To investigate the effect of combined end-and-shaft post-grouting on the vertical load-bearing performance of bridge-bored piles in the Dongting Lake area of Hunan, two post-grouted piles were subjected to bi-directional O-cell and top-down load tests before and after combined end-and-shaft grouting, based on the Wushi to Yiyang Expressway project. A comparative analysis was conducted on the bearing capacity, deformation characteristics, and load transfer behavior of the piles before and after grouting. This study also examined the conversion coefficient gamma values of different soil layers obtained from the bi-directional O-cell test for bearing capacity calculations. Additionally, the characteristic values of the end bearing capacity, obtained from the bi-directional O-cell and top-down load tests, were compared with the values calculated using the relevant formulas in the current standards, which validated the accuracy of existing regulations and traditional loading methods. The results indicate that the stress distribution along the pile shaft differed between the two test methods. In the bi-directional O-cell test, the side resistance developed from the end to the head, while in the top-down load test, it developed from the head to the end. After combined post-grouting, the ultimate bearing capacity of the piles significantly increased, with side resistance increasing by up to 81.03% and end resistance by up to 105.66%. The conversion coefficients for the side resistance in silty sand and gravel before and after grouting are 0.86 and 0.80 and 0.81 and 0.69, respectively. The characteristic values of the end bearing capacity, as measured by the bi-directional O-cell and top-down load tests, were substantially higher than those calculated using the current highway bridge and culvert standards, showing increases of 133.63% and 86.15%, respectively. These findings suggest that the current standard formulas are overly conservative. Additionally, the measured values from the top-down load test may underestimate the actual bearing capacity of piles in engineering projects. Therefore, it is recommended that future pile foundation designs incorporate both bi-directional O-cell testing and combined post-grouting techniques to optimize design solutions.

Ecological theory predicts that herbivory should be weaker on islands than on mainland based on the assumption that islands have lower herbivore abundance and diversity. However, empirical tests of this prediction are rare, especially for insect herbivores, and those few tests often fail to address the mechanisms behind island-mainland divergence in herbivory. In particular, past studies have not addressed the relative contribution of top-down (i.e. predator-driven) and bottom-up (i.e. plant-driven) factors to these dynamics. To address this, we experimentally excluded insectivorous vertebrate predators (e.g. birds, bats) and measured leaf traits associated with herbivory in 52 populations of 12 oak (Quercus) species in three island-mainland sites: The Channel Islands of California vs. mainland California, Balearic Islands vs. mainland Spain, and the island Bornholm vs. mainland Sweden (N = 204 trees). In each site, at the end of the growing season, we measured leaf damage by insect herbivores on control vs. predator-excluded branches and measured leaf traits, namely: phenolic compounds, specific leaf area, and nitrogen and phosphorous content. In addition, we obtained climatic and soil data for island and mainland populations using global databases. Specifically, we tested for island-mainland differences in herbivory, and whether differences in vertebrate predator effects or leaf traits between islands and mainland contributed to explaining the observed herbivory patterns. Supporting predictions, herbivory was lower on islands than on mainland, but only in the case of Mediterranean sites (California and Spain). We found no evidence for vertebrate predator effects on herbivory on either islands or mainland in any study site. In addition, while insularity affected leaf traits in some of the study sites (Sweden-Bornholm and California), these effects were seemingly unrelated to differences in herbivory. Synthesis. Our results suggest that vertebrate predation and the studied leaf traits did not contribute to island-mainland variation patterns in herbivory, calling for more nuanced and comprehensive investigations of predator and plant trait effects, including measurements of other plant traits and assessments of predation by different groups of natural enemies. La teor & iacute;a ecol & oacute;gica predice que la herbivor & iacute;a ha de ser m & aacute;s d & eacute;bil en las islas que en el continente, ya que las islas tienen una menor abundancia y diversidad de herb & iacute;voros. Sin embargo, todav & iacute;a no contamos con suficiente evidencia emp & iacute;rica que apoye estas predicciones, especialmente en lo que se refiere a la herbivor & iacute;a por insectos, y los pocos estudios que existen a menudo no abordan los mecanismos que generan estos patrones de divergencia entre islas y continente en los niveles de herbivor & iacute;a. En particular, las investigaciones previas no han examinado la contribuci & oacute;n relativa de las fuerzas top-down (es decir, efectos mediados por los depredadores) y bottom-up (es decir, efectos mediados por los rasgos funcionales de las plantas) en estas din & aacute;micas. En este trabajo, excluimos experimentalmente a depredadores insect & iacute;voros vertebrados (p. ej., aves, murci & eacute;lagos) y medimos rasgos foliares asociados con la herbivor & iacute;a en 52 poblaciones de 12 especies de robles (Quercus) en tres sitios insulares y continentales: las Islas del Canal de California vs. California continental, las Islas Baleares vs. Espa & ntilde;a continental, y la isla de Bornholm vs. Suecia continental (N = 204 & aacute;rboles). En cada sitio, al final de la & eacute;poca de crecimiento, medimos el da & ntilde;o foliar causado por insectos herb & iacute;voros en ramas control vs. ramas con exclusi & oacute;n de depredadores, y medimos diferentes rasgos foliares, en particular, la concentraci & oacute;n de compuestos fen & oacute;licos, el & aacute;rea foliar espec & iacute;fica y el contenido de nitr & oacute;geno y f & oacute;sforo. Adem & aacute;s, obtuvimos datos clim & aacute;ticos y de suelo de las poblaciones insulares y continentales utilizando bases de datos globales. Espec & iacute;ficamente, evaluamos los efectos de la insularidad sobre la herbivor & iacute;a y si exist & iacute;an patrones contrastados de los efectos de depredaci & oacute;n y expresi & oacute;n de rasgos foliares entre islas y continentes que contribuyesen a explicar los patrones observados en la herbivor & iacute;a. De acuerdo con la teor & iacute;a ecol & oacute;gica, la herbivor & iacute;a fue menor en las islas en comparaci & oacute;n con el continente, pero solo en el caso de los sitios mediterr & aacute;neos (California y Espa & ntilde;a). No encontramos evidencia de efectos de los depredadores sobre la herbivor & iacute;a en ninguno de los sitios de estudio, ya sea en las islas o en el continente. Adem & aacute;s, aunque la insularidad afect & oacute; a la expresi & oacute;n de rasgos foliares en algunos de los sitios de estudio (Suecia-Bornholm y California), estos efectos no estuvieron aparentemente relacionados con las diferencias observadas en la herbivor & iacute;a. S & iacute;ntesis. Nuestros resultados sugieren que la depredaci & oacute;n por vertebrados y los rasgos foliares estudiados no contribuyeron a los patrones de variaci & oacute;n entre islas y continente observados en los niveles de herbivor & iacute;a, lo que plantea la necesidad de investigaciones m & aacute;s exhaustivas que incluyan la evaluaci & oacute;n de otros rasgos funcionales y evaluaciones de la depredaci & oacute;n por otros grupos de enemigos naturales de los herb & iacute;voros.

