丘间低地生态过程研究进展

丘间低地是《国际保护日程》所列的重点保护生境,近50年来一直受到生态恢复和生物多样性保护专家的关注.本文从丘间低地植被过程、土壤发育过程、水文过程、尺度对丘间低地生态过程的影响,以及丘间低地生物多样性保护及生态恢复等方面概述了丘间低地生态过程的主要研究内容、趋势和进展.近十几年,丘间低地生态过程研究体现了从单尺度到多尺度或跨尺度、从表征描述到机制探讨、从野外调查到控制试验过渡的趋势.然而,丘间低地生态过程的尺度性仍有待进一步探讨,丘间低地景观格局对生态过程的影响尚不清楚.今后,半干旱内陆地区丘间低地生态过程的研究将趋于增多,干扰生态学和景观生态学的理论和方法将会在丘间低地研究中得到更多应用.     

生态水文过程研究进展

生态水文学是研究生态格局和生态过程变化水文学机制的科学。它的一个重要研究方向是在不同时空尺度上和一系列环境条件下探讨生态水文过程。生态水文过程是指水文过程与生物动力过程之间的功能关系 ,它包括生态水文物理过程、生态水文化学过程及其生态效应。在探讨以上基本概念和总结生态水文过程研究特点的基础上 ,着重探讨生态水文物理过程、生态水文化学过程及其生态效应等生态水文过程核心内容的研究进展 ,并简要分析了生态水文过程研究中存在的主要问题和未来的研究热点。     

Implicit and explicit processes in social cognition

In this review we consider research on social cognition in which implicit processes can be compared and contrasted with explicit, conscious processes. In each case, their function is distinct, sometimes complementary and sometimes oppositional. We argue that implicit processes in social interaction are automatic and are often opposed to conscious strategies. While we are aware of explicit processes in social interaction, we cannot always use them to override implicit processes. Many studies show that implicit processes facilitate the sharing of knowledge, feelings, and actions, and hence, perhaps surprisingly, serve altruism rather than selfishness. On the other hand, higher-level conscious processes are as likely to be selfish as prosocial.     

河口最大浑浊带浮游植物生态动力过程研究进展

通过对近十几年来河口最大浑浊带浮游植物生态动力过程研究的报道进行综述,阐明该方面研究的最新进展。研究结果表明,河口最大浑浊带的湍流混合过程增大了浮游植物细胞光合作用的机会;重力环流致使浮游植物及其光合作用所需的物质有较长时间的停留;再悬浮过程使微型底栖藻类对最大浑浊带水体中叶绿素产生明显贡献;锋面强烈的辐合聚集作用则可使浮游植物在锋面附近出现高值现象。最后对河口最大浑浊带浮游植物生态动力过程的继续研究提出了几点看法。     

Rosette glands in the gills of the grass shrimp Palaemonetes pugio. II. Premolt ductule reformation: Replacement of ciliary processes by cytoplasmic processes in relation to gland maturation

The events associated with premolt reformation of the cuticularized ductule in the underdeveloped (immature) branchial rosette glands, which are common in the gills of small (14–18 mm, total length) grass shrimp, are described and contrasted with the events of ductule reformation in the fully developed (mature) resette glands most common in larger shrimp. In immature rosette glands, two ciliary processes emerge from each of the component secretory cells and ascend into the basal luminal region of the old ductule. Subsequently a new ductule is formed around the old ductule, and the ciliary processes disappear, either because of degeneration or retraction. The transitory ciliary processes appear to prevent the old ductule from collapsing during the formation of a new ductule. Such transitory ciliary processes, however, are not found in association with premolt ductule reformation in the mature rosette glands; in their place are seen a number of microvilli-like cytoplasmic processes, which emanate from the apices of the secretory cells and from the channels of the central cell. These cytoplasmic processes in mature glands, like the ciliary processes in immature glands, are transitory and appear to prevent the collapse of the old ductule. Cytoplasmic processes comparable to those in mature glands, but relatively few in number and originating only from the secretory cells, are seen together with ciliary processes in some immature glands. The relative abundance of cytoplasmic processes in the mature glands, coupled with the observation that transitory ciliary processes occur in immature glands but not in mature glands, suggests that, during glandular maturation, transitory ciliary processes are replaced by transitory cytoplasmic processes.     

