Inventarisatie van macrozoobenthos in de Voordelta: dichtheden voor de najaarstocht van 1984 en de voorjaarstocht van 1985

In the frame of the Fore-Delta-research (see introduction and fig. 1) a soil animal inventarisation has been done. Three trips were made: fall 1984, spring 1985(1985-1) and fall 1985 (1985-2). In this report the densities of the first and the second trip are discussed. In the (sublittoral) research area, that has a surface of ca. 1200 km², 125 species were found, which are mentioned in table 1.The 14 most general species (vgl. Tables 16 and 27) are: -the chaetopods <i>Scoloplos armiger, Nephtys hombergii, Nephtys cirrosa, Magelona papillicornis, Spiophanes bombyx, Spio filicornis</i> and <i>Capitella capitata</i>; -the freshwater shrimp <i>Bathyporeia elegans</i> and <i>Urothoe poseidonis</i>; -the bivalves <i>Spisula subtruncata, Tellina fabula</i> and <i>Macoma balthica</i>; -the sea star <i>Ophiura texturata</i> and -the Nemertinea group). The approach is summarised in figure 2: the strategy of sample taking was adjusted to the results of the previous trip.By TWINSPAN-classification of density data of 1984 it showed a special pattern could be distinguished, as far as soil animal composition and densities were concerned, on two similar stations. This made a strata-classification (6 strata) based on soil animal data possible. At the start of the project this was not yet possible based on available soil or soil animal data. At the second trip, a “stratified random” sampling was then done to be able to estimate accurately the densities per stratum. Reliability intervals for the geometric average density are calculated. The data are log-transformed, then the average of the observations is determined and this value is then transformed back for the individual strata and for the entire area (see table 27, figures 29-35 and the figures of appendix 4a). A strong correlation between the geometric average density and the frequency of the species was found (see 4 and 6). During the comparison of the TWINSPAN-classification of the data of the first two BOVO-trips, similar special patterns were discovered, stable zonation be it (see figures 25-28). The strata classification, deduced from the second trip and used for the third, is refined (10 strata), compared to the previous strata classification (6 strata) based on the first trip (see overlays 1 and 2). The northern strata (fine sand with low-average mud content) are relatively rich in species and individuals per sample (see figures 52 and 53). The Wester Scheldt mouth (with a high mud content in the mainly fine sand soils and the highly suppressive dust content in the water column) and parts of the Easter Scheldt mouth (where, in accordance to the high speed of streams, low mud contents are found in the middle grove sandy soil) showed few species and individuals per sample in 1984-1985 (see figures 23 and 24). Per stratum an abiotic description is given (see 3 and table 9). Per species correlations were sought in a graphic way with measured soil factors and the depth, and the ecologic distribution was researched, based on data from the second trip (see 5 and e.g. the figures 38, 41 and 45). On the entire density-dataset (1984 and 1985-1 apart) an ordination (DECORANA) technique has been applied, and more research for order-correlation with measured soil factors and the depth (see 2.5). These proved to be statistically significant correlated with one or more of the DECORANA-ordination-axes (see 5). Extremely high correlations were found with the mud content (and the group of correlated variables) (see table 26 and fig. 49). In relation to the application of different techniques for sample taking (Reineck-box corer and Van Veen-grab), these have been compared to each other on penetration-depth and density estimations for soil animals (see 2). The Box-Corer penetrated (mean 26 cm) noticeably deeper than the Van Veen-grab (mean 15 cm) (see table 4 en figures 3a en 3b). Only for the polychaetes <i>Magelona papillicornis</i> and <i>Nephtys cirrosa</i> and for the amphipode <i>Urothoe poseidonis</i> the density (p< 0.05) was significantly higher in the box. This also counts for the total density of all species, for the polychaetes and for the Amphipoda (cfr. table 5). In the discussion (see 6) a.o. a comparison is considered with data from Wolff from the period 1958-1969. From this we can conclude that sea species such as <i>Tellina fabula</i> have become more common in the Fore Delta. In the report a selection of the most remarkable figures is presented ; the others can be found in some appendix. (These can be consulted at the library of the NIOZ in Texel and at RWS-DGW in Middelburg)

