scholarly journals New Record of Terminal Pleistocene Elk/Wapiti (Cervus canadensis) from Ohio, USA

2021 ◽  
Vol 121 (2) ◽  
pp. 2-14
Author(s):  
Brian G. Redmond ◽  
David L. Dyer ◽  
Charles Stephens
Keyword(s):  
Deciduous Forest ◽  
Bone Collagen ◽  
Large Size ◽  
Peat Deposits ◽  
Temporal Placement ◽  
Cervus Canadensis ◽  
Terminal Pleistocene ◽  
The Individual ◽  
Late Paleoindian ◽  
Mammut Americanum

The earliest appearance of elk/wapiti (Cervus canadensis) in eastern North America is not thoroughly documented due to the small number of directly dated remains. Until recently, no absolute dates on elk bone older than 10,000 14C yr BP (11,621 to 11,306 calibrated years (cal yr) BP) were known from this region. The partial skeleton of the Tope Elk was discovered in 2017 during commercial excavation of peat deposits from a small bog in southeastern Medina County, Ohio, United States. Subsequent examination of the remains revealed the individual to be a robust male approximately 8.5 years old at death. The large size of this individual is compared with late Holocene specimens and suggests diminution of elk since the late Pleistocene. Two accelerator mass spectrometry (AMS) radiocarbon assays on bone collagen samples taken from the scapula and metacarpal of this individual returned ages of 10,270 ± 30 14C yr BP (Beta-477478) (12,154 to 11,835 cal yr BP) and 10,260 ± 30 14C yr BP (Beta-521748) (12,144 to 11,830 cal yr BP), respectively. These results place Cervus canadensis in the terminal Pleistocene of the eastern woodlands and near the establishment of the mixed deciduous forest biome over much of the region. This early temporal placement also situates this early elk as closely following the last representatives of now-extinct megafauna such as the American mastodon (Mammut americanum) and contemporary with the Late Paleoindian inhabitants of the region.

The sensitivity of Neotoma to climate change and biodiversity loss over the late Quaternary

2021 ◽  
pp. 1-15
Author(s):  
Catalina P. Tomé ◽  
S. Kathleen Lyons ◽  
Seth D. Newsome ◽  
Felisa A. Smith
Keyword(s):  
Body Size ◽  
Late Quaternary ◽  
Climatic Variability ◽  
Isotope Analysis ◽  
Biodiversity Loss ◽  
Bone Collagen ◽  
Cam Plants ◽  
The Holocene ◽  
Carbon And Nitrogen ◽  
Terminal Pleistocene

Abstract The late Quaternary in North America was marked by highly variable climate and considerable biodiversity loss including a megafaunal extinction event at the terminal Pleistocene. Here, we focus on changes in body size and diet in Neotoma (woodrats) in response to these ecological perturbations using the fossil record from the Edwards Plateau (Texas) across the past 20,000 years. Body mass was estimated using measurements of fossil teeth and diet was quantified using stable isotope analysis of carbon and nitrogen from fossil bone collagen. Prior to ca. 7000 cal yr BP, maximum mass was positively correlated to precipitation and negatively correlated to temperature. Independently, mass was negatively correlated to community composition, becoming more similar to modern over time. Neotoma diet in the Pleistocene was primarily sourced from C3 plants, but became progressively more reliant on C4 (and potentially CAM) plants through the Holocene. Decreasing population mass and higher C4/CAM consumption was associated with a transition from a mesic to xeric landscape. Our results suggest that Neotoma responded to climatic variability during the terminal Pleistocene through changes in body size, while changes in resource availability during the Holocene likely led to shifts in the relative abundance of different Neotoma species in the community.

scholarly journals Crown Structure Explains the Discrepancy in Leaf Phenology Metrics Derived from Ground- and UAV-Based Observations in a Japanese Cool Temperate Deciduous Forest

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 425
Author(s):  
Noviana Budianti ◽  
Hiromi Mizunaga ◽  
Atsuhiro Iio
Keyword(s):  
Deciduous Forest ◽  
Leaf Expansion ◽  
Image Resolution ◽  
Leaf Phenology ◽  
Visual Interpretation ◽  
Temperate Deciduous Forest ◽  
Individual Tree ◽  
Crown Structure ◽  
Uav Images ◽  
The Individual

