Digital preparation of a probable neoceratopsian preserved within an egg, with comments on microstructural anatomy of ornithischian eggshells

We describe the first known embryo of a neoceratopsian dinosaur, perhaps the most ubiquitous Laurasian group of Cretaceous dinosaurs, which is preserved completely enclosed within an egg. This specimen was collected from Late Cretaceous beds of southern Mongolia, which commonly preserve fossils of the neoceratopsian, Yamaceratops dorngobiensis. The small egg was scanned using high-resolution X-ray computed tomography and digitally prepared from the matrix. The preserved and imaged elements support a diagnosis of the embryo to Neoceratopsia and allow preliminary observations of ontogenetic transformations within this group. The addition of an embryo also adds another important data point to the already impressive postnatal ontogenetic series that are available for this clade.     

联合基于野外的代谢组学和化学分析手段筛选优先关注新兴污染物：在五大湖流域的案例研究

由于毒性评估项目很难与日渐增长的需要测试的污染物保持同步,所以较难将关注点集中在影响水生生态系统的最为生物相关的污染物上。由于评估潜在毒性污染物所造成的生物影响已被证明是有效的,内生性代谢物的研究（代谢组学）对于剔除那些较低可能造成生物影响的污染物或许有一定帮助,从而找出生物重要性最高的污染物。本研究在北美五大湖流域的18个地点针对置于笼中的黑头软口鲦（Pimephales promelas）进行实验。我们测定了水体温度和水样中的污染物浓度（目标污染物132种,检出86种）,并使用1H-NMR谱测量了肝极性提取物中的内生性代谢物。利用偏最小二乘法回归来比对内生性代谢物的相对丰度与污染物浓度和环境温度。结果表明内生性极性代谢物的指标与最多49种污染物存在共同变化。因此我们认为至多52%的检出污染物与内生性代谢物变化的共同变化不显著,表明这些污染物很可能不会在这些地点造成可以检测到的影响。这是通过缩短对于实验地点有着潜在影响的污染物列表从而扫描出检出污染物生物相关性的第一步。类似的信息有助于风险评估者区分不同污染物的重要性并将重点毒性测试放在最为生物相关的污染物上。
精选自Nicol Janecko, Lucie Pokludova, Jana Blahova, Zdenka Svobodova, Ivan Literak. Linking field-based metabolomics and chemical analyses to prioritize contaminants of emerging concern in the Great Lakes basin. Environmental Toxicology and Chemistry: Volume 35, Issue 10, pages 2493–2502, October 2016. DOI: 10.1002/etc.3409
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.3409/full
     

DEVELOPMENT OF NUTRIENT SUBMODULES FOR USE IN THE GRIDDED SURFACE SUBSURFACE HYDROLOGIC ANALYSIS (GSSHA) DISTRIBUTED WATERSHED MODEL1

Abstract: A primary water quality problem caused by non-point source pollution (NPSP) is eutrophication, from excess nutrients in receiving water bodies. The control of nutrients arising from NPSP is difficult because the source areas can be hard to identify and typical treatment methods are infeasible due to the distributed nature of the pollutants. It may be possible to reduce nutrient related water quality problems through the restoration of highly disturbed watersheds with best management practices (BMPs). While restoration attempts may provide significant returns, they can be costly to implement and often are met with resistance in agricultural communities. Extending model results beyond the range of calibration to model future conditions such as for restoration scenarios requires the use of physically-based models that include the important processes that generate streamflow and material transport, uptake, loss, transformation, and recycling of nutrients and other material. The research and development objectives of the US. Army Engineer Research and Development Center (ERDC) in Vicksburg, Mississippi, are to develop a watershed assessment and management model to simulate transport, uptake, loss, transformation, and recycling of nutrients such as nitrogen and phosphorus and associated material such as sediment and organic matter. In this study we will discuss current efforts at the ERDC's Environmental Laboratory to develop a state-of-the-art watershed water quality model.     

Using ecological criteria to evaluate wilderness planning options in Idaho

Legally designated wilderness areas are acknowledged to be an important element in strategies to conserve biological diversity in United States. However, because of the restrictions on consumptive uses in wilderness, their establishment is normally contentious. Criteria for establishment have typically been associated with opportunity and aesthetic and experiential values. Biological data have not normally played a major role in guiding wilderness establishment. We present four wilderness allocation options for those public lands considered suitable for wilderness designation in Idaho. These options cover the span of choices presently available to wilderness planners in the state and range from not establishing any new wilderness areas to the inclusion of all suitable lands in wilderness. All options are evaluated using spatial biological data from the National Biological Survey's Gap Analysis Project. A conservation strategy that would protect a minimum of 10% of the area occupied by each of 113 native vegetation types and at a minimum 10% of the distribution of each of 368 vertebrate species was evaluated for each option. Only the inclusion of all suitable lands in wilderness, creating a system of 5.1 million ha came close to achieving these goals, protecting 65% of the vegetation types and 56% of the vertebrate species. We feel this approach, which allows planners to evaluate the ecological merits of proposed widerness units along with other values, can provide a means to resolve the impasse over additional wilderness designation in Idaho.     