Reconstruction of Bandlimited Functions from Unsigned Samples

We consider the recovery of real-valued bandlimited functions from the absolute values of their samples, possibly spaced nonuniformly. We show that such a reconstruction is always possible if the function is sampled at more than twice its Nyquist rate, and may not necessarily be possible if the samples are taken at less than twice the Nyquist rate. In the case of uniform samples, we also describe an FFT-based algorithm to perform the reconstruction. We prove that it converges exponentially rapidly in the number of samples used and examine its numerical behavior on some test cases

Characterization of individual airborne particles in Taiyuan City, China

Taiyuan, the capital of Shanxi province, China, is one of the most polluted cities in the world. To characterize the ambient particulate pollution, samples of particulates with aerodynamic diameter less than 10 µm (PM(10)) were collected during a 6-day campaign. Individual particles were analyzed by Scanning Electron Microscope with Energy-Dispersive Spectrometer (SEM-EDS) to determine their chemical composition. Meanwhile, photomicrographs were obtained from SEM to aid in particles’ source identification. The lumped data from SEM-EDS were subjected to hierarchical cluster analysis (HCA) to sort out particle types chemically. HCA combined with SEM photomicrographs allowed us to identify 20 different particle types, namely (in order of particle frequency), soil/fly ash particles, coal-burning, sulfur-rich, and iron-rich particles, gypsum, syngenite, quartz, cement, silicon sulfide, siliconferro alloy, calcium-rich particles, ferrochromium alloy, ammonium sulfate and chloride, iron-zinc, ammonium chloride, molybdenum-rich, potassium sulfate, dolomite, lead sulfate, and copper-rich particles. Their possible origins and pathways are suggested. The majority of the particles seem to originate from coal combustion, which conforms to Taiyuan’s industrial structure

Studies of acid deposition and its effects in two small catchments in Hunan, China

International audienceAcid deposition and its effects were studied by analysing the chemistry in precipitation, stream water, soil water and soils in two catchments in Hunan. One site, Linkesuo (denoted LKS), is on the outskirts of Changsha, the provincial capital of Hunan, the other (Bailutang, denoted BLT) on the outskirts of Chenzhou in southern Hunan. Volume-weighted average pH values and sulphate concentrations in wet deposition were 4.58 (BLT) and 4.90 (LKS) and 174 ?molc L-1 and 152 ?molc L-1, respectively. Wet deposition of sulphate has been estimated as 4.3 gS m-2yr-1 and 3.4 gS m-2yr-1 at BLT and LKS, respectively. Estimates of the corresponding total depositions (dry + wet) are 6.1 gS m-2yr-1 and 5.3 gS m-2yr-1. In precipitation and throughfall, sulphate was the major anion and calcium the major cation. In stream and soil water, nitrate was slightly higher than sulphate on an equivalent basis and magnesium (Mg) not much lower than calcium (Ca). Important soil properties, such as soil pH, soil organic matter (SOM) content, exchangeable acidic cations, exchangeable base cations, effective cation exchange capacity (CECe), base saturation (BS), and aluminium (Al) and iron (Fe) pools, were determined for five forest soil profiles (consisting of four horizons) in each of the two catchments. The soils in BLT are generally more acid, have lower BS and higher Al and Fe pools than the LKS soils. The Al- and Fe-pools were generally higher in the topsoils (i.e. the O and A horizons) than in deeper soils (i.e. E and B horizons) especially at the most acidic site (BLT). There are significant correlations between Fe-pools and the corresponding Al-pools in both catchments except between the amorphous Feox and Alox. Considering the long-term high deposition of sulphate, there is a risk of future ecological damage due to acidification, especially in the BLT catchment, although vegetation damage has yet to be observed in the catchments. This condition appears to be representative of a large part of Hunan. Keyword: acid deposition, soil acidification, catchment, Al-pools, Fe-pools, Hunan</p

Divided Differences & Restriction Operator on Paley-Wiener Spaces PWtaupPW_{tau}^{p} for N−N-Carleson Sequences