This work uses a mixture of observations from surface remote sensing (AERONET) and satellite remote sensing (OMI) to uniquely compute the atmospheric column loading of black carbon (BC) mass concentration density (MCD) and number concentration density (NCD) on a grid-by-grid, day-by-day basis at 0.25 degrees x0.25 degrees over rapidly developing and biomass burning (BB) impacted regions in South, Southeast, and East Asia. This mixture of observations is uniformly analyzed based on OMI NO2 retrievals, OMI Near ultraviolet band absorption aerosol optical depth and single scattering albedo (SSA), and AERONET visible and near-infrared band SSA observations, in connection with an inversely applied MIE mixing model approach. This method uniquely solves for the unbiased spatial and temporal domains based on variance maximization of daily NO2. These locations in space and time are then used to quantify the distribution of all possible individual particle core and refractory shell sizes as constrained by all band-by-band observations of SSA from AERONET. Finally, the range of NCD and MCD are computed from the constrained range of per-particle core and refractory shell size on a grid-by-grid and day-byday basis. The maps of MCD and NCD are consistent in space and time with known urban, industrial, and BB sources. The statistical distributions are found to be non-normal, with the region-wide mean, 25th, 50th, and 75th percentile MCD [mg/m2] of 90.3, 56.1, 81.1, and 111 respectively, and NCD [x1012 particles/m2] of 8.76, 4.63, 7.39, and 11.3 respectively. On a grid-by-grid basis, a significant amount of variation is found, particularly over Myanmar, Laos, northern Thailand, and Vietnam, with this subregional mean, 25th, 50th, and 75th MCD [mg/m2] of 90.7, 56.1, 81.3, and 112 respectively and NCD [x1012 particles/m2] of 9.66, 5.49, 8.33, and 12.3 respectively. On a day-to-day basis, events are determined 121 days in 2016, during which the computed statistics of MCD and NCD have mean and uncertainty ranges which scale with each other. However, there are 11 days where the uncertainty ratio of NCD values is larger than 1 while the uncertainty ratio of MCD is small, and 5 days where the reverse is observed, indicating that the particle size is strongly atypical on these days, consistent with mixed aerosol sources, a substantial change in the aerosol aging, or other such factors including a substantial region of overlap between BB and urban sources. The high values observed from March to May lead to an extended BB season as compared to previous work focusing on fire radiative power, NO2, and models, which show a shorter season (usually ending in early April). The results are consistent with BC being able to transport significant distances. The new approach is anticipated to provide support for improving radiative forcing calculations, estimating emissions inventories, and providing a basis by which models can compare against observations.

