An investigation of solubility and diffusion of oxygen in refractory metals Quarterly report, Jan. - Mar. 1966

Solubility and diffusion of oxygen in refractory metals measured by electrical resistivit

Knowing the Double Crested Cormorant: Behavioural Ecology and Public Education of Double-crested Cormorants at Tommy Thompson Park

This project includes both a scientific research paper and a public education poster focused on double-crested cormorants (Phalacrocorax auritus) at Tommy Thompson Park, Toronto, ON. Since my master's includes wildlife ecology and environmental interpretation, I wanted to study cormorants from both scientific and education perspectives. Together with Gail Fraser, I collected observational data on male cormorant advertising displays over the 2014 nesting season. From the results of this behavioural ecology study I wrote a formal scientific research paper which is included in this report. In the literature, cormorant research has been focused primarily on management and topics associated with human-cormorant conflict, leaving a gap in knowledge regarding understanding of basic cormorant behaviours including advertising. Outcomes of my research may have management implications, but my study's primary focus was a greater understanding of cormorant behaviour. A deep understanding of ecological processes, wildlife, and ecosystems is an important foundation for environmental education. Knowledge gained through ecological research enables environmental educators to provide accurate, pertinent information to the general public. With suggestions and advice from Karen McDonald, Park Manager at Tommy Thompson Park, I created a public education poster on cormorants. Cormorants are a controversial bird. Their reputation is clouded by misconceptions and a long history of human-wildlife conflict. Focusing on the same subject from both scientific and education perspectives was rewarding as I was able to practice and facilitate different ways of knowing: I believe that it is by knowing and experiencing the natural world that we can begin to live in right relationship with the land. 1 The Double-Crested Cormorant: The Most Controversial Waterbird on the Great Lakes1 1 The following paragraphs focused on cormorant controversy were adopted from: Mc Rae, M. (2014) Misconceptions and management of the double-crested cormorant. Unpublished manuscript, Applied Ecology, York University, Canada. The double-crested cormorant (Phalacrocorax auritus, hereafter cormorant) is the most controversial waterbird on the Great Lakes. Supported by a long culture history of human-wildlife conflict, current perceptions and attitudes toward cormorants indicate that cormorants' cultural carrying capacity is much lower than their biological carrying capacity (Conover, 2002; Wires & Cuthbert, 2006, p. 9). The greatest sources of conflict include cormorants' landscape transformative presence at nesting sites, their assumed impact on fishing industries, and their perceived impact on co-occurring colonial waterbirds (Weseloh et al., 2002; Wires & Cuthbert, 2010). Although irreversible tree damage occurs at nesting sites, demonstrating this species' impact on fishing industries is complex, and public perception of cormorants as competitors for sport fish is generally not supported by scientific evidence (Andrews, 2008; Duffy, 1995; Bedard, Nadeau, & Lepage, 1995; Koh et al. 2012; Hebert et al., 2005). Also, there is conflicting evidence regarding cormorants' impacts on other colonial nesting species, with the literature recommending site specific analysis (Cuthbert et al., 2002; Somers et al., 2011). Cormorants nesting in the Great Lakes illustrate the importance of identifying ecological interactions and ecological uncertainty as well as the importance of communicating scientific information to the public. Cormorants are native birds that fill a particular niche in the Great Lakes' ecosystem. In my research I strove to construct a scientifically based foundation on which to foster accurate perceptions regarding this controversial bird. This chapter is a result of my background research. 2 In the Great Lakes, the human-cormorant conflict has grown in recent years because of cormorant population expansion (Chastant, King, Weseloh, & Moore, 2014, p. 3; Latta & Faaborg, 2008). As of 2014, cormorant populations on the Great Lakes are expanding beyond previously published numbers, although there is some evidence that expansion may be stabilizing (Weseloh et al., 2002; Chastant et al., 2014). The cormorants' recent population success is largely due to legislative protection, the banning of DDT, and aquaculture expansion in wintering grounds (Cuthbert et al., 2002, p. 151; Boutin et al., 2011; Glahn et al., 1996; Nettleship & Duffy, 1995). On the Great Lakes, cormorant population numbers prior to the 20th century are unknown (Wires & Cuthbert, 2006), but documentation exists for range expansion into the Great Lakes early in the 20th century (Weseloh et al., 1995). Foster and Fraser (2013) suggest that cormorants are a foundation species because of their ability to transform the landscape of their nesting areas. Ecosystems are inherently dynamic, which means change is expected and intrinsic. In the Great Lakes, cormorants typically begin nesting in trees. As their nest building activities and acidic guano destroy the trees, the trees die and fall, and some of the colony begins to nest on the ground (Boutin et al., 2011). Rush, Dobbie, and Fisk (2013) suggest that the effects of altered nutrient levels from cormorant guano can be reduced if cormorants are managed in a low nest density range of ≤ 96 nests ha-1 (p. 306). Other studies indicate that there are non-negative aspects to cormorant habitat modification. A recent study on great cormorants (Phalacrocorax carbo) on a Stockholm archipelago indicated that arthropod diversity and abundance remained largely unaffected by cormorant density (Kolb, Palmborg, & Hamback 2013; Kolb et al., 2012). Also, even when great cormorant presence decreased species richness on a particular island, the resulting change in species composition increased overall archipelago diversity (Kolb et al., 2012). 