Evaluation of Fast-Forward Video Visualization.

We evaluate and compare video visualization techniques based on fast-forward. A controlled laboratory user study (n = 24) was conducted to determine the trade-off between support of object identification and motion perception, two properties that have to be considered when choosing a particular fast-forward visualization. We compare four different visualizations: two representing the state-of-the-art and two new variants of visualization introduced in this paper. The two state-of-the-art methods we consider are frame-skipping and temporal blending of successive frames. Our object trail visualization leverages a combination of frame-skipping and temporal blending, whereas predictive trajectory visualization supports motion perception by augmenting the video frames with an arrow that indicates the future object trajectory. Our hypothesis was that each of the state-of-the-art methods satisfies just one of the goals: support of object identification or motion perception. Thus, they represent both ends of the visualization design. The key findings of the evaluation are that object trail visualization supports object identification, whereas predictive trajectory visualization is most useful for motion perception. However, frame-skipping surprisingly exhibits reasonable performance for both tasks. Furthermore, we evaluate the subjective performance of three different playback speed visualizations for adaptive fast-forward, a subdomain of video fast-forward.

ACE-Asia intercomparison of a thermal-optical method for the determination of particle-phase organic and elemental carbon.

A laboratory intercomparison of organic carbon (OC) and elemental carbon (EC) measurements of atmospheric particulate matter samples collected on quartz filters was conducted among eight participants of the ACE-Asia field experiment The intercomparison took place in two stages: the first round of the intercomparison was conducted when filter samples collected during the ACE-Asia experiment were being analyzed for OC and EC, and the second round was conducted after the ACE-Asia experiment and included selected samples from the ACE-Asia experiment Each participant operated ECOC analyzers from the same manufacturer and utilized the same analysis protocol for their measurements. The precision of OC measurements of quartz fiber filters was a function of the filter's carbon loading but was found to be in the range of 4-13% for OC loadings of 1.0-25 microg of C cm(-2). For measurements of EC, the precision was found to be in the range of 6-21% for EC loadings in the range of 0.7-8.4 microg of C cm(-2). It was demonstrated for three ambient samples, four source samples, and three complex mixtures of organic compounds that the relative amount of total evolved carbon allocated as OC and EC (i.e., the ECOC split) is sensitive to the temperature program used for analysis, and the magnitude of the sensitivity is dependent on the types of aerosol particles collected. The fraction of elemental carbon measured in wood smoke and an extract of organic compounds from a wood smoke sample were sensitive to the temperature program used for the ECOC analysis. The ECOC split for the three ambient samples and a coal fly ash sample showed moderate sensitivity to temperature program, while a carbon black sample and a sample of secondary organic aerosol were measured to have the same split of OC and EC with all temperature programs that were examined.

Organochlorine residues in marine mammals from the northern hemisphere--a consideration of the composition of organochlorine residues in the blubber of marine mammals.

Levels of organochlorines (PCBs, sigma DDT, lindane and its isomers, HCB, chlordane, and toxaphene) were determined in blubber of marine mammals from the northern hemisphere. Differences in both levels and ratios of organochlorine compounds were detected in different species of marine mammals living in the same region, e.g. blubber of harbour seals (Phoca vitulina) accumulated significantly lower levels of lindane, HCB, toxaphene, and DDT and its metabolites than harbour porpoises (Phocoena phocoena). Compared to such elementary differences in the organochlorine pattern in different marine mammals, the influence of age and sex on the results was only minimal. Varying ratios of contaminants in individual harbour porpoises were explained by migration. Constant PCB/DDT ratios were measured in harbour seals. Due to the sedentariness of harbour seals, even local sources of contaminants could be recognized. Careful evaluation of the organochlorine levels and ratios in marine mammals made it possible to monitor the transport of PCBs from the European continent to European Arctic regions.

Histological investigations on the thyroid glands of marine mammals (Phoca vitulina, Phocoena phocoena) and the possible implications of marine pollution.

In 1988 and 1989, thousands of harbor seals (Phoca vitulina) died in the North Sea from phocine distemper infection. The morphology of thyroid glands from 40 harbor seals found dead on the North Sea coastlines of Schleswig-Holstein, Federal Republic of Germany, during an epizootic of phocine distemper, was compared with the morphology of thyroid glands from five healthy harbor seals collected in Iceland. Thyroid glands from seven harbor porpoises (Phocoena phocoena) found dead in 1990 on the North Sea coastlines also were evaluated. Colloid depletion and fibrosis were found in the thyroid glands of harbor seals which died during the epizootic, but not in animals from Iceland. Thyroid glands of the porpoises showed similar lesions, but to a lesser degree, than those observed in the North Sea seals.

Histopathological findings in harbour seals (Phoca vitulina) found dead on the German North sea coast.

Various organs--lung, trachea, liver, kidney, heart, adrenal gland, skin, spleen, thymus, lymph node, gut, thyroid, spinal cord and brain--were removed from 43 seals at dissections performed on the German North sea coast. The specimens were fixed in formalin and routinely processed for light microscopy. The major pathological findings were Lung: acute congestion with interstitial and intra-alveolar oedema; intra-alveolar haemorrhage; suppurative bronchitis and bronchopneumonia; larvae and adult forms of Parafilaroides gymnurus. Liver: acute congestion; granulomatous lesions and infiltrates of eosinophils; intravascular nematodes. Spleen: varying degrees of atrophy of the white pulp; haemosiderosis; acute congestion of the red pulp. Lymph nodes: varying degrees of atrophy of the lymphatic tissue; long-standing sinus histiocytosis with partial fibrotic obliteration of the lumina; parasitic infiltration, sometimes with the Splendore-Hoeppli phenomenon; germinal centre hyperplasia. Thymus: pronounced atrophy of the lymphatic tissue, particularly in the cortical areas. Thyroid: marked reduction in colloid content. The other organs studied were normal or showed only minor histopathological changes. The morphological findings do not allow definite conclusions to be made about the aetiology and pathogenesis of the illness and death of the seals. However, evidence has been published that the seals' illness is probably due to canine distemper virus. The atrophy of the lymphoreticular tissues is consistent with infection by this virus.