Comparison of haloacetic acids in the environment of the Northern and Southern Hemispheres.

Haloacetic acids (HAAs) are a family of compounds whose environmental concentrations have been extensively studied, primarily in Europe. Depending on the compound, their sources are believed to be both natural and anthropogenic. To better understand possible sources and contribute to the knowledge of the global distribution of these compounds, especially between the Northern and Southern Hemispheres, samples of precipitation, soils, and conifer needles were collected from Canada, Malawi, Chile, and the U.K. Precipitation samples exhibited highest HAA concentrations in collections from Canada, and lowest in those from Malawi. Malawi samples contained measurable levels of monobromoacetic acid (MBA) (56 ng/ L) unlike those from most other locations (< 9 ng/L). Soil HAA concentration levels were highest in the U.K. (e.g., 7.3 ng/g average TCA) and lowest in Malawi (0.8 ng/g average TCA), with Chile having higher levels (4.8 ng/g average TCA) than Canada (3 ng/g average TCA). Malawi soils contained small amounts of MBA (2 ng/g), in common with the two most southern of the 11 Chilean sites. Analysis of soil cores (10-cm depth sliced at 1 cm) from sites in Malawi and Chile showed that trichloroacetic acid (TCA) generally declined with depth while mono- and dichloroacetic acid (MCA and DCA) showed no trend. MCA, DCA, and TCA concentrations in archived U.K. soil samples increased by factors of 2, 4, and 5-fold over 75 years while TFA showed no consistent trend. Monochloroacetic acid (MCA) was detected in pine needles collected from Malawi. U.K. needle samples had the highest concentrations of all chloroacetic acids (CAAs): MCA, 2-18 ng/g; dichloroacetic acid (DCA), 2-38 ng/g; and trichloroacetic acid (TCA), 28-190 ng/g. Conifer needles from Canada and Chile contained CAAs at levels ranging from < 2 to 16 ng/g wet wt. Trifluoroacetic acid concentrations generally declined with increasing elevation in the samples from the Rocky Mountains in western Canada. The results indicate that concentrations of HAAs are greatest in the industrialized Northern Hemisphere but there are significant amounts of these compounds in the less industrialized Southern Hemisphere.

Trifluoroacetate profiles in the Arctic, Atlantic, and Pacific Oceans.

A series of depth profiles was collected at 22 sites in the Arctic, North and South Atlantic, and Pacific Oceans to determine spatial patterns for trifluoroacetate (TFA) concentrations in the marine environment and to investigate possible natural sources of TFA. Profiles were also taken over underwater vents in the North and South Pacific and the Mediterranean Sea. At the profile sites, TFA values ranged from <10 ng/L in the Pacific Ocean to greater than 150 ng/L in the Atlantic Ocean. Samples from the Canada Basin of the Arctic Ocean exhibited variable TFA concentrations (60-160 ng/L) down to 700 m. Below this depth, in water having 14C ages exceeding 1000 years, the TFA concentrations were constant (150 ng/L). Water returning to the Atlantic through the Canadian Arctic Archipelago had constant high TFA values. Profiles from the Northern Atlantic exhibited high values at all depths but were more consistent in the Western Atlantic. The northwestern Pacific Ocean surface profile sites exhibited low TFA concentrations in the top 100 m increasing to a maximum of 60 ng/L with depth. Samples from the South Pacific Ocean site had generally low values with a few depths (>800 m) having concentrations of 50 ng/L or more. To determine if underwater vents could contribute to the TFA concentrations in the oceans, profiles were taken over three vents in the Pacific and Mediterranean Oceans. The results suggest that some deep-sea vents may be natural sources of TFA.

Experimental systems implementation of a hybrid optical-digital correlator.

A high-speed hybrid optical-digital correlator system was designed, constructed, modeled, and demonstrated experimentally. This correlator is capable of operation at approximately 3000 correlations/s. The input scene is digitized at a resolution of 512 x 512 pixels and the phase information of the two-dimensional fast Fourier transform calculated and displayed in the correlator filter plane at normal video frame rates. High-fidelity reference template images are stored in a phase-conjugating optical memory placed at the nominal input plane of the correlator and reconstructed with a high-speed acousto-optic scanner; this allows for cross correlation of the entire reference data set with the input scene within one frame period. A high-speed CCD camera is used to capture the correlation-plane image, and rapid correlation-plane processing is achieved with a parallel processing architecture.

