363 research outputs found
Gonadotropin releasing hormone stimulates the formation of inositol phosphates in rat anterior pituitary tissue
Genetic Heterogeneity in a Cyclical Forest Pest, the Southern Pine Beetle, Dendroctonus frontalis, is Differentiated Into East and West Groups in the Southeastern United States
The southern pine beetle, Dendroctonus frontalis Zimmerman (Coleoptera: Curculionidae) is an economically important pest species throughout the southeastern United States, Arizona, Mexico, and Central America. Previous research identified population structure among widely distant locations, yet failed to detect population structure among national forests in the state of Mississippi. This study uses microsatellite variation throughout the southeastern United States to compare the southern pine beetle's pattern of population structure to phylogeographic patterns in the region, and to provide information about dispersal. Bayesian clustering identified east and west genetic groups spanning multiple states. The east group had lower heterozygosity, possibly indicating greater habitat fragmentation or a more recent colonization. Significant genetic differentiation (θST = 0.01, p < 0.0001) followed an isolation-by-distance pattern (r = 0.39, p < 0.001) among samples, and a hierarchical AMOVA indicated slightly more differentiation occurred between multi-state groups. The observed population structure matches a previously identified phylogeographic pattern, division of groups along the Appalachian Mountain/Apalachicola River axis. Our results indicate that the species likely occurs as a large, stable metapopulation with considerable gene flow among subpopulations. Also, the relatively low magnitude of genetic differentiation among samples suggests that southern pine beetles may respond similarly to management across their range
Stimulation of phospholipid hydrolysis and arachidonic acid mobilization in human uterine decidua cells by phorbol ester
GROND - a 7-channel imager
We describe the construction of GROND, a 7-channel imager, primarily designed
for rapid observations of gamma-ray burst afterglows. It allows simultaneous
imaging in the Sloan g'r'i'z' and near-infrared bands. GROND was
commissioned at the MPI/ESO 2.2m telescope at La Silla (Chile) in April 2007,
and first results of its performance and calibration are presented.Comment: 25 pages, 21 figs, PASP (subm); version with full-resolution figures
at http://www.mpe.mpg.de/~jcg/GROND/grond_pasp.pd
Who Controls the Looking Glass? Towards a Conversational Understanding of Organizational Theatre
This paper presents a longitudinal study of interactive organizational theatre. Managers of a large home care organization used 30 instances of organizational theatre over a one year period to effect organizational change. We found that neither management, who had hoped that employees would accept and internalize the messages accompanying the play, nor employees, who used the liminal spaces to express their own take on the organization’s issues, achieved their aims directly. Yet a year later, organizational performance and satisfaction were significantly improved—much of this was attributed to the play. To explain this, we develop a conversational theory of change, one where ‘conversation pieces’ are central. We also speculate on the properties that conversation pieces and conversational systems like organizational theatre must have if they are to effect change.N/
The influence of anthropogenic nitrogen loading and meteorological conditions on the dynamics and toxicity of Alexandrium fundyense blooms in a New York (USA) estuary
Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Harmful Algae 9 (2010): 402-412, doi:10.1016/j.hal.2010.02.003.The goal of this two-year study was to explore the role of nutrients and
climatic conditions in promoting reoccurring Alexandrium fundyense blooms in the
Northport-Huntington Bay complex, NY, USA. A bloom in 2007 was short and small (3
weeks, 103 cells L-1 maximal density) compared to 2008 when the A. fundyense bloom,
which persisted for six weeks, achieved cell densities >106 cells L-1 and water column
saxitoxin concentrations >2.4 x 104 pmol STX eq. L-1. During the 2008 bloom, both
deployed mussels (used as indicator species) and wild soft shell clams became highly
toxic (1,400 and 600μg STX eq./100g shellfish tissue, respectively) resulting in the
closure of shellfish beds. The densities of benthic A. fundyense cysts at the onset of this
bloom were four orders of magnitude lower than levels needed to account for observed
cell densities, indicating in situ growth of vegetative cells was responsible for elevated
bloom densities. Experimental enrichment of bloom water with nitrogenous compounds,
particularly ammonium, significantly increased A. fundyense densities and particulate
saxitoxin concentrations relative to unamended control treatments. The δ15N signatures
(12 to 23‰) of particulate organic matter (POM) during blooms were similar to those of
sewage (10 to 30‰) and both toxin and A. fundyense densities were significantly
correlated with POM δ15N (p < 0.001). These findings suggest A. fundyense growth was
supported by a source of wastewater such as the sewage treatment plant which discharges
into Northport Harbor. Warmer than average atmospheric temperatures in the late winter
and spring of 2008 and a cooler May contributed to an extended period of water column
temperatures optimal for A. fundyense growth (12 – 20ºC), and thus may have also
contributed toward the larger and longer bloom in 2008. Together this evidence suggests
sewage-derived N loading and above average spring temperatures can promote intense
and toxic A. fundyense blooms in estuaries.This work was supported by a grant from EPA’s Long Island Sound Study, New York
Sea Grant, and the New York State Department of Environmental Conservation (to CJG)
and from the NOAA Sea Grant Program (Grant No. NA06OAR4170021 (R/B-177)) to
DMA
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