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71.
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73.
Chafika Mazouni Géraldine Porcu-Buisson Nadine Girard R. Sakr Dominique Figarella-Ballanger Béatrice Guidicelli Pascal Bonnier Marc Gamerre 《黑龙江环境通报》2003,23(2):104-107
Fetal brain tumors are rare and teratoma is considered as the most common. Fetal MR Imaging is currently used to evaluate cases of ventricular dilatation. We report a case of cerebral immature teratoma detected by ultrasonography because of ventricular dilatation at 24 gestational weeks. MRI was the more accurate imaging method in depicting the tumor and its consequences on brain development as well as in taking a decision with regard to the management of pregnancy. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
74.
Summary. Lactating rabbit females emit volatile odour cues that trigger specialized motor actions leading to sucking. But the activity
of these cues may change with advancing lactation. Here, we tested this possibility in three experiments. In Exp. 1, we assessed
whether 2-day-old pups respond differently to the odour of milk from females in early (day 2) as compared to late (day 23)
lactation. In Exp. 2, a compound bearing pheromonal properties, the Mammary Pheromone (MP), was dosed in these milks to assess
whether its concentration is correlated with behavioural activity. In Exp. 3, the responsiveness to a constant level of MP
was compared in d2 versus d23-pups. Run on 240 pups, the assays showed that a) the milk activity declines between d2 and d23
of lactation; b) during this same period, the concentration of the MP decreases in milk; c) the MP itself becomes less active
to elicit oral grasping in pre-weaning pups than in newborns. These results indicate that the MP is active during the period
when pups are exclusively dependent on milk. The convergent changes in emission and reception of this pheromone may sequentially
warrant that pups are first attracted to the mammae, and then that they progressively disinvest the mother as they begin to
eat solid food and to be attracted by other conspecifics. 相似文献
75.
Partitioning the factors of spatial variation in regeneration density of shade-tolerant tree species
Understanding coexistence of highly shade-tolerant tree species is a longstanding challenge for forest ecologists. A conceptual model for the coexistence of sugar maple (Acer saccharum) and American beech (Fagus grandibfolia) has been proposed, based on a low-light survival/high-light growth trade-off, which interacts with soil fertility and small-scale spatiotemporal variation in the environment. In this study, we first tested whether the spatial distribution of seedlings and saplings can be predicted by the spatiotemporal variability of light availability and soil fertility, and second, the manner in which the process of environmental filtering changes with regeneration size. We evaluate the support for this hypothesis relative to the one for a neutral model, i.e., for seed rain density predicted from the distribution of adult trees. To do so, we performed intensive sampling over 86 quadrats (5 x 5 m) in a 0.24-ha plot in a mature maple-beech community in Quebec, Canada. Maple and beech abundance, soil characteristics, light availability, and growth history (used as a proxy for spatiotemporal variation in light availability) were finely measured to model variation in sapling composition across different size classes. Results indicate that the variables selected to model species distribution do effectively change with size, but not as predicted by the conceptual model. Our results show that variability in the environment is not sufficient to differentiate these species' distributions in space. Although species differ in their spatial distribution in the small size classes, they tend to correlate at the larger size class in which recruitment occurs. Overall, the results are not supportive of a model of coexistence based on small-scale variations in the environment. We propose that, at the scale of a local stand, the lack of fit of the model could result from the high similarity of species in the range of environmental conditions encountered, and we suggest that coexistence would be stable only at larger spatial scales at which variability in the environment is greater. 相似文献
76.
Dominique G. Roche Rose E. O'Dea Kecia A. Kerr Trina Rytwinski Richard Schuster Vivian M. Nguyen Nathan Young Joseph R. Bennett Steven J. Cooke 《Conservation biology》2022,36(3):e13835
The knowledge-action gap in conservation science and practice occurs when research outputs do not result in actions to protect or restore biodiversity. Among the diverse and complex reasons for this gap, three barriers are fundamental: knowledge is often unavailable to practitioners and challenging to interpret or difficult to use or both. Problems of availability, interpretability, and useability are solvable with open science practices. We considered the benefits and challenges of three open science practices for use by conservation scientists and practitioners. First, open access publishing makes the scientific literature available to all. Second, open materials (detailed methods, data, code, and software) increase the transparency and use of research findings. Third, open education resources allow conservation scientists and practitioners to acquire the skills needed to use research outputs. The long-term adoption of open science practices would help researchers and practitioners achieve conservation goals more quickly and efficiently and reduce inequities in information sharing. However, short-term costs for individual researchers (insufficient institutional incentives to engage in open science and knowledge mobilization) remain a challenge. We caution against a passive approach to sharing that simply involves making information available. We advocate a proactive stance toward transparency, communication, collaboration, and capacity building that involves seeking out and engaging with potential users to maximize the environmental and societal impact of conservation science. 相似文献
77.
