A late-Holocene pollen record from Lower Pahrangat Lake, southern Nevada, USA: high resolution paleoclimatic records and analysis of environmental responses to climate change

EXTRACT (SEE PDF FOR FULL ABSTRACT): High resolution paleobotanical records provide sufficient detail to correlate events regionally. Once correlated events can be examined in tandem to determine the underlying inputs that fashioned them. Several localities in the Great Basin have paleobotanical records of sufficient detail to generate regional reconstructions of vegetation changes for the last 2 ka and provide conclusions as to the climates that caused them

A detailed 2,000-year late-Holocene pollen record from Lower Pahranagat Lake, southern Nevada, USA [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): Preliminary analysis of 128 pollen samples and 7 radiocarbon dates from a 5-meter-long, 10-centimeter-diameter sediment core retrieved from Lower Pahranagat Lake (elevation 975 meters), Lincoln County, Nevada, gives us a rare, continuous record of vegetation change at 14-year intervals over the past 2,000 years

Proceedings, Western juniper management short course, October 15-16, 1984, Bend, Oregon

Published 1984. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo

Interaction of language, auditory and memory brain networks in auditory verbal hallucinations

Auditory verbal hallucinations (AVH) occur in psychotic disorders, but also as a symptom of other conditions and even in healthy people. Several current theories on the origin of AVH converge, with neuroimaging studies suggesting that the language, auditory and memory/limbic networks are of particular relevance. However, reconciliation of these theories with experimental evidence is missing. We review 50 studies investigating functional (EEG and fMRI) and anatomic (diffusion tensor imaging) connectivity in these networks, and explore the evidence supporting abnormal connectivity in these networks associated with AVH. We distinguish between functional connectivity during an actual hallucination experience (symptom capture) and functional connectivity during either the resting state or a task comparing individuals who hallucinate with those who do not (symptom association studies). Symptom capture studies clearly reveal a pattern of increased coupling among the auditory, language and striatal regions. Anatomical and symptom association functional studies suggest that the interhemispheric connectivity between posterior auditory regions may depend on the phase of illness, with increases in non-psychotic individuals and first episode patients and decreases in chronic patients. Leading hypotheses involving concepts as unstable memories, source monitoring, top-down attention, and hybrid models of hallucinations are supported in part by the published connectivity data, although several caveats and inconsistencies remain. Specifically, possible changes in fronto-temporal connectivity are still under debate. Precise hypotheses concerning the directionality of connections deduced from current theoretical approaches should be tested using experimental approaches that allow for discrimination of competing hypotheses

Viewpoint: Lessons From the Past For Managing Tomorrow's Range Ecosystems

This material was digitized as part of a cooperative project between the Society for Range Management, the National Agricultural Library, and the University of Arizona Libraries.The Rangelands archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform March 202

A Middle Holocene Radiocarbon Date and the Geologic Context of Human Occupation in the Tulare Lake Basin of California

In September 2001, during the course of an archaeological project on the western shore of Tulare Lake in Kings County, California, a human proximal phalanx of the left first digit of an adult of indeterminate sex was found in the wall of an irrigation canal in the Tulare Lake Basin, at a depth of ca. 180 cm. below the surface. The bone was subsequently radiocarbon dated to 4,360 ± 70 RCYBP (cal BP 5,270 to 5,170), making it the first human bone from the lake basin to be dated in this manner, and thereby adding to the sparse radiometric data base for Middle Holocene sites in the San Joaquin Valley. As an integral part of the cultural study, the geologic assessment of the project area demonstrated that intact archaeological deposits in this area of the lake basin would likely occur some distance west of the present 190-ft. elevation. Such deposits would also lie several feet below younger alluvial fan deposits

A Middle Holocene Radiocarbon Date and the Geologic Context of Human Occupation in the Tulare Lake Basin of California

