Varve formation during the past three centuries in three large proglacial lakes in south-central Alaska

2017 ◽  
Vol 130 (5-6) ◽  
pp. 757-774 ◽  
Author(s):  
Evelien Boes ◽  
Maarten Van Daele ◽  
Jasper Moernaut ◽  
Sabine Schmidt ◽  
Britta J.L. Jensen ◽  
...  
Keyword(s):  
The Past ◽  
South Central ◽  
Proglacial Lakes

scholarly journals Mitochondrial Genome Diversity in the Central Siberian Plateau with Particular Reference to Prehistory of Northernmost Eurasia

2019 ◽  
Author(s):  
S. V. Dryomov ◽  
A. M. Nazhmidenova ◽  
E. B. Starikovskaya ◽  
S. A. Shalaurova ◽  
N. Rohland ◽  
...  
Keyword(s):  
Geographic Area ◽  
Mtdna Sequences ◽  
The Past ◽  
South Central ◽  
Sayan Region ◽  
History Of ◽  
Mitochondrial Genome Diversity ◽  
The Last Glacial Maximum ◽  
Complete Mtdna ◽  
The Last Glacial

AbstractThe Central Siberian Plateau was last geographic area in Eurasia to become habitable by modern humans after the Last Glacial Maximum (LGM). Through comprehensive mitochondrial DNA genomes retained in indigenous Siberian populations, the Ket, Tofalar, and Todzhi - we explored genetic links between the Yenisei-Sayan region and Northeast Eurasia over the last 10,000 years. Accordingly, we generated 218 new complete mtDNA sequences and placed them into compound phylogenies along with 7 newly obtained and 70 published ancient mt genomes. Our findings reflect the origins and expansion history of mtDNA lineages that evolved in South-Central Siberia, as well as multiple phases of connections between this region and distant parts of Eurasia. Our result illustrates the importance of jointly sampling modern and prehistoric specimens to fully measure the past genetic diversity and to reconstruct the process of peopling of the high latitudes of the Siberian subcontinent.

scholarly journals Extension Staffing Models to Serve 4-H Clientele in Changing Times

2010 ◽  
Vol 5 (1) ◽  
pp. 105-111
Author(s):  
Donna R. Gillespie ◽  
Cindy A. Kinder
Keyword(s):  
County Level ◽  
Budget Cuts ◽  
The Past ◽  
South Central ◽  
Professional Network ◽  
Staffing Patterns ◽  
Changing Times ◽  
University Of Idaho ◽  
Central Idaho

In response to budget cuts in 2002, 4-H staffing models were restructured. The response by University of Idaho Extension was intended to continue meeting the needs of Idaho’s citizens with fewer UI Extension faculty. This staffing reorganization led to the formation of the District III 4-H Team who united to bring stronger 4-H programs to south central Idaho and expand programs to underserved audiences. Information from surveys and interviews over the past seven years reflects the effectiveness, challenges and successes of the District III 4-H Team. In Making the Best Better: 4-H Staffing Patterns and Trends in the Largest Professional Network in the Nation (2007), author Kirk A. Astroth notes a nationwide change in 4-H leadership at the county level from 4-H faculty to program assistants or coordinators. The information gathered in our research may help other states determine staffing models to meet the needs of clientele in these changing times.

A Past as a Place

2019 ◽  
pp. 271-301
Keyword(s):  
Case Studies ◽  
Central Andes ◽  
Fractal Model ◽  
Archaeological Research ◽  
The South ◽  
The Past ◽  
South Central ◽  
Specific Material ◽  
Ontological Framework

The existence of a situational concept indissolubly spatial and temporal in the Bolivian altiplano, better defined by the aymara term pacha, in the south-central Andes is well sustained by ethno-historic and ethnographic accounts. However, the implications of this concept for archaeological research have not been considered enough. Is especially suggestive that, the past being necessarily a place, humans may have conceived various ways to physically interact with their pasts through ceremonialism. This chapter considers the implication of this idea within a framework of archaeology of time, applying a fractal model of the pacha concept in its various nested scales. In order to illustrate the material forms that the idea of relating with the entities of a “place of the past” can adopt, this chapter discusses three case-studies along a historic sequence. The chapter finishes with some thoughts about the specific material conducts that can be adopted, even within the same ontological framework.

scholarly journals Can recovery from disturbance explain observed declines in total phosphorus in Precambrian Shield catchments?

