Proton-Induced X-Ray Emission Spectrometry in Archaeology

Proton-induced x-ray emission (PIXE) spectrometry is fast developing a reputation as a powerful analytical tool in the study of a range of ancient materials, including bronze, iron, gold, glass, faience, and smelting slag. PIXE data allows determination of the primary constituents which would indicate their recipe of production and determine their bulk physical properties (e.g., color of a glass, brittleness in a metal), and of a wide range of trace elements which may indicate the source of raw material s from which an artifact was constituted. Over the past seven years, PIXE spectrometry\u27s primary advantage over other recognized methods now being applied in archaeological research (particularly, xrf spectrometry and SEM/EDAX) - -that protons induce very little bremsstrahlung and therefore contribute very little to spectrum background during analysis has been much enhanced through the use of various kinds of selective filters in the detection system that heavily suppress the x-ray signal of dominant element(s) in the artifact\u27s matrix (Cu in bronze, Si and Ca in glass, etc.). PIXE detection limits are kept exceptionally low (usually in the 10 ppm to 100 ppm range), because the selective filters almost entirely eliminate secondary background effects arising from response inertia in the detection system\u27s electronics. Archaeological applications of the PIXE method, as reviewed here, now cover both the Old World, the New World, ancient Asia and Polynesia, and a time-span of the 5th millennium B.C. through to the 19th century A.D

Potentials for hyper-Kahler metrics with torsion

We prove that locally any hyper-K\"ahler metric with torsion admits an HKT potential.Comment: 9 page

Autoimmunity associated with chemically induced thymic dysplasia

Thymopoiesis strictly depends on the function of the Foxn1 transcription factor that is expressed in the thymic epithelium. During embryonic development, initial expression of the Foxn1 gene is induced in the pharyngeal endoderm by mesenchyme-derived BMP4 signals. Here, by engineering a time-delayed feedback system of BMP inhibition in mouse embryos, we demonstrate that thymopoiesis irreversibly fails if Foxn1 gene expression does not occur during a defining time span in mid-gestation. We also reveal an epistatic interaction between the extent of BMP signalling and the gene dosage of Foxn1. Our findings illustrate the complexities of the early steps of thymopoiesis and indicate that sporadic forms of thymic hypoplasia in humans may result from the interaction of genes affecting the magnitude of BMP signalling and Foxn1 expressio

Application of PIXE to the study of Renaissance style enamelled gold jewelry

This study examines and compares three pieces of Renaissance style gold and enameled jewelry owned by the Walters Art Gallery, Baltimore, MD, USA. These are a 16th century Hat Badge of Adam and Eve, a 19th century Fortitude Pendant and a Diana Pendant presumed to be of the 16th century (The Walters Art Gallery, Jewelry, Ancient to Modern (Viking, New York, 1979)), Ref. [1]. PIXE spectroscopy was applied to examine the elemental composition of the gold and of the enamels. Compositional differences, including the use of post-Renaissance colorants, were found between the enamels in separate regions of each of the three pieces. The modern colorant, chromium, was, in fact, found in all of the pieces and uranium was found in only the Diana Pendant. There are some differences in the gold purity of the three objects; there are significant differences in the solders used even within one object, the Fortitude Pendant

Is England's public health nutrition system in crisis? A qualitative analysis of the capacity to feed all in need during the COVID-19 pandemic

Methodology: An exploratory methodology was adopted to examine experiences relating to capability and capacity among formal and informal helpers within the PHN domain. An online survey, mainly open-ended questions, was used to capture experiences over the period 2010 - 2020. A mixed sampling strategy, including snowball and convenience sampling, via social media and social network contact-sharing approaches, was adopted. Data was analysed using an inductive thematic approach. Results: A total of 89 participants representing the PHN system in England were recruited over two months. Three main themes and eight sub-themes were identified. The first reflected unequivocal accounts of the impact of austerity and the inability of PHN services to meet demand for food security. The second articulated capacity and capability issues within the system, with geographical variations in service delivery, and a lack of connectivity between central, local government, and third sector providers. These were attributed to widening nutrition and health inequalities. Participants felt that the government needed to invest more technical and financial resources to support public health nutrition. They also felt that schools could play a larger role at local level, but there was a need for a clear national recovery plan, setting out a comprehensive and fully supported national strategy to eradicate food insecurity in England Conclusions: Further in-depth research is needed to continue to track the impact of recovery strategies on food insecure people and the capacity of the PHN system. Urgent investment in the capacity and coordination of PHN services is needed to support food insecure people in England. The UK could include the ratification of the right to food in national laws, in line with global commitments already agreed to by the UK State Party

