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991.
Climate-driven increases in wildfires, drought conditions, and insect outbreaks are critical threats to forest carbon stores. In particular, bark beetles are important disturbance agents although their long-term interactions with future climate change are poorly understood. Droughts and the associated moisture deficit contribute to the onset of bark beetle outbreaks although outbreak extent and severity is dependent upon the density of host trees, wildfire, and forest management. Our objective was to estimate the effects of climate change and bark beetle outbreaks on ecosystem carbon dynamics over the next century in a western US forest. Specifically, we hypothesized that (a) bark beetle outbreaks under climate change would reduce net ecosystem carbon balance (NECB) and increase uncertainty and (b) these effects could be ameliorated by fuels management. We also examined the specific tree species dynamics—competition and release—that determined NECB response to bark beetle outbreaks. Our study area was the Lake Tahoe Basin (LTB), CA and NV, USA, an area of diverse forest types encompassing steep elevation and climatic gradients and representative of mixed-conifer forests throughout the western United States. We simulated climate change, bark beetles, wildfire, and fuels management using a landscape-scale stochastic model of disturbance and succession. We simulated the period 2010–2100 using downscaled climate projections. Recurring droughts generated conditions conducive to large-scale outbreaks; the resulting large and sustained outbreaks significantly increased the probability of LTB forests becoming C sources over decadal time scales, with slower-than-anticipated landscape-scale recovery. Tree species composition was substantially altered with a reduction in functional redundancy and productivity. Results indicate heightened uncertainty due to the synergistic influences of climate change and interacting disturbances. Our results further indicate that current fuel management practices will not be effective at reducing landscape-scale outbreak mortality. Our results provide critical insights into the interaction of drivers (bark beetles, wildfire, fuel management) that increase the risk of C loss and shifting community composition if bark beetle outbreaks become more frequent.  相似文献   
992.
Journal of Physiology and Biochemistry - Infants born small for gestational age (SGA) are at increased risk of perinatal morbidity, persistent short stature, and metabolic alterations in later...  相似文献   
993.
The genetic diversity at the ELA DQβ locus was investigated using polymerase chain reaction and DNA sequencing. Based upon serological methods 16 class II homozygous animals were selected and their genomic DNA was used. A DQβ gene from an equine cDNA library was also sequenced. Our methology and the similarity between the genomic and the cDNA sequences suggest that the studied locus is expressed on equine lymphocytes. In the predicted amino acid sequence the most extensive variation is located at residues 56–60. The pattern of these five amino acids is strongly correlated to the serological ELA class II specificities (W13, W22, W23, Be200). The alleles corresponding to the W23 specificity are the most divergent among the equine DQβ alleles and also from other mammalian DQβ sequences.  相似文献   
994.
The effects of natural blooms of Heterosigma akashiwo on freshwater-and saltwater-acclimated juvenile chinook salmon were assessed. Rates of fish mortality in the blooms were independent of acclimation of fish to seawater and the ambient oxygen levels, but were dependent on concentration of algae and ambient water temperatures. No pathological abnormality to gills or other internal organs in the fish were evident. Aeration or oxygenation of fish cages did not enhance or inhibit fish survival in a H. akashiwo bloom. Cause of death was considered to be due to a labile ichthyotoxic agent.  相似文献   
995.
Two new capsalid species, Pseudallobenedenia arabica n. sp. from the gills of Pristipomoides filamentosus (Lutjanidae) from the Arabian Sea and Lagenivaginopseudobenedenia tinrowi n. sp. from the gills of Etelis carbunculus (Lutjanidae) from the eastern Pacific Ocean are described and illustrated. P. arabica differs from the most similar species, P. opakapaka Yamaguti, 1966, in the greater width of the body, its larger haptor and anterior adhesive discs, the form and sizes of the testes and ovary, and differences in host and locality. L. tinrowi differs from its congener, L. etelis Yamaguti, 1966, in the larger size of the body and its organs, the absence of eye-spots and Goto's glands, and differences in the arrangement of the genital organs. All of the species in these two genera differ from other capsalids by the presence of a voluminous uterus and an extremely long penis forming a loop. All species in these two genera are parasites of fishes of the family Lutjanidae and are reported from Indo-Pacific subtropical areas.  相似文献   
996.
The results of the use of cefepime (Maxipime) combination with amikacin vs ceftriaxon combination with amikacin in the treatment of 80 patients with different forms of hemoblastosis are presented. Severe infectious complications in the patients were associated with prolonged and deep neutropenia during inductive or antirelapsing chemotherapy. All the patients in the trial were from the group of high risk of infectious complications with the blood neutrophil count under 100 cells/microliter. The duration of neutropenia averaged 12 days (7 to 15). The average period of the treatment with cefepime and amikacin equaled to 13 days (8 to 16). The treatment with cefepime + amikacin was successful in 38 out of 40 patients (95%). The average period of the treatment with ceftriaxon and amikacin equaled to 14 days (7 to 18). The efficacy of the treatment with ceftriaxon + amikacin was 60% (24 patients out of 40).  相似文献   
997.
The generation and characterization of new sheep-hamster cell hybrids is reported from the fusion of sheep white blood cells with six different hamster auxotrophs. Selection from these and previously generated cell hybrids has led to the production of a panel of 30 hybrids covering the complete sheep genome of 28 chromosomes. Over half of the cell hybrids in this panel contain single sheep chromosomes. By complementation, the following new assignments have been made using the panel: phosphoribosyl N-formylglycinamide amidotransferase (PRFGA) to sheep chromosome (chr) 11; adenylosuccinate synthetase (ADSS) to sheep chr 12; adenylosuccinate lyase (ADSL) to sheep chr 3q; 3-hydroxy-3-methylglutaryl-coenzyme A synthase (HMGCS) to sheep chr 16; dihydrofolate reductase (DHFR) to sheep chr 5; and adenine phosphoribosyltransferase (APRT) to sheep chr 14. The gene phosphoribosylaminoinidazole-carboxamide formyltransferase/Inosinicase (PRACFT) has now been regionally assigned to chr 2q. By isozyme analysis, phosphogluconate dehydrogenase (PGD) was assigned to sheep chr 12, anchoring the sheep syntenic group U1 to this chromosome, and mannose phosphate isomerase (MPI) was assigned to sheep chr 18. Furthermore, the chromosomal assignment of 110 microsatellites was confirmed using this cell panel.  相似文献   
998.
Summary Bacteria from recreational waters collected from two Lake Erie beaches in Dunkirk, New York were plated onto m Endo LES media. The 16S rRNA gene was then amplified from coliform and non-coliform bacteria using the polymerase chain reaction. The PCR products were characterized by restriction fragment length polymorphism (RFLP) analysis. A total of 8 RFLP groups were identified from the analysis of 920 samples and selected PCR products from each group were sequenced. The DNA sequence analysis indicated that more than half of the bacteria identified as coliforms on the m Endo plates belonged to the genus Aeromonas from the family Aeromonadaceae. Most of the remaining coliforms were from the Enterobacteriaceae. The data indicate that m Endo agar plates allow the growth of non-coliform bacteria, especially Aeromonas species.  相似文献   
999.
1000.
Arundo donax L. (Poaceae) is native to Mediterranean Europe and invasive in the Rio Grande Basin of North America. Rhizomes from nine sites in France and Spain infested with a candidate control agent, the armoured scale Rhizaspidiotus donacis (Hemiptera: Diaspididae) weighed 50% less than those from nine sites without scale.  相似文献   
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