2016 ◽  
Vol 73 (8) ◽  
pp. 1202-1212 ◽  
Author(s):  
Jill Crossman ◽  
M. Catherine Eimers ◽  
Shaun A. Watmough ◽  
Martyn N. Futter ◽  
Jason Kerr ◽  
...  
Keyword(s):  
Total Phosphorus ◽  
Soil Acidification ◽  
Model Performance ◽  
Timber Harvesting ◽  
Oligotrophic Lakes ◽  
The Past ◽  
Land Disturbance ◽  
South Central ◽  
And Performance ◽  
P Fluxes

The plausibility of land disturbance as a cause of declining phosphorus (P) concentrations in oligotrophic lakes within south-central Ontario, Canada, is evaluated using the process-based model INCA-P. The model was calibrated upon three catchments in the Muskoka–Haliburton region (MHR): Harp (HP), Dickie (DE), and Plastic (PC), which have varying degrees of declining P export and different forms of historic disturbances (timber harvesting, tree death, and soil acidification, respectively). Hindcasts (1978–2007) were run with and without simulated disturbances. Model performance of both DE and HP was greatly improved when effects of wetland tree deaths (DE) and harvesting (HP) were included. In PC, with no record of timber harvesting and relatively minor declines in P, initial hindcasts successfully accounted for the majority of interannual P fluxes, and performance was only marginally improved through the simulation of soil acidification. Vegetation decay, harvesting, and catchment acidification accounted for 63%, 24%, and 0.6%, respectively, of P export over the past 30 years. Of all disturbances, wetland vegetation death had the highest impact on areal P exports, indicating that riparian stability is particularly important.

Fossil legume fruits from tertiary strata of Puebla, Mexico

1994 ◽  
Vol 72 (7) ◽  
pp. 1027-1038 ◽  
Author(s):  
Susana Magallón-Puebla ◽  
Sergio R. S. Cevallos-Ferriz
Keyword(s):  
Plant Communities ◽  
Fossil Flora ◽  
Central Mexico ◽  
Arid Environments ◽  
The Past ◽  
South Central ◽  
Modern Species ◽  
Tropical America ◽  
Extinct Genus ◽  
The Town

A small assemblage of fossil legume fruits, leaf fragments, and leaflets has been recovered from the Tertiary (Oligocene) "Los Ahuehuetes" flora near the town of Tepexi de Rodríguez, Puebla, in south-central Mexico. Five legume fruits are described and compared with fruits of extant genera. Four fruit types were identified as belonging to the modern genera Prosopis (Mimoseae; Mimosoideae), Mimosa (Mimoseae; Mimosoideae), Lysiloma (Ingeae; Mimosoideae), and Sophora (Sophoreae; Papilionoideae). Another fruit exhibits a combination of characters unknown among extant legumes, and although superficially similar to some species of Papilionoideae, it represents an extinct genus. The four identified genera are diverse in the extant vegetation of Mexico; in fact, Mexico represents an important area of distribution for them. The presence of Prosopis, Mimosa, Lysiloma, and Sophora in the fossil flora of Puebla documents the occurrence of these genera in this part of their present area of distribution by the Oligocene. The climatic affinities of modern species of Mimosa, Lysiloma, and Sophora are so varied as to preclude any useful paleoclimatic inference. Prosopis is regularly associated with arid environments; however, the genus has been reported from fossil localities where humid conditions prevailed. This observation, together with the assemblage of plants that co-occur in the Los Ahuehuetes flora, suggests that plant communities of the past may have been composed, at least partly, of elements that today are associated with different habitats and environmental conditions. The fossil legume fruits from Los Ahuehuetes flora add to the previously known diversity of Leguminosae by the Tertiary, confirm tropical America as one of the important areas of radiation and diversification for Leguminosae, and contribute to the knowledge of Tertiary floras of southern North America. Key words: Leguminosae, Tertiary, Mexico, paleobotany, fossil legume.

Impact of wetland disturbance on phosphorus loadings to lakes

2014 ◽  
Vol 71 (11) ◽  
pp. 1695-1703 ◽  
Author(s):  
Kieran C. Pinder ◽  
M. Catherine Eimers ◽  
Shaun A. Watmough
Keyword(s):  
Tree Mortality ◽  
Field Surveys ◽  
The Past ◽  
South Central ◽  
Tree Community ◽  
Dead Trees ◽  
Standing Dead ◽  
Mixed Age ◽  
Wetland Cover

Total phosphorus (TP) concentrations have declined in many lakes and streams across south-central Ontario, Canada, over the past three decades, and changes have been most pronounced in wetland-dominated catchments. In this study, long-term (1980–2007) patterns in TP concentrations in streams were assessed at four wetland-dominated catchments that drain into Dickie Lake (DE) in south-central Ontario. Two of the subcatchments (DE5 and DE6) have particularly large wetland components (31%–34% of catchment area), and these wetlands are characterized by numerous standing dead trees and many young live trees (18–27 years old). These two streams exhibited large peaks in TP and potassium (K) export in the early 1980s. In contrast, TP and K export from DE8 and DE10 (wetland cover 19%–20%) were relatively flat over the entire record (1980–2007), and field surveys indicated negligible standing dead biomass in these wetlands and a relatively healthy, mixed-age tree community. The coincidence of high TP and K concentrations in the DE5 and DE6 streams as well as evidence of a disturbance event in their wetlands during the early 1980s suggest that disturbance events (e.g., flooding) that lead to wetland tree mortality may contribute to patterns in surface water TP observed in this region.

