Long-term changes in weed occurrence, yield and use of herbicides in maize in south-western Germany, with implications for the determination of economic thresholds

Weed Research ◽  
2014 ◽  
Vol 54 (5) ◽  
pp. 457-466 ◽  
Author(s):  
M Keller ◽  
N Böhringer ◽  
J Möhring ◽  
V Rueda-Ayala ◽  
C Gutjahr ◽  
...  
Keyword(s):  
Economic Thresholds ◽  
Long Term Changes ◽  
Western Germany

scholarly journals Long-term changes and maintenance of Phyllitis scolopendrium (L.) Newman population in the Wodąca Valley (the Cracow-Częstochowa Upland)

2011 ◽  
Vol 23 (1) ◽  
pp. 75-82 ◽  
Author(s):  
Stanisław Wika ◽  
Alicja Barć
Keyword(s):  
Association Studies ◽  
Long Term Changes ◽  
Quantitative Changes ◽  
Scientific Arguments

Long-term changes and maintenance of Phyllitis scolopendrium (L.) Newman population in the Wodąca Valley (the Cracow-Częstochowa Upland) The Cracow-Częstochowa Upland is an important mesoregion for the maintenance of Phyllitis scolopendrium (L.) Newman and its habitat with the Phyllitido-Aceretum Moor 1952 association. Studies in the Wodąca Valley focused on: the determination of the actual numerical force and quantitative changes in hart's-tongue resources between 1999 and 2009, a comparison of these results with literature, as well as on the indication of appropriate solutions for conservation purposes and for tourist exploitation of the Jurassic outcrops. Results of these studies provide scientific arguments for the maintenance of Phyllitis scolopendrium in the Wodąca Valley, on the edge of its European range.

scholarly journals The method of determination of the long-term trends in the F2 region independent of geomagnetic activity

2002 ◽  
Vol 20 (4) ◽  
pp. 511-521 ◽  
Author(s):  
A. D. Danilov
Keyword(s):  
Geomagnetic Activity ◽  
Regression Line ◽  
Close Relation ◽  
Layer Parameter ◽  
Modeling And Forecasting ◽  
Long Term Changes ◽  
Long Term Trends ◽  
Ap Index

Abstract. A detailed analysis of the f oF2 data at the Sverdlovsk station is performed to answer the question: whether the long-term trends of the F2-layer parameter detected recently are mainly due to the long-term changes in geomagnetic activity during the recent decades. Two methods to derive trends independent of geomagnetic activity are developed. It is found that both methods agree well and give a relative nongeomagnetic trend of about - 0.0015 per year (or an absolute nongeomagnetic trend of about - 0.015 MHz per year). The close relation of foF2 to Ap found by several authors is mainly due to a high correlation between the foF2 deviations from the regression line and year-to-year changes in the Ap index rather than to systematic long-term changes of Ap as has been suggested earlier.Key words. Ionosphere (ionospheric distances; modeling and forecasting)

scholarly journals Variability and trends in stratospheric NO<sub>2</sub> in Antarctic summer, and implications for the Brewer-Dobson circulation

2009 ◽  
Vol 9 (1) ◽  
pp. 837-863
Author(s):  
P. A. Cook ◽  
H. K. Roscoe
Keyword(s):  
Opposite Sign ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Full Time ◽  
Time Period ◽  
Long Term Changes ◽  
Alternative Settings ◽  
The Antarctic

Abstract. NO2 measurements during 1990–2007, obtained from a zenith-sky spectrometer in the Antarctic, are analysed to determine the long-term changes. The changes in midsummer should be indicative of any changes in the Brewer-Dobson circulation. An atmospheric photochemical box model and a radiative transfer model are used to improve the accuracy of determination of the vertical columns from the slant column measurements, and to deduce the amount of NOy from NO2. We find that the NO2 and NOy columns in midsummer have large inter-annual variability superimposed on a broad maximum in 2000, with little overall trend over the full time period. These changes are robust to a variety of alternative settings when determining vertical columns from slant columns or determining NOy from NO2. They suggest similar changes in speed of the Brewer-Dobson circulation but with opposite sign, i.e. a broad minimum around 2000.

Preparation And elemental analysis of ancient fibers

1987 ◽  
Vol 45 ◽  
pp. 410-411
Author(s):  
Allen Angel ◽  
Kathryn A. Jakes
Keyword(s):  
Cross Sections ◽  
Physical Structure ◽  
Energy Dispersive ◽  
Archaeological Sites ◽  
X Ray ◽  
Long Term Storage ◽  
Backscattered Electron ◽  
Electron Imaging

Fabrics recovered from archaeological sites often are so badly degraded that fiber identification based on physical morphology is difficult. Although diagenetic changes may be viewed as destructive to factors necessary for the discernment of fiber information, changes occurring during any stage of a fiber's lifetime leave a record within the fiber's chemical and physical structure. These alterations may offer valuable clues to understanding the conditions of the fiber's growth, fiber preparation and fabric processing technology and conditions of burial or long term storage (1).Energy dispersive spectrometry has been reported to be suitable for determination of mordant treatment on historic fibers (2,3) and has been used to characterize metal wrapping of combination yarns (4,5). In this study, a technique is developed which provides fractured cross sections of fibers for x-ray analysis and elemental mapping. In addition, backscattered electron imaging (BSI) and energy dispersive x-ray microanalysis (EDS) are utilized to correlate elements to their distribution in fibers.

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