Potential one-forms for hyperk\"ahler structures with torsion

It is shown that an HKT-space with closed parallel potential 1-form has $D(2,1;-1)$-symmetry. Every locally conformally hyperk\"ahler manifold generates this type of geometry. The HKT-spaces with closed parallel potential 1-form arising in this way are characterized by their symmetries and an inhomogeneous cubic condition on their torsion.Comment: 16 pages, Latex, no figure

The Effect of Moxidectin Treatment on the Equine Hind Gut Microbiome, Metabonome and Feed Fermentation Kinetics in Horses with Very Low Parasite Burdens

Seventeen horses, mean 12 ± 3.5 years, kept at pasture, with haylage provided and no concentrates. Faecal Egg Counts were conducted September 2015‐March 2016, no eggs seen, no anthelmintic given. Sampling commenced March 2016, points were 0 (prior), 16, 48 and 168 hours post anthelmintic. Treatments were randomized, nine animals dosed orally with Moxidectin 18.92 mg/g at 0.4 mg/kg bw and eight controls. Three horses from each group were randomly assigned for fermentation kinetics. Sequencing of the 16S rRNA gene was conducted on extracted faecal bacterial DNA, bioinformatics using QIIME assigning operational taxonomic units (OTUs). LEfSe (Segata et al., 2011) was used to identify differentially abundant OTUs. Bacterial metabolic profiles were characterized by 1H NMR spectroscopy (Escalona et al., 2015), from urine, analysed by Principal Components Analysis. Fermentation of hay and oats, separately, were measured by in vitro gas production (Murray et al., 2006), data were analysed by repeated measures ANOVA

Advances in understanding large-scale responses of the water cycle to climate change

Globally, thermodynamics explains an increase in atmospheric water vapor with warming of around 7%/°C near to the surface. In contrast, global precipitation and evaporation are constrained by the Earth's energy balance to increase at ∼2–3%/°C. However, this rate of increase is suppressed by rapid atmospheric adjustments in response to greenhouse gases and absorbing aerosols that directly alter the atmospheric energy budget. Rapid adjustments to forcings, cooling effects from scattering aerosol, and observational uncertainty can explain why observed global precipitation responses are currently difficult to detect but are expected to emerge and accelerate as warming increases and aerosol forcing diminishes. Precipitation increases with warming are expected to be smaller over land than ocean due to limitations on moisture convergence, exacerbated by feedbacks and affected by rapid adjustments. Thermodynamic increases in atmospheric moisture fluxes amplify wet and dry events, driving an intensification of precipitation extremes. The rate of intensification can deviate from a simple thermodynamic response due to in‐storm and larger‐scale feedback processes, while changes in large‐scale dynamics and catchment characteristics further modulate the frequency of flooding in response to precipitation increases. Changes in atmospheric circulation in response to radiative forcing and evolving surface temperature patterns are capable of dominating water cycle changes in some regions. Moreover, the direct impact of human activities on the water cycle through water abstraction, irrigation, and land use change is already a significant component of regional water cycle change and is expected to further increase in importance as water demand grows with global population

Closed forms and multi-moment maps

We extend the notion of multi-moment map to geometries defined by closed forms of arbitrary degree. We give fundamental existence and uniqueness results and discuss a number of essential examples, including geometries related to special holonomy. For forms of degree four, multi-moment maps are guaranteed to exist and are unique when the symmetry group is (3,4)-trivial, meaning that the group is connected and the third and fourth Lie algebra Betti numbers vanish. We give a structural description of some classes of (3,4)-trivial algebras and provide a number of examples.Comment: 36 page