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101.
102.
Like its British prototype (Biological Monitoring Working Party score system), the Polish benthic invertebrate-based BMWP-PL index is commonly regarded as an indicator of river water quality. This interpretation of the index has been verified in a study of the gravel-bed Bia?a River. Benthic macroinvertebrates were sampled at 10 sites and compared in one channelized and one unmanaged cross-section per site. The resulting taxa richness and BMWP-PL index scores were compared with water quality and physical habitat characteristics in the cross-sections. Channelized and unmanaged cross-sections clearly differed in their physical habitat conditions, and water quality characteristics mostly varied in the downstream direction. Particular cross-sections hosted between 3 and 26 invertebrate taxa, with the respective BMWP-PL scores indicating the water in the surveyed cross-sections varied between high and poor quality. However, the BMWP-PL scores were unrelated to physicochemical characteristics of the river water, which consistently pointed to high water quality. Instead, the scores were significantly related to several physical habitat variables, with the number of low-flow channels in a cross-section explaining the largest proportion of the variance in the index values. The relationship of the scores with the complexity of flow pattern in the river and a lack of their dependence on physicochemical water characteristics show that the BMWP-PL index should not be regarded as an indicator of water quality but rather as an indicator of the ecological status of rivers, dependent both on their hydromorphological and water-quality characteristics.  相似文献   
103.
Seven Mannich base derivatives of polyether antibiotic Lasalocid acid (2a2g) were synthesized and screened for their antiproliferative activity against various human cancer cell lines. A novel chemoselective one-pot synthesis of these Mannich bases was developed. Compounds 2a2c and 2g with sterically smaller dialkylamine substituent, displayed potent antiproliferative activity (IC50: 3.2–7.3 μM), and demonstrated higher than twofold selectivity for specific type of cancer. The nature of Mannich base substituent on C-2 atom at the aromatic ring may be critical in the search for selectivity towards a particular cancer cell.  相似文献   
104.
105.
Monthly samples of about 40 separate plants of each species were collected from 1 to 3 m below lowest astronomical tide on Port Erin breakwater, Isle of Man, Irish Sea. In three species growing on rock, Plocamium cartilagineum, Cryptopleura ramosa and Callophyllis laciniata, about 90% of the plants were fertile in late summer but less than 10% in spring although some fertile plants were always present. Delesseria sanguinea and Odonthalia dentata, also epilithic, had a winter sporing season, Odonthalia extending into late spring, and all plants were sterile in summer. Three species growing epiphytically, Palmaria palmata, Membranoptera alata and Phycodrys rubens, reproduced maximally in the first half of the year at the time when the stipes of the host species, Laminaria hyperborea, grow fastest. Only Palmaria had a sterile season, late summer. The encrusting Cruoria pellita showed little seasonality. The first three species, which reproduce mainly when the sea temperature is above average, are in the northern part of their geographical range. The remaining species (apart from Cruoria) reproduce mainly at low temperatures and are in the southern half of their ranges. Male plants appear to be in a minority in all species, presumably because they were manifest for a shorter period than carposporic plants. They appeared first after sterile periods and were absent as sporing declined. Plocamium and to a lesser extent Cryptopleura show an extremely high preponderance of tetrasporophytes in the population. This is attributed to perennation and some factor disallowing the survival of most of the tetraspores.  相似文献   
106.
Samples of individual plants of Delesseria sanguinea and Odonthalia dentata were collected from shallow subtidal populations off the south end of the Isle of Man during the reproductive season. Reproductive bladelets were measured and their state of fertility noted. In Delesseria, male bladelets appeared in early September and achieved maximum size in mid October when bladelets of all sizes became fertile; the largest of these dehisced first and all were spent by mid December. Females appeared 3 weeks later; carpogonia were fertilized during October but carpospores were not released until about February when maximum bladelet length was reached. In about half the bladelets carpogonia remained unfertilized and did not grow further and only 40% of successful fertilizations resulted in carpospore release. Tetrasporangial bladelets did not appear until November and tetraspores were released in January and February while bladelets were still growing. Gametophytes and tetrasporophytes existed in about equal numbers. In Odonthalia, all three types of bladelet appeared in early November and fertilization took place in December, but later-developing carpogonia seemed to remain unfertilized in spite of a second wave of production of spermatangia, resulting in a low fertilization success of about 7%. Both carpospores and tetraspores dehisced from January to April. In this species the gametophytes formed about 58% of the population, a proportion expected from equal survival of number of spores per parent.  相似文献   
107.
108.
The adhesion of cells to solid supports is described as surface-dependent, being largely determined by the properties of the surface. In this study, ceramic surfaces modified using different organosilanes were tested for proadhesive properties using industrial brewery yeast strains in different physiological states. Eight brewing strains were tested: bottom-fermenting Saccharomyces pastorianus and top-fermenting Saccharomyces cerevisiae. To determine adhesion efficiency light microscopy, scanning electron microscopy and the fluorymetric method were used. Modification of chamotte carriers by 3-(3-anino-2-hydroxy-1-propoxy) propyldimethoxysilane and 3-(N, N-dimethyl-N-2-hydroxyethyl) ammonium propyldimethoxysilane groups increased their biomass load significantly.  相似文献   
109.
In contrast to common belief, recent studies have confirmed that intrusive growth of fusiform cambial initials has a significant role in the rearrangement of the initials, but does not contribute to the cambial circumference increment. We observed a rapid rearrangement of cambial initials on a long series of transverse sections of the vascular cambium and the wood of a 50-year-old pine (Pinus sylvestris L.) tree. A comparison of cell arrangement in consecutive sections, as well as a critical analysis of tangential reconstructions, has confirmed that changes in cell locations in a group of cells on the tangential surface caused no change in the total tangential width of the whole group. Models illustrating changes in locations of the initials have been proposed, assuming that intrusive growth, which makes the growing initials intrude between the neighbouring initials and their immediate derivatives, is localized on the longitudinal edges of cells. We infer that intrusive growth of the cambial initials in P. sylvestris is not involved in the cambial circumference increment, but plays a significant role in the rearrangement of the initials, probably allowing for a relaxation of shearing strains generated during radial growth. The relationship of intrusive growth with the elimination of initials has been discussed with reference to the frequency of anticlinal divisions. It has been proposed that the occurrence of anticlinal divisions in excess over the actual requirement for increase in the cambial circumference could be due to internal shearing strains.  相似文献   
110.

