Applications of Electron Backscatter Diffraction (EBSD) in Archaeology

Electron backscattered diffraction (EBSD) has been used to study samples of archaeological gold, silver, copper and bronze prepared using simple metallographic etches. EBSD maps of orientation and local misorientation revealed the metals’ microstructures and deformation substructures, and from this, combined in some cases with information on the crystallographic texture (also determined by EBSD), the methods of manufacture and working of the artefacts were determined. EBSD was also used to examine discontinuous precipitation at grain boundaries in a silver alloy at a high resolution

Using size distributions for determining growth mechanisms of grain boundary precipitates

In the past various single parameters such as the mean, mode or maximum of the precipitate size distribution have been used in experiments to determine growth mechanisms. In the present study the development with aging time of the size and shape distributions of bcc precipitates at grain boundaries in an fcc material (Co-20Fe at 1003oK) have been compared with possible theoretical models to determine the rate controlling process. The growth of these precipitates is initially well described by the grain boundary dependent collector plate mechanism of Brailsford and Aaron. As the precipitates grow low energy facets are formed which can move only by the propagation of ledges and growth becomes interface controlled. The precipitates’ diffusion fields soon overlap and coarsening occurs with interface control. The results demonstrate that this would not have been revealed using simpler measures of precipitate size

Boundary selectivity of crack paths in corrosion fatigue of stainless steel

Stress corrosion and corrosion fatigue cracks are frequently very branched and there have been extensive attempts to define the characteristics of crack-stopping features. EBSD has been used to examine the full length (~8mm) of a corrosion fatigue crack in stainless steel. The grain boundary character distribution of the cracked boundaries is compared to that of the rest of the material and observations presented on the effect of grain boundary character on the choice of crack path at grain boundary junctions of different configurations and orientations with restect to the principle stres

Microstructures of cast silver-copper alloy archaeological artefacts

Cast silver-copper alloys objects form a significant part of the archaeological record from the first millenium BC onwards. Although age hardening of annealed and quenched material has been well studied there has been little study of cast microstructures. This work used a combination of scanning electron microscopy (SEM), electron backscattered diffraction (EBSD) and optical microscopy (OM) to explore the range of microstructures in archaeological cast silver and compare them with those in modern cast silver. Modern cast silver showed extensive fine scale precipitation of copper within the grains which was unconnected to the copper-rich phase of the primary eutectic. Ancient cast objects displayed a wide range of microstructures, some very similar to the modern cast silver but some quite different. EBSD allowed interpretation of the microstructure close to some grain boundaries whose detail was obscured by the cast structure in OM and SEM images. Orientation images showed fine-scale interpenetration of the adjoining grains suggesting cellular growth, suggesting that over archaeological time boundary modification may take place in cast as well as wrought and annealed structures

Women and work in the Fourth Industrial Revolution: An exploratory study of women's experience in IT Jobs

Information and Communication Technology (ICT) is leading the discontinuous change in every sphere of our lives, from the Internet of everything to the Internet of all, and from Artificial Intelligence and Robotics to Human Augmentation. As nations experience shifting sources of competitiveness and a “hollowing out” effect, existing competencies get destroyed and the need for new competencies arises. On one hand, there is an increasing requirement for a workforce with high technical skills and on the other hand there is a shortage of human capital that can meet this need (Choi 2017). Information Technology (IT) is one of the key sectors experiencing this phenomenon. The high gender gap - a constant 72 percent which is estimated to continue in the future – further compounds the problem. IT is seen as a male dominated occupation, as indicated, for example, by the 78 percent:22 percent male-to-female ratio of Artificial Intelligence professionals globally (World Economic Forum 2018). Even amongst the women who do work in the IT profession, studies report a “leaky pipeline” with women moving away from their IT jobs during their career (Vitores & Gil-Juárez 2016). There is an urgent need for understanding the phenomenon of gender representation in the era of the Fourth Industrial Revolution. To this end, the present study explores the experiences of women working in IT departments and organizations in Dubai, their motivations, challenges, coping strategies and organizational support systems. These women have been chosen for the study to compare the experiences of IT versus non-IT women professionals working in the IT field. Neo-classical and human capital theories highlight women’s lower levels of education and workplace experience due to childcare responsibilities. Feminist theories argue that the underlying reason lies in the patriarchal attitudes and structures that perpetuate male domination in society, which extend to the workplace. Gender studies predominantly report challenges and negative experiences that include prejudice, hostility, inequality, stereotyping etc., all of which originate from social conditioning. A gender-neutral axiological stance has been adopted for this study which broadens the understanding of womens’ experiences - both positive and negative - the sources of the challenges as well as the support from the opposite gender as well as same-gender peers, superiors and subordinates; and the elements of social conditioning that aided and those that exacerbated their experiences. The study was undertaken from a yin-and-yang positionality rather than using a gender hierarchy and hence treats both genders as complementing each other. The objective is to help address the service management imperatives of developing an enabling work culture, harnessing the potential of employees and developing a sustainable pipeline of competent professionals, which essentially involves addressing the challenges faced by women and mitigating barriers to their empowered contribution. The approach adopted was a relativist ontological approach that aimed to understand the reality as perceived by women working in IT departments/companies based on their social interactions and experiences. To address the challenges, effective service management strategies must be based on an understanding of women’s subjective reality, a qualitative study marked the first phase of the study. Keywords: Gender gap in services, IT industry, IR4, Experiences, support strategies, coping mechanisms, gender-neutral approac

