical conductivity. Common practice is to invert cross-hole radar data with ray-based tomographic algorithms using first arrival traveltimes and first cycle amplitudes. However, the resolution of conventional standard ray-based inversion schemes for cross-hole ground-penetrating radar (GPR) is limited because only a fraction of the information contained in the radar data is used. The resolution can be improved significantly by using a full-waveform inversion that considers the entire waveform, or significant parts thereof. A recently developed 2D time-domain vectorial full-waveform crosshole radar inversion code has been modified in the present study by allowing optimized acquisition setups that reduce the acquisition time and computational costs significantly. This is achieved by minimizing the number of transmitter points and maximizing the number of receiver positions. The improved algorithm was employed to invert cross-hole GPR data acquired within a gravel aquifer (4-10 m depth) in the Thur valley, Switzerland. The simulated traces of the final model obtained by the full-waveform inversion fit the observed traces very well in the lower part of the section and reasonably well in the upper part of the section. Compared to the ray-based inversion, the results from the full-waveform inversion show significantly higher resolution images. At either side, 2.5 m distance away from the cross-hole plane, borehole logs were acquired. There is a good correspondence between the conductivity tomograms and the natural gamma logs at the boundary of the gravel layer and the underlying lacustrine clay deposits. Using existing petrophysical models, the inversion results and neutron-neutron logs are converted to porosity. Without any additional calibration, the values obtained for the converted neutron-neutron logs and permittivity results are very close and similar vertical variations can be observed. The full-waveform inversion provides in both cases additional information about the subsurface. Due to the presence of the water table and associated refracted/reflected waves, the upper traces are not well fitted and the upper 2 m in the permittivity and conductivity tomograms are not reliably reconstructed because the unsaturated zone is not incorporated into the inversion domain.

Acid inhibition on the first day of dosing : comparison of four proton pump inhibitors

RESUME Introduction: Les inhibiteurs de la pompe à protons sont actuellement considérés comme les médicaments de choix pour le traitement des affections peptiques comme l'ulcère gastroduodénal et l'oesophagite de reflux. La rapidité, ainsi que le degré d'inhibition de la sécrétion gastrique acide sont importants pour le contrôle optimal des symptômes ainsi que pour le traitement de ces affections. But : Le but principal de cette étude a été de comparer, chez les sujets asymptomatiques non infectés par H. pylori, par pH-métrie intragastrique de 24 heures, la rapidité et la durée de l'action antisécrétoire de doses uniques de rabéprazole 20 mg, d'oméprazole capsule 20 mg, d'oméprazole en comprimé MUPS (« Multiple Unit Pellet System ») 20 mg, de pantoprazole 40 mg et de lansoprazole 30 mg, respectivement. Matériel et méthodes : Cette étude, effectuée en double aveugle et randomisée, a été conduite de manière croisée chez 18 sujets H. pylori-négatifs. Une pH-métrie de 24 heures a été effectuée le jour de l'administration du médicament (dose unique de rabéprazole 20 mg, de lansoprazole 30mg, de pantoprazole 40 mg, d'oméprazole capsule 20 mg, d'oméprazole MUPS comprimé 20mg, ou de placebo). Résultats : Le pH intragastrique médian (3.4 vs. 2.9, 2.2, 1.9 et 1.8, respectivement; p≤ 0.03) et le temps avec un pH supérieur à 4 pendant les 24 heures suivant la prise du médicament (8.0 heures vs. 7.4, 4.9, 2.9, et 3.0, respectivement; p≤ 0.003) ont été statistiquement plus élevés avec le rabéprazole qu'avec le lansoprazole, le pantoprazole, l'oméprazole capsule, l'oméprazole comprimé MUPS, ou le placebo. Les valeurs du pH pendant les périodes diurnes et nocturnes étaient plus hautes avec le rabeprazole et le lansoprazole qu'avec le pantoprazole, l'oméprazole capsule, et l'oméprazole comprimé MUPS (p≤0.04). Conclusion : Le rabéprazole s'est montré le plus efficace de tous les inhibiteurs de pompe à protons étudiés durant le premier jour de l'administration du médicament. SUMMARY Background: Rapid and consistent acid suppression on the first day of dosing may be important in treating acid-related disorders. Aim: To compare the antisecretory activity and onset of action of single doses of rabeprazole, lansoprazole, pantoprazole, omeprazole capsule, omeprazole multiple unit pellet system (MUPS) tablet and placebo in healthy Helicobacter pylori-negative subjects. Methods: This cross-over, double-blind, randomized study was performed in 18 H. pylori-negative subjects. Twenty-four-hour intragastric pH monitoring was performed on the day of treatment (once-daily dose of rabeprazole 20 mg, lansoprazole 30 mg, pantoprazole 40 mg, omeprazole capsule 20 mg, omeprazole MUPS tablet 20 mg or placebo). Results: The intragastric pH (3.4) and time at pH > 4 during the 24 h post-dose (8.0 h) were significantly greater with rabeprazole than with lansoprazole, pantoprazole, omeprazole capsule, omeprazole MUPS tablet or placebo (P ≤ 0.04 for rabeprazole vs. the others). Daytime and night-time pH values were higher with rabeprazole and lansoprazole than with pantoprazole, omeprazole capsule and omeprazole MUPS tablet (P ≤ 0.04). Conclusion: Rabeprazole was the most potent acid inhibitor of all the proton pump inhibitors tested during the first day of dosing.

