Meteorological Influences on Respirable Fragment Release from Chinese Elm Pollen

2006 ◽  
Vol 40 (9) ◽  
pp. 690-696 ◽  
Author(s):  
Ann G. Miguel ◽  
Philip E. Taylor ◽  
James House ◽  
M. Michael Glovsky ◽  
Richard C. Flagan
Author(s):  
B. L. Redmond ◽  
Christopher F. Bob

The American Elm (Ulmus americana L.) has been plagued by Dutch Elm Disease (DED), a lethal disease caused by the fungus Ceratocystis ulmi (Buisman) c. Moreau. Since its initial appearance in North America around 1930, DED has wrought inexorable devastation on the American elm population, triggering both environmental and economic losses. In response to the havoc caused by the disease, many attempts have been made to hybridize U. americana with a few ornamentally less desirable, though highly DED resistant, Asian species (mainly the Siberian elm, Ulmus pumila L., and the Chinese elm Ulmus parvifolia Jacq.). The goal is to develop, through breeding efforts, hybrid progeny that display the ornamentally desirable characteristics of U. americana with the disease resistance of the Asian species. Unfortunately, however, all attempts to hybridize U. americana have been prevented by incompatibility. Only through a firm understanding of both compatibility and incompatibility will it be possible to circumvent the incompatibility and hence achieve hybridization.


Kerntechnik ◽  
2008 ◽  
Vol 73 (3) ◽  
pp. 113-117 ◽  
Author(s):  
H. Dombrowski ◽  
F. Wissmann

2004 ◽  
Vol 43 (12) ◽  
pp. 1887-1899 ◽  
Author(s):  
Daniel J. Leathers ◽  
Daniel Graybeal ◽  
Thomas Mote ◽  
Andrew Grundstein ◽  
David Robinson

Abstract A one-dimensional snowpack model, a unique airmass identification scheme, and surface weather observations are used to investigate large ablation events in the central Appalachian Mountains of North America. Data from cooperative observing stations are used to identify large ablation events within a 1° latitude × 1° longitude grid box that covers the majority of the Lycoming Creek basin in northern Pennsylvania. All 1-day ablation events greater than or equal to 7.6 cm (3 in.) are identified for the period of 1950 through 2001. Seventy-one events are identified, and these days are matched with a daily airmass type derived using the Spatial Synoptic Classification technique. Average meteorological characteristics on ablation days of each airmass type are calculated in an effort to understand the diverse meteorological influences that led to the large ablation events. A one-dimensional mass and energy balance snowpack model (“SNTHERM”) is used to calculate surface/atmosphere energy fluxes responsible for ablation under each airmass type. Results indicate that large ablation events take place under diverse airmass/synoptic conditions in the central Appalachians. Five airmass types account for the 71 large ablation events over the 52-yr period. Forty-three of the events occurred under “moist” airmass types and 28 under “dry” airmass conditions. Large ablation events under dry airmass types are driven primarily by daytime net radiation receipt, especially net solar radiation. These events tend to occur early and late in the snow cover season when solar radiation receipt is highest and are characterized by relatively clear skies, warm daytime temperatures, and low dewpoint temperatures. Moist airmass types are characterized by cloudy, windy conditions with higher dewpoint temperatures and often with liquid precipitation. During these events sensible heat flux is most often the dominant energy flux to the snowpack during ablation episodes. However, in many cases there is also a significant input of energy to the snowpack associated with condensation. Combinations of high sensible and latent heat fluxes often result in extreme ablation episodes, similar to those witnessed in this area in January 1996.


EDIS ◽  
2018 ◽  
Vol 2018 (3) ◽  
Author(s):  
Juanita Popenoe ◽  
Caroline G Roper Warwick ◽  
Richard C Beeson, Jr.

This series of Key Plant, Key Pests publications are designed for Florida gardeners, horticulturalists and landscape professionals to help identify common pests associated with common Florida flora. This publication, the second in the Key Plant, Key Pests Series, helps identify the most common pests found on the Chinese Elm (Ulmus parvifolia). This publication provides information and general management recommendations for anthracnose or black elm spot, powdery mildew, trunk canker, borers, eriophyid mites and leaf beetles.https://edis.ifas.ufl.edu/ep559


2016 ◽  
Vol 16 (8) ◽  
pp. 4867-4883 ◽  
Author(s):  
N. Sobanski ◽  
M. J. Tang ◽  
J. Thieser ◽  
G. Schuster ◽  
D. Pöhler ◽  
...  

Abstract. Through measurements of NO2, O3 and NO3 during the PARADE campaign (PArticles and RAdicals, Diel observations of mEchanisms of oxidation) in the German Taunus mountains we derive nighttime steady-state lifetimes (τss) of NO3 and N2O5. During some nights, high NO3 (∼ 200 pptv) and N2O5 (∼ 1 ppbv) mixing ratios were associated with values of τss that exceeded 1 h for NO3 and 3 h for N2O5 near the ground. Such long boundary-layer lifetimes for NO3 and N2O5 are usually only encountered in very clean/unreactive air masses, whereas the PARADE measurement site is impacted by both biogenic emissions from the surrounding forest and anthropogenic emissions from the nearby urbanised/industrialised centres. Measurement of several trace gases which are reactive towards NO3 indicates that the inferred lifetimes are significantly longer than those calculated from the summed loss rate. Several potential causes for the apparently extended NO3 and N2O5 lifetimes are examined, including additional routes to formation of NO3 and the presence of a low-lying residual layer. Overall, the most likely cause of the anomalous lifetimes are related to the meteorological conditions, though additional NO3 formation due to reactions of Criegee intermediates may contribute.


2006 ◽  
pp. 100-116
Author(s):  
Cesare Lombroso

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