Interrelated mechanisms in reward and learning

This brief review is focused on recent work in our laboratory, in which we assayed nicotine-induced neurotransmitter changes, comparing it to changes induced by other compounds and examined the receptor systems and their interactions that mediate the changes. The primary aim of our studies is to examine the role of neurotransmitter changes in reward and learning processes. We find that these processes are interlinked and interact in that reward-addiction mechanisms include processes of learning and learning-memory mechanisms include processes of reward. In spite being interlinked, the two processes have different functions and distinct properties and our long-term aim is to identify factors that control these processes and the differences among the processes. Here, we discuss reward processes, which we define as changes examined after administration of nicotine, cocaine or food, each of which induces changes in neurotransmitter levels and functions in cognitive areas as well as in reward areas. The changes are regionally heterogeneous and are drug or stimulus specific. They include changes in the transmitters assayed (catecholamines, amino acids, and acetylcholine) and also in their metabolites, hence, in addition to release, uptake and metabolism are involved. Many receptors modulate the response with direct and indirect effects. The involvement of many transmitters, receptors and their interactions and the stimulus specificity of the response indicated that each function, reward and learning represents the involvement of different pattern of changes with a different stimulus, therefore, many different learning and many different reward processes are active, which allow stimulus specific responses. The complex pattern of reward-induced changes in neurotransmitters is only a part of the multiple changes observed, but one which has a crucial and controlling function.     

Redox processes in biological systems

General principles of organization and distinctive features of the redox processes of biological systems are discussed. We paid special attention to the most examined parts of redox biology. As one of the approaches to the generalization of accumulated knowledge about redox processes, the so-called redox hypothesis of oxidative stress was examined. Extrapolation of this hypothesis on the processes taking place in plant cells, formulated on the basis of thiol-disulfide metabolism of animal cells, may help to systematize the available knowledge about redox processes in plants.     

Ecological processes: A key element in strategies for nature conservation

Summary A common approach to nature conservation is to identify and protect natural ‘assets’ such as ecosystems and threatened species. While such actions are essential, protection of assets will not be effective unless the ecological processes that sustain them are maintained. Here, we consider the role of ecological processes and the complementary perspective for conservation arising from an emphasis on process. Many kinds of ecological processes sustain biodiversity: including climatic processes, primary productivity, hydrological processes, formation of biophysical habitats, interactions between species, movements of organisms and natural disturbance regimes. Anthropogenic threats to conservation exert their influence by modifying or disrupting these processes. Such threats extend across tenures, they frequently occur offsite, they commonly induce non‐linear responses, changes may be irreversible and the full consequences may not be experienced for lengthy periods. While many managers acknowledge these considerations in principle, there is much scope for greater recognition of ecological processes in nature conservation and greater emphasis on long time‐frames and large spatial scales in conservation planning. Practical measures that promote ecological processes include: monitoring to determine the trajectory and rate of processes; incorporating surrogates for processes in conservation and restoration projects; specific interventions to manipulate and restore processes; and planning for the ecological future before options are foreclosed. The long‐term conservation of biodiversity and the well‐being of human society depend upon both the protection of natural assets and maintaining the integrity of the ecological processes that sustain them.     

Deterministic diversity changes in freshwater phytoplankton in the Yunnan–Guizhou Plateau lakes in China

Diversity measures reflect different aspects of a community, which are determined by different ecological processes. However, information is still limited on the ecological processes that are represented by different measures of species diversity. In this study, the primary driving factors for richness and diversity indices were tested. The possible ecological processes represented by each index were analyzed. First, the type of ecological process that governed the phytoplankton community in the Yunnan–Guizhou Plateau lakes, either deterministic or stochastic, was identified by Caswell's neutral model. The results indicate that a deterministic process governs the phytoplankton community. Second, the driving factors of richness and diversity indices were screened with mixed models. The results suggest that the variation of phytoplankton richness in different lakes or sites was primarily related to bottom-up factors. The variations in evenness and other measures based on the relative abundance were driven by both top-down and bottom-up factors, such as zooplankton biomass, and pH and mean light, respectively. Finally, although the different measures of diversity may respond to specific bottom-up or top-down processes, the responses to the two processes were not independent of each other. These findings will increase our understanding of the relationships between ecological processes and diversity measures for freshwater phytoplankton.     