Unmanned aerial vehicles (UAV) provide a new platform for monitoring crown-level leaf phenology due to the ability to cover a vast area while offering branch-level image resolution. However, below-crown vegetation, e.g., understory vegetation, subcanopy trees, and the branches of neighboring trees, along with the multi-layered structure of the target crown may significantly reduce the accuracy of UAV-based estimates of crown leaf phenology. To test this hypothesis, we compared UAV-derived crown leaf phenology results against those based on ground observations at the individual tree scale for 19 deciduous broad-leaved species (55 individuals in total) characterized by different crown structures. The mean crown-level green chromatic coordinate derived from UAV images poorly explained inter- and intra-species variations in spring leaf phenology, most probably due to the consistently early leaf emergence in the below-crown vegetation. The start dates for leaf expansion and end dates for leaf falling could be estimated with an accuracy of <1-week when the influence of below-crown vegetation was removed from the UAV images through visual interpretation. However, a large discrepancy between the phenological metrics derived from UAV images and ground observations was still found for the end date of leaf expansion (EOE) and start date of leaf falling (SOF). Bayesian modeling revealed that the discrepancy for EOE increased as crown length and volume increased. The crown structure was not found to contribute to the discrepancy in SOF value. Our study provides evidence that crown structure is a pivotal factor to consider when using UAV photography to reliably estimate crown leaf phenology at the individual tree-scale.

Radiocarbon Dating and Dietary Stable Isotope Analysis of Kwaday Dän Ts'inchí

2007 ◽  
Vol 72 (4) ◽  
pp. 719-734 ◽  
Author(s):  
Michael P. Richards ◽  
Sheila Greer ◽  
Lorna T. Corr ◽  
Owen Beattie ◽  
Alexander Mackie ◽  
...  
Keyword(s):  
Radiocarbon Dating ◽  
Isotope Analysis ◽  
Human Remains ◽  
Isotopic Analysis ◽  
High Elevation ◽  
Bone Collagen ◽  
Contact Period ◽  
European Contact ◽  
Ams Dating ◽  
The Individual

We report here on the results of AMS dating and isotopic analysis of the frozen human remains named Kwaday Dän Ts'inchí and associated materials recovered from a glacier located in Northwest British Columbia, Canada in 1999. The isotopic analysis of bone collagen (bulk and single amino acids) from the individual indicates a strongly marine diet, which was unexpected given the location of this find, more than 100 km inland eroding out of a high elevation glacier; however, bulk hair and bone cholesterol isotopic values indicate a shift in diet to include more terrestrial foods in the year before death. The radiocarbon dating is not straightforward, as there are difficulties in determining the appropriate marine correction for the human remains, and the spread of dates on the associated artifacts clearly indicates that this was not a single use site. By combining the most recent date on a robe worn by Kwaday Dän Ts'inchi with direct bone collagen dates we conclude that the individual likely dates to between cal A.D. 1670 to 1850, which is in the pre-(or early) European contact period for this region.

Taxonomic application of macro and micro morphological characters of seeds in Astragalus L. (Galegeae, Fabaceae) in India

Phytotaxa ◽  
2021 ◽  
Vol 502 (2) ◽  
pp. 191-207
Author(s):  
SHIVANI KASHYAP ◽  
CHANDAN KUMAR SAHU ◽  
ROHIT KUMAR VERMA ◽  
LAL BABU CHAUDHARY
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Light Microscopy ◽  
Seed Coat ◽  
Morphological Plasticity ◽  
Morphological Characters ◽  
Individual Species ◽  
Large Size ◽  
The Individual ◽  
Scanning Electron

Due to large size and enormous morphological plasticity, the taxonomy of the genus Astragalus is very complex and challenging. The identification and grouping of species chiefly based on macromorphological characters become sometimes difficult in the genus. In the present study, the micromorphology of the seeds of 30 species belonging to 14 sections of Astragalus from India has been examined applying scanning electron microscopy (SEM) along with light microscopy (LM) to evaluate their role in identification and classification. Attention was paid to colour, shape, size and surface of seeds. The overall size of the seeds ranges from 1.5–3.2 × 0.8–2.2 mm. The shape of the seeds is cordiform, deltoid, mitiform, orbicular, ovoid and reniform. The colour of seeds varies from brown to blackish-brown to black. Papillose, reticulate, ribbed, rugulate and stellate patterns were observed on the seed coat surface (spermoderm) among different species. The study reveals that the seed coat ornamentations have evolved differently among species and do not support the subgeneric and sectional divisions of the genus. However, they add an additional feature to the individual species, which may help in identification in combination with other macro-morphological features.

