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1.
New Forests - Spanish red cedar, Cedrela odorata L. (Meliaceae), is a valuable timber tree in tropical American forests. Existing demand for elite individuals endangers the conservation of...  相似文献   
2.
Environmental factors, such as global solar radiation, wind speed, air temperature, humidity, and CO2 concentration, were measured above and within the canopy of a tropical rainforest in Lambir Hills National Park, Sarawak, Malaysia. Few data concerning the environment of this forest have been reported. Intensive observations were carried out in 1998, 1999, and 2000 with the following results: (1) The fraction of global solar radiation reaching the upper layer of the canopy varied with global solar radiation above the canopy. Even though the global solar radiation above the canopy fluctuated, the fraction of that reaching the lower canopy and the ground was constantly approximately 5%. (2) The fraction of wind speed reaching each layer of the canopy increased with wind speed above the canopy. Little wind was usually present at the lower canopy. (3) The daytime air temperature at the canopy top was higher than that near the ground. The maximum difference between the air temperature at the canopy top and that at the ground was about 5°C, and the diurnal temperature ranges at the canopy top and those at the ground were about 8°C and about 5°C, respectively. The highest daytime water vapor pressure occurred within the canopy and particularly near the ground. Vertical gradients of water vapor pressure during the day were steep, probably because of high transpiration. (4) In the 1998 observation the minimum and the maximum CO2 concentrations were 360 ppm in the day and 450 ppm at night, while in the 2000 observation the minimum and the maximum CO2 concentrations were 350 ppm in the day and 540 ppm at night. The higher CO2 concentration in the daytime and the lower concentration at night observed during the 1998 observation period were probably due to reduced photosynthesis and soil respiration caused by exceptional dry conditions during the observation period.  相似文献   
3.
The Siberian moth, Dendrolimus sibiricus, Tschtv. is the most harmful defoliator of coniferous forests in North Asia. The pest has already spread over the Urals and continues moving westwards. Recently, it has been recommended for quarantine in member countries by European and Mediterranean Plant Protection Organization (EPPO). The performances of the pest on coniferous species planted in Europe were assessed on a range of potted trees corresponding to the spectrum of economically important conifers in the EU: European larch Larix decidua, Norway spruce Picea abies, Scots pine Pinus sylvestris, European black pine Pinus nigra, and the North American species: Douglas fir Pseudotsuga menziesii and grand fir Abies grandis. Larvae showed a potential to survive and complete the development on all these host tree species. Favorable hosts were grand fir, European larch, and Douglas fir that allowed higher survival, better larval development, and as a result, yielded heavier pupae and adult moths with higher longevity. Black pine was a poor host but, however, could still support larval and pupal development. Norway spruce and Scots pine had an intermediate behavior. If accidentally introduced to Europe, the Siberian moth may become especially damaging in forest stands predominated by European larch and by the North American firs. Norway spruce and especially the two-needle pines will be less prone to intensive defoliation by this species. The fact that the pest may damage the range of economically important coniferous species should be taken into account in the pest risk assessment for Europe and also for North America where the Siberian moth occurrence is considered likely.  相似文献   
4.
Israel is a participant in the Earth Resources Technology Satellite Program (ERTS). The imagery of Israel and vicinity taken by the Multi Spectral Scanner of the ERTS-1 Satellite has been the subject of analysis in a multidisciplinary research program. The objectives of the program are mapping of agricultural crops, mainly wheat and orange groves, mapping of natural vegetation, and studies for Israeli hydrology, arid regions research, geology, and oceanography. Cases of water, air, and soil pollution have been observed in the imagery on several dates, and are reported in this paper. These are: oil slicks in the Gulf of Suez and possibly near Haifa; smoke plumes, extending over some 100 km in a nearly straight line along the Gulf of Suez, and soil pollution caused by copper mine effluents in the Arava Valley in Israel. The images of these cases of pollution are presented and ‘space signatures’, i.e., the radiometric spectral characteristics of these cases of pollution as seen from space are also given.  相似文献   
5.
Electrolyzed anodic NaCl solutions [EW+], prepared by the electrolysis of 0.1% NaCl, have been shown to instantly inactivate most pathogens that cause food-borne disease. Elimination of food-borne pathogens does not necessarily guarantee food safety because enterotoxins produced by pathogens may remain active. We have tested whether EW+ can inactivate Staphylococcal enterotoxin A (SEA), one of the major enterotoxins responsible for food poisoning. Fixed quantities of SEA were mixed with increasing molar ratios of EW+, and SEA was evaluated by reversed-phase passive latex agglutination (RPLA) test, immunoassay, native polyacrylamide gel electrophoresis (PAGE), and amino acid analysis after 30 min incubations. Exposure of 70 ng, or 2.6 pmol, of SEA in 25 microL of PBS to a 10-fold volume of EW+, or ca. 64.6 x 10(3)-fold molar excess of HOCl in EW+, caused a loss of immuno-reactivity between SEA and a specific anti-SEA antibody. Native PAGE indicated that EW+ caused fragmentation of SEA, and amino acid analysis indicated a loss in amino acid content, in particular Met, Tyr, Ile, Asn, and Asp. Staphylococcal enterotoxin-A excreted into culture broth was also inactivated by exposure to an excess molar ratio of EW+. Thus, EW+ may be a useful management tool to ensure food hygiene by food processing industries.  相似文献   
6.
