Activity time series of old stars from late F to early K VI. Exoplanet mass characterisation and detectability in radial velocity

Stellar variability impacts radial velocities at various timescales and therefore the detectability of exoplanets and the mass determination based on this technique. It is necessary to implement systematic studies, to delineate the current limitations of RV techniques to detect Earth-like planets. This paper aims are to investigate whether the targeted 10% mass uncertainty from RV follow-up of transits detected by PLATO can be reached, and to analyse and quantify Earth-like planet detectability for various spectral types. We implemented blind tests based on a large data set of realistic synthetic time series reproducing different phenomena leading to stellar variability such as complex magnetic activity patterns as well as flows, covering F6-K4 stars and a wide range of activity levels. The 10% mass uncertainty for a 1 MEarth in the habitable zone of a G2 star cannot be reached, even with an improved version of a usual correction of stellar activity and even for long-duration (ten years) well-sampled observations. This level can be reached for masses above 3 MEarth or for K4 stars alone. We quantify the maximum dispersion of the RV residuals needed to reach this 10% level, assuming the correction method and models do not affect the planetary signal. Several other methods were tested and do not allow a significantly improvement of this limited performance. Similarly, such low-mass planets in the habitable zone cannot be detected with a similar correction: blind tests lead to very low detection rates for 1 MEarth and a very high level of false positives. Very significant and new improvements with respect to methods based on activity indicators to correct for stellar activity must be devised at all timescales to reach the objective of 10% uncertainty on the mass or to detect such planets in RV. Methods based on the correlation with activity indicators are unlikely to be sufficient.Comment: Paper accepted in Astronomy and Astrophysic

DC-SIGN Is the Major Mycobacterium tuberculosis Receptor on Human Dendritic Cells

Early interactions between lung dendritic cells (LDCs) and Mycobacterium tuberculosis, the etiological agent of tuberculosis, are thought to be critical for mounting a protective anti-mycobacterial immune response and for determining the outcome of infection. However, these interactions are poorly understood, at least at the molecular level. Here we show that M. tuberculosis enters human monocyte-derived DCs after binding to the recently identified lectin DC-specific intercellular adhesion molecule-3 grabbing nonintegrin (DC-SIGN). By contrast, complement receptor (CR)3 and mannose receptor (MR), which are the main M. tuberculosis receptors on macrophages (Mφs), appeared to play a minor role, if any, in mycobacterial binding to DCs. The mycobacteria-specific lipoglycan lipoarabinomannan (LAM) was identified as a key ligand of DC-SIGN. Freshly isolated human LDCs were found to express DC-SIGN, and M. tuberculosis–derived material was detected in CD14−HLA-DR+DC-SIGN+ cells in lymph nodes (LNs) from patients with tuberculosis. Thus, as for human immunodeficiency virus (HIV), which is captured by the same receptor, DC-SIGN–mediated entry of M. tuberculosis in DCs in vivo is likely to influence bacterial persistence and host immunity

SPICES: Spectro-Polarimetric Imaging and Characterization of Exoplanetary Systems

SPICES (Spectro-Polarimetric Imaging and Characterization of Exoplanetary Systems) is a five-year M-class mission proposed to ESA Cosmic Vision. Its purpose is to image and characterize long-period extrasolar planets and circumstellar disks in the visible (450 - 900 nm) at a spectral resolution of about 40 using both spectroscopy and polarimetry. By 2020/22, present and near-term instruments will have found several tens of planets that SPICES will be able to observe and study in detail. Equipped with a 1.5 m telescope, SPICES can preferentially access exoplanets located at several AUs (0.5-10 AU) from nearby stars ($<$25 pc) with masses ranging from a few Jupiter masses to Super Earths ($\sim$2 Earth radii, $\sim$10 M$_{\oplus}$) as well as circumstellar disks as faint as a few times the zodiacal light in the Solar System

University of Nebraska Five-Year Strategy, Revised August 12, 2020

The University of Nebraska Five-Year Strategy: Trust, Predictability, and Positive Outcomes for Nebraskans In February 2020, the newly named president of the University of Nebraska system, Ted Carter, gathered a diverse 28-member team of students, faculty, staff, and administrators to help chart the path forward for Nebraska’s public university. The team’s goal: At a time of great change in higher education, lay out a vision for what the future should look like for the University of Nebraska. Broad themes quickly emerged, including student access and success, excellence in teaching and research, diversity and inclusion, partnerships, and fiscal effectiveness. Then COVID-19 hit, forcing a pause in the team’s work. The ensuing months showed that the initial priorities identified by the team were not only still relevant, but more important than ever in defining the future of higher education. From that early work has emerged a five-year strategy for growth and success across the four-campus University of Nebraska system. In addition to the strategic planning team, Carter engaged alumni and donors, elected leaders, leaders in business and agriculture, the Board of Regents, NU senior leadership, and others in conversations about the University’s future. The resulting strategy is built around several key principles: The value of higher education is clear and growing. Nebraska’s success is tied to that of its University. Students come first. The University of Nebraska should be the best place in the country to be a student, providing high-quality, affordable, accessible education that prioritizes students’ mental and physical health and prepares them for post-graduation success. Our people are our greatest asset. We will invest accordingly. We have a responsibility to make the best use of every dollar Nebraskans entrust to us. Themes of equity and inclusion touch everything we do. We will be a University for everyone—successful only when all voices are heard. Finally, Nebraskans should know what to expect from their University. We must work every day to maintain the trust and confidence of the people of our state