Taxonomic overview and tusk growth analyses of Ziegler Reservoir proboscideans

2014 ◽  
Vol 82 (3) ◽  
pp. 518-532 ◽  
Author(s):  
Daniel C. Fisher ◽  
Michael D. Cherney ◽  
Cody Newton ◽  
Adam N. Rountrey ◽  
Zachary T. Calamari ◽  
...  
Keyword(s):  
High Elevation ◽  
Environmental Pressures ◽  
Terminal Pleistocene ◽  
Fossil Site ◽  
Males And Females ◽  
Low Levels ◽  
Colorado Rockies ◽  
Mammut Americanum ◽  
Source Of Information ◽  
Mis 5

AbstractAt an altitude of 2705 m in the Colorado Rockies (USA), the Ziegler Reservoir fossil site gives a rare look at a high-elevation ecosystem from the late Pleistocene (especially MIS 5) of North America. Remains of more than four mammoths and about 35 mastodons dominate the macrofossil assemblage. Mammoth remains are attributed to Mammuthus columbi, and mastodon remains are referred to the well-known, continent-wide Mammut americanum. Mastodon remains occur within and between several lake-margin slump deposits. Their deposition must therefore have occurred as events that were to some degree separate in time. We treat the mastodon assemblage in each stratigraphic unit as a source of information on environmental conditions during the lives of these individuals. Mastodon mandibular tusks are abundant at the site and represent both males and females, from calves to full-grown adults. This study presents the first attempt to use microCT, thin-section, and isotope records from mandibular tusks to reconstruct features of life-history. We recognize an up-section trend in δ18O profiles toward higher values, suggestive of warmer temperatures. Throughout this sequence, mastodon growth histories show low mean sensitivities suggestive of low levels of environmental stress. This work helps frame expectations for assessing environmental pressures on terminal Pleistocene populations.

A Sampling Approach to Modeling and Control of a Large-Size Robot Population

2010 ◽  
Author(s):  
Dejan Milutinovic´ ◽  
Devendra P. Garg
Keyword(s):  
Stochastic Process ◽  
Optimal Control ◽  
Close Relation ◽  
Modeling And Control ◽  
Stochastic Sampling ◽  
Large Size ◽  
Continuous Components ◽  
Estimation And Control ◽  
The Individual ◽  
And Control

Motivated by the close relation between estimation and control problems, we explore the possibility to utilize stochastic sampling for computing the optimal control for a large-size robot population. We assume that the individual robot state is composed of discrete and continuous components, while the population is controlled in a probability space. Utilizing a stochastic process, we can compute the state probability density function evolution, as well as use the stochastic process samples to evaluate the Hamiltonian defining the optimal control. The proposed method is illustrated by an example of centralized optimal control for a large-size robot population.

Partial structural analysis of concanavalin A binding glycopeptides of large size from human teratocarcinoma-derived cells: cleavage by hydrazinolysis and alkaline borohydride

1982 ◽  
Vol 60 (7) ◽  
pp. 749-756 ◽  
Author(s):  
Maija-Liisa Rasilo ◽  
Ossi Renkonen
Keyword(s):  
Structural Analysis ◽  
Concanavalin A ◽  
Relative Mass ◽  
Human Origin ◽  
Con A ◽  
Large Size ◽  
Teratocarcinoma Cells ◽  
The Individual ◽  
Mouse Teratocarcinoma

Pronase digests of cultured teratocarcinoma-derived cells (PA 1) of human origin have been previously shown to contain large-sized glycopeptides (relative mass (Mr) > 7400), of which 15–23% are retained by columns of concanavalin A (Con A) – Sepharose and can be eluted with 10 mM methyl α-D-mannopyranoside. The present data show that this fraction (A – Con A II) contains a family of glycopeptides that are degradable with anhydrous hydrazine as well as with 0.05 M NaOH – 1 M NaBH4. The cleavage products representing individual oligosaccharide chains, presumably as oligosaccharides and glycopeptides, consisted mostly of medium- (Mr 1400–6000) and small-sized (Mr < 1400) molecules. This implies that glycopeptides bearing several oligosaccharide chains were present in A – Con A II. Most of the individual oligosaccharide chains were not bound to Con A – Sepharose, but some were retained by the lectin column in the same way as the original glycopeptides. Some of the oligosaccharides were degraded partially with endo-β-galactosidase from Escherichia freundii suggesting the presence of GalβGlcNAcβ repeats. The present findings show that A – Con A II may be different from the "embryonic" glycopeptides of mouse teratocarcinoma cells that are reportedly not cleaved by mild alkaline borohydride treatment. Instead, A – Con A II is reminiscent of the T-1 glycopeptide of glycophorin.