Light and electron microscopic localization of a monoclonal antibody in neurons in situ in the head region of Hydra

A mouse monoclonal antibody to Hydra attenuata was used to demonstrate immunoreactive product in neurons in situ, in both whole mount and sectioned hypostomes and tentacles of H. oligactis and H. littoralis. Immunoreactive cells were concentrated around the mouth and scattered along the length of the tentacles. In the hypostome, nerve cells sent one or more processes orally and the others aborally but the processes were more distinctly stained in H. oligactis. A thin strand of five to six perihypostomal neurons was present close to the hypostome-tentacle junction. In the tentacles, neurons with long processes contacted up to five different batteries of nematocysts. Neural processes were associated with nematocyst batteries in three ways: 1) forming a perikaryal loop to encircle a centrally located stenotele, 2) branching at a distance from the perikaryon to contact a variety of nematocysts, and 3) terminal branching by one or more neurons with contacts on one to several nematocysts within a battery. Immunocytochemical localization of neurons in Hydra by light microscopy was correlated for the first time with electron microscopy. Peroxidase-antiperoxidase (PAP)-positive sensory cells were concentrated around the mouth opening. PAP-positive ganglion cells were predominant in the tentacles. Sensory cells were elongate or spindle-shaped (unipolar), triangular with two oppositely directed processes (bipolar), and multipolar (tripolar or tetrapolar) with one of the processes extending to the epidermal surface. Ganglion cells were either unipolar or bipolar or multipolar, with neurites paralleling the mesoglea and occasionally having processes abut on it.     

湖泊微生物反硝化过程及速率研究进展

湖泊中微生物介导的反硝化过程对于区域乃至全球的气候环境变化有着深远的影响。因此,研究湖泊微生物反硝化过程及速率有助于我们深刻理解湖泊氮元素生物地球化学循环规律,全面认识湖泊生境对全球氮循环的贡献。本文综述了湖泊生境中反硝化过程(包括典型的反硝化过程及与其他物质循环耦合的反硝化过程,如与有机氮耦合的共反硝化作用、与碳循环耦合的硝酸盐/亚硝酸盐依赖型厌氧甲烷氧化、与铁循环耦合的硝酸盐依赖型铁氧化、与硫循环耦合的硝酸盐还原硫氧化)的速率、驱动微生物及其影响因素。最后对湖泊反硝化过程研究现状和未来发展方向提出总结与展望。     

Rhythmic processes in early embryogenesis timed by cell division

he data on rhythmic processes in early embryogenesis coinciding with cell divisions are considered. Possible mechanisms which determine the rhythm frequency and are its motive power are discussed, as well as the role of individual rhythmic processes in the regulation of consecutive cell cycle events. A suggestion is put forward that these rhythmic processes are transformed during subsequent development in circum-hour rhythms of some biochemical, physiological and biophysical processes discovered in the cells and organs of adult organism.     

黄土高原生态水文过程研究进展

以黄土高原水文过程为主线,围绕水资源短缺、水量分布不均衡、水文过程的复杂性和非稳态等特性,梳理了黄土高原水文过程的主要现状及研究进展,包括水资源分布、水量平衡和水文循环等过程;融合生态水文尺度效应,从土壤、微生物、植物冠层、坡面、流域和景观等方面归纳和总结了黄土高原生态水文过程;针对该区生态水文过程的时空异质性,提出未来更需要通过多学科交叉与融合手段,加强宏观与微观过程的集成与联网研究;采用多尺度、多要素、多时空的综合观测与模拟手段,定量重要生态功能区水分承载力及生态阈值;从生态学和水文学方面揭示不同时空尺度下水分转移与分配特征;为解决黄土高原水资源的宏观调控与最优分配模式提供理论基础。     

Reconstructing feedback representations in the ventral visual pathway with a generative adversarial autoencoder

While vision evokes a dense network of feedforward and feedback neural processes in the brain, visual processes are primarily modeled with feedforward hierarchical neural networks, leaving the computational role of feedback processes poorly understood. Here, we developed a generative autoencoder neural network model and adversarially trained it on a categorically diverse data set of images. We hypothesized that the feedback processes in the ventral visual pathway can be represented by reconstruction of the visual information performed by the generative model. We compared representational similarity of the activity patterns in the proposed model with temporal (magnetoencephalography) and spatial (functional magnetic resonance imaging) visual brain responses. The proposed generative model identified two segregated neural dynamics in the visual brain. A temporal hierarchy of processes transforming low level visual information into high level semantics in the feedforward sweep, and a temporally later dynamics of inverse processes reconstructing low level visual information from a high level latent representation in the feedback sweep. Our results append to previous studies on neural feedback processes by presenting a new insight into the algorithmic function and the information carried by the feedback processes in the ventral visual pathway.     

Spatial heterogeneity and function of voltage- and ligand-gated ion channels in retinal amacrine neurons.

