Large-scale synchrony of gap dynamics and the distribution of understory tree species in maple-beech forests

Large-scale synchronous variations in community dynamics are well documented for a vast array of organisms, but are considerably less understood for forest trees. Because of temporal variations in canopy gap dynamics, forest communities—even old-growth ones—are never at equilibrium at the stand scale. This paucity of equilibrium may also be true at the regional scale. Our objectives were to determine (1) if nonequilibrium dynamics caused by temporal variations in the formation of canopy gaps are regionally synchronized, and (2) if spatiotemporal variations in canopy gap formation aVect the relative abundance of tree species in the understory. We examined these questions by analyzing variations in the suppression and release history of Acer saccharum Marsh. and Fagus grandifolia Ehrh. from 481 growth series of understory saplings taken from 34 mature stands. We observed that (1) the proportion of stems in release as a function of time exhibited a U-shaped pattern over the last 35 years, with the lowest levels occurring during 1975–1985, and that (2) the response to this in terms of species composition was that A. saccharum became more abundant at sites that had the highest proportion of stems in release during 1975–1985. We concluded that the understory dynamics, typically thought of as a stand-scale process, may be regionally synchronized

Assessing human diet and movement in the Tongan maritime chiefdom using isotopic analyses.

The rise of stratified societies fundamentally influences the interactions between status, movement, and food. Using isotopic analyses, we assess differences in diet and mobility of individuals excavated from two burial mounds located at the `Atele burial site on Tongatapu, the main island of the Kingdom of Tonga (c. 500 - 150 BP). The first burial mound (To-At-1) was classified by some archaeologists as a commoner's mound while the second burial mound (To-At-2) was possibly used for interment of the chiefly class. In this study, stable isotope analyses of diet (δ13C, δ15N, and δ34S; n = 41) are used to asses paleodiet and 87Sr/86Sr ratios (n = 30) are analyzed to investigate individual mobility to test whether sex and social status affected these aspects of life. Our results show significant differences in diet between burial mounds and sexes. Those interred in To-At-2 displayed lower δ13C values, indicating they ate relatively more terrestrial plants (likely starchy vegetable staples) compared with To-At-1 individuals. Females displayed significantly lower δ15N values compared with males within the entire assemblage. No differences in δ34S values were observed between sexes or burial mound but it is possible that sea spray or volcanism may have affected these values. One individual displayed the strontium isotopic composition representative of a nonlocal immigrant (outside 2SD of the mean). This suggests the hegemonic control over interisland travel, may have prevented long-term access to the island by non-Tongans exemplifying the political and spiritual importance of the island of Tongatapu in the maritime chiefdom

Living Kidney Donors Who Develop Kidney Failure: Excerpts of Their Thoughts

BackgroundPsychosocial data about living kidney donors have been collected for almost 5 decades now. To date, however, no study has provided any psychosocial follow-up of donors who developed a serious health problem such as end-stage renal disease (ESRD).MethodsDonors who developed ESRD were invited to participate in a qualitative interview if they met one or both of the inclusion criteria: (1) developed ESRD within 10 years of donating and/or (2) lacked health insurance at the time of donation. We contacted 38 individuals who met these criteria, and 22 participated (58%). Two were subsequently excluded from analysis.ResultsTwenty qualitative interviews were analyzed. Five findings are described: (1) donors describe the decision-making process as spontaneous and fast; (2) donors describe lack of appreciation for the need for post-donation self-care; (3) donors do not regret donating despite the adverse outcome; (4) donors advise future donors to have in place emotional and physical support post donation; and (5) donors appreciate the opportunity to tell their story from being a living donor to living with ESRD, which virtually all perceive as 2 separate unrelated events.ConclusionsMost donors are positive about their donation decision and experience and would donate again, despite developing ESRD themselves. They propose some important changes to the decision-making and informed-consent processes. Our data are reassuring regarding lack of donor regret, but highlight the need for living donor transplant programs to ensure that living donors understand their long-term risks and receive appropriate life-long follow-up care to minimize these risks

Sensory neurones recognise defined pathways in Drosophila central nervous system

SCOPUS: NotDefined.jinfo:eu-repo/semantics/publishe