10,767 research outputs found
Heathland creation on improved grassland using sulphur: is there a conflict between optimal application rates for plant and animal communities?
We examined the effectiveness of using elemental sulphur (a soil acidifier) as a method for creating heathland on improved pasture. We determined i) optimal rate of sulphur application to control mesotrophic grasses ii) if invertebrates avoid areas of sulphur application. Results indicated that optimal sulphur application attracted invertebrates
Whose Data Is It Anyway? Lessons in Data Management and Sharing from Resurrecting and Repurposing Lidar Data for Archaeology Research in Honduras
As a response to Hurricane Mitch and the resulting widespread loss of life and destruction of Honduran infrastructure in 1998, the United States Geological Survey (USGS) conducted the first wide-area airborne lidar topographic mapping project in Central America. The survey was executed by the Bureau of Economic Geology at the University of Texas at Austin (BEG) in 2000, and it was intended to cover 240 square kilometers distributed among 15 flood-prone communities throughout Honduras. The original data processing produced basic digital elevation models at 1.5-meter grid spacing which were used as inputs for hydrological modeling. The USGS published the results in a series of technical reports in 2002. The authors became interested in this dataset in 2013 while searching for geospatial data that would provide additional context and comparative references for an archaeological lidar project conducted in 2012 in the Honduran Mosquitia. After multiple requests to representatives from the USGS and BEG, we found various types of processed data in personal and institutional archives, culminating in the identification of 8-mm magnetic tapes that contained the original point clouds. Point clouds for the 15 communities plus a test area centered on the Maya site of Copán were recovered from the tapes (16 areas totaling 700 km2). These point clouds have been reprocessed by the authors using contemporary software and methods into higher resolution and fidelity products. Within these new products, we have identified and mapped multiple archaeological sites in proximity to modern cities, many of which are not part of the official Honduran site registry. Besides improving our understanding of ancient Honduras, our experiences dealing with issues of data management and access, ethics, and international collaboration have been informative. This paper summarizes our experiences in the hope that they will contribute to the discussion and development of best practices for handling geospatial datasets of archaeological value
The exotic weevil Stenopelmus rufinasus Gyllenhal, 1835 (Coleoptera: Curculionidae) across a "host-free" pond network
The presence of the exotic weevil Stenopelmus rufinasus (Coleoptera: Curculionidae) is closely related to the occurrence of
the exotic red water fern, Azolla filiculoides. In this paper, we present the first records of S. rufinasus in Doñana National
Park (SW Spain), based on sampling of macroinvertebrates in 91 temporary ponds, including monthly samples of 22 ponds,
during two successive years (2005-2007). The exotic weevil was present in 21% of the sampled ponds where the host plant, A.
filiculiodes, was not detectable. Because A. filiculoides can reach high densities in an adjacent area of marsh, we suggest that
the occurrence of the exotic weevil in these ponds is a consequence of dispersal from nearby marshes. Our study demonstrates
that S. rufinasus adults can occur at relatively high densities in ponds where the host plant is not present, suggesting that such
apparently “host-free” sites may act as stepping stones for the spread of this speciesLa presencia de la especie de gorgojo exótico Stenopelmus rufinasus (Coleoptera: Curculionidae) está íntimamente rela-
cionada con la planta acuática exótica Azolla filiculoides. En este estudio se registró por primera vez la presencia de S.
rufinasus en el Parque Nacional de Doñana (SO España) tras realizar un muestreo de macroinvertebrados en 91 lagunas
que incluye muestreos mensuales de 22 de las mismas durante dos años consecutivos (2005-2007). El gorgojo exótico estuvo
presente en el 21% de las lagunas muestreadas a pesar de que su supuesto hospedador, A. filiculiodes, no fue detectado.
