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111.
Paradelo R Villada A Devesa-Rey R Moldes AB Domínguez M Patiño J Barral MT 《Journal of environmental monitoring : JEM》2011,13(1):201-211
Trace element contamination is one of the main problems linked to the quality of compost, especially when it is produced from urban wastes, which can lead to high levels of some potentially toxic elements such as Cu, Pb or Zn. In this work, the distribution and bioavailability of five elements (Cu, Zn, Pb, Cr and Ni) were studied in five Spanish composts obtained from different feedstocks (municipal solid waste, garden trimmings, sewage sludge and mixed manure). The five composts showed high total concentrations of these elements, which in some cases limited their commercialization due to legal imperatives. First, a physical fractionation of the composts was performed, and the five elements were determined in each size fraction. Their availability was assessed by several methods of extraction (water, CaCl(2)-DTPA, the PBET extract, the TCLP extract, and sodium pyrophosphate), and their chemical distribution was assessed using the BCR sequential extraction procedure. The results showed that the finer fractions were enriched with the elements studied, and that Cu, Pb and Zn were the most potentially problematic ones, due to both their high total concentrations and availability. The partition into the BCR fractions was different for each element, but the differences between composts were scarce. Pb was evenly distributed among the four fractions defined in the BCR (soluble, oxidizable, reducible and residual); Cu was mainly found in the oxidizable fraction, linked to organic matter, and Zn was mainly associated to the reducible fraction (iron oxides), while Ni and Cr were mainly present almost exclusively in the residual fraction. It was not possible to establish a univocal relation between trace elements availability and their BCR fractionation. Given the differences existing for the availability and distribution of these elements, which not always were related to their total concentrations, we think that legal limits should consider availability, in order to achieve a more realistic assessment of the risks linked to compost use. 相似文献
112.
Ahmed A. Nassr Kamran Hessami Elena D’Alberti Antonella Giancotti Nazlisadat Meshinchiasl Mark I. Evans Daniele Di Mascio Alireza A. Shamshirsaz 《黑龙江环境通报》2023,43(11):1425-1432
To evaluate obstetrical outcomes for women having late amniocentesis (on or after 24 weeks). Electronic databases were searched from inception to January 1st, 2023. The obstetrical outcomes evaluated were gestational age at delivery, preterm birth (PTB) < 37 weeks, PTB within 1 week from amniocentesis, premature prelabor rupture of membranes (pPROM), chorionamnionitis, placental abruption, intrauterine fetal demise (IUFD) and termination of pregnancy (TOP). The incidence of PTB <37 weeks was 4.85% (95% CI 3.48–6.56), while the incidence of PTB within 1 week was 1.42% (95% CI 0.66–2.45). The rate of pPROM was 2.85% (95% CI 1.21–3.32). The incidence of placental abruption was 0.91% (95% CI 0.16–2.25), while the rate of IUFD was 3.66% (95% CI 0.00–14.04). The rate of women who underwent TOP was 6.37% (95%CI 1.05–15.72). When comparing amniocentesis performed before or after 32 weeks, the incidence of PTB within 1 week was 1.48% (95% CI 0.42–3.19) and 2.38% (95% CI 0.40–5.95). Amniocentesis performed late after 24 weeks of gestation is an acceptable option for patients needing prenatal diagnosis in later gestation. 相似文献
113.