Aspects of the Organization of Central Nervous Pathways in Aplysia Depilans

1962 ◽  
Vol 39 (1) ◽  
pp. 45-69
Author(s):  
G. M. HUGHES ◽  
L. TAUC
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Ganglion Cells ◽  
Rhythmic Activity ◽  
Large Size ◽  
The Central Nervous System ◽  
The Individual ◽  
Two Sides ◽  
Pleural Ganglion

1. The organization of the central nervous system of Aplysia depilans has been investigated in whole animal and isolated ganglion preparations using mechanical and electrical stimulation. 2. Intracellular micro-electrodes have been used to record activity in nerve cells of the abdominal ganglia in situ. Some cells are spontaneously active and quite unaffected by mechanical stimulation, whereas others show varying degrees of responsiveness. Those which are unaffected may exhibit regular rhythmic activity or intermittent bursts which are intrinsic to the cells themselves but in other cases are due to synaptic input from other central neurones. 3. In isolated central nervous system preparations a special study of the pleural ganglion has revealed many types of cell with electrical activity similar to that shown in isolated abdominal ganglion preparations. A notable feature of the pleural ganglion cells was the large size of the excitatory post-synaptic potentials recorded in response to stimulation of pre-synaptic fibres. 4. Different types of branching of cells of the pleural ganglia were investigated. By observing the somatic potential it was possible to decide in which nerve a particular cell sent collateral branches and which nerves contained fibres affecting the cell synaptically. By this means it was clear that a large number of pathways connect the cerebral and pleural ganglia on each side. 5. A large number of direct pathways were found of nerve fibres passing through ganglia without any synapse. 6. Synaptic pathways varied in the number and intrinsic properties of the individual synapses along their route. Synapses between fibres in the nerves innervating the foot and parapodial lobes of the two sides were not as common as has been described for Ariolimax. 7. In general the results have shown a great variety in the extent to which afferent stimulation may affect the whole or part of the central nervous system. They have also revealed the great multiplicity in the pathways whereby this is achieved.

Superelement-Based Modeling of Load Distribution in Large-Size Slewing Bearings

2006 ◽  
Vol 129 (4) ◽  
pp. 459-463 ◽  
Author(s):  
Tadeusz Smolnicki ◽  
Eugeniusz Rusiński
Keyword(s):  
Numerical Models ◽  
Original Method ◽  
Large Size ◽  
Track System ◽  
Load Carrying ◽  
Rolling Element ◽  
Rolling Elements ◽  
The Individual ◽  
Slewing Bearings ◽  
Supporting Structures

The supporting structures in large-size slewing bearings are highly flexible. In order to choose the proper bearing and shape the load-carrying structure one must estimate the distribution of forces among the individual rolling elements. Advanced numerical models are needed for this. An original method of modeling the rolling element-track system is presented and its usefulness for modeling large-size bearings is demonstrated. The results of an exemplary analysis are presented in the form of graphs and figures. The superelement-based discrete bearing models are so far most comprehensive and take into account all the phenomena involved in the bearing-supporting structures system. The application of the finite-element method and the models based on the track-rolling element-track superelement made it possible to determine the effect of the deformability of the supporting structures and the nonuniformity of their flexibility on the loading of the rolling elements in the two-row bearing. The use of formulas which do not take into account the flexibility of the supporting structures to determine the distribution of the load among the rolling elements is unacceptable.

scholarly journals Comparison of Radiocarbon Ages from Different Organic Fractions in Tropical Peat Cores: Insights from Kalimantan, Indonesia

Radiocarbon ◽  
2008 ◽  
Vol 50 (3) ◽  
pp. 359-372 ◽  
Author(s):  
Raphael A J Wüst ◽  
Geraldine E Jacobsen ◽  
Haitse von der Gaast ◽  
Andrew M Smith
Keyword(s):  
Bulk Sample ◽  
Pollen Extract ◽  
Age Difference ◽  
Tropical Peat ◽  
Peat Deposits ◽  
Extract Fraction ◽  
Organic Fractions ◽  
The Individual ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Various organic fractions of an Indonesian tropical peat deposit were dated using radiocarbon accelerator mass spectrometry (AMS). Four different depth layers, deposited during the last 28,000 14C yr, were analyzed and the data compared to bulk sample analyses. The pollen extracts consistently produced the oldest dates. The bulk samples (<250 μm and <100 μm) often yielded the youngest dates. The age difference between the individual fractions depended on the layer depth and hence the true age of the sampled peats. The age discrepancy was highest (∼16,000 14C yr) in the oldest peat material. We interpret this to be a consequence of the input of organic matter over a long period of time, with peat oxidation and/or no peat accumulation during the last glacial maximum (LGM). The age discrepancies were smaller (between 10 and 900 14C yr) for the Holocene peat samples. It was concluded that the pollen extract fraction might be the most reliable fraction for dating tropical peat deposits that are covered by deeply rooting vegetation.

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