3 A direct example of interspecies benefit from cormorant habitat modification concerns ground-nesting waterbirds (Leung, 2005; Hatch & Weseloh, 1999). While many migrating songbirds seek dense tree cover for protective resting places, ring-billed gulls (Larus delawarens), common terns (Sterna hirundo), herring gulls (Larus argentatus), and Caspian terns (Hydroprogne caspia) are ground nesting species that benefit from cormorant induced habitat modification (Leung, 2005; Hatch & Weseloh, 1999; Foster & Fraser, 2013). Increased presence of ground nesting birds may alter broader ecosystems by supporting terrestrial carnivore species such as coyotes (Foster & Fraser, 2013). This research suggests that cormorant-induced habitat modification can have positive outcomes. Demonstrating cormorants' impact on fishing industries is complex and involves a public perception that is generally not supported by scientific evidence (e.g. Wires et al. 2003; Duffy, 1995). The highly visible presence of this piscivorous waterbird allows for the perception of appropriately directed blame for depleted fish stocks (Duffy, 1995). Andrews, Fraser, and Weseloh (2012) investigated cormorant fish consumption and prey preference at Tommy Thompson Park, Toronto, Ontario. Although prey competition with sport fish was not considered, and results were biased toward chick diet sampling, researchers concluded that it was improbable that cormorant feeding directly affected the sport fishing industry. The alewife (Alosa pseudoharengus) and round goby (Neogobius melanostomus) are invasive fish species that are common in the Great Lakes and, since the cormorant is opportunistic, the majority of its diet in the Great Lakes is composed of these invasive species (Andrews, Fraser, & Weseloh, 2012; Hatch & Weseloh, 1999; Duffy, 1995). As of 2008, there were four published studies indicating that cormorants negatively impact sport fishing, and eighteen published studies indicating that cormorant predation impacts are negligible (Andrews 2008). Cormorants likely have only a negligible impact on fish populations because it is difficult to demonstrate scientifically that cormorant predation is additive rather than compensatory (Hatch & Weseloh, 1999; Wires et al. 2003). Assumed causation, when correlations between declines in fish populations and increases in cormorant populations are noted, has historically led to aggressive, unscientific management action (Dorr, 2010; Wires et al. 2003). At the population level, negative impacts of cormorants on commercially important fish are not scientifically supported (Duffy, 1995). The rising population of double-crested cormorants has increased the concern that other waterbird species are being displaced because of nest site competition and limited nesting materials. Though it has been reported that irreversible tree damage occurs at nesting sites in less than three years, the literature indicates that this does not correlate with negative impacts on other waterbird species (Cuthbert et al., 2002; Bedard et al., 1995; Koh et al. 2012; Hebert et al., 2005). The concern that cormorants negatively affect co-occurring colonial nesting waterbirds such as black-crowned night herons (Nycticorax nycticorax) and great blue herons (Ardea herodias) on a regional scale is not supported by the past 20 years of scientific documentation (Cuthbert et al., 2002). Research also indicates that the local impact of cormorants is limited (Cuthbert et al., 2002). Due to the inconsistent results attributed to variations in context and species involved, cormorant effects on other colonial waterbirds cannot be generalized as negative. Rather, documentation of interspecies interactions should be collected and results evaluated on a site specific basis to determine if interspecies impacts should factor into local cormorant policy (Cuthbert et al., 2002; Somers et al., 2011). Negative impacts of cormorants on both the Great Lakes' commercially valuable fish and on other waterbirds are not supported by scientific evidence (e.g., Andrews et al. 2012; Duffy, 5 1995; Cuthbert et al., 2002; Duffy 1995; Somers et al., 2011). An in-depth study of the literature indicates that the strong influence of anthropogenic factors on cormorant management comes from public outcry that is based primarily on perceived, rather than documented, impacts (Chastant et al., 2014). Unfortunately, many of the complexities and intricacies of this colonial waterbird are buried under negative folklore. Implications of this background research include the importance of conducting local studies on cormorant impacts as well as the importance of scientifically based cormorant management

