All-Electron Path Integral Monte Carlo Simulations of Warm Dense Matter: Application to Water and Carbon Plasmas

We develop an all-electron path integral Monte Carlo (PIMC) method with free-particle nodes for warm dense matter and apply it to water and carbon plasmas. We thereby extend PIMC studies beyond hydrogen and helium to elements with core electrons. PIMC pressures, internal energies, and pair-correlation functions compare well with density functional theory molecular dynamics (DFT-MD) at temperatures of (2.5-7.5)$\times10^5$ K and both methods together form a coherent equation of state (EOS) over a density-temperature range of 3--12 g/cm$^3$ and 10$^4$--10$^9$ K

Water-quality Effects on Phytoplankton Species and Density and Trophic State Indices at Big Base and Little Base Lakes, Little Rock Air Force Base, Arkansas, June through August, 2015

Big Base and Little Base Lakes are located on Little Rock Air Force Base, Arkansas, and their close proximity to a dense residential population and an active military/aircraft installation make the lakes vulnerable to water-quality degradation. The U.S. Geological Survey (USGS) conducted a study from June through August 2015 to investigate the effects of water quality on phytoplankton species and density and trophic state in Big Base and Little Base Lakes, with particular regard to nutrient concentrations. Nutrient concentrations, trophic-state indices, and the large part of the phytoplankton biovolume composed of cyanobacteria, indicate eutrophic conditions were prevalent for Big Base and Little Base Lakes, particularly in August 2015. Cyanobacteria densities and biovolumes measured in this study likely pose a low to moderate risk of adverse algal toxicity, and the high proportion of filamentous cyanobacteria in the lakes, in relation to other algal groups, is important from a fisheries standpoint because these algae are a poor food source for many aquatic taxa. In both lakes, total nitrogen to total phosphorus (N:P) ratios declined over the sampling period as total phosphorus concentrations increased relative to nitrogen concentrations. The N:P ratios in the August samples (20:1 and 15:1 in Big Base and Little Base Lakes, respectively) and other indications of eutrophic conditions are of concern and suggest that exposure of the two lakes to additional nutrients could cause unfavorable dissolved-oxygen conditions and increase the risk of cyanobacteria blooms and associated cyanotoxin issues

Modulation of integrin-linked kinase (ILK) expression in human oesophageal squamous cell carcinoma cell lines by the EGF and TGFβ1 growth factors

BACKGROUND: Integrin-linked kinase (ILK) is a ubiquitously expressed protein kinase that has emerged as one of the points of convergence between integrin- and growth factor-signalling pathways. RESULTS: In this study we identify the ILK isoform expressed in five human oesophageal squamous cell carcinoma cell lines of South African origin as ILK1, and demonstrate its cellular distribution. ILK expression, although similar in the majority of the cell lines, did show variation. Furthermore, the ILK expressed was shown to be catalytically functional. The effect of growth factors on ILK expression was examined. An increase in ILK expression, following EGF and TGFβ1 exposure, was a trend across all the five oesophageal carcinoma cell lines tested. CONCLUSION: These results suggest that growth factor modulation of ILK expression relies on the internalisation/recycling of growth factor receptors and stimulation of the PI3K pathway, which may have implications with regards to cell adhesion and tumourigenesis

