342 research outputs found

    Evaluation of trace-metal concentrations in water consumption of streams near Guajira (Colombia)

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    The spatial distribution of metals in the water for consumption in the different supply sources, natural sources, family storage tanks and deep wells were studied. 16 samples were made for different municipalities belonging to the department of La Guajira upper part. The water samples were analyzed in 2016 and analyzed physically and chemically and microbiologically. The results were compared with national standards and those established by the WHO. The results found show some traces of metals in some of the sampling sites. The concentrations of Calcium, Magnesium exceeded the concentrations established by the standards. The results reinforce the need for better control of the physicochemical and microbiological parameters of the water consumed by the population

    Distal corporal anchoring stitch: a technique to address distal corporal crossovers and impending lateral extrusions of a penile prosthesis

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    Background: Unidentified distal crossovers, delayed distal crossovers, and impending lateral extrusion are complications of penile prosthesis implant insertion but are not as common as prosthesis infection or mechanical failure. Aim: To evaluate results of a surgical technique, the distal corporal anchoring stitch, that addresses fixation of the penile prosthesis in patients with these complications. Methods: A lateral sub-coronal incision is used on the side where the crossover or laterally extruding cylinder should be positioned. Dissection is carried through the Buck fascia, followed by a transverse incision of the tunica albuginea, where the distal aspect of the affected cylinder is delivered. A 4-0 PDS suture is threaded through the distal cylinder ring of the implant. A new, properly positioned intracorporal channel is created and the suture is passed through the distal end of the channel. Once the suture is through the glans and the cylinder is in the correct position, a small cruciate incision is made on the glans at the location of the anchor stitch. The suture is tied with the knot buried in the glans tissue. Outcomes: Fifty-three patients underwent treatment of their distal penile implant crossover with a distal corporoplasty using this method and their anatomic and functional outcomes and overall satisfaction were evaluated. Results: This technique ensured that the cylinder remained in the newly created, appropriately positioned channel. No patients developed infections, wound-healing defect, glandular hypoesthesia, anesthesia, or altered sensation or pain in the glans related to the suture and only two reported recurrence of a lateral herniation that did not require further treatment. Clinical Implications: Distal fixation of the penile prosthesis is a useful surgical adjunct to treating patients with prosthetic lateral extrusions or crossovers that can be applied in almost all cases. Strengths and Limitations: Considering these rare complications, our experience is based on a relatively large number of patients and showed a low incidence of complications and a high satisfaction rate. The main limitation of this study is the retrospective nature of the data and the series included patients from two high-volume surgeons that might not be generalizable to all practices. Conclusion: The distal corporal anchoring stitch is safe and effective in securing distal fixation of the extruding inflatable penile prosthesis

    Applicability of the national policy of environmental education in educational institutions

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    La educación ambiental es un proceso que incentiva el desarrollo de capacidades para compatibilizar las actividades del hombre sobre el medio ambiente, a razón de esto, Colombia adoptó la Política Nacional de Educación Ambiental que orienta a la implementación de Proyectos Ambientales Escolares-PRAE. Esta investigación buscó analizar la aplicabilidad de esta Política mediante un comparativo entre los lineamientos de la política de educación ambiental y el estado actual de las actividades de las instituciones educativas (IE) enmarcadas en la educación ambiental. Esto se realizó mediante la utilización de la herramienta “talleres aplicados” cuya finalidad fue la recolección primaria del grupo de estudio, entre los resultados encontrados se evidenció un desconocimiento en las instituciones educativas sobre los ejes temáticos y líneas de trabajos de los PRAE, dificultades en la divulgación del PRAE en toda la institución y poco apoyo administrativo para la implementación respectivamente. En general los resultados indican que las actividades relacionadas a la temática ambiental están rezagadas a las áreas de conocimiento de ciencias naturales y estos a su vez no son coherentes con los PRA

    Azimuthal asymmetry in the risetime of the surface detector signals of the Pierre Auger Observatory

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    The azimuthal asymmetry in the risetime of signals in Auger surface detector stations is a source of information on shower development. The azimuthal asymmetry is due to a combination of the longitudinal evolution of the shower and geometrical effects related to the angles of incidence of the particles into the detectors. The magnitude of the effect depends upon the zenith angle and state of development of the shower and thus provides a novel observable, (secθ)max(\sec \theta)_\mathrm{max}, sensitive to the mass composition of cosmic rays above 3×10183 \times 10^{18} eV. By comparing measurements with predictions from shower simulations, we find for both of our adopted models of hadronic physics (QGSJETII-04 and EPOS-LHC) an indication that the mean cosmic-ray mass increases slowly with energy, as has been inferred from other studies. However, the mass estimates are dependent on the shower model and on the range of distance from the shower core selected. Thus the method has uncovered further deficiencies in our understanding of shower modelling that must be resolved before the mass composition can be inferred from (secθ)max(\sec \theta)_\mathrm{max}.Comment: Replaced with published version. Added journal reference and DO

