Efecto de la inclusión en la dieta de hidrolizado proteico de pescado sobre el crecimiento corporal y composición proximal del músculo de doncella (Pseudoplatystoma punctifer)

The effect of including fish protein hydrolyzate in the diet on body growth and proximate composition of the muscle of juvenile spotted tiger shovelnose catfish (Pseudoplatystoma punctifer) was evaluated. A completely randomized experimental design with a 2x4 factorial arrangement (2 diets, 4 sampling times [days 15, 30, 45 and 60]) was used, resulting in 8 treatments with 3 replications each. The formulated diets were isocaloric (42.15% CP) and isoproteic (4 415.69 kcal EB kg-1): a control (DT; without supplementation) and another with the inclusion of 1.20% fish protein hydrolyzate (DHP) in substitution of fishmeal. A total of 114 juveniles (642.65 g; 47.93 cm) were distributed in excavated ponds of 200 m2 (19 fish/pond) for 60 days. Every 15 days, eight fish per experimental unit were captured to evaluate body growth (final weight FW, final length FL, weight gain WG, length gain LG, specific growth rate SGR, feed conversion FC, protein efficiency rate PER). survival S and condition factor CF). In addition, three fish per experimental unit on days 0 and 60 of the experiment were slaughtered for muscle chemical composition analysis. DHP did not affect FL, LG, PER, S, CF, or proximal muscle composition; however, the fish fed with the DHP diet presented better performance expressed in FW (1049.17 g vs. 919.56 g), WG (406.52 g vs. 276.91 g) and SGR (0.82 vs. 0.60) at 60 days of feeding, as well as better CF compared to the diet without supplementation.Se evaluó el efecto de la inclusión en la dieta de hidrolizado proteico de pescado sobre el crecimiento corporal y la composición química del músculo de juveniles de doncella.  El estudio siguió un diseño experimental completamente al azar con un arreglo factorial de 2 x 4 [2 dietas vs. 4 tiempos de muestreo (15°, 30°, 45° y 60° día)], resultando en 8 tratamiento con 3 repeticiones cada uno. Los tratamientos fueron: T1: DT15; T2: DHP15; T3: DT30;  T4: DHP30; T5: DT45; T6: DHP45; T7: DT60 y T8: DHP60. Las dietas formuladas fueron isocalóricas (42.15% PB) e isoproteicas (4,415.69 kcal EB kg-1): una testigo (DT; sin suplementación) y otra con inclusión de 1.20% de hidrolizado proteico de pescado (DHP) en substitución de la harina de pescado. Un total de 114 doncellas (642.65 g; 47.93 cm) fueron distribuidas en estanques excavados de 200 m2 (19 peces/estanque) y alimentadas con las dietas experimentales durante 60 días. Cada 15 días, ocho peces por unidad experimental fueron capturados para evaluar el crecimiento corporal de los animales (peso final PF, longitud final LF, ganancia de peso GP, ganancia de longitud GL, tasa de crecimiento específico TCE, conversión alimenticia CA, tasa de eficiencia proteica TEP, sobrevivencia S y factor de condición FC). Adicionalmente, al iniciar (día 0) y finalizar (día 60) el experimento tres peces por unidad experimental fueron sacrificados por punción cerebral para análisis de composición química del músculo. DHP no afectó la LT, GL, TEP, S, FC, ni la composición proximal del músculo de doncella; sin embargo, juveniles de esta especie alimentados con dieta suplementada presentaron mejor desempeño expresados en PF (1049.17 g vs. 919.56 g), GP (406.52 g vs. 276.91 g)y TCE (0.82 vs. 0.60) a los 60 días de alimentación, así como mejor CA en comparación con la dieta sin suplementación

Informe de la expedición científica UCR-UNA-COCO-VI

El proyecto “Interacción océano-atmósfera y la biodiversidad marina del Parque Nacional Isla del Coco, Costa Rica” es financiado por el Consejo Nacional de Rectores (CONARE). Del 6 al 14 de julio del 2012, un grupo de científicos del Centro de Investigación en Ciencias del Mar y Limnología (CIMAR) de la Universidad de Costa Rica, y del Servicio Regional de Información Oceanográfica (SERIO)de la Universidad Nacional realizaron la Expedición UCR-UNA-COCO-VI. Para esta expedición se utilizó el barco B/I Undersea Hunter, con un excelente apoyo de la tripulación. Con esta expedición se continúa con la fase oceanográfica de este nuevo proyecto de investigación en la Zona económica Exclusiva de Costa Rica y los alrededores del Parque Nacional Isla del Coco. El estudio se llevó a cabo a lo largo de tres transeptos en la dirección norte-sur centrados en la Isla del Coco, con una longitud de 160 mn cada uno, y en los cuales se ubicaron 26 estaciones de muestreo.CONARE, UCR, UNAUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Ciencias del Mar y Limnología (CIMAR)UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones Geofísicas (CIGEFI

Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO

Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principle calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI. Supplemental material in the ancillary file

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

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

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 $80^\circ$ and energies in excess of 4 EeV ($4 \times 10^{18}$ 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 $p$-values obtained after accounting for searches blindly performed at several angular scales, are $1.3 \times 10^{-5}$ in the case of the angular power spectrum, and $2.5 \times 10^{-3}$ 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

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 $\pm 500$ 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

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

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, $(\sec \theta)_\mathrm{max}$, sensitive to the mass composition of cosmic rays above $3 \times 10^{18}$ 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 $(\sec \theta)_\mathrm{max}$.Comment: Replaced with published version. Added journal reference and DO

Evidence for a mixed mass composition at the `ankle' in the cosmic-ray spectrum

We report a first measurement for ultra-high energy cosmic rays of the correlation between the depth of shower maximum and the signal in the water Cherenkov stations of air-showers registered simultaneously by the fluorescence and the surface detectors of the Pierre Auger Observatory. Such a correlation measurement is a unique feature of a hybrid air-shower observatory with sensitivity to both the electromagnetic and muonic components. It allows an accurate determination of the spread of primary masses in the cosmic-ray flux. Up till now, constraints on the spread of primary masses have been dominated by systematic uncertainties. The present correlation measurement is not affected by systematics in the measurement of the depth of shower maximum or the signal in the water Cherenkov stations. The analysis relies on general characteristics of air showers and is thus robust also with respect to uncertainties in hadronic event generators. The observed correlation in the energy range around the `ankle' at $\lg(E/{\rm eV})=18.5-19.0$ differs significantly from expectations for pure primary cosmic-ray compositions. A light composition made up of proton and helium only is equally inconsistent with observations. The data are explained well by a mixed composition including nuclei with mass $A > 4$. Scenarios such as the proton dip model, with almost pure compositions, are thus disfavoured as the sole explanation of the ultrahigh-energy cosmic-ray flux at Earth.Comment: Published version. Added journal reference and DOI. Added Report Numbe