256 research outputs found

    The Impact of Crown Conch on Intertidal Oyster Populations in Mosquito Lagoon

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    Commercial oyster harvesters in Florida have long complained that the Florida crown conch Melongena coronais in competition with them for harvestable-sized eastern oysters (Crassostrea virginica). Harvesters also suggest that crown conch, rather than overharvesting, has led to a large decline in oyster populations. To determine the role of M. corona on oysters in Mosquito Lagoon, we must first better understand the biology and ecology of M. corona., and to comprehend crown conch biology in Mosquito Lagoon along the east coast of central Florida, we conducted a three-part experiment in Canaveral National Seashore (northern Mosquito Lagoon). Specifically, we designed a field feeding trial to determine prey oyster size preference. To this end, we executed surveys of oyster reefs to gauge the population density of M. corona in Mosquito Lagoon and tracked conch movements in intervals to determine locomotive capabilities. Our results indicate M. corona: 1) was uncommon in Mosquito Lagoon, with the exception of hotspots, 2) did not selectively forage based on tested oyster shell lengths, and 3) moved a mean of 63.5 meters in 24 hours. Based on our abundance data, we estimate that there are 5137 M. corona across 2802 oyster reefs in Mosquito Lagoon (mean: 0.01 conch/m2, with 0.75 conch/m2 in hotspots). More common were thin stripe hermit crabs (Clibanarius vittatus) occupying shells that once housed M. corona. Therefore, it is not likely that M. corona has played a significant role in oyster population declines in Canaveral National Seashore

    High-Resolution Spectral Sleep Analysis Reveals a Novel Association Between Slow Oscillations and Memory Retention in Elderly Adults

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    Objective: In recognition of the mixed associations between traditionally scored slow wave sleep and memory, we sought to explore the relationships between slow wave sleep, electroencephalographic (EEG) power spectra during sleep and overnight verbal memory retention in older adults. Design, Setting, Participants, and Measurements: Participants were 101 adults without dementia (52% female, mean age 70.3 years). Delayed verbal memory was first tested in the evening prior to overnight polysomnography (PSG). The following morning, subjects were asked to recall as many items as possible from the same List (overnight memory retention; OMR). Partial correlation analyses examined the associations of delayed verbal memory and OMR with slow wave sleep (SWS) and two physiologic EEG slow wave activity (SWA) power spectral bands (0.5–1 Hz slow oscillations vs. 1–4 Hz delta activity). Results: In subjects displaying SWS, SWS was associated with enhanced delayed verbal memory, but not with OMR. Interestingly, among participants that did not show SWS, OMR was significantly associated with a higher slow oscillation relative power, during NREM sleep in the first ultradian cycle, with medium effect size. Conclusions: These findings suggest a complex relationship between SWS and memory and illustrate that even in the absence of scorable SWS, older adults demonstrate substantial slow wave activity. Further, these slow oscillations (0.5–1 Hz), in the first ultradian cycle, are positively associated with OMR, but only in those without SWS. Our findings raise the possibility that precise features of slow wave activity play key roles in maintaining memory function in healthy aging. Further, our results underscore that conventional methods of sleep evaluation may not be sufficiently sensitive to detect associations between SWA and memory in older adults

    Crustal Evolution of the Mid-Atlantic Ridge near the Fifteen-Twenty Fracture Zone in the last 5 Ma

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    Author Posting. © American Geophysical Union, 2003. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 4 (2003): 1024, doi:10.1029/2002GC000364.The Mid-Atlantic Ridge around the Fifteen-Twenty Fracture Zone is unique in that outcrops of lower crust and mantle rocks are extensive on both flanks of the axial valley walls over an unusually long distance along-axis, indicating a high ratio of tectonic to magmatic extension. On the basis of newly collected multibeam bathymetry, magnetic, and gravity data, we investigate crustal evolution of this unique section of the Mid-Atlantic Ridge over the last 5 Ma. The northern and southern edges of the study area, away from the fracture zone, contain long abyssal hills with small spacing and fault throw, well lineated and high-amplitude magnetic signals, and residual mantle Bouguer anomaly (RMBA) lows, all of which suggest relatively robust magmatic extension. In contrast, crust in two ridge segments immediately north of the fracture zone and two immediately to the south is characterized by rugged and blocky topography, by low-amplitude and discontinuous magnetization stripes, and by RMBA highs that imply thin crust throughout the last 5 Ma. Over these segments, morphology is typically asymmetric across the spreading axis, indicating significant tectonic thinning of crust caused by faults that have persistently dipped in only one direction. North of the fracture zone, however, megamullions are that thought to have formed by slip on long-lived normal faults are found on both ridge flanks at different ages and within the same spreading segment. This unusual partitioning of megamullions can be explained either by a ridge jump or by polarity reversal of the detachment fault following formation of the first megamullion.This work was completed while T. Fujiwara was a Guest Investigator at Woods Hole Oceanographic Institution with funding from Japan Marine Science and Technology Center (JAMSTEC), National Science Foundation, and the JAMSTEC Research Overseas Program. J. Lin’s contributions to this research were supported by NSF Grant OCE-9811924. B. E. Tucholke’s contributions were supported by NSF Grant OCE-9503561 and by the Andrew W. Mellon Endowment Fund for Innovative Research and the Henry Bryant Bigelow Chair at Woods Hole Oceanographic Institution

