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101.
Floods have been the most deadlynatural disasters in Portugal during the lastcentury, followed by earthquakes. The typeof flood known as a `progressive flood'mainly affects the larger basins, such asthat of the Tagus River, and results in alarge inundated area. These floods arecaused by heavy rains associated with awesterly zonal circulation that may persistfor weeks. The system of dams within thebasin reduces the frequency of flooding,but cannot `tame' the river. The dam systemhas even contributed to an increase in thepeak flow, as in the 1979 flood.Nevertheless, these floods are not a dangerfor the human population. In contrast, flashfloods are more dangerous and deadlier thanprogressive floods, as demonstrated in 1967and 1997. They affect the small drainagebasins and are caused by heavy andconcentrated rainfall, created byconvective depressions (active cold poolsor depressions caused by the interactionbetween polar and tropical air masses),active in the south of the country, in theLisbon region, Alentejo and the Algarve.Deforestation, soil impermeability, chaoticurbanization, building on floodplains, theblockage of small creeks or theircanalisation, and the building of walls andtransverse embankments along the smallcreeks all contribute to the aggravation ofthis kind of flood.  相似文献   
102.
Field tests were made for the control of an olive insect pest, the olive bark beetle, Phloeotribus scarabaeoides (Col: Scolytidae), using the pyrethroid insecticide deltamethrin (D) and this insecticide combined with ethylene (D+E), an attractant of the olive bark beetle. The tests were run in olive orchards in the provinces of Granada and Jaén (Andalusia, southern Spain), treating several olive rows so as to create a barrier effect to control the pest attack. The main objective was to evaluate the arthropod fauna affected by these treatments. The different taxa captured have been separated in three different trophic groups: parasitoids, predators and phytophagous. A knock-down effect was found during the first dates in all the functional groups in all cases. The results showed the following trend in arthropod abundance: D+E>D>C. This trend was significant (p<0.05) for predators and phytophagous insects in both zones. The parasitoids of Prays oleae (Lep.: Plutellidae), a major olive pest, were most affected by the treatments, together with several groups of predators such as ants, cantharids, coccinellids and mirids. Data from the captures show the need to determine the optimum time for insecticide application in order to minimise its effect on beneficial insect populations.  相似文献   
103.
Feasibility of three different extraction methods for the simultaneous determination of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in butter is discussed. The method based on liquid-liquid extraction with water of the non fatty solids from butter dissolved in hexane was found to be the most efficient for the determination of the lipid content and the levels of the investigated pollutants. This method was used to evaluate the background levels of PCBs, PCDDs and PCDFs in butters commercially available in Spain. Broad ranges of PCB, specifically, PCDD and PCDF concentrations were found in the different brands analysed. Levels, profiles and patterns of these pollutants in butter were compared with those previously reported for different Spanish dairy products. The toxic tetra-equivalents of 2,3,7,8-TCDD (1-TEQ) averages for PCDDs and PCDFs in the 21 butter samples analysed were 0.41 and 0.70 pg/g fat basis, respectively. These values were similar or lower than those cited in the literature for other countries.  相似文献   
104.
The insect immune system faces various challenges; particularly in social bees, caste system and age polyethism expose individuals to numerous environmental and working conditions. However, little is known about how cellular defenses in social bees may be organized to respond to a variety of immune challenges. Here, we describe the morphological features and the total and differential counts of hemocytes in different female classes (newly emerged workers, nurses, foragers, and virgin queens) of the eusocial stingless bee Melipona quadrifasciata. Granulocytes and prohemocytes were, respectively, the most and the least abundant cells among all classes of females. Furthermore, there were more prohemocytes in virgin queens than in foragers. The total number of hemocytes was smaller in foragers, whereas the largest number was observed in nurse workers. This reduced amount of hemocytes in foragers might allow energy savings to perform colony activities such as foraging and defense. Foragers also had the biggest hemocytes (either prohemocytes, granulocytes, or plasmatocytes) in comparison to the other classes of females, which might have arisen as a compensation for the reduction in number of these cells during aging. These results suggest that profiles of hemocytes of M. quadrifasciata vary according to the caste and age of this eusocial bee.  相似文献   
105.
