296 research outputs found
Karl Otto Apel y el problema de la fundamentación de la ética en la época de la ciencia : (un aporte para la superación de la dicotomía entre la objetividad de la ciencia y la subjetividad de la ética o entre lo público y lo privado)
Ningun
Assessment of the Contribution of Polarimetric Persistent Scatterer Interferometry on Sentinel-1 Data
Time series of Sentinel-1 data are widely used for monitoring displacements of the Earth surface using persistent scatterer interferometry. By default over land, Sentinel-1 images include two polarimetric channels: VV and VH. However, most works in this application exploit only the VV channel, whereas the VH channel is discarded for its lower amplitude. Thanks to the development of polarimetric persistent scatterer interferometry methods, one can integrate multi-polarisation channels into a single optimal one. Previous studies proved that the number and spatial density of measurement points is increased. In this work, we explore the reason why the VH channel increases the number of measurement points when using the amplitude dispersion ( DA ) as selection criterion. Results obtained over three geographical locations show that the VH channel helps in two ways. In first place, the mean amplitude is increased for targets which have higher amplitude in VH channel, usually associated with rotated elements in the scene. In second place, and more importantly, the amplitude dispersion is decreased over many areas for which the VV channel exhibits fluctuations and peaks. Thanks to the insensitivity of the VH channel to these scene changes, it provides additional measurement points which are reliable despite their low amplitude. The increment of measurement points not only extends the spatial density and enables the detection of active deformation areas not found in the VV results, but also provides more accurate results than only using the VV channel, thanks to the increased density of points, which helps the deformation estimation.This work was supported by the Spanish Ministry of Science and Innovation (State Agency of Research, AEI) and the European Funds for Regional Development (EFRD) under Projects PID2020-117303GB-C21 and PID2020-117303GB-C22. The research was carried out partially in the framework of the ESA-MOST China DRAGON-5 project with ref. 59339
A new Neocalamites (Sphenophyta) with prickles and attached cones from the Upper Triassic of China
Remains of the extinct sphenophyte (horsetail) . Neocalamites are most widespread in the Middle-Upper Triassic and are typically represented by stem and leaf fragments. Here we report on spectacular new finds of . Neocalamites from the Late Triassic Yangcaogou Formation in Liaoning Province, China that include bedding surfaces dominated by nearly complete aerial stems with attached leaf whorls and rare bractless cones. They reveal a monopodial growth habit for the stems, which are covered with downward projecting prickles that probably provided protection against herbivores. These features provide the basis for a new proposed species, . Neocalamites horridus. The nodes bear whorls of very long leaves mainly free to their bases, and one specimen bears an attached cone on a long peduncle. Identical dispersed cones have also been recovered. The leaves of adjacent monopodial stems most likely interlocked to support growth in large stands akin to the role now played by branches in large modern . Equisetum species. The new Chinese . Neocalamites is among the most confidently reconstructed species, and indicates a greater diversity of sphenophyte morphology during the Mesozoic than previously realized.Fil: Zan, Shuqin. Geological Museum Of China; ChinaFil: Axsmith, Brian J.. University of Alabama at Birmingahm; Estados UnidosFil: Escapa, Ignacio Hernán. Museo Paleontológico Egidio Feruglio; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Fraser, Nicholas. National Museum Of Scotland; Reino UnidoFil: Liu, Feng Xiang. Geological Museum Of China; ChinaFil: Xing, De-He. Shenyang Institute Of Geology And Mineral Resources; Chin
Experiencia y resultados preliminares en el uso de cilindros intersomáticos para la artrodesis lumbar
