Method for culturing Candidatus Ornithobacterium hominis.

Candidatus Ornithobacterium hominis has been detected in nasopharyngeal microbiota sequence data from around the world. This report provides the first description of culture conditions for isolating this bacterium. The availability of an easily reproducible culture method is expected to facilitate deeper understanding of the clinical significance of this species

The role of species composition in the emergence of alternate vegetation states in a temperate rainforest system

Context: Forest systems are dynamic and can alternate between alternative stable states in response to climate, disturbance and internal abiotic and biotic conditions. Switching between states depends on the crossing of critical thresholds and the establishment of feedbacks that drive (and maintain) changes in ecosystem functioning. The nature of these thresholds and the workings of these feedbacks have been well-researched, however, the factors that instigate movement toward and across a threshold remain poorly understood. Objectives: In this paper, we explore the role of species composition in initiating ecosystem state change in a temperate landscape mosaic of fire-prone and fire-sensitive vegetation systems.Methods: We construct two 12-kyr palaeocecological records from two proximal (230 m apart) sites in Tasmania, Australia, and apply the Alternative Stable States model as a framework to investigate ecosystem feedbacks and resilience threshold dynamics. Results: Our results indicate that, in this system, invasion by pyrogenic Eucalyptus species is a key factor in breaking down negative (stabilising) feedbacks that maintain pyrophobic sub-alpine rainforest.Conclusions: We conclude that the emergence of an alternative stable pyrogenic state in these relic rainforest systems depends on the extent of pyrophytic species within the system. These findings are critical for understanding resilience in forest ecosystems under future climate and land management changes and are relevant to fire-adapted cool-temperate ecosystems globally

The influence of climatic change, fire and species invasion on a Tasmanian temperate rainforest system over the past 18,000 years

We aim to understand how did cool temperate rainforest respond to changes in climate and fire activity over the past 18 kcal yrs, interrogating the role that flammable plant species (such as Eucalyptus) have in the long-term dynamics of rainforest vegetation. We used high-resolution pollen and charcoal analysis, radiometric dating (lead and carbon), modern pollen-vegetation relationships, detrended correspondence analysis, rarefaction (palynological richness), rate of change and granger causality to understand the patterns and drivers of change in cool temperate rainforest from the sediments of Lake Vera, southwest Tasmania through time. We record clear changes in key rainforest taxa in response to climatic change throughout the record. The spread of rainforest through the lake catchment in the early and mid- Holocene effectively negated disturbance from fire despite a region-wide peak in fire activity. An anomalously dry period in the late-Holocene resulted in a local fire that facilitated the establishment of Eucalyptus within the local catchment. Granger causality tests reveal a significant lead of Eucalyptus over fire activity in the Holocene, indicating that fires were enhanced by this pyrogenic taxon following establishment

Non-invasive stimulation of the social brain: the methodological challenges

Use of non-invasive brain stimulation methods (NIBS) has become a common approach to study social processing in addition to behavioural, imaging and lesion studies. However, research using NIBS to investigate social processing faces challenges. Overcoming these is important to allow valid and reliable interpretation of findings in neurotypical cohorts, but also to allow us to tailor NIBS protocols to atypical groups with social difficulties. In this review, we consider the utility of brain stimulation as a technique to study and modulate social processing. We also discuss challenges that face researchers using NIBS to study social processing in neurotypical adults with a view to highlighting potential solutions. Finally, we discuss additional challenges that face researchers using NIBS to study and modulate social processing in atypical groups. These are important to consider given that NIBS protocols are rarely tailored to atypical groups before use. Instead, many rely on protocols designed for neurotypical adults despite differences in brain function that are likely to impact response to NIBS

A broader view of collapse: Using palaeoecological techniques to reconstruct occupation dynamics across a networked society undergoing transformation

Societies increase in complexity via the growth and fragmentation of networks. City networks, for example, increasingly comprise our globalised landscape, and most social, political and economic systems operate across these spatial frameworks. The organisational structure that these city networks develop reveals much about the way these networks function and their susceptibility to undergo change in the face of significant environmental or political stress. When disruption in these networks occurs, the way these networks transform in time and space can also expose the nature of the relationships that operate between primary and secondary cities. During the Angkor period (9th-15th centuries CE), the Khmer kingdom extended across the majority of Southeast Asia, and comprised a capital (Angkor) connected to a network of secondary cities. By the mid-15th century however, severe climate stress befell the region, and Angkor was abandoned by the political and elite in favour of smaller centres on the kingdom’s southern periphery. Supposedly, this event coincided with the abandonment of several other key secondary cities, and the unravelling of the Angkor-period city network. Palaeoecological analysis (sedimentary, pollen and charcoal) provides an innovative approach to reconstructing the occupation dynamics, and thus the timing of abandonment, of two key secondary cities during this transformation period. Results suggest that both cities maintained intensive land uses through much of the Angkor period, before land use attenuated and Angkor-period water management techniques ceased prior to the presumed abandonment of Angkor, as power in the capital waned. These results suggest a high degree of integration and interdependence between Angkor and its network of secondary cities had been reached by the end of the Angkor period

Re-evaluating the occupation history of Koh Ker, Cambodia, during the Angkor period: A palaeo-ecological approach.