For a sequence of complex numbers $\Lambda$ we consider the restriction operator $R_{\Lambda}$ defined on Paley-Wiener spaces $PW_{\tau}^{p}$ ($1<p<\infty$). Lyubarskii and Seip gave necessary and sufficient conditions on $\Lambda$ for $R_{\Lambda}$ to be an isomorphism between $PW_{\tau}^{p}$ and a certain weighted $l^{p}$ space. The Carleson condition appears to be necessary. We extend their result to $N-$Carleson sequences (finite unions of $N$ disjoint Carleson sequences). More precisely, we give necessary and sufficient conditions for $R_{\Lambda}$ to be an isomorphism between $PW_{\tau}^{p}$ and an appropriate sequence space involving divided differences

Cornerstones of Sampling of Operator Theory

This paper reviews some results on the identifiability of classes of operators whose Kohn-Nirenberg symbols are band-limited (called band-limited operators), which we refer to as sampling of operators. We trace the motivation and history of the subject back to the original work of the third-named author in the late 1950s and early 1960s, and to the innovations in spread-spectrum communications that preceded that work. We give a brief overview of the NOMAC (Noise Modulation and Correlation) and Rake receivers, which were early implementations of spread-spectrum multi-path wireless communication systems. We examine in detail the original proof of the third-named author characterizing identifiability of channels in terms of the maximum time and Doppler spread of the channel, and do the same for the subsequent generalization of that work by Bello. The mathematical limitations inherent in the proofs of Bello and the third author are removed by using mathematical tools unavailable at the time. We survey more recent advances in sampling of operators and discuss the implications of the use of periodically-weighted delta-trains as identifiers for operator classes that satisfy Bello's criterion for identifiability, leading to new insights into the theory of finite-dimensional Gabor systems. We present novel results on operator sampling in higher dimensions, and review implications and generalizations of the results to stochastic operators, MIMO systems, and operators with unknown spreading domains

Predation and caribou populations

Predation, especially wolf (Canis lupus) predation, limits many North American caribou (Rangifer tarandus) populations below the density that food resources could sustain. The impact of predation depends on the parameters for the functional and numerical response of the wolves, relative to the potential annual increment of the caribou population. Differences in predator-avoidance strategies largely explain the major differences in caribou densities that occur naturally in North America. Caribou migrations that spatially separate caribou from wolves allow relatively high densities of caribou to survive. Non-migratory caribou that live in areas where wolf populations are sustained by alternate prey can be eliminated by wolf predation

Ecosystem management and the conservation of caribou habitat in British Columbia

Woodland caribou (Rangifer tarandus caribou) in British Columbia inhabit a wide variety of forest ecosystems. Numerous research projects have provided information that has been used to develop caribou habitat management recommendations for different areas. Recently, the province has implemented guidelines to protect biodiversity that are based on an ecosystem management strategy of mimicking natural forest conditions. There is a great deal of similarity between caribou management recommendations and biodiversity recommendations within different forest types. In mountain caribou habitat, both approaches recommend maintaining a landscape dominated by old and mature forests, uneven-aged management, small cutblocks, and maintaining mature forest connectivity. In northern caribou habitat, both approaches recommend maintaining some older stands on the landscape (but less than for mountain caribou), even-aged management, and a mosaic of large harvest units and leave areas. The ecosystem management recommendations provide a useful foundation for caribou habitat conservation. More detailed information on caribou and other management objectives can then be used to fine-tune those recommendations

Introduction to the Population Ecology of North American Caribou

Bergerud has discussed how major differences in caribou density across North America appear to be related to the impact of wolf (Canis lupus) predation, and the strategies used by caribou to avoid wolves. Caribou living in areas without wolves usually occur at high densities and are regulated by competition for food. In this session, we asked the presenters to discuss the population ecology of different caribou herds in North America and to evaluate if they fit the general model

Analytic Representation of Finite Quantum Systems

A transform between functions in R and functions in Zd is used to define the analogue of number and coherent states in the context of finite d-dimensional quantum systems. The coherent states are used to define an analytic representation in terms of theta functions. All states are represented by entire functions with growth of order 2, which have exactly d zeros in each cell. The analytic function of a state is constructed from its zeros. Results about the completeness of finite sets of coherent states within a cell are derived