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1.
Ten years of vegetation dynamics in two rivulets in Lower Saxony (FRG)   总被引:1,自引:0,他引:1  
The vegetation dynamics in six permanent plots in two lowland rivulets of the Federal Republic of Germany are analyzed. The year-to-year change in species cover is displayed by means of tables. In each site there are core species (both hydrophytes and helophytes) which have been able to successfully reproduce within the sampling plots over the total observation period. There are also transient hydrophytes which regularly become washed in from the upper course, and transient helophytes growing permanently into the river from the banks.A numerical analysis of the performance of the 12 most frequent and abundant hydrophytes in relation to various independent variables was carried out using canonical correspondence analysis. There is no directional temporal variation within the vegetation data set. The hydrochemical variables were almost constant within the observation period. Rainfall in summer has some influence via discharge and turbidity. Most of the variance in the data set is explained by the position of the sites along the rivers. Most of the residual variance can be explained by a binary disturbance variable. The processes observed can mostly be explained from life history characteristics of the dominant species, particularySparganium emersum, Ranunculus peltatus andPotamogeton natans. The spatial scale of the study site was relatively adequate. A smaller size would have produced noisy data (suggesting erratic change), while a greater size would have produced no change at all. The adequate temporal scale for observation is the comparison of the yearly maxima because of the seasonality of most of the species. An exact prediction of dominance and species composition of the following year is impossible.  相似文献   

2.
Serum samples with lower temperature-dependent antibody with low avidity to C100-3 (HCV) antigen were found in 0.19% of 23,197 voluntary blood donors at this blood center. They showed positive C100-3 antibody activity at 24 C but not at 37 C. The antibody activity bound to C100-3 antigen at lower temperature disappeared after incubation for 60 min at 37 C or treatment with 8 M urea. Other markers of hepatitis C virus infection, especially the presence of HCV-RNA were demonstrated in some of these serum samples and the importance of this phenomenon is discussed with regard to virus screening of blood donors for hepatitis C.  相似文献   

3.
In the diluvial plain of Lower Saxony ( = Niedersachsen) two types of alder fen woods are found: alder swamp woods (alder carrs) with a more changing water table and inundations in winter, and alder spring woods without hibernal inundation and a more or less constant water table. While all alder swamp woods are Alnion forests, the alder spring woods can be devided into Alnion and Alno-Ulmion forests.All Alnion forests in the diluvial plain of Lower Saxony belong to the association Carici elongatae-Alnetum Schwick. 1933. This association can be devided into three subassociations, C. el.-Al. betuletosum Bodeux 1955, C. el.-Al. typicum Meijer Drees 1936 and C. el.-Al. cardaminetosum Meijer Drees 1936.Low pH-values and high C/N-ratios of the soil are good indicators to distinguish the Carici elongatae-Alnetum betuletosum from the other two subassociations. Humus contents has a tendency to decrease in the sequence C. el.-Al. betuletosum > C. el.-Al. typicum > C. el.-Al cardaminetosum, but is no reliable factor for classification of a single plot. Differences in annual groundwater level variations cause a floristical differentiation only within alderwoods of meso- to eutrophic sites. Here a nearly constant water table or at least no hibernal inundation leads to a Carici elongatae-Alnetum cardaminetosum, while sites which are inundated in winter carry the Carici elongatae-Alnetum typicum. On oligotrophic sites both, swamp and spring woods belong to the Carici elongatae-Alnetum betuletosum.The subdivision of the Carici elongatae-Alnetum for the whole lowlands of northern Central Europe is generally the same as for Lower Saxony. Source reference: This paper was presented as a poster with the title Alnion Forests in Lower Saxony (FRG)-Syntaxonomical position and ecological requirements on the IAVS-Symposium Forests of the World, Upsala 20.–27.8.1989.  相似文献   

