Factors influencing foraging decisions in ruddy turnstones Arenaria interpres (L.)

Animals must assimilate energy to survive and reproduce, but foraging conflicts with other demands on an animal's time. We know very little about how animals resolve these conflicts in natural settings. I studied foraging choices made by ruddy turnstones Arenaria interpres (L.) using rocky coastline in north-east England. In particular I explored how foraging decisions varied with resource quality, the predictability of patch appearance, and perceived predation risk while using alternative patches. This study includes the first quantitative investigation into the use of beach-cast wrack by shorebirds. Energy intake per unit time by foragers on supratidal habitats was much higher than on intertidal habitats. However, birds exclusively used intertidal habitats when these were exposed by the tide, and moved onto supratidal habitats only over the high-water period. Moreover, the number of birds feeding over a given high tide did not depend on supratidal food availability. These results suggested that there were costs to foraging supratidally. Were some foragers being forced to pay these costs because of low foraging efficiency, or did some accept the costs because of other associated benefits? The use of supratidal habitats appeared to incur elevated predation risk for foragers; they were situated in areas where raptors could approach a foraging flock relatively closely before being detected. Accordingly, vigilance was much higher than expected on supratidal habitats, and increased with distance from the water's edge. Birds that regularly fed supratidally tended to be males, older and higher-ranking, and had smaller, less patchy home ranges than birds that rarely fed supratidally. This suggests that some birds were paying the cost of elevated predation risk associated with supratidal feeding for the benefits of stable group membership and higher social status, while others minimised their need for supratidal feeding by spatially tracking the variation in intertidal habitat quality

The Opinion - Vol. 06, No. 03

Originally published in print for Fuller Theological Seminary\u27s community from 1962 through 1977.https://digitalcommons.fuller.edu/fts-opinion/1045/thumbnail.jp

The Opinion - Vol. 05, No. 07

Originally published in print for Fuller Theological Seminary\u27s community from 1962 through 1977.https://digitalcommons.fuller.edu/fts-opinion/1037/thumbnail.jp

The Opinion - Vol. 05, No. 06

Originally published in print for Fuller Theological Seminary\u27s community from 1962 through 1977.https://digitalcommons.fuller.edu/fts-opinion/1036/thumbnail.jp

A national scale inventory of resource provision for biodiversity within domestic gardens

The human population is increasingly disconnected from nature due to urbanisation. To counteract this phenomenon, the UK government has been actively promoting wildlife gardening. However, the extent to which such activities are conducted and the level of resource provision for biodiversity (e.g., food and nesting sites) within domestic gardens remains poorly documented. Here we generate estimates for a selection of key resources provided within gardens at a national scale, using 12 survey datasets gathered across the UK. We estimate that 22.7 million households (87% of homes) have access to a garden. Average garden SiZe is 190 m(2), extrapolating to a total area of 432,924 ha. Although substantial, this coverage is still an order of magnitude less than that of statutory protected areas. Approximately 12.6 million (48%) households provide supplementary food for birds, 7.4 million of which specifically use bird feeders. Similarly, there are a minimum of 4.7 million nest boxes within gardens. These figures equate to one bird feeder for every nine potentially feeder-using birds in the UK, and at least one nest box for every six breeding pairs of cavity nesting birds. Gardens also contain 2.5-3.5 million ponds and 28.7 million trees, which is just under a quarter of all trees occurring outside woodlands. Ongoing urbanisation, characterised by increased housing densities, is inevitable throughout the UK and elsewhere. The important contribution domestic gardens make to the green space infrastructure in residential areas must be acknowledged, as their reduction will impact biodiversity conservation, ecosystem services, and the well-being of the human population

125 - 211 GHz low noise MMIC amplifier design for radio astronomy

To achieve the low noise and wide bandwidth required for millimeter wavelength astronomy applications, superconductor-insulator-superconductor (SIS) mixer based receiver systems have typically been used. This paper investigates the performance of high electron mobility transistor (HEMT) based low noise amplifiers (LNAs) as an alternative approach for systems operating in the 125 — 211 GHz frequency range. A four-stage, common-source, unconditionally stable monolithic microwave integrated circuit (MMIC) design is presented using the state-of-the-art 35 nm indium phosphide HEMT process from Northrop Grumman Corporation. The simulated MMIC achieves noise temperature (T_e) lower than 58 K across the operational bandwidth, with average T_e of 38.8 K (corresponding to less than 5 times the quantum limit (hf/k) at 170 GHz) and forward transmission of 20.5 ± 0.85 dB. Input and output reflection coefficients are better than -6 and -12 dB, respectively, across the desired bandwidth. To the authors knowledge, no LNA currently operates across the entirety of this frequency range. Successful fabrication and implementation of this LNA would challenge the dominance SIS mixers have on sub-THz receivers

A Survey of Action-Learning Opportunities

This is a preliminary report on a survey of Action-Learning opportunities conducted in the Spring of 1972. The survey director was Allan Cameron; a grant from the White House Committee on Youth enabled a number of persons age 15-20 to participate in the surve

Achieving open access to conservation science

Conservation science is a crisis discipline in which the results of scientific enquiry must be made available quickly to those implementing management. We assessed the extent to which scientific research published since the year 2000 in 20 conservation science journals is publicly available. Of the 19,207 papers published, 1,667 (8.68%) are freely downloadable from an official repository. Moreover, only 938 papers (4.88%) meet the standard definition of open access in which material can be freely reused providing attribution to the authors is given. This compares poorly with a comparable set of 20 evolutionary biology journals, where 31.93% of papers are freely downloadable and 7.49% are open access. Seventeen of the 20 conservation journals offer an open access option, but fewer than 5% of the papers are available through open access. The cost of accessing the full body of conservation science runs into tens of thousands of dollars per year for institutional subscribers, and many conservation practitioners cannot access pay-per-view science through their workplace. However, important initiatives such as Research4Life are making science available to organizations in developing countries. We urge authors of conservation science to pay for open access on a per-article basis or to choose publication in open access journals, taking care to ensure the license allows reuse for any purpose providing attribution is given. Currently, it would cost $51 million to make all conservation science published since 2000 freely available by paying the open access fees currently levied to authors. Publishers of conservation journals might consider more cost effective models for open access and conservation-oriented organizations running journals could consider a broader range of options for open access to nonmembers such as sponsorship of open access via membership fees

Theology, News and Notes - Vol. 35, No. 02

Theology News & Notes was a theological journal published by Fuller Theological Seminary from 1954 through 2014.https://digitalcommons.fuller.edu/tnn/1100/thumbnail.jp