The nature and extent of interactions between the distant regions and cultures of Mesoamerica remain open to much debate. Close economic and political ties developed between Teotihuacan and the lowland Maya during the Early Classic period (AD 250–550), yet the relationship between these cultures continues to perplex scholars. This article presents an elaborately painted altar from an elite residential group at the lowland Maya centre of Tikal, Guatemala. Dating to the fifth century AD, the altar is unique in its display of Teotihuacan architectural and artistic forms, adding to evidence not only for cultural influence during this period, but also for an active Teotihuacan presence at Tikal.

Lidar reveals the presence of a precinct at the Classic Maya city of Tikal that probably reproduces the Ciudadela and Temple of the Feathered Serpent at the imperial capital of Teotihuacan.

This study supplements spatial panel econometrics techniques with qualitative GIS to analyse spatio-temporal changes in the distribution of integrated conservation–development projects relative to poaching activity and unauthorized resource use in Volcanoes National Park, Rwanda. Cluster and spatial regression analyses were performed on data from ranger monitoring containing > 35,000 combined observations of illegal activities in Volcanoes National Park, against tourism revenue sharing and conservation NGO funding data for 2006–2015. Results were enriched with qualitative GIS analysis from key informant interviews. We found a statistically significant negative linear effect of overall integrated conservation–development investments on unauthorized resource use in Volcanoes National Park. However, individually, funding from Rwanda's tourism revenue sharing policy did not have an effect in contrast to the significant negative effect of conservation NGO funding. In another contrast between NGO funding and tourism revenue sharing funding, spatial analysis revealed significant gaps in revenue sharing funding relative to the hotspots of illegal activities, but these gaps were not present for NGO funding. Insight from qualitative GIS analysis suggests that incongruity in prioritization by decision makers at least partly explains the differences between the effects of revenue sharing and conservation NGO investment. Although the overall results are encouraging for integrated conservation–development projects, we recommend increased spatial alignment of project funding with clusters of illegal activities, which can make investment decision-making more data-driven and projects more effective for conservation.

In July 2014, Indonesia implemented a safeguard tariff on galvalume, a type of galvanized flat-rolled steel. Chinese Taipei and Viet Nam challenged the measure, mainly claiming that Indonesia's administering authority failed to satisfy various substantive and procedural requirements of the GATT 1994 and the Safeguards Agreement. The Panel and AB found that the tariff was not a safeguard measure but rather was a simple increase in Indonesia's applied rate. Interestingly, Viet Nam, the largest import supplier, is a member of a free trade area with Indonesia, meaning Viet Nam is not subject to the MFN rate. Viet Nam's preferential tariff treatment likely influenced Indonesia's decision to claim the action was a safeguard. Ironically, even though the Appellate Body essentially rejected its claims, the ruling benefits Viet Nam.

The South China Sea (SCS) is a biodiversity hotspot, however, most biodiversity surveys in the region are confined to shallow water reefs. Here, we studied the benthic habitat and fish assemblages in the upper mesophotic coral ecosystems (MCEs; 30–40 m) and SWRs (8–22 m) at three geographic locations (Luzon Strait; Palawan; and the Kalayaan Group of Islands) in the eastern SCS (also called the West Philippine Sea) using diver-based survey methods. Mean coral genera and fish species richness ranged from 17–25 (per 25 m2) and 11–17 (per 250 m2) in MCEs, respectively; although none of these were novel genera/species. Coral and fish assemblages were structured more strongly by location than by depth. Location differences were associated with the variability in benthic composition, wherein locations with higher hard coral cover had higher coral genera richness and abundance. Locations with higher algae and sand cover had higher diversity and density of fish herbivores and benthic invertivores. Fishing efforts may also have contributed to among-location differences as the highly exploited location had the lowest fish biomass. The low variation between depths may be attributed to the similar benthic composition at each location, the interconnectivity between depths due to hydrological conditions, fish motility, and the common fishing gears used in the Philippines that can likely extend beyond SWRs. Results imply that local-scale factors and anthropogenic disturbances probably dampen across-depth structuring in coral genera and fish species assemblages.