scholarly journals Neoglaciation in the Southern Kenai Mountains, Alaska

1990 ◽  
Vol 14 ◽  
pp. 319-322 ◽  
Author(s):  
Gregory C. Wiles ◽  
Parker E. Calkin
Keyword(s):  
Little Ice Age ◽  
Late Holocene ◽  
Ice Age ◽  
Past Century ◽  
Partial Control ◽  
The Past ◽  
Proglacial Lakes ◽  
Glacial Chronology ◽  
Historical Accounts ◽  
Ice Complex

A preliminary late-Holocene glacial chronology from the west flank of the southern Kenai Mountains, Alaska, is characterized by two major episodes of advance. Outlet glaciers of both the Harding Icefield and the Grewingk-Yalik ice complex were expanding across their present positions at 545 A.D. and again during the Little Ice Age, about 1500 A.D. The earliest of these Neoglacial advances is dated by radiocarbon ages from the outer rings of tree trunks rooted near the margins of Grewingk and Dinglestadt glaciers. Subsequently, ice margins retreated some distance behind their present positions allowing marked soil development before the last readvance through mature forest. Wood preserved in lateral moraines at Grewingk Glacier and from an uprooted stump at Tustemena Glacier date this later ice advance. Tree-ring ages, correlated with lichen diameters, suggest that this last advance was widespread and culminated in its Neoglacial maximum about 1800 A.D.. Since this time, glacier retreat has dominated in the area, punctuated by at least two pauses. Historical accounts and photographs document a mean rate of retreat of 27 m a−1 for the past century with partial control exerted by calving of ice margins into proglacial lakes.

From Naguatex to the River Daycao: The Route of the Hernando de Soto Expedition through Texas

1994 ◽  
Vol 14 (3) ◽  
pp. 199-225 ◽  
Author(s):  
James E. Bruseth ◽  
Nancy A. Kenmotsu
Keyword(s):  
Native American ◽  
The State ◽  
Late Prehistoric ◽  
East Central ◽  
The Past ◽  
South Central ◽  
Guadalupe River ◽  
Central Texas ◽  
Hernando De Soto ◽  
Late Prehistoric Period

Over the past several decades, many attempts have been made to trace the route of the Hernando de Soto expedition through Texas. All of these efforts have been based on an incomplete understanding of the archeological record relating to the 16th century in Texas. A number of archeological investigations have been conducted over the past several decades, and provide better knowledge of the late prehistoric period in Texas. This article examines the route of the de Soto expedition, under the command of Luis de Moscoso, through the state based on our present archeological knowledge. The expedition is proposed to have entered Texas along the Red River and traveled southward until reaching Caddoan settlements near Nacogdoches in the east-central portion of the state. From here the expedition traveled westward until reaching the Guadalupe River of south-central Texas, where the soldiers abandoned hopes of reaching New Spain by an overland route. Implications of the proposed route upon Native American populations of eastern Texas are discussed and related to the possible introduction of European diseases.

Psychosocial Health Issues in Pediatric Practices: Parents' Knowledge and Concerns

PEDIATRICS ◽  
1984 ◽  
Vol 74 (2) ◽  
pp. 183-190 ◽  
Author(s):  
Yolanda D. McCune ◽  
Miriam M. Richardson ◽  
Judith A. Powell
Keyword(s):  
Child Development ◽  
Psychosocial Health ◽  
Statistical Technique ◽  
Health Issues ◽  
Pediatric Practice ◽  
Behavioral Issues ◽  
The Past ◽  
South Central ◽  
Central United States ◽  
Child Development Knowledge

Parents' general knowledge of child development and the demographic factors associated with that knowledge were studied. A questionnaire was completed by 230 parents of patients from three quite different pediatric practices in the south-central United States. χ2 analysis was used as the major statistical technique. Results indicated that age, educational level, and income were associated with level of child development knowledge. Parents reported the sources and educational techniques that were most helpful to them in the past and present. The majority (81%) of the questions that parents wished to direct to pediatricians, given sufficient time, were concerned with psychosocial issues. It appears that the pediatric practice is a logical means of providing information to parents about their children's health concerns, both behavioral and physical. These results emphasize the importance of training pediatricians in behavioral issues and in improving their communication skills. The results are presented to help pediatricians select the anticipatory guidance and educational techniques that might be provided to parents through the pediatric practice.

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