Energy, Technology, and Culture: The Paris Agreement, Social Conflict, and Cultural Evolution

In this essay, I will explore anthropologist Leslie White’s concept of cultural evolution and its relation to energy, technology, and social forces and conflicts

The Value of the Dead: The Commodification of Corpses in Western Culture

Since the 19th century, the deceased human body and its parts have been increasingly dehumanized, objectified, and commodified in Western culture. Thus, in a relatively short period of time, the corpse became, and continues to be, a highly valuable source of both economic and cultural capital for scientific and medical researchers, numerous industries, and much of society

Computational Fluid Dynamics Modeling of the Effects of Water Injection in a Diesel Engine

Water injection has been used in internal combustion engines for many years. It has been used to cool combustion temperatures, reduce emissions, and in some instances clean carbon buildup from the cylinder. Research has shown that the water to fuel mass ratio is most effective between 20-30%, so the upper and lower limit were used for simulations in Converge CFD. To validate the CFD model, a case without water injection was compared to experimental data from Sandia National Laboratory. The predicted in-cylinder pressure and heat release rate showed good agreement with the experimental data. Cases were run with the injection of the water at 65 and 95 degrees BTDC to increase vaporization and reduce wall film. The water droplet size injected was the principal focus of the study as its effects on emissions had not been investigated. The water droplet sizes used were 0.196, 0.210, 0.240, 0.286 μm. The 0.196 μm droplet was chosen because it was equivalent to the fuel droplet diameter. The others were from literature research for tests done on the effect injected water droplet sizes had on the flame length and speed. It was found that the highest reduction in temperature and pressure was observed with the water injected closer to TDC; however, this commonly resulted in larger emissions reductions. Also, increasing the water mass ratio generally reduced the temperature, pressure, and heat release rate more, which often further reduced the emissions. Maximum NOx reductions of 5.61% using the 0.210 μm droplet size with 20% water and 7.66% using the 0.240 μm droplet size with 30% water were observed. Droplet size comparison showed up to a 9.67% variation in the NOx formation. Simulations were then run by changing the temperature of the water being injected ±20K from the original temperature of 368K. The decreased water temperature cases showed a larger variation between the results for the NOx formation in water injected at 65 and 95 degrees BTDC. Water was then injected at TDC which showed a 48.3% reduction of NOx. However, all other emissions and combustion properties were negatively affected with the TDC injection timing

Slow carbon and nutrient accumulation in trees established following fire exclusion in the southwestern United States.

Increasing tree density that followed fire exclusion after the 1880s in the southwestern United States may have also altered nutrient cycles and led to a carbon (C) sink that constitutes a significant component of the U.S. C budget. Yet, empirical data quantifying century-scale changes in C or nutrients due to fire exclusion are rare. We used tree-ring reconstructions of stand structure from five ponderosa pine-dominated sites from across northern Arizona to compare live tree C, nitrogen (N), and phosphorus (P) storage between the 1880s and 1990s. Live tree biomass in the 1990s contained up to three times more C, N, and P than in 1880s. However, the increase in C storage was smaller than values used in recent U.S. C budgets. Furthermore, trees that had established prior to the 1880s accounted for a large fraction (28-66%) of the C, N, and P stored in contemporary stands. Overall, our century-scale analysis revealed that forests of the 1880s were on a trajectory to accumulate C and nutrients in trees even in the absence of fire exclusion, either because growing conditions became more favorable after the 1880s or because forests in the 1880s included age or size cohorts poised for accelerated growth. These results may lead to a reduction in the C sink attributed to fire exclusion, and they refine our understanding of reference conditions for restoration management of fire-prone forests

Generalization of Word Retrieval Following Semantic Feature Treatment

The purpose of this research was to analyze generalization effects following semantic feature treatment (SFT) for aphasia. The effectiveness of SFT at improving accuracy and speed of word retrieval, generalization to untreated words and discourse tasks and the influence of shared features was examined. The three participants improved in retrieval accuracy of treated words. Accuracy of untreated words improved for two participants; retrieval accuracy for words with shared features improved slightly more than for words with no-shared features. Two participants showed variable generalization to discourse tasks and improved speed of accurate responses. Clinical implications and future research directions are discussed

Becoming 'ward smart' medical students.

BACKGROUND: A small number of medical students elect to work as health care assistants (HCAs) during or prior to their undergraduate training. There is a significant body of evidence in the literature regarding the impact of HCA experience on student nurses; however, little research has examined the effects of such experience on medical students. METHODS: All fourth-year medical students with self-declared experience as HCAs from a single UK medical school were invited to participate in focus groups to explore their experiences and perceptions. Ten students from the year group took part. RESULTS: Participants felt that their experience as HCAs enhanced their learning in the workplace through becoming 'ward smart', helping them to become socialised into the world of health care, providing early meaningful and humanised patient interaction, and increasing their understanding of multidisciplinary team (MDT) members' roles. Little research has examined the effects of [HCA] experience on medical students DISCUSSION: Becoming 'ward smart' and developing a sense of belonging are central to maximising learning in, from and through work on the ward. Experience as a HCA provides a range of learning and social opportunities for medical students, and legitimises their participation within clinical communities. HCA experience also seems to benefit in the 'hard to reach' dimensions of medical training: empathy; humanisation of patient care; professional socialisation; and providing a sense of belonging within health care environments

Eikonal analysis of Coulomb distortion in quasi-elastic electron scattering

An eikonal expansion is used to provide systematic corrections to the eikonal approximation through order $1/k^2$, where $k$ is the wave number. Electron wave functions are obtained for the Dirac equation with a Coulomb potential. They are used to investigate distorted-wave matrix elements for quasi-elastic electron scattering from a nucleus. A form of effective-momentum approximation is obtained using trajectory-dependent eikonal phases and focusing factors. Fixing the Coulomb distortion effects at the center of the nucleus, the often-used ema approximation is recovered. Comparisons of these approximations are made with full calculations using the electron eikonal wave functions. The ema results are found to agree well with the full calculations.Comment: 12 pages, 6 Postscript figure

Chandra Observations of the Crab-like Supernova Remnant G21.5-0.9

Chandra observations of the Crab-like supernova remnant G21.5-0.9 reveal a compact central core and spectral variations indicative of synchrotron burn-off of higher energy electrons in the inner nebula. The central core is slightly extended, perhaps indicating the presence of an inner wind-shock nebula surrounding the pulsar. No pulsations are observed from the central region, yielding an upper limit of ~40% for the pulsed fraction. A faint outer shell may be the first evidence of the expanding ejecta and blast wave formed in the initial explosion, indicating a composite nature for G21.5-0.9.Comment: 4 pages, 2 figures, formatted with emulateapj, submitted to ApJ