Mental imagery for full and upper human bodies: common right hemisphere activations and distinct extrastriate activations.

The processing of human bodies is important in social life and for the recognition of another person's actions, moods, and intentions. Recent neuroimaging studies on mental imagery of human body parts suggest that the left hemisphere is dominant in body processing. However, studies on mental imagery of full human bodies reported stronger right hemisphere or bilateral activations. Here, we measured functional magnetic resonance imaging during mental imagery of bilateral partial (upper) and full bodies. Results show that, independently of whether a full or upper body is processed, the right hemisphere (temporo-parietal cortex, anterior parietal cortex, premotor cortex, bilateral superior parietal cortex) is mainly involved in mental imagery of full or partial human bodies. However, distinct activations were found in extrastriate cortex for partial bodies (right fusiform face area) and full bodies (left extrastriate body area). We propose that a common brain network, mainly on the right side, is involved in the mental imagery of human bodies, while two distinct brain areas in extrastriate cortex code for mental imagery of full and upper bodies.

Fast Track Portland Cement Concrete Pavement, HR-538, 1997

In 1987, 1.5 km (0.935 mi.) of Spruce Hill Drive in Bettendorf, Iowa was reconstructed. It is an arteriel street with commercial usage on both termini with single family residential dwellings along most of the project. A portland cement concrete (PCC) pavement design was selected, but a 14 day curing period would have been an undue hardship on the residents and commercial businesses. An Iowa DOT Class F fast track concrete was used so the roadway could be used in 7 to 10 days. The Class F concrete with fly ash was relatively sticky and exhibited early stiffening problems and substantial difficulty in obtaining the target entrained air content of 6.5%. These problems were never completely resolved on the project. Annual visual field reviews were conducted through 1996. In November 1991, severe premature distress was identified on the westbound two lanes of the full width replacement. The most deteriorated section in a sag vertical, 152 m (500 ft.) of the westbound roadway, was replaced in 1996. Premature distress has been identified on a dozen other conventional PCC Iowa pavements constructed between 1983 and 1989, so the deterioration may not be related to the fact that it was fast track pavement.

Value of positron emission tomography in full-thickness chest wall resections for malignancies.

