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.

Some economists argue that consumption of publicly visible goods is driven by social status. Making a causal inference about this claim is difficult with observational data. We conduct an experiment in which we vary both whether a purchase of a physical product is publicly visible or kept private and whether the income used for purchase is linked to social status or randomly assigned. Making consumption choices visible leads to a large increase in demand when income is linked to status, but not otherwise. We investigate the characteristics that mediate this effect and estimate its impact on welfare.

Debate surrounds the early peopling of the Arabian Peninsula. The first evidence of the Levallois lithic technology in the Huqf area of south-eastern Arabia now extends the Middle Palaeolithic record of hominin activity into central Oman and helps to diversify the picture of Arabian prehistory.

Frontal ablation, the combination of submarine melting and iceberg calving, changes the geometry of a glacier's terminus, influencing glacier dynamics, the fate of upwelling plumes and the distribution of submarine meltwater input into the ocean. Directly observing frontal ablation and terminus morphology below the waterline is difficult, however, limiting our understanding of these coupled ice–ocean processes. To investigate the evolution of a tidewater glacier's submarine terminus, we combine 3-D multibeam point clouds of the subsurface ice face at LeConte Glacier, Alaska, with concurrent observations of environmental conditions during three field campaigns between 2016 and 2018. We observe terminus morphology that was predominately overcut (52% in August 2016, 63% in May 2017 and 74% in September 2018), accompanied by high multibeam sonar-derived melt rates (4.84 m d−1 in 2016, 1.13 m d−1 in 2017 and 1.85 m d−1 in 2018). We find that periods of high subglacial discharge lead to localized undercut discharge outlets, but adjacent to these outlets the terminus maintains significantly overcut geometry, with an ice ramp that protrudes 75 m into the fjord in 2017 and 125 m in 2018. Our data challenge the assumption that tidewater glacier termini are largely undercut during periods of high submarine melting.

The Hierarchical Taxonomy of Psychopathology (HiTOP) has emerged out of the quantitative approach to psychiatric nosology. This approach identifies psychopathology constructs based on patterns of co-variation among signs and symptoms. The initial HiTOP model, which was published in 2017, is based on a large literature that spans decades of research. HiTOP is a living model that undergoes revision as new data become available. Here we discuss advantages and practical considerations of using this system in psychiatric practice and research. We especially highlight limitations of HiTOP and ongoing efforts to address them. We describe differences and similarities between HiTOP and existing diagnostic systems. Next, we review the types of evidence that informed development of HiTOP, including populations in which it has been studied and data on its validity. The paper also describes how HiTOP can facilitate research on genetic and environmental causes of psychopathology as well as the search for neurobiologic mechanisms and novel treatments. Furthermore, we consider implications for public health programs and prevention of mental disorders. We also review data on clinical utility and illustrate clinical application of HiTOP. Importantly, the model is based on measures and practices that are already used widely in clinical settings. HiTOP offers a way to organize and formalize these techniques. This model already can contribute to progress in psychiatry and complement traditional nosologies. Moreover, HiTOP seeks to facilitate research on linkages between phenotypes and biological processes, which may enable construction of a system that encompasses both biomarkers and precise clinical description.

Regime change often exacerbates ethnic conflict. This article examines the curious case of Myanmar, where a 2021 military coup was met, on the surface, with broad-based resistance across a divided society. An important question that therefore arises is whether, below the surface, this unity also took a more positive form of national solidarity. Were deep ethnic cleavages intensified or alleviated by the 2021 coup? This question bears theoretical relevance for the study of ethnic conflict and has social relevance for a nation marked by a long history of civil war and a recent experience of genocide against Rohingya Muslims. The article engages in a systematic examination of 180 social media posts uploaded in Burmese by key opinion leaders both before and after the coup. A qualitative analysis of major positive and negative themes indicates a shift in attitudes. The quantitative analysis shows that ethnic relations, measured by a change in themes, ratings and virality, improved significantly in the immediate aftermath of Myanmar's 2021 coup.

