Abstract Over decades, persistent organic pollutants (POPs) and trace metals like mercury (Hg) have reached the remotest areas of world such as Antarctica by atmospheric transport. Once deposited in polar areas, low temperatures, limited solar radiation lead to long environmental residence times, allowing toxic substances accumulate biota. We investigated load polychlorinated biphenyls (PCBs) d...

These notes introduce a new kind of classifier called a dyadic decision tree (DDT). We also introduce a discrimination rule for learning a DDT that achieves the optimal rate of convergence, ER(ĥn) − R∗ = O(n−1/d), for the box-counting class, which was defined in the previous set of notes. This improves on the rate of ER(ĥn)−R = O(n−1/(d+2)) for the histogram sieve estimator from the previous no...

The mode of explosive burning in Type Ia SNe remains an outstanding problem. It is generally thought to begin as a subsonic deflagration, but this may transition into a supersonic detonation (the DDT). We argue that this transition leads to a breakout shock, which would provide the first unambiguous evidence that DDTs occur. Its main features are a hard X-ray flash (∼ 20 keV) lasting ∼ 10−2 s w...

Prenatal levels of organohalogen compounds (OHCs), including polybromodiphenyl ethers (PBDEs), polychlorobiphenyls (PCBs), hexachlorobenzene (HCB), hexachlorocyclohexanes and DDTs, have been investigated in two different cohorts from the Spanish Mediterranean area, Valencia and Menorca, by analysis of cord blood serum. Comparison of the observed median concentrations to other cohorts shows low ...

Brown pelicans (Pelecanus occidentalis) were listed as endangered in the United States in 1970, largely due to reproductive failure and mortality caused by organochlorine contaminants, such as DDT. The southeast population, P.o. carolinensis, was delisted in 1985, while the west coast population, P.o. californicus, was not delisted until 2009. As fish-eating coastal seabirds, brown pelicans may...

Classification of the relationship between electronic structures and biological activities of endocrine disruptors (so-called environmental hormones) was attempted using the parameters of absolute hardness (eta), absolute electronegativity (chi), and global softness (S), approximately defined as eta=1/2(epsilonLUMO-epsilonHOMO), chi=-1/2(epsilonHOMO+ epsilonLUMO), and S=1/eta, respectively, bas...

Concentrations of persistent organic pollutants including polychlorinated biphenyls (PCBs), organochlorine (OC) pesticides and dioxin-like compounds were measured in green-lipped mussels, Perna viridis, collected from seven mariculture zones in Hong Kong between September and October in 2002 in order to evaluate the status, spatial distribution and potential sources of pollution in these areas....

Plastic debris were collected from eight beaches around San Diego County, California. Debris collected include: pre-production pellets and post-consumer plastics including fragments, polystyrene (PS) foam, and rubber. A total of n = 2453 pieces were collected ranging from <5 mm to 50 mm in size. The plastic pieces were separated by type, location, and appearance and analyzed for polycyclic arom...