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 31 毫秒
1.
Studies of lactic acid bacteria (LAB) as delivery vehicles have focused mainly on the development of mucosal vaccines, with much effort being devoted to the generation of genetic tools for antigen expression in different bacterial locations. Subsequently, interleukins have been co-expressed with antigens in LAB to enhance the immune response that is raised against the antigen. LAB have also been used as a delivery system for a range of molecules that have different applications, including anti-infectives, therapies for allergic diseases and therapies for gastrointestinal diseases. Now that the first human trial with a Lactococcus strain that expresses recombinant interleukin-10 has been completed, we discuss what we have learnt, what we do not yet understand and what the future holds for therapy and prophylaxis with LAB.  相似文献   

2.
Many animals use cues for small-scale navigation, including beacons, landmarks, compasses and geometric properties. Scatter-hoarding animals are a unique system to study small-scale navigation. They have to remember and relocate many individual spatial locations, be fairly accurate in their searching and have to remember these locations for long stretches of time. In this article, we review what is known about cue use in both scatter-hoarding birds and rodents. We discuss the importance of local versus global cues, the encoding of bearings and geometric rules, the use of external compasses such as the Sun and the influence of the shape of experimental enclosures in relocating caches or hidden food. Scatter-hoarding animals are highly flexible in how and what they encode. There also appear to be differences in what scatter-hoarding birds and rodents encode, as well as what scatter-hoarding animals in general encode compared with other animals. Areas for future research with scatter-hoarding animals are discussed in light of what is currently known.  相似文献   

3.
"国际生物多样性观察年"(IBOY)介绍   总被引:2,自引:1,他引:1  
任毅  赵士洞  李云 《生物多样性》2000,8(1):126-129
“国际生物多样性观察年”(IBOY)是由DIVERSITAS所筹划的旨在对全球生物多样性现状从不同层次进行综合研究的一项计划。该计划的主要目标包括:促进公众对生物多样性现状和未来的了解、促进生物多样性学科的发展和完善以及为政府决策过程提供科学依据。DIVERSITAS试图通过该项计划,了解我们所面临的全球性生物多样性现状、全球生物多样性丧失的程度及其原因、生物多样性的丧失给人类生活所带来的威胁、我们怎样保护和发展生物多样性这一人类共同的财富以及探索评估全球生物多样性现状的手段等方面的问题。本文同时还对实施“国际生物多样性观察年”计划所提出的一些提议进行了简要介绍。  相似文献   

4.
5.
If Mammals are the primary hosts of Siphonaptera, 6% of them have changed their trophic appetency for Birds. What are the reasons, what are the adaptations to be adopted by Fleas, what are the families or species groups of fleas concerned, and at last what are the host-families? As to this last question, it is clear that deviation was ecological but not phyletical.  相似文献   

6.
Andrew Hotke 《Bioethics》2014,28(5):255-262
In the last ten years, there have been a number of attempts to refute Julian Savulescu's Principle of Procreative Beneficence; a principle which claims that parents have a moral obligation to have the best child that they can possibly have. So far, no arguments against this principle have succeeded at refuting it. This paper tries to explain the shortcomings of some of the more notable arguments against this principle. I attempt to break down the argument for the principle and in doing so, I explain what is needed to properly refute it. This helps me show how and why the arguments of Rebecca Bennett, Sarah Stoller and others fail to refute the principle. Afterwards, I offer a new challenge to the principle. I attack what I understand to be a fundamental premise of the argument, a premise which has been overlooked in the literature written about this principle. I argue that there is no reason to suppose, as Savulescu does, that morality requires us to do what we have most reason to do. If we reject this premise, as I believe we have reason to do, the argument for Procreative Beneficence fails.  相似文献   

7.
One of the few examples of explicit rationing in the National Health Service is provided by in vitro fertilisation. Of six purchasing authorities examined three have decided against buying in vitro fertilisation while three have decided in favour. The decisions reflect local factors such as the absence or presence of local providers and the views of the public and health professionals. But in vitro fertilisation also illustrates some of the wider issues involved in all decisions about purchasing: questions about what should be provided by the National Health Service, about what procedures should be compared when weighing up value for money, and whether equity demands national decisions about what to provide.  相似文献   

8.
生物质燃料   总被引:6,自引:0,他引:6  
石化资源的溃乏以及其飚升的价格使得今天生物能源的研究越来越受到关注。从传统的生物供能方式——燃烧开始,介绍发酵制气、生物电池等最新的生物供能方式,以求对生物燃料作一较为详细的介绍,并对其应用前景进行展望。  相似文献   

9.
To develop effective protected area policies, scholars and practitioners must better understand the mechanisms through which protected areas affect social and environmental outcomes. With strong evidence about mechanisms, the key elements of success can be strengthened, and the key elements of failure can be eliminated or repaired. Unfortunately, empirical evidence about these mechanisms is limited, and little guidance for quantifying them exists. This essay assesses what mechanisms have been hypothesized, what empirical evidence exists for their relative contributions and what advances have been made in the past decade for estimating mechanism causal effects from non-experimental data. The essay concludes with a proposed agenda for building an evidence base about protected area mechanisms.  相似文献   

