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31.
Anand Uttpal Dey Satarupa Bontempi Elza Ducoli Serena Vethaak A. Dick Dey Abhijit Federici Stefania 《Environmental Chemistry Letters》2023,21(3):1787-1810
Environmental Chemistry Letters - Microplastics pollution is major threat to ecosystems and is impacting abiotic and biotic components. Microplastics are diverse and highly complex... 相似文献
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Tiziana Romagnoli Giorgio Bavestrello Emellina M. Cucchiari Mario De Stefano Cristina G. Di Camillo Chiara Pennesi Stefania Puce Cecilia Totti 《Marine Biology》2007,151(2):537-552
The microalgal community associated with Eudendrium racemosum, a marine hydroid widely distributed in the Mediterranean Sea, was studied during an annual cycle, at monthly frequency,
in a coastal station of the Ligurian Sea. Microalgae were represented mainly by diatoms, which exhibited higher abundance
and biomass values between autumn and spring (max 46,752 cells mm−2 and 1.94 μg C mm−2, respectively), while during summer a significant decrease was observed (min 917 cells mm−2 and 0.013 μg C mm−2). High levels of abundance of filamentous cyanobacteria were observed in summer. Spatial distribution of epibiontic microalgae
showed a markedly increasing gradient from the basal to the apical part of hydroid colonies. Considering the growth forms
of diatom communities, motile diatoms (mainly small naviculoid taxa) were the most abundant in all the periods. Adnate (Amphora and Cocconeis spp.) were distributed mainly in the basal and central part of hydroid colonies and showed two peaks (autumn and summer).
Erect forms (mainly Tabularia tabulata, Licmophora spp., Cyclophora tenuis) were mainly distributed in the apical part of the colonies and showed their maximum densities in spring–summer. Tube-dwelling
(Berkeleya rutilans, Parlibellus sp.) were observed at low densities throughout the study period, without any significant temporal or spatial variability.
Comparing the microalgal communities on marine hydroid to those grown on mimic substrata placed in the sampling station during
summer, significantly higher values of abundance were observed in the hydroid, suggesting that microalgae may benefit from
the polyp catabolites. This fact was particularly evident for the adnate diatoms, whose temporal trend paralleled the cycle
of hydroid host. 相似文献
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The hypothesis that sexual ornaments are honest signals of quality because their expression is dependent on hormones with
immune-depressive effects has received ambiguous support. The hypothesis might be correct for those signals that are carotenoid-dependent
because the required carotenoid deposition in the signal, stimulated by testosterone, might lower the carotenoid-dependent
immune defence of the organism. Two pathways underlying this androgen-dependent honest signaling have been suggested. Firstly,
androgens that are needed for ornament expression may suppress immune defence, a cost that only high-quality animals can afford.
Alternatively, immune activation may downregulate the production of androgens in low-quality individuals. Which of these alternatives
is correct, and to what extent these effects are mediated by the different metabolites of androgens, remain open questions.
To provide answers to these questions, we manipulated the levels of testosterone (T), 5α-dihydrotestosterone (DHT), and 17-β-estradiol
(E2) in diamond doves Geopelia cuneata, a species in which both sexes exhibit a carotenoid-dependent, androgen-regulated red–orange periorbital ring of bare skin.
On the first day of the experiment (day 0), we inserted steroid-releasing implants into groups of birds and on day 14, we
subjected half of the birds to an immunological challenge by immunizing them with sheep red blood cells (SRBC). In females,
but not in males, androgen but not estradiol treatments reduced antibody production to SRBC. In addition, the immunological
challenge reduced redness and size of the trait as well as androgens levels in both sexes and in all treatments. This indicates
that an immunological challenge can lower circulating T at the cost of the trait expression. These findings are in accordance
with both pathways postulated in the immunocompetence-handicap hypothesis, but do not entirely support the idea that the immunosuppressive
effect of androgens yields honest signaling since both T and DHT were not immunosuppressive in males, for which sexual signaling
is supposed to be especially important. 相似文献
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Rare earth elements as critical raw materials: Focus on international markets and future strategies 总被引:2,自引:0,他引:2
Supply of some critical raw materials by European industry is becoming more and more difficult. After the case of natural textile fibres, in particular cotton, and timber, over the last few years the problem of rare earths (REs) availability has also risen. The 97% of the global supply of rare earth metals (REMs) is produced by China, that has recently done copious cuts of its exports, apparently in order to protect its environment. This fact has greatly increased the REs prices, causing tension and uncertainty among the world hi-tech markets. Many of these materials, in fact, have very few effective substitutes and low recycling rates too. In addition, their natural reserves of rare earths are concentrated in a small number of countries (China, Brazil, US, Russia, Democratic Republic of Congo). REMs are a group of 17 elements particularly used in many new electronic and advanced components: such as fuel cells, mobile phones, displays, hi-capacity batteries, permanent magnets for wind power generation, green energy devices, etc. Many analysts foresee much more requests in the next decades. 相似文献
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Squadrone Stefania Pederiva Sabina Bezzo Tabata Sartor Rocco Mussat Battuello Marco Nurra Nicola Griglione Alessandra Brizio Paola Abete Maria Cesarina 《Environmental science and pollution research international》2022,29(20):29529-29534
Environmental Science and Pollution Research - Microplastics are contaminants of great concern all over the world. Microplastics constitute pollutants themselves; moreover, other contaminants such... 相似文献
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Giuliani S Romano S Turetta C Cu NH Bellucci LG Capodaglio G Mugnai C Nhon DH Frignani M 《Journal of environmental monitoring : JEM》2011,13(5):1383-1392
Trace element concentrations have been measured in soil and sediment samples taken from the Thua Thien Hue (TT-H) Province and the Tam Giang-Cau Hai (TG-CH) Lagoon in 2002 and 2004. Results show that the lagoon is only slightly contaminated by elements such as Ag, Cd, Cr, Cu, Ni, Pb and Zn, whereas As, probably naturally enriched in this Asian region, reaches values above the lowest internationally accepted sediment quality guidelines. Concentrations in soils are ascribable to natural sources and distributions in the TG-CH Lagoon are mainly influenced by river inputs, with Ag and Cd undergoing estuarine desorption processes. However, concentration-depth profiles of most trace elements in sediments show a recent increasing trend that might be linked to the economic development of the area. The comparison of porosity and (210)Pb depth profiles (confirmed also by Cd and As) from repeated samplings of the same core locations in the TG-CH Lagoon seems to account for a loss of 5-10 cm of surficial sediment that took place during the time interval between the two samplings. It is hypothesized that extreme meteorological events (e.g. a major typhoon that hit the area in November 2003) could be responsible for such sediment displacement. 相似文献
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