423 research outputs found
Two decades of carbonate budget change on shifted coral reef assemblages: are these reefs being locked into low net budget states?
This is the author accepted manuscript. The final version is available from the Royal Society via the DOI in this recordThe ecology of coral reefs is rapidly shifting from historical baselines. One key-question is
whether under these new, less favorable ecological conditions, coral reefs will be able to
sustain key geo-ecological processes such as the capacity to accumulate carbonate
structure. Here, we use data from 34 Caribbean reef sites to examine how the carbonate
production, net erosion, and net carbonate budgets, as well as the organisms underlying
these processes, have changed over the past 15 years in the absence of further severe
acute disturbances. We find that despite fundamental benthic ecological changes, these
ecologically shifted coral assemblages have exhibited a modest but significant increase in
their net carbonate budgets over the past 15 years. However, contrary to expectations this
trend was driven by a decrease in erosion pressure, largely resulting from changes in the
abundance and size-frequency distribution of parrotfishes, and not by an increase in rates
of coral carbonate production. Although in the short term the carbonate budgets seem to
have benefitted marginally from reduced parrotfish erosion, the absence of these key
substrate grazers, particularly of larger individuals, is unlikely to be conducive to reef
recovery and will thus likely lock these reefs into low budget states.Universidad Nacional Autónoma de MéxicoRoyal SocietyMexican Council of Science and Technology (CONACYT
Structure-from-motion photogrammetry demonstrates variability in coral growth within colonies and across habitats
This is the final version. Available from Public Library of Science via the DOI in this record. Data Availability Statement: The raw data table is
available from the University of Exeter Repository
ORE at https://doi.org/10.24378/exe.4285Coral growth is an important metric of coral health and underpins reef-scale functional attributes such as structural complexity and calcium carbonate production. There persists, however, a paucity of growth data for most reef-building regions, especially for coral species whose skeletal architecture prevents the use of traditional methods such as coring and Alizarin staining. We used structure-from-motion photogrammetry to quantify a range of colony-scale growth metrics for six coral species in the Mexican Caribbean and present a newly developed workflow to measure colony volume change over time. Our results provide the first growth metrics for two species that are now major space occupiers on Caribbean reefs, Agaricia agaricites and Agaricia tenuifolia. We also document higher linear extension, volume increase and calcification rates within back reef compared to fore reef environments for four other common species: Orbicella faveolata, Porites astreoides, Siderastrea siderea and Pseudodiploria strigosa. Linear extension rates in our study were lower than those obtained via computed tomography (CT) scans of coral cores from the same sites, as the photogrammetry method averages growth in all dimensions, while the CT method depicts growth only along the main growth axis (upwards). The comparison of direct volume change versus potential volume increase calculated from linear extension emphasizes the importance of assessing whole colony growth to improve calcification estimates. The method presented here provides an approach that can generate accurate calcification estimates alongside a range of other whole-colony growth metrics in a non-invasive way.British Ecological Societ
Quark masses and mixings in the RS1 model with a condensing 4th generation
We study the hierarchy of quark masses and mixings in a model based on a
5-dimensional spacetime with constant curvature of Randall-Sundrum type with
two branes, where the Electroweak Symmetry Breaking is caused dynamically by
the condensation of a 4th generation of quarks, due to underlying physics from
the 5D bulk and the first KK gluons. We first study the hierarchy of quark
masses and mixings that can be obtained from purely adjusting the profile
localizations, finding that realistic masses are not reproduced unless non
trivial hierarchies of underlying 4-fermion interactions from the bulk are
included. Then we study global U(1) symmetries that can be imposed in order to
obtain non-symmetric modified Fritzsch-like textures in the mass matrices that
reproduce reasonably well quark masses and CKM mixings.Comment: Minor changes. Version accepted for publication in JHE
Non-L\'evy mobility patterns of Mexican Me'Phaa peasants searching for fuelwood
We measured mobility patterns that describe walking trajectories of
individual Me'Phaa peasants searching and collecting fuelwood in the forests of
"La Monta\~na de Guerrero" in Mexico. These one-day excursions typically follow
a mixed pattern of nearly-constant steps when individuals displace from their
homes towards potential collecting sites and a mixed pattern of steps of
different lengths when actually searching for fallen wood in the forest.
