Seven pairs of southern elephant seals (Mirounga leonina) pups and their dams were sampled during the late weaning season among a breeding population of seals on Elephant Island in Antarctica. The ...blubber of the pups and the milk and blubber of their dams were analyzed for lipid-normalized concentrations of PCBs and organochlorines compounds in order to evaluate the lactational transfer of these contaminants. The lipid-normalized concentrations in these tissues were in the ppb range (i.e., ngg−1 lipid). The levels of contaminants in southern elephant seals were low in comparison with residues that have been reported in pinnipeds from the northern hemisphere. The relative tissue concentrations of the analytes measured followed the pattern: ΣDDT>mirex>ΣPCB>Σchlordane>HCB>heptachlor epoxide>dieldrin>methoxychlor>ΣHCH>other organochlorines. The very high DDE/ΣDDT ratio (0.91) in the blubber of dams and pups was an indicative of long-term, extremely distant pollution. On the other hand, the relatively high levels of some other organochlorine pesticides (e.g. mirex, heptachlor epoxide, dieldrin, methoxychor) may reflect the continued use of these insecticides in developing countries located in the southern hemisphere. For most of the analytes measured, the lipid-normalized concentrations were lower in pup blubber and in the milk than in the maternal blubber. Lactational transfer rates were dependent on the logKow (octanol/water partition coefficient) values of the analytes measured, less lipophilic compounds being more readily transferred to the pups by the lactational route.
Presenting the fundamentals and practical applications of neural information systems, this volume presents the recent developments in the field. Self-organizing structures, neural grammar networks ...and model complexity are among the many topics discussed.
We have conducted a randomized trial which investigated the ability of dietary changes (in particular diets rich in cruciferous vegetables and flavonoids), to increase urinary antimutagenicity and ...inhibit DNA damage in smokers. Ninety heavy smokers were recruited and randomly assigned to three groups, and were given three different diets. The first diet was based on flavonoid-rich foods, particularly cruciferous vegetables, but not based on supplementation; the second was a normal isocaloric diet (with an adequate administration of fruits and vegetables); and the third was based on supplementation of flavonoids in the form of green tea and soy products. DNA adducts were measured by 32P-postlabelling in exfoliated bladder cells at different times since the start of the trial. In spite of randomization, subjects in the control group smoked more than those in the experimental groups, and this can explain the higher adduct levels at baseline. A slight decrease in bulky DNA adducts in exfoliated bladder cells was observed after 1 year since the end in the supplementation group and after 1 month in white blood cells. The only statistically significant association was found in a regression model that adjusted for smoking, in which the increase in flavonoid intake was associated with a decrease in adducts after 1 year (P = 0.02). These data suggest that adherence to a diet rich in cruciferous vegetables and flavonoids might reduce genotoxicity in the human urinary bladder of smokers, but they should be interpreted with caution owing to small numbers and the uneven distribution of smoking habits in the experimental groups. Smoking is the most important single preventable cause of cancer; at the present stage of knowledge it is totally unlikely that certain dietary habits can seriously counteract the effects of tobacco smoking.
We have undertaken a randomized trial to confirm the ability of a class of phenolics, flavonoids, to increase urinary anti-mutagenicity in smokers. Ninety heavy smokers were recruited and randomly ...assigned to three groups, who were given three different diets. One diet was rich in flavonoids, but not based on supplementation (‘flavonoid’), one was a normal iso-caloric diet with an adequate administration of fruit and vegetables (‘normal’), and one was based on supplementation of flavonoids in the form of green tea and soy products (‘supplement’). The urinary anti-mutagenicity—as inhibiting effect of the urinary extracts on the mutations induced by MeIQx—was measured in
Salmonella typhimurium YG1024 in the presence of liver S9 from male Sprague–Dawley rats treated with Aroclor 1254. The amount of total phenolics in the urinary extracts was measured by use of spectrometric analysis. We found that important dietary modifications can be achieved through special recipes and instructions given by a cook during an intensive course. The intervention was focused on increasing the flavonoid intake, and it was successful in that respect. In fact, differences in flavonoid intake were appreciated mainly between the first group (normal diet) and the other two (flavonoid-rich and supplemented diet), suggesting that dietary modification can be as effective as supplementation. However, both urinary anti-mutagenicity and the amounts of urinary phenolics did not change as a consequence of the trial. These results suggest that only a small fraction of urinary phenolics is influenced by dietary changes in the intake of flavonoids, and that most urinary anti-mutagens and phenolics are metabolites of dietary flavonoids, whose formation is more affected by the activity and diversity of bacterial flora in the colon than by the quantity and type of intake. A strong correlation was found between urinary phenolics and anti-mutagenicity in all the groups involved in the trial. Such correlation was not explained by dietary variables.
Localizing objects in images is a difficult task and represents the first step to the solution of the object recognition problem. This paper presents a novel approach to the localization problem ...based on recursive neural networks (RNNs), In particular, a recursive learning paradigm is proposed to process directed acyclic graphs with labeled edges, and to realize mappings between graphs which are isomorph, i.e. that share the same topology of the links. The RNN model, that assumes a graph-based representation of images, uses a state transition function that depends on the edge labels and is independent from both the number and the order of the children of each node. Moreover, the presence of targets attached to the internal nodes guarantees a fast learning, particularly sensitive to the local features of the graph. Some preliminary experiments, carried out on artificial images created using the COIL collection, are reported, showing very promising results
Recursive processing of cyclic graphs Bianchini, M.; Gori, M.; Sarti, L. ...
IEEE transactions on neural networks,
2006-Jan., 2006, 2006-Jan, 2006-01-00, 20060101, Letnik:
17, Številka:
1
Journal Article
Recursive neural networks are a powerful tool for processing structured data. According to the recursive learning paradigm, the input information consists of directed positional acyclic graphs ...(DPAGs). In fact, recursive networks are fed following the partial order defined by the links of the graph. Unfortunately, the hypothesis of processing DPAGs is sometimes too restrictive, being the nature of some real-world problems intrinsically cyclic. In this paper, a methodology is proposed, which allows us to process any cyclic directed graph. Therefore, the computational power of recursive networks is definitely established, also clarifying the underlying limitations of the model.
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