Haplotypic characterization of the olive ridley turtle (Lepidochelys olivacea) in northwest Mexico: the northernmost limit of its distribution

Caracterización haplotípica de la tortuga golfina (Lepidochelys olivacea) en el noroeste de México: el límite septentrional de su distribución La tortuga golfina (L. olivacea) tiene una distribución pantropical. En el Pacífico oriental, los límites oficiales de su zona de reproducción son la península de Baja California y el sur de Sinaloa, en México. La playa de Ceuta en Elota, Sinaloa, México ha servido de sitio de protección para L. olivacea durante más de tres decenios. En este estudio, se caracterizó genéticamente la población de L. olivacea de la playa de Ceuta. Concretamente, se amplificó un fragmento de 712 pb de la región de control del ADNmt de 32 tortugas golfinas. Se identificaron ocho haplotipos (siete tras reducir a ~468 pb) y se incluyeron dos haplotipos nuevos (Lo–T7 y Lo–T8) y cinco haplotipos que se habían identificado anteriormente en otras playas de anidación. El haplotipo Lo–T2 era dominante (~60 %) en las muestras: h = 0,6048 (± 0,0974) y π = 0,002212 (± 0,001504). Si bien este estudio se realizó en el límite septentrional de la zona de anidación de la tortuga golfina en el Pacífico oriental, el grupo estudiado presenta una diversidad genética moderada y pertenece a una población que, en la escala evolutiva, ha pasado recientemente por una expansión demográfica. Debido a que la tortuga golfina del Pacífico oriental se considera resiliente a la variación ambiental, es necesario estudiar las zonas de anidación en el noroeste de México.The olive ridley sea turtle (L. olivacea) has a pantropical distribution. In the Eastern Pacific, the official limits of its reproduction area are south of the Baja California peninsula and south of Sinaloa, Mexico. Ceuta beach in Elota, Sinaloa, Mexico, has served as a protection site for L. olivacea for over three decades. In this study, the L. olivacea population from Ceuta beach was genetically characterized. Specifically, a 712–bp fragment from the control region of mtDNA was amplified from 32 olive ridley turtles. Eight haplotypes (seven after cutting to ~468 bp) were identified, and these included two novel haplotypes (Lo–T7 and Lo–T8) and five haplotypes that were previously identified in other nesting beaches. The Lo–T2 haplotype was dominant (~60 %) in the samples: h = 0.6048 (± 0.0974) and π = 0.002212 (± 0.001504). Although this study was conducted in the northernmost limit of the olive ridley turtle nesting distribution in the eastern Pacific, the sampled group presents moderate genetic diversity and belongs to a population that, on an evolutionary scale, only recently underwent demographic expansion. Because the olive ridley turtle in the eastern Pacific is considered resilient to environmental variation, nesting area studies in northwest Mexico are necessary.Caracterización haplotípica de la tortuga golfina (Lepidochelys olivacea) en el noroeste de México: el límite septentrional de su distribución La tortuga golfina (L. olivacea) tiene una distribución pantropical. En el Pacífico oriental, los límites oficiales de su zona de reproducción son la península de Baja California y el sur de Sinaloa, en México. La playa de Ceuta en Elota, Sinaloa, México ha servido de sitio de protección para L. olivacea durante más de tres decenios. En este estudio, se caracterizó genéticamente la población de L. olivacea de la playa de Ceuta. Concretamente, se amplificó un fragmento de 712 pb de la región de control del ADNmt de 32 tortugas golfinas. Se identificaron ocho haplotipos (siete tras reducir a ~468 pb) y se incluyeron dos haplotipos nuevos (Lo–T7 y Lo–T8) y cinco haplotipos que se habían identificado anteriormente en otras playas de anidación. El haplotipo Lo–T2 era dominante (~60 %) en las muestras: h = 0,6048 (± 0,0974) y π = 0,002212 (± 0,001504). Si bien este estudio se realizó en el límite septentrional de la zona de anidación de la tortuga golfina en el Pacífico oriental, el grupo estudiado presenta una diversidad genética moderada y pertenece a una población que, en la escala evolutiva, ha pasado recientemente por una expansión demográfica. Debido a que la tortuga golfina del Pacífico oriental se considera resiliente a la variación ambiental, es necesario estudiar las zonas de anidación en el noroeste de México

Doping Liquid Argon with Xenon in ProtoDUNE Single-Phase: Effects on Scintillation Light