Displacements in the searching phase seem not to be compatible with L\'evy
flights described by power-laws with optimal scaling exponents. These findings
however can be interpreted in the light of deterministic searching on heavily
degraded landscapes where the interaction of the individuals with their scarce
environment produces alternative searching strategies than the expected L\'evy
flights. These results have important implications for future management and
restoration of degraded forests and the improvement of the ecological services
they may provide to their inhabitants.Comment: 15 pages, 4 figures. First version submitted to Human Ecology. The
final publication will be available at http://www.springerlink.co
Pleiotropic functions of the tumor- and metastasis-suppressing Matrix Metalloproteinase-8 in mammary cancer in MMTV-PyMT transgenic mice
Matrix metalloproteinase-8 (MMP-8; neutrophil collagenase) is an important regulator of innate immunity which has onco-suppressive actions in numerous tumor types
Dose-related effects of MDMA on psychomotor function and mood before, during, and after a night of sleep loss
Shrike predation on the lizard Mesalina adramitana in Qatar; a review of reported reptile and amphibian prey
We report, for the first time, evidence of predation by a shrike (Lanius sp.) on the lizard Mesalina adramitana. This is the first record of predation by shrikes on lizards in Qatar. Whilst we did not directly observe the event, the presence of shrikes in the area and the method of impalement indicate shrikes as the predator. The lizard was found freshly impaled on a palm tree (Phoenix dactylifera), at 150 cm above ground. Bird species of the genus Lanius are well-known predators of lizards, and in arid environments reptiles are likely common prey for these birds. We provide a review of literature concerning predatory events by shrikes on reptiles and amphibians. We suggest inspection of shrubs for animals impaled by shrikes can improve biodiversity inventories, complementing other commonly used methods
Lateral variability of ichnological content in muddy contourites: Weak bottom currents affecting organisms’ behavior
Although bioturbation is commonly recognized in contourites, only a few studies have analyzed the
ichnological content of these deposits in detail. These studies have mainly focused on meso-scale
bigradational sequence (a coarsening upward followed by a fining-upward sequence resulting from
variations in current velocity). Here we present data from gravitational cores collected along the
NW Iberian Margin showing systematic variation in ichnological content across proximal to distal
depocenters within a large-scale elongated contourite drift. Data demonstrate that tracemakers’
behavior varies depending on the distance relative to the bottom current core. Trace fossils are
already known to be a useful tool for studying of contouritic deposits and are even used as criterion
for differentiating associated facies (e.g., turbidites, debrites), though not without controversy. We
propose a mechanism by which the distance to the bottom current core exerts tangible influence on
specific macro-benthic tracemaker communities in contourite deposits. This parameter itself reflects
other bottom current features, such as hydrodynamic energy, grain size, nutrient transport, etc.
Ichnological analysis can thus resolve cryptic features of contourite drift depositional settings.The contribution and research by JD was funded through the European Union’s Horizon 2020 research and
innovation programme under the Marie Skłodowska-Curie grant agreement No 792314 (ICON-SE). The
research of FJR-T was funded by project CGL2015-66835-P (Secretaría de Estado de Investigacion, Desarrollo e
Innovacion, Spain), Research Group RNM-178 (Junta de Andalucía), and Scientific Excellence Unit UCE-2016-
05 (Universidad de Granada). AM’s research is funded by the I2C program of the Xunta de Galicia Postdoctoral
programme (ED481B 2016/029-0). The research was conducted as part of “The Drifters Research Group” (RHUL)
and “Ichnology and Palaeoenvironment Research Group” (UGR) programs
School-based physical education programs: evidence-based physical activity interventions for youth in Latin America
This article focuses on results of the systematic review from the Guide for
Useful Interventions for Activity in Latin America project related to
school-based physical education (PE) programs in Latin America. The aims of the
article are to describe five school-based PE programs from Latin America,
discuss implications for effective school-based PE recommendations, propose
approaches for implementing these interventions, and identify gaps in the
research literature related to physical activity promotion in Latin American
youth. Following the US Community Guide systematic review
process, five school-based PE intervention studies with sufficient quality of
design, execution and detail of intervention and outcomes were selected for full
abstraction. One study was conducted in Brazil, two studies were conducted in
Chile and two studies were conducted on the US/Mexico border. While studies
presented assorted outcomes, methods and duration of interventions, there were
consistent positive increases in physical activity levels for all outcomes
measured during PE classes, endurance and active transportation to school in all
three randomized studies. Except for one cohort from one study, the
non-randomized studies showed positive intervention effects for moderate and
vigorous physical activity levels during PE classes. The core elements of these
five interventions included capacity building and staff training (PE specialists
and/or classroom teachers); changes in the PE curricula; provision of equipment
and materials; and adjustment of the interventions to specific target
populations. In order to translate the strong evidence for school-based PE into
practice, systematic attention to policy and implementation issues is required.
(Global Health Promotion, 2010; 17(2): pp. 05–15
Genomic and biological characterization of chiltepin yellow mosaic virus, a new tymovirus infecting Capsicum annuum var. aviculare in Mexico.
The characterization of viruses infecting wild plants is a key step towards understanding the ecology of plant viruses. In this work, the complete genomic nucleotide sequence of a new tymovirus species infecting chiltepin, the wild ancestor of Capsicum annuum pepper crops, in Mexico was determined, and its host range has been explored. The genome of 6,517 nucleotides has the three open reading frames described for tymoviruses, putatively encoding an RNA-dependent RNA polymerase, a movement protein and a coat protein. The 5′ and 3′ untranslated regions have structures with typical signatures of the tymoviruses. Phylogenetic analyses revealed that this new virus is closely related to the other tymoviruses isolated from solanaceous plants. Its host range is mainly limited to solanaceous species, which notably include cultivated Capsicum species. In the latter, infection resulted in a severe reduction of growth, indicating the potential of this virus to be a significant crop pathogen. The name of chiltepin yellow mosaic virus (ChiYMV) is proposed for this new tymovirus
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