Results of glyphosate (GPS) adsorption on three soils of different characteristics show that the interaction of this pesticide with the soils was not related to their CEC and clay minerals content, but to the content of iron and aluminum amorphous oxides and organic matter. The presence of Cu in treatment solutions enhanced GPS adsorption, due to several reasons: GPS coordinates strongly to Cu, and Cu GPS complexes formed seem to have higher ability to be adsorbed on the soil than free GPS; GPS adsorption can take place on sites where Cu was previously adsorbed, acting as a bridge between the soil and GPS; when Cu was present the solution pH decreased, and GPS adsorption increased, since lower pHs lead to the formation of GPS species with lower negative charge, which are adsorbed more easily on the negatively charged soil surfaces.  相似文献   
106.
There are important linkages between the health of humans and theenvironment, restoration of degraded lands, and long-term stewardship of public lands, yet most environmental indicators deal only with assessing the physical and biological aspects ofecosystems. In this article, we examine the ratings of perceptionsof several environmental problems for their utility as indicatorsof environmental quality, and examine perceptions of future land use by people interviewed in Santa Fe, New Mexico, near the Department of Energy's (DOE) Los Alamos National Laboratory (LANL). Overall, people with lower incomes rated environmental problems as more severe than others, were more willing to spend federal funds to solve them, and were consistent in their ratingsof severity of environmental problems and their willingness to spend federal funds. Cleaning up LANL and other Department of Energy sites, received the highest rating for expenditure of federal funds. The highest rated future uses for DOE sites were for recreation and for National Environmental Research Parks. People with less education generally gave higher ratings to mostfuture land uses for DOE than did those with more education. However, those with higher education gave higher ratings to nuclear reprocessing, and nuclear material storage. Where there were differences, the people interviewed at Santa Fe rated all environmental problems (except pesticides) as more severe than did those previously interviewed in Albuquerque (located fartherfrom the LANL site), and they were more willing to spend federalfunds on these problems. Ratings for all future land uses did notdiffer between the Santa Fe and Albuquerque respondents. These perception-based indicators show general agreement among peopleliving close and farther away from LANL with respect to cleaningup LANL and the future land uses for the site. These indicators should be considered by regulators, site personnel, and policy makers in future management and land use decisions.  相似文献   
107.
Infestation by leeches on adult freshwater turtles Phrynops geoffroanus in two areas of the Uberabinha River, in Uberlandia, was investigated during the summer (January 2000). Fifty eight turtles were trapped: 26 (12 males, 14 females) in an agricultural area and 32 (16 males, 16 females) in an area with a more urban environment. The females present larger length and body mass (291.77+/-29.18 mm; 2233.30+/-511.40 g) than males (259.71+/-33.15 mm; 1488.68+/-529.35 g). Blood samples were drawn from the retrorbital sinus using heparinized micro-hematocrit capillary tubes, for microscopic and direct examination for intracellular parasites. Ectoparasitism by leeches, Placobdella bistriata, on young and adult animals was observed in the limb cavities of 28.1% of the urban area turtles. No leeches were found on the turtles in the agricultural area. Hemogregarine erythrocytic gametocytes were found in 15.4% of the agricultural area turtles, and in 37.5% of the urban area turtles. Concurrent parasitism by leeches and hemogregarines on the same individuals was seen on six turtles. Infections with microorganisms (bacteria and fungus) facilitated by the bites of leeches were not observed in another study on the same sample of infested turtles. However, 19% of the turtles collected in the agricultural area and 15% of the turtles from the urban area presented normocytic acute anemia. The occupation of the soil apparently interfered in the aquatic ecosystem favoring parasitism in the urban area.  相似文献   
108.
Environmental Science and Pollution Research - A simple, efficient, environmentally friendly, and inexpensive synthesis route was developed to obtain a magnetic nano-hybrid (GH) based on graphene...  相似文献   
109.
110.
There are several different approaches to evaluate regional environmental and sustainability performance, where regional indicators are an emerging issue. Academia could play an important role in many sustainable initiatives, giving credibility, scientific and technical support and contribute to increasing public participation. This paper intends to trace the Portuguese profile on regional Sustainable Development Indicators (SDI) initiatives and contribute to an understanding of the key factors related to the role of academia in those processes. A national survey was conducted to obtain data on SDI initiatives on a regional scale and the Portuguese profile was defined. Overall results show that SDI implementations are concluded in one region and are being implemented in three of the total of seven regions, despite a significant lack of institutional guidelines and policy guidance from national authorities. The particular approach conducted in the Algarve, the most southerly region of Portugal, was analysed. The indicators developed for this region are a practical example of how academia and regional public authorities can cooperate efficiently, involving multi-stakeholders, to obtain the desired outcomes.  相似文献   
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