Evaluating stress physiology and parasite infection parameters in the translocation of critically endangered woylies (Bettongia penicillata)

Translocation can be stressful for wildlife. Stress may be important in fauna translocation because it has been suggested that it can exacerbate the impact of infectious disease on translocated wildlife. However, few studies explore this hypothesis by measuring stress physiology and infection indices in parallel during wildlife translocations. We analysed faecal cortisol metabolite (FCM) concentration and endoparasite parameters (nematodes, coccidians and haemoparasites) in a critically endangered marsupial, the woylie (Bettongia penicillata), 1–3 months prior to translocation, at translocation, and 6 months later. FCM for both translocated and resident woylies was significantly higher after translocation compared to before or at translocation. In addition, body condition decreased with increasing FCM after translocation. These patterns in host condition and physiology may be indicative of translocation stress or stress associated with factors independent of the translocation. Parasite factors also influenced FCM in translocated woylies. When haemoparasites were detected, there was a significant negative relationship between strongyle egg count and FCM. This may reflect the influence of glucocorticoids on the immune response to micro- and macro-parasites. Our results indicate that host physiology and infection patterns can change significantly during translocation, but further investigation is required to determine how these patterns influence translocation success

Constraining the parameters of binary systems through time-dependent light deflection

A theory is derived relating the configuration of the cores of active galaxies, specifically candidates for presumed super-massive black hole binaries (SMBHBs), to time-dependent changes in images of those galaxies. Three deflection quantities, resulting from the monopole term, mass quadrupole term, and spin dipole term of the core, are examined. The resulting observational technique is applied to the galaxy 3C66B. This technique is found to under idealized circumstances surpass the technique proposed by Jenet et al. in accuracy for constraining the mass of SMBHB candidates, but is exceeded in accuracy and precision by Jenet's technique under currently-understood likely conditions. The technique can also under favorable circumstances produce results measurable by currently-available astronomical interferometry such as very-long baseline-interferometry (VLBI).Comment: 15 pages, 2 figures, accepted in General Relativity & Gravitatio

Percutaneous transhepatic cholangiography and biliary drainage after liver transplantation: A five-year experience

Evaluation of the biliary tract by percutaneous transhepatic cholangiography (PTC) is often required in liver transplant patients with an abnormal postoperative course. Indications for PTC include failure of liver enzyme levels to return to normal postoperatively, an elevation of serum bilirubin or liver enzyme levels, suspected bile leak, biliary obstructive symptoms, cholangitis, and sepsis. Over a 5-year period 625 liver transplants in 477 patients were performed at the University Health Center of Pittsburgh. Fifty-three patients (56 transplants) underwent 70 PTCs. Complications diagnosed by PTC included biliary strictures, bile leaks, bilomas, liver abscesses, stones, and problems associated with internal biliary stents. Thirty-two percutaneous transhepatic biliary drainage procedures were performed. Ten transplantation patients underwent balloon dilatation of postoperative biliary strictures. Interventional radiologic techniques were important in treating other complications and avoiding additional surgery in many of these patients. © 1987 Springer-Verlag New York Inc

Next generation sequencing reveals widespread trypanosome diversity and polyparasitism in marsupials from Western Australia

In Western Australia a number of indigenous Trypanosoma spp. infect susceptible native marsupials, such as the woylie (Bettongia penicillata), brushtail possum (Trichosurus vulpecula), and chuditch (Dasyurus geoffroii). Two genotypes of Trypanosoma copemani (identified as G1 and G2) have been found in the woylie, and G2 has been implicated in the decline of this host species, making its presence of particular interest. Here we used targeted amplicon next generation sequencing (NGS) of the Trypanosoma 18S rDNA loci on 70 Trypanosoma-positive marsupial blood samples, to identify T. copemani genotypes and multiple Trypanosoma infections (polyparasitism) in woylies and cohabiting species in Western Australia. Polyparasitism with Trypanosoma spp. was found in 50% of the wildlife sampled, and within species diversity was high, with 85 zero-radius operational taxonomic units (ZOTUs) identified in nine putative parasite species. Trypanosoma copemani was assigned 17 ZOTUs and was identified in 80% of samples. The most abundant ZOTU isolated (63%) differed slightly from the published genotype of G1, and G2 was the second most abundant ZOTU (14%). Trypanosome diversity was significantly greater in woylies than in brushtail possums, and parasite community composition also differed significantly between these host species. One novel Trypanosoma spp. genotype (Trypanosoma sp. ANU2) was found in 20% of samples. A species of Crithidia was detected in a woylie, and two avian trypanosomes (Trypanosoma avium and Trypanosoma sp. AAT) were identified in woylies for the first time