杨树人工林生态系统通量贡献区分析

采取通量源区模型FSAM(Flux Source Area Model)利用2009年北京大兴区杨树人工林生态系统碳水通量涡度相关观测资料,分析了不同大气条件下生态系统的通量贡献区分布特征。研究结果表明:(1)该站通量贡献区随大气稳定条件增强而增大。除326.25°—3.75°方向生长季不稳定条件下外,生长季的通量贡献区范围普遍大于非生长季的贡献区范围;(2)通量贡献区与观测高度、冠层高度、地表粗糙度、风向以及大气稳定度有关,当风速风频较大,大气不稳定时,湍流扩散作用强烈,贡献区范围较小;(3)该观测场在2009年以不稳定大气条件为主,通量信息主要来源于距离观测塔50—400 m范围,且69.3%的信息来源于通量塔偏北风与偏南风方向,其中42.56%的信息来自于偏南风方向;(4)随着大气稳定程度加强,通量来源最少区从塔偏西方转为偏东方,在大气稳定度条件和风向的共同作用下,生长季时主要通量贡献区在塔偏南方向,而非生长季时主要通量贡献区在塔偏北方向。     

Human Dignity as a Component of a Long-Lasting and Widespread Conceptual Construct

For some decades, the concept of human dignity has been widely discussed in bioethical literature. Some authors think that this concept is central to questions of respect for human beings, whereas others are very critical of it. It should be noted that, in these debates, dignity is one component of a long-lasting and widespread conceptual construct used to support a stance on the ethical question of the moral status of an action or being. This construct has been used from Modernity onward to condemn slavery and torture as violations of human dignity. In spelling it out, we can come to a better understanding of what “dignity” means and become aware that there exists a quite useful place for this notion in our ethical thought, albeit a modest one.     

Reckoning perverse outcomes of resource conservation policies using the Ecological Footprint

Spatially expanding economies threaten the status of basic natural resources. In particular, wildlife habitats rarely benefit. Apart from protected areas, political-economic decision-making is ill-prepared to accommodate wildlife habitats with standard valuation methods. In some cases habitat loss is an inadvertent outcome of resource conservation policies intended to lower resource consumption.We recognize the term resource conservation as multifaceted, with a range of meanings from protecting wildlife habitats to efficiently allocating and using materials and energy. Resource conservation policies that spur economic benefits may produce unwanted outcomes. This is partly because linkages between economic and conservation goals seem tangential. Moreover, relevant information is imperfect and predictive tools are limited. This is particularly true for land converting impacts, which are often addressed after the fact, not during policy formulation, and can lead to successive resource degradation.We argue for the need to calculate the positive and negative land converting impacts from resource conservation policies that may expand the economy. Using the Ecological Footprint (EF) approach, we tested for potentially perverse outcomes of an existing resource conservation policy. In doing so, we conceptually mapped linkages among economic sectors to their cumulative effects of converting land. We assume an inverse relationship between economic expansion and land conservation.A New York State energy efficiency incentive program was tested using recent data from all tracked economic sectors. The economic data were converted in a series of steps from dollar values to energy units, to carbon dioxide emissions, and ultimately expressed in hectares of net land conversion. A policy scenario was compared to a reference scenario (no resource conservation policy), and the results anticipate a net gain in conserving land (0.6% reduced conversion). We interpret this as a potentially proportional offset favoring wildlife habitat retention. Two sensitivity analyses demonstrated that the policy’s impact on conserving land depended on both the affected economy’s scale (tripling reduces the estimated benefit to 0.2%), and the level of economic expansion that followed (doubling leads to a net loss of wildlands).This novel use of the EF approach may serve as a model for a more general approach to assessing a broader class of policies. It may also hold promise toward developing tools that can better examine well-intentioned resource conservation policies with uncertain outcomes. Our hope is that work like this can lead to better sets of tools for examining critical ecological–economic linkages for improved policy design.     

Ecological Footprint: Informative and evolving – A response to van den Bergh and Grazi (2014)

Ecological Footprint accounting is used to track human demand on the Earth's biological resource flows, and compares that demand with the Earth's capacity to generate these flows. It is an evolving tool which has undergone many improvements alongside advancements in science and in response to critical review. Here we respond to van den Bergh and Grazi's recent points of criticism toward Ecological Footprint accounting. While the authors suggest that new criticism is accumulating, the main issues appear to be the same. We suggest that the majority of the criticism is derived from the misconception that the Ecological Footprint measures land “use,” which cannot exceed land availability. In response to these criticisms, we aim here to summarize and further clarify the major points of debate and confusion and allow readers to determine the relevance of these issues. We conclude that much of the prior discussion and many of the points repeated here reflect a divergence in general philosophical or semantic perspectives.     