The WTO Appellate Body report United States – Certain Methodologies and Their Application to Anti-Dumping Proceedings Involving China is yet another in a long line of disputes involving US Department of Commerce's dumping margin calculation methodologies. The AB ruled against the United States on three important aspects: (1) the use of the Nails test to rationalize the exceptional method in Article 2.4.2 of the Anti-Dumping Agreement so as to justify using the weighted average-to-transaction methodology in dumping margin calculations; (2) the treatment of multiple companies in a non-market economy as a single NME-wide entity; and (3) the USDOC's policy of using adverse facts available for such an entity. Yet, some aspects of the AB's decision – most notably affirming the use of average prices – significantly weaken Article 2.4.2's pattern requirement and potentially open the door to greater use of the exceptional method.

The U.S. Science Plan for Deep Ice Coring in West Antarctica calls for two ice cores to be collected. the first of these cores, from Siple Dome, was completed during the 1997/98 field season. the second core is to be collected from a site near the divide that separates ice flowing to the Ross Sea and to the Amundsen Sea.Using high-resolution, grid-based aerogeophysical surveys of the Ross/Amundsen ice-divide region, we identify seven candidate sites and assess their suitability for deep coring. We apply ice-flow and temperature calculations to predict time-scales and annual-layer resolution, and to assess the potential for basal melting for several selected sites. We conclude that basal melting is likely for sites with very thick ice, as was observed at the Byrd core site. Nevertheless, these sites are most attractive for coring since they promise recovery of a long climate record with comparatively high time resolution during the last glacial period.

Stable isotopes in ice cores are used as a proxy for the temperature at the time of snow formation. Where net accumulation rate is relatively high, snow is buried quickly and initial isotopic values are preserved. However, in low-accumulation areas, snow is exposed to lengthy vapor exchange with the atmosphere. the original isotopic signature of this snow may be modified by equilibration with atmospheric water vapor in the boundary layer over the snow surface in summer. We estimate the characteristic times for equilibration by using an electrical resistor network analogue. Warm, windy summers and low accumulation rate enhance equilibration. Although equilibration of the complete snowpack is unlikely, significant post-depositional change may occur in some Antarctic environments.

The spatial pattern of accumulation rate can be inferred from internal layers in glaciers and ice sheets. Non-dimensional analysis determines where finite strain can be neglected (‘shallow-layer approximation’) or approximated with a local one-dimensional flow model (‘local-layer approximation’), and where gradients in strain rate along particle paths must be included (‘deep layers’). We develop a general geophysical inverse procedure to infer the spatial pattern of accumulation rate along a steady-state flowband, using measured topography of the ice-sheet surface, bed and a ‘deep layer’. A variety of thermomechanical ice-flow models can be used in the forward problem to calculate surface topography and ice velocity, which are used to calculate particle paths and internal-layer shapes. An objective tolerance criterion prevents over-fitting the data. After making site-specific simplifications in the thermomechanical flow algorithm, we find the accumulation rate along a flowband through Taylor Mouth, a flank site on Taylor Dome, Antarctica, using a layer at approximately 100 m depth, or 20% of the ice thickness. Accumulation rate correlates with ice-surface curvature. At this site, gradients along flow paths critically impact inference of both the accumulation pattern, and the depth-age relation in a 100 m core.

The late-Holocene trends in δ18O differ significantly in two ice cores (30 km apart) from the area of Taylor Dome, Antarctica. It is unlikely that the trend in the core from Taylor Mouth (the flank site) is due to a standard δ18O–surface temperature relationship. Assuming that the Taylor Dome (nearsummit) core records local climate variations common to both cores, we assess two leading possible causes for the observed differences: (1) Relative to Taylor Dome, Taylor Mouth may collect snow from more sources with distinct isotopic compositions. (2) Vapor motion during prolonged near-surface exposure may cause post-depositional isotope enrichment at Taylor Mouth, where the accumulation rate is low. Our model of firn pore-space vapor and sublimating ice grains suggests that post-depositional processes can modify δ18O values by several ‰. Isotopic samples from areas with significantly different accumulation rates near Taylor Mouth could differentiate between possibilities (1) and (2).

A new model of isotopic diffusion in the upper few meters of firn tracks the isotopic composition of both the ice matrix and the pore-space vapor through time in two dimensions. Stable isotopes in the vapor phase move through the firn by diffusion along concentration gradients and by advection. Wind-driven ventilation carries atmospheric water vapor into the firn, where it mixes with existing pore-space vapor. Unlike previous models, our model allows disequilibrium between pore-space vapor and the surrounding snow grains. We also calculate the isotopic effects of ventilation-driven sublimation and condensation in the firn. Model predictions of isotopic diffusion in firn compare favorably with existing diffusion models. Model results quantify what other investigators have suggested: isotopic change in the upper few meters is more rapid than can be explained by the Whillans and Grootes (1985) model; isotopic equilibration with atmospheric vapor is an important component of post-depositional isotopic change; and ventilation enhances isotopic exchange by creating regions of relatively rapid sublimation and condensation in the firn.

