Species distributions are limited by a complex array of abiotic and biotic factors. In general, abiotic (climatic) factors are thought to explain species' broad geographic distributions, while biotic factors regulate species' abundance patterns at local scales. We used species distribution models to test the hypothesis that a biotic interaction with a tree, the Colombian oak (Quercus humboldtii...

different layers of acorn (quercus infectoria), hull, seed coat and seed kernel were analyzed for determination of chemical composition. the results of the preliminary analysis showed that acorn contained more than 65% carbohydrates, 8% lipid and 10% tannin among other constituents. the fatty acid composition of the seed oil was determined using thin layer chromatography and comparing with ...

The relative contribution of nitrogen (N) reserves from seeds or uptake by the roots to the growth and N content of young seedlings has received little attention. In this study, we investigated the contribution of N from the acorn or uptake by the roots to the N content of holm oak (Quercus ilex L.) seedlings and determined if remobilization of acorn N was affected by nutrient availability in t...

Background: Foraging movements of animals shape their efficiency in finding food and their exposure to the environment while doing so. Our goal was to test the optimal foraging theory prediction that territorial acorn woodpeckers (Melanerpes formicivorus) should forage closer to their ‘central place’ in years of high resource availability and further afield when resources are less available. We...

We used 21 years of acorn data from visual surveys of oak (Quercus spp.) trees (n 1⁄4 20,113) conducted in western North Carolina, USA, to develop predictive equations for hard-mast indices (HMIs) based on the proportion of trees bearing acorns (PBA). We calculated PBA using visual estimates of the percentage of oak crown with acorns (PCA), assigning acorn presence if PCA 33.5%. The proportion ...

After 38 years of longevity (1970 to 2008), including huge growth over its last decade, in 2008 and 2009 the Association of Community Organizations for Reform Now (ACORN) was rocked by an embezzlement scandal and two controversies and declined precipitously. By the spring of 2010, all city and statewide ACORN operations had either disaffiliated from the national organization or collapsed altoge...

ACORN (Agent-based Community Oriented Retrieval Network) is a multi-agent system which uses agents to provide information across inter-net/intranet networks. In this report, we adapt the ACORN architecture for its performance evaluation on single and multiple servers, running on single and multiple machines. In order to evaluate the performance of ACORN, we introduce a novel concept of multiple...

Although the consequences of cotyledon removal have been widely studied in oaks producing large acorns, we have little knowledge of at what level cotyledons can be removed without affecting acorn survival and seedling development. In this study, we aimed to test the hypothesis that the amount of energy reserves in cotyledons is more than the demands of seedlings and that large acorns can tolera...

We measured patterns of spatial synchrony in growth and reproduction by oaks using direct acorn surveys, published data on acorn production, and tree-ring chronologies. The two data sets involving acorn production both indicate that acorn crops are detectably synchronous over areas of at least 500 to 1,000 km not only within individual species but among species that require the same number of y...

We propose a mathematical model for fault-tolerant routing based on acyclic orientations, or acorns, of the underlying network G = (V; E). The acorn routing model applies routing tables that store the set of parent pointers associated with each out-neighborhood de ned by the acorn. Unlike the standard single-parent sink-tree model, which is vulnerable to faults, the acorn model a ords a full re...