Compact phase-conjugating correlator: simulation and experimental analysis.

A simulation and experimental investigation of a recently proposed, compact, phase-conjugating correlator is undertaken. The effects of noise and other distortions in the input image and in the correlator filter plane are considered. As with other phase-only designs, the phase-conjugating correlator is sensitive to distortion of the input image while being robust in the presence of filter-plane distortions; this robustness is enhanced by the phase-conjugating property of the design.

High-speed, acousto-optically addressed optical memory.

A page-oriented, angle-multiplexed volume holographic optical-memory recording system has been constructed. This memory is addressed by the use of an acousto-optic deflector with a random-access time of 16 µs per page. This enables data transfer rates of 5.28 Gbits/s when pages of binary data are being stored. The reconstruction quality of images stored as memory pages is assessed with the quality achieved with the acousto-optic device compared with that achieved with the original recording optics.

The fate and impact of oil and oil-dispersant mixtures in freshwater pond ecosystems: introduction.

Oil and oil-dispersant mixtures were added to the surface waters of a series of man-made ponds. The fate of the oil and dispersant (Norman Wells crude and Corexit 9527 respectively) were studied as well as the impact of the added chemicals on the ponds' ecosystems. Elements of the ecosystems studied include bacteria, fungi, phytoplankton, periphyton , proto- and mesozooplankton , zoobenthos and surface insects. In addition a number of water quality parameters were regularly monitored. Comparisons were made between oil-treated and control ponds, as well as oil-dispersant treated and oil and/or control ponds. This paper describes the experimental set up and provides a summary of the findings reported in the following five papers.

The fate of oil and oil-dispersant mixtures in freshwater ponds.

The fate, distribution and composition of oil and oil-dispersant mixtures were studied in a series of five, lined, inground ponds containing sandy gravel sediment and mesotrophic water. Normal Wells crude oil and Corexit 9527 were added at nominal concentrations of 100 and 20 ppm, respectively, to two of the ponds, and the crude oil alone was added at 100 ppm to a third pond. The water surface, water column, the sediment, pond liner and attached biota were systemically sampled for a year. While only about 2% of the oil remained in the water column of the pond with no dispersant addition, in the pond with the dispersant, about 10% of the oil persisted in the water for several weeks. Most of the oil initially dispersed in the water returned to the water surface, then eventually sank to the sediment. Thinner surface films showed a higher dispersant content than the thicker slicks , and the thinner films had higher infrared carbonyl absorption. Final distribution calculations revealed that about 45% of the oil had degraded in the oil-dispersant-treated ponds during the one year study, while only 23% could not be accounted for in the oil pond. Changes in the oil composition during the experiment were similar in all ponds, with no evidence to suggest that the dispersant affected oil composition in any special manner.

Impact of oil and oil-dispersant mixtures on the fauna of freshwater ponds.

In a series of 5 artificial ponds, one was treated with a nomial concentration of 100 ppm of crude oil, two others were treated with a nominal 100 ppm of oil and 20 ppm of dispersant. Mesozooplankton populations were reduced in the oil-treated pond relative to the control pond, and eliminated in the oil-dispersant ponds. This condition persisted until the following year when the mesozooplankton was similar in all ponds. The protozooplankton experienced species shifts with Halteria and Strobilidium being eliminated initially in all treated ponds, but Halteria was collected in samples the following spring. Other protozoans such as thecamoebae increased in the treated ponds, while others, like zooflagellates , did not appear to be affected by the chemicals. Zoobenthos was affected by treatment, with the number of different types being reduced. The zoobenthos had recovered in one of the treated ponds the following spring, and that in the other treated ponds were recovering. Surface insects were eliminated after treatment, but recolonized during the next spring. Nekton were initially reduced by treatment. The population changes are discussed with respect to the fate of oil.

Impact of oil and oil-dispersant mixtures on flora and water chemistry parameters in freshwater ponds.

