1,586 research outputs found
High and Far: Biases in the Location of Protected Areas
BACKGROUND: About an eighth of the earth's land surface is in protected areas (hereafter "PAs"), most created during the 20(th) century. Natural landscapes are critical for species persistence and PAs can play a major role in conservation and in climate policy. Such contributions may be harder than expected to implement if new PAs are constrained to the same kinds of locations that PAs currently occupy. METHODOLOGY/PRINCIPAL FINDINGS: Quantitatively extending the perception that PAs occupy "rock and ice", we show that across 147 nations PA networks are biased towards places that are unlikely to face land conversion pressures even in the absence of protection. We test each country's PA network for bias in elevation, slope, distances to roads and cities, and suitability for agriculture. Further, within each country's set of PAs, we also ask if the level of protection is biased in these ways. We find that the significant majority of national PA networks are biased to higher elevations, steeper slopes and greater distances to roads and cities. Also, within a country, PAs with higher protection status are more biased than are the PAs with lower protection statuses. CONCLUSIONS/SIGNIFICANCE: In sum, PAs are biased towards where they can least prevent land conversion (even if they offer perfect protection). These globally comprehensive results extend findings from nation-level analyses. They imply that siting rules such as the Convention on Biological Diversity's 2010 Target [to protect 10% of all ecoregions] might raise PA impacts if applied at the country level. In light of the potential for global carbon-based payments for avoided deforestation or REDD, these results suggest that attention to threat could improve outcomes from the creation and management of PAs
Solar cell research, phase 2 Semiannual report
Radiation effects on properties of lithium solar cell
Initial Results of DC Electric Fields, Associated Plasma Drifts, Magnetic Fields, and Plasma Waves Observed on the C/NOFS Satellite
Initial results are presented from the Vector Electric Field Investigation (VEFI) on the Air Force Communication/Navigation Outage Forecasting System (C/NOFS) satellite, a mission designed to understand, model, and forecast the presence of equatorial ionospheric irregularities. The VEFI instrument includes a vector DC electric field detector, a fixed-bias Langmuir probe operating in the ion saturation regime, a flux gate magnetometer, an optical lightning detector, and associated electronics including a burst memory. Compared to data obtained during more active solar conditions, the ambient DC electric fields and their associated E x B drifts are variable and somewhat weak, typically < 1 mV/m. Although average drift directions show similarities to those previously reported, eastward/outward during day and westward/downward at night, this pattern varies significantly with longitude and is not always present. Daytime vertical drifts near the magnetic equator are largest after sunrise, with smaller average velocities after noon. Little or no pre-reversal enhancement in the vertical drift near sunset is observed, attributable to the solar minimum conditions creating a much reduced neutral dynamo at the satellite altitude. The nighttime ionosphere is characterized by larger amplitude, structured electric fields, even where the plasma density appears nearly quiescent. Data from successive orbits reveal that the vertical drifts and plasma density are both clearly organized with longitude. The spread-F density depletions and corresponding electric fields that have been detected thus far have displayed a preponderance to appear between midnight and dawn. Associated with the narrow plasma depletions that are detected are broad spectra of electric field and plasma density irregularities for which a full vector set of measurements is available for detailed study. Finally, the data set includes a wide range of ELF/VLF/HF oscillations corresponding to a variety of plasma waves, in particular banded ELF hiss, whistlers, and lower hybrid wave turbulence triggered by lightning-induced sferics. The VEFI data represents a new set of measurements that are germane to numerous fundamental aspects of the electrodynamics and irregularities inherent to the Earth's low latitude ionosphere
Microscopic origin of the mobility enhancement at a spinel/perovskite oxide heterointerface revealed by photoemission spectroscopy
The spinel/perovskite heterointerface -AlO/SrTiO hosts a
two-dimensional electron system (2DES) with electron mobilities exceeding those
