Mapping TLE orbital parameters to GNSS ephemeris for LEO PNT mega-constellation orbit simulations and visibility analysis

The emergence of Low Earth Orbit (LEO) satellite constellations dedicated to positioning applications holds the promise of improving the capabilities of existing Global Navigation Satellite Systems (GNSS). However, the absence of operational systems necessitates a qualitative assessment of potential improvements through simulation. This paper introduces a methodology to convert Two Line Element (TLE) orbital parameters, abundantly available for LEO constellations for communication and Earth Observation, into the widely used RINEX 4 format employed by GNSS. The primary goal is to establish a comprehensive database of LEO constellation orbits directly compatible with the orbit propagation algorithms utilized in GNSS systems like the Global Positioning System (GPS). This approach enables seamless integration into simulation tools with minimal adjustments. While TLE parameters are optimized for the SGP4 propagation model and cautioned against use in classical Kepler orbit propagation scenarios requiring precision, the obtained discrepancies, within a few tens of kilometers, suggest that these representations are realistic for simulation purposes, as demonstrated with the Spire LEMUR LEO constellation. As a practical application, the paper conducts a visibility analysis using the Starlink constellation. Results affirm expectations, showcasing that the combination of GNSS with a LEO mega-constellation significantly enhances satellite coverage and reduces Dilution of Precision. This work contributes to the ongoing discourse on the potential benefits and practicality of integrating emerging LEO constellations with established GNSS systems, offering insights into improved navigation and timing capabilities through simulation-based assessments.Comment: 7 pages, 4 figures, pre-prin

Association of birth weight and the development of antipsychotic induced adiposity in individuals with treatment resistant schizophrenia.

Though weight gain is a common side effect of antipsychotic treatment, there are no useful predictors of which patients are likely to be affected and to what degree. It has been shown that exposure to adverse conditions during intra-uterine life confers a vulnerability to the development of later life metabolic complications and low birth weight for gestational age has been shown to be a robust marker of such prenatal adversity. We hypothesised that patients with schizophrenia with a lower birth weight will have increased vulnerability to the weight inducing effects of antipsychotic treatment. The relationship between birth weight and total and central adiposity, measured as body mass index (BMI) and waist-to-hip ratio (WHR) respectively, was examined in three groups: drug naïve first episode of psychosis (FEP) patients (n=41), treatment resistant schizophrenia (TRS) patients (n=42) and matched healthy volunteers (n=72). All analyses were controlled for age, gender and duration of treatment exposure. We found that a lower birth weight was associated with higher BMI and WHR only in TRS patients but not in FEP or controls, suggesting that prenatal adversity, as indicated by the surrogate marker of a lower birth weight, confers an increased vulnerability to clozapine induced weight gain.This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.euroneuro.2016.03.00

The AXIOM software layers

AXIOM project aims at developing a heterogeneous computing board (SMP-FPGA).The Software Layers developed at the AXIOM project are explained.OmpSs provides an easy way to execute heterogeneous codes in multiple cores. People and objects will soon share the same digital network for information exchange in a world named as the age of the cyber-physical systems. The general expectation is that people and systems will interact in real-time. This poses pressure onto systems design to support increasing demands on computational power, while keeping a low power envelop. Additionally, modular scaling and easy programmability are also important to ensure these systems to become widespread. The whole set of expectations impose scientific and technological challenges that need to be properly addressed.The AXIOM project (Agile, eXtensible, fast I/O Module) will research new hardware/software architectures for cyber-physical systems to meet such expectations. The technical approach aims at solving fundamental problems to enable easy programmability of heterogeneous multi-core multi-board systems. AXIOM proposes the use of the task-based OmpSs programming model, leveraging low-level communication interfaces provided by the hardware. Modular scalability will be possible thanks to a fast interconnect embedded into each module. To this aim, an innovative ARM and FPGA-based board will be designed, with enhanced capabilities for interfacing with the physical world. Its effectiveness will be demonstrated with key scenarios such as Smart Video-Surveillance and Smart Living/Home (domotics).Peer ReviewedPostprint (author's final draft