Oil and oil-dispersant mixtures at nominal concentrations of 100 and 20 ppm, respectively, were added to a series of ponds constructed for the study. In the pond treated with oil, there were no discernible short or long term effects on the phytoplankton. Both oil-dispersant treated ponds exhibited fluctuations in the dominant class of algae while the concentration of oil was greater than in the water column. Once the oil concentrations were below this value, there was no apparent effect. Periphytic material on the sides and bottoms of the oiled and control ponds were similar in mass and composed of a large number of species. Periphyton biomass was at least three times greater in both oil-dispersant-treated ponds with one genus dominating the growth. These conditions persisted in one of the oil-dispersant-treated ponds one year after treatment but those in the other pond had decreased to levels in the control pond at this time. Dissolved oxygen (DO) values decreased to about 4.6 ppm in both oil-dispersant-treated ponds shortly after treatment, but remained at approximately the saturation level in the other ponds for 6 weeks after treatment. Then these lower values gradually increased until they were slightly greater than in the controls. During the late winter months, both oil-dispersant ponds had anoxic zones above the sediment, the extent depending on the contours of the bottom. The DO values in the other ponds were at the saturation level. In the early spring, the nitrate ion-concentrations in control and oil-treated ponds were twice those measured for the oil-dispersant ponds. No discernible differences dependent on treatment were observed for nutrients or other ions monitored on a regular basis.

Comparison of morbidity in children requiring abdominal radiation and chemotherapy, with and without total parenteral nutrition.

We evaluated the effectiveness of total parenteral nutrition and placing the "bowel at rest," as compared to that of ad libitum food intake, on nutritional status and tolerance to combined chemotherapy and radiotherapy in a randomized, prospective trial in children with previously untreated malignancy requiring abdominal and pelvic irradiation and chemotherapy. Administration of TPN was found to be safe and efficacious in maintaining the children in good nutritional status during combined therapy; one-third of the control patients became malnourished and required TPN. There was no beneficial effect of "bowel at rest" and TPN on the ability of patients to tolerate combined therapies in terms of decreased toxicity; however, use of TPN was associated with improved adherence to chemotherapy schedules. Following termination of TPN or ad libitum food intake, and while receiving chemotherapy, the majority of the children who had previously received TPN lost significant weight. To date there has been no difference in mortality rate between the control and TPN groups. Although we conclude that TPN per se had little beneficial effect beyond that of maintaining good nutritional status, every child undergoing intensive combined therapy should have early and periodic assessments of nutritional status, so that the early signs of malnutrition can be detected, and the adverse effects of malnutrition can be prevented by nutritional replenishment, by TPN, or by other methods.

Multidisciplinary treatment of advanced stages of embryonal rhabdomyosarcoma in children.

Twenty-eight previously untreated patients with embryonal rhabdomyosarcoma, stages II to IV, were treated with the T-6 induction protocol and maintained on the T-2 protocol. The T-6 protocol consisted of simultaneous administration of drugs and irradiation, given in 3 parts each separated by an obligatory period of rest. Twenty-four of the 28 patients (85.7%) survived 4 to 44 months, with a median follow-up of 24 months; 18 (64%) have been in continuous disease-free status. The immediate toxicity of the T-6 induction was severe and required intensive supportive care. To date, the results from the T-6 induction protocol were more effective than those achieved with the T-2 protocol.

Multidisciplinary treatment of embryonal rhabdomyosarcoma in children: a progress report.

Fifty-nine patients under 21 years of age with embryonal rhabdomyosarcoma were treated according to a multidisciplinary protocol (T-2). The protocol consisted of surgical removal of the tumor, if possible, determination of clinicopathologic stages of the disease followed by radiotherapy for stages IB to IV, and chemotherapy. Radiation therapy was given in the range of 4,500--7,000 rad. The chemotherapy given for 2 years consisted of cycles of sequential administration of dactinomycin, adriamycin, vincristine, and cyclophosphamide. Forty-five of the patients (76%) are alive with no evidence of disease for 6 to 100 months (median follow-up of 57 ml). These include 19 of the 21 patients with stage IA (localized tumors, completely resected), 10 of the 10 stage IB (resected tumors, microscopic residual), 8 of the 9 stage II (unresectable tumors), 7 of the 14 stage III (unresectable tumors plus regional node involvement), and 1 of the 5 patients with stage IV (metastatic) disease. These results are superior to those achieved in 1960--70 at the Memorial Sloan-Kettering Cancer Center.