International audienceDoping of liquid argon TPCs (LArTPCs) with a small concentration of xenon is a technique for light-shifting and facilitates the detection of the liquid argon scintillation light. In this paper, we present the results of the first doping test ever performed in a kiloton-scale LArTPC. From February to May 2020, we carried out this special run in the single-phase DUNE Far Detector prototype (ProtoDUNE-SP) at CERN, featuring 770 t of total liquid argon mass with 410 t of fiducial mass. The goal of the run was to measure the light and charge response of the detector to the addition of xenon, up to a concentration of 18.8 ppm. The main purpose was to test the possibility for reduction of non-uniformities in light collection, caused by deployment of photon detectors only within the anode planes. Light collection was analysed as a function of the xenon concentration, by using the pre-existing photon detection system (PDS) of ProtoDUNE-SP and an additional smaller set-up installed specifically for this run. In this paper we first summarize our current understanding of the argon-xenon energy transfer process and the impact of the presence of nitrogen in argon with and without xenon dopant. We then describe the key elements of ProtoDUNE-SP and the injection method deployed. Two dedicated photon detectors were able to collect the light produced by xenon and the total light. The ratio of these components was measured to be about 0.65 as 18.8 ppm of xenon were injected. We performed studies of the collection efficiency as a function of the distance between tracks and light detectors, demonstrating enhanced uniformity of response for the anode-mounted PDS. We also show that xenon doping can substantially recover light losses due to contamination of the liquid argon by nitrogen

Doping Liquid Argon with Xenon in ProtoDUNE Single-Phase: Effects on Scintillation Light

International audienceDoping of liquid argon TPCs (LArTPCs) with a small concentration of xenon is a technique for light-shifting and facilitates the detection of the liquid argon scintillation light. In this paper, we present the results of the first doping test ever performed in a kiloton-scale LArTPC. From February to May 2020, we carried out this special run in the single-phase DUNE Far Detector prototype (ProtoDUNE-SP) at CERN, featuring 770 t of total liquid argon mass with 410 t of fiducial mass. The goal of the run was to measure the light and charge response of the detector to the addition of xenon, up to a concentration of 18.8 ppm. The main purpose was to test the possibility for reduction of non-uniformities in light collection, caused by deployment of photon detectors only within the anode planes. Light collection was analysed as a function of the xenon concentration, by using the pre-existing photon detection system (PDS) of ProtoDUNE-SP and an additional smaller set-up installed specifically for this run. In this paper we first summarize our current understanding of the argon-xenon energy transfer process and the impact of the presence of nitrogen in argon with and without xenon dopant. We then describe the key elements of ProtoDUNE-SP and the injection method deployed. Two dedicated photon detectors were able to collect the light produced by xenon and the total light. The ratio of these components was measured to be about 0.65 as 18.8 ppm of xenon were injected. We performed studies of the collection efficiency as a function of the distance between tracks and light detectors, demonstrating enhanced uniformity of response for the anode-mounted PDS. We also show that xenon doping can substantially recover light losses due to contamination of the liquid argon by nitrogen

Doping Liquid Argon with Xenon in ProtoDUNE Single-Phase: Effects on Scintillation Light

International audienceDoping of liquid argon TPCs (LArTPCs) with a small concentration of xenon is a technique for light-shifting and facilitates the detection of the liquid argon scintillation light. In this paper, we present the results of the first doping test ever performed in a kiloton-scale LArTPC. From February to May 2020, we carried out this special run in the single-phase DUNE Far Detector prototype (ProtoDUNE-SP) at CERN, featuring 770 t of total liquid argon mass with 410 t of fiducial mass. The goal of the run was to measure the light and charge response of the detector to the addition of xenon, up to a concentration of 18.8 ppm. The main purpose was to test the possibility for reduction of non-uniformities in light collection, caused by deployment of photon detectors only within the anode planes. Light collection was analysed as a function of the xenon concentration, by using the pre-existing photon detection system (PDS) of ProtoDUNE-SP and an additional smaller set-up installed specifically for this run. In this paper we first summarize our current understanding of the argon-xenon energy transfer process and the impact of the presence of nitrogen in argon with and without xenon dopant. We then describe the key elements of ProtoDUNE-SP and the injection method deployed. Two dedicated photon detectors were able to collect the light produced by xenon and the total light. The ratio of these components was measured to be about 0.65 as 18.8 ppm of xenon were injected. We performed studies of the collection efficiency as a function of the distance between tracks and light detectors, demonstrating enhanced uniformity of response for the anode-mounted PDS. We also show that xenon doping can substantially recover light losses due to contamination of the liquid argon by nitrogen