Dado que A. filiculiodes puede alcanzar grandes densidades en la marisma adyacente, sugerimos que la presencia del gor-
gojo exótico en las lagunas temporales se debe a su dispersión desde la marisma. Este estudio demuestra que individuos
adultos de S. rufinasus pueden aparecer con densidades relativamente altas en lagunas donde su hospedador potencial no
está presente, lo que sugiere que estos sitios libres de hospedador podrían actuar como zonas de paso para la dispersión de
la especiePeer reviewe
Crystal and magnetic structure of the oxypnictide superconductor LaO(1-x)FxFeAs: evidence for magnetoelastic coupling
High-resolution and high-flux neutron as well as X-ray powder-diffraction
experiments were performed on the oxypnictide series LaO(1-x)FxFeAs with
0<x<0.15 in order to study the crystal and magnetic structure. The magnetic
symmetry of the undoped compound corresponds to those reported for ReOFeAs
(with Re a rare earth) and for AFe2As2 (A=Ba, Sr) materials. We find an ordered
magnetic moment of 0.63(1)muB at 2 K in LaOFeAs, which is significantly larger
than the values previously reported for this compound. A sizable ordered
magnetic moment is observed up to a F-doping of 4.5% whereas there is no
magnetic order for a sample with a F concentration of x=0.06. In the undoped
sample, several interatomic distances and FeAs4 tetrahedra angles exhibit
pronounced anomalies connected with the broad structural transition and with
the onset of magnetism supporting the idea of strong magneto-elastic coupling
in this material.Comment: 8 pages, 7 figures, regular articl
Permo-Carboniferous magmatism in the core of Pangaea (Southern Pyreness): a possible linkange between the Variscan and Cimmerian cycles?
In southern Europe and the western Mediterranean, Permo-Carboniferous magmatism is well represented in areas
of Iberia, the Alps, Sardinia and the Balkan Peninsula. In Iberia, the magmatism that has been related to the
Variscan orogeny is associated with syn-orogenic events at ca. 350-315 Ma and post-orogenic at ca. 310-295
Ma. In the southern Pyrenees there is Permo-Carboniferous sedimentary basins with a significant volume of
rhyolitic ignimbrites and andesitic flows. The Erill Castell-Estac, Cadí and Castellar de n’Hug basins are spatially
associated with the Boí, Montellá and Vielha granites and the Cardet dacitic dykes emplaced in Variscan basement
rocks. U-Pb SHRIMP dating of zircons extracted from these granites, an andesitic flow, a dacitic dyke and six
ignimbrites, revealed that magmatism was active from ca. 304 Ma to ca. 266 Ma. The scattering of zircon ages
in each sample shows that the history of melt crystallization was prolonged and complex. The reported ages of
the magmatic activity for the Southern Pyrenees in the range ca. 304-283 Ma (this study) fit in well with the
time interval of magmatism related to the early North-dipping subduction of the Western Paleotethys Ocean, the
subsequent development of Iberian orocline (Variscan cycle), and the large-scale bending and blocking of the
Paleotethys Ocean subduction at East of Iberia.In paleogeographic reconstructions of the Permo-Carboniferous, Iberia is located in the core of Pangaea to the
east of the probable Rheic Ocean suture and near the western end of the subduction zone of the Paleotethys
Ocean. The emplacement in Iberia of granites with ca. 310-278 Ma age occurred after the collision of Laurussia
and Gondwana, when the subduction of the Rheic Ocean was inactive. From a Variscan-cycle perspective, the
Permo-Carboniferous magmatism of the Pyrenees has been considered as post-orogenic. However, global paleogeographic
reconstructions put Iberia in between the Rheic Ocean suture and the still active subduction zone of the
Western Paleotethys Ocean. Therefore, the Permo-Carboniferous magmatism of Iberia, from a Cimmerian-cycle
perspective, may have accompanied the closing of the Paleotethys Ocean. During this stage of the evolution of
