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151.
Iwona Żur Andrzej Skoczowski Sebastian Pieńkowski Franciszek Dubert 《Acta Physiologiae Plantarum》2002,24(1):11-17
The uptake rate of 14C-labelled sucrose, myo-inositol and PC was studied in callus cultures of two oilseed rape cultivars, characterized by different in vitro regeneration ability. Transfer of calli onto regeneration stimulating medium resulted in changes of examined substances uptake
rate, which were depended on tissue morphogenic potential. Non-regenerating calli of both cultivars increased uptake rate
of sucrose whereas changes in incorporation of other compounds were under genome control. Significant increase of uptake rate
of all tested compounds was observed as result of organogenesis initiation. Such differences, in the responses of organogenic
and non-organogenic tissue indicate that this parameter could be useful as marker of organogenesis
A correlation was observed between the rate of sucrose uptake and its concentration in the medium, which suggests an advantage
to passive transport through the callus cell membrane. Lack of such correlation in the case of other labels indicates that
this processes are selective and under cell control. 相似文献
152.
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154.
Malcolm Parker 《Journal of bioethical inquiry》2007,4(1):7-19
The convergence of complementary and alternative medicine (CAM) and evidence-based medicine (EBM) is a prominent feature of
healthcare in western countries, but it is currently undertheorised, and its implications have been insufficiently considered.
Two models of convergence are described – the totally integrated evidence-based model (TI) and the multicultural-pluralistic
model (MP). Both models are being incorporated into general medical practice. Against the background of the reasons for the
increasing utilisation of CAM by the public and by general practitioners, TI-convergence is supported and MP-convergence is
rejected. MP-convergence is epistemologically and clinically incoherent, and it cannot be regulated. It is also inconsistent
with developments in the legal determination of the standard of care for both diagnosis/treatment and disclosure. These claims
concerning MP-convergence are justified by the fact that science is not a member of the group of perspectives or world-views
which postmodernism treats as equally valid, and this is especially important for healthcare. 相似文献
155.
SUMMARY Small stockwatering dams are usually ignored in the Transkei and Ciskei in fishfarming ventures. This paper reports on experimental results in fish production studies, using Aischgrund carp, which were obtained in the Ciskei and which indicate that economically worthwhile fish production can be achieved in such dams. 相似文献
156.
Anne Gro Vea Salvanes Olav Moberg Lars O. E. Ebbesson Tom Ole Nilsen Knut Helge Jensen Victoria A. Braithwaite 《Proceedings. Biological sciences / The Royal Society》2013,280(1767)
Different kinds of experience during early life can play a significant role in the development of an animal''s behavioural phenotype. In natural contexts, this influences behaviours from anti-predator responses to navigation abilities. By contrast, for animals reared in captive environments, the homogeneous nature of their experience tends to reduce behavioural flexibility. Studies with cage-reared rodents indicate that captivity often compromises neural development and neural plasticity. Such neural and behavioural deficits can be problematic if captive-bred animals are being reared with the intention of releasing them as part of a conservation strategy. Over the last decade, there has been growing interest in the use of environmental enrichment to promote behavioural flexibility in animals that are bred for release. Here, we describe the positive effects of environmental enrichment on neural plasticity and cognition in juvenile Atlantic salmon (Salmo salar). Exposing fish to enriched conditions upregulated the forebrain expression of NeuroD1 mRNA and improved learning ability assessed in a spatial task. The addition of enrichment to the captive environment thus promotes neural and behavioural changes that are likely to promote behavioural flexibility and improve post-release survival. 相似文献
157.
Jinguang Zhang 《Evolution and human behavior》2018,39(5):556-565
General trust is trust extended to people from outside one's immediate social network. Two studies have tested a parasite stress explanation of general trust using cross-cultural data, showing a linear negative correlation between parasite stress and trust in “most people.” However, recent studies suggest that 1) trust in most people as a measure of general trust confounds ingroup trust and outgroup trust in cross-cultural surveys and 2) parasite stress can curvilinearly correlate with variables of ingroup embeddedness and outgroup avoidance. Using data from the World Value Survey (WVS) Waves 5 and 6 (N?=?117,370 from 80 countries and geopolitical regions), we found no evidence that parasite stress—measured either as contemporary non-sexually-transmitted-disease (non-STD) stress or as historical pathogen prevalence—curvilinearly correlated with ingroup trust. However, parasite stress significantly curvilinearly correlated with outgroup trust, and the two-line test confirmed that the correlation was U-shaped. This research extends previous work on parasite stress and trust, informs the recent debate on whether parasite stress relates to outgroup avoidance, and suggests directions for developing the parasite stress theory of values and sociality. 相似文献
158.
Data obtained from studies in the health sciences often have incompletely observed covariates as well as censored outcomes. In this paper, we present methods for fitting the log-F accelerated failure time model with incomplete continuous and/or categorical time-independent covariates using the Gibbs sampler. A general location model that allows different covariance structures across cells is specified for the covariates, and ignorable missingness of the covariates is assumed. Techniques that accommodate standard assumptions of ignorable censoring as well as certain types of nonignorable censoring are developed. We compare our approach to traditional complete-case analysis in an application to data obtained from a study of melanoma. The comparison indicates that substantial gains in efficiency are possible with our approach. 相似文献
159.
六倍体小黑麦T型细胞质雄性不育体系杂种优势与配合力的研究 总被引:11,自引:0,他引:11
用具提莫菲维小麦细胞质的六倍体小黑麦的3个不育系和3个恢复系作为亲本,进行3×3不完全双列杂交,对所组配的F1代8个农艺性状的杂种优势分析结果表明,除千粒重外,其余性状出现正向超亲优势的组合较少,多数呈低亲或中亲遗传,且各组合间的差异比较显著。配合力分析表明,一般配合力与特殊配合力的方差均达到了显著水平,F1各性状均受基因加性效应和非加性效应共同作用;从总体上看,不育系A1、A2及恢复系R1、R2的一般配合力良好,其配制的组合优势较强,具一定的利用价值。对一般配合力与亲本表型值进行了相关分析,二者无显著的相关关系。 相似文献
160.
Arginine residues are generally considered poor candidates for the role of general bases because they are predominantly protonated at physiological pH. Nonetheless, Arg residues have recently emerged as general bases in several enzymes: IMP dehydrogenase, pectate/pectin lyases, fumarate reductase, and l-aspartate oxidase. The experimental evidence suggesting this mechanistic function is reviewed. Although these enzymes have several different folds and distinct evolutionary origins, a common structural motif is found where the critical Arg residue is solvent accessible and adjacent to carboxylate groups. The chemistry of the guanidine group suggests unique strategies to lower the pK(a) of Arg. Lastly, the presumption that general bases must be predominantly deprotonated is revisited. 相似文献