2,592 research outputs found
Three-dimensional wakes in linearly stratified liquids.
Massachusetts Institute of Technology. Dept. of Civil Engineering. Thesis. 1966. M.S.MICROFICHE COPY ALSO AVAILABLE IN BARKER ENGINEERING LIBRARY.Bibliography: p. 80.M.S
Plant evolution:Streptophyte multicellularity, ecology, and the acclimatisation of plants to life on land
Land plants are celebrated as one of the three great instances of complex multicellularity, but new phylogenomic and phenotypic analyses are revealing deep evolutionary roots of multicellularity among algal relatives, prompting questions about the causal basis of this major evolutionary transitio
Occurrence of the Brackish Water Asellote Isopod Munna (Uromunna) reynoldsi in Texas
The asellote isopod Munna (Uromunna) reynoldsi Frankenberg and Menzies, previously known from coastal swamps a t Sapelo Island, Georgia, is reported from Texas. Several specimens were collected in grab samples from Fence Lake, a small brackish marsh lake (salinity 0 to 2.7 ppt) in Sca Rim State Park, and in a nearby coastal marsh (salinity 4.4 ppt). The present records indicate that the species is a brackish water form
Occurrence of the Brackish Water Asellote Isopod Munna (Uromunna) reynoldsi in Texas
The asellote isopod Munna (Uromunna) reynoldsi Frankenberg and Menzies, previously known from coastal swamps a t Sapelo Island, Georgia, is reported from Texas. Several specimens were collected in grab samples from Fence Lake, a small brackish marsh lake (salinity 0 to 2.7 ppt) in Sca Rim State Park, and in a nearby coastal marsh (salinity 4.4 ppt). The present records indicate that the species is a brackish water form
Electron impact ionization loading of a surface electrode ion trap
We demonstrate a method for loading surface electrode ion traps by electron
impact ionization. The method relies on the property of surface electrode
geometries that the trap depth can be increased at the cost of more
micromotion. By introducing a buffer gas, we can counteract the rf heating
assocated with the micromotion and benefit from the larger trap depth. After an
initial loading of the trap, standard compensation techniques can be used to
cancel the stray fields resulting from charged dielectric and allow for the
loading of the trap at ultra-high vacuum.Comment: 4 pages, 5 eps figures. Shift in focus, minor correction
Size isn’t everything:rates of genome size evolution, not C value, correlate with speciation in angiosperms
Angiosperms represent one of the key examples of evolutionary success, and their diversity dwarfs other land plants; this success has been linked, in part, to genome size and phenomena such as whole genome duplication events. However, while angiosperms exhibit a remarkable breadth of genome size, evidence linking overall genome size to diversity is equivocal, at best. Here, we show that the rates of speciation and genome size evolution are tightly correlated across land plants, and angiosperms show the highest rates for both, whereas very slow rates are seen in their comparatively species-poor sister group, the gymnosperms. No evidence is found linking overall genome size and rates of speciation. Within angiosperms, both the monocots and eudicots show the highest rates of speciation and genome size evolution, and these data suggest a potential explanation for the megadiversity of angiosperms. It is difficult to associate high rates of diversification with different types of polyploidy, but it is likely that high rates of evolution correlate with a smaller genome size after genome duplications. The diversity of angiosperms may, in part, be due to an ability to increase evolvability by benefiting from whole genome duplications, transposable elements and general genome plasticity
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Consumer attitudes towards production diseases in intensive production systems
Many members of the public and important stakeholders operating at the upper end of the
food chain, may be unfamiliar with how food is produced, including within modern animal
production systems. The intensification of production is becoming increasingly common in
modern farming. However, intensive systems are particularly susceptible to production diseases,
with potentially negative consequences for farm animal welfare (FAW). Previous
research has demonstrated that the public are concerned about FAW, yet there has been little
research into attitudes towards production diseases, and their approval of interventions
to reduce these. This research explores the public’s attitudes towards, and preferences for,
FAW interventions in five European countries (Finland, Germany, Poland, Spain and the
UK). An online survey was conducted for broilers (n = 789), layers (n = 790) and pigs (n =
751). Data were analysed by means of Kruskal-Wallis ANOVA, exploratory factor analysis
and structural equation modelling. The results suggest that the public have concerns regarding
intensive production systems, in relation to FAW, naturalness and the use of antibiotics.
The most preferred interventions were the most “proactive” interventions, namely improved
housing and hygiene measures. The least preferred interventions were medicine-based,
which raised humane animal care and food safety concerns amongst respondents. The
results highlighted the influence of the identified concerns, perceived risks and benefits on
attitudes and subsequent behavioural intention, and the importance of supply chain stakeholders
addressing these concerns in the subsequent communications with the public
Fiber optic temperature sensor
A fiber optic temperature sensor uses a light source which transmits light through an optical fiber to a sensor head at the opposite end of the optical fiber from the light source. The sensor head has a housing coupled to the end of the optical fiber. A metallic reflective surface is coupled to the housing adjacent the end of the optical fiber to form a gap having a predetermined length between the reflective surface and the optical fiber. A detection system is also coupled to the optical fiber which determines the temperature at the sensor head from an interference pattern of light which is reflected from the reflective surface
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