Pangaea, the east of Iberia was geologically affected by the active subduction zone of the Paleotethys Ocean. The
period ca. 310-285 Ma is marked by the development of an orocline that extends from Iberia to Armorica. The
northwards subduction of the western corner of Paleotethys probably caused orocline formation and consequent
large-scale bending and blocking of Paleotethys subduction immediately east of Iberia. The Permo-Carboniferous
magmatism of Iberia, coeval with this tectonic evolution, shows a mixed imprint of subduction and delamination
geochemical signatures. Although this may seem controversial, in our view the magmatic activity preserved in
the Southern Pyrenees could provide the missing link between the development of the Iberian orocline and the
continued subduction of easternmost segments of the Paleotethys Ocean (Cimmerian cycle) during the evolution
of Pangaea
Interactive Neural Resonators
In this work, we propose a method for the controllable synthesis of real-time contact sounds using neural resonators. Previous works have used physically inspired statistical methods and physical modelling for object materials and excitation signals. Our method incorporates differentiable second-order resonators and estimates their coefficients using a neural network that is conditioned on physical parameters. This allows for interactive dynamic control and the generation of novel sounds in an intuitive manner. We demonstrate the practical implementation of our method and explore its potential creative applications
Cambrian ensialic rift-related magmatism in the Ossa-Morena Zone
The Late Ediacaran (c. 560–550 Ma) Série Negra sediments of the Évora–Aracena metamorphic belt, Ossa-Morena Zone, SW Iberian Massif,
preserve a record of the erosion of an Avalonian–Cadomian magmatic arc and subsequent related turbiditic sedimentation. Detrital zircon from the
Série Negra is characterized by predominantly Ediacaran and Cryogenian ages, with few Paleoproterozoic and Archean cores, and a marked lack
of Grenvillian ages. These features, when combined with the metasediments' enrichment in LREE (La/Yb=14), negative Eu-anomalies, low
147Sm/144Nd values (0.121) and negative εNd550=−5.5, indicate that the protolith Série Negra sediments were derived from a continental
magmatic arc.
A period of Late Cadomian (ca. 560–540 Ma) tectonism was followed by an extended episode of widespread bimodal magmatism related to
Cambrian (ca. 540–500 Ma) rifting. This tectonic inversion is expressed in the geological record by a regional Early Cambrian unconformity.
SHRIMP zircon U–Th–Pb ages from four felsic orthogneisses from the Évora Massif record Cambrian (527±10 Ma, 522±5 Ma, 517±6 Ma
and 505±5 Ma) crystallization ages for their igneous protoliths. This confirms the existence of widespread Lower Paleozoic igneous activity in the
Ossa-Morena Zone: (i) a Lower Cambrian (ca. 535–515 Ma) igneous–felsic dominated–sedimentary complex (with calc-alkaline signature and
associated carbonate and siliciclastic deposition), and (ii) a Middle Cambrian–?Ordovician (ca. 515–490 Ma) igneous–bimodal–sedimentary
complex (with calc-alkaline and tholeiitic signatures and associated dominant siliciclastic deposition, but also carbonate sediments).
The Cambrian felsic magmatism was characterized by negative Eu-anomalies, (La/Lu)N=0.8–11, 147Sm/144Nd=0.1289–0.1447 and εNd500
ranging from −1.5 to −0.8. A tendency towards peraluminous compositions suggests late fractionation, low degrees of partial melting, or the
mixing of crustal and mantle-derived material in the magma source region. Some felsic rocks possibly represent the last residual melts of hightemperature,
zircon-undersaturated mafic magmas later affected by crustal contamination, while others indicate partial melting of crustal
metasediments variably contaminated by basaltic liquids.
