1,683 research outputs found
Exploratory Pollen Analysis of Hargrove Lake, Davy Crockett National Forest Houston County, Texas
The objectives of this exploratory pollen analysis of selected samples from a sediment core taken at Hargrove Lake, Davy Crockett National Forest, Houston County, Texas, are to ascertain the quality of pollen preservation in the lake bottom matrix and to evaluate the potential of the pollen spectra deposited in the lake for providing information about former environmental conditions on Davy Crockett National Forest. Hargrove Lake is a natural lake in the floodplain of the Neches River in Houston County, Texas. The Hargrove Lake site (41H0150) lies a short distance to the west. The lake is presently is surrounded by a 10m wide stand of buttonbush (Cephalanthus). These plants are three m tall and have two to ten em diameter trunks. A woodland dominated by water oaks (Quercus nigra) and sweetgum (Liquidambar styraciflua) lies beyond the button bush. These trees are 30 to 40 m tall, and the woodland canopy is 90 to 98 percent closed. The lake is normally about 50 m wide by 200 m long, giving it a normal surface area of approximately 2.5 hectares. The mean depth of the lake at high water is about 90 em. Bedrock marl underlies the area, and the lake retains water during even the most severe droughts. It should provide a continuous pollen deposition record
Aspirin and glyceryl trinitrate effects on polyamine uptake and smooth muscle cell growth
This paper looks at aspirin and glyceryl trinitrate effects on polyamine uptake and smooth muscle cell growt
Pollen Record Formation Processes at the Isles of Shoals: Botanical Records of Human Behavior
Exploratory pollen analysis on Appledore Island at the Isles of Shoals, a group of nine islands located approximately eight miles off the coast of southern Maine and New Hampshire, indicates that pollen preservation is excellent in exposed island soil deposits in the temperate zone and that pollen percolation into deposits from surface preserves the record of natural and cultural events where dep cultural deposits have not developed. The Appledore pollen spectra registered the establishment of the resort hotel industry on the island in the mid-19th-century, the virtual abandonment of the island after a major fire in 1914, and the chestnut blight of ca. 1925 on the mainland. The high rate of pollen percolation, ca. 1 cm in 4.2 years, in the loose, organic soils and the shallow deposits on the island limit the palynological land-use record in exposed soils to ca. 175 years. Because pollen is protected from leaching by large flat stones, evidence for 17th-, 18th-, and early 19th-century land use should be recovered by seriating pollen proflies taken from under surface-laid foundation stones and from under foundation stones cast down during dismantling of structures
The Use of Opal Phytolith Analysis in a Comprehensive Environmental Study: An Example from 19th-Century Lowell, Massachusetts
The value of opal phytolith analysis is demonstrated in a comprehensive environmental study of a historical site, the Kirk Street Agents\u27 House, Lowell, Massachusett. A method to measure phytolith degradation percentages is tested and shown to yield similar results to pollen corrosion indices; further research on this new method is suggested, however. Fluctuations in two classes of grass phytoliths indicate changing environmental conditions that support and expand upon changes noted in the pollen spectra. The results of the phytolith analysis are integrated with information derived from documentary research, artifactual analysis, stratigraphic interpretation, and other ethnobotanical methods to arrive at conclusions based on a truly multicomponent strategy. All lines of evidence point to a series of discrete occupational episode at the Kirk Street Agents\u27 House coupled with con-comitant changes in the use of yard space
Four Historical Landscapes of the Merchantâs House Museum Backlot, Manhattan Island, New York, Identified through Pollen Analysis
The Merchantâs House Museum is on Manhattan Island in New York City, at 29 East Fourth Street, between Lafayette Street and the Bowery. It is the sole, remaining, intact 19th-century family home in the city with original, period furnishings. An archaeological study of the Merchantâs House backyard was undertaken in 1991â1995 in conjunction with an historical-structure study of the house. This pollen analysis of a soil profile from a central parterre was part of the backlot study
Battlefield Palynology: Reinterpretation of British Earthworks, Saratoga National Historical Park, Stillwater, New York
Pollen analysis was done on a core through a linear mound formerly identified as a 1777 British earthwork at Saratoga National Historical Park. Documents indicate that the British earthwork was built in a forest in a sparsely settled region. Pollen data record a 71-year reforestation sequence under the mound, indicating that it cannot be a Revolutionary War earthwork
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Chromatin accessibility underlies synthetic lethality of SWI/SNF subunits in ARID1A-mutant cancers.
