Unboundedness of adjacency matrices of locally finite graphs

Given a locally finite simple graph so that its degree is not bounded, every self-adjoint realization of the adjacency matrix is unbounded from above. In this note we give an optimal condition to ensure it is also unbounded from below. We also consider the case of weighted graphs. We discuss the question of self-adjoint extensions and prove an optimal criterium.Comment: Typos corrected. Examples added. Cute drawings. Simplification of the main condition. Case of the weight tending to zero more discussed

Sécurisation d'un réseau d'équipement loT avec le protocole Oauth

Selon une étude de l’entreprise américaine Gartner, le nombre d’objets (IoT) connectés à internet devrait presque doubler durant les deux prochaines années, passant de 11,1 milliards en 2018 à 20.4 milliards en 2020. La sécurité des IoT n’est pas facile à mettre en place. Certains appareils manquent simplement de puissance de calcul ou de mémoire et peuvent difficilement communiquer de façon sécurisée. D’autre part, une grande partie de l’internet des objets utilise la technologie « machine to machine » (M2M) pour communiquer entre eux et ne passe pas par un serveur centralisé. Le M2M nécessite un certain niveau de confiance entre les objets interconnectés qu’il est difficile de garantir même dans un réseau local. Dans le cadre de la sécurisation de systèmes IoT distribués, il est nécessaire de centraliser le système d’autorisation d’accès aux ressources et de pouvoir gérer et révoquer tout type de client au besoin. Le standard Oauth2.0 fourni les éléments nécessaires pour concevoir le système d’autorisation centralisé d’accès aux services distribués. Cependant, ce protocole est fortement dépendant de TLS. Toute communication doit être sécurisée au travers de requêtes https ce qui élimine de facto une partie non-négligeable des objets connectés actuellement sur le marché. Par ailleurs, en dérogeant légèrement au standard il est possible d’adapter le protocole pour supporter une partie des flux de communication sans TLS tout en offrant les mêmes garanties que dans sa forme initiale

LLAMA : nuclear stellar properties of Swift-BAT AGN and matched inactive galaxies

In a complete sample of local 14–195 keV selected active galactic nuclei (AGNs) and inactive galaxies, matched by their host galaxy properties, we study the spatially resolved stellar kinematics and luminosity distributions at near-infrared wavelengths on scales of 10–150 pc, using SINFONI on the VLT. In this paper, we present the first half of the sample, which comprises 13 galaxies, eight AGNs and five inactive galaxies. The stellar velocity fields show a disc-like rotating pattern, for which the kinematic position angle is in agreement with the photometric position angle obtained from large scale images. For this set of galaxies, the stellar surface brightness of the inactive galaxy sample is generally comparable to the matched sample of AGN, but extends to lower surface brightness. After removal of the bulge contribution, we find a nuclear stellar light excess with an extended nuclear disc structure, which exhibits a size-luminosity relation. While we expect the excess luminosity to be associated with a dynamically cooler young stellar population, we do not typically see a matching drop in dispersion. This may be because these galaxies have pseudo-bulges in which the intrinsic dispersion increases towards the centre. And although the young stars may have an impact in the observed kinematics, their fraction is too small to dominate over the bulge and compensate the increase in dispersion at small radii, so no dispersion drop is seen. Finally, we find no evidence for a difference in the stellar kinematics and nuclear stellar luminosity excess between these active and inactive galaxies

Does maternal environmental condition during reproductive development induce genotypic selection in Picea abies ?

In forest trees, environmental conditions during reproduction can greatly influence progeny performance. This phenomenon probably results from adaptive phenotypic plasticity but also may be associated with genotypic selection. In order to determine whether selective effects during the reproduction are environment specific, single pair-crosses of Norway spruce were studied in two contrasted maternal environments (warm and cold conditions). One family expressed large and the other small phenotypic differences between these crossing environments. The inheritance of genetic polymorphism was analysed at the seed stage. Four parental genetic maps covering 66 to 78% of the genome were constructed using 190 to 200 loci. After correcting for multiple testing, there is no evidence of locus under strong and repeatable selection. The maternal environment could thus only induce limited genotypic-selection effects during reproductive steps, and performance of progenies may be mainly affected by a long-lasting epigenetic memory regulated by temperature and photoperiod prevailing during seed productio

Potential yield simulated by global gridded crop models: using a process-based emulator to explain their differences

How global gridded crop models (GGCMs) differ in their simulation of potential yield and reasons for those differences have never been assessed. The GGCM Intercomparison (GGCMI) offers a good framework for this assessment. Here, we built an emulator (called SMM for simple mechanistic model) of GGCMs based on generic and simplified formalism. The SMM equations describe crop phenology by a sum of growing degree days, canopy radiation absorption by the Beer–Lambert law, and its conversion into aboveground biomass by a radiation use efficiency (RUE). We fitted the parameters of this emulator against gridded aboveground maize biomass at the end of the growing season simulated by eight different GGCMs in a given year (2000). Our assumption is that the simple set of equations of SMM, after calibration, could reproduce the response of most GGCMs so that differences between GGCMs can be attributed to the parameters related to processes captured by the emulator. Despite huge differences between GGCMs, we show that if we fit both a parameter describing the thermal requirement for leaf emergence by adjusting its value to each grid-point in space, as done by GGCM modellers following the GGCMI protocol, and a GGCM-dependent globally uniform RUE, then the simple set of equations of the SMM emulator is sufficient to reproduce the spatial distribution of the original aboveground biomass simulated by most GGCMs. The grain filling is simulated in SMM by considering a fixed-in-time fraction of net primary productivity allocated to the grains (frac) once a threshold in leaves number (nthresh) is reached. Once calibrated, these two parameters allow for the capture of the relationship between potential yield and final aboveground biomass of each GGCM. It is particularly important as the divergence among GGCMs is larger for yield than for aboveground biomass. Thus, we showed that the divergence between GGCMs can be summarized by the differences in a few parameters. Our simple but mechanistic model could also be an interesting tool to test new developments in order to improve the simulation of potential yield at the global scale

