Limatic variables that control development of stripe rust disease on winter wheat     

Stella Melugin Coakley  Roland F. Line 《Climatic change》1981,3(3):303-315

The frequency and severity of the stripe rust disease (caused byPuccinia striiformis) on winter wheat in the Pacific Northwest of the U.S.A. has increased since 1958 in association with climatic variation. From 1968–1979, rust intensities on ‘Gaines’ wheat were most highly correlated with accumulated negative degree days (NDD) between 1 December and 31 January and positive degree days (PDD) between 1 April and 30 June. NDD and PDD were calculated from a 7 °C base. Linear regression equations using NDD alone accounted for 76% of the variation in stripe rust. When NDD and PDD were combined, 88% of the variation in stripe rust was explained. When a growth index (GI), and NDD plus PDD were used as independent variables in a multiple regression analysis, 91% of the variation in disease was explained. Frequency of precipitation in June was correlated with stripe rust intensity, but when it was added to the multiple regression analysis, it explained less than an additional 1% of the variation. The relationships between NDD, PDD, and disease index help to explain why stripe rust was not severe from 1941 to 1957. Methods used in this research should be applicable to similar studies of the effect of climatic variation on other pests. This research was supported by a National Science Foundation Grant (ATM 76-21725), Climate Dynamics Program, Division of Atmospheric Sciences.  相似文献   

Actinide crystal-liquid partitioning for clinopyroxene and Ca₃(PO₄)₂     

T. Benjamin  W.R. Heuser  D.S. Burnett  M.G. Seitz 《Geochimica et cosmochimica acta》1980,44(9):1251-1264

Using fission and alpha track radiography techniques, we have measured partition coefficients (D) for the actinide elements Th, U and Pu between diopsidic clinopyroxene, whitlockite [β-Ca₃ (PO₄)₂] and silicate liquid at 20kbar. Equilibrium partitioning at the crystal-liquid interface is assumed, and corrections for actinide zoning have been applied to the measured D values. Reproducibility for both actinide and minor element D values is carefully examined as a criterion for crystal-liquid interface equilibrium. The data are mostly compatible with interface equilibrium except for experiments at high cooling rates ( ? 30 deg/hr). Partition coefficients for Th/U/Pu of about 0.002/0.002/0.06 are measured for clinopyroxene and 1.2/0.5/3.4 for whitlockite. At an oxygen fugacity of 10^?8.5, Pu is much more readily incorporated into the crystalline phases than is U or Th because of the importance of trivalent Pu. The D_Pu(cpx) is similar to D(cpx) of the light rare earths supporting the concept of Pu/(rare earth) dating.  相似文献   

Climatic effect of ENSO associated with landslide occurrence in the Central Andes, Mendoza Province, Argentina   总被引：1，自引：2，他引：1  

Stella M. Moreiras 《Landslides》2005,2(1):53-59

Temporal distribution of landslides can be verified by means of climatic anomalies linked to the ENSO phenomenon. An increasing number of landslides triggered by rainfall have been recorded during warm episodes (El Niño) in the Cordillera Frontal, and a decreasing number during cold episodes (La Niña), concluding that this geological province is mainly influenced by the Pacific Anticyclone. However, slope instability in the Precordillera, located east of the Cordillera Frontal, seems to be mainly influenced by the Atlantic Anticyclone. Analysis of variance shows that there is no significant difference between landslide records and cold-warm episodes, and a higher number of landslides were recorded in years linked to wet periods than during dry periods. Furthermore, the precipitation threshold value associated with landslide occurrence and antecedent precipitation are analysed.  相似文献   

The Pitman Canyon paleoseismic record: A re-evaluation of southern San Andreas Fault segmentation   总被引：2，自引：0，他引：2  

Gordon Seitz  Ray Weldon  II  Glenn P. Biasi 《Journal of Geodynamics》1997,24(1-4)

Correlation of three well-resolved paleoseismic records, including the Pitman Canyon site with its emerging record, presents a new possibility to understand fault segmentation. To be a useful concept, fault segment boundaries must be relatively stationary over multiple seismic cycles and must appear frequently in limiting the rupture extent of earthquakes; thus, sites on the same segment should share more paleoseismic events than those on different segments. A conclusive event correlation between sites is difficult or impossible due to dating uncertainties. However, often the data are adequate to preclude correlation and thus provide firm limits on rupture extent for those events. Thus clear non-correlations provide more information about segmentation than do unprovable potential correlations.The southern end of the most recent rupture in 1857, between Wrightwood and Pitman Canyon, is often used to define a segment boundary. However, there is an absence of significant non-correlation between the previous five Pitman Canyon events and the Wrightwood events. While both Pallett Creek and Wrightwood ruptured in 1857, only two of the previous five Wrightwood events can correlate with Pallett Creek events, which may or may not indicate that they actually do. These paleoseismic records do not support the existence of a segment boundary between Wrightwood and Pitman Canyon as defined by the 1857 rupture extent, suggesting a reevaluation of southern San Andreas Fault segmentation, and using historic ruptures to define segments in general.  相似文献   