“Whoever decides for you without you,s/he is against you!”: immigrant activism and the role of the Left in political racialization

Much of the migration literature neglects the questions of why and how “native” allies obstruct activism by immigrants and ethnic minorities. Left-wing organizations in particular are often assumed to be supportive of inclusion, and little research exists on the ways they have prevented the migrant population from having a voice in the political arena and from taking part in society as equals. Drawing on the critical theory literature, I introduce the concept of political racialization. This concept refers to mechanisms whereby political actors, in order to legitimize their work on immigration, have partially included immigrants in the political sphere, but in a relationship of “ethnic” or “racial” subordination. Through the analysis of 57 in-depth interviews with immigrant activists, I show how political racialization works within the Italian Left and how it contributes to marginalize the migrant population. I further explain how immigrant activists have challenged political racialization through their activism.     

Marine metapopulations: a useful concept?

We discuss the potential and limitations of the metapopulation concept in marine ecology. The usefulness of the concept in terrestrial ecology is neither based on its simplicity or generality nor on overwhelming empirical evidence. The usefulness is in the questions which are asked when the metapopulation concept is applied. These questions address spatial phenomena and processes on different spatial scales. They help in acknowledging that every population, be it terrestrial or marine, has a spatial organization. Understanding this spatial organization is also important for tackling specific applied problems, i.e. to avoid overexploitation of living marine resources or for configuring marine reserves. The 'openness' of coastal populations, whose larvae enter larval pools or which are holoplanktonic, is no reason for not asking the questions implied by the metapopulation concept. For marine ecology, the real problem is to delineate populations, which then may possibly correspond to the 'local populations' of metapopulations. Thus, the answer to the question in the title of this paper, whether 'marine metapopulation' is a useful concept, is 'yes', if the concept is considered a working hypotheses, if the concept is explicitly defined, and if the questions linked to the concept are clearly stated. Even if it eventually transpires that only very few marine metapopulations actually exist, marine ecology would still have gained some important new insights. Electronic Publication     

Children and biobanks: a review of the ethical and legal discussion

The use of tissue samples from children is vital to genetic research. Collections of such tissue, in so-called biobanks, can take the form of large-scale prospective cohort studies or disease-specific studies using tissue of children with that specific disease. Collections of samples gathered in a diagnostics context, such as blood spot cards, can also be used for genetic research. Research on stored tissue samples from children poses ethical questions that are different from those posed by the use of samples from adults. Also, the ethical questions raised by the participation of children in biobanks are not analogous to those raised by the participation of children in clinical trials. In this review we first give an overview of the international ethical guidelines and legal regulations concerning biobanking and minors. Next, we review the different themes that occur in the ethical literature on this subject. Specifically we focus on questions of risk and benefit, consent and assent and the return of individual results. We also discuss the concept of solidarity, which is a relatively new concept in the context of children and biomedical research. To conclude, we discuss the gaps and questions raised by the review.     

Current perspectives and challenges in understanding the role of nitrite as an integral player in nitric oxide biology and therapy

Beyond an inert oxidation product of nitric oxide (NO) metabolism, current thinking posits a key role for nitrite as a mediator of NO signaling, especially during hypoxia. This concept has been discussed in the context of nitrite serving a role as an endogenous modulator of NO homeostasis, but also from a novel clinical perspective whereby nitrite therapy may replenish NO signaling and prevent ischemic tissue injury. Indeed, the relatively rapid translation of studies delineating mechanisms of action to ongoing and planned clinical trials has been critical in fuelling interest in nitrite biology, and several excellent reviews have been written on this topic. In this article we limit our discussions to current concepts and what we feel are questions that remain unanswered within the paradigm of nitrite being a mediator of NO biology.     

Critical and timely review of the concept of gastric cytoprotection

Gastric cytoprotection is a concept or phenomenon, and not a single magic mechanism of action of unusual compounds. It refers to prevention of acute hemorrhagic erosions where the superficial epithelial cells are not directly protected but are rapidly replaced by restitution in microvascular injury in subepithelial capillaries is prevented or diminished and blood flow is maintained. This gastroprotection achieved by prostaglandins (PG), sulfhydryls (SH) and non-SH antioxidants is thus real but relative by target, mechanisms and in time. PG and SH are the only two chemical entities with both pharmacologic and biochemical relevance, i. e., endogenous concentrations of PG and SH derivatives may be measured biochemically and correlated with the degree of gastroprotection. Despite differences in the chemical mechanisms of action (e. g., SH unlike PG scavenge free radicals and may directly influence SH-sensitive receptors, enzymes and membrane permeability), the structural and functional targets for both groups of compounds are essentially the same: prevention or reduction of microvascular injury in subepithelial capillaries, maintenance of blood flow which allows the energy-requiring rapid epithelial restitution to repair the superficial epithelial defect. This reductionist, critical and mechanistic overview highlights the recent developments and the persisting problems in study design, definitions and interpretation of results as well as some critical questions related to the concept of gastric cytoprotection.     