Solubility and diffusion of oxygen in tantalum

Solubility of oxygen in tantalum determined by resistivity techniqu

Bore seal technology topical report

Thermophysical, compatibility, and mechanical properties of ceramic-to-metal bore seal material

Nematode associates and susceptibility of a protected slug (Geomalacus maculosus) to four biocontrol nematodes

The impact of selected entomopathogenic nematodes and Phasmarhabditis hermaphrodita on the European-Union-protected slug Geomalacus maculosus and the sympatric Lehmannia marginata was investigated. There was no significant difference in mortality between slugs treated with nematodes and their controls. The presence of P. hermaphrodita in two G. maculosus cadavers may be the result of necromenic behaviour. This study constitutes the first record of P. californica in Europe

The role of single nucleotide polymorphisms in breast cancer metastasis

Our understanding of many aspects of cancer biology has been advanced through the use of modern genetics. These studies have already shown that germ line polymorphisms play a significant role in disease initiation and response to therapy. However, what is less well studied is the role of germ line polymorphisms in cancer progression. Studies in rodents indicate that differential susceptibility to cancer metastasis can be heritable; thus, the search for the genes that control cancer metastasis is underway. Although some provocative studies suggest potential candidates for metastasis regulating genes, the conclusive identification of a specific inherited genetic variant that alters metastatic potential awaits further studies

On the crystallography and composition of topologically close-packed phases in ATI 718Plus®

ATI 718Plus® is a nickel-based superalloy developed to replace Inconel 718 in aero engines for static and rotating applications. Here, the long-term stability of the alloy was studied and it was found that topologically close-packed (TCP) phases can form at the γ-η interface or, less frequently, at grain boundaries. Conventional and scanning transmission electron microscopy techniques were applied to elucidate the crystal structure and composition of these TCP precipitates. The precipitates were found to be tetragonal sigma phase and hexagonal C14 Laves phase, both being enriched in Cr, Co, Fe and Mo though sigma has a higher Cr and lower Nb content. The precipitates were observed to be heavily faulted along multiple planes. In addition, the disorientations between the TCP phases and neighbouring η/γ were determined using scanning precession electron diffraction and evaluated in axis-angle space. This work therefore provides a series of compositional and crystallographic insights that may be used to guide future alloy design.The authors acknowledge Rolls-Royce plc, the EPSRC and the BMWi under grants EP/H022309/1, EP/H500375/1 and 20T0813. P.A.M acknowledges financial support from the European Research Council under the European Union's Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement 291522-3DIMAGE, the Seventh Framework Programme of the European Commission: ESTEEM2, contract number 312483. DNJ acknowledges financial support from the University of Cambridge through the Cambridge Home & EU Scholarship scheme and the EPSRC Cambridge NanoDTC EP/L015978/1