Masting mediated by summer drought reduces acorn predation in Mediterranean oak forests 总被引:1,自引:0,他引:1
Temporally variable production of seed crops by perennial plants (masting) has been hypothesized to be a valuable mechanism in the reduction of seed predation by satiating and starving seed consumers. To achieve these benefits, coexisting species subjected to the same predator would benefit from a similar pattern of seeding fluctuation over time that could lead to a reduction in predation at the within-species level. We tested for the existence of an environmental factor enforcing synchrony in acorn production in two sympatric Mediterranean oaks (Quercus ilex and Q. humilis) and the consequences on within-species and between-species acorn predation, by monitoring 15 mixed forests (450 trees) over seven years. Acorn production in Q. ilex and Q. humilis was highly variable among years, with high population variability (CVp) values. The two species exhibited a very different pattern across years in their initial acorn crop size (sum of aborted, depredated, and sound acorns). Nevertheless, interannual differences in summer water stress modified the likelihood of abortion during acorn ripening and enforced within- and, particularly, between-species synchrony and population variability in acorn production. The increase in CVp from initial to mature acorn crop (after summer) accounted for 33% in Q. ilex, 59% in Q. humilis, and 60% in the two species together. Mean yearly acorn pre-dispersal predation by invertebrates was considerably higher in Q. humilis than in Q. ilex. Satiation and starvation of predators was recorded for the two oaks, and this effect was increased by the year-to-year variability in the size of the acorn crop of the two species combined. Moreover, at a longer time scale (over seven years), we observed a significant reduction in the mean proportion of acorns depredated for each oak and the variability in both species' acorn production combined. Therefore, our results demonstrate that similar patterns of seeding fluctuation over time in coexisting species mediated by an environmental cue (summer drought) may contribute to the reduction of the impact of seed predation at a within-species level. Future research should be aimed at addressing whether this process could be a factor assisting in the coexistence of Q. ilex and Q. humilis. 相似文献
114.
There is growing evidence that the sex ratios of wild vertebrate populations are determined by mechanisms that are directly
influenced by environmental characteristics. The Trivers–Willard (TWH) and extrinsic modification (EMH) hypotheses postulate
differing determinants of mammalian offspring sex ratios. TWH states that mothers allocate resources according to their current
condition and sex-specific offspring costs. EMH states that environmental forces that affect maternal condition determine
offspring sex ratios, independently of maternal tactics of sex-biased allocation. We statistically assessed support for each
of these hypotheses using long-term life histories of the allied rock-wallaby, Petrogale assimilis; a continuously breeding, polygynous, weakly dimorphic marsupial. We showed that birth sex ratios were equal and independent
of maternal and environmental conditions. However, secondary sex ratios were male-biased under good environmental conditions
and for high quality mothers or mothers in good condition. Sex differences in offspring survival contributed to these biases:
(1) environmental conditions strongly influenced survival to pouch emergence (in support of EMH) and (2) maternal quality
affected survival to the end of maternal care (in support of TWH). Environmental effects on survival were more important than
maternal factors over the entire period of maternal care and contributed most to male-biased sex ratios at pouch emergence.
In contrast, maternal mass was the best predictor of sex ratios at the end of maternal care—the life history stage where offspring
body mass differed between the sexes. 相似文献
115.
Anna Gagliardo Maria Savini Angelo De Santis Giacomo Dell’Omo Paolo Ioalè 《Behavioral ecology and sociobiology》2009,64(2):289-296
Some authors have proposed that homing pigeons are able to correct the error in orientation following a phase-shift treatment
by using the magnetic compass reference. They reported that clock-shifted pigeons bearing magnets display a greater deflection
compared to magnetically unmanipulated clock-shifted birds. However, this hypothesis tested by recording pigeons’ vanishing
bearings has led to contradictory results. The present study reports pigeons’ tracks recorded with a GPS and shows that clock-shifted
pigeons bearing magnets displayed a greater deviation through the whole route compared to the magnetically unmanipulated shifted
pigeons. Moreover, the analysis of the tracks shows that the birds belonging to both experimental groups stop in coincidence
with their subjective night. When re-starting their journey, the birds corrected the clock-shift induced error in orientation,
but the magnetically manipulated pigeons were less efficient in doing so. Our results are consistent with the hypothesis that
homing pigeons released from unfamiliar location re-orient after clock shift by using the magnetic compass. 相似文献
116.