    Geographies of responsibility

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    Issues of space, place and politics run deep. There is a long history of the entanglement of the conceptualisation of space and place with the framing of political positions. The injunction to think space relationally is a very general one and, as this collection indicates, can lead in many directions. The particular avenue to be explored in this paper concerns the relationship between identity and responsibility, and the potential georaphies of both

    Deliberate Soccer Practice Modulates Attentional Functioning in Children

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    We thank all the players, parents, coaches, and staff members of Valencia C.F. and the students, parents, and teachers of the Villar Palasí Primary Education School (Sagunto, Spain) for their participation in this research project.The main purpose of this study was to explore the association between the regular practice of open-skill sports (i.e., soccer) and executive control, along with other attentional functions (i.e., alerting and orienting) during preadolescence. The study was conducted on 131 participants (70 non-athletes and 61 soccer players). To measure cognitive performance, participants performed the Attentional Network Test—Interactions (ANT-I) task. Compared to non-athletes, soccer players showed overall faster responses and better executive control (e.g., reduced interference from distractors). Overall, our results provide new empirical evidence supporting the positive association between regular sports practice and cognitive performance, and more specifically executive functions. However, is important to note that the relationship between regular sport practice and cognition is complex and multifactorial. Our findings can be partly explained by the “cardiovascular fitness hypothesis” and the “cognitive component skills approach,” suggesting that an externally paced sport environment with high physical fitness and perceptual–cognitive demands may be an appropriate setting to optimize the development of cognitive functioning during early adolescence.This research was supported by grants from San Vicente Mártir Catholic University of Valencia (2019-158-003 to FH and 2018- 158-004 to CM) and the Spanish Ministry of Economy, Industry and Competitiveness (PSI2017-84926-P) to JL and FH. The funding bodies had no role in the study design, the data collection and analysis, decision to publish, or preparation of the manuscript

    Highly parallel oligonucleotide purification and functionalization using reversible chemistry

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    We have developed a cost-effective, highly parallel method for purification and functionalization of 5′-labeled oligonucleotides. The approach is based on 5′-hexa-His phase tag purification, followed by exchange of the hexa-His tag for a functional group using reversible reaction chemistry. These methods are suitable for large-scale (micromole to millimole) production of oligonucleotides and are amenable to highly parallel processing of many oligonucleotides individually or in high complexity pools. Examples of the preparation of 5′-biotin, 95-mer, oligonucleotide pools of >40K complexity at micromole scale are shown. These pools are prepared in up to ~16% yield and 90–99% purity. Approaches for using this method in other applications are also discussed

    Lava deposition history in ODP Hole 1256D : insights from log-based volcanostratigraphy

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    Author Posting. © American Geophysical Union, 2010. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 11 (2010): Q05003, doi:10.1029/2009GC002933.A log-based volcanic stratigraphy of Ocean Drilling Program Hole 1256D provides a vertical cross-section view of in situ upper crust formed at the East Pacific Rise (EPR) with unprecedented resolution. This stratigraphy model comprises ten electrofacies, principally identified from formation microscanner images. In this study, we build a lava flow stratigraphy model for the extrusive section in Hole 1256D by correlating these electrofacies with observations of flow types from the modern EPR, such as sheet flows and breccias, and pillow lavas and their distribution. The resulting flow stratigraphy model for the Hole 1256D extrusive section represents the first realization of detailed in situ EPR upper oceanic crust construction processes that have been detected only indirectly from remote geophysical data. We correlated the flow stratigraphy model with surface geology observed from the southern EPR (14°S) by Shinkai 6500 dives in order to obtain the relationship between lava flow types and ridge axis-ridge slope morphology. This dive information was also used to give a spatial-time reference frame for modeling lava deposition history in Hole 1256D. In reconstructing the lava deposition history, we interpreted that the origins of the ∼100 m thick intervals with abundant pillow lavas in Hole 1256D are within the axial slope where pillow lavas were observed during the Shinkai 6500 dives and previous EPR surveys. This correlation could constrain the lava deposition history in Hole 1256D crust. Using the lateral scale of ridge axis–ridge slope topography from the Shinkai 6500 observations and assuming the paleospreading rate was constant, 50% of the extrusive rocks in Hole 1256D crust were formed within ∼2000 m of the ridge axis, whereas nearly all of the remaining extrusive section was formed within ∼3000 m of the ridge axis. These results are consistent with the upper crustal construction model previously suggested by seismic studies.S.U. was supported by the Center of Deep Earth Exploration (CDEX) for travel fares and by Monbusho grant-in-aid for research 18540472

