1,348 research outputs found
Disparate compound eyes of Cambrian radiodonts reveal their developmental growth mode and diverse visual ecology
Radiodonts are nektonic stem-group euarthropods that played various trophic roles in Paleozoic marine ecosystems, but information on their vision is limited. Optical details exist only in one species from the Cambrian Emu Bay Shale of Australia, here assigned to Anomalocaris aff. canadensis. We identify another type of radiodont compound eye from this deposit, belonging to ‘Anomalocaris’ briggsi. This ≤4-cm sessile eye has >13,000 lenses and a dorsally oriented acute zone. In both taxa, lenses were added marginally and increased in size and number throughout development, as in many crown-group euarthropods. Both species’ eyes conform to their inferred lifestyles: The macrophagous predator A. aff. canadensis has acute stalked eyes (>24,000 lenses each) adapted for hunting in well-lit waters, whereas the suspension-feeding ‘A.’ briggsi could detect plankton in dim down-welling light. Radiodont eyes further demonstrate the group’s anatomical and ecological diversity and reinforce the crucial role of vision in early animal ecosystems.Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC). This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial license, which permits use, distribution, and reproduction in any medium, so long as the resultant use is not for commercial advantage and provided the original work is properly cited
Nuevos restos de organismos de cuerpo blando en la Formación San José (Ordovícico) de la Cordillera Oriental peruana
El registro fósil de organismos de cuerpo blando o con caparazón no biomineralizado se halla prácticamente restringido a los llamados yacimientos de conservación excepcional (Konservat-Lagerstätten), raros en el Fanerozoico (Muscente et al., 2017). En el Paleozoico Inferior, los ejemplos más notables de conservación excepcional se dan en el Cámbrico (biotas de Burgess Shale, Chenjiang, Emu Bay Shale, Sirius Passet, etc.), siendo muy raros, salvo notorias excepciones, en el Ordovícico (Martin et al., 2016b, con referencias). En Sudamérica, los primeros anuncios del descubrimiento de restos de paleoscolécidos (gusanos priapúlidos ancestrales) se deben a García-Bellido & Aceñolaza (2005), en el Cámbrico argentino, y a Gutiérrez-Marco & Chacaltana (2006), en el Ordovícico peruano. Los representantes de ese grupo fósil son bastante comunes en los yacimientos de tipo «Burgess Shale» en todo el mundo. No obstante, los primeros restos de artrópodos con el mismo estilo de preservación excepcional se encontraron poco después en materiales del Furongiense de Argentina (Apankura: Vaccari et al., 2004) y del Tremadociense del mismo país (Mimetaster: Aris et al., 2017). En cuanto a los cuerpos vermiformes antes citados, se trataba en ambos casos de ejemplares únicos, asignados más tarde a los géneros Palaeoscolex (García-Bellido & Aceñolaza, 2011; revisado como gen. indet. en García-Bellido et al., 2013) y Juninscolex (García-Bellido et al., 2008), respectivamente. Con todo, los fósiles articulados de paleoscolécidos siguen siendo relativamente raros en el Ordovícico, y las síntesis mundiales más recientes (Muir et al., 2014; Wang et al., 2014) siguen citando a Juninscolex ingemmetianum García-Bellido, Gutiérrez-Marco & Chacaltana como el único escleritoma de paleoscolécido reportado en Sudamérica. De ahí el interés potencial de cualquier nuevo hallazgo para el registro del grupo en el Ordovícico. También a escala del continente de Gondwana, donde últimamente se han incorporado datos importantes de paleoscolécidos procedentes del Ordovícico Inferior y Superior de Marruecos (Gutiérrez-Marco & García-Bellido, 2015; Martin et al., 2016a). En el presente trabajo introducimos dos nuevas localidades con fósiles de cuerpo blando en el Ordovícico peruano. Ambas radican en la Formación San José de la Cordillera Oriental, en sendas secciones de los departamentos del Cusco y Puno
Modeling discards in Trawling Mediterranean Northern Alboran Sea Fishery
