Entwicklung von Enzymimmunoassays zum Nachweis von Phenoxycarbonsäure-Herbiziden in Trink- und Grundwässern Development of Enzyme Immunoassays for the Detection of Phenoxycarboxylic Acid Herbicides in Drinking Water and Groundwater     

W. Weber  K. Rubach 《洁净——土壤、空气、水》1994,22(2):53-59

Competitive solid phase enzyme immunoassays using polyclonal antibodies were developed for the detection of the phenoxycaboxylic acids MCPB [4-(4-chloro-2-methylphenoxy)butyric acid], Mecoprop [2-(4-chloro-2-methylphenoxy)propionic acid], and 2,4-D [(2,4-dichloro-phenoxy)acetic acid] in drinking water and ground water. The carrier protein for the immunization was bovine serum albumin, horseradish peroxidase conjugates were employed as enzyme tracer. For the three antisera, the optimization of detection limits and test sensitivities was our first consideration. For the mecoprop and 2,4-D antisera, the strongest influences were the pH value and the ionic strength, as much as the use of enzyme tracers with lower affinities. The MCPB antiserum reacted with 2,4-DB[4-(2,4-dichlorophenoxy)butyric acid] with equal specificity, either could be detected at 0.02 μg/L (80% B/B₀), middle of the test (50 B/B₀) lying at 0.1 μg/L. The detection limit with mecoprop antiserum was optimized to 0.02 μg/L, the prescribed limit for drinking water of 0.1 μg/L ling at 60 % B/B₀. The strongest cross-reactivity was found for mecoprop methyl ester. MCPB. 2,4-DB, and dichloroprop have crossreactivities of 50%, 6.7%, and 6.3%, respectively. The 2,4-D antiserum reacts less sensitively with 2,4-D, the detection limit being 0.4 μg/L. The 2,4-D isooctyl ester and 2,4-D methyl ester demonstrate as cross-reacting compounds high cross-reactivites of 3630% and 2230%. The cross-reactions of the compounds 2,4-DB, MCPB, and MCPA [(4-chloro-2-methylphenoxy)acetic acid] lie at 52%, 69%, and 41%. 100 ground water tests were spiked within laboratory. All positive samples were correctly identified. Falsely negative results did not appear.  相似文献   

On the seasonal variation of local relationships between temperature,temperature range,sunshine and cloudiness     

G. R. Weber 《Theoretical and Applied Climatology》1994,50(1-2):15-22

Summary At Berlin-Dahlem, monthly single station data on cloudiness, sunshine duration, mean, maximum and minimum temperature is statistically analyzed for the time period 1955–1993.It is found that sunshine duration varies inversely with cloud cover; cloud cover correlates negatively with temperature range. Cloud cover correlates negatively with temperature between March and September, and positively with temperature during the remaining months.Between 1955 und 1993, there are no significant changes in temperature range in any month but June and September, when a decline occurred.Sunshine declined significantly in March, June and September. Trends between 1955 and 1987 indicate a larger decline of sunshine and decline in temperature range than between 1955 and 1993.Locally, sulfate deposition, which may be taken as an indicator of the atmospheric sulfate load, decreased by more than a third between the mid-1950s and the late 1980s. Therefore, at Berlin, the observed increase of cloudiness (decrease of sunshine duration) between the 1950s and the late 1980s went parallel to the measured decrease of sulfate deposition.With 3 Figures  相似文献   

Limnological response to the Laacher See eruption (LSE) in an annually laminated Allerød sediment sequence from the Nahe palaeolake,northern Germany     

Stefan Dreibrodt  Sascha Krüger  Jan Weber  Ingo Feeser 《Boreas: An International Journal of Quaternary Research》2021,50(1):167-183

