Growth, in terms of length, weight, and number of branches and/or dichotomies, in transplanted specimens of Ascophyllum nodosum ecad scorpioides in a temperate salt marsh is described. The ecad scorpioides, when transplanted from its characteristic habitat on the mid-intertidal, Spartina alterniflora-dominated, marsh flats to a location near mean low-water developed characteristics normally associated with A. nodosum ecad mackaii. The growth of these plants was more rapid than those in the mid-intertidal region and was not affected by the shading of algal fronds by S. alterniflora. Unusually high temperatures and light intensities during the winter and spring months were major factors affecting growth in plants that were subjected to relatively long periods of tidal exposure. The presence of S. alterniflora during the summer months may act in a protective capacity for mid-intertidal ecad populations.This research was supported by research grants AG-375 and BO 38018 from the National Science Foundation and, in part, by the State University of New York Research Foundation and the Energy Research and Development Administration (ERDA). 相似文献
In humans (Homo sapiens), sexual dimorphism in face shape has been proposed to be linked to quality in both men and women. Although preferences for
high-quality mates might be expected, previous work has suggested that high quality may be associated with decreased investment
in partnerships. In line with a trade-off between partner quality and investment, human females have been found to prefer
higher levels of masculinity when judging under conditions where the benefits of quality would be maximised and the costs
of low investment would be minimised. In this study, we examined facultative preferences for masculinity/femininity under
hypothetical high and low environmental harshness in terms of resource availability in which participants were asked to imagine
themselves in harsh/safe environments. We demonstrate that environmental harshness influences preferences for sexual dimorphism
differently according to whether the relationship is likely to be short or long term. Women prefer less-masculine male faces
and men prefer less-feminine female faces for long-term than short-term relationships under conditions of environmental harshness.
Such findings are consistent with the idea that high-quality partners may be low investors and suggest that under harsh ecological
conditions, both men and women favour a low-quality/high-investment partner for long-term relationships. For short-term relationships,
where investment is not an important variable, preferences for sexual dimorphism were similar for the low and high environmental
harshness conditions. These results provide experimental evidence that human preferences may be contingent on the environment
an individual finds itself inhabiting. 相似文献
Specimens of oceanic decapods, mysids and euphausiids, collected from the North East Atlantic Ocean during July 1985, were analysed for V, Cr, Mn, Fe, Ni, Co, Cu, Zn, As and Cd. Measurement of the metals was carried out using two techniques: inductively-coupled plasma-source mass spectrometry (ICP-MS) and atomic absorption (AAS). With the exception of the iron data, good agreement was observed between the data from the two techniques. Baseline-metal data are presented for the species measured, along with any effects of animal size on metal concentration. The data presented for oceanic animals from different trophic levels are important in studies of metal fluxes and for the assessment of markers within the food web in the oceans. 相似文献
We report a female infant noted prenatally to have an umbilical cord mass. At birth, a labial strawberry haemangioma was noted. She subsequently developed an abdominal mass which was discovered to be a proliferating haemangioma, continuous with both the labial and the umbilical stump lesions. 相似文献
Representing hydrologic connectivity of non‐floodplain wetlands (NFWs) to downstream waters in process‐based models is an emerging challenge relevant to many research, regulatory, and management activities. We review four case studies that utilize process‐based models developed to simulate NFW hydrology. Models range from a simple, lumped parameter model to a highly complex, fully distributed model. Across case studies, we highlight appropriate application of each model, emphasizing spatial scale, computational demands, process representation, and model limitations. We end with a synthesis of recommended “best modeling practices” to guide model application. These recommendations include: (1) clearly articulate modeling objectives, and revisit and adjust those objectives regularly; (2) develop a conceptualization of NFW connectivity using qualitative observations, empirical data, and process‐based modeling; (3) select a model to represent NFW connectivity by balancing both modeling objectives and available resources; (4) use innovative techniques and data sources to validate and calibrate NFW connectivity simulations; and (5) clearly articulate the limits of the resulting NFW connectivity representation. Our review and synthesis of these case studies highlights modeling approaches that incorporate NFW connectivity, demonstrates tradeoffs in model selection, and ultimately provides actionable guidance for future model application and development. 相似文献
Aim: The aim of this study was to synthesize published qualitative studies to identify older adults' preferences for communication about driving with health care providers.
Background: Health care providers play a key role in addressing driving safety and driving retirement with older adults, but conversations about driving can be difficult. Guides exist for family members and providers, but to date less is known about the types of communication and messages older drivers want from their health care providers.
Design: A qualitative metasynthesis of studies published on or before October 10, 2014, in databases (PubMed, CINAHL, PsycINFO, and Web of Science) and grey literature was performed.
Review Methods: Twenty-two published studies representing 518 older adult drivers met the following inclusion criteria: the study (1) was about driving; (2) involved older drivers; (3) was qualitative (rather than quantitative or mixed methods); and (4) contained information on older drivers' perspectives about communication with health care providers.