Gamma-gamma prime-gamma double prime dual-superlattice superalloys

Improving the efficiency of gas turbine engines requires the development of new materials capable of operating at higher temperatures and stresses. Here, we report on a new polycrystalline nickel-base superalloy that has exceptional strength and thermal stability. These properties have been achieved through a four-element composition that can form both gamma prime and gamma double prime precipitates in comparable volume fractions, creating an unusual dual-superlattice microstructure. Alloying studies have shown that further property improvements can be achieved, and that with development such alloys may be suitable for future engine applications

Minimization of phonon-tunneling dissipation in mechanical resonators

Micro- and nanoscale mechanical resonators have recently emerged as ubiquitous devices for use in advanced technological applications, for example in mobile communications and inertial sensors, and as novel tools for fundamental scientific endeavors. Their performance is in many cases limited by the deleterious effects of mechanical damping. Here, we report a significant advancement towards understanding and controlling support-induced losses in generic mechanical resonators. We begin by introducing an efficient numerical solver, based on the "phonon-tunneling" approach, capable of predicting the design-limited damping of high-quality mechanical resonators. Further, through careful device engineering, we isolate support-induced losses and perform the first rigorous experimental test of the strong geometric dependence of this loss mechanism. Our results are in excellent agreement with theory, demonstrating the predictive power of our approach. In combination with recent progress on complementary dissipation mechanisms, our phonon-tunneling solver represents a major step towards accurate prediction of the mechanical quality factor.Comment: 12 pages, 4 figure

Multi-species population indices for sets of species including rare, disappearing or newly occurring species

NI is funded by Natural Environment Research Council award NE/R016429/1 as part of the UK-SCAPE programme delivering National Capability.Multi-species indices (MSI) are widely used as ecological indicators and as instruments to inform environmental policies. Many of these indices combine species-specific estimates of relative population sizes using the geometric mean. Because the geometric mean is not defined when values of zero occur, usually only commoner species are included in MSIs and zero values are replaced by a small non-zero value. The latter can exhibit an arbitrary influence on the geometric mean MSI. Here, we show how the compound Poisson and the negative binomial model can be used in such cases to obtain an MSI that has similar features to the geometric mean, including weighting halving and doubling of a species’ population equally. In contrast to the geometric mean, these two statistical models can handle zero values in population sizes and thus accommodate newly occurring and temporarily or permanently disappearing species in the MSI. We compare the MSIs obtained by the two statistical models with the geometric mean MSI and measure sensitivity to changes in evenness and to population trends in rare and abundant species. Additionally, we outline sources of uncertainty and discuss how to measure them. We found that, in contrast to the geometric mean and the negative binomial MSI, the compound Poisson MSI is less sensitive to changes in evenness when total abundance is constant. Further, we found that the compound Poisson model can be influenced more than the other two methods by trends of species showing a low interannual variance. The negative binomial MSI is less sensitive to trends in rare species compared with the other two methods, and similarly sensitive to trends in abundant species as the geometric mean. While the two new MSIs have the advantage that they are not arbitrarily influenced by rare, newly appearing and disappearing species, both do not weight all species equally. We recommend replacing the geometric mean MSI with either compound Poisson or negative binomial when there are species with a population size of zero in some years having a strong influence on the geometric mean MSI. Further, we recommend providing additional information alongside the MSIs. For example, it is particularly important to give an evenness index in addition to the compound Poisson MSI and to indicate the number of disappearing and newly occurring species alongside the negative binomial MSI.Publisher PDFPeer reviewe