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1.
Ilan Levy Yizhak Mahrer Uri Dayan 《Atmospheric environment (Oxford, England : 1994)》2009,43(12):1991-1999
This study examines the spatial distribution of potential recirculation over the East Mediterranean Sea, and the combined effect of synoptic and meso-scale recirculations on plume dispersion in the region. For this purpose, three case studies are performed by the RAMS–HYPACT modeling system, each for a different synoptic scale flow pattern. Both a quantitative measure of the recirculation potential at each grid cell and particle dispersion are calculated. Although the recirculation index is an Eulerian quantity for the wind field and plume dispersion is a manifestation of the Lagrangian behavior of the wind, good correlation is found between the two.Several locations are identified as having high recirculation potential, including southern Cyprus, the coasts of Israel and Lebanon, the eastern slopes of the Judean Mountains and the Haifa Bay in particular. In the latter location, high recirculation potential could be explained by strong interaction between the land–sea surfaces, curvature of the bay and proximity of the Carmel ridge. It is shown that the synoptic and meso-scale recirculations may, under certain conditions, act together and at the same time in determining particle distribution. Under weak synoptic scale flows, particles are recirculated over the entire East Mediterranean Sea basin, returning onshore after a period of 2–3 days to join freshly emitted particles. At the same time, near-shore land–sea breeze effects cause particles to recirculate on smaller time scales of less then one day, sometimes passing as much as three times over the same airshed. A single elevated emission source is shown to have the potential to impair air quality at a coastal strip as long as 100–200 km upon returning onshore. 相似文献
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The benefits of indigenous knowledge within disaster risk reduction are gradually being acknowledged and identified. However, despite this acknowledgement there continues to be a gap in reaching the right people with the correct strategies for disaster risk reduction.This paper identifies the need for a specific framework identifying how indigenous and western knowledge may be combined to mitigate against the intrinsic effects of environmental processes and therefore reduce the vulnerability of rural indigenous communities in small island developing states (SIDS) to environmental hazards. This involves a review of the impacts of environmental processes and their intrinsic effects upon rural indigenous communities in SIDS and how indigenous knowledge has contributed to their coping capacity. The paper concludes that the vulnerability of indigenous communities in SIDS to environmental hazards can only be addressed through the utilisation of both indigenous and Western knowledge in a culturally compatible and sustainable manner. 相似文献
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Cyanobacterial symbionts in the sponge Diacarnus erythraenus from the Red Sea were identified in both adult sponges and their larvae by 16S rDNA sequencing. A single cyanobacterial type was found in all samples. This cyanobacterial type is closely related to other sponge cyanobacterial symbionts. The cyanobacterial rDNA, together with the morphological analysis by electron and fluorescence microscopy, provided evidence for vertical transmission of the symbionts in this sponge. In addition, we show phenotypic plasticity of the symbionts inside the sponge, probably as a result of variability in light availability inside the sponge tissue. Finally, the reproduction of Diacarnus erythraenus is also described.Matan Oren, Laura Steindler have contributed equally to the work. 相似文献
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Cladopsammia gracilis (Dendrophylliidae), an ahermatypic coral inhabits the northern Red Sea. Two color morphs (pink and orange) are found aggregated
in caves devoid of hermatypic corals, associated with crustose coralline algae (CCA). Sequencing the rDNA ITS region revealed
a separate clustering of members of each color morph. Both morphs grow in shallow waters, with orange corals limited to the
upper 4 m, while some pink coral aggregates thrive deeper than 30 m. Planulae were released between June and December. Pink
planulae treated with antibiotics and exposed at different intervals to CCA, were competent and metamorphosed even 110 days
after release. Maximal competency period for orange planulae was 70 days. All planulae were enhanced to metamorphose in presence
of CCA. The mean age at metamorphosis of pink and orange planulae treated with CCA differed significantly. Most orange planulae
settled directly on the CCA while most pink planulae settled on the wall of the experiment vial. The morphs differed significantly
in the calyx cross-section area of primary polyps. Despite being considered a single species according to skeletal based taxonomy,
the significant ecological and molecular differences between pink and orange C. gracilis specimens suggest that they may belong to separate species. 相似文献
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A sensitive experimental protocol using cloned corals (hereafter microcolonies) of the branching scleractinian coral Stylophora pistillata and 45Ca has been developed to enable reproducible measurements of physiological and biochemical mechanisms involved in calcium transport and compartmentalization during coral calcification. Cloned S. pistillata microcolonies were propagated in the laboratory from small fragments of parent colonies collected in 1990 in the Gulf of Aqaba, Jordan. Cloned microcolonies have several intrinsic properties that help to reduce unwanted biological variability: (1) same genotype; (2) similar sizes and shapes; and (3) absence of macroscopic boring organisms. Errors specifically associated with long-standing problems to do with isotopic exchange were further reduced by producing microcolonies with no skeletal surfaces exposed to the radioisotope-labelled incubation medium. The value of the technique resides principally in its superior ability to elucidate transportation pathways and processes and not in its ability to quantitatively estimate calcium deposition by corals in nature. We describe here a rapidly exchangeable calcium