4,772 research outputs found
An Assessment on the Use of Stationary Vehicles as a Support to Cooperative Positioning
In this paper, we consider the use of stationary vehicles as tools to enhance
the localisation capabilities of moving vehicles in a VANET. We examine the
idea in terms of its potential benefits, technical requirements, algorithmic
design and experimental evaluation. Simulation results are given to illustrate
the efficacy of the technique.Comment: This version of the paper is an updated version of the initial
submission, where some initial comments of reviewers have been taken into
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Historic preservation and disaster resilience : flooding in Santiago de Querétaro, Mexico
textSantiago de Querétaro is a UNESCO World Heritage City in central Mexico experiencing exacerbating rates of flooding in its historic center due to increased uphill urbanization overwhelming the aging drainage infrastructure. Historic districts are important economic drivers and shrines of heritage that should be considered when planning for disaster resiliency. This Report explores flood mitigation considerations for historic structures and districts, identifying those best suited for Querétaro and can be implemented at the parcel, district, or public administrative levels.Community and Regional Plannin
Evaluaci?n de la actividad bactericida de fracciones enriquecidas en flavonoides a partir de: psidium guajava l. (guayaba), calendula officinalis l. (cal?ndula), l. (romero) y matricaria chamomilla l. (manzanilla) sobre: erwinia carotovora (dye).
88 P?ginasLas plantas alimenticias son infectadas por bacterias originando graves problemas fitosanitarios que generan p?rdidas econ?micas a los agricultores. Estos microorganismos desarrollan resistencia hacia los antibi?ticos debido a su uso inadecuado. Una alternativa en el control de bacterias fitopat?genas es el empleo de extractos bot?nicos, con lo cual se busca reducir el impacto econ?mico y ambiental en el sector agr?cola.
Empleando diversos ?rganos de Psidium guajava L. (guayaba), Calendula officinalis L. (cal?ndula), Rosmarinus officinalis L. (romero) y Matricaria chamomilla L. (manzanilla) se elaboraron extractos etan?licos, de los cuales se obtuvieron cuatro (4) fracciones mediante una serie eluotr?pica de solventes (?ter de petr?leo, acetato de etilo, n-butanol y agua).
Los extractos y sus fracciones fueron caracterizados fitoqu?micamente con cromatograf?as en capa delgada para detectar flavonoides (fracci?n et?rea descartada) y su actividad in vitro se evalu? frente a la cepa E. carotovora mediante el m?todo de inhibici?n zonal (m?todo de difusi?n en agar), utilizando concentraciones de 5.000, 7.000 y 10.000 (?g/mL), con mediciones de halos de inhibici?n a las 24 y 48 horas. Los resultados obtenidos mediante estas pruebas determinaron un control positivo de las plantas P. guajava con su extracto etan?lico y sus 3 fracciones y C. officinalis en su fracci?n acetato de etilo.
Los resultados obtenidos a partir del estudio de actividad biol?gica in vitro sugieren que las fracciones n-butanol y acuosa en la especia P. guajava y la fracci?n acetato de etilo en la especia C. officinalis son promisorias para futuros ensayos de actividad bactericida y otros estudios qu?micos.ABSTRACT
Food plants are infected by causing serious phytosanitary problems caused economic losses to farmers bacteria. These microorganisms develop resistance to antibiotics due to improper use. An alternative in the control of plant pathogenic bacteria is the use of botanical extracts, which seeks to reduce the economic and environmental impact on the agricultural sector.
Using various organs of Psidium guajava L. ( guava), Calendula officinalis L. (marigold), Rosmarinus officinalis L. (rosemary ) and Matricaria chamomilla L. (chamomile ) ethanol extracts were prepared , of which four (4) fractions were obtained by eluotropic series of solvents (petroleum ether, ethyl acetate, n-butanol and water).
The extracts and fractions were characterized phytochemically with thin layer chromatography for any flavonoids (ethereal fraction discarded) and its in vitro activity was evaluated against strain E. carotovora by the method of zonal inhibition (diffusion method on agar) using concentrations of 5.000, 7.000 and 10.000 (?g/mL), with measurements of zones of inhibition at 24 and 48 hours. The results obtained by these tests determined a positive control of plants with P. guajava ethanol extract and its fractions and its 3 in the C. officinalis ethyl acetate fraction.