Results: We identified 5 major themes regarding older adults' communication preferences: (1) driving discussions are emotionally charged; (2) context matters; (3) providers are trusted and viewed as authority figures; (4) communication should occur over a period of time rather than suddenly; and (5) older adults desire agency in the decision to stop driving.
Conclusion: Various stakeholders involved in older driver safety should consider older drivers' perspectives regarding discussions about driving. Health care providers can respect and empower older drivers—and support their family members—through tactful communication about driving safety and mobility transitions during the life course. 相似文献
Establishing protected areas, where human activities and land cover changes are restricted, is among the most widely used strategies for biodiversity conservation. This practice is based on the assumption that protected areas buffer species from processes that drive extinction. However, protected areas can maintain biodiversity in the face of climate change and subsequent shifts in distributions have been questioned. We evaluated the degree to which protected areas influenced colonization and extinction patterns of 97 avian species over 20 years in the northeastern United States. We fitted single-visit dynamic occupancy models to data from Breeding Bird Atlases to quantify the magnitude of the effect of drivers of local colonization and extinction (e.g., climate, land cover, and amount of protected area) in heterogeneous landscapes that varied in the amount of area under protection. Colonization and extinction probabilities improved as the amount of protected area increased, but these effects were conditional on landscape context and species characteristics. In this forest-dominated region, benefits of additional land protection were greatest when both forest cover in a grid square and amount of protected area in neighboring grid squares were low. Effects did not vary with species’ migratory habit or conservation status. Increasing the amounts of land protection benefitted the range margins species but not the core range species. The greatest improvements in colonization and extinction rates accrued for forest birds relative to open-habitat or generalist species. Overall, protected areas stemmed extinction more than they promoted colonization. Our results indicate that land protection remains a viable conservation strategy despite changing habitat and climate, as protected areas both reduce the risk of local extinction and facilitate movement into new areas. Our findings suggest conservation in the face of climate change favors creation of new protected areas over enlarging existing ones as the optimal strategy to reduce extinction and provide stepping stones for the greatest number of species. 相似文献
Over-stabilisation and eutrophication affect many dune systems in north-west Europe. This leads to lower diversity of typical
dune species and an accumulation of soil nutrients. Existing management techniques to remove excess nutrients include mowing,
with removal of cuttings, and turf stripping. A new restoration technique called topsoil inversion or deep ploughing may also
be able to counter some of the negative effects of eutrophication. It simulates the burial of established soils with fresh
mineral sand, by inverting the soil profile. A trial was carried out on two small blocks of eutrophic dune grassland in North
Wales, UK. Nutrient-rich surface soils were buried beneath mineral sub-sand using a double-bladed plough, designed to plough
to depths of up to 100 cm. Results show that the organic soil horizons were buried to a depth of 80 cm, and covered with 40–50 cm
of mineral sand. The pH and organic matter of the surface layers became comparable to those of mobile dunes. Fifteen months
after ploughing, bare sand cover was still 70–90%, but significant sand loss through wind erosion resulted in a thinning of
the mineral sand over-burden, leaving the buried organic layer closer to the surface. Natural vegetation colonisation was
slow, with the first surviving plants observed after 8 months. The majority of species present at 15 months were present before
ploughing and had regenerated from rhizomes or root fragments. The effect of excluding disturbance caused by rabbits, people
and dogs was assessed within fenced areas. After 11 months, vegetation cover was greater in the fenced areas than in plots
exposed to disturbance, therefore disturbance replaced physical conditions as the dominant influence on plant growth and establishment.
These early results suggest the trial has been partially successful, but that topsoil inversion could be combined with other
methods such as turf stripping or by stabilisation of the ploughed surface by planting with pioneer species, depending on
the ultimate restoration goal. 相似文献
Leaves from three species of deciduous tree (oak, ash and hazel) were sampled at intervals through a growing season in a mature, mixed-deciduous woodland. Polycyclic aromatic hydrocarbon (PAH) concentrations remained within a small range for all species between May and September, deviating significantly only when increases in atmospheric concentrations of PAHs (notably from the 'Bonfire night' festival in early autumn) have been shown. We concluded that the influence of air concentrations was more important than meteorological conditions (temperature, humidity and rainfall) in determining plant concentrations of PAHs over a growing season. Concentrations of 4-, 5- and 6-ring PAHs were positively correlated with time for all species, but there were significant differences in the PAH profile between species sampled from the canopy (oak and ash) compared with the understorey (hazel). Oak and ash had similar PAH profiles, while hazel leaves had proportionally greater concentrations of the heavier molecular weight (4-, 5- and 6-ring) PAHs, and the ratios of these compounds to 3-ring PAHs was positively correlated with time. This affirms earlier work conducted on the same species in the same woodland, where we concluded that the canopy was filtering particles and attendant PAHs from air passing over or through it, and that these particles were transferred to the understorey and the woodland floor. 相似文献