431 research outputs found
Basal Primatomorpha colonized Ellesmere Island (Arctic Canada) during the hyperthermal conditions of the early Eocene climatic optimum
Anthropogenically induced warming is transforming Arctic ecosystems across a geologically short timescale, but earlier episodes of Earth history provide insights on the nature and limitations of biotic change in a rapidly warming Arctic. Late early Eocene strata (~52 Ma) of the Margaret Formation on Ellesmere Island, Nunavut, Canada sample a warm temperate ecosystem with a polar light regime situated at ~77°N paleolatitude. This extinct boreal ecosystem hosted a diversity of early Cenozoic vertebrates, including thermophilic taxa such as crocodilians and tapiroid perissodactyls. Here we describe two new species of the early primatomorphan Ignacius from Ellesmere, which are by far the northernmost known records for Paleogene Primatomorpha. Ellesmere species of Ignacius are sister taxa, indicating a single colonization of Ellesmere from farther south in North America coincident with the onset of the hyperthermal Early Eocene Climatic Optimum (EECO). The Ellesmere Ignacius clade differs from closely related taxa inhabiting mid-latitudes in being larger (thereby conforming to Bergmann’s rule) and having modified dentition and muscles of mastication for a dietary regime emphasizing hard objects, possibly reflecting an increased reliance on fallback foods during long polar winters. The late early Eocene mammalian fauna of Ellesmere indicates that its unique paleoenvironment rendered it uninhabitable to some clades, including euprimates, while selected taxa were able to adapt to its challenging conditions and diversify
Recommended from our members
Climate change increases riverine carbon outgassing, while export to the ocean remains uncertain
Any regular interaction of land and river during flooding affects carbon pools within the terrestrial system, riverine carbon and carbon exported from the system. In the Amazon basin carbon fluxes are considerably influenced by annual flooding, during which terrigenous organic material is imported to the river. The Amazon basin therefore represents an excellent example of a tightly coupled terrestrial–riverine system. The processes of generation, conversion and transport of organic carbon in such a coupled terrigenous–riverine system strongly interact and are climate-sensitive, yet their functioning is rarely considered in Earth system models and their response to climate change is still largely unknown. To quantify regional and global carbon budgets and climate change effects on carbon pools and carbon fluxes, it is important to account for the coupling between the land, the river, the ocean and the atmosphere. We developed the RIVerine Carbon Model (RivCM), which is directly coupled to the well-established dynamic vegetation and hydrology model LPJmL, in order to account for this large-scale coupling. We evaluate RivCM with observational data and show that some of the values are reproduced quite well by the model, while we see large deviations for other variables. This is mainly caused by some simplifications we assumed. Our evaluation shows that it is possible to reproduce large-scale carbon transport across a river system but that this involves large uncertainties. Acknowledging these uncertainties, we estimate the potential changes in riverine carbon by applying RivCM for climate forcing from five climate models and three CO2 emission scenarios (Special Report on Emissions Scenarios, SRES). We find that climate change causes a doubling of riverine organic carbon in the southern and western basin while reducing it by 20% in the eastern and northern parts. In contrast, the amount of riverine inorganic carbon shows a 2- to 3-fold increase in the entire basin, independent of the SRES scenario. The export of carbon to the atmosphere increases as well, with an average of about 30%. In contrast, changes in future export of organic carbon to the Atlantic Ocean depend on the SRES scenario and are projected to either decrease by about 8.9% (SRES A1B) or increase by about 9.1% (SRES A2). Such changes in the terrigenous–riverine system could have local and regional impacts on the carbon budget of the whole Amazon basin and parts of the Atlantic Ocean. Changes in riverine carbon could lead to a shift in the riverine nutrient supply and pH, while changes in the exported carbon to the ocean lead to changes in the supply of organic material that acts as a food source in the Atlantic. On larger scales the increased outgassing of CO2 could turn the Amazon basin from a sink of carbon to a considerable source. Therefore, we propose that the coupling of terrestrial and riverine carbon budgets should be included in subsequent analysis of the future regional carbon budget
Benthic enrichment in the Georgia Bight related to Gulf Stream intrusions and estuarine outwelling
The distribution patterns of benthic biomass (microbiota, meiofauna, and macrofauna) over the expansive continental shelf of the Georgia Bight suggest nutrient inputs from intrusions of deep Gulf Stream waters at the shelf break…
In-Network Outlier Detection in Wireless Sensor Networks
To address the problem of unsupervised outlier detection in wireless sensor
networks, we develop an approach that (1) is flexible with respect to the
outlier definition, (2) computes the result in-network to reduce both bandwidth
and energy usage,(3) only uses single hop communication thus permitting very
simple node failure detection and message reliability assurance mechanisms
(e.g., carrier-sense), and (4) seamlessly accommodates dynamic updates to data.
