74 research outputs found
Geomorphic evolution and the role of organic matter in a temperate supratidal Melaleuca wetland: Corner Inlet, VIC
Coastal wetlands are highly productive ecosystems with an exceptional capacity for sequestering organic matter in the accumulating substrate. Recent studies have focused on intertidal saltmarsh and mangrove communities with limited research extending to the supratidal wetland forests, especially in temperature regions. The overall aim to fill the knowledge gap present in current literature by addressing two aims. The aims of this study is to (1) determine the processes driving the development and persistence of supratidal wetland forests in Corner Inlet, Victoria, Australia; and (2) reconstruct the historic vegetation shifts that have occurred in the embayment over the Holocene. A combination of stratigraphic analyses and photogrammetry were used to achieve these aim. Cores were collected to quantify the accumulation and preservation of organic matter across the intertidal-supratidal wetland gradient. Results from stratigraphic logs, bulk density and loss-on-ignition analyses, grain size, and high-resolution core logging (ITRAX) were compiled to determine the contribution and preservation capacity of organic matter in Melaleuca paperbark swamps (MPS) and to produce a paleo-reconstruction of the site. Along the study gradient, an increase in organic matter contribution was observed within the surface organic horizon shifting from the mangrove (5-10% organic matter) through to the MPS communities (up to 66% organic matter). The organic-rich soils of MPS noticeably declined at a greater rate in the more terrestrial substrate further from the seaward edge. This revealed a limitation in the preservation capacity of MPS with depth, with MPS having a greater effectiveness in organic preservation in more marine influenced settings. A time series analysis of historic aerial imagery, and paleo-reconstruction of sedimentary cores were used to reconstruct the historic vegetation shifts across the intertidal-supratidal wetland complex. Seaward migration of the wetland communities was identified during the paleo-reconstruction. Overtime, the infilling estuary revealed marine sands and seagrass meadows shift progressively to mangrove, saltmarsh, herbaceous wetlands and finally MPS. However, recent decadal shifts in the wetland community have inverted to a landward retreat. These results suggest that anthropogenic impacts on the Earth’s climate have increased the rate of sea-level rise to a point which exceeds the rate of vertical accretion. The landward retreat of MPS and related rise in sea-level may result in the belowground disruption of preserved organic matter. This may lead to alterations in the global carbon cycle with large proportion of organic matter sequestered in these forests to be remineralised into CO2, having further implications on anthropogenic climate change
Experimental Study of Heat Release Effects in Exothermically Reacting Turbulent Shear Flows.
Comparisons are presented from the first
inner-scaled measurements of velocity gradient quantities in reacting and
nonreacting versions of otherwise identical turbulent shear flows. Distributions
of gradient quantities are obtained for outer-scale Reynolds numbers
from 7200 to 200,000. The local outer length and velocity scales and associated inner
scaling are used to identify the dominant physical mechanisms that produce
heat release effects on the inner scales. In the nonreacting cases, classical
inner scaling with the viscosity and inner (viscous) length scale
removes most differences in distributions measured at different Reynolds numbers, with remaining
differences being due to incomplete resolution with increasing Reynolds number.
Inertial and dissipation range spectra allow the measurement resolution
scale and the proper resolution-corrected
inner scaling to be determined, with the resulting scaling verifying near-perfect
similarity for all Reynolds numbers. In the reacting cases, departures from this
similarity reveal the true inner-scale changes due to heat release. Results
clearly show that when inertial and body force effects on the outer length and velocity scales are accounted
for via the equivalent density, and viscous effects are accounted
for via the mixture-fraction-averaged viscosity, the resolution-corrected
inner scaling reveals remaining effects of heat release on turbulent shear
flows to be remarkably small.
Using the same resolution-corrected inner scaling, further experiments were conducted under conditions of
nonzero mean shear. Accounting for the effects of classical external intermittency, results
from the velocity gradient distributions indicate
a small effect of nonzero mean shear at the finest scales of the flow. This
is corroborated by evaluation of the Corrsin-Uberoi
criteria, where the present results satisfy the
condition for all of the measured reacting and nonreacting cases.