Preoperative imaging for resection of chest wall malignancies is generally performed by computed tomography (CT). We evaluated the role of (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in planning full-thickness chest wall resections for malignancies. We retrospectively included 18 consecutive patients operated from 2004 to 2006 at our institution. Tumor extent was measured by CT and PET, using the two largest perpendicular tumor extensions in the chest wall plane to compute the tumor surface assuming an elliptical shape. Imaging measurements were compared to histopathology assessment of tumor borders. CT assessment consistently overestimated the tumor size as compared to PET (+64% vs. +1%, P<0.001). Moreover, PET was significantly better than CT at defining the size of lesions >24 cm(2) corresponding to a mean diameter >5.5 cm or an ellipse of >4 cm x 7.6 cm (positive predictive value 80% vs. 44% and specificity 93% vs. 64%, respectively). Metabolic PET imaging was superior to CT for defining the extent of chest wall tumors, particularly for tumors with a diameter >5.5 cm. PET can complement CT in planning full-thickness chest wall resection for malignancies, but its true value remains to be determined in larger, prospective studies.

Feasibility Study of Dynamic Overload and Ultimate Load Tests of Full-Scale Highway Bridges, HR-160, 1973

As a result of the construction of the Saylorville Dam and Reservoir on the Des Moines River, six highway bridges are scheduled for removal. Five of these are old high-truss single-lane bridges, each bridge having several simple spans. The other bridge is a fairly modern (1955) double 4-span continuous beam-and-slab composite highway bridge. The availability of these bridges affords an unusual opportunity for study of the behavior of full-scale bridges. Because of the magnitude of the potential testing program, a feasibility study was initiated and the results are presented in this two-part final report. Part I summarizes the findings and Part II presents the supporting detailed information.

Ultimate Load Behavior of Full-Scale Highway Truss Bridges, Summary Report, HR-169, 1975

As a result of the construction of the Saylorville Dam and Reservoir on the Des Moines River, six highway bridges crossing the river were scheduled for removal. One of these, an old pin-connected, high-truss, single-lane bridge, was selected for a comprehensive testing program which included ultimate load tests, service load tests, and a supplementary test program. A second bridge was used for a limited service load test program. The results of the research are detailed in two interim reports. The first interim report outlines the ultimate load tests and the second interim report details the results of the service load and supplementary test program. This report presents a summary of these findings along with recommendations for implementation of the findings.

Parents living with HIV in a high-income country: do patients need specific support?

The number of HIV-infected persons with children and caregiving duties is likely to increase. From this statement, the present study was designed to establish how HIV infected caregivers organise their parenting routines and to determine their support needs. A further aim was to ascertain caregivers' perception of conspicuous behaviours displayed by their children. Finally, it sought to determine the extent to which the caregivers' assessment of their parenting activity is influenced by the required support and their children's perceived conspicuous behaviours. The study design was observational and cross-sectional. Sampling was based on the 7 HIV Outpatient Clinics associated with the national population-based Swiss HIV Cohort Study. It focused on persons living with HIV who are responsible for raising children below the age of 18. A total of 520 caregivers were approached and 261 participated. An anonymous, standardised, self-administered questionnaire was used for data collection. The data were analysed using descriptive statistical procedures and backward elimination multiple regression analysis. The 261 respondents cared for 406 children and adolescents under 18 years of age; the median age was 10 years. The caregivers' material resources were low. 70% had a net family income in a range below the median of Swiss net family income and 30% were dependent on welfare assistance. 73% were undergoing treatment with 86% reporting no physical impairments. The proportion of single caregivers was 34%. 92% of the children were living with their HIV infected caregivers. 80% of the children attended an institution such as a school or kindergarten during the day. 89% of the caregivers had access to social networks providing support. Nevertheless, caregivers required additional support in performing their parenting duties and indicated a need for assistance on the material level, in connection with legal problems and with participation in the labour market. 46% of the caregivers had observed one or more conspicuous behaviours displayed by their children, which indicates a challenging situation. However, most of these caregivers assessed their parenting activity very favourably. Backward elimination multiple regression analysis indicated that a smaller number of support needs, younger age of the eldest child and fewer physical impairments on the part of the caregiver enhance the caregivers' assessment of their parenting activity. Physicians should speak to caregivers living with HIV about their parenting responsibilities and provide the necessary scope for this subject in their consultation sessions. Physicians are in a position to draw their patients' attention to the services available to them.