The results obtained from the study of biological activity in vitro suggest that n - butanol fraction and water at P. guajava spice and ethyl acetate fraction in the spice C. officinalis are promising for future trials and other studies bactericidal activity chemicals.INTRODUCCI?N
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1. MARCO TE?RICO
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1.1 IMPORTANCIA DE LAS ENFERMEDADES FITOPAT?GENAS
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1.2 FITOENFERMEDADES POR BACTERIAS
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1.3 CONTROL DE BACTERIAS FITOPAT?GENAS
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1.3.1 Uso de Antibi?ticos
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1.4 EXTRACTOS VEGETALES Y SU PAPEL EN LA AGRICULTURA
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1.4.1 Uso Mundial, Regional y Local.
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1.4.2 Uso en el campo.
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1.5 DESCRIPCI?N DE E. carotovora.
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1.5.1 Generalidades.
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1.5.2 Situaci?n actual
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1.5.3 Identificaci?n taxon?mica seg?n la N.C.B.I.
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1.5.4 Tratamiento
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1.5.5 Incidencia.
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1.6 DESCRIPCI?N BOT?NICA DE LAS ESPECIES VEGETALES
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1.6.1 Descripci?n bot?nica P. guajava
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1.6.1.1 Flavonoides reportados y actividad biol?gica
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1.6.2 Descripci?n bot?nica R. officinalis
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1.6.2.1 Flavonoides reportados y actividad biol?gica
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1.6.3 Descripci?n bot?nica C. officinalis
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1.6.3.1 Flavonoides reportados y actividad biol?gica
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1.6.4 Descripci?n bot?nica M. Chamomilla
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1.6.4.1 Flavonoides reportados y actividad biol?gica
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1.7 FLAVONOIDES
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2. PARTE EXPERIMENTAL
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2.1 EQUIPOS REACTIVOS Y MATERIALES
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2.1.1 Equipos
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2.1.2 Reactivos
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2.1.3 Materiales
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2.2 MATERIAL VEGETAL
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2.2.1 Material microbiol?gico
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2.3 METODOLOGIA - ENSAYOS FITOQUIMICOS
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2.3.1 Elaboraci?n de los extractos etan?licos de P. guajava, C. officinalis, R. officinalis y M. chamomilla
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2.3.2 Fraccionamiento del extracto etan?lico
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2.3.3 Detecci?n de flavonoides en extractos etan?licos y fracciones primarias de P. guajava, C. officinalis, R. officinalis y M. chamomilla
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2.4 METODOLOG?A BIOL?GICA
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2.4.1 Bioensayo de la actividad bactericida de los extractos y fracciones sobre E. carotovora
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2.4.2 Determinaci?n de la concentraci?n inhibitoria para el control positivo (Cefalexina)
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2.4.3 Disoluci?n de los extractos etan?licos y fracciones primarias
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2.5 AN?LISIS ESTAD?STICO
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2.5.1 M?todo estad?stico
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3. RESULTADOS Y DISCUSI?N
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3.1 EXTRACCI?N Y FRACCIONAMIENTO DE LOS EXTRACTOS ETAN?LICOS
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3.2 ESTUDIO FITOQU?MICO POR CCD DE LOS EXTRACTOS Y FRACCIONES
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3.2.1 An?lisis de los extractos
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3.2.2 An?lisis de las fracciones
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3.3 PRUEBAS DE ACTIVIDAD BIOL?GICA IN VITRO DE LOS EXTRACTOS ETAN?LICOS Y FRACCIONES OBTENIDAS DE P. GUAJAVA, R. OFFICINALIS, C. OFFICINALIS Y M.CHAMOMILLA SOBRE E. CAROTOVORA
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3.4 RESULTADOS AN?LISIS ESTAD?STICO
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4. CONCLUSIONES Y RECOMENDACIONES
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4.1 CONCLUSIONES
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4.2 RECOMENDACIONES
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5. REFERENCIAS
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Physical properties of seven binary and higher-order multiple OB systems
Analyses of multi-epoch, high-resolution (~ 50000) optical spectra of seven
early-type systems provided various important new insights with respect to
their multiplicity. First determinations of orbital periods were made for HD
92206C (2.022 d), HD 112244 (27.665 d), HD 164438 (10.25 d), HD 123056A (~ 1314
d) and HD 123056B (< 2 d); the orbital period of HD 318015 could be improved
(23.445975 d). Concerning multiplicity, a third component was discovered for HD
92206C by means of He I line profiles. For HD 93146A, which was hitherto