Use of the resolution-corrected inner scaling permits direct comparison between otherwise identical
turbulent shear flows; the present results reveal that the combined effects of heat release and mean shear on
the inner-scales of turbulent shear flows are relatively small.Ph.D.Aerospace EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/57637/2/nagelz_1.pd
Inter-individual variation in DNA repair capacity: A need for multi-pathway functional assays to promote translational DNA repair research
Why does a constant barrage of DNA damage lead to disease in some individuals, while others remain healthy? This article surveys current work addressing the implications of inter-individual variation in DNA repair capacity for human health, and discusses the status of DNA repair assays as potential clinical tools for personalized prevention or treatment of disease. In particular, we highlight research showing that there are significant inter-individual variations in DNA repair capacity (DRC), and that measuring these differences provides important biological insight regarding disease susceptibility and cancer treatment efficacy. We emphasize work showing that it is important to measure repair capacity in multiple pathways, and that functional assays are required to fill a gap left by genome wide association studies, global gene expression and proteomics. Finally, we discuss research that will be needed to overcome barriers that currently limit the use of DNA repair assays in the clinic
Western Gulf of Maine Bathymetry and Backscatter Synthesis
In July 2014 a Cooperative Agreement between the Bureau of Ocean Energy Management, the University of New Hampshire Center for Coastal and Ocean Mapping, and the New Hampshire Geological Survey was developed to assess the potential sand and gravel resources on the New Hampshire shelf and vicinity for the primary purpose of beach nourishment to enhance coastal resiliency. Of major importance to the effort was the development of high resolution bathymetric maps of the region to provide an understanding of the seafloor and to be used as a base for subsequent mapping products. Fortunately, over the last decade a number of high resolution multibeam echosounder bathymetric surveys were completed in the Western Gulf of Maine including the New Hampshire shelf. In addition, many of these multibeam echosounder surveys collected backscatter, which is the intensity of the returned acoustic signal from the seafloor and often reveals a great deal of information about the characteristics of the substrate.
Utilizing the high resolution multibeam echosounder bathymetry, as well as several older extant surveys, a synthesis was constructed for the Western Gulf of Maine. The original surveys used in this compilation were gridded over a large range (0.50 to 25 m). Therefore, the surveys were re-gridded at 4 m and 8 m for map development. Composites were also constructed of multibeam echosounder backscatter for the Western Gulf of Maine (gridded at 2m). However, due to the difficulties of combining varying surveys, the synthesis for the backscatter surveys was limited to a region off New Hampshire
BLOOM: A 176B-Parameter Open-Access Multilingual Language Model
Large language models (LLMs) have been shown to be able to perform new tasks
based on a few demonstrations or natural language instructions. While these
capabilities have led to widespread adoption, most LLMs are developed by
resource-rich organizations and are frequently kept from the public. As a step
towards democratizing this powerful technology, we present BLOOM, a
176B-parameter open-access language model designed and built thanks to a
collaboration of hundreds of researchers. BLOOM is a decoder-only Transformer
language model that was trained on the ROOTS corpus, a dataset comprising
hundreds of sources in 46 natural and 13 programming languages (59 in total).
