Wire winding increases lifetime of oxide coated cathodes

Refractory-metal heater base wound with a thin refractory metal wire increases the longevity of oxide-coated cathodes. The wire-wound unit is impregnated with the required thickness of metal oxide. This cathode is useful in magnetohydrodynamic systems and in electron tubes

Operation of a forced circulation, croloy 9 m, mercury loop to study corrosion product separation techniques

Forced circulation, Croloy 9M mercury loop designed to investigate corrosion product separation technique

Ophthalmic method and apparatus

A method and apparatus for removing material and components such as the lens from an eye is described. High speed rotary cutting members at one end of a rod macerate the lens while an annular tubing disposed around the cutting members vibrates ultrasonically to coact with the cutting members in macerating the lens. At the same time, a liquid is supplied to the chamber behind the cornea of the eye. Spiral grooves extending along the rotating rod from the cutting members evacuate the liquid and the macerated material from the eye. An alternate embodiment of the apparatus includes a tube through which liquid is supplied to the operative site of the ultrasonically vibrating tube and the cutting members in the area of the lens

Wind energy developments in the 20th century

Wind turbine systems of the past are reviewed and wind energy is reexamined as a future source of power. Various phases and objectives of the Wind Energy Program are discussed. Conclusions indicate that wind generated energy must be considered economically competitive with other power production methods

Tissue holder for experimental and Demonstration Surgery

Development of device for holding anatomical tissues during operations is discussed. Device consists of plastic dish with hemispherical recess in center to hold excised eyes. Low vacuum applied to underside of recess insures holding of part

Resilience Management: A Framework for Assessing and Improving the Resilience of Organisations

Resilient Organisations Research Report 2007/01Organisations today are increasingly aware of the need to prepare for the unexpected. High profile international events of the last decade, such as the September 11th terrorist attacks, the Indian Ocean tsunami, Hurricane Katrina and the emerging threat of a pandemic all serve to remind organisations that the unimaginable can and does happen. Stories emerge from these events of organisations that survived or failed; at first glance there does not appear to be a particular pattern. Some survivors had excellent disaster response plans in place; others had none, surviving purely on the merits of strong leadership and the commitment and determination of staff. Many organisations that are devastated simply never reopen again; others evolve so radically that they are hard to recognise from their pre-crisis form. This research project seeks to explore what it is that makes some organisations more able to survive a major crisis than others, and suggests a framework for both evaluating and improving the resilience of individual organisations

Wolbachia infections in native and introduced populations of fire ants (Solenopsis spp.)

Wolbachia are cytoplasmically inherited bacteria that induce a variety of effects with fitness consequences on host arthropods, including cytoplasmic incompatibility, parthenogenesis, male-killing and feminization. We report here the presence of Wolbachia in native South American populations of the fire ant Solenopsis invicta, but the apparent absence of the bacteria in introduced populations of this pest species in the USA. The Wolbachia strains in native S. invicta are of two divergent types (A and B), and the frequency of infection varies dramatically between geographical regions and social forms of this host. Survey data reveal that Wolbachia also are found in other native fire ant species within the Solenopsis saevissima species complex from South America, including S. richteri. This latter species also has been introduced in the USA, where it lacks Wolbachia. Sequence data reveal complete phylogenetic concordance between mtDNA haplotype in S. invicta and Wolbachia infection type (A or B). In addition, the mtDNA and associated group A Wolbachia strain in S. invicta are more closely related to the mtDNA and Wolbachia strain found in S. richteri than they are to the mtDNA and associated group B Wolbachia in S. invicta. These data are consistent with historical introgression of S. richteri cytoplasmic elements into S. invicta populations, resulting in enhanced infection and mtDNA polymorphisms in S. invicta. Wolbachia may have significant fitness effects on these hosts (either directly or by cytoplasmic incompatibility) and therefore these microbes potentially could be used in biological control programmes to suppress introduced fire ant populations

Simulation of a storm event in marine microcosms

A storm of moderate intensity and lasting for 14 hours was simulated in three of the Marine Ecosystems Research Laboratory (MERL) microcosms by increasing the intensity of microcosm mixing. The simulation resuspended ~0.3 cm of sediment and increased suspended particulate loads by 2 orders of magnitude. Concurrently, the concentrations of metals and nutrients increased in the water column...

Colony Breeding Structure of Reticulitermes (Isoptera: Rhinotermitidae) in Northwest Arkansas

Termites, as social insects, have a complicated life cycle in which the colony breeding structure, that is the number of and origin of reproductives in a colony, can vary in relation to age and environmental factors. In this study, we used genetic methods to characterize the breeding structure of three species of Reticulitermes from three sites in northwest Arkansas and compared two habitats: undeveloped, forested sites and developed, agricultural sites. We found 57.1% of R. flavipes (Kollar) in northwest Arkansas (n = 28) were simple families, 39.3% were extended families and 3.6% were mixed families. Similarly, for R. hageni Banks (n = 23), we found 58.3% simple families, 33.3% extended families, and 8.3% mixed families. All of the R. virginicus (Banks) samples (n = 5) were simple families. For R. flavipes and R. hageni, the percentage of extended families is intermediate to southeastern and northern USA populations, corresponding to the intermediate seasonality and climate in Arkansas. The level of inbreeding in Arkansas, estimated via FIT, was relatively high and similar to northern populations of Reticulitermes. There were significantly more extended family colonies at the developed site compared to the two undeveloped sites which contained more simple family colonies. This difference may occur as a strategy to cope with sparse resources in urban environments or as a consequence of different abiotic factors