assumed to be SB1, lines of a secondary component could be discerned. HD 123056
turns out to be a multiple system consisting of a high-mass component A (~
O8.5) displaying a broad He II 5411 A feature with variable radial velocity,
and of an inner pair B (~ B0) with double He I lines. The binary HD 164816 was
revisited and some of its system parameters were improved. In particular, we
determined its systemic velocity to be -7 km/s, which coincides with the radial
velocity of the cluster NGC 6530. This fact, together with its distance,
suggests the cluster membership of HD 164816. The OB system HD 318015 (V1082
Sco) belongs to the rare class of eclipsing binaries with a supergiant primary
(B0.5/0.7). Our combined orbital and light-curve analysis suggests that the
secondary resembles an O9.5III star. Our results for a limited sample
corroborate the findings that many O stars are actually massive multiple
systems.Comment: 16 pages, 16 figures, to appear in Astronomy and Astrophysic
An assessment on the use of stationary vehicles to support cooperative positioning systems
In this paper, we evaluate the ability of stationary vehicles (e.g. parked or temporary stopped cars) as tools to enhance the capabilities of existing cooperative positioning algorithms in vehicular networks. First, some real-world facts are provided to support the feasibility of our ideas. Then, we examine the idea in greater details in terms of the technical requirements and methodological analysis, and provide a comprehensive experimental evaluation using dedicated simulations. The routing of a drone through an urban scenario is presented as a non-traditional application case, where the benefits of the proposed approach are reflected in a better utilisation of the flight time
Experimental Evidence of Generation and Reception by a Transluminal Axisymmetric Shear Wave Elastography Prototype
Experimental evidence on testing a non-ultrasonic-based probe for a new approach in transluminal elastography was presented. The proposed modality generated shear waves by inducing oscillatory rotation on the lumen wall. Detection of the propagated waves was achieved at a set of receivers in mechanical contact with the lumen wall. The excitation element of the probe was an electromagnetic rotational actuator whilst the sensing element was comprised by a uniform anglewise arrangement of four piezoelectric receivers. The prototype was tested in two soft-tissue-mimicking phantoms that contained lumenlike conduits and stiffer inclusions. The shear wave speed of the different components of the phantoms was characterized using shear wave elastography. These values were used to estimate the time-of-flight of the expected reflections. Ultrafast ultrasound imaging, based on Loupas' algorithm, was used to estimate the displacement field in transversal planes to the lumenlike conduit and to compare against the readouts from the transluminal transmission-reception tests. Experimental observations between ultrafast imaging and the transluminal probe were in good agreement, and reflections due to the stiffer inclusions were detected by the transluminal probe. The obtained experimental evidence provided proof-of-concept for the transluminal elastography probe and encouraged further exploration of clinical applications
Nonlinear dynamics of Long-Wavelength VCSELs subject to polarised optical injection
We present our work analysing the effects of polarised optical injection in Long-Wavelength Vertical-Cavity Surface Emitting Lasers (LW-VCSELs). We review the properties of different phenomena such as polarisation switching (PS) and bistability (PB) as well as on the different nonlinear dynamics (periodic and chaotic) arising in these devices under different cases of polarised optical injection. © 2011 IEEE
When the Earth trembles in the americas: the experience of haiti and chile 2010.
The response of the nephrological community to the Haiti and Chile earthquakes which occurred in the first months of 2010 is described. In Haiti, renal support was organized by the Renal Disaster Relief Task Force (RDRTF) of the International Society of Nephrology (ISN) in close collaboration with Médecins Sans Frontières (MSF), and covered both patients with acute kidney injury (AKI) and patients with chronic kidney disease (CKD). The majority of AKI patients (19/27) suffered from crush syndrome and recovered their kidney function. The remaining 8 patients with AKI showed acute-to-chronic renal failure with very low recovery rates. The intervention of the RDRTF-ISN involved 25 volunteers of 9 nationalities, lasted exactly 2 months, and was characterized by major organizational difficulties and problems to create awareness among other rescue teams regarding the availability of dialysis possibilities. Part of the Haitian patients with AKI reached the Dominican Republic (DR) and received their therapy there. The nephrological community in the DR was able to cope with this extra patient load. In both Haiti and the DR, dialysis treatment was able to be prevented in at least 40 patients by screening and adequate fluid administration. Since laboratory facilities were destroyed in Port-au-Prince and were thus lacking during the first weeks of the intervention, the use from the very beginning on of a point-of-care device (i-STAT®) was very efficient for the detection of aberrant kidney function and electrolyte parameters. In Chile, nephrological problems were essentially related to difficulties delivering dialysis treatment to CKD patients, due to the damage to several units. This necessitated the reallocation of patients and the adaptation of their schedules. The problems could be handled by the local nephrologists. These observations illustrate that local and international preparedness might be life-saving if renal problems occur in earthquake circumstances
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