El dolor lumbar crónico es una patología que puede llegar a ser incapacitante y en la que a menudo fracasan los tratamientos conservadores. Como alternativa entre las cirugías que pretenden atajar este problema mediante una artrodesis está la fusión intersomática con cilindros, que presenta algunas ventajas respecto a otras técnicas de fijación. Esta técnica ha sido introducida recientemente en nuestro país. Se presentan los primeros resultados obtenidos tras esta cirugía en los primeros 16 pacientes operados. Desde 1997 a diciembre de 2000 se han implantado 11 cilindros BAK y 5 LIFEC. Diez pacientes tenían un seguimiento mínimo de 1 año y éstos constituyen la serie evaluada. Siete pacientes (70%) no presentaban dolor. Cuatro pacientes (40%) se habían incorporado a sus trabajos respectivos. Seis pacientes (60%) no precisaban tratamiento médico. Los buenos resultados obtenidos hasta el momento nos invitan a pensar que esta técnica, de menor agresividad y que no cierra la puerta a otros tipos de instrumentación, es una opción válida para el tratamiento del dolor lumbar crónico.Chronic low back pain is a medical cause of disability in which conservative management is often not effective. As an alternative, interbody fusion with cylinders offers several advantages as compared to other surgical methods of fusion. This technique has been recently introduced in our Country. The preliminary results of 16 patients managed in our Department are shown. From 1997 to December 2000, eleven BAK devices and 5 LIFEC have been implanted. Ten patients had a minimum follow-up of 1 year and these constitute the series evaluated. Seven patients (70%) were free of pain. Four patients (40%) returned to their previous job. Six patients (60%) did not need medical treatment. The good results with this technique encourage us and suggest that these devices are a valid option for the management of chronic low back pain
Prótesis unicondílea de rodilla: Valoración clínica preliminar
Los pacientes afectados de artrosis unicompartimetal de rodilla pueden ser tratados con diferentes métodos quirúrgicos. Los más habituales son la osteonomía tibial en jóvenes y la prótesis total de rodilla en ancianos. Una alternativa que va adquiriendo adeptos es la prótesis unicondílea. Tras un período inicial de gran euforia se pasó a otro de escepticismo, dando los resultados. El propósito del presente estudio es evaluar un nuevo diseño de prótesis de rodilla unicondílea (Alpina, IQL) a corto plazo siguiendo criterios clínicos y de calidad de vida. Se revisan 13 pacientes intervenidos entre Junio de 2000 a Marzo del 2002. Siete eran varones y seis mujeres. La edad media fue de 65 años (r=55-72ª). En doce casos la etiología fue artrosis y en uno necrosis del cóndilo interno. La evaluación clínica se realizó mediante el cuestionario sobre la calidad de vida SF-12. Todos los pacientes consiguieron una flexión de 110º y extensión completa. Sólo un paciente presentó molestias leves.Patients who have unicompartimental knee osteoarthritis can be manager by different surgical techniques. Young people are usually treated by tibial osteotomy and elderly people by total knee replacement. Unicondylar knee prosthesis is becoming an attractive recognized alternative. After a period of enthusiastic regarding this technique, scepticism took place based on the clinical results. The aim of this study is to evaluate, in firs instance, a new knee unicondylar knee prosthesis design (Alpine, IQL) following clinical criteria and quality of life. Thirteen patients, managed in between June 2000 and March 2002, are reviewed. Seven were males and six females. The mean age was 65 years (range 55-77 years). Osteoarthritis was the aetiology in twelve cases and necrosis of the medial condyle in one patient. The clinical evaluation was based on quality of life through a questionnaire SF-12. All patients improved a knee flexion of 110º and a complete extension. Only one patient had slight pain and had some limitation
Managing Change and Master Plans: Machu Picchu Between Conservation and Exploitation
Machu Picchu is among the world\u2019s most controversial heritage sites. It represents a case where raising money through ticket sales and other activities, rather than an opportunity to fund site preservation, in fact constitutes a major threat to the survival of the site through overexploitation. Unesco has been very critical in recent decades about the management of Machu Picchu. International pressure resulted in the establishment of two master plans, in 1998 and in 2005. In this paper we investigate in depth the contents and rhetoric of the two plans, comparing changes in the two different versions, and linking the change in planning attitude to actual changes taking place in the site. This is also an opportunity to open a discussion on the interdisciplinarity of master plans in heritage sites