    Calibration of the Logarithmic-Periodic Dipole Antenna (LPDA) Radio Stations at the Pierre Auger Observatory using an Octocopter

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    An in-situ calibration of a logarithmic periodic dipole antenna with a frequency coverage of 30 MHz to 80 MHz is performed. Such antennas are part of a radio station system used for detection of cosmic ray induced air showers at the Engineering Radio Array of the Pierre Auger Observatory, the so-called Auger Engineering Radio Array (AERA). The directional and frequency characteristics of the broadband antenna are investigated using a remotely piloted aircraft (RPA) carrying a small transmitting antenna. The antenna sensitivity is described by the vector effective length relating the measured voltage with the electric-field components perpendicular to the incoming signal direction. The horizontal and meridional components are determined with an overall uncertainty of 7.4^{+0.9}_{-0.3} % and 10.3^{+2.8}_{-1.7} % respectively. The measurement is used to correct a simulated response of the frequency and directional response of the antenna. In addition, the influence of the ground conductivity and permittivity on the antenna response is simulated. Both have a negligible influence given the ground conditions measured at the detector site. The overall uncertainties of the vector effective length components result in an uncertainty of 8.8^{+2.1}_{-1.3} % in the square root of the energy fluence for incoming signal directions with zenith angles smaller than 60{\deg}.Comment: Published version. Updated online abstract only. Manuscript is unchanged with respect to v2. 39 pages, 15 figures, 2 table

    Multi-resolution anisotropy studies of ultrahigh-energy cosmic rays detected at the Pierre Auger Observatory

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    We report a multi-resolution search for anisotropies in the arrival directions of cosmic rays detected at the Pierre Auger Observatory with local zenith angles up to 8080^\circ and energies in excess of 4 EeV (4×10184 \times 10^{18} eV). This search is conducted by measuring the angular power spectrum and performing a needlet wavelet analysis in two independent energy ranges. Both analyses are complementary since the angular power spectrum achieves a better performance in identifying large-scale patterns while the needlet wavelet analysis, considering the parameters used in this work, presents a higher efficiency in detecting smaller-scale anisotropies, potentially providing directional information on any observed anisotropies. No deviation from isotropy is observed on any angular scale in the energy range between 4 and 8 EeV. Above 8 EeV, an indication for a dipole moment is captured; while no other deviation from isotropy is observed for moments beyond the dipole one. The corresponding pp-values obtained after accounting for searches blindly performed at several angular scales, are 1.3×1051.3 \times 10^{-5} in the case of the angular power spectrum, and 2.5×1032.5 \times 10^{-3} in the case of the needlet analysis. While these results are consistent with previous reports making use of the same data set, they provide extensions of the previous works through the thorough scans of the angular scales.Comment: Published version. Added journal reference and DOI. Added Report Numbe

    Ultrahigh-energy neutrino follow-up of Gravitational Wave events GW150914 and GW151226 with the Pierre Auger Observatory

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    On September 14, 2015 the Advanced LIGO detectors observed their first gravitational-wave (GW) transient GW150914. This was followed by a second GW event observed on December 26, 2015. Both events were inferred to have arisen from the merger of black holes in binary systems. Such a system may emit neutrinos if there are magnetic fields and disk debris remaining from the formation of the two black holes. With the surface detector array of the Pierre Auger Observatory we can search for neutrinos with energy above 100 PeV from point-like sources across the sky with equatorial declination from about -65 deg. to +60 deg., and in particular from a fraction of the 90% confidence-level (CL) inferred positions in the sky of GW150914 and GW151226. A targeted search for highly-inclined extensive air showers, produced either by interactions of downward-going neutrinos of all flavors in the atmosphere or by the decays of tau leptons originating from tau-neutrino interactions in the Earth's crust (Earth-skimming neutrinos), yielded no candidates in the Auger data collected within ±500\pm 500 s around or 1 day after the coordinated universal time (UTC) of GW150914 and GW151226, as well as in the same search periods relative to the UTC time of the GW candidate event LVT151012. From the non-observation we constrain the amount of energy radiated in ultrahigh-energy neutrinos from such remarkable events.Comment: Published version. Added journal reference and DOI. Added Report Numbe
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