124 research outputs found

    Multi-locus phylogeography of the dusky dolphin (Lagenorhynchus obscurus): passive dispersal via the west-wind drift or response to prey species and climate change?

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    <p>Abstract</p> <p>Background</p> <p>The dusky dolphin (<it>Lagenorhynchus obscurus</it>) is distributed along temperate, coastal regions of New Zealand, South Africa, Argentina, and Peru where it feeds on schooling anchovy, sardines, and other small fishes and squid tightly associated with temperate ocean sea surface temperatures. Previous studies have suggested that the dusky dolphin dispersed in the Southern Hemisphere eastward from Peru via a linear, temperate dispersal corridor provided by the circumpolar west-wind drift. With new mitochondrial and nuclear DNA sequence data, we propose an alternative phylogeographic history for the dusky dolphin that was structured by paleoceanographic conditions that repeatedly altered the distribution of its temperate prey species during the Plio-Pleistocene.</p> <p>Results</p> <p>In contrast to the west-wind drift hypothesis, phylogenetic analyses support a Pacific/Indian Ocean origin, with a relatively early and continued isolation of Peru from other regions. Dispersal of the dusky dolphin into the Atlantic is correlated with the history of anchovy populations, including multiple migrations from New Zealand to South Africa. Additionally, the cooling of the Eastern Equatorial Pacific led to the divergence of anchovy populations, which in turn explains the north-south equatorial transgression of <it>L. obliquidens </it>and the subsequent divergence of <it>L. obscurus </it>in the Southern Hemisphere.</p> <p>Conclusion</p> <p>Overall, our study fails to support the west-wind drift hypothesis. Instead, our data indicate that changes in primary productivity and related abundance of prey played a key role in shaping the phylogeography of the dusky dolphin, with periods of ocean change coincident with important events in the history of this temperate dolphin species. Moderate, short-term changes in sea surface temperatures and current systems have a powerful effect on anchovy populations; thus, it is not infeasible that repeated fluctuations in anchovy populations continue to play an important role in the history of coastal dolphin populations.</p

    The DNS in IoT:Opportunities, Risks, and Challenges

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    The Internet of Things (IoT) is widely expected to make our society safer, smarter, and more sustainable. However, a key challenge remains, which is how to protect users and Internet infrastructure operators from attacks on or launched through vast numbers of autonomously operating sensors and actuators. In this article, we discuss how the security extensions of the domain name system (DNS) offer an opportunity to help tackle that challenge, while also outlining the risks that the IoT poses to the DNS in terms of complex and quickly growing IoT-powered distributed denial of service (DDoS) attacks. We identify three challenges for the DNS and IoT industries to seize these opportunities and address the risks, for example, by making DNS security functions (e.g., response verification and encryption) available on popular IoT operating systems

    EAT 1

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    1. William Slaughter - Like Atlantis 00:27 2. Tim Gilmore - A Saying of Graces 02:57 3. Clark Lunberry & Jason Arnold - Reconsider Now 04:02 4. Keith Cartwright with Jesse Cartwright - Bloomdido 02:08 5. Mark Ari as Cyrano Moon - Under the Influence: Part 1 04:12 6. Clark Lunberry & Jason Arnold - As If / To Drift 03:11 7. William Slaughter - What I Learned Living in an Olive Grove 00:16 8. Mark Ari as Cyrano Moon with Blind Willie Sixpence - I’ll Be Glad When You’re Gone 02:12 9. Clark Lunberry & Jason Arnold - Eavesdropping Across America 05:32 10. Thelma Young - Ria 11:28 11. Christopher Sylvester - Morning Trawl 03:4312. April Fisher - Mine 02:44 13. Tim Gilmore - Leaving Word 07:03 14. K. Hassall - Sabbatical Report: A Compulsory Study in Violence(bonus) 28:06https://digitalcommons.unf.edu/eat/1000/thumbnail.jp

    Fiction Fix 02

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    https://digitalcommons.unf.edu/fiction_fix/1011/thumbnail.jp

    Fiction Fix 03

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    https://digitalcommons.unf.edu/fiction_fix/1012/thumbnail.jp

    Fiction Fix 04

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    https://digitalcommons.unf.edu/fiction_fix/1013/thumbnail.jp

    Fiction Fix 07

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    https://digitalcommons.unf.edu/fiction_fix/1006/thumbnail.jp