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Since the first sporadic occurrences of grey wolves (Canis lupus) west of the Polish border in 1996, wolves have shown a rapid population recovery in Germany. Wolves are known to avoid people and wolf attacks on humans are very rare worldwide. However, the subjectively perceived threat is considerable, especially as food-conditioned habituation to humans occurs sporadically. Lower Saxony (Germany) has an exceedingly higher human population density than most other regions with territorial wolves; thus, the potential for human–wolf conflicts is higher. Using hunters’ wildlife survey data from 455 municipalities and two years (2014–2015) and data from the official wolf monitoring (557 confirmed wolf presences and 500 background points) collected between 2012–2015, grey wolf habitat selection was modelled using generalized additive models with respect to human population density, road density, forest cover and roe deer density. Moreover, we tested whether habitat use changed in response to human population and road density between 2012/2013 and 2014/2015.Wolves showed a preference for areas of low road density. Human population density was less important as a covariate in the model of the survey data. Areas with higher prey abundance (5–10 roe deer/km2) and areas with >20% forest cover were preferred wolf habitats. Wolves were mostly restricted to areas with the lowest road and human population densities. However, between the two time periods, avoidance of human density decreased significantly.Recolonization of Germany is still in its early stages and it is unclear where this process will halt. To-date authorities mainly concentrate on monitoring measures. However, to avoid conflict, recolonization will require more stringent management of wolf populations and an improved information strategy for rural populations.  相似文献   

6.
Blood samples from 94 coal tits (Parus ater), 56 great tits (Parus major) and 219 pied flycatchers (Ficedula hypoleuca), caught between 1993 and 2002 at two localities in Lower Saxony, Germany, were examined for haemosporidian infection by parasite-specific polymerase chain reaction (PCR). A simple PCR targeting the 18 SSU rRNA gene of the parasites was used for rapid screening of the samples and generated a total infection prevalence of 20.6% (76/369): 6.8% (n = 15) of the pied flycatchers, 19.1% (n = 18) of the coal tits and 76.8% (n = 43) of the great tits were infected. The positive specimens were re-examined by a cytochrome b gene-directed nested PCR producing significantly longer DNA fragments (approx. 520 bp) that were sequenced and analysed against GenBank-deposited nucleotide sequences. In various numbers (once to 30 times), a total of 13 parasitic DNA sequences differing from 2.9 to 8.5% (13–45 nucleotides) were demonstrated in the three bird species. Due to similarities of 98–100% with GenBank entries, 11 sequences could be assigned to Plasmodium sp. and two to the genus Haemoproteus. In summary, 57 birds were infected with Plasmodium and 19 with Haemoproteus, corresponding to 15.4 and 5.1% of all birds examined, and to 75 and 25% of all birds tested positive. As the only defined species, Haemoproteus majoris was identified in 17 great tits.  相似文献   

7.
Francisella tularensis is the aetiological agent of tularemia. Hares, rabbits, and small rodents are the main hosts, but humans can be infected and develop severe clinical symptoms. In Germany, tularemia in humans was a rare disease during the last four decades, but since 2005, this zoonosis seems to be re-emerging. However, only very little is known about the prevalence in the host populations. Therefore, in a study performed from 2006 to 2009, we investigated 2,121 brown hares (Lepus europaeus) and 41 European rabbits (Oryctolagus cuniculus) located in Lower Saxony, Germany for the occurrence of this zoonotic bacterium by PCR and bacterial culture. F. tularensis subsp. holarctica was detected in an average of 1.1% of these animals. Two hot spots were found in northern Lower Saxony indicating outbreaks of tularemia even in hares. This study demonstrates the occurrence of F. tularensis subsp. holarctica within the hare population in Germany. Hunters, medical practitioners, and public health professionals should be aware of the risk which could come from this zoonotic agent especially in the hot spot areas.  相似文献   

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In this presentation, the mycotoxin levels—as analysed by the analytical centre for mycotoxin surveillance of the state food laboratory (LAVES Braunschweig)—for approximately 500 food samples are reported. The samples were collected in the year 2009 at retail in the German federal state of Lower Saxony. Aflatoxin and ochratoxin A were analysed in dried fruits, spices, cereals and tree nuts. Ochratoxin A was detected in all samples of dried vine fruits, at levels up to 8.1 μg/kg. Aflatoxins and ochratoxin A were also found in nutmeg and curry powder: the maximum regulatory levels for aflatoxins were exceeded in 25% of the nutmeg samples. Nearly all samples of basmati rice contained aflatoxins, although at levels below the maximum regulatory level in all but one sample. Aflatoxins were also detected in about 50% of hazelnut samples, in 20% of the samples the maximum levels was exceeded (maximum 23.2 μg/kg). In contrast, aflatoxin contents in pistachios were surprisingly low. Fusarium toxins were analysed in cereals and cereal products such as flour, bread, and pasta. Deoxynivalenol (DON) was the predominant toxin found in these samples: DON was found in about 40% of the samples, although the maximum levels were not exceeded (max. 418 μg/kg). Fumonisins (FBs) and zearalenone (ZEA) were specifically analysed in maize products (snacks, flour and oil). Most of these samples (80%) were positive, but at levels not exceeding the maximum levels. Maximum levels were 98 μg/kg (ZEA) and 577 μg/kg (sum of FB1 and FB2). Ergot alkaloids (six major alkaloids) were analysed in rye flour, and approximately 50% were positive. The highest concentration of ergot alkaloids was 1,063 μg/kg; the predominant alkaloids were ergotamine and ergocristine. In conclusion, the results indicate that continuous and efficient control measures for mycotoxins in a wide range of critical foods are necessary to ensure compliance with maximum levels. Although the mycotoxin levels in the vast majority of samples were below maximum levels, year-to-year variation and changes in the production of relevant commodities may result in a different picture in the future.  相似文献   

