Validation of close‐kin mark–recapture (CKMR) methods for estimating population abundance

Under embargo until: 2020-06-181. Knowing how many individuals there are in a population is a fundamental problem in the management and conservation of freshwater and marine fish. We compare abundance estimates (census size, Nc) in seven brook trout Salvelinus fontinalis populations using standard mark–recapture (MR) and the close‐kin mark–recapture (CKMR) method. Our purpose is to validate CKMR as a method for estimating population size. 2. Close‐kin mark–recapture is based on the principle that an individual's genotype can be considered a “recapture” of the genotypes of each of its parents. Assuming offspring and parents are sampled independently, the number of parent–offspring pairs (POPs) genetically identified in these samples can be used to estimate abundance. We genotyped (33 microsatellites) and aged c. 2,400 brook trout individuals collected over 5 consecutive years (2014–2018). 3. We provide an alternative interpretation of CKMR in terms of the Lincoln– Petersen estimator in which the parents are considered as tagging the offspring rather than the offspring “recapturing” the parents. 4. Despite various sources of uncertainty, we find close agreement between standard MR abundance estimates obtained through double‐pass electrofishing and CKMR estimates, which require information on age‐specific fecundity, and population‐ and age‐specific survival rates. Population sizes (N) are estimated to range between 300 and 6,000 adult individuals. Our study constitutes the first in situ validation of CKMR and establishes it as a useful method for estimating population size in aquatic systems where assumptions of random sampling and thorough mixing of individuals can be met.acceptedVersio

Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network

Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects

Hemorrhagic transformation of acute ischemic stroke is limited in hypertensive patients with cardiac hypertrophy

BACKGROUND: It has been clearly demonstrated that hypertension and one of its main evoked effects, cardiac hypertrophy, are independent risk factors for ischemic stroke. However, the ischemic brain lesions can further be affected by a second wave of injury characterized by hemorrhagic transformation (HT) of the primary ischemic lesion, which significantly aggravates the clinical outcome. So far, the risk factors that could affect such a transition in hypertensive patients are still unclear. METHODS: In this study, we investigated whether in hypertensive patients the concomitant presence of cardiac hypertrophy can affect the transition of ischemic brain lesions toward HT. RESULTS: Our analysis was focused on a population of hypertensive patients admitted to our Acute Stroke Unit. The hypertensives with acute ischemic stroke suffering of HT were 18% of the sample. In these latter, the prevalence of cardiac hypertrophy was significantly lower than in those spared by HT as also shown by the levels of left ventricular mass index (LVMI) that were significantly higher in patients spared by HT. More important, cardiac hypertrophy was protective even from symptomatic HT. CONCLUSION: Here we show that hypertensive patients with cardiac hypertrophy have less probability to develop HT during an acute episode of ischemic stroke. These results could help to identify patients with lower risk of spontaneous HT and that could have better beneficial effects from thrombolytic therapy during acute ischemic stroke

Validation of close‐kin mark–recapture (CKMR) methods for estimating population abundance

1. Knowing how many individuals there are in a population is a fundamental problem in the management and conservation of freshwater and marine fish. We compare abundance estimates (census size, Nc) in seven brook trout Salvelinus fontinalis populations using standard mark–recapture (MR) and the close‐kin mark–recapture (CKMR) method. Our purpose is to validate CKMR as a method for estimating population size. 2. Close‐kin mark–recapture is based on the principle that an individual's genotype can be considered a “recapture” of the genotypes of each of its parents. Assuming offspring and parents are sampled independently, the number of parent–offspring pairs (POPs) genetically identified in these samples can be used to estimate abundance. We genotyped (33 microsatellites) and aged c. 2,400 brook trout individuals collected over 5 consecutive years (2014–2018). 3. We provide an alternative interpretation of CKMR in terms of the Lincoln– Petersen estimator in which the parents are considered as tagging the offspring rather than the offspring “recapturing” the parents. 4. Despite various sources of uncertainty, we find close agreement between standard MR abundance estimates obtained through double‐pass electrofishing and CKMR estimates, which require information on age‐specific fecundity, and population‐ and age‐specific survival rates. Population sizes (N) are estimated to range between 300 and 6,000 adult individuals. Our study constitutes the first in situ validation of CKMR and establishes it as a useful method for estimating population size in aquatic systems where assumptions of random sampling and thorough mixing of individuals can be met

Augmented reality (AR) in minimally invasive surgery (MIS) training: where are we now in Italy? The Italian Society of Endoscopic Surgery (SICE) ARMIS survey

Minimally invasive surgery (MIS) is a widespread approach in general surgery. Computer guiding software, such as the augmented reality (AR), the virtual reality (VR) and mixed reality (MR), has been proposed to help surgeons during MIS. This study aims to report these technologies' current knowledge and diffusion during surgical training in Italy. A web-based survey was developed under the aegis of the Italian Society of Endoscopic Surgery (SICE). Two hundred and seventeen medical doctors' answers were analyzed. Participants were surgeons (138, 63.6%) and residents in surgery (79, 36.4%). The mean knowledge of the role of the VR, AR and MR in surgery was 4.9 ± 2.4 (range 1-10). Most of the participants (122, 56.2%) did not have experience with any proposed technologies. However, although the lack of experience in this field, the answers about the functioning of the technologies were correct in most cases. Most of the participants answered that VR, AR and MR should be used more frequently for the teaching and training and during the clinical activity (170, 80.3%) and that such technologies would make a significant contribution, especially in training (183, 84.3%) and didactic (156, 71.9%). Finally, the main limitations to the diffusion of these technologies were the insufficient knowledge (182, 83.9%) and costs (175, 80.6%). Based on the present study, in Italy, the knowledge and dissemination of these technologies are still limited. Further studies are required to establish the usefulness of AR, VR and MR in surgical training