Evaluating environmental sustainability with the Waste Absorption Footprint (WAF): An application in the Taihu Lake Basin,China

The ecological footprint (EF) is an accepted worldwide method for the evaluation of environmental sustainability. However, its utility is limited by the existence of a series of shortcomings in the methodology such as the only-partial inclusion of human generated wastes. To improve the ability of the footprint method to evaluate environmental sustainability, a new footprint-based indicator – the ‘Waste Absorption Footprint’ (WAF) – has been proposed. The purpose of this paper is to test this methodological approach by evaluating the sustainability of the water environment in the Taihu Lake Basin, in densely populated eastern China. Applying the WAF method indicates that anthropogenic discharges of wastes have imposed an absorption pressure on the local water system such that the local water environment is increasingly unsustainable. Furthermore, nitrogen and phosphorus are identified as more critical wastes than organic substances, while domestic discharges are shown to be more important sources compared with those from industry and agriculture, which therefore should be the focus of environmental management and pollution control initiatives. It is demonstrated that the WAF method can provide a wealth of information that can be used for reference by local water environmental management authorities.     

Innateness and the Sciences

The concept of innateness is a part of folk wisdom but is also used by biologists and cognitive scientists. This concept has a legitimate role to play in science only if the colloquial usage relates to a coherent body of evidence. We examine many different candidates for the post of scientific successor of the folk concept of innateness. We argue that none of these candidates is entirely satisfactory. Some of the candidates are more interesting and useful than others, but the interesting candidates are not equivalent to each other and the empirical and evidential relations between them are far from clear. Researchers have treated the various scientific notions that capture some aspect of the folk concept of innateness as equivalent to each other or at least as tracking properties that are strongly correlated with each other. But whether these correlations exist is an empirical issue. This empirical issue has not been thoroughly investigated because in the attempt to create a bridge between the folk view and their theories, researchers have often assumed that the properties must somehow cluster. Rather than making further attempts to import the folk concept of innateness into the sciences, efforts should now be made to focus on the empirical questions raised by the debates and pave the way to a better way of studying the development of living organisms. Such empirical questions must be answered before it can be decided whether a good scientific successor – in the form of a concept that refers to a collection of biologically significant properties that tend to co-occur – can be identified or whether the concept of innateness deserves no place in science.     

The implications of palaeontological evidence for theories of ecological communities and species richness

Abstract Palaeontological evidence raises several questions that relate to current explanations of ecological communities, to the classification of communities and to interpretations of species richness. The first question relates to the stability of species detected in the fossil record. Coupled with that is the issue of incidental association of species on the same trophic level through differential effects of climatic change on the different species. Such observations are seen to support the ‘individualistic’ concept of communities. Recent statements about this concept leave unresolved questions about the acquisition of adaptation, and about the place of adaptation theory in theories of ecological communities and interpretations of ‘regional species richness’. At issue is whether there is justification for continuing to classify communities as a basis for understanding them. There is good reason to reject this approach for one in which questions about communities and ‘local’ and ‘regional’ species richness are replaced by more specific and basic questions about the relationship between adaptation, distribution and abundance, and ecological interactions. Some recent efforts to incorporate species theory into community theory fail because their basis remains the flawed concept of ‘local community’.     

Cell signaling, beyond cytosolic calcium in eukaryotes

Calcium functions as a secondary messenger within the cytosols of eukaryotes. This serves as a reference point to evaluate three related questions:Exploration of these three interrelated questions indicates the importance of more sensitive techniques and of a refined concept of information transfer and transduction. 1. Calcium, as well as cyclic AMP, also functions as a paracrine messenger; how specific and extensive is this use? 2. Calcium binding proteins and calcium extrusion mechanisms have been identified in prokaryotes; does it function as a messenger? 3. The concentrations of other divalent cations, especially zinc and magnesium, are well regulated and perturbations have specific physiological impacts; are these divalents involved in information transfer? Exploration of these three interrelated questions indicates the importance of more sensitive techniques and of a refined concept of information transfer and transduction.     