in its all-perovskite counterpart LaAlO/SrTiO by more than an order of
magnitude despite the abundance of oxygen vacancies which act as electron
donors as well as scattering sites. By means of resonant soft x-ray
photoemission spectroscopy and \textit{ab initio} calculations we reveal the
presence of a sharply localized type of oxygen vacancies at the very interface
due to the local breaking of the perovskite symmetry. We explain the
extraordinarily high mobilities by reduced scattering resulting from the
preferential formation of interfacial oxygen vacancies and spatial separation
of the resulting 2DES in deeper SrTiO layers. Our findings comply with
transport studies and pave the way towards defect engineering at interfaces of
oxides with different crystal structures.Comment: Accepted as Rapid Communications in Physical Review
Building Fuzzy Elevation Maps from a Ground-based 3D Laser Scan for Outdoor Mobile Robots
Mandow, A; Cantador, T.J.; Reina, A.J.; MartÃnez, J.L.; Morales, J.; GarcÃa-Cerezo, A. "Building Fuzzy Elevation Maps from a Ground-based 3D Laser Scan for Outdoor Mobile Robots," Robot2015: Second Iberian Robotics Conference, Advances in Robotics, (2016) Advances in Intelligent Systems and Computing, vol. 418. This is a self-archiving copy of the author’s accepted manuscript. The final publication is available at Springer via
http://link.springer.com/book/10.1007/978-3-319-27149-1.The paper addresses terrain modeling for mobile robots with fuzzy elevation maps by improving computational
speed and performance over previous work on fuzzy terrain identification from a three-dimensional (3D) scan. To this end,
spherical sub-sampling of the raw scan is proposed to select training data that does not filter out salient obstacles. Besides,
rule structure is systematically defined by considering triangular sets with an unevenly distributed standard fuzzy partition
and zero order Sugeno-type consequents. This structure, which favors a faster training time and reduces the number of rule
parameters, also serves to compute a fuzzy reliability mask for the continuous fuzzy surface. The paper offers a case study
using a Hokuyo-based 3D rangefinder to model terrain with and without outstanding obstacles. Performance regarding error
and model size is compared favorably with respect to a solution that uses quadric-based surface simplification (QSlim).This work was partially supported by the Spanish CICYT project DPI 2011-22443, the Andalusian project PE-2010 TEP-6101, and Universidad de Málaga-AndalucÃa Tech
Electric field measurements of DC and long wavelength structures associated with sporadic-<i>E</i> layers and QP radar echoes
Electric field and plasma density data gathered on a sounding rocket launched from Uchinoura Space Center, Japan, reveal a complex electrodynamics associated with sporadic-<i>E</i> layers and simultaneous observations of quasi-periodic radar echoes. The electrodynamics are characterized by spatial and temporal variations that differed considerably between the rocket's upleg and downleg traversals of the lower ionosphere. Within the main sporadic-<i>E</i> layer (95–110 km) on the upleg, the electric fields were variable, with amplitudes of 2–4 mV/m that changed considerably within altitude intervals of 1–3 km. The identification of polarization electric fields coinciding with plasma density enhancements and/or depletions is not readily apparent. Within this region on the downleg, however, the direction of the electric field revealed a marked change that coincided precisely with the peak of a single, narrow sporadic-<i>E</i> plasma density layer near 102.5 km. This shear was presumably associated with the neutral wind shear responsible for the layer formation. The electric field data above the sporadic-<i>E</i> layer on the upleg, from 110 km to the rocket apogee of 152 km, revealed a continuous train of distinct, large scale, quasi-periodic structures with wavelengths of 10–15 km and wavevectors oriented between the NE-SW quadrants. The electric field structures had typical amplitudes of 3–5 mV/m with one excursion to 9 mV/m, and in a very general sense, were associated with perturbations in the plasma density. The electric field waveforms showed evidence for steepening and/or convergence effects and presumably had mapped upwards along the magnetic field from the sporadic-<i>E</i> region below. Candidate mechanisms to explain the origin of these structures include the Kelvin-Helmholtz instability and the <i>E<sub>s</sub></i>-layer instability. In both cases, the same shear that formed the sporadic-<i>E</i> layer would provide the energy to generate the km-scale