To date, the spatial distribution pattern and density of Brazil nut trees in logged forest stands is unclear across the Amazon basin. We asked the following questions: (1) What are the densities and spatial distributions of Brazil nut juveniles (10 ≤ dbh < 40 cm) and adults (≥ 40 cm dbh) in three selectively logged Brazil nut concessions (1413 ha sampled) in Madre de Dios, Peru; (2) What is the spatial relationship between adults and juveniles (10 ≤ dbh < 30 cm); and (3) What is the spatial relationship between juveniles (10 ≤ dbh <30 cm) and cut stumps (≥ 10 y)? Spatial analyses were conducted using statistics derived from Ripley's K function. Juveniles were aggregated in all three concessions. Results for adult populations rejected the null hypothesis of a random distribution among trees ≥ 40 cm dbh. We did not find an attraction between juveniles and cut-stump locations, nor between adults and juveniles. The strong peaks of aggregation for juveniles and adult Brazil nuts in this study occurred at long distances (300–900 m), suggesting multiple tree canopy gaps as drivers of spatial distribution patterns, either via natural or anthropogenic sources. Our data contribute to a more thorough understanding of Brazil nut population structure in disturbed forests in south-western Amazonia.

The Indonesian archipelago is a ‘hotspot’ for invertebrate biodiversity (‘Coral Triangle’). In this area of ‘peak’ biodiversity, the origins of this high species diversity have often been debated. Xestospongia testudinaria is one of the sponge species that dominates coral reef sponge communities in this region. The role of the so-called ‘giant barrel sponge’ for the reef ecosystem has been studied repeatedly, as have its various bioactive compounds. However, the genetic variation of this iconic sponge in the region remains unknown. We investigate over 200 barrel sponge samples from Indonesia, and neighbouring as well as more distant localities (Saudi Arabia, Tanzania, Thailand, Taiwan, Java, Sulawesi and the Great Barrier Reef, Australia) using the mitochondrial cytochrome oxidase subunit 1. We compare our results with those from the studies on the congeneric barrel sponges Xestospongia muta from the Caribbean, and Xestospongia bergquistia from the Indo-Pacific, and observe a high degree of overlapping haplotypes between the three barrel sponge species, likely indicating the presence of ancestral polymorphisms. We discuss the implications of these findings to better interpret the phylogeography of barrel sponge taxa in the Indo-Pacific.

The WTO Panel report on China – Anti-dumping and Countervailing Duty Measures on Broiler Products from the United States was circulated to Members on 2 August 2013. In the report, the Panel examined a variety of issues challenged by the United States under various provisions of the General Agreement on Tariffs and Trade 1994, the Anti-dumping Agreement and the Agreement on Subsidies and Countervailing Measures. The Panel upheld the United States' claims on the majority of the issues, which covered certain procedural aspects of the anti-dumping and countervailing investigations such as the right to disclosure of ‘essential facts', as well as the substantive determinations including costing issues, the imposition of the ‘all others' rate on the basis of ‘facts available’, the price effects' analyses, the sufficiency of the public notices, and others. Notably the costing issues that came up in the case, although decided mostly on procedural grounds, provide food for thought, and are likely to feature again in future disputes.

In July 2009, Chinese steel producers of grain oriented electrical steel filed anti-dumping (AD) and countervailing duty (CVD) cases against US and Russian producers. The US challenged the duties for a variety a reasons, many of which involved deficiencies in the producers' application to China's investigating authority, the Ministry of Commerce of the People's Republic of China (MOFCOM). The US also challenged certain aspects of MOFCOM's injury analysis. The Panel and Appellate Body ruled in favor of the US on virtually every issue. Given the deficiencies in the application and China's handling of the case, the Panel and AB decisions were justified. In a larger sense, however, we believe China may well emerge as the ‘winner’ in this dispute as this case establishes important standards for allegations and evidence in applications, standards that other countries (including the US) likely have failed to meet when they have imposed AD and CVD orders on the largest target country, China.