精神疲劳状态下脑组织血氧饱和度的近红外光谱分析

目的:研究精神疲劳状态下脑组织血氧饱和度的变化规律。方法:从某军校随机抽取25名被试,采用模拟飞行任务负荷构建精神疲劳模型,采用NASA-TLX量表评价模型。实验全程使用近红外光谱技术对被试脑组织血氧饱和度进行实时监测;实验前后分别对被试的作业绩效水平进行评估。结果:任务后NASA-TLX量表评分明显高于任务前(P0.01);任务前后作业绩效发生变化,反应能力测试的正确率下降(P0.01),错误率上升(P0.01);任务负荷后脑组织血氧饱和度相对于静息状态升高(P0.05)。结论:精神疲劳状态会影响被试的作业绩效。疲劳后脑组织血氧饱和度水平受被试动机以及代偿机制的影响高于静息水平。     

Income deprivation and mental well-being: The role of non-cognitive skills

We show that the positive relation between income deprivation and mental health is affected by an individual's non-cognitive skills. Income deprivation is operationalized as the Yitzhaki index, i.e., as a function of the sum of income differences between an individual and others in her reference group who are more affluent. Non-cognitive skills are extracted from a Locus of Control questionnaire and the Big Five Inventory, a self-report measurement of an individual in regard to five aspects of personality: conscientiousness, neuroticism, extraversion, agreeableness and open-mindedness. The results, based on the 2002–2010 waves of the German Socio-Economic Panel dataset (SOEP), show that deprivation is negative and significantly related with mental health. However, neurotic individuals are more deprivation-sensitive than are others. Compared to the mean effect, a one standard deviation rise in neuroticism is associated with a deprivation effect that is 36.6% and 51.9% larger among men and women, respectively. Although to a lesser extent, extraverted men and conscientious women are also found to be more deprivation-sensitive than are others, the corresponding figures being 31.1% and 45.9%, respectively. These findings suggest that personality differences should be taken into account in the design of policies, practices and initiatives aimed at alleviating the well-being costs of income deprivation.     

Heteroskedasticity as a leading indicator of desertification in spatially explicit data

Regime shifts are abrupt transitions between alternate ecosystem states including desertification in arid regions due to drought or overgrazing. Regime shifts may be preceded by statistical anomalies such as increased autocorrelation, indicating declining resilience and warning of an impending shift. Tests for conditional heteroskedasticity, a type of clustered variance, have proven powerful leading indicators for regime shifts in time series data, but an analogous indicator for spatial data has not been evaluated. A spatial analog for conditional heteroskedasticity might be especially useful in arid environments where spatial interactions are critical in structuring ecosystem pattern and process. We tested the efficacy of a test for spatial heteroskedasticity as a leading indicator of regime shifts with simulated data from spatially extended vegetation models with regular and scale‐free patterning. These models simulate shifts from extensive vegetative cover to bare, desert‐like conditions. The magnitude of spatial heteroskedasticity increased consistently as the modeled systems approached a regime shift from vegetated to desert state. Relative spatial autocorrelation, spatial heteroskedasticity increased earlier and more consistently. We conclude that tests for spatial heteroskedasticity can contribute to the growing toolbox of early warning indicators for regime shifts analyzed with spatially explicit data.     

Epistasis effects of COMT and MTHFR on inter-individual differences in mental health: Under the inverted U-shaped prefrontal dopamine model

Higher cognitive performance, maintenance of mental health and psychological well-being require adequate prefrontal cortex (PFC) function. “Inverted U-shaped” dopamine model indicates optimal PFC dopamine level is important to attain its function while high or low levels have adverse effects. Catechol-O-methyltransferase (COMT) and methylenetetrahydrofolate reductase (MTHFR) may be involved in this complex non-linear PFC dopamine regulation. We addressed whether genetic variation reflecting COMT and MTHFR activities can explain the inter-individual mental health differences in healthy Japanese men (n = 188). The mental health was measured by Mental Health Inventory (MHI)-5 score. The rs4633–rs4818–rs4680 haplotypes were used to represent the multilevel COMT activities, while for MTHFR, the functional single polymorphism, rs1801133 (C677T), was used. We examined the effectiveness of haplotype-based association analysis of COMT on mental health together with studying its interaction with MTHFR-C677T. As a result, the relation between activity-ranked COMT genotype and MHI-5 score showed a tendency to fit into an “inverted U-shaped” quadratic curve (P = 0.054). This curvilinear correlation was significant in the subjects with MTHFR-CC (P < 0.001), but not with MTHFR T-allele carriers (P = 0.793). Our pilot study implies a potential influence of COMT and MTHFR genotypic combination on normal variation of mental health.     