Throughout the Angkor period (9th to 15th centuries CE), the Khmer kingdom maintained a series of interconnected cities and smaller settlements across its territory on mainland Southeast Asia. One such city was Koh Ker, which for a brief period in the 10th century CE even served as a royal capital. The complexity of the political landscape meant the Khmer kings and the elite were particularly mobile through the Angkor period, and rupture in royal houses was common. However, while the historical record chronicles the 10th century migration of the royal seat from Koh Ker back to Angkor, the fate of Koh Ker's domestic population has remained unknown. In this article, we reconstruct the settlement history of Koh Ker, using palaeoecological and geoarchaeological techniques, and show that human activity and land use persisted in the city for several centuries beyond the city's abandonment by the royal court. These results highlight the utility of multi-proxy environmental reconstructions of Khmer urban settlements for re-evaluating prevailing assumptions regarding the use and occupation of Angkor-period cities

The environmental context of a city in decline: The vegetation history of a Khmer peripheral settlement during the Angkor period

During the Angkor period (9th to 15th centuries C.E.) the Khmer kingdom extended across much of mainland Southeast Asia. The primate city of Angkor was located on the floodplains to the north of the Tonle Sap and connected to a network of secondary cities across the kingdom via formal road or navigable river systems. Preah Khan of Kompong Svay was one such secondary city, and was positioned on the eastern margins of Khmer territory approximately 100 km from Angkor. Stylistic dating of Preah Khan's temple architecture revealed that the majority of building works was conducted between the 11th and 13th centuries C.E., however only minimal archaeological evidence for occupation during this period has been found. This paper presents a record of environmental change that re-evaluates the settlement history of Preah Khan, and suggests that occupation and land use change was occurring at least between the early 12th and late 14th centuries C.E. Signs of gradual land use attenuation and a reduction in water infrastructure management are evident from the late 13th century through to the late 14th century C.E., and during the mid-14th century an apparent shift in the utilisation of the city occurs. This study helps to address the relative lack of research into cities outside the Angkor region, and demonstrates the value of using palaeoecological evidence for unravelling the complexity of settlement history in Angkor-period cities, particularly through the waning phases of occupation.This work was supported by the Australian Research Council Discovery Project (grants DP170102574 and DP0987878), the Australian Institute of Nuclear Science and Engineering grant 11/003 and the National Geographic Society CRE grant 8599-09

A new ecohydraulic management paradigm for salt affected ecosystems and wetlands in low-gradient semi-arid environments

Land clearing for dryland agriculture has altered landscape water balance and is associated with severe valley-floor secondary dryland salinity within parts of Australia, South-East Asia, Africa, North and South America. The pervasive hydrologic process-response model is termed the “hillslope recharge-discharge model” (HRD Model), and attributes salinisation to increased hillslope recharge and rising groundwater tables resulting from reduced evapotranspiration potential following land clearing. New research suggests that internal redistribution of surface water from moderately-sloped hillslopes onto low-gradient broad valley floors, termed the “shedding-receiving model”, may be a significant additional salinisation mechanism and alternative management strategies may be required. A meso-scale surface water gauging network and four valley floor surface water-groundwater interaction sites were established in the Toolibin Lake catchment in southwestern Australia. Based on two years of data, we confirm that the shedding-receiving model holds in this landscape, operating in combination with the pervasive HRD model. There is significant rainfall runoff from moderately sloped uplands, onto low gradient valley floors and high transmission losses result from top-down preferential pathway recharge after the break of season. A new management paradigm was proposed to address the internal runoff redistribution and salt exfiltration mechanisms caused by the shedding receiving behaviour. A lowgradient, broad-based channel, approximately 25m wide, 0.4m deep and running at the valley floor gradient (~0.0003 – 0.0015) was designed to carry a 1:3yr flow. Insights gained from this study of the hydrodynamics suggests that this new approach offers significant opportunity to improve local and downstream resource condition

Distinguishing the pollen of Dipterocarpaceae from the seasonally dry, and moist tropics of south-east Asia using light microscopy

The Dipterocarpaceae family is ubiquitous across mainland and maritime south-east Asia. Species within the family are often so well-adapted to – and prolific within – ecologically distinct forest types, that they are used as habitat indicators within forestry and ecological research. The limited work on the classification of Dipterocarpaceae pollen under light microscopy, however, means that paleoecologists working in the region are currently unable to link fossil pollen to indicator species/assemblages with any confidence. As a consequence, ecologically meaningful and habitat-specific data are homogenized in the paleorecord.This work was funded by the Australian Research Council (grant # DP160102587)

Geoarchaeological evidence from Angkor, Cambodia, reveals a gradual decline rather than a catastrophic 15th-century collapse

International audienceAlternative models exist for the movement of large urban populations following the 15th-century CE abandonment of Angkor, Cambodia. One model emphasizes an urban diaspora following the implosion of state control in the capital related, in part, to hydroclimatic variability. An alternative model suggests a more complex picture and a gradual rather than catastrophic demographic movement. No decisive empirical data exist to distinguish between these two competing models. Here we show that the intensity of land use within the economic and administrative core of the city began to decline more than one century before the Ayutthayan invasion that conventionally marks the end of the Angkor Period. Using paleobotanical and stratigraphic data derived from radiometrically dated sediment cores extracted from the 12th-century walled city of Angkor Thom, we show that indicia for burning, forest disturbance, and soil erosion all decline as early as the first decades of the 14th century CE, and that the moat of Angkor Thom was no longer being maintained by the end of the 14th century. These data indicate a protracted decline in occupation within the economic and administrative core of the city, rather than an abrupt demographic collapse, suggesting the focus of power began to shift to urban centers outside of the capital during the 14th century. Angkor | collapse | Cambodia | archaeolog