The spatial distribution of ion channels within amacrine cells of the tiger salamander retina was studied using patch recording in the retinal slice preparation. By focally puffing kainate, GABA and glycine at amacrine cell processes in the inner plexiform layer, it was determined that the cell's glutamate receptors were located in a confined region of the processes near the soma, while glycine and GABA receptors were located throughout the processes. Likewise, similar techniques in conjunction with voltage steps demonstrated that voltage-gated sodium channels were located throughout the cell and were shown to generate sodium-dependent spikes, while only the processes contained voltage-gated calcium channels. These results suggest that this form of transient amacrine cell collects its excitatory synaptic inputs in a region confined to a central annular region near the soma, that the signal is actively propagated throughout its processes by voltage-gated sodium channels and that calcium-dependent neurotransmitter release of glycine from this neuron can occur throughout its processes. Thus, excitatory signals are collected in the processes near the soma, inhibitory signals throughout the processes and excitation is probably propagated throughout the processes of the amacrine cell.     

Molecular genetics and epigenetics in the morphogenesis mechanisms

The progress of molecular genetics principally changed the views on heredity and, in the long run, wrecked the synthetic theory of evolution, designed for the microevolutionary processes in populations only. Molecular genetics as a whole is sufficient for analyzing evolutionary processes in viruses and prokaryotes. But in multicellular organisms, with the advent of more complicated morphogenesis, epigenetic processes took effect. Appealing exclusively to the integrity of the organism in ontogeny is insufficient for the understanding of these processes; further studies of the molecular basis for this integrity are required. The discovery of homeobox genes was an important step on this path. The theory of evolution should include not only the molecular processes but also the laws of ecosystem and biosphere processes, which study requires handling many problems of ecology, parasitology, palaeontology, and geology. All these fields together comprise an enormous area of knowledge for which the development of a unified theory is scarcely possible.     

Disentangling spatio‐temporal processes in a hierarchical system: a case study in fisheries discards

In the last decade, various spatial and temporal methodologies were developed to investigate the processes that drive ecological and evolutionary patterns. However, these methods frequently fail to acknowledge that the observed patterns result from the overlap of different underlying processes. In order to understand how the patterns are formed, we must have recourse to methods that allow us to disentangle these simultaneous processes. Here we develop a hierarchical spatial predictive process (PP) combined with a separable temporal PP to disentangle and describe those overlapping processes in one very frequent setting in ecology and evolution: multilevel spatio‐temporally indexed data. We present our methodology through a case study of fisheries discards and investigate for example whether the inclusion of the hierarchical structure and the temporal processes of the system alter the observed spatial patterns. Recently it is recognized that understanding the processes driving discards is essential to sustainably manage and conserve marine resources. The results show that consideration of multiple underlying processes dramatically changes the pattern and characteristics of the discards hot‐ and coldspots. In the Irish Sea, the inclusion of the hierarchical structure of the system leads to the reduction of the hot‐ and coldspots. Simultaneously, our model identifies key bi‐annual fluctuations in the temporal process which, together with the variance associated at the level of individual fishing trips in the hierarchical structure of the data explained most of the variance driving discards. Whether the hierarchical, spatial and temporal processes are considered together or not can profoundly alter our understanding of what constitutes an appropriate mitigation measure. Misidentification of hotspots can culminate in inappropriate mitigation practices which can sometimes be irreversible. As the proposed method offers a unified approach for understanding the processes that drive observed patterns, many areas in ecology such as conservation and epidemiological studies can benefit from its use, increasing the effectiveness of management plans.     

Nothing in glycobiology makes sense, except in the light of evolution

The remarkable structural diversity of glycans in nature, and their roles in cellular processes, host-pathogen interactions, biological diversity and speciation can be explained by evolutionary processes.     

Macroalgae in biofuel production

The conversion processes of macroalgae for biofuels can be divided into thermochemical (dry) and microbiological (wet) processes. The chemical composition of macroalgae together with the pre‐treatment method, conversion conditions, and the characteristics of the microbes involved (wet processes) determine the yield and the properties of the biofuel produced. Macroalgae are often rich in carbohydrates, and therefore well suited for biogas, biobutanol and bioethanol productions. The content of triacylglycerols (TAGs) is the best indicator for the suitability of the alga for biodiesel production. TAGs have a high conversion rate to biodiesel, high percentage of fatty acids, and they lack phosphorus, sulfur and nitrogen. Macroalgae can have high metal concentrations, which can have an impact on conversion processes: metals may inhibit or catalyse the processes. High sulfur (especially in green algae) and nitrogen contents are also characteristic to macroalgae, and may be problematic in the production of biogas (NH₃‐toxicity) and the use of the oil and biodiesel (high concentrations of H₂S and NO_x‐compounds). Macroalgae have proven to be suitable material for conversion processes, but further optimization of the processes is needed. At present, macroalgae are not economically, or in many cases not even environmentally, sustainable material when the whole production chain is considered. In this review we summarize information on the chemical composition of macroalgae in a prospect of biofuel production, and the current situation in the field of macroalgal‐based biofuel production.