Rise and Fall of the Beringian Steppe Bison

The widespread extinctions of large mammals at the end of the Pleistocene epoch have often been attributed to the depredations of humans; here we present genetic evidence that questions this assumption. We used ancient DNA and Bayesian techniques to reconstruct a detailed genetic history of bison throughout the late Pleistocene and Holocene epochs. Our analyses depict a large diverse population living throughout Beringia until around 37,000 years before the present, when the population’s genetic diversity began to decline dramatically. The timing of this decline correlates with environmental changes associated with the onset of the last glacial cycle, whereas archaeological evidence does not support the presence of large populations of humans in Eastern Beringia until more than 15,000 years later.   Article Summary by Jonathan C. Driver, May 2015   This article explores the movement of North American bison and the special significance of Tse’K’wa in this research, shedding insight into how the first Paleoindian peoples of Canada arrived at the land. One of the fascinating aspects about archaeology today is the speed with which new scientific techniques are developed and applied to archaeological materials. This paper demonstrates why it is so important to keep material safely stored after it has been excavated – because you never know when it will be valuable to a future researcher or when it can yield new information about the past.   Quite a few years after the excavations at Tse’K’wa were finished I was approached by Alan Cooper and Beth Shapiro of Oxford University about the possibility of sampling early bison bones from the site, to see if they still had DNA preserved. Beth was writing her doctoral thesis on the evolution of bison, and she was being supervised by Alan, a highly accomplished researcher into ancient DNA. It turned out that the Tse’K’wa bison were well preserved, and Beth was able to extract DNA and include it in the study of hundreds of samples from North America and Asia. As an added bonus, Beth and Alan arranged for radiocarbon dates to be run on every bone they studied.This added to our understanding of the age of the site\u27s earliest material.   Beth summarized her doctoral research in this paper, published in the very prestigious journal “Science”. The many contributors to her research were listed as co-authors, recognizing that each of us had contributed in a small way to the research, by sharing samples and ideas.  While the paper mainly deals with Beth’s conclusions about the evolutionary history of bison, for those interested in Tse’K’wa and the history of the early peoples of Canada, there was a fascinating tidbit of information contained in the Tse’K’wa bison DNA – they were from two quite distinct populations.   To understand the significance of this, we must first consider the impact of the extensive ice sheets that formed across Canada about 20,000 years ago. The ice sheets separated North American bison into two populations. One group of bison herds lived to the south of the ice sheets, in what is today, the continental USA and very southern parts of Saskatchewan, Alberta and B.C. The other population lived in unglaciated regions of, what is today, Yukon, Alaska and northeast Asia. These two populations can be distinguished by minor differences in their DNA. When Beth studied the bison fossils from across the vast region of their ice-age distribution she found that in every location except one the bison were either northern or southern types. The one exception was Tse’K’wa where bison from both the north and south were found.   The explanation for this seems fairly straightforward. When the western Canadian ice sheets melted and new pastures were developed, northern bison began to move south through the Yukon and into northern and central BC and Alberta. At the same time, the southern bison began to move north, also following pastures that developed on the recently de-glaciated  landcapes.  Finally, the northern and southern populations met in the Peace River region. There is no evidence that they bred with each other, and, based on the genetics of modern bison in North America it appears that the southern form survived and evolved into the bison we are familiar with today.   The Tse’K’wa data suggest the meeting of bison populations must have occurred around the same time the site was first occupied by humans, as it is very unlikely that two genetically distinct populations of bison could have lived in the same environment without interbreeding or one of them becoming extinct. This means the establishment of a viable migration route for animals (and people) from Alaska through Yukon, B.C., Alberta and into continental USA must have happened after the dates of the earliest human presence in the continental USA and South America. Therefore, the first people to enter North America could not have migrated through an ice-free corridor along the eastern slopes of the Rockies. Assuming they entered the Americas during the last ice age, then the most likely route would be down the coast of Alaska and British Columbia. Interestingly, this hypothesis was proposed by the director of the 1983 Tse’K’wa excavations, Knut Fladmark, in a paper published in 1979!   The Tse’K’wa stone artifacts lend support to this scenario. The earliest spear point at the site – the “fluted point” – is stylistically very similar to artifacts found in the south, which date a little earlier than those at Tse’K’wa. This supports the notion that the earliest inhabitants of the site were part of a human population that began to move north (perhaps out of southern Alberta and northern Montana)  following the bison herds as they moved north to exploit the newly created grassland environments that formed as ice melted and glacial lakes drained away

The Opportunity Spectrum -- Concept and Behavioral Information in Outdoor Recreation Resource Supply Inventories: Background and Application

The paper describes an outdoor recreation resource (ORR) Supply Inventory and Classification (SIC) System that is being developed for multiple use natural resource planning. Four previously developed ORR SIC’s on which this system was built are described briefly. A general model for natural resource planning is presented to show how the proposed ORR SIC fits into a larger planning framework. The proposed SIC System is described and its application for regional and unit planning is explained. Relationships between OR consumers\u27 preferences for specific types of satisfying experiences and their preferences for specific attributes of the physical, social, and managerial settings are translated into specific and objective criteria proposed for inventorying and classifying lands as to their potential for providing particular types of OR opportunities on the spectrum