Investigating the influence of the constituent materials on the performance of periodic piezoelectric composite arrays

This paper describes a theoretical investigation into the influence of the constituent materials on periodic composite array transducer performance. A finite element (FE) model, configured in PZFlex, is used to analyze the performance of a wedge coupled array transducer operating into a steel component. Here, the improvements offered by new single crystal piezoelectric materials are compared to standard PZT‐based configurations. In addition, new passive polymer materials, possessing low longitudinal loss and high shear loss, are evaluated for their potential to significantly reduce inter‐element mechanical cross talk. The FE results illustrate the potential for the next generation of array transducers incorporating these new materials and this is highlighted in the A‐scan predictions from simulated defects

Aflatoxins: Serious threat to food safety and food security: But is it related to livestock?

Globally, crops are being infested with molds. In tropical regions, Aspergillus species commonly occur, some of which produce aflatoxins. Aflatoxins are hepatotoxic, nephrotoxic and carcinogenic to different degrees in livestock as well as humans, causing acute fatal disease as well as chronic illness. Cattle are relatively resistant due to metabolism of toxins in the rumen, while poultry is highly susceptible. Chronic exposure to aflatoxins may cause reduced growth and immunosuppression and is associated with stunting in children and reduced production in livestock. In addition to exposure from crops, metabolites are transferred to breast milk and animal products, especially dairy. Thus, aflatoxins pose health risks to humans when consumed through crops or animal- source food. The impacts of aflatoxins on animal health have consequences on food production and livelihoods of farmers. However, since some animals are less sensitive than humans, feeding contaminated crops to animals diverts it from humans. Livestock may therefore be considered simultaneously as suffering from the toxins, as a way to utilise contaminated products and save humans, and as a potential risk for humans. How does the International Livestock Research Institute (ILRI) approach this complex topic? • Carrying out extensive literature-based reviews and mapping of aflatoxins. • In collaboration with the International Food Policy Research Institute (IFPRI), a series of 2020 policy briefs by leading experts were released in 2013. • The Biosciences eastern and central Africa (BecA)-ILRI Hub has established a shared mycotoxin-research platform in Nairobi, Kenya, that is widely used by partners in the region and beyond. • The BecA-ILRI Hub is working with Kenyan, Tanzanian, other African, Australian and US partners to develop better sampling and diagnostics, develop models and maps of risk and breed, for less susceptible maize varieties. • Projects assessing health risks and economic costs of aflatoxins in the feed dairy chain are underway in Kenya • In collaboration with the International Institute of Tropical Agriculture (IITA), technical packages on aflatoxins and livestock for the East Africa region are being prepared. • Carrying out assessments of the knowledge of, and attitudes to, aflatoxin among milk traders and consumers, and willingness-to-pay for aflatoxin-free milk. • Conducting surveys of aflatoxins in marketed dairy products. • Assessing aflatoxins in commercial pig feed in Uganda and possible effects on growth. With this research portfolio, the complex problem of aflatoxins as a threat to animal and human health, and to food production, security and safety, will be better understood

Serum proteins in healthy and diseased Florida manatees (Trichechus manatus latirostris)

A major goal of this study was to determine whether serum protein fractions of healthy Florida manatees differ with age, sex, or living environments (wild versus housed). A second goal was to determine which serum protein fractions vary in diseased versus healthy manatees. Serum protein fractions were determined using agarose gel electrophoresis. Healthy adults had slightly higher total serum protein and total globulin concentrations than younger animals. This largely resulted from an increase in gamma globulins with age. Total serum protein, albumin, alpha-1 globulin, beta globulin, and total globulin concentrations were slightly higher in housed manatees compared to wild manatees, but there was no significant difference in the albumin/globulin (A/G) ratio, suggesting a difference in hydration between these groups. No significant differences were attributable to sex or pregnancy. Serum albumin concentrations and A/G ratios were significantly lower for manatees with boat trauma, entanglements, emaciation, or cold stress compared to healthy manatees. Variable increases were seen in alpha-1globulins, alpha-2 globulins, beta globulins, and gamma globulins. These globulin fractions contain positive acute-phase proteins and immunoglobulins, and their increases may reflect acute or chronic active inflammation. Changes in serum protein fractions were not consistent enough to justify the use of serum protein electrophoresis as a routine diagnostic test for manatees. However, serum (or plasma) protein electrophoresis is required when accurate values for albumin and globulins are needed in manatees and in determining which protein fractions may account for a hyperproteinemia or hypoproteinemia reported in a clinical chemistry panel

Mission Concept for the Single Aperture Far-Infrared (SAFIR) Observatory

The Single Aperture Far-InfraRed (SAFIR) Observatory's science goals are driven by the fact that the earliest stages of almost all phenomena in the universe are shrouded in absorption by and emission from cool dust and gas that emits strongly in the far-infrared and submillimeter. Over the past several years, there has been an increasing recognition of the critical importance of this spectral region to addressing fundamental astrophysical problems, ranging from cosmological questions to understanding how our own Solar System came into being. The development of large, far-infrared telescopes in space has become more feasible with the combination of developments for the James Webb Space Telescope and of enabling breakthroughs in detector technology. We have developed a preliminary but comprehensive mission concept for SAFIR, as a 10 m-class far-infrared and submillimeter observatory that would begin development later in this decade to meet the needs outlined above. Its operating temperature (<4K) and instrument complement would be optimized to reach the natural sky confusion limit in the far-infrared with diffraction-limited peformance down to at least 40 microns. This would provide a point source sensitivity improvement of several orders of magnitude over that of Spitzer or Herschel, with finer angular resolution, enabling imaging and spectroscopic studies of individual galaxies in the early universe. We have considered many aspects of the SAFIR mission, including the telescope technology, detector needs and technologies, cooling method and required technology developments, attitude and pointing, power systems, launch vehicle, and mission operations. The most challenging requirements for this mission are operating temperature and aperture size of the telescope, and the development of detector arrays.Comment: 36 page

2d Stringy Black Holes and Varying Constants

Motivated by the recent interest on models with varying constants and whether black hole physics can constrain such theories, two-dimensional charged stringy black holes are considered. We exploit the role of two-dimensional stringy black holes as toy models for exploring paradoxes which may lead to constrains on a theory. A two-dimensional charged stringy black hole is investigated in two different settings. Firstly, the two-dimensional black hole is treated as an isolated object and secondly, it is contained in a thermal environment. In both cases, it is shown that the temperature and the entropy of the two-dimensional charged stringy black hole are decreased when its electric charge is increased in time. By piecing together our results and previous ones, we conclude that in the context of black hole thermodynamics one cannot derive any model independent constraints for the varying constants. Therefore, it seems that there aren't any varying constant theories that are out of favor with black hole thermodynamics.Comment: 12 pages, LaTeX, to appear in JHE