In September 2001, during the course of an archaeological project on the western shore of Tulare Lake in Kings County, California, a human proximal phalanx of the left first digit of an adult of indeterminate sex was found in the wall of an irrigation canal in the Tulare Lake Basin, at a depth of ca. 180 cm. below the surface. The bone was subsequently radiocarbon dated to 4,360 ± 70 RCYBP (cal BP 5,270 to 5,170), making it the first human bone from the lake basin to be dated in this manner, and thereby adding to the sparse radiometric data base for Middle Holocene sites in the San Joaquin Valley. As an integral part of the cultural study, the geologic assessment of the project area demonstrated that intact archaeological deposits in this area of the lake basin would likely occur some distance west of the present 190-ft. elevation. Such deposits would also lie several feet below younger alluvial fan deposits

Late Holocene paleoenvironmental changes in the Seal Beach wetland (California, USA): A micropaleontological perspective

Pollen, benthic foraminifera, diatoms, sediment grain size, and organic matter content from a 230-cm long-AMS dated sediment core (Core SB-51B) were used to reconstruct paleoenvironmental changes and paleoclimatic evolution within the Seal Beach wetland (southern California, USA), during the last ~ 2000 years. A Q-mode cluster analysis based on diatom and foraminiferal data identified three distinct units: 1) the lowest sandy to silty-sand unit deposited before 1838 cal years BP (230 –140 cm in depth) is devoid of microfossils; 2) a clay rich intermediate unit dated between 1838 and 513 cal years BP (140–52 cm) is dominated by brackish and brackish-marine diatoms and foraminifera; and 3) a clay-rich zone deposited after 513 cal years BP(52 cm to the surface) contains high salt marsh adapted microfossils. Fresh-water and salt-tolerant diatoms from Unit 2 indicated several fresh-water influx events at 105 cm, 82 cm, and 75 cm possibly from a nearby stream. A shift from saltmarsh plants to terrestrial plants was inferred by pollen analysis. Throughout the record, the pine pollen increases suggest a shift towards cooler and wetter conditions during the last 300 years. Regional pollen records support our findings indicating a trend from drier conditions during the last 1800 years to the cooler, more mesic conditions of the Little Ice Age. The analyzed sedimentary sequence indicated the possible occurrence of three seismic events during the Late Holocene: E3 and E2 before 1760 cal years BP and E1, which took place just prior to 390 cal years BP

Evidence for a Long-Lived Pleistocene Lake, Carrizo Plain, California

Two recently obtained cores provide evidence of a long-lived lake that occupied the Carrizo Plain during the Pleistocene. Both cores come from an elevation of 584 masl on a portion of the former lake floor that was abandoned during the Holocene. The longer of the two cores (~42 m) has been sampled for a variety of analytical studies (e.g., palynology, isotopic chemistry, environmental magnetism, and SEM-petrography). The magnetic susceptibility signal contains two notable features corresponding to lithologies consistent with reducing conditions. The higher of these features occurs near the surface, the lower at ~18 m depth. A 14C date on charcoal from the upper reduced zone places the top of this zone at no older than 17.74 0.330 14C ka (20.24-22.00 cal ka). This date is consistent with OSL dates on geomorphic features associated with a highstand at 595 masl. The youngest age of the highstand shoreline was constrained by an OSL date of 16.7 ka from the top of the corresponding clay dune. Assuming that reducing conditions correspond to deep water, the new 14C date suggests that the upper reduced zone represents a Stage 2 pluvial maximum lake in the Carrizo Plain. If the lower reduced zone has a similar origin, then the Carrizo Plain has held a lake since well before Stage 6 time. This implication substantially extends the time interval of lacustrine deposition on the floor of the Carrizo Plain and, therefore, the time since the basin lost external drainage. The present lake floor is tilted due to deformation likely associated with the nearby San Andreas Fault. The lake sediment cores were taken from a surface above the present lake (582 masl) presumably abandoned by this tilting sometime after the maximum highstand. Thus, any record of Holocene deposition, if it ever existed at either core site, has been lost, probably by deflation