10.
Eighteen months on from the publication of "Good Publication Practice for Pharmaceutical Companies," one member of the working group that developed these guidelines reflects on what they have achieved and what has changed since they were first developed.  相似文献   

11.
Yong Zhang 《Luminescence》2010,25(4):290-293
Upconversion nanoparticles (UCNs), in the recent times have attracted attention due to their unique properties, which makes them ideal fluorophores for use in biological applications. There have been various reports on their use for targeted cell imaging, drug and gene delivery and also for diffuse optical tomography. Here we give a brief introduction on what are UCNs and the mechanism of upconversion, followed by a discussion on the biological applications of UCNs and further on what the future holds for UCNs. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

12.
JAMES H. PATTERSON 《Ibis》1995,137(S1):S215-S218
Bird conservation is a global environmental issue which requires innovative approaches to species and habitat protection and management and the promotion of sustainable development practices. This paper presents some of the highlights in the evolution of two programmes, what may or may not have made them succeed, what lessons were learned and what recommendations can be made for the future of bird conservation. The evolution of the North American Waterfowl Management Plan (NAWMP) and Wetlands for the Americas (WA) bears a lot of similarity to the evolution of International Waterfowl and Wetlands Research Bureau and Ramsar.  相似文献   

13.
Interactions between landholders, practitioners and research scientists have greatly influenced landscape restoration activities in South‐eastern Australia. Vegetation connectivity projects undertaken by Holbrook Landcare Network in the Slopes to Summit (S2S) region of South‐eastern Australia have benefitted from the input of both scientists and practitioners. This paper explores what factors support an evidence‐informed restoration outcome, what constrains this and what we can learn from this case.  相似文献   

14.
Viruses are obligate intracellular parasites and have to use the host cell machinery for their replication. Many viruses are able to divert different parts of this machinery to preferentially enhance virus replication at the expense of the cell. The mechanisms by which different viruses do this have, over the years, given us great insight into many cellular processes. Although we still know relatively little about how RNA is exported from the nucleus to the cytoplasm and how this process is regulated, retroviruses have already emerged as one of the most important model systems for these studies. This review will attempt to summarize what we have learnt from these viruses to date and what we hope to achieve in the near future.  相似文献   

15.
Zebrafish provide unique opportunities for optogenetic studies of behavior. Here, we review the most recent work using optogenetic and imaging approaches to study the neuronal circuits controlling movements in the transparent zebrafish. Specifically, we focus on what we have learned from zebrafish about neuronal migration, network formation and behavioral control, and what the future may hold.  相似文献   

16.
17.
Captive populations for the primary purpose of securing the survival of species through stable self-sustaining populations need to be founded and managed according to sound scientific principles. Given the current rate of habitat fragmentation and its effect on animal populations, species conservation over the long term increasingly will require management to reduce risk of extinction. This may include ex situ populations which can support and interact demographically and genetically with wild populations. This paper presents a review of what can be achieved through a multidisciplinary approach, involving science, interactive management, politics, environmental education, habitat preservation and habitat restoration. Examples of what conservation-oriented breeding programmes have contributed to date, what represents a viable population and what is meant by effective conservation are provided, and various scenarios for the future are discussed.  相似文献   

18.

1. 1. Results from more than half a century of investigation of human adaptation to cold have been so varied that some observers have doubted whether man can adapt to cold at all.

2. 2. This paper considers what challenges to the thermoregulatory system humans experience when living and working in a cold environment (specifically the Antarctic and Subantarctic), what kinds of adaptation have been shown to develop, and what factors might have contributed to the diversity of opinion.

Author Keywords: Cold stress; polar regions; human adaptation to cold; vasomotor responses; clothing  相似文献   


19.
Recent palaeobotanical discoveries assisted by the thorough morphological analysis of 'living fossils'-archaic extant plants-have brought to light many unexpected features of the early angiosperms and their immediate precursors, while studies in palaeoecology have provided a basis for deciphering the chronology of evolutionary events and their environmental forcing. Our previous ideas of what is primitive and what angiosperm ancestors looked like are presently under revision. We now have a clearer picture of how macroevolution proceeds and how a large taxon could come into being.  相似文献   

20.
Anthropologists have long been aware of the difference between the ideal pattern in society (what people think should or should not be done) and real behavior (what actually is done). This article calls attention to the importance of a third element, presumed behavior, or what people think is being done in the society. Since people tend to act on the basis of what they think others are doing (which may not coincide at all with what people are actually doing, or with the ideal pattern) knowledge of the presumed behavior is highly significant in understanding and predicting social behavior.  相似文献   

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