    Charge-coupled devices detectors with high quantum efficiency at UV wavelengths

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    We report on multilayer high efficiency antireflection coating (ARC) design and development for use at UV wavelengths on CCDs and other Si-based detectors. We have previously demonstrated a set of single-layer coatings, which achieve >50% quantum efficiency (QE) in four bands from 130 to 300 nm. We now present multilayer coating designs that significantly outperform our previous work between 195 and 215 nm. Using up to 11 layers, we present several model designs to reach QE above 80%. We also demonstrate the successful performance of 5 and 11 layer ARCs on silicon and fused silica substrates. Finally, we present a five-layer coating deposited onto a thinned, delta-doped CCD and demonstrate external QE greater than 60% between 202 and 208 nm, with a peak of 67.6% at 206 nm

    Restoring habitat for fire-impacted species' across degraded Australian landscapes

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    In the summer of 2019-2020, southern Australia experienced the largest fires on record, detrimentally impacting the habitat of native species, many of which were already threatened by past and current anthropogenic land use. A large-scale restoration effort to improve degraded species habitat would provide fire-affected species with the chance to recover and persist in burnt and unburnt habitat. To facilitate this, decision-makers require information on priority species needs for restoration intervention, the suite of potential restoration interventions, and the priority locations for applying these interventions. We prioritize actions in areas where restoration would most likely provide cost-effective benefits to priority species (defined by each species proportion of habitat burned, threat status, and vulnerability to fires), by integrating current and future species habitat suitability maps with spatially modelled costs of restoration interventions such as replanting, removing invasive species, and implementing ecologically appropriate fire management. We show that restoring the top similar to 69% (112 million hectares) of the study region (current and future distributions of priority species) accounts for, on average, 95% of current and future habitat for every priority species and costs similar to AUD73billionyr(1)(AUD73 billion yr(-1) (AUD650 hectare(-1) yr(-1)) annualized over 30 years. This effort would include restoration actions over 6 million hectares of fire-impacted habitat, costing similar to AUD8.8billion/year.Largescalerestorationeffortsareoftencostlybutcanhavesignificantsocietalcobenefitsbeyondbiodiversityconservation.Wealsoshowthatupto291MtCO2(similarto150MtDM)ofcarboncouldbesequesteredbyrestorationefforts,resultinginapproximatelyAUD8.8 billion/year. Large scale restoration efforts are often costly but can have significant societal co-benefits beyond biodiversity conservation. We also show that up to 291 MtCO2 (similar to 150 Mt DM) of carbon could be sequestered by restoration efforts, resulting in approximately AUD253 million yr(-1) in carbon market revenue if all carbon was remunerated. Our approach highlights the scale, costs, and benefits of targeted restoration activities both inside and outside of the immediate bushfire footprint over vast areas of different land tenures

    The Spitzer c2d Survey of Weak-Line T Tauri Stars. III. The Transition from Primordial Disks to Debris Disks

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    We present 3.6 to 70 {\mu}m Spitzer photometry of 154 weak-line T Tauri stars (WTTS) in the Chamaeleon, Lupus, Ophiuchus and Taurus star formation regions, all of which are within 200 pc of the Sun. For a comparative study, we also include 33 classical T Tauri stars (CTTS) which are located in the same star forming regions. Spitzer sensitivities allow us to robustly detect the photosphere in the IRAC bands (3.6 to 8 {\mu}m) and the 24 {\mu}m MIPS band. In the 70 {\mu}m MIPS band, we are able to detect dust emission brighter than roughly 40 times the photosphere. These observations represent the most sensitive WTTS survey in the mid to far infrared to date, and reveal the frequency of outer disks (r = 3-50 AU) around WTTS. The 70 {\mu}m photometry for half the c2d WTTS sample (the on-cloud objects), which were not included in the earlier papers in this series, Padgett et al. (2006) and Cieza et al. (2007), are presented here for the first time. We find a disk frequency of 19% for on-cloud WTTS, but just 5% for off- cloud WTTS, similar to the value reported in the earlier works. WTTS exhibit spectral energy distributions (SEDs) that are quite diverse, spanning the range from optically thick to optically thin disks. Most disks become more tenuous than Ldisk/L* = 2 x 10^-3 in 2 Myr, and more tenuous than Ldisk/L* = 5 x 10^-4 in 4 Myr.Comment: 40 pages, 13 figures, 4 tables. Accepted for publication in ApJ on September 20, 201
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