Photodynamic therapy (PDT) using a haematoporphyrin derivative (Photogem®, General Physics Institute and clustes Ltda) as photosensitizer and light emitting diodes (LEDs) as the light source was evaluated in 12 cats with cutaneous squamous cell carcinoma. Lesions were illuminated with LEDs, (300 J/cm for 30 min) 24 h after the administration of the photosensitizer. Clinical responses were classified as complete disappearance of the tumour with total re-epithelialization; partial response (a reduction greater than 50%); and no response (less than 50% reduction). Tumours localized to the pinna treated with one ( n  = 3) or two ( n  = 4) applications of PDT yielded no response. Highly invasive tumours of the nose and nasal planum also showed no response, after two treatments ( n  = 2). A combination of PDT and surgery was performed in three cases. Two cats showed partial response and one complete response with one application of therapy 30 days after nasal surgery. Small and noninfiltrative lesions ( n  = 3) of the nasal planum showed a PR with one application ( n  = 2) and a CR with two applications ( n  = 1). This study shows that PDT using Photogem® and LEDs can provide local control of low-grade feline squamous cell carcinoma. The addition of PDT to surgery in more invasive cases may help prevent recurrence.  相似文献   
7.
Efficient syntheses of (Z,E)-5,7-dodecadienol, a pheromone component of the Siberian moth, Dendrolimus superans sibiricus, and (E,Z)-10,12-hexadecadienol, a pheromone component of various Lepidoptera pheromones, were accomplished by cis reduction of the corresponding enynols with activated zinc. The most energetic reagent was zinc galvanized with copper and silver (Zn/Cu/Ag) that achieved rapid and high-yield reduction in methanol-water. The stereoselectivity of semi-hydrogenation was > or =98%. A process whereby zinc dust was continuously activated throughout the reduction with an acid was also satisfactory (95-98% cis). Field evaluation of the 1:1 mixture of (Z,E)-5,7-dodecadienol and (Z,E)-5,7-dodecadienal with the Siberian moth in Russia showed that the rubber septa pretreated with compound and stored at -80 degrees C were as effective as freshly treated septa. Moth responses to septa aged in open air indicated that lure effectiveness declined significantly after 2 weeks of aging. Thus, if rubber septa are used as pheromone dispensers in Siberian moth traps monitoring, they should be replaced biweekly with fresh septa for optimal trap effectiveness.  相似文献   
8.
The fishery biology of mud crabs Scylla spp. was examined using baited traps and gill nets from September 2001 to August 2005 at Iriomote Island, Japan. To elucidate the growth of the crabs, artificially produced S. serrata juveniles were released and recaptured at the study site. The sizes at which 50% of females and males of S. serrata reached sexual maturity (SM50) were estimated as an external carapace width (ECW) based on the morphology of the abdomen and the chela respectively. Two species, S. serrata and S. olivacea, were identified in the area with S. serrata being the dominant species (>95% of the catch). Changes in the mean ECW and the results of the release and recapture experiments suggested that the recruitment of young crabs to the fishery occurred from December/January to April/May. The SM50 of females and males occurred at 132.4 and 150.7 mm ECW respectively. The body size composition of S. serrata revealed that immature crabs comprised approximately 40 and 65% of the catch for females and males respectively. To maintain a sustainable fishery for S. serrata, a minimum landing size based on the SM50 estimates should be implemented as a fishing regulation.  相似文献   
9.
The lead-lead isochron age of chondrules in the CR chondrite Acfer 059 is 4564.7 +/- 0.6 million years ago (Ma), whereas the lead isotopic age of calcium-aluminum-rich inclusions (CAIs) in the CV chondrite Efremovka is 4567.2 +/- 0.6 Ma. This gives an interval of 2.5 +/- 1.2 million years (My) between formation of the CV CAIs and the CR chondrules and indicates that CAI- and chondrule-forming events lasted for at least 1.3 My. This time interval is consistent with a 2- to 3-My age difference between CR CAIs and chondrules inferred from the differences in their initial 26Al/27Al ratios and supports the chronological significance of the 26Al-26Mg systematics.  相似文献   
10.
Deformation on nearby faults induced by the 1999 Hector Mine earthquake   总被引:3,自引:0,他引:3  
Interferometric Synthetic Aperture Radar observations of surface deformation due to the 1999 Hector Mine earthquake reveal motion on several nearby faults of the eastern California shear zone. We document both vertical and horizontal displacements of several millimeters to several centimeters across kilometer-wide zones centered on pre-existing faults. Portions of some faults experienced retrograde (that is, opposite to their long-term geologic slip) motion during or shortly after the earthquake. The observed deformation likely represents elastic response of compliant fault zones to the permanent co-seismic stress changes. The induced fault displacements imply decreases in the effective shear modulus within the kilometer-wide fault zones, indicating that the latter are mechanically distinct from the ambient crustal rocks.  相似文献   
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