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161.
We estimated nitrogen (N) use by trees of three poplar species exposed for 3 years to free air CO(2) enrichment (FACE) and determined whether the CO(2) treatment affected the future N availability of the plantation. Trees were harvested at the end of the first 3-year rotation and N concentration and content of woody tissues determined. Nitrogen uptake of fine roots and litter was measured throughout the first crop rotation. The results were related to previously published variations in soil N content during the same period. We estimated retranslocation from green leaves and processes determining N mobilization and immobilization, such as mineralization and nitrification, and N immobilization in litter and microbial biomass. In all species, elevated CO(2) concentration ([CO(2)]) significantly increased nitrogen-use efficiency (NUE; net primary productivity per unit of annual N uptake), decreased N concentration in most plant tissues, but did not significantly change cumulative N uptake by trees over the rotation. Total soil N was depleted more in elevated [CO(2)] than in ambient [CO(2)], although not significantly for all soil layers. The effect of elevated [CO(2)] was usually similar for all species, although differences among species were sometimes significant. During the first 3-year rotation, productivity of the plantation remained high in the elevated [CO(2)] treatment. However, we observed a potential reduction in N availability in response to elevated [CO(2)].  相似文献   
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163.
Schmallenberg virus (SBV), a novel arboviral pathogen, has emerged and spread across Europe since 2011 inflicting congenital deformities in the offspring of infected adult ruminants. Several species of Culicoides biting midges (Diptera: Ceratopogonidae) have been implicated in the transmission of SBV through studies conducted in northern Europe. In this study Culicoides from SBV outbreak areas of mainland France and Italy (Sardinia) were screened for viral RNA. The role of both C. obsoletus and the Obsoletus complex (C. obsoletus and C. scoticus) in transmission of SBV were confirmed in France and SBV was also discovered in a pool of C. nubeculosus for the first time, implicating this species as a potential vector. While collections in Sardinia were dominated by C. imicola, only relatively small quantities of SBV RNA were detected in pools of this species and conclusive evidence of its potential role in transmission is required.  相似文献   
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165.
The genealogical data of 471 (whole population: WP) Lizard canaries of an Italian breeder were analyzed to evaluate the genetic variability of the breed. The reference population (RP) comprised 346 living reproductive birds. Average generation interval was 1.61 ± 0.718 for males and 1.72 ± 0.863 for females. The average value of inbreeding (F) and relatedness (AR) in the RP were 15.83% and 22.63%, while the average increase in inbreeding was estimated to be 6.71% per generation (effective population size = 7.49). The results showed the need to reduce the level of inbreeding which would result in significant loss of genetic variation and in significant inbreeding depression.  相似文献   
166.
Endogenous opioid binding to micro receptors is hypothesized to mediate natural rewards and has been proposed to be the basis of infant attachment behavior. Here, we report that micro-opioid receptor knockout mouse pups emit fewer ultrasonic vocalizations when removed from their mothers but not when exposed to cold or male mice odors. Moreover these knockout pups do not show a preference toward their mothers' cues and do not show ultrasonic calls potentiation after brief maternal exposure. Results from this study may indicate a molecular mechanism for diseases characterized by deficits in attachment behavior, such as autism or reactive attachment disorder.  相似文献   
167.
Mutations in DKC1 cause dyskeratosis congenita (DC), a disease characterized by premature aging and increased tumor susceptibility. The DKC1 protein binds to the box H + ACA small nucleolar RNAs and the RNA component of telomerase. Here we show that hypomorphic Dkc1 mutant (Dkc1m) mice recapitulate in the first and second generations (G1 and G2) the clinical features of DC. Dkc1m cells from G1 and G2 mice were impaired in ribosomal RNA pseudouridylation before the onset of disease. Reductions of telomere length in Dkc1m mice became evident only in later generations. These results suggest that deregulated ribosome function is important in the initiation of DC, whereas telomere shortening may modify and/or exacerbate DC.  相似文献   
168.
The molecular factors involved in the three-way interaction between plant, pathogenic fungi and antagonistic/biocontrol fungi, such as Trichoderma, are still poorly understood, even if they represent a matter of interest for improving crop management and developing new strategies for plant diseases control. The aim of this work is to investigate the components involved in this interaction and, for this purpose, a proteomic approach was used. 2-D maps of the protein extracts from the single co…  相似文献   
169.
A degenerate gas of identical fermions is brought to collapse by the interaction with a Bose-Einstein condensate. We used an atomic mixture of fermionic potassium-40 and bosonic rubidium-87, in which the strong interspecies attraction leads to an instability above a critical number of particles. The observed phenomenon suggests a direction for manipulating fermion-fermion interactions on the route to superfluidity.  相似文献   
170.
The problems that relate to the outermost limits of institutional care, if such limits exist, will certainly be among the most salient problems during the coming years-no matter whether such care proceeds on an inpatient or an outpatient basis. Whatever course may be taken will certainly affect the lives of every citizen in urbanized and industrialized society. At present in California there is considerable shifting of individuals from one care status or category to another, in efforts to find accommodations that will better reflect the realities of modern existence. However, such shifting of caseloads as the moving of individuals from nursing and convalescent homes to hospitals and back again does not constitute a change, either from the standpoint of the subjects involved or from the standpoint of significantly affecting the overall caseload. Most commonly, the shifting of caseloads has been merely jurisdictional. Much the same can be said of the transfers from a police agency to welfare, or vice versa. Similarly, a shift from inpatient status to outpatient status does not constitute a significant change. Such transfers from one jurisdiction to another reflect a reduction in caseload for one agency, but a corresponding increase in caseload for another. Thus, there has been no significant change in the subject population as such. Jurisdictional transfers are often merely caretaking actions that reflect bureaucratic decisions. Equally often, such decisions do not address themselves to the basic priorities that guide the functions of caretaking. Explicitly stated priorities must supersede jurisditional transfers if the concept of caretaking is to include better resources for human development and if the subject population is to participate in the managing of institutions. On any given day during 1969 in the state of California, virtually 8 million people from an estimated population of 19,800,000 were under some form of institutional care or in some institutional program, or were employed to provide the care and administer the programs. Clearly this is a vast effort toward the training and retraining, as well as the rehabilitation of people, in the traditional sense of these words. The salient problems that have emerged from this context of urban and industrial development involve social control, social mobility, organizational behavior by caretakers and subjects, minority peoples, and the extensions of institutions into communities. Given these developments, is it not proper to ask whether or not the nature of urbanized and industrialized society has changed to such a point that a return to the past (and past solutions) is no longer feasible? Is it not also proper to ask what voice the subject population will have in helping to guide the urban and industrialized state into the future? And certainly there is a question that virtually everyone will ask: What percentage of tax revenues (whether shared or under direct programs) shall be destined to better meet the problems of this future society, which, it seems, is already upon us?  相似文献   
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