Purpose

In this two-part paper (Background and Initial Assumptions (part 1) and Results of Survey Research (part 2)), we present surveys whose main objective is to determine whether, and to what extent, the life cycle assessment (LCA) technique is used for the identification and assessment of environmental aspects in environmental management systems (EMS) and whether there are any differences in this respect between the companies and countries analysed.

Methods

The survey research was carried out using the computer assisted self-administered interviewing method among selected Polish, German and Swedish organisations which implement EMS in accordance with the requirements of ISO 14001 and/or the EMAS regulation.

Results

The organisations investigated, regardless of their country, are dominated by qualitative and semi-quantitative techniques of assessment and identification of environmental aspects. LCA was used sporadically, although some differences can be observed between the countries analysed.

Conclusions

The environmental managers accustomed to traditional qualitative and semi-quantitative solutions have not been given preparation to enable them to understand and adopt different approaches such as LCA. On the other hand, representatives of the organisations investigated declared that they were ready to accept an even longer timescale for the identification and assessment processes relating to environmental aspects, which represents a potential opportunity for LCA. The more precise understanding and definition of environmental problems that are precisely defined in LCA would represent a novelty for environmental managers. In practice, environmental problems are defined in a general sense and rather ambiguously, as this level of detail is sufficient in the context of qualitative and semi-quantitative techniques commonly used for the identification and assessment of environmental aspects.  相似文献   
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