11,009 research outputs found
Recommended from our members
Assessing the preservation of cytosine methylation in ancient DNA from five prehistoric Native American populations
textCytosine methylation of CpG dinucleotides is an important epigenetic mark that regulates gene expression in humans. While methylation patterns in extant populations have been widely studied, few studies have attempted to analyze methylation in ancient DNA. Indeed, it was only recently shown that methyl groups can be preserved in ancient DNA. However, it is unknown how often methylation patterns can be recovered from ancient samples with preserved nuclear DNA. If they are frequently preserved, it may ultimately be possible to infer patterns of gene activity at the population level in ancient times. In this study, I assessed the preservation of cytosine methylation in ancient DNA from the remains of 30 prehistoric Native Americans from California, Illinois, Kentucky, and Mexico. These samples were previously shown to contain endogenous mitochondrial and nuclear DNA. I analyzed the cytosine methylation states of CpG-rich retrotransposons, which are epigenetically inactivated by cytosine methylation in humans. Unmethylated cytosines were converted to uracils by treatment with sodium bisulfite. Bisulfite products were pyrosequenced, and C-to-T conversions at potentially methylated CpG dinucleotides were quantified. I found that cytosine methylation is readily recoverable from human remains with preserved nuclear DNA from various localities over the time depth tested (~6000 years). This study presents the first direct evidence of cytosine methylation in ancient human remains, and suggests that it may be possible to analyze patterns of gene activity in ancient populations.Anthropolog
Marshall Avionics Testbed System (MAST)
Work accomplished in the summer of 1989 in association with the NASA/ASEE Summer Faculty Research Fellowship Program at Marshall Space Flight Center is summarized. The project was aimed at developing detailed specifications for the Marshall Avionics System Testbed (MAST). This activity was to include the definition of the testbed requirements and the development of specifications for a set of standard network nodes for connecting the testbed to a variety of networks. The project was also to include developing a timetable for the design, implementation, programming and testing of the testbed. Specifications of both hardware and software components for the system were to be included
Navigating public health chemicals policy in Australia: a policy makerâs and practitionerâs guide
Chemicals are ubiquitous in everyday life. Environmental health practitioners rely on a complex web of regulators and policy bodies to ensure the protection of public health, yet few understand the full extent of this web. A lack of understanding can hamper public health response and impede policy development. In this paper we map the public health chemicals policy landscape in Australia and conclude that an understanding of this system is essential for effective environmental health responses and policy development.
NSW Public Health Bulletin 23(12) 217-227 http://dx.doi.org/10.1071/NB1211
New Distribution Records for Minnesota Odonata
Several Minnesota state record Odonata, Aeshna subarctica, Ophiogomphus anomalus, Stylogomphus albistylus, Stylurus scudderi, and Coenagrion interrogatum are reported, along with notes on the distribution and habitat of Aeshna sitchensis. New county records for Minnesota Odonata are also reported
B-mode CMB Polarization from Patchy Screening during Reionization
B-modes in CMB polarization from patchy reionization arise from two effects:
generation of polarization from scattering of quadrupole moments by
reionization bubbles, and fluctuations in the screening of E-modes from
recombination. The scattering contribution has been studied previously, but the
screening contribution has not yet been calculated. We show that on scales
smaller than the acoustic scale (l>300), the B-mode power from screening is
larger than the B-mode power from scattering. The ratio approaches a constant
~2.5 below the damping scale (l>2000). On degree scales relevant for
gravitational waves (l<100), screening B-modes have a white noise tail and are
subdominant to the scattering effect. These results are robust to uncertainties
in the modeling of patchy reionization.Comment: 4 pages, 1 figure; minor changes matching PRD published versio
Electrochemistry of 2,2'-Bipyridine Complexes of Cobalt in the Presence of Acrylonitrile
The previously claimed (1) catalysis of the electroreduction of acrylonitrile by means of a complex of Co(I) and 2,2â˛âbipyridine is shown to be erroneous. The âcatalytic currentsâ result instead from the twoâelectron reduction of a mixed complex of Co(I) acrylonitrile and 2,2â˛âbipyridine. The equilibrium and forward rate constants for the formation of the mixed complex have been estimated and its spectrum is given. The behavior of a number of other vinyl monomers, which mimic acrylonitrile, is described
Monthly progress report
This report is the mid-year report intended for the design concepts for the communication network for the Advanced Solid Rocket Motor (ASRM) facility being built at Yellow Creek near Iuka, MS. The overall network is to include heterogeneous computers, to use various protocols, and to have different bandwidths. Performance consideration must be given to the potential network applications in the network environment. The performance evaluation of X window applications was given the major emphasis in this report. A simulation study using Bones will be included later. This mid-year report has three parts: Part 1 is an investigation of X window traffic using TCP/IP over Ethernet networks; part 2 is a survey study of performance concepts of X window applications with Macintosh computers; and the last part is a tutorial on DECnet protocols. The results of this report should be useful in the design and operation of the ASRM communication network
Agronomic practices to improve or maintain the protein content of high yielding, long season wheats.
Trial 90SG8, 90SG9, 90ES9, 90ES11, 90MT8, 90KO2
Wheat variety * Time of sowing
Location: Salmon Gums Research Station, Mt. Ridley, East Gibson, Mt Barker Research Station, Kojaneerup Research Station
The aim is to define the optimum heading/flowering date on the South Coast. This trial also provides information on the performance of the varieties and new cross-breds at various sowing times.
Trial 90E10, 90ES12, 90ES13, 90ES14, 90ES15, 90ES16, 90SG10, 90SG11, 90MT10, 90KO3, 90KO4
Wheat protein on the South Coast
Location: Esperance Downs Research Station, Gibson, Neridup, Mt Ridley, Salmon Gums Research Station, Mt Barker Research Station, Kojaneerup Research Station
The Australian Wheat Board is concerned at the decline of grain protein in wheat throughout Australia, especially in the high rainfall areas. This project is examining means of increasing grain protein under high yielding conditions by understanding the influence of rotation (root disease), time of sowing, and nitrogen application.
Trial 90ES10
Wheat variety * Time of sowing.
Location: Neridup,
The aim is to define the optimum heading/flowering date on the South Coast. This trial also provides information on the performance of the varieties and new cross-breds at various sowing times
- âŚ