pool in which up to 90% of the radioactive label taken up during incubations is located. This pool (72.9±1.4 nmol Ca mg-1 protein) is presumably located within the coelenteric cavity as suggested by the following: (1) it has 4-min half-time saturation kinetics; (2) the accumulation of calcium is linearly correlated with the calcium concentration of sea-water; and (3) its insensitivity to metabolic and ion transport inhibitors indicate that membranes do not isolate this compartment. Washout of this large extracellular pool greatly improved estimates of calcium deposition as evidenced by 10 to 40% reduction in coefficients of variation when compared with previous 45Ca2+ methods described in the literature. Comparisons of calcification measurements simultaneously carried out using the alkalinity anomaly technique and the 45Ca protocol described here show that the correlation coefficient of both techniques is close to 1. Unlike previous reports, our 45Ca2+-derived measurements are slightly lower than those computed from the alkalinity depletion technique. 相似文献
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The fetal inflammatory response syndrome (FIRS) describes a state of extensive fetal multi organ involvement during chorioamnionitis, and is associated with grave implications on perinatal outcome. The syndrome has been linked to the preterm parturition syndrome and is associated with inflammation/infection processes in most of the fetal organs. The fetal thymus, a major organ in the developing immune system involutes during severe neonatal disease and has been shown to be smaller in fetuses with FIRS. Various methods for imaging of the fetal thymus and measurement are described. Currently the only method to diagnose FIRS prenatally is through amniocentesis. We suggest that women who are admitted with preterm labor with intact membranes and those with PPROM should have a detailed sonographic examination of the fetal thymus as a surrogate marker of fetal involvement in intrauterine infection/inflammation processes. © 2015 John Wiley & Sons, Ltd. 相似文献
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Earthquakes are insured in high-risk high-income countries only if the public sector is involved. Prototypical examples are the insurance schemes in California (United States), Japan, and New Zealand, but each is structured differently. This paper examines these variations using a concrete case study: the sequence of earthquakes in Christchurch, New Zealand, in 2010–11—the most heavily insured seismic event in history. It assesses what would have been the outcome had the Christchurch insurance system been different, focusing on the California Earthquake Authority (CEA) programme and Japan Earthquake Reinsurance (JER). Overall, the aggregate cost of the earthquake to the New Zealand public insurer (Earthquake Commission) was USD 6.2 billion. If a similar-sized disaster had occurred in Japan and California, homeowners would have received around USD 1.6 billion and USD 0.7 billion, respectively. This paper describes the distributive and spatial patterns of these scenarios and discusses some key policy questions that emerge from this comparison. 相似文献
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The developmental changes of the fetal central nervous system (CNS) during the second and third trimesters, specifically the brain, relate mostly to changes in size. However, other changes do occur in the fetal brain during the second and third trimester such as: the union of the cerebellar hemispheres, development of the corpus callosum (CC), and increasing complexity of the cerebral cortex. These changes follow a well-defined developmental timeline recognizable by sonography. The fetal neuroscan can be divided into a ‘basic scan’ which is performed transabdominally and a ‘targeted Exam or neurosonogram’ which uses a multiplanar approach, which preferably should be performed transvaginally. During the ‘basic scan’, several brain structures are imaged in addition to obtaining important biometric measurements. The ‘neurosonogram’ is a more extensive or detailed fetal study during which the emphasis is on the addition of coronal and sagittal planes. The easiest way to obtain these planes, if the fetus is in a cephalic presentation, is the transvaginal route. Three-dimensional (3D) sonography should, if possible, be performed transvaginally using the multiplanar approach. An added benefit of 3D sonography is the ability to display and render the volume in a variety of ways which may enhance the detection of pathology. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
10.
In situ measurements of photosynthetic irradiance responses of two Red Sea sponges growing under dim light conditions 总被引:6,自引:0,他引:6
Photosynthetic responses to irradiance by the photosymbionts of the two Red Sea sponges Theonella swinhoei (Gray) and Clionavastifica (Hancock) growing under dim light conditions were measured in situ (in September 1997) using a newly developed underwater
pulse amplitude modulated (PAM) fluorometer. Relative rates of photosynthetic electron transport (ETR) were calculated as
the effective quantum yield of photosystem II (Y ) multiplied with the photosynthetic photon flux (PPF). Photosynthesis versus irradiance (P-I ) curves, obtained within minutes, showed that individual specimens of both sponges, growing under very low light conditions,
feature lower light saturation points as well as lower maximal ETRs than individuals growing under higher light. Evaluations
of such curves using low irradiances of the actinic light source (20 to 130 μmol photons m−2 s−1) showed a general decrease in Y, with a shoulder from the lowest irradiance applied till 20 to 30 μmol photons m−2 s−1. Point measurements yielded ETRs close to what could be estimated from the P-I curves. These point measurements also revealed good correlations between the diurnally changing ambient irradiances (1 to
50 μmol photons m−2 s−1) and average ETR values for both species. Further analysis showed that although Y values varied considerably between the different point measurements, they did not decrease significantly with light under
these very low irradiances. Therefore, PPF rather than Y seems to determine the in situ diel photosynthetic performance at the low ambient irradiances experienced by these sponges.
Received: 22 November 1997 / Accepted: 8 April 1998 相似文献