239 research outputs found
The survivorship and water loss of Liometopum luctuosum (Hymenoptera: Formicidae) and Liometopum occidentale (Hymenoptera: Formicidae) exposed to different temperatures and relative humidity.
Two species of velvety tree ants, Liometopum luctuosum Wheeler, and Liometopum occidentale Emery (Hymenoptera: Formicidae), are commonly found in the western Unites States from Washington to southern California. L. luctuosum is restricted to coniferous forests in the mountains in the southern range, whereas L. occidentale is found in the lowlands. The survivorship of workers of both species exposed to several temperatures and relative humidity (RH) was determined. As temperature increased, survival of both species decreased. As the RH increased, survival of both species increased. However, L. luctuosum had higher overall survival in all treatment groups. The cuticular permeability (CP) and the rates of body water loss for each species were determined. Both species had similar CPs. Increased physiological tolerances of L. luctuosum may be an explanation for its broader distribution
A Review of the Biology, Ecology and Behavior of Velvety Tree Ants of North America
Ants belonging to the genus Liometopum are regionally distributed across North America, Europe and Asia. L. apiculatum Mayr, L. luctuosum Wheeler, and L. occidentale Emery are found in western North America and are referred to as velvety tree ants. Very little is known about the biology of these species, but they are similar. They are typically associated with trees and shrubs and are frequently found tending hemipterans. All three species are are easily disturbed and and resort to highly aggressive behaviors including the use of strong alarm odors. The following review is intended to summarize the literature regarding the biology and control of these species. Special emphasis has been given to factors that might be important in their control and gaps in our current knowledge.</span
A Review of the Biology, Ecology and Behavior of Velvety Tree Ants of North America
Ants belonging to the genus Liometopum are regionally distributed across North America, Europe and Asia. L. apiculatum Mayr, L. luctuosum Wheeler, and L. occidentale Emery are found in western North America and are referred to as velvety tree ants. Very little is known about the biology of these species, but they are similar. They are typically associated with trees and shrubs and are frequently found tending hemipterans. All three species are are easily disturbed and and resort to highly aggressive behaviors including the use of strong alarm odors. The following review is intended to summarize the literature regarding the biology and control of these species. Special emphasis has been given to factors that might be important in their control and gaps in our current knowledge
Evaluation of high temperature performance of the Co-Cr-C coated P92 steel
The motivation to increase the operation temperatures of fossil fuel power plant is primarily to improve power plant efficiency and reduce the negative environmental impact of fossil fuel power plant emissions. A main limitation to higher temperature operation is the enhanced oxidation damage of materials at increased temperatures. One of the most concerning areas of enhanced damage is on the inside surface of P92 ferritic steel (~ 9 % Cr) pipework which is used primarily to carry high temperature steam from the boiler.
To combat the oxidation damage of P92 the energy industry has recently begun investigating the application of oxidation resistant coatings to P92 to enable higher temperature operation. Aluminium diffusion coatings have been the focus to date but they have been found to have a number of limitations, including coating degradation/porosity and a detrimental effect on the creep properties of the substrate, in part due to the high temperature coating process. Although other lower temperature coating methods, such as thermal spraying, have been considered these are limited by the practicalities and economics of spraying on the inside surface of P92 pipework. Therefore there is a real industrial need for consideration of a new coating type, for the inside of P92 pipework, which can be applied at low temperature and is also economical at full scale. This is where this thesis contributes by considering an electro-deposited Co-Cr-C coating never previously considered for this application.
The Co-Cr-C type coating is electro-deposited to ~ 34-37 µm onto P92 ferritic steel. The coating is composed of ~ 35 wt % Cr3C2 electro-deposited within a cobalt matrix. The free-standing coating material and coated P92 system were subjected to isothermal oxidation in air and the oxidised state was characterised by a range of microstructural techniques. Oxidation behaviour, microstructural evolution and inter-diffusion between coating and substrate have all been considered. Thermo-Calc thermodynamic software has been used to make predictions about the long term evolution of the system. A series of uncoated and coated mechanical tests (creep, fatigue, creep-fatigue) have also been performed to assess the effect of coating application on the mechanical properties of P92 steel. This research has been motivated by industry at all stages and close collaboration has allowed for the most industrially relevant test conditions to be determined.
