3,241 research outputs found
Internal Structure of Ariebreen, Spitsbergen, from radio-echo sounding data
Ariebreen (77º 01' N, 15º 29' E) is a small valley glacier (ca. 0.36 km2 in August 2007) located at Hornsund, Spitsbergen, Svalbard, ca. 2.5 km to the west of Hornsund Polish Polar Station. Ariebreen, like many other Svalbard glaciers, has experienced a significant recession at least since the 1930s, and most likely since the end of Little Ice Age (LIA) in the early part of the 20th century. Moreover, the thinning rate of western Svalbard glaciers has shown an acceleration during the most recent decades. Ariebreen follows this general retreat pattern, as is shown in another contribution to this workshop (Petlicki et al., 2008). Most investigated glaciers in Hornsund area, in the neighbourhood of Ariebreen, are known to be polythermal (e.g. Hansbreen and Werenskioldbreen, Pälli et al., 2003). It has been suggested (Macheret et al., 1992) that the thinning of polythermal glaciers may result in a switch to cold thermal structure under appropriate conditions. The strong thinning experienced by Ariebreen during the recent decades makes it an ideal candidate to undergo such change. The main aims of this contribution are to understand the internal structure of Ariebreen, in particular, its hydrothermal regime, and to determine whether the glacier is undergoing or has already experienced a transition from polythermal to cold structure. The main tool to accomplish this will be the analysis of radio-echo sounding data
Effect of silver on the phase transition and wettability of titanium oxide films
The effect of silver on the phase transition and microstructure of titanium oxide films grown by pulsed cathodic arc had been investigated by XRD, SEM and Raman spectroscopy. Following successive thermal annealing up to 1000 °C, microstructural analysis of annealed Ag-TiO2 films reveals that the incorporation of Ag nanoparticles strongly affects the transition temperature from the initial metastable amorphous phase to anatase and stable rutile phase. An increase of silver content into TiO2 matrix inhibits the amorphous to anatase phase transition, raising its temperature boundary and, simultaneously reduces the transition temperature to promote rutile structure at lower value of 600 °C. The results are interpreted in terms of the steric effects produced by agglomeration of Ag atoms into larger clusters following annealing which hinders diffusion of Ti and O ions for anatase formation and constrains the volume available for the anatase lattice, thus disrupting its structure to form rutile phase. The effect of silver on the optical and wetting properties of TiO2 was evaluated to demonstrate its improved photocatalytic performance
Spontaneous creation of circularly polarized photons in chiral astrophysical systems
This work establishes a relation between chiral anomalies in curved
spacetimes and the radiative content of the gravitational field. In particular,
we show that a flux of circularly polarized gravitational waves triggers the
spontaneous creation of photons with net circular polarization from the quantum
vacuum. Using waveform catalogues we identify precessing binary black holes as
astrophysical configurations that emit such gravitational radiation, and then
solve the fully non-linear Einstein's equations with numerical relativity to
evaluate the net effect. The quantum amplitude for a merger is comparable to
the Hawking emission rate of the final black hole, and small to be directly
observed. However, the implications for the inspiral of binary neutron stars
could be more prominent, as argued on symmetry grounds.Comment: 7 pages, 3 figure
A Model for Evaluating Soil Vulnerability to Erosion Using Remote Sensing Data and A Fuzzy Logic System
Soil vulnerability is the capacity of one or more of the ecological functions of the soil system to be harmed. It is a complex concept which requires the identification of multiple environmental factors and land management at different temporal and space scales. The employment of geospatial information with good update capabilities could be a satisfactory tool to assess potential soil vulnerability changes in large areas. This chapter presents the application of two land degradation case studies which is simple, synoptic, and suitable for continuous monitoring model based on the fuzzy logic. The model combines topography and vegetation status information to assess soil vulnerability to land degradation. Topographic parameters were obtained from digital elevation models (DEM), and vegetation status information was derived from the computation of the normalized difference vegetation index (NDVI) satellite images. This spectral index provides relevance and is updated for each scene, evidences about the biomass and soil productivity, and vegetation density cover or vegetation stress (e.g., forest fires, droughts). Modeled output maps are suitable for temporal change analysis, which allows the identification of the effect of land management practices, soil and vegetation regeneration, or climate effects
Einstein-Planck Formula, Equivalence Principle, and Black Hole Radiance
The presence of gravity implies corrections to the Einstein-Planck formula E = hν. This gives hope that the divergent blueshift in frequency, associated to the presence of a black hole horizon, could be smoothed out for the energy. Using simple arguments based on Einstein's equivalence principle, we show that this is only possible if a black hole emits, in a first approximation, not just a single particle, but thermal radiation
Physical Properties of Soils Affected by the Use of Agricultural Waste
This chapter provided an overview of the physical properties of soils and their importance on the mobility of water and nutrients and the development of a vegetation cover. It also gives some examples of why the use of agricultural residues can affect positively soil physical properties. The incorporation of agricultural wastes can be a sustainable practice to improve soil characteristics, favoring a model of zero waste in agricultural production and allowing better management of soils. We review and analyze the effect of the use as amendments of different agricultural residues, on physical properties of the soil (e.g., bulk density, porosity, and saturated hydraulic conductivity), especially related to the movement of water in the soil