    The GALAH Survey: Chemical tagging and chrono-chemodynamics of accreted halo stars with GALAH+ DR3 and GaiaGaia eDR3

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    © 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1093/mnras/stab3504Since the advent of GaiaGaia astrometry, it is possible to identify massive accreted systems within the Galaxy through their unique dynamical signatures. One such system, GaiaGaia-Sausage-Enceladus (GSE), appears to be an early "building block" given its virial mass >1010M> 10^{10}\,\mathrm{M_\odot} at infall (z13z\sim1-3). In order to separate the progenitor population from the background stars, we investigate its chemical properties with up to 30 element abundances from the GALAH+ Survey Data Release 3 (DR3). To inform our choice of elements for purely chemically selecting accreted stars, we analyse 4164 stars with low-α\alpha abundances and halo kinematics. These are most different to the Milky Way stars for abundances of Mg, Si, Na, Al, Mn, Fe, Ni, and Cu. Based on the significance of abundance differences and detection rates, we apply Gaussian mixture models to various element abundance combinations. We find the most populated and least contaminated component, which we confirm to represent GSE, contains 1049 stars selected via [Na/Fe] vs. [Mg/Mn] in GALAH+ DR3. We provide tables of our selections and report the chrono-chemodynamical properties (age, chemistry, and dynamics). Through a previously reported clean dynamical selection of GSE stars, including 30<JR / kpckms1<5530 < \sqrt{J_R~/~\mathrm{kpc\,km\,s^{-1}}} < 55, we can characterise an unprecedented 24 abundances of this structure with GALAH+ DR3. Our chemical selection allows us to prevent circular reasoning and characterise the dynamical properties of the GSE, for example mean JR / kpckms1=2614+9\sqrt{J_R~/~\mathrm{kpc\,km\,s^{-1}}} = 26_{-14}^{+9}. We find only (29±1)%(29\pm1)\% of the GSE stars within the clean dynamical selection region. Our methodology will improve future studies of accreted structures and their importance for the formation of the Milky Way.Peer reviewedFinal Accepted Versio

    Quantitative first principles calculations of protein circular dichroism in the near-ultraviolet

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    Vibrational structure in the near-UV circular dichroism (CD) spectra of proteins is an important source of information on protein conformation and can be exploited to study structure and folding. A fully quantitative theory of the relationship between protein conformation and optical spectroscopy would facilitate deeper interpretation and insights into biophysical and simulation studies of protein dynamics and folding. We have developed new models of the aromatic side chain chromophores toluene, p-cresol and 3-methylindole, which incorporate ab initio calculations of the Franck-Condon effect into first principles calculations of CD using an exciton approach. The near-UV CD spectra of 40 proteins are calculated with the new parameter set and the correlation between the computed and the experimental intensity from 270 to 290 nm is much improved. The contribution of individual chromophores to the CD spectra has been calculated for several mutants and in many cases helps rationalize changes in their experimental spectra. Considering conformational flexibility by using families of NMR structures leads to further improvements for some proteins and illustrates an informative level of sensitivity to side chain conformation. In several cases, the near-UV CD calculations can distinguish the native protein structure from a set of computer-generated misfolded decoy structures

    Producing morphologically complex words: An ERP study with children and adults

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    A widely studied morphological phenomenon in psycholinguistic research is the plurals-inside-compounds effect in English, which is the avoidance of regular plural modifiers within compounds (e.g., *rats hunter). The current study employs event-related brain potentials (ERPs) to investigate the production of plurals-inside-compounds in children and adults. We specifically examined the ERP correlates of producing morphologically complex words in 8-year-olds, 12-year-olds and adults, by recording ERPs during the silent production of compounds with plural or singular modifiers. Results for both children and adults revealed a negativity in response to compounds produced from regular plural forms when compared to compounds formed from irregular plurals, indicating a highly specific brain response to a subtle linguistic contrast. Although children performed behaviourally with an adult-like pattern in the task, we found a broader distribution and a considerably later latency in children's brain potentials than in adults’, indicating that even in late childhood the brain networks involved in language processing are subject to subtle developmental changes
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