The transition from early felsic dominated to later more mafic magmatism suggests the gradual opening of the system to tholeiitic N–E-MORB
products (ThN/TaNb1.0). The as yet undated (Cambrian–?Ordovician) E-MORB amphibolites have 147Sm/144Nd=0.1478–0.1797 and εNd500
values ranging from +6.4 to +7.3, while the N-MORB amphibolites have 147Sm/144Nd=0.1818–0.1979 and εNd500 values of +5.8 and +7.0,
reaching a maximum of +9.1. In contrast, other amphibolites have a negative Ta-anomaly (1.35bThN/TaNb2.41) reminiscent of lavas from
“orogenic” settings or alternatively, typical of crustally-contaminated within-plate magmas. These “VAB-like” amphibolites have 147Sm/144Nd
values ranging from 0.1639 to 0.1946 and εNd500 values of +3.5 to +5.2, suggesting derivation by crustal assimilation processes. The subalkaline
igneous precursors of the amphibolites were most likely generated in a rift setting by asthenospheric upwelling. These results strengthen the proposed geodynamic scenarios for the SW Iberian Massif by which Cadomian accretion gave rise to an ensialic
rift that developed into a proto-oceanic basin and incipient spreading (opening of the Rheic Ocean?). A similar transition from a convergent to a
divergent plate boundary during the Ediacaran to Cambrian–?Ordovician has also been reported in other segments of the northern Gondwana
margin
The Brazilian Network for HIV-1 Genotyping External Quality Control Assurance Programme
The Brazilian network for genotyping is composed of 21 laboratories that perform and analyze genotyping tests for all HIV-infected patients within the public system, performing approximately 25,000 tests per year. We assessed the interlaboratory and intralaboratory reproducibility of genotyping systems by creating and implementing a local external quality control evaluation. Plasma samples from HIV-1-infected individuals (with low and intermediate viral loads) or RNA viral constructs with specific mutations were used. This evaluation included analyses of sensitivity and specificity of the tests based on qualitative and quantitative criteria, which scored laboratory performance on a 100-point system. Five evaluations were performed from 2003 to 2008, with 64% of laboratories scoring over 80 points in 2003, 81% doing so in 2005, 56% in 2006, 91% in 2007, and 90% in 2008 (Kruskal-Wallis, p = 0.003). Increased performance was aided by retraining laboratories that had specific deficiencies. The results emphasize the importance of investing in laboratory training and interpretation of DNA sequencing results, especially in developing countries where public (or scarce) resources are used to manage the AIDS epidemic
Conventional Cervical Exercises Compared with a Mixed-Reality-Based Game in Asymptomatic Subjects: An Exploratory Crossover Pilot Study.
Mixed reality presents itself as a potential technological tool for the management of people
with musculoskeletal disorders, without having as many adverse side effects as immersive virtual
reality. The objective of this study was to explore the possibilities of a mixed-reality game, performing
task-oriented cervical exercises compared to conventional therapeutic exercises in sensorimotor
outcome measures in asymptomatic subjects. A randomized crossover pilot study was performed
with two intervention groups: a mixed-reality group (MRG) and a conventional exercise group (CEG).
The cervical joint position error test (CJPET) and deep cervical flexor endurance test (DCFET) were
measured as sensorimotor outcomes. Statistically significant differences were found in the pre–post
comparison in the DCFET for both groups (MRG: t = �����3.87, p < 0.01; CEG: t = �����4.01, p < 0.01)
and in the extension of the CJPET for the MRG (t = 3.50, p < 0.01). The rest of the measurements
showed no significant differences comparing both groups pre- and postintervention (p > 0.05). Mixed
reality has apparently the same positive effects as conventional exercises in sensorimotor outcomes
in asymptomatic subjects. These results could help in future studies with mixed virtual reality in the
management of people with musculoskeletal disorders.post-print882 K
Entropy calculation for a toy black hole
In this note we carry out the counting of states for a black hole in loop
quantum gravity, however assuming an equidistant area spectrum. We find that
this toy-model is exactly solvable, and we show that its behavior is very
similar to that of the correct model. Thus this toy-model can be used as a nice
and simplifying `laboratory' for questions about the full theory.Comment: 18 pages, 4 figures. v2: Corrected mistake in bibliography, added
appendix with further result
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