We find that BLOOM achieves competitive performance on a wide variety of
benchmarks, with stronger results after undergoing multitask prompted
finetuning. To facilitate future research and applications using LLMs, we
publicly release our models and code under the Responsible AI License
Global burden of 369 diseases and injuries in 204 countries and territories, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019
Background: In an era of shifting global agendas and expanded emphasis on non-communicable diseases and injuries along with communicable diseases, sound evidence on trends by cause at the national level is essential. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) provides a systematic scientific assessment of published, publicly available, and contributed data on incidence, prevalence, and mortality for a mutually exclusive and collectively exhaustive list of diseases and injuries. Methods: GBD estimates incidence, prevalence, mortality, years of life lost (YLLs), years lived with disability (YLDs), and disability-adjusted life-years (DALYs) due to 369 diseases and injuries, for two sexes, and for 204 countries and territories. Input data were extracted from censuses, household surveys, civil registration and vital statistics, disease registries, health service use, air pollution monitors, satellite imaging, disease notifications, and other sources. Cause-specific death rates and cause fractions were calculated using the Cause of Death Ensemble model and spatiotemporal Gaussian process regression. Cause-specific deaths were adjusted to match the total all-cause deaths calculated as part of the GBD population, fertility, and mortality estimates. Deaths were multiplied by standard life expectancy at each age to calculate YLLs. A Bayesian meta-regression modelling tool, DisMod-MR 2.1, was used to ensure consistency between incidence, prevalence, remission, excess mortality, and cause-specific mortality for most causes. Prevalence estimates were multiplied by disability weights for mutually exclusive sequelae of diseases and injuries to calculate YLDs. We considered results in the context of the Socio-demographic Index (SDI), a composite indicator of income per capita, years of schooling, and fertility rate in females younger than 25 years. Uncertainty intervals (UIs) were generated for every metric using the 25th and 975th ordered 1000 draw values of the posterior distribution. Findings: Global health has steadily improved over the past 30 years as measured by age-standardised DALY rates. After taking into account population growth and ageing, the absolute number of DALYs has remained stable. Since 2010, the pace of decline in global age-standardised DALY rates has accelerated in age groups younger than 50 years compared with the 1990–2010 time period, with the greatest annualised rate of decline occurring in the 0–9-year age group. Six infectious diseases were among the top ten causes of DALYs in children younger than 10 years in 2019: lower respiratory infections (ranked second), diarrhoeal diseases (third), malaria (fifth), meningitis (sixth), whooping cough (ninth), and sexually transmitted infections (which, in this age group, is fully accounted for by congenital syphilis; ranked tenth). In adolescents aged 10–24 years, three injury causes were among the top causes of DALYs: road injuries (ranked first), self-harm (third), and interpersonal violence (fifth). Five of the causes that were in the top ten for ages 10–24 years were also in the top ten in the 25–49-year age group: road injuries (ranked first), HIV/AIDS (second), low back pain (fourth), headache disorders (fifth), and depressive disorders (sixth). In 2019, ischaemic heart disease and stroke were the top-ranked causes of DALYs in both the 50–74-year and 75-years-and-older age groups. Since 1990, there has been a marked shift towards a greater proportion of burden due to YLDs from non-communicable diseases and injuries. In 2019, there were 11 countries where non-communicable disease and injury YLDs constituted more than half of all disease burden. Decreases in age-standardised DALY rates have accelerated over the past decade in countries at the lower end of the SDI range, while improvements have started to stagnate or even reverse in countries with higher SDI. Interpretation: As disability becomes an increasingly large component of disease burden and a larger component of health expenditure, greater research and developm nt investment is needed to identify new, more effective intervention strategies. With a rapidly ageing global population, the demands on health services to deal with disabling outcomes, which increase with age, will require policy makers to anticipate these changes. The mix of universal and more geographically specific influences on health reinforces the need for regular reporting on population health in detail and by underlying cause to help decision makers to identify success stories of disease control to emulate, as well as opportunities to improve. Funding: Bill & Melinda Gates Foundation. © 2020 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licens
Global age-sex-specific fertility, mortality, healthy life expectancy (HALE), and population estimates in 204 countries and territories, 1950-2019 : a comprehensive demographic analysis for the Global Burden of Disease Study 2019
Background: Accurate and up-to-date assessment of demographic metrics is crucial for understanding a wide range of social, economic, and public health issues that affect populations worldwide. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 produced updated and comprehensive demographic assessments of the key indicators of fertility, mortality, migration, and population for 204 countries and territories and selected subnational locations from 1950 to 2019.
