首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Nitrification, a microbial process, is a key component and integral part of the nitrogen (N) cycle. Soil N is in a constant state of flux, moving and changing chemical forms. During nitrification, a relatively immobile N-form (NH 4 +) is converted into highly mobile nitrate-N (NO 3 ?). The nitrate formed is susceptible to losses via leaching and conversion to gaseous forms via denitrification. Often less than 30% of the applied N fertilizer is recovered in intensive agricultural systems, largely due to losses associated with and following nitrification. Nitrogen-use efficiency (NUE) is defined as the biomass produced per unit of assimilated N and is a conservative function in most biological systems. A better alternative is to define NUE as the dry matter produced per unit N applied and strive for improvements in agronomic yields through N recovery. Suppressing nitrification along with its associated N losses is potentially a key part in any strategy to improve N recovery and agronomic NUE. In many mature N-limited ecosystems, nitrification is reduced to a relatively minor flux. In such systems there is a high degree of internal N cycling with minimal loss of N. In contrast, in most high-production agricultural systems nitrification is a major process in N cycling with the resulting N losses and inefficiencies. This review presents the current state of knowledge on nitrification and associated N losses, and discusses strategies for controlling nitrification in agricultural systems. Limitations of the currently available nitrification inhibitors are highlighted. The concept of biological nitrification inhibition (BNI) is proposed for controlling nitrification in agricultural systems utilizing traits found in natural ecosystems. It is emphasized that suppression of nitrification in agricultural systems is a critical step required for improving agronomic NUE and maintaining environmental quality.  相似文献   

2.
3.
4.
Ongoing changes in attention and cognition depend upon cortical/subcortical interactions, which select sequences of different spatial patterns of activation in the cortex.  相似文献   

5.
Transport of macromolecules into and out of the nucleus is generally effected by targeting signals that are recognized by specific members of the importin/exportin transport receptor family. The latter mediate passage through the nuclear envelope-embedded nuclear pore complexes (NPCs) by conferring interaction with NPC constituents, as well as with other components of the nuclear transport machinery, including the guanine nucleotide-binding protein Ran. Importantly, nuclear transport is regulated at multiple levels via a diverse range of mechanisms, such as the modulation of the accessibility and affinity of target signal recognition by importins/exportins, with phosphorylation/dephosphorylation as a major mechanism. Alteration of the level of the expression of components of the nuclear transport machinery also appears to be a key determinant of transport efficiency, having central importance in development, differentiation and transformation.  相似文献   

6.
From a genomic library enriched for GA/CA repeats, 15 highly polymorphic microsatellite markers were developed for Cariniana estrellensis, a tropical forest tree. The microsatellite loci were screened in 49 mature trees found between Pardo river and Mogi-Guaçu river basins, in the state of São Paulo, Brazil. A total of 140 alleles were detected with an average of 9.33 alleles per locus. The expected heterozygosity ranged from 0.37 to 0.88. These loci showed a high probability of paternity exclusion. Additionally, 12 loci were effectively transferred to Cariniana legalis. High levels of polymorphism make the present SSR markers useful for population genetic studies.  相似文献   

7.
8.
9.
10.
LifeMap Discovery™ provides investigators with an integrated database of embryonic development, stem cell biology and regenerative medicine. The hand-curated reconstruction of cell ontology with stem cell biology; including molecular, cellular, anatomical and disease-related information, provides efficient and easy-to-use, searchable research tools. The database collates in vivo and in vitro gene expression and guides translation from in vitro data to the clinical utility, and thus can be utilized as a powerful tool for research and discovery in stem cell biology, developmental biology, disease mechanisms and therapeutic discovery. LifeMap Discovery is freely available to academic nonprofit institutions at http://discovery.lifemapsc.com  相似文献   

11.
The purpose of this study was to develop the Human–Animal Interaction Scale (HAIS) and evaluate its reliability and validity. The HAIS is a 24-item self-report instrument designed to describe and quantify behaviors performed by humans and nonhuman animals during an episode of interaction (e.g., engaging with a pet, participating in an animal-assisted intervention). Participants were 295 adult volunteers who completed the HAIS in one of several different contexts, including both laboratory and applied settings. The scale was tested across several different species, including companion animals (i.e., dogs and cats), small caged animals (i.e., rats, rabbit, hedgehog), and horses. Analyses indicate good reliability, with a Cronbach’s alpha of 0.82 overall and alphas of 0.72 and higher across the different species and settings. Test-retest analyses indicate ratings remain consistent up to one week following an interaction. Evidence of construct validity was gathered by comparing HAIS ratings with other well-established measures of related constructs, as well as comparing participant reports with researcher observations. Potential uses in basic and applied research are discussed.  相似文献   