Target and Bycatch species metrics estimated from fishery-dependent data were explored to assess their use in governance of habitat conservation in respect to fisheries. Fishing data collected by onboard observers in otter-trawl boats between 2011 and 2012 at monthly sampling frequency in the Alboran Sea (Western Mediterranean) were used to build maps of sensitivity to fishing stress. Maps were drawn by means kriging interpolation techniques of biomass and abundance (Catch Per Unit of Effort, CPUE) in kilogram and number per fishing hour of blue whiting (Micromesistius poutassou), European hake (Merluccius merluccius), and red mullets (Mullus barbatus and Mullus surmuletus) target species, seabreams (Pagellus acarne, Pagellus bogaraveo, and Pagellus erythrinus), and mackerels (Trachurus mediterraneus, Trachurus trachurus, and Trachurus picturatus) bycatch species and Bogue (Boops boops) bycatch discarded species. Modelling discards by means Generalised Additive Models (GAMs) use environmental (sea surface temperature and chlorophyll-a from satellite data and NAO climatic index); spatial (latitude, longitude, depth and port) and temporal (season, haul duration, moon phase), as well as technical (boat length and power) explanatory variables. The main causes of discards, for both target and bycatch species, are associated to the seasonality of the recruitment and the changes on the spatial distribution of habitat preferences along their ontogeny. Environmental variables did not reveal significant effects, showing that operational oceanography standard products must be not enough to assess discards, and therefore products providing information on specific ecological processes to discards must be designed with this purpose. In Bycatch species, such as sea breams, mackerels and bogue, discards were also highly dependent of the port and boat (fleet/boat strategies, power, etc, and market preferences). The higher discards corresponded to these bycatch pelagic or bentho-pelagic species. Keywords: Discards, Otter-trawl fisheries, fishery conservation, operational oceanography, spatial modelin
Comprehensive approach to people with type 2 diabetes. Diabetes Knowledge Area of the Spanish Society of Endocrinology and Nutrition
[ES] Objetivo: Proporcionar recomendaciones prácticas para el abordaje integral de las personas con diabetes tipo 2 según la medicina basada en la evidencia. Participantes: Miembros del Área de Conocimiento de Diabetes de la Sociedad Española de Endocrinología y Nutrición. Métodos: Las recomendaciones se formularon según los grados de evidencia de los Standards of Medical Care in Diabetes—2022. Tras la revisión de la evidencia disponible y la formulación de recomendaciones por los autores de cada apartado, se desarrollaron varias rondas de comentarios con incorporación de las aportaciones y votación de los puntos controvertidos. Por último, el documento final se remitió al resto de los miembros del área para revisión e incorporación de aportaciones, para, finalmente, realizar el mismo proceso con los miembros de la Junta Directiva de la Sociedad Española de Endocrinología y Nutrición. Conclusiones: El documento establece unas recomendaciones prácticas basadas en la última evidencia disponible para el manejo de las personas con diabetes tipo 2.[EN] Objective. To provide practical recommendations for the comprehensive approach of people with type 2 diabetes according to evidence-based medicine.
Participants. Members of the Diabetes Knowledge Area of the Spanish Society of Endocrinology and Nutrition.
Methods. The recommendations were formulated according to the degrees of evidence of the Standards of Medical Care in Diabetes—2022. After reviewing the available evidence and formulating recommendations by the authors of each section, several rounds of comments were developed incorporating the contributions and voting on controversial points. Finally, the final document was sent to the rest of the members of the area for review and incorporation of contributions, to finally carry out the same process with the members of the Spanish Society of Endocrinology and Nutrition Board of Directors.
Conclusions. The document establishes practical recommendations based on the latest available evidence for the management of people with type 2 diabetes.Peer reviewe
Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory
The Auger Engineering Radio Array (AERA) is part of the Pierre Auger
Observatory and is used to detect the radio emission of cosmic-ray air showers.
These observations are compared to the data of the surface detector stations of
the Observatory, which provide well-calibrated information on the cosmic-ray
energies and arrival directions. The response of the radio stations in the 30
to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of
the incoming electric field. For the latter, the energy deposit per area is
determined from the radio pulses at each observer position and is interpolated
using a two-dimensional function that takes into account signal asymmetries due
to interference between the geomagnetic and charge-excess emission components.