Overall the Co-Cr-C coating is shown to be an industrially promising coating technology for application to P92. The study within this thesis shows that the good oxidation properties, interface behaviour and mechanical properties, combined with low temperature deposition and easy scale up, make this a viable coating for further development. It also has a number of advantages over the current aluminium coatings. The work within this thesis serves as a detailed feasibility and industry case study for further in-house testing by industrial sponsors, before future commercialisation of the product. A discussion of potential future work is also included at the end of the thesis
Hidden giants: The story of Bolbometopon muricatum at ningaloo reef
Bolbometopon muricatum (bumphead parrotfish, Valenciennes, 1839) is a conspicuous, iconic and ecologically important coral reef fish species. B. muricatum plays an important role in the bioerosion of the reef framework and as a result has been described as both an ecosystem engineer and keystone species. Despite the complete absence of B. muricatum from 32 years of scientific surveys across the Ningaloo Reef World Heritage Area, we recorded a total of 155 individuals of B. muricatum across 63.2 ha of reef crest surveys, equating to mean density of 2.38 ind/ha. Our observations represent the first record of this iconic species in scientific surveys at Ningaloo and in combination with qualitative observations of B. muricatum by expert witnesses, indicate B. muricatum is likely to have been present in ecologically relevant densities since 2006. The densities of B. muricatum observed at northern Ningaloo in 2021 suggest this species is removing an estimated 13.42 tonnes/ha or 1.34 kg/m2 of calcium carbonate per year, which is broadly comparable with estimates of total parrotfish bioerosion across many reefs in the central Indian and Pacific Oceans. Although not currently afforded elevated conservation status within management plans, B. muricatum possess many life-history characteristics that make them vulnerable to overfishing and may justify consideration for increased protection within the world heritage listed Ningaloo Reef Marine Park
Evaluation of a Command-line Parser-based Order Entry Pathway for the Department of Veterans Affairs Electronic Patient Record
Objective: To improve and simplify electronic order entry in an existing electronic patient record, the authors developed an alternative system for entering orders, which is based on a command- interface using robust and simple natural-language techniques. Design: The authors conducted a randomized evaluation of the new entry pathway, measuring time to complete a standard set of orders, and users' satisfaction measured by questionnaire. A group of 16 physician volunteers from the staff of the Department of Veterans Affairs Puget Sound Health Care System-Seattle Division participated in the evaluation. Results: Thirteen of the 16 physicians (81%) were able to enter medical orders more quickly using the natural-language-based entry system than the standard graphical user interface that uses menus and dialogs (mean time spared, 16.06 ± 4.52 minutes; P=0.029). Compared with the graphical user interface, the command--based pathway was perceived as easier to learn (P<0.01), was considered easier to use and faster (P<0.01), and was rated better overall (P<0.05). Conclusion: Physicians found the command- interface easier to learn and faster to use than the usual menu-driven system. The major advantage of the system is that it combines an intuitive graphical user interface with the power and speed of a natural-language analyze
Hyperproliferation and Dysregulation ofIL-4 Expression in NF-ATp-Deficient Mice
AbstractNF-ATp is a member of a family of genes that encodes the cytoplasmic component of the nuclear factor of activated T cells (NF-AT). In this study, we show that mice with a null mutation in the NF-ATp gene have splenomegaly with hyperproliferation of both B and T cells. They also display early defects in the transcription of multiple genes encoding cytokines and cell surface receptors, including CD40L and FasL. A striking defect in early IL-4 production was observed after ligation of the TCR complex by treatment with anti-CD3 in vivo. The transcription of other cytokines including IL-13, GM–CSF, and TNFα was also affected, though to a lesser degree. Interestingly, the cytokines IL-2 and IFNγ were minimally affected. Despite this early defect in IL-4 transcription, Th2 development was actually enhanced at later timepoints as evidenced by increased IL-4 production and IgE levels in situations that favor the formation of Th2 cells both in vitro and in vivo. These data suggest that NF-ATp may be involved in cell growth, and that it is important for the balanced transcription of the IL-4 gene during the course of an immune response.BDY
- …