ARID1A, a subunit of the SWI/SNF chromatin remodeling complex, is frequently mutated in cancer. Deficiency in its homolog ARID1B is synthetically lethal with ARID1A mutation. However, the functional relationship between these homologs has not been explored. Here, we use ATAC-seq, genome-wide histone modification mapping, and expression analysis to examine colorectal cancer cells lacking one or both ARID proteins. We find that ARID1A has a dominant role in maintaining chromatin accessibility at enhancers, while the contribution of ARID1B is evident only in the context of ARID1A mutation. Changes in accessibility are predictive of changes in expression and correlate with loss of H3K4me and H3K27ac marks, nucleosome spacing, and transcription factor binding, particularly at growth pathway genes including MET. We find that ARID1B knockdown in ARID1A mutant ovarian cancer cells causes similar loss of enhancer architecture, suggesting that this is a conserved function underlying the synthetic lethality between ARID1A and ARID1B
ABAEnrichment: An R package to test for gene set expression enrichment in the adult and developing human brain
Summary: We present ABAEnrichment, an R package that tests for expression enrichment in specific brain regions at different developmental stages using expression information gathered from multiple regions of the adult and developing human brain, together with ontologically organized structural information about the brain, both provided by the Allen Brain Atlas. We validate ABAEnrichment by successfully recovering the origin of gene sets identified in specific brain cell-types and developmental stages. Availability and Implementation: ABAEnrichment was implemented as an R package and is available under GPL (âĽâ2) from the Bioconductor website (http://bioconductor.org/packages/3.3/bioc/html/ABAEnrichment.html). Contacts: [email protected], [email protected] or [email protected] Supplementary information: Supplementary data are available at Bioinformatics online
The Pollen Record Formation Processes of a Rural Cellar Fill: Identification of the Captain Brown House, Concord, Massachusetts
Captain David Brown was a major participant in the April 19, 1775 skirmish at the North Bridge, Concord, Massachusetts, and his house stood very close to the battlefield. Diary entries record that his house was dismantled in 1868 and that the filling of the cellar hole began on October 16th of the same year. Archaeologists uncovered the cellars of two houses on the David Brown property: one cellar fill contained only probable 18th-century artifacts; the second contained 18th- to mid-19th-century artifacts. Pollen data indicating that the second cellar hole was filled in the fall link that cellar hole to diary entries, confirming the identification of the structure as the David Brown house
Chaotic exploration and learning of locomotion behaviours
We present a general and fully dynamic neural system, which exploits intrinsic chaotic dynamics, for the real-time goal-directed exploration and learning of the possible locomotion patterns of an articulated robot of an arbitrary morphology in an unknown environment. The controller is modeled as a network of neural oscillators that are initially coupled only through physical embodiment, and goal-directed exploration of coordinated motor patterns is achieved by chaotic search using adaptive bifurcation. The phase space of the indirectly coupled neural-body-environment system contains multiple transient or permanent self-organized dynamics, each of which is a candidate for a locomotion behavior. The adaptive bifurcation enables the system orbit to wander through various phase-coordinated states, using its intrinsic chaotic dynamics as a driving force, and stabilizes on to one of the states matching the given goal criteria. In order to improve the sustainability of useful transient patterns, sensory homeostasis has been introduced, which results in an increased diversity of motor outputs, thus achieving multiscale exploration. A rhythmic pattern discovered by this process is memorized and sustained by changing the wiring between initially disconnected oscillators using an adaptive synchronization method. Our results show that the novel neurorobotic system is able to create and learn multiple locomotion behaviors for a wide range of body configurations and physical environments and can readapt in realtime after sustaining damage
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