This paper presents evidence for a limnological response to the Laacher See eruption (LSE) as detected in lake sediments from Nahe, northern Germany. The sediment section of the Allerød period dating to between 13 422 and 12 708 cal. a BP is preserved in annual laminations. Within this section, the LSE was identified as a cryptotephra layer (12 944±44 cal. a BP). Microfacies analysis, continuous high-resolution geochemical measurements and pollen analyses enabled a high-resolution reconstruction of environmental change. The older part of the Allerød (c. 13 422 to 12 943 cal. a BP) was characterized by relatively stable sedimentation conditions. Evidence for windier conditions dating to c. 13 160 to 13 080 cal. a BP probably reflects the Gerzensee oscillation. Pronounced changes of the lake sedimentation followed the LSE. Four unusually thick varves with increased amounts of allochthonous material indicate serious disturbance of the local environment immediately after the LSE, related to increased storminess and/or the occurrence of high intensity rainfall events. A pronounced reduction of biogenic silica accumulation for c. 60 years after the LSE could reflect a period of acidification. Indications of a simultaneous lake level increase until c. 60 years after the LSE are in line with the supposed reduced evapotranspiration associated with cooler conditions. About 120 years after the LSE, increased oxygen access at the lake bottom, allochthonous input and Cl fluxes point to an onset of increasingly stronger westerly winds, probably as a long-term response to the LSE. This supports the idea of a southward shift of the mid-latitude westerlies wind system within the interval between the LSE and the beginning of the Younger Dryas. The pace of the southwards shift of this wind system decreased from 10 km a⁻¹ in the initial phase (40–120 years after LSE) to 6 km a⁻¹ in the later phase (120–200 years after LSE).  相似文献   

Hierarchically nested river landform sequences. Part 1: Theory          下载免费PDF全文

Gregory B. Pasternack  Dastagir Baig  Matthew D. Weber  Rocko A. Brown 《地球表面变化过程与地形》2018,43(12):2510-2518

Past river classifications use incommensurate typologies at each spatial scale and do not capture the pivotal role of topographic variability at each scale in driving the morphodynamics responsible for evolving hierarchically nested fluvial landforms. This study developed a new way to create geomorphic classifications using metrics diagnostic of individual processes the same way at every spatial scale and spanning a wide range of scales. We tested the approach on flow convergence routing, a geomorphically and ecologically important process with different morphodynamic states of erosion, routing, and deposition depending on the structure of nondimensional topographic variability. Five nondimensional landform types with unique functionality represent this process at any flow; they are nozzle, wide bar, normal channel, constricted pool, and oversized. These landforms are then nested within themselves by considering their longitudinal sequencing at key flows representing geomorphically important stages. A data analysis framework was developed to answer questions about the stage‐dependent spatial structure of topographic variability. Nesting permutations constrain and reveal how flow convergence routing morphodynamics functions in any river the framework is applied to. The methodology may also be used with other physical and biological datasets to evaluate the extent to which the patterning in that data is influenced by flow convergence routing. Copyright © 2018 John Wiley & Sons, Ltd.  相似文献   

Nano‐Powdered Calcium Carbonate Reference Materials: Significant Progress for Microanalysis?     

Klaus Peter Jochum  Dieter Garbe‐Schnberg  Marina Veter  Brigitte Stoll  Ulrike Weis  Michael Weber  Federico Lugli  Anna Jentzen  Ralf Schiebel  Jasper A. Wassenburg  Dorrit E. Jacob  Gerald H. Haug 《Geostandards and Geoanalytical Research》2019,43(4):595-609

Homogeneity, mass fractions of about forty trace elements and Sr isotope composition of Ca carbonate reference materials (RMs) between original and nano‐powdered pellets are compared. Our results using nanosecond and femtosecond LA‐(MC)‐ICP‐MS show that the nano‐pellets of the RMs MACS‐3NP, JCp‐1NP and JCt‐1NP are about a factor of 2–3 more homogeneous than the original samples MACS‐3, JCp‐1 and JCt‐1, and are therefore much more suitable for microanalytical purposes. With the exception of Si, the mass fractions of the synthetic RM MACS‐3 agree with its fine‐grained analogue MACS‐3NP. Very small, but significant, differences between original and nano‐pellets are observed in the RMs JCp‐1 and JCt‐1 for some trace elements with very low contents, indicating the need for re‐certification. Strontium mass fractions in the analysed RMs are high (1500–7000 mg kg^?1), and their isotope compositions determined by LA‐MC‐ICP‐MS in the original and the nano‐pellets agree within uncertainty limits.  相似文献   