11.
Summary Geological, papaeontological and microfacies studies in the Lower Cambrian carbonate complex of the G?rlitz Synclinorium (eastern Germany/Saxony/Lusatian region) provide new data for the fossil content, depositional history and palaeogeography. The Lower Cambrian of the G?rlitz Synclinorium belongs to the facies zones 5, 7 and 8 ofWilson (1975)-platform rim with connections to the open ocean and to the restricted platform areas. An extraordinarily rich fauna was found with elements which are in some cases new for Europe (Rhombocorniculum cancellatum Cobbold,Fordilla sibirica Krasilova, Calodiscus lobatus Hall,Archaeooides granulatus Qian,Archiasterella pentactina Sdzuy,Allonia sp.,Obliquatheca aldanica Sysoiev,Conotheca circumflexa Missarzhevsky,Microcornus elongatus Missarzhevsky,Lenalituus sp.,Pelagiella cf.lorenzi Kobayashi,Beshtashella sp.,Comluella sp.,Cambroclavithidae gen. et sp. indet., Helcionellidae gen. et sp., indet. Eocrinoidea gen. et sp. indet.) This fauna indicates Lower Cambrian (higher Atdabanian/Botomian) age and reveals palaeobiogeographical connections to the Siberian Platform, to the Mediterranean area and to China. A somewhat new stratigraphical subdivision of the Lower Cambrian sequence (Zwetau Formation) is described. New units are established within the Ludwigsdorf Member (the carbonatic lower part of the sequence), the ‘Lower Ludwigsdorf Member’ (massive dolostone) and the ‘Upper Ludwigsdorf Member’ (bedeed limestones and their equivalents). The subsequentLusatiops Member is subdivided intoSerrodiscus Bed (claystones) andLusatiops Bed (siltstones).  相似文献   

12.
During a combined research project at several stations along the Lower Saxony coast (German North Sea) antifouling biocides were analysed in water, sediment and biota. Pathological alterations in blue mussel, Pacific oyster and periwinkle found in the harbour of Norderney and a reference station are presented here and discussed on the background of chemical analyses. The molluscan species from the reference station Borkum East flat did not show any pathological effects in central organs, except those provoked by an infestation in the gastro-intestinal tract by the copepod Mytilicola intestinalis and trematode larvae. In most animals, the metacercaria were found in the interstitial tissue without any inflammatory reaction. In a minor number of specimens, an inflammatory reaction in the mucosa and sub-mucosa of the intestine occurred in association with Mytilicola infestation. These reactions may be evoked through mechanical irritation of the gut epithelium, metabolic products of the parasites or invading bacteria. In contrast to the observed pathological changes of mussels, oysters and periwinkles in Norderney harbour were not found to be associated with parasitic infestation. The most prominent pathological alterations were observed in the digestive system and in the gonad. In the gastro-intestinal tract inflammatory reactions, atrophy and necrosis of tubules in the mid gut gland were most pronounced in spring at the beginning of the pleasure boat season in the Pacific oyster and to a minor degree in the blue mussel and the periwinkle. The latter displayed additional inflammatory and necrotic processes in the gills. Especially in the gonad, an elevated resorption rate of gametes was present in the Pacific oyster and in the periwinkle. In addition, impact of organotin compounds was reflected in an intersex index of up to 1.4 in Littorina littorea in coincidence with masculinization of the reproductive organs.  相似文献   

