409 research outputs found

    Population assessment of the vermilion snapper, Rhomboplites aurorubens, from the Southeastern United States

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    Changes in the age structure and population size of vermilion snapper, Rhornboplites aurorubens, from North Carolina through the Florida Keys were examined using records of landings and size frequencies of fish from commercial, recreational, and headboat fisheries from 1986-1996. Population size in numbers at age was estimated for each year by applying separable virtual population analysis (SVPA) to the landings in numbers at age. SVPA was used to estimate annual, age-specific fishing mortality (F) for four levels of natural mortality (M = 0.20, 0.25, 0.30, and 0.35). Although landings of vermilion snapper for the three fisheries have declined, minimum fish size regulations have resulted in an increase in the mean size of fish landed. Age at entry and age at full recruitment were age-1 andage-3 fDr 1986-1991, compared with age-1 and age-4, respectively, for 1992-1996. Levels of mortality from fishing (F) ranged from 0.38 - 0.61 for the entire period. Current spawning potential ratio (SPR) is 21% or 27% depending on the natural mortality estimate. SPR could be raised to 30% or 40% with a reduction in F, or by increasing the age at entry to the fisheries. The latter could be enhanced now if fishermen, particularly recreational, comply with minimum size regulations. However, released fish mortality, modeled in the assessment at 27%, will continue to make the achievement of 30% and 40% SPR more difficult. (PDF contains 63 pages

    Archive What I See Now Bringing Institutional Web Archiving Tools to the Individual Researcher

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    PDF of a powerpoint presentation from the 2014 National Endowment for the Humanities (NEH) Office of Digital Humanities (ODH) Project Directors\u27 Meeting in Washington D. C., September 15, 2014. Also available form Slideshare.https://digitalcommons.odu.edu/computerscience_presentations/1031/thumbnail.jp

    Age, Growth and Natural Mortality of Blackfin Snapper Lutjanus buccanella from the Southeastern United States and U. S. Caribbean

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    We determined ages of Blackfin Snapper (Lutjanus buccanella Cuvier 1828; n = 622) collected from the southeastern United States coast and U.S. Caribbean from 1979–2015 using sectioned sagittal otoliths. Opaque zones were determined to be annular, forming March – July (peaking in April–June). Blackfin Snapper ranged from 1–27 years and from 180–609 mm total length (TL). Body size relationships for Blackfin Snapper were: TL = 1.09 FL + 0.81 (n = 203, r2 = 0.99); FL = 0.91 TL + 3.38 (n = 203, r2 = 0.99); TL = 1.23 SL + 14.27 (n = 83, r2 = 0.97); FL = 1.14 SL + 10.84 (n = 83, r2 = 0.99); W = 7.79 x 10—9 TL3.09 (n = 216); and W = 9.54 x 10—9 FL3.11 (n = 228). The von Bertalanffy growth equation was: Lt = 549 (1 — e—0.20 (t +1.51)) (n = 622). Point estimate of natural mortality was M = 0.16, while age—specific estimates of M ranged from 0.65–0.21/y for ages 1–27. This study presents the first findings of life history parameters for Blackfin Snapper from the Atlantic waters off the southeastern United States and U.S. Caribbean

    Mapping Regional Forest Evapotranspiration and Photosynthesis by Coupling Satellite Data with Ecosystem Simulation

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    Mapping Regional Forest Evapotranspiration and Photosynthesis by Coupling Satellite Data With Ecosystem Simulatio

    Multiregional Emergence of Mobile Pastoralism and Nonuniform Institutional Complexity across Eurasia

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    In this article I present a new archaeological synthesis concerning the earliest formation of mobile pastoralist economies across central Eurasia. I argue that Eurasian steppe pastoralism developed along distinct local trajectories in the western, central, and (south)eastern steppe, sparking the development of regional networks of interaction in the late fourth and third millennia BC. The “Inner Asian Mountain Corridor” exemplifies the relationship between such incipient regional networks and the process of economic change in the eastern steppe territory. The diverse regional innovations, technologies, and ideologies evident across Eurasia in the mid-third millennium BC are cast as the building blocks of a unique political economy shaped by “nonuniform” institutional alignments among steppe populations throughout the second millennium BC. This theoretical model illustrates how regional channels of interaction between distinct societies positioned Eurasian mobile pastoralists as key players in wide-scale institutional developments among traditionally conceived “core” civilizations while also enabling them to remain strategically independent and small-scale in terms of their own sociopolitical organization. The development of nonuniform institutional complexity among Eurasian pastoralists demonstrates a unique political and economic structure applicable to societies whose variable political and territorial scales are inconsistent with commonly understood evolutionary or corporate sociopolitical typologies such as chiefdoms, states, or empires

    An Inverse Agonist Ligand of the PTH Receptor Partially Rescues Skeletal Defects in a Mouse Model of Jansen’s Metaphyseal Chondrodysplasia

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    Jansen’s metaphyseal chondrodysplasia (JMC) is a rare disease of bone and mineral ion physiology that is caused by activating mutations in PTHR1. Ligand‐independent signaling by the mutant receptors in cells of bone and kidney results in abnormal skeletal growth, excessive bone turnover, and chronic hypercalcemia and hyperphosphaturia. Clinical features further include short stature, limb deformities, nephrocalcinosis, and progressive losses in kidney function. There is no effective treatment option available for JMC. In previous cell‐based assays, we found that certain N‐terminally truncated PTH and PTHrP antagonist peptides function as inverse agonists and thus can reduce the high rates of basal cAMP signaling exhibited by the mutant PTHR1s of JMC in vitro. Here we explored whether one such inverse agonist ligand, [Leu11,dTrp12,Trp23,Tyr36]‐PTHrP(7‐36)NH2 (IA), can be effective in vivo and thus ameliorate the skeletal abnormalities that occur in transgenic mice expressing the PTHR1‐H223R allele of JMC in osteoblastic cells via the collagen‐1α1 promoter (C1HR mice). We observed that after 2 weeks of twice‐daily injection and relative to vehicle controls, the IA analog resulted in significant improvements in key skeletal parameters that characterize the C1HR mice, because it reduced the excess trabecular bone mass, bone marrow fibrosis, and levels of bone turnover markers in blood and urine. The overall findings provide proof‐of‐concept support for the notion that inverse agonist ligands targeted to the mutant PTHR1 variants of JMC can have efficacy in vivo. Further studies of such PTHR1 ligand analogs could help open paths toward the first treatment option for this debilitating skeletal disorder. © 2019 American Society for Bone and Mineral Research.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154322/1/jbmr3913-sup-0001-Supinfo.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154322/2/jbmr3913.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154322/3/jbmr3913_am.pd
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