The Centers for Disease Control and Prevention define 6 intervals of a pandemic: (1) investigation of cases, (2) recognition of the increased potential for ongoing transmission, (3) initiation of a pandemic wave, (4) acceleration of a pandemic wave, (5) deceleration of a pandemic wave, and (6) preparation for future pandemic waves. Each of these stages has 8 domains. Following China’s coronavirus disease 2019 (COVID-19) outbreak announcement, Israel’s National Emergency Medical Services (EMS) Organization immediately began working in conjunction with the Ministry of Health (MOH) to address the threat of the COVID-19 outbreak. This article will describe how a national EMS organization acted according to these pandemic intervals and domains. In the initial stages, EMS managed a checkpoint in the international airport voluntarily testing people for febrile symptoms. Calls to the dispatch centers that aroused the suspicion of COVID-19 resulted in EMS transport to the hospital with protective gear. During the period of first exposure, the scope of the medical emergency number was increased to include questions concerning coronavirus, telemedicine, and home sampling by protected EMS workers. In the contagion stages, epidemiological tests were conducted by the MOH, and EMS began operating dedicated telephone triage, mass drive-through sampling, and finally, administration of vaccinations.

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.

Healthcare workers (HCWs) not fulfilling the coronavirus disease 2019 (COVID-19) case definition underwent severe acute respiratory coronavirus virus 2 (SARS-CoV-2) screening. Risk of exposure, adherence to personal protective equipment (PPE), and symptoms were assessed. In total, 2,000 HCWs were screened: 5.5% were positive for SARS-CoV-2 by polymerase chain reaction (PCR). There were no differences in PPE use between SARS-CoV-2–positive and –negative HCWs (adherence, >90%). Nursing and kitchen staff were independently associated with positive SARS-CoV-2 results.

This paper provides an up-to-date review of the problems related to the generation, detection and mitigation of strong electromagnetic pulses created in the interaction of high-power, high-energy laser pulses with different types of solid targets. It includes new experimental data obtained independently at several international laboratories. The mechanisms of electromagnetic field generation are analyzed and considered as a function of the intensity and the spectral range of emissions they produce. The major emphasis is put on the GHz frequency domain, which is the most damaging for electronics and may have important applications. The physics of electromagnetic emissions in other spectral domains, in particular THz and MHz, is also discussed. The theoretical models and numerical simulations are compared with the results of experimental measurements, with special attention to the methodology of measurements and complementary diagnostics. Understanding the underlying physical processes is the basis for developing techniques to mitigate the electromagnetic threat and to harness electromagnetic emissions, which may have promising applications.

Ice mélange has been postulated to impact glacier and fjord dynamics through a variety of mechanical and thermodynamic couplings. However, observations of these interactions are very limited. Here, we report on glaciological and oceanographic data that were collected from 2016 to 2017 at LeConte Glacier and Bay, Alaska, and serendipitously captured the formation, flow and break-up of ephemeral ice mélange. Sea ice formed overnight in mid-February. Over the subsequent week, the sea ice and icebergs were compacted by the advancing glacier terminus, after which the ice mélange flowed quasi-statically. The presence of ice mélange coincided with the lowest glacier velocities and frontal ablation rates in our record. In early April, increasing glacier runoff and the formation of a sub-ice-mélange plume began to melt and pull apart the ice mélange. The plume, outgoing tides and large calving events contributed to its break-up, which took place over a week and occurred in pulses. Unlike observations from elsewhere, the loss of ice mélange integrity did not coincide with the onset of seasonal glacier retreat. Our observations provide a challenge to ice mélange models aimed at quantifying the mechanical and thermodynamic couplings between ice mélange, glaciers and fjords.

We present a workflow to track icebergs in proglacial fjords using oblique time-lapse photos and the Lucas-Kanade optical flow algorithm. We employ the workflow at LeConte Bay, Alaska, where we ran five time-lapse cameras between April 2016 and September 2017, capturing more than 400 000 photos at frame rates of 0.5–4.0 min−1. Hourly to daily average velocity fields in map coordinates illustrate dynamic currents in the bay, with dominant downfjord velocities (exceeding 0.5 m s−1 intermittently) and several eddies. Comparisons with simultaneous Acoustic Doppler Current Profiler (ADCP) measurements yield best agreement for the uppermost ADCP levels (~ 12 m and above), in line with prevalent small icebergs that trace near-surface currents. Tracking results from multiple cameras compare favorably, although cameras with lower frame rates (0.5 min−1) tend to underestimate high flow speeds. Tests to determine requisite temporal and spatial image resolution confirm the importance of high image frame rates, while spatial resolution is of secondary importance. Application of our procedure to other fjords will be successful if iceberg concentrations are high enough and if the camera frame rates are sufficiently rapid (at least 1 min−1 for conditions similar to LeConte Bay).