13.
With the antigen expressed in yeast from a cDNA clone encoding a non-structural region of newly discovered hepatitic C virus (HCV) genome, the prevalence of HCV antibody in people in Thailand was investigated. Antibody was detected in 2.6% of healthy blood donors and in 2.8% of healthy pregnant women. These prevalence rates were higher than those reported previously from Japan, USA and European countries. Among community-acquired, sporadic cases of acute and chronic non-A, non-B hepatitis, however, only 5.7% and 15.4% were shown to possess the antibody, respectively. Among hepatocellular carcinoma patients who were negative for hepatitis B surface antigen in the sera, 11.1% had antibody to HCV. These seroepidemiological data suggest that HCV plays an important role as an etiological agent in Thailand; however, other agents must also be involved in etiologic agents of viral hepatitis and chronic liver disease.  相似文献   

14.
L Yuan  W Lau  J Thipphawong  M Kasenda  F Xie  J Bevilacqua 《CMAJ》1997,156(7):985-990
OBJECTIVE: To determine the diphtheria and tetanus antitoxin levels among blood donors in Toronto. DESIGN: Cross-sectional seroprevalence study. SETTING: Two fixed-site blood-donation clinics in Toronto from September to November 1994. PARTICIPANTS: Blood donors 20 years of age or older were eligible to participate; of the 781 eligible donors, 710 (90.9%) participated in the study. MAIN OUTCOME MEASURES: Diphtheria and tetanus antitoxin levels and factors associated with disease susceptibility, such as vaccination history, country of birth, age and sex. A diphtheria antitoxin level lower than 0.01 lU/mL and a tetanus antitoxin level lower than 0.15 lU/mL were considered nonprotective. RESULTS: Among the participants, 147 (20.7%) had a diphtheria antitoxin level in the nonprotective range, and 124 (17.5%) had a tetanus antitoxin level that was nonprotective. Increasing age and lack of written vaccination records were associated with susceptibility to the 2 diseases. Birth outside Canada was significantly related to tetanus susceptibility. CONCLUSION: Adults over 50 years of age who did not know their vaccination history were the least likely to be protected against diphtheria and tetanus. The greatest benefit of any immunization strategy would be gained by targeting this group.  相似文献   

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16.
Khomutova  T. E.  Shirshova  L. T.  Tinz  S.  Rolland  W.  Richter  J. 《Plant and Soil》2000,219(1-2):13-19
The conversion of natural forests into cultivated lands causes changes of the carbon cycle, which are of particular importance for fragile landscapes. We examined the mobilization of organic carbon in undisturbed soil monoliths of a deciduous forest, a pine plantation, and a pasture under constant temperature (20°C) and moisture via a leaching experiment. Soil percolation was performed with synthetic rainfall solution (pH 5) for a period of 20 weeks. The leachates of the first 12 weeks were analyzed for the pH, DOC content, light absorbance at 260 and 330 nm. At the end of the experiment soil pH, total carbon, C:N ratio, content of fractions of humic substances were examined. After 20 weeks of the leaching experiment the decrease of soil total Corg reached 29, 23, and 50% in soil monoliths of deciduous forest, pasture, and coniferous forest, respectively. The amounts of DOC removed constituted 6.4, 3.8, and 6.2% of initial soil Corg, respectively. Cumulative values of DOC production decreased in the sequence coniferous forest > deciduous forest > pasture. UV-Vis absorptivities of DOC were similar in both forests and differed from those in pasture. UV-Vis characteristics showed that DOC composition changed during the experiment. The intensive soil percolation caused alterations of the properties of soil organic matter, in particular a change of fraction composition of humic substances occurred.  相似文献   

