宏观植物生态模型的研究现状与展望

概述了3种主要植物生态模型的发展现状1)种群动态模型,主要模拟在一个生态系统中单个种的植物个体发芽、成长和死亡过程,及其种内竞争和种间相互作用,是研究开发最早的一类生态模型之一.该类模型主要应用于分析植物种群之间相互作用.2)演替模型,主要模拟植物种类(动物与此相伴)在整个生态系统发展过程的变化,包括植被类型的转变和相关的生物地球化学循环过程的改变.可用于研究生物群落对气候变化的响应.3)生态系统模型,是把生态系统当作一个功能整体来模拟的一类模型,主要有以下3类(1)SVAT模型,主要模拟地表生态系统过程,以BATS、SiB、SiB2和LEAF为代表,多用于气候研究;(2)BGC模型,主要模拟3个关键循环碳,水和营养物质循环.常用的BGC模型有FOREST-BGC、BIOME-BGC、CENTURY、TEM、DOLY以及由它们衍生而来的整合模型组;(3)BG模型,模拟群落、生物群区中植物分布,比较具有代表性的 BGMs包括BIOME2和MAPSS,它们主要用于研究因气候变化而引起的生物分布的变迁.最后,结合我们的实际工作展望了生态模型在未来几年内的几个发展方向1)与基础学科相结合,比如把物候学引入生态模型研究中来,以寻求新的支撑点;2)与现代非线性理论相结合,重新评价模型的假设基础;3)与现代科学技术相结合,利用3S技术和计算机技术为模型的发展提供更强大的技术支持;4)在研究方法上,从还原论转向整体论,尽可能地把生态系统当作一个功能整体来模拟研究.     

ATTITUDES TOWARDS EUTHANASIA AND ASSISTED SUICIDE: A COMPARISON BETWEEN PSYCHIATRISTS AND OTHER PHYSICIANS

Euthanasia and physician assisted‐suicide are terms used to describe the process in which a doctor of a sick or disabled individual engages in an activity which directly or indirectly leads to their death. This behavior is engaged by the healthcare provider based on their humanistic desire to end suffering and pain. The psychiatrist's involvement may be requested in several distinct situations including evaluation of patient capacity when an appeal for euthanasia is requested on grounds of terminal somatic illness or when the patient is requesting euthanasia due to mental suffering. We compare attitudes of 49 psychiatrists towards euthanasia and assisted suicide with a group of 54 other physicians by means of a questionnaire describing different patients, who either requested physician‐assisted suicide or in whom euthanasia as a treatment option was considered, followed by a set of questions relating to euthanasia implementation. When controlled for religious practice, psychiatrists expressed more conservative views regarding euthanasia than did physicians from other medical specialties. Similarly female physicians and orthodox physicians indicated more conservative views. Differences may be due to factors inherent in subspecialty education. We suggest that in light of the unique complexity and context of patient euthanasia requests, based on their training and professional expertise psychiatrists are well suited to take a prominent role in evaluating such requests to die and making a decision as to the relative importance of competing variables.     

REFLECTION ON EUTHANASIA: WESTERN AND AFRICAN NTOMBA PERSPECTIVES ON THE DEATH OF A CHIEF

Largely, the concept of energy or vital force, as first analysed by Placide Tempels in Bantu Philosophy , permeates most African ontology systems, worldviews and life views. The Ntomba Chief is chosen because of his above average vital force. This puts him in the position of intermediary between the Supreme Being, the ancestors, and his subordinates. The waning of his energy is incompatible with his position because his energy is that of his tribe. When installed, he takes an oath that, when this happens, he has to accept mohilo , the 'hastening of death'. In the Chief's case, the hastening of death is not intended to relieve his pain, as it would be with other creatures. The Chief's dying a natural death would result in the loss of the entire community's vital force. Therefore, he has to be killed ritually to avoid that risk. That the Chief agrees to be killed – via a form of advanced directive – poses an ethical dilemma for a Western observer. From the Ntomba perspective, however, where the energy is being, and being is energy, it is the only way to preserve and protect the community's raison d'être .     

ETHICAL DEBATE OVER ORGAN DONATION IN THE CONTEXT OF BRAIN DEATH

This study investigated what information about brain death was available from Google searches for five major religions. A substantial body of supporting research examining online behaviors shows that information seekers use Google as their preferred search engine and usually limit their search to entries on the first page. For each of the five religions in this study, Google listings reveal ethical controversy about organ donation in the context of brain death. These results suggest that family members who go online to find information about organ donation in the context of brain death would find information about ethical controversy in the first page of Google listings. Organ procurement agencies claim that all major world religions approve of organ donation and do not address the ethical controversy about organ donation in the context of brain death that is readily available online.     

ON THE PARADIGM OF ALTRUISTIC SUICIDE IN THE UNICELLULAR WORLD

Altruistic suicide is best known in the context of programmed cell death (PCD) in multicellular individuals, which is understood as an adaptive process that contributes to the development and functionality of the organism. After the realization that PCD‐like processes can also be induced in single‐celled lineages, the paradigm of altruistic cell death has been extended to include these active cell death processes in unicellular organisms. Here, we critically evaluate the current conceptual framework and the experimental data used to support the notion of altruistic suicide in unicellular lineages, and propose new perspectives. We argue that importing the paradigm of altruistic cell death from multicellular organisms to explain active death in unicellular lineages has the potential to limit the types of questions we ask, thus biasing our understanding of the nature, origin, and maintenance of this trait. We also emphasize the need to distinguish between the benefits and the adaptive role of a trait. Lastly, we provide an alternative framework that allows for the possibility that active death in single‐celled organisms is a maladaptive trait maintained as a byproduct of selection on pro‐survival functions, but that could—under conditions in which kin/group selection can act—be co‐opted into an altruistic trait.     

THE GROWING PROBLEM OF SUICIDE

Informed as to the epidemiologic aspects of suicide and as to warning signs, physicians could, by appropriate action, prevent self-destruction in many cases.Not only ought each physician''s office be a suicide prevention station, but all physicians ought to act in concert to gather data, to carry out a program of public instruction and to enlist the aid of the press in an effort to reduce the ever-increasing rate of suicide.     

INTRODUCED MACROALGAE IN THE AUSTRALIAN REGION: CURRENT STATE OF KNOWLEDGE

Introductions of non‐native macroalgae and the subsequent displacement of native species are globally becoming more frequent. The algal genera Undaria, Sargassum, Caulerpa and Codium have been identified as being particularly invasive. An overview on the present knowledge on macroalgal introductions in the Australian region is presented and options for management are discussed, mostly using examples from studies on the introduced Japanese kelp, Undaria pinnatifida. Undaria pinnatifida was first detected in Tasmania, Australia in the early 1980's. Since then, its range has expanded despite eradication efforts. Long distance jumps appear to be the major mode of spread of U. pinnatifida in Tasmania. Studies are underway to distinguish the relative importance of spore dispersal, drift of adult plants and anthropogenic factors in spreading this invasive kelp. Although information on the real impacts of U. pinnatifida and other introduced macroalgae is sparse, the development of management and control strategies is of vital importance to prevent further spread and translocation of these “pest” species.