Real-Time and Post-Processed Orbit Determination and Positioning

Novel methods and systems for the accurate and efficient processing of real-time and latent global navigation satellite systems (GNSS) data are described. Such methods and systems can perform orbit determination of GNSS satellites, orbit determination of satellites carrying GNSS receivers, positioning of GNSS receivers, and environmental monitoring with GNSS data

The PAU Survey: Photometric redshifts using transfer learning from simulations

In this paper we introduce the \textsc{Deepz} deep learning photometric redshift (photo-$z$) code. As a test case, we apply the code to the PAU survey (PAUS) data in the COSMOS field. \textsc{Deepz} reduces the $\sigma_{68}$ scatter statistic by 50\% at $i_{\rm AB}=22.5$ compared to existing algorithms. This improvement is achieved through various methods, including transfer learning from simulations where the training set consists of simulations as well as observations, which reduces the need for training data. The redshift probability distribution is estimated with a mixture density network (MDN), which produces accurate redshift distributions. Our code includes an autoencoder to reduce noise and extract features from the galaxy SEDs. It also benefits from combining multiple networks, which lowers the photo-$z$ scatter by 10 percent. Furthermore, training with randomly constructed coadded fluxes adds information about individual exposures, reducing the impact of photometric outliers. In addition to opening up the route for higher redshift precision with narrow bands, these machine learning techniques can also be valuable for broad-band surveys.Comment: Accepted versio

The effect of early life events on glucose levels in first-episode psychosis

First episode of psychosis (FEP) patients display a wide variety of metabolic disturbances at onset, which might underlie these patients’ increased morbidity and early mortality. Glycemic abnormalities have been previously related to pharmacological agents; however, recent research highlights the impact of early life events. Birth weight (BW), an indirect marker of the fetal environment, has been related to glucose abnormalities in the general population over time. We aim to evaluate if BW correlates with glucose values in a sample of FEP patients treated with different antipsychotics. Two hundred and thirty-six patients were included and evaluated for clinical and metabolic variables at baseline and at 2, 6, 12, and 24 months of follow-up. Pearson correlations and linear mixed model analysis were conducted to analyze the data. Antipsychotic treatment was grouped due to its metabolic risk profile. In our sample of FEP patients, BW was negatively correlated with glucose values at 24 months of follow-up [r=-0.167, p=0.037]. BW showed a trend towards significance in the association with glucose values over the 24-month period (F=3.22; p=0.073) despite other confounders such as age, time, sex, body mass index, antipsychotic type, and chlorpromazine dosage. This finding suggests that BW is involved in the evolution of glucose values over time in a cohort of patients with an FEP, independently of the type of pharmacological agent used in treatment. Our results highlight the importance of early life events in the later metabolic outcome of patients

The PAU Survey: a new constraint on galaxy formation models using the observed colour redshift relation

We use the GALFORM semi-analytical galaxy formation model implemented in the Planck Millennium N-body simulation to build a mock galaxy catalogue on an observer's past lightcone. The mass resolution of this N-body simulation is almost an order of magnitude better than in previous simulations used for this purpose, allowing us to probe fainter galaxies and hence build a more complete mock catalogue at low redshifts. The high time cadence of the simulation outputs allows us to make improved calculations of galaxy properties and positions in the mock. We test the predictions of the mock against the Physics of the Accelerating Universe Survey, a narrow band imaging survey with highly accurate and precise photometric redshifts, which probes the galaxy population over a lookback time of 8 billion years. We compare the model against the observed number counts, redshift distribution and evolution of the observed colours and find good agreement; these statistics avoid the need for model-dependent processing of the observations. The model produces red and blue populations that have similar median colours to the observations. However, the bimodality of galaxy colours in the model is stronger than in the observations. This bimodality is reduced on including a simple model for errors in the GALFORM photometry. We examine how the model predictions for the observed galaxy colours change when perturbing key model parameters. This exercise shows that the median colours and relative abundance of red and blue galaxies provide constraints on the strength of the feedback driven by supernovae used in the model

TESLA Technical Design Report Part III: Physics at an e+e- Linear Collider

The TESLA Technical Design Report Part III: Physics at an e+e- Linear ColliderComment: 192 pages, 131 figures. Some figures have reduced quality. Full quality figures can be obtained from http://tesla.desy.de/tdr. Editors - R.-D. Heuer, D.J. Miller, F. Richard, P.M. Zerwa