The spatial integral over the signal distribution gives a direct measurement of
the energy transferred from the primary cosmic ray into radio emission in the
AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air
shower arriving perpendicularly to the geomagnetic field. This radiation energy
-- corrected for geometrical effects -- is used as a cosmic-ray energy
estimator. Performing an absolute energy calibration against the
surface-detector information, we observe that this radio-energy estimator
scales quadratically with the cosmic-ray energy as expected for coherent
emission. We find an energy resolution of the radio reconstruction of 22% for
the data set and 17% for a high-quality subset containing only events with at
least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO
Planck 2013 results. XXII. Constraints on inflation
We analyse the implications of the Planck data for cosmic inflation. The Planck nominal mission temperature anisotropy measurements, combined with the WMAP large-angle polarization, constrain the scalar spectral index to be ns = 0:9603 _ 0:0073, ruling out exact scale invariance at over 5_: Planck establishes an upper bound on the tensor-to-scalar ratio of r < 0:11 (95% CL). The Planck data thus shrink the space of allowed standard inflationary models, preferring potentials with V00 < 0. Exponential potential models, the simplest hybrid inflationary models, and monomial potential models of degree n _ 2 do not provide a good fit to the data. Planck does not find statistically significant running of the scalar spectral index, obtaining dns=dln k = 0:0134 _ 0:0090. We verify these conclusions through a numerical analysis, which makes no slowroll approximation, and carry out a Bayesian parameter estimation and model-selection analysis for a number of inflationary models including monomial, natural, and hilltop potentials. For each model, we present the Planck constraints on the parameters of the potential and explore several possibilities for the post-inflationary entropy generation epoch, thus obtaining nontrivial data-driven constraints. We also present a direct reconstruction of the observable range of the inflaton potential. Unless a quartic term is allowed in the potential, we find results consistent with second-order slow-roll predictions. We also investigate whether the primordial power spectrum contains any features. We find that models with a parameterized oscillatory feature improve the fit by __2 e_ _ 10; however, Bayesian evidence does not prefer these models. We constrain several single-field inflation models with generalized Lagrangians by combining power spectrum data with Planck bounds on fNL. Planck constrains with unprecedented accuracy the amplitude and possible correlation (with the adiabatic mode) of non-decaying isocurvature fluctuations. The fractional primordial contributions of cold dark matter (CDM) isocurvature modes of the types expected in the curvaton and axion scenarios have upper bounds of 0.25% and 3.9% (95% CL), respectively. In models with arbitrarily correlated CDM or neutrino isocurvature modes, an anticorrelated isocurvature component can improve the _2 e_ by approximately 4 as a result of slightly lowering the theoretical prediction for the ` <_ 40 multipoles relative to the higher multipoles. Nonetheless, the data are consistent with adiabatic initial conditions
Measurement of the cosmic ray spectrum above eV using inclined events detected with the Pierre Auger Observatory
A measurement of the cosmic-ray spectrum for energies exceeding
eV is presented, which is based on the analysis of showers
with zenith angles greater than detected with the Pierre Auger
Observatory between 1 January 2004 and 31 December 2013. The measured spectrum
confirms a flux suppression at the highest energies. Above
eV, the "ankle", the flux can be described by a power law with
index followed by
a smooth suppression region. For the energy () at which the
spectral flux has fallen to one-half of its extrapolated value in the absence
of suppression, we find
eV.Comment: Replaced with published version. Added journal reference and DO
Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy
We measure the energy emitted by extensive air showers in the form of radio
emission in the frequency range from 30 to 80 MHz. Exploiting the accurate
energy scale of the Pierre Auger Observatory, we obtain a radiation energy of
15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV
arriving perpendicularly to a geomagnetic field of 0.24 G, scaling
quadratically with the cosmic-ray energy. A comparison with predictions from
state-of-the-art first-principle calculations shows agreement with our
measurement. The radiation energy provides direct access to the calorimetric
energy in the electromagnetic cascade of extensive air showers. Comparison with
our result thus allows the direct calibration of any cosmic-ray radio detector
against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI.
Supplemental material in the ancillary file
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