Genome-wide detection of a TFIID localization element from an initial human disease mutation

Eukaryotic core promoters are often characterized by the presence of consensus motifs such as the TATA box or initiator elements, which attract and direct the transcriptional machinery to the transcription start site. However, many human promoters have none of the known core promoter motifs, suggesting that undiscovered promoter motifs exist in the genome. We previously identified a mutation in the human Ankyrin-1 (ANK-1) promoter that causes the disease ankyrin-deficient Hereditary Spherocytosis (HS). Although the ANK-1 promoter is CpG rich, no discernable basal promoter elements had been identified. We showed that the HS mutation disrupted the binding of the transcription factor TFIID, the major component of the pre-initiation complex. We hypothesized that the mutation identified a candidate promoter element with a more widespread role in gene regulation. We examined 17 181 human promoters for the experimentally validated binding site, called the TFIID localization sequence (DLS) and found three times as many promoters containing DLS than TATA motifs. Mutational analyses of DLS sequences confirmed their functional significance, as did the addition of a DLS site to a minimal Sp1 promoter. Our results demonstrate that novel promoter elements can be identified on a genome-wide scale through observations of regulatory disruptions that cause human disease

Genome-wide Analyses Identify KIF5A as a Novel ALS Gene

To identify novel genes associated with ALS, we undertook two lines of investigation. We carried out a genome-wide association study comparing 20,806 ALS cases and 59,804 controls. Independently, we performed a rare variant burden analysis comparing 1,138 index familial ALS cases and 19,494 controls. Through both approaches, we identified kinesin family member 5A (KIF5A) as a novel gene associated with ALS. Interestingly, mutations predominantly in the N-terminal motor domain of KIF5A are causative for two neurodegenerative diseases: hereditary spastic paraplegia (SPG10) and Charcot-Marie-Tooth type 2 (CMT2). In contrast, ALS-associated mutations are primarily located at the C-terminal cargo-binding tail domain and patients harboring loss-of-function mutations displayed an extended survival relative to typical ALS cases. Taken together, these results broaden the phenotype spectrum resulting from mutations in KIF5A and strengthen the role of cytoskeletal defects in the pathogenesis of ALS.Peer reviewe

COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P &lt; 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

Asymptotic Analysis of Area Spectral Efficiency and Energy Efficiency in PPP Networks with SLNR Precoder

International audienceThis paper aims at characterizing the energy efficiency area spectral efficiency (EE-ASE) tradeoff in random geometry networks with multiple-antenna arrays at base stations (BSs). In particular, ASE and EE are studied w.r.t. the transmit power when BSs use a signal-to-leakage-plus-noise ratio (SLNR) precoder. When the static power consumption cannot be neglected, EE behaves linearly w.r.t. ASE before a sharp decreasing of EE due to the interference-limited characteristic of the network. Our contribution relies on the derivation of a closed-form expression for ASE with SLNR precoder in the asymptotic regime, i.e. when the number of antennas and users grows to infinity, using stochastic geometry. We derive EE from a linear power consumption model afterwards. Unlike conventional SLNR precoders, the average signal-to-interference-plus-noise ratio and the leakage to other cells are considered in a geometry dependent network. Extensive Monte Carlo simulations show that despite the asymptotic nature of the theoretical analysis, the closed-form expressions are tight w.r.t. simulations even for moderate number of antennas and users. Hence, the analysis can be used for realistic network performance analysis

Energy Efficiency-Area Spectral Efficiency Tradeoff in PPP Network with SLNR Precoder

International audienceSignal-to-leakage-and-noise ratio (SLNR) is a pro\-mising criterion for linear precoder design in multiuser multiple-input multiple-output systems. In this paper, an expression of a precoder maximizing the SLNR based on the generalized Rayleigh quotient theorem is derived for cellular networks. Compared with the conventional SLNR precoders, we consider the non-homogeneous average received signal-to-noise ratio (SNR) condition due to the random network geometry and the leakage to other cells. We aim at characterizing the energy efficiency-area spectral efficiency (EE-ASE) region for a Poisson point process (PPP) network using this precoder for different base station (BS) densities and number of BS antennas when static power consumption is considered. Simulation results demonstrate the superiority of the SLNR precoder over zero-forcing (ZF) precoder in terms of EE-ASE tradeoff. Our contribution lies in the analysis of the performance of SLNR precoder in PPP networks in terms of tradeoff between EE and SE, and in the comparison between the well known ZF precoder and SLNR precoder, when static power consumption is considered

Compromis efficacités énergétique et spectrale du précodeur SLNR dans un réseau cellulaire aléatoire

National audienceThe performance of the precoder maximizing the signal-to-leakage-plus-noise ratio (SLNR) is investigated in terms of tradeoff between energy and area spectral efficiencies (EE-ASE) in random networks. The comparison between the well known zero-forcing precoder and SLNR precoder is considered with static power consumption of base stations. Moreover, an upper-bound on ASE is proposed based on the large random matrix theory.Les performances du précodeur maximisant le rapport signal sur bruit plus fuite (SLNR) sont étudiées d'un point de vue du compromis entre les efficacités energétique (EE) et spectrale par unité de surface (ASE) dans les réseaux aléatoires. La comparaison avec le précodeur de forçage à zéro est traitée en prenant en compte la puissance statique consommée par les stations de base. De plus, nous proposons une borne supérieure analytique de l'ASE issue d'une étude asymptotique avec les grandes matrices aléatoires