Methods: 8078 country-years of vital registration and sample registration data, 938 surveys, 349 censuses, and 238 other sources were identified and used to estimate age-specific fertility. Spatiotemporal Gaussian process regression (ST-GPR) was used to generate age-specific fertility rates for 5-year age groups between ages 15 and 49 years. With extensions to age groups 10–14 and 50–54 years, the total fertility rate (TFR) was then aggregated using the estimated age-specific fertility between ages 10 and 54 years. 7417 sources were used for under-5 mortality estimation and 7355 for adult mortality. ST-GPR was used to synthesise data sources after correction for known biases. Adult mortality was measured as the probability of death between ages 15 and 60 years based on vital registration, sample registration, and sibling histories, and was also estimated using ST-GPR. HIV-free life tables were then estimated using estimates of under-5 and adult mortality rates using a relational model life table system created for GBD, which closely tracks observed age-specific mortality rates from complete vital registration when available. Independent estimates of HIV-specific mortality generated by an epidemiological analysis of HIV prevalence surveys and antenatal clinic serosurveillance and other sources were incorporated into the estimates in countries with large epidemics. Annual and single-year age estimates of net migration and population for each country and territory were generated using a Bayesian hierarchical cohort component model that analysed estimated age-specific fertility and mortality rates along with 1250 censuses and 747 population registry years. We classified location-years into seven categories on the basis of the natural rate of increase in population (calculated by subtracting the crude death rate from the crude birth rate) and the net migration rate. We computed healthy life expectancy (HALE) using years lived with disability (YLDs) per capita, life tables, and standard demographic methods. Uncertainty was propagated throughout the demographic estimation process, including fertility, mortality, and population, with 1000 draw-level estimates produced for each metric. Findings: The global TFR decreased from 2·72 (95% uncertainty interval [UI] 2·66–2·79) in 2000 to 2·31 (2·17–2·46) in 2019. Global annual livebirths increased from 134·5 million (131·5–137·8) in 2000 to a peak of 139·6 million (133·0–146·9) in 2016. Global livebirths then declined to 135·3 million (127·2–144·1) in 2019. Of the 204 countries and territories included in this study, in 2019, 102 had a TFR lower than 2·1, which is considered a good approximation of replacement-level fertility. All countries in sub-Saharan Africa had TFRs above replacement level in 2019 and accounted for 27·1% (95% UI 26·4–27·8) of global livebirths. Global life expectancy at birth increased from 67·2 years (95% UI 66·8–67·6) in 2000 to 73·5 years (72·8–74·3) in 2019. The total number of deaths increased from 50·7 million (49·5–51·9) in 2000 to 56·5 million (53·7–59·2) in 2019. Under-5 deaths declined from 9·6 million (9·1–10·3) in 2000 to 5·0 million (4·3–6·0) in 2019. Global population increased by 25·7%, from 6·2 billion (6·0–6·3) in 2000 to 7·7 billion (7·5–8·0) in 2019. In 2019, 34 countries had negative natural rates of increase; in 17 of these, the population declined because immigration was not sufficient to counteract the negative rate of decline. Globally, HALE increased from 58·6 years (56·1–60·8) in 2000 to 63·5 years (60·8–66·1) in 2019. HALE increased in 202 of 204 countries and territories between 2000 and 2019
Fluorescence Sheds Light on DNA Damage, DNA Repair, and Mutations
© 2020 Elsevier Inc. DNA damage can lead to carcinogenic mutations and toxicity that promotes diseases. Therefore, having rapid assays to quantify DNA damage, DNA repair, mutations, and cytotoxicity is broadly relevant to health. For example, DNA damage assays can be used to screen chemicals for genotoxicity, and knowledge about DNA repair capacity has applications in precision prevention and in personalized medicine. Furthermore, knowledge of mutation frequency has predictive power for downstream cancer, and assays for cytotoxicity can predict deleterious health effects. Tests for all of these purposes have been rendered faster and more effective via adoption of fluorescent readouts. Here, we provide an overview of established and emerging cell-based assays that exploit fluorescence for studies of DNA damage and its consequences
- …