Contributions of organic and inorganic matter to sediment volume and accretion in tidal wetlands at steady state.

A mixing model derived from first principles describes the bulk density (BD) of intertidal wetland sediments as a function of loss on ignition (LOI). The model assumes that the bulk volume of sediment equates to the sum of self-packing volumes of organic and mineral components or BD = 1/[LOI/k + (1-LOI)/k], where k and k are the self-packing densities of the pure organic and inorganic components, respectively. The model explained 78% of the variability in total BD when fitted to 5075 measurements drawn from 33 wetlands distributed around the conterminous United States.

Bivalves as indicators of environmental variation and potential anthropogenic impacts in the southern Barents Sea.

Identifying patterns and drivers of natural variability in populations is necessary to gauge potential effects of climatic change and the expected increases in commercial activities in the Arctic on communities and ecosystems. We analyzed growth rates and shell geochemistry of the circumpolar Greenland smooth cockle, Serripes groenlandicus, from the southern Barents Sea over almost 70 years between 1882 and 1968. The datasets were calibrated via annually-deposited growth lines, and growth, stable isotope (delta(18)O, delta(13)C), and trace elemental (Mg, Sr, Ba, Mn) patterns were linked to environmental variations on weekly to decadal scales.

An innovative approach to student internships on American Indian reservations.

Personnel shortages are evident for a number of disciplines in the health professions, from physicians to nurses. Project CRISTAL (Collaborative Rural Interdisciplinary Service Training and Learning) was designed to immerse students in rural and reservation communities and encourage them to consider practicing in locations that have shortages of health care providers. Students gain an understanding of the importance of working as part of a health care team and address present and future health care workforce shortages.

Ecosystem collapse in Pleistocene Australia and a human role in megafaunal extinction.

Most of Australia's largest mammals became extinct 50,000 to 45,000 years ago, shortly after humans colonized the continent. Without exceptional climate change at that time, a human cause is inferred, but a mechanism remains elusive. A 140,000-year record of dietary delta(13)C documents a permanent reduction in food sources available to the Australian emu, beginning about the time of human colonization; a change replicated at three widely separated sites and in the marsupial wombat.

Stable isotope characteristics across narrow savanna/woodland ecotones in Wolfe Creek Meteorite Crater, Western Australia.

The stable isotopic composition (delta13C) of sediments from lakes are frequently analyzed to reconstruct the proportion of the regional vegetation that used either the C3 or C4 photosynthetic pathways, often without conducting a detailed survey of the current local vegetation. We performed a study on the modern vegetation composition within the Wolfe Creek Meteorite Crater to complement our future paleoecological investigation of the crater. A bull's-eye pattern exists where C4 grasses dominate an outer ring and salt tolerant species, including shrubs, herbs, chenopods, and halophytic algae, dominate the inner pan of the crater.

Prostate cancer patients' satisfaction with medical information.

A convenience sample of 965 Canadian men with prostate cancer were surveyed about their experience with, and opinions about, prostate cancer illness and treatment. Questionnaires were distributed by urologists, physicians at selected cancer treatment centers, and prostate cancer self-help groups. In this paper, we report on issues related to men's satisfaction with medical information.

Results of a survey of Canadian men with prostate cancer.

A cross-sectional survey was conducted with a convenience sample of 965 Canadian men with prostate cancer. Questionnaires were distributed to patients by individual urologists, physicians at cancer treatment centres, and prostate cancer self help groups. Most respondents were satisfied by the information received and the communication style of health professionals, although there was a substantive subsample of dissatisfied men.