We studied age, growth, and maturity of the oceanic whitetip shark Carcharhinus longimanus in the North Pacific, and the reproduction in the North and South Pacific, captured with tuna longline from Nov. 1967 to Oct. 1995. Vertebral rings were examined from 111 males (precaudal length: 54-172 cm) and 114 females (precaudal length: 50-195 cm). Minimum and maximum numbers of translucent rings wer...

We show  that a projective maximal submodule of afinitely generated, regular, extending module is a directsummand. Hence, every finitely generated, regular, extendingmodule with projective maximal submodules is semisimple. As aconsequence, we observe that every regular, hereditary, extendingmodule is semisimple. This generalizes and simplifies a result of  Dung and   Smith. As another consequen...

Annual growth rings from short-leaf pine trees in the Great Smoky Mountains National Park show suppressed growth and increased iron content between 1863 and 1912, a period of smelting activity and large sulfur dioxide releases at Copperhill, Tennessee, 88 kilometers upwind. Similar growth suppression and increases of iron and other metals were found in rings formed in the past 20 to 25 years, a...

Growth rings were used to determine the root age of medicinal Paeonia lactiflora from four producing areas, and their corresponding paeoniflorin content were measured based on the identification of ages. Different P. lactiflora root samples of different ages were collected from the four major growing areas in China: Bozhou, Anhui Province; Pan'an, Zhejiang Province; Zhongjiang, Sichuan Province...

BACKGROUND The content of medicinal bioactive constituents in huangqi is affected by plant age. In this study, we devised a quick and convenient method for determining the age of huangqi, which was cultivated in Hunyuan County (Shanxi Province). METHODS 1, 2, 3, 4, 5, 8, 10 growth years huangqi had 38 samples, all samples were collected separately. The growth rings in these samples were obser...

Extremely decay-resistant wood and fire-resistant bark allow California's redwoods to accumulate millennia of annual growth rings that can be useful in biological research. Whereas tree rings of Sequoiadendron giganteum (SEGI) helped formalize the study of dendrochronology and the principle of crossdating, those of Sequoia sempervirens (SESE) have proven much more difficult to decipher, greatly...

Lianas (woody vines) have a critical role in ecosystem dynamics, especially the tropics. At present, there is an increasing need to develop reliable methods measure liana’s growth and age, given their suggested increase abundance following deforestation events climatic changes. Dendrochronological analyses offer powerful tools that provide temporal information for ecological studies at differen...