Wafa Feki-Sahnoun Asma Hamza Mabrouka Mahfoudi Ahmed Rebai Malika Bel Hassen 《Environmental science and pollution research international》2014,21(19):11481-11499
Microphytoplankton data along the southern Tunisian coasts have been monitored weekly since 1995. This study used the data collected during the period 2000–2007 to determine the temporal variability patterns and to characterize the geographical structures of microphytoplankton populations. The methodological approach consisted in isolating the temporal variability common to all sampled sites and in analyzing the “residual” site-specific component. Multivariate ordination methods were used to determine the seasonal and interannual variability. The temporal pattern shared by all sites was highlighted and the seasonal cycle of the most frequent phytoplankton communities contrasted the diatoms winter-spring species to the dinoflagellates summer-fall species. Multitable comparison allowed the identification of three areas exhibiting similar phytoplankton population variability. The results, despite the coastal location of sampling sites, indicated that hydrodynamic and geomorphologic properties of the different areas as well as anthropogenic activities play a key role in the structure of the phytoplankton communities. 相似文献
117.
The officer of the deck (OOD) of a US Navy ship is in charge of the safe and proper operation of the ship, and accountable to the commanding officer for every event that occurs during his or her OOD watch. This paper discusses the development of a prototype behavioral marker system to evaluate, and provide feedback on, the nontechnical (cognitive, social, and personal resource) skills of OODs.An initial set of 17 categories of nontechnical skills were identified from a literature review. A focus group with four qualified OODs used the skills identified from the literature review to develop an initial taxonomy of five categories, each with two or three corresponding behavioral elements. This taxonomy was then used to classify 149 statements concerned with the nontechnical skills of OODs collected from 16 critical incident interviews. After three iterations of adaptations to the taxonomy, two independent raters were able to reach acceptable levels of reliability in using the taxonomy to classify the statements. Although further development work is required, it is suggested that the prototype behavioral marker system has implications for improving safety and performance on military and civilian ships. 相似文献
118.
Axel Michaelowa John O’brien 《Mitigation and Adaptation Strategies for Global Change》2006,11(3):711-722
A United Nations Framework Convention on Climate Change (UNFCCC) Joint Implementation (JI) host country has to make sure that
JI projects are additional to avoid extra costs to generate the reductions necessary to cover the deduction of Emission Reduction
Units (ERUs) from the country’s Kyoto Protocol emissions budget. A tender of ERUs by the government allows to generate additional
reductions beyond the ERUs issued if it thoroughly checks project additionality. The government of New Zealand is running
a tender for JI projects under the title “Projects to Reduce Emissions” since 2003. In two rounds, 10 million ERUs have been
awarded and several projects have already entered into contracts with European buyers. The ratio of ERUs awarded to reductions
achieved was 0.8 in the second tender. However it remains to be seen whether the additionality test of this tender is sufficient
to exclude clearly non-additional projects. 相似文献
119.
A. A. Nikol’skii 《Russian Journal of Ecology》2007,38(4):271-276
With consideration of the data on soil temperature within the range and over the burrow depth of the greater mole rat Spalax microphthalmus Güld. (1770) published in the Handbook on the Climate of the Soviet Union, it has been shown that the fundamental temperature niche of this species is relatively narrow. The seasonal activity of the greater mole rat in the vertical plane of the burrow depends on the vertical distribution of soil temperature. 相似文献
120.
Chemical pollution: Transfer of chemical elements to the aboverground phytomass of herbaceous plants
Changes in the species composition and a decrease in species diversity and total plant biomass along the gradient of soil pollution with heavy metals have been shown. Data on the concentrations of chemical elements (Zn, Cu, Cd, Pb, Co, Ni, Mn, Cr, and Fe) in the aboveground organs of herbaceous plants and the biomass of each species make it possible to estimate the role of higher producers in the incorporation of chemical elements into biogenic cycles in background zones and under conditions of chemical pollution. Plants of the composite family (Asteraceae) play the main role in accumulation of chemical elements. The results obtained indicate that natural ecosystems have mechanisms limiting excessive accumulation of chemical elements into the aboveground plant biomass. 相似文献