Cerebrospinal Fluid Viral Load Across the Spectrum of Untreated Human Immunodeficiency Virus Type 1 (HIV-1) Infection: A Cross-Sectional Multicenter Study
Background The aim of this large multicenter study was to determine variations in cerebrospinal fluid (CSF) HIV-RNA in different phases of untreated human immunodeficiency virus type 1 (HIV-1) infection and its associations with plasma HIV-RNA and other biomarkers. Methods Treatment naive adults with available CSF HIV-RNA quantification were included and divided into groups representing significant disease phases. Plasma HIV-RNA, CSF white blood cell count (WBC), neopterin, and albumin ratio were included when available. Results In total, 1018 patients were included. CSF HIV-RNA was in median (interquartile range [IQR]) 1.03 log(10) (0.37-1.86) copies/mL lower than in plasma, and correlated with plasma HIV-RNA (r = 0.44, P < .01), neopterin concentration in CSF (r = 0.49, P < .01) and in serum (r = 0.29, P < .01), CSF WBC (r = 0.34, P < .01) and albumin ratio (r = 0.25, P < .01). CSF HIV-RNA paralleled plasma HIV-RNA in all groups except neuroasymptomatic patients with advanced immunodeficiency (CD4 < 200) and patients with HIV-associated dementia (HAD) or opportunistic central nervous system (CNS) infections. Patients with HAD had the highest CSF HIV-RNA (in median [IQR] 4.73 (3.84-5.35) log(10) copies/mL). CSF > plasma discordance was found in 126 of 972 individuals (13%) and varied between groups, from 1% in primary HIV, 11% in neuroasymptomatic groups, up to 30% of patients with HAD. Conclusions Our study confirms previous smaller observations of variations in CSF HIV-RNA in different stages of HIV disease. Overall, CSF HIV-RNA was approximately 1 log(10) copies/mL lower in CSF than in plasma, but CSF discordance was found in a substantial minority of subjects, most commonly in patients with HAD, indicating increasing CNS compartmentalization paralleling disease progression. HIV-RNA is detectable in cerebrospinal fluid (CSF) across all stages of untreated HIV and usually parallel plasma HIV-RNA at a lower level. A substantial proportion (13%) of patients have CSF>plasma HIV-RNA, most commonly in patients with HIV-associated dementia
Growth Kinetics in Layer‐by‐Layer Assemblies of Organic Nanoparticles and Polyelectrolytes
The growth rates of layer‐by‐layer (LbL) assemblies of polyelectrolytes (PEs) with oppositely charged polystyrene (PS) nanoparticles (NPs) as a function of molecular weight (MW) of the PEs, ionic strength of the media, and NP size and charge are systematically investigated. To optimize LbL growth, the effects of suspension concentration, pH of the media, and deposition time on the growth rate of multilayers are assessed. Both linear and exponential growth behaviors are observed and, under optimal conditions, films of up to around 1 μm thick can readily be assembled after 10 or so bilayers have been deposited. For many of the cases studied, an intermediate MW of PE leads to the fastest film buildup, for both cationic poly(ethyleneimine) deposited alternately with anionic PS NPs and for anionic poly(acrylic acid) deposited alternately with cationic PS NPs. The existence of an optimal MW suggests that growth rate is determined by a balance of thermodynamic factors, including density of polymer bridges between particles, and kinetic factors, specifically the diffusivity of polymer in the film. The optimal MW, however, is very sensitive to the materials used. Moreover, depending on the MW of the PE, increasing salinity could increase or decrease the growth kinetics. Finally, the surface morphology of the films is characterized with AFM and SEM to reveal that the roughness increases less than linearly with film thickness.Growth factors: The growth rates of layer‐by‐layer (LbL) assemblies of polyelectrolytes (PEs) with oppositely charged polystyrene nanoparticles are systematically investigated. The molecular weight of a PE has a considerable effect on LbL film growth and its surface morphology (see figure).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135666/1/cphc201600789_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/135666/2/cphc201600789-sup-0001-misc_information.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/135666/3/cphc201600789.pd
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