Ecological Footprint: Refining the carbon Footprint calculation

Within the Ecological Footprint methodology, the carbon Footprint component is defined as the regenerative forest capacity required to sequester the anthropogenic carbon dioxide emissions that is not absorbed by oceans. A key parameter of the carbon Footprint is the Average Forest Carbon Sequestration (AFCS), which is calculated from the net carbon sequestration capacity of forests ecosystems.The aim of this paper is to increase the clarity and transparency of the Ecological Footprint by reviewing the rationale and methodology behind the carbon Footprint component, and updating a key factor in its calculation, the AFCS. Multiple calculation options have been set to capture different rates of carbon sequestration depending on the degree of human management of three types of forest considered (primary forests, other naturally regenerated forests and planted forests). Carbon emissions related to forest wildfires and soil as well as harvested wood product have been included for the first time in this update of the AFCS calculation. Overall, a AFCS value range of 0.73 ± 0.37 t C ha⁻¹ yr⁻¹ has been identified. The resulting carbon Footprint and Ecological Footprint values have then been evaluated based on this value range. Results confirm that human demand for ecosystem services is beyond the biosphere's natural capacity to provide them.     

The debate about death: an imperishable discussion?

In this concise review we discuss some of the complex edges of the concept of death that arose after the notorious advances in science and medicine over the last 50 years, in which the classical cardio-pulmonary criteria have led to the neurological criteria of death. New complicated questions like the definition of death and the operational criteria for diagnosing it have arisen and we think that they are far from being adequately and satisfactorily solved. A number of important issues--like the reliability and differences between cardio-pulmonary versus brain based criteria of death, if death is an event or a process, the meaning of integration and irreversibility--have not yet received sufficient attention. Here we have approached the death problem from two (biological) complex system perspectives: the organism level and the cellular-molecular level. We also discuss issues from a third systemic approach, that is, the entire society, thus involving legal, religious, bioethical and political aspects of death. Our aim is to integrate new perspectives in order to promote further discussion on these critical yet frequently neglected issues.     

Measuring ethnicity: challenges and opportunities for survey research

Measuring ethnic identity in social surveys has traditionally been problematic, often using a single question and allowing the respondent to choose one category from a pre-defined list. In this paper we discuss the rationale for and limitations of measuring a complex and multi-dimensional concept with a simple, uni-dimensional question. We propose that operationalizing ethnicity as multi-dimensional requires multiple questions to capture the complexity of the concept. Giving researchers a number of different measures enables them to focus on the dimensions of interest to them, and has the potential to open up the rich resources of theoretically robust survey research to researchers from a range of disciplines concerned with questions of ethnic identification.     

Post-racial futures: imagining post-racialist anti-racism(s)

Abstract

Can the theoretical insights of post-racialism contribute to the development of a progressive anti-racism? Drawing on interviews with anti-racist organizations in London, this article explores the translation of the theoretical insights of post-racialism into anti-racist praxis. Theoretically informed and empirically engaged, this article argues that post-racialism faces its own set of paradoxes and practical dilemmas complicating the process of deriving post-racialist practice(s) from post-racialist theory. The article concludes that, in spite of the challenges, the powerful questions that post-racialism raises create a much needed ethico-political space for critical reflection on the concept and category of race. Ultimately, post-racialist insights may refine understandings of the discriminatory practices performed in the name of race and point towards a methodological approach of working with and against race in anti-racism.     

Intermediate Moral Respect and Proportionality Reasoning

In a recent article in this journal Jonathan Pugh critiques the idea of intermediate ‘moral respect’ which some say is owed to embryos. This concept is inherent within the ‘principle of proportionality’, the principle that destructive research on embryos is permissable only if the research serves an important purpose. Pugh poses two specific questions to proponents of the idea of intermediate moral respect. This article argues that while the questions posed by Pugh are certainly pertinent to the debate, the hypothetical responses he suggests to these questions do not quite get to the core of what is troublesome about the concept. The article suggests alternative responses to Pugh's questions in order to focus attention on more fundamental problems facing the idea of intermediate moral respect, while also pointing to how the intermediate moral respect proponent might best develop these responses. It goes on to argue that these hypothetical responses fail to answer convincingly the questions posed. More specifically, this article challenges two possible justifications for the distinct idea of intermediate moral respect, namely the argument from potentiality (the argument raised by Pugh) and an argument from the proportionality of fundamental moral status (not considered by Pugh). The article also raises a dilemma inherent in the application of the principle of proportionality to cases involving beings to which intermediate moral respect is owed even where it is allowed, ex hypothesi, that both the category of intermediate moral respect and the general proportionality reasoning underpinning the principle of proportionality are basically cogent. This article thus develops and adds to the challenge laid down by Pugh to proponents of the idea of intermediate moral respect.