History of globulettes in the Milky Way     

Tiia Grenman  Erik Elfgren  Hans Weber 《Astrophysics and Space Science》2018,363(2):28

Globulettes are small (radii \({<} 10\) kAU) dark dust clouds, seen against the background of bright nebulae. A majority of the objects have planetary mass. These objects may be a source of brown dwarfs and free floating planetary mass objects in the galaxy. In this paper we investigate how many globulettes could have formed in the Milky Way and how they could contribute to the total population of free floating planets. In order to do that we examine H-alpha images of 27 H II regions. In these images, we find 778 globulettes.We find that a conservative value of the number of globulettes formed is \(5.7\times 10^{10}\). If 10% of the globulettes form free floating planets then they have contributed with \(5.7\times 10^{9}\) free floating planets in the Milky Way. A less conservative number of globulettes would mean that the globulettes could contribute \(2.0\times 10^{10}\) free floating planets. Thus the globulettes could represent a non-negligible source of free floating planets in the Milky Way.  相似文献   

Relative suitability of indices derived from Landsat ETM+ and SPOT 5 for detecting fire severity in sagebrush steppe     

J. Norton  N. Glenn  M. Germino  K. Weber  S. Seefeldt 《International Journal of Applied Earth Observation and Geoinformation》2009,11(5):360-367

Remote sensing indices of burn area and fire severity have been developed and tested for forest ecosystems, but not sparsely vegetated, desert shrub-steppe in which large wildfires are a common occurrence and a major issue for land management. We compared the performance of remote sensing indices for detecting burn area and fire severity with extensive ground-based cover assessments made before and after the prescribed burning of a 3 km² shrub-steppe area. The remote sensing indices were based on either Landsat 7 ETM+ or SPOT 5 data, using either single or multiple dates of imagery. The indices delineating burned versus unburned areas had better overall, User, and Producer's accuracies than indices delineating levels of fire severity. The Soil Adjusted Vegetation Index (SAVI) calculated from SPOT had the greatest overall accuracy (100%) in delineating burned versus unburned areas. The relative differenced Normalized Burn Ratio (RdNBR) using Landsat ETM+ provided the highest accuracies (73% overall accuracy) for delineating fire severity. Though SPOT's spatial resolution likely conferred advantages for determining burn boundaries, the higher spectral resolution (particularly band 7, 2.21 μm) of Landsat ETM+ may be necessary for detecting differences in fire severity in sparsely vegetated shrub-steppe.  相似文献   

High‐pressure metamorphic evolution of eclogite and associated metapelite from the Chuacús complex (Guatemala Suture Zone): Constraints from phase equilibria modelling coupled with Lu‐Hf and U‐Pb geochronology          下载免费PDF全文

Roberto Maldonado  Bodo Weber  Fernando Ortega‐Gutiérrez  Luigi A. Solari 《Journal of Metamorphic Geology》2018,36(1):95-124