structures. Other possibilities include gravity waves or a combination of these processes. The data suggest that these structures were associated with the lower altitude density striations that were the seat of the QP radar echoes observed simultaneously. They also appear to have been associated with the mechanism responsible for a well-defined pattern of "whorls" in the neutral wind data that were revealed in a chemical trail released by a second sounding rocket launched 15min later. Short scale (<100 m) electric field irregularities were also observed and were strongest in the sporadic-<i>E</i> region below 110km. The irregularities were organized into 2–3 layers on the upleg, where the plasma density also displayed multiple layers, yet were confined to a single layer on the downleg where the plasma density showed a single, well-defined sporadic-<i>E</i> peak. The linear gradient drift instability involving the DC electric field and the vertical plasma gradient is shown to be incapable of driving the observed waves on the upleg, but may have contributed to the growth of short scale waves on the topside of the narrow unstable density gradient observed on the downleg. The data suggest that other sources of free energy may have been important factors for the growth of the short scale irregularities.<p> <b>Keywords.</b> Ionosphere (Mid-latitude ionosphere; Electric fields and currents; Ionospheric irregularities
Model-based engineering of widgets, user applications and servers compliant with ARINC 661 specification
International audienceThe purpose of ARINC 661 specification [1] is to define interfaces to a Cockpit Display System (CDS) used in any types of aircraft installations. ARINC 661 provides precise information for communication protocol between application (called User Applications) and user interface components (called widgets) as well as precise information about the widgets themselves. However, in ARINC 661, no information is given about the behaviour of these widgets and about the behaviour of an application made up of a set of such widgets. This paper presents the results of the application of a formal description technique to the various elements of ARINC 661 specification within an industrial project. This formal description technique called Interactive Cooperative Objects defines in a precise and non-ambiguous way all the elements of ARINC 661 specification. The application of the formal description techniques is shown on an interactive application called MPIA (Multi Purpose Interactive Application). Within this application, we present how ICO are used for describing interactive widgets, User Applications and User Interface servers (in charge of interaction techniques). The emphasis is put on the model-based management of the feel of the applications allowing rapid prototyping of the external presentation and the interaction techniques. Lastly, we present the CASE (Computer Aided Software Engineering) tool supporting the formal description technique and its new extensions in order to deal with large scale applications as the ones targeted at by ARINC 661 specification
Anxiety, depression, and comorbid anxiety and depression: Risk factors and outcome over two years
Background: This study aimed to determine: (1) the prevalence of depression, anxiety, and depression associated with anxiety (DA); (2) the risk factor profile of depression, anxiety, and DA; (3) the course of depression, anxiety, and DA over 24 months. Methods: Two-year longitudinal study of 20,036 adults aged 60+ years. We used the Patient Health Questionnaire and the Hospital Anxiety and Depression Scale anxiety subscale to establish the presence of depression and anxiety, and standard procedures to collect demographic, lifestyle, psychosocial, and clinical data. Results: The prevalence of anxiety, depression, and DA was 4.7%, 1.4%, and 1.8%. About 57% of depression cases showed evidence of comorbid anxiety, while only 28% of those with clinically significant anxiety had concurrent depression. There was not only an overlap in the distribution of risk factors in these diagnostic groups but also differences. We found that 31%, 23%, and 35% of older adults with anxiety, depression, and DA showed persistence of symptoms after two years. Repeated anxiety was more common in women and repeated depression in men. Socioeconomic stressors were common in repeated DA. Conclusions: Clinically significant anxiety and depression are distinct conditions that frequently coexist in later life; when they appear together, older adults endure a more chronic course of illness
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