Leadership, management, quality, and innovation in organ donation: 2019 Kunming recommendations for One Belt & One Road countries
The findings and recommendations of the 2019 consensus conference in organ donation, held in Kunming, China, are here reported. The main objective of the conference was to gather relevant information from experts involved in the field. The data and opinions provided allowed to propose a series of recommendations for “One Belt & One Road Countries” on how to achieve self-sufficiency in organ donation. Leadership in organ donation should be results-oriented and goal-driven based on the principles of excellence, empowerment, and engagement, providing the means, resources, and strategies necessary to reach the goal in earnest. Management includes good governance and transparency of a national registry of patients in the waiting list, donors, transplants, transplant teams, quality, and safety programs with continuous educational training of health care professionals. Mandatory monitoring, auditing and evaluation of quality must be incorporated into donation practices as relevant points in innovation, as well as the adoption of already established and novel processes and technologies. Achievement of self-sufficiency in organ donation is a crucial step to fight against transplant tourism and to prevent organ trafficking. Based on recommendations arising from the conference, each country could review and develop individualized action plans adjusted to its own circumstances and reality
Rare Coding Variants in Patients with Non-Syndromic Vestibular Dysfunction
The following are available online at https://www.mdpi.com/article/
10.3390/genes14040831/s1A.A.M.S. received a scholarship from the Philippine Council for Health and Research
Development of the Department of Science and Technology (PCHRD-DOST) under the Research
Enrichment (Sandwich) Grant of the Accelerated Science and Technology Human Resource Devel-
opment Program. O.A.K. was supported by the US National Institutes of Health (NIH)—National
Institute on Deafness and Other Communication Disorders (NIDCD) grant T32 DC012280 (to Sue C.
Kinnamon and Herman A. Jenkins). This work was supported by the NIH through the NIDCD grants
R01 DC019642 (to R.L.P.S.-C. and Ivana V. Yang) and R01 DC013912 (to S.P.G.); and the National Insti-
tute of Arthritis and Musculoskeletal and Skin Diseases grant R01 AR068292 (to N.H.-M.). Funding
was also provided by Junta de Andalucia, grant Retos en Investigacion PY20_00303 (to J.A.L.-E.).Vertigo due to vestibular dysfunction is rare in children. The elucidation of its etiology will
improve clinical management and the quality of life of patients. Genes for vestibular dysfunction
were previously identified in patients with both hearing loss and vertigo. This study aimed to
identify rare, coding variants in children with peripheral vertigo but no hearing loss, and in patients
with potentially overlapping phenotypes, namely, Meniere’s disease or idiopathic scoliosis. Rare
variants were selected from the exome sequence data of 5 American children with vertigo, 226 Spanish
patients with Meniere’s disease, and 38 European–American probands with scoliosis. In children with
vertigo, 17 variants were found in 15 genes involved in migraine, musculoskeletal phenotypes, and
vestibular development. Three genes, OTOP1, HMX3, and LAMA2, have knockout mouse models for
vestibular dysfunction. Moreover, HMX3 and LAMA2 were expressed in human vestibular tissues.
Rare variants within ECM1, OTOP1, and OTOP2 were each identified in three adult patients with
Meniere’s disease. Additionally, an OTOP1 variant was identified in 11 adolescents with lateral
semicircular canal asymmetry, 10 of whom have scoliosis. We hypothesize that peripheral vestibular
dysfunction in children may be due to multiple rare variants within genes that are involved in the
inner ear structure, migraine, and musculoskeletal disease.Philippine Council for Health and Research Development of the Department of Science and Technology (PCHRD-DOST) under the Research Enrichment (Sandwich) Grant of the Accelerated Science and Technology Human Resource Development ProgramUS National Institutes of Health (NIH)-National Institute on Deafness and Other Communication Disorders (NIDCD)
T32 DC012280NIH through the NIDCD
R01 DC019642,
R01 DC013912United States Department of Health & Human Services
National Institutes of Health (NIH) - USA
NIH National Institute of Arthritis & Musculoskeletal & Skin Diseases (NIAMS)
R01 AR068292Junta de Andalucia
PY20_0030
Performance of Sulfonated Poly(Vinyl Alcohol)/Graphene Oxide Polyelectrolytes for Direct Methanol Fuel Cells
The use of nanotechnology along with the consideration of a functionalization and stabilization approach to poly(vinyl alcohol) (PVA) is considered useful for the preparation of cost-effective polyelectrolyte membranes. A set of nanocomposite and crosslinked membranes based on PVA/sulfosuccinic acid (SSA)/graphene oxide (GO) are prepared and analyzed as polyelectrolytes in direct methanol fuel cells (DMFCs). The crosslinking and sulfonation by the use of SSA enhances the stability and increase the proton-conducting sites in the PVA structure. The presence of GO augments the stability, remarkably decreases the methanol crossover, and enhances power density curves. An optimum value for proton conductivity is found for the 0.50 wt% of GO proportion, which decreases with higher concentrations of GO. Given the power density curve dependency on both the proton conductivity and the crossover reduction, the performance of these membranes as polyelectrolytes in DMFCs is strictly related to the balance between both factors. Therefore, a proportion of GO of 0.75 wt% may assure suitable proton conductivity of 3 mS cm−1 and high resistance to methanol permeability, reaching promising power density of 16 mW cm−2 with lower hydration levels
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