Cis-epistasis at the LPA locus and risk of cardiovascular diseases

AIMS Coronary artery disease (CAD) has a strong genetic predisposition. However, despite substantial discoveries made by genome-wide association studies (GWAS), a large proportion of heritability awaits identification. Non-additive genetic-effects might be responsible for part of the unaccounted genetic variance. Here we attempted a proof-of-concept study to identify non-additive genetic effects, namely epistatic interactions, associated with CAD. METHODS AND RESULTS We tested for epistatic interactions in ten CAD case-control studies and UK Biobank with focus on 8,068 SNPs at 56 loci with known associations with CAD risk. We identified a SNP pair located in cis at the LPA locus, rs1800769 and rs9458001, to be jointly associated with risk for CAD (odds ratio OR=1.37, p = 1.07 $\times$ 10-11), peripheral arterial disease (OR = 1.22, p = 2.32 $\times$ 10-4), aortic stenosis (OR = 1.47, p = 6.95 $\times$ 10-7), hepatic lipoprotein(a) (Lp(a)) transcript levels (beta = 0.39, p = 1.41 $\times$ 10-8), and Lp(a) serum levels (beta = 0.58, p = 8.7 $\times$ 10-32), while individual SNPs displayed no association. Further exploration of the LPA locus revealed a strong dependency of these associations on a rare variant, rs140570886, that was previously associated with Lp(a) levels. We confirmed increased CAD risk for heterozygous (relative OR = 1.46, p = 9.97 $\times$ 10-32) and individuals homozygous for the minor allele (relative OR = 1.77, p = 0.09) of rs140570886. Using forward model selection, we also show that epistatic interactions between rs140570886, rs9458001, and rs1800769 modulate the effects of the rs140570886 risk allele. CONCLUSIONS These results demonstrate the feasibility of a large-scale knowledge-based epistasis scan and provide rare evidence of an epistatic interaction in a complex human disease. We were directed to a variant (rs140570886) influencing risk through additive genetic as well as epistatic effects. In summary, this study provides deeper insights into the genetic architecture of a locus important for cardiovascular diseases. TRANSLATIONAL PERSPECTIVE Genetic variants identified by GWAS studies explain about a quarter of the heritability of coronary artery disease by additive genetic effects. Our study demonstrates that non-additive effects contribute to the genetic architecture of the disease as well and identifies complex interaction patterns at the LPA locus, which affect LPA expression, Lp(a) plasma levels and risk of atherosclerosis. This proof-of-concept study encourages systematic searches for epistatic interactions in further studies to shed new light on the aetiology of the disease

Diagnosis of primary ciliary dyskinesia: discrepancy according to different algorithms

Background: Diagnosis of primary ciliary dyskinesia (PCD) is challenging since there is no gold standard test. The European Respiratory (ERS) and American Thoracic (ATS) Societies developed evidence-based diagnostic guidelines with considerable differences. Objective: We aimed to compare the algorithms published by the ERS and the ATS with each other and with our own PCD-UNIBE algorithm in a clinical setting. Our algorithm is similar to the ERS algorithm with additional immunofluorescence staining. Agreement (Cohen's κ) and concordance between the three algorithms were assessed in patients with suspicion of PCD referred to our diagnostic centre. Results: In 46 out of 54 patients (85%) the final diagnosis was concordant between all three algorithms (30 PCD negative, 16 PCD positive). In eight patients (15%) PCD diagnosis differed between the algorithms. Five patients (9%) were diagnosed as PCD only by the ATS, one (2%) only by the ERS and PCD-UNIBE, one (2%) only by the ATS and PCD-UNIBE, and one (2%) only by the PCD-UNIBE algorithm. Agreement was substantial between the ERS and the ATS (κ=0.72, 95% CI 0.53-0.92) and the ATS and the PCD-UNIBE (κ=0.73, 95% CI 0.53-0.92) and almost perfect between the ERS and the PCD-UNIBE algorithms (κ=0.92, 95% CI 0.80-1.00). Conclusion: The different diagnostic algorithms lead to a contradictory diagnosis in a considerable proportion of patients. Thus, an updated, internationally harmonised and standardised PCD diagnostic algorithm is needed to improve diagnostics for these discordant cases

Superfield Noether Procedure

We develop a superspace Noether procedure for supersymmetric field theories in 4-dimensions for which an off-shell formulation in ordinary superspace exists. In this way we obtain an elegant and compact derivation of the various supercurrents in these theories. We then apply this formalism to compute the central charges for a variety of effective actions. As a by-product we also obtain a simple derivation of the anomalous superconformal Ward-identity in N=2 Yang-Mills theory. The connection with linearized supergravity is also discussed.Comment: 47 pages, Latex, improved pedagogical presentation and references adde