17 research outputs found
Climate change, coral loss, and the curious case of the parrotfish paradigm: Why don't marine protected areas improve reef resilience?
Scientists have advocated for local interventions, such as creating marine protected areas and implementing fishery restrictions, as ways to mitigate local stressors to limit the effects of climate change on reef-building corals. However, in a literature review, we find little empirical support for the notion of managed resilience. We outline some reasons for why marine protected areas and the protection of herbivorous fish (especially parrotfish) have had little effect on coral resilience. One key explanation is that the impacts of local stressors (e.g., pollution and fishing) are often swamped by the much greater effect of ocean warming on corals. Another is the sheer complexity (including numerous context dependencies) of the five cascading links assumed by the managed-resilience hypothesis. If reefs cannot be saved by local actions alone, then it is time to face reef degradation head-on, by directly addressing anthropogenic climate change - the root cause of global coral decline
Effect of synthesis conditions on the morphology and crystal structure of biferroic Bi5Ti3FeO15
Citrate-stabilized spherical silver nanoparticles (Ag NPs) with d=8.25 1.25nm diameter were prepared and functionalized with l-cysteine (Cys) in aqueous dispersion. The nanosilver-cysteine interactions have been investigated by Raman and 1H NMR spectroscopy. The effect of pH on stability of biofunctionalized Ag NPs was investigated. The cysteine-capped nanosilver dispersions remain stable at higher pH (pH>7), while the degree of aggregation increased as the pH decreased. Below pH ?7, the characteristic surface plasmon band of bare silver nanoparticles was back-shifted from ?measuredbareAgNP=391 nm to ?measured1=387-391 nm, while the presence of a new band at ?measured2=550-600 nm was also observed depending on pH. Finite element method (FEM) was applied to numerically compute the absorption spectra of aqueous dispersions containing bare and cysteine-functionalized Ag NPs at different pH. Both the dynamic light scattering (DLS) measurements, Zeta potential values and the transmission electron microscopic (TEM) images confirmed our supposition. Namely, electrostatic interaction arose between the deprotonated carboxylate (COO -) and protonated amino groups (NH 3 +) of the amino acid resulting in cross-linking network of the Ag NPs between pH ?3 and 7. If the pH is measurable lower than ?3, parallel with the protonation of citrate and l-cysteine molecules the connection of the particles via l-cysteine is partly decomposed resulting in decrease of second plasmon band intensity. " 2012 Elsevier B.V.",,,,,,"10.1016/j.colsurfb.2012.03.036",,,"http://hdl.handle.net/20.500.12104/40984","http://www.scopus.com/inward/record.url?eid=2-s2.0-84861468429&partnerID=40&md5=403989d81bf95c0f723436c19354e1b9",,,,,,,,"Colloids and Surfaces B: Biointerfaces",,"4
Relative sea-level change in South Florida during the past ~5 ka
A paucity of detailed relative sea-level (RSL) reconstructions from low latitudes hinders efforts to understand the global, regional, and local processes that cause RSL change. We reconstruct RSL change during the past ~5 ka using cores of mangrove peat at two sites (Snipe Key and Swan Key) in the Florida Keys. Remote sensing and field surveys established the relationship between peat-forming mangroves and tidal elevation in South Florida. Core chronologies are developed from age-depth models applied to 72 radiocarbon dates (39 mangrove wood macrofossils and 33 fine-fraction bulk peat). RSL rose 3.7 m at Snipe Key and 5.0 m at Swan Key in the past 5 ka, with both sites recording the fastest century-scale rate of RSL rise since ~1900 CE (~2.1 mm/a). We demonstrate that it is feasible to produce near-continuous reconstructions of RSL from mangrove peat in regions with a microtidal regime and accommodation space created by millennial-scale RSL rise. Decomposition of RSL trends from a network of reconstructions across South Florida using a spatio-temporal model suggests that Snipe Key was representative of regional RSL trends, but Swan Key was influenced by an additional local-scale process acting over at least the past five millennia. Geotechnical analysis of modern and buried mangrove peat indicates that sediment compaction is not the local-scale process responsible for the exaggerated RSL rise at Swan Key. The substantial difference in RSL between two nearby sites highlights the critical need for within-region replication of RSL reconstructions to avoid misattribution of sea-level trends, which could also have implications for geophysical modeling studies using RSL data for model tuning and validation
Behavior of intruder based states in light Bi and Tl isotopes: the study of Bi decay
The excitation energies of the single-particle normal and intruder
levels in both Tl and Bi were measured for the first time via
the decay of Bi produced in the
Mo(Mo,pn)Bi reaction. The previously unobserved
Bi ground state (h) to Tl ground state (s)
transition was identified, establishing the Bi intruder state
excitation energy to be 112(21) keV, 70 keV less than that of the same level in
Bi
Numerical relativity simulations in the era of the Einstein Telescope
Numerical-relativity (NR) simulations of compact binaries are expected to be an invaluable tool in gravitational-wave (GW) astronomy. The sensitivity of future detectors such as the Einstein Telescope (ET) will place much higher demands on NR simulations than first- and second-generation ground-based detectors. We discuss the issues facing compact-object simulations over the next decade, with an emphasis on estimating where the accuracy and parameter space coverage will be sufficient for ET and where significant work is needed. <br/
Proton and α radioactivity below the Z=82 shell closure
none21Ground and isomeric proton and alpha decay branches are reported for the new isotope 177Tl, produced by bombarding a 102Pd target with a 370 MeV beam of 78Kr ions. The ground state is assigned as a πs1/2 configuration and the high spin isomer is assigned as a (πh11/2)-1 configuration. The ground-state proton decay of 171Au has been identified for the first time, produced by bombarding a 96Ru target with 78Kr ions. The 171Au ground state is also assigned as a πs1/2 configuration. Spectroscopic factors, masses, and proton separation energies are derived using these new proton decay measurements. New ground-state α decays for 169Ir and 173Au are also reported.noneG. Poli;C. Davids;P. Woods;D. Seweryniak;J. Batchelder;L. Brown;C. Bingham;M. Carpenter;L. Conticchio;T. Davinson;J. DeBoer;S. Hamada;D. Henderson;R. Irvine;R. Janssens;H. Maier;L. Müller;F. Soramel;K. Toth;W. Walters;J. WautersG., Poli; C., Davids; P., Woods; D., Seweryniak; J., Batchelder; L., Brown; C., Bingham; M., Carpenter; L., Conticchio; T., Davinson; J., Deboer; S., Hamada; D., Henderson; R., Irvine; R., Janssens; H., Maier; L., Müller; Soramel, Francesca; K., Toth; W., Walters; J., Wauter