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Variations and trends in the rain regime of Israel are analyzed for 1975–2010, when persistent global warming has been observed. Negative trend is observed over the majority of Israel, statistically significant only in the super-arid region. The decrease is significant over the majority of Israel only in the spring, reflecting a shortening of the rainy season, >3 days/decade. The dry spells are becoming longer, significantly in most of the stations. The factors affecting these variations, synoptic systems, large-scale oscillations and global temperature, were studied for extended period, 1953–2010. A simple multiple stepwise regression model applied for the inter-annual rainfall variations indicates that the occurrence of Cyprus lows is the dominant factor and the Mediterranean oscillation index, MOI2, is also a significant factor. In order to reduce the inter-annual noise and reveal inter-decadal variations, the time-series of the rainfall and its potential predictors were smoothed by 11-year window, showing an increase toward the 1990s, followed by a decrease, at a higher rate, onward. Correspondingly, the aridity lines propagated southward till the mid-1990s and then withdrew back, at a larger rate. The large-scale oscillations and the global temperature explain 83 % of the variance on the inter-decadal time-scale, half of it explained by the global temperature alone. The findings of this study support the expected poleward expansion of the Hadley cell due to global warming.  相似文献   
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Many coral reefs worldwide are rapidly declining, but efficient restoration techniques are not yet available. Here, we evaluate methodologies for reef restoration based on the “gardening concept”. A floating mid-water prototype nursery was placed at 6 m depth (14 m above sea-bottom) within the nutrient-enriched environment of a fish farm (Eilat, Red Sea). Ten colonies from five branching coral species provided 6,813 fragments (0.5–3 cm height). The fragments, each attached to a plastic pin, were inserted into plastic nets that were tied to a rope-net floating nursery. After 144 nursery days, only 13.1% of the fragments died and 21.2% were detached by mechanical forces. Small colonies ready for transplantation developed within 144–200 days. Ramets’ ecological volumes increased 13–46 folds and their heights by a factor of 3.5. After 306 days, the ecological volumes of the colonies increased 147–163 fold as compared to original volumes (revealing a daily growth rate constant of 1.67% during the first 5–10 months) and height values by a factor of six. Building and maintenance costs of the nursery were low. This nursery prototype demonstrates the feasibility of the coral “gardening concept” by fulfilling several important needs, namely, mass production of coral colonies at low costs, high survivorship, fast growth, short nursery phase and improved methodologies for handling farmed colonies.  相似文献   
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Pelagic dispersal of larvae in sessile marine invertebrates could in principle lead to a homogeneous gene pool over vast distances, yet there is increasing evidence of surprisingly high levels of genetic differentiation on small spatial scale. To evaluate whether larval dispersal is spatially limited and correlated with distance, we conducted a study on the widely distributed, viviparous reef coral Seriatopora hystrix from the Red Sea where we investigated ten populations separated between ~0.150 km and ~610 km. We addressed these questions with newly developed, highly variable microsatellite markers. We detected moderate genetic differentiation among populations based on both F ST and R ST (0.089 vs. 0.136, respectively) as well as considerable heterozygote deficits. Mantel tests revealed isolation by distance effects on a small geographic scale (≤20 km), indicating limited dispersal of larvae. Our data did not reveal any evidence against strictly sexual reproduction among the studied populations.  相似文献   
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We report on ambient atmospheric aerosols present at sea during the Atlantic–Mediterranean voyage of Oceanic II (The Scholar Ship) in spring 2008. A record was obtained of hourly PM10, PM2.5, and PM1 particle size fraction concentrations and 24-h filter samples for chemical analysis which allowed for comparison between levels of crustal particles, sea spray, total carbon, and secondary inorganic aerosols. On-board monitoring was continuous from the equatorial Atlantic to the Straits of Gibraltar, across the Mediterranean to Istanbul, and back via Lisbon to the English Channel. Initially clean air in the open Atlantic registered PM10 levels <10 μg m?3 but became progressively polluted by increasingly coarse PM as the ship approached land. Away from major port cities, the main sources of atmospheric contamination identified were dust intrusions from North Africa (NAF), smoke plumes from biomass burning in sub-Saharan Africa and Russia, industrial sulphate clouds and other regional pollution sources transported from Europe, sea spray during rough seas, and plumes emanating from islands. Under dry NAF intrusions PM10 daily mean levels averaged 40–60 μg m?3 (30–40 μg m?3 PM2.5; c. 20 μg m?3 PM1), peaking briefly to >120 μg m?3 (hourly mean) when the ship passed through curtains of higher dust concentrations amassed at the frontal edge of the dust cloud. PM1/PM10 ratios ranged from very low during desert dust intrusions (0.3–0.4) to very high during anthropogenic pollution plume events (0.8–1).  相似文献   
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Ground water pollution due to herbicide leaching has become a serious environmental problem. Imazaquin [2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)quinoline-3-carboxylic acid] is an herbicide used to control broadleaf weeds in legume crops. Imazaquin is negatively charged at the basic pH of calcareous soils and exhibits high leaching potential in soils. Our aim was to design formulation of imazaquin to reduce herbicide leaching. Imazaquin sorption on pillared clay (PC) and crystal violet (CV)-montmorillonite complexes was studied. The CV-montmorillonite complexes become positively charged with adsorption of CV above the cation exchange capacity (CEC) of montmorillonite, and thus can sorb imazaquin. The Langmuir equation provides a good fit to isotherms of imazaquin sorption on PC and CV-montmorillonite complexes, but for charged complexes an equation that combines electrostatics with specific binding was preferred. Maximal imazaquin sorption was 17.3 mmol kg-1 for PC and 22.2 mmol kg-1 for CV-montmorillonite complexes. The extents of imazaquin desorption into water were 21% for PC and 5% for CV-clay complexes. The presence of anions decreased imazaquin sorption on both sorbents in the sequence phosphate > acetate > sulfate. Reduction of imazaquin sorption by the anions and the extent of its desorption in electrolyte solutions were higher for PC than for CV-clay complexes. Leaching of imazaquin from CV-montmorillonite formulations through soil (Rhodoxeralf) columns was two times less than from PC formulations and four times less than that of technical imazaquin. The CV-montmorillonite complexes at a loading above the CEC appear to be suitable for preparation of organo-clay-imazaquin formulations that may reduce herbicide leaching significantly.  相似文献   
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The language of decision theory is used to model the perspectives of two parties in the management of an environmental hazard. These are (a) individuals whose homes are polluted by radon by-products which thereby pose an uncertain health hazard and (b) the public authorities concerned about those individuals' welfare. The analysis provides a way of anticipating ways in which the perceptions and decisions of these parties are intertwined, as well as how they can come into conflict. It also suggests ways in which these difficulties might be ameliorated by altering the respective decision problems. The heuristic value of modeling decision problems in other contexts is discussed, with brief consideration of the substantive issues arising with acid rain and seatbelt usage.  相似文献   
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Prenatal real-time ultrasonographic diagnosis of exophthalmus is presented. Diagnosis was made at the 35th week of gestation in a fetus of a patient affected with Crouzon syndrome (craniofacial dysotosis). Recognition of exophthalmus as a part of Crouzon syndrome and the easy visualization of the eye balls and palpebrae in the third trimester made the diagnosis possible.  相似文献   
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