Effects of inter-annual water storage variations on polar motion     

L. I. Fernández  H. Schuh  M. Schmidt  F. Seitz 《Geophysical Journal International》2007,169(1):12-18

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Living Shorelines Support Nearshore Benthic Communities in Upper and Lower Chesapeake Bay     

Theresa M. Davenport  Rochelle D. Seitz  Kathleen E. Knick  Nina Jackson 《Estuaries and Coasts》2018,41(1):197-206

Human population growth and sea-level rise are increasing the demand for protection of coastal property against shoreline erosion. Living shorelines are designed to provide shoreline protection and are constructed or reinforced using natural elements. While living shorelines are gaining popularity with homeowners, their ability to provide ecological services (e.g., habitat provision and trophic transfer) is not well understood, and information is needed to improve coastal and resource management decision-making. We examined benthic community responses to living shorelines in two case-study subestuaries of Chesapeake Bay using a before-after control-impact study design. At Windy Hill, a bulkhead was removed and replaced by three tombolos, sand fill, and native marsh vegetation. At Lynnhaven, 25 m of eroding marsh shoreline was stabilized with coir logs, sand fill, and native marsh vegetation. Communities of large (>?3 mm) infauna adjacent to living shorelines at both locations tended to increase in biomass by the end of the study period. Community compositions changed significantly following living shoreline construction at Windy Hill, reflecting a trend toward higher density and biomass of large bivalves at living shorelines compared to pre-construction. Increasing trends in density and biomass of clams and simultaneously decreasing density and decreasing trends in biomass of polychaetes suggest a transition toward stable infaunal communities at living shorelines over time, though longer-term studies are warranted.  相似文献   

Linking earthquake-triggered paleolandslides to their seismic source and to the possible seismic event that originated them in a portion of the Argentine Precordillera (31°–33°S)     

Junquera-Torrado  Sebastián  Moreiras  Stella M.  Rodríguez-Peces  Martín Jesús  Sepúlveda  Sergio A. 《Natural Hazards》2021,106(1):43-78

Natural Hazards - A total of 36 rock slides were selected for analysing a probable seismic source in the active Andean Precordillera (31°–33°S), the most seismic region of...  相似文献   

Future global SLR network evolution and its impact on the terrestrial reference frame     

Alexander Kehm  Mathis Bloßfeld  Erricos C. Pavlis  Florian Seitz 《Journal of Geodesy》2018,92(6):625-635

Satellite laser ranging (SLR) is an important technique that contributes to the determination of terrestrial geodetic reference frames, especially to the realization of the origin and the scale of global networks. One of the major limiting factors of SLR-derived reference frame realizations is the datum accuracy which significantly suffers from the current global SLR station distribution. In this paper, the impact of a potential future development of the SLR network on the estimated datum parameters is investigated. The current status of the SLR network is compared to a simulated potential future network featuring additional stations improving the global network geometry. In addition, possible technical advancements resulting in a higher amount of observations are taken into account as well. As a result, we find that the network improvement causes a decrease in the scatter of the network translation parameters of up to 24%, and up to 20% for the scale, whereas the technological improvement causes a reduction in the scatter of up to 27% for the translations and up to 49% for the scale. The Earth orientation parameters benefit by up to 15% from both effects.  相似文献   

Farewell to Harry M. Parker (1946–2019)     

Searston  Stella  Smith  Larry B.  Verly  Georges 《Mathematical Geosciences》2020,52(4):447-450

Mathematical Geosciences -  相似文献   

Rapid visual screening of soft-story buildings from street view images using deep learning classification     

Yu  Qian  Wang  Chaofeng  McKenna  Frank  Yu  Stella X.  Taciroglu  Ertugrul  Cetiner  Barbaros  Law  Kincho H. 《地震工程与工程振动(英文版)》2020,19(4):827-838

Rapid and accurate identification of potential structural deficiencies is a crucial task in evaluating seismic vulnerability of large building inventories in a region. In the case of multi-story structures, abrupt vertical variations of story stiffness are known to significantly increase the likelihood of collapse during moderate or severe earthquakes. Identifying and retrofitting buildings with such irregularities—generally termed as soft-story buildings—is, therefore, vital in earthquake preparedness and loss mitigation efforts. Soft-story building identification through conventional means is a labor-intensive and time-consuming process. In this study, an automated procedure was devised based on deep learning techniques for identifying soft-story buildings from street-view images at a regional scale. A database containing a large number of building images and a semi-automated image labeling approach that effectively annotates new database entries was developed for developing the deep learning model. Extensive computational experiments were carried out to examine the effectiveness of the proposed procedure, and to gain insights into automated soft-story building identification.

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