12.
13.
14.
Karin Friederic 《Ethnos》2014,79(5):650-676
ABSTRACT

In the Ecuadorian public imaginary, Manabí province is constructed as a lawless frontier. Manaba men are characterized for their aggressive masculinity, robust and primitive sexuality, and their proclivity towards resolving conflict with violence. This paper examines community debates about brothels and healthy sexuality in a rural coastal region where the state is expanding its reach into domestic life via the regulation of sexual intimacies and family violence. Local debates about healthy sexuality embody the historically contested and currently changing nature of state–community relationships in this previously marginalized region. While certain community factions invoke modernizing discourses of women's rights in their struggle to shut down brothels and mitigate family violence, others argue for unregulated sexuality as a way to diminish violence. Drawing from over 10 years of ethnographic research on gender, violence, and human rights in Ecuador, this paper reveals the co-construction of rural intimacies and the boundaries of state intervention.  相似文献   

15.

Background and Objective

Several studies assessed the efficacy of traditional Chinese medical exercise in the management of Parkinson’s disease (PD), but its role remained controversial. Therefore, the purpose of this systematic review is to evaluate the evidence on the effect of traditional Chinese medical exercise for PD.

Methods

Seven English and Chinese electronic databases, up to October 2014, were searched to identify relevant studies. The PEDro scale was employed to assess the methodological quality of eligible studies. Meta-analysis was performed by RevMan 5.1 software.

Results

Fifteen trials were included in the review. Tai Chi and Qigong were used as assisting pharmacological treatments of PD in the previous studies. Tai Chi plus medication showed greater improvements in motor function (standardized mean difference, SMD, -0.57; 95% confidence intervals, CI, -1.11 to -0.04), Berg balance scale (BBS, SMD, -1.22; 95% CI -1.65 to -0.80), and time up and go test (SMD, -1.06; 95% CI -1.44 to -0.68). Compared with other therapy plus medication, Tai Chi plus medication also showed greater gains in motor function (SMD, -0.78; 95% CI -1.46 to -0.10), BBS (SMD, -0.99; 95% CI -1.44 to -0.54), and functional reach test (SMD, -0.77; 95% CI -1.51 to -0.03). However, Tai Chi plus medication did not showed better improvements in gait or quality of life. There was not sufficient evidence to support or refute the effect of Qigong plus medication for PD.

Conclusions

In the previous studies, Tai Chi and Qigong were used as assisting pharmacological treatments of PD. The current systematic review showed positive evidence of Tai Chi plus medication for PD of mild-to-moderate severity. So Tai Chi plus medication should be recommended for PD management, especially in improving motor function and balance. Qigong plus medication also showed potential gains in the management of PD. However, more high quality studies with long follow-up are warrant to confirm the current findings.  相似文献   

16.
  1. Download : Download high-res image (99KB)
  2. Download : Download full-size image
  相似文献   

17.
It is out of question that China has achieved considerable advancements in science and technology. The worldwide spread of "Made in China" that gets on the western countries' nerves is a good illustration. However, although comparatively better than some other developing countries, we have to face the situation that science and technology in such a great nation as China is still seriously lagged behind, lacking great breakthroughs and top-ranking masters and leaders. That's why we feel uneasy in front of international colleagues.  相似文献   

18.
The emergence of SARS-CoV-2 in late 2019 and human responses to the resulting COVID-19 pandemic in early 2020 have rapidly changed many aspects of human behavior, including our interactions with wildlife. In this commentary, we identify challenges and opportunities at human–primate interfaces in light of COVID-19, focusing on examples from Asia, and make recommendations for researchers working with wild primates to reduce zoonosis risk and leverage research opportunities. First, we briefly review the evidence for zoonotic origins of SARS-CoV-2 and discuss risks of zoonosis at the human–primate interface. We then identify challenges that the pandemic has caused for primates, including reduced nutrition, increased intraspecific competition, and increased poaching risk, as well as challenges facing primatologists, including lost research opportunities. Subsequently, we highlight opportunities arising from pandemic-related lockdowns and public health messaging, including opportunities to reduce the intensity of problematic human–primate interfaces, opportunities to reduce the risk of zoonosis between humans and primates, opportunities to reduce legal and illegal trade in primates, new opportunities for research on human–primate interfaces, and opportunities for community education. Finally, we recommend specific actions that primatologists should take to reduce contact and aggression between humans and primates, to reduce demand for primates as pets, to reduce risks of zoonosis in the context of field research, and to improve understanding of human–primate interfaces. Reducing the risk of zoonosis and promoting the well-being of humans and primates at our interfaces will require substantial changes from “business as usual.” We encourage primatologists to help lead the way.  相似文献   

19.
20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号