University of North Carolina at Wilmington

About: University of North Carolina at Wilmington is a education organization based out in Wilmington, North Carolina, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 3329 authors who have published 6797 publications receiving 186308 citations.

Estimation of age at maturation and growth of Atlantic green turtles (Chelonia mydas) using skeletochronology

Abstract: Despite the vast amount of research on threatened and endangered green turtle populations, some uncertainty regarding stage durations, growth rates, and age at maturation remains. We used skeletochronology to address this gap in knowledge for green turtle populations in the North Atlantic Ocean that use coastal waters along the southeastern U.S. as developmental habitat. Oceanic stage duration was estimated at 1–7 years ( $$ \overline{\text{X}} $$ = 3 years). Several growth models, including von Bertalanffy, logistic, Gompertz, and power functions were evaluated for describing sex-specific length-at-age data. Ages at maturation estimated using mean size at nesting for females from each genetic sub-population contributing juveniles to this neritic foraging area were 44 years (Florida), 42.5 years (Costa Rica), and 42 years (Mexico), which were higher than previously reported ages. This implies that nesting populations comprising primarily individuals utilizing foraging grounds in the southeastern U.S. may take longer to recover than previously estimated.

Alternation of factors limiting Phytoplankton production in the Cape Fear River estuary

Abstract: Phytoplankton nutrient limitation experiments were performed from 1994 to 1996 at three stations in the Cape Fear River Estuary, a riverine system originating in the North Carolina piedmont. Nutrient addition bioassays were conducted by spiking triplicate cubitainers with various nutrient combinations and determining algal response by analyzing chlorophyll a production and 14C uptake daily for 3 d. Ambient chlorophyll a, nutrient concentration, and associated physical data were collected throughout the estuary as well. At a turbid, nutrient-rich oligohaline station, significant responses to nutrient additions were rare, with light the likely principal factor limiting phytoplankton production. During summer at a mesohaline station, phytoplankton community displayed significant nitrogen (N) limitation, while both phosphorus (P) and N were occasionally limiting in spring with some N+P co-limitation. Light was apparently limiting during fall and winter when the water was turid and nutrient-rich, as well as during other months of heavy rainfall and runoff. A polyhaline station in the lower estuary had clearer water and displayed significant responses to nutrient additions during all enrichment experiments. At this site N limitation occurred in summer and fall, and P limitation (with strong N+P co-limitation) occurred in winter and spring. The data suggest there are two patterns controlling phytoplankton productivity in the Cape Fear system: 1) a longitudinal pattern of decreasing light limitation and increasing nutrient sensitivity along the salinity gradient, and 2) a seasonal alternation of N limitation, light limitation, and P limitation in the middle-to-lower estuary. Statistical analyses indicated upper watershed precipitation events led to increased flow, turbidity, light attenuation, and nutrient loading, and decreased chlorophyll a and nutrient limitation potential in the estuary. Periods of low rainfall and river flow led to reduced estuarine turbidity, higher chlorophyll a, lower ambient nutrients, and more pronounced nutrient limitation.

New Guinea has the world’s richest island flora

Abstract: New Guinea is the world’s largest tropical island and has fascinated naturalists for centuries1,2. Home to some of the best-preserved ecosystems on the planet3 and to intact ecological gradients—from mangroves to tropical alpine grasslands—that are unmatched in the Asia-Pacific region4,5, it is a globally recognized centre of biological and cultural diversity6,7. So far, however, there has been no attempt to critically catalogue the entire vascular plant diversity of New Guinea. Here we present the first, to our knowledge, expert-verified checklist of the vascular plants of mainland New Guinea and surrounding islands. Our publicly available checklist includes 13,634 species (68% endemic), 1,742 genera and 264 families—suggesting that New Guinea is the most floristically diverse island in the world. Expert knowledge is essential for building checklists in the digital era: reliance on online taxonomic resources alone would have inflated species counts by 22%. Species discovery shows no sign of levelling off, and we discuss steps to accelerate botanical research in the ‘Last Unknown’8. A catalogue of the vascular flora of New Guinea indicates that this island is the most floristically diverse in the world, and that 68% of the species identified are endemic to New Guinea.

Estimating the effects of carrier transit-time performance on logistics cost and service

Abstract: Joint determination of an appropriate transportation mode and an optimal inventory control policy is important in supply chain management We present a method of estimating the effects of carrier transit-time performance on logistics cost and service Unlike current approaches, this method enables users to develop accurate estimates when non-normal shapes characterize the probability distributions of both demand and lead time Additionally, the methodology includes two important refinements to the standard transportation-inventory model First, we relaxed the assumption that the shipping cost is a linear function of the order quantity Second, we treated transit time as a segment of lead time We used the gamma distribution to illustrate the flexibility of the method and developed an enhanced sensitivity-analysis tool for examining the effects of carrier transit time on both cost and service The methodology is appropriate for the transportation of service-sensitive, independent-demand inventory items controlled by a continuous review inventory system