Factors Affecting Tropical Tree Damage and Survival after Catastrophic Wind Disturbance

The structure and dynamics of cyclone‐prone tropical forests are driven in part by variation in tree species resistance to and survival after wind‐induced structural damage. We determined the factors associated with tree damage and 3‐yr survival following Category 5 Cyclone Olaf on the Polynesian island of Ta'u, American Samoa. Despite sustaining a high rate of severe damage (34.6% of all trees snapped, 23.0% uprooted), system resilience was high with 74.3 percent stem survival overall and an annual mortality rate of 7.9 percent compared with 2.1 percent in nearby undisturbed late successional forest. Three‐yr survival rate of trees sustaining severe damage was 63.1 percent, compared to about 89 percent for trees sustaining only branch loss or defoliation. Three‐yr survival differed according to damage type, 78.5 percent after snapping vs. 38.4 percent after uprooting. Species differed widely in resistance to and survival after snapping and uprooting. Several species and individual traits were associated with the probability of snapping or uprooting; however, wood density was the only species trait consistently, and negatively, associated with the probability of sustaining either damage type. Survival after snapping was negatively associated with the proportion of the tree snapped off, which was determined by individual tree architecture. Species growth rate was negatively associated with survival after uprooting, indicating the importance of shade tolerance for survival after uprooting. Thus, whereas species traits seemed to exclusively underpin resistance to and survival after uprooting, they only partly accounted for snapping resistance, and did not determine the intensity of snap damage or survival after snapping. Our results highlight the importance of considering each damage type separately when considering ecological trade‐offs.     

Observational visuospatial encoding of the cache locations of others by western scrub-jays (<Emphasis Type="Italic">Aphelocoma californica</Emphasis>)

Western scrub-jays (Aphelocoma californica) hide food and rely on spatial memory to recover their caches at a later date. They also rely on observational spatial memory to steal caches made by other individuals. Successful pilfering may require an understanding of allocentric space because the observer will often be in a different position from the demonstrator when the caching event occurs. We compared cache recovery accuracy of pairs of observers that watched a demonstrator cache food. The pattern of recovery searches showed that observers were more accurate when they had observed the caching event from the same viewing direction as the demonstrator than when they had watched from the opposite direction. Search accuracy was not affected by whether or not the tray-specific local cues provided left–right landmark information (i.e. heterogeneous vs. homogeneous local cues), or whether or not the caching tray location was rotated. Taken together, these results suggest that observers have excellent spatial memory and that they have little difficulty with mental rotation.     

Establishment of native perennial shrubs in an agricultural landscape

Abstract Native vegetation has been destroyed or dramatically modified throughout agricultural regions of southern Australia. Extensive restoration of native perennial vegetation is likely to be crucial in these areas for the persistence of native plant and animal species, to ameliorate dryland salinity and soil degradation, and to maintain long‐term agricultural production. The long‐term resilience of these systems will be dependent on the ability of key functional taxa, such as perennial shrubs, to recruit and persist. In this study, we examine the factors limiting establishment of two perennial shrubs in formerly cropped land, the rare Maireana rohrlachii and the common Maireana decalvans. Field and laboratory observations suggest that establishment of both species is not limited by life‐history traits following cultivation. Both species established and persisted under varying levels of plant competition. Similarities existed between species in their initial germination rates. Weak differences were found between species in the growth and survival rates under different levels of competition. The main difference between the two species was in the decline of germinability of fruits with increasing fruit age. From the data, it is difficult to determine what factors limit the establishment of perennial shrubs in these landscapes. The main hypothesis that can be advanced is that establishment of shrub species appears to be limited by propagule availability and this is likely to be a function of past and present grazing management rather than cultivation per se. Further investigation of these land‐use practices may give greater insight into the factors affecting the establishment of this life form across these landscapes.     

城市生态韧性时空变化及情景模拟研究——以杭州市为例

从韧性的特征角度研究城市生态韧性水平的变化机制,探究城市防范化解生态风险能力的时空差异,以此明确城市分区生态治理的重要任务,是实现韧性城市生态风险防控的有利途径。从抵抗力、适应力和恢复力3个方面构建了城市生态韧性评估模型,并以杭州为例,评估了其1995—2015年城市生态韧性时空变化格局,再者利用空间自相关模型对2015年杭州生态韧性分区管理模式进行了探究。最后,基于FLUS模型模拟了2035年基准和创新创业导向的两种情景下的城市土地利用空间格局,并评估了不同城市发展情景下的生态韧性水平空间分布情况。基于以上研究得到以下结论:(1)1995—2005年,生态韧性低值区域向东北和东南方向扩张,而生态韧性高值水平区域明显减少。2005—2015年,杭州西北部和西部原本存在的中等韧性水平区域也转为低等水平。(2)2015年,城市东北区域呈现低韧性水平-高排污企业密度的集聚分布,说明该区域环境生态风险防范化解能力比较低,需要加大环境监测和生态治理的资金投入,严防重大环境污染事件的发生。(3)创新创业导向的"创新天堂"城市发展情景比基准情景下2035年杭州整体生态韧性水平更高,主要影响因素在于前...     

Functional trait responses of aquatic macroinvertebrates to simulated drought in a Neotropical bromeliad ecosystem

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Resilience indicators: prospects and limitations for early warnings of regime shifts

In the vicinity of tipping points—or more precisely bifurcation points—ecosystems recover slowly from small perturbations. Such slowness may be interpreted as a sign of low resilience in the sense that the ecosystem could easily be tipped through a critical transition into a contrasting state. Indicators of this phenomenon of ‘critical slowing down (CSD)’ include a rise in temporal correlation and variance. Such indicators of CSD can provide an early warning signal of a nearby tipping point. Or, they may offer a possibility to rank reefs, lakes or other ecosystems according to their resilience. The fact that CSD may happen across a wide range of complex ecosystems close to tipping points implies a powerful generality. However, indicators of CSD are not manifested in all cases where regime shifts occur. This is because not all regime shifts are associated with tipping points. Here, we review the exploding literature about this issue to provide guidance on what to expect and what not to expect when it comes to the CSD-based early warning signals for critical transitions.