Imane Abbas Ghidaa Badran Anthony Verdin Frédéric Ledoux Mohamed Roumié Dominique Courcot Guillaume Garçon 《Environmental Chemistry Letters》2018,16(2):439-475
Polycyclic aromatic hydrocarbons (PAHs) are worldwide pollutants produced mainly during incomplete combustion and pyrolysis of organic substances. PAH derivatives are components with hydrogen on the aromatic ring substituted by carbonyl-, nitro- and hydroxyl-functional groups (N-PAH, O-PAH or OH-PAH), or a group of heterocyclic PAHs containing one sulfur atom in place of a carbon atom in the aromatic ring. PAHs and their derivatives can be either introduced in the atmosphere directly in this form as primary pollutants, or formed by homogenous and heterogeneous oxidation reactions. During the last decades, interest on studying PAH derivatives has increased because derivatives may be more harmful than parent compounds. PAH derivatives have been detected in the atmospheric particulate matter in numerous cities worldwide. PAH derivatives enter living organisms by inhalation, oral ingestion and dermal contact. In vivo and in vitro experiments together with epidemiological studies have shown the toxic effects of PAH derivatives, notably for compounds present in airborne and diesel exhaust particles. Here we review the sources, the mechanisms of formation, the physicochemical properties, the analytical methods, and the toxicological effects of PAHs and their derivatives in airborne particulate matter. 相似文献
78.
Flament P Mattielli N Aimoz L Choël M Deboudt K de Jong J Rimetz-Planchon J Weis D 《Chemosphere》2008,73(11):1793-1798
A study on tropospheric aerosols involving Fe particles with an industrial origin is tackled here. Aerosols were collected at the largest exhausts of a major European steel metallurgy plant and around its near urban environment. A combination of bulk and individual particle analysis performed by SEM–EDX provides the chemical composition of Fe-bearing aerosols emitted within the factory process (hematite, magnetite and agglomerates of these oxides with sylvite (KCl), calcite (CaCO3) and graphite carbon). Fe isotopic compositions of those emissions fall within the range (0.08‰ < δ56Fe < +0.80‰) of enriched ores processed by the manufacturer (−0.16‰ < δ56Fe < +1.19‰). No significant evolution of Fe fractionation during steelworks processes is observed. At the industrial source, Fe is mainly present as oxide particles, to some extent in 3–4 μm aggregates. In the close urban area, 5 km away from the steel plant, individual particle analysis of collected aerosols presents, in addition to the industrial particle type, aluminosilicates and related natural particles (gypsum, quartz, calcite and reacted sea salt). The Fe isotopic composition (δ56Fe = 0.14 ± 0.11‰) measured in the close urban environment of the steel metallurgy plant appears coherent with an external mixing of industrial and continental Fe-containing tropospheric aerosols, as evidenced by individual particle chemical analysis. Our isotopic data provide a first estimation of an anthropogenic source term as part of the study of photochemically promoted dissolution processes and related Fe fractionations in tropospheric aerosols. 相似文献
79.
Jocelyne de Laveaucoupet François Audibert Françoise Guis Caroline Rambaud Bruno Suarez Claire Boithias-Guérot Dominique Musset 《黑龙江环境通报》2001,21(9):729-736
The aim of the present study was to demonstrate the usefulness of fetal magnetic resonance imaging (MRI) in ischemic brain injury. We report seven cases of fetal brain ischemia prenatally suspected on ultrasound (US) and confirmed by fetal MRI. Sonographic abnormalities included ventricular dilatation (n=3), microcephaly (n=1), twin pregnancy with in utero death of a twin and suspected cerebral lesion in the surviving co-twin (n=3). MRI was performed with a 1.0 T unit using half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequences between 28 and 35 weeks of gestation. US and MRI images were compared with pathologic findings or postnatal imaging. MRI diagnosed hydranencephaly (n=1), porencephaly (n=2), multicystic encephalomalacia (n=2), unilateral capsular ischemia (n=1), corpus callosum and cerebral atrophy (n=1). In comparison with US, visualization of fetal brain anomalies was superior with MRI. The present cases demonstrate that MRI is a valuable complementary means of investigation when a brain pathology is discovered or suspected during prenatal US. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
80.
Sampaolo Gianluca Lepore Dominique Spigarelli Francesca 《Environment, Development and Sustainability》2021,23(11):16803-16818
Environment, Development and Sustainability - Blue Economy (BE), as a novel approach fostering the sustainability of oceans and coastal areas for economic growth, is considered an enabler for... 相似文献