17.
A population-based case-control study on risk factors for childhood malignancies was used to investigate a previously reported association between elevated indoor radon concentrations and childhood cancer, with special regard to leukaemia. The patients were all children suffering from leukaemia and common solid tumours (nephroblastoma, neuroblastoma, rhabdomyosarcoma, central nervous system (CNS) tumours) diagnosed between July 1988 and June 1993 in Lower Saxony (Germany) and aged less than 15 years. Two population-based control groups were matched by age and gender to the leukaemia patients. Long-term (1 year) radon measurements were performed in those homes where the children had been living for at least 1 year, with particular attention being paid to those rooms where they had stayed most of the time. Due to the sequential study design, radon measurements in these rooms could only be done for 36% (82 leukaemias, 82 solid tumours and 209 controls) of the 1038 families initially contacted. Overall mean indoor radon concentrations (27 Bq m–3) were low compared with the measured levels in other studies. Using a prespecified cutpoint of 70 Bq m–3, no association with indoor radon concentrations was seen for the leukaemias (odds ratio (OR): 1.30; 95% confidence interval (95% CI): 0.32–5.33); however, the risk estimates were elevated for the solid tumours (OR: 2.61; 95% CI: 0.96–7.13), mainly based on 6 CNS tumours. We did not find any evidence for an association between indoor radon and childhood leukaemia, which is in line with a recently published American case-control study. There is little support for an association with CNS tumours in the literature. Received: 14 December 1998 / Accepted in revised form: 10 June 1999  相似文献   

18.
A former clay quarry near Schöningen in Lower Saxony exposes deposits dating from the upper half of the Ladinian. There are several bone beds in this quarry, which differ partly in their faunal composition and in the preservation of the fossils. One of these bone beds contains many morphologically different teeth of mainly terrestrial tetrapods and a variety of remains of actinopterygians, chondrichthyans and dipnoans. The tetrapod teeth are described in this paper. A precise taxonomic determination is not possible, but the material appears to contain two temnospondyls, a synapsid and several species of archosaurs. Some tooth morphotypes can not be assigned, even at a high taxonomic level. The tooth assemblage, which is described in this paper, is briefly compared with published and unpublished data on teeth from the Middle and Upper Keuper of Central Europe.  相似文献   

19.
Background: The recently discovered hepatitis G virus (HGV) belongs, as hepatitis C virus (HCV), to the Flaviviridae family. HGV has been isolated from the serum of patients with non A-E hepatitis. However, the association of HGV with hepatitis is uncertain.Objective: To determine the HGV prevalence in blood donors and in patients with liver disease and to evaluate a possible correlation between HGV infection and liver disease.Study design: Sera from a total of 113 consecutive patients with chronic liver disease were submitted to a series of liver enzymes and function tests and analyzed for the presence of HBsAg, anti-HBs, anti-HBc, anti-HCV, HCV RNA and HGV RNA. Prevalence of HGV RNA was determined in a group of 87 blood donors.Results: Nine (10%) sera from blood donors and 15 (13%) sera from patients with chronic liver disease were HGV RNA positive. Some 28 (25%) patients were HCV RNA positive, with genotypes 1a, 1b and 3 present in 10, 12 and 5 patients, respectively. A total of 20 (18%) patients were HBsAg carriers. Five (4%) patients were double infected (one with HBV+HCV, one with HBV+HGV and three with HCV+HGV).Conclusion: The proportion (10%) of HGV-infected blood donors was very high when compared with other countries. The results did not allow to establish HGV as an etiologic agent for chronic liver disease. The parenteral route was the presumed means of HGV transmission for only one-third of the patients.  相似文献   

20.

Aim

The aim of this study was to determine the seroprevalence of Hepatitis E virus (HEV) among blood donors in southwest Switzerland.

Background

HEV is recognized as a food-borne disease in industrialized countries, transmitted mainly through pork meat. Cases of transmission through blood transfusion have also been reported. Recent studies have revealed seroprevalence rates of 13.5%, 16.6% and 20.6% among blood donors in England, France and Denmark, respectively.

Methods

We analyzed 550 consecutive blood donor samples collected in the region of Lausanne, canton of Vaud, Switzerland, for the presence of anti-HEV IgG, using the MP Diagnostics HEV ELISA kit. For each donor, we documented age, sex and alanine aminotransferase (ALT) value.

Results

The study panel was composed of 332 men (60.4%) and 218 women (39.6%). Overall, anti-HEV IgG was found in 27 of 550 samples (4.9%). The seroprevalence was 5.4% (18/332) in men and 4.1% (9/218) in women. The presence of anti-HEV IgG was not correlated with age, gender or ALT values. However, we observed a peak in seroprevalence of 5.3% in individuals aged 51 to 70 years old.

Conclusions

Compared with other European countries, HEV seroprevalence among blood donors in southwest Switzerland is low. The low seroprevalence may be explained by the sensitivity of commercial tests used and/or the strict regulation of animal and meat imports. Data regarding HEV prevalence in Swiss livestock are lacking and merit exploration.  相似文献   

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