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161.
Plant growth-promoting rhizobacteria and arbuscular mycorrhizal (AM) fungi represent two main groups of beneficial microorganisms of the rhizosphere. The role of different strains of Azospirillum on AM fungi development was evaluated by measuring the percentage of AM colonisation of the root system in durum wheat and maize plants, grown under both greenhouse and field conditions. The effect of wild-type Azospirillum brasilense strain Sp245 and genetically modified (GM) derivatives overproducing indole-3-acetic acid was assessed at greenhouse level in (1) three different cultivars of durum wheat, in the presence of indigenous AM fungi and (2) maize plants artificially inoculated with Glomus mosseae and Glomus macrocarpum. In addition, the establishment of natural AM fungal symbiosis was evaluated using Azospirillum lipoferum CRT1 in maize plants at field level. Despite the stimulatory effect of the different Azospirillum inocula on root growth, no significant differences in AM colonisation were found, independently of the AM fungus involved, either in wheat or in maize plants. Similarly, GM A. brasilense, which strongly stimulates root development, did not affect AM formation. Although these results were obtained in conditions in which the mycorrhization rate was moderate (15–30%), overall considered they indicate that the use of wild-type or GM Azospirillum phytostimulators does not alter mycorrhization.  相似文献   
162.
The disappearance of azoxystrobin, pyrimethanil, cyprodinil, and fludioxonil on tomatoes in greenhouse was studied. At the preharvest interval, except for cyprodinil, the pesticide residues were below the MRL fixed in Italy. The mechanism of disappearance studied with model systems shows that the decrease in residues was due to codistillation and photodegradation in pyrimethanil, to photodegradation in fludioxonil, and to evaporation and codistillation in cyprodinil. Azoxystrobin residues were stable during all experiments.  相似文献   
163.
The Shallow Radar (SHARAD) on the Mars Reconnaissance Orbiter has imaged the internal stratigraphy of the north polar layered deposits of Mars. Radar reflections within the deposits reveal a laterally continuous deposition of layers, which typically consist of four packets of finely spaced reflectors separated by homogeneous interpacket regions of nearly pure ice. The packet/interpacket structure can be explained by approximately million-year periodicities in Mars' obliquity or orbital eccentricity. The observed approximately 100-meter maximum deflection of the underlying substrate in response to the ice load implies that the present-day thickness of an equilibrium elastic lithosphere is greater than 300 kilometers. Alternatively, the response to the load may be in a transient state controlled by mantle viscosity. Both scenarios probably require that Mars has a subchondritic abundance of heat-producing elements.  相似文献   
164.
On 4 July 2005, many observatories around the world and in space observed the collision of Deep Impact with comet 9P/Tempel 1 or its aftermath. This was an unprecedented coordinated observational campaign. These data show that (i) there was new material after impact that was compositionally different from that seen before impact; (ii) the ratio of dust mass to gas mass in the ejecta was much larger than before impact; (iii) the new activity did not last more than a few days, and by 9 July the comet's behavior was indistinguishable from its pre-impact behavior; and (iv) there were interesting transient phenomena that may be correlated with cratering physics.  相似文献   
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We investigated roost selection by Barbastella barbastellus in a mountainous area of central Italy. Twenty-five bats, mostly lactating females, were radio-tracked to 33 roost trees. Trees in unmanaged woodland were favoured as roost trees; woodland subject to limited logging was used in proportion to availability, and areas where open woodland and pasture occurred were avoided. Selection depended on tree condition (dead beech trees were preferred) and height (roost trees were taller than random ones). Cavity selection was based on cavity type, height and entrance direction: roost cavities were mainly beneath loose bark, at a greater height above ground and facing south more frequently than random cavities. Untouched areas of mature woodland should be preserved to provide roosting conditions for B. barbastellus. In logged areas, harvesting protocols should save dead and mature trees; frequent roost switching and small colony size imply that large numbers of roost trees are needed.  相似文献   
167.
Psychological responses after abortion   总被引:8,自引:0,他引:8  
A review of methodologically sound studies of the psychological responses of U.S. women after they obtained legal, nonrestrictive abortions indicates that distress is generally greatest before the abortion and that the incidence of severe negative responses is low. Factors associated with increased risk of negative response are consistent with those reported in research on other stressful life events.  相似文献   
168.
A series of high-resolution computed x-ray tomography (CT) images of the normal canine middle and inner ear are presented to serve as a reference for optimal interpretation of clinical CT images of animals with diseases affecting this region.  相似文献   
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170.

The aim of this work was to verify whether polymorphisms in candidate genes for litter size segregate in Italian Large White (ITLW) pigs. We genotyped 120 sows that belonged to six different farms for 10 single nucleotide polymorphisms (SNPs) of 10 different genes. Polymorphisms in the chosen genes had already been associated with litter-size traits in other pig populations and were candidates for function and/or chromosomal location. The results indicated that the CLGN, pDAZL, and RFN4 SNPs were not segregating in the genotyped samples. The remaining seven markers were polymorphic with minor allele frequencies ranging from 0.10 (AFP) to 0.48 (RBP4). Because of the observed genetic variabilities in the investigated loci, the polymorphisms in the AFP, BMPR1B, CXCL10, ESR2, GNRHR, MAN2B2, and RBP4 genes can be considered suitable markers for association studies with litter-size traits in ITLW pigs.

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