As is common in suture zones, widespread high‐pressure rocks in the Caribbean region reached eclogite facies conditions close to ultrahigh‐pressure metamorphism. Besides eclogite lenses, abundant metapelitic rocks in the Chuacús complex (Guatemala Suture Zone) also preserve evidence for high‐pressure metamorphism. A comprehensive petrological and geochronological study was undertaken to constrain the tectonometamorphic evolution of eclogite and associated metapelite from this area in central Guatemala. The integration of field and petrological data allows the reconstruction of a previously unknown segment of the prograde P–T path and shows that these contrasting rock types share a common high‐pressure evolution. An early stage of high‐pressure/low‐temperature metamorphism at 18–20 kbar and 530–580°C is indicated by garnet core compositions as well as the nature and composition of mineral inclusions in garnet, including kyanite–jadeite–paragonite in an eclogite, and chloritoid–paragonite–rutile in a pelitic schist. Peak high‐pressure conditions are constrained at 23–25 kbar and 620–690°C by combining mineral assemblages, isopleth thermobarometry and Zr‐in‐rutile thermometry. A garnet/whole‐rock Lu‐Hf date of 101.8 ± 3.1 Ma in the kyanite‐bearing eclogite indicates the timing of final garnet growth at eclogite facies conditions, while a Lu‐Hf date of 95.5 ± 2.1 Ma in the pelitic schist reflects the average age of garnet growth spanning from an early eclogite facies evolution to a final amphibolite facies stage. Concordant U‐Pb LA‐ICP‐MS zircon data from the pelitic schist, in contrast, yield a mean age of 74.0 ± 0.5 Ma, which is equivalent to a U‐Pb monazite lower‐intercept age of 73.6 ± 2.0 Ma in the same sample, and comparable within errors with a less precise U‐Pb lower‐intercept age of 80 ± 13 Ma obtained in post‐eclogitic titanite from the kyanite‐bearing eclogite. These U‐Pb metamorphic ages are interpreted as dating an amphibolite facies overprint. Protolith U‐Pb zircon ages of 167.1 ± 4.2 Ma and 424.6 ± 5.0 Ma from two eclogite samples reveal that mafic precursors in the Chuacús complex originated in multiple tectonotemporal settings from the Silurian to Jurassic. The integration of petrological and geochronological data suggests that subduction of the continental margin of the North American plate (Chuacús complex) beneath the Greater Antilles arc occurred during an Albian‐Cenomanian pre‐collisional stage, and that a subsequent Campanian collisional stage is probably responsible of the amphibolite facies overprint and late syncollisional exhumation.  相似文献   

Geoarchaeology of the Mockingbird Gap (Clovis) site,Jornada del Muerto,New Mexico     

Vance T. Holliday  Bruce B. Huckell  Robert H. Weber  Marcus J. Hamilton  William T. Reitze  James H. Mayer 《Geoarchaeology》2009,24(3):348-370

The Mockingbird Gap site is one of the largest Clovis sites in the western United States, yet it remains poorly known after it was tested in 1966–1968. Surface collecting and mapping of the site revealed a dense accumulation of Clovis lithic debris stretching along Chupadera Draw, which drains into the Jornada del Muerto basin. We conducted archaeological testing and geoarchaeological coring to assess the stratigraphic integrity of the site and gain clues to the paleoenvironmental conditions during the Clovis occupation. The 1966–1968 excavations were in stratified Holocene eolian sand and thus that assemblage was from a disturbed content. An intact Clovis occupation was found elsewhere in the site, embedded in the upper few centimeters of a well‐developed buried Bt horizon formed in eolian sand, representing the regional Clovis landscape. Coring in Chupadera Draw revealed ∼11 m of fill spanning the past ∼11,000 ¹⁴C years. The stratified deposits provide evidence of flowing and standing water on the floor of the draw during Clovis times, a likely inducement to settlement. © 2009 Wiley Periodicals, Inc.  相似文献   

Differential rotation in compact objects with hyperons and delta isobars     

Delaney Farrell  Fridolin Weber  Jia Jie Li  Armen Sedrakian 《Astronomische Nachrichten》2024,345(2-3):e230160

Neutron stars may experience differential rotation on short, dynamical timescales following extreme astrophysical events like binary neutron star mergers. In this work, the masses and radii of differentially rotating neutron star models are computed. We employ a set of equations of states for dense hypernuclear and $\mathrm{\Delta }$-admixed-hypernuclear matter obtained within the framework of CDF theory in the relativistic Hartree-Fock (RHF) approximation. Results are shown for varying meson- $\mathrm{\Delta }$ couplings, or equivalently the $\mathrm{\Delta }$-potential in nuclear matter. A comparison of our results with those obtained for nonrotating stars shows that the maximum mass difference between differentially rotating and static stars is independent of the underlying particle composition of the star. We further find that the decrease in the radii and increase in the maximum masses of stellar models when $\mathrm{\Delta }$-isobars are added to hyperonuclear matter (as initially observed for static and uniformly rotating stars) persist also in the case of differentially rotating neutron stars.  相似文献