Plant-soil interactions have bottom-up and top-down effects within a plant community. Heavy metal pollution can change plant-soil interactions, directly influence bottom-up effects and indirectly affect herbivores within the community. In turn, herbivores can affect plant-soil interactions through top-down effects. However, the combined effects of heavy metals and herbivores on soil enzymes, plants and herbivores have rarely been reported. Therefore, the effects of lead (Pb), Spodoptera litura and their combined effects on soil enzyme activities, pakchoi nutrition, defence compounds and S. litura fitness were examined here. Results showed that Pb, S. litura and their combined effects significantly affected soil enzymes, pakchoi and S. litura. Specifically, exposure to double stress (Pb and S. litura) decreased soil urease, phosphatase and sucrase activities compared with controls. Furthermore, the soluble protein and sugar contents of pakchoi decreased, and the trypsin inhibitor content and antioxidant enzyme activity increased. Finally, the S. litura development period was extended, and survival, emergence rates and body weight decreased after exposure to double stress. The combined stress of Pb and S. litura significantly decreased soil enzyme activities. Heavy metal accumulation in plants may create a superposition or synergistic effect with heavy metal-mediated plant chemical defence, further suppressing herbivore development. Pb, S. litura and their combined effects inhibited soil enzyme activities, improved pakchoi resistance and reduced S. litura development. The results reveal details of soil-plant-herbivore interactions and provide a reference for crop pest control management in the presence of heavy metal pollution.

高原积雪对太阳活动的响应研究是一个较新的领域,在对前期研究成果进行回顾和梳理的基础上,展示了最新的研究成果。研究结果表明,高原积雪时空分布对太阳活动有较为显著的响应,其机理是太阳活动通过bottom-up机制和top-down机制共同作用影响高原积雪。太阳活动可以引起全球0～200 m海温异常和潜热通量异常,通过改变海气相互作用进一步影响高原降水(积雪)异常,放大太阳活动的作用;另一方面,太阳活动通过影响平流层大气温度和环流,影响平流层和对流层大气之间的相互作用,进而改变对流层大气环流和风场,导致高原积雪异常。对未来的研究工作进行了展望,研究结果表明:数值试验模拟太阳活动影响高原积雪的关键在于气候系统模式需要包含细致的高层大气化学过程和海气耦合过程。

高原积雪对太阳活动的响应研究是一个较新的领域,在对前期研究成果进行回顾和梳理的基础上,展示了最新的研究成果。研究结果表明,高原积雪时空分布对太阳活动有较为显著的响应,其机理是太阳活动通过bottom-up机制和top-down机制共同作用影响高原积雪。太阳活动可以引起全球0～200 m海温异常和潜热通量异常,通过改变海气相互作用进一步影响高原降水(积雪)异常,放大太阳活动的作用;另一方面,太阳活动通过影响平流层大气温度和环流,影响平流层和对流层大气之间的相互作用,进而改变对流层大气环流和风场,导致高原积雪异常。对未来的研究工作进行了展望,研究结果表明:数值试验模拟太阳活动影响高原积雪的关键在于气候系统模式需要包含细致的高层大气化学过程和海气耦合过程。

高原积雪对太阳活动的响应研究是一个较新的领域,在对前期研究成果进行回顾和梳理的基础上,展示了最新的研究成果。研究结果表明,高原积雪时空分布对太阳活动有较为显著的响应,其机理是太阳活动通过bottom-up机制和top-down机制共同作用影响高原积雪。太阳活动可以引起全球0～200 m海温异常和潜热通量异常,通过改变海气相互作用进一步影响高原降水(积雪)异常,放大太阳活动的作用;另一方面,太阳活动通过影响平流层大气温度和环流,影响平流层和对流层大气之间的相互作用,进而改变对流层大气环流和风场,导致高原积雪异常。对未来的研究工作进行了展望,研究结果表明:数值试验模拟太阳活动影响高原积雪的关键在于气候系统模式需要包含细致的高层大气化学过程和海气耦合过程。

Black carbon (BC) is an important aerosol constituent in the atmosphere and climate forcer. A good understanding of the radiative forcing of BC and associated climate feedback and response is critical to minimize the uncertainty in predicting current and future climate influenced by anthropogenic aerosols. One reason for this uncertainty is that current emission inventories of BC are mostly obtained from the so-called bottom-up approach, an approach that derives emissions based on categorized emitting sources and emission factors used to convert burning mass to emissions. In this work, we provide a first global-scale top-down estimation of global BC emissions, as well as an estimated error range, by using a Kalman Filter. This method uses data of both column aerosol absorption optical depth and surface concentrations from global and regional networks to constrain our fully coupled climate-aerosol-urban model and thus to derive an optimized estimate of BC emissions as 17.85.6 Tg/yr, a factor of more than 2 higher than commonly used global BC emissions data sets. We further perform 22 additional optimization simulations that incorporate the known uncertain ranges of various important physical, model, and measurement parameters and still yield an optimized value within the above given range, from a low of 14.6 Tg/yr to a high of 22.2 Tg/yr. Furthermore, we show that the emissions difference between our optimized and a priori estimation is not uniform, with East Asia, Southeast Asia, and Eastern Europe underestimated, while North America is overestimated in the a priori inventory.