Integration of biplanar X-ray, three-dimensional animation and particle simulation reveals details of human ‘track ontogeny’

The emergence of bipedalism had profound effects on human evolutionary history, but the evolution of locomotor patterns within the hominin clade remains poorly understood. Fossil tracks record in vivo behaviours of extinct hominins, and they offer great potential to reveal locomotor patterns at various times and places across the human fossil record. However, there is no consensus on how to interpret anatomical or biomechanical patterns from tracks due to limited knowledge of the complex foot–substrate interactions through which they are produced. Here, we implement engineering-based methods to understand human track formation with the ultimate goal of unlocking invaluable information on hominin locomotion from fossil tracks. We first developed biplanar X-ray and three-dimensional animation techniques that permit visualization of subsurface foot motion as tracks are produced, and that allow for direct comparisons of foot kinematics to final track morphology. We then applied the discrete element method to accurately simulate the process of human track formation, allowing for direct study of human track ontogeny. This window lets us observe how specific anatomical and/or kinematic variables shape human track morphology, and it offers a new avenue for robust hypothesis testing in order to infer patterns of foot anatomy and motion from fossil hominin tracks.

Crown outline analysis of the hominin upper third molar from the Megalopolis Basin, Peloponnese, Greece

The left upper third molar from the Megalopolis Basin is enigmatic due to its problematic preservation and context. The Megalopolis molar is the only possible human fossil known to date from the Megalopolis Basin. It was found on the surface during geological surveys in 1962-63. Based on the faunal assemblage collected during the same survey, it was proposed to be of Middle Pleistocene age and possibly one of the oldest human fossils in Europe. However, its actual geological age is unknown. In the past, dental crown outline analysis has been successfully used to differentiate between hominin species and populations. We applied the method to upper third molars, attempting to shed light on the affinities of the Megalopolis specimen. Principal component analysis (PCA) of the crown outline shape grouped the Megalopolis molar with our Homo sapiens sample; however, the PCA in form space, including shape plus size, as well as Procrustes distances based on overall shape, grouped it with our Neanderthal comparative sample. We conclude that its most likely identification is as a member of the Neanderthal lineage. However, we urge further analyses with an increased fossil comparative sample to include representatives of Homo heidelbergensis, which is underrepresented in our study. The Megalopolis molar contributes to the scarce Pleistocene human fossil record of Greece and highlights the potential of the Megalopolis Basin for yielding further paleoanthropological finds.

Cancer Cell Growth: - A Mini-Review Part-4: First threat (atherosclerotic lesions)

The first 3 issues about cancer cells have been tried to explain -in the author papers- how the cells grow by using more energy in the tissue or organ compared to other cells, with the justification of scientific sources. The 4th series of articles will include detailed determinations about the initial threat of a cell growing in an organ or tissue to the organ or tissue by multiplying more than other cells. When a cell proliferates to a sufficient number of cells as mentioned in previous chapters, it begins to make its first threat. It fulfills this cell threat by expressing more than 100 disease forms within the organ. This is a phenomenon that occurs in all living cells. This was even seen in the most primitive invertebrates such as Mollusca and Arthropoda. Examinations of dinosaurs living 100 million years ago revealed the presence of neoplasms. Traces of the above constriction have been found in the cell work done on a 100,000-year-old human fossil. The most important sign of the first threat is phenotypic and genetic change. It creates the impression that it is threatened by a bacterial colony relative to other cells. These cells MIMIC the survival behavior and resistance of unicellular organisms that lived in the same ancient times.

Bacteria, guano and soot: Source assessment of organic matter preserved in black laminae in stalagmites from caves of the Sierra de Atapuerca (N Spain)

Speleothems are a recognized source of paleoclimatic information, but their value as a source of signals from human activities in caves with an archaeological record has rarely been explored. Previous studies of speleothems in the Sierra de Atapuerca karst system (Burgos, northern Spain) revealed an important human fossil record, provided information about human activities in and around these caves, and the impacts on their natural environment. The present study reports the results of molecular characterization of dark-colored laminae from the stalagmites Ilargi (Galería de las Estatuas) and GS1, GS2, and GS3 (Galería del Silo), by pyrolysis-GC-MS (Py-GC-MS) and thermally assisted hydrolysis and methylation (THM-GC-MS). The features of the organic matter demonstrate the presence of (1) a dominant aliphatic fraction probably from in situ bacterial and ex situ plant-derived lipids, (2) black carbon (from soot and/or charcoal), (3) polysaccharides and N-rich moieties (probably from bat guano and microbial sources), and (4) a signal of terpenoid derivatives that may originate from the overlying limestone (kerogen) and extant gymnosperm resin (soils) or cyanobacteria (cave). Some plant-derived lignin may be present as well but was not identified unambiguously. It is concluded that this approach allows identifying multiple general sources of organic matter which can help understand speleothem formation processes, and evidence of soot deposition could be clearly linked to human activities.

A method for resolving changes in atmospheric He ∕ N₂ as an indicator of fossil fuel extraction and stratospheric circulation

The atmospheric He/N2 ratio is expected to increase due to the emission of He associated with fossil fuels and is expected to also vary in both space and time due to gravitational separation in the stratosphere. These signals may be useful indicators of fossil fuel exploitation and variability in stratospheric circulation, but direct measurements of He/N2 ratio are lacking on all timescales. Here we present a high-precision custom inlet system for mass spectrometers that continuously stabilizes the flow of gas during sample–standard comparison and removes all non-noble gases from the gas stream. This enables unprecedented accuracy in measurement of relative changes in the helium mole fraction, which can be directly related to the 4He/N2 ratio using supplementary measurements of O2/N2, Ar/N2 and CO2. Repeat measurements of the same combination of high-pressure tanks using our inlet system achieves a He/N2 reproducibility of ∼ 10 per meg (i.e., 0.001 %) in 6–8 h analyses. This compares to interannual changes of gravitational enrichment at ∼ 35 km in the midlatitude stratosphere of order 300–400 per meg and an annual tropospheric increase from human fossil fuel activity of less than ∼ 30 per meg yr−1 (bounded by previous work on helium isotopes). The gettering and flow-stabilizing inlet may also be used for the analysis of other noble-gas isotopes and could resolve previously unobserved seasonal cycles in Kr/N2 and Xe/N2.

Measurements of atmospheric He/N₂ as an indicator of fossil fuel extraction and stratospheric circulation

The atmospheric He/N2 ratio is expected to be increasing due to the emission of He associated with fossil fuels and is expected to also vary in both space and time due to gravitational separation in the stratosphere. These signals may be useful indicators of fossil-fuel exploitation and variability in stratospheric circulation, but direct measurements of He/N2 ratio are lacking on all time scales. Here we present a high-precision custom inlet system for mass spectrometers that continuously stabilizes the flow of gas during sample-standard comparison and removes all non-noble gases from the gas stream, enabling unprecedented accuracy in measurement of relative changes in the 4He/N2 ratio. Repeat measurements of the same combination of high-pressure tanks using our inlet system achieves a reproducibility of ~ 10 per meg (i.e. 0.001 %) in 6–8 h analyses. This compares to interannual changes of He/N2 gravitational enrichment at ~ 35 km in the mid latitude stratosphere of order 300–400 per meg, and an annual tropospheric increase from human fossil fuel activity of less than ~ 30 per meg y−1 (bounded by previous work on helium isotopes). The gettering and flow-stabilizing inlet may also be used for the analysis of other noble gas isotopes and could resolve previously unobserved seasonal cycles in Kr/N2 and Xe/N2.