Technique for assessing erosion risk from mountain footpaths

One of the most pressing problems facing wilderness managers in the ecologically fragile Drakensberg Mountains, South Africa, is that of path erosion, since it detracts from the wilderness experience and is very costly to remediate. As increasing demand for wilderness and outdoor recreation places greater pressure on paths and trails, it will be necessary to increase path network size and capacity, and it is important that new paths are routed such that maintenance requirements are minimal. This study describes the development of a technique based on the site and environmental variables of rainfall, topographic slope, and lithology, which enables assessment of path erosion risk before paths are planned and constructed. The technique was tested on a path at the Drakensberg resort of Loteni, and showed good correlation with actual path degradation. When used as a tool in path network planning, it can aid in the selection of low-maintenance routes and also help in planning maintenance budgets.     

Integrated Measures of Anthropogenic Stress in the U.S. Great Lakes Basin

Integrated, quantitative expressions of anthropogenic stress over large geographic regions can be valuable tools in environmental research and management. Despite the fundamental appeal of a regional approach, development of regional stress measures remains one of the most important current challenges in environmental science. Using publicly available, pre-existing spatial datasets, we developed a geographic information system database of 86 variables related to five classes of anthropogenic stress in the U.S. Great Lakes basin: agriculture, atmospheric deposition, human population, land cover, and point source pollution. The original variables were quantified by a variety of data types over a broad range of spatial and classification resolutions. We summarized the original data for 762 watershed-based units that comprise the U.S. portion of the basin and then used principal components analysis to develop overall stress measures within each stress category. We developed a cumulative stress index by combining the first principal component from each of the five stress categories. Maps of the stress measures illustrate strong spatial patterns across the basin, with the greatest amount of stress occurring on the western shore of Lake Michigan, southwest Lake Erie, and southeastern Lake Ontario. We found strong relationships between the stress measures and characteristics of bird communities, fish communities, and water chemistry measurements from the coastal region. The stress measures are taken to represent the major threats to coastal ecosystems in the U.S. Great Lakes. Such regional-scale efforts are critical for understanding relationships between human disturbance and ecosystem response, and can be used to guide environmental decision-making at both regional and local scales.     

Navigating uneven terrain: The roles of political skill and LMX differentiation in prediction of work relationship quality and work outcomes

Drawing from social/political influence, leader–member exchange (LMX), and social comparison theories, the present two‐study investigation examines three levels of LMX differentiation (i.e., individual‐level, meso‐level, and group‐level LMX differentiation) and further tests a model of the joint effects of political skill and LMX differentiation on LMX, relative LMX, and employee work outcomes. In Study 1, we used data from 231 employees and found support for the interactive effect of political skill and individual perceptions of LMX differentiation on LMX quality. We also found partial support for the moderating role of individual‐level LMX differentiation on the indirect effects of political skill on self‐rated task performance and job satisfaction via LMX. In Study 2, we used data from 185 supervisor–subordinate dyads and examined both meso‐level and group‐level LMX differentiation via a multilevel moderated mediation model. Results supported the moderating role of group‐level LMX differentiation and group mean LMX on the indirect effects of political skill on supervisor‐rated task performance and contextual performance/citizenship behavior as well as job satisfaction via relative LMX. Overall, the results suggest that politically skilled employees reap the benefits of LMX differentiation, as they enjoy higher absolute LMX and relative (i.e., to their peers) LMX quality. Copyright © 2016 John Wiley & Sons, Ltd.     

A novel concept of Fe-mineral-based magnetoreception: histological and physicochemical data from the upper beak of homing pigeons

Animals make use of the Earth’s magnetic field for navigation and regulation of vegetative functions; however, the anatomical and physiological basis for the magnetic sense has not been elucidated yet. Our recent results from histology and X-ray analyses support the hypothesis that delicate iron-containing structures in the skin of the upper beak of homing pigeons might serve as a biological magnetometer. Histology has revealed various iron sites within dendrites of the trigeminal nerve, their arrangement along strands of axons, the existence of three dendritic fields in each side of the beak with specific 3D-orientations, and the bilateral symmetry of the whole system. Element mapping by micro-synchrotron X-ray fluorescence analysis has shown the distribution of iron and its quantities. Micro-synchrotron X-ray absorption near-edge-structure spectroscopy has allowed us to unambiguously identify maghemite as the predominating iron mineral (90 vs 10% magnetite). In this paper, we show that iron-based magnetoreception needs the presence of both of these iron minerals, their specific dimensions, shapes, and arrangements in three different subcellular compartments. We suggest that an inherent magnetic enhancement process via an iron-crusted vesicle and the attached chains of iron platelets might be sufficient to account for the sensitivity and specificity required by such a magnetoreceptor. The appropriate alignment between the Earth’s magnetic field and the maghemite bands would induce a multiple attraction of the magnetite bullets perpendicular to the membrane, thus, triggering strain-sensitive membrane channels and a primary receptor potential. Due to its 3D architecture and physicochemical nature, the dendritic system should be able to separately sense the three vector components of the Earth’s local field, simultaneously—allowing birds to detect their geographic position by the magnetic vector, i.e., amplitude and direction of the local magnetic field, irrespective of the animal’s posture or movement and photoreception.