We examine performance using simulation with real sensor data streams. Our
results demonstrate that our approach is accurate and imposes a reasonable
communication load and level of power consumption.Comment: Extended version of a paper appearing in the Int'l Conference on
Distributed Computing Systems 200
Connecting competitor, stress-tolerator and ruderal (CSR) theory and Lund Potsdam Jena managed Land 5 (LPJmL 5) to assess the role of environmental conditions, management and functional diversity for grassland ecosystem functions
Forage offtake, leaf biomass and soil organic carbon storage are important ecosystem services of permanent grasslands, which are determined by climatic conditions, management and functional diversity. However, functional diversity is not independent of climate and management, and it is important to understand the role of functional diversity and these dependencies for ecosystem services of permanent grasslands, since functional diversity may play a key role in mediating impacts of changing conditions. Large-scale ecosystem models are used to assess ecosystem functions within a consistent framework for multiple climate and management scenarios. However, large-scale models of permanent grasslands rarely consider functional diversity. We implemented a representation of functional diversity based on the competitor, stress-tolerator and ruderal (CSR) theory and the global spectrum of plant form and function into the Lund Potsdam Jena managed Land (LPJmL) dynamic global vegetation model (DGVM) forming LPJmL-CSR. Using a Bayesian calibration method, we parameterised new plant functional types (PFTs) and used these to assess forage offtake, leaf biomass, soil organic carbon storage and community composition of three permanent grassland sites. These are a temperate grassland and a hot and a cold steppe for which we simulated several management scenarios with different defoliation intensities and resource limitations. LPJmL-CSR captured the grassland dynamics well under observed conditions and showed improved results for forage offtake, leaf biomass and/or soil organic carbon (SOC) compared to the original LPJmL 5 version at the three grassland sites. Furthermore, LPJmL-CSR was able to reproduce the trade-offs associated with the global spectrum of plant form and function, and similar strategies emerged independent of the site-specific conditions (e.g. the C and R PFTs were more resource exploitative than the SÂ PFT). Under different resource limitations, we observed a shift in the community composition. At the hot steppe, for example, irrigation led to a more balanced community composition with similar C, S and R PFT shares of aboveground biomass. Our results show that LPJmL-CSR allows for explicit analysis of the adaptation of grassland vegetation to changing conditions while explicitly considering functional diversity. The implemented mechanisms and trade-offs are universally applicable, paving the way for large-scale application. Applying LPJmL-CSR for different climate change and functional diversity scenarios may generate a range of future grassland productivities.</p
Public space in an age of austerity
Through an overview of the decade 2008 to 2017, and looking comparatively across four northern European cities, this
paper refects on the changing nature of public space during these austerity years and on the processes of shaping public
spaces. The paper draws from the experiences of London, Copenhagen, Malmo and Oslo to explore processes of the design,
development, use and management of public spaces during this period. The evidence suggests that we have witnessed a
period of signifcant innovation, side by side with major challenges to the collective approach to public spaces. This has
led to distinct forms of public spaces that for good or ill have multiplied as a result of the trends discussed in the paper,
spaces of; expectation; the private/public sphere; spectacle; respite; infrastructure; diversion; income generation; security;
the ephemeral city; community control; occupation; disadvantage; and decline. Episodes of changing practice are set out in
the paper and cumulatively reveal distinct and signifcant changes during the austerity era, although not necessarily in the
manner that might have been expected. Instead, in these four cities, the impact of austerity seems to have been eclipsed by
other evolving and competing public policy goals, and by the evolving range of public space type
Global Disease Burden Estimates of Respiratory Syncytial Virus–Associated Acute Respiratory Infection in Older Adults in 2015::A Systematic Review and Meta-Analysis
Respiratory syncytial virus associated acute respiratory infection (RSV-ARI)constitutes a substantial disease burden in older adults≥65 years. We aimed to identify all studies worldwide investigating the disease burden ofRSV-ARIin this population. We estimated thecommunityincidence, hospitalisationrate and in-hospital case fatality ratio (hCFR) of RSV-ARI in older adults stratified by industrialized anddeveloping regions, with data from a systematic review ofstudies published between January 1996 and April 2018, and from 8 unpublished population-based studies. We applied these rate estimates to population estimates for 2015, to calculate the global and regional burdenin older adults with RSV-ARIin community and in hospital duringthat year. We estimated thenumber ofin-hospital RSV-ARIdeaths by combining hCFR with hospital admission estimates from hospital-based studies. In 2015, there were about 1.5million(95% CI 0.3-6.9) episodes of RSV-ARIin older adults in41industrialised countries (data missing in developing countries), and of these 214,000 (~14.5%; 95% CI 100,000-459,000) were admitted to hospitals. The global number of hospital admissionsforRSV-ARI in older adults was estimated at 336,000 (UR 186,000-614,000).We further estimated about 14,000 (UR 5,000-50,000) in-hospital deaths related to RSV-ARIglobally.The hospital admission rate and hCFR were higher for those ≥65 years than those aged 50-64 years. The disease burden of RSV-ARIamong older adults is substantialwith limited data from developing countries; appropriate prevention and management strategiesare needed to reduce this burden
Climate change reduces extent of temperate drylands and intensifies drought in deep soils
Drylands cover 40% of the global terrestrial surface and provide important
ecosystem services. While drylands as a whole are expected to increase in
extent and aridity in coming decades, temperature and precipitation forecasts
vary by latitude and geographic region suggesting different trajectories for
tropical, subtropical, and temperate drylands. Uncertainty in the future of
tropical and subtropical drylands is well constrained, whereas soil moisture
and ecological droughts, which drive vegetation productivity and composition,
remain poorly understood in temperate drylands. Here we show that, over the
twenty first century, temperate drylands may contract by a third, primarily
converting to subtropical drylands, and that deep soil layers could be
increasingly dry during the growing season. These changes imply major shifts
in vegetation and ecosystem service delivery. Our results illustrate the
importance of appropriate drought measures and, as a global study that focuses
on temperate drylands, highlight a distinct fate for these highly populated
areas
Endometriosis and Headache
Headache and endometriosis show some similarities in their clinical and epidemiological features that are probably due to the influence of female sexual hormones on both disorders. Epidemiological studies indicate that they are comorbid disorders. However, the nature of the comorbidity is not known with certainty, but a likely explanation may be common susceptibility genes. Another possibility is that, because they both are related to pain, increased pain sensitivity induced by one of the disorders may lead to a higher likelihood of developing the other, possibly mediated by nitrogen oxide or prostaglandins. A common link to the widespread use of estroprogestins may seem less probable. For physicians dealing with women with either of these disorders, awareness of the comorbidity may be helpful in the treatment of the patient
- …